JP2016045991A - Fpc and surface light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FPC in which crack is hardly formed and connection failure due to disconnection is hardly generated in a case where stress is applied to an FPC terminal part when the FPC is inserted into and removed from a connector for the FPC, and also to provide a surface light source.SOLUTION: In a wiring part 42 which is a terminal part 43 of an FPC 4 and located in the vicinity of a terminal part 441 of a reinforcement member 44, a stress concentration part 45 is formed which changes the width of the wiring part 42. The stress concentration part 45 has the wiring part 42 away from the terminal part 441 of the reinforcement member 44 by a predetermined distance as a starting point and is used as a notch which reduces the width of the wiring part 42 of the FPC 4 where the reinforcement member 44 is not arranged.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an FPC and a planar light source device using the FPC.

  Since liquid crystal display devices, signboards, guide lights, and the like are not self-luminous display devices that emit light from the display unit itself, a planar light source device that illuminates the display unit is required. As the planar light source device, there are a side light type (also called an edge light type) and a direct type. The side light type planar light source device is a device in which a light source is disposed on a side surface portion of a casing, and the direct type planar light source device is disposed on a rear surface side of a housing in which a light source is opposed to a liquid crystal display unit. Is.

  Some side-ride type planar light source devices use a light guide plate to guide light from a light source in a desired direction. A planar light source device using a light guide plate is a linear light source diode (Light Emitting Diode: hereinafter referred to as LED) and other light sources arranged in a line on a flexible substrate (Flexible Printed Circuit Board: hereinafter referred to as FPC). Is used. The FPC is composed of a wiring portion provided with a wiring pattern for supplying power to each point light source such as an LED, and a terminal portion at the end of the wiring portion, and the terminal portion is mounted on another electronic circuit board. By being incorporated in the FPC connector, the FPC wiring portion and the FPC connector are connected, and power is supplied to each point light source.

  In a planar light source device equipped with an FPC, when a connection failure occurs between the FPC and an FPC connector mounted on another electronic circuit board, power is not stably supplied to the point light source, causing a lighting failure. There is a case.

  The FPC used in the display device disclosed in Patent Document 1 is a protrusion, notch, or mark that serves as a mark for visually confirming the degree of insertion of the FPC terminal when inserted into and connected to an FPC connector. Is provided. Thus, a technique for detecting a connection failure between the FPC and the FPC connector is disclosed.

JP 2003-316283 A

  According to the configuration disclosed in Patent Document 1, notches, protrusions, and the like serving as marks are provided on the terminal portion of the FPC, and when the FPC connector is inserted and connected, the FPC terminal portion is bent by mistake. Even if it is closed, cracks are likely to occur. In particular, when a reinforcing member is provided in a portion to be inserted into the connector of the FPC terminal portion, stress is generated in the region around the formation portion of the mark of the FPC terminal portion due to the difference in rigidity between the FPC and the reinforcing member. There was a problem that cracks were likely to occur in the part.

  The present invention was made to solve the above problems, and even when the FPC terminal part is mistakenly bent when the FPC is inserted into and removed from the FPC connector, the FPC is hardly cracked. An object of the present invention is to provide an FPC and a planar light source device in which poor connection due to disconnection hardly occurs.

  The FPC of the present invention and the planar light source device including the FPC include a terminal part connected to the connector and a wiring part formed to supply power or a signal through the connector, The FPC is provided with a reinforcing member on the non-connecting surface among the connecting surface of the connector and the non-connecting surface arranged opposite to the connecting surface, and is provided from the end of the reinforcing member. A stress concentration part for changing the width of the wiring part is formed on the wiring part at a distance.

  In the FPC according to the configuration of the present invention and the planar light source device including the FPC, when the terminal portion of the FPC is inserted into and removed from the FPC connector, the FPC is hardly cracked and connection failure due to disconnection can be prevented.

It is a disassembled perspective view which concerns on the display apparatus of this invention. It is a whole perspective view of FPC used for the display apparatus of this invention. It is a principal part enlarged view of the connector and FPC in the display apparatus of this invention. It is a principal part enlarged view of the connector and FPC in the display apparatus of this invention.

  Embodiment 1 of the present invention will be described below with reference to the drawings. 1 is an exploded perspective view according to the display device of the present invention, FIG. 2 is an overall perspective view of the FPC, and FIG. 3 is a main part in a state where the FPC is inserted into the FPC connector according to the display device of the present invention. FIG. 3A is an enlarged view, FIG. 3A is a front view, and FIG. 3B is a side view.

