JP3850173B2 - Sidelight type surface light source device and liquid crystal display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sidelight type surface light source device and a liquid crystal display device. By forming an inclined surface that is farther from the exit surface of the light plate and pressing the incident surface side edge of the light guide plate against this inclined surface, light leakage and abnormal light emission in the vicinity of the light source can be surely prevented.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in some sidelight type surface light source devices applied to, for example, a liquid crystal display device, a part of a frame is made of metal so that the entire device can be reduced in weight and thickness. In such a sidelight type surface light source device, the metal member is configured to also serve as a primary light source reflector, thereby simplifying the overall configuration.
[0003]
That is, as shown in FIG. 6, the main part on the primary light source side is enlarged and shown, and this type of sidelight type surface light source device 1 has an end surface (hereinafter referred to as an incident surface) of the light guide plate 2 that is a transparent plate member. The illumination light L of the primary light source 3 is incident from 2A, propagates through the inside, and exits from the exit surface 2B of the light guide plate 2. The sidelight type surface light source device 1 corrects the characteristics of the illumination light L emitted from the emission surface 2B by various sheet materials arranged on the emission surface 2B, and the illumination light leaking from the back surface 2C of the light guide plate 2 is backside. The light is reflected by the reflection sheet 4 arranged at 2C and is incident on the light guide plate 2 again.
[0004]
The frame 5 includes a side plate that surrounds the light guide plate 2, various sheet materials, the primary light source 3, and the like, and a back side member that prevents the members from falling off to the back side. It consists of. When a part of the frame is made of metal, the frame 5 is made of, for example, a white resin that efficiently reflects illumination light, is formed by thin molding the frame body 5A, and the reinforcing material 5B is formed by bending a metal plate. The frame body 5A is disposed.
[0005]
In the frame 5, the strength of the frame body 5A is reinforced by the reinforcing material 5B, and the reinforcing material 5B is also used as a back side member. As a result, in this type of frame 5, the metal plate becomes a reinforcing material even if the entire frame is made thin as compared with the case where the frame is made of only resin, and this reinforcing material increases the strength of the member made of resin. It is reinforced and can be prevented from being deformed or damaged. As a result, in this type of sidelight type surface light source device, it is possible to reduce the overall weight and ensure sufficient strength as compared with the case of using an integrally molded frame made of resin. The thickness can be reduced.
[0006]
Further, in such a frame 5, the reinforcing member 5B is configured so as to also serve as a reflector of the primary light source, thereby simplifying the overall shape. The reflector is a regular reflection member or irregular reflection member disposed so as to surround the fluorescent lamp 6 that is a constituent member of the primary light source 3, and illuminates the illumination light L emitted in a direction other than the incident surface 2 </ b> A of the light guide plate 2. It is arranged to improve the utilization efficiency of the illumination light by reflecting to the lamp 6 side.
[0007]
In such a frame 5, the inner wall surface of the reinforcing member 5 </ b> B is generally in close contact with the emission surface 2 </ b> B of the light guide plate 2 on the emission surface side of the light guide plate 2, as shown partially enlarged by the arrow A. It is ideal that the illumination light is not incident on the light guide plate 2 from other than the incident surface 2A.
[0008]
[Problems to be solved by the invention]
By the way, in metal bending, it is difficult to manage the dimensions due to variations in the product shape due to the pressing force at the time of bending and the wear of the mold. Also, because the reflector itself is an elongated bent product that is almost the same length as the fluorescent lamp, when assembling the surface light source device, the reflector may be bent along the longitudinal direction depending on how it is handled. There is also.
[0009]
As a result, in this type of sidelight type surface light source device, light leakage and abnormal light emission occur in the vicinity of the light source, and the quality of the emitted light may be significantly reduced.
