JP2006126573A - Color decomposition/composition optical system and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color decomposition/composition optical system which is prevented from deteriorating in optical characteristic by making luminous flux of a polarization beam splitter as to, specially, blue component light incident from the side of an adhesive layer, and an image display device. <P>SOLUTION: The blue component light B emitted by a first polarization beam splitter 2 is made incident on a third polarization beam splitter 7 as a third polarized light separating element. In the third polarization beam splitter 7, the incident blue component light B is transmitted through the adhesive layer 7b to become S-polarized light to a polarized light separating film 7a slanted at 45° to the optical path of the incident light. This blue component light B is reflected by the polarized light separating film 7a and emitted from the third polarization beam splitter 7 to impinge on a reflection type spatial optical modulating element 8 as a third spatial optical modulating element. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color separation / combination optical system that splits an incident light beam into three primary colors, recombines and emits the same, and an image display device configured using such a color separation / combination optical system.

  Conventionally, an image display apparatus using a reflective spatial light modulator has been proposed. In such an image display device, as described in Patent Document 1 and Patent Document 2, a color separation / synthesis optical system configured using a polarization beam splitter is used. This color separation / synthesis optical system separates an incident light beam from a light source into three primary colors, illuminates a reflective spatial light modulation element for each color with these three primary color lights, and reflects the reflected light beam from these reflective spatial light modulation elements. It is an optical system that combines again and emits it toward the imaging system.

  FIG. 5 is a plan view showing a configuration of a conventional color separation / synthesis optical system used in the image display apparatus.

  In this color separation / synthesis optical system, a light beam emitted from a light source (not shown) is made into a substantially parallel light beam, and is made into linearly polarized light and incident. This incident light beam includes red component light R, green component light G, and blue component light B, the component light of each color is linearly polarized, and the polarization plane of each color component light is in the same direction. Yes.

  This incident light beam is incident on the first laminated phase difference filter 101. This laminated phase difference filter 101 is an optical element configured by laminating phase difference plates, and is a filter that rotates the direction of the polarization plane of only a specific wavelength band by 90 °. In the light flux that has passed through the first laminated phase difference filter 101, the polarization plane of the green component light G is orthogonal to the polarization planes of the red component light R and the blue component light B.

  The light beam that has passed through the first laminated phase difference filter 101 is incident on the first polarization beam splitter 102. In the first polarization beam splitter 102, the green component light G is P-polarized, the red component light R, and the blue component light B are S-polarized with respect to the polarization separation film 102a. Accordingly, in the first polarization beam splitter 102, the red component light R and the blue component light B are reflected by the polarization separation film 102a, and the green component light G is transmitted through the polarization separation film 102a.

  The red component light R and the blue component light B emitted from the first polarization beam splitter 102 are incident on the second stacked phase difference filter 103. The second laminated phase difference filter 103 transmits the red component light R and the blue component light B with the polarization plane of the red component light R orthogonal to the polarization plane of the blue component light B.

  The light beam that has passed through the second stacked phase difference filter 103 is incident on the second polarization beam splitter 104. In the second polarization beam splitter 104, the red component light R is P-polarized light and the blue component light B is S-polarized light with respect to the polarization separation film 104a. The red component light R is transmitted through the polarization separation film 104 a, is emitted from the second polarization beam splitter 104, and enters the red reflective spatial light modulator 105. Further, the blue component light B is reflected by the polarization separation film 104 a, is emitted from the second polarization beam splitter 104, and enters the blue reflective spatial light modulation element 106.

  The red reflective spatial light modulator 105 and the blue reflective spatial light modulator 106 are so-called reflective liquid crystal display devices, which respectively modulate the polarization of incident light according to the red and blue components of the display image. Reflect.

  The first modulated light modulated and reflected by the red reflective spatial light modulator 105 is incident on the second polarization beam splitter 104 again. Since the first modulated light is S-polarized with respect to the polarization separation film 104a, the first modulated light is reflected by the polarization separation film 104a and is transmitted from the second polarization beam splitter 104 to the first polarization beam splitter 102. The light is emitted in a direction different from the returning direction.

  The second modulated light modulated and reflected by the blue reflective spatial light modulator 106 is incident on the second polarization beam splitter 104 again. Since the second modulated light is P-polarized with respect to the polarization separation film 104a, the second modulated light is transmitted through the polarization separation film 104a and is transmitted from the second polarization beam splitter 104 to the first polarization beam splitter 102. The light is emitted in a direction different from the direction returning to.

