JP4912230B2 - Surface emitting device and electronic device - Google Patents

Description

  The present invention relates to a surface light emitting device that is disposed on the back side of a liquid crystal panel or the like and that irradiates the liquid crystal panel from the back side.

  2. Description of the Related Art Conventionally, as a surface light emitting device disposed on the back surface of a liquid crystal panel, a side light type device that guides light to the surface side of a light guide plate with a side surface of the light guide plate as a light incident surface is known (for example, Patent Document 1).

For example, as shown in FIG. 9, the sidelight type surface light emitting device 1 includes a light emitting diode (LED) 4 connected to a flexible substrate (Flexible Printed Circuit: hereinafter referred to as FPC) 3 in a holder 2. The side surface of the light guide plate 5 is arranged to face the LED 4. The light guide plate 5 is configured to guide the light incident from the side surface to the front surface side and irradiate the liquid crystal panel connected via the rim sheet 6 on the light guide plate 5.
JP 2004-177890 A

  In such a surface light-emitting device, it is considered that light from an LED to be mounted is emitted from the surface of the light guide plate as efficiently as possible.

  However, in the configuration of the conventional surface light emitting device, when forming a surface light emitting device with high light use efficiency, the LED mounted on the FPC is considered with respect to the side surface of the light guide plate in consideration of the light incident efficiency. Therefore, it is necessary to position and arrange the optical axes so that they are orthogonal to each other.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a surface light-emitting device with high light utilization efficiency with a simple configuration without positioning a light-emitting element with respect to a light guide plate.

A surface light emitting device according to an aspect of the present invention is provided on a light guide plate, a light emitting element provided on an outer periphery of the light guide plate, and a surface on which the light emitting element is disposed, and forms a wiring of the light emitting element. A conductive film portion having a light-shielding property ; and a holder including a frame body that accommodates the light guide plate in which the light emitting element and the conductive film portion are provided. On the inner peripheral surface corresponding to the outer shape, a notch portion for accommodating the light emitting element is formed at a position corresponding to the position of the light emitting element attached to the light guide plate, and the inner wall surface of the notch portion is incident light. The conductive film portion and the light emitting element are electrically connected to a portion of the outer peripheral surface of the light guide plate facing the notch portion, and the light guide plate is more than the conductive film portion. The electrode part having a short length in the thickness direction is disposed. A configuration that.
The surface light-emitting device according to one aspect of the present invention includes a light guide plate, a light-emitting element provided on an outer periphery of the light guide plate, and a surface on which the light-emitting element is arranged to form a wiring of the light-emitting element. And having a light shielding plate and a holder having a frame for accommodating the light guide plate provided with the light emitting element and the conductive film, the frame including the light guide plate. On the inner peripheral surface corresponding to the outer shape of the optical plate, a notch portion for accommodating the light emitting element is formed at a position corresponding to the position of the light emitting element attached to the light guide plate, and the inner wall surface of the notch portion is made incident. A transparent electrode portion that reflects light transmitted to the light guide plate and electrically connects the conductive film portion and the light emitting element to a portion facing the notch portion on the outer peripheral surface of the light guide plate. The arrangement | positioning arrange | positioned is taken.
The surface light-emitting device according to one aspect of the present invention includes a light guide plate, a light-emitting element provided on an outer periphery of the light guide plate, and a surface on which the light-emitting element is arranged to form a wiring of the light-emitting element. And having a light shielding plate and a holder having a frame for accommodating the light guide plate provided with the light emitting element and the conductive film, the frame including the light guide plate. On the inner peripheral surface corresponding to the outer shape of the optical plate, a notch portion for accommodating the light emitting element is formed at a position corresponding to the position of the light emitting element attached to the light guide plate, and the inner wall surface of the notch portion is made incident. The conductive film portion and the light emitting element are electrically connected to the front and back surfaces of the light guide plate adjacent to the portion facing the notch portion on the outer peripheral surface of the light guide plate. The structure which the electrode part to perform is arrange | positioned is taken.

