JP5274182B2 - Liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display which is able to make various presentations. <P>SOLUTION: This liquid crystal display includes a first transparent panel having a first electrode, a second transparent panel having a second electrode and disposed facing the first transparent panel with the second electrode facing the first electrode, and a liquid crystal layer sandwiched between the first and second transparent panels and having a number of areas different in thickness with its thickest area thicker than twice the thinnest area, and made of liquid crystal materials changing its scattered and transparent states by the voltage matching the thickness. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a liquid crystal display (LCD) .

  An invention of a liquid crystal display device has been disclosed in which a step on the substrate surface due to the presence or absence of an electrode is corrected by a difference in spacer diameter, and a gap in a display region is made uniform (see, for example, Patent Document 1). In the invention described in Patent Document 1, the diameters of spacers arranged inside and outside the display area are made different to eliminate steps of electrodes and color filters, thereby realizing uniform display.

  Display devices using polymer dispersed liquid crystal (PDLC) are known. In the production of a PDLC display element, a monomer having no liquid crystallinity in PDLC and a photoreaction initiator added are injected between the substrates, and ultraviolet rays are uniformly irradiated to form a liquid crystal layer. The monomer is polymerized by the irradiation of the ultraviolet rays, and the liquid crystal portion and the polymer portion of the liquid crystal layer are phase-separated (micro phase separation). Since the liquid crystal portion and the polymer portion have different refractive indexes, light incident on the liquid crystal layer when no voltage is applied is scattered (uniformly scattered). When a voltage is applied, the liquid crystal rises in the direction of the electric field, and the difference in refractive index between the liquid crystal and the polymer becomes small, so that the liquid crystal layer becomes transparent (see, for example, Patent Document 2).

  In a normal PDLC display element, it is possible to switch between uniform scattering and the transparent state over the entire liquid crystal layer, but controlling the scattering state depending on the location in the display region, for example, only a part of the display region is transparent It is difficult to make the surroundings in a scattering state and to change the place where the scattering state is caused by the applied voltage value.

  By providing a plurality of patterned electrodes and changing the voltage applied to each electrode, it is possible to form scattering states that differ to some extent depending on the location, but this method requires many electrodes and gradually It was impossible to display the expression obtained by changing the scattering state, for example, a natural change as if the glass surface was frozen.

  It is possible to express a natural change by generating a potential gradient using high-resistance ITO and effectively changing the voltage applied to the liquid crystal layer. However, it is difficult to form a high-resistance transparent conductive film that causes a potential gradient. For example, in order to make ITO more than 500Ω □, the film thickness needs to be 5 nm or less.

  When an electrode is originally formed of a high-resistance metal oxide film, there is a problem that patterning is difficult in addition to cost.

  By changing the particle size of the gap control agent added to the main sealant depending on the location, it is possible to realize a display in which ice is gradually stretched from right to left, for example. In addition, it may be possible to express an image that freezes from the surroundings by changing the particle size of the gap control agent added to the main sealant and the particle size of the gap control agent dispersed in the display area. However, with that method, more complicated expressions cannot be realized.

  Furthermore, a display element having a small liquid crystal cell size is likely to be affected by the main seal, but a liquid crystal display element having a large cell size has a problem that it is difficult to influence the main seal to the vicinity of the center of the liquid crystal cell. It was.

JP-A-5-241165 JP 2005-060703 A

  An object of the present invention is to provide a liquid crystal display element capable of various expressions.

According to an aspect of the present invention, the first transparent substrate including the first electrode and the second electrode are provided, and the first transparent substrate is provided so that the second electrode faces the first electrode. A second transparent substrate opposed to the substrate; a plurality of regions of different thickness sandwiched between the first transparent substrate and the second transparent substrate; the thickest region being the thinnest region has more than twice the thickness of saw including a liquid crystal layer formed of liquid crystal material and a transparent state and a scattering state at a voltage switched in accordance with the thickness, the liquid crystal layer, a polymer dispersion type liquid crystal or polymer The liquid crystal layer is configured to include a network liquid crystal, and the liquid crystal layer is disposed in a region surrounded by the seal portion between the first transparent substrate and the second transparent substrate. The first and second electrodes are solid electrodes, and the plurality of regions , The gap controller of a different size, a liquid crystal display device thickness is controlled is provided.

