JP2004325854A - Liquid crystal projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that micromachining of an element by a method of increasing element density for a higher-definition liquid crystal projector is limited, size reduction of pixels results in a decrease in reflection efficiency, and a method of making an element panel large-sized causes optical constitution components to be larger in size. <P>SOLUTION: This liquid crystal projector is configured to make green-light components G1 and G2, modulated with an image and reflected by reflection type liquid crystal modulating elements 23 and 24, incident a projection lens 6 through a color component composition part 4. A red-light component R and a blue-light component B which are modulated with the image and reflected by reflection type liquid crystal modulating elements 33 and 34 made incident on the projection lens 6 through the color component composition part 4, and the reflection type liquid crystal modulating elements 23 and 24, and 33 and 34 are so set that respective pixels of the R component and B component projected on a screen by the projection lens 6 and pixels of a G1 component are at the same positions and pixels of a G2 component shift from pixels of the G1 component, etc., by a 1/2-pixel pitch in the horizontal and vertical directions of a formed image. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal projector, and more particularly, to a liquid crystal projector used as a reflection type projection projector device.
[0002]
[Prior art]
In recent years, displays have tended to be increasingly finer and larger, and accordingly, data projectors and projection TVs using projection technology have been developed. Recently, a reflective liquid crystal modulation element has been applied to an element for controlling an image. The reflective liquid crystal modulator can increase the aperture ratio as compared with the conventional transmissive liquid crystal modulator, can easily achieve high density, and can realize a compact and highly efficient projector.
[0003]
As a liquid crystal projector using the above-mentioned reflection type liquid crystal modulator, a liquid crystal projector (ColorQuad) using four polarizing beam splitters (PBS) and a color polarizer in recent years. ^TM ) Is disclosed (for example, see Patent Document 1).
[0004]
In the conventional liquid crystal projector described in Patent Document 1, a color separation unit includes a first separated light including a first color component among three primary colors, and a second separated light including second and third color components having different polarization directions. After splitting the light into two separated lights and emitting both separated lights in directions orthogonal to each other, the first separated light is incident on a first PBS having a first reflective light modulation element and modulated, After being emitted in a direction orthogonal to the incident light, the second separated light is incident on the first PBS, and then the second and third color components are separated in directions orthogonal to each other. After being modulated by the reflection-type light modulation element, the light is combined by the second PBS, emitted in a direction orthogonal to the incident light, and enters the color combining unit. The first and second separated lights combined by the color combining unit are enlarged and projected on a screen by a projection optical system to display an image.
[0005]
The color separation unit has a first polarization direction rotation unit that rotates the polarization direction of the first color component by 90 degrees, and a second polarization direction that rotates the polarization direction of the second color component by 90 degrees. A third PBS having a direction rotating unit; and the color combining unit including a fourth PBS having a third polarization direction rotating unit for rotating the polarization direction of the second color component by 90 °. .
[0006]
According to the conventional liquid crystal projector described in Patent Document 1, the second PBS is used for separating the second and third color components, and the second and third light are modulated by the corresponding reflective liquid crystal panels. Since it is used for color synthesis of the image light, it is not necessary to use a dichroic mirror or a total reflection mirror for color separation to go around an extra optical path, and the device can be downsized.
[0007]
[Patent Document 1]
JP-A-2000-284228 (pages 3 and 5)
[0008]
[Problems to be solved by the invention]
However, in recent years, a market demand for a high definition display has appeared, and in order to satisfy the demand, it is necessary to increase the element density or increase the number of pixels of the liquid crystal projector by a method of enlarging the element panel. . The former method of increasing the element density has a problem in that the element density has a limit of fine processing, and the reduction in the size of the pixel leads to a decrease in reflection efficiency. On the other hand, the latter method of enlarging the element panel requires an enlargement of an optical engine and an enlargement of a projection imaging lens for the enlargement of the element panel, and the enlargement of optical components is inevitable. There is a problem.
[0009]
The present invention has been made in view of the above points, and has as its object to provide a liquid crystal projector capable of projecting a high-definition image with a projection unit having a small configuration.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a liquid crystal projector according to a first aspect of the present invention provides an illumination light source unit that emits white light, a white light emitted from the illumination light source unit, a green light component having a first polarization plane, The first polarization plane is separated into a primary color light component composed of a red light component and a blue light component having a second polarization plane whose polarization plane is different from each other by 90 degrees, and is separated into color components emitted in directions orthogonal to each other. And the green light component are separated into a short-wavelength green light component and a long-wavelength green light component whose polarization planes are different from each other by 90 degrees, and the short-wavelength green light component is projected on the first reflective liquid crystal modulator. The green light component in the long wavelength region is modulated and reflected by the projected image in the second reflective liquid crystal modulator, and is modulated and reflected from the first and second reflective liquid crystal modulators, respectively. Short wavelength green light component A first separating / combining unit that emits a long-wavelength green light component in a direction orthogonal to the direction of incidence of the green light component; and a primary color light component composed of a red light component and a blue light component. The light is separated into a red light component and a blue light component that differ by 90 degrees, the red light component is modulated and reflected by a projection image in a third reflective liquid crystal modulator, and the blue light component is projected in a fourth reflective liquid crystal modulator. The red and blue light components modulated and reflected by the third and fourth reflective liquid crystal modulators are emitted in directions orthogonal to the incident direction of the primary color light components, respectively. The second separation / combination unit and the respective polarization planes of the short wavelength green light component and the long wavelength green light component emitted from the first separation / combination unit are respectively assigned to the first or second polarization plane. Convert and second After converting each of the polarization planes of the red light component and the blue light component emitted from the separation / synthesis unit into either the first or second polarization plane, these four primary color light components are synthesized respectively and in the same direction. A color component synthesizing section, and a projection optical system for enlarging and projecting the synthesized light synthesized by the color component synthesizing section, wherein at least the first and second reflective liquid crystal modulation elements are composed of first and second reflective liquid crystal modulation elements. When the green light components of the short wavelength region and the long wavelength region modulated by the reflection type liquid crystal modulation element are imaged on a screen via a projection optical system, a 1/2 pixel pitch in the horizontal direction of the formed image Alternatively, the display is set to be displayed at a pixel position shifted by a half pixel pitch in each of the horizontal direction and the vertical direction.
[0011]
According to the present invention, a green light component having high sensitivity in human visual recognition characteristics is divided into a short wavelength region and a long wavelength region, and each pixel is divided in the horizontal direction of the image by 1/2 pixel pitch or horizontal. Since the image is displayed at a pixel position shifted by a half pixel pitch in the direction and the vertical direction, the resolution in the horizontal direction or in both the horizontal direction and the vertical direction can be increased. Further, according to the present invention, it is possible to achieve a small configuration using four reflective liquid crystal modulation elements in one projection unit without using a large reflective liquid crystal modulation element.
