JP3711785B2 - Projection display device and illumination device used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection display device, and is particularly suitable for a projection display device that enlarges and projects an image of an electro-optical device using a reflective phase modulation element such as a reflective liquid crystal light valve.
[0002]
[Prior art]
Recently, in this type of projection display device (liquid crystal projector) using a phase modulation element such as liquid crystal, attention has been focused on the use of a reflection type phase modulation element such as a reflection type liquid crystal light valve. The reason for this is that, assuming the use of a light valve with a diagonal size of about 1 inch, which is suitable for reducing the size and weight of the entire display device, there is a limit to high resolution in transmissive light valves such as transmissive liquid crystal light valves. It can be raised. As an example, in a transmissive liquid crystal light valve, it is necessary to secure a pixel opening for transmitting a light beam, and as a result, a transistor as a switching element is inevitably downsized as resolution increases. As a result, sufficient transistor writing characteristics cannot be obtained. At present, it is said that a resolution of about SXGA is the limit in a transmission type liquid crystal light valve of about 1 inch.
[0003]
On the other hand, in reflective phase modulation elements such as reflective liquid crystal light valves, a reflective electrode can be provided on the pixel and a switching element can be formed on the lower side of the electrode, so that higher resolution than UVGA can be achieved. There is a feature.
[0004]
For these reasons, in the future, high-definition images from the market will be demanded, and reflective phase modulation elements such as reflective liquid crystal light valves are the most promising light valves for projection display devices. It is regarded as a candidate.
[0005]
Examples of the optical configuration of a projection display device using a reflection type phase modulation element can be broadly divided into a configuration using a polarization beam splitter as seen in SPIE Vol. 3296 P100, SPIE (to be published) documents and special features. The structure is divided into two, which does not use a polarizing beam splitter as seen in Kaihei 8-171078 and JP-A-8-94975.
[0006]
[Problems to be solved by the invention]
The configuration of the optical system using the above-described deflecting beam splitter will be described with reference to FIG. Light emitted from the lamp 101 passes through the rod 104 and the like for improving the illuminance ratio, and enters the polarization beam splitter 1601. The polarization beam splitter 1601 transmits P-polarized light and reflects S-polarized light (the reverse relationship can be realized depending on the configuration of the polarization separation film). The reflective liquid crystal light valve 108 gives a phase difference of λ / 4 to the light beam passing through the liquid crystal layer in the ON state by adjusting the birefringence, alignment state, and liquid crystal cell thickness of the liquid crystal material of the liquid crystal layer, It is configured to give a phase difference of 0 in the OFF state. This configuration is described in detail in the above-mentioned document SPIE Vol. 3296 P100, P19 and the like.
[0007]
The P-polarized light transmitted through the deflecting beam splitter 1601 enters the reflective liquid crystal light valve and is reflected by the reflective electrode. Then, since the light beam passes through the liquid crystal layer twice in the incident / reflecting optical path, the reflected light beam is converted into S-polarized light after receiving the phase difference of λ / 2 when the reflection type liquid crystal light valve is in the ON state, and subsequently incident. After being reflected by the polarization beam splitter 1601, it is projected onto the screen 111 by the projection lens 110 to provide a bright display. On the other hand, when OFF, the reflected light beam does not receive any phase difference, so it passes through the polarizing beam splitter 1601 again and returns to the illumination optical system side, and the light beam does not reach the screen 111 and is darkly displayed.
[0008]
The disadvantage of the optical system using this polarizing beam splitter is that the configuration of the entire optical system becomes complicated and the cost of parts increases. The dielectric multilayer film that has the polarization separation function of the polarizing beam splitter is designed for a limited wavelength band and light incident angle, so the wavelength band covering the entire visible range and wide light incident angle used in projection display devices. It is not possible to obtain a sufficient extinction ratio for illumination light having a brightness, and in order to obtain a projected image having a high contrast, it is necessary to use a dedicated polarization beam splitter for each of the R, G, B3 primary colors. . In this case, at least three polarizing beam splitters must be used, which leads to an increase in complexity and cost of the apparatus. In order to make up for such drawbacks, it is extremely difficult to obtain a sufficient extinction ratio even if a dielectric multilayer film design that covers the entire band with one polarization beam splitter is performed.
[0009]
Next, an optical system that does not use a polarizing beam splitter will be described. An important point in an optical system that does not use a polarization beam splitter is a configuration for spatially separating the illumination light beam and the projection light beam.
[0010]
The first example will be described with reference to FIG. The light emitted from the lamp 101 is collected by the condenser lens 103 and enters the reflective liquid crystal light valve 108 via the rod 104, the imaging lenses 105a and 105b, and the polarizing plate 106, which have the function of uniformizing the illuminance distribution. To do. The configuration and function of the reflective liquid crystal light valve 108 are the same as those described above. The light beam reflected by the reflective liquid crystal light valve 108 is guided to the projection lens 110 via the polarizing plate 109. Here, the incident-side polarizing plate 106 and the outgoing-side polarizing plate 109 are arranged in a crossed Nicols arrangement, so that in the ON state, the light beam undergoes a phase difference of λ / 2 and is converted into polarized light orthogonal to the incident polarized light. Is transmitted through the polarizing plate 109 on the side, and projected onto the screen 111 by the projection lens 110 to provide a bright display. On the other hand, when OFF, the light beam after reflection does not receive any phase difference and is absorbed by the polarizing plate 109 on the exit side, and the light beam does not reach the screen 111 and is darkly displayed.
[0011]
The disadvantage of this optical system is that it is inevitable that the image quality of the projected image is deteriorated and the cost is increased. In this configuration, since the illumination light is incident on the reflective liquid crystal light valve 108 at an angle, naturally the reflected light is also reflected at an angle. In order to project the reflected light onto the screen 111, it is generally preferable to place the projection lens 110 perpendicular to the optical axis of the reflected light. However, when viewed from the projection lens 110, the reflective light valve 108 is This is equivalent to being inclined with respect to the optical axis, and the screen projection image inevitably has trapezoidal distortion and various decentration aberrations, and the image quality is greatly deteriorated. In order to avoid such drawbacks, it is possible to improve the aberration by configuring the projection lens 110 with an eccentric lens or the like, but such a projection lens becomes very expensive and causes an increase in cost.
[0012]
In order to make up for such a drawback, as shown in FIG. 18, a configuration for minimizing the angular separation between the illumination light beam and the projection light beam has been proposed.
