JP4429759B2 - Manufacturing method of liquid crystal display panel - Google Patents

Description

  The present invention relates to a method for manufacturing a liquid crystal display panel suitable for making the density of spacers dispersed on a substrate uniform.

  In general, when manufacturing a liquid crystal panel, in order to keep two substrates at a constant interval, spacers made of plastic fine particles of about 3 to 5 μm are uniformly dispersed on one substrate, and then the other coated with a sealing material. It is bonded to the substrate.

  To disperse the spacers, a powdered spacer is accommodated, a tank that mixes the flowing air little by little, a pipe that guides the spacer mixed in the air from the tank to the outlet to the board, the outlet and the board A spacer spraying device provided with a spraying tank having a table for holding the container is used.

  In the spraying tank, the spacer is sprinkled from the blowout port installed above the stage holding the substrate and adheres to the surface of the substrate, and such a spacer spraying device is currently widely used. .

  When the spacers are dispersed, the problem is that the spacers condense. When a plurality of spacers are brought into close contact with each other, the portion becomes higher, so that a gap abnormality occurs when the substrates are bonded together.

  When a liquid crystal panel is assembled using a substrate in which such a gap abnormality is generated, the thickness of the liquid crystal in the gap abnormality portion (hereinafter referred to as a cell gap) becomes thicker than the other portions, and the electrical − The optical characteristics change, fading color, darkening, etc. occur.

  As a means for preventing the spacers from condensing, it is known to use the repulsive force between the same poles generated by static electricity, and this repulsive force is mixed with the spacer, so that the spacer and air, the spacers, It is thought to occur due to a collision between the spacer and the inner wall of the pipe.

  In addition, an invention has been made in which charging is performed by locally generating an electric field by providing a charging device in the spacer spraying device (see, for example, Patent Document 1 or Patent Document 2).

  However, in the above prior art, static electricity is effective in preventing the spacers from condensing, but it affects the density of the spacers, resulting in a dynamic change in charge amount or non-uniformity. It has been found to cause problems.

  This is caused by a change in the potential of the surface of the substrate caused by the amount of the charged spacer adhering to the substrate, or a change in the amount of the spacer after being ejected from the outlet. It is thought that this affects the charged spacer.

The conventional liquid crystal display panel manufacturing method or manufacturing apparatus does not have a function to directly and uniformly control the charge amount of the spacer. It is considered that a phenomenon such as an unstable spray density generated when changing a parameter occurs due to the influence of the charging of the spacer and the dynamic change of the charging on the moving line.
JP-A-5-66407 Japanese Patent Laid-Open No. 5-158049

  In the present invention, by controlling the charge amount of the spacer used in the liquid crystal display panel to be constant, it is possible to make the dispersion density of the spacer uniform and to manufacture a liquid crystal display panel with stable display characteristics. To do.

  In general, the charging of the spacer often occurs mainly in a pipe connecting a tank in which the spacer is mixed little by little to the air and the spray nozzle to the substrate. Therefore, the potential of the pipe is set to a certain level (non-zero). ), It is possible to control the charge of the spacers generated in the piping at the time of collision, to make the dispersion density of the spacers uniform, and to make the display characteristics of the liquid crystal display panel uniform. .

  In that case, in order to be able to sufficiently collide with the pipe even if the spacer is charged, it is necessary to make the pipe shape into a loop shape, a spiral shape, a waveform, etc. If the length is not increased to some extent, the number of collisions decreases and good results cannot be obtained.

  Further, in order to control the potential in the pipe, unless it depends on an external electric circuit, it changes depending on the charge transfer from the spacer.

  Furthermore, it is desirable to control the potential of the location of the pipe for applying the potential, near the spray nozzle of the spacer, or including the spray nozzle itself. In addition to being charged when the spacer collides with air or other spacers or the inner wall of the pipe, it is possible to charge by discharging from an electrode to which a high voltage is applied, but in this case, the charge varies greatly. The discharge charging must be performed before the potential control.

  Therefore, in the method for manufacturing a liquid crystal display panel according to the present invention, the method for manufacturing a liquid crystal display panel includes a step of manufacturing a liquid crystal display panel having a structure in which two substrates are bonded together via a spacer and a sealant. In a state where air is mixed with a fine particle spacer, it is fed into a pipe to which a constant potential is applied from the potential control unit, and the spacer to which a constant potential is applied by colliding with the inner wall of the pipe Basically, it includes a step of spraying into a spray tank from a spray nozzle coupled to the tip of the pipe and adhering to the substrate on the substrate holder.

