JP2020071362A - Liquid crystal display and method for manufacturing the same - Google Patents

Abstract

To provide a liquid crystal display that easily controls the gap between substrates of a liquid crystal panel, and a method for manufacturing the same.SOLUTION: There is provided a liquid crystal display in which: a center part of a liquid crystal panel 1 and a support substrate (circuit board 5) are adhered with a first adhesive member (double-sided tape 21), an outer peripheral part outside the center part of the liquid crystal panel 1 and the support substrate are adhered with a second adhesive member (protective resin 22) having cure-shrinkage properties, and the liquid crystal panel 1 is deflected such that the cure-shrinkage of the second adhesive member brings the outer peripheral part of the liquid crystal panel 1 closer to the support substrate. Also provided is a method for manufacturing the liquid crystal display. According to the present invention, the cure-shrinkage of the second adhesive member can make substantially uniform the gap between a first substrate 2 and a second substrate 3 of the liquid crystal panel 1, and facilitate control of the gap.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid crystal display device and a method for manufacturing the same.

  Liquid crystal display devices have advantages such as thinness, miniaturization, and driving with low power consumption. In recent years, image display has been performed in the field of small electronic devices such as mobile devices, projectors, viewfinders, and HMDs. Widely used as a device.

  FIG. 5 is a top view showing a conventional liquid crystal display device. 6A and 6B are a sectional view taken along the line AA and a sectional view taken along the line BB, respectively, showing a conventional liquid crystal display device. In the liquid crystal display device according to the related art, the liquid crystal panel 1 includes, for example, a first substrate 2 made of a light-shielding substrate such as silicon and a second substrate 3 made of a translucent substrate such as glass in which a spacer 9 is mixed. Further, the liquid crystal panel 7 is a reflection type liquid crystal panel in which a liquid crystal 7 is enclosed in a gap formed by being bonded via a peripheral seal 4. A reflective electrode (pixel electrode) and an alignment film are formed on the surface of the first substrate 2, and a transparent electrode (counter electrode) and an alignment film are formed on the surface of the second substrate 3 facing the reflective electrode (pixel electrode). A gap formed between the first substrate 2 and the second substrate 3 via the peripheral seal 4 and the spacer 9 is made of a ferroelectric liquid crystal via an injection port provided in a part of the peripheral seal 4. The liquid crystal 7 is injected, and the injection port is sealed with the sealing material 8, so that the liquid crystal 7 is hermetically sealed (enclosed) in the gap in the region surrounded by the peripheral seal 4. The liquid crystal panel 1 is mounted on the circuit board 5 and adhered to the circuit board 5 with a double-sided tape 6. The double-sided tape 6 has a shape that covers the entire lower surface of the first substrate 2. One end of the first substrate 2 projects laterally more than one end of the second substrate 3, and a part of the reflective electrode provided on the projected part is electrically connected to the electrode of the circuit board 5 via the wire 11. Connected to each other. The other end of the second substrate 3 projects laterally more than the other end of the first substrate 2, and a part of the counter electrode provided on the projecting portion has a portion of the circuit board 5 through the conductive resin 10. Is electrically connected to the electrode.

  In the liquid crystal panel 1, since the spacer 9 exists in the region where the peripheral seal 4 is arranged, the gap between the substrates (between the first substrate 2 and the second substrate 3) is uniform in this region, Since the spacer 9 does not exist in the region surrounded by the peripheral seal 4, the gap between the substrates tends to be nonuniform in this region due to the contraction of the liquid crystal 7 caused by the decrease in temperature. Specifically, due to the contraction of the liquid crystal 7, the central portions of the first substrate 2 and the second substrate 3 tend to be curved (concave inward) so as to be convex in a direction in which they approach each other. In particular, when the liquid crystal 7 is a ferroelectric liquid crystal, the liquid crystal molecules 13 of the liquid crystal 7 form the layer structure 14 so as to extend in the direction orthogonal to the rubbing direction of the alignment film as shown in FIG. The first substrate 2 and the second substrate 3 have a tendency that the central portions thereof are not concentrically recessed, but are recessed into an elliptical shape or a rugby ball shape extending along the rubbing direction as shown by a broken line in FIG. is there. In such a state where the gaps between the substrates are non-uniform, color unevenness or the like occurs in the image displayed by the liquid crystal panel 1, and the image quality deteriorates.

