JPH11305186A - Picture display board and picture display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain excellent picture display characteristics and to display a clear color image of high quality in a picture display board having image information display state holding function. SOLUTION: When writing light is radiated from a direction Y1 opposite to a direct viewing direction X1 on the picture display board 20, a part on an image recording layer 24 irradiated with the writing light is heated, phase transition occurs and an image is formed on the part. When a DC voltage is applied, transparent electrode layers 23, 25 heat the layer 24, so that phase transition is promoted. A visible light absorbing layer 27 absorbs visible light made incident from the direction X1. Since the image recording part has brightness different from that of other parts, the image can easily be recognized by direct viewing from the direction X1. An RGB filter is used as a color filter layer 22 and a red filter part R1, a green filter part G1 and a blue filter part B1 are formed in each pixel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display panel and an image display apparatus having a function of maintaining a display state of image information, and more particularly to an image display panel and an image display apparatus for forming an image by heating or the like.

[0002]

2. Description of the Related Art Conventionally, an electric address type liquid crystal display is most often used as a flat panel display. Electric address type liquid crystal display
Since they are smaller in volume and lighter than CRTs, they are used in various fields mainly for portable terminal devices. But,
A conventional electric address type liquid crystal display has a display resolution of 100 dpi or less and does not satisfy the minimum resolution of the human eye under use conditions. For this reason, the liquid crystal display has a problem in that when displaying fine characters and the like, a load is imposed on the visual ability of the user.

On the other hand, self-luminous displays such as CRTs and plasma displays also have a low display resolution like a liquid crystal display, and impose a burden on a user's visual ability. In addition, since the self-luminous display does not have a function of adjusting to an ambient lighting environment, it cannot maintain appropriate luminance, and this also imposes a burden on the visual ability of the user. In addition, a liquid crystal display using a backlight has the same problem in that it does not have a function of adjusting the surrounding illumination environment.

In addition, many displays require a few seconds to a few seconds.
The display screen is drawn at a speed of several tens of frames, and unnecessary energy is consumed when viewing still image information.

[0005] Examples of displaying a still image on an electric display include an electronic book displaying newspaper articles and dictionary data, and HTML (Hy
perText Markup Language) documents. In displaying a still image centering on character information, it is ideal to have optical characteristics similar to those of a normal printed matter. Optical characteristics of the printed material include a white scatterer having high reflectance, a high-contrast character display capability, and a low viewing angle dependency. Since paper most frequently used as a printing target is a reflector, it has a self-adjustment function in which the luminance changes according to a change in ambient illumination. The reflectance is more than 60% for newspaper and 80% for coated paper.
And high.

Therefore, when viewing in a bright place, the brightness is high and the burden on human visual ability is small. Furthermore, in the case of a printed matter, since the printed matter is formed with a high resolution of 300 to 600 dpi or more, image information is formed with a resolution exceeding the minimum resolution of human vision even when viewed directly at a close distance of 30 to 60 cm. Therefore, it can be recognized as a continuum, and in this respect too, the burden on visual ability is small.

On the other hand, a liquid crystal light valve system in which a driving circuit is formed on a Si crystal by IBM (Paul M. Al) is one that realizes high resolution on a display.
t; Conference Record of the 1997 International Disp
lay Research Conference and International Workshop
on LCD Technology and Emissive Technology (1997), M
-19). In this method, a high-resolution electrically-addressable reflective liquid crystal display using a processing technology and a processing device of a Si integrated circuit as it is is created. This display has a fine pixel pitch of 17 μm × 17 μm,
Assuming a direct view type, the chip resolution is 1500d
pi.

However, since the liquid crystal light valve type display always redraws an image, the power consumption is higher than that of a display having a memory function. In addition, since this display is manufactured using an LSI process on a Si substrate, a display larger than a Si wafer cannot be manufactured, and when a large direct-view type display is manufactured, cost increases. There is a problem that becomes. For this reason, IBM uses this display as a member of a projection display. Another problem is that the projection display does not have a self-adjustment function with respect to the ambient lighting environment, like the self-luminous display.

Therefore, a display for displaying a still image, which is of a reflection type, has a high luminance, and has a high resolution, is required. In a display for displaying a still image, when power consumption is considered, it is not necessary to refresh the screen except for rewriting display information. As a device that satisfies this requirement, there is a reflection type display that does not require refreshing by giving a liquid crystal display panel a memory function.

[0010] As a first example of such a display, M. Kent of Kent University. Some use the phase change of cholesteric liquid crystal performed by Pfeiffer et al. (Society fo
r Information Display International Symposium Dige
st of Technical Papers XXVI (1995), 706-). This display selects a focal conic mode as a scatterer and a planar mode with high transmittance depending on the applied voltage, and has a visible light absorbing layer made of a dye on the back of the display to provide high contrast and high reflection. The rate has been realized.

A second example is disclosed in Japanese Patent Laid-Open No. 1-250.
As described in Japanese Patent Application Laid-Open No. 926, 926, a liquid crystal display panel that can be addressed by a laser is provided to provide a high-resolution, high-contrast display.

As a third example, there is a spatial light modulator as a display which does not require fine processing of electrodes. This display is a display that collectively exposes image information or forms an image by high-definition drawing using a laser. Since the entire display is formed by a pair of electrodes facing each other, fine processing is not required.

However, in the first example, it is necessary to reduce the pixel size in order to realize a high resolution. For this purpose, the electrode panel must be miniaturized, which causes a problem that an adjacent electric field is affected by an electric field and a processing cost increases.

On the other hand, the second example is used as a projector member, and when viewed directly, paper white light scattered by liquid crystal or mirror reflected light without scattering is directly viewed. . For this reason, a monochrome image such as a printed matter cannot be formed, and the image is like a character written with white paint on a mirror.

