JP4432602B2 - Projection display - Google Patents

Description

  The present invention relates to a projection display device configured to display an image by using a polarization beam splitter unit that separates an incident light beam according to a polarization state of the incident light beam.

  Conventionally, a so-called “transmission type liquid crystal light valve” or “reflection type liquid crystal light valve” has been provided as a spatial light modulation element, and an image is displayed by enlarging and projecting light spatially modulated by the spatial light modulation element on a screen. A projection type display device configured as described above has been proposed.

  In this projection display device, white light from a light source is color-separated into three primary light colors of red (R), green (G), and blue (B), and three spatial light modulations are performed by these primary color lights. Each element is illuminated. Each spatial light modulator modulates the primary color illumination light according to the red component, the green component, and the blue component of the display image. Then, the modulated light that has passed through each of these spatial light modulation elements is polarized and separated, and then synthesized and projected onto the screen, whereby a color image is displayed on the screen.

  In such a projection display device, as described in Patent Document 1, an absorption-type polarizing plate is used as an optical element that polarizes and separates the modulated light that has passed through the spatial light modulation element. Such an absorption type polarizing plate is used when a “transmission type liquid crystal light valve” is used as a spatial light modulation element, and the modulated light transmitted through the “transmission type liquid crystal light valve” is incident on the modulated light. Among them, polarization separation is performed by transmitting only components in a predetermined polarization direction and absorbing other components.

  Further, as described in Patent Document 2, a glass prism type polarization beam splitter is used as an optical element that performs polarization separation. Such a polarizing beam splitter is used when a “reflective liquid crystal light valve” is used as a spatial light modulator, and transmits incident light from a light source to the “reflective liquid crystal light valve”. The modulated light reflected by the “reflective liquid crystal light valve” is re-entered, and the polarized light is separated by reflecting only the component of the predetermined polarization direction and transmitting the other component of the modulated light.

  Further, as described in Patent Document 3, a reflective polarizing element is used as an optical element for performing polarization separation. Such a reflective polarizing element is used when a “reflective liquid crystal light valve” is used as a spatial light modulator, and transmits incident light from a light source to the “reflective liquid crystal light valve”. The modulated light reflected by the “reflective liquid crystal light valve” is re-incident, and the polarized light is separated by reflecting only the component of the predetermined polarization direction and transmitting the other component of the modulated light.

This reflective polarizing element has the advantage that it is less damaged by heat generation than the glass prism type polarizing beam splitter, can prevent the contrast of the display image from being lowered, and can solve environmental problems in manufacturing. is there.
JP-A-6-148628 JP 2004-012864 A Japanese Patent Laid-Open No. 11-338053

  In the optical element that performs polarization separation as described above, the absorptive polarizing plate has a problem that it generates heat due to absorption of a light beam and is damaged by dissolution or the like. That is, since this absorption type polarizing plate absorbs a component that is not in a predetermined polarization direction, heat generation is inevitable, and when the amount of light emitted from the light source is increased, it is proportional to the increase in the amount of light. As a result, the calorific value increases.

  Therefore, in a projection display device using such an absorption-type polarizing plate as a polarization separation element, the amount of light emitted from the light source cannot be increased, and the display image cannot be sufficiently brightened.

  In addition, for a glass prism type polarization beam splitter, a glass material containing a large amount of lead oxide (PbO) with a small photoelastic coefficient (for example, “SF6” in order not to break the polarization state of transmitted light. ”,“ SF57 ”,“ PBH56 ”, etc.), and it becomes difficult to solve environmental problems.

  Furthermore, in such a polarizing beam splitter, the amount of light emitted from the light source is increased, and for example, in a projection type display device that displays an image with light intensity exceeding 10,000 lumens, birefringence in the glass material Occurrence of the image cannot be ignored, and the contrast of the display image is inevitably lowered.

  When the reflective polarizer is used in a projection display device, the light beam rejected by the reflective polarizer reaches the spatial light modulator and other optical components, thereby causing a ghost in the display image. There is a problem that flare occurs and the quality of the image decreases.