<Overall configuration>
As shown in FIG. 1, the display device 10 of the present invention includes a display panel 1 and a planar light source device 2 for irradiating the display panel 1. The planar light source device 2 accommodates optical members such as an FPC 4 having a light source 41 such as an LED, a reflection sheet 22, a light guide plate 23, and an optical sheet 24 in a lower frame 21 having a side surface and a bottom surface, and includes an opening. The holding frame 25 holds these optical members from the exit surface side of the planar light source device 2. Further, the display panel 1 is disposed on the exit surface side of the planar light source device 2 and above the holding frame 25, and the lower frame 21 and the upper frame 3 that holds the display panel 1 from the display surface side are engaged. Thus, the display device 10 is configured.

  As shown in FIGS. 2 and 3, the FPC 4 includes a plurality of point light sources 41 such as LEDs, and wiring patterns 421 for supplying power to the light sources 41 are provided in the wiring part 42. A terminal portion 43 connected to the connector 6 formed on another electronic circuit board or the like is formed on the terminal formed extending to the wiring portion 42. In the planar light source device 2 according to the present embodiment, as shown in FIG. 1, an FPC connector is formed on the back surface of the lower frame 21 on the opposite side to the display surface of the display device 10, and FIG. As shown, the terminal portion 43 of the FPC 4 is connected to the connector 6. The terminal portion 43 is connected to a connector 6 formed on another electronic circuit board or the like and supplies power.

  The inside of the connector 6 is configured to have a shape corresponding to the terminal portion 43. By incorporating the inside of the terminal portion 43 into the connector 6, the terminal portion 43 of the connector 6 is connected to the wiring pattern 421 of the FPC 4, and power is supplied to each light source 41. Supply. The FPC 4 is detachably assembled to the connector 6 and supplies power to the light source 41 such as an LED via the wiring pattern 421 of the FPC 4. The surface of the terminal portion 43 of the FPC 4, that is, the connection surface with the connector 6 is exposed to a wiring pattern made of copper or copper alloy, and the surface is used for the purpose of preventing corrosion of the wiring pattern 421 or reducing the electrical contact resistance value. In addition, a thin metal plating 431 may be applied after nickel alloy plating such as nickel-phosphorus alloy or nickel-boron alloy.

  In addition, when a metal plating 431 of a nickel alloy having a high hardness is applied on the connection surface of the terminal portion 43 on a flexible copper or copper alloy, if the terminal portion 43 is bent, a minute crack is likely to occur, and the crack is large. May crack up to the copper wiring pattern. For this reason, the reinforcing member 44 using a material such as polyimide resin having high rigidity is arranged so as to protect the terminal portion 43 so that the wiring pattern of the terminal portion 43 is not bent. In addition, the reinforcing member 44 extends to a non-connection surface opposite to the connection surface on which the metal plating 431 of the terminal portion 43 is applied, to the outside from the region where the metal plating 431 is formed (see FIG. 3B). It arrange | positions so that the terminal part 43 may be reinforced. Moreover, in order to prevent the terminal part 43 from moving after insertion of the connector 6, there may be a case where a protruding part 432 protruding outward is provided.

<FPC insertion process>
FIG. 4 is an enlarged view (side view) of a main part of the connector and the FPC. The process of inserting the terminal portion 43 of the FPC 4 into the connector 6 will be described with reference to FIG. As shown in FIG. 4, the connector 6 includes an insertion port 61 for inserting the FPC 4 and a lock mechanism 62 such as an actuator for connecting the connector 6 and the FPC 4. The FPC 4 inserts the terminal portion 43 from the connector insertion port 61. When inserting the FPC 4 into the connector 6, the terminal portion 43 of the FPC 4 is inserted into the insertion opening 61 of the connector 6 from an oblique direction, and the FPC 4 is horizontally placed along the facing surface in the connector 6 where the terminal portion 43 is disposed. Move. After confirming that the terminal portion 43 of the FPC 4 is disposed at a desired position of the connector 6, the lock mechanism 62 such as an actuator is operated to connect the FPC 4 to the connector 6. This prevents the FPC 4 from coming off. Further, when the FPC 4 is pulled out from the connector 6, the lock mechanism 62 is released and the FPC 4 is pulled out from the connector 6 in the reverse order of this work order.

  The lock mechanism 62 such as an actuator is a connector 6 that can be connected by a flip lock (rotation one-touch type) and enables the FPC 4 to be connected with a simple and light force. When the FPC 4 is inserted into the connector 6, the FPC 4 terminal portion 43 is inserted into the connector 6 from obliquely above (FIG. 4). Further, the FPC protrusion 432 is inserted so as to be accommodated in a recess formed in the connector (FIG. 3A). After the insertion, the FPC 4 is pulled lightly in the horizontal direction to confirm that the FPC 4 is held in the positioning portion, and then the actuator lock 62 is pushed down to lock (FIG. 3B). When the insertion of the FPC 4 into the connector 6 is insufficient, or when there is an extreme insertion shift, the lock function 62 of the actuator is poorly hung up. In this case, it is necessary to remove the FPC 4 from the connector 6 and insert it again.