  As described above, according to the present invention, it is possible to increase the light use efficiency, improve the brightness efficiency, and improve the brightness uniformity with a simple configuration without positioning the light emitting element with respect to the light guide plate. it can.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram for explaining the surface light-emitting device according to Embodiment 1 of the present invention, and is a diagram illustrating a main part of a configuration of an electronic device including the surface light-emitting device.

  In the electronic device 100 shown in FIG. 1, a surface light emitting device 200 that irradiates the liquid crystal panel 110 from the back surface is disposed on the back surface of the liquid crystal panel 110. The liquid crystal panel 110 includes an FPC 113, a driver IC 114 for driving a liquid crystal, and a glass substrate 116 with a polarizing plate 115 attached to a surface portion serving as a display area on the surface of a glass substrate 112 with a polarizing plate 111 attached to the back surface. Installed. The liquid crystal panel 110 has a transmissive or transflective pixel structure.

  The surface light emitting device 200 includes a holder 210 formed in a box shape, a reflection sheet 220, a light emitting diode (hereinafter referred to as “LED”) 230 that is a light emitting element, a light guide plate 240, and a conductive film portion 250. The light guide plate unit 260, the diffusion sheet 222, the light collecting sheets 223 and 224, and the rim sheet 225 are included.

  The surface light emitting device 200 is connected to the back surface of the liquid crystal panel 110 via a rim sheet 225. The rim sheet 225 is a double-sided pressure-sensitive adhesive tape having a light shielding property, and has a window frame shape so that emitted light from the surface light emitting device 200 irradiates only an effective display area (an area where an image is displayed) of the liquid crystal panel 110. ing.

  A reflection sheet 220 is disposed on the bottom surface of the holder 210, and a light guide plate unit 260, a diffusion sheet 222, light collection sheets 223 and 224, and a rim sheet 225 are sequentially stacked on the reflection sheet 220.

  The reflection sheet 220 reflects incident light to the surface side, and here, reflects light emitted from the light guide plate unit 260 disposed on the upper surface to the surface side of the light guide plate 240. In the light guide plate 240, the area within the window frame of the rim sheet 225 is an effective light emitting area on the surface covered with the diffusion sheet 222 and the light collecting sheets 223 and 224.

  FIG. 2 is a schematic diagram for explaining a main configuration of the light guide plate unit.

  In the light guide plate unit 260, the LED 230 is attached to one side surface 242 of the outer peripheral surface of the light guide plate 240 having a planar shape and having an end surface as a light incident surface, with its optical axis orthogonal to one side surface.

  Here, the light guide plate 240 has a rectangular plate shape. For example, the light guide plate 240 is formed of a light guide member such as an acrylic resin plate, and the side surface is formed by a light guide pattern formed on the back surface or both the front surface and the back surface. Is incident on the surface side. A plurality of LEDs 230 are attached to one side surface 242 of the light guide plate 240 side by side at a predetermined interval.

  The LED 230 is attached to the light guide plate 240 in a state where the light emitting surface is opposed to the portion 242a of the one side surface 242 of the light guide plate 240, and emits light to the light guide plate 240 when light is emitted. In the present embodiment, the LED 230 has a rectangular light emitting surface, and light is emitted directly from the light emitting surface to the light guide plate 240, so that the light guide plate 240 is orthogonal to the mounting surface of the LED 230. (Surface side) is irradiated with light.

  Thus, the outer peripheral surface 243 of the light guide plate 240 to which the LED 230 is attached is provided with a conductive film portion 250 having conductivity and serving as the wiring of the LED 230.

  The conductive film portion 250 is formed in a belt shape having substantially the same width as the thickness of the light guide plate 240 and is provided so as to cover the portion of the outer peripheral surface (side surface) of the light guide plate 240 to be attached. Here, the conductive film portion 250 is attached to a side portion of the light guide plate 240 provided in close contact so that no air layer exists between the conductive portion 250 and the portion.