The third example is also used as a projector member, and when viewed directly, an image has the same result as the second example. In order to solve the above-mentioned problem, the present applicant has previously filed Japanese Patent Application No. 9-348177.
In an image display plate having a function of maintaining a display state of image information, a phase transition accompanied by a change in reflectance and transmittance is caused by heating, and the state after the phase transition or the change in the orientation state is maintained by heating. Provided is an image display panel having an image recording layer on which information is formed, and a dielectric layer that absorbs visible light transmitted through the image recording layer.

As Japanese Patent Application No. 10-71890,
In an image display panel having a function of maintaining a display state of image information, an optical address layer that generates a photoelectromotive force at a specific wavelength, and a phase transition or an orientation according to a change in voltage distribution caused by the electromotive force of the optical address layer. An image recording layer in which the image information is formed by causing a change in state and maintaining the state in which the phase transition or the orientation state has changed, and an image recording layer formed between the image recording layer and the optical address layer And a dielectric layer that absorbs visible light transmitted through the substrate.

As a result, it is possible to obtain an image display panel which enables high-resolution display while being of a reflection type and is easy to manufacture.

[0018]

SUMMARY OF THE INVENTION However, Japanese Patent Application No. Hei 9-3
The image display plates of No. 48177 and Japanese Patent Application No. 10-71890 have a problem that only monochrome display is possible and color images cannot be displayed.

The present invention has been made in view of the above points, and has been made in view of the above circumstances. An image display plate capable of maintaining excellent image display characteristics and capable of displaying a color image with excellent reflection color and excellent quality, and It is an object to provide an image display device.

[0020]

According to the present invention, in order to solve the above-mentioned problems, in an image display plate having a function of maintaining a display state of image information, a phase transition accompanied by a change in reflectance and transmittance is caused by heating. And an image recording layer on which the image information is formed by maintaining the state after the phase transition, and visible light absorption formed on the back surface of the image recording layer and absorbing visible light transmitted through the image recording layer. And a color filter provided on the image recording layer on the side of the visible light incident surface of the image recording layer.

In such an image display plate, a portion to be displayed on the image recording layer is heated by using, for example, a laser beam to cause a phase transition accompanied by a change in reflectance and transmittance. The visible light transmitted through the image recording layer is absorbed by the visible light absorbing layer. Thereby, it is possible to display an image with a clear reflection color. Further, since a color filter is provided on the image recording layer on the side of the visible light incident surface, a clear color display of the reflected color becomes possible.

Since the state after the phase transition is maintained,
Once written, the displayed content can be maintained. Further, since switching for each pixel is unnecessary, high-resolution display can be performed without using fine electrodes.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram illustrating a schematic configuration of an image display device including the image display panel according to the first embodiment of the present invention. The image display device 10 mainly includes a light output device 11, a polygon mirror 12, a deflector 13, and an image display plate 20. The light output device 11 outputs the writing light 14. As the writing light 14, for example, an infrared laser is used. The writing light 14 is reflected by the rotating polygon mirror 12 and directed rightward in the drawing, and passes through the deflector 13 so as to be directed in a direction perpendicular to the plane of the drawing, and irradiates the image display plate 20. On the display surface of the image display panel 20, the brightness of the portion irradiated with the writing light 14 changes. Specific operation control of the image display device 10 will be described later.

FIG. 1 shows an image display panel 2 according to a first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a specific configuration of the reference numeral 0. Image display board 20
The front support 21, the color filter layer 22, the transparent electrode layer 23, the image recording layer 24, the transparent electrode layer 25, the rear support 26, and the visible light absorbing layer 27 are arranged in this order from the side of the direction X1 in which the human looks directly. Is formed. This image display board 2
For 0, the writing light 14 can be irradiated only from the direction Y1 opposite to the direct viewing direction X1.

A portion of the image recording layer 24 irradiated with the writing light 14 has a phase transition due to heat, and an image is formed on the portion. The transparent electrode layers 23 and 25 heat the image recording layer 24 when a DC voltage is applied, thereby promoting a phase transition. Further, by applying a voltage to the transparent electrode layers 23 and 25, the recorded image is erased. The front support 21 and the rear support 26 are formed to support the image recording layer 24. The visible light absorbing layer 27 absorbs visible light incident from the direction X1.
As a result, the portion where the image is recorded has a brightness different from that of the other portions, so that the image can be easily recognized by direct viewing from the direction X1.

Here, an RGB filter is used as the color filter layer 22, and a red filter portion R1, a green filter portion G1, and a blue filter portion B1 are provided for each pixel.
Are formed. The space between the filter portions is filled with a transparent member 28.

Next, specific examples of materials for forming these layers will be described. First, as the image recording layer 24, for example, a liquid crystal material is used as a material that undergoes a phase transition due to a temperature change or a voltage application. As the liquid crystal material, n-type nematic liquid crystal, n-type nematic liquid crystal / cholesteric mixed liquid crystal, p-type smectic liquid crystal, n-type smectic liquid crystal, chiral nematic liquid crystal, polymer dispersed liquid crystal, dispersed fine particle rotating system, electrophoretic material, etc. are used. it can.

The n-type nematic liquid crystal includes MBBA (n-
(p-methoxybenzylidene) -p-butylaniline), PAA
(P-azoxyanisole), APAPA (anisylidene para-a)
minophenyl acetate).

The n-type nematic liquid crystal / cholesteric mixed liquid crystal includes MBBA / CN (cholesteryl nonanoate).
) Mixed system, MBBA / EBBA (n- (p-pentoxybenzyli
dene) -p-butylaniline) / CN system, COC (cholester
yl oleyl carbonate) / MBBA mixed liquid crystal, COC /
EBBA (p-ethoxybenzylidene-p'-n-butylaniline)
Mixed liquid crystal, COC / PEBAB (p-ethoxybenzylidene-
p'-aminobenzonitorile) mixed liquid crystal, COC / MBBA
/ EBBA / PEBAB.

