JP4260547B2 - Flat lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plane light on two main and sub liquid crystal display screens with one back light by emitting bright homogeneous light from the both faces of the front face part and the rear face part of a light guide plate. <P>SOLUTION: A liquid crystal display device 1 has the light source 11, a surface illumination device, and two faces of liquid crystal display parts. The surface illumination device has an incidence part 10 to guide light from the light source 11, the front face part 8, and the rear face part 9 nearly perpendicularly crossing with the incidence part 10, and emits the light against both of the two faces of the light guide plate 7, by means of the light guide plate 7 to guide the light from the incidence part 10 and to totally reflect light existing inside into the mutually opposed face direction by a light deflection element 71 installed at the surface part 8 and the rear face part 9, and by means of a prism sheet 12 whose vertex angle turns to the light guide plate 7 so that the light outgoing from the light guide plate 7 will be deflected and emitted nearly perpendicularly. The light outgoing from both of the two faces of this light guide plate 7 is guided by two faces of liquid crystal panels or a liquid crystal cell, and displays characters and graphics from the two faces of the liquid crystal panels or the liquid crystal cell. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention provides a flat illumination device capable of emitting light from both the front and back surfaces of a light guide plate using a prism sheet or a diffusion sheet.In placeIt is related.
[0002]
[Prior art]
  Conventionally, when a liquid crystal display device displays in both the front surface direction and the back surface direction, for example, in a mobile product such as a mobile phone, when performing a liquid crystal display of a main screen and a liquid crystal display of a sub screen on the back side of a case, etc. It was the structure which was able to observe from the front and back using two liquid crystal display devices incorporating the.
[0003]
  In addition, a conventional backlight is used for the liquid crystal display on the main screen, and a transmissive liquid crystal such as a clear and bright TFT liquid crystal is used. On the sub-screen, a reflector is provided on the back surface of the backlight to provide a reflective liquid crystal. There was a thing of the composition which made it possible to observe from two sides of the front and back.
[0004]
[Problems to be solved by the invention]
  As described above, when displaying on the liquid crystal display device in both the front surface direction and the back surface direction in the related art, for example, in a mobile product such as a mobile phone, when performing the liquid crystal display of the main screen and the liquid crystal display of the sub screen on the back side of the case, etc. In the configuration in which two liquid crystal display devices incorporating a flat illumination device are used so that observation can be performed from the front and back surfaces, two sets of backlights are required, and a light guide plate that occupies a large proportion of the backlight configuration. Two sets of light sources are required as well as two sets.
[0005]
  In addition, a light guide plate used as a liquid crystal display device of a mobile product (for example, a mobile phone) becomes a big factor in weight and thickness, and there is a problem in lightening and downsizing (thickness) of the mobile product. .
[0006]
  In addition, since two sets of light sources are required, power consumption increases, battery life is shortened, and if the amount of batteries is increased to secure power, the size, weight, and economics can be reduced. There are challenges.
[0007]
  In addition, when a liquid crystal display device is provided on both the front and back surfaces, a conventional backlight is used for the liquid crystal display on the main screen, a transparent liquid crystal such as a bright and bright TFT liquid crystal is used, and a back screen is used for the sub screen. An object having a structure in which a reflector or the like is provided on the back surface of the light and the reflection type liquid crystal is used so that the light can be observed from the front and back surfaces can be sufficiently satisfied with respect to light weight and downsizing. However, since a reflective liquid crystal is used for the sub-screen, there are problems that the luminance is low and the color is not clear in the case of a color image.
[0008]
  The present invention has been made to solve the above-described problems. A light source and a light deflecting element are provided on the front surface portion and the back surface portion of the light guide plate. Use the light emitted on both sides of the back surface part, or use the light totally reflected in the opposite surface direction and emitted on one side and the refracted (leakage) light from the surface provided with the light deflection element, Furthermore, from the surface where the light deflection element is provided after being refracted by the light deflection elementBreak the critical angle to the outsideFrom the light guide plate using a light guide plate that utilizes the emitted light, and a pair of prism sheets having a prism sheet having an apex angle with respect to the light guide plate and a prism surface having an apex angle opposite to the light guide plate and intersecting each other The emitted light is deflected and emitted substantially perpendicular to the surface of the light guide plate, and bright uniform light is emitted from both the front and back sides of the light guide plate by a diffusion sheet that diffuses the light. For example, plane light can be supplied to the screens of the main and sub two liquid crystal display devices with one backlight, and the light guide plate and the prism sheet or the diffusion sheet can be used to reduce the size of the sub screen. It is an object of the present invention to provide a flat illumination device that emits light from both directions (both sides) that can provide a plane emission light having a size suitable for a purpose by providing a reflector having an opening partly in between.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, a flat illumination device according to claim 1 of the present invention includes a light source, an incident portion that guides light from the light source, a front surface portion and a back surface portion that intersect the incident portion at a substantially right angle, and is incident. Guide the light from the inside to the front and back partsrandomlyProvidedConvex or concave dot shapeOptical deflection elementThe inclined surface in the direction of the incident part and the direction opposite to the incident partDepending on the inclined surfaceTotally reflectedIn the direction of the faces facing each otherProceed with deflecting lightFrom both front and backBreak the critical angle to the outsideA light guide plate that emits light, and a prism sheet that has a prism surface whose apex angle is directed to the light guide plate, and that deflects light emitted from the light guide plate substantially vertically with respect to both sides of the light guide plate. Features.
[0010]
  The flat illumination device according to claim 1 includes a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle. On the front and backrandomlyProvidedConvex or concave dot shapeOptical deflection elementThe inclined surface in the direction of the incident part and the direction opposite to the incident partDepending on the inclined surfaceTotally reflectedIn the direction of the faces facing each otherProceed with deflecting lightFrom both front and backBreak the critical angle to the outsideSince it has a light guide plate that emits, and a prism sheet that has a prism surface with an apex angle directed to the light guide plate and deflects light emitted from the light guide plate substantially perpendicularly to both surfaces of the light guide plate, By using a light source or light beam that is not related to directivity, the light beam is refracted by the prism sheet regardless of the light exit angle from the front or back surface of the light guide plate, and light is emitted from both sides of the light guide plate at once. Can do.
[0011]
  Further, the flat illumination device according to claim 2 has a light source, an incident portion for guiding light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle, and is led from the incident portion and exists inside. Light on the front or back sideRandomly convex or concave dotsAn optical deflection element is provided.The inclined surface in the direction of the incident part and the direction opposite to the incident partTotal reflection in the direction of the opposing surface by the inclined surfaceThe light is deflected and advanced, and the critical angle is broken from both sides of the front and back surfaces and emitted to the outside.And light deflection elementInclined surface in the direction of the incident part or in the direction opposite to the incident partThe light guide plate that is refracted by the light and emits in both directions of the front surface portion and the back surface portion, the prism sheet having a prism surface with the apex angle facing the surface, and the diffusion sheet that diffuses the refracted light from the surface provided with the light deflection element The light emitted by the total reflection by the prism sheet and the diffusion sheet is emitted to both sides of the light guide plate.
