CN108732675B - Lighting device - Google Patents

Lighting device Download PDF

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Publication number
CN108732675B
CN108732675B CN201810161055.9A CN201810161055A CN108732675B CN 108732675 B CN108732675 B CN 108732675B CN 201810161055 A CN201810161055 A CN 201810161055A CN 108732675 B CN108732675 B CN 108732675B
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China
Prior art keywords
region
light
main surface
prisms
guide plate
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CN201810161055.9A
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Chinese (zh)
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CN108732675A (en
Inventor
福间俊彦
小村真一
浅川阳一
小野田宪
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Japan Display Inc
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Japan Display Inc
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    • 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
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0031—Reflecting element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Planar Illumination Modules (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Liquid Crystal (AREA)
  • Light Guides In General And Applications Therefor (AREA)

Abstract

The lighting device according to one embodiment includes a light guide plate, a1 st light source, and a plurality of prisms. The light guide plate has a1 st main surface and a2 nd main surface opposite to the 1 st main surface and including a plurality of surfaces. The 1 st light source irradiates laser along the 1 st irradiation direction. The plurality of prisms are provided on the 2 nd main surface. The laser beam travels in the 1 st traveling direction in a plan view. The 2 nd main surface has a1 st region and a2 nd region arranged in this order along the 1 st traveling direction, and light emitted from the 1 st light source enters the 1 st region. The plurality of prisms include a plurality of 1 st prisms in the 2 nd region. In a cross-sectional view, the distance from the 1 st main surface is longer in the order of the 1 st region and the 2 nd region. The 1 st irradiation direction is inclined with respect to the 1 st main surface.

Description

Lighting device
Cross reference to related documents
This application claims priority based on japanese patent application No. 2017-082901 filed on 19/4/2017, the entire contents of which are incorporated herein by reference.
Technical Field
Embodiments of the present invention relate to a lighting device.
Background
For example, a display device such as a liquid crystal display device includes a display panel having pixels and an illumination device such as a backlight for illuminating the display panel. The illumination device includes a light source that emits light, and a light guide plate that is irradiated with the light from the light source. Light from the light source enters the light guide plate from a side surface, propagates through the light guide plate, and is emitted from an emission surface corresponding to one main surface of the light guide plate.
However, if the light source is disposed outside the side surface of the light guide plate, the entire illumination device becomes large, and it becomes difficult to make the display device compact.
Documents of the prior art
Patent document 1: japanese patent laid-open publication No. 2004-38108
Patent document 2: japanese patent laid-open publication No. 2011-238484
Disclosure of Invention
An object of one embodiment of the present disclosure is to provide a lighting device that is reduced in size.
The lighting device according to one embodiment includes a light guide plate, a1 st light source, and a plurality of prisms. The light guide plate has a1 st main surface and a2 nd main surface opposite to the 1 st main surface and including a plurality of surfaces. The 1 st light source irradiates laser along the 1 st irradiation direction. The plurality of prisms are provided on the 2 nd main surface. The laser beam travels in the 1 st traveling direction in a plan view. The 2 nd main surface has a1 st region and a2 nd region arranged in this order along the 1 st traveling direction, and light emitted from the 1 st light source enters the 1 st region. The plurality of prisms include a plurality of 1 st prisms in the 2 nd region. In a cross-sectional view, the distance from the 1 st main surface is longer in the order of the 1 st region and the 2 nd region. The 1 st irradiation direction is inclined with respect to the 1 st main surface.
Drawings
Fig. 1 is a perspective view showing a schematic configuration of a display device according to embodiment 1.
Fig. 2 is a schematic cross-sectional view of the display device according to embodiment 1.
Fig. 3 is a schematic plan view of the lighting device according to embodiment 1.
Fig. 4 is a schematic cross-sectional view of the light guide plate according to embodiment 1.
Fig. 5 is a schematic cross-sectional view of a part of the lighting device according to embodiment 1.
Fig. 6 is an enlarged cross-sectional view of the 1 st prism according to embodiment 1.
Fig. 7 is an enlarged cross-sectional view of the 2 nd prism according to embodiment 1.
Fig. 8 is a diagram showing a luminance distribution of the light guide plate according to the comparative example.
Fig. 9 is a diagram showing a luminance distribution of a light guide plate according to another comparative example.
Fig. 10 is a schematic cross-sectional view of the light guide plate according to the comparative example shown in fig. 9.
Fig. 11 is a diagram showing an example of luminance distribution of the light guide plate according to embodiment 1.
Fig. 12 is a schematic cross-sectional view of the lighting device according to embodiment 2.
Fig. 13 is a schematic cross-sectional view of the lighting device according to embodiment 3.
Fig. 14 is a schematic cross-sectional view of a part of the lighting device according to embodiment 4.
Fig. 15 is a schematic cross-sectional view of a part of the lighting device according to embodiment 5.
Fig. 16 is a schematic cross-sectional view of a part of the lighting device according to embodiment 6.
Fig. 17 is a schematic cross-sectional view of a part of the lighting device according to embodiment 7.
Fig. 18 is a schematic cross-sectional view of the lighting device according to embodiment 8.
Fig. 19 is a schematic cross-sectional view of a part of the lighting device according to embodiment 9.
Detailed Description
Some embodiments are described with reference to the accompanying drawings.
The disclosure herein is merely an example, and it is needless to say that appropriate modifications can be made by those skilled in the art while maintaining the gist of the invention, and the modifications are included in the scope of the invention. In addition, the drawings are schematically illustrated in comparison with actual forms in order to make the description more clear, but the drawings are merely illustrative and do not limit the explanation of the present invention. In the drawings, the same or similar elements arranged in series are not denoted by the same reference numerals. In the present specification and the drawings, the same reference numerals are given to constituent elements that perform the same or similar functions as those of the above-described elements in the illustrated drawings, and overlapping detailed description thereof may be omitted.
In the present specification, expressions "α includes A, B or C", "α includes either A, B or C", and "α includes one selected from the group consisting of A, B and C" do not exclude a case where a plurality of combinations of a to C are included in α unless otherwise specified. Further, these expressions do not exclude the case where α includes other elements.
In each embodiment, a transmissive liquid crystal display device is disclosed as an example of a display device. As an example of the illumination device, a backlight of a liquid crystal display device is disclosed. However, the embodiments do not prevent the technical ideas disclosed in the embodiments from being applied to other types of display devices or lighting devices. As another type of display device, for example, it is assumed that: a liquid crystal display device having a transmission-type function and a reflection-type function of reflecting external light and using the reflected light for display, a display device having a Mechanical display panel in which a Micro Electro Mechanical System (MEMS) shutter functions as an optical element, and the like. As another type of lighting device, for example, a front light or the like arranged on the front surface of the display device is assumed. Further, the illumination device may be used for a different purpose from the illumination of the display device.
[ embodiment 1 ]
Fig. 1 is a perspective view showing a schematic configuration of a display device 1 according to embodiment 1. The display device 1 can be used in various devices such as a smart phone, a tablet terminal, a mobile phone terminal, a personal computer, a television receiving device, an in-vehicle device, a game device, and a wearable terminal.
The display device 1 includes a display panel 2, an illumination device 3 serving as a backlight, a driver IC chip 4 for driving the display panel 2, and flexible circuit boards FPC1 and FPC2 for transmitting control signals to the display panel 2 and the illumination device 3. For example, the flexible circuit boards FPC1 and FPC2 are connected to a control module that controls the operations of the display panel 2 and the lighting device 3.
