JP2010020194A - Optical system and multi-plate type projection device with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical system which separates colors with a dichroic film and a multi-plate type projection device with the same, the optical system and the multi-plate type projection device causing little loss of light quantity and having excellent color reproducibility. <P>SOLUTION: On a color separating and synthesizing section 20 including the dichroic film to separate colors and a polarizing film to synthesize colors, a wavelength component to be a projection light beam 5 is made incident in a polarization direction in which the dichroic film 23 exhibits excellent characteristics. Thereby suppression of loss of light quantity and high color reproducibility are achieved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical system for color separation by a dichroic film and a multi-plate projection apparatus including the same.

Nowadays, a multi-plate projection apparatus including a plurality of reflective spatial light modulators using a reflective liquid crystal (LCOS) or a micromirror device has been developed and commercialized.
In general, in a multi-plate projection apparatus, in addition to an optical system (hereinafter referred to as an illumination projection separation optical system) for separating the direction of illumination light and projection light used also in a single-plate projection apparatus, each spatial light An optical system that performs color separation and synthesis for modulating a predetermined color component by the modulator (hereinafter referred to as a color separation / synthesis optical system) is required.

Patent Document 1, Patent Document 2, Patent Document 3, and Non-Patent Document 1 disclose a multi-plate projection apparatus having an illumination projection separation optical system and a color separation / synthesis optical system.
FIG. 28 is a configuration diagram of a three-plate projector using a reflective liquid crystal (LCOS) as a spatial light modulator, and is disclosed in Patent Document 1. A PBS prism having a polarizing film is used as the illumination projection separation optical system, and a dichroic prism composed of a Kester type prism or the like is used as the color separation / synthesis optical system.

  FIG. 29 is a configuration diagram of a two-plate projection apparatus using a micromirror device as a spatial light modulator, and is disclosed in Non-Patent Document 1. A TIR (Total Internal Reflection) prism is used as the illumination projection separation optical system, and a dichroic prism is used as the color separation / synthesis optical system.

  30A and 30B are configuration diagrams of a three-plate projection device using a micromirror device as a spatial light modulator, and are disclosed in Patent Document 2. FIG. A TIR prism is used as the illumination projection separation optical system, and a cross dichroic prism is used as the color separation / synthesis optical system.

FIG. 31 is a configuration diagram of a three-plate projection apparatus using a micromirror device as a spatial light modulator, and is disclosed in Patent Document 3. A TIR prism is used as the illumination projection separation optical system, and a Philips type dichroic prism is used as the color separation / synthesis optical system.
JP 2000-171923 A JP 2007-025287 A US Pat. No. 4,969,730 Optical Technology Information Magazine “Light Edge”, No.19, P.63, [online], July 2000, USHIO INC., [March 26, 2008 search], Internet <URL: http: // www.ushio.co.jp/documents/technology/lightedge/lightedge_19/ushio_le19-03.pdf>

  Incidentally, it is known that the characteristics of the dichroic film included in the dichroic prism and the polarizing film included in the PBS prism change depending on the incident angle. When a micromirror device is used as a spatial light modulator, the optical path of illumination light incident on the micromirror device and the optical path of reflected projection light are usually different.

  When the dichroic film or the polarizing film acts on both illumination light and projection light as in the above-mentioned patent document, the incident angle varies due to the difference in the optical path, and it is difficult to optimize the characteristics. This causes deterioration of the transmission / reflectance characteristics with respect to the wavelength range of the dichroic film and the polarization state of the polarizing film. As a result, the accuracy of separation and synthesis deteriorates, resulting in problems such as loss of light quantity and color reproducibility. It becomes a factor.

  For example, as shown in FIG. 32, the reflectance characteristics exhibited by the dichroic film differ depending on the incident angles of the illumination light 91 and the projection light 92, and as a result, the wavelength component 90 that is reflected by the illumination light but not reflected by the projection light. There is a possibility that light quantity loss will occur.

A similar problem occurs when a reflective liquid crystal (LCOS) is used as a spatial light modulator that is illuminated from an oblique direction.
In addition, since the dichroic film is an optical element that causes different actions depending on the wavelength component of the light beam, the polarization state is not necessarily considered unlike the polarizing film. However, the characteristics of dichroic films change depending on the polarization state, and some of the dichroic films have excellent characteristics with P-polarized light and some have excellent characteristics with S-polarized light.

  For example, in FIGS. 33A and 33B illustrating the characteristics of a dichroic film that transmits a wavelength component corresponding to red (hereinafter referred to as a red (R) component) (hereinafter referred to as an R transmission type), the characteristics of P-polarized light are illustrated in FIGS. In FIG. 33B, which shows the characteristics of S-polarized light, compared to FIG. 33A, the lines indicating the transmittance characteristics for each incident angle are steeper and close to each other. That is, when the incident light is S-polarized light, the deterioration of characteristics depending on the incident angle is small, and high color reproducibility can be obtained. On the other hand, in FIG. 34A and FIG. 34B illustrating the characteristics of the dichroic film that reflects the red (R) component (hereinafter referred to as “R reflection type”), FIG. 34A that shows the characteristics of P-polarized light is superior.

  In light of the above circumstances, an object of the present invention is to provide an optical system with little light loss and good color reproducibility, and a multi-plate projection apparatus including the same.

  According to a first aspect of the present invention, a plurality of reflective spatial light modulators and color separation depending on an incident angle with respect to a specific polarization direction in which illumination light from the outside is color-separated and guided to the reflective spatial light modulator. A first dichroic film with little deterioration in characteristics and a color separation / synthesis unit including a color synthesizing unit that synthesizes the modulated light by the reflective spatial light modulator, and the polarized light specific to the first dichroic film in the illumination light An optical system that projects only a wavelength component incident in a direction is provided.

  According to a second aspect of the present invention, in the optical system according to the first aspect, the plurality of reflective spatial light modulators are two reflective spatial light modulators, and the color synthesizing means is a polarizing film. The color separation / combination unit is composed of two prisms in which a first dichroic film and a polarizing film are disposed on the joint surface, and further, between one of the two reflective spatial light modulators and the color separation / combination unit. An optical system including a wave plate is provided. Thereby, in any one of the reflection type spatial light modulators, different polarization directions can be realized for incident light and reflected light.

  According to a third aspect of the present invention, in the optical system according to the second aspect, the wavelength plate acts as a 1 / 4λ plate only for a wavelength component incident on the 1 / 4λ plate or the reflective spatial light modulator. Provided is an optical system that is a wavelength polarization conversion element and is disposed across both an incident optical path and a reflected optical path of a reflective spatial light modulator.

  According to a fourth aspect of the present invention, in the optical system according to the second aspect, the wavelength plate acts as a ½λ plate only for the wavelength component incident on the ½λ plate or the reflective spatial light modulator. Provided is an optical system which is a wavelength polarization conversion element and is disposed so as to intersect only one of an incident optical path and a reflected optical path of a reflective spatial light modulator.

  According to a fifth aspect of the present invention, in the optical system according to any one of the second to fourth aspects, a specific wavelength polarization conversion is further performed on the optical path of the synthesized light emitted from the color separation / synthesis unit. An optical system including an element is provided. Thereby, the deflection | deviation direction of synthetic | combination light can be unified to a fixed direction.

  According to a sixth aspect of the present invention, in the optical system according to any one of the second to fifth aspects, the projection is further arranged on the optical path of the synthesized light emitted from the color separation / synthesis unit. Each of the two reflective spatial light modulators and one field lens disposed between the color separation / combination unit. The projection lens and the field lens are substantially arranged on the reflective spatial light modulator side. An optical system acting as a telecentric optical system is provided. Thereby, since the entrance pupil position of the projection lens can be brought closer to the spatial light modulator side, the beam diameter in the projection optical system can be reduced.

  A seventh aspect of the present invention provides the optical system according to the sixth aspect, wherein the entrance pupil position of the projection lens is in the vicinity of the polarizing film. According to this configuration, since the light beam diameter in the color separation / synthesis unit can be particularly reduced, it is effective to reduce the size of the color separation / synthesis unit.

  An eighth aspect of the present invention provides the optical system according to the sixth aspect, wherein the entrance pupil position of the projection lens is closer to the projection lens than the color separation / synthesis unit. According to this configuration, the diameter of the light beam in the projection lens can be particularly reduced, which is effective for reducing the effective diameter of the projection lens.

According to a ninth aspect of the present invention, there is provided the optical system according to any one of the second to eighth aspects, wherein the two prisms have different shapes.
According to a tenth aspect of the present invention, in the optical system according to any one of the second to eighth aspects, the two prisms are triangular prisms having the same shape, and the color separation / synthesis unit includes four An optical system having a prismatic shape is provided. As a result, since only one type of prism is used and a simple triangular prism shape is obtained, an effect of cost reduction can be obtained. Moreover, it becomes possible to arrange | position two reflection type spatial light modulators on the same plane, and can reduce the burden required for packaging.

  According to an eleventh aspect of the present invention, in the optical system according to any one of the second to eighth aspects, the two prisms are triangular prisms having the same shape, and the color separation / synthesis unit is a triangular prism. An optical system having a shape is provided. As a result, since only one type of prism is used and a simple triangular prism shape is obtained, an effect of cost reduction can be obtained.

  According to a twelfth aspect of the present invention, in the optical system according to any one of the second to eleventh aspects, the reflective spatial light modulator is incident by controlling the inclination of the plurality of micromirrors. This is a micromirror device that modulates light. The micromirror device is designed to make incident light incident from an oblique direction relative to the normal to the normal of the reflective surface of the micromirror before the micromirror is controlled. An optical system that reflects in an oblique direction is provided. According to this configuration, incident light and reflected light can be easily separated.

  According to a thirteenth aspect of the present invention, in the optical system according to any one of the second to eleventh aspects, the reflective spatial light modulator is incident by controlling the inclination of the plurality of micromirrors. This is a micromirror device that modulates light, and the micromirror device is designed to make incident light incident in an oblique direction relative to the normal of the reflective surface of the micromirror before the micromirror is controlled. A reflecting optical system is provided.

  According to a fourteenth aspect of the present invention, in the optical system according to any one of the second to eleventh aspects, the reflective spatial light modulator is a reflective liquid crystal (LCOS), and the reflective liquid crystal Provides an optical system that reflects incident light incident in an oblique direction with respect to the normal line of the reflective surface of the reflective liquid crystal in an oblique direction with respect to the normal line. According to this configuration, incident light and reflected light can be easily separated.

  According to a fifteenth aspect of the present invention, in the optical system according to any one of the second to fourteenth aspects, the specific polarization direction is P-polarized light, and the first dichroic film is red. Provided is an optical system that reflects corresponding wavelength components and transmits wavelength components corresponding to green and blue.

  According to a sixteenth aspect of the present invention, in the optical system according to any one of the second to fourteenth aspects, the specific polarization direction is S-polarized light, and the first dichroic film is red. Provided is an optical system that transmits corresponding wavelength components and reflects wavelength components corresponding to green and blue.

  According to a seventeenth aspect of the present invention, in the optical system according to the first aspect, the plurality of reflective spatial light modulators are two reflective spatial light modulators, and the color synthesizing means has a specific polarization direction. On the other hand, the second dichroic film has little deterioration in color separation characteristics depending on the incident angle, and the color separation / synthesis unit includes two prisms in which the first dichroic film and the second dichroic film are arranged on the joint surface. An optical system including a polarizing plate configured and further disposed on the optical path of the combined light emitted from the color separation / synthesis unit is provided.

  According to an eighteenth aspect of the present invention, in the optical system according to the seventeenth aspect, the specific polarization direction is P-polarized light, the polarizing plate transmits only P-polarized light, the first dichroic film, and the second This dichroic film provides an optical system that reflects a wavelength component corresponding to red and transmits wavelength components corresponding to green and blue.

  According to a nineteenth aspect of the present invention, in the optical system according to the seventeenth aspect, the specific polarization direction is S-polarized light, the polarizing plate transmits only S-polarized light, and the first dichroic film and the second dichroic film This dichroic film provides an optical system that transmits a wavelength component corresponding to red and reflects wavelength components corresponding to green and blue.

  According to a twentieth aspect of the present invention, a TIR prism that directs illumination light, a plurality of micromirror devices that modulate different wavelength components of the illumination light, and the illumination light depends on an incident angle with respect to a specific polarization direction. A dichroic prism that separates by a dichroic film with little deterioration in color separation characteristics and leads to a micromirror device, and synthesizes the modulated light from the micromirror device with the dichroic film, and polarization that transmits only P-polarized light among the combined light synthesized by the dichroic prism And an optical system for projecting only a component of illumination light incident on a dichroic film in a specific polarization direction.

