JP2005070605A - Manufacturing method and inspecting apparatus for liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal panel from a laminated liquid crystal substrate formed by laminating two substrates together across a liquid crystal layer and an inspecting apparatus for inspecting the laminated liquid crystal substrate. <P>SOLUTION: The apparatus which inspect the laminated liquid crystal substrate 1 formed by laminating the two substrates across the liquid crystal layer has a couple of substrates 11 and 21 arranged on both the outer sides of the laminated liquid crystal substrate 1, electrodes 12 and 22 formed on the couple of substrates 11 and 21, respectively, dielectric resin layers 13 and 23 coating the electrodes 12 and 22, and a power source 30 which applies a voltage to the electrode 12 and 22. Consequently, when the voltage is applied to the electrodes 12 and 22, charges are generated on surfaces of the dielectric resin layers 13 and 23, so an electric field is produced in a normal direction of a surface of the laminated liquid crystal substrate 1. Liquid crystal molecules in an alignment-defective area can not sufficiently be aligned. Therefore, the stuck liquid crystal substrate 1 is placed in an illumination state and then an alignment defect which can be confirmed through the illumination can easily be found. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a liquid crystal panel from a bonded liquid crystal substrate in which two substrates are bonded via a liquid crystal layer. The present invention also relates to an inspection apparatus for inspecting a bonded liquid crystal substrate.

  As an inspection method for finding defects in the liquid crystal panel, for example, an inspection method disclosed in Patent Document 1 can be cited. In the inspection method of Patent Document 1, an electrode substrate is disposed outside a common substrate or a segment substrate of a liquid crystal display device, and a voltage is applied between the electrode of the electrode substrate and the common electrode or the segment electrode. The segment electrodes are electrically connected. According to this inspection method, a fine disconnection defective pixel that is extremely difficult to find by a conventional visual method can be clarified by lighting or non-lighting of the liquid crystal display.

  On the other hand, as a method of filling a liquid crystal material in the liquid crystal panel, a dip type or a dispenser type can be mentioned. In these methods, a bonded mother substrate (also referred to as a multi-planar substrate) is divided into individual panels, and then a liquid crystal material is filled from the opening of the sealing material, and the opening is further sealed. After the assembly of the liquid crystal panel is completed in this way, the liquid crystal panel is inspected. However, in the dip type or dispenser type filling method, the larger the liquid crystal panel, the longer the time required for filling the liquid crystal. Also, it usually takes at least a few days from the time the board is put into the assembly process of the liquid crystal panel until the inspection is completed. If a problem occurs in the assembly process of the liquid crystal panel, the discovery is delayed and a large amount of There is a risk that a defective panel will be assembled.

  Therefore, in recent years, a one-drop filling method (hereinafter also referred to as a drop bonding method) has been developed as a method of filling a liquid crystal material in a liquid crystal panel. The one-drop filling method is a method in which a liquid crystal material is dropped into a seal pattern frame of one substrate before overlapping without providing an opening in the seal pattern, and a pair of substrates are stacked and attached under reduced pressure. According to this one-drop filling method, there is an advantage that the screen size can be increased. In addition, since the liquid crystal panel can be inspected before multi-sided processing, if a defective liquid crystal panel is found, wasteful work on the defective panel can be reduced and early feedback to the previous process can be achieved. It becomes possible.

  For example, Patent Document 2 discloses a method for inspecting lighting of a plurality of liquid crystal display panels formed on a bonded liquid crystal substrate before dividing the dropped bonded liquid crystal substrate by a single drop filling method. Specifically, in Patent Document 2, before cutting an unnecessary portion (stained portion) of a substrate, an electrode terminal provided in the scraped portion is exposed, and a voltage is applied to the exposed electrode terminal to provide a liquid crystal. It is disclosed that an image defect inspection is performed by lighting a display panel.

JP 4-191672 A

JP 2000-66162 A

  However, the inspection method disclosed in Patent Document 1 can inspect only a liquid crystal panel having a simple matrix structure and cannot be applied to a liquid crystal panel having an active matrix structure.

  In the method of Patent Document 2, it is necessary to form an inspection pattern on a substrate, so that the panel removal efficiency is lowered. In addition, lighting may not be possible due to disconnection or leakage of the inspection pattern.

