JP2016164665A - Projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection device that improves 3D image quality.SOLUTION: A projection device 1 includes a color synthesis unit 10, a polarization conversion unit 20, and a projection lens 30. The color synthesis unit 10 synthesizes each of rays of three primary R, G, B colors and outputs synthesized light. The polarization conversion unit 20 is located on an output side of the color synthesis unit 10 to convert a polarization state of each color ray of the synthesized light into an unpolarized state uniformly in all directions. The projection lens 30 projects output light from the polarization conversion unit 20. One selected from a wavelength-selective 1/2 wavelength plate that introduces a π phase shift to light of predetermined wavelengths, a uniaxial organic material having one optical axis, and a uniaxial crystal having one optical axis is used as the polarization conversion unit 20.SELECTED DRAWING: Figure 1

Description

  The present technology relates to a projection apparatus that performs video display.

  In recent years, LCD (Liquid Crystal Display) projectors having an active shutter 3D (dimensions) function have been developed.

  The active shutter method is one of the video display methods with perspective. The left-eye and right-eye images are alternately displayed, and the 3D glasses view is alternately displayed on the left and right in synchronization with the image switching. By blocking the light, parallax is produced and stereoscopic viewing is possible.

  On the other hand, it is more difficult to ensure the quality of the projector as described above that displays 3D images than the projector that displays 2D images. This is because, in the light of a certain polarization state reflected by the screen, only the polarization component in a specific direction is transmitted by the 3D glasses, and this polarization state greatly affects the 3D image quality (color unevenness, luminance drop). Because.

  Since 2D image display does not use 3D glasses, light enters the observer's pupil equally in any polarization state, and the polarization state after screen reflection does not affect the image quality. On the other hand, in an LCD projector or the like having an active shutter 3D function, it is important to consider the polarization state until it reaches 3D glasses.

  As a conventional technique, there has been proposed a projection display device that converts the polarization state of each color by making the light quantity ratio of RGB colors in the horizontal / vertical directions equal.

JP 2007-304607 A

  However, in a projector that displays a conventional 3D image, an appropriate polarization conversion process for improving 3D image quality has not been performed until the projection light of the projector is reflected by the screen and reaches the 3D glasses.

  For this reason, there has been a problem that uneven color of the 3D image can be seen without tilting the 3D glasses. In addition, there is a problem that color unevenness and luminance drop of a 3D image can be seen with the 3D glasses tilted.

  The present technology has been made in view of the above points, and eliminates the uneven color of the 3D image when the 3D glasses are not tilted, and the uneven color and the brightness drop of the 3D image when the 3D glasses are tilted. An object of the present invention is to provide a projection apparatus in which the 3D image quality is greatly improved by eliminating the above-described problem.

  In order to solve the above problems, a projection apparatus is provided. The projection device includes a color synthesis unit, a polarization conversion unit, and a projection lens. The color combining unit includes a color combining prism and a half-wave plate disposed on the green light incident side of the color combining prism, and combines the three primary color lights to emit combined light. The polarization conversion unit is disposed on the emission side of the color synthesis unit, and converts the polarization state of each color light of the combined light uniformly into a non-polarization state with respect to all directions. The projection lens projects the outgoing light from the polarization conversion unit. In addition, the polarization conversion unit is installed close to the incident surface side of the projection lens and follows the lens shift of the projection lens.

  3D image quality can be greatly improved.

It is a figure which shows the structural example of a projection apparatus. It is a figure which shows the change element of a polarization state. It is a figure which shows the color nonuniformity seen through 3D glasses. It is a figure which shows the color nonuniformity seen through 3D glasses. It is a figure which shows the example of an optical unit structure of a transmissive | pervious LCD system projector. It is a figure which shows the example of an optical unit structure of a reflection type LCD system projector. It is a figure which shows a wavelength selective half wavelength plate. It is a figure for demonstrating the characteristic of a wavelength selectivity 1/2 wavelength plate. It is a figure which shows a uniaxial organic material and a uniaxial crystal. It is a figure for demonstrating the characteristic of a uniaxial organic material and a uniaxial crystal. It is a figure which shows the polarization state by the phase difference of a uniaxial organic material and a uniaxial crystal. It is a figure which shows the structural example of a projection apparatus. It is a figure which shows the structural example of a projection apparatus. It is a figure which shows the structural example of a projection apparatus. It is a figure which shows the structural example of a projection apparatus. It is a figure which shows the structural example of a projection apparatus. It is a figure which shows the example of an installation form. It is a figure which shows the example of an installation form. It is a figure which shows the example of an installation form. It is a figure which shows the projection image of a projection apparatus.

  Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of a projection apparatus. The projection device 1 includes a color synthesis unit 10, a polarization conversion unit 20, and a projection lens 30.

  The color synthesizing unit 10 synthesizes light of the three primary colors R (red), G (green), and B (blue) and emits synthesized light. The polarization conversion unit 20 is arranged on the emission side of the color combining unit 10 and converts the polarization state of each color light of the combined light into a non-polarized state that is uniform in all directions. The projection lens 30 projects the light emitted from the polarization converter 20 onto the screen.

  Here, the polarization conversion unit 20 includes a wavelength-selective half-wave plate that shifts the phase by π with respect to a predetermined wavelength, a uniaxial organic material that is an organic material having one optical axis (optical axis), and an optical axis. One of the uniaxial crystals that has one crystal.

  By arranging such a polarization conversion unit 20 between the emission side of the synthesized light from the color synthesis unit 10 and the incident side of the projection lens 30, each color light of the synthesized light emitted by the color synthesis unit 10 The polarized light of the inner wavelength can be converted into polarized light different from each other for each wavelength, and a uniform non-polarized state can be obtained with no deviation in all directions.

  As described above, the projection apparatus 1 includes the color synthesis unit 10, the polarization conversion unit 20, and the projection lens 30, and the polarization conversion unit 20 changes the polarization state of each color light emitted from the color synthesis unit 10 in a uniform and omnidirectional manner. The projection lens 30 is configured to project light in a non-polarized state by converting to a polarized state.

  With this configuration, the projection light projected from the projection device 1 toward the screen 7 is in a uniform non-polarized state in all directions, and the light reflected by the screen 7 and incident on the observer's 3D glasses 2 is also included. A uniform non-polarized state is obtained in all directions.

  As a result, the color unevenness of the 3D image when the 3D glasses 2 are not tilted can be completely eliminated, and the color unevenness and luminance drop of the 3D image when the 3D glasses 2 are tilted can be completely eliminated. 3D image quality can be greatly improved.

  Next, problems to be solved by the present technology will be described in detail. FIG. 2 is a diagram showing a change element of the polarization state. The projection light from the projection lens 51 of the projection device (projector) 50 is reflected by the screen 7 and reaches the 3D glasses 2. The change element of the polarization state entering the 3D glasses 2 is mainly influenced by the following three.

