JP3791224B2 - REFLECTIVE LIQUID CRYSTAL DEVICE, ITS MANUFACTURING METHOD, AND ELECTRONIC DEVICE - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reflective liquid crystal device and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, as a reflective liquid crystal device, a liquid crystal cell in which a liquid crystal layer is sealed between a transparent front side substrate and a back side substrate is provided, and a reflective layer is formed on the inner surface of the back side substrate. Proposed. When the reflective layer is formed on the inner surface of the back side substrate in this way, the external light that has passed through the front side substrate and has entered the liquid crystal layer is reflected by the reflective layer, and again the liquid crystal layer and the front side substrate. Passing through the eyes of the viewer. There are various types of reflection type liquid crystal devices depending on the liquid crystal control method.
[0003]
For example, in a method called TN type or STN type, a polarizing plate is arranged before and after the liquid crystal cell, and the polarization state of light is changed when passing through the liquid crystal layer, thereby displaying depending on whether light passes through the polarizing plate or not. Is to do. However, in this method, since it is necessary to dispose the polarizing plate between the liquid crystal layer and the reflective layer, in general, the polarizing plate is stuck on the outer surface of the back side substrate, and further, the outer surface of the polarizing plate A reflector is attached to the top.
[0004]
On the other hand, one polarizing plate is sufficient, such as a single polarizing plate method (SPD: single polarizing plate device), a guest-host method (GH liquid crystal), a polymer dispersed liquid crystal (PDLC), etc. Some do not require a polarizing plate at all. In general, it is not necessary to use a polarizing plate in the case of a method for controlling the change in the color tone of the dichroic dye in the liquid crystal layer, the presence or absence of light scattering in the liquid crystal layer, and the like. In such a case, since the light is not absorbed by the polarizing plate, the display can be brightened. In the method using only one polarizing plate as described above, or in the method using no polarizing plate, the reflective layer can be formed on the inner surface of the back substrate, which is caused in the case of the two polarizing plate method. It is possible to prevent double display of display, display blur, and color mixing.
[0005]
In various reflective liquid crystal devices in which a reflective layer is formed on the inner surface of the back substrate as described above, external light is reflected by the surface of the reflective layer and used as light for visually recognizing display. In order to improve, it is necessary to impart light diffusibility or scattering to the reflecting surface. For example, in the case of a liquid crystal device using a single-polarizing plate method or a guest-host effect, white can be displayed by scattering of light on the reflecting surface and the viewing angle characteristics can be widened. Therefore, it is necessary to have an uneven shape on the reflecting surface that scatters the reflected light and suppresses a decrease in brightness as much as possible. In addition, in the case of a polymer dispersion type liquid crystal device in which the liquid crystal layer itself has a scattering mode, black is displayed when the liquid crystal layer is in a light transmitting state. At this time, the background, illumination, etc. are reflected on the reflecting surface. As a result, the display quality of the liquid crystal screen may be significantly deteriorated. Therefore, it is necessary to form a gentle concavo-convex structure on the surface of the reflective surface to moderate regular reflection (direct reflection).
[0006]
[Problems to be solved by the invention]
By the way, the rough surface or the uneven shape of the reflection surface is formed by a method of roughening the surface of the reflection layer or forming a resin layer having a surface uneven structure as a base layer of the reflection layer. As a method for roughening the surface of the reflective layer, there are etching and blasting. However, it is difficult to control optical characteristics with a scattering surface obtained by these methods. In particular, as can be seen from the slightly different optical characteristics of the reflecting surface required by the liquid crystal device system as described above, in order to improve the display quality of each liquid crystal device, precisely controlled light is scattered. It is necessary to build in the structure. However, the above manufacturing method cannot form a structure for scattering high-precision light.
[0007]
On the other hand, the method of forming the uneven surface of the resin layer and depositing the reflective film thereon can form the uneven surface of the reflective surface with relatively good controllability, as disclosed in JP-A-9-258219. The specific means is described. However, in this method, in order to obtain a good concavo-convex shape and shape, a photolithographic process including coating, baking, exposure, and development of a photosensitive material for forming a resin layer on the inner surface of the back substrate is performed. In addition, a heating process that melts the resin layer is performed, and a polymer resin layer is coated again on this resin layer, and a reflective layer is formed thereon. There is a problem that the manufacturing cost is increased while the performance and the yield are lowered. Also for the application of the photosensitive material, in order to obtain a scattering structure, it is necessary to form a film that is considerably thick and uniform, which is a very difficult process to control.
[0008]
Therefore, the present invention solves the above-described problems, and the problem is a method for obtaining the uneven shape of the reflective surface in the manufacturing process of the reflective liquid crystal device, and the uneven surface shape can be easily and accurately obtained. An object of the present invention is to provide a method that can be formed, can be improved in productivity, can improve the yield of products, and can reduce manufacturing costs.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention has taken measures to form a resin layer having unevenness on one of the pair of substrates in a reflective liquid crystal device in which a liquid crystal layer is sandwiched between the pair of substrates. Is Wait The The resin layer is formed by transferring a resin layer having an uneven shape on the surface onto the one substrate, A reflection layer is formed on the resin layer.
