JP2008225398A - Manufacturing method of liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of easily removing an unnecessary part of one substrate left covering an electrode lead-out part for a liquid crystal display element using flexible substrates and provided with the electrode lead-out part on the other substrate exposed in a recessed part of the one substrate. <P>SOLUTION: A side 122 of the recessed part 12 of the one substrate which crosses lead-out electrodes is half-cut, and sides 121 and 124 of the recessed part 12 of the one substrate which do not cross the lead-out electrode are full-cut. Then the substrate left in a strip or single-cell state at a position (a recessed part of the upper substrate) opposed to the electrode lead-out part is removed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate processing method for exposing connection electrodes to a liquid crystal display element using a flexible substrate such as plastic.

  A liquid crystal display device using a plastic plastic substrate has been put into practical use as a display panel of a mobile phone taking advantage of its light weight and thin properties. Recently, attention has been focused on the features of being hard to break, being bent, and having a high degree of freedom in planar shape, and various applied products have been proposed.

  Since a driving signal must be supplied to the display electrode from an external circuit, the liquid crystal display element usually has a region where the electrode is exposed for connection to the external circuit (hereinafter referred to as an electrode extraction portion). . In the case of a liquid crystal display element using a glass substrate, since this electrode extraction portion has a structure in which one substrate extends from the display area, the other glass substrate facing the other portion covers the electrode extraction portion until the middle of the process. ing. Therefore, the boundary line between the display unit and the electrode extraction unit (actually outside the seal, hereinafter referred to as a marking line) is scratched (scratched) with respect to the other substrate, and the other substrate is exposed so that the electrode extraction unit is exposed. Of the board. On the other hand, since a liquid crystal display element using a plastic substrate is flexible and cannot be divided, initially the liquid crystal display element is divided into a single piece, and then a position corresponding to a marking line is cut off to form an electrode. The other board | substrate which opposes the taking-out part was removed. Since the take-out electrode should not be damaged at the time of cutting, the opposite substrate was cut so as to remain about 10 μm (also called half cut). However, since it was difficult to leave it thin, the extraction electrode was often damaged, so the following full cut method and half cut method were proposed.

  As an example of the full-cut method, “a substrate made of two plastic films each provided with an electrode in each of a plurality of sections corresponding to one display element (hereinafter referred to as a“ mother substrate ”) is bonded to each section. In a method of manufacturing a liquid crystal display element in which liquid crystal is sealed in each substrate gap and then cut into individual sections and divided into individual cells, the electrode extraction portion of the other mother substrate is attached before the two mother substrates are bonded together There is a technique of “removing the portion facing the window in a window shape” (Reference 1). This is because an opening is provided in a region facing the electrode extraction portion in advance by pressing or the like with respect to the other mother substrate, and the electrode extraction portion is exposed when the substrates are overlapped.

  However, in the full cut method in which holes are formed in the mother substrate in advance as in Document 1, distortion is concentrated toward the opening due to heat and pressure applied in the middle process such as the bonding process of the mother substrate. Flatness could not be secured. Therefore, before superimposing the substrates, the other substrate that covered the electrode extraction part after half-cutting the position corresponding to the marking line of the other opposing substrate and cutting out a single liquid crystal display element from the mother substrate The method of tearing off and exposing the electrode extraction part (hereinafter referred to as half-cut method) was shown (Reference 2). In this half-cut method, the half-cut sections are balanced so that they are pressed against each other at the time of heating and pressurization, so that the deterioration of flatness is remarkably reduced as compared with the above-described full-cut method.

