JP2005317760A - Wiring board and panel heater for liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a connection allowance current amount between a wiring board and an electrode by dispersing the arranging positions of conductive particles in the gap of a conductor and an electrode and increasing the number of connection contributing particles of the conductive particles. <P>SOLUTION: On a roughly center in the widthwise direction of the conductor 9, a plurality of center through-holes 11 for making ACF 14 flow in when crimping the conductor 9 with the electrode 5 are arranged at prescribed intervals in the longitudinal direction of the conductor 9 through a substrate 8 and the conductor 9. The inner diameter dimension W<SB>1</SB>in the widthwise direction of the conductor 9 in the center through-holes 11 is formed into the dimension of 1/4-1/2 of the width dimension W<SB>2</SB>of the conductor 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wiring board and a panel heater for liquid crystal display elements, and more particularly to a strip-shaped wiring board and a liquid crystal display element panel heater using the wiring board.

  Conventionally, in a liquid crystal display device having a liquid crystal display panel in which liquid crystal is sealed in a gap between a pair of substrates, a panel heater for a liquid crystal display element for heating the liquid crystal display panel in order to improve the response speed of the liquid crystal at a low temperature Is adopted.

  Such a panel heater for a liquid crystal display element is, for example, a transparent conductive material made of ITO (Indium Tin Oxide) or the like on almost the entire outer surface of one of the pair of substrates of the liquid crystal display panel. A film is provided.

  On the transparent conductive film, a pair of strip-shaped wiring boards are provided by crimping along opposite side edges of the transparent conductive film, and the portions of the transparent conductive film facing the wiring board are electrodes. The transparent conductive film is electrically connected to an external drive circuit of the liquid crystal display panel via the wiring board.

  This wiring board has a conductor made of copper foil or the like on one surface of a base made of polyimide or the like, for example, and is formed in a band shape having a constant width.

  And the electrode of the said transparent conductive film is electrically connected with the conductor of the wiring board through conductive adhesives, such as ACF containing several electroconductive particle.

  In order to connect the electrode and the wiring board in this panel heater for a liquid crystal display element, first, as shown in FIG. 8A, the ACF 23 is disposed on the electrode 22, and then the wiring board is placed so that the conductor 24 faces. 25 is placed. Then, by pressing the wiring board 25 toward the electrode 22 side, the conductive particles 26 of the ACF 23 interposed in the gap between the electrode 22 and the conductor 24 are compressed and crushed, and then the ACF 23 is cured. Thereby, the electrode 22 of the transparent conductive film 21 and the conductor 24 of the wiring board 25 are electrically connected by the conductive particles 26 crushed while being sandwiched between the electrode 22 and the conductor 24 (for example, , See Patent Document 1).

  However, in the conventional panel heater 28 for a liquid crystal display element, the wiring board 25 is formed in a strip shape, and when the wiring board 25 is pressed toward the electrode 22 when the electrode 22 and the conductor 24 are connected, FIG. ), The ACF 23 flows to both side edges of the wiring board 25 by the pressing force, and the conductive particles 26 move to both side edges of the wiring board 25 as the ACF 23 flows. It was easy to collect.

  For this reason, there is a possibility that the conductive particles 26 do not intervene in the central part in the width direction of the wiring board 25 in the gap between the electrode 22 and the conductor 24. In such a case, the central part in the width direction of the wiring board 25 This does not contribute to the electrical connection between the plate 25 and the electrode 22. Then, the allowable connection current between the wiring board 25 and the electrode 22 is limited. As a result, the liquid crystal display panel 29 may not be efficiently heated by the liquid crystal display element panel heater 28. Had a problem.

  Further, when the ACF 23 accumulates at both side edges of the wiring board 25 and the arrangement position thereof is biased, the conductive particles 26 are often not properly crushed between the conductor 24 and the electrode. In such a case, since the number of conductive particles 26 that contribute to electrical connection between the wiring board 25 and the electrode 22 (the number of connection contributing particles) is reduced, connection permission between the wiring board 25 and the electrode 22 is permitted. There was a risk that the current would be further limited.

JP 2002-023186 A

  The present invention has been made in view of these points, disperse the arrangement position of the conductive particles in the gap between the conductor and the electrode, and increase the number of particles that contribute to the connection of the conductive particles in the conductive adhesive, thereby, To provide a wiring board capable of improving the allowable connection current amount between a wiring board and an electrode, and a panel heater for a liquid crystal display element capable of efficiently heating a liquid crystal display panel using the wiring board. With the goal.