[0010]
With such a configuration, it is possible to easily form a reflective layer having an uneven surface and to obtain desired light scattering characteristics by controlling the unevenness of the transfer sheet.
[0011]
Furthermore, the resin layer is formed of a resin sheet, and is formed on the surface of the one substrate on the liquid crystal layer side. The resin layer is made of a photosensitive resin.
[0012]
The manufacturing method of such a liquid crystal device is as follows. That is, In a manufacturing method of a reflective liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates, the surface has an uneven shape. Transfer sheet made of resin layer The liquid Transfer on one substrate of crystallizer And forming a resin layer having irregularities on the one substrate; A reflective layer is formed on the surface of the resin layer Process It is characterized by that.
[0013]
According to this means, by transferring a resin layer previously formed on the transfer sheet onto the inner surface of the substrate and forming a reflective layer thereon, the surface shape of the reflective layer is separated from the production line of the liquid crystal device. Since a resin layer forming step can be provided for prescribing the resin layer, it is not necessary to form the resin layer on the substrate, the production efficiency can be improved, and the resin layer can be formed in any area at another location. Therefore, the resin layer can be formed more easily and at low cost.
[0014]
Here, it is preferable that a predetermined uneven shape is formed on the surface of the resin layer before transfer to the substrate.
[0015]
According to this means, a resin layer having a concavo-convex shape is formed in advance on the transfer sheet made of the resin layer, and this resin layer is transferred onto the substrate. Since the resin layer can be completed, the production efficiency and the yield can be improved, and the resin layer can be configured without any restrictions due to the structure of the substrate, so that the desired high shape can be achieved more easily and at low cost. It becomes possible to form an uneven shape having accuracy. In this case, as a method for forming an uneven shape on the surface of the resin layer, in addition to a method such as embossing as will be described later, the resin layer is made of a photosensitive resin, mask exposure is performed, and the unevenness is formed using a photolithography method. A shape can also be formed.
[0016]
In this case, the resin layer is preferably made of a photosensitive resin.
[0017]
According to this means, it is possible to form the resin layer by exposing and developing the resin layer itself when the uneven shape of the resin layer is formed and / or when the resin layer is patterned. The resin layer is preferably made of a material exhibiting adhesiveness or softening property that can be adhered to the back side substrate at a predetermined temperature or lower. In particular, when heating or pressing is performed at the time of transfer to the substrate, it is desirable that the material can obtain a sufficient adhesion to the substrate by a practical level of heating or pressing.
[0018]
The uneven shape of the resin layer is preferably formed by embossing.
[0019]
According to this means, the surface of the resin layer can be pressed with a mold roller, a mold plate, or the like to be molded into a desired shape and cured to form a concavo-convex shape easily and at low cost. In this case, since the resin layer is in a film state at the unevenness forming stage, it can be easily embossed.
[0020]
Furthermore, it is desirable that the uneven shape of the resin layer is formed by including fine particles dispersed in the layer.
[0021]
According to this means, for example, by applying a resin in which fine particles are dispersed, or by applying a resin in a place where fine particles are dispersed and arranged, the shape of the fine particles is applied to the surface of the resin layer. Since the uneven shape is automatically formed and the uneven height and plane pitch of the uneven shape can be adjusted according to the particle size and dispersion degree of the fine particles, the uneven shape can be formed easily and at low cost.
[0022]
Furthermore, it is desirable to form an uneven shape on the surface of the resin layer by photolithography before transferring the resin layer.
[0023]
Also in this case, steps such as exposure and development can be performed while the resin is in the form of a sheet, so that the steps can be simplified and the concavo-convex structure can be formed with high accuracy.
[0024]
Moreover, it is preferable to form an uneven shape on the surface of the resin layer by a photolithography method after the resin layer is formed of a photosensitive resin and the resin layer is transferred onto the substrate.
[0025]
Also in this case, since the thick coating of the resin layer onto the substrate, which has been difficult in the past, can be performed by a simple method of transferring the sheet, the manufacturing process is simplified and the film thickness is uniform. A resin layer can be formed.
[0026]
In each of the above means, the transfer sheet is composed of the resin layer and a protective support laminated on the surface thereof, and after being transferred onto the substrate, the protective support is removed, and then the reflective surface Is preferably formed.
[0027]
As a result, the resin surface to be transferred is protected in the transfer step, which can contribute to an improvement in the yield of this step.
[0028]
In each of the above means, the resin layer is preferably laminated on a temporary support, and the temporary support is removed to transfer the resin layer.
[0029]
According to this means, after the resin layer is formed on the temporary support, the uneven shape can be formed, so that the transfer sheet can be easily formed.
