JPH11174456A - Substrate for alignment division and its production as well as liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widen the visual field angle of a liquid crystal display element by varying the pre-tilt angle of liquid crystal molecules within one pixel by means with which production is easy. SOLUTION: Ground surface layers 22 each having a triangular shape in section consisting of a resin are formed in each of respective pixel regions on the surface of a transparent substrate 2a. Transparent electrodes 23 of a uniform thickness are formed on these ground surface layers 22. Alignment layers 24 are formed on the transparent substrate 2a from above these transparent electrodes 23 and are subjected to a rubbing treatment. The regions varying in the inclination of the alignment layers 24 exist within one pixel and, therefore, the alignment directions of the liquid crystal molecules are varied with each of the respective regions and the visual field angle of the liquid crystal element is widened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for alignment division, a method for manufacturing the same, and a liquid crystal display device. Specifically, the present invention relates to a technique for increasing the viewing angle of a liquid crystal display device.

[0002]

2. Description of the Related Art (First Conventional Example) A liquid crystal display device is a device in which liquid crystal is sealed between a pair of transparent substrates on which a transparent electrode and an alignment film are formed. For example, a TN (twisted nematic) type is used. Conventionally, a liquid crystal display element has a structure as shown in FIG.

In this liquid crystal display element 1, a transparent substrate 2a, 2b made of a thin glass plate, a plastic film, or the like is joined via a frame-shaped sealing material at a peripheral portion thereof, and a liquid crystal is provided between the two transparent substrates 2a, 2b. The transparent insulating films 4a and 4b are formed on the opposing surfaces of the transparent substrates 2a and 2b, respectively.
The transparent electrodes 5a and 5b are formed on the substrate b. In addition,
In a simple matrix type liquid crystal display device, a transparent electrode formed on one transparent substrate serves as a scanning electrode, and a transparent electrode formed on the other transparent substrate serves as a signal electrode.

On the electrode forming surfaces of the transparent substrates 2a and 2b, a horizontal alignment material such as polyimide is applied and then dried and hardened to form horizontal alignment films 6a and 6b. Each of the alignment films 6a and 6b is a rubbed film in which the film surface is rubbed with a cloth so that the liquid crystal molecules 3a are aligned in one direction. It is almost 90 ° off.

As shown in FIG. 2, the liquid crystal molecules 3a sealed between the transparent substrates 2a and 2b are separated by the alignment films 6a and 6b of the transparent substrates 2a and 2b.
The transparent substrates 2a and 2b are oriented in a predetermined direction in a pretilt state (pretilt angle φ) that is appropriately inclined with respect to the film surfaces of the films a and 6b, and are twisted at a twist angle of approximately 90 ° between the transparent substrates 2a and 2b.

[0006] Polarizing plates 7a and 7b are disposed on the outer surfaces of the transparent substrates 2a and 2b, respectively. For example, in a TN liquid crystal display element of a positive display type, the transmission axes of a pair of polarizing plates are substantially orthogonal to each other.

The liquid crystal display element 1 has two transparent substrates 2a,
An image is displayed by controlling the transmission of light by applying a voltage between the transparent electrodes 5a and 5b of 2b. The liquid crystal molecules 3a sealed between the transparent substrates 2a and 2b are separated by the alignment films 6a and 6b of the transparent substrates 2a and 2b.
The transparent substrates 2a and 2b are oriented in a predetermined direction in a pretilt state that is appropriately inclined with respect to the film surfaces of the transparent substrates 2a and 6b, and are twisted at a twist angle of about 90 ° between the transparent substrates 2a and 2b. Therefore, in a state where no voltage is applied, that is, in a state where the liquid crystal molecules 3a are twisted, the linearly polarized light that has entered the liquid crystal layer 3 through one polarizing plate 7a is rotated by about 90 ° in the polarization direction, and the other is polarized. The light enters the polarizing plate 7b and is
, The pixel is in a bright display state. On the other hand, in a voltage applied state, that is, in a state where the liquid crystal molecules 3a are arranged to rise almost vertically, the linearly polarized light is
The light enters the other polarizing plate 7b in the polarization state at the time of incidence without being affected by the optical rotation effect of the above, and is absorbed by this polarizing plate 7b, so that the pixel is in a dark display state.

(Problem of the First Conventional Example) Such a liquid crystal display element has an advantage of low power consumption because it displays external light using (natural light or backlight light). However, on the other hand, there is a disadvantage that an observation angle (hereinafter, referred to as a viewing angle) (measured obliquely from the front of the display surface) at which the display can be viewed with good display color and contrast is narrow. This is because, in the liquid crystal display device, since liquid crystal molecules have anisotropy of refractive index (also referred to as birefringence), a phenomenon occurs in which display color and contrast change depending on an angle at which the liquid crystal display device is observed.

