JPS5974530A - Method for picture display - Google Patents

Abstract

PURPOSE:To attain high-resolution pictures, by heating a liquid layer consisting of a liquid, which is light-transmittable for visible rays, in accordance with picture information in such degree that the liquid layer is not boiled and changing the refractive index of the liquid by heating and changing the optical path of the light to make a picture apparent. CONSTITUTION:When radiant light 6a is irradiated to a display element DE from the right in a figure, a corresponding point of a radiant light absorbing layer 6 is heated, and a liquid layer 2 close to the layer 6 is heated to form a high- temperature heated part 13 in the liquid layer 2, and an illuminating light 4 passing through this part 13 has the optical path changed. A part of the illuminating light which has the optical path changed in this manner passes through the aperture of a grating 7 when it is emitted from the display element DE, and all of the illuminating light which does not pass through the heated part 13 is intercepted by the grating 7; and therefore, the display element DE is seen through the grating 7, the illuminating light 4 passing through the heated part 13 and the illuminating light 4 passing a non-heated part are distinguished from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel image display method, display element, and display device.

Currently, cathode ray tubes (so-called CRTs) are widely used as terminal displays in various office equipment and measuring instruments, or as displays in televisions and video camera monitors. However, dissatisfaction remains with this CRT in that its image quality, resolution, and display capacity do not reach the level of hard copies made using silver halide or electrophotography. In addition, as an alternative to CRT, attempts have been made to put so-called liquid crystal panels into practical use that display dot matrix images using liquid crystals.
Nothing satisfactory has yet been achieved in terms of driveability, reliability, productivity, and durability.

Therefore, an object of the present invention is to solve the problems that could not be solved by the conventional techniques in this technical field.

In other words, the objects of the present invention are a method of displaying high-resolution and high-quality images, a novel display element that has excellent drive performance, productivity, durability, and reliability and has high density pixels, and a display device using the same. The purpose is to provide

Embodiments of the display of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic cross-sectional view for showing the image forming principle of the display element according to the present invention. FIG. 1(A) shows a transmissive display element DE, and FIG. 1(B) shows a reflective type The display elements DE are shown respectively. Reference numeral 1 denotes a heat generating element that changes the physical properties of the liquid layer 2 made of a liquid that is transparent to visible light and heats the liquid layer 2 to an extent that boiling does not occur in the liquid layer 2. As will be described later, this heating element 1 heats the liquid layer 2 by heat conduction by generating heat in various forms such as a dot matrix shape (a dotted line shape), a dot line shape (a dotted line shape), a line shape, and an island shape. .

Examples of the heat generating element l include those that utilize radiation heating, which will be described later, and those that utilize Joule heat such as resistance heating. When the display element DE is a transmissive type,
The heating element l is required to be transparent to visible light. Reference numeral 2 denotes a liquid layer made of a liquid that is transparent to visible light, and the basic composition of this transparent liquid is water or various organic solvents used alone or in combination. Examples of various organic solvents used for this include methyl alcohol,
Alkyl alcohol such as ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5ec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, etc. Alcohol; For example, hydrocarbon solvents such as hexane, octane, cyclopentane, benzene, toluene, and quidylole; For example, halogenated hydrocarbon solvents such as carbon tetrachloride, trichloroethylene, tetrachloroethylene, tetrachloroethane, and dichlorobenzene; For example, ethyl ether,
Ether solvents such as butyl ether, ethylene glycol diethyl ether, and ethylene glycol monoethyl ether; Ketone solvents such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl amyl ketone, and cyclohexanone; ethyl formate, methyl acetate, propyl acetate, and phenyl acetate. , ester solvents such as ethylene glycol monoethyl ether acetate; alcohol solvents such as diacetone alcohol; amides such as dimethylformamide and dimethylacetamide; amines such as triethanolamine and jetanolamine; Examples include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, and alkylene glycols; polyhydric alcohols such as glycerin; petroleum hydrocarbon solvents, and the like. The thickness of the liquid layer 2 is preferably within the range of 1 μm to 1+am.

3 is a transparent protective plate, which is made of transparent (colorless to light-colored) glass or plastic that is as pressure resistant as possible. Note that this protective plate may not be used when the display element DE is arranged horizontally. 5 is a substrate, and in the case of the transmissive display element DE shown in FIG. In the case of the reflective display element DE shown in FIG. 1(B), a member having pressure resistance is used. Although the heat generating element 1 is provided on the substrate 5, the heat generating element 1 and the substrate 5 may be used in common, and in particular, the heat generating element may not require the substrate 5. Basically, the substrate 5, the heat generating element 1, the liquid layer 2, and the transparent protection plate 3 are laminated in this order to constitute the display element DE according to the present invention. Reference numeral 4 denotes illumination light that is incident on the display element DE in the form of parallel light, which is natural light or light from a light source (not shown), and is incident on both the non-heating section and the heating section 1a of the heat generating element 1. 13 is a liquid layer heating part, which is a high temperature area formed by heating a part of the low temperature area of the liquid layer 2 with a heating element 1 to an extent that it does not boil;
For example, it shows the part of the liquid layer 2 heated by the heating part 1a where the heating element 1 generates heat, and in reality, the temperature gradient force (
In some cases, the refractive index of the liquid in the liquid layer 2 in this part is different from the refractive index before heating by the heat generating element l (however, the liquid layer 2 is preheated by the heat generating element 1). In this case, the state force of the preheated liquid layer causes the liquid layer heating section 13 to
Since the layer 2 is further heated to form the liquid layer 2, the refractive index C± of the formed liquid layer heating section 13 is further changed from the refractive index of the liquid layer 2 in the preheated state. ).

Assume that the temperature of the translucent liquid in the liquid layer 2 rises from t° C. to (t+Δt)TN due to heat generated by the heating portion 1a of the heat generating element 1. In this case, if the refractive index of the translucent liquid at temperature t°C is N, and the refractive index at temperature (t+Δt)'c is N+ΔN, then the refractive index gradient is ΔN/Δ.
”(1/”C,). The rate of change in the refractive index, that is, the change in refractive index with respect to temperature t-* (M force), is the heating part 1
When the small, J\ region of the liquid layer 2 near a is heated strongly, the refractive index gradient in the small region is larger than l, and therefore, the liquid layer force in this heated small region is have,
The light C± is refracted in a region with a large refractive index gradient (gradient intensity). Furthermore, △N/Δt f
i#i is not necessarily a negative value (l,).

The heating portion 1a of the heat generating element 1 generates heat and is heated to such an extent that the translucent liquid of the liquid layer 2 does not boil and its physical properties change as described above, thereby forming the liquid layer heating portion 13. Since the other parts t± of the heating element 1 do not generate heat, the physical properties of the liquid layer 2 in the corresponding low temperature region hardly change, and the physical properties are approximately uniform. Even in the low-temperature region, it is actually heated by heat conduction from the heating section, etc., and the optical properties t± will change, but this will be relatively negligible from the viewpoint of the change in the heating section. Liquid layer 2 of display element DE
The illumination light 4t incident on a source other than the liquid layer heating section 13 travels straight within the liquid layer 2 and emerges from the display element DE as parallel light. Of course, at this time, in the case of a transmissive display element DE, the illumination light 4 enters from the back surface force of the display element DE, and then enters the display element D.
Inject from the front side of E.