As another form of the full cut method that can obtain the same effect, there is a method of inserting a slit instead of an opening. For example, Document 3 has a description that “the square hole removal in this step may be replaced with two slits, and may be determined depending on the difficulty of the processing method”. Here, the square hole punching corresponds to an opening, and one of the two slits can be replaced by the outer shape processing, so that it can be considered substantially as one slit corresponding to the above-mentioned marking line. Also in this case, since the cut surfaces of the slits balance each other, there is little deterioration in flatness. When a single liquid crystal display element whose outer shape is processed is cut out, the other substrate facing the electrode extraction portion can be removed by the slit.
JP 58-43429 A JP 60-35713 A JP 59-157616 A

  So far, liquid crystal display elements made of flexible substrates such as plastics have been aimed at replacement from liquid crystal display elements made of glass substrates for the purpose of weight reduction, so that the electrode extraction part extends from the display part. It remained. When a thin and flexible circuit board (hereinafter referred to as FPC) is adhered to the electrode extraction portion of this display element, the extraction electrode may crack and break at the boundary between the display portion and the electrode extraction portion due to bending stress applied from the FPC. there were. This is because, while the display portion is composed of two substrates, the extension portion, which is an electrode extraction portion, is composed of one substrate, so that bending deformation concentrates on this boundary portion. In addition to countermeasures for this problem, a concave portion was provided on the other substrate of the liquid crystal display device for the reasons of design focusing on a large degree of freedom with respect to the outer shape of the flexible substrate and for the purpose of making the display area as wide as possible, and exposed there. There has been a demand for a structure in which an electrode extraction portion is provided on one substrate.

  If an opening is provided in advance at the position corresponding to the concave portion with respect to the other substrate by the full-cut method as in Reference 1, this structure can be realized because the electrode extraction portion is exposed when cut into a single piece. However, there is a problem that the flatness deteriorates. The half-cut method as in Reference 2 and the full-cut method with slits as in Reference 3 are methods applied to a liquid crystal display device having a structure in which the electrode extraction portion extends from the display region. Cannot be used.

  Accordingly, an object of the present invention is to provide a liquid crystal display element having an electrode extraction portion exposed from a concave portion of the other substrate, using a flexible substrate, and the other one remaining so as to cover the electrode extraction portion on one substrate. It is to provide a method for easily removing the substrate.

    The present invention provides a first extraction electrode connected to a display electrode provided on at least one of the first and second substrates having flexibility and opposing to each other, and transmitting an external drive signal to the display electrode. In a method of manufacturing a liquid crystal display element having an electrode extraction portion formed on the substrate and further including an electrode extraction portion exposed from the second substrate, the side intersecting with the extraction electrode of the second substrate is half A half-cut step for cutting, a full-cut step for full-cutting a side that does not intersect with the extraction electrode of the second substrate, and a removal step for removing a piece of the substrate remaining at a position facing the electrode extraction portion. It is a feature.

  Preferably, the method further includes a step of bonding a pair of mother substrates each having a flexibility and a region corresponding to each of the first and second substrates, and half-cutting before the step of bonding the mother substrates. Process and full cut process are performed.

  Further, the method further includes a step of bonding a pair of mother substrates each having a flexibility and a region corresponding to each of the first and second substrates, and a half-cut step is performed before the step of bonding the mother substrates. And a full cut process may be performed after the process of bonding the mother substrate.

  In addition, the liquid crystal display element manufacturing method of the present invention is characterized in that the removing step is applied in a strip state.

  The method for manufacturing a liquid crystal display element according to the present invention is characterized in that the removal step is applied after the liquid crystal display element is separated into single pieces.

  The electrode extraction portion has one side that matches the outer shape of the liquid crystal display element, and one side that faces this side intersects with the extraction electrode. The remaining two sides do not intersect with the extraction electrode. When the liquid crystal display element is cut out along the outer shape, the other substrate is half-cut along the side intersecting with the take-out electrode, and the other substrate is fully cut along two sides not intersecting with the take-out electrode. The other substrate is connected to the other substrate remaining in the display portion only by the half-cut portion. In this state, the half-cut portion is torn off, and the substrate remaining at the position facing the electrode extraction portion is removed.

  If there is a half-cut process and a full-cut process before the process of bonding one mother board to the other, the half of the area corresponding to the recesses of each section of the other mother board is halfway A side that does not coincide with the outer shape of the liquid crystal display element and does not intersect with the extraction electrode is fully cut. After that, when one and the other mother substrate are bonded together and an unnecessary part is cut off along the outer shape of the concave portion, the other substrate facing the electrode extraction portion is connected to the other substrate remaining in the display portion only by the half cut portion. It will be in a state. Therefore, the half-cut portion is torn off, and the substrate remaining at the position facing the electrode extraction portion is removed.