The p-type smectic liquid crystal includes CBOA
(N- (p-cyanobenzylidene) -pn- (octylaniline)), C
BOOA, AZ56, COB (cyano-octyl 4-4'biphen
yl), COOB, OCBP (octyl cyanobiohenyl),
There are PCBN, PCBD, Eutetic1, Eutetic2, and the like.

The n-type smectic liquid crystal includes PBBA
(P-butoxybenzylidene-pn-butylaniline), PBPA
(P-pentoxybenzylidene-pn-butylaniline), PBB
A (p-butoxybenzylidene-pn-hexylaniline), HBB
A (p-hexoxybenzylidene-pn-butylaniline), N, N
-dimethyl-Noctadecyl-3-aminopropyltrimethoxysilyl
and so on.

The liquid crystal becomes a cholesteric phase as one of the bistable states. At this time, it is preferable to prevent the wavelength in the visible light range from being diffracted and colored by the diffraction grating formed by the cholesteric phase.

The polymer dispersed liquid crystal is composed of a polymer material and a liquid crystal material. Polymer materials include polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, vinyl chloride / vinyl acetate / vinyl alcohol copolymer, vinyl chloride / acrylate copolymer, polyvinylidene chloride, vinylidene chloride / vinyl chloride copolymer Coalescence, vinylidene chloride-acrylonitrile copolymer, polyester, polyamide, polyacrylate, polymethacrylate, acrylate-methacrylate copolymer, silicone resin and the like are used. Also,
Hydroxy pivalic acid ester neo
pentylglycole, 2-hydoxy-2methyl-1phenylpropan-1-on
A UV crosslinking material such as e, or a UV curable resin may be mixed and used. Note that a ceramic cell may be used instead of the polymer material. As a ceramic cell / liquid crystal composite type display member, there is one described in JP-A-9-127492.

The chiral nematic liquid crystal includes the following materials.

[0035]

Embedded image

[0036]

Embedded image

As the liquid crystal material of the polymer dispersed liquid crystal, MB
BA, PAA, APAPA, PBBA, PBPA, HB
BA and others. The following material systems are also used.

[0038]

Embedded image

[0039]

Embedded image

The above-mentioned material system absorbs the writing light 14,
It is better to have the property of converting to heat. In some cases,
There is also a method of improving the conversion efficiency by mixing an organic or inorganic material which hardly affects the physical properties of the liquid crystal, has a high transmittance in the visible light region, and absorbs in the infrared region.

Among these, materials absorbing infrared rays include benzenedithiol metal complexes, squarylium compounds, bissquarylium compounds, croconium compounds, phthalocyanine compounds (for example, vanadium oxide phthalocyanine, etc.), and fluorine-containing phthalocyanine compounds (for example, As 3,5,6-dodecafluoro-4-tetrakis (p
-(2-methoxy) ethoxycarbonylphenoxy) zinc phthalocyanine, 3,5,6-dodecafluoro-4-tetrakis (p
-(2-methoxy) ethoxycarbonylphenoxy) oxyvanadium phthalocyanine, 3,6-octafluoro-4,5-
Octakis (p- (2-methoxy) ethoxycarbonylphenoxy) zinc phthalocyanine, etc.), phthalonitrile compounds (for example, 3,6-difluoro- (4-n-butoxy) -5- (n-
Butylthio) phthalonitrile (BuO) (BuS) F2PN, 3,6-difluoro- (4-phenoxy)-(5-phenylthio) phthalonitrile (PhO) (PhS) F2PN, etc., polymethine-based compounds, benzothiobrillium Compounds, naphthalocyanine compounds (eg, 2,3-naphthalenedicarboxylic acid diamide, bis (2-ethylhexyloxy) (2,3-naphthalocyanato) silicon, etc.), and quinone compounds.

Examples of the inorganic compound include silicon dioxide, magnesium fluoride, chromium oxide, nickel, and aluminum. In order to keep the thickness of the image recording layer 24 uniform, it is necessary to introduce a spacer (not shown). The spacer includes glass or resin beads. Alternatively, the spacer may be prepared by pattern etching after the volume of the thin film is increased.

Next, the materials used for the transparent electrode layers 23 and 25 include SnO _x and ITO (InSn) as inorganic materials.
_y O _x ), InO _{x and the} like, and on the other hand, organic materials include polyaniline and the like. The transparent electrode has a high transmittance in the visible light region, a resistivity that does not cause a delay that would hinder the voltage pulse applied to the liquid crystal, and a material that does not cause a chemical reaction with the liquid crystal material. It is necessary to be. The transparent electrode layers 23 and 25
It is better if it has a high absorption coefficient with respect to 4 and a property of converting it into heat. When the image recording layer 24 does not absorb the wavelength of the writing light 14, it is necessary to convert the light into heat in the transparent electrode layers 23 and 25 and transmit the heat to the liquid crystal layer.

The front support 21 needs at least the following characteristics. First, the transparent electrode layer 23, the image recording layer 2
4. It is necessary to have a strength capable of supporting the transparent electrode layer 25, the rear support 26, and the visible light absorbing layer 27, and a strength enough to withstand the force generated when writing or erasing an image and the impact during transport. Further, the front support 21 needs to be designed to have a material and a thickness that transmit visible light at a sufficient ratio. In order to enhance the impact resistance, a flexible plastic film is used. On the other hand, when strength is required, a rigid plastic sheet or glass is used.