That is, the illumination light 4 is emitted through the substrate 5 → heat generating element 1 → liquid layer 2 (low temperature region) → transparent protection plate 3. Further, in the case of a reflective display element DE, the illumination light 4 enters from the front surface of the display element DE along the path t± and exits from the front surface. That is, illumination light 4
is transparent protection plate 3 → liquid layer 2 (low-temperature region) → reflected on the surface of heat-generating element l (if heat-generating element l is non-reflective, it is reflected by a light-reflective reflective film (not shown)) → liquid layer 2 (low-temperature region) )→The light is emitted from the display element DE through the transparent protection plate 3. On the other hand, the path of the illumination light 4 passing through the liquid layer heating section 13 which is a high temperature region of the liquid layer 2 passes through the liquid layer heating section 13 described above except for passing through the liquid layer heating section 13 within the liquid layer 2. Display element DE of illumination light 4 that does not
The route is exactly the same. However, the illumination light 4 passing through the liquid layer heating section 13 does not travel straight through the liquid layer 2 but is refracted and changes its optical path due to a refractive index gradient (gradient index) thermally generated in this section. Therefore, the illumination light 4 that passes through the liquid layer heating section 13 and the illumination light 4 that does not pass through it do not become parallel light when they exit the display element DE, and their exit directions are different from each other. When the heating part 1a of the heat generating element 1 stops heating, the liquid layer heating part 13
is cooled and disappears, and the direction of all the illumination light 4 emitted from the display element DE becomes the same direction as the light that has passed through the portion other than the liquid layer heating section 13. Therefore, the illumination light 4 that passes through the high temperature region of the liquid layer heating section 13 and the illumination light 4 that passes through the low temperature region of the liquid N2 located outside the liquid layer heating section 13 are optically distinguished. The display element OE according to the present invention is capable of direct viewing under certain illumination conditions (for example, illumination with parallel light), but can be further used as a display device by combining with an imaging optical system to be described later. Value expands. In the case of the former direct-view display, the favorite display pixel can be identified based on the difference in the amount of light that reaches an observing eye (not shown) positioned with respect to the direction of the light that has passed through the liquid layer heating section 13. In the case of the latter combination of display element DE and an imaging optical system described below, the imaging position of the liquid layer heating section 13 of the liquid layer 2 by the imaging optical system and the heating element other than the liquid layer heating section 13 of the liquid layer 2 The imaging position by the imaging optical system of the low-temperature region portion of the liquid layer 2 that is not heated by the heating element l (including the case where the liquid layer 2 is preheated by the heating element l) (hereinafter referred to as the liquid layer non-heated part) Since the display points are different, the display points can be more clearly identified by defocusing. Therefore, by defocusing, a bright spot can be inverted and displayed as a dark spot. When the imaging optical system described below is not used, parallel light is used as the illumination light 4 to increase the display effect of the display element DE, and the display effect can be dramatically improved by adding a light-shielding grating as described below. .

In Fig. 1, the heat generating element l is in direct contact with the liquid layer 2 to heat the liquid layer 2, but the heat generating element l is placed near the liquid layer 2 and heats the liquid layer 2 by thermal conduction heating. You may.

For example, in FIG. 1B, if the heat generating element 1 does not reflect light, a light reflective metal film, dielectric mirror, etc. is interposed between the liquid layer 2 and the heat generating element 1.

In addition, in this example, in order to make the explanation easier to understand, the light beam incident on the display element DE is assumed to be parallel light, but the light beam incident on the display element DE is not limited to parallel light. The liquid layer heating section 13 in the high temperature region of the liquid layer 2 is formed in the optical path due to the heat generated by the heating section 1a of the heating section 1, thereby changing the optical path compared to the optical path before the liquid layer heating section 13 was not formed. It uses

FIG. 2 is a schematic cross-sectional view of a display element for more specifically explaining the image forming principle of the display element according to the present invention, and FIG. 2(A) shows a transmissive display element DE. Figure (B) shows reflective display elements DE.

In the figure, 6 is a radiation absorption layer that absorbs radiation 6a and generates heat, 2 is a liquid layer, and 3 is a transparent protective plate. Basically, the display element DE is constructed by laminating these layers. has been done. In the reflective display element DE shown in FIG. 2(B), 9 is a pressure absorbing film that absorbs the increase in pressure when the liquid layer 2 is heated, and 8 is a pressure absorbing film used for display. illumination light 4
10 is a heating layer for preheating the liquid layer 2. These reflective film 8, pressure absorbing film 9, and heat generating layer 10 are not necessarily required for the display element DE, and are used as necessary. for example,
When the liquid layer 2 is heated, the pressure absorbing film 9 is not used in the display element DE where the internal pressure of the liquid layer 2 does not increase significantly, and the reflective film 8 is not used when the radiation absorbing layer 6 has light reflectivity. The liquid layer 2 is not used, and the boiling point of the liquid in the liquid layer 2 is low, so the heat generation of the radiation absorbing layer 6 only by irradiation of the radiation 6a to the radiation absorbing layer 6 heats the liquid layer 2 with sufficient responsiveness, and the liquid layer is heated. When the portion 13 is formed, the heating element layer 10 is not used. However, since the heat generating layer 10 will be described later, the description will be made assuming that the heat generating layer 10 is not present in FIG. 2(B). Further, the pressure absorbing film 9 and the heat generating layer 10 are also used in the transmission type display element DE shown in FIG. 2(A), if necessary. The radiation absorbing layer 6 efficiently absorbs radiation 6a, especially infrared rays, and generates heat.
It is difficult to melt by itself due to heat generation. This radiation absorbing layer 6 is obtained by forming a film (including a multilayer film) of various inorganic or organic materials. Since the radiation absorbing layer 6 itself has a film thickness of only a few liters, it generally lacks a supporting function, so it is common to add a radiation-transparent support plate as a substrate made of glass, plastic, etc. (not shown). be. The translucent liquid constituting the liquid layer 2 is of the types described above, and generally refers to a liquid that is translucent to visible light, and the translucent liquid is transparent to radiation 6a such as infrared rays. It does not matter whether it is translucent or not. Reference numeral 7 denotes a grating which, when the liquid layer 2 is not heated, enters the display element DE and transmits the light to the transmissive display element DE.
The illumination light 4 that passes through the display element DE or is reflected by the display element DE of one reflection type and exits from the display element DE is blocked.

When the display element DE configured as described above is irradiated with radiation (especially infrared rays) 6a from the right side of the drawing, corresponding points on the radiation absorption layer 6 generate heat. When a portion of the radiation absorbing layer 6 generates heat in this manner, the liquid in the liquid layer 2 that is in contact with or in the vicinity of this portion is heated by thermal conduction.
As the temperature of the liquid increases, its refractive index changes from before heating, and a liquid layer heating section 13 in the high temperature region of the liquid layer 2 is formed.

When the illumination light 4 passing through the liquid layer heating section 13 passes through the liquid layer heating section 13, its optical path is changed by the mechanism described above in FIG. At least a portion of the illumination light 4 that has undergone this optical path change passes through the opening of the grating 7 when exiting the display element DE. On the other hand, since all the illumination light 4 that does not pass through the liquid layer heating section 13 is blocked by the grating 7,
When viewing the display element DE through this grid 7, illumination light 4 passing through the part of the liquid layer 2 where the liquid layer heating part 13 is formed and illumination light 4 passing through the liquid layer non-heating part of the liquid layer 2 is identified.

Of course, if the illumination light 4 passing through the non-heated part of the liquid layer is made to pass through the opening of the grid 7, the illumination light 4 passing through this part will be blocked by the grid 7 when the liquid layer heating part 13 is formed. Since the light is blocked, there is also an opening in the grating 7 through which the illumination light 4 does not pass, and a display element having the reverse form of the above-mentioned embodiment is also possible.

Even if there is no grating 7, the direction of the illumination light 4 passing through the liquid layer heating section 13 and the direction of the illumination light 4 passing through the liquid layer non-heating section of the liquid layer 2 are as follows: Since they are different from each other, the illumination light 4 can be optically distinguished when viewed in the direction in which either one of the light beams comes.

Note that when irradiating the display element DE with the radiation 6a,
It is possible to irradiate in a pattern corresponding to a predetermined image, or it is possible to use a laser light source to irradiate a large number of beams at once in a dot shape using the radiation 6a as a beam. Alternatively, a method of scanning one line beam over the radiation absorbing layer 6 can also be used.

Furthermore, the direction in which the radiation 6a is irradiated is not limited to the illustrated example in the case of the transmissive display element DE shown in FIG. 2(A). In other words, the transparent protection plate 3 and the liquid layer 2 are exposed to radiation 6.
In the case where the radiation 116a is transmitted, it is also possible to irradiate the radiation 116a from the left side of the drawing. Note that the display is naturally erased by cooling the liquid layer heating section 13. This point differs from the conventionally known thermo-optic effect of liquid crystals. In other words, the thermo-optical effect of liquid crystals changes from a transparent state to an opaque state, or vice versa, due to thermal changes, but once the changed state is memorized, it cannot return to its original state simply by returning the temperature to its original state. (Because the molecular arrangement is confined). However, liquid crystals are also within the technical scope of the present invention as long as they are used within the scope of the principle of the present invention, that is, the optical properties are thermally reversible. This is because the use of such liquid crystals has not been previously known.

