JP2005321795A - Image display device - Google Patents

Abstract

【Task】
Provided is an image display device in which a scratch on the surface of a light-transmitting member having an image display unit is repaired to such an extent that the presence of the scratch is not recognized even when viewed from all directions at a distance of clear vision.
[Solution]
For this purpose, a liquid filler substantially equal to the refractive index of the light transmissive member is locally filled only in the above-described scratched area and cured. Thereby, the step between the filler surface and the light transmissive member surface is ± 5.0 μm or less, and the angle formed between the surface of the light transmissive member and the filler edge is 45 degrees or less, preferably 10 degrees or less. By controlling the amount of the filler, it is possible to achieve display quality that does not recognize the presence of scratches.
[Selection] Figure 10

Description

  The present invention relates to a non-light-emitting or light-emitting image display device, and more particularly, to provide an image display device that repairs a scratch on the surface of a panel glass in an image display unit, a correction method thereof, and a correction device. It is useful in a device (Thin Film Transistor-Liquid Crystal Display, hereinafter abbreviated as TFT-LCD) and a plasma display panel (hereinafter, abbreviated as PDP).

FIG. 1 shows a schematic diagram of a cross-sectional structure of a well-known TFT-LCD as a representative example of the prior art. In this figure, three flaws 113 formed in error on the surface of the panel glass plate 106 in the display unit are represented.
The scratch 113 is often observed when the manufacturing apparatus contacts the glass surface in the manufacturing process. The place where the scratch 113 is formed is particularly a place where the glass substrate is held on the vacuum suction stage, and the foreign material is often caught between the substrate and the stage.
Although environmental management is carried out at the manufacturing site so as to reduce foreign matter as much as possible, it is impossible to make the foreign matter completely zero, and the glass surface scratch 113 occurs at a statistical frequency. In addition, since it is impossible to check the amount of generated foreign matter for each process, a lighting inspection that is actually performed in the final manufacturing process of the liquid crystal display panel, that is, before the polarizing plate 111 is bonded to the liquid crystal display panel. In many cases, the appearance of the scratch 113 formed on the glass surface is first detected in the overall appearance inspection. And the light from a backlight is scattered in the part of this damage | wound 113, and the display quality as a liquid crystal display device is often impaired to such an extent that it cannot be disregarded.
Since these liquid crystal display panels have already undergone many processes, they have a high added value. Therefore, when the liquid crystal display panel is disposed of in this state, even if the frequency of occurrence is low, the resources associated with the disposal are low. Loss cannot be ignored.
Therefore, it is desired to repair the glass surface scratch 113 by some method from the viewpoint of the social requirement of protecting environmental resources.

In general, the following conventional techniques have been used for the above problems. That is, when a scratch is found on the glass surface in the display portion of the liquid crystal display device, a method of polishing the periphery of the scratch until the scratch disappears has been taken. This method is effective for relatively shallow scratches having a depth of several μm or less, but when repairing deep scratches exceeding 10 μm, the time required for polishing becomes extremely long. It can not be said. In addition, when a flaw having a wider width than that of the flaw described above, for example, a microcrack has developed deeply, there is a problem that repair is no longer difficult.

On the other hand, a method for repairing scratches that cannot be dealt with using a method called polishing is disclosed in Japanese Patent Laid-Open No. 5-150205 or Japanese Patent Laid-Open No. 6-118401.
That is, in the technique disclosed in Japanese Patent Laid-Open No. 5-150205, a liquid organic resin having a refractive index equivalent to or similar to the material of the glass substrate is used for the scratches on the glass substrate of the display panel. This is a method in which the resin is dropped from a dispenser equipped with, and the resin is then thermally cured, and then the excess resin remaining around the scratches is scraped off with a grinder to flatten the glass surface.
However, in this prior art, there is no detailed description about the shape and size of the needle attached to the tip of the dispenser and the supply conditions of the organic resin, and when the repair is completed, the organic resin is not damaged. There is no numerical description of the filling situation. As a result, the criteria for judging how much the wound has been repaired and whether the objective has been achieved is very unclear and it is difficult to judge the effectiveness of this technique.
Further, the technique described in Japanese Patent Application Laid-Open No. 6-118401 is similar to the above-described conventional technique, in which a wound is filled with a liquid organic resin having a refractive index equivalent to or similar to the glass material of the panel, and is thermally cured. Is the method.
However, there is no specific description about the filling method of the organic resin even in this technique. Furthermore, there is no quantitative description of the shape of the repaired portion of the wound, and it must be said that it is difficult to accurately determine its effectiveness.

