JPH11201865A - Apparatus and method for inspecting cell gap unevenness of liquid crystal panel and apparatus and method for measuring cell gap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve inspection accuracy and measurement accuracy in an apparatus and method for inspecting whether or not the cell gap unevenness of a liquid crystal panel is within an allowable range, and in an apparatus and method for measuring a cell gap. . SOLUTION: An image of a liquid crystal panel (101) is taken and RGB is obtained.
A color CCD camera (1) for outputting another light receiving signal,
Detecting means (10) for detecting R light quantity and G light quantity at a first point located at the center of the imaged surface and at four second points respectively located at the four corners from light receiving signals for each of RGB. A comparing means (10) for comparing the magnitudes of the R light quantity and the G light quantity for one point and setting R or G corresponding to the smaller light quantity as a test color, and a test color between each point. Output means (2) for outputting the difference in
0).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus and method for inspecting whether or not a cell gap of a liquid crystal panel is within an allowable range, and a cell gap measuring apparatus and method for measuring a cell gap of a liquid crystal panel. Belongs to the technical field.

[0002]

2. Description of the Related Art A liquid crystal panel displays an image as a whole panel by changing the light transmittance (hereinafter simply referred to as "transmittance") of each pixel of a liquid crystal layer in a liquid crystal cell. Here, the thickness of the liquid crystal layer in the liquid crystal cell (hereinafter, referred to as
If the “cell gap” is different at each position in the panel plane having a two-dimensional spread (ie, there is “cell gap unevenness”), the transmittance value in the same liquid crystal alignment state and the transmission with respect to the liquid crystal applied voltage are changed. The rate change characteristics are different at each position. Then, the display quality of each pixel varies depending on the cell gap unevenness, and the image quality of the entire liquid crystal panel deteriorates. For this reason, when commercializing this type of liquid crystal panel, for example, when the cell gap unevenness between the center part and the end part of the panel surface exceeds the allowable range necessary for maintaining image quality. In such a case, it is necessary to perform a cell gap unevenness test for determining that the liquid crystal panel is defective.

On the other hand, as a traditional product inspection of a liquid crystal panel, there is an inspection for uneven brightness on the entire surface of the liquid crystal panel. In this luminance unevenness inspection, the entire surface of the liquid crystal panel was C
Take a picture with a CD camera, detect the brightness at the center and the edge of the liquid crystal panel and compare the detected values numerically, or
The detected luminances are displayed two-dimensionally on a display screen and visually compared. Here, in particular, it is said that there is a relatively nearly linear relationship between the luminance and the cell gap in each pixel of the liquid crystal panel. For this reason, in the conventional method for inspecting the cell gap unevenness of the liquid crystal panel, Applying the brightness unevenness inspection method, it is determined whether or not the difference in the cell gap of the liquid crystal panel exceeds a predetermined allowable range based on the difference in brightness between the center and the end of the liquid crystal panel (that is, the cell gap unevenness is large). To check if it is defective).

[0004]

The cell gap value of a general or practical liquid crystal panel is often about 4 μm. Here, according to the study by the inventors of the present invention, according to the above-described conventional method of inspecting the cell gap of a liquid crystal panel based on the luminance, a gap smaller than about 3.5 μm or a gap larger than 4.5 μm has a higher luminance. And the cell gap are relatively linear, and it is possible to accurately determine whether or not the cell gap is within a predetermined allowable range based on the luminance.

However, in the range of about 4 ± 0.5 μm, the luminance does not change much even if the cell gap changes. Alternatively, there is a portion where the luminance is minimal with respect to the cell gap within the range of about 4 ± 0.5 μm (that is, a portion where the luminance is reduced and the rate of change of the luminance is also reduced). For this reason, there is a problem that it is fundamentally difficult to accurately inspect the cell gap unevenness based on the luminance difference particularly in a range of about 4 ± 0.5 μm which is practically necessary.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a highly accurate apparatus and method for inspecting cell gap unevenness of a liquid crystal panel, and a highly accurate cell gap measuring apparatus and method. .

[0007]

According to a first aspect of the present invention, there is provided an apparatus for inspecting cell gap unevenness of a liquid crystal panel, comprising: a surface light source; and a surface of the liquid crystal panel mounted on the surface light source. R (red), G (green), and B (blue) light, and a light receiving element for outputting a light receiving signal, and a first point located at the center and four corners located at the center of the surface of the liquid crystal panel, respectively. Detecting means for detecting the amount of R light and the amount of G light at the four second points, respectively, from the RGB received light signals; and one of the first and second points detected by the detecting means. Comparing means for comparing the magnitudes of the R light amount and the G light amount detected for R, and setting R or G corresponding to the smaller light amount as a test color; and the first point and the second point. The difference in the light amount of the test color between Characterized by comprising an output means for each output as the index value of the cap unevenness.

