JP2004132976A - Manufacturing method of optical device and testing device for defective determination for this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a testing device for determination of a display defect including display irregularity and the like to be appeared on a display surface of a plane display device and a manufacturing method of the plane display device using this which are capable of making determination of display irregularity and the like precisely and reliably without being affected by skill level and some difference of operation conditions. <P>SOLUTION: Variable density display patterns 21, 22 consisting of black dots of 30μm are printed on a transparent rectangular sheet 15. These variable density display patterns 21, 22 are respectively provided so that dot area occupation ratio becomes equal to each setting value from 3 to 45 percent and are used as a standard of density to compare with a display irregularity of a determined object or a candidate. A level of density of display irregularity and the like is determined whether it is visible or not in the case that the display irregularity of determination object is overlaid to cover the display irregularity of the determination object. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a method for manufacturing an optical device such as a flat panel display. Further, the present invention relates to an inspection tool used for this.

2. Description of the Related Art In recent years, flat display devices such as liquid crystal display devices have been used in various fields as display devices such as personal computers, word processors or TVs, and as projection display devices, taking advantage of the features of thinness, light weight, and low power consumption. ing.

Among them, active matrix display devices in which a switch element is electrically connected to each pixel electrode are capable of realizing good display images without crosstalk between adjacent pixels, and are being actively researched and developed. .

In the manufacture of flat panel display devices, when the display panel body or the flat panel display module is completed, wiring or conductive patterns are disconnected or short-circuited, and unevenness in brightness or chromaticity due to dust or partial defects is displayed. An inspection is performed to detect a defect. In general, an inspection for detecting a defect such as a disconnection or luminance unevenness is performed by inputting a predetermined inspection signal from the signal line pad and the scanning line pad and observing a display state of a pixel. Such an inspection is called "lighting inspection" because the light source device is turned on.

Various proposals have been made to use an automatic device equipped with a CCD camera and an image processing mechanism for lighting inspection of a display panel (for example, Japanese Patent Application Laid-Open Nos. 8-145848 and 11-101712). However, in the lighting inspection, it is easy to detect and determine a disconnection, a short circuit, a clear black spot (dark spot), and the like. It was relatively difficult to determine whether the value was within the allowable range. For this reason, under the present circumstances, the efficiency and accuracy of detecting and judging subtle display unevenness often fall short of a visual inspection by a skilled inspector.

By evaluating the degree (density) and the number of luminance unevenness appearing on the display surface, it is possible to determine whether the panel can be shipped from a non-defective panel or from a defective panel, but generally requires a high level of skill. In short, an inspector with a low level of skill would generate a considerable judgment error.

目 Visual inspection for luminance unevenness for defect determination is generally performed by one of the following methods.

(1) As a reference for comparison, a display panel in which unevenness of a specific darkness has occurred and which slightly exceeds the allowable limit (a sample of defective products) or is barely within the allowable limit Use a good sample (limit sample of good products). That is, the non-defective / defective product is determined by comparing these limit samples with the display panel to be inspected.

(2) An ND filter (Neutral Density filter) having a specific transmittance is superimposed on a portion of the display unevenness on the display surface to determine whether or not the display unevenness is visible. If it cannot be seen, it is judged to be within the allowable limit, and it is judged to be good. If it can be seen, it is judged to be defective.

(3) A signal input from the lighting inspection device to the display panel is devised so that display unevenness of a specific density is displayed on the display surface. That is, the same pattern as the display unevenness is expressed on the display surface using specific software. By comparing with this, it is determined whether or not the display unevenness of the display panel is within the allowable limit.
JP-A-8-145848 JP-A-11-101712

従 来 Each of the conventional display unevenness determination methods as described above has the following problems.

(1) Method of using the actual display panel as a limit sample It is necessary to use a display panel having unevenness of a specific density, but the existence probability of such a suitable one is low.

(4) In order to perform an efficient inspection, it is necessary to arrange two devices for driving the display panel side by side. If there is only one drive device, it is necessary to set a display panel as a limit sample, light it up, set the display panel to be determined, and compare it with memory. Become. Therefore, considerable skill is required, and the possibility of a judgment error increases.

Furthermore, the display unevenness appearing on the display panel for the limit sample often decreases with time. Therefore, a check management task of checking the density of display unevenness occurs at regular intervals.

(2) Judgment using ND filter Judgment using the ND filter is strongly affected by the environmental lighting at the work place, so it is necessary to strictly control the illuminance.