Although the method for forming display pixels by radiation heating has been described above, in the present invention, the radiation absorbing layer 6 in FIG. It is also possible to make a modification so that a heating element (not shown) is brought into close proximity to or in contact with this to heat the liquid by conduction.

In the present invention, in order to further enhance the discrimination effect of display pixels, visible light reflection II*8 can be separately interposed between the radiation absorption layer 6 and the liquid layer 2 as described above. The reflective film 8 needs to be formed of a high melting point metal material or metal compound material that does not melt itself during heat conduction.

In order to obtain an effective display in the present invention, the radiation absorbing layer 6
Although it is necessary to heat the liquid surface of the liquid layer 2 in contact with the liquid layer 2 and the liquid layer 2 in the vicinity thereof, it is not a requirement that the heating extends to the liquid surface of the liquid layer 2 in contact with the transparent protection plate 3 and the vicinity thereof. .

However, the liquid layer 2 in contact with the heating surface of the radiation absorbing layer 6
The liquid level and the temperature of the liquid layer 2 in the vicinity are
Experiments have shown that the higher the temperature is, the higher the display contrast of the display element DE is. Furthermore, if this is actively utilized, it becomes possible to display intermediate tones by varying the amount of heat for heating the liquid layer 2.

Incidentally, the smaller the irradiation spot diameter for irradiating the radiation 6a onto the radiation absorption layer 6, the better the display contrast will be.The spont diameter (diameter) of the radiation 6a is suitably about 0.5 square to 1 OIL.

However, a display image can be obtained even if the radiation absorbing layer 6 is irradiated with the radiation 6a of a rectangular light beam having a width of 2IIlffl and a length of 10 mm. The term "liquid layer heating section 13" often used in the detailed description of the present invention includes the latter range. However, even if the liquid layer heating part 13 of the liquid layer 2 is not very small, the temperature of the heating surface is not uniform, so the direction of the optical path of the light in the liquid layer heating part 13 and the direction of the light in the non-heated part of the liquid layer are different. A discrimination effect will occur if there is a difference in the direction of the light path. Therefore, in the present invention, the liquid layer heating section 13 is not limited to a minute range.

In the present invention, since the boiling point device 2 of the liquid constituting the liquid layer 2 is not heated, no vapor bubbles are generated and no sudden pressure increase occurs.

Therefore, damage to the display element DE due to the above-mentioned pressure does not pose much of a problem. However, it should be assumed that the pressure of the display element DE will increase, albeit slightly, due to the heating of the liquid layer 2, and that bubbles may be generated in the event of some kind of unavoidable vehicle accident. There will be a need.

Therefore, in preparation for such a case, it is desirable to connect this liquid layer 2 to an air chamber or an accumulator (not shown) to alleviate the increase in pressure in the liquid layer 2. or,
As another method, as shown in FIG. 2(B), the display element D
A pressure absorbing membrane 9 is placed in E between the liquid layer 2 and the transparent protection plate 3.
By intervening, the pressure generated in the liquid layer 2 may be absorbed.

Of course, it is even more effective to use the two methods described above together. The pressure absorbing membrane 9 is made of a translucent elastic material or a highly viscoelastic material, and may also be made of a so-called sponge that contains air bubbles or has ventilation holes.

Furthermore, if air bubbles made of room temperature gas are generated or mixed into the liquid layer 2, a means for removing such air bubbles is required. You could even let it hold up.

As another means, air bubbles can be removed by pressure or suction using a pump or syringe (not shown).

In this embodiment, as shown in FIG. 2 CB), in order to greatly speed up the formation speed of the liquid layer heating portion 13 as a display pixel, when the reflective film 8 is not used, the display element DE A heating element layer lO that generates heat by Joule heat is provided between the radiation absorption layer 6 and the liquid layer 2, or when the reflection film 8 is used, between the radiation absorption layer 6 and the reflection film 8, and It is desirable to preheat the liquid layer 2. At this time, if the radiation absorbing layer 6 or the reflective film 8 is a conductor, it is desirable to provide an insulating layer (not shown) between them and the heat generating layer 10.

As such a heating element layer 10, it is preferable to use a dowel, a linear heating element corresponding to a radiation beam, or a plurality of scanning lines, a grid heating element (none of which is shown), or the like. heating element layer 10
In the case where the heating element is a linear heating element, the heating portion is minute in the width direction, so it is thought that good display results can be obtained.

At this time, it is preferable to synchronize the irradiation of the radiation 6a to the radiation absorbing layer 6 and the heating of the liquid layer 2 by the heating element layer 10. Examples of the material for such a heating element layer 1O include metal compounds such as hafnium boride and tantalum nitride, and alloys such as nichrome.

Furthermore, in the present invention, a structure of the display element DE in which a corrosive component comes into direct contact with the liquid layer 2 should be avoided, since this will shorten the life of the element DE. In other words, in a configuration where a corrosive component is in contact with the liquid layer 2,
Chemical corrosion, thermal oxidation, etc. often occur, causing damage or deterioration of the display element DE.

Therefore, in such a case, it is desirable to form a corrosion-resistant protective film (not shown) at the interface between the liquid layer 2 and the corrosive component6.The material for this protective film is silicon oxide. , dielectric materials such as titanium oxide, heat-resistant plastics, and the like.

In the present invention, of course, the reflective film 8 may also serve as this protective film depending on its function.

Note that when a metal or the like is used as the radiation absorbing layer 6, it is generally formed into a film on a radiation transparent support plate as a substrate, so when the radiation absorbing layer 6 is heated, , there is no need to worry about it being acetylated by external air. If the radiation absorption rate of the radiation absorption layer 6 is not perfect, the absorption rate of the radiation 6a of the radiation absorption layer 6 can be reduced by applying an antireflection film (not shown) on the side to which the radiation 6a is irradiated. can also be significantly increased.

Next, as an application example, a light valve type projection device will be explained with reference to FIGS. 3 to 9. A light valve is a device that controls or adjusts light. Therefore, light from an independent light source is controlled by a suitable medium (in this example, the liquid layer of the display element) and projected onto the screen. All displays that use projection display are included in this category. Compared to self-luminous displays such as cathode ray tubes, this method can theoretically increase the size and brightness of the display screen by increasing the intensity of the light source used, so it is especially suitable for large screen displays that require a large amount of light. suitable for Among them, the one shown in Figure 3 is also called a schlieren light valve, which creates patterns with different refraction angles, diffraction angles, or reflection angles of light in a liquid layer, which is a control medium, according to an input signal. This method uses an optical system to convert the changes into bright and dark images, which are then projected onto a screen.

FIG. 3 is a schematic configuration diagram for explaining the basic principle of the display device. The images of each slit of the first grating 7a are arranged so as to be formed on each bar of the second grating 7b by a schlieren lens 11 so as to be shielded from light.

