JP2980372B2 - Optical writing type projection display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical writing type projection display, and more particularly, to input two-dimensional information such as an image and a data pattern to a spatial light modulation element using writing light, and to change display light. The present invention relates to an optical writing type projection display having a function of displaying this information two-dimensionally by using the information.

BACKGROUND ART Conventionally, the following devices have been known as optical writing type projection displays.

(1) Reference 1 (G. Marie: Ferroelectrics Vol. 10 (197
6) On p.9 to p.14), as shown in FIG.
DKDP (KD ₂ PO ₄ ) crystal 251, CaF ₂ holder 261, dielectric mirror 17, photoconductive layer 16, transparent electrode 15, and Peltier device in 1
An optically writable projection display with a configuration enclosed by 27 is shown. In FIG. 8, 6 is a lens, 28 is a polarizing beam splitter, 29 is a display light source, 30 is an object as an input image, 291 is an illumination light source for the object, 31 is input light, 12 is display light, and 13 is display light. Projection light, 33 is a power supply for driving the DKDP crystal 251 and the photoconductive layer 16, and 34 is a switch.

In the above configuration, the input light 31 emitted from the illumination light source 291 such as a xenon lamp or a halogen lamp reaches the photoconductive layer 16 through the lens 6 and the transparent electrode 15. In the photoconductive layer 16, the resistivity changes spatially according to the density of the input image. Therefore, when the driving power supply 33 connected to the pair of transparent electrodes 15 is opened and closed by the switch 34, a spatial change can be given to the electric field distribution applied to the DKDP crystal 251.
At this time, the applied electric field is converted into a spatial change in the refractive index by the electro-optic effect of the DKDP crystal. On the other hand, the display light source
The display light 12 emitted from 29 is polarized by the polarizing beam splitter 28, passes through the lens 6, passes through the CaF ₂ holder 261 in the vacuum vessel 241 and the transparent electrode 15, and illuminates the DKDP crystal 251.
The light is reflected by the dielectric mirror 17, follows the above-described optical path in the reverse direction, passes through the polarizing beam splitter 28, and is projected as projection light 13 on a screen (not shown).

(2) Reference 2 (Shigeru Yoshikawa, Masakatsu Horie, Hideo Takahashi, Fujo Shimura: IEICE Transactions, Vol. J59-C, No. 5 (1976) p.305)
Pp. 312), as shown in FIG. 9, shows a projection type display in which a dynamic scattering mode type nematic liquid crystal light valve 35 is closely attached to a cathode ray tube 3 having a fiber plate. In FIG. 9, 36 is a signal generator, 37 is a drive power supply for the liquid crystal light valve 35, 29 is a light source,
6 is a lens, 8 is an ultraviolet light cut filter, 9 is a mirror,
Reference numeral 12 denotes display light incident on the liquid crystal light valve 35, 13 denotes projection light, and 14 denotes a screen. In the above configuration, the light source
The light emitted from 29 passes through the lenses 6, 6, the ultraviolet light cut filter 8, and the mirror 9, becomes the display light 12, and further passes through the lens 6 to reach the liquid crystal light valve 35. The projection light 13 passing through the lens 6 from the liquid crystal light valve 35 is projected on the screen 14 to display an image.

Further, as shown in FIG. 10, the dynamic scattering mode type nematic liquid crystal light valve 35 is configured such that the transparent electrode 15, the translucent electrode 38,
This is an element in which a SeTe photoconductive layer 39, a wire plate 40, a spacer 41, a nematic liquid crystal 42, a transparent electrode 15, and a glass substrate 19 are sequentially adhered and integrally formed.

(3) Reference 3 (AGLedebuhr: SID86 Digest (1986) p.3)
79 to p. 382), as shown in FIG. 11, a CRT 3 having a fiber plate 2, a liquid crystal light valve 43 closely attached to the fiber plate 2, a polarizing beam splitter 44, and a dichroic filter 45. A projection display is shown. In FIG. 11, reference numeral 11 denotes an input line of an electric signal to be input to the cathode ray tube 3;
Is a light source, 48 is display light from a light source 47, 46 is a transparent plate for compensating the optical path length of blue light, 49 is an aperture, and 50 is 3
The projection light is modulated by the twisted nematic liquid crystal light valves 43.

In the above configuration, the display light 48 from the light source 47 passes through the mirror 9, the aperture 49, the mirror 9, and the lens 6, reaches the pair of polarizing beam splitters 44, 44, and further, the mirror 9, the lens 6, and the pair of dichroic filters. 3 by 45
Into three twisted nematic liquid crystal light valves 43. On the other hand, the projection light 50 modulated by the three twisted nematic liquid crystal light valves 43 is
The light is combined into one through a pair of dichroic filters 45, and further combined into a lens 6, a mirror 9, a polarizing beam splitter 44,
The image is projected on a screen (not shown) through the aperture 49, the mirror 9, the lens 6, and the mirror 9, and an image is displayed.

