JP3337022B2 - projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color separation optical system for separating a light beam emitted from a light source into three types of color lights, and modulating each color light separated by the color separation optical system in accordance with image information. The present invention relates to a projector including a light modulation optical system that forms an optical image for each color light and a color synthesis optical system that synthesizes an optical image for each color light formed by the light modulation optical system.

[0002]

2. Description of the Related Art As a color liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 4-60538, one dichroic mirror (electro-optical device) having a microlens array is specially arranged. 2. Description of the Related Art A single-panel projector having a mode of illuminating with color light separated by a color separation optical system) is known (hereinafter, such a projector is referred to as a spatial color separation type projector). In this type of projector, a color electro-optical device can be used to form a color projection image, so that the size of the projector can be easily reduced. On the other hand, a relatively bright projection image can be realized despite being a single-panel type. Have been.

FIG. 9 shows a main part of such a spatial color separation type projector. As shown in FIG. 9, the spatial color separation type projector 100 includes three dichroic mirrors 131R that reflect red (R), green (G), and blue (B) light,
131G and 131B are arranged at different angles with respect to the incident direction of the light beam, and the respective color lights separated by the three dichroic mirrors 131R, 131G and 131B enter the electro-optical device 150 from different directions. It is configured as follows. For example, the electro-optical device 150
The green light G has an incident angle of 0 degree and the red light R has an incident angle β
At 0, the blue light B is incident at an incident angle -β0. In the electro-optical device 150, as shown in FIG. 10, three rectangular sub-pixel electrodes 151R, 151G, and 151B corresponding to each color light of RGB are arranged side by side.
These three sub-pixel electrodes 151R, 151G, 151
One micro lens 153 is formed for B. Each color light incident on the micro lens 153 from a different direction is collected by the micro lens 153,
Each corresponding sub-pixel electrode 151R, 151G, 151B
And is modulated for each color light, and then emitted through a projection lens 190 to form a color projection image.

Here, the spatial color separation type projector 100
In the image forming area of one electro-optical device 150, R
Sub-pixel electrode 15 for independently modulating each color light of GB
It is necessary to arrange the 1R, 151G, and 151B juxtaposed in sets of three (such an electro-optical device is called a three-color modulation liquid crystal panel). Therefore, compared to the pixels of the electro-optical device used in the three-plate type projector, the sub-pixel electrodes 151R, 151G, 151 of the three-color modulation liquid crystal panel are compared.
The size of B is reduced to about 1/3.

[0005]

When the light beam is narrowed down by the light condensing function of the lens, the higher the parallelism of the light beam incident on the lens and the shorter the focal length of the lens, the smaller the sectional size of the light beam. (Light beam diameter) can be reduced. Conversely, if the focal length of the lens increases, the cross-sectional dimension of the light beam necessarily increases. Therefore, in the spatial color separation type projector 100, the electro-optical device 15
0, the sub-pixel electrodes 151R, 151G, 1
When miniaturizing 51B, the micro lens 15
3 has a shorter focal length, and the electro-optical device 150
It is necessary to narrow the light beam more narrowly so that the light beam incident on the sub-pixels can be made more parallel and can pass through sub-pixels of smaller dimensions. However, when such a short-focus microlens 153 is used, the divergence angle α of the converged light flux is used.
0 becomes very large.

Further, a spatial color separation type projector 100
In this case, since each of the RGB color lights separated by the color separation optical system enters the electro-optical device from a different direction with a certain angle (incident angle β0), the luminous flux from the electro-optical device 150 is the maximum. It becomes divergent light emitted at a large angle of α0 + β0. In order to collect the color light emitted at such a large angle (α0 + β0) by the projection lens 190 without leakage and form a projection image, the F value of the lens is small and the luminous flux diameter at the time of divergence of each color light is included. It is necessary to use a projection lens having a large diameter that can be used. However, there is a problem that such a lens is very expensive and large.

In addition, there is a limit in shortening the focal length of the micro lens 153 due to a limitation in a manufacturing method of the micro lens 153, and thus there is a limit in narrowing down the light beam.
Therefore, the sub-pixel electrodes 151R of the electro-optical device 150,
In the case where 151G and 151B are miniaturized, there is a problem that the light use efficiency in the electro-optical device 150 is reduced due to the relationship between the sub-pixel electrodes 151R, 151G and 151B and the cross-sectional dimensions of the light beam incident thereon.

Further, the sub-pixel electrodes 151R, 151
As G and 151B become smaller, illumination light flux with high parallelism is required. However, in order to obtain light flux with high parallelism, a light source lamp having a short arc length close to a point light source is required. However, existing light source lamps having a short arc length have problems in that it is difficult to increase the output and extend the life, and that the intensity of red light or blue light is weak.

Furthermore, as the pixels (sub-pixel electrodes 151R, 151G, 151B) of the electro-optical device 150 become smaller, higher relative positional accuracy is secured between the illumination optical system including the light source 110, the projection lens 190, and the like. Otherwise, it is difficult to bring optical properties such as brightness and color balance into a desired state.

An object of the present invention is to provide a projector which can easily bring optical characteristics such as brightness and color balance into a desired state and which is excellent in light use efficiency without using an expensive projection lens. Is to do.