  When there is a half-cut process before the process of bonding one and the other mother board, and there is a full-cut process after the process of bonding the one and the other mother board, it corresponds in advance to the recesses of each section of the other mother board Only the side that intersects the extraction electrode is half-cut in the region to be processed. After pasting one and the other mother substrate together, the side that does not match the outer shape of the display element and does not intersect with the extraction electrode is fully cut, and the unnecessary portion is cut along the outer shape on the concave side. The opposite substrate is connected to the other substrate remaining in the liquid crystal portion only by the half-cut portion. Therefore, the half-cut portion is torn off, and the substrate remaining at the position facing the electrode extraction portion is removed.

  When the stripping process is applied in the strip state, the above-described full cut is completed, and the substrate remaining at the position facing the electrode extraction portion is removed by tearing off the half cut portion in the strip state.

  When the removal step is applied after separating the liquid crystal display elements into single pieces, it is preferable that there is a half-cut step before the step of attaching the mother substrate.

  As is apparent from the above description, the method for manufacturing a liquid crystal display element according to the present invention is that the liquid crystal display element having the electrode extraction portion exposed from the other substrate faces the electrode extraction portion and becomes unnecessary. The substrate can be easily removed.

  In the case where there are a half-cut process and a full-cut process before the process of bonding the one and the other mother substrates, the half-cut process and the full-cut process can be continued, so that the manufacturing process can be simplified in addition to the above effects.

  If there is a half-cut process before the process of laminating one and the other mother board, and if there is a full-cut process after the process of laminating the one and the other mother board, after bonding the mother board and heating and baking the seal Since the full cut is performed, stress due to heating and baking is not applied to the full cut portion, so that the substrate is not easily deformed in addition to the above effects.

  When the stripping process is applied in the strip state, the other substrate that is no longer necessary can be removed from the section corresponding to the liquid crystal display elements arranged in a horizontal row, so in addition to the above effects, mounting on a single jig With this, it is possible to remove a plurality of unnecessary portions, and there is an effect that work efficiency is improved.

  When the removal process is applied after separating the liquid crystal display element into a single piece, the electrode take-out portion is not exposed until the outer shape of the display element is finished, so that inadvertent contamination can be avoided in addition to the above effects. is there.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Example 1)

  FIG. 1 is an assembly diagram illustrating the layer structure of the liquid crystal display element of Example 1. FIG. As shown in FIG. 1, in the liquid crystal display element of Example 1, a lower substrate 16 corresponding to one substrate, a seal 14, and an upper substrate 11 corresponding to the other substrate are laminated. The lower substrate 16 is a polycarbonate film having a thickness of 0.1 mm, and an extraction electrode 17 made of ITO and a display electrode (not shown) are formed on the upper surface. The seal 14 is an epoxy adhesive in which conductive particles and spacers are mixed to ensure conductivity and a gap between the substrates, and thiol is added to give flexibility, and has an injection hole 13. There is a recess 15 on the opposite side. The upper substrate 11 is made of a polycarbonate film having a thickness of 0.1 mm, a display electrode (not shown) is formed on the lower surface, and has a recess 12 formed of sides 121, 122, 123. The liquid crystal held between the seal 14 and the upper and lower substrates 11, 16, the sealing material for the injection hole 13, the polarizing plate attached to the upper and lower substrates 11, 16 are omitted.

  FIG. 2 is a plan view of the liquid crystal display element of Example 1, and the same parts and members as those in FIG. The concave portion 12 of the upper substrate 11 is arranged along the outside of the concave portion 15 of the seal 14. The region of the lower substrate 16 exposed by the recess 12 of the upper substrate 11 is an electrode extraction portion, and the extraction electrode 17 is exposed. In addition, since the liquid crystal display element of a present Example assumes the case of a passive type and a static drive, the display electrode (not shown) formed in the lower surface of the upper board | substrate 11 turns into a common electrode (it is also called a common electrode), It is connected to one of the extraction electrodes 17 through conductive particles in the seal 14. The remaining extraction electrodes 17 are connected to display electrodes (also referred to as segment electrodes, not shown) on the lower substrate 16. Since the seal 14 is on the lower side of the upper substrate 16, it is indicated by a dotted line (the same applies hereinafter).

