WO2013154124A1 - Illumination device and display device provided with same - Google Patents

Illumination device and display device provided with same Download PDF

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Publication number
WO2013154124A1
WO2013154124A1 PCT/JP2013/060784 JP2013060784W WO2013154124A1 WO 2013154124 A1 WO2013154124 A1 WO 2013154124A1 JP 2013060784 W JP2013060784 W JP 2013060784W WO 2013154124 A1 WO2013154124 A1 WO 2013154124A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
incident
light source
light guide
refractive index
Prior art date
Application number
PCT/JP2013/060784
Other languages
French (fr)
Japanese (ja)
Inventor
一郎 梅川
弘文 大澤
壮史 石田
龍三 結城
和哉 八田
秀悟 八木
Original Assignee
シャープ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by シャープ株式会社 filed Critical シャープ株式会社
Publication of WO2013154124A1 publication Critical patent/WO2013154124A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0016—Grooves, prisms, gratings, scattering particles or rough surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0055—Reflecting element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
    • G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources

Definitions

  • the present invention relates to a lighting device having a light guide plate and a display device including the same.
  • Patent Document 1 A conventional display device is disclosed in Patent Document 1.
  • This display device includes an illumination device and a liquid crystal display panel. An image is displayed by irradiating the liquid crystal display panel with illumination light emitted from the illumination device.
  • the lighting device has a light source including a fluorescent lamp, a light guide plate, a diffusion sheet, a reflection sheet, and a lamp reflector.
  • the light guide plate is made of a resin molded product having a substantially rectangular shape in plan view with the front surface and the back surface formed flat.
  • the light guide plate has an incident surface facing the light source on the side surface, and an exit surface for illumination light is formed on the front surface. Light emitted from the light source enters from the incident surface of the light guide plate and is guided, and illumination light is emitted from the output surface of the light guide plate.
  • the diffusion sheet is arranged to face the exit surface of the light guide plate and diffuses the light emitted from the exit surface.
  • the reflection sheet is disposed to face the back surface of the light guide plate, reflects light emitted from the back surface of the light guide plate, and returns the light to the light guide plate.
  • the lamp reflector is arranged so as to surround the light source, and reflects the light emitted from the light source toward the incident surface of the light guide plate.
  • One end of the lamp reflector is adhered to the exit surface near the entrance surface of the light guide plate by a double-sided adhesive tape containing a black pigment, and the other end is disposed on the back side of the reflection sheet.
  • One end of the reflection sheet is bonded to the back surface near the incident surface of the light guide plate by a double-sided adhesive tape containing a black pigment.
  • the illumination device of the conventional display device a part of the light emitted from the light source is directly incident on the light source side side end surface of the double-sided adhesive tape without being incident on the incident surface, and is absorbed by the double-sided adhesive tape. The For this reason, a part of the light emitted from the light source cannot be guided in the light guide plate, and the light guided in the light guide plate is reduced. Therefore, there has been a problem that the luminance of the entire exit surface of the illumination device is reduced.
  • An object of the present invention is to provide an illuminating device capable of improving the luminance of the entire emission surface and a display device including the illuminating device.
  • the present invention has a light source and an incident surface facing the light source at a side end surface, and guides light incident from the incident surface to emit illumination light from an exit surface arranged on the front surface.
  • the light guide plate includes a first prism that includes the incident surface and the light exit surface and includes a first inclined surface in the optical axis direction of the light source.
  • a low refractive index layer having a refractive index smaller than that of the light guide portion adjacent to the back surface of the light guide portion, and a surface opposite to the exit surface with respect to the low refractive index layer.
  • a second prism including two inclined surfaces arranged in parallel in the optical axis direction, arranged in contact with the light source side side end surface of the low refractive index layer and the light collecting portion, and A first light reflecting portion for reflecting the light emitted from the light source and guiding it to the incident surface is provided. It is set to.
  • the light emitted from the light source enters the light guide portion of the light guide plate from the incident surface.
  • the light incident on the light guide unit is reflected and guided by the front exit surface and the back surface.
  • the incident angles on the exit surface and the back surface gradually increase due to reflection on the first inclined surface.
  • Light incident on the back surface of the light guide unit at an incident angle smaller than the critical angle enters the low refractive index layer.
  • light reflected by the first inclined surface and having an incident angle smaller than the critical angle is incident on the low refractive index layer, and light larger than the critical angle is reflected again by the first inclined surface and the incident angle is reduced.
  • the light When the angle is smaller than the critical angle, the light enters the low refractive index layer. Thereby, the incident angle of the light incident on the low refractive index layer is reduced to a predetermined range according to the inclination angle of the first inclined surface.
  • Light incident on the low refractive index layer and incident on the second inclined surface at an incident angle larger than the critical angle is reflected in the direction of the exit surface, passes through the light guide, and exits from the exit surface.
  • light incident on the second inclined surface with an incident angle smaller than the critical angle is refracted by the second inclined surface when exiting from the condensing unit, and is incident on the condensing unit again.
  • the present invention preferably includes a housing that houses the light source and the light guide plate, and the first light reflecting portion is formed by containing a white pigment or a silver pigment in the housing.
  • the first light reflecting portion is formed by containing a white pigment or a silver pigment in the housing.
  • the first light reflecting portion is formed of an adhesive tape-like member containing a white pigment or a silver pigment. According to this configuration, a part of the light emitted from the light source is reflected by the adhesive tape-like member and enters the light guide unit from the incident surface.
  • a second light reflecting portion that is arranged on the opposite side of the first light reflecting portion with respect to the light source and reflects the emitted light of the light source to guide the incident surface. It is more preferable to provide further. According to this configuration, part of the light emitted from the light source is reflected by the second light reflecting portion and enters the light guide portion from the incident surface.
  • the display device of the present invention is characterized by including the illumination device having the above-described configuration and a display panel disposed to face the emission surface of the light guide plate.
  • the light guide plate has a light guide portion having an entrance surface and an exit surface, a low refractive index layer adjacent to the back surface of the light guide portion, and a surface opposite to the exit surface with respect to the low refractive index layer.
  • a first light reflecting portion that is disposed in contact with the side surface on the light source side of the low refractive index layer and the light collecting portion and that reflects the emitted light of the light source and guides it to the incident surface. Provided. Thereby, the light emitted from the light source enters the light guide plate from the incident surface without directly entering the low refractive index layer and the condensing part.
  • the light emitted from the light source is directly incident on the low refractive index layer and the light converging part and then reflected by the light converging part and emitted from the light emitting surface near the incident surface.
  • the amount of light guided in the direction away from the incident surface in the light guide plate can be increased, and the luminance of the entire emission surface can be improved.
  • Side surface sectional drawing which shows the display apparatus of 1st Embodiment of this invention.
  • Sectional drawing which expands the entrance plane vicinity of the light-guide plate of the illuminating device of the display apparatus of 1st Embodiment of this invention, and shows a cross section perpendicular
  • the display device 1 includes a display panel 10 and a lighting device 20.
  • the display panel 10 includes a liquid crystal display panel, and includes an active matrix substrate 11 including a switching element such as a thin film transistor (TFT: Thin Film Transistor), and a counter substrate 12 facing the active matrix substrate 11.
  • TFT Thin Film Transistor
  • Liquid crystal 14 is injected between the active matrix substrate 11 and the counter substrate 12.
  • a polarizing film 13 is disposed on each of the light receiving surface side of the active matrix substrate 11 and the light emitting surface side of the counter substrate 12.
  • the liquid crystal display panel 10 has a display area A and a non-display area NA.
  • the display area A is an area for displaying an image
  • the non-display area NA is an area for not displaying an image.
  • the non-display area NA is formed around the display area A.
  • the lighting device 20 includes a housing 25, a light source 21, and a light guide plate 30.
  • the housing 25 is formed in a frame shape with an open center, and houses the light source 21 and the light guide plate 30.
  • the opening on the lower surface of the housing 25 is covered with a sheet-like reflecting member 24.
  • the housing 25 is formed of a light absorbing material such as a resin molded product containing a black pigment.
  • the housing 25 may be formed by applying a light absorbing material such as a black paint on a base material such as resin or metal.
  • the light source 21 is composed of an LED (Light Emitting Diode), and a plurality of light sources 21 are arranged in one direction (X direction).
  • the light guide plate 30 is formed in a rectangular shape in plan view with a transparent resin or the like.
  • the side surface of the light guide plate 30 faces the light source 21 to form an incident surface 30a on which light emitted from the light source 21 enters, and the front surface facing the display panel 10 forms an output surface 30b that emits illumination light.
  • the longitudinal direction of the incident surface 30a is the X direction
  • the optical axis direction of the light source 21 orthogonal to the X direction is the Y direction
  • the emission direction of the light guide plate 30 orthogonal to the X direction and the Y direction is the Z direction.
  • the reflection member 24 reflects the light emitted from the back surface of the light guide plate 30 and returns it to the light guide plate 30.
  • the light utilization efficiency can be improved by the reflecting member 24.
  • a sheet-shaped light shielding member 26 is disposed on the periphery of the light exit surface 30 b of the light guide plate 30.
  • the light shielding member 26 is formed in a frame shape having an opening at the center, and is disposed to face the non-display area NA.
  • the light shielding member 26 is made of, for example, polyester (PET: Polyester) and contains a black pigment.
  • An adhesive (not shown) is disposed on one side of the light shielding member 26, and the light shielding member 26 is adhered to the emission surface 30b by the adhesive.
  • the light guide plate 30 includes a light guide part 35, a low refractive index layer 36, and a light collecting part 37 stacked in the Z direction.
  • the light guide 35 is formed of a transparent resin such as acrylic or polycarbonate, and has an incident surface 30a and an output surface 30b, and guides light incident from the light source 21.
  • the refractive index n1 of the light guide 35 is preferably 1.42 or more, more preferably 1.59 to 1.65.
  • the refractive index n1 can be about 1.49.
  • the refractive index n1 can be about 1.59. If the light guide part 35 is formed of acrylic, the translucency can be further improved as compared with the case where it is formed of polycarbonate.
  • a plurality of prisms 32 (third prisms) extending in the Y direction are juxtaposed in the X direction on the emission surface 30 b of the light guide 35.
  • the prism 32 is recessed on the exit surface 30b and has a cross-sectional shape such as an arc, an elliptical arc, other curves, or a triangle.
  • the light emitted from the light source 21 and incident from the incident surface 30a is diffused and reflected by the prism 32 in the longitudinal direction (X direction) of the incident surface 30a.
  • the incident light can be made uniform by diffusing the light incident from the plurality of light sources 21 composed of LEDs that emit point light in the X direction.
  • the prism 32 may be omitted.
  • a plurality of prisms 33 (first prisms) arranged in the Y direction are provided between the adjacent prisms 32 on the light exit surface 30 b of the light guide plate 30.
  • a horizontal plane 34 parallel to the XY plane is provided between the prisms 33 adjacent in the Y direction.
  • the prism 33 may be formed continuously and the horizontal plane 34 may be omitted.
  • the prism 33 has a vertical surface 33a perpendicular to the XY plane and an inclined surface 33b (first inclined surface) inclined in the YZ plane.
  • the inclined surface 33b is inclined in a direction approaching the low refractive index layer 36 as it is away from the incident surface 30a, and has a predetermined inclination angle ⁇ with respect to a direction (Y direction) orthogonal to the incident surface 30a.
  • the inclination angle ⁇ is preferably an angle of 5 ° or less, more preferably an angle of 0.1 ° to 3 °.
  • the length of the inclined surface 33b in the Y direction is preferably 0.25 mm or less, and more preferably 0.01 mm to 0.10 mm.
  • the low refractive index layer 36 is adjacent to the back surface 35a of the light guide 35 and has a lower refractive index than the light guide 35.
  • the low refractive index layer 36 is formed of a resin containing hollow particles such as a fluorine-based acrylate or a nano-sized inorganic filler.
  • the refractive index n2 of the low refractive index layer 36 is preferably less than 1.42, more preferably 1.10 to 1.35. Further, it is preferable that a relationship of n1 / n2> 1.18 is established between the refractive index n1 of the light guide 35 and the refractive index n2 of the low refractive index layer 36.
  • the refractive index n2 can be about 1.35.
  • the refractive index n2 can be made 1.30 or less.
  • the condensing part 37 is adjacent to the low refractive index layer 36 and has the same or larger refractive index than the low refractive index layer 36. Therefore, the condensing part 37 may be formed of the same member as the low refractive index layer 36.
  • FIG. 5 shows a cross-sectional view perpendicular to the incident surface 30 a of the light collecting portion 37.
  • the prism 38 has a vertical surface 38a perpendicular to the XY plane and an inclined surface 38b (second inclined surface) inclined in the YZ plane.
  • the inclined surface 38b is inclined in a direction approaching the low refractive index layer 36 as the distance from the incident surface 30a increases, and has a predetermined inclination angle ⁇ with respect to the Z direction.
  • the length of the inclined surface 38b in the Y direction is about 0.1 mm or less, preferably about 0.01 mm to about 0.025 mm.
  • the inclination angle ⁇ is the apex angle of the prism 38, and is preferably 40 ° to 50 °.
  • the vertical surface 38a may be formed inclined with respect to the Y direction. At this time, the apex angle of the prism 38 may be set to 40 ° to 50 °.
