JP6581338B2 - Liquid crystal alignment film state measurement device - Google Patents

Description

  The present invention relates to a liquid crystal alignment film state measurement apparatus that measures the state of an alignment film formed on the surface of a glass substrate constituting a liquid crystal panel.

  The liquid crystal panel is configured to include a liquid crystal layer between two glass substrates. An alignment film made of, for example, polyimide is formed on the surface of the glass substrate on the liquid crystal layer side, and liquid crystal molecules are arranged along the alignment direction of the alignment film. If the alignment state of the alignment film is poor, the alignment state of the liquid crystal molecules is also deteriorated, and as a result, the display performance of the liquid crystal panel is impaired. Therefore, in order to identify a glass substrate having a poor alignment film state as a defective product, development of a technique for measuring the state of the alignment film is underway. For example, Patent Document 1 includes various units for moving or rotating a sample stage that holds a glass substrate, so that the evaluation of the alignment state of the alignment film over a wide area can be performed at high speed and with high accuracy. This technique is disclosed.

Japanese Patent Laid-Open No. 2002-365637

However, there are rare cases where the region where the alignment film state is deteriorated over a wide range on the surface of the glass substrate is wide, and even if the alignment film state is deteriorated, the region is the same as the surface of the glass substrate. It is almost a part. Therefore, in the conventional technique for measuring the state of the alignment film over a wide area of the glass substrate, it is possible to finally measure a region where the state of the alignment film is deteriorated, but the state of the alignment film is good. Since the measurement operation is performed also on the area, most of the measurement operation is wasted and the efficiency is poor.
Therefore, the present invention provides a liquid crystal alignment film state measurement apparatus capable of efficiently measuring a region where the state of the alignment film is deteriorated on the surface of a glass substrate.

The liquid crystal alignment film state measuring device according to the present invention is a device for measuring the state of the alignment film formed on the surface of the glass substrate constituting the liquid crystal panel, and includes a measurement region specifying function unit and a film state measuring function unit And a transfer function unit. The measurement region specifying function unit specifies, as the measurement region, a region in the surface of the glass substrate where an indication that the state of the alignment film has deteriorated appears. The film state measuring function unit measures the state of the alignment film formed in the measurement region specified by the measurement region specifying function unit. The transfer function unit is for transferring the glass substrate from the measurement region specifying function unit to the film state measuring function unit, and integrally connecting the measurement region specifying function unit and the film state measuring function unit. . The measurement region specifying function unit includes an irradiation unit that irradiates the entire surface of the glass substrate, and an imaging unit that images the entire surface of the glass substrate while being irradiated by the irradiation unit, and is imaged by the imaging unit. The measurement region is specified based on the captured image data, and a pair of leg portions whose base end portions are rotatably attached to the transfer function portion and the distal end portions of the leg portions are connected to each other. And an imaging direction adjusting unit in which the imaging unit is attached to the coupling unit so that the imaging direction of the imaging unit can be adjusted.

  According to this configuration, the measurement of the state of the alignment film is not performed over a wide region of the surface of the glass substrate, but there is an indication that the state of the alignment film is a part of the surface of the glass substrate and is deteriorated. This is done only for the measurement area that appears. Thereby, the measurement of the area | region where the state of the alignment film has deteriorated on the surface of a glass substrate can be performed efficiently.

FIG. 1 is a diagram schematically illustrating a configuration example of a liquid crystal alignment film state measurement apparatus according to an embodiment (part 1); FIG. 2 is a diagram schematically illustrating a configuration example of a liquid crystal alignment film state measurement apparatus according to an embodiment (part 2); Sectional drawing which shows the structural example of a liquid crystal panel roughly Flowchart showing an example of a measurement operation by the liquid crystal alignment film state measurement device

  Hereinafter, an embodiment of a liquid crystal alignment film state measuring apparatus according to the present invention will be described with reference to the drawings. The liquid crystal alignment film state measurement device 10 illustrated in FIG. 1 includes a transfer function unit 11, a measurement region specifying function unit 12, and a film state measurement function unit 13. Hereinafter, the state measuring device 10 of the liquid crystal alignment film is simply referred to as a “state measuring device 10”. As illustrated in FIG. 3, the liquid crystal panel 100 is configured to include a liquid crystal layer 103 between two glass substrates 101 and 102, that is, between the array substrate 101 and the color filter substrate 102. An alignment film 104 made of polyimide, for example, is formed on the surface of the glass substrates 101 and 102 on the liquid crystal layer 103 side. The state measuring device 10 is a device that measures the state of the alignment film 104 formed on the surfaces of the glass substrates 101 and 102 constituting the liquid crystal panel 100 as described above. The configuration will be described in detail below. The method for aligning the alignment film 104 may be a known rubbing method or a UV light source method.