[0010]
That is, in the reflector 5B, as indicated by the arrow B, the inner wall surface of the reinforcing member 5B may not be in close contact with the emission surface 2B of the light guide plate 2 but may come into contact with the emission surface 2B at the leading edge. In this case, in the side light type surface light source device, a gap in which the illumination light of the primary light source wraps around the light exit surface 2B of the light guide plate 2 is formed between the incident surface 2A and the contacted portion.
[0011]
When such a gap is formed, in the sidelight type surface light source device, the illumination light that wraps around the gap enters the light guide plate 2 and is then reflected by the back surface 2C and emitted from the emission surface 2B. Thus, an abnormal light emission phenomenon in which the luminance level in the vicinity of the incident surface is partially increased is observed in the portion where the gap is generated in this way.
[0012]
In addition, as indicated by an arrow C, the inner wall surface of the reinforcing member 5B does not adhere to the exit surface of the light guide plate 2, and a gap is formed between the exit surface of the light guide plate 2 and the inner wall surface of the reinforcing member 5B. There is also.
[0013]
In this case, in addition to the phenomenon described for the arrow B, there also occurs a light leakage phenomenon in which the illumination light leaks directly from the gap to the exit surface 2B side.
[0014]
Further, although not particularly illustrated, when the reflector is curved or the like, the incident surface 2A side of the light guide plate 2 enters the reflector, and as a result, a part of the exit surface 2B of the light guide plate 2 is exposed in the reflector. There is also a problem that the illumination light is incident from the exposed portion and the luminance level in the vicinity of the incident surface is increased.
[0015]
The present invention has been made in consideration of the above points, and a sidelight type surface light source device capable of reliably preventing light leakage and abnormal light emission in the vicinity of the light source, and a liquid crystal using the sidelight type surface light source device. A display device is to be proposed.
[0016]
[Means for Solving the Problems]
  In order to solve such a problem, in the invention according to claim 1, the side light that enters the illumination light emitted from the predetermined light source from the incident surface of the light guide plate and bends the illumination light from the exit surface of the light guide plate. In the mold surface light source device,Surrounding the light source,A holding member that holds the light source is disposed opposite the incident surface of the light guide plate, and the holding member is formed by bending a metal plate material.Cross-sectional shapeFormed,One end of the holding member located on the exit surface side of the light guide plate in the opening by sandwiching the light guide plate by inserting the incident surface of the light guide plate into the substantially U-shaped opening. A slope is formed on the slope,Extending the exit surface to the light source sideThe ridgeline formed by the entrance surface and the exit surface of the light guide plate is in contact with the virtual plane obtained by this.
[0018]
  And claims2In the invention according to claim1In the above configuration, the holding member is a reflector that reflects the illumination light emitted from the light source.
[0019]
  And claims3In the invention which concerns on this invention, in the structure which concerns on Claim 1, a holding member is comprised as a part of flame | frame which hold | maintains a light-guide plate and another structural member integrally.
[0020]
  And claims4In the invention according to claim 1, claim 2Or claim 3The liquid crystal display panel is illuminated by the sidelight type surface light source device described in 1).
[0021]
  According to the configuration of claim 1, KeepThe holding member can be brought into close contact with the edge of the light guide plate to prevent generation of a gap that causes abnormal light emission, light leakage, and the like.
[0023]
  And claims2According to the configuration according to claim1In the configuration according to the present invention, the holding member is a reflector that reflects the illumination light emitted from the light source, so that even when the light guide plate is held by the reflector, the generation of a gap that causes abnormal light emission, light leakage, and the like is prevented. can do.
[0024]
  And claims3In the configuration according to claim 1, in the configuration according to claim 1, the holding member functions as a stopper of the light guide plate by making the holding member a part of the frame that integrally holds the light guide plate and the other constituent members. Therefore, the exit surface of the light guide plate is not exposed in the holding member, and abnormal light emission, light leakage, and the like can be prevented.
