JPS6261245B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a novel display device.

Currently, cathode ray tubes (so-called
CRT) are widely used. However, this
Regarding CRTs, there are still complaints that they do not reach the same level as hard copies using silver salt or electrophotography in terms of image quality, resolution, and display capacity. In addition, as an alternative to CRT, attempts have been made to commercialize so-called liquid crystal panels that display dot matrix using liquid crystals, but these liquid crystal panels also have problems in terms of drive performance, reliability, and productivity. I haven't gotten anything that satisfies me.

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

That is, an object of the present invention is to provide a novel display device that displays high-resolution, high-quality images, has excellent drive performance, productivity, and reliability, and has high-density pixels.

Hereinafter, the present invention will be specifically explained in detail with reference to illustrated examples.

One of the principles of image formation in the present invention will be outlined with reference to FIGS. 1 to 8.

In the figure, 1 is a radiation absorption layer, 2 is a thin liquid layer,
3 indicates a transparent protection plate, and by laminating these plates, the display element shown in FIG. 1 (schematic cross-sectional view) is constructed. At this time, the radiation absorption layer 1 is a colored (preferably black) film that efficiently absorbs radiation, especially infrared rays, and is made of various inorganic or organic materials that are difficult to melt by themselves. can get. If the absorbing layer 1 itself lacks a supporting function, it is desirable to add a radiation-transmitting support plate made of glass or plastic (not shown).

The liquid constituting the thin liquid layer 2 can be roughly classified optically into a translucent liquid, a colored liquid, and a cloudy liquid. The basic composition of this liquid is water or various organic solvents used alone or in combination.

Specifically, the organic solvents include those having 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol. Alkyl alcohols; amides such as dimethylformamide and dimethylacetamide;
Amines such as triethanolamine and diethanolamine; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol , hexylene glycol, diethylene glycol, and other alkylene glycols in which the alkylene group has 2 to 6 carbon atoms; glycerin; polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol methyl or ethyl ether, triethylene glycol monomethyl (or ethyl) ether, etc. and lower alkyl ethers.

In addition, the above-mentioned colored liquid refers to a colored liquid (including black) obtained by dissolving or dispersing various dyes and pigments in the above-mentioned liquid, and the cloudy liquid refers to
A white or light-colored liquid obtained by dispersing light-diffusing fine particles (regardless of whether they are solid) in the above-mentioned liquid. The thickness of the thin liquid layer 2 described above is such that the amount of transmitted light is approximately half or less of the amount of incident light (generally,
1 μm to 100 μm) is desirable. Furthermore, at this time,
It is not necessary that the amount of transmitted light be reduced over all wavelengths in the visible range. In other words, it may be a reduction in part of wavelength light in the visible range. Further, this decrease in the amount of transmitted light may be caused by either absorption or scattering of light.

By the way, it is necessary to avoid liquid having the same color as the absorbing layer 1. This is because the contrast between the image area and the non-image area may not be maintained, as will become clear from the image forming principle described later.

As the transparent protection plate 3, a light-transmitting (colorless to light-colored) glass or plastic with as much pressure resistance as possible is used. Note that this protection plate 3 may not be used when the display element is arranged horizontally.

When the display element of FIG. 1 configured as described above is irradiated with radiation (particularly infrared rays) 5 from the right side of the drawing, corresponding points on the absorption layer 1 generate heat. When a part of the absorbent layer 1 generates heat in this way, the liquid in contact with it is heated by thermal conduction, the temperature of the liquid rises, and eventually it boils, forming vapor bubbles 4 in the thin liquid layer 2. be done. In addition, when irradiating the display element with the radiation 5, it can be irradiated in a pattern corresponding to a predetermined image, or a laser light source can be used to irradiate the radiation 5 with a large number of beams. Although the light is irradiated all at once in the form of a dot, it is also possible to use a method in which the absorption layer 1 is scanned with one beam or one line beam. However, since it is actually extremely difficult to form vapor bubbles 4 with uniform optical properties over a wide area, the latter method, that is,
The method of forming the vapor bubbles 4 in a dot shape can be said to be an advantageous method from a practical point of view.

Further, the direction in which the radiation 5 is irradiated is not limited to the illustrated example. That is, when the transparent protection plate 3 and the liquid thin layer 2 transmit radiation, it is also possible to irradiate the radiation from the left side of the drawing.