  • the sheet-like reflecting member 60 (first light reflecting portion) is disposed so as to be in contact with the side surfaces 36a and 37a on the light source 21 side of the low refractive index layer 36 and the light collecting portion 37.
  • the reflecting member 60 reflects a part of the light emitted from the light source 21 (miscellaneous light) and guides it to the incident surface 30a.
  • the reflection member 60 is formed of an adhesive tape-like member such as polyester containing a white pigment or a silver pigment, and is attached to the front surface of the reflection member 24.
  • the thickness of the reflecting member 60 is set to be equal to or greater than the total thickness of the low refractive index layer 36 and the condensing part 37 (thickness in the Z direction).
  • the width (width in the X direction) is equal to or greater than the width (width in the X direction) of the low refractive index layer 36 and the light collecting portion 37
  • the side surfaces 36 a and 37 a of the low refractive index layer 36 and the light collecting portion 37 are reflected by the reflecting member 60. Can be completely covered. Thereby, it can prevent more reliably that the emitted light of the light source 21 injects into the low refractive index layer 36 and the condensing part 37 directly.
  • the light emitted from the light source 21 has the highest intensity in the front direction (Y direction) of the light source 21 and spreads in the X direction and the Z direction with respect to the front direction (Y direction).
  • Light emitted from the light source 21 is refracted when entering the incident surface 30 a of the light guide 35. If the refraction angle at this time is ⁇ 0 and the critical angle between the light guide 35 and the air is ⁇ 1, ⁇ 0 ⁇ 1.
  • the light incident from the incident surface 30a of the light guide part 35 is reflected and guided between the exit surface 30b and the back surface 35a.
  • Light traveling from the incident surface 30a toward the exit surface 30b is incident on the horizontal surface 34 or the inclined surface 33b.
  • the incident angle of light incident on the horizontal plane 34 is 90 ° ⁇ 1 or more.
  • the incident angle ⁇ 1 of the light Q1 incident on the inclined surface 33b is 90 ° ⁇ 1- ⁇ or more.
  • the light Q3 reflected by the back surface 35a is incident on the exit surface 30b.
  • the incident angle of the light incident on the horizontal plane 34 is ⁇ 2
  • the incident angle ⁇ 3 of the light incident on the inclined surface 33b is 90 ° ⁇ 1 ⁇ 3 ⁇ ⁇ or more.
  • light incident on the emission surface 30b at an incident angle smaller than the critical angle ⁇ 1 is emitted from the emission surface 30b, and light incident at an incident angle larger than the critical angle ⁇ 1 is totally reflected.
  • the light Q4 reflected by the inclined surface 33b enters the back surface 35a at an incident angle ⁇ 4.
  • the incident angle ⁇ 4 is 90 ° ⁇ 1 ⁇ 4 ⁇ ⁇ or more.
  • the light incident on the back surface 35a with an incident angle smaller than the critical angle ⁇ 2 enters the low refractive index layer 36, and the light incident on the back surface 35a with an incident angle larger than the critical angle ⁇ 2 is totally reflected.
  • the light that is guided through the light guide 35 is gradually reduced in the incident angle of the exit surface 30b and the back surface 35a due to the reflection of the inclined surface 33b.
  • the incident angle at the interface between the light guide 35 and the low refractive index layer 36 decreases by 2 ⁇ ⁇ , and enters the low refractive index layer 36 when it becomes smaller than the critical angle ⁇ 2. For this reason, the range of incident angles of light incident on the low refractive index layer 36 from the light guide 35 is ⁇ 2 to ⁇ 2-2 ⁇ ⁇ .
  • the light incident on the low refractive index layer 36 passes through the low refractive index layer 36 and enters the light collecting portion 37.
  • the refractive index n3 of the light condensing part 37 is the same as or larger than the refractive index n2 of the low refractive index layer 36, total reflection at the interface between the low refractive index layer 36 and the light converging part 37 does not occur.
  • the light incident on the condensing unit 37 enters the inclined surface 38b (see FIG. 5) of the prism 38.
  • Light incident on the inclined surface 38b at an incident angle larger than the critical angle ⁇ 3 between the light collecting portion 37 and air is totally reflected in the direction of the exit surface 30b.
  • the light incident on the inclined surface 38b at an incident angle smaller than the critical angle ⁇ 3 is refracted and emitted from the condensing unit 37, and is refracted and incident again from the vertical surface 38a to the condensing unit 37.
  • the light is refracted and the incident angle of the inclined surface 38b gradually increases, so that the light is totally reflected by the inclined surface 38b.
  • the light reflected by the inclined surface 38b is emitted from the emission surface 30b.
  • the directivity angle of the light emitted from the emission surface 30b can be narrowed down to the direction (Y direction) orthogonal to the ridgelines of the prisms 33 and 38. Therefore, it is not necessary to provide a prism sheet or the like on the emission surface 30b, and the number of parts and the number of manufacturing steps can be reduced. As a result, the manufacturing cost of the lighting device 20 can be reduced.
  • the light Q5 traveling from the incident surface 30a toward the back surface 35a of the light guide 35 is repeatedly reflected between the light exit surface 30b and the back surface 35a and enters the low refractive index layer 36. . Then, the light is reflected by the inclined surface 38b of the prism 38 and is emitted from the emission surface 30b.
  • the incident angle of the light guide portion 35 with respect to the light guiding low refractive index layer 36 is decreased by 2 ⁇ ⁇ , and sequentially enters the low refractive index layer 36 and is emitted from the emission surface 30b.
  • emitted from the end surface 30c (refer FIG. 4) facing the entrance plane 30a can be decreased.
  • the casing 25 can be thinned to narrow the frame of the lighting device 20, and the lighting device 20 and the display device 1 can be downsized.
  • FIG. 6 is a cross-sectional view in which the vicinity of the incident surface 30a of the light guide plate 30 is enlarged and perpendicular to the incident surface 30a. Since the reflecting member 60 is disposed in contact with the low refractive index layer 36 and the light collecting portion 37, a part of the light P1 emitted from the light source 21 enters the reflecting member 60 and is collected by the low refractive index layer 36 and the light collecting light. It does not enter the part 37 directly. The light P2 reflected by the reflecting member 60 enters the light guide 35 from the incident surface 30a. The light P3 incident on the light guide 35 is guided in a direction away from the incident surface 30a (Y direction) and then emitted from the exit surface 30b other than the vicinity of the entrance surface 30a. Therefore, it is possible to increase the light guided through the light guide 35 and improve the luminance of the entire emission surface 30b.
  • the light P10 incident on the exit surface 30b near the entrance surface 30a at an incident angle smaller than the critical angle ⁇ 1 is emitted from the exit surface 30b.
  • the light shielding member 26 is disposed on the exit surface 30b in the vicinity of the incident surface 30a, the light P10 is absorbed by the light shielding member 26. This prevents the luminance of the exit surface 30b near the entrance surface 30a from becoming higher than the brightness of the exit surface 30b other than the vicinity of the entrance surface 30a.
  • FIG. 7 is a comparative example of the illumination device 20 of the present embodiment, and shows a cross-sectional view in which the vicinity of the incident surface 30a of the light guide plate 30 is enlarged and perpendicular to the incident surface 30a.
  • the reflecting member 60 is omitted from this embodiment.
  • Part of the light P4 and P5 emitted from the light source 21 does not go in the direction of the incident surface 30a, but goes in the direction of the low refractive index layer 36 and the condensing part 37, respectively.
  • the reflecting member 60 since the reflecting member 60 is not provided, part of the light P4 and P5 emitted from the light source 21 is directly incident on the low refractive index layer 36 and the condensing unit 37 from the side end faces 36a and 37a, respectively.
  • the light P4 that is directly incident on the low refractive index layer 36 from the light source 21 is transmitted through the low refractive index layer 36 and is incident on the light collecting portion 37 in the vicinity of the incident surface 30a.
  • the light P4 incident on the condensing unit 37 from the low refractive index layer 36 and the light P5 directly incident on the condensing unit 37 are incident on the inclined surface 38b of the prism 38 near the incident surface 30a.
  • Light incident on the inclined surface 38b at an incident angle larger than the critical angle ⁇ 3 is totally reflected in the direction of the exit surface 30b.
  • Light incident on the inclined surface 38b at an incident angle smaller than the critical angle ⁇ 3 is refracted and emitted from the light collecting portion 37, and refracted from the vertical surface 38a and incident again.
  • the light P7 is absorbed by the light shielding member 26, and the light P6 is not absorbed by the light shielding member 26 but is emitted from the emission surface 30b in the vicinity of the inner periphery of the light shielding member 26.
  • the lights P6 and P7 do not guide the light guide plate 30 in the direction away from the incident surface 30a (Y direction). Therefore, the light guide plate 30 of the comparative example that does not include the reflecting member 60 cannot improve the luminance of the entire emission surface 30b as compared with the light guide plate 30 of the present embodiment.
  • the light guide plate 30 of the comparative example more light is emitted from the light exit surface 30b near the inner periphery of the light shielding member 26 as in the light P6 than in the light guide plate 30 of the present embodiment. For this reason, luminance unevenness of the illumination light emitted from the emission surface 30b occurs. At this time, since the emission surface 30b in the vicinity of the inner periphery of the light shielding member 26 faces the peripheral portion of the display area A (see FIG. 2), the display quality of the display device 1 is degraded.
  • the light emitted from the light source 21 does not directly enter the low refractive index layer 36 and the light condensing unit 37, and enters the light guide plate 30 from the incident surface 30a.
  • the light P6 and P7 that are directly incident on the low refractive index layer 36 and the condensing unit 37 from the light source 21 and then reflected by the condensing unit 37 and emitted from the exit surface 30b near the entrance surface 30a can be reduced.
  • the amount of light guided in the direction away from the incident surface 30a in the light guide plate 30 can be increased, and the luminance of the entire emission surface 30b can be improved.
  • the luminance unevenness of the illumination light emitted from the emission surface 30b can be reduced, and the display quality of the display device 1 can be improved.
  • the luminance ratio (X1 / X2) could be reduced by about 17 points as compared with the comparative example. From this result, it has been found that the luminance unevenness of the illumination light emitted from the exit surface 30b can be reduced by suppressing the increase in the brightness of the exit surface 30b near the entrance surface 30a by the reflecting member 60.
  • the light guide plate 30 includes the light guide portion 35 in which the first prism 33 including the incident surface 30 a and the emission surface 30 b and including the first inclined surface 33 b is arranged in parallel in the optical axis direction of the light source 21.
  • a low refractive index layer 36 having a refractive index smaller than that of the light guide portion 35 adjacent to the back surface of the light portion 35, and a second inclined surface formed on a surface opposite to the emission surface 30b with respect to the low refractive index layer 36. It has the condensing part 37 which arranged the 2nd prism 38 including the surface 38b in the optical axis direction of the light source 21 side by side.
  • the directivity angle of the light emitted from the emission surface 30b can be narrowed down to the direction (Y direction) orthogonal to the ridgelines of the prisms 33 and 38. Therefore, it is not necessary to provide a prism sheet or the like on the emission surface 30b, and the number of parts and the number of manufacturing steps can be reduced. As a result, the manufacturing cost of the lighting device 20 can be reduced.
  • the reflecting member 60 (first light) is arranged in contact with the side surface 36a, 37a on the light source 21 side of the low refractive index layer 36 and the condensing part 37 and reflects the emitted light of the light source 21 to guide the incident surface 30a. (Reflection part) is provided. As a result, the light emitted from the light source 21 enters the light guide plate 30 from the incident surface 30a without directly entering the low refractive index layer 36 and the condensing unit 37.
  • the emission light of the light source 21 from being directly incident on the low refractive index layer 36 and the light converging part 37 and then being reflected by the light converging part 37 and being emitted from the light emitting surface 30b in the vicinity of the incident surface 30a.
  • the amount of light guided in the direction away from the incident surface 30a in the light guide plate 30 can be increased, and the luminance of the entire emission surface 30b can be improved.
  • the reflective member 60 can be easily realized by an adhesive tape-like member containing a white pigment or a silver pigment.
  • the reflection member 60 when the reflection member 60 is not provided (see FIG. 7), for example, when the arrangement position of the light source 21 is shifted toward the reflection member 24 due to an impact on the illumination device 20, the low refractive index layer 36 and the light collection are emitted from the light source 21. More light is incident directly on the portion 37.
  • the reflecting member 60 since the reflecting member 60 is disposed in contact with the low refractive index layer 36 and the side end surfaces 36a, 37a on the light source 21 side of the light condensing unit 37, the arrangement of the light source 21 due to an impact on the illumination device 20, for example. Even when the position is shifted to the reflecting member 24 side, it is possible to prevent the light emitted from the light source 21 from directly entering the low refractive index layer 36 and the light condensing unit 37.
  • FIG. 8 shows a cross-sectional view perpendicular to the incident surface 30a by enlarging the vicinity of the incident surface 30a of the light guide plate 30 of the lighting device 20 of the present embodiment.
  • the same parts as those in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals.
  • This embodiment is different from the first embodiment in that the configuration of the housing 25 is changed and the reflection member 60 is omitted. Other parts are the same as those in the first embodiment.
  • An extending portion 25a (first light reflecting portion) is provided between the light source 21 and the reflecting member 24.
