JP2000267601A - Image display board and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reproduce white color with high reflectance by arranging a color filter placed between a 1st image recording layer and a 2nd image recording layer, and a visible light absorbing layer which absorbs visible light transmitting each image recording layer of the 1st image recording layer and the 2nd image recording layer. SOLUTION: This image display board 20 is formed of an image recording layer 23 for recording a white component, transparent electrodes 22a, 23b for applying a voltage to the image recording layer 23a, a color filter 24 for generating red, blue, and yellow, an image recording layer 23b for recording other components than black and white, transparent electrodes 22c, 22d for applying a voltage to the image recording layer 23b, and a visible light absorbing layer 27 for absorbing visible light. Image recording is performed by irradiating the image display board two times with a light beam for writing of which the direction is determined to the image display board. Thereby, it is possible to reproduce white color by the light directly reflected from the image recording layer 23a. Thus, white color with high reflectance can be reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display plate and an image display device having a function of maintaining a display state of image information, and more particularly to an image display plate and an image display device for forming an image by phase transition of a crystal.

[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 (H) which has been rapidly developing in recent years.
hyper Text Markup Languag
e) Documents and the like. 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. The paper most frequently used for printing is
Since it is a reflector, it has a self-adjusting function in which the luminance changes in accordance with changes in ambient lighting. In addition, the reflectance is 60
%, And 80% for coated paper.

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 it is formed with a high resolution of 300 to 600 dpi or more, even when directly viewed at a close distance of 30 to 60 cm, image information is formed with a resolution exceeding the minimum resolution of human vision. 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 or 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 that 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. Therefore, the applicant of the present application has previously filed Japanese Patent Application No.
No. 107451, in order to solve the above-mentioned problem, an image recording layer in which image information is formed by generating a phase transition accompanied by a change in reflectance and transmittance by heating and maintaining a state after the change, The present invention provides an image display plate having a visible light absorbing layer that absorbs visible light transmitted through the device, a color filter, and an image display device for driving the image display plate.

[0016]

However, in the image display apparatus provided above, there is a point to be improved in the reflectance of white when displaying a color image.

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

[0018]

According to the present invention, in order to solve the above-mentioned problems, an image display plate having a function of maintaining a display state of image information has a pair of upper and lower transparent electrodes,
A first image recording layer for recording the image information by maintaining the phase transition state by generating a phase transition accompanied by a change in transmittance and reflectance by heating, and a pair of upper and lower transparent electrodes, A second image recording layer that records the image information by maintaining the phase transition state, the second image recording layer recording the image information, the second image recording layer, and the second image recording layer. A color filter positioned between the image recording layer, the first image recording layer and the second
And a visible light absorbing layer that absorbs visible light transmitted through the image recording layer.

Here, the first image recording layer records white image information, and the transparent electrode layer comprises the first image recording layer and the second image recording layer.
A voltage is applied to the image recording layer, the color filter colors the displayed image, and the visible light absorbing layer absorbs visible light transmitted through the second image recording layer.

An image display device having a function of maintaining a display state of image information has a pair of upper and lower transparent electrodes, and generates a phase transition accompanied by a change in transmittance and reflectance by heating. A first image recording layer for recording the image information by maintaining the state, and a pair of upper and lower transparent electrodes, wherein a phase transition accompanied by a change in transmittance and reflectance is caused by heating, and A second image recording layer for recording the image information by holding the first image recording layer, a color filter positioned between the first image recording layer and the second image recording layer, and a first image recording layer. An image display plate having a layer and a visible light absorbing layer that absorbs visible light transmitted through the second image recording layer; and storing the image information in the first image recording layer and the second image recording layer. Image recording hands to record When the image display apparatus characterized by having a are provided.

Here, the image display plate stores a color image, and the image recording means records image information on the image recording plate.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic configuration diagram of the image display device 10 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 as light guiding means, and a deflector 1 also as light guiding means.
3 and an image display panel 20.

FIG. 1 is a sectional view showing the structure of the image display panel 20 according to the first embodiment of the present invention. The image display panel 20 includes a front support 21, a transparent electrode layer 22a, an image recording layer 23a, a transparent electrode layer 22b, a color filter 24, a dielectric layer 25, and a transparent electrode layer 22c in order from the side of the direction X1 in which the human looks directly. , Image recording layer 23b, transparent electrode layer 22
d, the rear support 26 and the visible light absorbing layer 27 are arranged.