In the present invention, the form of the vapor bubbles 4 formed in the thin liquid layer 2 by the application of a heat pulse as described above is such that they are generated from the surface of the absorbing layer 1 and do not separate therefrom. The growth increased and reached the level of protection plate 3.
A flat shape that creates a liquid void in the thin liquid layer 2 that reaches it is effective.

In the present invention, when vapor bubbles 4 are formed in the liquid thin layer 2, the first aspect (when using a translucent liquid)
In this case, display pixels can be identified based on the difference in the amount of light reaching the viewing eye 6. In other words, the light reflection on the surface of bubbles in a translucent liquid is originally small, but if the bubbles are minute, the effects of diffraction and bubble curvature appear, and the light scattering effect of the bubbles is reduced. Become big. On the other hand, in a region without bubbles, most of the observation light 7 reaches the observation eye 6 after being reflected or absorbed by some elements of the display element, resulting in the above-mentioned difference in light amount. Incidentally, at this time, the ideal shape of the bubble is a hemispherical one (it does not matter whether the bubble touches the protective plate or not), and its size is approximately 40 μm in diameter. is preferred.

In the second mode (when colored liquid is used), the area where the bubbles are formed is colored by the absorption layer 1, and the other areas are colored by the liquid. Display pixels can be identified.

In the third mode (when a cloudy white liquid is used), the display pixels are identified by the appearance of colored parts (places where bubbles are formed) on a white or light-colored background.

In the above embodiment, the time required for the bubbles 4 to disappear is usually 30 msec, and it is desirable that it be as long as possible in order to utilize the afterimage effect.

In addition, the method for forming the vapor bubbles 4 that will become display pixels by radiation heating has been described above.
In the present invention, it is also possible to replace the absorbing layer 1 in FIG. 1 with a heat transfer layer made of a metal (not shown), and to bring a heat generating element (not shown) close to or in contact with this to heat the liquid by conduction. be. However, in this case,
Unless specific measures are taken to regulate the direction of heat transfer, the disadvantage is that display pixels are not clearly defined due to heat diffusion.

Note that the display element configuration for implementing the first aspect described above is as shown in FIG. 7 or 8.
Interface or protective plate 3 of absorbent layer 1 in contact with liquid thin layer 2
It is preferable to make the interface a diffusion surface DP, since this can enhance the discrimination effect of display pixels.
Further, at this time, the closer the refractive indexes of the material of the protection plate 3 and the liquid are, the more distinguishable the display pixels will be.

In the present invention, in order to further enhance the discrimination effect of display pixels, a white or light-colored, light-reflecting or light-diffusing optical film 8 is provided between the radiation absorption layer 1 and the liquid thin layer 2.
It is also possible to intervene separately. (FIG. 2) Such optical 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.

Furthermore, in the present invention, as shown in FIG. 1, in the case where the vapor bubbles 4 generated in the thin liquid layer 2 do not reach from the absorbent layer 1 to the protective plate 3 (FIG. 3), However, for example, when a brightness difference, a saturation difference, or a hue difference appears, a certain effect of identifying display pixels can be obtained. Furthermore, if this is actively utilized, it becomes possible to display halftones.

In the present invention, when the vapor bubbles 4 are generated in the thin liquid layer 2, there is a sudden increase in pressure, so if the thin liquid layer 2 is constructed in a closed system, there is a risk of damage to the display element. strong. Therefore, this liquid thin layer 2
It is desirable to connect both to an air chamber or an acumulator (not shown) to alleviate the increase in pressure in the thin layer 2. Alternatively, as shown in FIG. 4, a pressure absorbing film 9 may be interposed within the display element to absorb the pressure generated in the thin layer 2.

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.

Further, as a modification of the present invention, the thin liquid layer 2 may be connected to a heating chamber (not shown) and the liquid may be circulated and heated in advance to a temperature close to its boiling point. At this time, since the amount of heating and the heating time required to form the vapor bubbles 4 can be reduced, it is possible to greatly accelerate the formation speed of the vapor bubbles 4, that is, the display pixels.

