JP3646525B2 - Illumination optical system and projection display device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an illumination optical system using illumination light as linearly polarized light, and a projection display device using the illumination optical system.
[0002]
[Prior art]
One of devices that display a display screen such as a computer or a television is a projection display device. The projection display device modulates light emitted from a light source by an electro-optic effect device called a light valve, and projects the modulated light on a screen to display an image.
[0003]
A liquid crystal device is mainly used as a light valve of such a projection display device. In a liquid crystal device, a surface on which illumination light is incident is usually provided with a polarizing plate, and only predetermined linearly polarized light is used as illumination light, and other linearly polarized light is not used as illumination light. Therefore, in a projection display device in which illumination light having non-polarized light illuminates the liquid crystal device, the use efficiency of the illumination light is reduced, and the projection light is projected on the screen compared to the brightness of the illumination light. The image becomes dark. In order to solve this problem, conventionally, a polarization conversion optical system that converts non-polarized illumination light into linearly polarized light that can be used in a liquid crystal device has been used in the illumination optical system.
[0004]
FIG. 6 is a schematic plan view showing a main part of a conventional illumination optical system. The illumination optical system 1000 includes a lens array 1020, a polarization separation unit 1030, and a plurality of λ / 2 phase difference plates 1052. The polarization separation unit 1030 includes a polarization separation plate 1035 and a right-angle prism. The polarization separation plate 1035 includes a polarization separation film 1038 provided on one surface of the glass substrate 1036 and a reflection film 1039 provided on the other surface. The polarization separation plate 1035 is bonded to the right-angle prism 1031 so that the polarization separation film 1038 is in contact with the inclined surface 1034 of the right-angle prism 1031.
[0005]
A non-polarized light beam (light having both an s-polarized component and a p-polarized component) emitted from a light source (not shown) is divided into a plurality of partial light beams by a plurality of small lenses 1022 constituting the lens array 1020. The partial light beam emitted from one small lens 1022 enters the right-angle prism 1031 from the light incident surface 1032 and enters the polarization separation film 1038. At this time, due to the polarization separation action of the polarization separation film 1038, most of the s-polarized component constituting the partial light beam is reflected in a direction substantially perpendicular to the incident direction and proceeds in the direction of the exit surface 1033 of the right-angle prism 1031. On the other hand, the p-polarized component is almost transmitted through the polarization separation film 1038, reflected by the reflection film 1035 in a direction substantially perpendicular to the incident direction, and proceeds in the direction of the exit surface 1033 of the right-angle prism 1031. The s-polarized partial light beam and the p-polarized partial light beam are emitted from spatially separated positions on the exit surface 1033. The same applies to partial light beams emitted from the other small lenses 1022 of the lens array 1020. That is, the polarization separation unit 1030 separates each of the non-polarized partial light beams into two types of linearly polarized light, p-polarized light and s-polarized light.
[0006]
A λ / 2 phase difference plate 1052 is provided on each optical path of the p-polarized partial light beam emitted from the exit surface 1033 of the right-angle prism 1031. The p-polarized partial light beam is converted into an s-polarized partial light beam. The As a result, each of the partial light beams emitted from the lens array 1020 is almost converted into s-polarized light.
[0007]
As described above, the illumination optical system 1000 uses the polarization conversion optical system having the polarization separation unit 1030 and the plurality of λ / 2 phase difference plates 1052 to convert the non-polarized light beam emitted from the light source into almost one kind of straight line. By converting it into polarized light (s-polarized light), an illumination optical system with high utilization efficiency is realized.
[0008]
[Problems to be solved by the invention]
However, since the polarization separation film 1038 is formed by laminating a plurality of dielectrics, it is not easy to manufacture the polarization separation plate 1035 and the manufacturing cost is relatively high. . In addition, when the interface of the polarization separation film 1038 is in contact with air, it is difficult to design a film with good polarization separation characteristics. Therefore, the design of the film is usually performed under the condition that the interface is in contact with glass. . Therefore, the right-angle prism 1031 cannot be omitted in the conventional polarization separation unit 1030. Since this right-angle prism is relatively large and expensive, it is difficult to reduce the size and price. From the above, the conventional polarization conversion optical system has a problem that it cannot be easily configured.