According to the liquid crystal panel cell gap unevenness inspection apparatus according to the first aspect, the light receiving element receives light of each of RGB from the liquid crystal panel mounted on the planar light source. Then, the light amount of R and the light amount of G at the first point located at the center of the surface of the liquid crystal panel and the four second points respectively located at the four corners are respectively detected by the detecting means from the received light signals for each of RGB. Is detected. Subsequently, the comparing unit compares the magnitude of the R light amount and the G light amount for one of the first point and the second point, and determines whether R or G corresponding to the smaller light amount is: This is set as the inspection color.
Here, according to the study by the inventors of the present application, the change characteristics of the R light amount (R transmittance) with respect to the cell gap are different from the change characteristics of the G light amount (G transmittance) with respect to the cell gap. In the range where the cell gap is about 4.2 μm and the cell gap is smaller than this, the rate of change of the amount of R light with respect to the cell gap is larger than the rate of change of the amount of G light with respect to the cell gap. That is, the light amount of R responds more sensitively to the increase and decrease of the cell gap. On the other hand, in a range where the cell gap is larger than about 4.2 μm, the rate of change of the light quantity of G with respect to the cell gap is larger than the rate of change of the light quantity of R with respect to the cell gap. It is more sensitive to the increase and decrease of the cell gap. Therefore, R or G set as the inspection color by the comparing means as described above is a color whose light amount responds more sensitively to the increase or decrease of the cell gap. Then, the difference in light amount between the first point and the second point of the test color (that is, R or G) set in this way is output as an index value of the cell gap unevenness by the output unit. You.

As a result, depending on whether or not the difference in the amount of light output as the index value of the cell gap unevenness falls within a predetermined allowable range set in advance by experience or calculation, the inspected liquid crystal panel is determined to be a cell. With respect to gap unevenness, it is possible to accurately inspect whether the product is good or defective.

According to a second aspect of the present invention, there is provided a liquid crystal panel cell gap unevenness inspection apparatus according to the first aspect of the present invention, wherein the output means comprises a separate one for each of the RGB. Color display means is provided, in which the output level of the light receiving signal of the inspection color out of the light receiving signals is pseudo-colored on the entire surface of the liquid crystal panel to display two-dimensionally.

According to the second aspect of the present invention, the output level of the light receiving signal of the inspection color is pseudo-colored over the entire surface of the liquid crystal panel by the color display means to provide a two-dimensional display. Is displayed. Therefore, the difference in cell gap (corresponding to the difference in the amount of light) between the center and the end of the liquid crystal panel can be visually recognized as the color difference on the screen of the color display means.

According to a third aspect of the present invention, there is provided an apparatus for inspecting uneven cell gap of a liquid crystal panel according to claim 1 or 2, wherein It is characterized by further comprising a judgment means for judging whether or not the difference in the light amount of the test color between each of the second points is within a predetermined allowable range.

According to the third aspect of the present invention, the difference in the light amount of the test color between the first point and the second point is set in advance by the determining means. It is determined whether it is within the allowable range. Therefore, the difference in the cell gap (corresponding to the difference in the amount of light) between the center and the end of the liquid crystal panel can be automatically compared numerically. For example, if the difference in light amount is within the allowable range, the result of determination that the product is good is automatically output. If the difference in light amount is not within the allowable range, the result of determination that the product is defective is automatically output. Is given.

According to a fourth aspect of the present invention, there is provided a method for inspecting cell gap unevenness of a liquid crystal panel, wherein R (red) G from the surface of the liquid crystal panel mounted on a planar light source is solved.
(Green) B (blue) A light receiving step of receiving another light and outputting a light receiving signal, a first point located at the center of the surface of the liquid crystal panel, and four second points located at four corners, respectively. Detecting a light amount of R and a light amount of G from the received light signals for each of RGB, and a light amount of R detected at one of the first point and the second point by the detecting step. A comparison step of comparing the magnitudes of the light amounts of G and G and setting R or G corresponding to the light amount of the smaller one as a test color, and the comparing step between the first point and the second point. An output step of outputting each of the differences in the light amounts of the test colors as index values of the cell gap unevenness.

According to the liquid crystal panel cell gap unevenness inspection method of the fourth aspect, the light receiving element receives light of each of RGB from the liquid crystal panel mounted on the planar light source. Then, the light quantity of R and the light quantity of G at the first point located at the center of the surface of the liquid crystal panel and the four second points respectively located at the four corners are respectively determined from the received light signals for each of the RGB in the detection step. Is detected. Subsequently, in the comparison step, the magnitude of the light amount of R and the light amount of G are compared for one of the first point and the second point, and R or G corresponding to the smaller light amount is determined as: This is set as the inspection color.
Then, the light amount difference between the first point and the second point of the test color (that is, R or G) set in this way is output as an index value of the cell gap unevenness in the output step. You.