The display panel 2 includes a1 st substrate SUB1 (array substrate) and a2 nd substrate SUB2 (counter substrate) facing the 1 st substrate SUB 1. The display panel 2 has a display area DA for displaying an image. The display panel 2 includes, for example, a plurality of pixels PX arranged in a matrix in the display region DA.
The lighting device 3 includes a1 st light source LS1, a2 nd light source LS2, and a light guide plate LG opposed to the 1 st substrate SUB 1. The 1 st light source LS1 faces one end of the lower surface (surface not facing the 1 st substrate SUB 1) of the light guide plate LG, and the 2 nd light source LS2 faces the other end of the lower surface (surface not facing the 1 st substrate SUB 1) of the light guide plate LG. Although 1 light source LS1 and LS2 are shown in fig. 1, a plurality of 1 st light sources LSI and a plurality of 2 nd light sources LS2 are actually provided (see fig. 3).
As shown in FIG. 1, a1 st direction X, a2 nd direction Y and a3 rd direction Z are defined. The directions X, Y, Z are, for example, orthogonal to each other. In the present invention, the display device 1 is viewed in a plane from a direction parallel to the 3 rd direction Z. In addition, a cross section of the display device 1 viewed in parallel with the X-Z plane is referred to as a cross section. In the example of fig. 1, each of the substrates SUB1, SUB2 and the light guide plate LG has a long side along the 1 st direction X and a short side along the 2 nd direction Y, and has a rectangular shape in plan view. However, the shapes of the substrates SUB1 and SUB2 and the light guide plate LG are not limited to this, and may be other shapes such as a square or a circle in a plan view.
Fig. 2 is a diagrammatic cross-sectional view of the display device 1 parallel to the X-Z plane. The display panel 2 further includes a seal SL and a liquid crystal layer LC. The substrates SUB1 and SUB2 are bonded together by the seal SL. The liquid crystal layer LC is sealed between the seal SL and the substrates SUB1 and SUB 2.
A1 st polarizing plate PL1 is attached to the lower surface (surface facing the light guide plate LG) of the 1 st substrate SUB 1. A2 nd polarizing plate PL2 is attached to the upper surface (surface not facing the 1 st substrate SUB 1) of the 2 nd substrate SUB 2. The polarizing axes of the polarizing plates PL1 and PL2 are orthogonal to each other.
The light guide plate LG includes a1 st main surface 51 opposed to the display panel 2, a2 nd main surface 52 opposite to the 1 st main surface 51, a1 st side surface 53, and a2 nd side surface 54 opposite to the 1 st side surface 53. The 1 st light source LSI faces the 1 st side surface 53 side end of the 2 nd main surface 52, and the 2 nd light source LS2 faces the 2 nd side surface 54 side end of the 2 nd main surface 52. Optical elements such as lenses may be further disposed between the 1 st light source LS1 and the end portion of the 2 nd main surface 52 on the 1 st side surface 53 side and between the 2 nd light source LS2 and the end portion of the 2 nd main surface 52 on the 2 nd side surface 54 side, and the width and angle of light from the light sources LS1 and LS2 may be adjusted.
The 1 st light source LS1 irradiates diffused light having diffusion centered in the 1 st irradiation direction DL1 to the vicinity of the 1 st side surface 53 side end of the 2 nd main surface 52. The 2 nd light source LS2 irradiates diffused light having diffusion centered in the 2 nd irradiation direction DL2 to the vicinity of the end portion of the 2 nd main surface 52 on the 2 nd side surface 54 side. The irradiation directions DL1 and DL2 are, for example, opposite directions in the 1 st direction X, and are each inclined in the 3 rd direction Z with respect to the 1 st main surface 51. That is, in the present embodiment, the 1 st irradiation direction DL1 does not coincide with the 1 st direction X in cross section. However, the 1 st irradiation direction DL1 coincides with the 1 st direction X in plan view. For example, a laser light source such as a semiconductor laser that emits polarized laser light may be used as the light emitting element of each of the light sources LS1 and LS 2.
Each of the light sources LS1 and LS2 may include a plurality of light-emitting elements that emit light of different colors. For example, if each of the light sources LS1 and LS2 includes 3 light-emitting elements that emit red, green, and blue light, light of a mixed color (for example, white) of these colors can be obtained.
The display device 1 includes a prism sheet PS between the display panel 2 and the light guide plate LG. Further, the display device 1 includes a diffusion sheet DS (diffusion layer) between the prism sheet PS and the display panel 2. For example, the prism sheet PS includes a plurality of prisms extending parallel to the 2 nd direction Y. These prisms are formed on, for example, the lower surface (surface facing the light guide plate LG) of the prism sheet PS. However, these prisms may be formed on the upper surface (the surface facing the display panel 2) of the prism sheet PS.
In fig. 2, an example of the optical path of the light emitted from the 1 st light source LS1 is shown by a broken line, and an example of the optical path of the light emitted from the 2 nd light source LS2 is shown by a one-dot chain line. The light emitted from the 1 st light source LS1 enters the light guide plate LG from the 1 st side surface 53 side end of the 2 nd main surface 52, propagates through the light guide plate LG while being reflected by the main surfaces 51 and 52, and finally exits from the 1 st main surface 51 out of the total reflection condition of the 1 st main surface 51. The light emitted from the 2 nd light source LS2 enters the light guide plate LG from the end portion on the 2 nd side surface 54 side of the 2 nd main surface 52, propagates through the light guide plate LG while being reflected on the main surfaces 51 and 52, and finally exits from the 1 st main surface 51 out of the total reflection condition of the 1 st main surface 51. Thus, the 1 st main surface 51 corresponds to an emission surface from which light is emitted. In such a configuration, since the irradiation directions DL1 and DL2 are inclined with respect to the first main surface 51, the light emitted from the laser light sources LS1 and LS2 can be prevented from being directly emitted from the side surfaces 54 and 53 without being reflected by the main surfaces 51 and 52. That is, since the laser light is less likely to transmit from the vicinity of the 1 st side surface 53 or the 2 nd side surface 54 to the outside, the use efficiency of the laser light is improved.
The prism sheet PS converts light emitted from the 1 st main surface 51 into light substantially parallel to the 3 rd direction Z. Here, the "light substantially parallel to the 3 rd direction Z" includes not only light strictly parallel to the 3 rd direction Z but also light whose inclination with respect to the 3 rd direction Z is sufficiently smaller by the prism sheet PS than when the light is emitted from the 1 st main surface 51. From the viewpoint of maintaining the polarization of the light from each of the light sources LS1, LS2, it is preferable that the prisms of the prism sheet PS are formed on the lower surface. The light having passed through the prism sheet PS is diffused by the diffusion sheet DS and irradiated on the display panel 2. Even when the angle of view of the light passing through the prism sheet PS is narrow, the angle of view can be enlarged by diffusing the light with the diffusion sheet DS.
When the light from the light sources LS1 and LS2 reaches the display panel 2 in a sufficiently polarized state, the 1 st polarizing plate PL1 may be omitted. When the 1 st polarizing plate PL1 is omitted, for example, the light transmittances of the substrates SUB1 and SUB2 are increased, whereby a so-called transparent liquid crystal display device in which the background of the display device 1 is visible can be obtained.