[0012]
In order to achieve the above object, a second invention provides an illumination light source unit that emits white light, a white light emitted from the illumination light source unit, a green light component having a first polarization plane, The first polarization plane is a color component separation unit that separates into a primary color light component composed of a red light component and a blue light component having a second polarization plane whose polarization plane is different from each other by 90 degrees and emits light in directions orthogonal to each other. And the green light component is divided into a first and a second green light component whose polarization planes are different from each other by 90 degrees, and the first green light component is modulated by a first reflection type liquid crystal modulation element by a projection image. The second green light component is reflected and modulated by the second reflective liquid crystal modulator according to the projected image and reflected, and the first and second modulated liquid crystal modulators are respectively modulated and reflected by the first and second reflective liquid crystal modulators. The second green light component is defined as the way in which the green light component is incident. A first separation / synthesis unit that emits light in a direction orthogonal to the first direction, and a primary color light component composed of a red light component and a blue light component are separated into a red light component and a blue light component whose polarization planes are different from each other by 90 degrees. The separated red light component is modulated and reflected by the third reflection type liquid crystal modulation element according to the projection image, and the separated blue light component is modulated and reflected by the fourth reflection type liquid crystal modulation element according to the projection image. A second separation / synthesis unit that emits a red light component and a blue light component modulated and reflected from the third and fourth reflective liquid crystal modulation elements, respectively, in a direction orthogonal to the incident direction of the primary color light component; The first and second green light components emitted from the first separation / combination unit and the red light component and blue light component emitted from the second separation / combination unit are transmitted or reflected in accordance with the wavelength range, respectively. To do A color component combining unit that combines the four primary color light components and emits the light in the same direction, and a projection optical system that enlarges and projects the combined light combined by the color component combining unit. And when the first and second green light components modulated by the first and second reflective liquid crystal modulators are imaged on a screen via a projection optical system. , The image is formed so as to be displayed at a pixel position shifted by a half pixel pitch in the horizontal direction or by a half pixel pitch in the horizontal direction and the vertical direction, respectively.
[0013]
The present invention is different from the first invention in that green light is not divided into two in a wavelength region, but is divided into two light beams, that is, first and second green light components. Similarly to the above, the pixels of the two green light components, which are highly sensitive to human visual characteristics, are shifted by a half pixel pitch in the horizontal direction of the formed image or by a half pixel pitch in the horizontal and vertical directions. Since the image is displayed at the pixel position, the resolution in the horizontal direction or in both the horizontal direction and the vertical direction can be increased. Further, according to the present invention, it is possible to achieve a small configuration using four reflective liquid crystal modulation elements in one projection unit without using a large reflective liquid crystal modulation element.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of a liquid crystal projector according to the present invention. In FIG. 1, the liquid crystal projector according to the present embodiment includes a projection unit (optical engine) including an illumination light source unit 5, a projection lens 6, and a color separation / combination unit 7, and a power supply / control unit 8. These are housed in a housing 99.
[0015]
FIG. 2 shows a configuration diagram of the first embodiment of the projection unit. As shown in FIG. 1, the projection unit according to the first embodiment includes a color component separation unit 1, a first color component separation / synthesis unit 2, a second color component separation / synthesis unit 3, and a color unit. It comprises a component combining section 4, an illumination light source section 5, and a projection lens 6. The color component separation unit 1, the first color component separation / synthesis unit 2, the second color component separation / synthesis unit 3, and the color component synthesis unit 4 constitute the color separation / synthesis unit 7 in FIG. are doing.
[0016]
2, the illumination light source unit 5 includes a lamp 51 and a polarizing plate 52. The polarizing plate 52 transmits only the P-polarized component or only the S-polarized component of the white non-polarized light emitted from the lamp 51, and enters the color component separating unit 1. The color component separation unit 1 includes a color separation polarization beam splitter (hereinafter, referred to as PBS) 11 and a first color polarizer 12 disposed opposite to the main surface of the color separation PBS 11 on the illumination light source unit 5 side. I have.
[0017]
The first color component separation / synthesis unit 2 includes a second color polarizer 22 disposed facing the main surface on the color component separation unit 1 side, a separation / synthesis PBS 21, and incident light transmitted through the separation / synthesis PBS 21. A first reflection-type liquid crystal modulation element 23 disposed on the main surface side reaching the second reflection-type liquid crystal modulation element 24 disposed on the main surface side reflected by the reflection surface of the separation / combination PBS 21 and reaching the first reflection-type liquid crystal modulation element 24; It has.
[0018]
The second color component separation / synthesis unit 3 includes a third color polarizer 32 and a separation / synthesis PBS 31 disposed opposite to the main surface on the color component separation unit 1 side, and a separation / synthesis PBS 31 for separating incident light. A third reflective liquid crystal modulation element 33 disposed on the main surface side through which light is transmitted, and a fourth reflective liquid crystal modulation element disposed on the main surface side reflected by the reflection surface of the separation / combination PBS 21. And an element 34.
[0019]
Further, the color component synthesizing unit 4 includes a synthesizing PBS 41, a fourth color polarizer 42 disposed on the main surface side of the synthesizing PBS 41 facing the first separation / synthesis PBS 21, and a fourth component of the synthesizing PBS 41. And a fifth color polarizer 43 disposed on the main surface side facing the separation / combination unit PBS31 of the second. The light emitting main surface of the combining PBS 41, that is, the fifth color polarizer 43 is disposed on the main surface side facing the projection lens 6. In this configuration, six color polarizers 44 are arranged. Each of the four reflection-type liquid crystal modulation elements 23, 24, 33, and 34 has a large number of pixels arranged in a two-dimensional matrix, for example. The light is reflected with modulation or without modulation. At this time, the polarization plane is rotated by 90 degrees only when modulated.
[0020]
Next, the operation of the present embodiment will be described. For example, the S-polarized light emitted from the illumination light source unit 5 is converted into a P-polarized light by rotating the polarization direction of the primary color light component in a predetermined wavelength range by 90 degrees by the first color polarizer 12 to become a P-polarized light. The light components in the region directly enter the separation PBS 11 without rotating the polarization plane. The separating PBS 11 transmits the P-polarized light component of the transmitted light of the first color polarizer 12 and guides the P-polarized light component to the first color component separating / combining unit 2, and the S-polarized light component is reflected on the reflection surface of the separating PBS 11. The light is emitted in a direction orthogonal to the optical path of the incident light, and is guided to the second color component separation / combination unit 3.
[0021]
The P-polarized light transmitted through the separating PBS 11 is converted into S-polarized light by rotating the polarization plane of the primary color light component in a predetermined wavelength range by 90 degrees by the second color polarizer 22, and is converted into S-polarized light. The polarization plane is incident on the separation / synthesis PBS 21 without being rotated. The S-polarized light from the color polarizer 22 is reflected by the reflection surface of the separating / combining PBS 21 and is incident on the second reflective liquid crystal modulator 24. On the other hand, the P-polarized light component that has just passed through the second color polarizer 22 passes through the separation / combination PBS 21 and enters the first reflective liquid crystal modulator 23.
