JPH022520A - Display medium, its method and device - Google Patents

Abstract

PURPOSE:To display a high-definition color image sharply by constituting respective display layers so that temperature ranges from the glass dislocation of a high polymer liquid crystal compound to the phase shift temperature are not superimposed. CONSTITUTION:The display medium A is formed by providing a light absorbing layer 2 on a substrate 1, forming a 1st orienting layer H1 and a 1st display layer D1 - an (n)th orienting layer Hn and an (n)th display layer Dn, and an (n+1)th orienting layer Hn+1 on the light absorbing layer 2 in order, and laminating a surface protection layer 3 on the (n+1)th orienting layer Hn+1. Respective high polymer liquid crystal compounds which constitute the 1st - (n)th display layers differ in glass dislocation temperature and phase shift temperature and have the temperature ranges from the glass dislocation temperature to the phase shift temperature of the liquid crystal compounds without superimposing them. Therefore, the optical density of each display layer can be controlled independently by the display layers by modulating the temperature of the high polymer liquid crystal compounds. Consequently, the high-definition color image is displayed sharply.

Description

[Detailed description of the invention] “Industrial Application Fields” The present invention applies to floppy disks and optical disks.

Regarding display media, display methods, and devices that output and display images in response to image signals output from magneto-optical memory media, computers, etc., facsimile signals, and other image signals, especially for outputting diversified color images. The present invention relates to display media, display methods, and devices thereof.

[Prior Art] Traditionally, video output from televisions and VTRs and output from interactions with computers have been output and displayed on CRT (Flaun tube) and TN (Twisted Nematic) liquid crystal display monitors, and WP (Word Processor) A high-definition image of a document 1 graphic, etc., produced by a computer or facsimile has been output and displayed on paper as a printed hard copy.

However, the CRT has the disadvantage that it outputs a beautiful image when outputting a moving image, but when an image remains still for a long period of time, flicker and scanning lines due to insufficient resolution reduce visibility.

In addition, in conventional liquid crystal displays such as the above-mentioned TN liquid crystal, is it possible to make the device thinner? It is difficult to manufacture the device by sandwiching the liquid crystal between a pair of glass substrates, and the screen is dark. There were some problems.

Furthermore, since CRT and TN liquid crystals do not have stable image memory even while outputting still images as described in 2 above,
There are drawbacks such as the need to constantly access the beam and pixels.

In contrast, the images output to vapor are high-definition,
In addition, if a large number of images are used, it will take up space to organize them, and if a large number of them are discarded, resources will be wasted.

On the other hand, attempts have been made to use polymer liquid crystal as a display medium for outputting and displaying color images. For example, JP-A-52-
Recording media using cholesteric polymer liquid crystals have been proposed, such as in Japanese Patent Laid-Open No. 154340 and Japanese Patent Laid-Open No. 62-66990. However, the above proposal targets light of a specific wavelength and cannot provide sufficient performance as a display medium.

Also, as a display medium, JP-A-62-14114, JP-A-62-278530, JP-A-52-27
Display media reported in Japanese Patent No. 8529 and the like are known, but they are not sufficient for the purpose of displaying color images.

On the other hand, it has been proposed to add a dichroic dye to color the polymer liquid crystal itself, or to use a polymer liquid crystal copolymerized with dye residues as shown in Japanese Patent Application Laid-open No. 175205/1985. , one with sufficient contrast and good one-color linearity has not been obtained.

On the other hand, it has also been proposed that polymer liquid crystals or low-molecular cholesteric liquid crystals be arranged in Brehner alignment and the hue can be changed by an electric field. [Molecula Crystal Refit Crystal J (T, by Uchida, Shishito, and Wada)
Uchida, C.5hishido and M.W.
ada rMol, Cyst, Liq,
Cyst, J 39, p. 127 (1,977)
] However, this method is difficult to display large-area, high-definition color images because the hue can only be changed by applying an electric field, and there is no usable holding mechanism, and the definition is determined by the electrodes that can be driven. Met.