[0012]
  The flat illumination device according to claim 2 includes a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at substantially right angles, and is guided from the incident portion and is present inside. On the front or backRandomly convex or concave dotsAn optical deflection element is provided.The inclined surface in the direction of the incident part and the direction opposite to the incident partTotal reflection in the direction of the opposing surface by the inclined surfaceThe light is deflected and advanced, and the critical angle is broken from both sides of the front and back surfaces and emitted to the outside.And light deflection elementInclined surface in the direction of the incident part or in the direction opposite to the incident partThe light guide plate that is refracted by the light and emits in both directions of the front surface portion and the back surface portion, the prism sheet having a prism surface with the apex angle facing the surface, and the diffusion sheet that diffuses the refracted light from the surface provided with the light deflection element Since the light emitted by total reflection by the prism sheet and the diffusion sheet is emitted to both sides of the light guide plate, only the surface on which the light deflection element is provided using a directional light source or light beam. Thus, outgoing light can be obtained from both sides of the light guide plate at one time.
[0013]
  Furthermore, the flat illumination device according to claim 3 has a light source, an incident portion that guides light from the light source, and a front surface portion and a rear surface portion that intersect with the incident portion at substantially right angles, and is led from the incident portion and exists inside. Refracted by the inclined surface in the direction of the incident portion or the inclined surface in the direction opposite to the incident portion of the convex or concave dot-shaped light deflecting element provided randomly on the front surface portion and the rear surface portion. From both sidesBreak the critical angle to the outsideA light guide plate that emits light and a prism surface whose apex angle is directed to the light guide plate, and the light emitted from both the front surface portion and the back surface portion of the light guide plate is deflected substantially perpendicularly to both surfaces of the light guide plate and emitted. And a prism sheet.
[0014]
  The flat illumination device according to claim 3 has a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle, and is guided from the incident portion and is present inside. Refracted by the inclined surface in the direction of the incident portion of the convex or concave dot-shaped light deflecting element provided randomly on the front surface portion and the back surface portion, or both of the front surface portion and the back surface portion FromBreak the critical angle to the outsideA light guide plate that emits light and a prism surface whose apex angle is directed to the light guide plate, and the light emitted from both the front surface portion and the back surface portion of the light guide plate is deflected substantially perpendicularly to both surfaces of the light guide plate and emitted. A light beam with a large output angle from the front and back surfaces of a light guide plate provided with a light deflector using a non-directional light source or light beam. Outgoing light can be obtained from both sides of the light plate.
[0015]
  The flat illumination device according to claim 4 has a light source, an incident portion for guiding light from the light source, and a front surface portion and a back surface portion intersecting at substantially right angles with the incident portion, and is led from the incident portion and exists inside. Light on the front and back sidesrandomlyProvidedConvex or concave dot shapeOptical deflection elementThe inclined surface in the direction of the incident part and the direction opposite to the incident partDepending on the inclined surfaceTotally reflectedIn the direction of the faces facing each otherProceed with deflecting lightFrom both front and backBreak the critical angle to the outsideA pair of light guide plates that emit light and prism surfaces that face each other on opposite sides of the light guide plate and intersect each other, and light emitted from the light guide plates is deflected substantially perpendicularly to both surfaces of the light guide plate and emitted. And a prism sheet.
[0016]
  The flat illumination device according to claim 4 includes a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle, and is guided from the incident portion and is present inside. On the front and backrandomlyProvidedConvex or concave dot shapeOptical deflection elementThe inclined surface in the direction of the incident part and the direction opposite to the incident partDepending on the inclined surfaceTotally reflectedIn the direction of the faces facing each otherProceed with deflecting lightFrom both front and backBreak the critical angle to the outsideA pair of light guide plates that emit light and prism surfaces that face each other on opposite sides of the light guide plate and intersect each other, and light emitted from the light guide plates is deflected substantially perpendicularly to both surfaces of the light guide plate and emitted. Since the prism sheet is provided, both sides of the light guide plate at once are refracted by the prism sheet using a light source and light rays that are not related to directivity, regardless of the exit angle from the front and back surfaces of the light guide plate. The outgoing light can be obtained from both.
[0017]
  Furthermore, the flat illumination device according to claim 5 has a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle, and is led from the incident portion and exists inside. Light on the front or back sideRandomly convex or concave dotsAn optical deflection element is provided.The inclined surface in the direction of the incident part and the direction opposite to the incident partTotal reflection in the direction of the opposing surface by the inclined surfaceThe light is deflected and advanced, and the critical angle is broken from both sides of the front and back surfaces and emitted to the outside.And light deflection elementInclined surface in the direction of the incident part or in the direction opposite to the incident partThe light guide plate that is refracted by the light and emits in both directions of the front surface portion and the back surface portion, the diffusion sheet that diffuses the refracted light from the surface on which the light deflection element is provided, and the apex angle faces the opposite side of the surface and intersects each other A pair of prism sheets having a prism surface, and light emitted by total reflection by the diffusion sheet and the pair of prism sheets is emitted to both sides of the light guide plate.
[0018]
  The flat illumination device according to claim 5 includes a light source, an incident portion that guides light from the light source, and a front surface portion and a rear surface portion that intersect with the incident portion at substantially right angles, and is guided from the incident portion and is present inside. On the front or backRandomly convex or concave dotsAn optical deflection element is provided.The inclined surface in the direction of the incident part and the direction opposite to the incident partTotal reflection in the direction of the opposing surface by the inclined surfaceThe light is deflected and advanced, and the critical angle is broken from both sides of the front and back surfaces and emitted to the outside.And light deflection elementInclined surface in the direction of the incident part or in the direction opposite to the incident partThe light guide plate that is refracted by the light and emits in both directions of the front surface portion and the back surface portion, the diffusion sheet that diffuses the refracted light from the surface on which the light deflection element is provided, and the apex angle faces the opposite side of the surface and intersects each other A pair of prism sheets having a prism surface, and light emitted by total reflection by both the diffusion sheet and the pair of prism sheets is emitted to both sides of the light guide plate. The emitted light can be obtained from both surfaces of the light guide plate at a time using only the surface on which the light deflection element is provided.
[0019]
  The flat illumination device according to claim 6 has a light source, an incident portion for guiding light from the light source, and a front surface portion and a back surface portion intersecting at substantially right angles with the incident portion, and is led from the incident portion and is present inside. Refracted by the inclined surface in the direction of the incident portion or the inclined surface in the direction opposite to the incident portion of the convex or concave dot-shaped light deflecting element provided randomly on the front surface portion and the rear surface portion. From both sidesBreak the critical angle to the outsideA light guide plate that emits light and a prism surface that has an apex angle opposite to the light guide plate and intersects with each other, and light emitted from both the front surface portion and the back surface portion of the light guide plate is approximately on both surfaces of the light guide plate. And a pair of prism sheets that are vertically deflected and emitted.
[0020]
  The flat illumination device according to claim 6 has a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at substantially right angles, and is guided from the incident portion and is present inside. Refracted by the inclined surface in the direction of the incident portion of the convex or concave dot-shaped light deflecting element provided randomly on the front surface portion and the back surface portion, or both of the front surface portion and the back surface portion FromBreak the critical angle to the outsideA light guide plate that emits light and a prism surface that has an apex angle opposite to the light guide plate and intersects with each other, and light emitted from both the front surface portion and the back surface portion of the light guide plate is approximately on both surfaces of the light guide plate. Since a pair of prism sheets that are deflected and emitted vertically are used, a light beam with a large emission angle from the front and back surfaces of the light guide plate provided with the light deflection element using a non-directional light source or light beam is prismed. By refraction by the sheet, outgoing light can be obtained from both sides of the light guide plate at a time.