  In order to solve this problem, in a conventional liquid crystal display device, before the liquid crystal 7 is injected between the substrates, an adhesive 12 having a curing shrinkage property is applied to the outer peripheral portions of the first substrate 2 and the second substrate 3. By coating and curing, the curing shrinkage pulls the outer peripheral portions of the first substrate 2 and the second substrate 3 toward each other, so that the peripheral seal 4 or the spacer 9 serves as a fulcrum of the first substrate 2 and the second substrate 3. The central portions are bent in directions away from each other, and the central portions of the gaps between the substrates are bulged outward in advance. In this state, if the liquid crystal 7 is heated and injected into the gap between the substrates and then the temperature is lowered, the central portions of the first substrate 2 and the second substrate 3 are bent due to the contraction of the liquid crystal 7 in a direction in which they approach each other. As a result, the central portions of the first substrate 2 and the second substrate 3 become flat, and the gaps between the substrates become uniform as shown in FIG. (For example, see Cited Document 1)

Patent No. 5713755

  In the conventional liquid crystal display device, it is difficult to control the amount and position of the adhesive applied to the outer peripheral portions of the first substrate and the second substrate of the liquid crystal panel, and thus it is difficult to control the gap between the substrates. there were.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device in which the gap between the substrates of a liquid crystal panel can be easily controlled, and a manufacturing method thereof.

  A liquid crystal panel in which liquid crystal is sealed in a gap between the first substrate and the second substrate, which is formed by bonding a first substrate and a second substrate with a seal member at a predetermined distance; In a liquid crystal display device comprising: a supporting substrate that supports the liquid crystal panel, the central portion of the liquid crystal panel and the supporting substrate are bonded together by a first adhesive member, and the outer peripheral portion of the liquid crystal panel is outside the central portion and the outer peripheral portion. A supporting substrate and a second adhesive member having a curing shrinkage property are adhered to each other, and the liquid crystal panel is bent so that the outer peripheral portion of the liquid crystal panel approaches the supporting substrate due to the curing contraction of the second adhesive member. Use as a display device.

  A portion excluding two corner portions facing each other across the central portion of the liquid crystal panel and the support substrate are bonded by the first adhesive member, and the two corner portions of the liquid crystal panel and the support substrate are joined together. It may be a liquid crystal display device adhered by the second adhesive member.

  A liquid crystal panel in which liquid crystal is sealed in a gap between the first substrate and the second substrate, which is formed by bonding a first substrate and a second substrate with a seal member at a predetermined distance; In a method of manufacturing a liquid crystal display device comprising: a supporting substrate supporting the substrate, a step of bonding a central portion of the liquid crystal panel and the supporting substrate with a first adhesive member, and an outer side of the central portion of the liquid crystal panel. A step of adhering an outer peripheral portion of the liquid crystal panel and the support substrate with a second adhesive member having a curing shrinkage property, and the liquid crystal so that the outer peripheral portion of the liquid crystal panel approaches the support substrate by the curing shrinkage of the second adhesive member. A method of manufacturing a liquid crystal display device, comprising: a step of bending a panel.

  A portion excluding two corner portions facing each other across the central portion of the liquid crystal panel and the support substrate are bonded by the first adhesive member, and the two corner portions of the liquid crystal panel and the support substrate are joined together. A method for manufacturing a liquid crystal display device, in which the second adhesive member is used for adhesion, may be used.

  According to the present invention, it is possible to provide a liquid crystal display device in which a gap between substrates of a liquid crystal panel can be easily controlled and a manufacturing method thereof.