[0030]
Furthermore, in each of the above means, it is desirable to form a buffer layer configured to exhibit flexibility at least during transfer between the resin layer and the protective support.
[0031]
According to this means, even if there is an uneven shape on the surface of the substrate, it is possible to apply a uniform stress to the resin due to the flexibility of the buffer layer at the time of transfer. Can be transferred with.
[0032]
The buffer layer has characteristics that can be easily and selectively removed later, and characteristics that can be easily deformed during transfer (especially when transferring by heating or pressurization, it can be easily deformed by heating and pressurization and uniformly It is desirable that the resin layer has a characteristic capable of pressing the resin layer. Furthermore, it is more desirable to improve the storability of the transfer sheet by forming an intermediate layer having low oxygen permeability while ensuring mutual adhesion between the resin layer and the buffer layer.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is an enlarged longitudinal sectional view of a reflective liquid crystal device formed according to this embodiment.
[0034]
A transparent electrode 11 made of a transparent conductive film made of ITO (Indium Tin Oxide) is formed on the inner surface of a transparent front side substrate 10 made of inorganic glass or the like, and a transparent electrode made of polyimide or polyvinyl alcohol is formed thereon. An alignment film 12 is formed. The alignment film 12 is rubbed in a predetermined direction as necessary.
[0035]
On the other hand, a resin layer 21 is attached on the inner surface of the substrate 20 on the back side, and a fine uneven shape 21 a is formed on the surface of the resin layer 21. A reflective electrode 22 made of a reflective or conductive material such as Al or Cr is deposited on the surface of the resin layer 21. The reflective electrode 22 is made of a transparent resin made of the same material as the alignment film 12. An alignment film 23 is formed by coating. The alignment film 23 is also rubbed in a predetermined direction. In this case, as shown in the drawing, the alignment film 23 can be formed to have a thickness that allows the surface of the reflective electrode 22 to be almost flattened by filling the uneven shape of the surface of the reflective electrode 22 in order to suppress alignment defects due to the surface unevenness. . Further, after another planarizing layer made of a transparent resin or the like is formed on the reflective electrode 22, the alignment film 23 may be deposited.
[0036]
As described above, a transparent resin can be used as the planarizing layer, but an insulating film made of polysilazane can also be formed. A solvent made of polysilazane is applied so that the film thickness is uniform over the entire surface of the substrate. Thereafter, the applied solvent is baked to form an insulating film. By forming such an insulating film between the alignment film and the electrode, it is possible to obtain a liquid crystal device in which the surface of the substrate on the liquid crystal layer side is flat and there is no difference in the thickness of the liquid crystal layer. Accordingly, a display defect due to a difference in the thickness of the liquid crystal layer, and further, a defect due to rubbing is improved because the substrate is not uneven, and a liquid crystal device having excellent display characteristics can be obtained.
[0037]
The front-side substrate 10 and the back-side substrate 20 formed as described above are bonded to each other with a predetermined interval through a sealing material (not shown), and liquid crystal is injected between the two substrates, thereby liquid crystal layer 30. Is formed. The liquid crystal layer 30 is configured with an appropriate liquid crystal composition depending on the type, such as a single-polarizing plate type liquid crystal device utilizing the birefringence of liquid crystal, a guest-host type liquid crystal device, and a polymer dispersion type liquid crystal device.
[0038]
In the case of the present embodiment, it is possible to adopt a single-reflection plate type liquid crystal layer that uses a TN liquid crystal having a predetermined twist angle and performs passage and blocking of reflected light by birefringence of the liquid crystal layer. it can. In this case, a polarizing plate is disposed on the front side of the liquid crystal cell. The external light passes through the polarizing plate to become linearly polarized light, passes through the liquid crystal layer 30 in the state where no electric field is applied, becomes circularly polarized light on the reflecting surface, and after being reflected, passes again through the liquid crystal layer 30 and returns to the original linearly polarized light. Therefore, the light cannot be transmitted through the polarizing plate. On the other hand, when an electric field is applied to the liquid crystal layer 30, the influence on the polarization state of linearly polarized light changes, and the linearly polarized light is again reflected on the reflecting surface. It becomes a linearly polarized light almost equal to and can pass through the polarizing plate.
[0039]
Conversely, the twist angle in the liquid crystal layer, the thickness of the liquid crystal layer, the relationship between the polarization axis of the polarizing plate and the rubbing direction applied to the substrate adjacent to the reflective layer, and at least one disposed so that the reflective layer becomes linearly polarized light. It is also possible to set a relationship with a single phase difference plate.
[0040]
As the liquid crystal layer 30 in this case, a nematic liquid crystal layer having a twist angle of 60 to 270 degrees can be used. In order to adjust the degree of influence on the polarization state by the birefringence of the liquid crystal layer 30 as described above, it is necessary to adjust the retardation Δnd of the liquid crystal layer. In some cases, a phase difference plate may be disposed between the polarizing plate and the liquid crystal cell in order to compensate for the wavelength dispersion of light. At least one retardation plate is disposed, but two or more retardation plates can be provided in consideration of viewing angle compensation.