  On the other hand, the green component light G emitted from the first polarization beam splitter 102 is incident on the third polarization beam splitter 107. In the third polarization beam splitter 107, the green component light G is P-polarized with respect to the polarization separation film 107a. The green component light G passes through the polarization separation film 107a, is emitted from the third polarization beam splitter 107, and is incident on the green reflective spatial light modulator 108. The green reflective spatial light modulator 108 is a so-called reflective liquid crystal display device, and reflects incident light by polarization-modulating it according to the green component of the display image.

  The third modulated light modulated and reflected by the green reflective spatial light modulator 108 is incident on the third polarizing beam splitter 107 again. Since the third modulated light is S-polarized light with respect to the polarization separation film 107 a, it is reflected by the polarization separation film 107 a and is transmitted from the third polarization beam splitter 107 to the first polarization beam splitter 102. The light is emitted in a direction different from the direction returning to.

  The first and second modulated lights emitted from the second polarization beam splitter 104 are incident on the third stacked phase difference filter 109. The third stacked phase difference filter 109 rotates the polarization plane of the first modulated light by 90 °, transmits the first and second modulated lights, and enters the fourth polarizing beam splitter 110. At this time, the polarization planes of the first and second modulated lights are in the same direction.

  Further, the third modulated light emitted from the third polarizing beam splitter 107 is incident on the fourth polarizing beam splitter 110.

  In the fourth polarization beam splitter 110, the first and second modulated lights are P-polarized and the third modulated light is S-polarized with respect to the polarization separation film 110a. The first and second modulated lights pass through the polarization separation film 110 a and are emitted from the fourth polarization beam splitter 110. The third modulated light is reflected by the polarization separation film 110 a and is emitted from the fourth polarization beam splitter 110. In this way, the first and second modulated light and the third modulated light are combined.

  The first to third modulated lights emitted from the fourth polarization beam splitter 110 are incident on the fourth stacked phase difference filter 111. The fourth laminated phase difference filter 111 rotates the polarization plane of the third modulated light by 90 ° and transmits the first to third modulated lights. The first to third modulated lights that have passed through the fourth laminated phase difference filter 111 have the same polarization plane.

The first to third modulated light beams that have passed through the fourth stacked phase difference filter 111 are transmitted through the polarizing plate 112, thereby removing unnecessary light having different polarization plane directions and entering a projection optical system (not shown). . The projection optical system projects the first to third modulated light onto the screen and displays an image.
JP 2002-287094 A JP 2000-284228 A

  As shown in FIG. 6, the polarization beam splitter used in the color separation / synthesis optical system as described above includes a first triangular prism 1201 having a polarization separation film 120a formed by vapor deposition on one surface, and the first triangular prism 1201. The triangular prism 1201 is formed in a cubic shape from the polarization separating film 120a and the second triangular prism 1202 bonded via the adhesive layer 120b to the surface on which the polarization separating film 120a is formed.

  Accordingly, when such a polarizing beam splitter is arranged in the color separation / synthesis optical system, the light beam that has passed through the polarization separation film 120a passes through the adhesive layer 120b as the path of the light beam passing through the adhesive layer 120b, and the adhesive layer 120b. Some of the transmitted light passes through the polarization separation film 120a.

  By the way, in the polarizing beam splitter in which the first triangular prism 1201 and the second triangular prism 1202 are bonded via an adhesive layer to form a cube shape, the transmission order of the light fluxes between the adhesive layer and the polarization separation film. Found that the optical properties differ.

  Therefore, the present invention relates to a color separation / synthesis optical system used in an image display device having a reflective spatial light modulation element, and the transmission of a light beam between an adhesive layer and a polarization separation film in a polarization separation element such as a polarization beam splitter. It is an object of the present invention to provide a color separation / synthesis optical system in which the order is prescribed to prevent deterioration, and to provide an image display device configured using such a color separation / synthesis optical system.

