WO2010016497A1 - 面光源装置 - Google Patents
面光源装置 Download PDFInfo
- Publication number
- WO2010016497A1 WO2010016497A1 PCT/JP2009/063821 JP2009063821W WO2010016497A1 WO 2010016497 A1 WO2010016497 A1 WO 2010016497A1 JP 2009063821 W JP2009063821 W JP 2009063821W WO 2010016497 A1 WO2010016497 A1 WO 2010016497A1
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- WO
- WIPO (PCT)
- Prior art keywords
- guide plate
- light source
- light
- light guide
- reflector
- Prior art date
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Classifications
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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
- G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
- G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
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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
- G02B6/0013—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
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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
- G02B6/0055—Reflecting element, sheet or layer
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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
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
- G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
Definitions
- the present invention relates to a surface light source device, and in particular, is applied to a backlight of a transmissive LCD (LCD; liquid crystal display) or a transflective LCD, or an auxiliary light source (front light) of a reflective LCD.
- the present invention relates to a surface light source device.
- Patent Documents 1 to 3 As the surface light source device, one using a light guide plate is known (see, for example, Patent Documents 1 to 3).
- the light guide plate has at least one end in the length direction of the plate as the light guide plate entrance surface, and both ends in the thickness direction of the plate are the light guide plate exit surface and the light guide plate back surface, respectively, and light emitted from the light source is incident on the light guide plate. It is designed and manufactured so that it can be introduced from the surface and spread over almost the entire area of the light guide plate exit surface.
- the light that has entered the light guide plate from the light guide plate entrance surface is totally reflected by the light guide plate exit surface and the back surface of the light guide plate, so that it spreads over almost the entire area of the light guide plate exit surface and exits from the light guide plate exit surface.
- the surface light source device it is desirable that there is less light leakage from the back surface of the light guide plate, more light is emitted from the light guide plate exit surface, and the luminance distribution in the light guide plate exit surface is more uniform.
- the shape of the cross section perpendicular to the width direction of the light guide plate is a wedge shape
- the end surface of the wedge-shaped base side (the end portion side on the thick plate side) is the light guide plate incident surface. It is well known that it is advantageous that more light can be guided toward the wedge-shaped tip. For this reason, a surface light source device using a so-called wedge-shaped light guide plate in which the cross-sectional shape is a wedge shape is widely used.
- FIG. 16 is a cross-sectional view (light guide plate width direction orthogonal cross-sectional schematic view) schematically showing an example of a schematic configuration of a conventional surface light source device in a cross section orthogonal to the width direction of the light guide plate.
- FIG. 17 is a cross-sectional view (light guide plate width direction orthogonal cross-sectional schematic view) schematically showing another example of the schematic configuration of the conventional surface light source device in a cross section orthogonal to the width direction of the light guide plate.
- a CCFL cold cathode fluorescent lamp
- the CCFL 103 is opposed to the incident surface 102 of the light guide plate 101, and the CCFL 103 and the incident surface 102 are The inner surface is surrounded by a reflector 104 that is a reflective surface.
- the light emitted from the CCFL 103 in all directions is reflected by the reflector 104 and irradiated again to the CCFL 103, and is absorbed by the CCFL 103 and becomes a loss.
- the LED light emitting surface 206 of the LED package 205 is opposed to the incident surface 202 of the light guide plate 201.
- the LED light emitting surface 206 and the incident surface 202 are surrounded by a reflector 204 whose inner surface is a reflecting surface.
- the light reflected by the incident surface 2 of the light guide plate 201 is irradiated again on the LED light emitting surface 206 and absorbed by the LED light emitting surface 206, resulting in a loss.
- the present invention has been made in view of the above-described problems, and an object thereof is to provide a surface light source device capable of reducing light loss at the stage of light incidence from a light source to a light guide plate.
- the inventors have studied means for solving the above-mentioned problems, and as a result, have made the present invention described below.
- a surface light source device has at least one light source and at least one end in the length direction of the plate as a light guide plate incident surface, and both ends in the thickness direction of the plate.
- Light emitted from the light source as a light guide plate exit surface and a light guide plate back surface is introduced from the light guide plate entrance surface, and spreads and emits almost all over the light guide plate exit surface, and radiated from the light source
- the light guide plate entrance surface includes:
- the light source and the reflector have a concave surface portion having the same shape as an elliptical arc that forms part of a mother ellipse having two focal points, and the light source and the reflector are two of the mother ellipse including the concave surface portion as an elliptical arc. Focus on the light guide plate It is characterized by being
- the light source and the reflector form two focal points of a mother ellipse including the concave surface portion as an elliptical arc
- the light source and the reflector are incident on the concave surface portion from the light source on one line of the parallel two-track line.
- almost all of the light (primary reflected light) reflected by the concave surface portion is collected on the other line of the parallel two locus straight line.
- the reflector arranged on the other line can reflect almost all of the primary reflected light and irradiate the concave surface portion again.
- one concave surface portion is provided in a thickness direction of the plate, and at least a portion other than a peripheral portion of the light guide plate incident surface in the light guide plate incident surface, and the light guide plate It is preferable that the line of intersection with the surface perpendicular to the width direction is a single elliptical arc formed of the concave surface portion.
- the concave surface portion is provided at least in a portion other than the peripheral portion of the light guide plate incident surface on the light guide plate incident surface, and one concave surface portion is provided in the thickness direction of the light guide plate. ing.
- the arrangement of the light source and the reflector can be easily adjusted. At the same time, it is possible to improve the incident efficiency of light with respect to the incident surface of the light guide plate (the incident efficiency of light irradiated from the light source and the incident efficiency of reflected light by the reflector).
- a plurality of the concave surface portions are provided in the thickness direction of the plate, and at least a portion other than a peripheral portion of the light guide plate incident surface on the light guide plate incident surface, and the light guide plate.
- the line of intersection with the surface perpendicular to the width direction of the optical plate forms a connection shape of a plurality of elliptical arcs composed of the plurality of concave surface portions, and the light source and the reflector are provided in the thickness direction of the plate.
- each mother ellipse including each concave surface portion as an elliptical arc are respectively disposed on one and the other of two parallel locus lines formed by moving in the width direction of the light guide plate. Is preferred.
- the concave surface portion is provided at least in a portion other than the peripheral portion of the light guide plate incident surface on the light guide plate incident surface, and a plurality of the concave surface portions are provided in the thickness direction of the light guide plate.
- the arrangement of the light source and the reflector can be easily adjusted. At the same time, it is possible to improve the incident efficiency of light with respect to the incident surface of the light guide plate (the incident efficiency of light irradiated from the light source and the incident efficiency of reflected light by the reflector).
- the amount of light incident on the light guide plate can be increased.
- a surface light source device uses at least one light source and at least one end portion in the length direction of the plate as a light guide plate incident surface, and both end portions in the thickness direction of the plate.
- a light guide plate formed of the plate that introduces light emitted from the light source as the light guide plate exit surface and the light guide plate back surface from the light guide plate entrance surface, and spreads the light over almost the entire area of the light guide plate exit surface, and the light source.
- the light guide plate entrance surface having at least one reflector for further reflecting the light reflected from the light guide plate entrance surface among the light emitted from the light source and irradiating the light guide plate entrance surface
- the light guide plate entrance surface The line of intersection between the light incident surface of the light guide plate and the surface orthogonal to the width direction of the light guide plate has a curved or polygonal line shape, and the approximate curve of the line of intersection forms the two focal points between the light source and the reflector.
- the light source and the reflector are respectively provided on one and the other of two parallel locus lines formed by moving two focal points of the mother ellipse in the width direction of the light guide plate. It is characterized by being arranged.