[0041]
In the present embodiment, a light scattering type liquid crystal layer that uses a light scattering state and a light transmission state for display may be employed. The liquid crystal layer 30 of the present embodiment is preferably a so-called polymer-dispersed liquid crystal among such liquid crystal layers. The liquid crystal layer 30 has liquid crystal molecules and polymers dispersed in each other. Yes. In this case, the polymer particles are dispersed in the liquid crystal, the liquid crystal layer is arranged so that a large amount of polymer particles are connected, the gel-like polymer network skeleton There are various modes such as those in which liquid crystal is contained in the liquid crystal, and liquid crystal droplets dispersed in a polymer.
[0042]
In this embodiment, after injecting a solution in which a liquid crystal and a polymer precursor that can be polymerized with light or an electron beam are compatible into an empty cell, irradiation with light or an electron beam is performed. The liquid crystal layer 30 can be formed by polymerizing a molecular precursor and precipitating a polymer in the liquid crystal by phase separation. As the liquid crystal, various liquid crystals can be used as long as they have dielectric anisotropy and refractive index anisotropy. Here, when the liquid crystal has positive dielectric anisotropy, the liquid crystal is horizontally aligned by rubbing the substrate surface, and when the liquid crystal has negative dielectric anisotropy, the liquid crystal is vertically aligned. It is preferable. In particular, when the liquid crystal layer is formed by this method, both the liquid crystal and the polymer can be aligned in a predetermined direction.
[0043]
As the polymer precursor, a photopolymerizable compound such as biphenyl methacrylate, other methacrylates, acrylates and other vinyl compounds, or a thermopolymerizable compound such as an epoxy compound can be used. About a thermopolymerizable compound, a polymer can be phase-separated by heating to an appropriate temperature. In addition, a thermoplastic compound such as ethyl cellulose can be used as the polymer. In this case, the polymer is phase-separated by mixing with liquid crystal in a heated state and then injecting into an empty cell and cooling. be able to. Note that the display contrast and viewing angle dependency can be improved by mixing a chiral component in the liquid crystal component.
[0044]
As an example of forming the polymer-dispersed liquid crystal layer 30 of the present embodiment, for example, 90 wt% “BL007” (trade name) manufactured by Merck is used as the liquid crystal and “CB15” (product manufactured by Merck is used as the chiral component) Name) was prepared by mixing 3 wt% and 7 wt% of biphenyl methacrylate as a polymer precursor, and this solution was used to form a front-side substrate 10, a back-side substrate 20, and a gap between substrates consisting of a sealing material of about 5 microns. After injecting into an empty cell and sealing, ultraviolet rays are irradiated to phase-separate polymer particles in the liquid crystal. If the irradiation amount of ultraviolet rays is set appropriately, the drive voltage becomes about 5 volts, and the watch IC can be sufficiently driven. In such a method for forming a liquid crystal layer, the drive voltage and the display mode can be set within a practical range by the ratio of the liquid crystal component being about 50 to 95 wt%.
[0045]
In the liquid crystal layer 30 of the present embodiment, when no electric field is applied, the liquid crystal and the polymer particles in the liquid crystal layer are both aligned horizontally, and the refractive index of the liquid crystal and the polymer particles is almost equal, so that the light transmission state become. On the other hand, when an electric field exceeding a predetermined threshold is applied, the liquid crystal having dielectric anisotropy is vertically aligned in the region where the electric field is applied, and the liquid crystal also has refractive index anisotropy. A difference occurs between the refractive index of the polymer and a light scattering state occurs.
[0046]
For this reason, it can be made cloudy by applying a voltage exceeding a threshold value to a region corresponding to the display contents such as numbers, characters, and figures. In this case, in order to apply a predetermined electric field to the liquid crystal layer 30, a large number of matrix-like electrodes may be formed on the inner surfaces of the front substrate 10 and the rear substrate 20, or numbers, characters If it is sufficient to display only a limited number of display contents of the figure, several segment electrodes may be formed on the inner surface of one substrate and a common electrode may be formed on the inner surface of the other substrate. Good. Further, by setting the refractive indexes of the liquid crystal and the polymer, the light scattering state can be set when no electric field is applied, and the light transmission state can be set when the electric field is applied.
[0047]
Since the liquid crystal layer is composed of a liquid crystal molecule and a polymer, this structure does not require the use of a polarizing plate, so there is no loss of light amount due to the polarizing plate unlike TN and STN type liquid crystal devices.
[0048]
In the present embodiment, the reflective electrode 22 is formed by a reflective film deposited on the surface of the resin layer 21 fixed on the inner surface of the substrate 20 on the back side. Here, the resin layer 21 is formed in advance by being provided with a concavo-convex shape 21a and then transferred onto the inner surface of the substrate 20 on the back side. An example of this transfer process will be described below with reference to FIGS.