  The method of the present invention includes a step of inspecting a bonded liquid crystal substrate in which two substrates are bonded via a liquid crystal layer, and a method of manufacturing a liquid crystal panel from the bonded liquid crystal substrate, wherein the inspection step Arranging a pair of electrodes each covered with a dielectric layer on both outer sides of the bonded liquid crystal substrate, applying a voltage to the pair of electrodes, and making light incident on the bonded liquid crystal substrate Including the step of

  The apparatus of the present invention is an apparatus for inspecting a bonded liquid crystal substrate in which two substrates are bonded via a liquid crystal layer, and a pair of substrates disposed on both outer sides of the bonded liquid crystal substrate; Electrodes formed on a pair of substrates, a dielectric layer covering the electrodes, and a power source for applying a voltage to the electrodes.

  Each of the pair of substrates may include an elastic member that is formed on the periphery of the dielectric layer and has an opening in plan view. The liquid crystal panel may be a liquid crystal display panel that displays characters, images, and the like on the panel surface.

  According to the present invention, a lighting inspection is performed without dividing a bonded liquid crystal substrate formed by a drop bonding method and without using an inspection terminal, and an alignment defect that can be confirmed by lighting is easily obtained. And it can be discovered early. The present invention can be applied not only to a liquid crystal panel having a simple matrix structure but also to all liquid crystal panels using the electro-optic effect. In this specification, the term “electro-optic effect” means that the liquid crystal molecules in the liquid crystal layer are affected by an electric field by applying a voltage to a pair of electrodes sandwiching the liquid crystal layer, and the transmittance of the liquid crystal layer is increased. It means changing.

  Further, by making the distance between the substrate of the inspection apparatus and the drop-bonded liquid crystal substrate uniform in the entire plane, a plurality of liquid crystal panels formed on the drop-bonded liquid crystal substrate can be lighted uniformly. Accordingly, the liquid crystal panel with poor alignment can be rejected (excluded) without going through the steps of strip division, single-piece division, and lighting inspection, so that early feedback to the previous process and wasteful work can be reduced.

  According to the present invention, a voltage is applied to the external electrodes disposed on both outer sides of the bonded liquid crystal substrate, and an electric field is generated in the normal direction of the liquid crystal panel surface. The panel can be turned on for inspection. Therefore, since no inspection pattern is required, there is no reduction in panel removal efficiency, and there is no possibility that lighting will not be possible due to disconnection or leakage of the inspection pattern. Further, since direct electrical connection with the liquid crystal panel is not performed, the present invention can be applied not only to a simple matrix type but also to an active matrix type liquid crystal panel in general.

  Embodiments according to the present invention will be described below with reference to the drawings. In the following embodiments, an active matrix drive type liquid crystal panel will be described as an example of the liquid crystal panel. However, the liquid crystal panel may be a simple matrix drive type as well as an active matrix drive type.

  The liquid crystal panel according to the present invention can be used not only as a liquid crystal display element but also as an image shift element for sequentially shifting pixels optically and a parallax barrier element capable of displaying a three-dimensional image. The image shift element has at least one combination of a liquid crystal panel that modulates the polarization state of light and a birefringence element that shifts the optical path according to the polarization state of the light emitted from the liquid crystal panel. Further, the parallax barrier element can display a stereoscopic image by being combined with an image display element having a left-eye pixel and a right-eye pixel.

  First, a bonded liquid crystal substrate to be inspected in the present embodiment will be described with reference to FIGS. 1 is a plan view schematically showing a bonded liquid crystal substrate, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. A bonded liquid crystal substrate 1 shown in FIGS. 1 and 2 is a multi-sided substrate in which four liquid crystal panels are multi-sided. Hereinafter, the liquid crystal panel formed on the bonded liquid crystal substrate 1 and before being divided is referred to as a liquid crystal panel 1.

  The liquid crystal panel 1 includes a pair of glass substrates 2 and 3 and a liquid crystal layer 5 sandwiched between the glass substrates 2 and 3 and the peripheral sealing material 4. One glass substrate 2 is a color filter substrate, and includes a color filter layer, a transparent electrode made of ITO (indium tin oxide) and the like, and a liquid crystal alignment film (not shown) made of polyimide and rubbed. Have.

  The other glass substrate 3 is a TFT (Thin Film Transistor) substrate, each of which includes a plurality of gate bus lines extending in the row direction, a plurality of source bus lines extending across the gate bus lines, a gate bus line and a source. A TFT provided near the intersection of the bus lines, a pixel electrode connected to the source bus line via the TFT and arranged in a matrix, and a liquid crystal alignment film (both not shown) covering the pixel electrode are included. On the other glass substrate 3, terminals 6 for inputting signals to the gate bus line and the source bus line are formed. Both glass substrates 2 and 3 can be formed by known methods such as a photolithography method and a printing method, respectively. The liquid crystal alignment films on both glass substrates 2 and 3 are rubbed so that the alignment directions are orthogonal to each other.