Since the front support 21 is located between the laser light source and the image recording layer 24, the front support 21 needs to be formed of a material through which the writing light 14 can be sufficiently transmitted. In this case, for example, glass, a plastic sheet, or the like is appropriate. Alternatively, visible light or writing light 1
In order to enhance the transmittance of both 4 and visible light, the layer having an anti-reflection effect or the film thickness capable of exhibiting the anti-reflection effect is adjusted as necessary, or the anti-reflection effect is increased by combining both. You may.

When writing is performed by irradiating the writing light 14 from the direction Y1, the front support 21 absorbs all of the writing light 14 so as not to leak outside.
It is necessary to provide one or both functions of reflecting the writing light 14.

On the other hand, the rear support 26 is
Has a sufficient strength, the film thickness of the image recording layer 24 is kept uniform, and the strength is such that the transparent electrode layer 25 and the visible light absorbing layer 27 are not broken by the stress due to the heat of writing. Good. In some cases, in order to enhance the transmittance of the writing light 14, as in the case of the front support 21, a layer having an antireflection effect or a film thickness capable of exhibiting the antireflection effect is adjusted, or a combination of both is used. The antireflection property may be enhanced.

As the visible light absorbing layer 27, when irradiating the writing light 14 from the direction X1 side, various materials that absorb visible light can be used. One example is carbon resin. On the other hand, when the writing light 14 is irradiated from the direction Y1, the visible light absorbing layer 27
It is necessary to have a high transmittance for the wavelength of, and in this case, an inorganic material or a pigment such as black glass is used. As black glass, IR-76 and IR-8 manufactured by Hoya Co., Ltd.
0, IR-85, RM-86, RM-90, RM-10
0 and so on. On the other hand, dyes include anthraquinone dyes and quinophthalone dyes. When one dye cannot absorb the entire wavelength range of visible light, there is a method using a mixture of two or more dyes. Besides this, B
Black materials such as i (bismuth) -SiOx and carbon black resin can be used.

When the dye is used as the visible light absorbing layer 27, the lamination method is as follows. A high molecular polymer in which the dye is uniformly dispersed is dissolved in a solvent, coated and dipped on the rear support 26, and then dried to form a layer. There is a method of forming. In order for the visible light absorbing layer 27 to absorb visible light, it is necessary to have a sufficient film thickness. Alternatively, it can be formed by laminating low molecular materials by a method such as vapor deposition.

Next, the principle of color display on the image display plate 20 having such a configuration will be described. Now, for example, focusing on the blue filter section B1, when the writing light 14 incident from the front support 21 side passes through the blue filter section B1 of the color filter layer 22, the blue filter section B1
Absorbs light other than blue light, and only blue light
Reach inside 4. When the image recording layer 24 is in the light scattering state, the light of the blue component is scattered and
2 and again return. At this time, the red filter unit R1,
Part of the light transmitted through the green filter portion G1 is
4 reach the blue filter portion B1 due to scattering generated inside, but are absorbed by the blue filter portion B1. Therefore, only blue is reflected to the outside. When the image recording layer 24 is in the transmission state, the light of the blue component is
There is almost no reflected light.

Similar color selection occurs in the other red filter section R1 and green filter section G1. Therefore, by controlling the irradiation of the writing light 14 on each pixel, red, green, and blue can be displayed. Also, by combining the colors, a color image of a plurality of colors can be displayed.

Next, a method for forming the color filter layer 22 on the image display panel 20 will be described. As a method for forming the color filter layer 22, conventionally known methods, for example, a dyeing method, a pigment dispersion method, a printing method, and an electrodeposition method can be roughly classified into four types of methods.

For example, a color filter formed by a dyeing method forms a dyeable photosensitive film on the front
A dye pattern is formed by pattern exposure through a photomask in alignment with one of the blue phosphor layers and development. After that, the color line process is performed by performing a side line process, and the procedure is repeated from the formation of the dyeable photosensitive film to form pixel patterns of the second and third colors. Next, a color filter layer 22 is formed by providing a transparent top coat layer on the surface for protection and flattening of the pixel portion.

In the printing method, each pixel is printed in alignment with the red, green, and blue phosphor layers using an ink in which a pigment is dispersed in a thermoplastic resin or an ultraviolet curable resin, and the color filter layer 22 is formed. Make it.

Further, in the electrodeposition method, the front support 21 is used.
Is formed on the substrate, and this is aligned with any of the red, green and blue phosphor layers and patterned to expose the ITO film. When a current is applied to an electrodeposition solution in which a pigment is dispersed in a transparent and stable polymer into which a carboxyl group or the like has been introduced, the polymer adheres to the exposed ITO film. This is repeated for the three colors of red, green and blue to form the color filter layer 22. In the case where a black matrix is provided as in the image display panel 40 of a third embodiment to be described later, the above process may be repeated after forming the black matrix to obtain a color filter containing Bk.
Since the ITO film to which the polymer has been attached first is insulated by the polymer, color mixing with other colors does not occur.

In the pigment dispersion method, a pigment is dispersed in a film-forming material such as an acrylic resin with a dispersant or the like, applied on a substrate, and dried to form a colored layer. A resin is applied, dried, aligned with any of the red, green, and blue phosphor layers using a mask, exposed, and developed to form a resist pattern. The colored layer in the portion where the resist was removed was removed by etching to form a pattern consisting of the colored layer and the resist layer, and then the unnecessary resist on the colored layer was peeled off, and this was repeated to form a color filter. Finalize.

Further, a photopolymerizable monomer and a photopolymerization initiator or a photosensitizer are added to a color composition comprising a pigment and a vehicle thereof to form a photocolor composition, which is coated on a substrate and dried. Exposure may be performed, and this may be repeated to form a color filter. In this case, a photosensitive agent includes a bisazide compound, a diazo compound and the like, and a photopolymerization initiator includes acetophenone and benzyldimethyl ketal.

