JP2003344946A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type display device which is small-sized and can project a color image of sufficient lightness. <P>SOLUTION: White light W from a light source 1 is made incident on a diffraction grating laminate 4 formed by laminating diffraction grating elements 5R, 5G, and 5B which have diffraction grating effect of reflecting wavelength light of one of red, blue, and green and transmitting other wavelength light in the absence of an electric field and lose the effect when applied with an electric field to transmit light beams of all the wavelength. Light beams of red, green, and blue emitted in order from the diffraction grating laminate 4 are split by a polarization beam splitter 13 into S-polarized components and P-polarized components, which are made incident on 1st and 2nd reflection type display bodies 17a and 17b. Then monochromatic image light beams whose planes of polarization are rotated by 90° from the incident light beams are projected from those reflection type display bodies 17a and 17b, both monochromatic image light beams from the display bodies are put one over the other by the polarization beam splitter 14 and projected on a projection system 29, thereby displaying a color image through time-difference composition of the monochromatic color image light beams of red, green, and blue. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device that projects a color image.

[0002]

2. Description of the Related Art A projection display device for projecting a multicolor image such as a full-color image uses a color image display having color filters of a plurality of colors and projects color image light emitted from the display. What is projected by the system, using a plurality of display bodies that display a monochromatic image of the color of the wavelength band of the incident light, the colored light of different wavelength bands are respectively incident on these display bodies, and from the plurality of display bodies There is one in which a plurality of monochromatic image lights of respective colors respectively emitted are combined into one color image light by a projection system and projected.

[0003]

However, since the color image display provided with the color filter has a large absorption of the light by the color filter, the intensity of the emitted light is extremely low with respect to the intensity of the incident light. The projection display device using this display body has a problem that the projected image is dark.

On the other hand, the display body for displaying a monochromatic image of the color of the wavelength band of the incident light does not absorb the light by the color filter, so that there is almost no decrease in the intensity of the emitted light with respect to the intensity of the incident light. A projection display device using a body can project a color image with sufficient brightness.

However, in this projection type display device, it is necessary to dispose a light source system for making light beams of different wavelength bands respectively incident on a plurality of display bodies.
There are problems that the entire device becomes large and the cost becomes high.

It is an object of the present invention to provide a projection type display device which is small in size and can project a color image of sufficient brightness.

[0007]

A projection type display device of the present invention comprises a light source for emitting white light, a light extraction means for extracting the light of the light source into a plurality of wavelength bands in a time division manner, and an image from the incident light. The first and second reflective display bodies that generate light, and the light extracted by the light extraction means are further separated into two luminous fluxes, which are made incident on the first and second reflective display bodies. A beam splitter for synthesizing the image light generated by the first and second reflection type display bodies, and a projection system for projecting the image light synthesized by the beam splitter, and color display is performed in a time division manner. To do.

In this projection type display device, the light of the light source is time-divided into a plurality of wavelength bands by the light extraction means, and the light of the extracted wavelength bands is separated by the beam splitter to produce the first and second light beams. When the reflection type display bodies are made to enter, the reflection type display bodies are caused to generate image light of colors of the plurality of wavelength bands, and the image light generated by the first and second reflection type display bodies is made to be the beam. Since color display is performed in a time-division manner by combining with a splitter and projecting the combined image light with a projection system, it is possible to project a small-sized and sufficiently bright color image.

Further, the projection display device of the present invention includes a light source that emits white light, and a wavelength light in one wavelength band of a specific wavelength band of the visible light band and another wavelength band when there is no electric field. A plurality of diffraction gratings that have a diffraction grating effect that reflects light of the other wavelength band and that transmits the wavelength light of all wavelength bands of the visible light band by losing the diffraction grating effect by the application of an electric field. A diffraction grating laminated body in which elements are laminated and the reflection / transmission wavelength bands of the plurality of diffraction grating elements are different from each other when there is no electric field;
Of the two polarization components of the light incident from the incident surface, which are orthogonal to each other, and emit the light of one polarization component from the first input / output surface and the other of the two. The light of the polarization component is emitted from the second entrance / exit surface, and
A polarization beam splitter that emits the light of the other polarization component that has entered from the first entrance / exit surface and the light of the one polarization component that entered from the second entrance / exit surface from the exit surface, and from the front side. Incident light is reflected, and the reflected light is emitted to the front side to display a monochromatic image of a color in the wavelength band of the incident light, and the polarization plane is substantially 90 degrees with respect to the incident light.
The first and second reflection type display bodies that emit the light of the polarization state rotated by ° to the front side, and the projection system that projects the emission light from the first and second reflection type display bodies, and the light source The diffraction grating laminated body is disposed on the emission side of, and the polarization beam splitter has its incident surface facing the diffraction grating laminated body on the emission side of either the reflected light or the transmitted light of the diffraction grating laminated body. The first and second reflective display bodies are arranged so as to face the first and second entrance / exit surfaces of the polarization beam splitter, respectively, and face the exit surface of the polarization beam splitter. The projection system is arranged.

That is, this projection type display device reflects white light from a light source and, when there is no electric field, reflects wavelength light in one wavelength band of a specific wavelength band of the visible light band and another wavelength band. , A plurality of diffraction grating elements which have a diffraction grating effect of transmitting wavelength light of the other wavelength band, lose the diffraction grating effect by application of an electric field, and transmit wavelength light of all wavelength bands of the visible light band The colored light beams of a plurality of colors are sequentially emitted from the diffractive grating layered product, and the colored light beams of one polarized component and the other polarized component are output by the polarizing beam splitter. The light is separated into light and is incident on the first reflective display body and the second reflective display body, and each of these reflective display bodies has a polarization plane substantially with respect to the incident light from the front side thereof. Rotated 90 ° The monochromatic image light in the light state is emitted to the front side, and both of the monochromatic image lights are superposed by the polarization beam splitter and projected by the projection system, whereby the monochromatic image lights are sequentially emitted from the first and second reflective display bodies. A color image obtained by time-difference synthesis of monochromatic image lights of a plurality of colors projected by the projection system is displayed on a projection surface such as a screen.

According to this projection type display device, since only one light source is required, it is possible to reduce the size of the entire device, and moreover, the colored light beams of a plurality of colors are sequentially emitted from the diffraction grating laminate, and the same light source is produced. The colored beam of light is separated into light of one polarization component and light of the other polarization component by the polarization beam splitter, and is made incident on the first and second reflection type display bodies, and these reflection type display bodies are also provided. Respectively, the monochromatic image light in the polarization state in which the polarization plane is rotated substantially 90 ° with respect to the incident light from the front side is emitted to the front side, and both the monochromatic image lights are projected by being superimposed by the polarization beam splitter. Therefore, the colored lights of a plurality of colors sequentially emitted from the diffraction grating laminated body are used with high efficiency with almost no waste, and the display brightness of one reflection type display body is about 2 or less. Double monochromatic Projecting the image light, it is possible to display a color image of sufficient brightness by the time difference synthesis of monochromatic image light of a plurality of colors on a projection plane.