  Note that the conductive film portion 250 may be formed on the side surface of the light guide plate 240 by plating, applying a conductive paint, or printing, or may be formed by sticking, vapor deposition, or adhesion of a conductive film material. Also good.

  Here, the conductive film part 250 is made of a light-shielding metal film, and includes a first light-shielding conductive film part 251, a second light-shielding conductive film part 252 attached to one side 242 of the light guide plate 240 to which the LED is attached, It has the 3rd light-shielding conductive film part 253 and the 4th light-shielding conductive film part 254, and the 5th light-shielding conductive film part 255 attached to the side surface except the one side 242 following the 4th light-shielding conductive film part 254.

  The first light-shielding conductive film portion 251 is connected to the FPC 280 by solder 270 at one end 251a and is connected to the terminal of the LED 230-1 by bonding at the other end 251b. The second light-shielding conductive film portion 252 is disposed between the LED 230-1 and the LED 230-2, and is connected to the terminals of the LEDs 230-1 and 230-2 by bonding at both ends 252a and 252b. The third light-shielding conductive film portion 253 is disposed between the LED 230-2 and the LED 230-3, and is connected to the terminals of the LEDs 230-2 and 230-3 by bonding at both ends 253a and 253b.

  The fourth light-shielding conductive film portion 254 is attached between the LED 230-3 and the corner portion 240a of the light guide plate 240, and is connected to the terminal of the LED 230-3 by bonding at one end portion 254a on the LED 203-3 side, and the other end. The portion 254b is connected to one end portion 255a of the fifth light-shielding conductive film portion 255.

  The fifth light-shielding conductive film portion 255 is attached so as to cover three side surfaces other than the one end surface 242 on the outer peripheral surface 243 of the light guide plate 240, and the other end portion 252 b is connected to the one end portion 251 a of the first light-shielding conductive film portion 251. The FPC 280 is connected to the FPC 280 by solder 270.

  In other words, the conductive films 250 (251 to 255) are mounted on the light guide plate 240 by bonding the LEDs 230-1 to 230-3 to the conductive films 251 to 254 attached to the side surface 242 of the light guide plate 240 by bonding. LED 230-1 to 230-3 are electrically connected in series to form a wiring portion of the LED 230 surrounding the light guide plate 240.

  Here, the FPC 280 is disposed below the corner portion 240b formed by one end portion of one side surface 242 to which the LED 230 is attached in the light guide plate 240, and the first light shielding conductive film portion 251 and the fifth light shielding conductive film portion. However, the FPC 280 and the conductive film portion 250 may be connected at any position on the outer periphery of the light guide plate 240 to which the conductive film portion 250 is attached. For example, the first light-shielding conductive film portion 251 and the fifth light-shielding film 255 are connected, and the FPC 280 is disposed below the side surface adjacent to one side surface, and the light-shielding conductive film portion positioned above is spaced apart in the longitudinal direction. Thus, the divided pieces may be connected as anode terminals and cathode terminals, respectively.

  In the light guide plate unit 260 to which the FPC 280 is connected, a current flows from the FPC 280 to the LED 230 through the conductive film portion 250 and light is emitted. Light from the LED 230 directly enters the light guide plate 240 from one side of the light guide plate 240 and is shielded by the conductive film portion 250, and is guided by the light guide pattern formed on the light guide plate 240, the reflective sheet 220, and the like. The light is emitted from the surface side of 240. Note that the holder 210 (see FIG. 1) also shields light leaking from the back surface of the light guide plate unit 260 and returns it to the front surface side of the light guide plate unit 260.

  Then, the light is diffused by the diffusion sheet 222 (see FIG. 1) on the upper surface of the light guide plate unit 260, and the liquid crystal panel 110 is irradiated from the back via the light collecting sheets 223 and 224.

