CN105527672A - Area light source device, display device and electronic device - Google Patents

Area light source device, display device and electronic device Download PDF

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Publication number
CN105527672A
CN105527672A CN201510679259.8A CN201510679259A CN105527672A CN 105527672 A CN105527672 A CN 105527672A CN 201510679259 A CN201510679259 A CN 201510679259A CN 105527672 A CN105527672 A CN 105527672A
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CN
China
Prior art keywords
light
light source
guide plate
directive property
changing patterns
Prior art date
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Granted
Application number
CN201510679259.8A
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Chinese (zh)
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CN105527672B (en
Inventor
仓田刚大
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Northeast Electronics Co.,Ltd.
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Omron Corp
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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
    • G02B6/0013—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
    • G02B6/0013—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
    • G02B6/0018—Redirecting means on the surface 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
    • G02B6/0013—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
    • G02B6/002—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 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
    • G02B6/0021—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 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces for housing at least a part of the light source, e.g. by forming holes or recesses
    • 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
    • G02B6/002—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 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
    • 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
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Planar Illumination Modules (AREA)
  • Liquid Crystal (AREA)
  • Fastening Of Light Sources Or Lamp Holders (AREA)
  • Light Guides In General And Applications Therefor (AREA)

Abstract

The invention provides an area light source device, a display device and an electronic device. The objective of the invention is to provide a thin type area light source device which is capable of shortening space of a carried light source and increasing brightness of illumination light and is quite high in reliability. An inclining part is arranged on a light guiding plate of an area light source device body and is configured between a light incident plane and a light exit plane. The thickness of the inclining part decreases along from the light incident plane to the light exit plane. A notch part with a face which is perpendicular to the light incident plane is formed on an inclining face of the inclining part. A recessed-protruding structure which is used for increasing contact area with an adhesion layer on a printed circuit substrate of a light source is formed on a face which is perpendicular to the light incident plane in the notch part.

Description

Planar light source device, display device and electronic equipment
Technical field
The present invention relates to planar light source device, display device and electronic equipment.
Background technology
In recent years, the miniaturization of electronic equipment, slimming achieve progress.Needs for the narrow margo frontalis or slimming obtaining larger viewing area in identical area are existed for the liquid crystal indicator be equipped on such electronic equipment.The backlight of liquid crystal indicator such as have employed the LED (LightEmittingDiode: light emitting diode) of injection white light as light source and from the side to the planar light source device of the sidelight type (being also called edge-light (edgelight) mode) of light guide plate (being also called light guide (lightguide)) incident light.
In addition, be known to following such situation: in order to correspond to the further slimming of mobile information apparatus, and light inlet end face with formed between injection part thickness along with being separated with light inlet end face rake decrescence.By forming rake (dip plane) like this near the light inlet end face of light guide plate, the lower thickness of the injection part of light guide plate can be made, and have nothing to do with the thickness of LED.
Here, LED is typically configured to: under the state being installed on OBL tellite, with the light inputting end of light guide plate in the face of to.Further, by by be provided be positioned at the part in front and the injection part of light guide plate compared with the part of the LED of tellite light inlet end face near be close to fixing, come light guide plate location fixed L ED.Like this, when not forming rake near the light inlet end face of light guide plate, be close to by tellite under the state be fixed in light guide plate, LED configures with the mode subtend that its light-emitting area is parallel with the light inlet end face of light guide plate.
But when being formed with dip plane near the light inlet end face of light guide plate, under the state that tellite is close to the dip plane being fixed on light guide plate, LED cannot configure with the mode subtend that its light-emitting area is parallel with the light inlet end face of light guide plate.That is, there is following situation: because the light inlet end face of light guide plate does not have orthogonal with dip plane, so a part of light sent from the light-emitting area of LED does not incide the light inlet end face of light guide plate, but leak into outside, cause the guide-lighting efficiency reduction of light guide plate.In addition, even if when tellite is close to be fixed on injection plane light inlet end face near or in dip plane any one, also there is following situation: near the light inlet end face inciding injection plane or when the light of dip plane reflects, printed circuit substrate absorbed, and the brightness of illumination light also can be caused thus to reduce.
On the other hand, light guide plate be formed between above-mentioned light inlet end face and above-mentioned injection part thickness to injection part side rake decrescence, and constitute the reply portion forming notch on the dip plane of above-mentioned rake in the region of removing light source forward portion, this notch has vertically maintain tellite and the plane that can paste on light inlet end face.Thus, in the region of the forward portion of the removing light source in the dip plane being formed at the rake in light guide plate, be formed with the horizontal zone for pasting tellite.Therefore, it is possible to flatly fix tellite in light guide plate, and the printed circuit substrate of light can be suppressed to absorb, consequently can realize the high brightness of illumination light.
But, in above-mentioned such liquid crystal indicator, need the visual identity of display frame further to improve, need high brightness for the planar light source device on such liquid crystal indicator.In the past, owing to also there is the requirement of the low-power consumption to planar light source device, so the improvement under mainly considering how to improve the such viewpoint of brightness while the number as far as possible reducing light source, but due to the increase of the battery capacity of electronic equipment in recent years itself or the improvement etc. of charging environment, the requirement of low-power consumption was reduced than in the past, therefore can also select the spacing by shortening the light source carried on planar light source device and carry more light source to make light quantity increase improve the such means of brightness.
And, when shortening the spacing of the light source carried on planar light source device, the narrowed width of the above-mentioned notch in tellite, the bond area of tellite and notch reduces, result is, sometimes tellite reduces the bounding force of light guide plate or bonding force, causes the reduction of reliability.
Prior art document
Patent documentation
No. 5278635th, [patent documentation 1] Jap.P.
[patent documentation 2] Japanese Unexamined Patent Publication 2011-96523 publication
[patent documentation 3] Japanese Unexamined Patent Publication 2014-146535 publication
The open WO2008/153024 pamphlet of [patent documentation 4] Japan internationality
The open WO2010/070821 pamphlet of [patent documentation 5] Japan internationality
Summary of the invention
Invent problem to be solved
The present invention in view of above-mentioned prior art problem points and make, its objective is, the spacing that can shorten the light source carried on planar light source device, the brightness that can improve illumination light and the higher slim planar light source device of reliability are provided.
The means of dealing with problems
Be characterised in that for solving the of the present invention maximum of above-mentioned problem, the light guide plate of planar light source device is provided with rake, this rake is configured between light entrance face and light-emitting face, its thickness reduces along with from light entrance face lateral light exit facet side, the dip plane of this rake defines the notch with the face vertical with light entrance face, and the face vertical with described light entrance face in notch is formed with the sag and swell making to increase with the contact area of the bonding coat on the tellite of light source.
In more detail, a kind of planar light source device possesses: tellite, light source, it is arranged on described tellite, and light guide plate, it imports the light sent by described light source from light entrance face, the light of this importing is guided to light-emitting face and penetrates with planar, the feature of this planar light source device is, described light guide plate is provided with rake, this rake is arranged between described light entrance face and described light-emitting face, its thickness reduces along with from light-emitting face side described in described light entrance face side direction, the dip plane on the surface as described rake defines the notch with the face intersected with described light entrance face, described tellite is glued to the described notch of described rake, thus described light source is configured to relative with described light entrance face, the face vertical with described light entrance face of described notch is formed the sag and swell that the contact area between the bonding coat making and be arranged on described tellite increases.
