JP2005316027A - Liquid crystal display element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element capable of displaying different display contents according to viewing directions. <P>SOLUTION: The liquid crystal display element has a first transparent substrate, a first substrate comprising first and second electrodes formed on one surface of the first transparent substrate and connected to mutually independent electric circuits to be controlled, a second transparent substrate, a second substrate comprising a third electrode formed on one surface of the second transparent substrate and disposed to be nearly parallel to the first substrate so that the surface of the first substrate on which the first and the second electrodes are formed and the surface on which the third electrode is formed are opposed to each other and a liquid crystal layer interposed between the first and the second substrates and provided with a first part wherein a liquid crystal falls in a first direction when voltage is applied between the first electrode and the third electrode and a second part wherein the liquid crystal falls in a second direction different from the first direction when voltage is applied between the second electrode and the third electrode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display element that displays different contents depending on the viewing direction, and a manufacturing method thereof.

  FIG. 13 is a cross-sectional view showing a conventional example of a vertical alignment type liquid crystal display element (Liquid Crystal Display). The vertical alignment LCD 50 is composed of a pair of substrates (upper substrate 31 and lower substrate 32) and a liquid crystal layer 39 sandwiched therebetween, for example, nematic liquid crystal molecules 39a having negative dielectric anisotropy (Δε <0). And a nematic liquid crystal layer to be formed. The upper substrate 31 and the lower substrate 32 are each formed of a transparent conductive material such as ITO (Indium Tin Oxide) on the transparent substrates 33 and 34, which are flat glass substrates, for example, and a predetermined glass substrate. It includes transparent electrodes 35 and 36 having patterns, and vertical alignment films 37 and 38 formed on the transparent electrodes 35 and 36.

  The pair of substrates (upper substrate 31 and lower substrate 32) are arranged substantially in parallel so that the vertical alignment films 37 and 38 face each other, and a liquid crystal layer 39 is sandwiched between the vertical alignment films 37 and 38. A voltage applying unit 43 is connected between the transparent electrodes 35 and 36, and an arbitrary voltage can be applied to the liquid crystal layer 39 between the transparent electrodes 35 and 36 by the voltage applying unit 43. The vertical alignment films 37 and 38 are subjected to an alignment process such as provision of a pretilt angle. By the alignment treatment, the liquid crystal molecules 39a of the liquid crystal layer 39 in contact with the vertical alignment films 37 and 38 are aligned in a direction substantially perpendicular to the substrates (upper substrate 31 and lower substrate 32) and inclined by a pretilt angle. In addition, when a voltage is applied to the liquid crystal layer 39, the pretilt angle defines the direction in which the liquid crystal molecules 39a are tilted.

  On the outside of the pair of substrates (upper substrate 31 and lower substrate 32), a pair of polarizing plates 41 and 42 are disposed, for example, in a crossed Nicols state. As shown in the figure, when defining the X direction, the Y direction, and the Z direction orthogonal to each other, the polarizing plate 41 facing the upper substrate 31 transmits, for example, only light polarized in the X direction and facing the lower substrate 32. For example, 42 is arranged to transmit only light polarized in the Y direction. Further, the pair of substrates (upper substrate 31 and lower substrate 32) sandwiching the liquid crystal layer 39 has a normal line direction of each substrate (upper substrate 31 and lower substrate 32) parallel to the Z direction, and When viewed from the normal direction (Z direction) of the upper substrate 31 or the lower substrate 32, the liquid crystal molecules at the time of voltage application are arranged so as to fall in a direction that forms 45 ° with the X direction and the Y direction.

  In the vertical alignment LCD 50, a viewing angle compensation film 40 is inserted between the upper substrate 31 and the polarizing plate 41 in order to improve the viewing angle dependency. As the viewing angle compensation film 40, for example, a uniaxial optical film having an optical axis in the normal direction of the film and a negative birefringence is used. The viewing angle compensation film 40 can be disposed only on one substrate side as shown in the figure, or can be disposed outside both substrates. The retardation of the viewing angle compensation film 40 is about 1 to 3 times that of the liquid crystal layer 39. When the viewing angle compensation film 40 is disposed on both the substrate sides, the sum of the retardations of the two viewing angle compensation films 40 is about 1 to 3 times the retardation of the liquid crystal layer 39.

  The vertical alignment type LCD 50 having the structure shown in FIG. 13 has a drawback that the viewing angle characteristics from the direction in which the liquid crystal molecules 39a are tilted are extremely deteriorated.

A pair of transparent electrodes formed on the upper and lower substrates is formed in a shape having slits, and the twisted nematic (Twisted), wherein the slits of one transparent electrode and the slits of the other transparent electrode are alternately arranged in the display region (Nematic, TN) liquid crystal display elements have been proposed. (For example, see Patent Document 1.)
According to this proposal, an oblique electric field is generated in the slit portion, and the direction in which the oblique electric field is inclined is reversed on both sides of the slit. In the display area of a pair of electrodes, when a voltage is applied, small areas with the opposite directions of the rising direction of the liquid crystal molecules are formed simultaneously, so that the viewing angle dependence of each small area is complemented, and the viewing area dependence of the entire display area Is reduced, visibility is improved from any direction, and display quality is improved.

  The above-mentioned liquid crystal display element can display the same content from any direction.

Japanese Patent No. 3108768

  An object of the present invention is to provide a liquid crystal display element capable of displaying different display contents depending on the viewing direction, and a method for manufacturing the same.

  According to one aspect of the present invention, a first transparent substrate and first and second electrodes formed on one surface of the first transparent substrate, which are connected to an independent electric circuit. A first substrate including first and second electrodes controlled, a second transparent substrate, and a third electrode formed on one surface of the second transparent substrate. The second substrate, wherein the first substrate has a surface on which the first and second electrodes are formed, and the surface on which the third electrode is formed faces each other. A second substrate disposed substantially in parallel with the first substrate, and a liquid crystal layer sandwiched between the first substrate and the second substrate, and between the first electrode and the third electrode When a voltage is applied to the first portion, the voltage is applied between the first portion where the liquid crystal falls in the first direction and between the second electrode and the third electrode. Come, the liquid crystal display device having a liquid crystal layer comprising a second portion falling down in a second direction different from the liquid crystal is the first direction is provided.

  This liquid crystal display element can display different display contents depending on the viewing direction.

  According to another aspect of the present invention, (a) films of alignment materials that are sensitive to light and have the property of aligning liquid crystal molecules in a direction substantially perpendicular to the surface on average are mutually independent. Forming a first substrate surface having first and second electrodes connected to and controlled by an electrical circuit; and (b) sensitive to light and liquid crystal molecules on average approximately perpendicular to the surface. A step of forming an alignment material film having a property of being oriented in a direction on the surface of the second substrate having electrodes; and (c) an alignment material film formed on the surfaces of the first and second substrates, respectively. Light is irradiated from a direction inclined from the normal direction of the first and second substrates, and two kinds of microregions having different pretilt angles from the vertical alignment are respectively formed at the positions where the first and second electrodes are formed. Forming at a corresponding position; (d) the first substrate; A method of manufacturing a liquid crystal display device, comprising: a step of arranging a liquid crystal layer between the first substrate and the second substrate so as to face each other with a surface on which an alignment material film is formed facing each other. Is provided.

  By using this liquid crystal display element manufacturing method, a liquid crystal display element capable of displaying different display contents depending on the viewing direction can be manufactured.

  Furthermore, according to another aspect of the present invention, (a) a film of an alignment material sensitive to light and having the property of aligning liquid crystal molecules in a direction substantially perpendicular to the surface on average is provided with a first electrode having electrodes. And (b) irradiating the alignment material film formed on the first substrate surface with light from a direction inclined from the normal direction of the first substrate, and from the vertical alignment. A step of forming two kinds of microregions having different pretilt angles, and (c) a film of an alignment material having a property of aligning liquid crystal molecules in a direction substantially perpendicular to the surface on the average. A step of forming on the substrate surface; and (d) the first substrate and the second substrate are disposed so as to face each other with the surface on which the film of the alignment material is formed facing each other. Forming a liquid crystal layer therebetween, and the electrode on the first substrate surface and the first substrate Any one of the electrodes on the substrate surface includes first and second electrodes that are connected to and controlled by mutually independent electric circuits, and in the step (b), the pretilt angles are different. There is provided a method for manufacturing a liquid crystal display element, in which two types of minute regions are formed at positions corresponding to the positions at which the first and second electrodes are formed.

