WO2012147646A1 - Light source device, surface light source device, display device, and illumination device - Google Patents

Light source device, surface light source device, display device, and illumination device Download PDF

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Publication number
WO2012147646A1
WO2012147646A1 PCT/JP2012/060709 JP2012060709W WO2012147646A1 WO 2012147646 A1 WO2012147646 A1 WO 2012147646A1 JP 2012060709 W JP2012060709 W JP 2012060709W WO 2012147646 A1 WO2012147646 A1 WO 2012147646A1
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WO
WIPO (PCT)
Prior art keywords
light
light source
source device
concave mirror
light emitting
Prior art date
Application number
PCT/JP2012/060709
Other languages
French (fr)
Japanese (ja)
Inventor
昇平 勝田
豪 鎌田
大祐 篠崎
昌洋 ▲辻▼本
Original Assignee
シャープ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2011102404A external-priority patent/JP2014135120A/en
Priority claimed from JP2011107718A external-priority patent/JP2014135121A/en
Application filed by シャープ株式会社 filed Critical シャープ株式会社
Publication of WO2012147646A1 publication Critical patent/WO2012147646A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0031—Reflecting element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0055—Reflecting element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
    • G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources

Definitions

  • the present invention relates to a light source device, a surface light source device, a display device, and an illumination device.
  • This application claims priority based on Japanese Patent Application No. 2011-102404 filed in Japan on April 28, 2011 and Japanese Patent Application No. 2011-107718 filed in Japan on May 13, 2011. Is hereby incorporated by reference.
  • a transmissive liquid crystal display device that performs display using light emitted from a surface light source device.
  • This type of liquid crystal display device has a liquid crystal panel and a surface light source device disposed on the back side of the liquid crystal panel.
  • a conventional surface light source device includes a light source such as a light emitting diode (hereinafter abbreviated as “LED”) and a light guide plate, and propagates light emitted from the light source inside the light guide plate. It is common to inject from.
  • LED light emitting diode
  • the surface light source device provided on the back side of the display panel may be referred to as a backlight.
  • a reflection type light source device having a light source such as an LED and a reflector that reflects light from the LED is known.
  • the reflector has a shape obtained by rotating the paraboloid around the axis.
  • the light emitting point of the LED is located at the focal point of the paraboloid of the reflector, and the light from the LED is reflected by the reflector and emitted with high directivity.
  • Patent Document 1 discloses a backlight device including a plurality of light source devices and a light guide plate in which these light source devices are arranged on an end surface.
  • the light source device includes an LED and a reflector that reflects light from the LED.
  • the reflector has a shape in which the paraboloid is divided in half by a horizontal plane passing through its axis. The light emitting point of the LED is located at the focal point of the paraboloid of the reflector.
  • the light distribution of LEDs is a general Lambertian distribution.
  • the in-plane illuminance distribution after being reflected by the reflector is brighter as it is closer to the center and darker as it is closer to the outer periphery of the reflector. Distribution.
  • a light source with a non-uniform in-plane luminance distribution as an incident light source for a surface light source (hereinafter referred to as a backlight) provided on the back side of a display panel of a liquid crystal display device, for example, uneven brightness occurs in the light emitting surface. As a result, the image of the liquid crystal display device cannot be displayed correctly.
  • An aspect of the present invention has been made to solve the above-described problem, and an object thereof is to provide a surface light source device that can obtain light with high directivity. Moreover, it aims at providing the display apparatus and illuminating device provided with this kind of surface light source device.
  • an aspect of the present invention is made to solve the problem caused by the in-plane illuminance non-uniformity of the above-described light source device, and can obtain light with high directivity and uniform in-plane distribution.
  • An object of the present invention is to provide a simple light source device. Moreover, it aims at providing the display apparatus and illuminating device provided with this kind of light source device.
  • a surface light source device includes a light source having at least a light emitting element having a light emitting surface and a concave mirror that reflects light emitted from the light emitting element, and the light source.
  • a light guide that causes the emitted light to enter from the end face, propagate inside, and exit from the main surface, and the concave mirror is a cross-section taken along a plane parallel to the main surface of the light guide.
  • the shape has at least a part of a curved shape having a focal point, and the light emitting element is disposed such that the focal point is located on the light emitting surface, and light from the light emitting element is provided on the concave mirror. Via the light guide.
  • the light guide may have a reflecting surface that forms a predetermined inclination angle with respect to the main surface in the light propagation direction.
  • the light source may include a convex lens disposed in a recess of the concave mirror, and the position of the focal point of the convex lens may substantially coincide with the position of the focal point of the concave mirror.
  • the concave mirror may be formed of a metal film formed on the convex surface of the convex lens.
  • a groove may be provided on a surface facing the convex surface of the convex lens, and the light emitting element may be disposed inside the groove.
  • the cross-sectional shape of the bottom of the groove when cut along a plane parallel to the main surface of the light guide may be curved.
  • a cross-sectional shape of the concave mirror when cut along a plane perpendicular to the main surface of the light guide may be a linear shape.
  • a plurality of the light sources may be arranged on the end surface of the light guide in a direction parallel to the main surface and perpendicular to the light propagation direction.
  • the plurality of light sources may be arranged in a plurality of rows in a direction perpendicular to the main surface.
  • the plurality of light sources forming one row may have different dimensions in the arrangement direction of the concave mirrors.
  • the positions of the light emitting elements in the arrangement direction of the light sources may be different for each column.
  • the light guide has a wedge shape in which the thickness decreases from the side near the end surface toward the side far from the end surface, and the entire surface facing the main surface is The reflective surface may be used.
  • the light guide has a plurality of prism structures on a surface facing the main surface, and one inclined surface of the prism structure is the reflection surface. Also good.
  • the surface light source device further includes a direction changing member that changes a traveling direction of light emitted from the main surface of the light guide to a direction closer to a normal line of the main surface. Also good.
  • a display device includes the above surface light source device and a display element that performs display using light emitted from the surface light source device.
  • An illumination device includes the surface light source device.
  • a light source device includes a first light emitting element having a first light emitting surface, a concave mirror that reflects light emitted from the first light emitting element, and a progression of at least a part of incident light.
  • the concave mirror includes a direction changing element for changing a direction, and the concave mirror has a curved shape having a focal point at least in part when cut along a plane parallel to the light emitting surface, and the focal point is the first
  • the first light emitting surface of the light emitting element and any one of the direction changing elements, or a line connecting the first light emitting surface and the direction changing element, are arranged such that at least a part of the light from the first light emitting element travels in the traveling direction by the direction changing element. And is emitted through the concave mirror.
  • the light source device may be a half mirror in which the direction changing element transmits at least part of incident light and reflects light that has not been transmitted.
  • the curved shape may be a paraboloid.
  • the light source device may further include a mirror disposed between the first light emitting element and the direction changing element.
  • the light source device may further include a mirror disposed so as to surround a surface other than the curved shape of the concave mirror.
  • the concave mirror may have a curved shape cut along the symmetry axis, and the mirror may be installed on the symmetry axis.
  • the light source device may have a curved surface shape even if the concave mirror is cut at any plane passing through the central axis of the curved shape of the concave mirror.
  • the direction changing element may have a conical shape.
  • the light emitting main surface of the light emitting element may face the concave mirror side.
  • the first light emitting surface may face the concave mirror.
  • the first light emitting surface may be parallel to a curved central axis of the concave mirror.
  • the first light emitting element may be a white LED.
  • the first light emitting element may be a blue LED.
  • the first light emitting element may be an ultraviolet LED.
  • the half mirror may be formed of a transparent base material and a reflective portion formed of a metal film on the transparent base material.
  • the reflecting portion may have a dot shape.
  • the reflecting portion may have a stripe shape.
  • the reflecting portion may have a wave shape.
  • a surface light source device includes the light source device, and a light guide that causes light emitted from the light source device to enter from an end surface, propagate inside, and exit from a main surface. Yes.
  • the light guide may have a reflective surface that forms a predetermined inclination angle with respect to the main surface in the light propagation direction.
  • the light guide may have a wedge shape whose thickness decreases from a side closer to the end surface toward a side farther from the end surface.
  • a plurality of the light sources may be arranged on the end surface of the light guide in a direction parallel to the main surface and perpendicular to the light propagation direction.
  • the surface light source device further includes a direction changing member that changes a traveling direction of light emitted from the main surface of the light guide to a direction closer to a normal line of the main surface. It may be.
  • a display device includes the surface light source device and a display element that performs display using light emitted from the surface light source device.
  • the display device may be a liquid crystal panel in which the display element has a viewing angle widening film.
  • the display element may be a fluorescence excitation type liquid crystal panel.
  • the surface light source device further includes a second light emitting element having a second light emitting surface facing the light guide, and the first light emitting surface faces the concave mirror.
  • the first light emitting element may be disposed, and the second light emitting element may be disposed such that the second light emitting surface faces the light guide.
  • a display device includes the surface light source device and a display element that performs display using light emitted from the surface light source device.
  • the display element may be a liquid crystal panel in which liquid crystal alignment is parallel to the substrate and is switched by an electric field applied in a parallel direction.
  • a lens is installed on the back surface of the light emitting element.
  • the direction changing element may be a lens.
  • the lens may have a curved surface that can be approximated by a quartic function.
  • a surface light source device that can obtain light with high directivity. Moreover, a display apparatus and an illuminating device provided with this kind of surface light source device can be provided.
  • a light source device capable of obtaining emitted light with high directivity and high in-plane luminance uniformity.
  • a surface light source device, a display device, and an illumination device including this type of light source device can be provided.
  • FIG. 2 is a cross-sectional view taken along the line A-A ′ of FIG. 1. It is a perspective view which shows one light source in the surface light source device of this embodiment.
  • FIG. 4 is a sectional view taken along line B-B ′ of FIG. 3.
  • FIG. 4 is a cross-sectional view taken along line C-C ′ of FIG. 3.
  • It is a front view which shows the some light source in the surface light source device of this embodiment.
  • FIG. 13 is a cross-sectional view taken along the line A-A ′ of FIG. 12.
  • FIG. 13 is a sectional view taken along line B-B ′ of FIG. 12. It is a shape figure of the reflection part of the half mirror of 8th Embodiment of this invention. It is a shape figure of the reflection part of the half mirror of 8th Embodiment of this invention. It is a shape figure of the reflection part of the half mirror of 8th Embodiment of this invention. It is sectional drawing which shows the light source device of 9th Embodiment of this invention. It is a perspective view which shows the light source device of 10th Embodiment of this invention. It is a perspective view which shows the light source device of 11th Embodiment of this invention. It is sectional drawing which shows the light source device of 11th Embodiment of this invention.
  • FIG. 1 is a perspective view showing the surface light source device of this embodiment.
  • FIG. 2 is a cross-sectional view taken along line AA ′ of FIG.
  • FIG. 3 is a perspective view showing one light source in the surface light source device of the present embodiment.
  • 4A is a cross-sectional view taken along the line BB ′ of FIG. 3
  • FIG. 4B is a cross-sectional view taken along the line CC ′ of FIG.
  • FIG. 5 is a front view showing a plurality of light sources in the surface light source device of the present embodiment.
  • the scale of the size may be varied depending on the component.
  • the surface light source device 11 of this embodiment is comprised from the light source part 12, the light guide 13, and the prism sheet 14 (direction changing member, direction changing member), as shown in FIG. 1 and FIG. Yes.
  • the light guide 13 has a function of causing light emitted from the light source unit 12 to enter from the end face and to be emitted from the main surface while propagating inside.
  • the prism sheet 14 has a function of changing the traveling direction of the light emitted from the main surface of the light guide 13 to a direction closer to the normal line of the main surface. The detailed configuration of the light source unit 12 will be described later.
  • the light guide 13 is a plate made of a resin having optical transparency such as acrylic resin.
  • the light guide 13 has a wedge shape in which the thickness gradually decreases from the side closer to the end surface 13 a where the light source unit 12 is provided to the side farther from the side. That is, as shown in FIG. 2, the cross-sectional shape of the light guide 13 when cut along a plane (xz plane) perpendicular to the first main surface 13b described later is a right triangle.
  • the end surface 13 a of the light guide 13 is a light incident surface on which light emitted from the light source unit 12 is incident.
  • the first main surface 13b (upper surface in FIG. 2) of the light guide 13 is a light emitting surface for emitting light incident on the inside.
  • the light propagation direction within the first main surface 13b of the light guide 13 is the x-axis direction
  • the direction orthogonal to the light propagation direction is the y-axis direction
  • the first main surface is orthogonal.
  • the direction (thickness direction of the light guide 13) is defined as the z-axis direction. Therefore, “the propagation direction of light” in this specification means the direction in which light (indicated by a dashed-dotted arrow L) propagates while reflecting in the xz section of the light guide 13 shown in FIG. Instead, it means a direction (indicated by a solid arrow X) in which light propagates when viewed from the normal direction of the first main surface 13b of the light guide 13.
  • the second main surface 13c (the lower surface in FIG. 2) facing the first main surface 13b of the light guide 13 is inclined with a certain inclination angle with respect to the first main surface 13b in the light propagation direction. Yes.
  • the inclination angle ⁇ 1 of the second main surface 13c with respect to the first main surface 13b (the angle between the first main surface 13b and the second main surface 13c, sometimes referred to as the tip angle of the light guide 13) is, for example, 2 °. Set to degree.
  • the second main surface 13c is provided with a reflection mirror 15 made of a metal film having a high light reflectance such as aluminum. By providing the reflection mirror 15, the second main surface 13 c functions as a reflection surface that reflects the light propagating through the light guide 13 as a whole.
  • the reflection mirror 15 may be formed of a metal film directly formed on the second main surface 13c of the light guide 13, or a structure in which a reflection plate manufactured separately from the light guide 13 is bonded. It is also good.
  • the light source unit 12 has a configuration in which a plurality of light sources 16 are arranged in a line in a direction (y-axis direction) orthogonal to the light propagation direction X.
  • the light source 16 includes an LED 17 (light emitting element), a cylindrical lens 18 (convex lens), and a concave mirror 19.
  • the cylindrical lens 18 is made of a resin such as an acrylic resin.
  • the cylindrical lens 18 is a so-called plano-convex lens in which one is a convex surface and the other is a flat surface.
  • the flat surface 18a Since light is emitted from the flat surface 18a, the flat surface 18a is hereinafter referred to as a light emission surface.
  • the convex surface has a curved surface 18b that is gently curved, and two flat side surfaces 18c that are continuous to both ends of the curved surface 18b.
  • the curved surface 18b of the convex surface has a curved shape having a focal point P as shown in FIG. 4A.
  • the cross-sectional shape of the curved surface 18b is a parabolic shape.
  • the curved surface 18b is linear as shown in FIG. 4B. That is, the curved surface 18b of the cylindrical lens 18 is a paraboloid that is curved in the xy plane and not curved in the xy plane.
  • a concave mirror 19 is provided along the curved surface 18 b of the cylindrical lens 18.
  • the concave mirror 19 is made of a metal film having a high light reflectance such as aluminum directly formed on the curved surface 18 b of the cylindrical lens 18.
  • the shape of the concave mirror 19 becomes a paraboloid reflecting the shape of the curved surface 18b. Therefore, the focal position of the concave mirror 19 coincides with the focal position of the cylindrical lens 18.
  • the focal point is indicated by point P in FIG.
  • a configuration may be adopted in which a concave mirror manufactured separately from the cylindrical lens is bonded.
  • the light exit surface 18a of the cylindrical lens 18 is provided with a groove 110 having a depth sufficient to insert the LED 17 therein.
  • the cross-sectional shape of the bottom of the groove 110 when the cylindrical lens 18 is cut along the xy plane is rounded into an arc.
  • a rod-shaped LED 17 is arranged inside the groove 110.
  • the LED 17 is arranged in a posture in which the light emitting surface 17 a faces the concave mirror 19. Further, the LED 17, the concave mirror 19 and the cylindrical lens 18 are set such that their positional relationship, size, shape and the like are set so that the focal point P of the concave mirror 19 and the cylindrical lens 18 is located on the light emitting surface 17a.
  • the LED 17 Since the light emitting surface 17a of the LED 17 faces the concave mirror 19, almost all of the light emitted from the light emitting surface 17a of the LED 17 is directed to the concave mirror 19, reflected by the concave mirror 19, and then emitted from the cylindrical lens 18. Ejected from the surface 18a. Therefore, of the light emitted from the light emitting surface 17a of the LED 17, there is almost no light emitted directly without being reflected by the concave mirror 19.
  • the LED 17 is not particularly directional, and a general LED that emits light at a predetermined diffusion angle can be used.
  • the convex surface of the cylindrical lens 18 At least a parabolic surface reaches a position where the light emitted from the LED 17 reaches the maximum diffusion angle, and the concave mirror 19 exists. Therefore, the portion where the light from the LED 17 does not reach is a flat side surface 18c, and the concave mirror 19 does not exist.
  • the side surface 18c of the cylindrical lens 18 is a contact surface that contacts the side surface 18c of the adjacent cylindrical lens 18.
  • a groove 110 is provided so as to penetrate from the upper end to the lower end on the light exit surface 18 a of each cylindrical lens 18.
  • the LED 17 is provided over the entire groove 110 so as to reach from the upper end to the lower end of the cylindrical lens 18.
  • Wiring (not shown) for supplying current to the LED 17 is drawn from the upper end and the lower end of the cylindrical lens 18.
  • a slight gap 111 ⁇ / b> A is provided between the LED 17 and the groove 110.
  • the gap 111A may be filled with an optical adhesive or the like, or air may be present without filling anything.
  • a plurality of separate cylindrical lenses 18 are connected, but a lenticular lens having a structure in which these plurality of cylindrical lenses are integrated may be used.
  • the prism sheet 14 is provided at a position (above the light guide 13 in FIG. 2) facing the first main surface (light emission surface) 13 b of the light guide 13. .
  • the prism sheet 14 is provided with a plurality of prism structures 111 extending in a direction orthogonal to the light propagation direction X on one surface.
  • the prism sheet 14 is disposed so that the surface on which the plurality of prism structures 111 are provided faces the light exit surface 13 b of the light guide 13.
  • the cross-sectional shape of one prism structure 111 in a cross section cut along the xz plane is a triangular shape.
  • the prism structure 111 includes a first surface 111a that is orthogonal to the light exit surface 13b of the light guide 13, and a second surface 111b that forms a predetermined tip angle ⁇ 2 with respect to the first surface 111a. Yes.
  • the operation of the surface light source device 11 configured as described above will be described. Since the light emitting surface 17a of the LED 17 has a predetermined area, not all points on the light emitting surface 17a necessarily coincide with the positions of the focal point P of the concave mirror 19 and the cylindrical lens 18. However, for the sake of simplicity, the following description will be made assuming that the area of the light emitting surface 17a is sufficiently small and the light emitting surface 17a is coincident with the focal point P.
  • the light L emitted from the light emitting surface 17a of the LED 17 is directed to the concave mirror 19 with a predetermined diffusion angle and reflected by the concave mirror 19.
  • the behavior of light in a plane (xy plane) parallel to the light exit surface 13b of the light guide 13 is considered.
  • the light L emitted from the LED 17 can be incident on the concave mirror 19 at any angle. Then, the light travels in a direction parallel to the optical axis of the concave mirror 19.
  • the diffused light immediately after being emitted from the light emitting surface 17a of the LED 17 is converted into parallel light by being reflected by the concave mirror 19, that is, light having high directivity, and the light emitting surface 18a of the cylindrical lens 18 is converted. Is injected from.
  • the concave mirror 19 functions like a plane mirror. That is, the light L is reflected by the concave mirror 19 at a reflection angle equal to the incident angle. Therefore, the light L is emitted from the light emitting surface 18a of the cylindrical lens 18 while maintaining the diffusion angle immediately after being emitted from the light emitting surface 17a of the LED 17.
  • the light L when the light L is emitted from the light exit surface 18a of the cylindrical lens 18, the light L has high directivity only in a plane (xy plane) parallel to the light exit surface 13b of the light guide 13. In a plane (xz plane) parallel to the light propagation direction X and perpendicular to the light exit surface 13b of the light guide 13, there is no directivity.
  • Such light L is incident on the light guide 13 from the light incident surface (end surface) 13a.
  • the light L incident on the light guide 13 from the light incident surface (end surface) 13a is, as shown in FIG. 2, a first main surface 13b (light emission surface) and a second main surface 13c (reflection surface).
  • the light guide 13 travels in the light propagation direction X (right side in FIG. 2) while repeating the reflection. Assuming that the first main surface and the second main surface are parallel, the incident angle of light on the first main surface and the second main surface does not change even if light is repeatedly reflected.
  • the light guide 13 has a wedge shape in which the thickness gradually decreases with increasing distance from the light incident surface 13a side, and the second main surface 13c has a predetermined inclination angle with respect to the first main surface 13b. Have. Therefore, each time the light L is reflected by the first main surface 13b and the second main surface 13c, the incident angle on the first main surface 13b and the second main surface 13c becomes small.
  • the critical angle on the first main surface 13b (light emission surface) of the light guide 13 is shown. That is, the critical angle at the interface between the acrylic resin constituting the light guide 13 and the air is about 42 ° from Snell's law.
  • the total reflection condition is satisfied as long as the incident angle of the light L on the first main surface 13b is larger than 42 ° which is a critical angle. Therefore, the light L is totally reflected by the first main surface 13b.
  • the incident angle of the light L on the first main surface 13b becomes smaller than 42 ° which is a critical angle.
  • the light L is emitted to the external space because the total reflection condition is not satisfied.
  • the light L is confined inside the light guide 13 while the incident angle on the first main surface 13b is larger than the critical angle, and the incident angle on the first main surface 13b becomes smaller than the critical angle.
  • the first main surface 13b is sequentially ejected. Since the light L is refracted when emitted from the first main surface 13b, light having an incident angle of about 42 ° to the first main surface 13b is emitted as light having an emission angle of about 70 °.
  • the light L is directional at the point of incidence on the light guide 13.
  • it has high directivity.
  • the emission angle of the light L when emitted from the light guide 13 is about 70 °, and the light L is emitted in a substantially horizontal direction. Therefore, it is necessary to use the prism sheet 14 to raise the light L emitted from the light guide 13 in a direction close to the normal direction of the first main surface 13 b of the light guide 13.
  • a prism sheet 14 having a prism structure 111 with a tip angle ⁇ 2 of about 38.5 ° is used, and light L is incident from the first surface 111a of the prism structure 111 and reflected by the second surface 111b. By doing so, the light guide 13 can be raised in a substantially normal direction with respect to the first main surface 13b.
  • the light emitted from the LED 17 is reflected by the concave mirror 19 of the light source 16, so that it is high in a plane (xy plane) parallel to the light exit surface 13 b of the light guide 13.
  • high directivity can be achieved even in a plane (xz plane) parallel to the light propagation direction X and perpendicular to the light exit surface 13b of the light guide 13. You can have it.
  • light having high directivity can be extracted in the normal direction of the first main surface 13 b of the light guide 13 by transmitting the light through the prism sheet 14. As a result, light having high directivity at all azimuth angles can be obtained.
  • the present inventors performed an optical simulation on the luminance-angle profile of light emitted from the light guide on the premise of the surface light source device of the present embodiment.
  • the radius of curvature of the concave mirror is 2.5 mm
  • the width of the cylindrical lens is 5 mm
  • the width of the LED is 0.4 mm
  • the tip angle of the light guide is Set to 2 °.
  • the surface light source device of this embodiment light having a high directivity with a full width at half maximum of 15 ° or less at all azimuth angles centered on the normal direction of the first main surface of the light guide. It was confirmed that
  • the concave mirror 19 is formed directly on the curved surface 18b of the cylindrical lens 18, and the LED 17 is inserted into the groove 110 provided in the cylindrical lens 18.
  • the number of parts is small, and the light source unit 12 that is relatively small with respect to the size of the light guide 13 can be manufactured.
  • the light source unit 12 includes a plurality of light sources 16 arranged in a direction orthogonal to the light propagation direction X, the surface light source device 11 corresponding to the light guide 13 having a high luminance and a wide width is configured. can do.
  • the corner is composed of two planes (a first plane and a second plane) orthogonal to each other.
  • the light refraction direction changes abruptly when light emitted from the LED is incident on the first plane and when incident on the second plane. Therefore, the angle-luminance characteristic of the light finally emitted from the surface light source device has a plurality of peaks.
  • the bottom of the groove 110 of the present embodiment is rounded in an arc shape, the refraction direction of the light emitted from the LED 17 does not change abruptly. As a result, light having a gentle angle-luminance characteristic can be obtained.
  • FIG. 6 is a cross-sectional view of the surface light source device of the present embodiment cut along the xz plane, and corresponds to FIG. 2 of the first embodiment.
  • FIG. 6 the same components as those in FIG.
  • the surface light source device 114 of this embodiment includes a light source unit 12, a light guide 115, and a prism sheet 14, as shown in FIG.
  • the configurations of the light source unit 12 and the prism sheet 14 are the same as those in the first embodiment.
  • the light guide 115 is provided with a plurality of prism structures 116 extending in a direction orthogonal to the light propagation direction X (y-axis direction).
  • the light guide 115 is disposed so that the surface on which the plurality of prism structures 116 are provided faces the opposite side to the prism sheet 14.
  • the cross-sectional shape of one prism structure 116 cut along the xz plane is triangular.
  • the prism structure 116 includes a first surface 116a that is orthogonal to the first main surface 115b of the light guide 115, and a second surface 116b that forms a predetermined tip angle ⁇ 3 with respect to the first surface 116a. ing.
  • the second surface 116b of the prism structure 116 is set so that the inclination angle ⁇ 4 with respect to the surface parallel to the first main surface 115b is equal over all the prism structures 116.
  • the tip angle ⁇ 3 of each prism structure 116 is set to 88 °
  • the inclination angle ⁇ 4 of the second surface 116b is set to 2 °.
  • the second surface 116b of the prism structure 116 functions as a reflecting surface that reflects the light L propagating inside.
  • the light L propagating through the light guide 115 is repeatedly reflected between the first main surface 115b and the second surface 116b of the prism structure 16, and the incident angle of the light L on the first main surface 115b is critical. When it becomes smaller than the corner, it is taken out to the external space and emitted upward through the prism sheet 14.
  • FIG. 7 is a cross-sectional view of the light source in the surface light source device of the present embodiment cut along the xy plane, and corresponds to FIG. 4A of the first embodiment.
  • the same components as those in FIG. 4A are denoted by the same reference numerals, and description thereof is omitted.
  • the light source 119 of the present embodiment includes an LED 17, a concave mirror 19, and a cylindrical lens 120 as shown in FIG.
  • the groove 110 is provided on the light exit surface 18 a of the cylindrical lens 18, and the LED 17 is inserted into the groove 110.
  • no groove is provided on the light exit surface 120a of the cylindrical lens 120.
  • the LED 17 is disposed on the light exit surface 120 a of the cylindrical lens 120.
  • the LED 17 may be fixed on the light emission surface 120a of the cylindrical lens 120 using an optical adhesive or the like, or may be fixed using another fixing member.
  • the LED 17 is disposed so that the focal point P of the concave mirror 19 and the cylindrical lens 120 is positioned on the light emitting surface 17a.
  • the surface light source device of the present embodiment it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles.
  • the process for forming a groove in the cylindrical lens 120 is not required, the light source unit can be easily manufactured.
  • FIG. 8 is a cross-sectional view of the light source in the surface light source device of the present embodiment cut along the xz plane, and corresponds to FIG. 4B of the first embodiment.
  • the same components as those in FIG. 4B are denoted by the same reference numerals, and description thereof is omitted.
  • the light source 123 of the present embodiment includes an LED 124, a concave mirror 19, and a cylindrical lens 125, as shown in FIG.
  • the groove 110 is provided so as to penetrate from the upper end to the lower end of the cylindrical lens 18, and the LED 17 is disposed over the entire groove 110.
  • the groove 26 provided in the cylindrical lens 125 does not penetrate from the upper end to the lower end of the cylindrical lens 125.
  • the groove 26 is provided in a part of the cylindrical lens 125 in the height direction, and the LED 124 is inserted into the groove 26. That is, the length (dimension in the z-axis direction) of the LED 124 is shorter than the height (dimension in the z-axis direction) of the cylindrical lens 125.
  • the surface light source device of the present embodiment it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles.
  • the length of the LED 124 is shorter than that of the first embodiment, the cost of the surface light source device can be reduced.
  • FIGS. 9A and 9B The basic configuration of the surface light source device of this embodiment is the same as that of the first embodiment, and the configuration of the light source is different from that of the first embodiment.
  • FIG. 9A is a perspective view showing a light source in the surface light source device of this embodiment, and corresponds to FIG. 3 of the first embodiment.
  • FIG. 9B is a cross-sectional view when the light source of the present embodiment is cut along the xy plane, and corresponds to FIG. 4A of the first embodiment.
  • 9A and 9B the same components as those in FIGS. 3 and 4A are denoted by the same reference numerals, and description thereof is omitted.
