JP4149291B2 - Pixel defect correction method and image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pixel defect correction method for correcting defective pixels for image display in an image display device such as a liquid crystal display or an organic EL display, and an image display device in which defective pixels for image display are corrected.
[0002]
[Prior art]
In general, in an image display device, a large number of pixels are arranged on an image display surface, and each pixel is controlled to perform image display. Therefore, pixels that do not operate normally are defective pixels such as bright spots (pixels are always lit) and black spots (pixels are always off) on image display. For example, in a flat type image display device such as a liquid crystal display or an organic EL display, switching elements (for example, TFT elements) are integrated by fine processing for each pixel. If a mask pattern defect occurs or the switching element itself is defective, the pixel in that portion does not operate normally and becomes a defective pixel. The total number of pixels in the entire image display apparatus is enormous. For example, the total number of pixels in a normal liquid crystal display is approximately several hundred thousand to several million, so it is easy to generate defective pixels.
[0003]
Since these defective pixels cannot be ignored once viewed by the human eye during image display, the image display device in which the defective pixels are generated loses product value. As a result, the product yield decreases. In addition, with the increase in screen size and definition of image display devices, the number of pixels tends to increase or become finer, and the larger the number of pixels, the higher the probability of defective pixels. The yield will be further reduced.
[0004]
In principle, it is possible to prevent the occurrence of defective pixels that cause a decrease in the yield of this product by carefully removing the cause in the manufacturing process, but in order to achieve this, Therefore, expensive capital investment such as improvement of the clean room is required, which increases the product cost.
Therefore, in order to deal with defective pixels that occur in the manufacturing process, it is required to take some measures for the image display device and to correct the defective pixels in the image display inconspicuously.
[0005]
As a method of correcting such a defective pixel, for example, in a liquid crystal display, a method of blocking light transmission of the defective pixel by separating or short-circuiting electrodes related to the defective pixel (see, for example, Patent Document 1), In a liquid crystal display, there is a method of reducing light transmittance by reducing the alignment film function of a portion corresponding to a defective pixel by laser irradiation (for example, see Patent Document 2). All of these methods make use of the fact that black spot defects are less noticeable than bright spot defects, and make the bright spot defects inconspicuous by making the bright spot defects substantially black spots that do not emit light.
For bright spot defects, a method has been proposed in which a light transmission film is provided in advance on the image display surface of an image display device to reduce the light transmittance of a portion corresponding to the defective pixel (for example, Patent Document 3). reference).
[0006]
[Patent Document 1]
JP-A-8-110527 [Patent Document 2]
JP-A-10-62734 [Patent Document 3]
JP-A-9-325332 gazette
[Problems to be solved by the invention]
As described above, since defective pixels reduce the yield of products, it is essential to correct them.
Accordingly, an object of the present invention is to provide a pixel defect correction method for making defective pixels generated in an image display device inconspicuous on an image display, and an image display device in which defective pixels in image display are corrected.
[0008]
[Means for Solving the Problems]
The object is to provide, on the defective pixels on the image display surface, a refractive index changing region having a refractive index different from the surroundings in a plane parallel to the image display surface. That is, the object is to provide the following (1) to (4). This pixel defect correction method is achieved by the image display devices of (5) to (8).
(1) A pixel defect correction method for image display, characterized in that a refractive index changing region having a refractive index different from the surroundings is provided on a defective pixel on the image display surface in a plane parallel to the image display surface.
(2) A pixel defect correction film is provided on the image display surface, and a refractive index changing region having a refractive index different from the surroundings in a plane parallel to the image display surface is provided in a portion located on the defective pixel of the pixel defect correction film. A pixel defect correction method for image display, characterized by comprising:
(3) An image defect correction film having a refractive index changing region having a refractive index different from that of the surroundings in a plane parallel to the film surface is pasted on the image display surface so that the refractive index changing region is located on the defective pixel. An image display pixel defect correction method characterized by the above.
(4) The pixel defect correction method for image display according to any one of (1) to (3), wherein a refractive index change region is provided by changing a refractive index by laser light irradiation.
[0009]
(5) An image display device in which defective pixels of image display are substantially corrected by a refractive index changing region having a refractive index different from that of the surroundings in a plane parallel to the image display surface on the image display surface .
(6) An image display device having a refractive index changing region having a refractive index different from that of the surrounding area in a plane parallel to the image display surface on a defective pixel on the image display surface.
(7) A pixel defect correction film having a refractive index change region having a refractive index different from the surroundings in a plane parallel to the image display surface is provided on the image display surface, and the refractive index change region is located on the defective pixel. An image display device characterized by that.
(8) The image display device as described in (7) above, wherein the pixel defect correction film contains a photochromic material.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
In the present invention, a defective pixel can be made inconspicuous by a refractive index change region having a refractive index different from the surroundings in a plane parallel to the image display surface provided on at least the defective pixel of the image display surface.
This principle will be described with reference to FIG. 1 schematically showing a cross section of the image display side surface portion of the image display device.