Fig. 3 is a schematic plan view of the lighting device 3. In the example of the figure, 81 st light sources LS1 are arranged along the end portion (a 1 in fig. 3) on the 1 st side surface 53 side of the light guide plate LG, and 82 nd light sources LS2 are arranged along the end portion (a 5 in fig. 3) on the 2 nd side surface 54 side of the light guide plate LG. The intensity of light emitted from the 1 st light source LS1 is highest in the 1 st optical axis AX1 ', and the intensity of light emitted from the 2 nd light source LS2 is highest in the 2 nd optical axis AX 2'. The light sources LS1 and LS2 overlap both ends of the light guide plate LG in the thickness direction (3 rd direction Z) of the light guide plate LG. In the example of fig. 2, all of the light sources LS1 and LS2 overlap the light guide plate LG, but a part of the light sources LS1 and LS2 may overlap the light guide plate LG.
As shown in the drawing, the light sources LS1 and LS2 are arranged in a shifted manner in the 2 nd direction Y. That is, the 1 st optical axis AX1 'of light emitted from the 1 st light source LS1 in the 1 st traveling direction DL 1' (the 1 st irradiation direction DL1 in plan view) and the 2 nd optical axis AX2 'of light emitted from the 2 nd light source LS2 in the 2 nd traveling direction DL 2' (the 2 nd irradiation direction DL2 in plan view) are shifted from each other in the 2 nd direction Y. In addition, the 1 st optical axis AX1 'and the 2 nd optical axis AX 2' may coincide (align) in the 2 nd direction Y.
Fig. 4 is a schematic cross-sectional view of the light guide plate LG parallel to the X-Z plane. The 1 st main surface 51 of the light guide plate LG is a plane parallel to the 1 st direction X and the 2 nd direction Y. The 2 nd major face 52 includes a plurality of faces having a1 st region a1, a2 nd region a2, A3 rd region A3, a4 th region a4, and a5 th region a 5. As shown in the plan view of fig. 3, the 1 st region a1 is provided on the end portion on the 1 st side surface 53 side from one end to the other end in the 2 nd direction Y of the light guide plate LG. The 1 st region a1 is a light incident surface on which light emitted from the 1 st light source LS1 is incident with respect to the light guide plate LG. The 5 th region a5 is provided at the end on the 2 nd side surface 54 side from one end to the other end of the light guide plate LG in the 2 nd direction Y. The 5 th region a5 is a light incident surface on which light emitted from the 2 nd light source LS2 is incident with respect to the light guide plate LG. The 2 nd, 3 rd, and 4 th regions a2, A3, and a4 are provided between the 1 st region a1 and the 5 th region a5 from one end to the other end of the light guide plate LG in the 2 nd direction Y.
The 1 st region a1, the 2 nd region a2, the 3 rd region A3, the 4 th region a4, and the 5 th region a5 are arranged in this order along the 1 st traveling direction DL 1'. For example, in the 1 st direction X, the width of the 1 st region a1 is equal to the width of the 5 th region a5, and the width of the 2 nd region a2 is equal to the width of the 4 th region a 4. In the 1 st direction X, the width of the 3 rd region A3 is smaller than the width of each of the regions a2 and a 5. However, the widths of the regions a2, a4, a1, and a5 may be different from each other, and the width of the 3 rd region A3 may be equal to or greater than the widths of the regions a2 and a 4.
As shown in fig. 4, the 1 st, 2 nd, 4 th, and 5 th regions a1, a2, a4, and a5 are inclined with respect to the 1 st main surface 51. The 3 rd region a3 is parallel to the 1 st major surface 51. The term "parallel" used herein includes the case where the 3 rd region A3 is inclined with respect to the 1 st main surface 51 at an angle sufficiently smaller than the angle at which each of the regions a1, a2, a4, and a5 is inclined with respect to the 1 st main surface 51 (the case where the regions are substantially (substantially) parallel to the 1 st main surface 51).
A plurality of prisms P are provided on the 2 nd main surface 52. The plurality of prisms P includes a plurality of 1 st prisms P1 in the 2 nd region a2, a plurality of 2 nd prisms P2 in the 3 rd region A3, and a plurality of 3 rd prisms P3 in the 4 th region a 4. The prisms P1, P2, and P3 extend in the 2 nd direction Y. The sectional shape of the 1 st prism P1 is the same in the 2 nd direction Y, for example, but may be different. The same applies to the 2 nd prism P2 and the 3 rd prism P3.
For example, the 1 st prism P1 and the 2 nd prism P2 are different in shape from each other. Further, the 3 rd prism P3 and the 2 nd prism P2 are also different in shape from each other. The 1 st prism P1 and the 3 rd prism P3 may have the same shape (including a symmetrical shape).
For example, the 1 st prisms P1 and the 2 nd prisms P2 are arranged at different densities. Further, the 3 rd prisms P3 and the 2 nd prisms P2 are also arranged at different densities. The 1 st prisms P1 and the 3 rd prisms P3 may be arranged at the same density.
In the cross section, a line segment connecting the apexes of the 1 st prisms P1 is referred to as a1 st virtual line VL1, a line segment connecting the apexes of the 2 nd prisms P2 is referred to as a2 nd virtual line VL2, and a line segment connecting the apexes of the 3 rd prisms P3 is referred to as a3 rd virtual line VL 3. In the example of fig. 4, each of the virtual lines VL1, VL2, and VL3 is a straight line. However, the virtual lines VL1, VL2, and VL3 may be curved at least partially or may be curved.
The 1 st region a1 is inclined at a1 st angle θ 1 with respect to the 1 st major surface 51. The 1 st imaginary line VL1 is inclined at the 2 nd angle θ 2 with respect to the 1 st main surface 51. The 3 rd imaginary line VL3 is inclined at a4 th angle θ 4 with respect to the 1 st major surface 51. The 5 th region a5 is inclined at a5 th angle θ 5 with respect to the 1 st major surface 51. Each of the angles θ 1, θ 2, θ 4, and θ 5 is an acute angle. For example, the 1 st angle θ 1 is substantially (substantially) equal to the 5 th angle θ 5 (θ 1 ≈ θ 5), and the 2 nd angle θ 2 is substantially (substantially) equal to the 4 th angle θ 4 (θ 2 ≈ θ 4). For example, each angle θ 1, θ 5 is larger than each angle θ 2, θ 4 (θ 1 ≈ θ 5> θ 2 ≈ θ 4). However, the 1 st angle θ 1 and the 5 th angle θ 5 may be different from the 2 nd angle θ 2 and the 4 th angle θ 4 (θ 1 ≠ θ 5, θ 2 ≠ θ 4).
The 2 nd virtual line VL2 is inclined with respect to each of the virtual lines VL1, VL 3. The 3 rd angle θ 3 formed by the 2 nd virtual line VL2 and the 1 st main surface 51 is smaller than the respective angles θ 1, θ 2, θ 4, and θ 5 (θ 3< θ 1, θ 2, θ 4, and θ 5). In the example of fig. 4, the 2 nd imaginary line VL2 is parallel to the 1 st main surface 51. The term "parallel" as used herein includes not only the case where the 2 nd angle θ 2 is zero but also the case where the angle is sufficiently smaller than each of the angles θ 1, θ 2, θ 4, and θ 5 (the case where the angle is substantially (substantially) parallel to the 1 st main surface 51).