  • the light source 129 of the present embodiment includes the LED 17 and the concave mirror 130, and does not include a cylindrical lens. That is, an air layer is present in the present embodiment in the region where the cylindrical lens 18 between the LED 17 and the concave mirror 19 was present in the first embodiment. Therefore, the concave mirror 130 of the present embodiment is configured by a parabolic reflector.
  • the LED 17 is disposed so that the focal point P of the concave mirror 130 is positioned on the light emitting surface 17a, and is fixed using an arbitrary fixing member (not shown) or the like.
  • the surface light source device of the present embodiment it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles.
  • the cost of the surface light source device can be reduced by not using a cylindrical lens.
  • a surface light source device with high luminance can be provided.
  • FIG. 10 is a front view of the light source unit of the surface light source device of the present embodiment as viewed from the light incident surface (end surface) side of the light guide, and corresponds to FIG. 5 of the first embodiment.
  • the same components as those in FIG. 10 are identical to FIG. 10 in FIG. 10, the same components as those in FIG.
  • the light source unit 12 of the first embodiment has a configuration in which a plurality of light sources 16 are arranged in a line in a direction (y-axis direction) orthogonal to the light propagation direction.
  • the light source unit 132 of the present embodiment includes a light source group in which a plurality of light sources 133A and 133B are arranged in a direction (y-axis direction) orthogonal to the light propagation direction. Two rows are provided in the normal direction (z-axis direction) of the first main surface of the light body.
  • the plurality of light sources 133A and 133B constituting the light source group in one row include two types of light sources having different widths (dimensions in the arrangement direction) of the cylindrical lenses 134A and 134B.
  • the light source 133A having a large width of the cylindrical lens 134A and the light source 133B having a small width of the cylindrical lens 134B are alternately arranged.
  • a light source 133B having a small width of the cylindrical lens 134B is disposed above the light source 133A having a large width of the cylindrical lens 134A.
  • a light source 133A having a large width of the cylindrical lens 134A is disposed above the light source 133B having a small width of the cylindrical lens 134B.
  • the upper and lower light sources 133A and 133B at the same position are different in the width of the cylindrical lenses 134A and 134B, but the LEDs 17 are arranged on the same straight line. As the LED 17, one common LED may be used in the upper and lower rows, or separate LEDs may be used in the upper and lower rows.
  • the surface light source device of the present embodiment it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles.
  • the light sources 133A and 133B having different widths of the cylindrical lenses 134A and 134B are overlapped on the upper and lower sides, so that even if there is luminance unevenness between the central part and the peripheral part of each light source, as a whole Has an effect of reducing unevenness in luminance.
  • FIG. 11 is a front view of the light source unit of the surface light source device of the present embodiment as viewed from the light incident surface (end surface) side of the light guide, and corresponds to FIG. 5 of the first embodiment.
  • the same reference numerals are given to the same components as those in FIG.
  • the light source unit 137 of the present embodiment includes a light source group in which a plurality of light sources 138 are arranged in a direction (y-axis direction) orthogonal to the light propagation direction. Two rows are provided in the normal direction (z-axis direction).
  • the plurality of light sources 138 constituting one row of light source groups all have the same dimensions. That is, the cylindrical lenses 140 are all the same size.
  • the position of the boundary between two light sources 138 adjacent in the upper row corresponds to the position of the LED 139 in the lower row, and the position of the boundary between two light sources 138 adjacent in the lower row corresponds to the position of the LED 139 in the upper row.
  • the arrangement of the plurality of light sources 138 in the upper row and the arrangement of the plurality of light sources 138 in the lower row are: There is a 1 ⁇ 2 pitch shift. Accordingly, when the two upper and lower rows are combined, if the width (dimension in the y-axis direction) of the light source 138 is the same, the pitch of the LEDs 139 of the light source unit 137 of this embodiment is 1 of the pitch of the LEDs 17 of the light source unit 12 of the first embodiment. / 2.
  • the same effect as in the first embodiment that light having high directivity can be obtained in all azimuth angles can be obtained.
  • the pitch of the LEDs 139 is substantially narrowed, so that the effect of reducing luminance unevenness as a whole is obtained.
  • FIG. 12 is a perspective view showing the light source device of the present embodiment.
  • 13A is a cross-sectional view taken along line A-A ′ of FIG. 13B is a cross-sectional view taken along line B-B ′ of FIG.
  • the scale of the size may be varied depending on the component.
  • the light source device 21 of the present embodiment includes a light source unit 22, a concave mirror 23, and a half mirror 24 as shown in FIG.
  • the concave mirror 23 has a function of emitting light emitted from the light source unit 22 from the main surface as substantially parallel light on the reflecting surface.
  • the half mirror 24 has a mechanism that transmits a part of the light emitted from the light source unit 22 to be incident on the concave mirror 23, reflects the remaining light, changes the traveling direction, and then enters the concave mirror 23.
  • the light source unit 22 is an LED.
  • the concave mirror 23 includes a cylindrical lens 25 (concave lens) and a mirror 26.
  • the cylindrical lens 25 is made of a resin such as an acrylic resin.
  • the cylindrical lens 25 is a so-called plano-concave lens having one concave surface and the other flat surface. Looking at the cross-sectional shape of the cylindrical lens 25 cut along the xy plane in the figure, the curved surface 25b of the concave surface has a curved shape having a focal point P as shown in FIG. 13A. In the case of this embodiment, specifically, the cross-sectional shape of the curved surface 25b is parabolic.
  • the curved surface 25b has a linear shape as shown in FIG. 13B. That is, the curved surface 25b of the cylindrical lens 25 is a paraboloid that is curved in the xy plane and not curved in the xy plane.
  • a mirror 26 is provided along the curved surface 25 b of the cylindrical lens 25.
  • the mirror 26 is made of a metal film having a high light reflectivity such as aluminum or silver directly formed on the curved surface 25b of the cylindrical lens 25.
  • the shape of the mirror 26 is a paraboloid reflecting the shape of the curved surface 25b. Therefore, the focal position of the concave mirror 23 coincides with the focal position of the cylindrical lens 25.
  • the focal point is indicated by point P in FIG. 13A.
  • a configuration in which a mirror manufactured separately from the cylindrical lens, for example, a dielectric mirror formed in a resin may be bonded.
  • the half mirror 24 is composed of two half mirrors 24a and 24b that are installed in parallel to the z axis and inclined with respect to the xz plane. In this embodiment, it is assumed that each is inclined 45 ° with respect to the xz plane. As shown in FIGS. 14A to 14C, each half mirror has a structure in which a reflective portion 28 is formed on a transparent base material 27. In the present embodiment, the reflecting portion 28 covers 80% of the surface of the transparent substrate 27 so that the transmittance is 20% and the reflectance is 80%. The reflection unit 28 is disposed between the transparent base material 27 and the light source unit 22.
  • the reflective portion 28 may be formed of a metal film having a high light reflectance such as aluminum or silver on the transparent base material 27, or a separate body in which the reflective portion 28 is formed on another transparent base material. It is good also as a structure bonded together on the transparent base material 27.
  • FIG. 14A the shape of the reflecting portion 28 may be a dot shape as shown in FIG. 14A, a stripe shape as shown in FIG. 14B, or a wave shape as shown in FIG. 14C.
  • the half mirror is such that the focal point P of the concave mirror 23 is located at the midpoint of a straight line connecting the tangent line 24c of the half mirror 24a and the half mirror 24b and the center line 22c parallel to the x axis of the light source unit 22. 24 and the light source unit 22 are installed.
  • the light source unit 22 includes a general LED.
  • the light source unit 22 may include a white LED, a blue LED, an ultraviolet LED, and the like.
  • the light distribution of the LED is a Lambertian distribution in which the luminous intensity increases in the front direction and decreases as the polar angle increases.
  • the light emitting main surface 22a faces the concave mirror 23 side, and most of the light emitted from the LED is applied to the concave mirror 23 or the half mirror 24. More specifically, of the light emitted from the LED, light having a large polar angle is directly incident on the concave mirror 23, and light having a small polar angle is incident on the concave mirror 23 after being transmitted or reflected by the half mirror 24. .
  • the light reflected by the half mirror 24 has a large polar angle and is irradiated to a region far from the center of the concave mirror 23.
  • both the light source unit 22 and the half mirror 24 are located in the vicinity of the focal point P of the concave mirror 23, neither the light directly incident on the concave mirror from the light source unit 22 nor the light transmitted or reflected by the half mirror 24 is concave mirror 23. And is emitted with directivity in a direction substantially parallel to the xz plane.
  • the emitted light beam from the light source unit be larger at the higher angle side and smaller in the front direction.
  • a general LED on the other hand, has a large emission light beam in the front direction and a small high angle side. Therefore, when it is incident on the concave mirror 23 as it is, the portion closer to the light source portion becomes brighter and the outer portion becomes darker.
  • the half mirror 24 by reflecting a part of the light beam emitted in the front direction by the half mirror 24 to the high angle side, it becomes possible to emit the emitted light uniformly within the surface while maintaining high directivity. Become.
  • an air layer exists between the concave mirror 23 and the light source unit 22, but the present embodiment is not limited to this configuration.
  • the cylindrical lens 18 of the first embodiment may be provided.
  • the half mirror 24 may be fixed by the cylindrical lens 18.
  • FIG. 15 is a cross-sectional view of the surface light source device of the present embodiment cut along the xy plane, and corresponds to FIG. 13A of the eighth embodiment.
  • the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
  • the mirror 29 is installed on a straight line connecting the tangent line 24 c of the half mirror 24 a and the half mirror 24 b and the center line 22 c parallel to the x axis of the light source unit 22.
  • FIG. 16 is a perspective view of the light source device of the present embodiment and corresponds to FIG. 12 of the eighth embodiment.
  • the same components as those in FIGS. 12 and 15 are denoted by the same reference numerals, and description thereof is omitted.
  • the mirror 210 is installed on five surrounding surfaces other than the exit surface of the concave mirror 23.
  • the mirror 210 By installing the mirror 210, the light that is emitted from the light source unit 22 and does not directly hit the concave mirror 23 is reflected and applied to the concave mirror 23, and the extraction efficiency from the concave mirror with respect to the total luminous flux emitted from the light source unit 22 It becomes possible to improve.
  • the concave mirror 23 and the mirror 210 may be integrally formed. [Eleventh embodiment]
  • FIG. 17 is a perspective view of the light source device of the present embodiment, and corresponds to FIG. 12 of the eighth embodiment.
  • FIG. 18 is a diagram corresponding to FIG. 13A of the eighth embodiment. 17 and 18, the same reference numerals are given to the same components as those in FIGS. 12 and 13A, and description thereof is omitted.
  • the shape of the concave mirror is changed to a concave mirror 23A having a shape cut by a plane passing through the mirror 29 with respect to the shape of the ninth embodiment. That is, the concave mirror 23A in the present embodiment has a shape obtained by cutting the concave mirror 23 in the ninth embodiment along a plane that passes through the axis of symmetry of the concave mirror 23. A mirror 211 is newly installed on the cut surface. Although the concave mirror is halved, the light beam emitted from the light source unit 22 is folded back by the mirror 211 and hits the concave mirror 23A. Therefore, the same effect as in the ninth embodiment can be obtained.
  • the present inventors performed an optical simulation regarding the luminance-angle profile and luminance-space profile of light emitted from the concave mirror.
  • the radius of curvature of the concave mirror 23 is 2.0 mm
  • the width of the concave mirror 23 in the y direction is 4.0 mm
  • the width of the light source unit 22 in the y direction is 0.2 mm
  • the length of the half mirror 24 is 0.283 mm
  • the half mirror Ray tracing simulation by the Monte Carlo method where the angle formed by 24 and the xz plane is 45 °
  • the distance between the light exit surface of the light source unit 22 and the focal point P the distance between the contact point of the half mirror 24 and the mirror 29 and the focal point P is 0.1 mm.
  • FIG. 8A shows a luminance-angle profile when the half mirror 29 is not provided and the light exit surface of the light source unit 22 is at the focal position
  • FIG. 8B shows a luminance-angle profile according to this embodiment
  • FIG. 8B is the luminance-space profile of the present embodiment.
  • the uniformity of spatial luminance is greatly improved over the comparison with FIG. 9A and FIG. This proves the effectiveness of the present embodiment.
  • FIG. 21 is a diagram corresponding to FIG. 13A of the first embodiment.
  • the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
  • the light source unit 22A is composed of a pair of back-to-back LEDs 22a and 22b each having an exit surface in a direction perpendicular to the xz plane, and each of the half mirror 24a and the half mirror 24b has an angle with the xy plane. It is installed. Unlike the first embodiment, since the front direction of the light emitting surface where the emitted light flux of the LED 22a and the LED 22b is large is directed to the high angle side, the ratio of the transmission portions of the half mirror 24a and the half mirror 24b is increased. The same effect can be obtained. [Thirteenth embodiment]
  • FIGS. 22, 23A and 23B The basic configuration of the light source device of the present embodiment is the same as that of the eighth embodiment. Even if the concave mirror 23B is cut along any plane that passes through the central axis and is orthogonal to the xy plane, it has a curved shape, for example, a parabolic shape. At the same time, the half mirror 24B is also conical.
  • FIG. 22 is a perspective view of the light source device of the present embodiment, and corresponds to FIG. 12 of the eighth embodiment.
  • FIG. 23A is a figure equivalent to FIG. 13A of 1st Embodiment
  • FIG. 23B is a figure corresponded to FIG. 13B of 1st Embodiment, and attaches
  • the concave mirror 23B has a curved surface shape, for example, a parabolic shape, even if cut by any plane that passes through the central axis and is orthogonal to the xy plane.
  • the half mirror 24B has a conical shape.
  • the eighth embodiment has directivity in a direction substantially parallel to the xz plane, and is diffused in the direction perpendicular thereto, and light is emitted. In the present embodiment, the light is emitted in a direction substantially perpendicular to the yz plane. It is possible to emit light having a high directivity at all azimuth angles. [Fourteenth embodiment]
  • FIG. 24 is a perspective view of the light source device of the present embodiment and corresponds to FIG. 12 of the eighth embodiment.
  • FIG. 25 is a diagram corresponding to FIG. 13A of the eighth embodiment, and common components are denoted by the same reference numerals and description thereof is omitted.
  • the emission part of the light source part 22C is parallel to the xy plane, and the emitted light enters the telecentric lens 212 and is emitted in a direction perpendicular to the xy plane.
  • the light emitted from the telecentric lens 212 is reflected or transmitted by the half mirror 24 and then emitted by the concave mirror 23 with directivity in a direction parallel to the xz plane.
  • the area of the light source unit 22C in a plane parallel to the light exit surface of the light source device 221 is small, it is difficult to shadow the light source unit 22C. Further, there is a feature that it is easy to provide a heat dissipation mechanism on the lower surface of the light source unit 22C and to be easily cooled.
  • Surfaces other than the entrance and exit of the telecentric lens 212 may be a reflector covered with a highly reflective metal film such as aluminum or silver. Further, the half mirror 24 and the telecentric lens 212 may be integrally formed. [Fifteenth embodiment]
  • FIG. 26 is a diagram corresponding to FIG. 13A of the eighth embodiment.
  • the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
  • a lens 243 is installed on the back surface of the light source unit 22, and the curvature of the lens 243 is adjusted so that the spread of light emitted from the concave mirror 23 is closer to parallel light. By installing the lens 243, emitted light having higher directivity can be obtained.
  • FIG. 27 is a diagram corresponding to FIG. 13A of the eighth embodiment.
  • the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
  • a lens 244 is installed on the front surface of the light source unit 22.
  • the lens 244 has a curved surface that can be approximated by a quartic function, and changes the traveling direction of light emitted in the front direction of the light source unit 22 to the high angle side. This makes it possible to emit the emitted light uniformly within the surface while maintaining high directivity.
  • FIG. 28 is a perspective view showing the surface light source device of this embodiment.
  • FIG. 29 is a cross-sectional view taken along line A-A ′ of FIG. 28 and 29, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.
  • the surface light source device 213 includes a light source device 21, a light guide 13, and a prism sheet 14 (direction changing member, direction changing member). Yes.
  • the light guide 13 has a function of causing light emitted from the light source device 21 to enter from the end face and to be emitted from the main surface while propagating inside.
  • the prism sheet 14 has a function of changing the traveling direction of the light emitted from the main surface of the light guide 13 to a direction closer to the normal line of the main surface.
  • the light source device 21 is a light source device having the same configuration as that of the eighth embodiment.
  • the operation of the surface light source device 213 configured as described above will be described.
  • a part of the light L emitted from the light source unit 22 is directly incident on the concave mirror 23, and part of the light L is incident on the concave mirror 23 after being transmitted or reflected by the half mirror 24, both of which are parallel to the xz plane. Is injected with directivity. On the other hand, there is no directivity in a direction parallel to the xy plane.
  • the light L incident on the light guide 13 from the light incident end surface 13a is between the first main surface 13b (light emission surface) and the second main surface 13c (reflection surface).
  • the light guide 13 travels in the light propagation direction X (right side in FIG.
  • the light guide 13 has a wedge shape in which the thickness gradually decreases as the distance from the light incident end surface 13a increases, and the second main surface 13c has a predetermined inclination angle with respect to the first main surface 13b.
  • the incident angle on the first main surface 13b and the second main surface 13c becomes small.
  • the critical angle on the first main surface 13b (light emission surface) of the light guide 13 is shown. That is, the critical angle at the interface between the acrylic resin constituting the light guide 13 and the air is about 42 ° from Snell's law.
  • the total reflection condition is satisfied as long as the incident angle of the light L on the first main surface 13b is larger than 42 ° which is a critical angle. Therefore, the light L is totally reflected by the first main surface 13b.
  • the incident angle of the light L on the first main surface 13b becomes smaller than 42 ° which is a critical angle.
  • the light L is emitted to the external space because the total reflection condition is not satisfied.
  • the light L is confined inside the light guide 13 while the incident angle on the first main surface 13b is larger than the critical angle, and the incident angle on the first main surface 13b becomes smaller than the critical angle.
  • the first main surface 13b is sequentially ejected. Since the light L is refracted when emitted from the first main surface 13b, light having an incident angle of about 42 ° to the first main surface 13b is emitted as light having an emission angle of about 70 °.
  • the light L is directional at the point of incidence on the light guide 13.
  • it has high directivity.
  • the emission angle of the light L when emitted from the light guide 13 is about 70 °, and the light L is emitted in a substantially horizontal direction. Therefore, it is necessary to use the prism sheet 14 to raise the light L emitted from the light guide 13 in a direction close to the normal direction of the first main surface 13 b of the light guide 13.
  • a prism sheet 14 having a prism structure 111 with a tip angle ⁇ 2 of about 38.5 ° is used, and light L is incident from the first surface 111a of the prism structure 111 and reflected by the second surface 111b. By doing so, the light guide 13 can be raised in a substantially normal direction with respect to the first main surface 13b.
  • the light emitted from the light source unit 22 is partially transmitted or reflected by the half mirror 24 and then reflected by the concave mirror 23, whereby the light emitting surface 13b of the light guide 13 is obtained.
  • the light guide 13 After having high directivity in a plane parallel to (xy plane), the light guide 13 is transmitted, so that it is parallel to the light propagation direction X and perpendicular to the light exit surface 13 b of the light guide 13.
  • High directivity can be provided even in a plane (xz plane).
  • light having high directivity can be extracted in the normal direction of the first main surface 13 b of the light guide 13 by transmitting the light through the prism sheet 14. As a result, light having high directivity at all azimuth angles can be obtained.
  • the present embodiment is an example of a liquid crystal display device provided with a modification of the surface light source device of the fifteenth embodiment as a backlight.
  • Constituent elements common to FIGS. 12 and 29 are denoted by the same reference numerals, and description thereof is omitted.
  • all the light source units 22 are installed with the light emitting main surface 22a facing the concave mirror 23.
  • the light source unit 239 is installed back-to-back with the light source unit 22 as shown in FIG. To do.
  • the light emission main surface 239 a of the light source unit 239 is disposed so as to face the light guide 13. The light emitted from the light source unit 239 enters the light guide 13 directly without hitting the concave mirror 23.
  • the light emitted from the light source unit 22 is emitted from the light guide 13 with directivity in all directions as described in the seventeenth embodiment, whereas the light emitted from the light source unit 239 is It has directivity only in a direction parallel to the yz plane, diffuses in the direction parallel to the xz plane, and is emitted from the light guide 13.
  • the directivity of the emitted light can be switched by switching between the light source unit 22 and the light source unit 239.
  • the light source unit 239 is also turned on, and it is possible to selectively use light emitted from multiple viewpoints.
  • the liquid crystal panel 240 for example, an active matrix transmissive liquid crystal panel can be used.
  • the liquid crystal panel is not limited to the active matrix type transmissive liquid crystal panel.
  • each pixel does not include a switching thin film transistor (Thin Film Transistor, hereinafter abbreviated as TFT).
  • TFT Thin Film Transistor
  • a simple matrix type liquid crystal panel may be used. Since a well-known general liquid crystal panel can be used for the liquid crystal panel 240, detailed description of the configuration is omitted. However, especially when the liquid crystal panel 240 is a liquid crystal panel such as an IPS system or an FFS system, where the initial liquid crystal alignment is parallel to the substrate and is switched by an electric field applied in a parallel direction, This is very effective because an image with little color misregistration can be viewed.
  • the light source unit 239 is installed back-to-back with the light source unit 22.
  • the light emission main surface 239a only needs to face the light guide 13, and is disposed, for example, in the vicinity of the boundary between adjacent concave mirrors 23. It doesn't matter.
  • FIG. 32 An example of a liquid crystal display device provided with the surface light source device of the seventeenth embodiment as a backlight. Is shown in FIG. 32
  • the liquid crystal display device 143 of this embodiment includes a backlight 144 (surface light source device), a first polarizing plate 145, a liquid crystal panel 146, a second polarizing plate 147, and a viewing angle widening film. 148.
  • the liquid crystal panel 146 is schematically illustrated as a single plate. The observer views the display from the upper side of the liquid crystal display device 143 in FIG. 32 where the viewing angle widening film 148 is arranged. Therefore, in the following description, the side on which the viewing angle widening film 148 is disposed is referred to as a viewing side, and the side on which the backlight 144 is disposed is referred to as a back side.
  • a liquid crystal display device 226 illustrated in FIG. 33 has a configuration similar to that of the liquid crystal display device 143, and is different in that a backlight 218 is provided instead of the backlight 144.
  • the light emitted from the backlight 144 is modulated by the liquid crystal panel 146, and a predetermined image, characters, or the like is displayed by the modulated light.
  • the liquid crystal display device 2266 light emitted from the backlight 218 is modulated by the liquid crystal panel 146, and a predetermined image, characters, or the like is displayed by the modulated light.
  • the angle distribution of the emitted light becomes wider than before entering the viewing angle widening film 148, and the light is widened. Is injected from. Thereby, the observer can visually recognize the display with a wide viewing angle.
  • the liquid crystal panel 146 for example, an active matrix transmissive liquid crystal panel can be used.
  • the liquid crystal panel is not limited to the active matrix type transmissive liquid crystal panel.
  • each pixel does not include a switching thin film transistor (Thin Film Transistor, hereinafter abbreviated as TFT).
  • TFT Thin Film Transistor
  • a simple matrix type liquid crystal panel may be used. Since a known general liquid crystal panel can be used as the liquid crystal panel 146, a detailed description of the configuration is omitted.
  • a viewing angle widening film 148 is disposed on the viewing side of the liquid crystal display device 143 and the liquid crystal display device 226.
  • the viewing angle widening film 148 includes a base material 149, a plurality of light diffusion portions 150 formed on one surface of the base material 149 (surface opposite to the viewing side), and a black layer 151 formed on one surface of the base material 149. (Light absorption layer).
  • the viewing angle widening film 148 is disposed on the second polarizing plate 147 in such a posture that the side where the light diffusion unit 150 is provided faces the second polarizing plate 147 and the base 149 side faces the viewing side.
  • the base material 149 for example, a base material made of a transparent resin such as a triacetyl cellulose (TAC) film is preferably used.
  • the light diffusing unit 150 is made of an organic material having optical transparency and photosensitivity such as acrylic resin and epoxy resin.
  • the light diffusing unit 150 has a circular horizontal cross section (xy cross section), has a small surface area on the base material 149 side serving as a light emission end face, and an area of a surface opposite to the base material 149 serving as a light incident surface. The area of the horizontal cross section gradually increases from the base material 149 side to the side opposite to the base material 149.
  • the light diffusing unit 150 when viewed from the base material 149 side, the light diffusing unit 150 has a so-called reverse-tapered truncated cone shape.
  • the light diffusion part 150 is a part that contributes to the transmission of light in the viewing angle widening film 148. That is, light incident on the light diffusing unit 150 is totally reflected by the tapered side surface of the light diffusing unit 150, guided in a state of being substantially confined inside the light diffusing unit 150, and diffused in all directions. It is injected at.
  • the black layer 151 is formed in a region other than the formation region of the plurality of light diffusion portions 150 on the surface of the base material 149 on the side where the light diffusion portions 150 are formed.
  • the black layer 151 is made of an organic material having light absorption and photosensitivity such as a black resist.
  • the screen is not displayed in a liquid crystal display device using a conventional backlight having no directivity. Color misregistration occurs when viewed from the front direction and when viewed from the oblique direction.
  • the backlight 144 which consists of the surface light source device of 1st Embodiment which has high directivity in a front direction is used.
  • the liquid crystal display device 226 uses the backlight 218 made up of the surface light source device of the seventeenth embodiment having high directivity in the front direction. Therefore, the liquid crystal panel 146 transmits only the angle range with little color change. Thereafter, since the light is diffused in all directions by the viewing angle widening film 148, the observer can see a high-quality image with little color shift from any direction.
  • FIG. 34 an example of a fluorescence excitation type liquid crystal display device provided with the surface light source device of the first embodiment as a backlight is shown in FIG. 34, and the fluorescence provided with the surface light source device of the 17th embodiment as a backlight.
  • FIG. 34 An example of an excitation type liquid crystal display device is shown in FIG. 34
  • the liquid crystal display device 154 of this embodiment includes a backlight 144 (a surface light source device), a liquid crystal element 155, and a light emitting element 156.
  • a red subpixel 157R for displaying with red light a green subpixel 157G for displaying with green light
  • a blue subpixel 157B for displaying with blue light are arranged adjacent to each other.
  • These three sub-pixels 157R, 157G, and 157B constitute one pixel that is a minimum unit that constitutes a display.
  • a liquid crystal display device 227 illustrated in FIG. 35 has a configuration similar to that of the liquid crystal display device 154, and is different in that a backlight 218 is provided instead of the backlight 144.
  • the backlights 144 and 218 emit excitation light L1 that excites the phosphor layers 158R, 158G, and 158B of the light emitting element 156.
  • the backlights 144 and 218 emit ultraviolet light or blue light as the excitation light L1.
  • the liquid crystal element 155 modulates the transmittance of the excitation light L1 emitted from the backlight 144 for each of the subpixels 157R, 157G, and 157B. Excitation light L1 modulated by the liquid crystal element 155 is incident on the light emitting element 156, and the phosphor layers 158R, 158G, and 158B are excited and emitted light is emitted to the outside. Therefore, in the present embodiment, the upper side of the liquid crystal display device 154 shown in FIG. 13 is the viewing side on which the observer views the display.
  • the liquid crystal element 155 has a configuration in which a liquid crystal layer 161 is sandwiched between a first transparent substrate 159 and a second transparent substrate 160.
  • the second transparent substrate 160 located on the front side as viewed from the observer also serves as a substrate of the light emitting element.
  • a first transparent electrode 162 is formed for each subpixel, and an alignment film (not shown) is formed so as to cover the first transparent electrode 162.
  • a first polarizing plate 163 is provided on the outer surface of the first transparent substrate 159 (the surface opposite to the liquid crystal layer 161 side).
  • the first transparent substrate 159 a substrate made of glass, quartz, plastic, or the like that can transmit excitation light can be used.
  • a transparent conductive material such as indium tin oxide (Indium Tin Oxide, hereinafter abbreviated as ITO) is used.
  • ITO Indium Tin Oxide
  • the first polarizing plate 163 a conventional general external polarizing plate can be used.
  • a phosphor layer 158 and a first light absorption layer 164 are laminated in this order from the substrate side on the inner surface (the surface on the liquid crystal layer 161 side) of the second transparent substrate 160.
  • the phosphor material constituting the phosphor layer 158 has a different emission wavelength band for each subpixel.
  • the red subpixel 157R is provided with a phosphor layer 158R made of a phosphor material that absorbs ultraviolet light and emits red light.
  • the green subpixel 157G is provided with a phosphor layer 158G made of a phosphor material that absorbs ultraviolet light and emits green light.
  • the blue subpixel 157B is provided with a phosphor layer 158B made of a phosphor material that absorbs ultraviolet light and emits blue light.
  • the red subpixel 157R and the green subpixel 157G absorb the blue light and emit red light and green light respectively.
  • Phosphor layers 158R and 158G made of a material are provided, and instead of the phosphor layer, the blue subpixel 157B diffuses the blue light as excitation light without converting the wavelength and emits the light to the outside. Is provided.