In order to solve the above-mentioned problems, the present invention comprises means described in the following 1) to 2).
That is,
1) First wavelength selective polarization in which a linearly polarized white light beam is incident and the polarization planes of the red component light and the green component light of the incident beam are orthogonal to the polarization plane of the blue component light Conversion means;
A red light component and a green light component are obtained by transmitting a P-polarized light component and reflecting an S-polarized light component with respect to the polarized light-separating film, and having a polarized light separating film on which the light beam having passed through the first wavelength-selective polarization converting means is incident. A first polarization separation element for branching an optical path between the light and the blue component light;
Red component light and green component light are incident from the first polarization separation element, and the polarization plane of the first color component light and the polarization plane of the second color component light out of the red component light and the green component light. Second wavelength-selective polarization conversion means that are orthogonal to each other;
The first and second color component lights are incident from the second wavelength selective polarization conversion means, the first color component light is incident on the first spatial light modulator, and the second color component light is A second polarization separation element that is incident on the second spatial light modulation element;
A third polarization separation element that receives blue component light from the first polarization separation element and makes the blue component light incident on a third spatial light modulation element;
The modulated light of the red component light and the green component light that has passed through the first and second spatial light modulation elements and the modulated light of the blue component light that has passed through the third spatial light modulation element are incident, A polarization combining element that combines and emits; and
With
At least the third polarization separation element includes a first prism on which a polarization separation film is formed, and a surface of the first prism on which the polarization separation film is formed via the polarization separation film and an adhesive layer. A polarizing beam splitter comprising a second prism bonded together,
The blue component light traveling toward the third spatial light modulator is incident on the second prism, passes through the adhesive layer, is reflected by the polarization separation film, and is emitted from the second prism. A color separation / synthesis optical system.
2) The color separation / synthesis optical system according to 1),
Light source means for making a light beam including at least a red component light, a green component light, and a blue component light in a linearly polarized state incident on the color separation / synthesis optical system;
An imaging optical system that forms an image of a light beam emitted from the polarization combining element of the color separation / synthesis optical system;
An image display device comprising:

  In the color separation / synthesis optical system according to the present invention, in particular, the polarization separation film and the adhesive layer are arranged so that the light beam of the polarization beam splitter related to the blue component light is incident from the adhesive layer side, thereby preventing deterioration of contrast. Therefore, it is possible to provide a color separation / synthesis optical system capable of preventing deterioration of optical characteristics.

  In the image display apparatus according to the present invention, a color separation / synthesis optical system in which deterioration of optical characteristics is prevented is provided, and an image display apparatus configured using such a color separation / synthesis optical system is provided. Can be provided.

  The best mode for carrying out the invention of the color separation / synthesis optical system and the image display apparatus according to the present invention will be described below with reference to preferred embodiments.

  FIG. 1 is a schematic plan view illustrating a configuration of an image display device applied to the first embodiment.

  In this color separation / synthesis optical system, as shown in FIG. 1, a light beam is incident on a first laminated phase difference filter 1 serving as a first wavelength-selective polarization conversion unit by an illumination optical system 13 serving as a light source unit. The

  The illumination optical system 13 includes a light source 14 and a concave mirror 15 that collects a light beam emitted from the light source 14. The light emitted from the light source 14 is reflected by the concave mirror 15, passes through the heat ray filter 16, passes through the condenser lens 17 and the polarization conversion element 18, and is emitted from the illumination optical system 13.

  The light beam emitted from the illumination optical system 13 is substantially a parallel light beam and linearly polarized light. The light beam emitted from the illumination optical system 13 includes red component light R, blue component light B, and green component light G. Each of these color component lights R, B, and G is linearly polarized, and the planes of polarization are in the same direction. In this embodiment, the polarization plane of each color component light of the incident light is in a direction parallel to the paper surface of FIG.

  The first laminated phase difference filter 1 to which the light beam from the illumination optical system 13 is incident is an optical element formed by laminating phase difference plates, and the direction of the polarization plane of only a specific wavelength band is 90 °. It is a filter to rotate. As such a laminated phase difference filter, for example, “Color Select” manufactured by Color Link can be used.

  In the light flux that has passed through the first laminated phase difference filter 1, the red component light R, the blue component light B, and the green component light G are each linearly polarized light, and the direction of the polarization plane of only the blue component light B is 90. Rotated, the polarization plane of the blue component light B is orthogonal to the polarization planes of the red component light R and the green component light G.