[0013]
In this configuration, the light emitted from the lamp 101 is collected by the condenser lens 103a and enters the reflective liquid crystal light valve 108 via the polarizing plate 106, the mirror 803, and the condenser lens 103b. The configuration and function of the reflective liquid crystal light valve 108 are the same as those described above. The light beam reflected by the reflective liquid crystal light valve 108 is collected by the condenser lens 103 b on the aperture formed by the aperture stop 804 and then guided to the projection lens 110 via the polarizing plate 109.
[0014]
In this configuration, the illumination light beam and the illumination light beam are narrowed at spatially close positions, and the condensing lens 103b is shared by both optical systems, so that the optical axis of the illumination optical system and the optical axis of the projection optical system can be reduced. Since the separation angle can be reduced as compared with the above-described example, the amount of decentration aberration of the projection optical system is reduced.
[0015]
A disadvantage of this optical system is that it is impossible to obtain a projected image with a high illuminance ratio. In order to obtain an image with a high current illuminance ratio, generally, a fly-eye lens or the like is used to form a plurality of secondary light source images distributed two-dimensionally and superimposed on the reflective liquid crystal light valve 108. Is used. When such a method is used, the width of the light beam in the illumination optical system inevitably has a certain thickness. However, in this optical system, the illumination light must be condensed in a narrow space area so that the illumination light and the projection light do not interfere with each other. This spatial region is not large enough to use all the light fluxes required in the illumination ratio improving optical system, and as a result, unevenness in illumination of the projected image becomes remarkable. If the separation angle of the projection light beam and the illumination light beam is increased in order to solve this problem, the amount of decentration aberration of the projection optical system has to be increased as in the configuration of FIG. This increases the cost of the lens.
[0016]
The present invention solves the above-described problems, and the object of the present invention is to provide a high contrast by using a polarization separation element that has high polarization separation capability and enables spatial separation of incident light and outgoing light. It is an object of the present invention to realize a projection display device using a reflection type phase modulation element capable of projecting a high-definition image having.
[0017]
[Means for Solving the Problems]
In order to solve the above-described problems, a projection display device according to the present invention combines a light source unit, an illumination optical unit that guides a light beam from the light source unit to a reflection type phase modulation element, and an image of the reflection type phase modulation element. Projection type display device comprising: imaging optical means for imaging; and an optical path from the light source means to the reflection type phase modulation element and a polarization separation means for substantially separating the optical path from the reflection type phase modulation element to the imaging optical means In the above, the polarization separation means exerts different refraction or diffraction action on each of the substantially linearly polarized light.
[0018]
According to this configuration, it is possible to configure a projection display device without using a polarization beam splitter because different polarization splitters that have different refraction or diffraction effects on each of substantially orthogonal linearly polarized light are used. Thus, the cost of the apparatus can be reduced and the image quality of the display image can be improved.
[0019]
In the projection display device, a light beam from the light source unit is incident on the reflection type phase modulation element substantially perpendicularly by the polarization separation unit.
[0020]
According to this configuration, since the optical axis of the projection lens can be arranged substantially perpendicular to the reflection type phase modulation element, the projection lens does not have any aberration due to decentration, and projects an image with very high image quality. Is possible. Furthermore, since a normal axially rotationally symmetric lens can be used, it is advantageous in terms of cost.
[0021]
Further, in the projection display device, the polarization separation means is composed of a combination of a prism element composed of a uniaxial crystal and a prism composed of an optically isotropic medium, and the refractive index of the uniaxial crystal with respect to ordinary light is set to no. When the refractive index for extraordinary light is ne, the refractive index of the optical isotropic medium is approximately no or approximately ne.
[0022]
With this configuration, it is possible to easily configure polarized light separating means that exerts a different refractive action on each of substantially orthogonal linearly polarized light, and a projection display device that can display a high-quality image at low cost. Can be realized.
[0023]
Furthermore, the polarization separation means is characterized in that a combination of prism elements made of uniaxial crystals and prisms made of an optically isotropic medium are arranged in an array.
[0024]
According to this configuration, the polarization separation element can be thinned.
[0025]
Further, in the projection display device, the polarization separation element includes a uniaxial crystal having an irregular periodic structure formed on a surface thereof and a structure in which a concave portion of the periodic structure is filled with an optically isotropic medium layer. When the refractive index of the crystalline crystal with respect to ordinary light is no and the refractive index with respect to extraordinary light is ne, the refractive index of the optical isotropic medium is approximately no or approximately ne, and the periodic structure diffracts incident light. It has the function to perform.
[0026]
With this configuration, it is possible to easily configure polarized light separating means that exerts a different diffractive action on each of substantially orthogonal linearly polarized light, and a projection display device that can display a high-quality image at low cost. Can be realized.
[0027]
In the projection display device, the polarization separation element is a surface relief type diffraction grating, and the grating pitch P satisfies the relationship of P <λ when the incident light wavelength is λ, and the depth of the grating Is characterized in that the diffraction efficiencies for the specific diffraction orders of linearly polarized light substantially orthogonal to each other are adjusted to be different.
[0028]
Compared with polarization separation means that has different diffractive action for each of substantially orthogonal linearly polarized light without using uniaxial crystals, polarization separation means that has different diffractive action for each of substantially orthogonal linearly polarized light. Can be manufactured inexpensively.
[0029]
In the projection display device, the polarization separation element is a volume hologram, and the grating pitch P satisfies a relation of P <λ when the incident light wavelength is λ, and the grating vector is the reflection phase. Inclined with respect to the modulation element.
[0030]
According to this configuration, polarized light having different diffractive action on each of substantially orthogonal linearly polarized light without mechanically processing the polarization separating means that has different diffractive action on each of substantially orthogonal linearly polarized light. Since the separating means can be manufactured at a relatively low cost and the direction of the grating vector can be easily adjusted, the incident angle of the illumination light to the reflective phase modulation element can be easily adjusted.
[0031]
Further, the polarization separation element having a diffraction action is inclined with respect to the reflection type phase modulation element.
[0032]
According to this configuration, it is easy to adjust the incident angle of the illumination light to the reflection type phase modulation element, so that the design of the polarization separation element is facilitated.
[0033]
Further, in the projection display device, the illumination optical unit divides the light beam from the light source unit into a plurality of light beams by internal reflection, and forms a plurality of secondary light source images, and the light beam splitting unit. And a light condensing means for imaging the illumination information of the light exit surface of the light beam onto the reflection type phase modulation element, wherein the shape of the light emission surface of the light beam splitting means is not similar to the planar shape of the reflection type phase modulation element. And
[0034]
According to this configuration, illumination light can be efficiently incident on the reflective phase modulation element obliquely.
[0035]
In the projection display device, the illumination optical means splits the light beam from the light source means into a plurality of light beams and emits them to form a plurality of secondary light source images, and the light beam splitting means emits the light. A light condensing unit that forms an image of surface illumination information on the reflection type phase modulation element, and an arrangement of the light exiting surface of the light beam dividing unit, the light condensing unit, and the reflection type phase modulation element satisfies Scheinpf's law. It is characterized by that.