  A twenty-first aspect of the present invention provides the optical system according to the twentieth aspect, wherein the specific polarization direction is P-polarized light. As a result, P-polarized light having good characteristics of the TIR prism can be incident on the TIR prism.

  According to a twenty-second aspect of the present invention, in the optical system according to the twentieth aspect, the specific polarization direction is S-polarized light, and the optical system further includes a ½λ plate between the TIR prism and the dichroic prism. provide. As a result, even when the polarization direction in which the TIR prism exhibits good characteristics and the polarization direction in which the dichroic film exhibits good characteristics are different, polarized light having good characteristics can be incident on each.

  A twenty-third aspect of the present invention provides the optical system according to the twenty-first aspect, wherein the dichroic film reflects a wavelength component corresponding to red and transmits a wavelength component corresponding to green and blue. .

  A twenty-fourth aspect of the present invention provides the optical system according to the twenty-second aspect, wherein the dichroic film transmits a wavelength component corresponding to red and reflects a wavelength component corresponding to green and blue. .

  According to a twenty-fifth aspect of the present invention, there is provided a light source that emits illumination light including a plurality of wavelength components, and a wavelength selective polarization that selectively converts the polarization direction of the illumination light while switching the wavelength component that converts the polarization direction over time. A projection apparatus that includes a conversion unit and the optical system according to the first aspect or the twentieth aspect, and projects a wavelength component of the illumination light whose polarization direction has not been converted by the wavelength selective polarization conversion unit. To do.

  According to a twenty-sixth aspect of the present invention, in the projection apparatus according to the twenty-fifth aspect, the plurality of wavelength components are wavelength components corresponding to red, green, and blue, and the wavelength selective polarization converter is a green color of the illumination light. A projection device is provided that alternately converts the polarization direction of the wavelength component corresponding to 1 and the polarization direction of the wavelength component corresponding to blue.

  According to a twenty-seventh aspect of the present invention, in the projection apparatus according to the twenty-fifth aspect, the wavelength selective polarization conversion unit selectively changes the polarization direction of the illumination light while switching the wavelength component for converting the polarization direction over time. A projection device for converting P-polarized light to S-polarized light is provided.

  According to a twenty-eighth aspect of the present invention, in the projection apparatus according to the twenty-fifth aspect, the plurality of wavelength components are wavelength components corresponding to red, green, and blue, and the wavelength selective polarization converter is a green color of the illumination light. A projection device is provided that alternately converts the polarization direction of the wavelength component corresponding to 1 and the polarization direction of the wavelength component corresponding to blue to P polarization to S polarization.

  According to a twenty-ninth aspect of the present invention, in the projection device according to the twenty-sixth aspect or the twenty-eighth aspect, the time for projecting the wavelength component corresponding to green is equal to or longer than the time for projecting the wavelength component corresponding to blue. A projection device is provided. As a result, the projected image shows good white balance.

  According to a thirtieth aspect of the present invention, in the projection device according to the twenty-ninth aspect, the ratio of the time for projecting the wavelength component corresponding to green to the time for projecting the wavelength component corresponding to blue is 0.7: 0. .3 to 0.5: 0.5 is provided.

  According to a thirty-first aspect of the present invention, in the projection device according to any one of the twenty-fifth to thirtieth aspects, the illumination light emitted from the light source is further specified between the light source and the wavelength selective polarization converter. A projection apparatus including a polarization conversion unit that converts the polarization direction into a polarization direction is provided.

  According to a thirty-second aspect of the present invention, in the projection apparatus according to any one of the twenty-fifth to thirty-first aspects, the wavelength selective polarization conversion units are arranged radially on the same plane, and are circular as a whole. A plurality of specific wavelength polarization conversion elements, wherein the plurality of specific wavelength polarization conversion elements provide a projection device that is rotated about an axis of rotation that is perpendicular to a plane and passes through a circular center.

  According to a thirty-third aspect of the present invention, in the projection device according to any one of the twenty-fifth to thirty-first aspects, the wavelength selective polarization conversion unit forms a cylinder as a whole and is disposed on the cylindrical surface. The projector includes a plurality of specific wavelength polarization conversion elements and reflecting means disposed inside the cylinder, and the plurality of specific wavelength polarization conversion elements provide a projection device that rotates about a rotation axis passing through the center of the cylinder. According to this configuration, since the characteristics of the specific wavelength polarization conversion element do not change due to rotation, it is possible to achieve efficient polarization direction conversion.

  A thirty-fourth aspect of the present invention is the projection apparatus according to any one of the twenty-fifth to thirty-first aspects, wherein the wavelength selection polarization conversion unit includes a plurality of specific wavelength polarization conversions arranged in a certain direction. A plurality of specific wavelength polarization conversion elements including an element provide a projection device that slides along a certain direction. According to this configuration, since the characteristics of the specific wavelength polarization conversion element do not change due to rotation, it is possible to achieve efficient polarization direction conversion.

  According to a thirty-fifth aspect of the present invention, in the projection device according to any one of the twenty-fifth to thirty-first aspects, the wavelength selective polarization conversion unit electrically controls the wavelength component for converting the polarization direction. Provided is a projection device which is an electronic color-specific polarization control means for switching.

  According to the present invention, the wavelength component used as the projection light is incident on the dichroic film in the polarization direction in which the dichroic film exhibits good characteristics, so that it is possible to suppress deterioration of characteristics depending on the incident angle. Accordingly, it is possible to provide an optical system with little light loss and good color reproducibility and a multi-plate projection apparatus including the same.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating the configuration of a two-plate projection device 100 according to this embodiment. The projection apparatus 100 includes a light source 11, a polarization conversion unit 12, a wheel-type wavelength selective polarization conversion unit 13, a ¼λ plate 14, a first spatial light modulator 15, a second spatial light modulator 16, and a color separation / synthesis unit. 20 includes a control circuit (not shown) for controlling the spatial light modulator and a projection lens (not shown). The color separation / combination unit 20 includes two prisms (prisms 21 and 22) having different shapes, and transmits an R-transmissive dichroic film 23 and P-polarized light on the joint surface of the prisms (hereinafter referred to as P-polarized and transmissive type). A polarizing film 24 is disposed. The dichroic film 23 is an S-polarized dichroic film that exhibits excellent characteristics with respect to S-polarized light. In the present embodiment, each of the first spatial light modulator 15 and the second spatial light modulator 16 uses a micromirror device. The mirror device includes a plurality of micromirrors, and modulates incident light by controlling the tilt of each micromirror.

  FIG. 2 is a diagram illustrating the configuration of the wheel-type wavelength selective polarization converter 13 included in the projection apparatus 100 according to this embodiment. The wheel-type wavelength selective polarization converter 13 divides the whole into four regions, and changes only the polarization direction of the wavelength component corresponding to blue (B) (hereinafter referred to as blue (B) component) from S-polarized light to P-polarized light. Wavelength components corresponding to green (G) (hereinafter referred to as green (G) and specific wavelength polarization conversion element 13a and specific wavelength polarization conversion element 13c (hereinafter referred to as blue (B) specific wavelength polarization conversion element) and wavelength (G) that are selectively converted. A specific wavelength polarization conversion element 13b and a specific wavelength polarization conversion element 13d (hereinafter referred to as a green (G) specific wavelength polarization conversion element) that selectively converts only the polarization direction of S) to P polarization. It is comprised by combining alternately. Each specific wavelength polarization conversion element is arranged so as to be perpendicular to the optical axis of the incident light. Each specific wavelength polarization conversion element has a polarization direction of incident light that is indicated by a bidirectional arrow in FIG. 2 when the incident light passes through each specific wavelength polarization conversion element. If they match, the polarization direction of light can be converted in a wavelength selective manner most efficiently. More specifically, there is little deviation between the wavelength component intended to convert the polarization direction and the selected wavelength component that the specific wavelength polarization conversion element actually converts the polarization direction, and the specific wavelength polarization conversion element has a high transmittance. It will be transparent.

In addition, as such a specific wavelength polarization conversion element, there is, for example, Color Select of Color Link.
Further, the wheel-type wavelength selective polarization conversion unit 13 is not limited to the configuration illustrated in FIG. 2, and at least two types of specific wavelength polarization conversion elements that selectively convert the polarization direction of a specific wavelength component. As long as it is configured. The modification will be described in detail later.

  Hereinafter, the flow until the illumination light 1 emitted from the light source 11 is projected as projection light 5 onto a screen (not shown) will be described together with the operation of each component of the projection device 100 with reference to FIG. .

  First, the illumination light 1 including a plurality of wavelength components and a plurality of polarization directions emitted from a light source 11 such as a mercury lamp enters the polarization conversion unit 12 via a reflector (not shown), a rod integrator, or the like. The illumination light 1 incident on the polarization conversion unit 12 is converted into illumination light 2 having only a specific polarization direction. Here, the polarization converter 12 acts to convert the illumination light 1 into S-polarized light. More specifically, for example, the polarization light 12 is converted into P-polarized light and S-polarized light using a polarization element that transmits only P-polarized light. By separating the light into P-polarized light and transmitting only the P-polarized light through the 1 / 2λ plate, the incident illumination light 1 is converted into S-polarized light and then output as the illumination light 2.

Although a mercury lamp is assumed here as the light source 11, a laser light source including a plurality of sub light sources may be used. In that case, the polarization converter 12 is not always necessary.
The illumination light 2 converted into S-polarized light by the polarization conversion unit 12 is incident on the wheel-type wavelength selective polarization conversion unit 13. The illumination light 2 incident on the wheel type wavelength selective polarization converter 13 illustrated in FIG. 2 is blue (B) specific wavelength polarized light by the rotation of the wheel type wavelength selective polarization converter 13 controlled by a control device (not shown). The conversion element and the green (G) specific wavelength polarization conversion element are alternately transmitted. As a result, the illumination light 3 transmitted through the wheel-type wavelength selective polarization conversion unit 13 is transmitted through the blue (B) specific wavelength polarization conversion element, and only the polarization direction of the blue (B) component is P-polarized (the other is S-polarized). It has two states, one state and a state where the green (G) specific wavelength polarization conversion element is transmitted, and only the polarization direction of the green (G) component is P-polarized light (otherwise it is S-polarized light). .

As will be described in detail later, the wavelength component converted here is removed as unnecessary light 4 before reaching a screen (not shown).
The illumination light 3 that has passed through the wheel-type wavelength selective polarization conversion unit 13 enters the color separation / combination unit 20 in the state of P-polarized light only in the blue (B) or green (G) component. 3A to 3G, after entering the color separation / combination unit 20, the light is modulated by the first spatial light modulator 15 or the second spatial light modulator 16 and projected onto a screen (not shown) as projection light 5. It is the figure which showed the optical path of each of the red (R) component, blue (B) component, and green (G) component contained in the illumination light 3 until. Hereinafter, a description will be given with reference to FIGS. 3A to 3G.

  First, the case of the illumination light 3 that is transmitted through the blue (B) specific wavelength polarization conversion element and is in the P-polarized state only in the polarization direction of the blue (B) component will be described. As shown in FIG. 3A, the illumination light 3 incident on the prism 21 constituting the color separation / combination unit 20 is incident on an R transmission type dichroic film 23 disposed on a part of the joint surface. The red (R) component of the illumination light 3 passes through the dichroic film 23 and enters the first spatial light modulator 15 at a predetermined angle. The other blue (B) and green (G) components are reflected by the dichroic film 23 and totally reflected by the incident surface of the prism 21, and then enter the second spatial light modulator 16 at a predetermined angle.

  The incident angle of the illumination light 3 to the dichroic film 23 is designed in advance so as to obtain good characteristics as an R transmission type. Thereby, the dichroic film 23 can color-separate the red (R) component of the illumination light 3 and the other components with high accuracy.

  Further, as described above, since the dichroic film 23 is a dichroic film that is predominantly S-polarized, good characteristics can be obtained in a relatively wide range with respect to the incident angle. For this reason, even when the incident angle with respect to the dichroic film varies due to the light flux having a predetermined NA, the deterioration of characteristics of the red (R) and green (G) components in the S-polarized state is minimized. Thus, color separation is performed with high accuracy, and the light reaches the first spatial light modulator 15 and the second spatial light modulator 16, respectively.

