JP2014150082A - Light emitting element, light control element, display device and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element capable of suppressing luminous unevenness.SOLUTION: A light emitting element 102 includes a light source 103 and a reflecting surface 105a reflecting light emitted from the light source 103. When two directions orthogonally intersecting each other in a vertical plane relative to an optical axis CL of light reflected on the reflecting surface 105a are defined as a first direction (z direction) and a second direction (y direction), the diffusion angle of light in the first direction (z direction) and the diffusion angle of light in the second direction (y direction) are different each other.

Description

  The present invention relates to a light emitting element, a light control element, a display device, and a lighting device.

  As a sidelight type illumination device in which a light emitting element is disposed on an end face of a light guide, an illumination device of Patent Document 1 is known. In a sidelight type lighting device, in order to increase the luminance of illumination light, a plurality of light emitting elements are generally installed on the end face of a light guide. In this case, when the directivity of the light emitted from the light emitting element is high, light brightness and darkness may occur at the boundary portion between adjacent light emitting elements, which may cause uneven brightness. Therefore, in the illumination device of Patent Document 1, the light emitted from the light emitting element is diffused by the diffusion member so that a uniform amount of light can be obtained in the entire light guide.

JP 2001-52518 A

  In the illumination device of Patent Document 1, a diffusion member is installed between the light emitting element and the light guide. As a result, the number of parts increases, leading to an increase in cost. In addition, since light emitted from the light emitting element propagates while totally reflecting inside the light guide, the light emitted from the light emitting element is orthogonal to the light emitting surface of the light guide (the light guide plate). When diffused in the thickness direction), the light is not totally reflected. For this reason, light leakage occurs in the vicinity of the light incident surface of the light guide, resulting in uneven brightness.

  An object of the present invention is to provide a light emitting element, a light control element, a display device, and a lighting device that can suppress luminance unevenness.

  The light-emitting element of the present invention includes a light source and a reflection surface that reflects light emitted from the light source, and is orthogonal to each other in a plane perpendicular to the optical axis of the light reflected by the reflection surface. When the two directions are the first direction and the second direction, the light diffusion angle in the first direction and the light diffusion angle in the second direction are different from each other.

  The reflecting surface is an anamorphic reflecting surface having different curvatures of cross sections of the reflecting surface at points on the optical axis when the reflecting surface is cut by two planes orthogonal to each other including the optical axis. May be.

  The shape of the reflective surface in a cross section having a large curvature among the two cross sections may be a parabola, and the light source may be arranged at the focal point of the parabola.

  The curvature of the reflective surface in a cross section having a small curvature among the two cross sections may be zero.

  A package having a recess formed therein, wherein the reflecting surface is formed in the recess of the package, the recess is filled with a light transmitting member that transmits light emitted from the light source, and the light source is embedded in the light transmitting member May be.

  The plurality of light sources may be arranged in one direction, and the reflection surface corresponding to each light source may be provided in the package along the arrangement direction of the plurality of light sources.

  The light control device of the present invention includes a light guide having a light incident surface and a light exit surface, and a plurality of light emitting elements that allow light to enter the light incident surface of the light guide. Is provided with a plurality of light extraction areas along the light propagation direction, from which light propagated inside the light guide can be extracted to the outside of the light guide, and can be extracted from the plurality of light extraction areas The light propagation angles are different from each other, and the light emitted from the plurality of light emitting elements propagates through the light guide at different propagation angles, and the plurality of light emitting elements are the light emitting elements of the present invention, In the light-emitting element, the direction in which the light diffusion angle is large is a direction perpendicular to the normal line of the light exit surface of the light guide and the light propagation direction, and the direction in which the light diffusion angle is small is The direction is parallel to the normal of the light exit surface of the light guide.

  In the plurality of light extraction regions, the refractive indexes of the members in contact with the light exit surface of the light guide may be different from each other.

  The refractive index of the member in contact with the light exit surface of the light guide may be larger as it is disposed at a position farther from the light incident surface of the light guide.

  The light incident surface of the light guide is provided with a plurality of inclined surfaces having different angles with the light emitting surface of the light guide, and each of the plurality of light emitting elements is provided on each of the plurality of inclined surfaces. It may be fixed.

  Light in a direction orthogonal to the normal line of the light emitting surface of the light emitting element that emits light extracted from the light extraction region at a position relatively close to the light incident surface and orthogonal to the propagation direction of the light The diffusion angle of the light emitting element is orthogonal to the normal line of the light emitting surface of the light emitting element that emits light extracted from the light extraction region at a position relatively far from the light incident surface, and the light propagation direction. It may be larger than the light diffusion angle in the orthogonal direction.

  The display device of the present invention includes the light control element of the present invention and a display element that performs display using light emitted from the light control element.

  The illuminating device of this invention is equipped with the light control element of this invention.

  ADVANTAGE OF THE INVENTION According to this invention, the light emitting element, the light control element, display apparatus, and illuminating device which can suppress a brightness nonuniformity can be provided.

It is a perspective view of the backlight of a 1st embodiment. It is sectional drawing of the light emitting element with which a backlight is equipped. It is a figure which shows the structure of the concave mirror of a light emitting element. It is a figure which shows the light quantity distribution inside a light guide when the curvature of a concave mirror is changed. It is the perspective view of the backlight of 2nd Embodiment, and the enlarged view of a light emitting element. It is a figure which shows light quantity distribution inside a light guide. It is an enlarged view of the light emitting element with which the backlight of 3rd Embodiment was equipped. It is a disassembled perspective view of the liquid crystal display device provided with the backlight of 4th Embodiment. It is a figure for demonstrating the principle in which light inject | emits from each light extraction area | region of a backlight. It is a figure which shows the diffusion angle of the y direction of the light inject | emitted from each light emitting element. It is a disassembled perspective view which shows schematic structure of a liquid crystal display device. It is a figure which shows the example of arrangement | positioning of a backlight. It is a figure which shows the example of arrangement | positioning of a backlight. It is sectional drawing of the 1st structural example of an illuminating device. It is sectional drawing of the 2nd structural example of an illuminating device.

[First Embodiment]
FIG. 1 is a perspective view of a backlight (light control element) 100 according to the first embodiment.

  The backlight 100 includes a light guide 101 and a plurality of light emitting elements 102 that allow light to enter the light incident surface 101 a of the light guide 101.

  The light guide 101 is a transparent plate-like member having a rectangular shape in plan view. The end surface of the light guide 101 is a light incident surface 101a, and the main surface of the light guide 101 is a light exit surface 101b. In FIG. 1, the light emission surface 101 b is provided on both of the two main surfaces of the light guide 101, but the light emission surface 101 b may be provided only on one of the main surfaces of the light guide 101. Good. In FIG. 1, the light emitting surface 101b is a surface parallel to the xy plane, and the light incident surface 101a is a surface parallel to the yz plane. The plurality of light emitting elements 102 are arranged in the y direction along the light incident surface 101 a of the light guide 101. The plurality of light emitting elements 102 are fixed to the light incident surface 101 a of the light guide 101 with their light exit surfaces facing the light incident surface 101 a of the light guide 101. In FIG. 1, the plurality of light emitting elements 102 are provided only on one end face of the light guide 101, but the plurality of light emitting elements 102 are arranged on the end face facing the end face in the X direction. It is good also as a structure which injects light.

