JPH0950018A - Optical modulation device and color picture display device using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently collect light on each picture element and to improve a light utilization efficiency and a picture quality by resolving white illumination light into multiple color rays of light through a first diffraction grating. SOLUTION: White light flux collected at A0 passes through color resolving- multiplexing element S0 before it is resolved into three color rays of light in RGB bands. The three color rays of light are polarized by a flat micro lens 8 so that the main light beams of each color light become vertical to the optical modulation elements T0, T+1, T-1, and they are made incident on optical modulation elements T0, T+1, T-1 and are reflected off a reflection plate 7. In this case, a color resolving-multiplexing element group 6 is a resin molding of one-dimensional binary type diffraction grating. The light fluxes in individual wavelength bands are optically modulated before they are made to exit from the optical modulation elements T0, T+1, T-1 respectively. And after they are multiplexed by the optical modulation element S0, they are made to be approximately parallel rays of light through the light collecting element A0 to exit from it.

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, and this is a factor that lowers the light use efficiency of the entire device.

In order to solve this problem, the microlens 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 the white light source on each pixel of the optical modulation element 201 by arranging it on the front surface of 1R, 71G, 71B. Here, in FIG. 23, 3 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.

It is an object of the present invention to realize a single-plate color optical modulation device with a small loss of light amount, and at the same time to downsize the device.

[0006]

In order to achieve the above object, the first invention of the present application is to provide an optical modulator for modulating incident light for each pixel and emitting the modulated light, and a light beam having a wide wavelength band for each predetermined wavelength band. A first diffraction grating which is decomposed into a plurality of light beams, and a light beam decomposed by the first diffraction grating for each predetermined wavelength band is made incident on a different pixel of the optical modulation element, and the pixel has a predetermined wavelength band. An optical modulation device for modulating incident light is provided with a means for causing a principal ray of a light flux for each wavelength band decomposed by the first diffraction grating to vertically enter each pixel of the optical modulation element. To do.

A second invention of the present application is a color image display device characterized by displaying a color image using the optical modulator of the first invention of the present application.

In the optical modulator of the first invention of the present application, the white illumination light can be separated into a plurality of color lights by the first diffraction grating, and the white illumination light can be condensed to each pixel of the optical modulator corresponding to each color light without waste. Therefore, light utilization efficiency is improved, and a device with high image quality can be realized.

Further, according to the second invention of the present application, it is possible to provide a small-sized color image display device having good image quality.

[0010]

1 is a cross-sectional view (cross section parallel to the optical axis of the device) of an optical modulator that best represents 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 controlled 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. Reference numeral 6 is provided one-to-one with respect to the condensing element group 2, decomposes the light condensed by the condensing element group 2 into a plurality of color lights, and combines the color lights reflected from the optical modulation element group 1 and emits them. Is a color separation / synthesis element group. Reference numeral 7 is a reflector provided between the optical modulation element group 1 and the transparent substrate 3. Reference numeral 8 denotes a flat plate microlens for deflecting the color light separated by the color separation / combination element group 2 and making it incident on the optical modulation element.

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

In FIG. 1, arbitrary condenser elements are designated as A0 and A0.
The optical modulators including the optical axes of A + 1, A-1, and A0 (the center line of the converged light flux) are denoted by T0 and T0.
The color separation / synthesis element including the optical modulators T + 1, T-1, and A0 adjacent to is defined as S0, and the color separation / synthesis elements adjacent to S0 are defined as S + 1 and S-1. The white light flux condensed at A0 passes through the color separation / combination element S0, and is then separated into three color lights in the RGB band. The principal rays of the three color lights of the respective color lights are optical modulators T0 and T + by the flat plate microlens 8.
1, so that they are deflected so that they are perpendicular to T-1,
The light enters the optical modulators T0, T + 1, and T-1 and is reflected by the reflector 7
Is reflected by. The light flux in each wavelength band undergoes optical modulation until it exits the optical modulation elements T0, T + 1, and T-1. G modulated by the optical modulator T0
The light in the wavelength band of R is decomposed by the color separation / combination element S + 1 and modulated by the optical modulation element T + 1, and the light in the wavelength band of R is decomposed by the color separation / combination element S-1 and modulated by the optical modulation element T-1. The received light in the wavelength band of B is combined with the optical modulation element S0, and then is made into substantially parallel light in the condensing element A0 and emitted.

The flat microlens 8 is based on a substrate having the same refractive index n0 as the transparent substrate 3 as shown in FIG.
1, the refractive index n1 of only the lens part entering and exiting T + 1 is
It is formed higher than zero. In this embodiment, a flat plate microlens is used, but a trapezoidal lens as shown in FIG. 3 or a lenticular lens as shown in FIG. 4 may be used.