Thus, increase by the contact area making and be arranged between the bonding coat on tellite, come into the bounding force between a reinforcement notch and tellite or bonding force.Even if as a result, when shorten the light source carried on planar light source device spacing, improve the brightness of illumination light, the constant intensity of light source also can be made to improve, maintain or raising as the reliability of planar light source device.
In addition, in the present invention preferably, the height of described sag and swell is less than the thickness of described bonding coat.Thus, the bonding coat of tellite can contact with the surface integral of the sag and swell of described notch more reliably, can strengthen the bounding force between notch and tellite or bonding force further.
In addition, in the present invention, the height of described sag and swell can become less than 30 μm.Here generally, be less than 100 μm for pasting the thickness of the double-sided belt of tellite in light guide plate, the thickness of bonding coat is less than 40 μm.Thus, by making the height of sag and swell become less than 30 μm, the adhesive linkage of tellite is made to contact with the surface integral of the sag and swell of described notch more reliably.As a result, the bounding force can strengthened further between notch and tellite or bonding force.
In addition, in the present invention, described sag and swell can be that the groove be made up of the multiple groove being formed as extending on the direction vertical with described light entrance face constructs.In addition, the cross section that the groove in described groove structure can become the direction parallel with described light entrance face is the V-type groove of V-shape.Thus, man-hour is being added to the forming model of forming light guide plate, sag and swell can formed more simply on notch.
In addition, in the present invention, described groove can be formed as the cross section in the direction parallel with described light entrance face is that left and right is asymmetric about groove center.Thus, to making the forming model of forming light guide plate add man-hour, the lathe tool (バ イ ト) identical with the structure constructed for the formation of other groove with various function in light guide plate can be utilized to process the sag and swell of notch, the productivity of light guide plate can be made to improve.
In addition, in the present invention, the 1st directive property changing patterns can be provided with on the dip plane on the surface as described rake, 1st directive property changing patterns makes to be transformed to from the directive property broadening of light on the thickness direction of described light guide plate of described light entrance face incidence the directional property that the direction parallel to the direction, face with this light guide plate tilt, and described 1st directive property changing patterns is configured to crest line and valley line and alternately repeats along the Width of described light guide plate.Thus, to making the forming model of forming light guide plate add man-hour, identical lathe tool can be utilized to process described 1st directive property changing patterns and described sag and swell continuously, the productivity of light guide plate can be improved further.In addition, in the present invention, as long as make described sag and swell consistent with the crest line in described 1st directive property changing patterns, just can to making the forming model of forming light guide plate add man-hour, 1st directive property changing patterns and described sag and swell described in Continuous maching, can improve the productivity of light guide plate further more reliably.
In addition, in the present invention, be provided with terminal part between the described rake in described light guide plate and described light-emitting face, this terminal part has the second dip plane that pitch angle is relaxed than the dip plane as the surface of described rake,
Second dip plane of described terminal part is provided with the 2nd directive property changing patterns, 2nd directive property changing patterns disperses on the Width of described light guide plate by making the light guided by described rake, the light quantity of the light penetrated from described light-emitting face is become evenly
Described 2nd directive property changing patterns is configured to crest line and valley line and alternately repeats along the Width of described light guide plate.
Thus, to making the forming model of forming light guide plate add man-hour, same lathe tool can be utilized to process described 1st directive property changing patterns, described 2nd directive property changing patterns and described sag and swell continuously, the productivity of light guide plate can be improved more significantly.In addition, in the present invention, as long as make the crest line in described sag and swell, described 1st directive property changing patterns and described 2nd directive property changing patterns consistent, just can to making the forming model of forming light guide plate add man-hour, 1st directive property changing patterns and described sag and swell described in Continuous maching, can improve the productivity of light guide plate further more reliably.
In addition, the present invention can be following such liquid crystal indicator, it is characterized in that the liquid crystal panel possessing described planar light source device and accept the light penetrated from this planar light source device.In such display device, because possess planar light source device of the present invention, so high brightness can be provided, there is good display quality and the high display device of reliability.
In addition, the present invention can be the electronic equipment possessing described liquid crystal indicator.In such electronic equipment, because possess the display device adopting planar light source device of the present invention, so high brightness can be provided, there is good display quality and the high electronic equipment of reliability.
In addition, in the present invention, said units can be used as far as possible in combination.
Invention effect
According to the present invention, the spacing of the light source carried on planar light source device can be shortened, the brightness of illumination light can be improved, and reliability can be improved further.
Accompanying drawing explanation
Fig. 1 is the exploded perspective view that planar light source device in embodiments of the invention and liquid crystal panel are shown.
Fig. 2 is the exploded perspective view of the planar light source device in embodiments of the invention.
Fig. 3 is the A-A ' cut-open view of the planar light source device in embodiments of the invention.
Fig. 4 is the stereographic map near the rake of the light guide plate illustrated involved by prior art.
Fig. 5 is the figure for illustration of the impact caused due to the spacing of shortening light source in an embodiment of the present invention.
Fig. 6 is the stereographic map near the rake of the light guide plate illustrated in embodiments of the invention.
Fig. 7 is the curve map that fixed part surface of contact in embodiments of the invention and the contact area rate of fixed part and the relation of bonding force are shown.
Fig. 8 is the figure of the change of the cross sectional shape of the tongue and groove of the concavo-convex surface of contact illustrated in embodiments of the invention.
Fig. 9 is the stereographic map near the rake of the light guide plate illustrated in embodiments of the invention 2.
Figure 10 is the figure of the effect of the 1st directive property changing patterns for illustration of the rake in embodiments of the invention 2.
Figure 11 is the figure of the change of the cross sectional shape of the 1st directive property changing patterns of the rake illustrated in embodiments of the invention 2.
Figure 12 is the curve map of the relation between the angle of release of the pattern groove of the 1st directive property changing patterns illustrated in embodiments of the invention 2 and guide-lighting efficiency.
Figure 13 illustrates the figure overlooking relevant change to the 1st directive property changing patterns of the rake in embodiments of the invention 2.
Figure 14 be illustrate to the 1st directive property changing patterns of the rake in embodiments of the invention 2 overlook other relevant figure changed.
Figure 15 is the stereographic map near the rake of the light guide plate illustrated in embodiments of the invention 3.
Figure 16 is the vertical view of the light guide plate illustrated in embodiments of the invention 3 and the figure of side view.
Figure 17 be measure for illustration of the pitch angle of the terminal part of the light guide plate in embodiments of the invention 3 and pitch angle and HotSpot between the figure of relation.
Figure 18 is the figure measured for illustration of the HotSpot of the light guide plate in embodiments of the invention 3.
Figure 19 is the figure of the cross sectional shape of the 2nd directive property changing patterns for illustration of the light guide plate in embodiments of the invention 3.
Figure 20 is the figure of the cross sectional shape of the 2nd directive property changing patterns for illustration of the light guide plate in embodiments of the invention 3.
Figure 21 is the curve map of the relation between the angle of release of the pattern groove of the 2nd directive property changing patterns illustrated in embodiments of the invention 3 and HotSpot measure.
Figure 22 is the vertical view near the rake of the light guide plate illustrated in embodiments of the invention 3.
Figure 23 is the figure of the change of the cross sectional shape of the 2nd directive property changing patterns illustrated in embodiments of the invention 3.
Figure 24 is the figure that light source when to be relatively configured with multiple light source with the light entrance face of the light guide plate in embodiments of the invention 3 and light guide plate are shown.