(1) Polarization Unevenness Generated in Projector 50 Polarization unevenness generated in the projector 50 occurs between the color combining prism 52 and the projection lens 51 in the projector 50. In particular, it is generated by the projection lens 51, and uneven polarization occurs even if the projection lens 51 is a glass lens or a plastic lens.

  When the projection lens 51 is a glass lens, uneven polarization occurs due to the material, shape, AR (Anti Reflection) coating, etc. of the glass lens. In the case of a plastic lens, uneven polarization occurs due to the plastic lens material, shape, AR coating, molding conditions, and the like. Particularly in a plastic lens, a large amount of uneven polarization occurs.

(2) Reflected Polarization Characteristic of Screen 7 When the screen 7 is a silver screen in particular, the projection light is reflected while maintaining the incident polarization state, so that the polarization unevenness (1) generated in the projector 50 remains as it is. To affect. In addition, a screen with in-plane unevenness in polarization characteristics is directly affected by the following (3).

(3) Tilt angle of the 3D glasses 2 of the observer The tilt angle with respect to the polarization transmission axis of the 3D glasses 2 when assuming a normal use state is about ± 25 ° when the observer tilts the neck. When the observer tilts his / her neck and the tilt angle of the 3D glasses 2 reaches about ± 25 °, the polarization transmission direction of the 3D glasses 2 also changes. As a result, the 3D image quality also changes greatly.

The polarization state entering the 3D glasses 2 is changed by the polarization state changing element according to the above (1) to (3), and conventionally, the following two problems have mainly occurred.
(A) Uneven color of the 3D image can be seen without tilting the 3D glasses 2.
(B) In the state where the 3D glasses 2 are tilted, the color unevenness and the luminance drop of the 3D image can be seen.

  3 and 4 are diagrams showing color unevenness seen through 3D glasses. For example, when the background is white on the screen 7, color unevenness (shown by an ellipse) as shown in FIG. 3 may be observed. Further, for example, when the screen 7 has in-plane unevenness of the polarization characteristics, when the observer tilts his / her neck, a linear color unevenness as shown in FIG. 4 may be seen.

  In order to solve the conventional problems (a) and (b), it is necessary to solve by the above-described polarization state changing element (1). This is because the screen 7 to be installed cannot be designated for the observer (customer) in the polarization state changing element (2). Further, in the polarization state changing element (3), it is not practical to use dedicated 3D glasses in the standardization flow of the 3D glasses 2.

  Here, when solving with the polarization state changing element of (1), the problem (a) can be solved by the following methods (# 1) to (# 3).

  (# 1) The projection lens 51 using a glass lens is used (no plastic lens is used). However, in this case, even if the problem (a) can be solved, the problem (b) cannot be solved.

  (# 2) When the color synthesis prism 52 is of the SPS system, a wavelength selective half-wave plate (Color Select) is used between the projection lens 51 and the color synthesis prism 52. Then, in the order of RGB, S polarization / P polarization / S polarization is aligned with P polarization / P polarization / P polarization or S polarization / S polarization / S polarization. However, in this case, even if the problem (a) can be solved, the problem (b) cannot be solved.

  In general, in a color combining prism used in a projector, green light has a higher transmittance in the case of P-polarized light than in the case of S-polarized light, and therefore the SPS method is more dominant than the SSS method. . However, the SSS method is also used in order to align the RGB polarization after emission from the color synthesis prism.

  (# 3) The color synthesis prism 52 is set to the SSS system. However, in this case, even if the problem (a) can be solved, the problem (b) cannot be solved. Further, since the transmittance of G (Green) is greatly reduced, the 2D luminance is significantly reduced.

  Thus, for the problem (a), there are solutions (# 1) to (# 3) described above. However, the method (# 1) to (# 3) cannot solve the problem (b). This is because in any of the methods (# 1) to (# 3), the projection light from the projector 50 could not be converted into non-polarized light by simply aligning RGB with linearly polarized light in the same direction (this No depolarization has been found to be a solution).

  On the other hand, as a method for solving the problems (a) and (b), a wavelength-selective half-wave plate, a uniaxial organic material, or a uniaxial crystal is arranged on the projection side (outgoing stage) of the projection lens 51. A method of depolarizing the polarization state can be considered. By adopting such a configuration, it is possible to obtain good results with respect to both of the problems (a) and (b).

  However, even with such a configuration, color unevenness and luminance drop of a 3D image cannot always be completely eliminated. This is because when the polarization disturbance is too large, for example, particularly when a plastic lens is used as the projection lens, the amount of non-polarization is insufficient. In this case, a small amount of color unevenness / There was a drop in brightness.

  If a wavelength-selective half-wave plate, a uniaxial organic material, or a uniaxial crystal is arranged on the projection side of the projection lens 51, the projection light from the projection lens 51 can be made nearly non-polarized. However, in the case where a plastic lens having a large polarization disturbance is used for the projection lens 51, it is difficult to make the non-polarized light uniformly in all directions, even though the projection light can be brought close to the non-polarized light. It becomes a non-polarized state with. For these reasons, even with the above-described configuration, the color unevenness and the luminance drop cannot be completely eliminated.

  Although a solution method of increasing the thickness of the uniaxial organic material and the uniaxial crystal is also conceivable, there arises a problem that the focusing performance is deteriorated.

  The present technology has been made in view of such points, and the color unevenness of the 3D image when the 3D glasses 2 are not tilted is completely eliminated, and the color of the 3D images when the 3D glasses 2 are tilted. The present invention provides a projection apparatus 1 in which unevenness and a drop in luminance are completely eliminated and 3D image quality is greatly improved.

  Next, as an application example of the projection apparatus 1, a transmissive LCD projector and a reflective LCD projector will be described.

  FIG. 5 is a diagram showing an example of the configuration of an optical unit of a transmissive LCD projector. The transmissive LCD projector 100 includes a light source unit, an illumination optical system, a separation optical system, a light modulation element unit, a combining optical system, and a projection optical system.

  The light source unit includes a light source 101 and a reflector 102. The light source 101 is an HID (High Intensity Discharge) lamp such as an ultra-high pressure mercury lamp or a metal halide lamp, and emits white light. The light source 101 is disposed at the focal position of the reflector 102, and the white light emitted from the light source 101 is reflected by the reflector 102 to generate substantially parallel light. The reflector 102 has not only a parabolic shape but also an elliptical shape.

  The illumination optical system includes a UV (Ultra Violet) cut filter 111, fly-eye lenses 112-1 and 112-2, a polarization separation element 113, a wavelength plate unit (polarization modulation element) 114, and a condenser lens 115.

  The UV cut filter 111 is provided in front of the light source 101 and blocks passage of ultraviolet rays emitted from the light source 101. The fly-eye lenses 112-1 and 112-2 receive substantially parallel light reflected by the reflector 102 and emit it to the polarization separation element 113. The fly-eye lenses 112-1 and 112-2 make the illuminance of light incident on the light modulation element portion uniform.