As the color filter 24, here, RG
A B filter is used, and a red filter unit R is provided for each pixel.
1, a green filter portion G1 and a blue filter portion B1 are formed. Each filter for each pixel is filled with a transparent member 24a.

Next, specific examples of the materials forming these layers will be described. First, for the image recording layers 23a and 23b, for example, a liquid crystal material is used as a material that undergoes a phase transition due to a temperature change or 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.

In the p-type smectic liquid crystal, CBOA is used.
(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 display member, there is a member described in Japanese Patent Application Laid-Open No. 9-127492.

The following materials are used as the chiral nematic liquid crystal.

[0033]

Embedded image

[0034]

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.

[0036]

Embedded image

[0037]

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 diamide, bis (2-ethylhexyloxy) (2,3-naphthalocyanate) silicon, etc.), quinone compounds, etc. .

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 layers 23a and 23b uniform, it is necessary to introduce a spacer (not shown). The spacer includes glass or resin beads. Alternatively, after depositing a thin film, pattern etching may be performed to produce a spacer.

Next, the transparent electrode layers 22a, 22b, 22
The materials used for c and 22d include Sn as an inorganic material.
OX, ITO (InSny OX), InOX, and the like, and organic materials include polyaniline. 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. Transparent electrode layer 22
It is more preferable that a, 22b, 22c, and 22d have a high absorption coefficient with respect to the writing light 14 and have a property of converting the heat into heat. When the image recording layers 23a, 23b do not absorb the wavelength of the writing light 14, the transparent electrode layers 22a, 22b,
At 22c and 22d, heat is converted to heat, and the image recording layers 23a and 23
b.

The front support 21 needs at least the following characteristics. First, the transparent electrode layers 22a, 22b, 22
c, 22d, the image recording layers 23a and 23b, the color filter 24, the dielectric layer 25, the rear support 26, and the visible light absorbing layer 27, and the force generated by writing or erasing an image, and transport. It is necessary to have enough strength to withstand the impact of time. 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.

When writing is performed in the X1 direction, the front support 21 is located between the writing light 14 and the image recording layer 23a, and is therefore formed of a material that allows the writing light 14 to be sufficiently transmitted. Need to be In this case, for example, glass, a plastic sheet, or the like is appropriate. Alternatively, in order to enhance the transmittance of both visible light or writing light 14 and visible light, a layer having an antireflection effect or a film thickness capable of exhibiting the antireflection effect is adjusted as necessary, or both are adjusted. The antireflection property may be enhanced by combining them.

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 sufficient strength, the image recording layer 23
The transparent electrode layer 22d and the visible light absorbing layer 2a are kept uniform by the heat stress generated during writing.
It is sufficient to have a strength such that 7 is not broken. 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.

The dielectric layer 25 includes the image recording layers 23a and 23
b, the thickness of the transparent electrode layers 22b and 22c and the color filter
It is sufficient to have a strength such that 4 is not broken. Furthermore, it is necessary to efficiently transmit the writing light regardless of the irradiation direction of the writing light 14. Also, the transparent electrode layers 22b and 22c
It is important to have the property to electrically insulate.

The positions of the dielectric layer 25 and the color filter 24 may be relatively interchanged.
4 has the characteristics of the dielectric layer 25, the dielectric layer 25 becomes unnecessary.

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. 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. In addition, Bi (bismuth)-
Black materials such as 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.

As a method of forming the color filter 24, four types of methods can be used, which are broadly divided into conventionally known methods, for example, a dyeing method, a pigment dispersion method, a printing method and an electrodeposition method.

For example, the color filter 24 by the dyeing method forms a dyeable photosensitive film on the front side of the front support 21,
A dye pattern is formed by pattern exposure through a photomask in alignment with any one of the phosphor layers of R, G, and B, 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, in order to protect and flatten the pixel portion, a transparent top coat layer is provided on the surface to form a color filter 24.

In the printing method, R, R and R are obtained by using an ink in which a pigment is dispersed in a thermoplastic resin or an ultraviolet curable resin.
Each pixel is printed in alignment with the G and B color filter layers to produce a color filter 24.

Further, in the electrodeposition method, ITO is formed on the dielectric layer 25, and this is patterned by matching with any one of the R, G, and B color filter layers.
Expose the membrane. 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 three colors of R, G, and B to obtain a color filter. 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, coated on a substrate, and dried to form a colored layer. Is applied, dried, and aligned with any of the R, G, and B color filter layers using a mask, exposed, and developed to form a resist pattern. The colored layer where the resist was removed is 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 is peeled off, and the color filter is repeated. To complete.