As shown in FIG. 12, the above-described liquid crystal light valve 43 closely adheres the alignment layer 51, the nematic liquid crystal layer 52, the alignment layer 51, the dielectric multilayer mirror 53, the light absorption layer 54, and the CdS photoconductive layer 55 in order, This is an element in which transparent electrodes 15 are attached to both ends to be integrally formed. In FIG. 12, reference numeral 41 denotes a nematic liquid crystal layer 52.
, 20 is an AC power supply connected to the transparent electrode 15, 19 is a glass substrate adhered to the sides of both transparent electrodes 15,
31 is input light, 12 is display light incident on the liquid crystal light valve 43, and 13 is projection light.

(4) Reference 4 (J. Trias, W. Robinson and T. Phillips: SI
D88 Digest (1988) p.99-p.101), as shown in FIG. 13, writing light 57 from an argon ion laser 56 is incident on a twisted nematic liquid crystal light valve 43 through a beam scanner 58, while Projection in which the display light 12 from the xenon light source 4 is incident on the other surface of the liquid crystal light valve 43 through the polarization beam splitter 44, and the projection light 13 reflected therefrom is projected through the projection lens 6 onto a screen (not shown). A type projector is shown. In FIG. 13, reference numeral 59 denotes an input electric signal, and 60 denotes an electric circuit for driving the beam scanner 58 according to the input electric signal 59.

(5) Reference 5 (Y. Mori, Y. Nagae, E. Kaneko, H. Kawakami,
T.Hashimoto and H.Shiraishi: Displays April (1988)
As shown in Fig. 14, semiconductor lasers
The writing light 62 from 61 is incident on the smectic liquid crystal light valve 65 through the XY scanner 64, while the light 12 from the xenon light source 4 is incident on the other surface of the liquid crystal light valve 65 through the dichroic mirror 66. A projection display that projects the reflected light on the screen 14 through the projection lens 67 and displays the image is shown. In FIG. 14, 68 is a liquid crystal light valve drive circuit, 66 'is a wavelength filter, 69 is an f-.theta. Lens, 63 is a collimating lens, 70 is a polarizing prism, 71 is a beam splitter, and 72 is an XY scanner. , 73 is a system control circuit, and 74 is a semiconductor laser drive circuit.

As shown in FIG. 15, the above smectic liquid crystal light valve 65 has a transparent electrode 15, an alignment layer 51, and a smectic liquid crystal layer.
75, an alignment layer 51, a metal mirror 76, and a heat absorbing layer 77 are sequentially adhered to each other, and a glass substrate 19 provided with an antireflection film 78 on the outside is provided on both sides thereof.

However, the above-mentioned conventional optical writing type projection display has the following drawbacks.

(1) In the projection type display of Document 1 shown in FIG. 8 of the above item (1), since the electro-optic effect of the DKDP crystal 251 is used, (1-1) polarization such as the polarization beam splitter 28 is used. A plate and an analyzer plate are required, so the display light 12 utilization rate is 50%
It becomes below.

(1-2) When the spectrum width of the display light 12 is wide, the contrast is reduced.

(1-3) Resolution can be improved by making DKDP crystal 251 thinner, but there is a limit to thinning bulk single crystal by polishing (currently
(About 100 μm), which makes it difficult to increase the resolution.

(1-4) It is difficult to obtain a large-area DKDP crystal 251.

(1-5) Due to the disadvantages of (1-3) and (1-4), it is difficult to display a high-definition image.

(1-6) The DKDP crystal 251 is reduced by −50 using the Peltier device 27.
It is necessary to cool to about ° C, which complicates the configuration.

(1-7) There are disadvantages such as a large driving voltage. For this reason, the display of Document 1 is not suitable for displaying a high-resolution image.

(2) In the projection display of Document 2 shown in FIGS. 9 and 10 in the above item (2), a dynamic scattering mode type nematic liquid crystal is used in the light valve 35. Response speed is extremely slow.

(2-2) Since the liquid crystal is driven by current, power consumption is large and the element life is short.

(2-3) There are drawbacks such as low contrast of the displayed image. For this reason, the display of Document 2 is not suitable for displaying moving images.

(2-4) In addition, since the wire plate 40 is used, there is a problem that the resolution is low.

(3) In the projection type display of Document 3 shown in FIGS. 11 and 12 in the above item (3), the birefringence of the twisted nematic liquid crystal is utilized by the liquid crystal light valve 43. ) The display has the same drawbacks as (1-1), (1-3) and (1-4) of the display described in the above item (1).

(3-2) Further, it is necessary to make the thickness variation of the liquid crystal layer about ± 50 nm over the entire liquid crystal layer, and it is practically extremely difficult to manufacture the liquid crystal light valve 43 having a large area and excellent uniformity. is there.

