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WO2018168846A1 - Dispositif d'affichage à balayage laser avec réglage de la luminance - Google Patents

Dispositif d'affichage à balayage laser avec réglage de la luminance Download PDF

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Publication number
WO2018168846A1
WO2018168846A1 PCT/JP2018/009713 JP2018009713W WO2018168846A1 WO 2018168846 A1 WO2018168846 A1 WO 2018168846A1 JP 2018009713 W JP2018009713 W JP 2018009713W WO 2018168846 A1 WO2018168846 A1 WO 2018168846A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
output power
light source
display device
scanning
Prior art date
Application number
PCT/JP2018/009713
Other languages
English (en)
Inventor
Makoto Inamoto
Yoshinori Hayashi
Hiroyuki Tanabe
Original Assignee
Ricoh Company, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2018006229A external-priority patent/JP2018156062A/ja
Application filed by Ricoh Company, Ltd. filed Critical Ricoh Company, Ltd.
Priority to US16/486,929 priority Critical patent/US10950152B2/en
Priority to EP18715989.2A priority patent/EP3596529A1/fr
Publication of WO2018168846A1 publication Critical patent/WO2018168846A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2053—Intensity control of illuminating light
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/02—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes by tracing or scanning a light beam on a screen
    • G09G3/025—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes by tracing or scanning a light beam on a screen with scanning or deflecting the beams in two directions or dimensions
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3129—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] scanning a light beam on the display screen
    • H04N9/3135—Driving therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3152—Modulator illumination systems for shaping the light beam
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B2027/0118—Head-up displays characterised by optical features comprising devices for improving the contrast of the display / brillance control visibility
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G09G2320/064—Adjustment of display parameters for control of overall brightness by time modulation of the brightness of the illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0666—Adjustment of display parameters for control of colour parameters, e.g. colour temperature
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2360/00—Aspects of the architecture of display systems
    • G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
    • G09G2360/144—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light being ambient light
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2380/00—Specific applications
    • G09G2380/10—Automotive applications
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3433—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices
    • G09G3/346—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices based on modulation of the reflection angle, e.g. micromirrors

Definitions

  • the present invention relates to a display device, an object apparatus and a display method.
  • the device disclosed in PLT 1 still has room for improvement in terms of adjusting luminance of an image while controlling against luminance unevenness of the image from occurring.
  • One aspect of the present invention provides a display device for scanning with light emitted by a light source an optical element array including a plurality of optical elements to form an image and for projecting the light forming the image, the display device comprising a control unit that is capable of changing output power of the light source while each of the plurality of optical elements is being scanned.
  • the present invention it is possible to adjust luminance of an image while controlling against luminance unevenness of the image from occurring.
  • FIG. 1 is a drawing illustrating an overall configuration of a head-up display (HUD) device according to an embodiment of the present invention
  • FIG. 2 is a block diagram illustrating a hardware configuration of a control system of the HUD device according to the embodiment of the present invention
  • FIG. 3 is a functional block diagram of the HUD device according to the embodiment of the present invention
  • FIG. 4 is a drawing for explaining a light source device of the HUD device according to the embodiment of the present invention
  • FIG. 5 is a drawing for explaining a light deflector of the HUD device according to the embodiment of the present invention
  • FIG. 6 is a drawing illustrating a correspondence relation between a mirror of the light deflector and a scanning region, according to the embodiment of the present invention
  • FIG. 1 is a drawing illustrating an overall configuration of a head-up display (HUD) device according to an embodiment of the present invention
  • FIG. 2 is a block diagram illustrating a hardware configuration of a control system of the HUD device according to the embodiment of the
  • FIG. 7 is a drawing illustrating an example of a trajectory of a scanning line at a time of two-dimensional scanning, according to the embodiment of the present invention
  • FIG. 8A is a drawing for explaining a difference in effects, which is caused by difference in sizes of a luminous flux diameter of incident light and a lens diameter of a micro-lens array, according to the embodiment of the present invention
  • FIG. 8B is a drawing for explaining a difference in effects, which is caused by difference in sizes of a luminous flux diameter of incident light and a lens diameter of a micro-lens array, according to the embodiment of the present invention
  • FIG. 9 is a drawing for explaining a scanning line of the micro-lens array, according to the embodiment of the present invention.
  • FIG. 10 is a drawing for explaining beam spots on the micro-lens array, according to the embodiment of the present invention
  • FIG. 11 is a drawing illustrating a relation between a position of a micro lens at which luminous flux is incident and intensity of a point on the micro lens, according to the embodiment of the present invention
  • FIG. 12 is a drawing for explaining intensity distribution of points formed on the micro-lens array in a case of continuously lighting a light source at constant output power, according to the embodiment of the present invention
  • FIG. 13 is a drawing for explaining intensity distribution of points formed on the micro-lens array in a case of executing a high output power mode and a low output power mode while each micro lens is being scanned, according to the embodiment of the present invention
  • FIG. 11 is a drawing illustrating a relation between a position of a micro lens at which luminous flux is incident and intensity of a point on the micro lens, according to the embodiment of the present invention
  • FIG. 12 is a drawing for explaining intensity distribution of points formed on the micro
  • FIG. 14 is a drawing for explaining intensity distribution of points formed on the micro-lens array in a case of performing decreased lighting, according to the embodiment of the present invention
  • FIG. 15A is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention
  • FIG. 15B is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention
  • FIG. 15C is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention
  • FIG. 15D is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention
  • FIG. 15E is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention
  • FIG. 15A is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention
  • FIG. 15B is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention
  • FIG. 15C is a drawing for explaining
  • FIG. 15F is a drawing for explaining a specific example of an output pattern, according to the embodiment of the present invention.
  • FIG. 16 is a drawing for explaining a relation of a decrease cycle, a lens cycle and the moire phenomenon, according to the embodiment of the present invention;
  • FIG. 17A is a drawing for explaining a relation between an effective diameter of incident luminous flux and a distance between adjacent high power rendered points, according to the embodiment of the present invention;
  • FIG. 17B is a drawing for explaining a relation between an effective diameter of incident luminous flux and a distance between adjacent high power rendered points, according to the embodiment of the present invention;
  • FIG. 18 is a drawing illustrating a configuration of a light source device in a variation example, according to the embodiment of the present invention;
  • FIG. 19A is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens, according to the embodiment of the present invention
  • FIG. 19B is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens, according to the embodiment of the present invention
  • FIG. 19C is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens, according to the embodiment of the present invention
  • FIG. 19D is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens, according to the embodiment of the present invention
  • FIG. 19E is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens, according to the embodiment of the present invention
  • FIG. 19F is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens, according to the embodiment of the present invention
  • FIG. 19B is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens, according to the embodiment of the present invention
  • FIG. 19C is a drawing for explaining micro lens alignment and an aspect ratio of a micro lens,
  • FIG. 20 is a block diagram illustrating a configuration example of a control unit of an image rendering unit, according to the embodiment of the present invention
  • FIG. 21 is a flowchart for explaining a display process, according to the embodiment of the present invention
  • FIG. 22A is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention
  • FIG. 22B is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention
  • FIG. 22C is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention
  • FIG. 22D is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention
  • FIG. 22E is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention
  • FIG. 22A is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention
  • FIG. 22B is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention
  • FIG. 22C
  • FIG. 22F is a drawing for explaining another example of an output pattern, according to the embodiment of the present invention.