  When such a reflective polarizer is used, it is possible to prevent the luminous flux rejected by the reflective polarizer from affecting the display image by tilting the reflective polarizer with respect to the optical axis. However, in this case, there is a problem that decentration coma and astigmatism occur and the resolution of the display image is lowered.

  Therefore, the present invention is to provide a projection display device that can display a bright and high-contrast image and can easily solve environmental problems in a projection display device using a polarizing beam splitter unit. It is what.

In order to solve the above-described problems, a projection display device according to the present application includes a light source, a first polarizing element that receives light emitted from the light source, and converts the incident light to linearly polarized light. of a color separation prism for separating a linearly polarized light to the first to linearly polarized light of the third of the three primary colors emitted from the polarization element, the color separation of the first through separated by the prism third of the three primary colors of linearly polarized light Are arranged in correspondence with each other, modulate the linearly polarized light of the first to third primary colors according to the respective color components of the display image, and emit the modulated light of the first to third primary colors Are arranged so as to be inclined with respect to the optical axes of the modulated light beams of the first to third primary colors emitted from the three spatial light modulation elements . A reflective polarizing element that reflects the modulated light of the three primary colors, Color morphism polarizing element and the first to third three primary colors of modulated light reflected by the incident respectively, for the modulated light of the first to third of the three primary colors is incident as internally synthesized image light and synthesizing prism, and a projection optical system for projecting the image light synthesized in the color synthesizing prism, a position between the color combining prism and the reflection type polarizing element, the first to third 3 A second polarizing element that is arranged to be inclined with respect to the optical axis of the modulated light of the primary color and reflects and removes components in a predetermined polarization direction in the modulated light of the first to third primary colors, and three sheets wherein it is disposed at a position between the spatial light modulator and the reflective polarizing element, the first to third cylindrical lens and wedge prism having a flat surface inclined with respect to the optical axis of the modulated light of the three primary colors According to the inclination of the second polarizing element. An optical element for correcting aberrations generated, in which further comprising a.

  In the projection display device according to the present invention, the reflective polarizing element generates little heat, so that a sufficiently bright display image can be obtained by increasing the amount of light emitted from the light source, and the reflective polarizing element can be combined. Since there is little influence of refraction, there is no need to use a glass material containing a large amount of lead oxide (PbO), and further, the eccentric coma aberration generated by tilting the reflective polarizing element with respect to the optical axis, Since astigmatism is corrected by the wedge prism and the cylindrical lens or the wedge prism, the resolution of the display image does not decrease.

  According to the present invention, a projection display device using a polarization beam splitter unit can provide a bright and high-contrast image, and provide a projection display device that can easily solve environmental problems. Can do.

  Hereinafter, embodiments of a projection display device according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a perspective view showing the configuration of the projection type display apparatus according to the first embodiment of the present invention.

  In this projection type display device, as shown in FIG. 1, the light beam emitted from the light source 1 is transmitted through the UV / IR filter 2 to remove ultraviolet rays and infrared rays, and is condensed on the incident end face of the rod integrator 3. Incident. The light source 1 includes a discharge lamp that emits white light and a concave reflecting mirror (a spheroid mirror or a parabolic mirror).

  In the rod integrator 3, incident light repeatedly undergoes total internal reflection at the side surface of the rod, the illuminance is made uniform, and is emitted as light having a uniform spatial distribution from the emission end face.

  Light emitted from the rod integrator 3 is incident on a deflection mirror (steering mirror) 9 through a collimator lens 4, relay lenses 5 and 6, a PS synthesis element 7 and a condenser lens 8. The PS combining element 7 is an element that aligns light from a light source with linearly polarized light in a certain direction, and has a structure in which a plurality of polarizing beam splitters and half-wave plates are arranged in a planar shape. .

  The light incident on the deflecting mirror 9 is deflected 90 degrees in the optical path by the deflecting mirror 9. As the deflecting mirror 9, a cold mirror can be used in addition to an aluminum reflecting mirror and a silver mirror. The cold mirror is a mirror configured by laminating dielectric layers, and has a characteristic of transmitting ultraviolet light and infrared light and reflecting only visible light. The light reflected by the deflecting mirror 9 enters the color separation prism 10.

  FIG. 2 is a side view showing the shape of the color separation prism 10.