- the condensing degree of the light (primary reflected light) which injects into the said concave-surface part from the light source, and was reflected by this concave-surface part is the said light source and reflector on the said light-guide plate incident surface.
- a concave part having the same shape as the elliptical arc forming a part of the mother ellipse as a bifocal point is provided, it is possible to obtain a sufficient optical loss reduction effect compared with the conventional case. it can.
- the light source can impart directivity to the light distribution and can irradiate most of the light source light to the incident surface 2. It is preferably at least one light source selected from the group consisting of LED light sources, multi-color LED light sources, organic EL light sources, and laser light sources.
- the reflecting surface of the reflector may have any one of a flat surface, a spherical surface, an elliptical cylindrical surface, and two or more connecting surfaces from the viewpoint of utilization efficiency of reflected light. preferable.
- the reflector has a reflection principal ray intersecting a locus straight line obtained by moving an intersection of the minor axis of the mother ellipse of the elliptical arc and the elliptical arc in the width direction of the light guide plate.
- the orientation is preferably adjusted.
- Ratio By adjusting the direction of the reflecting surface of the reflector as described above, the light irradiated on the light guide plate entrance surface among the light reflected by the reflector (particularly, the light irradiated on the concave portion). ) Ratio can be further increased. For this reason, the utilization factor of light source light further improves.
- the light source has a light irradiation direction such that a radiation principal ray thereof intersects a locus straight line obtained by moving the short axis of the elliptical arc and the minor axis of the elliptical arc in the width direction of the light guide plate. It is preferably adjusted.
- the ratio of the light emitted from the light source to the light guide plate incident surface is further increased. Can be increased. For this reason, the utilization factor of light source light further improves.
- an intersection line formed by the concave surface portion of the light guide plate entrance surface and a surface orthogonal to the thickness direction of the light guide plate intersects the cylindrical aspheric lens array and the cylinder axis orthogonal surface.
- the reflecting surface of the reflector is a convex surface having a shape similar to the concave portion of the light guide plate incident surface.
- the light utilization efficiency at the stage of light incidence from the light source to the light guide plate can be increased to the maximum.
- the surface light source device further includes a dichroic filter that selectively transmits only light having a specific wavelength out of wavelengths emitted from the light source and reflects light having a wavelength other than the specific wavelength
- the dichroic filter preferably has a concave surface and a convex back surface having the same shape as the concave surface portion of the light guide plate incident surface, and the convex back surface is attached in alignment with the concave surface portion of the light guide plate incident surface.
- the reflected light from the dichroic filter is condensed on the reflector in the same manner as the reflected light from the light guide plate incident surface when the dichroic filter is not provided, and is reflected by the reflector.
- the dichroic filter is irradiated again. Therefore, also in this case, it is possible to reduce the light loss at the light incident stage from the light source to the light guide plate.
- a plurality of the dichroic filters are provided in the width direction of the light guide plate, and adjacent dichroic filters have mutually different wavelengths to be transmitted, and the reflecting surface of the reflector
- the shape is the same as any one of the two-surface prism shape, the lens shape of the columnar aspheric lens, and the connection shape in the width direction of the light guide plate at an interval equal to or less than the pitch of the dichroic filter.
- a surface shape that repeats the shape is preferable.
- the shape is a repetitive shape of the prism double-surface connection shape, the repetitive shape of the lens shape of the columnar aspherical lens, and the double-surface connection shape of the prism at an interval equal to or less than the pitch of the dichroic filter It is preferable to have any one surface shape among the connection shapes in which the lens shape of the columnar aspherical lens is mixed.
- the ratio of the light that is irradiated from the dichroic filter to the reflector and reflected by the reflector returns to the same dichroic filter is reduced. For this reason, light loss is reduced and the utilization factor of the light source light is further improved.
- the surface light source device may selectively transmit only polarized light in one direction among wavelengths of light emitted from the light source and irradiate the incident surface of the light guide plate with light reflected by the polarizing element.
- a polarizing plate having a concave surface and a convex back surface having the same shape as the concave portion of the light guide plate entrance surface, The back surface is aligned with the concave portion of the light guide plate entrance surface and is attached to the light guide plate entrance surface, and the wide viewing angle quarter-wave plate is disposed on the reflective surface of the reflector. preferable.
- the surface light source device includes a polarizing element that selectively transmits only polarized light in one direction among wavelengths of light emitted from the light source and irradiates the incident surface of the light guide plate, and a quarter-wave plate
- the polarizing element further includes a concave surface having the same shape as the concave portion of the light guide plate entrance surface, and a convex back surface, the convex back surface being aligned with the concave portion of the light guide plate entrance surface, and It is preferable that the quarter-wave plate attached to the light incident surface is disposed on the reflection surface of the reflector.
- the reflected light from the polarizing element is condensed on the reflector in the same manner as the reflected light from the light guide plate incident surface of the light guide plate when the polarizing element is not provided.
- the polarization direction changes by 90 °
- the polarization direction Changes by 180 °.
- the polarization direction changes by 90 ° to become light having the same polarization state as the light source light, and is irradiated again to the polarizing element.
- the polarization axis of the light irradiated again on the polarization element is substantially equal to the polarization axis of the polarization element, and most of the light passes through the light guide plate.
- the surface light source device further includes a reflecting mirror facing the back surface of the light guide plate, and a surface facing the back surface of the light guide plate in the reflecting mirror is a reflecting surface having an area equal to or larger than the area of the back surface of the light guide plate. It is preferable.
- the light leaking from the back surface of the light guide plate can be reflected by the reflecting mirror and applied to the back surface of the light guide plate.
- the area of the reflecting surface of the reflecting mirror is larger than the area of the back surface of the light guide plate, the ratio of the light reflected from the reflecting mirror and irradiated to the back surface of the light guide plate out of the light leaking from the back surface of the light guide plate growing. Therefore, the utilization factor of light source light can be further improved.
- the light guide plate entrance surface includes a concave surface having the same shape as an elliptical arc forming a part of a mother ellipse having the light source and the reflector as two focal points.
- the light incident surface of the light guide plate is an elliptic arc of a part of a mother ellipse in which an intersection line between the light incident surface of the light guide plate and a surface perpendicular to the width direction of the light guide plate has the light source and the reflector as two focal points.
- Quasi-elliptical arc shape that is in a band region having a width of 20% or less of the major axis length of the mother ellipse with a center line as a center line and is connected to both ends in the length direction of the band region.
- the concave surface portion is provided.
- the light source and the reflector are respectively arranged on one and the other of two parallel locus lines formed by moving two focal points of the mother ellipse in the width direction of the light guide plate. Yes.
- the light source and the reflector form two focal points of the mother ellipse
- the concave surface portion forms an elliptical arc of the mother ellipse
- the light source on one line of the parallel two-trajectory straight line extends from the light source to the concave surface portion.
- Almost all of the incident light (primary reflected light) reflected by the concave surface portion is condensed on the other line of the parallel two-track line.
- the light source and the reflector form two focal points of the mother ellipse, the closer the concave surface portion is to the shape of the elliptical arc of the mother ellipse, the light reflected by the concave surface portion (primary reflected light) is The ratio of irradiation on the other line of the parallel two-track line increases.
- the concave surface portion is a pseudo elliptical arc-shaped concave surface portion approximated by the elliptical arc of the mother ellipse
- the concave surface portion is incident on the concave surface portion from a light source on one line of the parallel two locus straight line
- the light reflected by the concave surface portion is the other of the parallel two locus straight lines compared to the case where the light guide plate incident surface, the light source, and the reflector do not have the above-described relationship. It is easy to concentrate on the line.
- the loss of light incident from the light source to the light guide plate incident surface can be reduced as compared with the conventional case. For this reason, the utilization factor of light source light can be improved compared with the past.