  According to this method for manufacturing a liquid crystal display element, a liquid crystal display element capable of displaying different display contents depending on the viewing direction can be manufactured by a simplified manufacturing process. In addition, deterioration of display quality can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display element which can display the display content which changes with viewing directions, and its manufacturing method can be provided.

  In the background art, an invention of a liquid crystal display element that adopts a multi-domain structure to improve the defect of viewing angle dependency and realizes good visibility from any direction has been described. The present application proposes a liquid crystal display element and a method for manufacturing the liquid crystal display element that enable a plurality of different displays depending on the viewing direction by actively utilizing the defect of viewing angle dependency. This proposal is intended to realize a display having different display contents depending on the viewing direction with a single liquid crystal display element.

  In the embodiments described later, a plurality of regions having different viewing angle characteristics in the display region, that is, a so-called multi-domain structure is produced, and a different drive signal is applied to each of the plurality of regions. A liquid crystal display element that displays the above is taken up.

  Prior to that, the reason why different display contents are possible depending on the viewing direction will be described. Here, a liquid crystal display element having a two-domain structure is taken as an example to explain the reason why different displays can be realized when viewed from the left and right oblique directions.

  FIG. 1 is a view angle characteristic diagram of a vertical alignment type liquid crystal display device having a two-domain structure (a two-domain structure including a domain having a viewing angle in the right direction and a domain having a viewing angle in the left direction). The graph shown by the solid line shows the viewing angle characteristics of the domain with the viewing angle in the left direction (the domain where the liquid crystal molecules in the center of the liquid crystal layer tilt to the right), and the graph shown by the dotted line shows the domain with the viewing angle in the right direction ( It is a graph showing the viewing angle characteristic of the domain where the liquid crystal molecules in the center of the liquid crystal layer are tilted leftward. A graph in which white circles are connected by a solid line or a dotted line indicates a case where an ON voltage is applied, and a graph in which white squares are connected by a solid line or a dotted line indicates a case where an OFF voltage is applied. The horizontal axis indicates the viewing angle to the left and right sides in the unit “° (degree)”. The normal direction of the substrate is 0 °, and the viewing angle to the right is positive. The vertical axis indicates the transmittance of light incident on the liquid crystal display element in the unit “%”.

  Due to the fact that the liquid crystal display element has a two-domain structure having substantially the same viewing angle in both the left and right directions, a graph in which white circles are connected by a solid line, a graph in which white circles are connected by a dotted line, and a graph in which white squares are connected by a solid line A graph in which white squares are connected by a dotted line is symmetric with respect to a line having a viewing angle of 0 °.

  Refer to the two graphs that connect the white squares with solid or dotted lines. It can be seen that in both the domain having the viewing angle in the right direction and the domain having the viewing angle in the left direction, when the OFF voltage is applied, the transmittance of incident light is almost 0% regardless of the viewing angle direction, and effective display cannot be performed. .

  Refer to two graphs with white circles connected by solid or dotted lines. For example, when the display region is viewed from the substrate normal direction (viewing angle 0 ° direction) when the ON voltage is applied, the light transmittance of the two types of domains is equal, and therefore the display of both types of domains is evenly mixed. I understand.

  On the other hand, in a domain having a viewing angle in the left direction (a graph in which white circles are connected by a solid line), the light transmittance in the range from 20 ° to 55 ° on the right side is almost the same as that when an OFF voltage is applied (about 0). %). Further, in a domain having a viewing angle in the right direction (a graph in which white circles are connected by a dotted line), the light transmittance is approximately the same as that when an OFF voltage is applied (about 0) in the range of viewing angles from 20 ° to 55 ° on the left side. %). For this reason, when viewing the display region from the viewing angle range of 20 ° to 55 ° on the right side, only the display of the domain having the viewing angle in the right direction is allowed, and the display of the domain having the viewing angle in the left direction is not allowed. On the contrary, when viewing the display area from the viewing angle range of 20 ° to 55 ° on the left side, only the display of the domain with the viewing angle in the left direction is permitted, and the display of the domain with the viewing angle in the right direction is permitted. I can't.

  Accordingly, separate display electrodes are provided for the two types of domains, different driving voltages are applied to the respective electrodes, and different displays are performed in the two types of domains, and a certain range (for example, from a viewing angle of 20 ° to 55 °). It is possible for a person observing the display area to recognize different displays. Note that the viewing angle range in which different displays can be recognized can also be adjusted by the applied voltage.

  The reason why different contents can be displayed depending on the viewing direction in the two-domain liquid crystal display element has been described above. For the same reason, even in a multi-domain liquid crystal display element having three or more types of domains, it is possible to perform different displays for different domains and to allow different viewers to recognize different displays. is there. However, in twisted nematic liquid crystal display elements, vertical alignment type liquid crystal display elements, etc., when an ON voltage is applied, a certain one position (in the twisted nematic liquid crystal display element, the direction in which the liquid crystal molecules rise and the opposite side in the plane including the liquid crystal molecules) The vertical alignment type liquid crystal display element has a feature that the light transmittance is lowered only in the direction in which the liquid crystal molecules are tilted. Therefore, a liquid crystal display element that displays different contents to viewers with different viewing directions may be optimally realized with a two-domain structure.

  FIG. 2 is a schematic cross-sectional view showing an example of a vertical alignment type liquid crystal display element according to the first embodiment. It differs from the conventional liquid crystal display element shown in FIG. 13 in the following points.

  First, in the liquid crystal display device according to the first embodiment, the transparent electrode 35 (segment electrode) is composed of two different comb-like electrodes 35a and 35b.

  Both the comb-shaped electrodes 35a and 35b have a plurality of comb-shaped portions with a certain width and formed at a certain pitch. Further, regarding the two comb-like electrodes 35a and 35b, the width and the formation pitch of the comb-like portions are both equal. The two comb-like electrodes 35a and 35b are arranged such that the comb-like portions are alternately spaced (interdigital) along the width direction of the comb-like portion of the electrode (the left-right direction in FIG. 2). ing.

  A voltage applying means 43a is connected between one comb-like electrode 35a and the transparent electrode 36 (common electrode) to form one electric circuit. It is possible to apply a voltage of Between the other comb-like electrode 35b and the transparent electrode 36 (common electrode), a voltage applying means 43b is connected to form the other electric circuit, whereby an arbitrary voltage is applied between the two electrodes. can do. Thus, two electric circuits independent from each other are formed by the two comb-like electrodes 35a and 35b, and different voltages (drive signals) are applied and controlled by the voltage applying means 43a and 43b in each circuit. be able to. The arrangement of the segment electrodes (comb-like electrodes 35a and 35b) and the common electrode (transparent electrode 36) will be described in detail later.

  In the liquid crystal display element, two regions (domains 80a and 80b) in which the alignment directions of the liquid crystal molecules 39a are different from each other (for example, opposite directions) are formed corresponding to the formation positions of the comb-like electrodes 35a and 35b. ing. In FIG. 2, along the normal direction of the substrates (upper substrate 31 and lower substrate 32), a region (domain 80a) in which the liquid crystal molecules 39a are tilted to the left is aligned with the formation position of the comb-like electrode 35a. Yes. In addition, a region (domain 80b) in which the liquid crystal molecules 39a are tilted to the right is aligned with the formation position of the comb-like electrode 35b. The domains 80a and 80b are formed in a region including at least a part of the comb-like portions of the comb-like electrodes 35a and 35b when viewed from the normal direction of the substrate in a stripe shape that is long in the direction perpendicular to the paper surface of FIG. Is done. The domain 80a has a viewing angle in the right direction of the figure, and the domain 80b has a viewing angle in the left direction of the figure. The two types of domains 80a and 80b are alternately formed in the left-right direction in FIG.

  When attention is paid to one domain, the directions of the pretilt angles given to the upper substrate 31 and the lower substrate 32 are opposite to each other. When attention is paid to one substrate (the upper substrate 31 or the lower substrate 32), the pretilt angles given to the adjacent regions (domains in FIG. 2 in the left-right direction) are opposite.

  By applying a drive signal (voltage) using the comb-like electrode 35a to one domain 80a and applying another drive signal (voltage) using the comb-like electrode 35b to the other domain 80b. Different contents can be displayed for each of two types of domains having different viewing angles. That is, one domain 80a is controlled using the comb-like electrode 35a and the voltage applying means 43a, and the other domain 80b is controlled using the comb-like electrode 35b and the voltage applying means 43b.