  As shown in FIG. 2, the color separation prism 10 is composed of three glass blocks including first and second triangular prisms 10A and 10B and a third prism (square prism prism) 10C.

  The color separation prism 10 is a so-called “Phillips prism”, and is a three-block color separation prism using selective reflection of color by a dichroic film and total reflection by a prism surface. The first dichroic film 11 that reflects blue light (B) is provided on the back surface of the first triangular prism 10A. The blue light (B) reflected by the first dichroic film 11 is totally reflected internally by the incident surface of the first triangular prism 10A. In this first triangular prism 10A, the apex angle (α1) of the prism is selected so that the blue light (B) is totally reflected on the inner surface, and the emission surface of the blue light (B) is in relation to the optical axis. The prism is shaped like a right angle.

  And the 2nd dichroic film | membrane 12 which reflects red light (R) is provided in the back surface of the 2nd triangular prism 10B, The red light (R) reflected by this 2nd dichroic film | membrane 12 is The inner surface is totally reflected by the incident surface of the second triangular prism 10B. In this second triangular prism 3B, the apex angle (α2) of the prism is selected so that the red light (R) is totally reflected on the inner surface, and the emission surface of the red light (R) is relative to the optical axis. The prism is shaped like a right angle. The first and second triangular prisms 10A and 10B use the back surface of the first triangular prism 10A and the second triangular prism 10B in order to use the incident surface of the second triangular prism 10B as a total reflection surface. It is assembled so that a very narrow air layer is maintained between the incident surface and the incident surface.

  Then, the green light (G) transmitted through the second dichroic film 12 is transmitted through the third prism 10C and emitted. The third prism 10C has a prism shape in which the emission surface of green light (G) is perpendicular to the optical axis.

  Such a color separation prism 10 is used in a so-called “three-plate” or “three-tube” color video camera apparatus. In a color video camera device, light is incident from a lens mount, and three CCDs (solid-state image sensors) and three image pickup tubes are installed on the primary color light emission surface of the color separation prism.

  In this projection display device, the light beam incident on the color separation prism 10 is incident from the incident surface of the first triangular prism 10 and is applied to the first dichroic film 11 on the back surface of the first triangular prism 10A. Incident light is transmitted through the first dichroic film 11, and cyan light (R + G) is transmitted and blue light (B) is reflected. The blue light (B) is totally internally reflected by the incident surface of the first triangular prism 10A and is emitted from the side surface of the first triangular prism 10A.

  The cyan light (R + G) transmitted through the first dichroic film 11 is incident on the second triangular prism 10B, is incident on the second dichroic film 12 on the back surface of the second triangular prism 10B, and this second In the dichroic film 12, green light (G) is transmitted and red light (R) is reflected. The red light (R) is totally internally reflected by the incident surface of the second triangular prism 10B and is emitted from the side surface of the second triangular prism 10B.

  The green light (G) that has passed through the second dichroic film 12 enters the third prism 10C, passes through the third prism 10C, and is emitted from the back surface of the third triangular prism 10C.

  In this way, the color-separated three primary color lights are incident on the deflecting prisms 13, 14, and 15, respectively, are deflected by 90 ° in the optical path, and travel in directions parallel to each other. In other words, the color-separated three primary color light travels in a direction perpendicular to the incident direction of light from the light source to the color separation prism 10 and the emission direction of each primary color light from the color separation prism 10.

  That is, as shown in FIG. 1, the blue deflection prism 13 is provided on the side surface of the first triangular prism 10A from which the blue light (B) is emitted. A red deflection prism 14 is provided on the side surface of the second triangular prism 10B from which red light (R) is emitted. A green deflection prism 15 is provided on the back surface of the third triangular prism 10C from which green light (G) is emitted.

  These deflection prisms 13, 14, and 15 are so-called right-angle prisms, and are triangular prisms having a right-angled isosceles triangle as a bottom surface.

  FIG. 3 is a perspective view showing a configuration around the color separation prism 10 and the color synthesis prism 20 in the first embodiment of the projection display apparatus according to the present invention.

  FIG. 4 is a side view showing a configuration around the color separation prism 10 and the color synthesis prism 20 in the first embodiment of the projection display apparatus according to the present invention.