  The thickness of the FPC that is generally used for FPC connectors is as thin as 0.3 mm, and the thickness of the reinforcing member 44 is about 0.1 to 0.2 mm. Further, as described above, the terminal portion 43 is inserted into the connector 6 and is provided with a protruding portion 432 for the purpose of preventing the connector 43 from coming off after assembly or being displaced, and is fitted to the connector 6 side at a position corresponding to the protruding portion 432. The FPC terminal portion 43 is fitted into the recess to be performed. When the operator repeatedly inserts and removes the FPC 4, it is necessary to work so as not to bend or twist the portion of the terminal portion 43 of the FPC 4, but when the FPC 4 is inserted or removed, the terminal An excessive bending force or twisting force may be applied to the portion 43, causing a micro crack in the metal plating layer 431 of the terminal portion 43, which may lead to a contact failure.

  Therefore, as shown in FIG. 3A, the FPC used in the planar light source device of the present invention is connected to the terminal portion 43 of the FPC 4 and the wiring portion 42 that is separated from the terminal portion 441 of the reinforcing member 44 by a predetermined position. A stress concentration portion 45 that changes the width of the wiring portion 42 is formed. The stress concentration portion 45 is a notch portion that continuously decreases the width of the wiring portion 42 of the FPC 4 where the reinforcing member 44 is not disposed, starting from the wiring portion 42 that is a predetermined position away from the terminal portion 441 of the reinforcing member 44.

(Function)
By forming the stress concentration part 45 in the wiring part 42 of the FPC 4, the difference in bending rigidity between the terminal part 43 where the reinforcing member 44 is disposed and the wiring part 42 of the FPC 4 whose width has changed is increased. That is, the stress due to the bending rigidity difference can be concentrated on the stress concentration portion 45. Therefore, it is possible to prevent stress such as bending force and torsional force from being applied to the terminal portion 43 by the stress concentration portion 45 formed in the wiring portion 42 of the FPC 4.

  Further, even when stress is applied to the FPC terminal portion 43, the wiring portion 42 is hardly deformed, and stress is applied to the wiring portion 42 by concentrating the stress applied to the wiring portion 42 on the stress concentration portion 45. This can be prevented.

  As described above, according to the FPC 4 and the planar light source device 2 on which the FPC 4 is mounted, the terminal portion 43 and the terminal portion 43 even when stress such as bending force or twisting force is applied when the FPC 4 is bent. It is possible to prevent stress from being applied to the terminal portion 43 or the wiring portion 42 by concentrating the bending stiffness difference with the wiring portion 42 other than the stress concentration portion 45. By this action, it is possible to prevent the FPC 4 from being subjected to a stress such as a bending force or a twisting force, and to prevent a crack from occurring. Therefore, when the FPC terminal portion 43 is inserted into and removed from the FPC connector 6, the FPC terminal portion 43 is hardly cracked, and connection failure due to disconnection can be prevented. Since a connection failure between the connector 6 and the FPC 4 due to disconnection can be prevented, stable power can be supplied to the light source 41 mounted on the FPC 4 in the planar light source device of the present invention.

  Although the FPC used in the planar light source device has been described in the above embodiment, it can be applied to other configurations in the case of an FPC connector and FPC that are repeatedly inserted and removed, and the same effects as in the above embodiment. Play.

1 display panel, 2 planar light source device, 21 lower frame, 22 reflective sheet,
23 light guide plate, 24 optical sheet, 25 holding frame, 3 upper frame,
4 FPC, 41 light source, 42 wiring section, 421 wiring pattern,
43 terminal part, 44 reinforcing member, 45 stress concentration part (notch part),
6 connector, 61 insertion slot, 62 locking mechanism.

Claims (5)

A FPC (Flexible Printed Circuit Board) comprising a terminal portion connected to a connector and a wiring portion extending from the terminal portion and formed to supply power via the connector,
The FPC includes a connection surface of the connector and a non-connection surface arranged opposite to the connection surface, and a reinforcing member on the non-connection surface,
An FPC, wherein a stress concentration portion that changes a width of the wiring portion is formed on the wiring portion that is separated from a terminal portion of the reinforcing member by a predetermined position. The stress concentration portion is a cutout portion that continuously decreases the width of the wiring portion on which the reinforcing member is not disposed, starting from the wiring portion that is separated from the terminal portion of the reinforcing member by a predetermined position. The FPC as described. The FPC according to claim 1, wherein a plated portion that protects the wiring portion is formed on one surface of the wiring portion of the FPC, and a reinforcing member is held on a surface opposite to the plated portion. 4. The FPC according to claim 1, wherein a point light source is mounted on the wiring portion, and power is supplied from a terminal portion connected via the connector to light the point light source. 5. The FPC as described. 5. A planar light source device comprising: the FPC according to claim 4; and a frame that accommodates therein a wiring portion of the FPC and has a part of the connector that is connected to the terminal portion.

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