JP2013044894A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently form a fine light-shielding film with high accuracy corresponding to a fine pixel defect.SOLUTION: After a resist 45 is applied on an outer surface of a transparent substrate 12 at a position corresponding to a pixel defect 25, the resist 45 is irradiated with laser light to form a hole 46 corresponding to the size of the pixel defect 25, and the hole 46 is filled with a light-shielding material 41 to form a light-shielding film 40. The resist 45 is removed after the light-shielding film 40 is formed; otherwise, if the resist is made of a light-transmitting material, the resist may be left without being removed.

Description

  The present invention relates to a technique for improving the quality by making pixel defects inconspicuous in a liquid crystal display device, and more particularly to a liquid crystal display device suitable for an electronic viewfinder, a near-eye display, and a projector, and a method for manufacturing the same.

  A liquid crystal display device that has become smaller and higher in definition is commonly referred to as a micro display, and has a problem in that pixel defects are likely to occur because pixels and wiring are small. The pixel defect is a state in which normal voltage control cannot be performed on the liquid crystal due to an LSI defect or the like. For example, the pixel defect always becomes a black display or a constant white display state. In particular, when the white display state is always constant, it becomes a bright spot with respect to the black background, and in addition to reducing the quality even in appearance, black cannot be produced and the brightness value is raised, resulting in black floating. End up.

  For these problems, a technology has been devised to form a light-shielding film on the substrate surface at a position corresponding to the pixel defect so as to shield the pixel defect from being seen from the observer side. Accordingly, there is a problem that the light shielding film must be formed finely and with high accuracy in accordance with this, and the light shielding material and the coating apparatus to be used are limited.

  Therefore, as a conventional technique that solves this problem, Patent Document 1 discloses that a light-shielding film is formed by applying a resin in which an organic pigment or dye is dispersed in a photopolymerizable photopolymer to the substrate surface at a position corresponding to a pixel defect. After that, it is described that the outer shape is trimmed into an arbitrary pattern shape by irradiating the light shielding film with a laser.

JP-A-7-181438 (page 8, FIG. 2)

  However, the conventional technique described in Patent Document 1 has the following problems especially when the pixel defect size is small. In the prior art, after forming the light shielding film, the laser is repeatedly irradiated to erase a part of the light shielding film and perform patterning (trimming) of the light shielding film. As the size of the laser beam decreases, the number of laser irradiations increases and becomes inefficient. At the same time, the laser penetrates the light-shielding film and irradiates organic materials such as alignment films and liquid crystal materials, increasing the amount of damage to the normal part. become. That is, the smaller the number of times of laser irradiation, the better.

  The present invention has been made in view of the above problems, and an object thereof is to provide a liquid crystal display device capable of efficiently forming a fine and highly accurate light-shielding film on a substrate surface, and a method for manufacturing the same. To do.

  A liquid crystal display device including a liquid crystal layer having a plurality of pixel regions between a pair of substrates, wherein a light shielding film is formed on an outer surface of the substrate with respect to a position of a pixel region in the plurality of pixel regions where a defect has occurred. And a light-transmitting resist layer is formed in close contact with the periphery of the light-shielding film.

  The resist layer is a liquid crystal display device having the same refractive index as that of the substrate.

  The light shielding material and the resist layer are made of a negative resist material, and the entire surface is exposed to ultraviolet light.

  The light shielding film and the resist layer are a liquid crystal display device having a uniformly polished surface.

  The light shielding film is a liquid crystal display device covered with a protective film.

  A liquid crystal display device comprising a liquid crystal layer having a plurality of pixel regions between a pair of substrates, wherein a light shielding film is formed on an outer surface of the substrate with respect to a position of a pixel region in which a defect occurs in the plurality of pixel regions In the manufacturing method, a resist is formed on an outer surface of the substrate corresponding to a position of a pixel area in which a defect is generated among the plurality of pixel areas so as to cover a wider area than the pixel area in which the defect is generated. A step of forming a layer; a step of removing a portion of the resist layer corresponding to the position of the pixel region in which the defect has occurred; a step of forming a hole; and a step of filling the hole with a light shielding material. A method for manufacturing a display device is provided.