[0025]
  And claims4According to the configuration of claim 1, claim 1, claim2 or claim 3By illuminating the liquid crystal display panel with the sidelight type surface light source device described in 1), it is possible to prevent abnormal light emission and light leakage and display a high-quality image.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
[0027]
(1) First embodiment
FIG. 2 is an exploded perspective view showing the sidelight type surface light source device. The liquid crystal display device according to the first embodiment is assembled by arranging the sidelight type surface light source device on the back surface of the liquid crystal display panel, and the sidelight type surface light source device illuminates and displays the liquid crystal display panel. Form an image.
[0028]
Here, the sidelight type surface light source device 11 is assembled by sequentially disposing a reflection sheet 13, a light guide plate 14, a light diffusion sheet 17, prism sheets 15 and 16, and a protection sheet 18 on a frame 12 on which a primary light source is disposed. The reflection sheet 13 is composed of a sheet-like irregular reflection member made of a white PET film or the like, reflects the illumination light leaking from the back surface 14C of the light guide plate 14 and re-enters the light guide plate 14, thereby improving the use efficiency of the illumination light. improves.
[0029]
The light guide plate 14 is formed of a transparent member, for example, acrylic (PMMA resin) by injection molding and is formed in a wedge shape in cross section, and the illumination light of the primary light source is incident from the incident surface 14A. As a result, the light guide plate 14 repeatedly reflects the light between the exit surface 14B and the back surface 14C to propagate the illumination light. Upon reflection at the exit surface 14B and the back surface 14C, a component having a critical angle or less is transmitted. The light is emitted from the back surface 14C.
[0030]
Further, the light guide plate 14 is formed with a light scattering pattern that makes the back surface 14C locally rough and urges the emission of illumination light. Here, the light scattering pattern is formed by, for example, matte surface treatment, etching to a corresponding mold, or appropriate roughening treatment such as electric discharge machining, so that the back surface 14C is partially roughened by a rectangular shape, a circular shape, or other shapes. Formed.
[0031]
These light scattering patterns can be appropriately selected according to the area where the light scattering pattern occupies per unit area by changing the size of the individual light scattering patterns, the pitch at which the light scattering patterns are arranged, etc. Thus, the emitted light quantity of the illumination light emitted from the emission surface 14B is made uniform over the entire emission surface 14B. The light scattering pattern can also be formed on the exit surface 14B as necessary. In this case, it is preferable to form the light scattering pattern with a small diameter that is difficult to perceive from the exit surface side. Further, by changing the degree of roughness according to the portion of the light guide plate 14 instead of the light scattering pattern and making the entire surface of the back surface 14C rough, the amount of emitted light can be made uniform.
[0032]
Each of the prism sheets 15 and 16 has a prism surface formed on the surface opposite to the side facing the light guide plate 14, and corrects the directivity of illumination light emitted from the light guide plate 14 by the prism surface. These prism surfaces are formed by repeating protrusions having a triangular cross section extending substantially in one direction. In the prism sheet 15 on the light guide plate 14 side, these protrusions extend substantially parallel to the incident surface 14A of the light guide plate 14. As described above, the prism sheet 16 is formed so that the protrusion extends in a direction substantially orthogonal to the incident surface 14A. In addition, as a prism sheet, what is called a double-sided prism sheet of the structure which formed the prism surface on both surfaces may be used.
[0033]
The light diffusing sheet 17 scatters the illumination light emitted from the light guide plate 14 to make the emitted light amount uniform, and makes the brightness of the edge of the light guide plate 14 inconspicuous. The protection sheet 18 is a sheet material having weak light diffusibility, and protects the surface of the light diffusion sheet 17 from being damaged.
[0034]
The frame 12 is formed by screwing reinforcing members 21 and 22 to the frame body 20 with screws 19. Here, the frame body 20 is formed into a rectangular frame shape as shown in the figure by injection molding a white resin that efficiently reflects the illumination light. Each part of the frame body 20 is formed thinner than a case where the entire frame is integrally formed of resin, so that the weight of the side light type surface light source device 11 as a whole is reduced. The frame body 20 is formed with a collar 20A on the outer side surface, and reinforcing members 21 and 22 are screwed to the collar 20A, and further attached to the liquid crystal display panel via the collar 20A. Accordingly, the frame 12 constitutes a holding member that holds the constituent members of the sidelight type surface light source device 11 and also constitutes a part of a holding mechanism that holds the sidelight type surface light source device 11 on the back surface of the liquid crystal display panel. .