  In the method of manufacturing a liquid crystal display panel according to the present invention, it is possible to control the spacer distribution density on the substrate to be uniform by simply and easily controlling the charge amount of the spacer alone. Therefore, according to the present invention, a liquid crystal display panel having uniform display characteristics can be manufactured.

  FIG. 1 is an explanatory view showing a main part in a manufacturing apparatus of a liquid crystal display panel used for carrying out the present invention. In the figure, 1 is a spacer stock part, 2 is a rotary quantitative scooping drum, 3 is a dry air feed pipe, 4 is a spacer spray nozzle, 5 is a pipe connecting the spacer stock portion 1 and the spacer spray nozzle 4, 5A is a spiral conductive pipe formed at a suitable position of the pipe 5, 6 Is a spacer spraying tank, 7 is a substrate holder, 8 is an exhaust port, 9 is an open / close gate, 10 is a robot arm for carrying in a substrate, 11 is a robot arm for carrying out a substrate, 12 is a stage for spacer counting, 13 is a personal computer for control, 14 Denotes a potential control unit, 15 denotes a spacer count image processing unit, and 16 denotes a camera.

  The above-described liquid crystal panel manufacturing apparatus includes a spacer stock unit 1, a spacer constant scooping drum 2, a spacer mixing unit including a dry air feed pipe 3, a spray nozzle 4, a spray tank 5, and a spray mechanism including a substrate holder 7. A pipe unit comprising a pipe 5 having a spiral conductive pipe 5A connected to the potential controller 14 by coupling the spacer mixing part and the spreading mechanism, an image processing unit for measuring the density of spacers scattered on the substrate, and It is composed of four elements of a personal computer unit comprising a control personal computer 13 for managing data.

  (1) The substrate flowing from the previous process is loaded into the spacer spray tank 6 from the open / close gate 9 by the substrate loading robot arm 10 and then placed on the substrate holder 7.

  (2) The spacer stocked in the spacer stock section 1 is quantified by the quantitative scooping drum 2 and sucked into the pipe 5 of the piping section by the compressed air supplied from the dry air feed pipe 3. It is.

  (3) The sucked spacer is uniformly charged by colliding with the inner wall of the pipe whose electric potential is controlled, in particular, the spiral conductive pipe 5A, and enters the spray tank 5 through the spray nozzle 4 in the spray mechanism. It is scattered.

  (4) When the spacers dispersed in the spraying tank 5 are settled, the distribution is made uniform due to the repulsive force caused by the charging and adheres to the substrate.

  (5) The substrate to which the spacer is attached is taken out of the spray tank 5 by the substrate carrying robot arm 11 and then placed on the spacer counting stage 12, where a certain range of the substrate is photographed by the camera 16. After performing the measurement including doing, it flows out to the subsequent process.

  (6) The measured spacer density is processed by the management personal computer 13 and fed back to the potential control unit 14 as necessary to control the potential so that the spacer distribution density becomes constant.

It is explanatory drawing showing the principal part in the manufacturing apparatus of the liquid crystal display panel used for implementing this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spacer stock part 2 Fixed pick-up drum 3 Dry air inflow pipe 4 Spacer spray nozzle 5 Piping 5A Spiral conductive pipe formed in an appropriate position of pipe 5 Spacer spray tank 7 Substrate holder 8 Exhaust port 9 Opening / closing gate 10 Substrate Robot arm for loading 11 Robot arm for unloading substrate 12 Spacer counting stage 13 PC for control 14 Potential control unit 15 Image processing unit for spacer counting 16 Camera

Claims (2)

In a manufacturing method of a liquid crystal display panel including a step of manufacturing a liquid crystal display panel having a configuration in which two substrates are bonded together via a spacer and a sealing material,
From a conductive material that is arranged in the vicinity of the potential control unit and is given a constant potential from the potential control unit by deforming the spacer selected from the spiral, wavy, and spiral shapes into a shape that easily collides. In a state where fine particle spacers are mixed with air,
Substrate on spraying to a substrate holder in spraying tank spacers which the constant potential to collide with the inner wall of the pipe that is the deformation is given from the spray nozzle coupled to the distal end of the pipe connecting to the pipe that is the deformed The manufacturing method of the liquid crystal display panel characterized by including the process made to adhere to.   2. The method of manufacturing a liquid crystal display panel according to claim 1, wherein the spacer is made of at least a surface made of an insulating plastic.

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