  The hole is a method for manufacturing a liquid crystal display device in which the resist layer is irradiated with a laser.

  According to another aspect of the invention, there is provided a method of manufacturing a liquid crystal display device including a step of removing the resist layer after the step of filling the hole with the light shielding material.

  The light shielding material is made of a positive resist material, the resist layer is made of a negative resist material, and the entire surface of the light shielding material and the resist layer is exposed to ultraviolet rays before the step of removing the resist layer. A method of manufacturing a liquid crystal display device having a process.

  The light-shielding material and the resist layer are made of a negative resist material, and after the step of filling the hole with the light-shielding material, the step of exposing the entire surface of the light-shielding material and the resist layer to ultraviolet light is provided. Let it be a manufacturing method.

  After the step of filling the hole with the light-shielding material, a method of manufacturing a liquid crystal display device comprising a step of uniformly polishing the surface of the light-shielding material and the resist layer.

  The method for manufacturing a liquid crystal display device, wherein the resist layer is made of a light-transmitting material, and in the step of forming the hole in the resist layer, the position of the pixel region in which the defect has occurred is confirmed through the resist layer. And

  According to the present invention, a fine light-shielding film for shielding pixel defects can be formed with high accuracy by a simple process.

It is sectional drawing which shows the liquid crystal display device of Example 1 of this invention. It is sectional drawing which shows the manufacturing method of the liquid crystal display device of Example 1 of this invention. It is sectional drawing which shows the liquid crystal display device of Example 2 of this invention. It is sectional drawing which shows the manufacturing method of the liquid crystal display device of Example 2 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail by taking a reflective liquid crystal display device having an LCOS (Liquid Crystal On Silicon) structure as an example.

  FIG. 1 is a cross-sectional view showing a liquid crystal display device according to Embodiment 1 of the present invention. Hereinafter, a liquid crystal display device according to Example 1 of the present invention will be described with reference to the drawings.

  The liquid crystal display device 1 has a configuration in which a liquid crystal layer 50 is sandwiched between a silicon substrate 11 and a transparent substrate 12. The liquid crystal layer 50 is sealed by a frame-shaped sealing member 60 disposed between the silicon substrate 11 and the transparent substrate 12, and the thickness of the liquid crystal layer 50 is a glass provided arbitrarily in the liquid crystal layer 50. A predetermined size is defined by a spacer (not shown) such as a fiber.

  A plurality of pixel electrodes 21 made of aluminum or the like electrically connected to an LSI (Liquid Crystal Drive Element) are formed on the silicon substrate 11 as reflective electrodes, and each defines one pixel region. An alignment film 31 for aligning the liquid crystal layer 50 is formed on the pixel electrode 21. In order to improve the adhesion between the pixel electrode 21 and the alignment film 31, an adhesion layer may be provided between them.

  A solid transparent electrode 22 is formed on the transparent substrate 12. An alignment film 32 for aligning the liquid crystal layer 50 is formed on the transparent electrode 22. The material of the transparent electrode 12 is a material having high transmittance in the wavelength range of visible light, and indium tin oxide (ITO) or the like is used.

  For the alignment films 31 and 32, for example, an organic film such as a polyimide film is used, and a rubbing process is performed after the thin film is formed.

  The liquid crystal display device 1 displays an image by controlling an electric signal supplied to the pixel electrode 21 and the transparent electrode 22, switching an alignment state of the liquid crystal layer 50, and controlling an amount of light transmitted through the liquid crystal layer 50. The polarized light incident from the transparent substrate 12 side passes through the liquid crystal layer 50, is reflected by the pixel electrode 21, passes through the liquid crystal layer 50 again, and is transmitted or blocked by a polarizing element such as a polarizing plate, and is displayed as an image. The

  Here, among the plurality of pixel electrodes 21, pixel defects 25 exist as electrodes that do not operate normally. The pixel defect 25 is caused by an LSI defect or the like, and it is difficult to completely eliminate it, and the probability of occurrence inevitably increases as the definition and refinement progress. In the pixel defect 25, the electric signal applied to the liquid crystal layer 50 becomes uncontrollable, and the white defect is always displayed as a bright spot, or the black signal is always displayed as a dark spot. In particular, in the case of a bright spot, it becomes conspicuous when displaying a dark image and becomes a factor that causes black floating, and the image quality is greatly deteriorated.

