WO2014136208A1

WO2014136208A1 - Lighting optical system and projection display apparatus

Info

Publication number: WO2014136208A1
Application number: PCT/JP2013/056007
Authority: WO
Inventors: 明弘大坂
Original assignee: Ｎｅｃディスプレイソリューションズ株式会社
Priority date: 2013-03-05
Filing date: 2013-03-05
Publication date: 2014-09-12

Abstract

One purpose of the present invention is to provide a versatile lighting optical system capable of outputting a plurality of kinds of fluorescence at arbitrary timing. The lighting optical system has a color wheel (20), and a plurality of light sources. The color wheel has a substrate (2), which can rotate about a rotation axis, and a plurality of fluorescent material layers (11, 12, 13), which are formed substantially in concentric annular shapes on one surface of the substrate with a rotating axis at the center, and which respectively emit fluorescence having wavelengths different from each other when irradiated with excitation light. The light sources are provided corresponding to the fluorescent material layers, respectively, and radiate the excitation light to the fluorescent material layers, respectively.

Description

Illumination optical system and projection display device

The present invention relates to an illumination optical system including a phosphor that emits fluorescence when irradiated with excitation light, and a projection display device including the illumination optical system.

Recently, a light source device (illumination optical system) using light emitted from a phosphor by irradiating the phosphor with excitation light has been developed. Japanese Unexamined Patent Publication No. 2009-277516 (hereinafter referred to as Patent Document 1) and Japanese Unexamined Patent Application Publication No. 2011-13313 (hereinafter referred to as Patent Document 2) disclose a projection display provided with such an illumination optical system. An apparatus is disclosed.

The illumination optical systems described in Patent Document 1 and Patent Document 2 include a fluorescent wheel having a phosphor layer. The fluorescent wheel is rotatable around a rotation axis, and a phosphor layer is formed in an annular shape around the rotation axis. The light source device includes a light source that irradiates the phosphor layer of the fluorescent wheel with excitation light. The phosphor layer emits fluorescence when irradiated with excitation light from the light source device. In order to suppress the deterioration of the phosphor due to heat generated by the excitation light irradiation, the phosphor wheel is rotated around the rotation axis while the phosphor layer is irradiated with the excitation light.

Depending on the application of the illumination optical system, it may be required to emit fluorescence of different colors sequentially in time. In this case, as shown in FIG. 1, a plurality of

phosphor layers

61, 62, 63 that emit fluorescence of different colors along the rotation direction R of the phosphor wheel 60 are formed on the substrate 2. For example, the first phosphor layer 61 is a phosphor that emits red fluorescence, the second phosphor layer 62 is a phosphor that emits green fluorescence, and the third phosphor layer 63 emits blue fluorescence. It is a phosphor that emits light. Specifically, the plurality of

phosphor layers

61, 62, 63 are provided side by side in the circumferential direction around the rotation axis 10.

Excitation light from the light source is applied to a point 64 on the phosphor wheel 60. By rotating the substrate 2 together with the irradiation of the excitation light, the locus 67 of the irradiation spot 64 is drawn on the plurality of

phosphor layers

61, 62, 63. Thereby, the light from different

fluorescent substance layers

61, 62, and 63 is emitted in order.

However, such a phosphor wheel 60 cannot continuously emit the same light emitted from the same phosphor layer. Further, the emission time of the fluorescence emitted from each phosphor layer is determined by the size of the region where each phosphor layer is formed. Therefore, the ratio of the emission time of the fluorescence emitted from one phosphor layer 61 and the emission time of the fluorescence emitted from the

other phosphor layers

62 and 63 is constant and cannot be changed.

Also, depending on the use of the illumination optical system, it may be required to emit light of the same color continuously. In this case, as shown in FIG. 2, a single phosphor layer 71 is provided on the circumference along the rotation direction R of the phosphor wheel 70. Excitation light from the light source is applied to a point 64 on the phosphor wheel 70. In order to suppress deterioration of excitation light due to heat generation, the phosphor layer 71 is irradiated with excitation light while rotating the phosphor wheel 70. Thereby, the locus 65 of the irradiation spot 64 is drawn on the single phosphor layer 71.

