JP4520224B2 - Method and apparatus for applying sealant to liquid crystal panel - Google Patents

Description

  The present invention relates to a liquid crystal panel, and more particularly to a sealing agent coating method and apparatus for sealing two substrates constituting the liquid crystal panel.

  Various types of liquid crystal display devices have been put into practical use. Currently, active matrix liquid crystal display devices, which are the mainstream, include a thin film transistor substrate (TFT substrate) on which a pixel selection circuit is formed and a color filter of multiple colors. A liquid crystal layer is sandwiched between color filter substrates (CF substrates) on which are formed. The TFT substrate has a pixel region (display region) that occupies most of the area, and a drive circuit region and other circuit regions arranged outside the pixel region.

  In the pixel area, normally, one color pixel (pixel) composed of sub-pixels (sub-pixels) of three colors (red: R, green: G, blue: B) is arranged in a matrix. Each subpixel is composed of a thin film transistor circuit (pixel circuit). On the other hand, on the CF substrate, color filters of red: R, green: G, and blue: B, which are arranged to face each of the sub-pixels of the three colors that constitute the pixel region of the TFT substrate, are formed. .

  On the CF substrate, a light-shielding film (black matrix) and color filters for each color are formed to prevent light color between the filters adjacent to the main surface of the transparent insulating substrate, preferably made of glass, to improve color purity and contrast. Is done. Thereafter, a protective film (also referred to as a planarization film or an overcoat film) made of an organic material is formed on the surface. In the so-called IPS type, an alignment film is formed directly on the protective film. In the TN type, a transparent electrode such as ITO is formed on the protective film.

 A liquid crystal panel is formed by laminating two substrates on which various functional films including such electrodes or color filters are formed and enclosing liquid crystal in a bonding gap. The two substrates are bonded together by applying a sealant around the outside of the pixel region of one substrate (for example, TFT substrate) and applying the other substrate (for example, CF substrate) to a predetermined positional relationship. Then, the sealant is cured and sealed. In general, when applying the sealing agent, a discontinuous portion for injecting liquid crystal is provided in a part of the sealing agent ridge that is circulated and used as a liquid crystal injection port. However, in the case of adopting so-called potting (liquid crystal dropping method), in principle, it is not necessary to provide discontinuous portions in the sealing agent. Application of such a sealing agent to the substrate is automatically performed by a dispenser. A laser displacement meter having a spot light source is used for coating dimensions including the coating width, coating height, and coating position.

  FIG. 8 is an explanatory diagram of measurement waveforms when the cross section of the sealing agent applied to the substrate and the dimensions thereof are measured using a laser displacement meter. FIG. 8A is a cross-sectional view of the sealing agent SL applied in a bowl shape on the surface of the substrate SUB, and FIG. 8B is a laser displacement of the sealing agent in FIG. 8A. It is a figure which shows a measurement waveform when it measures with a meter. In general, the cross-sectional shape in the direction intersecting with the wrinkles of the applied sealing agent SL is substantially convex as shown in FIG.

  When measuring the dimension of the sealant SL using a laser displacement meter, the laser displacement meter is moved so that the spot light of the laser is in a direction intersecting with the edge of the sealant SL. Then, a change in the amount of laser light reflected from the substrate surface and the applied sealant is acquired as a waveform electrical signal as shown in FIG. 8B, and is measured using the waveform of the signal.

There are many patent documents concerning the application of this type of sealant. As for the measurement of the width dimension of the applied sealant, there is a patent document that measures the width of the sealant applied to the substrate by a scale formed on the substrate. 1 is disclosed.
JP-A-8-106100

  With respect to the application size of the sealant using the laser displacement meter, the application height H of the sealant applied from the waveform SIG in FIG. 8B can be accurately measured. However, the measurement signal of the laser displacement meter is the boundary between the substrate surface and the sealing agent, that is, the rising and falling positions of the sealing agent, and the waveform SIG has spreads ΔD1 and ΔD2 as shown in FIG. It is difficult to accurately measure the coating width W of the agent. Variations in the height and width of the sealant application dimensions may be due to excess or insufficient sealant and application deviation from the specified position. When the substrates are bonded together, the sealant may enter the pixel area, It also causes deterioration of display quality due to dripping of the sealing agent at the edge or non-uniformity of the cell gap (gap between the two substrates) of the liquid crystal panel.