  The polarization separation element 113 separates the incident light beam into a first polarization component and a second polarization component. For example, the polarization separation element 113 receives light including S-polarized light and P-polarized light, emits P-polarized light to the first region, and emits S-polarized light to the second region.

  The wave plate unit 114 aligns the polarization axis of the outgoing light from the polarization separation element 113 in a predetermined direction. For example, the wave plate unit 114 modulates P-polarized light incident on the first region into S-polarized light, and aligns the polarization axis with the S-polarized light incident on the second region.

  The condenser lens 115 receives and collects the light emitted from the wave plate unit 114. The white light emitted from the condenser lens 115 enters the separation optical system.

  The separation optical system separates incident light from the condenser lens 115 into RGB (red, green, blue). The separation optical system includes dichroic mirrors 121-1 and 121-2, reflection mirrors 122-1 to 122-3, relay lenses 123-1 and 123-2, and condenser lenses 124 R, 124 G, and 124 B.

  The dichroic mirrors 121-1 and 121-2 selectively transmit or reflect RGB light depending on the wavelength band. The dichroic mirror 121-1 transmits the light G in the green wavelength band and the light R in the red wavelength band, and reflects the light B in the blue wavelength band.

  The dichroic mirror 121-2 transmits the light R in the red wavelength band and reflects the light G in the green wavelength band. Thereby, the white light is color-separated into three colors of RGB. Note that the dichroic mirror is used in either the red separation or the blue separation.

  The reflection mirror 122-1 is composed of a total reflection mirror, reflects the light B in the blue wavelength band separated by the dichroic mirror 121-1, and guides it to the light modulation element 125 B. The reflection mirrors 122-2 and 122-3 are configured by total reflection mirrors, and reflect the light R in the red wavelength band separated by the dichroic mirror 121-2 and guide it to the light modulation element 125R.

  The relay lenses 123-1 and 123-2 correct the optical path length for the light R in the red wavelength band. The condenser lenses 124R, 124G, and 124B converge the light G in the green wavelength band, the light R in the red wavelength band, and the light B in the blue wavelength band, respectively.

  The light G in the green wavelength band, the light R in the red wavelength band, and the light B in the blue wavelength band emitted from the separation optical system respectively enter the light modulation elements 125R, 125G, and 125B.

  In front of the light modulation elements 125R, 125G, and 125B (on the light source side), there are incident-side polarizing plates 128R, 128G, and 128B. The green wavelength band light G, the red wavelength band light R emitted from the separation optical system, And the polarization components of the light B in the blue wavelength band are aligned.

  The light modulation elements 125R, 125G, and 125B spatially modulate light R in the red wavelength band, light G in the green wavelength band, and light B in the blue wavelength band, respectively. The exit-side polarizing plates 129R, 129G, and 129B transmit a predetermined polarization component of the spatially modulated light.

  The combining optical system has a color combining prism 126. The color synthesizing prism 126 is configured to transmit the light G in the green wavelength band and reflect the light R in the red wavelength band and the light B in the blue wavelength band in the direction of the projection optical system.

  The color synthesizing prism 126 is configured by, for example, joining a plurality of glass prisms (four substantially isosceles right-angled isosceles prisms), and the joining surface of each glass prism has a predetermined optical characteristic 2. Two interference filters are formed.

  The first interference filter reflects light B in the blue wavelength band and transmits light R in the red wavelength band and light G in the green wavelength band. The second interference filter reflects light R in the red wavelength band and transmits light G in the green wavelength band and light B in the blue wavelength band.

  Therefore, the RGB lights modulated by the light modulation elements 125R, 125G, and 125B are combined by the color combining prism 126 and enter the projection optical system.

  The projection lens 127 that is a projection optical system projects the image on the screen 7 by expanding the emitted light from the color synthesis prism 126 to a predetermined magnification.

  FIG. 6 is a diagram showing an example of the configuration of an optical unit of a reflective LCD projector. In the reflective LCD projector 200, the light source 201 is disposed at the focal position of the reflector 202, and the white light emitted from the light source 201 is reflected by the reflector 202 to generate substantially parallel light.

  A UV / IR (Ultra Violet / Infrared Rays) cut filter 211 receives substantially parallel light and blocks passage of ultraviolet rays and infrared rays. The reflector 202 has not only a parabolic shape but also an elliptical shape.

  The fly-eye lenses 212-1 and 212-2 make the illuminance of light uniform, and the PS converter (polarization conversion element) 213 aligns the polarization direction of random polarization of P polarization / S polarization. The main condenser lens 221 condenses the white illumination light whose polarization direction is aligned and uniformed by the PS converter 213.

  The dichroic mirror 222 separates the light LR in the red wavelength region and the light LGB in the green and blue wavelength regions. Note that the dichroic mirror is used in either the red separation or the blue separation. The reflection mirror 223 reflects the red light LR separated by the dichroic mirror 222.

  The reflection mirror 224 reflects the green and blue light LGB separated by the dichroic mirror 222. The dichroic mirror 225 reflects only the green wavelength region of the light LGB reflected by the reflection mirror 224, and transmits the blue wavelength region.

  The polarizing plate 226R transmits the red light LR, which is P-polarized light reflected by the reflection mirror 223, enters the reflective liquid crystal panel 230R, is spatially modulated by the reflective liquid crystal panel 230R, and is converted into S-polarized light. Is reflected and made incident on the color synthesis prism 240. A polarizing plate may be disposed on each of the RGB incident surfaces of the color synthesis prism 240.

  In the SSS method, the green light enters the color synthesis prism 240 as it is. In the SPS method, a half-wave plate is disposed on the incident side of the color synthesis prism 240, and green light is incident on the color synthesis prism 240 as P-polarized light.

  The polarizing plate 226G transmits green light LG, which is P-polarized light reflected by the dichroic mirror 225, to enter the reflective liquid crystal panel 230G, reflects the green light that is spatially modulated by the reflective liquid crystal panel 230G and converted to S-polarized light. Then, the light is incident on the color synthesis prism 240.

  The polarizing plate 226B transmits the blue light LB, which is P-polarized light that has passed through the dichroic mirror 225, is incident on the reflective liquid crystal panel 230B, is spatially modulated by the reflective liquid crystal panel 230B, and is converted into S-polarized light. Reflected and incident on the color synthesis prism 240.

  Note that optical lenses 227 to 229 are disposed on the incident side of each of the polarizing plates 226R, 226G, and 226B (a polarizing plate may be disposed between the optical lens 228 and the polarizing plate 226G).

  Here, the illuminance of the white light output from the light source 201 is made uniform by the fly-eye lenses 212-1 and 212-2, and is aligned with a predetermined polarization by the PS converter 213. The output light is oriented so as to irradiate the reflective liquid crystal panels 230R, 230G, and 230B by the main condenser lens 221, and then is converted into light in three wavelength bands by the dichroic mirrors 222 and 225 as color separation mirrors. To be separated.

  Each separated color light is incident on the reflective polarizing plate, and only light in one polarization direction is selected by the polarizing plates 226R, 226G, and 226B and is incident on the reflective liquid crystal panels 230R, 230G, and 230B. . RGB light is incident on the reflective liquid crystal panels 230R, 230G, and 230B.