- (A) is a perspective view which shows typically an example of schematic structure of the surface light source device concerning Embodiment 1 of this invention
- (b) is the light-guide plate entrance surface of the surface light source device shown to (a).
- In the surface light source device concerning Embodiment 1 of this invention it is sectional drawing which shows typically schematic structure of the light-guide plate entrance surface vicinity when a reflector is provided.
- (A) is a perspective view which shows an example of schematic structure of the surface light source device concerning Embodiment 2 of this invention
- (b) is the outline of the light-guide plate entrance plane vicinity of the surface light source device shown to (a). It is sectional drawing which shows a structure in a W direction orthogonal cross section
- (c) is sectional drawing which shows schematic structure of the light-guide plate entrance plane vicinity of the surface light source device shown to (a) in a T direction orthogonal cross section.
- (A) * (b) is a top view which shows typically the suitable example of the reflector shown in FIG. 12, respectively. It is a perspective view which shows typically schematic structure of the entrance plane vicinity in the surface light source device concerning Embodiment 5 of this invention. It is sectional drawing which shows typically schematic structure of the light-guide plate entrance plane vicinity of the other surface light source device concerning Embodiment 5 of this invention in a W direction orthogonal cross section. It is sectional drawing which shows typically the cross section orthogonal to the width direction of a light-guide plate in the conventional surface light source device. It is sectional drawing which shows typically the other example of schematic structure of the conventional surface light source device in the cross section orthogonal to the width direction of a light-guide plate.
- the surface light source device is a so-called sidelight type light source device in which a light source is provided on at least one end surface of the light guide plate.
- a light source is provided on at least one end surface of the light guide plate.
- the case where the light source is a point light source and the light source is provided on at least one end surface (lateral end portion) of the light guide plate will be described as an example.
- the present embodiment is not limited to this.
- FIG. 1A is a perspective view (three-dimensional schematic diagram) schematically showing an example of a schematic configuration of the surface light source device according to the present embodiment
- FIG. 1B is a diagram (a) of FIG. It is sectional drawing which shows typically schematic structure of the light-guide plate entrance plane vicinity of the surface light source device shown in FIG.
- the surface light source device includes a light guide plate 1, a point light source 13 (light source), and a reflector 14.
- the point light source 13 is provided to face one end portion (one end surface) of the light guide plate 1 in the length direction (hereinafter referred to as “L direction”).
- a plurality of point light sources 13 are arranged in the width direction of the light guide plate 1 (hereinafter referred to as “W direction”).
- Examples of the point light source 13 include an LED (light emitting diode) light source and a laser light source.
- Examples of the LED light source include a white LED light source, an RGB-LED light source, and a multi-color LED light source.
- a white LED light source emits white light from one LED chip by superimposing a plurality of lights having different wavelengths.
- a white LED light source although the light emitting element formed by combining blue LED and yellow light emission fluorescent substance is mentioned, for example, it is not limited to this.
- the RGB-LED light source is a light emitting element in which a red (R) LED, a green (G) LED, and a blue (B) LED are each mounted in one package.
- a multi-color LED is a light emitting element in which a plurality of types (for example, three types) of LEDs having different emission colors are mounted in a single package.
- At least one light source selected from the group consisting of these white LED light source, RGB-LED light source, multi-color LED light source, and laser light source can impart directivity to the light distribution. It is possible to irradiate most of the light source light onto the incident surface 2 and is particularly preferably used.
- the surface light source device emits light from the point light source 13 with the end portion (end surface) facing the point light source 13 in the light guide plate 1 as a light guide plate incident surface (hereinafter referred to as “incident surface” for short) 2. Light is introduced from the incident surface 2 into the light guide plate 1.
- T direction One end portion of the end portions (main surface, plate surface) in the thickness direction of the light guide plate 1 (hereinafter referred to as “T direction”) is referred to as a light guide plate exit surface (hereinafter referred to as “exit surface” for short). It functions as 7. That is, the T direction is a direction orthogonal to the exit surface 7. Note that the L direction, the W direction, and the T direction are orthogonal to each other.
- the light guide plate 1 causes light introduced from the incident surface 2 to exit (surface radiation) from the exit surface 7.
- the light guide plate 1 has one end portion in the L direction as the incident surface 2 and both end portions in the T direction as the exit surface 7 and the rear surface of the light guide plate (hereinafter referred to as “rear surface” for short) 8.
- the light emitted from 13 is introduced from the incident surface 2 and is designed and manufactured so as to be spread and emitted almost all over the emission surface 7.
- the light guide plate 1 is typically formed using a transparent resin material such as polycarbonate or polymethyl methacrylate.
- a transparent resin material such as polycarbonate or polymethyl methacrylate.
- the present embodiment is not limited to this.
- the reflector 14 further reflects and irradiates the incident surface 2 with the light reflected from the incident surface 2 out of the light emitted from the point light source 13.
- the reflecting surface 14 a of the reflector 14 faces the incident surface 2.
- the reflector 14 for example, a plate-like reflector, a film-like reflector, or the like can be used.
- the material of the reflector 14 is not particularly limited, and may be a regular reflection material or a diffuse reflection material. However, when the diffuse reflection material is used, the utilization factor of the light reflected by the diffuse reflection material and incident on the incident surface 2 is lower than that when the regular reflection material is used. For this reason, it is more preferable to use a regular reflection material.
- regular reflection material examples include metal materials such as silver and aluminum. Among these, silver is preferable because of its high reflectance (regular reflectance). There is also a method of further increasing the reflectance by laminating a dielectric multilayer film composed of a plurality of dielectric films on a metal material or the like.
- examples of the diffuse reflection material include white materials such as white plastic and white paint.
- the material of the reflector 14 is that a dielectric multilayer film is laminated on aluminum which is a regular reflective material, and the re-incidence rate of light to the incident surface 2 is the highest. Since it becomes high, it is preferable.
- the reflectance of the dielectric multilayer film coated on aluminum is 95 to 98%, which is higher than that of a single metal.
- the incident surface 2 of the light guide plate 1 has the same shape as an elliptical arc forming a part of a mother ellipse 31 having a point light source 13 and a reflector 14 as two focal points.
- the point light source 13 and the reflector 14 have two focal points of the mother ellipse 31 of the elliptic arc 10 (that is, an ellipse having the elliptic arc 10 as a part) indicated by a two-dot chain line (virtual line) in FIG.
- the light guide plate 1 is arranged on one and the other of parallel two-track lines (hereinafter referred to as “elliptical bifocal lines”) 11 and 12 that move in the W direction, which is the width direction of the light guide plate 1.
- the elliptical arc 10 (in this embodiment, the entire incident surface 2), which is an elliptical arc-shaped concave portion provided on the incident surface 2 of the light guide plate 1, is configured by an elliptical arc that forms part of the mother ellipse 31.
- the broken line indicates that the point light source 13 and the reflector 14 are two focal points of the mother ellipse 31 together with the light indicated by the alternate long and short dash line.
- the point light source 13 and the reflector 14 form two focal points of a mother ellipse 31 including the elliptical arc 10 (that is, a concave surface portion having an elliptical arc shape) as an elliptical arc.
- the elliptical arc 10 that is, a concave surface portion having an elliptical arc shape
- light incident on the elliptical arc 10 from the point light source 13 arranged on one of the elliptical bifocal lines 11 and 12 and reflected by the elliptical arc 10 hereinafter referred to as “primary”. Almost all of the reflected light ”is collected on the other elliptical bifocal line 12.