  According to the present invention, a liquid crystal display element capable of various expressions can be provided.

The invention according to the present invention, there is provided a liquid crystal display device that changes the scattering state of the device by a voltage applied, also the same voltage as was applied to the liquid crystal layer, related to the liquid crystal display elements having different scattering state occurs depending on the location. In this liquid crystal display element, by changing the applied voltage with time, the scattering state in the liquid crystal element can be changed according to location and time, and for example, a display that gradually freezes can be realized. Is possible.

  Hereinafter, the embodiment will be described in detail.

  1A to 1D are schematic views showing a method for manufacturing a liquid crystal display device according to the first embodiment. The method for manufacturing a liquid crystal display device according to the first embodiment is a method for manufacturing a liquid crystal display device using a gap control agent spraying method.

  Reference is made to FIG. An upper glass substrate 10 on which a transparent electrode 10a is formed and a lower glass substrate 20 on which a transparent electrode 20a is formed are prepared. The upper and lower glass substrates 10 and 20 are transparent substrates formed of, for example, blue plate glass having a thickness of 0.7 mm.

  The thicknesses of the upper and lower glass substrates 10 and 20 are not limited to this. Since the flexibility with respect to the thickness of a liquid crystal cell can be improved, the thinner one is preferable.

  The transparent electrodes 10a and 20a are ITO electrodes having a thickness of 100 to 2000 mm, for example, 2000 mm, and the electrode pattern is solid. Although partial patterning is performed so that no electrode pattern exists in the seal portion, a solid electrode is used for the light control portion (pixel portion, display area) of the liquid crystal display element.

  An alignment film is formed on the surfaces of the prepared transparent electrodes 10a and 20a of the pair of substrates 10 and 20 using a horizontal alignment film material, for example, SE-410 manufactured by Nissan Chemical Co., Ltd. The thickness of the alignment film is 50 to 100 nm, for example, 80 nm. Thereafter, alignment treatment is performed by rubbing or the like. The alignment process is performed, for example, so that the alignment direction between the upper and lower substrates is antiparallel. An alignment treatment may be performed so as to achieve twisted nematic alignment.

  Note that the alignment film formation and alignment treatment steps described above are not essential.

  Reference is made to FIG. On the lower substrate (the lower glass substrate 20 and the transparent electrode 20a), the main sealant 30 containing 2 to 10 wt%, for example, 4 wt% of the gap control agent is applied and formed. The main sealant 30 can be formed using screen printing or a dispenser. For example, ES-7500 manufactured by Mitsui Chemicals, Inc. is used as the sealing agent, and a plastic ball having a diameter of 75 μm is used as the gap control agent. A gap control agent having a diameter of 3 to 150 μm could be used.

  Further, a gap control agent is sprayed on the upper substrate (upper glass substrate 10 and transparent electrode 10a). It is possible to use a gap control agent with an adhesive, such as Micropearl (fixed type) manufactured by Sekisui Chemical Co., Ltd.

  First, a gap control agent having a diameter of 6 μm is sprayed on the entire upper substrate (the entire region corresponding to the inside of the main sealant 30). Next, plastic balls of 25 μm, 50 μm, 75 μm, and 100 μm are spread using a dry gap spreader in order from the smallest diameter through a mask formed of, for example, stainless steel (SUS).

  FIG. 1C is a schematic plan view of the masks 40 to 43 used for spraying the gap control agent. The masks 40 to 43 have the same size. Moreover, the opening parts 40a-43a of a mutually different shape are provided in a mutually different position.

  The mask 40 is disposed above the upper substrate, and a gap control agent having a diameter of 25 μm is spread on the upper substrate through the opening 40a. On the upper substrate, a gap control agent is dispersed in a region corresponding to the position and shape of the opening 40a.

  When spraying, the mask 40 is positioned and aligned so that the dotted line area in the figure becomes the display area of the liquid crystal display element defined inside the main sealant.

  When the spraying of the gap control agent having a diameter of 25 μm is completed, the mask 41 is placed on the upper substrate, and the gap control agent having a diameter of 50 μm is sprayed through the opening 41a. Thereby, a gap control agent is spread | dispersed in the area | region on the upper side board | substrate corresponding to the position and shape of the opening part 41a.

