JP2007035481A - Plane light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plane light source device, using lamps as a light source, enabling narrower framing coping with fear that it would be difficult to achieve narrower framing by drawing around lead wires of the lamps, and unnecessarily exposing the device to the outer face of a back case might damage it by external force. <P>SOLUTION: A light guide plate 18 is housed in a back case 11, lamps 19 each with lamp holders 20, 21 at either end are arranged in opposition at a side face of the light guide plate 18, recessed parts 14 protruded outward are formed at bottom faces inside the back case 11, and lead wires 33 of the lamps 19 are housed in the recessed parts 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface light source device suitable for irradiating a transmissive liquid crystal panel such as a liquid crystal display device.

  A liquid crystal display device has low power consumption, is lightweight, suitable for thinning and downsizing, and is widely used as various monitors for personal computers, television receivers, portable terminals, navigation systems, and the like. In such a liquid crystal display device, there are a reflective liquid crystal display device and a transmissive liquid crystal display device, but a transmissive liquid crystal display device is often used in terms of brightness. In this transmissive liquid crystal display device, a surface light source device called a backlight is used, and in this surface light source device, a lamp made of a cold cathode tube and a light guide plate are used in combination.

  That is, the light guide plate and the lamp having the lamp holder are arranged such that a light guide plate is disposed in the back case, and a lamp having a lamp holder formed on the side surface of the light guide plate so as to cover both end electrode portions is opposed to the lamp. It is what.

  In this lamp holder, a lamp is inserted from one end, a lead wire is soldered and connected to the outer lead connected to the internal electrode of the lamp, and a high frequency voltage is supplied to the lamp through the lead wire. Then, the lamp is lit by AC driving.

  A reflective sheet is interposed between the light guide plate and the back case bottom plate, and an upper case is fitted and fixed to the back case.

  With this configuration, the light emitted from the lamp is introduced into the light guide plate from the side surface of the light guide plate, and part of the light is reflected by the reflection sheet, and the light emitted from the lamp is converted into the light guide plate and various kinds of light. It is used as a light source for irradiating the liquid crystal panel side using an optical sheet to display an image (see, for example, Patent Document 1).

  However, the lead wire of the lamp used in such a surface light source device is generally arranged in parallel to the lamp with respect to the back case surface. A reflector and a lead wire formed by the lamp and the reflection sheet are interposed between the inner side surfaces of the case, and it is difficult to cope with the narrow frame.

  From such a point of view, there is also a surface light source device configured to lead out the lead wire to the outside of the bottom surface of the back case and fix the lead wire by fixing means such as a groove or boss formed on the outside of the bottom surface of the back case. It is known (see, for example, Patent Document 2).

In this surface light source device, since no lead wire is interposed between the light guide plate and the inner side surface of the back case, it is considered as one means of narrowing the frame.
Japanese Patent Laying-Open No. 2005-55924 (FIG. 1) JP-A-7-225321 (FIG. 2)

  In such a surface light source device, it is difficult to deal with the narrowing of the frame, or lead wire fixing means considered to be unnecessary in the original surface light source device are only provided on the outer surface of the back case bottom plate. In addition, since the lead wire is exposed to the outside from the back case bottom plate, it may be damaged when the surface light source device is assembled or combined with the liquid crystal panel.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a surface light source device that can cope with a narrow frame while holding a lead wire in a predetermined position.

  A surface light source device according to the present invention includes a light guide plate that introduces light from a side surface and emits the introduced light in a direction of an exit surface, and a linear lamp that is disposed on a side surface of the light guide plate and has lead wires at both ends. In a surface light source device including a reflection sheet disposed on the reflection surface side of the light guide plate that reflects the light of the lamp, and a back case that accommodates the reflection sheet, the lamp, and the light guide plate, the bottom surface of the back case is outward. A protruding recess is formed, and a lead wire is accommodated in the recess.

  According to the present invention, there is provided a surface light source device in which the lead wire of the lamp can be accommodated in the back case, so that damage due to external force from the outside can be prevented and the frame can be narrowed. be able to.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a surface light source device according to the present invention will be described in detail with reference to the drawings.

  The surface light source device according to the present invention has a back case 11 as shown in FIG. As shown in FIGS. 2 and 3, the back case 11 is provided with a substantially rectangular bottom plate 12 made of a metal material such as stainless steel, and four sides of the bottom plate 12 in directions orthogonal to the bottom plate 12. It consists of a side plate 13. On the inner surface portion of the connecting portion between the bottom plate 12 and the side plate 13 of the back case 11, a concave portion 14 formed by projecting the inner surface of the bottom plate 12 in the outer direction parallel to the side plate 13 is formed in an annular shape on the inner peripheral surface. Yes. Furthermore, a notch portion 15 is formed in a substantially central portion of one side plate 13 by cutting out from the edge of the side plate 13 toward the bottom plate 12, and a plurality of flange portions 16 are formed on the side surface of each side plate 13. Yes.