[0036]
According to this configuration, illumination light can be efficiently incident on the reflective phase modulation element obliquely.
[0037]
In the projection display device, the illumination optical means splits the light beam from the light source means into a plurality of light beams and emits them to form a plurality of secondary light source images, and the light beam splitting means emits the light. Condensing means for imaging surface illumination information on the reflective phase modulation element, the condensing means including one or a plurality of decentered optical elements, and imaging of the exit surface information by the condensing means The position is changed for a while in the light flux from the light source means.
[0038]
According to this configuration, illumination light can be efficiently incident on the reflective phase modulation element obliquely.
[0039]
In the projection display device, the illumination optical means splits the light beam from the light source means into a plurality of light beams and emits them to form a plurality of secondary light source images, and the light beam splitting means emits the light. A light condensing unit that forms an image of the illumination information of the surface on the reflection type phase modulation element, and the exit surface of the light beam dividing unit and the reflection type phase modulation element are shifted at right angles to the light collection unit and in opposite directions. It is characterized by that.
[0040]
According to this configuration, illumination light can be efficiently incident on the reflective phase modulation element obliquely.
[0041]
Further, in the projection display device, L is a distance between an intersection of an extension line of the optical axis of the illumination optical system and a plane on which the reflective phase modulation element is disposed, and a substantially center of the reflective phase modulation element, A relationship of L> W is established, where W is the width of the reflection type phase modulation element in a plane including the optical axis of the illumination optical system and the normal line of the reflection type phase modulation element.
[0042]
According to this configuration, it is possible to prevent a component unnecessary for modulation of the reflection type phase modulation element, out of the substantially orthogonal linearly polarized light emitted from the illumination unit, from entering the reflection type phase modulation element. The number of linear polarizing plates can be reduced, and a brighter projection image can be obtained.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. In the following description, a case where a reflective liquid crystal light valve is used as the reflective phase modulation element will be described as an example. However, it goes without saying that the present invention is not limited to this.
[0044]
(First Embodiment of Projection Type Display Device and Polarization Separation Element)
FIG. 1 is a diagram showing a first embodiment of a projection display device according to the present invention.
[0045]
The projection display device of this embodiment includes a lamp 101 as a light source means, a reflector 102 as a reflection means, a condensing lens 103 as a first condensing means, a rod 104 as a light beam mixing means, 2 focusing means (imaging means), an imaging lens (condensing lens) 105 composed of lenses 105a and 105b, a first linear polarization element 106, and a polarization separation element 107 as polarization separation means. And a reflective liquid crystal light valve 108 as an image forming means, a second linearly polarizing element 109, and a projection lens 110, and an image of the reflective liquid crystal light valve 108 is displayed on the screen 110. The second light condensing means 105 has a function of forming an image of the exit end face of the rod 104 on the reflective liquid crystal light valve 107.
[0046]
Each of the first linear polarizing element 106 and the second linear polarizing element 109 transmits linearly polarized light having a vibration surface in a certain direction, and absorbs or reflects linearly polarized light having the vibration surface in a direction orthogonal thereto. They are placed in a crossed Nicol arrangement or a parallel arrangement with each other. This arrangement relationship is determined by the driving conditions of the reflective liquid crystal light valve. That is, when the reflective liquid crystal light valve is driven in a normally black condition for displaying black in the OFF state, it is necessary to have a crossed Nicols arrangement. On the contrary, when the reflective liquid crystal light valve is driven under normally white conditions for displaying white in the OFF state, it is necessary to arrange them in parallel. In the following description of the embodiment, the description will be made on the assumption that it is placed in a crossed Nicol arrangement for the sake of easy understanding.
[0047]
The light beam emitted from the lamp 101 is reflected by the parabolic reflector 102 and enters the condenser lens 103 as a substantially parallel light beam. The condensing lens 103 emits the light beam so as to enter the rod 104.
[0048]
The rod 104 is constituted by a columnar glass solid rod or a hollow rod in which a plurality of flat plate mirrors are combined on a column. The light beam incident on the rod 104 repeats internal reflection in the rod 104, and the light beam from various directions from the inside of the rod is superimposed on the exit surface, thereby reducing unevenness in brightness and increasing the illuminance ratio. An enhanced luminance distribution will be formed. The luminance distribution on the exit surface of the rod 104 is irradiated by the imaging lens 105 to the reflective liquid crystal light valve 108 as the irradiated surface via the linearly polarizing element 106 and the polarization separating element 107. The linearly polarizing element 106 has a function of transmitting polarized light (hereinafter referred to as P-polarized light) that vibrates in the plane of the paper and absorbing polarized light (hereinafter referred to as S-polarized light) that vibrates perpendicularly to the plane of the paper.
[0049]
FIG. 2 is a diagram showing a first embodiment of the polarization separation element according to the present invention.
[0050]
FIG. 2A shows the path of the light beam when the reflective liquid crystal light valve is in the ON state, and FIG. 2B shows the path of the light beam when in the OFF state.
[0051]
The polarization separation element 107 is configured by a combination of a uniaxial crystal prism 201 and an isotropic prism 202. Examples of the uniaxial crystal prism 201 include, but are not limited to, calcite, crystal, liquid crystal prism, and structural birefringent medium. In the following explanation, explanation is made on the assumption that a negative crystal such as calcite is used.
[0052]
The optical axis 203 of the uniaxial crystal prism 201 is in the plane of the paper, the refractive index for ordinary light is no, and the refractive index for extraordinary light is ne. Further, the refractive index of the isotropic prism 202 is adjusted to no.
[0053]
The P-polarized light 204 transmitted through the linearly polarizing plate 106 in FIG. 1 is refracted and incident on the uniaxial prism 201 according to Snell's law. Since this polarized light is extraordinary light in the uniaxial crystal prism 201, the refractive index of ne is felt. Then, the light is further refracted at the interface between the uniaxial prism 201 and the isotropic prism 202 and enters the liquid crystal layer 207 of the reflective liquid crystal light valve 108.
[0054]
At this time, the prism apex angles 205 and 206 are adjusted so that the incident angle of the incident P-polarized light 204 to the liquid crystal layer 207 is 0 °. For example, when calcite is used as the uniaxial crystal, since no = 1.658 and ne = 1.486, when the incident angle to the uniaxial crystal prism 201 of the P-polarized light 204 is about 9 °, If the apex angles 205 and 206 are formed to be approximately 47 °, the P-polarized light 204 can be incident on the liquid crystal layer 207 substantially vertically.
