JP2013045512A - Planar light source device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring protection means of a flat cable in a planar light source device and a display device, which prevents the flat cable from being damaged by contact with other members such as a case, while preventing foreign matter from entering the case and also preventing light from leaking to the outside of the case.SOLUTION: The planar light source device and the display device include a slit 51 to insert a power supply unit 22 of the flat cable 2 into in a reflection sheet 5 arranged at a position corresponding to a lead-out part 71 of an under case 7. The slit 51 is formed with a predetermined distance from an edge 72 to make the lead-out part 71.

Description

  The present invention relates to a planar light source device and a display device that displays an image by arranging a display element on an emission surface of the planar light source device.

  As shown in Patent Document 1, the conventional planar light source device includes a light guide plate, a light source, an optical sheet, an electric circuit connected to the light source, and a case for housing them, and the case from the case via the wiring lead-out portion. A flat cable (flexible printed circuit board) led out to the outside and an optical sheet are provided, and a wiring protection part interposed between the wiring lead-out part and the flat cable is provided.

JP 2009-163952 A

  However, the backlight unit and the display device disclosed in Patent Document 1 have a problem that the flat cable is not sufficiently protected because the flat cable touches the edge of the case. In addition, since the wiring lead-out portion has a large opening, there is a problem that foreign matter enters the case and light from the light source leaks to the outside.

  The planar light source device and the display device of the present invention solve the above problems and provide a means for protecting the flat cable wiring that prevents the flat cable from being damaged. The purpose of the flat cable wiring protection means is to prevent foreign matters from entering the case and prevent light from leaking outside the case.

  A planar light source device and a display device according to the present invention include a light source, a flat cable including a light source mounting unit for mounting the light source, and a power supply unit for supplying power to the light source, and a reflection sheet for reflecting light from the light source. A light source, a light source mounting portion of the flat cable, a case having a reflection sheet stored therein, and a lead-out portion that leads out the power supply portion of the flat cable to the outside, and the reflection sheet disposed in the lead-out portion Is characterized in that a slit is formed at a position having a predetermined interval with respect to the edge constituting the lead-out part, and a power supply part of a flat cable is inserted into the slit.

  According to the present invention, it is possible to prevent the flat cable from being damaged, to prevent foreign matter entering the planar light source device from the lead-out portion of the case, and light from the planar light source device leaks from the lead-out portion. Can be suppressed.

It is a disassembled perspective view of the display apparatus which concerns on this invention. It is a top view of the planar light source device according to the present invention. It is sectional drawing of the planar light source device which concerns on this invention. It is a principal part enlarged view of the planar light source device which concerns on this invention. It is a principal part enlarged view of the planar light source device which concerns on this invention. It is a principal part enlarged view of the reflective sheet which concerns on this invention. It is sectional drawing of the planar light source device which concerns on this invention. It is a principal part enlarged view of the reflective sheet which concerns on this invention. It is sectional drawing of the planar light source device which concerns on this invention. It is a principal part enlarged view of the planar light source device which concerns on this invention. It is sectional drawing of the planar light source device which concerns on this invention. It is sectional drawing of the planar light source device which concerns on this invention. It is a principal part enlarged view of the reflective sheet which concerns on this invention. It is a top view of the reflective sheet which concerns on this invention.

(Embodiment 1)
A configuration of a display device according to the present invention will be described with reference to the drawings. In addition, what uses the same code | symbol in each figure shows the substantially same structure. 1 is an exploded perspective view of a display device according to the present invention, FIG. 2 is a plan view of the planar light source device shown in FIG. 1, and FIG. 3 is a view from the II direction with the planar light source device of FIG. Sectional drawing, FIG. 4, FIG. 5 is the principal part enlarged view of a planar light source device.

<Overall configuration>
As shown in FIG. 1, a planar light source device 10 according to the present invention includes a plurality of point light sources 1 such as LEDs arranged in a line and mounted on a flat cable 2. The point light source 1 is disposed in the vicinity of the incident surface 3a of the light guide plate 3 that propagates light (the side surface on which light is incident from the light source is referred to as the incident surface 3a), and the light of the point light source 1 incident from the incident surface 3a. Propagates through the light guide plate 3 and is emitted from the exit surface 3b of the light guide plate 3 (the surface above the paper surface of the light guide plate 3 in FIG. 1). The optical sheet 4 is provided on the light exit surface 3b side of the light guide plate 3, and the reflection sheet 5 is disposed on the side opposite to the light exit surface 3c of the light guide plate 3 (the surface below the light guide plate 3 in FIG. 1). Yes. In the planar light source device 10 shown in FIG. 1, the point light source 1, the flat cable 2, the light guide plate 3, the optical sheets 4, and the reflection sheet 5 are accommodated in the lower case 7 and sandwiched between the upper case 6. Yes. The upper case 6 is provided with an opening 6 a, and the opening 6 a corresponds to the emission surface 3 b of the light guide plate 3. Therefore, the planar light source device 10 emits planar light from the opening 6a. Further, the size of the opening 6 a is designed to be inside the outer periphery of the light guide plate 3.