  According to this configuration, the LED 230 is attached to the light guide plate 240, and the conductive film portion 250 serving as a wiring directly connecting the LED 230 is attached to the outer periphery of the light guide plate 240. For this reason, when forming the surface light-emitting device 200, it is not necessary to position the LED with respect to the light guide plate 240, and it is not necessary to separately provide an installation area of a wiring portion for connecting the LEDs.

  In other words, unlike the conventional case, the LED mounted on the FPC does not need a positioning operation for accurately performing the light incident efficiency with respect to the light guide plate 240, which is a member different from the LED, and has a simple configuration and light. Can be used efficiently, and a surface light emitting device with high luminance can be easily formed.

  In addition, the outer peripheral surface 243 of the light guide plate 240 is covered with a closely contacted conductive film portion (first to fifth light shielding conductive film portions). For this reason, the conductive film part 250 can prevent light leakage from the end face of the light guide plate 240 and increase the light use efficiency in the light guide plate 240, and can effectively guide the light from the LED to the surface side. It can emit light and emit light on the surface side. That is, it is possible to improve luminance efficiency and luminance uniformity in the light guide plate 240.

  In addition, the conductive film portion 250 is attached to the side portion of the light guide plate 240 to be attached so that there is no air layer between the conductive portion 250 and the portion. For this reason, light leakage from the end face of the light guide plate 240 is further prevented, and the light use efficiency in the light guide plate 240 can be improved. Furthermore, by forming the conductive film portion 250 with a material having a metallic luster, not only leakage of light from the end surface of the light guide plate 240 is prevented, but also light can be actively reflected and returned to the inside of the light guide plate. This can further improve the light utilization efficiency.

  In the present embodiment, the LED is attached to one side 242 of the outer peripheral surface 243 of the light guide plate 240. However, the present invention is not limited to this, and the configuration may be such that the entire outer peripheral surface 243 is mounted apart from each other. Good.

(Embodiment 2)
FIG. 3 is a plan view of the surface light emitting device for explaining the surface light emitting device according to Embodiment 2 of the present invention, and FIG. 4 is a diagram showing a light guide plate unit that is a main part of the surface light emitting device. is there.

  The surface light emitting device 300 according to the second embodiment is different from the surface light emitting device 200 according to the first embodiment shown in FIG. 1 in the light guide plate unit 360 and the box-shaped holder 310 that houses the light guide plate unit 360. Only the configuration of the inner peripheral wall portion is different, and the other configurations have the same configuration. Therefore, only different configurations will be described, and similar configurations will be given the same names and reference numerals, and descriptions thereof will be omitted.

  3 is disposed on the back surface of the liquid crystal panel 110 (see FIG. 1) and irradiates the liquid crystal panel (see FIG. 1) from the back surface. The light guide plate unit 260 according to the first embodiment. The light guide plate unit 360 having the same basic configuration as that shown in FIG.

  First, the light guide plate unit 360 will be described.

  A light guide plate unit 360 illustrated in FIG. 4 includes an LED 230 that is a light emitting element, a light guide plate 240, and a conductive film portion 350. Although not shown, a diffusion sheet, a light collecting sheet, and a rim sheet are stacked on the front surface side of the light guide plate unit 360, and are joined to the back surface of the liquid crystal panel via the rim sheet.

  The light guide plate unit 360 is different from the light guide plate unit 260 of the first embodiment in that the LED 230 is attached to one side surface 242 in the light guide plate unit 260, whereas the LED 230 is attached to the outer peripheral surface 243 of the light guide plate 240. They are attached at predetermined intervals over the entire circumference, and are electrically connected in series by a light-shielding conductive film portion 350 configured in the same manner as the conductive film portion 250.

  That is, the light guide plate unit 360 has a plurality of LEDs 230 mounted on the side surfaces 244 and 245 adjacent to the one side surface 242 and the side surface 246 parallel to the one side surface 242 on the outer peripheral surface 243 of the light guide plate 240. The conductive film portion 350 (corresponding to the fifth light-shielding film portion) provided is electrically connected in series by the divided pieces 350a to 350k.