The state measuring apparatus 10 includes an upstream portion 10A mainly including the measurement region specifying function unit 12 and a downstream portion 10B mainly including the film state measuring function unit 13. The state measuring device 10 has a configuration in which the upstream portion 10A and the downstream portion 10B are integrally connected by the transfer function portion 11.
The transfer function unit 11 moves the measurement stage 11b on which the glass substrate is placed in two directions, that is, the first transfer direction D1 from the measurement region specifying function unit 12 toward the film state measurement function unit 13, and the film state measurement function unit 13. It is a functional part for mechanically transferring in the second transfer direction D2 toward the measurement area specifying function part 12 from the center.

  Specifically, the transfer function unit 11 includes a measurement stage 11b on a long base 11a. The measurement stage 11b is provided so as to be movable along the longitudinal direction of the base portion 11a. A glass substrate (not shown) on which an alignment film is formed is placed on the measurement stage 11b with the alignment film side facing up. The transfer function unit 11 moves the measurement stage 11b to the upstream portion 10A side as illustrated in FIG. 1 in the measurement region specifying process described in detail later.

  On the other hand, the transfer function unit 11 moves the measurement stage 11b to the downstream portion 10B side as illustrated in FIG. 2 when shifting from the measurement region specifying process to a film state measurement process described in detail later. As a result, the glass substrate on the measurement stage 11b is transferred from the measurement region specifying function unit 12 to the film state measurement function unit 13 in accordance with the shift from the measurement region specifying process to the film state measuring process. In addition, the moving speed of the measurement stage 11b, in other words, the moving speed of the glass substrate can be appropriately changed according to the size and shape of the glass substrate that is a sample, the type of the alignment film, and the like.

The measurement region specifying function unit 12 specifies, as a measurement region, a region where an indication that the alignment film is in a poor state appears on the surface of the glass substrate placed on the measurement stage 11b by the measurement region specifying process. It is a functional part. In this case, the measurement region specifying function unit 12 includes an irradiation unit 12a and an imaging unit 12b.
The irradiation unit 12a is configured by, for example, an LED illumination device and irradiates the entire surface of the glass substrate on the measurement stage 11b. In this case, the irradiation part 12a is installed in the state which inclined below toward the opposite side to the downstream part 10B. Therefore, the light emitted from the irradiation unit 12a is obliquely directed from the upper side on the downstream unit 10B side to the lower side of the downstream unit 10A with respect to the glass substrate placed on the measurement stage 11b, as indicated by a dashed line L1. Incident. In addition, it is possible to adjust the irradiation direction L1 suitably by adjusting the installation direction of the irradiation part 12a.

  The imaging unit 12b is configured by, for example, a camera, and images the entire surface of the glass substrate in a state where the glass substrate on the measurement stage 11b is irradiated by the irradiation unit 12a. And the imaging part 12b outputs the imaging data obtained by the imaging process. In this case, the imaging unit 12b outputs, for example, bitmap format data having a luminance value of 256 gradations as the imaging data. Note that the imaging data output by the imaging unit 12b may be in a data format other than the bitmap format.

  In this case, the imaging unit 12b is provided at the distal end of the imaging direction adjustment unit 14. If demonstrating it more concretely, the imaging direction adjustment part 14 is provided with a pair of leg part 14a and the connection part 14b which connects between the front-end | tip parts of these leg parts 14a. In the figure, only one leg portion 14a on the front side is shown. The leg portion 14a is pivotally attached to both side portions of the transfer function portion 11 in the short direction. Therefore, as shown by arrows R1 and R2, the entire imaging direction adjustment unit 14 is configured to be rotatable about the base end portion of the leg portion 14a.

  The imaging unit 12b is attached to a connecting part 14b that connects the distal ends of the leg parts 14a, and is provided so that the imaging direction P1 is directed toward the base end side of the leg parts 14a. The imaging unit 12b is installed such that the imaging direction P1 is parallel to the longitudinal direction of the leg unit 14a. According to this configuration, a line along the imaging direction P1 of the imaging unit 12b extends between the pair of leg portions 14a along the longitudinal direction of the leg portion 14a. Therefore, the imaging unit 12b has a configuration in which the imaging region is not blocked by the leg unit 14a. Further, by adjusting the rotation angle of the imaging direction adjusting unit 14, the imaging direction P1 of the imaging unit 12b can be adjusted as appropriate.