[0009]
The present invention has been made in order to solve the above-described problems in the prior art, and by realizing a polarization conversion optical system with a simpler configuration compared to the prior art, an illumination optical system with high light utilization efficiency and this It is an object of the present invention to provide a projection display device using the above-mentioned.
[0010]
[Means for solving the problems and their functions and effects]
  In order to solve the above-described problems, the illumination optical system of the present invention includes:
  An illumination optical system for illuminating a predetermined illumination area,
  A light source that emits a non-polarized light beam;
  A light beam splitting optical system that splits a light beam emitted from the light source into a plurality of partial light beams;
  A polarization conversion optical system that converts the plurality of partial light beams into predetermined linearly polarized light and emits the light;
  A superimposing optical system that superimposes each of the plurality of partial light beams emitted from the polarization conversion optical system so as to illuminate the predetermined illumination area;
The light beam splitting optical system has a lens array that splits a light beam emitted from the light source into a plurality of partial light beams and collects each partial light beam,
  The polarization conversion optical system is
  Incident light fluxA reflective polarizing plate that separates into two types of linearly polarized light, reflects one linearly polarized light, and transmits the other linearly polarized light;Arranged parallel to the reflective polarizing plate,A reflective plate that reflects the other linearly polarized light transmitted through the reflective polarizing plate;For each of a plurality of partial light beams emitted from the lens array,One linearly polarized light reflected by the reflective polarizing plate and the other linearly polarized light reflected by the reflectorInA polarization separation unit that spatially separates;
  Ejected from the polarization separatorFor each of the plurality of partial luminous fluxesA polarization conversion unit that converts one polarization direction of the two types of linearly polarized light into the other polarization direction, and aligns the two types of linearly polarized light with predetermined linearly polarized light; To do.
[0011]
The illumination optical system is configured to substantially separate each of the plurality of partial light beams into two types of linearly polarized light by a reflective polarizing plate. Therefore, it is easier to manufacture the polarization separation unit than in the past. As a result, a polarization conversion optical system can be realized with a simpler configuration than in the past, and illumination optics with high light utilization efficiency can be provided.
[0012]
  In the illumination optical system,
  The reflection-type polarizing plate has light transmittance and reflectance adjusted so that the color of the illumination light that illuminates the predetermined illumination area becomes a predetermined color light.HaveIt is preferable. At this time, the reflection-type polarizing plate is adjusted so that light transmittance and reflectance in a specific wavelength region of incident light are higher than light transmittance and reflectance in other wavelength regions. You may do it. Alternatively, the reflective polarizing plate is adjusted so that the transmittance and reflectance of light in a specific wavelength region of incident light is lower than the transmittance and reflectance of light in other wavelength regions. It may be.
[0013]
If any of the above is performed, illumination light having a desired color balance can be realized.
[0014]
  The projection display device of the present invention is
  A projection display device that projects and displays an image on a screen,
  An electro-optic effect device that emits light that forms an image in response to a given image signal;
  An illumination optical system for irradiating illumination light to the electro-optic effect device;
  A projection optical system that projects light emitted from the electro-optic effect device and projects an image on the screen;
  With
  The illumination optical system includes:
  A light source that emits a non-polarized light beam;
  A light beam splitting optical system that splits a light beam emitted from the light source into a plurality of partial light beams;
  A polarization conversion optical system that converts the plurality of partial light beams into predetermined linearly polarized light and emits the light;
  A superimposing optical system that superimposes each of the plurality of partial light beams emitted from the polarization conversion optical system so as to illuminate the predetermined illumination area;
The light beam splitting optical system has a lens array that splits a light beam emitted from the light source into a plurality of partial light beams and collects each partial light beam,
  The polarization conversion optical system is
  Incident light fluxA reflective polarizing plate that separates into two types of linearly polarized light, reflects one linearly polarized light, and transmits the other linearly polarized light;Arranged parallel to the reflective polarizing plate,A reflective plate that reflects the other linearly polarized light transmitted through the reflective polarizing plate;For each of a plurality of partial light beams emitted from the lens array,One linearly polarized light reflected by the reflective polarizing plate and the other linearly polarized light reflected by the reflectorInA polarization separation unit that spatially separates;
  Ejected from the polarization separatorFor each of the plurality of partial luminous fluxesA polarization conversion unit that converts one polarization direction of the two types of linearly polarized light into the other polarization direction, and aligns the two types of linearly polarized light with predetermined linearly polarized light; To do.
