JP3236195B2 - Optical modulation device and color image display device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical modulator and a color image display using the optical modulator.

[0002]

2. Description of the Related Art Conventionally, in a single-panel color optical modulator using a liquid crystal optical modulator, the area of a black matrix that shields the wiring of an optical modulation controlled part around the liquid crystal optical modulator occupies the liquid crystal optical modulator. The ratio is high, which is a factor that further reduces the light use efficiency of the entire device.

In order to solve this problem, a micro lens array 2 as shown in FIG.
There is known a method of improving the light use efficiency of the optical modulation device 200 by arranging the illumination light from a white light source on each pixel of the optical modulation element 201 by disposing the illumination light from the white light source on the front surface of the 1R, 51G, and 51B. Here, 3 in FIG. 38 is a transparent substrate, and 5 is a black matrix.

[0004]

In the above-mentioned conventional example, a color filter is used as a member for extracting color light corresponding to each optical modulation element from white light. However, since the color filter transmits only light of a certain wavelength component among white light incident on each pixel, light of other wavelength components is wasted, and the light use efficiency is extremely low.

SUMMARY OF THE INVENTION An object of the present invention is to realize a single-plate color optical modulation device having a small light quantity loss.

[0006]

According to the first aspect of the present invention, there is provided an optical conversion device comprising:
The modulator adjusts the luminous flux of the wide wavelength band to different wavelength bands
A diffraction grating for decomposing the light into a plurality of light beams, and light in each of the wavelength bands.
Optics that modulates the bundle for each pixel and reflects it with a reflector
An optical modulator comprising a modulation element,
The element is a one-dimensional binary diffraction grating;
Is modulated by the optical modulator and reflected before
The light flux of each wavelength band is synthesized, and the optical modulation element and the
Characterized by being integrally formed with the diffraction grating
I have. The optical modulator according to the invention of claim 2 is according to claim 1.
Wherein the diffraction grating has a wide wavelength in a unit area.
The direction of decomposing the luminous flux in the band is different, and the light is emitted in different directions
Of the optical modulation element into which the light beam of the same wavelength band
It is characterized by having a common pixel. Claim 3
The optical modulator according to the present invention is according to claim 2 and has the following features.
The luminous flux emitted from the common pixel is a plurality of light beams of the diffraction grating.
In the unit area.

According to a fourth aspect of the present invention, there is provided an optical modulator having a wide wavelength.
Decomposes the luminous flux of the band into multiple luminous fluxes with different wavelength bands
Diffraction grating, and a light flux decomposed into the predetermined wavelength band
Modulation that reflects light by a reflector while modulating light for each pixel
An element and the diffraction grating is reflected by the reflection plate.
An optical modulator for synthesizing the divided light flux,
The grating is the direction in which the broad-band light flux is decomposed into unit areas.
Are different, and the luminous flux of the same wavelength band emitted in different directions
A common pixel of the optical modulation element to be incident;
The light beam emitted from the pixel of a plurality of units of the diffraction grating
It is characterized by being incident on a region. The invention of claim 5
Optical modulator modulates incident light for each pixel and emits it
An optical modulator, and a light incident side of the optical modulator.
A first diffraction grating for decomposing light into a predetermined wavelength band;
Decomposed into a predetermined wavelength band on the light emission side of the optical modulation element
And a second diffraction grating for combining the incident light.
The luminous flux decomposed by the diffraction grating of the predetermined wavelength band
At a different pixel of the optical modulation element, the pixel
An optical modulator that modulates the light beam by
The first diffraction grating emits light of the wide wavelength band for each unit area.
Same direction emitted in different directions to disassemble bundle
A common image of the optical modulation element on which a light beam in a wavelength band is incident.
Element, and the second diffraction grating combines light beams in a unit area.
Direction of light emitted from the common pixel
Are incident on different unit areas of the second diffraction grating.
It is characterized by. The optical modulator according to claim 6 is
It is according to any one of claims 1 to 5, wherein the
Luminous flux in a wide wavelength band, or decomposed into the predetermined wavelength band
Condensed light into each pixel of the optical modulation element
It is characterized by having a condensing means for making light incident.