  • FIG. 23A is a drawing for explaining still another example of an output pattern, according to the embodiment of the present invention
  • FIG. 23B is a drawing for explaining still another example of an output pattern, according to the embodiment of the present invention
  • FIG. 23C is a drawing for explaining still another example of an output pattern, according to the embodiment of the present invention
  • FIG. 23D is a drawing for explaining still another example of an output pattern, according to the embodiment of the present invention
  • FIG. 23E is a drawing for explaining still another example of an output pattern, according to the embodiment of the present invention
  • FIG. 23F is a drawing for explaining still another example of an output pattern, according to the embodiment of the present invention.
  • HUD head-up display
  • FIG. 1 an overall configuration of an HUD device 100 according to the present embodiment is schematically illustrated.
  • Overall Configuration of an HUD device is schematically illustrated.
  • projection methods for a head-up display include: a "panel method”, in which an intermediate image is formed by means of an imaging device such as a liquid crystal panel, a digital mirror device (DMD) panel or a vacuum fluorescent display (VFD); and a “laser scanning method”, in which an intermediate image is formed by means of a two-dimensional scanning device that performs scanning with a laser beam emitted by a laser light source.
  • a laser scanning method in which an intermediate image is formed by means of a two-dimensional scanning device that performs scanning with a laser beam emitted by a laser light source.
  • emission or non-emission of light can be assigned for each pixel.
  • the "laser scanning method” is employed for the HUD device 100.
  • the "panel method” as described above may be employed as a projection method as well.
  • the HUD device 100 may be mounted on a vehicle, etc., so that navigation information (e.g., speed of the vehicle, a traveling direction, distance to a destination, a name of a current place, existence and a position of an object (i.e. a target object) in front of the vehicle, a sign such as a speed limit sign, information such as traffic backup information, etc.), which is needed for controlling the vehicle, becomes visible via a front windshield 50 (cf. FIG. 1) of the vehicle.
  • the front windshield 50 functions as a transparent/reflective member, which passes a part of incident light through and reflects at least a part of the remainder.
  • the following description mainly explains examples of an HUD device 100 mounted on a vehicle, or a car, which is provided with a front windshield 50.
  • the HUD device 100 is provided with: a light-scanning device 10, which includes a light source device 11, a light deflector 15 and a scanning mirror 20; a screen 30; and a concave mirror 40.
  • the HUD device 100 irradiates the front windshield 50 with light (i.e. imaging light) to form an image, such that a virtual image I becomes visible from a viewing point of a viewer A (i.e., in this example, a driver, who is an occupant of the car). That is to say, the viewer A can see an image (i.e., an intermediate image), which is formed (i.e., rendered) by the light-scanning device 10 on a screen, as a virtual image I via the front windshield 50.
  • a virtual image I i.e., an intermediate image
  • the HUD device 100 may be arranged beneath a dashboard of the car. Further, a distance from the viewing point of the viewer A and the front windshield 50 is from about several tens of centimeters to about a meter at most.
  • the concave mirror 40 is designed by means of existing optical-design simulation software, such that the concave mirror 40 has a predetermined amount of light condensing power, so as to form the virtual image I at a desired imaging position.
  • a setting is provided with respect to light condensing power of the concave mirror 40, such that the virtual image I is displayed at a position (i.e., a perspective position) of, for example, a meter or more to 30 meters or less (preferably 10 meters or less) away from the viewing point of the viewer A.
  • a front windshield is usually not flat but slightly curved. Therefore, the imaging position of the virtual image I is determined, based on the curved surfaces of the concave mirror 40 and the front windshield 50.
  • the light source device 11 synthesizes laser light in three colors, i.e., red (R), green (G) and blue (B), which are modulated in accordance with image data.
  • the synthesized light of the laser light in three colors is guided to the reflection surface of the light deflector 15.
  • the light deflector 15, which is provided as a deflection unit, is a two-axis microelectromechanical system (MEMS) scanner, which is manufactured in a semiconductor process, etc., and includes individual micro mirrors that can oscillate with respect to orthogonal two axes.
  • MEMS microelectromechanical system
  • Light i.e., synthesized light
  • image data which is output from the light source device 11
  • the light deflector 15 is deflected by the light deflector 15 and reflected by the scanning mirror 20, such that the screen 30 is irradiated.
  • the screen 30 is light-scanned, such that an intermediate image is formed on the screen 30.
  • an optical scanning system is configured with the light deflector 15 and the scanning mirror 20.
  • the concave mirror 40 is designed/arranged so as to correct elements of optical distortion caused by the front windshield 50, due to which a horizontal line of an intermediate image would become convex or concave.
  • a virtual image I which is an intermediate image that is magnified, is visible to the viewer A via the front windshield 50.
  • a magnified virtual image I is displayed on the front windshield 50 from the perspective of a viewer.
  • a transparent/reflective member there may be a combiner between the front windshield 50 and the viewing point of the viewer A, such that the combiner is irradiated with light from the concave mirror 40.
  • a virtual image can be displayed as well, similarly to the case with only the front windshield 50.
  • FIG. 2 is a block diagram illustrating a hardware configuration of a control system of the HUD device 100.
  • the control system of the HUD device 100 includes an FPGA 600, a central processing unit (CPU) 602, a read-only memory (ROM) 604, a random access memory (RAM) 606, an interface (I/F) 608, a bus line 610, a laser diode (LD) driver 6111 and a MEMS controller 615.
  • FPGA 600 central processing unit (CPU) 602
  • ROM read-only memory
  • RAM random access memory
  • I/F interface
  • bus line 610 a laser diode (LD) driver 6111
  • MEMS controller 615 a MEMS controller
  • the FPGA 600 operates an LD, which is explained in the following description, by means of the LD driver 6111 in accordance with image data. Further, the FPGA 600 operates the light deflector 15 by means of the MEMS controller 615.
  • the CPU 602 controls each function of the HUD device 100.
  • the ROM 604 stores a program for image processing, which is executed by the CPU 602 for controlling each function of the HUD device 100.
  • the RAM 606 is utilized as a work area of the CPU 602.
  • the I/F 608 is an interface for communication with an external controller, etc. For example, the I/F 608 may be connected to a controller area network (CAN) of a car, etc.
  • CAN controller area network
  • FIG. 3 is a block diagram illustrating functions of the HUD device 100.
  • the HUD device 100 is provided with a vehicle information input unit 800, an external information input unit 802, an image data generating unit 804 and an image rendering unit 806.
  • vehicle information input unit 800 information regarding a vehicle such as speed, traveling distance, a position of a target object or brightness of the surrounding environment is input via a CAN, etc.
  • external information input unit 802 information regarding outside of a vehicle such as navigation information from a car navigation system that is mounted on a car is input via an external network.
  • the image data generating unit 804 generates image data representing an image to be rendered, based on information that is input from the vehicle information input unit 800, the external information input unit 802, etc., and transmits the image data to the image rendering unit 806.
  • the image data generating unit 804 and the control unit 8060 are actualized by the FPGA 600.
  • the image rendering unit 806 is actualized by the LD driver 6111, the MEMS controller 615, the light-scanning device 10, the screen 30, the concave mirror 40, etc., in addition to the FPGA 600. Configuration of the Light Source Device
  • FIG. 4 is a drawing illustrating a configuration of the light source device 11.