  The light beam that has passed through the first laminated phase difference filter 1 is incident on a first polarization beam splitter 2 that serves as a first polarization separation element. In the first polarization beam splitter 2, the red component light R and the green component light G are P-polarized and blue component light B with respect to the polarization separation film 2 a inclined at 45 ° with respect to the optical path of the incident light. Is S-polarized light. Therefore, in the first polarization beam splitter 2, the red component light R and the green component light G are transmitted through the polarization separation film 2a, and the blue component light B is reflected by the polarization separation film 2a. The optical path of the green component light G and the optical path of the blue component light B are branched according to the polarization plane direction.

  The first polarizing beam splitter 2 includes a first triangular prism 21 having a polarization separation film 2a formed on one surface by vapor deposition or the like, and a surface on which the polarization separation film 2a of the first triangular prism 21 is formed. In contrast to this, the polarization separating film 2a and the second triangular prism 22 bonded through the adhesive layer 2b are formed in a cubic shape.

  The light beam that has passed through the first laminated phase difference filter 1 is incident on the first polarizing beam splitter 2 from the first triangular prism 21 side. Accordingly, the blue component light B reflected by the polarization separation film 2a is reflected by the polarization separation film 2a without passing through the adhesive layer 2b joining the triangular prisms, and is emitted from the first triangular prism 21. Is done.

  The red component light R and the green component light G emitted from the first polarization beam splitter 2 are incident on the second laminated phase difference filter 3 serving as the second wavelength selective polarization conversion means. The second laminated phase difference filter 3 rotates the polarization plane of only the green component light G by 90 °, and the green component light G is in a state in which the polarization plane of the green component light G is orthogonal to the polarization plane of the red component light R. The component light G and the red component light R are transmitted.

  The light beam that has passed through the second laminated phase difference filter 3 is incident on a second polarization beam splitter 4 that serves as a second polarization separation element. In the second polarization beam splitter 4, the red component light R is P-polarized light and the green component light G is S-polarized light with respect to the polarization separation film 4 a inclined at 45 ° with respect to the optical path of the incident light. ing. The red component light R is transmitted through the polarization separation film 4a and the adhesive 4b layer, is emitted from the second polarization beam splitter 4, and is applied to the red reflective spatial light modulator 5 which is the first spatial light modulator. Incident. Further, the green component light G is reflected by the polarization separation film 4a, is emitted from the second polarization beam splitter 4, and enters the green reflective spatial light modulation element 6 which is the second spatial light modulation element.

  Similarly to the first polarizing beam splitter 2, the second polarizing beam splitter 4 also includes a first triangular prism 41 having a polarizing separation film 4a formed on one surface by vapor deposition or the like, and the first triangular prism. The second triangular prism 42 adhered to the surface on which the polarization separation film 4a 41 is formed via the polarization separation film 4a and the adhesive layer 4b is formed in a cubic shape.

  The light beam that has passed through the second laminated phase difference filter 3 is incident on the second polarizing beam splitter 2 from the first triangular prism 41 side. Therefore, the green component light G reflected by the polarization separation film 4a is reflected by the polarization separation film 4a without passing through the adhesive layer 4b joining the triangular prisms, and is emitted from the first triangular prism 41. Is done.

  The red reflective spatial light modulator 5 and the green reflective spatial light modulator 6 are so-called reflective liquid crystal display devices, which respectively modulate the polarization of incident light according to the red and green components of the display image. Reflect. Information on the display image is supplied from the outside to the red reflective spatial light modulator 5 and the green reflective spatial light modulator 6.

  The first modulated light modulated and reflected by the red reflective spatial light modulator 5 is incident on the second polarization beam splitter 4 again. The first modulated light is S-polarized with respect to the polarization separation film 4a when the red reflective spatial light modulation element 5 displays white, and is reflected by the polarization separation film 4a. The light is emitted from the second polarizing beam splitter 4 in a direction different from the direction returning to the first polarizing beam splitter 2.

  The second modulated light modulated and reflected by the green reflective spatial light modulator 6 is incident on the second polarization beam splitter 4 again. Since the second modulated light is P-polarized with respect to the polarization separation film 4a when the green reflective spatial light modulation element 6 is displaying white, the polarization separation film 4a and the adhesive layer 4b. And is emitted from the second polarization beam splitter 4 in a direction different from the direction returning to the first polarization beam splitter 2.