[Problem to be solved by the invention] The present invention has been made in view of the current situation, and
The purpose of the present invention is to provide a display medium, a method for displaying the same, and a display device that can express high-definition color images, which have conventionally been obtained only as hard copies, with the same sharpness as hard copies, and that can repeatedly display and erase color images. It is something to do.

[Means for Solving the Problem] and [Operation] That is, the present invention provides a display medium comprising 1:1 display layer of polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures, The present invention is a display medium characterized in that the temperature ranges from the glass transition temperature to the phase transition temperature of the polymeric liquid crystal compounds in each display layer do not overlap.

In addition, 1 the present invention is formed by laminating polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures as display layers, and in which the liquid crystalline polymeric compounds of each display layer have a temperature ranging from the glass transition temperature to the phase transition temperature. A display method characterized in that the optical density of each display layer is independently controlled for each display layer by modulating the temperature of the polymeric liquid crystal compound in a display medium whose temperature ranges do not overlap, and It has two or more heating means in the direction of sequentially performing recording and erasing on the display medium, and the heating means sequentially selects each pixel of the display layer and modulates the temperature of the polymeric liquid crystal compound. This display method is characterized in that the optical density of each display layer is independently controlled.

Furthermore, the present invention has a structure in which polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures are laminated as a display layer, and in which the liquid crystalline polymeric compounds of each display layer have a temperature ranging from the glass transition temperature to the phase transition temperature. a display medium having a temperature range that does not overlap, a means for sequentially selecting display pixels of a display layer of the display medium, and a heating means having two or more heating element heads in a direction for sequentially recording and erasing information on the display medium. A display device comprising a display layer of polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures, wherein the glass transition temperature of the polymeric liquid crystalline compound of each display layer is to a phase transition temperature, and a control means for controlling the optical density of each display layer independently for each display layer by modulating the temperature of the polymeric liquid crystal compound. This is a display device characterized by:

The present invention will be explained in detail below.

FIG. 1 is an explanatory diagram showing an example of a display medium of the present invention.

In the figure, the display medium A of the present invention includes a light absorption layer 2 provided on a substrate 1, and a first alignment layer 11 on the light absorption layer 2.
and the first display layer DI, the second alignment layer 112 and the second display layer D2. ......, the n-th alignment layer Hn, the 0th display layer Dn, and the n+1-th alignment layer 11n+1 are sequentially provided, and the surface protection layer 3 is laminated on the 1st opening ÷l alignment layer Hn+1. Each of the polymeric liquid crystalline compounds constituting each of the first to nth display layers has a different glass transition temperature and a phase transition point Iff, and the phase change temperature is different from the glass transition temperature of the polymeric liquid crystalline compound of each display layer. The temperature ranges up to the transition temperature are constructed so that they do not overlap with each other.

The polymeric liquid crystalline compounds that can be used in the present invention include thermotropic main chain type/side chain type polymeric liquid crystalline compounds, which have a nematic phase.

It contains a smectic phase, a chiral nematic phase, and a chiral smectic phase, and its temperature range is from 0°C to 30°C.
0°C is preferred. If it is less than 0°C, it is difficult to control the temperature, and if it exceeds 300°C, the display energy becomes large, which is not preferable. Furthermore, it has a glass transition point,
Since the liquid crystal structure can be fixed without any holding operation, it is important for display with memory properties.

As the polymeric liquid crystalline compound having a chiral nematic phase or chiral smectic phase used in the present invention, a side chain type polymeric liquid crystalline compound, a main chain type polymeric liquid crystalline compound, etc. can be used. Examples of the side chain type polymeric liquid crystalline compounds include those shown in the following formulas (1) to (12).