Japanese Patent Laid-Open No. 5-150205 JP-A-6-118401

As a result of the inventors filling the organic resin into the scratches actually formed on the glass surface of the liquid crystal display panel based on the above-described prior art, there are many problems described below, and the object cannot be easily achieved. It has been found.
First, a method of scraping off excess resin after filling a liquid organic resin into a glass scratch portion on the panel surface and thermosetting will be described with reference to FIG.
When removing excess resin using some method, considering that the smaller the volume of the resin, the easier the treatment is, supply the optimal amount of resin that matches the volume of the flaw as much as possible only in the flaw. It is desirable. The size of the glass scratches 202 varies widely depending on the size of the foreign matter that caused the damage, and various scratches occur from about 50 μm for small scratches and over 500 μm for large scratches. Further, the depth of the scratch 202 has a width of several μm to several tens of μm, and the shape of the scratch is various.
Here, for example, as a typical size of the glass scratch 202, a rectangular parallelepiped groove having a width of 50 μm, a length of 100 μm, and a depth of 5 μm is considered to have a volume of 25000 μm ³ . In order to accurately supply the minimum necessary amount of resin (for the volume of the wound) to the scratch, an injection method that can control the amount of discharge at a very small amount is indispensable. Specifically, a method capable of controlling a single discharge amount to at least 1000 to 5000 μm ³ is required. Therefore, the filling of the resin into the scratch requires repeated high-precision ejection as described above, and a tool capable of ejecting as few droplets as possible is necessary to fill the minimum amount of resin. It is.
Then, it experimented using the micro syringe with the smallest volume (capacity | capacitance 10 microliters) among the micro syringes (small syringe) for gas chromatography which can be obtained as a commercial item. Incidentally, the minimum scale of this microsyringe is 1 μL, and this volume corresponds to a cube of 1 mm on each side (10 ⁹ μm ³ ), which is 4 × 10 ⁴ times the volume of the above-mentioned typical size wound. This is an overwhelming amount. That is, the operation of literally pouring the resin only into the area of the scratch 202 on the glass substrate 201 cannot be performed with a normal syringe or dispenser. When the liquid epoxy resin or the like is actually filled using the above-described microsyringe and then thermally cured, as shown in FIG. 2B, only a considerably excessive amount of resin can be supplied. In this case, the level difference of the surplus resin far exceeded 150 μm. Therefore, in order to perform injection of the filler 203 corresponding to the volume of the scratch 202 and supply only the amount of resin corresponding to the volume of the scratch 202, a method capable of remarkably minimizing the single discharge amount is necessary. It is.

As a second problem, for the time being, if it is assumed that a relatively excessive amount of filler 203 is supplied as described above, a technique for removing excess resin is required.
For example, JP-A-5-150205 discloses that excess resin is removed with an abrasive and a grinder. Therefore, the above-described small microsyringe is used to fill the wound 202 as shown in FIG. 2 (a) with resin, and the surplus filler having the shape shown in FIG. 2 (b) is polished by a grinder. When cut with a cutter, the shape was as shown in FIG. That is, there is a problem that a part of the filler 203 falls off, the surface of the filler 203 becomes rough, or a resin cutting residue 204 is generated around the scratch 202. It was difficult to process a flat shape that left the mark.
This is because the filler 203 itself is excessive, the shearing force when mechanically removing the excess resin is too strong, the filler 203 is likely to fall off, and the amount of excess resin is too large. This is because, for example, the roughness of the processed surface is increased because it is necessary to increase the cutting efficiency by increasing the grain size of the grindstone. Another problem is that a new cleaning process must be added to remove the chips and polishing debris generated by cutting and polishing.
It is desirable not to perform the process of cutting and polishing accompanying the repair of scratches if possible, and it is possible to develop a method for reducing the excess filler as much as possible so that even if the process is performed, simple processing is sufficient. There is a need. That is, in order to facilitate the process of removing the surplus filler, it is desirable that the method supplies the filler 203 in an amount corresponding to the volume of the scratch 202 with high accuracy. Preferably, the filler 203 is supplied only into the scratches 202 by an ultra-high-precision filling method, and is cured by some method that does not damage the entire image display device. Ideally, the glass surface around the scratch 202 is substantially flush and the repair is complete, requiring no machining or the like.

The third problem is a positioning problem in the filling material injection process. Since the size of the wound is about several tens of μm to several hundreds of μm, the wound itself can be recognized with the naked eye. However, in order to accurately inject the filler only into the area of the scratch 202, it is impossible to determine the discharge position of the filler with the naked eye and to achieve the purpose with purely manual operation. In the field of view of the optical microscope, it is necessary to accurately position the tip portion of the filler discharger (for example, a microsyringe as described above) directly above the wound 202.
Unfortunately, there is no description in the above prior art regarding the necessity of positioning operations that are essential to achieve the objectives. As described above, as described above, even if it is assumed that accurate positioning has been performed, the discharge performance of the microsyringe does not solve the problem related to the removal of excess filler.

As a fourth problem, in order to repair the glass scratches 202 at the production site with good reproducibility, an appropriate quantitative evaluation method is necessary for the shape after the scratch repair, and this problem will be described below. To do.
If a precise flaw filling and repair method that can solve the problems described above has been developed, the conditions to be satisfied by the shape of the flaw repair portion will be considered.
First, the fact that the wound was able to be repaired is defined as “the wound has been filled into an appropriate shape with an appropriate filler and finished so that its presence can no longer be recognized by the naked eye”. Here, in the case where there is a scratch on the glass surface of the display panel of the TFT-LCD, which is a representative of the active matrix drive type display device, the cause of the visual recognition that the scratch is a display problem is shown in FIGS. 4 was examined in detail.

