GB2290629A

GB2290629A - Liquid crystal alignment film

Info

Publication number: GB2290629A
Application number: GB9512661A
Authority: GB
Inventors: Munemitsu Abe; Yorihiko Sasaki; Mitsuru Kano; Yoshihiko Ishitaka; Yumiko Sato; Tomomasa Takatsuka
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 1994-06-24
Filing date: 1995-06-21
Publication date: 1996-01-03
Also published as: KR960001816A; DE19523132A1; GB9512661D0; KR0148669B1; TW436650B

Description

2290629 LIQUID CRYSTAL ELEMENT AND ITS MANUFACTURE, FORMATION OF ALIGNMENT

FILM FOR LIQUID CRYSTAL ELEMENT, STAMPING DIE FOR FORMING ALIGNMENT FILM AND ITS MANUFACTUREr AND APPARATUS FOR STAMPING IRREGULAR PATTERN ON ALIGNMENT FILM

The present invention relates to a technique of forming a liquid crystal element exhibiting a wide visual field angle, and particularly to a liquid crystal element having an alignment film capable of realizing a wide visual field angle and its manufacture, and a stamping die for forming an alignment film for a liquid crystal element and its manufacture.

The present invention further relates to an irregular pattern stamp i ng apparatus suitably used for forming the above-described alignment film on a liquid crystal substrate.

A liquid crystal element of a thin film transistor drive type has been extensively known as a high quality image thin type display capable of obtaining a high response speed and full color display. The liquid crystal element of this type, however, has a problem that a visual field angle is narrow.

Conventionally, in the liquid crystal element of this type. there has been known a technique of dividing alignments of liquid crystal molecules for each pixel for widening a visual field angle. Specifically, according to the above-described technique, each dot of R. G and B constituting a pixel has domains different from each other in the rising alignment of liquid crystal molecules when a voltage is applied. In such an alignment division structure,'generally, each dot is divided into two parts, and the divided parts are subjected to different alignment treatments.

This alignment division technique is effective to soften a rapid and asymmetric change in contrast in the vertical direction which has been regarded as a problem in the liquid crystal element of a thin film transistor drive type, and to enlarge a domain in which the reversal of an intermediate tone is not generated. Consequently. this technique has a possibility of providing a liquid crystal element having a wide visual field angle.

One example of a prior art method of manufacturing a liquid crystal element having an alignment division structure will be described below.

As shown in Fig. 13A, an alignment film preliminary layer 2 is formed on the upper surface of a substrate 1, and as shown in Fig. 13Br the alignment film preliminary layer 2 is subjected to a first rubbing treatment.

The rubbing treatment is carried out by a method wherein the upper surface of the alignment film preliminary layer 2 is rubbed with a roller 6 having a rubbing cloth attached around the outer peripheral portion thereof.

Next, as shown in Fig. 13C, a photoresist 3 is applied on the upper surface of the alignment film preliminary layer 2 thus rubbed, and a resist pattern is developed as shown in Fig. 13D. As shown in Fig. 13E. the second rubbing treatment is carried out on the alignment film preliminary layer 2 formed with the resist 3 in the direction reversed to the first rubbing treatment. After that, the resist 3 is removed, to thus obtain the substrate 1 formed with an alignment film 5 shown in Fig. 13F.

Fig. 13G shows one construction example of a liquid crystal element using the alignment. film 5 having the above structure. In this structure, liquid crystal molecules 7 are sealed between a substrate 1 formed with an alignment film 5 on the color filter side and a substrate 1' formed with an aiignment film 5' on the transistor side. The liquid crystal molecules on the alignment film 5 side (on the color filter side) and the liquid crystal molecules on the alignment film 51 side (on the thin film transistor side) are set to be at a pretilt angle so as to be parallel to each other, by alignment control of the alignment film 5 and 51.

The above-described prior art method, however, has the following disadvantage: Namely, in the second rubbing treatment performed by way of the resist 3 after the first rubbing treatment performed over the whole surface, the rubbing must be carried out in the reversed direction using opening portions each having a size being half that of a fine dot. Moreover, in the second rubbing treatment, a large area mask must be used. Consequently, such a rubbing treatment is difficult to be practically realized.

Another problem is that when a photoresist is applied on the rubbing surface and developed, the alignment film tends to be dissolved by an alkali component contained in a development solution, and in this case, even when the alignment film is not perfectly dissolved, at least part of the surface of the film is liable to be altered, thus failing to realize the stable alignment state by the rubbing treatment.

A further problem arises, in which since the remaining photoresist must be removed, the alignment film tends to be further damaged by the removal of the remaining photoresist, and consequently, the initial rubbing state is difficult to be kept. thus failing to ensure stable alignment division over a wide area.

In recent years, a method capable of practically solving the abovedescribed prior art disadvantages has been proposed. Such a method will be described below with reference to the drawings.

First, as shown in Fig. 14A, a low pretilt angle alignment film 11 made of an inorganic material is formed on a substrate 10; a high pretilt angle alignment film 12 is laminated thereon as shown in Fig. 14B; and a photoresist 13 is laminated thereon as shown in Fig. 14C. Subsequently. as shown in Fig. 14D, the photoresist 13 is developed and the high pretilt angle alignment film 12 is etched, followed by the rubbing treatment using a roller 16 as shown in Fig. 14E, thus manufacturing an alignment film.

In this method, since on.ly one rubbing treatment is required and further the high pretilt angle alignment film 12 is subjected to the rubbing treatment after removal of the resist, the alignment state can be stabilized. Moreover, since the low pretilt angle alignment film 11 at the first layer is made of an inorganic material, it becomes possible to reduce the influence of the photoresist on the development solution, and hence to obtain a stable alignment film.

Fig. 14F shows one construction example of the liquid crystal element using the alignment film having such a structure, wherein liquid crystal molecules 17 are sealed between a substrate 10 and low and high pretilt angle alignment film 11, 12 on the color filter side, and a substrate 10 and low and high pretilt angle alignment films 111, 121 on the thin film transistor side. The pretilt angle of liquid crystal on the alignment. film on the color filter side and the pretilt angle of liquid crystal molecules on the alignment film on the thin film transistor side are set to be different from each other by control of the low pretilt angle alignment film 11r 11. and the high pretilt angle alignment film 12, 12'.

As described above, an orientation film for orienting liquid crystal in a specified direction is formed within a substrate of a liquid crystal element. The alignment film has been generally obtained by rubbing a rubbing cloth on the surface of an alignment film preliminary layer (resin film) for giving a specified alignment. In the rubbing treatment, dust is generated and thereby the surface of the alignment film tends to be contaminated by the dust, thus harming the alignment of the alignment film.

To cope with the problems, the present inventors has examined a technique of forming an alignment film by a 6 stamp method.

An alignment film on a substrate of a liquid crystal element is formed on the surface of a substrate main body being high in rigidity such as glass, generally. to a thickness of 1 Am or less for lowering the drive voltage of the liquid crystal element; accordingly, a preferable irregular pattern cannot be formed only by pressing of a die thereon just as the formation of an irregular pattern on a soft and thick plastic film.

Specifically, for forming an irregular pattern on the surface of a thin alignment film. it is required to accurately press a die on a resin made alignment film preliminary layer at a uniform pressure. For this purpose, in the case of pressing using a press, it is required to enhance the flatness and parallelism of a die plate and die set of the press, and to equalize the in-plane pressure distribution upon pressing of the die onto the alignment film preliminary layer.

The method of manufacturing a liquid crystal element having the prior art structure requires a photolithography process. tending to complicate the whole manufacturing process. to deteriorate productivity, and to increase a manufacturing cost.

In the prior art manufacturing method, moreover, residue in the photolithography process tends to be contained in an alignment film, thus causing a fear in reducing the yield of products.

Additionally, in the rubbing process, an alignment f ilm preliminary layer is rubbed with a rubbing cloth and thereby dust is generated. while a clean room is required for masking by photolithography. and consequently, the management of the whole process is complicated, and it becomes difficult to keep high quality through the whole process.

In the prior art method described with reference to Fig. 13, the resist 3 is formed after the first rubbing treatment and openings are formed by patterning of the resist, after which the alignment film 2 initially rubbed is partially rubbad again in another direction over the openings of the resist 3 in the state that part of the alignment film 2 initially rubbed is protected. As a result, since the domains of the resist 3 in openings are twice rubbed, portions of the resist 3 near the openings cannot be rubbed at a high accuracy. In this rubbing treatment, the treated magnitude of a pixel is limited to about 100 AmX100 um.

Fig. 15 is a plan view showing the rubbing directions of alignment films in one example of a liquid crystal element in which the rubbing direction of the alignment film on the color filter side is different from the rubbing direction of the alignment film on the thin film transistor side, wherein the rubbing direction A is perpendicular to the rubbing direction B. Incidentally. the liquid crystal element having such a structure has a visual field angle characteristic shown in Fig. 16. and has a disadvantage that the vidual field angle is narrow in a specified direction. The visual field angle characteristic shown in Fig. 16 has an area of CR k1O.

Here, the wording "CR" means "contrast", and is defined in the following equation, for a normally white type liquid crystal (white display upon applying of no voltage, and black display upon applying of voltage).

CR = ltransmissivity upon applying of no voltage)/(transmissivity upon applying of voltage) CR is also defined by the following equation. for a normally black type liquid crystal (black display upon applying of no voltage, and white display upon applying of voltage).

CR = (transmissivity upon applying of voltage)/(transmissivity upon applying of no voltage) In the liquid crystal element in which the combination of the rubbing direction of an alignment film on the color filter side and the rubbing direction of an alignment film on the thin film transistor side is different for each pixel of each thin film transistor, a substrate including one alignment film and another substrate including another alignment film are accurately positioned and joined to each other while eliminating the generation of any error in the order of pixel unit, and liquid crystal is sealed therebetween. At this time. if the above-described positioning accuracy is only slightly poor, it becomes difficult to obtain a desirable alignment of liquid crystal.

incidentally, the twisting angle of an STN (Super Twisted Nematic) liquid crystal is generally in the range of from 180to 240 -, and it may be considered that the visual field angle can be enlarged by increasing the twisting angle.