If the liquid layer as a medium of the transmission type display element DE placed between the Schlieren lens 11 and the second grating 7b is not heated and its refractive index is uniformly smooth, the first grating 7a All the incident light that has passed through is blocked by the second grating 7b4 and does not reach the screen 12. When a part of the liquid layer of the display element DE is heated by the heating element and reaches a high temperature, a liquid layer heating part 13 is formed and the refractive index changes, and the optical path of the light passing there changes as described above. Therefore, the incident light 14 that has passed there reaches the screen 12 through the gap (opening) of the second grating 7b without being blocked by the second grating 7b. Therefore, if the imaging lens 11' is arranged so that the heating surface heating the liquid layer heating section 13 of the display element DE or the medium surface in the vicinity thereof is imaged on the screen 12, the liquid layer of the display element DE can be heated. A bright and dark image corresponding to the amount of temperature change is obtained on the screen 12. Note that the openings of the first and second gratings 7a and 7b used for this are linear,
It does not matter whether it is dotted or not. 4 and 5 are schematic configuration diagrams of modified embodiments of the display device of FIG. 3. In FIG. 4, reference numeral 14' denotes a light source, which is placed at the focal point of the lens lla, so all light beams from this point on pass through the lens lla and become parallel beams. This parallel light beam enters as incident light 14 from the back surface of the transmissive display element DE. 7C is a light-shielding filter, which is placed at the focal point of the condensing lens llb, so if the refractive index of the liquid layer of the display element DE is uniform, the incident light 14 passes through the display element DE as it is and is condensed. The light is focused on the light shielding filter 7c via the lens llb. As a result, the incident light 14 does not reach the screen 12 placed behind the light blocking filter 7c at all. but,
When a part of the liquid layer of the display element DE is heated to a high temperature and a liquid layer heating part 13 is formed and the refractive index there changes, the optical path of light passing through that part of the display element DE changes as described above. Therefore, the incident light 14 that has passed there reaches the screen 12 without being blocked by the light blocking filter 7C.

Therefore, if the condenser lens llb is arranged so as to image the heating surface heating the liquid layer heating section 13 of one display element DE, or the medium surface in the vicinity thereof, on the screen 12, the liquid layer of the display element DE can be heated. A bright and dark image corresponding to the amount of temperature change is obtained on the screen 12.

FIG. 5 is a schematic diagram of a modification of the display device of FIG. 4 for obtaining an inverted image. 14' is a light source placed at the focal point of lens lla, flb is a condensing lens, and light source 14' is made into a parallel beam by lens lla.
This is for condensing the incident light 14 from the lens to a focal position. A light shielding filter 7d is arranged at the focal point of the condenser lens llb, which passes only the light beam passing through the focal point, that is, the focal point. In addition, the condenser lens llb and the light shielding filter 7
A transmissive display element DE is arranged between 7d and a screen is arranged behind the light shielding filter 7d. When the liquid layer heating section 13 is not formed in the transmissive display element DE, the incident light 14 is all condensed to a condensing point by the condensing lens llb, passes through this condensing point, and reaches the screen 12. do. However, when the liquid layer heating section 13 is formed in the display element DE, the light passing through this section changes its optical path and becomes scattered light.
The screen 1 is blocked by the light blocking filter 7d.
There are points on 2 where the light does not reach, forming a bright and dark image.

FIG. 6 is a schematic diagram of a modified embodiment of the display device of FIGS. 4 and 5. FIG. The light beam from the light source 14' is made into parallel light by the lens lla, and the light beam is turned into parallel light by the half mirror 1.
The incident light 14 enters the reflective display element DE via the light beam 5'. if.

If the refractive index of the liquid layer of the display element DE is uniform, the incident light 14 on the display element DE is reflected by the display element DE,
Like the incident light 14, this reflected light is parallel light and is condensed at a condensing point via a condensing lens llb. If the light-blocking filter 7C (in this case, the light-blocking filter 7d is not arranged) is arranged at this light-converging point, the light focused at this light-converging point will be blocked by the light-blocking filter 7C and will not reach the screen 12. .

However, when a part of the liquid layer of the display element DE is heated to form a liquid layer heating part 13 in a high temperature region and the refractive index there changes, the light incident on this part changes its optical path and is reflected.
The light reaches the screen 12 via the condenser lens llb. If this condensing lens llb is arranged at a position where it images the heating surface heating the liquid layer heating section 13 or the medium surface in the vicinity thereof on the screen 12, the temperature of the liquid layer of the display element DE A bright and dark image corresponding to the amount of change is obtained on the screen 12.

In addition, in order to obtain an inverted image on the screen, a light shielding filter 7d, also indicated by a chain line, is arranged as shown in the figure, instead of the light shielding filter 7C, which allows light to pass through only the condensing point indicated by a chain line. do it. In this case, most of the scattered light from the liquid layer heating section 13 of the display element DE is blocked by the light blocking filter 7d, and the non-scattered light passes through the light blocking filter 7d and reaches the screen 12-H, so that the above-mentioned inversion is possible. An image is obtained.

FIG. 7 is a schematic diagram of a transmission type light valve type projection device, and shows an example of the arrangement of signal input means for a transmission type display element DE. 7a is a first grating, DE is a transmission type display element, 11 is a schlieren lens, 7b is a second grating, 11' is an imaging lens, and 12 is a screen, and these structures are similar to the configuration of the display device in FIG. Similar.

The signal light of the radiation (mainly infrared rays) 6a modulated through a laser light source and a light modulator (not shown) is horizontally scanned by a rotating polygon mirror serving as a horizontal scanner 17, and is scanned horizontally by a rotating polygon mirror serving as a horizontal scanner 17, and then transmitted through a lens lie and then being rotated as a vertical scanner 16. It is vertically scanned by a polygon mirror or a galvano mirror, reflected by a cold filter 15, and focused on the radiation absorbing layer 6 of the transmission type display element DE shown in FIG. Liquid layer heating section 13 by heating in matrix form
A two-dimensional image is formed. On the other hand, since the incident light 14 that has passed through the first grating 7a passes through the cold filter 15, the incident light 14 passes through the screen 12 by the mechanism described above in FIG.
A two-dimensional visible image corresponding to the liquid layer heating section 13 of the display element DB is formed thereon. It goes without saying that the radiation absorbing layer 6 of the display element DE used in this figure must be transparent to visible light.

Note that semiconductor laser arrays or light emitting diode arrays (
If the horizontal scanner 17 is used, the horizontal scanner 17 is omitted. Further, the cold filter 15 and the galvanometer mirror may be used in common.

Note that the transmission type display element DE shown in FIG. 2(A) is
When applied to FIGS. 5 to 5, for example, the laser oscillator, horizontal scanner 17, lens lie, vertical scanner 16, cold filter 15, etc. described in FIG. 7 may be used for the incident method of the radiation 6a. At this time, the cold filter 15 is located between the display element DE and the lens lla in FIG. 4, and between the display element DE and the lens lla in FIG.
It is sufficient if it is interposed between the display element DE and the condenser lens ttb.

FIG. 8 is a schematic diagram of a reflective light pulp type projection device as a display device. The light beam from the light source 14' is converted into parallel light through the lens lla, and this parallel light is further bent at a right angle by the mirror 18 and enters the condenser lens llb. The incident light 14 for illumination focused by the condensing lens llb passes through the central aperture provided at the center of the mirror 19 and is again converted into parallel light by the lens llc, resulting in the reflection shown in FIG. 2(B). type display element DE (here, excluding the heating element layer IO). This incident light 14 is reflected by the reflective film 8 of the display element DE, but the reflected light (all or Most of it) exits through the central opening of the mirror 19 via the lens lie again. On the other hand, some of the light reflected at the display point of one display element DE goes out from the central opening of the mirror 19, but is reflected by the mirror 19.

An image is formed on the screen 12 by the imaging lens 11.

Further, the signal light of radiation (mainly infrared rays) 6a modulated through a laser light source and an optical modulator (not shown) is horizontally scanned by a rotating polygon mirror serving as a horizontal scanner 17, and passed through a lens lle as a vertical scanner 16. The radiation is vertically scanned by a galvanometer mirror and is two-dimensionally scanned and incident on the radiation absorption layer 6 of the display element DE. As a result, a large number of display points are formed two-dimensionally within the display element DE in accordance with the signal light, and as described above, these display points are formed as cut points on the screen 12 as a projection image and are projected. An image will be obtained.

Of course, the reflective display element DE shown in FIG. 2(B) can be used in the display device shown in FIG. 6 as in FIG.

FIG. 9 is a brochure diagram of a light valve type projection device as a display device according to the present invention.

25 is a video generation circuit that generates a video signal; 24 is a control circuit that controls the video signal and supplies this signal to the video amplification circuit 22 and the horizontal and vertical drive circuits 23; 21 is a laser light source; and 20 is a laser light source. The light modulated by the optical modulator 2o, which modulates the laser beam according to the signal from the video amplification circuit 22, enters the horizontal scanner 16 or the vertical scanner 17. Further, the horizontal scanner 16 and the vertical scanner 17 operate in response to drive signals synchronized with the video signals from the horizontal and vertical drive circuits 23, respectively. The configuration of the other portions within the broken line is the same as the configuration described above, so the description thereof will be omitted.