[0022]
The light components incident on the first reflection type liquid crystal modulation element 23 and the second reflection type liquid crystal modulation element 24 are reflected with their polarization controlled in accordance with the image to be projected. In a device having a bright projected image, the incident light is reflected by being rotated by 90 degrees, and in a dark device, the polarization plane is reflected as it is. That is, the P-polarized light incident on the first reflective liquid crystal modulation element 23 is reflected as S-polarized light in accordance with the image to be projected, and is reflected on the reflection surface of the separating / combining PBS 21 to combine color components. The light enters the unit 4. On the other hand, the P-polarized light component in the wavelength range whose polarization plane is not controlled by the first reflection type liquid crystal modulation element 23 is transmitted through the reflection plane of the separation / combination PBS 21 and returned to the illumination light source unit 5.
[0023]
Similarly, the S-polarized light that has entered the second reflective liquid crystal modulation element 24 is reflected as P-polarized light according to the image to be projected, passes through the reflecting surface of the separating / combining PBS 21, and receives color components. The light enters the combining unit 4. On the other hand, the S-polarized light component in the wavelength range where the polarization plane is not controlled by the second reflection type liquid crystal modulation element 24 is reflected by the reflection plane of the separation / combination PBS 21 and returned to the illumination light source unit 5.
[0024]
On the other hand, the S-polarized light reflected by the separating PBS 11 is turned into a P-polarized light by rotating the polarization plane of the primary color light component in a predetermined wavelength range by 90 degrees by the third color polarizer 32, and enters the separating / combining PBS 31. Then, the light passes through the reflection surface and enters the third reflection type liquid crystal modulation element 33. On the other hand, the S-polarized light component in the wavelength region where the polarization plane is not rotated by the third color polarizer 32 but transmitted is reflected by the reflection surface of the separation / combination PBS 31 and enters the fourth reflection type liquid crystal modulation element 34. Is done.
[0025]
The light components incident on the third reflective liquid crystal modulator 33 and the fourth reflective liquid crystal modulator 34 are reflected with their polarization planes controlled in accordance with the image to be projected. In a device having a bright projected image, the incident light is reflected by being rotated by 90 degrees, and in a dark device, the polarization plane is reflected as it is. That is, the P-polarized light incident on the third reflective liquid crystal modulation element 33 is modulated into S-polarized light according to the image and reflected, reflected by the reflection surface of the separation / combination PBS 31, and transmitted to the color component combining section 4. Incident. On the other hand, the P-polarized component in the wavelength region reflected by the third reflective liquid crystal modulation element 33 without controlling the polarization plane is transmitted through the reflection plane of the separation / combination PBS 31 and returned to the illumination light source unit 5.
[0026]
Similarly, the S-polarized light incident on the fourth reflective liquid crystal modulation element 34 is modulated into P-polarized light according to the image, reflected, transmitted through the reflection surface of the separation / combination PBS 31, and transmitted to the color component combining section. 4 is incident. The S-polarized light component in the wavelength range reflected by the fourth reflection type liquid crystal modulation element 34 without controlling the polarization plane is reflected by the reflection plane of the separating / combining PBS 31 and returned to the illumination light source unit 5.
[0027]
The fourth color polarizer 42 installed on the main surface of the combining PBS 41 facing the separation / combining PBS 21 is a polarization plane of P-polarized primary color light incident from the second reflective liquid crystal modulation element 24. Is rotated by 90 degrees, and is incident on the PBS 41 for light component synthesis. On the other hand, the primary color light incident on the fourth color polarizer 42 from the first reflection type liquid crystal modulation element 23 is S-polarized light, so that the polarization plane of the fourth color polarizer 42 is transmitted without being rotated. The light is then incident on the PBS 41 for light component synthesis.
[0028]
Therefore, the primary color lights from the first and second reflection type liquid crystal modulation elements 23 and 24 are both S-polarized light and are incident on the light component synthesizing PBS 41, and are reflected on the reflection surface of the light component synthesizing PBS 41. Then, the light is guided to the projection lens 6 via the sixth color polarizer 44 and projected and formed on a screen (not shown). The sixth color polarizer 44 rotates the polarization plane in the wavelength range of the S-polarized light from the reflection type liquid crystal modulation elements 23 and 24 by 90 degrees, that is, enters the projection lens 6 as a P-polarized wave.
[0029]
On the other hand, the fifth color polarizer 43 provided between the opposing main surfaces of the combining PBS 41 and the separating / combining PBS 31 has a polarization plane of the S-polarized primary color light from the third reflective liquid crystal modulator 33. Is rotated by 90 degrees, and is incident on the PBS 41 for light component synthesis. On the other hand, since the primary color light from the fourth reflection type liquid crystal modulation element 34 is P-polarized light, the polarization plane of the fifth color polarizer 43 is transmitted as it is without being rotated and is transmitted to the light component synthesizing PBS 41. Incident.
[0030]
Accordingly, the primary color lights from the third and fourth reflection type liquid crystal modulation elements 33 and 34 become P-polarized light and are incident on the light component synthesizing PBS 41, so that the reflection surface of the light component synthesizing PBS 41 is transmitted. Further, the polarization plane is transmitted by the sixth color polarizer 44 without being rotated, guided to the projection lens 6, and thereby projected and formed on a screen (not shown).
[0031]
The sixth color polarizer 44 is provided for improving performance. That is, in general, the spectral characteristics of the PBS are such that the transmitted P-polarized light is polarized with a large extinction ratio of 99.8% or more, while the S-polarized light reflected by the reflecting surface is approximately 90% S-polarized light and the remaining approximately 90%. 10% is P-polarized light. For this reason, the S-polarized light reflected by the reflection surface of the PBS 21 and further reflected by the reflection surface of the PBS 41 toward the projection lens 6 in the projection imaging optical system of FIG. In the primary color light component, the ratio of unnecessary light is larger than the other primary color light components, and the contrast ratio cannot be increased. Therefore, in the present embodiment, all of the four primary color lights modulated by the image, which are emitted from the PBS 41, are converted into the same P-polarized light by the sixth color polarizer 44, and this is converted to a polarizing plate (not shown). ), The unnecessary light is removed and the light enters the projection lens 6.
[0032]
Next, a method of color separation in the present embodiment will be described in more detail with reference to the configuration diagram of FIG. FIG. 3 is a configuration diagram of a main part of FIG. 2. In FIG. 3, the same components as those of FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 3, the white light emitted from the lamp 51 is non-polarized light, and only the S-polarized light component is transmitted by the polarizer 52 and guided to the color component separation unit 1.
[0033]
In the color component separation unit 1, the color polarizer 12 rotates the polarization plane of white light, for example, G (green light wavelength region) component light of 500 nm to 590 nm, by 90 degrees and enters the color component separation PBS 11 as P-polarized light. I do. On the other hand, the R (red light wavelength) component and the B (blue light wavelength) component other than the above-mentioned wavelength range are not subjected to the rotation of the polarization plane in the color polarizer 12, and are separated as S-polarized light. Incident on the PBS 11 for use.
[0034]
The color component separating PBS 11 reflects the R and B component light incident as S-polarized light on the PBS reflecting surface, in a direction orthogonal to the optical path of the incident light, that is, the color of the second color separating / combining unit 3. The light is emitted in the direction of the polarizer 32. On the other hand, the color component separating PBS 11 transmits the green light component G converted into P-polarized light by the first color polarizer 12 and directly enters the first color separating / combining unit 2.