  • a second polarizing plate 165 is formed on the inner surface of the second transparent substrate 160 so as to cover the light absorption layer 164, and a second transparent electrode 166 and an alignment film (not shown) are formed on the surface of the second polarizing plate 165. Are stacked.
  • the second polarizing plate 165 is a so-called in-cell polarizing plate that is formed using a coating technique or the like in the manufacturing process of the liquid crystal element 155.
  • a transparent conductive material such as ITO is used as in the case of the first transparent electrode 162.
  • a second light absorption layer 167 is formed on the outer surface side of the second transparent substrate 160.
  • the first light absorption layer 164 provided on the inner surface of the second transparent substrate 160 is for suppressing a decrease in contrast due to leakage of the excitation light L1 from the backlights 144 and 218.
  • the second light absorption layer 167 provided on the outer surface of the second transparent substrate 160 is for suppressing a decrease in contrast due to external light.
  • an ordinary liquid crystal display device has a color shift when viewed from an oblique direction.
  • the fluorescence excitation type liquid crystal display device 154 of the present embodiment uses an ultraviolet light or blue light surface light source device having high directivity as the backlight 144 and uses the ultraviolet light or blue light as the phosphor layer 158. Color conversion.
  • the liquid crystal display device 227 uses an ultraviolet light or blue light surface light source device having high directivity as the backlight 218, and converts the color of the ultraviolet light or blue light by the phosphor layer 158. At this time, since the light of each color is isotropically emitted from the phosphor layer 158, the observer can see a high-quality image with little color shift from any direction.
  • FIG. 36 is a front view showing a schematic configuration of a liquid crystal display device which is one configuration example of the display device.
  • the liquid crystal television 175 of this configuration example includes the liquid crystal display device 143, 226, 154, or 227 of the nineteenth or twentieth embodiment as a display screen.
  • a liquid crystal panel is disposed on the viewer side (front side in FIG. 36), and a backlight (surface light source device) is disposed on the side opposite to the viewer (back side in FIG. 36).
  • the liquid crystal television 175 of this configuration example includes the liquid crystal display device 143, 226, 154, or 227 of the above embodiment, and thus becomes a high quality liquid crystal television.
  • FIGS. 37 and 38 are diagrams showing a schematic configuration of the illumination device.
  • the basic configuration of the illumination device shown in FIG. 37 is substantially the same as that of the surface light source device of the first embodiment. Therefore, in FIG. 37, the same components as those in FIG. Is omitted.
  • the same reference numerals in FIG. 38 denote the same components as in FIG. 29 of the seventeenth embodiment. The description is omitted.
  • the illumination device 176 of this configuration example includes a light source unit 12 and a light guide 13. That is, the illumination device 176 is obtained by removing the prism sheet from the surface light source device of the first embodiment shown in FIG. Since the illuminating device 176 does not include a prism sheet, the light emitted from the illuminating device 176 does not rise in the normal direction of the first main surface 13b (light emission surface) of the light guide 13 and rises to the first main surface 13b. On the other hand, it is injected at a large injection angle. Accordingly, as shown in FIG.
  • the illumination device 242 illustrated in FIG. 38 has a configuration similar to that of the illumination device 176, and is different in that the light source unit 21 is provided instead of the light source unit 12.
  • the lighting device 176 or 242 of this configuration example is installed near the ceiling of a hall, for example, light with high directivity is emitted downward from the lighting device 176 or 242 and can be used as a spotlight.
  • the shape of the concave mirror is a paraboloid.
  • the shape of the concave mirror that can be used in the above embodiment is not necessarily limited to a paraboloid, and may be a conical curved surface as a concept including a paraboloid.
  • a curve indicating the shape of a cross section passing through the apex of the conical curved surface is called a quadratic curve.
  • a quadratic curve is a curve obtained from a cross section obtained by cutting a cone at an arbitrary plane.
  • the quadratic curve can be expressed by the following equations (1) and (2).
  • the shape of the quadratic curve changes depending on the value of the conic coefficient k in the equations (1) and (2).
  • the region where the light from the LED reaches may be at least a conical curved surface, and the region where the light from the LED does not reach may be, for example, a flat surface.
  • the aspect of the present invention can be used for various display devices such as liquid crystal display devices, organic electroluminescence display devices, plasma displays, surface light source devices used in these display devices, or various illumination devices.
  • display devices such as liquid crystal display devices, organic electroluminescence display devices, plasma displays, surface light source devices used in these display devices, or various illumination devices.
  • the aspect of the present invention can be used for various display devices having a shutter function such as a liquid crystal display device and MEMS, a surface light source device used for these display devices, or various illumination devices.

Abstract

This surface light source device comprises a light source and a light guide body. The light source has at least a light-emitting element having a light-emitting surface and a concave mirror for reflecting the light emitted from the light-emitting element. The light guide body has an end surface from which light emitted from the light source is incident, and a primary surface from which the light, having propagated within the interior, is emitted. At least a part of the cross-sectional shape of the concave mirror when cut in a plane parallel to the primary surface of the light guide body has a curved shape having a focus point. The light-emitting element is disposed such that the focus point is located on the light-emitting surface. The light from the light-emitting element is incident on the light guide body via the concave mirror.

Description

光源装置、面光源装置、表示装置および照明装置Light source device, surface light source device, display device, and illumination device
　本発明は、光源装置、面光源装置、表示装置および照明装置に関する。
　本願は、２０１１年４月２８日に日本に出願された特願２０１１－１０２４０４号、及び２０１１年５月１３日に日本に出願された特願２０１１－１０７７１８に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a light source device, a surface light source device, a display device, and an illumination device.
This application claims priority based on Japanese Patent Application No. 2011-102404 filed in Japan on April 28, 2011 and Japanese Patent Application No. 2011-107718 filed in Japan on May 13, 2011. Is hereby incorporated by reference.
表示装置の一例として、面光源装置から射出される光を利用して表示を行う透過型液晶表示装置が知られている。この種の液晶表示装置は、液晶パネルと、液晶パネルの背面側に配置された面光源装置と、を有している。従来の面光源装置は、発光ダイオード（Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ， 以下、ＬＥＤと略記する）等の光源と導光板とを備え、光源から射出された光を導光板の内部で伝播させ、導光板の全面から射出させるのが一般的である。以下、本明細書では、表示パネルの背面側に設けられる面光源装置のことをバックライトと記す場合もある。 As an example of a display device, a transmissive liquid crystal display device that performs display using light emitted from a surface light source device is known. This type of liquid crystal display device has a liquid crystal panel and a surface light source device disposed on the back side of the liquid crystal panel. A conventional surface light source device includes a light source such as a light emitting diode (hereinafter abbreviated as “LED”) and a light guide plate, and propagates light emitted from the light source inside the light guide plate. It is common to inject from. Hereinafter, in this specification, the surface light source device provided on the back side of the display panel may be referred to as a backlight.
　また、光源装置の一例として、ＬＥＤ等の光源と、ＬＥＤからの光を反射させるリフレクターとを有する反射型光源装置が知られている。リフレクターは軸を中心に放物面を回転させた形状を有している。また、ＬＥＤの発光点は、リフレクターの放物面の焦点に位置しており、ＬＥＤからの光はリフレクターで反射され、高い指向性を持って射出される。 Also, as an example of a light source device, a reflection type light source device having a light source such as an LED and a reflector that reflects light from the LED is known. The reflector has a shape obtained by rotating the paraboloid around the axis. The light emitting point of the LED is located at the focal point of the paraboloid of the reflector, and the light from the LED is reflected by the reflector and emitted with high directivity.
　下記の特許文献１には、複数の光源装置と、これら光源装置が端面に配置された導光板と、を備えたバックライト装置が開示されている。このバックライト装置において、光源装置は、ＬＥＤと、ＬＥＤからの光を反射させるリフレクターと、を備えている。リフレクターは、放物面をその軸線を通る水平面で半分に割った形状を有している。また、ＬＥＤの発光点は、リフレクターの放物面の焦点に位置している。 The following Patent Document 1 discloses a backlight device including a plurality of light source devices and a light guide plate in which these light source devices are arranged on an end surface. In this backlight device, the light source device includes an LED and a reflector that reflects light from the LED. The reflector has a shape in which the paraboloid is divided in half by a horizontal plane passing through its axis. The light emitting point of the LED is located at the focal point of the paraboloid of the reflector.
特開２００７－２３４３８５号公報JP 2007-234385 A 特開２０１０－８７０１５号公報JP 2010-87015 A
　特許文献１に記載されたバックライト装置において、ＬＥＤから射出された光の一部は、リフレクターで反射することなく導光板に入射される。そのため、指向性の高い光が得られない。 In the backlight device described in Patent Document 1, a part of the light emitted from the LED is incident on the light guide plate without being reflected by the reflector. Therefore, light with high directivity cannot be obtained.
　特許文献２に記載された光源装置において、ＬＥＤの配光分布が一般的なランバート分布となっている。光源装置において、正面方向ほど光度が大きく、極角が大きくなるにつれて光度が小さくなる場合、リフレクターで反射された後の面内照度分布は中心に近いほど明るく、リフレクターの外周に近いほど暗い不均一な分布となる。この面内輝度分布が不均一な光源を例えば液晶表示装置の表示パネルの背面側に設けられる面光源（以下、バックライト）の入光用光源として用いる場合、発光面内の輝度ムラの発生する要因となり、液晶表示装置の画像が正しく表示できない。 In the light source device described in Patent Document 2, the light distribution of LEDs is a general Lambertian distribution. In the light source device, when the luminous intensity increases toward the front and decreases as the polar angle increases, the in-plane illuminance distribution after being reflected by the reflector is brighter as it is closer to the center and darker as it is closer to the outer periphery of the reflector. Distribution. When using a light source with a non-uniform in-plane luminance distribution as an incident light source for a surface light source (hereinafter referred to as a backlight) provided on the back side of a display panel of a liquid crystal display device, for example, uneven brightness occurs in the light emitting surface. As a result, the image of the liquid crystal display device cannot be displayed correctly.
　本発明の態様は、上記の課題を解決するためになされたものであって、指向性の高い光が得られる面光源装置を提供することを目的とする。また、この種の面光源装置を備えた表示装置および照明装置を提供することを目的とする。 An aspect of the present invention has been made to solve the above-described problem, and an object thereof is to provide a surface light source device that can obtain light with high directivity. Moreover, it aims at providing the display apparatus and illuminating device provided with this kind of surface light source device.
　また、本発明の態様は、上記の光源装置の面内照度不均一性に起因する課題を解決するためになされたものであって、指向性の高い光が得られ、かつ面内分布が均一な光源装置を提供することを目的とする。また、この種の光源装置を備えた表示装置および照明装置を提供することを目的とする。 In addition, an aspect of the present invention is made to solve the problem caused by the in-plane illuminance non-uniformity of the above-described light source device, and can obtain light with high directivity and uniform in-plane distribution. An object of the present invention is to provide a simple light source device. Moreover, it aims at providing the display apparatus and illuminating device provided with this kind of light source device.
　上記の目的を達成するために、本発明の一態様における面光源装置は、発光面を有する発光素子と前記発光素子から射出された光を反射する凹面ミラーとを少なくとも有する光源と、前記光源から射出された光を端面から入射させ、内部で伝播させて主面から射出させる導光体と、を備え、前記凹面ミラーは、前記導光体の主面に平行な平面で切断したときの断面形状が、焦点を有する曲線形状を少なくとも一部に有し、前記発光素子は、前記発光面上に前記焦点が位置するように配置されるとともに、前記発光素子からの光が、前記凹面ミラーを介して前記導光体に入射される構成を有する。 In order to achieve the above object, a surface light source device according to an aspect of the present invention includes a light source having at least a light emitting element having a light emitting surface and a concave mirror that reflects light emitted from the light emitting element, and the light source. A light guide that causes the emitted light to enter from the end face, propagate inside, and exit from the main surface, and the concave mirror is a cross-section taken along a plane parallel to the main surface of the light guide The shape has at least a part of a curved shape having a focal point, and the light emitting element is disposed such that the focal point is located on the light emitting surface, and light from the light emitting element is provided on the concave mirror. Via the light guide.
　本発明の面光源装置は、前記導光体が、前記光の伝播方向において前記主面に対して所定の傾斜角をなす反射面を有していてもよい。 In the surface light source device of the present invention, the light guide may have a reflecting surface that forms a predetermined inclination angle with respect to the main surface in the light propagation direction.
　本発明の一態様における面光源装置は、前記光源が、前記凹面ミラーの窪みに配置された凸レンズを備え、前記凸レンズの焦点の位置が前記凹面ミラーの焦点の位置と略一致していてもよい。 In the surface light source device according to one aspect of the present invention, the light source may include a convex lens disposed in a recess of the concave mirror, and the position of the focal point of the convex lens may substantially coincide with the position of the focal point of the concave mirror. .
　本発明の一態様における面光源装置は、前記凹面ミラーが、前記凸レンズの凸面に形成された金属膜で構成されていてもよい。 In the surface light source device according to one aspect of the present invention, the concave mirror may be formed of a metal film formed on the convex surface of the convex lens.
　本発明の一態様における面光源装置は、前記凸レンズの凸面と対向する面に溝が設けられ、前記溝の内部に前記発光素子が配置されていてもよい。 In the surface light source device according to an aspect of the present invention, a groove may be provided on a surface facing the convex surface of the convex lens, and the light emitting element may be disposed inside the groove.
　本発明の一態様における面光源装置は、前記導光体の主面に平行な平面で切断したときの前記溝の底部の断面形状が曲線状であってもよい。 In the surface light source device according to one aspect of the present invention, the cross-sectional shape of the bottom of the groove when cut along a plane parallel to the main surface of the light guide may be curved.
　本発明の一態様における面光源装置は、前記導光体の主面に垂直な平面で切断したときの前記凹面ミラーの断面形状が直線形状であってもよい。 In the surface light source device according to one aspect of the present invention, a cross-sectional shape of the concave mirror when cut along a plane perpendicular to the main surface of the light guide may be a linear shape.
　本発明の一態様における面光源装置は、前記導光体の端面に、前記光源が、前記主面に平行、かつ前記光の伝播方向に垂直な方向に複数並べて配置されていてもよい。 In the surface light source device according to one aspect of the present invention, a plurality of the light sources may be arranged on the end surface of the light guide in a direction parallel to the main surface and perpendicular to the light propagation direction.
　本発明の一態様における面光源装置は、前記複数の光源が、前記主面に垂直な方向に複数列並べて配置されていてもよい。 In the surface light source device according to one aspect of the present invention, the plurality of light sources may be arranged in a plurality of rows in a direction perpendicular to the main surface.
　本発明の一態様における面光源装置は、一つの列を構成する前記複数の光源において、前記凹面ミラーの配列方向の寸法が異なっていてもよい。 In the surface light source device according to one aspect of the present invention, the plurality of light sources forming one row may have different dimensions in the arrangement direction of the concave mirrors.
　本発明の一態様における面光源装置は、複数の列を構成する前記複数の光源において、前記光源の配列方向における前記発光素子の位置が列毎に異なっていてもよい。 In the surface light source device according to one aspect of the present invention, in the plurality of light sources constituting a plurality of columns, the positions of the light emitting elements in the arrangement direction of the light sources may be different for each column.
　本発明の一態様における面光源装置は、前記導光体が、前記端面に近い側から前記端面から遠い側に向けて厚みが薄くなる楔形状を有し、前記主面と対向する面全体が前記反射面であってもよい。 In the surface light source device according to one aspect of the present invention, the light guide has a wedge shape in which the thickness decreases from the side near the end surface toward the side far from the end surface, and the entire surface facing the main surface is The reflective surface may be used.
　本発明の一態様における面光源装置は、前記導光体が、前記主面と対向する面に複数のプリズム構造体を有し、前記プリズム構造体の一つの傾斜面が前記反射面であってもよい。 In the surface light source device according to one aspect of the present invention, the light guide has a plurality of prism structures on a surface facing the main surface, and one inclined surface of the prism structure is the reflection surface. Also good.
　本発明の一態様における面光源装置は、さらに、前記導光体の主面から射出された光の進行方向を、前記主面の法線により近い方向に変更する方向変更部材が備えられていてもよい。 The surface light source device according to one aspect of the present invention further includes a direction changing member that changes a traveling direction of light emitted from the main surface of the light guide to a direction closer to a normal line of the main surface. Also good.
　本発明の他の態様における表示装置は、上記面光源装置と、前記面光源装置から射出される光を用いて表示を行う表示素子と、を備える。 A display device according to another aspect of the present invention includes the above surface light source device and a display element that performs display using light emitted from the surface light source device.
　本発明のさらに他の態様における照明装置は、上記面光源装置を備える。 An illumination device according to still another aspect of the present invention includes the surface light source device.
　本発明のさらに他の態様における光源装置は、第１発光面を有する第１発光素子と、前記第１発光素子から射出された光を反射する凹面ミラーと、入射した光の少なくとも一部の進行方向を変える方向変更素子を備え、前記凹面ミラーは、前記発光面に平行な平面で切断したときの断面形状が、焦点を有する曲線形状を少なくとも一部に有し、前記焦点が、前記第１発光素子の前記第１発光面と方向変更素子のいずれか、もしくはそれらを結んだ線上に位置するように配置され、前記第１発光素子からの光の少なくとも一部が前記方向変更素子により進行方向を変更され、前記凹面ミラーを介して出射される構成を有する。 According to still another aspect of the present invention, a light source device includes a first light emitting element having a first light emitting surface, a concave mirror that reflects light emitted from the first light emitting element, and a progression of at least a part of incident light. The concave mirror includes a direction changing element for changing a direction, and the concave mirror has a curved shape having a focal point at least in part when cut along a plane parallel to the light emitting surface, and the focal point is the first The first light emitting surface of the light emitting element and any one of the direction changing elements, or a line connecting the first light emitting surface and the direction changing element, are arranged such that at least a part of the light from the first light emitting element travels in the traveling direction by the direction changing element. And is emitted through the concave mirror.
　本発明のさらに他の態様における光源装置は、前記方向変更素子が、入射した光の少なくとも一部を透過し、透過しなかった光を反射するハーフミラーであってもよい。 The light source device according to still another aspect of the present invention may be a half mirror in which the direction changing element transmits at least part of incident light and reflects light that has not been transmitted.
　本発明のさらに他の態様における光源装置は、前記曲線形状が放物面であってもよい。 In the light source device according to still another aspect of the present invention, the curved shape may be a paraboloid.
　本発明のさらに他の態様における光源装置は、さらに、前記第１発光素子と前記方向変更素子の間に配置されたミラーを備えていてもよい。 The light source device according to still another aspect of the present invention may further include a mirror disposed between the first light emitting element and the direction changing element.
　本発明のさらに他の態様における光源装置は、さらに、前記凹面ミラーの曲線形状以外の面を囲うように配置されたミラーを備えていてもよい。 The light source device according to still another aspect of the present invention may further include a mirror disposed so as to surround a surface other than the curved shape of the concave mirror.
　本発明のさらに他の態様における光源装置は、さらに、前記凹面ミラーが対称軸に沿って切断された曲線形状を有しており、対称軸上にミラーが設置されていてもよい。 In the light source device according to still another aspect of the present invention, the concave mirror may have a curved shape cut along the symmetry axis, and the mirror may be installed on the symmetry axis.
　本発明のさらに他の態様における光源装置は、前記凹面ミラーの曲線形状の中心軸を通るあらゆる平面で前記凹面ミラーを切断しても曲面形状を有していてもよい。 The light source device according to still another aspect of the present invention may have a curved surface shape even if the concave mirror is cut at any plane passing through the central axis of the curved shape of the concave mirror.
　本発明のさらに他の態様における光源装置は、前記方向変更素子が円錐形状を有していてもよい。 In the light source device according to still another aspect of the present invention, the direction changing element may have a conical shape.
　本発明のさらに他の態様における光源装置は、前記発光素子の発光主面が凹面ミラー側に向いていてもよい。 In the light source device according to still another aspect of the present invention, the light emitting main surface of the light emitting element may face the concave mirror side.
　本発明のさらに他の態様における光源装置は、前記第１発光面が前記凹面ミラーと対向していてもよい。 In the light source device according to still another aspect of the present invention, the first light emitting surface may face the concave mirror.
　本発明のさらに他の態様における光源装置は、前記第１発光面が前記凹面ミラーの曲線形状の中心軸に対して平行であってもよい。 In the light source device according to still another aspect of the present invention, the first light emitting surface may be parallel to a curved central axis of the concave mirror.
　本発明のさらに他の態様における光源装置は、前記第１発光素子が白色ＬＥＤであってもよい。 In the light source device according to still another aspect of the present invention, the first light emitting element may be a white LED.
　本発明のさらに他の態様における光源装置は、前記第１発光素子が青色ＬＥＤであってもよい。 In a light source device according to still another aspect of the present invention, the first light emitting element may be a blue LED.
　本発明のさらに他の態様における光源装置は、前記第１発光素子が紫外線ＬＥＤであってもよい。 In the light source device according to still another aspect of the present invention, the first light emitting element may be an ultraviolet LED.
　本発明のさらに他の態様における光源装置は、前記ハーフミラーが透明基材と、前記透明基材上に金属膜で形成された反射部によって形成されていてもよい。 In the light source device according to still another aspect of the present invention, the half mirror may be formed of a transparent base material and a reflective portion formed of a metal film on the transparent base material.
　本発明のさらに他の態様における光源装置は、前記反射部がドット形状をしていてもよい。 In the light source device according to still another aspect of the present invention, the reflecting portion may have a dot shape.
　本発明のさらに他の態様における光源装置は、前記反射部がストライプ形状をしていてもよい。 In the light source device according to still another aspect of the present invention, the reflecting portion may have a stripe shape.
　本発明のさらに他の態様における光源装置は、前記反射部が波状の形状をしていてもよい。 In the light source device according to still another aspect of the present invention, the reflecting portion may have a wave shape.
　本発明のさらに他の態様における面光源装置は、前記光源装置と、前記光源装置から射出された光を端面から入射させ、内部で伝播させて主面から射出させる導光体と、を備えている。 A surface light source device according to still another aspect of the present invention includes the light source device, and a light guide that causes light emitted from the light source device to enter from an end surface, propagate inside, and exit from a main surface. Yes.
　本発明のさらに他の態様における面光源装置は、前記導光体が、前記光の伝播方向において前記主面に対して所定の傾斜角をなす反射面を有していてもよい。 In the surface light source device according to still another aspect of the present invention, the light guide may have a reflective surface that forms a predetermined inclination angle with respect to the main surface in the light propagation direction.
　本発明のさらに他の態様における面光源装置は、前記導光体が前記端面に近い側から前記端面から遠い側に向けて厚みが薄くなる楔形状を有していてもよい。 In the surface light source device according to still another aspect of the present invention, the light guide may have a wedge shape whose thickness decreases from a side closer to the end surface toward a side farther from the end surface.
　本発明のさらに他の態様における面光源装置は、前記導光体の端面に、前記光源が、前記主面に平行、かつ前記光の伝播方向に垂直な方向に複数並べて配置されていてもよい。 In the surface light source device according to still another aspect of the present invention, a plurality of the light sources may be arranged on the end surface of the light guide in a direction parallel to the main surface and perpendicular to the light propagation direction. .
　本発明のさらに他の態様における面光源装置は、さらに、前記導光体の主面から射出された光の進行方向を、前記主面の法線により近い方向に変更する方向変更部材が備えられていてもよい。 The surface light source device according to still another aspect of the present invention further includes a direction changing member that changes a traveling direction of light emitted from the main surface of the light guide to a direction closer to a normal line of the main surface. It may be.
　本発明のさらに他の態様における表示装置は、前記面光源装置と、前記面光源装置から射出される光を用いて表示を行う表示素子と、を備える。 A display device according to still another aspect of the present invention includes the surface light source device and a display element that performs display using light emitted from the surface light source device.
　本発明のさらに他の態様における表示装置は、前記表示素子が視野角拡大フィルムを有する液晶パネルであってもよい。 The display device according to still another aspect of the present invention may be a liquid crystal panel in which the display element has a viewing angle widening film.
　本発明のさらに他の態様における表示装置は、前記表示素子が蛍光励起方式の液晶パネルであってもよい。 In a display device according to still another aspect of the present invention, the display element may be a fluorescence excitation type liquid crystal panel.
　本発明のさらに他の態様における面光源装置は、さらに、前記導光体と対向する第２に発光面を有する第２発光素子を有し、前記第１発光面が前記凹面ミラーと対向するよう前記第１発光素子が配置され、前記第２発光面が前記導光体と対向するよう前記第２発光素子が配置されていてもよい。 The surface light source device according to still another aspect of the present invention further includes a second light emitting element having a second light emitting surface facing the light guide, and the first light emitting surface faces the concave mirror. The first light emitting element may be disposed, and the second light emitting element may be disposed such that the second light emitting surface faces the light guide.
　本発明のさらに他の態様における表示装置は、前記面光源装置と、前記面光源装置から射出される光を用いて表示を行う表示素子と、を備える。 A display device according to still another aspect of the present invention includes the surface light source device and a display element that performs display using light emitted from the surface light source device.
　本発明のさらに他の態様における表示装置は、前記表示素子が、液晶配向が基板に対して平行で、平行方向に印加される電界によってスイッチングされる液晶パネルであってもよい。 In a display device according to still another aspect of the present invention, the display element may be a liquid crystal panel in which liquid crystal alignment is parallel to the substrate and is switched by an electric field applied in a parallel direction.
　本発明のさらに他の態様における光源装置は、前記発光素子の背面にレンズが設置されている。 In the light source device according to still another aspect of the present invention, a lens is installed on the back surface of the light emitting element.
　本発明のさらに他の態様における光源装置は、前記方向変更素子が、レンズであってもよい。 In the light source device according to still another aspect of the present invention, the direction changing element may be a lens.
　本発明のさらに他の態様における光源装置は、前記レンズが、４次関数で近似できる曲面を有していてもよい。 In the light source device according to still another aspect of the present invention, the lens may have a curved surface that can be approximated by a quartic function.
　本発明の態様によれば、指向性の高い光が得られる面光源装置を提供することができる。また、この種の面光源装置を備えた表示装置および照明装置を提供することができる。 According to the aspect of the present invention, it is possible to provide a surface light source device that can obtain light with high directivity. Moreover, a display apparatus and an illuminating device provided with this kind of surface light source device can be provided.
　また、本発明の態様によれば、指向性の高く、かつ面内の輝度均一性の高い射出光が得られる光源装置を提供することができる。また、この種の光源装置を備えた面光源装置、表示装置および照明装置を提供することができる。 Further, according to the aspect of the present invention, it is possible to provide a light source device capable of obtaining emitted light with high directivity and high in-plane luminance uniformity. In addition, a surface light source device, a display device, and an illumination device including this type of light source device can be provided.