As a result, similarly to the case of the cell gap unevenness inspection apparatus of the present invention, whether the inspected liquid crystal panel is good or defective with respect to the cell gap unevenness can be accurately inspected.

According to a fifth aspect of the present invention, there is provided an apparatus for measuring a cell gap of a liquid crystal panel, comprising:
R from the surface of the liquid crystal panel placed on the planar light source
(Red) G (green) B (blue) A light receiving element that receives another light and outputs a light receiving signal, and four first light emitting elements located at the center of the surface of the liquid crystal panel and four light emitting elements located at four corners, respectively. Detecting means for detecting the amount of R light and the amount of G light at two points from the received light signals for each of RGB, and detecting one of the first point and the second point by the detecting means; Comparing means for comparing the magnitudes of the R light quantity and the G light quantity, and setting R or G corresponding to the smaller light quantity as a test color; and the cell gap corresponding to each of the R and G light quantities. Storage means for storing a look-up table in which each value of 予 め is set in advance, and the value of the cell gap corresponding to the light amount of the test color at each of the first point and the second point is looked up. Read from the table Characterized by comprising an output means for each output as the cell gap measurement at said first point and the second point, respectively.

According to the liquid crystal panel cell gap measuring device according to the fifth aspect, the light receiving element receives light of each of RGB from the liquid crystal panel mounted on the planar light source.
Then, the light amount of R and the light amount of G at the first point located at the center of the surface of the liquid crystal panel and the four second points respectively located at the four corners are respectively detected by the detecting means from the received light signals for each of RGB. Is detected. Subsequently, the comparing unit compares the magnitude of the R light amount and the G light amount for one of the first point and the second point, and determines whether R or G corresponding to the smaller light amount is: This is set as the inspection color. Here, as described above, R or G set as the inspection color by the comparing means is a color whose light amount responds more sensitively to the increase or decrease of the cell gap. On the other hand, the storage means stores a look-up table in which each value of the cell gap for each of the light amounts of R and G is set in advance. Then, the value of the cell gap corresponding to the light amount at each of the first point and the second point of the test color (that is, R or G) set by the comparing unit is obtained from a lookup table stored in the storage unit. It is read and output as a cell gap measurement at each of the first point and the second point.

As a result, depending on the size of the cell gap,
The cell gap can be accurately measured using a more appropriate R light amount or G light amount.

According to a sixth aspect of the present invention, there is provided an apparatus for measuring a cell gap of a liquid crystal panel according to the fifth aspect of the present invention, wherein the storage means and the output means include the look-up means. A PROM (programmable read only memory) that stores a table and is programmed to read and output the cell gap value corresponding to the light amount of the test color from the lookup table. Features.

According to the liquid crystal panel cell gap measuring device of the present invention, the look-up table is a PROM.
The value of the cell gap corresponding to the light amount of the test color is read from the look-up table and output by the PROM. Thus PROM
The cell gap can be quickly measured by the storage means and the output means constituted by.

According to a seventh aspect of the present invention, there is provided a method for measuring a cell gap of a liquid crystal panel, wherein R (red), G (green), and B (blue) from the surface of the liquid crystal panel mounted on a planar light source are solved. A) a light-receiving step of receiving another light and outputting a light-receiving signal; and R light amount and G at a first point located at the center of the surface of the liquid crystal panel and at four second points located at four corners, respectively. Detecting the amount of light from each of the RGB light-receiving signals, and detecting R at one of the first point and the second point by the detecting step.
Comparing the magnitude of the light quantity of G with the magnitude of the light quantity of G, and setting R or G corresponding to the light quantity of the smaller quantity as the inspection color; and comparing the first point and the second point with each other. The cell gap value corresponding to the light amount of the inspection color is read from a lookup table in which the cell gap values corresponding to the R and G light amounts are set in advance and stored in storage means, An output step of outputting each of the cell gap measurement values at the first point and the second point, respectively.

According to the method of measuring a cell gap of a liquid crystal panel according to the present invention, the light receiving element receives light of each of RGB from the liquid crystal panel mounted on the planar light source.
Then, the light quantity of R and the light quantity of G at the first point located at the center of the surface of the liquid crystal panel and the four second points respectively located at the four corners are respectively determined from the received light signals for each of the RGB in the detection step. Is detected. Subsequently, in the comparison step, the magnitude of the light amount of R and the light amount of G are compared for one of the first point and the second point, and R or G corresponding to the smaller light amount is determined as: This is set as the inspection color. Here, as described above, R or G set as the inspection color by the comparing means is a color whose light amount responds more sensitively to the increase or decrease of the cell gap. On the other hand, the storage means stores a look-up table in which each value of the cell gap for each of the light amounts of R and G is set in advance. Then, the value of the cell gap corresponding to the light amount at each of the first point and the second point of the test color (that is, R or G) set in the comparison step is obtained from the lookup table stored in the storage means. It is read and output as a cell gap measurement at each of the first point and the second point.