The video signal output from the video generation circuit 25 is sent to the control circuit 2.
4 and is amplified by the video amplification circuit 22. The optical modulator 20 is driven by the input of the amplified video signal and modulates the laser beam emitted from the laser light source 21. on the other hand,
A horizontal synchronization signal and a vertical synchronization signal are outputted from the control circuit 24, and drive the horizontal scanner 17 and the vertical scanner 16 via the horizontal and vertical drive circuits 23, respectively. In this way, a thermal two-dimensional image is formed within the liquid layer of the display element DE. The subsequent configuration operations within the broken line are as described above and will be omitted here for simplicity.

Note that when receiving TV radio waves, a receiver may be used instead of the video generation circuit 25. As another means for applying a thermal signal to the display element DE, for example, the first
An optical system 26 shown in Figure O is utilized. In the figure, a laser beam 28 output from a laser oscillator 27 passes through a thin film waveguide deflector 29 and then is reflected by a galvano mirror 30 while scanning the display element DE surface at high speed. By connecting an image signal circuit (not shown) to the laser oscillator 27, specific image formation becomes possible.

FIG. 11 is a schematic cross-sectional view showing an embodiment of a color display element according to the present invention, with the upper half being a transmissive display element and the lower half being a reflective display element, for convenience of explanation.

6 is a radiation absorbing layer, and 8 is a reflective layer, which is not provided in the transmissive display element DE shown in the upper half of the figure. 31
is a color mosaic filter, and its specific configuration and manufacturing technology have already been explained in detail in Japanese Patent Publications No. 52-13094 and Japanese Patent Publication No. 52-36019. Detailed explanations of these will be omitted here as they are incorporated. 2 is a liquid layer, 3 is a transparent protection plate, and except for the color mosaic filter 31, the elements constituting the display element DE are as explained in FIG. 2, and will be omitted here for simplicity.

In the illustrated example, the liquid layer 2 in contact with the red filter part (R) of the color mosaic filter 31 is heated by thermal conduction by the radiation absorbing layer 6 that has absorbed the radiation 6a, and a liquid layer heating part 13 is formed above this. Then, the collimated illumination light 4 that has been reflected by the reflective film 8 or transmitted through the radiation absorption layer 6 passes through the liquid layer heating section 13 and is heated as shown by the broken line by the mechanism described above. The light exits the display element DE through a bent optical path as shown by the two-dot chain line, which is different from the optical path of the light that would have passed if the liquid layer heating section 13 was not provided. When white light enters the red filter section (R), the transmitted light or reflected light that comes out of the display element DE is only light that makes red visible (hereinafter referred to as red light). Blue filter section (B) and green filter section (G)
The path of the light passing through the red filter section (R) is also the same as the path of the light passing through the red filter section (R). However, in this figure, only the light rays that do not pass through the liquid layer heating section 13 are shown for the green filter section (G). Furthermore, when the incident light 4 is white light, the light that has passed through the blue filter section CB) is only the light that makes blue visible (hereinafter referred to as blue light), and the light that has passed through the green filter section (G). The only light that can be seen is green (hereinafter referred to as green light). When viewing the display element DE in the direction of the light passing through the liquid layer heating section 13, an observer (not shown) sees pseudo-color by the additive coloring method.

For example, the liquid layer heating section 13 is formed by simultaneously heating the liquid layer 2 in the red filter section (R), the green filter section (G), and the blue filter section (B) of the adjacent color mosaic filters 31. At times, a viewer (not shown) can see white.

Furthermore, as explained in FIG. 2, by arranging a light-shielding grating (not shown) in front of the display element DE, some of the light emitted from the display element DE passes through the liquid layer heating section 13. By passing only the incoming light through an aperture of a light-shielding grating (not shown), a clearer pseudo-color display using the additive coloring method can be obtained.

FIG. 12 shows a simultaneous color light valve type projection device, which has three channels of red, blue, and green.
34 are arranged in parallel and projected onto the screen 12 at the same time, and the rasters of the three primary colors are neatly superimposed on the screen 12. As shown in FIG. 13, a white light source 14'' is separated into the three primary colors by two gicroic mirrors 35 and 36, and is used as a light source for illuminating red, blue, and green projection devices. Therefore, the luminous flux utilization rate of the light source is approximately three times that of the sequential type.

FIG. 14 is a schematic sectional view of another display element according to the present invention, FIG. 14(A) is a transmissive type, and FIG. 14(B)
1 and 2 respectively indicate reflective display elements.

In the figure, 3 indicates a transparent protection plate (which may not be used when display element DE is used horizontally), 2 indicates a liquid layer, and these have the same functions as those explained in Fig. 1. is an element. 4o is a thermally conductive insulating layer, and on both sides thereof, a plurality of heating resistance wires 41 and 42 as heating elements are two-dimensionally arranged in a matrix shape so as to intersect with each other sandwiching the insulating layer. be. 5 is a substrate serving as a support plate for these heat generating resistance wires 41 and 42 and the insulating layer 40. Figure 14 (
In the case of the transmissive display element DE shown in A), the heating resistance wires 41, 42, the substrate 5 and the insulating layer 4° are transparent; for example, the heating resistance wires 41, 42 are made of a transparent thin film of indium tin oxide. It consists of and,
In these display elements DE, a predetermined heating resistance wire 41
．． 42 are both selected and generate heat, the liquid layer heating part (
(not shown). Also, the second
As mentioned above in the figure, the pressure absorption film 9, the reflection lll8
is used as necessary.

Next, an example of matrix driving of such display elements will be described in more detail with reference to FIG.

In the figure, DE indicates a display element, which can be considered to have the same detailed configuration as explained in FIG. 14. This display element DE has X sL, X m , and X n .

The heat generating resistance wires of the nail shafts of X o and X p (these are called row lines) and the heat generating resistance wires of the blade shafts of Yc, Yd and Ya (
These are called column lines), and the column lines Yc, Y
One of d and Ye is connected to a common DC power supply, and the other is a transistor Tr, ~Tr3 whose emitter is grounded, respectively.
is connected to the collector side of the

Row lines X e , X m , X n , X o ,
When heating current pulses are sequentially applied to Xp, the liquid layers (not shown) corresponding to these row lines are sequentially heated in a linear manner. Since the temperature is set to be equal to or less than the threshold value, a liquid layer heating portion 13 in a high temperature region for heating display does not occur in the liquid layer. on the other hand,
Synchronizing with the application of the heating current signal, a video signal pulse is applied to the base side of the transistors Tr1 to Tr3 disposed at the emitters to turn on the transistors Tr and to Tr3.
For the 6-column lines Yc, Yd, and Ye connected to
Apply a predetermined video signal. By applying this video signal, the liquid layers corresponding to the column conductors Yc, Yd, and Ye are linearly heated. As a result, the intersection of the row line and the column line where the heating current pulse and the video signal are synchronized is heated additively by the heat generated by both lines, and the degree of heating of the liquid layer exceeds the threshold value for heating display. If the conditions are set so that the liquid layer heating section 13 is formed in the liquid layer corresponding only to the case where the liquid layer is heated additively, the liquid layer is heated at the intersection of the selected row line and column line. A section 13 is formed.

Note that in the above example, even when the driving method is changed as follows, images can be formed in exactly the same way. That is, even if a modification is made in which a video signal is applied to the row line and a heating current signal is applied to the first column line, the effect is exactly the same. In this way, the display element DE illustrated in FIG. 14 also enables matrix driving. When the thickness of the liquid layer of the display element DE is very thin, the following effects occur by installing the heating resistance wires arranged in stripes on both the transparent protection plate side and the substrate side as described above. .

■ The manufacturing process is simplified and the yield is improved.

■ Good thermal efficiency as the liquid layer is heated from both sides.

etc.