  FIG. 3 is a schematic plan view showing part of the segment electrodes (comb-like transparent electrodes 35a and 35b) and the common electrode (transparent electrode 36). The two comb-like electrodes 35a and 35b are formed and arranged so that the comb-like portions are alternately (interdigital) along the width direction of the comb-like portions of the electrodes. , 35b, two types of domains 80a and 80b having different viewing angle directions are controlled to perform different display for each of the domains 80a and 80b.

  In the figure, each comb-like electrode 35a, 35b is simplified to show three comb-like portions, but the comb-like electrodes 35a, 35b actually have more comb-like portions. . The width of the comb-like portion of each comb-like electrode 35a, 35b is, for example, 40 μm, and the interval between adjacent comb-like portions is 60 μm. Accordingly, the comb-like portions of the comb-like electrodes 35a and 35b are formed at a pitch of 100 μm. In the state where the comb-like portions of the two comb-like electrodes 35a and 35b are alternately arranged, the interval between adjacent comb-like portions is, for example, 10 μm. Therefore, the comb-like portions are arranged at a pitch of 50 μm.

  4A to 4C are schematic views illustrating an example of a display area of the liquid crystal display element according to the first embodiment. Shown is a display area of a liquid crystal display element that displays the state of the in-vehicle air conditioner in a segment display.

  Reference is made to FIG. The temperature is displayed on the two 7-segment display units in the upper left. In the lower right figure (bar graph), the air-conditioning air volume is displayed. This liquid crystal display element is installed near the center console of a car, for example.

  Reference is made to FIG. FIG. 4B shows a display displayed in a domain having a viewing angle on the left side (display recognized by an observer viewing the display area from the left side). In the passenger seat of the car, it is shown that the air conditioner is adjusted to a temperature of 19 ° C. and an air volume of level 2.

  Reference is made to FIG. FIG. 4C shows a display displayed in a domain having a viewing angle on the right side (display recognized by an observer viewing the display area from the right side). In the driver's seat of the car, it is shown that the air conditioner is adjusted to a temperature of 23 ° C. and an air volume of level 4.

  This liquid crystal display element capable of changing the alignment state of the liquid crystal by applying different voltages for each of the two types of domains having the viewing angle directions on the left and right sides, for example, includes a driver seat and a passenger seat. It will be suitably used as a display element when air-conditioning is performed separately.

  FIGS. 5A to 5E are schematic views for explaining a manufacturing method (first manufacturing method) of the liquid crystal display element according to the first embodiment having the structure shown in FIG.

  Reference is made to FIG. For example, on a transparent substrate 33 which is a flat glass substrate, a transparent conductive material film such as ITO is produced by sputtering and patterned into a predetermined shape to form a transparent electrode 35 (two comb-like electrodes 35a and 35b). . Next, a film of an alignment material that is sensitive to light, for example, ultraviolet light, and has the property of aligning liquid crystal molecules in a predetermined direction with respect to the surface on the average is formed on the transparent substrate 33 with a transparent electrode 35 (comb-like electrode 35a). , 35b). For example, a side chain type ultraviolet sensitive vertical alignment film 37 is applied to a thickness of 500 mm and cured. The vertical alignment film 37 aligns liquid crystal molecules on average approximately perpendicular to the surface. For the vertical alignment film 37, for example, SE-1211 manufactured by Nissan Chemical Industries is preferably used.

  FIG. 5B is a schematic plan view of a mask 55 which is a light shielding means used when the vertical alignment film 37 is exposed to light, for example, ultraviolet rays, and subjected to alignment treatment. The mask 55 has a configuration in which openings 55a and light shielding portions 55b that are formed in parallel stripes (stripes) with the same width appear alternately. The widths of the openings 55a and the light-shielding portions 55b are formed to be the same as the formation pitch of the comb-like portions of the comb-like electrodes 35a and 35b arranged alternately (interdigital).

  Reference is made to FIG. The mask 55 is disposed on the alignment film 37, and light such as ultraviolet rays is irradiated from an oblique direction (a direction inclined from the normal direction of the transparent substrate 33). The arrangement of the mask 55 is transparent so that the length direction of the comb-like portions of the comb-like electrodes 35a and 35b and the length direction of the opening 55a (or the light shielding portion 55b) of the mask 55 are parallel to each other. When viewed from the normal direction of the substrate 33, one of the comb-like portions of the two comb-like electrodes 35a and 35b is completely hidden by the light-shielding portion 55b, and the other is completely exposed from the opening 55a. To place. The ultraviolet irradiation direction is, for example, a direction inclined by 45 ° from the normal direction of the vertical alignment film 37 (the normal direction of the transparent substrate 33). Ultraviolet rays are applied to the vertical alignment film 37 through a bandpass filter centered at a wavelength of 254 nm, for example. For example, the illuminance per unit area at a wavelength of 254 nm is 1.35 mW, and the irradiation time is 3 minutes.

  Reference is made to FIG. Next, the mask 55 is moved from the state shown in FIG. 5C by a half pitch (in the width direction) in the direction orthogonal to the length direction of the opening 55a (or the light shielding portion 55b) (of the opening 55a or the light shielding portion 55b). Alignment is made by shifting by (width) and is arranged on the vertical alignment film 37, and light, for example, ultraviolet rays is irradiated from an oblique direction (direction inclined from the normal direction of the transparent substrate 33) different from the first irradiation. In the state shown in FIG. 5C, the opening 55a is newly brought into contact with the region on the vertical alignment film 37 with which the light shielding portion 55b is in contact, and the region with which the opening 55a is in contact is newly added. The light-shielding portion 55b is brought into contact with. For this reason, the ultraviolet rays are irradiated to the region where the ultraviolet rays were not irradiated in the process described with reference to FIG. In the second ultraviolet irradiation, the normal direction of the vertical alignment film 37 (of the transparent substrate 33) is within the plane including the first ultraviolet irradiation direction and the normal direction of the vertical alignment film 37 (the normal direction of the transparent substrate 33). With respect to the (normal direction), the irradiation is performed from a direction opposite to the first irradiation, for example, a symmetric direction. The illuminance per unit area and irradiation time of the ultraviolet rays to be irradiated are equal to those of the first ultraviolet irradiation shown in FIG. By such a photo-alignment process, a substrate 31 having two kinds of pretilt angles is obtained.

  Subsequently, the other substrate 32 of the vertical alignment type liquid crystal display element to which two kinds of pretilt angles are given is manufactured by a process similar to the process described with reference to FIGS. Since the transparent electrode 36 (common electrode) of the substrate 32 is not comb-shaped, in the description given with reference to FIG. 5C, the comb-shaped portion, the opening 55a of the mask 55, and the light-shielding portion 55b. Although alignment is not performed, alignment of the mask is performed so that a predetermined pretilt angle is given to a region corresponding to a predetermined position of the transparent electrode 36 (common electrode). At this time, since the two substrates 31 and 32 are bonded with the pretilt angle aligned in a subsequent process (described in the next paragraph), the mask is accurately aligned.

  Reference is made to FIG. The pair of substrates 31 and 32 are arranged so that the pretilt angle corresponds between the substrates 31 and 32 (when liquid crystal is injected between the substrates 31 and 32 in a later step, the alignment direction of the liquid crystal molecules is aligned between the substrates 31 and 32. Position them so that they are aligned with each other, and then place them facing each other and bond them together. Adhesion is performed, for example, by superimposing both substrates 31 and 32 coated with an ultraviolet curable main sealant via a gap control agent and irradiating ultraviolet rays to cure the main sealant. As the gap control agent, for example, catalyst chemical industrial silica beads having a diameter of 4.0 μm are preferably used. After bonding, both substrates 31 and 32 are cut in cell units, a liquid crystal (for example, Δn = 0.15 manufactured by Merck) is injected between the substrates 31 and 32 by a vacuum injection method, the injection port is sealed, and a liquid crystal layer 39 is formed to obtain a liquid crystal display element.

Polarizing plates 41 and 42 and a viewing angle compensation film 40 are disposed outside the liquid crystal display element. In this way, a two-domain vertical alignment type liquid crystal display element having two kinds of strip-like microregions in which liquid crystal molecules are tilted in opposite directions when a voltage is applied, and a liquid crystal display capable of different display for each domain An element can be manufactured.
6A to 6E are schematic cross-sectional views for explaining a second manufacturing method of the liquid crystal display element according to the first embodiment.

  Reference is made to FIG. Comb-like electrodes 35a and 35b (segment electrodes) to which a predetermined pattern is applied are formed on the transparent substrate 33 by a process similar to the process described with reference to FIG. , 35b, a vertical alignment film 37 is formed. The material, thickness, and formation method are also the same as those described with reference to FIG.