(Second Conventional Example) In order to increase the viewing angle of a liquid crystal display device, various devices have been devised so far, but the alignment state of liquid crystal molecules must be reduced to at least two in a single pixel. One of these methods is a method called orientation division in which a plurality of viewing angle states are mixed. This is because two regions having different alignment states existing in the same pixel have different viewing angles, so that the total viewing angle in the pixel is widened.

FIG. 3 shows the structure of a liquid crystal display device using such an orientation division technique (Japanese Patent Laid-Open No. Hei 6-289398). In this liquid crystal display element 8, one transparent electrode 9a is formed in a triangular cross section, and one side of the transparent electrode 9a is inclined in the direction opposite to the other side in a single pixel. Therefore, the alignment film 1 applied on the transparent electrode 9a
0a is also inclined in different directions for each side within a single pixel. The inclined surfaces having different inclination directions in the alignment film 10a are rubbed, for example, in opposite directions.

FIGS. 4 and 5 illustrate the principle of widening the viewing angle of the liquid crystal display element 8 with such a structure. In the liquid crystal molecules 3a having the refractive index anisotropy, as shown in FIG. 4, when the viewing direction (viewing angle) differs with respect to the liquid crystal molecules 3a, the apparent refractive indices n1 and n2 (n1 ≠ n2) also differ. Therefore, if the directions of the liquid crystal molecules 3a in the liquid crystal display element 8 are different, even if the liquid crystal display element 8 is viewed from the same direction, depending on the direction of the liquid crystal molecules 3a.
Have different refractive indices (that is, the refractive index distribution changes),
The viewing direction of the liquid crystal display element 8 that is easily seen changes for each of the liquid crystal molecules 3a facing different directions.

Here, as shown in FIG. 5, the alignment film 10a
Is inclined in two directions for each pixel, the liquid crystal molecules 3
a is oriented at the total pretilt angle obtained by adding the surface tilt angle of the alignment film 10a to the pretilt angle given by the alignment film 10a, so that the liquid crystal molecules 3a are aligned in different pretilt states within one pixel, and the twist alignment state Are different 2
There are two areas. Since the viewing angle of the liquid crystal display element 8 is determined by the twist alignment state of the liquid crystal molecules 3a between the transparent substrates 2a and 2b, the two regions in a single pixel have different viewing directions and have different viewing directions. The directions are combined, so that the viewing angle of the liquid crystal display element 8 is widened as a whole.

In order to form the transparent electrode 9a having a variable thickness, as shown in FIGS. 6A, 6B, and 6C, the transparent electrode 9a is formed by a vacuum deposition method, a sputtering method, or the like. That is, as shown in FIG. 6A, the same number of slits 12 as the number of the transparent electrodes 9a formed on the transparent substrate 2a are formed on the transparent substrate 9a by the mask 11 having the same pitch (pixel pitch). A transparent electrode material 13 such as ITO is deposited on the transparent substrate 2a through the slit 12 while facing the mask 2a and moving the mask 11 in parallel in a direction perpendicular to the length direction of the slit 12. At this time,
The mask 11 is moved by the pixel pitch, and the moving speed is reduced in the first half and accelerated in the second half. When the transparent electrode material 13 is deposited in this manner, a transparent electrode film having a triangular wave-shaped cross section as shown in FIG.
This is patterned by a photolithography method to obtain a transparent electrode 9 having a desired shape as shown in FIG.
Obtain a.

Alternatively, after a transparent electrode material 13 such as ITO is deposited flat and thick on the surface of the transparent substrate 2a,
In some cases, the transparent electrode material 13 is etched by a photolithography method to obtain a transparent electrode 9a having a shape as shown in FIG.

(Problems of the second conventional example) In the liquid crystal display element 8 using the alignment division method as described above, a wide viewing angle can be achieved, but the liquid crystal display element 8 needs a base for tilting the alignment film 10a. For example, forming a transparent electrode 9a having a triangular cross-section requires a complicated work process, and the moving speed of the mask 11 needs to be slow to obtain accuracy. Transparent substrate 2a formed
There is a problem that it takes too much time to manufacture each of them, and it is also difficult to obtain accuracy. Also, since it takes time to form the transparent electrode 9a on the transparent substrate 2a,
The cost of the transparent substrate 2a on which the transparent electrode 9a is formed and the liquid crystal display element 8 are also high.