(However, in the formula, * indicates an asymmetric carbon center and is 5 to 1000) (m2 = 2 to 15) (7) I+ -fCl+2-C→- (o+, = 2 to 10) +C]1□- C→− CI! -(-(:H The liquid crystal compound is composed of a meso-kene group, a flexible chain, and an optically active group, and is polymerized with an ester bond, an amide bond, a peptide bond, a urethane bond, an ether bond, etc. More preferably, an ester bond is used. or used.

Specific compounds that can be used as mesogen groups include terphenyldicarboxylic acid, P-terephthalic acid,
Naphthalenedicarboxylic acid, biphenyldicarboxylic acid, stilbenzenedicarboxylic acid, azobenzenedicarboxylic acid, azoxybenzenedicarboxylic acid, cyclohexanedicarboxylic acid, biphenyletherdicarboxylic acid, biphenoxyethanedicarboxylic acid, biphenylethanedicarboxylic acid.

Dicarboxylic acids such as carboxycinnamic acid, hydroquinone, cyhydroxybiphenyl, cyhydroxyterphenyl, cyhydroxyazobenzene, cyhydroxyazoxybenzene, cyhydroxycymethylazobenzene, cyhydroxymethylazoxyhenzene , dihyde-xypyridacin, cyhydro-xynaphthalene, dihydroxyphenyl ether, bis(hydroxyphenoxy)ethane, and other diols; hydroxybenzoic acid, hydroxybiphenylcarboxylic acid, hydroxyterphenylcarboxylic acid, hydroxycinnamic acid, and hydroxyazobenzenecarboxylic acid.

Pitroxycarboxylic acids such as hydroxyazoxybenzenecarboxylic acid and hydroxystilbenecarboxylic acid can be used.

Raw materials for flexible chains include methylene glycol,
Ethylene glycol, propanediol, butanediol, bentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, dodecanediol, tridecanediol, tetradecanediol, pentadecanediol, diethylene glycol, triethylene glycol, tetra Diols such as ethylene glycol, nonaethylene glycol, and tridecaethylene glycol, and dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superric acid, azelaic acid, and sebacic acid can be used.

The optically active group is preferably bifunctional. Specifically, (+)-3-methyl-1,6-hexanediol (-)
-3-methyl-1,6-hexanediol (+)-3-
Methylazivic acid (-)-3-Methylazivic acid (D)-72l--(L)-mannitol (1-IIlanni to
e) (+)-Pantothenic acid (+) -1,2,-4-)-rehydroxy 3.3
-dimethylphthane (-) -1,2-propanediol (+) -1,2-propanediol (+) -lactic acid (-) -lactic acid (2S, 5S) -2-methyl-1,5-diol 3-oxa Hexane (2S, 53.83)-2,5-dimethyl-3,6-
Mesogenic groups, flexible chains such as thioxanonan-1,8-diol and above.

By polycondensing an optically active group, the liquid crystalline polymer compound having an asymmetric carbon of the present invention can be obtained. At this time, it is preferable to use a catalyst to improve the degree of polymerization and reduce impurities due to side reactions, etc. by circulation, or to remove them by a reprecipitation method or the like after completion of polycondensation.

Specifically, compounds represented by the following formulas (13) to (25) can be mentioned. The polymer referred to in the present invention refers to a main chain type having n2 or 5 or more, as shown below. (Hereinafter, n2=5-1000) (death=2-15
．． x+y=1) (x+y=1.m,=2~l5) (x+y It:1=-CIl, CI!→C1+,→-R4-(C
1l□← (x + y -1, -2 = 2 to 15) (x + y = 1
．． Death=2~15) (Recommendation=1~5) (@4=1~3 F=1~20) (ms=o~5) 0~5) (ms=o~5) (+15 0~5) Furthermore, the polymeric liquid crystalline compounds having a nematic phase and smectic phase used in the present invention include side chain type polymeric liquid crystalline compounds and main chain type polymeric liquid crystalline compounds.

Since these do not have an optically active group, they do not exhibit a helical structure, but they can be effectively used in combination with the liquid crystalline polymer compound having the optically active group.