  • the light source device 11 includes multiple (e.g., three) light emitting elements 111R, 111B and 111G, each of which is provided with a single or multiple luminous points.
  • Each of the light emitting elements is an LD, which emits luminous flux with mutually different wavelengths ⁇ R, ⁇ G, or ⁇ B.
  • ⁇ R equals to 640 nm
  • ⁇ G equals to 530 nm
  • ⁇ B equals to 445 nm.
  • the light emitting element 111R may be also represented as an LD 111R
  • the light emitting element 111G may be also represented as an LD 111G
  • the light emitting element 111B may be also represented as an LD 111B.
  • Each of the luminous flux with wavelength ⁇ R, ⁇ G or ⁇ B, which is emitted by the LD 111R, the LD 111G or the LD 111B, is coupled by a corresponding coupling lens 112R, 112G or 112B before entering into subsequent parts of the optical system.
  • the coupled luminous flux is reshaped by a corresponding aperture member 113R, 113G or 113B.
  • each aperture member may be in various shapes such as a round shape, an oval shape, a rectangular shape and a square shape, depending on divergence angle of luminous flux, etc.
  • a synthesizing element 115 is a dichroic mirror in a shape of a plate or a prism, which reflects or transmits luminous flux, depending on wavelengths, and synthesizes the luminous flux into a light path.
  • the synthesized luminous flux is guided by a lens 119 towards the reflection surface of the light deflector 15.
  • the lens 119 is a meniscus lens with a concave surface facing the light deflector 15.
  • FIG. 5 is a drawing illustrating a configuration of the light deflector 15.
  • the light deflector 15 is a two-axis MEMS scanner, which is manufactured in a semiconductor process.
  • the light deflector 15 includes: a mirror 150, which has a reflection surface; multiple beams, which are arranged in a direction of the ⁇ -axis; and a pair of serpentine parts 152, in which each pair of adjacent beams is connected via a turn-around part so as to be serpentine.
  • Each pair of adjacent beams in each serpentine part 152 is either beam A (152a) or beam B (152b), and is supported by a frame member 154.
  • Each of the multiple beams is individually provided with a piezoelectric member 156 (e.g., a piezoelectric transducer (PZT)).
  • PZT piezoelectric transducer
  • the pair of adjacent beams in each serpentine part are deflected in different directions.
  • the mirror 150 rotates at a large angle around the ⁇ -axis (i.e., in the vertical direction).
  • light-scanning is performed by use of resonance with a torsion bar, etc., that is connected to the mirror 150.
  • the HUD device 100 momentarily projects only a point image that corresponds to a diameter of a laser beam, an afterimage sufficiently remains to human eyes within a frame of an image because scanning is performed extremely quickly. Taking advantage of such an afterimage phenomenon, a viewer perceives as if an image were projected on a "display area". In reality, an image appearing on a screen is reflected by the concave mirror 40 and the front windshield 50, such that a viewer perceives a virtual image of the image on the "display area". Having the above-described mechanism, it is possible to stop emission of an LD, in a case of not displaying an image. In other words, in the "display area", luminance of a non-displaying area of a virtual image can be substantially 0.
  • imaging of a virtual image is performed by the HUD device 100 at an imaging position in a predetermined "display area", where imaging of the virtual image is possible.
  • the "display area” is determined as specified when designing the HUD device.
  • each emitting element of the light source device 11 is controlled by the FPGA 600 with respect to luminescence intensity, lighting timing and optical waveforms and is driven by the LD driver 6111 to emit light.
  • light that is emitted by each of the emitting elements and synthesized into a light path is deflected by the light deflector 15 with respect to two dimensions, based on rotation around the ⁇ -axis and rotation around the ⁇ -axis, and is intermediated by the scanning mirror 20 (cf. FIG. 1) so as to be emitted as scanning light towards the screen 30. That is to say, the screen 30 is scanned by the scanning light in two dimensions.
  • illustration of the scanning mirror 20 is omitted.
  • the scanning light performs oscillatory scanning (i.e., two-way back-and-forth scanning) in the main-scanning direction at a high-order frequency of approximately 20000 to 40000 Hz and at the same time performs one-way scanning in the sub-scanning direction at a low-order frequency of approximately several tens of Hz. That is to say, raster scanning is performed.
  • rendering per a pixel and displaying of a virtual image can be performed, by controlling emission of each emitting element in accordance with scanning position (i.e., position of the scanning light).
  • Time for rendering a screen, or scanning time (i.e., a cycle of two dimensional scanning) per a frame is several tens of milliseconds because, as described above, a sub-scanning cycle is several tens of Hz. For example, in a case where a main-scanning cycle is 20000 Hz and a sub-scanning cycle is 50 Hz, scanning time per a frame is 20 milliseconds.
  • the screen 30 includes: an image region 30a (i.e., a valid scanning region), on which an image is rendered (i.e., which is irradiated with light that is modulated in accordance with image data); and a frame region 30b, which encloses the image region.
  • an image region 30a i.e., a valid scanning region
  • an image i.e., which is irradiated with light that is modulated in accordance with image data
  • a frame region 30b which encloses the image region.
  • the entire range on which the light deflector 15 is capable of scanning is referred to as a "scanning range".
  • the scanning range is a range in combination of the image region 30a and a part (i.e., a part near the outer edge of the image region 30a) of the frame region 30b of the screen 30.
  • a trajectory of a scanning line in the scanning range is illustrated with a zig-zag line.
  • the number of scanning lines is fewer than in reality.
  • a synchronization detecting system 60 which includes a light receiving element, in the peripheral region (i.e., a part of the frame region 30b) near the image region 30a, which is within the scanning range.
  • the main-scanning direction of the screen 30 is taken to be the X-direction and the sub-scanning direction of the screen 30 is taken to be the Y-direction.
  • the synchronization detecting system 60 is placed in the positive Y side of the corner, which is in the negative X-direction and positive Y-direction of the image region.
  • the synchronization detecting system 60 detects operation of the light deflector 15, so as to output, to the FPGA 600, a synchronization signal for determining timing to start scanning and timing to finish scanning.
  • the image region 30a of the screen 30 is configured with a transparent element having a light diffusion effect such as a micro-lens array.
  • the image region is not required to be in a rectangular or flat shape and may be in a polygonal or round shape.
  • the screen 30 may be a flat or round plate without a light diffusion effect.
  • the image region may be a reflective element having a light diffusion effect such as a micro-mirror array, depending on device layouts.
  • the reference sign 852 is indicative of a micro-lens array.
  • the micro-lens array 852 has a micro convex lens configuration, which includes aligning micro convex lenses 851.
  • a luminous flux diameter 857 of a "pixel displaying beam", which is indicated by the reference sign 853, is smaller than the size of a micro convex lens 851.
  • the size 856 of the micro convex lens 851 is larger than the luminous flux diameter 857.
  • the pixel displaying beam 853 is a laser luminous flux with light intensity distribution in the form of Gaussian distribution around the center of the luminous flux.
  • the luminous flux diameter 857 is a radial directional distance of luminous flux that causes light intensity in the light intensity distribution to be decreased down to "1/e 2 ".