  In order to achieve the above object, the wiring board according to the first aspect of the present invention is characterized in that a conductor is provided on a base and the conductor is crimped to another electrode via a conductive adhesive. A plurality of central through holes for allowing the conductive adhesive material to flow into the substantially central portion in the width direction of the conductor when the conductor and the electrode are crimped to the base. The conductor is provided at a predetermined interval in the longitudinal direction of the conductor through the conductor, and the dimension in the width direction of the conductor in the central through hole is a dimension of 1/4 to 1/2 of the width dimension of the conductor. It is in the point formed.

  According to the first aspect of the present invention, since the plurality of central through holes are formed at a predetermined interval in the longitudinal direction of the conductor at the substantially central portion in the width direction of the conductor in the wiring board, At the time of crimping with the electrode, the conductive adhesive flows to both side edges of the wiring board, and also flows to the center in the width direction of the wiring board and flows into each through hole. Thereby, the flow direction of a conductive adhesive can be diversified. For this reason, the conductive particles contained in the conductive adhesive also move not only to the side edge portions but also to the central portion with the flow of the conductive adhesive, and are interposed in the gap between the conductor and the electrode. Arrangement positions can be dispersed.

  In addition, the surface area of the wiring board can be increased by the inner surface of the through-hole, thereby increasing the bonding area between the conductive adhesive and the wiring board, thereby improving the peel strength between the wiring board and the electrode. Can be planned.

  The wiring board according to the second aspect of the invention is characterized in that it is a side edge portion of the conductor and does not overlap with an arrangement position of the central through hole arranged in the longitudinal direction of the conductor. A side edge through hole penetrating the base body and the conductor is provided, and a dimension in the width direction of the conductor in the side edge through hole is less than or equal to ½ of a width dimension of the center through hole. It is in a formed point.

  According to the second aspect of the present invention, the side edge through-holes are formed at both side edges of the conductor, and the conductive adhesive flows into the side edge through-holes. The flow direction can be further diversified. Thereby, the arrangement positions of the conductive particles contained in the conductive adhesive can be further dispersed.

  Further, the surface area of the wiring board can be further increased by the inner surface of the side edge portion through-hole, thereby increasing the bonding area between the conductive adhesive and the wiring board. The strength can be further improved.

  Furthermore, the wiring board according to the invention described in claim 3 is characterized in that it is a side edge portion of the conductor and does not overlap with an arrangement position of the central through hole arranged in the longitudinal direction of the conductor. An opening for allowing the conductive adhesive to flow in when the conductor and the electrode are crimped is formed by cutting out the conductor.

  According to the third aspect of the present invention, the openings are formed by cutting out the conductors at both side edges of the conductor, and the conductive adhesive flows into each opening, so that the flow direction of the conductive adhesive is further increased. It is possible to diversify, whereby the arrangement positions of the conductive particles contained in the conductive adhesive can be further dispersed.

  In addition, the surface area of the wiring board can be increased by the opening, thereby increasing the bonding area between the conductive adhesive and the wiring board, thereby further improving the peel strength between the wiring board and the electrode. Can do.

  Furthermore, the panel heater for a liquid crystal display element according to the invention of claim 4 is characterized in that the conductor provided on the base of the belt-like wiring board is electrically connected to the conductive film provided on the substrate via the conductive adhesive. In a panel heater for a liquid crystal display element that heats the conductive film by applying a voltage to the conductive film by the conductor and heats the liquid crystal display panel, a substantially central portion in the width direction of the conductor In addition, a plurality of central through holes for allowing the conductive adhesive to flow in when the conductor and the conductive film are pressed are arranged at predetermined intervals in the longitudinal direction of the conductor through the base and the conductor. It is provided that the dimension in the width direction of the conductor in the central through hole is formed to be 1/4 to 1/2 of the width dimension of the conductor.

  According to the fourth aspect of the present invention, since the plurality of central through holes are formed at a predetermined interval in the longitudinal direction of the conductor at substantially the central portion in the width direction of the conductor in the wiring board, At the time of pressure bonding with the film, the conductive adhesive flows to both side edges of the wiring board and also flows to the central part in the width direction of the wiring board and flows into the respective through holes in the central part. Thereby, the flow direction of a conductive adhesive can be diversified. For this reason, the conductive particles contained in the conductive adhesive also move not only to the side edge portions but also to the central portion with the flow of the conductive adhesive, and are interposed in the gap between the conductor and the conductive film. Arrangement positions can be dispersed.