[0049]
First, as shown in FIG. 2, a photosensitive resin is provided on the surface of the temporary support 1 by a spin coating method, a roll coating method, or the like, and embossed on the photosensitive resin, thereby providing a resin layer having an uneven shape 21a. 21 is formed. In this embossing, the resin surface applied with a molding material such as a mold roller or a mold plate is pressure-molded. For example, at least the resin surface is semi-cured by drying or heating, and then the molding material is allowed to act. Surface irregularities can be formed.
[0050]
Further, the uneven shape 21a of the resin layer 21 is selectively exposed using a photolithography method, through a predetermined photomask or using an interference exposure method, and baked as necessary, and then developed. You may form by doing. In this case, the uneven shape 21a as shown in the figure can be directly created by controlling the exposure amount. However, for example, the dot-shaped resins separated from each other on the surface of the temporary support 1 by the photolithography method described above. It is possible to form a resin layer having a gentle uneven surface state by heating the whole to melt the resin region, and then forming a resin layer having a gentle uneven shape. After making it a moderately smooth shape, you may apply | coat photosensitive resin further on those resin area | regions, and may form the resin layer provided with the uneven | corrugated shape like illustration.
[0051]
The temporary support 1 is preferably a flexible sheet. Examples include silicone paper, polyethylene, polypropylene, polyolefin, and polytetrafluoroethylene sheets. Although the thickness depends on the material, it is 1-125 μm, preferably 10-30 μm.
[0052]
The material of the resin layer 21 is preferably a material softened at a predetermined temperature, for example, 150 ° C. or less, or provided with thermoplasticity having adhesiveness. In the case of using a photosensitive resin, many of the photopolymerizable compositions have this property, but a thermoplastic binder or a compatible plasticizer may be appropriately added. Specific examples include a mixture of a negative diazo resin and an organic binder, a photopolymerizable composition, a mixture of an azide compound and an organic binder, and a cinnamic acid type photosensitive resin composition.
[0053]
The resin layer 21 is formed to a thickness of about 0.2 to 5 μm. The uneven shape 21a is set so as to obtain a desired light scattering characteristic in accordance with the characteristics of the liquid crystal layer 30 to be combined. In general, it is desirable that the uneven shape is as smooth as possible. When the single polarizing plate type liquid crystal layer shown in the present embodiment is employed, the light scattering property on the reflecting surface is required, and therefore the pitch in the planar direction of the concavo-convex shape is 2 to 50 μm and the height of the concavo-convex shape ( The height difference is preferably about 0.1 to 2 μm. When the light scattering type liquid crystal layer shown in the present embodiment is adopted, the pitch of the concavo-convex shape in the planar direction is 30 to 150 μm, and the height (height difference) of the concavo-convex shape is about 0.5 to 2 μm. It is preferable. This is because the pitch in the planar direction needs to be within a range that does not affect the content of the liquid crystal display while preventing the viewer from recognizing the reflected image.
[0054]
On the surface of the resin layer 21, a buffer layer 2 made of a synthetic resin is applied and formed. The buffer layer 2 allows the resin layer 21 to be adhered without any gaps even when the resin layer 21 is transferred onto an uneven surface at the time of transfer. A substance that is allowed and soluble in an alkaline aqueous solution is formed. A thermoplastic resin is preferred when transferring while heating. In particular, a softening point of approximately 80 ° C. or lower is desirable. As such a thermoplastic resin, a saponified product of a copolymer of ethylene and an acrylic ester, a saponified product of a copolymer of styrene and a (meth) acrylic ester, vinyltoluene and a (meth) acrylic ester, And saponified products such as poly (meth) acrylic acid esters and (meth) acrylic acid ester copolymers such as butyl (meth) acrylate and vinyl acetate. Moreover, you may use the raw material which added the plasticizer and reduced the softening point, and as a plasticizer, polypropylene glycol, polyethyleneglycol, dioctyl phthalate, diheptyl phthalate, dibutyl phthalate, tricresyl phosphate, cresyl Examples include diphenyl phosphate and biphenyl diphenyl phosphate. The thickness of the buffer layer 2 is appropriately set depending on the flexibility of the material, but is usually about 1 to 50 μm.
[0055]
An intermediate layer may be formed between the buffer layer 2 and the resin layer 21 in order to improve the adhesion between them. The intermediate layer is preferably one that is dispersed or dissolved in water or an aqueous alkali solution and has low oxygen permeability. For example, polyvinyl ether / maleic anhydride polymer, water-soluble salt of carboxyalkyl cellulose, water-soluble cellulose ether, water-soluble salt of carboxyalkyl starch, polyvinyl alcohol, polyvinyl pyrrolidone, various polyacrylamides, water-soluble polyamide, poly Examples include water-soluble salts of acrylic acid, gelatin, ethylene oxide polymers, styrene / maleic acid copolymers, and maleate resins. The thickness of the intermediate layer may be about 1 to 20 μm.
