JP5109644B2 - Flexible wiring board mounting structure and liquid crystal display module using it. - Google Patents

Description

  The present invention relates to a mounting structure in which a flexible wiring board is folded and a liquid crystal display module to which the mounting structure is applied.

  FPD modules using liquid crystal display panels, organic electroluminescence display panels, and the like have recently been used as displays for mobile devices such as mobile phones and PDAs (Personal Digital Assistance) due to the advantage of thinning applied devices. ing. In this FPD module, a flexible wiring board (hereinafter referred to as FPC (Flexible Printed Circuit)) that is advantageous for thinning is used as a wiring board.

In a liquid crystal display module using an FPC, as disclosed in Patent Document 1, a mounting structure that is folded back to the back side of the liquid crystal display panel is employed in relation to a position with respect to an external circuit board to be electrically connected.
JP 2002-328391 A

  In recent years, the demand for miniaturization and thinning is extremely strict for displays of mobile devices, and further thinning is also demanded for FPD modules. For this reason, the radius of the bent portion at which the FPC is folded back to the back side of the display is also reduced, and accordingly, the springback action due to the elastic restoring force of the FPC itself is also increased.

  Conventionally, as a method for suppressing the spring back action, a method is adopted in which the folded-back portion of the FPC is fixed with an adhesive member such as a double-sided tape or is pressed down with an exterior case.

  In the case of the former fixing method using an adhesive member, the area and thickness of the adhesive member increase as the FPC bending radius decreases, which is disadvantageous for thinning, and workability, that is, repairability during repair / disassembly deteriorates.

  The latter method of pressing down with the outer case has a problem that warpage due to the spring back action of the FPC occurs in the outer case formed of a thin sheet metal or the like in order to promote thinning.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an FPC mounting structure that effectively suppresses a springback action caused by FPC folding and is excellent in repairability, and a liquid crystal display module using the same.

The FPC mounting structure according to claim 1 of the present invention is bent to the depth side in a state where one main surface formed across the width and depth is opposed to each other, and at least in a portion of the one main surface facing each other. A flexible wiring board provided with wirings formed to face each other and solder lands formed on at least one of the wirings of the one part facing each other, and a pair of terminal electrodes facing each other, A pair of jumper chips each having a passive element embedded therein, wherein the other terminal electrode is connected to the opposing wiring of the flexible wiring board, and between the pair of jumper chips A plurality of electronic chip components arranged in a row, and the pair of jumper chips includes one end side in the width direction of the flexible wiring board and And it is characterized in that it is formed respectively on the end side.

  The FPC mounting structure according to claim 2 is the FPC mounting structure according to claim 1, wherein the FPC mounting structure is installed at a position facing the solder land and the flexible wiring board on the other main surface of the flexible wiring board. It further has a pad which penetrates the flexible wiring board and is electrically connected to the solder land.

According to a third aspect of the present invention, there is provided a liquid crystal display module comprising: a liquid crystal display panel in which liquid crystal is sandwiched between a pair of substrates; and one end of the liquid crystal display panel is electrically connected to the liquid crystal display panel; The one main surface formed over the width and depth to the back side opposite to the viewing side of the display is bent to the depth side with the one main surface facing each other, and at least the one main surface facing each other is opposed to each other. And a flexible wiring board provided with a solder land formed on at least one of the wirings facing each other, a pair of terminal electrodes facing each other, and one terminal electrode There is soldered to the solder lands and the other terminal electrode connected to the wiring that faces of the flexible wiring board, a pair of passive elements are built Janpachi Has a flop, and a electronic chip component disposed between the pair of jumper chip, the pair of jumper chip are formed respectively at one end and the other end in the width direction of the flexible wiring board It is characterized by this.

A liquid crystal display module according to a fourth aspect of the invention is the liquid crystal display module according to the third aspect , wherein the other main surface of the flexible wiring board is installed at a position facing the solder land via the flexible wiring board. And a pad that penetrates the flexible wiring board and is electrically connected to the solder land.

The liquid crystal display module according to claim 5 further includes a shield case for storing the liquid crystal display panel in the liquid crystal display module according to claim 3 or 4 , and the folded flexible wiring board is shielded. It is characterized by extending along the inner surface of the case.

  ADVANTAGE OF THE INVENTION According to this invention, the springback effect | action accompanying folding | returning can be suppressed effectively, and the mounting structure of FPC excellent in the repair property, and a liquid crystal display module using the same can be provided.

  FIG. 1 is a schematic cross-sectional view showing a liquid crystal display module as an embodiment of the present invention, and FIGS. 2 and 3 show a state before the FPC is folded and a state after the folding, respectively, in the assembly process of the liquid crystal display module. Each perspective view and FIG. 4 are sectional views taken along the line IV-IV in the state of FIG.