Here, the thickness of the light guide plate LG in the 1 st region a1 (the distance between the 1 st region a1 and the 1 st main surface 51) is defined as D1, the thickness of the light guide plate LG in the 2 nd region a2 (the distance between the 2 nd region a2 and the 1 st main surface 51) is defined as D2, the thickness of the light guide plate LG in the 3 rd region A3 (the distance between the 3 rd region A3 and the 1 st main surface 51) is defined as D3, the thickness of the light guide plate LG in the 4 th region a4 (the distance between the 4 th region a4 and the 1 st main surface 51) is defined as D4, and the thickness of the light guide plate LG in the 5 th region a5 (the distance between the 5 th region a5 and the 1 st main surface) is defined as D5. The distance D1 increases from the 1 st side surface 53 toward the boundary between the regions a1 and a 2. The distance D2 increases from the boundary between the regions a1 and a2 to the boundary between the regions a2 and A3. The distance D5 increases from the 2 nd side surface 54 toward the boundary between the regions a4 and a 5. The distance D4 increases from the boundary between the regions a4 and a5 to the boundary between the regions A3 and a 4. In the example of fig. 4, the distance D3 is constant.
In such a shape, the distance D3 is longer than the distance D1 at any position of the 1 st region a1 (D3> D1), and longer than the distance D2 at any position of the 2 nd region a2 (D3> D2). Further, the distance D3 is longer than the distance D5 at any position of the 5 th region a5 (D3> D5), and longer than the distance D4 at any position of the 4 th region a4 (D3> D4).
Fig. 5 is a cross-sectional view showing an enlarged periphery of the 1 st region a1 of the lighting device 3. Fig. 5 illustrates a relationship between the inclination angle of the light emitted from the 1 st light source LS1 and the inclination angle θ 1 of the 1 st region a1 of the light guide plate LG. In fig. 5, the 1 st prism P1 of the light guide plate LG is omitted.
The intensity of the light of the 1 st irradiation direction DL1 emitted from the 1 st light source LS1 is highest at the 1 st optical axis AX1,the 1 st optical axis AX1 is inclined at an angle Φ with respect to the 1 st main surface 51. Of the diffused light (diffused light) emitted from the 1 st light source LS1, the light most diffused toward the 1 st main surface 51 side is incident on the 1 st region a1 at the incident angle α, refracted, incident on the 1 st main surface 51 at the incident angle θ, and reflected. Here, the angle Φ, the angle α, and the angle θ are all acute angles. The angle theta is preferably the critical angle theta for total reflection on the 1 st main surface 51rThe above angle. Critical angle of total reflection thetarThe refractive index n of the light guide plate LG and the refractive index 1 of the air outside the light guide plate LG are expressed by the following formula (1).
Formula (1): thetar＝sin-1(1/n)
The angle theta is the critical angle theta of total reflectionrThe above angle is expressed by the following formula (2) based on the above formula (1), the angle θ 1, the angle α, and the refractive index n.
(2) θ ═ θ 1+ sin-1((l/n)sinα)≥θr
When equation (2) is solved for α, it is expressed by equation (3) below.
In formula (3), alpha is not less than sin-1(nsin(θr-θ1))
On the other hand, of the diffused lights emitted from the 1 st light source LS1, the light diffused to the farthest side from the 1 st main surface 51 is inclined at an angle β with respect to the 1 st main surface 51. The angle β and the angle θ 1 preferably satisfy the following formula (4).
Formula (4): beta < theta 1
If the relationship between the inclination angle of the light emitted from the 1 st light source LS1 and the inclination angle θ 1 of the 1 st region a1 of the light guide plate LG satisfies the above equations (2) to (4), it is preferable that the light emitted from the 1 st light source LS1 be efficiently transmitted through the light guide plate LG. Regarding the 2 nd light source LS2 and the 5 th region a5, the relationship between the inclination angle of light emitted from the 2 nd light source LS2 and the inclination angle θ 5 of the 5 th region a5 of the light guide plate LG is preferably configured to satisfy the same expressions as the above-described expressions (2) to (4).
Fig. 6 is an enlarged cross-sectional view of the 1 st prism P1. The 1 st prism P1 has a1 st inclined surface 11 and a2 nd inclined surface 12, and has a triangular cross section. The angle of the apex angle formed by the inclined surfaces 11 and 12 is θ a. The angle formed by the 2 nd main surface 52 and the 1 st inclined surface 11 in the 2 nd region a2 is θ b. The angle formed by the 2 nd main surface 52 and the 2 nd inclined surface 12 in the 2 nd region a2 is θ c. The width of the 1 st prism P1 in the 1 st direction X is Dp1, and the interval in the 1 st direction X of the adjacent 1 st prism P1 is Tp 1. The height of the 1 st prism P1 is H1.
In the example of fig. 6, the angle θ a is an obtuse angle, the angles θ b and θ c are acute angles, and θ a > θ c > θ b are true. For example, the 1 st inclined surface 11 is parallel to the 1 st main surface 51. In this case, the angle θ b is equal to the angle θ 1 described above. The 1 st prisms P1 formed in the 2 nd region a2 may have the same shape as a whole, or at least some of the 1 st prisms P1 may have different shapes.
Each of the 3 rd prisms P3 formed in the 4 th region a4 also has the same structure as the 1 st prism P1 described above.
The light emitted from the 1 st main surface 51 can be increased in the region where the number of the 1 st prisms P1 or the 3 rd prisms P3 is larger. In addition, generally, the luminance of the emission surface is likely to be lowered at the end of the light guide plate. In view of this, as shown in fig. 4, the density of the 1 st prisms P1 in the 2 nd region a2 may be increased from the boundary of each region a2, A3 toward the boundary of each region a1, a 2. Similarly, the density of the 3 rd prisms P3 in the 4 th region a4 may be increased from the boundary between the regions A3 and a4 to the boundary between the regions a4 and a 5.
Here, the density of the 1 st prisms P1 can be defined as, for example, the number of 1 st prisms P1 per unit length. Alternatively, the density of the 1 st prism P1 may be expressed by a ratio of the width Dp1 of the 1 st prism P1 to the interval Tp1 of the adjacent 1 st prism P1. The same applies to the density of the 3 rd prism P3.
The angle θ a of the apex angle of the 1 st prism P1 or the height H1 may be increased from the boundary between the regions a2 and A3 to the boundary between the regions a1 and a 2. In this case, the density of the 1 st prisms P1 in the 2 nd region a2 may be constant.
Similarly, the angle or height of the apex angle of the 3 rd prism P3 may be increased from the boundary of each of the regions A3 and a4 toward the boundary of each of the regions a4 and a 5. In this case, the density of the 3 rd prisms P3 in the 4 th region a4 may be constant.
The density, angle, and height adjustments described above do not necessarily need to be applied to all of the 1 st prism P1 and the 3 rd prism P3. For example, the density, angle, and height may be different in a part of each 1 st prism P1. Similarly, the density, angle, and height may be different in a part of each 3 rd prism P3.
Fig. 7 is an enlarged cross-sectional view of the 2 nd prism P2. The 2 nd prism P2 has the 1 st inclined surface 21 and the 2 nd inclined surface 22, and has a triangular cross section. The angle of the apex angle formed by the inclined surfaces 21 and 22 is θ d. The angle formed by the 2 nd main surface 52 and the 1 st inclined surface 21 in the 3 rd region a3 is θ e. The angle formed by the 2 nd main surface 52 and the 2 nd inclined surface 22 in the 3 rd region a3 is θ f. The width of the 2 nd prism P2 in the 1 st direction X is Dp2, and the interval in the 1 st direction X of the adjacent 2 nd prism P2 is Tp 2. The height of the 2 nd prism P2 is H2.