[0011]

A first projector according to the present invention comprises a light source and a first color separation optical element for separating a light beam emitted from the light source into two types of color light, a first color light and another color light. A second color separation optical element for further separating the other color light separated by the first color separation optical element into two types of color light, a second color light and a third color light, wherein A second color separation optical element including a first mirror that reflects the color light and transmits the third color light, and a second mirror that reflects the third color light transmitted through the first mirror. A monochromatic modulation electro-optical device having a color separation optical system, a plurality of pixel electrodes, and the first color light from the first color separation optical element, and the second color separation electro-optical device from the second color separation optical element. And a microlens for receiving the third color light, and the second and the second And a plurality of sub-pixel electrodes corresponding to each of the three color lights, wherein the microlens comprises two sub-pixel electrodes of the second color light sub-pixel electrode and the third color light sub-pixel electrode. A two-color modulation electro-optical device provided at one ratio with respect to a color modulation electro-optical device, and a color synthesizing optical system that synthesizes each color light modulated by the monochromatic modulation electro-optical device and the two-color modulation electro-optical device. When three axes orthogonal to each other are defined as an X axis, a Y axis, and a Z axis, a traveling direction of light is defined as a Z axis direction, and a direction in which the color light is separated by the color separation optical system is defined as an X axis direction, The area and the X-axis dimension of the pixel electrode of the monochromatic modulation electro-optical device are as follows:
Area of the pixel electrode of the two-color modulation electro-optical device and X
The dimension in the Y-axis direction of the pixel electrode of the single-color modulation electro-optical device is set to approximately twice the dimension in the axial direction, and the dimension in the Y-axis direction of the sub-pixel electrode of the two-color modulation electro-optical device is set. It is characterized by being substantially the same as. Also, the second projector of the present invention includes a light source, a first color separation optical element for separating a light beam emitted from the light source into two types of color light of a first color light and another color light, and the first color separation optical element. A second color separation optical element for further separating the other color light separated by the optical element into two types of color light, a second color light and a third color light, wherein the second color light is reflected to reflect the third color light; A second color separation optical element including a first mirror that transmits the first color light and a second mirror that reflects the third color light that has passed through the first mirror; and A monochromatic modulation electro-optical device that includes a plurality of pixel electrodes and receives the first color light from the first color separation optical element, and receives the second and third color lights from the second color separation optical element And a micro lens corresponding to each of the second and third color lights. Includes a plurality of sub-pixel electrodes, wherein the microlens 1 with respect to the two sub-pixel electrodes of the said second sub-pixel electrode for the color light the third sub-pixel electrode for color light
A two-color modulation electro-optical device provided in two ratios, a color synthesizing optical system that synthesizes each color light modulated by the monochromatic modulation electro-optical device and the two-color modulation electro-optical device,
When three axes orthogonal to each other are defined as an X axis, a Y axis, and a Z axis, a traveling direction of light is defined as a Z axis direction, and a direction in which the color light is separated by the color separation optical system is defined as an X axis direction, Area and X of the pixel electrode of the monochromatic modulation electro-optical device
The dimensions in the axis and Y-axis directions are substantially the same as the area of the sub-pixel electrode of the two-color modulation electro-optical device and the dimensions in the X-axis and Y-axis directions.

Here, as the color separation optical system, a first color separation optical element for separating a light beam emitted from a light source into two types of color light, and a second color separation optical element separated by the first color separation optical element.
A color separation optical system including a second color separation optical element that further separates one of the two types of color light into two types of color light can be employed. As the first and second color separation optical elements, a dichroic mirror or a dichroic prism can be adopted.

As the color synthesizing optical system, a dichroic mirror or a dichroic prism can be employed as in the case of the color separation optical element.

The dichroic mirror has the advantages that it is relatively inexpensive and lightweight, and that the mirror surface, which is a photosynthetic surface, is likely to be warped, and that the optical path is shifted by the thickness of the mirror. On the other hand, the dichroic prism has the disadvantage that it is relatively expensive and heavy, and has the advantage that no warpage or optical path shift occurs in the photosynthetic surface. Therefore, it is desirable to use a dichroic mirror for a color separation optical system that does not require high-precision light flux separation, and to use a dichroic prism for a color synthesis optical system that requires high-precision light flux synthesis.

According to the present invention, since the light modulating optical system includes the monochromatic modulating electro-optical device and the two-color modulating electro-optical device, the optical characteristics such as brightness and color balance can be adjusted to a desired state. It is easy to reduce the cost, and it is not necessary to use an expensive lens. That is, in the case of the two-color modulation electro-optical device, the size of the pixels forming the image forming area can be increased as compared to the case where three color lights are modulated by one electro-optical device.
When the size of the pixel is increased, the condensing angle of the microlens disposed at the preceding stage can be reduced, and the divergence angle of the light beam emitted from the electro-optical device can be reduced. Further, since the color light incident on one electro-optical device is a maximum of two colors, the separation angle at the time of separating the two colors of light by the color separation optical system is reduced so that the two-color modulation electro-optical device can be used. The light beam can be incident at a small incident angle, and accordingly, the divergence angle of the light beam emitted from the two-color modulation electro-optical device can be further reduced. Further, since the projector can be configured by two electro-optical devices, the cost can be reduced as compared with the three-plate type projector.

In the above, the monochromatic modulation electro-optical device is
It is preferable that a microlens is provided on the substrate on the color separation optical system side. That is, since the microlens is also provided on the substrate on the color separation optical system side of the monochromatic modulation electro-optical device, the light use efficiency in the monochromatic modulation electro-optical device can be improved, and the device is brighter and has excellent color balance. Projected image can be realized.