  Reference is made to FIG. A part of the vertical alignment film 37 is irradiated with the first light, for example, ultraviolet rays. Using the mask 55 shown in FIG. 5B, a pretilt angle is given by a photo-alignment process in a process similar to the process described with reference to FIG. The wavelength of the ultraviolet rays to be irradiated, the illuminance per unit area, the irradiation time, and the irradiation direction are the same as described with reference to FIG. Mask alignment is performed so that a predetermined pretilt angle is given to a region corresponding to a predetermined position of the comb-shaped electrodes 35a and 35b (segment electrodes).

  Reference is made to FIG. A part of the vertical alignment film 37 is irradiated with the second light, for example, ultraviolet rays. In a process similar to that described with reference to FIG. 5D, ultraviolet light is irradiated from a direction different from that of the first ultraviolet irradiation to a part of the region where the ultraviolet irradiation is not performed by the first ultraviolet irradiation. To give a pretilt angle. The wavelength of ultraviolet rays to be irradiated, the illuminance per unit area, the irradiation time, and the irradiation direction are the same as those described with reference to FIG. In this way, one substrate 31 of the liquid crystal display element is obtained. In addition, what is necessary is just to select conditions, such as a wavelength of ultraviolet-rays to irradiate, an intensity | strength, and an irradiation angle, in the process shown to FIG. 6 (B) and (C), in order to provide a desired pretilt angle.

  Reference is made to FIG. In addition to the steps described with reference to FIGS. 6A to 6C, a transparent pattern in which a predetermined pattern is given on the transparent substrate 34 by the same steps as those described with reference to FIG. An electrode 36 (common electrode) is formed, and a vertical alignment film 38 is formed on the transparent substrate 34 so as to cover the transparent electrode 36 (common electrode). The material, thickness, and formation method are also the same as those described with reference to FIG. However, the vertical alignment film 38 need not be formed of a photosensitive material. In this way, the other substrate 32 of the liquid crystal display element is obtained.

  Reference is made to FIG. The pair of substrates 31 and 32 are bonded so that the surfaces on which the vertical alignment films 37 and 38 are formed are aligned so that predetermined electrode patterns of the two transparent electrodes 35 and 36 overlap each other. , 32 to supply liquid crystal to obtain a liquid crystal layer 39. The bonding method between the substrates 31 and 32, the gap control agent to be used, the liquid crystal material injected between the substrates 31 and 32, and the method for forming the liquid crystal layer are those used in the description made with reference to FIG. It is the same. Thus, a liquid crystal display element according to the second manufacturing method can be manufactured.

  In the liquid crystal display element according to the second manufacturing method, a predetermined pretilt angle is given to the surface in contact with the liquid crystal layer 39 of one substrate 31 by photo-alignment processing, and a vertical alignment film 38 is formed on the other substrate 32. It is a liquid crystal display element that has been subjected to a simple vertical alignment process that has only been coated and cured. This is different from the liquid crystal display element according to the first manufacturing method shown in FIG.

  Also in the liquid crystal display element according to the second manufacturing method, the strip-shaped minute regions that are distinguished into two types by the pretilt angle from the vertical alignment applied by the photo-alignment process on the substrate 31 are unidirectional (the strip-shaped It appears alternately in the width direction of the minute region, in the left-right direction in FIG. These two types of strip-shaped minute regions are formed corresponding to the positions where the comb-shaped portions of the comb-shaped electrodes 35a and 35b are formed. When a voltage is applied, the liquid crystal molecules are tilted in the opposite direction according to the pretilt angle for each of the two types of minute regions. The liquid crystal molecules in contact with the vertical alignment film 38 have a substantially vertical alignment with respect to the vertical alignment film 38. Different driving signals (voltages) can be applied to the two kinds of minute regions by the comb-like electrodes 35a and 35b to display different contents in the viewing angle direction.

  According to the second manufacturing method, only one substrate 31 is subjected to photo-alignment processing to form two kinds of micro regions (2 domains) having different pretilt angles from the vertical alignment, so the manufacturing process is simplified. Thus, a liquid crystal display element that displays different contents depending on the viewing direction can be manufactured at low cost. Further, in the overlapping process (adhesion process) of both the substrates 31 and 32 described with reference to FIG. 6E, the work load is reduced because there is no need for highly accurate alignment. Furthermore, since the problem of insufficient alignment accuracy does not occur, deterioration in display quality can be reduced, and a high-quality liquid crystal display element can be manufactured.

  7A to 7E are schematic cross-sectional views for explaining a third manufacturing method of the liquid crystal display element according to the first embodiment.

  Reference is made to FIG. Comb electrodes 35a and 35b (segment electrodes) to which a predetermined pattern is applied are formed on the transparent substrate 33 by the same process as described with reference to FIG. A vertical alignment film 37 is formed on 35b (segment electrode). The material, thickness, and formation method are also the same as those described with reference to FIG.

  Reference is made to FIG. First vertical light, for example, ultraviolet irradiation is performed on the vertical alignment film 37. In the first and second manufacturing methods, the mask 55 is used at the time of the first ultraviolet irradiation, but in the third manufacturing method, for example, the entire surface of the vertical alignment film 37 is irradiated with ultraviolet rays without using the mask 55. Irradiation is performed to give a pretilt angle by photo-alignment treatment. The wavelength of the ultraviolet rays to be irradiated, the illuminance per unit area, the irradiation time, and the irradiation direction are the same as described with reference to FIG.

  Reference is made to FIG. A part of the vertical alignment film 37 irradiated with ultraviolet rays is irradiated with the second light, for example, ultraviolet rays. Unlike the first time, the second ultraviolet irradiation is performed by providing a mask 55 on the vertical alignment film 37 and irradiating ultraviolet rays from a direction different from the first ultraviolet irradiation to give a pretilt angle. . The wavelength of ultraviolet rays to be irradiated, the illuminance per unit area, and the irradiation direction are the same as those described with reference to FIG. However, the ultraviolet irradiation time is 6 minutes, which is twice as long as the first ultraviolet irradiation. By appropriately setting the second ultraviolet irradiation time performed using the mask longer than the first ultraviolet irradiation time performed without using the mask, for example, 1.2 times to 3.0 times appropriately. A pretilt angle can be provided. In this way, one substrate 31 of the liquid crystal display element is obtained. In addition, what is necessary is just to select conditions, such as a wavelength of ultraviolet-rays to irradiate, an intensity | strength, and an irradiation angle, in the process shown to FIG. 7 (B) and (C), in order to provide a desired pretilt angle.

  Reference is made to FIG. In addition to the steps described with reference to FIGS. 7A to 7C, a transparent pattern in which a predetermined pattern is provided on the transparent substrate 34 by a step similar to the step described with reference to FIG. An electrode 36 (common electrode) is formed, and a vertical alignment film 38 is formed on the transparent substrate 34 so as to cover the transparent electrode 36 (common electrode). The material, thickness, and formation method are also the same as those described with reference to FIG. However, the vertical alignment film 38 need not be formed of a photosensitive material. In this way, the other substrate 32 of the liquid crystal display element is obtained.

  Reference is made to FIG. A liquid crystal layer 39 is obtained by a process similar to the process described with reference to FIG. The bonding method of both the substrates 31 and 32, the gap control agent to be used, the liquid crystal material injected between both the substrates 31 and 32, and the liquid crystal layer forming method are also used in the description made with reference to FIG. It is the same.

  The liquid crystal display element manufactured by the third manufacturing method also has the same structure, function, and effect as the liquid crystal display element manufactured by the second manufacturing method.

  According to the third manufacturing method, as in the second manufacturing method, only one substrate 31 is subjected to photo-alignment processing to form two kinds of microregions (two domains) having different pretilt angles from the vertical alignment. Therefore, the manufacturing process can be simplified, and a liquid crystal display element that displays different contents depending on the viewing direction can be manufactured at low cost. In addition, in the step of overlaying (bonding step) between the substrates 31 and 32 described with reference to FIG. 7E, high-precision alignment is not necessary, and in the step shown in FIG. 7C. Since the mask alignment at the time of the second ultraviolet irradiation, which is necessary in the second manufacturing method, is unnecessary, the work load is reduced. Since the problem of insufficient alignment accuracy does not occur, deterioration in display quality can be reduced, and a high-quality liquid crystal display element can be manufactured.