[0023]
  Claims7The flat illuminating device according to the present invention is characterized in that a reflector having an opening part is provided below the back surface of the light guide plate.
[0024]
  Claim7Since the flat illumination device according to the aspect of the invention has a reflector partially having an opening under the back surface of the light guide plate, the light emitted from the back surface other than the light emitted from the opening is returned to the light guide plate again. Can do.
[0025]
  And claims8The flat illuminating device according to the present invention is characterized in that a colored sheet partially having an opening is provided below the back surface of the light guide plate.
[0026]
  Claim8The flat illumination device according to the present invention is provided with a colored sheet having an opening partly under the back surface part of the light guide plate, and therefore, when white is used as the color of the reflector, the contrast between the reflector and the opening is reduced. Can do.
[0027]
  Claims9The flat illumination device according to the present invention has a light deflection elementConsists of convex and concave shapes such as dot-shaped elliptical arc, cone, and polygonal pyramidIt is characterized by that.
[0028]
  Claim9The flat illumination device according to the present invention has a light deflection elementConsists of convex and concave shapes such as dot-shaped elliptical arc, cone, and polygonal pyramidTherefore, a light beam having a large emission angle or a light beam having a small emission angle can be emitted from the front surface portion or the back surface portion of the light guide plate.
[0029]
  Furthermore, the planar illumination device according to claim 10 is a prism sheet.Is a prism surface having a substantially triangular cross-section formed in a linear or concentric arc shape on the surface.It is characterized by having.
[0030]
  The flat illumination device according to claim 10 is a prism sheet.Is a prism surface having a substantially triangular cross-section formed in a linear or concentric arc shape on the surface.Therefore, a light beam having a large emission angle emitted from the light guide plate is emitted in a direction substantially perpendicular to the front surface portion and / or the back surface portion by the prism sheet. Thereby, the emitted light can be obtained from the entire front surface with respect to the observation side.
0031]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
  In the present invention, the light source and the light guide plate are provided with light deflecting elements on the front surface portion and the back surface portion, and are totally reflected so as to advance and emit in the surface directions where the front surface portion and the back surface portion face each other. An optical deflecting element is provided on the surface, or an optical deflecting element is provided to cause the total reflection on either the front surface portion or the back surface portion to advance and emit in the direction of the surfaces facing each other. A light guide plate that refracts light on the surface side and emits part of the light from the light source, and further provides a light deflecting element on the front and back surfaces to refract light from the light source and emits the light from the front and back surfaces. When the emission angle from the light guide plate is large (output along the surface of the light guide plate) among the light emitted from these light guide plates, the light is refracted by one inclined surface and taken in, and all the other inclined surfaces The apex angle with respect to the light guide plate is reflected so as to be emitted substantially perpendicular to the light guide plate. Planar outgoing light in both directions of the front and back sides by a prism sheet, a prism sheet having a prism surface whose apex angle is opposite to the other side of the light guide plate, and a diffusion sheet that diffuses highly directional outgoing light Two-way (double-sided) emission flat illumination devicePlaceIt is to provide.
0032]
  FIG. 1A shows a planar illumination device according to the present invention in which a planar illumination device that emits light from both sides is disposed between two liquid crystal panels or liquid crystal cells.An example (including a liquid crystal display device) is shown.It is a schematic perspective view, a front perspective view of a mobile phone, FIG. 2 (b) is a rear perspective view of the mobile phone, FIG. 2 (a) is a front perspective view of a foldable mobile phone, and FIG. 2 (b) is a foldable mobile phone. The rear perspective view of the telephone, FIG. 3 relates to the present inventionFlat lightingFIG. 4 is a schematic side sectional view of the apparatus, showing an example in which a main liquid crystal display device and a sub liquid crystal display device are provided on both sides of one flat illumination device, and FIG. 4 is an example of the flat illumination device according to the present invention. FIG. 5 to FIG. 7 are partially enlarged side sectional views showing other examples of the flat illumination device according to the present invention.8FIG. 9 is a schematic perspective view showing still another example of the flat illumination device according to the present invention.Is a bookFIG. 6 is a schematic side sectional view showing another embodiment of a liquid crystal display device including a flat illumination device according to the invention.10(A), (b) is a figure for demonstrating the effect of the opening part of a coloring sheet, a figure11(A), (b) is a figure for demonstrating the effect of the presence or absence of a coloring sheet, a figure12FIG. 3 is a schematic side sectional view showing still another embodiment of a liquid crystal display device including a flat illumination device according to the present invention.13Is a figure12Liquid crystal display deviceWhen usingIt is a disassembled perspective view of the flat illuminating device in.
0033]
  FIGS. 1A and 1B and FIGS. 2A and 2B show a mobile phone as an example of a mobile product including a liquid crystal display device using a flat illumination device according to the present invention.
0034]
  The mobile phone 2 stores various components in a front surface side case 3 and a back surface side case 4. The front case 3 is provided with a main screen 5 for displaying various push buttons such as numbers and various information as a telephone. The main screen 5 includes a main liquid crystal panel, a liquid crystal cell, and the like (not shown), and a backlight light guide plate is provided below the main screen 5.
0035]
  Further, the back case 4 is provided with a sub-screen 6 for displaying various information such as time and the telephone number of the other party at the time of incoming call. The sub screen 6 has a sub liquid crystal panel, a liquid crystal cell, etc. (not shown), and a light guide plate of a backlight is provided below the sub screen 6.
0036]
  The light guide plate used for the backlights of the main and sub liquid crystal panels and liquid crystal cells is composed of a single-sided or single-sided light guide plate.
0037]
  Hereinafter, the flat lighting device according to the present invention employed in mobile products such as the mobile phone 2 will be described.Device 1 (including liquid crystal display)The configuration of will be described.
0038]
  As shown in FIG.Flat lightingThe apparatus 1 has a light source 11 for supplying light to the light guide plate 7 and a convex or concave shape for emitting light existing inside the light guide plate 7 to both surfaces of the front surface portion 8 and the rear surface portion 9 by the light source 11. A light guide plate 7 provided with light deflecting elements 71 made of prisms, dots or the like on each of the front surface portion 8 and the back surface portion 9, and the front surface portion 8 and the back surface portion 9 above the front surface portion 8 and the back surface portion 9 of the light guide plate 7. A prism sheet 12 for emitting light emitted from the substrate substantially vertically, a diffusion sheet 13 for diffusing the emitted light to make it uniform, and an emission area of the emitted light from the front surface portion 8 and the back surface portion 9 Consists of a reflector 14 partially having an opening 14a for control.The
0039]
  The light guide plate 7 is formed in a substantially rectangular shape using transparent acrylic resin (PMMA), polycarbonate (PC), or the like. The light guide plate 7 has at least one side surface portion as the incident portion 10 and has the light deflection element 71 on the front surface portion 8 and / or the back surface portion 9 (the front surface portion 8 and the back surface portion 9 in the example of FIG. 3). .
0040]
  Further, the arrangement, distribution, and shape of the light deflection element 71 provided on the light guide plate 7 are determined according to the purpose, as shown in FIGS.