Further, three axes orthogonal to each other are defined as an X axis and a Y axis.
When the traveling direction of light is the Z-axis direction, and the direction in which color light is separated by the color separation optical system is the X-axis direction,
The area of the pixel electrode and the dimension in the X-axis direction of the monochromatic modulation electro-optical device are set to approximately twice the area of the pixel electrode and the dimension in the X-axis direction of the two-color modulation electro-optical device. It is conceivable that the dimension of the pixel electrode in the Y-axis direction is substantially the same as the dimension of the pixel of the two-color modulation electro-optical device in the Y-axis direction. That is, if each pixel of the monochromatic modulation electro-optical device and the two-color modulation electro-optical device is set in this way, the number of pixels constituting the image forming area of each electro-optical device becomes the same, so that the monochromatic modulation electro-optical device Is approximately twice as large as that of the two-color modulation electro-optical device. Therefore, if the light is input to the color light monochromatic modulation electro-optical device having low light intensity, a projected image excellent in brightness and color balance can be realized.

On the other hand, conversely, the area of the pixel electrode and the dimensions in the X-axis and Y-axis directions of the monochromatic modulation electro-optical device are set to 2
It is conceivable that the area of the pixel electrode and the dimensions in the X-axis and Y-axis directions of the color modulation electro-optical device are substantially the same. In this case, it is preferable that the monochromatic modulation electro-optical device modulates green light.

That is, in this case, the number of pixels in the image forming area of the monochromatic electro-optical device is approximately twice the number of pixels for each color light of the two-color electro-optical device. The resolution of the color light modulated by the electro-optical device can be increased. In particular, the observer's perception of the resolution is easily affected by the resolution of the green light. Therefore, if the green light is modulated by the monochromatic modulation electro-optical device, the observer can be made aware that the projected image has a high resolution.

When the area of the pixel electrode of the monochromatic modulation electro-optical device is the same as the area of the pixel for each color light of the two-color modulation electro-optical device, the arrangement of the pixels in the image forming area of the monochromatic modulation electro-optical device is It is preferable that the two-color modulation electro-optical device correspond to the pixel arrangement in the image forming area at a position shifted by 画素 pixel. Further, it is more preferable that the shift of 1/2 pixel is in the X-axis direction (direction in which the color light is separated). That is, since a shift of 1/2 pixel is generated in this way, when the light beams emitted from both electro-optical devices are combined by the color combining optical system, the pixel structures arranged in a plane can be made inconspicuous. In addition, the visibility of the projected image can be improved, and high resolution can be realized. Also,
If the pixel structure is shifted in the X-axis direction (the direction in which the color light is separated, that is, the horizontal direction in the electro-optical device), the pixel structure can be made more inconspicuous from human visual characteristics.

Further, when the monochromatic modulation electro-optical device does not modulate green light, it is preferable to modulate red light or blue light. Unfortunately, there are no light source lamps used in projectors that have an ideal intensity ratio of red light, green light, and blue light.For example, ultra-high pressure mercury lamps and some metal halide lamps use red light. In contrast, halogen lamps, xenon lamps, and some metal halide lamps have little blue light. Therefore, if the monochromatic modulation electro-optical device is set so as to modulate the color light whose light intensity is smaller than the ideal value, the monochromatic modulation electro-optic having a large number of pixels or a large pixel area can be used even if the light source lamp as described above is used. Since the color light having a low light intensity can be used without waste by using the apparatus, it is possible to realize a projection image having an excellent color balance by balancing the intensity with other color light.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1. First Embodiment FIG. 1 is a schematic diagram illustrating a structure of a projector according to a first embodiment of the invention. This projector includes a light source 10, a color separation optical system 30, a light modulation optical system 50,
A color combining optical system 70 and a projection lens 90 as a projection optical system are provided. The luminous flux emitted from the light source 10 is
The color separation optical system 30 separates the light into three types of color light, and the light modulation optical system 50 forms an optical image corresponding to the image information for each color light. These optical images are synthesized by the color synthesis optical system 70. Then, the image is enlarged and projected as a color image on a screen by the projection lens 90. Here, in the present embodiment, the traveling direction of the light beam is the Z-axis direction, the X-axis direction is the 3 o'clock direction toward the Z-axis direction, and the Y-axis direction is the 12:00 o'clock direction.

Although not shown in FIG. 1, between the light source 10 and the color separation optical system 30, a uniform illumination optical system for forming a projection image with uniform brightness, A polarization conversion optical system or the like for converting a polarized light beam into a polarized light beam having a uniform polarization direction may be provided. The uniform illumination optical system divides the light beam emitted from the light source 10 into a plurality of partial light beams, and converts the monochromatic modulation liquid crystal panels 51 and 2 described later.
It illuminates the image forming area of the color modulation liquid crystal panel 61 with uniform brightness, and can specifically be configured to include a lens array, a rod lens, and the like. The polarization conversion optical system spatially separates a non-polarized light beam emitted from the light source 10 into two types of polarized light beams whose polarization directions are orthogonal to each other, and rotates the polarization direction of one polarized light beam to rotate the other polarized light beam. It emits light in line with that of
And a phase difference plate or the like.

The light source 10 includes a light source lamp 11 that emits light rays radially, and a parabolic reflector 12 that substantially parallelizes the light rays emitted from the light source lamp 11 and emits the light in one direction. Note that, instead of the parabolic reflector, an elliptical reflector or a spherical reflector can be used.