Specifically, those shown in the following formulas (26) to (34) may be mentioned.

→C-Cl+, →- R = C, 11, □.

n=1-12 m=1. n=2 CIIi m=1~12 Tg=40℃, Tc1)=90"CCI+3 →C1l□-C← R=C,II□5oI n=1~I2 m=1゜n=2 m=1~12 Tg = 110°C, Tc1) = 140°C R = Cyo11
□□, 0- n=1~12 m=1. n=1 m=1~12 Tg=150℃, Tcj)=240'Cn=1~1
2 n=2゜-+(:Il□-C→-r:0 Tg=20℃, TcJ=151'Cx+y=1.
Orr+= l”+2 x=o, I, y=0.9, m=2 Tg
=11νC, TcJ=184℃n=1~12 n=6゜Tg=55℃, Tcf=100℃ R+ 2C-11t-,+0- R2=Czllt1++0- n=1-12 m=ρ=l, n = 11 m depth ~ 12 ff = 1 ~ 12 Tg = 39°C, TcI! =74℃ x=1~12 n=1~12R=CH
Knee, C1hO, CR~, H-2x=3. n-3,R
=l! -, Tg = 5°C, Tci' = 114°C n = 1
~8 n=8°TcI! =220°C In the present invention, a polymer liquid crystal composition comprising the above polymer liquid crystal compound and a low molecular liquid crystal compound can be used, but in order to obtain the polymer liquid crystal composition, it is necessary to It can be obtained by mixing a compound and a low-molecular liquid crystalline compound in a predetermined ratio and dissolving the mixture by heating or dissolving it in a common solvent.

Next, the low-molecular liquid crystal compound may be one that is compatible with the high-molecular liquid crystal compound, or more preferably one having an asymmetric carbon center. Specifically, chiral low-molecular liquid crystal compounds as shown in the following formulas (35) to (49) may be mentioned, but the compound is not limited thereto.

P-decyloxybenzylidene-P'-amino-2-methylbutylcinnamate (DOBAMBC) P-tetradecyloxybenzylidene-P'-amino-2-methylbutyl-α-cyanocinnamate (TDOBAMBC) P
-hexyloxybenzylidene-P'-amino-2-chloropropylcinnamate (IIOBACPC) P-octyloxybenzylidene-P'-amino-2-methylbutyl-α-chlorocinnamate (OOBAMR (:C
) P-decyloxybenzylidene-P'-amino-2-methylbutyl-α-cyanocinnamate (DOBAMBC
C) P-octyloxybenzylidene-P'-amino-
2-Methylbutyl-α-methylcinnamate (2-methylbutyl) ester 4-hexyloxyphenyl-4-(2″-methylbutyl)biphenyl-4′-carboxylate 4′-octylaniline (MBRA 4-octyloxyphenyl- 4-(2'-Methylbutyl)biphenyl-4'-carboxylateoxybiphenyl-4-carboxylate 4-hexyloxyphenyl-4-(2'-methylbutyl)biphenyl-4'-carboxylate 91.5℃ g3℃ 112 ℃
131 "C-> → →
→Crystal S＋＊C”
SaA Cholesteri Nku phase Toyoshi phase ←−−←
-←-←- In addition to 4-(2″-methylbutyl)phenyl-4-(4″-methylhexyl)biphenyl-4′-carboxylate, various polymeric liquid crystal compounds can be used or recycled. For example, discotic polymer liquid crystals or thermotropic liquid crystalline glutamic acid ester copolymers can also be used.

In a polymer liquid crystal composition formed by blending a polymer liquid crystal compound and a low molecular liquid crystal compound as shown above, the content of the polymer liquid crystal compound is 50% by weight or more, preferably 70% by weight or more.
It is desirable that the amount is at least % by weight. If it is less than 50% by weight, the helical structure cannot be sufficiently fixed.

In addition, in order to display a color image, the polymer liquid crystal composition can also provide good display by adding a dichroic dye and using its dichroism.