  On the other hand, the blue (B) component in the P-polarized state has a large deterioration in the characteristics of the dichroic film 23 due to the incident angle, so that depending on the incident angle, the color is different from the red (R) and green (G) components in the S-polarized state. Separation accuracy decreases. However, as described later in detail, the component that was P-polarized at the time of incidence on the dichroic film 23 is removed from the projection light 5 as unnecessary light 4 by the polarizing film 24. This does not affect the color reproducibility of the recorded video.

  FIG. 3B is a diagram showing only the optical path of the red (R) component after being incident on the first spatial light modulator 15. The red (R) component incident on the first spatial light modulator 15 is generated at each pixel portion of the first spatial light modulator 15 based on a control signal related to a red (R) component received from a control circuit (not shown). Modulated and reflected in the normal direction by the amount of light required for each pixel.

  At this time, the red (R) component travels back and forth through the quarter-λ plate 14 disposed on the optical path between the color separation / synthesis unit 20 and the first spatial light modulator 15, so that the polarization direction is 90. Rotate the angle to convert from S-polarized light to P-polarized light. The red (R) component converted into P-polarized light again enters the color separation / synthesis unit 20, passes through the P-polarized transmission type polarizing film 24, and is projected as projection light 5.

  In addition, the incident angle to the polarizing film 24 is designed in advance so as to obtain good characteristics as a P-polarized transmission type. Thereby, the polarization film 24 can remove the component transmitted through the dichroic film 23 by the P-polarized light from the projection light with high accuracy in consideration of the change of the polarization direction at the ¼λ plate 14. For example, the blue (B) component of P-polarized light that has entered the first spatial light modulator 15 due to the deterioration of the characteristics of the dichroic film 23 described above can be removed.

  Further, the ¼λ plate 14 may be a specific wavelength polarization conversion element that functions as a ¼λ plate in a wavelength selective manner only for the red (R) component. In this case, components transmitted through the dichroic film 23 with S-polarized light (except for the red (R) component) can be removed from the projection light. For example, a green (G) component transmitted by S-polarized light due to an error in color separation accuracy of the dichroic film 23 can be removed from the projection light by the polarizing film 24 that reflects S-polarized light. The specific wavelength polarization conversion element that functions as a ¼λ plate wavelength-selectively only for the red (R) component only needs to secure characteristics in a narrow wavelength range as compared with a normal ¼λ plate. Is easily secured.

  FIG. 3C is a diagram illustrating optical paths of blue (B) and green (G) components after entering the second spatial light modulator 16. The blue (B) and green (G) components after entering the second spatial light modulator 16 are generated in each pixel unit of the second spatial light modulator 16 based on a control signal received from a control circuit (not shown). Modulated and reflected in the normal direction by the amount of light required for each pixel.

  A control circuit (not shown) controls the second spatial light modulator 16 in synchronization with the rotation of the wheel type wavelength selective polarization converter 13. More specifically, the control circuit (not shown) controls the green (G) component when the illumination light 2 passes through the blue (B) specific wavelength polarization conversion element when the specific wavelength polarization conversion element is switched. When the signal passes through the green (G) specific wavelength polarization conversion element, a control signal related to the blue (B) component is transmitted to the second spatial light modulator 16.

  Thereby, in the second spatial light modulator 16, a component (here, green (G) component different from the component whose polarization direction is converted by the wheel type wavelength selective polarization conversion unit 13 and later removed from the projection light 5 is used. ) To be modulated based on the control signal.

  The blue (B) and green (G) components modulated by the second spatial light modulator 16 are incident on the color separation / synthesis unit 20 again, and once totally reflected by the prism 21, and then the P-polarized transmission type polarized light. The light enters the film 24. The incident angle to the polarizing film 24 is designed in advance so as to obtain good characteristics as a P-polarized transmission type. Thereby, the green (G) component of S-polarized light is reflected by the polarizing film 24 and projected as the projection light 5, and the blue (B) component of P-polarized light is transmitted through the polarizing film 24 and removed as unnecessary light 4. It will be.

  In this way, the illumination light 3 that has entered the color separation / combination unit 20 in the state of P polarization only in the polarization direction of the blue (B) component has red (R) and green (G) components as shown in FIG. 3D. The light is synthesized by the polarizing film 24 and projected onto a screen (not shown) as projection light 5.

Next, the case of the illumination light 3 that passes through the green (G) specific wavelength polarization conversion element and is in the P-polarized state only in the polarization direction of the green (G) component will be described.
As shown in FIG. 3E, the illumination light 3 incident on the color separation / synthesis unit 20 is color-separated by the dichroic film 23 as in FIG. 3A, and the red (R) component is the first spatial light modulator 15. The other blue (B) and green (G) components are incident on the second spatial light modulator 16.

  Note that since the dichroic film 23 is a dichroic film that is predominantly S-polarized, the accuracy of color separation of the green (G) component, which is P-polarized light, is likely to deteriorate compared to other components. For this reason, some green (G) components may be incident on the first spatial light modulator 15, but either of the first spatial light modulator 15 or the second spatial light modulator 16. Even if the image is separated in this direction, it is removed by the polarizing film 24 thereafter, so that the color reproducibility of the displayed image is not affected.

Similarly to FIG. 3B, the red (R) component is modulated by the first spatial light modulator 15, converted to P-polarized light by the ¼λ plate 14, and then transmitted through the polarizing film 24 as projection light 5. Projected.
On the other hand, the blue (B) and green (G) components after entering the second spatial light modulator 16 are modulated based on the control signal related to the blue (B) component in synchronization with the wheel-type wavelength selective polarization converter 13. Will be. Thereafter, as shown in FIG. 3F, the blue (B) component of S-polarized light is reflected by the polarizing film 24 and projected as projection light 5, and the green (G) component of P-polarized light is transmitted through the polarizing film 24 and becomes unnecessary light. 4 will be removed.

  In this way, the illumination light 3 that has entered the color separation / combination unit 20 in the state of P polarization only in the polarization direction of the green (G) component has red (R) and blue (B) components as shown in FIG. 3G. The light is synthesized by the polarizing film 24 and projected onto a screen (not shown) as projection light 5.

  As described above, in the present embodiment, the illumination light 2 is alternately transmitted through the green (G) specific wavelength polarization conversion element and the blue (B) specific wavelength polarization conversion element, so that the red (R) component and the blue (B) component are transmitted. The synthesized light and the synthesized light of the red (R) component and the green (G) component are alternately projected to display a color image.

  In this embodiment, the dichroic film 23 acts only on the illumination light 3, and the polarizing film 24 acts only on the projection light 5. For this reason, it is easier to optimize the incident angle of the dichroic film 23 and the polarizing film 24 than when acting on both illumination light and projection light, and the deviation from the optimum incident angle can be reduced. It is possible to suppress deterioration of the characteristics. This contributes to realization of high color reproducibility and reduction of light quantity loss.

  In this embodiment, the projection light 5 is selectively output using the polarization state. However, the wavelength component used as the projection light 5 is a polarization direction (S-polarized light) in which the dichroic film 23 exhibits good characteristics. By entering the dichroic film 23, it is possible to further suppress the deterioration of the characteristics depending on the incident angle. Such a dichroic film exhibiting good characteristics for specific polarized light is generally easier to design and obtains better characteristics than a dichroic film exhibiting good characteristics for both P-polarized light and S-polarized light. be able to. It should be noted that a dichroic film is preferably generated as a lugate filter or an inclined film because it exhibits smooth and steep wavelength dependence with little ripple and a high degree of design freedom.

  The color separation / combination unit 20 of the present embodiment also realizes separation of illumination light and projection light in addition to color separation / combination with two prisms. For this reason, compared with the case where these are performed by separate TIR prisms or PBS prisms, both the types and the number of prisms can be reduced, and the advantages of simplification of the optical system and cost can be obtained. In particular, the removal of the TIR prism contributes to an improvement in the burden of high-precision holding of the minute internal gap and the light amount loss and aberration generated when light passes through the gap.

  In addition, since the dichroic film 23 and the polarizing film 24 are formed on the same plane in the color separation / combination unit 20 of the present embodiment, it is easy to manufacture the film and handle the prism associated therewith, or use a spatial light modulator. Since the number of reflections from the modulation to the projection is an even number regardless of the optical path, there is an advantage that it is not necessary to be aware of the inversion of the image.

  Until now, the spatial light modulator is a micromirror device, and as illustrated in FIG. 4A, the normal line of the micromirror plane in a state before the micromirror is controlled (hereinafter referred to as an initial state). In this example, the illumination light 3 incident from an oblique direction at a predetermined angle is reflected in the normal direction as ON light by a necessary amount. However, the reflection direction is not particularly limited to this. As illustrated in FIG. 4B, the illumination light 3 incident from the oblique direction at a predetermined angle different from that in FIG. 4A with respect to the normal line of the micromirror plane in the initial state is reflected in the oblique direction as a required amount of light as ON light. You may comprise. In this case, there is an advantage that the directions of the illumination light 3 and the projection light 5 can be easily separated.

  Furthermore, as described above, the wheel-type wavelength selective polarization converter 13 is not limited to the configuration illustrated in FIG. 5A to 5E are modified examples of the wheel-type wavelength selective polarization converter 13.

  The wheel-type wavelength selective polarization converter 31 illustrated in FIG. 5A is an example configured using one blue (B) specific wavelength polarization conversion element 31a and one green (G) specific wavelength polarization conversion element 31b.

  The wheel type wavelength selective polarization conversion unit 32 illustrated in FIG. 5B includes green (G) and blue (B) in addition to the blue (B) specific wavelength polarization conversion element 32a and the green (G) specific wavelength polarization conversion element 32b. In this example, a cyan (C) specific wavelength polarization conversion element 32c that converts the polarization directions of both components is used. In this case, while transmitting through the cyan (C) specific wavelength polarization conversion element 32c, both the green (G) and blue (B) components are excluded as unnecessary light 4, and the green (G) and blue (B ) The light quantity of the component can be adjusted.

  The wheel-type wavelength selective polarization converter 33 illustrated in FIG. 5C uses a transparent flat plate 33c having no polarization action in addition to the blue (B) specific wavelength polarization conversion element 33a and the green (G) specific wavelength polarization conversion element 33b. This is an example configured. In this case, while transmitting through the transparent flat plate 33c, both the green (G) and blue (B) components are projected as the projection light 5, and a brighter image can be obtained.

In addition, the ratio of the specific wavelength polarization conversion elements of green (G) and blue (B) can be variously adjusted in consideration of white balance.
For example, when the light source 11 is a mercury lamp, the light quantity of the red (R) component tends to be insufficient, so that the white balance is taken into consideration while always projecting the red (R) component as in this embodiment. Thus, the green (G) and blue (B) components may be projected alternately at a ratio of about 7: 3 to 5: 5.

Further, the component that is always projected is not limited to the red (R) component. FIG. 5D and FIG. 5E show a configuration in the case of always projecting a green (G) component and a blue (B) component, respectively.
By changing the configuration of the wheel-type wavelength selective polarization converter 13 as described above, it is possible to adjust the ratio and light amount of each color component in consideration of various factors such as the type of light source and human visibility.

  Further, instead of the wheel-type wavelength selective polarization converter 13, a drum-type wavelength selective polarization converter 36 may be used. When the drum-type wavelength selective polarization conversion unit 36 illustrated in FIG. 6 in which the specific wavelength polarization conversion element is arranged on the surface of the cylinder is used, the illumination light 2 passes through the specific wavelength polarization conversion element on the cylinder surface from the outside of the cylinder and is cylindrical. The light enters the inside, is reflected by a mirror or the like disposed in the cylinder, and exits from a surface where the specific wavelength polarization conversion element is not disposed. The rotation of the drum-type wavelength selective polarization converter 36 is controlled by a control device (not shown), and the illumination light 2 is a green specific wavelength polarization conversion element (specific wavelength polarization conversion element 36a, specific wavelength polarization conversion element 36c) and blue specific. By alternately transmitting the wavelength polarization conversion elements (specific wavelength polarization conversion element 36b, specific wavelength polarization conversion element 36d), the same effect as the wheel type wavelength selective polarization conversion unit 13 is obtained.

  In the case of the drum-type wavelength selective polarization conversion unit 36, the relative positional relationship between the polarization direction of the incident light (illumination light 2) and the direction of the reference axis 36e of the specific wavelength polarization conversion element indicated by the bidirectional arrow in FIG. 6 is always constant. Therefore, both directions can always be made to coincide with each other, and the polarization direction of light can be converted in a wavelength selective manner most efficiently.