In the example of fig. 7, the angle θ d is an obtuse angle, the angles θ e and θ f are acute angles, and θ d > θ e and θ f are true. The angle θ e and the angle θ f are, for example, the same angle (θ e ═ θ f). The angle θ d and the height H2 of each 2 nd prism P2 formed in the 3 rd region a3 may be all the same, or may be different in at least a part of each 2 nd prism P2. The density of the 2 nd prisms P2 may be constant, or may be different in at least a part of the 2 nd prisms P2.
Here, the density of the 2 nd prisms P2 may be defined as, for example, the number of the 2 nd prisms P2 per unit length. Alternatively, the density of the 2 nd prism P2 can be represented by the ratio of the width Dp2 of the 2 nd prism P2 to the interval Tp2 of the adjacent 2 nd prism P2.
According to the structure of the light guide plate LG of the present embodiment, unevenness in luminance of light emitted from the 1 st main surface 51 can be suppressed, and light having a good luminance distribution can be irradiated onto the display panel 2. Further, by disposing the 1 st light source LS1 in the space below the light guide plate LG, the lighting device 3 and the display device 1 can be reduced in size, and the frame edge region can be narrowed. Further, since the 1 st irradiation direction DL1 and the 2 nd irradiation direction DX2 are inclined with respect to the 1 st main surface 51, light is less likely to leak out in the light guide plate LG than in the case of being parallel to the 1 st main surface 51, and light utilization efficiency can be improved. Effects of the present embodiment will be described with reference to fig. 8 to 11.
Fig. 8 is a diagram showing a luminance distribution on an emission surface of the light guide plate LGA according to the comparative example. The light guide plate LGA is a flat plate type having a constant thickness from one end (left side in the drawing) of the light source side to the other end (right side in the drawing). That is, the shape of the light guide plate LGA corresponds to the shape having the 4 th region a4, the 1 st region a1, the 2 nd region a2, the 3 rd region A3, and the 5 th region a5 on the light guide plate LG shown in fig. 4. The 9 light sources are arranged along the left end of the figure. In this comparative example, the luminance of the emission surface increases as it goes away from the light source. In a region closer to the light source, a stripe pattern in which a high-luminance portion and a low-luminance portion are repeated in the 2 nd direction Y occurs.
Fig. 9 is a graph showing a luminance distribution of an exit surface of a light guide plate LGB according to another comparative example. Fig. 10 is a schematic cross-sectional view of the light guide plate LGB. As shown in fig. 10, the light guide plate LGB has a shape in which the thickness increases from the left end toward the center C in the 1 st direction X and decreases from the center C toward the right end. That is, the light guide plate LGB has a shape corresponding to the shape having the 1 st region a1, the 2 nd region a2, the 4 th region a4, the 5 th region a5, and no 3 rd region A3 on the light guide plate LG shown in fig. 4. The plurality of light sources LS are disposed to face the 1 st region a1 and the 5 th region a5, respectively. In addition, although prisms similar to the 1 st prism P1 and the 3 rd prism P3 are disposed on the light guide plate LGB, they are not illustrated in fig. 10. Further, 5 light sources are arranged at the left end and 4 light sources are arranged at the right end.
The light from the light source LS disposed at the left end of the light guide plate LGB is mainly reflected by the prisms of the 4 th area a4 and is emitted from the emitting surface. The light from the light source LS disposed at the right end of the light guide plate LGB is mainly reflected by the prisms in the 2 nd area a2 and is emitted from the emission surface. Therefore, as shown in fig. 9, the luminance drop in the vicinity of the light source as shown in fig. 8 does not occur in this comparative example. However, the light reflected by the prism in the vicinity of the boundary between the regions a2 and a4 is not easily emitted from the position directly above the boundary, but is emitted from a position away from the boundary. For this reason, the luminance of the emission surface is greatly reduced in the vicinity of the center C in the 1 st direction X (in the vicinity of the boundary between the regions a2 and a 4).
Fig. 11 is a diagram showing a luminance distribution of the emission surface (the 1 st main surface 51) of the light guide plate LG according to the present embodiment. In the example of the figure, since the 3 rd region A3 is provided between the regions a2 and a4, the luminance in the vicinity of the center does not decrease. That is, since the light from the light sources LS1 and LS2 is also emitted from the emission surface (the 1 st main surface 51) near the center by the 2 nd prism P2 in the 3 rd region a3, the brightness unevenness as shown in fig. 9 is suppressed.
According to the present embodiment described above, by providing the 3 rd region a3 on the light guide plate LG, a favorable luminance distribution of the 1 st main surface 51 can be obtained. Further, by using the lighting device 3 including the light guide plate LG, the display quality of the display device 1 can be improved.
In addition, according to the present embodiment, the above-described various appropriate effects can be obtained.
[ 2 nd embodiment ]
Embodiment 2 will be explained. The configuration and effects not particularly described are the same as those in fig. 4 and the like of embodiment 1.
Fig. 12 is a diagram showing a schematic configuration of the illumination device 3 according to embodiment 2. The lighting device 3 includes the 1 st reflecting member 60 in addition to the 1 st light source LS1, the 2 nd light source LS2, and the light guide plate LG. The 1 st reflecting member 60 is, for example, a plate material (sheet) made of a metal material, and faces the 2 nd main surface 52 of the light guide plate LG. The 1 st reflecting member 60 reflects the light leaking from the 2 nd main surface 52 of the light guide plate LG toward the light guide plate LG. In addition, the prism group on the 2 nd main surface 52 is omitted.
The 1 st reflecting member 60 has a1 st portion 61 opposed to the 2 nd region a2, a2 nd portion 62 opposed to the 3 rd region A3, and A3 rd portion 63 opposed to the 4 th region a 4. The 1 st portion 61 is parallel to the 2 nd region a2, the 2 nd portion 62 is parallel to the 3 rd region A3, and the 3 rd portion 63 is parallel to the 4 th region a 4.
Even when the 1 st reflecting member 60 is provided as in embodiment 3 shown in fig. 12, a luminance distribution as good as that of embodiment 1 can be obtained. Further, when the 1 st reflecting member 60 is provided, the light leaking from the 2 nd main surface 52 of the light guide plate LG can be reused, and therefore, the luminance of the 1 st main surface 51 can be improved as a whole. The 1 st portion 61, the 2 nd portion 62, and the 3 rd portion 63 may be formed not parallel to the 2 nd region a2, the 3 rd region A3, and the 4 th region a4, respectively.
[ embodiment 3 ]
Embodiment 3 will be explained. The same structure and effects as those of the above embodiments are not particularly described.
Fig. 13 is a schematic cross-sectional view of the lighting device 3 according to embodiment 3. The lighting device 3 includes a light guide plate LG, a1 st light source LS1, and a1 st reflecting member 60. The lighting device 3 does not include the 2 nd light source LS 2. The 2 nd main surface 52 of the light guide plate LG has a1 st region a1, a2 nd region a2, and A3 rd region A3. Although not shown here, a plurality of 1 st prisms P1 are formed in the 2 nd region a2, and a plurality of 2 nd prisms P2 are formed in the 3 rd region A3.
The distance D1, which is the thickness of the light guide plate LG in the 1 st region a1, increases from the 1 st side surface 53 toward the boundary of the regions a1 and a 2. Similarly, the distance D2, which is the thickness of the light guide plate LG in the 2 nd region a2, increases from the boundary between the 1 st region a1 and the 2 nd region a2 toward the boundary between the 2 nd region a2 and the 3 rd region A3. In the example of fig. 13, the distance D3, which is the thickness of the light guide plate LG in the 3 rd region a3, is constant. As in embodiment 1, the distance D3 is longer than the distances D1 and D2 at any position of the 1 st region a1 and the 2 nd region a2 (D3> D1, D2).