[0035]
In the first color separation / synthesis unit 2, of the G component of the P-polarized light incident from the color component separation PBS 11, the second color polarizer 22 converts the long-wavelength light component G <b> 2 (approximately 550 nm or more) in wavelength. The polarization plane is rotated by 90 degrees, and the light component G1 having a shorter wavelength (approximately 550 nm or less) is emitted to the separation / synthesis PBS 21 as P-polarized light as S-polarized light.
[0036]
Of the light components G1 and G2 incident on the separation / synthesis PBS 21, the light component G1 having a shorter wavelength of the P-polarized light is transmitted through the PBS reflection film and is incident on the first reflection type liquid crystal modulation element (G1 element) 23. Here, the plane of polarization is controlled according to the image and reflected. At this time, in a bright image, the plane of polarization is rotated to be S-polarized light, and a dark image is reflected as P-polarized light. The image light whose polarization plane is controlled by the first reflection type liquid crystal modulation element (G1 element) 23 is reflected by the PBS reflection surface of the separation / combination PBS 21 and travels to the color combining section 4. The reflected light which remains P-polarized without being controlled in the polarization plane by the first reflection type liquid crystal modulation element (G1 element) 23 passes through the PBS reflection surface of the separation / combination PBS 21 and further passes through the color component separation section 1. The light is transmitted and finally returned to the lamp 51.
[0037]
Of the G component light incident on the separating / combining PBS 21, the other component G2 having a longer wavelength of the S-polarized light is reflected by the PBS reflecting surface of the separating / combining PBS 21, and the second reflective liquid crystal modulator ( G2 element) 24, where the plane of polarization is controlled according to the image and reflected. At this time, the plane of polarization is rotated to P-polarized light in a bright image, and is reflected as S-polarized light in a dark image.
[0038]
The image light whose polarization plane is controlled by the second reflection type liquid crystal modulation element (G2 element) 24 passes through the PBS reflection surface of the separation / combination PBS 21 and goes to the color combining section 4. On the other hand, the light reflected by the second reflection type liquid crystal modulation element (the element for G2) 24 while the polarization plane is not rotated and remains S-polarized light is reflected by the PBS reflection plane of the separation / combination PBS 21, The polarization plane is rotated by 90 degrees by the second color polarizer 22 to be P-polarized light, transmitted through the color component separation unit 1, and finally returned to the lamp 51.
[0039]
Here, a color polarizer having the spectral characteristics shown in FIG. 4 is applied to the first color polarizer 12. In FIG. 4, cross-polarizers indicated by a solid line I are spectral characteristics of output light when a polarizer and an analyzer are arranged on a cross via a wavelength-selective polarization converter and measured. On the other hand, parallel polarizers indicated by a dotted line II are spectral characteristics of output light when a polarizer and an analyzer are arranged and measured in parallel. From the figure, it can be seen that the polarization plane in the green light wavelength range of 500 nm to 590 nm is rotated by 90 degrees.
[0040]
Further, the second color polarizer 22 has the spectral characteristics shown in FIG. As can be seen from the spectral characteristic III of the cross-polarizer and the spectral characteristic IV of the parallel-polarizer in FIG. I understand.
[0041]
It is also possible to produce a wavelength-selective polarization conversion means having a function of rotating the plane of polarization of only red light or only a short wavelength range of blue light and green light by 90 degrees. The wavelength-selective polarization conversion means is described in detail in US Pat. No. 5,751,384.
[0042]
Next, the imaging system of FIG. 2 will be described in detail. FIG. 6 is a configuration diagram illustrating the imaging system of FIG. 2, the same components as those of FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 6, unnecessary optical components are not shown in the description of the imaging system. In FIG. 6, the reflected image light from the first and second reflective liquid crystal modulation elements 23 and 24 toward the color synthesizing unit 4 is separated by the synthesizing PBS 41 in the color synthesizing unit 4 into a second color component separation. The light is combined with the R and B image lights (description omitted) that have passed through the combining unit 3, and is formed on the screen 7 via the projection lens 6.
[0043]
FIG. 7 is a schematic diagram in which a part of the pixels formed on the screen 7 is enlarged. The image formation position is made to match each pixel of the R component and the B component and the pixel of the G1 component which is one of the G components, and the remaining G2 component pixels are 画素 pixel with respect to each pixel of the G1 component and the like. The first and second reflective liquid crystal modulation elements 23 and 24 are set so as to be shifted in the horizontal direction and the vertical direction of the formed image (screen) by the pitch. Although FIG. 7 shows only the pixel positions of the G1 and G2 components, the pixel positions of the R and B components are the same as the pixel positions of the G1 component. In FIG. 7, for convenience, numbers are given assuming that the top row is m rows in the horizontal direction and that the leftmost column is n columns in the vertical direction.
[0044]
When the primary color light components modulated and reflected by the projection type liquid crystal modulation element and reflected by the reflection type liquid crystal modulation element are imaged on a screen via a projection optical system, in FIG. Pixels are shifted by 1/2 pixel pitch in both the horizontal direction and the vertical direction of the formed image with respect to each pixel of the B component. However, the pixels are shifted by 1/2 pixel pitch only in the horizontal direction. You may. Further, the pixels of the R component and the B component may not be coincident with the pixels of the G1 component, but may be arranged at intermediate positions between the pixels of the G1 component and the G2 component.
[0045]
According to the liquid crystal projector having the projection unit of the first embodiment of the present invention described with reference to FIGS. 2 to 7, four reflection type liquid crystal modulation elements 23, 24, 33, and 34 are provided in one projection unit. , And among the three primary color lights, green light having high resolution due to human visual characteristics is divided into a short wavelength range component G1 and a long wavelength range component G2, and a total of two corresponding reflective liquid crystal modulation elements are respectively provided. 23 and 24, which are modulated by the projection image and the pixel arrangement is shifted by a half pixel pitch in both the horizontal and vertical directions, so that a high-definition color image with a small configuration can be obtained. it can.
[0046]
Further, according to the present embodiment, the present invention is applied to a system in which the aspect ratio of each of the four reflective liquid crystal modulation elements 23, 24, 33, and 34 is 4: 3, and the image is converted into a 16: 9 image by an anamorphic lens. In this case, the green light region is divided into a short-wavelength band component G1 and a long-wavelength band component G2, and the divided light is incident on the corresponding two reflection-type liquid crystal modulation elements 23 and 24, and is modulated by a projected image. Thus, a high-definition image projection system can be constructed in a small size and at low cost.
[0047]
Next, a second embodiment of the projection unit in FIG. 1 will be described. FIG. 8 shows a configuration diagram of a second embodiment of the projection unit in FIG. 2, the same components as those in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof will be omitted. The basic component arrangement and functions of the second embodiment of the projection unit shown in FIG. 8 are the same as those of the first embodiment of the projection unit shown in FIGS. The characteristics of the polarizers 12, 22, 32, 42, and 43 are changed, and they are color polarizers 13, 25, 35, 45, and 46, respectively.