  The casing of the present liquid crystal display module is formed by fitting a cover case 2 having the same shape from which the bottom plate is removed to a storage case 1 having a shape in which a top plate of a box having a flat rectangular parallelepiped shape is removed. Both cases 1 and 2 are formed by processing a thin metal plate such as a stainless steel plate. A display window 2b for observing the display is formed in the top plate 2a of the cover case 2.

  A frame 3 is disposed in the casing. The frame 3 according to the present embodiment includes a front chamber 3a and a rear chamber 3b, which are formed in a rectangular parallelepiped with a flat space outer shape, in two stages. That is, a step 3d is formed at the predetermined height position of the side plate 3c surrounding the space of the rectangular parallelepiped over the entire inner surface, and the front chamber 3a and the flat area are smaller by the area of the step 3d with the step 3d as a boundary. 3b is overlapped in two stages. The frame 3 is molded in a lump using a resin material.

In the front chamber 3a of the frame 3, the liquid crystal display panel 4 is accommodated with the peripheral edge supported by the step 3d. The liquid crystal display panel 4 has a pair of front and rear glass substrates 5 and 6 on which electrodes (not shown) are formed, and a predetermined gap is maintained by a frame-shaped sealing material (not shown) with the respective electrode formation surfaces facing each other. The liquid crystal (not shown) is sealed between the front and rear glass substrates 5 and 6 before and after being surrounded by a frame-shaped sealing material. A pair of front and rear polarizing plates 7 and 8 are attached to the outer surfaces of the front and rear glass substrates 5 and 6 opposite to the liquid crystal sealing side, respectively.

  The liquid crystal display panel 4 of this embodiment is an active matrix type liquid crystal display panel, and a single film-like counter electrode (not shown) is installed on the inner surface of the front glass substrate 5 on the viewing side of the display, and the other rear side. A plurality of pixel electrodes (not shown) are arranged in a matrix form on the inner surface of the glass substrate 6, and a display region is formed in which pixels formed on opposing portions of both electrodes are arranged in a matrix.

  Of the pair of front and rear glass substrates 5 and 6 in the liquid crystal display panel 4 of this example, one end surface of the rear glass substrate 6 is extended more appropriately than the corresponding end surface of the front glass substrate 5 to form a protruding portion 6a. ing. The protruding portion 6a of the rear glass substrate 6 is provided with a wiring circuit drawn from an electrode (not shown) and a connection terminal at each end thereof to form a driving circuit portion. The driving circuit portion includes a driving circuit element. A driver LSI 9 is mounted as COG (Chip On Glass). The FPC 10 is conductively joined to the input terminal area of the drive circuit unit.

In the rear chamber 3b of the frame 3, a side light type surface emitting irradiation panel 11 is accommodated and installed. Side light type surface emitting radiation panel 11 of the present embodiment, one end of the transparent light guide plate 12 forming the corresponding rectangle roughly the liquid crystal display panel 4 of the irradiation target, LED as a point light source (Light-Emitting Diode) In this example, two light guides 13 are arranged, and a light reflecting sheet 14 is installed on the rear surface 12b opposite to the front surface 12a opposed to the liquid crystal display panel 4 of the light guide plate 12. On the rear surface 12b where the light reflecting sheet 14 of the light guide plate 12 is installed, concentric uneven patterns (not shown) for uniformly reflecting the light emitted from the LEDs 13 and incident on the light guide plate 12 toward the front surface 12a. Is formed. Further, a light diffusion sheet 15 and a prism sheet 16 are laminated on the front surface 12a of the light guide plate to adjust the optical characteristics such as the luminance distribution and the emission direction of the irradiation light emitted in a planar shape from the light guide plate 12. .

In the surface-emitting radiation panel 11 of side light type which is configured as described above, light emitted from LED13 is incident from the end surface thereof facing the light guide plate 12, concentric unevenness of the incident light rear 12b The light enters the pattern, is internally reflected toward the front surface 12a, and is emitted in a planar shape from the front surface 12a. The planar emitted light is transmitted through the light diffusion sheet 15 and the prism sheet 16 so that the luminance distribution is made uniform, the emission direction is adjusted to the front direction, and the rear surface of the liquid crystal display panel 4 is irradiated. Note that there is also light that exits from the light guide plate 12 after entering the concentric pattern, but the emitted light is reflected by the light reflecting sheet 14 and reentered into the light guide plate 12. Thereby, the utilization efficiency of the emitted light from LED13 is raised significantly.