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 photocolorable 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, benzyldimethyl ketal and the like.

If the color filter requires heat resistance, it may be formed by any of the above methods. However, the material must have heat resistance, and a heat-resistant pigment or colored glass may be used. Melting point glass frit (Pb
A paste in which O, B ₂ O ₃ , SiO _2, etc.) are dispersed 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. It is desirable that particles having a particle size of 1 μm or more account for 10% by weight or less of all particles. 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.

Examples of the heat-resistant colored glass used above include the following. There are many types of colored glass due to its colored structure, and the color changes depending on the conditions even with the same raw material. 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.
Yellow lead oxide, lead white, potassium nitrite, 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 invention, a mixture obtained by mixing, heating, abducting, and vitrifying the mixture and cooling and pulverizing the mixture is used.

Although the method of directly forming the color filter 24 on the dielectric layer 25 has been described above, the color filter 24 which is separately manufactured is attached to the dielectric layer 25 and the image display panel 20 of this embodiment is attached. It can also be.

In this embodiment, as the color filter 24, R
Although the GB filter is used, there is also an example in which two color filters of yellow (Y) -blue (B) are used to display four colors of white, yellow, blue, and black. It is also possible to use cyan (C), magenta (M), and yellow (Y) filters in place of RGB. The CMY-based filter has the advantage that the reflectance at the time of displaying white is higher than that of the RGB filter, but on the other hand, when expressing RGB, R, R
There is a problem that a white component is mixed in each of the colors G and B. It is necessary to use a filter suitable for the purpose according to the application.

Next, the operation of the image display device 10 according to the present embodiment will be described with reference to FIGS. The image recording on the image display board 20 is performed by replacing the image signal, character information, code signal, line drawing signal information, and the like with the ON / OFF of the writing light 14 or a change in intensity. Specifically, recording of digital images such as characters, codes, and line drawings is performed by controlling the writing light 14 to be turned on and off, and recording of analog images is performed by controlling the intensity change of the writing light 14. It is also possible to convert the image information into halftone information and record it.

When writing an image on the image display panel 20, first, the light output device 11 outputs the writing light 14 used for writing the image. As the writing light 14, a light having a high intensity and capable of local irradiation is suitable. Specifically, an argon laser (wavelength 514n) is used.
m, 488 nm), helium laser (wavelength 633 n)
m), semiconductor laser (wavelength 780 nm, 810 nm, 1
310 nm, 1340 nm, 1480 nm, 1550 n
m), a YAG laser (wavelength 1064 nm) and the like. Further, non-coherent light such as a light emitting diode or a halogen lamp may be condensed and used by a lens system.

The writing light 14 condensed and output from the light output device 11 in a spot shape reaches the rotating polygon mirror 12 and changes its traveling direction by being reflected there. This traveling direction can be changed by rotating the polygon mirror 12, and in the case of FIG. 2, the traveling direction of the writing light 14 after the reflection of the polygon mirror 12 can be changed up and down.

The writing light 14 whose traveling direction has been changed by the polygon mirror 12 reaches the deflector 13, and the polarizer 13 can arbitrarily change the traveling direction of the writing light 14. In the case of FIG. 2, the polarizer 13 can change the traveling direction of the writing light 14 after the output from the polarizer 13 to a direction perpendicular to the paper surface. Here, as the deflector 13,
Polygon mirror, galvanometer mirror, or acousto-optic (A
O) The effect can also be used.

The writing light 14 whose traveling direction is determined by the deflector 13 is applied to the image display plate 20. The writing light 14 can be applied to the image display plate 20 from either the X1 direction or the Y1 direction shown in FIG. 1, but in the present embodiment, the case where the writing light 14 is applied from the Y1 direction will be described.

The image recording on the image display panel 20 is performed by the first irradiation of the writing light 14 for recording only the white component of the image to be recorded and the second irradiation of the writing light 14 for recording a color other than the white component. Will be

First, the first irradiation of the writing light 14 will be described. In the first irradiation of the writing light 14, a strong DC voltage is applied between the transparent electrode layers 22c and 22d, and no voltage is applied between the transparent electrode layers 22a and 22b.