  In the second manufacturing method and the third manufacturing method, only the vertical alignment film on the segment electrode side was subjected to photo-alignment treatment. When a two-domain alignment film is set on the segment electrode side, the two-domain region is divided along the comb-shaped electrodes of the segment, so that it becomes easy to set the reference point during manufacturing. In addition, the positioning accuracy when the substrates are stacked can be performed with the same positioning accuracy as the stacking accuracy of the liquid crystal display elements that do not have a multi-domain structure. Note that the alignment treatment can be performed only on the vertical alignment film on the common electrode side.

  When the display of the liquid crystal display element according to the first embodiment manufactured by the first to third manufacturing methods was observed, different display contents in the left-right direction could be confirmed.

  Hereinafter, as described with reference to the drawings, the liquid crystal display element according to the second embodiment is provided with a slit at a predetermined position of the common electrode (transparent electrode 36) as compared with that according to the first embodiment. The point is different. In the liquid crystal display element according to the first embodiment, two types of regions having different pretilt angles in different directions are alternately formed on at least one substrate (alignment film), and the vertical generated in the liquid crystal layer 39. A two-domain structure was realized using an electric field. In the second embodiment, a two-domain structure is realized by using a two-direction oblique electric field generated between a segment electrode composed of two comb-shaped electrodes and a common electrode having a slit.

  For this reason, in the liquid crystal display element according to the second embodiment, the alignment film is not subjected to special alignment treatment such as provision of a pretilt angle. The liquid crystal display element according to the second embodiment is, for example, a liquid crystal display element that has been subjected to a simple alignment process in which a vertical alignment film is applied and cured so as to cover a transparent electrode (segment electrode, common electrode) on a transparent substrate. It is. Moreover, an alignment film is not necessarily required.

  FIG. 8A is a schematic plan view showing part of the segment electrodes (transparent comb-like electrodes 35a and 35b) and the common electrode (transparent electrode 36) of the liquid crystal display device according to the second embodiment. FIG. 8B is a cross-sectional view taken along line 8B-8B in FIG. FIG. 8A is a diagram corresponding to FIG. 3 in the first embodiment, and is different from FIG. 3 in that a slit 36a is formed in the transparent electrode 36 (common electrode). 8B also shows the transparent substrates 33 and 34 on which the transparent electrodes 35 and 36 (segment electrodes and common electrodes) are formed.

  Reference is made to FIG. In the transparent electrode 36 (common electrode), when viewed from the normal direction of the substrate (the direction perpendicular to the paper surface in FIG. 8A), the comb-like portions of the two comb-like electrodes 35a and 35b are equally spaced. The slits 36a are formed at a constant pitch in the width direction of the comb-like portion (the left-right direction in FIG. 8A) in the portions arranged alternately (interdigital). The slit 36a has, for example, a stripe shape that is long in the length direction of the comb-shaped portion (vertical direction in FIG. 8A), and the slit width (length in the comb-shaped portion width direction) is constant. The slit 36a has a constant side edge in the length direction of the comb-like portion of one comb-like electrode 35a (left edge when FIG. 8 (A) is viewed from the upper side perpendicular to the paper surface) and the other comb facing it. It is formed so as to straddle a certain side edge in the length direction of the comb-like portion of the tooth-like electrode 35b (the right edge when FIG. 8A is viewed from the upper side perpendicular to the paper surface). In addition, the slit 36a is formed so that the edge in the length direction of the slit 36a is located in the inner region of the comb-shaped portions of the adjacent comb-shaped electrodes 35a and 35b.

  With reference to FIG. 8B, the operation and effect of the liquid crystal display element according to the second embodiment will be described. As described above, since the slit 36a is formed, the transparent electrode 36 (common electrode) portion between the adjacent slits 36a has a pair of adjacent comb teeth of the comb-shaped electrodes 35a and 35b in the illustrated cross section. It fits in the range of the width direction of the shape part. Due to such electrode arrangement, an oblique electric field 4 (an electric field in which the direction of the electric field is tilted from the normal direction of the substrate) is generated in the liquid crystal layer 39 when a voltage is applied.

  The direction of the oblique electric field 4 generated between the edge of each slit 36a formed in the transparent electrode 36 (common electrode) and the edge of the comb-like electrodes 35a, 35b (segment electrodes) is the same direction on a certain side of the slit 36a. (Directions parallel to each other). For example, the direction of the oblique electric field 4 generated between the right end portion of the slit 36a and the left end portion of the comb-like electrode 35a is the same direction (substantially parallel direction). The directions of the oblique electric field 4 generated between the left end of the slit 36a and the right end of the comb electrode 35b are also the same direction (substantially parallel direction). The directions of the two oblique electric fields 4 are different from each other (in opposite directions with respect to the normal lines of the transparent substrates 33 and 34).

  As a result, in the transparent electrode 36 (common electrode), two small regions α and β having different electric field directions are defined in a portion sandwiched between adjacent slits 36a. In addition, two small regions γ and δ having different electric field directions are also defined in a portion of the transparent electrode 36 adjacent to the small regions α and β across one slit 36a. The direction of the electric field in the small region α and the small region γ is the same direction, and the direction of the electric field in the small region β and the small region δ is the same direction. Further, the small region α and the small region γ generate an electric field in the liquid crystal layer 39 by the voltage applied between the comb-shaped electrode 35a, and the small region β and the small region δ are connected to the comb-shaped electrode 35b. An electric field is generated in the liquid crystal layer 39 by a voltage applied therebetween.

  Thus, the voltage applied between the one comb-shaped electrode 35a is applied between the region where the oblique electric field 4 is generated in one direction in the liquid crystal layer 39 and the other comb-shaped electrode 35b. A region where the oblique electric field 4 in the other direction is generated in the liquid crystal layer 39 by the voltage can be formed on the transparent electrode 36 (common electrode). Two types of small regions having different electric field directions are alternately formed at regular intervals along the width direction of the comb-shaped portions of the comb-shaped electrodes 35a and 35b (the left-right direction in FIG. 8B). Each small region has a stripe shape that is long in the direction perpendicular to the paper surface of FIG.

  As described above, the oblique electric fields 4 having different directions are generated alternately in the liquid crystal layer 39 corresponding to the comb-shaped electrodes 35a and 35b, and the liquid crystal molecules are controlled to tilt in the direction corresponding to the electric field direction. Thus, a multi-domain (two-domain) liquid crystal display element that can display different display contents depending on the viewing angle direction can be realized.

  FIG. 9 is a schematic plan view showing a part of segment electrodes (comb-like electrodes 35a and 35b) and a common electrode (transparent electrode 36) of a liquid crystal display device according to a modification of the liquid crystal display device according to the second embodiment. FIG. When compared with FIG. 8A, the formation mode of the slit 36a is different.

  In the transparent electrode 36 (common electrode) shown in FIG. 8A, the slit 36a is formed in a single stripe shape along the length direction of the comb-like portions of the comb-like electrodes 35a and 35b. It was. The slit 36a in the transparent electrode 36 (common electrode) shown in FIG. 9 is a slit in a form in which one stripe-shaped slit in FIG. 8A is bridged by a transparent electrode at the central portion of the slit. That is, a plurality of (two) short stripe-shaped slits 36a are formed in a straight line at predetermined positions of the transparent electrode 36 (common electrode).

  Even if the slit 36a is formed in the above-described manner, the same operation and effect as the liquid crystal display element according to the second embodiment described above can be obtained.

  In the formation mode of the slit 36a shown in FIG. 8A, since the electrodes are connected at two places above and below the slit 36a, it is necessary to secure a certain width of the connecting portion. However, in the formation mode shown in FIG. 9, since the electrode portion is bridged in the middle of the slit, the width of the upper and lower connecting portions can be reduced, and the electrode area of the connecting portion as a whole can be reduced. it can. Since an oblique electric field is not generated at the connecting portion, an effective display area can be widened. Furthermore, since it has a connection part other than two places on the upper and lower sides, the electrical characteristics of the electrode can be made uniform. It can also be expected to prevent accidents.

  Although FIG. 9 shows the slit 36a bridged at one place, a shorter slit bridged at a plurality of places may be formed.

  When the display of the liquid crystal display element according to the second embodiment and its modification was observed, different display contents in the left-right direction could be confirmed.

  The liquid crystal display element according to the third embodiment is a simple matrix type dot matrix type liquid crystal display element.

  FIG. 10A is a schematic plan view showing the segment electrodes 35c and 35d and the common electrode (transparent electrode 36) of the liquid crystal display element according to the third embodiment, and FIG. It is sectional drawing along the 10B-10B line of A). In FIG. 10B, not only the segment electrodes 35c and 35d and the transparent electrode 36 (common electrode), but also other constituent elements are shown.