  Note that the LED 230 and the conductive film portion 350 are provided on the light guide plate 240 in the same manner as the LED 230 and the conductive film portion 250 of the first embodiment, and a description thereof will be omitted.

  The light guide plate unit 360 configured as described above is accommodated in the frame 312 of the holder 310. Here, the holder 310 has a box shape having a frame 312 surrounding the light guide plate unit 360 from the side as a peripheral wall portion, and a reflection sheet (not shown) is laid on the bottom surface.

  In the holder 310, the peripheral wall portion as the frame body 312 has an inner peripheral surface 314 corresponding to the outer shape of the light guide plate 240 of the light guide plate unit 360, and the LED 230 attached to the light guide plate 240 on the inner peripheral surface 314. A notch 320 that accommodates the LED 230 is formed at a position corresponding to the position.

  That is, the peripheral wall portion as the frame body 312 in the holder 310 is formed corresponding to the side surface shape of the light guide plate unit 360 itself.

  The notch 320 is formed to open upward and toward the light guide plate unit 360 accommodated in the holder 310, and the inner wall surface 322 reflects incident light to the light guide plate 240 side.

  Here, the notch 320 is formed by notching the inner peripheral surface 322 in a circular arc shape in plan view. The inner wall surface 322 is a curved surface surrounding the LED 230. The curved inner wall surface 322 reflects light leaking from the emitted LED 230 to the notch 320 side and reflects to the light guide plate 240 side facing the inner wall 322 of the notch 320.

  Thereby, the light leaked from the LED 230 to the notch 320 side into the light guide plate 240 through the end surface portion exposed between the portion where the LED 230 is attached on the side surface of the light guide plate 240 and the front and back surfaces of the light guide plate 240. Incident light can improve the light use efficiency in the light guide plate 240. Therefore, it is possible to improve the luminance efficiency and the luminance uniformity of the light emitted from the light guide plate 240 by driving the LED 230, specifically, the light irradiating the liquid crystal panel.

  According to the surface light emitting device 300 including the light guide plate unit 360 housed in such a holder 310, the use efficiency of light by the conductive film portion 350 is improved and the positioning of the LED with respect to the light guide plate 240 when the surface light emitting device is configured. In the light guide plate unit, the LEDs are arranged on the four side surfaces, which are the entire circumference of the light guide plate 240, respectively. Thus, the light emitted from the surface side can be emitted uniformly.

  Further, in the configuration in which the LEDs 230 are attached over the entire circumference of the light guide plate 240, the wiring of the LEDs 230 is configured by a conductive film portion 350 provided on the outer periphery of the light guide plate 240.

  For this reason, the complicated wiring for making all the LEDs 230 emit light is not used. That is, in the surface light emitting device 300 including the light guide plate unit 360, the outer peripheral surface 243 of the light guide plate 240 is disposed outside the light guide plate 240 in the holder 310 that houses the light guide plate unit 360. Therefore, it is not necessary to arrange a complicated FPC that becomes the wiring of the LED 230 attached to the entire surface, and space saving can be achieved.

  Here, the notch 320 of the holder 310 is formed so as to open on the side of the light guide plate unit 360 accommodated in the holder 310 and on the upper side. However, the reflective sheet covers the upper opening. (For example, the same material as the reflection sheet 220) may be laid. By doing so, light leaking from the upper opening can be reflected to the light guide plate 240 side, and the light utilization efficiency can be further improved.

  In Embodiment 2, when light leaking from the LED 230 to the notch portion side is reflected by the notch portion 320 to the light guide plate 240 side, a region where a part of the conductive film portion 350 is attached to the side surface portion facing the notch portion 320 The side surface of the light guide plate 240 may be used as a light incident surface.

  This configuration will be described as a modification of the surface light emitting device in the second embodiment. Note that. The light guide plate units shown in the following modifications have the same basic components.

(Modification 1)
FIG. 5 is a diagram for explaining a first modification of the surface light emitting device according to the second embodiment.