  • the extending portion 25 a is formed by a part of the housing 25 (see FIGS. 1 and 2), and extends from the surface of the housing 25 opposite to the light guide plate 30 toward the light guide plate 30 with respect to the light source 21. ing.
  • the extending portion 25a is in contact with the side end surfaces 36a and 37a on the light source 21 side of the low refractive index layer 36 and the condensing portion 37, and is formed of a resin molded product containing a white pigment or a silver pigment.
  • the extending portion 25a may be formed by applying a white paint or a silver paint on a base material such as metal.
  • the same effect as that of the first embodiment can be obtained.
  • casing 25 which accommodates the light source 21 and the light-guide plate 30 is provided, and the extending part 25a (1st light reflection part) is formed by making a white pigment or a silver pigment contain in a part of housing
  • the reflection member 60 becomes unnecessary, the number of parts can be reduced. Therefore, the manufacturing cost of the lighting device 20 can be reduced.
  • FIG. 9 shows a cross-sectional view perpendicular to the incident surface 30a by enlarging the vicinity of the incident surface 30a of the light guide plate 30 of the lighting device 20 of the present embodiment.
  • the same parts as those in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals.
  • This embodiment is different from the first embodiment in that a sheet-like reflecting member 61 (second light reflecting portion) is further provided.
  • the distance between the light source 21 and the incident surface 30a is longer than that in the first embodiment.
  • Other parts are the same as those in the first embodiment.
  • the reflection member 61 is disposed on the opposite side of the reflection member 60 with respect to the light source 21, and reflects part of the emitted light from the light source 21 to guide it to the incident surface 30a.
  • the reflection member 61 is formed of an adhesive tape-like member such as polyester containing a white pigment or a silver pigment, and is attached to the light receiving surface side of the display panel 10 (see FIGS. 1 and 2). Note that the material of the reflecting member 61 may be the same as or different from that of the reflecting member 60. Further, if the reflecting member 61 is disposed so as to be in contact with the side end surface of the light shielding member 26 on the light source 21 side, the emitted light of the light source 21 can be more reliably guided to the incident surface 30a. Further, as in the second embodiment, the reflecting member 61 may be formed by containing a white pigment or a silver pigment in a part of the housing 25.
  • the reflecting member 60 Since the reflecting member 60 is disposed in contact with the low refractive index layer 36 and the light collecting portion 37, a part P21 of the light emitted from the light source 21 enters the reflecting member 60, and the low refractive index layer 36 and the light collecting light are collected. It does not enter the part 37 directly.
  • the light P22 reflected by the reflecting member 60 enters the light guide 35 from the incident surface 30a.
  • the light P23 that has entered the light guide 35 is guided in a direction away from the incident surface 30a and is emitted from the exit surface 30b other than the vicinity of the incident surface 30a. Accordingly, it is possible to improve the luminance of the entire emission surface 30b.
  • a part P 31 of the light emitted from the light source 21 enters the reflecting member 61.
  • the light P32 reflected by the reflecting member 61 enters the light guide 35 from the incident surface 30a.
  • the light P33 incident on the light guide 35 is guided in a direction away from the incident surface 30a (Y direction) and emitted from the emission surface 30b other than the vicinity of the incident surface 30a.
  • the light guide plate 30 can be prevented from being deformed or damaged due to heat generated by the light source 21.
  • a top view type LED or a cold cathode fluorescent lamp (CCFL: Cold Cathode Fluorescent Lamp) having a large calorific value can be used as the light source 21. Therefore, the freedom degree of design of the illuminating device 20 can be improved.
  • a reflection member 61 (second light reflection portion) that is disposed on the opposite side of the light source 21 from the reflection member 60 (first light reflection portion) and reflects the light emitted from the light source 21 and guides it to the incident surface 30a. Since it is provided, the distance between the light source 21 and the incident surface 30a can be made longer than in the first embodiment. Thereby, the light guide plate 30 can be prevented from being deformed or damaged due to heat generated by the light source 21.
  • the prism 33 may be provided at the interface between the light guide 35 and the low refractive index layer 36. Further, the prism 32 may be provided so as to protrude from the light exit surface 30 b of the light guide plate 30.
  • a linear light source such as a cold cathode fluorescent lamp having a wide emission range may be used as the light source 21. Even in this case, the same effects as those of the first to third embodiments can be obtained.
  • the color of the pigment contained in the reflecting members 60 and 61 may be a light color having a high light reflectance, and for example, a yellow pigment or the like may be used.
  • the illuminating device 20 may be used as a lighting fixture which illuminates indoor or the outdoors.
  • a lighting device such as a lighting device or a lighting fixture provided with a light guide plate
  • a display device such as a liquid crystal display device using the lighting device.

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Abstract

Provided are an illumination device in which the luminance of the entire emission surface can be improved, and a display device using said illumination device. This illumination device (20) comprises: a light source (21); and a light guide plate (30) that has, on a side end surface, an entrance surface (30a) opposing the light source (21), and that guides light having entered from the entrance surface (30a) and emits illumination light from an emission surface (30b) arranged on the front surface. The light guide plate (30) includes: a light guide part (35) that has said entrance surface (30a) and said emission surface (30b) and in which first prisms (33) each having a first inclined surface (33b) are juxtaposed along the optical axis direction of the light source (21); a low-refractive-index layer (36) that is adjacent to the rear surface of the light guide part (35) and that has a lower refractive index than the light guide part (35); and a light gathering part (37) that is formed on a surface on the opposite side from the emission surface (30b) with respect to the low-refractive-index layer (36), and in which second prisms (38) each having a second inclined surface (38b) are juxtaposed along the optical axis direction of the light source (21). A reflective member (60) that reflects light emitted by the light source (21) and guides the light to the entrance surface (30a) is provided, the reflective member being arranged so as to contact the side end surfaces (36a, 37a) of the low-refractive-index layer (36) and the light gathering part (37) on the side of the light source (21).

Description

照明装置及びそれを備えた表示装置Illumination device and display device including the same
　本発明は、導光板を有する照明装置及びそれを備えた表示装置に関する。 The present invention relates to a lighting device having a light guide plate and a display device including the same.
　従来の表示装置は特許文献１に開示されている。この表示装置は照明装置と液晶表示パネルとを備える。照明装置から出射された照明光により液晶表示パネルを照射して画像が表示される。 A conventional display device is disclosed in Patent Document 1. This display device includes an illumination device and a liquid crystal display panel. An image is displayed by irradiating the liquid crystal display panel with illumination light emitted from the illumination device.
　照明装置は、蛍光ランプからなる光源、導光板、拡散シート、反射シート及びランプリフレクタを有する。導光板は前面及び背面が平面に形成された平面視略矩形の樹脂成形品から成り、光源に対向する入射面を側面に有して前面に照明光の出射面が形成される。光源から出射された光が導光板の入射面から入射して導光し、導光板の出射面から照明光が出射される。 The lighting device has a light source including a fluorescent lamp, a light guide plate, a diffusion sheet, a reflection sheet, and a lamp reflector. The light guide plate is made of a resin molded product having a substantially rectangular shape in plan view with the front surface and the back surface formed flat. The light guide plate has an incident surface facing the light source on the side surface, and an exit surface for illumination light is formed on the front surface. Light emitted from the light source enters from the incident surface of the light guide plate and is guided, and illumination light is emitted from the output surface of the light guide plate.
　拡散シートは導光板の出射面に対向して配され、出射面から出射された光を拡散する。反射シートは導光板の背面に対向して配され、導光板の背面から出射される光を反射して導光板に戻す。ランプリフレクタは光源を包囲するように配され、光源から出射された光を導光板の入射面に向けて反射する。 The diffusion sheet is arranged to face the exit surface of the light guide plate and diffuses the light emitted from the exit surface. The reflection sheet is disposed to face the back surface of the light guide plate, reflects light emitted from the back surface of the light guide plate, and returns the light to the light guide plate. The lamp reflector is arranged so as to surround the light source, and reflects the light emitted from the light source toward the incident surface of the light guide plate.
　ランプリフレクタの一端部は黒色顔料を含有した両面粘着テープによって導光板の入射面近傍の出射面に接着され、他端部は反射シートの背面側に配される。反射シートの一端部は黒色顔料を含有した両面粘着テープによって導光板の入射面近傍の背面に接着される。これにより、導光板の出射面及び背面に配された両面粘着テープの光源側の側端面は光源に対して露出する。 One end of the lamp reflector is adhered to the exit surface near the entrance surface of the light guide plate by a double-sided adhesive tape containing a black pigment, and the other end is disposed on the back side of the reflection sheet. One end of the reflection sheet is bonded to the back surface near the incident surface of the light guide plate by a double-sided adhesive tape containing a black pigment. Thereby, the side end surface by the side of the light source of the double-sided adhesive tape distribute | arranged to the output surface and back surface of a light-guide plate is exposed with respect to a light source.
　上記構成の照明装置を駆動させると、光源から出射された光は導光板の入射面から導光板内に入射する。そして、導光板の入射面近傍の出射面及び導光板の入射面近傍の背面に到達した光は両面粘着テープによって吸収される。これにより、入射面近傍の出射面の輝度が入射面近傍以外の出射面の輝度よりも著しく高くなることを防止できる。従って、出射面から出射される照明光の輝度ムラを低減できる。 When the illuminating device having the above configuration is driven, light emitted from the light source enters the light guide plate from the incident surface of the light guide plate. And the light which reached | attained the output surface near the entrance plane of a light-guide plate, and the back surface near the entrance plane of a light-guide plate is absorbed by a double-sided adhesive tape. Thereby, it is possible to prevent the luminance of the exit surface near the entrance surface from becoming significantly higher than the brightness of the exit surface other than the vicinity of the entrance surface. Therefore, it is possible to reduce uneven brightness of illumination light emitted from the emission surface.
特開平９－３２９７１０号公報（第３頁、第１図～第３図）Japanese Patent Laid-Open No. 9-329710 (page 3, FIGS. 1 to 3)
　しかしながら、上記従来の表示装置の照明装置によると、光源から出射された光の一部は入射面に入射することなく両面粘着テープの光源側の側端面に直接入射し、両面粘着テープによって吸収される。このため、光源から出射された光の一部は導光板内を導光できず、導光板内を導光する光が減少する。従って、照明装置の出射面全体の輝度が低下するという問題があった。 However, according to the illumination device of the conventional display device, a part of the light emitted from the light source is directly incident on the light source side side end surface of the double-sided adhesive tape without being incident on the incident surface, and is absorbed by the double-sided adhesive tape. The For this reason, a part of the light emitted from the light source cannot be guided in the light guide plate, and the light guided in the light guide plate is reduced. Therefore, there has been a problem that the luminance of the entire exit surface of the illumination device is reduced.
　本発明は、出射面全体の輝度を向上できる照明装置及びそれを備えた表示装置を提供することを目的とする。 An object of the present invention is to provide an illuminating device capable of improving the luminance of the entire emission surface and a display device including the illuminating device.
　上記目的を達成するために本発明は、光源と、前記光源に対向する入射面を側端面に有するとともに前記入射面から入射した光を導光して前面に配される出射面から照明光を出射する導光板とを備えた照明装置において、前記導光板が、前記入射面及び前記出射面を有するとともに第１傾斜面を含む第１プリズムを前記光源の光軸方向に並設した導光部と、前記導光部の背面に隣接して前記導光部よりも屈折率の小さい低屈折率層と、前記低屈折率層に対して前記出射面と反対側の面に形成されるとともに第２傾斜面を含む第２プリズムを前記光軸方向に並設した集光部とを有し、前記低屈折率層及び前記集光部の前記光源側の側端面に接して配されるとともに前記光源の出射光を反射して前記入射面に導く第１光反射部を設けたことを特徴としている。 In order to achieve the above object, the present invention has a light source and an incident surface facing the light source at a side end surface, and guides light incident from the incident surface to emit illumination light from an exit surface arranged on the front surface. In a lighting device including a light guide plate that emits light, the light guide plate includes a first prism that includes the incident surface and the light exit surface and includes a first inclined surface in the optical axis direction of the light source. And a low refractive index layer having a refractive index smaller than that of the light guide portion adjacent to the back surface of the light guide portion, and a surface opposite to the exit surface with respect to the low refractive index layer. A second prism including two inclined surfaces arranged in parallel in the optical axis direction, arranged in contact with the light source side side end surface of the low refractive index layer and the light collecting portion, and A first light reflecting portion for reflecting the light emitted from the light source and guiding it to the incident surface is provided. It is set to.