[0015]
Since the projection display apparatus uses the illumination optical system, the same operations and effects as the illumination optical system can be obtained. Accordingly, it is possible to provide a projection display device having a simple configuration and high light use efficiency.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following description, the light traveling direction is the z direction, the 3 o'clock direction is the x direction, and the 12 o'clock direction is the y direction when viewed from the light traveling direction (z direction).
[0017]
A. Illumination optics:
FIG. 1 is a schematic plan view showing the main part of the illumination optical system of the present invention. The illumination optical system 100 includes a light source 110 that emits a substantially parallel light beam, a first lens array 120, a polarization separation plate 130, a second lens array 140, and a plurality of λ / 2 phase difference plates 152. The superimposing lens 160 is provided. The illumination optical system 100 is also an integrator optical system for illuminating the illumination region 180 substantially uniformly.
[0018]
The light source 110 includes a light source lamp 112 as a radiation light source that emits a radial light beam, and a concave mirror 114 that emits radiation light emitted from the light source lamp 112 as a substantially parallel light beam. As the light source lamp 112, a metal halide lamp or a high-pressure mercury lamp is usually used. As the concave mirror 114, a parabolic mirror is preferably used, but an ellipsoidal mirror or a spherical mirror can also be used.
[0019]
The first and second lens arrays 120 and 140 have a function as a light beam splitting optical system. Among them, the first lens array 120 has a function of dividing the light emitted from the light source 110 into a plurality of partial light beams and condensing each partial light beam. The second lens array 140 has a function of aligning the central axis of each partial light beam in parallel with the system optical axis SC. If the parallelism of the light emitted from the light source is excellent, the second lens array 140 can be omitted.
[0020]
FIG. 2 is a perspective view showing the appearance of the first lens array 120. The first lens array 120 has a configuration in which small lenses 122 having a substantially rectangular outline are arranged in M rows × N columns in an orthogonal matrix. Here, the x direction corresponds to the row direction of the lens array, and the y direction corresponds to the column direction. In this example, M = 6 and N = 4. Each small lens 122 of the first lens array 120 divides a light beam emitted from the light source 110 (FIG. 1) into a plurality of (that is, M × N) partial light beams, and each partial light beam is a second lens array. Light is condensed in the vicinity of 140. The outer shape of each small lens 122 viewed from the z direction is set to be substantially similar to the shape of the illumination region 180. In this embodiment, the aspect ratio (ratio between horizontal and vertical dimensions) of the small lens 122 is set to 4: 3. The second lens array 140 has a configuration in which small lenses twice as many as the small lenses 122 constituting the first lens array 120 are arranged in a matrix of M rows and NN columns. That is, two small lenses 142 and 143 arranged in the x direction of the second lens array 140 correspond to one of the small lenses 122 of the first lens array 120, and the x of the small lenses 142 and 143 corresponds. The width in the direction is about ½ of the width of the small lens 122 in the x direction. Note that NN = 2 × N.
[0021]
A polarization separation plate 130 shown in FIG. 1 includes a glass substrate 132, a reflective polarizing plate 134 attached to one surface of the glass substrate, and a reflection plate 136 attached to the other surface. . In this polarization separating plate 130, the surface of the reflective polarizing plate 134 faces the first lens array 120 and the second lens array 140, and the exit surface of the first lens array 120 and the reflective polarizing plate 134 are arranged. And the angle formed between the incident surface of the second lens array 140 and the reflective polarizing plate 134 is about 45 degrees. Therefore, the first lens array 120 and the second lens array 140 are arranged in directions perpendicular to each other.
[0022]
The polarization separation plate 130 functions with a plurality of λ / 2 phase difference plates 152 as described below.