The optical modulator according to the fourth aspect of the present invention has a wide band.
A light-condensing element group for converting the light into a plurality of convergent light fluxes;
Decomposes a number of convergent light beams into light beams of three colors, R, G, and B, respectively
A plurality of diffraction gratings for modulating the light beams of the three colors R, G, and B;
A pixel and a reflector for reflecting the light beams of the three colors R, G and B.
An optical modulation element, wherein the diffraction grating has the optical modulation element.
The light beams of the three colors R, G, and B modulated and reflected by the tuning element
An optical modulator for synthesizing, wherein the diffraction grating is one-dimensional.
A binary diffraction grating, wherein the diffraction grating is
A color corresponding to each of the plurality of luminous fluxes from the optical element group
Having a separation area, and a color separation direction among the plurality of color separation areas.
The color separation areas adjacent to each other correspond to the luminous flux of the G color.
The separation directions of the R and B color light beams are opposite to each other.
The G at a position corresponding to the center of the color separation area.
There is a color pixel, and the boundary between the adjacent color separation areas
At the position corresponding to the pixel of the color R or the image of the color B
And the luminous flux of G color from the color separation area is
The same before entering the color pixel and reflecting on the reflector
Incident on the color separation area and that of the adjacent color separation area
The R luminous flux from each of them enters the common R pixel.
And then reflected by the reflector to produce the next color component
Incident on the solution area, each of the adjacent color separation areas
These B light beams are incident on the B pixel common to each other.
And the adjacent color separation area is reflected by the reflection plate.
It is characterized by being incident on the region . An optical modulator according to a fifth aspect of the present invention converts broadband light into a plurality of convergent light beams.
And a plurality of converging light fluxes R, G, B, respectively.
A first diffraction grating for decomposing the light into three color light beams;
Modulator having a plurality of pixels for modulating light beams of three colors
And three colors of R, G, and B modulated by the optical modulator.
Optical modulator having a second diffraction grating for synthesizing light beams
And wherein the first diffraction grating is a one-dimensional binary type.
A diffraction grating, wherein the first diffraction grating is the light-collecting element
Color components corresponding to each of the plurality of convergent light beams from the group
A plurality of color separation regions of the first diffraction grating, each having a solution region;
Of the color separation areas adjacent to each other in the color separation direction
The light flux of the R color and the light flux of the B color with respect to the light flux of the color
Are separated from each other, and the optical modulation element is
A pixel of G color is placed at a position corresponding to the center of the color separation area.
Corresponding to the boundary between the adjacent color separation areas.
Located has a color of a pixel of a color of a pixel or B of R, the color separation
The light flux of the G color from the solution area is incident on the pixel of the G color
And from each of the two adjacent color separation areas
The luminous flux of the R color is incident on the common R pixel, and
Of the B color from each of two adjacent color separation areas
The light flux is incident on the B pixel common to each other, and the second
The diffraction grating is the plurality of color separation regions of the first diffraction grating.
Has a color combining region at positions corresponding to each of the color
In the combining area, the G color emitted from the G color pixel
The light flux and the pixel of G color are sandwiched in the color separation direction.
From the pixel of the R color and the pixel of the B color
The emitted light beam of the R color and the light beam of the B color are incident
It is characterized by being synthesized . An optical modulator according to a sixth aspect of the present invention is the optical modulator according to any one of the first to third aspects, wherein the optical beam is collected by condensing the light beam in the wide wavelength band or the light beam decomposed into the predetermined wavelength band. It is characterized in that it has a condensing means for making convergent light incident on each pixel of the modulation element.

The optical modulator according to the invention of claim 7 is claim 4.
7. The method according to claim 6 , wherein the condensing unit and the unit region of the diffraction grating or the first diffraction grating are paired. An optical modulator according to an eighth aspect of the present invention is the optical modulator according to any one of the first to seventh aspects, wherein a color filter is provided at a position where a light beam is decomposed into a predetermined wavelength band by the diffraction grating or the first diffraction grating. It is characterized by having. An optical modulator according to a ninth aspect of the present invention is the optical modulator according to any one of the first to eighth aspects, wherein the optical modulation element is a polymer-dispersed liquid crystal.

[0010]

FIG. 1 is a cross-sectional view (a cross section parallel to the optical axis of the optical modulator) of an optical modulator that best illustrates the features of the present invention.

In FIG. 1, reference numeral 1 denotes an optical modulation element group including an optical modulation control section (not shown) and an optical modulation control section. In the present embodiment, a polymer-dispersed liquid crystal is used for the optical modulation controlled part. Reference numeral 2 denotes a light-collecting element group for condensing incident light, 3 denotes a transparent substrate that sandwiches the optical modulation element 1, and 4 denotes a light-shielding film that shields light unnecessary for image display. Numeral 6 is provided one-to-one with respect to the light-collecting element group 2, decomposes the light condensed by the light-collecting element group 2 into a plurality of color lights, and combines and emits the color lights reflected from the optical modulation element group 1. Color separation / synthesis element group. Reference numeral 7 denotes a reflection plate provided between the optical modulation element group 1 and the transparent substrate 3.

In the figure, R (red) and G of the optical modulation element group 1 are shown.
The symbols of (green) and B (blue) represent the wavelength bands of light incident and reflected by the respective optical modulation elements.

In FIG. 1, arbitrary light-collecting elements are denoted by A0, A
The condensing elements adjacent to 0 are T + 1, T-1, and the optical modulating elements including the optical axes of A + 1, A-1, and A0 (the center lines of the condensed light flux) are T0 and T0.
Let the optical modulating elements adjacent to the optical separation element be T + 1, T-1, and S0, and the color separation and synthesis elements adjacent to S0 be S + 1 and S-1, respectively. After passing through the color separation / combination element S0, the white light flux condensed at A0 is color-separated into three color lights in the RGB band, and the optical modulation elements T0, T + 1, and T−.
1 and is reflected by the reflector 7. The light beams in the respective wavelength bands undergo optical modulation until they are emitted from the optical modulation elements T0, T + 1, and T-1. The light in the G wavelength band modulated by the optical modulation element T0 is separated by the color separation / combination element S + 1, and is modulated in the R wavelength band by the optical modulation element T + 1.
The light in the wavelength band of B decomposed by 1 and modulated by the optical modulation element T-1 is combined with the light in the optical modulation element S0.