  Similarly, using a mask 42, a gap control agent having a diameter of 75 μm is sprayed through the opening 42a. Finally, using a mask 43, a gap control agent having a diameter of 100 μm is sprayed through the opening 43a.

  FIG. 1D shows a plan view of the upper substrate after the gap control agent has been dispersed. On the upper substrate, gap control agent application regions 40b to 43b corresponding to the positions and shapes of the openings 40a to 43a of the masks 40 to 43 are formed. Gap control agents having a diameter of 25 μm, 50 μm, 75 μm, and 100 μm are sprayed in the regions 40b, 41b, 42b, and 43b, respectively.

  When the gap control agent having a diameter of 6 μm to 100 μm has been sprayed, the upper substrate is subjected to heat treatment to adhere the gap control agent of each size to the substrate. The heat treatment is performed at 120 ° C. for 10 minutes, for example. Fixing by heat treatment can also be performed at each spraying. A gap control agent that is bonded by irradiation with ultraviolet light may be used.

  In addition, sectional drawing of the upper side board | substrate (upper side glass substrate 10 and the transparent electrode 10a) of FIG. 1 (B) is sectional drawing along the 1B-1B line | wire in this figure.

  In the above-described steps, the gap control agents of all sizes are fixed types, but non-fixed type gap control agents may be used particularly for those having a large diameter. Further, although the gap control agent having a diameter of 6 μm is sprayed on the entire surface of the substrate (the entire surface corresponding to the inside of the main sealant 30), it may be partially sprayed. However, the gap control agent is sprayed on the entire surface of the substrate (the entire surface corresponding to the inside of the main sealant 30) including the gap control agent of other diameters.

  The lower substrate (the lower glass substrate 20 and the transparent electrode 20a) on which the main sealant is applied is bonded to the upper substrate (the upper glass substrate 10 and the transparent electrode 10a) on which the gap control agent is dispersed. In bonding, the upper and lower substrates are overlapped, and heat treatment is performed in a state where a certain pressure is applied by a press machine or the like, and the main sealant 30 is cured. The heat treatment is performed at 150 ° C. for 30 minutes, for example.

  In this way, the thickness of the outer periphery (the main sealant coating formation portion) is 75 μm, and inside the main sealant, empty cells having different thicknesses are produced depending on the location.

  In the actual production of the present inventor, the movement of the gap control agent was observed when no fixed type gap control agent was used, when the empty cell was tilted, or in the liquid crystal injection process described below. In extreme cases, adhesion between the upper substrate and the lower substrate was also observed. When bonding between the upper and lower substrates occurs, not only does the bonded portion not perform the display function as a liquid crystal display element, but also a short circuit failure occurs on the entire surface due to the bonding, and the entire display portion may not be able to realize the display function. .

  From this, it is judged that it is preferable to use one or more types of gap control agents as the fixed type and to spread over the entire surface. In addition, it is desirable that the gap control agent sprayed on the entire surface has at least the smallest particle size among the plurality of gap control agents sprayed.

  Subsequently, a mixture of a liquid crystal, a photosensitive polymerizable monomer such as an acrylate monomer having no liquid crystallinity, and a photopolymerization initiator is vacuum-injected into the empty cell. As the liquid crystal material, for example, PNM-170 (refractive index anisotropy Δn = 0.226, dielectric anisotropy Δε> 0) manufactured by Dainippon Ink & Chemicals, Inc. can be used. An acrylate monomer having liquid crystallinity may be used.

  After the injection, an end sealant such as an epoxy two-component curing agent is applied to the injection port and sealed. The end sealant is not limited to this, but when an ultraviolet curable end sealant is used, light shielding is required so that light does not enter the cell.

Finally, the liquid crystal cell after the vacuum injection is irradiated with strong ultraviolet rays using, for example, a photo-alignment device manufactured by Mejiro Precision Co., Ltd. For example, ultraviolet light with a wavelength of 350 nm is irradiated at an intensity of 83 mW / cm ^{2 so} that the total exposure time is 30 seconds. In this case, the irradiation amount is 2.5 J / cm ² .