  The reflective liquid crystal panels 230R, 230G, and 230B are supplied with a video signal having a color corresponding to the incident light, and rotate and modulate the polarization direction of the incident light according to the video signal. The modulated light emitted from the liquid crystal panel is incident on the polarizing plates 226R, 226G, and 226B again.

  Only the polarization component rotated by 90 degrees from the polarized light incident on the polarizing plates 226R, 226G, and 226B is selected and incident on the color combining prism 240. The color lights modulated by the three reflective liquid crystal panels are combined in the same direction by the color combining prism 240 and emitted. The outgoing combined light from the color combining prism 240 is projected and output onto the screen 7 by the projection lens 250.

  Next, the polarization conversion unit 20 in the projection apparatus 1 will be described. For the polarization conversion unit 20, any one of a wavelength selective half-wave plate, a uniaxial organic material, and a uniaxial crystal is used. Hereinafter, each characteristic will be described.

  FIG. 7 shows a wavelength selective half-wave plate. The wavelength-selective half-wave plate 21a has a first optical axis and a second optical axis orthogonal to the first optical axis, and converts light of a predetermined wavelength from a horizontal vibration to a vertical vibration. It has the characteristic of converting from vibration to transverse vibration and shifting the phase of a predetermined wavelength by π.

  FIG. 8 is a diagram for explaining the characteristics of the wavelength selective half-wave plate. When the linearly polarized incident light is incident on the wavelength selective half-wave plate 21a in parallel with the vibration direction of the first optical axis direction (at an angle of 0 ° or π), the phase is changed. A light beam parallel to the second optical axis is emitted after being shifted by π.

  Conversely, when the linearly polarized incident light is incident on the wavelength-selective half-wave plate 21a in such a way that its vibration direction is parallel to the second optical axis direction (at an angle of 0 ° or π). , The phase is shifted by π, and a light beam parallel to the first optical axis is emitted.

  Here, when the wavelength selective half-wave plate 21a is used in the projector 1, incident light is incident on the wavelength selective half-wave plate 21a in parallel with the first and second optical axes. Instead, it is preferable to enter linearly polarized light, circularly polarized light, elliptically polarized light or the like that is not parallel to the first and second optical axes.

  That is, the wavelength selection is performed such that each color light in the combined light emitted from the color combining unit 10 is received with polarized light that is not parallel to the first and second optical axes of the wavelength selective half-wave plate 21a. The light emitted from the chromatic half-wave plate 21a is close to “polarized light that varies depending on the wavelength” and is in a non-polarized state.

  In this way, the polarized light whose optical vibration direction is not parallel to the first and second optical axes passes through the wavelength selective half-wave plate 21a, so that the emitted light from the color combining unit 10 is The wavelength-selective half-wave plate 21a is converted into different polarized light for each wavelength to be in a non-polarized state.

  As described above, in the wavelength selective half-wave plate 21a, the more the incident polarized light deviates from the linearly polarized light in the direction of the first and second optical axes (for example, circularly polarized light, elliptically polarized light, For example, linearly polarized light rotated from the direction of the first and second optical axes), the emitted light is close to “polarized light that differs for each wavelength”. An optical member other than the wavelength-selective half-wave plate may be used as long as it has the property of “polarized light that varies depending on the wavelength”.

  Since the polarization direction of the incident light on the wavelength selective half-wave plate 21a only needs to deviate from the linearly polarized light in the directions of the first and second optical axes, there is an advantage that the installation range of the shaft is wide. . Further, it is not necessary to align the polarization direction (rotation direction) in advance at the incident stage of the wavelength selective half-wave plate 21a.

  FIG. 9 is a diagram showing a uniaxial organic material and a uniaxial crystal. The uniaxial organic material 21b is an organic material having one optical axis, and corresponds to, for example, a high retardation plate. The phase difference given to the incident light of the uniaxial organic material 21b is 10000 nm or more.

  The uniaxial crystal 21c is a crystal having one optical axis. For example, quartz (quartz), sapphire, calcite, magnesium fluoride, calcite and the like are applicable. The phase difference given to the incident light of the uniaxial crystal 21c is about 10000 nm (in the case of quartz, about 1 mm). On the other hand, the uniaxial organic material 21b and the uniaxial crystal 21c both have a slow axis of 45 °.

  FIG. 10 is a diagram for explaining the characteristics of a uniaxial organic material and a uniaxial crystal. The uniaxial organic material 21b and the uniaxial crystal 21c have a large refractive index for incident light having light vibration in the same direction as the slow axis shown in FIG. For incident light having vibration, the refractive index has a small characteristic.

  Therefore, when the incident polarized light is polarized light that vibrates (rotates) in a direction shifted by 45 ° with respect to the slow axis, the outgoing polarized light is unpolarized light. In addition, when the incident polarized light is polarized light that oscillates in a direction shifted by 0 ° or 90 ° with respect to the slow axis, the output polarized light is the same as the phase of the incident polarized light and does not change.

  On the other hand, when the incident polarized light is polarized light that vibrates in a direction other than the above with respect to the slow axis, the outgoing polarized light is emitted with a large polarization, and is far from the non-polarized state.

  Here, when the uniaxial organic material 21b or the uniaxial crystal 21c is used in the projection apparatus 1, the incident light beam is polarized linearly polarized light, circularly polarized light, elliptically polarized light that vibrates in a direction shifted by 45 ° with respect to the slow axis. Etc. are preferably incident.

  In this way, the polarized light oscillating in a direction shifted by 45 ° with respect to the slow axis passes through the uniaxial organic material 21b or the uniaxial crystal 21c, so that each color in the synthesized light emitted from the color synthesizing unit 10 is transmitted. The light is converted into mutually different polarized light for each wavelength by the uniaxial organic material 21b or the uniaxial crystal 21c to be in a non-polarized state.

  Note that the uniaxial organic material 21b and the uniaxial crystal 21c are most effective in a state where the polarized light immediately after emission from the color synthesis unit 10 is aligned. Among these, since the uniaxial crystal 21c (particularly quartz) has the following characteristics, the use of the uniaxial crystal 21c as the polarization converter 20 is highly effective.

(A1) Inexpensive compared to the wavelength-selective half-wave plate 21a and the uniaxial organic material 21b.
(A2) Since it is optical glass, it has high physical strength and high reliability.
(A3) Since it is not an organic material such as a sheet / film, the focusing performance does not deteriorate even if it is installed between the LCD and the projection lens.

  Next, the polarization state due to the phase difference between the uniaxial organic material 21b and the uniaxial crystal 21c will be described. FIG. 11 is a diagram showing a polarization state by a phase difference between a uniaxial organic material and a uniaxial crystal. The vertical axis indicates the polarization state, and the horizontal axis indicates the wavelength nm. In the figure, the curve k1 has a phase difference of 500 nm, the curve k2 has a phase difference of 1000 nm, the curve k3 has a phase difference of 2000 nm, and the curve k4 (jagged line) has a phase difference of 10,000 nm.