Furthermore, when the heating means is laser light, it is effective to add a light absorber depending on the wavelength of the laser light.

The polymer liquid crystal compound obtained as described above and the polymer liquid crystal group I & compound obtained from the polymer liquid crystal compound are as follows:
It may be used alone in the form of a film, or it may be laminated on a supporting substrate (hereinafter referred to as a substrate).

In the present invention, as the substrate that can be used, any material such as glass, plastic, or metal can be used, and if necessary, ITO115 can be used on these substrates.
A transparent electrode or a patterned electrode may be formed and used.

In addition, methods for coating or forming a thin film on the substrate include heating and melting it, or dissolving it in a solvent to make it into a liquid state, a spin code method, a casting method, a derubbing method, a bar code method, a roll coating method, This can be done by gravure coating method, doctor blade method, etc.

In order to use a liquid crystalline polymer compound having a helical structure with different periods, applying it in a mosaic or stripe pattern, it is suitable to use a screen printing method or the like, or patterning using a photoresist.

In the present invention, a display medium can be obtained by repeating the above steps and laminating two or more polymeric liquid crystalline compounds having different glass transition points and phase transition temperatures as display layers.

In this case, between the display layers made of polymeric liquid crystalline compounds,
An alignment layer, an electrode, a heat insulating layer, a light absorption layer, etc. may be provided.

In the display medium of the present invention, when the liquid crystalline polymer compound has a chiral nematic phase, it is desirable to perform horizontal alignment treatment.

Horizontal orientation treatments include stretching by mechanical force, roll stretching, shear link, electric field/magnetic field, and interface control. When using a substrate, horizontal alignment treatment using interface control is particularly preferred.

More specific horizontal alignment treatments based on interface control include the following.

■Rubbing method By solution coating, vapor deposition, sputtering, etc., on the substrate, for example, silicon oxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron nitride. Inorganic insulating materials such as polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyparaxylerin, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, polystyrene, cellulose resin, melamine resin, area resin and acrylic resin. It is also possible to provide an alignment control film formed using an organic insulating material such as .

This orientation control film is formed by forming a film of an inorganic insulating material or an organic insulating material as described above, and then rubbing the surface of the film in one direction with velvet, cloth, or paper.

■Oblique evaporation method Oxide such as SiO or fluoride or Au, AI!
Metals such as metals and their oxides are deposited from an oblique angle on the substrate.

∎Oblique etching method ③ The organic or inorganic insulating film shown in ③ is etched by irradiating it with an ion beam or oxygen plasma from an oblique direction.

(2) Use of stretched polymer membrane Membranes obtained by stretching polymer membranes such as polyester or polyvinyl alcohol also exhibit good orientation.

■ Grate ink method N can also be formed by forming grooves on the substrate surface using photolithography, stamper, or injection.
The liquid crystal is aligned in the direction of the groove.

Further, in the display medium of the present invention, when the liquid crystalline polymer compound has a chiral smectic phase, it is desirable to perform a vertical alignment treatment.

Vertical alignment treatments include stretching by mechanical force, roll stretching, shearing, electric field/magnetic field,
There are some methods based on interface control. When using a substrate,
Vertical alignment treatment using interface control is particularly preferred.

More specific vertical alignment treatments based on interface control include the following.

■ Form a vertical alignment film.

A vertically aligned layer of organic silane, lecithin, PTFE, or the like is formed on the surface of the substrate.

(2) Oblique Vapor Deposition Vertical alignment can be provided by appropriately selecting the deposition angle while rotating the substrate in the oblique vapor deposition method. Further, after oblique vapor deposition, a vertical alignment agent shown in (2) may be applied.

In the above-mentioned orientation treatment, various orientation means may be used alone or
Two or more means may be used in combination.