The top view which shows the embodiment of the liquid crystal display device by this invention. (A) AA sectional view showing the embodiment of the liquid crystal display device by this invention, (b) BB sectional view. The top view which shows the double-sided tape shape in embodiment of the liquid crystal display device by this invention. The top view which shows the modification of the double-sided tape shape in embodiment of the liquid crystal display device by this invention. Top view showing a liquid crystal display device according to the prior art (A) A-A sectional view showing the liquid crystal display device by a prior art, (b) BB sectional view

  FIG. 1 is a top view showing an embodiment of a liquid crystal display device according to the present invention. 2A and 2B are (a) AA sectional view and (b) BB sectional view showing an embodiment of the liquid crystal display device according to the present invention. FIG. 3 is a top view showing the shape of the double-sided tape in the embodiment of the liquid crystal display device according to the present invention. In the liquid crystal display device according to this embodiment, the liquid crystal panel 1 includes, for example, a first substrate 2 made of a light-shielding substrate such as silicon and a second substrate 3 made of a light-transmitting substrate such as glass mixed with a spacer 9. The liquid crystal panel 7 is a reflection type liquid crystal panel in which a liquid crystal 7 is enclosed in a gap formed by being bonded via the peripheral seal 4. A reflective electrode (pixel electrode) and an alignment film are formed on the surface of the first substrate 2, and a transparent electrode (counter electrode) and an alignment film are formed on the surface of the second substrate 3 facing the reflective electrode (pixel electrode). A gap formed between the first substrate 2 and the second substrate 3 via the peripheral seal 4 and the spacer 9 is made of a ferroelectric liquid crystal via an injection port provided in a part of the peripheral seal 4. The liquid crystal 7 is injected, and the injection port is sealed with the sealing material 8, so that the liquid crystal 7 is hermetically sealed (enclosed) in the gap in the region surrounded by the peripheral seal 4.

  The liquid crystal panel 1 is mounted on the circuit board 5 and adhered to the circuit board 5 with a double-sided tape 21. The shape of the double-sided tape 21 is, as shown in FIG. It is a parallelogram in which an area of a right triangle having one side in the hand direction as a long side is cut off. In this parallelogram, two sides corresponding to the hypotenuse of the cut right triangle extend along the rubbing direction of the alignment film. Due to the shape of the double-sided tape 21 as described above, a space between the corners 2a and 2b of the first substrate 2 and the circuit board 5 does not exist as shown in FIG. Right-angled triangle gaps 23a and 23b are formed. The gaps 23a and 23b are arranged at both ends in the extending direction of the layer structure 14 of the liquid crystal 7 (sides facing each other across the rubbing direction of the alignment film). The shape and positional relationship of the gaps 23a and 23b are suitable for correcting the dents of the liquid crystal panel 1 which are elliptical or rugby ball-shaped extending along the rubbing direction as shown by the broken line in FIG.

  One end of the first substrate 2 projects laterally more than one end of the second substrate 3, and a part of the reflective electrode provided on the projected part is electrically connected to the electrode of the circuit board 5 via the wire 11. Connected to each other. The other end of the second substrate 3 projects laterally more than the other end of the first substrate 2, and a part of the counter electrode provided on the projecting portion has a portion of the circuit board 5 through the conductive resin 10. Is electrically connected to the electrode.

  The entire periphery of the liquid crystal panel 1 is covered with a protective resin 22 having electrical insulation and curing shrinkage, whereby the outer peripheral portion of the liquid crystal panel 1 and the wires 11 are protected from the outside. Part of the protective resin 22 also intervenes in the gaps 23a and 23b between the corners 2a and 2b of the first substrate 2 and the circuit board 5, and the curing shrinkage of the intervening protective resin 22 causes the first substrate to shrink. The two corners 2a, 2b are pulled toward the side closer to the circuit board 5, and the stress causes the entire first board 2 to be bent so as to be convex upward. In addition, the second substrate 3 mechanically coupled to the first substrate 2 via the peripheral seal 4 is also affected by the bending of the first substrate 2, and sometimes adheres to the outer peripheral portion of the second substrate 3. Under the influence of the curing shrinkage of the protective resin 22 present, the entire second substrate 3 is bent so as to be convex upward like the first substrate 2. In this way, the first substrate 2 and the second substrate 3 are similarly bent, so that the gap between the first substrate 2 and the second substrate 3 is substantially uniform at least in the image display region. ..