As a result, as in the case of the above-described cell gap measuring apparatus of the present invention, the cell gap can be accurately measured by using a more appropriate R light amount or G light amount according to the size of the cell gap. .

The operation and other advantages of the present invention will become more apparent from the embodiments explained below.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows the overall configuration of a cell gap unevenness inspection apparatus having the function of a cell gap measurement apparatus according to the present invention.

In FIG. 1, an inspection apparatus 100 includes a color CCD camera 1 as an example of a light receiving element, a personal computer (personal computer) 10, and a color monitor 2.
0.

The color CCD camera 1 captures an image of the entire surface of a liquid crystal panel 101 placed on a backlight 110 as an example of a planar light source on a predetermined photographing table, and outputs RGB images.
It is configured to output another light receiving signal.

The personal computer 10 has an external input terminal 11 to which light receiving signal lines for each of RGB from the color CCD camera 1 are connected, and a light receiving signal for each of RGB from the color CCD camera 1 via the external input terminal 11, respectively. An FD (floppy disk) drive 13 for reading an inspection and measurement program and a later-described lookup table from the input interface board 12 and the floppy disk 13a and storing various inspection and measurement result data on the floppy disk 13a. And a CPU (Central Processing Unit) 15 on which an inspection and measurement program described later is executed.
It is comprised including.

The CPU 15 has a floppy disk 13a.
As shown in FIG. 2, the liquid crystal panel 101 functions as an example of a detection unit according to an inspection and control program read from the LCD or stored in a built-in hard disk. The light amount of R and the light amount of G at the first point P1 located at the center and the four second points P2 to P5 respectively located at the four corners are respectively detected from the RGB light receiving signals.

Referring again to FIG. 1, the CPU 15 also functions as an example of the comparing means according to the inspection and control program, and operates as one of the first point P1 and the second points P2 to P5 (for example, The light quantity of R and the light quantity of G detected for only one point P1) are compared with each other, and R or G corresponding to the smaller light quantity is set as the inspection color. That is, the transmittance (light quantity) of R
In the case of> G transmittance (light quantity), R is set as a test color, and in the case of R transmittance (light quantity) <G transmittance (light quantity), G is set as a test color. When both are equal (although extremely rare), R or G is set as the inspection color.

The CPU 15 also functions as an example of an output unit together with the color monitor 20 in accordance with the inspection and control program, and outputs the first point P1 and the second point P1.
The difference in light amount of the test color (R or G) between each of 2 to P5 is output as an index value of the cell gap unevenness.

On the other hand, floppy disks 13a and F
An example of a storage unit is configured from the D drive 13.
The floppy disk 13a stores a look-up table in which each value of the cell gap for each of the R and G light amounts is set in advance. And the CPU 15
The value of the cell gap corresponding to the light amount at each of the first point and the second point of the inspection color (that is, R or G) set by FD is obtained from the lookup table stored in the floppy disk 13a by the CPU 15 from the FD. Drive 13
Is read via The cell gap values at the first point P1 and the second points P2 to P5 thus read are output as cell gap measurement values.

Here, in the liquid crystal panel 101, the propagation of light in the liquid crystal sandwiched between a pair of substrates is generally Berrem.
It can be calculated by the 4 × 4 matrix method of an. Further, in the case of a TN (twisted nematic) mode in which the twist angle of the liquid crystal is 90 °, which is defined by the alignment direction of the alignment film provided on the opposing surfaces of the pair of substrates of the liquid crystal panel 101 and the properties of the liquid crystal, It can be easily calculated by the Gooch-Tarry equation as shown below.

That is, in the normally black mode, the transmittance of the liquid crystal cell is T = Sin ² (π / 2 × (1 + u ² ) ^1/2 ) / (1 + u ² ) where u = 2Δnd / λ (n: Refractive index, d: cell gap, λ: wavelength In the normally white mode, the transmittance of the liquid crystal cell is T = 1− ｛Sin ² (π / 2 × (1 + u ² ) ^1/2 ) / (1)
+ U ² )｝.

FIG. 3 is a characteristic diagram showing the relationship between the cell gap of the liquid crystal panel 101 and the transmittance (light amount) of each of the RGB colors simulated or experimentally obtained based on such calculations.