The color separation optical system 30 includes a dichroic mirror 31R serving as a first color separation optical element, a dichroic mirror 31G and a dichroic mirror 31B serving as a second color separation optical element, and a dichroic mirror 31.
A folding mirror 33 is provided to bend the optical path of the color light transmitted through R toward a monochromatic modulation liquid crystal panel 51 described later.

Three types of dichroic mirrors 31R, 3R
1G and 31B are mirrors having wavelength selectivity for transmitting or reflecting color light in a specific wavelength range, and are realized by forming a dielectric multilayer film on a transparent substrate such as glass. That is, the dichroic mirror 31R outputs the red light R
The dichroic mirror 31G is a mirror that reflects green light G and transmits other color light, and a dichroic mirror 31B
Is a mirror that reflects blue light B and transmits other color lights. The light beam emitted from the light source 10 is separated into red light R, green light G, and blue light B by the dichroic mirror 31R. The red light R transmitted through the dichroic mirror 31R has its optical path bent approximately 90 degrees by the folding mirror 33, and then enters a monochromatic modulation liquid crystal panel 51 described later. The green light G and blue light B reflected by the dichroic mirror 31R are separated into green light G and blue light B by the dichroic mirror 31G, and the green light G directly enters a two-color modulation liquid crystal panel 61 described later. The blue light B is incident on the same two-color modulation liquid crystal panel 61 via the dichroic mirror 31B. Since the dichroic mirror 31B does not need to separate the color light, the dichroic mirror 31B
Instead of B, a general reflection mirror may be used.

Here, two dichroic mirrors 31
G and 31B are arranged so that light beams emitted from the light source 10 enter at different angles. Specifically, Z
An imaginary axis Q is set at 45 ° to the center axis of the incident light beam on the −X plane, and the two dichroic mirrors 31G and 31B are arranged with this axis as a symmetric axis. Accordingly, the green light G and the blue light B reflected by the dichroic mirrors 31G and 31B are separated and emitted in two slightly different directions on the ZX plane.

Next, the light modulation optical system 50 is a single color modulation liquid crystal panel 51 which is a single color modulation electro optical device for modulating one type of color light, and a two color modulation electro optical device for modulating two types of color light. And a two-color modulation liquid crystal panel 61. In this embodiment, the monochromatic modulation liquid crystal panel 51 is set to modulate red light R, and the two-color modulation liquid crystal panel 61 is set to modulate green light G and blue light B. Monochromatic modulation liquid crystal panel 51
Is a transmissive liquid crystal panel that modulates incident red light R based on image information from outside (not shown) and emits a modulated light beam from the side opposite to the incident side. As shown in FIGS. 2 and 3, the monochromatic modulation liquid crystal panel 51 includes two transparent substrates (counter substrate 511, TF) made of glass or the like.
Twisted nematic (TN) between T substrates 512)
The liquid crystal 513 is sealed. On the opposite substrate 511, a common electrode 514 and a black matrix 515 for shielding unnecessary light are formed.
12, a pixel electrode 516, a thin film transistor (TFT) 517 as a switching element, and the like are formed.
When a voltage is applied to the pixel electrode 516 via 517,
The liquid crystal 513 sandwiched between the common electrode 514 is driven. Note that, on the TFT substrate 512, a plurality of scanning lines 518 and a plurality of data lines 519 are arranged so as to intersect, and in the vicinity of the intersection, a TFT 517 has a gate serving as the scanning line 518, a source serving as the data line 519, and a drain serving as the pixel electrode 516. Is connected to and arranged. And the scanning line 518
Are sequentially applied with a selection voltage, and X
The driving voltage of each pixel is written to the pixel electrode 516 via the TFT 517 of the pixel in the axial direction. The TFT 517 is turned off by the application of the non-selection voltage, and holds the applied drive voltage in a storage capacitor (not shown). The pixel electrode 516 is arranged in a region corresponding to the opening of the monochromatic modulation liquid crystal panel 51 (the opening of the black matrix 515).
7 and a pixel electrode 516 (a storage capacitor connected to the pixel electrode if necessary) constitutes each pixel. The liquid crystal 513 is not limited to the TN type, but may be a ferroelectric type or an antiferroelectric type.
Various types such as a horizontal alignment type and a vertical alignment type can be used.

Further, as shown in FIG.
A microlens array 531 for condensing the red light R separated by the dichroic mirror 31R on the pixel electrode 516 is provided on the light incident side. The microlens array 531 includes a plurality of unit microlenses 531A configured in a matrix, a mosaic, or the like. The unit microlens 531A is formed on the glass plate by etching or the like, and is bonded to the opposite substrate 511 via a resin layer (adhesive) 532 having a different refractive index from the glass plate on which the microlens array is formed. .
The lens pitch of the unit microlens 531A (the convex portion or the concave portion of the lens) is set to be the same as the pixel pitch of the pixel electrode 516. Then, as shown in FIG.
Light emission side of T substrate 512 and micro lens array 5
31 on the light incident side, respectively.
Is provided.