　この構成によると、光源から出射された光は入射面から導光板の導光部に入射する。導光部に入射した光は前面の出射面及び背面で反射して導光する。導光部の導光は第１傾斜面での反射によって出射面及び背面の入射角が徐々に大きくなる。導光部の背面に臨界角よりも小さい入射角で入射した光は低屈折率層に入射する。この時、第１傾斜面で反射して入射角が臨界角よりも小さくなった光が低屈折率層に入射し、臨界角よりも大きい光は第１傾斜面で再度反射して入射角が臨界角よりも小さくなると低屈折率層に入射する。これにより、低屈折率層に入射する光の入射角は第１傾斜面の傾斜角に応じて所定範囲に絞られる。低屈折率層に入射して第２傾斜面に臨界角よりも大きい入射角で入射した光は出射面の方向に反射し、導光部を透過して出射面から出射される。また、第２傾斜面に臨界角よりも小さい入射角で入射した光は集光部から出射する際に第２傾斜面で屈折し、集光部に再度入射する。そして、第２傾斜面の入射角が臨界角よりも大きくなると出射面の方向に反射する。この時、光源から出射された光の一部は第１光反射部で反射して入射面から導光部に入射する。 According to this configuration, the light emitted from the light source enters the light guide portion of the light guide plate from the incident surface. The light incident on the light guide unit is reflected and guided by the front exit surface and the back surface. In the light guide of the light guide unit, the incident angles on the exit surface and the back surface gradually increase due to reflection on the first inclined surface. Light incident on the back surface of the light guide unit at an incident angle smaller than the critical angle enters the low refractive index layer. At this time, light reflected by the first inclined surface and having an incident angle smaller than the critical angle is incident on the low refractive index layer, and light larger than the critical angle is reflected again by the first inclined surface and the incident angle is reduced. When the angle is smaller than the critical angle, the light enters the low refractive index layer. Thereby, the incident angle of the light incident on the low refractive index layer is reduced to a predetermined range according to the inclination angle of the first inclined surface. Light incident on the low refractive index layer and incident on the second inclined surface at an incident angle larger than the critical angle is reflected in the direction of the exit surface, passes through the light guide, and exits from the exit surface. In addition, light incident on the second inclined surface with an incident angle smaller than the critical angle is refracted by the second inclined surface when exiting from the condensing unit, and is incident on the condensing unit again. And when the incident angle of a 2nd inclined surface becomes larger than a critical angle, it will reflect in the direction of an output surface. At this time, part of the light emitted from the light source is reflected by the first light reflecting portion and enters the light guide portion from the incident surface.
　また本発明は、上記構成の照明装置において、前記光源と前記導光板とを収納する筐体を備え、前記筐体に白色顔料または銀色顔料を含有させることにより第１光反射部を形成すると好ましい。この構成によると、光源から出射された光の一部は筐体で反射して入射面から導光部に入射する。 In the lighting device having the above-described configuration, the present invention preferably includes a housing that houses the light source and the light guide plate, and the first light reflecting portion is formed by containing a white pigment or a silver pigment in the housing. . According to this configuration, a part of the light emitted from the light source is reflected by the casing and enters the light guide unit from the incident surface.
　また本発明は、上記構成の照明装置において、白色顔料または銀色顔料を含有した粘着テープ状部材により第１光反射部を形成すると好ましい。この構成によると、光源から出射された光の一部は粘着テープ状部材で反射して入射面から導光部に入射する。 In the lighting device having the above-described configuration, it is preferable that the first light reflecting portion is formed of an adhesive tape-like member containing a white pigment or a silver pigment. According to this configuration, a part of the light emitted from the light source is reflected by the adhesive tape-like member and enters the light guide unit from the incident surface.
　また本発明は、上記構成の照明装置において、前記光源に対して第１光反射部と反対側に配されるとともに前記光源の出射光を反射して前記入射面に導く第２光反射部をさらに備えるとより好ましい。この構成によると、光源から出射された光の一部は第２光反射部で反射して入射面から導光部に入射する。 According to the present invention, in the illumination device having the above-described configuration, a second light reflecting portion that is arranged on the opposite side of the first light reflecting portion with respect to the light source and reflects the emitted light of the light source to guide the incident surface. It is more preferable to provide further. According to this configuration, part of the light emitted from the light source is reflected by the second light reflecting portion and enters the light guide portion from the incident surface.
　また本発明の表示装置は、上記各構成の照明装置と、前記導光板の前記出射面に対向して配置される表示パネルとを備えたことを特徴としている。 Further, the display device of the present invention is characterized by including the illumination device having the above-described configuration and a display panel disposed to face the emission surface of the light guide plate.
　本発明によると、導光板が、入射面及び出射面を有する導光部と、導光部の背面に隣接する低屈折率層と、低屈折率層に対して出射面と反対側の面に形成される集光部とを有し、低屈折率層及び集光部の光源側の側端面に接して配されるとともに光源の出射光を反射して入射面に導く第１光反射部を設けている。これにより、光源から出射された光は低屈折率層及び集光部に直接入射することなく、入射面から導光板内に入射する。従って、光源の出射光が低屈折率層及び集光部に直接入射した後に集光部で反射して入射面近傍の出射面から出射されることを低減できる。その結果、導光板内を入射面から離れる方向に導光する光を多くすることができ、出射面全体の輝度を向上させることができる。 According to the present invention, the light guide plate has a light guide portion having an entrance surface and an exit surface, a low refractive index layer adjacent to the back surface of the light guide portion, and a surface opposite to the exit surface with respect to the low refractive index layer. A first light reflecting portion that is disposed in contact with the side surface on the light source side of the low refractive index layer and the light collecting portion and that reflects the emitted light of the light source and guides it to the incident surface. Provided. Thereby, the light emitted from the light source enters the light guide plate from the incident surface without directly entering the low refractive index layer and the condensing part. Therefore, it can be reduced that the light emitted from the light source is directly incident on the low refractive index layer and the light converging part and then reflected by the light converging part and emitted from the light emitting surface near the incident surface. As a result, the amount of light guided in the direction away from the incident surface in the light guide plate can be increased, and the luminance of the entire emission surface can be improved.
本発明の第１実施形態の表示装置を示す斜視図The perspective view which shows the display apparatus of 1st Embodiment of this invention. 本発明の第１実施形態の表示装置を示す側面断面図Side surface sectional drawing which shows the display apparatus of 1st Embodiment of this invention. 本発明の第１実施形態の表示装置の照明装置の導光板を示す斜視図The perspective view which shows the light-guide plate of the illuminating device of the display apparatus of 1st Embodiment of this invention. 本発明の第１実施形態の表示装置の照明装置の導光板の入射面に垂直な断面を示す断面図Sectional drawing which shows a cross section perpendicular | vertical to the entrance plane of the light-guide plate of the illuminating device of the display apparatus of 1st Embodiment of this invention. 本発明の第１実施形態の表示装置の照明装置の導光板の集光部の入射面に垂直な断面を示す断面図Sectional drawing which shows a cross section perpendicular | vertical to the entrance plane of the condensing part of the light-guide plate of the illuminating device of the display apparatus of 1st Embodiment of this invention. 本発明の第１実施形態の表示装置の照明装置の導光板の入射面近傍を拡大して入射面に垂直な断面を示す断面図Sectional drawing which expands the entrance plane vicinity of the light-guide plate of the illuminating device of the display apparatus of 1st Embodiment of this invention, and shows a cross section perpendicular | vertical to an entrance plane 本発明の第１実施形態の表示装置の照明装置の比較例であって導光板の入射面近傍を拡大して入射面に垂直な断面を示す断面図Sectional drawing which is a comparative example of the illuminating device of the display apparatus of 1st Embodiment of this invention, and expands the entrance plane vicinity of a light-guide plate, and shows a cross section perpendicular | vertical to an entrance plane 本発明の第２実施形態の表示装置の照明装置の導光板の入射面近傍を拡大して入射面に垂直な断面を示す断面図Sectional drawing which expands the entrance plane vicinity of the light-guide plate of the illuminating device of the display apparatus of 2nd Embodiment of this invention, and shows a cross section perpendicular | vertical to an entrance plane 本発明の第３実施形態の表示装置の照明装置の導光板の入射面近傍を拡大して入射面に垂直な断面を示す断面図Sectional drawing which expands the entrance plane vicinity of the light-guide plate of the illuminating device of the display apparatus of 3rd Embodiment of this invention, and shows a cross section perpendicular | vertical to an entrance plane
　以下に本発明の実施形態を図面を参照して説明する。図１、図２は第１実施形態の表示装置を示す斜視図及び側面断面図である。表示装置１は表示パネル１０と照明装置２０とを備えている。表示パネル１０は液晶表示パネルから成り、薄膜トランジスタ（ＴＦＴ：Ｔｈｉｎ　Ｆｉｌｍ　Ｔｒａｎｓｉｓｔｏｒ）等のスイッチング素子を含むアクティブマトリックス基板１１と、アクティブマトリックス基板１１に対向する対向基板１２とを有する。アクティブマトリックス基板１１と対向基板１２との間には液晶１４が注入される。アクティブマトリックス基板１１の受光面側及び対向基板１２の出射面側にはそれぞれ偏光フィルム１３が配される。 Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a perspective view and a side sectional view showing the display device of the first embodiment. The display device 1 includes a display panel 10 and a lighting device 20. The display panel 10 includes a liquid crystal display panel, and includes an active matrix substrate 11 including a switching element such as a thin film transistor (TFT: Thin Film Transistor), and a counter substrate 12 facing the active matrix substrate 11. Liquid crystal 14 is injected between the active matrix substrate 11 and the counter substrate 12. A polarizing film 13 is disposed on each of the light receiving surface side of the active matrix substrate 11 and the light emitting surface side of the counter substrate 12.
　液晶表示パネル１０は表示領域Ａと非表示領域ＮＡとを有する。表示領域Ａは画像を表示する領域であり、非表示領域ＮＡは画像を表示しない領域である。非表示領域ＮＡは表示領域Ａの周囲に形成される。 The liquid crystal display panel 10 has a display area A and a non-display area NA. The display area A is an area for displaying an image, and the non-display area NA is an area for not displaying an image. The non-display area NA is formed around the display area A.
　照明装置２０は筐体２５、光源２１及び導光板３０を備える。筐体２５は中央部が開口した枠状に形成され、光源２１及び導光板３０を収納する。筐体２５の下面の開口部はシート状の反射部材２４により覆われる。筐体２５は黒色顔料を含有した樹脂成形品等の光吸収材により形成される。樹脂や金属等の基材上に黒色塗料等の光吸収材を塗布して筐体２５を形成してもよい。光源２１はＬＥＤ（発光ダイオード：Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）から成り、複数の光源２１が一方向（Ｘ方向）に並設される。 The lighting device 20 includes a housing 25, a light source 21, and a light guide plate 30. The housing 25 is formed in a frame shape with an open center, and houses the light source 21 and the light guide plate 30. The opening on the lower surface of the housing 25 is covered with a sheet-like reflecting member 24. The housing 25 is formed of a light absorbing material such as a resin molded product containing a black pigment. The housing 25 may be formed by applying a light absorbing material such as a black paint on a base material such as resin or metal. The light source 21 is composed of an LED (Light Emitting Diode), and a plurality of light sources 21 are arranged in one direction (X direction).
　導光板３０は透明樹脂等によって平面視矩形形状に形成される。導光板３０の側面は光源２１に対向して光源２１の出射光が入射する入射面３０ａを形成し、表示パネル１０に対向する前面は照明光を出射する出射面３０ｂを形成する。 The light guide plate 30 is formed in a rectangular shape in plan view with a transparent resin or the like. The side surface of the light guide plate 30 faces the light source 21 to form an incident surface 30a on which light emitted from the light source 21 enters, and the front surface facing the display panel 10 forms an output surface 30b that emits illumination light.
　以下の説明において、入射面３０ａの長手方向をＸ方向、Ｘ方向に直交する光源２１の光軸方向をＹ方向、Ｘ方向及びＹ方向に直交する導光板３０の出射方向をＺ方向とする。 In the following description, the longitudinal direction of the incident surface 30a is the X direction, the optical axis direction of the light source 21 orthogonal to the X direction is the Y direction, and the emission direction of the light guide plate 30 orthogonal to the X direction and the Y direction is the Z direction.
　反射部材２４は導光板３０の背面から出射される光を反射して導光板３０内に戻す。反射部材２４によって光の利用効率を向上させることができる。 The reflection member 24 reflects the light emitted from the back surface of the light guide plate 30 and returns it to the light guide plate 30. The light utilization efficiency can be improved by the reflecting member 24.
　導光板３０の出射面３０ｂの周部にはシート状の遮光部材２６が配される。遮光部材２６は中央部が開口した枠状に形成され、非表示領域ＮＡに対向して配置されている。遮光部材２６は例えばポリエステル（ＰＥＴ：Ｐｏｌｙｅｓｔｅｒ）により形成され、黒色顔料を含有している。遮光部材２６の片面には粘着剤（不図示）が配され、粘着剤により遮光部材２６は出射面３０ｂに貼着される。なお、両面に粘着剤を配した両面粘着テープにより遮光部材２６を形成してもよい。 A sheet-shaped light shielding member 26 is disposed on the periphery of the light exit surface 30 b of the light guide plate 30. The light shielding member 26 is formed in a frame shape having an opening at the center, and is disposed to face the non-display area NA. The light shielding member 26 is made of, for example, polyester (PET: Polyester) and contains a black pigment. An adhesive (not shown) is disposed on one side of the light shielding member 26, and the light shielding member 26 is adhered to the emission surface 30b by the adhesive. In addition, you may form the light shielding member 26 with the double-sided adhesive tape which has arrange | positioned the adhesive on both surfaces.