  Based on the imaging data captured by the imaging unit 12b, the measurement region specifying function unit 12 shows signs that the alignment film is in a poor condition on the surface of the glass substrate placed on the measurement stage 11b. It has a function of extracting an area and specifying the area as a measurement area. Here, the reflected light irradiated from the irradiation unit 12a and reflected by the glass substrate is reflected in different modes depending on the difference in the fine uneven state on the surface of the alignment film of the glass substrate. For this reason, for example, the luminance value of the imaging data differs at a location where the thickness of the alignment film is uneven or a location where the orientation direction of the grooves is not uniform. That is, a sign that the state of the alignment film is deteriorated appears in the imaging data.

  Therefore, the measurement region specifying function unit 12 extracts pixels whose luminance values are out of a predetermined range by performing various filter processes on the imaging data. Then, the measurement area specifying function unit 12 specifies, as the measurement area, an area including pixels whose luminance values are out of a predetermined range in the imaging data. Note that the predetermined range can be changed and set as appropriate. Also, as the filtering process applied to the image data, for example, a well-known process such as a simple binarization process, a representative difference process, a straight line detection process, or the like can be employed.

  When the measurement region specifying function unit 12 specifies the measurement region based on the imaging data, the measurement region specifying function unit 12 generates coordinate data necessary for specifying the measurement region and outputs the coordinate data to the film state measurement function unit 13. Note that the coordinate data output by the measurement region specifying function unit 12 is position information for specifying a partial region of the glass substrate on the measurement stage 11b, that is, the measurement region. One corner may be set as the origin (0, 0), or one corner of the glass substrate may be set as the origin (0, 0).

The film state measurement function unit 13 is a function unit that measures the state of the alignment film formed in the measurement region specified by the measurement region specification function unit 12 by the film state measurement process. In this case, the film state measurement function unit 13 includes an ellipsometry unit 13a and a measurement position adjustment function unit 13b.
The ellipsometry unit 13a is an element that measures the state of the alignment film using a well-known ellipsometry principle. That is, the ellipsometry unit 13a irradiates the glass substrate on the measurement stage 11b, which is a sample, with the illuminator (not shown) and measures the polarization state of the reflected light with the measurement instrument (not shown). The ellipsometry unit 13a measures the state of the alignment film formed on the surface of the glass substrate based on the measured polarization state of the reflected light. In this case, the ellipsometry unit 13a can measure at least the thickness of the alignment film and the alignment direction as the state of the alignment film.

  The ellipsometry unit 13a measures the well-known “n value” and “k value”. The n value is a value indicating the refractive index of the sample. Based on this n value, the speed and direction of light passing through the glass substrate as the sample can be specified. The k value is a value indicating the extinction coefficient of the sample. Based on this k value, it can be specified how much energy of light passing through the glass substrate as the sample is absorbed.

  The measurement position adjustment function unit 13b moves the ellipsometry unit 13a in two directions, that is, a first adjustment direction along the longitudinal direction of the transfer function unit 11 and a second adjustment direction along a direction orthogonal to the longitudinal direction of the transfer function unit 11. It is a functional part for moving it mechanically. That is, the measurement position adjustment function unit 13b includes a drive mechanism (not shown) for moving the ellipsometry unit 13a in two directions. Thereby, the ellipsometry part 13a is comprised so that adjustment of the position is possible above the glass substrate mounted in the measurement stage 11b. Further, the ellipsometry unit 13a is configured to be movable in the vertical direction between the lowest position shown in FIG. 1 and the highest position shown in FIG. In this case, the ellipsometry unit 13a is in a state in which the measurement stage 11b is located on the upstream portion 10A side, that is, in a state where the measurement stage 11b is located on the downstream portion 10B side in the measurement region specifying process. That is, it moves to the uppermost position in the film state measurement process.