The two-color modulation liquid crystal panel 61 also has a structure similar to that of the above-described single-color modulation liquid crystal panel 51, and is shown in FIGS.
As shown in the figure, the opposite substrate 611, the TFT substrate 612, the liquid crystal 613, the common electrode 614, the black matrix 61
5, TFT 617, scanning line 618, and data line 61
9 is different from the pixel electrode 516 of the monochromatic modulation liquid crystal panel 51 in the size and shape of the sub-pixel electrodes 616G and 616B. That is, 1 in the monochromatic modulation liquid crystal panel 51
For two pixel electrodes 516, the two-color modulation liquid crystal panel 61
In this configuration, two sub-pixel electrodes 616G that modulate green light G and a sub-pixel electrode 616B that modulates blue light B are paired and correspond to each other. Where 2
The direction in which the two sub-pixel electrodes 616G and 616B are aligned is X
This is the axial direction, the direction in which the scanning lines 618 are arranged, and the direction in which the color light is separated by the dichroic mirrors 31G, 31B. Therefore, the sub-pixel electrodes 616G, 616B
Is the same as the length of the pixel electrode 516, but the width in the X-axis direction is set to approximately の of the width of the pixel electrode 516. As a result, the total number of pixels of the two-color modulation liquid crystal panel 61 is twice the total number of pixels of the single-color modulation liquid crystal panel 51.

As shown in FIG. 5, the light incident side of the opposite substrate 611 of the two-color modulation liquid crystal panel 61 is also provided.
Similarly to the monochromatic modulation liquid crystal panel 51, the microlens array 6 composed of a plurality of unit microlenses 631A
31 are arranged via the resin layer 632. However, unlike the case of the monochromatic modulation liquid crystal panel 51, one unit microlens 631A is configured to correspond to a pair of sub-pixel electrodes 616B and 616G arranged in the X-axis direction. Accordingly, the width of the unit microlens 631A in the X-axis direction is equal to the sum of the width of the sub-pixel electrode 616B and the width of the sub-pixel electrode 616G, and the length in the Y-axis direction is equal to that of the sub-pixel electrodes 616B and 616G. equal. The light incident side of the microlens array and the TFT
Polarizing plates 642 and 641 are provided on the light emission side of the substrate 612.

As shown in FIGS. 1 and 5, the green light G and the blue light B separated by the dichroic mirror 31R serving as the first color separation optical element are combined with the dichroic mirror 31G forming the second color separation optical element. After being reflected by 31B, it is incident on each unit microlens 631A of the microlens array 631 at a different angle. The green light G and the blue light B incident on each unit microlens 631A
Are unit microlenses 631A at different angles.
And a pair of sub-pixel electrodes 61 that are emitted from the
In the vicinity of 6B and 616G, the light is condensed separately for each color light. After the green light G and the blue light B are modulated by the respective sub-pixel electrodes 616B and 616G, the directions perpendicular to the light-incident end face of the two-color modulation liquid crystal panel 61 (the normal direction of the image forming area 61A, Z (Axial direction).

In such a monochromatic modulation liquid crystal panel 51 and a two-color modulation liquid crystal panel 61, as shown in FIG.
An image forming area 51A of the monochromatic modulation liquid crystal panel 51 configured by arranging a plurality of pixel electrodes 516;
The image forming area 61A of the two-color modulation liquid crystal panel 61 configured by arranging a plurality of 6B and 616G has the same shape and the same area. Further, as described above, the pixel electrode 516 includes the sub-pixel electrode 616B and the sub-pixel electrode 6
16G corresponds to a pair of two units. Further, in the image forming area 61A, the arrangement of the two types of sub-pixel electrodes 616B and 616G is exchanged for each column, and for example, the upper and lower positions and the left and right positions adjacent to the sub-pixel electrode 616B into which the blue light B is incident are located. , And a sub-pixel electrode 616G on which green light G is incident.

As shown in FIG. 1, the color synthesizing optical system 70 includes a dichroic prism 71, and synthesizes three kinds of modulated color lights emitted from the monochromatic modulation liquid crystal panel 51 and the two-color modulation liquid crystal panel 61. To form a color image. The dichroic prism 71 has a cubic shape, and a dielectric multilayer film 711 that transmits red light R and reflects green light G and blue light B is formed at a diagonal portion of a square in a plan view. Then, the color image synthesized by the color synthesis optical system 70 is emitted from the projection lens 90 and is enlarged and projected on a screen. The color combining optical system 70 can be configured by using a dichroic mirror instead of the dichroic prism 71. However, when a plate-like dichroic mirror is used, there is a problem that the mirror which is a light flux combining surface is likely to be warped, and as a result, a projected image is likely to be distorted. Therefore, the dichroic prism 71 that does not easily generate warpage on the light beam combining surface.
Is superior in that a high-quality projected image can be formed.