If the color filter layer 22 requires heat resistance, it may be formed by any of the above methods, but the material must have heat resistance, and a heat-resistant pigment or colored glass may be used. A paste obtained by dispersing a low-melting glass frit (PbO, B ₂ O ₃ , SiO _2, etc.) in a solution of a resin that can be fired at a low temperature such as ethyl cellulose, nitrocellulose, polyvinyl alcohol, or an acrylic resin is used. Further, the paste may be formed by a photolithography method using a photosensitive paste obtained by adding a photosensitive resin to the paste.

The heat-resistant pigments used above include the following. There are many types of heat-resistant pigments, but typical ones are iron (red), manganese aluminate (pink), antimony-titanium-chromium (orange), iron-chromium-zinc (brown), iron System (brown), titanium-chromium system (yellow-brown), iron-chromium-zinc system (yellow-brown), antimony-titanium-chromium system (yellow), zinc-
Vanadium (yellow), zirconium-vanadium (yellow), vanadium-chromium (yellow), cobalt (blue), cobalt aluminate (black), vanadium-zirconium (black), cobalt-chromium-iron (Black) and the like, and the color tone can be adjusted by mixing these. And, it is desirable that the content of the particles having a particle diameter of 1 μm or more is 10% by weight or less. That is, if there are many particles having a large particle diameter, the transmittance is reduced and the reflectance is reduced. Further, the particle size is 0.01 to
It is desirable that 0.7 μm particles account for at least 20% by weight of all particles.

The heat-resistant colored glass used above includes the following. There are many types of colored glass due to its colored structure, and the color changes with the same raw material depending on conditions. As an example, the frit is mainly composed of potassium lead glass containing silicon, lead oxide, potassium oxide, boric acid, aluminum fluoride, arsenic oxide, and the like, and as raw materials, quartzite, leadtan, yellow lead oxide, lead white, Potassium saltpeter, boric acid, borax,
Sodium bicarbonate, fluoride and the like are used. As coloring agents, arsenous acid (white), copper oxide (green), cobalt oxide (blue), potassium dichromate (yellow), antimony oxide (yellow), iron oxide (brown), manganese dioxide (purple), nickel oxide (Purple), gold chloride (red), sodium uranate (orange), selenium red (reddish red) and the like are combined and mixed. In the present embodiment, a mixture obtained by mixing, heating, melting and vitrifying the mixture and then cooling and pulverizing the mixture is used.

In the above description, the method of directly forming the color filter layer 22 on the front support 21 has been described.
An image display plate 20 of the present embodiment may be formed by attaching a separately manufactured color filter to the support 21 on the front side.

These color filters are used for the image recording layer 24.
Is in contact with the material of the image recording layer 24. In the above description, an RGB color filter is used. Alternatively, a color filter of white, yellow, blue, and black may be used by using two color filters of yellow (Y) -blue (B).
There is also an example of performing color display. It is also possible to use cyan (C), magenta (M), and yellow (Y) color filters instead of RGB.

An advantage of the CMY color filters is that the reflectance in displaying white is higher than that of the RGB color filters. However, on the other hand, when expressing red, green, and blue, there is a problem that a white component is mixed in each color. Therefore, it is necessary to use an appropriate color filter according to the application.

Next, returning to FIG. 2, a specific example of an image information recording method by the image display device 10 using the image display plate 20 having the above configuration will be described. The image recording using the writing light is performed by irradiating the entire surface or scanning irradiation with the image signal, character information, code signal, line drawing signal information, etc., by changing the intensity or pulse of the writing light to ON / OFF. For recording an image, a writing light 14 having a high light intensity is used. As a light source of the writing light 14, an argon laser (wavelength: 514.488 nm),
Helium laser (wavelength 633 nm), semiconductor laser (wavelength 780.810 nm, 1310 nm, 1340 nm,
For example, 1480 nm, 1550 nm, or a YAG laser (wavelength: 1064 nm) can be used. There is also a method of irradiating a non-coherent light such as a light emitting diode or a halogen lamp by condensing it with a lens system.

The recording of an analog image is performed by writing light 1
The recording of digital images such as characters, codes, and line drawings is performed by controlling the writing light 14 on and off. It is also possible to convert the image information into halftone information and record it.

The scanning irradiation method of the writing light 14 is as follows.
By operating the polygon mirror 12 and the deflector 13 while converging and irradiating the image recording layer 24 shown in FIG. 1 in the form of a spot, the writing light 14 is scanned to record an image.

Each part of the image display panel 20 is irradiated with the writing light 14 for a short time by the scanning of the writing light 14. Thereby, the image recording layer 24 and the transparent electrode layers 23, 2
5, light absorption occurs, resulting in a local temperature rise. Therefore, the temperature of the laser-irradiated portion of the image recording layer 24 increases, and a phase transition occurs. Then, when the irradiation with the writing light 14 is completed, the irradiated portion of the image recording layer 24 is in a phase state different from the initial state because of rapid cooling. That is, there are two cases: a case where the transmittance in the initial state is high and the scattering state is generated by the irradiation of the writing light 14, and a case where the initial state is a scattering state and the transparent state is formed by the irradiation of the writing light 14.

By applying a DC voltage between the transparent electrode layers 23 and 25 at the time of irradiation with the writing light 14, the efficiency of the phase transition can be increased. At this time, if the drawing position of the laser deviates from a target filter portion of the color filter layer 22, a desired pixel cannot be formed. For this reason,
A mechanical mechanism that does not shift the drawing position, or an adjustment mechanism that adjusts the drawing position may be introduced.

The image display plate 30 on which an image has been recorded in this manner is placed under the illumination light or sunlight in the direction X in FIG.
1, the scattered portion of the image recording layer 24 looks red, green, or blue according to the color filter at that position, and the transparent portion looks black because the visible light absorbing layer 27 at the rear transmits therethrough. Thus, a color image can be displayed.