  Let us consider a case where there is a slow axis in the 45 ° direction with respect to the incident linearly polarized light and the phase difference amount is large (for example, 10,000 nm) (corresponding to the jagged line in the figure). When light passes through the slow axis, if the polarization state of a certain wavelength (for example, 550 nm) is linearly polarized light, the polarization state of the adjacent wavelength (for example, 501 nm) is elliptically polarized light that is close to linearly polarized light.

  In this way, when lights having different polarization states are added at each of the used wavelengths (about 430 to 700 nm), different polarizations are generated for each wavelength, so that an unpolarized state can be created.

  Therefore, when the uniaxial organic material 21b or the uniaxial crystal 21c is used for the polarization conversion unit 20, the polarization change amount per wavelength change increases when the conditions of the slow axis in the 45 ° direction and the high phase difference amount are met. It is possible to generate a more uniform unpolarized state.

  In addition, if the polarized light is linearly polarized light / elliptical polarized light / circularly polarized light in the S direction or P direction, it is particularly useful to create “polarized light that varies depending on wavelength” without distinction. Further, it is not necessary to align the polarization direction (rotation direction) in advance at the incident stage of the uniaxial organic material 21b or the uniaxial crystal 21c.

  Next, each version (arrangement pattern of optical members) of the polarization conversion process in the projection apparatus 1 will be described with reference to FIGS. FIG. 12 is a diagram illustrating a configuration example of the projection apparatus. The projection device 1-1 includes a color synthesis unit 10-1, a polarization conversion unit 20, and a projection lens 30.

  The color synthesis unit 10-1 includes a color synthesis prism 11 and a half-wave plate 12. The polarization conversion unit 20 applies any one of the wavelength selective half-wave plate 21a, the uniaxial organic material 21b, and the uniaxial crystal 21c described above with reference to FIGS.

  The half-wave plate 12 is disposed on the green light incident side of the color combining prism 11 of the SPS system, and converts green S-polarized light g1s to P-polarized light to generate green P-polarized light g1p. The general basic function of the half-wave plate is that when light passes through, a half wavelength (phase difference δ = 180 ° + N × 360 °) between two linearly polarized light (parallel component and vertical component). And is used mainly for the purpose of rotating the polarization plane to a required angle (N = 1, 2, 3,...).

  The color combining prism 11 combines the red S-polarized light r1s that is the S-polarized light of red light, the green P-polarized light g1p, and the blue S-polarized light b1s that is the S-polarized light of blue light to generate combined light.

  The polarization conversion unit 20 converts each polarization state of the red S-polarized light r1s, the green P-polarized light g1p, and the blue S-polarized light b1s emitted from the color combining prism 11 into a uniform non-polarized state with no bias in all directions. .

  The projection lens 30 receives the combined light emitted from the polarization conversion unit 20 in which each color light is in a non-polarized state, and magnifies and projects the combined light. Thereafter, the projection light in a uniform non-polarized state with no bias in all directions is projected onto the screen.

  When the wavelength selective half-wave plate 21 a is used as the polarization conversion unit 20, the first optical axis is 45 ° with respect to the incident polarized light and the second light on the emission side of the color synthesis prism 11. The optical axis is oriented in the direction of 135 °. Alternatively, the first optical axis is 135 ° and the second optical axis is 45 ° with respect to the incident polarized light.

  When the uniaxial organic material 21b or the uniaxial crystal 21c is used as the polarization conversion unit 20, the slow axis is 45 ° or 135 ° with respect to the incident polarized light on the emission side of the color synthesis prism 11. Arrange so that the optical axis faces.

  With the configuration of the projector 1-1 as described above, the polarization state of the incident light on the screen and the polarization state of the reflected light on the screen are in a uniform non-polarized state with no bias in all directions. As a result, the color unevenness of the 3D image when the 3D glasses are not tilted completely disappears, and the color unevenness and the luminance drop of the 3D images when the 3D glasses are tilted can be completely eliminated. Can be greatly improved.

  FIG. 13 is a diagram illustrating a configuration example of the projection apparatus. The projection device 1-2 includes a color synthesis unit 10-2, a polarization conversion unit 20, and a projection lens 30.

  The color synthesis unit 10-2 includes a color synthesis prism 11, a half-wave plate 12, and a quarter-wave plate 13. The polarization conversion unit 20 applies any one of the wavelength selective half-wave plate 21a, the uniaxial organic material 21b, and the uniaxial crystal 21c described above with reference to FIGS.

  The half-wave plate 12 is disposed on the green light incident side of the color combining prism 11 of the SPS system, and converts green S-polarized light g2s to P-polarized light to generate green P-polarized light g2p. The color combining prism 11 combines the red S-polarized light r2s that is the S-polarized light of the red light, the green P-polarized light g2p, and the blue S-polarized light b2s that is the S-polarized light of the blue light to generate combined light.

  The quarter-wave plate 13 is disposed on the output side of the color synthesis prism 11 so that the optical axis is in the direction of 45 ° with respect to the incident polarized light. Then, the red S-polarized light r2s is converted into red counterclockwise circularly polarized light r21 which is counterclockwise circularly polarized light, the green P-polarized light g2p is converted into green clockwise circularly polarized light g21 which is clockwise circularly polarized light, and the blue S-polarized light b2s is converted to left. It converts into blue counterclockwise circularly polarized light b21 which is circularly polarized light.

  The general basic function of the quarter-wave plate is that when light is transmitted, an optical path difference of 1/4 wavelength (phase difference δ = 90 ° + N ×) between two linearly polarized light (parallel component and vertical component). 360 °) and is often used mainly for the purpose of converting linearly polarized light into circularly polarized light and conversely converting circularly polarized light into linearly polarized light (N = 1, 2, 3,...).

  Here, when the outgoing light from the color synthesis prism 11 enters the projection lens 30, the reflected light reflected by the projection lens 30 may return to the color synthesis prism 11 again. When this happens, stray light is generated and a ghost phenomenon occurs on the screen.

  For this reason, in the above description, the quarter wavelength plate 13 is disposed between the emission stage of the color synthesizing prism 11 and the incident stage of the polarization conversion unit 20, and the quarter wavelength plate is used for stray light prevention. It is used as

  On the other hand, the polarization converter 20 biases the respective polarization states of the red counterclockwise circularly polarized light r21, the green clockwise circularly polarized light g21, and the blue counterclockwise circularly polarized light b21 emitted from the quarter wavelength plate 13 in all directions. It is converted into a uniform non-polarized state with no light.

  The projection lens 30 receives the combined light emitted from the polarization conversion unit 20 in which each color light is in a non-polarized state, and magnifies and projects the combined light. Thereafter, the projection light in a uniform non-polarized state with no bias in all directions is projected onto the screen.