Since the principle of optical modulation by polymer dispersed liquid crystal is generally known, its explanation is omitted.

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

In this embodiment, the color separation / synthesis element group 6 is used.
Is a one-dimensional binary diffraction grating molded of resin. The one-dimensional binary diffraction grating is a diffraction grating formed stepwise as shown in FIG. 5, and is formed so that the deflection angles of diffracted light are all the same. In the present embodiment, the step widths L1 and L are set within the lattice pitch P.
It has a three-stage shape of 2, L3. If the number of stairs is 3 or more, the same effect can be obtained with 4 or 5 steps. A transmission type diffraction grating as shown in this embodiment mode is described in Applied Optics magazine Vol. 1 1
As disclosed in No. 5 Nos. 2273 to 2279 (1978.8.1), the incident light flux incident on the diffraction grating is transmitted and diffracted and is mainly separated 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.

The color separation has been described above, but the action of combining the three color lights by considering the paths of the light rays in the opposite direction will also be explained.

Next, FIG. 6 shows a schematic view of a reflection type color image display device using the optical modulator 10.

In FIG. 6, 10 is an optical modulator of the present invention, 1
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 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.

Image information of RGB color lights is obtained by the optical modulator 1.
It depends on the diffusivity of the light flux due to zero. When a diaphragm having an opening on the optical axis is used as shown in FIG. 6, a light flux having a low diffusion degree passes through the projection lens diaphragm 15 and reaches the projection screen 16, and a light flux having a high diffusion degree is used. The light is blocked by 15 and does not reach the projection screen 16.
That is, the image display device of FIG. 3 uses a light flux having a low degree of diffusion for image display. Contrary to the configuration shown in FIG. 3, when the diaphragm shape is such that the light flux near the optical axis is shielded, the light flux with a high degree of diffusion is used for image display.

With this configuration, the white light incident on the optical modulator 10 is separated into a plurality of color lights by the color separation / combination element group 6 and is condensed without waste on the optical modulation elements corresponding to the respective color lights. Therefore, the light utilization efficiency can be significantly 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 disappears on the screen and an image can be displayed in which the three RGB colors are completely combined, a high quality image can be displayed even when the screen is approached. It becomes possible to appreciate. Also,
Since the incident light flux is condensed for one pixel, a pixel having a low aperture ratio can be adopted, and therefore, there are many merits such that the manufacturing yield of the optical modulation element can be increased.

In this embodiment, the transmission diffraction grating is used as the color separation / combination element, but other color separation / combination elements such as holograms may be used. Further, the condensing element may be a flat plate microlens. Further, it is possible to reverse the order of arrangement of the light condensing element and the color separation / combination element. Further, the color separation / synthesis element group may be formed integrally with the light collecting element group or the transparent substrate.

In this embodiment, the number of pitches in one element of the color separation / combination element is two as shown in FIG. 5, but it needs to be changed according to the specifications of the optical modulator. Further, by slightly changing the grating thickness within one pitch of the diffraction grating for each step, and by designing the diffraction grating shape so that the grating widths within one pitch of the diffraction grating become unequal, the ± first-order diffracted light inner band is obtained. Since the components can be reduced, ideal color separation can be further achieved. Further, the reflector 7 may be simultaneously formed of a metal layer forming the wiring portion of the optical modulation element group 1.

Further, as shown in FIG. 7, a mode in which a color correction color filter 71 is provided at a position where each color light is separated is also conceivable. In this configuration, when the spectral characteristics of each color light separated by the color separation / combination element 6 are different from the spectral characteristics of the image signal, each color light is made incident on the color correction color filter 71 to obtain ideal color information. Faithful image color reproduction becomes possible. In this case, since the color filters 51 are transmitted after being decomposed into the respective color lights, the light utilization efficiency is not significantly lowered.

Further, as shown in FIG. 8, a mode in which a light-shielding wall 81 is provided between the optical modulation elements to prevent diffused light of polymer dispersed liquid crystal from entering adjacent elements and causing crosstalk is also possible. Conceivable. With this configuration, it is possible to provide a color image display device with higher image quality.

The color filter 7 shown in FIG.
It goes without saying that a mode in which the light shielding wall 81 shown in FIG.

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

In FIG. 9, those having the same reference numerals as those in FIG. . The optical modulator 20 of FIG. 9 is the most different from that of FIG.
This is the point used for. Along with that, the optical modulator 20 of the present embodiment has a polarizing plate 22.