Ｎ In addition, commercially available ND filters have large variations in transmittance. For this reason, even if the illuminance management is strictly performed, there is a variation in the determination due to the variation in the transmittance.

(3) Method of displaying a pattern similar to display unevenness by software In a normal display panel such as a liquid crystal panel, the shading changes sharply depending on the angle of the line of sight (viewing angle) with respect to the display surface.

The present invention has been made in view of the above problems, and provides an optical device manufacturing method and an inspection tool that can improve the accuracy of determining the defect of optical unevenness appearing on the main surface of an optical device. .

The inspection tool of the present invention is an inspection tool used for determining the density of display unevenness appearing on the display surface of a flat panel display device, and is formed on a transparent sheet or film by shading of dots having a size of 40 μm or less. A display pattern is provided.

With the above configuration, the judgment can be made with high accuracy and reliability without being influenced by the skill level or slight differences in working conditions.

Preferably, a plurality of the gray scale display patterns are arranged in parallel on one sheet or film, and these have different occupancy rates of dot portions per area.

と With such a configuration, the determination of the density can be performed quickly.

In addition, more preferably, for measuring the diameter or width of the display unevenness, a plurality of width slit pattern or line, or a plurality of diameter punching pattern or solid pattern, on the transparent sheet or film, together. Provided.

With such a configuration, the diameter or width of the display unevenness can be easily evaluated almost simultaneously with the determination of the density.

The method for manufacturing a flat panel display device according to the present invention includes, before or after mounting a driving circuit system on a peripheral portion of the display panel, performing a lighting inspection for inspecting a display defect by operating the display panel. In the method of manufacturing a flat display device, the unevenness is detected and a determination operation is performed to determine whether the detected display unevenness is within an allowable range in terms of density or dimensions. In advance, a pattern provided with a gray scale display pattern composed of dots having a size of 40 μm or less is prepared in advance, and the gray scale display pattern is compared with the display unevenness to determine whether the gray scale levels are equal or in a magnitude relation. To determine the density of the display unevenness, or determine whether the display unevenness is visible when covered with the grayscale display pattern. And judging the density of the display unevenness by.

(4) The accuracy of defect determination of optical unevenness can be remarkably improved.

検 査 The test tool used in the present invention is a light-transmissive, colorless and transparent sheet or film provided with a density pattern composed of, for example, an aggregate of dots having a size of 40 μm or less.

As a base sheet or film (hereinafter, also referred to as a sheet including a sheet having a small thickness), any sheet having appropriate transparency (light transmittance and haze) and durability can be used. . Preferable examples include a sheet having a thickness of 50 to 500 μm made of an olefin resin such as polymethylpentene resin, a saturated polyester resin such as PET (polyethylene terephthalate) or polyethylene naphthalate, a methacrylic resin or an acrylic resin. And it is desirable that it be colorless and transparent. If a colorless and transparent sheet is used as the base of the density pattern, it is possible to inspect not the absolute density but the degree of optical unevenness of the inspected object with respect to the underlying color.

(4) A plurality of density patterns are provided on the transparent sheet as a base by a general printing method such as photolithography. The base transparent sheet is subjected in advance to a process for improving printability as needed. In some cases, the density pattern can be provided by an inkjet drawing method or an offset method.

Each density pattern is preferably one in which dots (halftone dots) of discontinuous circular or rectangular shapes are uniformly distributed, and the occupancy of the dot portion with respect to the area of the pattern arrangement location is different, so that each level of each density pattern is different. Expresses light and shade. This dot may be a checkered pattern or the like.

The dots forming the density pattern are preferably black and have a size of 40 μm or less, preferably 20 to 35 μm. If the size exceeds 40 μm, interference fringes such as a moire pattern may appear and adversely affect the display. On the other hand, a size smaller than 20 μm is not preferable because the cost for forming a density pattern by printing or the like increases. Further, there is no merit in performance even if the size is reduced in this way.

The present invention may have at least one density pattern. Preferably, a plurality of density patterns having different density levels are formed. If the allowable value of the optical unevenness does not always fluctuate, it is sufficient to provide at least one density pattern of a density level corresponding to the optical density unevenness. It is desirable to have. Also, density patterns of a plurality of density levels may be formed at predetermined density intervals, and can be used as a scale for grasping the degree of optical unevenness. When a plurality of density patterns are formed, it is desirable that the order of arrangement of the density patterns be arranged in accordance with the order of the density levels. This makes it possible to determine which level range is included. Here, density patterns with density intervals of 1% to 2% are arranged for density levels near the allowable value, and density intervals up to 45% are set in 5% increments.