  As described above, according to the wiring board according to each of the present invention, since the conductive particles can be dispersed and arranged in the gap between the conductor and the electrode, the conductive particles are made conductive by the pressing force to the wiring board. Can be properly crushed in the gap between the electrode and the electrode. Thereby, the connection contribution particle number of the conductive particles in the conductive adhesive can be increased, and the connection allowable current amount between the wiring board and the electrode can be improved.

  Furthermore, by providing the side edge portion through-holes, it is possible to further diversify the flow direction of the conductive adhesive, disperse the arrangement positions of the conductive particles, and improve the allowable connection current amount.

  In addition, by providing the opening in the side edge portion of the conductor, the flow direction of the conductive adhesive can be diversified, and the arrangement positions of the conductive particles can be dispersed to improve the allowable connection current amount.

  Moreover, according to the wiring board according to the present invention, the surface area of the wiring board can be increased by the inner surface of the central through hole, the inner surface of the side edge through hole, and the end face of the opening. Since the bonding area between the adhesive and the wiring board can be increased, the peel strength between the wiring board and the electrode can be improved.

  Furthermore, according to the panel heater for a liquid crystal display element according to the present invention, the connection allowable current amount can be improved by dispersing the arrangement position of the conductive particles in the gap between the conductor and the conductive film. The liquid crystal display panel can be efficiently heated by the liquid crystal display element panel heater using the wiring board.

  Hereinafter, embodiments of a panel heater for a liquid crystal display element using a wiring board according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic plan view showing a main part of the panel heater for a liquid crystal display element according to the present embodiment, and FIG. 2 is a schematic cross-sectional view taken along line AA showing the panel heater for the liquid crystal display element of FIG. .

  As shown in FIGS. 1 and 2, the panel heater 1 for a liquid crystal display element is disposed outside one glass substrate of a pair of glass substrates included in the liquid crystal display panel 2, and is almost on the surface of the glass substrate 3. A transparent conductive film 4 made of ITO or the like is provided on the entire surface.

  On the transparent conductive film 4, a flexible wiring board 7 as a pair of strip-shaped wiring boards is provided by crimping along both opposite side edges of the transparent conductive film 4. A portion of the transparent conductive film 4 facing the flexible wiring board 7 is an electrode 5 of the transparent conductive film 4.

  The flexible wiring board 7 has a flexible band-shaped substrate 8 made of polyimide or the like, and a conductor 9 made of copper foil or the like is provided on one surface of the substrate 8. The conductor 9 is electrically connected to an external drive circuit (not shown) of the liquid crystal display panel 2. And the flexible wiring board 7 is formed in the strip | belt shape of the length dimension and the width dimension of the grade which the conductor 9 respond | corresponds to the said electrode 5 as a whole. FIG. 1 is a view in which the conductor 9 (shown by a dotted line) is viewed through the substrate 8 from the substrate 8 side.

  In the flexible wiring board 7, a plurality of circular central through holes 11 penetrating the base body 8 and the conductor 9 are arranged in a central portion in the width direction of the conductor 9 at a predetermined interval in a line in the longitudinal direction of the flexible wiring board 7. Are arranged and arranged. In addition, the shape of each center part through-hole 11 is not limited to circular shape, For example, a rhombus shape etc. may be sufficient. Further, the arrangement position of each central portion through hole 11 may be substantially the central portion in the width direction of the conductor 9.

The inner diameter dimension W _{1 in} the width direction of the conductor 9 in each central through hole 11 is formed to be ¼ to ½ of the width dimension W ₂ of the conductor 9.

  And the flexible wiring board 7 is arrange | positioned so that the conductor 9 of the flexible wiring board 7 may oppose the electrode 5 of the transparent conductive film 4 through ACF14 as a conductive adhesive containing the conductive particles 13. Specifically, a plurality of conductive particles 13 are interposed in the gap between the conductor 9 and each electrode 5, and ACF 14 flows into each central through-hole 11. Thereby, the transparent conductive film 4 and the flexible wiring board 7 are electrically connected, and the transparent conductive film 4 is electrically connected to the external drive circuit via the flexible wiring board 7.