The orientation-treated display medium of the present invention can be used to efficiently perform selective scattering due to its helical structure, and by selecting the period of the helical structure, color display can be performed. Specifically, these include those that display color using temperature changes in the period of a helical structure, those that utilize phase transition due to heat in polymeric liquid crystal compounds, and those that change the period of a helical structure using electric field response. There is. At this time, the image is retained as long as it is below the glass transition point of the polymeric liquid crystalline compound, and there is no need for repeated writing.The display medium of the present invention can also be provided with a protective film on its surface, and can be used with a heating head, etc. When writing and erasing, it is preferable to use a material that does not undergo thermal deterioration or thermal deformation.

Further, by providing a light absorption layer, it is possible to absorb light other than selective scattering and improve contrast.

Next, in the display medium of the present invention described above, a display method will be described in which the optical density of each layer of the display layer made of laminated polymeric liquid crystalline compounds is independently controlled for each display layer.

FIG. 1 shows the layer structure when n display layers are laminated. The glass transition temperature of the n-th layer is TGn, and the liquid crystal phase transition temperature is TCn. T is the temperature given by the heating element head etc.
An or TAn-1, TGn, T
en and TAn have the following relationship.

TAn>Tf;n>TGn≧TAn−
1 In this case, the n display layers may be sequentially laminated,
They may be randomly stacked.

At this time, when selecting the nth layer of the display layer, TAn-
] By heating the display pixel until it is rapidly cooled, only the nth layer becomes a liquid crystal layer, the other layers are fixed to the amorphous layer, and light is absorbed by the light absorption layer. Next, the display layer n-
When selecting one layer, it is heated to TAn, rapidly cooled to TCn, and slowly cooled from TCn to TGn. Next, T.G.
By rapidly cooling from n, only the nth and −1 layers are fixed by the liquid crystal layer.

A display medium having three display layers will be described below as a typical example. The three display layers each have a thickness of 650 nm.
Display layer with selective scattering nearby (hereinafter referred to as 0 layer), 55
A display layer having selective scattering near 0ni (hereinafter referred to as 0 layer),
Display layer with selective scattering near 450n■ (hereinafter referred to as 0 layer)
, and their respective glass transition temperatures are TGO and T
GO, TGO, and liquid crystal phase transition temperatures are TGO and TG, respectively.
0, TGO, and the temperature given to the display layer by a heating element head etc. is TA+, TA2. FIG. 2 shows a temperature control pattern for singly selecting or singly erasing the 0 layer, ■ layer, and ■ layer when the respective relationships when TA: + are as follows.

TA, >T(:■>TG■≧TA2>TGO>TG◎
≧TA.

>TGO>TGO By controlling the heating temperature and cooling rate as shown above, each display layer can be selected and erased.

Moreover, by controlling the degree of liquid crystallinity by controlling the heating temperature, holding time, and cooling rate, it is possible to continuously change the optical density. Full-color, high-definition image display without color shift is possible.

In selecting each display layer by temperature modulation, more efficient control can be achieved by also using temperature distribution control by heat conduction.

Further, in the method using laser light, it is preferable to control the temperature by controlling the concentration of the light absorbent added to each display layer made of a polymeric liquid crystal compound.

In the present invention, as shown in FIG. 5, two or more heating means, for example, a heating element head 4 are provided in the direction for sequentially recording and erasing on one display layer body A, and the heating means By sequentially selecting pixels and modulating the temperature of the polymer liquid crystal compound, it is possible to independently control the optical density of each display layer for each pixel.

Further, the heating element head used in the present invention has a sixth
As shown in the figure, the heating element head may be composed of a plurality of divided heating element heads 4a.

The display device used in the above display method includes at least the display medium, means for sequentially selecting display pixels of a display layer of the display medium, and two or more heat generating heads arranged in a direction for sequentially recording and erasing information on the display medium. It is preferable to include a heating means having the following.