A procedure for removing the upper substrate 16 facing the electrode extraction portion will be described with reference to FIG. First, the upper substrate 11 is slit with a knife along the sides 121 and 123 of the recess 12. At this time, the lower substrate 16 may be slightly scratched, so that the slit completely penetrates the upper substrate 11 (hereinafter referred to as full cut). Next, a ruler is placed along the side 122, and the upper substrate 11 is scratched along the side 122 with a knife (hereinafter referred to as half cut). The cut amount may be about 60 microns so as not to damage the extraction electrode 17. The corner of the upper substrate to be removed is pinched and the half-cut side 122 is torn off while the ruler is fixed. The reason why the side 122 is held by the ruler when the side 122 is torn is that the seal near the side 122 is not damaged in addition to being surely torn.
(Example 2)

  A second embodiment in which half-cutting and full-cutting are performed before the mother substrate is bonded will be described with reference to FIGS. The layer structure and plan view of the second embodiment are the same as those of FIGS. 1 and 2 of the first embodiment. Parts and members corresponding to those in the first embodiment are indicated by the same numbers.

  FIG. 3 is an assembly diagram when a mother substrate having a plurality of sections corresponding to the respective liquid crystal display elements of Example 2 is bonded. The outline of the upper substrate 11 is indicated by a dotted line as a section corresponding to the display element of the upper mother substrate 31. In the concave portion of the upper substrate 11, the slit 32 and the slit 34 are fully cut in advance, and the slit 33 is half cut. The slits 32, 33, and 34 correspond to the sides 121, 122, and 123 of the recess 12 in FIG. 2, but the slits 32 and 34 protrude outward from the outer shape of the upper substrate 11. The seals 14 arranged in a matrix (one horizontal row in the figure) are formed by screen printing. The outline of the lower substrate 16 is indicated by a dotted line as a section corresponding to the liquid crystal display element of the lower mother substrate 35. A take-out electrode 17 is formed here. The display electrodes formed in the sections of the upper and lower substrates 11 and 16 are not shown. A cutting line for strips is formed between A-B and C-D. The slit 32 and the slit 34 protrude from the outline of the upper substrate 11 by about 0.2 mm as the sum of the bonding tolerance of the upper and lower mother boards 31 and the tolerance of the strip cutting line CD. Since the slit 33 is a half cut, it is indicated by a one-dot chain line (the same applies hereinafter). The slit 33 may be cut from either side of the upper mother board 31. However, if there is a cut on the front surface, it is advantageous for burr after tearing, whereas if there is a cut on the back surface, it is easy to tear. is there.

  FIG. 4 is a plan view of a strip of the second embodiment. One strip is obtained by cutting an area in which the sections corresponding to the respective liquid crystal display elements are arranged in a line from the mother substrate after being overlapped, along the cutting lines AB and CD. Since the slits 32 and 34 that have been fully cut in FIG. 3 intersect the cutting line CD, three sides of the recess 12 of the upper substrate 11 (sides that coincide with the sides 121 and 122) when the strip is formed. Is cut out and connected to the upper substrate 11 with the side 122 intersecting with the extraction electrode 17 being half-cut. The outline 41 is indicated by a mark or the like and is indicated by a broken line because there is no actual condition. The extraction electrode 17 is hidden under the upper substrate and indicated by a dotted line and thin hatching (the same applies hereinafter).