As shown in FIG. 3, the change characteristic of the transmittance (light amount) of R with respect to the cell gap d, the transmittance (light amount) of G
And the change characteristic of the transmittance (light quantity) of B are different from each other. In the range where the cell gap d is about 4.2 μm and the cell gap d is smaller than this, the rate of change of the R light quantity with respect to the cell gap d is smaller than the G light quantity with respect to the cell gap d. The rate of change is larger than the rate of change, and it can be seen that the light amount of R responds more sensitively to the increase and decrease of the cell gap. On the other hand, in a range where the cell gap d is larger than about 4.2 μm, the rate of change of the amount of G light with respect to the cell gap d is greater than the rate of change of the amount of R light with respect to the cell gap d. It can be seen that the light amount of (1) responds more sensitively to the increase / decrease of the cell gap d. Further, the light amount of B has a local minimum value when the cell gap d is about 3 μm and a local maximum value at about 4.6 μm. Therefore, it is theoretically possible to specify the cell gap from the transmittance of B. It turns out that neither is possible (even in practice).

Accordingly, as described above, R or G set as a test color by the CPU 15 functioning as a comparing means according to the test and measurement program responds more sensitively to the increase or decrease of the cell gap d. Color.

Then, the first point P1 and the second points P2 to P5 of the test color (that is, R or G) set in this way.
The difference in light amount between each of them is calculated by the CPU 15 and displayed on the screen of the color monitor 20, for example, as an index value of cell gap unevenness.

As a result, according to the present embodiment, the difference in the amount of light (transmittance) displayed on the screen of the color monitor 20 as the index value of the cell gap unevenness is determined by a predetermined empirically or calculated value. Tolerance (for example, ± 0.1 μm)
m), it is possible to accurately inspect whether the inspected liquid crystal panel 101 is good or defective with respect to the cell gap unevenness.

Further, in this embodiment, in particular, for example, FIG.
The look-up table indicating the relationship between the transmittance (light amount) of R and the cell gap d and the relationship between the transmittance (light amount) of B and the cell gap d as shown in (1) are stored in the floppy disk 13a in advance. . Then, the first point P1 of the test color (ie, R or G) set by the CPU 15
And the value of the cell gap d corresponding to the light amount at each of the second points P2 to P5 are read out from the look-up table, and the cell gap measurement at the first point P1 and the second points P2 to P5 is performed. Each value is output as a value (measured value of cell gap at five points in total).

As a result, according to the present embodiment, the first point P1 is determined by using a more appropriate R light amount (transmittance) or G light amount (transmittance) according to the size of the cell gap d. And the cell gap d at the second points P2 to P5 can be accurately measured.

In the present embodiment, in particular, the CPU 15 and the color monitor 20 functioning as output means make the output level of the inspection color light receiving signal among the RGB light receiving signals into a pseudo color for the entire surface of the liquid crystal panel 101. 2
It is configured to display a dimension. FIG. 4 shows an example of such a pseudo-colored two-dimensional display.

As shown in FIG. 4, the screen 20a of the color monitor 20 has cells smaller than the cell gap value at the first point P1 located at the center of the surface of the liquid crystal panel 101, for example. A pseudo color surface 102 is displayed in which a portion having a gap is red, a portion having a cell gap larger than that is yellow, and a difference from the value of the cell gap at the first point P1 corresponds to the color density. Have been.

As a result, according to the inspection apparatus 100, the difference in the cell gap d between the center and the end of the liquid crystal panel 101 can be visually recognized as the color difference on the screen 20a of the color monitor 20.

Further, in the present embodiment, the CPU 15 also functions as an example of a judging means in accordance with the inspection and measurement program, and the inspection color between the first point P1 and each of the second points P2 to P5. It is automatically determined whether the difference between the light amounts of R or G) is within a preset allowable range.
As the determination result, a column indicating the determination result is provided on the display screen for each cell gap between each point, and text data such as "good" or "defective" is displayed in this column. Alternatively, when even one light amount difference that is not within the allowable range exists, text data such as “defective product” may be displayed as a determination result for the entire liquid crystal panel 101. In the upper left area of the display screen 20a shown in FIG. 4, text data 20b indicating "defective" is displayed as such a determination result.

As described above, the inspection apparatus 100 according to the present embodiment
According to this, it is convenient not only that the difference between the cell gap d at the center and the end of the liquid crystal panel 101 can be automatically compared numerically, but also that the judgment result of a non-defective or defective product is automatically output. .

In the CPU 2, as a result of comparing the light amount of R and the light amount of G, if the light amount of G is not smaller than the light amount of R, the light amount of G is set as the inspection color.
Also in this case, the light amount of R is set as a test color,
Inspection of cell gap unevenness or measurement of cell gap may be performed using the amount of light.