Figure 25 is the figure of the relation of the 1st directive property changing patterns of the rake illustrated in embodiments of the invention 3 and the 2nd directive property changing patterns of terminal part.
Figure 26 is the figure of the change of the shape of the light-emitting face of the light guide plate illustrated in embodiments of the invention 3.
Figure 27 is the figure of change of inclined configuration of the upper end of the light entrance face illustrated in embodiments of the invention 3, rake, the structure of terminal part and the 1st directive property changing patterns, the 2nd directive property changing patterns.
Figure 28 is the figure of the electronic equipment illustrated in embodiments of the invention.
Label declaration
Upper end 10h fixed part surface of contact 10j concavo-convex surface of contact 10k terminal part 11 light source 12 flexible printed-circuit board 13 framework 13a teat 16 diffusion sheet 17a, 17b prismatic lens 18 anti-dazzling screen 20 the 1st directive property changing patterns 22 the 2nd directive property changing patterns of 1 planar light source device 10 light guide plate 10a main part 10b light introducing section 10d light-emitting face 10e light entrance face 10f rake 10g light entrance face
Embodiment
Below, with reference to the accompanying drawings embodiments of the present invention are described.In addition, the embodiment below illustrated only represents implements an example of the present invention, and is not limited to following explanation concrete structure of the present invention.
< embodiment 1>
(structure of liquid crystal indicator)
Fig. 1 is the stereographic map of the structure of the liquid crystal indicator of display device one example exemplified as the present embodiment.As shown in Figure 1, the liquid crystal indicator of the present embodiment possesses the planar light source device 1 configured as backlight (backlight) and the liquid crystal panel 2 accepting the light penetrated from planar light source device 1.Liquid crystal panel 2 is that the liquid crystal applied voltages by enclosing being clamped by glass plate makes the transmitance increase and decrease etc. of light show the display panel of picture.In addition, even if below in an example, liquid crystal indicator is formed similarly.In addition, in following record, sometimes liquid crystal panel 2 side in the planar light source device 1 of Fig. 1 is illustrated embodiment as upside, using its opposition side as downside.
(structure of planar light source device 1)
Fig. 2 is the stereographic map of the structure of the planar light source device 1 illustrating present embodiment.Planar light source device 1 in the present embodiment possesses light guide plate 10, is provided with multiple light sources 11, flexible printed-circuit board (following, to be also expressed as " FPC ") 12, framework 13 and fixed part 14.In addition, planar light source device 1 has the reflector plate 15 configured in the lower face side of light guide plate 10.In addition, planar light source device 1 have stack gradually in the upper surface side of light guide plate 10 diffusion sheet 16, prismatic lens 17a, 17b and anti-dazzling screen 18.
Light guide plate 10 is roughly tabular, comes shaping by the light transmission such as polycarbonate resin or plexiglass raw material.The face of the upside of light guide plate 10 becomes the light-emitting face of light injection.Light guide plate 10 utilizes total reflection that the light imported in light guide plate 10 from light source 11 is conducted to light-emitting face, makes light-emitting face entirety carry out luminescence equably.In light guide plate 10, the side of the light-emitting area subtend of light source 11 is provided with the incident light entrance face from the light of light source 11.
Light source 11 is the LED light sources from fluorescence portion (example of " light out part ") injection white light, but also can adopt the LED light source beyond white or the light source beyond LED light source.Its lead frame (not shown) engages with the pad of FPC12, accepts the power supply from FPC12 and is driven.FPC12 is the following circuit board formed: flexible insulativity film and matrix material arrange wiring by conductor foil and the coverlay of the bonding insulativity film as protecting from the teeth outwards having.On FPC12, multiple light source 11 is installed as row at certain intervals.
Framework 13 is the parts of the frame-shaped having opening and be made up of four limits.Framework 13 comes shaping by the polycarbonate resin containing titanium dioxide etc.Framework 13 is embedded with light guide plate 10, and the inner peripheral surface of framework 13 surrounds the side of the outer peripheral face forming light guide plate 10.Framework 13 has high reflectance, and the mode of not leaking from the outer peripheral face of light guide plate 10 according to the light made in light guide plate 10 reflects light.At framework 13 while be provided with the resettlement section of collecting light source 11, resettlement section is provided with reflection from the reflecting wall of the light of light source 11.
Fixed part 14 is configured on lower surface of FPC12 etc., is fixed FPC12, framework 13 and light guide plate 10.The double-faced adhesive tape of fixed part 14 to be such as upper and lower surface be adhesive surface, but be not limited only to double-faced adhesive tape.The adhesive strip beyond double-faced adhesive tape, bonding agent or cementing agent can also be utilized.Reflector plate 15 is the level and smooth sheets be made up of the high white resin sheet of reflectivity or metal forming etc., and the mode of not leaking from the downside of light guide plate 10 according to the light made in light guide plate 10 reflects light.Diffusion sheet 16 is translucent resin films, makes the light diffusion sent from the exiting surface of light guide plate 10 expand the directional property of light.Prismatic lens 17a and 17b has the transparent resin film forming the specular fine pattern of triangular prism at upper surface, assembles the light spread via diffusion sheet 16, makes to rise from brightness during upper surface side sightingpiston light supply apparatus 1.Anti-dazzling screen 18 is bonding sheets that upper and lower surface becomes the black of adhesive surface.Anti-dazzling screen 18 becomes margo frontalis shape, suppresses light to spill.
Fig. 3 is the cut-open view of the planar light source device 1 of the present embodiment.Fig. 3 illustrates the A-A ' cross section (with reference to Fig. 2) of planar light source device 1.In figure 3, at the upper surface side of light guide plate 10 stacked diffusion sheet 16, prismatic lens 17a and 17b.The FPC12 being provided with light source 11 is configured in the upside of light guide plate 10.Anti-dazzling screen 18 covers light source 11 or FPC12 from upside.Reflector plate 15 is overlapped on the surface of the downside of light guide plate 10.In addition, in the following description, sometimes towards Fig. 3 paper and the direction that the light that namely right side is penetrated from light source 11 is advanced being set to front side, its opposition side being set to rear side, paper inboard being set to left side, being described being set to right side on front side of paper face.
In figure 3, light guide plate 10 is provided with the light introducing section 10b of the large wedge shape of Thickness Ratio light guide plate main body portion 10a in the end of light guide plate main body portion 10a of the tabular defining uniform thickness.Be formed with multiple small optical design 10c at the lower surface of light guide plate main body portion 10a, the upper surface of light guide plate main body portion 10a becomes light-emitting face 10d.Light introducing section 10b has the end 10g of the light entrance face 10e for being taken into the light from light source 11 and the rake 10f as the dip plane be connected with light-emitting face 10d.Rake 10f tilts from the end 10g of light entrance face 10e to the mode of light-emitting face 10d step-down with height.
Then, the light introducing section 10b of Fig. 4 to existing light guide plate 10 is adopted to be illustrated.As shown in Figure 4, the light introducing section 10b of existing light guide plate 10 is being provided with on the position between multiple light sources 11, be provided with fixed part surface of contact 10h, this fixed part surface of contact 10h is the surface level that the mode of flatly cutting rake 10f with the midway in dip plane is formed.Jump height between fixed part surface of contact 10h and the end 10g of light entrance face 10e is set as the size slightly less than the thickness of fixed part 14, thus the thickness of fixed part 14 can be absorbed and flatly fix FPC12 relative to the light-emitting face 10d of light guide plate 10.Thus, can according to the mode making its light-emitting area parallel with the light entrance face 10e of light guide plate 11 relatively fixed light source 11.In addition, the size of the left and right directions of fixed part surface of contact 10h is formed as not hindering the light that penetrates from light source 11 to advance such size to light guide plate main part 10a.