In this projection type display device, each of the first and second reflection type display bodies reflects the incident light from the front side, emits the reflected light to the front side, and colors in the wavelength band of the incident light. It is desirable that the reflective display element for displaying the single color image and the retardation plate disposed on the front side of the reflective display element.

In this case, the reflective display element has a liquid crystal layer in which a black dichroic dye is mixed, absorbs light incident from the front side when no electric field is applied, and absorbs light incident from the front side when an electric field is applied. Is a reflection type liquid crystal display device that reflects the light in its polarized state and emits it to the front side, and the retardation plate gives a phase difference of ¼ wavelength between the ordinary light of the transmitted light and the extraordinary light.
A retardation plate is preferable.

The diffraction grating laminate has a diffraction grating element that reflects or transmits wavelength light in the red wavelength band when there is no electric field and a diffraction grating element that reflects or transmits wavelength light in the green wavelength band when there is no electric field. And a diffraction grating element that reflects or transmits wavelength light in the blue wavelength band when there is no electric field is desirable.

[0015]

1 to 5 show a first embodiment of the present invention, and FIG. 1 is a plan view of a projection type display device.

As shown in FIG. 1, the projection type display apparatus of this embodiment has a light source 1 and a diffraction grating provided as a light extracting means for extracting the light of the light source 1 into a plurality of wavelength bands in a time division manner. The laminated body 4, a beam splitter 14 for separating and combining light, first and second reflective display bodies 17a and 17b for generating image light from incident light, and a projection system 29 are provided.

The light source 1 is a white light source that emits white light of high brightness, and a light guide rod 2 for arranging the light emitted from the light source 1 into light having a uniform intensity distribution is arranged on the light emitting side. A condenser lens 3 for collimating the light emitted from the light guide rod 2 into parallel light is arranged on the light emitting side.

The light guiding rod 2 is, for example, a rectangular rod-shaped transparent rod, and the light incident from one end surface of the light guiding rod 2 is at the interface between the rod side surface and the air layer as the outside air as shown by the broken line in the figure. The light is guided while being totally reflected, and the light having a uniform intensity distribution is emitted from the other end.

The diffraction grating laminated body 4 provided as the light extraction means reflects the wavelength light in one wavelength band of the specific wavelength band and the other wavelength band of the visible light band when there is no electric field, Having a diffraction grating effect of transmitting wavelength light of the other wavelength band, a plurality of diffraction grating elements that lose the diffraction grating effect by application of an electric field and transmit all wavelength light of the visible light band are stacked, and A plurality of diffraction grating elements have different reflection / transmission wavelength bands when no electric field is applied.

The diffraction grating laminate 4 used in this embodiment is
Has a diffraction grating effect of transmitting wavelength light R in the red wavelength band and reflecting wavelength lights of other wavelength bands when there is no electric field, and loses the diffraction grating effect due to the application of an electric field, and all wavelength light in the visible light band. Has a diffraction grating effect of transmitting wavelength light G in the green wavelength band when there is no electric field and reflecting wavelength light in other wavelength bands when there is no electric field. The second diffraction grating element 5G that loses its effect and reflects all wavelength light in the visible light band, and the diffraction that transmits the wavelength light B in the blue wavelength band when there is no electric field and reflects the wavelength light in other wavelength bands. It is composed of a laminated body with a third diffraction grating element 5B which has a grating effect and loses the diffraction grating effect by application of an electric field and transmits light of all wavelengths in the visible light band.

FIG. 2 shows the first of the first to third diffraction grating elements 5R, 5G and 5B constituting the diffraction grating laminate 4.
Sectional views of a part of the diffraction grating element 5R of FIG.
FIG. 4 is an enlarged cross-sectional view of the first diffraction grating element 5R when there is no electric field and when an electric field is applied.

In this diffraction grating element 5R, single film-like transparent electrodes 8 and 9 are formed on the inner surfaces of a pair of transparent substrates 6 and 7 which face each other. A polymer / liquid crystal composite layer 10 including a molecular layer 11 and a plurality of liquid crystal layers 12 dispersed in the polymer layer 11 is provided, and the pair of substrates 6 and 7 are provided at their peripheral portions. The polymer / liquid crystal composite layer 10 is bonded via a frame-shaped seal material (not shown), and is provided in a region surrounded by the seal material between the pair of substrates 6 and 7.

The plurality of liquid crystal layers 12 of the polymer / liquid crystal composite layer 10 of the first diffraction grating element 5R have positive dielectric anisotropy, and the liquid crystal molecules 12a are oriented in random directions as shown in FIG. In the absence of an electric field, the polymer layer 11 exhibits a refractive index substantially equal to that of the polymer layer 11 with respect to the wavelength light in the red wavelength band of the visible light band, and the polymer layer with respect to the wavelength light in other wavelength bands. 11 has a refractive index different from that of the above-mentioned electrodes 8 and 9 and
When the liquid crystal molecules 12a are aligned with their long axes aligned in a direction substantially perpendicular to the surfaces of the substrates 6 and 7 by applying an electric field between them, all wavelengths in the visible light band are It is made of a nematic liquid crystal having a wavelength dependence of the refractive index which shows a refractive index substantially equal to that of the polymer layer 11 with respect to light.

The polymer / liquid crystal composite layer 10 is
As shown in FIGS. 2 to 4, the plurality of liquid crystal layers 12 are substantially parallel to the direction along the horizontal axis of the pair of substrates 6 and 7 (the direction perpendicular to the plane of the drawing) and the substrates. Arranged along the length direction and the width direction (thickness direction of the polymer / liquid crystal composite layer 10) of a plurality of inclined surfaces inclined at an inclination angle of about 30 ° to 60 ° in one direction with respect to the vertical line of the surface. It has a structure.

2 to 4, the plurality of liquid crystal layers 12 of the polymer / liquid crystal composite layer 10 are shown to be arranged in order, but the arrangement state of the plurality of liquid crystal layers 12 is as follows. Actually, it is not in an orderly arranged state, but in a state substantially arranged along the plurality of inclined surfaces.

2 to 4, the intervals between the liquid crystal layer groups arranged along the plurality of inclined surfaces are greatly exaggerated, but the intervals between these liquid crystal layer groups are several .mu.m. Tens of μ
It is about m.

In this first diffraction grating element 5R, when no electric field is applied between the electrodes 8 and 9, that is, when the liquid crystal molecules 12a of the liquid crystal layer 12 of the polymer / liquid crystal composite layer 10 are oriented in random directions. In this state, the liquid crystal layer 12 exhibits a refractive index substantially equal to that of the polymer layer 11 with respect to the wavelength light in the red wavelength band, and the polymer layer 11 with respect to the wavelength light in the other wavelength band. 3 shows a refractive index different from that of FIG. 3, it transmits the wavelength light R of the red wavelength band of the white light W incident from one surface and transmits the other wavelength bands of green and blue. The wavelength lights G and B in the wavelength band are arranged on the interface between the polymer layer 11 and the liquid crystal layer 12, and the alignment surface (tilted surface) of the liquid crystal layer 12 is formed.
And the liquid crystal molecules 12a of the liquid crystal layer 12 of the polymer / liquid crystal composite layer 10 are substantially perpendicular to the surfaces of the substrates 6 and 7 between the electrodes 8 and 9. When an aligning electric field is applied, as shown in FIG.
The white light W incident from one surface is transmitted as it is.