[0056]
A protective film 3 is stuck on the surface of the buffer layer 2. As the protective film 3, a film having sufficient peelability with respect to the thermoplastic resin of the buffer layer 2, chemically and thermally stable, and flexible is employed. For example, a thin sheet of tetrafluoroethylene, polyethylene terephthalate, polycarbonate, polyethylene, polypropylene or the like. The thickness of the protective film 3 is about 5 to 300 μm, preferably about 20 to 125 μm.
[0057]
Using the laminated film shown in FIG. 2 formed as described above, as shown in FIG. 3, the resin is applied to the liquid crystal layer side surface of the back substrate 20 while peeling the temporary support 1 through the roller 5. The layer 21 is adhered. If the resin layer 21 has sufficient tackiness at room temperature, it is not necessary to heat it, but if it is necessary to increase the tackiness and flexibility of the resin layer 21, it is bonded while heating. Further pressurize if necessary. For example, heating can be performed by incorporating a heater in the roller 4 shown in FIG. 3, and pressure can be applied by the roller 4. The buffer layer 2 is flexibly deformed by heating or pressurization of the roller 4 and pressurizes the resin layer 21 uniformly to enhance the adhesion of the resin layer 21 to the back side substrate 20. In particular, when active elements, wiring layers, and the like are formed in advance on the back-side substrate 20 as in an active matrix type liquid crystal device, irregularities are formed on the inner surface of the back-side substrate 30 by these. Therefore, it is necessary to adhere the resin layer 21 flexibly according to these irregularities, and in such a case, the buffer layer 2 functions effectively.
[0058]
When the laminated film is stuck on the back side substrate 20 as described above, the protective film 3 is peeled off, and the buffer layer 2 is removed with an alkaline aqueous solution or the like, and the intermediate layer is formed. The intermediate layer is also removed. In this way, as shown in FIG. 4, only the resin layer 21 remains on the inner surface of the back-side substrate 20. Then, patterning is performed on the resin layer 21 by an exposure and development process using a photolithography method. This patterning step may be performed as necessary, and if not necessary, the patterning step may not be performed. Further, a resin layer having no photosensitivity may be formed instead of the resin layer 21 and patterning may be omitted.
[0059]
Next, as shown in FIG. 5, Al or the like is deposited on the concavo-convex shape 21 a of the resin layer 21 by a vapor deposition method, a sputtering method, or the like to form the reflective electrode 22. The reflective electrode 22 serves as a reflective layer and a pixel electrode, and is patterned into a shape separated for each pixel region. However, instead of forming the reflective electrode, the reflective layer may be formed entirely and continuously, and a transparent electrode separated for each pixel may be separately formed on the reflective layer.
[0060]
In the present embodiment described above, the resin layer 21 on which the uneven shape 21a is formed in advance is transferred onto the inner surface of the back substrate 20 (on the surface on the liquid crystal layer side), and on the uneven shape 21a of the transferred resin layer 21. Since the reflective electrode 22 which is a reflective layer is formed, it is not necessary to add a complicated process to the back side substrate 20, and the concavo-convex shape is formed from a laminated film formed on a line different from the production line of the liquid crystal device. Since it is only necessary to transfer the resin layer having, the yield and productivity of the manufacturing process are improved.
[0061]
In addition, since the resin layer in which the uneven shape 21a is formed is formed in advance on a line different from the production line, the content of the formation process is not limited by the structure of the liquid crystal device, so the selection range is widened. Unevenness with ideal shape and high shape accuracy due to the fact that the thickness of the underlayer can be easily formed, and means (such as embossing) that are not in the manufacturing process of conventional liquid crystal devices can be used. A shape can be formed. In addition, since the resin layer is made of a photosensitive resin, it is possible to perform patterning according to the structure of the liquid crystal display region, the pixel structure, and the like after transfer.
[0062]
Next, with reference to FIG. 6, the method different from the said embodiment in the formation process of a laminated | multilayer film is demonstrated. In this method, on the surface of the temporary support 1, a filler 24 having a particle size substantially corresponding to the uneven height of the uneven shape is uniformly dispersed in a photosensitive resin, and this resin is temporarily supported. By coating on the surface of the body 1, a resin layer 25 having an uneven shape 25 a as illustrated is formed. Here, the concavo-convex height (height difference) of the concavo-convex shape 25a of the resin layer 25 is determined by the particle size of the filler 24, the viscosity of the resin, other characteristics, the coating method, and the like. The application method may be a spray method, a roll coating method, etc., but the spray method can be easily performed by a method similar to the current method of spraying paint containing dispersoid (a known method using a stirrer or a special spray gun). Can be applied. The pitch in the planar direction of the uneven shape 25a of the resin layer 25 can be adjusted by the dispersion density of the filler.