Here, as mentioned above, in recent years, shorten the spacing of the light source 11 carried on planar light source device 1, carry more light source 11 and the demand improving brightness uprises.In response to this demand, as shown in Figure 5, the spacing between light source 11 and adjacent light source 11 is shortened, fixed part surface of contact 10h is in the narrowed width of left and right directions.Therefore the sufficient bounding force that the contact area sometimes between fixed part 14 and fixed part surface of contact 10h reduces and can not get for fixing FPC12 or bonding force.
Therefore, in the present embodiment, as shown in Figure 6, become concavo-convex surface of contact 10j by concaveconvex shape additional on fixed part surface of contact 10h, the bond area between fixed part 14 is increased.Thus, when becoming concavo-convex surface of contact 10j when concaveconvex shape additional on fixed part surface of contact 10h and the bond area between the light guide plate 10 of fixed part 14 increased, as shown in Figure 7, the bonding force increasing fixed part 14 pro rata can be similar to increased contact area.
Here, when thickness higher than the bonding coat of fixed part 14 of the height of concaveconvex shape, likely bond area reduces and bonding force reduces on the contrary.Therefore, the height of concaveconvex shape needs the thickness lower than the bonding coat of fixed part 14.Thus, when supposing to adopt thickness to be about 100 μm general fixed part 14, as long as make the height of concaveconvex shape become such as less than 30 μm, just contact area can be increased well.
In addition, the concaveconvex shape in concavo-convex surface of contact 10j can become as shown in Figure 6 such as along the tongue and groove that the fore-and-aft direction of light guide plate 10 is arranged.In addition, the cross sectional shape of this tongue and groove can become V-type as shown in Figure 8 or mountain type, curve or wave mode, V groove side at polygon, the rectangle or trapezoidal of bent halfway.In addition, the cross section of tongue and groove can not be symmetrical relative to groove center, such as, also can be the asymmetrical V-type groove in left and right.In addition, although not shown, the concaveconvex shape but in concavo-convex surface of contact 10j also can be the tongue and groove arranged along left and right directions or other direction of light guide plate 10.In addition, can not also be tongue and groove, but the shape of discrete projection or pit dispersion or uneven surface shape.
< embodiment 2>
Then, embodiments of the invention 2 are described.Following such example is described in the present embodiment: the pattern being provided with the directive property for controlling the light from light source from light entrance face incidence on the rake of light guide plate, concavo-convex surface of contact also arranges same pattern as tongue and groove.
Fig. 9 illustrates the stereographic map near the rake 10f of the light guide plate 10 of the present embodiment.In the present embodiment, such as, at rake 10f at least with the 1st directive property changing patterns 20 of directive property being formed with the light expanded to the left and right from light source incidence in the region of dotted line.1st directive property changing patterns 20 is for suppressing from light entrance face 10e to the light of light guide plate 10 incidence, not carrying out reflecting via rake 10f and be through the amount of the light that rake 10f externally leaks.In addition, the 1st directive property changing patterns 20, when observing from the upside of light guide plate 10, is formed as each pattern parallel on the fore-and-aft direction of light guide plate 10.
In the present embodiment, the tongue and groove in concavo-convex surface of contact 10j has the cross sectional shape same with the 1st directive property changing patterns 20.Therefore, when processing the shaping forming model of light guide plate 10, identical instrument can be utilized to process tongue and groove in concavo-convex surface of contact 10j and the 1st directive property changing patterns 20 continuously, the productivity of light guide plate 10 can be improved.In addition, according to the effect of the 1st directive property changing patterns 20, the guide-lighting efficiency of light guide plate 10 can be improved.This external above-mentioned in, the pattern in the 1st directive property changing patterns 20 of the tongue and groove preferred angled portion 10f on concavo-convex surface of contact 10j is consistent with crest line.Thus, light guide plate 10 shaping forming model add man-hour, can tongue and groove more reliably in the concavo-convex surface of contact 10j of Continuous maching and the 1st directive property changing patterns 20, can further improve the productivity of light guide plate 10.
(cross sectional shape of the 1st directive property changing patterns of rake)
Here, the cross sectional shape of the 1st directive property changing patterns in rake 10f is described in detail.Figure 10 is the figure observing light guide plate 10 from rear side (behind of light source 11).In addition as shown in Figure 10, the cross sectional shape of the 1st directive property changing patterns 20 of the rake 10f in the present embodiment is the V-type groove of the fore-and-aft direction along light guide plate 10.Further, the pattern of V-type groove is not the pattern with symmetrical shape, but has the region of asymmetrical cross sectional shape at least partially.Here, what utilize single dotted broken line to represent is luminescent center by light source 11 and the plane vertical with the light entrance face 10e of light guide plate 10 and light-emitting face 10d.
When the cross section that observation is as described above parallel with light entrance face 10e, the major part or the whole pattern grooves that form directive property changing patterns 20 have relative to the asymmetrical shape in groove center left and right.That is, the pattern inclined-plane 20a linking certain crest line (maximal point in cross section) in pattern and a valley line (minimal point in cross section) adjacent with this crest line and the pattern inclined-plane 20b (these pattern inclined-planes form the side of adjacent V-type groove) linking this crest line and another valley line (minimal point in cross section) adjacent with this crest line about by this crest line and the straight line vertical with light-emitting face 10d to become left and right asymmetric.
In addition, at the center from light source 11 towards in the region in left side, when setting up normal N (not shown) from the interior of light guide plate 10 on each pattern inclined-plane 20a, 20b, normal N is greater than the banner of the pattern inclined-plane 20a that normal N tilts to the opposition side of light source center to the banner that light source center rolls oblique pattern inclined-plane 20b.Equally, even if from light source center towards in the region on right side, normal N is greater than the banner of the pattern inclined-plane 20a that normal N tilts to the opposition side of light source center to the banner that light source center rolls oblique pattern inclined-plane 20b.
As a result, the light penetrated from the center of light source 11 to tilted direction is narrow compared with the situation of symmetrical 1st directive property changing patterns with the area of the pattern inclined-plane 20a close to vertical angle incidence and pattern groove, thus light is difficult to leak from pattern inclined-plane 20a.In addition, the pitch angle of the pattern inclined-plane 20a tilted to the opposition side of light source center with normal N becomes greatly, compared with the symmetrical situation of pattern groove of the 1st directive property changing patterns, incident angle to the light of pattern inclined-plane 20a incidence becomes large, so light is difficult to leak from pattern inclined-plane 20a.As a result, the leakage of the light from rake 10f can be suppressed, the guide-lighting efficiency of light guide plate 10 is improved.
In addition, in the 1st directive property changing patterns 20, the cross sectional shape of pattern groove can be made to change according to light source center distance apart.Various pattern is there is in such mode.Such as, in the rake 10f shown in (A) of Figure 11, the angle of release W of pattern groove diminishes gradually along with leaving light source center.In the rake 10f shown in Figure 11 (B), the angle of release W of pattern groove becomes large along with leaving light source center gradually.(C) of Figure 11 be not completely V-type groove and have flexure plane pattern groove arrangement the 1st directive property changing patterns 20, the bending status of pattern groove gradually changes along with leaving light source center.