However, to obtain the twisting angle of 240 in the STN liquid crystal, the pretilt angle of liquid crystal molecules must be 6 or more, and in the alignment film subjected to the prior art rubbing treatment using a rubbing cloth, it is difficult to stably form the pretilt angle of 6 or more.

A method has been known of forming projecting portions at a tilting angle of 6 or more by a special evaporation called the tilting evaporation thereby realizing a high pretilt angle; however, this method is high in manufacturing cost, and is not suitable for mass-production.

incidentally, the present inventors have found that even when a high flatness stamping die for forming an alignment film is pressed on an alignment film preliminary layer, the surface shape of the stamping die is sometimes not perfectly stamped on the alignment film preliminary layer.

The reason for this is that as shown in Fig. 25A, a transparent substrate 102 made of glass formed with an alignment film preliminary layer 101 has generally fine waviness, irregularities or tilting, and thereby it is uneven in its thickness, as a result of which even when it is sufficiently subjected to surface finish such as grinding, slight waviness, irregularities or tilting remain on the upper surface of the substrate 102.

Specifically, when the pressing is performed using a stamping apparatus including a.press base body 103 having a high flatness, a sheet-like elastic member 104 stuck on the press base body 103 and a plate-like die member 105, a domain where the die member 105 is not pressed on the alignment film preliminary layer 101 as shown in Fig. 25B is generated. This domain leads to a failure in al--Lgnment, thus causing a failure in display of the liquid crystal display.

Moreover, in the case where an irregular pattern is formed on the alignment film preliminary layer 101 by the die member 105 and then the die member 105 is separated from the alignment film preliminary layer 101, if the die member 105 and the alignment - film preliminary layer are made of materials liable to be easily bonded to each other, part of the alignment film preliminary layer 101 is peeled and stuck on the surface of the die member 105. to damage part of the alignment film, thus causing unevenness in display. In addition, since the alignment film preliminary layer is generally made of aromatic polyamide, the above-described problem in peeling of the alignment film is significantly enlarged in the case where the die member 105 is made of nickel.

MY OF THE INVENTION In view of the foregoing, an object of the present invention is to provide a liquid crystal element and its manufacture; formation of an alignment film for a liquid crystal; and a stamping die for forming an alignment film for a liquid crystal element and its manufacture, wherein an alignment film having a plurality of uniform alignment domains can be manufactured and thereby a liquid crystal display element having a wide visual field angle can be obtained.

Another object of the present invention is to provide a stamping apparatus enabling smooth stamping of an irregular pattern and preventing the peeling of part of an alignment film preliminary layer upon separation from a stamping die thereby eliminating the generation of peeling failure, even when an alignment. film is formed on a substrate having slight tilting. irregularities or waviness.

To achieve the above object, according to a preferred mode as described in claim 1, there is provided a liquid crystal element comprising:

a pair of substrates disposed so as to face to each other, and having respective alignment films on the facing surfaces-thereof; and liquid crystal held betweean said substrates; wherein a surface shape of said alignment film formed on at least one of said substrates is formed by pressing of a die, and said alignment film formed with the surface shape by pressing of the die has a plurality of uniform alignment domains which are different from each other in the emergent direction or emergent magnitude of a pretilt angle of liquid crystal within an effective display plane.

According to a preferred mode as described in claim 2, there is provided a liquid crystal element defined in the - 13 preferred mode as described in claim 1, wherein said alignment film formed on one of said substrates and having a plurality of said uniform alignment: domains has two directional uniform alignment domains in which the emergent directions of the pretilt angle of liquid crystal are approximately parallel to each other, and said alignment film formed on the other of said substrates has a pretilt angle lower than said pretilt angle in one of said substrates.

According to a preferred mode as described in claim 3, there is provided a liquid crystal element defined in the preferred mode as described in claim 1 or 2. wherein the surface shape of said alignment film is formed by collection of a plurality of projecting portions having tilting surfaces, and said tilting surfaces of said projecting portions function as a means of adjusting the pretilt angle of liquid crystal.

According to a preferred mode as described in claim 4, there is provided a liquid crystal element defined in the preferred mode as described in any of claims 1 to 3, one uniform alignment domain having an emergent direction or emergent magnitude of a pretilt angle of liquid crystal is formed by the collection of first projecting portions having tilting surfaces extending at a tilting angle, and the other uniform alignment domain having an emergent direction or emergent magnitude of a pretilt angle different from that in said one uniform alignment domain is formed by collection of a plurality of second projecting portions having tilting surfaces extending at an angle different from that of said tilting surfaces of said first projecting portions.

According to a preferred mode as described in claim 5, there is provided a liquid crystal element defined in the preferred mode as described in any of claims 1 to 4. wherein the surface shape of an alignment film is formed by collection of projecting portions having tilting surfaces. and the tilting angle of the tilting surfaces of said projecting portions formed on the surface of said alignment film is specified at 6 or more.

According to a preferred mode as described in claim 6, there is provided a method of manufacturing a liquid crystal element having liquid crystal. held between a pair of substrates, said substrates being disposed so as to face to each other and having respective alignment films on the facing surfaces thereof; comprising:

an alignment film preliminary layer forming process of forming an alignment film preliminary layer on the surface of each of said substrates; and a shape imparting process of pressing a die capable of forming a plurality of uniform alignment domains different from each other in an emergent direction or emergent magnitude of a pretilt angle of liquid crystal within an effective display plane on the surface of said substrate. on the surface of at least one of said alignment film preliminary layer.

According to a preferred mode as described in claim 7, there is provided a method of manufacturing a liquid crystal element having liquid crystal held between a pair of substrates, said substrates being disposed so as to face to each other and having respective alignment films on the facing surfaces thereof; comprising:

an alignment film preliminary layer forming process of forming an alignment film preliminary layer on the surface of each of said substrates; and a first shape imparting process of pressing a die capable of forming uniform alignment - domains nearly equal to each other in an emergent direction or emergent magnitude of a pretilt angle of liquid crystal within an effective display plane on the surface of said substrate, on the surface of at least one of said alignment film preliminary layer; and a second shape imparting process of pressing a die capable of forming uniform alignment domains different in the emergent direction of the pretilt angle from those obtained in said first shape forming process, on the surface of said alignment film preliminary layer.

According to a preferred mode as described in claim 8. there is provided a method of manufacturing a liquid crystal element defined in the preferred mode as described in claim 6 or 7, which further comprises a shape imparting process of pressing said die on one of said alignment film preliminary layers, and a process of pressing an approximately cylindrical roller formed at least on the surface with an elastic body on the other of said alignment film preliminary layers.

According to a preferred mode as described in claim 9, there is provided a method of manufacturing a liquid crystal element defined in the preferred mode as described in any of claim 6 to 8, wherein said uniform alignment domains are formed using a stamping die in. which a plurality of projecting portions having tilting surfaces are formed on the surface and the tilting angle of said tilting surfaces of said projecting portions is specified at 6 or more.

According to a preferred mode as described in claim 10, there is provided a method of manufacturing a liquid crystal element defined in the preferred mode as described in any of claims 6 to 9, wherein said shape imparting process is carried out using a die on the surface of which a plurality of first portions each forming one uniform alignment domain and a plurality of second portions each forming the other uniform alignment domain are formed, said first portion being constituted of collection of a plurality of projecting portions with tilting surfaces having the same tilting direction and the same tilting angle, and said second portion being constituted of a plurality of projecting portions with tilting surfaces having a tilting direction and a tilting angle different from said tilting direction and said tilting angle of said first portion.

According to a preferred mode as described in claim 11, there is provided a stamping die for forming an alignment film for a liquid crystal element, which is pressed on the surface of a resin made alignment film preliminary layer formed on a substrate for a liquid crystal element for forming a plurality of project.ing portions on the surface of said alignment film preliminary layer, comprising:

irregularities repeatedly formed on the surface of said stamping die along a first direction; and irregularities repeatedly formed on the surface of said stamping die along a second direction crossing said first direction, wherein the tilting direction of said tilting surfaces formed by said irregularities are specified for each of a plurality of divided domains formed on the surface of said stamping die.

According to a preferred mode as described in claim 12, there is provided a stamping die for forming an alignment film for a liquid crystal element defined in the preferred mode as described in claim 11, wherein the tilting angle of said tilting surfaces of said projecting portions formed on the surface of said stamping die is specified at 6 or more.

According to a preferred mode as described in claim 13. there is provided a stamping die for forming an alignment film for a liquid crystal element defined in the preferred mode as aescribed in claim 11 or 12, wherein said divided domain of said stampingdie is equivailent to one of said projecting portions formed on said stamping die.

According to a preferred mode as described in claim 14, there is provided a method of manufacturing astamping die for forming an alignment film for a liquid crystal element comprising:

a first heating process of heating a stamping film made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a first stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along an optional direction, on said stamping film; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals, and emitting ultraviolet rays to said stamping film through said mask; a second heating process of heating said stamping film after said ultraviolet ray emitting process; a second stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process,'on said stamping film; and a process of pressing said stampingdie on said stamping film after said second stamping process, thereby stamping the surface shape of saidstamping film on said stamping die.

According to a preferred mode as described in claim 15, there is provided a method of forming an alignment film for a liquid crystal element, comprising:

a first heating process of heating an alignment film preliminary layer made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a first stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along an optional direction, on said alignment film preliminary layer; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals,, and emitting ultraviolet rays to said alignment. film preliminary layer through said mask; a second heating process of heating said operation film preliminary layer after said ultraviolet ray emitting process; and a second stamping process of pressing, a single domain s-L.a--,iping die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process, on said alignment. film preliminary layer.