Next, FIG. 10 shows a schematic view of a reflection type color image display device using the optical modulator 20.

In FIG. 10, those having the same reference numerals as those in FIG. Reference numeral 19 is a polarization beam splitter. The optical modulator 20 includes a polarizing plate 22.
And a reflective plate 7 in which the light beam phase difference changes by π upon reflection, are used in combination to serve as a shutter for controlling the transmittance of color light having image information. However, since the polarization axis of the polarizing plate 22 and the alignment direction of liquid crystal molecules are uniquely determined, the description thereof is omitted here.

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

In addition to the TN type liquid crystal, other optical modulation controlled parts such as guest host liquid crystal may be used. Further, in FIG. 10, when the polarization separation precision of the polarization beam splitter 19 is not sufficient, one more polarizing plate may be added between the condenser lens 13 and the polarization beam splitter 19 to further improve the contrast.

11 to 14 are plan views of the optical modulator of the present invention as seen from the incident side, showing the relationship between the arrangement of the condenser element and the optical modulator element.

FIG. 11 shows that in the optical modulator of the present invention, the incident light (the letter with an underbar in FIG. 11) incident on the optical modulator including the optical axis of the condensing element is of G color. At the same time, the adjacent optical modulation element in the direction perpendicular to the color separation direction of any color separation / synthesis element is also G color. Further, the light condensing element has a shape in which the refracting powers of the lenses in the directions parallel to the two sides of the optical modulation element are different, and the light flux incident on the light condensing element A0 is condensed on the color separation element S0. By arranging the condensing element and the optical modulation element in this way, the binary type 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. 12, the condensing element may be a lenticular lens. in this case,
Although the black matrix structure in the direction not having the power of the lenticular lens cannot be removed and remains, the same effect as the example shown in FIG. 11 can be obtained by changing the structure of the black matrix while keeping the aperture ratio constant. can get. Further, although the single element shape of the optical modulation element is square, it may be rectangular.

In FIG. 13, in the optical modulator of the present invention, the light incident on the optical modulator including the optical axis of the condenser (the letter with an underbar in FIG. 13) is of G color, and the condenser 2 Is a staggered arrangement. By arranging the condensing element and the optical modulation element in this way,
An effect similar to that shown in is obtained. Further, in FIG. 13, the two-dimensional array of the optical modulation elements is arrayed in a lattice shape, but the same effect can be obtained even with the staggered array as shown in FIG.

FIG. 15 is a diagram showing a transmission type optical modulator 30. 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
This is that the optical modulation element group 1 is sandwiched by the flat plate microlenses 8, and the condensing element group 2 and the color separation / synthesis element group 6 are provided in a pair on the incident side and the emitting side. Therefore, the light-collecting element group 2 on the emitting side functions as a collimating element, the color-separating / combining element group 6 on the incident side only performs color separation, and the light-emitting side only performs color combination.

Next, the image forming operation of the optical modulator 30 will be described. Similar to the case of FIG. 1, arbitrary condensing elements are A0, condensing elements adjacent to A0 are A0 + 1, A0-.
The optical modulation elements including the optical axes of 1 and A0 (the center line of the condensed light flux) are T0, and the optical modulation elements adjacent to T0 are T + 1 and T-.
1, the color separation / combination element on the incident side including the optical axis of A0 is S0,
The color separation / synthesis elements adjacent to S0 are S + 1, S-1, and A0.
The color separation / combination element on the output side including the optical axis of M0 and the color separation / combination element adjacent to M0 are connected to the light condensing element on the output side including the optical axes of M + 1, M-1, and A0 adjacent to C0 and C0. The optical elements are C + 1 and C-1. The white light flux condensed at A0 passes through the color separation / combination element S0, and is then separated into three color lights in the RGB band. The three color lights are deflected by the flat plate microlens 8, enter the optical modulators T0, T + 1, and T-1 and undergo optical modulation. The light in the G wavelength band that has been modulated by the optical modulator T0 is the color separation / synthesis device S + 1.
Light in the wavelength band of R that is decomposed by the optical modulation element T + 1 and is modulated by the color modulation / combination element S-1 and modulated by the optical modulation element T-1.
After being combined with the light of the wavelength band of 1 by the color separation / combination element M0, the light is converted into substantially parallel light by the condensing element C0 and emitted.

Next, FIG. 16 shows a schematic view of a transmission type color image display device using the optical modulator 30.