The principle of optical modulation by polymer-dispersed liquid crystal is generally known, and a description thereof will be omitted.

Next, an example of a method of driving an image signal in a liquid crystal panel according to the present embodiment will be briefly described.

When the input image is a video signal, the image signal for one frame of the image to be displayed is temporarily stored in a memory, and then the order is sequentially changed so as to correspond to the pixel arrangement of the panel, and sampling is performed. In the case of an input image already stored in a memory such as a data signal of a personal computer or the like, it can be handled by changing the sampling method. However, in this embodiment, since panel pixels of each color are different in each line, an image signal corresponding to color light having a small number of pixels is obtained by averaging two pixels of the original image signal into one pixel. Processing must be performed before sampling.

Next, the color separation / synthesis element group 6 will be described with reference to FIG.
This will be described with reference to an enlarged sectional view of FIG.

In this embodiment, the color separation / synthesis element group 6
Is a one-dimensional binary diffraction grating formed of resin. The one-dimensional binary diffraction grating is formed by forming a diffraction grating in a stepwise manner as shown in FIG. 2, and is formed so that the deflection angles of the diffracted light are all the same. In the present embodiment, the step widths L1, L
2 and L3. It should be noted that if the number of steps is three or more, the same effect can be obtained regardless of whether the number of steps is four or five. A transmission type diffraction grating as shown in this embodiment is disclosed in Applied Optics, Vol.
As disclosed in No. 5, No. 2273 to No. 2279 (No. 19788.1), an incident light beam incident on a diffraction grating is transmitted and diffracted and separated mainly into three directions. This diffraction grating
For example, when the blazed wavelength is λ0, the required grating thickness Dt for the blazed wavelength λ0 is Dt = m · λ0 / (nλ0-1). Here, nλ0 is the refractive index of the medium. m, λ
0 is m = 2, λ0 = 530 nm, and the refractive index nλ0 =
When calculated as about 1.5, the lattice thickness is Dt = 212.
It is about 0 nm.

In this embodiment, the color separation / combination elements adjacent to each other in the diffraction direction of the incident light are configured so that the wavelength bands of the +1 order light and the −1 order light are reversed. Thus, the same color light is incident on each pixel of the optical modulation element 1.

The color separation has been described above, but the effect of combining the three color lights by reversing the path of the light beam will be described.

FIG. 3 is a schematic diagram of a reflection type color image display device using the optical modulation device 10. As shown in FIG.

In FIG. 3, reference numeral 10 denotes an optical modulator according to the present invention;
1 is a white light source placed at the focal position of the parabolic mirror 12, 13 is a condenser lens, 14 is a projection lens, 15 is a projection lens aperture, 16 is a projection screen, 17 is a condenser lens, 1
Reference numeral 8 denotes a mirror provided on the white light source 11 side of the projection lens stop 15.

The light emitted from the white light source 11 is a parabolic mirror 12
Is converted into substantially parallel light by the condenser lens 17, the mirror 18,
The light enters the optical modulation device 10 via the condenser lens 13. The light to which image information for each of the RGB color lights is given by the optical modulation device 10 displays an image on a projection screen 16 via a condenser lens 13 and a projection lens 14.

The image information of each color light of RGB is transmitted to the optical modulator 1
0 depends on the degree of diffusion of the light beam. When a stop having an opening on the optical axis as shown in FIG. 3 is used, a light beam having a low degree of diffusion passes through the projection lens stop 15 and reaches the projection screen 16, and a light beam having a high degree of diffusion is projected on the projection lens stop. 15 does not reach the projection screen 16.
That is, in the image display device of FIG. 3, a light beam having a low degree of diffusion is used for image display. Contrary to the configuration shown in FIG. 3, when the aperture shape is such that the light beam near the optical axis is blocked, a light beam having a high degree of diffusion is used for image display.

With this configuration, the white light incident on the optical modulation device 10 is decomposed into a plurality of color lights by the color separation / synthesis element group 6 and condensed on the optical modulation elements corresponding to the respective color lights without waste. Therefore, the light use efficiency can be greatly improved. At the same time, by using the optical modulation device 10 of the present invention for a color image display device, a bright device can be provided without increasing the size of the device. In addition, since the periodic structure (RGB mosaic structure and black matrix) of the optical modulator becomes invisible on the screen and an image display in which RGB three colors are completely synthesized can be displayed, even when approaching the screen, a high-quality image can be displayed. It becomes possible to appreciate. Also,
Since an incident light beam is condensed for one pixel, a pixel having a low aperture ratio can be employed, so that there are many advantages such as an increase in manufacturing yield of the optical modulation element.

The light-collecting element may be a flat microlens. Further, it is conceivable to reverse the arrangement order of the light-collecting element and the color separation / synthesis element as shown in FIG. In FIG. 4, reference numeral 41 denotes a light collecting element group such as a flat microlens. Further, the color separation / synthesis element group may be formed integrally with the light collection element group or the transparent substrate.