  On the other hand, the blue component light B emitted from the first polarization beam splitter 2 is incident on a third polarization beam splitter 7 serving as a third polarization separation element. A blue light transmission filter 7 c may be disposed between the first polarization beam splitter 2 and the third polarization beam splitter 7. In the third polarizing beam splitter 7, after the incident blue component light B is transmitted through the adhesive layer 7b, the polarization separating film 7a inclined at 45 ° with respect to the optical path of the incident light, The blue component light B is S-polarized light. The blue component light B is reflected by the polarization separation film 7a, is emitted from the third polarization beam splitter 7, and is incident on the blue reflective spatial light modulator 8 which is the third spatial light modulator. The blue reflective spatial light modulator 8 is a so-called reflective liquid crystal display device, and reflects incident light by polarization-modulating the incident light according to the green component of the display image. Information of the display image is supplied to the blue reflective spatial light modulator 8 from the outside.

  Similarly to the first polarizing beam splitter 2, the third polarizing beam splitter 7 also includes a second triangular prism 72 having a polarizing separation film 7a formed on one surface by vapor deposition or the like, and the second triangular prism. The first triangular prism 71 adhered to the surface on which the polarization separation film 7a 72 is formed via the polarization separation film 7a and the adhesive layer 7b is formed in a cubic shape. The blue component light B emitted from the first polarization beam splitter 2 is incident on the third polarization beam splitter 7 from the first triangular prism 71 side.

  The third modulated light modulated and reflected by the blue reflective spatial light modulator 8 is incident on the third polarization beam splitter 7 again. Since the third modulated light is P-polarized with respect to the polarization separation film 7a when the blue reflective spatial light modulation element 8 displays white, the adhesive layer 7b and the polarization separation film 7a. And is emitted from the third polarizing beam splitter 7 in a direction different from the direction returning to the first polarizing beam splitter 2.

  The first and second modulated lights emitted from the second polarization beam splitter 4 are incident on the third stacked phase difference filter 9. The third stacked phase difference filter 9 rotates the polarization plane of the first modulated light by 90 ° to transmit the first and second modulated lights, and passes through the fourth polarizing beam splitter 10 serving as a polarization combining element. Make it incident. At this time, the polarization planes of the first and second modulated lights are in the same direction. Further, the third modulated light emitted from the third polarizing beam splitter 7 passes through the fourth stacked phase difference filter 11 and enters the fourth polarizing beam splitter 10. The fourth laminated phase difference filter 11 rotates the polarization plane of the third modulated light by 90 ° and transmits it, and makes it incident on the fourth polarization beam splitter 10.

  Similarly to the first polarizing beam splitter 2, the fourth polarizing beam splitter 10 also includes a first triangular prism 101 having a polarizing separation film 10a formed on one surface by vapor deposition or the like, and the first triangular prism. The second triangular prism 102 bonded to the surface on which the polarization separation film 10a 101 is formed via the polarization separation film 10a and the adhesive layer 10b is formed in a cubic shape.

  In the fourth polarization beam splitter 10, the first and second modulated lights are P-polarized and the third modulated light is compared with the polarization separation film 10 a inclined at 45 ° with respect to the optical path of the incident light. S-polarized light. The first and second modulated lights pass through the polarization separation film 10a and the adhesive layer 10b, and are emitted from the fourth polarization beam splitter 10. The third modulated light is reflected by the polarization separation film 10 a and is emitted from the fourth polarization beam splitter 10. In this way, the first and second modulated light and the third modulated light are combined.

  The third modulated light emitted from the third polarization beam splitter 7 is incident on the fourth polarization beam splitter 10 from the first triangular prism 101 side. Therefore, the third modulated light is reflected by the polarization separation film 10 a without passing through the adhesive layer 10 b and is emitted from the first triangular prism 101.

  FIG. 2 is a plan view showing an optical path of the blue component light B in the color separation / synthesis optical system applied to the first embodiment.

  The blue component light B emitted from the first polarization beam splitter 2 is incident on a third polarization beam splitter 7 serving as a third polarization separation element. A blue light transmission filter 7 c may be disposed between the first polarization beam splitter 2 and the third polarization beam splitter 7. In the third polarizing beam splitter 7, after the incident blue component light B is transmitted through the adhesive layer 7b, the polarization separating film 7a inclined at 45 ° with respect to the optical path of the incident light, The blue component light B is S-polarized light. The blue component light B is reflected by the polarization separation film 7a, is emitted from the third polarization beam splitter 7, and is incident on the blue reflective spatial light modulator 8 which is the third spatial light modulator. The blue reflective spatial light modulator 8 is a so-called reflective liquid crystal display device, and reflects incident light by polarization-modulating the incident light according to the green component of the display image. Information of the display image is supplied to the blue reflective spatial light modulator 8 from the outside.