The light entering the human eye in the TFT-LCD is divided into two types: light that passes through the opening of the TFT-LCD using the backlight as a light source, and reflected light when external light is reflected by the surface of the display panel. Divided. If the wound repair is incomplete and one of these light paths is blocked, it will be visually recognized and perceived as the presence of a wound.
First, FIG. 3 shows that the glass substrate 301 is filled with a filler 302 having the same or similar refractive index as that of the glass in an amount substantially equal to the volume of the scratch. This is a case where the surface of the material 302 is substantially flush and the surface smoothness (surface roughness) of the filler 302 is repaired so as to be comparable to the surface of the glass substrate 301.
In this case, the light 303 from the backlight travels through a normal optical path without any interruption in the wound repairing part. In addition, the behavior of the external light 304 is not significantly different between the surface of the filler 302 and the surface of the glass substrate 301, and the end of the filler 302 is substantially flush with the glass. It is not the upper singularity. Therefore, it can be said that the wound has been completely repaired and is not visually recognized, and ideal repair of the wound has been realized.

  On the other hand, FIG. 4 shows a case where the filling amount of the filler 402 is slightly larger than the scratch capacity, and a part of the filler 402 is formed to protrude slightly outside the end of the scratch. Since the sizes and shapes of the scratches are various, even if a high-precision filling method is used, it is practically possible that a slight excess filling occurs. Therefore, it is important as a practical problem to provide a standard that clearly defines a shape limit that cannot be visually recognized for the repaired shape as shown in FIG.

Now, as illustrated in FIG. 4, the surface of the filler is substantially flat in most of the flaw repairing portions except the end of the filler 402, and the refractive index between the filler 402 and the glass substrate 401 is substantially the same. Consider the case where they match. In this case, the backlight (1) 405 travels through a normal path without any modulation at the glass / filler interface and the filler / air interface. Therefore, no scratch is recognized in this region. Further, in this region, the external light (1) 406 is similarly free from optical path obstructions and scratches are not recognized.
However, the situation is different at the end of the filler 402. First, when the backlight light (2) 407 enters the end of the filler 402 (the right end in FIG. 4), a part of the light 407 is partially reflected in the lower left direction at the filler / air interface (408). ), The remaining light travels as abnormally transmitted light 409 in a direction deviating from the straight traveling direction. For this reason, the luminance distribution changes in this region, and the end of the filler 402 is visually recognized by the user observing the image display device.
Next, when the external light (2) 410 is incident on the end of the filler 402 (for example, the left end in FIG. 4), the reflected light 411 and the refracted light at the air / filler interface are the same as the previous case. The light branches to 412 and all light travels in a direction shifted from the incident direction. For this reason, since the luminance distribution of light also changes in this region, it is visually recognized by the user. Actually, the modulation received by the backlight light 407 and the external light 410 occurs in the entire outer periphery, which is the end portion of the filler 402, so that the entire filler 402 is visually recognized.

Note that the above-described phenomenon occurs when the filler is slightly insufficient, for example, as shown in FIG. 5 described later, the surface of the filler 1202 is slightly lowered with respect to the surface of the glass substrate 1201. However, the end of the filler 1202 is visually recognized as a result. (Since this principle can be easily understood from the above description, detailed description is omitted.)
By the way, the modulation phenomenon received by the backlight light and the external light depends on the taper angle at the ends of the fillers 402 and 1202 (404 at the left end in FIG. 4 and 1204 at the left end in FIG. 5). That is, as the taper angle is smaller, this modulation phenomenon becomes lighter. As a result, the luminance change at the end portion of the filler becomes small, and visual recognition becomes difficult. In other words, the smaller the taper angle is, the less conspicuous the repaired portion of the flaw is. Therefore, it is very important to determine the optimum value of the taper angle at the end of the filler.

The problems of the prior art described above are summarized and shown below.
The present invention, for example, in an image display device typified by a TFT-LCD, repairs a flaw existing on the glass surface of an image display panel by injecting a filler having the same or similar refractive index as that of glass. Hits the,
(1) Accurate positioning for filling the existing wound area,
(2) Only the wound area is injected with an amount of liquid filler corresponding to the wound volume and cured;
(3) It is desirable to provide means for finishing the surface of the filler and the glass surface around the scratch so as to be substantially in the same plane, and an image display device that realizes the repair of the scratch using this means.
(4) In addition, even if a slight surplus (excess from the scratch) or shortage of the filler occurs in the area of the scratch, the filler is supplied by performing a slight precision polishing as necessary. It is an object of the present invention to provide a means for finishing the taper shape so that the end of the region is not visually recognizable, and an image display device that realizes a wound repair by this means.

  First, in order to correct the above-described scratch on the glass substrate with high accuracy, a technique for supplying a liquid material only to an arbitrary minute region on the glass substrate is required. This problem can be realized by using, for example, the method shown in FIG. 6 using a microinjection apparatus disclosed in JP-A-8-8514. That is, a liquid filler 504 is filled in a pipette 503 formed with an inner diameter of 1 to 10 μm at the tip, and an inert gas is supplied from the other end of the pipette 503 into the pipette in a pulsating manner. An apparatus for performing micro injection of a liquid material is used.