  The strip is cut along the cutting line AB so that the tips of the injection holes 13 of the seal 14 are aligned, so that the plurality of injection holes 13 can be immersed in the liquid crystal reservoir simultaneously. In this strip state, liquid crystal is injected from the injection hole 13 by a vacuum injection method, and then the injection hole 13 is sealed with an ultraviolet curable adhesive. Next, when the upper substrate of the recess 12 is removed so as to tear off the half-cut portion, the electrode extraction portion on the lower substrate 16 is exposed. Finally, the outline 41 of the liquid crystal display element is cut to separate the individual display elements. In addition, when tearing a half cut part, it is preferable to apply a ruler etc. like Example 1. FIG. If the upper substrate is removed by sealing the injection hole 13 and then tearing off the half-cut portion, unnecessary contamination of the electrode extraction portion in the liquid crystal injection process and the injection hole 13 sealing process is performed. Can be avoided.

  FIG. 5 is a flowchart of the manufacturing process of the second embodiment. First, electrodes are formed on the ITO surfaces of the upper and lower mother substrates 31 and 35 by photolithography. Next, an alignment film made of polyimide is printed and rubbed. Thereafter, the slit 33 is formed on the upper mother substrate 31 using a film cutter capable of setting a cutting position and a cutting amount under half-cut conditions. Next, the upper mother substrate 31 is rotated 90 degrees to form slits 32 and 34 under full cut conditions. Next, the seal 14 is printed by a seal printer, and the upper and lower mother substrates 31 and 35 are overlapped so that the ITO surfaces face each other. The mother substrate is pressurized and baked at about 120 ° C. After making the mother substrate into a strip, liquid crystal injection and sealing are performed, and unnecessary portions of the upper substrate 11 covering the electrode extraction portion are removed. Finally, it is separated into individual liquid crystal display elements (single cells).

In addition, the half cut and the full cut are performed immediately before the pressurization / firing which is the last heat process, and the deformation risk of the half cut part and the full cut part is minimized. When it is desired to avoid contamination or breakage of the extraction electrode 17 in the step of separating into single cells, the substrate facing the electrode extraction portion may be removed after being separated into single cells.
(Example 3)

  6 to 8, a liquid crystal display element that performs a half cut before bonding the mother substrate, and performs a full cut after bonding the mother substrate, and covers the electrode extraction portion after the outer shape processing. Example 3 for a liquid crystal display device that removes the above will be described. The parts and members corresponding to those in Examples 1 and 2 are indicated by the same numbers.

  FIG. 6 is an assembly diagram when a mother substrate having a plurality of sections corresponding to each liquid crystal display element of Example 3 is bonded. The difference from Example 2 in FIG. 3 is that the protrusion of the injection hole 13 of the seal 14 is long and the strip cutting lines AB and CD are shifted vertically.

  FIG. 7 is a plan view of a strip of the third embodiment. As in the second embodiment, a single strip is obtained by cutting a region where the sections corresponding to the respective liquid crystal display elements are arranged in a line from the mother substrate after being overlapped by cutting lines AB and CD. It is. Since the cutting lines AB and CD are shifted as described above, there is no portion where the outline 71 of the liquid crystal display element and the cutting lines AB and CD coincide. The slits 32 and 34 are formed by overlapping the mother substrates, pressurizing and baking the seal, and then fully cutting only the upper mother substrate 31. Similar to the second embodiment, this full cut may cause the lower mother substrate 35 to be slightly scratched. In addition, the slits 32 and 34 protrude outside the outline 71. Note that the cutting line 72 for separating each liquid crystal display element from the strip is indicated by a mark or the like, and is indicated by a broken line because there is no actual state.

  Although the cutting line AB is outside the outer shape 71 of the liquid crystal display element, since the projection of the injection hole 13 of the seal 14 is extended as described above, the tip of the injection hole 13 is aligned with the cutting line AD. Disconnected. In this strip state, liquid crystal is injected and the injection hole 13 is sealed. Next, the strip is cut along the cutting line 72 to separate individual liquid crystal display elements. Finally, the liquid crystal display element is extracted with a mold so as to fit the outer shape 71. At this time, the upper substrate covering the electrode extraction portion is connected to the upper substrate 11 only by the half cut portion (corresponding to the slit 33). Similar to the second embodiment, the slit 33 is torn off, and the take-out electrode 17 is exposed from the recess 12 of the upper substrate.