- the reflector 14 arranged on the elliptical bifocal line 11 can reflect almost all of the primary reflected light and irradiate the elliptical arc 10 (incident surface 2) again. Therefore, the loss (loss) of light at the stage of light incidence from the point light source 13 to the light guide plate 1 can be significantly reduced as compared with the conventional case.
- the point light source 13 and the reflector 14 may be exchanged with each other in whole or in part. Further, another reflection medium may be installed at a position outside the primary reflected light incident path to the reflector 14.
- the point light source 13, the reflector 14, and the incident surface 2 may be surrounded by a reflector 18 (reflection resistant, reflecting mirror).
- the reflector 18 may have a dome shape or another shape.
- a reflector similar to the reflector 104 shown in FIG. 16 and the reflector 204 shown in FIG. 17 can be used.
- the case where the light source is the point light source 13 has been described as an example.
- the present embodiment is not limited to this. It is not something.
- FIG. 3 is a perspective view (three-dimensional schematic diagram) schematically showing another example of the schematic configuration of the surface light source device according to the present embodiment.
- a surface emitting light source 15 may be used as the light source instead of the point light source 13 shown in FIGS.
- at least one end portion in the length direction of the light guide plate 1 is an incident surface 2, and a surface emitting light source 15 is provided along the incident surface 2.
- the same setting is made as when the point light source 13 is used as the light source. That is, it goes without saying that the point light source 13 can be replaced with the surface light source 15 in the above description and the description to be described later.
- an organic EL (EL) light source can be preferably used.
- the light distribution can be given directivity, and the incident surface 2 can be irradiated with most of the light source light.
- the light source used in the present embodiment is preferably at least one light source selected from the group consisting of a white LED light source, an RGB-LED light source, a multi-color LED light source, a laser light source, and an organic EL light source.
- a white LED light source an RGB-LED light source
- a multi-color LED light source a laser light source
- an organic EL light source a light source selected from the group consisting of a white LED light source, an RGB-LED light source, a multi-color LED light source, a laser light source, and an organic EL light source.
- the incident surface 2 of the light guide plate 1 has the point light source 13 and the reflector 14 as two focal points.
- the case of having an elliptical arc shape has been described as an example. However, the present embodiment is not limited to this.
- FIG. 4 is a cross-sectional view (cross-sectional schematic diagram) schematically showing a schematic configuration in the vicinity of the light guide plate entrance surface in another surface light source device according to the present embodiment.
- FIG. 5 is a perspective view (three-dimensional schematic diagram) schematically showing a schematic configuration in the vicinity of the light guide plate incident surface in still another surface light source device according to the present embodiment.
- the elliptical arc 10 extends in the T direction, which is the thickness direction of the light guide plate 1, on the incident surface 2, as shown in FIGS. Only one may be provided, or a plurality may be provided as shown in FIG.
- FIG. 4 illustrates the case where the point light source 13 is used as the light source
- FIG. 5 illustrates the case where the surface emitting light source 15 is used as the light source.
- the present embodiment is not limited thereto. is not. As described above, the point light source 13 and the surface light source 15 can be interchanged.
- the surface emitting light source 15 and the reflector 14 are each concave surface portions. Are provided opposite to each other.
- the elliptical arc 10 is arranged with respect to one elliptical arc 10 adjacent in the T direction.
- the surface emitting light source 15 and the reflector 14 are respectively placed on one and the other of the elliptical bifocal lines 11 and 12 formed by moving the two focal points of the mother ellipse 31 including the elliptical arc in the W direction which is the width direction of the light guide plate 1. Be placed.
- the light guide plate 1 focuses two focal points of the mother ellipse 31A including the elliptical arc 10A as an elliptical arc.
- the surface-emitting light source 15A and the reflector 14A are respectively arranged on one and the other of the elliptical bifocal lines 11A and 12A that are moved in the W direction, which is the width direction.
- the amount of light incident on the light guide plate 1 can be increased. it can.
- the light incident surface 2 of the light guide plate 1 has an entire surface of the light incident surface 2 formed in an elliptical arc shape as shown in FIGS. There is no need.
- At least a portion other than the peripheral portion of the incident surface 2 (most portion excluding the peripheral portion) in the incident surface 2 is single. It is preferably formed in an elliptical arc shape or a connecting shape of elliptical arcs.
- the line of intersection with the surface orthogonal to the direction has a connection shape of a plurality of elliptical arcs 10 composed of a plurality of concave surface portions (elliptical arcs 10).
- the incident surface 2 of the light guide plate 1 only needs to have the elliptical arc 10 in the region where the light emitted from the point light source 13 is incident and the region where the reflected light from the reflector 14 is irradiated, as described above. Further, the formation position and the number of the elliptical arcs 10 are not particularly limited.
- the incident surface 2 other than the peripheral portion of the incident surface 2, particularly at least a main portion (a major portion excluding the peripheral portion) of the incident surface 2 has an elliptical shape as described above.
- the arrangement of the light source and the reflector 14 can be easily adjusted, and the incident efficiency of light with respect to the incident surface 2 (incident efficiency of light emitted from the light source and incident efficiency of reflected light by the reflector 14) can be improved. be able to.
- the surface light source device at least the main part (most part excluding the peripheral part) of the incident surface 2 has a single elliptical arc shape or a connected shape of a plurality of elliptical arcs.
- the point light source 13 and the reflector 14 are connected to one of the elliptical bifocal lines 11 and 12 formed by moving the two focal points of the mother ellipse 31 of the elliptical arc 10 in the width direction of the light guide plate 1. It is preferable to arrange each on the other line.
- the case where the reflector 14 having the planar reflecting surface 14a is used as the reflector 14 is illustrated as an example.
- the shape of the reflecting surface 14a of the reflector 14 is not limited to this.
- the reflecting surface 14 a of the reflector 14 may have an elliptic cylindrical surface shape (convex surface shape, for example, a convex cylindrical shape extending along the incident surface 2).
- the reflecting surface 14a of the reflector 14 is preferably one of a flat surface, a spherical surface, and an elliptic cylindrical surface, or the same surface shape as two or more connecting surfaces from the viewpoint of utilization efficiency of reflected light. .
- the light reaching the reflector 14 is almost collected at one point. For this reason, even if the reflector 14 is spherical, for example, it is approximated to a plane when viewed from one point where light is condensed.
- the connecting surface is formed in a direction parallel to the W direction of the light guide plate 1.
- the reflector 14 having two or more connecting surfaces arranged in the arrangement place of the reflector 14 has the connecting surfaces so that the reflected light falls within the range irradiated to the corresponding elliptical arc 10. Is formed. Thereby, light can be reflected in a random direction toward the elliptical arc 10 as compared with the case where the reflecting surface 14a of the reflector 14 is a simple (that is, a single) plane, spherical surface, or elliptical cylindrical surface. it can. For this reason, reflected light can be more uniformly reflected on the incident surface 2.
- the direction of the reflector 14 and the light source will be described below with reference to FIGS.
- the point light source 13 will be described as an example of the light source, but the present embodiment is not limited to this.
- FIGS. 6 to 8 are cross-sectional views (cross-sectional schematic views) schematically showing a schematic configuration in the vicinity of the light guide plate entrance surface in still another surface light source device according to the embodiment of the present invention.
- the reflector 14 is such that the reflected principal ray 22 of the reflector 14 crosses the intersection P between the minor axis 16 of the mother ellipse 31 of the elliptical arc 10 and the elliptical arc 10 in the W direction. It is preferable that the direction of the reflecting surface 14a of the reflector 14 is adjusted so that it intersects with the locus straight line.
- the light irradiated on the incident surface 2 out of the light reflected by the reflector 14 (particularly, the light irradiated on the elliptical arc 10).
- the ratio of can be further increased. For this reason, the utilization factor of light source light (that is, light emitted from the point light source 13) is further improved.