In the present embodiment, the number of pitches in one element of the color separation / synthesis element is two as shown in FIG. 2, but it is necessary to change it according to the specifications of the optical modulator. Also, by slightly changing the grating thickness within one pitch of the diffraction grating for each step, and designing the diffraction grating shape such that the grating width within one pitch of the diffraction grating is unequal, the ± 1st-order diffracted light inner band is obtained. Since the components can be reduced, ideal color separation can be further achieved. Further, the reflection plate 7 may be formed simultaneously with a metal layer forming a wiring portion of the optical modulation element group 1.

Further, as shown in FIG. 5, a mode in which a color correction color filter 51 is provided at a place where each color light is separated can be considered. In this configuration, when the spectral characteristics of each color light separated by the color separation / synthesis element 6 are different from the spectral characteristics of the image signal, each color light is made incident on the color correction color filter 41 to obtain ideal color information. This enables faithful image color reproduction. In this case, the light is transmitted through the color filter 51 after being decomposed into each color light, so that the light use efficiency does not decrease so much.

As shown in FIG. 6, a light shielding wall 61 may be provided to prevent diffused light of the polymer dispersed liquid crystal from entering the adjacent elements between the optical modulation elements and causing crosstalk. Conceivable. With this configuration, it is possible to provide a color image display device with higher image quality.

The color filter 5 shown in FIG.
1. It is needless to say that the light shielding wall 61 shown in FIG.

Next, another embodiment of the optical modulation device is shown in FIG.
Shown in

In FIG. 7, components having the same reference numerals as those in FIG. . The most significant difference between the optical modulation device 20 in FIG. 7 and the optical modulation device in FIG.
This is the point used for Accordingly, the optical modulation device 20 of the present embodiment has the polarizing plate 22.

Next, FIG. 8 is a schematic diagram of a reflection type color image display device using the optical modulation device 20.

In FIG. 8, components having the same reference numerals as those in FIG. 19 is a polarizing beam splitter. The optical modulation device 20 functions as a shutter that controls the transmittance of color light having image information by using a combination of the polarizing plate 22 and the reflecting plate 7 whose light beam phase difference changes by π when reflected. However, the polarization axis of the polarizing plate 22 and the alignment direction of the liquid crystal molecules are uniquely determined, and thus the description is omitted here.

By configuring the optical modulation device in this manner, the same effect as when using the polymer-dispersed liquid crystal for the optical modulation controlled portion can be obtained, and at the same time, the use of the TN liquid crystal can provide a high contrast. An image display device can be provided.

In addition to the TN type liquid crystal, other optical modulation controlled parts such as a guest host liquid crystal may be used. Further, in FIG. 8, when the polarization separation accuracy of the polarization beam splitter 19 is not sufficient, if one polarizing plate is added between the condenser lens 13 and the polarization beam splitter 19, the contrast can be further improved.

FIGS. 9 to 13 are plan views of the optical modulation device according to the present invention as viewed from the incident side, and show the relationship between the arrangement of the light condensing element and the optical modulation element.

FIG. 9 shows an optical modulator according to the present invention.
The light incident on the optical modulation element including the optical axis of the light condensing element (the letter with an underbar in FIG. 9) is G color. The light-collecting element has a shape in which the refractive power of the lens in the direction parallel to the two sides of the optical modulation element is different from each other, and the light beam incident on the light-collecting element A0 is condensed on the color separation element S0. Since the visibility of the human eye, which is the observer, is highest in the G color band, a bright image can be viewed by arranging the condensing elements and the optical modulation elements in this manner. In FIG. 9, one element shape of the optical modulation element is a square, but may be a rectangle.

FIG. 10 shows an optical modulator according to the present invention in which the light is incident on the optical modulator including the optical axis of each of the light-collecting elements of a light-collecting element array arranged in any one-dimensional direction (horizontal direction in the figure). When the light (letters with an underbar in FIG. 10) is the same and the incident light is B color, the incident light to the light condensing element row adjacent to this light condensing element row is R color and G color, respectively. It was done. By arranging the light condensing elements and the optical modulation elements in this manner, the number of all optical modulation elements of each color becomes equal, so that it is possible to provide a display device in which the color balance can be easily adjusted.

In FIGS. 9 and 10, the two-dimensional arrangement of the optical modulation elements is arranged in a lattice, but the same effect can be obtained even in a staggered arrangement as shown in FIG.

FIG. 12 shows that all the light incident on the optical modulation element including the optical axis of the light condensing element is of G color, as in the case of FIG. Adjacent optical modulation elements in the direction perpendicular to the decomposition direction are also of the G color. By arranging the light condensing element and the optical modulation element in this way, the binary diffraction grating has a continuous shape in a one-dimensional direction, so that the formation is easy and the cost can be reduced. Further, as shown in FIG. 13, the light-collecting element can be a lenticular lens. In this case, the black matrix structure in the direction having no power of the lenticular lens cannot be removed and remains, but by changing the configuration of the black matrix while keeping the aperture ratio constant, almost the same as the example shown in FIG. Similar effects can be obtained.