[0023]
FIG. 3 is a schematic plan view showing the polarization separation plate 130, the first lens array 120, the second lens array 140, and a plurality of λ / 2 phase difference plates 152. In FIG. 3, for easy explanation, the central optical axis of one partial light beam among a plurality of partial light beams divided by the first lens array 120 is indicated by a solid line and a broken line. The non-polarized partial light beam emitted from the first lens array 120 (that is, the partial light beam having both the p-polarized component and the s-polarized component) is incident on the reflective polarizing plate 134 of the polarization separation plate 130. The reflective polarizing plate 134 has a function of mainly transmitting light in the set transmission axis direction and mainly reflecting light in the reflection axis direction. For example, the transmission axis is set in the direction of p-polarized light, and the reflection axis is set in the direction of s-polarized light. At this time, most of the s-polarized light component of the light contained in the partial light beam incident on the reflective polarizing plate 134 is reflected in a direction substantially perpendicular to the incident direction. On the other hand, the p-polarized light component passes through the reflective polarizing plate 134 as it is, and is reflected by the reflector 136 almost perpendicular to the incident direction. The s-polarized component reflected by the reflective polarizing plate 134 and the p-polarized component reflected by the reflector 136 are spatially separated from each other in the x-axis direction. The same applies to the other partial light beams divided by the other small lenses 122 of the first lens array 120. That is, the polarization separating plate 130 separates each of the non-polarized partial light beams into two types of linearly polarized light, p-polarized light and s-polarized light. The configuration of the reflective polarizing plate will be described later.
[0024]
The λ / 2 phase difference plate 152 is provided on the optical path of the p-polarized partial light beam between the reflection plate 136 and each small lens 143. In FIG. 3, the small lenses 143 are shown attached to the incident surface. The λ / 2 phase difference plate 152 converts the polarization direction of one linearly polarized light into the polarization direction of the other linearly polarized light out of the two types of linearly polarized light separated by the polarization separation plate 130. It has a function as a polarization conversion optical system for aligning the polarization direction of the linearly polarized light. In FIG. 3, each p-polarized partial beam is converted into an s-polarized partial beam. As a result, the plurality of partial light beams incident on the second lens array 140 are almost converted into s-polarized light. Note that a λ / 2 phase difference plate can be provided at a position where the s-polarized partial light beam passes to convert the light into almost p-polarized light.
[0025]
The polarization separation plate 130 corresponds to the polarization separation unit of the present invention, and the plurality of λ / 2 phase difference plates 152 correspond to the polarization conversion unit of the present invention. An optical system including the polarization separation plate 130 and the plurality of λ / 2 phase difference plates 152 corresponds to the polarization conversion optical system of the present invention.
[0026]
Here, the distance Dp between the two linearly polarized light beams separated from one partial light beam as described above is substantially equal to √2 times the thickness t of the polarization beam splitter 130. The second lens array 140 is preferably arranged so that the two linearly polarized lights separated from the respective partial light beams are just incident on the corresponding two small lenses 142 and 143 and effectively used. For example, when the center 134C of the reflection type polarizing plate 134 is arranged on the central optical axis 120LC of the first lens array 120, the second lens array 140 reflects the position of the central optical axis 140LC. It is preferable to dispose with respect to the center position 134C of the mold polarizing plate 134 so as to be shifted by Dp / 2 in the −X direction.
[0027]
Returning to FIG. 1, the superimposing lens 160 has a function as a superimposing optical system that superimposes the partial light beams emitted from the small lenses 142 and 143 of the second lens array 140 and condenses them in the illumination region 180. .