[0063]
As the filler, fine particles of inorganic substances such as silica and calcium carbonate, and fine spheres of synthetic resin similar to those used as a gap material of a liquid crystal cell can be used. The particle size should be matched to the concavo-convex shape and is about 0.1 to 2 μm. In the above method, the filler is dispersed in the resin in advance, but the resin may be applied by a spraying method after the filler is dispersed on the surface of the temporary support 1. That is, in the present invention, it is only necessary that the fillers are dispersed and arranged, and the uneven shape is created by the presence of the fillers.
[0064]
FIG. 7 shows an inner surface structure of the back-side substrate 20 when the above embodiment is applied to an active matrix type liquid crystal device. In this case, after an active element and a wiring layer are formed in advance on the inner surface of the back side substrate 20, the resin layer 21 is bonded thereon by the method shown in FIG.
[0065]
FIG. 7 shows a case where an MIM (metal-insulator-metal) element, which is a kind of thin film diode element, is formed as an active element. After forming a base layer such as tantalum oxide (not shown) on the inner surface of the back side substrate 20 made of inorganic glass, the wiring layer 26 is formed by sputtering Ta and patterning. In the wiring layer 26, an electrode portion 26a protruding for each pixel region is formed. A thin insulating film 27 made of tantalum oxide is formed on the surface of the wiring layer 26 by an anodic oxidation method, and the connection layer 28 is deposited on the electrode portion 26a with Cr or the like through the insulating film 27.
[0066]
When the resin layer 21 is stuck on the inner surface of the back-side substrate 20 formed as described above by the method shown in FIG. 3, a part of the resin layer 21 is stuck on the wiring layer 26 and the connection layer 28. The Next, the resin layer 21 is selectively exposed and developed to form an opening 21b (contact hole) that exposes the connection layer 28. At this time, patterning may be performed so that the resin layer 21 is simultaneously removed in unnecessary areas of the resin layer 21 such as on the wiring, the sealing area of the panel, and the mounting terminal portion of the panel. Similarly to the above, when the reflective electrode 22 is formed, the reflective electrode 22 and the connection layer 28 are conductively connected through the opening 21b. Here, the electrode part 26a, the insulating film 27, and the connection layer 28 constitute an MIM element. In this embodiment, the MIM element is used, but a thin film transistor can also be used.
[0067]
FIG. 8 shows a configuration in which a thin film transistor is used as an active element. As shown in FIG. 8, a thin film transistor is formed on a substrate, and a resin layer 21 is formed as in FIG. The resin layer is formed on the insulating film, and the connection portion with the drain electrode is opened. An opening that is opened to connect the drain electrode and the pixel electrode is also formed. A pixel electrode 22 is formed on the resin layer. As shown in the drawing, in the manufacturing method according to the present invention, since a resin layer having a concavo-convex shape is formed in advance on the laminated film as the transfer sheet, the resin layer is formed on the back-side substrate constituting the liquid crystal cell. Compared to the case, there are no restrictions on the means for forming the uneven shape. For example, when forming a resin layer on a temporary support or forming a concavo-convex shape, there is no risk of damaging the back side substrate and active elements on the inner surface thereof. Therefore, a resin layer having an optimum thickness and shape can be easily formed because processing such as spin coating, pressurization, and heating can be performed freely. Therefore, the manufacturing method of the liquid crystal device has extremely remarkable and realistic effects.
[0068]
In addition, a laminated film as a transfer sheet can be formed in a large area, and a base insulating layer can be formed on a flat surface, so that the cost merit is extremely large. In addition, since the base insulating layer can be formed on a separate line, mutual contamination with the liquid crystal production line can be prevented, and a great effect can be achieved in that a clean and highly accurate reflector structure can be produced.
[0069]
FIG. 9 is a diagram illustrating an electronic apparatus using the above-described reflective liquid crystal device. For example, FIG. 8A is a perspective view showing a mobile phone. Reference numeral 1000 denotes a mobile phone body, and 1001 of the mobile phone body is a liquid crystal display unit using the reflective liquid crystal device of the present invention (or also referred to as a reflective liquid crystal panel hereinafter).
[0070]
FIG. 9B shows a wristwatch type electronic device. 1100 is a perspective view showing a watch body. Reference numeral 1101 denotes a liquid crystal display unit using the reflective liquid crystal panel of the present invention. Since this liquid crystal panel has high-definition pixels as compared with a conventional clock display unit, it can also display a television image and can realize a watch-type television.
[0071]
FIG. 9C illustrates a portable information processing apparatus such as a word processor or a personal computer. Reference numeral 1200 denotes an information processing apparatus, 1202 denotes an input unit such as a keyboard, 1206 denotes a display unit using the reflective liquid crystal panel of the present invention, and 1204 denotes an information processing apparatus main body. Since each electronic device is an electronic device driven by a battery, the life of the battery can be extended by using a reflective liquid crystal panel having no light source lamp. Further, since the peripheral circuit can be built in the panel substrate as in the present invention, the number of parts is greatly reduced, and the weight and size can be further reduced.