Further, since the desired transparent electrode 9a is obtained by etching the transparent electrode material 13 formed on the transparent substrate 2a for each transparent substrate 2a, the variation in the shape of the transparent electrode due to the etching increases (etching). For example, it is important that the atmosphere such as temperature and gas is uniform, which is not suitable for processing a fine concavo-convex pattern uniformly over a large area), which may affect the characteristics of the liquid crystal display element. there were.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a liquid crystal display device having a wide viewing angle and which can be manufactured efficiently. And a substrate for the alignment division. Another object of the present invention is to provide a method for manufacturing a substrate for the orientation division.

[0018]

DISCLOSURE OF THE INVENTION In the substrate for orientation division according to the present invention, in each pixel region on the surface of the transparent substrate, a base layer having irregularities on the surface is formed for each pixel region. It is characterized in that a transparent electrode is formed on the whole. In this case, the underlayer itself has irregularities.

Another substrate for orientation division according to the present invention is:
In each pixel region on the surface of the transparent substrate, a base layer is formed on a part of each pixel region, and a transparent electrode is formed on the entire pixel region from above the base layer. In this case, irregularities are formed on the surface of the transparent substrate by the portion where the underlayer is formed and the portion where the underlayer is not formed.

Here, "each pixel region" means, for a color liquid crystal, each pixel region of red (R), green (G) and blue (B). Further, a group of red (R), green (G), and blue (B) may be defined as one pixel region (picture element).

If an alignment film is formed on the surface of such an alignment dividing substrate, a liquid crystal display element can be manufactured by using one or both substrates for enclosing the liquid crystal layer with the liquid crystal layer interposed therebetween. Can be. That is, the liquid crystal display element of the present invention is one in which a base layer having irregularities on at least one transparent substrate surface is formed for each pixel region, and a transparent electrode is formed over the entire pixel region from above the base layer. is there.
Further, another liquid crystal display element of the present invention is one in which a base layer is formed on a part of each pixel region of at least one transparent substrate, and a transparent electrode is formed on the entire pixel region from above the base layer. It is.

When an alignment film is formed on the surface of such an alignment divided substrate, the surface of the transparent substrate is not flat, so that the inclination angle of the alignment film surface changes within one pixel, or the height of the alignment film surface increases. Or change. When the surface tilt angle of the alignment film changes within one pixel, the surface tilt angle of the alignment film is added to the pretilt angle of the liquid crystal molecules, so that the pretilt angle of the liquid crystal molecules becomes uneven within one pixel. As a result, when used in a liquid crystal display device, the viewing angle can be widened. Further, when the height of the surface of the alignment film changes in one pixel, the rubbing amount of the liquid crystal molecule changes, so that the pretilt angle of the liquid crystal molecule becomes non-uniform in one pixel. When used in a liquid crystal display device, the viewing angle can be widened.

Further, since the pretilt angles of the liquid crystal molecules are non-uniform in each pixel, the image is uneven due to the image area of the liquid crystal display element, unlike the pretilt angle of each pixel which is non-uniform. There is no danger.

Further, by changing the shape of the underlayer, the surface of the transparent electrode or the alignment film can be freely changed even if the transparent electrode has a uniform thickness. Moreover, since the transparent electrode may be formed to have a uniform thickness, the manufacturing process of the transparent electrode does not become complicated as in the conventional example, which is advantageous in terms of cost.

For the substrate for alignment division, a photocurable resin is supplied on a transparent substrate, and the unevenness is transferred to the photocurable resin by a stamper having projections and depressions. Then, the photocurable resin is irradiated with light. It can be manufactured by removing the stamper from the irregularities formed by the cured photocurable resin, and then forming a transparent electrode in each pixel region from the irregularities.

When the unevenness is transferred to the surface of the transparent substrate by the stamper using the photocurable resin as described above, curing time after molding is not required unlike the case of using the thermosetting resin, and the alignment division can be efficiently performed. Substrate can be manufactured,
Cost can be reduced. In addition, an underlayer having a complicated shape and a transparent electrode having a complicated surface shape can be easily produced.

[0027]

(First Embodiment) FIG. 7 is a sectional view of a TN type liquid crystal display element 21 according to one embodiment of the present invention. In the liquid crystal display element 21, of the pair of transparent substrates 2a and 2b sealing with the liquid crystal layer 3 interposed therebetween,
One of the transparent substrates 2a has a function of dividing the orientation.

First, the substrate 25 for a liquid crystal display element having a function of dividing the orientation will be described. This alignment division substrate 2
As shown in FIG. 8, a base layer 22 (1) having a triangular cross section (roof shape) composed of two inclined surfaces having different inclinations is formed on a surface of a transparent substrate 2a made of a thin glass plate, a plastic film, or the like, as shown in FIG. 9 are formed for each pixel pitch, and a transparent electrode 23 having a uniform thickness is formed on each of the underlayers 22. This underlayer 22
Is formed of a transparent plastic material.
The base layer 22 and the transparent electrode 23 are provided corresponding to the display pixels. In a single pixel, the surface of the transparent electrode 23 has two different inclinations, and the adjacent base layer 22 and the transparent electrode 23 have different inclinations. 23 are electrically separated from each other.