  The liquid crystal display device according to this embodiment is manufactured, for example, as follows. First, after bonding the first substrate 2 and the second substrate 3 constituting the liquid crystal panel 1 with the peripheral seal 4, or after injecting the liquid crystal 7 between these substrates, the liquid crystal panel is measured using an optical wavefront measuring device or the like. The surface flatness (surface accuracy) of No. 1 is measured, and the shape of the double-sided tape 21 and the characteristics of the protective resin 22 are determined based on the measurement result. For example, as the shape of the double-sided tape 21, an appropriate shape is selected from a plurality of types prepared in advance, and the characteristic of the protective resin 22 is that the double-sided tape 21 has a low viscosity that easily penetrates into a narrow gap of the same thickness as the double-sided tape 21. Is selected.

  Next, the double-sided tape 21 is attached to a predetermined position of the circuit board 5, and the first substrate 2 of the liquid crystal panel 1 is bonded onto the double-sided tape 21. Subsequently, the electrode of the first substrate 2 (a part of the reflective electrode) and the electrode of the circuit board 5 are connected by a wire 11, and the electrode of the second substrate 3 (a part of the counter electrode) and the electrode of the circuit board 5 are connected. Are connected by a conductive resin 10.

  Next, the protective resin 22 is applied so as to cover the entire periphery of the liquid crystal panel 1 so that the outer peripheral portion of the liquid crystal panel 1 and the wires 11 are covered with the protective resin 22, and a part of the protective resin 22 is covered with the first resin. The gaps 23 a and 23 b between the corners 2 a and 2 b of the one substrate 2 and the circuit board 5 are interposed. At this time, the protective resin 22 may or may not be completely filled in the gaps 23a and 23b. However, if the protective resin 22 is completely filled, the protective resin 22 interposed in the gaps 23a and 23b. It is possible to control the amount and the position of the gaps in accordance with the shapes of the gaps 23a and 23b. Even if the protective resin 22 is not completely filled in the gaps 23a and 23b, the area in which the protective resin 22 is interposed is limited within the range of the gaps 23a and 23b, so that the amount and position of the protective resin 22 are controlled. Easy to do.

  Next, the protective resin 22 is cured by subjecting the protective resin 22 to a predetermined curing treatment (heat treatment or the like). When the protective resin 22 is cured, the curing shrinkage causes tension in the gaps 23a, 23b between the corners 2a, 2b of the first substrate 2 and the circuit board 5, and the tension causes the first substrate 2 and the second substrate 2 as a whole, the double-sided tape 21 serves as a fulcrum and is bent so as to be convex upward as shown in FIG. 2B, and accordingly, the gap between the first substrate 2 and the second substrate 3 is increased. It becomes a substantially uniform state. At this time, the gap between the first substrate 2 and the second substrate 3 may be uniform only in the region in which the liquid crystal 7 is sealed, and particularly only in the image display region of the region. good.

  The method of bending the first substrate 2 and the second substrate 3 shown in FIG. 2 is a conceptual example, and how the first substrate 2 and the second substrate 3 actually bend depends on the manufacturing process. It may differ depending on the shape of the liquid crystal panel 1 immediately after, the shape of the double-sided tape 21, the coating amount of the protective resin 22, and the like. Depending on the overall balance of the stress acting on the liquid crystal panel 1, both the first substrate 2 and the second substrate 3 do not bend, but only one of the first substrate 2 and the second substrate 3 is substantially bent. It is possible to bend to.

  FIG. 4 is a top view showing a modified example of the double-sided tape shape in the liquid crystal display device according to the present invention. The shape of the double-sided tape 21 is the same as that shown in FIG. 3, and for example, as shown in FIG. 4A, the double-sided tape 21 is formed in a rectangular area facing the first substrate 2 of the liquid crystal panel 1. An equilateral triangular region facing the two corners 2a, 2b of the substrate 2 is cut away, or a rectangular shape facing the first substrate 2 of the liquid crystal panel 1 as shown in FIG. 4B. A polygon having a shape in which a right triangle (right triangle having one side in the longitudinal direction of the first substrate 2 as a long side) facing the two corners 2a and 2b of the first substrate 2 with respect to the region is cut off is formed. Can be mentioned. Also by using these shapes, the first substrate 2 and the second substrate 3 of the liquid crystal panel 1 can be bent as shown in FIG. However, the shape of the double-sided tape 21 is not limited to the above-mentioned shape, and may be other shapes.