- the point light source 13 has a radiant chief ray 23 formed by moving the intersection P between the minor axis 16 of the mother ellipse 31 of the elliptical arc 10 and the elliptical arc 10 in the W direction. It is preferable that the direction of the point light source 13 (light irradiation direction) is adjusted so that it intersects with.
- both of the reflector 14 and the point light source 13 are adjusted as described above rather than adjusting either one of them as described above. That is, the embodiment illustrated in FIG. 6 and the embodiment illustrated in FIG. 7 improve the utilization rate of the light source light when implemented in combination with each other as illustrated in FIG. 8 rather than individually. More preferable.
- the configuration shown in FIG. 9 is more preferable.
- FIG. 9 is a cross-sectional view (cross-sectional schematic diagram) schematically showing still another example of the schematic configuration of still another surface light source device according to the present embodiment in a cross section orthogonal to the W direction (cross section orthogonal to the W direction). ).
- the surface light source 15 is used as the light source.
- the present embodiment is not limited to this.
- the surface light source device shown in FIG. 9 has a configuration in which a reflecting mirror 28 is provided on the back surface 8 of the light guide plate 1.
- the reflecting mirror 28 reflects the light leaking from the back surface 8 of the light guide plate 1 and irradiates the back surface 8. Therefore, as described above, by attaching the reflecting mirror 28 to the back surface 8 of the light guide plate 1, the utilization factor of the light source light can be further improved.
- the reflecting mirror 28 preferably has a reflecting surface 28 a having an area equal to or larger than the area of the back surface 8 of the light guide plate 1, and is preferably disposed so that the reflecting surface 28 a faces the back surface 8 of the light guide plate 1.
- the area of the reflection surface 28a is smaller than the area of the back surface 8, the ratio of the light leaked from the back surface 8 reflected by the reflecting mirror 28 and irradiated on the back surface 8 is disadvantageous. is there.
- the area of the reflecting surface 28 a of the reflecting mirror 28 is larger than the area of the back surface 8, the light that is reflected by the reflecting mirror 28 and irradiates the back surface 8 out of the light leaking from the back surface 8. The proportion increases. Therefore, the area of the reflecting surface 28a of the reflecting mirror 28 is more preferably larger than the area of the back surface 8.
- the reflecting surface 28a of the reflecting mirror 28 is not a uniform planar shape, but the uneven surface shape, the light leaking from the back surface 8 of the light guide plate 1 is more randomly directed. It is preferable because it can be reflected and uniformly irradiated by the back surface 8 of the light guide plate 1.
- a wedge-shaped light guide plate in which the incident surface 2 is provided on the thick end side is described as an example of the light guide plate 1.
- the present embodiment is not limited to this.
- a flat light guide plate in which the emission surface 7 and the back surface 8 are parallel to each other can also be used.
- the light source and the reflector 14 are arranged so as to face both of these two incident surfaces 2.
- the light source only needs to be provided on at least one end surface (lateral end portion) of the light guide plate.
- one end of the flat light guide plate in the L direction may be the incident surface 2 and the opposite end may be the reflecting surface.
- the reflecting surface for example, a plate-like reflecting material, a film-like reflecting material or the like can be adhered and used.
- the material of the reflection surface is not particularly limited, and may be a regular reflection material or a diffuse reflection material.
- the specular reflection material include metal materials such as silver and aluminum as described above.
- examples of the diffuse reflection material include white materials such as white plastic and white paint.
- these reflective materials as the material of the reflective surface, since a high reflectance can be realized, it is preferable to form a metal material on the reflective surface shape portion by vacuum deposition or the like.
- the present embodiment the case where the point light source 13 is provided on one end surface (lateral end portion) of the light guide plate 1 will be described as an example. However, as described above, the present embodiment is not limited to this. It is not limited to.
- the incident surface 2 itself is formed in an elliptical arc shape, and only one elliptical arc 10 is provided in the W direction of the incident surface 2. The case is shown.
- the present invention is not limited to this.
- FIG. 10A is a perspective view (three-dimensional schematic diagram) showing an example of a schematic configuration of the surface light source device according to the present embodiment.
- 10B is a cross-sectional view orthogonal to the W direction that is the width direction of the light guide plate 1 (a cross section orthogonal to the W direction), in the vicinity of the light guide plate incident surface of the surface light source device shown in FIG. 10C is a cross-sectional view of the light source plate entrance surface of the surface light source device shown in FIG. 10A, in the T direction, which is the thickness direction of the light guide plate 1. It is sectional drawing shown by the cross section orthogonal to (T direction orthogonal cross section).
- the elliptical arc 10 of the incident surface 2 is a surface orthogonal to the T direction (T direction orthogonal surface).
- the intersecting line 17 has the same shape as the intersecting line shape between the cylindrical aspherical lens array and the cylinder axis orthogonal surface, and as shown in FIGS.
- the 14 reflecting surfaces 14 a have a convex shape similar to the concave surface portion (each elliptical arc 10) of the incident surface 2.
- the reflecting surface 14a of the reflector 14 has a convex surface shape similar to the concave surface portion (each elliptical arc 10) of the incident surface 2, the light reflected by the reflecting surface 14a of each reflector 14 is reflected.
- the ratio of the light applied to the incident surface 2 can be further increased.
- the surface light source device is provided with a plurality of elliptical arcs 10 in the W direction of the incident surface 2.
- the point light source 13 and the reflector 14 are elliptical bifocal lines 11 and 11 formed by moving two focal points of the mother ellipse 31 of each elliptical arc 10 in the W direction. 12 are arranged on one and the other lines, respectively. Accordingly, as shown in FIG. 1A, the reflector 14 is a single unit extending from one end portion in the W direction of the incident surface 2 to the other end portion along the elliptical bifocal line 12.
- One reflecting member can be used.
- FIG. 10 (a) particularly when a plurality of point light sources 13 are arranged on one of the elliptical bifocal lines 11 and 12 as the light source, (b) and (c) in FIG.
- the present embodiment the case where the point light source 13 is provided on one end surface (lateral end portion) of the light guide plate 1 will be described as an example. However, as described above, the present embodiment is not limited to this. It is not limited to.
- FIG. 11 is a cross-sectional view (cross-sectional schematic diagram) schematically showing a schematic configuration in the vicinity of the light guide plate entrance surface of the surface light source device according to the present embodiment.
- the entrance plane 2 of the light-guide plate 1 has the elliptical arc 10 which is the elliptical arc-shaped concave surface part of the mother ellipse 31 which makes the point light source 13 and the reflector 14 a bifocal point, and is a point light source.
- 13 and the reflector 14 are respectively arranged on one and the other of the elliptical bifocal lines 11 and 12 formed by moving the two focal points of the mother ellipse 31 in the W direction.
- the present embodiment is not limited to this.
- the surface light source device intersects the incident surface 2 of the light guide plate 1 with the incident surface 2 and a surface orthogonal to the W direction that is the width direction of the light guide plate 1.
- the point light source 13 and the reflector 14 are the two focal points of the mother ellipse 31 (that is, the mother ellipse 31 having the point light source 13 and the reflector 14 as two focal points), as in the first and second embodiments. They are arranged on one and the other of elliptical bifocal lines 11 and 12 (see FIG. 1A) that are moved in the W direction of the light guide plate 1, respectively.
- the approximate curve can be obtained by, for example, the least square method.
- the incident surface 2 of the light guide plate 1 is provided with a pseudo elliptical arc 20 in the region where the light emitted from the point light source 13 is incident and the region where the reflected light from the reflector 14 is irradiated.
- the entire incident surface 2 of the light guide plate 1 is not necessarily formed in a pseudo elliptical arc shape.