The size of the spot on which an image is formed depends on the irradiation time of the writing light 14, the intensity of the laser beam, the intensity distribution of the laser beam spot, the image recording layer 24 and the transparent electrode layer 2 and the like.
3, 25, the writing light 14 is applied to the image recording layer 24.
And the amount of loss due to reflection and absorption before reaching the transparent electrode layers 23 and 25. The size of the spot must be equal to or smaller than the size of the color filter. A resolution of 300 dpi or more can be realized by miniaturizing the color filter in consideration of these physical quantities. The gradation is determined by the total energy to be irradiated, and is expressed by one or both of the area ratio between the scattering state and the transmission state and the transmittance in the scattering state.

The image recorded on the image recording layer 24 can be erased by applying a voltage between the transparent electrode layers 23 and 25. The pattern of the applied voltage includes a DC voltage, a sine wave, a triangular wave, a pulse wave, or a composite wave of these. Further, the period of the voltage change, the pulse width, and the like differ depending on the type of the liquid crystal material, and an appropriate one is selected by experiments or the like.

FIG. 3 is a sectional view showing a specific structure of the image display panel according to the second embodiment of the present invention. Note that the same components as those of the image display panel 20 of the first embodiment are denoted by the same reference numerals and description thereof is omitted. The image display plate 30 according to the present embodiment includes:
It is configured on the assumption that the writing light 14 is emitted from the direction Y2 opposite to the direct viewing direction X2. Image display board 30
In the figure, the color filter layer 22 is formed on the front side of the front support 21. In addition, an infrared shielding layer 31 is formed between the front support 21 and the transparent electrode layer 23.

The infrared blocking layer 31 needs to have a function of reflecting or absorbing the infrared writing light 14 or both functions. On the other hand, the infrared shielding layer 31
It is necessary to have high transmittance in all wavelength regions of visible light. Materials that absorb infrared rays and transmit visible light include HA-20, HA-30, and HA-30 manufactured by Hoya Corporation.
There are glass materials such as -50. On the other hand, as a plastic material, a plastic film containing UCF manufactured by Kurehallentech Co., or an anthraquinone derivative, a phthalocyanine derivative, a naphthalocyanine-based compound, a cobalt complex, a dithiol-based metal complex, a squarium compound, an immonium-based compound, an acetylene derivative, etc. is there.

Further, the infrared light blocking layer 31
By having a high reflectivity for 4
The reflected laser light is applied to the image recording layer 24, the transparent electrode layer 23,
25 can be re-irradiated, and the writing efficiency is improved.

The materials and forming methods of each layer other than the infrared shielding layer 31 and the method of writing an image are described in the first section.
The same thing as the image display plate 20 of the form can be applied. FIG.
FIG. 7 is a cross-sectional view illustrating a specific configuration of an image display panel according to a third embodiment of the present invention. Note that the same components as those of the image display panel 20 of the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the image display panel 40 of the present embodiment, the writing light 14 is emitted from a direction Y3 opposite to the direct viewing direction X3. This image display panel 40 includes a color filter layer 41 instead of the color filter layer 22 of the image display panel 20 of FIG. The color filter layer 41 is provided between the red filter portion R2, the green filter portion G2, and the blue filter portion B2 of each pixel.
A black matrix 41a is included.

By providing the black matrix 41a, it is possible to prevent multiple reflection light and leakage light generated at the interface between adjacent color filters and to make the image clear.

In the present embodiment, the same materials as those in the first embodiment can be applied to the materials, forming methods, and image writing methods of the respective layers. FIG. 5 is a sectional view showing a specific configuration of the image display panel according to the fourth embodiment of the present invention. Note that the same components as those of the image display panel 20 of the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the image display panel 50 of the present embodiment, the writing light 14 is emitted from a direction Y4 opposite to the direct viewing direction X4. The image display panel 50 includes a color filter layer 51 and a front support 2.
1 is provided on the outermost surface. The color filter layer 51 includes a black matrix 51a between the red filter portion R3, the green filter portion G3, and the blue filter portion B3 of each pixel.

By providing the black matrix 51a, it is possible to prevent multiple reflection light and leakage light generated at the interface between adjacent color filters and to make the image clear.

In the present embodiment, the same materials as those in the first embodiment can be applied to the material, forming method, image writing method, and the like of each layer. FIG. 6 is a sectional view showing a specific configuration of the image display panel according to the fifth embodiment of the present invention. In the image display panel 60 of the present embodiment, in the direct viewing direction X
The writing light 14 is irradiated from a direction Y5 opposite to the direction Y5. This image display panel 60 is the image display panel 5 of the fourth embodiment.
0 has a rear support 61 having a visible light absorbing function. Here, the same components as those of the image display panel 50 are denoted by the same reference numerals, and description thereof is omitted. A dye that transmits the writing light 14 and absorbs visible light is added to a part or the surface of the rear support 61. As the dye, the same material as that described for the visible light absorbing layer 27 in FIG. 1 can be used. Further, the black glass described for the visible light absorbing layer 27 in FIG. 1 may be used as the support.

In this embodiment, the same materials as those of the respective layers, the forming method, the image writing method, and the like can be applied to the image display plate 20 of the first embodiment. By the way, the black matrix 41a, shown in FIGS.
The method for forming 51a may be any conventionally known method, for example, a method using a chromium metal film or a method using a photosensitive resin in which carbon, a light-shielding pigment, or the like is dispersed. The black matrix made of a metal film such as chromium is formed by forming a metal film on any surface of the front support substrate by a method such as vapor deposition, and then forming the metal film by a photolithography method using a photoresist and an etching process.

On the other hand, in the method using a photosensitive resin in which carbon or a light-shielding pigment is dispersed, a photosensitive resin layer in which a light-shielding pigment or the like is dispersed is applied to any of the front supports 21 by coating or printing. Form on the surface.