<Point light source>
As a light source used in the present embodiment, there are a point light source such as a laser diode (Laser Diode) and a linear light source such as a cold cathode fluorescent lamp in addition to the LED. In particular, the LED may be a semiconductor light emitting element that emits a single color such as blue, or a pseudo white LED made of a phosphor that absorbs a part of blue light emitted from the semiconductor light emitting element and emits yellow light. . In some cases, the LED includes an element of RED (red), GREEN (green), and BLUE (blue) and emits white light by combining light into three monochromatic lights. In the present embodiment, a pseudo white LED is used as the point light source 1.

<Flat cable>
The flat cable 2 (FFC: Flexible Flat Cable) which is a light source substrate includes a flexible printed circuit (FPC). In general, the flat cable 2 has a structure in which an adhesive layer is formed on a film-like insulator (base film) having a thickness of 12 μm to 50 μm, and a conductive foil having a thickness of about 12 μm to 50 μm is formed thereon. For this reason, the flat cable 2 can be made thin. In addition, it can be repeatedly deformed with a small force, and electrical characteristics can be maintained even when deformed.

  As shown in FIG. 1, the point light source 1 is mounted on a light source mounting portion 21 of a flat cable 2 which is a light source substrate at a predetermined interval. In addition, a power supply unit 22 extending from the light source mounting unit 21 is provided to supply power to the point light source 1. The light source mounting portion 21 of the flat cable 2 is disposed so as to face the incident surface 3 a of the light guide plate 3, and is fixed to the inner surface of the lower case 7 with double-sided tape or an adhesive. In FIG. 1, the point light source 1 and the flat cable 2 are provided only on one side surface (incident surface 3 a) of the light guide plate 3, but the present invention is not limited to this and is provided on two or more side surfaces of the light guide plate 3. A point light source 1 and a flat cable 2 may be disposed. The flat cable 2 holds the point light source 1 and is formed with a circuit pattern for supplying power to the point light source 1. Further, by using the flat cable 2 having a thin substrate thickness as the light source substrate, the heat from the mounted point light source 1 can be more efficiently transmitted to the surroundings. Moreover, the external size of the planar light source device can be reduced. In addition, the cable line etc. which supply electricity to a light source instead of the flat cable 2 can also be used.

<Light guide plate>
The light guide plate 3 is made of a material such as transparent acrylic resin, polycarbonate resin, or glass. A light scattering portion (not shown) for guiding the light to the emission surface 3b by disturbing the propagation direction of the light is formed on the counter-exit surface 3c of the light guide plate 3. This light scattering portion functions as a means for reflecting light toward the inside of the light guide plate 3. Specifically, a method of printing a dot pattern on the anti-emission surface 3c, a method of making the anti-emission surface 3c rough, and irregularities that change the propagation direction of light, such as minute spherical surfaces and prisms, are formed on the anti-emission surface 3c. There is a method of forming.

<Reflection sheet>
The reflection sheet 5 is formed using a material obtained by mixing barium sulfate or titanium oxide with PP (polypropylene) or PET (polyethylene terephthalate). Further, the reflective sheet 5 may be made of a material in which fine bubbles are formed in a resin, a material in which silver is vapor-deposited on a metal plate, a material in which a paint containing titanium oxide or the like is applied to the metal plate, or the like. Note that the reflection sheet 5 desirably has a reflectance of 90% or more. Therefore, the reflectance may be increased by stacking a plurality of reflection sheets 5. By increasing the reflectance of the reflection sheet 5, the luminance of the planar light source device 10 increases. Further, by applying dot pattern printing to the light guide plate 3 side surface or the anti-light guide plate 3 side surface of the reflection sheet 5, it is possible to improve luminance uniformity on the light exit surface 3 b of the light guide plate 3. Further, by performing colored printing on the reflection sheet 5, it is possible to cancel the color change at the emission surface 3 b caused by the light absorption of the light guide plate 3 or the light absorption of the reflection sheet 5. When printing on the surface of the reflection sheet 5 on the side opposite to the light guide plate 3, it is possible to finely adjust the influence on the emission surface 3 b, and to further control and suppress luminance unevenness and color unevenness between the point light sources 1. There is a merit that it becomes easy. As shown in FIG. 1, the reflection sheet 5 is disposed on the side opposite to the light emitting surface 3 c of the light guide plate 3, but is also emitted from the side surface of the light guide plate 3 by disposing the reflection sheet 5 on the side surface other than the incident surface 3 a. Can be returned to the light guide plate 3 again, and the luminance at the exit surface 3b can be improved.