  Light that has entered the light incident surface 101 a of the light guide 101 from the light emitting element 102 propagates in the x direction while being totally reflected inside the light guide 101. Then, the optical path is converted by an optical path conversion member (not shown) provided on the two main surfaces of the light guide 101 and emitted from the light exit surface 101 b of the light guide 101. The amount of light emitted from the light exit surface 101 b of the light guide 101 is controlled by changing the amount of light emitted from the light emitting element 102. The light emitting elements 102 can be individually turned on and off, and can control the amount of emitted light. Thereby, the backlight 100 functions as a light control element capable of adjusting the amount of emitted light.

  FIG. 2 is a cross-sectional view of the light emitting element 102.

  The light emitting element 102 includes a package 104, a concave mirror 105, a light source 103, a reflection mirror 106, and a light transmission member 107. Symbol Pf is a focal point in a cross section parallel to the xz plane of the concave mirror 105, symbol Pc is a position (vertex) farthest from the light source 103 of the concave mirror 105, and symbol CL is a central axis (concave mirror) of the concave mirror 105. 105 is a line connecting the vertex Pc of 105 and the focal point Pf of the concave mirror 105). The central axis CL of the concave mirror 105 coincides with the optical axis of the light reflected by the concave mirror 105. Therefore, in the example of FIG. 2, the central axis CL coincides with the normal line (x axis) of the light emission surface 107 a of the light emitting element 102.

  The concave mirror 105 is provided in the concave portion 104 a of the package 104. The shape of the concave mirror 105 is a curved surface shape following the shape of the concave portion 104 a of the package 104. The concave mirror 105 is a parabolic mirror that reflects the light emitted from the light source 103. The shape of the concave portion 104a is formed by pressing a mold having a convex shape obtained by inverting the shape of the concave portion 104a to the surface of the resin member to be the package 104, for example. The shape of the recess 104a may be formed by cutting the surface of a flat resin member.

  The light source 103 is, for example, a substantially rectangular chip LED (surface mounting LED). The light source 103 is disposed at the focal point of the concave mirror 105. The central axis CL of the concave mirror 105 coincides with the normal line of the light emission surface of the light source 103 (the normal line of the upper surface of the chip LED).

  The concave portion 104 a of the package 104 is filled with a light transmitting member 107 that transmits light emitted from the light source 103. The light source 103 is embedded in the light transmitting member 107. The light transmitting member 107 is formed, for example, by forming the concave mirror 105 in the concave portion 104 a of the package 104, disposing the light source 103 and the reflecting mirror 106 inside the package 104, and then transmitting light such as acrylic resin inside the package 104. It is formed by injecting and curing a resin having the following. The refractive index of the light transmitting member 107 is set to the same value as the refractive index of the light guide 101. The surface 107 a exposed to the outside of the light transmitting member 107 is a light emitting surface of the light emitting element 102.

  The reflection mirror 106 is formed by forming a metal film such as aluminum on the mounting substrate of the light source 103 by sputtering or vapor deposition. The reflection mirror 106 reflects the light from the light source 103 emitted in a different direction from the concave mirror 105 toward the concave mirror 105.

  FIG. 3A is an enlarged view of the light emitting element 102. FIG. 3B is a diagram showing a cross section of the concave mirror 105 parallel to the xz plane and the angular distribution of the light reflected by the concave mirror 105 in the xz plane. FIG. 3C is a diagram showing a cross section of the concave mirror 105 parallel to the xy plane and the angular distribution of the light reflected by the concave mirror 105 in the xy plane.

  As shown in FIG. 3A, the concave mirror 105 is a parabolic mirror having a vertex Pc at a position farthest from the light source 103. The reflecting surface 105a of the concave mirror 105 is an anamorphic reflecting surface having different cross-sectional curvatures at the vertex Pc when the reflecting surface 105a is cut by two orthogonal planes including the central axis CL of the concave mirror 105. It is.

  The horizontal axis is the reflected light emission angle (the emission angle when it is emitted in the direction parallel to the central axis CL is 0 °), the vertical axis is the light amount emitted at the emission angle, and the light amount is A plane perpendicular to the optical axis of reflected light (the central axis CL of the concave mirror 105), with the absolute value | α−β | of the difference between the emission angles α and β when attenuated to 50% of the peak light quantity as the diffusion angle If two directions orthogonal to each other are defined as a first direction and a second direction, the light diffusion angles in the first direction and the second direction are different from each other. The direction in which the light diffusion angle is large is the direction (y direction) perpendicular to the normal line of the light exit surface 101b of the light guide 101 and perpendicular to the light propagation direction. This is a direction (z direction) parallel to the normal line of the light exit surface 101b of the light body 101.

  In the case of this embodiment, as shown in FIGS. 3B and 3C, the shape of the cross section parallel to the xz plane and the cross section parallel to the xy plane of the reflecting surface 105a is a parabola. The curvature of the parabola in the cross section 105B parallel to the xz plane of the reflective surface 105a is larger than the curvature of the parabola in the cross section 105A parallel to the xy plane of the reflective surface 105a. Therefore, the angular distribution of the light reflected by the reflecting surface 105a has a small spread in the z direction and a large spread in the y direction. In the xz plane, the emission angles when the light intensity attenuates to 50% of the peak light intensity are θ1 and θ2. Therefore, the diffusion angle D1 in the z direction is | θ1−θ2 |. In the xy plane, the emission angles when the light amount attenuates to 50% of the peak light amount are θ3 and θ4. Therefore, the diffusion angle D2 in the z direction is | θ3−θ4 |. Since the spread of light in the z direction is smaller than the spread of light in the y direction, the diffusion angle D1 in the z direction is smaller than the diffusion angle D2 in the y direction.

  In FIG. 3B and FIG. 3C, the focal point Pf is a parabolic focal point in a cross section parallel to the xz plane of the reflecting surface 105a. The curvature of the parabola in the cross section 105B parallel to the xz plane of the reflective surface 105a is different from the curvature of the parabola in the cross section 105A parallel to the xy plane of the reflective surface 105a. Therefore, the focal point Pf is different from the parabolic focal point in the cross section 105A parallel to the xy plane of the reflecting surface 105a. The light source 103 is disposed at a parabolic focal point Pf in a cross section 105B parallel to the xz plane of the reflecting surface 105a. Therefore, the light reflected by the reflecting surface 105a is substantially parallel light in a plane parallel to the xz plane, and the diffusion angle D1 is approximately 0 °.