  A process for forming the liquid crystal layer 5 between the glass substrates 2 and 3 will be described. A peripheral sealing material 4 made of an epoxy resin or the like is formed on the surface of one of the glass substrates 2 and 3 by a screen printing method or a dispenser method. The pattern of the peripheral sealing material 4 does not have an opening serving as a liquid crystal injection port, and has a closed loop shape. After dropping a nematic liquid crystal material having a positive dielectric anisotropy into the pattern frame of the peripheral sealing material 4, both glass substrates 2 and 3 are superposed in a vacuum chamber. After taking out both the glass substrates 2 and 3 from a vacuum chamber, the periphery sealing material 4 is hardened and both glass substrates 2 and 3 are affixed. As a result, the liquid crystal layer 5 is sealed in each liquid crystal panel before multi-paneling.

(Embodiment 1)
FIG. 3 is a cross-sectional view schematically showing the inspection apparatus according to the first embodiment. The inspection apparatus according to the present embodiment includes an upper substrate 10 and a lower substrate 20 disposed to face the upper substrate 10. The upper substrate 10 and the lower substrate 20 are respectively glass substrates 11 and 21, transparent electrodes 12 and 22 formed on one surface of the glass substrates 11 and 21, and a transparent dielectric resin layer 13 covering the transparent electrodes 12 and 22. , 23 and polarizing plates 14, 24.

  As the glass substrates 11 and 21, those used in a general liquid crystal panel can be used. Specifically, transparent plate glass such as soda lime glass, borosilicate glass, aluminosilicate glass, and quartz glass can be used.

The transparent electrodes 12 and 22 are common electrodes (planar electrodes) formed on substantially the entire one surface of the glass substrates 11 and 21. As the transparent electrodes 12 and 22, those used in a general liquid crystal panel can be used. For example, a conductive metal oxide thin film such as ITO, SnO ₂ , ZnO, IZO (indium zinc oxide), or GZO (gallium zinc oxide) can be used. These metal oxide thin films can be formed by a known method such as an EB (electron beam) vapor deposition method, a sputtering film forming method, or a sol-gel method. In addition, you may use the glass substrate with a transparent electrode in which the transparent electrode was formed previously.

  The transparent dielectric resin layers 13 and 23 serve to prevent discharge from the transparent electrodes 12 and 22 and generate charges on the surface to align the liquid crystal molecules in the liquid crystal layer 3. The material of the transparent dielectric resin layers 13 and 23 may be a resin having translucency and electrical insulation, but TAC (triacetylcellulose) excellent in hygroscopicity, strength, transparency and optical characteristics. ) Is preferably used. The film thickness of the transparent dielectric resin layers 13 and 23 is about 100 μm to 500 μm. The transparent dielectric resin layers 13 and 23 can be formed by applying a transparent resin material to the entire surface of the glass substrates 11 and 21 by coating or the like and curing them.

  The polarizing plates 14 and 24 are arranged so that their polarization axes (transmission axes) are orthogonal to each other (so-called crossed Nicols arrangement). As the polarizing plates 14 and 24, a polarizing film obtained by adsorbing or dyeing a dichroic dye such as iodine or a dye on a PVA (polyvinyl alcohol) film and uniaxially stretching with high precision can be used.

  The transparent electrodes 12 and 22 are connected to a DC power supply 30 via lines 15 and 25, respectively. The DC power supply 30 is preferably one that can apply a voltage that can control the axial direction of liquid crystal molecules between the transparent electrodes 12 and 22. In place of the DC power source 30, an AC power source can be used.

  A light source 40 such as a backlight is disposed below the lower substrate 20. Since the upper substrate 10 and the lower substrate 20 have translucency, the light from the light source 40 can pass through both the substrates 10 and 20. When the reflective liquid crystal panel is inspected for lighting, the light source 40 is disposed on the observer side (upper side).

  FIG. 4 is a schematic cross-sectional view for explaining the operation of the inspection apparatus of the present embodiment. The inspection process of the bonded liquid crystal substrate will be described with reference to FIG. In FIG. 4, the liquid crystal panel 1 shown in FIGS. 1 and 2 is shown in a simplified manner.