  Next, the operation of this embodiment will be described.

  First, as shown in FIG. 3A, the ACF 14 is disposed on the electrode 5 of the transparent conductive film 4, and the flexible wiring board 7 is placed so that the electrode 5 and the conductor 9 face each other. 7 base 8 is pressed to the electrode 5 side.

  Then, as shown in FIG. 3 (b), the ACF 14 flows to both side edges of the wiring board in the gap between the conductor 9 and the electrode 5 by the pressing force, and at the center through hole 11 side, that is, the conductor 9 It flows to the center part in the width direction and flows into each center part through-hole 11. At this time, the conductive particles 13 contained in the ACF 14 also move to the both side edge portions and the central portion as the ACF 14 flows, and are interposed in the gap between the conductor 9 and the electrode 5.

  Then, the ACF 14 is cured after the conductive particles 13 of the ACF 14 interposed between the electrode 5 and the conductor 9 are compressed and crushed by the pressing force. Thereby, the electrode 5 of the transparent conductive film 4 and the conductor 9 of the wiring board are electrically connected by the conductive particles 13 crushed while being sandwiched between the electrode 5 and the conductor 9.

  According to this embodiment, since each central part through-hole 11 is formed in the center part of the width direction of the conductor 9 in the flexible wiring board 7, when the conductor 9 and the electrode 5 are pressure-bonded, the ACF 14 is a flexible wiring. While flowing to both side edges of the board 7, it also flows to the center part in the width direction of the wiring board and flows into the respective center part through holes 11. Since the flow direction of the ACF 14 is diversified in this way, the conductive particles 13 contained in the ACF 14 move not only to the both side edge portions but also to the central portion as the ACF 14 flows, and the conductor 9 and each electrode 5, the arrangement positions of the conductive particles 13 are dispersed.

  Therefore, by using the flexible wiring board 7, the conductive particles 13 can be dispersed and arranged in the gap between the conductor 9 and the electrode 5, and the conductive particles 13 are connected to the conductor 9 by the pressing force to the flexible wiring board 7. It can be properly crushed in the gap with the electrode 5. Thereby, the connection contribution particle number of the conductive particles 13 in the ACF 14 can be increased, and the allowable connection current amount between the flexible wiring board 7 and the transparent conductive film 4 can be improved. As a result, the liquid crystal display panel 2 can be efficiently heated by the liquid crystal display element panel heater using the flexible wiring board 7.

  Further, by forming each central through hole 11 through the conductor 9 and the substrate 8, the surface area of the flexible wiring board 7 can be increased by the inner surface of each central through hole 11. Thereby, since the adhesion area of ACF14 and the flexible wiring board 7 can be enlarged, the peeling strength of the flexible wiring board 7 and the electrode 5 of the transparent conductive film 4 can be improved.

  Next, a second embodiment of the wiring board according to the present invention will be described with reference to FIGS. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and demonstrated.

  As shown in FIG. 4, the flexible wiring board 7 as the wiring board according to the second embodiment has a flexible central portion through hole 11 that penetrates the base body 8 and the conductor 9 in the central portion in the width direction of the conductor 9. The wiring boards 7 are arranged in a line in the longitudinal direction at predetermined intervals.

  A plurality of penetrating the base body 8 and the conductor 9 are located at both side edges of the conductor 9 in the flexible wiring board 7 and at positions where they do not overlap with the arrangement positions of the central through holes 11 arranged in the longitudinal direction of the conductor 9. Side edge through-holes 16 are provided. In 2nd Embodiment, each side edge part through-hole 16 is arrange | positioned 1 each about the both-sides edge part between each center part through-hole 11 in the said longitudinal direction.

The inner diameter dimension W _{3 in} the width direction of the conductor 9 in each side edge portion through hole 16 is formed to have a size of ½ or less of the width dimension W ₁ of the central portion through hole 11. Thus, the two side edge part through-holes 16 may be provided so as to face both side edges in the width direction of the conductor 9. Therefore, in this embodiment, the inner diameter dimension W ₃ of the side edge portion through-hole 16 is formed to be shorter than the inner diameter dimension W ₁ of the central portion through-hole 11.