  The area where the double-sided tape 21 does not exist (the area where the protective resin 22 is interposed) between the first substrate 2 and the circuit board 5 is provided in any area of the area of the first substrate 2 excluding the central portion. However, if it is provided in a region facing the corner of the first substrate 2 as in the above embodiment, the direction and magnitude of the stress generated by the curing shrinkage of the protective resin 22 interposed in that region can be controlled. Easy to do.

  The double-sided tape 21 can be replaced with an adhesive or the like.

  The circuit board 5 can be replaced with a board or the like having no circuit function.

  The adhesive for bending the first substrate 2 and the second substrate 3 of the liquid crystal panel 1 may be an adhesive provided separately from the protective resin 22. However, if the protective resin 22 is used, the configuration can be simplified. This adhesive may be provided only around the gap (for example, the gaps 23a and 23b) between the first substrate 2 and the circuit board 5.

  The liquid crystal 7 may be a liquid crystal other than the ferroelectric liquid crystal.

  The spacer 9 is not essential and can be omitted.

  The present invention can also be applied to a liquid crystal display device using a transmissive liquid crystal panel in which the first substrate 2 is a translucent substrate such as glass. In that case, for example, the double-sided tape 21 and the circuit board 5 facing the image display area may be provided with an opening or a transparent portion for transmitting light to ensure light transmission.

1 Liquid Crystal Panel 2 First Substrate 2a Corner 2b Corner 3 Second Substrate 4 Peripheral Seal 5 Circuit Board 6 Double Sided Tape 7 Liquid Crystal 8 Sealing Material 9 Spacer 10 Conductive Resin 11 Wire 12 Adhesive 13 Liquid Crystal Molecule 14 Layer Structure 21 Double Sided Tape 22 Protective resin 23a Gap 23b Gap

Claims (4)

A liquid crystal panel in which a liquid crystal is sealed in a gap between the first substrate and the second substrate formed by bonding a first substrate and a second substrate with a seal member at a predetermined distance,
A support substrate for supporting the liquid crystal panel,
In a liquid crystal display device including
Bonding the central portion of the liquid crystal panel and the support substrate with a first adhesive member,
The outer peripheral portion outside the central portion of the liquid crystal panel and the supporting substrate are bonded by a second adhesive member having curing shrinkage,
The liquid crystal panel is bent so that the outer peripheral portion of the liquid crystal panel approaches the support substrate due to curing shrinkage of the second adhesive member.
A liquid crystal display device characterized by the above.   A portion excluding two corner portions facing each other across the central portion of the liquid crystal panel and the support substrate are bonded by the first adhesive member, and the two corner portions of the liquid crystal panel and the support substrate are joined together. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is adhered by the second adhesive member. A liquid crystal panel in which liquid crystal is sealed in a gap between the first substrate and the second substrate, which is formed by bonding a first substrate and a second substrate with a seal member at a predetermined interval; In a method for manufacturing a liquid crystal display device including a supporting substrate supporting
A step of adhering the central portion of the liquid crystal panel and the supporting substrate with a first adhesive member;
A step of adhering the outer peripheral portion outside the central portion of the liquid crystal panel and the support substrate with a second adhesive member having a curing shrinkage property;
A step of bending the liquid crystal panel so that the outer peripheral portion of the liquid crystal panel approaches the support substrate due to curing shrinkage of the second adhesive member;
A method for manufacturing a liquid crystal display device, comprising:   A portion excluding two corner portions facing each other across the central portion of the liquid crystal panel and the support substrate are bonded by the first adhesive member, and the two corner portions of the liquid crystal panel and the support substrate are joined together. The method for manufacturing a liquid crystal display device according to claim 3, wherein the second adhesive member is used for adhesion.

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