  The three primary color lights emitted from the deflecting prisms 13, 14, and 15 and traveling in directions parallel to each other are incident on the transmissive light modulation elements 24, 25, and 26, respectively, as shown in FIGS.

  Each of the transmissive light modulation elements 24, 25, and 26 is driven by a corresponding drive circuit (not shown), and the blue transmissive light modulation element 24 performs spatial light modulation based on the blue component of the display image, and for red. The transmissive light modulation element 25 performs spatial light modulation based on the red component of the display image, and the green transmissive light modulation element 26 performs spatial light modulation based on the green component of the display image.

  A light beam (modulated light) transmitted through the transmission type light modulation elements 24, 25, and 26 is tilted with respect to the optical axis and a wedge prism having a surface inclined with respect to the optical axis constituting the polarization beam splitter unit. The light passes through the arranged cylindrical lens and is incident on the reflective polarizing elements 16, 17, and 18 arranged to be inclined with respect to the optical axis. The wedge prism and the cylindrical lens are an optical element 21 configured integrally. The inclination of the optical element 21 composed of the wedge prism and the cylindrical lens with respect to the optical axis is an inclination around an axis parallel to the inclination axis with respect to the optical axis of the reflective polarizing elements 16, 17 and 18.

  Of the light beams incident on the reflective polarizing elements 16, 17, 18, the modulated light components modulated by the transmissive light modulating elements 24, 25, 26 are reflected on the reflective surfaces of the reflective polarizing elements 16, 17, 18. On the other hand, it is S-polarized light. Therefore, the modulated light is reflected and deflected by the reflecting surface, and is incident on the color combining prism 20 configured in the same manner as the color separation prism 10. The P-polarized component of the light incident on the reflective polarizing elements 16, 17, and 18 is transmitted through the reflecting surface and is not incident on the color synthesis prism 20. That is, the reflective polarizing elements 16, 17, and 18 function as analyzers for the transmitted light of the transmissive light modulation elements 24, 25, and 26.

  Note that a polarizer 22 may be disposed between the reflective polarizing elements 16, 17, and 18 and the color combining prism 20 as described later in the fifth embodiment.

  In the blue light (B) incident on the blue transmissive light modulation element 24, the component which has been modulated by the blue transmissive light modulation element 24 and becomes S-polarized light is reflected by the reflective polarization element 16, The light enters from the side surface of the first triangular prism 20 </ b> A of the combining prism 20.

  In addition, the red light (R) incident on the red transmission light modulation element 25 is reflected by the reflection polarization element 17 as a component which is modulated by the red transmission light modulation element 25 and becomes S-polarized light. The light is incident from the side surface of the second triangular prism 20B of the color synthesis prism 20.

  The green light (G) incident on the green transmissive light modulation element 26 is reflected by the reflective polarization element 18 as a component that has been modulated by the green transmissive light modulation element 26 to become S-polarized light. Then, the light is incident from the back surface of the third prism 20C of the color synthesis prism 20.

  The color synthesizing prism 20 is configured to be substantially mirror-symmetric with respect to the color separation prism 10. That is, the color synthesis prism 20 has a configuration similar to that of a so-called “Phillips prism”, and includes three first and second triangular prisms 20A and 20B and a third prism (square prism prism) 20C. 3 color composition prism having a glass block and first and second dichroic films.

  The blue light (B) incident on the first triangular prism 20A of the color combining prism 20 is totally reflected on the inner surface by the emission surface of the first triangular prism 20A, reflected by the first dichroic film 27, The light is emitted from the emission surface of one triangular prism 20A.

  The red light (R) incident on the second triangular prism 20B of the color synthesizing prism 20 is totally reflected on the inner surface by the emission surface of the second triangular prism 20B, and reflected by the second dichroic film 28. The light is emitted from the emission surface of the second triangular prism 20B, passes through the first triangular prism 20A, and is emitted from the emission surface of the first triangular prism 20A.

  The green light (G) incident on the third prism 20C of the color combining prism 20 passes through the third prism 20C, passes through the second triangular prism 20B, and further passes through the first triangular prism 20A. The light passes through and is emitted from the emission surface of the first triangular prism 20A.