　図３、図４は照明装置２０の導光板３０の斜視図及び側面断面図を示している。導光板３０はＺ方向に積層された導光部３５、低屈折率層３６及び集光部３７を有している。導光部３５はアクリルやポリカーボネート等の透明樹脂等により形成され、入射面３０ａ及び出射面３０ｂを有して光源２１から入射した光を導光する。 3 and 4 show a perspective view and a side sectional view of the light guide plate 30 of the lighting device 20. The light guide plate 30 includes a light guide part 35, a low refractive index layer 36, and a light collecting part 37 stacked in the Z direction. The light guide 35 is formed of a transparent resin such as acrylic or polycarbonate, and has an incident surface 30a and an output surface 30b, and guides light incident from the light source 21.
　導光部３５の屈折率ｎ１は１．４２以上であるのが好ましく、１．５９～１．６５であればより好ましい。導光部３５をアクリルにより形成すると、屈折率ｎ１を約１．４９にすることができる。また、導光部３５をポリカーボネートにより形成すると、屈折率ｎ１を約１．５９にすることができる。導光部３５をアクリルにより形成すると、ポリカーボネートにより形成した場合に比して透光性をより向上させることができる。 The refractive index n1 of the light guide 35 is preferably 1.42 or more, more preferably 1.59 to 1.65. When the light guide 35 is made of acrylic, the refractive index n1 can be about 1.49. Further, when the light guide part 35 is made of polycarbonate, the refractive index n1 can be about 1.59. If the light guide part 35 is formed of acrylic, the translucency can be further improved as compared with the case where it is formed of polycarbonate.
　導光部３５の出射面３０ｂにはＹ方向に延びる複数のプリズム３２（第３プリズム）がＸ方向に並設される。プリズム３２は出射面３０ｂ上に凹設され、円弧、楕円弧その他の曲線や三角形等の断面形状を有している。 A plurality of prisms 32 (third prisms) extending in the Y direction are juxtaposed in the X direction on the emission surface 30 b of the light guide 35. The prism 32 is recessed on the exit surface 30b and has a cross-sectional shape such as an arc, an elliptical arc, other curves, or a triangle.
　光源２１から出射して入射面３０ａから入射した光はプリズム３２によって入射面３０ａの長手方向（Ｘ方向）に拡散して反射される。これにより、点発光するＬＥＤから成る複数の光源２１から入射した光をＸ方向に拡散して照明光を均一化することができる。なお、光源２１が入射面３０ａの長手方向に延びる線状に形成される場合はプリズム３２を省いてもよい。 The light emitted from the light source 21 and incident from the incident surface 30a is diffused and reflected by the prism 32 in the longitudinal direction (X direction) of the incident surface 30a. Thereby, the incident light can be made uniform by diffusing the light incident from the plurality of light sources 21 composed of LEDs that emit point light in the X direction. When the light source 21 is formed in a linear shape extending in the longitudinal direction of the incident surface 30a, the prism 32 may be omitted.
　導光板３０の出射面３０ｂの隣接するプリズム３２間には、Ｙ方向に並設される複数のプリズム３３（第１プリズム）が設けられる。Ｙ方向に隣接するプリズム３３間にはＸ－Ｙ面に平行な水平面３４が設けられる。なお、プリズム３３を連続して形成して水平面３４を省いてもよい。 A plurality of prisms 33 (first prisms) arranged in the Y direction are provided between the adjacent prisms 32 on the light exit surface 30 b of the light guide plate 30. A horizontal plane 34 parallel to the XY plane is provided between the prisms 33 adjacent in the Y direction. The prism 33 may be formed continuously and the horizontal plane 34 may be omitted.
　プリズム３３はＸ－Ｙ面に垂直な垂直面３３ａとＹ－Ｚ面内で傾斜した傾斜面３３ｂ（第１傾斜面）とを有している。傾斜面３３ｂは入射面３０ａから離れるに従って低屈折率層３６に近づく方向に傾斜し、入射面３０ａに直交する方向（Ｙ方向）に対して所定の傾斜角βを有する。傾斜角βは５°以下の角度であるのが好ましく、０．１°～３°の角度であればより好ましい。また、傾斜面３３ｂのＹ方向の長さは０．２５ｍｍ以下であるのが好ましく、０．０１ｍｍ～０．１０ｍｍであればより好ましい。 The prism 33 has a vertical surface 33a perpendicular to the XY plane and an inclined surface 33b (first inclined surface) inclined in the YZ plane. The inclined surface 33b is inclined in a direction approaching the low refractive index layer 36 as it is away from the incident surface 30a, and has a predetermined inclination angle β with respect to a direction (Y direction) orthogonal to the incident surface 30a. The inclination angle β is preferably an angle of 5 ° or less, more preferably an angle of 0.1 ° to 3 °. The length of the inclined surface 33b in the Y direction is preferably 0.25 mm or less, and more preferably 0.01 mm to 0.10 mm.
　低屈折率層３６は導光部３５の背面３５ａに隣接し、導光部３５よりも低い屈折率を有している。低屈折率層３６はフッ素系のアクリレートや、ナノサイズの無機フィラー等の中空粒子が含有された樹脂等により形成される。低屈折率層３６の屈折率ｎ２は１．４２未満であるのが好ましく、１．１０～１．３５であればより好ましい。また、導光部３５の屈折率ｎ１と低屈折率層３６の屈折率ｎ２との間には、ｎ１／ｎ２＞１．１８の関係が成り立つことが好ましい。 The low refractive index layer 36 is adjacent to the back surface 35a of the light guide 35 and has a lower refractive index than the light guide 35. The low refractive index layer 36 is formed of a resin containing hollow particles such as a fluorine-based acrylate or a nano-sized inorganic filler. The refractive index n2 of the low refractive index layer 36 is preferably less than 1.42, more preferably 1.10 to 1.35. Further, it is preferable that a relationship of n1 / n2> 1.18 is established between the refractive index n1 of the light guide 35 and the refractive index n2 of the low refractive index layer 36.
　低屈折率層３６をフッ素系のアクリレートにより形成すると、屈折率ｎ２を約１．３５にすることができる。低屈折率層３６を中空粒子を含有した樹脂により形成すると、屈折率ｎ２を１．３０以下にすることができる。 When the low refractive index layer 36 is formed of a fluorine-based acrylate, the refractive index n2 can be about 1.35. When the low refractive index layer 36 is formed of a resin containing hollow particles, the refractive index n2 can be made 1.30 or less.
　集光部３７は低屈折率層３６に隣接し、低屈折率層３６に対して同じまたは大きい屈折率を有している。従って、集光部３７を低屈折率層３６と同一部材により形成してもよい。 The condensing part 37 is adjacent to the low refractive index layer 36 and has the same or larger refractive index than the low refractive index layer 36. Therefore, the condensing part 37 may be formed of the same member as the low refractive index layer 36.
　集光部３７の背面にはＸ方向に延びてＹ方向に並設される複数のプリズム３８（第２プリズム）が設けられる。図５は集光部３７の入射面３０ａに垂直な断面図を示している。プリズム３８はＸ－Ｙ面に垂直な垂直面３８ａとＹ－Ｚ面内で傾斜した傾斜面３８ｂ（第２傾斜面）とを有している。傾斜面３８ｂは入射面３０ａから離れるに従って低屈折率層３６に近づく方向に傾斜し、Ｚ方向に対して所定の傾斜角γを有する。 A plurality of prisms 38 (second prisms) extending in the X direction and juxtaposed in the Y direction are provided on the back surface of the light collecting unit 37. FIG. 5 shows a cross-sectional view perpendicular to the incident surface 30 a of the light collecting portion 37. The prism 38 has a vertical surface 38a perpendicular to the XY plane and an inclined surface 38b (second inclined surface) inclined in the YZ plane. The inclined surface 38b is inclined in a direction approaching the low refractive index layer 36 as the distance from the incident surface 30a increases, and has a predetermined inclination angle γ with respect to the Z direction.
　傾斜面３８ｂのＹ方向の長さは約０．１ｍｍ以下であり、約０．０１ｍｍ～約０．０２５ｍｍであることが好ましい。傾斜角γはプリズム３８の頂角となり、４０°～５０゜であるのが好ましい。なお、垂直面３８ａをＹ方向に対して傾斜して形成してもよい。この時、プリズム３８の頂角を４０°～５０゜にするとよい。 The length of the inclined surface 38b in the Y direction is about 0.1 mm or less, preferably about 0.01 mm to about 0.025 mm. The inclination angle γ is the apex angle of the prism 38, and is preferably 40 ° to 50 °. The vertical surface 38a may be formed inclined with respect to the Y direction. At this time, the apex angle of the prism 38 may be set to 40 ° to 50 °.
　低屈折率層３６及び集光部３７の光源２１側の側端面３６ａ、３７ａに接するようにシート状の反射部材６０（第１光反射部）が配される。反射部材６０は光源２１の出射光の一部（雑光）を反射して入射面３０ａに導く。 The sheet-like reflecting member 60 (first light reflecting portion) is disposed so as to be in contact with the side surfaces 36a and 37a on the light source 21 side of the low refractive index layer 36 and the light collecting portion 37. The reflecting member 60 reflects a part of the light emitted from the light source 21 (miscellaneous light) and guides it to the incident surface 30a.
　反射部材６０は白色顔料または銀色顔料を含有したポリエステル等の粘着テープ状部材により形成され、反射部材２４の前面に貼着される。 The reflection member 60 is formed of an adhesive tape-like member such as polyester containing a white pigment or a silver pigment, and is attached to the front surface of the reflection member 24.
　また、反射部材６０の厚さ（Ｚ方向の厚さ）を低屈折率層３６及び集光部３７の厚さ（Ｚ方向の厚さ）の合計以上の厚さにするとともに、反射部材６０の幅（Ｘ方向の幅）を低屈折率層３６及び集光部３７の幅（Ｘ方向の幅）以上にすると、反射部材６０により低屈折率層３６及び集光部３７の側端面３６ａ、３７ａを完全に覆うことができる。これにより、光源２１の出射光が低屈折率層３６及び集光部３７に直接入射することをより確実に防止できる。 In addition, the thickness of the reflecting member 60 (thickness in the Z direction) is set to be equal to or greater than the total thickness of the low refractive index layer 36 and the condensing part 37 (thickness in the Z direction). When the width (width in the X direction) is equal to or greater than the width (width in the X direction) of the low refractive index layer 36 and the light collecting portion 37, the side surfaces 36 a and 37 a of the low refractive index layer 36 and the light collecting portion 37 are reflected by the reflecting member 60. Can be completely covered. Thereby, it can prevent more reliably that the emitted light of the light source 21 injects into the low refractive index layer 36 and the condensing part 37 directly.
　上記構成の表示装置１において、光源２１から出射された光は光源２１の正面方向（Ｙ方向）に最も高い強度を有し、正面方向（Ｙ方向）に対してＸ方向及びＺ方向に広がる。光源２１の出射光は導光部３５の入射面３０ａに入射する際に屈折する。この時の屈折角をθ０とし、導光部３５と空気との臨界角をφ１とすると、θ０＜φ１となる。φ１はａｒｃｓｉｎ（１／ｎ１）であり、例えば、ｎ１＝１．５９とすると、φ１＝３９゜である。すなわち、入射面３０ａから入射した光のＹ方向に対するＸ方向及びＺ方向の広がり角が±φ１になる。 In the display device 1 configured as described above, the light emitted from the light source 21 has the highest intensity in the front direction (Y direction) of the light source 21 and spreads in the X direction and the Z direction with respect to the front direction (Y direction). Light emitted from the light source 21 is refracted when entering the incident surface 30 a of the light guide 35. If the refraction angle at this time is θ0 and the critical angle between the light guide 35 and the air is φ1, θ0 <φ1. φ1 is arcsin (1 / n1). For example, if n1 = 1.59, φ1 = 39 °. That is, the spread angle in the X direction and the Z direction with respect to the Y direction of the light incident from the incident surface 30a becomes ± φ1.
　導光部３５の入射面３０ａから入射した光は出射面３０ｂと背面３５ａとの間で反射して導光する。入射面３０ａから出射面３０ｂに向かう光は水平面３４または傾斜面３３ｂに入射する。水平面３４に入射する光の入射角は９０°－φ１以上である。傾斜面３３ｂに入射する光Ｑ１の入射角θ１は９０°－φ１－β以上である。 The light incident from the incident surface 30a of the light guide part 35 is reflected and guided between the exit surface 30b and the back surface 35a. Light traveling from the incident surface 30a toward the exit surface 30b is incident on the horizontal surface 34 or the inclined surface 33b. The incident angle of light incident on the horizontal plane 34 is 90 ° −φ1 or more. The incident angle θ1 of the light Q1 incident on the inclined surface 33b is 90 ° −φ1-β or more.
　この時、出射面３０ｂに臨界角φ１よりも小さい入射角で入射した光が出射面３０ｂから出射され、臨界角φ１よりも大きい入射角で入射した光は全反射する。傾斜面３３ｂで反射した光Ｑ２は背面３５ａに入射角θ２で入射する。入射角θ２は９０°－φ１－２・β以上である。この時、導光部３５と低屈折率層３６との臨界角φ２よりも小さい入射角で背面３５ａに入射した光は低屈折率層３６に入射する。また、臨界角φ２よりも大きい入射角で背面３５ａに入射した光は全反射する。臨界角φ２＝ａｒｃｓｉｎ（ｎ２／ｎ１）であり、例えば、ｎ１＝１．５９、ｎ２＝１．３５とすると、φ２＝５８゜である。 At this time, light incident on the emission surface 30b at an incident angle smaller than the critical angle φ1 is emitted from the emission surface 30b, and light incident at an incident angle larger than the critical angle φ1 is totally reflected. The light Q2 reflected by the inclined surface 33b enters the back surface 35a at an incident angle θ2. The incident angle θ2 is 90 ° −φ1-2 · β or more. At this time, light incident on the back surface 35 a at an incident angle smaller than the critical angle φ 2 between the light guide 35 and the low refractive index layer 36 enters the low refractive index layer 36. Further, light incident on the back surface 35a at an incident angle larger than the critical angle φ2 is totally reflected. The critical angle φ2 = arcsin (n2 / n1). For example, when n1 = 1.59 and n2 = 1.35, φ2 = 58 °.