  The light source of the photo-alignment device manufactured by Mejiro Precision Co., Ltd. is a high-pressure mercury lamp, but ultraviolet light may be irradiated using a xenon lamp, a metal halide lamp, a low-pressure mercury lamp or the like.

  FIG. 2 shows an outline of the liquid crystal display device manufactured by the manufacturing method according to the first embodiment. In the liquid crystal display element, the liquid crystal cell has a different thickness depending on the location. The thickness of the liquid crystal layer 50 in the region where the 6 μm gap control agent is dispersed is about 6 μm. Further, the liquid crystal layer 50 at the position where the 25 μm gap control agent is dispersed has a thickness of about 25 μm. The liquid crystal layer 50 where the gap control agent having a diameter of 50 μm, 75 μm, and 100 μm is dispersed also has a thickness corresponding to the diameter of the gap control agent.

  As described above, the liquid crystal layer 50 of the liquid crystal display device manufactured by the manufacturing method according to the first embodiment has a thickness of 6 μm to 100 μm depending on the location. In addition, since the liquid crystal layer 50 is configured using a PDLC having a characteristic that the threshold value of the electro-optic characteristic changes according to the cell thickness, the threshold value for the scattering degree and voltage in the cell is set for each region having a different cell thickness. Can be changed. That is, by changing the voltage applied to the transparent electrodes 10a and 20a, the scattering state and the transparent state of the liquid crystal layer 50 can be switched and controlled for each place (for each region having a different thickness of the liquid crystal layer 50). . For this reason, there are few restrictions on a display pattern, and it is possible to realize various and expressive displays.

  By controlling the gap control agent diameter and the spraying area on the substrate in various ways, it has been difficult in the past, for example, a display in which only a part of the display area is transparent and the surroundings are in a scattering state. It is possible to easily realize a display in which the scattering state gradually changes, and a natural change display in which the glass surface is frozen.

  According to the manufacturing method according to the first embodiment, it is not necessary to use high-resistance ITO or a special drive circuit, and since the drive circuit can be made one, a liquid crystal display element is manufactured at a low cost. be able to.

  The maximum thickness (maximum diameter of the gap control agent) of the liquid crystal cell is 2 times or more, more preferably 5 times or more, more preferably 10 times or more, more preferably 20 times the minimum thickness (minimum diameter of the gap control agent). If it is above, the display excellent in the expressiveness will be realizable.

  In addition, by forming at least two, more preferably three or more, more preferably five or more, more preferably ten or more regions of different thicknesses in the liquid crystal cell, a variety of rich expressions can be realized. Let's go.

  FIG. 3 shows an example of a liquid crystal display element (liquid crystal cell) manufactured by a manufacturing method similar to the manufacturing method according to the first embodiment.

  The manufactured liquid crystal display element has a rectangular shape that is long in one direction (the left-right direction in the figure), and regions in which the thickness of the liquid crystal cell (the particle diameter of the gap control agent) varies along the length direction. In the liquid crystal cell shown in this figure, cell thickness regions of 100 μm, 75 μm, 50 μm, 25 μm, and 5 μm are formed in order from the left side of the drawing.

  FIG. 3 collectively shows four photographs when different voltages are applied to the rectangular liquid crystal cell. It is a photograph at the time of applying the voltage of 7V, 12V, 20V, and 30V in order from the top.

  Referring to the photograph of each liquid crystal cell, it can be seen that the liquid crystal cell has a scattering distribution according to the cell thickness depending on the location. In addition, when looking at the four photographs, it can be seen that as the applied voltage is increased (going downward in the figure), the transparent region increases from the thinner cell thickness (right side of the figure). .

  According to the inventor's visual observation, by applying a voltage to the liquid crystal cell, the thin part of the cell first becomes transparent, and as the voltage is increased, the thick part of the cell gradually becomes transparent. It was. When a very high voltage of about 30 V was applied, the entire cell surface became completely transparent. Furthermore, when the voltage was gradually decreased from this state, it was observed that the scattering gradually started from the thick part of the cell and the scattering state spread to the thin part of the cell. In other words, it was confirmed that the display gradually freezes in different states depending on the location.

  With reference to FIGS. 4A to 4F, another example of a liquid crystal display element (liquid crystal cell) manufactured by a manufacturing method similar to the manufacturing method according to the first embodiment will be described.