By forming the inspection tool in this way, the inspection can be performed more easily as compared with the case where the inspection is performed using a plurality of inspection tools having different density levels. Further, it is possible to manage not only the presence / absence of the optical unevenness defect but also the degree thereof.

検 査 The inspection tool of the present invention is preferably provided with a pattern for measuring or determining the size of optical unevenness, here, display unevenness. Specifically, it is provided by a pattern forming a slit of a fixed width or a line segment of a fixed width, or a rectangular or circular cut pattern of a predetermined diameter in a solid pattern, or a rectangular or circular pattern of a predetermined diameter. A pattern for dimension determination is provided by the solid pattern of the shape.

The determination of optical unevenness using the inspection tool of the present invention can be performed by detecting optical unevenness or a candidate for the optical unevenness, comparing the optical unevenness with a predetermined density pattern, and checking whether or not the density is equivalent. it can.

For example, as shown in FIG. 3, when an allowable density is set for each dimension of display unevenness, the density is equal to or lower than the density pattern of the predetermined level, or It is determined whether or not the density is higher, and thereby, display non-uniformity that causes a problem is specified. If the number of such display unevenness per display panel exceeds the allowable limit, it can be determined that the display is defective. Alternatively, whether the display panel is defective is determined by whether or not the value obtained by multiplying the number of display irregularities having a density equal to or higher than a certain level by a coefficient determined by the dimension and the density level exceeds a set allowable value. You can also decide.

In this case, as shown in FIG. 4, an inspection tool is placed on the main surface of the optical device, which is a light emitting surface, and a sheet-like sheet is placed so that an appropriate density pattern is adjacent to the display unevenness. By arranging the inspection tool, the judgment can be made easily. In particular, as a density gauge, by arranging a plurality of density patterns having different levels of density stepwise, for example, in a line in the order of the levels, a series of density patterns are sequentially placed next to the display unevenness to be determined and compared. And the determination operation can be easily performed. Moreover, it can be performed very quickly.

Instead of the above-described comparison and comparison, the density pattern is superimposed on the display unevenness to be determined, and the display unevenness is determined based on whether or not the display unevenness is visible. You can also. Also in this case, the judgment operation can be performed easily and quickly by sequentially superimposing the image data on the rows of the density patterns having different density levels in a stepwise manner.

判定 The judgment by the comparison control or the coating can be made by the operator observing with the naked eye, a loupe or a stereoscopic microscope. In some cases, it is possible to determine the visibility and the like in the covered state by an automatic device using image analysis.

表示 Such display unevenness inspection can be performed by lighting inspection after assembling the display panel main body and before or after assembling a TCP (tape carrier package) or a driving PCB (that is, after completion of the display panel). In some cases, it can be performed after a backlight device or the like is assembled.

Note that the manufacture of an array substrate or a counter substrate in a flat display device is performed, for example, by the method described in JP-A-9-160076 or JP-A-2000-267595, or JP-A-2000-330484 or JP-A-2001-339070. be able to.

The inspection tool and the inspection method of the present invention can be used not only for a liquid crystal display device but also for an organic EL display device and the like. In addition, the determination of the gray level or the density can be performed not only for the luminance level in the case of white display but also for the gray level in the case of performing a specific color display. In this case, the dots of the density pattern may be provided as a pattern of the specific color.

In the case where a black dot is used as in the present embodiment, it is desirable to perform the inspection in a halftone gray display state.

As the display unevenness of the detection and judgment contrast, it is supposed that the display unevenness is primarily caused by a foreign substance. However, the shape is not limited to a linear shape.

Next, specific examples of the present invention will be described with reference to FIGS.

First, an inspection tool according to an embodiment will be described with reference to FIGS.

As shown in FIG. 1, the inspection tool 1 is provided with a shade gauge 2 for determining the density of the display unevenness on the right half part of the rectangular transparent sheet 15, and the display half of the display unevenness is provided on the left half part. A dimension gauge 3 for measuring the approximate dimensions is provided.

The shade gauge 2 is a vertically arranged screen tone print pattern (density patterns 21 and 22) for displaying the density (luminance level) of each level. Specifically, a pattern of each level of density, which is a pair of a square density pattern 21 having a square of 5 mm and a circular density pattern 22 having a diameter of 0.5 mm on the right side, is arranged in the vertical direction. It is a thing. The pairs of the density patterns 21 and 22 are arranged in nine steps with the dot area occupancy of 3 to 45%, and are arranged in ascending order toward the near side.