0041]
  Here, for example, when the material of the light guide plate 7 is polycarbonate (PC) resin, the refractive index n of the polycarbonate resin is 1.59. Therefore, the light beam that enters the light guide plate 7 from the incident portion 10 through the air layer is 0 ≦ | α | ≦ sin.^-1From the equation (1 / n) (where n is an air layer and refractive index n = 1), the light is present in the light guide plate 7 as light within a range of a substantially refraction angle α = ± 38.9713 °.
0042]
  Further, the light incident on the light guide plate 7 within the range of the refraction angle α = ± 38.997 ° is sin γ = (1 / n at the boundary surface between the light guide plate 7 and the air layer (refractive index n = 1). ) Can be used to express the critical angle. For example, since the refractive index of polycarbonate resin, which is a resin material used for a general light guide plate 7, is about n = 1.59, the critical angle γ is about γ = 38.97 °. In the case of a light guide plate using an acrylic resin (PMMA) material, the refractive index n of the acrylic resin is about n = 1.49 and the refraction angle α is about α = 42.38 °. The angle γ is also about γ = 42.38 °.
0043]
  Liquid crystal display device of this exampleIn placePlanar illuminator used1As shown in FIG. 4, convex or concave light deflecting elements 71 are formed on the front surface portion 8 and the rear surface portion 9 of the light guide plate 7, and both surfaces of the light guide plate 7 (the front surface portion 8 side and the rear surface portion) are formed. The prism sheet 12 can be provided on the (9 side). In this case, among the light traveling from the incident portion 10 into the light guide plate 7, the light beams L 1, L 2, L 3, and L 4 travel in the direction of the front surface portion 8 and the back surface portion 9. Total reflection is performed by the inclined surface of the portion 10 in the opposite direction. The totally reflected light beams L12, L22, L32, and L42 travel in the direction of the opposing surfaces, break the critical angle, and emit light beams L13, L23, L33, and L43 from the light guide plate 7. That is, light rays are emitted from opposite sides opposite to the surface on which the light deflection element 71 is provided.
0044]
  At this time, depending on the shape of the light deflection element 71 provided on the light guide plate 7 (the angle at which the light is totally reflected), in the case of the light rays L33 and L43 having a large emission angle, the apex angle is directed toward the light guide plate 7. By the prism sheet 12 provided on the upper portion (surface portion 8) of the light guide plate 7, the light beams L33 and L43 having a large emission angle are slightly refracted from one inclined surface of the prism sheet 12, and proceed into the prism sheet 12 as light beams L34 and L44. . The light beams L34 and L44 are further totally reflected at the other inclined surface of the prism sheet 12, and are deflected substantially perpendicular to the surface of the light guide plate 7 to emit light beams L35 and L45.
0045]
  Further, as shown in FIGS. 5 and 6, a light deflection element 71 is formed on either the front surface portion 8 or the back surface portion 9 of the light guide plate 7, and the surface side on which the light deflection element 71 is formed (FIG. 5 or FIG. 5). In the example of FIG. 6, the diffusion sheet 13 is provided on the back surface portion 9 side of the light guide plate 7 and the surface side where the light deflection element 71 is not formed (in the example of FIGS. 5 and 6, the surface portion 8 side of the light guide plate 7). ) May be provided with a prism sheet 12. In this case, of the light beams L01 and LL1 that have reached the light deflecting element 71 depending on the shape of the light deflecting element 71 and the incident angle of the light beam, a part of the light beams L02 undergo total reflection, and in the facing surface direction (surface portion 8). The light beam L03 is emitted to the outside by breaking the critical angle of the light guide plate 7. Further, a part of the light beam LL2 is refracted and transmitted by the light deflecting element 71 and emits the light beam LL3 to the outside.
0046]
  At this time, depending on the shape of the light deflection element 71 provided on the light guide plate 7 (the angle at which the light is totally reflected), the light guide plate 7 has an apex angle directed toward the light guide plate 7 in the case of the light ray L03 having a large emission angle. The light beam L03 having a large emission angle is slightly refracted from one inclined surface of the prism sheet 12 by the prism sheet 12 provided on the upper portion (surface portion 8) of the light beam 7, and proceeds into the prism sheet 12 as the light beam L04. The light beam L04 is further totally reflected by another inclined surface of the prism sheet 12, and is deflected substantially perpendicular to the surface of the light guide plate 7 to emit the light beam L05.
0047]
  Further, the light beam refracted by the light deflecting element 71, transmitted, and emitted to the outside exits the light cone LLd which is diffused and spread by the diffusion sheet 13 which diffuses the light.
  5 shows a case where the light deflection element 71 has a concave shape, and FIG. 6 shows a case where the light deflection element 71 has a convex shape.
0048]
  Further, as shown in FIG. 7, convex or concave light deflection elements 71 are formed on the front surface portion 8 and the back surface portion 9 of the light guide plate 7, and both surfaces of the light guide plate 7 (the front surface portion 8 side and the back surface portion 9 are formed). The prism sheet 12 can be provided on the side). In this case, the light beam LB reaching the light deflecting element 71 is refracted by the light deflecting element 71, and the light beam LB1 is emitted from the front surface portion 8 and the back surface portion 9 to the outside.
[0049]
  At this time, the outgoing light beam LB1 isBreak the critical angle to the outsideExit. Therefore, the light beam LB1 emitted from the light guide plate 7 is slightly refracted from one inclined surface of the prism sheet 12 by the prism sheet 12 whose apex angle is directed to the light guide plate 7 by the prism sheet 12 provided on the upper surface portion 8 and the back surface portion 9. Then, the light beam LB2 travels into the prism sheet 12. The light beam LB2 further undergoes total reflection at the other inclined surface of the prism sheet 12, and is deflected substantially perpendicular to the surface of the light guide plate 7 to emit the light beam LB3.
0050]
  Here, the light deflection element 71 has been described with a convex shape or a concave shape having an arc shape, but other shapes such as an elliptical arc, a cone, a cylinder, a polygonal shape, etc.ConeIn addition, the light deflecting element 71 has a shape such as a polygonal column, which is randomly provided on the front surface portion 8 or the back surface portion 9 of the light guide plate 7, or a pillow-shaped convex portion or concave portion having an arc shape or a polygonal cross section.NonYou may make it provide continuously.
0051]
  Further, the light deflection element 71 has an elliptical arc, a cone, a cylinder, a polygonConeEven in the case of a convex shape such as a polygonal column or a concave shape, the same operations and effects as those of the above-described configuration can be obtained, and the description will be omitted.
0052]
  In addition, the figure8As shown, the light guide plate 7 is formed by concentrically positioning a pillow-shaped convex part or concave part of the light deflection element 71 having an arc-shaped or polygonal cross section on one or both sides of the front surface part 8 or the back surface part 9.NonIt is good also as a structure provided continuously.
0053]
  In the example of FIG. 8, in order to provide the light source 11 at the corner with respect to the light guide plate 7, the light deflection element 71 is provided at a concentric position centering on the light source 11 so as to face the light source 11. A storage portion 70 for storing the light source 11 in the light guide plate 7 is integrally formed at the corner of the light guide plate 7. And the light source 11 is inserted in this accommodating part 70, and the mechanical stability is aimed at.
0054]
  Further, in FIG. 8, the prism sheets 12 provided on both sides of the light guide plate 7 have an apex angle 72 having an arc distribution corresponding to the light deflection element 71 in the same manner as the light deflection element 71 provided on the light guide plate 7. The apex angle 72 faces the front surface portion 8 and the back surface portion 9 of the light guide plate 7.