  FIG. 4A is a schematic plan view showing the in-plane thickness of the liquid crystal cell. A liquid crystal display element (liquid crystal cell) according to another example has a substantially square planar shape, and as shown in the figure, a triangular region having a thickness of 100 μm at the upper right and upper left corners and a thickness of 25 μm at the center. A crescent-shaped region having a thickness of 50 μm is formed in the lower left corner, and the cell thickness of the other portions is 75 μm.

  Reference is made to FIGS. 4B to 4F show appearance photographs when voltages of 2V, 7V, 12V, 20V, and 30V are sequentially applied to a liquid crystal cell according to another example, respectively.

  As in the case of the appearance photograph shown in FIG. 3, it is recognized that the liquid crystal cell has a scattering distribution according to the cell thickness depending on the location. In addition, it is recognized that as the applied voltage is increased, the transparent state starts from the region where the cell thickness is thin.

  5A to 5C show a liquid crystal display in which an effect illumination unit is added to still another example of the liquid crystal display element (liquid crystal cell) manufactured by the same manufacturing method as the manufacturing method according to the first embodiment. It is a photograph of an apparatus.

  In the illustrated liquid crystal display device, the light source is configured to allow light to enter from the lateral direction of the liquid crystal cell. A set of light emitting diodes of three colors, red, blue, and green, was arranged at six locations so that white light and color light could be irradiated. A reflective object such as a character or a picture, or a separate backlight may be arranged on the background (back side of the liquid crystal cell).

  FIGS. 5A, 5B, and 5C show cases where the applied voltages are 2V, 12V, and 30V, respectively. As the display moves from (A) to (B) and from (B) to (C), the display becomes clear. In this way, it is possible to realize an expression that gradually changes the clarity of display.

  The inventor of the present application measured the threshold value of the voltage at which the liquid crystal layer switches between the scattering state and the transparent state according to the cell thickness in the actually manufactured liquid crystal display element (liquid crystal cell). The voltage at which the light transmittance was about 10% (a state close to scattering) was about 1 V when the cell thickness was 5 μm, about 3 V when the cell thickness was 15 μm, about 6 V when 30 μm, and about 20 V when 75 μm. The voltage at which the light transmittance is about 90% (nearly transparent) is about 1.5 V when the cell thickness is 5 μm, about 4.5 V when the cell thickness is 15 μm, about 10 V when 30 μm, and about 10 V when the cell thickness is 75 μm. 30V.

  FIG. 6 is a table showing voltages for switching between the transparent state and the scattering state of the liquid crystal layer of the liquid crystal display device manufactured by the manufacturing method according to the first embodiment.

  For example, when a voltage of 5 V is applied to the liquid crystal layer, only the liquid crystal layer in the region where the gap control agent having a diameter of 6 μm is dispersed is made transparent, and the liquid crystal layers in the other regions (regions 40b to 43b in FIG. It can be in a scattering state.

  Further, by applying a voltage of 10 V, only the liquid crystal layer in the region where the gap control agent having a diameter of 6 μm and 25 μm is dispersed is made transparent, and the liquid crystal in the other regions (regions 41b to 43b in FIG. 1D). The layer can be in a scattering state.

  Further, for example, by applying a voltage of 15 V, the liquid crystal layer in the region in which the gap control agent having a diameter of 50 μm or less is dispersed is made transparent, and the liquid crystal layer in the other regions (regions 42b and 43b in FIG. 1D). Can be in a scattering state.

  When the applied voltage is 25 V, only the liquid crystal layer in the region 43b in which the gap control agent having a diameter of 100 μm is dispersed is set in a scattering state, and when a voltage of 30 V or more is applied, the liquid crystal layer on the entire display area is set in a transparent state. be able to.

  In this way, by changing the applied voltage, the display can be controlled by switching between the transparent state and the scattering state of each cell thickness portion.

  In addition, in the voltage between the voltage values shown in the table of FIG. 6, the scattering state changes in a halftone manner. Further, the scattering property (light reflectance) is substantially proportional to the logarithm of the cell thickness.

  7A to 7D are schematic views showing a method for manufacturing a liquid crystal display device according to the second embodiment. The method for manufacturing a liquid crystal display device according to the second embodiment is a method for manufacturing a liquid crystal display device using a one drop filling (ODF) method.