Specifically, the discharge port of the pipette 503 filled with the liquid filler 504 is positioned directly above the wound 502 (FIG. 6A), and the pipette 503 is lowered while keeping the pipette tilt constant, The glass substrate 501 is brought into contact with the scratch 502 (FIG. 6B). Next, the nitrogen gas 505 is supplied in a pulsed manner from the rear to the inside of the pipette 503, and the liquid filler 504 is discharged from the pipette tip (FIG. 6C). The above operation is performed under a microscope, and the pipette 503 is immediately lifted and separated from the glass substrate 501 for each discharge, and the filling state of the scratches 502 is confirmed (FIG. 6D). If the filling amount is insufficient, the discharge of the liquid material is repeated, and the discharge is completed when it is determined that the liquid filler 504 has just filled the scratch 502.
Here, when changing the discharge amount of the liquid filler 504 once, the pressure of the nitrogen gas 505 or the pulse application time may be changed. As a result, the discharge amount of the liquid filler is optimized according to the size of the scratch, and the filler can be injected with high accuracy.

  In order to solve the problems (1), (2) and (3) described above by executing the above-described concept operation, (a) mounting a liquid crystal display panel having a scratch on a stage, A mechanism for positioning; (b) a mechanism for observing the surface of the liquid crystal display panel; (c) a mechanism for positioning by operating a pipette filled with a liquid material; and (d) an inert gas pulsed from the rear of the pipette. It is possible to achieve this by an automatic liquid material supply device having a mechanism for supplying the liquid and discharging the liquid material.

  For example, specifically, after filling a pipette 503 having a tip inner diameter of 1 to 10 μm with an epoxy resin, the pipette is held and the tip is placed at the center of the visual field of the observation optical system. Thereafter, the pipette 503 is lowered, and the contact between the pipette 503 and the substrate 501 is detected from the state where the tip of the pipette is displaced on the surface of the substrate 501. Thereafter, for example, nitrogen gas 505 having a pressure of 150 kPa is supplied from the rear of the pipette 503 in a pulse of 50 msec width. At this time, the tip of the pipette 503 is in contact with the substrate 501 at an angle of 30 to 45 degrees, and the liquid material 504 inside the pipette is discharged from the tip of the pipette 503 with a resolution of a minimum of about 1 pL by supplying pulsed nitrogen. The Then, after the supply of nitrogen is finished, for example, after 100 msec, the pipette 503 is raised to isolate the pipette tip and the substrate 501, whereby the supply amount of the liquid material can be controlled with high accuracy. Incidentally, the relationship between the number of nitrogen pulses supplied from the rear of the pipette and the amount of liquid material supplied is illustrated in FIG. 7, and both are in a substantially proportional relationship.

  Finally, the process proceeds to a curing process for the filler after the liquid filler is injected. As the curing treatment, it is necessary to select optimum conditions depending on the properties of the materials used, but it is possible to employ thermal curing or photocuring on the premise that the liquid crystal display device is not damaged. As the liquid filler, a thermosetting epoxy resin, a thermosetting acrylic resin, a photocuring resin, or the like can be used. As a basic requirement, the refractive index of the liquid filler is the same as that of the glass used in the liquid crystal display device. It is equivalent or comparable, colorless and transparent, and high adhesion to glass.

  In addition, according to the microinjection method described above, the supply of the liquid filler corresponding to the volume of the scratch can be performed with high accuracy for most glass scratches, but the volume of the scratch is relatively small. In some cases, there was a slight overfill. In such a case, it is needless to say that a good filling shape can be obtained by using a tape polishing apparatus, for example, by polishing and removing the surplus swell of the filler.

  The important knowledge obtained by the inventors' experiments is that even if the panel surface and the surface of the filler are not completely coplanar, the height difference between the two is within ± 5.0 μm. If the taper angle formed by the panel surface and the end of the filling material is 45 degrees or less, preferably 10 degrees or less, scratches on the glass surface cannot be visually recognized. This is because when assembling the TFT-LCD, not only the difference in height between the panel surface and the surface of the filler, but also the physical reason that the taper angle between the panel surface and the end of the filler material is small. For example, by attaching a polarizing plate to the repaired glass plate through an adhesive layer having a thickness of about 25 μm, the adhesive layer physically absorbs the above height difference of ± 5.0 μm, and the adhesive layer has a tapered surface. This is because the optical member functions as an optical member that is substantially adapted to eliminate the tapered surface.

  As explained above, the present invention renders the presence of visual scratches indistinguishable by supplying filler locally to the scratches present on the glass surface and When applied to the repair of scratches on the glass surface of a TFT-LCD, the repaired portion can prevent any significant difference in display quality from the peripheral portion.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 8 shows an example of an apparatus for carrying out the first embodiment, and FIG. 9 shows an example of repairing a scratch on the glass surface.

  First, an apparatus for realizing the present embodiment includes an LCD panel 701, a stage 702 for positioning, an objective lens 703 and a CCD camera 704 for observing the surface of the LCD panel 701, and an illumination light source 705. A half mirror 706, a monitor TV 707, a pipette 708 filled with a liquid filler, and a manipulator 709 for holding and positioning the pipette 708 and the surface of the LCD panel 701 at an angle of 45 degrees, for example. For example, an electromagnetic valve 710 for supplying N 2 nitrogen gas in a pulsed manner into the pipette 708, a light source 712 for curing the liquid filler supplied on the LCD panel 701, and the light from the light source 712 to the LCD panel 701 The light guide 711 for irradiating up is comprised.