  FIG. 8 is a flowchart of the manufacturing process of the third embodiment. The process from the electrode formation to the half cut is the same as that of the second embodiment. Next, the seal 14 is printed by a seal printer, and the upper and lower mother substrates 31 and 35 are overlapped so that the ITO surfaces face each other, and then the mother substrate is pressurized and baked at about 120 ° C. Next, slits 33 and 34 are formed under full cut conditions. A film cutter is used in the same manner as in Example 2 for half-cutting and full-cutting. After making this mother substrate into a strip, liquid crystal injection and sealing are performed to separate individual liquid crystal display elements (single cells). The single cell is further punched to fit the outer shape 71, and finally the unnecessary portion of the upper substrate 11 covering the electrode extraction portion is removed.

  In Example 3, the full cut was performed after pressurization and firing, but the full cut may be in a strip shape or a single cell state. In this case, the manufacturing time is shortened if a slit is provided in the mold. Further, in Example 3, the final outer shape processing was performed with a mold after being separated into single pieces, but the outer shape processing may be performed in a strip shape. The method of the third embodiment is effective when a curved line is included in the outer shape, and particularly effective when there is a curved part on the side where the electrode extraction part exists. In addition, since the take-out electrode is covered with the opposing substrate until the final process, it is less susceptible to inadvertent contamination in the intermediate process as compared with a method in which an opening is provided as a full cut in advance.

In Examples 1, 2, and 3, the concave portion 12 is rectangular, but the concave portion may be trapezoidal or U-shaped. A mold or laser may be used for half-cutting or full-cutting. In a liquid crystal display element that performs display control using an electric field parallel to the substrate surface, a display electrode is formed only on one or the other substrate. The present invention can be applied to both a multi-flex liquid crystal display device and an active matrix display device. An electrode driving IC may be mounted on the electrode lead-out portion.

It is an assembly drawing which shows the layer structure of the liquid crystal display element of Example 1, 2, 3 of this invention. It is a top view of the liquid crystal display element of Example 1, 2, 3 of this invention. It is an assembly drawing of the mother board | substrate of Example 2 of this invention. It is a top view of the strip of Example 2 of this invention. It is a flowchart of the manufacturing process of Example 2 of this invention. It is an assembly drawing of the mother board | substrate of Example 3 of this invention. It is a top view of the strip of Example 3 of this invention. It is a flowchart of the manufacturing process of Example 3 of this invention.

Explanation of symbols

11 Upper substrate 12 Upper substrate recess 121, 122, 123 Side of recess 13 Injection hole 14 Seal 15 Seal recess 16 Lower substrate 17 Extraction electrode 31 Upper mother substrate 32, 34 Full cut slit 33 Her cut slit 35 Lower side Mother board 41, 71 Outline line AB, CD, 72 cutting line of display element

Claims (5)

A take-out electrode connected to a display electrode provided on at least one of the first and second substrates having flexibility and opposing to each other and transmitting an external drive signal to the display electrode is provided on the first substrate. And a method of manufacturing a liquid crystal display element comprising an electrode extraction portion formed such that the extraction electrode is exposed from the second substrate.
A half-cut step of half-cutting a side intersecting with the extraction electrode of the second substrate;
A full-cut step of full-cutting the side of the second substrate that does not intersect with the extraction electrode;
A removal step of removing fragments of the substrate remaining at a position facing the electrode extraction portion;
A method for producing a liquid crystal display element, comprising: A step of bonding a pair of mother substrates having flexibility and having regions corresponding to the first and second substrates, respectively;
The method for manufacturing a liquid crystal display element according to claim 1, wherein the half-cut step and the full-cut step are performed before the step of bonding the mother substrate. A step of bonding a pair of mother substrates having flexibility and having regions corresponding to the first and second substrates, respectively;
2. The method of manufacturing a liquid crystal display element according to claim 1, wherein the half-cut process is performed before the process of bonding the mother substrate, and the full-cut process is performed after the process of bonding the mother substrate.   The method for manufacturing a liquid crystal display element according to claim 1, wherein the removing step is applied in a strip state.   The method for manufacturing a liquid crystal display element according to claim 1, wherein the removing step is applied after separating the liquid crystal display element into a single piece.

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