  An object of the present invention is to provide a measuring method and an apparatus for applying a sealing agent at a predetermined position with an accurate application amount by accurately measuring the height and width of the sealing agent application dimension. .

The method for applying a sealant to a liquid crystal panel according to the present invention comprises a sealant application device having an application part and an application control part. It is a method for integrating. That is,
An image pickup device and a laser displacement meter are provided in the longitudinal direction of the sealant applied in a bowl shape,
Measure the application height of the applied bowl-shaped sealant by the laser displacement meter,
Measure the application width and application position on the substrate of the coating-like sealant applied by the imaging device,
Calculate application amount data of the applied sealant from the measured application height data and application width data,
Calculate the deviation data of the application position by the calculated application position,
The sealant application amount data and the application position shift amount data obtained by the calculation are fed back to the application controller of the sealant application device, and a predetermined amount of sealant is continuously applied to a predetermined position on the substrate. And is applied.

In addition, the liquid crystal panel sealant application device according to the present invention is an apparatus for bonding the other substrate to one substrate on which the sealant is applied in a bowl shape and integrating the other substrate as a liquid crystal panel. That is,
The sealant application device includes a sealant application system having an application part and an application control part;
A laser displacement meter and an imaging device arranged in the longitudinal direction of the bowl-shaped sealant applied to the substrate, and a measurement output signal of the laser displacement meter are processed to calculate the application height data of the bowl-shaped sealant. Displacement calculation unit, processing the imaging output signal of the imaging device to calculate the application width data of the bowl-shaped sealant and the application position data on the substrate, and the deviation amount between the application amount of the sealant and the application position An application sealant inspection system having an inspection control unit that generates data and feeds back the generated application amount data of the sealant and application position shift amount data to the application control unit of the sealant application system. And

  The inspection control unit generates the coating amount data by multiplying the coating height measured by the laser displacement meter × the coating width measured by the imaging device by a predetermined coefficient. The imaging device is preferably a CCD camera.

 When measuring the application height of the applied saddle-shaped sealant by the laser displacement meter, the rising area and falling area signals of the applied saddle-shaped sealant are masked.

  The present invention is not limited to the above-described configuration and the configuration described in the embodiments described later, and it goes without saying that various modifications can be made without departing from the technical idea of the present invention.

  With the method and apparatus for applying the sealant of the liquid crystal panel of the present invention, the rising portion (one application boundary between the substrate and the sealant) and the falling portion (the other application boundary between the substrate and the sealant) can be accurately measured. Thus, deviation data between the application width data and the reference position can be obtained with high accuracy. The application amount data can be accurately obtained from the application width data and application height data. By feeding back these data to the control unit of the seal application system, it becomes possible to accurately apply a seal agent of a predetermined width to a predetermined position, and uneven application of the seal agent (variation in width, position, and height). ) Can be reduced.

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

  FIG. 1 is a diagram illustrating the overall configuration of the sealing agent application apparatus of the present invention. This sealant application device is composed of a sealant application system (indicated as an application system in FIG. 1) and an application sealant inspection system (indicated as an inspection system in FIG. 1). The sealant application system includes a nozzle that discharges the sealant SL onto the surface of the substrate SUB of the liquid crystal panel, an application unit PLT having a sealant supply mechanism, and an application control unit CTL-A that controls the application unit PLT.

  Further, the coating sealant inspection system includes a laser displacement meter LDM arranged in the longitudinal direction of the bowl-shaped sealant SL applied to the substrate SUB, a CCD camera CAM as an imaging device, and a measurement output signal of the laser displacement meter LDM. Displacement calculation unit DMC for calculating application height data of cocoon-shaped sealing agent SL applied by processing, and imaging output signal of the imaging device to process application width data of cocoon-like sealing agent and on the substrate The image processing unit IPR that calculates application position data is used to generate application amount data and application position deviation data of the sealant SL applied on the substrate SUB, and the generated application amount of the sealant An inspection control unit CTL-I that feeds back data and application position deviation amount data to the application control unit CTL-A of the sealant application system is provided.