It is desirable to separately provide a heat sink to enhance the heat dissipation effect of the heat generating resistance wire. The substrate 5 (Fig. i314) can be used as a substitute for this heat sink. The above-mentioned row lines and column lines are separated by an insulating layer 40, and since the insulating layer 40 has several thicknesses, if both signals are applied at the same time due to the difference in heat conduction, liquid If the conductive heat does not reach layer 2 at the same time, the formation of the C1 liquid layer heating section may be inhibited.

Therefore, in order to further enhance the additive heating effect, it may be preferable to delay the applied pulse to the signal line closer to the liquid layer 2 than the signal pulse to the other signal lines. Note that it is not necessary that all of both signal lines be formed of heating resistors. Rather, in order to save energy, it is preferable to configure only the intersection of row lines and column lines with a heat-generating resistor, and configure the rest with a good conductor such as AM, but this would complicate the manufacturing process. There are drawbacks to being.

Further, another example of a heat generating element as a heat generating element for configuring a display element suitable for matrix driving as shown in FIG. 15 will be explained with reference to FIG. 16.

FIG. 16 is an external perspective view schematically depicting a partial area of the heating element. In the figure, reference numeral 45 denotes a heating resistor layer, which is obtained by forming a known heating resistor (for example, nichrome alloy, hafnium boride, tantalum nitride, etc.) into a planar film. Although not shown, this resistance layer 45 naturally extends downward in the drawing. Also, 46a, 46b, 46c
.

46d are column conducting wires, 47a and 47b.

47c are all row conductors. All of these conductive wires are made of good conductors such as gold, silver, copper, and aluminum (although not mentioned, the conductive wires are generally covered with an insulating film (not shown) such as 5i02). It is.

). In the illustrated heating element, for example, when the column conductor 46b and the row conductor 47c are selected and a voltage is applied to both, the resistance layer 45 corresponding to the intersection 48 of both is selected.
Electricity is applied to the – part of the unit, which generates heat.

In this way, it is possible to generate heat at any intersection of the row conductor and the column conductor.

Therefore, the heating element shown in FIG.
42 and the insulating layer 40, a display element incorporated in place of the heating element as a heating element can display a dot matrix image using the same matrix driving method as the example shown in Fig. 15. be.

By the way, on the heating element side shown in Fig. 16,
It is also possible to provide the heating resistance layer 45 in a divided manner only at the intersection of the row conductor 46 and the column conductor 47 (the conductors are insulated from each other in other areas), and such a configuration (FIG. 17) is possible.
In this case, it is possible to substantially prevent the occurrence of losstalk, which is inconvenient for image formation faithful to the signal.

In the example of FIG. 17, the row conductors 47a, 47b...
(hereinafter referred to as the row conductor 47) and column conductors 4ea, 46b.
- (hereinafter referred to as column conductor 46) is S i02 , S
Although they are arranged through an insulating film (not shown) such as i3 N4, the insulating film in the intersection area of the row conducting wire 47 and the column conducting wire 46 is removed, and instead, heating resistors 45b, 45b, .
... (hereinafter referred to as heating resistor 45) is embedded.

Next, in FIG. 18, such a heating element as shown in FIG. An example of driving an integrated display element using an IJ/NX will be described in more detail. 11@force selection circuit 10
3 is the material shaft drive circuit 101a, 101b... (hereinafter 1
The row axis drive circuit lot) is electrically coupled to the signal line number, and furthermore, the 11 axis drive circuit 1 of each
Each output terminal of 01 is coupled to a respective row conductor 47.

There are various ways to connect the output terminals and the row conducting wires 47, but in this specification we will explain the basic aspect. Suppose it is connected to a conductor.

Blade axis selection circuit 1041 column axis drive circuit 102a.

102b, ... (hereinafter referred to as the blade shaft drive circuit 102 and l,
The same applies to the relationship between the column conducting wires 46 and 46. The image control circuit 105 is electrically connected to the rod selection circuit 103 and the column selection circuit 104 by signal lines.

The image control circuit 105 outputs an image control signal to instruct the rod shaft selection circuit 103 to select which material shaft, and the same applies to the blade shaft selection circuit 104. That is, in response to an image control signal from the image control circuit 105, the rod shaft selection circuit 103 selects (switches on) a specific rod shaft (row conducting wire) via one of the rod shaft drive circuits 101. For example, when the rod shaft selection circuit 103 selects the row conductor Xp, it issues an XP row selection signal, and in response to this, the rod shaft drive circuit 102Xp inputs a row shaft drive signal even if ;kJ is applied to the row conductor XP. On the other hand, when a video signal, which is one of the image control signals from the image control circuit 105, is input to the blade axis selection circuit 104, in response to the command, the blade axis selection circuit 104 selects a predetermined blade axis (column conductor). Select 0 For example, if the blade axis selection circuit 104 selects the column conductor Ye, the blade axis drive circuit 10
2Ye receives the Ye column selection signal issued from the blade axis selection circuit 104 and switches the column conductor Ye.

Turn on (conducting).

If the selection of the material axis and the selection of the blade axis are made synchronously, in this example, the intersection point of the row conductor Xp and the column conductor Ye (selection point;
A current flows through the heating resistor located at eYe), Joule heat is generated, and a liquid layer heating portion is formed in the liquid layer (not shown). Leakage current flows also at the non-selected points, but since it is less than the current value for forming the liquid layer heating portion, no liquid layer heating portion is formed in the liquid layer. Also 1
By providing the heating resistor 45 with a diode function, the leakage current can be made even weaker.

In this way, in the same way as explained in FIG. 15, in FIG. 18, the row axis drive signal is used to perform line sequential scanning, and in synchronization with this, the blade axis selection signal is output, and the blade axis drive circuit A two-dimensional image display can be performed by bringing the selected column conductor 46 into a conductive state via the conductor 102 . Incidentally, the blade axis selection circuit 104 outputs a blade axis selection signal in response to a command by a video signal. At this time, the direction of the current flowing through the heating resistor does not matter. Such row and blade axis selection circuits 103, 104 and row and blade axis drive circuit 101.1
02 is constructed using a known technique using shift transistors, transistor arrays, etc.

In addition, in the matrix-driven display method using the heat generating elements described above, the transmissive display element DE shown in FIG. 14(A) can also be used as described above in FIG. A pressure absorbing membrane 9 can also be used, or the pressure absorbing membrane 9 shown in FIG.
), if necessary, corrosion-resistant silicon oxide is added between the liquid layer 2 and the reflective film 8 or between the liquid layer 2 and the heat generating element (for example, the heat generating resistance wire 41 therein). By interposing a film or a silicon nitride film, reaction corrosion between the liquid layer 2 and these can be appropriately prevented.

In addition, the red filter part (R), green filter part (G), and blue filter part (B) of the color mosaic filter shown in FIG. In the display element DE shown,
By arranging them at the intersection of the heating resistance wires 41 and 42 (or, in the case of the heating element shown in FIG. 17, on the heating resistor 45), similar to the example shown in FIG. Of course, by adopting this configuration, color display can be performed using the same principle as in FIG. 11 with a display element using the heating elements shown in FIGS. 14 and 17, respectively.

However, in a light valve type projection device as a display device using a display element using such a heating element, the portion related to the radiation input means as shown in FIG. 7 or FIG. , a laser light source and a light modulator (not shown),
Of course, a rotating polygon mirror, galvano mirror, lens, etc. are not necessary. Of course, it goes without saying that such a matrix-driven display element can also be applied to the light valve type projection device shown in FIGS. 3 to 6.

FIG. 19 is a schematic partial view of another modified example of a heating element as a heating element. The heating parts of the heating element 51 in FIG. 14 are arranged in a planar dot matrix, whereas the heating parts of the heating element 51 in this figure are arranged in a dotted line. It is something that Reference numeral 49 denotes one heating resistor, which is arranged alternately with the insulating layer 51b in the line a-a' direction. Electrodes 50a are provided on both sides of this heating resistor 48, respectively.

50b is provided. This electrode 50a side is commonly connected and grounded. The other electrode 50b side is
They are respectively connected to the electronic switches of the switching circuit 51a. The other end of this electronic switch is commonly connected to a DC power source (not shown).