Next, the procedure of the cell gap unevenness inspection and the cell gap measurement using the inspection apparatus 100 of the present embodiment will be described. It is assumed that a lookup table indicating the value of each cell gap corresponding to each of the above R and G light amounts is stored in advance on the floppy disk 13a loaded into the inspection apparatus 100.

First, before actually taking an image of the liquid crystal panel 101, the white balance of the color CCD camera 1 is obtained. In this process, before the liquid crystal panel 101 is mounted on the backlight 110 on the photographing table, only the backlight 110 is mounted on the photographing table, and light receiving signals are obtained for each of RGB. Set the gain of each color so that they are the same. By taking the white balance in this way, it is possible to correct light source unevenness and lens unevenness in the received light signal regardless of the color temperature.

Next, the liquid crystal panel 101 is placed on the backlight 110 on the photographing stand, and the entire surface of the liquid crystal panel 101 is imaged by the color CCD camera 1 to obtain RGB.
Another light receiving signal is output. Then, the R light amount and the G light amount at the first point P1 and the second points P2 to P5 on the imaged surface are detected by the personal computer 10 from the received light signals for each of RGB, and subsequently, One point P1 and one of the second points P2 to P5 (for example, the first point P1
Regarding 1), the magnitudes of the R light quantity and the G light quantity are compared, and R or G corresponding to the smaller light quantity is set as the inspection color. As described above, R or G set as the inspection color is a color whose light amount responds more sensitively to the increase or decrease of the cell gap d as described above.

Next, the difference in light amount between the first point P1 and the second points P2 to P5 of the test color (that is, R or G) set in this manner is indicated by the screen of the color monitor 20. Above are displayed as index values of cell gap unevenness.

In parallel with this, the value of the cell gap corresponding to the light quantity at the first point P1 and the second points P2 to P5 of the test color (that is, R or G) is stored in the floppy disk 13a. Are read out from the lookup table thus obtained and output as cell gap measurement values (five measurement values) at the first point P1 and the second points P2 to P5, respectively.

The examiner looks on the color monitor 20 for a more appropriate difference in the amount of R light or the amount of G light in accordance with the size of the cell gap. It is determined whether it is within the allowable range.

As described above, the inspected liquid crystal panel 1
It is possible to accurately inspect whether the cell No. 01 is a non-defective or non-defective cell gap.

Further, the cell gap can be accurately measured by using a more appropriate R light amount or G light amount according to the size of the cell gap.

In the present embodiment, in particular, as described above, the output level of the light receiving signal of the inspection color is displayed on the screen 20a of the color monitor 20 in a pseudo color on the entire surface of the liquid crystal panel 101, as described above. The dimension is displayed (see FIG. 4). Therefore, the inspector who sees this can see the
Can be visually recognized as a color difference on the screen of the color monitor 20.

In the present embodiment, the first point P1 and the second points P2 to P2
It is automatically determined whether or not the difference in the light amount of the test color between each of P5 and P5 is within the allowable range, and the determination result is displayed on the screen 20a of the color monitor 20. Therefore, it is convenient for the inspector to easily know whether the inspected liquid crystal panel 101 is non-defective or non-defective with respect to the cell gap non-uniformity.

(Second Embodiment) FIG. 5 shows the overall configuration of a cell gap unevenness inspection apparatus having the function of a cell gap measurement apparatus according to the present invention. In FIG. 5, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 5, the inspection apparatus 200 includes a color CCD camera 1, an A / D converter 31, an RG comparison and selector 33, a PROM (R) 35, and a PROM (G).
36, an input changeover switch 37, and a gap measurement and gap unevenness inspection output unit 38.

When the A / D converter 31 receives the RGB received light signals from the color CCD camera 1, the A / D converter 31 AD-converts these signals and outputs RGB digital signals. The A / D converter 31 is configured to always pass the R and G digital signals to the RG comparison and selector 33.

The RG comparison and selection unit 33 functions as an example of a detection unit and a comparison unit in accordance with the inspection and control logic, and converts the A / D-converted digital signals of RGB into the liquid crystal surface 101a of the liquid crystal panel 101 as shown in FIG. The light amount of R and the light amount of G at the first point P1 and the four second points P2 to P5 shown in FIG. Furthermore, the first
Of the point P1 and one of the second points P2 to P5 (for example, only the first point P1) is compared with the amount of light (transmittance) of R and the amount of light (transmittance) of G detected. In addition, R or G corresponding to the smaller light amount is set as the inspection color.

The PROM (R) 35 constitutes an example of a storage means, and stores a lookup table in which each value of the cell gap for each light amount of R is set in advance. Then, the PROM (R) 35 is programmed so that the value of the cell gap d corresponding to the light amount at the first point P1 and each of the second points P2 to P5 is read from the stored lookup table. I have.