  Therefore, a light shielding film 40 is formed on the surface of the transparent substrate 12 corresponding to the position of the pixel defect 25. The light shielding film 40 is used to shield a bright spot due to the pixel defect 25 and make it a dark spot, and is formed to be the same as or slightly larger than the size of the pixel defect 25. Since the pixel defect 25 can be made inconspicuous by the light shielding film 40, the image quality is improved.

  FIG. 2 is a cross-sectional view illustrating the method of manufacturing the liquid crystal display device according to the first embodiment of the present invention. Hereinafter, the manufacturing method of the liquid crystal display device of Example 1 of this invention is demonstrated using figures.

  First, as shown in FIG. 2A, a resist 45 is dropped on the surface of the transparent substrate 12 using a dropping device 70. The resist 45 is a negative type, and an appropriate amount is dropped at a position corresponding to the pixel defect 25 so as to have a size larger than the pixel defect 25. However, the resist 45 may be uniformly applied to the entire surface of the transparent substrate 12. The dropping device 70 is preferably an ink jet or a dispenser, depending on the size of the pixel defect 25. In addition, when the wettability between the transparent substrate 12 and the resist 45 is poor, it is preferable that the surface of the transparent substrate 12 is modified in advance by performing ultraviolet irradiation or plasma irradiation on the surface of the transparent substrate 12. The applied resist 45 is baked and dried, and is fixed to the surface of the transparent substrate 12.

  Next, as shown in FIG. 2B, a region corresponding to the pixel defect 25 of the resist 45 is irradiated with a laser from the laser irradiator 80, and a part of the resist 45 is removed until the surface of the transparent substrate 12 is exposed. Thus, the hole 46 is formed. At this time, if a light-transmitting material is used for the resist 45 in advance, it is possible to irradiate the laser while accurately confirming the position of the pixel defect 25 through the resist 45. In general, a laser irradiator includes an objective lens and can focus at a high magnification. Therefore, even a pixel size as small as 1 μm square can be handled. However, the means for forming the hole 46 in the resist 45 is not limited to the laser, and other means may be used as long as the resist 45 can be locally removed and can cope with a fine pixel size. For example, the electron beam may be irradiated through a mask having a fine opening corresponding to the pixel size.

  Thereafter, as shown in FIG. 2C, the light shielding material 41 to be the light shielding film 40 is dropped into the hole 46 formed in the resist 45 in FIG. At this time, it is preferable to fill the light shielding material 41 so as not to overflow from the hole 46. However, even if it overflows, if it does not adhere to the surface of the transparent substrate 12, it is removed together with the resist 45 later ( There is no particular problem because it is lifted off. The light shielding material 41 may be, for example, a resin mixed with a pigment or dye such as black ink or carbon black. Further, the dropping device 90 only needs to be able to fill the hole 46 of the resist 45 with the light shielding material 41, and no special specification is required. The dropped light shielding material 41 is fired and dried, and is fixed to the surface of the transparent substrate 12.

  If the resist 45 is uniformly applied to the entire surface of the transparent substrate 12 in FIG. 2A, the purpose of flattening the surface of the applied light shielding material 41 and excess light shielding overflowing from the hole 46 are provided. For the purpose of removing the material 41, it is also effective to uniformly polish the surfaces of the resist 45 and the light shielding material 41 after FIG. As a polishing method, polishing using an abrasive or chemical polishing using a chemical is applicable. When polishing, it is preferable to apply the light shielding material 41 and the resist 45 in a slightly thick state in advance so that the light shielding material 41 and the resist 45 are hardened to some extent.

  Finally, as shown in FIG. 2D, the resist 45 is removed with a resist stripping solution (developer, etc.), so that the light shielding film 40 is accurately formed in the size and position of the pixel defect 25.