Further, as disclosed in JP-A-4-13105 and JP-A-63-309916, a black matrix can be formed by using a light-shielding photosensitive material in which pigments of a plurality of hues are combined. It is possible. Further, Japanese Patent Application Laid-Open Nos. H04-40420 and H4-1903.
As described in JP-A-62-62, a black matrix of a light-shielding material can be formed by mixing a plurality of organic pigments with carbon black or by mixing a plurality of organic pigments with an organic black pigment.

The deflector 13 shown in FIG.
Polygon mirror, galvanometer mirror, or acousto-optic (A
O) The effect can also be used. Alternatively, the writing light 14 can be relatively scanned by sliding the image display plate 20 side by a slide mechanism (not shown).

Further, both the deflector and the slide mechanism can be combined. Further, a mechanism for arbitrarily sliding the light output device 11 as a writing light source in a two-dimensional direction may be provided.

FIG. 7 is a diagram showing another example of the configuration of the image display device. In the image display device 70, a movable mirror 71 is provided instead of the deflector 13 in FIG. 2, and the writing light 14 is scanned by sliding the mirror 71. In FIG. 7, elements having the same functions as those in FIG. 2 are denoted by the same reference numerals.

The image display plates 20, 30, 40, 50, and 60 of the first to fifth embodiments are of a type that forms an image by causing a phase transition in the image recording layer 24 by heating with the writing light 14. Although a color filter layer has been shown, a color filter layer may be provided on an image display plate of a type in which phase transition is caused by photovoltaic power.

FIG. 8 is a cross-sectional view showing an example of a structure in which a color filter layer is formed on an image display panel of a type in which phase transition is caused by photovoltaic power. On the image display panel 80, the rear support 81,
An electrode layer 82, an optical address layer 83, a dielectric layer 84, an image recording layer 85, a transparent electrode layer 86, and a front support 87 are formed. Also, the transparent electrode layer 86 and the front support 87
Between them, a color filter layer 88 is formed.
The image display plate 80 can be irradiated with the writing light 14 only in the direction Y6 opposite to the direct viewing direction X6.

On the optical address layer 83, the write light 14
Photocarriers are generated in the area irradiated with the light, and the resulting change in voltage distribution causes a phase transition or a change in the alignment state in the image recording layer 85, and an image is formed in that area. The electrode layer 82 and the transparent electrode layer 86 heat the image recording layer 85 when a DC voltage is applied, thereby promoting a phase transition or a change in an alignment state. Also,
By applying a voltage to the electrode layer 82 and the transparent electrode layer 86, the recorded image is erased. Rear support 81
The front support 87 is formed to support the image recording layer 85. The dielectric layer 84 enters from the direction X6 and absorbs the incident visible light. As a result, the portion where the image is recorded has a brightness different from that of the other portions, so that the image can be easily recognized by direct viewing from the direction X6.

Further, since the image is directly viewed through the color filter layer 88, a color image can be recognized. Here, an RGB filter is used as the color filter layer 88, and a red filter portion R4, a green filter portion G4, and a blue filter portion B4 are formed for each pixel.
The space between the filter portions is filled with a transparent member 88a.
The principle of color display by the color filter layer 88 is the same as that of the image display plate 20 of FIG.

It should be noted that a black matrix can be used instead of the transparent member 88a. Further, the position of the color filter layer 88 can also be arranged on the front surface of the front support 87 or the like.

[0091]

Next, an embodiment of the image display panel 60 shown in FIG. 6 will be described. First, as a material of the rear support body 61 of the image display panel 60, a 40 mm square infrared transmitting glass HA-20 made of squirt was used. On this surface, a transparent electrode layer 25 made of ITO having a thickness of 180 nm was formed by a sputtering method.

On the other hand, as a material of the front support 21, 40
Infrared absorbing glass RM-86 manufactured by Hoya of mm square was used. The red filter portion R3 and the green filter portion G for RGB are formed on the surface of the front support 21 by lithography.
3. A color filter layer 51 having a blue filter portion B3 and a black matrix 51a was formed. Further, a transparent electrode layer 2 made of ITO having a thickness of 180 nm is formed on the side opposite to the surface on which the color filter layer 51 is formed by sputtering.
3 was formed.

Next, the surface of the transparent electrode layer 23 has a diameter of 18
After applying a glass bead of mm to form a spacer, a curable epoxy resin was applied to the edge of the transparent electrode layer 23 for 10 hours and bonded to the transparent electrode layer 25. At this time, a place where no epoxy resin was present at about 10 mm was formed at two positions facing each other when viewed vertically from the front support 21 side, and this was used as a liquid crystal injection port. When the epoxy resin was cured, a sufficient pressure was applied to each of the supports 21 and 61 so that the distance between the image recording layers 24 became uniform.

Further, 45 Wt% of MBBA, 45 Wt
% EBBA and 10 Wt% CN mixed liquid crystal were injected from the injection port while heating so as not to generate bubbles. After the injection, the injection port was sealed with a high-speed curing type epoxy resin for 5 minutes. After heating this on a hot plate heated to 70 ° C., a voltage of 250 Hz and 40 V was applied while heating, and it was allowed to cool to room temperature while applying the voltage, and the image recording layer 23 became transparent. , Image display board 6
0 is completed.

Next, the completed image display plate 60 was set on the image display device 10 of FIG. 2 so that the laser light was irradiated from the rear support 61 side instead of the image display plate 20.
Here, the optical output device 11 has a laser diode FLD148G3NL-C manufactured by Fujitsu (wavelength 1480 nm, output 1).
00mW). Then, the writing light 14 output from the light output device 11 is deflected rightward in the drawing by the polygon mirror 12 and deflected in the direction perpendicular to the plane of the drawing by the deflector 13, and is substantially perpendicular to the surface of the rear support 61 of the image display panel 60. Was made incident.