　背面３５ａで反射した光Ｑ３は出射面３０ｂに入射する。この時、水平面３４に入射する光の入射角はθ２であり、傾斜面３３ｂに入射する光の入射角θ３は９０°－φ１－３・β以上である。上記と同様に、出射面３０ｂに臨界角φ１よりも小さい入射角で入射した光が出射面３０ｂから出射され、臨界角φ１よりも大きい入射角で入射した光は全反射する。 The light Q3 reflected by the back surface 35a is incident on the exit surface 30b. At this time, the incident angle of the light incident on the horizontal plane 34 is θ2, and the incident angle θ3 of the light incident on the inclined surface 33b is 90 ° −φ1−3 · β or more. In the same manner as described above, light incident on the emission surface 30b at an incident angle smaller than the critical angle φ1 is emitted from the emission surface 30b, and light incident at an incident angle larger than the critical angle φ1 is totally reflected.
　この時、傾斜面３３ｂで反射した光Ｑ４は背面３５ａに入射角θ４で入射する。入射角θ４は９０°－φ１－４・β以上である。そして、臨界角φ２よりも小さい入射角で背面３５ａに入射した光は低屈折率層３６に入射し、臨界角φ２よりも大きい入射角で背面３５ａに入射した光は全反射する。 At this time, the light Q4 reflected by the inclined surface 33b enters the back surface 35a at an incident angle θ4. The incident angle θ4 is 90 ° −φ1−4 · β or more. The light incident on the back surface 35a with an incident angle smaller than the critical angle φ2 enters the low refractive index layer 36, and the light incident on the back surface 35a with an incident angle larger than the critical angle φ2 is totally reflected.
　すなわち、導光部３５を導光する光は傾斜面３３ｂの反射によって出射面３０ｂ及び背面３５ａの入射角が徐々に小さくなる。そして、導光部３５と低屈折率層３６との界面の入射角は２・βずつ小さくなり、臨界角φ２よりも小さくなると低屈折率層３６に入射する。このため、導光部３５から低屈折率層３６に入射する光の入射角の範囲はφ２～φ２－２・βになる。 That is, the light that is guided through the light guide 35 is gradually reduced in the incident angle of the exit surface 30b and the back surface 35a due to the reflection of the inclined surface 33b. The incident angle at the interface between the light guide 35 and the low refractive index layer 36 decreases by 2 · β, and enters the low refractive index layer 36 when it becomes smaller than the critical angle φ2. For this reason, the range of incident angles of light incident on the low refractive index layer 36 from the light guide 35 is φ2 to φ2-2 · β.
　低屈折率層３６に入射した光は低屈折率層３６を透過し、集光部３７に入射する。この時、集光部３７の屈折率ｎ３は低屈折率層３６の屈折率ｎ２に対して同じまたは大きいので、低屈折率層３６と集光部３７との界面での全反射は生じない。 The light incident on the low refractive index layer 36 passes through the low refractive index layer 36 and enters the light collecting portion 37. At this time, since the refractive index n3 of the light condensing part 37 is the same as or larger than the refractive index n2 of the low refractive index layer 36, total reflection at the interface between the low refractive index layer 36 and the light converging part 37 does not occur.
　集光部３７に入射した光はプリズム３８の傾斜面３８ｂ（図５参照）に入射する。傾斜面３８ｂに集光部３７と空気との臨界角φ３よりも大きい入射角で入射した光は出射面３０ｂの方向に全反射する。臨界角φ３＝ａｒｃｓｉｎ（１／ｎ３）である。例えば、ｎ１＝ｎ３＝１．５９とすると、φ３＝３９゜であり、ｎ１＝１．５９、ｎ２＝ｎ３＝１．３５とすると、φ３＝４８゜である。 The light incident on the condensing unit 37 enters the inclined surface 38b (see FIG. 5) of the prism 38. Light incident on the inclined surface 38b at an incident angle larger than the critical angle φ3 between the light collecting portion 37 and air is totally reflected in the direction of the exit surface 30b. The critical angle φ3 = arcsin (1 / n3). For example, when n1 = n3 = 1.59, φ3 = 39 °, and when n1 = 1.59 and n2 = n3 = 1.35, φ3 = 48 °.
　傾斜面３８ｂに臨界角φ３よりも小さい入射角で入射した光は集光部３７から屈折して出射され、垂直面３８ａから集光部３７に屈折して再度入射する。これにより、集光部３７に対して出射と入射を繰り返すと、光が屈折して傾斜面３８ｂの入射角が徐々に大きくなるため傾斜面３８ｂで全反射する。 The light incident on the inclined surface 38b at an incident angle smaller than the critical angle φ3 is refracted and emitted from the condensing unit 37, and is refracted and incident again from the vertical surface 38a to the condensing unit 37. As a result, when emission and incidence are repeated with respect to the condensing unit 37, the light is refracted and the incident angle of the inclined surface 38b gradually increases, so that the light is totally reflected by the inclined surface 38b.
　傾斜面３８ｂで反射した光は出射面３０ｂから出射される。これにより、出射面３０ｂから出射された光の指向角をプリズム３３、３８の稜線に直交する方向（Ｙ方向）に絞り込むことができる。従って、出射面３０ｂにプリズムシート等を設ける必要がなく、部品点数及び製造工数を削減できる。その結果、照明装置２０の製造コストを削減できる。 The light reflected by the inclined surface 38b is emitted from the emission surface 30b. Thereby, the directivity angle of the light emitted from the emission surface 30b can be narrowed down to the direction (Y direction) orthogonal to the ridgelines of the prisms 33 and 38. Therefore, it is not necessary to provide a prism sheet or the like on the emission surface 30b, and the number of parts and the number of manufacturing steps can be reduced. As a result, the manufacturing cost of the lighting device 20 can be reduced.
　また、図４において、入射面３０ａから導光部３５の背面３５ａに向かって進行する光Ｑ５も同様に、出射面３０ｂと背面３５ａとの間で反射を繰り返して低屈折率層３６に入射する。そして、プリズム３８の傾斜面３８ｂで反射して出射面３０ｂから出射される。 Further, in FIG. 4, similarly, the light Q5 traveling from the incident surface 30a toward the back surface 35a of the light guide 35 is repeatedly reflected between the light exit surface 30b and the back surface 35a and enters the low refractive index layer 36. . Then, the light is reflected by the inclined surface 38b of the prism 38 and is emitted from the emission surface 30b.
　上記により、導光部３５の導光の低屈折率層３６に対する入射角が２・βずつ小さくなり、順に低屈折率層３６に入射して出射面３０ｂから出射される。これにより、入射面３０ａに対向する端面３０ｃ（図４参照）から出射される光を少なくすることができる。 As described above, the incident angle of the light guide portion 35 with respect to the light guiding low refractive index layer 36 is decreased by 2 · β, and sequentially enters the low refractive index layer 36 and is emitted from the emission surface 30b. Thereby, the light radiate | emitted from the end surface 30c (refer FIG. 4) facing the entrance plane 30a can be decreased.
　このため、筐体２５を光吸収材により形成しても吸収される光が少なく、筐体２５の近傍における照明光の輝度低下を防止することができる。従って、筐体２５を薄型化して照明装置２０の狭額縁化を図り、照明装置２０及び表示装置１を小型化することができる。 For this reason, even if the housing 25 is formed of a light absorbing material, less light is absorbed, and a reduction in the luminance of illumination light in the vicinity of the housing 25 can be prevented. Accordingly, the casing 25 can be thinned to narrow the frame of the lighting device 20, and the lighting device 20 and the display device 1 can be downsized.
　図６は導光板３０の入射面３０ａ近傍を拡大して入射面３０ａに垂直な断面図を示している。反射部材６０が低屈折率層３６及び集光部３７に接して配されているため、光源２１から出射された光の一部Ｐ１は反射部材６０に入射して低屈折率層３６及び集光部３７には直接入射しない。反射部材６０で反射した光Ｐ２は入射面３０ａから導光部３５に入射する。そして、導光部３５に入射した光Ｐ３は入射面３０ａから離れる方向（Ｙ方向）に導光した後に入射面３０ａ近傍以外の出射面３０ｂから出射される。従って、導光部３５内を導光する光を多くして出射面３０ｂ全体の輝度を向上させることができる。 FIG. 6 is a cross-sectional view in which the vicinity of the incident surface 30a of the light guide plate 30 is enlarged and perpendicular to the incident surface 30a. Since the reflecting member 60 is disposed in contact with the low refractive index layer 36 and the light collecting portion 37, a part of the light P1 emitted from the light source 21 enters the reflecting member 60 and is collected by the low refractive index layer 36 and the light collecting light. It does not enter the part 37 directly. The light P2 reflected by the reflecting member 60 enters the light guide 35 from the incident surface 30a. The light P3 incident on the light guide 35 is guided in a direction away from the incident surface 30a (Y direction) and then emitted from the exit surface 30b other than the vicinity of the entrance surface 30a. Therefore, it is possible to increase the light guided through the light guide 35 and improve the luminance of the entire emission surface 30b.
　入射面３０ａ近傍の出射面３０ｂに臨界角φ１よりも小さい入射角で入射する光Ｐ１０は出射面３０ｂから出射される。この時、入射面３０ａ近傍の出射面３０ｂには遮光部材２６が配されているため、光Ｐ１０は遮光部材２６によって吸収される。これにより、入射面３０ａ近傍の出射面３０ｂの輝度が入射面３０ａ近傍以外の出射面３０ｂの輝度よりも高くなることが防止される。 The light P10 incident on the exit surface 30b near the entrance surface 30a at an incident angle smaller than the critical angle φ1 is emitted from the exit surface 30b. At this time, since the light shielding member 26 is disposed on the exit surface 30b in the vicinity of the incident surface 30a, the light P10 is absorbed by the light shielding member 26. This prevents the luminance of the exit surface 30b near the entrance surface 30a from becoming higher than the brightness of the exit surface 30b other than the vicinity of the entrance surface 30a.
　図７は本実施形態の照明装置２０の比較例であって導光板３０の入射面３０ａ近傍を拡大して入射面３０ａに垂直な断面図を示している。比較例では本実施形態から反射部材６０を省いている。光源２１から出射された光の一部Ｐ４、Ｐ５は入射面３０ａの方向には向かわずにそれぞれ低屈折率層３６及び集光部３７の方向に向かう。この時、反射部材６０が設けられていないため、光源２１から出射された光の一部Ｐ４、Ｐ５はそれぞれ側端面３６ａ、３７ａから低屈折率層３６及び集光部３７に直接入射する。 FIG. 7 is a comparative example of the illumination device 20 of the present embodiment, and shows a cross-sectional view in which the vicinity of the incident surface 30a of the light guide plate 30 is enlarged and perpendicular to the incident surface 30a. In the comparative example, the reflecting member 60 is omitted from this embodiment. Part of the light P4 and P5 emitted from the light source 21 does not go in the direction of the incident surface 30a, but goes in the direction of the low refractive index layer 36 and the condensing part 37, respectively. At this time, since the reflecting member 60 is not provided, part of the light P4 and P5 emitted from the light source 21 is directly incident on the low refractive index layer 36 and the condensing unit 37 from the side end faces 36a and 37a, respectively.
　光源２１から低屈折率層３６に直接入射した光Ｐ４は低屈折率層３６を透過し、入射面３０ａ近傍の集光部３７に入射する。低屈折率層３６から集光部３７に入射した光Ｐ４及び集光部３７に直接入射した光Ｐ５は入射面３０ａ近傍のプリズム３８の傾斜面３８ｂに入射する。傾斜面３８ｂに臨界角φ３よりも大きい入射角で入射した光は出射面３０ｂの方向に全反射する。傾斜面３８ｂに臨界角φ３よりも小さい入射角で入射した光は集光部３７から屈折して出射され、垂直面３８ａから集光部３７に屈折して再度入射する。これにより、集光部３７に対して出射と入射を繰り返すと、光が屈折して傾斜面３８ｂの入射角が徐々に大きくなるため傾斜面３８ｂで全反射する。入射面３０ａ近傍の傾斜面３８ｂで全反射した光Ｐ６、Ｐ７は入射面３０ａ近傍の出射面３０ｂから出射される。 The light P4 that is directly incident on the low refractive index layer 36 from the light source 21 is transmitted through the low refractive index layer 36 and is incident on the light collecting portion 37 in the vicinity of the incident surface 30a. The light P4 incident on the condensing unit 37 from the low refractive index layer 36 and the light P5 directly incident on the condensing unit 37 are incident on the inclined surface 38b of the prism 38 near the incident surface 30a. Light incident on the inclined surface 38b at an incident angle larger than the critical angle φ3 is totally reflected in the direction of the exit surface 30b. Light incident on the inclined surface 38b at an incident angle smaller than the critical angle φ3 is refracted and emitted from the light collecting portion 37, and refracted from the vertical surface 38a and incident again. As a result, when emission and incidence are repeated with respect to the condensing unit 37, the light is refracted and the incident angle of the inclined surface 38b gradually increases, so that the light is totally reflected by the inclined surface 38b. Lights P6 and P7 totally reflected by the inclined surface 38b near the incident surface 30a are emitted from the emission surface 30b near the incident surface 30a.