For the same purpose, a heating element layer 10 is installed between the radiation absorbing layer 1 and the liquid thin layer 2 (FIG. 5) or between the radiation absorbing layer 1 and the optical film 8 (FIG. 6) of the display element.
may be provided, thereby uniformly preheating the liquid thin layer 2 and raising the temperature to near the boiling point of the liquid.

At this time, if the absorption layer 1 or the optical film 8 is a conductor, it is desirable to provide an insulating layer (not shown) between them and the heat generating layer 10.

In the present invention, the heat generating layer 10 (FIGS. 5 and 6
As shown in Fig. 2), the heating element is not necessarily limited to a planar heating element that covers the entire display surface. In other words, this may be a linear heating element or a lattice heating element (none of which is shown) that corresponds to the scanning line of the radiation beam.

At this time, if the radiation irradiation and the heating by the heating element are synchronized, further energy saving effects can be obtained.

Materials for such heating elements include HfB ₂ and Si ₃ N _4.
Examples include metal compounds typified by, etc., and alloys such as nichrome.

Furthermore, in the present invention, a display element configuration in which a corrosive component comes into direct contact with the liquid thin layer 2 should be avoided, since this will shorten the life of the element. In other words, in a configuration in which a corrosive component is in contact with the thin liquid layer 2, chemical corrosion, electrochemical corrosion, mechanical corrosion due to cavitation, etc. occur, and the element is often damaged. Therefore, in such cases, it is desirable to form a corrosion-resistant protective film (not shown) at the interface between the thin liquid layer 2 and the corrosive component. The material for this protective film is a dielectric metal oxide (SiO ₂ , TiO ₂ , etc.)
and heat-resistant plastics.
In the present invention, of course, the optical film 8 may also serve as this protective film depending on its function.

Next, as an application example, the principle of forming a color image will be explained with reference to FIG.

FIG. 9 is a schematic cross-sectional view of a color display element. In the figure, except for the color mosaic filter 11 and the reflective layer 12, the other components are the same as those explained in FIGS. 1 to 8. elements can be used.

The specific structure of the color mosaic filter 11 and its manufacturing technology have already been disclosed in
Since it is explained in detail in Japanese Patent Publication No. 13094 and Japanese Patent Publication No. 52-36019, the detailed explanation will be omitted here by referring to these documents.

In the illustrated example, when vapor bubbles 4 are formed in the thin liquid layer 2 in contact with the red filter portion R, the color is red due to the reflected light passing through this filter. or,
When vapor bubbles (not shown) are formed in the liquid thin layer 2 in contact with the green filter section G, a green coloration is observed due to the reflected light passing through this filter. Similarly, when vapor bubbles 4 are formed in contact with the blue filter section B, a blue coloration is observed due to the reflected light passing through this filter.

In this way, on the actual screen, the observer 6
The method visualizes pseudocolor using the additive coloring method. For example, when vapor bubbles are formed in adjacent R, G, and B at the same time, the observer 6 will see white.

Instead of each of the filter parts R, G, and B, an opaque colored layer (not shown) can be directly formed using a colored organic or inorganic pigment, but in either case. It is desirable to use a material that has good thermal conductivity and excellent heat resistance and impact resistance. Incidentally, in the case where coloring is caused by surface reflection of the pigment layer as in the latter embodiment, the reflective layer 12 is not necessary.

Such a reflective layer 12 is obtained by a metal thin film processed into a mirror surface.

Here, a schematic structural example of another display element according to the present invention will be shown using FIG. 10.

In the figure, numeral 3 indicates a transparent protection plate, and numeral 2 indicates a thin liquid layer, which are elements having the same functions as those explained in FIG. 1. 13 is a thermally conductive insulating layer, and a plurality of heating resistance wires 14, 15 are provided on both sides of the layer.
are arranged two-dimensionally so as to intersect each other with an insulating layer in between. 16 are these heating resistance wires 14,
15 and a support for the insulating layer 13. In this element, vapor bubbles 4 are formed in the thin liquid layer 2 in the area where they intersect only when the predetermined heating resistance wires 14 and 15 are both selected and generate heat.
It's designed.

Next, an example of driving such a display element in a matrix will be explained in more detail using FIG.