  • the luminous flux diameter 857 is illustrated to be the same size as the size 856 of the micro convex lens 851, the luminous flux diameter 857 is not required to be the same size as "the size 856 of the micro convex lens 851", but is only required not to be larger than the size 856 of the micro convex lens 851.
  • FIG. 8A the luminous flux diameter 857 is illustrated to be the same size as the size 856 of the micro convex lens 851, the luminous flux diameter 857 is not required to be the same size as "the size 856 of the micro convex lens 851", but is only required not to be larger than the size 856 of the micro convex lens 851.
  • the entirety of the pixel displaying beam 853 is incident to a micro convex lens 851 and is converted into diffused luminous flux 854 with a divergence angle 855.
  • the "divergence angle" may be referred to as a "diffusion angle” in the following description.
  • coherence noise does not occur because there is a single diffused luminous flux 854 without any other luminous flux to interfere with.
  • the size of the divergence angle 855 can be adjusted, as needed, with the shape of the micro convex lens 851.
  • a pixel displaying beam 811 has a luminous flux diameter that is twice as large as the alignment pitch 812 of micro convex lenses.
  • the pixel displaying beam 811 is incident across two micro convex lenses 813 and 814.
  • the pixel displaying beam 811 is diffused into two diffused luminous fluxes 815 and 816 because of the two micro convex lenses 813 and 814 to which the pixel displaying beam 811 is incident.
  • the two diffused luminous fluxes 815 and 816 overlap in a region 817, coherence noise occurs because of mutual interference in the region.
  • the coherence noise When the coherence noise enters eyes of a viewer, the coherence noise is perceived as speckles.
  • the luminous flux diameter (i.e., the luminous flux diameter of incident light) of the pixel displaying beam 811 is 100 ⁇ m
  • the alignment pitch 812 (i.e., the lens alignment pitch) of a micro convex lens 851 is chosen such that the luminous flux diameter of incident light is less than the lens alignment pitch (i.e., typically 110 ⁇ m, 150 ⁇ m or 200 ⁇ m)
  • the lens alignment pitch i.e., typically 110 ⁇ m, 150 ⁇ m or 200 ⁇ m
  • a micro convex lens 851 may be referred to as a "micro lens 851,” as appropriate.
  • a micro lens may be referred to as a "lens,” as appropriate.
  • Multiple micro lenses 851 constituting a micro-lens array 852 respectively
  • luminance of virtual images can be the highest, in a case of uniformly setting the amount of light of luminous flux (i.e., scanning light) for depicting an image on the micro-lens array to the maximum value with respect to each micro lens, i.e., in a case where light sources (e.g., LDs) are lighted at the maximum output power (i.e., the rated output power) during scanning of the micro-lens array.
  • luminous flux i.e., scanning light
  • luminance adjustment for virtual images can be performed mainly by decreasing light (by decreasing the amount of scanning light from the maximum value).
  • Luminous flux via the light deflector 15 scans the micro-lens array 852 two-dimensionally.
  • the longitudinal direction (i.e., X-direction) of the micro-lens array 852 is the main-scanning direction and the transverse direction (i.e., Y-direction) of the micro-lens array 852 is the sub-scanning direction
  • luminous flux is deflected at a high speed in the main-scanning direction and is deflected at a low speed in the sub-scanning direction.
  • two-way scanning is repeatedly performed on the micro-lens array 852, such that the light sources are lighted (are ON) on the first way 821 and the second way 822 in each two-way scanning.
  • the scanning line passes through each of the micro lenses 851 of the micro-lens array 852, and luminous flux that has passed through the micro lenses 851 becomes diffused luminous flux.
  • luminous flux that has passed through the micro lenses 851 becomes diffused luminous flux.
  • the person can see a point on each micro convex lens 851 because diffused luminous flux from the micro convex lens 851 reaches the person's eyes.
  • the person can perceive an image on the micro-lens array 852 because of the arrangement of as many points as the number of micro lenses 851.
  • each micro lens 851 is square in a plan view
  • the same discussion can be applied to lenses in any shape in planar view such as lenses in any quadrilateral shape in planar view, lenses in hexagonal shapes in planar views or lenses with different aspect ratios (i.e., horizontal to vertical ratios), as described below.
  • the control unit 8060 of the image rendering unit 806 generates a modulation signal for each light source (i.e., each color), based on image data obtained from the image data generating unit 804. Further, the control unit 8060 outputs the modulation signal to the LD driver 6111, so as to modulate emission intensity of each light source at a high speed.
  • the higher the frequency of modulation, or modulation frequency (hereinafter also referred to as "clock frequency"), the more finely a pattern can be rendered on the micro-lens array 852.
  • the minimum rendering width 832 (i.e., the distance between the centers of two adjacent points 831) between points 831, which are rendered at an instant, is determined in accordance with a relation between clock frequency and a speed of rendering in the scanning line.
  • a light source is turned on when a modulation signal is at high level (1) and is turned off when the modulation signal is at low level (0).
  • intensity for each light source (i.e., each color) according to a modulation signal is dependent on a proportion of each color (i.e., red, green or blue) represented by color information for each pixel of image data.
  • a point rendered (i.e., formed) on the micro-lens array 852 with luminous flux emitted by a light source when the modulation signal is at a high level is referred to as a "rendered point".
  • a “rendered point” may be also referred to as a "beam spot”.
  • the pixel displaying beam 853 has an intensity profile with Gaussian distribution, which is generally unique to laser light. Therefore, the intensity is high at the center of luminous flux and becomes lower with increasing distance from the center.
  • the following description is for considering a case of observing a pixel displaying beam 853, which has passed through the micro lens 851, squarely from the micro lens 851.
  • intensity of a point on the micro lens 851 is high because the center of the micro lens 851 approximately matches the center of the incident luminous flux.
  • intensity of a point on the micro lens 851 is low because the center of the micro lens 851 and the center of the incident flux are misaligned, which means that the luminous flux that passes through the center of the micro lens 851 has intensity of the edge of Gaussian distribution.
  • intensity of a point on the micro lens 851 is lower in the case of B, compared to the case of A.
  • intensity of a point on the micro lens 851 becomes lower as the center of luminous flux that is incident to the micro lens 851 is further deviated from the center of the micro lens 851.
  • intensity distribution of points formed upon scanning on the micro-lens array with reference to FIG. 12.
  • intensity distribution of points formed in a row i.e., a row of lenses constituted by multiple micro lenses 851 aligning in the main-scanning direction, or a row of lenses corresponding to the first way 821) of the main-scanning direction of the micro-lens array.
  • the following description explains intensity distribution of points formed in a case of lighting a light source repeatedly in an output pattern including at least one high output power mode (e.g., a mode for lighting the light sources at the maximum output power) and at least one low output power mode (e.g., a mode for lighting the light sources at output power that is lower than the maximum output power) during scanning of the micro-lens array.
  • the "high output power mode” is indicative of a mode for lighting a light source at a relatively high output power
  • the "low output power mode” is indicative of a mode for lighting a light source at a relatively low (i.e., lower than the high output power) output power. Therefore, the "high output power mode” may be a mode for lighting a light source at an output power that is lower than the maximum output power.
  • the output level of each light source i.e., each color
  • the output level of each color of RGB in a pixel A is as follows.