However, such a phosphor wheel cannot emit fluorescence of different colors in order in time. In order to emit fluorescence of different colors, it is necessary to prepare a plurality of phosphor wheels having the configuration shown in FIG. 2, which increases the size of the illumination optical system.

As described above, phosphor wheels having different configurations are properly used depending on applications. Therefore, an illumination optical system having a general-purpose phosphor color wheel that can be used in various applications is desired.

JP 2009-277516 A JP 2011-13313 A

The illumination optical system in one embodiment of the present invention has a color wheel and a plurality of light sources. The color wheel is a substrate that can rotate around a rotation axis, and a plurality of phosphors that are formed on one surface of the substrate in a substantially concentric annular shape around the rotation axis and emit fluorescence of different wavelengths when irradiated with excitation light. And a layer. The plurality of light sources are provided corresponding to the respective phosphor layers and irradiate each phosphor layer with excitation light.

Further, a projection display device provided with the illumination optical system described above is also included in the scope of the present invention.

According to the illumination optical system described above, since each phosphor layer is provided with a separate light source for irradiating excitation light, each phosphor layer is irradiated with excitation light simultaneously, or each phosphor layer is sequentially turned on. Can be irradiated with excitation light. Thereby, a general-purpose illumination optical system capable of emitting a plurality of types of fluorescence at an arbitrary timing can be provided.

It is a top view of the fluorescent substance wheel in the 1st related art. It is a top view of the fluorescent substance wheel in the 2nd related technology. It is a top view of the fluorescent substance wheel in one embodiment of the present invention. FIG. 4 is a side view of the phosphor wheel shown in FIG. 3. It is a schematic diagram which shows the structure of the projection type display apparatus of a 1st Example. It is a schematic diagram which shows the structure of the projection type display apparatus of a 2nd Example. It is a schematic diagram which shows the structure of the transmissive | pervious image display device periphery in the projection type display apparatus of a 2nd Example.

Next, an embodiment of the present invention will be described with reference to the drawings.

An illumination optical system according to an embodiment of the present invention includes a color wheel having a plurality of phosphor layers and a plurality of light sources provided corresponding to the respective phosphor layers. FIG. 3 is a plan view of the color wheel. FIG. 4 is a side view of the color wheel.

The color wheel 20 includes a substrate 2 that can rotate around the rotation axis 10. On one surface of the substrate 2, a first phosphor layer 11 that emits first fluorescence when irradiated with excitation light, a second phosphor layer 12 that emits second fluorescence when irradiated with excitation light, and an excitation light A third phosphor layer 13 that emits third fluorescence upon irradiation is provided. The color wheel 20 includes a drive motor 1 that rotates the substrate 2 provided with the phosphor layers 11 to 13 around the rotation axis 10.

The first phosphor layer 11 is provided on one surface of the substrate 2 in an annular shape around the rotation axis 10. The second phosphor layer 12 is provided on one surface of the substrate 2 in an annular shape around the rotation axis 10. The third phosphor layer 13 is provided on one surface of the substrate 2 in an annular shape around the rotation axis 10. That is, the first phosphor layer 11, the second phosphor layer 12, and the third phosphor layer 13 are formed in a substantially concentric annular shape around the rotation axis 10.

As an example, the first phosphor layer 11 is a phosphor that emits red light, the second phosphor layer 12 is a phosphor that emits green light, and the third phosphor layer 13 is a fluorescence that emits blue light. It can be a body.

In addition to the color wheel 20, the illumination optical system includes a first light source (see also reference numeral 21a shown in FIGS. 5 and 6) and a second light source (reference numeral 21b shown in FIGS. 5 and 6). Reference) and a third light source (not shown).

The first light source 21 a is provided corresponding to the first phosphor layer 11 and irradiates the first phosphor layer 11 with excitation light. The second light source 21 b is provided corresponding to the first phosphor layer 12 and irradiates the second phosphor layer 12 with excitation light. The third light source is provided corresponding to the third phosphor layer 13 and irradiates the third phosphor layer 13 with excitation light.