  Further, instead of the wheel type wavelength selective polarization converter 13, a slide type wavelength selective polarization converter 37 may be used. The slidable wavelength selective polarization conversion unit 37 includes specific wavelength polarization conversion elements (specific wavelength polarization conversion element 37a, specific wavelength polarization conversion element 37b, specific wavelength polarization conversion element 37c) arranged in a certain direction as illustrated in FIG. ) Is switched to switch the specific wavelength polarization conversion element through which the illumination light 2 is transmitted.

  In the case of the slide-type wavelength selective polarization conversion unit 37 as well as the drum type wavelength selection polarization conversion unit 36, the polarization direction of the incident light (illumination light 2) and the reference of the specific wavelength polarization conversion element indicated by the bidirectional arrow in FIG. Since the relative positional relationship in the direction of the axis 37e is always constant, both directions can always be made coincident, and the polarization direction of light can be converted in a wavelength selective manner most efficiently.

  Note that in any case of the drum-type wavelength selective polarization converter 36 and the slide-type wavelength selective polarization converter 37, as with the wheel-type wavelength selective polarization converter 13, the combination regarding the wavelength component (color) that acts is arbitrary. You can choose.

In addition, instead of the wheel-type wavelength selective polarization conversion unit 13, for example, a color switch of color link or an electronic color switch of Rolic Technologies Ltd. in Alschville, Switzerland, is used to electrically control the wavelength component for converting the polarization direction. Electronic color-specific polarization control means that can be switched by the above method may be used.
[First Modification of First Embodiment]
In the first modification of the first embodiment, the illumination light 1 is converted into P-polarized light by the polarization conversion unit 12.

  FIG. 8 is a diagram illustrating a part of the configuration of the two-plate projection device 100 in the present modification, and shows the optical paths of the respective color components when transmitted through the green (G) specific wavelength polarization conversion element. The basic configuration is the same as the configuration shown in FIG. 1 except for the following three points, and the optical path of each color component is also the same. Hereinafter, differences from the first embodiment will be described with reference to FIG.

  The first difference is that the polarization conversion unit 12 performs polarization conversion to P-polarized light. As a result, the specific wavelength polarization conversion element used in the wheel-type wavelength selective polarization conversion unit 13 converts the polarization state of the specific wavelength from P-polarized light to S-polarized light. In addition, about the combination regarding the wavelength component (color) which acts, the structure similar to FIG. 2 can be used.

  The second difference is that the dichroic film 23 is a dichroic film predominantly P-polarized. In this modification, since the wavelength component used as the projection light 5 is incident on the dichroic film 23 in the P-polarized state, a P-polarized dichroic film having better characteristics with respect to the P-polarized light is used.

  The third difference is that the ¼λ plate 14 is not on the optical path of the red (R) component between the color separation / combination unit 20 and the first spatial light modulator 15, but the color separation / combination unit 20 and the second This is a point arranged on the optical path of the green (G) and blue (B) components between the spatial light modulators 16. This is a measure for adjusting the difference in action in the polarizing film 24 that occurs when the configuration of FIG. 1 is applied as it is because the polarization state of the illumination light 3 is orthogonal to the case of FIG. As a result, the polarization state at the time of incidence on the polarizing film 24 becomes the same as in FIG. 1, and the green (G) component and the blue (B) component are always projected while the red (R) component is always projected as in FIG. It can be projected alternately.

Note that the ¼λ plate 14 may be a cyan (C) specific wavelength polarization conversion element that functions as a ¼λ plate wavelength-selectively only for the green (G) and blue (B) components.
With the above configuration, even when the illumination light 1 is converted to P-polarized light by the polarization conversion unit 12, the same effects as those of the first embodiment can be obtained.
[Second Modification of First Embodiment]
In the second modification of the first embodiment, the dichroic film 23 is changed to an R reflection type dichroic film.

  FIG. 9 is a diagram illustrating a part of the configuration of the two-plate projection device 100 in the present modification, and shows the optical paths of the respective color components when transmitted through the blue (B) specific wavelength polarization conversion element. The basic configuration is the same as the configuration shown in FIG. 1 except for the dichroic film 23. The dichroic film 23 is the same as that shown in FIG. Hereinafter, differences from the first embodiment will be described with reference to FIG.

  The difference from the first embodiment is only that the optical path of each color component after entering the dichroic film 23 is different because the dichroic film 23 is an R reflection type. More specifically, as shown in FIG. 9, the red (R) component is guided to the optical path incident on the second spatial light modulator 16, and the green (G) and blue (B) components are in the first space. The light is guided to an optical path incident on the optical modulator 15.

  The quarter λ plate 14 is disposed at the same location as in FIG. 1, but the components that act are different from those in FIG. As a result, when a specific wavelength polarization conversion element is used for the quarter λ plate 14, it is necessary to use a cyan (C) specific wavelength polarization conversion element that acts as a quarter λ plate in a wavelength selective manner only for the cyan (C) component. is there.

With the above configuration, even when the dichroic film 23 is changed to an R reflection type dichroic film, the same effects as those of the first embodiment can be obtained.
[Third Modification of First Embodiment]
In the third modification of the first embodiment, the illumination light 1 is converted into P-polarized light by the polarization conversion unit 12, and the dichroic film 23 is changed to an R reflection type dichroic film.

  FIG. 10 is a diagram illustrating a part of the configuration of the two-plate projection device 100 in the present modification, and shows the optical path of each color component when transmitted through the blue (B) specific wavelength polarization conversion element. The basic configuration is the same as the configuration shown in FIG. 1 except for the four points described below. Hereinafter, differences from the first embodiment will be described with reference to FIG.

  The first difference is that the polarization conversion unit 12 performs polarization conversion to P-polarized light. As a result, the specific wavelength polarization conversion element used in the wheel-type wavelength selective polarization conversion unit 13 converts the polarization state of the specific wavelength from P-polarized light to S-polarized light. In addition, about the combination regarding the wavelength component (color) which acts, the structure similar to FIG. 2 can be used.

  The second difference is that the dichroic film 23 is a dichroic film predominantly P-polarized. In this modification, since the wavelength component used as the projection light 5 is incident on the dichroic film 23 in the P-polarized state, a P-polarized dichroic film having better characteristics with respect to the P-polarized light is used.

  The third difference is that the optical path of each color component after entering the dichroic film 23 is different because the dichroic film 23 is an R reflection type. More specifically, as shown in FIG. 10, the red (R) component is guided to the optical path incident on the second spatial light modulator 16, and the green (G) and blue (B) components are in the first space. The light is guided to an optical path incident on the optical modulator 15.

  The fourth difference is that the ¼λ plate 14 is not arranged between the color separation / synthesis unit 20 and the first spatial light modulator 15 but between the color separation / synthesis unit 20 and the second spatial light modulator 16. It is a point that has been. This is a measure for adjusting the difference in action in the polarizing film 24 that occurs when the configuration of FIG. 1 is applied as it is because the polarization state of the illumination light 3 is orthogonal to the case of FIG. Accordingly, as in FIG. 1, the green (G) component and the blue (B) component can be alternately projected while always projecting the red (R) component.

Note that the ¼λ plate 14 may be a red (R) specific wavelength polarization conversion element that functions as a ¼λ plate with wavelength selection only for the red (R) component.
With the above configuration, even when the illumination light 1 is converted to P-polarized light by the polarization conversion unit 12 and the dichroic film 23 is changed to an R reflection type dichroic film, Similar effects can be obtained.

The present embodiment and the first to third modifications have a relationship in which the polarization state of the illumination light 2 and the characteristics of the dichroic film 23 are changed to various combinations.
[Fourth Modification of First Embodiment]
In the fourth modification of the first embodiment, the ¼λ plate 14 in the first embodiment is changed to a ½λ plate 17.

  FIG. 11 is a diagram exemplifying a part of the configuration of the two-plate projection device 100 in the present modification, and shows the optical paths of the respective color components when transmitted through the blue (B) specific wavelength polarization conversion element. The basic configuration is the same as the configuration shown in FIG. 1 except for the points described later, and the optical path of each color component is also the same. Hereinafter, differences from the first embodiment will be described with reference to FIG.

  The difference from the first embodiment is that the λλ plate 14 is changed from the λλ plate 14 to the ½λ plate 17, and accordingly, the arrangement is changed from a position that acts both before and after incidence to the spatial light modulator to one side. It is the point which changed to the position which acts only. This is due to the fact that in the first embodiment, the polarization direction conversion obtained by transmitting twice through the quarter λ plate 14 can be obtained with one transmission through the ½λ plate 17. FIG. 11 shows an example in which the first spatial light modulator 15 is arranged on the optical path before entering the first spatial light modulator 15, but if it is transmitted through the dichroic film 23 and before entering the polarizing film 24, the first You may arrange | position in other places, such as on the optical path after reflection from the spatial light modulator 15. FIG.

Note that the ½λ plate 17 may be a red (R) specific wavelength polarization conversion element that functions as a ½λ plate in a wavelength selective manner only for the red (R) component.
With the above configuration, even when the ¼λ plate 14 is changed to the ½λ plate 17, the same effect as that of the first embodiment can be obtained.

Also in the configuration using the ½λ plate 17 as in the present modification, the polarization state of the illumination light 2 and the characteristics of the dichroic film 23 are similar to those in the first to third modifications of the first embodiment. It can be changed to various combinations.
[Second Embodiment]
In the present embodiment, the polarization direction included in the projection light 5 is aligned in a certain direction with respect to the first embodiment described above.

  FIG. 12 is a diagram illustrating the configuration of the two-plate type projector 200 according to the present embodiment, and shows the optical path of each color component when transmitted through the blue (B) specific wavelength polarization conversion element. In the projector 200, a red specific wavelength polarization conversion element 25 that converts a red (R) component from P-polarized light to S-polarized light is added between the color separation / synthesis unit 20 and a screen (not shown). Other configurations are the same as those of the projection apparatus 100.

  Until the illumination light 3 is modulated by the first spatial light modulator 15 and the second spatial light modulator 16 and synthesized by the polarizing film 24, it is the same as in the first embodiment. Only the subsequent steps will be described.

  In the case of this configuration, a P-polarized red (R) component transmitted through the polarizing film 24 and a S-polarized green (G) component or blue (B) component reflected from the polarizing film 24 by the P-polarized transmission type polarizing film 24. The combined light reaches the red specific wavelength polarization conversion element 25. Since the red specific wavelength polarization conversion element 25 rotates only the red (R) component wavelength-selectively by 90 degrees, the red (R) component is converted from P-polarized light to S-polarized light. For this reason, all the projection lights 5 are unified to S polarization.

  As described above, in this embodiment, by using the polarizing screen together, the contrast of the image can be improved in addition to the effects of the first embodiment. Here, the polarizing screen is a screen that reflects only a component of a predetermined polarization direction and can prevent reflection of extraneous light having a different polarization direction.

  Instead of the red specific wavelength polarization conversion element 25, a cyan specific wavelength polarization conversion element that rotates the polarization planes of both the green (G) component and the blue (B) component may be used. In that case, the cyan specific wavelength polarization conversion element converts the polarization state of cyan from S-polarized light to P-polarized light.

Further, this embodiment can be modified in the same manner as the first embodiment. Specifically, the first spatial light modulator 15 and the second spatial light modulator 16 may be used in an oblique illumination oblique reflection configuration. Further, the configuration of the wheel-type wavelength selective polarization converter 13 is changed, the drum-type wavelength selective polarization converter 36, the slide-type wavelength selective polarization converter 37, the electronic color-specific polarization instead of the wheel-type wavelength selective polarization converter 13. Control means may be used. Furthermore, the polarization state of the illumination light 2 and the characteristics of the dichroic film 23 can be changed to various combinations. However, in that case, the red specific wavelength polarization conversion element 25 or the cyan specific wavelength polarization conversion element converts the S polarization into the P polarization by the specific wavelength polarization conversion element or the P polarization by the specific wavelength polarization conversion element depending on the combination. It shall be converted to S-polarized light.
[First Modification of Second Embodiment]
In the first modification of the second embodiment, the function of aligning the polarization direction included in the projection light 5 in a certain direction is realized by changing the configuration of the projection device 200 as in the second embodiment. is there.

  FIG. 13 is a diagram illustrating a part of the configuration of the two-plate projection device 200 in the present modification, and shows the optical path of each color component when transmitted through the blue (B) specific wavelength polarization conversion element. Differences in configuration from the second embodiment are the following three points.

The first difference is that the ¼λ plate 14 disposed between the color separation / synthesis unit 20 and the first spatial light modulator 15 is removed.
The second difference is that the polarizing film 24 disposed in the color separation / combination unit 20 is changed to a dichroic film 26 that is R transmission type and has S polarization predominance.