The second and third diffraction grating elements 5 are
Although not shown, G and 5B are the first diffraction grating element 5
The second diffraction grating element 5G has the same configuration as R.
The plurality of liquid crystal layers of the polymer / liquid crystal composite layer are substantially as polymer layers with respect to the wavelength light G in the green wavelength band of the visible light band when the liquid crystal molecules are oriented in random directions and no electric field is applied. And a refractive index different from that of the polymer layer for light in other wavelength bands, and when the liquid crystal molecules are aligned substantially perpendicular to the substrate surface, visible light The wavelength dependence of the refractive index is substantially the same as that of the polymer layer for all wavelength light in the band.

Further, the polymer of the third diffraction grating element 5B /
The plurality of liquid crystal layers of the liquid crystal composite layer have a refractive index substantially equal to that of the polymer layer with respect to the wavelength light B in the blue wavelength band of the visible light band when the liquid crystal molecules are oriented in random directions and no electric field is applied. Shows a refractive index different from that of the polymer layer for light of wavelengths in other wavelength bands, and when the liquid crystal molecules are aligned substantially perpendicular to the substrate surface, all visible light bands are shown. The wavelength dependence of the refractive index is substantially the same as that of the polymer layer with respect to wavelength light.

That is, the second diffraction grating element 5G
Transmits the wavelength light G in the green wavelength band of the white light W incident from one surface when there is no electric field and reflects the wavelength lights R and B in the other wavelength bands of red and blue. At the same time, the white light W incident from one surface when an electric field is applied is transmitted as it is, and the third diffraction grating element 5B has a wavelength in the blue wavelength band of the white light W incident from one surface when no electric field is applied. The light B is transmitted, the wavelength lights R and G in the other wavelength bands of red and green are reflected, and the white light W incident from one surface when an electric field is applied is transmitted as it is.

The first to third diffraction grating elements 5 are
R, 5G and 5B are the respective polymer / liquid crystal composite layers 10
The liquid crystal layers 12 are laminated such that the aligned surfaces (tilted surfaces) thereof are parallel to each other.

The diffraction grating laminate 4 shown in FIG.
The first to third diffraction grating elements 5R, 5G, and 5B are replaced by a first diffraction grating element 5R, a second diffraction grating element 5G, and a third diffraction grating element 5G.
The diffraction grating elements 5B are laminated in this order, but the diffraction grating elements 5R, 5G, 5B may be laminated in any order.

As shown in FIG. 1, the diffraction grating laminate 4 has an incident surface on the emission side of the light source 1 (emission side of the condenser lens 3) with respect to the incident direction of the light from the light source 1. Are arranged almost vertically.

The diffraction grating elements 5R, 5G and 5B of the diffraction grating laminate 4 are provided with the diffraction grating elements 5
R, 5G, 5B are set to a constant cycle, for example, 20 msec to 30
A diffraction grating drive circuit 13 is connected to sequentially select the diffraction grating elements in a cycle of msec to put them in a non-electric field state and apply an electric field to other diffraction grating elements.

Further, the beam splitter 14 further separates the light extracted by the light extracting means composed of the diffraction grating laminated body 4 into two light fluxes to be divided into the first and second reflection type display bodies 17a and 17b. It is provided so as to be incident and to combine the image lights generated by the first and second reflective display bodies 17a and 17b.

The beam splitter 14 has two rod-shaped prisms 15a, 15 having a cross-section of an isosceles right triangle.
b, while making the respective inclined surfaces face each other,
In the meantime, of the two polarized light components of the incident light which are orthogonal to each other, one polarized light component (hereinafter referred to as S polarized light component) is reflected and the other polarized light component (hereinafter referred to as P polarized light component) is transmitted. A polarizing beam splitter is formed by laminating the reflective polarizing layer 16 with the reflective polarizing layer 16 interposed therebetween, and
One surface is an entrance surface 14a, one of two surfaces perpendicular to the entrance surface 14a is a first entrance / exit surface 14b, and a surface opposite to the entrance surface 14a is a second entrance / exit surface. Surfaces 14b and 14c, and the other of the two surfaces perpendicular to the entrance surface 14a is the exit surface 14d.

The polarization beam splitter 14 converts the light of the S polarization component, which is one of the two polarization components of the light incident from the incident surface 14a, which are orthogonal to each other,
The light of the P-polarized light component which is reflected by the reflective polarization layer 16 and is emitted from the first incident / emission surface 14b, and the other polarized light component is transmitted through the reflective polarization layer 16 to be the second incident / emission surface. The light of the P-polarized component that is emitted from the first incident / emission surface 14b is transmitted through the reflective polarization layer 16 and emitted from the emission surface 14d, and the second incident / emission surface 14c is emitted. The light of the S-polarized component that has entered from is reflected by the reflective polarization layer 16 and is emitted from the exit surface 1
Emit from 4d.

Then, this polarization beam splitter 14
Is the transmitted light emitted from the diffraction grating laminate 4 with the incident surface 14a thereof being substantially parallel to the transmitted light emission surface of the diffraction grating laminated body 4 on the emission side of the transmitted light of the diffraction grating laminated body 4. Are arranged so as to be incident on the incident surface 14a substantially vertically.

The first and second reflection type display bodies 17a, 1
Each of 7b reflects incident light from the front side, emits the reflected light to the front side, displays a monochromatic image of a color in the wavelength band of the incident light, and has a polarization plane substantially to the incident light. The light in the polarization state that is rotated by 90 ° is emitted to the front side.

FIG. 5 shows the first and second reflective display bodies 17 described above.
2A is a cross-sectional view of a part of a first reflective display body 17a of a and 17b, which reflects incident light from the front side and emits the reflected light to the front side to input the light. The reflective display element 18a displays a monochromatic image of a color in the wavelength band of the emitted light, and the retardation plate 27a arranged in front of the reflective display element 18a.

The reflective display element 18a is, for example, GH.
(Guest host) An effect type reflective liquid crystal display device,
Transparent electrodes 21 that form pixels arranged in a matrix in the row direction and the column direction on the inner surfaces of the front transparent substrate 19 that is the light input / output side and the rear transparent substrate 20 that faces the front substrate 19. , 22 and the electrodes 21, 22
Alignment films 23 and 24 are formed so as to cover the substrate, a nematic liquid crystal layer 25 in which a black dichroic dye is mixed is provided between the substrates 19 and 20, and the outer surface of the rear substrate 20 is provided. Alternatively, the reflective film 26 is provided on the inner surface (the outer surface in the figure).

The liquid crystal display element 17a is an active matrix liquid crystal display element having a TFT (thin film transistor) as an active element, and is one substrate, for example, the rear substrate 2
The electrode 22 provided on the inner surface of 0 is a plurality of pixel electrodes arranged in a matrix in the row direction and the column direction, and the electrode 21 provided on the inner surface of the other front substrate 19 is opposed to the plurality of pixel electrodes 22. This is a single film-shaped counter electrode.