  4 (a) to 4 (i) show the parabolic curvature C1 in the cross section parallel to the xz plane of the reflecting surface 105a fixed to 0.1 and the parabolic curvature in the cross section of the reflecting surface 105a parallel to the xy plane. It is a figure which shows the light quantity distribution inside a light guide when C2 is changed in 0.01 steps from 0.01 to 0.09. 4A to 4I, the upper side is a plan view of the light guide body 101 and the light emitting element 102 as viewed from the z direction, and the lower side is a cross section taken along the line AA ′ of the light guide body 101. FIG. It is a figure which shows light quantity distribution inside the light guide in.

  The spread of the light emitted from the light emitting element 102 in the y direction varies depending on the parabolic curvature C2 of the reflecting surface 105a in a cross section parallel to the xy plane. Increasing the curvature C2 reduces the spread of light in the y direction, and decreasing the curvature C2 increases the spread of light in the y direction. When the curvature C2 is 0.09, the light emitted from the light emitting element 102 is substantially parallel light when viewed from the z direction. A large light amount peak occurs at a position facing each light emitting element 102 in the AA ′ cross section of the light guide 101. Since the light does not spread sufficiently at the boundary between adjacent light emitting elements 102, the boundary becomes dark. Therefore, a large light quantity distribution is generated in the AA ′ cross section of the light guide 101. As the curvature C2 is reduced, light spreads to the boundary portion between the adjacent light emitting elements 102, and the boundary portion becomes brighter. Therefore, the light quantity distribution in the AA ′ cross section of the light guide 101 is made uniform.

  In the backlight 100 of this embodiment, the diffusion angle D1 in the z direction of the light emitted from the light emitting element 102 is smaller than the diffusion angle D2 in the y direction. Therefore, the spread of light in the z direction can be suppressed while allowing the spread of light in the y direction. When viewed in the xz plane, the light has a high directivity, so that the optical axis of the light emitting element 102 (the central axis CL of the concave mirror 105) is a critical angle with respect to the light exit surface 101b of the light guide 101. If the angle is set to the above angle, the amount of light leaking outside from the light exit surface 101b of the light guide 101 is very small. When viewed on the xy plane, the light has a large spread in the y direction and has a small directivity. Therefore, the light emitted from the light emitting element 102 spreads to the boundary between adjacent light emitting elements 102, and the boundary The amount of light increases. As a result, the light distribution is made uniform throughout the light guide, and the backlight has less luminance unevenness.

[Second Embodiment]
FIG. 5A is a perspective view of the backlight (dimming element) 111 according to the second embodiment, and FIG. 5B is an enlarged view of the light emitting element 110 provided in the backlight 111.

  The difference between the backlight 111 and the backlight 100 of the first embodiment is that the curvature of the cross section parallel to the xy plane of the reflecting surface 109a of the light emitting element 110 is set to zero. Constituent elements common to the backlight 100 of the first embodiment in the backlight 111 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The backlight 111 includes a light guide 101 and a plurality of light emitting elements 110 that allow light to enter the light incident surface 101 a of the light guide 101. The light emitting element 110 includes a package 108, a concave mirror 109, and a light source 103. The concave mirror 109 is provided in the concave portion 108 a of the package 108. The shape of the concave mirror 109 is a curved surface shape following the shape of the concave portion 108 a of the package 108. The concave mirror 109 is a parabolic mirror having a vertex Pc at the position farthest from the light source 103.

  The reflection surface 109a of the concave mirror 109 has its vertex when the reflection surface 109a is cut by two planes perpendicular to each other including the central axis CL of the concave mirror 109 (the optical axis of the light reflected by the reflection surface 109a). It is an anamorphic reflecting surface in which the curvature of the cross section in Pc is different from each other. Assuming that two directions orthogonal to each other in a plane perpendicular to the optical axis CL of the light reflected by the reflecting surface 109a are a first direction and a second direction, the light in the first direction and the second direction Are different from each other. The direction in which the light diffusion angle is large is the direction (y direction) perpendicular to the normal line of the light exit surface 101b of the light guide 101 and perpendicular to the light propagation direction. This is a direction (z direction) parallel to the normal line of the light exit surface 101b of the light body 101.

  In the present embodiment, the shape of the cross section 109B parallel to the xz plane of the reflective surface 109a is a parabola, and the shape of the cross section 109A parallel to the xy plane of the reflective surface 109a is a straight line. The curvature of the cross section 109A is 0, and the curvature of the cross section 109B is greater than zero. The light source 103 is arranged at the focal point of the parabola in the cross section 109B of the reflecting surface 109a. Therefore, the angular distribution of the light reflected by the reflecting surface 109a has a small spread in the z direction and a large spread in the y direction. Since the spread of light in the z direction is smaller than the spread of light in the y direction, the diffusion angle in the z direction is smaller than the diffusion angle in the y direction.

  FIG. 6 is a diagram showing a light amount distribution inside the light guide. In FIG. 6, the upper side is a plan view of the light guide 101 and the light emitting element 110 viewed from the z direction, and the lower side shows the light amount distribution inside the light guide in the AA ′ cross section of the light guide 101. FIG.

  The curvature of the cross section 109A of the reflecting surface 109a is zero. Therefore, the reflecting surface 109a has no light collecting action with respect to the spread of light in the y direction. Therefore, the light emitted from the light emitting element 110 spreads to the boundary portion between the adjacent light emitting elements 102, and the amount of light at the boundary portion increases. Therefore, the light quantity distribution in the AA ′ cross section of the light guide 101 is made uniform. Therefore, the backlight 111 with less luminance unevenness can be obtained.

[Third Embodiment]
FIG. 7 is an enlarged view of the light emitting element 114 provided in the backlight according to the third embodiment.

  The light emitting element 114 is different from the light emitting element 102 of the first embodiment in that a plurality of light sources 103 are integrally attached to a long-axis package 112 having a length corresponding to a plurality of light emitting elements. Constituent elements common to the light emitting element 102 of the first embodiment in the light emitting element 114 are denoted by the same reference numerals, and detailed description thereof is omitted.

  A plurality of recesses 112a corresponding to each light source 103 is formed in the package 112 along the y direction. Concave mirrors 113 are formed in the plurality of recesses 112a. The shape of the concave mirror 113 is a curved surface shape following the shape of the concave portion 112a of the package 112. The concave mirror 113 is a parabolic mirror that reflects the light emitted from the light source 103. The shape of the recess 112a is formed, for example, by pressing a mold having a convex shape obtained by inverting the shape of the recess 112a on the surface of the resin member to be the package 112. The shape of the recess 112a may be formed by cutting the surface of a flat resin member.

  The concave mirror 113 is a parabolic mirror whose apex Pc is the position farthest from the light source 103. The reflection surface 113a of the concave mirror 113 has its vertex when the reflection surface 113a is cut by two planes orthogonal to each other including the central axis CL of the concave mirror 113 (the optical axis of the light reflected by the reflection surface 113a). It is an anamorphic reflecting surface in which the curvature of the cross section in Pc is different from each other.