The pipette 708 used here was formed by stretching a borosilicate hard glass tube having an outer diameter of 1.2 mm and an inner diameter of 0.7 mm by heat treatment, and having a tip inner diameter of approximately 5 μm. The material of the pipette 708 need not be limited to glass.
Further, as the liquid filler filled in the pipette 708, a low-temperature curing type epoxy resin having a viscosity of 160 cps and a cured product refractive index of 1.541 was used. There is no limit.
The primary side of the electromagnetic valve 710 is constantly supplied with 150 kPa of nitrogen gas. Further, the manipulator 709 and the electromagnetic valve 710 are controlled by a controller (not shown).

Here, initialization of nitrogen gas supply conditions for the pipette 708 to be used will be described.
First, the operator uses the manipulator 709 to move the tip of the pipette 708 into the field of view of the monitor TV 707, focuses the tip of the pipette 708, and sets the tip of the pipette 708 to a predetermined reference point on the monitor TV 707. The position of the manipulator 709 at that time is stored in the controller as an initial reference position. Thereafter, the pipette 708 is retracted from the stage 702, the dummy substrate 713 is mounted on the stage 702, and the stage 702 is moved up and down to focus on the surface of the dummy substrate. Here, the dummy substrate 713 is used for a trial experiment for setting injection conditions, and a substrate made of the same material as the LCD panel is used.

Next, in accordance with an instruction from the controller, the tip of the pipette 708 is slowly lowered onto the surface of the dummy substrate 713 and brought into contact therewith. When the tip of the pipette 708 comes into contact with the surface of the dummy substrate, it can be confirmed on the monitor TV 707 that the tip of the pipette 708 is elastically deformed and shifts in the inclination direction of the pipette 708. The optimum amount of deviation of the tip of the pipette 708 when contacting the substrate is usually about 5 to 10 μm.
When contact between the dummy substrate 713 and the tip of the pipette 708 can be confirmed, the liquid filler supply trial experiment is started. Here, the discharge amount per shot at various pulse widths was estimated by fixing the pressure of nitrogen gas at 150 kPa and changing the pulse width of the nitrogen gas supply between 10 msec and 300 msec.
That is, the tip of the pipette 708 is brought into contact with the surface of the dummy substrate 713 to discharge one shot of the liquid filler, and after 0.1 sec, the pipette 708 is retreated upward by 100 μm, and then the stage is moved by 1 mm. This operation was repeated while changing the pulse width of the nitrogen gas supply.
After completion of the series of trial experiments described above, the dummy substrate 713 was placed in, for example, a hot air drying furnace and heated at 100 ° C. for 2 hours to cure the resin as the liquid filler. The shape of the spot-like cured product thus formed was measured using, for example, a laser microscope, the volume of each spot-like cured product was approximated by a triangular pyramid approximation, and the discharge conditions were determined.

As an example, under the conditions of a nitrogen gas pressure of 150 kPa and a pulse width of 30 msec, the amount of epoxy resin discharged per shot was about 5 pL (5000 μm ³ ) in terms of volume after thermosetting.

An example of repairing scratches formed on the glass surface of the TFT-LCD using the above-described conditions will be described with reference to FIG. The glass material of the TFT-LCD of this example is a kind of borosilicate glass, and its refractive index is 1.54.
The glass surface of the TFT-LCD used in the experiment has a scratch of about 3 mm in length and can be easily recognized with the naked eye. As a result of measuring the depth of the scratch with a well-known stylus type surface roughness meter, the maximum depth is 9.4 μm as shown in FIG. A low-temperature curable epoxy resin was injected into the scratch under the above set conditions. Since the wound was elongated, the stage 702 and the pipette 708 were repeatedly moved, and the discharge was sequentially repeated while moving the discharge position in the longitudinal direction of the wound. This operation was performed while checking the degree of filling on the screen of the monitor TV 707. The number of liquid fillers supplied from the pipette 708 was 320 times, but since the short pulse driving was repeated, the total actual work time was about 15 minutes at the most.
After judging that the filling is finished on the screen of the monitor TV 707, the TFT-LCD panel after filling is heated for about 2 hours in a hot-air drying furnace (about 100 ° C.) filled with a nitrogen atmosphere, for example, with a liquid filling material. A resin was cured.
The method for curing the liquid filler is not limited to the hot air drying furnace as long as it can be cured using another heat source.

As shown in FIG. 9B, the surface shape of the wound repaired through the above operations is approximately the same as that before the repair. As shown in FIG. The end shape of the resin is very smooth. That is, even if the surface roughness is measured with respect to the longitudinal direction of the scratch, the surface smoothness after repair is uniform, and the presence of the scratch can be recognized at least under bright field conditions. There wasn't.
The surface shape data shown in FIG. 9 has the aspect ratio of the graph adjusted for notation, so in order to capture the actual shape as an image, it is necessary to enlarge the horizontal axis scale by about 13 times. is there.
As described above, by using a resin having a relatively low viscosity as a filler, the cured resin surface is finished very smoothly, and it is possible to repair the scratch without performing any finishing process again. .