  In the back case 11 configured in this manner, a white reflective sheet 17 is accommodated so as to substantially follow the inner surfaces of the bottom plate 12 and the side plate 13 while covering the recess 14. The reflection sheet 17 is formed of a synthetic resin, a reflection foil of silver, aluminum, or the like is formed on the synthetic resin by means such as sticking or vapor deposition, or is formed of aluminum foil itself. .

  On the reflection sheet 17, a light guide plate 18 formed in a substantially square shape made of a heat-resistant acrylic resin having a large number of prisms provided on one surface is disposed. Is provided with a lamp 19 composed of a cold cathode tube functioning as a linear light source. The lamp 19 includes a pair of lamp holders formed of a rubber material, an elastic synthetic resin, or the like that covers both end electrode portions of the lamp 19. 20, 21 are arranged.

  In order to arrange the lamp holders 20 and 21 at predetermined positions, locking portions 22 formed by notching the corner portions of the light guide plate 18 are provided, and the corner portions of the reflection sheet 17 are similarly provided. A locking portion 23 is formed, and the light emitting unit 24 is formed by the reflection sheet 17, the lamp 19, the light guide plate 18, and the like.

  An optical sheet 28 including a diffusion sheet 25 and a plurality of prism sheets 26 and 27 is disposed on the light guide plate 18. After the above-described various component parts including the optical sheet 28 are accommodated in the back case 11. An open case side of the back case 11 is held by a frame-like upper case 30 provided with an opening 29 in the center, and the upper case 30 and the back case 11 are provided with a through hole 31 and a flange 16 provided respectively. It is fitted and held by the engaging means.

  In addition, a wiring board 32 on which various electrical components and wiring patterns are applied is accommodated on the outer surface defined by the recesses 14 provided on the bottom plate 12 of the back case 11. The wiring board 32 is used to mount, for example, the lamp 19 or a liquid crystal panel drive circuit, and constitutes a surface light source device.

  Although not shown here, a liquid crystal panel is placed on the surface light source device, and a front case in which the liquid crystal panel is accommodated is fitted to the back case 11 or the upper case 30 and fixedly held. Thus, a liquid crystal display device including the surface light source device can be configured.

  The relationship between the components of the surface light source device configured as described above will be described in more detail.

  A lamp 19 is disposed on the side surface of the light guide plate 18 placed on the reflection sheet 17 constituting the light emitting unit 24. At this time, as shown in FIG. 4, the end of the portion of the reflection sheet 17 where the lamp 19 is disposed is folded back to the light guide plate 18 side as indicated by the arrow in the figure, and the lamp 19 is connected to the side of the light guide plate 18. By forming the reflection sheet 17 so as to be sandwiched therebetween, the reflection sheet 17 is also provided with a function as a reflector. Further, the reflection sheet 17 corresponding to the other side is also folded back to the side surface of the light guide plate 18 so that it can function as a reflector on the end surface of the light guide plate 18.

  In FIG. 4, for convenience of explanation, only the upper reflection sheet 17 in the drawing is described to be folded back, but the lower reflection sheet 17 in the drawing also has the same configuration and is illustrated. FIG. 4 shows a state in which the reflection sheet 17 is folded and a lamp (shown by a broken line in the figure) 19 is accommodated therein.

  The lamp holders 20 and 21 are fitted to both ends of the lamp 19 as described above. For this reason, the light guide plate 18 is brought into contact with one side surface of the light guide plate 18 to thereby guide the light guide plate. In order to place the lamp 19 opposite to the side surface of the lamp 18, the lamp holders 22, 21 are positioned at the corners of the light guide plate 18 so that the lamp holders 20, 21 are positioned at the corners of the light guide plate 18. Is formed.

  The locking portion 22 may be formed as necessary. If the lamp holders 20 and 21 can be directly locked to the corners of the light guide plate 18, the locking portion 22 may be omitted. Is possible.

  The lamp holders 20 and 21 are further engaged with driving voltage supply lead wires 33 and 34 electrically connected to both end electrodes of the lamp 19 and the lamp holders 20 and 21. The lead wires 33 and 34 are attracted to a lead wire support plate 35 disposed at a position corresponding to the notch 15 provided in the back case 11, and are led out from the lead wire support plate 35 to the outside. Each plug 36 is connected.