[0035]
In addition, the frame main body 20 protrudes inward on the back surface 14 </ b> C side of the light guide plate 14 on each side where the reinforcing members 21 and 22 are not disposed for the purpose of preventing the reflection sheet 13 from sagging. Thus, the protruding piece 20C is formed.
[0036]
The reinforcing members 21 and 22 are formed by bending a metal plate made of a lightweight metal such as stainless steel or aluminum, and along the frame body 20 on the side corresponding to the incident surface side and the wedge-shaped tip side of the light guide plate 14. It arrange | positions, this reinforces the intensity | strength of the frame main body 20, Furthermore, the deformation | transformation and damage of the frame main body 20 are prevented.
[0037]
That is, among these reinforcing members 21 and 22, the reinforcing member 21 disposed on the wedge-shaped front end side of the light guide plate 14 is formed by bending into a L-shaped cross section, and one end side rising to the L-shaped is the frame body. The other end side is formed so as to protrude inside the frame body 20 on the side corresponding to the back side of the light guide plate 14. Thereby, the reinforcing material 21 reinforces the strength of the frame body 20 to prevent the deformation and breakage of the side of the light guide plate 14 of the frame body 20 on the side of the wedge shape, and further reflects the reflection sheet 13 to the back surface side. It is designed to prevent the dropout. Note that the reinforcing member 21 disposed on the wedge-shaped front end side of the light guide plate 14 may be integrated with the frame body 20 by insert molding, thereby simplifying the frame assembling process.
[0038]
On the other hand, the reinforcing member 22 arranged on the incident surface 14A side functions as a holding member for holding the primary light source on the incident surface of the light guide plate 14 so as to function as a reflector in addition to these functions. Configured as follows.
[0039]
That is, as shown in FIG. 1, a cross-section taken along the line DD is shown in FIG. 1, the reinforcing member 22 is formed by bending a metal into a substantially U-shaped cross-section and disposed inside the frame body 20.
[0040]
A rubber bushing 23 having a prismatic shape is held inside both ends of the reinforcing material 22 (FIG. 2), and a fluorescent lamp 24 is disposed inside the reinforcing material 22 via the rubber bushing 23, and further the reinforcing material. It arrange | positions so that the opening side of 22 may become the entrance plane side of the light-guide plate 14. FIG. As a result, the reinforcing member 22 constitutes a reflector that reflects the illumination light emitted from the fluorescent lamp 24 and supplies the illumination light to the incident surface of the light guide plate 14, and constitutes a holding member for the fluorescent lamp 24. ing.
[0041]
That is, the rubber bushing 23 is formed so as to be elastically held inside the reinforcing member 22 by rubber which is an elastic member. Further, the rubber bushing 23 is formed with an insertion hole into which the fluorescent lamp 24 is inserted, and a lead-out port for drawing out a lead wire connected to the electrode 24A of the fluorescent lamp 24 from the insertion hole, whereby the fluorescent lamp 24 is inserted into the insertion hole. The lead wire is pulled out from the outlet and is held inside the reinforcing member 22, so that the fluorescent lamp 24 can be arranged inside the reinforcing member 22.
[0042]
Thus, when the fluorescent lamp 24 is disposed on the reinforcing member 22, the rubber bushing 23 is configured such that the portion of the electrode 24A that is not used for emitting the illumination light in the fluorescent lamp 24 is inserted into the insertion hole. The fluorescent lamp 24 is held by the reinforcing material 22 at both end portions on the incident surface 14A side. Accordingly, the rubber bushing 23 constitutes a holding member that holds the fluorescent lamp 24 on the reinforcing member 22 that is a reflector, and also constitutes a buffer member that buffers an impact on the fluorescent lamp 24, and further, a reinforcing member 22 made of metal. And an insulating member that insulates the electrode 24A. In the fluorescent lamp 24, the connecting portion of the lead wire is covered with the electrode 24A by a heat shrinkable tube and inserted into the rubber bushing 23, whereby the rubber bushing 23 is the heat shrinkable tube in this embodiment. Together with the insulating member.