  FIG. 2 is an explanatory diagram of an arrangement example of the laser displacement meter LDM and the CCD camera CAM shown in FIG. As shown in FIG. 1, a laser displacement meter LDM and a CCD camera CAM are arranged immediately above the bowl-shaped sealant SL applied to the substrate SUB. Reference symbol FLD indicates the field of view of the CCD camera CAM, and reference symbol SGT indicates the measurement region of the laser displacement meter LDM. In this example, the application width of the sealant SL is 200 μm to 400 μm, and the arrangement interval between the laser displacement meter LDM and the CCD camera CAM is 70 mm, but this is only an example. C-C 'indicates a reference position where the sealant SL is applied.

  FIG. 3 is an explanatory diagram of an image captured by the CCD camera CAM. The image picked up by the CCD camera CAM calculates the coating width W of the sealant SL by contour enhancement such as differentiation processing or digital data processing by the image processing unit IPR of the inspection control unit CTL-I in FIG. At the same time, the amount of positional deviation from the center C-C ′ of the predetermined application position is calculated.

  FIG. 4 is an explanatory diagram of an output signal of the laser displacement meter LDM. As described with reference to FIG. 8B, the signal SIG measured by the laser displacement meter LDM has a rising portion (one application boundary between the substrate and the sealing agent) and a falling portion (the other of the substrate and the sealing agent). It is difficult to accurately measure the coating width W of the sealant because it has spread ΔD1 and ΔD2 on the coating boundary. Therefore, in this embodiment, the signal H at the rising edge and the falling edge is masked to obtain the height H of the signal SIG without being affected by the waveforms at the rising edge and the falling edge. In the figure, M-M ′ indicates the maximum height position of the masked signal SIG, and “0” indicates a reference level corresponding to the substrate surface.

  For signal masking, physical masks MSL and MKR may be provided in the laser scanning region, or a method of cutting the signals of the rising and falling portions in the signal processing stage may be employed.

FIG. 5 is an explanatory diagram of a control procedure of the sealant application device shown in FIG. First, a sealing agent is applied to the substrate (step 0, hereinafter referred to as S-0). The height of the applied sealant is measured with a laser displacement meter (S-1). Further, the application width and application position of the sealing agent are measured from the image pickup signal of the CCD camera (S-2). The amount of sealant applied is calculated from the measured height and width data of the sealant (S-3). The formula for calculating the coating amount is as follows. That is,
Application amount = height of sealant x width of sealant x predetermined coefficient
The predetermined coefficient is a unit length in the application direction of the sealant.

  Next, the amount of displacement from the reference position is calculated from the position data (S-4). Then, the sealant coating amount data calculated in (S-3) and the positional deviation amount data calculated in (S-4) are fed back to the coating system coating control unit CTL-A (S-5). The application control unit CTL-A adjusts the application amount and application position of the sealant in the application unit PLT based on the fed back application amount data and positional deviation amount data (S-6), and applies the sealant. It is applied to the substrate (S-7). Thereafter, by repeating this, it becomes possible to accurately apply a sealing agent having a predetermined width to a predetermined position on the substrate, and display caused by uneven application of the sealing agent (variation in width, position, and height). Defects can be reduced.

  FIG. 6 is a schematic cross-sectional view of a liquid crystal panel manufactured using the sealing agent coating method and apparatus of the present invention. FIG. 7 is a schematic plan view of a thin film transistor substrate of a liquid crystal panel manufactured using the sealing agent coating method and apparatus of the present invention. As shown in FIG. 6, the liquid crystal panel PNL is integrated by bonding the thin film transistor substrate SUB1 and the color filter substrate SUB2 with a sealant SL. A thin film transistor TFT constituting a pixel is formed on the inner surface of the thin film transistor substrate SUB1. On the other hand, a color filter CF is formed on the inner surface of the color filter substrate SUB2 corresponding to each pixel. Further, a scanning line driving circuit chip GD and a signal line driving circuit chip DD (see FIG. 7) are mounted on the end portion of the thin film transistor substrate SUB1 that is not covered with the color filter substrate SUB2. Reference numeral LC denotes a liquid crystal layer.