(scope of drift angle)
Figure 12 illustrates the curve map by the relation between the angle of release W on the summit in the 1st directive property changing patterns 20 that multiple V-type groove is formed (angle of the side formation of adjacent V-type groove) and guide-lighting efficiency.The longitudinal axis of Figure 12 represents makes the guide-lighting efficiency of light guide plate become 100% when arranging symmetrical identical pattern elements.According to Figure 12, guide-lighting most effective when angle of release W is about 120 °, if angle of release W is 57 °≤scope of W≤145 °, guide-lighting efficiency just improves than existing situation.Thus, the angle of release W on the summit preferably in the 1st directive property changing patterns 20 is similar to the value of 120 °.
(the various forms of the 1st directive property changing patterns)
Then, the change of the form of the 1st directive property changing patterns 20 in overlooking is described.(A) ~ (C) of Figure 13 and (A) ~ (C) of Figure 14 is the summary vertical view of the various forms representing the 1st directive property changing patterns 20 and concavo-convex surface of contact 10j.When observing above light guide plate 10, the 1st directive property changing patterns 20 can form various forms as shown in the figure.In the form shown in (A) of Figure 13, the lower end from the midway of the dip plane of rake 10f to rake 10f and the boundary member of rake 10f and light-emitting face 10d form the 1st directive property changing patterns 20.Further, the two ends, left and right in the region of formation the 1st directive property changing patterns 20 that do not have mainly in rake 10f form concavo-convex surface of contact 10j.
In the form shown in (B) of Figure 13, at formation on the whole the 1st directive property changing patterns 20 of rake 10f.Further, become 0 degree (level) by the pitch angle of the part making rake 10f and form concavo-convex surface of contact 10j.In the form shown in (C) of Figure 13, only be positioned at light source 11 front rake 10f central portion formed the 1st directive property changing patterns 20, form concavo-convex surface of contact 10j in the end in the region of formation the 1st directive property changing patterns 20 that do not have of rake about 10f.
In the form shown in (A) of Figure 14, form the 1st directive property changing patterns 20, the lower edge of rake 10f from upper observation with convex flexure or bending.Further, become 0 degree (level) by the pitch angle of the part making rake 10f, form concavo-convex surface of contact 10j.In addition, in form before, 1st directive property changing patterns 20 is when observing from the upside of light guide plate 10, each pattern is formed as parallel at the fore-and-aft direction of light guide plate 10, but in the form shown in (B) of Figure 14, the pattern groove of the 1st directive property changing patterns 20 is not parallel, and with radial arrangement.Further, become 0 degree (level) by the pitch angle of the part making rake 10f, form concavo-convex surface of contact 10j, tongue and groove is still with radial arrangement.
In addition, the pattern groove that the 1st directive property changing patterns 20 shown in (C) of Figure 14 is bent by zigzag is formed.Further, become 0 degree (level) by the pitch angle of the part making rake 10f, form concavo-convex surface of contact 10j, the pattern groove that tongue and groove is still bent by zigzag is formed.
< embodiment 3>
Then, embodiments of the invention 3 are described.In the present embodiment, the 1st directive property changing patterns is set on rake identically with embodiment 2, and the same tongue and groove of the 1st directive property changing patterns is set on concavo-convex surface of contact.Further, between the rake being provided with the 1st directive property changing patterns and light-emitting face, pitch angle is also provided with different from rake and form the terminal part of the 2nd directive property changing patterns.
Figure 15 illustrates the stereographic map near the rake 10f of the light guide plate 10 of the present embodiment.In the present embodiment, rake 10f is formed with the 1st directive property changing patterns 20 making to expand from about the directive property of the light of light source incidence.1st directive property changing patterns 20 with illustrate in example 2 identical.Further, between rake 10f and light-emitting face 10d, form the 2nd directive property changing patterns 22, and be provided with the terminal part 10k making pitch angle be less than rake 10f.In addition, in the same manner as the 1st directive property changing patterns 20, the 2nd directive property changing patterns 22, when observing from the upside of light guide plate 10, the fore-and-aft direction of light guide plate 10 is formed as make each pattern parallel.In addition, here, the dip plane in terminal part 10k is equivalent to the second dip plane.
This terminal part 10k plays following such effect: utilize the 1st directive property changing patterns 20 in rake 10f to improve the guide-lighting efficiency of the light from light entrance face 10e incidence, then also utilizes the 2nd directive property changing patterns 22 formed in the region in the drawings shown in dotted line that the distribution of the light of direct light exit facet 10d in light guide plate 10 is become evenly.
Figure 16 illustrates to have concavo-convex surface of contact 10j, rake 10f, the 1st directive property changing patterns 20, the concrete vertical view of light guide plate 10 of terminal part 10k and the 2nd directive property changing patterns 22 and side view in the present embodiment.The part corresponding with light source 11 that vertical view shown in Figure 16 is only extracted out in light guide plate 10 is recorded.That is, the light guide plate 10 in the present embodiment configures with 4.7mm interval the scope that multiple light source 11, Figure 16 illustrates the width 4.7mm centered by a light source 11.
In the vertical view of Figure 16, the LED as light source 11 has the opening of 2mm.Further, the two ends, left and right of the rake 10f in the region of width 4.7mm are provided with concavo-convex contact site 10j.In addition, about the fore-and-aft direction of light guide plate 10, from light entrance face 10e to front side until the scope of 1mm becomes rake 10f.The tiltangleθ f with respect to the horizontal plane of this rake 10f is 9 ° ~ 10 °.This rake 10f is formed as described above the 1st directive property changing patterns 20 (utilizing the scope that the corner of solid line represents).
In addition, the scope from light entrance face 10e to 1mm to 1.5mm becomes terminal part 10k.This terminal part 10k forms the 2nd directive property changing patterns 22 (utilizing the scope that the corner of dotted line represents).In addition, the tiltangleθ k of terminal part 10k is 1.5 ° relative to horizontal line.
In addition, in the present embodiment, light-emitting face 10d (viewing area) is become from the scope of the front side of light entrance face 10e to 2.5mm.In addition, in the present embodiment, the height of light entrance face 10e is 0.4mm, and the height of light-emitting face 10d (viewing area) is 0.23mm.In addition, this light-emitting face 10d forms biconvex lens pattern (lenticularpattern) along the fore-and-aft direction of light guide plate 10.In addition, the light guide plate 10 in the present embodiment is formed by polycarbonate, and refractive index is 1.59.
(optimal value at the pitch angle of terminal part)
In above-mentioned, although the tiltangleθ k of terminal part 10k is 1.5 °, the tiltangleθ k of terminal part 10k is non-essential is 1.5 °.Below, the condition of the tiltangleθ k of terminal part 10k is described.(A) of Figure 17 illustrates the tiltangleθ f of rake 10f and the tiltangleθ k of terminal part 10k, and (B) of Figure 17 illustrate represent tiltangleθ k and the HotSpot of terminal part 10k measure between the curve map of relation.Transverse axis in (B) of Figure 17 is θ k, and the longitudinal axis is HotSpot (focus) amount.