The writing light 14 applied to the image display panel 20 from the Y1 direction is applied to the visible light absorbing layer 27 and the rear support 2.
6 and the transparent electrode layer 22d, and the image recording layer 23b
Reach Writing light 14 that has reached image recording layer 23b
Then, after converting a part of the light energy into heat energy, the transparent electrode layer 22c, the dielectric layer 25,
The light passes through the color filter 24 and the transparent electrode 22b and reaches the image recording layer 23a. The writing light 14 that has reached the image recording layer 23a converts the light energy into heat energy there.

Here, since the writing light 14 having a narrow optical width such as a laser is used, the irradiation of the writing light 14 is performed locally. Therefore, the image recording layers 23a and 23b irradiated with the writing light 14 are locally heated by the heat energy generated by the irradiation.

The image recording layers 23a and 23b have the property of causing a phase transition by heating, and the transmittance and the reflection coefficient are changed by the phase transition. Image recording layer 2
3a and 23b are colorless and transparent at the initial stage, but their phase transition lowers their transmittance and at the same time improves their reflectance. In this case, the image recording layers 23a and 23b irradiated with the writing light 14 locally change the phase of the irradiated portions.

After the end of the irradiation of the writing light 14, the irradiated portions of the image recording layers 23a and 23b maintain the state after the phase transition. As described above, the image recording layer 23a irradiated with the writing light 14 retains the phase after the phase transition even after the irradiation is completed. Therefore, the portion of the image recording layer 23a irradiated with the writing light 14 becomes white due to the phase transition in which the transmittance is reduced and the reflectance is simultaneously increased. By sequentially performing such irradiation, an image of a white portion is recorded on the image recording layer 23a. After the irradiation of the writing light 14 is completed, the phase of the image recording layer 23b may be returned to the initial state by applying a voltage. However, from the viewpoint of power saving, it is preferable to keep the state of the image recording layer 23b as it is.

Next, the second irradiation of the writing light 14 will be described. In the second irradiation of the writing light 14, a strong DC voltage is applied between the transparent electrode layers 22a and 22b, and no voltage is applied between the transparent electrode layers 22c and 22d.

The writing light 14 applied to the image display panel 20 in the Y1 direction locally heats the image recording layers 23a and 23b in the same manner as in the first irradiation of the writing light 14. Since the second irradiation is for recording a color other than white, the second irradiation is not performed on the phase transition portion of the image recording layer 23a that has undergone the phase transition by the first irradiation.

By the second irradiation, the image recording layer 23
The portions irradiated with the writing light 14a and 23b locally undergo phase transition. Even after the irradiation of the writing light 14 is completed, the irradiated portions of the transparent electrode layers 22a and 22b maintain the state after the phase transition, but the image recording layer 23a has the transparent electrode layer 22a.
A strong DC voltage is applied by a and 22b, and the phase of the irradiated portion of the image recording layer 23a is returned to the initial state by applying this strong DC electric field while holding the heat by irradiation. Here, since the second irradiation is not performed on the irradiated portion of the image recording layer 23a colored white by the first irradiation, the colored portion of the image recording layer 23a colored white by the first irradiation Is not returned to the initial state.

As described above, the image recording layer 23b irradiated with the writing light 14 retains the phase after the phase transition even after the end of the irradiation, while the image recording layer 23a retains the phase after the first irradiation. Will be maintained.

Such irradiation is sequentially performed, and an image is recorded on the image recording layer 23b. Next, the principle of color display of the image display panel 20 on which an image is recorded in this manner will be described.

The image display panel 2 on which the image is recorded as described above
When visible light is incident on X0 from the X1 direction, the visible light is transmitted, reflected, and absorbed according to the state in the image display panel 20, thereby reproducing a color.

First, the principle of reproducing white color will be described. When there is a phase transition portion in the image recording layer 23a, X1
Light incident from the direction is reflected at the phase transition portion of the image recording layer 23a, and the reflected light passes through the transparent electrode layer 22a and the front support 21 and can be observed from the visible light incident side. Since this reflected light contains all the color components of the visible light incident from X1, the reflected light observable from the visible light incident side is white. Thereby, the white component of the image is reproduced.