  When the wavelength selective half-wave plate 21 a is used as the polarization conversion unit 20, the first optical axis is 45 ° with respect to the incident polarized light and the second light on the emission side of the color synthesis prism 11. The optical axis is oriented in the direction of 135 °. Alternatively, the first optical axis is 135 ° and the second optical axis is 45 ° with respect to the incident polarized light.

  When the uniaxial organic material 21b or the uniaxial crystal 21c is used as the polarization conversion unit 20, the slow axis is 45 ° or 135 ° with respect to the incident polarized light on the emission side of the color synthesis prism 11. Arrange so that the optical axis faces.

  With the configuration of the projector 1-2 as described above, the polarization state of the incident light on the screen and the polarization state of the reflected light on the screen are in a uniform non-polarized state with no bias in all directions. As a result, the color unevenness of the 3D image when the 3D glasses are not tilted completely disappears, and the color unevenness and the luminance drop of the 3D images when the 3D glasses are tilted can be completely eliminated. Can be greatly improved.

  FIG. 14 is a diagram illustrating a configuration example of the projection apparatus. The projection device 1-3 includes a color synthesis unit 10-3, a polarization conversion unit 20, and a projection lens 30. The polarization conversion unit 20 applies any one of the wavelength selective half-wave plate 21a, the uniaxial organic material 21b, and the uniaxial crystal 21c described above with reference to FIGS.

  The SSS color combining prism 11 combines red S-polarized light r3s which is S-polarized light of red light, green S-polarized light g3s which is S-polarized light of green light, and blue S-polarized light b3s which is S-polarized light of blue light. To generate synthetic light.

  The polarization conversion unit 20 converts the respective polarization states of the red S-polarized light r3s, the green S-polarized light g3s, and the blue S-polarized light b3s emitted from the color combining prism 11 into a uniform non-polarized state with no bias in all directions. .

  The projection lens 30 receives the combined light emitted from the polarization conversion unit 20 in which each color light is in a non-polarized state, and magnifies and projects the combined light. Thereafter, the projection light in a uniform non-polarized state with no bias in all directions is projected onto the screen.

  When the wavelength selective half-wave plate 21 a is used as the polarization conversion unit 20, the first optical axis is 45 ° with respect to the incident polarized light and the second light on the emission side of the color synthesis prism 11. The optical axis is oriented in the direction of 135 °. Alternatively, the first optical axis is 135 ° and the second optical axis is 45 ° with respect to the incident polarized light.

  When the uniaxial organic material 21b or the uniaxial crystal 21c is used as the polarization conversion unit 20, the slow axis is 45 ° or 135 ° with respect to the incident polarized light on the emission side of the color synthesis prism 11. Arrange so that the optical axis faces.

  With the configuration of the projection device 1-3 as described above, the polarization state of the incident light on the screen and the polarization state of the reflected light on the screen are in a uniform non-polarized state with no bias in all directions. As a result, the color unevenness of the 3D image when the 3D glasses are not tilted completely disappears, and the color unevenness and the luminance drop of the 3D images when the 3D glasses are tilted can be completely eliminated. Can be greatly improved.

  FIG. 15 is a diagram illustrating a configuration example of the projection apparatus. The projection device 1-4 includes a color synthesis unit 10-4, a polarization conversion unit 20, and a projection lens 30.

  The color synthesis unit 10-4 includes a color synthesis prism 11 and a quarter wavelength plate 13. The polarization conversion unit 20 applies any one of the wavelength selective half-wave plate 21a, the uniaxial organic material 21b, and the uniaxial crystal 21c described above with reference to FIGS.

  The SSS color combining prism 11 combines red S-polarized light r4s which is S-polarized light of red light, green S-polarized light g4s which is S-polarized light of green light, and blue S-polarized light b4s which is S-polarized light of blue light. To generate synthetic light.

  The quarter-wave plate 13 is disposed on the emission side of the color synthesis prism 11 so that the optical axis is oriented in the direction of 45 ° with respect to the incident polarized light in order to prevent the stray light described above. Then, the quarter wavelength plate 13 converts the red S-polarized light r4s into red counterclockwise circularly polarized light r41 which is counterclockwise circularly polarized light, and converts the green S-polarized light g4s into green counterclockwise circularly polarized light g41 which is counterclockwise circularly polarized light. Then, the blue S-polarized light b4s is converted into blue counterclockwise circularly polarized light b41 which is counterclockwise circularly polarized light.

  The polarization converter 20 has no polarization in all directions with respect to the respective polarization states of the red counterclockwise circularly polarized light r41, the green counterclockwise circularly polarized light g41, and the blue counterclockwise circularly polarized light b41 emitted from the quarter wavelength plate 13. Convert to a uniform unpolarized state.

  The projection lens 30 receives the combined light emitted from the polarization conversion unit 20 in which each color light is in a non-polarized state, and magnifies and projects the combined light. Thereafter, the projection light in a uniform non-polarized state with no bias in all directions is projected onto the screen.

  When the wavelength selective half-wave plate 21 a is used as the polarization conversion unit 20, the first optical axis is 45 ° with respect to the incident polarized light and the second light on the emission side of the color synthesis prism 11. The optical axis is oriented in the direction of 135 °. Alternatively, the first optical axis is 135 ° and the second optical axis is 45 ° with respect to the incident polarized light.

  When the uniaxial organic material 21b or the uniaxial crystal 21c is used as the polarization conversion unit 20, the slow axis is 45 ° or 135 ° with respect to the incident polarized light on the emission side of the color synthesis prism 11. Arrange so that the optical axis faces.

  With the configuration of the projection device 1-4 as described above, the polarization state of the incident light on the screen and the polarization state of the reflected light on the screen are in a uniform non-polarized state with no bias in all directions. As a result, the color unevenness of the 3D image when the 3D glasses are not tilted completely disappears, and the color unevenness and the luminance drop of the 3D images when the 3D glasses are tilted can be completely eliminated. Can be greatly improved.

  FIG. 16 is a diagram illustrating a configuration example of the projection apparatus. The projection device 1-5 includes a color synthesis unit 10-5, a uniaxial crystal 21c, and a projection lens 30.

  The color synthesis unit 10-5 includes a color synthesis prism 11 and a half-wave plate 12. In the example of FIG. 16, the uniaxial crystal 21c (quartz crystal) described above with reference to FIGS. 9 to 11 is applied as the polarization converter.

  The half-wave plate 12 is disposed on the green light incident side of the color combining prism 11 of the SPS method, and converts the S-polarized light g5s of the green light into P-polarized light to generate the green P-polarized light g5p. The color combining prism 11 combines the red S-polarized light r5s that is the S-polarized light of the red light, the green P-polarized light g5p, and the blue S-polarized light b5s that is the S-polarized light of the blue light to generate combined light.

  The uniaxial crystal 21c converts the respective polarization states of the red S-polarized light r5s, the green P-polarized light g5p, and the blue S-polarized light b5s emitted from the color synthesizing prism 11 into a uniform non-polarized state with no bias in all directions.