  In the surface light emitting device 400 shown in FIG. 5, an LED 230 and a conductive film portion 450 having a light shielding property and a conductivity serving as a wiring of the LED 230 are provided on one side surface 242 of the light guide plate 240 of the light guide plate unit 460. Yes.

  The conductive film portion 450 is attached to one side 242 of the light guide plate 240 in a portion adjacent to the LED 230 in the longitudinal direction, and corresponds to the thickness of the light guide plate 240 (the length between the front and back surfaces) and is substantially the same as the thickness. Divided conductive film portions 451 to 453 having a width, and electrode portions 454 to 457 connecting the divided conductive film portions 451 to 453 and the side end portions of the LED 230 are provided.

  The divided conductive film portions 451 to 453 are disposed to face the inner peripheral surface 314 of the holder 310, and the end portions 451a, 452a, and 453a on the LED side of the divided conductive film portions 451 to 453 are each concave (here, arc-shaped). ) Of the notch 320 is disposed at a position facing both end edges 320a.

  The width of the electrode portions 454 to 457 (the length in the thickness direction of the light guide plate 240) is shorter than the width of the divided conductive film portions 451 to 453. Here, it is shorter than the height of the LED 230 (the length of the light guide plate 240 in the thickness direction).

  Accordingly, in the region R sandwiched between the divided conductive film portions 451 to 453 on one side surface 242 of the light guide plate 240 and facing the notch portion 320, the front and back surfaces of the light guide plate 240 and the electrode portions 454 to 457 and the LED 230. The part between is exposed on the notch side. Therefore, the reflected light of the LED 230 by the notch 320 can enter the light guide plate 240 from these exposed regions, and the light use efficiency of the LED in the light guide plate 240 can be improved. Thereby, the brightness | luminance efficiency and brightness | luminance uniformity in a light-guide plate can be improved.

(Modification 2)
FIG. 6 is a diagram for explaining a second modification of the surface light emitting device according to the second embodiment.

  In the surface light emitting device 500 shown in FIG. 6, an LED 230 and a conductive film portion 550 having a light shielding property and a conductive property to serve as an LED wiring are provided on one side surface 242 of the light guide plate 240 of the light guide plate unit 560. Yes.

  The conductive film portion 550 is attached to one side surface of the light guide plate 240 in a portion adjacent to the LED 230 in the longitudinal direction, and corresponds to the thickness of the light guide plate 240 (the length between the front and back surfaces) and substantially the same width as the thickness. Divided conductive film portions 551 to 553, and surface electrode portions 554 to 556 that are attached to the edge of the surface of the light guide plate 240 and connect the divided conductive film portions 551 to 553 and the side ends of the LEDs 230. ing.

  The divided conductive film portions 551 to 553 are arranged to face the inner peripheral surface 314 of the holder 310, and the end portions 551a, 552a, and 553a on the LED side of the divided conductive film portions 551 to 553 are respectively concave (here, arc-shaped). ) Of the notch 320 is disposed at a position facing both end edges 320a.

  The surface electrode portions 554 to 556 are connected to the divided conductive film portions 551 to 553 at the edge of the surface of the light guide plate 240, and the divided conductive film portion toward the LED 230 side adjacent to the divided conductive film portions 551 to 553. It extends from 551 to 553 and is electrically connected to the end portion of the LED 230 from the extended end portion (for example, the end portion 551b) via a hanging piece 557 that hangs down to a portion facing the notch portion 320.

  Thereby, in one side surface of the light guide plate 240, a region other than the region where the hanging piece 557 and the LED 230 are attached is located in the side region R1 sandwiched between the divided conductive film portions 551 to 553 and facing the notch 320. It is exposed to the notch 320 side. Therefore, the reflected light of the LED by the notch 320 can enter the light guide plate 240 from these exposed regions, and the light use efficiency of the LED in the light guide plate 240 can be improved.