[0048]
8, the white non-polarized light emitted from the lamp 51 is incident on the color polarizer 13 in the light component separation unit 1 ′ as S-polarized light by the polarizer 52. The color polarizer 13 rotates the polarization planes of the red light component R and the green light long-wavelength range component (approximately 550 nm or more in wavelength) G2 of the incident S-polarized white light by 90 degrees, and changes the polarization plane to P-polarized light. And Accordingly, the P-polarized red light component R and the green light long wavelength range component G2 pass straight through the color component separating PBS 11 and enter the first color separating / combining unit 2 '.
[0049]
In the first color separation / synthesis unit 2 ′, a second color polarizer 25 that rotates the wavelength range of the green component of the incident P-polarized light by 90 degrees is provided, and the long wavelength range of the green light is provided. The polarization plane of the component G2 is rotated by 90 degrees to be S-polarized light, and the incident red light component R is incident on the separation / combination PBS 21 as it is.
[0050]
The long-wavelength component G2 of the green light incident on the PBS 21 for separation / combination is reflected by the PBS reflection surface and is incident on the second reflection type liquid crystal modulation element (G2 element) 24 to control the polarization plane according to the image. Is reflected. At this time, in a bright image, the plane of polarization is rotated to be P-polarized light, and a dark image is reflected as S-polarized light. The P-polarized image light whose polarization plane is rotated passes through the PBS reflection surface of the PBS 21 for separation / combination, and travels toward the color combining unit 4 '. On the other hand, the polarization plane is not rotated by the second reflection-type liquid crystal modulation element (G2 element) 24, and the G2 of the reflected light which remains S-polarized light is reflected by the PBS reflection surface of the separation / combination PBS 21 to form a color component. The light passes through the separation unit 1 ′ and is finally returned to the lamp 51.
[0051]
The red light component R of the other P-polarized light of the light incident on the separation / combination PBS 21 passes through the color polarizer 25 as it is, and further passes through the PBS reflection surface of the separation / combination PBS 21, and And is reflected by the polarization plane controlled according to the image. At this time, in a bright image, the plane of polarization is rotated to be S-polarized light, and a dark image is reflected as P-polarized light.
[0052]
The S-polarized light (red light component R of a bright image) whose polarization plane is rotated by 90 degrees by the first reflection type liquid crystal modulation element (R element) 23 is reflected by the PBS reflection surface of the separation / synthesis PBS 21 to produce a color. Head to the combining unit 4 '. On the other hand, the reflected light (red light component R of a dark image) that remains the P-polarized light without rotating the polarization plane by the first reflective liquid crystal modulation element (R element) 23 is reflected by the PBS 21 of the separation / combination PBS 21. The light passes through the surface, further passes through the color component separation unit 1 ′, and is finally returned to the lamp 51.
[0053]
On the other hand, the blue light component B and the short-wavelength component G1 of green light, which are irradiated from the lamp 51, enter the light component separation unit 1 as S-polarized light by the polarizer 52, and the polarization plane of which is not rotated by the color polarizer 13, are colored. The light is reflected by the PBS reflection surface of the component separation PBS 11 and enters the second color separation / combination unit 3 '.
[0054]
In the second color separation / synthesis unit 3 ′, since the third color polarizer 35 that rotates the wavelength range of the green light of the incident S-polarized light by 90 degrees is installed, the color component separation unit 1 ′. Out of the S-polarized light incident from the light source, only the short wavelength band component G1 of green light is rotated by 90 degrees by the color polarizer 35 to be P-polarized light, and the remaining blue light component R is rotated by the polarization plane. Without going to the separation / synthesis PBS 31 as it is.
[0055]
The short-wavelength component G1 of the green light that has entered the PBS 31 for separation / synthesis passes through the PBS reflection surface, enters the third reflection-type liquid crystal modulation element (element for G1) 33, and changes the polarization plane according to the image. Controlled and reflected. At this time, in a bright image, the plane of polarization is rotated to be S-polarized light, and a dark image is reflected as P-polarized light. The S-polarized light (the short wavelength component G1 of the green light of a bright image) whose polarization plane is rotated by 90 degrees by the third reflective liquid crystal modulator (R element) 33 is reflected by the PBS reflection surface of the PBS 31 for separation and synthesis. The light is reflected and goes to the color synthesis unit 4 '.
[0056]
On the other hand, reflected light (short wavelength component G1 of green light of a dark image) that remains P-polarized without rotating the plane of polarization by the third reflective liquid crystal modulation element (element for G1) 33 is used for separation and synthesis. The light passes through the PBS reflection surface of the PBS 31 and further passes through the color component separation unit 1 ′, and is finally returned to the lamp 51.
[0057]
The blue light component B of the other S-polarized light of the light incident on the PBS 31 for separation / combination is reflected by the PBS reflection surface of the PBS 31 for separation / synthesis, and the fourth reflection type liquid crystal modulation element (the element for B) ) 34, and the light is reflected with its polarization plane controlled according to the image. At this time, in a bright image, the plane of polarization is rotated to be P-polarized light, and a dark image is reflected as S-polarized light.
[0058]
The P-polarized light (blue light component B of a bright image) whose polarization plane is rotated by 90 degrees by the fourth reflection type liquid crystal modulation element (element for B) 34 passes through the PBS reflection surface of the separation / combination PBS 31 to generate a color. It goes to the component synthesis unit 4 '. On the other hand, the reflected light (the blue light component B of the dark image) which remains the S-polarized light without the polarization plane being rotated by the fourth reflective liquid crystal modulation element (the element for B) 34 is reflected by the PBS 31 of the PBS 31 for separation and synthesis. The light is reflected by the surface, further passes through the color component separation unit 1 ′, and is finally returned to the lamp 51.
[0059]
Since the color polarizers 45 and 46 of the color component synthesizing unit 4 ′ have the same characteristics as the color polarizers 42 and 43, the color polarizer 45 outputs the length of the S-polarized green light. The wavelength band component G2 and the red light component R are taken out, are incident on the PBS 41 for synthesis, and are reflected on the PBS reflection surface. On the other hand, the short-wavelength band component G1 of the green light which is converted into P-polarized light from the color polarizer 46, respectively. And the blue light component B are taken out, enter the combining PBS 41, pass through the PBS reflection surface, are combined respectively, and their polarization planes are adjusted by the color polarizer 44 (not shown), and then the screen (through the projection lens). (Either is not shown).
[0060]
The pixel positions of the light components G1, G2, R, and B formed on the screen are the same as the example described with reference to FIG. Sets the first and second reflective liquid crystal modulation elements 23 and 24 so as to be shifted by a half pixel pitch in both the horizontal and vertical directions. This embodiment also has the same features as the first embodiment.
[0061]
Next, a third embodiment of the present invention will be described. FIG. 9 shows a configuration diagram of a third embodiment of the projection unit in FIG. 2, the same components as those of FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. In the third embodiment shown in FIG. 9, the illumination light source unit 5 shown in FIG. 2 is arranged above the light component separating PBS 11 so that light incident on the light component separating PBS 11 and light emitted from the light component combining PBS 41 are emitted. The direction is orthogonal. In this case, it can be easily realized by changing the polarization plane of the light emitted from the light source unit 5 to that shown in FIG. 2 or changing the characteristics of the first color polarizer 12. This embodiment also has the same features as the first embodiment.