Next, the principle of reproducing black will be described. Visible light incident on the image recording layer 23a other than at the phase transition point passes through the image recording layer 23a and is transmitted to the image recording layer 23b.
Reach When the visible light that has reached the image recording layer 23b is incident on a portion other than the phase transition portion of the image recording layer 23b, the visible light also passes through the image recording layer 23b and reaches the visible light absorbing layer 27. Since the visible light that has reached the visible light absorbing layer 27 is absorbed by the visible light absorbing layer 27, the visible light that has reached the visible light absorbing layer 27 is not observed from the visible light incident side of the image display panel 20. . Therefore, when such a portion is viewed from the X1 direction, the position is observed as black, thereby reproducing the black component of the image.

Next, the manner in which colors other than white and black are reproduced will be described. Visible light incident on the image recording layer 23a other than at the phase transition point passes through the image recording layer 23a, passes through the color filter 24, and reaches the image recording layer 23b. For example, when focusing on the blue (B1) filter,
The visible light that has reached the B1 filter of the color filter 24 passes through the B1 filter and reaches the image recording layer 23b. When visible light passes through the B1 filter, the B1 filter of the color filter 24 absorbs light other than blue light and transmits only blue light to the image recording layer 23b. B
The visible light transmitted through one filter reaches the image recording layer 23b, and when there is a phase transition portion in the image recording layer 23b,
The light is reflected at the phase transition portion, passes through the color filter 24 again, and reaches the visible light incident side of the image display panel 20. At this time, the visible light incident from the X1 direction passes through the red (R1) filter or the green (G1) filter, is reflected at the phase transition portion of the image recording layer 23b, and the reflected light may enter the B1 filter. However, since all such reflected light is absorbed by the B filter, it does not reach the visible light incident side of the image display panel 20.

When the reflected light reaching the visible light incident side of the image display panel 20 is viewed from the X1 side, the position of the reflected light is observed to be blue, thereby reproducing the blue component of the image. Becomes Similarly, a red component and a green component are reproduced, and thereby, color components other than white and black are reproduced.

Then, as described above, white, black, blue,
When the image display plate 20 on which red and green are reproduced is viewed from the X1 direction, it can be observed as a color image display.

The image recorded on the image recording layer 23a can be erased by applying an AC voltage between the transparent electrode layers 22a and 22b, and the image recorded on the image recording layer 23b can be erased by the transparent electrode layers 22c and 22b. Erasing can be performed by applying an AC voltage between 22d. The pattern of the applied voltage includes a sine wave, a triangular wave, a pulse wave, and 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.

As described above, in this embodiment, the image recording layer 23a for recording a white component, the transparent electrodes 22a and 22b for applying a voltage to the image recording layer 23a, the color filter 24 for producing red, blue, and yellow, The image display plate 20 is formed by the image recording layer 23b for recording other than the black component, the transparent electrodes 22c and 22d for applying a voltage to the image recording layer 23b, and the visible light absorbing layer 27 for absorbing visible light. The image is recorded by irradiating the writing light 14 which is irradiated from the light output device 11 and the direction of which is determined by the polygon mirror 12 and the polarizer 13 twice, so that white is directly reflected from the image recording layer 23a. It is possible to reproduce white light having a high reflectivity.

In this embodiment, the writing light 14 is scanned by the polygon mirror 12 and the polarizer 13. However, the image display plate 20 itself is slid by a slide mechanism (not shown) to thereby relatively write. The light 14 may be scanned.

The polygon mirror 12 and the deflector 1
3 and the slide mechanism may be combined. Further, the light output device 11 may be arbitrarily slid in the two-dimensional direction to scan the writing light 14.

In this embodiment, the first writing light 1
4, writing to the image recording layer 23 a was performed, and writing was performed to the image recording layer 23 b when irradiating the writing light 14 for the second time. Writing to the layer 23b may be performed, and writing to the image recording layer 23a may be performed at the time of the second irradiation.

Next, the image display panel 30 of the second embodiment
Will be described. FIG. 3 is a cross-sectional view illustrating a configuration of the image display panel 30 according to the second embodiment. Image display board 30
Indicates a front support 21, a writing light blocking layer 31, a transparent electrode layer 22a, an image recording layer 23a, a transparent electrode layer 22b, and a color filter
4, dielectric layer 25, transparent electrode layer 22c, image recording layer 23
b, the transparent electrode layer 22d, the rear support 26, and the visible light absorbing layer 27 are arranged. The image display panel 30 of the present embodiment has the same configuration as that of the first embodiment except that the writing light blocking layer 31 is inserted.