The FPC 10 that is conductively joined to the protruding portion 6 a of the substrate of the liquid crystal display panel 4 is drawn out of the frame 3 through a notch 3 e formed in the side plate 3 c of the frame 3, and is folded back to the back side of the frame 3. . FPC10 in this embodiment is of a single-sided mounting type wiring 10a (see FIG. 4) is formed on one surface 101, as shown in exploded perspective view in FIG. 2, on one side 101 which is a wiring forming surface The electronic chip components 17 such as a resistance element and a capacitor element are mounted on a COF (Chip On Film). A pair of jumper chips 18 and 18 are disposed at both ends of the row in which the electronic chip components 17 are arranged in parallel.

  As shown in the cross-sectional view of FIG. 4, the jumper chip 18 is provided with terminal portions 18d and 18e each having a U-shaped cross section of the electrodes 18b and 18c on a pair of opposed end surfaces of the substrate 18a. A capacitor element is formed with the other end portions of the electrodes 18b and 18c facing each other through a dielectric 18f, and a protective film 18g is deposited on the capacitor element portion. Of the two terminal portions 18 d and 18 e of each jumper chip 18, one terminal portion 18 e is conductively connected to the wiring 10 a of the FPC 10 by solder 19.

Further, as shown in FIG. 2, a pair of solder lands 10b and 10b are arranged on the FPC 10 side so as to correspond to the pair of jumper chips 18 and 18. Here, the position of each solder land 10b is set such that when the FPC 10 is folded back to the back side of the frame 3, the front end surface of each solder land 10b and the corresponding terminal portion 18d of the jumper chip 18 overlap. Yes. The electrode terminal portions 18 d and the solder lands 10b overlapped in a state of folding the FPC10 is conductively bonded by solder 20.

Pads 21 are disposed on the back side of the solder lands 10b with the FPC 10 interposed therebetween. The corresponding solder land 10b and the pad 21 are conductively connected by a through wiring 23 provided in a through hole 22 that penetrates the FPC 10. The pad 21 is a pad for bringing a soldering iron into contact when performing solder joining.

  Convex legs 3g are erected on the four corners of the outer surface of the frame bottom plate 3f. As shown in FIG. 1, the frame bottom plate 3f is accommodated with the outer surface of the frame bottom plate 3f by the height of the four convex legs 3g. A gap is secured between the inner surface of the case bottom plate 1a. A portion of the FPC 10 that is folded back to the back side of the frame 3 extends in the gap, and an end portion that is conductively connected to the external circuit board is drawn out of the storage case 1.

  As described above, the jumper chip 18 and the solder land 10b are arranged so as to be superposed on each opposing wiring forming surface of the FPC 10 bent at about 180 °, and the overlapping jumper chip 18 and the solder land 10b are soldered together. The spring back action of the folded FPC 10 can be reliably suppressed, and repair workability is improved as compared with the conventional method in which the spring back action is suppressed by an adhesive member such as a double-sided adhesive sheet.

  In addition, since the jumper chip 18 having a built-in capacitor element is used and the springback suppressing member and the passive element part are used together, the number of parts to be mounted on the FPC 10 is reduced, and the simplification of the module can be promoted.

  Next, the folding mounting operation of the FPC 10 in the manufacturing process of the liquid crystal display module of the present embodiment will be described with reference to FIGS.

  The assembly in which the liquid crystal display panel 4 in which the surface emitting irradiation panel 11 and the FPC 10 are conductively joined to the frame 3 is sequentially stored and installed is turned over as shown in FIG. 2, and from this state, the frame of the FPC 10 as shown in FIG. 3 The portion pulled out is folded back to the outer surface (back surface) side of the frame bottom plate 3f. At this time, the folding position is adjusted so that the corresponding jumper chip 18 and the solder land 10b overlap each other, and the pad 21 (provided on the back surface of the FPC 10 with the corresponding jumper chip 18 and the solder land 10b overlapping each other) ( A soldering iron is brought into contact with (see FIG. 4) and heated.

  Here, the pad 21 and the solder land 10 b are conductively connected by the through wiring 23. That is, the path from the pad 21 to the solder land 10b via the through wiring 23 is a good electrical conduction path in which conductors are connected, and the good electrical conduction path is also a good heat conduction path. Therefore, the heat of the soldering iron in contact with the pad 21 is efficiently conducted to the solder land 10b through the through wiring 23, and the solder 20 previously attached to the solder land is quickly melted, and the front end surface of the jumper chip 18 The solder land 10b is securely fused.

  In this way, when soldering the jumper chip 18 and the solder land 10b facing each other inside the folded FPC 10, the soldering iron is simply applied to the back-side pad 21 electrically connected to the solder land 10b via the through wiring 23. Since the pad 21 is exposed outside the folded FPC 10, the soldering of the jumper chip 18 and the solder land 10b, which is expected to be difficult because it is hidden inside the folded FPC 10, is very easily performed. can do.