[Function] According to the present invention, polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures are laminated as a display layer, and the phase transition temperature is different from the glass transition temperature of the polymeric liquid crystalline compound of each display layer. In display media whose temperature ranges up to the transition temperature do not overlap, by modulating the temperature of the polymeric liquid crystalline compound, it becomes possible to independently control the optical density of each display layer. This has made it possible to display full-color images for each pixel of the display medium, and to display high-definition color images of, for example, 12 pels or more without any deviation in one color.

Furthermore, when the polymer liquid crystal compound has a helical structure and display is performed by selective scattering based on the period of the helical structure, the period of the helical structure of the polymer liquid crystal compound in each display layer is set to red (R). , green (G), and blue (B), it is possible to perform a display with good color purity and good contrast. At this time, the efficiency of selective scattering is further improved by making the main axis of the helical structure perpendicular to the display image of the display layer.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A display medium having the configuration shown in FIG. 3 was produced. First, a dichloroethane solution of a polymeric liquid crystal having a structure represented by the following formula (CI) is applied to a glass substrate 1 having a polyimide alignment film that has been subjected to a -axis rubbing treatment, and is dried to a thickness of approximately 10 cm. Layer) Dl was formed. Next, a polyvinyl alcohol (PVA) aqueous solution is applied and dried to a thickness of approximately 0.
After forming the 54 m long separation membrane 8, the following (II
) A dichloroethane solution of polymeric liquid crystal having the structure shown by the formula is applied and dried to form a display layer (11 layers) with a thickness of approximately 10 pm.
D2 was formed. There are 1 layers and 11 layers, respectively.

Furthermore, a PI film having a thickness of 10 m was laminated as a heat-resistant surface protection layer 3 on the display layer (H layer) D2.

Next, a recording method for this display medium will be explained using FIG.

To select the first layer, the display pixels are heated to 290°C by the heating element head 4 installed on the movable bed by the bed moving device 7 and connected to the heating element temperature control device 6, and then heated to 290°C. Rad4 was turned off and the mixture was rapidly cooled to 100°C. Next, by slowly cooling from 100° C. to room temperature using the heating element head 4, a red display was obtained.

Next, in order to select the 11th layer, the display pixels were heated by the heating element head 4, maintained at 270°C, and then rapidly cooled to room temperature, thereby obtaining a green display.

Example 2 An infrared absorber (manufactured by Nippon Kayaku ■) was added to a dichloroethane solution of a polymer liquid crystal represented by the following formula (m) on a glass substrate having a rubbed polyimide alignment film at a ratio of 1 wt% to the polymer liquid crystal. IR-750) was applied, and after drying, a display layer having a thickness of about 10 pm was obtained. A polyimide film with a thickness of about 10μm is laminated on this,
Furthermore, an infrared absorber (manufactured by Nippon Kayaku ■, IR-750) was added to a dichloroethane solution of a polymeric liquid crystal represented by the following formula (TV) at a ratio of 1 wt% to the polymeric liquid crystal, and then dried. A display layer having a thickness of approximately 20 colors was obtained.

When this state was maintained at 90°C for 5 hours and observed with a polarized m-microscope, a 5LlG'' phase was observed.A polyimide film with a thickness of approximately 1 (IB) was further laminated onto the display layer of this substrate. , and further added 1 wt of polymer liquid crystal to a dichloroethane solution of the polymer liquid crystal represented by the following formula (V).
% of infrared absorber (manufactured by Nippon Kayaku, IR-750)
) was applied, and after drying, a display layer having a thickness of about 10 pm was laminated to obtain a display medium.

Next, a method of recording on this display medium using a laser will be explained using FIG. A wavelength of 780 nm generated by a semiconductor laser light source 9 connected to a laser driving device 13
A laser beam of m is irradiated onto the display medium A through a collimator lens 10 and a condensing (objective) lens 11. Output 1
After irradiating at 0 mW, turn off for -1 mW, then turn off at 1 mW.
When irradiated with , only the display layer containing the polymeric liquid crystal compound represented by the formula (II[) was recorded.