[0043]
The reinforcing member 22 is formed such that one end side on the emission surface 14B side is bent inwardly at a substantially right angle in a stepwise manner, so that the rubber bushing 23 is held so as not to be displaced to the light guide plate 14 side. Has been made. As a result, the reinforcing member 22 also serves as a holding member that holds the primary light source.
[0044]
The reinforcing member 22 is set at a location where the inward bending is deeper on the light source side than the incident surface 14A of the light guide plate 14 and the bending angle is approximately 90 degrees as shown by an enlarged reference E. It is designed to be set. Further, the reinforcing member 22 is folded back at an angle larger than 90 degrees at a position on the back surface 14C side by a minute distance from the exit surface 14B side edge of the incident surface 14A.
[0045]
That is, one end of the reinforcing member 22 located on the light exit surface 14B side of the light guide plate 14 is a portion that is closer to the light source than the light entrance surface 14A of the light guide plate 14 when the surface light source device is assembled. Further, the tip end side is folded back in the direction away from the light source, and the angle formed by the hanging piece shown by 22B in the figure and the folded piece shown by 22C in the figure is less than 90 degrees, and the hanging piece 22B The connecting portion 22D with the folded piece 22C is configured to be positioned below the light exit surface 14B of the light guide plate 14 (on the back surface 14C side).
[0046]
As a result, one end side of the reinforcing member 22 straddles the emission surface 14B side edge E so as to come into contact with the emission surface 14B side edge of the light guide plate 14 and away from the emission surface 14B as the distance from the light source increases. An inclined surface 22A is formed on the surface.
[0047]
The reinforcing member 22 is configured to sandwich the reflection sheet 13 and the light guide plate 14 between the inclined surface 22A and the front end side on the back surface 14C opposite to the inclined surface 22A. The primary light source is held on the incident surface 14A of the light guide plate 14 by preventing vertical rattling, and the inclined surface 22A functions as a stopper so that the light guide plate 14 hangs down and connects the connecting portion 22D between the piece 22B and the folded piece 22C. Do not move beyond the fluorescent lamp 24 side. Thus, abnormal light emission that occurs when illumination light enters the light guide plate 14 from other than the incident surface 14A of the light guide plate 14 is prevented.
[0048]
Here, as shown by the broken line in FIG. 3, the reinforcing material 22 is formed so that the front end of the reinforcing member 22 falls inward on the back surface 14 </ b> C side. 13 and the light guide plate 14 are sandwiched.
[0049]
Accordingly, in this embodiment, the protective sheet 18 emits light so as to straddle the light emitting plate 14 side tip of the light emitting plate 14 and the light emitting plate 14 on the light emitting plate 14 side end of the reinforcing member 22 that is bent in this manner. An edge 18A is formed by adhering black paint on the opposite side of the surface on the surface 14B side, thereby ensuring prevention of light leakage and abnormal light emission.
[0050]
(1-2) Operation of the first embodiment
In the above-described configuration, the sidelight type surface light source device 11 (FIGS. 1 and 2) has a frame body 20 formed by injection molding a white resin. The reinforcing member 21 is attached by the screw 19, and thereby the frame main body 20 is formed thin with sufficient strength to prevent deformation and breakage of the frame main body 20 on the wedge-shaped tip side.