After receiving the supply of such an orientation division substrate 25 from a transparent substrate maker or the like, the orientation division substrate 25
Polyimide, polyamide, on the surface of the transparent electrode 23 side of
An alignment film 24 made of an organic polymer selected from the group consisting of polyamideimide, polystyrene, epoxy acrylate, and polyurethane is uniformly applied, and the surface of the alignment film 24 is cleaned with a cloth or a brush as shown by arrows in FIG. Rub in the direction. Of course, when rubbing the surface of the alignment film 24, rubbing may be performed in the opposite direction on inclined surfaces having different inclination directions. Similarly, a transparent substrate 2b on which a flat transparent electrode 5b is formed (a conventional transparent substrate)
Also, an orientation film 6b is applied from above the transparent electrode 5b and rubbed in one direction.

Next, the pair of transparent substrates 2a and 2b are opposed to each other so that the rubbing directions are shifted from each other by approximately 90 ° and the transparent substrates 2a and 2b are separated from each other by a frame-shaped sealing material at the peripheral portion. And the liquid crystal layer 3 is sealed between the transparent substrates 2a and 2b. Further, polarizers 7a, 7b are provided on the outer surfaces of the transparent substrates 2a, 2b, respectively.
Is arranged. For example, in a positive display type TN type liquid crystal display device, the polarizing plates 7a and 7b are arranged so that transmission axes are substantially orthogonal to each other.

Even in the liquid crystal display element 21 having such a structure, the molecules 3a of the liquid crystal sealed between the transparent substrates 2a and 2b are almost 90 ° by the alignment films 24 and 6b of the transparent substrates 2a and 2b. Twist arrangement at the twist angle of
In a single pixel, the liquid crystal display element 21 is aligned at a different pretilt angle (a total pretilt angle obtained by adding the surface tilt angle of the alignment film 24) to each of the inclined surfaces having different tilt angles of the alignment film 24. The liquid crystal display element 21 has different viewing directions within one pixel, and the viewing angle of the liquid crystal display element 21 is widened as a whole.

(Method of Manufacturing Oriented Split Substrate) Next, FIG.
A method for manufacturing the alignment division substrate 25 shown in FIG. The alignment division substrate 25 is a so-called 2P (Photo-Polymeri) using an ultraviolet curable resin 26 which cures when irradiated with ultraviolet light.
zation) method. As shown in FIGS. 11 (a) and 11 (b), after supplying a transparent ultraviolet ray curable resin 26 having fluidity onto the transparent substrate 2a, the ultraviolet ray curable resin 26 is supplied.
The stamper 27 is lowered toward the transparent substrate 2a from above [FIG. 11 (c)]. On the lower surface of the stamper 27, a concave (inverted) shape 28 matching the shape of the underlayer 22 is formed at the same pitch as the pixel pitch. This stamper 27
Is pressed sufficiently against the transparent substrate 2a to sandwich the ultraviolet curable resin 26 between the stamper 27 and the transparent substrate 2a, and the concave mold 28 of the stamper 27 is filled with the ultraviolet curable resin 26. Ultraviolet light (U
V light) (FIG. 11D). The ultraviolet-curable resin 26 irradiated with ultraviolet light undergoes a curing reaction when exposed to ultraviolet light, and is cured. Therefore, the concave mold 28 of the stamper 27 is transfer-molded to the ultraviolet-curable resin 26 and is transparent by the cured ultraviolet-curable resin 26. An underlayer 22 is formed on the substrate 2a [FIG. 11 (e)]. When the underlayer 22 is thus formed, a transparent electrode material 29 such as ITO is uniformly deposited thereon by a vacuum evaporation method, a sputtering method, or the like [FIG.
(F)]. Next, the film of the transparent electrode material 29 is
By patterning by etching or the like according to the pattern of the above, and by separating the transparent electrode material 29 for each pixel,
The transparent electrode 23 having two inclined surfaces can be formed in one pixel [FIG. 11 (g)].

When the orientation division substrate 25 is manufactured in this manner, the underlayer 22 can be easily formed on the transparent substrate 2a using the stamper 27, and the underlayer 22 is formed by irradiating ultraviolet rays. Is hardened, the curing time for curing the resin is not required, the alignment division substrate 25 can be manufactured in a simple process and in a short time, and is suitable for mass production of the alignment division substrate 25. .