0055]
  further,lightThe deflection element 71 is concentric with the light source 11 as a center with respect to the front surface portion 8 and the back surface portion 9 of the light guide plate 7.NonYou may make it provide continuously.
0056]
  Furthermore, a prism sheet 12 is provided on the upper surface portion 8 and the rear surface portion 9, and the light beam LC1 emitted from the light guide plate 7 is slightly refracted from one inclined surface of the prism sheet 12 by the prism sheet 12 having an apex angle toward the light guide plate 7. Thus, the light beam LC2 advances into the prism sheet 12. This light beam LC2 is further totally reflected by another inclined surface of the prism sheet 12, and is deflected substantially perpendicularly to the surface of the light guide plate 7 to emit a light beam LC3.
0057]
  GuidanceOptical deflection element 7 of optical plate 71 is, As mentioned above, arc, elliptical arc, cone, cylinder, polygonConeAlternatively, convex or concave dots such as polygonal columns may be continuously provided at concentric positions.
[0058]
  The prism sheet 12 is formed from a transparent resin such as acrylic resin (PMMA) or polycarbonate (PC). The prism sheet 12 isOn that planeCross-sectional shape is approximately triangularofA prism surface is formed, and light emitted from the light guide plate 7 is deflected substantially vertically with respect to the light guide plate 7 to be totally reflected.
  The prism sheet 12 is on the sheet surface.Straight lineOr as shown in FIG.Concentric arcCan be provided.
0059]
  The diffusion sheet 13 is formed from a transparent resin such as acrylic resin (PMMA) or polycarbonate (PC). The diffusion sheet 13 has a minute uneven surface and serves to spread light like a wide light cone.
0060]
  For example, as shown in FIG. 3, the reflector 14 is provided with an opening 14 a corresponding to the size of the small liquid crystal panel 6 or the liquid crystal cell 6 used for the sub screen 6 or the like, and a planar light source necessary for the sub screen 6.OfferTo pay.
0061]
  In addition, the light that has leaked from the light guide plate 7 to the light guide plate 7, the prism sheet 12, the diffusion sheet 13, and the like is returned to the light guide plate 7 again by a metal, a glossy material of metal, a white material, or the like. Use light.
0062]
  The light source 11 is composed of a CCFL (cold cathode tube) or the like, and has a linear line shape, an L shape (L), a U shape, or the like, and direct light enters the light guide plate 7 from the incident portion 10 of the light guide plate 7. To do. Further, if necessary, using a reflector (not shown) or the like, light other than the light incident from the incident portion 10 enters the light guide plate 7 through the space between the light source 11 and the reflector while being reflected by the reflector.
0063]
  The light source 11 is not limited to a linear CCFL, and may be an array having semiconductor light emitting elements arranged as a linear light source.
0064]
  Further, the light source 11 is composed of, for example, an LED or a laser made of a semiconductor light emitting element, and is converted into white light by wavelength conversion using monochromatic light, white of RGB (red, green, blue) or a fluorescent material. It can also be used.
0065]
  Further, when the light guide plate 7 has a plurality of incident portions 10 at the corner where the two side surface portions intersect, white light is emitted from the entire light guide plate 7 using light sources 11 of different emission colors at the respective incident portions. It may be emitted.
0066]
  Although not shown here, a reflector made of a metal, a glossy material of metal, or a white material may be provided on the outer periphery of the light source 11.
0067]
  By the way, in this example, it is illustrated as a liquid crystal display device including a flat illumination device.9The thing of the structure shown to can also be employ | adopted. Figure9In FIG.Flat lightingConstituent elements that are the same as those of the apparatus 1 are denoted by the same reference numerals, and the specific configurations and functions thereof are also the same, and the description thereof is omitted.
0068]
  Figure9Shown inFlat lightingThe apparatus 1 includes a light source 11, a light guide plate 7, a prism sheet 12, a diffusion sheet 13, a polarization reflection sheet 21, a coloring sheet 22, and a case 23.For convenience of explanation,A liquid crystal panel 5 or a liquid crystal cell 5 used as a main screen and a liquid crystal panel 6 or a liquid crystal cell 6 used as a sub screen are roughly configured.
0069]
  The light source 11 supplies light to the incident portion 10 of the light guide plate 7. The light guide plate 7 has at least one side surface as an incident portion 10 and has a light deflection element 71 formed of a convex or concave prism or dot on the front surface portion 8 and / or the back surface portion 9 (see FIG.9In the example, the front surface portion 8 and the back surface portion 9).
0070]
  The prism sheet 12 is provided above the front surface portion 8 and below the back surface portion 9 of the light guide plate 7. The prism sheet 12 has a prism surface whose apex angle is directed to the light guide plate 7 and emits light beams emitted from the front surface portion 8 and the back surface portion 9 of the light guide plate 7 substantially vertically.
0071]
  The diffusion sheet 13 is provided above one prism sheet 12 and below the other prism sheet 12. The diffusion sheet 13 emits a light cone having a spread by diffusing the light emitted from the prism sheet 12 substantially vertically.
0072]
  The colored sheet 22 is,flatIt arrange | positions in the lowest layer of case 23 in which each component of a surface illuminating device is accommodated. The coloring sheet 22 has an opening 22 a corresponding to the opening 23 a of the case 23. These openings 22a and 23a are formed in accordance with the size of the liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen..
0073]
  By the way, when the opening 22a of the colored sheet 22 has the same size as the opening 23a of the case 23, FIG.10As shown in (b), there arises a problem that the return light of the scattered light generated at the end face of the opening 23a of the case 23 to the flat illumination device cannot be blocked.
0074]
  Therefore, in this example, when the case 23 is light (white),10As shown to (a), the opening part 22a of the coloring sheet 22 is set a little smaller than the size of the opening part 23a of the case 23. FIG. Thereby, the return light to the plane illumination device side of the scattered light generated at the end face of the opening 23a of the case 23 can be shielded.
0075]
  According to the configuration using the colored sheet 22, the contrast between the case 23 in which each component of the flat illumination device is accommodated and the opening 23a can be reduced.
0076]
  To explain further, conventional double-sided backlights are11As shown in (b), the liquid crystal panel 6 or the liquid crystal cell 6 (dark color and absorption unique to the polarizing plate) used as a sub-screen is directly viewed in the opening 23a of the case 23. For this reason, the difference in contrast between the case 23 and the liquid crystal panel 6 or the liquid crystal cell 6 used as the sub-screen is different from the side of the liquid crystal panel 5 or the liquid crystal cell 5 used as the main screen due to the difference in the degree of reflection. I can confirm.
0077]
  So, in this example,11As shown in (a), a film-like colored sheet 22 colored in a dark color system (black, dark gray, etc.) on the lowermost layer on the liquid crystal panel 6 or liquid crystal cell 6 side used as a sub-screen, that is, the inner surface of the case 23. With a configurationIfThe above-mentioned contrast is reduced. Thereby, the visual recognition of the opening 23a of the case 23 facing the liquid crystal panel 6 or the liquid crystal cell 6 used as the sub screen from the liquid crystal panel 5 or the liquid crystal cell 5 side used as the main screen can be suppressed.