[0062]
Next, a fourth embodiment of the present invention will be described. FIG. 10 shows a configuration diagram of a fourth embodiment of the projection unit in FIG. 2, the same components as those of FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 10, the projection unit according to the fourth embodiment includes a color component separation unit 1, a first color component separation / synthesis unit 2, a second color component separation / synthesis unit 3, and a color unit. It comprises a component synthesizing section 8, an illumination light source section 5, and a projection lens 6.
[0063]
The first color separation / synthesis unit 2 includes a phase plate (λ / 4 phase plate) 26, a separation / synthesis PBS 21, and a PBS 21 for separation / synthesis of incident light, which are disposed to face the main surface of the color separation unit 1 side. A first reflection type liquid crystal modulation element 23 is provided on the main surface side which reaches through the light, and a second reflection type liquid crystal modulation element 24 is provided on the main surface side which reflects on the reflection surface of the separation / combination PBS 21. .
[0064]
The P-polarized light transmitted through the separation PBS 11 is converted into a circularly-polarized light by a λ / 4 (λ is a wavelength) phase plate 26 and is incident on the separation / combination PBS 21. The S-polarized light component among the light components converted into circularly polarized light by the phase plate 26 is reflected by the reflection surface of the separation / combination PBS 21 and is incident on the second reflective liquid crystal modulation element 24. On the other hand, among the light components that have been converted into circularly polarized light by the phase plate 26, the P-polarized light component passes through the separation / combination PBS 21 and enters the first reflective liquid crystal modulation element 23.
[0065]
The light components incident on the first reflective liquid crystal element 23 and the second reflective liquid crystal modulation element 24 are reflected with their polarization controlled in accordance with the image to be projected. In a device having a bright projected image, the incident light is reflected by being rotated by 90 degrees, and in a dark device, the polarization plane is reflected as it is. That is, the P-polarized light incident on the first reflection type liquid crystal modulation element 23 is reflected as S-polarized light according to the image, reflected on the reflection surface of the separating / combining PBS 21, and is incident on the color component combining unit 4. Is done. The P-polarized light component whose polarization has not been controlled passes through the reflection surface of the separation / combination PBS 21 and is returned to the illumination light source unit 5.
[0066]
The S-polarized light that has entered the second reflective liquid crystal modulation element 24 is reflected as P-polarized light according to the image, passes through the reflection surface of the separation / synthesis PBS 21, and enters the color component synthesis unit 4. Is done. The S-polarized light component whose polarization has not been controlled is reflected on the reflection surface of the separation / combination PBS 21 and returned to the light source unit 5.
[0067]
The color component synthesizing unit 8 includes a dichroic mirror prism 81. The dichroic mirror prism 81 reflects the image light incident from the first color component separation / synthesis unit 2 and transmits and synthesizes the light incident from the second color component separation / synthesis unit 3 to the projection lens 6. An image is projected and projected on a guiding screen (not shown).
[0068]
Next, the color separation / combination method of FIG. 10 will be described in detail with reference to the configuration diagram of FIG. 11, the same components as those in FIG. 10 are denoted by the same reference numerals. In FIG. 11, the white light emitted from the lamp 51 is non-polarized light, and only the S-polarized light component is transmitted by the polarizer 52 and guided to the color component separation unit 1.
[0069]
In the color component separation unit 1, the green light component G of the white light is rotated by 90 degrees in the polarization plane by the color polarizer 12 to become P-polarized light, and is incident on the color component separation PBS 11. On the other hand, the red light component R and the blue light component B are incident on the color component separating PBS 11 as S-polarized light without rotating the plane of polarization by the color polarizer 12.
[0070]
In the color component separating PBS 11, the red light component R and the blue light component B, which are incident as S-polarized light, are reflected by the PBS reflection surface and emitted in a direction orthogonal to the incident light, and the second color separating / combining unit. 3 enters the color polarizer 32. On the other hand, the green light component G converted into the P-polarized light by the color polarizer 12 passes through the PBS reflection surface of the color component separating PBS 11 and directly proceeds to the first color component separating / combining unit 2.
[0071]
The first color separation / synthesis unit 2 converts the incident green light component G of the P-polarized light into circularly-polarized light via the λ / 4 phase plate 26, and then changes the green light component G on the PBS reflection surface of the separation / synthesis PBS 21. A direction in which the first green light component Ga of the P-polarized light component and the second green light component Gb of the S-polarized light component are separated into two green light components whose polarization planes are different from each other by 90 degrees in the same wavelength range, and are orthogonal to each other. Out. The emitted first green light component Ga of the P-polarized light component passes through the PBS surface of the separation / synthesis PBS 21 and enters the first reflective liquid crystal modulation element 23, where the polarization surface is controlled according to the image and reflected. Is done.
[0072]
At this time, in a bright image, the plane of polarization is rotated to be S-polarized light, and a dark image is reflected as P-polarized light. The first green light component Ga of the S-polarized light whose polarization plane has been rotated by the bright image is reflected by the PBS reflection surface of the separation / combination PBS 21 and travels to the dichroic mirror prism 81 of the color combining section 8. The first green light component Ga that remains P-polarized light without rotating the polarization plane according to the image passes through the PBS reflection surface of the PBS 21 for separation / synthesis, and further passes through the phase plate 26 and the color component separation unit 1 sequentially. Then, it is finally returned to the lamp 51.
[0073]
The second green light component Gb of the other S-polarized light component separated on the PBS reflection surface of the separation / combination PBS 21 is reflected on the PBS surface of the separation / combination PBS 21, and the second reflection type liquid crystal modulation element 24. And the light is reflected with its polarization plane controlled according to the image. At this time, the plane of polarization is rotated to P-polarized light in a bright image, and is reflected as S-polarized light in a dark image. The second green light component Gb whose polarization plane has been rotated to become P-polarized light by the bright image passes through the PBS reflection surface of the separation / combination PBS 21 and travels toward the dichroic mirror prism 81 of the color combining section 8. The second green light component Gb, which remains in the S-polarized light without rotating the polarization plane according to the image, is reflected by the PBS reflection surface of the separation / combination PBS 21, passes through the phase plate 26, and further passes through the color component separation unit 1. Then, it is finally returned to the lamp 51.
[0074]
The red light component R and the blue light component B that have been converted into S-polarized light by the first color polarizer 12 are reflected by the reflection surface of the color separation PBS 11 and directly travel to the second color component separation / synthesis unit 3. In the second color separation / synthesis unit 3, the incident red light component R of the S-polarized light is rotated by 90 degrees by the second color polarizer 32 having the spectral characteristics shown in FIG. After that, the light is transmitted through the PBS reflection surface of the separation / synthesis PBS 31 and is incident on the third reflective liquid crystal modulation element 33.