The incident writing light 14 is applied to the image recording layer 2.
4 and the transparent electrode layers 23 and 25, thereby causing the image recording layer 24 to undergo phase transition and become cloudy, and the sub-pixel at the cloudy position was displayed in color with the color of its filter portion. Thus, a color image having a high resolution of 300 dpi was formed. After image formation, a voltage of 250 Hz and 40 V is applied for 1
By applying for 2 seconds, the image was erased and returned to the original state.

As described above, it is possible to realize a high-resolution, high-contrast, rewritable reflective display having a memory function of image information. Further, the image display panel 60 of FIG.
Then, the laser beam was radiated from the rear support 61 side instead of the image display plate 20. Again, the optical output device 11 has a laser diode FLD148G manufactured by Fujitsu.
3NL-C (wavelength 1480 nm, output 100 mW) was used. Then, the writing light 14 output from the light output device 11 was deflected by the polygon mirror 12 in the direction of the image display panel 60, reflected by the mirror 71, deflected in the vertical direction, and irradiated to the image display panel 60. At this time, the mirror 71 is moved at a constant speed.
Are set so as to be shifted by one pixel in the vertical direction when the next line is drawn.

The writing light 14 was made to enter the surface of the image display panel 60 almost perpendicularly, and the light output device 11 was emitted only when the image recording layer 24 was changed in phase. Writing light 14
Is absorbed by the image recording layer 24 and the transparent electrode layers 23 and 25, whereby the image recording layer 24 undergoes a phase transition and becomes cloudy.
Thus, an image was formed because it had a high resolution of 300 dpi. After the image was formed, the image was erased by applying a voltage of 250 Hz and 40 V for 1 second, and the image was restored.

[0099]

As described above, in the present invention, a phase transition accompanied by a change in reflectance and transmittance is caused by heating,
And an image recording layer on which image information is formed by maintaining the state after the phase transition, a visible light absorbing layer formed on the back surface of the image recording layer and absorbing visible light transmitted through the image recording layer, and image recording. A color filter provided on the incident surface side of visible light of the layer is formed, so that a portion to be displayed on the image recording layer is heated by using, for example, a laser beam, so that a reflected color image is clear. Display becomes possible.

Since the state after the phase transition is maintained,
Once written, the displayed content can be maintained. Further, since switching for each pixel is unnecessary, high-resolution display can be performed without using fine electrodes. Therefore, the manufacturing is simplified and the cost can be reduced.

Further, the visible light transmitted through the image recording layer can be absorbed by the visible light absorbing layer on the back surface of the image recording layer, and can be directly viewed from the front side of the liquid crystal display panel. Display can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a specific configuration of an image display panel according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of an image display device including the image display panel according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a specific configuration of an image display panel according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a specific configuration of an image display panel according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a specific configuration of an image display panel according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a specific configuration of an image display panel according to a fifth embodiment of the present invention.

FIG. 7 is a diagram illustrating another configuration example of the image display device.

FIG. 8 is a cross-sectional view illustrating an example of a configuration in which a color filter layer is formed on an image display panel of a type in which phase transition is caused by photovoltaic power.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image display apparatus 11 Optical output device 12 Polygon mirror 13 Deflector 14 Writing light 20 Image display panel 21 Front support 22 Color filter layer 23, 25 Transparent electrode layer 24 Image recording layer 26 Back support 27 Visible light absorption layer

Claims (6)

[Claims] 1. An image display panel having a function of maintaining a display state of image information, wherein a phase transition accompanied by a change in reflectance and transmittance is caused by heating, and the image after maintaining the state after the phase transition is maintained. An image recording layer on which information is formed, a visible light absorbing layer formed on the back surface of the image recording layer and absorbing visible light transmitted through the image recording layer, and an incident surface side of the visible light of the image recording layer An image display panel comprising: a color filter provided in: 2. The image display panel according to claim 1, wherein the color filter has a light blocking portion. 3. The image display panel according to claim 1, wherein said image recording layer is made of a liquid crystal material. 4. An image display panel having a function of maintaining a display state of image information, wherein a phase transition or a change in an orientation state occurs in accordance with a change in voltage distribution caused by photovoltaic power of an optical addressing layer, and An image recording layer on which the image information is formed by holding a state in which the orientation state has changed afterward, and formed between the image recording layer and the optical addressing layer and absorbs visible light transmitted through the image recording layer. An image display panel comprising: a dielectric layer to be formed; and a color filter provided on the image recording layer on the side of the visible light incident surface. 5. An image display device for displaying image information, wherein a phase transition accompanied by a change in reflectance and transmittance is caused by heating, and the image information is formed by maintaining the state after the phase transition. An image recording layer, a visible light absorbing layer formed on the back surface of the image recording layer and absorbing visible light transmitted through the image recording layer, and a color provided on the visible light incident surface side of the image recording layer. An image display plate having a filter, and image recording means for recording an image to be displayed by locally performing a heating sufficient for a substance contained in the image recording layer to undergo a phase transition. An image display device characterized by the above-mentioned. 6. An image display device for displaying image information, wherein a phase transition or a change in an alignment state occurs in accordance with a change in voltage distribution caused by photovoltaic power of an optical addressing layer, and after or after the phase transition. An image recording layer in which the image information is formed by maintaining a changed state, and a dielectric layer formed between the image recording layer and the optical address layer and absorbing visible light transmitted through the image recording layer And an image display panel having a color filter provided on the visible light incident surface side of the image recording layer, and a substance contained in the image recording layer having a phase transition or a change in alignment state sufficient to cause a change. An image display device comprising: an image recording unit that records an image to be displayed by locally generating light carriers.