The PROM (G) 36 constitutes an example of a storage means, and stores a look-up table in which each value of the cell gap for each light amount of G is set in advance. Then, the PROM (G) 36 is programmed so that the value of the cell gap d corresponding to the light amount at the first point P1 and each of the second points P2 to P5 is read from the stored lookup table. I have.

Then, the RG comparison of the cell gap measurement values at the first point P1 and the second points P2 to P5 read out in this manner and the inspection color (ie, the inspection color set by the selector 33) One corresponding to R or G) is input to a gap measurement and gap unevenness inspection output unit 38 via an input changeover switch 37.

The gap measurement and gap unevenness inspection output unit 38 corresponds to the light quantity at the first point P1 and the second points P2 to P5 of the inspection color (that is, R or G) input as described above. Is output on a display screen or on paper. At the same time, the gap measurement and gap unevenness inspection output device 38 outputs the first point P
The difference of the cell gap based on the light amount of the test color (R or G) between the first and second points P2 to P5 is output as an index value of the cell gap unevenness on a display screen or on paper. It is configured.

Therefore, as in the case of the first embodiment, R or G, which is set as the inspection color by the RG comparison and selector 33, is more sensitive to the increase or decrease of the cell gap d. It will be the color of the responder. As a result, according to the present embodiment, according to the magnitude of the cell gap d,
More appropriate R light intensity (transmittance) or G light intensity (transmittance)
Can be used to quickly and accurately measure the cell gap d at the first point P1 and the second points P2 to P5. Further, whether or not the difference between the cell gap output from the gap measurement and gap unevenness inspection output unit 38 as an index value of the cell gap unevenness is within a predetermined allowable range is determined based on whether the inspected liquid crystal panel is used. It is possible to quickly and accurately inspect whether or not the cell 101 is a non-defective or defective cell gap.

In the first and second embodiments described above, the difference in the spectral characteristics of the color CCD camera 1, the difference in the color temperature of the backlight 110 mounted on the photographing table, and the like are shown in FIG. The characteristics shown vary. Therefore, the above-mentioned look-up table is prepared in advance for one characteristic as shown in FIG. 3, and at the time of actual inspection, the spectral characteristics of the color CCD camera 1 and the parameters such as the color temperature of the backlight 110 are determined. It is preferable to correct each cell gap value read from the lookup table according to the difference. For example, in the case of the first embodiment, such correction is performed in the inspection and measurement program that controls the CPU 2 by adding each cell gap value read from the look-up table and the parameters such as the above-described spectral characteristics. What is necessary is just to incorporate a correction program using a predetermined function that inputs the following. Alternatively, in the case of the second embodiment, the PROM (R) 35 or PRO
Such a correction program may be incorporated in the M (G) 36. Further, the shading of the lens of the color CCD camera 1 (peripheral luminance unevenness), the material of the liquid crystal, and the like may be corrected.

A color CCD is used as an example of the light receiving element.
Although the camera has been described, other solid-state imaging devices, television cameras, optical fibers, and the like can be used as light receiving devices. In particular, when a TV camera of the NTSC system or the PAL system is used as a light receiving element, the NT camera is used.
If the present invention is applied as a light receiving signal by extracting the R and G color difference signals included in the SC signal and the PAL signal, it is possible to measure the cell gap based on the color difference signal and output an index value indicating the cell gap unevenness. Is possible. Furthermore, even in a configuration in which not only transmitted light but also reflected light from a liquid crystal panel is received, it is possible to measure a cell gap or to output an index value indicating cell gap unevenness as in the case of using transmitted light. .

As described above, according to the first and second embodiments, the cell gap unevenness of the liquid crystal panel can be inspected with high accuracy, and the cell gap can be measured with high accuracy. .

[0072]

According to the liquid crystal panel cell gap unevenness inspection apparatus and method of the present invention, it is possible to accurately inspect whether the liquid crystal panel is good or defective with respect to the cell gap unevenness. In addition, by making the output level of the light receiving signal of the inspection color pseudo-color and displaying it two-dimensionally, the cell gap unevenness can be visually recognized. Further, by determining whether or not the difference between the light amounts of the test colors is within an allowable range, it is possible to automatically determine whether the liquid crystal panel is a non-defective or defective product.

According to the apparatus and method for measuring the cell gap of a liquid crystal panel of the present invention, the cell gap of the liquid crystal panel can be accurately measured by using the R or G light amount. Furthermore, by storing the look-up table in the PROM, the cell gap can be measured quickly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a first embodiment of an inspection apparatus according to the present invention.

FIG. 2 is a perspective view of a liquid crystal panel inspected by the inspection device of FIG.

FIG. 3 is a characteristic diagram showing a relationship between a cell gap and a transmittance (light amount) of each color in a liquid crystal panel.