<Optical sheet>
On the light guide plate 3, optical sheets 4 composed of a plurality of optical sheets are arranged. Specifically, the optical sheets 4 have a configuration in which a lens sheet is sandwiched between diffusion sheets. Moreover, when improving the brightness | luminance of a planar light source device, you may combine several lens sheets in consideration of the prism direction formed in the surface of a lens sheet. In addition, two or more diffusion sheets can be used in combination in order to improve the diffusibility. Depending on the light distribution characteristics of the lens sheet, the optical sheet 4 may have a single lens sheet or may not be used. Further, the optical sheets 4 may be combined with a protective sheet, a lens sheet, or a polarizing reflection sheet 5. The use of the optical sheets 4 is preferably optimized in view of the required luminance, light distribution characteristics, and the like.

<Upper case>
The upper case 6 has an opening 6a through which light from the light exit surface 3b of the light guide plate 3 is transmitted, and is configured so that light does not leak outside as much as possible from other parts. The upper case 6 can be made of a metal material such as aluminum, stainless steel, or iron, or a resin material such as PC (polycarbonate) or ABS (acrylonitrile butadiene styrene).

<Lower case>
The lower case 7 has a function of conducting heat emitted from the point light source 1 and releasing it to the surroundings. Further, the lower case 7 is required to store each member and to be positioned at a predetermined position, so that high strength is required. For this reason, the lower case 7 is preferably a metal having high strength and high thermal conductivity. In particular, by using an aluminum or aluminum alloy case having high thermal conductivity for the lower case 7, heat from the point light source 1 can be efficiently diffused, and the temperature of the point light source 1 can be lowered. In order to efficiently release the heat spread to the lower case 7 to the atmosphere, the lower case 7 is particularly preferably disposed on the outermost periphery of the planar light source device.

<Display device>
In the planar light source device 10, the display element 9 is disposed on the opening 6 a of the upper case 6 to configure the display device 100. The display element 9 is disposed on the emission surface 3 b of the light guide plate 3 via the optical sheet 4. When the display element 9 using the birefringence of liquid crystal is used, the display element 9 includes an opposing substrate in which a colored layer, a light shielding layer, a counter electrode, and the like are formed on an insulating substrate such as glass, and an insulating property such as glass. A thin film transistor (TFT) serving as a switching element and a TFT array substrate on which pixel electrodes and the like are formed are provided on a substrate (not shown). Then, a spacer for maintaining the distance between the counter substrate and the TFT array substrate, a sealing material for bonding the counter substrate and the TFT array substrate, a liquid crystal sandwiched between the counter substrate and the TFT array substrate, and a liquid crystal It is comprised by the sealing material of the injection port to inject | pour, the alignment film which distributes light of a liquid crystal, a polarizing plate, etc. (not shown).

  The display device 100 includes a circuit board (not shown) for driving the display element 9. On the circuit board, a copper pattern is formed on glass epoxy or the like, and a plurality of electronic components are mounted by soldering. The circuit board is mainly disposed on the back surface side (the side where light is not emitted) of the planar light source device 10 and is mechanically connected to the planar light source device by fixing screws, caulking, hooking claws, and the like. A protective cover (not shown) is attached to protect the circuit board from external pressure and static electricity. As a material for the protective cover, aluminum, stainless steel, galvanized steel sheet, or the like is used. Further, a resin sheet (not shown) such as PET is attached to the circuit board side of the protective cover in order to avoid electrical contact with the circuit board and electronic components on the circuit board. The protective cover is mechanically connected to the back surface of the planar light source device by screws, caulking or the like. Further, the protective cover has a hole (through hole) in the vicinity of the variable resistor so that the variable resistor on the circuit board can be controlled after being attached. The protective cover can be replaced with a PET sheet when the external pressure or the like is not large. In this case, since there is no need to attach an insulating sheet between the circuit boards, the number of parts can be reduced and the cost can be reduced.