The 1 st reflecting member 60 has a1 st portion 61 opposed to the 2 nd region a2 and a2 nd portion 62 opposed to the 3 rd region A3. The 1 st part 61 is parallel to the 2 nd region a2 and the 2 nd part 62 is parallel to the 3 rd region A3. In addition, the 1 st portion 61 and the 2 nd region a2 may not be parallel, and the 2 nd portion 62 and the 3 rd region A3 may not be parallel.
The lighting device 3 further includes a2 nd reflecting member 70. The 2 nd reflecting member 70 is, for example, a plate material (sheet material) made of a metal material, and faces the 2 nd side surface 54 of the light guide plate LG. The 2 nd reflecting member 70 is parallel to the 2 nd side surface 54.
In fig. 13, an example of the optical path of the light emitted from the 1 st light source LS1 is shown by a broken line. The light emitted from the 1 st light source LS1 enters the light guide plate LG from the 1 st region a 1. If the 2 nd region a2 is inclined as shown in fig. 13, the light is irradiated onto the 2 nd region a2 at a shallow angle, and therefore, the total reflection conditions of the main surfaces 51 and 52 are not easily deviated. Therefore, the light propagates through the light guide plate LG while being reflected by the main surfaces 51 and 52, and reaches the 2 nd side surface 54. The light can be emitted from the 2 nd side surface 54, but is reflected by the 2 nd reflecting member 70 and again enters the light guide plate LG. The light returning to the light guide plate LG is reflected by the 1 st prism P1 in the 1 st region a1 or the 2 nd prism P2 in the 2 nd region a2, and exits from the 1 st main surface 51 out of the total reflection condition of the 1 st main surface 51.
If the 3 rd region a3 is not provided, the light reflected by the 2 nd reflecting member 70 is emitted from the 1 st main surface 51 in the vicinity of the 1 st side surface 53 in a large amount, and the luminance unevenness may occur on the 1 st main surface 51. On the other hand, when the 3 rd region a3 is provided, such luminance unevenness can be suppressed and the uniformity of the luminance distribution of the 1 st main surface 51 can be improved as in the case of the 1 st embodiment.
[ 4 th embodiment ]
Embodiment 4 will be explained. The same structure and effects as those of the above embodiments are not particularly described.
Fig. 14 is a schematic cross-sectional view of a part of the lighting device 3 according to embodiment 4. The lighting device 3 includes a light guide plate LG, a1 st light source LS1, and a1 st reflecting member 60. In fig. 14, the prism P1 is not shown. As shown in the drawing, the 1 st region a1 of the 2 nd main surface 52 of the light guide plate LG is a curved surface curved in a convex lens shape. The curved surface extends parallel to the 2 nd direction Y in the illustrated cross-sectional shape, for example. If the 1 st region a1 is configured in this way, the diffusion angle of light emitted from the 1 st light source LS1 can be adjusted by the 1 st region a1 functioning like a convex lens.
For example, when the 1 st light source LS1 includes a plurality of light emitting elements that emit light of different colors, the diffusion angles of the light emitted by the light emitting elements may be different from each other. At this time, the diffusion angle of the light emitted from each light emitting element can be adjusted by adjusting the curvature of the convex lens-shaped curved surface provided in the 1 st region a1 according to the diffusion angle of the light emitted from each light emitting element. Therefore, compared to embodiment 1, the color unevenness and the luminance unevenness of the 1 st main surface 51 can be further suppressed, and the uniformity of the luminance distribution of the 1 st main surface 51 can be improved.
In addition, the 5 th region a5 and the 2 nd light source LS2 can also be configured in the same manner as the 1 st region a1 and the 1 st light source LS1 disclosed in this embodiment.
[ 5 th embodiment ]
Embodiment 5 will be described. The same structure and effects as those of the above embodiments are not particularly described.
Fig. 15 is a schematic cross-sectional view of a part of the lighting device 3 according to embodiment 5. The lighting device 3 includes a light guide plate LG, a1 st light source LS1, and a1 st reflecting member 60. In fig. 15, the prism P1 is not shown. The 1 st light source LS1 includes a plurality of light emitting elements LS 1-1 to LS 1-3 that emit light of different colors, respectively. The plurality of light emitting elements LS 1-1, LS 1-2, and LS 1-3 are respectively disposed to face the 1 st region a1, and are arranged along the inclined side of the 1 st region a1 in order from the 1 st side surface 53 toward the boundaries of the 1 st region a1 and the 2 nd region a 2. A plurality of light emitting elements LS 1-1 to LS 1-3 are arranged in parallel to the 2 nd direction Y in the illustrated cross-sectional shape, for example.
In general, the shorter the wavelength of light, the greater the absorptivity of light in the light guide plate LG. The wavelengths of the red, green, and blue lights are blue < green < red. Thus, the light absorption of the light guide plate LG is blue > green > red. In the shape of the light guide plate LG shown in fig. 15, the light paths of the light emitted from the light emitting elements LS 1-1 to LS 1-3 through the light guide plate LG are LS 1-3 < LS 1-2 < LS 1-1. Therefore, if the absorption of light in the light guide plate LG is considered, it is preferable that the light emitting elements which emit light having shorter wavelengths are arranged on the 2 nd region a2 side in the cross-sectional view. That is, the light emitting elements LS 1-1, LSI-2, and LS 1-3 are preferably a red laser light source that emits a red laser beam, a green laser light source that emits a green laser beam, and a blue laser light source that emits a blue laser beam, for example. When the outputs of the light emitting elements LS 1-1 to LSI-3 are different, the light emitting element LS 1-1 with the largest output, the light emitting element LS 1-2 with the next larger output, and the light emitting element LS 1-3 with the smallest output may be used.
With the above configuration, the same effects as those of the above embodiments can be obtained. Further, by changing the arrangement in accordance with the characteristics of the light emitted from the light emitting elements LS 1-1 to LS 1-3 as in the present embodiment, it is possible to further suppress color unevenness and luminance unevenness of the 1 st main surface 51 and improve uniformity of the luminance distribution of the 1 st main surface 51.
In fig. 15, the number of the plurality of light-emitting elements facing the 1 st region a1 in cross section is not limited to 3, and may be 2, 4, or 5 or more.
In addition, the 5 th region a5 and the 2 nd light source LS2 can also be configured in the same manner as the 1 st region a1 and the 1 st light source LS1 disclosed in this embodiment.
[ 6 th embodiment ]
Embodiment 6 will be described. The same structure and effects as those of the above embodiments are not particularly described.
Fig. 16 is a schematic cross-sectional view of a part of the lighting device 3 according to embodiment 6. The lighting device 3 includes a light guide plate LG, a1 st light source LS1, a1 st reflecting member 60, a3 rd reflecting member 80, and a frame FM. In fig. 16, the prism P1 is not shown. The frame FM is formed of, for example, a metal material having light-shielding properties. The frame FM surrounds, for example, the 1 st light source LS1, the light guide plate LG and the 1 st light source LS1, and the back surface side (the 2 nd main surface 52 side) of the 1 st reflecting member 60.
The 3 rd reflecting member 80 is, for example, a mirror member. The 1 st light source LS1 and the 3 rd reflecting member 80 are arranged in a space surrounded by the light guide plate LG and the frame FM so as to overlap the 1 st region a1 in the thickness direction (the 3 rd direction Z) of the light guide plate LG. The 3 rd reflecting member 80 reflects the light emitted from the 1 st light source LS1 and irradiates the 1 st region a1 of the light guide plate LG.