  In this way, the primary color lights incident on the color synthesis prism 20 are synthesized and emitted from the color synthesis block 20. As shown in FIG. 1, the light is incident on a projection lens 29 that is a projection optical system, and is projected onto a screen (not shown) by the projection lens 29.

  In this projection display device, the reflective polarizing elements 16, 17, and 18 are arranged so as to be inclined more than an angle corresponding to the F number of the projection lens 29 so that ghosts and flares in the display image do not occur.

  Astigmatism and decentered coma caused by the inclination of the reflective polarizing elements 16, 17, and 18 are corrected by generating opposite aberrations by the optical element 21 including a wedge prism and a cylindrical lens. In this embodiment, the F-number of the projection lens 29 is 2.8, and the inclination of the reflective polarizing elements 16, 17, 18 is 11 °. The optical element 21 may be composed only of a wedge prism.

  FIG. 5 is a side view showing ray tracing in the optical element for aberration correction in the first embodiment of the projection display apparatus according to the present invention.

  FIG. 6 is a spot diagram showing the state of aberration correction in the first embodiment of the projection display apparatus according to the present invention.

[Second Embodiment]
In the projection display device according to the second embodiment, as in the first embodiment described above, the light beam emitted from the light source passes through the UV / IR filter, and the ultraviolet rays and infrared rays are removed. The light is focused on the incident end face of the rod integrator.

  In the rod integrator, incident light repeatedly undergoes total internal reflection at the side surface of the rod, the illuminance is made uniform, and is emitted as light having a uniform spatial distribution from the emission end face. Light emitted from the rod integrator is incident on a deflection mirror (steering mirror) through a collimator lens, a relay lens, a PS synthesis element, and a condenser lens.

  FIG. 7 is a perspective view showing a configuration around the color separation prism 10 and the color synthesis prism 20 in the second embodiment of the projection display apparatus according to the present invention.

  The light incident on the deflecting mirror is deflected by 90 ° in the optical path by the deflecting mirror. The light reflected by the deflecting mirror enters the color separation prism 10 as shown in FIG. The color separation prism 10 is a so-called “Phillips prism”. The light beam incident on the color separation prism 10 is color-separated into three primary color lights.

  The three primary color lights color-separated by the color separation prism 10 are respectively incident on the deflection prisms 13, 14 and 15, are respectively deflected by 90 ° in the optical path, and travel in directions parallel to each other. In other words, the color-separated three primary color light travels in a direction perpendicular to the incident direction of light from the light source to the color separation prism 10 and the emission direction of each primary color light from the color separation prism 10.

  That is, the blue deflection prism 13 is provided on the side surface of the first triangular prism 10A from which the blue light (B) is emitted. A red deflection prism 14 is provided on the side surface of the second triangular prism 10B from which red light (R) is emitted. A green deflection prism 15 is provided on the back surface of the third triangular prism 10C from which green light (G) is emitted.

  These deflection prisms 13, 14, and 15 are so-called right-angle prisms, and are triangular prisms having a right-angled isosceles triangle as a bottom surface.

  FIG. 8 is a side view showing a configuration around the color separation prism 10 and the color synthesis prism 20 in the second embodiment of the projection display device according to the present invention.

  As shown in FIGS. 7 and 8, the three primary color lights emitted from the deflecting prisms 13, 14 and 15 and traveling in parallel directions are tilted with respect to the optical axes constituting the polarization beam splitter unit, respectively. Are incident on the reflective polarizing elements 16, 17 and 18.

  The light incident on the reflective polarizing elements 16, 17, 18 is S-polarized light with respect to the reflective surfaces of the reflective polarizing elements 16, 17, 18. Therefore, the incident light is reflected by the reflecting surface and passes through the wedge prism having a surface inclined with respect to the optical axis and the cylindrical lens arranged to be inclined with respect to the optical axis, and these reflective polarizing elements. The light is incident on the reflective light modulation elements 24, 25, and 26 for primary colors installed corresponding to 16, 17 and 18. The wedge prism and the cylindrical lens are an optical element 21a configured integrally. The inclination of the optical element 21a composed of the wedge prism and the cylindrical lens with respect to the optical axis is an inclination around an axis parallel to the inclination axis of the reflective polarizing elements 16, 17, and 18.