Although not shown in FIG. 5, on the inner surface of the rear substrate 20, a plurality of TFTs respectively connected to the plurality of pixel electrodes 22 and a gate signal are supplied to the TFTs in each row. Multiple gate lines and TF in each column
A plurality of data lines for supplying data signals to T are respectively provided.

The pair of substrates 19 and 20 are bonded to each other at their peripheral portions via a frame-shaped sealing material (not shown), and the liquid crystal layer 25 is connected to the pair of substrates 19 and 20.
It is provided in a region surrounded by the sealing material between 20.

Liquid crystal molecules 25a of the liquid crystal layer 25
The dye molecules 25b and the dye molecules 25b are formed on the inner surfaces of the pair of substrates 19 and 20 by the alignment films 23 and 24, respectively.
The orientation direction in the vicinity of 20 is regulated, and a predetermined twist angle, for example, 90 ° is provided between these substrates 19 and 20.
The twist orientation is at the twist angle of.

In the liquid crystal display element 17a, the liquid crystal layer 25 is formed by applying an electric field between the electrodes 21 and 22 of each pixel.
Of the liquid crystal molecules 25a and the dye molecules 25b are controlled to display an image, and no electric field is applied between the electrodes 21 and 22, that is, the liquid crystal layer 25.
When the liquid crystal molecules 25a and the dye molecules 25b are in the twist alignment state, the light incident from the front side is absorbed by the dye molecules 25b, and the display of the pixel becomes black dark display.

The liquid crystal molecule 2 is provided between the electrodes 21 and 22.
When an electric field is applied to vertically orient 5a substantially perpendicularly to the surfaces of the substrates 19 and 20, the dye molecules 25b are vertically aligned with the liquid crystal molecules 25a, and the light incident from the front side is absorbed by the dye molecules 25b. Without passing through the liquid crystal layer 25 and reflected by the reflection film 26, the reflected light passes through the liquid crystal layer 25 again and is emitted to the front side,
The display of that pixel becomes a bright display.

On the other hand, the retardation plate 27a gives a λ / 4 phase difference of ¼ wavelength between the ordinary ray of the transmitted light and the extraordinary ray.
The retardation plate is attached to the outer surface of the front substrate 19 of the reflective liquid crystal display element 18a with its slow axis directed in a predetermined direction.

Incidentally, FIG. 5 shows the first reflection type display 17a.
However, the second reflective display body 17b also has the same configuration as the first reflective display body 17a, for example, G
H-effect reflection type active matrix liquid crystal display element 18b and λ / 4 retardation plate 27b arranged in front of it
It consists of

Then, as shown in FIG. 1, the first reflection type display 17a has the λ / 4 which is the entrance / exit surface thereof.
The outer surface of the phase difference plate 27a is attached to the polarization beam splitter 14
Of the second reflection type display body 17b, which is disposed so as to face the first entrance / exit surface 14b of the λ.
The outer surface of the / 4 phase plate 27b is arranged so as to face the second incident / emission surface 14c of the polarization beam splitter 14.

The reflection type liquid crystal display elements 18a of the first reflection type display body 17a and the second reflection type display body 17b,
18b has the same number of pixels and the same pixel pitch, and the first reflection type display 17a and the second reflection type display 17
b are the reflection type liquid crystal display elements 18a and 18b, respectively.
The center of the screen is arranged so as to face the center of the reflective polarization layer 16 of the polarization beam splitter 14.

Further, λ of the first reflective display body 17a is
The / 4 retardation plate 27 has its slow axis substantially with respect to the polarization plane of the light of the S-polarized component that enters from the entrance surface 14a of the polarization beam splitter 14 and exits from the first entrance / exit surface 14b. And the λ / 4 retardation plate 27 of the second reflective display body 17b has its slow axis at the incidence plane 1 of the polarization beam splitter 14.
4a and the light exiting from the second entrance / exit surface 14c are arranged so as to intersect the polarization plane of the light of the P-polarized component at an angle of substantially 45 °.

Further, the reflective liquid crystal display elements 18 of the first reflective display body 17a and the second reflective display body 17b.
a and 18b are liquid crystal display elements 18a and 18b.
Display element drive circuit 2 for synchronizing and displaying the same image on the display
8 is connected.

The display element drive circuit 28 sequentially selects a plurality of pixel rows of the reflective liquid crystal display elements 18a and 18b, sequentially outputs a gate signal to the gate wiring of the pixel rows, and selects each pixel row. A data signal corresponding to image data is output to a plurality of data lines of the liquid crystal display elements 18a and 18b at a timing, and the reflection type liquid crystal display elements of the first and second reflection type liquid crystal display bodies 17a and 17b. 18a and 18b are driven by the display element drive circuit 28, respectively, in synchronization with the emission of colored lights of a plurality of colors sequentially emitted from the diffraction grating laminate, and sequentially write the monochromatic image data of the colors of the colored lights. Get caught.

The projection system 29 is composed of a projection lens 30 constructed by combining a plurality of lenses, and is arranged so as to face the exit surface 14d of the polarization beam splitter.

In this projection display device, white light W is emitted from the light source 1, and the first to third diffraction grating laminated bodies 4 are arranged.
The diffraction grating elements 5R, 5G, and 5B are sequentially selected to bring the diffraction grating elements into a non-electric field state, an electric field is applied to the other diffraction grating elements, and the first and second reflection type display bodies 1 are provided.
The reflection type liquid crystal display elements 18a and 18b of 7a and 17b are respectively synchronized with the emission of the colored lights of the plurality of colors sequentially emitted from the first and second entrance / exit surfaces 14b and 14c of the diffraction grating laminate 4. It is driven by sequentially writing monochromatic image data of the color of the colored light.

That is, in the diffraction grating laminate 4, the first to third diffraction grating elements 5R, 5G and 5B are sequentially selected at a constant cycle (cycle of 20 msec to 30 msec) and the diffraction grating elements are subjected to no electric field. In this state, the white light W from the light source 1 is driven by the diffraction grating drive circuit 13 that applies an electric field to the other diffraction grating elements, and the white light W from the light source 1 is changed to colored light in the reflection / transmission wavelength band of the selected diffraction grating element. , The plurality of colored lights R, G and B corresponding to the reflection / transmission wavelength bands of the plurality of diffraction grating elements 5R, 5G and 5B, that is, red, green and blue, are sequentially emitted.

In this embodiment, as shown in FIG. 1, the first to third diffraction grating elements 5R, 5G and 5B are replaced by the first diffraction grating element 5R, the second diffraction grating element 5G and the third diffraction grating element 5G. Since the first diffraction grating element 5R is arranged toward the light source 1 side in the diffraction grating laminated body 4 in which the diffraction grating element 5B is laminated in this order, the first diffraction grating element 5R is set to the non-electric field state, Second
When an electric field is applied to the third diffraction grating elements 5G and 5B, the lights G and B in the green and blue wavelength bands of the white light W from the light source 1 are generated by the first diffraction grating element 5R. The light R in the red wavelength band that is reflected is transmitted through the first, second, and third diffraction grating elements 5R, 5G, and 5B and emitted.