  Reference is made to FIG. An upper glass substrate 10 on which a transparent electrode 10a is formed and a lower glass substrate 20 on which a transparent electrode 20a is formed are prepared. The upper and lower glass substrates 10 and 20 are transparent substrates formed of, for example, blue plate glass having a thickness of 0.7 mm.

  The thicknesses of the upper and lower glass substrates 10 and 20 are not limited to this. Since the flexibility with respect to the thickness of a liquid crystal cell can be improved, the thinner one is preferable.

  The transparent electrodes 10a and 20a are ITO electrodes having a thickness of 100 to 2000 mm, for example 2000 mm. The electrode patterns of the transparent electrodes 10a and 20a on the upper and lower glass substrates 10 and 20 are solid. Although partial patterning is performed so that no electrode pattern exists in the seal portion, a solid electrode is used for the light control portion (pixel portion, display area) of the liquid crystal display element.

  An alignment film is formed on the surface of the transparent electrodes 10a and 20a of the prepared pair of substrates 10 and 20 using a horizontal alignment film material, for example, SE-610 manufactured by Nissan Chemical Co., Ltd. The alignment film is formed by, for example, a flexographic printing method. In addition, it is preferable that the surface energy of the horizontal alignment film material to be used is low, that is, the contact angle is high.

  The thickness of the alignment film is 50 to 100 nm, for example, 80 nm. Thereafter, alignment treatment is performed by rubbing or the like. The alignment process is performed, for example, so that the alignment direction between the upper and lower substrates is antiparallel. The heat treatment in the alignment treatment is performed at 230 ° C. for 1 hour, for example. An alignment treatment may be performed so as to achieve twisted nematic alignment.

  Note that the alignment film formation and alignment treatment steps described above are not essential.

  Reference is made to FIG. On the lower substrate (the lower glass substrate 20 and the transparent electrode 20a), the main sealant 30 containing 2 to 10 wt%, for example, 4 wt% of the gap control agent is applied and formed.

  For example, Photorec S manufactured by Sekisui Chemical Co., Ltd., which is a curable sealant with photothermal heat, is used as a sealant, and a plastic ball having a diameter of 75 μm is added to the sealant as a gap control agent. A gap control agent having a diameter of 3 to 150 μm could be used.

  Since the sealant has a high viscosity of, for example, about 400,000 mPa · s, it is appropriate to apply and form the main sealant 30 using a dispenser. The main sealant 30 is formed in a closed pattern having no inlet. Note that an outer peripheral seal pattern may be further formed outside the main sealant 30.

  Next, inside the seal pattern of the main sealant 30 on the lower substrate, a liquid crystal added with a gap control agent, a photosensitive polymerizable monomer, for example, an acrylate monomer having no liquid crystallinity, and a photopolymerization reaction initiator are mixed. Drop what you did. As the liquid crystal, for example, PNM-170 (refractive index anisotropy Δn = 0.226, dielectric anisotropy Δε> 0) manufactured by Dainippon Ink & Chemicals, Inc. is used. As a gap control agent added to the liquid crystal, for example, plastic balls having diameters of 6 μm, 25 μm, 50 μm, 75 μm, and 100 μm are used. Each liquid crystal to which the gap control agent of each particle size is added is dropped at different predetermined positions on the lower substrate. As the acrylate monomer, one having liquid crystallinity may be used.

The added concentration of the gap control agent varies depending on the diameter of the gap control agent. For example, if the gap controller of 6μm diameter, mixed at a ratio of 0.11 wt% in the liquid crystal (about 10 million per crystal 1g, cell dispersion amount 100 / mm ^2). The liquid crystal to which the gap control agent is added is dropped after stirring and defoaming. Further, in the case of a gap control agent having a diameter of 100 μm, 5.2 wt% (about 100,000 per 1 g of liquid crystal, dispersion amount in cell 10 / mm ² ) is added to the liquid crystal, and after stirring and defoaming, dropwise addition is performed. Do.