[0028]
The substantially parallel light beam emitted from the light source 110 is divided into a plurality of partial light beams by the plurality of small lenses 122 of the first lens array 120, and a secondary light source image is formed in the vicinity of the second lens array 140. It is condensed like an image. One partial light beam Lp (p + s) is a non-polarized partial light beam that enters the polarization separation plate 130 and passes through two different light beams Lpa ( s) and Lpb (p) are separated and injected. Here, the partial light beam Lpa (s) indicates s-polarized light, and Lpb (p) indicates p-polarized light. The s-polarized partial light beam Lpa (s) passes through the second lens array 140 and enters the superimposing lens 160. The partial light beam Lpa (s) incident on the superimposing lens 160 illuminates the illumination region 180 by the superimposing action of the superimposing lens 160. On the other hand, the p-polarized partial light beam Lpb (p) enters the λ / 2 phase difference plate 152, is converted into an s-polarized partial light beam Lpb (s), and is emitted. The partial light beam Lpb (s) incident on the superimposing lens 160 illuminates the illumination area 180 by the superimposing action of the superimposing lens 160, similarly to the partial light beam Lpa (s). Similarly, the other partial light beams divided by the first lens array 120 illuminate the illumination region 180. Therefore, the illumination optical system 100 emits a plurality of partial light beams almost aligned with s-polarized light and superimposes them by the superimposing action of the superimposing lens 160 to illuminate the illumination area 180 uniformly.
[0029]
In FIG. 1, the second lens array 140 and the superimposing lens 160 are shown separately, but these two types of lenses may be bonded together. Further, the superimposing lens 160 may be omitted, and an optical element having both the function of the second lens array 140 and the function of the superimposing lens 160 may be provided. Such an optical element can be realized by a lens array having a plurality of decentered lenses.
[0030]
In addition, the reflective polarizing plate 134 and the reflective plate 136 of the polarization separation plate 130 need not necessarily be disposed at an angle of 45 degrees with respect to the plurality of partial light beams divided by the first lens array 120. Absent. For example, it may be disposed at an angle greater than 45 degrees or may be disposed at an angle smaller than 45 degrees. That is, it is only necessary that each of the plurality of partial light beams incident on the polarization separation plate 130 be spatially separated into a p-polarized component and an s-polarized component.
[0031]
As described above, the reflective polarizing plate 134 provided on the glass substrate of the polarization separation plate 130 can obtain substantially the same effect as the polarization separation film described in the conventional example. The reflective polarizing plate 134 can be easily manufactured by attaching a reflective polarizing plate having desired reflection / transmission characteristics on the glass substrate 132. Further, the reflecting plate 136 can be easily manufactured by attaching a reflecting mirror such as an aluminum plate on the glass substrate 132. The reflection plate 136 may be a reflection type polarizing plate in which the polarization direction of light transmitted through the reflection type polarizing plate 134 is set to the reflection axis direction. The same reflection type polarizing plate as the reflection type polarizing plate 134 is used. Can be used. Therefore, the polarization conversion optical system including the polarization separation plate 130 can be realized with a simple configuration. In addition, since the reflective polarizing plate can determine its reflection / transmission characteristics by itself, the polarization conversion optical system using this can eliminate the need for a right-angle prism as in the conventional example. Miniaturization is also possible. However, a right angle prism may be provided. Moreover, you may provide a parallel plate glass.
[0032]
FIG. 4 is an explanatory diagram showing the configuration of the reflective polarizing plate. The reflective polarizing plate can be configured as a polymer material film having a multilayer structure. This multilayer structure film is composed of a laminate of films formed by stretching a polymer, and has a multilayer structure in which two different types of layers 601 (A layer) and 602 (B layer) are alternately laminated in the Z-axis direction. Have. For example, polyethylene naphthalate (PEN; polyethylene napthalate) is used for the A layer 601 of the reflective polarizing plate, and a copolyester (coPEN; naphthalene dicarboxylic acid and terephthalic acid) is used for the B layer 602. copolyester of napthalene dicarboxylic acid and terephthallic or isothalic acid) can be used. Of course, the material of the reflective polarizing plate used in the present invention is not limited to this, and the material can be appropriately selected.
[0033]
The refractive index (nax) in the x-axis direction and the refractive index (nay) in the y-axis direction of the A layer 601 are different from each other. On the other hand, the refractive index (nbx) in the x-axis direction and the refractive index (nby) in the y-axis direction of the B layer 602 are set to be substantially equal. Further, the refractive index (nay) of the A layer 601 in the y-axis direction and the refractive index (nby) of the B layer 602 in the y-axis direction are set to be substantially equal. That is, when this is summarized, (nax) ≠ (nay), (nbx) ≈ (nby) ≈ (nay). That is, the refractive index of each layer is substantially the same in the y-axis direction, and the refractive index of adjacent layers is different in the x-axis direction.