  After arranging a pair of substrates 10 and 20 on both outer sides of the bonded liquid crystal substrate 1, both surfaces 1 a and 1 b of the bonded liquid crystal substrate 1 are sandwiched between the substrates 10 and 20. When a voltage is applied to the transparent electrodes 12 and 22 by the DC power supply 30, positive or negative charges are generated on the surfaces of the transparent dielectric resin layers 13 and 23, so that an electric field is generated in the normal direction of the liquid crystal panel 1. Since the liquid crystal molecules in the liquid crystal layer 5 have a positive dielectric anisotropy, the major axis of the liquid crystal molecules is in a normal direction (typically perpendicular) to the surfaces of the glass substrates 2 and 3. Rearrange. When light enters the liquid crystal panel 1 from the light source 40, the plane of polarization of the light (polarized light) transmitted through the lower polarizing plate 24 does not rotate while passing through the liquid crystal layer 5. Since the polarizing plates 14 and 24 are arranged in crossed Nicols, the polarized light that has passed through the liquid crystal layer 5 cannot pass through the upper polarizing plate 14. Therefore, when viewed from the opposite side (upper side) with respect to the light source 40, the liquid crystal panel 1 displays black.

  However, when the liquid crystal panel 1 has alignment defects such as point defects or rubbing streaks with minute foreign particles as nuclei, the liquid crystal molecules in the alignment defect region cannot be sufficiently rearranged. Therefore, a position with poor alignment is visually recognized as a white line or a white point having a different threshold value. As described above, according to the inspection apparatus of the present embodiment, the liquid crystal panel 1 can be turned on without applying a voltage to the electrodes of the liquid crystal panel 1, and alignment defects that can be confirmed by lighting can be easily found. it can.

  In addition, when the polarizing axes (transmission axes) of the polarizing plates 14 and 24 are arranged so as to be parallel (so-called parallel Nicol arrangement), white display is obtained when a voltage is applied, and the position of alignment failure is a threshold. It is visually recognized as a black line or a black dot with different values.

  By passing through the above inspection process, the bonded liquid crystal substrate 1 in which the alignment defect is found can be rejected. On the other hand, with respect to the bonded liquid crystal substrate 1 in which no alignment failure was found, after a chamfering (polishing) step, strip-like division and single-piece division were performed, and a plurality of pieces (4 in this embodiment) were obtained from the bonded liquid crystal substrate 1. Sheet) LCD panel. Further, a liquid crystal panel is manufactured by attaching a polarizing plate and mounting a driver IC.

(Embodiment 2)
FIG. 5 is a schematic cross-sectional view for explaining the operation of the inspection apparatus according to the second embodiment. In FIG. 5, components having substantially the same functions as the components of the inspection apparatus of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The inspection apparatus according to the present embodiment is different from the inspection apparatus according to the first embodiment in that elastic members 16 and 26 are formed on the peripheral edges of the transparent dielectric resin layers 13 and 23.

  FIG. 6 is a plan view of the upper substrate 10 of the inspection apparatus according to the present embodiment, as viewed from the lower side (light source 40 side). The elastic member 16 is a member having elasticity such as silicon rubber. The formation pattern of the elastic member 16 is an open loop shape having open ends 16a and 16b, and has an opening 16c in plan view. The thickness of the elastic member 16 is about 1 mm. The elastic member 16 can be formed by transfer or the like.

  When both surfaces 1a and 1b of the bonded liquid crystal substrate 1 are sandwiched between both substrates 10 and 20, the elastic members 16 and 26 of both substrates 10 and 20 come into contact with both surfaces 1a and 1b of the bonded liquid crystal substrate 1, respectively. At this time, gaps 50 and 60 sandwiched between the bonded liquid crystal substrate 1, the substrates 10 and 20 and the elastic members 16 and 26 are formed. Since the gaps 50 and 60 are opened by the opening 16c of the elastic member 16, when the air outside the inspection apparatus is sucked and decompressed by a vacuum chamber or the like, the air in the gaps 50 and 60 is also sucked. , Depressurize. Since the elastic members 16 and 26 have elasticity, the distance between the both surfaces 1a and 1b of the bonded liquid crystal substrate 1 and both the substrates 10 and 20 becomes uniform in the plane as the pressure in the gaps 50 and 60 is reduced. Is done. That is, the elastic members 16 and 26 function as spacers that make the distances of the gaps 50 and 60 uniform within the surface.

  When the distance between both surfaces 1a and 1b of the bonded liquid crystal substrate 1 and both substrates 10 and 20 is made uniform in the plane, the electric field strength generated in the normal direction of the liquid crystal panel 1 surface is made uniform in the plane. Therefore, the plurality of liquid crystal panels 1 formed on the bonded liquid crystal substrate 1 can be lit uniformly.

  In the present embodiment, the elastic member 16 has only one opening 16a, but there may be a plurality of openings 16a. What is necessary is just to set suitably the number and diameter of the opening 16a within the range which can decompress | depressurize the space | gap 50,60.