After repairing the scratches on the glass surface using the technique described above, a polarizing plate 911 was bonded using an adhesive 912 through a predetermined process, and a liquid crystal display device was completed. A schematic view of the cross section is shown in FIG. Here, the adhesiveness between the liquid filler 913 (epoxy resin) filled in the scratches and the glass plate 906 is extremely high, and the epoxy resin 913 also adheres well to the adhesive 912 on the back surface of the polarizing plate 911.
When the above-described liquid crystal display device is turned on by a well-known normal method, light from a backlight (not shown) incident from the TFT substrate 902 side passes through the liquid crystal 903 and the color filter substrate 901 to the outside ( It is emitted to the observer side. At this time, a part of the light passes through a scratched portion of the glass surface, but this scratch is filled with a filler 913 (epoxy resin) so that the surface shape is smooth, It behaves as if it is a normal glass surface.
In this way, in the TFT-LCD manufacturing process, even if the glass surface is scratched for some reason, a filler having a refractive index similar to that of glass, such as an epoxy resin, is used only for the scratched portion. It is possible to repair the scratch by filling it, and the liquid crystal display device using the repaired TFT-LCD has display characteristics comparable to a so-called non-defective liquid crystal display device that does not have a scratch. It was confirmed that it can be shipped to the market with the same standard as the non-defective product.

Next, a second embodiment will be described with reference to FIG.
In this example, a photo-curing acrylic resin was used as the liquid filler. This photocurable acrylic resin is a visible light curable resin having a viscosity of 150 cps, a refractive index of a cured product of 1.48, and sufficient photosensitive characteristics up to a visible light region near a wavelength of 450 nm. This resin was filled in the wound using the same method as in Example 1 described above. That is, a pipette 708 shown in FIG. 8 was filled with a photocurable acrylic resin, and the resin was supplied under conditions of a nitrogen gas pressure of 150 kPa and a pulse width of 30 msec. Since this resin is a photo-curing resin, work should be done in a dark room to prevent the resin from curing with the observation light during the work, and light with a short wavelength of 450 nm or less should be cut off from the illumination light source. Used through a filter.
Since the appearance of the scratches present on the glass surface was similar to that in Example 1, the resin was supplied in substantially the same manner as in Example 1, and the number of resin discharges was 390 times. And the short wavelength visible light was irradiated to the area | region of the flaw which complete | finished resin supply through the light guide 711 from the light source 712 for resin hardening shown in FIG. The light source used had an illuminance of 43 mW / cm ^{2 at} a wavelength of 420 nm, and the irradiation time was 30 sec. The amount of irradiation energy at this time is 1300 mJ / cm ² .

The initial scratches on the glass surface and the shape after resin filling / photocuring were measured using a well-known stylus type surface roughness meter, and the results are shown in FIG. The initial depth of the wound was 11.6 μm at the maximum, but the depth after repair measured at almost the same location was about 0.9 μm. The scratches were repaired over the entire area so that they could not be visually recognized at least in the bright field range.
As can be seen from FIG. 11, in this embodiment, the amount of filling into the scratches is slightly insufficient, but a steep step is eliminated in the region where the scratches exist, which is an inadvertent light. It is clear that the occurrence of scattering and refraction is suppressed.
Further, in this example, by using a photocurable resin as a filler for the scratches, the resin can be cured in a very short time, and the repair can be completed. Since simple equipment is sufficient in terms of equipment, it is very convenient in terms of productivity.

As a third embodiment, description will be made with reference to FIG. 12 regarding a case where a slightly surplus-filled flaw is processed and the filler surface is finished in substantially the same plane as the glass surface. In this example, a low-temperature curing type epoxy resin is used as the filler as in the first example, and the resin is supplied using the same discharge conditions, and then in a nitrogen atmosphere in a well-known hot air drying furnace. The scratches made on the glass surface were repaired by heat curing at 100 ° C. for 2 hours. The number of ejections here was 436.
FIG. 12A shows a scratch before filling with resin, and the depth reaches 20 μm. On the other hand, the surface shape after filling the resin is a convex shape of about 3 μm as shown in FIG. The convex shape of about 3 μm of the scratched part compared to the surrounding glass surface can be sufficiently recognized by visual inspection depending on the case where the taper angle is large, and in this state, abnormal refraction or scattering of light occurs. Therefore, it is impossible to exhibit a satisfactory function as a liquid crystal display device.
Therefore, it is necessary to perform a flattening process again on the convex-shaped scratched part, but in this example, the process is performed using a tape polishing apparatus that is generally said to be capable of precise processing. It was. That is, tape polishing was sequentially performed using mesh # 4000 and # 8000 tapes while supplying pure water to a region to be polished (a convex portion after filling with resin). At this time, the change in the shape of the repaired part of the scratch was successively observed with a well-known laser microscope to monitor the progress of polishing and the appearance of the repaired part of the scratch was observed visually (about 25 cm).
The surface of the repaired portion of the scratch was finally polished until it became substantially flush with the glass surface as shown in FIG. Therefore, in this final finished shape, it was impossible to recognize the repaired part of the scratch from the distance of clear vision. That is, it is possible to sufficiently repair the scratch even when a slight surplus is filled by combining the resin filling and the tape polishing to the portion where the scratch exists.
Next, a fourth embodiment will be described with reference to FIG.
The surface of the glass 1601 has a scratch 1602 formed for some reason (FIG. 13A). A liquid filler 1603 was supplied to the scratch 1602 by the method described in the first to third embodiments. In this case, the filler 1603 is supplied so as to completely fill the scratch 1602 (FIG. 13B). When the filler 1603 is in a semi-cured state, the surface of the filler 1603 and the surface of the glass 1601 are substantially the same using the well-known squeegee 1604 or the like. It removes so that it may become a plane (Drawing 13 (c) (d)). Thereafter, the filler 1603 is cured using the method described in the first to third embodiments, and the repair of the scratch 1601 is completed (FIG. 13E).
The end shape of the resin filled by the above-described method is extremely smooth even when the surface roughness is measured, and the presence of a flaw cannot be recognized at least under bright field conditions. . Furthermore, after repairing the scratch, the polarizing plate is pasted through a predetermined process, and the liquid crystal display device is completed, the result of the lighting display is as if the repaired part is a normal glass surface. Demonstrate behavior.