0078]
  In addition, in the structure which does not use the coloring sheet | seat 22 mentioned above, it is preferable to color case 23 itself. According to this configuration, the contrast control by the colored sheet 22 is also performed by the case 23, and an increase in the number of components can be reduced.
0079]
  By the way, FIG. 3 and FIG.9In the configuration shown in FIG. 3, the apex angle 72 of the prism surface of the prism sheet 12 provided on the front surface portion 8 and / or the back surface portion 9 of the light guide plate 7 faces the light guide plate 7 side.12Or figure13As shown, the apex angle 72 of the prism surface of the prism sheet 12 may be directed to the opposite side of the light guide plate 7.
0080]
  Figure12IsFlat lightingDressSetSchematic side sectional view showing another embodiment, figure13Is a figure12It is a disassembled perspective view of the flat illuminating device in. 3 and figure9The same number is attached | subjected to the same component, and since the concrete structure and effect | action are the same, description is abbreviate | omitted.
0081]
  Figure12Shown inFlat lightingThe apparatus 1 includes a light source 11, a light guide plate 7, a diffusion sheet 13, a prism sheet 12, a polarization reflection sheet 21, a coloring sheet 22, and a case 23.For convenience of explanation,A liquid crystal panel 5 or a liquid crystal cell 5 used as a main screen and a liquid crystal panel 6 or a liquid crystal cell 6 used as a sub screen are roughly configured.
0082]
  The light source 11 supplies light to the incident portion 10 of the light guide plate 7. The light guide plate 7 has at least one side surface portion as an incident portion 10, and has a light deflection element 71 formed of convex or concave prisms or dots on the front surface portion 8 or the back surface portion 9 (see FIG.12In the example of FIG.
0083]
  The diffusion sheet 13 is provided above the front surface portion 8 of the light guide plate 7 and below the back surface portion 9. The diffusion sheet 13 emits a light cone having a spread by diffusing light emitted from the front surface portion 8 and the back surface portion 9 of the light guide plate 7.
0084]
  The prism sheet 12 is composed of a pair of prism sheets 12A and 12B whose prism surfaces intersect each other (90 °). The prism sheet 12 is provided above one diffusion sheet 13 and below the other diffusion sheet 13. The pair of prism sheets 12 </ b> A and 12 </ b> B has a prism surface whose apex angle is directed to the opposite side of the light guide plate 7, and emits light beams emitted from the diffusion sheet 13 substantially vertically.
0085]
  The polarizing reflection sheet 21 is provided below the prism sheet 12 disposed on the back surface 9 side of the light guide plate 7. The polarization reflection sheet 21 is installed so that the polarization axis is the same as the polarization axis of the liquid crystal panel 6 or the liquid crystal cell 6 used as a sub-screen, and has the above-described functions and effects.
0086]
  The colored sheet 2210And figure11It has the above-mentioned functions and operational effects explained using The colored sheet 22 is located below the polarizing reflection sheet 21 and is disposed in the lowermost layer of the case 23 in which each component of the flat illumination device is accommodated. The coloring sheet 22 has an opening 22 a corresponding to the opening 23 a of the case 23..
0087]
  The opening 22a of the coloring sheet 22 is set slightly smaller than the size of the opening 23a of the case 23 when the case 23 is light color (white). Thereby, the return light to the plane illumination device side of the scattered light generated at the end face of the opening 23a of the case 23 can be shielded.
0088]
  And configured as aboveFlat lightingWhen the apparatus 1 is employed in a mobile phone having a camera function, for example, it functions as a finder and can confirm still images such as photographs. Similarly, in the case of a moving image, it can serve as a finder view (monitor) of the video camera and confirm a moving image.
0089]
  By the way, figure9Or figure12Shown inFlat lightingIn the device 1, instead of the case 23,For exampleIt is good also as the reflector 14 which has the opening part 14a corresponding to the magnitude | size of the small liquid crystal panel 6 used for a subscreen, or the liquid crystal cell 6. FIG.
0090]
  Also figure12ofFlat lightingIn the apparatus 1, a light deflection element 71 is provided on the front surface portion 8 or the back surface portion 9 of the light guide plate 7, and light incident on the light guide plate 7 from the light source 11 is totally reflected by the light deflection element 71 in the facing surface direction. The light is deflected by the light deflection element 71 and emitted from the front surface portion 8 and the back surface portion 9 of the light guide plate 7. But figure12As the minimum required configuration, the light source 11, the light guide plate 7, the prism sheet 12, the case 23 (or the reflector))soYes, the diffusion sheet 13, the polarizing reflection sheet 21, and the coloring sheet 22 are added as necessary.
0091]
  For example, in the configuration in which the light deflection element 71 is provided on the front surface portion 8 and the back surface portion 9 of the light guide plate 7 and the light totally reflected by the light deflection element 71 is emitted from both the front surface portion 8 and the back surface portion 9 of the light guide plate 7, Figure12It is possible to omit the diffusion sheet 13, the polarizing reflection sheet 21, and the coloring sheet 22.
0092]
  The same applies to a configuration in which a light deflection element 71 is provided on the front surface portion 8 or the back surface portion 9 of the light guide plate 7 and light refracted by the light deflection element 71 is emitted from both the front surface portion 8 and the back surface portion 9 of the light guide plate 7. It is.
[0093]
【The invention's effect】
  As described above, the flat illumination device according to claim 1 has a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle, and is led from the incident portion. The light existing inside the front and back partsrandomlyProvidedConvex or concave dot shapeOptical deflection elementThe inclined surface in the direction of the incident part and the direction opposite to the incident partDepending on the inclined surfaceTotally reflectedIn the direction of the faces facing each otherProceed with deflecting lightFrom both front and backBreak the critical angle to the outsideSince it has a light guide plate that emits, and a prism sheet that has a prism surface with an apex angle directed to the light guide plate and deflects light emitted from the light guide plate substantially perpendicularly to both surfaces of the light guide plate, Light emitted from both surfaces of the light guide plate can be obtained at once by refraction of the light beam by a prism sheet, regardless of the output angle from the front and back surfaces of the light guide plate, using a light source and light beams that are not related to directivity. . Thereby, it is possible to reduce the thickness of the flat illumination of a liquid crystal display device or the like composed of main and sub two screens and to obtain two flat illumination with one light source, which is excellent in small size, thin economy.
[0094]
  Further, the flat illumination device according to claim 2 has a light source, an incident portion for guiding light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle, and is led from the incident portion and exists inside. Light on the front or back sideRandomly convex or concave dotsAn optical deflection element is provided.The inclined surface in the direction of the incident part and the direction opposite to the incident partTotal reflection in the direction of the opposing surface by the inclined surfaceThe light is deflected and advanced, and the critical angle is broken from both sides of the front and back surfaces and emitted to the outside.And light deflection elementInclined surface in the direction of the incident part or in the direction opposite to the incident partThe light guide plate that is refracted by the light and emits in both directions of the front surface portion and the back surface portion, the prism sheet having a prism surface with the apex angle facing the surface, and the diffusion sheet that diffuses the refracted light from the surface provided with the light deflection element Since the light emitted by total reflection by the prism sheet and the diffusion sheet is emitted to both sides of the light guide plate, only the surface on which the light deflection element is provided using a directional light source or light beam. Thus, outgoing light can be obtained from both sides of the light guide plate at one time. Thereby, it is possible to reduce the thickness of the flat illumination of a liquid crystal display device or the like composed of main and sub two screens and to obtain two flat illumination with one light source, which is excellent in small size, thin economy.