The write light blocking layer 31 is formed by the write light 14
It is necessary to have a function of reflecting or absorbing light, or both functions. At the same time, the write light blocking layer 31 needs to have high transmittance in all visible light wavelength regions. Plastic materials exhibiting such properties include anthraquinone derivatives, phthalocyanine derivatives, naphthalocyanine-based compounds, cobalt complexes, dithiol-based metal complexes, squarium compounds, immonium-based compounds,
There is a plastic film containing an acetylene derivative or the like.

The components and operations other than the write-light blocking layer 31 are the same as those in the first embodiment, and a description thereof will be omitted. Next, the role of the write light blocking layer 31 which is different from the first embodiment will be described.

The writing light 14 incident from the Y1 direction passes through the image recording layer 23b and reaches the image recording layer 23a.
A part of the writing light 14 that has reached the image recording layer 23a is converted into thermal energy in the image recording layer 23a, but a part of the writing light 14 is transmitted through the image recording layer 23a.

The writing light 14 transmitted through the image recording layer 23a is absorbed or reflected by the writing light blocking layer 31. As described above, in the present embodiment, since the writing light blocking layer 31 is inserted, the writing light 14 transmitted through the image recording layer 23a is transmitted through the front support 21 and emitted from the display surface of the image display panel 20. Can be prevented.

By selecting a writing light blocking layer 31 having a high reflectance with respect to the writing light 14, the writing light 1 transmitted through the image recording layer 23a is selected.
4 can be reflected by the writing light blocking layer 31, and the image recording layers 23a and 23b can be irradiated again with the reflected writing light 14, so that the writing efficiency can be improved.

Further, effects similar to those of the first embodiment can be obtained. Next, an image display panel 40 according to a third embodiment will be described. FIG. 4 is a cross-sectional view illustrating a configuration of the image display panel 40 according to the third embodiment.

The image display panel 40 is provided in a direction X in which a human looks straight.
1, the front support 21, the transparent electrode layer 22a,
Image recording layer 23a, transparent electrode layer 22b, color filter 24, dielectric layer 25, transparent electrode layer 22c, image recording layer 2
3b, the transparent electrode layer 22d, the rear support 26, and the visible light absorbing layer 27.
Here, an RGB filter is used as the color filter 24, and a red filter portion R1, a green filter portion G1, and a blue filter portion B1 are formed for each pixel. Each filter for each pixel is filled with a black matrix Bk, which is a light shielding portion.

The method for forming the black matrix Bk may be any of the conventionally known methods, 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 Bk made of a metal film such as chromium is formed by forming a metal film on any surface of the front supporting substrate by a method such as vapor deposition, and then performing a photolithography method using a photoresist and an etching process. To form

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 support substrates 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 Bk is formed by using a light-shielding photosensitive material in which pigments of a plurality of hues are combined. Is also possible. Further, Japanese Unexamined Patent Application Publication Nos. Hei.
No. 62, a mixture of a plurality of organic pigments and carbon black, or a mixture of a plurality of organic pigments and an organic black pigment, a black matrix B made of a light-shielding material.
k can be formed.

The components and operations other than the black matrix Bk are the same as in the first embodiment, and a description thereof will not be repeated. By providing the black matrix Bk, 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.

Further, the same effect as in the first embodiment can be obtained. Next, an image display panel 50 according to a fourth embodiment will be described. FIG. 5 shows an image display panel 5 according to the fourth embodiment.
FIG. 2 is a cross-sectional view showing a configuration of a zero.

The image display panel 50 is provided in a direction X in which a human looks directly.
1, in order from the side of visible light absorbing front support 51, transparent electrode layer 22a, image recording layer 23a, transparent electrode layer 22b, color filter 24, dielectric layer 25, transparent electrode layer 22c,
The image recording layer 23b, the transparent electrode layer 22d, and the visible light absorbing rear support 52 are arranged.

This embodiment is different from the second embodiment in that the front support 21 and the writing light blocking layer 3 of the image display panel 30 are provided.
1 is replaced by a visible light absorbing front support 51, and the rear support 26 and the visible light absorbing layer 27 are replaced by a visible light absorbing rear support 52. The visible light absorbing front support 51 is And writing light blocking layer 3
1, having both properties, the visible light absorbing rear support 52
It has the characteristics of both the rear support 26 and the visible light absorbing layer 27.

The other points are the same as in the second embodiment, and the description is omitted. Next, a screen display device 60 according to the fifth embodiment will be described. FIG. 6 is a schematic configuration diagram of the screen display device 60 in the present embodiment.