<Derived part>
The lower case 7 is formed with a lead-out portion 71 for leading the flat cable 2 out of the lower case 7. As shown in FIG. 1, as an example, the lead-out portion 71 is formed by a rectangular hole having an edge 72. As shown in FIG. 3, the power supply unit 22 extending from the light source mounting unit 21 is led out of the lower case 7 through the lead-out unit 71 of the lower case 7. In addition, the power supply part 22 derived | led-out from the derivation | leading-out part 71 connects with the other member arrange | positioned outside the lower case, and supplies electric power to the flat cable 2 (not shown).

  As shown in FIG. 1 or FIG. 4, the reflective sheet 5 arranged in the lead-out portion 71 of the lower case 7 is provided with a slit 51 at a position corresponding to the lead-out portion 71. The slit 51 is formed at a position away from the edge 72 constituting the lead-out portion 71 with a predetermined interval. Then, as shown in FIG. 5, the flat cable 2 is disposed so as to face the incident surface 3 a of the light guide plate of the lower case 7, and the power supply unit 22 of the flat cable 2 is inserted into the slit 51 of the reflection sheet 5, Derived from the deriving unit 71 to the outside of the lower case 7. As described above, when the power supply unit 22 of the flat cable 2 is led out of the lower case 7 from the lead-out part 71, the flat cable is inserted into the slit 51 of the reflection sheet 5 formed at a position away from the edge 72 of the lead-out part 71. 2 is inserted. For this reason, it can prevent that the flat cable 2 contacts the edge 72 of the derivation | leading-out part 71, the flat cable 2 is disconnected, and the point light source 1 does not light. The slit 51 is provided at a substantially middle position between the edges 72 of the lead-out portions 71 facing each other, so that the flat cable 2 comes into contact with the edge 72 of the lower case 7 even if the reflective sheet 5 is slightly displaced. Can be prevented.

  Further, as shown in FIG. 4, the length H of the slit 51 is formed larger than the width of the power supply unit 22 of the flat cable 2. Specifically, by making the width of the power supply part 22 of the flat cable 2 about 0.5 mm to 1 mm larger, a margin for inserting the flat cable 2 is left, and foreign matter insertion and light leakage are prevented. Can do. The width of the slit 51 is preferably equal to or less than the thickness of the power supply unit 22 of the flat cable 2 inserted into the slit 51. By forming it with a thickness equal to or less than that, insertion of foreign matter and light leakage can be prevented. Further, round holes are formed at both ends of the slit 51. The round hole can alleviate stress concentration at the end of the slit 51 when the power supply unit 22 of the flat cable 2 is inserted into the slit 51, and can prevent the slit 51 from being cut. The slit 51 of the reflection sheet 5 is formed by using Thomson mold processing or the like.

  Next, a method for assembling the planar light source device 10 according to the first embodiment will be described with reference to FIGS. First, the light source mounting portion 21 of the flat cable 2 on which the point light source 1 is mounted is fixed to the inner surface of the lower case 7 with a double-sided tape, an adhesive, or the like. Next, the reflection sheet 5 is installed on the inner surface of the lower case 7. Next, the power supply part 22 of the flat cable 2 is inserted into the slit 51 of the reflection sheet 5 and pulled out from the lead-out part 71 of the lower case 7. Thereafter, the light guide plate 3 and the optical sheets 4 are installed, and the upper case 6 is engaged with the lower case 7.

  As described above, the planar light source device according to the first embodiment has the slit 51 for inserting the power supply unit 22 of the flat cable 2 into the reflection sheet 5 disposed at a position corresponding to the lead-out unit 71 of the lower case 7. I have. Since the slit 51 is formed with a predetermined distance from the edge 72 that forms the lead-out portion 71, the power supply portion 22 of the flat cable 2 can be arranged at a position away from the edge 72, and thus the edge 72 of the lead-out portion 71. It is possible to prevent the point light source 1 from being unlit due to the power supply unit 22 of the flat cable 2 being disconnected in contact with.