[0075]
The third reflection type liquid crystal modulation element 33 is reflected with its polarization plane controlled according to the image. At this time, in a bright image, the plane of polarization is rotated to be S-polarized light, and a dark image is reflected as P-polarized light. The red light whose polarization plane is rotated by the third reflective liquid crystal modulation element 33 is reflected by the PBS reflection surface of the PBS 31 for separation / combination, and travels to the dichroic mirror prism 81 of the color combining section 8. The red light which is not rotated by the third reflection type liquid crystal modulation element 33 and remains P-polarized light passes through the PBS reflection surface of the separation / synthesis PBS 21, and the second color polarizer 32 changes the polarization surface. The light is rotated by 90 degrees, reflected by the reflection surface of the color component separating PBS 11, and finally returned to the lamp 51.
[0076]
Further, in the second color separation / combination unit 3, the incident blue light component B of the S-polarized light is directly incident on the separation / combination PBS 31 without rotating the polarization plane by the second color polarizer 32. Then, the light is reflected by the PBS reflection surface and made incident on the fourth reflection type liquid crystal modulation element 34.
[0077]
In the fourth reflective liquid crystal modulation element 34, the polarization plane is controlled according to the image and reflected. At this time, in a bright image, the plane of polarization is rotated to be P-polarized light, and a dark image is reflected as S-polarized light. The blue light whose polarization plane has been rotated passes through the PBS reflection surface of the PBS 31 for separation / combination, and travels to the dichroic mirror prism 81 of the color combining section 8. On the other hand, blue light that remains S-polarized without rotating the polarization plane is reflected by the PBS reflection surface of the separation / combination PBS 31, passes through the second color polarizer 32, and is reflected by the color component separation PBS 11. The light is reflected by the surface and finally returned to the lamp 51.
[0078]
The dichroic mirror prism 81 constituting the color component synthesizing unit 8 is a wavelength-selective prism that reflects or transmits according to the wavelength range of the incident light, and has a wavelength of 500 nm incident on the first main surface of the two main surfaces. The green light component Ga and the green light component Gb of 590 nm are reflected, and the blue light component B having a wavelength of 420 nm to 500 nm and the red light component R of a wavelength of 590 nm to 680 nm incident on the second main surface are transmitted to each primary color. The light components Ga, Gb, B, and R are combined and emitted in the same direction, that is, toward the projection lens 6 side.
[0079]
Next, the imaging systems of FIGS. 10 and 11 will be described in detail. FIG. 12 is a configuration diagram illustrating the image forming system of FIGS. 10 and 11. In the figure, the same components as those in FIGS. 10 and 11 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 12, unnecessary optical components are not shown in the description of the imaging system. In FIG. 12, the green light components Ga and Gb, which are the modulated reflected light from the first and second reflective liquid crystal modulators 23 and 24 toward the dichroic mirror prism 81 in the color synthesizing unit 8, are described above. As described above, the light is reflected by the reflection surface of the dichroic mirror prism 81 and is synthesized with the red light component R and the blue light component B, which are the modulated reflected light from the third and fourth reflective liquid crystal modulation elements 33 and 34, An image is formed on a screen 7 via a projection lens 6.
[0080]
At this time, the arrangement of the pixels of the primary color light components of Ga, Gb, R, and B formed on the screen 7 is the same as in FIG. However, in the present embodiment, the pixels of the green light components Ga and Gb in the same wavelength range are arranged at pixel positions G1 and G2 in FIG. 7, that is, at a pixel pitch of 1/2 each in the horizontal and vertical directions of the formed image. Staggered. Also in this embodiment, the pixel positions of the R component and the B component are arranged at the same positions as the pixel positions of the Ga component. Note that the Gb component pixels may be arranged so as to be shifted from the Ga component, R component, and B component pixels by a half pixel pitch only in the horizontal direction of the formed image. Further, the pixels of the R component and the B component may not be coincident with the pixels of the Ga component, but may be arranged at intermediate positions between the pixels of the Ga component and the Gb component. As a result, this embodiment has the same features as those of the above-described embodiments. Furthermore, in this embodiment, since the number of color polarizers is reduced by using the phase plate 26 and the dichroic mirror prism 81 as compared with the first to third embodiments, the configuration is inexpensive. In addition, the dichroic mirror prism 81 has a feature that there is a space and that a countermeasure against cooling against a temperature rise due to illumination light is easy.
[0081]
Next, a fifth embodiment of the present invention will be described. FIG. 13 shows a configuration diagram of a fifth embodiment of the projection unit in FIG. In the figure, the same components as those in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 13, the projection unit according to the fifth embodiment includes a color component separation unit 9, a first color component separation / synthesis unit 2, a second color component separation / synthesis unit 3, and a color unit. It comprises a component synthesizing section 8, an illumination light source section 5, and a projection lens 6. This embodiment is characterized in that the color component separation section 9 is constituted by a dichroic mirror 14 which is a wavelength selective mirror, and the color component synthesis section 8 is constituted by a dichroic prism 82.
[0082]
In this embodiment, the dichroic mirror 14 reflects only the green light component having a wavelength of 500 nm to 590 nm out of the light components incident as S-polarized light, enters the phase plate 26, and emits blue light having a wavelength of 420 nm to 500 nm. The wavelength selection is made to transmit the light component and the red light component having a wavelength of 590 nm to 680 nm and enter the color polarizer 32. Like the dichroic mirror prism 81, the dichroic prism 82 has a wavelength selectivity that reflects a green light component and transmits a blue light component and a red light component.
[0083]
This embodiment also performs the same operation as that described with reference to FIG. 11, and can form a high-definition color image on a screen via the projection lens 6, which is the same as the above-described fourth embodiment. It has the features of The same operation is performed even if the dichroic mirror 14 is a dichroic prism.
[0084]
Next, a sixth embodiment of the present invention will be described. FIG. 14 shows a configuration diagram of a sixth embodiment of the projection unit in FIG. In the figure, the same components as those in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted. In the sixth embodiment shown in FIG. 14, the illumination light source unit 5 in FIG. 10 is arranged in the upward direction in the drawing of the light component separating PBS 11, and the incident light to the light component separating PBS 11 and the dichroic light component are combined. The light emitted from the mirror prism 81 is orthogonal to the direction. In this case, it can be easily realized by changing the polarization plane of the light emitted from the illumination light source unit 5 to that shown in FIG. 10 or changing the characteristics of the first color polarizer 12. This embodiment also has the same features as the above-described fifth embodiment.
[0085]
The present invention is not limited to the above embodiment. For example, the light emitted from the illumination light source unit 5 has been described as S-polarized light. An operation similar to that of the above-described embodiment is performed only by making the characteristics opposite (opposite). Further, an analyzer composed of a wave plate (λ / 4 plate) and a polarizer is inserted between the sixth color polarizer 44 and the projection lens 6 to prevent flare due to unnecessary reflected light, and the reflected light is transmitted to the liquid crystal modulator. There is no harm in returning to Japan and preventing any adverse effects. The pixel positions of the red light component and the blue light component are set so that the reflective liquid crystal modulation elements 23, 24, 33, and 34 are displayed at the same positions as the pixel positions of the green light component in the long wavelength region. May be set.