  For example, since the gap control agent having a diameter of 100 μm has a large specific gravity, even if it is stirred for a long time, it tends to precipitate at the bottom of the liquid crystal as time passes. Therefore, it is desirable to drop the liquid crystal using a syringe with a stirring function, for example. A syringe with a stirring function is preferably used for dropping liquid crystal to which a gap control agent having a particle size of about 10 μm or more is added.

  The amount of liquid crystal containing the gap control agent is the volume obtained by multiplying the area of the area to be the cell thickness (the cell thickness at the liquid crystal dropping position determined by the diameter of the gap control agent, etc.) by the cell thickness. The volume is several percent smaller.

  The liquid crystal is preferably dropped in order from the smaller diameter of the added gap control agent. This is because the liquid crystal having a larger diameter of the gap control agent is more easily spread.

  FIG. 7C shows a plan view of the lower substrate after the application and formation of the main sealant 30 and the dropping of the liquid crystal added with the gap control agent are completed. Liquid crystal to which a gap control agent having a diameter of 25 μm, 50 μm, 75 μm, and 100 μm is added is dropped in the regions 40b, 41b, 42b, and 43b, respectively. Liquid crystal containing a 6 μm-diameter gap control agent is dropped on other regions inside the main sealant 30.

  Note that the cross-sectional view of the lower substrate (the lower glass substrate 20 and the transparent electrode 20a) in FIG. 7B is a cross-sectional view taken along line 7B-7B in this drawing.

  Reference is made to FIG. The upper and lower substrates are bonded together using a vacuum overlay apparatus. The upper glass substrate 10 and the lower glass substrate 20 are held such that the surfaces on which the transparent electrodes 10a and 20a are formed face each other, and evacuation is performed. The lower glass substrate 20 is placed below, and the upper glass substrate 10 is placed on top using mechanical pins or electrostatic attraction to prevent dropping.

  When a predetermined degree of vacuum is reached, the upper and lower substrates are aligned at a predetermined position while maintaining a certain distance, and thereafter, the distance between the two substrates is gradually brought closer to perform superposition. When the distance between the two substrates is equal to or less than the height of the main seal or an outer peripheral seal is formed on the outside of the main seal, the substrates are brought into close contact with each other when released to atmospheric pressure when approaching the height or less.

  In addition, when a part of the seal part or the outer peripheral seal part is formed so as not to deviate from the aligned position at the time of superposition, the part may be irradiated with ultraviolet light. However, there is little slippage due to the high viscosity of the sealant. For this reason, it is not an essential process.

  In addition, it is desirable that the substrates be bonded immediately after the liquid crystal is dropped. This is because the liquid crystal spreads over time and may contact with the sealant before curing to form defects.

  In the method of manufacturing the liquid crystal display element according to the second embodiment, an alignment film is formed using SE-610 manufactured by Nissan Chemical Co., Ltd., which is a horizontal alignment film material having a low surface energy (high contact angle). Therefore, the dropped liquid crystal does not diffuse rapidly. Nevertheless, since a desired cell thickness distribution may not be obtained or display defects may occur, it is desirable to bond within 30 minutes after dropping. From the viewpoint of bonding time and the like, it is preferable to form the alignment film using a horizontal alignment film material having a surface energy of 42 dyn / cm or less.

  The distance between the substrates after bonding is determined by the diameter of the gap control agent distributed in different sizes depending on the location, the diameter of the gap control agent mixed in the main sealant, and the amount of liquid crystal dropped. In particular, the diameter of the gap control agent distributed in different sizes depending on the location has a strong influence, thereby forming a plurality of regions having different cell thicknesses depending on the location.

  In each of these regions, the thickness of the central portion of the region is approximately equal to the diameter of the gap control agent contained. Further, the thickness of the boundary between two regions adjacent to each other is an intermediate thickness between the thicknesses of the central portions of the regions sandwiching the boundary line.

Subsequently, ultraviolet light is irradiated to the entire upper and lower substrates to simultaneously perform temporary curing of the main sealant 30 and polymerization of monomers in the liquid crystal. In the irradiation, for example, an ultraviolet irradiator manufactured by USHIO INC. Is used, and the total exposure is set to 3 J / cm ² .

  Finally, heat treatment is performed in an oven at 120 ° C. for 60 minutes to fully cure the main sealant.