It is assumed that each electronic switch of this switching circuit 51a is opened and closed according to an image signal.

Figure 20 shows a display device 41+ that uses the heating elements shown in Figure 19 to project a color image onto a screen.
It is an i-composition.

Reference numerals 57r, 57g, and 57b are a red light source, a green light source, and a blue light source that output red light, green light, and blue light, respectively, and emit light alternately in time series in this order.

561L and 56b are half mirrors, each with a green light source 57
g, the red light source 57 by reflecting the light from the blue light source 57b;
This is for directing the light in the same direction as the r light. 55
is a line image optical system composed of a cylindrical lens 54, etc., and is a reflective display element DE incorporating the heating element 51 shown in FIG. It is used to form an image of either the red light 'M 57 r , the green light source 57g, or the blue light source 57b.The line-shaped light image formed on the display element DE is If a liquid layer heating portion is not formed in the liquid layer of DE, the light is reflected by the display element DE, and all of the light is focused by the line image forming optical system 55 onto the light shielding filter 7c via the display element DE. 52 is a lens. , 53
Reference numeral 58 indicates a carpano mirror as an example of a light deflector, and 58 indicates a lens, by which light scattered from the liquid layer heating portion of the display element DE forms an image on the screen 12. Also,
The galvano mirror 53 is for scanning an image corresponding to the line image reflected from the display element DE in the direction of the arrow on the screen 12.

Assume that the galvanometer mirror 53 is now located at a certain position.

The red light from the red light source 57r is imaged into a line on the display element DE by the line image forming optical system 55. In synchronization with this, the heat generating resistor 49 of the heat generating element 51 of the display element DE generates heat by being energized via the switching circuit 51a in response to the video signal, causing the liquid layer of the display element DE to form a liquid layer heating section. (not shown) is formed. The red light scattered by this liquid layer heating section is transmitted through a lens 52 and a galvanometer mirror 5.
3. The image is formed as a point image on the screen 12 via the lens 58. Regarding the next green light source and blue light source, a line image consisting of a point image corresponding to the video signal is superimposed on the same line F on the screen 12 by the same operation as the red light source. In this way, the galvano mirrors 5 are displayed one after another on the screen 12.
If a line image is formed by scanning No. 3, a color projected image corresponding to the video signal will be formed on the screen 12.

In addition, in the embodiments from FIG. 14 to FIG. 20, when a liquid with good conductivity such as alcohol is used as the liquid of the liquid layer, as explained in FIG.
When using the heating element shown in Fig. 19 as a display element and not using a reflective film, it is necessary to
Needless to say, a thin insulating layer such as 02 may be interposed. In addition, when using a conductor reflective film as the reflective film,
Needless to say, a thin insulating layer such as 5i02 is interposed between the reflective film and the heating element.

FIG. 21 is a block diagram of a liquid circulation system of a display device for cooling a liquid layer of a display element. Display element DE
When driven continuously for a long time, the liquid layer 2 in the element DE
The temperature gradually rises due to heat accumulation, and vapor bubbles may suddenly occur in the liquid layer 2, which is a thin layer of liquid. If the amount of heat storage increases in this way, it will cause noise, which is not desirable.

Therefore, in this illustrated example, in order to prevent heat accumulation in the liquid layer 2,
The liquid in the co-liquid layer 2 is circulated between the display element DE, the vaporization chamber 63, and the liquefaction chamber 64.

The role of the vaporization chamber 63 is to remove such surplus heat as vaporization heat, and to absorb or relieve pressure caused by unexpected generation of vapor bubbles.

Further, a pressure reducing means 62 is added to the vaporization chamber 63 in order to maintain it in a predetermined reduced pressure state.

If the pressure in the vaporization chamber 63 is lower, the evaporation rate of the liquid will increase, so the rate of heat dissipation will be faster.6 The vaporized vapor then releases heat outside the system in the liquefaction chamber 64. The liquid is liquefied, passed through the circulation path 65, and then injected into the liquid layer 2 within the display element DE.

Therefore, while maintaining the reduced pressure state by the pressure reducing means 62, the liquid flows from the liquid layer 2 through the circulation path 65 to the vaporization chamber 63, from the vaporization chamber 63 to the liquefaction chamber 64, and then from the liquefaction chamber 64 to the liquid layer 2 again. The 4-distribution liquid circulation system firstly removes thermal noise as an image defect, and
Second, it is effective in removing noise caused by pressure.

Furthermore, by attaching a cooling means 61 consisting of a heat dissipation means or a Peltier effect element to the display element DE, the above-mentioned effect can be promoted, so that it is possible to project an enlarged screen onto the above-mentioned screen. can.

By the way, the liquid circulation system described in this figure does not require the intervention of a forced liquid circulation device such as a pump. In other words, a liquid circulation system can be constructed by natural convection of liquid.

In addition, when flowing the liquid of the liquid circulation system into the liquid layer 2 during the period of forming the liquid layer heating section, it goes without saying that the flow rate should be set to a level that does not disturb the liquid layer heating section.

Further, the pressure reducing means 62 can be constructed using a vacuum pump or a solenoid valve, and a fan may be provided on the outer wall of the liquefaction chamber 64 for the purpose of promoting heat radiation.

Further, if the time from when a heat pulse is applied to the liquid until a liquid layer heating portion (not shown) is formed in the liquid layer 2 is called a rise time, the rise time is about 10 p, sec. Conversely, the time during which this liquid layer heating section disappears or is erased is called the fall time, and the fall time I
The fastest speed is 30 gsec.

It is. The rise time and fall time are affected by the liquid temperature in the liquid layer 2, pulse application time, applied voltage, heat radiation conditions, etc., and are also affected by the specific heat and thermal conductivity of the liquid. It cannot be easily and generalized. However, from the viewpoint of afterimage effects, etc., the fall time is not required to be very fast. The desired fall time can be set by adjusting the composition of the liquid.

The smaller the specific heat of the liquid constituting the liquid layer 2, the easier it is to form a liquid layer heating section with lower power consumption, which is advantageous.

For example, methyl alcohol (boiling point 65℃, specific heat 0.599
cal/g・deg at 20°C), x chill alcohol (at 78°C, 0.58 ca!/g”
deg at 25°C, n-propyl alcohol (at 97°C, 0.58 El cal/go deg
at 25°C), isopropyl alcohol (at 25°C), isopropyl alcohol (at 25°C),
°C, same (1.5 flll cal/gadeg at
20°C), n-butyl alcohol (118°C, 0.
563 cal/go tJeg at 25℃)
, hexane (126°C1 0.505 cal/
g-deg at 25°C), benzene (at 80°C
, 0.25 cal/g・deg at 25°C), toluene (110°C 1 0, 269 cal/g
deg at 25°C), xylene (144 deg at 25°C, 0 deg at 25°C),
, 387 caI/go deg at 30'
0), carbon tetrachloride (77℃, 0.207 ca
l/g-deg at 20℃), ethylene glycol (198'O1 0.511119cal/g@
deg), glycerin (290°C, 0.569
If the liquid layer 2 is composed of a liquid (whether alone or in combination) such as water (boiling point io
o'c, specific heat 1 cal/g-deg) A much better display contrast can be obtained than in the case of the liquid layer 2 consisting of only one liquid layer 2. Therefore, suitable specific heat conditions are: temperature 20-25'C; 0.7 cal/g*d
eg or less. For the same liquid, the higher the temperature of the liquid layer heating section is compared to the surrounding area, the higher the display contrast becomes.

However, methyl alcohol, ethyl alcohol,
With a low boiling point solvent such as carbon tetrachloride, the temperature cannot be raised too high because vapor bubbles will occur if the temperature is raised. This is the reason why display contrast cannot be increased. On the other hand, liquids with a single high point, such as ethylene glycol and glycerin, do not produce vapor bubbles even if they are heated and the temperature is raised, so the temperature gradient of the heated liquid can be widened and the display contrast can be increased. It is possible to do so. In experiments, good display contrast was obtained for liquids with a boiling point of 80°C or higher. For example, isopropyl alcohol is one suitable example.