  For example, as shown in FIG. 5, the side edge portion through-holes 16 are formed between the respective center edge through-holes 11 arranged in the longitudinal direction of the flexible wiring board 7. You may arrange | position 2 each about the both sides edge part of 9.

  According to the present embodiment, each central through hole 11 is formed in the central portion of the flexible wiring board 7 in the width direction of the conductor 9, and each side edge through hole 16 is formed in both side edges of the conductor 9. As a result, the ACF 14 flows to the central portion in the width direction of the flexible wiring board 7 and flows into the central through holes 11, and flows to both side edges to form the side edge through holes 16. It also flows inside. Thereby, since the flow direction of ACF14 can be diversified more, the arrangement position of the electroconductive particle 13 contained in ACF14 can be disperse | distributed more.

  Therefore, the number of connection-contributing particles of the conductive particles 13 in the ACF 14 can be further increased, and the allowable connection current amount between the flexible wiring board 7 and the transparent conductive film 4 can be further improved.

  Further, by forming each side edge through hole 16 penetrating the conductor 9 and the base 8 at both side edges of the conductor 9, the surface area of the flexible wiring board 7 is increased by the inner surface of each side edge through hole 16. be able to. Thereby, since the adhesion area of ACF14 and the flexible wiring board 7 can be enlarged, the peeling strength of the flexible wiring board 7 and the electrode 5 can be improved.

  Subsequently, a third embodiment of the wiring board according to the present invention will be described with reference to FIGS. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and demonstrated.

  As shown in FIG. 6, the flexible wiring board 7 as the wiring board according to the third embodiment has a plurality of central through holes 11 that penetrate the base body 8 and the conductor 9 in the central part in the width direction of the conductor 9. The flexible wiring board 7 is arranged in a line at a predetermined interval in the longitudinal direction.

  The opening 18 connects the conductor 9 in the width direction at a position on both sides of the conductor 9 in the flexible wiring board 7 and at a position that does not overlap with the arrangement position of each central through hole 11 aligned in the longitudinal direction of the conductor 9. It is cut out in a rectangular shape toward the center. In the present embodiment, one opening 18 is provided on each side edge between the central through-holes 11 arranged in the longitudinal direction of the conductor 9, whereby the conductor 9 is shaped like a fish bone. It is formed into a shape.

Further, in the present embodiment, each opening 18 and each central through hole 11 is arranged with respect to the notch dimension W ₄ of each opening 18 and the inner diameter W ₁ of each central through hole 11. The cross-sectional area in the width direction (BB cross section) of the conductor 9 at the installation position may be larger than the cross-sectional area in the width direction (CC cross section) of the conductor 9 at the position where each opening 18 is formed. .

  Each opening 18 may not be formed in a rectangular shape toward the center in the width direction of the conductor 9 as described above. For example, as shown in FIG. 7, each opening 18 may be cut out in a semicircular shape toward the center.

  According to the present embodiment, a plurality of central portion through holes 11 are formed in the central portion of the conductor 9 in the width direction of the flexible wiring board 7, and a plurality of openings 18 are formed on both side edges of the conductor 9. Since it is formed by cutting out the conductor, the ACF 14 flows toward the central portion in the width direction of the flexible wiring board 7 and flows into the respective through holes 11 at the central portion, and flows to both side edge portions. It also flows into each opening 18. Thereby, since the flow direction of ACF14 can be diversified more, the arrangement position of the electroconductive particle 13 contained in ACF14 can be disperse | distributed more.

  Therefore, the number of particles contributing to the connection of the conductive particles 13 can be further increased, and the amount of allowable connection current between the flexible wiring board 7 and the transparent conductive film 4 can be further improved.

  Moreover, the surface area of the end surface of the conductor 9 can be increased by cutting out the both side edges of the conductor 9 to form the opening 18. Thereby, since the adhesion area of ACF14 and the conductor 9 can be enlarged, the peeling strength of the flexible wiring board 7 and the electrode 5 can be aimed at.

  The present invention is not limited to the above-described embodiments, and various modifications can be made as necessary.

  Subsequently, the connection allowable current amount between the wiring board and the transparent conductive film will be described by comparing the liquid crystal display element panel heater according to the present invention with a conventional liquid crystal display element panel heater.

  In each of the following examples and comparative examples, a wiring board having a conductor made of a copper foil having a width dimension of 6 mm, a length dimension of 260 mm, and a thickness of 0.035 mm is used as the present invention and the conventional wiring board. Using.