  The liquid crystal display element manufactured by the manufacturing method according to the second embodiment also has the same structure and function as the liquid crystal display element manufactured by the manufacturing method according to the first embodiment, and has the same effects.

  In addition, since the method of manufacturing the liquid crystal display element according to the second embodiment uses ODF, the cost can be reduced. Furthermore, since an end seal is unnecessary, a highly reliable liquid crystal display element can be manufactured.

  Also for the liquid crystal display device manufactured by the manufacturing method according to the second embodiment, the maximum thickness (maximum diameter of the gap control agent) of the liquid crystal cell is more than twice the minimum thickness (minimum diameter of the gap control agent). If it is preferably 5 times or more, more preferably 10 times or more, and even more preferably 20 times or more, a display with excellent expression can be realized.

  In addition, by forming at least two, more preferably three or more, more preferably five or more, more preferably ten or more regions of different thicknesses in the liquid crystal cell, a variety of rich expressions can be realized. Let's go.

  As mentioned above, although this invention was demonstrated along the Example and the modification, this invention is not limited to these.

  For example, in the manufacturing method according to the first embodiment, the gap control agent is sprayed on the upper substrate and the main sealant is applied and formed on the lower substrate, but the substrate on which the gap control agent is sprayed and the main sealant are formed. The substrates can be the same substrate.

  In the embodiment, the liquid crystal layer is formed by using PDLC. However, for example, polymer network liquid crystal (PNLC) can be used. PNLC, like PDLC, is a liquid crystal material having a characteristic that the threshold value of electro-optical characteristics changes according to the cell thickness.

  Further, in the examples, the diameter of the gap control agent added to the main sealant is single (75 μm), but the particle size of the gap control agent mixed into the main sealant may be changed depending on the location.

  Further, the ultraviolet irradiation conditions (first exposed portion) can be changed. Thereby, it is possible to change the scattering state in a cell according to a place.

  A mask may be used at the time of ultraviolet irradiation, or the cell may be inclined.

  It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like are possible.

  For example, it can be suitably used for various lighting display devices such as display devices for presentation of gaming machines such as pachinko and pachislot machines, display devices mounted on automobiles, general lighting, and vending machines.

(A)-(D) are schematic which shows the manufacturing method of the liquid crystal display element by a 1st Example. It is the schematic of the liquid crystal display element manufactured with the manufacturing method by a 1st Example. It is an external appearance photograph of an example of the liquid crystal display element (liquid crystal cell) manufactured with the manufacturing method similar to the manufacturing method by a 1st Example. (A)-(F) are the schematic and the photograph explaining the other example of the liquid crystal display element (liquid crystal cell) manufactured with the manufacturing method similar to the manufacturing method by a 1st Example. (A)-(C) is a liquid crystal display device in which an effect illumination unit is added to still another example of a liquid crystal display element (liquid crystal cell) manufactured by the same manufacturing method as the manufacturing method according to the first embodiment. It is a photograph. It is a table | surface which shows the voltage which switches the transparent state of a liquid crystal layer of the liquid crystal display element manufactured with the manufacturing method by a 1st Example, and a scattering state. (A)-(D) are schematic which shows the manufacturing method of the liquid crystal display element by a 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Upper glass substrate 20 Lower glass substrate 10a, 20a Transparent electrode 30 Main sealant 40-43 Mask 40a-43a Opening 40b-43b Area | region 50 Liquid crystal layer

Claims (1)

A first transparent substrate comprising a first electrode;
A second transparent substrate including a second electrode, the second transparent substrate disposed opposite to the first transparent substrate so that the second electrode faces the first electrode;
A plurality of regions having different thicknesses are sandwiched between the first transparent substrate and the second transparent substrate, and the thickest region has a thickness more than twice that of the thinnest region. voltage seen including a liquid crystal layer formed of liquid crystal material and the scattering state and the transparent state is switched in accordance with,
The liquid crystal layer includes a polymer dispersed liquid crystal or a polymer network liquid crystal,
The liquid crystal layer is disposed in a region surrounded by a seal portion between the first transparent substrate and the second transparent substrate, and the thickness of the seal portion varies depending on the location,
The first and second electrodes are solid electrodes;
The plurality of regions are liquid crystal display elements in which thicknesses are controlled by gap control agents having different sizes .