FIG . 14 shows a transmission type optical modulator 30.
FIG. Components having the same reference numerals as those of the reflection-type optical modulation device 10 have the same functions, and thus description thereof will be omitted.

The difference from the reflection type optical modulator 10 is that
The point is that the light condensing element group 2 and the color separation / synthesis element group 6 are provided as a pair on the incident side and the output side. Therefore, the light-collecting element group 2 on the emission side functions as a collimating element, and the color-separation / synthesis element group 6 on the incidence side performs only color separation, and the emission side performs only color synthesis.

Next, the image forming operation of the optical modulation device 30 will be described. As in the case of FIG. 1, an arbitrary light-collecting element is A0, and light-collecting elements adjacent to A0 are A + 1, A-1, A
The optical modulation element including the optical axis of 0 (the center line of the converged light flux) is denoted by T
0, T + 1, T-1, A-1
The color separation / combination element on the incident side including the optical axis of 0 is S0, the color separation / combination element adjacent to S0 is S + 1, S-1, and the color separation / combination element on the output side including the optical axis of A0 is adjacent to M0 and M0. The light-collecting element on the emission side including the optical axes of M + 1, M-1, and A0 is C0, and the light-collecting element adjacent to C0 is C +.
1, C-1. After passing through the color separation / combination element S0, the white light beam condensed at A0 is color-separated into three color lights in the RGB band, enters the optical modulation elements T0, T + 1, and T-1 and undergoes optical modulation. The light in the G wavelength band modulated by the optical modulation element T0 is separated by the color separation / combination element S + 1 and modulated in the R wavelength band by the optical modulation element T + 1, and the light in the R wavelength band by the color separation / combination element S-1. After being decomposed and combined in the color separation / combination element M0 with the light in the B wavelength band modulated by the optical modulation element T-1,
The light is converted into substantially parallel light by the light condensing element C0 and emitted.

Next, a schematic diagram of a transmission type color image display device using the optical modulation device 30 is shown in FIG.

The light emitted from the white light source 11 is
The light is converted into substantially parallel light by 2 and enters the optical modulation device 30.
The light provided with the image information for each of the RGB color lights by the optical modulation device 30 includes the condenser lens 13 and the projection lens 1.
An image is displayed on the projection screen 16 via the display 4.

The image information of each color light of RGB is transmitted to the optical modulator 3.
0 depends on the degree of diffusion of the light beam. In the case of using a stop having an aperture on the optical axis as shown in FIG. 15, a light beam having a low degree of diffusion passes through the projection lens stop 15 and reaches the projection screen 16, while a light beam having a high degree of diffusion is projected on the projection lens stop. 15 does not reach the projection screen 16. That is, in the image display device of FIG. 15, a light beam having a low degree of diffusion is used for image display. Contrary to the configuration shown in FIG. 15, when the aperture shape is to block the light beam near the optical axis, a light beam having a high degree of diffusion is used for image display.

FIG. 16 shows a configuration in which a color correction color filter 51 is provided at a place where each color light is separated in the optical modulator of FIG. 14, and FIG. 17 shows each optical modulator of the optical modulator of FIG. A light shielding wall 61 is provided between them. By configuring the optical modulation device in this manner, it is possible to provide an image display device with high image quality. Incidentally, the position of the color correction color filter 51 may be on the front surface of the optical modulation element group 1.

With this configuration, the same effect as that of the reflection type can be obtained even in the transmission type color image display device.

FIG. 15 illustrates a color image display device using only one optical modulation device 30. However, in order to display a brighter image, the light source 11, the parabolic mirror 12, the condenser lens 17, the optical modulation device 20 There is also an example in which images are completely synthesized by using two sets of illumination / optical modulation units composed of. This example is shown in FIG.

With this configuration, it is possible to provide a device that requires a brighter image display for business use or the like with a simple device configuration.

As the optical modulation controlled portion, not only a polymer dispersed liquid crystal but also a TN liquid crystal can be used. The structure is shown in FIG.
Shown in In FIG. 19, reference numeral 21 denotes an optical modulation element using a TN type liquid crystal as an optical modulation controlled part, and reference numerals 22 and 23 denote polarizing plates having polarization axes orthogonal to each other.

FIG. 20 is a schematic diagram of a color image display device using this optical modulation device. The optical system of the color image display device in FIG. 20 is generally called a Koehler illumination system, and is known as an optical system that forms an image of a light source on a pupil of a projection lens and has less unevenness in light amount. The optical modulation device 40 functions as a shutter that controls the transmittance of color light having image information when used in combination with the polarizing plates 22 and 23.

By configuring the optical modulation device in this manner, the same effect as when using the polymer dispersion type liquid crystal for the optical modulation controlled portion can be obtained, and at the same time, by using the TN type liquid crystal, a high contrast can be obtained. An image display device can be provided.

In addition to the TN type liquid crystal, other optical modulation controlled parts such as a guest host liquid crystal may be used.