The first light source 21a, the second light source 21b, and the third light source may be laser light sources. All of these light sources may be light sources that emit blue-violet lasers. Further, the light source corresponding to the phosphor layer emitting blue light may be a light source emitting blue-violet laser, and the two light sources corresponding to the phosphor layers emitting red light and green light may be light sources emitting blue laser. It is not restricted to these examples, The wavelength of the light which each light source emits can be selected arbitrarily, and may mutually differ.

FIG. 3 shows a position (irradiation spot) 14 on the first phosphor layer 11 to which the excitation light emitted from the first light source 21a is irradiated. FIG. 3 shows a position (irradiation spot) 15 on the second phosphor layer 12 to which the excitation light emitted from the second light source 21b is irradiated. FIG. 3 also shows a position (irradiation spot) 16 on the third phosphor layer 13 to which the excitation light emitted from the third light source is irradiated. In FIG. 4, a phosphor layer is formed on the right side of the substrate 2, and excitation light from each of the

light sources

21 a and 21 b enters the phosphor layer from the right side of FIG. 4 toward the substrate 2. .

The illumination optical system includes a control unit that controls driving of the driving motor 1 and light emission of the

light sources

21a and 21b. The control unit freely controls the irradiation time of at least one of the plurality of

light sources

21a and 21b, preferably all of the excitation light. The substrate 2 of the color wheel 20 is rotated in a predetermined direction R by the drive motor 1 while the excitation light emitted from each of the

light sources

21a and 21b irradiates each

phosphor layer

11, 12, and 13. As a result, the irradiation spots 14, 15, and 16 of the respective light sources draw traces 17, 18, and 19 along the annular phosphor layers 11, 12, and 13. Therefore, each

irradiation spot

14, 15, 16 does not always irradiate the same portion of the phosphor layers 11, 12, 13, and the deterioration of the phosphor layers 11, 12, 13 due to heat generation can be suppressed.

According to the illumination optical system described above, since the

individual light sources

21a and 21b for irradiating the respective phosphor layers 11, 12, and 13 with the excitation light are provided, the plurality of phosphor layers 11, 12, and 13 are simultaneously excited. It is possible to irradiate light, or to sequentially irradiate each

phosphor layer

11, 12, 13 with excitation light. Thereby, a general-purpose illumination optical system capable of emitting a plurality of types of fluorescence at an arbitrary timing can be provided.

In the above embodiment, an illumination optical system that emits light of three colors has been described. However, the present invention can be applied to an illumination optical system that emits light of two or more colors. In this case, the illumination optical system is provided corresponding to each of the plurality of phosphor layers formed in a substantially concentric annular shape around the rotation axis 10 and each phosphor layer. It is only necessary to have a plurality of light sources that emit excitation light.

For example, in an illumination optical system that emits light of two colors, there are only two types of phosphor layers provided on the color wheel, and only two light sources are required.

In an illumination optical system that emits light of four colors, the color wheel only needs to include four types of phosphor layers and four light sources. In this case, the four types of phosphor layers may each be a phosphor that emits red light, a phosphor that emits blue light, a phosphor that emits green light, or a phosphor that emits yellow light.

In FIG. 3, excitation light irradiation spots 14, 15, and 16 are provided on the respective phosphor layers 11, 12, and 13. In this example, the excitation spot on the phosphor layer 11 that emits red light is referred to as a first irradiation spot 14, and the excitation spot on the phosphor layer 12 that emits green light is referred to as a second irradiation spot 15. An excitation spot on the phosphor layer 13 that emits light is referred to as a third irradiation spot 15.

The first irradiation spot 14, the second irradiation spot 15, and the third irradiation spot 16 are center angles α 1, α 2, which are substantially equal to each other with respect to the rotation direction R around the rotation axis 10. It is preferable that they are spaced apart by α3.