Next, when irradiation was performed with 10 Il'il, the power was gradually reduced to 8 mW, and then turned off, only the display layer containing the polymeric liquid crystal compound represented by the formula (V) was recorded. Then, after irradiating with 10 mW, -dan OF
F L, then I irradiated with 5 ■W and turned it off,
Only the display layer containing the polymeric liquid crystalline compound represented by the formula (rir) was recorded.

→ ell According to the display method and device, each display layer of a display medium having a multilayer display layer containing a polymeric liquid crystalline compound is independently selected or multiple display layers are selected or rotated. This allows the color and density to be controlled for each pixel, making it possible to display full-color, high-definition images without color shift.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of the display medium of the present invention, FIG. 2 is a graph showing an example of a temperature control pattern for individually selecting or erasing the display layer of the display medium, and FIG. 3 is an explanatory diagram showing an example of the display layer of the display medium. FIG. 4 is an explanatory diagram showing the display method of the display medium of Example 1, FIG. 4 is an explanatory diagram showing the display method of the display medium of Example 2, and FIG. 6
The figure is an explanatory diagram showing an example of a heating element head. ■...Substrate 2...Light absorption layer 3...
Surface protective layer 4... Heating element head 4a... Divided heating element head 5... Polymer liquid crystalline compound 6... Heating element temperature control device 7... Head moving device 8... Separation membrane 10 ...Collimator lens 11...Condensing lens 12...Lens drive device 13...Laser drive device ~D...Display layers H1-Hn...Alignment layer A...・Display medium 9...laser light source

Claims (11)

[Claims] (1) In a display medium in which polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures are laminated as display layers, the temperature from the glass transition temperature to the phase transition temperature of the polymeric liquid crystalline compounds in each display layer is A display medium characterized by non-overlapping temperature ranges. (2) The display medium according to claim 1, wherein each of the display layers is made of a polymeric liquid crystal compound having a helical structure with a different period. (3) The display medium according to claim 2, wherein the polymeric liquid crystalline compound having a helical structure has a chiral nematic layer. (4) The display medium according to claim 2, wherein the polymeric liquid crystalline compound having a helical structure has a chiral smectic layer. (5) A display layer formed by laminating polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures, and a temperature range from the glass transition temperature of the polymeric liquid crystalline compound of each display layer to the phase transition temperature. 1. A display method comprising controlling the optical density of each display layer independently for each display layer by modulating the temperature of the polymeric liquid crystal compound in a display medium in which the display media do not overlap. (6) The display method according to claim 5, wherein the means for modulating the temperature is a heating element head. (7) The display method according to claim 5, wherein the means for modulating the temperature is a laser beam. (8) A display layer formed by laminating polymeric liquid crystalline compounds having different glass transition temperatures and phase transition temperatures, and a temperature range from the glass transition temperature of the polymeric liquid crystalline compound of each display layer to the phase transition temperature. In a display medium that does not overlap, it has two or more heating means in the direction of sequentially recording and erasing on the display medium, and the heating means sequentially selects each pixel of the display layer and modulates the temperature of the polymeric liquid crystal compound. A display method characterized by independently controlling the optical density of each display layer for each pixel. (9) The display method according to claim 8, wherein the heating means is a heating element head. (10) Polymer liquid crystal compounds having different glass transition temperatures and phase transition temperatures are laminated as a display layer, and the temperature range is from the glass transition temperature of the polymer liquid crystal compound in each display layer to the phase transition temperature. A display medium that does not overlap, a means for sequentially selecting display pixels of a display layer of the display medium, and a heating means having two or more heat generating heads in the direction of sequentially recording and erasing information on the display medium. Characteristic display device. (11) Polymer liquid crystal compounds having different glass transition temperatures and phase transition temperatures are laminated as a display layer, and the temperature range is from the glass transition temperature to the phase transition temperature of the polymer liquid crystal compound in each display layer. A display device comprising: a display medium that does not overlap; and a control means that independently controls the optical density of each display layer by modulating the temperature of the polymeric liquid crystal compound. .