  The projection lens 30 receives the combined light, which is emitted from the uniaxial crystal 21c and in which each color light is in the non-polarized state, and projects the enlarged light at a predetermined magnification. Thereafter, the projection light in a uniform non-polarized state with no bias in all directions is projected onto the screen.

  In addition, the uniaxial crystal 21c is arranged on the emission side of the color synthesis prism 11 so that the slow axis is 45 ° or 135 ° with respect to the incident polarized light.

  With the configuration of the projection device 1-5 as described above, the polarization state of the incident light on the screen and the polarization state of the reflected light on the screen are in a uniform non-polarized state with no bias in all directions. As a result, the color unevenness of the 3D image when the 3D glasses are not tilted completely disappears, and the color unevenness and the luminance drop of the 3D images when the 3D glasses are tilted can be completely eliminated. Can be greatly improved.

  In the projectors 1-1 to 1-5, a plastic lens can be used for the projection lens 30 (a plastic lens having a large polarization unevenness can also be used). Further, in the optical form such as the projection device 1-5, the color synthesizing prism 11 is used in the SPS method, so that the 2D luminance is maximized. In addition, the projection apparatus 1-5 shown in FIG. 16 becomes the best optical form.

  Next, an installation form of the polarization conversion unit 20 in the projection apparatus 1 will be described. FIG. 17 is a diagram showing an installation mode example. The projection device 1a-1 includes a color synthesis prism 11 (SPS system), a half-wave plate 12, a polarization conversion unit 20, and a projection lens 30.

  A half-wave plate 12 is installed on the green light incident side of the color combining prism 11. In addition, a projection lens 30 is installed on the light output side of the combined light of the color combining prism 11. Further, a polarization conversion unit 20 is installed between the incident side of the projection lens 30 and the emission side of the color synthesis prism 11. In this case, the polarization conversion unit 20 is bonded to the emission surface of the color synthesis prism 11 and integrated with the color synthesis prism 11. Note that the half-wave plate 12 may not be provided as an installation form. Further, the color synthesis prism 11 may be any type of color synthesis prism such as SPS or SSS.

  FIG. 18 is a diagram showing an installation mode example. The projection device 1a-2 includes a color synthesis prism 11 (SPS method), a half-wave plate 12, a polarization conversion unit 20, and a projection lens 30.

  A half-wave plate 12 is installed on the green light incident side of the color combining prism 11. In addition, a projection lens 30 is installed on the light output side of the combined light of the color combining prism 11. Further, a mechanical frame component 4 a that is an attachment mechanism unit for installing the polarization conversion unit 20 is provided between the incident side of the projection lens 30 and the emission side of the color synthesis prism 11.

  The polarization conversion unit 20 can be inserted into and removed from the mechanical frame component 4a, and is inserted into the mechanical frame component 4a, so that the polarization conversion unit 20 is inserted between the emission side of the color synthesis prism 11 and the incident side of the projection lens 30. Fixedly installed. Note that the half-wave plate 12 may not be provided as an installation form. Further, the color synthesis prism 11 may be any type of color synthesis prism such as SPS or SSS.

  FIG. 19 is a diagram showing an installation mode example. The projection device 1a-3 includes a color synthesis prism 11 (SPS method), a half-wave plate 12, a polarization conversion unit 20, and a projection lens 30.

  A half-wave plate 12 is installed on the green light incident side of the color combining prism 11. In addition, a projection lens 30 is installed on the light output side of the combined light of the color combining prism 11. Further, a mechanical frame part 4 b that is an attachment mechanism unit for installing the polarization conversion unit 20 is provided on the incident surface of the projection lens 30.

  The projection lens 30 has, for example, a lens shift mechanism that shifts the lens vertically and horizontally, and the mechanical frame component 4b follows the lens shift of the projection lens 30. The polarization conversion unit 20 can be inserted into and removed from such a mechanical frame part 4b, and the polarization conversion unit 20 is inserted into the mechanical frame part 4b, so that it always follows the lens shift of the projection lens 30. However, it is installed close to the incident surface side of the projection lens 30. Note that the half-wave plate 12 may not be provided as an installation form. Further, the color synthesis prism 11 may be any type of color synthesis prism such as SPS or SSS.

  Here, the light source used in the projection apparatus 1 will be described. The projection apparatus 1 uses a light source having a continuous emission spectrum with a wide range of wavelengths or a light source having a continuous spectrum with a wide range of wavelengths in RGB projection light.

  Therefore, since a general LCD projector uses a continuous wavelength light source such as a UHP (Ultra High Performance) lamp or an Xe (xenon) lamp, the function of the projection device 1 can be applied to virtually all LCD projectors. Can be applied.

  Next, the difference between the prior art and the present technology will be described. FIG. 20 is a diagram showing a projection image of the projection apparatus. In the projection light emitted from the conventional projector 300, the incident light to the screen 7 and the reflected light from the screen 7 are not depolarized. On the other hand, the projection light emitted from the projection apparatus 1 according to the present technology is made non-polarized in all directions uniformly with respect to the incident light on the screen 7 and the reflected light from the screen 7.

  As described above, according to the projection device 1, the polarization conversion unit 20 is disposed between the emission side of the synthesized light of the color synthesis prism 11 and the incident side of the projection lens 30. In this way, by arranging the polarization conversion unit 20 closer to the color synthesis prism 11 (on the exit side) than on the projection side of the projection lens 30, all RGB projection light is uniform in all directions. Can be made non-polarized.

  Thereby, it is possible to completely eliminate the color unevenness of the 3D image through the 3D glasses without tilting the 3D glasses. Furthermore, for example, when the 3D glasses are tilted by about ± 25 ° (assuming the use range of the customer), it is possible to completely eliminate the color unevenness / luminance drop of the 3D images through the 3D glasses.

  Furthermore, since the projection apparatus 1 can cope with any active shutter 3D LCD projector, optical member, or usage environment, it has high affinity and excellent serviceability. For example, it can be applied to LCD projectors such as all reflective LCDs and transmissive LCDs, and can be compatible with any color combining prism (SPS system, SSS system).

  Moreover, it is also possible to use a plastic lens for the projection lens or the like, and it is possible to deal with any screen (silver screen, bead screen, mat screen, etc.).

  As for the cost when the uniaxial crystal 21c is used for the polarization conversion unit 20, the wavelength selective half-wave plate 21a installed on the incident side of the projection lens 30 (it is expensive and increases the area). In some cases, the uniaxial crystal 21c (which is cheaper itself and is more inexpensive when the area of the color synthesis prism is small) is much cheaper and can exhibit a high effect. The cost of the uniaxial crystal 21c (quartz crystal) is about 1/4 to 1/5 that of the wavelength selective half-wave plate 21a and the uniaxial organic material 21b.