  6 and 7 show modifications of the reflection sheet 5 used in the first embodiment. FIG. 6 is an enlarged view of a main part of the reflection sheet 5 used in the first embodiment, and FIG. 7 is a cross-sectional view when the reflection sheet 5 shown in FIG. 6 is arranged in a planar light source device. As shown in FIG. 6A, the reflection sheet 5 includes an extension portion 52 that protrudes from one side portion 50 disposed on the incident surface 3 a side of the light guide plate 3 and extends in accordance with the shape of the lead-out portion 71. Yes. The reflection sheet 5 can further prevent foreign matter insertion and light leakage by arranging the lead-out portion 71 so as to cover the lead-out portion 71 from the inner surface side of the lower case 7. Accordingly, it is possible to prevent a foreign matter from entering the display surface of the display element and causing a display defect of the display device, and to prevent light leakage from the derivation unit 71.

  In addition, the extension part 52 is good also as a structure (not shown) bent so that the inner side part of the lower case 7 may be followed. Thereby, the insertion of foreign matter from the outside can be prevented, and the brightness can be further prevented from being lowered by the light leaking from the light guide plate 3.

  Further, as shown in FIG. 6B, a slit 51 may be formed in the extension portion 52. In this case, the slit 51 formed in the extension 52 extends to one end 521 of the extension 52. With this configuration, workability can be improved when the power supply unit 22 of the flat cable 2 is inserted into the reflection sheet 5.

(Embodiment 2)
8 is an enlarged view of a main part of the reflection sheet 5 disposed in the planar light source device according to the present embodiment, FIG. 9 is a cross-sectional view of the planar light source device in which the reflection sheet 5 of FIG. 8 is disposed, and FIG. The front view of the planar light source device when the reflective sheet 5 is arranged is shown. In the planar light source device in the first embodiment, the reflection sheet 5 has an example in which there is one slit 51 provided corresponding to the lead-out portion 71 of the lower case 7, but the surface according to the second embodiment. In the light source device, as shown in FIGS. 8 to 10, the reflective sheet 5 is provided with a plurality of slits 511 and 512, and the reflective sheet 5 arranged corresponding to the lead-out portion 71 has a double structure. The configuration other than the configuration described in the second embodiment is the same as the first embodiment. In addition, the same operational effects as the display device according to the first embodiment are obtained except for the specific operational effects of the display device according to the second embodiment described below.

  As shown in FIGS. 8 to 10, the reflection sheet 5 used in the second embodiment is provided with an extension 52 that protrudes from one end 50 of the reflection sheet 5, and at least one perforation 53 provided in the extension 52. Along the outer side of the lower case 7 is bent 180 degrees to form a double structure. In the double structure portion of the reflection sheet 5, the light guide plate 3 side is the A portion, the lower case 7 side is the B portion, and slits 511 and 512 are formed in the A portion and the B portion, respectively. The extension portion 52 is formed so that the perforation 53 is bent symmetrically, and the slits 511 and 512 overlap each other at the same position in plan view. Further, as shown in FIG. 6, round holes are formed at the ends of the slits 511 and 512.

<Assembly method>
Next, a method for assembling the planar light source device of the second embodiment will be described. First, the light source mounting portion 21 of the flat cable 2 on which the point light source 1 is mounted is fixed to the inner surface of the lower case 7 with a double-sided tape, an adhesive, or the like. Next, the reflection sheet 5 is installed on the inner surface of the lower case 7. At that time, the extension part 52 of the reflection sheet 5 is pulled out of the lower case 7 from the lead-out part 71. The perforation 53 of the extended portion 52 that is pulled out is bent approximately 180 degrees outward. Next, the power supply part 22 of the flat cable 2 is pulled out to the outside of the lower case 7 from the lead-out part 71 through the slits 511 and 512 formed in the extension part 51. Thereafter, the light guide plate 3 and the optical sheets 4 are installed, and the upper case 6 is put on the lower case 7.

  According to the configuration of the second embodiment, the flat cable power supply unit 22 directly contacts the edge 72 of the lead-out unit 71 by the slit 511 formed in the part A, and the wiring of the power supply unit 22 of the flat cable 2 is performed. Can be prevented, and the point light source 1 can be prevented from becoming unlit, and the slit 512 formed in the portion B can prevent the movement of the power supply portion 22 of the flat cable in the vicinity of the lead-out portion 71. . Thereby, it can prevent more reliably that the power supply part 22 of the flat cable 2 contacts the edge 72.