[0095]
  Furthermore, the flat illumination device according to claim 3 has a light source, an incident portion that guides light from the light source, and a front surface portion and a rear surface portion that intersect with the incident portion at substantially right angles, and is led from the incident portion and exists inside. Refracted by the inclined surface in the direction of the incident portion or the inclined surface in the direction opposite to the incident portion of the convex or concave dot-shaped light deflecting element provided randomly on the front surface portion and the rear surface portion. From both sidesBreak the critical angle to the outsideA light guide plate that emits light and a prism surface whose apex angle is directed to the light guide plate, and the light emitted from both the front surface portion and the back surface portion of the light guide plate is deflected substantially perpendicularly to both surfaces of the light guide plate and emitted. A light beam with a large output angle from the front and back surfaces of a light guide plate provided with a light deflector using a non-directional light source or light beam. Outgoing light can be obtained from both sides of the light plate. Thereby, it is possible to reduce the thickness of the flat illumination of a liquid crystal display device or the like composed of main and sub two screens and to obtain two flat illumination with one light source, which is excellent in small size, thin economy.
[0096]
  The flat illumination device according to claim 4 has a light source, an incident portion for guiding light from the light source, and a front surface portion and a back surface portion intersecting at substantially right angles with the incident portion, and is led from the incident portion and exists inside. Light on the front and back sidesrandomlyProvidedConvex or concave dot shapeOptical deflection elementThe inclined surface in the direction of the incident part and the direction opposite to the incident partDepending on the inclined surfaceTotally reflectedIn the direction of the faces facing each otherProceed with deflecting lightFrom both front and backBreak the critical angle to the outsideA pair of light guide plates that emit light and prism surfaces that face each other on opposite sides of the light guide plate and intersect each other, and light emitted from the light guide plates is deflected substantially perpendicularly to both surfaces of the light guide plate and emitted. Since the prism sheet is provided, both sides of the light guide plate at once are refracted by the prism sheet using a light source and light rays that are not related to directivity, regardless of the exit angle from the front and back surfaces of the light guide plate. The outgoing light can be obtained from both. Thereby, it is possible to reduce the thickness of the flat illumination of a liquid crystal display device or the like composed of main and sub two screens and to obtain two flat illumination with one light source, which is excellent in small size, thin economy.
[0097]
  Furthermore, the flat illumination device according to claim 5 has a light source, an incident portion that guides light from the light source, and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle, and is led from the incident portion and exists inside. Light on the front or back sideRandomly convex or concave dotsAn optical deflection element is provided.The inclined surface in the direction of the incident part and the direction opposite to the incident partTotal reflection in the direction of the opposing surface by the inclined surfaceThe light is deflected and advanced, and the critical angle is broken from both sides of the front and back surfaces and emitted to the outside.And light deflection elementInclined surface in the direction of the incident part or in the direction opposite to the incident partThe light guide plate that is refracted by the light and emits in both directions of the front surface portion and the back surface portion, the diffusion sheet that diffuses the refracted light from the surface on which the light deflection element is provided, and the apex angle faces the opposite side of the surface and intersects each other A pair of prism sheets having a prism surface, and light emitted by total reflection by both the diffusion sheet and the pair of prism sheets is emitted to both sides of the light guide plate. The emitted light can be obtained from both surfaces of the light guide plate at a time using only the surface on which the light deflection element is provided. Thereby, it is possible to reduce the thickness of the flat illumination of a liquid crystal display device or the like composed of main and sub two screens and to obtain two flat illumination with one light source, which is excellent in small size, thin economy.
[0098]
  The flat illumination device according to claim 6 has a light source, an incident portion for guiding light from the light source, and a front surface portion and a back surface portion intersecting at substantially right angles with the incident portion, and is led from the incident portion and is present inside. Refracted by the inclined surface in the direction of the incident portion or the inclined surface in the direction opposite to the incident portion of the convex or concave dot-shaped light deflecting element provided randomly on the front surface portion and the rear surface portion. From both sidesBreak the critical angle to the outsideA light guide plate that emits light and a prism surface that has an apex angle opposite to the light guide plate and intersects with each other, and light emitted from both the front surface portion and the back surface portion of the light guide plate is approximately on both surfaces of the light guide plate. Since a pair of prism sheets that are deflected and emitted vertically are used, a light beam with a large emission angle from the front and back surfaces of the light guide plate provided with the light deflection element using a non-directional light source or light beam is prismed. By refraction by the sheet, outgoing light can be obtained from both sides of the light guide plate at a time. Thereby, it is possible to reduce the thickness of the flat illumination of a liquid crystal display device or the like composed of main and sub two screens and to obtain two flat illumination with one light source, which is excellent in small size, thin economy.
[0100]
  Claims7In the flat illumination device according to the aspect of the invention, since the reflector having the opening partly is provided below the back surface part of the light guide plate, the light emitted from the back surface part other than the light emitted from the opening part is returned to the light guide plate again. be able to. As a result, light can be used without waste and brighter outgoing light can be obtained.
[0101]
  And claims8The flat illumination device according to the present invention is provided with a colored sheet having an opening partly under the back surface part of the light guide plate, and therefore, when white is used as the color of the reflector, the contrast between the reflector and the opening is reduced. Can do. As a result, when the liquid crystal panel or liquid crystal cell of the sub screen is arranged facing the opening of the reflector, it is possible to suppress the visibility of the sub screen from the liquid crystal panel or liquid crystal cell side of the main screen through the opening of the reflector. it can.
[0102]
  And claims9The flat illumination device according toConsists of convex and concave shapes such as dot-shaped elliptical arc, cone, and polygonal pyramidTherefore, a light beam having a large emission angle or a light beam having a small emission angle can be emitted from the front surface portion or the back surface portion of the light guide plate. And it can design freely, without being restrict | limited with respect to the number of light sources, the position to provide, and the magnitude | size of a plane illuminating device.
[0103]
  The planar illumination device according to claim 10 is a prism sheet.Is a prism surface having a substantially triangular cross-section formed in a linear or concentric arc shape on the surface.Therefore, a light beam having a large emission angle emitted from the light guide plate is emitted in a direction substantially perpendicular to the front surface portion and / or the back surface portion by the prism sheet. Thereby, the emitted light can be obtained from the entire front surface with respect to the observation side, and a bright and easy-to-see image or character can be recognized.
[Brief description of the drawings]
1A and 1B are planer illumination devices that emit light from both sides between two liquid crystal panels or liquid crystal cells.An example (including a liquid crystal display device) is shown.It is a schematic perspective view, a front perspective view and a rear perspective view of a mobile phone
FIGS. 2A and 2B are related to the present invention in which a flat illumination device emitting light from both sides is arranged between two liquid crystal panels or liquid crystal cells.Flat lightingapparatus(Including liquid crystal display devices)FIG. 2 is a front perspective view and a rear perspective view of a foldable mobile phone.
FIG. 3 relates to the present invention.Flat lightingFIG. 4 is a schematic side sectional view of the apparatus, showing an example in which a main liquid crystal display device and a sub liquid crystal display device are provided on both sides of one flat illumination device
FIG. 4 is a partially enlarged side sectional view showing an example of a flat illumination device according to the present invention.