  Although the resist 45 has been described here as a negative type, a positive type can also be used, and the present invention does not specifically limit the material of the resist 45. If the resist 45 is a positive type, the resist 45 is baked in FIG. 2A, and then the entire surface of the resist 45 is irradiated with ultraviolet rays. Thereafter, in FIG. Remove.

  Further, when the resist 45 is a positive type, a negative resist such as resin black is used as the light shielding material 41, and after the light shielding material 41 is dropped and baked, the whole surface is exposed with ultraviolet rays including the resist 45, At the same time as reducing the solubility of the light shielding material 41 in the resist stripping solution, the solubility of the resist 45 in the resist stripping solution is increased, and then only the resist 45 is selectively selected using the resist stripping solution in FIG. You may make it remove. In this configuration, since the same resist material is used for the resist 45 and the light shielding material 41, there is an advantage that the configurations of the coating device 70 and the coating device 90 can be partially shared in some cases.

  Note that the resist 45 is not limited to the one generally defined as a resist material, and includes other materials as long as they can be similarly used in the present invention.

  FIG. 3 is a cross-sectional view showing a liquid crystal display device according to Embodiment 2 of the present invention. Hereinafter, a liquid crystal display device according to Example 2 of the present invention will be described with reference to the drawings. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only differences in configuration will be described.

  In the liquid crystal display device 2 of the present embodiment, the light shielding film 40 is formed to be the same size as or slightly larger than the size of the pixel defect 25, and the resist 45 used when forming the light shielding film 40 is transparent around it. It is formed on the substrate 12 as it is. Since the resist 45 having a high light transmittance is used, the display quality is not affected. Further, by using a material having the same refractive index as that of the transparent substrate 12, the interface between the resist 45 and the transparent substrate 12 is used. It is also possible to suppress the reflection of light.

  FIG. 4 is a cross-sectional view illustrating a method of manufacturing a liquid crystal display device according to Embodiment 2 of the present invention. Hereinafter, the manufacturing method of the liquid crystal display device of Example 2 is demonstrated using figures.

  First, as shown in FIG. 4A, a resist 45 is dropped on the surface of the transparent substrate 12 using a dropping device 70. Here, the resist 45 having a high light transmittance is used. The dropped resist 45 is uniformly stretched over the entire surface of the transparent substrate 12 by spin coating or the like. However, the resist 45 may be printed on the entire surface of the transparent substrate 12 by using an ink jet for the dropping device 70. The applied resist 45 is baked and dried, and is fixed to the surface of the transparent substrate 12.

  Next, as shown in FIG. 4B, a region corresponding to the pixel defect 25 of the resist 45 is irradiated with a laser from the laser irradiator 80, and a part of the resist 45 is removed until the surface of the transparent substrate 12 is exposed. Thus, the hole 46 is formed.

  Thereafter, as shown in FIG. 4C, the light shielding material 41 to be the light shielding film 40 is dropped and filled into the hole 46 formed in the resist 45 in FIG. At this time, the light shielding material 41 is preferably filled to the extent that it does not overflow from the hole 46. The light shielding material 41 may be, for example, a resin mixed with a pigment or dye such as black ink or carbon black. The dropped light shielding material 41 is fired and dried, and is fixed to the surface of the transparent substrate 12.

  As a result, as shown in FIG. 4D, the light-shielding film 40 is accurately formed at the size and position of the pixel defect 25, and the resist 45 is formed at other locations. In this embodiment, since the resist 45 does not need to be removed, the process is simplified accordingly.

  Although the resist 45 has been described as a negative type here, a positive type can also be used. Also, considering the reliability of the light-shielding film 40 and the resist 45, it is desirable that the chemical resistance is high. Therefore, both of them use a negative resist, and after FIG. Is also effective. Further, if a material having a high ultraviolet absorption rate is used for the resist 45, the inside of the liquid crystal display device 2 can be protected from the ultraviolet rays.

  Further, for the purpose of flattening the surface of the light shielding film 40 or removing the excess light shielding material 41 overflowing from the hole 46, the surfaces of the light shielding film 40 and the resist 45 are made uniform after FIG. Polishing is also effective.