(Other embodiments)
In the first and second embodiments, the case where four liquid crystal panels are multi-sided from one bonded liquid crystal substrate 1 has been described. However, the present invention can also be applied to the case where one liquid crystal panel is manufactured from one bonded liquid crystal substrate 1 without dividing the bonded liquid crystal substrate 1.

In the first and second embodiments, the glass substrates 11 and 21 are used. However, a light-transmitting plastic substrate may be used instead of the glass substrate. In place of the transparent dielectric resin layers 13 and 23, an inorganic dielectric layer made of SiO _x , GeO _x , SiN _x , SiON, or the like may be used. These inorganic dielectric layers can be formed by sputtering.

  Although the liquid crystal panel 1 shown in Embodiments 1 and 2 is a transmission type, the present invention can be applied to a reflection type or a reflection / transmission liquid crystal panel. For example, in the case of the reflective liquid crystal panel 1, in the inspection apparatus, the lower substrate 20 may not be transparent. Therefore, the substrate 21, the electrode 22, and the dielectric resin layer 23 do not have to be transparent. Further, the lower polarizing plate 24 may not be provided.

In the first and second embodiments, the operation mode of the liquid crystal panel 1 is TN (Twisted Nematic).
) Mode is used, but other known modes may be used. For example, STN (Super Twisted Nematic) mode, ECB (Electrically Controlled Birefringence) mode, OCB (Optically Compensated Birefringence) mode, FLC (Ferroelectric)
Liquid Crystal (GH) mode, GH (Guest-Host) mode, PDLC (Polymer Dispersed Liquid Crystal) mode, and the like. In the IRIS (Internal Reflection Inverted Scattering) mode in which the PDLC is twist-oriented, the polarizing plates 14 and 24 are not necessary.

  In Embodiments 1 and 2, TFTs are used as active matrix drive elements, but other field effect transistors such as MOS transistors may be used. Further, MIM (Metal Insulator Metal), BTB (back-to-back diode), diode ring, varistor, plasma switching, or the like may be used.

  The liquid crystal panel manufactured by the method of the present invention can be used not only as a liquid crystal display element but also as an image shift element for sequentially shifting pixels optically and a parallax barrier element capable of displaying a three-dimensional image.

It is a top view which shows a bonded liquid crystal substrate typically. It is the II-II sectional view taken on the line in FIG. It is sectional drawing which shows the inspection apparatus of Embodiment 1 typically. FIG. 5 is a schematic cross-sectional view for explaining the operation of the inspection apparatus according to the first embodiment. FIG. 10 is a schematic cross-sectional view for explaining the operation of the inspection apparatus according to the second embodiment. It is a top view of the upper board | substrate 10 of the inspection apparatus in Embodiment 2.

Explanation of symbols

1 Bonded liquid crystal substrate (liquid crystal panel)
DESCRIPTION OF SYMBOLS 1a Outer side surface 1b Outer side surface 2 Glass substrate 3 Glass substrate 4 Perimeter seal 5 Liquid crystal layer 6 Terminal 10 Upper substrate 11 Glass substrate 12 Transparent electrode 13 Transparent dielectric resin layer 14 Polarizing plate 15 Line 16 Elastic member 16a Open end 16b Open end 16c Open 20 Lower substrate 21 Glass substrate 22 Transparent electrode 23 Transparent dielectric resin layer 24 Polarizing plate 25 Line 26 Elastic member 30 DC power source 40 Light source 50 Gap 60 Gap

Claims (4)

A method of manufacturing a liquid crystal panel from the bonded liquid crystal substrate, comprising the step of inspecting a bonded liquid crystal substrate in which two substrates are bonded via a liquid crystal layer,
The inspection step includes a step of arranging a pair of electrodes, each covered with a dielectric layer, on both outer sides of the bonded liquid crystal substrate;
Applying a voltage to the pair of electrodes;
A method for manufacturing a liquid crystal panel, comprising a step of causing light to enter the bonded liquid crystal substrate. An apparatus for inspecting a bonded liquid crystal substrate in which two substrates are bonded via a liquid crystal layer,
A pair of substrates disposed on both outer sides of the bonded liquid crystal substrate;
Electrodes respectively formed on the pair of substrates;
A dielectric layer covering the electrode;
An inspection apparatus having a power source for applying a voltage to the electrode.   The inspection apparatus according to claim 2, wherein each of the pair of substrates includes an elastic member that is formed on a peripheral edge of the dielectric layer and has an opening in a plan view.   The inspection apparatus according to claim 2, wherein the liquid crystal panel is a liquid crystal display panel.

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