FIG. 21 shows the optical modulator of FIG. 19 from which the light-collecting element 2 on the emission side having a function as a collimating element is removed. With such a configuration, the light beam emitted from the optical modulator 50 exits with a certain spread.
In this case, as compared with the optical modulation device 40 shown in FIG. 19, when the F-number of the projection lens is constant, the screen illuminance slightly decreases. However, since the thickness L of the glass substrate 3 is sufficiently large with respect to the size d of one pixel of the optical modulation element 21 and the spread angle of the emitted light beam is considerably small, it is considered that there is not much problem in practical use. With this configuration, the number of optical members can be reduced, so that the adjustment process and the cost of parts can be reduced.

In the transmission type optical modulation device, the same arrangement as that shown in FIGS. 9 to 13 can be applied to the arrangement relationship between the condensing element and the optical modulation element.

FIG. 22 shows an optical modulator according to another embodiment of the present invention.

In FIG. 22, components having the same reference numerals as those in FIG. 1 have the same functions, and therefore description thereof will be omitted. In the optical modulation device 60 of the present embodiment, a flat microlens 8 is inserted between the transparent substrate 3 and the optical modulation element group 1. With this configuration, the white light incident on the light condensing element A0 is separated by the color separation / combination element S0 into color light of each of the RGB wavelength bands, and the main light of each color light is converted by the flat microlens 8 into the optical modulation elements T0, T-. The light is deflected so as to be perpendicular to 1, T + 1, respectively, enters the optical modulation elements T0, T-1, T + 1, and is reflected by the reflector 8. Each color light modulated by the optical modulation element follows the reverse optical path, is incident again on the color separation / combination element S0, is combined, is converted into parallel light by the light condensing element A0, and exits from the optical modulation device 60. That is, the optical modulation device 60 of the present embodiment has three
The pixels of each of the three color components correspond to each other.

As shown in FIG. 23, the flat microlens 8 is based on a substrate having the same refractive index n0 as the transparent substrate 3 and
The refractive index n1 of only the lens part that enters and exits −1 and T + 1 is formed higher than n0. In the present embodiment, a flat microlens is used, but a trapezoidal lens as shown in FIG. 24 or a lenticular lens as shown in FIG. 25 may be used.

The color image display device using the optical modulation device 60 is the same as that shown in FIG.

By configuring the optical modulator in this way, the same effects as those of the optical modulator 10 shown in FIG. 1 can be obtained.

Although the color separation / synthesis element 6 has not been described in detail, it is possible to use a color separation / synthesis element which is the same as that shown in FIG. In the present embodiment, the latter is used.

In this embodiment, a one-dimensional blazed diffraction grating is used for the color separation / synthesis element as in the above embodiments, but other color separation elements such as holograms are used for the color separation / synthesis element. It does not matter. Further, the reflection plate 7 may be formed simultaneously with a metal layer when forming the wiring portion of the optical modulation element group 1. Further, the light collecting element 2 may be a flat microlens. The color separation element group 6
May be formed integrally with the light-collecting element group 2 or the transparent substrate 3.

As shown in FIG. 26, the color filter 51
27, the light shielding wall 6 is provided between the optical modulation elements as shown in FIG.
By providing 1, a high-quality image display device can be provided.

FIG. 28 shows an embodiment in which a TN type liquid crystal is used for the optical modulation controlled part. With such a configuration, the same effects as those of the above-described embodiments can be obtained.

The structure of the color image display device is the same as that shown in FIG. Further, in the present embodiment, the TN liquid crystal is used as the optical modulation controlled part, but another optical modulation controlled part such as a guest host liquid crystal may be used. In FIG. 8, since the polarization beam splitter 19 does not have sufficient polarization separation accuracy, the condenser lens 13 is used to further improve the contrast.
One polarizing plate may be added between the polarizing beam splitter 19 and the polarizing beam splitter 19.

FIGS. 29 to 32 are plan views of the optical modulator according to the present embodiment as viewed from the incident side, and show the relationship between the arrangement of the light condensing element and the optical modulation element.

FIG. 29 shows the optical modulator of the present invention in which the light incident on the optical modulator including the optical axis of the light-collecting element (the letter with an underbar in FIG. 29) is colored G. At the same time, the adjacent optical modulation element in the direction perpendicular to the color separation direction of an arbitrary color separation / synthesis element is also set to G color. The light-collecting element has a shape in which the refractive power of the lens in the direction parallel to the two sides of the optical modulation element is different from each other, and the light beam incident on the light-collecting element A0 is condensed on the color separation element S0. By arranging the light condensing element and the optical modulation element in this manner, the binary diffraction grating has a continuous shape in a certain one-dimensional direction, so that the formation is easy and the cost can be reduced.

Further, as shown in FIG. 30, the light-collecting element can be a lenticular lens. in this case,
Although the black matrix structure in the direction having no power of the lenticular lens cannot be removed and remains, by changing the configuration of the black matrix while keeping the aperture ratio constant, almost the same effect as the example shown in FIG. 29 can be obtained. can get. Further, although one element shape of the optical modulation element is a square, it may be a rectangle.