[0034]
Thus, in the y-axis direction, since there is substantially no difference in refractive index between the stacked layers, of the light incident on the multilayer structure film, linearly polarized light in the y-axis direction (s-polarized light in the embodiment) Light passes through this multilayer structure film while maintaining its polarization axis.
[0035]
On the other hand, regarding the polarization in the x-axis direction, the linearly polarized light in the x-axis direction is reflected by setting the film thicknesses of the A layer and the B layer as follows. That is, when the layer thickness in the z-axis direction of the A layer 601 is ta, the film thickness in the z-axis direction of the adjacent B layer 602 is tb, and the wavelength of light to be reflected is λ, the equation (1) The film thickness of one pair of A layer / B layer pair is set so that the relationship is obtained.
[0036]
ta · nax + tb · nbx≈λ / 2 (1)
[0037]
In this way, light of the wavelength λ that is linearly polarized light in the x-axis direction (p-polarized light in the embodiment) is reflected as polarized light in the x-axis direction at the interface between the adjacent A layer and B layer. become. A plurality of sets of A layer / B layer pairs in which the layer thicknesses ta and tb of the A layer 601 and the B layer 602 are variously changed are laminated, and the above-mentioned is applied over a wide range of wavelengths of the visible light or the color light to be modulated by the liquid crystal device. If the formula (1) is established, it is possible to reflect white light of linearly polarized light (p-polarized light) in the x-axis direction and incident color light. The multilayer structure film may be formed by sequentially laminating layers having different thicknesses, or may be formed by laminating a plurality of laminated bodies in which several layers having the same thickness are laminated. good. In the above formula (1), it is preferable that the equal sign is completely established.
[0038]
Therefore, in the reflective polarizing plate, the A layer 601 and the B layer 602 are set so that only light in a desired wavelength region is higher or lower than the transmittance / reflectance of light in other wavelength regions. The layer thicknesses ta and tb can be changed in various ways. In this way, the color balance of the illumination light emitted from the illumination optical system 100 can be variously adjusted. For example, when the blue light component of the light component of the light source is small, the reflection / transmission characteristic of the blue light of the reflective polarizing plate is set higher than that of the other color light, thereby providing illumination light with good color balance. be able to.
[0039]
B. Projection display:
FIG. 5 is a schematic plan view showing the main part of the projection display apparatus of the present invention. The projection display device 10 is a projection display device to which the illumination optical system 100 is applied.
[0040]
The projection display apparatus 10 includes an illumination optical system 100, dichroic mirrors 210 and 212, reflection mirrors 218, 222, and 224, an incident side lens 230, a relay lens 232, and three field lenses 240, 242, and the like. 244, three liquid crystal light valves (liquid crystal panels) 250, 252, and 254, a cross dichroic prism 260, and a projection lens system 270.
[0041]
As described above, the illumination optical system 100 emits linearly polarized light (in the above example, s-polarized light) whose polarization directions are aligned, and the liquid crystal light valves 250, 252, and 254 that are the illumination areas 180. Illuminate. Since the light incident surfaces of the liquid crystal light valves 250, 252, and 254 are usually provided with polarizing plates, the polarizing direction of the linearly polarized light emitted from the illumination optical system 100 is determined by the polarizing plates. The polarization direction is transmissive. In this way, the illumination light emitted from the illumination optical system 100 can be used efficiently.