The reason will be described in detail below. According to the 2P method, the base layer 22 having a complicated shape can be easily formed by transferring the mold of the stamper 27 to the ultraviolet curable resin 26, and the base layer having a complicated shape (for example, FIG. By depositing the transparent electrode material 29 having a uniform thickness on the transparent electrode 23 shown in FIGS. 23 to 25, the transparent electrode 23 having a complicated surface shape can be easily manufactured. In particular, if a relatively low-viscosity ultraviolet-curable resin 26 is used and pressed with a stamper 27 and then cured by irradiating ultraviolet rays, the mold of the stamper 27 can be transferred with high accuracy, and accurate duplication can be achieved. Can be done in large quantities. Further, in the 2P method, the base layer 22 is formed only by collectively exposing the entirety of the transparent substrate 2a with the ultraviolet irradiation light source, and only one processing step is required.

On the other hand, in the etching method, even if the same mask and the same setting conditions (for example, temperature, gas atmosphere, time, etc.) are used, depending on how light hits at that time, the density distribution of temperature and gas atmosphere concentration, and the like. Variations increase. This is not suitable for an alignment division substrate for a liquid crystal element in which the height must be severely controlled on the order of 0.01 mm. Further, if a transparent electrode having a complicated shape is to be formed by controlling the moving speed using a mask as in the related art (see FIG. 6), very complicated mask control is required, and the processing time is increased. Very long.

Further, the base layer 22 can be formed only by embossing with the stamper 27 and then irradiating ultraviolet rays to cure the ultraviolet curable resin 26, so that the orientation is smaller than the method using a thermosetting resin or the etching method. The processing time per divided substrate can be reduced. The processing time for one orientation-divided substrate is inevitably time-consuming in principle as long as a conventional etching method is used, for example, and has been a major bottleneck when considering industrial mass production.

Further, in the conventional method, the thickness of the transparent electrode itself becomes non-uniform. Therefore, if the driving method of the liquid crystal display element is not devised, unevenness may occur in the pixel in some cases.
On the other hand, in the orientation division substrate 21 of the present invention, such a problem can be solved because the thickness of the transparent electrode 23 can be made uniform.

In the liquid crystal display element, when the resistance value of the transparent electrode increases, black and white stripes, which are called crosstalk or shadowing, occur on the screen. This crosstalk or shadowing is generally caused by "blurring of the drive waveform" and has been improved by the driving method in recent years. However, it is said that the most effective method is to reduce the resistance of the transparent electrode. In addition, the rounding of the drive waveform causes a difference in applied voltage between a pixel close to the drive driver IC and a pixel far from the drive driver IC, and the applied voltage is smaller in a pixel far from the drive driver IC than in a close pixel. That is, the brightness (brightness) of a pixel far from the drive driver IC is darker than that of a pixel close to the drive driver IC, and the display is dark and blurred.

However, in the method of changing the thickness by etching the transparent electrode, the thickness of the transparent electrode is reduced by etching at a portion corresponding to the concave portion, and the resistance value of the transparent electrode locally increases at this portion. In addition, the resistance value of the transparent electrode is increased in the entire liquid crystal display element, and the display quality of the liquid crystal display element is reduced. On the other hand, in the alignment division substrate 25 of the present invention, the thickness of the transparent electrode 23 is uniform, and it is not necessary to partially reduce the thickness of the transparent electrode.
An increase in the resistance value of the transparent electrode 23 can be suppressed.

Thus, according to the present invention, it greatly contributes to the demand for a wide viewing angle of the liquid crystal display element, and the smoothness of the surface of the transparent electrode sufficiently satisfies the demand for the liquid crystal display element.
Crosstalk and shadowing do not increase (display quality), and it becomes possible to easily and mass-produce the alignment division substrate. Further, according to the present invention, since there is little variation in manufacturing (variation within the same liquid crystal display element, variation between liquid crystal display elements), it is possible to stably obtain the above-described effects (for example, a wide viewing angle). It has excellent industrial productivity.

In the 2P method according to the present invention, the etching method is used for patterning the transparent electrode. However, this method is only used to obtain a plane pattern of the transparent electrode. There is no such problem. In particular, since the patterning of the transparent electrode can be collectively etched over the entire surface of the transparent substrate using a mask having a sufficiently large dimension, the number of steps is not greatly increased.

(Another manufacturing method) In the example of FIG.
Although it appears that the underlayer 22 and the underlayer 22 are separated from each other, a thin resin film is likely to remain in this portion due to the gap between the stamper 27 and the transparent substrate 2a. However, even when a thin resin film remains, its thickness can be suppressed to about 0.5 to 2 μm. Alternatively, FIG.
As shown in (g), a space is left between the stamper 27 and the transparent substrate 2a, and a thick resin film 22a (for example, a thickness of about several tens of μm) is left between the underlayer 22 and the underlayer 22. Is also good.