The third difference is that the red specific wavelength polarization conversion element 25 between the color separation / synthesis unit 20 and the screen is changed to a polarizing plate 27 that transmits only S-polarized light.
Hereinafter, with reference to FIG. 13, regarding the flow until the illumination light 3 incident on the color separation / synthesis unit 20 is projected as projection light 5 on a screen (not shown) This will be described together with the action.

  The illumination light 3 that has entered the color separation / combination unit 20 is reflected only by the red (R) component at the R transmission type dichroic film 23, so that the red (R) component and others (green (G) and blue (B) And are incident on the first spatial light modulator 15 and the second spatial light modulator 16 at predetermined angles, respectively.

  The red (R) component modulated by each pixel portion of the first spatial light modulator 15 and reflected in the normal direction by the amount of light required for each pixel is another one arranged on the same plane as the dichroic film 23. The light enters the dichroic film 26. Therefore, the red (R) component passes through the dichroic film 26 and is emitted from the color separation / synthesis unit 20 in the S-polarized state.

  On the other hand, the green (G) and blue (B) components modulated by the respective pixel portions of the second spatial light modulator 16 and reflected in the normal direction by the amount of light necessary for each pixel are once totally reflected by the prism 21. Then, the light enters the dichroic film 26. The dichroic film 26 reflects both the green (G) and blue (B) components and emits them from the color separation / synthesis unit 20 in the S-polarized and P-polarized states, respectively.

  Thereafter, each color component synthesized by the dichroic film 26 and emitted from the color separation / synthesis unit 20 enters the polarizing plate 27. Since the polarizing plate 27 has a characteristic of transmitting only S-polarized light, the blue (B) component that is P-polarized light is removed as unnecessary light 4, and the remaining red (R) and green (G) components are projected as projection light 5. Will be.

  When only the green (G) component is incident on the color separation / synthesis unit 20 in the P-polarized state, the green (G) component is P-polarized and the blue (B) component is S-polarized and reaches the polarizing plate 27. Therefore, the green (G) component that is P-polarized light is removed as unnecessary light 4, and the remaining red (R) and blue (B) components are projected as projection light 5.

  Also with the above configuration, since the polarization state of the projection light 5 can be unified, the contrast of the image can be improved by using the polarization screen together as in the second embodiment. Moreover, the effect of 1st Embodiment can be acquired similarly.

  Also in this modification, the polarization state of the illumination light 2 can be changed to P-polarized light. In this case, the polarizing plate 27 is changed to a polarizing plate 27 that transmits only P-polarized light, and the dichroic film 23 and the dichroic film 26 are changed to dichroic films that are predominantly P-polarized.

  Further, the dichroic film 23 and the dichroic film 26 can be changed from the R transmission type to the R reflection type. However, it is necessary to change both the dichroic film 23 and the dichroic film 26 to those of R reflection type characteristics.

In addition, the first spatial light modulator 15 and the second spatial light modulator 16 may be used in an oblique illumination oblique reflection configuration. Further, the configuration of the wheel-type wavelength selective polarization converter 13 is changed, the drum-type wavelength selective polarization converter 36, the slide-type wavelength selective polarization converter 37, the electronic color-specific polarization instead of the wheel-type wavelength selective polarization converter 13. Control means may be used.
[Third Embodiment]
In the present embodiment, a field lens is added between the color separation / synthesis unit 20 and the spatial light modulator, compared to the second embodiment described above.

  FIG. 14 is a diagram illustrating the configuration of the two-plate type projector 300 in the present embodiment, and shows the optical path of each color component when transmitted through the blue (B) specific wavelength polarization conversion element. In the projection apparatus 300, a field lens 28 is added between the color separation / synthesis unit 20 and the first spatial light modulator 15, and a field lens 29 is added between the color separation / synthesis unit 20 and the second spatial light modulator 16. ing. Other configurations are the same as those of the projection apparatus 200.

  The field lens 28 and a projection lens (not shown) act as a projection optical system for the first spatial light modulator 15 and are a telecentric optical system for the first spatial light modulator 15. Similarly, the field lens 29 and a projection lens (not shown) also function as a projection optical system for the second spatial light modulator 16, and are telecentric optical systems for the second spatial light modulator 16. .

  By configuring the projection optical system as a telecentric optical system using a field lens, the entrance pupil position of the projection lens (not shown) can be brought closer to the spatial light modulator side, so that the beam diameter in the projection optical system is reduced. Can do. As a result, the color separation / combination unit 20 and a projection lens (not shown) can be downsized.

  FIGS. 15A and 15B are diagrams showing the state of the principal ray 6 when the entrance pupil position of the projection lens is changed. The entrance pupil position of the projection lens may be positioned closer to the projection lens (including the inside of the projection lens) than the polarizing film 24 as illustrated in FIG. 15A, or positioned near the polarizing film 24 as illustrated in FIG. 15B. May be. In addition, when it is located closer to the projection lens than the polarizing film 24 as shown in FIG. 15A, it is effective to reduce the effective diameter of the projection lens, whereas it is located near the polarizing film 24 as shown in FIG. 15B. The color separation / combination unit 20 can be effectively reduced in size.

  The addition of the field lens 28 (field lens 29) is also effective for correcting aberrations. Since both field lenses act once each before and after modulation by the spatial light modulator, each field lens contributes to correction of aberrations of both the illumination light 3 and the projection light 5. Further, by changing the configuration according to the wavelength components acting on the field lens 28 and the field lens 29, chromatic aberration can be corrected well.

  As described above, in this embodiment, by using a field lens, in addition to the effects of the second embodiment, effects such as downsizing of the projection lens and the color separation / synthesis unit 20 and correction of aberrations (including chromatic aberration) are obtained. It is done.

Further, the present embodiment can be modified in the same manner as the second embodiment. Specifically, the first spatial light modulator 15 and the second spatial light modulator 16 may be used in an oblique illumination oblique reflection configuration. Further, the configuration of the wheel-type wavelength selective polarization converter 13 is changed, the drum-type wavelength selective polarization converter 36, the slide-type wavelength selective polarization converter 37, the electronic color-specific polarization instead of the wheel-type wavelength selective polarization converter 13. Control means may be used. Furthermore, the polarization state of the illumination light 2 and the characteristics of the dichroic film 23 can be changed to various combinations.
[Fourth Embodiment]
In the present embodiment, the shape and the like of the prism constituting the color separation / combination unit 20 are changed with respect to the first embodiment described above.

  FIG. 16 is a diagram illustrating the configuration of the two-plate projection device 400 in this embodiment, and shows the optical path of each color component when transmitted through a blue (B) specific wavelength polarization conversion element. The projection apparatus 400 is the same as the projection apparatus 100 except for the shape of the prism used in the color separation / synthesis unit 20 and the arrangement of the quarter λ plate 14.

  The color separation / combination unit 20 is composed of two triangular prisms (prism 41, prism 42) having the same cross-sectional shape and a triangular prism shape as a whole as shown in FIG. The same is true in that an R-transmissive dichroic film 23 and a P-polarized transmissive polarizing film 24 are disposed on the joint surface of the prism, and that the dichroic film 23 is an S-polarized dichroic film. The quarter-λ plate 14 is disposed on the optical path between the color separation / combination unit 20 and the second spatial light modulator 16.

Hereinafter, the flow until the illumination light 3 incident on the color separation / synthesis unit 20 is projected as projection light 5 on a screen (not shown) will be described with reference to FIGS. 17A and 17B.
FIG. 17A is a diagram illustrating optical paths of the respective color components before being incident on the first spatial light modulator 15 and the second spatial light modulator 16. The illumination light 3 incident on the color separation / combination unit 20 from the long side surface of the prism 41 with only the blue (B) component in the P-polarized state is incident on the R transmission type dichroic film 23 arranged on a part of the joint surface. To do. The red (R) component of the illumination light 3 passes through the dichroic film 23, is totally reflected by the long side surface of the prism 42, and enters the first spatial light modulator 15 at a predetermined angle. The other blue (B) and green (G) components are reflected by the dichroic film 23 and totally reflected by the incident surface (long side surface) of the prism 41, and then the second spatial light modulator at a predetermined angle. 16 is incident.

  Note that the dichroic film 23 is a dichroic film predominantly of S-polarized light, and the incident angle of the illumination light 3 to the dichroic film 23 is designed in advance so that a good characteristic can be obtained, as in the first embodiment. is there.

  FIG. 17B is a diagram illustrating the optical paths of the respective color components after entering the first spatial light modulator 15 and the second spatial light modulator 16. The red (R) component modulated by each pixel unit of the first spatial light modulator 15 and reflected in the normal direction by the amount of light necessary for each pixel is totally reflected by the long side surface of the prism 42 and is polarized. 24 is incident. Since the polarizing film 24 is a P-polarized transmission type polarizing film, the red (R) component is reflected by the polarizing film 24 and is emitted from the color separation / synthesis unit 20 in the S-polarized state.

  On the other hand, the green (G) and blue (B) components modulated by the respective pixel portions of the second spatial light modulator 16 and reflected in the normal direction by the amount of light necessary for each pixel are once totally reflected by the prism 41. Then, the light enters the polarizing film 24. At this time, the green (G) and blue (B) components reciprocate on the quarter λ plate 14 disposed on the optical path between the color separation / synthesis unit 20 and the second spatial light modulator 16. Therefore, the polarization direction is rotated by 90 degrees and converted from S-polarized light to P-polarized light and from P-polarized light to S-polarized light, respectively. Since the polarizing film 24 is a P-polarized transmission type polarizing film, the blue (B) component converted into S-polarized light is reflected by the polarizing film 24 and removed as unnecessary light 4, while green converted into P-polarized light. The component (G) passes through the polarizing film 24 and is emitted from the color separation / synthesis unit 20.

Thereafter, the S-polarized red (R) component and the P-polarized green (G) component synthesized by the polarizing film 24 and emitted from the color separation / synthesis unit 20 are projected as the projection light 5.
When only the green (G) component is incident on the color separation / synthesis unit 20 in the P-polarized state, the green (G) component is S-polarized light and the blue (B) component is P-polarized light. Therefore, the green (G) component that is S-polarized light is removed as unnecessary light 4, and the red (R) component of S-polarized light and the blue (B) component of P-polarized light are projected as projection light 5.

  Note that the number of reflections from the modulation by the spatial light modulator to the projection is two when the first spatial light modulator 15 modulates, but 1 when the second spatial light modulator 16 modulates. It has become times. For this reason, in order to prevent inversion of the image displayed by the projection light 5, the images generated by the first spatial light modulator 15 and the second spatial light modulator 16 are respectively illustrated in FIG. 17B. It is necessary to generate the video image 15a and the video direction 16a so as to be reversed in advance.

  As described above, the configuration of the present embodiment can provide the same effects as those of the first embodiment except that it is necessary to cope with the above-described video inversion. In the case of this embodiment, in addition to the effect of the first embodiment, there is an advantage that the directions of the illumination light 3 and the projection light 5 can be changed greatly. In addition, since the first spatial light modulator 15 and the second spatial light modulator 16 can be arranged on the same plane, the first spatial light modulator 15 and the second spatial light modulator 16 are provided as one. By making a chip, the burden required for packaging can be reduced. In addition, since only one type of prism is required for the color separation / synthesis unit 20 and a simple triangular prism shape, an effect of cost reduction can be obtained.

  Also in this embodiment, as in the case of the first embodiment, the polarization state of the illumination light 2 and the characteristics of the dichroic film 23 can be changed to various combinations. FIG. 18A is a diagram illustrating an optical path when the illumination light 2 is changed to P-polarized light. FIG. 18B is a diagram showing an optical path when an R reflection type dichroic film is used as the dichroic film 23. FIG. 18C is a diagram showing an optical path when the illumination light 2 is changed to P-polarized light and an R reflection type dichroic film is used for the dichroic film 23. In the case of FIGS. 18A and 18C in which the illumination light 2 is changed to P-polarized light, the dichroic film 23 uses a P-polarized dichroic film, and the ¼λ plate 14 is connected to the color separation / synthesis unit 20 and the first Arranged between the spatial light modulators 15. Further, as in the case of the first embodiment, a specific wavelength polarization conversion element or a 1 / 2λ plate 17 may be used instead of the 1 / 4λ plate 14 for modification.