[0072]
【The invention's effect】
As described above, according to the present invention, the resin layer previously formed on the transfer sheet is transferred onto the inner surface of the substrate, and the reflective layer is formed thereon, so that the production line of the liquid crystal device is separated from the production line. Since it is possible to provide a resin layer forming step for defining the surface shape of the reflective layer, it is not necessary to form the resin layer on the substrate, the production efficiency can be improved, and the resin layer can be placed in another location. Thus, the resin layer can be formed more easily and at a lower cost.
[0073]
In particular, by forming a predetermined concavo-convex shape on the surface of the resin layer before transfer to the substrate, a resin layer having a concavo-convex shape is formed in advance on the transfer sheet, and this resin layer is formed on the back side substrate. Therefore, the resin layer can be completed on a separate line from the production line of the liquid crystal device, so that the production efficiency and yield can be improved, and the resin layer is not restricted by the structure of the back side substrate. Therefore, it is possible to form a concavo-convex shape having a desired high shape accuracy more easily and at a low cost.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a schematic structure of a liquid crystal device formed by an embodiment of a method for manufacturing a reflective liquid crystal device according to the present invention.
FIG. 2 is a schematic cross-sectional view showing the structure of a laminated film including a resin layer used in the embodiment.
FIG. 3 is a process explanatory view showing a process of attaching a laminated film to a back side substrate in the embodiment.
FIG. 4 is a process explanatory view showing a back side substrate after a resin layer is attached.
FIG. 5 is a process explanatory view showing a state in which a reflective electrode is formed on a resin layer.
FIG. 6 is a schematic cross-sectional view showing the structure of a laminated film having a resin layer containing a filler.
FIG. 7 is a schematic cross-sectional view showing an inner surface structure of a back side substrate provided with an MIM element.
FIG. 8 is a diagram showing a structure of a thin film transistor and a pixel electrode.
FIG. 9 is a diagram showing an electronic apparatus equipped with the reflective liquid crystal device of the present invention.
[Explanation of symbols]
1 Temporary support
2 Buffer layer
3 Protective film
10 Front side board
11 Transparent electrode
12,23 Alignment film
20 Back side substrate
21, 25 Resin layer
21a, 25a Uneven shape
21b opening
22 Reflective electrode
24 filler
26 Wiring layer
26a Electrode part
27 Insulating film
28 Connection layer

Claims (10)

In a reflective liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates,
Ri Contact is a resin layer is formed having an uneven one of the pair of substrates,
The resin layer is formed by transferring a resin layer having an uneven shape on the surface onto the one substrate,
A reflective liquid crystal device, wherein a reflective layer is formed on the resin layer. In claim 1,
The reflective liquid crystal device, wherein the resin layer is made of a photosensitive resin. In a manufacturing method of a reflective liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates,
The transfer sheet comprising a resin layer having an uneven shape on the surface is transferred onto the substrate one of the liquid crystal device, wherein one of the substrate, and forming a resin layer having irregularities,
Forming a reflective layer on the surface of the resin layer ;
A method for producing a reflective liquid crystal device, comprising: Te claim 3 smell,
Method of manufacturing a liquid crystal device, which comprises forming an uneven shape of the resin layer having an uneven shape on the surface by d Nbosu processing. In claim 3 ,
Method of manufacturing a reflection type liquid crystal device resin layer having an uneven shape on the surface, characterized in that it is made form in a dispersed state microparticles in the resin layer. Te claim 3 smell,
Method of manufacturing a liquid crystal device, which comprises forming an uneven shape of the resin layer having an uneven shape on the surface by off O preparative lithography. Oite method of manufacturing a reflective liquid crystal device according to any one of claims 3 to 6,
The transfer sheet is composed of a resin layer having an uneven shape on the surface, and a protective support laminated on the surface of the resin layer ,
In the step of transferring the transfer sheet onto the one substrate,
After transferring the resin layer onto the one substrate, method of manufacturing the liquid crystal device according to claim Rukoto to be removed by dividing the protective support. Oite method of manufacturing a reflective liquid crystal device according to any one of claims 3 to 7,
The resin layer having an uneven shape on the surface is laminated on a temporary support,
In the step of transferring the transfer sheet onto the one substrate,
A method of manufacturing a reflective liquid crystal device , comprising: removing the temporary support and transferring a resin layer having an uneven shape on the surface onto the one substrate . Oite method of manufacturing a reflective liquid crystal device according to claim 7 or claim 8,
In the transfer sheet, a buffer layer is formed between a resin layer having an uneven shape on the surface and the protective support,
The buffer layer manufacturing method of the reflection-type liquid crystal device comprising a Turkey to exert flexibility at least the transfer sheet when transferred onto the one substrate. Electronic device equipped with the reflection type liquid crystal device according to claim 1 or 2.

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