  • Output level of each color of pixel A pixel data of corresponding color of pixel A ⁇ output mode (e.g., high output mode or low output mode)
  • output mode e.g., high output mode or low output mode
  • a light source is lighted repeatedly in an output pattern that includes at least one high output power mode and at least one low output power mode, so as to depict multiple rendered points 873, which are illustrated in FIG. 12, alternately in the high output power mode and in the low output power mode.
  • a rendered point i.e., a white rendered point in FIG. 13
  • a rendered point i.e., a black rendered point in FIG. 13
  • a rendered point i.e., a black rendered point in FIG. 13
  • a rendered point rendered in a high output power mode may be also referred to as a "high power rendered point”
  • a rendered point rendered in a low output power mode may be also referred to as a "low power rendered point”.
  • high power rendered points and low power rendered points partially overlap.
  • a means for making the pitch of high power rendered points narrower than the alignment pitch of micro lenses in the main-scanning direction is provided in terms of a scanning condition and alignment of lenses. Accordingly, at least one high power rendered point is formed on each micro lens. Therefore, it is possible to prevent unevenness in an amount of light with respect to each micro lens. Consequently, it is possible to prevent luminance unevenness on an entire image.
  • the "decreased lighting” is indicative of repeatedly lighting a light source in an output pattern in which a low output power mode is replaced with an off-light mode (i.e., a mode for turning off a light source), or an output pattern including at least one high output power mode (i.e., lighting mode) and at least one off-light mode.
  • an off-light mode i.e., a mode for turning off a light source
  • an output pattern including at least one high output power mode i.e., lighting mode
  • FIG. 14 an example of repeatedly lighting a light source in an output pattern including at least one high output power mode and at least one off-light mode is illustrated.
  • small white dots with a reference sign 874 are indicative of timings for executing off-light mode, which are hereinafter also referred to as "zero-power points" for the sake of convenience.
  • the number of rendered points in total when rendering in the output pattern of FIG. 14 is a half of the number of rendered points in total when rendering in the output pattern of FIG. 13. Therefore, in the pattern of FIG. 14, luminance of virtual images is reduced, compared to the output pattern of FIG. 13. That is to say, it is possible to increase a light reduction rate (i.e., a luminance reduction rate) by executing an off-light mode instead of a low output power mode.
  • a light reduction rate i.e., a luminance reduction rate
  • the rendered point pitch is sufficiently narrow (e.g., in a case where the distance between micro lenses in the main-scanning direction is wider than the rendered point pitch)
  • at least one rendered point is formed on each micro lens. Therefore, it is possible to prevent intensity of points from fluctuating as explained with reference to FIG. 11. That is, if the high output mode and the off-light mode are alternated at least once while one micro lens is being scanned, at least one rendered point is formed for each micro lens. Accordingly, it is possible to prevent luminance unevenness of an image from occurrring.
  • FIGS. 15A through 15F the following description explains specific examples of output patterns with luminance reduction rates that are different from each other.
  • FIGS. 15A through 15F six types of aligning rendered points and six types of modulation signals, which respectively correspond to six output patterns with luminance reduction rates that are different from each other, are illustrated.
  • the output power level in a high output power mode is the maximum output power and that the output power level in a low output power mode is the same in each of the output patterns.
  • the luminance reduction rate from the maximum luminance (i.e., luminance when continuously lighting a light source at the maximum output power; the same applies hereinafter) up to approximately 50 %, by alternately arranging high power rendered points and low power rendered points, i.e., by repeatedly lighting a light source in an output pattern constituted by one high output power mode and one low output power mode.
  • the luminance reduction rate from the maximum luminance to 50 %, by alternately arranging high power rendered points and zero-power points, i.e., by repeatedly lighting a light source in an output pattern constituted by one high output power mode and one off-light mode.
  • the luminance reduction rate from the maximum luminance up to approximately 66 %, by repeatedly arranging one high power rendered point followed by two low power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one high output power mode and two low output power modes in series.
  • the luminance reduction rate from the maximum luminance is set to approximately 66 %, by repeatedly arranging one high power rendered point followed by two zero-power points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one high output power mode and two off-light modes in series.
  • the luminance reduction rate from the maximum luminance up to approximately 75 %, by repeatedly arranging one high power rendered point followed by three low power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one high output power mode and three low output power modes in series.
  • the luminance reduction rate from the maximum luminance to 75 %, by repeatedly arranging one high power rendered point followed by three zero-power points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one high output power mode and three off-light modes in series.
  • an output pattern constituted by multiple high output power modes in series and one low output power mode or multiple low output power modes (or off-light modes) in series as well (see FIGS. 22A through 22D).
  • the luminance reduction rate from the maximum luminance up to approximately 50 %, by arranging two high power rendered points in series and two low power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by two high output power modes in series and two low output power modes in series.
  • the luminance reduction rate from the maximum luminance is set to 50 %, by arranging two high power rendered points in series followed by two zero-power points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by two high output power modes in series and two off-light modes in series.
  • the luminance reduction rate from the maximum luminance up to approximately 25 %, by arranging one low power rendered point followed by three high power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one low output power mode and three high output power modes in series.
  • the luminance reduction rate from the maximum luminance is set to 25 %, by arranging one zero-power point followed by three high power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one off-light mode and three high output power modes in series.
  • an output pattern constituted in combination of a high output power mode, a low output power mode and a light-out mode as well.
  • the luminance reduction rate from the maximum luminance up to approximately 68 %, by arranging one high power rendered point, one low power rendered point and one zero-power point in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one high output power mode, one low output power mode and one off-light mode.
  • an output pattern constituted in combination of a low output power mode and an off-light mode as well.
  • the luminance reduction rate from the maximum luminance up to approximately 99 %, by alternately arranging a zero-power point and a low power rendered point, i.e., by repeatedly lighting a light source in an output pattern constituted by one off-light mode and one low output power mode.
  • the luminance reduction rate from the maximum luminance up to approximately 33 %, by arranging two high power rendered points in series and one low power rendered point, i.e., by repeatedly lighting a light source in an output pattern constituted by two high output power modes in series and one low output power mode.
  • the luminance reduction rate from the maximum luminance up to approximately 25 %, by arranging three high power rendered points in series and one low power rendered point, i.e., by repeatedly lighting a light source in an output pattern constituted by three high output power modes in series and one low output power mode.
  • the luminance reduction rate from the maximum luminance up to approximately 40 %, by arranging three high power rendered points in series and two low power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by three high output power modes in series and two low output power modes in series.
  • the luminance reduction rate from the maximum luminance up to approximately 40 %, by arranging one low power rendered point, one high power rendered point, one low power rendered point, and two high power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by one low output power mode, one high output power mode, one low output power mode, and two high output power modes in series.
  • the luminance reduction rate (the ratio of the number of high power rendered points in the output pattern to the number of low power rendered points) is the same as in the case of FIG. 23C, but the arrangements of the high power rendered points and the low power rendered points in the output pattern differ.
  • the luminance reduction rate from the maximum luminance up to approximately 60 %, by arranging three low power rendered points in series and two high power rendered points in series, i.e., by repeatedly lighting a light source in an output pattern constituted by three high output power modes in series and two low output power modes in series.
  • the luminance reduction rate from the maximum luminance up to approximately 60 %, by arranging one low power rendered point, one high power rendered point, two low power rendered points in series, and one high power rendered point, i.e., by repeatedly lighting a light source in an output pattern constituted by one low output power mode, one high output power mode, two high output power modes in series, and one low output power mode.