In fig. 16, an example of the optical path of the light emitted from the 1 st light source LS1 is shown by a broken line. The light emitted from the 1 st light source LS1 is reflected by the 3 rd reflecting member 80, and the light path is changed in the 1 st irradiation direction DL1 to be irradiated to the 1 st region a1, and propagates through the light guide plate LG while being reflected by the main surfaces 51 and 52 of the light guide plate LG.
With the above configuration, the same effects as those of the above embodiments can be obtained. Further, by using the 3 rd reflecting member 80 as in this embodiment, it is not necessary to incline the 1 st light source LS1 in the 1 st irradiation direction DL1, and the irradiation direction of the light irradiated to the 1 st region a1 can be easily adjusted by adjusting the angle of the 1 st reflecting member 60. Further, by using the 3 rd reflecting member 80 as in the present embodiment, the degree of freedom of the arrangement position of the 1 st light source LS1 is increased. In the example of fig. 10, since the 1 st light source LS1 is disposed in contact with the frame FM, heat dissipation from the 1 st light source LS1 is facilitated.
The 3 rd reflecting member 80 may reflect the light from the 1 st light source LS1 only 1 time and irradiate the light onto the 1 st area a1, or may reflect the light 2 times or more and irradiate the light onto the 1 st area a 1.
The lighting device 3 may include a condenser lens disposed to face the 1 st light source LS1 and configured to adjust the diffusion angle of light emitted from the 1 st light source LS 1. By using the condenser lens, the light emitted from the 1 st light source LS1 can be accurately irradiated by the 3 rd reflecting member 80.
In addition, the configuration described in the vicinity of the 1 st light source LS1 in the present embodiment can be applied to the 2 nd light source LS2 side as well.
[ 7 th embodiment ]
Embodiment 7 will be described. The same structure and effects as those of the above embodiments are not particularly described.
Fig. 17 is a schematic cross-sectional view of a part of the lighting device 3 according to embodiment 7. The lighting device 3 includes a light guide plate LG, a1 st light source LSI and a1 st reflecting member 60, a frame FM, and a bending member 90.
The 1 st light source LS1 overlaps with the 2 nd region a2 in the thickness direction (the 3 rd direction Z) of the light guide plate LG. A part of the bending member 90 overlaps the 1 st region a1 in the thickness direction (3 rd direction Z) of the light guide plate LG. The 1 st light source LS1 and the bending member 90 are disposed in a space surrounded by the light guide plate LG and the frame FM. The bending member 90 shown in fig. 17 is a prism whose shape in the X-Z section is triangular and which extends in the 2 nd direction Y. Specifically, the bending member 90 has a1 st surface 91, a2 nd surface 92, and a3 rd surface 93. For example, as shown in fig. 3, the bending member 90 may be provided with 1 light source LS1 of the 1 st light sources LS1 arranged in the 2 nd direction Y. The bending member 90 may be provided for 1 of each of 2 or more 1 st light sources LS1, or may be provided for 1 of all 1 st light sources LS 1.
The 1 st surface 91 has an incident region 91a and an emission region 91 b. The incident region 91a is opposed to the 1 st light source LS 1. The emission region 91b faces the 1 st region a1 of the light guide plate LG. In the example of fig. 17, the 1 st plane 91 is inclined with respect to the 3 rd direction Z. The 2 nd surface 92 and the 3 rd surface 93 are inclined at a predetermined angle with respect to the 1 st surface 91. The angle formed by the 2 nd surface 92 and the 1 st surface 91 and the angle formed by the 3 rd surface 93 and the 1 st surface 91 may be the same or different.
The light emitted from the 1 st light source LS1 is incident from the incident region 91a toward the bending member 90. The incident light is reflected by the 2 nd surface 92, further reflected by the 3 rd surface 93, and is emitted from the emission region 91 b. The emitted light is irradiated onto the 1 st side surface 53 of the light guide plate LG along the 1 st irradiation direction DL1, and propagates through the light guide plate LG while being reflected by the main surfaces 51 and 52 of the light guide plate LG. In this way, in the present embodiment, the optical path of the light emitted from the 1 st light source LS1 is bent in the 1 st irradiation direction DL1 by the bending member 90 and enters the light guide plate LG.
With the above configuration, the same effects as those of the above embodiments can be obtained. In this configuration, the same effects as those of embodiment 6 can be obtained by using the bending member 90 as in this embodiment.
In addition, the configuration described in the vicinity of the 1 st light source LS1 in the present embodiment can be similarly applied to the 2 nd light source LS2 side.
[ 8 th embodiment ]
Embodiment 8 will be described. The same structure and effects as those of the above embodiments are not particularly described.
Fig. 18 is a schematic cross-sectional view of an illumination device 3' according to embodiment 8. The lighting device 3' includes 3 lighting devices 3 shown in fig. 12 in cross section, and the plurality of lighting devices 3 are arranged adjacent to each other in the 1 st direction X. LG1 to LG3 included in the 3 lighting devices 3 have the same structure as LG included in the lighting device 3 shown in fig. 12. The illumination device 3' is configured by arranging the illumination devices 3 having the illustrated cross-sectional shapes adjacent to each other in the 2 nd direction Y, for example.
With the above configuration, the same effects as those of the above embodiments can be obtained. Further, by disposing a plurality of small illumination devices 3 adjacent to each other, it is possible to construct a large illumination device 3 'without increasing the thickness of the illumination device 3'. In the illumination device 3' having such a configuration, the contrast can be improved and power can be saved by partially driving the illumination device 3. In addition, in the lighting device 3', it can be bent at the boundary portion of the adjacent lighting devices 3, and the degree of freedom of the shape thereof is improved.
In fig. 18, an example is shown in which 3 lighting devices 3 are arranged adjacent to each other in the 1 st direction X in cross section, but the number is not limited to this, and 2 or 4 lighting devices may be provided, or 5 or more lighting devices may be provided. The plurality of illumination devices 3 constituting the illumination device 3' are not limited to the illumination device 3 shown in fig. 12, and may be any of the illumination devices 3 according to the above-described embodiments, or may be illumination devices 3 according to embodiments different from each other.
[ 9 th embodiment ]
Embodiment 9 will be explained. The same structure and effects as those of the above embodiments are not particularly described.
Fig. 19 is a schematic cross-sectional view of a part of the lighting device according to embodiment 9. The lighting device 3 shown in fig. 19 is a modification of the lighting device 3' shown in fig. 18, and is a diagram showing a boundary portion between 2 light guide plates LG1 and LG2 in an enlarged manner. The illumination device 3 'shown in fig. 19 does not include the 2 nd light source LS2, but includes the 4 th reflecting member 100, as compared with the illumination device 3' shown in fig. 18.
The 1 st light source LS1 and the 4 th reflecting member 100 are arranged on the boundary line of the 2 light guide plates LG1 and LG2 in the thickness direction (3 rd direction Z) of the light guide plate LG. The 4 th reflecting member 100 shown in fig. 17 has a V-shape in the X-Z cross section, and is a mirror member extending in the 2 nd direction Y. Specifically, the 4 th reflecting member 100 has a1 st surface 101 and a2 nd surface 102. For example, the 4 th reflecting member 100 may be provided with 1 light source LS1 of the 1 st light sources LS1 arranged in the 2 nd direction Y. The 4 th reflecting member 100 may be provided for 1 of each of 2 or more 1 st light sources LS1, or may be provided for 1 of all 1 st light sources LS 1.