  At this time, in one lamp holder 20 separated from the lead wire support plate 35, as shown in FIG. 5, the lamp shown in FIG. 5 shows the state shown in FIG. 4 as viewed from the opposite surface side (back case side). The lead wire 33 from 19 is led out from the lamp holder 20 along the lower side of the lamp 19, and the lead wire 33 is held by the other lamp holder 21. Lead wires 33 and 34 are led out and led to a lead wire support plate 35. This configuration also adopts the same configuration on the opposite lamp 19 side.

  Accordingly, the relationship between the lamp 19, the lead wire 33 and the reflection sheet 17 is shown. As shown in FIG. 6, the reflection sheet 17 is located between the lamp 19 and the lead wire 33, and the reflection sheet 17 is folded back to reflect. The end surface portion of the reflection sheet 17 that functions as the above is positioned on the upper surface side of the lamp 19.

  That is, the lead wire 33 of the lamp 19 is in a two-stage configuration with a predetermined distance from the lamp 19 so that the lead wire 33 is substantially parallel to the lamp 19 from one lamp holder 20 to the other lamp holder 21 side. Thus, the wiring is routed around the outside of the reflection sheet 17.

  In other words, the lamp 19 and the lead wire 33 are arranged at predetermined intervals in the upper and lower stages with respect to the thickness direction of the light guide plate 18 so that the lamp 19 and the lead wire 33 are separated in this gap portion. In this configuration, the reflective sheet 17 is interposed between the two.

  The lamp holders 20 and 21 for adopting such a configuration will be described in more detail with reference to FIGS.

  FIG. 7 shows one lamp holder 20 for turning back the lead wire 33 from the lamp 19 so as to be substantially parallel to the lamp 19. FIG. 7 (a) is a perspective view, and FIG. ) Shows a front view.

  The lamp holder 20 covers the electrode portion of the lamp 19 and holds the lead wire 33 connected to the electrode. The lamp holder 20 is made of a rubber material, elastic synthetic resin, etc. A main body 37 is formed in a column shape. A lamp fitting hole 38 having a bottomed cylindrical shape for fitting one end portion of the lamp 19, that is, an electrode portion, is formed in the main body 37 portion of the lamp holder 20. A lead wire holding hole 39 is formed below the lamp fitting hole 38 in communication therewith.

  Further, the upper surface of the main body 37 is formed in three steps, and the upper flat portion 40 at the lowest step is used as a surface on which the folded portion of the reflection sheet 17 is placed, and the intermediate flat portion 41 is an optical plate. Although used as a placement surface for the sheet 28 or the like, the uppermost flat portion 42 can also be used as a placement surface for the optical sheet 28. It is also possible to omit the intermediate plane portion 41 to have a two-stage configuration, and use the uppermost plane portion 42 as a mounting surface of the optical sheet 28. Is possible.

  A locking piece 43 that extends integrally in a direction orthogonal to the main body 37 is formed from the end face on the opposite side to the end face provided with the lamp fitting hole 38 of the main body 37. The locking piece 43 is used to lock the corner portion of the light guide plate 18 between the locking piece 43 and the main body 37, and is used for restricting the position of the lamp holder 20.

  In FIG. 7, only one lamp holder 20 of the pair of lamps 19 is illustrated, but the lamp holder 20 of the lamp 19 on the other side uses the lamp holder 20 in a horizontally reversed state. The basic configuration is the same.

  On the other hand, the other-side lamp holder 21 mounted on the other-side end portion of the lamp 19 is configured as shown in FIG.

  8A is a perspective view of the lamp holder 21, and FIG. 8B is a front view.

  Similarly to the lamp holder 20 on the one side, the lamp holder 21 covers the electrode portion of the lamp 19, and the lead wire 34 connected to the electrode and the lead wire 33 from the lamp holder 20 on the one side. The main body 44 is formed in an L-shaped column shape in a plan view from a rubber material, an elastic synthetic resin, or the like. A lamp fitting hole 45 having a bottomed cylindrical shape for fitting one end portion of the lamp 19, that is, an electrode portion, is formed in the main body 44 portion of the lamp holder 21.

  Since the lead wire 34 connected to the electrode of the lamp 19 fitted in the lamp fitting hole 45 does not need to be folded back along the lamp 19, the lead wire 34 protrudes in an L-shape from the main body 44 in a substantially right angle direction. The configuration is such that the lead-out hole 47 provided in the stop 46 leads to the outside, and the configuration is different from that of the one lamp holder 20 described in FIG.