  Further, as the wiring board of the first embodiment of the present invention, a plurality of central through holes having an inner diameter of 3 mm, that is, an inner diameter of 1/2 of the width of the conductor, are provided in the center of the conductor of the wiring board in the width direction. A wiring board formed by aligning and arranging at a predetermined interval in the longitudinal direction of the wiring board was used.

  Further, as a wiring board according to the second embodiment of the present invention, a plurality of central portion penetrations having an inner diameter of 2 mm, that is, an inner diameter of 1/3 of the width of the conductor, are provided in the center in the width direction of the conductor of the wiring board A wiring board was used in which the holes were aligned and arranged with a predetermined gap in the longitudinal direction of the wiring board.

  Further, as the wiring board of the third embodiment of the present invention, a plurality of central portions having an inner diameter dimension of 1.5 mm, that is, an inner diameter dimension of 1/4 of the width dimension of the conductor, in the central portion in the width direction of the conductor of the wiring board. A wiring board in which through-holes were formed in a line with a predetermined gap in the longitudinal direction of the wiring board was used.

  Here, in a conductor made of a copper foil having a thickness of 0.035 mm, a conductor allowable current per 1 mm width is set to 2.2 A / mm.

Using the ACF having a current density α of 0.01 A / mm ² for the wiring boards of these comparative examples, the first example, the second example, and the third example, the transparent conductive film in the panel heater for liquid crystal display elements was used. Connected to the electrode.

In the liquid crystal display device panel heater using the conventional wiring board as a comparative example, since the conductor width of the wiring board is a 6 mm, conductor permissible current I ₀ is
I ₀ = 6 mm × 2.2 A / mm = 13.2 A.

  However, when the wiring board of the comparative example is pressure-bonded to the electrode of the transparent conductive film of the panel heater for a liquid crystal display element, the conductive particles of ACF arranged between the conductors flow to both side edges of the wiring board. For this reason, the conductive particles are not arranged in the central portion (1/2 (3 mm) of the conductor width dimension) in the width direction of the conductor, and the region does not contribute to the electrical connection between the conductor and the electrode. .

  In addition, since the ACF has accumulated on both side edges of the wiring board, and the conductive particles could not be properly crushed between the conductor and the electrode, the both side edges of the conductor on which the conductive particles are disposed substantially Only 2/3 (1 mm) of each (1/4 (1.5 mm) of the conductor width dimension) was an effective width (connection effective width) for electrical connection between the conductor and the electrode.

For this reason, the area (connection effective area) S ₀ effective for electrical connection between the conductor and the electrode when the wiring board of the comparative example is used is:
S ₀ = 1 mm × 2 × 260 mm = 520 mm ²
The allowable connection current I ₀₁ is
I ₀₁ = 520 mm ² × 0.01 A / mm ² = 5.2 A.

On the other hand, in the panel heater for a liquid crystal display element using the wiring board of the first embodiment, since a plurality of central through holes having an inner diameter of 3 mm are formed in the wiring board, the allowable conductor current I ₁ is
I ₁ = 1.5 mm × 2 × 2.2 A / mm = 6.6 A.

  However, when the circuit board of the first embodiment is pressure-bonded to the transparent conductive film, since the ACF flows into the central through hole, the flow direction of the ACF is diversified, so the conductive particles are arranged in the gap between the conductor and the electrode. The positions were dispersed throughout, and the effective connection width was 1.5 mm × 2 = 3 mm.

For this reason, the effective connection area S ₁ when using the wiring board of the first embodiment is
S ₁ = 3 mm × 260 mm = 780 mm ²
The allowable connection current I ₁₁ is
I ₁₁ = 780 mm ² × 0.01 A / mm 2 = 7.8 A.

In the liquid crystal display device panel heater using the wiring board of the second embodiment, since the central portion through hole of the inner diameter 2mm in the wiring board is formed with a plurality, conductors permissible current I ₂ is
I ₂ = 2 mm × 2 × 2.2 A / mm = 8.8 A.

  However, in the second embodiment as well, since the flow direction of the ACF is diversified when the wiring board and the transparent conductive film are crimped, the arrangement positions of the conductive particles are dispersed throughout the gap between the conductor and the electrode, and the connection is effective. The width was 2 mm × 2 = 4 mm.