  Further, as shown in FIGS. 9 and 10, the double folding position (perforated slit 53) of the reflection sheet 5 may be extended to a position covering the lead-out portion 71 formed in the lower case 7. It may protrude from the case 7. Thereby, the light emitted from the point light source 1 or the light guide plate 3 can be prevented from leaking from the lead-out portion 71 of the lower case 7. In addition, it is possible to prevent foreign matter from entering the surface light source device and causing display defects.

  It is desirable that the lengths of the slits 511 and 512 be appropriately larger than the width of the power supply unit 22 of the flat cable 2 to be inserted. In addition, the width of the slits 511 and 512 is desirably equal to or less than the thickness of the power supply unit 22 of the flat cable 2. Moreover, the both ends of the slits 511 and 512 can be rounded to prevent the slits 511 and 512 from being cut when the flat cable 2 is inserted.

  In the extension part 52 of the reflection sheet 5, it is possible to change the length (H) of the slit 511 formed in the A part and the slit 512 formed in the B part. By changing the lengths of the slit 511 and the slit 512, the light leaking from the round holes at both ends of the slits 511 and 512 and the foreign material entrance path are formed so as not to be a straight line. Can be difficult.

  A modification of the second embodiment is shown in FIG. FIG. 11 is a cross-sectional view of a planar light source device according to this modification. As shown in FIG. 11, in the extension portion 52 of the reflection sheet 5, the bent end portion of B is inserted between the lower case 7 and the light guide plate 3. Thereby, the reflection sheet 5 can be fixed, the reflection sheet 5 can be prevented from jumping out, and the reflection sheet 5 can be prevented from being displaced or moved. As described above, since the displacement of the reflection sheet 5 and the movement of the reflection sheet 5 can be prevented, it is possible to more reliably prevent the power supply unit 22 of the flat cable 2 from coming into contact with the edge 72 of the lead-out unit 71. Can do.

  In the second embodiment, the slits 511 and 512 of the reflection sheet 5 are formed so that the slits 511 and 512 overlap at the same position in plan view when bent by the perforation 53 by approximately 180 degrees. By forming them at different positions, it is possible to further prevent light from the point light source 1 and the light guide plate 3 from leaking, and to prevent foreign matter from entering from the outside.

(Embodiment 3)
FIG. 12 is a cross-sectional view of the planar light source device according to the third embodiment, and FIG. 13 is an enlarged view of a main part of the reflection sheet 5. Except for the configuration according to the third embodiment shown in FIGS. 12 and 13, the configuration is the same as the first and second embodiments. In addition, since the operational effects similar to those of the display device according to the first and second embodiments are obtained except for the specific operational effects of the display device according to the third embodiment described below, the description thereof is omitted.

  The extension part 54 formed in the reflective sheet 5 will be described with reference to FIGS. The extension part 54 protrudes from the one end part 50 of the reflection sheet 5 and is bent by a plurality of bending parts provided in the extension part 54 to form a double structure. Further, the extension portion 54 is disposed between the portions where the light source is not disposed, that is, between the point light sources 1, and the portion facing the incident surface 3 a of the light guide plate 3 is the X portion, and the light source mounting portion of the X portion and the flat cable 2. A portion disposed between the lower case 7 and the Y portion extends from the Y portion, and a portion derived from the lead-out portion 71 of the lower case 7 is defined as a Z portion.

  The X portion is bent 90 degrees in the cross-sectional view direction by a slit or perforation 541 provided between the extension portion 54 and the one end portion 50, and enters the light incident surface 3 a of the light guide plate 3 and the light source mounting portion 21 of the flat cable 2. It intervenes between. Next, the Y portion is connected to one side of the X portion, and is bent approximately 180 degrees toward the light source mounting portion 21 side of the flat cable 2 by a slit or perforation 542 provided in the connecting portion of both. A slit 513 is provided in the Y portion. Further, the Z portion is connected to the Y portion on one side, and is formed by being bent about 90 degrees by a slit 543 provided in the connecting portion. Further, a slit 514 is provided in the Z portion.