(3-3) There is a problem that the response of the liquid crystal and the CdS photoconductive layer is slow. For this reason, the display of Document 3 is not suitable for displaying a high-resolution moving image.

(4) In the projection type display of Document 4 shown in FIG. 13 of the above item (4), the same liquid crystal light valve 43 as the display of the above item (3) is used. It has the same problems as (3-1), (3-2), and (3-3) of the display described in the above item (3).

(4-2) Further, the writing light source 56 and the beam splitter 44 become large.

(4-3) Since the writing light 57 is two-dimensionally scanned by the traveling wave lens (chirped grating lens) utilizing the acousto-optic effect in the beam scanner 58,
There is a problem that high-order diffracted light exists around the condensed spot and the resolution is reduced. For this reason, the display of Literature 4 is not suitable for displaying a high-resolution moving image.

(5) In the projection type display of Document 5 shown in FIGS. 14 and 15 in the above item (5), the writing light 62 is scanned on the smectic liquid crystal light valve 65, and the writing light 62 is scanned.
Using the thermal energy of the liquid crystal, the smectic liquid crystal in the liquid crystal light valve 65 is changed from a homogeneous state to a scattering state,
The operation principle of transmitting or scattering the display light 12 is used.

(5-1) Therefore, although the resolution is high, the response speed is extremely slow. For example, it takes several tens of seconds to about one minute to display one still image.

(5-2) It is difficult to display halftones, that is, it is difficult to achieve full color.

(5-3) There is a problem that a highly accurate beam scanner 64 is required. For this reason, the display of Literature 5 is not suitable for displaying moving images.

DISCLOSURE OF THE INVENTION Therefore, an object of the present invention is to solve various problems as described above, and to display a high-quality and bright image, display of a data pattern, light wavelength conversion, and particularly to a coherent light image of an incoherent light image. It is an object of the present invention to provide a light-writing type projection display which can perform high-speed conversion or inverse conversion thereof and is suitable for displaying a high-resolution moving image on a large screen.

In order to achieve the above object, the present invention provides a liquid crystal and a transparent resin matrix having a refractive index equivalent to one of the ordinary refractive index, the extraordinary refractive index, and the refractive index when the liquid crystal is randomly aligned. A liquid crystal composite in which one of the liquid crystals is dispersed and confined to the other, a dielectric multilayer mirror that totally reflects all or a part of the visible light spectrum, and light transmitted through the dielectric multilayer mirror A spatial light modulator having a structure in which an insulating light absorbing layer for absorbing light and a photoconductive layer are laminated in this order, and a transparent electrode is disposed on both sides of the liquid crystal composite and the photoconductive layer; Having a display element for converting the light image into a light image having a spectrum sensitive to the photoconductive layer, means for making the light image incident on the spatial light modulator, and a visible light source for emitting white light; Light modulation Means for irradiating the white light as display light to a child, has an aperture, characterized by comprising an imaging optical system for imaging projected light emitted from the spatial light modulator.

Here, the display element may be a cathode ray tube.

The cathode ray tube is a cathode ray tube having a fiber plate as its image display surface, and the fiber plate and the spatial light modulator are brought into close contact with each other through a transparent liquid layer having a value close to the refractive index of the fiber plate. be able to.

The display device is a liquid crystal television device, and the liquid crystal television device is illuminated with light having a spectrum sensitive to the photoconductive layer of the spatial light modulator, and the transmitted light of the liquid crystal television device is converted to the light. Light can be incident on the conductive layer.

The optical path of display light incident on the spatial light modulator is different from the optical path of projection light reflected by the dielectric multilayer mirror in the spatial light modulator when an electric field is applied to the spatial light modulator. A schlieren optical system that takes an optical path can be provided.

The liquid crystal can be a nematic liquid crystal, a cholesteric liquid crystal or a smectic liquid crystal.

Another embodiment of the present invention is directed to a liquid crystal and a transparent resin matrix having a refractive index equivalent to one of an ordinary refractive index, an extraordinary refractive index, and a refractive index when the liquid crystal is randomly aligned. A liquid crystal composite composed of one of them dispersed and confined to the other, a dielectric multilayer mirror that totally reflects all or part of the visible light spectrum, and absorbs light transmitted through the dielectric multilayer mirror First, second, and third spaces each having a structure in which an insulating light absorbing layer and a photoconductive layer are stacked in this order, and transparent electrodes are disposed on both sides of the liquid crystal composite and the photoconductive layer, respectively. The light modulation element and the blue, green and red input image signals are respectively
The photoconductive layer includes first, second, and third display elements that convert the light image into a light image having a spectrum that is sensitive to the light image, and converts the light image into the first, second, and third spatial light modulation elements, respectively. A first light having a blue or near blue spectrum, and a second light having a green or near green spectrum.
And a third light having a red or near-red spectrum, respectively,
Means for irradiating the first and second and third lights as display light to second and third spatial light modulators, respectively;
An imaging optical system having an aperture and imaging the projection light emitted from the first, second, and third spatial light modulators to display a full-color image.