According to a preferred mode as described in claim 16, there is provided a method of manufacturing a stamping die for forming an alignment film for a liquid crystal element, comprising:

a first heating process of heating a stamping film made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a first stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along an optional direction, on said stamping film; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals, and emitting ultraviolet rays to said stamping film through said mask; a second heating process of heating said stamping film after said ultraviolet ray emitting process; and a second stamping process of pressing. a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process, on said stamping film.

According to a preferred mode as described in claim 17. there is provided a method of manufacturing a stamping die for forming an alignment film for a liquid crystal element, comprising:

a first heating process of heating a stamping film made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a first stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along an optional direction, on said stamping film; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals, and emitting ultraviolet rays to said stamping film through said mask; a second heating process of heating said stamping film after said ultraviolet ray emitting process; and a second stamping process of pressing, a single domain stampinS die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process, on said stamping film; wherein the surface shape is formed on said stamping die by electrocasting using said stamping film after said stamping process as an original template.

According to a preferred mode as described in claim 18, there is provided a stamping apparatus used for pressing a die member having an irregular.pattern on an alignment film preliminary layer on a substrate thereby stamping the irregular pattern on the upper surface of said alignment film preliminary layer, comprising:

a press base body made of a rigid body; an elastic member disposed so as to face to said press base body; and a sheet-like die member provided on the side not facing to said press base body of said elastic member.

According to a preferred mode as described in claim 19, there is provided a stamping apparatus defined in the preferred mode as described in claim 18, wherein said elastic member is mounted on the surface of said press base body, and said die member is mounted on the surface of said elastic member.

According to a preferred mode as described in claim 20, there is provided a stamping apparatus for forming an irregular pattern on an alignment film defined in the preferred mode as described in claim 18 or 19, wherein said press base body is formed in a flat shape.

According to a preferred mode as described in claim 21, there is provided a stamping apparatus for forming an irregular pattern on an alignment film defined in the preferred mode as described in claim 18 or 19, wherein said press base body is formed in a roller shape.

According to a preferred mode as described in claim 22, there is provided a stamping apparatus defined in the preferred mode as described in any of claims 18 to 21, wherein said die member is formed to a thickness in the range of from 0.001 mm to 0.2 mm.

According to a preferred mode as described in claim 23, there is provided a stamping apparatus defined in the preferred mode as described in any of claims 18 to 22, wherein a coating layer made of gold, gold alloy, copper or copper alloy is formed on the surface of said die member.

Hereinafter, the function of the present invention will be described.

According to the preferred mode as described in claim 1, since the surface shape of an alignment. film is imparted by pressing of a die, it is possible to eliminate the rubbing process of generating dust, to accurately impart an optional surface shape in accordance with the shape of the die to an alignment film, and to impart uniform alignment domains by an optional number; and further. since a plurality of uniform alignment domains are formed in an effective display plane, each visual field angle characteristic in accordance with each uniform alignment domain can be obtained. and a preferable visual field angle characteristic in all the directions can be optained as a whole.

Since the surface shape of an alignment film is determined depending on the shape of the die, it is possible to easily form even the surface shape with irregularities of a magnitude of several t4mX gm, and hence to provide a high density liquid crystal element.

Since the surface of an alicnment film is formed without a resist used in the conventional method, it is possible to eliminate the problems such as disturbance of the surface shape of the alignment film and the damage of the underlayer alignemnt film which have been conventionally generated upon removal of the resist.

In the prior art structure of controlling a pretilt angle of liquid crystal by the surface shape of an alignment film formed by rubbing treatment, when the rubbing treatment is performed by a plural numbers using a resist as a mask for realizing a wide visual field angle, the surface shape of the aiignment film at the boundary between the domain subjected to the first rubbing treatment and that subjected to the second rubbing treatment is disturbed, so that the width of the disturbed alignment of liquid crystal in the boundary is widened. on the contrary, according to the method of forming the surface shape of the alignment film by the die, the boundary in the aligned direction can be perfectly controlled, so that the width of the disturbed alignment is narrowed, thus improving the display quality.

Since the surface shape corresponding to the irregularities of a die can be imparted onto an alignment film, the number of uniform alignment domains to be formed for each pixel can be significantly increased as compared with the conventional manner. For example, for a pixel of 100 umX100 um, two pieces of domains can be formed in the prior art; however, in the structure of the surface shape of the alignment film obtained by pressing of a die. since the irregularities formed on the surface of the die can be accurately stamped in the order of gm, several to several tens or more of alignment. domains can be easily formed. Additionally, in this operation. the necessity of the positioning between the pixel and the alignment film is eliminated.

According to the preferred mode as described in claim 2, two directional uniform alignment domains in which aligned directions are substantially parallel to each other are formed on each pixel, and further the pretilt angle in another alignment film is low, so that when the substrates are superimposed, the positioning does not require the accuracy so much.

According to the preferred mode as described in claim 3 or 4, since the surface shape of an alignment film is formed by collection of the tilting surfaces of projecting portions, it is possible to specify the pretilt angle of liquid crystal by the tilting angle, and to specify the pretilt angle for each uniform alignment domain by the tilting surfaces of the projecting portions in each domain.

According to the preferred mode as described in claim 5, since the pretilt angle of liquid crystal molecules is specified at 6' or more, the twisting angle of a liquid crystal molecules can be set at 240 or more. The twisting angle can be realized for an STN liquid crystal.

According to the preferred mode as described in claim 6, since the surface shape of an alignment film can be imparted by pressing of a die, an optional surface shape of an alignment film in accordance with the shape of the die can be accurately obtained, and the orientation film having uniform alignment domains by the desirable number can be obtained. Moreover, since a plurality of uniform alignment domains can be formed within an effective display plane, the visual field angle corresponding to each uniform alignment domain ca'n be obtained. thus obtaining an excellent liquid crystal element having a preferable visual field angle in all the directions as a whole.

According to the preferred mode as described in claim 7, in addition to the first sape imparting process described in the preferred mode as described in claim 6, a second shape imparting process is provided of pressing a die capable of forming uniform alignment domains different in the emergent direction of the pretilt angle from those obtained in the first shape forming process, on the surface of the alignment film preliminary layer, so that different uniform alignment domains can be positively formed on a substrate, 28 - and thereby a liquid crystal element excellent in a preferable visual field angle in all the directions as a whole can be obtained.

According to the preferred mode as described in claim 8, an alignment film with a surface shape having a low pretilt angle can be easily formed by pressing a roller having an elastic body on an alignment film, and thereby a liquid crystal element having upper and lower substrates being easy in the positioning can be provided.

In the case of using a stamping die in which the tilting angle of tilting surfaces of projecting portions is 6 or more as described in the preferred mode as described in claim 9,'the.pretilt angle of liquid crystal becomes 6 - or more, and accordingly, the liquid crystal having a twisting angle of 240 - or more can be obtained. Thus, a liquid crystal element having a wide visual field angle can be obtained.

Moreover, in the case of using a stamping die in which a plurality of projecting portions having tilting surfaces described in the preferred mode as described in claim 10 are collected, a plurality.of uniform alignment domains are easily formed on an alignment film, thus easily controlling the pretilt angle of liquid crystal.

According to the preferred mode as described in claim 11 or 12, there is provided a die used for forming an irregular surface shape on an alignment film preliminary layer on a substrate, wherein the tilting surfaces of the irregularities formed on the - alignment film preliminary layer are specified for each of a plurality of domains, so that the alignment of liquid crystal is adjusted for each of the above domains. Accordingly, it is possible to manufacture an alignment film having a plurality of domains in each of which the alignment of liquid crystal is specified, and hence to obtain a liquid crystal element in which the aliqnment is specified for each domain.

The twisting angle of liquid crystal can be increased by specitying the tilting angle of the tilting surfaces of each projecting portion on the surface at 6 or more.

In the preferred mode as described in claim 13. since one projecting portion is taken as one uniform alignment domain, a plurality of domains, each having a minimum size capable of being formed on the die can be formed on the alignment film, and the different alignment can be imparted to liquid crystal for each domain. As a result, it is possible to change the alignment of liquid crystal molecules in an extremely fine domain as compared with the conventional one, and hence to provide a liquid crystal element having a wide visual field angle.

In the method of manufacturing a transfer die for forming an orientation film for a liquid crystal element according to the preferred mode as described in claim 14, a stamping die used for formation of atl alignment f ilm, subjected to alignment division can be manufactured at a low cost. As compared with the method of forming an alignment film by the rubbing treatment, the controllability is high, and it is possible to form a stable and high accurate alignment film having a high pretilt angle.

Differently from the method of forming an alignment film by the rubbing treatment, the shape imparting process is performed in a clean environment without generation of dust.

In t-he method of forming an alignment film using the die, moreover, the manufacturing cost can be significantly reduced as compared with a method of preparing grating using photolithography.

In the method of forming an alignment film for a liquid crystal element according to the preferred mode as described in claim 15, an alignment film can be formed without manufacture of astamping die having the surface shape aligned in a plurality of directions, and further as compared with the method of forming an alignment film by the rubbing treatment, the controllability is high, and it is possible to to= a stable and accurate alignment film having a high pretilt angle.

In addition, the manufacturing cost can be significantly reduced as compared with a method of preparing grating using photolithography.

In the method of manufacturing a stamping die for forming an alignment film for a liquid crystal element according to the preferred mode as described in claim 16, the stamping die can be manufactured without the stamping base die, thus reducing the manufacturing cost.