　この時、光Ｐ７は遮光部材２６によって吸収され、光Ｐ６は遮光部材２６に吸収されずに遮光部材２６の内周近傍の出射面３０ｂから出射される。このため、光Ｐ６、Ｐ７は導光板３０内を入射面３０ａから離れる方向（Ｙ方向）に導光しない。従って、反射部材６０を有しない比較例の導光板３０では本実施形態の導光板３０に比して出射面３０ｂ全体の輝度を向上することができない。 At this time, the light P7 is absorbed by the light shielding member 26, and the light P6 is not absorbed by the light shielding member 26 but is emitted from the emission surface 30b in the vicinity of the inner periphery of the light shielding member 26. For this reason, the lights P6 and P7 do not guide the light guide plate 30 in the direction away from the incident surface 30a (Y direction). Therefore, the light guide plate 30 of the comparative example that does not include the reflecting member 60 cannot improve the luminance of the entire emission surface 30b as compared with the light guide plate 30 of the present embodiment.
　また、比較例の導光板３０では光Ｐ６のように遮光部材２６の内周近傍の出射面３０ｂから出射される光が本実施形態の導光板３０よりも多くなる。そのため、出射面３０ｂから出射される照明光の輝度ムラが生じる。この時、遮光部材２６の内周近傍の出射面３０ｂは表示領域Ａ（図２参照）の周部に対向しているので、表示装置１の表示品位が低下する。 In the light guide plate 30 of the comparative example, more light is emitted from the light exit surface 30b near the inner periphery of the light shielding member 26 as in the light P6 than in the light guide plate 30 of the present embodiment. For this reason, luminance unevenness of the illumination light emitted from the emission surface 30b occurs. At this time, since the emission surface 30b in the vicinity of the inner periphery of the light shielding member 26 faces the peripheral portion of the display area A (see FIG. 2), the display quality of the display device 1 is degraded.
　これに対し、反射部材６０を有する本実施形態によれば、光源２１から出射された光は低屈折率層３６及び集光部３７に直接入射することなく、入射面３０ａから導光板３０内に入射する。従って、光源２１から低屈折率層３６及び集光部３７に直接入射した後に集光部３７で反射して入射面３０ａ近傍の出射面３０ｂから出射される光Ｐ６、Ｐ７を少なくすることができる。その結果、導光板３０内を入射面３０ａから離れる方向に導光する光を多くすることができ、出射面３０ｂ全体の輝度を向上させることができる。また、出射面３０ｂから出射される照明光の輝度ムラを低減することもできるとともに表示装置１の表示品位を向上させることができる。 On the other hand, according to the present embodiment having the reflecting member 60, the light emitted from the light source 21 does not directly enter the low refractive index layer 36 and the light condensing unit 37, and enters the light guide plate 30 from the incident surface 30a. Incident. Therefore, light P6 and P7 that are directly incident on the low refractive index layer 36 and the condensing unit 37 from the light source 21 and then reflected by the condensing unit 37 and emitted from the exit surface 30b near the entrance surface 30a can be reduced. . As a result, the amount of light guided in the direction away from the incident surface 30a in the light guide plate 30 can be increased, and the luminance of the entire emission surface 30b can be improved. In addition, the luminance unevenness of the illumination light emitted from the emission surface 30b can be reduced, and the display quality of the display device 1 can be improved.
　ここで、反射部材６０の効果を調べる実験を行った。低屈折率層３６の厚さ（Ｚ方向の厚さ）と集光部３７の厚さ（Ｚ方向の厚さ）との合計を０．０８ｍｍに設定し、反射部材６０の厚さ（Ｚ方向の厚さ）を０．１ｍｍに設定した。そして、入射面３０ａ近傍の出射面３０ｂの輝度Ｘ１及び出射面３０ｂの中央部の輝度Ｘ２を測定した。反射部材６０を有しない比較例の照明装置についても同様に輝度Ｘ１、Ｘ２を測定した。その結果、本実施形態では比較例に比して、輝度比（Ｘ１／Ｘ２）を１７ポイント程度低減することができた。この結果から、反射部材６０により入射面３０ａ近傍の出射面３０ｂの輝度上昇を抑えて出射面３０ｂから出射される照明光の輝度ムラを低減できることが判明した。 Here, an experiment for examining the effect of the reflecting member 60 was performed. The sum of the thickness of the low refractive index layer 36 (thickness in the Z direction) and the thickness of the light collecting portion 37 (thickness in the Z direction) is set to 0.08 mm, and the thickness of the reflecting member 60 (Z direction). ) Was set to 0.1 mm. And the brightness | luminance X1 of the output surface 30b of the entrance surface 30a vicinity and the brightness | luminance X2 of the center part of the output surface 30b were measured. Similarly, the luminances X1 and X2 were measured for the illumination device of the comparative example that did not have the reflecting member 60. As a result, in this embodiment, the luminance ratio (X1 / X2) could be reduced by about 17 points as compared with the comparative example. From this result, it has been found that the luminance unevenness of the illumination light emitted from the exit surface 30b can be reduced by suppressing the increase in the brightness of the exit surface 30b near the entrance surface 30a by the reflecting member 60.
　本実施形態によると、導光板３０が、入射面３０ａ及び出射面３０ｂを有するとともに第１傾斜面３３ｂを含む第１プリズム３３を光源２１の光軸方向に並設した導光部３５と、導光部３５の背面に隣接して導光部３５よりも屈折率の小さい低屈折率層３６と、低屈折率層３６に対して出射面３０ｂと反対側の面に形成されるとともに第２傾斜面３８ｂを含む第２プリズム３８を光源２１の光軸方向に並設した集光部３７とを有している。 According to this embodiment, the light guide plate 30 includes the light guide portion 35 in which the first prism 33 including the incident surface 30 a and the emission surface 30 b and including the first inclined surface 33 b is arranged in parallel in the optical axis direction of the light source 21. A low refractive index layer 36 having a refractive index smaller than that of the light guide portion 35 adjacent to the back surface of the light portion 35, and a second inclined surface formed on a surface opposite to the emission surface 30b with respect to the low refractive index layer 36. It has the condensing part 37 which arranged the 2nd prism 38 including the surface 38b in the optical axis direction of the light source 21 side by side.
　これにより、出射面３０ｂから出射された光の指向角をプリズム３３、３８の稜線に直交する方向（Ｙ方向）に絞り込むことができる。従って、出射面３０ｂにプリズムシート等を設ける必要がなく、部品点数及び製造工数を削減できる。その結果、照明装置２０の製造コストを削減できる。 Thereby, the directivity angle of the light emitted from the emission surface 30b can be narrowed down to the direction (Y direction) orthogonal to the ridgelines of the prisms 33 and 38. Therefore, it is not necessary to provide a prism sheet or the like on the emission surface 30b, and the number of parts and the number of manufacturing steps can be reduced. As a result, the manufacturing cost of the lighting device 20 can be reduced.
　また、低屈折率層３６及び集光部３７の光源２１側の側端面３６ａ、３７ａに接して配されるとともに光源２１の出射光を反射して入射面３０ａに導く反射部材６０（第１光反射部）を設けている。これにより、光源２１から出射された光は低屈折率層３６及び集光部３７に直接入射することなく、入射面３０ａから導光板３０内に入射する。従って、光源２１の出射光が低屈折率層３６及び集光部３７に直接入射した後に集光部３７で反射して入射面３０ａ近傍の出射面３０ｂから出射されることを低減できる。その結果、導光板３０内を入射面３０ａから離れる方向に導光する光を多くすることができ、出射面３０ｂ全体の輝度を向上させることができる。 In addition, the reflecting member 60 (first light) is arranged in contact with the side surface 36a, 37a on the light source 21 side of the low refractive index layer 36 and the condensing part 37 and reflects the emitted light of the light source 21 to guide the incident surface 30a. (Reflection part) is provided. As a result, the light emitted from the light source 21 enters the light guide plate 30 from the incident surface 30a without directly entering the low refractive index layer 36 and the condensing unit 37. Accordingly, it is possible to reduce the emission light of the light source 21 from being directly incident on the low refractive index layer 36 and the light converging part 37 and then being reflected by the light converging part 37 and being emitted from the light emitting surface 30b in the vicinity of the incident surface 30a. As a result, the amount of light guided in the direction away from the incident surface 30a in the light guide plate 30 can be increased, and the luminance of the entire emission surface 30b can be improved.
　また、白色顔料または銀色顔料を含有した粘着テープ状部材により反射部材６０を容易に実現できる。ここで、反射部材６０を有さない場合（図７参照）、例えば照明装置２０への衝撃により光源２１の配置位置が反射部材２４側にずれると、光源２１から低屈折率層３６及び集光部３７に直接入射する光がより多くなる。本実施形態では、反射部材６０が低屈折率層３６及び集光部３７の光源２１側の側端面３６ａ、３７ａに接して配されているので、例えば照明装置２０への衝撃により光源２１の配置位置が反射部材２４側にずれた場合でも光源２１の出射光が低屈折率層３６及び集光部３７に直接入射することを防止できる。 Moreover, the reflective member 60 can be easily realized by an adhesive tape-like member containing a white pigment or a silver pigment. Here, when the reflection member 60 is not provided (see FIG. 7), for example, when the arrangement position of the light source 21 is shifted toward the reflection member 24 due to an impact on the illumination device 20, the low refractive index layer 36 and the light collection are emitted from the light source 21. More light is incident directly on the portion 37. In the present embodiment, since the reflecting member 60 is disposed in contact with the low refractive index layer 36 and the side end surfaces 36a, 37a on the light source 21 side of the light condensing unit 37, the arrangement of the light source 21 due to an impact on the illumination device 20, for example. Even when the position is shifted to the reflecting member 24 side, it is possible to prevent the light emitted from the light source 21 from directly entering the low refractive index layer 36 and the light condensing unit 37.
　次に、本発明の第２実施形態について説明する。図８は本実施形態の照明装置２０の導光板３０の入射面３０ａ近傍を拡大して入射面３０ａに垂直な断面図を示している。説明の便宜上、前述の図１～図６に示す第１実施形態と同様の部分には同一の符号を付している。本実施形態は筐体２５の構成を変更して反射部材６０を省いている点で第１実施形態と異なっている。その他の部分は第１実施形態と同様である。 Next, a second embodiment of the present invention will be described. FIG. 8 shows a cross-sectional view perpendicular to the incident surface 30a by enlarging the vicinity of the incident surface 30a of the light guide plate 30 of the lighting device 20 of the present embodiment. For convenience of explanation, the same parts as those in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals. This embodiment is different from the first embodiment in that the configuration of the housing 25 is changed and the reflection member 60 is omitted. Other parts are the same as those in the first embodiment.
　光源２１と反射部材２４との間には延出部２５ａ（第１光反射部）が設けられている。延出部２５ａは筐体２５（図１、図２参照）の一部により形成され、筐体２５のうち光源２１に対して導光板３０と反対側の面から導光板３０に向かって延出している。延出部２５ａは低屈折率層３６及び集光部３７の光源２１側の側端面３６ａ、３７ａに接し、白色顔料または銀色顔料を含有した樹脂成形品等により形成される。なお、金属等の基材上に白色塗料または銀色塗料を塗布して延出部２５ａを形成してもよい。 An extending portion 25a (first light reflecting portion) is provided between the light source 21 and the reflecting member 24. The extending portion 25 a is formed by a part of the housing 25 (see FIGS. 1 and 2), and extends from the surface of the housing 25 opposite to the light guide plate 30 toward the light guide plate 30 with respect to the light source 21. ing. The extending portion 25a is in contact with the side end surfaces 36a and 37a on the light source 21 side of the low refractive index layer 36 and the condensing portion 37, and is formed of a resin molded product containing a white pigment or a silver pigment. The extending portion 25a may be formed by applying a white paint or a silver paint on a base material such as metal.
　本実施形態によると、第１実施形態と同様な効果を得ることができる。また、光源２１と導光板３０とを収納する筐体２５を備え、筐体２５の一部に白色顔料または銀色顔料を含有させて延出部２５ａ（第１光反射部）を形成している。これにより、反射部材６０が不要になるため、部品点数を削減できる。従って、照明装置２０の製造コストを削減することができる。 According to this embodiment, the same effect as that of the first embodiment can be obtained. Moreover, the housing | casing 25 which accommodates the light source 21 and the light-guide plate 30 is provided, and the extending part 25a (1st light reflection part) is formed by making a white pigment or a silver pigment contain in a part of housing | casing 25. FIG. . Thereby, since the reflection member 60 becomes unnecessary, the number of parts can be reduced. Therefore, the manufacturing cost of the lighting device 20 can be reduced.