  As described above, the liquid crystal display module to which the FPC mounting structure of the present embodiment is applied includes the jumper chip 18 and the solder land 10b provided in correspondence with the jumper chip 18 by the springback action of the FPC 10 folded back with a small radius. Since it is configured to suppress by soldering, the thickness of the outer case for suppressing the springback effect is avoided, and the repair workability is reduced because the adhesive member is not used to fix the folded FPC 10. I will not let you.

  Further, a pad 21 is provided on the back surface of the solder land 10b corresponding to the solder land 10b to be soldered to the jumper chip 18, and the pad 21 and the solder land 10b are electrically connected by the wiring 23 penetrating the FPC 10, so that the folded FPC 10 By simply applying a soldering iron to the pad 21 exposed to the outside, the jumper chip 18 and the solder land 10b that are hidden inside the folded FPC 10 can be easily soldered.

  As a result, it is possible to easily obtain an FPC mounting structure and a liquid crystal display module using the FPC mounting structure, which effectively suppresses the springback effect caused by the FPC folding and is excellent in repair.

In addition, this invention is not limited to said embodiment.
For example, the electronic component applied to the FPC mounting structure of the present invention is not limited to a jumper chip that incorporates passive elements, but may be a semiconductor chip that incorporates active elements such as driver chips, or a chip that simply conducts. It may be.

  In addition, the FPC mounting structure of the present invention is not limited to a single-sided FPC, but can be effectively applied to a double-sided FPC, and is not limited to a liquid crystal display module. The present invention can be widely applied to various electronic devices.

  In addition, the liquid crystal display module of the present invention is not limited to the type having a case for storing the folded FPC, but can be applied to a liquid crystal display module in which the FPC is exposed while being folded. Of course.

It is the typical sectional view showing the liquid crystal display module as one example of the present invention. It is a perspective view which shows the state before turning back FPC in the assembly process of the said liquid crystal display module. It is a perspective view which shows the state which turned up FPC in the assembly process of the said liquid crystal display module. It is the IV-IV sectional view taken on the line in the state of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Storage case 2 Cover case 3 Frame 3a Front chamber 3b Rear chamber 3c Side plate 3d Step 4 Liquid crystal display panel 5, 6 Front, rear glass substrate 7, 8 Front, rear polarizing plate 9 Driver LSI
10 FPC (Flexible Printed Circuit)
10a Wiring 10b Solder land 11 Surface emitting irradiation panel 12 Light guide plate 13 LED (Light-Emitting Diode)
14 Light reflection sheet 15 Light diffusion sheet 16 Prism sheet 17 Electronic chip component 18 Jumper chip 19, 20 Solder 21 Pad 22 Through hole 23 Through wiring

Claims (5)

A wiring formed on the depth side with one main surface formed across the width and depth facing each other, and at least one portion of the one main surface facing each other, and the one facing each other A flexible wiring board provided with a solder land formed on at least one of the wiring of the part to be
A pair of terminal electrodes facing each other is provided, one terminal electrode is solder-bonded to the solder land, and the other terminal electrode is connected to the facing wiring of the flexible wiring board , and a passive element is incorporated. A pair of jumper chips ;
A plurality of electronic chip components arranged in a row between the pair of jumper chips;
Have
The flexible wiring board mounting structure, wherein the pair of jumper chips are respectively formed on one end side and the other end side in the width direction of the flexible wiring board.   The pad according to claim 1, further comprising a pad that is installed at a position corresponding to the solder land on the other main surface of the flexible wiring board, and is connected to the solder land through the flexible wiring board. The mounting structure of the flexible wiring board of 1. A liquid crystal display panel in which liquid crystal is sandwiched between a pair of substrates;
One end is electrically connected to the liquid crystal display panel, and the one main surface formed across the width and depth to the back side opposite to the viewing side of the display of the liquid crystal display panel faces the depth side. A flexible wiring provided with a bent wiring formed so as to be opposed to each other on at least one of the main surfaces and a solder land formed on at least one of the wirings on the one facing each other A wiring board;
A pair of terminal electrodes facing each other is provided, one terminal electrode is solder-bonded to the solder land, and the other terminal electrode is connected to the facing wiring of the flexible wiring board , and a passive element is incorporated. A pair of jumper chips ;
An electronic chip component disposed between the pair of jumper chips;
Have
The pair of jumper chips are respectively formed on one end side and the other end side in the width direction of the flexible wiring board . The pad according to claim 1, further comprising a pad that is installed at a position corresponding to the solder land on the other main surface of the flexible wiring board, and is connected to the solder land through the flexible wiring board. 3. A liquid crystal display module according to 3 . A shield case for storing the liquid crystal display panel;
The liquid crystal display module according to claim 3 or claim 4, wherein the flexible wiring board is characterized in that extended along the inner surface of the shield case folded.

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