  Reference is made to FIG. The liquid crystal display element according to the third embodiment has each display dot 81 formed by two bar-shaped segment electrodes 35c and 35d arranged substantially in parallel with each other and one bar-shaped transparent electrode 36 (common electrode) facing them. And the two segment electrodes 35c and 35d are routed to different terminals, and different drive signals (voltages) are applied by different voltage application means. The width of the transparent electrode 36 (common electrode) is wider than the width of the segment electrodes 35c and 35d.

  In order to form a large number of display dots 81, a large number of segment electrodes 35c and 35d and a large number of transparent electrodes 36 (common electrodes) are arranged substantially in parallel at a constant pitch. The segment electrodes 35c and the segment electrodes 35d are alternately arranged at equal intervals along a direction (width direction) orthogonal to the length direction of the electrodes. Further, the segment electrodes 35c and 35d and the transparent electrode 36 (common electrode) intersect each other when viewed from the normal direction of the substrate (the upper substrate 31 and the lower substrate 32) (perpendicular to the paper surface in FIG. 10A). For example, it arrange | positions so that it may orthogonally cross.

  Reference is made to FIG. A drive signal (voltage) is applied between one segment electrode 35c and the transparent electrode 36 (common electrode) by the voltage applying means 43c, and between the other segment electrode 35d and the transparent electrode 36 (common electrode). A driving signal (voltage) is given by the voltage applying means 43d.

  In the vertical alignment films 37 and 38, when viewed from the normal direction of the substrates 31 and 32 (vertical direction in FIG. 10B), for example, at positions corresponding to the segment electrodes 35c and 35d, A pretilt angle is given to a range that includes the segment electrodes 35c and 35d (or a range that includes at least a part of the segment electrodes 35c and 35d unless the inside or outside of the display dot 81 is concerned), and the liquid crystal molecules 39a are tilted in different directions. Two domains 80c, 80d (eg, opposite to each other) are formed. The domain 80c and the domain 80d are a region where the liquid crystal molecules 39a are tilted to the left side (region having a viewing angle on the right side in the figure) and a region where the liquid crystal molecules 39a are tilted to the right side (a region having a viewing angle on the left side in the figure). The domains 80c and 80d correspond to the formation positions of the segment electrode 35c and the segment electrode 35d, respectively, and are formed in stripes along their extending directions (in the direction perpendicular to the paper surface in FIG. 10B). The Both domains 80c and 80d are alternately arranged in the same width along the width direction of the segment electrodes 35c and 35d (the left-right direction in FIG. 10B).

  Since the liquid crystal display element according to the third embodiment has the above-described structure, each display dot 81 has a viewing angle direction opposite to each other, and a drive signal (voltage) that differs depending on the corresponding segment electrodes 35c and 35d. It includes two types of domains 80c and 80d that can be applied. For this reason, the liquid crystal display element according to the third embodiment can display two display contents having different viewing angle directions using each display dot 81.

  The pretilt angle can be given to the vertical alignment films 37 and 38 by using, for example, the photo-alignment process described in the first manufacturing method of the liquid crystal display element according to the first embodiment. In this embodiment (FIG. 10B), a pretilt angle is given to the vertical alignment films 37 and 38 of both substrates 31 and 32. However, a pretilt angle is applied to any of the vertical alignment films 37 and 38. And two domains 80c and 80d may be formed. In this case, it is possible to give a pretilt angle using the photo-alignment process described in the second or third manufacturing method of the first liquid crystal display element.

  In the liquid crystal display device according to the third embodiment, the transparent electrode 35 is formed as a group of rod-shaped segment electrodes 35c and 35d led to different terminals, and the transparent electrode 36 (common electrode (group)) intersects them. It differs from the method of manufacturing the liquid crystal display element according to the first embodiment in that it is formed in a rod shape and in that the two domains 80c and 80d are formed corresponding to the rod-shaped segment electrodes 35c and 35d, respectively.

  When the display of the liquid crystal display element according to the third example was observed, different display contents in the left-right direction could be confirmed.

  FIGS. 11A and 11B show display examples when the liquid crystal display element according to the third embodiment is viewed from the left direction and the right direction, respectively. As shown, it is possible to provide different displays to the left and right observers, for example, displays in different languages.

  The relationship between the liquid crystal display element according to the third embodiment and the liquid crystal display element according to the fourth embodiment is the same as the relationship between the first and second elements.

  In other words, the liquid crystal display element according to the fourth embodiment is the most different from the third embodiment in that a slit is provided at a predetermined position of the common electrode (transparent electrode 36). In the dot matrix type liquid crystal display element according to the third embodiment, at least one substrate (alignment film) is alternately formed with two types of regions provided with different pretilt angles in the liquid crystal layer 39. A two-domain structure was realized by using the generated vertical electric field. In the fourth embodiment, a two-domain structure is realized by using two-direction oblique electric fields generated between two sets of segment electrodes and a common electrode having a slit.

  For this reason, in the dot matrix type liquid crystal display element according to the fourth embodiment, the alignment film is not subjected to special alignment treatment such as provision of a pretilt angle. The liquid crystal display element according to the fourth embodiment is, for example, a liquid crystal display element that is subjected to a simple alignment process in which a vertical alignment film is applied and cured so as to cover a transparent electrode (segment electrode, common electrode) on a transparent substrate. It is. Further, an alignment film is not necessarily required.

  FIG. 12A is a schematic plan view showing a part of the segment electrodes 35c and 35d and the common electrode (transparent electrode 36) of the liquid crystal display element according to the fourth embodiment, and FIG. It is sectional drawing which followed the 12B-12B line | wire of FIG. FIG. 12A is a diagram corresponding to FIG. 10A in the third embodiment. In the liquid crystal display element according to the fourth embodiment, the segment electrodes 35e and 35f are formed in a bar shape wider in the width direction than the segment electrodes 35c and 35d in the third embodiment (FIG. 10A). Further, as described above, the difference is that the slit 36a is formed in the transparent electrode 36 (common electrode). In FIG. 12B, the transparent substrates 33 and 34 on which the segment electrodes 35e and 35f and the common electrode (transparent electrode 36) are formed are also shown.

  The liquid crystal display element according to the fourth embodiment corresponds to that according to the second embodiment in that the common electrode includes a slit. Accordingly, FIGS. 12A and 12B correspond to FIGS. 8A and 8B, respectively.

  Reference is made to FIG. Also in the liquid crystal display device according to the fourth embodiment, the two sets of segment electrodes 35e and 35f are routed to different terminals, and different drive signals (voltages) can be applied by different voltage applying means. The arrangement of the segment electrodes 35e and 35f and the transparent electrode 36 (common electrode) is the same as that in the third embodiment performed with reference to FIG.

  In the transparent electrode 36 (common electrode), for example, a plurality of congruent rectangular slits 36a are formed at a constant pitch in the length direction of the electrode. When viewed from the normal direction of the substrate (in the direction perpendicular to the paper surface in FIG. 12A), the slit 36a has a certain side edge in the length direction of one segment electrode 35e (FIG. 12A from the upper direction perpendicular to the paper surface). A right edge when viewed) and a constant edge in the length direction of the other segment electrode 35f facing it (the left edge when FIG. 12A is viewed from the upper side perpendicular to the paper surface). Be placed. In addition, the slit 36a is formed and arranged so that the edge of the slit 36a is located in the inner region of the adjacent segment electrodes 35e and 35f.

  Reference is made to FIG. For the same reason as in the case of the liquid crystal display element according to the second embodiment described with reference to FIG. 8B, a slit 36a is provided in the transparent electrode 36 (common electrode), so that a voltage is applied to the liquid crystal layer 39. The oblique electric field 4 can be generated in two directions opposite to each other with respect to the normal lines of the transparent substrates 33 and 34. In addition, a voltage applied between the one segment electrode 35e generates a slant electric field 4 in one direction in the liquid crystal layer 39 and a voltage applied between the other segment electrode 35f causes the liquid crystal layer 39 to A region for generating the oblique electric field 4 in the other direction can be formed on the transparent electrode 36 (common electrode). Two types of regions having different electric field directions are alternately formed in a stripe shape along the width direction of the segment electrodes 35e and 35f (the left-right direction in FIG. 12B).

  As described above, the oblique electric fields 4 having different directions are generated alternately in the liquid crystal layer 39 in correspondence with the segment electrodes 35e and 35f, and the liquid crystal molecules are controlled to be tilted in the direction corresponding to the electric field direction. A multi-domain (two-domain) liquid crystal display element capable of displaying different display contents depending on the viewing angle direction can be realized.