本発明の第１実施形態の面光源装置を示す斜視図である。It is a perspective view which shows the surface light source device of 1st Embodiment of this invention. 図１のＡ－Ａ’線に沿う断面図である。FIG. 2 is a cross-sectional view taken along the line A-A ′ of FIG. 1. 本実施形態の面光源装置における一つの光源を示す斜視図である。It is a perspective view which shows one light source in the surface light source device of this embodiment. 図３のＢ－Ｂ’線に沿う断面図である。FIG. 4 is a sectional view taken along line B-B ′ of FIG. 3. 図３のＣ－Ｃ’線に沿う断面図である。FIG. 4 is a cross-sectional view taken along line C-C ′ of FIG. 3. 本実施形態の面光源装置における複数個の光源を示す正面図である。It is a front view which shows the some light source in the surface light source device of this embodiment. 本発明の第２実施形態の面光源装置を示す断面図である。It is sectional drawing which shows the surface light source device of 2nd Embodiment of this invention. 本発明の第３実施形態の面光源装置における一つの光源を示す断面図である。It is sectional drawing which shows one light source in the surface light source device of 3rd Embodiment of this invention. 本発明の第４実施形態の面光源装置における一つの光源を示す断面図である。It is sectional drawing which shows one light source in the surface light source device of 4th Embodiment of this invention. 本発明の第５実施形態の面光源装置における一つの光源を示す斜視図である。It is a perspective view which shows one light source in the surface light source device of 5th Embodiment of this invention. 本発明の第５実施形態の面光源装置における一つの光源を示す断面図である。It is sectional drawing which shows one light source in the surface light source device of 5th Embodiment of this invention. 本発明の第６実施形態の面光源装置における複数個の光源を示す正面図である。It is a front view which shows the some light source in the surface light source device of 6th Embodiment of this invention. 本発明の第７実施形態の面光源装置における複数個の光源を示す正面図である。It is a front view which shows the several light source in the surface light source device of 7th Embodiment of this invention. 本発明の第８実施形態の光源装置を示す斜視図である。It is a perspective view which shows the light source device of 8th Embodiment of this invention. 図１２のＡ－Ａ’線に沿う断面図である。FIG. 13 is a cross-sectional view taken along the line A-A ′ of FIG. 12. 図１２のＢ－Ｂ’線に沿う断面図である。FIG. 13 is a sectional view taken along line B-B ′ of FIG. 12. 本発明の第８実施形態のハーフミラーの反射部の形状図である。It is a shape figure of the reflection part of the half mirror of 8th Embodiment of this invention. 本発明の第８実施形態のハーフミラーの反射部の形状図である。It is a shape figure of the reflection part of the half mirror of 8th Embodiment of this invention. 本発明の第８実施形態のハーフミラーの反射部の形状図である。It is a shape figure of the reflection part of the half mirror of 8th Embodiment of this invention. 本発明の第９実施形態の光源装置を示す断面図である。It is sectional drawing which shows the light source device of 9th Embodiment of this invention. 本発明の第１０実施形態の光源装置を示す斜視図である。It is a perspective view which shows the light source device of 10th Embodiment of this invention. 本発明の第１１実施形態の光源装置を示す斜視図である。It is a perspective view which shows the light source device of 11th Embodiment of this invention. 本発明の第１１実施形態の光源装置を示す断面図である。It is sectional drawing which shows the light source device of 11th Embodiment of this invention. ハーフミラーが無い場合の輝度－角度プロファイル図である。It is a brightness-angle profile diagram when there is no half mirror. 第１１実施形態の輝度－角度プロファイル図である。It is a luminance-angle profile figure of 11th Embodiment. ハーフミラーがない場合と第４実施形態とを比較するグラフである。It is a graph which compares the case where there is no half mirror, and 4th Embodiment. ハーフミラーが無い場合の輝度－空間プロファイル図である。It is a brightness | luminance-space profile figure when there is no half mirror. 第１１実施形態の輝度－空間プロファイル図である。It is a brightness | luminance-space profile figure of 11th Embodiment. ハーフミラーがない場合と第１１実施形態とを比較するグラフである。It is a graph which compares the case where there is no half mirror with 11th Embodiment. 本発明の第１２実施形態の光源装置を示す断面図である。It is sectional drawing which shows the light source device of 12th Embodiment of this invention. 本発明の第１３実施形態の光源装置を示す斜視図である。It is a perspective view which shows the light source device of 13th Embodiment of this invention. 第１３実施形態の光源装置を示す断面図である。It is sectional drawing which shows the light source device of 13th Embodiment. 第１３実施形態の光源装置を示す断面図である。It is sectional drawing which shows the light source device of 13th Embodiment. 本発明の第１４実施形態の光源装置を示す斜視図である。It is a perspective view which shows the light source device of 14th Embodiment of this invention. 本発明の第１４実施形態の光源装置を示す上面図である。It is a top view which shows the light source device of 14th Embodiment of this invention. 本発明の第１５実施形態の光源装置を示す断面図である。It is sectional drawing which shows the light source device of 15th Embodiment of this invention. 本発明の第１６実施形態の光源装置を示す断面図である。It is sectional drawing which shows the light source device of 16th Embodiment of this invention. 本発明の第１７実施形態の面光源装置を示す斜視図である。It is a perspective view which shows the surface light source device of 17th Embodiment of this invention. 本発明の第１７実施形態の面光源装置を示す断面図である。It is sectional drawing which shows the surface light source device of 17th Embodiment of this invention. 本発明の第１８実施形態の表示装置の光源部を示す斜視図である。It is a perspective view which shows the light source part of the display apparatus of 18th Embodiment of this invention. 本発明の第１８実施形態の表示装置を示す断面図である。It is sectional drawing which shows the display apparatus of 18th Embodiment of this invention. 本発明の第１９実施形態の液晶表示装置を示す断面図である。It is sectional drawing which shows the liquid crystal display device of 19th Embodiment of this invention. 本発明の第１９実施形態の表示装置を示す断面図である。It is sectional drawing which shows the display apparatus of 19th Embodiment of this invention. 本発明の第２０実施形態の液晶表示装置を示す断面図である。It is sectional drawing which shows the liquid crystal display device of 20th Embodiment of this invention. 本発明の第２０実施形態の表示装置を示す断面図である。It is sectional drawing which shows the display apparatus of 20th Embodiment of this invention. 本発明の表示装置の一構成例である液晶表示装置の概略構成を示す正面図である。It is a front view which shows schematic structure of the liquid crystal display device which is one structural example of the display apparatus of this invention. 本発明の照明装置の概略構成を示す図である。It is a figure which shows schematic structure of the illuminating device of this invention. 本発明の照明装置の概略構成を示す図である。It is a figure which shows schematic structure of the illuminating device of this invention.
［第１実施形態］
　以下、本発明の第１実施形態について、図１～図５を用いて説明する。
　本実施形態では、例えば液晶表示装置のバックライトとして用いて好適な面光源装置の一例を示す。
　図１は、本実施形態の面光源装置を示す斜視図である。図２は、図１のＡ－Ａ’線に沿う断面図である。図３は、本実施形態の面光源装置における一つの光源を示す斜視図である。図４Ａは図３のＢ－Ｂ’線に沿う断面図、図４Ｂは図３のＣ－Ｃ’線に沿う断面図である。図５は、本実施形態の面光源装置における複数個の光源を示す正面図である。
　なお、以下の各図面においては各構成要素を見やすくするため、構成要素によって寸法の縮尺を異ならせて示すことがある。 [First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, an example of a surface light source device suitable for use as, for example, a backlight of a liquid crystal display device is shown.
FIG. 1 is a perspective view showing the surface light source device of this embodiment. FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. FIG. 3 is a perspective view showing one light source in the surface light source device of the present embodiment. 4A is a cross-sectional view taken along the line BB ′ of FIG. 3, and FIG. 4B is a cross-sectional view taken along the line CC ′ of FIG. FIG. 5 is a front view showing a plurality of light sources in the surface light source device of the present embodiment.
In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.
　本実施形態の面光源装置１１は、図１および図２に示すように、光源部１２と、導光体１３と、プリズムシート１４（方向変更用部材、方向変更部材）と、から構成されている。導光体１３は、光源部１２から射出された光を端面から入射させ、内部で伝播させる間に主面から射出させる機能を有する。プリズムシート１４は、導光体１３の主面から射出された光の進行方向を、主面の法線により近い方向に変更する機能を有する。なお、光源部１２の詳細な構成は後述する。 The surface light source device 11 of this embodiment is comprised from the light source part 12, the light guide 13, and the prism sheet 14 (direction changing member, direction changing member), as shown in FIG. 1 and FIG. Yes. The light guide 13 has a function of causing light emitted from the light source unit 12 to enter from the end face and to be emitted from the main surface while propagating inside. The prism sheet 14 has a function of changing the traveling direction of the light emitted from the main surface of the light guide 13 to a direction closer to the normal line of the main surface. The detailed configuration of the light source unit 12 will be described later.
　導光体１３は、例えばアクリル樹脂等の光透過性を有する樹脂からなる板体である。導光体１３は、光源部１２が設けられた端面１３ａに近い側から遠い側に向けて厚みが徐々に薄くなる楔形の形状を有している。すなわち、図２に示すように、後述する第１主面１３ｂに垂直な面（ｘｚ平面）で切断したときの導光体１３の断面形状は直角三角形である。導光体１３の端面１３ａは、光源部１２から射出された光を入射させる光入射面である。導光体１３の第１主面１３ｂ（図２における上側の面）は、内部に入射した光を射出させる光射出面である。 The light guide 13 is a plate made of a resin having optical transparency such as acrylic resin. The light guide 13 has a wedge shape in which the thickness gradually decreases from the side closer to the end surface 13 a where the light source unit 12 is provided to the side farther from the side. That is, as shown in FIG. 2, the cross-sectional shape of the light guide 13 when cut along a plane (xz plane) perpendicular to the first main surface 13b described later is a right triangle. The end surface 13 a of the light guide 13 is a light incident surface on which light emitted from the light source unit 12 is incident. The first main surface 13b (upper surface in FIG. 2) of the light guide 13 is a light emitting surface for emitting light incident on the inside.
　なお、本実施形態において、導光体１３の第１主面１３ｂの面内における光の伝播方向をｘ軸方向、光の伝播方向と直交する方向をｙ軸方向、第１主面と直交する方向（導光体１３の厚み方向）をｚ軸方向、と定義する。したがって、本明細書における「光の伝播方向」とは、図２に示す導光体１３のｘｚ断面内で光（１点鎖線の矢印Ｌで示す）が反射しつつ伝播する方向を意味するのではなく、導光体１３の第１主面１３ｂの法線方向から見て光が伝播する方向（実線の矢印Ｘで示す）を意味する。 In the present embodiment, the light propagation direction within the first main surface 13b of the light guide 13 is the x-axis direction, the direction orthogonal to the light propagation direction is the y-axis direction, and the first main surface is orthogonal. The direction (thickness direction of the light guide 13) is defined as the z-axis direction. Therefore, “the propagation direction of light” in this specification means the direction in which light (indicated by a dashed-dotted arrow L) propagates while reflecting in the xz section of the light guide 13 shown in FIG. Instead, it means a direction (indicated by a solid arrow X) in which light propagates when viewed from the normal direction of the first main surface 13b of the light guide 13.
　導光体１３の第１主面１３ｂに対向する第２主面１３ｃ（図２における下側の面）は、光の伝播方向において第１主面１３ｂに対して一定の傾斜角をもって傾斜している。第１主面１３ｂに対する第２主面１３ｃの傾斜角θ１（第１主面１３ｂと第２主面１３ｃとのなす角度、導光体１３の先端角と呼ぶ場合もある）は、例えば２°程度に設定される。第２主面１３ｃには、例えばアルミニウム等の光反射率の高い金属膜からなる反射ミラー１５が設けられている。反射ミラー１５が設けられたことで、第２主面１３ｃは、その全体が導光体１３の内部を伝播する光を反射させる反射面として機能する。なお、反射ミラー１５は、導光体１３の第２主面１３ｃに直接形成された金属膜で構成しても良いし、導光体１３とは別体に作製した反射板を貼り合わせた構成としても良い。 The second main surface 13c (the lower surface in FIG. 2) facing the first main surface 13b of the light guide 13 is inclined with a certain inclination angle with respect to the first main surface 13b in the light propagation direction. Yes. The inclination angle θ1 of the second main surface 13c with respect to the first main surface 13b (the angle between the first main surface 13b and the second main surface 13c, sometimes referred to as the tip angle of the light guide 13) is, for example, 2 °. Set to degree. The second main surface 13c is provided with a reflection mirror 15 made of a metal film having a high light reflectance such as aluminum. By providing the reflection mirror 15, the second main surface 13 c functions as a reflection surface that reflects the light propagating through the light guide 13 as a whole. The reflection mirror 15 may be formed of a metal film directly formed on the second main surface 13c of the light guide 13, or a structure in which a reflection plate manufactured separately from the light guide 13 is bonded. It is also good.
　光源部１２は、図１および図５に示すように、複数の光源１６が、光の伝播方向Ｘと直交する方向（ｙ軸方向）に１列に配列された構成を有している。光源１６は、図３および図４Ａ、図４Ｂに示すように、ＬＥＤ１７（発光素子）と、シリンドリカルレンズ１８（凸レンズ）と、凹面ミラー１９と、を備えている。シリンドリカルレンズ１８は、例えばアクリル樹脂等の樹脂で構成されている。シリンドリカルレンズ１８は、一方が凸面、他方が平坦面となったレンズ、いわゆる平凸レンズである。光は平坦面１８ａから射出されるため、以降、この平坦面１８ａを光射出面と称する。一方、凸面は、なだらかに湾曲した湾曲面１８ｂと、湾曲面１８ｂの両端に連続する２つの平坦な側面１８ｃと、を有している。 1 and 5, the light source unit 12 has a configuration in which a plurality of light sources 16 are arranged in a line in a direction (y-axis direction) orthogonal to the light propagation direction X. As shown in FIGS. 3, 4 </ b> A, and 4 </ b> B, the light source 16 includes an LED 17 (light emitting element), a cylindrical lens 18 (convex lens), and a concave mirror 19. The cylindrical lens 18 is made of a resin such as an acrylic resin. The cylindrical lens 18 is a so-called plano-convex lens in which one is a convex surface and the other is a flat surface. Since light is emitted from the flat surface 18a, the flat surface 18a is hereinafter referred to as a light emission surface. On the other hand, the convex surface has a curved surface 18b that is gently curved, and two flat side surfaces 18c that are continuous to both ends of the curved surface 18b.
　シリンドリカルレンズ１８をｘｙ平面で切断した断面形状を見ると、図４Ａに示すように、凸面のうち、湾曲面１８ｂは焦点Ｐを有する曲線形状を有している。本実施形態の場合、具体的には、湾曲面１８ｂの断面形状は放物線状である。一方、シリンドリカルレンズ１８をｘｚ平面で切断した断面形状を見ると、図４Ｂに示すように、湾曲面１８ｂは直線形状である。すなわち、シリンドリカルレンズ１８の湾曲面１８ｂは、ｘｙ平面内において湾曲し、ｘｙ平面内においては湾曲していない放物面である。 Looking at the cross-sectional shape of the cylindrical lens 18 cut along the xy plane, the curved surface 18b of the convex surface has a curved shape having a focal point P as shown in FIG. 4A. In the case of this embodiment, specifically, the cross-sectional shape of the curved surface 18b is a parabolic shape. On the other hand, when the cross-sectional shape obtained by cutting the cylindrical lens 18 along the xz plane is viewed, the curved surface 18b is linear as shown in FIG. 4B. That is, the curved surface 18b of the cylindrical lens 18 is a paraboloid that is curved in the xy plane and not curved in the xy plane.
　シリンドリカルレンズ１８の湾曲面１８ｂに沿って凹面ミラー１９が設けられている。凹面ミラー１９は、シリンドリカルレンズ１８の湾曲面１８ｂに直接形成されたアルミニウム等の光反射率の高い金属膜で構成されている。このように、シリンドリカルレンズ１８の湾曲面１８ｂと凹面ミラー１９とが密着しているため、凹面ミラー１９の形状は湾曲面１８ｂの形状が反映された放物面となる。したがって、凹面ミラー１９の焦点の位置はシリンドリカルレンズ１８の焦点の位置と一致する。焦点を図４Ａに点Ｐで示す。なお、シリンドリカルレンズ１８の湾曲面１８ｂに凹面ミラー１９を直接形成する構成に代えて、シリンドリカルレンズとは別体に作製した凹面ミラーを貼り合わせた構成としても良い。 A concave mirror 19 is provided along the curved surface 18 b of the cylindrical lens 18. The concave mirror 19 is made of a metal film having a high light reflectance such as aluminum directly formed on the curved surface 18 b of the cylindrical lens 18. Thus, since the curved surface 18b of the cylindrical lens 18 and the concave mirror 19 are in close contact, the shape of the concave mirror 19 becomes a paraboloid reflecting the shape of the curved surface 18b. Therefore, the focal position of the concave mirror 19 coincides with the focal position of the cylindrical lens 18. The focal point is indicated by point P in FIG. Instead of directly forming the concave mirror 19 on the curved surface 18b of the cylindrical lens 18, a configuration may be adopted in which a concave mirror manufactured separately from the cylindrical lens is bonded.
　図４Ａに示すように、シリンドリカルレンズ１８の光射出面１８ａには、ＬＥＤ１７を内部に挿入できるだけの深さを有する溝１１０が設けられている。シリンドリカルレンズ１８をｘｙ平面で切断したときの溝１１０の底部の断面形状は円弧状に丸められている。溝１１０の内部には、棒状のＬＥＤ１７が配置されている。ＬＥＤ１７は、発光面１７ａを凹面ミラー１９に向けた姿勢で配置されている。また、ＬＥＤ１７と凹面ミラー１９およびシリンドリカルレンズ１８とは、凹面ミラー１９およびシリンドリカルレンズ１８の焦点Ｐが発光面１７ａ上に位置するように、互いの位置関係や寸法、形状等が設定されている。 As shown in FIG. 4A, the light exit surface 18a of the cylindrical lens 18 is provided with a groove 110 having a depth sufficient to insert the LED 17 therein. The cross-sectional shape of the bottom of the groove 110 when the cylindrical lens 18 is cut along the xy plane is rounded into an arc. Inside the groove 110, a rod-shaped LED 17 is arranged. The LED 17 is arranged in a posture in which the light emitting surface 17 a faces the concave mirror 19. Further, the LED 17, the concave mirror 19 and the cylindrical lens 18 are set such that their positional relationship, size, shape and the like are set so that the focal point P of the concave mirror 19 and the cylindrical lens 18 is located on the light emitting surface 17a.
　ＬＥＤ１７の発光面１７ａが凹面ミラー１９を向いていることにより、ＬＥＤ１７の発光面１７ａから射出された光の略全てが凹面ミラー１９に向かい、凹面ミラー１９で反射した後、シリンドリカルレンズ１８の光射出面１８ａから射出される。したがって、ＬＥＤ１７の発光面１７ａから射出された光のうち、凹面ミラー１９で反射することなく、直接射出される光はほとんど存在しない。ＬＥＤ１７は、特に指向性を有するものではなく、所定の拡散角で光を射出する一般的なＬＥＤを用いることができる。シリンドリカルレンズ１８の凸面のうち、最大の拡散角でＬＥＤ１７から射出された光が到達する位置までは少なくとも放物面となっており、凹面ミラー１９が存在している。よって、ＬＥＤ１７からの光が到達しない部分は平坦な側面１８ｃとなっており、凹面ミラー１９が存在しない。シリンドリカルレンズ１８の側面１８ｃは、隣接するシリンドリカルレンズ１８の側面１８ｃと互いに接触する接触面となる。 Since the light emitting surface 17a of the LED 17 faces the concave mirror 19, almost all of the light emitted from the light emitting surface 17a of the LED 17 is directed to the concave mirror 19, reflected by the concave mirror 19, and then emitted from the cylindrical lens 18. Ejected from the surface 18a. Therefore, of the light emitted from the light emitting surface 17a of the LED 17, there is almost no light emitted directly without being reflected by the concave mirror 19. The LED 17 is not particularly directional, and a general LED that emits light at a predetermined diffusion angle can be used. Of the convex surface of the cylindrical lens 18, at least a parabolic surface reaches a position where the light emitted from the LED 17 reaches the maximum diffusion angle, and the concave mirror 19 exists. Therefore, the portion where the light from the LED 17 does not reach is a flat side surface 18c, and the concave mirror 19 does not exist. The side surface 18c of the cylindrical lens 18 is a contact surface that contacts the side surface 18c of the adjacent cylindrical lens 18.
　本実施形態においては、図５に示すように、各シリンドリカルレンズ１８の光射出面１８ａにおいて上端から下端までを貫通するように溝１１０が設けられている。ＬＥＤ１７は、シリンドリカルレンズ１８の上端から下端まで達するように、溝１１０の全体にわたって設けられている。ＬＥＤ１７に電流を供給するための配線（図示略）は、シリンドリカルレンズ１８の上端および下端から引き出されている。ＬＥＤ１７と溝１１０との間には僅かな間隙１１１Ａが設けられている。この間隙１１１Ａには、光学接着剤等が充填されても良いし、何も充填されずに空気が存在していても良い。なお、本実施形態では、複数の別体のシリンドリカルレンズ１８を連結した構成としたが、これら複数のシリンドリカルレンズを一体にした構成のレンチキュラーレンズを用いても良い。 In this embodiment, as shown in FIG. 5, a groove 110 is provided so as to penetrate from the upper end to the lower end on the light exit surface 18 a of each cylindrical lens 18. The LED 17 is provided over the entire groove 110 so as to reach from the upper end to the lower end of the cylindrical lens 18. Wiring (not shown) for supplying current to the LED 17 is drawn from the upper end and the lower end of the cylindrical lens 18. A slight gap 111 </ b> A is provided between the LED 17 and the groove 110. The gap 111A may be filled with an optical adhesive or the like, or air may be present without filling anything. In the present embodiment, a plurality of separate cylindrical lenses 18 are connected, but a lenticular lens having a structure in which these plurality of cylindrical lenses are integrated may be used.
　図１および図２に示すように、プリズムシート１４が、導光体１３の第１主面（光射出面）１３ｂに対向する位置（図２における導光体１３の上方）に設けられている。プリズムシート１４は、光の伝播方向Ｘと直交する方向に延在する複数のプリズム構造体１１１が一面に設けられたものである。プリズムシート１４は、複数のプリズム構造体１１１が設けられた面が導光体１３の光射出面１３ｂに対向するように配置されている。ｘｚ平面で切断した断面における一つのプリズム構造体１１１の断面形状は三角形状である。プリズム構造体１１１は、導光体１３の光射出面１３ｂに対して直交する第１面１１１ａと、第１面１１１ａに対して所定の先端角θ２をなす第２面１１１ｂと、を有している。 As shown in FIGS. 1 and 2, the prism sheet 14 is provided at a position (above the light guide 13 in FIG. 2) facing the first main surface (light emission surface) 13 b of the light guide 13. . The prism sheet 14 is provided with a plurality of prism structures 111 extending in a direction orthogonal to the light propagation direction X on one surface. The prism sheet 14 is disposed so that the surface on which the plurality of prism structures 111 are provided faces the light exit surface 13 b of the light guide 13. The cross-sectional shape of one prism structure 111 in a cross section cut along the xz plane is a triangular shape. The prism structure 111 includes a first surface 111a that is orthogonal to the light exit surface 13b of the light guide 13, and a second surface 111b that forms a predetermined tip angle θ2 with respect to the first surface 111a. Yes.
　以下、上記構成の面光源装置１１の作用について説明する。
　ＬＥＤ１７の発光面１７ａは所定の面積を有しているため、発光面１７ａ上の全ての点が凹面ミラー１９およびシリンドリカルレンズ１８の焦点Ｐの位置に必ずしも一致するわけではない。ただし、以下では説明を簡単にするため、発光面１７ａの面積が十分に小さく、発光面１７ａが焦点Ｐと一致しているものとして説明する。 Hereinafter, the operation of the surface light source device 11 configured as described above will be described.
Since the light emitting surface 17a of the LED 17 has a predetermined area, not all points on the light emitting surface 17a necessarily coincide with the positions of the focal point P of the concave mirror 19 and the cylindrical lens 18. However, for the sake of simplicity, the following description will be made assuming that the area of the light emitting surface 17a is sufficiently small and the light emitting surface 17a is coincident with the focal point P.
　ＬＥＤ１７の発光面１７ａから発せられた光Ｌは、所定の拡散角をもって凹面ミラー１９に向かい、凹面ミラー１９で反射する。ここで、導光体１３の光射出面１３ｂに平行な平面（ｘｙ平面）内での光の振る舞いを考える。図４Ａに示すように、発光面１７ａの位置が焦点Ｐと一致しているため、ＬＥＤ１７から発せられた光Ｌは、凹面ミラー１９に対してどのような角度で入射したとしても、凹面ミラー１９で反射した後は凹面ミラー１９の光軸に平行な方向に進行する。したがって、ＬＥＤ１７の発光面１７ａから発せられた直後の拡散光は、凹面ミラー１９で反射することで平行化された光、すなわち高い指向性を持つ光に変換され、シリンドリカルレンズ１８の光射出面１８ａから射出される。 The light L emitted from the light emitting surface 17a of the LED 17 is directed to the concave mirror 19 with a predetermined diffusion angle and reflected by the concave mirror 19. Here, the behavior of light in a plane (xy plane) parallel to the light exit surface 13b of the light guide 13 is considered. As shown in FIG. 4A, since the position of the light emitting surface 17a coincides with the focal point P, the light L emitted from the LED 17 can be incident on the concave mirror 19 at any angle. Then, the light travels in a direction parallel to the optical axis of the concave mirror 19. Therefore, the diffused light immediately after being emitted from the light emitting surface 17a of the LED 17 is converted into parallel light by being reflected by the concave mirror 19, that is, light having high directivity, and the light emitting surface 18a of the cylindrical lens 18 is converted. Is injected from.
　次に、光の伝播方向Ｘに平行、かつ導光体１３の光射出面１３ｂに垂直な平面（ｘｚ平面）内での光の振る舞いを考える。図４Ｂに示すように、ｘｚ平面内で見る限りにおいては、凹面ミラー１９は曲率を有していないので、凹面ミラー１９は平面ミラーのように機能する。すなわち、光Ｌは、凹面ミラー１９において入射角に等しい反射角で反射する。よって、光Ｌは、ＬＥＤ１７の発光面１７ａから発せられた直後の拡散角を維持したまま、シリンドリカルレンズ１８の光射出面１８ａから射出される。 Next, consider the behavior of light in a plane (xz plane) parallel to the light propagation direction X and perpendicular to the light exit surface 13 b of the light guide 13. As shown in FIG. 4B, as long as viewed in the xz plane, since the concave mirror 19 has no curvature, the concave mirror 19 functions like a plane mirror. That is, the light L is reflected by the concave mirror 19 at a reflection angle equal to the incident angle. Therefore, the light L is emitted from the light emitting surface 18a of the cylindrical lens 18 while maintaining the diffusion angle immediately after being emitted from the light emitting surface 17a of the LED 17.
　以上をまとめると、シリンドリカルレンズ１８の光射出面１８ａから射出された時点において、光Ｌは、導光体１３の光射出面１３ｂに平行な平面（ｘｙ平面）内でのみ高い指向性を持ち、光の伝播方向Ｘに平行、かつ導光体１３の光射出面１３ｂに垂直な平面（ｘｚ平面）内では指向性を持たない状態となる。このような光Ｌが、光入射面（端面）１３ａから導光体１３に入射される。 In summary, when the light L is emitted from the light exit surface 18a of the cylindrical lens 18, the light L has high directivity only in a plane (xy plane) parallel to the light exit surface 13b of the light guide 13. In a plane (xz plane) parallel to the light propagation direction X and perpendicular to the light exit surface 13b of the light guide 13, there is no directivity. Such light L is incident on the light guide 13 from the light incident surface (end surface) 13a.
　次に、光入射面（端面）１３ａから導光体１３に入射された光Ｌは、図２に示すように、第１主面１３ｂ（光射出面）と第２主面１３ｃ（反射面）との間で反射を繰り返しつつ、導光体１３の内部を光の伝播方向Ｘ（図２の右側）に向けて進行する。仮に第１主面と第２主面とが平行であったとすると、光が反射を繰り返しても、第１主面および第２主面への光の入射角は変化しない。ところが、本実施形態の場合、導光体１３は光入射面１３ａ側から離れるにつれて厚みが徐々に薄くなる楔形であり、第１主面１３ｂに対して第２主面１３ｃが所定の傾斜角を有している。そのため、光Ｌは、第１主面１３ｂおよび第２主面１３ｃで反射する毎に第１主面１３ｂおよび第２主面１３ｃへの入射角が小さくなる。 Next, the light L incident on the light guide 13 from the light incident surface (end surface) 13a is, as shown in FIG. 2, a first main surface 13b (light emission surface) and a second main surface 13c (reflection surface). The light guide 13 travels in the light propagation direction X (right side in FIG. 2) while repeating the reflection. Assuming that the first main surface and the second main surface are parallel, the incident angle of light on the first main surface and the second main surface does not change even if light is repeatedly reflected. However, in the case of the present embodiment, the light guide 13 has a wedge shape in which the thickness gradually decreases with increasing distance from the light incident surface 13a side, and the second main surface 13c has a predetermined inclination angle with respect to the first main surface 13b. Have. Therefore, each time the light L is reflected by the first main surface 13b and the second main surface 13c, the incident angle on the first main surface 13b and the second main surface 13c becomes small.
　ここで、例えば導光体１３を構成するアクリル樹脂の屈折率が１．５、空気の屈折率を１．０とすると、導光体１３の第１主面１３ｂ（光射出面）における臨界角、すなわち導光体１３を構成するアクリル樹脂と空気との界面における臨界角は、スネルの法則から４２°程度となる。導光体１３に入射した直後の光が第１主面１３ｂに入射した際、第１主面１３ｂへの光Ｌの入射角が臨界角である４２°よりも大きい間は全反射条件を満たすため、光Ｌは第１主面１３ｂで全反射する。その後、光Ｌが第１主面１３ｂと第２主面１３ｃとの間で反射を繰り返し、第１主面１３ｂへの光Ｌの入射角が臨界角である４２°よりも小さくなった時点で全反射条件を満たさなくなり、光Ｌは外部空間に射出される。 Here, for example, when the refractive index of the acrylic resin constituting the light guide 13 is 1.5 and the refractive index of air is 1.0, the critical angle on the first main surface 13b (light emission surface) of the light guide 13 is shown. That is, the critical angle at the interface between the acrylic resin constituting the light guide 13 and the air is about 42 ° from Snell's law. When light immediately after entering the light guide 13 enters the first main surface 13b, the total reflection condition is satisfied as long as the incident angle of the light L on the first main surface 13b is larger than 42 ° which is a critical angle. Therefore, the light L is totally reflected by the first main surface 13b. Thereafter, when the light L repeatedly reflects between the first main surface 13b and the second main surface 13c, the incident angle of the light L on the first main surface 13b becomes smaller than 42 ° which is a critical angle. The light L is emitted to the external space because the total reflection condition is not satisfied.