Further, when the second diffraction grating element 5G is in the non-electric field state and the electric field is applied to the first and third diffraction grating elements 5R and 5B, the white light W from the light source 1 is the first. After passing through the diffraction grating element 5R and entering the second diffraction grating element 5G, light R in the red and blue wavelength bands of the white light W,
B is reflected by the second diffraction grating element 5G, and the light G in the green wavelength band is reflected by the second and third diffraction grating elements 5G.
G and 5B are transmitted and emitted.

Further, when the third diffraction grating element 5B is placed in the non-electric field state and an electric field is applied to the first and second diffraction grating elements 5R and 5G, the white light W from the light source 1 becomes first. The light R and G in the red and green wavelength bands of the white light W that has passed through the second diffraction grating elements 5R and 5G and enters the third diffraction grating element 5B is the third diffraction grating. The light B in the blue wavelength band reflected by the element 5B passes through the third diffraction grating element 5B and is emitted.

The colored light emitted from the diffraction grating laminate 4 is incident on the polarization beam splitter 14 through its incident surface 14a.
The light of the S polarization component, which is one polarization component of the two polarization components of the light that are orthogonal to each other, is reflected by the reflective polarization layer 16 of the polarization beam splitter 14, and is indicated by a solid line in FIG. As shown, the first entrance / exit surface 14b
Of the P-polarized light component, which is the other polarized light component,
The light passes through the reflective polarizing layer 16 and is emitted from the second incident / emission surface 14c as shown by the broken line in FIG.

Then, the linearly polarized light of the S-polarized light component emitted from the first entrance / exit surface 14b of the polarization beam splitter 14 enters the first reflection type display 17a, and the linear polarization light of the polarization beam splitter 14 The linearly polarized light of the P-polarized component emitted from the second entrance / exit surface 14c enters the second reflective display body 17b.

It should be noted that FIG. 1 shows a state in which the first diffraction grating element 5R of the diffraction grating laminate 4 is in an electric field-free state and an electric field is applied to the second and third diffraction grating elements 5G and 5B. Since the light emitted from the diffraction grating laminate 4 at this time is the red colored light R, it is emitted from the first entrance / exit surface 14b of the polarization beam splitter 14 and the first reflection type display. The light incident on the body 17a is the linearly polarized light Rs of the red S-polarized component, and the polarized beam splitter 14
The light emitted from the second incident / emission surface 14c and incident on the second reflective display body 17b is the linearly polarized light Ps of the red P-polarized component.

The linearly polarized light of the S-polarized light component incident on the first reflective display body 17a is set between the ordinary light and the extraordinary light by the λ / 4 retardation plate 27a on the front side of the reflective display body 17a. The linearly polarized light of the P-polarized light component, which has been given a phase difference of / 4 wavelength, becomes circularly polarized light, enters the reflective liquid crystal display element 18a, and enters the second reflective display body 17b. The λ / 4 retardation plate 27b on the front side of the display body 17b gives a quarter wavelength phase difference between the ordinary light and the extraordinary light, and becomes circularly polarized light and enters the reflective liquid crystal display element 18b.

On the other hand, the reflective liquid crystal display elements 18a of the first reflective display body 17a and the second reflective display body 17b,
18b is driven by the display element drive circuit 28,
Synchronous with the emission of the red, green, and blue colored lights R, G, and B from the diffraction grating laminate 4, the monochromatic image data of the colors of the colored lights are sequentially written.

That is, as shown in FIG. 1, when the red colored light R is emitted from the diffraction grating laminate 4, red monochromatic image data is written in the reflective liquid crystal display elements 18a and 18b, and the When the green colored light G is emitted from the lattice laminated body 4, the reflective liquid crystal display elements 18a and 18b are used.
When the green monochromatic image data is written in the, and the blue colored light R is emitted from the diffraction grating laminate 4, the red monochromatic image data is written in the reflective liquid crystal display elements 18a and 18b.

Then, the reflective liquid crystal display elements 18a, 18
As described above, the liquid crystal molecules 25a and the dye molecules 25b of the liquid crystal layer 25 absorb the light incident on the non-electric field pixels in the twist alignment state by the dye molecules 25b, respectively. Is the substrate 19,
The light incident on the electric field application pixel that is vertically oriented substantially vertically to the 20th surface is reflected by the reflection film 26, and the reflected light is emitted to the front side, and is the color of the incident light and the written single color. A monochromatic image corresponding to the image data is displayed.

These reflection type liquid crystal display elements 18a, 18
The light emitted from the electric field application pixel of FIG.
Incident on the reflection type display bodies 17a, 17b from the front side,
This is the reflected light of the light that has been circularly polarized by the λ / 4 phase difference plate 27b and has entered the reflective liquid crystal display elements 18a and 18b, and this emitted light (circularly polarized light) is the λ / 4 phase difference. After passing through the plates 27a and 27b again, a phase difference of ¼ wavelength is given between the ordinary light and the extraordinary light, and the first and second
The linearly polarized light in the polarization state in which the polarization plane is substantially rotated by 90 ° with respect to the linearly polarized light of the S-polarized component and the P-polarized component incident on the reflection type display bodies 17a and 17b from the front side thereof becomes the first linearly polarized light. First and second reflective display bodies 17a, 1
It is emitted to the front side of 7b.

That is, as described above, the light emitted from the first incident / emission surface 14b of the polarization beam splitter 14 and incident on the first reflective display body 17a is the linearly polarized light of the S polarization component. The polarization beam splitter 14
The light emitted from the second entrance / exit surface 14c and incident on the second reflective display body 17b is a linearly polarized light of the P-polarized component, and thus the light emitted from the first reflective display body 17a. Is the linearly polarized light of the P-polarized component, and the light emitted from the second reflective display body 17b is the linearly polarized light of the S-polarized component.

The linearly polarized light of the P-polarized component emitted from the first reflection type display 17a again enters the polarization beam splitter 14 from the first incident / emission surface 14b, and the reflection polarization layer 16 Through the exit surface 14d of the polarization beam splitter 14.

Further, the linearly polarized light of the S-polarized light component emitted from the second reflection type display 17b again enters the polarization beam splitter 14 from the second incident / emission surface 14c, and the reflection polarization layer 16 is formed. And is emitted from the emission surface 14d of the polarization beam splitter 14.

The exit surface 1 of this polarization beam splitter 14
The light emitted from 4d is the first reflection type display body 17a.
Monochromatic image light composed of linearly polarized light of P-polarized component emitted from the above and monochromatic image light composed of linearly polarized light of S-polarized component emitted from the second reflective display body 17b. The monochromatic image light is enlarged by the projection system 29 and projected on a projection surface such as a screen (not shown).