According to the first embodiment, the following effects can be obtained. Since the light modulation optical system 50 includes the monochromatic modulation liquid crystal panel 51 and the two-color modulation liquid crystal panel 61, it is easy to set optical characteristics such as brightness and color balance to a desired state, and the projection lens It is not necessary to use an expensive lens as 90, and it is easy to reduce the cost. That is, when the size of the electro-optical device is the same, when the two-color modulation liquid crystal panel 61 is used, the sub-pixel electrode 616 is used as compared with the conventional three-color modulation liquid crystal panel.
The size of G, 616B in the X-axis direction (direction in which incident color light is separated) can be increased. When the size of the sub-pixel electrodes 616G and 616B is increased, the focal length of the unit microlens 631A disposed in the preceding stage can be set relatively long, so that the condensing angle by the microlens can be reduced, and the two colors can be reduced. Modulation liquid crystal panel 61
The divergence angle α1 of the light beam emitted from the lens can be reduced (α1 <α0). Further, since two types of color light are incident on the two-color modulation liquid crystal panel 61 with respect to the conventional three-color modulation liquid crystal panel, the direction is separated by the second color separation optical element of the color separation optical system 30, and the two-color modulation is performed. The incident angle β1 of each color light incident on the liquid crystal panel 61 from different directions can also be reduced (β1 <β0). Therefore, for a spatial color separation type projector using a conventional three-color modulation liquid crystal panel,
In the spatial color separation type projector using the two-color modulation liquid crystal panel of the present invention, the divergence angle of the divergent light emitted from the light modulation optical system can be reduced (α1 + β1 <α0 + β0).
Even when the light modulation optical system (electro-optical device) is to be refined, a bright and excellent color balance can be obtained without using an expensive projection lens having a small F-number and a large aperture, without reducing the light use efficiency. A color image can be projected and displayed. Conversely, if the divergence angle (α1 + β1) of the divergent light emitted from the two-color modulation liquid crystal panel 61 is set to be the same as in the case of the three-color modulation liquid crystal panel, the focal length of the microlens is made shorter and the sub-pixel electrode 616B , 616G can be made smaller in diameter, so that the efficiency of color light incidence on the sub-pixel electrode can be increased, and the color mixing caused by the incidence of unnecessary color light on other adjacent sub-pixel electrodes can be improved. By preventing the occurrence, a color image excellent in color expression can be projected and displayed.

Further, since the dimensions of the sub-pixel electrodes 616G and 616B are larger in the two-color modulation liquid crystal panel than in the three-color modulation liquid crystal panel, the relative positional accuracy between the illumination optical system including the light source, the projection lens, and the like is high. The need to secure
The manufacture of the projector is facilitated accordingly. In the spatial color separation type projector of the present invention, two liquid crystal panels 5
Since the projector can be composed of the projectors 1 and 61, the cost and the size can be reduced as compared with the three-plate type projector.

Further, since the area of the pixel electrode 516 of the single-color modulation liquid crystal panel 51 is set to be approximately twice the area of the sub-pixel electrodes 616G and 616B of the two-color modulation liquid crystal panel 61, each of the liquid crystal panels 51 and 61 is formed. Image forming area 51
A, 61A can have the same number of pixels,
A projection image with excellent brightness and color balance can be realized.

Further, since the red light R is modulated by the monochromatic modulation liquid crystal panel 51 having a large area per pixel, the light source lamp having a short arc length (for example, ultra high pressure mercury) in which the intensity of the red light R is relatively small. Lamps and metal halide lamps)
When the light source is used as the light source, the red light R can be used without waste. As a result, it is easy to balance the intensity with other color lights, and it is possible to realize a projected image having an excellent color balance without lowering the light use efficiency.

Further, since the unit microlenses 531A corresponding to the respective pixel electrodes 516 are arranged on the light incident side of the image forming area 51A of the monochromatic modulation liquid crystal panel 51, the light use efficiency of the red light R is further improved. Thus, it is possible to realize a brighter projected image having an excellent color balance.

Further, since the dichroic mirrors 31R, 31G and 31B are employed as the color separation optical system 30, it is easy to reduce the weight and cost of the projector. In the use of the dichroic mirror, there is a problem that the optical path is easily shifted due to the warpage of the mirror. However, since the color separation optical system 30 is disposed on the illumination system side including the light source 10, high accuracy is required. Not a problem. Further, since the dichroic prism 71 is employed as the color synthesizing optical system 70, no warpage occurs in the dielectric multilayer film 711, and no optical path shift occurs unlike the dichroic mirror. Can be performed with high accuracy, and a high-quality projected image can be displayed.

2. Second Embodiment Next, a second embodiment of the present invention will be described. In the following description, the same portions as those already described are denoted by the same reference numerals, and description thereof will be omitted or simplified. In the first embodiment, the total number of pixels of the monochromatic modulation liquid crystal panel 51 is １ ／ of the total number of pixels of the two-color modulation liquid crystal panel 61.
Therefore, the pixel electrode 516 of the monochromatic modulation liquid crystal panel 51
Area of the sub-pixel electrode 61 of the two-color modulation liquid crystal panel 61
The area was set to be approximately twice the area of 6B and 616R.

On the other hand, in the present embodiment, as shown in FIGS. 7 and 8, the total number of pixels of the single-color modulation liquid crystal panel 81 is equal to the total number of pixels of the two-color modulation liquid crystal panel 61. The difference is that the area and shape of the pixel electrode 816 of the liquid crystal panel 81 are set to be substantially the same as the area and shape of the sub-pixel electrodes 616B and 616R of the two-color modulation liquid crystal panel 61. Further, in the first embodiment, the monochromatic modulation liquid crystal panel 51 modulates the red light R, but in the present embodiment, the monochromatic modulation liquid crystal panel 81 modulates the green light G. The two-color modulation liquid crystal panel 6
1 has the same structure as that of the first embodiment, but modulates blue light B and red light R different from those of the first embodiment.
Only the sign of the sub-pixel electrode is 616B or 61 corresponding to the color light.
The reference numeral 6R is used, and the same reference numerals as those in the first embodiment are used for other portions (see FIG. 8).

The projector according to the present embodiment has the same basic structure as the projector according to the first embodiment (see FIG. 1), and a dichroic mirror 31R that transmits red light R as a first color separation optical element is replaced with a green light. A dichroic mirror that transmits light G is changed, and a dichroic mirror 31G that constitutes the second color separation optical element is changed to a dichroic mirror that reflects red light R.