The screen display device 60 of this embodiment is provided with a movable mirror 61 instead of the polarizer 13 of the image display device 10 of the first embodiment shown in FIG.
The writing light 14 is made to scan by sliding. The other points are the same as those of the first embodiment, and the description is omitted.

[0106]

Next, an example of the image display panel 50 according to the fourth embodiment shown in FIG. 5 will be described.

As the material of the visible light absorbing front support 51, a 40 mm square infrared absorbing glass was used. On this surface, a transparent electrode layer 22a made of ITO having a thickness of 180 nm was formed by a sputtering method.

Next, the dielectric layer 25 of 30 μm thick Si
A photopolymerizable monomer and a photosensitive agent were added to a coloring composition comprising a pigment and its vehicle on an O ₂ plate, and the impression and exposure were repeated as a photosensitive coloring composition to produce a color filter 24. On this surface and on the side opposite to the color filter 24, transparent electrode layers 22b and 22c made of ITO with a thickness of 180 nm were formed by a sputtering method.

Next, the surface of the transparent electrode layer 22a has a diameter of 1 mm.
After applying 8 mm glass beads to form a spacer, a curable epoxy resin was applied to the periphery of the transparent electrode layer 22a for 10 hours and bonded to the transparent electrode layer 22b. At this time, when viewed perpendicularly from the side of the visible light absorbing front support 51, two places facing each other were formed at a position where no epoxy resin was present by about 10 mm, and this was used as a liquid crystal injection port. When the epoxy resin is cured, the image recording layer 23 is hardened.
a visible light absorbing front support 5 so that the distance between
1 and the dielectric layer 25 were adhered by applying sufficient pressure. However, sufficient care was taken not to destroy the dielectric layer 25 and the color filter 24.

Next, as a material of the visible light absorbing rear support 52 of the image display panel 50, a 40 mm square infrared transmitting glass was used. A film thickness of 180 is formed on this surface by sputtering.
A transparent electrode layer 22d made of ITO having a thickness of nm was formed.

Next, the surface of the transparent electrode layer 22d has a diameter of 1 mm.
After 8 mm glass beads were applied to form spacers, a curing type epoxy resin was applied to the periphery of the transparent electrode layer 22d for 10 hours and bonded to the transparent electrode layer 22c. At this time, when viewed perpendicularly from the side of the visible light absorbing front support 51, two places facing each other were formed at a position where no epoxy resin was present by about 10 mm, and this was used as a liquid crystal injection port. When the epoxy resin is cured, the image recording layer 23 is hardened.
visible light absorbing rear support 5 so that the distance between
2 and the dielectric layer 25 were adhered by applying sufficient pressure.
However, sufficient care was taken not to destroy the dielectric layer 25 and the color filter 24.

Furthermore, 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 the resultant was allowed to cool to room temperature while applying the voltage, and the image recording layers 23 a and 23 b were transparent. In this state, the image display panel 50 was completed.

Next, the completed image display panel 50 was set in the image display apparatus 10 of FIG. 2 in place of the image display panel 20 so that the writing light 14 was irradiated from the visible light absorbing rear support 52 side. . Here, a laser diode having a wavelength of 1480 nm and an output of 100 mW was used for the optical output device 11. Then, the writing light 14 output from the light output device 11 was deflected by the polygon mirror 12 and the polarizer 13 and made to enter the visible light absorbing rear support 52 of the image display panel 50 almost perpendicularly.

The incident writing light 14 is applied to the image recording layer 2.
3a, 23b and transparent electrode layers 22a, 22b, 22c, 2
2d, whereby the image recording layers 23a, 23b
Was phase-transformed and became cloudy. As a result, a white display section was formed. Further, while a 70 V DC voltage is applied to the transparent electrode layers 22a and 22b, the writing light
Irradiates the image recording layer 23b to which no voltage is applied.
A phase transition occurred only by the above method, and a clear color image having a high resolution of 300 dpi could be displayed.

Thereafter, the image was erased by applying an alternating voltage of 250 Hz and 40 V for 1 second, and the image was restored. In this way, a high-resolution, high-contrast, rewritable, reflective color display having a memory function of image information was realized.