[0051]
Further, on the incident surface 14A side of the light guide plate 14, the fluorescent lamp 24 and the fluorescent lamp 24 are placed inside the reinforcing member 22 in a state where both end electrodes 24A of the fluorescent lamp 24 are inserted into the insertion holes of the rubber bushing 23 and lead wires are drawn out from the outlet. A rubber bushing 23 is disposed, and the reinforcing member 22 is attached to the frame main body 20 with screws 19. Thereby, in the side light type surface light source device 11, sufficient strength is secured on the incident surface 14A side of the light guide plate 14 so that deformation and breakage of the frame body 20 can be prevented, and the frame body 20 is thin. Formed.
[0052]
At this time, in the sidelight type surface light source device 11, the reinforcement members 21 and 22 are bent so that the reinforcement members 21 and 22 have a function of preventing the reflection sheet 13 and the like from falling to the back surface 14 </ b> C side. The thickness of the back surface 14C side of the light guide plate 14 is made thinner as compared with the case where this drop-off preventing mechanism is formed by a resin member, that is, when the frame is formed by integral molding of the resin. Thus, the thickness of the entire frame can be reduced accordingly.
[0053]
On the incident surface 14A side, the reinforcing member 22 is bent so as to surround the fluorescent lamp 24, and the reinforcing member 22 is also used as a reflector of the light source. As compared with the case where a reflector is separately arranged, the configuration can be simplified, and the overall thickness can be reduced.
[0054]
When the fluorescent lamp 24 is held in this manner, in the sidelight type surface light source device 11, the exit surface 14B side of the reinforcing member 22 is bent in a step shape, and the rubber bushing 23 is caught on the bent portion. As a result, the displacement of the fluorescent lamp 24 toward the light guide plate 14 is prevented. Further, even if some impact is applied to the reinforcing member 22, the impact on the fluorescent lamp 24 is mitigated by the elasticity of the rubber bushing 23, thereby preventing the fluorescent lamp 24 from being damaged. Moreover, even when the electrode periphery of the fluorescent lamp 24 is insulated by the rubber bushing 23 and the heat shrinkable tube, and the reflector is constituted by the reinforcing material 22 made of a metal material in this way, the fluorescent lamp 24 can be stably lit. Become.
[0055]
Further, in the sidelight type surface light source device 11, the light source extends from the light source across the exit surface 14B side edge of the entrance surface 14A to the exit surface 14B side portion of the reinforcing member 22 that prevents the displacement of the rubber bushing 23 in this way. A slope 22A is formed so as to be farther from the exit surface 14B as the distance is increased, and the light guide plate 14 and the reflection sheet 13 are provided with the reinforcing material 22 such that the edge E on the exit surface 14B side of the entrance surface 14A of the light guide plate 14 abuts the slope 22A. Held by.
[0056]
Thereby, in the side light type surface light source device 11, even when the finish of the reinforcing material 22 varies, the generation of a gap between the light guide plate 14 and the reflector is prevented, and the illumination light leaks from the gap. Can be prevented from leaking light.
[0057]
Further, since the reinforcing plate 22 as a reflector is in contact with the edge E on the exit surface 14B side of the light guide plate 14, it is possible to prevent the illumination light from wrapping around from the exit surface 14B side, thereby preventing abnormal light emission. can do.
[0058]
That is, as described above with reference to FIG. 6, in the configuration in which the metal plate is bent at 90 degrees and the front end side of the reflector 5 </ b> B is in close contact with the exit surface 2 </ b> B of the light guide plate 2, the angle of the bent portion is slightly However, if it varies, a gap is formed so that the illumination light wraps around the light guide plate from the exit surface side, as indicated by reference numeral B. Similarly, a gap for light leakage is formed between the exit surface 2B of the light guide plate 2 and the reflector 5B, as indicated by reference numeral C because the force of clamping from the reflection sheet side is weakened.
[0059]
However, as in this embodiment, if the edge E of the light guide plate 14 is pressed against the slope 22A extending across the edge of the light guide plate 14, light leakage, even if the slope of the slope 22E slightly changes, Generation of gaps that cause abnormal emission can be prevented.