In addition, this technique can also take the following structures.
(1) a color synthesis unit that synthesizes the three primary color lights and emits the synthesized light;
A polarization conversion unit that is disposed on the emission side of the color combining unit and converts the polarization state of each color light of the combined light into a non-polarized state uniformly in all directions;
A projection lens for projecting light emitted from the polarization converter;
A projection apparatus.
(2) The polarization converter includes a wavelength-selective half-wave plate that shifts the phase by π with respect to a predetermined wavelength, a uniaxial organic material that is an organic material having one optical axis, and a crystal that has one optical axis. The projection device according to (1), wherein the projection device is any one of the uniaxial crystals.
(3) The color synthesis unit includes a color synthesis prism and a half-wave plate arranged on the green light incident side of the color synthesis prism,
The polarization converter is the uniaxial crystal;
The half-wave plate converts green S-polarized light to P-polarized light,
The color combining prism combines red S-polarized light that is S-polarized light of red light, green P-polarized light that is P-polarized light of green light, and blue S-polarized light that is S-polarized light of blue light,
The uniaxial crystal is the projection device according to (1) or (2), wherein the red S-polarized light, the green P-polarized light, and the blue S-polarized light are converted into a non-polarized state.
(4) The color synthesis unit includes a color synthesis prism and a half-wave plate arranged on the green light incident side of the color synthesis prism,
The half-wave plate converts green S-polarized light to P-polarized light,
The color combining prism combines red S-polarized light that is S-polarized light of red light, green P-polarized light that is P-polarized light of green light, and blue S-polarized light that is S-polarized light of blue light,
The projection device according to (1) or (2), wherein the polarization conversion unit converts the red S-polarized light, the green P-polarized light, and the blue S-polarized light into a non-polarized state.
(5) The color synthesizing unit includes a color synthesizing prism, a half-wave plate disposed on the green light incident side of the color synthesizing prism, an incident side of the polarization converting unit, and an emission side of the color synthesizing prism. A quarter-wave plate disposed between and
The half-wave plate converts green S-polarized light to P-polarized light,
The color combining prism combines red S-polarized light that is S-polarized light of red light, green P-polarized light that is P-polarized light of green light, and blue S-polarized light that is S-polarized light of blue light,
The quarter-wave plate converts the red S-polarized light into red counter-clockwise circularly polarized light that is counterclockwise circularly polarized light, converts the green P-polarized light into green-clockwise circularly polarized light that is clockwise circularly polarized light, and Convert S-polarized light to blue-handed circularly polarized light, which is counterclockwise circularly polarized light,
The projection apparatus according to (1) or (2), wherein the polarization converter converts each polarization state of the red counterclockwise circularly polarized light, the green clockwise circularly polarized light, and the blue counterclockwise circularly polarized light into a non-polarized state. .
(6) The color synthesis unit includes a color synthesis prism,
The color combining prism combines red S-polarized light that is S-polarized light of red light, green S-polarized light that is S-polarized light of green light, and blue S-polarized light that is S-polarized light of blue light,
The projection device according to (1) or (2), wherein the polarization conversion unit converts the red S-polarized light, the green S-polarized light, and the blue S-polarized light into a non-polarized state.
(7) The color synthesizing unit includes a color synthesizing prism, and a quarter-wave plate disposed between the incident side of the polarization conversion unit and the emission side of the color synthesizing prism,
The color combining prism combines red S-polarized light that is S-polarized light of red light, green S-polarized light that is S-polarized light of green light, and blue S-polarized light that is S-polarized light of blue light,
The quarter-wave plate converts the red S-polarized light into red counterclockwise circularly polarized light that is counterclockwise circularly polarized light, converts the green S-polarized light into green counterclockwise circularly polarized light that is counterclockwise circularly polarized light, and the blue color Convert S-polarized light to blue-handed circularly polarized light, which is counterclockwise circularly polarized light,
The projection device according to (1) or (2), wherein the polarization conversion unit converts each polarization state of the red counterclockwise circularly polarized light, the green counterclockwise circularly polarized light, and the blue counterclockwise circularly polarized light into a non-polarized state. .
(8) The polarization conversion unit is bonded to an emission surface of a color synthesis prism included in the color synthesis unit, and is integrated with the color synthesis prism according to any one of (1) to (7). Projection device.
(9) The polarization conversion unit is fixedly installed through an attachment mechanism unit placed between the emission side of the color synthesis prism included in the color synthesis unit and the incident side of the projection lens. The projection device according to any one of (7).
(10) The projection device according to any one of (1) to (7), wherein the polarization conversion unit is disposed close to an incident surface side of the projection lens and follows a lens shift of the projection lens. .

  Note that various modifications can be made to the above-described embodiment without departing from the gist of the embodiment.

  Further, the above-described embodiments can be modified and changed by those skilled in the art, and are not limited to the exact configurations and application examples described.

  DESCRIPTION OF SYMBOLS 1 ... Projection apparatus, 2 ... 3D glasses, 7 ... Screen, 10 ... Color composition part, 20 ... Polarization conversion part, 30 ... Projection lens

In order to solve the above problems, a projection apparatus is provided. The projection device includes a color synthesis unit, a polarization conversion unit, and a projection lens. The color combining unit includes a color combining prism and a half-wave plate disposed on the green light incident side of the color combining prism, and combines the three primary color lights to emit combined light. The polarization conversion unit is disposed on the emission side of the color synthesis unit, and converts the polarization state of each color light of the combined light uniformly into a non-polarization state with respect to all directions. The projection lens projects the outgoing light from the polarization conversion unit. In addition, the polarization conversion unit is integrated with the color synthesis prism .

Claims (4)

A color combining prism that includes a color combining prism and a half-wave plate disposed on the green light incident side of the color combining prism;
A polarization conversion unit that is disposed on the emission side of the color combining unit and converts the polarization state of each color light of the combined light into a non-polarized state uniformly in all directions;
A projection lens for projecting light emitted from the polarization converter;
With
The said polarization conversion part is a projection apparatus which installs close to the entrance plane side of the said projection lens, and follows the lens shift of the said projection lens.   The polarization converter includes a wavelength selective half-wave plate that shifts the phase by π with respect to a predetermined wavelength, a uniaxial organic material that is an organic material having one optical axis, and a uniaxial crystal that has one optical axis. The projection device according to claim 1, wherein the projection device is any one of a crystalline crystal. The polarization converter is the uniaxial crystal;
The half-wave plate converts green S-polarized light to P-polarized light,
The color combining prism combines red S-polarized light that is S-polarized light of red light, green P-polarized light that is P-polarized light of green light, and blue S-polarized light that is S-polarized light of blue light,
The projection apparatus according to claim 2, wherein the uniaxial crystal converts the red S-polarized light, the green P-polarized light, and the blue S-polarized light into a non-polarized state.   It further includes an attachment mechanism portion that allows the polarization conversion portion to be inserted and removed, and a lens shift mechanism that shifts the lens up and down, left and right, and the attachment mechanism portion follows the lens shift by the lens shift mechanism, so that the attachment 4. The projection device according to claim 1, wherein the polarization conversion unit attached to the mechanism unit is installed close to the incident surface side while following the lens shift. 5.

Images