In the example of fig. 19, the 1 st surface 101 is inclined at a predetermined angle with respect to the 3 rd direction Z and faces the 5 th region a5 of one light guide plate LG 1. The 2 nd surface 102 is inclined at a predetermined angle with respect to the 3 rd direction Z and faces the 1 st region a1 of the other light guide plate LG 2. The 1 st surface 91 and the 2 nd surface 92 also face the 1 st light source LS 1.
In fig. 19, an example of the optical path of light emitted from the 1 st light source is shown by a broken line. In the illustrated example, the light emitted from the 1 st light source LS1 is emitted in the 3 rd direction Z and reflected by the 1 st surface 91 and the 2 nd surface 92 of the 4 th reflecting member 100. The light reflected by the 1 st surface 101 and having its optical path changed to the 2 nd irradiation direction DL2 is irradiated on the 5 th region a5 of one light guide plate LG1 and propagates through the light guide plate LG1 while being reflected by the main surfaces 51 and 52 of the light guide plate LG 1. On the other hand, the light reflected by the 2 nd surface and redirected to the 1 st irradiation direction DL1 is irradiated to the 1 st region a1 of the other light guide plate LG2, and propagates through the light guide plate LG2 while being reflected by the main surfaces 51 and 52 of the light guide plate LG.
With the above configuration, the same effects as those of the above embodiments can be obtained. In this configuration, the number of the light sources LS1 and LS2 can be reduced as compared with the above embodiments. The plurality of illumination devices 3 constituting the illumination device 3' are not limited to the illumination device 3 shown in fig. 12, and may be any of the illumination devices according to the above-described embodiments. For example, when 2 illumination devices 3 having the same configuration as the illumination device 3 shown in fig. 13 are adjacent to each other, the 1 st light source LS1 and the 4 th reflecting member 100 may be provided instead of the 21 st light sources LS1 so that the 1 st side surfaces 53 of the light guide plate LG are adjacent to each other.
As described above, all the illumination devices and display devices that can be implemented by appropriate design changes by those skilled in the art based on the illumination devices and display devices described as the embodiments of the present invention also fall within the scope of the present invention as long as the gist of the present invention is included.
In the scope of the technical idea of the present invention, if various modifications are conceivable to those skilled in the art, those modifications should be understood to fall within the scope of the present invention. For example, a person skilled in the art may add, delete, or modify a design of a component or add, omit, or modify a condition of a process as appropriate to each of the above embodiments, and the scope of the present invention is included as long as the person is in the spirit of the present invention.
It should be noted that other operational effects of the technical means described in the embodiments are naturally the effects of the present invention, as can be understood from the description of the present specification or as can be appropriately conceived by a person skilled in the art.
Drawings
1a display device; 2 a display panel; 3, a lighting device; SUB1 substrate 1; SUB2 substrate No. 2; an LC liquid crystal layer; a DA display area; LG light guide plate; a PS prism sheet; a DS diffusion sheet; 51 a first main surface; 52 a2 nd main surface; 53, side 1; 54 side 2; regions 1 to 3 of A1 to A3; P1-P3 No. 1-No. 3 prisms; LS1 light source No. 1; LS2 light source No. 2; VL 1-VL 3 No. 1-No. 3 imaginary lines; 60 a1 st reflecting member; 61 to 63, 1 st to 3 rd; 70 a2 nd reflecting member; an FM frame; 80 a3 rd reflecting member; 90 a curved member; 100 th reflecting part.

Claims (11)

1. A lighting device is provided, which comprises a lighting unit,
the disclosed device is provided with:
a light guide plate having a1 st main surface and a2 nd main surface opposite to the 1 st main surface and including a plurality of surfaces;
a1 st light source for irradiating laser along a1 st irradiation direction; and
a plurality of prisms provided on the 2 nd main surface;
the laser beam advances in a1 st advancing direction in a plan view;
the 2 nd main surface has a1 st region, a2 nd region and a3 rd region arranged in this order along the 1 st traveling direction,
the light emitted from the 1 st light source enters the 1 st region;
the plurality of prisms include a plurality of 1 st prisms in the 2 nd region;
in a cross-sectional view, distances from the 1 st region, the 2 nd region, and the 3 rd region to the 1 st main surface are longer in the order of the 1 st region, the 2 nd region, and the 3 rd region;
the 1 st irradiation direction is inclined with respect to the 1 st main surface,
the density of the plurality of 1 st prisms in the 2 nd region increases from the boundary between the 2 nd region and the 3 rd region toward the boundary between the 2 nd region and the 1 st region,
the plurality of prisms further includes a plurality of 2 nd prisms in the 3 rd region,
the 1 st prism and the 2 nd prism are different in shape from each other, and the 1 st prism and the 2 nd prism are arranged at different densities,
a2 nd virtual line connecting apexes of the 2 nd prisms is parallel to the 1 st main surface.
2. The lighting device as set forth in claim 1,
at least a part of the 1 st light source overlaps with the 1 st region or the 2 nd region in a plan view.
3. The lighting device as set forth in claim 1,
further comprises a1 st reflecting member;
the light emitted from the 1 st light source is reflected by the 1 st reflecting member to change the optical path to the 1 st irradiation direction, and is irradiated to the 1 st area.
4. The lighting device as set forth in claim 1,
in a cross-sectional view, the 1 st region is inclined with respect to the 1 st main surface with respect to a1 st virtual line connecting apexes of the 1 st prisms.
5. The lighting device as set forth in claim 1,
the 1 st light source includes a plurality of light emitting elements;
in a cross-sectional view, the plurality of light emitting elements are arranged along the inclined side of the 1 st region.
6. The lighting device as set forth in claim 5,
the plurality of light emitting elements emit light of different wavelengths;
in a cross-sectional view, the shorter the wavelength of light emitted from the plurality of light emitting elements is, the closer to the 2 nd region side.
7. The lighting device as set forth in claim 1,
the 1 st region is curved in a convex shape.
8. The lighting device as set forth in claim 1,
the 2 nd imaginary line is inclined with respect to a1 st imaginary line connecting apexes of the 1 st prisms.
9. The lighting device as set forth in claim 1,
a2 nd reflecting member facing the 2 nd main surface;
the 2 nd reflecting member includes a1 st portion facing the 2 nd region and a2 nd portion facing the 3 rd region.
10. The lighting device as set forth in claim 1,
the 2 nd main surface has the 1 st region, the 2 nd region, the 3 rd region, the 4 th region, and the 5 th region arranged in this order along the 1 st traveling direction;
the lighting device further includes a2 nd light source for irradiating the 5 th region of the light guide plate with light;
the plurality of prisms include a plurality of 3 rd prisms in the 4 th region;
in a cross-sectional view, the 5 th region and a3 rd imaginary line connecting apexes of the plurality of 3 rd prisms in the 4 th region are inclined with respect to the 1 st main surface;
in a cross-sectional view, distances between the 5 th region, the 4 th region, and the 3 rd region and the 1 st main surface are longer in the order of the 5 th region, the 4 th region, and the 3 rd region.
11. A lighting system is provided, which comprises a lighting unit,
comprising a plurality of lighting devices according to claim 1,
the plurality of lighting devices are arranged adjacent to each other in a plan view.
CN201810161055.9A 2017-04-19 2018-02-27 Lighting device Active CN108732675B (en)

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