FIG. 31 shows that in the optical modulation device of the present invention, the light incident on the optical modulation element including the optical axis of the light collection element (the letter with an underbar in FIG. 31) is colored G and the light collection element 2 Are arranged in a staggered arrangement. By arranging the light condensing element and the optical modulation element in this manner, FIG.
The same effect as that shown in FIG. Further, in FIG. 31, the two-dimensional array of the optical modulation elements is arranged in a lattice, but the same effect can be obtained even in a staggered arrangement as shown in FIG.

FIG . 33 shows a transparent lens having a flat microlens 8.
1 shows an over-shaped optical modulator. Optical modulation elements T0, T0-
1 and T0 + 1 are the same as the reflection type optical modulation element 60 shown in FIG. Each color light modulated and emitted by the optical modulation elements T0, T0-1 and T0 + 1 is bent into an optical path by the plane-side microlens 8 on the emission side, enters the diffraction grating M0, is synthesized, and becomes parallel light from the condensing element B0. Out.

The color image display device is the same as that shown in FIG. 4 and will not be described.

As shown in FIG. 34, the color filter 51
And the light shielding wall 6 between the optical modulation elements as shown in FIG.
By providing 1, a high-quality image display device can be provided.

FIG. 36 shows an embodiment in which a TN type liquid crystal is used for the optical modulation controlled portion. With such a configuration, the same effects as those of the above-described embodiments can be obtained.

The structure of the color image display device is the same as that shown in FIG. Also,
In the present embodiment, TN is used as the optical modulation controlled part.
Although a liquid crystal is used, other optical modulation controlled parts such as a guest host liquid crystal may be used. In order to further improve the contrast because the polarization splitting accuracy of the polarizing beam splitter 19 in FIG. 18 is not sufficient, one polarizing plate may be added between the condenser lens 13 and the polarizing beam splitter 19.

FIG. 37 shows the optical modulator of FIG. 36 from which the light-collecting element 2 on the emission side having a function as a collimating element is removed. With this configuration, the light beam emitted from the optical modulation device 100 exits with a certain spread.
In this case, when compared with the optical modulator 90 shown in FIG. 36, when the F-number of the projection lens is constant, the screen illuminance slightly decreases. However, since the thickness L of the glass substrate 3 is sufficiently large with respect to the size d of one pixel of the optical modulation element 21 and the spread angle of the emitted light beam is considerably small, it is considered that there is not much problem in practical use. With this configuration, the number of optical members can be reduced, so that the adjustment process and the cost of parts can be reduced.

[0078]

As described above, according to the present invention,
With good light use efficiency, a small optical modulator can be realized, and if the optical modulator of the present invention is used for a color image display device,
A device with good image quality can be realized without increasing the size of the device.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 2 is an enlarged sectional view of a diffraction grating.

FIG. 3 is a schematic diagram of a color image display device of the present invention.

FIG. 4 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 5 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 6 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 7 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 8 is a schematic diagram of a color image display device of the present invention.

FIG. 9 is a diagram showing the relationship between the arrangement of a light-collecting element and an optical modulation element.

FIG. 10 is a diagram showing a relationship between the arrangement of a light condensing element and an optical modulation element.

FIG. 11 is a diagram showing a relationship between arrangement of a light condensing element and an optical modulation element.

FIG. 12 is a diagram showing a relationship between arrangement of a light condensing element and an optical modulation element.

FIG. 13 is a diagram showing the relationship between the arrangement of a light condensing element and an optical modulation element.

FIG. 14 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 15 is a schematic diagram of a color image display device of the present invention .

FIG. 16 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 17 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 18 is a schematic view of a color image display device of the present invention .

FIG. 19 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 20 is a schematic view of a color image display device of the present invention .

FIG. 21 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 22 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 23 is an enlarged sectional view of a flat microlens.

FIG. 24 is an enlarged sectional view of a flat microlens.

FIG. 25 is an enlarged sectional view of a flat microlens.

FIG. 26 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 27 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 28 is a sectional view of a main part of a reflection type optical modulation device of the present invention.

FIG. 29 is a diagram showing the relationship between the arrangement of the light condensing element and the optical modulation element.

FIG. 30 is a diagram showing the relationship between the arrangement of a light-collecting element and an optical modulation element.

FIG. 31 is a diagram showing the relationship between the arrangement of a light condensing element and an optical modulation element.

FIG. 32 is a diagram showing the relationship between the arrangement of the light condensing element and the optical modulation element.

FIG. 33 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 34 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 35 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 36 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 37 is a sectional view of a main part of a transmission type optical modulation device of the present invention .