In the figure, reference numeral 17 indicates a display element, which can be considered to have the same detailed configuration as explained in FIG. 10. Now, if a heating current pulse is sequentially applied to the heating resistance lines Xl, Xm, A thin layer of liquid (not shown) corresponding to the line is sequentially heated linearly, but at this time, the degree of heating is set to be below the boiling point of the liquid, so vapor bubbles are generated in the thin layer of liquid. does not occur. On the other hand, heating resistance wires are arranged vertically in the drawing while synchronizing with the application of heating current pulses.
For Yc, Yd, Ye (these are called column lines),
Apply a predetermined video signal.

By applying this video signal, the resistance line Yc,
The thin liquid layers corresponding to Yd and Ye are heated linearly, but in this case as well, the degree of heating must be kept below the boiling point of the liquid, so this alone will not cause vapor bubbles in the corresponding thin liquid layers. Don't let it happen. but,
At the intersection of the row line and the column line where the heating current pulse and the video signal pulse are synchronized, the heating current pulse and the video signal pulse are mutually heated by the heat generated by both lines. If conditions are set so that the corresponding liquid thin layer foams only when heated in a compatible manner, vapor bubbles 18 are formed at the selected row/column intersection.

In the above example, even if the driving method is changed as follows, images can be formed in exactly the same way.
That is, even if the device is modified so that a video signal is applied to the row lines and a heating current pulse is applied to the column lines, the effect is exactly the same.

As mentioned above, the display element illustrated in FIG. 10 is also capable of matrix driving. In the case of the matrix drive method, it goes without saying that a radiation absorption layer is not required as an element component, but instead, a heat sink may be provided separately to enhance the heat dissipation effect of the resistance wire. desirable. A support 16 (shown in FIG. 10 can be used instead) for this heat sink. The row lines and column lines are separated by an insulating layer 13, and the thickness of the insulating layer 13 is several μm. If both signals are applied at the same time due to a time difference in heat conduction, foaming may be inhibited because the conducted heat will not reach the liquid thin layer 2 at the same time.Therefore, the mutual heating effect will be further enhanced. Therefore, it may be preferable to delay the applied pulse to the signal line closer to the liquid thin layer 2 than the signal pulse to the other signal lines.
It is not necessary that all of both signal lines be formed by heating resistors. Rather, in order to save energy, it is preferable to configure only the intersection of row lines and column lines with heating resistors, and to configure the rest with a good conductor such as Al, but this will reduce the manufacturing process. The disadvantage is that it becomes complicated.

Further, another example of a heating element for configuring a display element suitable for matrix driving as shown in FIG. 11 will be explained with reference to FIG. 12.

FIG. 12 is an external perspective view schematically depicting a partial area of the heating element. In the figure, 21 indicates a heat generating resistor layer, which is a known heat generating resistor (for example,
It is obtained by forming a planar film of nichrome alloy, HfB ₂ , Si ₃ N _4, etc.). Although not shown, this resistance layer 2
1 also extends downward in the drawing. Also, 2
2-1, 22-2, 22-3, 22-4 are all column conductors, and 23-1, 23-2, 23-
3, 23-4, and 23-5 are all row conductors.
All of these conductive wires are made of good conductors such as gold, copper, and aluminum. In the illustrated heating element, for example, the column conductor 22-2 and the row conductor 23
-3 is selected and a voltage is applied to both, the resistance layer 2 corresponding to the intersection 24 of both
1 is energized and generates heat.

In this manner, by arbitrarily selecting and energizing the row conducting wires and column conducting wires, it is possible to generate heat at any (row/column) intersection.

Therefore, in a display element as shown in FIG. 10 incorporating the heating element shown in the drawing, it is possible to display a dot matrix image using the same matrix driving method as in the example shown in FIG.

By the way, in the heating element shown in FIG.
It is also possible to provide the heating resistor layer 21 divided only at the intersection of the row conductor and the column conductor (conductors are insulated from each other in other areas), and in such a configuration (not shown), , it is possible to substantially prevent the occurrence of crosstalk, which is inconvenient for image formation faithful to the signal. Further, by arranging a heating resistor having diode characteristics at the intersection of the row conductor and the column conductor, it is possible to completely prevent crosstalk.

It should be noted that color display can also be performed in the matrix-driven display system using the heating elements described above by adopting the same configuration as the example shown in FIG. 9. Although not shown in the drawings, if the entire display element is made translucent, a so-called transmissive display element can be obtained. However, whether the display element is a transmissive type or a reflective type only causes a difference in the observation direction, and does not make a difference in the image forming principle itself based on the present invention.