In FIG. 3, an angle formed by a straight line connecting the rotation axis 10 and the first irradiation spot 14 and a straight line connecting the rotation axis 10 and the second irradiation spot 15 is defined as α1. An angle between a straight line connecting the rotation axis 10 and the second irradiation spot 15 and a straight line connecting the rotation axis 10 and the third irradiation spot 16 is defined as α2. Furthermore, an angle formed by a straight line connecting the rotation axis 10 to the third irradiation spot 16 and a straight line connecting the rotation axis 10 to the first irradiation spot 14 is defined as α3. At this time, the angles α1, α2, and α3 are substantially the same angle, that is, substantially 120 °.

Even if the illumination optical system has an arbitrary number of phosphor layers and irradiation spots, the irradiation spots are preferably arranged apart from each other by substantially the same central angle.

FIG. 5 shows the configuration of the projection display apparatus in the first embodiment provided with the illumination optical system described above. The illumination optical system includes a color wheel 20 shown in FIGS. 3 and 4 and a motor 1 that rotationally drives the color wheel 20. A first phosphor layer 11, a second phosphor layer 12, and a third phosphor layer 13 are provided concentrically on one surface of the substrate 2 of the color wheel 20. The illumination optical system includes

light sources

21a and 21b that irradiate the phosphor layers 11, 12, and 13 with excitation light. In FIG. 5, one of the three light sources is not shown because it is disposed behind the dichroic mirror 25c.

The projection display device shown in FIG. 6 will be further described. The excitation light emitted from the first light source 21a is reflected by the dichroic mirror 25a and enters the first phosphor layer 11 emitting red light substantially perpendicularly. Red light is emitted from the first phosphor layer 11 by the irradiation of the excitation light. The red light is converted into substantially parallel light by the collimator lens group 23a and passes through the dichroic mirror 25a.

The excitation light emitted from the second light source 21b is reflected by the dichroic mirror 25b and is incident substantially perpendicularly on the second phosphor layer 12 that emits green light. Green light is emitted from the second phosphor layer 12 by the irradiation of the excitation light. The green light is converted into substantially parallel light by the collimator lens group 23b and passes through the dichroic mirror 25b.

Excitation light emitted from the third light source is reflected by the dichroic mirror 25c and is incident substantially vertically on the third phosphor layer 13 that emits blue light. Blue light is emitted from the third phosphor layer 13 by the irradiation of the excitation light. This blue light is converted into substantially parallel light by the collimator lens group 23c and passes through the dichroic mirror 25c.

The red light passes through the dichroic mirror 25a and is then reflected by the reflection mirror 53a. The reflection surface of the reflection mirror 53a is perpendicular to the plane including the optical path of red light emitted from the first phosphor layer 11 and the optical path of green light emitted from the second phosphor layer 12, and is reflective. The angle may be set to be substantially 45 degrees.

The red light reflected by the reflecting mirror 53 a is reflected by the first dichroic mirror 51. The green light emitted from the second phosphor layer 12 passes through the first dichroic mirror 51. The red light and the green light travel in the same direction after passing through the first dichroic mirror 51. In other words, the first dichroic mirror 51 spatially combines red light and green light.

At this time, the reflection mirror 53a and the first dichroic mirror 51 are preferably arranged in parallel. That is, the incident angle of green light on the first dichroic mirror 51 is 45 degrees, and the incident angle of red light on the first dichroic mirror 51 is also 45 degrees. The first dichroic mirror 51 has a characteristic that reflects light having a longer wavelength than the red light emitted from the first phosphor layer and transmits light having a shorter wavelength than the red light. ing.

The combined light obtained by combining the red light and the green light is incident on the reflection mirror 53b at an incident angle of substantially 45 degrees and proceeds toward the second dichroic mirror 52. The reflecting surface of the reflecting mirror 53b is perpendicular to the plane including the optical path of green light emitted from the second phosphor layer 12 and the optical path of blue light emitted from the third phosphor layer 13, and is reflective. The angle may be set to be substantially 45 degrees.

The combined light of red light and green light reflected by the reflecting mirror 53 b is reflected by the second dichroic mirror 52. Blue light emitted from the third phosphor layer 13 passes through the second dichroic mirror 52. The combined light of red light and green light and blue light travel in the same direction after passing through the second dichroic mirror 52. In other words, the second dichroic mirror 52 spatially combines red light, green light, and blue light.