[0060]
Further, in the sidelight type surface light source device 11, when the light guide plate 14 is displaced to the light source side due to an impact or the like, the edge E pushes up the inclined surface 22A, and the reinforcing member 22 resists this pushing force. Then, the edge E of the light guide plate 14 is pressed. Thereby, in the sidelight type surface light source device 11, the inclined surface 22A can prevent the light guide plate 14 from being displaced toward the light source side, and the fluorescent lamp 24 can be reliably prevented from being damaged.
[0061]
Furthermore, in the case where the reinforcing member 22 is folded at an angle larger than 90 degrees as described above, the reinforcing member 22 can also prevent deformation due to handling after processing as compared with the case of folding back at 90 degrees. Light leakage can be prevented.
[0062]
(1-3) Effects of the first embodiment
According to the above configuration, the portion on the exit surface 14B side of the reinforcing material 22 is folded back more than 90 degrees on the back surface 14C side from the exit side edge E of the light guide plate 14, and straddles the exit surface 14B side edge E of the entrance surface 14A. The inclined surface 22A is formed so as to be further away from the back surface 14C as the distance from the light source is increased, and the emission surface 14B side edge E of the light guide plate 14 is pressed against the inclined surface 22A, whereby a part of the frame is made of metal and has an overall shape. Even in the case of reducing the thickness, light leakage and abnormal light emission can be surely prevented.
[0063]
(2) Second embodiment
FIG. 4 is a cross-sectional view showing a partially enlarged side light type surface light source device according to the second embodiment of the present invention in comparison with FIG. The sidelight type surface light source device according to this embodiment is configured in the same manner as in the first embodiment except that the configuration of the reinforcing member 32 shown in FIG. 4 is different.
[0064]
Here, the reinforcing member 32 is configured in the same manner as the reinforcing member 22 described above with respect to the first embodiment except that the inward bending is formed at an angle greater than 90 degrees on the emission surface 14B side. .
[0065]
As a result, in the sidelight type surface light source device according to this embodiment, even when the finish of the reinforcing material varies in the inwardly bent portion, the same effect as in the first embodiment can be obtained. The strength of the reinforcing member 32 is further increased.
[0066]
(3)Reference example
  FIG. 5 shows the present invention by comparison with FIG.Reference examples not included inIt is the top view and sectional drawing which show the sidelight type surface light source device which concerns on. In the sidelight type surface light source device 41 according to this embodiment, a frame 42 is formed by molding a white resin, and the frame 42 also serves as a reflector.
[0067]
In other words, in the side light type surface light source device 41, the frame 42 is configured to have a U-shaped cross section so that the fluorescent lamp 24 is held inside. On the exit surface 14B side, the inner wall surface of the frame 42 is formed by the inclined surface 42A so as to straddle the exit surface 14B side edge E of the entrance surface 14A and away from the back surface 14C as the distance from the light source increases. The frame 42 is configured such that the light guide plate 14 is pressed toward the fluorescent lamp 24 by a pressing member (not shown) in a state where the light guide plate 14 and the reflection sheet 13 are integrally inserted into the U-shaped recess. Thus, the light guide plate 14 and the reflection sheet 13 are held.
[0068]
As shown in FIG. 5, even when the light source is held on the incident surface of the light guide plate by the frame, it straddles the emission surface 14B side edge E of the incident surface 14A, and moves away from the back surface 14C as the distance from the light source increases. By forming the inclined surface 42A on the inner wall surface, the same effect as in the first embodiment can be obtained.
[0070]
(4) Other embodiments
  In additionIn the above-described embodiment, the case where the inclined surface is formed only on the emission surface side has been described. However, the present invention is not limited to this, and the inclined surface may be formed symmetrically on the back surface side. If it does in this way, it can also comprise so that a light-guide plate may be pressed on the light source side, and the edge of a light-guide plate may be pressed on the slope by the side of an output surface with the back surface side slope.