Here, Figure 18 is adopted first to illustrate that HotSpot measures.Figure 18 is the vertical view of light guide plate 10, the figure shows how to distribute on light-emitting face 10d from the light of light source 11 incidence, namely from the light of light source 11 incidence in viewing area how by visual identity.(A) of Figure 18 illustrates the example of HotSpot amount comparatively large (poor), and (B) of Figure 18 illustrates the example of HotSpot amount less (good).
(A) that observe Figure 18 is known, and especially in the example of HotSpot amount comparatively large (poor), the end of light source 11 side in the viewing area of light guide plate 10 shows bright portion and dark portion clearly.Further, HotSpot amount is by the amount of the light quantity in the bright portion in the end of light source 11 side of viewing area divided by the light quantity gained of dark portion as Suo Shi formula (1).
The light quantity (1) of the light quantity ÷ dark portion in the bright portion in light source side end of HotSpot amount=viewing area
In addition, as shown in (B) of Figure 18, the measurement range of light quantity during detection HotSpot amount is that the fore-and-aft direction of the light guide plate 10 in the end of light source 11 side of viewing area is D0, left and right directions is the region of W0.Here, be D0=1mm in the present embodiment.In addition, W0 is determined by following formula:
W0=(arriving distance × tan (arcsin (the refractive index n of 1 ÷ light guide plate))+light source luminescent amplitude/2 of viewing area) (2).
Wherein, make the spacing of light source 11 when less, become the spacing of light source 11.When arrive the distance=2.5mm of viewing area, the width=2mm of light source 11, light guide plate refractive index n=1.59 (polycarbonate) time, become and evaluate width W 0≤± 3mm.
Turn back to the explanation of Figure 17.As shown in (B) of Figure 17, HotSpot amount becomes minimum value when the tiltangleθ k of terminal part 10k is 1.5 °, then, increases and become large along with tiltangleθ k.In addition, in existing light guide plate, HotSpot amount mostly represents the value of more than 2, as long as HotSpot amount is less than 1.5, just thinks the unevenness can improving light and shade fully.Can be described as thus, the tiltangleθ k of preferred terminal portion 10k becomes less than 3.5 °, preferably becomes 1.5 ° further.
In addition, according to the result of study of inventor, by meeting following condition, HotSpot amount can be suppressed for fully little value:
(1) allowable angle of inclination of the average slope angle < rake of terminal part
(2) the average slope angle <3.5 ° of terminal part
(3) the height H k< (the total height H fk of rake and terminal part)/3 of terminal part.
Preferably the size relationship of rake 10f and terminal part 10k is determined the condition for meeting above-mentioned (1) ~ (3).
(cross sectional shape of the 2nd directive property changing patterns of terminal part)
Then, the cross sectional shape of the 2nd directive property changing patterns 22 in terminal part 10k is described.As shown in figure 19, the 2nd directive property changing patterns 22 in the terminal part 10k of the present embodiment is V-type grooves of the fore-and-aft direction along light guide plate 10.Further, the cross sectional shape of V-type groove is not have the shape relative to the symmetrical shape of groove center, but at least partially, there is the region had relative to the asymmetrical cross sectional shape in groove center left and right.What in Figure 19, utilize single dotted broken line to represent is luminescent center by light source 11 and the plane vertical with the light entrance face 10e of light guide plate 10 and light-emitting face 10d.
In the light guide plate 10 of the present embodiment, the major part or the whole pattern groove (V-type groove) that form the 2nd directive property changing patterns 22 have as mentioned above relative to the asymmetrical shape in groove center left and right.That is, the pattern inclined-plane 22a linking certain crest line (maximal point in cross section) and a valley line (minimal point in cross section) adjacent with this crest line and the pattern inclined-plane 22b linking this crest line and another valley line (minimal point in cross section) adjacent with this crest line about by this crest line and the straight line vertical with light-emitting face 10d to become left and right asymmetric.But, a part of pattern groove (such as, being positioned at the pattern groove of the position of light source center) can be symmetrical.
In addition, from in the region in left side to figure, the center of light source 11, when setting up normal N from the interior of light guide plate 10 on each pattern inclined-plane 22a, 22b, normal N rolls mean value (mean value in the left field of the light source center of the banner D2 of each pattern inclined-plane 22b) from the banner D2 of oblique pattern inclined-plane 22b to light source center is greater than the mean value (mean value in the left field of the light source center of the banner D1 of each pattern inclined-plane 22a) of the banner D1 of the pattern inclined-plane 46a that normal N tilts to the opposition side of light source center.
Equally, even if from light source center region to the right, when setting up normal N from the interior of light guide plate 10 on each pattern inclined-plane 22a, 22b, normal N rolls mean value from the banner D2 of oblique pattern inclined-plane 22b to light source center is greater than the mean value of the banner D1 of the pattern inclined-plane 22a that normal N tilts to the opposition side of light source center.
In order to realize such form, as long as make normal N all be greater than the banner D1 of the pattern inclined-plane 22a that normal N tilts to the opposition side of light source center to the banner D2 that light source center rolls oblique pattern inclined-plane 22b or a part ofly identically both can in 2 adjacent pattern inclined-planes 22a, 22b.As long as that is, the groove of pattern at least partially in the 2nd directive property changing patterns 22 meet condition as follows both can: normal N is greater than the banner D1 of the pattern inclined-plane 22a that normal N tilts to the opposition side of light source center to the banner D2 that light source center rolls oblique pattern inclined-plane 22b.
As a result, the area making the opposition side to light source 11 center be reflected through the pattern groove 22b of the light of terminal part 10k and the central side to light source 11 be reflected through the pattern inclined-plane 22a of the light of terminal part 10k area compared with broaden.Thereby, it is possible to make broadly to be disperseed in the lateral direction by the light of terminal part 10k, the light quantity distribution in light-emitting face 10d can be made to become evenly.
(determination that the pitch angle based on the normal on pattern inclined-plane is carried out)
Here, following such situation is described: as shown in (A) of Figure 20 in above-mentioned, because normal N to be greater than the banner D1 of the pattern inclined-plane 22a that normal N tilts to the opposition side of light source center to the banner D2 that light source center rolls oblique pattern inclined-plane 22b, thus it is asymmetric to make the 2nd directive property changing patterns become left and right relative to groove center.Thereby, it is possible to make more efficiently to be disperseed in the lateral direction by the light of terminal part 10k, the light quantity distribution on light-emitting face 10d is become evenly.
Except the condition of the banner about above-mentioned such pattern inclined-plane 22a, 22b, as shown in (B) of Figure 20, the such condition of the mean value of the angle θ 2 of the normal N of pattern inclined-plane 22b can also be greater than relative to the mean value of the angle θ 1 of vertical line according to making the normal N of the pattern inclined-plane 22a in the 2nd directive property changing patterns 22, determine the condition of the left and right asymmetry of the 2nd directive property changing patterns.
In order to meet above-mentioned condition, as long as make the outside normal angle θ 1 of pattern inclined-plane 22a be greater than the inside normal angle θ 2 of pattern inclined-plane 22b or equally on a part of pattern inclined-plane both can on 2 pattern inclined-planes 22a, 22b of all of its neighbor.By meeting this condition, broadening compared with the area of the pattern inclined-plane 22a that the area that the opposition side to light source 11 center also can be made to be reflected through the pattern groove 22b of the light of terminal part 10k reflects with the central side to light source 11.Thereby, it is possible to make broadly to be disperseed in the lateral direction by the light of terminal part 10k, the light quantity distribution on light-emitting face 10d can be made to become evenly.