  • the luminance reduction rate (the ratio of the number of high power rendered points in the output pattern to the number of low power rendered points) is the same as in the case of FIG. 23E, but the arrangements of the high power rendered points and the low power rendered points in the output pattern differ.
  • FIGS. 15A through 15F and FIGS. 22A through 22F there may be multiple output patterns based on each of the output patterns as illustrated in FIGS. 15A through 15F and FIGS. 22A through 22F, whose output power levels of at least one of the high output power mode and the low output power mode are different from each other.
  • each output pattern i.e., an output pattern as a unit
  • each output pattern corresponds to one pixel, or one micro lens.
  • an output pattern for a desired luminance reduction rate can be obtained by combination of at least two of a high output power mode, a low output power mode and an off-light mode, as appropriate.
  • the "decrease cycle” may be indicative of a lighting cycle (i.e., a cycle of a lighting mode), an off-light cycle (i.e., a cycle of an off-light mode), a rendered point pitch (i.e., the distance between the centers of adjacent rendered points in the main-scanning direction) or a zero-power point pitch (i.e., the distance between the centers of adjacent zero-power points in the main-scanning direction).
  • luminance unevenness on an image becomes more likely to occur with increase in a width of a dark area 874 (i.e., a zero-power point) between rendered points 873.
  • a partial luminance reduction occurs and a moire pattern as a whole is likely to be visually observed at a position where at least one rendered point is not formed on the micro lens, and a beam spot is irradiated to the boundary portion between the micro lenses.
  • the decrease cycle is originally as wide as one lens, the cycle is enlarged into a long-period pattern that is as wide as several or several tens of lenses, which is easily perceived by human eyes, due to moire. Consequently, visibility of an image is decreased.
  • a light source such that at least one rendered point is formed on each micro lens during scanning of a micro-lens array.
  • the following description explains a relation between the diameter (i.e., the beam spot diameter) of luminous flux incident to a lens and the rendered point pitch (i.e., the beam spot pitch in the main-scanning direction), with reference to FIGS. 17A and 17B.
  • Luminance unevenness associated with reduction of light changes, depending on the diameter of incident luminous flux. Luminance unevenness is prevented more with increase in the diameter of the incident luminous flux.
  • the diameter of incident luminous flux is defined to be the diameter (hereinafter also referred to as an "effective diameter") having intensity that is 1/e 2 of the peak intensity of the luminous flux.
  • FIG. 17B a result of numerical calculation for a relation between a ratio of the effective diameter to the distance between adjacent high power rendered points (the distance between centers of the adjacent high power rendered points) and luminance unevenness is illustrated. It is clear from FIG. 17B that, in order to make luminance unevenness that occurs to equal to or lower than a half of the peak intensity, the diameter (i.e., the effective diameter) of incident luminous flux needs to be equal to or higher than 1.2 times as wide as the distance between the adjacent high power rendered points. In the above way, luminance unevenness can be at an acceptable level.
  • the light source device 11' is provided with: three LDs (i.e., LD1 through LD3) as light sources; coupling lenses CL1 through CL3 for coupling light emitted by the LD1 through LD3, respectively; aperture members AP1 through AP3 for reshaping the light that has traveled through the coupling lenses CL1 through CL3, respectively; a mirror M for reflecting the light that has reshaped by the aperture member AP1; a prism Q1 as a light path synthesizing element, which is arranged on the light path of the light that has been reflected by the mirror M and the light that has been reshaped by the aperture member AP2; a prism Q2 as a light path synthesizing element, which is arranged on the light path of the light that has traveled through the prism Q1 and the light that has been reshaped by the aperture member AP3; a prism Q3 for branching the light that has traveled through the prism Q2 into transmitted light and reflected light; a lens
  • wavelength and an amount of light from a light source change, depending on temperature. Therefore, luminance or color generated under a predetermined temperature cannot be steadily maintained.
  • the branching element i.e., the prism Q3, in the above case
  • one of the branched light is guided to the light deflector 15 and the other of the branched light is guided to the light receiving element (i.e., the PD, in the above case), so as to monitor the amount of light at a given moment.
  • monitoring of an amount of light from each light source is performed by lighting each light source in a sequential order while an image is not being rendered on the screen 30, i.e., while the frame region 30b is being scanned or at an interspace between continuing frames.
  • a high output power mode and a low output power mode are periodically repeated even at a time of causing light flux to be incident to the PD, similarly to the time of generating rendering light (i.e., scanning light), so as to accurately detect an amount of light during an operation mode at a given moment (i.e., a high output power mode or a low output power mode). Consequently, even when reducing light at a time of rendering an image, it becomes less possible that shift in luminance or color shift occurs.
  • a phototransistor an avalanche photodiode (APD), etc.
  • APD avalanche photodiode
  • the present invention can be applied to a micro-lens array in which hexagonal lenses in planar views are aligned in a honeycomb structure, as illustrated in FIGS. 19B and 19C, and to a micro-lens array including lenses as illustrated in FIGS. 19A, 19B and 19C whose aspect ratios are changed, respectively, as illustrated in FIGS. 19D, 19E and 19F.
  • the width of the lens in the sub-scanning direction is narrower. Specifically, it is preferable that the width of each lens in the sub-scanning direction is narrower than the width of the lens in the main-scanning direction. In the above way, the light reduction rate can be increased while preventing occurrence of luminance unevenness.
  • control unit 8060 of the image rendering unit 806, which is provided in the HUD device 100 according to the present embodiment, with reference to FIG. 20.
  • the control unit 8060 includes an output pattern selecting unit 8060a and a modulation signal generating unit 8060b, as illustrated in FIG. 20.
  • the brightest range corresponds to the output pattern P0
  • the darkest range e.g., a range envisioned for a road at night or in a tunnel
  • the ten brightness ranges correspond to the ten output patterns, respectively, in the order of brightness.
  • light reduction rates of the output patterns with respect to the maximum luminance are 10 % in P1, 20 % in P2, 30 % in P3, 40 % in P4, 50 % in P5, 60 % in P6, 70 % in P7, 80 % in P8 and 90 % in P9.
  • the number of the output patterns and brightness ranges is not limited to the above (i.e., ten, respectively). The point is that the number should be at least two, respectively.
  • the output pattern selecting unit 8060a obtains brightness information around the vehicle from the vehicle information input unit 800, refers to the above-described table stored in the storing unit 605, selects an output pattern corresponding to the brightness information that is obtained out of the ten output patterns, and transmits the selected output pattern to the modulation signal generating unit 8060b.
  • the vehicle information input unit 800 obtains brightness information around the vehicle from a luminance sensor, etc., which is provided on the vehicle, etc.
  • the modulation signal generating unit 8060b generates a modulation signal for each light source (i.e., each color), based on image data from the image data generating unit 804 and an output pattern from the output pattern selecting unit 8060a and outputs the modulation signal to the LD driver 6111.
  • the modulation signal for each color is generated by multiplying a proportion of each color represented by color information for each pixel of the image data with the output power levels of a high output power mode and a low output power mode included in the output pattern.
  • the LD driver 6111 applies driving current, which has a current value corresponding to intensity according to each modulation signal and has the same frequency as the modulation signal, to a corresponding light source, so as to light the light source.
  • FIG. 21 corresponds to a processing algorithm that is executed by the control unit 8060.