(Modification 3)
FIG. 7 is a diagram for explaining a third modification of the surface light emitting device in the second embodiment.

  In the surface light emitting device 600 of FIG. 7, the LED 230 and a conductive film portion 650 having light shielding properties and conductivity to be a wiring of the LED 230 are provided on one side surface 242 of the light guide plate 240 of the light guide plate unit 660. .

  The conductive film portion 650 is attached to one side 242 of the light guide plate 240 at a portion adjacent to the LED 230 in the longitudinal direction, and corresponds to the thickness of the light guide plate 240 (the length between the front and back surfaces) and substantially the same as the thickness. Divided conductive film portions 651 to 653 having a width are provided. The divided conductive film portions 651 to 653 and the side end portion of the LED 230 are connected by a transparent electrode portion 655 which is a conductive member having translucency (property of transmitting light).

  Thereby, in one side 242 of the light guide plate 240, in a region R1 sandwiched between the divided conductive film portions 651 to 653 and facing the notch 320, a portion other than the portion where the LED 230 is attached is on the notch 320 side. Exposed. Therefore, the reflected light of the LED 230 from the notch 320 can enter the light guide plate 240 through these exposed regions, and the light use efficiency of the LED in the light guide plate 240 can be improved.

  In addition, in this Embodiment, when the light guide plate unit 360-660 was accommodated in the holder 310, the notch part 320 which accommodates LED230 demonstrated that the inner wall surface 322 was a curved surface, but it is not restricted to this. Any shape may be used as long as it reflects the light from the LED 230 toward the light guide plate 240 side.

  FIG. 8 is a plan view showing another example of the surface light emitting device in which only the shape of the notch portion is changed in the surface light emitting device of the second embodiment.

  In the surface light emitting device 700 shown in FIG. 8, the notches 720 of the holder 710 that accommodates the light guide plate unit 360 shown in FIGS. 3 and 4 are arranged on both sides of the LED 230 attached to the light guide plate 240 and face each other. The both side wall parts 723 and 724 are gradually spaced toward the light guide plate 240 side.

  As a result, light leaking from the LED to the notch portion side is introduced into the light guide plate 240 through the end surface portion exposed between the portion where the LED 230 is attached and the front and back surfaces of the light guide plate 240 on the side surface of the light guide plate 240. Incident light can improve the light use efficiency in the light guide plate 240. Therefore, the brightness of the light emitted from the surface of the light guide plate 240 by driving the LED, specifically, the light irradiating the liquid crystal panel side can be increased.

  The embodiment of the present invention has been described above.

  The surface light-emitting device according to the present invention is not limited to the above embodiments, and can be implemented with various modifications.

  In the second embodiment and the first to third modifications, the conductive film portion may be formed on the side surface of the light guide plate 240 by plating, applying a conductive paint, or printing, as in the first embodiment. Then, the film may be formed by sticking, vapor deposition or adhesion of a conductive film material.

  Note that the configuration of the holder in the surface light emitting device of the second embodiment may be applied to the holder of the first embodiment. That is, in the surface light emitting device, the holder is formed with a notch for housing the LED attached to the light guide plate 240. According to this, the same effect as the effect described in the second embodiment can be obtained. Of course, the configuration described in each modification of the second embodiment may be applied to the light guide plate unit.

  In the second embodiment, the inner peripheral surface of the notch formed in the holder is a curved surface. However, the present invention is not limited to this, and light from the LED accommodated in the notch can be efficiently transmitted to the light guide plate 240 side. As long as it reflects, it may be formed in any way. For example, a plurality of inclined surfaces extending in the opening direction of the holder and having different angles are formed on the inner peripheral surface of the notched portion formed in a concave shape, and light incident on these inclined surfaces is transmitted to the opening of the notched portion. You may make it reflect uniformly in a direction.

  The surface light emitting device according to the present invention can be mounted on an electronic device such as a communication terminal including a mobile phone together with a liquid crystal panel, thereby providing an electronic device having the same effect as the above. it can.