[0011]
As shown in FIG. 1, in an image display device, pixels normally composed of RGB (red, green, blue) are arranged, and an image display surface 2 is formed on the surface of a pixel row 4. Usually, a surface portion 5 on which a glass substrate, a protective film, an optical film or the like is further bonded on the image display surface 2 is formed.
In the present invention, the refractive index changing region 1 is provided on the defective pixel 3. The refractive index changing region 1 is a region changed in a plane 6 parallel to the image display surface 2 so as to be different from the refractive index of the surrounding 1 ′, and the refractive index change is caused by the difference in refractive index from the surrounding 1 ′. Light incident on region 1 is scattered. Note that the refractive index of the region other than the parallel surface 6 of the surface portion 5 is generally the same as that of the surrounding 1 ′, and has a refractive index difference from the refractive index changing region 1.
When the refractive index changing region 1 is provided on the defective pixel 3, the defective pixel 3 is not directly seen from the viewpoint O of the observer observing the image display, but the scattered light Ls scattered in the refractive index changing region 1 is As a result, the defective pixel 3 during image display can be made inconspicuous.
[0012]
Even when the defective pixel 3 is a black spot defect that is always extinguished, no light is emitted from the defective pixel 3, but a part of the light L emitted from other pixels enters the refractive index changing region 1. Since the light L is scattered, the defect can be made inconspicuous even when the defective pixel 3 has a black spot defect.
[0013]
The distance between the image display surface 2 and the parallel surface 6 having the refractive index change region 1 in the image display device is not particularly limited. The parallel surface 6 may be provided at any one of the surface portions 5 formed on the image display surface 2.
The viewpoint O of the observer who observes the image display is usually at a distance of several tens of centimeters to several meters from the top of the image display surface 2, whereas the refractive index changing region 1 is a surface in the image display device. In any part 5, it exists at a distance of several tens of μm at most from the image display surface 2. Therefore, since the distance from the image display surface 2 of the refractive index change region 1 is sufficiently smaller than the distance from the image display surface 2 to the observer's viewpoint O, the change is the defect pixel of the present invention. The correction effect is not particularly affected.
[0014]
The parallel surface 6 having the refractive index changing region 1 may be separately provided as a pixel defect correction layer, or may be any other functional layer constituting the surface portion 5 of the image display device. That is, a pixel defect correction film may be provided on the image surface, and the refractive index changing region 1 may be provided on the pixel defect correction film, or a functional film such as another optical film or a protective film or a refractive index of the adhesive film. A change region 1 may be provided.
[0015]
When the refractive index change region 1 is provided in the pixel defect correction film, the pixel defect correction film is provided on the image display surface in advance, and the refractive index change region is located in a portion located on the defective pixel 3 of the pixel defect correction film. 1 may be provided. In addition, after the refractive index change region 1 is first provided in the pixel defect correction film, the pixel defect correction film may be bonded on the image display surface so that the refractive index change region 1 is positioned on the defective pixel 3. it can.
[0016]
An image display device usually has a plurality of defective pixels 3. If the total number of defective pixels appearing during image display is reduced to some extent, the rate at which defective pixels are visible in the entire image display also decreases, so that defective pixels in image display are substantially corrected. Usually, if the refractive index change region 1 is provided on the defective pixel 3 which is preferably 50% or more of the total number of defective pixels, a substantial correction effect on the defective pixel in image display can be obtained. More preferably, the refractive index change regions 1 are provided for the defective pixels 3 of 80% or more, and particularly preferably for all the defective pixels 3, respectively. It is desirable for obtaining a correct correction effect.
In addition to the defective pixel 3, the refractive index change region 1 may also be present on a normal pixel that operates normally. However, in terms of image display image quality, the degree is preferably 20% or less of the total number of normal pixels. 10% or less is more preferable.
[0017]
The refractive index difference between the refractive index changing region 1 and the surrounding 1 ′ on the parallel surface 6 can be arbitrarily set within a range in which light can be scattered and defective pixels can be corrected. In order to obtain the effect of correcting defective pixels, the difference in refractive index may be smaller as the size of the pixel is smaller. For example, the difference in refractive index is 0.03 to 0. Preferably, the difference in refractive index is preferably 0.01 to 0.15 for a pixel having a size of 100 μm to 300 μm square.
[0018]
Further, the refractive index changing region 1 may be formed from a single region having a uniform refractive index, and in order to easily cause scattering, a minute region having a high refractive index and a minute region having a low refractive index are provided. May be formed together.
[0019]
Examples of the method of providing the refractive index changing region 1 on the parallel surface 6 include a method of changing the refractive index of a desired region by applying a physical or chemical action to obtain a refractive index changing region. For example, by locally heating a desired region or irradiating light, an electron beam, or a particle beam, the constituent material is partially decomposed, altered, or crystallized to change the refractive index. Can do. Further, the refractive index may be changed by altering the constituent material using a local chemical reaction.
Among these, light irradiation, particularly a method of irradiating with laser light is preferable because it can easily change the refractive index of a desired region and can change the refractive index of a minute region.