  The third modulated light modulated and reflected by the blue reflective spatial light modulator 8 is incident on the third polarization beam splitter 7 again. Since the third modulated light is P-polarized with respect to the polarization separation film 7a when the blue reflective spatial light modulation element 8 displays white, the adhesive layer 7b and the polarization separation film 7a. And is emitted from the third polarizing beam splitter 7 in a direction different from the direction returning to the first polarizing beam splitter 2.

  The first to third modulated lights emitted from the fourth polarizing beam splitter 10 are incident on the fifth stacked phase difference filter 12 as shown in FIG. The fifth laminated phase difference filter 12 transmits the first to third linearly polarized modulated light as circularly polarized light.

  As the fifth laminated phase difference filter 12, the polarization plane of the third modulated light is rotated by 90 degrees so that the first to third modulated lights are aligned in the same direction and further transmitted through the polarizing plate. You may do it. This polarizing plate removes unnecessary light having a different polarization plane direction.

  Light emitted from the fifth laminated phase difference filter 12 enters a projection optical system 19 that is an imaging optical system. The projection optical system 19 projects the first to third modulated light onto the screen 20 and displays an image.

  FIG. 3 is a schematic plan view illustrating a configuration of a color separation / synthesis optical system applied to the second embodiment.

  In the second embodiment, the first polarizing beam splitter 2 in the first embodiment is replaced with a flat wire grid type polarization separation element.

  That is, in this color separation / synthesis optical system, a light beam emitted from a light source (not shown) is made into a substantially parallel light beam and also into a linearly polarized light, and as shown in FIG. 1 is incident. Each of the color component lights R, B, and G of the incident light is linearly polarized and has the same plane of polarization. In the second embodiment, the polarization plane of each color component light of the incident light is in a direction parallel to the paper surface of FIG.

  In the light beam that has passed through the first laminated phase difference filter 1, the red component light R, the blue component light B, and the green component light G are each linearly polarized light, and the direction of the polarization plane of only the blue component light B is 90 °. It is rotated and the polarization plane of the blue component light B is orthogonal to the polarization planes of the red component light R and the green component light G.

  The light beam that has passed through the first laminated phase difference filter 1 is incident on a first wire grid type polarization separation element 21 that is a first polarization separation element. The first wire grid type polarization separation element 21 is disposed with an inclination of 45 ° with respect to the optical path of the incident light. The red component light R and the green component light G are P polarized light, and the blue component light B is Incident as S-polarized light. Therefore, in the first wire grid type polarization separation element 21, the red component light R and the green component light G are transmitted, the blue component light B is reflected, and the optical paths of the red component light R and the green component light G are The optical path of the blue component light B is branched according to the polarization plane direction.

  Regarding the red component light R and green component light G emitted from the first wire grid type polarization separation element 21 and the subsequent paths of the blue component light B reflected by the first wire grid type polarization separation element 21 This is the same as in the first embodiment.

  FIG. 4 is a schematic plan view showing a configuration of a color separation / synthesis optical system applied to the third embodiment.

  In the third embodiment, the first polarizing beam splitter 2 in the first embodiment is replaced with a dichroic wavelength separation film (dichroic filter).

  That is, in this color separation / synthesis optical system, a light beam emitted from a light source (not shown) is substantially a parallel light beam and is also linearly polarized, and as shown in FIG. 1 is incident. Each of the color component lights R, B, and G of the incident light is linearly polarized and has the same plane of polarization. In this embodiment, the polarization plane of each color component light of the incident light is in a direction parallel to the paper surface of FIG.

  In the light beam that has passed through the first laminated phase difference filter 1, the red component light R, the blue component light B, and the green component light G are each linearly polarized light, and the direction of the polarization plane of only the blue component light B is 90 °. It is rotated and the polarization plane of the blue component light B is orthogonal to the polarization planes of the red component light R and the green component light G.

  The light beam that has passed through the first laminated phase difference filter 1 is incident on the dichroic wavelength separation film 24. The dichroic wavelength separation film 24 is disposed with an inclination of 45 ° with respect to the optical path of the incident light, transmits the red component light R and the green component light G, and reflects the blue component light B. Therefore, in the dichroic wavelength separation film 24, the optical path of the red component light R and the green component light G and the optical path of the blue component light B are branched.