FIG. 38 is a sectional view of a main part of a conventional optical modulation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical modulation element 2 Condensing element 3 Transparent substrate 4 Light shielding film 6 Diffraction grating 7 Reflector 10 Optical modulation device 11 White light source 12 Parabolic mirror 13 Condenser lens 14 Projection lens 15 Projection lens stop 16 Projection screen 17 Condensing lens 18 Mirror 51 Color filter 61 shading wall

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-249318 (JP, A) JP-A-62-293223 (JP, A) JP-A-7-49489 (JP, A) JP-A-7-49 92316 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/1335-1/1357

Claims (12)

(57) [Claims] 1. A light beam of a wide wavelength band having a different wavelength band from each other.
A diffraction grating that decomposes into a plurality of light fluxes, and each of the wavelength bands
Is modulated for each pixel and reflected by the reflector
An optical modulation device having an optical modulation element, wherein the diffraction grating is a one-dimensional binary diffraction grating, and the diffraction grating is modulated by the optical modulation element;
An optical modulation device comprising: combining the reflected light fluxes of the respective wavelength bands; and forming the optical modulation element and the diffraction grating integrally. 2. The diffraction grating according to claim 1, wherein the unit region has the wide wavelength
The direction of decomposing the luminous flux in the band is different, and the light is emitted in different directions
Of the optical modulation element into which the light beam of the same wavelength band
The light according to claim 1, wherein the light has a common pixel.
Modulation device. 3. A luminous flux emitted from the common pixel,
Incident on a plurality of unit areas of the diffraction grating.
The optical modulator according to claim 2. (4) Converts broadband light into multiple convergent beams
A light-condensing element group and the plurality of convergent light beams are respectively R, G, and B.
A diffraction grating for decomposing the light into three colors of light, and three colors of R, G and B
A plurality of pixels for modulating the light beam and the light beams of the three colors R, G, and B
And an optical modulation element comprising a reflecting plate for reflecting,
The diffraction grating is modulated and reflected by the optical modulation element.
An optical modulator for synthesizing light beams of three colors of R, G, and B, The diffraction grating is a one-dimensional binary diffraction grating,
The diffraction grating is provided for the plurality of light beams from the light-collecting element group.
A plurality of color separation areas each having a corresponding color separation area;
Color separation areas that are adjacent to each other in the color separation direction
The light flux of R color and the light flux of B color for the light flux of G color
The separation directions are opposite to each other, and the separation direction is opposite to the center of the color separation area.
There is a pixel of the G color at a corresponding position, and the adjacent color
At the position corresponding to the boundary between the separation areas,
There is a pixel of the elementary color or the color of B, from the color separation area
The luminous flux of the color G is incident on the pixel of the color G and the reflection plate
Incident on the same color separation area,
The luminous flux of the R color from each of the overlapping color separation areas is
Incident on pixels of the R color common to each other,
Incident on the adjacent color separation area by reflection at
Light of the color B from each of the adjacent color separation areas
The bundle enters the pixels of the B color that are common to each other, and
By being reflected by the firing plate, the light enters the adjacent color separation area.
An optical modulation device, comprising: (5) Converts broadband light into multiple convergent beams
A light-condensing element group and the plurality of convergent light beams are respectively R, G, and B.
A first diffraction grating for decomposing the light into three color light beams;
Optical modulation element having a plurality of pixels for modulating light beams of three colors
And the three colors R, G, and B modulated by the optical modulation element.
Optical modulator having second diffraction grating for synthesizing light beam
And The first diffraction grating is a one-dimensional binary diffraction grating
Thus, the first diffraction grating is provided by the light condensing element group.
It has a color separation area corresponding to each of a plurality of convergent light beams.
And a color component of the plurality of color separation regions of the first diffraction grating.
The color separation area adjacent to the solution direction is the luminous flux of the G color.
Separation direction of the light beam of the R color and the light beam of the B color with respect to
Are opposite to each other, and the optical modulation element
Having a pixel of G color at a position corresponding to the center of the area,
R is positioned at the position corresponding to the boundary between adjacent color separation areas.
Color pixels or B color pixels, The luminous flux of the G color from the color separation area is an image of the G color.
Incident on the element, and each of the two adjacent color separation areas
The light beams of the R colors are incident on the R pixels common to each other.
And from each of the two adjacent color separation areas
The luminous flux of the B color is incident on the B pixel common to each other, The second diffraction grating is a plurality of the first diffraction gratings.
There is a color composition area at the position corresponding to each of the color separation areas.
And In the color synthesis area, the G emitted from the pixel of the G color
The luminous flux of the color G and the pixel of the color G with respect to the color separation direction.
The R color pixel and the B color pixel
The light flux of the R color and the light flux of the B color emitted from
An optical modulator characterized by being projected and combined. 6. A light condensing means for converging the light beam in the wide wavelength band or the light beam decomposed into the predetermined wavelength band and causing convergent light to enter each pixel of the optical modulation element. the optical modulator of claim 1 to 3 any one of claims to. 7. The optical modulation device according to claim 4 , wherein a unit area of the light condensing unit and the diffraction grating or the first diffraction grating is paired. 8. The method according to claim 1, wherein the diffraction grating or the first diffraction grating is
Therefore, the color is placed at the position where the luminous flux is
8. A filter according to claim 1, further comprising a filter.
The optical modulator according to claim 1. 9. The liquid crystal display device according to claim 9, wherein the optical modulation element is a polymer-dispersed liquid crystal.
9. The method according to claim 1, wherein:
Optical modulator. 10. A light-shielding wall is provided between pixels of the optical modulation element.
The optical modulation device according to claim 9, comprising: 11. The optical modulation element is a TN type liquid crystal.
The method according to any one of claims 1 to 8, wherein
Optical modulator. 12. The method according to claim 1, wherein
Displaying a color image using an optical modulator
Color image display device.