[0020]
In the case of irradiating laser light, for example, a plurality of laser lights having high intensity (0.1 to 100 kW) and narrow pulse width (100 to 1000 fs) are used, and the light is focused and irradiated. The constituent material can be altered by a multiphoton reaction to change the refractive index. It is convenient and preferable to use a two-photon reaction using two laser beams.
Further, in the present invention, DA Parthenopoulos et al., “Three-dimensional optical storage memory”, Science Vol.245 (1989) p.843, DA Akimov et al., Jpn. Appl. Phys., Vol. 36 (1997) p.426 can also be used.
In the case of the method using a plurality of laser beams, it is possible to change the refractive index only to a minute region in which the plurality of laser beams are focused. It is possible to form a refractive index changing region in which minute domains are distributed.
[0021]
Further, in order to form the refractive index changing region 1, a material whose refractive index changes by the above-described various methods may be used as the parallel surface 6. Such a material is not particularly limited, but a photochromic material is a preferable material because it can be easily altered by light irradiation and the refractive index can be changed by this alteration.
Examples of the photochromic material include spiropyran, fulgide, and diarylethene.
[0022]
As described above, in the present invention, a pixel defect correction film can be used to provide the refractive index change region 1.
The pixel defect correction film includes a pixel defect correction layer (pixel defect correction layer) as the parallel surface 6 having the refractive index change region 1, and may include a support and other layers as necessary. It is preferable to form a pixel defect correction layer on the support.
[0023]
The material constituting the pixel defect correction layer may be organic or inorganic as long as it can form the refractive index change region 1 in this layer. In particular, the photochromic material is preferable.
The pixel defect correction layer can be formed on the support by a known vapor deposition method or coating method.
[0024]
Examples of the main component of the support for the pixel defect correction film include polystyrene, polycarbonate, polysulfone, and polyethersulfone.
[0025]
Examples of the image display device used in the present invention include a liquid crystal display, an organic EL display, a plasma display, and a CRT display. In any image display device, the defective pixel in the image display can be corrected by providing the refractive index change region on the defective pixel.
[0026]
【Example】
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
[0027]
(Preparation of pixel defect correction film)
A methylene chloride solution of polyethersulfone (15% by mass) was cast on a steel drum, and continuously peeled off while suppressing stretching, to obtain a support film having a thickness of 50 μm. A 1% by mass solution of diarylethene (photochromic material) was applied onto this support film and dried to provide a pixel defect correction layer having a thickness of 10 μm, thereby producing a pixel defect correction film.
[0028]
(Correction of defective pixels in display images on liquid crystal displays)
Among the commercially available liquid crystal display devices, those having black spots caused by defective pixels (pixel size 300 μm × 300 μm) were prepared.
Irradiating light of a titanium / sapphire laser with a wavelength of 760 nm (50 kW, pulse width: 130 fs) onto the pixel defect correction layer of the pixel defect correction film prepared as described above, and photodiisotropically diarylethene molecules by a two-photon reaction. Thus, the refractive index of the laser irradiation region was changed to provide a refractive index change region. The size of the refractive index change region is about 100 μm × 100 μm, and the refractive index difference from the periphery of the pixel defect correction layer is about 0.05.
Next, a pixel defect correction film was bonded to the surface of the liquid crystal display so that the refractive index change region covered the black spot.
[0029]
This liquid crystal display was displayed in red, and the state of the defective pixel before and after the pixel defect correction film was bonded was visually evaluated. As a result, it was found that when the pixel defect correction film is pasted, the black spot becomes slightly brighter and the defective pixel becomes difficult to see compared to the case where the film is not pasted.
[0030]
【The invention's effect】
As described above, according to the present invention, by providing the refractive index change region on the defective pixel, the defective pixel of the image display can be corrected to be inconspicuous, and the manufacturing yield of the image display device can be improved. Can do.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a display-side surface portion of an image display device schematically showing that a defective pixel is corrected by a refractive index change region.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Refractive index change area | region 1 'Area | region around the refractive index change area | region in the surface parallel to an image display surface 2 Image display surface 3 Defective pixel 4 Pixel row | line | column 5 Parallel surface L which has a refractive index change area | region From a normal pixel Light Ls Scattered light from the refractive index change region

Claims (3)

A pixel defect correction film is provided on the image display surface, and a refractive index changing region having a refractive index different from the surroundings in a plane parallel to the image display surface is provided in a portion located on the defective pixel of the pixel defect correction film , 2. A pixel defect correcting method for image display, wherein the refractive index changing region is made optically anisotropic with diarylethene molecules by irradiating laser light . An image defect correction film having a refractive index changing region in which a diarylethene molecule is photo-anisotropically changed by changing the refractive index by irradiating a laser beam in a plane parallel to the film surface. A pixel defect correction method for image display, comprising: pasting on an image display surface so as to be positioned on a pixel. A pixel defect correction film having a refractive index change region having a refractive index different from that of the surroundings in a plane parallel to the image display surface is provided on the image display surface. The refractive index change region irradiates a laser beam to emit diarylethene. An image display device comprising molecules made photo-anisotropic, wherein the refractive index change region is located on a defective pixel.

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