The monochromatic modulation liquid crystal panel 81 according to the present embodiment
As shown in FIG. 7, the pixel electrode 816 has a width dimension that is substantially half of the pixel electrode 516 in the first embodiment (the length dimension is the same, see FIG. 3). Unit microlens 831A of microlens array 831 provided on the light incident side of counter substrate 511
The size has also been changed. That is, the lens pitch of the unit microlenses 831A in the X-axis direction and the Y-axis direction is set to be equal to the pitch of the pixel electrodes 816 in the corresponding direction of the pixel electrodes 816.

In the present embodiment, as shown in FIG. 8, the single-color modulation liquid crystal panel 81 and the two-color modulation liquid crystal panel 61 are composed of image forming regions 61A and 81 having the same area.
Because of having A, the number of pixels that modulate green light G in the monochromatic modulation liquid crystal panel 81 is twice the number of pixels that modulate red light R or blue light B in the two-color modulation liquid crystal panel 61. Then, each pixel electrode 816 of the monochromatic modulation liquid crystal panel 81 and sub-pixel electrodes 616B,
As shown in FIG. 8, the correspondence of 16R is １ ／ in the X-axis direction.
It is set so that a shift by a pixel occurs.

According to the second embodiment, the following effects are obtained in addition to the effects described in the first embodiment. That is, considering that the viewer's perception of the resolution is likely to be affected by the resolution of the green light G in terms of human visual characteristics, in the projector of the present embodiment, the resolution of the green light G modulated by the monochromatic modulation liquid crystal panel 81 is considered. However, since the resolution of the red light R or the blue light B modulated by the two-color modulation liquid crystal panel 61 is twice as high, a higher resolution projection image can be displayed.

The pixel array of the image forming area 61A of the two-color modulation liquid crystal panel 61 and the pixel array of the image forming area 81A of the monochromatic modulation liquid crystal panel 81 are separated in the X-axis direction (the direction in which the scanning lines are arranged, the color light is separated). Of the liquid crystal panels 61 and 81
In the color projection image obtained by combining the luminous fluxes emitted from the pixels, the pixel structures arranged in a plane can be made inconspicuous, and a high-quality projection image with improved visibility of the projection image can be realized. In addition, since the pixels are shifted in the direction in which the scanning lines are arranged (the X-axis direction), the pixel structure can be made more inconspicuous from human visual characteristics.

The present invention is not limited to the above-described embodiments, but includes the following modifications. In each of the above embodiments, the present invention is applied to the projector using the transmissive liquid crystal panel. However, the present invention is not limited to this. Further, although the liquid crystal panels 51 and 61 using TFTs as switching elements have been adopted as the electro-optical device, the invention is not limited to this. That is, the same liquid crystal panel may be one using a TFD (thin film diode) as a switching element. Moreover,
Even if a PDLC (polymer dispersed liquid crystal) panel is used, it is possible to construct a projector that can expect the same effect,
In short, the present invention can be applied to various projectors having an electro-optical device of a type that modulates a light beam emitted from a light source. In each of the above embodiments, the pixel arrangement of the two-color modulation liquid crystal panel 61 is set in a matrix. However, the present invention is not limited to this, and various pixel arrangements such as a stripe type and a triangle type may be adopted.

Further, in the first embodiment, the dichroic mirror 31R transmitting the red light R is employed as the first color separation optical element, but the present invention is not limited to this. That is, the color light separated by the first color separation optical element is a light source,
What is necessary is just to set suitably according to the characteristic of an electro-optical device and a color synthesis optical system. For example, when a halogen lamp, a xenon lamp, and a certain metal halide lamp or the like having a small relative intensity of blue light B are used as a light source lamp,
It is effective to adopt a configuration in which blue light B is incident on the monochromatic modulation liquid crystal panel because both light use efficiency and color balance can be achieved.

In each of the above two embodiments, the microlens array is arranged in each of the monochromatic modulation liquid crystal panels 51 and 81, but these microlenses are arranged in the monochromatic modulation liquid crystal panels 51 and 81. Are arranged for the purpose of improving the light use efficiency in the case where the light intensity of the color light incident on the monochromatic modulation liquid crystal panels 51 and 81 is sufficiently large. Therefore, the cost of the optical system can be reduced accordingly. In addition, specific structures, shapes, and the like at the time of carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

[0051]

According to the projector according to the present invention as described above, since the light modulation optical system includes the two-color modulation electro-optical device, the light modulation optical system is compared with the conventional projector including the three-color modulation electro-optical device. (2) The size of the pixels constituting the image forming area of the two-color modulation electro-optical device can be increased. Accordingly, the converging angle α of the microlens disposed in front of the two-color modulation electro-optical device and the angle β for separating the color light in the direction can be reduced, so that the optical characteristics such as brightness and color balance can be changed to a desired state. It is not necessary to use a large and expensive projection lens, and it is possible to realize a projector that can be easily reduced in cost.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a structure of a projector according to a first embodiment of the invention.

FIG. 2 is a perspective view illustrating a structure of a monochromatic modulation electro-optical device according to the embodiment.

FIG. 3 is a sectional view illustrating a structure of a monochromatic modulation electro-optical device according to the embodiment.

FIG. 4 is a perspective view illustrating a structure of a two-color modulation electro-optical device according to the embodiment.