FIG. 2 schematically shows a dot configuration of a pair of density patterns 21 and 22 having a dot area occupancy of 3% and a pair of density patterns 21 and 22 having a dot area occupancy of 45%. Show. As shown in FIG. 2, each dot forming the density patterns 21 and 22 has an independent circular shape in the embodiment. Note that the diameter of each dot is all 30 μm.

文字 To the left of the density pattern 21, a character print 23 for displaying the numerical value of the dot area occupancy is applied.

As described above, in the density pattern of each density level, the pattern outline has a square pattern and a circular pattern, so that it is possible to inspect using a density pattern of an appropriate size and pattern depending on the shape and degree of unevenness. The inspection accuracy can be improved.

On the other hand, the dimension gauge 3 provided on the left side of the transparent sheet 15 is an array of patterns representing the dimensions at each stage in order to quickly evaluate and measure the dimensions of the display unevenness. Specifically, a set of dimension display patterns 31 to 34 is provided for each dimension set in 16 steps in the range of 0.03 to 0.70 mm, and these are arranged in the vertical direction.

A set of dimension display patterns for each dimension value includes a rectangular dot pattern 31 and a linear pattern 32 located on the right side thereof. Further, it includes a cut dot pattern 33 and a cut straight line pattern (slit pattern) which are arranged on the front side of these patterns 31 and 32 and are obtained by inverting the black and white of these patterns 31 and 32. Note that a character print 35 for displaying dimensions is provided on the left side of each set of dimension display patterns 31 to 34.

When measuring the size of the display unevenness using the dimension gauge 3, the inspection tool 1 is arranged so that the rectangular dots 31 or the linear patterns 32 are immediately adjacent to the display unevenness to be measured. By successively performing such operations, when an equivalent-sized one is found, the size shown in the character print 35 on the left is recorded as the size of the display unevenness. The measurement of the size of the display unevenness can be similarly performed by an operation such as arranging the inspection tool 1 such that the display unevenness “fills” into the blank pattern 33 or the slit pattern 34.

Tables 1 and 2 show the evaluation results on the effects and the like of the method using the test tool of the example.

Table 1 shows the average value of the rate of correct answer when 10 display panel samples were judged as good or defective within a predetermined short time by five inspectors having different skill levels. Similarly, the non-defective product erroneous determination rate (overkill) in which a non-defective product is erroneously determined as a defective product and the defective product erroneous determination rate (underkill) in which a defective product is erroneously determined as a non-defective product are also shown. In addition, under the same conditions, a test was performed on the results using the “limit sample” according to the related art, and the results are collectively shown in Table 1 as comparative examples.
As can be seen from the results in Table 1, the overkill significantly decreased from 20% to 2% as compared with the conventional technique using the "limit sample", and as a result, the accuracy rate of judgment was greatly improved.

Although not shown in Table 1, in the case of the method according to the embodiment, the accuracy rate of judgment by an unskilled inspector is remarkably increased as compared with the comparative example using “limit sample”, and the judgment result by the expert inspector is obtained. The difference from that has been significantly reduced. Furthermore, differences in judgment results due to individual differences among inspectors, not limited to skilled and unskilled, are also reduced.

Next, Table 2 shows the results of using the test tool 1 of the example to determine the actual two display unevennesses appearing on the display panel at each environmental illuminance. Here, the determination is made based on the density pattern 21 of 5 mm square, and the numerical value of the dot area occupancy of the shade display pattern 21 that looks equivalent in density is shown. Further, as in the case of Table 1, the average value of the evaluation results by five inspectors was shown.
In any of the display unevenness samples, the influence of the environmental illuminance was not observed at all in the determination of the density. That is, according to the method of the embodiment, the inspection can be reliably performed without being affected by the environmental illuminance at the inspection location, and labor for keeping the environmental illuminance constant can be saved.

The density gauge 2 can be easily and stably manufactured by dot printing. Further, since there is no change in the density level as long as it does not flake off, it is not necessary to manage such a change in the density level. Further, since the printing pattern is used, there is no variation due to the viewing angle. In other words, the creation and preparation of the density reference standard, and the storage and management thereof become much easier, and the cost is reduced.