(Manufacturing Method of Stamper) A manufacturing method of the stamper 27 is shown in FIG. First, FIG.
As shown in (b), the glass plate 31 is directly laser-processed, and a desired concavo-convex pattern 32 is formed on the surface of the glass plate 31 (that is, the glass substrate 31 has the same shape as the surface shape of the transparent substrate 2a on which the underlayer 22 is formed) , Which are stored in advance in a computer that controls the laser processing apparatus). After forming a master by forming a desired concavo-convex pattern 32 on the surface of the glass plate 31, nickel is deposited on the master, and a nickel master 33, which is an inverse of the master, is formed by nickel electroforming.
[FIG. 13 (c)], and the nickel master 33 is peeled off from the master [FIG. 13 (d)]. When preparing the nickel master 33 by the nickel electroforming method, the master is made conductive by, for example, a vapor deposition method or an electroless plating method as a preparation, and the surface of the conductive master is used as a cathode, for example, in a nickel sulfamate bath. The nickel master 33 is manufactured by electroplating.

Since the nickel master 33 thus obtained also has the same concave shape 34 as the concave shape 28 of the stamper 27, the nickel master 33 can be used as the stamper 27, but usually (industrial) this nickel master 33 is used. Is further duplicated by a nickel electroforming method to obtain a stamper 27. In the case of replicating the nickel master 33, a mother 35 (master) having a convex mold 36 whose concave mold 34 is inverted by nickel electroforming after forming an oxide film on the surface of the nickel master 33 by, for example, a potassium dichromate solution. 13 (e)], and an inverted mold of the mother 35 is manufactured by nickel electroforming, and a stamper 27 which is a copy of the nickel master 33 is manufactured [FIG. 13 (f)]. Therefore, when the stamper 27 is worn, it can be copied from the mother 35 again.

In order to fabricate the stamper 27, FIG.
As shown in FIGS. 4 (a) to 4 (f), a master may be manufactured by laser processing the resist 37 applied to the surface of the glass plate 31. When the resist 37 is used, a silane coupling agent, for example, is applied to the surface of the glass plate 31 as an adhesive between the glass plate 31 and the resist 37, and after laser processing, the steps of exposure, development, and cleaning are performed. As a result, the concavo-convex pattern 32 of the resist 37 is formed on the surface of the glass plate 1. The subsequent processing is shown in FIG.
(C) Perform as follows.

In the liquid crystal display element 21 of the above embodiment, the case where the alignment division substrate 25 is used only on the back surface side has been described. However, the alignment division substrate 25 may be used only on the front surface side. The substrate 25 may be used.

In the above embodiment, the underlayer 22 is shown as having an isosceles triangular cross section (FIG. 9). However, the transparent electrode 23 and the alignment film 24 are formed in a single pixel.
In order to form a surface having at least two or more inclination angles, the underlayer 22 having various shapes other than this is possible. For example, as shown in FIG.
2. Underlayer 22 having a large number of inclined surfaces as shown in FIG.
May be.

(Second Embodiment) FIG. 17 is a sectional view showing another example of the alignment division substrate 41 used in the liquid crystal display device according to another embodiment of the present invention. This alignment division substrate 41
In FIG. 18, an underlayer 42 having a width of about 1/2 or less of the pixel pitch and having a flat surface (one underlayer 42 is shown in FIG. 18)
Are formed for each pixel pitch on the surface of the transparent substrate 2a. Therefore, when a transparent electrode material is deposited on the surface of the transparent substrate 2a from above the underlayer 42 to form the transparent electrode 23, the surface of the transparent electrode 23 is formed on the underlayer 42 and in a part deviating from the underlayer 42. Although the surface is flat, the surface of the transparent electrode 23 is relatively high on the underlayer 42, and the surface of the transparent electrode 23 is relatively low on a portion outside the underlayer 42.

Therefore, even when the alignment film 24 is formed on the alignment division substrate 41, the alignment film 2 is formed within one pixel.
Part of 4 is higher than other parts.