Then, the first and second reflection type display bodies 1
7a and 17b are sequentially emitted from the diffraction grating laminate 4 at a constant cycle (cycle of 20 msec to 30 msec),
The red, green and blue monochromatic images are sequentially displayed by reflecting the red, green and blue colored lights R, G and B which are sequentially incident on the reflection type display bodies 17a and 17b through the polarization beam splitter 14. Therefore, the first and second reflective display bodies 17 are provided.
The red, green, and blue monochromatic image lights that are sequentially emitted from a and 17b and projected by the projection system 29 are combined with a time difference to form a full-color image.

As described above, this projection display device comprises the light source 1 for emitting the white light W and the diffraction grating laminate 4.
Light extraction means for extracting the light of the light source 1 into a plurality of wavelength bands in a time division manner, first and second reflective display bodies 17a and 17b for generating image light from incident light, and extraction by the light extraction means. The separated light is further divided into two light fluxes and made incident on the first and second reflection type display bodies 17a and 17b, and the image light generated by the first and second reflection type display bodies 17a and 17b is combined. The polarization beam splitter 14 and the projection system 29 for projecting the image light combined by the polarization beam splitter 14 are provided, and color display is performed in a time division manner.

In this projection type display device, the light of the light source 1 is extracted by a light extracting means into a plurality of wavelength bands in a time division manner, and the lights of the extracted wavelength bands are separated by a polarization beam splitter 14 to obtain a first light beam. By making the light incident on the second reflective display bodies 17a and 17b,
17b to generate image light of colors of the plurality of wavelength bands,
The image light generated by the first and second reflective display bodies 17a and 17b is combined by the polarization beam splitter 14, and the combined image light is projected by the projection system 29, thereby performing time-division color display. Therefore, it is possible to project a small-sized color image with sufficient brightness.

That is, this projection type display device has the light source 1
The white light W from the incident light is made incident on the diffraction grating laminated body 4 to sequentially emit colored light of a plurality of colors from the diffraction grating laminated body 4, and the colored light is polarized by the polarization beam splitter 14 into one polarization component (S The light of the polarization component) and the light of the other polarization component (P polarization component) are separated and made incident on the first reflection type display body 17a and the second reflection type display body 17b, and the reflection type Each of the display bodies 17a and 17b emits monochromatic image light in a polarization state in which the polarization plane is rotated substantially 90 ° with respect to the incident light from the front side, to the front side, and both of the monochromatic image lights are emitted from the polarization beam splitter. The time of the monochromatic image light of a plurality of colors that are sequentially emitted from the first and second reflective display bodies 17a and 17b and projected by the projection system 29 by being superimposed by 14 and projected by the projection system 29. A color image by synthesizing is obtained so as to display on the projection surface such as a screen.

According to this projection type display device, the light source 1 is
Therefore, the entire device can be downsized, and colored lights of a plurality of colors are sequentially emitted from the diffraction grating laminate 4, and the colored lights of the same color are polarized by the polarization beam splitter 14. The first and second reflection type display bodies 17a and 17 are separated into the component light and the other polarized component light.
b of the reflection type display 17
Each of a and 17b emits monochromatic image light in a polarization state in which the polarization plane is substantially 90 ° rotated with respect to incident light from the front side to the front side, and both of the monochromatic image lights are output by the polarization beam splitter 14. Since the projections are made to overlap each other, the colored lights of a plurality of colors sequentially emitted from the diffraction grating laminate 4 are utilized with high efficiency with almost no waste, and the display of one reflection type display can be performed. It is possible to project a monochromatic image light having a sufficient brightness, which is approximately twice the brightness, and display a color image having a sufficient brightness on the projection surface by the time difference composition of the monochromatic image lights of a plurality of colors.

In this projection type display device, each of the first and second reflection type display bodies 17a and 17b reflects the incident light from the front side and emits the reflected light to the front side as described above. It is desirable that the reflection type display elements 18a and 18b for displaying a monochromatic image of the color of the wavelength band of the incident light and the phase difference plates 27a and 27b arranged on the front side of the reflection type display elements 18a and 27b are provided. Reflective display 17a, 17
By configuring b as described above, the monochromatic image light in the polarization state in which the polarization plane is substantially rotated by 90 ° with respect to the incident light from the front side of each of these reflection type display bodies 17a and 17b is supplied to the front side. Can be emitted.

In the above embodiment, the reflective display elements 18a and 18b of the first and second reflective display bodies 17a and 17b are used.
Is a GH type reflective liquid crystal display element that absorbs light incident from the front side when no electric field is applied, reflects the light incident from the front side when an electric field is applied, and outputs the light to the front side in the polarized state. Since 27a and 27b are λ / 4 phase difference plates that give a phase difference of ¼ wavelength between the ordinary ray of the transmitted light and the extraordinary ray, the light incident on the reflection type display bodies 17a and 17b from the front side thereof. Among them, most of the light incident on the non-electric field pixel is absorbed, and the light incident on the electric field applying pixel is reflected with a high reflectance and emitted to the front side, and most of the reflected light is changed to incident light from the front side. On the other hand, the light can be emitted as light having a polarization state in which the plane of polarization is substantially rotated by 90 °, and therefore, the first and second reflection type display bodies 17 are provided.
It is possible to make a color image which is brighter and has a good contrast by the time difference composition of the monochromatic image lights of a plurality of colors which are sequentially emitted from a and 17b and projected by the projection system 29.

Further, in the above-mentioned embodiment, the diffraction grating laminate 4 has the first diffraction grating element 5R which reflects or transmits the wavelength light in the red wavelength band when there is no electric field, and the green wavelength band which has the green wavelength band when there is no electric field. Since the second diffraction grating element 5G that reflects or transmits the wavelength light and the third diffraction grating element 5B that reflects or transmits the wavelength light in the blue wavelength band when there is no electric field are formed as a laminated body, the diffraction grating lamination Red, green, and blue colored lights R, G, and B are sequentially emitted from the body 4, and red, green, and blue single color images are sequentially displayed on the first and second reflective display bodies 17a and 17b, A full-color image can be displayed by time-difference synthesis of these monochromatic image lights.

The projection type display device of the above-described embodiment has the diffraction grating element 5R which transmits the wavelength light of the red wavelength band when there is no electric field and the diffraction grating element 5R which transmits the wavelength light of the green wavelength band when there is no electric field. 5G and a diffraction grating element 4 in which a diffraction grating element 5B that transmits wavelength light in the blue wavelength band when there is no electric field is laminated are provided, and the diffraction grating laminate has a red wavelength band when there is no electric field. From a laminated body of a diffraction grating element that reflects light of the wavelength, a diffraction grating element that reflects light of the green wavelength band when there is no electric field, and a diffraction grating element that reflects light of the wavelength band of blue when there is no electric field In that case, a polarization beam splitter may be arranged on the emission side of the diffraction light of the diffraction grating element.