  The surface light-emitting device according to the present invention has the effect of increasing the light utilization efficiency with a simple configuration without positioning the light-emitting element with respect to the light guide plate, and is a surface light-emitting device used in an electronic device equipped with a liquid crystal panel. Useful as a device.

The figure which uses for description of the surface emitting device which concerns on Embodiment 1 of this invention. Schematic diagram for explaining the main structure of the light guide plate unit The top view of the surface emitting device for demonstrating the surface emitting device which concerns on Embodiment 2 of this invention. The figure which shows the light-guide plate unit which is the principal part of the same surface light-emitting device. The figure which uses for description of the modification 1 of the surface emitting device in Embodiment 2 The figure which uses for description of the modification 2 of the surface emitting device in Embodiment 2 The figure which uses for description of the modification 3 of the surface emitting device in Embodiment 2. The top view which shows another example of the surface emitting device which changed only the shape of the notch part in the surface emitting device of Embodiment 2. FIG. A diagram for explaining a conventional surface light-emitting device

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Electronic device 110 Liquid crystal panel 200, 300 Surface light-emitting device 210, 310 Holder 230 LED (light emitting element)
240 Light guide plate 250, 350, 450, 550, 650 Conductive film part 310, 710 Holder 312 Frame body 314 Inner peripheral surface 320 Notch part 322 Inner wall surface 554, 555, 556 Surface electrode part 655 Transparent electrode part

Claims (4)

A light guide plate;
A light emitting element provided on an outer periphery of the light guide plate;
A conductive film portion provided on a surface where the light emitting element is disposed, forming a wiring of the light emitting element and having a light shielding property;
A holder including a frame body that houses the light guide plate provided with the light emitting element and the conductive film portion;
The frame is formed with a notch for accommodating the light emitting element at a position corresponding to the position of the light emitting element attached to the light guide plate on the inner peripheral surface corresponding to the outer shape of the light guide plate.
The inner wall surface of the notch reflects incident light to the light guide plate,
The conductive film portion and the light emitting element are electrically connected to a portion of the outer peripheral surface of the light guide plate facing the notch, and the length of the light guide plate in the thickness direction is shorter than the conductive film portion. A surface light-emitting device comprising an electrode portion . A light guide plate;
A light emitting element provided on an outer periphery of the light guide plate;
A conductive film portion provided on a surface where the light emitting element is disposed, forming a wiring of the light emitting element and having a light shielding property;
A holder including a frame body that houses the light guide plate provided with the light emitting element and the conductive film portion;
The frame is formed with a notch for accommodating the light emitting element at a position corresponding to the position of the light emitting element attached to the light guide plate on the inner peripheral surface corresponding to the outer shape of the light guide plate.
The inner wall surface of the notch reflects incident light to the light guide plate,
In the outer peripheral surface of the light guide plate, a transparent electrode portion that is electrically connected to the conductive film portion and the light emitting element and has translucency is disposed at a portion facing the notch portion. Surface emitting device. A light guide plate;
A light emitting element provided on an outer periphery of the light guide plate;
A conductive film portion provided on a surface where the light emitting element is disposed, forming a wiring of the light emitting element and having a light shielding property;
A holder including a frame body that houses the light guide plate provided with the light emitting element and the conductive film portion;
The frame is formed with a notch for accommodating the light emitting element at a position corresponding to the position of the light emitting element attached to the light guide plate on the inner peripheral surface corresponding to the outer shape of the light guide plate.
The inner wall surface of the notch reflects incident light to the light guide plate,
On the outer peripheral surface of the light guide plate, electrode portions that electrically connect the conductive film portion and the light emitting element are disposed on the front and back surfaces of the light guide plate adjacent to the portion facing the notch portion. A surface light emitting device characterized by the above. A surface light-emitting device according to any one of claims 1 to 3,
An electronic apparatus comprising: a liquid crystal panel irradiated with light by the surface light emitting device.

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