  When the display of the liquid crystal display element according to the fourth example was observed, different display contents could be confirmed in the left-right direction.

  Hereinafter, a suitable domain size (width of stripe domain) will be described.

  When a pretilt angle is imparted to the alignment film by photo-alignment processing as in the first and third embodiments, the domain can be produced in an arbitrary size. However, when the liquid crystal display element is formed with an excessively large domain, the domain itself is visually recognized, and it is difficult to obtain a good display. Therefore, the domain size (width of the stripe-shaped domain) is preferably 200 μm or less, and more preferably 100 μm or less. On the other hand, since the domain size (the width of the stripe-shaped domain) is also related to the electrode width, it is preferably 5 μm or more, and more preferably 10 μm or more, according to the demand for electrode pattern production.

  As in the second and fourth embodiments, in the liquid crystal display element in which the common electrode is provided with a slit and an oblique electric field is generated to change the alignment state of the liquid crystal, the effective range of the oblique electric field is limited. There is. Further, the large domain size (the width of the stripe domain) corresponds to the large width of the stripe pattern of the segment electrode and the long distance from end to end of the display portion. For this reason, if the domain size (the width of the stripe-shaped domain) is large, the reliability of the alignment control of the liquid crystal is reduced in the central portion away from the end of the display portion, and it becomes difficult to obtain a good two-domain alignment. As a result of repeated experiments by the inventors of the present application, a good two-domain alignment was obtained with a domain size (width of stripe-like domain) of 200 μm or less, and a better two-domain alignment was obtained with a domain size of 100 μm or less. The lower limit of the domain size (the width of the striped electrode) is preferably 5 μm or more, more preferably 10 μm or more, according to demands for electrode pattern production.

  In the embodiment, the liquid crystal display element of simple matrix drive is taken up. However, the present invention can also be applied to an active matrix drive liquid crystal display element such as a thin film transistor (TFT) drive.

Also when applied to active matrix driving, the basic configuration is the same as that of a dot matrix type liquid crystal display element of simple matrix driving. In the case of a simple matrix driving liquid crystal display element, the segment electrode is further divided into two stripe electrodes, and two-domain alignment is applied corresponding to each stripe electrode. However, in the case of an active matrix driving liquid crystal display element, As shown in FIG. 14, two sets of comb-like electrodes 83a and 83b (for example, the comb-like electrode 83a is a right viewing angle display electrode and the comb-like electrode 83b 2), and the substrate (alignment film) is subjected to two-domain alignment corresponding to each of the comb-like electrodes 83a and 83b. Since the TFTs 84a and 84b are provided corresponding to the two sets of comb-like electrodes 83a and 83b, respectively, the number of TFTs is twice as large as that of a normal active matrix driving liquid crystal display element. (For example, the TFT 84a is a right viewing angle display TFT corresponding to the comb-like electrode 83a, and the TFT 84b is a left viewing angle display TFT corresponding to the comb-like electrode 83b.)
In the embodiments, the vertical alignment type liquid crystal display element is described. However, the present invention can be applied to a TN type liquid crystal display element, an STN (Super Twisted Nematic) type liquid crystal display element, and a hybrid alignment type liquid crystal display element. it can.

In each type of liquid crystal display element, alignment treatment is performed by a mask rubbing method, a photo-alignment method, or the like, and liquid crystal molecules rise from the left and right sides (in some cases, the hybrid may fall down). In the case of a TN type or STN type liquid crystal display element, an oblique electric field by a slit can be used. However, in the case of a liquid crystal display element using a slit, the tilt angle of liquid crystal molecules in the center of the liquid crystal layer needs to be 0 ° (parallel to the substrate) in order to obtain a high-quality display.
Further, in the embodiment, two types of domains having different viewing angle directions (different alignment directions of liquid crystal molecules) are alternately formed in one direction (in a stripe shape), but are not necessarily formed alternately (in a stripe shape). May be. It is also possible to form two types of domains alternately in a plurality of directions, for example, in a checkered pattern.

  Further, in the embodiment, the liquid crystal display element in which the best viewing angle directions of the two domains are different by 180 ° is taken up, but it is not limited to 180 °. For example, when the pretilt angle is given by the photo-alignment process, the direction in which the pretilt angle is given may be freely selected.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

  It can be suitably used for a liquid crystal display element that can be viewed from different directions, particularly a liquid crystal display element that is installed in a place where the viewing angle direction is fixed, such as near the center console of an automobile.

It is a viewing angle characteristic view of a vertical alignment type liquid crystal display device having a two-domain structure (a two-domain structure including a domain having a viewing angle in the right direction and a domain having a viewing angle in the left direction). 1 is a schematic cross-sectional view illustrating an example of a vertical alignment type liquid crystal display element according to a first embodiment. It is a schematic top view which shows a part of segment electrode (comb-like transparent electrode 35a, 35b) and a common electrode (transparent electrode 36). (A)-(C) are schematic which shows an example of the display area of the liquid crystal display element by a 1st Example. (A)-(E) is the schematic for demonstrating the manufacturing method (1st manufacturing method) of the liquid crystal display element by a 1st Example which has a structure as shown in FIG. It is a schematic sectional drawing for demonstrating the 2nd manufacturing method of the liquid crystal display element by a 1st Example. (A)-(E) are schematic sectional drawings for demonstrating the 3rd manufacturing method of the liquid crystal display element by a 1st Example. FIG. 8A is a schematic plan view showing a part of segment electrodes (comb-like transparent electrodes 35a and 35b) and a common electrode (transparent electrode 36) of the liquid crystal display element according to the second embodiment. (B) is sectional drawing which followed the 8B-8B line | wire of FIG. 8 (A). It is a schematic plan view which shows a part of segment electrode (comb-like electrode 35a, 35b) and a common electrode (transparent electrode 36) of the liquid crystal display element which concerns on the modification of the liquid crystal display element by a 2nd Example. FIG. 10A is a schematic plan view showing segment electrodes 35c and 35d and a common electrode (transparent electrode 36) of the liquid crystal display element according to the third embodiment. FIG. 10B is a plan view of FIG. It is sectional drawing along line 10B-10B. (A) And (B) shows the example of a display at the time of seeing the liquid crystal display element by a 3rd Example from the left direction and the right direction, respectively. FIG. 12B is a schematic plan view showing a part of the segment electrodes 35c and 35d and the common electrode (transparent electrode 36) of the liquid crystal display element according to the fourth embodiment, and FIG. 12B is a schematic view of 12B in FIG. It is sectional drawing along the -12B line. It is sectional drawing which shows the prior art example of a liquid crystal display element (Liquid Crystal Display) of a vertical alignment type. It is a schematic plan view showing a part of an active matrix liquid crystal display element.

Explanation of symbols

4 oblique electric field 31 upper substrate 32 lower substrate 33, 34 transparent substrate 35, 36 transparent electrode 35a, b comb-tooth electrode 35c, d, e, f segment electrode 36a slit 37, 38 vertical alignment film 39 liquid crystal layer 39a liquid crystal molecule 40 Viewing angle compensation films 41, 42 Polarizing plates 43, 43a, b, c, d Voltage applying means 50 Vertical alignment type LCD
55, 56 Mask 55a, 56a Opening 55b, 56b Light-shielding part 80a, b, c, d Domain 81 Display dot 83a, b Comb-shaped electrode 84a, b TFT
α, β, γ, δ Small region

Claims (22)