In addition, since the judgment is performed in a state where the inspection tool 1 is arranged on the display panel or in the vicinity of the display panel, the inspector does not need to memorize the density of the display unevenness, and skill is required for the judgment. And not. Further, there is no need to actually prepare a display panel (limit sample) in which display unevenness of a specific level appears. Further, it is possible to make a determination at a plurality of bases based on the same reference. When used on a display panel, it is affected by the backlight light and the environmental illuminance equivalent to the portion of the display unevenness. Therefore, under normal conditions, the evaluation of the shading is not affected by the illumination conditions. . That is, the inspection can be performed simultaneously under the same condition, the reliability of the density determination can be greatly improved, and the variation in the evaluation can be significantly reduced.

濃度 In the density pattern, the desired density level can be easily achieved by freely setting the area occupancy of the dots. Therefore, it is possible to quickly and flexibly cope with the change of the display panel type. In addition, since the density level can be easily quantified based on the area occupancy of the dots, data can be obtained by objective evaluation.

Furthermore, the time required for determination can be greatly reduced, and the work efficiency of inspection can be greatly improved.

The embodiment of the present invention has been described using a display device as an example. However, the present invention is not limited to this, and can be applied to all optical devices that perform planar light output. For example, the present invention can be applied to determination of quality and degree of optical unevenness in a light emission surface of a lighting device such as a planar light source.

It is an outline view showing the whole inspection tool of an example typically. It is a typical partial enlarged view for explaining the pattern (shading display pattern) of each screen tone which forms the shading gauge of the inspection tool of an example. FIG. 2A shows a screen tone with a dot occupancy of 3%, and FIG. 2B shows a screen tone with a dot occupancy of 45%. It is a typical flowchart for explaining the procedure of the quality judgment using the inspection tool of the present invention. FIG. 3 is a schematic plan view showing a state in which the inspection tool of the present invention is superimposed on a light emission surface of an optical device and arranged so that a density pattern is adjacent to display unevenness.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Inspection tool for display unevenness determination 15 Transparent film 2 Print pattern forming gray scale 21 Shade gray display pattern of 5 mm square 22 Round circular gray display pattern of 0.5 mm diameter 3 Print pattern forming dimension gauge

Claims (16)

In the method for manufacturing an optical device, which detects in-plane optical unevenness on one main surface of the optical device and performs a determination operation for determining the degree of the density of the detected optical unevenness,
On a transparent sheet or film, an inspection tool provided with at least one density pattern is placed on the main surface of the optical device,
An optical device, comprising: comparing and contrasting the density pattern and the optical unevenness to determine whether the density levels are equal or the magnitude level of the display unevenness by determining whether there is a magnitude relationship. Production method. 4. The method according to claim 1, wherein the optical device is in an operating state and emits light from the main surface. 2. The method of manufacturing an optical device according to claim 1, wherein the inspection tool is mounted on the main surface of the optical device so that the density pattern is adjacent to the optical unevenness. The method according to claim 1, wherein the inspection tool is placed on the main surface of the optical device so that the density pattern covers the optical unevenness. 2. The method according to claim 1, wherein the inspection tool includes a plurality of density patterns having different density levels. 6. The method of manufacturing an optical device according to claim 5, wherein the density patterns are arranged in the order of the density level. At the time of the determination, the series of the arranged density patterns is sequentially applied to the optical unevenness to be determined, and a comparison of density levels or a determination as to whether or not visible is performed. Item 7. The method for manufacturing an optical device according to Item 6. 2. The density pattern according to claim 1, wherein the density pattern includes a plurality of dots provided on the sheet or the film, and the density level of the density pattern is represented by an occupation rate of the dots per unit area. 3. Method of manufacturing optical device. The method of manufacturing an optical device according to claim 8, wherein the density pattern is formed by uniformly dispersing non-continuous circular or rectangular dots. The method of manufacturing an optical device according to claim 8, wherein the size of the dots constituting the density pattern is uniform. The method of manufacturing an optical device according to claim 8, wherein the size of the dot is 40 μm or less. The said inspection tool is comprised including the density pattern from which the occupation rate of the said dot differs, The occupation rate of the said dot has the said density pattern in the range of 3-45%, The said inspection tool. A method for manufacturing an optical device. 13. The inspection device according to claim 12, wherein the inspection tools are formed at intervals of 1 to 3% when the density level is low, and are formed at intervals of 5% when the density level is high. Method of manufacturing optical device. The method according to claim 1, wherein the optical device is a display panel. The method according to claim 1, wherein the optical device is a lighting device. An inspection tool for determining the degree of the density of optical unevenness appearing on the main surface of the optical device,
A base substrate made of a colorless transparent sheet or film,
An inspection tool provided on the base substrate and having a density pattern composed of an aggregate of dots having a size of 40 μm or less.