In general, the liquid crystal molecules are characterized in that the pretilt angle is reduced when the rubbing is pushed in, and the pretilt angle is increased when the rubbing is pushed in weakly. FIG. 19 shows the alignment film 24 as Nissan Chemical Industry Co., Ltd.
Liquid crystal (ZLI-22) obtained by rubbing with a rayon cloth and uniformly rubbing using “SE-3710” manufactured by
93) It shows the relationship between the pretilt angle (or tilt angle) of the molecule and the rubbing depression amount. From this, it can be seen that the pretilt angle becomes smaller as the pressing force increases. Therefore, as in the embodiment of FIG.
When the transparent electrode 23 has a step, even if the rubbing is performed uniformly, the push-in becomes relatively strong at a portion where the transparent electrode 23 is high and protrudes, and the pretilt angle is reduced. On the other hand, in the portion where the transparent electrode 23 is low,
Since the pushing is weak, the pretilt angle increases. Therefore, when a liquid crystal display element is manufactured using the alignment divided substrates 41 having different heights of the transparent electrodes 23 in two or more regions, the orientation of liquid crystal molecules is dispersed and the viewing angle of the liquid crystal display element is widened. be able to.

In a region other than the underlayer 42, a thin resin film 43 may remain as shown in FIG.

(Third Embodiment) In the orientation division substrate 44 shown in FIG. 20, an underlayer 42 having a step is formed in one pixel region. That is, the underlayer 42 is composed of the thick layer 42a and the thin layer 42a.
b and a transparent electrode 23 having a uniform thickness
Are formed. Even in such a structure, the amount of rubbing depression by the alignment film 24 can be changed. The underlayer 42 having three or more steps may be formed.

In the base layer 42 having such a shape, when the base layer 42 is transferred and formed on the transparent substrate 2a by the 2P method, the formed base layer 42 is hardly peeled off from the stamper 27, and the base layer 42 is formed on the transparent substrate 2a. There is a risk of peeling from 2a. Therefore, in order to improve the releasability of the underlayer 42 from the stamper 27, a release agent (a release agent) may be mixed in advance with the ultraviolet curable resin for forming the underlayer 42. Alternatively, as shown in FIG. 21, a chemical (generally called a primer) 45 having a function of improving the adhesion between the transparent substrate 2a and the base layer 42 is applied to the surface of the transparent substrate 2a in advance. Is also good. Alternatively, the above methods may be used in combination.

(Fourth Embodiment) FIG. 22 is a sectional view showing another example of the alignment division substrate 46 used in the liquid crystal display device according to still another embodiment of the present invention. In the orientation-divided substrate 46, a curved underlayer 47 (one underlayer 47 is shown in FIG. 23) is formed on the surface of the transparent substrate 2a at every pixel pitch. Therefore, this underlayer 47
When a transparent electrode material is deposited on the surface of the transparent substrate 2a from above to form the transparent electrode 23, the surface of the transparent electrode 23 is also curved. Therefore, also in this case, the pretilt angle of the liquid crystal molecules widely varies due to a change in the inclination of the surface of the transparent electrode 23 or a change in the rubbing amount, and the viewing angle of the liquid crystal display element is widened.

As the curved underlayer, a semi-cylindrical underlayer 47 as shown in FIG. 24 or a hemispherical underlayer 47 as shown in FIG. 25 may be provided.

(Fifth Embodiment) FIG. 26 is a partially broken sectional view showing a liquid crystal display element 48 according to still another embodiment of the present invention. In this liquid crystal display element 48,
A projection 49 is formed on the surface of the transparent substrate 2a between the underlayer 22 and the underlayer 22 (may be another type of underlayer). The projections 49 are formed by molding a UV-curable resin with a stamper to form the underlayer 22 by the 2P method.
It is formed of an ultraviolet curable resin at the same time as the underlayer 22. The height H of the projection 49 is formed such that 0.5d ≦ H ≦ 0.95d with respect to the size d of the space sealing the liquid crystal layer 3.

Usually, beads are dispersed in the liquid crystal layer in the liquid crystal display element in order to prevent the transparent substrates from contacting each other when pressed. However, since such beads are soft, they are deformed when strongly pressed, and are easily deformed by heat. On the other hand, the protrusion 49
Can be molded with a hard ultraviolet-curable resin such as an epoxy resin, so that the liquid crystal display element 48 is hardly deformed even when pressed strongly, and is resistant to heat. Therefore, the liquid crystal display element 48
Is strongly pressed, the effect of preventing contact between the transparent electrodes 23 and 5b is high. The projections 49 can be used in combination with beads.

In each of the above embodiments, the case where the surface of the transparent substrate is made uneven by forming an underlayer on the surface of the transparent substrate by the 2P method or the like has been described. Alternatively, the unevenness (underlayer) may be integrally formed by embossing, or the unevenness may be formed on the surface of a transparent substrate made of a glass plate by etching or the like. However, the former method has poor shape stability and is easily deformed, and it is difficult to perform fine processing. Further, in the latter method, the accuracy (shape, height, flatness, and the like) of the etching of the glass plate is further poor, and cannot be said to be a good method. Therefore, the 2P method of forming a base layer on the surface of a transparent substrate using an ultraviolet curable resin is the most excellent.