Here, another application example of the present invention will be explained using FIGS. 13 and 14. FIG. 13 is a schematic configuration diagram of the display device, and FIG. 14 is a schematic external perspective view illustrating its optical system.

In the figure, when the display element 31 is continuously driven for a long time, the temperature of the thin liquid layer 32 inside the element 31 gradually rises due to heat accumulation (because the liquid is a thin layer). Steam bubbles may suddenly form inside. If the amount of heat storage increases in this way, it will cause noise, which is not desirable. Therefore, in the illustrated example, the liquid in the thin liquid layer 32 is circulated between the display element 31, the vaporization chamber 33, and the liquefaction chamber 34 in order to prevent heat accumulation in the thin liquid layer 32.

The role of the vaporization chamber 33 is to remove such surplus heat as vaporization heat, and to absorb or relieve the pressure caused by the generation of vapor bubbles due to the signal. Moreover, in the vaporization chamber 33,
A pressure reducing means 35 is added to maintain this in a predetermined reduced pressure state. By this pressure reducing means 35,
By keeping the inside of the liquid thin layer 32 in a low pressure state, vapor bubbles are formed at a lower temperature, so that driving energy can be reduced. Furthermore, since the evaporation rate of the liquid increases, the rate of heat dissipation is also accelerated, which is another effect of the pressure reduction means. The vaporized steam is then liquefied by releasing heat outside the system in the liquefaction chamber 34, and passes through the circulation path 36.
The liquid is injected into the liquid thin layer 32 within the display element 31 again. Therefore, while maintaining a reduced pressure state by the pressure reduction means 35, the liquid thin layer 32 passes through the circulation path 36 to the vaporization chamber 33, and from this vaporization chamber 33 to the liquefaction chamber 3.
4 and then from the liquefaction chamber 34 back to the liquid layer 32.
Removal of thermal noise as an image defect, and
Second, it is effective in removing noise caused by pressure.

Furthermore, by attaching a cooling means 37 consisting of a heat dissipating means or a Peltier effect element to the display element 31, the above-mentioned effects can be enhanced.

In order to apply a thermal signal to the display element 31, for example, an optical system 38 shown in FIG. 14 is used. In the figure, a laser beam 41 output from a laser oscillator 40 passes through a thin film waveguide deflector 42 and then is reflected by a galvano mirror 43 while scanning the surface of a display element 31 at high speed.
By connecting an image signal circuit (not shown) to the laser oscillator 40, specific image formation becomes possible. In reality, the display element 31 is intermittently irradiated with a laser beam having a spot diameter of approximately several tens of micrometers. and display element 31
The actual image forming mechanism in this case has been explained in detail above, so its explanation will be omitted here.

In this way, while forming an image on the display element 31 or after completing the image forming, the illumination light source 44
When the observation light 45a is irradiated toward the display element 31, the reflected light 45b is reflected by the magnifying projection lens system 46.
The enlarged screen is projected onto a screen (not shown) through the windows a and 46b. (13th
By the way, the liquid circulation system explained in FIG. 13 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.

Note that even when adopting the liquid quasi-ring system as described above, it is necessary to allow the liquid to flow at least during the period when vapor bubbles (display pixels) are formed in the liquid thin layer, as this will cause image disturbance. should be avoided.

In other words, the timing and speed of circulating the liquid are
It is desirable to synchronize to the display period of one frame.

Further, the pressure reducing means 35 can be constructed using a vacuum pump or a solenoid valve, and it is desirable to provide fins on the outer wall of the liquefaction chamber 34 for the purpose of promoting heat radiation.

The size of the vapor bubbles assumed in the present invention described above is approximately 10 μm to 100 μm in diameter, with particular focus on resolution. However, it is of course possible to implement the method outside the above range as long as resolution is not an issue.