A first transparent substrate and first and second electrodes formed on one surface of the first transparent substrate, the first and second electrodes being connected to and controlled by an independent electric circuit A first substrate including two electrodes;
A second substrate including a second transparent substrate and a third electrode formed on one surface of the second transparent substrate, wherein the first and second of the first substrate A second substrate disposed substantially parallel to the first substrate such that the surface on which the electrode is formed faces the surface on which the third electrode is formed;
A liquid crystal layer sandwiched between the first substrate and the second substrate, the liquid crystal being in a first direction when a voltage is applied between the first electrode and the third electrode; And a second portion where the liquid crystal falls in a second direction different from the first direction when a voltage is applied between the second electrode and the third electrode. A liquid crystal display element having a liquid crystal layer having a portion. 2. The liquid crystal display element according to claim 1, wherein the first portion and the second portion are alternately formed in at least one direction when viewed from the normal direction of the first and second substrates. . The liquid crystal display element according to claim 1, wherein the first direction and the second direction are opposite to each other with respect to a normal direction of the first and second substrates. Furthermore, the first substrate includes a first alignment film formed on the first transparent substrate so as to cover the first and second electrodes,
The second substrate includes a second alignment film formed on the second transparent substrate so as to cover the third electrode;
The first and second electrodes are both comb-like electrodes,
When viewed from the normal direction of the first and second substrates, the comb-like portion of the first electrode and the comb-like portion of the second electrode are along the width direction of the comb-like portion. The liquid crystal of the liquid crystal layer is disposed in a region including at least a part of the comb-like portion of the first electrode for at least one of the first or second alignment films. An alignment process is performed in which the liquid crystal layer is tilted in the second direction in an area including at least a part of the comb-like portion of the second electrode. The liquid crystal display element according to claim 1, wherein: Furthermore, the first substrate includes a first alignment film formed on the first transparent substrate so as to cover the first and second electrodes,
The second substrate includes a second alignment film formed on the second transparent substrate so as to cover the third electrode;
The first, second, and third electrodes are first, second, and third electrode groups that are long in one direction, respectively.
When viewed from the normal direction of the first and second substrates, each electrode of the first electrode group and each electrode of the second electrode group are in a direction orthogonal to the length direction of each electrode. And the first and second electrode groups and the third electrode group are arranged so as to intersect with each other, and at least one of the first and second alignment films is arranged. The region including at least a part of each electrode of the first electrode group is subjected to an alignment treatment for tilting the liquid crystal of the liquid crystal layer in the first direction. The liquid crystal display element according to claim 1, wherein a region including at least a part of each electrode is subjected to an alignment treatment for tilting the liquid crystal of the liquid crystal layer in the second direction. The liquid crystal display element according to claim 5, wherein the first and second electrode groups and the third electrode group are disposed so as to be orthogonal to each other. Furthermore, the third electrode includes a slit,
The first and second electrodes are both comb-like electrodes,
When viewed from the normal direction of the first and second substrates, the comb-like portion of the first electrode and the comb-like portion of the second electrode are along the width direction of the comb-like portion. The slits are arranged in the lengthwise direction of the comb-like portion of the first electrode and the lengthwise direction of the comb-like portion of the second electrode facing each other. Comb teeth that are formed so as to straddle the side edges and that extend along the length direction of the comb-like portions of the first and second electrodes are adjacent comb teeth of the first and second electrodes. The liquid crystal display element of any one of Claims 1-3 currently formed so that it may be located in the internal area | region of a shape-like part. The first, second, and third electrodes are first, second, and third electrode groups that are long in one direction, respectively, and each electrode of the third electrode group includes a slit,
When viewed from the normal direction of the first and second substrates, each electrode of the first electrode group and each electrode of the second electrode group are in a direction orthogonal to the length direction of each electrode. And the first and second electrode groups and the third electrode group are arranged so as to intersect with each other, and the slits are arranged in each of the first electrode groups. The electrodes of the first and second electrode groups are formed so as to straddle the constant side edges in the length direction of the electrodes and the constant side edges in the length direction of the electrodes of the opposing second electrode group. The edge of the said slit along the length direction of is formed so that it may be located in the internal area | region of the electrode which the said 1st and 2nd electrode group adjoins. Liquid crystal display element. The liquid crystal display element according to claim 8, wherein the first and second electrode groups and the third electrode group are arranged so as to be orthogonal to each other. (A) first and second films controlled by being connected to mutually independent electric circuits, each of which is a film of an alignment material sensitive to light and having the property of aligning liquid crystal molecules in a direction substantially perpendicular to the surface on average; Forming on a first substrate surface having a second electrode;
(B) forming a film of an alignment material on the second substrate surface having electrodes, which is sensitive to light and has a property of aligning liquid crystal molecules in a direction substantially perpendicular to the surface on average;
(C) Pre-tilt from vertical alignment by irradiating light from the direction inclined from the normal direction of the first and second substrates to the alignment material films formed on the surfaces of the first and second substrates, respectively. Forming two types of minute regions having different corners at positions corresponding to the formation positions of the first and second electrodes, respectively;
(D) A step of forming a liquid crystal layer between the first and second substrates by placing the first substrate and the second substrate facing each other with the surface on which the film of the alignment material is formed facing each other. The manufacturing method of the liquid crystal display element which has these. The step (c)
A portion of the alignment material film formed on the surface of the first substrate, the portion corresponding to one formation position of the first or second electrode, and a normal direction of the first substrate A first irradiation step of irradiating light from a first direction inclined from
A part of the alignment material film formed on the surface of the first substrate, corresponding to the other formation position of the first or second electrode, and irradiated with light in the first irradiation step. 11. A second irradiation step of irradiating a part of the film of the alignment material not irradiated with light from a second direction different from the first direction, which is inclined from a normal direction of the first substrate. The manufacturing method of the liquid crystal display element of description. The step (c)
A portion of the alignment material film formed on the surface of the second substrate, the portion corresponding to one formation position of the first or second electrode, and a normal direction of the second substrate A third irradiation step of irradiating light from a third direction inclined from
A part of the alignment material film formed on the surface of the second substrate, corresponding to the other formation position of the first or second electrode, and irradiated with light in the third irradiation step. 11. A fourth irradiation step of irradiating a part of the film of non-alignment material with light from a fourth direction that is inclined from a normal direction of the second substrate and is different from the third direction. Or a method for producing a liquid crystal display element according to 11; The method for manufacturing a liquid crystal display element according to claim 11, wherein the first direction and the second direction are symmetrical with respect to a normal direction of the first substrate. The method for manufacturing a liquid crystal display element according to claim 12, wherein the third direction and the fourth direction are symmetrical with respect to a normal direction of the second substrate. The alignment material film formed on the first and second substrate surfaces has a property of being sensitive to ultraviolet rays, and the alignment material formed on the first and second substrate surfaces in the step (c). The method for producing a liquid crystal display element according to claim 10, wherein the film is irradiated with ultraviolet rays. (A) forming a film of an alignment material on the first substrate surface having electrodes, which is sensitive to light and has a property of aligning liquid crystal molecules in a direction substantially perpendicular to the surface on average;
(B) Two kinds of microscopic materials having different pretilt angles from the vertical alignment are irradiated with light from a direction inclined from the normal direction of the first substrate to the alignment material film formed on the surface of the first substrate. Forming a region;
(C) forming a film of an alignment material having a property of aligning liquid crystal molecules in a direction substantially perpendicular to the surface on the average on the second substrate surface having electrodes;
(D) A step of forming a liquid crystal layer between the first and second substrates by placing the first substrate and the second substrate facing each other with the surface on which the film of the alignment material is formed facing each other. And
One of the electrode on the first substrate surface and the electrode on the second substrate surface includes first and second electrodes that are connected to and controlled by an independent electric circuit. ,
In the step (b), a method of manufacturing a liquid crystal display element, wherein two kinds of micro regions having different pretilt angles are formed at positions corresponding to the positions at which the first and second electrodes are formed, respectively. The step (b)
A first irradiation step of irradiating a part of the alignment material film formed on the surface of the first substrate with light from a first direction inclined from a normal direction of the first substrate;
The other part of the alignment material film formed on the surface of the first substrate and the other part of the alignment material film that is not irradiated with light in the first irradiation step may be The manufacturing method of the liquid crystal display element of Claim 16 including the 2nd irradiation process which inclines from the normal line direction of this board | substrate, and irradiates light from the 2nd direction different from the said 1st direction. The step (b)
A third irradiation step of irradiating light from a third direction inclined from a normal direction of the first substrate onto the film of the alignment material formed on the surface of the first substrate;
In the third irradiation step, a part of the alignment material film irradiated with light from the third direction is inclined from the normal direction of the first substrate, and is different from the third direction. The manufacturing method of the liquid crystal display element of Claim 16 including the 4th irradiation process of irradiating light from the direction of this. The method for manufacturing a liquid crystal display element according to claim 17, wherein the first direction and the second direction are symmetric with respect to a normal direction of the first substrate. The method for manufacturing a liquid crystal display element according to claim 18, wherein the third direction and the fourth direction are symmetric with respect to a normal direction of the first substrate. 21. The liquid crystal display according to claim 18 or 20, wherein a time for irradiating light from the fourth direction in the fourth irradiation step is longer than a time for irradiating light from the third direction in the third irradiation step. Device manufacturing method. The alignment material film formed on the surface of the first substrate is sensitive to ultraviolet rays. In the step (b), the alignment material film formed on the surface of the first substrate is irradiated with ultraviolet rays. The manufacturing method of the liquid crystal display element of Claims 16-21.

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