Further, the image display panel 50 formed by the above method is connected to the image display panel 2 of the screen display device 60 shown in FIG.
Instead of 0, it was set so that writing light was irradiated from the visible light absorbing rear support 52 side. Here, a laser diode having a wavelength of 1480 nm and an output of 100 mW was used for the optical output device 11. Then, the writing light 14 output from the light output device 11 was deflected in the left and right directions by the polygon mirror 12 and was deflected in the up and down directions by the mirror 61 and was irradiated on the image display plate 50. At this time, the mirror 61 was moved at a constant speed, and the speed was set so that the polygon mirror 12 shifted by one pixel in the vertical direction when drawing the next line.

The incident writing light 14 is applied to the image recording layer 2.
3a, 23b and transparent electrode layers 22a, 22b, 22c, 2
2d, whereby the image recording layers 23a, 23b
Was phase-transformed and became cloudy. As a result, a white display section was formed. Further, while a 70 V DC voltage is applied to the transparent electrode layers 22a and 22b, the writing light
Irradiates the image recording layer 23b to which no voltage is applied.
A phase transition occurred only by the above method, and a clear color image having a high resolution of 300 dpi could be displayed.

Thereafter, the image was erased by applying an alternating voltage of 250 Hz and 40 V for 1 second, and the image was restored. In this way, a high-resolution, high-contrast, rewritable, reflective color display having a memory function of image information was realized.

[0119]

As described above, according to the present invention, the first
Image recording having a visible light absorbing layer for absorbing visible light transmitted through the first image recording layer and the second image recording layer by disposing a color filter between the image recording layer and the second image recording layer Since the plate is used, the white color can be reproduced by the light directly reflected from the first image recording layer, so that it is possible to reproduce a white color having a high reflectance.

Further, in the present invention, a color filter is arranged between the first image recording layer and the second image recording layer,
The image recording layer has a visible light absorbing layer that absorbs visible light transmitted through the image recording layer and the second image recording layer, and a screen display device that has an image recording unit that records an image thereon. Can be reproduced by the light directly reflected from the image recording layer, whereby white with high reflectance can be reproduced.

[Brief description of the drawings]

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

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

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

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

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

FIG. 6 is a schematic configuration diagram of a screen display device according to a fifth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 image display device 11 light output device 12 polygon mirror 13 deflector 14 writing light 20 image display plate 22a transparent electrode layer 22b transparent electrode layer 22c transparent electrode layer 22d transparent electrode layer 23a image recording layer 23b image recording layer 24 color filter 27 visible Light absorbing layer

Claims (6)

[Claims] 1. An image display plate having a function of maintaining a display state of image information, comprising a pair of upper and lower transparent electrodes, wherein a phase transition accompanied by a change in transmittance and reflectance is caused by heating. A first image recording layer for recording the image information by maintaining the state, and a pair of upper and lower transparent electrodes, wherein a phase transition accompanied by a change in transmittance and reflectance is caused by heating, and the phase transition state A second image recording layer that records the image information by holding the first image recording layer; a color filter that is positioned between the first image recording layer and the second image recording layer; And a visible light absorbing layer that absorbs visible light transmitted through the second image recording layer. 2. The first image recording layer maintains a state after a phase transition when heated in a state where no voltage is applied by the transparent electrodes located above and below the first image recording layer. The second image recording layer may maintain a state after the phase transition when heated in a state where no voltage is applied by the transparent electrodes located above and below the second image recording layer. The image display panel according to claim 1, wherein: 3. An image display device having a function of maintaining a display state of image information, comprising: a pair of upper and lower transparent electrodes, wherein a phase transition accompanied by a change in transmittance and reflectance is caused by heating; A first image recording layer for recording the image information by maintaining the state, and a pair of upper and lower transparent electrodes, wherein a phase transition accompanied by a change in transmittance and reflectance is caused by heating, and The second for recording the image information by holding
An image recording layer; a color filter positioned between the first image recording layer and the second image recording layer;
An image display plate having a visible light absorbing layer that absorbs visible light transmitted through the image recording layer and the second image recording layer, and the first image recording layer and the second image recording layer An image display device comprising: image recording means for recording image information. 4. The image display device according to claim 3, wherein said image recording means irradiates the first image recording layer and the second image recording layer with writing light twice. 5. A voltage is applied to the first image recording layer by the transparent electrode of the first image recording layer when an image is recorded on the second image recording layer. The image display device according to claim 3. 6. A white color is recorded by irradiating the writing light to cause a phase transition of the first image recording layer,
4. A color other than white is recorded by irradiating writing light while applying a voltage to the first image recording layer to cause a phase transition of only the second image recording layer. Image recording device.