FIG. 6 is a plan view of a projection type display device showing a second embodiment of the present invention. In this embodiment, the same components as those of the projection type display device of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The projection type display apparatus of this embodiment has a diffraction grating effect of reflecting the wavelength light R in the red wavelength band and transmitting the wavelength light in the other wavelength band when there is no electric field, and the diffraction by the application of an electric field. The first diffraction grating element 32R that loses the grating effect and reflects all wavelength light in the visible light band, and the wavelength light G in the green wavelength band when there is no electric field and reflects the wavelength light in other wavelength bands. The second diffraction grating element 32G, which has a diffraction grating effect, loses the diffraction grating effect by the application of an electric field and transmits all wavelength light in the visible light band, and reflects the wavelength light in the blue wavelength band when there is no electric field. A laminate with a third diffraction grating element 32B which has a diffraction grating effect of transmitting light of wavelengths in other wavelength bands, loses the diffraction grating effect by application of an electric field, and transmits light of all wavelengths in the visible light band A diffraction grating laminate 31 composed of Eteiru.

Incidentally, FIG. 6 shows a state in which the first diffraction grating element 32R of the diffraction grating laminated body 31 is in an electric field-free state and an electric field is applied to the second and third diffraction grating elements 32G and 32B. The diffraction grating laminate 3 is shown at this time.
Since the light emitted from No. 1 is the red colored light R, the light emitted from the first incident / emission surface 14b of the polarization beam splitter 14 and incident on the first reflective display body 17a is red S.
The linearly polarized light Rs of the polarization component, which is emitted from the second entrance / exit surface 14c of the polarization beam splitter 14 and enters the second reflective display body 17b, is the linearly polarized light of the red P polarization component. Ps.

In this embodiment, the diffraction grating laminated body 31 is disposed on the emission side of the light source 1 (the emission side of the condenser lens 3), and the incident surface thereof is substantially in the incident direction of the light from the light source 1. The polarization beam splitter 14 is arranged at an angle of 45 °, and the polarization beam splitter 14 is provided on the reflection light emitting side of the diffraction grating laminated body 31 and the incident surface 14a thereof is with respect to the reflection light emitting surface of the diffraction grating laminated body 31. It is arranged so that the reflected light emitted from the diffraction grating laminate 31 is incident on the incident surface 14a substantially perpendicularly by being inclined at an angle of about 45 °.

Also in the projection display apparatus of this embodiment, the white light W from the light source 1 is made incident on the diffraction grating laminated body 31, and the red, green and blue colored lights R, G, and
B is sequentially emitted, and the colored light is separated by the polarization beam splitter 14 into light of one polarization component (S polarization component) and light of the other polarization component (P polarization component), and
Of the reflection type display bodies 17a, 1 and the second reflection type display body 17b.
7b respectively emits monochromatic image light in a polarization state in which the polarization plane is rotated substantially 90 ° with respect to the incident light from the front side to the front side, and both of the monochromatic image lights are superposed by the polarization beam splitter 14. The projection system 29 projects the first and second reflection type display bodies 17
a, 17b, which are sequentially emitted and projected by the projection system 29 to display color images by time-difference synthesis of a plurality of monochromatic image lights of different colors on a projection surface such as a screen. In this case, the entire device can be downsized, and the red, green, and blue colored lights R, G, and B sequentially emitted from the diffraction grating laminate 31 can be used with high efficiency without being wasted. Then, by projecting a monochromatic image light having a sufficient brightness which is approximately twice the display brightness of one reflection type display body, a full color having a sufficient brightness is obtained by the time difference composition of the red, green and blue monochromatic image lights. The image can be displayed on the projection surface.

In the first and second embodiments described above,
The reflection type display elements 18a and 18b of the first and second reflection type display bodies 17a and 17b are GH type reflection type liquid crystal display elements of twist orientation, and the reflection type display elements are provided with electrodes, for example. The polymer / liquid crystal composite layer in which a plurality of liquid crystal layers in which the black dichroic dye is mixed is dispersed in the polymer layer is provided between the pair of front and rear substrates, and the outer or inner surface of the rear substrate is provided. It may be a reflective polymer dispersed liquid crystal display device having a reflective film provided on the inside thereof.

This reflective polymer dispersed liquid crystal display device absorbs light incident from the front side when the liquid crystal molecules and the dye molecules of the liquid crystal layer of the polymer / liquid crystal composite layer are oriented in random directions and no electric field is applied. When an electric field is applied in which liquid crystal molecules and dye molecules are oriented substantially perpendicular to the substrate surface, light incident from the front side is reflected in its polarized state and emitted to the front side, so a λ / 4 phase difference is applied to the front side. By arranging the plates to form a reflective display, most of the light that enters the electroless pixel out of the light that enters the reflective display from its front side is absorbed by the electric field application pixel. Is reflected at a high reflectance to be emitted to the front side, and most of the reflected light is emitted as light in a polarization state in which the polarization plane is substantially 90 ° rotated with respect to the incident light from the front side, and
The color image obtained by the time difference composition of the monochromatic image lights of a plurality of colors which are sequentially emitted from the second reflective display body and projected by the projection system can be made a brighter color image with good contrast.

Further, the first and second reflection type display bodies 17
The reflection type display elements a and 17b are not limited to the reflection type liquid crystal display element, and for example, a micromirror display element (Digital Mirror) in which a plurality of micromirrors tilting in one direction and the other direction are arranged in a matrix. Micromirror Devi
ce) may be used.
By arranging the / 4 phase difference plate to form the reflection type display body, most of the reflected light is emitted as light in a polarization state in which the polarization plane is rotated substantially 90 ° with respect to the incident light from the front side. be able to.

[0090]

According to the projection display apparatus of the present invention, a light source that emits white light, a light extraction unit that extracts the light of the light source into a plurality of wavelength bands in a time division manner, and an image light is generated from the incident light. The first and second reflection type display bodies, and the light extracted by the light extraction means is further divided into two light fluxes, which are made incident on the first and second reflection type display bodies. The beam splitter for synthesizing the image light generated by the reflection type display body, and the projection system for projecting the image light synthesized by the beam splitter are provided to perform color display in a time-division manner, and thus are small in size. Moreover, a color image with sufficient brightness can be projected.

Further, the projection type display device of the present invention emits white light from the light source and light of a wavelength in one wavelength band of the specific wavelength band of the visible light band and the other wavelength band when there is no electric field. A plurality of diffraction grating elements that have a diffraction grating effect of reflecting and transmitting wavelength light of the other wavelength band, losing the diffraction grating effect by application of an electric field and transmitting wavelength light of all wavelength bands of the visible light band The colored light beams of a plurality of colors are sequentially emitted from the diffractive grating layered product formed by stacking the colored light beams, and the colored light beams of one polarization component and the other polarized light component are output by the polarization beam splitter. The light is separated into light and made incident on the first reflective display body and the second reflective display body, and each of these reflective display bodies has a polarization plane substantially with respect to incident light from the front side thereof. Of the polarization state rotated 90 ° to Color image light is emitted to the front side, and both of the monochromatic image lights are overlapped by the polarization beam splitter and projected by a projection system, so that they are sequentially emitted from the first and second reflective display bodies and the projection is performed. The present invention is intended to display a color image by time-difference synthesis of monochromatic image lights of a plurality of colors projected by a system on a projection surface such as a screen. According to this projection display device, only one light source is required. It is possible to reduce the size of the whole, and moreover, use the colored lights of a plurality of colors sequentially emitted from the diffraction grating laminate with high efficiency with almost no waste, and display brightness of one reflective display body. It is possible to display a color image of sufficient brightness by projecting monochromatic image light of approximately twice the size and combining the monochromatic image lights of a plurality of colors with a time difference.