  Regarding the subsequent paths of the red component light R and the green component light G transmitted through the dichroic wavelength separation film 24 and the blue component light B reflected by the dichroic wavelength separation film 24, the above-described first embodiment and It is the same.

As described above, the first triangular prism in which the polarization separation film is formed on one surface by vapor deposition or the like, and the polarization separation film and the adhesive on the surface on which the polarization separation film of the first triangular prism is formed. In the polarizing beam splitter configured in a cubic shape from the second triangular prism bonded through the layers, the contrast becomes higher when the light beam is incident from the adhesive layer side. This is because the S-polarized wave reflectance, which is the polarization beam splitter characteristic that determines the contrast, becomes higher when the light beam is incident from the adhesive layer side.
The inventors have obtained a result that the contrast ratio is 1.3 to 1.5 times higher when the light beam is incident from the adhesive layer side and when the light beam is incident from the polarization separation film side.

  In each of the above-described embodiments, the path of the light beam of the third polarizing beam splitter is limited, but the present invention is applicable to the first polarizing beam splitter, the second polarizing beam splitter, and the fourth polarizing beam splitter in the first embodiment. Alternatively, the present invention may be applied to the second polarizing beam splitter and the fourth polarizing beam splitter in the second embodiment.

1 is a schematic plan view illustrating a configuration of an image display device applied to Example 1. FIG. FIG. 2 is a plan view showing an optical path of a blue component light B in the color separation / synthesis optical system applied to Example 1; 6 is a schematic plan view illustrating a configuration of a color separation / synthesis optical system applied to Example 2. FIG. 6 is a schematic plan view illustrating a configuration of a color separation / synthesis optical system applied to Example 3. FIG. It is a top view which shows the structure of the conventional color separation synthetic | combination optical system. It is a figure which shows a polarization beam splitter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lamination | stacking phase difference filter 2 1st polarization | polarized-light beam splitter 3 2nd lamination | stacking phase difference filter 4 2nd polarization | polarized-light beam splitter 5 Red reflection type spatial light modulation element 6 Green reflection type spatial light modulation element 7 1st 3 polarizing beam splitter 8 blue reflective spatial light modulator 9 third laminated phase difference filter 10 fourth polarizing beam splitter 11 fourth laminated phase difference filter 12 phase difference filter 13 illumination optical system 19 projection optical system

Claims (2)

First wavelength-selective polarization conversion means for entering a linearly polarized white light beam and setting the polarization planes of the red component light and green component light of the incident beam to be orthogonal to the polarization plane of the blue component light When,
A red light component and a green light component are provided by transmitting a P-polarized light component and reflecting an S-polarized light component with respect to the polarized light-separating film, and having a polarized light separating film on which the light beam having passed through the first wavelength selective polarization converting means is incident. A first polarization separation element for branching an optical path between the light and the blue component light;
Red component light and green component light are incident from the first polarization separation element, and the polarization plane of the first color component light and the polarization plane of the second color component light out of the red component light and the green component light. Second wavelength-selective polarization conversion means that are orthogonal to each other;
The first and second color component lights are incident from the second wavelength selective polarization conversion means, the first color component light is incident on the first spatial light modulator, and the second color component light is emitted. A second polarization separation element that is incident on the second spatial light modulation element;
A third polarization separation element that receives blue component light from the first polarization separation element and makes the blue component light incident on a third spatial light modulation element;
The modulated light of the red component light and the green component light that has passed through the first and second spatial light modulation elements and the modulated light of the blue component light that has passed through the third spatial light modulation element are incident, A polarization combining element that combines and emits; and
With
At least the third polarization separation element includes a first prism on which a polarization separation film is formed, and a surface of the first prism on which the polarization separation film is formed via the polarization separation film and an adhesive layer. A polarizing beam splitter comprising a second prism bonded together,
The blue component light traveling toward the third spatial light modulator is incident on the second prism, passes through the adhesive layer, is reflected by the polarization separation film, and is emitted from the second prism. A color separation / synthesis optical system. A color separation / synthesis optical system according to claim 1;
Light source means for making a light beam including at least a red component light, a green component light, and a blue component light in a linearly polarized state incident on the color separation / synthesis optical system;
An imaging optical system that forms an image of a light beam emitted from the polarization combining element of the color separation / synthesis optical system;
An image display device comprising:

Images