FIG. 4 is a plan view showing an example of a display screen of a color monitor provided in the inspection device of FIG.

FIG. 5 is a block diagram showing an overall configuration of an inspection apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Color CCD camera 10 ... PC 11 ... External input terminal 12 ... Interface board 13 ... FD drive 13a ... Floppy disk 15 ... CPU 20 ... Color monitor 20a ... Display screen 31 ... A / D converter 33 ... RG comparison and selector 35 PROM (R) 36 PROM (G) 37 Input switch 38 Gap measurement and unevenness inspection output device 100 Inspection device 110 Backlight 101 Liquid crystal panel 101a Surface of liquid crystal panel 200 Inspection device

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Koichi Koshikawa 1-3-6 Higashiyama 1-804, Meguro-ku, Tokyo 804

Claims (7)

[Claims] 1. A planar light source; and R from a surface of a liquid crystal panel mounted on the planar light source.
(Red) G (green) B (blue) A light receiving element that receives another light and outputs a light receiving signal, and a first point located at the center of the surface of the liquid crystal panel and four light emitting elements located at four corners, respectively. R light amount and G at point 2
Detecting means for detecting the amount of light from each of the RGB light-receiving signals; and detecting the amount of light of R and the amount of light of G detected by the detecting means for one of the first point and the second point. Comparing means for comparing the magnitudes and setting R or G corresponding to the light amount that is not smaller as the test color; and comparing the light amount of the test color between the first point and the second point. Output means for outputting the difference as an index value of the cell gap unevenness, respectively. 2. The color image display device according to claim 1, wherein the output unit is a color display unit that pseudo-colors the output level of the light receiving signal of the inspection color out of the light receiving signals for each of the RGB on the entire surface of the liquid crystal panel and displays the two-dimensionally. 2. The inspection apparatus for uneven cell gaps of a liquid crystal panel according to claim 1, wherein: 3. A determination means for determining whether or not a difference in the light amount of the test color between the first point and the second point is within a preset allowable range. 3. The inspection apparatus for uneven cell gaps of a liquid crystal panel according to claim 1, wherein: 4. A light receiving step of receiving R (red), G (green), and B (blue) different lights from a surface of a liquid crystal panel mounted on a planar light source and outputting a light reception signal, and the liquid crystal panel. Of the R and G at a first point located at the center of the surface and four second points respectively located at the four corners.
A detecting step of detecting the amount of light of each of the RGB from the received light signals for each of RGB, and a light amount of R and a light amount of G detected at one of the first point and the second point by the detecting step. A comparison step of comparing R and G corresponding to the light amount of the smaller one as the test color, and comparing the light amount of the test color between the first point and the second point. An output step of outputting the difference as an index value of the cell gap unevenness, respectively. 5. A planar light source; and R from a surface of a liquid crystal panel mounted on the planar light source.
(Red) G (green) B (blue) A light receiving element that receives another light and outputs a light receiving signal, and a first point located at the center of the surface of the liquid crystal panel and four light emitting elements located at four corners, respectively. R light amount and G at point 2
Detecting means for detecting the amount of light from each of the RGB light-receiving signals; and detecting the amount of light of R and the amount of light of G detected by the detecting means for one of the first point and the second point. Comparing means for comparing the magnitudes and setting the R or G corresponding to the light quantity which is not smaller as the test color; and the lookup in which the respective values of the cell gap for the respective light quantities of the R and G are set in advance. Storage means for storing a table; reading a value of the cell gap corresponding to a light amount of the test color at each of the first point and the second point from the look-up table; A cell gap measurement device for a liquid crystal panel, comprising: output means for outputting a cell gap measurement value at each of the second points. 6. The storage means and the output means store the look-up table and read out and output the value of the cell gap corresponding to the light amount of the test color from the look-up table. The cell gap measuring device for a liquid crystal panel according to claim 5, comprising a programmable read only memory (PROM). 7. A light receiving step of receiving R (red), G (green), and B (blue) different lights from the surface of a liquid crystal panel mounted on a planar light source and outputting a light reception signal, and the liquid crystal panel. Of the R and G at a first point located at the center of the surface and four second points respectively located at the four corners.
A detecting step of detecting the amount of light of each of the RGB from the received light signals for each of RGB, and a light amount of R and a light amount of G detected at one of the first point and the second point by the detecting step. A comparison step of comparing R and G corresponding to the light amount which is not smaller and comparing the magnitude with the light amount of the inspection color at each of the first point and the second point. The value of the cell gap is read out from a look-up table in which each value of the cell gap for each of the light amounts of R and G is set in advance and stored in storage means, and the first point and the second point are read out. Outputting a cell gap measurement value at each of the above points.