  Note that the P-polarized component of the light incident on the reflective polarizing elements 16, 17, and 18 does not reach each of the reflective light modulation elements 24, 25, and 26 because it passes through the reflective surface.

  Each of the reflection type light modulation elements 24, 25, and 26 is driven by a corresponding drive circuit (not shown), and the blue reflection type light modulation element 24 performs spatial light modulation based on the blue component of the display image, and for red. The reflective light modulation element 25 performs spatial light modulation based on the red component of the display image, and the green reflective light modulation element 26 performs spatial light modulation based on the green component of the display image.

  The blue light (B) incident on the blue reflection type light modulation element 24 is modulated and reflected by the blue reflection type light modulation element 24, and the component that has been modulated to become P-polarized light is reflected by the reflection type polarization element. 16 is transmitted through an optical element 21b integrally formed with a wedge prism having a surface inclined with respect to the optical axis and a cylindrical lens disposed with an inclination with respect to the optical axis, and is a color synthesis prism. The light enters from the side surface of 20 first triangular prisms 20A.

  The red light (R) incident on the red reflection type light modulation element 25 is modulated and reflected by the red reflection type light modulation element 25, and the component that has been modulated to become P-polarized light is reflected. The polarizing element 17 is transmitted through an optical element 21b integrally formed with a wedge prism having a surface inclined with respect to the optical axis and a cylindrical lens disposed with an inclination with respect to the optical axis. The light enters from the side surface of the second triangular prism 20B of the combining prism 20.

  The green light (G) incident on the green reflection type light modulation element 26 is modulated and reflected by the green reflection type light modulation element 26, and the component that has been modulated to become P-polarized light is reflected. The polarizing element 18 is transmitted through an optical element 21b integrally formed with a wedge prism having a surface inclined with respect to the optical axis and a cylindrical lens disposed with an inclination with respect to the optical axis. The light enters from the back surface of the third prism 20 </ b> C of the combining prism 20.

  The color synthesizing prism 20 is configured to be substantially mirror-symmetric with respect to the color separation prism 10. That is, the color synthesis prism 20 has a configuration similar to that of a so-called “Phillips prism”, and includes three first and second triangular prisms 20A and 20B and a third prism (square prism prism) 20C. 3 color composition prism having a glass block and first and second dichroic films.

  The blue light (B) incident on the first triangular prism 20A of the color synthesizing prism 20 is totally reflected on the inner surface by the emission surface of the first triangular prism 20A, reflected by the first dichroic film 27, The light is emitted from the emission surface of one triangular prism 20A.

  The red light (R) incident on the second triangular prism 20B of the color synthesizing prism 20 is totally reflected on the inner surface by the emission surface of the second triangular prism 20B, and reflected by the second dichroic film 28. The light is emitted from the emission surface of the second triangular prism 20B, passes through the first triangular prism 20A, and is emitted from the emission surface of the first triangular prism 20A.

  The green light (G) incident on the third prism 20C of the color combining prism 20 passes through the third prism 20C, passes through the second triangular prism 20B, and further passes through the first triangular prism 20A. The light passes through and is emitted from the emission surface of the first triangular prism 20A.

  In this way, the primary color lights incident on the color synthesis prism 20 are synthesized and emitted from the color synthesis block 20. And it injects into the projection lens which is a projection optical system, and is projected on a screen by this projection lens.

  In this projection type display device, when the inclination of each reflective polarizing element 16, 17, 18 is 45 ° with respect to the optical axis, the device configuration can be minimized. The occurrence is large, and the resolution of the display image projected on the screen is remarkably lowered. Therefore, in this projection type display device, the aberration is corrected by the optical elements 21a and 21b.

  When the reflective polarizing elements 16, 17, and 18 which are flat plates having a thickness of about 1 mm are installed with an inclination of 45 ° with respect to the optical axis, they are generated in the reflective polarizing elements 16, 17, and 18. There is a possibility that the correction of aberrations cannot be sufficiently corrected by a single cylindrical lens and wedge prism. Therefore, in this embodiment, good aberration correction is realized by the optical elements 21a and 21b in which the two cylindrical lenses and the wedge prism are integrally formed.