In the projection type display device of the present invention, each of the first and second reflection type display bodies reflects the incident light from the front side, emits the reflected light to the front side, and outputs the wavelength band of the incident light. A reflective display element for displaying a monochrome image of the color
It is preferable that the reflective type display device is configured by a retardation plate disposed on the front side of the reflective type display device. The polarization plane is substantially 9 with respect to the incident light.
The monochromatic image light in the polarization state rotated by 0 ° can be emitted to the front side.

In this case, the reflective display element has a liquid crystal layer in which a black dichroic dye is mixed, absorbs light incident from the front side when no electric field is applied, and absorbs light incident from the front side when an electric field is applied. Is a reflection type liquid crystal display device that reflects the light in its polarized state and emits it to the front side, and the retardation plate gives a phase difference of ¼ wavelength between the ordinary light of the transmitted light and the extraordinary light.
It is preferable to use a retardation plate, and by doing so, most of the light that enters the electroless pixel among the lights that enter the reflective display member from its front side are absorbed and enter the electric field application pixel. The light is reflected with a high reflectance and is emitted to the front side, and most of the reflected light is emitted as light in a polarization state in which the polarization plane is substantially 90 ° rotated with respect to the incident light from the front side, and It is possible to make a color image that is brighter and has a good contrast by a time difference composition of monochromatic image lights of a plurality of colors that are sequentially emitted from the first and second reflective display bodies and projected by the projection system. .

The diffraction grating laminate is a diffraction grating element that reflects or transmits wavelength light in the red wavelength band when there is no electric field, and a diffraction grating element that reflects or transmits wavelength light in the green wavelength band when there is no electric field. And a diffraction grating element that reflects or transmits wavelength light in the blue wavelength band when there is no electric field is desirable, and by doing so, red, green, and blue colored lights are sequentially output from the diffraction grating lamination. A full-color image can be displayed by causing the first and second reflection-type display bodies to emit a single color image in sequence and sequentially displaying red, green, and blue single color images, and combining these single color image lights with a time difference.

[Brief description of drawings]

FIG. 1 is a plan view of a projection type display device showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a part of a diffraction grating element that constitutes a diffraction grating stack.

FIG. 3 is an enlarged cross-sectional view of the diffraction grating element when no electric field is applied.

FIG. 4 is an enlarged sectional view of the diffraction grating element when an electric field is applied.

FIG. 5 is a sectional view of a part of a reflective display body.

FIG. 6 is a plan view of a projection type display device showing a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source 4, 31 ... Diffraction grating laminated body 5R, 5G, 5B, 32R, 32G, 32B ... Diffraction grating element 14 ... Polarization beam splitter 14a ... Incident surface 14b, 14c ... Incident / exit surface 14d ... Reflective display bodies 18a, 18b ... Reflective liquid crystal display elements 19, 20 ... Substrates 19 21, 22 ... Electrodes 23, 24 ... Alignment film 25 ... Nematic liquid crystal layer 26 mixed with dichroic dye ... Reflective films 27a, 27b ... λ / 4 retardation plate 29 ... projection system

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 9/31 H04N 9/31 CF term (reference) 2H049 AA43 AA50 AA60 AA65 BA05 BA07 BB03 BC22 2H088 EA14 EA16 GA13 HA10 HA15 HA17 HA20 HA21 MA02 MA05 2H091 FA10X FA11X FA14X FA14Z FA19X FA41X FD06 LA11 LA15 LA17 MA07 2K103 AA01 AA05 AB04 BC01 BC15 BC20 5C060 GA01 HC14 HC21 JA17

Claims (5)

[Claims] 1. A light source that emits white light, a light extraction means that extracts the light of the light source into a plurality of wavelength bands in a time division manner, and first and second reflective displays that generate image light from incident light. An image generated by the first and second reflection type display bodies by further separating the body and the light extracted by the light extraction means into two luminous fluxes and making them enter the first and second reflection type display bodies. A projection display device comprising a beam splitter for combining light and a projection system for projecting the image light combined by the beam splitter, and performing color display in a time division manner. 2. A light source that emits white light, and reflects a wavelength light in one wavelength band of a specific wavelength band and another wavelength band in the visible light band when there is no electric field, and reflects the wavelength light in the other wavelength band. A plurality of diffraction grating elements having a diffraction grating effect of transmitting wavelength light, losing the diffraction grating effect by application of an electric field and transmitting all wavelength light in the visible light band, and Diffraction grating laminates having different reflection / transmission wavelength bands when no electric field is applied to the grating element, and an incident surface, first and second incident / exit surfaces, and an exit surface, and light incident from the incident surface. Of the two polarization components orthogonal to each other, the light of one polarization component is emitted from the first input / output surface, the light of the other polarization component is output from the second input / output surface, and The light of the other polarization component incident from the input / output surface of 1 The polarization beam splitter that emits the light of the one polarization component that has entered from the input / output surface of 2 from the output surface and the incident light from the front side, and outputs the reflected light to the front side to First and second reflective display bodies that display a monochromatic image of a color in a wavelength band and emit light in a polarization state in which a polarization plane is substantially 90 ° rotated with respect to the incident light to the front side, A projection system for projecting light emitted from the first and second reflective display bodies, wherein the diffraction grating laminate is arranged on the emission side of the light source, and the reflection light and the transmitted light of the diffraction grating laminate are arranged. The polarization beam splitter is disposed on one of the exit sides with its entrance surface facing the diffraction grating stack, and the first and second polarization beam splitters are facing the first and second entrance / exit surfaces of the polarization beam splitter, respectively. And the second reflective display is placed Moni,
The projection type display device, wherein the projection system is arranged so as to face the emission surface of the polarization beam splitter. 3. The first and second reflective display bodies each reflect incident light from the front side and emit the reflected light to the front side to display a monochromatic image of a color in the wavelength band of the incident light. The projection display device according to claim 2, comprising a reflective display element and a retardation plate disposed in front of the reflective display element. 4. A reflective display element has a liquid crystal layer mixed with a black dichroic dye, absorbs light incident from the front side when no electric field is applied, and polarizes light incident from the front side when an electric field is applied. It is a reflective liquid crystal display element that reflects the light as it is and emits it to the front side. / 4
The projection display device according to claim 3, wherein the projection display device is a retardation plate. 5. A diffraction grating laminate comprising a diffraction grating element that reflects or transmits wavelength light in a red wavelength band when there is no electric field, and a diffraction grating element that reflects or transmits wavelength light in a green wavelength band when there is no electric field. The projection display device according to any one of claims 2 to 4, wherein the projection display device comprises a laminate with a diffraction grating element that reflects or transmits wavelength light in the blue wavelength band when there is no electric field.