  In the case of the present embodiment, the shapes of the cross-section 113B parallel to the xz plane and the cross-section 113A parallel to the xy plane of the reflecting surface 113a are both parabolas. The curvature of the parabola in the cross section 113B parallel to the xz plane of the reflection surface 113a is larger than the curvature of the parabola in the cross section 113A parallel to the xy plane of the reflection surface 113a. The light source 103 is disposed at the focal point of the parabola in the cross section 113B parallel to the xz plane of the reflection surface 113a. Therefore, the angular distribution of the light reflected by the reflecting surface 113a has a small spread in the z direction and a large spread in the y direction. Since the spread of light in the z direction is smaller than the spread of light in the y direction, the diffusion angle in the z direction is smaller than the diffusion angle in the y direction.

  In the light emitting device 114 of this embodiment, a plurality of light sources 103 are packaged in the same package. Therefore, the number of parts is reduced, and the light emitting element 114 can be easily attached to the light guide.

[Fourth Embodiment]
FIG. 8 is an exploded perspective view of a liquid crystal display device (display device) 1 including the backlight (light control element) 3 according to the fourth embodiment.

  As shown in FIG. 8, the liquid crystal display device 1 includes a liquid crystal panel 2 (display element) and a backlight 3 disposed on the back side of the liquid crystal panel 2.

  The liquid crystal panel 2 is a transmissive liquid crystal panel that performs display using light emitted from the backlight 3. The user can view the display from the opposite side of the backlight 3, that is, from the upper side of the liquid crystal panel 2 in FIG. The configuration of the liquid crystal panel 2 is not particularly limited, and may be an active matrix liquid crystal panel provided with a switching thin film transistor (hereinafter abbreviated as TFT) for each pixel, or provided with a TFT. It may be a simple matrix type liquid crystal panel. In addition, the liquid crystal panel is not limited to a transmissive liquid crystal panel, and may be a transflective liquid crystal panel. The display mode is not particularly limited, and various display modes such as VA (Vertical Alignment) mode, TN (Twisted Nematic) mode, STN (Super Twisted Nematic) mode, and IPS (In-Plane Switching) mode are available. A liquid crystal panel can be used.

  The backlight 3 includes three backlight units 4 having the same dimensions, shape, and configuration. The three backlight units 4 are in a direction orthogonal to the longitudinal direction of the light guide 5, that is, in a direction (y direction) orthogonal to the direction in which the three light extraction regions RA, RB, RC of the light guide 5 are arranged. It is arranged adjacent to each other. Therefore, the backlight 3 has a total of nine light extraction regions RA, RB, RC, three in each of the horizontal and vertical directions on the screen of the liquid crystal display device 1.

  Each backlight unit 4 includes an illumination unit 6 and a light guide 5. The illumination unit 6 includes a plurality of (three in the example of FIG. 8) light emitting elements 7a, 7b, and 7c.

  The light emitting elements 7a, 7b, and 7c are light emitting elements having the configuration shown in the first embodiment or the second embodiment. That is, when two directions orthogonal to each other in a plane perpendicular to the optical axis of light emitted from the light emitting surface of the light emitting element are defined as the first direction and the second direction, the first direction and The light emitting elements have different diffusion angles of light in the second direction. The direction in which the light diffusion angle is large is a direction (y direction) orthogonal to the normal line of the main surface 5a of the light guide 5 and orthogonal to the light propagation direction, and the direction in which the light diffusion angle is small is the light guide. It is a direction (z direction) parallel to the normal line of the main surface 5a of the body 5. The main surface 5 a of the light guide 5 is a light emission surface from which light propagated through the light guide 5 is emitted toward the liquid crystal panel 2.

  The light guide 5 is composed of a parallel plate made of a resin having optical transparency such as acrylic resin. In the example of FIG. 8, the backlight 3 is composed of three backlight units 4 with separate light guides, but has a total of nine light extraction regions RA, RB, RC. The body may have an integral structure. Even with this structure, it is possible to select the light extraction regions RA, RB, and RC for emitting light by using a light emitting element with high directivity.

  Three light emitting elements 7 a, 7 b, 7 c are installed on one end face of the light guide 5 with the light emission side facing the light guide 5. The light guide 5 receives light emitted from the light emitting elements 7a, 7b, and 7c, totally reflects the light internally, and is opposite to the end face side where the light emitting elements 7a, 7b, and 7c are installed. It has a function of propagating toward the end face (from the −x direction to the + x direction in FIG. 8) and taking it out to the external space. Further, the three light emitting elements 7a, 7b, and 7c can be individually controlled to be turned on / off, and the amount of emitted light can be controlled. Thereby, the backlight 3 functions as a light control element which can adjust the light quantity of the light inject | emitted.

  Although not shown, the backlight 3 includes a printed wiring board on which the light emitting elements 7a, 7b, and 7c are mounted, a control unit that includes a driving IC for driving and controlling the light emitting elements 7a, 7b, and 7c, and the like. It has been. As the light emitting elements 7a, 7b, and 7c, it is preferable to use light emitting elements having high directivity in the xz plane. For example, the intensity distribution with respect to the spread angle of the emitted light while the light is guided through the light guide 5 is used. Those having a half width (diffusion angle in the xz plane) of about 5 ° can be used.

  Of the two main surfaces of the light guide 5, a plurality of (three in this embodiment) light extraction regions RA, RB, RC are provided on the main surface 5 a facing the liquid crystal panel 2. It is provided along the longitudinal direction (x-axis direction in FIG. 8). In each of the light extraction regions RA, RB, and RC, low refractive index bodies 8a and 8b having a refractive index lower than that of the light guide 5 and a refractive index body having a refractive index equal to the refractive index of the light guide 5 are provided. 9 and the low-refractive-index bodies 8a and 8b and the light scatterer 10 that scatters the light emitted from the refractor 9 are stacked in this order. In the following description, for the sake of convenience, the respective light extraction regions are directed from the side closer to the light emitting elements 7a, 7b, 7c to the side farther from the first light extraction region RA, the second light extraction region RB, and the third light extraction. This is referred to as region RC. In addition, the main surface of the light guide 5 provided with the light extraction regions RA, RB, RC is the first main surface 5a, the main surface opposite to the first main surface 5a is the second main surface 5b, and the light emitting element 7a, The end surface of the light guide 5 provided with 7b and 7c is referred to as a first end surface 5c, and the end surface opposite to the first end surface 5c is referred to as a second end surface 5d.

  The low refractive index bodies 8 a and 8 b both have a refractive index lower than the refractive index of the light guide 5, and the refractive index body 9 has a refractive index equal to the refractive index of the light guide 5. The low refractive index bodies 8a and 8b and the refractive index body 9 have different refractive indexes. Further, the low refractive index bodies 8a and 8b and the refractive index body 9 are arranged along the propagation direction of light emitted from the light emitting elements 7a, 7b and 7c and incident on the light extraction regions RA, RB and RC (FIG. 8 from the −x direction to the + x direction) in the order of relatively low refractive index to relatively high refractive index. For example, the refractive index nWG of the light guide 5 is 1.5, the refractive index nA of the first low refractive index body 8a provided in the first light extraction region RA is 1.3, and the second light extraction The refractive index nB of the second low refractive index body 8b provided in the region RB is 1.4, and the refractive index nC of the refractive index body 9 provided in the third light extraction region RC is 1.5.