The light emitted from the white light source 11 is parabolic mirror 1.
The light is converted into substantially parallel light by 2 and enters the optical modulator 30.
The light to which the image information for each of the RGB color lights is given by the optical modulator 30 is 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 of RGB light is the optical modulator 3.
It depends on the diffusivity of the light flux due to zero. When a diaphragm having an opening on the optical axis is used as in the present embodiment, a light flux having a low diffusion degree passes through the projection lens diaphragm 15 and reaches the projection screen 16, and a light flux having a high diffusion degree is projected. The light is blocked by the lens diaphragm 15 and does not reach the projection screen 16. That is, the image display device of FIG. 16 uses a light flux with a low degree of diffusion for image display. Contrary to the present embodiment, when the aperture shape is such that the light flux near the optical axis is shielded, the light flux with a high degree of diffusion is used for image display.

FIG. 17 shows a color correction color filter 71 provided at a position where each color light is separated in the optical modulator of FIG. 15, and FIG. 18 shows each optical modulator of the optical modulator of FIG. A light shielding wall 81 is provided between them. By thus configuring the optical modulation device, it is possible to provide an image display device with high image quality. Incidentally, the position of the color correction color filter 71 may be on the front surface of the optical modulation element group 1.

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

In FIG. 16, a color image display device using only one optical modulation device 30 has been described, but in order to display a brighter image, the light source 11, the parabolic mirror 12, the condenser lens 17, and the optical modulation device 30 are shown. There is also an example of completely combining images by using two sets of illumination / optical modulation units consisting of. This example is shown in FIG.

With this configuration, it is possible to provide a device for business use which requires a brighter image display with a simple device structure.

For the optical modulation controlled portion, not only polymer dispersed type liquid crystal but also TN type liquid crystal can be used. The configuration is shown in FIG.
Shown in In FIG. 20, reference numeral 21 is an optical modulation element in which a TN type liquid crystal is used as an optical modulation controlled portion, and reference numerals 22 and 23 are polarizing plates having polarization axes orthogonal to each other.

FIG. 21 is a schematic view of a color image display device using this optical modulator. The optical system of the color image display device of FIG. 21 is generally called a Koehler illumination system, and is known as an optical system that forms an image of a light source on the pupil of a projection lens and has little unevenness in light amount. The optical modulator 40 serves as a shutter for controlling the transmittance of color light having image information by using it in combination with the polarizing plates 22 and 23.

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

Other than the TN type liquid crystal, other optical modulation controlled parts such as guest host liquid crystal may be used.

FIG. 22 does not include the light-collecting element 2 on the emission side, which has a function as a collimating element in the optical modulator of FIG. With such a configuration, the light flux emitted from the optical modulator 50 is emitted with a certain spread.
In this case, as compared with the optical modulator 40 shown in FIG. 20, when the F number of the projection lens is constant, the screen illuminance will be slightly lowered. However, since the thickness L of the transparent substrate 3 is sufficiently large with respect to the size d of one pixel of the optical modulation element 21 and the divergence angle of the emitted light beam is considerably small, it is considered that there is not much problem in practice. With this configuration, it is possible to reduce the number of optical members, and thus it is possible to reduce the adjustment process and the component cost.

Since the color image display device using the optical modulator 50 is the same as that shown in FIG. 21, its explanation is omitted.

Also in the transmission type optical modulator, the same arrangement relationship between the condenser element and the optical modulator element as shown in FIGS. 11 to 14 can be applied.

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

Also in this embodiment, another color separation element such as a hologram may be used as the color separation / combination element. Further, the condenser element 2 may be a flat plate microlens. Further, the color separation element 6 may be formed integrally with the condensing element 2 or the transparent substrate 3.

[0058]

As described above, according to the present invention,
It is possible to realize a small-sized optical modulation device with good light utilization efficiency. If the optical modulation device 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 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 cross-sectional view of a flat plate microlens.

FIG. 3 is an enlarged cross-sectional view of a flat plate microlens.

FIG. 4 is an enlarged cross-sectional view of a flat plate microlens.

FIG. 5 is an enlarged cross-sectional view of a color separation / combination element.

FIG. 6 is a schematic view of a color image display device of the present invention.

FIG. 7 is a cross-sectional view of a main part of a reflection type optical modulator of the present invention.

FIG. 8 is a cross-sectional view of a main part of a reflection type optical modulator of the present invention.

FIG. 9 is a cross-sectional view of essential parts of a reflection-type optical modulator of the present invention.

FIG. 10 is a schematic view of a color image display device of the present invention.

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

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

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

FIG. 14 is a diagram showing a relation of arrangement of a light converging element and an optical modulation element.

FIG. 15 is a cross-sectional view of an essential part of a transmission type optical modulator of the present invention.