　すなわち、光Ｌは、第１主面１３ｂへの入射角が臨界角よりも大きい間は導光体１３の内部に閉じ込められ、第１主面１３ｂへの入射角が臨界角よりも小さくなった時点で第１主面１３ｂから順次射出される。光Ｌは第１主面１３ｂから射出される際に屈折するので、第１主面１３ｂへの入射角が４２°程度の光は、射出角が７０°程度の光となって射出される。このように、光の伝播方向Ｘに平行、かつ導光体１３の光射出面１３ｂに垂直な平面（ｘｚ平面）内で見たとき、光Ｌは導光体１３に入射した時点では指向性を持たないが、導光体１３から射出する時点では高い指向性を有することになる。 That is, the light L is confined inside the light guide 13 while the incident angle on the first main surface 13b is larger than the critical angle, and the incident angle on the first main surface 13b becomes smaller than the critical angle. At the time, the first main surface 13b is sequentially ejected. Since the light L is refracted when emitted from the first main surface 13b, light having an incident angle of about 42 ° to the first main surface 13b is emitted as light having an emission angle of about 70 °. Thus, when viewed in a plane (xz plane) parallel to the light propagation direction X and perpendicular to the light exit surface 13 b of the light guide 13, the light L is directional at the point of incidence on the light guide 13. However, at the time of emission from the light guide 13, it has high directivity.
　導光体１３から射出するときの光Ｌの射出角は７０°程度であり、光Ｌはかなり水平に近い方向に射出される。したがって、プリズムシート１４を用いて、導光体１３から射出された光Ｌを導光体１３の第１主面１３ｂの法線方向に近い方向に立ち上げる必要がある。具体的には、先端角θ２が３８．５°程度のプリズム構造体１１１を有するプリズムシート１４を用い、光Ｌを、プリズム構造体１１１の第１面１１１ａから入射させ、第２面１１１ｂで反射させることで、導光体１３の第１主面１３ｂに対して略法線方向に立ち上げることができる。 The emission angle of the light L when emitted from the light guide 13 is about 70 °, and the light L is emitted in a substantially horizontal direction. Therefore, it is necessary to use the prism sheet 14 to raise the light L emitted from the light guide 13 in a direction close to the normal direction of the first main surface 13 b of the light guide 13. Specifically, a prism sheet 14 having a prism structure 111 with a tip angle θ2 of about 38.5 ° is used, and light L is incident from the first surface 111a of the prism structure 111 and reflected by the second surface 111b. By doing so, the light guide 13 can be raised in a substantially normal direction with respect to the first main surface 13b.
　本実施形態の面光源装置１１においては、ＬＥＤ１７から発せられた光を光源１６の凹面ミラー１９で反射させることで、導光体１３の光射出面１３ｂに平行な平面（ｘｙ平面）内で高い指向性を持たせた後、導光体１３を透過させることで、光の伝播方向Ｘに平行、かつ導光体１３の光射出面１３ｂに垂直な平面（ｘｚ平面）内でも高い指向性を持たせることができる。さらに、高い指向性を持つ光を、プリズムシート１４を透過させることで、導光体１３の第１主面１３ｂの法線方向に取り出すことができる。その結果、全ての方位角において高い指向性を持つ光を得ることができる。 In the surface light source device 11 of the present embodiment, the light emitted from the LED 17 is reflected by the concave mirror 19 of the light source 16, so that it is high in a plane (xy plane) parallel to the light exit surface 13 b of the light guide 13. After imparting directivity, by transmitting the light guide 13, high directivity can be achieved even in a plane (xz plane) parallel to the light propagation direction X and perpendicular to the light exit surface 13b of the light guide 13. You can have it. Furthermore, light having high directivity can be extracted in the normal direction of the first main surface 13 b of the light guide 13 by transmitting the light through the prism sheet 14. As a result, light having high directivity at all azimuth angles can be obtained.
　本発明者らは、本実施形態の面光源装置を前提として、導光体から射出される光の輝度－角度プロファイルに関する光学シミュレーションを行った。シミュレーション条件として、凹面ミラーの曲率半径を２．５ｍｍ、シリンドリカルレンズの幅（ｙ軸方向の寸法）を５ｍｍ、ＬＥＤの幅（ｙ軸方向の寸法）を０．４ｍｍ、導光体の先端角を２°に設定した。シミュレーションを行った結果、本実施形態の面光源装置では、導光体の第１主面の法線方向を中心とした全ての方位角において、半値全幅が１５°以下という高い指向性を有する光を得られることが確認された。 The present inventors performed an optical simulation on the luminance-angle profile of light emitted from the light guide on the premise of the surface light source device of the present embodiment. As simulation conditions, the radius of curvature of the concave mirror is 2.5 mm, the width of the cylindrical lens (dimension in the y-axis direction) is 5 mm, the width of the LED (dimension in the y-axis direction) is 0.4 mm, and the tip angle of the light guide is Set to 2 °. As a result of the simulation, in the surface light source device of this embodiment, light having a high directivity with a full width at half maximum of 15 ° or less at all azimuth angles centered on the normal direction of the first main surface of the light guide. It was confirmed that
　また、本実施形態の光源部１２においては、シリンドリカルレンズ１８の湾曲面１８ｂ上に凹面ミラー１９が直接形成され、シリンドリカルレンズ１８に設けられた溝１１０の内部にＬＥＤ１７が装入されているため、部品点数が少なく、導光体１３の大きさに対して比較的小型の光源部１２を作製することができる。また、光源部１２が光の伝播方向Ｘと直交する方向に配列された複数の光源１６を有しているため、輝度が高く、幅が広い導光体１３に対応した面光源装置１１を構成することができる。 Further, in the light source unit 12 of the present embodiment, the concave mirror 19 is formed directly on the curved surface 18b of the cylindrical lens 18, and the LED 17 is inserted into the groove 110 provided in the cylindrical lens 18. The number of parts is small, and the light source unit 12 that is relatively small with respect to the size of the light guide 13 can be manufactured. Further, since the light source unit 12 includes a plurality of light sources 16 arranged in a direction orthogonal to the light propagation direction X, the surface light source device 11 corresponding to the light guide 13 having a high luminance and a wide width is configured. can do.
　また、仮にシリンドリカルレンズに設けた溝の底部が角部を有していたとすると、その角部は互いに直交する２つの平面（第１の平面、第２の平面）で構成される。このとき、ＬＥＤから射出された光が第１の平面に入射する場合と第２の平面に入射する場合とで、光の屈折方向が急激に変化する。そのため、最終的に面光源装置から射出される光の角度－輝度特性が複数のピークを有するものとなる。その点、本実施形態の溝１１０の底部は円弧状に丸められているため、ＬＥＤ１７から射出された光の屈折方向が急激に変化することがない。その結果、なだらかな角度－輝度特性を有する光が得られる。 If the bottom of the groove provided in the cylindrical lens has a corner, the corner is composed of two planes (a first plane and a second plane) orthogonal to each other. At this time, the light refraction direction changes abruptly when light emitted from the LED is incident on the first plane and when incident on the second plane. Therefore, the angle-luminance characteristic of the light finally emitted from the surface light source device has a plurality of peaks. In that respect, since the bottom of the groove 110 of the present embodiment is rounded in an arc shape, the refraction direction of the light emitted from the LED 17 does not change abruptly. As a result, light having a gentle angle-luminance characteristic can be obtained.
［第２実施形態］
　以下、本発明の第２実施形態について、図６を用いて説明する。
　本実施形態の面光源装置の基本構成は第１実施形態と同様であり、導光体の構成が第１実施形態と異なる。
　図６は、本実施形態の面光源装置をｘｚ平面で切断した断面図であり、第１実施形態の図２に相当する図である。図６において図２と共通の構成要素には同一の符号を付し、説明を省略する。 [Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the surface light source device of this embodiment is the same as that of the first embodiment, and the configuration of the light guide is different from that of the first embodiment.
FIG. 6 is a cross-sectional view of the surface light source device of the present embodiment cut along the xz plane, and corresponds to FIG. 2 of the first embodiment. In FIG. 6, the same components as those in FIG.
　本実施形態の面光源装置１１４は、図６に示すように、光源部１２と、導光体１１５と、プリズムシート１４と、を備えている。光源部１２とプリズムシート１４の構成は第１実施形態と同様である。導光体１１５は、光の伝播方向Ｘと直交する方向（ｙ軸方向）に延在する複数のプリズム構造体１１６が設けられたものである。導光体１１５は、複数のプリズム構造体１１６が設けられた面がプリズムシート１４と反対側を向くように配置されている。 The surface light source device 114 of this embodiment includes a light source unit 12, a light guide 115, and a prism sheet 14, as shown in FIG. The configurations of the light source unit 12 and the prism sheet 14 are the same as those in the first embodiment. The light guide 115 is provided with a plurality of prism structures 116 extending in a direction orthogonal to the light propagation direction X (y-axis direction). The light guide 115 is disposed so that the surface on which the plurality of prism structures 116 are provided faces the opposite side to the prism sheet 14.
　ｘｚ平面で切断した一つのプリズム構造体１１６の断面形状は三角形状である。プリズム構造体１１６は、導光体１１５の第１主面１１５ｂに対して直交する第１面１１６ａと、第１面１１６ａに対して所定の先端角θ３をなす第２面１１６ｂと、を有している。プリズム構造体１１６の第２面１１６ｂは、第１主面１１５ｂに平行な面に対する傾斜角θ４が全てのプリズム構造体１１６にわたって等しくなるように設定されている。一例として、各プリズム構造体１１６の先端角θ３は８８°に設定され、第２面１１６ｂの傾斜角θ４は２°に設定されている。本実施形態の場合、プリズム構造体１１６の第２面１１６ｂが内部を伝播する光Ｌを反射させる反射面として機能する。 The cross-sectional shape of one prism structure 116 cut along the xz plane is triangular. The prism structure 116 includes a first surface 116a that is orthogonal to the first main surface 115b of the light guide 115, and a second surface 116b that forms a predetermined tip angle θ3 with respect to the first surface 116a. ing. The second surface 116b of the prism structure 116 is set so that the inclination angle θ4 with respect to the surface parallel to the first main surface 115b is equal over all the prism structures 116. As an example, the tip angle θ3 of each prism structure 116 is set to 88 °, and the inclination angle θ4 of the second surface 116b is set to 2 °. In the case of the present embodiment, the second surface 116b of the prism structure 116 functions as a reflecting surface that reflects the light L propagating inside.
　導光体１１５の内部を伝播する光Ｌは、第１主面１１５ｂとプリズム構造体１６の第２面１１６ｂとの間で反射を繰り返し、第１主面１１５ｂへの光Ｌの入射角が臨界角よりも小さくなった時点で外部空間に取り出され、プリズムシート１４を経て上方に射出される。 The light L propagating through the light guide 115 is repeatedly reflected between the first main surface 115b and the second surface 116b of the prism structure 16, and the incident angle of the light L on the first main surface 115b is critical. When it becomes smaller than the corner, it is taken out to the external space and emitted upward through the prism sheet 14.
　本実施形態の面光源装置１１４においても、全ての方位角において高い指向性を持つ光が得られる、という第１実施形態と同様の効果を得ることができる。 Also in the surface light source device 114 of this embodiment, it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained in all azimuth angles.
［第３実施形態］
　以下、本発明の第３実施形態について、図７を用いて説明する。
　本実施形態の面光源装置の基本構成は第１実施形態と同様であり、光源の構成が第１実施形態と異なる。
　図７は、本実施形態の面光源装置における光源をｘｙ平面で切断した断面図であり、第１実施形態の図４Ａに相当する図である。図７において図４Ａと共通の構成要素には同一の符号を付し、説明を省略する。 [Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
The basic configuration of the surface light source device of this embodiment is the same as that of the first embodiment, and the configuration of the light source is different from that of the first embodiment.
FIG. 7 is a cross-sectional view of the light source in the surface light source device of the present embodiment cut along the xy plane, and corresponds to FIG. 4A of the first embodiment. In FIG. 7, the same components as those in FIG. 4A are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態の光源１１９は、図７に示すように、ＬＥＤ１７と、凹面ミラー１９と、シリンドリカルレンズ１２０と、を備えている。第１実施形態では、シリンドリカルレンズ１８の光射出面１８ａに溝１１０を設け、溝１１０の内部にＬＥＤ１７を挿入した。これに対して、本実施形態では、シリンドリカルレンズ１２０の光射出面１２０ａには溝を設けていない。ＬＥＤ１７は、シリンドリカルレンズ１２０の光射出面１２０ａ上に配置されている。ＬＥＤ１７は、光学接着剤等を用いてシリンドリカルレンズ１２０の光射出面１２０ａ上に固定されていても良いし、他の固定用部材を用いて固定されていても良い。ＬＥＤ１７は、その発光面１７ａ上に凹面ミラー１９およびシリンドリカルレンズ１２０の焦点Ｐが位置するように配置されている。 The light source 119 of the present embodiment includes an LED 17, a concave mirror 19, and a cylindrical lens 120 as shown in FIG. In the first embodiment, the groove 110 is provided on the light exit surface 18 a of the cylindrical lens 18, and the LED 17 is inserted into the groove 110. On the other hand, in this embodiment, no groove is provided on the light exit surface 120a of the cylindrical lens 120. The LED 17 is disposed on the light exit surface 120 a of the cylindrical lens 120. The LED 17 may be fixed on the light emission surface 120a of the cylindrical lens 120 using an optical adhesive or the like, or may be fixed using another fixing member. The LED 17 is disposed so that the focal point P of the concave mirror 19 and the cylindrical lens 120 is positioned on the light emitting surface 17a.
　本実施形態の面光源装置においても、全ての方位角において高い指向性を持つ光が得られる、という第１実施形態と同様の効果を得ることができる。本実施形態の場合、シリンドリカルレンズ１２０に溝を形成するための加工が不要であるため、光源部の製造が容易になる。 Also in the surface light source device of the present embodiment, it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles. In the case of this embodiment, since the process for forming a groove in the cylindrical lens 120 is not required, the light source unit can be easily manufactured.
［第４実施形態］
　以下、本発明の第４実施形態について、図８を用いて説明する。
　本実施形態の面光源装置の基本構成は第１実施形態と同様であり、光源の構成が第１実施形態と異なる。
　図８は、本実施形態の面光源装置における光源をｘｚ平面で切断した断面図であり、第１実施形態の図４Ｂに相当する図である。図８において図４Ｂと共通の構成要素には同一の符号を付し、説明を省略する。 [Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the surface light source device of this embodiment is the same as that of the first embodiment, and the configuration of the light source is different from that of the first embodiment.
FIG. 8 is a cross-sectional view of the light source in the surface light source device of the present embodiment cut along the xz plane, and corresponds to FIG. 4B of the first embodiment. In FIG. 8, the same components as those in FIG. 4B are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態の光源１２３は、図８に示すように、ＬＥＤ１２４と、凹面ミラー１９と、シリンドリカルレンズ１２５と、を備えている。第１実施形態では、シリンドリカルレンズ１８の上端から下端まで貫通するように溝１１０が設けられ、ＬＥＤ１７が溝１１０の全体にわたって配置されていた。これに対して、本実施形態では、シリンドリカルレンズ１２５に設けられた溝２６はシリンドリカルレンズ１２５の上端から下端まで貫通していない。溝２６はシリンドリカルレンズ１２５の高さ方向の一部に設けられ、溝２６の内部にＬＥＤ１２４が挿入されている。すなわち、ＬＥＤ１２４の長さ（ｚ軸方向の寸法）は、シリンドリカルレンズ１２５の高さ（ｚ軸方向の寸法）よりも短い。 The light source 123 of the present embodiment includes an LED 124, a concave mirror 19, and a cylindrical lens 125, as shown in FIG. In the first embodiment, the groove 110 is provided so as to penetrate from the upper end to the lower end of the cylindrical lens 18, and the LED 17 is disposed over the entire groove 110. In contrast, in the present embodiment, the groove 26 provided in the cylindrical lens 125 does not penetrate from the upper end to the lower end of the cylindrical lens 125. The groove 26 is provided in a part of the cylindrical lens 125 in the height direction, and the LED 124 is inserted into the groove 26. That is, the length (dimension in the z-axis direction) of the LED 124 is shorter than the height (dimension in the z-axis direction) of the cylindrical lens 125.
　本実施形態の面光源装置においても、全ての方位角において高い指向性を持つ光が得られる、という第１実施形態と同様の効果を得ることができる。本実施形態の場合、第１実施形態に比べてＬＥＤ１２４の長さが短く済むため、面光源装置のコストを削減することができる。 Also in the surface light source device of the present embodiment, it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles. In the case of this embodiment, since the length of the LED 124 is shorter than that of the first embodiment, the cost of the surface light source device can be reduced.
［第５実施形態］
　以下、本発明の第５実施形態について、図９Ａ、および図９Ｂを用いて説明する。
　本実施形態の面光源装置の基本構成は第１実施形態と同様であり、光源の構成が第１実施形態と異なる。
　図９Ａは、本実施形態の面光源装置における光源を示す斜視図であり、第１実施形態の図３に相当する図である。図９Ｂは、本実施形態の光源をｘｙ平面で切断したときの断面図であり、第１実施形態の図４Ａに相当する図である。図９Ａ、図９Ｂにおいて図３、図４Ａと共通の構成要素には同一の符号を付し、説明を省略する。 [Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIGS. 9A and 9B.
The basic configuration of the surface light source device of this embodiment is the same as that of the first embodiment, and the configuration of the light source is different from that of the first embodiment.
FIG. 9A is a perspective view showing a light source in the surface light source device of this embodiment, and corresponds to FIG. 3 of the first embodiment. FIG. 9B is a cross-sectional view when the light source of the present embodiment is cut along the xy plane, and corresponds to FIG. 4A of the first embodiment. 9A and 9B, the same components as those in FIGS. 3 and 4A are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態の光源１２９は、図９Ａ、図９Ｂに示すように、ＬＥＤ１７と、凹面ミラー１３０と、を備えており、シリンドリカルレンズを備えていない。すなわち、第１実施形態においてＬＥＤ１７と凹面ミラー１９との間のシリンドリカルレンズ１８が存在していた領域には、本実施形態では空気層が存在している。したがって、本実施形態の凹面ミラー１３０は、放物面形状の反射板で構成されている。ＬＥＤ１７は、その発光面１７ａ上に凹面ミラー１３０の焦点Ｐが位置するように配置され、任意の固定用部材（図示略）等を用いて固定されている。 Referring to FIGS. 9A and 9B, the light source 129 of the present embodiment includes the LED 17 and the concave mirror 130, and does not include a cylindrical lens. That is, an air layer is present in the present embodiment in the region where the cylindrical lens 18 between the LED 17 and the concave mirror 19 was present in the first embodiment. Therefore, the concave mirror 130 of the present embodiment is configured by a parabolic reflector. The LED 17 is disposed so that the focal point P of the concave mirror 130 is positioned on the light emitting surface 17a, and is fixed using an arbitrary fixing member (not shown) or the like.
　本実施形態の面光源装置においても、全ての方位角において高い指向性を持つ光が得られる、という第１実施形態と同様の効果を得ることができる。本実施形態の場合、シリンドリカルレンズを用いない分、面光源装置のコストを削減することができる。また、光がシリンドリカルレンズを透過する際の損失が生じないため、輝度が高い面光源装置を提供することができる。 Also in the surface light source device of the present embodiment, it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles. In the case of the present embodiment, the cost of the surface light source device can be reduced by not using a cylindrical lens. In addition, since no loss occurs when light passes through the cylindrical lens, a surface light source device with high luminance can be provided.
［第６実施形態］
　以下、本発明の第６実施形態について、図１０を用いて説明する。
　本実施形態の面光源装置の基本構成は第１実施形態と同様であり、光源部の構成が第１実施形態と異なる。
　図１０は、本実施形態の面光源装置の光源部を導光体の光入射面（端面）側から見た正面図であり、第１実施形態の図５に相当する図である。図１０において図５と共通の構成要素には同一の符号を付し、説明を省略する。 [Sixth Embodiment]
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the surface light source device of this embodiment is the same as that of the first embodiment, and the configuration of the light source unit is different from that of the first embodiment.
FIG. 10 is a front view of the light source unit of the surface light source device of the present embodiment as viewed from the light incident surface (end surface) side of the light guide, and corresponds to FIG. 5 of the first embodiment. In FIG. 10, the same components as those in FIG.
　第１実施形態の光源部１２は、図５に示すように、複数の光源１６が、光の伝播方向と直交する方向（ｙ軸方向）に１列に配列された構成であった。これに対して、本実施形態の光源部１３２は、図１０に示すように、複数の光源１３３Ａ，１３３Ｂが光の伝播方向と直交する方向（ｙ軸方向）に配列された光源群が、導光体の第１主面の法線方向（ｚ軸方向）に２列設けられている。 As shown in FIG. 5, the light source unit 12 of the first embodiment has a configuration in which a plurality of light sources 16 are arranged in a line in a direction (y-axis direction) orthogonal to the light propagation direction. On the other hand, as shown in FIG. 10, the light source unit 132 of the present embodiment includes a light source group in which a plurality of light sources 133A and 133B are arranged in a direction (y-axis direction) orthogonal to the light propagation direction. Two rows are provided in the normal direction (z-axis direction) of the first main surface of the light body.
　１列の光源群を構成する複数の光源１３３Ａ，１３３Ｂは、シリンドリカルレンズ１３４Ａ，１３４Ｂの幅（配列方向の寸法）が異なる２種類の光源を含んでいる。そして、シリンドリカルレンズ１３４Ａの幅が大きい光源１３３Ａと、シリンドリカルレンズ１３４Ｂの幅が小さい光源１３３Ｂと、が交互に配置されている。 The plurality of light sources 133A and 133B constituting the light source group in one row include two types of light sources having different widths (dimensions in the arrangement direction) of the cylindrical lenses 134A and 134B. The light source 133A having a large width of the cylindrical lens 134A and the light source 133B having a small width of the cylindrical lens 134B are alternately arranged.
　光源１３３Ａ，１３３Ｂの配列方向において同じ位置にある光源を見ると、シリンドリカルレンズ１３４Ａの幅が大きい光源１３３Ａの上方には、シリンドリカルレンズ１３４Ｂの幅が小さい光源１３３Ｂが配置されている。シリンドリカルレンズ１３４Ｂの幅が小さい光源１３３Ｂの上方には、シリンドリカルレンズ１３４Ａの幅が大きい光源１３３Ａが配置されている。また、同じ位置にある上下２つの光源１３３Ａ，１３３Ｂは、シリンドリカルレンズ１３４Ａ，１３４Ｂの幅は異なるが、ＬＥＤ１７は同一直線上に配置されている。ＬＥＤ１７は、上下の列で共通の１つのＬＥＤを用いても良いし、上下の列で別個のＬＥＤを用いても良い。 When a light source located at the same position in the arrangement direction of the light sources 133A and 133B is viewed, a light source 133B having a small width of the cylindrical lens 134B is disposed above the light source 133A having a large width of the cylindrical lens 134A. A light source 133A having a large width of the cylindrical lens 134A is disposed above the light source 133B having a small width of the cylindrical lens 134B. Further, the upper and lower light sources 133A and 133B at the same position are different in the width of the cylindrical lenses 134A and 134B, but the LEDs 17 are arranged on the same straight line. As the LED 17, one common LED may be used in the upper and lower rows, or separate LEDs may be used in the upper and lower rows.
　本実施形態の面光源装置においても、全ての方位角において高い指向性を持つ光が得られる、という第１実施形態と同様の効果を得ることができる。本実施形態の場合、シリンドリカルレンズ１３４Ａ，１３４Ｂの幅が異なる光源１３３Ａ，１３３Ｂが上下で重ね合わされているため、仮に個々の光源の中央部と周縁部とで輝度ムラがあったとしても、全体としては輝度ムラが緩和されるという効果が得られる。 Also in the surface light source device of the present embodiment, it is possible to obtain the same effect as in the first embodiment that light having high directivity can be obtained at all azimuth angles. In the case of the present embodiment, the light sources 133A and 133B having different widths of the cylindrical lenses 134A and 134B are overlapped on the upper and lower sides, so that even if there is luminance unevenness between the central part and the peripheral part of each light source, as a whole Has an effect of reducing unevenness in luminance.
［第７実施形態］
　以下、本発明の第７実施形態について、図１１を用いて説明する。
　本実施形態の面光源装置の基本構成は第１実施形態と同様であり、光源部の構成が第１実施形態と異なる。
　図１１は、本実施形態の面光源装置の光源部を導光体の光入射面（端面）側から見た正面図であり、第１実施形態の図５に相当する図である。図１１において図５と共通の構成要素には同一の符号を付し、説明を省略する。 [Seventh Embodiment]
The seventh embodiment of the present invention will be described below with reference to FIG.
The basic configuration of the surface light source device of this embodiment is the same as that of the first embodiment, and the configuration of the light source unit is different from that of the first embodiment.
FIG. 11 is a front view of the light source unit of the surface light source device of the present embodiment as viewed from the light incident surface (end surface) side of the light guide, and corresponds to FIG. 5 of the first embodiment. In FIG. 11, the same reference numerals are given to the same components as those in FIG.
　本実施形態の光源部１３７は、図１１に示すように、複数の光源１３８が光の伝播方向と直交する方向（ｙ軸方向）に配列された光源群が、導光体の第１主面の法線方向（ｚ軸方向）に２列設けられている。第６実施形態と異なり、１列の光源群を構成する複数の光源１３８は全て寸法が同一である。すなわち、シリンドリカルレンズ１４０は全て寸法が同一である。上列において隣り合う２つの光源１３８の境界の位置が下列においてはＬＥＤ１３９の位置に対応し、下列において隣り合う２つの光源１３８の境界の位置が上列においてはＬＥＤ１３９の位置に対応している。すなわち、光の伝播方向と直交する方向（ｙ軸方向）における光源１３８の配列の繰り返しピッチを１ピッチとすると、上列の複数の光源１３８の配置と下列の複数の光源１３８の配置とは、１／２ピッチずれている。したがって、上下２列を合わせると、光源１３８の幅（ｙ軸方向の寸法）が同じ場合、本実施形態の光源部１３７のＬＥＤ１３９のピッチは第１実施形態の光源部１２のＬＥＤ１７のピッチの１／２となる。 As shown in FIG. 11, the light source unit 137 of the present embodiment includes a light source group in which a plurality of light sources 138 are arranged in a direction (y-axis direction) orthogonal to the light propagation direction. Two rows are provided in the normal direction (z-axis direction). Unlike the sixth embodiment, the plurality of light sources 138 constituting one row of light source groups all have the same dimensions. That is, the cylindrical lenses 140 are all the same size. The position of the boundary between two light sources 138 adjacent in the upper row corresponds to the position of the LED 139 in the lower row, and the position of the boundary between two light sources 138 adjacent in the lower row corresponds to the position of the LED 139 in the upper row. That is, when the repetition pitch of the arrangement of the light sources 138 in the direction orthogonal to the light propagation direction (y-axis direction) is 1 pitch, the arrangement of the plurality of light sources 138 in the upper row and the arrangement of the plurality of light sources 138 in the lower row are: There is a ½ pitch shift. Accordingly, when the two upper and lower rows are combined, if the width (dimension in the y-axis direction) of the light source 138 is the same, the pitch of the LEDs 139 of the light source unit 137 of this embodiment is 1 of the pitch of the LEDs 17 of the light source unit 12 of the first embodiment. / 2.
　本実施形態の面光源装置においても、全ての方位角において高い指向性を持つ光が得られる、という第１実施形態と同様の効果を得ることができる。本実施形態の場合、上述したように、ＬＥＤ１３９のピッチが実質的に狭まることになるため、全体として輝度ムラが緩和されるという効果が得られる。
［第８実施形態］ Also in the surface light source device of the present embodiment, the same effect as in the first embodiment that light having high directivity can be obtained in all azimuth angles can be obtained. In the case of the present embodiment, as described above, the pitch of the LEDs 139 is substantially narrowed, so that the effect of reducing luminance unevenness as a whole is obtained.
[Eighth Embodiment]
　以下、本発明の第８実施形態について説明する。本実施形態では、例えば液晶表示装置のバックライトの入光用光源として好適な光源装置の一例を示す。図１２は、本実施形態の光源装置を示す斜視図である。図１３Ａは、図１のＡ－Ａ’線に沿う断面図である。図１３Ｂは、図１２のＢ－Ｂ’線に沿う断面図である。なお、以下の各図面においては各構成要素を見やすくするため、構成要素によって寸法の縮尺を異ならせて示すことがある。 Hereinafter, an eighth embodiment of the present invention will be described. In the present embodiment, an example of a light source device suitable as a light source for incident light of a backlight of a liquid crystal display device, for example, is shown. FIG. 12 is a perspective view showing the light source device of the present embodiment. 13A is a cross-sectional view taken along line A-A ′ of FIG. 13B is a cross-sectional view taken along line B-B ′ of FIG. In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.