  As a method of forming the low refractive index bodies 8a and 8b and the refractive index body 9 having different refractive indexes, for example, the following two methods can be cited.

The first method is to form the low refractive index bodies 8a and 8b and the refractive index body 9 using different materials. For example, an acrylic resin is used as a material of the light guide 5, and an amorphous fluororesin “AF1600” (registered trademark, refractive index: n _A = 1.29 to 1) manufactured by DuPont is used as a material of the first low refractive index body 8 a. .31), UV curing resin “OP40” (registered trademark, refractive index: n _B = 1.403) manufactured by DIC as the material of the second low refractive index body 8b, and Kuraray Co., Ltd. as the material of the refractive index body 9. Each liquid material of methacrylic resin “parapet (optical grade)” (registered trademark, refractive index: n _C = 1.49) is selectively applied onto the light guide 5 and cured.

  Since the refractive index body 9 has the same refractive index as that of the light guide 5, it is not always necessary to form the refractive index body 9 on the light guide 5. For example, the light scatterer 10 may be merely disposed on the light guide 5.

The second technique is to use a material containing a low refractive index material in a predetermined substrate and adjust the refractive index by varying the concentration of the low refractive index material. For example, in the methacrylic resin “Parapet (Optical Grade)” (registered trademark, refractive index: n _C = 1.49) manufactured by Kuraray Co., Ltd. used as the material of the refractive index body 9, the mesoporous silica nanometer manufactured by Ardrich is used. Low refractive index materials such as powder (registered trademark, refractive index: 1.27) or airgel (registered trademark, refractive index: 1.27) manufactured by Jason Wells are included, and the concentration of these low refractive index materials is different. Two types of liquids are prepared. Each liquid material can be selectively applied on the light guide 5 and cured.

  A light scatterer 10 is laminated on the low refractive index bodies 8 a and 8 b and the refractive index body 9. The light scatterer 10 has a function of scattering the light incident from the low refractive index bodies 8 a and 8 b and the refractive index body 9 and extracting the light to the external space of the backlight 3. Specifically, as the light scatterer 10, a commercially available light scattering film in which scattering beads or the like are coated on the base film can be used, and the light is scattered on the low refractive index bodies 8 a and 8 b and the refractive index body 9. The light scatterer 10 can be formed by sticking a scattering film. As the light scatterer 10 of this embodiment, it is desirable to use a light scattering film with high light scattering ability.

  In each backlight unit 4, the first end surface 5 c of the light guide 5 is divided into three in the short direction of the light guide 5 (y direction in FIG. 8), and the angles with respect to the first main surface 5 a are different from each other 3. Two inclined surfaces 11a, 11b, and 11c are formed. For these inclined surfaces 11a, 11b, and 11c, for example, a light guide whose angle between the first main surface 5a and the end surface is a right angle is prepared, and the end surface is divided into three regions divided into three regions. It can be formed by a method such as grinding at an angle so as to form a different angle with respect to one principal surface 5a. And one light emitting element 7a, 7b, 7c is being fixed to the approximate center of each inclined surface 11a, 11b, 11c via the optical adhesive agent one by one. Therefore, three light emitting elements 7 a, 7 b, 7 c are arranged in the short direction of the light guide 5 over the entire first end face 5 c.

  In the following description, for convenience, among the three inclined surfaces 11a, 11b, and 11c of the first end surface 5c, the inclined surface (right side in FIG. 8) having the smallest angle with respect to the first main surface 5a is defined as the first light incident surface. 11a, the inclined surface (center of FIG. 8) having the next smallest angle with respect to the first main surface 5a is the second light incident surface 11b, and the inclined surface (left side of FIG. 8) having the largest angle with respect to the first main surface 5a is third. This is referred to as a light incident surface 11c. Further, the light emitting element provided on the first light incident surface 11a is provided on the first light emitting element 7a, and the light emitting element provided on the second light incident surface 11b is provided on the second light emitting element 7b and the third light incident surface 11c. The light emitting element is referred to as a third light emitting element 7c.

  9A is a cross-sectional view taken along line AA ′ in FIG. 8, FIG. 9B is a cross-sectional view taken along line BB ′ in FIG. 8, and FIG. 9C is a cross-sectional view taken along line CC in FIG. It is sectional drawing which follows a line.

In the case of the present embodiment, the angle β _A formed by the first light incident surface 11a and the first main surface 5a is 55 °, the angle β _B formed by the second light incident surface 11b and the first main surface 5a is 65 °, The angle β _C formed by the third light incident surface 11c and the first main surface 5a is set to 75 °. The light emitting elements 7a, 7b, and 7c are fixed so that the light La, Lb, and Lc enter perpendicularly to the light incident surfaces 11a, 11b, and 11c, and are emitted from the light emitting elements 7a, 7b, and 7c. The light La, Lb, and Lc propagates from the first end surface 5c side to the second end surface 5d side while repeating total reflection between the first main surface 5a and the second main surface 5b of the light guide 5. Is done.

Here, if the angle formed by the optical axis with respect to the virtual horizontal plane passing through the center of the light guide 5 in the thickness direction is defined as the propagation angle φ, the propagation angle φ _A of the light La from the first light emitting element 7a is 35 °, 2 propagation angle phi _B light Lb from the light emitting element 7b is 25 °, the propagation angle phi _C of the light Lc from the third light-emitting element 7c is 15 °. Therefore, while each light La, Lb, Lc is propagated from the first end face 5c side toward the second end face 5d side, the first light extraction area RA, the second light extraction area RB, and the third light extraction area RC. In this order, the light enters the light extraction areas RA, RB, RC.

  9A to 9C, the thickness (dimension in the z direction) is drawn sufficiently larger than the longitudinal dimension (dimension in the x direction) of the light guide 5 in order to make the drawings easy to see. Since only the central axis of the light emitted from each light emitting element 7a, 7b, 7c is drawn, it seems that light may not necessarily enter each light extraction area RA, RB, RC. Since the thickness of the light guide 5 is sufficiently small relative to the longitudinal dimension of the light guide 5 and the light La, Lb, Lc from the light emitting elements 7a, 7b, 7c has a finite light beam diameter, the light La , Lb, Lc are reliably incident on the light extraction regions RA, RB, RC.

That is, the illuminating unit 6 of the present embodiment includes three light emitting elements 7a, 7b, and 7c. Lights La, Lb, and Lc from the light emitting elements 7a, 7b, and 7c are converted into the light extraction regions RA, Lights La, Lb, and Lc are extracted from RB and RC and are incident on the light extraction regions RA, RB, and RC at an incident angle including an incident angle at which the light can be extracted. In addition, the illumination unit 6 is incident on one light extraction area RA, RB, RC at three different incident angles θ (θ _A = 55 °, θ _B = 65 °, θ _C = 75 °). Then, by switching which light emitting element 7a, 7b, 7c is lit, the light propagation angle φ (φ _A = 35 °, φ _B = 25 °, φ _C = 15 ° inside the light guide 5 ) Switching function.