Then, the condition of the angle of release (drift angle) of pattern inclined-plane 22a, the 22b as shown in (C) of Figure 20 is described.
Figure 21 illustrate the angle of release W between pattern inclined-plane 22a, 22b in expression the 2nd directive property changing patterns 22 and above-mentioned HotSpot measure between the curve map of relation.According to Figure 21, as long as angle of release W is in the scope of 90 ° ~ 170 °, just HotSpot amount can be suppressed below 1.5.In addition we know, under angle of release W is 135 ° of situations, HotSpot amount display minimum value.
Here, as described above, the angle of release on the pattern inclined-plane of the guide-lighting efficiency in light guide plate 11 on the 1st directive property changing patterns 20 of rake 10f is top efficiency when being 120 °.Can be described as when combining and considering these conditions, the angle of release on the pattern inclined-plane in the 1st directive property changing patterns 20 being less than in rake 10f by making the angle of release on the pattern inclined-plane in the 2nd directive property changing patterns 22 of terminal part 10k, can make homogeneity both sides all optimizations of the guide-lighting efficiency in light guide plate 10 and the light quantity in light-emitting face 10d.
(pattern groove carries out situation about changing according to light source center distance apart)
2nd directive property changing patterns 22, in the left field and right side area of light source center, can make the cross sectional shape of each pattern groove change according to light source center distance apart.Figure 22 illustrates that the cross sectional shape of pattern groove carries out according to light source center distance apart the 2nd directive property changing patterns 22 that changes.
In fig. 22, utilize the 2nd directive property changing patterns of side between the 2nd directive property changing patterns 22 of light source center side and light source, the characteristic of pattern was changed with 2 stages.Specifically, in the left field and right side area of light source 11, the ratio of the banner D1 of the pattern inclined-plane 22a that the banner D2 rolling oblique pattern inclined-plane 22b about normal N to light source center and normal N tilt to the opposition side of light source center, between light source the region of side the 2nd directive property changing patterns 22 on than larger on the 2nd directive property changing patterns 22 in the region of light source center side.
Thus, compared with the region of light source center side, between light source side region in, can make more to be disperseed to the left and right significantly by the light of terminal part 10k.Thus, the light homogenising more reliably by light guide plate 10 can be made, the distribution reliably homogenising of the light quantity on light-emitting face 10d can be made.
In addition, also can utilize the 2nd directive property changing patterns of side between the 2nd directive property changing patterns 22 of light source center side and light source, make on the 2nd directive property changing patterns 22 in the region of ratio side between light source of the outside normal angle θ 1 of pattern inclined-plane 22a and the inside normal angle θ 2 of pattern inclined-plane 22b than larger on the 2nd directive property changing patterns 22 in the region of light source center side.
In addition, roll the area of oblique pattern inclined-plane 22b and the area ratio of observing the pattern inclined-plane 22a that the opposition side of normal N to light source center tilts from upside about observing normal N from upside to light source center, also can make on the 2nd directive property changing patterns 22 in the region of this area ratio side between light source than larger on the 2nd directive property changing patterns 22 in the region of light source center side.
(change of the pattern groove of terminal part)
Figure 23 illustrates the various changes in the cross section of the pattern groove of the 2nd directive property changing patterns 22.As the cross section of pattern groove, except V-type, such as can also for there is curve or the wave mode of front end R and making the inclined-plane of V-type groove at the polygon of flexure further halfway.In addition, also can be shape as follows: relative to light source center, angle of release W between pattern inclined-plane 22a and pattern inclined-plane 22b is kept necessarily, and pattern inclined-plane 22a and pattern inclined-plane 22b is along with leaving light source center and reverse direction to light source center tilts.
(possessing the planar light source device of multiple light source)
Then, the condition in the region forming terminal part 10k when possessing multiple light source 11 is described.Figure 24 be illustrate with the light entrance face 10e subtend of light guide plate 10 configure multiple light source 11 time light source 11 and the figure of light guide plate 10.In the case, using the centre of light source 11 and light source 11 as border, the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 is periodically formed with the cycle identical with the spacing P of light source 11.Such as, when the spacing of light source 32 described above is 4.7mm, the cycle of the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 is also 4.7mm.
When being arranged multiple light source 11 in this wise, there is the light of the light source 11 from both sides in the center section of light source 11 adjacent in the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 sometimes.Here, when the light of the light source 11 from both sides incides the somewhere of the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 simultaneously, be optimally designed to be difficult to produce light leakage or make the light quantity distribution in light-emitting face 10d become evenly more difficult for the light of two sides for the light of two sides.Thus, when the light of the light source 11 from both sides incides the somewhere of the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 simultaneously, reduce the guide-lighting efficiency of light guide plate 10 sometimes, or reduce the homogeneity of the light quantity distribution on light-emitting face 10d.
Therefore, preferably the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 is not substantially incided from the light of multiple light source 11.Here, following formula is expressed as from the incident angle Y entering into the light of light introducing section 10b by light entrance face 10e after light source 11 penetrates according to the rule of Fresnel:
Y＝arcsine(1/n)···(3)。
Wherein, n is the refractive index of light guide plate 10.Thus, the scope of expansion to the left and right for Y centered by light source center of the light in the 10b of light introducing section.
Light in the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 becomes to the broadening g of transverse direction according to above-mentioned formula 10:
g＝S·tanY≒S·Y＝S·arcsine(1/n)···(4)。
In order to make the light imported from light source center to Y-direction not enter adjacent region, if make this horizontal broadening g be less than the spacing P of light source 11 1/2 both can, therefore become:
g≤P/2····(5)。
Wherein, S is the distance from the end face (that is, light entrance face 10e) of light source 11 to the front end of the 2nd measured directive property changing patterns 22.Thus, the condition for making the light from 2 directions not arrive the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 becomes based on foregoing:
S≤P/〔2·arcsine(1/n)〕····(6)。
Therefore, when adopting multiple light source 11, as long as decide from the end face of light source 11 (namely in the mode of the condition meeting formula (6), light entrance face 10e) to the distance S of the front end of the 2nd measured directive property changing patterns 22, the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22 just optimally can be designed.That is, in the case, the light that can reduce in the rake 10f of light guide plate 10 leaks and improves guide-lighting efficiency, can also realize the homogenising of the light quantity in light-emitting face 10d.Such as, be P=4.7mm when making the spacing of light source 11, when making the refractive index of light guide plate 10 be n=1.59 (polycarbonate resin), as long as S is that about below 3.5mm both can.
(relation between the directive property changing patterns in rake and terminal part)
Figure 25 illustrates the relation between the 1st directive property changing patterns 20 of the rake 10f in the present embodiment and the 2nd directive property changing patterns 22 of terminal part 10k.As shown in Figure 25, in the present embodiment, the pattern groove of the 1st directive property changing patterns 20 is consistent with the crest line of the pattern groove of the 2nd directive property changing patterns 22.In addition, the crest line of the tongue and groove in concavo-convex surface of contact 10j is also consistent with the crest line of the pattern groove of the 1st directive property changing patterns 20 and the 2nd directive property changing patterns 22.Thus, to for making the shaping forming model of light guide plate 10 add man-hour, tongue and groove, the pattern groove of the 1st directive property changing patterns 20 and the pattern groove of the 2nd directive property changing patterns 22 in concavo-convex surface of contact 10j can be processed continuously simultaneously.As a result, the productivity of light guide plate 10 can be improved.