The reflecting mirror 53b and the second dichroic mirror 52 are preferably arranged in parallel. That is, the incident angle of the combined light of the red light and the green light on the second dichroic mirror 52 is substantially 45 degrees, and the incident angle of the blue light on the second dichroic mirror 52 is also substantially 45 degrees. It is. Here, the second dichroic mirror 52 reflects light having a wavelength longer than that of the green light emitted from the second phosphor layer 12 and transmits light having a wavelength shorter than that of the green light. Have.

As described above, red light, green light, and blue light are synthesized by the first dichroic mirror 51 and the second dichroic mirror 52. In other words, the illumination optical system includes a synthesis optical system that synthesizes the light emitted from the phosphor layers 11, 12, and 13. The synthesis optical system includes at least the first dichroic mirror 51 and the second dichroic. A mirror 52 is included.

The three colors of light synthesized by the illumination optical system are incident on the lot lens 27 via the condenser lens 26. The lot lens 27 makes the illuminance distribution of the combined light uniform. The lot lens 27 may be a light tunnel configured by bonding four rectangular mirrors. The lot lens 27 converts the light distribution into a rectangle. The light passing through the rod lens 27 passes through the

relay lens groups

28 and 29 and is irradiated onto the reflective image element (light valve) 30 while maintaining a substantially rectangular shape. The light applied to the reflective image element 30 is enlarged and projected on the screen via the projection lens 31. The image element 30 modulates incident light according to an image signal. As the reflective image element 30, for example, a digital mirror device (DMD) can be used.

The DMD 30 is a semiconductor projection device including a large number of micromirrors arranged in a matrix. Each micromirror corresponds to a pixel of the projected image. Each micromirror is configured such that its mirror surface can be inclined at a predetermined angle, for example, ± 12 degrees or ± 10 degrees around the torsion axis.

By driving the electrode provided below each micromirror, each micromirror can be switched between an ON state (+12 degrees tilt) and an OFF state (−12 degrees). The light incident on the micro mirror in the ON state is reflected in the direction of the projection lens 31 and is enlarged and projected on the screen. The light incident on the micro mirror in the OFF state is reflected in a direction different from that of the projection lens 31 and is not projected on the screen. In each micromirror, the ON state and the OFF state are switched at high speed, and the temporal ratio between the ON state and the OFF state is changed. Thereby, the gradation of each pixel can be expressed.

In the above embodiment, the lot lens 27 is positioned on a straight line that passes through the third irradiation spot 16 of the third phosphor layer 13 that emits blue light having the shortest wavelength and is perpendicular to the substrate 2. The position of the rod lens 27 is not limited to this position, but a straight line passing through any one of the first irradiation spot 14, the second irradiation spot 15, and the third irradiation spot 16 among straight lines perpendicular to the substrate 2. It is preferable to be arranged on the top. However, in consideration of photosynthesis by the dichroic mirrors 51 and 52, the rod lens 27 is placed on a straight line passing through the phosphor layer that excites the light with the longest wavelength or the phosphor layer that excites the light with the shortest wavelength. It is more preferable.

In the projection type display device of the present embodiment, the light paths of the light of each color are synthesized, but the light of each color is emitted sequentially in time. In other words, red light, blue light, and green light are emitted in a time division manner. In the projection type display device of this embodiment, separate light sources for irradiating the phosphor layers 11, 12, and 13 with excitation light are used. Therefore, by controlling the light emission time of each light source, the fluorescence of each color is controlled. The lighting time can be freely controlled.

The lighting time of each color light can be freely changed as long as the timing and timing of the DMD 30 micro mirror are matched. It is also possible to light two colors or three colors simultaneously.

On the other hand, it is also possible to configure a projection display device that irradiates light of each color in a time-sharing manner using the phosphor wheel 60 shown in FIG. However, in this case, as described above, the ratio of the lighting time of the fluorescence emitted from each phosphor layer is determined by the size of the region where each phosphor layer is formed, and cannot be freely controlled. .