- the pseudo elliptical arc 20 is provided on at least the main part of the incident surface 2 for the same reason as in the first embodiment.
- the elliptical arc 10 is replaced with an elliptical arc 10 as shown in FIG. It is good also as a pseudo ellipse arc shape by the pseudo ellipse arc 20 approximated by.
- the area irradiated with light from the point light source 13 on the incident surface 2, particularly the incident surface 2, is an elliptic arc of the mother ellipse 31.
- a concave surface portion is provided in a region irradiated with light from the point light source 13 and this concave surface portion is a concave surface portion having a pseudo elliptical arc shape approximated by the elliptical arc of the mother ellipse 31 as described above, an elliptical bifocal point is obtained.
- the light (primary reflected light) incident on the concave surface portion (that is, the pseudo elliptic arc 20) from the point light source 13 on one of the lines 11 and 12 and reflected by the pseudo elliptic arc 20 is more elliptical than the conventional one. It is easy to condense on the other line of the focal lines 11 and 12.
- the degree of condensing of the primary reflected light to the reflector 14 is somewhat lower than that of the first and second embodiments in which the elliptical arc 10 is provided on the incident surface 2, but conventionally.
- a sufficient optical loss reduction effect can be obtained.
- the utilization factor of light source light can be improved compared with the past.
- the pseudo elliptical arc shape means that, for example, as shown in FIG. 11, the width d with the elliptical arc 10 as the center line is 20 as the length of the major axis 32 of the mother ellipse 31 of the elliptical arc 10.
- % In the band region 21 that is less than or equal to% and can be a curved line or a polygonal line connected to both ends of the band region 21 in the length direction.
- the line of intersection between the incident surface 2 and the surface perpendicular to the W direction which is the width direction of the light guide plate 1, has a wavy shape that meanders in the band region 21.
- the light guide plate 1 used in the present embodiment has an incident surface 2 on which the intersection line between the incident surface 2 and a surface perpendicular to the W direction, which is the width direction of the light guide plate 1, is reflected by the point light source 13.
- the band region 21 having a width d that is 20% or less of the length of the major axis 32 of the mother ellipse 31 with the elliptical arc 10 of a part of the mother ellipse 31 having two focal points as the child 14 as the center line
- the belt region 21 may be provided with a concave surface portion having a curved or broken line shape connected to both ends in the T direction which is the length direction thereof.
- the pseudo elliptical arc 20 preferably has a shape as close to the elliptical arc 10 as possible. Therefore, the width d of the band region 21 is preferably 10% or less, more preferably 5% or less of the length of the major axis 32 of the mother ellipse 31.
- the surface emitting light source 15 is provided on one end surface (lateral end portion) of the light guide plate 1
- the present embodiment It is not limited to this.
- FIG. 12 is a perspective view schematically showing a schematic configuration in the vicinity of the incident surface 2 in the surface light source device according to the present embodiment.
- FIGS. 13A and 13B are plan views (planar schematic views) schematically showing a preferred example of the reflector 14 shown in FIG.
- the surface light source device is provided with a dichroic filter 24 on the incident surface 2 of the light guide plate 1 in order to adapt to the case of full color display. It is different from 1-3.
- the dichroic filter 24 is a polarizing filter having a characteristic of selectively transmitting only light having a specific wavelength among the wavelengths of light emitted from the surface emitting light source 15 and reflecting light having a wavelength other than the specific wavelength.
- the dichroic filter 24 preferably has a front surface and a back surface (concave surface and convex back surface) having the same shape as at least the concave portion of the incident surface 2, and the convex back surface is described above.
- the light guide plate 1 having the same shape as the convex back surface is attached to the incident surface 2 (concave surface portion) so as to be matched (fitted).
- the concave surface portion of the incident surface 2 may be a single concave surface portion or a connected concave surface portion such as an elliptical arc 10, a pseudo elliptical arc 20, and a connected elliptical arc 10 (a connected concave surface portion having a connected shape of elliptical arcs). It may be the entire incident surface 2.
- the reflected light from the dichroic filter 24 is condensed on the reflector 14 and reflected by the reflector 14 in the same manner as the reflected light from the incident surface 2 in the case where the dichroic filter 24 is not provided. 24 is irradiated.
- dichroic filter 24 When using the dichroic filter 24, as shown in FIG. 12, a plurality of types of dichroic filters 24 having different selective transmission wavelengths (colors) are often used in combination.
- three types of dichroic filters 24 that selectively transmit the wavelengths of the three primary color lights of R (red), G (green), and B (blue) are arranged in a predetermined direction in the W direction of the incident surface 2.
- a dichroic filter row 29 composed of the dichroic filter 24 is formed on the incident surface 2 by repeatedly arranging in this order with a width (pitch q).
- the dichroic filter 24 that selectively transmits the wavelength of R
- the dichroic filter 24 (G filter) that selectively transmits the wavelength of G
- the wavelength of B are selectively transmitted.
- the dichroic filter 24 (B filter) was disposed in the order of R filter, G filter, and B filter.
- an R filter, a B filter, and a G filter may be repeatedly arranged in another order.
- a dichroic filter 24 that selectively transmits wavelengths of color lights other than R, G, and B for example, C (cyan), M (magenta), and Y (yellow)
- at least one of an R filter, a G filter, and a B filter may be used.
- each of the color sections for example, the R section composed of the R filter, the G section composed of the G filter, and the B section composed of the B filter
- the dichroic filters 24 constituted by the dichroic filters 24 arranged in this way. It is important to irradiate other color zones with light.
- the shape of the reflecting surface 14a (reflecting surface shape) of the reflector 14 is set to a width (pitch q) less than the width (pitch q) of the dichroic filter 24 in the W direction.
- a shape in which prisms are connected to each other a repetitive shape of prisms in a two-surface connection; see FIG. 13A), or a shape in which a lens shape of a columnar aspherical lens is connected (a lens shape of a columnar aspherical lens) It is preferable to adopt a repetitive shape of (see FIG. 13B).
- examples of the shape in which the lens shape of the columnar aspherical lens is continuous include, but are not limited to, a connected shape of a convex lens (a bowl-shaped lens) having a curved surface on one side.
- the shape of the reflecting surface at least a part of the shape in which the two-surface connected shape of the prism as shown in FIG. 13A is continuous is used as the lens of the columnar aspherical lens as shown in FIG. It may be a shape in which each of the above repeated shapes is mixed by replacing the shape with a continuous shape.
- the reflecting surface 14a of the reflector 14 has a prism two-surface connection shape in the W direction at an interval equal to or less than the pitch q of the dichroic filter 24 in the dichroic filter row 29 (more preferably, an interval less than the pitch q). It may have any one surface shape among a repeating shape, a repeating shape of a lens shape of a columnar aspheric lens, and a connecting shape in which a prism two-surface connection shape and a lens shape of a columnar aspheric lens are mixed. preferable.
- a prism two-surface connection shape in the W direction, a prism two-surface connection shape, a columnar aspherical lens lens shape, and their connection at an interval equal to or less than the pitch q of the dichroic filter 24 (more preferably, an interval less than the pitch q). It is more preferable that the surface shape repeat the same shape as any one of the shapes.
- the ratio of the light that is radiated to the reflector 14 from each color group and reflected by the reflector 14 returns to the same color group is reduced, and the light loss is further reduced.
- the surface light source 15 is provided on one end surface (lateral end portion) of the light guide plate 1
- the case where the surface light source 15 is provided on one end surface (lateral end portion) of the light guide plate 1 will be described as an example. However, as described above, It is not limited to this.
- FIG. 13 is a perspective view (three-dimensional schematic diagram) schematically showing a schematic configuration in the vicinity of the incident surface 2 in the surface light source device according to the present embodiment.