[0055]
In FIG. 2A, the reflective liquid crystal light valve 108 is in an ON state and has a function of giving a phase difference of λ / 4 to the light beam that has passed through the liquid crystal layer 207. Therefore, when the P-polarized light 204 incident on the liquid crystal cell 207 is reflected by the pixel electrode 208 and is emitted from the liquid crystal cell 207 again, it receives a phase difference of λ / 2 and is converted into S-polarized light 209. The S-polarized light 209 is not refracted at the interface between the uniaxial crystal prism 201 and the isotropic prism 202. This is because the refractive index of the uniaxial prism 201 for S-polarized light (= ordinary light) is no, which is equal to that of the isotropic prism 202. Accordingly, the S-polarized light 209 exits the polarization separation element 107 as it is.
[0056]
On the other hand, in FIG. 2B, the reflective liquid crystal light valve 108 is in the OFF state, and no phase difference is given to the light beam that passes through the liquid crystal layer 207. Therefore, even after the incident P-polarized light 204 is reflected by the pixel electrode 208, the polarization state remains P-polarized light, and returns to the illumination optical system side through the same path as when it was incident.
[0057]
As is clear from this, in this embodiment, the S-polarized outgoing light when the reflective liquid crystal cell light valve 108 is in the ON state and the P-polarized outgoing light when it is in the OFF state can be completely separated spatially. A very high extinction ratio can be obtained, which makes it possible to display a projected image having a high contrast.
[0058]
Returning to FIG. 1 again, the S-polarized light emitted from the polarization separation element 107 passes through the linear polarizer 109 in a crossed Nicols arrangement with respect to the linear polarizer 106, and is imaged on the screen 111 by the projection lens 110. Here, since the light reaching the screen is emitted substantially perpendicularly to the reflective liquid crystal light valve 108, the optical axis of the projection lens 110 can be disposed substantially perpendicular to the reflective liquid crystal light valve 108. Accordingly, since no aberration due to decentration occurs in the projection lens, it is possible to project an image having a very high image quality. Furthermore, since a normal axially rotationally symmetric lens can be used, it is advantageous in terms of cost.
[0059]
In the configuration of FIG. 1, the intersection point of the extension line 113 of the optical axis 112 of the illumination optical system and the extension line 114 of the reflective liquid crystal light valve 108 is defined as 115, and the intersection point 115 and the center point 116 of the reflective liquid crystal light valve 108. Let L be the distance. Further, the width of the reflective liquid crystal light valve 108 in the paper surface is W. At this time, the distance D between the polarization separation element 107 and the reflective liquid crystal light valve 108 and the angle θi formed between the optical axis 112 of the illumination optical system and the normal line of the polarization separation element are adjusted so that L> W. Thus, the linear polarizing plate 106 can be omitted. This is because the linearly polarizing plate 106 is installed to remove S-polarized light unnecessary for modulation of the reflective liquid crystal light valve. However, the linearly polarizing plate 106 can remove S-polarized light by making the relationship L> W. This is because the S-polarized light that hardly receives the refractive action by the polarization separation element 107 travels substantially straight as it is, and hardly enters the reflective liquid crystal light valve 108.
[0060]
According to this configuration, since the number of linearly polarizing plates can be reduced, the transmittance is improved accordingly, and a brighter projected image can be obtained. Needless to say, this configuration can be applied to the embodiments described below.
[0061]
(Second Embodiment of Polarization Separation Element)
FIG. 3 is a diagram showing a second embodiment of the polarization separation element.
[0062]
In this embodiment, the polarization separation element is a plane in which the combination unit 301 of the uniaxial crystal prism 201 and the isotropic prism 202 having the structure described in the first embodiment of the polarization separation element is parallel to the reflective phase modulator 108. It is the structure arranged on the array inside. According to this configuration, the polarization separation element 107 can be thinned, and the entire projection display device can be reduced in size and thickness.
[0063]
(Third embodiment of polarization separation element)
FIG. 4 is a diagram showing a third embodiment of the polarization separation element.
[0064]
4A shows the path of the light beam when the reflective liquid crystal light valve 108 is in the ON state, and FIG. 4B shows the path of the light beam when it is in the OFF state.
[0065]
In this embodiment, the polarization separation element 107 has a uniaxial crystal 401 in which a periodic grating 402 having a sawtooth cross section on the surface and a repetition pitch of P is formed, and an isotropic medium 403 filled in the gap of the grating 402. It consists of Examples of the uniaxial crystal 401 include, but are not limited to, calcite, crystal, liquid crystal prism, and structural birefringent medium. The optical axis 404 is in the plane of the paper, the refractive index for ordinary light is no, the refractive index for extraordinary light is ne, and the refractive index of the isotropic medium 403 is adjusted to no.
[0066]
Since the P-polarized light 204 incident on the polarization separation element 107 is abnormal light in the uniaxial crystal 401, the refractive index ne is sensed. Accordingly, the interface structure between the isotropic medium 403 and the uniaxial crystal 402 is affected. Since this interface structure is a periodic grating with a repetition pitch of P, the incident P-polarized light 204 is diffracted. The diffraction angle of the P-polarized light 204 is expressed by the following equation.
[0067]
n sinθ-n 'sinθ' = mλ / P
Here, n and n ′ are the refractive indices of the medium on the incident side and the exit side with respect to the diffractive surface, θ is the incident angle of light with respect to the diffractive surface, θ ′ is the exit angle, m is the order of the diffracted light, λ is the light wavelength, Is the pitch of the grid.
[0068]
Therefore, when calcite is used as the uniaxial crystal 401, the incident light wavelength is 0.633 μm of red light, and the incident angle is 30 °, the first-order diffracted light (m = 1) is substantially perpendicular to the liquid crystal layer 207. In order to make the light incident, the grating pitch P may be adjusted to about 1.3 μm. Further, since the cross-sectional shape of the grating 402 is a sawtooth shape, diffraction can be selectively generated in the primary direction, and most of the energy of the incident P-polarized light 204 is incident on the liquid crystal layer 207 perpendicularly. Can be made.
[0069]
As described in Embodiment 1, when the reflective liquid crystal light valve 108 is in the ON state, the reflected light is converted into S-polarized light 209 and is incident on the uniaxial crystal 401 again, and reaches the periodic grating 402. Here, since the S-polarized light 209 is ordinary light in the uniaxial crystal 401, the refractive index no is felt. Since this refractive index is the same as that of the isotropic medium 403, the S-polarized light 209 emits the polarization separation element 107 as it is without receiving an diffractive action without feeling the interface structure.