　本実施形態の光源装置２１は、図１２に示すように、光源部２２と、凹面ミラー２３と、ハーフミラー２４と、から構成されている。凹面ミラー２３は、光源部２２から射出された光を反射面でほぼ平行光として主面から射出させる機能を有する。ハーフミラー２４は、光源部２２から射出された光の一部を透過して凹面ミラー２３に入射させ、残りの光は反射させて進行方向を変更させた後に凹面ミラー２３に入射させる機構を有する。光源部２２はＬＥＤである。 The light source device 21 of the present embodiment includes a light source unit 22, a concave mirror 23, and a half mirror 24 as shown in FIG. The concave mirror 23 has a function of emitting light emitted from the light source unit 22 from the main surface as substantially parallel light on the reflecting surface. The half mirror 24 has a mechanism that transmits a part of the light emitted from the light source unit 22 to be incident on the concave mirror 23, reflects the remaining light, changes the traveling direction, and then enters the concave mirror 23. . The light source unit 22 is an LED.
　凹面ミラー２３は、シリンドリカルレンズ２５（凹レンズ）と、ミラー２６と、を備えている。シリンドリカルレンズ２５は、例えばアクリル樹脂等の樹脂で構成されている。シリンドリカルレンズ２５は、一方が凹面、他方が平坦面となったレンズ、いわゆる平凹レンズである。シリンドリカルレンズ２５を図中のｘｙ平面で切断した断面形状を見ると、図１３Ａに示すように、凹面のうち、湾曲面２５ｂは焦点Ｐを有する曲線形状を有している。本実施形態の場合、具体的には、湾曲面２５ｂの断面形状は放物線状である。一方、シリンドリカルレンズ２５をｘｚ平面で切断した断面形状を見ると、図１３Ｂに示すように、湾曲面２５ｂは直線形状である。すなわち、シリンドリカルレンズ２５の湾曲面２５ｂは、ｘｙ平面内において湾曲し、ｘｙ平面内においては湾曲していない放物面である。 The concave mirror 23 includes a cylindrical lens 25 (concave lens) and a mirror 26. The cylindrical lens 25 is made of a resin such as an acrylic resin. The cylindrical lens 25 is a so-called plano-concave lens having one concave surface and the other flat surface. Looking at the cross-sectional shape of the cylindrical lens 25 cut along the xy plane in the figure, the curved surface 25b of the concave surface has a curved shape having a focal point P as shown in FIG. 13A. In the case of this embodiment, specifically, the cross-sectional shape of the curved surface 25b is parabolic. On the other hand, when the cross-sectional shape obtained by cutting the cylindrical lens 25 along the xz plane is viewed, the curved surface 25b has a linear shape as shown in FIG. 13B. That is, the curved surface 25b of the cylindrical lens 25 is a paraboloid that is curved in the xy plane and not curved in the xy plane.
　シリンドリカルレンズ２５の湾曲面２５ｂに沿ってミラー２６が設けられている。ミラー２６は、シリンドリカルレンズ２５の湾曲面２５ｂに直接形成されたアルミニウムや銀等の光反射率の高い金属膜で構成されている。このように、シリンドリカルレンズ２５の湾曲面２５ｂとミラー２６とが密着しているため、ミラー２６の形状は湾曲面２５ｂの形状が反映された放物面となる。したがって、凹面ミラー２３の焦点の位置は、シリンドリカルレンズ２５の焦点の位置と一致する。焦点を図１３Ａに点Ｐで示す。なお、シリンドリカルレンズ２５の湾曲面２５ｂにミラー２６を直接形成する構成に代えて、シリンドリカルレンズとは別体に作製したミラー、たとえば樹脂に形成された誘電体ミラーを貼り合わせた構成としてもよい。 A mirror 26 is provided along the curved surface 25 b of the cylindrical lens 25. The mirror 26 is made of a metal film having a high light reflectivity such as aluminum or silver directly formed on the curved surface 25b of the cylindrical lens 25. Thus, since the curved surface 25b of the cylindrical lens 25 and the mirror 26 are in close contact, the shape of the mirror 26 is a paraboloid reflecting the shape of the curved surface 25b. Therefore, the focal position of the concave mirror 23 coincides with the focal position of the cylindrical lens 25. The focal point is indicated by point P in FIG. 13A. In place of the configuration in which the mirror 26 is directly formed on the curved surface 25b of the cylindrical lens 25, a configuration in which a mirror manufactured separately from the cylindrical lens, for example, a dielectric mirror formed in a resin, may be bonded.
　ハーフミラー２４は、ｚ軸と平行に、ｘｚ平面に対しては傾いて設置された２枚のハーフミラー２４ａとハーフミラー２４ｂから構成されている。本実施例では、それぞれｘｚ平面に対して４５°傾いているとする。図１４Ａ～図１４Ｃに示すように、それぞれのハーフミラーは透明基材２７上に反射部２８が形成されている構造を有している。本実施例では、透過率２０％、反射率８０％となるよう、反射部２８は透明基材２７の表面の８０％を被覆している。反射部２８は、透明基材２７と光源部２２の間に配置されている。反射部２８は、透明基材２７上にアルミニウムや銀等の光反射率の高い金属膜で形成されていても良いし、別の透明基材上に反射部２８が形成されている別体を透明基材２７に貼り合わせた構成としてもよい。また、反射部２８の形状は図１４Ａのようにドット状でも良いし、図１４Ｂのようにストライプ状でも良いし、図１４Ｃのように波状でも良い。本実施例においては、ハーフミラー２４ａとハーフミラー２４ｂの接線２４ｃと光源部２２のｘ軸に平行な中心線２２ｃを結んだ直線の中点に凹面ミラー２３の焦点Ｐが位置するようにハーフミラー２４と光源部２２を設置する。 The half mirror 24 is composed of two half mirrors 24a and 24b that are installed in parallel to the z axis and inclined with respect to the xz plane. In this embodiment, it is assumed that each is inclined 45 ° with respect to the xz plane. As shown in FIGS. 14A to 14C, each half mirror has a structure in which a reflective portion 28 is formed on a transparent base material 27. In the present embodiment, the reflecting portion 28 covers 80% of the surface of the transparent substrate 27 so that the transmittance is 20% and the reflectance is 80%. The reflection unit 28 is disposed between the transparent base material 27 and the light source unit 22. The reflective portion 28 may be formed of a metal film having a high light reflectance such as aluminum or silver on the transparent base material 27, or a separate body in which the reflective portion 28 is formed on another transparent base material. It is good also as a structure bonded together on the transparent base material 27. FIG. Further, the shape of the reflecting portion 28 may be a dot shape as shown in FIG. 14A, a stripe shape as shown in FIG. 14B, or a wave shape as shown in FIG. 14C. In this embodiment, the half mirror is such that the focal point P of the concave mirror 23 is located at the midpoint of a straight line connecting the tangent line 24c of the half mirror 24a and the half mirror 24b and the center line 22c parallel to the x axis of the light source unit 22. 24 and the light source unit 22 are installed.
　光源部２２は、一般的なＬＥＤからなる。光源部２２は、白色ＬＥＤ、青色ＬＥＤ、紫外線ＬＥＤ等を備えていてもよい。ＬＥＤの配光分布は、正面方向ほど光度が大きく、極角が大きくなるにつれて光度が小さくなるランバート分布となっている。発光主面２２ａは凹面ミラー２３側に向いており、ＬＥＤから射出された光の大半は凹面ミラー２３もしくはハーフミラー２４に照射される。より具体的には、ＬＥＤからの射出光のうち、極角が大きい光は直接凹面ミラー２３に入射し、極角の小さい光はハーフミラー２４で透過もしくは反射された後に凹面ミラー２３に入射する。ハーフミラー２４で反射された光は極角が大きくなり、凹面ミラー２３の中心より遠い領域に照射される。 The light source unit 22 includes a general LED. The light source unit 22 may include a white LED, a blue LED, an ultraviolet LED, and the like. The light distribution of the LED is a Lambertian distribution in which the luminous intensity increases in the front direction and decreases as the polar angle increases. The light emitting main surface 22a faces the concave mirror 23 side, and most of the light emitted from the LED is applied to the concave mirror 23 or the half mirror 24. More specifically, of the light emitted from the LED, light having a large polar angle is directly incident on the concave mirror 23, and light having a small polar angle is incident on the concave mirror 23 after being transmitted or reflected by the half mirror 24. . The light reflected by the half mirror 24 has a large polar angle and is irradiated to a region far from the center of the concave mirror 23.
　光源部２２およびハーフミラー２４はいずれも凹面ミラー２３の焦点Ｐ近傍に位置しているため、光源部２２から直接凹面ミラーに入射した光も、ハーフミラー２４を透過もしくは反射した光も凹面ミラー２３によって反射されｘｚ平面に対してほぼ平行な方向に指向性を持って射出される。 Since both the light source unit 22 and the half mirror 24 are located in the vicinity of the focal point P of the concave mirror 23, neither the light directly incident on the concave mirror from the light source unit 22 nor the light transmitted or reflected by the half mirror 24 is concave mirror 23. And is emitted with directivity in a direction substantially parallel to the xz plane.
　射出面の照度がほぼ均一になるためには、光源部からの射出光束が高角側ほど大きく、正面方向は小さい方が望ましい。一般的なＬＥＤは、逆に正面方向の射出光束が大きく、高角側が小さいため、そのまま凹面ミラー２３に入射させると光源部に近い箇所ほど明るくなり、外側ほど暗くなる。これに対し、ハーフミラー２４で正面方向に射出された光束の一部を高角側に反射させることで、高い指向性を持たせたまま、面内で射出光を均一に射出することが可能になる。 In order for the illuminance on the exit surface to be substantially uniform, it is desirable that the emitted light beam from the light source unit be larger at the higher angle side and smaller in the front direction. A general LED, on the other hand, has a large emission light beam in the front direction and a small high angle side. Therefore, when it is incident on the concave mirror 23 as it is, the portion closer to the light source portion becomes brighter and the outer portion becomes darker. On the other hand, by reflecting a part of the light beam emitted in the front direction by the half mirror 24 to the high angle side, it becomes possible to emit the emitted light uniformly within the surface while maintaining high directivity. Become.
　本実施形態において、凹面ミラー２３と光源部２２の間は空気層が存在しているが、本実施形態はこの構成に限られない。実施形態１のシリンドリカルレンズ１８を備えていてもよい。この場合、ハーフミラー２４は、シリンドリカルレンズ１８によって固定されていてもよい。
 ［第９実施形態］　 In the present embodiment, an air layer exists between the concave mirror 23 and the light source unit 22, but the present embodiment is not limited to this configuration. The cylindrical lens 18 of the first embodiment may be provided. In this case, the half mirror 24 may be fixed by the cylindrical lens 18.
[Ninth Embodiment]
　以下、本発明の第９実施形態について、図１５を用いて説明する。本実施形態の光源装置の基本構成は第８実施形態と同様であり、光源部２２とハーフミラー２４の間にミラー２９を追加している点が第８実施形態と異なる。図１５は、本実施形態の面光源装置をｘｙ平面で切断した断面図であり、第８実施形態の図１３Ａに相当する図である。図１５において図１３Ａと共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, a ninth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light source device of this embodiment is the same as that of the eighth embodiment, and is different from the eighth embodiment in that a mirror 29 is added between the light source unit 22 and the half mirror 24. FIG. 15 is a cross-sectional view of the surface light source device of the present embodiment cut along the xy plane, and corresponds to FIG. 13A of the eighth embodiment. In FIG. 15, the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態においては、ハーフミラー２４ａとハーフミラー２４ｂの接線２４ｃと、光源部２２のｘ軸に平行な中心線２２ｃを結んだ直線上にミラー２９を設置する。ミラー２９を設置することで、光源部２２のうち中心線２２ｃよりもＹ方向において負の方向の領域２ｌから射出されてハーフミラー２４ｂに入射する光、および光源部のうち中心線２２ｃよりもＹ方向において正の方向の領域２ｒから射出されてハーフミラー２４ａに入射する光がなくなるため、より高い指向性を得ることができるようになる。
［第１０実施形態］ In the present embodiment, the mirror 29 is installed on a straight line connecting the tangent line 24 c of the half mirror 24 a and the half mirror 24 b and the center line 22 c parallel to the x axis of the light source unit 22. By installing the mirror 29, the light emitted from the region 21 in the negative direction in the Y direction from the center line 22c in the light source unit 22 and incident on the half mirror 24b, and the Y from the center line 22c in the light source unit. Since there is no light emitted from the region 2r in the positive direction and incident on the half mirror 24a, higher directivity can be obtained.
[Tenth embodiment]
　以下、本発明の第１０実施形態について、図１６を用いて説明する。本実施形態の光源装置の基本構成は第９実施形態と同様であり、凹面ミラー２３の周囲にミラー２１０を追加している点が第９実施形態と異なる。図１６は、本実施形態の光源装置の斜視図であり、第８実施形態の図１２に相当する図である。図１６において図１２および図１５と共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, a tenth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light source device of this embodiment is the same as that of the ninth embodiment, and is different from the ninth embodiment in that a mirror 210 is added around the concave mirror 23. FIG. 16 is a perspective view of the light source device of the present embodiment and corresponds to FIG. 12 of the eighth embodiment. In FIG. 16, the same components as those in FIGS. 12 and 15 are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態においては、ミラー２１０を凹面ミラー２３の射出面以外の周囲５面に設置する。ミラー２１０を設置することで、光源部２２から射出されて直接凹面ミラー２３に当たらなかった光を反射して凹面ミラー２３に当て、光源部２２から射出された全光束に対する凹面ミラーからの取出効率を向上させることが可能になる。凹面ミラー２３とミラー２１０は一体に成形されていてもよい。
［第１１実施形態］ In the present embodiment, the mirror 210 is installed on five surrounding surfaces other than the exit surface of the concave mirror 23. By installing the mirror 210, the light that is emitted from the light source unit 22 and does not directly hit the concave mirror 23 is reflected and applied to the concave mirror 23, and the extraction efficiency from the concave mirror with respect to the total luminous flux emitted from the light source unit 22 It becomes possible to improve. The concave mirror 23 and the mirror 210 may be integrally formed.
[Eleventh embodiment]
　以下、本発明の第１１実施形態について、図１７および１８を用いて説明する。本実施形態の光源装置の基本構成は第９実施形態と同様であり、凹面ミラー２３の形状が、第９実施形態の形状に対してミラー２９を通る平面で切断された形状に変更され、切断面にミラー２１１が設置されている点が異なる。図１７は、本実施形態の光源装置の斜視図であり、第８実施形態の図１２に相当する図である。また、図１８は第８実施形態の図１３Ａに相当する図である。図１７及び図１８において図１２及び図１３Ａと共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, an eleventh embodiment of the present invention will be described with reference to FIGS. The basic configuration of the light source device of the present embodiment is the same as that of the ninth embodiment, and the shape of the concave mirror 23 is changed to a shape cut by a plane passing through the mirror 29 with respect to the shape of the ninth embodiment. The difference is that a mirror 211 is installed on the surface. FIG. 17 is a perspective view of the light source device of the present embodiment, and corresponds to FIG. 12 of the eighth embodiment. FIG. 18 is a diagram corresponding to FIG. 13A of the eighth embodiment. 17 and 18, the same reference numerals are given to the same components as those in FIGS. 12 and 13A, and description thereof is omitted.
　本実施形態では、凹面ミラーの形状が第９実施形態の形状に対してミラー２９を通る平面で切断された形状の凹面ミラー２３Ａに変更されている。すなわち、本実施形態における凹面ミラー２３Ａは、第９実施形態における凹面ミラー２３を、凹面ミラー２３の対称軸を通る平面で切断した形状を有している。また、切断面にミラー２１１が新たに設置されている。凹面ミラーは半分になるが、光源部２２から射出された光線はミラー２１１によって折り返されて凹面ミラー２３Ａに当たるため、第９実施形態と同じ効果を得ることができる。 In this embodiment, the shape of the concave mirror is changed to a concave mirror 23A having a shape cut by a plane passing through the mirror 29 with respect to the shape of the ninth embodiment. That is, the concave mirror 23A in the present embodiment has a shape obtained by cutting the concave mirror 23 in the ninth embodiment along a plane that passes through the axis of symmetry of the concave mirror 23. A mirror 211 is newly installed on the cut surface. Although the concave mirror is halved, the light beam emitted from the light source unit 22 is folded back by the mirror 211 and hits the concave mirror 23A. Therefore, the same effect as in the ninth embodiment can be obtained.
　本発明者らは、本実施形態の光源装置を前提として、凹面ミラーから射出される光の輝度－角度プロファイルおよび輝度－空間プロファイルに関する光学シミュレーションを行った。凹面ミラー２３の曲率半径を２．０ｍｍ、凹面ミラー２３のｙ方向の幅を４．０ｍｍ、光源部２２のｙ方向の幅を０．２ｍｍ、ハーフミラー２４の長さを０．２８３ｍｍ、ハーフミラー２４とｘｚ平面のなす角を４５°、光源部２２の光射出面と焦点Ｐの距離およびハーフミラー２４とミラー２９の接点と焦点Ｐとの距離をそれぞれ０．１ｍｍとしてモンテカルロ法による光線追跡シミュレーションを行った。図８Ａはハーフミラー２９が無く、焦点位置に光源部２２の光射出面がある場合の輝度－角度プロファイル、図８Ｂは本実施形態の輝度－角度プロファイル、図９Ａはハーフミラー２９が無く、焦点位置に光源部２２の光射出面がある場合の輝度－空間プロファイル、図８Ｂは本実施形態の輝度－空間プロファイルである。図８Ａおよび図８Ｂの比較より、ハーフミラー２９の有無で光線の存在する角度範囲がほとんど変わっていないにもかかわらず、図９Ａおよび図９Ｂの比較より、空間的な輝度の均一性が大きく向上していることがわかり、本実施形態の有効性が実証されている。
　［第１２実施形態］ Based on the premise of the light source device of the present embodiment, the present inventors performed an optical simulation regarding the luminance-angle profile and luminance-space profile of light emitted from the concave mirror. The radius of curvature of the concave mirror 23 is 2.0 mm, the width of the concave mirror 23 in the y direction is 4.0 mm, the width of the light source unit 22 in the y direction is 0.2 mm, the length of the half mirror 24 is 0.283 mm, and the half mirror Ray tracing simulation by the Monte Carlo method, where the angle formed by 24 and the xz plane is 45 °, the distance between the light exit surface of the light source unit 22 and the focal point P, and the distance between the contact point of the half mirror 24 and the mirror 29 and the focal point P is 0.1 mm. Went. 8A shows a luminance-angle profile when the half mirror 29 is not provided and the light exit surface of the light source unit 22 is at the focal position, FIG. 8B shows a luminance-angle profile according to this embodiment, and FIG. The luminance-space profile when the light exit surface of the light source unit 22 is at the position, FIG. 8B is the luminance-space profile of the present embodiment. Compared with FIG. 8A and FIG. 8B, the uniformity of spatial luminance is greatly improved over the comparison with FIG. 9A and FIG. This proves the effectiveness of the present embodiment.
[Twelfth embodiment]
　以下、本発明の第１２実施形態について、図２１を用いて説明する。本実施形態の光源装置の基本構成は第８実施形態と同様であり、光源部２２がｘｚ平面と垂直な方向に射出面を持つ背中合わせの一組みのＬＥＤ２２ａおよびＬＥＤ２２ｂから構成されており、それぞれにハーフミラー２４ａおよびハーフミラー２４ｂがｘｚ平面とある角度を持って設置されている点が異なる。図２１は、第１実施形態の図１３Ａに相当する図である。図２１において図１３Ａと共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, a twelfth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light source device of the present embodiment is the same as that of the eighth embodiment, and the light source unit 22 is composed of a pair of back-to-back LEDs 22a and LEDs 22b each having an exit surface in a direction perpendicular to the xz plane. The difference is that the half mirror 24a and the half mirror 24b are installed at an angle with respect to the xz plane. FIG. 21 is a diagram corresponding to FIG. 13A of the first embodiment. In FIG. 21, the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態において、光源部２２Ａはｘｚ平面と垂直な方向に射出面を持つ背中合わせの一組みのＬＥＤ２２ａおよびＬＥＤ２２ｂから構成されており、それぞれにハーフミラー２４ａおよびハーフミラー２４ｂがｘｙ平面とある角度を持って設置されている。第１実施例と異なり、ＬＥＤ２２ａおよびＬＥＤ２２ｂの射出光束が大きい発光面の正面方向が高角側を向いているため、ハーフミラー２４ａおよびハーフミラー２４ｂの透過部の割合を高くすることで第１実施例と同様の効果を得ることができる。
 　［第１３実施形態］ In the present embodiment, the light source unit 22A is composed of a pair of back-to- back LEDs 22a and 22b each having an exit surface in a direction perpendicular to the xz plane, and each of the half mirror 24a and the half mirror 24b has an angle with the xy plane. It is installed. Unlike the first embodiment, since the front direction of the light emitting surface where the emitted light flux of the LED 22a and the LED 22b is large is directed to the high angle side, the ratio of the transmission portions of the half mirror 24a and the half mirror 24b is increased. The same effect can be obtained.
[Thirteenth embodiment]
　以下、本発明の第１３実施形態について、図２２、２３Ａ及び２３Ｂを用いて説明する。本実施形態の光源装置の基本構成は第８実施形態と同様であり、凹面ミラー２３Ｂが中心軸を通りｘｙ平面と直交するいかなる平面で切断しても曲面形状、例えば放物面形状を有する形状となっており、同時にハーフミラー２４Ｂも円錐形状になっている点が異なる。図２２は、本実施形態の光源装置の斜視図であり、第８実施形態の図１２に相当する図である。また、図２３Ａは第１実施形態の図１３Ａ、図２３Ｂは第１実施形態の図１３Ｂに相当する図であり、共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, a thirteenth embodiment of the present invention will be described with reference to FIGS. 22, 23A and 23B. The basic configuration of the light source device of the present embodiment is the same as that of the eighth embodiment. Even if the concave mirror 23B is cut along any plane that passes through the central axis and is orthogonal to the xy plane, it has a curved shape, for example, a parabolic shape. At the same time, the half mirror 24B is also conical. FIG. 22 is a perspective view of the light source device of the present embodiment, and corresponds to FIG. 12 of the eighth embodiment. Moreover, FIG. 23A is a figure equivalent to FIG. 13A of 1st Embodiment, FIG. 23B is a figure corresponded to FIG. 13B of 1st Embodiment, and attaches | subjects the same code | symbol to a common component, and abbreviate | omits description.
　本実施形態において、凹面ミラー２３Ｂは中心軸を通りｘｙ平面と直交するいかなる平面で切断しても曲面形状、例えば放物面形状を有する形状となっている。また、ハーフミラー２４Ｂは円錐形状となっている。第８実施形態がｘｚ平面に対してほぼ平行な方向に指向性を持ち、それと垂直な方向には拡散されて光が射出されるのに対し、本実施形態ではｙｚ平面にほぼ垂直な方向に射出され、全ての方位角において高い指向性を持った光を射出することが可能である。
［第１４実施形態］ In the present embodiment, the concave mirror 23B has a curved surface shape, for example, a parabolic shape, even if cut by any plane that passes through the central axis and is orthogonal to the xy plane. Further, the half mirror 24B has a conical shape. The eighth embodiment has directivity in a direction substantially parallel to the xz plane, and is diffused in the direction perpendicular thereto, and light is emitted. In the present embodiment, the light is emitted in a direction substantially perpendicular to the yz plane. It is possible to emit light having a high directivity at all azimuth angles.
[Fourteenth embodiment]
　以下、本発明の第１４実施形態について、図２４および２５を用いて説明する。本実施形態の光源装置２２１の基本構成は第１実施形態と同様であり、光源部２２Ｃの出射面がｘｙ平面と平行な方向を向いており、光源部２２Ｃの出射面と接する位置にテレセントリックレンズ２１２が形成されており、テレセントリックレンズ２１２の出射面が凹面ミラー２３の焦点Ｐに位置し、かつハーフミラー２４が形成されている点が異なっている。図２４は、本実施形態の光源装置の斜視図であり、第８実施形態の図１２に相当する図である。また、図２５は第８実施形態の図１３Ａに相当する図であり、共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, a fourteenth embodiment of the present invention will be described with reference to FIGS. The basic configuration of the light source device 221 of the present embodiment is the same as that of the first embodiment, and the exit surface of the light source unit 22C faces the direction parallel to the xy plane, and the telecentric lens is located at a position in contact with the exit surface of the light source unit 22C. 212, the exit surface of the telecentric lens 212 is located at the focal point P of the concave mirror 23, and the half mirror 24 is formed. FIG. 24 is a perspective view of the light source device of the present embodiment and corresponds to FIG. 12 of the eighth embodiment. FIG. 25 is a diagram corresponding to FIG. 13A of the eighth embodiment, and common components are denoted by the same reference numerals and description thereof is omitted.
　本実施形態において、光源部２２Ｃの射出部はｘｙ平面と平行であり、射出された光はテレセントリックレンズ２１２に入射し、ｘｙ平面と垂直な方向に射出される。テレセントリックレンズ２１２から射出された光はハーフミラー２４によって反射、もしくは透過した後、凹面ミラー２３によってｘｚ平面と平行な方向に指向性を持って射出される。第８実施形態に比べて光源装置２２１の光射出面に対して平行な面における光源部２２Ｃの面積が小さいため、光源部２２Ｃの影ができにくい。また、光源部２２Ｃの下面に放熱機構を設けやすく、冷却しやすいという特徴がある。 In this embodiment, the emission part of the light source part 22C is parallel to the xy plane, and the emitted light enters the telecentric lens 212 and is emitted in a direction perpendicular to the xy plane. The light emitted from the telecentric lens 212 is reflected or transmitted by the half mirror 24 and then emitted by the concave mirror 23 with directivity in a direction parallel to the xz plane. Compared to the eighth embodiment, since the area of the light source unit 22C in a plane parallel to the light exit surface of the light source device 221 is small, it is difficult to shadow the light source unit 22C. Further, there is a feature that it is easy to provide a heat dissipation mechanism on the lower surface of the light source unit 22C and to be easily cooled.
　テレセントリックレンズ２１２の入射部および射出部以外の面はアルミニウムや銀等の反射率の高い金属膜で覆われた反射部となっていてもよい。また、ハーフミラー２４とテレセントリックレンズ２１２が一体で形成されていてもよい。
［第１５実施形態］ Surfaces other than the entrance and exit of the telecentric lens 212 may be a reflector covered with a highly reflective metal film such as aluminum or silver. Further, the half mirror 24 and the telecentric lens 212 may be integrally formed.
[Fifteenth embodiment]
以下、本発明の第１５実施形態について、図２６を用いて説明する。本実施形態の光源装置の基本構成は第１実施形態と同様であり、光源部２２の背面にレンズ２４３が設置されている点が異なる。図２６は、第８実施形態の図１３Ａに相当する図である。図２６において図１３Ａと共通の構成要素には同一の符号を付し、説明を省略する。 The fifteenth embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of this embodiment is the same as that of the first embodiment, except that a lens 243 is installed on the back surface of the light source unit 22. FIG. 26 is a diagram corresponding to FIG. 13A of the eighth embodiment. In FIG. 26, the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態において、光源部２２の背面にレンズ２４３が設置されており、レンズ２４３は凹面ミラー２３から射出された光の広がりをより平行光に近付けるように曲率が調整されている。レンズ２４３を設置することで、より高い指向性を有した射出光を得ることができる。
［第１６実施形態］ In the present embodiment, a lens 243 is installed on the back surface of the light source unit 22, and the curvature of the lens 243 is adjusted so that the spread of light emitted from the concave mirror 23 is closer to parallel light. By installing the lens 243, emitted light having higher directivity can be obtained.
[Sixteenth Embodiment]
　以下、本発明の第１６実施形態について、図２７を用いて説明する。本実施形態の光源装置の基本構成は第８実施形態と同様であり、ハーフミラー２４の代わりにレンズ２４４が設置されている点が異なる。図２７は、第８実施形態の図１３Ａに相当する図である。図２７において図１３Ａと共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, a sixteenth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light source device of this embodiment is the same as that of the eighth embodiment, except that a lens 244 is installed instead of the half mirror 24. FIG. 27 is a diagram corresponding to FIG. 13A of the eighth embodiment. In FIG. 27, the same components as those in FIG. 13A are denoted by the same reference numerals, and description thereof is omitted.
　本実施例においては、光源部２２の前面にレンズ２４４が設置されている。レンズ２４４は４次関数で近似できる曲面を有し、光源部２２の正面方向に射出された光の進行方向を高角側へ変更する。これにより、高い指向性を持たせたまま、面内で射出光を均一に射出することが可能になる。
［第１７実施形態］ In the present embodiment, a lens 244 is installed on the front surface of the light source unit 22. The lens 244 has a curved surface that can be approximated by a quartic function, and changes the traveling direction of light emitted in the front direction of the light source unit 22 to the high angle side. This makes it possible to emit the emitted light uniformly within the surface while maintaining high directivity.
[Seventeenth embodiment]
　以下、本発明の第１７実施形態について、図２８～図２９を用いて説明する。本実施形態では、例えば液晶表示装置のバックライトとして用いて好適な面光源装置の一例を示す。図２８は、本実施形態の面光源装置を示す斜視図である。図２９は、図２８のＡ－Ａ’線に沿う断面図である。図２８及び図２９において、図１と共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, a seventeenth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an example of a surface light source device suitable for use as, for example, a backlight of a liquid crystal display device is shown. FIG. 28 is a perspective view showing the surface light source device of this embodiment. FIG. 29 is a cross-sectional view taken along line A-A ′ of FIG. 28 and 29, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.