In the method of manufacturing a stamping die for forming an a!-4gn-.,ient film for a liquid crystal element according to the preferred mode as described in claim 17, the surface shaDe can be accurately stamped from a stamping base die to a die using electro-casting.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which; Fig. 1 is a sectional view showing the state in which an alicnment film preliminary layer is formed on a substrate; Fig. 2 -'s a side view showing the state in which a plurality of projecting portions are formed on an alignment film preliminary layer using a stamping die; Fig. 3 is a partially enlarged perspective view showing irregularities of thestamping die; Fig. 4 is a partially enlarged view showing an irregular pattern formed on an alignment film preliminary layer using a stamping die; Fig. 5 is a partially enlarged perspective view for illustrating the shape of the irregular pattern shown in Fig. 4; Fig. 6 is a partial sectional view of the irregular pattern shown in Fig. 5; Fig. 7 is a partially enlarged sectional view showing another irregular pattern formed on an alignment film preliminary layer; Fig. 8 is a partially enlarged perspective view showing a further irregular pattern on an alignment film of the present invention; Fig. 9 is an equal contrast curve capable of realizing the twisting of 270 in STN liquid crystal; Fig. 10 is an equal contrast curve capable of realizing the twisting of 180 in STN liquid crystal; Figs. 11A to 11G are process diagrams showing a method of manufacturing astamping die for forming an alignment film of a liquid crystal element; Fig. 12 is a plan view showing one example of a mask used for manufacture of a stamping die for forming an alignment film for a liquid crystal element; Fig. 13A is a process diagram of a prior art method showing an alignment film preliminary layer formed on a substrate;

Fig. 13B is a process diagram of the prior art method showing the state in which the alignment film preliminary layer is subjected to alignment treatment by rubbing;

Fig. 13C is a process diagram of the prior art method showing the state in which a resist is formed;

Fig. 13D is a process diagram of the prior art method showing the state in which part of the resist is removed;

Fig. 13E is a process diagram of the prior art method showing the state in which the second rubbing is performed on the resist part of which is removed;

Fig. 13F is a process diagram of the prior art method showing the alignment film obtained;

Fig. 13G is a sectional view showing an essential portion of a liquid crystal in which each domain is subjected to alignment division; Fig. 14A is a process diagram of another prior art method showing an alignment film having a low pre-tilt angle formed on a substrate; Fig. 14B is a process diagram of the another prior art method showing an alignment film having a high pre-tilt angle is formed on the alignment film having a low pre-tile angle;

Fig. 14C is a process diagram of the another prior art method showing a resist formed on the alignment film having a high pre-tilt angle;

Fig. 14D is a process diagram of the another prior art method showing the state that part of the resist is removed and further part of the alignment film having a high pretilt angle is removed;

Fig. 14E is a process diagram of the another prior art method showing the state in wnich rubbing is performed oil the alignment film having a high pre-tilt angle part of which is removed;

Fig. 14F is a sectional.view showing an essential portion of a liquid crystal in which domain is subjected to alignment division; Fig. 15 is a view for illustrating a prior art structure in which alignment treatment is performed in two directions perpendicular to each other;

Fig. 16 is a view showing a visual field angle characteristic of liquid crystal having the alignment film - 35 shown in Fig. 15; Fig. 17 is a side view showing a first example of a stamping apparatus of the present invention; Fig. 18 is a side view showing the state in which an irregular pattern is stamped on an alignment. film preliminary layer formed on a substrate using the stamping apparatus shown in Fig. 17; Fig. 19 is a side view showing a second example of a stamping;.apparatus of the present invention; Fig. 20 is a side view showing the state in which an irregular pattern is stamped on an alignment film preliminary layer formed on a substrate using the stamping apparatus shown in Fig. 19; Fig. 21 is a side view showing a third example of a stamping apparatus of the present invention; Fig. 22 is a side view showing the state in which an irregular pattern in stammed on- an alignment film preliminary layer formed on a substrate using the stamping apparatus shown in Fig. 21; Fig. 23 is a perspective view in which one example of the alignment film is enlarged; Fig. 24A is a view showing the result of an interference light measurement test performed in Test Example; Fig. 24B is a view showing the result of a separation test performed in Test Example; Fig. 25A is a side view showing one example of a prior art stamping apparatus; and

Fig. 25B is a side view showing the state in which stamping is performed using the prior art stamping apparatus

Hereinafter, the present invention will be described in detail with reference to the drawings.

A liquid crystal element is manufactured in the following procedure: First, a resin solution is applied onto the upper surface of a substrate formed of glass or the like in a rectangular shape as shown in Fig. 1,, by spincoating, screen printing or offset printing, and it is dried by baking, to thus form an alignment film preliminary layer 21.

The alignment film preliminary layer 21 may be subjected to pre-baking and post-baking, as needed. The prebaking and baking can be performed by a method wherein the substrate 20 formed with a resin solution is heated for about 30 minutes at 80C and then heated for one hour at about 180C. Alternatively, the substrate 20 is preliminarily heated at about 80'C, being coated with a resin solution by screen printing, and is baked.

In the above-described screen printing, a resin solution is applied onto the substrate 21 in such a manner that a printing squeegee is moved by way of a screen provided on the substrate 20 in the longitudinal, transverse, or tilting direction of the substrate 21 at a specified speed, for example, 20 cm/sec.

The material of the substrate 20 is not limited to glass, and it may include those used for the liquid crystal element of this type, for example, ceramics. The shape of the substrate 20 is also not limited to the rectangular one, and it may include an optional one.

The alignment film preliminary layer 21 is preferably formed of a thermosetting resin being small in influence exerted on a stamping die (described later) such as epoxy resin, or a photo-curing resin. However,, it may be formed of a thermoplastic resin. In this case, the thermoplastic resin preferably has a glass transition point in the range of from 130 to 280C for ensuring the heat-stability of the liquid crystal element and also keeping the stability of the resin against heat treatment performed for stamping of an irregular pattern thereto by the stamping die (described later). The alignment film preliminary layer 21 made of the material satisfying such requirements is excellent in heat resistance and it can be easily stamped with an irregular pattern (described later).

Next, a roller-like stamping die 23 shown in Fig. 2 is disposed on the upper surface of the alignment film preliminary layer 21 in the direction perpendicular to the longitudinal direction of the substrate 20. In such a state, at least one of the substrate 20 and the stamping die 23 is heated to a temperature near a glass transition temperature of the alignment. film preliminary layer 21, and then the stamping die 23 is pressed on the alignment film preliminary layer 21 and simultaneously rolled in the longitudinal direction of the substrate 20.

The stamping die 23 is composed of a roller main body made of metal or the like, on the surface of which a resin film is formed. As shown in Fig. 3, on the surface of the resin film of the stamping die 23, an irregular pattern in which projecting portions 25 and recessed portions 26 are continuously formed in an alignment state. The irregular pattern includes irregularities along a first direction and irregularities along a second direction crossing the first direction, as shown in Fig. 3. in this irregular pattern, a pitch P1 of the irregularities along the first direction is specified to be shorter than a pitch P2 of the irregularities along the second direction.

The irregular pattern of the.,st--amping die 23 can be thus stamped on the surface of the alignment- film preliminary layer 21, to form an irregular pattern shown in Figs. 4, 5 and 6 on the upper surface of the alignment film preliminary layer 21. In the projecting portions 27 constituting the irregular pattern, as shown in Fig. 5, the pitch P1 of the irregularities along the first direction is specified to be shorter than the pitch P2 of the irregularities along the second direction, and a tilting angle e of a ridgeling of a tilting surface R2 extending along the second direction from the vertex portion of the projecting portion 27 is formed at, for example 20 or more.

In this irregular pattern having the structure shown in the ficmres, the pitch 21 is specified at, for example 3 gm or less and the pitch P2 is, for example 50 gm or less. The pitches P1 and P2, however, are not limited thereto. and for example, they may be specifiedat 1.2 gm or less, and 20 1= or less, respectively.

In this irregular pattern, moreover, as shown in Fig. 6, each projecting portion 27 of the irregularities along the second direction is formed in an approximately triangular shape being asymmetric in the right and left. Namely, the triangular shape of the projecting portion 27 is determined such that the angular ratio r2/rl is not equal to 1. wherein - 40 r2 and ri are respectively the right and left angles divided from the vertical angle of the triangle of the projecting portion 27 by a vertical line A extending from the vertex of the triangle. The projecting portion 27 may be formed into a shape similar to a sine wave, comb-shape or triangular shape, and of these shapes, the triangular shape is most suitable for improving the alignment of liquid crystal. In this triangular shape of the projecting portion 27, the vertex portion may be rounded or flattened. In the case where the projecting portion 27 is formed in a triangular shape, the above-described angular ratio r2/rl can be specified at 1.2 or more as shown in Fig. 6.

Incidentally. upon the above-described stamping operation, it is desirable that after the stamping die 23 is pressed on the alignment film preliminary layer 21, the layer 21 is heated at a temperature near the glass transition temperature for a specified time, and the stamping die 23 is then rolled for stamping of the irregular pattern. The pressing force of the stamping die 23 applied at this time is suitably set in accordance with the hardness of the alignment film preliminary layer 21, and is preferably set at, for example, about 50 kg/cm. The moving speed of the stamping die 23 is preferably set at such a value as to perfectly stamping the irregular pattern, for example, at about 15 mm/sec.