  Here, the light La, Lb, and Lc from each light emitting element 7a, 7b, and 7c are the light guide 5 in each light extraction area | region RA, RB, RC, each low refractive index body 8a, 8b, and the refractive index body 9, Consider the critical angle when entering the interface.

The interface between the light guide 5 and the first low refractive index body in the first light extraction region RA is the first low refraction with the refractive index n _WG = 1.5 and the refractive index n _A = 1.3. Since it becomes an interface with the rate body 8a, the critical angle γ _A is 60.1 ° according to Snell's law. Therefore, in the first light extraction region RA, light incident at an incident angle of less than 60.1 ° is transmitted through the interface, and light incident at an incident angle of 60.1 ° or more is totally reflected at the interface. Similarly, the interface between the light guide 5 and the second low refractive index body 8b in the second light extraction region RB is the light guide 5 having a refractive index n _WG = 1.5 and a refractive index n _B = 1.4. Therefore, the critical angle γ _B is 69.0 °. Therefore, in the second light extraction region RB, light incident at an incident angle of less than 69.0 ° is transmitted through the interface, and light incident at an incident angle of 69.0 ° or greater is totally reflected at the interface. On the other hand, the interface between the light guide 5 and the refractive index body 9 in the third light extraction region RC is a refraction having a refractive index n _WG = 1.5 and a refractive index n _C = 1.5. Since it becomes an interface with the index body 9, light passes through the interface at all incident angles.

  That is, when the first light extraction area RA, the second light extraction area RB, and the third light extraction area RC are viewed independently, the incident angle range in which light can be extracted outside in the first light extraction area RA is 60. Less than 1 °, the incident angle range in which light can be extracted outside in the second light extraction region RB is less than 69.0 °, and the incident angle range in which light can be extracted outside in the third light extraction region RC is all angles. It becomes a range.

  As described above, the two low refractive index bodies 8a and 8b and the refractive index body 9 provided in the three light extraction regions RA, RB, and RC of the present embodiment are incident on the light extraction regions RA, RB, and RC. Along the light propagation direction, the light is arranged in the order of relatively low refractive index to relatively high refractive index. Based on such a difference in refractive index, the three light extraction regions RA, RB, and RC have different incident angle ranges in which light can be extracted to the outside. Further, the three light extraction areas RA, RB, and RC have a relatively narrow incident angle range that can be extracted from a light extraction area that has a relatively narrow incident angle range along the propagation direction of incident light. Wide light extraction region (incident angle range that can be extracted in the first light extraction region RA is less than 60.1 °, incident angle range that can be extracted in the second light extraction region RB is less than 69.0 °, third light The range of incident angles that can be extracted in the extraction region RC is arranged in the order of all angle ranges).

At this time, as shown in FIG. 9A, assuming that the first light emitting element 7a fixed to the first light incident surface 11a is turned on, the angle formed by the first light incident surface 11a and the first main surface 5a. Since β _A is 55 ° and the light La from the first light emitting element 7a is perpendicularly incident on the first light incident surface 11a, the light La from the first light emitting element 7a is incident on the first main surface 5a. The angle θ _A is 55 °. In addition, since the light guide 5 of the present embodiment is configured by parallel plates, the incident angle θ _{A with} respect to the first major surface 5a is no matter how many times the light La from the first light emitting element 7a repeats total reflection. Always 55 °. When the light La from the first light emitting element 7a reaches the first light extraction region RA and enters the interface between the light guide 5 and the first low refractive index body 8a at an incident angle θ _A = 55 °, Since the critical angle γ _{A at 6} is 60.1 °, the light La passes through the interface between the light guide 5 and the first low refractive index body 8a and is incident on the first low refractive index body 8a. It is scattered by the light scatterer 10 and taken out to the outside. In this way, substantially the entire amount of the light La emitted from the first light emitting element 7a can be extracted from the first light extraction region RA.

Next, as shown in FIG. 9B, when the first light emitting element 7a is turned off and the second light emitting element 7b fixed to the second light incident surface 11b is turned on, the second light incident surface 11b The angle β _B formed with the first main surface 5a is 65 °, and the light Lb from the second light emitting element 7b is perpendicularly incident on the second light incident surface 11b, and therefore the light from the second light emitting element 7b. The incident angle θ _B of Lb with respect to the first major surface 5a is 65 °. When the light Lb from the second light emitting element 7b reaches the first light extraction region RA and enters the interface between the light guide 5 and the first low refractive index body 8a at an incident angle θ _B = 65 °, since the critical angle gamma _a is 60.1 ° in the light Lb can not transmit the interface of the light guide 5 and the first low refractive index member 8a, totally reflected. Next, the light Lb from the second light emitting element 7b reaches the second light extraction region RB, and is incident at an incident angle θ _B = 65 ° with respect to the interface between the light guide 5 and the second low refractive index body 8b. Then, since the critical angle γ _B here is 69.0 °, the light Lb passes through the interface between the light guide 5 and the second low refractive index body 8b and is incident on the second low refractive index body 8b. Then, it is taken out from the light scatterer 10 to the outside. In this way, substantially the entire amount of the light Lb emitted from the second light emitting element 7b can be extracted from the second light extraction region RB.

  If the light La emitted from the first light emitting element 7a is incident on the second light extraction region RB, this condition also satisfies the condition that the incident angle is smaller than the critical angle. It can be taken out from the region RB. However, almost all of the light La emitted from the first light emitting element 7a is extracted in the first light extraction area RA before reaching the second light extraction area RB, and thus almost reaches the second light extraction area RB. There is nothing to do. Therefore, actually, the light La emitted from the first light emitting element 7a is not extracted from the second light extraction region RB, and the light Lb emitted from the second light emitting element 7b is extracted from the second light extraction region RB. Will be. Based on such a principle, the backlight 3 of the present embodiment can extract light emitted from a predetermined light emitting element only from a predetermined light extraction region.

Next, as shown in FIG. 9C, when the second light emitting element 7b is turned off and the third light emitting element 7c fixed to the third light incident surface 11c is turned on, the third light incident surface 11c The angle β _C formed with the first main surface 5a is 75 °, and the light Lc from the third light emitting element 7c is perpendicularly incident on the second light incident surface 11c. Therefore, the light from the third light emitting element 7c The incident angle θ _C of Lc with respect to the first major surface 5a is 75 °. The light Lc from the second light emitting element 7c reaches the first light extraction area RA or the second light extraction area RB, and the interface between the light guide 5 and the first low refractive index body 8a or the second low refractive index body 8b. Is incident at an incident angle θ _C = 75 °, the incident angle θ _C is larger than the critical angle γ _A and the critical angle γ _B , so that the light Lc cannot be transmitted through each interface and is totally reflected. Thereafter, when the light Lc from the third light emitting element 7c reaches the third light extraction region RC, the light Lc passes through the interface between the light guide 5 and the refractive index body 9 and is incident on the refractive index body 9, and thereafter , Extracted from the light scatterer 10 to the outside. In this way, substantially the entire amount of the light Lc emitted from the third light emitting element 7c can be extracted from the third light extraction region RC.