  Next, an example of the measurement operation performed by the state measurement apparatus 10 will be described with reference to the flowchart shown in FIG. Note that at the start of this measurement operation, the measurement stage 11b is located on the upstream portion 10A side as illustrated in FIG. As shown in FIG. 4, when the state measurement apparatus 10 starts this measurement operation, first, the state measurement device 10 executes a measurement region specifying process by the measurement region specifying function unit 12. That is, the state measurement apparatus 10 irradiates the entire surface of the glass substrate on the measurement stage 11b by the irradiation unit 12a (S1). And the state measuring apparatus 10 images the whole surface of the said glass substrate by the imaging part 12b in the state by which the glass substrate on the measurement stage 11b was irradiated by the irradiation part 12a (S2). Then, the state measuring device 10 determines whether or not there is a portion where the sign of the alignment film is inferior in the imaging data, specifically, the luminance value is out of the predetermined range in the imaging data. It is determined whether or not there is a location (S3). And the state measuring apparatus 10 transfers to step S4, when the indication that the state of the alignment film has deteriorated appears in the imaging data (S3: YES).

  When the state measurement device 10 proceeds to step S4, the state measurement device 10 specifies the measurement region based on the imaging data captured by the imaging unit 12b. Then, when the measurement region is specified by the measurement region specifying function unit 12, the state measurement apparatus 10 then illustrates the measurement stage 11b on which the glass substrate is placed by the transfer function unit 11 as illustrated in FIG. Then, it is transferred from the upstream part 10A mainly composed of the measurement region specifying function part 12 to the downstream part 10B mainly composed of the film state measuring function part 13 (S5). Thus, the measurement area specifying process by the measurement area specifying function unit 12 is completed.

  When the state measurement device 10 completes the measurement region specifying process, the state measurement apparatus 10 proceeds to the film state measurement process by the film state measurement function unit 13. That is, the state measuring apparatus 10 confirms the position of the measurement region on the glass substrate on the measurement stage 11b based on the coordinate data obtained by the measurement region specifying function unit 12 (S6). Then, the state measurement apparatus 10 moves the ellipsometry unit 13a over the confirmed measurement region (S7). And the state measuring apparatus 10 measures the state of the alignment film currently formed in the measurement area | region of the glass substrate by the ellipsometry part 13a (S8). In this case, the state measuring apparatus 10 measures at least the thickness and the alignment direction of the alignment film as the alignment film state by the ellipsometry unit 13a.

  Then, the state measuring apparatus 10 determines whether or not the state value of the alignment film obtained by the ellipsometry unit 13a, in this case, the film thickness value and the alignment direction value are within a predetermined allowable range (S9). The predetermined allowable range can be appropriately changed and set according to the size and shape of the glass substrate, the type of alignment film, and the like. If the state value of the alignment film is within the allowable range (S9: YES), the state measuring device 10 outputs OK determination information (S10). On the other hand, when the state value of the alignment film is out of the allowable range (S9: NO), the state measurement device 10 outputs NG determination information (S11). The OK determination information and the NG determination information may be output, for example, visually on a display monitor (not shown), audibly output from a speaker (not shown), or in other output modes. May be. Accordingly, the user can use the glass substrate on which the OK determination information is output for the subsequent manufacturing process, while providing the glass substrate on which the NG determination information is output for the inspection process or discarding it. be able to.

  Further, the state measuring device 10 may further include a sorting machine (not shown) and may be configured to automatically sort the glass substrate on which the OK determination information is output and the glass substrate on which the NG determination information is output. In step S3, the state measuring apparatus 10 proceeds to step S10 when there is no sign that the state of the alignment film is deteriorated in the imaging data (S3: NO).

  According to the state measurement apparatus 10 according to the present embodiment, the measurement operation of the state of the alignment film by the film state measurement function unit 13 is not performed over a wide region of the surface of the glass substrate on the measurement stage 11b. The measurement is performed only on a measurement region which is a part of the surface of the substrate and shows a sign that the state of the alignment film is deteriorated. As a result, it is possible to suppress the waste that the measurement operation is performed even on the region where the alignment film is in a good state, and efficiently measure the region where the state of the alignment film is deteriorated on the surface of the glass substrate. be able to.

  Moreover, according to the state measuring apparatus 10, the measurement region specifying function unit 12 responsible for the measurement region specifying process and the film state measuring function unit 13 responsible for the film state measuring process are integrally provided, and a glass substrate as a sample is provided. A transfer function unit 11 for transferring from the measurement region specifying function unit 12 to the film state measurement function unit 13 is provided. According to this configuration, a series of measurement operations including the measurement region specifying process and the film state measurement process can be continuously performed by the single state measurement apparatus 10. Therefore, a series of measurement operations can be smoothly performed as compared with a system that includes a device that performs measurement region specifying processing and a device that performs film state measurement processing separately.