After the stamping die 23 is rolled to the center portion of the substrate 20, the substrate 20 and the stamping die 23 are cooled while the stamping die 23 is pressed on the substrate 20, and when they are cooled to a temperature not more than the glass transition temperature, the transfer die 23 is removed from the stamping film preliminary layer 21. The stamping die 23 is then turned by and moved to the opposed end of the substrate 20. after which it is rolled from the end portion side in the same manner as described above for stamping of the irregular pattern. Alternately. after the stamping is completed at the center portion, the stamping die 23 is reversed by 180 over the substrate 20 for changing the direction of the irregular pattern, and it is rolled from the center portion for J stamping of the irregular pattern in the same manner as described above. Thus, on the, remaining portion of the substrate 20, a number of projecting portions 28 having tilting surfaces R3 different in the direction from tilting surfaces R2 of the projecting portions 27 of the irregular pattern previously formed, to thus form an alignment film 29. The alignment film 29 has an uniform alignment domain B1 composed of collection of a number of the projecting portions 27 having the tilting surfaces tilting at the same tilting angle, and an uniform alignment domain B2 composed of the collection of a number of the projecting portions 28 having the tilting surfaces tilting at the tilting angle different from the above- described tilting angle of the tilting surfaces in the uniform alignment domain Bl.

Two pieces of the substrates 20 with the alignment films 29 thus obtained are superimposed at a specified interval by way of a spacer or the like, and liquid crystal is sealed therebetween. to thus form a liquid crystal cell.

By forming a number of the projecting portions on the surface of the alignment film preliminary layer 21 as described above, the conventional rubbing treatment using a rubbing cloth is not required to be performed. to eliminate the process in which dust is generated. thus improving the manufacturing yield, and also the optional surface shape corresponding to that of the s,tamping die 23 can be imparted on the surface of the alignment film.

Moreover, liquid crystal molecules corresponding to respective domains formed with the projecting portions 27, 28 being different in the direction of the tilting surface have respective pretilt angles different from in the direction. so that two uniform liquid crystal alignment domains can be formed in one pixel system. Accordingly, since the visual field angle characteristic corresponding to respective domains can be obtained, the visual field angle characteristic being wider than conventional as a whole can be obtained.

In this example, the alignment film preliminary layer 21 is divided into two domains, and a number of the projecting portions 27 or 28 having the tilting surfaces tilting at the same direction are formed in each domain. The layer 21 on the substrate 20 may be divided into a plurality of domains, and a number of projecting portions having a specified tilting direction can be formed on each of a plurality of the divided domains. In this case, a plurality of domains are set on the surface of the stamping die 23, and projecting portions having tilting surfaces tilting in the same direction are formed on each of a plurality of domains. Such a stamping die is rolled on the alignment film preliminary layer 21 once, so that a number of domains each including a plurality of projecting portions having tilting surfaces tilting in the same direction can be formed on the surface of the alignment film preliminary layer 21. In addition, since the pretilt angles (described later) of liquid crystal is specified on the base of the tilting surfaces R2 and R3 of the projecting portions 27 and 28, there can be obtained an alignment film having a plurality of domains each having alignment corresponding to the tilting directions of the tilting surfaces R2 and R3 of the projecting portions 27 and 28.

For example, as shown in Fig. 7, three pieces of the projecting portions 27 having the tilting surfaces R2 tilting at an angle are continuously formed on a domain, and on each side of the domain, three pieces of the projecting portions 28 having the tilting surfaces R3 tilting at another angle are continuously formed, to form an alignment film 29' on the surface of which a number of irregular patterns are orderly arranged. A stamping die 30 used in this case has an irregular shape shown in Fig. 7 in which recessed portions 27' corresponding to the projecting portions 27 and recessed portions 281 corresponding to the projecting portions 28 are formed.

By pressing such a stamping die 30 on the alignment film preliminary layer 21 once,, a number of uniform alignment domains each having tilting surface tilting at the same angle can be easily formed on the alignment film preliminary layer 21.

Fig. 8 shows another example of a stamping die for forming an alignment film. In the stamping die 31, a number of projecting portions 32 each having a crosssectional shape similar to a sine wave are formed in an alignment state. In this example, the tilting angle of the ridgeling of atilting surface extending along the second direction from the vertex portion of the projecting portion 32 is formed to be more than that in the stamping die in the previous example. Using the stamping die 31 having the projecting portions 32 of such a high tilting angle, an alignment film having a large pretilt angle can be easily formed.

In particular. the setting of the tilting angle of the tilting surface of the projecting portion at a value higher than 20 or more, is effective for the STN liquid crystal.

In general. the twisting angle of the STN liquid crystal is in the range of from 180 to 240; however, by increasing the twisting angle more than the above-described range, the visual field angle can be increased. To set the twisting angle of the STN liquid crystal at 240 or more, the pretilt angle of the liquid crystal molecules are required to be set at 15 or more. In an alignment film subjected to rubbing treatment using a rubbing cloth. however, the pretilt angle of 15 or more cannot be realized.

On the other hand, according to the method of using the stamping die having the above-described structure. the projecting portions 27, 28 having the tilting angle of 20 or more can be easily formed on a large scale, and accordingly, the pretilt angle of liquid crystal molecules can be easily controlled at a value of 20 or more. Thus, in the STN liquid crystal, the twisting angle of 270 can be realized, and thereby a liquid crystal element of a wide visual field angle can be produced on a large scale.

Fig. 9 is an equal contrast curve of an STN liquid crystal having a twisting angle of 270. which shows the dependency of an visual field angle on a visual field angle. The numerals around the concentric circles (0', W, 180, and 270) show the directions along which the liquid crystal element is viewed. The concentric circle indicates the tilting degree from the normal line of the surface of the display element for each 10. and the outermost circle indicates the state tilting from the normal line by 60.

Fig. 10 is an equal Contrast curve of an STN liquid crystal having a twisting angle of 180, in which the slant line portion shows the reversed domain. Prom this figure, it is revealed that the twisting angle of 270 in the STN liquid crystal can be realized and a high contrast domain can be widely obtained.

The alignment film having a plurality of domains each having the same alignment is manufactured in the following procedure.

First, a thermoplastic ultraviolet ray hardening resin is flatly applied onto on a substrate of a stamping base die. to form a stamping film.

As the thermoplastic ultraviolet ray hardening resin, there may be used polyvinyl cinnamate or polyvinyl benzalacetophenone.

Next, in a first heating process, the stamping base die is heated, to soften the stamping film.

On the other hand, a single domain stamping die 18 on which a plurality of irregularities are repeatedly formed along an optional direction is separately prepared. Then, as shown in Fig. 11A, the single domain stamping die 18 is pressed on the soften stamping film 15, to thus stamping the irregularities of the single domain stamping die 18 on the stamping film 15 (first transfer process).

As shown in Fig. 11B, a mask formed with opening portions 24 spaced at suitable intervals is disposed on the stamping film 15, and ultraviolet rays having a wavelength of from 220 to 400 nm are emitted over the mask 19 (ultraviolet ray emission process), to harden only portions of the stamping film 15 corresponding to the opening portions of the mask 19.

The mask 19 has preferably a stripe pattern in which opening portions 22 and shielding portions 24 are periodically repeated at specified intervals. The width of the opening portion 22 is determined in accordance with the size of the domain to be formed, and it is preferably 50 gm or more.

In addition, the opening portion of the mask 19 is sufficient to allow ultraviolet rays to transmit therethrough.

As shown'in Fig. 11C, the stamping film 15 is heated (second heating process). At this time, only a portion, not emitted with ultraviolet rays in the previous process, of the stamping film 15 formed on the substrate 14 of the stamping base die 34 is softened.

After that, a single domain stamping die 33 in which a plurality of irregularities repeatedly formed along the direction different from that in the single domain stamping die 18 used in the firststamping process is pressed on the stamping film 15, to stamp the irregularities of the single domain stamping die 33 on the stamping film 15 (second stamping process).

The single domain stampingdie 33 used in the second stamping process may be different from, or the same as the single domain stamping die 18. In the case where the single domain stamping die 18 is used as the single domain stamping die 33, it is changed in the direction relative to the stamping base die 34, for example, the stamping base die 34 or the single domain stamping die 18 is changed by 90 or 180 and is pressed on the stamping film 15.

By adjustment of the domain on which ultraviolet rays emitted or the number of stamping by means of the single domainstamping. die, an alignment film formed with irregularities having three or more kinds of directions or tilting angles, can be manufactured.

The whole stamping film 15 is then hardened by emission of ultraviolet rays on the whole stampIngfilm 15, to thus form the stamping base die 34 in which the stamping film 15 having irregularities extending in the two directions are formed on the substrate 14, as shown in Fig. 11E.

Next, as shown in Fig. llF, a flat stamping die 35 is pressed on the stamping film 15 of the stamping base die 34, to be stamped with the surface shape of the stamping film 15, thus manufacturing the stam ing die 35 for forming an P alignment film of a liquid crystal element as shown in Fig. 11G.

An alignment film having irregularities extending along a plurality of directions can be also formed without the above-described stamping base die.

Namely, in the method of manufacturing the stamping die for forming an alignment film of a liquid crystal element, - so - the substrate 14 of the stamping base die 34 is taken as an alignment film substrate and the stamping film is taken as an alignment- film. Referring again to Figs. 11A to 11G, this manufacturing method will be described below.

First, a thermoplastic ultraviolet ray hardening resin is flatly applied onto a substrate which is the underlayer of an alignment film, to form an alignment film preliminary layer. Next, as a first heating process, the alignment film preliminary layer is heated to be soften.

on the other hand, a single domain stamping die 18 on which a plurality of irregularities are repeatedly formed along an optional direction is separately prepared. Then, as shown in Fig. 11A, the single domain stamping die 18 is pressed on the soften alignment film preliminary layer 15, to thus stamping the irregularities of the single domain stamping die 18 on the alignment film preliminary layer 15 (first stamping process). 1 As shown in Fig. 11B, a mask formed with opening portions 24 spaced at suitable intervals is disposed on the alignment film preliminary layer 15, and ultraviolet rays are emitted over the mask 19 (ultraviolet ray emission process), to harden only portions of the alignment film preliminary layer 15 corresponding to the opening portions of the mask 19. In addition, the opening portion of the mask 19 is sufficient to allow ultraviolet rays to transmit therethrough.