  FIG. 9 is a side view showing ray tracing in the optical element for aberration correction in the second embodiment of the projection display apparatus according to the present invention.

  FIG. 10 is a spot diagram showing the state of aberration correction in the second embodiment of the projection display apparatus according to the present invention.

[Third Embodiment]
FIG. 11 is a side view showing a configuration around the color separation prism 10 and the color synthesis prism 20 in the third embodiment of the projection display device according to the present invention.

  As shown in FIG. 11, the projection display device according to the present invention may be configured such that the optical elements 21a and 21b in the second embodiment described above are formed as wedge prisms by eliminating the cylindrical lens portion. Good.

  In this case, the aberration can be corrected satisfactorily, but the inclination of the optical elements 21a and 21b is increased and the apparatus configuration is increased as compared with the second embodiment. It is necessary to increase the focus accordingly.

  In this embodiment, it is easier to manufacture a polarization beam splitter unit than in the second embodiment.

  FIG. 12 is a side view showing ray tracing in the optical element for aberration correction in the third embodiment of the projection type display apparatus according to the present invention.

  FIG. 13 is a spot diagram showing the state of aberration correction in the third embodiment of the projection display apparatus according to the present invention.

[Fourth Embodiment]
FIG. 14 is a side view showing a configuration around the color separation prism 10 and the color synthesis prism 20 in the fourth embodiment of the projection display apparatus according to the present invention.

  As shown in FIG. 14, the projection type display apparatus according to the present invention comprises the optical elements 21a and 21b in the second embodiment described above as an optical element 21 composed of one cylindrical lens and a wedge prism. Also good.

  FIG. 15 is a side view showing ray tracing in the optical element for aberration correction in the fourth embodiment of the projection display apparatus according to the present invention.

  FIG. 16 is a spot diagram showing the state of aberration correction in the fourth embodiment of the projection display apparatus according to the present invention.

[Fifth Embodiment]
As shown in FIG. 4, the projection display device according to the present invention is arranged with respect to the optical axis between the reflective polarizing elements 16, 17, and 18 and the color synthesis prism 20 in the first embodiment described above. Alternatively, the polarizer 22 tilted may be arranged.

  That is, in the configuration in which the modulated light for displaying an image is reflected by the reflective polarizing elements 16, 17, and 18, the reflected light from the reflective polarizing elements 16, 17, and 18 disposed inclined with respect to the optical axis. Includes about 10% of unnecessary polarization direction components. Therefore, it is desirable to remove such an unnecessary polarization direction component by the polarizer 22.

  In addition, since the problem of heat_generation | fever will generate | occur | produce if an absorption type polarizer is used as this polarizer 22, it is desirable to use a reflection type polarizing element also as this polarizer. At this time, the polarizer 22 may be inclined by an angle corresponding to the F number of the projection lens in order to avoid the occurrence of ghost and flare in the display image. The aberration generated by the inclination of the polarizer 22 is corrected by the optical element 21.

  FIG. 17 is a side view showing ray tracing in the optical element for aberration correction in the fifth embodiment of the projection display apparatus according to the present invention.

  FIG. 18 is a spot diagram showing the state of aberration correction in the fifth embodiment of the projection display apparatus according to the present invention.

  As described above, the polarizing beam splitter unit of the present embodiment contains a large amount of lead oxide (PbO) because it generates little heat in the reflective polarizing element and is less affected by birefringence in the reflective polarizing element. In addition, it is not necessary to use glass materials, and decentration coma and astigmatism that occur when the reflective polarizing element is tilted with respect to the optical axis are corrected by the wedge prism and cylindrical lens, or the wedge prism. Is done.

  Therefore, in the projection display device of the present embodiment, a sufficiently bright display image can be obtained by increasing the amount of light emitted from the light source, and a glass material containing a large amount of lead oxide (PbO) is used. Therefore, it is easy to solve environmental problems, and further, decentration coma and astigmatism generated when the reflective polarizing element is tilted with respect to the optical axis may cause wedge prisms and cylindrical lenses, or Since it is corrected by the wedge prism, the resolution of the display image does not decrease.