　本実施形態の面光源装置２１３は、図２８および図２９に示すように、光源装置２１と、導光体１３と、プリズムシート１４（方向変更用部材、方向変更部材）と、から構成されている。導光体１３は、光源装置２１から射出された光を端面から入射させ、内部で伝播させる間に主面から射出させる機能を有する。プリズムシート１４は、導光体１３の主面から射出された光の進行方向を、主面の法線により近い方向に変更する機能を有する。光源装置２１は、第８実施形態と同じ構成の光源装置である。 As shown in FIGS. 28 and 29, the surface light source device 213 according to the present embodiment includes a light source device 21, a light guide 13, and a prism sheet 14 (direction changing member, direction changing member). Yes. The light guide 13 has a function of causing light emitted from the light source device 21 to enter from the end face and to be emitted from the main surface while propagating inside. The prism sheet 14 has a function of changing the traveling direction of the light emitted from the main surface of the light guide 13 to a direction closer to the normal line of the main surface. The light source device 21 is a light source device having the same configuration as that of the eighth embodiment.
　以下、上記構成の面光源装置２１３の作用について説明する。光源部２２から発せられた光Ｌは、一部は直接凹面ミラー２３に入射し、一部はハーフミラー２４を透過もしくは反射された後に凹面ミラー２３に入射し、いずれもｘｚ平面に平行な方向に指向性を持って射出される。一方で、ｘｙ平面に平行な方向には指向性を持たない状態となっている。次に、光入射端面１３ａから導光体１３に入射された光Ｌは、図２７に示すように、第１主面１３ｂ（光射出面）と第２主面１３ｃ（反射面）との間で反射を繰り返しつつ、導光体１３の内部を光の伝播方向Ｘ（図２７の右側）に向けて進行する。仮に第１主面と第２主面とが平行であったとすると、光が反射を繰り返しても、第１主面および第２主面への光の入射角は変化しない。ところが、本実施形態の場合、導光体１３は光入射端面１３ａ側から離れるにつれて厚みが徐々に薄くなる楔形であり、第１主面１３ｂに対して第２主面１３ｃが所定の傾斜角を有している。そのため、光Ｌは、第１主面１３ｂおよび第２主面１３ｃで反射する毎に第１主面１３ｂおよび第２主面１３ｃへの入射角が小さくなる。 Hereinafter, the operation of the surface light source device 213 configured as described above will be described. A part of the light L emitted from the light source unit 22 is directly incident on the concave mirror 23, and part of the light L is incident on the concave mirror 23 after being transmitted or reflected by the half mirror 24, both of which are parallel to the xz plane. Is injected with directivity. On the other hand, there is no directivity in a direction parallel to the xy plane. Next, as shown in FIG. 27, the light L incident on the light guide 13 from the light incident end surface 13a is between the first main surface 13b (light emission surface) and the second main surface 13c (reflection surface). The light guide 13 travels in the light propagation direction X (right side in FIG. 27) while repeating the reflection. Assuming that the first main surface and the second main surface are parallel, the incident angle of light on the first main surface and the second main surface does not change even if light is repeatedly reflected. However, in the case of the present embodiment, the light guide 13 has a wedge shape in which the thickness gradually decreases as the distance from the light incident end surface 13a increases, and the second main surface 13c has a predetermined inclination angle with respect to the first main surface 13b. Have. Therefore, each time the light L is reflected by the first main surface 13b and the second main surface 13c, the incident angle on the first main surface 13b and the second main surface 13c becomes small.
　ここで、例えば導光体１３を構成するアクリル樹脂の屈折率が１．５、空気の屈折率を１．０とすると、導光体１３の第１主面１３ｂ（光射出面）における臨界角、すなわち導光体１３を構成するアクリル樹脂と空気との界面における臨界角は、スネルの法則から４２°程度となる。導光体１３に入射した直後の光が第１主面１３ｂに入射した際、第１主面１３ｂへの光Ｌの入射角が臨界角である４２°よりも大きい間は全反射条件を満たすため、光Ｌは第１主面１３ｂで全反射する。その後、光Ｌが第１主面１３ｂと第２主面１３ｃとの間で反射を繰り返し、第１主面１３ｂへの光Ｌの入射角が臨界角である４２°よりも小さくなった時点で全反射条件を満たさなくなり、光Ｌは外部空間に射出される。 Here, for example, when the refractive index of the acrylic resin constituting the light guide 13 is 1.5 and the refractive index of air is 1.0, the critical angle on the first main surface 13b (light emission surface) of the light guide 13 is shown. That is, the critical angle at the interface between the acrylic resin constituting the light guide 13 and the air is about 42 ° from Snell's law. When light immediately after entering the light guide 13 enters the first main surface 13b, the total reflection condition is satisfied as long as the incident angle of the light L on the first main surface 13b is larger than 42 ° which is a critical angle. Therefore, the light L is totally reflected by the first main surface 13b. Thereafter, when the light L repeatedly reflects between the first main surface 13b and the second main surface 13c, the incident angle of the light L on the first main surface 13b becomes smaller than 42 ° which is a critical angle. The light L is emitted to the external space because the total reflection condition is not satisfied.
　すなわち、光Ｌは、第１主面１３ｂへの入射角が臨界角よりも大きい間は導光体１３の内部に閉じ込められ、第１主面１３ｂへの入射角が臨界角よりも小さくなった時点で第１主面１３ｂから順次射出される。光Ｌは第１主面１３ｂから射出される際に屈折するので、第１主面１３ｂへの入射角が４２°程度の光は、射出角が７０°程度の光となって射出される。このように、光の伝播方向Ｘに平行、かつ導光体１３の光射出面１３ｂに垂直な平面（ｘｚ平面）内で見たとき、光Ｌは導光体１３に入射した時点では指向性を持たないが、導光体１３から射出する時点では高い指向性を有することになる。 That is, the light L is confined inside the light guide 13 while the incident angle on the first main surface 13b is larger than the critical angle, and the incident angle on the first main surface 13b becomes smaller than the critical angle. At the time, the first main surface 13b is sequentially ejected. Since the light L is refracted when emitted from the first main surface 13b, light having an incident angle of about 42 ° to the first main surface 13b is emitted as light having an emission angle of about 70 °. Thus, when viewed in a plane (xz plane) parallel to the light propagation direction X and perpendicular to the light exit surface 13 b of the light guide 13, the light L is directional at the point of incidence on the light guide 13. However, at the time of emission from the light guide 13, it has high directivity.
　導光体１３から射出するときの光Ｌの射出角は７０°程度であり、光Ｌはかなり水平に近い方向に射出される。したがって、プリズムシート１４を用いて、導光体１３から射出された光Ｌを導光体１３の第１主面１３ｂの法線方向に近い方向に立ち上げる必要がある。具体的には、先端角θ２が３８．５°程度のプリズム構造体１１１を有するプリズムシート１４を用い、光Ｌを、プリズム構造体１１１の第１面１１１ａから入射させ、第２面１１１ｂで反射させることで、導光体１３の第１主面１３ｂに対して略法線方向に立ち上げることができる。本実施形態の面光源装置２１３においては、光源部２２から発せられた光を一部ハーフミラー２４で透過もしくは反射させた後に凹面ミラー２３で反射させることで、導光体１３の光射出面１３ｂに平行な平面（ｘｙ平面）内で高い指向性を持たせた後、導光体１３を透過させることで、光の伝播方向Ｘに平行、かつ導光体１３の光射出面１３ｂに垂直な平面（ｘｚ平面）内でも高い指向性を持たせることができる。さらに、高い指向性を持つ光を、プリズムシート１４を透過させることで、導光体１３の第１主面１３ｂの法線方向に取り出すことができる。その結果、全ての方位角において高い指向性を持つ光を得ることができる。
 ［第１８実施形態］ The emission angle of the light L when emitted from the light guide 13 is about 70 °, and the light L is emitted in a substantially horizontal direction. Therefore, it is necessary to use the prism sheet 14 to raise the light L emitted from the light guide 13 in a direction close to the normal direction of the first main surface 13 b of the light guide 13. Specifically, a prism sheet 14 having a prism structure 111 with a tip angle θ2 of about 38.5 ° is used, and light L is incident from the first surface 111a of the prism structure 111 and reflected by the second surface 111b. By doing so, the light guide 13 can be raised in a substantially normal direction with respect to the first main surface 13b. In the surface light source device 213 of the present embodiment, the light emitted from the light source unit 22 is partially transmitted or reflected by the half mirror 24 and then reflected by the concave mirror 23, whereby the light emitting surface 13b of the light guide 13 is obtained. After having high directivity in a plane parallel to (xy plane), the light guide 13 is transmitted, so that it is parallel to the light propagation direction X and perpendicular to the light exit surface 13 b of the light guide 13. High directivity can be provided even in a plane (xz plane). Furthermore, light having high directivity can be extracted in the normal direction of the first main surface 13 b of the light guide 13 by transmitting the light through the prism sheet 14. As a result, light having high directivity at all azimuth angles can be obtained.
[Eighteenth embodiment]
　以下、本発明の第１８実施形態について、図３０および３１を用いて説明する。本実施形態は、第１５実施形態の面光源装置の変形例をバックライトとして備えた液晶表示装置の一例である。図１２および図２９と共通の構成要素には同一の符号を付し、説明を省略する。 Hereinafter, an eighteenth embodiment of the present invention will be described with reference to FIGS. The present embodiment is an example of a liquid crystal display device provided with a modification of the surface light source device of the fifteenth embodiment as a backlight. Constituent elements common to FIGS. 12 and 29 are denoted by the same reference numerals, and description thereof is omitted.
　第１７実施形態においては、光源部２２は全て発光主面２２ａを凹面ミラー２３に向けて設置していたが、本実施形態においては図３０のように光源部２２と背中合わせに光源部２３９を設置する。光源部２３９の発光主面２３９ａは、導光体１３と対向するように配置される。光源部２３９から射出された光は、凹面ミラー２３に当たることなく直接導光体１３内に入射する。よって、光源部２２から射出された光は、第１７実施例で述べたように全方位に指向性を持って導光体１３から射出されるのに対し、光源部２３９から射出された光はｙｚ平面に平行な方向にのみ指向性を持ち、ｘｚ平面と平行な方向には拡散して導光体１３から射出される。この特性を利用し、光源部２２と光源部２３９を切り替えることで射出光の指向性を切り替えることが可能になる。図３１のように液晶パネル２４０と組み合わせることで、秘密性の高い情報を液晶パネル２４０に表示させる場合は光源部２２のみを点灯させて周囲からの覗き見を防止し、複数人で映像を見る場合には光源部２３９も合わせて点灯し、多視点に向けて光を発するという使い分けが可能になる。 In the seventeenth embodiment, all the light source units 22 are installed with the light emitting main surface 22a facing the concave mirror 23. However, in the present embodiment, the light source unit 239 is installed back-to-back with the light source unit 22 as shown in FIG. To do. The light emission main surface 239 a of the light source unit 239 is disposed so as to face the light guide 13. The light emitted from the light source unit 239 enters the light guide 13 directly without hitting the concave mirror 23. Therefore, the light emitted from the light source unit 22 is emitted from the light guide 13 with directivity in all directions as described in the seventeenth embodiment, whereas the light emitted from the light source unit 239 is It has directivity only in a direction parallel to the yz plane, diffuses in the direction parallel to the xz plane, and is emitted from the light guide 13. Using this characteristic, the directivity of the emitted light can be switched by switching between the light source unit 22 and the light source unit 239. In combination with the liquid crystal panel 240 as shown in FIG. 31, when displaying highly confidential information on the liquid crystal panel 240, only the light source unit 22 is turned on to prevent peeping from the surroundings, and a plurality of people view the video. In this case, the light source unit 239 is also turned on, and it is possible to selectively use light emitted from multiple viewpoints.
　液晶パネル２４０としては、例えばアクティブマトリクス方式の透過型液晶パネルを用いることができる。ただし、アクティブマトリクス方式の透過型液晶パネルに限らず、例えば半透過型（透過・反射兼用型）液晶パネル、各画素がスイッチング用薄膜トランジスタ（Ｔｈｉｎ　Ｆｉｌｍ　Ｔｒａｎｓｉｓｔｏｒ， 以下、ＴＦＴと略記する）を備えていない単純マトリクス方式の液晶パネルであっても良い。液晶パネル２４０には周知の一般的な液晶パネルを用いることができるため、詳細な構成の説明は省略する。ただし、特に液晶パネル２４０がＩＰＳ方式もしくはＦＦＳ方式など、初期の液晶配向が基板に対して平行で、平行方向に印加される電界によってスイッチングされる液晶パネルであった場合、複数人で見る場合も色ずれの少ない画像を観ることができるため、非常に有効である。 As the liquid crystal panel 240, for example, an active matrix transmissive liquid crystal panel can be used. However, the liquid crystal panel is not limited to the active matrix type transmissive liquid crystal panel. For example, each pixel does not include a switching thin film transistor (Thin Film Transistor, hereinafter abbreviated as TFT). A simple matrix type liquid crystal panel may be used. Since a well-known general liquid crystal panel can be used for the liquid crystal panel 240, detailed description of the configuration is omitted. However, especially when the liquid crystal panel 240 is a liquid crystal panel such as an IPS system or an FFS system, where the initial liquid crystal alignment is parallel to the substrate and is switched by an electric field applied in a parallel direction, This is very effective because an image with little color misregistration can be viewed.
　また、本実施例では光源部２３９を光源部２２と背中合わせに設置したが、発光主面２３９ａが導光体１３に向いていればよく、例えば隣接する凹面ミラー２３の境界部近傍に配置されていてもかまわない。 In this embodiment, the light source unit 239 is installed back-to-back with the light source unit 22. However, the light emission main surface 239a only needs to face the light guide 13, and is disposed, for example, in the vicinity of the boundary between adjacent concave mirrors 23. It doesn't matter.
［第１９実施形態］
　以下、本発明の第１９実施形態について、図３２及び図３３を用いて説明する。
　第１９～第２０実施形態では、上記実施形態の面光源装置を備えた表示装置の一例を示す。
　本実施形態においては、第１実施形態の面光源装置をバックライトとして備えた液晶表示装置の一例を図３２に示し、第１７実施形態の面光源装置をバックライトとして備えた液晶表示装置の一例を図３３に示す。 [Nineteenth Embodiment]
The nineteenth embodiment of the present invention will be described below with reference to FIGS. 32 and 33.
In the nineteenth to twentieth embodiments, an example of a display device including the surface light source device of the above embodiment is shown.
In this embodiment, an example of a liquid crystal display device provided with the surface light source device of the first embodiment as a backlight is shown in FIG. 32, and an example of a liquid crystal display device provided with the surface light source device of the seventeenth embodiment as a backlight. Is shown in FIG.
　本実施形態の液晶表示装置１４３は、図３２に示すように、バックライト１４４（面光源装置）と、第１偏光板１４５と、液晶パネル１４６と、第２偏光板１４７と、視野角拡大フィルム１４８と、から構成されている。なお、図３２では、液晶パネル１４６を模式的に１枚の板状に図示している。観察者は、視野角拡大フィルム１４８が配置された図３２における液晶表示装置１４３の上側から表示を見ることになる。よって、以下の説明では、視野角拡大フィルム１４８が配置された側を視認側と称し、バックライト１４４が配置された側を背面側と称する。
　また、図３３に示す液晶表示装置２２６は、液晶表示装置１４３と同様の構成を有し、バックライト１４４の代わりに、バックライト２１８を備える点が異なる。 As shown in FIG. 32, the liquid crystal display device 143 of this embodiment includes a backlight 144 (surface light source device), a first polarizing plate 145, a liquid crystal panel 146, a second polarizing plate 147, and a viewing angle widening film. 148. In FIG. 32, the liquid crystal panel 146 is schematically illustrated as a single plate. The observer views the display from the upper side of the liquid crystal display device 143 in FIG. 32 where the viewing angle widening film 148 is arranged. Therefore, in the following description, the side on which the viewing angle widening film 148 is disposed is referred to as a viewing side, and the side on which the backlight 144 is disposed is referred to as a back side.
A liquid crystal display device 226 illustrated in FIG. 33 has a configuration similar to that of the liquid crystal display device 143, and is different in that a backlight 218 is provided instead of the backlight 144.
　本実施形態の液晶表示装置１４３においては、バックライト１４４から射出された光を液晶パネル１４６で変調し、変調した光によって所定の画像や文字等を表示する。同様に、液晶表示装置２２６においては、バックライト２１８から射出された光を液晶パネル１４６で変調し、変調した光によって所定の画像や文字等を表示する。また、液晶パネル１４６から射出された光が視野角拡大フィルム１４８を透過すると、射出光の角度分布が視野角拡大フィルム１４８に入射する前よりも広がった状態となって光が視野角拡大フィルム１４８から射出される。これにより、観察者は広い視野角を持って表示を視認できる。 In the liquid crystal display device 143 of this embodiment, the light emitted from the backlight 144 is modulated by the liquid crystal panel 146, and a predetermined image, characters, or the like is displayed by the modulated light. Similarly, in the liquid crystal display device 226, light emitted from the backlight 218 is modulated by the liquid crystal panel 146, and a predetermined image, characters, or the like is displayed by the modulated light. Further, when the light emitted from the liquid crystal panel 146 passes through the viewing angle widening film 148, the angle distribution of the emitted light becomes wider than before entering the viewing angle widening film 148, and the light is widened. Is injected from. Thereby, the observer can visually recognize the display with a wide viewing angle.
　液晶パネル１４６としては、例えばアクティブマトリクス方式の透過型液晶パネルを用いることができる。ただし、アクティブマトリクス方式の透過型液晶パネルに限らず、例えば半透過型（透過・反射兼用型）液晶パネル、各画素がスイッチング用薄膜トランジスタ（Ｔｈｉｎ　Ｆｉｌｍ　Ｔｒａｎｓｉｓｔｏｒ， 以下、ＴＦＴと略記する）を備えていない単純マトリクス方式の液晶パネルであっても良い。液晶パネル１４６には周知の一般的な液晶パネルを用いることができるため、詳細な構成の説明は省略する。 As the liquid crystal panel 146, for example, an active matrix transmissive liquid crystal panel can be used. However, the liquid crystal panel is not limited to the active matrix type transmissive liquid crystal panel. For example, each pixel does not include a switching thin film transistor (Thin Film Transistor, hereinafter abbreviated as TFT). A simple matrix type liquid crystal panel may be used. Since a known general liquid crystal panel can be used as the liquid crystal panel 146, a detailed description of the configuration is omitted.
　液晶表示装置１４３及び液晶表示装置２２６の視認側には、視野角拡大フィルム１４８が配置されている。視野角拡大フィルム１４８は、基材１４９と、基材１４９の一面（視認側と反対側の面）に形成された複数の光拡散部１５０と、基材１４９の一面に形成された黒色層１５１（光吸収層）と、から構成されている。視野角拡大フィルム１４８は、光拡散部１５０が設けられた側を第２偏光板１４７に向け、基材１４９の側を視認側に向けた姿勢で第２偏光板１４７上に配置されている。 A viewing angle widening film 148 is disposed on the viewing side of the liquid crystal display device 143 and the liquid crystal display device 226. The viewing angle widening film 148 includes a base material 149, a plurality of light diffusion portions 150 formed on one surface of the base material 149 (surface opposite to the viewing side), and a black layer 151 formed on one surface of the base material 149. (Light absorption layer). The viewing angle widening film 148 is disposed on the second polarizing plate 147 in such a posture that the side where the light diffusion unit 150 is provided faces the second polarizing plate 147 and the base 149 side faces the viewing side.
　基材１４９には、例えばトリアセチルセルロース（ＴＡＣ）フィルム等の透明樹脂製の基材が好ましく用いられる。光拡散部１５０は、例えばアクリル樹脂やエポキシ樹脂等の光透過性および感光性を有する有機材料で構成されている。光拡散部１５０は、水平断面（ｘｙ断面）の形状が円形であり、光射出端面となる基材１４９側の面の面積が小さく、光入射面となる基材１４９と反対側の面の面積が大きく、基材１４９側から基材１４９と反対側に向けて水平断面の面積が徐々に大きくなっている。すなわち、光拡散部１５０は、基材１４９側から見たとき、いわゆる逆テーパ状の円錐台状の形状を有している。光拡散部１５０は、視野角拡大フィルム１４８において光の透過に寄与する部分である。すなわち、光拡散部１５０に入射した光は、光拡散部１５０のテーパ状の側面で全反射しつつ、光拡散部１５０の内部に略閉じこめられた状態で導光し、全方位に拡散した状態で射出される。 For the base material 149, for example, a base material made of a transparent resin such as a triacetyl cellulose (TAC) film is preferably used. The light diffusing unit 150 is made of an organic material having optical transparency and photosensitivity such as acrylic resin and epoxy resin. The light diffusing unit 150 has a circular horizontal cross section (xy cross section), has a small surface area on the base material 149 side serving as a light emission end face, and an area of a surface opposite to the base material 149 serving as a light incident surface. The area of the horizontal cross section gradually increases from the base material 149 side to the side opposite to the base material 149. That is, when viewed from the base material 149 side, the light diffusing unit 150 has a so-called reverse-tapered truncated cone shape. The light diffusion part 150 is a part that contributes to the transmission of light in the viewing angle widening film 148. That is, light incident on the light diffusing unit 150 is totally reflected by the tapered side surface of the light diffusing unit 150, guided in a state of being substantially confined inside the light diffusing unit 150, and diffused in all directions. It is injected at.
　黒色層１５１は、図４Ａに示すように、基材１４９の光拡散部１５０が形成された側の面のうち、複数の光拡散部１５０の形成領域以外の領域に形成されている。黒色層１５１は、一例として、ブラックレジスト等の光吸収性および感光性を有する有機材料で構成されている。 As shown in FIG. 4A, the black layer 151 is formed in a region other than the formation region of the plurality of light diffusion portions 150 on the surface of the base material 149 on the side where the light diffusion portions 150 are formed. As an example, the black layer 151 is made of an organic material having light absorption and photosensitivity such as a black resist.
　例えば画面の正面方向、すなわち液晶パネルを垂直に透過する光を基準として、液晶表示装置の画質の調整を行った場合、指向性を持たない従来のバックライトを用いた液晶表示装置では、画面を正面方向から見たときと斜め方向から見たときとで色ずれが生じてしまう。これに対して、本実施形態の液晶表示装置１４３では、正面方向に高い指向性を有する第１実施形態の面光源装置からなるバックライト１４４を用いている。また、液晶表示装置２２６では、正面方向に高い指向性を有する第１７実施形態の面光源装置からなるバックライト２１８を用いている。ため、液晶パネル１４６において色変化が少ない角度範囲のみを透過する。その後、視野角拡大フィルム１４８で光が全ての方位に拡散するため、観察者はどの方向から見ても色ずれの少ない高画質の映像を見ることができる。 For example, when the image quality of a liquid crystal display device is adjusted with reference to the front direction of the screen, that is, the light transmitted vertically through the liquid crystal panel, the screen is not displayed in a liquid crystal display device using a conventional backlight having no directivity. Color misregistration occurs when viewed from the front direction and when viewed from the oblique direction. On the other hand, in the liquid crystal display device 143 of this embodiment, the backlight 144 which consists of the surface light source device of 1st Embodiment which has high directivity in a front direction is used. Further, the liquid crystal display device 226 uses the backlight 218 made up of the surface light source device of the seventeenth embodiment having high directivity in the front direction. Therefore, the liquid crystal panel 146 transmits only the angle range with little color change. Thereafter, since the light is diffused in all directions by the viewing angle widening film 148, the observer can see a high-quality image with little color shift from any direction.
［第２０実施形態］
　以下、本発明の第２０実施形態について、図３４及び図３５を用いて説明する。
　本実施形態においては、第１実施形態の面光源装置をバックライトとして備えた蛍光励起型の液晶表示装置の一例を図３４に示し、第１７実施形態の面光源装置をバックライトとして備えた蛍光励起型の液晶表示装置の一例を図３５に示す。 [20th embodiment]
The twentieth embodiment of the present invention will be described below with reference to FIGS. 34 and 35.
In the present embodiment, an example of a fluorescence excitation type liquid crystal display device provided with the surface light source device of the first embodiment as a backlight is shown in FIG. 34, and the fluorescence provided with the surface light source device of the 17th embodiment as a backlight. An example of an excitation type liquid crystal display device is shown in FIG.
　本実施形態の液晶表示装置１５４は、図３４に示すように、バックライト１４４（面光源装置）と、液晶素子１５５、発光素子１５６と、を備えている。本実施形態の液晶表示装置１５４は、赤色光による表示を行う赤色用サブピクセル１５７Ｒ、緑色光による表示を行う緑色用サブピクセル１５７Ｇ、青色光による表示を行う青色用サブピクセル１５７Ｂが隣接して配置されており、これら３つのサブピクセル１５７Ｒ，１５７Ｇ，１５７Ｂにより表示を構成する最小単位である１つのピクセルが構成されている。
　また、図３５に示す液晶表示装置２２７は、液晶表示装置１５４と同様の構成を有し、バックライト１４４の代わりに、バックライト２１８を備える点が異なる。 As shown in FIG. 34, the liquid crystal display device 154 of this embodiment includes a backlight 144 (a surface light source device), a liquid crystal element 155, and a light emitting element 156. In the liquid crystal display device 154 of the present embodiment, a red subpixel 157R for displaying with red light, a green subpixel 157G for displaying with green light, and a blue subpixel 157B for displaying with blue light are arranged adjacent to each other. These three sub-pixels 157R, 157G, and 157B constitute one pixel that is a minimum unit that constitutes a display.
A liquid crystal display device 227 illustrated in FIG. 35 has a configuration similar to that of the liquid crystal display device 154, and is different in that a backlight 218 is provided instead of the backlight 144.
　バックライト１４４及び２１８は、発光素子１５６の蛍光体層１５８Ｒ，１５８Ｇ，１５８Ｂを励起させる励起光Ｌ１を射出するものであり、本実施形態では励起光Ｌ１として紫外光や青色光を射出する。液晶素子１５５は、バックライト１４４から射出された励起光Ｌ１の透過率を上記のサブピクセル１５７Ｒ，１５７Ｇ，１５７Ｂ毎に変調するものである。発光素子１５６には、液晶素子１５５により変調された励起光Ｌ１が入射され、蛍光体層１５８Ｒ，１５８Ｇ，１５８Ｂが励起されて発光した光が外部に射出される。したがって、本実施形態では、図１３に示す液晶表示装置１５４の上方側が、観察者が表示を見る視認側となる。 The backlights 144 and 218 emit excitation light L1 that excites the phosphor layers 158R, 158G, and 158B of the light emitting element 156. In the present embodiment, the backlights 144 and 218 emit ultraviolet light or blue light as the excitation light L1. The liquid crystal element 155 modulates the transmittance of the excitation light L1 emitted from the backlight 144 for each of the subpixels 157R, 157G, and 157B. Excitation light L1 modulated by the liquid crystal element 155 is incident on the light emitting element 156, and the phosphor layers 158R, 158G, and 158B are excited and emitted light is emitted to the outside. Therefore, in the present embodiment, the upper side of the liquid crystal display device 154 shown in FIG. 13 is the viewing side on which the observer views the display.
　液晶素子１５５は、第１透明基板１５９と第２透明基板１６０との間に液晶層１６１が挟持された構成となっている。本実施形態の場合、観察者から見て前面側に位置する第２透明基板１６０は、発光素子の基板を兼ねている。第１透明基板１５９の内面（液晶層１６１側の面）には、サブピクセル毎に第１透明電極１６２が形成され、第１透明電極１６２を覆うように配向膜（図示略）が形成されている。第１透明基板１５９の外面（液晶層１６１側と反対側の面）には第１偏光板１６３が設けられている。第１透明基板１５９には、例えばガラス、石英、プラスチック等からなる励起光を透過し得る基板を用いることができる。第１透明電極１６２には、例えばインジウム錫酸化物（Ｉｎｄｉｕｍ　Ｔｉｎ　Ｏｘｉｄｅ， 以下、ＩＴＯと略記する）等の透明導電性材料が用いられる。第１偏光板１６３には、従来一般の外付けの偏光板を用いることができる。 The liquid crystal element 155 has a configuration in which a liquid crystal layer 161 is sandwiched between a first transparent substrate 159 and a second transparent substrate 160. In the case of the present embodiment, the second transparent substrate 160 located on the front side as viewed from the observer also serves as a substrate of the light emitting element. On the inner surface of the first transparent substrate 159 (the surface on the liquid crystal layer 161 side), a first transparent electrode 162 is formed for each subpixel, and an alignment film (not shown) is formed so as to cover the first transparent electrode 162. Yes. A first polarizing plate 163 is provided on the outer surface of the first transparent substrate 159 (the surface opposite to the liquid crystal layer 161 side). As the first transparent substrate 159, a substrate made of glass, quartz, plastic, or the like that can transmit excitation light can be used. For the first transparent electrode 162, for example, a transparent conductive material such as indium tin oxide (Indium Tin Oxide, hereinafter abbreviated as ITO) is used. As the first polarizing plate 163, a conventional general external polarizing plate can be used.