[Brief description of the drawings]

FIG. 1 is a partially broken sectional view showing a conventional liquid crystal display device.

FIG. 2 is a diagram illustrating the order in which liquid crystal molecules are arranged in the liquid crystal display element of the above.

FIG. 3 is a partially broken sectional view showing another conventional liquid crystal display element.

FIG. 4 is a diagram showing the relationship between the direction of liquid crystal molecules (pretilt angle) and the refractive index of a liquid crystal layer.

FIG. 5 is a diagram showing a distribution of pretilt angles of liquid crystal molecules in the above liquid crystal display element.

FIGS. 6 (a), (b) and (c) are diagrams for explaining a method of forming a transparent electrode in the liquid crystal display element of the above.

FIG. 7 is a partially broken cross-sectional view illustrating a liquid crystal display device according to an embodiment of the present invention.

FIG. 8 is a partially broken cross-sectional view showing an alignment division substrate used in the above liquid crystal display element.

FIG. 9 is a perspective view showing a base layer formed on the alignment division substrate.

FIG. 10 is a view showing a state in which an alignment film is formed on the alignment division substrate and a rubbing process is performed.

FIGS. 11A to 11G are schematic views illustrating a method for manufacturing an alignment division substrate according to the first embodiment.

FIGS. 12A to 12G are schematic views illustrating another method for manufacturing an orientation-divided substrate according to the first embodiment.

FIGS. 13A to 13F are schematic views illustrating a method of manufacturing a stamper for forming an underlayer.

FIGS. 14A to 14F are schematic views illustrating another method of manufacturing a stamper for forming an underlayer.

FIG. 15 is a perspective view showing base layers having different shapes.

FIG. 16 is a perspective view showing an underlayer having a further different shape.

FIG. 17 is a partially broken cross-sectional view showing an alignment division substrate used in a liquid crystal display device according to another embodiment of the present invention.

FIG. 18 is a perspective view showing a base layer formed on the alignment division substrate.

FIG. 19 is a diagram showing the relationship between the pretilt angle of liquid crystal molecules and the amount of rubbing depression.

FIG. 20 is a partially broken sectional view showing an alignment division substrate used in a liquid crystal display device according to still another embodiment of the present invention.

FIG. 21 is a view for explaining a method for preventing separation between a base layer and a transparent substrate in the above-mentioned alignment division substrate.

FIG. 22 is a partially broken cross-sectional view showing an alignment division substrate used in a liquid crystal display device according to still another embodiment of the present invention.

FIG. 23 is a perspective view showing a base layer formed on the alignment division substrate.

FIG. 24 is a perspective view showing base layers having different shapes.

FIG. 25 is a perspective view showing an underlayer having a further different shape.

FIG. 26 is a partially broken sectional view showing a liquid crystal display device according to still another embodiment of the present invention.

[Explanation of symbols]

 2a, 2b Transparent substrate 3 Liquid crystal layer 22, 42, 47 Underlayer 23 Transparent electrode 24 Alignment film 26 UV curable resin 27 Stamper

Claims (5)

[Claims] 1. In each pixel region on a surface of a transparent substrate, a base layer having an uneven surface is formed for each pixel region, and a transparent electrode is formed on the whole of each pixel region from above the base layer. Substrate for orientation division. 2. In each pixel region on the surface of the transparent substrate, an underlayer is formed on a part of each pixel region, and a transparent electrode is formed on the entire pixel region from above the underlayer. Substrate. 3. A photo-curable resin is supplied onto a transparent substrate, and the irregularities are transferred to the photo-curable resin by a stamper having irregularities, and then the photo-curable resin is cured by irradiation with light. A method for manufacturing a substrate for orientation division, comprising: removing a stamper from irregularities formed by a photocurable resin; and then forming a transparent electrode in each pixel region from the irregularities. 4. A liquid crystal display device in which liquid crystal is sealed between a pair of transparent substrates having a transparent electrode and an alignment film formed thereon, wherein at least one of the transparent substrates having the transparent electrode and the alignment film formed thereon is transparent. In each of the pixel regions on the substrate surface, a base layer having irregularities on the surface is formed for each of the pixel regions, and a transparent electrode is formed over the entire pixel region from above the base layer. element. 5. A liquid crystal display device in which liquid crystal is sealed between a pair of transparent substrates on which a transparent electrode and an alignment film are formed, wherein at least one of the transparent substrates on which the transparent electrode and the alignment film are formed is transparent. A liquid crystal display device comprising: a base layer formed in a part of each pixel region in each pixel region on a substrate surface; and a transparent electrode formed on the entire pixel region from above the base layer.