FIG. 5 is a partially enlarged side sectional view showing another example of the flat illumination device according to the present invention.
FIG. 6 is a partially enlarged side sectional view showing another example of the flat illumination device according to the present invention.
FIG. 7 is an exploded perspective view showing another example of the flat illumination device according to the present invention.
FIG. 8 is a schematic perspective view showing still another example of the flat illumination device according to the present invention.
[Figure9A schematic side sectional view showing another embodiment of a liquid crystal display device including a flat illumination device according to the present invention.
[Figure10(A) Partial sectional view when a colored sheet having an opening smaller than the opening of the reflector (case) is provided on the inner surface side of the reflector (case)
  (B) Partial sectional view when a colored sheet having an opening having the same size as the opening of the reflector (case) is provided on the inner surface side of the reflector (case)
[Figure11(A) Partial sectional view when a colored sheet is present on the inner surface of the reflector (case)
  (B) Partial sectional view when there is no colored sheet on the inner surface side of the reflector (case)
[Figure12A schematic side sectional view showing still another embodiment of a liquid crystal display device including a flat illumination device according to the present invention.
[Figure13] Figure12Liquid crystal display deviceWhen usingExploded perspective view of a flat illumination device
[Explanation of symbols]
  1 ...Flat lightingDevice: 2 ... mobile phone, 3 ... front case, 4 ... back side case, 5 ... main screen (main liquid crystal panel, main liquid crystal cell), 6 ... sub screen (sub liquid crystal panel, sub liquid crystal cell) , 7 ... Light guide plate, 8 ... Front part, 9 ... Back part, 10 ... Incident part, 11 ... Light source, 12 ... Prism sheet, 13 ... Diffuser sheet, 14 ... Reflector, 14a ... Opening part, 21 ... Polarized reflection sheet 22 ... Colored sheet, 22a ... Opening, 23 ... Case, 23a ... Opening, 70 ... Storage part, 71 ... Light deflection element, 72 ... Vertical angle of arc distribution prism sheet, α ... Refraction angle, n ... Refractive index , Γ ... critical angle, S1, S3 ... convex ridge line, S2, S4 ... valley (concave ridge) line, LLd ... light cone, L01, L02, L03, L04, L05, L1, L2, L3, L4, L12, L13, L22, L23, L32, L33, L34, L35, L 42, L43, L44, L45, LB, LB1, LB2, LB3, LL1, LL2, LL3...

Claims (10)

  A light source; an incident portion that guides light from the light source; and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle. The light is deflected in the direction opposite to each other by total reflection from the inclined surface in the direction of the incident part of the convex or concave dot-shaped light deflecting element provided randomly at the part or the inclined surface in the direction opposite to the incident part. A light guide plate that breaks the critical angle from both the front surface portion and the back surface portion and emits the light to the outside, and a prism surface whose apex angle faces the light guide plate, and guides the light emitted from the light guide plate. A planar illumination device comprising: a prism sheet that deflects and emits substantially perpendicularly to both sides of the optical plate.   A light source; an incident portion that guides light from the light source; and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle. The light that is guided from the incident portion and is present inside the front surface portion or the back surface A convex or concave dot-shaped light deflecting element is randomly provided on the part, and is totally reflected in the surface direction facing the inclined surface in the direction of the incident part of the light deflecting element or in the direction opposite to the incident part. Deflection of light advances, breaks the critical angle from both directions of the front surface portion and the back surface portion, emits the light to the outside, and refracts by the inclined surface in the direction of the incident portion of the light deflection element or the inclined surface in the direction opposite to the incident portion. Then, a light guide plate that emits light in both directions of the front surface portion and the back surface portion, a prism sheet having a prism surface whose apex angle is directed to the surface, and refracted light from the surface on which the light deflection element is provided are diffused. A diffusion sheet, and the prism sheet and the front Flat illumination device, characterized in that the exit for both surfaces of the light guide plate the light emitted by the total reflection by the diffusion sheet. A light source; an incident portion that guides light from the light source; and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle. Refracted by the inclined surface in the direction of the incident portion of the convex or concave dot-shaped light deflection element provided randomly at the portion or the inclined surface in the direction opposite to the incident portion, and from both the front surface portion and the back surface portion A light guide plate that breaks a critical angle and emits the light to the outside, and a prism surface having an apex angle toward the light guide plate, and emits light emitted from both the front surface portion and the back surface portion of the light guide plate. And a prism sheet for deflecting and emitting substantially perpendicularly to both of the flat illumination device.   A light source; an incident portion that guides light from the light source; and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle. The light is deflected in the direction opposite to each other by total reflection from the inclined surface in the direction of the incident part of the convex or concave dot-shaped light deflecting element provided randomly at the part or the inclined surface in the direction opposite to the incident part. The light guide plate that breaks the critical angle from both the front surface portion and the back surface portion and emits the light to the outside, and the prism surface whose apex angle faces the other side of the light guide plate and intersects each other, from the light guide plate A flat illumination device, comprising: a pair of prism sheets that deflect and emit emitted light substantially perpendicularly to both sides of the light guide plate.   A light source; an incident portion that guides light from the light source; and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle. The light that is guided from the incident portion and is present inside the front surface portion or the back surface A convex or concave dot-shaped light deflecting element is randomly provided on the part, and is totally reflected in the surface direction facing the inclined surface in the direction of the incident part of the light deflecting element or in the direction opposite to the incident part. Deflection of light advances, breaks the critical angle from both directions of the front surface portion and the back surface portion, emits the light to the outside, and refracts by the inclined surface in the direction of the incident portion of the light deflection element or the inclined surface in the direction opposite to the incident portion. And a light guide plate that emits light in both directions of the front surface portion and the back surface portion, a diffusion sheet that diffuses refracted light from the surface on which the light deflection element is provided, and an apex angle that faces the opposite side of the surface. A pair of prism sheets having intersecting prism surfaces And, planar lighting device, characterized in that for emitting the light emitted by the total reflection between the diffusion sheet by said pair of prism sheets to both surfaces of the light guide plate. A light source; an incident portion that guides light from the light source; and a front surface portion and a back surface portion that intersect with the incident portion at a substantially right angle. Refracted by the inclined surface in the direction of the incident portion of the convex or concave dot-shaped light deflection element provided randomly at the portion or the inclined surface in the direction opposite to the incident portion, and from both the front surface portion and the back surface portion A light guide plate that breaks a critical angle and exits to the outside, and a prism surface that faces the opposite side of the light guide plate and has an apex angle that intersects each other, and is emitted from both the front surface portion and the back surface portion of the light guide plate And a pair of prism sheets that deflect and emit substantially perpendicularly to both sides of the light guide plate.   The said light guide plate provided the reflector which has an opening part partially under the said back surface part, The planar illuminating device in any one of Claims 1-6 characterized by the above-mentioned.   The said light guide plate provided the coloring sheet | seat which has an opening part partially under the said back surface part, The planar illuminating device in any one of Claims 1-6 characterized by the above-mentioned.   The planar illumination device according to any one of claims 1 to 6, wherein the light deflection element has a convex or concave shape such as a dot-like elliptical arc, a cone, or a polygonal pyramid. The planar illumination device according to any one of claims 1 to 6, wherein the prism sheet has a prism surface having a substantially triangular cross section formed on the surface thereof in a linear or concentric arc shape .

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