In addition to this, the present invention can also display colors by dissolving dyes in the above-mentioned type of liquid of the liquid layer used in the display element and using the liquid layer that exhibits various colors. For example, dyes used in magenta-colored liquids include C, 1, Direct Red 3, Direct Red 16, Direct Red 20, Direct Red 44, and Direct Red 54. Same 55
, 75, 77, 81, 83, 101, 11
0, 152, C, I, acid red 1. Same 3
．． Same 5, Same 8, Same 12, Same 17, Same 19, Same 22, Same 3
1, 32. 37, 41, 47, 5B, 80
, 71. Same 112. Same 115゜ Same 154, Same 155,
Same 160, Same 171, Same 187, C, 1, Asian Red Violet 5, Same 7, Same 11. There are C,1, Direct Violet 6, Direct Violet 7, Direct Violet 16, etc. C, 1, direct dye is used as a dye that uses a liquid that produces a yellow color.
Yellow 18, Acid Yellow 22, Acid Yellow 27, C, 1, Acid Yellow 1, Acid Yellow 13, Acid Yellow 18, Acid Yellow 106, Acid Yellow 186, etc. The dye used for cyan coloring liquid is C,1
, Direct Blue 1, Direct Blue 1, Direct Blue 37, Direct Blue 127, Direct Blue 149, Direct Blue 215, Direct Blue 231, C, I, and Acid Blue 15.

However, even if the liquid constituting the liquid layer is colored by appropriately selecting a dye as described above, the principle of image formation of the display element as described above in FIG. 1 remains the same. Therefore, when the liquid layer is colored, a single color image can be displayed.

In addition, when the liquid layer heating part is formed in the liquid layer (if you bring your viewing eye close to the display element, you can see the light passing through both parts at the same time as it enters your viewing eye). Since the non-heated portion of the layer is more strongly colored than the heated portion of the liquid layer, an image can be displayed depending on the degree of coloration.

Therefore, for a display element using such a dye in the liquid layer, the image of the display element may be projected onto a screen using a light valve type projection device as described above, but it is also possible to project an image of the display element onto a screen using an imaging optical system. The image can be displayed by directly projecting the image onto a screen.

As detailed above, the main effects of the present invention are as follows.

(ILIIff Since it is possible to arrange one small liquid layer heating section in high density as a unit of display pixel, high resolution image display is possible.

(2) By adjusting the duration of time in the liquid layer of the liquid layer heating section as one display pixel, still images or moving images including slow motion can be easily displayed.

(3) By employing a liquid circulation system in the zero display element, it is possible to present a noise-free and high-quality screen.

(4) Multi-color display and full-color display can be easily implemented.

(5) Since the structure of the device is relatively simple, its productivity is excellent, and the device has high durability and reliability.

(6) Can be adapted to a wide range of drive systems.

m, fh Since the display is performed by heating the liquid layer to a temperature below the boiling point instead of forming bubbles, less power is required for the display element, and the power supply unit, that is, the display element and display device, can be made smaller. can be converted into

(s),,4 In devices that perform light modulation and display using bubbles, there is a risk that the display device may be damaged due to cavitation when vapor bubbles disappear, but in the present invention, the liquid layer is simply heated to a level that does not boil. Therefore, the durability of the element is extremely high.

(9) When displaying with vapor bubbles, the liquid in the liquid layer is removed, which causes an increase in pressure, and a special liquid discharge location must be provided for this purpose, but in the case of the present invention, the increase in pressure is caused by the liquid layer. Because it is only the thermal expansion of the liquid, it hardly causes an increase in pressure, so there is no need to take pressure measures, or even if measures are taken, the display element itself can be miniaturized with only a pressure absorbing film. Moreover, it is durable even after repeated use with little influence of pressure.

(10) Since the contrast of the display depends on the degree of heating of the liquid in the liquid layer, it is easy to display halftones in an analog manner.

FIG. 1(A) is a schematic cross-sectional view for explaining the image forming principle of a transmissive display element according to the present invention, and FIG. FIG. 2 is a schematic cross-sectional view of a specific display element according to the present invention, and FIGS. 3 to 8 are schematic cross-sectional views for explaining the image M principle. 9 is a block diagram of a display device as an application example of the present invention; FIG. 10 is an external perspective view of an example of an input system for imaging signals using radiation;
Figure 1 is a schematic sectional view for explaining an example of the configuration of a color display according to the present invention, Figure 12 is a schematic configuration diagram of a color display device as an example of the application of the present invention, and Figure 13 is a color illumination optical system. A schematic configuration diagram of the system, FIG. 14 is a schematic cross-sectional view for explaining a configuration example of a matrix-driven display element according to the present invention, and FIG. 15 is a schematic illustration of an example of an image forming method according to the present invention. 16 and 17 illustrate each configuration example of the heating element.

[Brief explanation of drawings]

FIG. 1(A) is a schematic cross-sectional view for explaining the image forming principle of a transmissive display element according to the present invention, and FIG. FIG. 2 is a schematic cross-sectional view of a specific display element according to the present invention, and FIGS. 3 to 8 are schematic cross-sectional views of a display device as an application example of the present invention. 9 is a block diagram of a display device as an application example of the present invention; FIG. 10 is an external perspective view of an example of an input system for imaging signals using radiation; and FIG.
The figure is a schematic sectional view for explaining an example of the configuration of a color display according to the present invention, FIG. 12 is a diagram showing the basic configuration of a color display device as an application example of the present invention, and FIG. 13 is a diagram of a color illumination optical system. A schematic configuration diagram, FIG. 14 is a schematic sectional view for explaining a configuration example of a matrix-driven display element according to the present invention, and FIG. 16 and 17 are external perspective views for explaining each configuration example of a heating element, FIG. 18 is a block diagram of a matrix drive display device according to the present invention, and FIG. 19 is a dot-line heating element. Schematic partial drawing of etc., No. 20
1 is a schematic configuration diagram of a display device as an application example of the present invention, and FIG. 21 is a schematic diagram of a liquid circulation system used in the display element of the present invention. l: Heat generating element 2: Liquid layer 3: Transparent protection plate 4: Illumination light 5: Substrate 6: Radiation absorption layer 6a: Radiation 7: Grating 7a: First grating 7b = Second grating 7c, 7d:
Light shielding 74 ruta 8: Reflective film 9: Pressure absorption film
10: Heat generating layer 11: Schlieren lens 11':
Imaging lens 11a: Lens 11b: Condensing lens 12 Niscreen 13: Liquid layer heating section 1
4: Incident light 14': Light source 15: Cold filter 16 Two vertical scanners 17: Horizontal scanner 18: Mirror 18: Mirror 20
: Light modulator 21: Laser light source 22: Image amplification circuit 55: Line image forming optical system 57r: Red light source 57
g: Green light source 57b: Blue light source 61: Cooling means 62: Decompression means 63: Vaporization chamber
64: Liquefaction chamber 65: Circulation path 101:
Needle axis drive circuit 102: Column axis drive circuit 103: Needle axis selection circuit 104: Column axis selection circuit 105: Image control circuit DE: Display element (A) (B) Figure 1 Figure 2 Figure 4 Flash Figure 5 10 Sen No. 14 Close No. 15 Continuation of page 1 0 Inventor Masayuki Usui 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Co., Ltd. 0 Inventor Atsushi Someya No. 2, 3-30iJ, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Co., Ltd. Internal Proceedings Rectification (Method) March 1980, Japan Patent Office Commissioner 1. Indication of Case 1982 Patent Application No. 182891 2. Title of Invention Image Display Method 3. Person Making Amendment Relationship with pain Patent Applicant (l OO) Canon Co., Ltd. 4th Representative Person 5. Date of amendment order 1. Date of dispatch: February 22, 1981 6. Subject of amendment "1 Brief explanation of Δ plane ” column. 7. Delete lines 3 to 20 on page 60 of the specification of contents of the amendment.

Claims (1)

[Claims] The refractive index of the liquid in the heated region is changed by heating a liquid layer made of a liquid that is transparent to visible light to an extent that boiling does not occur in the liquid layer according to image information. An image display method characterized in that the image is developed by changing the optical path of light passing through the area.