[0070]
On the other hand, in FIG. 3B, the reflective liquid crystal light valve 108 is in the OFF state, and no phase difference is given to the light beam that passes through the liquid crystal layer 207. Therefore, since the polarization state remains P-polarized light after reflection, it returns to the illumination optical system side through the same path as when it was incident.
[0071]
Therefore, as described in the first embodiment, it is possible to project a high-quality image with very high contrast. Since this embodiment uses the diffraction phenomenon, it has a feature that the separation angle between the incident P-polarized light and the outgoing S-polarized light can be made larger than that of the polarization separation element using the refraction phenomenon as in the first embodiment.
[0072]
(Fourth Embodiment of Polarization Separation Element)
5, FIG. 6 and FIG. 7 are diagrams showing an embodiment of a polarization separation element using a diffraction phenomenon as in the polarization separation element of the third embodiment.
[0073]
5A, 6 and 7A show the path of the light beam when the reflective liquid crystal light valve 108 is in the ON state, and FIGS. 5B and 7B show the light beam in the OFF state. The route is shown.
[0074]
Since the function of the polarization separation element of these embodiments is basically the same as that of the polarization separation element of Example 3, the overlapping description of the function is omitted, and only the difference in the structure of the polarization separation element is described. And
[0075]
5 has a relief type diffraction grating 501 formed on the surface thereof, and the grating vector 502 is in the plane of the paper. Further, the grating pitch P satisfies the relationship of λ> P when the wavelength used is λ. As described above, when a light wave is incident on a surface relief type diffraction grating whose grating pitch is shorter than the wavelength, it is known that the diffraction angle and the diffraction efficiency have a large polarization dependency. Further, it is known that the grating depth d has a great influence on the diffraction efficiency. (33th Applied Physics Lecture, 4a-ZC-1, 46th Correspondence Fall Lecture, 2p-H-6, 47th Correspondence Fall Lecture, 30p-V-6)
As an example, consider the case where the P-polarized light 204 is incident on the polarization separating element 107 tilted by θo with respect to the reflective liquid crystal light valve as shown in FIG.
[0076]
When the polarization separating element 107 is formed of a transparent plate having a refractive index of 1.66, the incident angle θi of the P polarized light 204 with respect to the polarizing molecular element 107 is approximately 30 °, the wavelength is 0.633 μm, the grating pitch P = 0.588 μm, When the grating depth is d = 1.47 μm, the first-order diffraction efficiency of the P-polarized light 204 reaches 90% or more, while the diffraction efficiency of the S-polarized light 209 is almost 0% and is transmitted with almost no diffraction effect. Further, since the diffraction angle θd of the first-order diffracted light is approximately 35 °, the incident P-polarized light 204 is incident on the liquid crystal layer 207 substantially vertically by tilting the polarization separation element 107 with respect to the reflective liquid crystal light valve by θo = 35 °. Can be made. Since the S-polarized light 209 reflected by the pixel electrode 208 and subjected to phase modulation hardly receives the diffracting action as described above, it passes through the polarization separation element 107 as it is.
[0077]
Therefore, by adjusting these parameters, the incident P-polarized light 204 is selectively diffracted to a specific order that is incident substantially perpendicularly to the liquid crystal layer 207, while the reflected S-polarized light 209 is selectively selected to the 0th order (straight forward transmitted light). If it is made to diffract, the polarization separation function can be exhibited.
[0078]
In the fourth embodiment and the embodiments that will be described later, the description has focused on the case where the polarization separation element 107 is disposed substantially parallel to the liquid crystal layer. However, as shown in FIG. 207 may be arranged with an inclination. By adopting such a configuration, it becomes possible to improve the diffraction efficiency of incident / exit polarized light into a specific order light and to improve the degree of freedom of design.
[0079]
This embodiment has a feature that a polarized light separating element can be manufactured at a relatively low cost because it is not necessary to use a uniaxial crystal as in the third embodiment. Furthermore, it has a feature that a larger separation angle can be obtained between incident P-polarized light and outgoing S-polarized light than a polarization separation element using a refraction phenomenon.
[0080]
The polarization separation element 107 in FIG. 7 is a volume hologram having a periodic structure 701 having a refractive index distribution therein, and the grating pitch P is determined when the wavelength used is λ.
The relationship of λ> P is satisfied. As described above, when a light wave is incident on a volume hologram having a grating pitch shorter than the wavelength, it is known that the diffraction angle and the diffraction efficiency have a large polarization dependency as in the polarization separation element of FIGS. . Therefore, the periodic structure pitch P is selected so that the P-polarized light 204 is selectively diffracted to a specific order that enters the liquid crystal cell substantially perpendicularly, while the reflected S-polarized light 209 is selectively diffracted to the 0th order (straight forward transmitted light). By adjusting various parameters of the volume hologram such as, it is possible to exhibit the polarization separation function.
[0081]
This embodiment is characterized in that it is not necessary to use a uniaxial crystal and it is not necessary to process a relief structure, so that a polarization separation element can be manufactured at a relatively low cost.
[0082]
Further, by making the periodic structure of the refractive index distribution formed inside the volume hologram into a distribution that can be approximated by a sine wave, the diffraction efficiency to a specific order can be extremely increased.
[0083]
Furthermore, it is possible to easily adjust the diffraction angle by adjusting the grating vector direction Φ, and the incident polarized light 204 can be easily made substantially vertical without tilting the polarization separating element 107 with respect to the reflective liquid crystal light valve. It becomes possible to make it enter.
[0084]
Has a characteristic that the separation angle between the incident P-polarized light and the outgoing S-polarized light can be made larger than that of the polarization separation element utilizing the refraction phenomenon.
[0085]
(Second Embodiment of Projection Display Device)
FIG. 8 is a diagram showing the overall configuration of the second embodiment of the projection display apparatus according to the present invention.
[0086]
The projection display device of the embodiment includes a lamp 101 as a light source means, a reflector 102 as a reflection means, a condensing lens 103 as a first light condensing means, a rod 104 as a light beam mixing means, and a second. Imaging lenses (condensing lenses) 801 and 802 as the focusing means (imaging means), the first linearly polarizing element 106, the mirror 803 as the reflecting means, and the polarization separating element 107 as the polarization separating means. A reflective liquid crystal light valve 108 as image forming means, an aperture stop 804 as light flux controlling means, a second linearly polarizing element 109, and a projection lens 805, and an image of the reflective liquid crystal light valve 108 is displayed on the screen. 110 is displayed. Further, the imaging lenses 801 and 802 as the second light condensing means have a function of forming an image of the exit end face of the rod 104 on the reflective liquid crystal light valve 107.