  That is, according to the present embodiment, a projection display device using a polarization beam splitter unit can display a bright and high-contrast image, and can easily solve environmental problems. Can be provided.

It is a perspective view which shows the structure in 1st Embodiment of the projection type display apparatus which concerns on this invention. It is a side view which shows the shape of the color separation prism in 1st Embodiment of the said projection type display apparatus. FIG. 2 is a perspective view showing a configuration around a color separation prism and a color synthesis prism in the first embodiment of the projection display device. 2 is a side view showing a configuration around a color separation prism and a color synthesis prism in the first embodiment of the projection display device. FIG. It is a side view which shows the ray tracing in the optical element for the aberration correction in 1st Embodiment of the said projection type display apparatus. It is a spot diagram which shows the state of the aberration correction in 1st Embodiment of the said projection type display apparatus. It is a perspective view which shows the structure of the color separation prism and color composition prism periphery in 2nd Embodiment of the said projection type display apparatus. It is a side view which shows the structure around the color separation prism and color composition prism in 2nd Embodiment of the said projection type display apparatus. It is a side view which shows the ray tracing in the optical element for the aberration correction in 2nd Embodiment of the said projection type display apparatus. It is a spot diagram which shows the state of the aberration correction in 2nd Embodiment of the said projection type display apparatus. It is a side view which shows the structure around the color separation prism and color composition prism in 3rd Embodiment of the projection type display apparatus which concerns on this invention. It is a side view which shows the ray tracing in the optical element for the aberration correction in 3rd Embodiment of the said projection type display apparatus. It is a spot diagram which shows the state of the aberration correction in 3rd Embodiment of the said projection type display apparatus. It is a side view which shows the structure around the color separation prism and color composition prism in 4th Embodiment of the projection type display apparatus which concerns on this invention. It is a side view which shows the ray tracing in the optical element for the aberration correction in 4th Embodiment of the said projection type display apparatus. It is a spot diagram which shows the state of the aberration correction in 4th Embodiment of the said projection type display apparatus. It is a side view which shows the ray tracing in the optical element for the aberration correction in 5th Embodiment of the said projection type display apparatus. It is a spot diagram which shows the state of the aberration correction in 5th Embodiment of the said projection type display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 3 Rod integrator 5, 6, 8 Relay lens 7 PS synthesis | combination element 10 Color separation prism 13, 14, 15 Deflection prism 16, 17, 18 Reflection type polarization element 20 Color synthesis prism 21 Optical element 21a Optical element 21b Optical Element 24, 25, 26 Transmission type light modulation element, reflection type light modulation element 29 Projection lens

Claims (1)

A light source;
A first polarizing element that receives light emitted from the light source and converts the incident light into linearly polarized light;
A color separation prism that separates linearly polarized light emitted from the first polarizing element into linearly polarized light of first to third primary colors;
The first to third primary colors of linearly polarized light separated by the color separation prism are arranged corresponding to the first to third primary colors of linearly polarized light according to each color component of the display image. Three spatial light modulation elements that respectively modulate and emit as modulated light of the first to third primary colors ,
The first to third primary color modulated light beams are arranged so as to be inclined with respect to the optical axes of the first to third primary color modulated light beams emitted from the three spatial light modulation elements , respectively. A reflective polarizing element that reflects;
The reflective polarizing element modulating light of said first, second and third primary colors are reflected by the incident respectively, emits the modulated light of the first to third of the three primary colors is incident as internally synthesized image light A color synthesis prism;
A projection optical system for projecting the image light synthesized by the color synthesis prism ;
With
The first to third primary colors are arranged at a position between the reflective polarizing element and the color combining prism so as to be inclined with respect to the optical axis of the modulated light of the first to third primary colors. A second polarizing element that reflects and removes a component of a predetermined polarization direction in the modulated light of
Wherein the three of the spatial light modulator is disposed at a position between the reflective polarizing element, the first, cylindrical lens having a third flat surface inclined with respect to the optical axis of the three primary colors of modulated light and An optical element that has a wedge prism and corrects an aberration caused by an inclination of the second polarizing element;
A projection-type display device further comprising:

Images