  The power supply part 22 of the flat cable 2 is first inserted into a slit 513 provided in the Y part of the reflection sheet 5 and led out from the light source mounting part 21 side to the light guide plate 3 side. Next, it is inserted into a slit 514 provided in the Z portion and led out to the outside of the planar light source device 10. The Z portion slit 514 is formed at a distance from the edge 72 of the lead-out portion 71 of the lower case 7 to prevent the flat cable 2 from coming into contact with the edge 72 of the lead-out portion 71 and damaging the flat cable 2. Can do. Moreover, since the power supply part 22 of the flat cable 2 is disposed between the Y part and the X part by the slit 513 provided in the Y part, it can be prevented from directly facing the incident surface 3 a of the light guide plate 3. By efficiently reflecting the light leaking from the light guide plate 3 by the reflection sheet 5 and returning it to the light guide plate 3, the light use efficiency can be improved and the luminance of the planar light source device 10 can be increased.

  Further, as shown in the cross-sectional view of FIG. 12, in the lead-out portion 71 of the lower case 7, the light from the point light source 1 can be leaked to the outside because it is covered by the extended portion 54 of the reflection sheet 5. In addition, it is possible to prevent foreign matter from entering from the outside via the lead-out portion 71.

  In this embodiment, one slit is provided in each of the Y part and the Z part, but it is also possible to provide two slits in the Y part or two slits in the Z part.

  As in the first embodiment, the slits 513 and 514 are formed by extending the slit to the end portion of the extension portion, thereby facilitating the insertion of the power supply portion 22 of the flat cable 2 and improving the assemblability.

  FIG. 14 shows a modification of the third embodiment. FIG. 14 is a plan view of the reflection sheet. As shown in FIG. 14, the reflection sheet 5 according to the third embodiment protrudes from the one end portion 50 between the point light sources 1 of the light source mounting portion 21 of the flat cable 2 in addition to the extension portion 54, and the incident surface of the light guide plate 3. The extension part 55 extended to the surface which opposes 3a was formed. Accordingly, the light from the point light source 1 and a part of the light emitted from the incident surface 3a of the light guide plate 3 are reflected by the surface of the reflection sheet 5 and enter the light guide plate 3 again. The light utilization efficiency of 10 can be improved and the luminance can be increased. Since the reflection sheet 5 does not extend around the point light source 1 mounting portion, it has a comb shape as shown in FIG.

  In addition, about the structure demonstrated in said each embodiment, it can apply variously in the range which does not deviate from the effect of this invention.

1 point light source, 2 flat cable, 21 light source mounting part, 22 power supply part,
3 light guide plate, 3a entrance surface, 3b exit surface, 4 optical sheets, 5 reflection sheet,
51, 511, 512 slit, 52, 54 extension, 53 perforation,
6 Upper case, 7 Lower case, 71 Deriving part, 72 Edge of deriving part,
9 display element, 10 planar light source device, 100 display device.

Claims (10)

A light source;
A flat cable provided with a light source mounting part for mounting the light source and a power supply part for supplying power to the light source;
A reflective sheet that reflects light from the light source;
The light source, the light source mounting part of the flat cable, the case having a lead-out part that houses the reflection sheet inside and leads out the power supply part of the flat cable to the outside, and is disposed in the lead-out part The reflective sheet is formed with a slit at a position having a predetermined interval with respect to the edge constituting the lead-out part,
A planar light source device, wherein a power supply part of the flat cable is inserted into the slit. The reflection sheet disposed in the lead-out portion protrudes from one end portion of the reflection sheet, forms an extension corresponding to the lead-out portion, and covers the lead-out portion from the inner surface side of the case by the extension. The planar light source device according to claim 1, wherein: The planar light source device according to claim 2, wherein the slit is formed in the extension portion. The extension portion is a double structure bent along a bent portion formed in the extension portion, and a plurality of the slits are formed at positions overlapping or different from each other at the same position in plan view. The planar light source device according to claim 2 or 3. 5. The slit formed in the reflection sheet is provided in the extension portion, and one end portion of the slit extends to one end portion of the extension portion. The planar light source device according to any one of the above. The planar light source device according to claim 2, wherein the reflection sheet has a round hole formed at an end portion of at least one slit portion. The planar light source device according to claim 4, wherein the bent portion of the reflection sheet is a perforated slit. In the light source mounting portion, a plurality of point light sources are arranged,
The extension portion is disposed between the point light sources, is disposed at a position facing the light source mounting portion and the lead-out portion, and includes a double structure bent by a bending portion,
The planar light source device according to claim 3, further comprising a slit into which the power supply unit is inserted at a position facing the light source mounting unit and a position facing the lead-out unit. The planar light source device according to claim 1, wherein the light source is a light emitting diode. A display device comprising a display element that is disposed to face the planar light source device according to claim 1 and that displays an image by light emitted from the planar light source device.

Images