[0071]
Further, in the above-described embodiment, the case where a prism sheet, a protective sheet, and the like are disposed on the light exit surface of the light guide plate has been described. However, the present invention is not limited thereto, and when various sheet materials are disposed, the guide is further introduced. The present invention can be widely applied in the case where the arrangement of the sheet material is omitted by forming a prism surface similar to the prism sheet on the exit surface or the back surface of the optical plate and incorporating the function of the prism sheet in the light guide plate.
[0072]
Moreover, in the above-mentioned embodiment, although the case where the light guide plate is constituted by the transparent resin has been described, the present invention is not limited to this, and the transparent resin constituting the light guide plate is made of a resin material having a refractive index different from that. The present invention can be widely applied to the case where a light guide plate is configured by mixing fine particles.
[0073]
Further, in the above-described embodiment, the case where the side light type surface light source device is configured by the light guide plate having a wedge-shaped cross section has been described. However, the present invention is not limited thereto, and the side light type surface is formed by the flat light guide plate. The present invention can be widely applied to the configuration of a light source device.
[0074]
In the above-described embodiment, the case where the side light type surface light source device is configured by using one of the four side surfaces of the light guide plate as the incident surface is described. However, the present invention is not limited to this. Also, the present invention can be widely applied to configurations in which other side surfaces are used together as an incident surface.
[0075]
Further, in the above-described embodiment, the case where the liquid crystal display panel is illuminated by the sidelight type surface light source device has been described. However, the present invention is not limited to this and is widely applied to the case where illumination light is provided to various devices. be able to.
[0076]
【The invention's effect】
As described above, according to the present invention, the slope is formed so as to be farther from the exit surface of the light guide plate as it is farther from the light source so as to straddle the exit surface side edge of the entrance surface. By pressing against the light, it is possible to reliably prevent light leakage and abnormal light emission in the vicinity of the incident surface.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view showing a light source side of a sidelight type surface light source device according to a first embodiment of the present invention.
2 is an exploded perspective view showing the side light type surface light source device of FIG. 1; FIG.
3 is a cross-sectional view showing a reinforcing material applied to the sidelight type surface light source device of FIG. 1. FIG.
FIG. 4 is an enlarged cross-sectional view showing a side light type surface light source device according to a second embodiment of the present invention in comparison with FIG.
FIG. 5 shows a comparison of FIG.Reference exampleIt is sectional drawing which expands and shows the sidelight type surface light source device which concerns on.
FIG. 6 is an enlarged sectional view showing a light source side of a conventional sidelight type surface light source device.
[Explanation of symbols]
  1, 11, 41: side light type surface light source device, 2, 14: light guide plate, 5, 12, 32: frame, 5A, 20A: frame main body, 5B, 22: reinforcing material, 6, 24 …… Fluorescent lamp, 23 …… Rubber bushing

Claims (4)

In the sidelight type surface light source device that enters the illumination light emitted from the predetermined light source from the incident surface of the light guide plate, bends the illumination light and emits the light from the exit surface of the light guide plate,
Surrounding the light source, arranging a holding member for holding the light source so as to face the incident surface of the light guide plate,
The holding member is
It is formed into a substantially U-shaped cross section by bending a metal plate material,
The light guide plate is sandwiched by inserting the incident surface of the light guide plate into the substantially U-shaped opening,
A slope is formed at one end of the holding member located on the light exit surface side of the light guide plate in the opening,
The slope is
While being formed so as to cross a virtual plane obtained by extending the emission surface to the light source side ,
A side light type surface light source device characterized in that a ridge formed by the incident surface and the exit surface of the light guide plate is in contact . The holding member is
It is a reflector which reflects the illumination light radiate | emitted from the said light source. The sidelight type surface light source device of Claim 1 characterized by the above-mentioned. The holding member is
The side light type surface light source device according to claim 1, wherein a part of a frame that integrally holds the light guide plate and the other constituent members is configured. A liquid crystal display device illuminates a liquid crystal display panel with the sidelight type surface light source device according to claim 1, claim 2 or claim 3.

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