Here, the first, second and third display elements can be cathode ray tubes.

The cathode ray tube is a cathode ray tube having a fiber plate as an image display surface, and is connected to the fiber plate through the transparent liquid layer having a value close to the refractive index of the fiber plate. The spatial light modulator can be closely attached.

The first, second, and third display elements are liquid crystal television devices, and each of the first, second, and third spatial light modulation elements has light having a spectrum that is sensitive to the liquid crystal television device. By irradiating the device, light transmitted through the liquid crystal television device can be incident on each of the photoconductive layers.

The optical path of each display light incident on the first, second and third spatial light modulators and the first and second spatial light modulators when an electric field is applied to the first, second and third spatial light modulators. And a schlieren optical system that takes an optical path different from the optical path of the projection light reflected by the dielectric multilayer mirror in the third spatial light modulator.

The liquid crystal can be a nematic liquid crystal, a cholesteric liquid crystal or a smectic liquid crystal.

Since the present invention is configured as described above, high-quality and bright images and display of data patterns, light wavelength conversion,
In particular, it is possible to convert an incoherent light image into a coherent light image or vice versa at a high speed, which is suitable for displaying a high-resolution moving image and enables a large screen.

(A) That is, the response speed (several milliseconds to ten and several milliseconds) of the liquid crystal composite constituting the present invention is higher than that of a dynamic scattering mode liquid crystal or a twisted nematic liquid crystal. Therefore, the projection display of the present invention has a faster response speed than the conventional projection display described in the above items (1) to (5), and is suitable for displaying moving images.

(B) Since the projection type display of the present invention utilizes the light scattering characteristics by applying a voltage to the liquid crystal composite, an image can be displayed without using a polarizing plate and an analyzer. Therefore, according to the present invention, a bright display image is obtained, the space of the display image is excellent in uniformity, the contrast is high, and the drawbacks unique to the conventional projection display described in the above item (1) are: That is, the display light utilization rate is poor, the advanced crystal processing technique is required, the contrast is reduced, the display light is parallel, and the like, and the drawbacks unique to the conventional projection display described in (3) above. That is, the problem of poor display light utilization and difficulty in increasing the area, and the disadvantages of the conventional projection display described in the above item (4), ie, the problem of poor display light utilization and the writing light source, etc. It does not have the problem of the large scale of.

(C) The spatial light modulation element constituting the present invention requires a liquid crystal alignment layer indispensable for the liquid crystal light valve of the conventional projection display described in the above items (1), (3) and (4). In addition, since the liquid crystal layer of liquid is not sandwiched between the substrates, the device can be easily manufactured even if the display screen is enlarged.

(D) Further, the liquid crystal composite constituting the present invention is significantly different from a conventional liquid crystal cell in which a liquid crystal is sealed inside by sealing the periphery of the substrate (see FIGS. 10 and 12). For example, by using an amorphous silicon film for the photoconductive layer, it is possible to easily increase the size of the spatial light modulation element, and it is difficult to match the size with existing cathode ray tubes. Are better.

(E) The transmittance-applied voltage characteristic of the liquid crystal composite constituting the present invention has a smaller γ characteristic than that of a twisted nematic liquid crystal or a ferroelectric liquid crystal, so that an analog image can be displayed easily. Also suitable for analog display.

(F) In the present invention, a compact projection type display can be configured by using, for example, a liquid crystal television device instead of the cathode ray tube.

(G) The present invention also has an advantage that a moving image can be displayed using a schlieren optical system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of the configuration of an optical writing type projection display according to the present invention, and FIG. 2 is a perspective view showing an example of the configuration of a spatial light modulator as a component in FIG. 3 (A) and 3 (B) are perspective views showing the operation of a liquid crystal composite as a component of the spatial light modulator of FIG. 2, and FIGS. 4 to 7 are optical writing projections of the present invention, respectively. FIGS. 8 to 15 are schematic views showing another configuration example of a liquid crystal display, and FIGS. 8 to 15 show a configuration of a conventional light-writing type projection display described in Documents 1 to 5, respectively, and a spatial light modulator as a component thereof. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 schematically shows the configuration of an embodiment of the optical writing type projection display according to the present invention. In FIG. 1, 1
Is a spatial light modulator, which is described in detail with reference to FIG. 2, 2 is a fiber plate, 3 is a CRT, and 3 is a CRT.
The image display surface glass is replaced with a fiber plate 2, and the spatial light modulator 1 is adhered to the fiber plate 2 via a transparent liquid layer. The cathode ray tube 3 converts an electric signal from the input line 11 into an optical image having a spectrum to which a photoconductive layer in the spatial light modulator 1 is sensitive.