[0087]
The basic configuration of the embodiment is similar to the conventional technology described with reference to FIG. 18, and the projection light beam and the illumination light beam are narrowed at a relatively narrow angle by narrowing the projection light beam in a spatial region close to the narrow part of the illumination light beam. Are spatially separated.
[0088]
The problem with the prior art shown in the figure is that the separation angle θb between the projection light beam and the illumination light beam cannot be increased, and a sufficient space for the light beam generated by the illumination ratio improving optical system to pass through cannot be secured. However, since the polarization separation element 107 having the function described in the first to fourth embodiments is inserted in this configuration, the separation angle θa between the projection light beam and the illumination light beam can be made larger than that in the prior art. It is possible to secure a sufficient space through which the light beam generated by the ratio improving optical system passes. Therefore, a projection image with a high illuminance ratio can be obtained.
[0089]
(Third embodiment of the projection display device)
In the embodiments described so far, the description has been made on the assumption that the illumination light beam (or the optical axis of the illumination optical system) is substantially perpendicularly incident on the reflective liquid crystal light valve. However, the present invention is not limited to this condition, and various features can be exhibited even under conditions that deviate from this condition.
[0090]
FIG. 9 is a diagram showing the relationship between the incident angle of the illumination light beam to the reflective light valve and the angle separation between the illumination light beam and the projection light beam. FIG. 9A shows a case where the illumination light beam 901 is deflected by the polarization separation element 107 and enters the liquid crystal layer 207 of the reflective light valve substantially perpendicularly as in the embodiment described so far. 9B shows a case where the illumination light beam 901 is deflected by the polarization separation element 107 and is incident on the liquid crystal layer 207 of the reflection type light valve at an angle θc. FIG. In the figure, the illumination light beam 901 is incident on the liquid crystal layer 207 of the reflective light valve at an angle θd without passing through the polarization separation element. 9 indicates the separation angle between the illumination light beam 901 and the projection light beam 2, and θb indicates the angle formed by the projection light beam with respect to the normal line of the liquid crystal layer 207.
[0091]
The effect of the angles θa and θb in FIG. 9 on the performance of the projection display device will be described with reference to FIG.
[0092]
9, θa is an angle formed by the optical axis 1001 of the illumination optical system and the optical axis 1002 of the projection optical system in FIG. Each element in the illumination optical system must be disposed at a position that does not optically affect the light beam 1004 of the projection optical system. Similarly, each element in the projection optical system is optically related to the light beam 1003 of the illumination optical system. It must be placed in a position where it does not have a significant effect. Accordingly, the larger θa is, the closer the projection lens 110 can be to the reflective liquid crystal light valve. Assuming that the projection lens 110 has the same aperture, the closer the projection lens 110 is to the reflective liquid crystal light valve 108, the more reflected light from the reflective liquid crystal light valve 108 with a larger solid angle can be taken into the projection lens 110. That is, the F number of the projection lens 110 can be reduced, and a brighter projection image can be obtained.
[0093]
In summary, a brighter projected image can be obtained as θa is increased.
[0094]
Next, θb in FIG. 9 is an angle formed by the normal line 1005 of the reflective liquid crystal light valve 108 and the optical axis 1002 of the projection optical system in FIG. As this angle increases, the amount of eccentricity of the projection lens 110 with respect to the reflective liquid crystal light valve 108 increases, leading to deterioration of the image quality of the projected image. Conversely, the smaller this angle is, the higher the projected image quality can be obtained. To summarize the above, it is possible to obtain a projected image with higher image quality as θb is reduced.
[0095]
The feature of the configuration in which the illumination light beam (or the illumination optical system optical axis) is incident on the reflective liquid crystal light valve in a non-perpendicular manner will be described with reference to FIG. 9 again.
[0096]
FIG. 9A shows a case where the illumination light beam 901 is deflected by the polarization separation element 107 and enters the liquid crystal layer 207 of the reflective light valve substantially perpendicularly as in the embodiment described so far. . The incident angle of the illumination light beam 901 at that time to the polarization separation element 107 is θc. FIG. 9B shows a case where the illumination light beam 901 is incident on the polarization beam splitting element 107 having exactly the same structure as FIG. 9A at θd larger than θc. In this case, in view of Snell's law and diffraction angle law, the illumination light beam 901 is incident on the liquid crystal layer 207 of the reflective light valve at an angle θe larger than 0 °. Here, if the separation angle θa of the incident light beam 901 and the projection light beam 902 in (a) is A, then A = θc, and if the separation angle θa in (b) is B, then B = θd + θe.
[0097]
Since there is a relationship of θc <θd, clearly A <B. Therefore, for the reason described above, it can be said that the configuration of (b), that is, the configuration in which the illumination light beam (or the optical axis of the illumination optical system) is incident on the reflective liquid crystal light valve non-perpendicularly can obtain a brighter projection image.
[0098]
Next, let us consider a case where the configuration of FIG. 9B and the configuration of FIG. 9C without using a polarization separation element have exactly the same separation angle θa. At this time, if the angle θb formed by the projection light beam 902 with respect to the normal line of the liquid crystal layer 207 in (b) is C, C = θe, and if it is D in (c), D = θf. Further, as is apparent from the figure, in (b), θa = θg + 2θe, and in (c), since θa = 2θf, obviously, θe <θf, that is, C <D. Therefore, when obtaining a projected image having the same brightness, the configuration of (b), that is, the configuration in which the illumination light beam (or the optical axis of the illumination optical system) is incident non-perpendicularly on the reflective liquid crystal light valve is higher for the reason described above. It can be said that a projected image having image quality can be obtained.
[0099]
(Fourth Embodiment of Projection Display Device)
FIG. 11 is a diagram showing a configuration of an illumination optical system in the first embodiment of the projection display device.
[0100]
The end surface 1101 of the rod 104 on the imaging element 105a side is imaged on the reflective liquid crystal light valve 108 by the imaging lenses 105a and 105b. In order to transmit illumination light to the reflective light valve 108 without waste, the shape of the image of the end face 1101 needs to substantially match the planar shape of the reflective light valve 108. This is because when the former does not substantially match and the former is larger than the latter, a part of the illumination light is not guided to the screen, resulting in a decrease in illumination efficiency. Conversely, when the illumination light is small, the illumination light is irradiated to the reflective light valve. This is because a non-existent area is generated and the area is not projected at all.
[0101]
As is apparent from the figure, the end surface 1101 is not parallel to the reflective liquid crystal light valve 108. Therefore, in order to make the image shape substantially coincide with the planar shape of the reflective light valve 108, the shape of the end surface 1101 Should be similar to the shape obtained by projecting the planar shape of the reflective light valve 108 onto a plane parallel to the end face 1101. The similarity ratio at this time must be the reciprocal of the lateral magnification β of the imaging element 105.