  As shown in FIG. 7, the thin film transistor substrate SUB1 includes thin film transistors at intersections between the scanning lines GL driven by the scanning line driving circuit chip GD and the signal lines DL driven by the signal line driving circuit chip DD. Many pixels PX are arranged in a matrix. A sealant Sl is applied around the outside of the pixel regions arranged in a matrix, and the color filter substrate SUB is bonded and fixed thereon.

  The present invention is not limited to the liquid crystal panel described above, and can be applied to sealing of other types of liquid crystal panels, flat panel display devices similar to the liquid crystal panels, and other similar electronic devices.

It is a figure explaining the whole structure of the sealing agent application | coating apparatus of this invention. It is explanatory drawing of the example of arrangement | positioning of the laser displacement meter LDM and CCD camera CAM shown in FIG. It is explanatory drawing of the image which CCD camera CAM imaged. It is explanatory drawing of the output signal of a laser displacement meter LDM. FIG. 2 is an explanatory diagram of a control procedure of the sealant application device shown in FIG. It is a schematic cross section of the liquid crystal panel produced using the sealing agent application | coating method and apparatus of this invention. It is a schematic plan view of the thin-film transistor substrate of the liquid crystal panel produced using the sealing agent application | coating method and apparatus of this invention. It is explanatory drawing of a measurement waveform when the cross section of the sealing agent apply | coated to the board | substrate and its dimension are measured using a laser displacement meter.

Explanation of symbols

SUB ... Liquid crystal panel substrate, SL ... Sealing agent, PLT ... Application unit, CTL-A ... Application control unit, LDM ... Laser displacement meter, CAM ... -Imaging device (CCD camera), DMC ... Displacement calculation unit, IPR image processing unit, CTL-A ... Application control unit, CTL-I ... Inspection control unit.

Claims (6)

Sealing agent coating method for liquid crystal panel for laminating one substrate to one substrate coated with the sealing agent in a bowl shape using a sealing agent coating apparatus having a coating unit and a coating control unit and integrating them as a liquid crystal panel Because
An image pickup device and a laser displacement meter are provided in the longitudinal direction of the sealant applied in a bowl shape,
Measure the application height of the applied bowl-shaped sealant by the laser displacement meter,
Measure the application width and application position on the substrate of the coating-like sealant applied by the imaging device,
Calculate application amount data of the applied sealant from the measured application height data and application width data,
Calculate the deviation data of the application position by the calculated application position,
The sealant application amount data and the application position shift amount data obtained by the calculation are fed back to the application controller of the sealant application device, and a predetermined amount of sealant is continuously applied to a predetermined position on the substrate. And applying the sealing agent for a liquid crystal panel.   2. The signal of the rising area and the falling area of the applied saddle-shaped sealant is masked when the application height of the applied saddle-shaped sealant is measured by the laser displacement meter. The sealing agent application | coating method of liquid crystal panel of description. 2. The liquid crystal panel according to claim 1, wherein the calculation of the coating amount data is obtained by multiplying the coating height measured by a laser displacement meter × the coating width measured by the imaging device by a predetermined coefficient. The sealing agent application method. A sealant coating device for a liquid crystal panel for laminating one substrate to one substrate coated with a sealant in a bowl shape and integrating it as a liquid crystal panel,
The sealant application device includes a sealant application system having an application part and an application control part;
A laser displacement meter and an imaging device arranged in the longitudinal direction of the bowl-shaped sealant applied to the substrate, and a measurement output signal of the laser displacement meter are processed to calculate the application height data of the bowl-shaped sealant. Displacement calculation unit, processing the imaging output signal of the imaging device to calculate the application width data of the bowl-shaped sealant and the application position data on the substrate, and the deviation amount between the application amount of the sealant and the application position An application sealant inspection system having an inspection control unit that generates data and feeds back the generated application amount data of the sealant and application position shift amount data to the application control unit of the sealant application system. Liquid crystal panel sealant coating device.   The said inspection control part multiplies the coating width measured by the said coating height measured by the laser displacement meter x the said imaging device by a predetermined coefficient, and produces | generates the said coating amount data, It is characterized by the above-mentioned. Liquid crystal panel sealant coating device. The liquid crystal panel sealant coating apparatus according to claim 4, wherein the imaging device is a CCD camera.

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