Furthermore, if the time from the application of a heat pulse to the liquid until the formation of vapor bubbles is called the rise time, the rise time is about 10 μsec. On the other hand, if we call the time during which these vapor bubbles disappear or disappear, the fall time, the fall time is as fast as 30 μsec. The rise time and fall time are influenced by the liquid temperature in the thin liquid layer, liquid pressure, pulse application time, heat radiation conditions, etc., and are also easily affected by the viscosity and surface tension of the liquid. I can't argue with that. However, from the viewpoint of afterimage effects, etc., the fall time is not required to be very fast. A desired fall time can be easily set by adjusting the composition of the liquid. Generally, the liquid used in the present invention is made from various solvents, dyes, pigments, etc. Dyes include direct dyes, acid dyes, organic solvent dyes, etc. Solvents include water, alcohol, glycol, ketone, ester, and hydrocarbon dyes, especially ethyl alcohol, methyl alcohol,
Isopropyl alcohol, ethylene glycol,
Ethyl cellosolve, diethyl glycol, freon, and mixtures thereof are suitable. Low boiling point solvents are advantageous in terms of power consumption because bubbles are generated at low temperatures. If the bubbles are to remain as long as possible, especially if the display pixels are to remain, it is desirable to use a material that does not easily cool down and has a moderately high viscosity.
In addition, especially when it is desired to variably adjust the bubble duration, it is effective to use the above-mentioned pressure reduction means. In other words, the lower the liquid pressure, the lower the temperature at which vapor bubbles are formed. Therefore, the lower the pressure within the liquid layer is made by the variable pressure reducing means, the longer the display will last. Particularly when displaying still images or slow-motion moving images, the method of reducing the pressure of the liquid is effective.

As explained in detail above, the main effects of the present invention are as follows: 1. Since it is possible to arrange each minute vapor bubble in a high-density arrangement as a display pixel unit, a high-resolution image can be displayed. .

2. Still images or moving images including slow motion can be easily displayed by adjusting the duration of vapor bubbles serving as display pixels in the liquid layer.

3. By employing a liquid circulation system in the display element, a noise-free and high-quality screen can be presented.

4. Multicolor display and full color display can be easily implemented.

5 The structure of the display element is relatively simple, so
It has excellent productivity, and the element has high durability and reliability.

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

There are many things that can be mentioned.

[Brief explanation of the drawing]

1 to 10 are schematic cross-sectional views illustrating an example of the structure of a display element used in the present invention, and FIG.
Fig. 1 is a schematic explanatory diagram of an example of an image forming method according to the present invention, Fig. 12 is an external perspective view for explaining an example of the configuration of a heat generating element, and Fig. 13 is an example of an application of the present invention. FIG. 14 is a schematic configuration diagram of the display device, and is an external perspective view of an example of an input system for image forming signals. In the figure, 1 is a radiation absorption layer, 2 and 32 are liquid thin layers, 3 is a protection plate, 4 and 18 are vapor bubbles, 5 is radiation, 7 and 45a are observation lights, 8 is an optical film, and 9 10 is a pressure absorbing film, 10 is a heating element layer, 11 is a color mosaic filter, 12 is a reflective layer, 13 is an insulating layer, 1
４，１５，Xl，Xm，Xn，Xo，Xp，Yc，Yd，
Ye is a heating resistance wire, 16 is a support, 17 and 31 are display elements, 21 is a heating resistance layer, 22-1, 22-
2, 22-3, 22-4, 23-1, 23-2,
23-3, 23-4, 23-5 are conductive wires, 33 is a vaporization chamber, 34 is a liquefaction chamber, 35 is a pressure reduction means, 36 is a liquid circulation path, 37 is a heat radiation and cooling means, 38 is an optical system, and 41 is a laser It is a beam.

Claims (1)

[Scope of Claims] 1. A display element that basically has a liquid layer and a heat generating element that generates bubbles in the liquid layer so that light can pass through the liquid layer, and an image display element for this display element. A display device comprising a signal input means for inputting a signal corresponding to information to the heat generating element. 2. The display device according to claim 1, further comprising an illumination optical system for illuminating the element. 3. A display element that basically has a liquid layer and a heat generating element that generates bubbles in the liquid layer so that light passes through the liquid layer, a liquid circulation path that communicates with the liquid layer of the element, and the element. A display device comprising signal input means for inputting a signal corresponding to image information to the heat generating element. 4. The display device according to claim 3, wherein the liquid circulation path is provided with means for vaporizing and liquefying the liquid. 5. The display device according to claim 3, wherein a pressure reducing means is provided in the liquid circulation path. 6. The display device according to claim 3, further comprising an illumination optical system for illuminating the element.