  In addition, in a system that includes a device that performs measurement region specifying processing and a device that performs film state measurement processing separately, an operator must carry a sample between two devices or move between two devices. Therefore, the workload is large. On the other hand, according to the state measuring apparatus 10 according to the present embodiment, the operator can measure the state of the alignment film by using one state measuring apparatus 10 without carrying or moving the sample. Therefore, the workload can be reduced.

  Further, according to the state measuring device 10, the transfer function unit 11 moves the measurement stage 11 b on which the glass substrate is placed from the measurement region specifying function unit 12 after the measurement region is specified by the measurement region specifying function unit 12. Transfer to the film state measurement function unit 13. According to this configuration, it is possible to prevent the glass substrate from being transferred to the film state measurement function unit 13 without specifying the measurement region.

  Further, according to the state measuring apparatus 10, the measurement region specifying function unit 12 irradiates the entire surface of the glass substrate by the irradiation unit 12a, and images the entire surface of the glass substrate by the imaging unit 12b in that state. Thereby, it is possible to easily specify a region where an indication that the state of the alignment film is deteriorated appears over the entire surface of the glass substrate. Further, according to the state measurement device 10, the measurement region specifying function unit 12 specifies the measurement region based on the imaging data captured by the imaging unit 12b. Thus, by specifying the measurement region for the data, the specifying accuracy can be improved.

Further, according to the state measurement device 10, the measurement region specifying function unit 12 specifies a region where the value of the imaging data is outside the predetermined range as the measurement region. In this way, by clearly defining the reference for specifying the measurement region, the measurement region specifying accuracy can be further improved.
Further, according to the state measurement device 10, the imaging direction by the imaging unit 12 b can be adjusted by the imaging direction adjustment unit 14. According to this configuration, the surface of the glass substrate can be imaged in the imaging direction corresponding to the size and shape of the glass substrate, the type of alignment film, and the like.
Further, according to the state measuring apparatus 10, the film state measuring function unit 13 can measure the thickness of the alignment film and the alignment direction of the alignment film as the state of the alignment film by the ellipsometry unit 13a. According to this configuration, the state of the alignment film can be measured with high accuracy.

  Note that the present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the gist thereof. For example, the size and shape of the measurement stage 11b can be appropriately changed according to the size and shape of the glass substrate to be measured, the type of alignment film, and the like. In this case, the transfer speed of the measurement stage 11b may be appropriately adjusted according to the size and shape of the measurement stage 11b.

  In the drawings, 10 is a liquid crystal alignment film state measuring device, 11 is a transfer function unit, 12 is a measurement region specifying function unit, 12a is an irradiation unit, 12b is an imaging unit, 13 is a film state measurement function unit, and 14 is an imaging direction adjustment. , 100 is a liquid crystal panel, 101 and 102 are glass substrates, and 104 is an alignment film.

Claims (4)

An apparatus for measuring the state of an alignment film formed on the surface of a glass substrate constituting a liquid crystal panel,
A measurement region specifying function unit that specifies a region where a sign that the state of the alignment film is deteriorated in the surface of the glass substrate appears as a measurement region,
A film state measuring function unit for measuring the state of the alignment film formed in the measurement region specified by the measurement region specifying function unit;
A transfer function unit for transferring the glass substrate from the measurement region specifying function unit to the film state measurement function unit;
With
The measurement region specifying function unit includes an irradiation unit that irradiates the entire surface of the glass substrate, and an imaging unit that images the entire surface of the glass substrate while being irradiated by the irradiation unit, and is imaged by the imaging unit. The measurement region is specified based on the captured image data, and a pair of leg portions whose base end portions are rotatably attached to the transfer function portion and the distal end portions of the leg portions are connected to each other. An imaging direction adjusting unit in which the imaging unit is attached to the coupling unit, and the transfer function unit is configured to specify the measurement region. A state measuring apparatus for a liquid crystal alignment film in which a functional part and the film state measuring functional part are integrally connected.   The liquid crystal alignment according to claim 1, wherein the transfer function unit transfers the glass substrate from the measurement region specifying function unit to the film state measuring function unit after the measurement region is specified by the measurement region specifying function unit. Membrane state measuring device. The measurement region specifying function unit, the state measuring apparatus for a liquid crystal alignment film according to claim 1 or 2 values of the imaging data to identify a region that is outside the predetermined range as the measurement region. The film state measurement function unit, as a state of the alignment layer, the state measuring apparatus for a liquid crystal alignment film according to any one of claims 1 to 3 for measuring the orientation direction of the thickness and the alignment layer of the alignment layer .

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