[0042]
The two dichroic mirrors 210 and 212 have a function as color light separation means for separating the illumination light emitted from the illumination optical system into three color lights of red, green, and blue. The first dichroic mirror 210 transmits the red light component of the white light beam emitted from the illumination optical system 100 and reflects the blue light component and the green light component. The red light that has passed through the first dichroic mirror 210 is reflected by the reflection mirror 218, passes through the field lens 240, and reaches the liquid crystal light valve 250 for red light. The field lens 240 converts each partial light beam emitted from the second lens array 140 into a light beam parallel to the central axis. The same applies to the field lenses 242 and 244 provided in front of other liquid crystal light valves. Of the blue light and green light reflected by the first dichroic mirror 210, the green light is reflected by the second dichroic mirror 212, passes through the field lens 242 and reaches the liquid crystal light valve 252 for green light. On the other hand, the blue light passes through the second dichroic mirror 212, passes through the relay lens system including the incident side lens 230, the relay lens 232, and the reflection mirrors 222 and 224, and further passes through the field lens (exit side lens) 244. To the liquid crystal light valve 254 for blue light. The reason why the relay lens system is used for the blue light is that the length of the optical path of the blue light is longer than the length of the optical path of the other color light, so that a decrease in light use efficiency is prevented. That is, this is to transmit the partial light beam incident on the incident side lens 230 to the exit side lens 244 as it is.
[0043]
The three liquid crystal light valves 250, 252, and 254 function as an electro-optic effect device that emits light for forming an image by modulating light of three colors according to given image information (image signal). Have The cross dichroic prism 260 has a function as a color light combining optical system for combining three color lights emitted from the liquid crystal light valves 250, 252, and 254 to form a color image. In the cross dichroic prism 260, a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in an approximately X shape at the interface of four right-angle prisms. The three color lights are synthesized by these dielectric multilayer films to form synthesized light for projecting a color image. The combined light generated by the cross dichroic prism 260 is emitted in the direction of the projection lens system 270. The projection lens system 270 functions as a projection optical system, and enlarges and projects the combined light generated by the cross dichroic prism 260 on the projection screen 300 to display a color image.
[0044]
By using the illumination optical system 100, the projection display device 10 can realize a projection display device with a simple configuration and high light utilization efficiency.
[0045]
The present invention is not limited to the above examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.
[0046]
(1) In the above description of the projection display device, an example in which the illumination optical system of the present invention is applied to a transmissive projection display device has been described. However, the present invention also applies to a reflection projection display device. It is possible to apply. Here, “transmission type” means that the light modulation means such as a liquid crystal light valve transmits light, and “reflection type” means that the light modulation means reflects light. It means that there is. In a reflective projection display device, the cross dichroic prism can be used as a color light separating means for separating white light into three colors of red, green, and blue, and can also recombine the modulated three colors of light. It can also be used as color light combining means for emitting light in the same direction. Even when the present invention is applied to a reflective projection display device, substantially the same effect as that of a transmissive projection display device can be obtained.
[0047]
(2) In the above-described projection display device, a projection display device that displays a color image has been described as an example. However, the projection display device can also be applied to a projection display device that displays a monochrome image. Also in this case, the same effect as that of the projection display device can be obtained.
[0048]
(3) In the projection display device, a liquid crystal device (liquid crystal light valve) is described as an example of an electro-optical effect device. However, various electro-optical effect devices such as a DMD (digital micromirror device) display are used. It is applicable to a device to which Further, the present invention can be applied not only to a projection display device but also to a direct view display device.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a main part of an illumination optical system of the present invention.
FIG. 2 is a perspective view showing an appearance of a first lens array 120. FIG.
3 is a schematic plan view showing a polarization separation plate 130, a first lens array 120, a second lens array 140, and a plurality of λ / 2 phase difference plates 152. FIG.
FIG. 4 is an explanatory diagram showing a configuration of a reflective polarizing plate.
FIG. 5 is a schematic plan view showing the main part of the projection display apparatus of the present invention.
FIG. 6 is a schematic plan view showing a main part of a conventional illumination optical system.