Further, as in the second embodiment, the specific wavelength polarization conversion element may be arranged after exiting the color separation / synthesis unit 20 so as to align the polarization direction of the projection light 5.
In addition, a field lens may be used as in the third embodiment. FIG. 19A is a diagram showing the principal ray 6 when the entrance pupil position of the projection lens is arranged in the vicinity of the polarizing film 24. FIG. 19B is a diagram showing the principal ray 6 when the entrance pupil position of the projection lens is arranged at the position after exiting the color separation / combination unit 20.

In addition, the first spatial light modulator 15 and the second spatial light modulator 16 may be used in an oblique illumination oblique reflection configuration. Further, the configuration of the wheel-type wavelength selective polarization converter 13 is changed, the drum-type wavelength selective polarization converter 36, the slide-type wavelength selective polarization converter 37, the electronic color-specific polarization instead of the wheel-type wavelength selective polarization converter 13. Control means may be used.
[First Modification of Fourth Embodiment]
In the first modification of the fourth embodiment, the relationship between the incident position of the illumination light 3 on the color separation / synthesis unit 20 and the emission position of the projection light 5 from the color separation / synthesis unit 20 is changed.

FIG. 20 is a diagram for explaining the optical path from the incidence to the emission to the color separation / combination unit 20 in the present modification, in which the illumination light 3 is represented by a solid line and the projection light 5 is represented by a broken line.
In the fourth embodiment, as shown in FIG. 16, the illumination light 3 is arranged on the upper side (position far from the bottom surface) with respect to the plane on which the spatial light modulator is arranged with respect to the polarizing film 24. In order to enter the dichroic film 23, the incident light was incident from above the projection light 5. On the other hand, in this modified example, the arrangement of the dichroic film 23 and the polarizing film 24 is changed, so that the illumination light 3 is lower than the projection light 5 (position close to the bottom surface) as shown in FIG. ).

As described above, even when the relationship between the incident position and the emission position on the color separation / combination unit 20 is changed, the same effect as in the fourth embodiment can be obtained.
Also in this modification, the same modifications as in the fourth embodiment are possible.
[Second Modification of Fourth Embodiment]
In the second modification of the fourth embodiment, the arrangement of the dichroic film 23 and the polarizing film 24 on the joint surface of the prism 41 and the prism 42 constituting the color separation / synthesis unit 20 is changed.

  FIG. 21A to FIG. 21C are diagrams for explaining the arrangement of the dichroic film 23 and the polarizing film 24 on the bonding surface, where the illumination light 3 is represented by a solid line and the projection light 5 is represented by a broken line. Here, the plane on which the triangular surface of the triangular prism 41 (prism 42) exists is the XY plane, the X-axis direction is the direction in which the spatial light modulators are aligned, and the Y-axis direction is the space. The direction is perpendicular to the optical modulator. A direction perpendicular to the XY plane is taken as a Z-axis direction. 21A, FIG. 21B, and FIG. 21C correspond to cases where the joint surface of the color separation / synthesis unit 20 is viewed from the Y, Z, and X axis directions, respectively.

The dichroic film 23 and the polarizing film 24 are separated on the YZ plane as shown in FIG. 21C.
Further, as shown in FIG. 22, the joint surface may be generated even if it is inclined with respect to the XZ plane or the XY plane.

As described above, even when the arrangement of the dichroic film 23 and the polarizing film 24 on the joint surface of the color separation / synthesis unit 20 is changed, the same effect as in the fourth embodiment can be obtained.
Also in this modification, the same modifications as in the fourth embodiment are possible. The change in the arrangement of the dichroic film 23 and the polarizing film 24 on the joint surface of the color separation / synthesis unit 20 as in the present modification can also be applied to the first to third embodiments described above. .
[Fifth Embodiment]
In the present embodiment, the shape and the like of the prism constituting the color separation / combination unit 20 are further modified with respect to the first embodiment described above.

  FIG. 23 is a diagram illustrating the configuration of the two-plate projection device 500 in this embodiment, and shows the optical path of each color component when transmitted through a blue (B) specific wavelength polarization conversion element. The projection apparatus 500 is different only in that the shape of the prism used in the color separation / synthesis unit 20 is different from the arrangement of the quarter λ plate 14 and that a field lens 28 (field lens 29) is added. This is the same as the projection device 100. In addition, the projection apparatus 500 of this embodiment adds the field lens 28 (field lens 29) by changing the shape of the prism used in the color separation / synthesis unit 20 with respect to the projection apparatus 400 of the fourth embodiment. It has become the composition.

  The color separation / combination unit 20 is composed of two triangular prisms (prism 51, prism 52) having the same shape, and is joined on the long side surfaces of the triangle to form the color separation / combination unit 20 as a whole as shown in FIG. Has a quadrangular prism shape. The same is true in that an R-transmissive dichroic film 23 and a P-polarized transmissive polarizing film 24 are disposed on the joint surface of the prism, and that the dichroic film 23 is an S-polarized dichroic film. The quarter-λ plate 14 is disposed on the optical path between the color separation / combination unit 20 and the second spatial light modulator 16.

Hereinafter, the flow until the illumination light 3 incident on the color separation / synthesis unit 20 is projected as projection light 5 on a screen (not shown) will be described with reference to FIG.
The illumination light 3 incident on the color separation / combination unit 20 from the prism 51 in a state where only the blue (B) component is P-polarized light is incident on the R transmission type dichroic film 23 disposed on a part of the joint surface. The red (R) component of the illumination light 3 passes through the dichroic film 23, further passes through the prism 52, and enters the first spatial light modulator 15 at a predetermined angle. The other blue (B) and green (G) components are reflected by the dichroic film 23 and enter the second spatial light modulator 16 at a predetermined angle.

  Note that the dichroic film 23 is a dichroic film predominantly of S-polarized light, and the incident angle of the illumination light 3 to the dichroic film 23 is designed in advance so that a good characteristic can be obtained, as in the first embodiment. is there.

  The red (R) component that has been modulated by each pixel portion of the first spatial light modulator 15 and reflected in the normal direction by the amount of light required for each pixel is incident on the polarizing film 24. Since the polarizing film 24 is a P-polarized transmission type polarizing film, the red (R) component that is S-polarized light is reflected by the polarizing film 24 and emitted from the color separation / combination unit 20.

  On the other hand, green (G) and blue (B) components, which are modulated by the respective pixel portions of the second spatial light modulator 16 and are reflected in the normal direction by the amount of light necessary for each pixel, enter the polarizing film 24. At this time, the green (G) and blue (B) components reciprocate on the quarter λ plate 14 disposed on the optical path between the color separation / synthesis unit 20 and the second spatial light modulator 16. Therefore, the polarization direction is rotated by 90 degrees and converted from S-polarized light to P-polarized light and from P-polarized light to S-polarized light, respectively. Since the polarizing film 24 is a P-polarized transmission type polarizing film, the blue (B) component converted into S-polarized light is reflected by the polarizing film 24 and removed as unnecessary light 4, while green converted into P-polarized light. The component (G) passes through the polarizing film 24 and is emitted from the color separation / synthesis unit 20.

After that, the S-polarized red (R) component and the P-polarized green (G) component emitted from the color separation / combination unit 20 are projected as the projection light 5.
When only the green (G) component is incident on the color separation / synthesis unit 20 in the P-polarized state, the green (G) component is S-polarized light and the blue (B) component is P-polarized light. Therefore, the green (G) component that is S-polarized light is removed as unnecessary light 4, and the red (R) component of S-polarized light and the blue (B) component of P-polarized light are projected as projection light 5.

  Note that the number of reflections from the modulation by the spatial light modulator to the projection is one when the first spatial light modulator 15 modulates, but is zero when the second spatial light modulator 16 modulates. It has become times. For this reason, in order to prevent inversion of the image displayed by the projection light 5, the images generated by the first spatial light modulator 15 and the second spatial light modulator 16 are respectively illustrated in FIG. It is necessary to generate the video image 15a and the video direction 16a so as to be reversed in advance.

  As described above, the configuration of the present embodiment can also obtain the same effects as those of the first embodiment except that it is necessary to cope with the above-described video inversion. Further, since the field lens is added, the color separation / synthesis unit 20 and a projection lens (not shown) can be reduced in size, and aberrations (including chromatic aberration) can be corrected. In addition, there is an advantage that the directions of the illumination light 3 and the projection light 5 can be greatly changed. In addition, since only one type of prism is required for the color separation / synthesis unit 20 and a simple triangular prism shape, an effect of cost reduction can be obtained.

  Also in this embodiment, as in the case of the first embodiment, the polarization state of the illumination light 2 and the characteristics of the dichroic film 23 can be changed to various combinations. Further, as in the case of the first embodiment, a specific wavelength polarization conversion element or a 1 / 2λ plate 17 may be used instead of the 1 / 4λ plate 14 for modification.

Further, as in the second embodiment, the specific wavelength polarization conversion element may be arranged after exiting the color separation / synthesis unit 20 so as to align the polarization direction of the projection light 5.
In addition, the first spatial light modulator 15 and the second spatial light modulator 16 may be used in an oblique illumination oblique reflection configuration. Further, the configuration of the wheel-type wavelength selective polarization converter 13 is changed, the drum-type wavelength selective polarization converter 36, the slide-type wavelength selective polarization converter 37, the electronic color-specific polarization instead of the wheel-type wavelength selective polarization converter 13. Control means may be used.
[Sixth Embodiment]
In the present embodiment, the spatial light modulator is changed from a micromirror device to a reflective liquid crystal (LCOS) with respect to the first embodiment described above.

  Unlike the micromirror device, the reflective liquid crystal (LCOS) has a fixed reflection surface. For this reason, as shown in FIG. 24A, the illumination light 3 is incident in a diagonal direction at a predetermined angle with respect to the normal of the reflection surface, and the projection light 5 is emitted by regular reflection, and used in the oblique illumination oblique reflection configuration. There is a need to. Thereby, similarly to the case of the micromirror device, the optical path of the illumination light 3 and the optical path of the projection light 5 can be separated.

  In order to adjust the reflection direction, a field lens may be disposed in front of the reflective liquid crystal (LCOS) as illustrated in FIGS. 24B and 24C. As shown in FIG. 24C, the optical axis of the projection light 5 may be perpendicular to the reflective liquid crystal (LCOS).

  Note that the reflective liquid crystal (LCOS) has a characteristic of changing the polarization direction before and after modulation. For this reason, when the configuration used in the first embodiment is used, it is necessary to modify the polarizing film 24 so that the polarizing film 24 exhibits a characteristic opposite to that of the first embodiment.

As described above, even when the reflective liquid crystal (LCOS) is used instead of the micromirror device, the same effect as that of the first embodiment can be obtained by the configuration of the present embodiment.
Also in this embodiment, as in the case of the first embodiment, the polarization state of the illumination light 2 and the characteristics of the dichroic film 23 can be changed to various combinations. Further, as in the case of the first embodiment, a specific wavelength polarization conversion element or a 1 / 2λ plate 17 may be used instead of the 1 / 4λ plate 14 for modification.

Further, as in the second embodiment, the specific wavelength polarization conversion element may be arranged after exiting the color separation / synthesis unit 20 so as to align the polarization direction of the projection light 5.
Further, the configuration of the color separation / synthesis unit 20 may be the configuration of the fourth embodiment or the fifth embodiment.

In addition, the configuration of the wheel-type wavelength selective polarization converter 13 is changed, the drum-type wavelength-selective polarization converter 36, the slide-type wavelength-selective polarization converter 37, and the electronic color-specific polarization instead of the wheel-type wavelength-selective polarization converter 13. Control means may be used.
[Seventh Embodiment]
This embodiment differs from the first to sixth embodiments described above in that the illumination projection separation optical system is separated from the color separation / synthesis optical system and uses a TIR prism.

  FIG. 25 is a diagram illustrating the configuration of a two-plate type projector 700 according to this embodiment, and shows the optical path of each color component when transmitted through a blue (B) specific wavelength polarization conversion element. The projection device 700 includes a light source 11, a polarization conversion unit 12, a wheel-type wavelength selective polarization conversion unit 13, a first spatial light modulator 15, a second spatial light modulator 16, a color separation / synthesis unit 20, a TIR prism 30, The polarizing plate 27 includes a control circuit (not shown) that controls the spatial light modulator, and a projection lens (not shown). The color separation / combination unit 20 is a dichroic prism that includes two triangular prisms (prism 71 and prism 72) having the same shape, and an R reflection type dichroic film 23 is disposed on the joint surface of the prism. The dichroic film 23 is a P-polarized dichroic film that exhibits excellent characteristics with respect to P-polarized light. In the present embodiment, each of the first spatial light modulator 15 and the second spatial light modulator 16 uses a micromirror device.