As shown in Fig. 11C, the alignment film preliminary layer 15 is heated (second heating process). At this time, only a portion. not emitted with ultraviolet rays in the previous process, of the alignment film preliminary layer 15 is softened.

After that. a single domain stamping die 33 on which a plurality of irregularities repeatedly formed along the direction different from that in the single domain stamping die 18 used in the first stamping process is pressed on the alignment film preliminary layer 15, to stamping the irregularities of the single domain stampingdie 33 on the alignment film preliminary layer 15 (second stamping process).

The single domain stamping die 33 used in the second stamping process may be different from, or the same as the single domain stamping die 18. In the case where the single domainstamping die 18 is used as the single domain stamping die 33, it is changed in the direction relative to the stamping base die 34, for example, the stamping base die 34 or the single domain die 18 is changed by 90 or and is pressed for stamping.

By adjustment of the domain on which ultraviolet rays emitted or the number of stamping by means of the single domain stamping die, an alignment film preliminary layer formed with irregularities having three or more kinds of directions or tilting angles, can be manufactured.

The whole alignment film preliminary layer 15 is then hardened by emission of ultraviolet rays on the whole alignment film preliminary layer 15, to thus form the alignment film having irregularities extending in the two directions are formed on the substrate 14, as shown in Fig. 11E.

Moreover, in the stamping apparatus for stamping an irregular pattern according to the present invention, a thin die member is mounted on a press base body by way of an elastic member. Twith this stamping apparatus in the case where an irregular pattern is stamped by pressing the die member on an alignment film preliminary layer, even when the alignment film preliminary layer is tilted somewhat relative to the press base body, the elastic member ca be deformed in accordance with the tilting of the alignment film preliminary layer, with a result that the irregular pattern of the die member can be positively pressed on the whole surface of the alignment film preliminary layer.

In the case of using the die member having a thickness of from 0.001 to 0.2 mm, even when the alignment film preliminary layer has slight wavinessy irregularities or tilting due to the fine waviness, irregularities or tilting of the substrate, the elastic member and die member are positively deformed in accordance with the waviness, irregularities or tilting, and thereby the irregular pattern of the die member can be positively pressed on the whole surface of the alignment film preliminary layer. Namely. by the use of the die member having a thickness of 0.2 m or less, the elastic member and the die member can sufficiently follow the waviness, irregularities or tilting of the substrate or alignment film preliminary layer. In addition, if the elastic member has a thickness of 0.001 mm or more, it never causes any problem such as breakage in handling.

By provision of a coating layer made of gold or copper on the surface of the die member, the alignment film preliminary layer can be prevented from being stuck on the die member when an irregular pattern is stamped on the alignment film preliminary layer and then the die member is removed from the alignment film preliminary layer.

The press base body may be formed in a flat plate or roller-like shape. In the case of the flat plate-like press base body mounted with an elastic member and an die member, 54 - an irregular pattern can be stamped only by one pressing operation. On the other hand. in the case of roller-like base body, an irregular pattern can be stamped by pressing the base body while rolling it along an alignment film preliminary layer on the substrate.

The present invention will be more clearly understood by way of the following examples. However,, it is noted that the present invention is not limited thereto. Example 1 In this example. the present invention is applied to a twisted nematic liquid crystal element.

A rectangular glass substrate for a liquid crystal element, on the surface of which an electrode was formed, was prepared. on the surface of the substrate, a solution of -rbutyllactam containing 5 wt% of polyether sulfan (trademark name: PES, produced by Mitsui Toatsu) was printed to a thickness of 0. 1 g m by screen. printing, to form a solution layer. At this time, to form the solution layer, a printing squeegee was moved along the longitudinal direction of the glass substrate at a speed of about 20 cm/sec.

The substrate formed with the solution layer was prebaked for 30 seconds at 30'C, and further baked for one hour at 180'C, to dry the solution layer, thus forming an alignment film preliminary layer. Alternatively, the solution may be printed on the glass substrate which has been preliminarily heated at WC.

A columnar stamping die made of epoxy resin, on the surface of which an irregular pattern was formed as shown in Fig. 3, was set on the alignment film preliminary layer. In such a state, the alignment film preliminary layer was heated at 240C and held for 5 minutes at 24TC, and then the stamping die was pressed on the alignment film preliminary layer at a pressure of 50 kg/c& and simultaneously rolled at a moving speed of 15 m/min, to stamping the irregular pattern of the stamping die on the aiignment film preliminary layer.

An irregular pattern shown in Fig. 4 was thus stamped on the surface of the alignment film. In the irregular pat-tern, projecting and recessed portions each having an approximately triangular shape were repeatedly formed along the moving direction of the printing squeegee, that is, along the longitudinal direction of the glass substrate. The height of the projecting portion was 0.2 Am; the length of the tilting surface was 2 Am; and the interval between the projecting portions arranged in the right and left was 0.3 Am. in this example, the uniform alignment domain had a size of 30X30 Am.

Two pieces of the substrates, each being formed with 56 - such an alignment film, were superimposed in such a manner as to be separated from each other at a specified interval by way of a spacer, and TN liquid crystal (tradema k name: K-15, produced by CHISSO CORPORATION) was sealed therebetween, to prepare a liquid crystal cell.

The visual field angle of the liquid crystal element thus obtained was about 40 in the transverse direction, and about 40 in the vertical direction.

On the contrary. the visual field angle of the liquid crystal element having the same structure except that the uniform alignment domain was not provided, was about 30 - in the transverse direction, about 10 in the upward direction, and about 20 - in the downward direction.

In the previous process. the moving direction of the printing squeegee is desirable to be substantially the same as the arrangement direction of nearly triangular projecting portions; however, the moving direction of the printing squeegee is not necessarily taken as the longitudinal direction of the substrate, but it may be taken as the transverse or tilting direction.

Example 2

The solution used in Example 1 was replaced with a solution containing 2 wt% polyvinyl alcohol (trademark name: NM-14, produced by The Nippon Synthetic Chemical industry Co., Ltd.) using pure water as a solvent. The solution was applied on a substrate by spin-coating. Subsequently, the substrate formed with the solution layer was preliminarily heated for one minute at 50C and further heated for one hour at 120&C, to dry the solution, thus preparing an aliqnment film preliminary layer having a thickness similar to that in Example 1.

The substrate and a roller type stamping die shown in Fig. 2 were heated at 180C and 1OTC.. respectively, and the stamping die was pressed on the alignment film preliminary layer, and simultaneously rolled. to stamp an irregular pattern formed on the surface of the stamping die onto the alignment film preliminary layer, thus manufacturing an alignment film. Two pieces of the substrates thus obtained were superimposed in the sane manner as in Example 1, to manufacture a liquid crystal cell having a visual field angle similar to that in Example 1..

Example 3

A solution of 1,1,1,3,3,3-hexafluoro-2-propano1 containing 5% of high molecular liquid crystal (produced by Asahi Denka Kogyo) was applied onto a rectangular glass substrate similar to that used in Example 1, to form an alignment film preliminary layer. The alignment film preliminary layer was preliminarily dried for 30 seconds at WC, and further dried for one hour at 180C.

A roller type stamping die heated at 230C was pressed on the alignment film preliminary layer and simultaneously rolled along the longitudinal direction of the substrate, to stamp an irregular pattern of the stamping die onto the alignment film preliminary layer. The stamping die was formed by a method wherein a fluoro-rubber (trademark name: Bytone, produced by SUMITOMO 3M LIMITED) having a thickness of 3 m was wound by hand around the surface of a stainless steel made cylindrical core material having a diameter of 300 mm. The width of the roller portion of the stamping die was formed to be wider than the width of the substrate. The peripheral speed of the stamping die was 1 mm/sec, and the pressing force of the stamping die onto the substrate was 5 kg/cm.

In the glass substrate having the alignment film thus formed, a refractive factor nA relative to polarization in the longitudinal direction was different from a refractive factor nB relative to polarization in the transverse direction. The refractive factor nA was maximized in the plane and the refractive factor nB perpendicular to the refractive factor nA was minimized. A difference therebetween An was 2. 86X10-'.

The anisotropy of the refractive factor means that the main chains of the molecules forming the alignment film formed on the surface of the glass substrate directs in the longitudinal direction of the glass substrate. Example 4 A stamping die, used for forming an alignment film having a plurality of domains each of which has a specified alignment,. was manufactured.

First, polyvinyl cinnamate as a thermoplastic ultraviolet ray hardening resin was flatly applied onto a substrate of a stamping base die. to form g stamping film. The stamping base die was heated at 130&C, to soften the stamping film. The thickness of the stamping film was 200 nm (100 nm, even at the thinnest portion).

A single domain sta ipingdie, in which a plucality of irregularities were repeatedly formed on the surface along an optional direction, was pressed on the softened stamping film for 5 minutes at a pressure of 100 kg/cin, to stamp the irregularities of the single domain stamping die on the stamping film.

Next, a mask shown in Fig. 12 in which the pitch of opening portions was specified at 50 Am for dividing one pixel into two parts was set on the stamping film, and ultraviolet rays of 100 mw/cm2 was emitted onto the stamping film through the mask for 5 minutes using an ultraviolet ray lamp having a power of 4.5 kW and a wavelength of 375 nm,, to harden only a portion, corresponding to the opening portions of the mask, of the stamping film.

The mask was formed of a substrate made of quartz glass having a thickness of 3 mm on which shielding portions made of a cr film having a thickness of 140 = were formed.

The stamping film was heated again to soften a portion of the stamping film not emitted with ultraviolet rays, and the above-described single domain stamping die was rotated by 180 and pressed on the stamping film. Ultraviolet rays were then emitted over the stamping film to harden the whole stamping film. Subsequently, the stamping base die was pressed on a flat stampingdie, to stamp the surface shape of the ztamping base die onto the flat stamping die, thus manufacturing the stamping die for forming an alignment film for a liquid crystal element.