FIG. 5 is a sectional view illustrating a structure of a two-color modulation electro-optical device according to the embodiment.

FIG. 6 is a schematic diagram illustrating a correspondence between pixel arrangements of the monochromatic modulation electro-optical device and the two-color modulation electro-optical device in the embodiment.

FIG. 7 is a cross-sectional view illustrating a structure of a monochromatic modulation electro-optical device included in a projector according to a second embodiment of the invention.

FIG. 8 is a schematic diagram illustrating correspondence between pixel arrangements of the monochromatic modulation electro-optical device and the two-color modulation electro-optical device in the embodiment.

FIG. 9 is a schematic diagram of a main part showing a structure of a conventional projector.

FIG. 10 is a cross-sectional view illustrating a structure of an electro-optical device used for a conventional projector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Light source 30 Color separation optical system 50 Light modulation optical system 70 Color synthesis optical system 51, 81 Monochromatic modulation electro-optical device 61 Two-color modulation electro-optical device 51A, 61A, 81A Image formation area R Red light G Green light B Blue light 531A , 631A, 831A Unit micro lens

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI G09F 9/00 360 G09F 9/00 360Z H04N 9/31 H04N 9/31 C (58) Fields surveyed (Int. Cl. ⁷ , DB name) G03B 33/12 G02F 1/13 505 G02F 1/1335 G02F 1/1343 G03B 21/00 G09F 9/00 360 H04N 9/31

Claims (8)

(57) [Claims] 1. A light source, a first color separation optical element for separating a light beam emitted from the light source into two types of color light of a first color light and another color light, and separated by the first color separation optical element The second color light is further separated into two types of color light, a second color light and a third color light.
A first mirror that reflects the second color light and transmits the third color light, and a second mirror that reflects the third color light transmitted through the first mirror. A color separation optical system comprising: a second color separation optical element comprising: a plurality of pixel electrodes; and a monochromatic modulation electro-optical device that receives the first color light from the first color separation optical element. A microlens for receiving the second and third color lights from the second color separation optical element, and a plurality of sub-pixel electrodes corresponding to each of the second and third color lights; A two-color modulation electro-optical device, wherein the lens is provided at a ratio of one to two of the sub-pixel electrode for the second color light and the sub-pixel electrode for the third color light; Monochromatic modulation electro-optic device and the two-color modulation electro-optic A color synthesizing optical system for synthesizing each color light modulated by the device, wherein three axes orthogonal to each other are set as an X-axis, a Y-axis, and a Z-axis, a light traveling direction is a Z-axis direction, When the direction in which the color light is separated by the system is the X-axis direction, the area of the pixel electrode of the monochromatic modulation electro-optical device and the dimension in the X-axis direction are the area of the pixel electrode of the two-color modulation electro-optical device. And the dimension in the Y-axis direction of the pixel electrode of the single-color modulation electro-optical device is set to substantially twice the dimension in the X-axis direction.
A projector characterized in that the dimension is substantially the same as the dimension in the axial direction. 2. A light source, a first color separation optical element that separates a light beam emitted from the light source into two types of color light, a first color light and another color light, and separated by the first color separation optical element. The second color light is further separated into two types of color light, a second color light and a third color light.
A first mirror that reflects the second color light and transmits the third color light, and a second mirror that reflects the third color light transmitted through the first mirror. A color separation optical system comprising: a second color separation optical element comprising: a plurality of pixel electrodes; and a monochromatic modulation electro-optical device that receives the first color light from the first color separation optical element. A microlens for receiving the second and third color lights from the second color separation optical element, and a plurality of sub-pixel electrodes corresponding to each of the second and third color lights; A two-color modulation electro-optical device, wherein the lens is provided at a ratio of one to two of the sub-pixel electrode for the second color light and the sub-pixel electrode for the third color light; Monochromatic modulation electro-optic device and the two-color modulation electro-optic A color synthesizing optical system for synthesizing each color light modulated by the device, wherein three axes orthogonal to each other are set as an X-axis, a Y-axis, and a Z-axis, a light traveling direction is a Z-axis direction, When the direction in which the color light is separated by the system is the X-axis direction, the area of the pixel electrode of the monochromatic modulation electro-optical device and the dimensions in the X-axis and Y-axis directions are the same as those of the sub-color modulation electro-optical device. A projector characterized by having substantially the same area as the pixel electrode and dimensions in the X-axis and Y-axis directions. 3. The projector according to claim 2, wherein the arrangement of the pixel electrodes of the monochromatic modulation electro-optical device is equal to the arrangement of the sub-pixel electrodes of the two-color modulation electro-optical device.
/ 2 pixels corresponding to a position shifted by two pixels. 4. The projector according to claim 3, wherein an arrangement of the pixel electrodes of the monochromatic modulation electro-optical device is shifted from an arrangement of the sub-pixel electrodes of the two-color modulation electro-optical device in the X-axis direction. Projector. 5. The projector according to claim 1, wherein the monochromatic modulation electro-optical device further includes a plurality of microlenses for receiving the first color light from the first color separation optical element. A projector, wherein the microlens is provided at one ratio with respect to one pixel electrode of the monochromatic modulation electro-optical device. 6. The projector according to claim 1, wherein the monochromatic modulation electro-optical device modulates green light. 7. The projector according to claim 1, wherein the monochromatic modulation electro-optical device modulates red light. 8. The projector according to claim 1, wherein the monochromatic modulation electro-optical device modulates blue light.