  FIG. 10A to FIG. 10C are diagrams showing light diffusion angles DA, DB, and DC in the y direction of the first light emitting element 7a, the second light emitting element 7b, and the third light emitting element 7c.

  The first light emitting element 7a, the second light emitting element 7b, and the third light emitting element 7c have different y-direction light diffusion angles DA, DB, and DC (light spread in the y direction). The light diffusion element in which light is extracted from the light extraction region close to the first end face 5c has a larger light diffusion angle in the y direction.

  In the example of FIG. 10, the light diffusion angle DA in the y direction of the first light emitting element 7a from which light is extracted from the first light extraction region RA closest to the first end face 5c is the largest. The second light emitting element 7b from which light is extracted from the second light extraction region RB next to the first end surface 5c next to the first light extraction region RA has the second largest light diffusion angle DB in the y direction. The light diffusion angle DC in the y direction of the third light emitting element 7c from which light is extracted from the third light extraction region RC farthest from the first end face 5c is the smallest.

  The distance from the first end face 5c to the first light extraction area RA is LA, the distance from the first end face 5c to the second light extraction area RB is LB, and the distance from the first end face 5c to the third light extraction area RC is LC. , The width of the light guide 5 in the y direction is W, the diffusion angle of light in the y direction of the first light emitting element 7a is DA, the diffusion angle of light in the y direction of the second light emitting element 7b is DB, and the third light emitting element 7c. If the diffusion angle of light in the y direction is DC, the diffusion angles DA, DB, DC satisfy the following equations.

  As shown in FIG. 10A, the light emitted from the first light emitting element 7a propagates in the x direction inside the light guide 5 while spreading in the y direction. When the light emitted from the first light emitting element 7a reaches the first light extraction region RA, the light spreads to a position separated by W / 2 or more in the + y direction and the −y direction. Therefore, the lights emitted from the adjacent first light emitting elements 7a overlap with each other, and a uniform amount of light can be obtained in the entire first light extraction region RA.

  As shown in FIG. 10B, the light emitted from the second light emitting element 7b propagates in the x direction inside the light guide 5 while spreading in the y direction. The light emitted from the second light emitting element 7b spreads to a position separated by W / 2 or more in the y direction when it reaches the second light extraction region RB. Therefore, the lights emitted from the adjacent second light emitting elements 7b overlap with each other, and a uniform amount of light can be obtained in the entire second light extraction region RB.

  As shown in FIG. 10C, the light emitted from the third light emitting element 7c propagates in the x direction inside the light guide 5 while spreading in the y direction. When the light emitted from the third light emitting element 7c reaches the third light extraction region RC, the light spreads to a position separated by W / 2 or more in the + y direction and the −y direction. Therefore, the lights emitted from the adjacent third light emitting elements 7c overlap each other, and a uniform amount of light can be obtained in the entire third light extraction region RC.

  According to the backlight 3 of the present embodiment, the three light extraction regions RA, RB, RC depend on which one of the three light emitting elements 7a, 7b, 7c of each backlight unit 4 is turned on. It is possible to select as appropriate from which light extraction region of the light extraction region, that is, which light extraction region RA, RB, RC emits light. Further, by controlling the amount of light emitted from each light emitting element 7a, 7b, 7c, the amount of light extracted from the selected light extraction regions RA, RB, RC, that is, the brightness of the selected light extraction region. Can be adjusted.

  The backlight 3 of this embodiment can control whether or not light is emitted from each of the light extraction regions RA, RB, and RC simply by switching the light emitting elements 7a, 7b, and 7c to be turned on. Therefore, by efficiently taking out the light emitted from the illumination unit 6 from the light guide 5, a sufficient amount of light can be obtained and a backlight with high contrast can be realized. Furthermore, the structure can be simplified, the thickness can be reduced, and the inexpensive backlight 3 can be realized. In addition, by using the backlight 3 described above, it is possible to realize the liquid crystal display device 1 that can display brightly and with high contrast.

[Configuration example of display device]
Hereinafter, one configuration example of the display device will be described with reference to FIGS.
FIG. 11 is an exploded perspective view showing a schematic configuration of a liquid crystal display device which is a configuration example of the display device. 12A, 12B, 13A, and 13B are diagrams illustrating examples of backlight arrangement in a liquid crystal display device.

  As shown in FIG. 11, the liquid crystal display device 121 of this configuration example includes a lower case 122, a reflection plate 123, a backlight 3 (light control element), a diffusion plate 124, and a liquid crystal panel 2 (display element). And an upper case 125. That is, a laminated body of the reflecting plate 123, the backlight 3, the diffusion plate 124, and the liquid crystal panel 2 is accommodated in the lower case 122 and the upper case 125. By disposing the reflector 123 on the opposite side of the backlight 3 from the liquid crystal panel 2, light leaking from the backlight 3 to the opposite side of the liquid crystal panel 2 can be reflected and contributed to display. Further, by disposing the diffusion plate 124 between the backlight 3 and the liquid crystal panel 2, luminance unevenness of the backlight 3 can be reduced. However, the reflecting plate 123 and the diffusing plate 124 are not necessarily used.

  As shown in FIG. 12A, a configuration is adopted in which a plurality of backlights 3 are arranged so that the light extraction areas RA, RB, RC are arranged in the vertical direction of the screen in the screen of the liquid crystal display device 121. be able to. Alternatively, as shown in FIG. 12B, in the screen of the liquid crystal display device 127, a configuration in which a plurality of backlights 3 are arranged so that the light extraction areas RA, RB, RC are arranged in the horizontal direction of the screen. Can be adopted.

  Alternatively, as shown in FIGS. 13A and 13B, light extraction regions RA, RB, RC are provided only in a part in the longitudinal direction, and the other parts are elongated rods that are regions where light is guided. A backlight 137 in which a plurality of light guides 135 (three in this example) are combined may be used. In the plurality of light guides 135, regions where the light extraction regions RA, RB, RC are provided are shifted in the longitudinal direction. Therefore, when a plurality of light guides 135 are combined, the light extraction regions RA, RB, and RC are arranged along the longitudinal direction of the light guide 135.

  For example, as shown in FIG. 13A, in the screen of the liquid crystal display device 131, a plurality of backlights 137 are arranged so that the light extraction areas RA, RB, RC are aligned in the vertical direction of the screen. Also good. Alternatively, as shown in FIG. 13B, in the screen of the liquid crystal display device 133, a plurality of backlights 137 are arranged so that the light extraction areas RA, RB, RC are aligned in the horizontal direction of the screen. Also good.