　一方、第２透明基板１６０の内面（液晶層１６１側の面）には、蛍光体層１５８、第１光吸収層１６４が基板側からこの順に積層されている。蛍光体層１５８を構成する蛍光体材料は、サブピクセル毎に発光波長帯域が異なっている。バックライト１４４及び２１８からの励起光が紫外光である場合、赤色用サブピクセル１５７Ｒには紫外光を吸収して赤色光を発光する蛍光体材料からなる蛍光体層１５８Ｒが設けられる。同様に、緑色用サブピクセル１５７Ｇには紫外光を吸収して緑色光を発光する蛍光体材料からなる蛍光体層１５８Ｇが設けられる。青色用サブピクセル１５７Ｂには紫外光を吸収して青色光を発光する蛍光体材料からなる蛍光体層１５８Ｂが設けられる。 On the other hand, a phosphor layer 158 and a first light absorption layer 164 are laminated in this order from the substrate side on the inner surface (the surface on the liquid crystal layer 161 side) of the second transparent substrate 160. The phosphor material constituting the phosphor layer 158 has a different emission wavelength band for each subpixel. When the excitation light from the backlights 144 and 218 is ultraviolet light, the red subpixel 157R is provided with a phosphor layer 158R made of a phosphor material that absorbs ultraviolet light and emits red light. Similarly, the green subpixel 157G is provided with a phosphor layer 158G made of a phosphor material that absorbs ultraviolet light and emits green light. The blue subpixel 157B is provided with a phosphor layer 158B made of a phosphor material that absorbs ultraviolet light and emits blue light.
　もしくは、バックライト１４４及び２１８からの励起光が青色光である場合には、赤色用サブピクセル１５７Ｒ、緑色用サブピクセル１５７Ｇには青色光を吸収して赤色光、緑色光をそれぞれ発光する蛍光体材料からなる蛍光体層１５８Ｒ，１５８Ｇが設けられ、青色用サブピクセル１５７Ｂには、蛍光体層に代えて、励起光である青色光を波長変換することなく拡散させて外部に射出させる光拡散層が設けられる。さらに、第２透明基板１６０の内面には、光吸収層１６４を覆うように第２偏光板１６５が形成され、第２偏光板１６５の表面に第２透明電極１６６、配向膜（図示略）が積層されている。第２偏光板１６５は、液晶素子１５５の製造過程で塗布技術等を用いて作り込まれる偏光板であり、いわゆるイン・セル偏光板である。第２透明電極１６６には、第１透明電極１６２と同様、ＩＴＯ等の透明導電性材料が用いられる。 Alternatively, when the excitation light from the backlights 144 and 218 is blue light, the red subpixel 157R and the green subpixel 157G absorb the blue light and emit red light and green light respectively. Phosphor layers 158R and 158G made of a material are provided, and instead of the phosphor layer, the blue subpixel 157B diffuses the blue light as excitation light without converting the wavelength and emits the light to the outside. Is provided. Furthermore, a second polarizing plate 165 is formed on the inner surface of the second transparent substrate 160 so as to cover the light absorption layer 164, and a second transparent electrode 166 and an alignment film (not shown) are formed on the surface of the second polarizing plate 165. Are stacked. The second polarizing plate 165 is a so-called in-cell polarizing plate that is formed using a coating technique or the like in the manufacturing process of the liquid crystal element 155. For the second transparent electrode 166, a transparent conductive material such as ITO is used as in the case of the first transparent electrode 162.
　第２透明基板１６０の外面側には第２光吸収層１６７が形成されている。第２透明基板１６０の内面に設けられた第１光吸収層１６４は、バックライト１４４及び２１８からの励起光Ｌ１の漏れによるコントラスト低下を抑制するためのものである。第２透明基板１６０の外面に設けられた第２光吸収層１６７は、外光によるコントラスト低下を抑制するためのものである。 A second light absorption layer 167 is formed on the outer surface side of the second transparent substrate 160. The first light absorption layer 164 provided on the inner surface of the second transparent substrate 160 is for suppressing a decrease in contrast due to leakage of the excitation light L1 from the backlights 144 and 218. The second light absorption layer 167 provided on the outer surface of the second transparent substrate 160 is for suppressing a decrease in contrast due to external light.
　第１９実施形態で述べた通り、通常の液晶表示装置は、斜め方向から見たときに色ずれが生じる。これに対して、本実施形態の蛍光励起型の液晶表示装置１５４は、高い指向性を有する紫外光もしくは青色光の面光源装置をバックライト１４４として用い、紫外光もしくは青色光を蛍光体層１５８で色変換するものである。また、液晶表示装置２２７は、高い指向性を有する紫外光もしくは青色光の面光源装置をバックライト２１８として用い、紫外光もしくは青色光を蛍光体層１５８で色変換するものである。このとき、各色の光が蛍光体層１５８から等方的に射出されるため、観察者はどの方向から見ても色ずれの少ない高画質の映像を見ることができる。 As described in the nineteenth embodiment, an ordinary liquid crystal display device has a color shift when viewed from an oblique direction. On the other hand, the fluorescence excitation type liquid crystal display device 154 of the present embodiment uses an ultraviolet light or blue light surface light source device having high directivity as the backlight 144 and uses the ultraviolet light or blue light as the phosphor layer 158. Color conversion. In addition, the liquid crystal display device 227 uses an ultraviolet light or blue light surface light source device having high directivity as the backlight 218, and converts the color of the ultraviolet light or blue light by the phosphor layer 158. At this time, since the light of each color is isotropically emitted from the phosphor layer 158, the observer can see a high-quality image with little color shift from any direction.
［表示装置の構成例］
　以下、表示装置の一構成例について、図３６を用いて説明する。
　図３６は、表示装置の一構成例である液晶表示装置の概略構成を示す正面図である。 [Configuration example of display device]
Hereinafter, a configuration example of the display device will be described with reference to FIG.
FIG. 36 is a front view showing a schematic configuration of a liquid crystal display device which is one configuration example of the display device.
　本構成例の液晶テレビジョン１７５は、図３６に示すように、表示画面として上記第１９もしくは第２０実施形態の液晶表示装置１４３、２２６、１５４、または２２７を備えている。観察者側（図３６の手前側）には液晶パネルが配置され、観察者と反対側（図３６の奥側）にはバックライト（面光源装置）が配置されている。
　本構成例の液晶テレビジョン１７５は、上記実施形態の液晶表示装置１４３、２２６、１５４、または２２７を備えたことで、高い画質の液晶テレビジョンとなる。 As shown in FIG. 36, the liquid crystal television 175 of this configuration example includes the liquid crystal display device 143, 226, 154, or 227 of the nineteenth or twentieth embodiment as a display screen. A liquid crystal panel is disposed on the viewer side (front side in FIG. 36), and a backlight (surface light source device) is disposed on the side opposite to the viewer (back side in FIG. 36).
The liquid crystal television 175 of this configuration example includes the liquid crystal display device 143, 226, 154, or 227 of the above embodiment, and thus becomes a high quality liquid crystal television.
［照明装置の構成例］
　以下、照明装置の一構成例について、図３７及び３８を用いて説明する。
　図３７及び３８は、照明装置の概略構成を示す図である。
　図３７に示す照明装置の基本構成は第１実施形態の面光源装置と略同様であるため、図３７において第１実施形態の図２と共通な構成要素には同一の符号を付し、説明を省略する。また、図３８に示す照明装置の基本構成は第１７実施形態の面光源装置と略同様であるため、図３８において第１７実施形態の図２９と共通な構成要素には同一の符号を付し、説明を省略する。 [Configuration example of lighting device]
Hereinafter, a configuration example of the lighting device will be described with reference to FIGS.
37 and 38 are diagrams showing a schematic configuration of the illumination device.
The basic configuration of the illumination device shown in FIG. 37 is substantially the same as that of the surface light source device of the first embodiment. Therefore, in FIG. 37, the same components as those in FIG. Is omitted. Also, since the basic configuration of the illumination device shown in FIG. 38 is substantially the same as that of the surface light source device of the seventeenth embodiment, the same reference numerals in FIG. 38 denote the same components as in FIG. 29 of the seventeenth embodiment. The description is omitted.
　本構成例の照明装置１７６は、図３７に示すように、光源部１２と、導光体１３と、を備えている。すなわち、照明装置１７６は、図２に示した第１実施形態の面光源装置からプリズムシートを除いたものである。照明装置１７６はプリズムシートを備えていないため、照明装置１７６から発する光は、導光体１３の第１主面１３ｂ（光射出面）の法線方向に立ち上がることなく、第１主面１３ｂに対して大きな射出角で射出される。したがって、図１５に示すように、光源部１２を上方に向け、導光体１３を下方に向けた姿勢で照明装置１７６を設置すると、照明装置１７６の斜め下方に向けて光Ｌを照射することができる。
　また、図３８に示す照明装置２４２は、照明装置１７６と同様の構成を有し、光源部１２の代わりに、光源部２１を備える点が異なる。 As shown in FIG. 37, the illumination device 176 of this configuration example includes a light source unit 12 and a light guide 13. That is, the illumination device 176 is obtained by removing the prism sheet from the surface light source device of the first embodiment shown in FIG. Since the illuminating device 176 does not include a prism sheet, the light emitted from the illuminating device 176 does not rise in the normal direction of the first main surface 13b (light emission surface) of the light guide 13 and rises to the first main surface 13b. On the other hand, it is injected at a large injection angle. Accordingly, as shown in FIG. 15, when the lighting device 176 is installed with the light source unit 12 facing upward and the light guide 13 facing downward, the light L is emitted obliquely below the lighting device 176. Can do.
Also, the illumination device 242 illustrated in FIG. 38 has a configuration similar to that of the illumination device 176, and is different in that the light source unit 21 is provided instead of the light source unit 12.
　本構成例の照明装置１７６または２４２を、例えばホールの天井付近に設置すれば、照明装置１７６または２４２から下方に向けて指向性の高い光が照射されるので、スポットライトとして用いることができる。 If the lighting device 176 or 242 of this configuration example is installed near the ceiling of a hall, for example, light with high directivity is emitted downward from the lighting device 176 or 242 and can be used as a spotlight.
　なお、本発明の技術範囲は上記実施形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲において種々の変更を加えることが可能である。
　例えば上記第１～第１８実施形態においては、凹面ミラーの形状は放物面であると述べた。これに対し、上記の実施形態で用いることが可能な凹面ミラーの形状は、必ずしも放物面に限ることなく、放物面を含む概念として円錐曲面であれば良い。円錐曲面の頂点を通る断面の形状を示す曲線は二次曲線と呼ばれる。二次曲線は、円錐を任意の平面で切り取った断面から得られる曲線である。凹面ミラーの径方向の座標をρ、凹面ミラーの中心軸方向の座標をｚ、コーニック係数をｋとすると、二次曲線を下記の（１）式、（２）式で表すことができる。 The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first to eighteenth embodiments, it has been described that the shape of the concave mirror is a paraboloid. On the other hand, the shape of the concave mirror that can be used in the above embodiment is not necessarily limited to a paraboloid, and may be a conical curved surface as a concept including a paraboloid. A curve indicating the shape of a cross section passing through the apex of the conical curved surface is called a quadratic curve. A quadratic curve is a curve obtained from a cross section obtained by cutting a cone at an arbitrary plane. When the coordinate in the radial direction of the concave mirror is ρ, the coordinate in the central axis direction of the concave mirror is z, and the conic coefficient is k, the quadratic curve can be expressed by the following equations (1) and (2).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　（１）式、（２）式におけるコーニック係数ｋの値によって二次曲線の形状は変化する。二次曲線は、例えばｋ＝０のときに円となり、ｋ＝－０．２５のときに楕円曲線となり、ｋ＝－１のときに放物線となり、ｋ＝－２のときに双曲線となる。上記の実施形態では、これらの二次曲線をｘｙ平面における断面形状とする凹面ミラーを用いることができる。なお、第１実施形態でも述べたように、ＬＥＤからの光が到達する領域が少なくとも円錐曲面であれば良いので、ＬＥＤからの光が到達しない領域は例えば平坦な面であっても良い。 The shape of the quadratic curve changes depending on the value of the conic coefficient k in the equations (1) and (2). The quadratic curve is, for example, a circle when k = 0, an elliptic curve when k = −0.25, a parabola when k = −1, and a hyperbola when k = −2. In the above embodiment, it is possible to use a concave mirror having these quadratic curves as cross-sectional shapes in the xy plane. As described in the first embodiment, the region where the light from the LED reaches may be at least a conical curved surface, and the region where the light from the LED does not reach may be, for example, a flat surface.
　本発明の態様は、液晶表示装置、有機エレクトロルミネッセンス表示装置、プラズマディスプレイなどの各種表示装置、もしくはこれらの表示装置に用いられる面光源装置、もしくは各種照明装置に利用可能である。 The aspect of the present invention can be used for various display devices such as liquid crystal display devices, organic electroluminescence display devices, plasma displays, surface light source devices used in these display devices, or various illumination devices.
　本発明の態様は、液晶表示装置、ＭＥＭＳなどのシャッター機能を有する各種表示装置、もしくはこれらの表示装置に用いられる面光源装置、もしくは各種照明装置に利用可能である。 The aspect of the present invention can be used for various display devices having a shutter function such as a liquid crystal display device and MEMS, a surface light source device used for these display devices, or various illumination devices.
　１１，１１４…面光源装置、１３，１１５…導光体、１３ａ…端面（光入射面）、１３ｂ，１１５ｂ…第１主面（光射出面）、１３ｃ…第２主面（反射面）、１４…プリズムシート（方向変更用部材）、１６，１１９，１２３，１２９，１３３Ａ，１３３Ｂ，１３８…光源、１７，１２４，１３９…ＬＥＤ（発光素子）、１７ａ…発光面、１８，２５，１２０，１２５，１３４Ａ，１３４Ｂ，１４０…シリンドリカルレンズ（凸レンズ）、１９，２３，１３０…凹面ミラー、２１…光源装置、２２…光源部、２４…ハーフミラー、２６，２９，２１０，２１１…ミラー、２７…透明基材、２８…反射部、１１０，１２６…溝、１１６…プリズム構造体、１４３，１５４…液晶表示装置（表示装置）、１４４…バックライト（面光源装置）、１７５…液晶テレビジョン（表示装置）、１７６…照明装置、２１２…テレセントリックミラー、Ｐ…焦点。 DESCRIPTION OF SYMBOLS 11, 114 ... Surface light source device, 13, 115 ... Light guide, 13a ... End surface (light incident surface), 13b, 115b ... 1st main surface (light emission surface), 13c ... 2nd main surface (reflection surface), 14 ... Prism sheet (direction changing member), 16, 119, 123, 129, 133A, 133B, 138 ... Light source, 17, 124, 139 ... LED (light emitting element), 17a ... Light emitting surface, 18, 25, 120, 125, 134A, 134B, 140 ... cylindrical lens (convex lens), 19, 23, 130 ... concave mirror, 21 ... light source device, 22 ... light source unit, 24 ... half mirror, 26, 29, 210, 211 ... mirror, 27 ... Transparent substrate 28 ... Reflecting portion 110, 126 ... Groove, 116 ... Prism structure, 143, 154 ... Liquid crystal display device (display device), 144 ... Backlight (surface light source device), 75 ... liquid crystal television (display device), 176 ... lighting device, 212 ... telecentric mirror, P ... focus.

Claims (47)

  1. 　発光面を有する発光素子と前記発光素子から射出された光を反射する凹面ミラーとを少なくとも有する光源と、
    　前記光源から射出された光を端面から入射させ、内部で伝播させて主面から射出させる導光体と、を備え、
    　前記凹面ミラーは、前記導光体の主面に平行な平面で切断したときの断面形状が、焦点を有する曲線形状を少なくとも一部に有し、
    　前記発光素子は、前記発光面上に前記焦点が位置するように配置されるとともに、前記発光素子からの光が、前記凹面ミラーを介して前記導光体に入射される構成とされた面光源装置。     A light source having at least a light emitting element having a light emitting surface and a concave mirror that reflects light emitted from the light emitting element;
    A light guide that makes light emitted from the light source incident from an end face, propagates inside, and emits light from a main surface; and
    The concave mirror has, at least in part, a curved shape in which a cross-sectional shape when cut along a plane parallel to the main surface of the light guide has a focal point,
    The light emitting element is arranged such that the focal point is positioned on the light emitting surface, and a light source configured to allow light from the light emitting element to enter the light guide through the concave mirror apparatus.
  2. 　前記導光体は、前記光の伝播方向において前記主面に対して所定の傾斜角をなす反射面を有する請求項１に記載の面光源装置。 2. The surface light source device according to claim 1, wherein the light guide has a reflecting surface that forms a predetermined inclination angle with respect to the main surface in the light propagation direction.
  3. 　前記光源が、前記凹面ミラーの窪みに配置された凸レンズを備え、
    　前記凸レンズの焦点の位置が前記凹面ミラーの焦点の位置と略一致している請求項１に記載の面光源装置。     The light source includes a convex lens disposed in a recess of the concave mirror;
    The surface light source device according to claim 1, wherein a position of a focal point of the convex lens substantially coincides with a position of a focal point of the concave mirror.
  4. 　前記凹面ミラーが、前記凸レンズの凸面に形成された金属膜で構成されている請求項３に記載の面光源装置。 4. The surface light source device according to claim 3, wherein the concave mirror is made of a metal film formed on a convex surface of the convex lens.
  5. 　前記凸レンズの凸面と対向する面に溝が設けられ、前記溝の内部に前記発光素子が配置された請求項３に記載の面光源装置。 4. The surface light source device according to claim 3, wherein a groove is provided on a surface facing the convex surface of the convex lens, and the light emitting element is disposed inside the groove.
  6. 　前記導光体の主面に平行な平面で切断したときの前記溝の底部の断面形状が曲線状である請求項５に記載の面光源装置。 6. The surface light source device according to claim 5, wherein a cross-sectional shape of the bottom of the groove when cut along a plane parallel to the main surface of the light guide is curved.
  7. 　前記導光体の主面に垂直な平面で切断したときの前記凹面ミラーの断面形状が直線形状である請求項１に記載の面光源装置。 The surface light source device according to claim 1, wherein a cross-sectional shape of the concave mirror when cut along a plane perpendicular to the main surface of the light guide is a linear shape.
  8. 　前記導光体の端面に、前記光源が、前記主面に平行、かつ前記光の伝播方向に垂直な方向に複数並べて配置されている請求項１に記載の面光源装置。 The surface light source device according to claim 1, wherein a plurality of the light sources are arranged on the end face of the light guide in a direction parallel to the main surface and perpendicular to the light propagation direction.
  9. 　前記複数の光源が、前記主面に垂直な方向に複数列並べて配置されている請求項８に記載の面光源装置。 The surface light source device according to claim 8, wherein the plurality of light sources are arranged in a plurality of rows in a direction perpendicular to the main surface.
  10. 　一つの列を構成する前記複数の光源は、前記凹面ミラーの配列方向の寸法が異なる請求項９に記載の面光源装置。 The surface light source device according to claim 9, wherein the plurality of light sources constituting one row have different dimensions in the arrangement direction of the concave mirrors.
  11. 　複数の列を構成する前記複数の光源は、前記光源の配列方向における前記発光素子の位置が列毎に異なる請求項９に記載の面光源装置。 The surface light source device according to claim 9, wherein the plurality of light sources constituting the plurality of columns have different positions of the light emitting elements in the arrangement direction of the light sources for each column.
  12. 　前記導光体は、前記端面に近い側から前記端面から遠い側に向けて厚みが薄くなる楔形状を有し、前記主面と対向する面全体が前記反射面である請求項１に記載の面光源装置。 The said light guide has a wedge shape from which the thickness becomes thin toward the side far from the said end surface from the side close | similar to the said end surface, The whole surface facing the said main surface is the said reflective surface. Surface light source device.
  13. 　前記導光体が、前記主面と対向する面に複数のプリズム構造体を有し、前記プリズム構造体の一つの傾斜面が前記反射面である請求項１に記載の面光源装置。 The surface light source device according to claim 1, wherein the light guide has a plurality of prism structures on a surface facing the main surface, and one inclined surface of the prism structure is the reflection surface.
  14. 　さらに、前記導光体の主面から射出された光の進行方向を、前記主面の法線により近い方向に変更する方向変更部材を備える請求項１に記載の面光源装置。 Furthermore, the surface light source device of Claim 1 provided with the direction change member which changes the advancing direction of the light inject | emitted from the main surface of the said light guide to the direction close | similar to the normal line of the said main surface.
  15. 　請求項１に記載の面光源装置と、前記面光源装置から射出される光を用いて表示を行う表示素子と、を備えた表示装置。 A display device comprising: the surface light source device according to claim 1; and a display element that performs display using light emitted from the surface light source device.
  16. 　請求項１に記載の面光源装置を備えた照明装置。 A lighting device comprising the surface light source device according to claim 1.
  17. 　第１発光面を有する第１発光素子と、
    　前記第１発光素子から射出された光を反射する凹面ミラーと、
    　入射した光の少なくとも一部の進行方向を変える方向変更素子と、を備え、
    　前記凹面ミラーは、前記発光面に平行な平面で切断したときの断面形状が、焦点を有する曲線形状を少なくとも一部に有し、
    　前記焦点が、前記第１発光素子の前記第１発光面上、前記方向変更素子上、もしくは前記第１発光素子の前記第１発光面と前記方向変更素子を結んだ線上に位置するように前記第１発光素子が配置され、
    　前記第１発光素子からの光の少なくとも一部が前記方向変更素子により進行方向を変更され、前記凹面ミラーを介して出射される構成とされた光源装置。     A first light emitting element having a first light emitting surface;
    A concave mirror that reflects the light emitted from the first light emitting element;
    A direction changing element that changes a traveling direction of at least a part of incident light, and
    The concave mirror has, at least in part, a curved shape having a cross-sectional shape when cut along a plane parallel to the light emitting surface,
    The focal point is positioned on the first light emitting surface of the first light emitting element, on the direction changing element, or on a line connecting the first light emitting surface of the first light emitting element and the direction changing element. A first light emitting element is disposed;
    A light source device in which at least a part of light from the first light emitting element is changed in a traveling direction by the direction changing element and emitted through the concave mirror.
  18. 　前記方向変更素子が、入射した光の少なくとも一部を透過し、透過しなかった光を反射するハーフミラーである請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the direction changing element is a half mirror that transmits at least part of incident light and reflects light that has not been transmitted.
  19. 　前記曲線形状が放物面である請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the curved shape is a paraboloid.
  20. 　さらに、前記第１発光素子と前記方向変更素子の間に配置されたミラーを備える請求項１７に記載の光源装置。 The light source device according to claim 17, further comprising a mirror disposed between the first light emitting element and the direction changing element.
  21. 　さらに、前記凹面ミラーの曲線形状以外の面を囲うように配置されたミラーを備えている請求項１７に記載の光源装置。 The light source device according to claim 17, further comprising a mirror disposed so as to surround a surface other than the curved shape of the concave mirror.
  22. 　前記凹面ミラーが対称軸に沿って切断された曲線形状を有しており、対象軸上にミラーが設置されていることを特徴とする請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the concave mirror has a curved shape cut along a symmetry axis, and the mirror is installed on the target axis.
  23. 　前記凹面ミラーの曲線形状の中心軸を通るあらゆる平面で前記凹面ミラーを切断しても曲面形状である請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the concave mirror is curved even if it is cut along any plane passing through the central axis of the curved shape of the concave mirror.
  24. 　前記方向変更素子が円錐形状を有している請求項２３に記載の光源装置。 The light source device according to claim 23, wherein the direction changing element has a conical shape.
  25. 　前記第１発光面が前記凹面ミラーと対向する請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the first light-emitting surface faces the concave mirror.
  26. 　前記第１発光面が前記凹面ミラーの曲線形状の中心軸に対して平行である請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the first light emitting surface is parallel to a center axis of a curved shape of the concave mirror.
  27. 　前記第１発光素子が白色ＬＥＤである請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the first light emitting element is a white LED.
  28. 　前記第１発光素子が青色ＬＥＤである請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the first light emitting element is a blue LED.
  29. 　前記第１発光素子が紫外線ＬＥＤである請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the first light emitting element is an ultraviolet LED.
  30. 　前記ハーフミラーが透明基材と、前記透明基材上に形成された金属膜を含む反射部によって形成されている請求項１８に記載の光源装置。 The light source device according to claim 18, wherein the half mirror is formed of a transparent base and a reflective portion including a metal film formed on the transparent base.
  31. 　前記反射部がドット形状である請求項３０に記載の光源装置。 The light source device according to claim 30, wherein the reflection portion has a dot shape.
  32. 　前記反射部がストライプ形状である請求項３０に記載の光源装置。 The light source device according to claim 30, wherein the reflecting portion has a stripe shape.
  33. 　前記反射部が波状の形状である請求項３０に記載の光源装置。 The light source device according to claim 30, wherein the reflecting portion has a wave shape.
  34. 　前記光源装置と、
    　前記光源装置から射出された光を端面から入射させ、内部で伝播させて主面から射出させる導光体と、を備える面光源装置。     The light source device;
    A surface light source device comprising: a light guide that causes light emitted from the light source device to enter from an end surface, propagate inside, and exit from a main surface.
  35. 　前記導光体は、前記光の伝播方向において前記主面に対して所定の傾斜角をなす反射面を有する請求項３４に記載の面光源装置。 The surface light source device according to claim 34, wherein the light guide has a reflection surface that forms a predetermined inclination angle with respect to the main surface in the light propagation direction.
  36. 　前記導光体が前記端面に近い側から前記端面から遠い側に向けて厚みが薄くなる楔形状を有している請求項３４に記載の面光源装置。 35. The surface light source device according to claim 34, wherein the light guide has a wedge shape whose thickness decreases from a side close to the end face toward a side far from the end face.
  37. 　前記導光体の端面に、前記光源が、前記主面に平行、かつ前記光の伝播方向に垂直な方向に複数並べて配置されている請求項３４に記載の面光源装置。 35. The surface light source device according to claim 34, wherein a plurality of the light sources are arranged on the end face of the light guide in a direction parallel to the main surface and perpendicular to the light propagation direction.
  38. 　さらに、前記導光体の主面から射出された光の進行方向を、前記主面の法線により近い方向に変更する方向変更部材を備える請求項３４に記載の面光源装置。 35. The surface light source device according to claim 34, further comprising a direction changing member that changes a traveling direction of light emitted from the main surface of the light guide to a direction closer to a normal line of the main surface.
  39. 　請求項３４に記載の面光源装置と、前記面光源装置から射出される光を用いて表示を行う表示素子と、を備える表示装置。 A display device comprising: the surface light source device according to claim 34; and a display element that performs display using light emitted from the surface light source device.
  40. 　前記表示素子が視野角拡大フィルムを有する液晶パネルである請求項３９に記載の表示装置。 40. The display device according to claim 39, wherein the display element is a liquid crystal panel having a viewing angle widening film.
  41. 　前記表示素子が蛍光励起方式の液晶パネルである請求項３９に記載の表示装置。 40. The display device according to claim 39, wherein the display element is a fluorescence excitation type liquid crystal panel.
  42. 　さらに、前記導光体と対向する第２に発光面を有する第２発光素子を有し、
    　前記第１発光素子は、前記第１発光面が前記凹面ミラーと対向するように配置され、
    　前記第２発光素子は、前記第２発光面が前記導光体と対向するように配置される請求項３４に記載の面光源装置。     And a second light emitting element having a second light emitting surface facing the light guide,
    The first light emitting element is disposed such that the first light emitting surface faces the concave mirror,
    The surface light source device according to claim 34, wherein the second light emitting element is disposed such that the second light emitting surface faces the light guide.
  43. 　請求項４２に記載の面光源装置と、前記面光源装置から射出される光を用いて表示を行う表示素子と、を備えたことを特徴とする表示装置。 43. A display device comprising: the surface light source device according to claim 42; and a display element that performs display using light emitted from the surface light source device.
  44. 　前記表示素子は、液晶配向が基板に対して平行であり、平行方向に印加される電界によってスイッチングされる液晶パネルである請求項４３に記載の表示装置。 44. The display device according to claim 43, wherein the display element is a liquid crystal panel whose liquid crystal alignment is parallel to the substrate and is switched by an electric field applied in a parallel direction.
  45. 　さらに前記第１発光素子の背面にレンズが設置されている請求項１７に記載の光源装置。 The light source device according to claim 17, further comprising a lens disposed on a back surface of the first light emitting element.
  46. 　前記方向変更素子が、レンズである請求項１７に記載の光源装置。 The light source device according to claim 17, wherein the direction changing element is a lens.
  47. 　前記レンズが、４次関数で近似できる曲面を有している請求項４６に記載の光源装置。 The light source device according to claim 46, wherein the lens has a curved surface that can be approximated by a quartic function.
PCT/JP2012/060709 2011-04-28 2012-04-20 Light source device, surface light source device, display device, and illumination device WO2012147646A1 (en)

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