Although the first to fourth embodiments have been described, important findings obtained by the inventors' experiments are that the glass surface and the filler surface as shown in FIG. 4 and FIG. 5, the height difference between the two is within ± 5.0 μm as shown in FIGS. 4 and 5, and the taper formed between the glass surface and the end of the filler is not limited. If the angle is 45 degrees or less, scratches on the glass surface cannot be visually recognized.
FIG. 14 shows an enlarged view of a repaired scratch portion in the assembly of the TFT-LCD illustrated in FIG. In this figure, the filler 1302 filled with scratches has a convex shape. However, a polarizing plate is placed on a glass substrate 1301 including the filler 1302 with an adhesive 1304 having a thickness of about 25 μm, for example. 1303 is attached. At this time, the adhesive material 1304 acts so as to fill the convex portion of the filler 1302, and the adhesive material 1304 is familiar with the filler 1302 at the end of the filler 1302 in the repaired portion, that is, the tapered portion. In effect, the taper surface is eliminated.
As described above, when the thickness of the commonly used adhesive 1304 is about 25 μm, the step (H) between the cured surface of the filler filled in the scratch and the surrounding glass surface is ± 5 μm at the maximum. The adhesive material 1302 will absorb this step if it is below.
Further, the ratio H / W between the level difference (H) and the minimum width (W) of the filler 1302 after curing, in other words, the angle between the surface of the filler 1302 and the surface of the glass 1301 (taper angle). ) Is smaller, the adhesive material 1304 absorbs the effect of the step and optically acts as if there is no step having a taper angle.
FIG. 15 is an explanatory diagram showing a specific example of scratches formed on the glass surface. (A) is an external view of the scratches observed using an optical microscope, (b) is a three-dimensional image of the scratches observed with a laser microscope, and (c) is a cross-sectional profile of the laser microscope superimposed with an image of the optical microscope. It is a representation.
FIG. 16 is an explanatory view showing a specific example of the wound after repair, and each figure corresponds to (a), (b) and (c) of FIG.
From these results, scratches before repair, i.e. large shell-shaped scratches and deep scratches seen in the center of the wounds, are passed through the above-mentioned process of local supply and hardening of the filler, so that visual inspection in the bright field is possible. It is clear that the wound was repaired to some extent because it was difficult to recognize.

Table 1 above is a result of summarizing the relationship between the state of scratches formed on the glass surface and the display quality after the repair of the above-described examples, and the depth of the scratches and the filler after curing Height (H: level difference between the filler surface and glass surface), minimum filler width (W), taper angle at the end of the filler, appearance check after polarizing plate attachment (corresponds to the display characteristics at lighting) )).
As is apparent from this result, when the scratches on the glass surface are filled with a filler and repaired, and a polarizing plate is bonded thereto through a normal process to form an image display device, By controlling the size, shape at the end, etc., it is possible to ensure the same display quality as if there were no scratches.

  As described above, image display devices that were previously discarded as defective products due to scratches on the glass surface have been revived as good products, which contributes to saving resources and production energy socially. Moreover, it can be said that the company has a great effect of contributing to improvement of product yield and cost reduction.

  Further, the above-described embodiments can be applied not only to TFT-LCDs but also to repairing scratches in the display part of other non-light-emitting and light-emitting image display devices. Furthermore, PDPs, electroluminescence elements, flat cathode ray tubes Needless to say, the present invention can also be applied to such display devices.

It is sectional drawing of TFT-LCD which has a damage | wound on the glass surface. It is explanatory drawing at the time of repairing the damage | wound of the glass surface using a prior art. It is a conceptual diagram explaining the repaired damage | wound (when the filler surface and a glass surface are substantially the same planes). It is a conceptual diagram explaining the repaired damage | wound (when the quantity of a filler exceeds the capacity | capacitance of a damage | wound). It is a conceptual diagram for demonstrating the behavior of the light which injected into the repaired damage | wound (when the quantity of a filler is slightly small compared with the volume of a damage | wound). It is the schematic explaining the trace amount filler supply using a microinjection method. It is explanatory drawing showing the relationship between the frequency | count of nitrogen gas supply, and a liquid filler supply amount. It is a block diagram of the microinjection apparatus used by this invention. It is explanatory drawing showing the filler supply state to the glass flaw which is the 1st Example of this invention. It is sectional drawing for demonstrating TFT-LCD which repaired the damage | wound of the glass surface. It is explanatory drawing showing the filler supply state to the glass flaw which is a 2nd Example. It is explanatory drawing showing the filler supply state to the glass flaw which is a 3rd Example. It is explanatory drawing which shows the method of planarizing in the uncured state of resin. It is the schematic for demonstrating a state when a polarizing plate is bonded together on the glass surface containing the damage | wound after a repair. It is explanatory drawing showing a specific example of the damage | wound formed in the glass surface. It is explanatory drawing showing a specific example of the wound after a repair.