  In the first and second embodiments, the light shielding film 40 may be covered with a protective film having excellent environmental resistance for the purpose of protecting the light shielding film 40 from the external environment. When the covering region is larger than the outer shape of the light shielding film 40, the material of the protective film is preferably a transparent material so that the portion protruding from the outer shape of the light shielding film 40 does not hinder the transmission of light. In order to suppress deterioration of the light-shielding film 40 due to ultraviolet rays, an ultraviolet absorbing material is more preferable.

  In this specification, the reflective liquid crystal display device having the LCOS structure has been described as an example. However, the present invention is naturally applicable to a transmissive liquid crystal display device in which two substrates are both formed of a transparent substrate. is there.

  The present invention can be widely applied regardless of the alignment method of the liquid crystal, the type of the liquid crystal material, the alignment film and the material of the substrate.

DESCRIPTION OF SYMBOLS 1, 2 Liquid crystal display device 11 Silicon substrate 12 Transparent substrate 21 Pixel electrode 22 Transparent electrode 25 Pixel defect (defective pixel electrode)
31, 32 Alignment film 40 Light-shielding film 41 Light-shielding material 45 Resist 46 Hole 50 Liquid crystal layer 60 Seal member 70 Dropping device (for resist dropping)
80 Laser irradiation machine 90 Dripping device (for dripping light shielding material)

Claims (12)

A liquid crystal display device comprising a liquid crystal layer having a plurality of pixel regions between a pair of substrates,
A light-shielding film is formed on the outer surface of the substrate with respect to the position of the pixel area in which the defect occurs in the plurality of pixel areas, and a light-transmitting resist layer is formed in close contact with the periphery of the light-shielding film. A liquid crystal display device.   The liquid crystal display device according to claim 2, wherein the resist layer has the same refractive index as that of the substrate.   3. The liquid crystal display device according to claim 1, wherein the light shielding material and the resist layer are made of a negative resist material, and the entire surface is exposed to ultraviolet rays.   The liquid crystal display device according to claim 1, wherein surfaces of the light shielding film and the resist layer are uniformly polished.   The liquid crystal display device according to claim 1, wherein the light shielding film is covered with a protective film. A liquid crystal display device comprising a liquid crystal layer having a plurality of pixel regions between a pair of substrates, wherein a light shielding film is formed on an outer surface of the substrate with respect to a position of a pixel region in which a defect occurs in the plurality of pixel regions A manufacturing method of
Forming a resist layer on the outer surface of the substrate corresponding to the position of the pixel region in which the defect occurs among the plurality of pixel regions so as to cover a wider range than the pixel region in which the defect occurs;
Removing a portion corresponding to the position of the pixel region in which the defect occurs in the resist layer to form a hole;
And a step of filling the hole with a light shielding material.   The method for manufacturing a liquid crystal display device according to claim 6, wherein the hole is formed by irradiating the resist layer with a laser.   8. The method of manufacturing a liquid crystal display device according to claim 6, further comprising a step of removing the resist layer after the step of filling the hole with the light shielding material.   The light shielding material is made of a positive resist material, the resist layer is made of a negative resist material, and the entire surface of the light shielding material and the resist layer is exposed to ultraviolet rays before the step of removing the resist layer. The method for manufacturing a liquid crystal display device according to claim 8, further comprising a step.   The light-shielding material and the resist layer are made of a negative resist material, and after the step of filling the hole with the light-shielding material, the entire surface of the light-shielding material and the resist layer is exposed to ultraviolet rays. The manufacturing method of the liquid crystal display device of Claim 6 or 7.   11. The liquid crystal according to claim 6, further comprising a step of uniformly polishing the surface of the light shielding material and the resist layer after the step of filling the hole with the light shielding material. Manufacturing method of display device.   The resist layer is made of a translucent material, and in the step of forming the hole in the resist layer, the position of the pixel region in which the defect has occurred is confirmed through the resist layer. Item 12. A method for producing a liquid crystal display device according to any one of Items 6 to 11.

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