Differently from the above-described method of manufacturing a stampingdie for forming an alignment film from the stamping base die prepared using a single domain stamping die, a stampingdie for forming an alignment film can be directly manufactured from a single domain stamping die without a stamping base die.

Example 5 An alignment film having a plurality of domains each of which has a specified alignment was manufactured.

First, polyvinyl cinnamate as a thermoplastic ultraviolet ray hardening resin was flatly applied onto a substrate, to form an alignment film preliminary film. The alignment film preliminary layer was heated at 130&C, to soften the alignment film preliminary film. The thickness of the stamping film was 200 nm (100 rim, even at the thinnest portion).

A single domain stamping die, in which a plurality of irregularities were repeatedly formed on the surface along an optional direction, was pressed on the softened aiignment film preliminary layer for 5 minutes at a pressure of 100 kg/cm2, to stamp the irregularities of the single domain stamping die on the alIgnment film preliminary layer.

A inask shown in rig. 12 in which the pitch of opening portions was specified at 50 gm for dividing one pixel into two parts was set on the alignment film preliminary layer, and ultraviolet rays of 100 mw/cm2 was emitted onto the alignment film preliminary layer through the mask for 5 minutes using an ultraviolet ray lamp having a power of 4.5 kW and a wavelength of 375 nm, to harden only a portion, corresponding to the opening portions of the mask, of the alignment film preliminary layer.

The mask was formed of a substrate made of quartz glass having a thickness of 3 mm on which shielding portions made of a cr film having a thickness of 140 nm were formed.

The alignment film preliminary layer was heated again to soften a portion of the alignment film preliminary layer not emitted with ultraviolet rays, and the abovedescribed single domain stamping die was rotated by 180 and pressed on the alignment film preliminary layer. After that, ultraviolet rays were emitted over the alignment film preliminary layer to harden the whole alignment film preliminary layer, thus forming the alignment film for a liquid crystal element.

Example 6

Fig. 17 shows an example of a stamping apparatus of the P.casent invention. A stamping apparatus 110 includes a press Substrate 111, a sheet-like elastic member 112 mounted on the lower surface of the press substrate 111, and a sheet-like die member 113 mounted on the.lower surface of the elastic member 112.

The press substrate 111 is made of a metal material having a high rigidity, and the lower surface thereof is accurately ground by a grinding means. The surface roughness of the press substrate 111 is preferably adjusted at, for example, about 10 gm.

The elastic member 112 is formed of a resin layer having a thickness of from 0.8 to several mm. The resin layer is preferably made of silicon rubber.

The die member 113 is made of nickel, gold or copper, and has a thickness preferably in the range of from 0.01 to 0.2 mm. In the die member 113, an irregular pattern is formed on the surface of the flat base body. The portion of the irregular pattern on the surface of the die member 113 is covered with a film layer made of gold.. gold alloy, copper or copper alloy. The film layer is formed on the irregular pattern to a thickness of from 0.1 to 0.5 iúm by vapor deposition or sputtering.

In Fig. 17, reference numeral 115 indicates a transparent substrate made of glass; and 116 is an a!-gnment film preliminary layer made o aromatic polyamide covering the substrate 115. In the drawing, the waviness of the substrate 115 is emphasized; however, the camber and the irregularities of the substrate 115 are specified to be in the order of gm or less.

The irregular pattern is stamped on the alignment film preliminary layer 116 in the following procedure. The die member 113 of the stamping apparatus 110 is set on the alignment film preliminary layer 116 and is pressed thereon as shown in Fig. 18.

in this case, even when the waviness or irregularities are generated somewhat on the substrate 115. they can be absorbed by the deformation of the die member 113 and the elastic member 112 as shown in Fig. 18. This is because the die member 113 is thin and excellent in flexibility, and the elastic member 112 can be elastically deformed. As a consequence, the die member 113 can be positively pressed on the alignment film preliminary layer 116. At this time, the pressing temperature is preferably in the range of from 100 to 200C and the pressing force is preferably in the range of from 50 to 100 kg/cm.

The irregular pattern corresponding to that of the die member 113 is stamped on the alignment film preliminary layer 11. The alignment film preliminary layer 116 is thus taken as an alignment film.

After the stamping of the irregular pattern, the die member 113 is separated from the alignment film. At this time, since the covering layer,made of gold, gold alloy, copper or copper alloy is present on the surface of the die member 113, part of the alignment film is difficult to be stuck on the die member 113, and to be peeled to the die member 113 side. The irregular pattern can be thus positively stamped. Namely, the alignment film preliminary layer 116 is difficult to be stuck on the covering layer made of gold or copper formed on the surface of the die member 113 due to a difference in the surface energy between aromatic polyamide constituting the alignment film preliminary layer 116 and gold or copper.

Thus, it is possible to manufacture an alignment film stamped with the irregular pattern without harming part of the alignment film preliminary layer.

As described above, gold or copper is difficult to be stuck on the alignment film preliminary layer 116 on the basis of a difference in the surface energy between the alignment film preliminary layer and gold or copper. and the same effect can be obtained when gold or copper is replaced with a gold alloy or copper alloy added with another element such as nickel.

Example 7

Figs. 19 and 20 show another stamping apparatus of the present invention. A transfer apparatus 120 includes a roller (press base body) 121, a flat elastic body 122 provided separately from the roller 121, and a die member 123 integrated with the lower surface of the elastic member 122. The elastic member 122 has the same structure as that of the elastic member 112 of the previous example, and the die member 123 has the same structure as that of the die member 113 in the previous example.

In this example, as shown in Fig. 19, the die member 113 is placed on an alignment film preliminary layer 116 of the substrate 115, and in such a state, the roller 121 is pressed on the elastic member 122 and is simultaneously rolled from one side of the substrate 115 to the other side.

with this operation, the irregular pattern of the die member 123 is stamped OM the alignment film preliminary layer 116 while the elastic member 122 and the die member 123 are respectively deformed in accordance with the waviness and the irregularities of the substrate 115.

In the case using the transfer apparatus 120, the same effect as in Example 6 can be obtained. Example 8 Figs. 21 and 22 show a further stamping apparatus of the present invention. A stamping apparatus 130 includes a roller (press base body) 131, a sheet-like elastic member 122 stuck on the surface of the roller 131, and a die member 133 stuck on the surface of the elastic member 132. The elastic member 132 has the same structure as that of the elastic member 112 in the previous example, and the die member 133 has the same structure as that of the die member 113 in the previous example.

In this apparatus, as shown in Fig. 22, the roller 131 is placed on an alignment film preliminary layer 116 of the substrate 115, and in such a state, the elastic member 132 on the surface of the roller is pressed on the alignment film preliminary layer 116 at a specified pressure, and is simultaneously rolled from one side of the substrate 115 to the other side. With this operation, the irregular pattern of the die member 133 is stamped onto the alignment film preliminary layer 116 while the elastic member 132 and the die member 133 are respectively deformed in accordance with the camber and irregularities of the substrate 115. In the case of using the stamping apparatus 130, the same effect as in

Example 6 can be obtained.

Fig. 23 shows one example of an alignment film having the irregular pattern formed using each of the stamping apparatuses in Examples 6, 7 and 8. The alignment film 140 has an irregular pattern desirable to specify a pretilt angle of liquid cz-7stal.

The irregular pattern in this example is formed of the collection of a number of triangular projecting portions 141 along the first and second directions shown by the arrows in the figure. A pitch P1 of the irregularities along the first direction is set to be shorter than a pitch P2 of the irregularities along the second direction. For example, the pitch P, is 3.0 gm or less, and the pitch P2 is 50 gm or less. The height (depth) d, of the projecting portion 141 is, for examDle 0.5 gm or less.

Test Example 1 A stamping apparatus used in this test example has a structure shown in Fig. 17, that is, it is integrally provided with a flat substrate made of tool steel (specified by JIS SK4), a sheet-like elastic member made of silicon rubber having a thickness of 0.8 mm, and a die member made of nickel. An irregular pattern stamping test was carried out using this stamping apparatus. An irregular pattern was stamped on an alignment film preliminary layer made of aromatic polyamide having a thickness of 0.2 Am formed on a glass substrate having a thickness of 1.1 mm. The stamping pressure was 100 kg/cm. The irregular pattern was as shown in Fig. 23, wherein the pitch in the first direction was 0.3 Am, the pitch in the second direction was 2 Am, and the height of the projecting portion was 0.2 Am.

Eight kinds of stamping apparatuses were experimentally manufactured using eight kinds.of die members having thicknesses of 3 m, lmm, 0.5 mm, 0.2 mm, 0.05 mm, 0.015 mm, 0.005 mm and 0.001 mm. using each of these stamping apparatuses, an irregular pattern stamping test was carried out. A gold evaporation film having a thickness of 0.1 Am was formed on the surface having the irregular pattern. In addition, a die member having a thickness of 0.001 mm or less was intended to be manufactured; however, it could not be manufactured because of being poor in strength.

The alignment film thus obtained was subjected to an interference light measurement testl and to stamp ratio measurement test. The results are shown in Table 1. In the interference light measurement test. the presence or absence of the interference light generated when light is emitted onto the alignment film is visually observed. The results are shown in terms of the area. One example is typically shown in Fig. 24A. In Fig. 24A, the interference light is recognized in a domain A where stamping is performed; and the interference light is not recognized in a domain B where stamping is not performed.

In the transfer ratio measurement test, the ratio of the depth of a groove of the recessed portion in the irregular pattern of a die member to the depth of a groove of the irregular pattern of the alignment pattern is measured as the stamping ratio.