FIG. 16 is a schematic view of a color image display device of the present invention.

FIG. 17 is a cross-sectional view of a main part of a transmission type optical modulator of the present invention.

FIG. 18 is a cross-sectional view of an essential part of a transmission type optical modulator of the present invention.

FIG. 19 is a schematic view of a color image display device of the present invention.

FIG. 20 is a cross-sectional view of essential parts of a transmission type optical modulator of the present invention.

FIG. 21 is a schematic view of a color image display device of the present invention.

FIG. 22 is a cross-sectional view of an essential part of a transmission type optical modulator of the present invention.

FIG. 23 is a cross-sectional view of a main part of a conventional optical modulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical modulation element 2 Condensing element 3 Transparent substrate 4 Light-shielding film 5 Optical modulation control section 6 Color separation / synthesis element 7 Reflector 8 Flat plate microlens 10 Optical modulation device 11 White light source 12 Parabolic mirror 13 Condenser lens 14 Projection lens 15 Projection lens Aperture 16 Projection screen 17 Condenser lens 18 Mirror 71 Color filter 81 Light-shielding wall

Claims (17)

[Claims] 1. An optical modulation element for modulating incident light for each pixel and emitting the modulated light, and a first diffraction grating for decomposing a light beam of a wide wavelength band for each predetermined wavelength band. In the optical modulation device, the light beams decomposed into predetermined wavelength bands by the diffraction grating are made incident on different pixels of the optical modulation element, and the pixels modulate the incident light in the predetermined wavelength band. An optical modulation device comprising means for vertically entering the principal ray of the light flux of each wavelength band decomposed by the above into each pixel of the optical modulation element. 2. The optical modulation element, the first diffraction grating, and means for vertically injecting a principal ray of a light beam for each wavelength band into different pixels of the optical modulation element are integrally formed. The optical modulation device according to claim 1, wherein the optical modulation device is provided. 3. The optical modulation device according to claim 1, further comprising a light combining unit that combines the emitted light for each wavelength band modulated by the optical modulation element into a light flux having image information. . 4. The optical modulator according to claim 3, wherein the light combining unit is a second diffraction grating. 5. A means for causing a principal ray of a light beam for each wavelength band, which is modulated by the optical modulator and vertically emitted from each pixel, to enter the light combining means at a predetermined angle. 3. The optical modulation device described in 3 or 4. 6. The optical modulation element, the first diffraction grating, means for vertically entering the principal ray of the light flux for each wavelength band into different pixels of the optical modulation element, and the optical modulation element. 6. A unit for causing a principal ray of a light beam for each wavelength band that is modulated and vertically emitted from each pixel to enter the light combining unit at a predetermined angle is integrally formed. Optical modulator. 7. A light condensing unit for converging the light flux of the wide wavelength band or the light flux decomposed for each of the predetermined wavelength bands to make the convergent light incident on each pixel of the optical modulation element. The optical modulation device according to claim 1. 8. The optical modulation device according to claim 1, further comprising a color filter at a position where the light flux is decomposed for each predetermined wavelength band by the first diffraction grating. 9. The optical modulation device according to claim 1, wherein the optical modulation element is a polymer-dispersed liquid crystal. 10. The optical modulation device according to claim 9, further comprising a light blocking wall between pixels of the optical element. 11. The optical modulation device according to claim 1, wherein the optical modulation element is a TN liquid crystal. 12. The optical modulation device according to claim 1, further comprising a reflection plate, wherein the reflection plate reflects the light flux for each wavelength band modulated by the optical modulation element. 13. The optical modulator according to claim 12, wherein the first diffraction grating and the light combining means are the same member. 14. Means for vertically injecting a principal ray of a light beam for each wavelength band into different pixels of the optical modulation element, and for each wavelength band which is modulated by the optical modulation element and is vertically emitted from each pixel. 14. The optical modulator according to claim 12, wherein the principal ray of the luminous flux is incident on the light combining means at a predetermined angle is the same member. 15. The diffraction grating and the condensing means are respectively provided on the incident side of the optical modulation element.
11. The optical modulator according to any one of 1 to 11. 16. Means for vertically injecting a principal ray of a light beam of each wavelength band into different pixels of the optical modulation element and / or each wavelength band which is modulated by the optical modulation element and vertically emitted from each pixel. 16. The optical modulation element according to claim 1, wherein the means for causing the principal ray of each light flux to enter the light combining means at a predetermined angle is a flat plate microlens. 17. A color image display device, which displays a color image using the optical modulation device according to any one of claims 1 to 16.