[Configuration example of lighting device]
Hereinafter, two configuration examples of the lighting device will be described with reference to FIGS. 14 and 15.
FIG. 14 is a cross-sectional view of the illumination device that is the first configuration example. FIGS. 15A and 15B are diagrams illustrating a lighting device which is a second configuration example, in which FIG. 15A is a plan view and FIG. 15B is an A- in FIG. 15A. It is sectional drawing which follows an A 'line.

  For example, in the illumination device 201 shown in FIG. 14, the first low refractive index body 8 a having a refractive index of 1.3 is formed on the first main surface 5 a side of the light guide 5, and the refractive index is on the second main surface 5 a side. A second low refractive index body 8b of 1.4 is formed. A light scatterer 10 is stacked on the first low refractive index body 8a and the second low refractive index body 8b. Other configurations are the same as those of the first embodiment. In FIG. 14, only one first end face 5c is shown, but actually, another one first end face having a different angle with respect to the first main face 5a is formed in the depth direction of the paper. As for the light emitting element, only one light emitting element 7a is shown, but actually, another one light emitting element is installed in the depth direction of the drawing.

  In the illumination device 201, the light emitting element 201 emits light from the first main surface 5a side depending on which one of the two light emitting elements provided on the first end surface 5c of the light guide 5 is lit. It is possible to switch whether light is emitted from the two principal surfaces 5b side. Therefore, it is possible to realize an illumination device that can switch the light emitting surface.

  Further, in the lighting device 203 illustrated in FIG. 15A, a character portion 204 on which “SHARP” is written is formed on one surface of the light guide 5. Corresponding to the character portion 204, as shown in FIG. 15B, a first low refractive index body 8a having a refractive index of 1.3 is formed on the first main surface 5a side of the light guide 5; The first low refractive index body 8a is not formed in a portion other than the character portion 204. A light scatterer 10 is stacked on the first low refractive index body 8a. That is, the character part 204 is a light extraction area in the above embodiment. Other configurations are the same as those of the first embodiment. In FIG. 15B, only one first end face 5c is shown, but in actuality, another one first end face having a different angle with respect to the first main face 5a is formed in the depth direction of the paper. . As for the light emitting element, only one light emitting element 7a is shown, but actually, another one light emitting element is installed in the depth direction of the drawing.

  In the lighting device 203, light is emitted from the character part 204 depending on which of the two light emitting elements provided on the first end surface 5 c of the light guide 5 is lit, or other than the character part 204. It is possible to switch whether light is emitted from Therefore, according to this structure, the illuminating device which can be utilized as digital signage which can blink the character part 204, for example is realizable.

  The present invention can be used for a light emitting element, a light control element, a display device, and a lighting device.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device (display apparatus), 2 ... Liquid crystal panel (display element), 3 ... Backlight, 5 ... Light guide, 7a, 7b, 7c ... Light emitting element, 8a, 8b ... Low refractive index body, 9 ... Refractive index body, 11a, 11b, 11c ... light incident surface, 100 ... back light (dimming element), 101 ... light guide, 101a ... light incident surface, 101b ... light emitting surface, 102 ... light emitting element, 103 ... light source 104 ... package, 104a ... concave, 105 ... concave mirror, 105a ... reflective surface, 105A, 105B ... cross section of concave mirror, 107 ... light transmitting member, 108 ... package, 108a ... concave, 109 ... concave mirror, 109a ... reflective , 109A, 109B ... cross section of concave mirror, 110 ... light emitting element, 111 ... backlight (dimming element), 112 ... package, 112a ... concave, 113 ... concave mirror, 11 a ... reflecting surface, 113A, 113B ... cross section of concave mirror, 121,127,131,133 ... liquid crystal display device (display device), 135 ... light guide, 137 ... backlight (dimming element), 201,203 ... Illumination device, CL: central axis of concave mirror (optical axis of light reflected by reflecting surface), D1, D2, DA, DB, DC: diffusion angle, Pf: parabolic focus, RA, RB, RC: light extraction region

Claims (13)

A light source;
A reflective surface for reflecting the light emitted from the light source,
When the two directions perpendicular to each other in a plane perpendicular to the optical axis of the light reflected by the reflecting surface are defined as the first direction and the second direction, the light diffusion angle in the first direction And a light emitting element having different diffusion angles of light in the second direction.   The reflection surface is an anamorphic reflection surface having different curvatures of cross sections of the reflection surface at points on the optical axis when the reflection surface is cut by two orthogonal planes including the optical axis. The light emitting device according to claim 1. The shape of the reflecting surface in a cross section having a large curvature among the two cross sections is a parabola,
The light emitting element according to claim 2, wherein the light source is disposed at a focal point of the parabola.   4. The light-emitting element according to claim 2, wherein a curvature of the reflecting surface in a section having a small curvature among the two sections is 0. 5. A package having a recess formed therein;
The reflective surface is formed in the recess of the package;
The concave portion is filled with a light transmissive member that transmits light emitted from the light source,
The light emitting element according to claim 2, wherein the light source is embedded in the light transmitting member. A plurality of the light sources are arranged in one direction,
The light emitting device according to claim 5, wherein the reflection surface corresponding to each light source is provided in the package along an arrangement direction of the plurality of light sources. A light guide having a light incident surface and a light exit surface;
A plurality of light emitting elements that allow light to enter the light incident surface of the light guide,
The light guide is provided with a plurality of light extraction regions along the propagation direction of the light from which light propagated inside the light guide can be extracted to the outside of the light guide.
The propagation angles of light that can be extracted from the plurality of light extraction regions are different from each other,
Light emitted from the plurality of light emitting elements propagates through the light guide at different propagation angles,
The plurality of light emitting elements are the light emitting elements according to any one of claims 1 to 6,
In the light-emitting element, the direction in which the light diffusion angle is large is a direction perpendicular to the normal line of the light exit surface of the light guide and the light propagation direction, and the direction in which the light diffusion angle is small is The light control element which is a direction parallel to the normal line of the light-projection surface of the said light guide.   The light control element according to claim 7, wherein in the plurality of light extraction regions, refractive indexes of members that are in contact with the light exit surface of the light guide are different from each other.   The light control element according to claim 8, wherein the refractive index of the member in contact with the light emitting surface of the light guide is larger as the refractive index is arranged farther from the light incident surface of the light guide. The light incident surface of the light guide is provided with a plurality of inclined surfaces having different angles with the light exit surface of the light guide,
The light control device according to claim 9, wherein each of the plurality of light emitting devices is fixed to each of the plurality of inclined surfaces.   Light in a direction orthogonal to the normal line of the light emitting surface of the light emitting element that emits light extracted from the light extraction region at a position relatively close to the light incident surface and orthogonal to the propagation direction of the light The diffusion angle of the light emitting element is orthogonal to the normal line of the light emitting surface of the light emitting element that emits light extracted from the light extraction region at a position relatively far from the light incident surface, and the light propagation direction. The light control element according to claim 10, wherein the light control element is larger than a light diffusion angle in a direction orthogonal to each other.   A display device comprising: the light control device according to claim 7; and a display device that performs display using light emitted from the light control device.   The illuminating device provided with the light control element of any one of Claims 7 thru | or 11.

Images