- FIG. 14 is a cross-sectional view (cross-sectional schematic diagram) schematically showing a schematic configuration in the vicinity of the light-guide plate incident surface of another surface light source device according to this embodiment in a cross section orthogonal to the W direction.
- the surface light source device includes a polarizing element 25 and a wide viewing angle quarter-wave plate 26 so as to be applied to a display device using polarized light. This is different from the first to third embodiments.
- the polarizing element 25 is a polarizing element that selectively transmits only polarized light in one direction among the wavelengths of light emitted from the surface emitting light source 15 and irradiates the incident surface 2 of the light guide plate 1.
- polarizing element 25 As the polarizing element 25, a wire grid polarizer can be used.
- the wide viewing angle quarter-wave plate 26 is a phase difference plate that changes the polarization direction of the light reflected by the polarizing element 25 by 90 degrees.
- the polarizing element 25 preferably has a front surface and a back surface (concave surface and convex back surface) having the same shape as at least the concave surface portion of the incident surface 2, and the convex back surface is described above.
- the incident surface 2 (concave surface portion) of the light guide plate 1 having the same shape as the convex back surface so that both are aligned (fitted).
- the wide viewing angle quarter-wave plate 26 is preferably disposed on the reflecting surface 14 a of the reflector 14.
- the concave surface portion of the incident surface 2 may be a single concave surface portion or a connected concave surface portion such as an elliptical arc 10, a pseudo elliptical arc 20, and a connected elliptical arc 10 (a connected concave surface portion having a connected shape of elliptical arcs). It may be the entire incident surface 2.
- the reflected light from the polarizing element 25 is condensed on the reflector 14 in the same manner as the reflected light from the incident surface 2 of the light guide plate 1 when the polarizing element 25 is not provided.
- the polarization direction changes by 90 ° and is reflected by the reflecting surface 14a of the reflector 14.
- the polarization direction changes by 180 °.
- the polarization direction changes by 90 ° to become light having the same polarization state as the light source light, and is irradiated again on the polarization element 25. Therefore, light with small variations in polarization state can be efficiently incident on the light guide plate 1.
- a quarter wavelength is provided on the reflecting surface 14a of the reflector 14 as shown in FIG.
- a plate 27 can also be used.
- the quarter-wave plate 27 generates a phase difference of 1/4 only when the light beam is vertically incident. When the light beam is incident at an angle other than vertical, the phase difference of the light beam is 1/4. Deviate from 1. On the other hand, the wide viewing angle quarter-wave plate 27 generates a phase difference of the light beam by a quarter, regardless of whether the light beam is incident vertically or incident at an angle from the vertical.
- the quarter-wave plate is formed of a uniaxial refractive index medium, and the wide viewing angle quarter-wave plate is formed of a biaxial refractive index medium. For this reason, the characteristic difference as described above occurs.
- the angle at which light is incident on the concave surface portion (for example, elliptical arc 10) of the incident surface 2 from a light source such as the point light source 13 is not limited to vertical. Therefore, the quarter-wave plate 26 with a wide viewing angle is more suitable than the quarter-wave plate 27. However, the wide viewing angle quarter-wave plate 26 is more expensive than the quarter-wave plate 27. For this reason, the quarter-wave plate 27 can be used when cost reduction is given priority at the expense of some characteristics.
- Example 1 a surface light source device of the form shown in FIGS. 1A and 1B is prototyped, the point light source 13 composed of LEDs is turned on, and the luminance of a predetermined area in the emission surface 7 is The measurement was performed with a spectroradiometer (“SR-UL1R” (trade name) manufactured by Topcon Technohouse).
- SR-UL1R spectroradiometer
- the point light source 13, the reflector 14, and the exit surface 7 were surrounded by a reflector 18 (see FIG. 2) similar to the reflector 104 shown in FIG.
- the cross section was processed into a concave shape with an elliptical arc shape.
- an elliptical arc-shaped concave surface (elliptical arc 10) was formed on the incident surface 2.
- the point light source 13 and the reflector 14 are disposed on one and the other of the elliptical bifocal lines 11 and 12.
- Comparative Example 1 On the other hand, as a comparative example, a surface light source device having the same form as that of Example 1 except that the surface shape of the incident surface 2 was changed from a concave shape to a planar shape in Example 1 was measured. The brightness was measured by this method.