  Hereinafter, the flow until the illumination light 1 emitted from the light source 11 is projected as projection light 5 onto a screen (not shown) will be described together with the operation of each component of the projection apparatus 700 with reference to FIG. .

  First, illumination light 1 including a plurality of wavelength components and a plurality of polarization directions emitted from a light source 11 such as a mercury lamp is converted into illumination light 2 having only a specific polarization direction by a polarization conversion unit 12. Here, the polarization conversion unit 12 acts to convert the illumination light 1 into P-polarized light.

  Next, the illumination light 2 converted into P-polarized light by the polarization converter 12 enters the wheel type wavelength selective polarization converter 13. In addition, about the structure of the wheel type | mold wavelength selection polarization conversion part 13, it is a structure illustrated by FIG. 2 similarly to 1st Embodiment. Since each specific wavelength polarization conversion element rotates the polarization plane of the specific wavelength by 90 degrees, in this embodiment, the polarization plane of the specific wavelength is converted from P-polarized light to S-polarized light. For this reason, the illumination light 3 that has passed through the wheel-type wavelength selective polarization converter 13 passes through the blue (B) specific wavelength polarization conversion element, and is only S-polarized (otherwise it is P-polarized) in the polarization direction of the blue (B) component. There are two states alternately with time, one state and a state in which only the polarization direction of the green (G) component is S-polarized light (otherwise it is P-polarized light). .

As will be described in detail later, the wavelength component converted into S-polarized light is removed by the polarizing plate 27 before reaching the screen (not shown) as unnecessary light 4.
First, the case of the illumination light 3 that passes through the blue (B) specific wavelength polarization conversion element and is in the S-polarized state only in the polarization direction of the blue (B) component will be described.

  The illumination light 3 transmitted through the wheel-type wavelength selective polarization conversion unit 13 is incident on the TIR prism 30 in a state where only the blue (B) component is S-polarized, that is, the component used as the projection light 5 is P-polarized. .

  FIG. 26 is a diagram for explaining the characteristics of the TIR prism disclosed in “Basic Theory of Optical Thin Films” published by Optronics. The reflectance characteristics with respect to the incident angle of the TIR prism are represented by the polarization direction (S-polarized light and P-polarized light). This is shown for each polarization). As shown in FIG. 26, the TIR prism has a characteristic that the reflectance gradually increases as the incident angle approaches the critical angle in the case of S-polarized light, while it reaches the critical angle in the case of P-polarized light. Has a characteristic of maintaining a low reflectivity and abruptly increasing the reflectivity when the incident angle reaches near the critical angle. For this reason, when the TIR prism is used as the illumination projection separation optical system, the P-polarized light exhibits better characteristics.

  In the present embodiment, in consideration of such characteristics of the TIR prism, in order to reduce the loss of light quantity in the TIR prism, the component used as the projection light 5 is incident as P-polarized light that the TIR prism 30 has good characteristics. ing.

  The illumination light 3 incident on the TIR prism 30 is incident on the boundary surface between the air and the prism 73 provided in the TIR prism 30 at an angle larger than the critical angle and is totally reflected. The totally reflected illumination light 3 exits from the TIR prism 30 and enters the color separation / combination unit 20.

  The illumination light 3 incident on the color separation / synthesis unit 20 from the prism 71 is incident on the R reflection type dichroic film 23 disposed on the bonding surface. Since the dichroic film 23 has an R reflection type characteristic, the red (R) component of the illumination light 3 is reflected by the dichroic film 23 and enters the first spatial light modulator 15 at a predetermined angle. The other blue (B) and green (G) components are transmitted through the dichroic film 23 and further transmitted through the prism 72 and enter the second spatial light modulator 16 at a predetermined angle.

  The red (R) component incident on the first spatial light modulator 15 is modulated by each pixel portion of the first spatial light modulator 15 and reflected in the normal direction by the amount of light necessary for each pixel. Thereafter, the light enters the color separation / synthesis unit 20 and is reflected by the dichroic film 23 again.

  Similarly, the blue (B) and green (G) components incident on the second spatial light modulator 16 are modulated by the respective pixel portions of the second spatial light modulator 16, and only a necessary light amount is calculated for each pixel. Reflects in the line direction. Thereafter, the light enters the color separation / synthesis unit 20 and passes through the dichroic film 23 again.

  In the case of the present embodiment, the dichroic film 23 acts on the light beam once before and after the modulation by the first spatial light modulator 15 (second spatial light modulator 16). Compared to the configuration, it is difficult to optimize the incident angle. However, by using the dichroic film 23 as a dichroic film that is predominantly P-polarized, good characteristics can be obtained in a relatively wide range with respect to the incident angle for the component used as the projection light 5 that is P-polarized. For this reason, also in this embodiment, the deterioration of the characteristics depending on the incident angle can be minimized.

  Each color component synthesized on the dichroic film 23 enters the TIR prism 30 at a critical angle or less and is transmitted. In this case, the components (red (R) and green (G) components) used as the projection light 5 are also P-polarized light that shows good characteristics of the TIR prism 30, and therefore when the light passes through the TIR prism 30. The amount of light loss that occurs can be minimized. Each of the color components transmitted through the TIR prism 30 is removed as unnecessary light 4 by the polarizing plate 27 that transmits only P-polarized light, and the remaining red (R) and green (G) components are projected light. Projected as 5.

  Thus, the illumination light 3 incident on the TIR prism 30 in the S-polarized state only in the polarization direction of the blue (B) component is incident on the polarizing plate 27 while maintaining the polarization state, and is P-polarized red (R). The green (G) component is projected onto the screen (not shown) as projection light 5.

  Even when only the polarization direction of the green (G) component is incident on the TIR prism 30 in the S-polarized state, it is incident on the polarizing plate 27 while maintaining the polarization state, and only the green (G) component of the S-polarized light is removed as unnecessary light 4. Thus, red (R) and blue (B) components of P-polarized light are projected as projection light 5 onto a screen (not shown).

  As described above, in the present embodiment, the illumination light 2 is alternately transmitted through the green (G) specific wavelength polarization conversion element and the blue (B) specific wavelength polarization conversion element, so that the red (R) component and the blue (B) component are transmitted. The synthesized light and the synthesized light of the red (R) component and the green (G) component are alternately projected to display a color image.

  As described above, in the present embodiment, the projection light generated in the TIR prism 30 by aligning the polarization direction (P-polarization) in which the TIR prism 30 exhibits good characteristics and the polarization direction of the component used as the projection light 5 are aligned. 5 light loss can be minimized.

  In the present embodiment, the dichroic film 23 acts multiple times. However, by using the dichroic film 23 exhibiting good characteristics in the polarization direction of the component used as the projection light 5, the dichroic film 23 is used. Therefore, it is possible to suppress deterioration of characteristics depending on the incident angle, maintain color separation accuracy, and project an image with good color reproducibility.

  Further, in the present embodiment, since the polarization direction of the projection light 5 is configured to have a specific direction, the contrast of the image can be improved by using the projection light 5 together with the polarization screen.

  In the present embodiment, as in the first embodiment, the first spatial light modulator 15 and the second spatial light modulator 16 may be used in an oblique illumination oblique reflection configuration. Further, the configuration of the wheel-type wavelength selective polarization converter 13 is changed, the drum-type wavelength selective polarization converter 36, the slide-type wavelength selective polarization converter 37, the electronic color-specific polarization instead of the wheel-type wavelength selective polarization converter 13. Control means may be used.

In addition, a field lens may be used as in the third embodiment.
[First Modification of Seventh Embodiment]
The first modified example of the seventh embodiment is a case where the polarization directions showing good characteristics of the TIR prism 30 and the dichroic film 23 are different, and a 1 / 2λ between the TIR prism 30 and the color separation / synthesis unit 20. A plate 75 is added.

  FIG. 27 is a diagram illustrating a part of the configuration of the two-plate type projector 700 in the present modification, and shows the optical paths of the respective color components when transmitted through the blue (B) specific wavelength polarization conversion element. Differences in configuration from the seventh embodiment are the following two points.

  The first difference is that the dichroic film 23 is changed from an R reflection type having P-polarized dominant characteristics to an R transmission type having S-polarized dominant characteristics. As a result, the TIR prism 30 and the dichroic film 23 have different polarization directions indicating P polarization and S polarization, respectively.

  The second difference is that a ½λ plate 75 is added between the TIR prism 30 and the color separation / combination unit 20. This is a measure for adjusting the difference in polarization direction, which shows good characteristics between the TIR prism 30 and the dichroic film 23 caused by the first difference. As a result, the polarization direction is converted on the optical path between the color separation / synthesis unit 20 including the dichroic film 23 and the TIR prism 30, and the TIR prism 30 is P-polarized light that exhibits good characteristics. The dichroic film 23 can be incident on the dichroic film 23 with S-polarized light having good characteristics.

  As described above, in the present modification, even when the TIR prism 30 and the dichroic film 23 exhibit good characteristics with respect to different polarization directions, the same effect as in the seventh embodiment can be obtained.

Also in this modification, the same modification as in the seventh embodiment is possible.
Needless to say, the present invention is not limited to the configuration exemplified in the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is the figure which illustrated the structure of the projection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which illustrates the structure of the wheel-type wavelength selection polarization conversion part contained in the projection apparatus which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 1st Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 1st Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 1st Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 1st Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 1st Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 1st Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 1st Embodiment of this invention. It is a figure which shows the mode of the vertical reflection by the spatial light modulator which concerns on the 1st Embodiment of this invention. It is a figure which shows the mode of the diagonal reflection by the spatial light modulator which concerns on the 1st Embodiment of this invention. It is a figure which illustrates the modification of a structure of the wheel-type wavelength selection polarization conversion part contained in the projection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which illustrates the other modification of a structure of the wheel type wavelength selection polarization conversion part contained in the projection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which illustrates further another modification of the composition of the wheel type wavelength selection polarization conversion part contained in the projection device concerning a 1st embodiment of the present invention. It is a figure which illustrates further another modification of the composition of the wheel type wavelength selection polarization conversion part contained in the projection device concerning a 1st embodiment of the present invention. It is a figure which illustrates further another modification of the composition of the wheel type wavelength selection polarization conversion part contained in the projection device concerning a 1st embodiment of the present invention. It is a figure which illustrates the structure of the drum type | mold wavelength selective polarization conversion part contained in the projector which concerns on the 1st Embodiment of this invention. It is a figure which illustrates the structure of the slide-type slide-type wavelength selection polarization conversion part contained in the projector which concerns on the 1st Embodiment of this invention. It is the figure which illustrated a part of structure of the projection apparatus which concerns on the 1st modification of the 1st Embodiment of this invention. It is the figure which illustrated a part of structure of the projection apparatus which concerns on the 2nd modification of the 1st Embodiment of this invention. It is the figure which illustrated a part of structure of the projection apparatus which concerns on the 3rd modification of the 1st Embodiment of this invention. It is the figure which illustrated a part of structure of the projection apparatus which concerns on the 4th modification of the 1st Embodiment of this invention. It is the figure which illustrated the structure of the projection apparatus which concerns on the 2nd Embodiment of this invention. It is the figure which illustrated a part of structure of the projection apparatus which concerns on the 1st modification of the 2nd Embodiment of this invention. It is the figure which illustrated the structure of the projection apparatus which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the entrance ray position of the chief ray and projection lens in the 3rd Embodiment of this invention. It is a figure for demonstrating the entrance ray position of the chief ray and projection lens in the 3rd Embodiment of this invention. It is the figure which illustrated the structure of the projection apparatus which concerns on the 4th Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 4th Embodiment of this invention. It is a figure for demonstrating the optical path of each color component in the 4th Embodiment of this invention. It is the figure which changed the combination of the polarization state of the projector which concerns on the 4th Embodiment of this invention, and the characteristic of a dichroic film | membrane. It is the figure which changed the combination of the polarization state of the projector which concerns on the 4th Embodiment of this invention, and the characteristic of a dichroic film | membrane. It is the figure which changed the combination of the polarization state of the projector which concerns on the 4th Embodiment of this invention, and the characteristic of a dichroic film | membrane. It is a figure for demonstrating the entrance ray position of the chief ray and projection lens in the 4th Embodiment of this invention. It is a figure for demonstrating the entrance ray position of the chief ray and projection lens in the 4th Embodiment of this invention. It is a figure explaining the optical path from the incidence | injection to the emission to the color separation synthetic | combination part contained in the projection apparatus which concerns on the 1st modification of the 4th Embodiment of this invention. It is a figure explaining arrangement | positioning of the dichroic film | membrane and polarizing film in the joint surface of the color separation synthetic | combination part of the projection apparatus which concerns on the 2nd modification of the 4th Embodiment of this invention. It is a figure explaining arrangement | positioning of the dichroic film | membrane and polarizing film in the joint surface of the color separation synthetic | combination part of the projection apparatus which concerns on the 2nd modification of the 4th Embodiment of this invention. It is a figure explaining arrangement | positioning of the dichroic film | membrane and polarizing film in the joint surface of the color separation synthetic | combination part of the projection apparatus which concerns on the 2nd modification of the 4th Embodiment of this invention. It is a figure explaining other arrangement | positioning of the dichroic film | membrane and polarizing film in the joint surface of the color separation synthetic | combination part of the projection apparatus which concerns on the 2nd modification of the 4th Embodiment of this invention. It is the figure which illustrated the structure of the projection apparatus which concerns on the 5th Embodiment of this invention. It is a figure which illustrates the reflective direction in the spatial light modulator contained in the projection apparatus which concerns on the 6th Embodiment of this invention. It is a figure which illustrates the reflection direction at the time of arrange | positioning the field lens in front of the spatial light modulator contained in the projection apparatus which concerns on the 6th Embodiment of this invention. It is a figure which illustrates the reflection direction at the time of arrange | positioning the field lens in front of the spatial light modulator contained in the projection apparatus which concerns on the 6th Embodiment of this invention. It is the figure which illustrated the structure of the projection apparatus which concerns on the 7th Embodiment of this invention. It is a figure explaining the characteristic of a TIR prism. It is the figure which illustrated a part of structure of the projection apparatus which concerns on the 1st modification of the 7th Embodiment of this invention. It is a block diagram of the 3 plate type | mold projection apparatus of a prior art. It is a block diagram of the 2 plate type projection apparatus of a prior art. It is a top view which shows the structure of the 3 plate type | mold projection apparatus of a prior art. It is a side view which shows the structure of the 3 plate type | mold projection apparatus of a prior art. It is a block diagram of the 3 plate type | mold projection apparatus of a prior art. It is a figure for demonstrating the light quantity loss which arises in a dichroic film | membrane. It is a figure which illustrates the characteristic with respect to P polarization | polarized-light of an R transmission type dichroic film | membrane. It is a figure which illustrates the characteristic with respect to S polarization | polarized-light of an R transmission type dichroic film | membrane. It is a figure which illustrates the characteristic with respect to P polarization | polarized-light of an R reflection type dichroic film. It is a figure which illustrates the characteristic with respect to S polarization of an R reflection type dichroic film.