  Further, the lower portion of the main body 44 and the locking portion 46, that is, the bottom surface portion parallel to the lamp 19 and the bottom surface portion parallel to the lead wire 34 are parallel to the main body 44 and the locking portion 46, respectively. Thus, a lead wire holding portion 49 formed of tongue pieces 48 facing each other is formed. A concave groove 50 for guiding the lead wire 33 is formed inside the tongue pieces 48 facing each other. The lead wire 33 led out from one lamp holder 20 and led out along the lamp 19 by the lead wire holding portion 49 is formed on the lower surface of the other lamp holder 21 as shown in FIG. It is engaged with the lead wire holding portion 49, bent into an L shape along the shape of the lamp holder 21, and guided to the lead wire support plate 35.

  Note that the upper surface of the main body 44 is formed in three steps, and these three-step flat portions have the same functions as those of the one lamp holder 20 described in FIG. A detailed description thereof will be omitted.

  In FIG. 8, only one lamp holder 21 of the pair of lamps 19 is shown, but the lamp holder 21 of the lamp 19 on the other side uses the lamp holder 21 in a horizontally reversed state. The basic configuration is the same.

  In this way, the lead wire 33 led out from one lamp holder 20 by the pair of lamp holders 20 and 21 fitted to both ends of the lamp 19 allows the other lamp holder to keep the predetermined distance from the lamp 19. 21, the two lead wires 33 and 34 connected to the electrode portions at both ends of the lamp 19 are led out from the other lamp holder 21 together. 34 is led out from the notch 15 of the back case 11 through the lead wire support plate 35.

  As described above, since the lead wire 33 is routed substantially parallel to the lamp 19, the lead 19 is positioned on the substantial lead wire 33. Therefore, only the lead wire 33 portion is taken. Can be introduced into the recess 14 of the back case 11 and drawn around, so that the frame can be made narrower.

  In addition, since the lead wire 33 is wired so as to pass through the recess 14 of the back case 11, no special member such as a fixed boss is used, so that the lead wire 33 may be caught carelessly during work. It is possible to prevent damage due to external force.

  In addition, if the reflection sheet 17 is interposed in the gap portion between the lamp 19 and the lead wire 33, the lead wire 33 is completely separated and cut off from the light emitting portion. Even if there is, there is no adverse effect on the function as a light source.

  Furthermore, if the wiring board 32 is arranged on the back surface of the bottom plate 12 of the back case 11, the partition portion formed by the recess 14 can be used effectively, and the wiring board 32 can be accommodated in the bottom plate 12 portion. Thus, the wiring board 32 and the back case 11 can be integrated.

  In addition, in the said embodiment, although the structure which has arrange | positioned the straight tubular lamp | ramp 19 in the one side surface which the light-guide plate 18 opposes, a pair of lamp | ramp 19 is each arrange | positioned on the both side surfaces which the light-guide plate 18 oppose. The present invention can also be applied to the configuration and the case where a single lamp 19 is disposed only on one side surface, and can also be applied to the case where an L-shaped lamp 19 is employed. It goes without saying that various applications and modifications can be made to the components.

The disassembled perspective view which shows the surface light source device which concerns on this invention. The front view which similarly shows the back case which comprises a surface light source device. The rear view which similarly shows a back case. The front view which shows the light emission unit which comprises a surface light source device similarly. The rear view which similarly shows a light emission unit. The partially excerpt side view which similarly shows the light emission unit. It is a figure which shows the lamp holder of the one side which comprises a surface light source device similarly, (a) is a perspective view, (b) is a front view. It is a figure which shows the lamp holder of the other side which comprises a surface light source device similarly, (a) is a perspective view, (b) is a front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Back case 14 ... Recessed part 17 ... Reflective sheet 18 ... Light guide plate 19 ... Lamp 20, 21 ... Lamp holder 32 ... Wiring board 33 ... Lead wire

Claims (5)

A light guide plate that introduces light from the side surface and emits the introduced light in the direction of the emission surface, a linear lamp that is disposed on the side surface of the light guide plate and has lead wires at both ends, and the light that reflects the light of the lamp In a surface light source device including a reflection sheet disposed on a reflection surface side of a light guide plate, the reflection sheet, the lamp, and a back case that houses the light guide plate,
A surface light source device, wherein a concave portion protruding outward is formed on the bottom surface of the back case, and the lead wire is accommodated in the concave portion. The surface light source device according to claim 1, wherein the lamp is installed on an upper side of a lead wire accommodated in the recess. The surface light source device according to claim 2, wherein the reflection sheet is interposed between the lamp and the lead wire. 4. The surface light source device according to claim 2, wherein the lamp and the lead wire are held by the same lamp holder. The surface light source device according to claim 1, wherein a wiring board is disposed outside the bottom surface of the back case defined by the recess.

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