Reference numeral 4 denotes a display light source as a visible light source that emits white light, for example, a xenon lamp, a halogen lamp, a metal halide lamp, or the like. White light from the display light source 4 having the concave reflecting mirror 5 passes through the condenser lens 6, the infrared cut filter 7, the ultraviolet cut filter 8, and the visible light filter 8 ', and changes the optical path by the reflecting mirror 9 to change the lens 6'. As described above, the spatial light modulator 1
Incident on. The lenses 6 ′, 6 ″ and the aperture 10 constitute an image forming optical system, and the projection light 13 emitted from the spatial light modulator 1 is transmitted through the lenses 6 ′, 6 ″ and the aperture 10.
The image is projected on a screen 14 through 10 to display an image. Further, reference numeral 20 denotes an AC power supply for the spatial light modulator 1.

FIG. 2 shows a detailed configuration example of the spatial light modulator 1 of the embodiment of FIG. As shown in FIG. 2, the spatial light modulator 1 of this embodiment includes a transparent electrode 15, a photoconductive layer 16, a dielectric multilayer mirror 17 for totally or partially reflecting the visible light spectrum, An element in which an insulating light-absorbing layer 170 for absorbing light transmitted through the multilayer mirror 17, a liquid crystal composite 18, an electrode 15, and a glass substrate 19 are successively adhered and integrated.
An AC power supply 20 is connected to the two transparent electrodes 15. Between the transparent electrode 15 attached to the photoconductive layer 16 and the fiber plate 2, a transparent liquid (layer) having a refractive index of the fiber plate 2, a refractive index of the transparent electrode 15, or a refractive index between the two. ) 21 is inserted.

The fiber plate 2 is integrated with the cathode ray tube 3. That is, one surface of the fiber plate 2 is configured to be inside the cathode ray tube, and the other surface is configured to be in contact with the liquid layer 21.

As shown in FIGS. 3A and 3B, the liquid crystal composite 18 used in the present invention includes a nematic liquid crystal, a cholesteric liquid crystal, or a smectic liquid crystal 22, and an ordinary refractive index and an extraordinary refractive index of the liquid crystal. And a transparent resin matrix 23 having a refractive index equivalent to either the refractive index or the refractive index when the liquid crystal is randomly oriented. The liquid crystal 22 is dispersed and confined in the resin matrix 23.

That is, in the liquid crystal composite 18 of the present invention, the liquid crystal 22 in the resin matrix 23 is indefinite as shown in FIGS. 3A and 3B (the length is several hundred nanometers to several micrometers).
In which the liquid crystal 22 is encapsulated in a resin matrix 23 in a microcapsule state or in which the resin matrix 23 is dispersed and enclosed in the liquid crystal 22 (not shown). is there.

In the liquid crystal composite 18 having such a configuration, when the ordinary light refractive index or the extraordinary refractive index of the liquid crystal 22 substantially matches the refractive index of the resin matrix 23, in a state where no electric field is applied to the liquid crystal composite 18, However, since the refractive indices of the liquid crystal 22 and the resin matrix 23 are different from each other, light is scattered, and on the other hand, when the electric field is applied to the liquid crystal composite 18, the refractive indices of the liquid crystal 22 and the resin matrix 23 are almost equal. They are in a transmission state in which the light is transmitted. In addition, when the refractive index when the liquid crystal 22 is randomly aligned and the refractive index of the resin matrix 23 are substantially the same, the refractive index of the liquid crystal 22 and the resin matrix 23 when no electric field is applied to the liquid crystal composite 18. Since the ratios match, it becomes a transmission state where light is transmitted,
On the other hand, when an electric field is applied to the liquid crystal
The refractive index of the resin matrix differs from that of the resin matrix, resulting in a scattering state in which light is scattered. In the present invention, both of these types of liquid crystal composites 18 can be used, but the type in which the ordinary or extraordinary refractive index of the liquid crystal 22 and the refractive index of the resin matrix 23 are almost the same is more preferable. preferable. In particular, liquid crystal 22
The type in which the ordinary light refractive index substantially matches the refractive index of the resin matrix 23 is optimal in terms of its performance.

Photoconductive layer used in the present invention shown in FIG. 2 and FIG.
16 is, for example, CdS, CdSe, Se, SeTe, GaAs, GaP, Bi ₁₂ SiO ₂₀ , Bi
_It is made of a material such as ₁₂ GeO ₂₀ , Si, hydrogenated amorphous silicon film, amorphous selenium film, etc., whose impedance is greatly reduced by light irradiation. The impedance of the photoconductive layer 16 at the time of writing light irradiation and at the time of non-irradiation of writing light are Z _ON and Z _OFF , respectively, and the impedance of the liquid crystal composite 18 and the combined impedance of the dielectric multilayer mirror 17 and the light absorbing layer 170 _Assuming that Z _LC and Z _M , respectively, the spatial light modulator 1 used in the present invention has the relationship of the following equation (1).