- Example 1 the measured luminance value of Example 1 was about 12% higher than the measured luminance value of Comparative Example 1. Thereby, the effect of the present invention was confirmed.
- the surface light source device of the present invention can be suitably used for a backlight of a transmissive LCD or a transflective LCD, an auxiliary light source (front light) of a reflective LCD, or the like.
Abstract
Description
本発明の実施の一形態について図1の(a)・(b)~図9に基づいて説明すれば、以下の通りである。
本発明の実施の他の形態について、主に図10の(a)~(c)に基づいて説明すれば、以下の通りである。
本発明の実施の他の形態について、主に図11に基づいて説明すれば、以下の通りである。
本発明の実施の他の形態について、主に図12および図13の(a)・(b)に基づいて説明すれば、以下の通りである。
本発明の実施の他の形態について、主に図14および図15に基づいて説明すれば、以下の通りである。
本実施例では、図1の(a)・(b)に示した形態の面光源装置を試作し、LEDで構成した点光源13を点灯して、射出面7内の所定領域の輝度を、分光放射計(トプコンテクノハウス社製の「SR-UL1R」(商品名))で測定した。
一方、比較例として、実施例1において入射面2の面形状を凹面形状から平面形状に変更した以外は、実施例1と同じ形態とした面光源装置を試作し、実施例1と同様の測定方法で輝度を測定した。
2 入射面(導光板入射面)
7 射出面(導光板射出面)
8 裏面(導光板裏面)
10 楕円弧(凹面部)
10A 楕円弧(凹面部)
11 楕円二焦点線(平行二軌跡直線)
11A 楕円二焦点線(平行二軌跡直線)
12 楕円二焦点線(平行二軌跡直線)
12A 楕円二焦点線(平行二軌跡直線)
13 点光源(光源)
14 反射子
14A 反射子
14a 反射面
15 面発光光源(光源)
16 短軸
17 交線
18 リフレクタ
20 擬似楕円弧(凹面部)
21 帯領域
22 反射主光線
23 放射主光線
24 ダイクロイックフィルタ
25 偏光素子
26 広視野角4分の1波長板
27 4分の1波長板
28 反射鏡
28a 反射面
29 ダイクロイックフィルタ列
31 母楕円
31A 母楕円
32 長軸
P 交点
q ピッチ
Claims (15)
- 少なくとも一つの光源と、
板の長さ方向の少なくとも一端部を導光板入射面とし、前記板の厚さ方向の両端部をそれぞれ導光板射出面、導光板裏面として前記光源から発した光を前記導光板入射面から導入し、前記導光板射出面のほぼ全域に広げて射出させる前記板からなる導光板と、
前記光源から放射された光のうち前記導光板入射面で反射された光を、さらに反射して前記導光板入射面に照射する、少なくとも一つの反射子とを有する面光源装置において、
前記導光板入射面は、前記光源と前記反射子とを二焦点とする母楕円の一部をなす楕円弧と同じ形状を有する凹面部を備え、
前記光源と前記反射子とは、前記凹面部を楕円弧として含む母楕円の二焦点を前記導光板の幅方向に移動してなる平行二軌跡直線の一方と他方の線上にそれぞれ配置されていることを特徴とする面光源装置。 - 前記凹面部は、前記板の厚さ方向に一つ設けられており、
前記導光板入射面における、少なくとも、前記導光板入射面の周縁部以外の部分と、前記導光板の幅方向に直交する面との交線は、前記凹面部からなる単一の楕円弧形をなしていることを特徴とする請求項1記載の面光源装置。 - 前記凹面部は、前記板の厚さ方向に複数設けられており、
前記導光板入射面における、少なくとも、前記導光板入射面の周縁部以外の部分と、前記導光板の幅方向に直交する面との交線は、前記複数の凹面部からなる複数の楕円弧の連結形をなし、
前記光源と前記反射子とは、前記板の厚さ方向に設けられた各凹面部に対し、それぞれの凹面部をそれぞれ楕円弧として含む各母楕円の各二焦点を前記導光板の幅方向に移動してなる平行二軌跡直線の一方と他方の線上にそれぞれ配置されていることを特徴とする請求項1記載の面光源装置。 - 少なくとも一つの光源と、
板の長さ方向の少なくとも一端部を導光板入射面とし、前記板の厚さ方向の両端部をそれぞれ導光板射出面、導光板裏面として前記光源から発した光を前記導光板入射面から導入し、前記導光板射出面のほぼ全域に広げて射出させる前記板からなる導光板と、
前記光源から放射された光のうち前記導光板入射面で反射された光を、さらに反射して前記導光板入射面に照射する、少なくとも一つの反射子とを有する面光源装置において、
前記導光板入射面は、前記導光板入射面と前記導光板の幅方向に直交する面との交線が、曲線または折れ線形状をなし、かつ、この交線の近似曲線が前記光源と前記反射子とを二焦点とする母楕円の一部とほぼ一致する、擬似楕円弧状の凹面部を備え、
前記光源と前記反射子とは、前記母楕円の二焦点を前記導光板の幅方向に移動してなる平行二軌跡直線の一方と他方の線上にそれぞれ配置されていることを特徴とする面光源装置。 - 前記光源が、白色LED光源、RGB-LED光源、マルチカラーLED光源、有機EL光源、レーザ光源からなる群より選ばれる少なくとも一種の光源であることを特徴とする請求項1~4の何れか1項に記載の面光源装置。
- 前記反射子の反射面が、平面、球面、楕円筒面、およびこれらの二つ以上の連結面のうち何れか一つの形状を有していることを特徴とする請求項1~5の何れか1項に記載の面光源装置。
- 前記反射子は、その反射主光線が、前記楕円弧の母楕円の短軸と前記楕円弧との交点を前記導光板の幅方向に移動してなる軌跡直線と交わるように、その反射面の向きが調節されていることを特徴とする請求項1~6の何れか1項に記載の面光源装置。
- 前記光源は、その放射主光線が、前記楕円弧の母楕円の短軸と前記楕円弧との交点を前記導光板の幅方向に移動してなる軌跡直線と交わるように、光の照射方向が調節されていることを特徴とする請求項1~7の何れか1項に記載の面光源装置。
- 前記導光板入射面の凹面部と前記導光板の厚さ方向に直交する面とがなす交線が、筒状非球面レンズアレイと同筒軸直交面との交線形状と同じ形状を有し、
前記反射子の反射面が、前記導光板入射面の凹面部と相似な形状の凸面であることを特徴とする請求項1~8の何れか1項に記載の面光源装置。 - 前記光源から放射される光の波長のうち、特定の波長の光のみを選択透過させ、該特定の波長以外の波長の光を反射させるダイクロイックフィルタをさらに備え、
該ダイクロイックフィルタは、前記導光板入射面の凹面部と同じ形状の凹表面および凸裏面を有し、該凸裏面が前記導光板入射面の凹面部に整合して付着されていることを特徴とする請求項1~9の何れか1項に記載の面光源装置。 - 前記ダイクロイックフィルタは、前記導光板の幅方向に複数設けられているとともに、互いに隣接するダイクロイックフィルタは、選択透過させる波長が互いに異なっており、
前記反射子の反射面形状が、前記導光板の幅方向に、前記ダイクロイックフィルタのピッチ以下の間隔で、プリズムの二面連結形状、柱状非球面レンズのレンズ形状、およびこれらの連結形状のうち何れか一種の形状と同じ形状を繰り返す面形状であることを特徴とする請求項10に記載の面光源装置。 - 前記ダイクロイックフィルタは、前記導光板の幅方向に複数設けられているとともに、互いに隣接するダイクロイックフィルタは、選択透過させる波長が互いに異なっており、
前記反射子の反射面形状が、前記導光板の幅方向に、前記ダイクロイックフィルタのピッチ以下の間隔で、プリズムの二面連結形状の繰り返し形状、柱状非球面レンズのレンズ形状の繰り返し形状、およびプリズムの二面連結形状と柱状非球面レンズのレンズ形状とが混在した連結形状のうち何れか一種の面形状を有していることを特徴とする請求項10に記載の面光源装置。 - 前記光源から放射される光の波長のうち一方向の偏光のみを選択透過させて前記導光板入射面に照射させる偏光素子と、
該偏光素子で反射された光の偏光方向を90度変化させる広視野角4分の1波長板とを、さらに備え、
前記偏光素子は、前記導光板入射面の凹面部と同じ形状の凹表面および凸裏面を有し、該凸裏面が前記導光板入射面の凹面部と整合して、前記導光板入射面に付着され、
前記広視野角4分の1波長板は、前記反射子の反射面上に配置されていることを特徴とする請求項1~10の何れか1項に記載の面光源装置。 - 前記光源から放射される光の波長のうち一方向の偏光のみを選択透過させて前記導光板入射面に照射させる偏光素子と、4分の1波長板とを、さらに備え、
前記偏光素子は、前記導光板入射面の凹面部と同じ形状の凹表面と、凸裏面とを有し、
該凸裏面が前記導光板入射面の凹面部と整合して、前記導光板入射面に付着され、
前記4分の1波長板は、前記反射子の反射面上に配置されていることを特徴とする請求項1~10の何れか1項に記載の面光源装置。 - 前記導光板裏面に対向する反射鏡をさらに備え、
該反射鏡における前記導光板裏面との対向面は、前記導光板裏面の面積以上の面積を有する反射面であることを特徴とする請求項1~14の何れか1項に記載の面光源装置。
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US8777455B2 (en) | 2011-06-23 | 2014-07-15 | Cree, Inc. | Retroreflective, multi-element design for a solid state directional lamp |
US8777463B2 (en) | 2011-06-23 | 2014-07-15 | Cree, Inc. | Hybrid solid state emitter printed circuit board for use in a solid state directional lamp |
US8616724B2 (en) * | 2011-06-23 | 2013-12-31 | Cree, Inc. | Solid state directional lamp including retroreflective, multi-element directional lamp optic |
US8757840B2 (en) | 2011-06-23 | 2014-06-24 | Cree, Inc. | Solid state retroreflective directional lamp |
USD696436S1 (en) | 2011-06-23 | 2013-12-24 | Cree, Inc. | Solid state directional lamp |
KR101909602B1 (ko) * | 2011-08-17 | 2018-10-18 | 엘지전자 주식회사 | 이동 단말기 |
CN102913816B (zh) * | 2012-09-28 | 2015-11-11 | 京东方科技集团股份有限公司 | 侧光式背光模组及液晶显示装置 |
CN104854397B (zh) * | 2012-12-18 | 2018-10-23 | 飞利浦灯具控股公司 | 照明条、照明系统、面板支撑元件和模块化面板系统 |
WO2015046239A1 (ja) * | 2013-09-25 | 2015-04-02 | 堺ディスプレイプロダクト株式会社 | 照明装置及び表示装置 |
KR20190079727A (ko) * | 2017-12-27 | 2019-07-08 | 삼성디스플레이 주식회사 | 표시 장치 |
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