In addition, from the viewpoint of manufacturing, the application area of the phosphor applied to the phosphor wheel 60 may vary individually. When variation occurs in the size of the application area of each phosphor, it is necessary to adjust the timing of synchronization with the DMD 30.

Further, when the model of the projection display device is changed, an improvement in which the light output of the light source is increased may be performed, but due to the characteristics of the phosphor applied to the phosphor wheel 60, the increase in the output of the excitation light can be prevented. The increase in the luminous output of the phosphor is not uniform. That is, the balance of the amount of fluorescent light of each color changes due to the change in the output of the light source. This also changes the color coordinates. As a result, it becomes necessary to adjust the size of the phosphor region applied to the color wheel.

On the other hand, since the projection type display apparatus of the said Example is equipped with the separate light source which irradiates each

phosphor layer

11,12,13 with excitation light, it irradiates each

phosphor layer

11,12,13. It is possible to freely adjust the irradiation time of the excitation light. In addition to the color wheel 20 that emits two types of fluorescent light, when using a light source such as an LED or LD that emits light of a different color, it is possible to freely adjust the mixed color due to variations in individual light sources. This has the effect of suppressing color variations among products. The LED light source has an effect that it is possible to realize adjustment of the mixed color and adjustment of the light amount of each color without changing the color wheel 20 in response to the model change caused by changing the light amount and color of the LD used without wavelength conversion. .

As described above, in the projection display apparatus including the illumination optical system having the color wheel 20 of the present invention, there is an advantage that the lighting time of each color light can be freely changed by using the common color wheel 20. The lighting time of each color light can be easily performed by the control unit of the illumination optical system controlling the light emission time of each

light source

23a, 23b.

FIG. 6 shows the configuration of the projection display device in the second embodiment provided with the illumination optical system described above. The mechanical configuration of the illumination optical system is the same as that shown in FIG. The illumination optical system synthesizes the light emitted from the phosphor layers 11, 12, and 13 as in the projection display device in the first embodiment. This combined light passes through the fly-eye lens group 33 and the

field lenses

34 and 35.

The combined light that has passed through the lens 35 is separated into light of each color by the dichroic mirror 36. Specifically, the dichroic mirror 36 reflects red light and transmits green light and blue light. The red light reflected by the dichroic mirror 36 is reflected by the reflection mirror 40 and enters the first transmission type image element (light valve) 44a.

The combined light of green light and blue light transmitted through the dichroic mirror 36 enters the dichroic mirror 37. The dichroic mirror 37 separates green light and blue light. Specifically, the green light is reflected by the dichroic mirror 37 and enters the second transmissive image element 44b.

The blue light transmitted through the dichroic mirror 37 enters the third transmission type image element 44 c via the lens system 38 and the reflection mirror 39. These

image elements

44a, 44b and 44c modulate incident light in accordance with the image signal. A liquid crystal panel can be used as the first to third transmissive image elements.

FIG. 7 shows a configuration 41 around the liquid crystal panel shown in FIG. The projection display device according to the present embodiment corresponds to the light of each color and includes three

liquid crystal panels

44a, 44b, and 44c.

Polarizing

plates

43a, 43b, 43c, 45a, 45b, and 45c are provided on both sides of each

liquid crystal panel

44a, 44b, and 44c. The light of each color enters the

condenser lenses

42a, 42b, and 42c before entering the liquid crystal panels 44a to 44c and the polarizing plates 43a to 43c and 45a to 45c.

The first liquid crystal panel 44a changes the polarization state of red light for each pixel. The second liquid crystal panel 44b changes the polarization state of green light for each pixel. The third liquid crystal panel 44c changes the polarization state of blue light for each pixel. The light of each color can be projected as an image by the action of the liquid crystal panels 44a to 44c and the polarizing plates 43a to 43c and 45a to 45c.

The light of each color that has passed through the liquid crystal panels 44a to 44c and the polarizing plates 43a to 43c and 45a to 45c is incident on the cross dichroic prism 46. The light of each color is synthesized by the cross dichroic prism 46 and then projected onto a screen or the like through the projection lens 31. In this way, a full color image is projected on a projection object such as a screen.