Z _OFF > Z _LC > Z _ON >> Z _M (1) The thickness and dielectric constant of the photoconductive layer 16 are t ₁ and ε ₁ , and the thickness and dielectric constant of the liquid crystal composite 18 are t ₂ and ε ₂ , Further, when the total thickness and the dielectric constant of the dielectric multilayer mirror 17 and the light absorbing layer 170 are defined as t ₃ and ε ₃ , respectively, the spatial light modulator 1 used in the present invention has the relationship of the following equation (2). Having.

Next, the optical writing type projection according to the embodiment of the present invention in the case of using the spatial light modulation element 1 including the liquid crystal complex 18 of the type in which the ordinary light refractive index of the liquid crystal 22 and the refractive index of the resin matrix 23 are almost the same. The operation of the type display will be described.

When the electric signal input through the input line 11 in FIG. 1 is zero, the light emission intensity of the cathode ray tube 3 is zero, and most of the voltage applied to the spatial light modulator 1 according to the equation (1) is photoconductive. The voltage applied to the liquid crystal composite 18 applied to the layer 16 is small.
Accordingly, the molecules of the liquid crystal 22 are oriented in various directions according to the irregular wall surfaces of the resin matrix 23 as shown in FIG. LCD 22 at this time, the refractive index of the resin matrix 23 surrounding the liquid crystal 22 (n _p) and different refractive index ^{_{{(2n o + n e 2}} ) / 3}
^{Has 0.5} . Therefore, the display light 12 in FIG.
8, the intensity of the projection light 13 is minimized.

Next, when the electric signal input through the input line 11 increases, as shown in FIG. 3B, the fluorescent light 21 'on the surface of the cathode ray tube 3 increases according to the level of the electric signal. This fluorescent light 21 ′ is transmitted through the fiber plate 2 to the photoconductive layer 16.
To reduce the impedance of the photoconductive layer 16. Therefore, the voltage applied to the liquid crystal composite 18 increases. When the level of the input electric signal of the input line 11 is sufficiently large, the long axis of the liquid crystal molecules of the liquid crystal composite 18 is shown in FIG.
As shown, since oriented at all applied field display light 12 incident substantially perpendicular to the liquid crystal composite 18, the refractive index n _p is n _o n _p of the ordinary refractive index n _o and the resin matrix 23 of the liquid crystal 22 In this case, the light passes through the liquid crystal 22 without being scattered, is reflected by the dielectric multilayer mirror 17, and the intensity of the projection light 13 is maximized.

At this time, the image projected on the screen 14 is a bright and large-area enlarged optical image emitted from the cathode ray tube 3, and can have an arbitrary spectrum by the visible light filter 8 '. The contrast and brightness of the image projected on the screen 14 are adjusted by the aperture 10 for performing a field stop. That is, the aperture
Increasing the aperture of 10 increases the brightness of the projected image on screen 14, but decreases its contrast. On the other hand, when the aperture of the aperture 10 is reduced, the screen 14
The contrast of the upper projected image improves, but its brightness decreases.

FIG. 4 shows another configuration example of the optical writing type projection display according to the present invention. The display of FIG. 4 is a full-color projection display using three sets of the cathode ray tube having the basic configuration shown in FIG. In FIG. 4, reference numeral 24 denotes a dichroic light which reflects white light 12 from a visible light source, blue light or light having a spectrum close to blue light (hereinafter referred to as blue light) 12B, and transmits other light. It is a mirror. Reference numeral 25 denotes light that transmits green light or light having a spectrum close to green light (hereinafter referred to as green light) 12G to visible light transmitted through the dichroic mirror 24, and has red light or a spectrum close to red light ( This is a dichroic mirror that reflects 12R.

Reference numerals 1B and 3B in FIG. 4 denote a spatial light modulator and a Braun tube corresponding to the blue light 12B, and have a function of modulating the blue light 12B and converting it into blue projection light 13B. Also, 1R and 3R are a spatial light modulator and a cathode ray tube corresponding to the red light 12R, and convert the red light 12R to the red projection light 13R.
It has the function of converting to. Further, 1G and 3G are a spatial light modulator and a Braun tube corresponding to the green light 12G, and have a function of converting the green light 12G into green projection light 13G. The projection light 13B, 13R, 13G for each color is combined by the dichroic mirrors 24, 25 to form one projection light 13,
The image is projected and displayed on the screen 14.