The depth of the groove is measured by a method wherein the average value in a plane as the depth of the groove is measured by AFM (Atomic Force microscope).

Table 1 thickness of die domain of interference starnping ratio member (mm) light (%) 3 < 30 < 30 1 < so < 50 0.5 < 50 < 50 0.2 < 100 < 90 0.05 < 100 < 90 0.03 < 100 < 90 0.015 < 100 < 95 0.005 < 100 < 95 0.001 < 100 < 95 As is apparent from Table 1, in the case of using a die member having a thickness of 0.2 mm, the interference light generating domain is nearly 100%, that is. the stamping is perfectly performed; and in this case, the stamping ratio is as high as about 90%. Moreover, in the case of using a die member having a thickness of 0.015 mm or less, the stamping ratio is 95%.

Test Example 2 Next, three kinds of stamping dies, in each of which a die member had a thickness of 0.05 mm and the covering layer formed on the surface of the die member was made of either of gold, copper or nickel, were experimentally manufactured. The stamping of an irregular pattern was performed using each of the die members. It was observed whether or not a separated alignment film preliminary layer was stuck on the surface of the die member.

As a result, in the case of the nickel covering layer, as shown in Fig. 24B, a separation portion having a diameter of from 0.5 to 3 m was stuck in a dotted manner. It was revealed that the sticking domain with the alignment film was 30% or less. In addition, in thestamping apparatus using a die member formed with a gold covering layer or a copper covering layer. there was not recognized a phenomenon in which the alignment film preliminary layer was stuck on the die member.

Claims

1. A liquid crystal element comprising: a pair of substrates disposed so as to face to each other, and having respective alignment films on the facing surfaces thereof; and liquid crystal held between said substrates; wherein a surface shape of said alignment film formed on at least one of said substrates is formed by pressing of a die, and said alignment film formed with the surface shape by pressing of the die has a plurality of uniform alignment domains which are different from each other in the emergent direction or emergent magnitude of a pretilt angle of liquid crystal within an effective display plane.

2. A liquid crystal element according to claim 1, wherein said alignment film formed on one of said substrates and having a plurality of said uniform alignment domains has two directional uniform alignment domains in which the emergent directions of the pretilt angle of liquid crystal are approximately parallel to each other, and said alignment film formed on the other of said substrates has a pretilt angle lower than said pretilt angle in one of said substrates.

3. A liquid crystal element according to claim 1 or 2. wherein the surface shape of said alignment film is formed by collection of a plurality of projecting portions having tilting surfaces, and said tilting surfaces of said projecting portions function as a means of adjusting the pretilt angle of liquid crystal.

4. A liquid crystal element according to any of claims 1 to 3, one uniform alignment domain having an emergent direction or emergent magnitude of a pretilt angle of liquid crystal is formed by the collection of first projecting portions having tilting surfaces extending at a tilting angle, and the other uniform alignment domain having an emergent direction or emergent magnitude of a pretilt angle different from that in said one uniform alignment domain is formed by collection of a plurality of second projecting portions having tilting surfaces extending at an angle different from that of said ti.lting surfaces of said first projecting portions.

5. A liquid crystal element according to any of claims 1 to 4, wherein the surface shape of an alignment film is formed by collection of projecting portions having tilting surfaces, and the tilting angle of the tilting surfaces of said projecting portions formed on the surface of said alignment film is specified at 6 or more.

6. A method of manufacturing a liquid crystal element having liquid crystal held between a pair of substrates. said substrates being disposed so as to face to each other and having respective alignment films on the facing surfaces thereof; comprising: an alignment 'film preliminary layer forming process of forming an alignment film preliminary layer on the surface of each of said substrates; and a shape imparting process of pressing a die capable of forming a plurality of uniform alignment domains different from each other in an emergent direction or emergent magnitude of a pretilt angle of liquid crystal within an effective display plane on the surface of said substrate, on the surface of at least one of said alignment film preliminary layer.

7. A method of manufacturing a liquid crystal element having liquid crystal held between a pair of substrates, said substrates being disposed so as to face to each other and having respective alignment films on the facing surfaces thereof; comprising: an alignment film preliminary layer forming process of forming an alignment film preliminary layer on the surface of each of said substrates; and a first shape imparting process of pressing a die capable of formIng uniform aiignment domains nearly equal to each other in an emergent direction or emergent magnitude of a pretilt angle of liquid crystal within an effective display plane on the surface of said substrate, on the surface of at least one of said alignment film preliminary layer; and a second shape imparting process of pressing a die capable of forming uniform alignment. domains different in the emergent direction of the pretilt angle from those obtained in said first shape forming process, on the surface of said alignment film preliminary layer.

8. A method of manufacturing a liquid crystal element according to claim 6 or 7, which further comprises a shape imparting process of pressing said die on one of said alignment film preliminary layers, and a process of pressing an approximately cylindrical roller formed at least on the surface with an elastic,body on the other of said alignment film preliminary layers.

9. A method of manufacturing a liquid crystal element according to any of claim 6 to 8, wherein said uniform alignment domains are formed using a stamping die in which a plurality of projecting portions having tilting surfaces are formed on the surface and the tilting angle of said tilting surfaces of said projecting portions is specified at 6 or more.

10. A method of manufacturing a liquid crystal element according to any of claims 6 to 9. wherein said shape imparting process is carried out using a die on the surface of which a plurality of first portions each forming one uniform alignment domain and a plurality of second portions each forming the other uniform alignment domain are formed, said first portion being constituted of collection of a plurality of projecting portions with tilting surfaces having the same tilting direction and the same tilting angle, and said second portion being constituted of a plurality of projecting portions with tilting surfaces having a tilting direction.and a tilting angle different from said tilting direction and said tilting angle of said first portion.

11. A stamping die for forming an alignment film for a liquid crystal element, which is pressed on the surface of a resin made alignment film preliminary layer formed on a substrate for a liquid crystal element for forming a plurality of projecting portions on the surface of said alignment film preliminary layer, comprising: irregularities repeatedly formed on the surface of said stamping,die along a first direction; and irregularities repeatedly formed on the surface of said stamping die along a second direction crossing said first direction, wherein the tilting direction of said tilting surfaces formed by said irregularities are specified for each of a plurality of divided domains formed on the surface of said stamping die.

12. Astamping die for forming an alignment film for a liquid crystal element according to claim 11, wherein the tilting angle of said tilting surfaces of said projecting portions formed on the surface of said stamping die is specified at 6 or more.

13. Astamping die for forming an alignment film for a liquid crystal element according to claim 11 or 12, wherein said divided domain of said stampingdie is equivalent to one of said projecting portions formed on said stamp.ng die.

14. A method of manufacturing a stamping die for forming an alignment film for a liquid crystal element comprising: a first heating process.of heating A stamping film made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a firststamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along an optional direction, on said stamping film; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals, and emitting ultraviolet rays to said stamping film through said mask; a second heating process of heating said stamping film after said ultraviolet ray emitting process; a second stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process, on said stamping film; and a process of pressing said stamping die on said stamping film after said second stamping process, thereby stamping the surface shape of said stamping film on said stainping die.

15. A method of forming an alignment film for a liquid crystal element, comprising:

a first heating process.of heating an alignment film preliminary layer made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a first stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along an optional direction, on said alignment film preliminary layer; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals, and emitting ultraviolet rays to said alignment film preliminary layer through said mask; a second heating process of heating said alignment film preliminary layer after said ultraviolet ray emitting process; and a second stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process, on said alignment film preliminary layer.

16. A method of manufacturing a stamping die for forming an alignment film for a liquid crystal element, comprising: a first heating process of heating astamping film made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a first stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along an optional direction, on said stamping film; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals, and emitting ultraviolet rays to said stamping film through said mask; a second heating process of heating said stamping film after said ultraviolet ray emitting process; and a second stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process, on said film.

17. A method of manufacturing a stamping die for forming an alignment film for a liquid crystal element. comprising:

a first heating process of heating a stamping film made of a thermoplastic ultraviolet ray hardening resin formed on a substrate; a first stamping process of pressing, a single domain stamping die on the surface of which a plurality of irrecrularities are repeatedly formed along an optional direction, on said stamping film; a ultraviolet ray emitting process of disposing a mask formed with opening portions at suitable intervals,, and emitting ultraviolet rays to said stamping film through said mask; a second heating process of heating said stamping film after said ultraviolet ray emitting process; and a second stamping process of pressing, a single domain stamping die on the surface of which a plurality of irregularities are repeatedly formed along a direction different from said optional direction in said first stamping process, on said stamping film; wherein the surface shape is formed on said stamping die by electro-casting using said stamping film after said stamping process as an original template.

18. A stamping apparatus used for pressing a die member having an irregular pattern on an alignment film preliminary layer on a substrate thereby stamping the irregular pattern on the upper surface of said alignment film preliminary layer, comprising:

19. A stamping apparatus according to claim 18, wherein said elastic member is mounted on the surface of said press base body, and said die member is mounted on the surface of said elastic member.

20. A stamping apparatus for forming an irregular pattern on an alignment film according to claim 18 or 19, wherein said press base body is formed in a flat shape.

21. A stamping apparatus for forming an irregular pattern on an alignment film according to 18 or 19, wherein said press base body is formed in a roller shape.

22. A stamping apparatus according to any of claims 18 to 21, wherein said die member is formed to a thickness in the range of from 0.001 m to 0.2 m.

23. A stamping apparatus according to any of claims 18 to 22, wherein a coating layer made of gold, gold alloy, copper or copper alloy is formed on the surface of said die member.

24. A liquid crystal element substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

25. A method of manufacturing a liquid crystal element substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

26. A stamping die substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

27. A method of manufacturing a stamping die substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

28. A method of forming an alignment film for a liquid crystal element substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

29. A stamping apparatus for forming a pattern on an alignment film substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.