Therefore, connection effective area S ₂ in the case of using the circuit board of the second embodiment,
S ₂ = 4 mm × 260 mm = 1024 mm ²
The allowable connection current I ₂₁ is
I ₂₁ = 1024 mm ² × 0.01 A / mm 2 = 10.2 A.

Furthermore, in the panel heater for a liquid crystal display element using the wiring board of the third embodiment, since a plurality of central through holes having an inner diameter of 1.5 mm are formed in the wiring board, the conductor allowable current I ₃ is
I ₃ was 2.25 mm × 2 × 2.2 A / mm = 9.9 A.

  However, in the third embodiment as well, since the flow direction of the ACF is diversified when the wiring board and the transparent conductive film are crimped, the arrangement positions of the conductive particles are dispersed throughout the gap between the conductor and the electrode, and the connection is effective. The width was 2.25 mm × 2 = 4.5 mm.

For this reason, the effective connection area S ₃ when the wiring board of Example 2 is used is
S ₃ = 4.5 mm × 260 mm = 1170 mm ²
The allowable connection current I ₃₁ is
I ₃₁ = 1170 mm ² × 0.01 A / mm 2 = 11.7 A.

  From this result, the substantial allowable current is 1.27 times that of the first embodiment, 1.69 times that of the second embodiment, 1.69 times that of the second embodiment, and the third. The allowable current of the example was 1.9 times, and it was found that the allowable current amount was improved in each of the examples.

Typical top view which shows the principal part of the panel heater for liquid crystal display elements which concerns on this invention Typical sectional drawing in AA which shows the panel heater for liquid crystal display elements of FIG. (A) is a schematic diagram showing before the circuit board is crimped in the panel heater for the liquid crystal display element of FIG. 1, and (b) is a schematic diagram showing after the circuit board is crimped. Typical top view which shows other embodiment of the wiring board which concerns on this invention. Typical top view which shows other embodiment of the wiring board which concerns on this invention. Typical top view which shows other embodiment of the wiring board which concerns on this invention. Typical top view which shows other embodiment of the wiring board which concerns on this invention. (A) is a schematic diagram showing before crimping of a wiring board in a conventional panel heater for liquid crystal display elements, and (b) is a schematic diagram showing after crimping of a wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Panel heater for liquid crystal display elements 2 Liquid crystal display panel 3 Glass substrate 4 Transparent conductive film 5 Electrode 7 Flexible wiring board 8 Base | substrate 9 Conductor 11 Center part through-hole 13 Conductive particle 14 ACF
W ₁ Inner diameter of central through hole W ₂ Width of conductor

Claims (4)

In a strip-shaped wiring board in which a conductor is provided on a base and the conductor is electrically connected by being crimped to another electrode via a conductive adhesive,
A plurality of central through holes for allowing the conductive adhesive to flow when the conductor and the electrode are crimped substantially through the center in the width direction of the conductor pass through the base body and the conductor. The conductors are arranged side by side at a predetermined interval in the longitudinal direction, and the dimension in the width direction of the conductor in the central through hole is formed to be 1/4 to 1/2 of the width dimension of the conductor. Wiring board.   Side edge through holes penetrating the base and the conductor are provided at positions that are side edges of the conductor and do not overlap with the arrangement positions of the central through holes arranged in the longitudinal direction of the conductor. The wiring board according to claim 1, wherein a dimension in the width direction of the conductor in the side edge part through hole is formed to be a dimension of ½ or less of a width dimension of the central part through hole.   The conductive adhesive is caused to flow into a side edge of the conductor at a position that does not overlap with a position where the central through hole arranged in the longitudinal direction of the conductor is overlapped. The wiring board according to claim 1, wherein an opening is formed by cutting out the conductor. A conductor provided on a base of a belt-like wiring board is electrically connected to a conductive film provided on a substrate via a conductive adhesive, and a voltage is applied to the conductive film by the conductor, whereby the conductive film is provided. In a panel heater for a liquid crystal display element that heats the liquid crystal display panel by
A plurality of central through holes for allowing the conductive adhesive material to flow into the conductor in the width direction of the conductor when the conductor and the conductive film are crimped pass through the base and the conductor. Are arranged at predetermined intervals in the longitudinal direction, and the width direction dimension of the conductor in the central through hole is formed to be 1/4 to 1/2 of the width dimension of the conductor. Panel heater for liquid crystal display elements.