FIG. 5 shows still another configuration example of the optical writing type projection display according to the present invention. In the configuration shown in FIG. 5, the dichroic mirrors 24 and 25 are removed from the configuration shown in FIG.
Instead, four dichroic prisms 26 are provided. In FIG. 5, the light incident on the spatial light modulators 1B, 1G, and 1R and the light emitted therefrom are simplified so as to pass through the same optical path, but in reality, 12B and 13B in FIG. 12G
And 13G, and slightly different optical paths like 12R and 13R.

Further, as an optical writing type projection type display of the present invention, an image of a conventional general cathode ray tube 3 'is spatially modulated by using a lens 6 as shown in FIG. 6 instead of the cathode ray tube with a fiber plate of FIG. A configuration in which an image is formed on the element 1 is also possible. Similarly, in the configuration of the embodiment shown in FIGS. 4 and 5, instead of the CRT with a fiber plate, a conventional general CRT 3 'and a lens 6 are used.
Can be used.

Further, as the optical writing type projection display of the present invention, it is possible to use a liquid crystal television device 80 as shown in FIG. 7 instead of the cathode ray tube shown in FIG. In FIG. 7, reference numeral 81 denotes writing light having a spectrum that effectively produces the photoconductive effect of the photoconductive layer 16 constituting the spatial light modulator 1. Also, as shown by the broken line in the figure, if the second aperture 10 ′ is inserted between the lens 6 and the spatial light modulator 1 and the writing light 81 is made coherent light, an unnecessary image of the liquid crystal television 80 can be obtained. (For example, an image in which a matrix wiring or a thin film transistor circuit itself is projected on a screen), and only an original television image can be written into the spatial light modulator 1, thereby achieving high quality projection without image unevenness. It is also possible to obtain images.

4 and 5, it is also possible to construct a projection display using the liquid crystal television 80 and the imaging lens 6 instead of the CRT with a fiber plate.

In the projection type display of the embodiment of the present invention shown in FIG. 1, FIG. 4, FIG. 5, FIG. 6, or FIG. 7, the display light 12 and the projection light 13 have different optical paths. A schlieren optical system is employed. Although the conventional projection display of FIGS. 9 and 14 using the Schlieren optical system only displays a still image, the projection display of the present invention can display both a still image and a moving image. There are features. Also, a half mirror (not shown) is provided in place of the reflection mirror 9 in FIGS. 1, 4, 5, 6, and 7, and display light is provided.
Of course, it is also possible to make the optical path of 12 and the projection light 13 coincide.

As a specific example, a 0.5 mm thick B
i ₁₂ SiO ₂₀ crystal, ₂₀ μm thick liquid crystal composite 18 of cyanobiphenyl nematic liquid crystal and acrylic resin, 70 nm thick transparent electrode 15 and 1 mm thick transparent glass substrate 19
As a result of configuring the display shown in FIG. 7 using the spatial light modulator 1 composed of, a good projected image was obtained as expected. In addition, as the liquid crystal television device 80 of FIG. 7, a 5 inch black and white pocket type liquid crystal television device facing each other is used, and as the light source 4, a 1KW xenon lamp is used.
As the visible light filter 8 ', a visible light filter for blocking light having a wavelength shorter than 560 nm was used. Experiments have also confirmed that the apparatus of this embodiment is suitable as a projection type display, and further projects a 1.4 mx 1.1 m moving image on the screen 14 to be suitable as a large screen display.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the following specific effects can be obtained.

(1) Since the light-writing type projection display of the present invention does not require a polarizer and an analyzer, a display image is almost twice as bright as a projection display using a conventional polarizer and analyzer.

(2) Since the alignment treatment as in the case of the liquid crystal used in the conventional spatial light modulator is not required and the large-area spatial light modulator can be easily manufactured, it is bright with high resolution and large area. Can be easily displayed.

(3) Since the birefringence and optical rotation of the liquid crystal are not used, the display image has less unevenness.

(4) It is not necessary to increase the parallelism of the display light incident on the spatial light modulator, and a bright display image can be obtained because the light emitting area of the display light source may be relatively large.

(5) The response of the projection display of the present invention is faster than that of a conventional light-writing projection display using a spatial light modulator composed of a twisted nematic liquid crystal or a dynamic scattering mode liquid crystal. That is, the total rise and fall time of the spatial light modulator used in the present invention is from several milliseconds.
It is about 10 milliseconds, which is much shorter than the total rise and fall times (about 50 milliseconds to several hundred milliseconds) of the conventional optical writable spatial light modulator using twisted nematic liquid crystal.

(6) Since the spatial light modulator used in the present invention has input / output light characteristics with a small value of γ, it is suitable for analog light modulation. On the other hand, the value of γ of a projection type display using a conventional optical writing type spatial light modulation element is large and is not suitable for analog light modulation.

(7) A moving image can be displayed using the schlieren optical system.