  • the modulation signal generating unit 8060b obtains image data from the image data generating unit 804. Note that the image data generating unit 804 starts generating image data when an electric system of a vehicle, on which the HUD device 100 is mounted, is turned on.
  • the output pattern selecting unit 8060a obtains brightness information around the vehicle from the vehicle information input unit 800.
  • the output pattern selecting unit 8060a selects an output pattern, based on the obtained brightness information. Specifically, referring to the above-described table, which is stored in the storing unit 605, an output pattern that corresponds to the obtained brightness information is selected and transmitted to the modulation signal generating unit 8060b.
  • the modulation signal generating unit 8060b generates a modulation signal for each light source, by use of the obtained image data and the output pattern that has been received.
  • each light source is driven.
  • the modulation signal generating unit 8060b outputs a modulation signal generated for each light source to the LD driver 6111, for driving each light source.
  • a pulse light with intensity in accordance with image data and with an output pattern is emitted from each light source in a synchronized manner. Consequently, a color virtual image with desired resolution (i.e., a specified value according to device specifications) and brightness is displayed in the display area.
  • Step S6 whether or not to terminate the process is determined. Specifically, when the electric system of the vehicle, on which the HUD device 100 is mounted, is turned from on to off, the process is terminated to end the flow. When the electric system of the vehicle, on which the HUD device 100 is mounted, remains being on, the process is continued and returned back to Step S1.
  • Step S1 may be performed after performing Steps S2 and S3.
  • the HUD device 100 is, from a first viewpoint, a display device for scanning with light emitted by a light source (e.g., an LD) an optical element array (e.g., a micro lens array) including multiple optical elements (e.g., micro lenses) to form an image and for projecting the light that has formed the image.
  • the display device includes a control unit 8060 that is capable of changing output power of the light source while each of the multiple optical elements is being scanned.
  • “capable of changing output power of the light source” includes decreasing of the output power of the light source to 0 and increasing of the output power of the light source from 0 in the changing.
  • a term "image" is utilized to additionally include a virtual image, as appropriate.
  • the HUD device 100 is, from a second viewpoint, a display device including: a light source (i.e., an LD); a light deflector 15 configured to deflect light emitted by the light source; an optical element array (e.g., a micro lens array) including multiple optical elements (e.g., micro lenses), which is scanned with the light via the light deflector 15; a light projecting unit (e.g., a concave mirror 40) configured to project the light that has traveled through the optical element array; and a control unit 8060 that is capable of changing output power of the light source while each of the multiple optical elements is being scanned with the light via the light deflector 15.
  • a light source i.e., an LD
  • a light deflector 15 configured to deflect light emitted by the light source
  • an optical element array e.g., a micro lens array
  • multiple optical elements e.g., micro lenses
  • a light projecting unit e.g., a conca
  • the HUD device 100 By use of the HUD device 100 according to the present embodiment, it is possible to change output power of a light source while each optical element is being scanned. That is, it is possible to change the output power of a light source while one optical element is being scanned. Therefore, it is possible to adjust luminance of an image while controlling against luminance unevenness of the image from occurring.
  • control unit 8060 executes each of a high output power mode and a low output power mode at least once while each of the multiple optical elements is being scanned, so as to change the output power of the light source while each of the plurality of optical elements is being scanned.
  • the high output power mode relatively increases the output power of the light source.
  • the low output power mode relatively decreases the output power of the light source.
  • a distance between centers of two adjacent beam spots, which are included in beam spots formed side-by-side in a scanning direction on the optical element array during the high output power mode is narrower than a width of each of the plurality of optical elements in the scanning direction.
  • At least one beam spot is formed on each of the multiple optical elements during the high output power mode.
  • control unit 8060 repeatedly executes an output pattern including each of the high output power mode and the low output power mode at least once. In this case, control is simplified.
  • the output pattern includes each of the high output power mode and the low output power mode once. In this case, control is extremely simplified.
  • the output pattern includes the high output power mode once and includes the low output power mode multiple times. In this case, it is possible to increase the light reduction rate.
  • control unit 8060 obtains brightness information about the surrounding environment and repeatedly executes one of the multiple output patterns in accordance with the brightness information that has been obtained.
  • the control unit 8060 obtains brightness information about the surrounding environment and repeatedly executes one of the multiple output patterns in accordance with the brightness information that has been obtained.
  • luminance of an image is higher as brightness of the surrounding environment is brighter. Consequently, it is possible to display a virtual image with high visibility, regardless of brightness of environment surrounding a vehicle, on which the HUD device 100 is mounted.
  • the HUD device 100 further includes a light amount detecting unit for detecting an amount of light from a light source. Further, it is preferable that the light amount detecting unit detects the amount of light in a cycle that is as long as an integer (value) times a cycle for repeating an output pattern.
  • an output pattern is executed m times for scanning the screen 30 once (i.e., for depicting an image of a frame)
  • the low output power mode is a mode for turning the output power of the light source to 0. That is to say, it is possible that the low output power mode is interpreted to include an off-light mode, in a broad sense. In a case where there are a low output power mode and an off-light mode, the high output power mode may be referred to as a lighting mode, in a broad sense.
  • control unit 8060 controls a timing of lighting a light source such that multiple beam spots are aligned in the scanning direction on each optical element, so as to change output power of the light source while each optical element is being scanned.
  • one of the multiple beam spots partially overlaps with another one or more of the beam spots and that an overlapped area of the one of the beam spots and the one or more of the beam spots is located at the optical center of an optical element.
  • multiple overlapped areas of beam spots are located at the optical center of the optical element. More specifically, it is preferable that an overlapped area of at least one high power rendered point, or at least one low power rendered point, an overlapped area of multiple high power rendered points and an overlapped area of multiple low power rendered areas are located at the optical center of the optical element. In this case, it is possible to prevent luminance unevenness of each pixel.
  • a single one (i.e., a high power rendered point or a low power rendered point) of the multiple beam spots is located at the optical center of each of the optical elements.
  • control unit 8060 controls the timing of lighting a light source such that a single beam spot (i.e., a high power rendered point or a low power rendered point) is located at each optical element, so as to change output power of the light source while each optical element is being scanned.
  • a single beam spot i.e., a high power rendered point or a low power rendered point
  • a single beam spot i.e., a high power rendered point or a low power rendered point
  • the optical center of the optical element is located nearby the center of the single beam spot.
  • control unit 8060 controls the timing of lighting a light source so as to minimize a difference, in center-to-center distance in a distance of beam spots adjacent in the main-scanning direction, of the central area (hereinafter also referred to as a "main-scanning central area”) with the edge areas (hereinafter also referred to as a "main-scanning edge areas”) of the optical element array in the main-scanning direction.
  • control unit 8060 controls the timing of lighting a light source so as to minimize a difference, of a central area with edge areas of the optical element array in the scanning direction, with respect to in center-to-center distance of beam spots adjacent in the scanning direction.
  • the effective diameter (i.e., 1/e 2 ) of each beam spot in the scanning direction is more than 1.2 times wider than a distance between centers of beam spots adjacent in the scanning direction. In this case, it is possible to reduce moire and noise of an image, as deviation of luminance at the micro level is reduced. It is preferable that the beam spots adjacent in the scanning direction are high power rendered points.
  • a width of an optical element in the main-scanning direction is wider than a width of the optical element in the sub-scanning direction (i.e., a direction orthogonal to the main-scanning direction).