　次に、本発明の第３実施形態について説明する。図９は本実施形態の照明装置２０の導光板３０の入射面３０ａ近傍を拡大して入射面３０ａに垂直な断面図を示している。説明の便宜上、前述の図１～図６に示す第１実施形態と同様の部分には同一の符号を付している。本実施形態ではシート状の反射部材６１（第２光反射部）をさらに設けている点で第１実施形態と異なっている。また、本実施形態では光源２１と入射面３０ａとの間の距離を第１実施形態よりも長くしている。その他の部分は第１実施形態と同様である。 Next, a third embodiment of the present invention will be described. FIG. 9 shows a cross-sectional view perpendicular to the incident surface 30a by enlarging the vicinity of the incident surface 30a of the light guide plate 30 of the lighting device 20 of the present embodiment. For convenience of explanation, the same parts as those in the first embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals. This embodiment is different from the first embodiment in that a sheet-like reflecting member 61 (second light reflecting portion) is further provided. In the present embodiment, the distance between the light source 21 and the incident surface 30a is longer than that in the first embodiment. Other parts are the same as those in the first embodiment.
　反射部材６１は光源２１に対して反射部材６０と反対側に配され、光源２１の出射光の一部を反射して入射面３０ａに導く。反射部材６１は白色顔料または銀色顔料を含有したポリエステル等の粘着テープ状部材により形成され、表示パネル１０（図１、図２参照）の受光面側に貼着される。なお、反射部材６１の材質は反射部材６０と同じであってもよいし、異なってもよい。また、反射部材６１を遮光部材２６の光源２１側の側端面に接するように配置すると、光源２１の出射光をより確実に入射面３０ａに導くことができる。また、第２実施形態のように筐体２５の一部に白色顔料または銀色顔料を含有させて反射部材６１を形成してもよい。 The reflection member 61 is disposed on the opposite side of the reflection member 60 with respect to the light source 21, and reflects part of the emitted light from the light source 21 to guide it to the incident surface 30a. The reflection member 61 is formed of an adhesive tape-like member such as polyester containing a white pigment or a silver pigment, and is attached to the light receiving surface side of the display panel 10 (see FIGS. 1 and 2). Note that the material of the reflecting member 61 may be the same as or different from that of the reflecting member 60. Further, if the reflecting member 61 is disposed so as to be in contact with the side end surface of the light shielding member 26 on the light source 21 side, the emitted light of the light source 21 can be more reliably guided to the incident surface 30a. Further, as in the second embodiment, the reflecting member 61 may be formed by containing a white pigment or a silver pigment in a part of the housing 25.
　反射部材６０が低屈折率層３６及び集光部３７に接して配されているため、光源２１から出射された光の一部Ｐ２１は反射部材６０に入射し、低屈折率層３６及び集光部３７には直接入射しない。反射部材６０で反射した光Ｐ２２は入射面３０ａから導光部３５に入射する。そして、導光部３５内に入射した光Ｐ２３は入射面３０ａから離れる方向に導光して入射面３０ａ近傍以外の出射面３０ｂから出射される。従って、出射面３０ｂ全体の輝度を向上させることができる。 Since the reflecting member 60 is disposed in contact with the low refractive index layer 36 and the light collecting portion 37, a part P21 of the light emitted from the light source 21 enters the reflecting member 60, and the low refractive index layer 36 and the light collecting light are collected. It does not enter the part 37 directly. The light P22 reflected by the reflecting member 60 enters the light guide 35 from the incident surface 30a. The light P23 that has entered the light guide 35 is guided in a direction away from the incident surface 30a and is emitted from the exit surface 30b other than the vicinity of the incident surface 30a. Accordingly, it is possible to improve the luminance of the entire emission surface 30b.
　また、光源２１から出射された光の一部Ｐ３１は反射部材６１に入射する。反射部材６１で反射した光Ｐ３２は入射面３０ａから導光部３５に入射する。そして、導光部３５内に入射した光Ｐ３３は入射面３０ａから離れる方向（Ｙ方向）に導光して入射面３０ａ近傍以外の出射面３０ｂから出射される。これにより、光源２１と入射面３０ａとの間の距離を第１実施形態よりも長くしても光源２１の出射光を入射面３０ａに確実に導くことができる。従って、出射面３０ｂ全体の輝度を向上させることができる。 Further, a part P 31 of the light emitted from the light source 21 enters the reflecting member 61. The light P32 reflected by the reflecting member 61 enters the light guide 35 from the incident surface 30a. The light P33 incident on the light guide 35 is guided in a direction away from the incident surface 30a (Y direction) and emitted from the emission surface 30b other than the vicinity of the incident surface 30a. Thereby, even if the distance between the light source 21 and the incident surface 30a is made longer than that in the first embodiment, the emitted light from the light source 21 can be reliably guided to the incident surface 30a. Accordingly, it is possible to improve the luminance of the entire emission surface 30b.
　また、第１実施形態よりも光源２１と入射面３０ａとの間の距離を長くしているため、光源２１の発熱による導光板３０の変形や破損を防止できる。このため、発熱量が大きいトップビュータイプのＬＥＤや冷陰極蛍光ランプ（ＣＣＦＬ：Ｃｏｌｄ　Ｃａｔｈｏｄｅ　Ｆｌｕｏｒｅｓｃｅｎｔ　Ｌａｍｐ）を光源２１に使用することができる。従って、照明装置２０の設計の自由度を向上させることができる。 In addition, since the distance between the light source 21 and the incident surface 30a is longer than that in the first embodiment, the light guide plate 30 can be prevented from being deformed or damaged due to heat generated by the light source 21. For this reason, a top view type LED or a cold cathode fluorescent lamp (CCFL: Cold Cathode Fluorescent Lamp) having a large calorific value can be used as the light source 21. Therefore, the freedom degree of design of the illuminating device 20 can be improved.
　本実施形態によると、第１実施形態と同様な効果を得ることができる。また、光源２１に対して反射部材６０（第１光反射部）と反対側に配されて光源２１の出射光を反射して入射面３０ａに導く反射部材６１（第２光反射部）をさらに備えているので、光源２１と入射面３０ａとの間の距離を第１実施形態よりも長くすることができる。これにより、光源２１の発熱による導光板３０の変形や破損を防止することができる。 According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, a reflection member 61 (second light reflection portion) that is disposed on the opposite side of the light source 21 from the reflection member 60 (first light reflection portion) and reflects the light emitted from the light source 21 and guides it to the incident surface 30a. Since it is provided, the distance between the light source 21 and the incident surface 30a can be made longer than in the first embodiment. Thereby, the light guide plate 30 can be prevented from being deformed or damaged due to heat generated by the light source 21.
　第１～第３実施形態において、プリズム３３を導光部３５と低屈折率層３６との界面に設けてもよい。また、プリズム３２を導光板３０の出射面３０ｂに突設してもよい。 In the first to third embodiments, the prism 33 may be provided at the interface between the light guide 35 and the low refractive index layer 36. Further, the prism 32 may be provided so as to protrude from the light exit surface 30 b of the light guide plate 30.
　また、光源２１として出射範囲の広い冷陰極蛍光ランプ等の線状光源を用いてもよい。この場合でも第１～第３実施形態と同様な効果を得ることができる。 Further, a linear light source such as a cold cathode fluorescent lamp having a wide emission range may be used as the light source 21. Even in this case, the same effects as those of the first to third embodiments can be obtained.
　また、反射部材６０、６１に含有させる顔料の色は光反射率の高い明色であればよく、例えば黄色顔料等を用いてもよい。 Further, the color of the pigment contained in the reflecting members 60 and 61 may be a light color having a high light reflectance, and for example, a yellow pigment or the like may be used.
　また、照明装置２０を屋内や屋外を照明する照明器具として用いてもよい。 Moreover, you may use the illuminating device 20 as a lighting fixture which illuminates indoor or the outdoors.
　本発明によると、導光板を備えた照明装置や照明器具等の照明装置及び照明装置を用いた液晶表示装置等の表示装置に利用することができる。 According to the present invention, it can be used for a lighting device such as a lighting device or a lighting fixture provided with a light guide plate, and a display device such as a liquid crystal display device using the lighting device.
　　　１　　表示装置
　　１０　　表示パネル
　　１１　　アクティブマトリックス基板
　　１２　　対向基板
　　１３　　偏光フィルム
　　２０　　照明装置
　　２１　　光源
　　２４　　反射部材
　　２５　　筐体
　　２５ａ　延出部（第１光反射部）
　　２６　　遮光部材
　　３０　　導光板
　　３０ａ　入射面
　　３０ｂ　出射面
　　３２　　プリズム（第３プリズム）
　　３３　　プリズム（第１プリズム）
　　３３ａ、３８ａ　垂直面
　　３３ｂ、３８ｂ　傾斜面
　　３４　　水平面
　　３５　　導光部
　　３６　　低屈折率層
　　３６ａ　側端面
　　３７　　集光部
　　３８　　プリズム（第２プリズム）
　　３８ａ　側端面
　　６０　　反射部材（第１光反射部）
　　６１　　反射部材（第２光反射部） DESCRIPTION OF SYMBOLS 1 Display apparatus 10 Display panel 11 Active matrix board | substrate 12 Opposite board | substrate 13 Polarizing film 20 Illuminating device 21 Light source 24 Reflective member 25 Case 25a Extension part (1st light reflection part)
26 light shielding member 30 light guide plate 30a entrance surface 30b exit surface 32 prism (third prism)
33 Prism (first prism)
33a, 38a Vertical surface 33b, 38b Inclined surface 34 Horizontal surface 35 Light guide portion 36 Low refractive index layer 36a Side end surface 37 Condensing portion 38 Prism (second prism)
38a Side end surface 60 Reflecting member (first light reflecting portion)
61 Reflective member (second light reflector)

Claims (5)

  1. 　光源と、前記光源に対向する入射面を側端面に有するとともに前記入射面から入射した光を導光して前面に配される出射面から照明光を出射する導光板とを備えた照明装置において、
    　前記導光板が、前記入射面及び前記出射面を有するとともに第１傾斜面を含む第１プリズムを前記光源の光軸方向に並設した導光部と、前記導光部の背面に隣接して前記導光部よりも屈折率の小さい低屈折率層と、前記低屈折率層に対して前記出射面と反対側の面に形成されるとともに第２傾斜面を含む第２プリズムを前記光軸方向に並設した集光部とを有し、
    　前記低屈折率層及び前記集光部の前記光源側の側端面に接して配されるとともに前記光源の出射光を反射して前記入射面に導く第１光反射部を設けたことを特徴とする照明装置。     In an illuminating device comprising: a light source; and a light guide plate that has an incident surface facing the light source on a side end surface, guides light incident from the incident surface, and emits illumination light from an exit surface disposed on a front surface. ,
    The light guide plate has the entrance surface and the exit surface and a first prism including a first inclined surface arranged in parallel in the optical axis direction of the light source, and adjacent to the back surface of the light guide portion A low-refractive index layer having a refractive index smaller than that of the light guide, and a second prism formed on a surface opposite to the exit surface with respect to the low-refractive index layer and including a second inclined surface; And a light collecting portion arranged in parallel in the direction,
    A first light reflecting portion is provided that is disposed in contact with the light source side side end surface of the low refractive index layer and the condensing portion, and reflects the emitted light of the light source to guide it to the incident surface. Lighting device.
  2. 　前記光源と前記導光板とを収納する筐体を備え、前記筐体に白色顔料または銀色顔料を含有させることにより第１光反射部を形成したことを特徴とする請求項１に記載の照明装置。 2. The lighting device according to claim 1, further comprising a housing that houses the light source and the light guide plate, wherein the first light reflecting portion is formed by containing a white pigment or a silver pigment in the housing. .
  3. 　白色顔料または銀色顔料を含有した粘着テープ状部材により第１光反射部を形成したことを特徴とする請求項１に記載の照明装置。 The lighting device according to claim 1, wherein the first light reflecting portion is formed of an adhesive tape-like member containing a white pigment or a silver pigment.
  4. 　前記光源に対して第１光反射部と反対側に配されて前記光源の出射光を反射して前記入射面に導く第２光反射部をさらに備えたことを特徴とする請求項１～請求項３のいずれかに記載の照明装置。 The second light reflecting portion, further provided on the opposite side of the first light reflecting portion with respect to the light source, for reflecting light emitted from the light source and guiding it to the incident surface. Item 4. The lighting device according to any one of Items 3 to 4.
  5. 　請求項１～請求項４のいずれかに記載の照明装置と、前記導光板の前記出射面に対向して配置される表示パネルとを備えたことを特徴とする表示装置。 A display device comprising: the illumination device according to any one of claims 1 to 4; and a display panel disposed to face the light emission surface of the light guide plate.
PCT/JP2013/060784 2012-04-12 2013-04-10 Illumination device and display device provided with same WO2013154124A1 (en)

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JPH10247413A (en) * 1997-03-03 1998-09-14 Omron Corp Surface light source device
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JP2008041359A (en) * 2006-08-03 2008-02-21 Mitsui Chemicals Inc Reflector and backlighting device
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Publication number Priority date Publication date Assignee Title
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CN108153059B (en) * 2018-02-01 2023-08-04 Oppo广东移动通信有限公司 Backlight module, display device and electronic equipment

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