Claims (12)

(57) [Claims] 1. A liquid crystal, a transparent resin matrix having a refractive index equivalent to one of an ordinary refractive index, an extraordinary refractive index of the liquid crystal, and a refractive index when the liquid crystal is randomly aligned, and one of the liquid crystal. A liquid crystal composite composed of the other dispersed and confined, a dielectric multilayer mirror that totally reflects all or part of the visible light spectrum, and an insulating layer that absorbs light transmitted through the dielectric multilayer mirror. A spatial light modulator having a structure in which a light absorbing layer and a photoconductive layer are stacked in this order, and a transparent electrode is disposed on both sides of the liquid crystal composite and the photoconductive layer; A display element for converting the light image into a light image having a sensitive spectrum, means for causing the light image to be incident on the spatial light modulation element, and a visible light source for emitting white light; Show light Means for irradiating a has an aperture, an optical writing type projection display, characterized by comprising an imaging optical system for imaging projected light emitted from the spatial light modulator. 2. An optical writing type projection display according to claim 1, wherein said display element is a cathode ray tube. 3. The cathode ray tube according to claim 1, wherein the cathode ray tube has a fiber plate as an image display surface. The cathode ray tube is connected to the fiber plate via a transparent liquid layer having a value close to the refractive index of the fiber plate. The optical writing type projection type display according to claim 2, wherein the element is brought into close contact with the element. 4. The liquid crystal television device, wherein the display element is a liquid crystal television device, wherein the liquid crystal television device is illuminated with light having a spectrum sensitive to the photoconductive layer of the spatial light modulator. The optical writing type projection display according to claim 1, wherein transmitted light is incident on the photoconductive layer. 5. An optical path of display light incident on the spatial light modulator, and a projection light reflected by the dielectric multilayer mirror in the spatial light modulator when an electric field is applied to the spatial light modulator. The optical writing type projection display according to any one of claims 1 to 4, further comprising a schlieren optical system having a different optical path from the optical path. 6. The optical writing type projection type display according to claim 1, wherein said liquid crystal is a nematic liquid crystal, a cholesteric liquid crystal or a smectic liquid crystal. 7. A liquid crystal, a transparent resin matrix having a refractive index equal to one of the ordinary light refractive index, the extraordinary light refractive index of the liquid crystal, and the refractive index when the liquid crystal is randomly oriented, and one of the liquid crystals. A liquid crystal composite composed of the other dispersed and confined, a dielectric multilayer mirror that totally reflects all or part of the visible light spectrum, and an insulating layer that absorbs light transmitted through the dielectric multilayer mirror. First, second, and third spatial light modulators each having a structure in which a light absorbing layer and a photoconductive layer are laminated in this order, and transparent electrodes are disposed on both sides of the liquid crystal composite and the photoconductive layer, respectively. And a first, a second, and a third display element for converting a blue, green, and red input image signal into a light image having a spectrum to which the photoconductive layer is sensitive, respectively, The first, second and A means for causing the light to enter the third spatial light modulator, a first light having a visible light source, and a first light having a spectrum close to blue or blue, and a second light having a spectrum close to green or green. Optical means for separating light and third light having a spectrum close to red or near red, respectively, the first and second spatial light modulators to the first, second and third spatial light modulators;
Means for irradiating the first and second light as display light, respectively; and an imaging optical system having an aperture and imaging the projection light emitted from the first, second and third spatial light modulators. And a full-color image is displayed. 8. The light-writing type projection display according to claim 7, wherein said first, second and third display elements are cathode ray tubes. 9. The cathode ray tube, wherein the cathode ray tube has a fiber plate as an image display surface, wherein the cathode plate is connected to the fiber plate via a transparent liquid layer having a value close to the refractive index of the fiber plate. An eighth aspect of the present invention, wherein the second and third spatial light modulators are brought into close contact with each other.
The optical writing type projection display according to the paragraph. 10. The liquid crystal television device according to claim 1, wherein said first, second and third display elements have a spectrum which is sensitive to each photoconductive layer of said first, second and third spatial light modulators. 8. The optical writing type projection display according to claim 7, wherein the liquid crystal television device is irradiated with the light, and light transmitted through the liquid crystal television device is incident on each of the photoconductive layers. 11. An optical path of each display light incident on said first, second and third spatial light modulating elements, and said optical path when an electric field is applied to said first, second and third spatial light modulating elements. 9. The schlieren optical system according to claim 7, further comprising a schlieren optical system in which the optical path of the projection light reflected by said dielectric multilayer mirror in said first, second and third spatial light modulators takes a different optical path. Item 11. The optical writing projection display according to any one of Item 10. 12. The optical writing type projection display according to claim 7, wherein said liquid crystal is a nematic liquid crystal, a cholesteric liquid crystal or a smectic liquid crystal.