  • multiple rendered points or multiple points including at least one rendered point and at least one zero-power point can be easily formed on each optical element. That is to say, freedom of choice for clock frequency (i.e., modulation frequency) to drive a light source is enhanced.
  • the HUD device 100 is, from a third viewpoint, a display device for scanning with light emitted by a light source an optical element array including multiple optical elements to form an image and for projecting the light that has formed the image.
  • the display device includes a control unit that is capable of turning on and off the light source while each of the multiple optical elements is being scanned.
  • a vehicle apparatus including an HUD device 100 according to the present embodiment and a vehicle (i.e., an object), on which the HUD device 100 is mounted, it is possible to provide useful information to a driver (i.e., viewer) with high visibility, regardless of change in traveling environment of a vehicle (e.g., change in climate, change between day and night, when getting in or out of a structure).
  • a display method is a display method for scanning with scanning light an optical element array including multiple optical elements and for projecting light that has traveled through the optical element array to display an image.
  • the display method includes changing an amount of the scanning light while each of the multiple optical elements is being scanned with the scanning light. Note that "changing an amount of the scanning light” includes decreasing the amount of the scanning light to 0 and increasing the amount of the scanning light from 0.
  • the display method according to the present embodiment it is possible to adjust luminance of an image while controlling against luminance unevenness of the image from occurring, as an amount of scanning light is changed while each optical element is being scanned, that is, as an amount of scanning light is changed during the scanning of one optical element.
  • micro-lens array including multiple micro lenses as optical elements
  • same discussion can be applied to a case of employing a micro-mirror array including multiple micro mirrors as optical elements, instead of a micro-lens array.
  • the HUD device 100 is provided with a flat screen 30, it is possible to employ a curved screen that is convex on the outgoing surface along the main-scanning direction, for example.
  • a curved screen that is convex on the outgoing surface along the main-scanning direction, for example.
  • the optical system in the HUD device is configured with the concave mirror 40 (i.e., a concave mirror), there is no such limitation.
  • the optical system may be configured with a convex mirror and may be configured with a curved mirror (i.e., a concave or convex mirror) and a turning mirror, which is arranged between the curved mirror and the screen 30.
  • an LD i.e., an edge emitting laser
  • another type of laser such as a surface emitting laser may be employed.
  • the HUD device in the above-described embodiment is configured to accommodate color images
  • the HUD device may be configured to accommodate monochrome images.
  • the transreflective member is not limited to a front windshield of a vehicle, and may be a side windshield or rear windshield, for example. That is to say, it is preferable that the transreflective member is provided on a vehicle, where a viewer who views a virtual image is aboard, and the transreflective member is a window member (such as a windshield) for the viewer to view the outside of the vehicle.
  • the explanation in the above-described embodiment is provided with an example of an HUD device mounted on a car, etc.
  • the point is that the HUD device is mounted on a movable object such as a vehicle, an aircraft, a vessel or a robot.
  • a vehicle used as an "object apparatus" in the present invention is not limited to a four-wheeled car, and may be a motorcycle, a motor tricycle, etc. In the above cases, it is required to be equipped with a windshield or a combiner as a transreflective member.
  • a power source of a vehicle may be an engine, a motor or combination of an engine and a motor, etc.
  • the display device according to the present invention is applied to a device for displaying an image (including a virtual image) such as a projector, a prompter or a head-mounted display, not being limited to an HUD device.
  • the display device may be one that is attached to or mounted on an object such as a moving object, a human body or a motionless object (including an object that is conveyable and an object that is permanently equipped), and may be one that is used independently.
  • an object such as a moving object, a human body or a motionless object (including an object that is conveyable and an object that is permanently equipped), and may be one that is used independently.
  • the optical system of the HUD device 100 it is possible to use the optical system of the HUD device 100. Specifically, it is possible to directly project light, which has been emitted from a light source device 11 via a light deflector 15 and a screen 30, to a projected object such as a projection screen, a table, a floor or a ceiling. Further, it is possible to project the light, after traveling through the screen 30, to a projected object as described above via a lens or a mirror.
  • a control method for decreasing pixels such that some of the pixels constituting image data are not displayed in accordance with a predetermined rule, for a purpose of adjusting luminance, or especially for a purpose of reducing light (see PLT 1, for example).
  • the inventors proceeded to propose the invention of the above-described embodiment to actualize an HUD device that is capable of adjusting luminance of an image while controlling against luminance unevenness of the image from occurring.
  • light deflector 30 screen i.e., member including an optical element array
  • concave mirror i.e., light projecting unit
  • front windshield transparent/reflective member
  • HUD device i.e., display device
  • 111R, 111G, 111B light emitting element i.e., light source

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  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
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  • Signal Processing (AREA)
  • Optics & Photonics (AREA)
  • Computer Hardware Design (AREA)
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Abstract

L'invention concerne un dispositif d'affichage tête haute comprenant un dispositif d'affichage destiné à balayer, avec la lumière émise par une source de lumière (par exemple une LD), un réseau d'éléments optiques (par exemple un réseau de microlentilles) comprenant de multiples éléments optiques (par exemple des microlentilles) afin de former une image et pour projeter la lumière qui a formé l'image. Le dispositif d'affichage comprend une unité de commande (8060) qui est capable de modifier la puissance de sortie de la lumière. Il est ainsi possible de réaliser un dispositif d'affichage qui est capable de régler la luminance d'une image tout en régulant celle-ci afin de prévenir l'apparition d'une luminance irrégulière de l'image.
PCT/JP2018/009713 2017-03-15 2018-03-13 Dispositif d'affichage à balayage laser avec réglage de la luminance WO2018168846A1 (fr)

Priority Applications (2)

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US16/486,929 US10950152B2 (en) 2017-03-15 2018-03-13 Laser scanning display with luminance adjustment
EP18715989.2A EP3596529A1 (fr) 2017-03-15 2018-03-13 Dispositif d'affichage à balayage laser avec réglage de la luminance

Applications Claiming Priority (4)

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JP2017049274 2017-03-15
JP2017-049274 2017-03-15
JP2018-006229 2018-01-18
JP2018006229A JP2018156062A (ja) 2017-03-15 2018-01-18 表示装置、物体装置及び表示方法

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WO2020233492A1 (fr) * 2019-05-17 2020-11-26 未来（北京）黑科技有限公司 Dispositif d'affichage, affichage tête haute et véhicule à moteur

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JP2014132286A (ja) 2013-01-04 2014-07-17 Jvc Kenwood Corp 画像表示装置
US20150062345A1 (en) * 2013-08-30 2015-03-05 Masato KUSANAGI Image generation apparatus, vehicle, control method of image generation apparatus and storage medium
JP2017049274A (ja) 2015-08-31 2017-03-09 株式会社Ｎｓｃ ディスプレイ装置
JP2018006229A (ja) 2016-07-06 2018-01-11 パナソニックＩｐマネジメント株式会社 電解質膜及び燃料電池

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WO2020233492A1 (fr) * 2019-05-17 2020-11-26 未来（北京）黑科技有限公司 Dispositif d'affichage, affichage tête haute et véhicule à moteur
US11860360B2 (en) 2019-05-17 2024-01-02 Futurus Technology Co., Ltd. Display apparatus, head-up display and motor vehicle

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