[0086]
【The invention's effect】
As described above, according to the present invention, each pixel of two green light components having high sensitivity in human visual recognition characteristics is divided into a pixel at a half pixel pitch in the horizontal direction of the formed image or in a horizontal and vertical direction. Since the display is performed at a pixel position shifted by 1/2 pixel pitch, the resolution in the horizontal direction or both the horizontal direction and the vertical direction can be increased, and without using a large reflective liquid crystal modulation element, One projection unit can have a compact configuration using four reflective liquid crystal modulation elements.
[0087]
According to the present invention, when a reflective liquid crystal modulator having an aspect ratio of 4: 3 is used and a system for converting the image to a 16: 9 image with an anamorphic lens is constructed, the two-divided green color is used. By driving light separately by two reflection-type liquid crystal modulation elements, a small-sized and inexpensive high-definition image projection system can be constructed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of a liquid crystal projector of the present invention.
FIG. 2 is a configuration diagram of a first embodiment of the projection unit in FIG. 1;
FIG. 3 is a configuration diagram of a main part of FIG. 2;
FIG. 4 is a spectral characteristic diagram of an example of a color polarizer used in a color component separation section according to the present invention.
FIG. 5 is a spectral characteristic diagram of an example of a color polarizer used in a first color component separation / generation unit in the present invention.
FIG. 6 is a configuration diagram illustrating the imaging system of FIG. 2;
FIG. 7 is an enlarged schematic view of a part of a pixel imaged on a screen according to the present invention.
FIG. 8 is a configuration diagram of a second embodiment of the projection unit in FIG. 1;
FIG. 9 is a configuration diagram of a third embodiment of the projection unit in FIG. 1;
FIG. 10 is a configuration diagram of a fourth embodiment of the projection unit in FIG. 1;
11 is a configuration diagram illustrating a method of color separation / combination in FIG.
FIG. 12 is a configuration diagram illustrating the image forming systems of FIGS. 10 and 11;
FIG. 13 is a configuration diagram of a fifth embodiment of the projection unit in FIG. 1;
FIG. 14 is a configuration diagram of a sixth embodiment of the projection unit in FIG. 1;
[Explanation of symbols]
1, 1 ', 9 color component separation unit
2, 2 'first color component separation / combination unit
3, 3 'second color component separation / combination unit
4, 4 ', 8 color component synthesis unit
5 Light source
6 Projection lens
7 Screen
11 Polarization beam splitter for color separation (PBS)
12, 13, 22, 25, 32, 35, 42, 45, 46 color polarizer
14 dichroic mirror
21, 31 Polarizing beam splitter (PBS) for separation and synthesis
23, 24, 33, 34 reflective liquid crystal modulator
26 λ / 4 phase plate
41 Combination Polarizing Beam Splitter (PBS)
81 dichroic mirror prism
82 dichroic prism
G1 Green light component in short wavelength range
G2 Long wavelength green light component
Ga, Gb Green light component divided into two
R red light component
B Blue light component

Claims (2)

An illumination light source for emitting white light;
The white light emitted from the illumination light source unit is converted into a green light component having a first polarization plane and a red light component having a second polarization plane whose polarization plane differs from the first polarization plane by 90 degrees. And a color component separation unit that separates into primary color light components composed of blue light components and emits light in directions orthogonal to each other.
The green light component is separated into a short-wavelength green light component and a long-wavelength green light component whose polarization planes are different from each other by 90 degrees, and the short-wavelength green light component is projected by a first reflection type liquid crystal modulation element by a projection image. The light is modulated and reflected, and the long wavelength green light component is modulated and reflected by the second reflection type liquid crystal modulation element according to the projection image, and is modulated from the first and second reflection type liquid crystal modulation elements, respectively. A first separation / synthesis unit that emits the reflected short-wavelength band green light component and long-wavelength band green light component in directions perpendicular to the incident direction of the green light component,
The primary color light component consisting of the red light component and the blue light component is separated into a red light component and a blue light component whose polarization planes are different from each other by 90 degrees, and the red light component is projected by a third reflective liquid crystal modulation element. The blue light component is modulated and reflected by the fourth reflection type liquid crystal modulation element according to the projection image, and the blue light component is modulated and reflected by the third and fourth reflection type liquid crystal modulation elements, respectively. A second separation / synthesis unit that emits the red light component and the blue light component, respectively, in a direction orthogonal to an incident direction of the primary color light component;
The polarization planes of the short wavelength green light component and the long wavelength green light component emitted from the first separation / combination unit are respectively converted into the first or second polarization plane, and the After converting each of the polarization planes of the red light component and the blue light component emitted from the separation / combination unit 2 into either the first or second polarization plane, the four primary color light components are combined. A color component synthesizing unit that emits light in the same direction;
A projection optical system for enlarging and projecting the combined light combined by the color component combining section, wherein at least the first and second reflective liquid crystal modulators are provided with the first and second reflective liquid crystal modulators. When each green light component of the short wavelength region and the long wavelength region modulated by the element is imaged on a screen via the projection optical system, a half pixel pitch in the horizontal direction of the formed image, or A liquid crystal projector characterized in that the liquid crystal projector is set so as to be displayed at a pixel position shifted by a half pixel pitch in the direction and the vertical direction, respectively. An illumination light source for emitting white light;
The white light emitted from the illumination light source unit is converted into a green light component having a first polarization plane and a red light component having a second polarization plane whose polarization plane differs from the first polarization plane by 90 degrees. And a color component separation unit that separates into primary color light components composed of blue light components and emits light in directions orthogonal to each other.
The green light component is divided into first and second green light components having polarization planes different from each other by 90 degrees, and the first green light component is modulated by a first reflective liquid crystal modulation element according to a projected image. The second green light component is reflected and modulated by the second reflective liquid crystal modulation element according to the projection image and reflected, and is modulated and reflected from the first and second reflective liquid crystal modulation elements, respectively. A first separation / combination unit that emits the first and second green light components in a direction orthogonal to an incident direction of the green light component;
The primary color light component composed of the red light component and the blue light component is separated into a red light component and a blue light component whose polarization planes are different from each other by 90 degrees, and the separated red light component is a third reflective liquid crystal modulator. The blue light component modulated and reflected by the projection image, and the separated blue light component is modulated and reflected by the projection image in a fourth reflection type liquid crystal modulation element, and is reflected from the third and fourth reflection type liquid crystal modulation elements. A second separation / synthesis unit that emits the red light component and the blue light component that are modulated and reflected, respectively, in a direction orthogonal to the incident direction of the primary color light component;
The first and second green light components emitted from the first separation / synthesis unit and the red light component and blue light component emitted from the second separation / synthesis unit according to wavelength ranges, respectively. A color component synthesizing unit that respectively synthesizes these four primary color light components and emits them in the same direction by transmitting or reflecting the
A projection optical system for enlarging and projecting the combined light combined by the color component combining unit, wherein at least the first and second reflection type liquid crystal modulation elements include the first and second reflection type liquid crystal modulation devices. When the first and second green light components modulated by the elements are imaged on a screen via the projection optical system, a 1/2 pixel pitch in the horizontal direction of the formed image, or a vertical direction in the horizontal direction. A liquid crystal projector characterized in that the liquid crystal projector is set so as to be displayed at a pixel position shifted by a half pixel pitch in each direction.

Images