In the above-described embodiment, the three colors of light are synthesized by the synthesis

optical systems

51 and 52, and then separated into the respective colors by the separation

optical systems

36 and 37. Not limited to such a configuration, the light of each color may be incident on the corresponding liquid crystal panels 44a to 44c without being synthesized.

As in this embodiment, according to the projection display device including the display device that expresses gradation using the liquid crystal panels 44a to 44c, the projected image or video can be brightened.

In a projection display device provided with image elements 44a to 44c for each color of light, light of each color is normally continuously irradiated. In other words, each

light source

21a, 21b irradiates each

phosphor layer

11, 12, 13 simultaneously and continuously.

In the phosphor wheel 70 shown in FIG. 2, it is necessary to use three types of phosphor wheels 70 having different phosphor layers in order to realize a full-color image or video. On the other hand, in this embodiment, since a full color image or video can be displayed with the single color wheel 20, the projection display device can be miniaturized.

In the first and second embodiments described above, the projection type display device including the color wheel 20 having the three types of phosphor layers 11, 12, 13 has been described. However, the color wheel 20 may have two types of phosphor layers. In this case, the projection display device only needs to include another light source that emits light of another color, for example, a light emitting diode (LED).

The luminous efficiency of the phosphor layer depends on the efficiency of the laser that is the excitation light. However, the luminous efficiency of the phosphor layer that emits green light is higher than that of the LED, and the phosphor layer that emits red light is about the same as the luminous efficiency of the LED. Therefore, the projection display device may be configured by a color wheel having a phosphor layer that emits green light and a phosphor layer that emits red light, and another light source that emits blue light. In this case, there is an advantage that a small and bright projection display device can be realized.

The preferred embodiments of the present invention have been presented and described in detail above, but the present invention is not limited to the above-described embodiments, and it is understood that various changes and modifications can be made without departing from the gist. I want to be.

DESCRIPTION OF SYMBOLS 1 Drive motor 2 Board | substrate 10 Rotating shaft 11 1st fluorescent substance layer 12 2nd fluorescent substance layer 13 3rd fluorescent substance layer 14 1st irradiation spot 15 2nd irradiation spot 16 3rd irradiation spot 20 Color wheel 21a First light source 21b Second light source

Claims

A substrate rotatable around a rotation axis, and a plurality of phosphor layers which are formed on one surface of the substrate in a substantially concentric annular shape around the rotation axis and emit fluorescence of different wavelengths by irradiation of excitation light; A color wheel having,
An illumination optical system comprising: a plurality of light sources provided corresponding to each of the phosphor layers and irradiating each of the phosphor layers with excitation light.
The illumination optical system according to claim 1,
An illumination optical system having a control unit that controls irradiation time of at least one excitation light of the plurality of light sources.
The illumination optical system according to claim 1 or 2,
The illumination optical system, wherein irradiation spots on which the plurality of light sources irradiate each of the phosphor layers are arranged apart from each other by substantially equal central angles in a rotation direction about the rotation axis.
The illumination optical system according to any one of claims 1 to 3,
One of the plurality of phosphor layers is a phosphor emitting red fluorescence,
Another one of the plurality of phosphor layers is a phosphor emitting green fluorescence,
An illumination optical system in which another one of the plurality of phosphor layers is a phosphor that emits blue fluorescence.
A projection display device comprising the illumination optical system according to any one of claims 1 to 4.
The projection type display device according to claim 5,
A synthesis optical system that spatially synthesizes the fluorescence emitted from the plurality of phosphor layers;
A projection display device comprising: a single image element that modulates light passing through the combining optical system in accordance with an image signal.
The projection type display device according to claim 6,
The projection display device, wherein the plurality of light sources emit the excitation light in order in a time-division manner.
The projection type display device according to claim 5,
A projection display device comprising a plurality of image elements for modulating each fluorescence emitted from the plurality of phosphor layers according to an image signal.
The projection type display device according to claim 8,
A projection display device in which the plurality of light sources emit the excitation light simultaneously.