Explanation of symbols

101 ... Color filter substrate 102 ... TFT substrate (Thin Film Transistor substrate)
103 ... Liquid crystal 104 ... RGB color material film (Red Green Blue color material film)
105 ... BM film (Black Matrix film)
DESCRIPTION OF SYMBOLS 106 ... Glass plate 107 ... Protective film 108 ... Alignment film 109 ... Pixel electrode 110 ... Common electrode 111 ... Polarizing plate 112 ... Adhesive material 113 ... Glass surface scratch 201 ... Glass substrate 202 ... Scratch 203 ... Filler 204 ... Uncut residue 205 ... Filler drop-off portion 301 ... Glass substrate 302 ... Filler 303 ... Backlight light 304 ... External light 401 ... Glass substrate 402 ... Filler 403 ... Filler step 404 ... Taper angle 405 ... Backlight light (1)
406 ... External light (1)
407 ... Backlight (2)
408 ... Reflected light 409 ... Abnormally transmitted light 410 ... External light (2)
411: reflected light 412: refracted light 501 ... glass substrate 502 ... scratch 503 ... pipette 504 ... liquid filler 505 ... nitrogen gas 701 ... LCD panel 702 ... stage 703 ... objective lens 704 ... CCD camera 705 ... illumination light source 706 ... half mirror 707 ... Monitor TV
708 ... Pipette 709 ... Manipulator 710 ... Solenoid valve 711 ... Light guide 712 ... Light source for resin curing 713 ... Dummy substrate 801 ... Filler 901 ... Color filter substrate 902 ... TFT substrate (Thin Film Transistor substrate)
903 ... Liquid crystal 904 ... RGB color material film (Red Green Blue color material film)
905 ... BM film (Black Matrix film)
906 ... Glass plate 907 ... Protective film 908 ... Alignment film 909 ... Pixel electrode 910 ... Common electrode 911 ... Polarizing plate 912 ... Adhesive material 913 ... Glass surface scratch filler 1001 ... Filler 1101 ... Filler 1201 ... Glass substrate 1202 ... Fill Material 1203 ... Filler step 1204 ... Taper angle 1205 ... Backlight (1)
1206: Outside light (1)
1207 ... Backlight (2)
1208 ... Reflected light 1209 ... Abnormally transmitted light 1210 ... External light (2)
1211 ... Reflected light 1212 ... Refracted light 1301 ... Glass 1302 ... Filler 1303 ... Polarizing plate 1304 ... Adhesive material 1305 ... Taper angle 1306 ... Center line 1601 ... Glass 1602 ... Surface scratch 1603 ... Filler (liquid)
1604 ... Squeegee 1605 ... Filler (cured product)

Claims (6)

A light transmissive member having an image display unit;
Scratches formed on the front and back surfaces of the light transmissive member are locally filled with a filler substantially equal to the refractive index of the light transmissive member,
A step is formed between the surface of the light transmissive member and the surface of the filler, and the step is at least ± 5.0 μm or less. A light transmissive member having an image display unit;
Scratches formed on the front and back surfaces of the light transmissive member are locally filled with a filler substantially equal to the refractive index of the light transmissive member,
A step is formed between the surface of the light transmissive member and the surface of the filler, and the ratio of the step (H) to the minimum width (W) of the filler, H / W is at least 0. An image display device characterized by being 1 or less. A light transmissive member having an image display unit;
Scratches formed on the front and back surfaces of the light transmissive member are locally filled with a filler substantially equal to the refractive index of the light transmissive member,
The filler filled in the scratch of the light transmissive member has a step with the surface of the light transmissive member on which the scratch is formed,
In the region where the end of the filler is in contact with the surface of the light transmissive member, the angle formed by the surface of the filler and the surface of the light transmissive member is at least 45 degrees or less. apparatus.   In the region where the end of the filler filled in the scratch of the light transmissive member is in contact with the surface of the light transmissive member, the angle formed by the surface of the filler and the surface of the light transmissive member is at least 10 An image display device characterized in that it is less than or equal to a degree. A light transmissive member having an image display unit, a light functional film, and an adhesive bonding layer,
The optical functional film is disposed on the light transmissive member via the adhesive bonding layer,
Scratches formed on the surface of the light transmissive member in contact with the adhesive bonding layer are locally filled with a filler substantially equal to the refractive index of the light transmissive member,
The filler filled in the scratch of the light transmissive member has a step with the surface of the light transmissive member in contact with the adhesive bonding layer,
The ratio of the step (H) between the surface of the light transmissive member and the surface of the filler and the minimum width (W) of the filler, H / W being at least 0.1 or less Display device.   The image display device according to claim 5, wherein the optical functional film is a polarizing plate.

Images