[0102]
This relationship is shown in FIG. In FIG. 12, an arrow x indicates a direction perpendicular to the plane including the optical axis of the illumination optical system and the normal line of the reflective liquid crystal light valve. Further, the planar shape 1201 of the reflective light valve and the shape 1202 of the rod end surface are shown when viewed from the vertical direction.
[0103]
Since the horizontal direction of the planar shape 1201 of the reflective light valve and the horizontal direction of the end face of the rod are substantially parallel to each other, when the former length is A, the latter length a is approximately Appears.
[0104]
a = A / β where β is the lateral magnification of the imaging element 105.
[0105]
Since the vertical direction of the planar shape 1201 of the reflective light valve and the vertical direction of the end face of the rod are not parallel, the former must be projected onto a plane parallel to the latter. When the former length is B, the latter length b is approximately expressed by the following equation.
[0106]
b = B / (β · sin θi) where β is the lateral magnification of the imaging element 105
Θi is an angle formed by the optical axis of the illumination optical system and the normal line of the reflective liquid crystal light valve.
[0107]
(Fifth Embodiment of Projection Display Device)
In the configuration of the illumination optical system shown in FIG. 11, the optical path length of the light beam 1103 emitted from the upper end of the rod end surface 1101 to the reflection type phase modulator 108 and the reflection type liquid crystal light valve of the light beam 1104 emitted from the lower end of the rod end surface 1101. The optical path lengths up to 108 are different as is apparent from the figure. Accordingly, since the image 1105 of the rod end surface 4 is formed to be inclined with respect to the reflective liquid crystal light valve, the illumination light intensity distribution in the reflective liquid crystal light valve 108 does not faithfully reflect that on the rod end surface 1101. As a result, uneven illuminance occurs in the projected image. In order to avoid this phenomenon, the image of the rod end surface 1101 needs to be formed in a substantially flat shape on the reflective liquid crystal light valve plane.
[0108]
FIG. 13 shows a configuration in which the above phenomenon is avoided by using Shine-Pluff's law.
[0109]
Based on Shine-Pluff's law, in order to form an image on a plane inclined with respect to the imaging lens 105, the object may be tilted. For the inclination, the height from the optical axis 1307 of the illumination optical system at the intersection 1305 between the extension line 1301 of the rod end surface 1101 and the incident-side main plane 1302 of the imaging element 105 is h1, and the extension line 1304 of the polarization separation element 107 is obtained. When the height from the optical axis 1307 of the illumination optical system at the intersection 1306 of the exit-side main plane 1303 of the imaging element 105 is h2, h1 = h2 may be satisfied.
[0110]
FIG. 14 shows a configuration in which the above phenomenon is avoided by using a decentered optical element. In this configuration, all or some of the elements constituting the imaging element 105 are decentered elements. In FIG. 14, as an example, the imaging element 105 is configured by two lenses, and one of them 1401 is a decentered optical element. The decentered optical element 1401 has a decentered surface on the side of the polarization separation element 107, and has an aspherical shape in which the radius of curvature gradually increases from the bottom to the top of the figure. Since the power distribution is in-plane in this way, the light beam that has passed through the lower part of the power forms an image at a closer position, and the light beam that has passed through the lower part of the power forms an image at a farther position.
[0111]
When viewed from the rod end surface 1101, the reflective liquid crystal light valve is closer to the lower side and farther to the upper side. Therefore, the image of the rod end surface 1101 can be formed on the reflective liquid crystal light valve plane in a substantially planar shape by the imaging relationship of the decentered optical element 1401.
[0112]
FIG. 15 shows a configuration in which the above phenomenon is avoided by using a shift optical system. In this configuration, the rod end surface 1101 and the polarization separation element 107 are shifted from each other at right angles to the rotational symmetry axis 1501 of the imaging element 105 and in the opposite direction. In order to effectively guide the illumination light to the reflective liquid crystal light valve 108, the center point 1503 of the rod end surface 1101, the principal point of the imaging element 105, and the center 1506 of the polarization separation element 107 are the lamp 101, the reflector 102, and the light collecting element. The element 103 needs to be substantially disposed on the rotational symmetry axis 1502.
[0113]
(Deformation)
Without being limited to the embodiments described above, various modifications and changes can be made without departing from the spirit of the present invention.
[0114]
For example, the embodiment has been described by taking a reflective liquid crystal light valve as an example of a reflective phase modulation element, but other phase modulation elements may be used.
[0115]
Moreover, although the case where the polarization state of writing (illumination) light and reading (projection) light is different has been described as the bright display mode of the display element, a mode in which they are brightly displayed in the same polarization state may be used. It doesn't matter.
[0116]
Although the glass rod has been described as being solid, a light pipe that is hollow (a cylinder whose outer frame is glass and whose center is hollow. In this case, the light pipe reflects light on the inner surface of the glass) may be used.
[0117]
Further, the rod has been described as an example of the element having the function of improving the illuminance ratio, but another element, for example, two fly-eye lenses may be used.
[0118]
Further, the S-polarized light and the P-polarized light described in each figure may be reversed.
[0119]
【The invention's effect】
As described above in detail, according to the projection type display device of the present invention, a reflection type capable of projecting a high-definition image having high contrast by using a polarization separation element having polarization dependency in refraction or diffraction action. A projection display device using a phase modulator can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of a projection display device according to the present invention.
FIG. 2 is a diagram showing a first embodiment of a polarization beam splitting element according to the present invention.
FIG. 3 is a diagram showing a second embodiment of a polarization beam splitting element according to the present invention.
FIG. 4 is a diagram showing a third embodiment of a polarization beam splitting element according to the present invention.
FIG. 5 is a view showing a fourth embodiment of the polarization beam splitter according to the present invention.
FIG. 6 is an explanatory diagram of specific numerical examples of the polarization separation element according to the fourth embodiment of the present invention.
FIG. 7 is a view showing a fourth embodiment of the polarization beam splitter according to the present invention.
FIG. 8 is a diagram showing a second embodiment of the projection display device according to the present invention.
FIG. 9 is an explanatory diagram of the effect of the third embodiment of the projection display device according to the present invention.
FIG. 10 is a diagram showing a third embodiment of a projection display device according to the present invention.
FIG. 11 is a diagram showing a projection display device according to a fourth embodiment of the present invention.
FIG. 12 is an explanatory diagram of a specific example of the fourth embodiment of the projection display apparatus according to the present invention.
FIG. 13 is a diagram showing a fifth embodiment of a projection display apparatus according to the present invention.
FIG. 14 is a diagram showing a fifth embodiment of a projection display apparatus according to the present invention.