(change of the surface configuration of light-emitting face 10d)
Figure 26 illustrates the change of the surface configuration of the light-emitting face 10d of light guide plate 10.As the surface configuration of light-emitting face 10d, the lenticular shapes shown in (A) of such as Figure 26, the mirror shape as shown in (B) of Figure 26, the sleek shape as shown in (C) of Figure 26 also can be adopted.Here, so-called lenticular shapes is the lens of the semicircle column type that the multiple fore-and-aft direction along light guide plate 10 of arrangement is formed and the shape that formed.As far as possible so-called minute surface to get rid of concavo-convex and face that is that obtain.In addition, sleek refers to that the fore-and-aft direction along light guide plate 10 forms the surface state of the trickle processing trace stayed via the attrition process on surface.
(relation between horizontal part, rake, terminal part)
Figure 27 illustrates the change of inclined configuration of upper end 10g, the rake 10f of the light entrance face of the light guide plate 10 in the present embodiment, the formation of terminal part 10k and the 1st directive property changing patterns 20, the 2nd directive property changing patterns 22.In figure 27, with the region of the part that heavy line represents to be surface be minute surface, being the region being formed with the 1st directive property changing patterns 20 by the part that thick dotted line represents, is the region being formed with the 2nd directive property changing patterns 22 by the part that thick dashed line represents.In addition, the position applying arrow is the part forming bending point.
In the light guide plate 10 of (A) of Figure 27, the upper end 10g of light entrance face is the surface level on the surface with minute surface.Further, rake 10f is made up of clinoplane, is formed with the 1st directive property changing patterns 20 from the teeth outwards.In addition, the pitch angle clinoplane less than rake 10f and terminal part 10k are formed with the 2nd directive property changing patterns.
Then, in the light guide plate 10 of (B) of Figure 27, the upper end 10g of light entrance face is made up of surface level, and rake 10f is made up of clinoplane, and the upper end 10g and rake 10f of light entrance face are formed with the 1st directive property changing patterns 20.In addition, the pitch angle clinoplane less than rake 10f and terminal part 10k are formed with the 2nd directive property changing patterns.
In the light guide plate 10 of (C) of Figure 27, the upper end 10g of light entrance face is made up of surface level, and rake 10f is made up of clinoplane, and the upper end 10g and rake 10f of light entrance face are formed with the 1st directive property changing patterns 20.In addition, the pitch angle terminal part 10k less than rake 10f is the two benches plane changed in the mode diminished further at pitch angle, midway, forms the 2nd directive property changing patterns.
In the light guide plate 10 of (D) of Figure 27, the upper end 10g of light entrance face is made up of surface level, and rake 10f is made up of the two benches clinoplane changed to become large mode at pitch angle, midway, and the upper end 10g and rake 10f of light entrance face are formed with the 1st directive property changing patterns 20.In addition, be less than on the clinoplane of rake 10f and terminal part 10k at pitch angle and be formed with the 2nd directive property changing patterns.
In the light guide plate 10 of (E) of Figure 27, the upper end 10g of light entrance face is made up of surface level, and rake 10f is made up of the two benches clinoplane changed to become large mode at pitch angle, midway.Then, the plane of the upper end 10g of light entrance face and the upside of rake 10f is made up of minute surface, and the plane of the downside of rake 10f is formed the 1st directive property changing patterns 20.In addition, the pitch angle clinoplane less than rake 10f and terminal part 10k are formed with the 2nd directive property changing patterns.
(application)
As long as the planar light source device 1 illustrated in the above-described embodiments is applied to the liquid crystal indicator shown in Fig. 1 as backlight, just can provide that guide-lighting efficiency is high, brightness is high, light quantity distribution is even, the good and liquid crystal indicator that reliability is high of visual identity.
And such liquid crystal indicator can be equipped on various electronic equipment.As the electronic equipment possessing such liquid crystal indicator, except smart mobile phone as shown in figure 28, digital camera can also be illustrated, tablet terminal, e-book, wearable device, automobile navigation apparatus, electronic dictionary, electronic advertisement board etc.Thereby, it is possible to provide that brightness is high, the good and electronic equipment that reliability is high of visual identity.

Claims (12)

1. a planar light source device, possesses:
Tellite;
Light source, it is arranged on described tellite; And
Light guide plate, it imports the light sent by described light source from light entrance face, the light of this importing is guided to light-emitting face and penetrates with planar, the feature of this planar light source device is,
Described light guide plate is provided with rake, and this rake is arranged between described light entrance face and described light-emitting face, and its thickness reduces along with from light-emitting face side described in described light entrance face side direction,
The dip plane on the surface as described rake defines the notch with the face intersected with described light entrance face,
Described tellite is glued to the described notch of described rake, thus described light source is configured to relative with described light entrance face,
The face vertical with described light entrance face of described notch is formed the sag and swell that the contact area between the bonding coat making and be arranged on described tellite increases.
2. planar light source device according to claim 1, is characterized in that,
The height of described sag and swell is less than the thickness of described bonding coat.
3. planar light source device according to claim 2, is characterized in that,
The height of described sag and swell is less than 30 μm.
4. planar light source device as claimed in any of claims 1 to 3, is characterized in that,
Described sag and swell is that the groove be made up of the multiple groove being formed as extending on the direction vertical with described light entrance face constructs.
5. planar light source device according to claim 4, is characterized in that,
The V-type groove of to be the cross section in the direction parallel with described light entrance face the be V-shape of the groove in described groove structure.
6. the planar light source device according to claim 4 or 5, is characterized in that,
The cross section that described flute profile becomes the direction parallel with described light entrance face is that left and right is asymmetric about groove center.
7., according to the planar light source device in claim 4 to 6 described in any one, it is characterized in that,
The dip plane on the surface as described rake is provided with the 1st directive property changing patterns, 1st directive property changing patterns makes to be transformed to from the directive property broadening of light on the thickness direction of described light guide plate of described light entrance face incidence the directional property that the direction parallel towards the direction, face with this light guide plate tilt
Described 1st directive property changing patterns is configured to crest line and valley line and alternately repeats along the Width of described light guide plate.
8. planar light source device according to claim 7, is characterized in that,
Described sag and swell is consistent with the crest line in described 1st directive property changing patterns.
9. the planar light source device according to claim 7 or 8, is characterized in that,
Be provided with terminal part between described rake in described light guide plate and described light-emitting face, this terminal part has the second dip plane that pitch angle is relaxed than the dip plane as the surface of described rake,
Second dip plane of described terminal part is provided with the 2nd directive property changing patterns, 2nd directive property changing patterns disperses on the Width of described light guide plate by making the light guided by described rake, the light quantity of the light penetrated from described light-emitting face is become evenly
Described 2nd directive property changing patterns is configured to crest line and valley line and alternately repeats along the Width of described light guide plate.
10. planar light source device according to claim 9, is characterized in that,
Crest line in described sag and swell, described 1st directive property changing patterns and described 2nd directive property changing patterns is consistent.
11. 1 kinds of display device, is characterized in that possessing:
Planar light source device in claim 1 to 10 described in any one; And
Liquid crystal panel, it accepts the light penetrated from described planar light source device.
12. 1 kinds of electronic equipments, is characterized in that,
Possesses display device according to claim 11.
CN201510679259.8A 2014-10-21 2015-10-19 Planar light source device, display device and electronic equipment Active CN105527672B (en)

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