[Explanation of symbols]
10. Projection display device
100: Illumination optical system
110: Light source
112 ... Light source lamp
114 ... concave mirror
120... First lens array
120LC ... Center optical axis
122 ... Small lens
130: Polarization separator
132 ... Glass substrate
134 ... reflective polarizing plate
136 ... reflector
140 ... second lens array
142 ... Small lens
143 ... Small lens
160 ... Superimposing lens
180 ... lighting area
210, 212 ... Dichroic mirror
218 ... Reflection mirror
222, 224 ... Reflection mirror
230 ... Incident side lens
232 ... Relay lens
240, 242, 244 ... Field lens
250, 252, 254 ... Liquid crystal light valve
260 ... Cross dichroic prism
270 ... Projection lens system
300 ... projection screen
601 ... A layer
602 ... B layer
1000: Illumination optical system
1020 ... Lens array
1022 ... Small lens
1030: Polarization separator
1031 ... Right angle prism
1032: Light incident surface
1033: Ejection surface
1034 ... Slope
1035: Reflective film
1035 ... Polarization separator
1036 ... Glass substrate
1038 ... Polarized light separation film
1039 ... Reflective film

Claims (5)

An illumination optical system for illuminating a predetermined illumination area,
A light source that emits a non-polarized light beam;
A light beam splitting optical system that splits a light beam emitted from the light source into a plurality of partial light beams;
A polarization conversion optical system that converts the plurality of partial light beams into predetermined linearly polarized light and emits the light;
A superimposing optical system that superimposes each of the plurality of partial light beams emitted from the polarization conversion optical system so as to illuminate the predetermined illumination area;
The light beam splitting optical system has a lens array that splits a light beam emitted from the light source into a plurality of partial light beams and collects each partial light beam,
The polarization conversion optical system is
The incident light beam is separated into two types of linearly polarized light, and one of the linearly polarized light is reflected and the other of the linearly polarized light is transmitted and arranged in parallel to the reflective polarizing plate. , and a reflecting plate for reflecting the reflective polarizer wherein the other of the linearly polarized light transmitted through, for each of the plurality of partial light fluxes emitted from the lens array, while being reflected by the reflective polarizer A polarization separation unit that spatially separates the linearly polarized light and the other linearly polarized light reflected by the reflector;
For each of the plurality of partial light beams emitted from the polarization separation unit, one of the two types of linearly polarized light is converted into the other polarization direction, and the two types of linearly polarized light are predetermined. A polarization conversion unit that aligns the linearly polarized light of
Illumination optical system. The illumination optical system according to claim 1,
In the reflective polarizing plate, the transmittance and reflectance of light are adjusted so that the color of the illumination light that illuminates the predetermined illumination area becomes a predetermined color light,
Illumination optical system. The illumination optical system according to claim 2,
The reflective polarizing plate is configured such that light transmittance and reflectance in a specific wavelength region of incident light are higher than light transmittance and reflectance in other wavelength regions.
Illumination optical system. The illumination optical system according to claim 2,
The reflective polarizing plate is configured such that light transmittance and reflectance in a specific wavelength region of incident light are lower than light transmittance and reflectance in other wavelength regions.
Illumination optical system. A projection display device that projects and displays an image on a screen,
An electro-optic effect device that emits light that forms an image in response to a given image signal;
An illumination optical system for irradiating illumination light to the electro-optic effect device;
A projection optical system that projects light emitted from the electro-optic effect device and projects an image on the screen;
With
The illumination optical system includes:
A light source that emits a non-polarized light beam;
A light beam splitting optical system that splits a light beam emitted from the light source into a plurality of partial light beams;
A polarization conversion optical system that converts the plurality of partial light beams into predetermined linearly polarized light and emits the light;
A superimposing optical system that superimposes each of the plurality of partial light beams emitted from the polarization conversion optical system so as to illuminate the predetermined illumination area;
The light beam splitting optical system has a lens array that splits a light beam emitted from the light source into a plurality of partial light beams and collects each partial light beam,
The polarization conversion optical system is
The incident light beam is separated into two types of linearly polarized light, and one of the linearly polarized light is reflected and the other of the linearly polarized light is transmitted and arranged in parallel to the reflective polarizing plate. , and a reflecting plate for reflecting the reflective polarizer wherein the other of the linearly polarized light transmitted through, for each of the plurality of partial light fluxes emitted from the lens array, while being reflected by the reflective polarizer A polarization separation unit that spatially separates the linearly polarized light and the other linearly polarized light reflected by the reflector;
For each of the plurality of partial light beams emitted from the polarization separation unit, one of the two types of linearly polarized light is converted into the other polarization direction, and the two types of linearly polarized light are predetermined. A polarization conversion unit that aligns the linearly polarized light of
Projection display device.

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