Explanation of symbols

1, 2, 3 ... Illumination light 4 ... Unnecessary light 5 ... Projection light 6 ... Main ray 11・ ・ ・ ・ ・ ・ ・ ・ ・ Light source 12 ・ ・ ・ ・ ・ ・ ・ ・ Polarization converter 13, 31, 32, 33, 34, 35 ・ ・ ・ Wheel type wavelength selective polarization converter 14 ・ ・ ・ ・ ・ ・ ・ ・1 / 4λ plate 15... First spatial light modulator 16... Second spatial light modulator 17, 75. ..... color separation / synthesis unit 21, 22, 41, 42, 51, 52, 71, 72, 73, 74 ... prism 23, 26 ... dichroic film 24 ... ... Polarizing film 25 ... Red specific wavelength polarization conversion element 27 ... Polarizing plates 28, 29 ... Field lens 30 ... TIR prism 36... Drum type wavelength selective polarization converter 37... Slide type wavelength selective polarization converter 100, 200, 300, 400, 500, 700.

Claims (35)

A plurality of reflective spatial light modulators;
The first dichroic film and the reflection type spatial light modulator with little deterioration of color separation characteristics depending on an incident angle with respect to a specific polarization direction for color separation of illumination light from the outside and guiding it to the reflection type spatial light modulator A color separation / synthesis unit including color synthesis means for synthesizing modulated light according to
An optical system that projects only the wavelength component incident on the first dichroic film in the specific polarization direction in the illumination light. The optical system according to claim 1.
The plurality of reflective spatial light modulators are two reflective spatial light modulators;
The color composition means is a polarizing film,
The color separation / synthesis unit includes two prisms in which the first dichroic film and the polarizing film are disposed on a bonding surface,
The optical system further includes a wavelength plate between one of the two reflective spatial light modulators and the color separation / synthesis unit. The optical system according to claim 2,
The wavelength plate is a λλ plate or a specific wavelength polarization conversion element that acts as a λλ plate only for a wavelength component incident on the reflection type spatial light modulator, and an incident optical path of the reflection type spatial light modulator An optical system characterized by being disposed across both of the reflected light paths. The optical system according to claim 2,
The wavelength plate is a 1 / 2λ plate or a specific wavelength polarization conversion element that acts as a 1 / 2λ plate only on a wavelength component incident on the reflective spatial light modulator, and an incident optical path of the reflective spatial light modulator or An optical system, wherein the optical system is disposed so as to intersect only one of the reflected light paths. In the optical system according to any one of claims 2 to 4,
The optical system further includes a specific wavelength polarization conversion element on an optical path of the combined light emitted from the color separation / synthesis unit. The optical system according to any one of claims 2 to 5,
Further, a projection lens disposed on the optical path of the combined light emitted from the color separation / combination unit, and one each disposed between each of the two reflective spatial light modulators and the color separation / combination unit. A field lens, and
The optical system, wherein the projection lens and the field lens act as a substantially telecentric optical system on the reflective spatial light modulator side. The optical system according to claim 6.
An optical system, wherein an entrance pupil position of the projection lens is near the polarizing film. The optical system according to claim 6.
An optical system, wherein an entrance pupil position of the projection lens is closer to the projection lens than the color separation / synthesis unit. The optical system according to any one of claims 2 to 8,
The two prisms have different shapes, respectively. The optical system according to any one of claims 2 to 8,
Each of the two prisms is a triangular prism having the same shape,
2. The optical system according to claim 1, wherein the color separation / synthesis unit has a quadrangular prism shape. The optical system according to any one of claims 2 to 8,
Each of the two prisms is a triangular prism having the same shape,
2. The optical system according to claim 1, wherein the color separation / synthesis unit has a triangular prism shape. The optical system according to any one of claims 2 to 11,
The reflective spatial light modulator is a micromirror device that modulates incident light by controlling the inclination of a plurality of micromirrors,
The micromirror device reflects incident light incident from an oblique direction in an oblique direction with respect to the normal to the normal of the reflection surface of the micromirror in a state before the micromirror is controlled. An optical system characterized by The optical system according to any one of claims 2 to 11,
The reflective spatial light modulator is a micromirror device that modulates incident light by controlling the inclination of a plurality of micromirrors,
The micromirror device reflects incident light incident in an oblique direction with respect to a normal line of a reflection surface of the micromirror in a state before the micromirror is controlled, in the normal line direction. Optical system. The optical system according to any one of claims 2 to 11,
The reflective spatial light modulator is a reflective liquid crystal (LCOS),
The optical system characterized in that the reflective liquid crystal reflects incident light incident from an oblique direction with respect to a normal line of a reflective surface of the reflective liquid crystal in an oblique direction with respect to the normal line. The optical system according to any one of claims 2 to 14,
The specific polarization direction is P-polarized light,
The optical system, wherein the first dichroic film reflects a wavelength component corresponding to red and transmits wavelength components corresponding to green and blue. The optical system according to any one of claims 2 to 14,
The specific polarization direction is S-polarized light,
The optical system, wherein the first dichroic film transmits a wavelength component corresponding to red and reflects wavelength components corresponding to green and blue. The optical system according to claim 1.
The plurality of reflective spatial light modulators are two reflective spatial light modulators;
The color synthesizing means is a second dichroic film with little deterioration of color separation characteristics depending on an incident angle with respect to the specific polarization direction,
The color separation / synthesis unit is composed of two prisms in which the first dichroic film and the second dichroic film are arranged on a joint surface,
The optical system further includes a polarizing plate disposed on an optical path of the combined light emitted from the color separation / synthesis unit. The optical system according to claim 17,
The specific polarization direction is P-polarized light,
The polarizing plate transmits only P-polarized light,
The optical system, wherein the first dichroic film and the second dichroic film reflect a wavelength component corresponding to red and transmit wavelength components corresponding to green and blue. The optical system according to claim 17,
The specific polarization direction is S-polarized light,
The polarizing plate transmits only S-polarized light,
The optical system, wherein the first dichroic film and the second dichroic film transmit a wavelength component corresponding to red and reflect a wavelength component corresponding to green and blue. A TIR prism that directs illumination light;
A plurality of micromirror devices that modulate different wavelength components of the illumination light;
A dichroic in which the illumination light is separated by a dichroic film with little deterioration in color separation characteristics depending on an incident angle with respect to a specific polarization direction and guided to the micromirror device, and modulated light by the micromirror device is synthesized by the dichroic film Prism,
A polarizing plate that transmits only P-polarized light among the combined light synthesized by the dichroic prism,
An optical system that projects only a component of the illumination light incident on the dichroic film in the specific polarization direction. The optical system according to claim 20,
The optical system characterized in that the specific polarization direction is P-polarized light. The optical system according to claim 20,
The specific polarization direction is S-polarized light,
The optical system further comprises a ½λ plate between the TIR prism and the dichroic prism. The optical system according to claim 21,
The optical system characterized in that the dichroic film reflects a wavelength component corresponding to red and transmits wavelength components corresponding to green and blue. The optical system according to claim 22,
The optical system characterized in that the dichroic film transmits a wavelength component corresponding to red and reflects wavelength components corresponding to green and blue. A light source that emits illumination light including a plurality of wavelength components;
A wavelength-selective polarization converter that converts the polarization direction of the illumination light in a wavelength-selective manner while switching the wavelength component that converts the polarization direction over time;
An optical system according to claim 1 or 20,
Of the illumination light, a projection apparatus that projects a wavelength component whose polarization direction is not converted by the wavelength selective polarization conversion unit. The projection device according to claim 25, wherein
The plurality of wavelength components are wavelength components corresponding to red, green, and blue,
The wavelength selective polarization converter converts the polarization direction of the wavelength component corresponding to the green color of the illumination light and the polarization direction of the wavelength component corresponding to the blue color alternately. The projection device according to claim 25, wherein
The wavelength selective polarization converter converts the polarization direction of the illumination light from P-polarized light to S-polarized light in a wavelength-selective manner while switching wavelength components for changing the polarization direction over time. The projection device according to claim 25, wherein
The plurality of wavelength components are wavelength components corresponding to red, green, and blue,
The wavelength selective polarization converter converts the polarization direction of the wavelength component corresponding to green and the polarization direction of the wavelength component corresponding to blue of the illumination light alternately from P-polarized light to S-polarized light. . The projection device according to claim 26 or claim 28,
The projection apparatus characterized in that the time for projecting the wavelength component corresponding to the green is equal to or longer than the time for projecting the wavelength component corresponding to the blue. The projection device according to claim 29, wherein
The ratio of the time for projecting the wavelength component corresponding to green to the time for projecting the wavelength component corresponding to blue is 0.7: 0.3 to 0.5: 0.5 apparatus. The projection device according to any one of claims 25 to 30, wherein
The projection apparatus further includes a polarization conversion unit that converts the illumination light emitted from the light source into a specific polarization direction between the light source and the wavelength selective polarization conversion unit. The projection apparatus according to any one of claims 25 to 31,
The wavelength selective polarization conversion unit includes a plurality of specific wavelength polarization conversion elements arranged radially on the same plane and having a circular shape as a whole,
The plurality of the specific wavelength polarization conversion elements rotate around a rotation axis that is perpendicular to the plane and passes through the center of the circle. The projection apparatus according to any one of claims 25 to 31,
The wavelength selective polarization conversion unit forms a cylinder as a whole, and includes a plurality of specific wavelength polarization conversion elements disposed on the surface of the cylinder, and reflection means disposed inside the cylinder,
The plurality of the specific wavelength polarization conversion elements rotate around a rotation axis passing through a center of the cylinder. The projection apparatus according to any one of claims 25 to 31,
The wavelength selective polarization conversion unit includes a plurality of specific wavelength polarization conversion elements arranged in a certain direction,
The plurality of specific wavelength polarization conversion elements slide along the certain direction. The projection apparatus according to any one of claims 25 to 31,
The projection apparatus, wherein the wavelength selective polarization conversion unit is an electronic color-specific polarization control unit that switches a wavelength component for converting a polarization direction by electrical control.