FIG. 15 is a diagram showing a fifth embodiment of the projection display apparatus according to the present invention.
FIG. 16 is an explanatory diagram of a conventional projection display device.
FIG. 17 is an explanatory diagram of a conventional projection display device.
FIG. 18 is an explanatory diagram of a conventional projection display device.
[Explanation of symbols]
101 lamp
102 reflector
103 condenser lens
104 rod
105 Imaging element
105a Imaging element
105b Imaging element
106 Linear polarizing plate
107 polarization separation element
108 reflective liquid crystal light valve
109 linear polarizing plate
110 Projection lens
111 screens
112 Optical axis of illumination optical system
113 Extension line of illumination optical system
114 Extension line of reflective liquid crystal light valve
115 intersection
116 Central point of reflective liquid crystal light valve
201 Uniaxial crystal prism
202 Isotropic prism
203 Optical axis
204 Incident P-polarized light
205 vertical angle
206 apex angle
207 Liquid crystal layer
208 Reflective electrode
301 Polarization separation element
401 Uniaxial crystal
402 Periodic grating
403 isotropic medium
404 optical axis
501 diffraction grating
502 lattice vector
701 Periodic structure of refractive index distribution
702 lattice vector
801 Imaging lens
802 Imaging lens
803 mirror
804 Aperture stop
805 projection lens
901 Illumination luminous flux
902 Projected luminous flux
1001 Illumination optical system optical axis
1002 Optical axis of projection optical system
1003 Illumination luminous flux
1004 Projected luminous flux
1005 Normal of reflective liquid crystal light valve
1101 End face of rod
1102 Upper ray
1103 Lower ray
1104 Normal of reflective liquid crystal light valve
1105 Image of rod end face
1201 Planar shape of reflective liquid crystal light valve
1202 Planar shape of rod end face
1301 Extension line of rod end face
1302 Incident side main plane of imaging element
1303 Output-side main plane of imaging element
1304 Extension line of polarization separation element
1305 intersection
1306 Intersection
1307 Optical axis of illumination optical system
1401 Eccentric optical element
1501 Center axis of imaging optical system
1502 Optical axis of illumination optical system
1503 Center of rod end face
1504 Center of imaging optical system
1505 Center of polarization separation element
1601 Polarizing beam splitter

Claims (13)

Light source means, illumination optical means for guiding a light beam from the light source means to a reflective phase modulation element, imaging optical means for forming an image of the reflective phase modulation element, and reflection type phase modulation from the light source means In the projection type display device comprising polarization separation means for substantially separating the optical path to the element and the optical path from the reflective phase modulation element to the imaging optical means, the polarization separation means is for each of the substantially linearly polarized light Projection type display device characterized by having different refraction or diffraction effects. 2. The projection display device according to claim 1, wherein a light beam from the light source means is incident on the reflection type phase modulation element substantially perpendicularly by the polarization separation means. 2. The projection type display device according to claim 1, wherein the polarization separating means is composed of a combination of a prism element composed of a uniaxial crystal and a prism composed of an optically isotropic medium. A projection display device, wherein the refractive index of the optically isotropic medium is approximately no or approximately ne when the refractive index is no and the refractive index for extraordinary light is ne. 4. The projection type display device according to claim 3, wherein the polarization separating means comprises a combination of prism elements made of uniaxial crystals and prisms made of an optically isotropic medium arranged in an array. An illumination device used for a projection display device. The projection display device according to claim 1, wherein the polarization separation element has a structure in which a uniaxial crystal having an irregular periodic structure formed on a surface and a concave portion of the periodic structure are filled with an optically isotropic medium layer. The refractive index of the optically isotropic medium is no or ne where the refractive index for ordinary light of the uniaxial crystal is no and the refractive index for extraordinary light is ne, and the periodic structure diffracts incident light. A projection display device having a function to act. 2. The projection display device according to claim 1, wherein the polarization separation element is a surface relief type diffraction grating, and the grating pitch P satisfies a relationship of P <λ when an incident light wavelength is λ. Is adjusted so that the diffraction efficiencies for the specific diffraction orders of linearly polarized light that are substantially orthogonal to each other are different from each other. 2. The projection display device according to claim 1, wherein the polarization separation element is a volume hologram, and a grating pitch P thereof satisfies a relationship of P <λ when an incident light wavelength is λ, and a grating vector thereof is A projection display device, wherein the projection display device is tilted with respect to the reflective phase modulation element. 8. A projection display device, wherein the polarization separation element according to claim 5 is tilted with respect to the reflection type phase modulation element. 2. The projection type display device according to claim 1, wherein the illumination optical unit divides the light beam from the light source unit into a plurality of light beams by internal reflection and emits the light to form a plurality of secondary light source images, Condensing means for imaging illumination information on the exit surface of the light beam splitting means on the reflection type phase modulation element, and the shape of the exit surface of the light beam splitting means is not similar to the planar shape of the reflection type phase modulation element A projection type display device characterized by that. 2. The projection type display device according to claim 1, wherein the illumination optical means divides the light beam from the light source means into a plurality of light beams and emits them to form a plurality of secondary light source images, and the light beam splitting. Condensing means for imaging illumination information on the exit surface of the means on the reflective phase modulation element, and the arrangement of the exit surface of the light beam splitting means, the condensing means and the reflective phase modulation element is Shine-Proff's law The illumination device used for the projection display device characterized by satisfying the above. 2. The projection display device according to claim 1, wherein the illumination optical means divides the light beam from the light source means into a plurality of light beams and emits them to form a plurality of secondary light source images, and the light beam splitting. A light condensing unit that forms an image of illumination information of the light exiting surface on the reflective phase modulation element, the light converging unit including one or a plurality of eccentric optical elements, and the light exiting surface information by the light converging unit The projection display apparatus is characterized in that the image forming position of the light source changes for a while in the light flux from the light source means. 2. The projection type display device according to claim 1, wherein the illumination optical means divides the light beam from the light source means into a plurality of light beams and emits them to form a plurality of secondary light source images, and the light beam splitting. A light condensing unit that forms an image of illumination information of the light exiting surface on the reflection type phase modulation element, and the light exiting surface of the beam splitting unit and the reflection type phase modulation element are perpendicular to and opposite to the light condensing unit. A projection display device characterized by being displaced. 2. The projection display device according to claim 1, wherein an intersection of an extension line of an optical axis of an illumination optical system and a plane on which the reflection type phase modulation element is arranged, and a distance between a substantially center of the reflection type phase modulation element. When L is W and the width of the reflective phase modulator in a plane including the normal axis of the illumination optical system and the normal line of the reflective phase modulation element is W, the relationship of L> W is established. Projection type display device.

Images