Liquid crystal display, lighting device, and optical device

Abstract

To provide an optical device, a lighting device, and a liquid crystal display in which emission light is substantially uniform in all directions.SOLUTION: An optical device 1 is a transparent plate-like optical device 1 having a front surface, a back surface, and a plurality of end surfaces 11, and has a pyramidal structure 2 on at least one of the front surface and back surface, where the pyramidal structure 2 has a ridge line 23 in a direction perpendicular to at least one of the front, back, left, and right end surfaces. A lighting device 100 comprises a light source 3 and the optical device 1, and at least a part of light L1 from the light source 3 is transmitted through the pyramidal structure 2. A liquid crystal display device 300 has the lighting device 100.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present invention relates to a liquid crystal display device, a lighting device, and an optical device. [Background technology]

[0002] Conventionally, liquid crystal display devices equipped with a side-edge type backlight system having a light guide plate have been widely put to practical use for televisions, PC monitors, smartphones, etc. A liquid crystal display device that reproduces the optical characteristics of a print display medium and gives the user the feeling that the display medium is a print medium such as paper has been proposed in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-86457 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order for a liquid crystal display device to give the impression of being a print medium such as paper, it is required that the light emitted from the liquid crystal display device is approximately uniform in all directions like reflected light. In a liquid crystal display device, the transmittance of the liquid crystal layer is not uniform in all directions. For this reason, a lighting device that has light distribution characteristics that compensate for the non-uniformity of the transmittance of the liquid crystal layer and functions as a backlight is required.

[0005] An object of the present invention is to provide an optical device, an illumination device, and a liquid crystal display device from which emitted light is substantially uniform in all directions. [Means for solving the problem]

[0006] (1) The optical device is a transparent, plate-like optical device having a front surface, a back surface, and multiple end surfaces, and has a pyramidal structure on at least one of the front surface or back surface, and the pyramidal structure has a ridge line in a direction perpendicular to at least one of the front, back, left, or right end surfaces. (2) The lighting device comprises a light source and the optical device of (1), wherein at least a portion of the light from the light source is transmitted through the cone structure. (3) A liquid crystal display device has the lighting device of (2). Effect of the Invention

[0007] According to the present invention, there are provided an optical device, an illumination device, and a liquid crystal display device in which emitted light is substantially uniform in all directions. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of an overall configuration of a liquid crystal display device according to the present invention. [Figure 2A] FIG. 2 is a perspective view of an optical device according to the present invention, a cone structure, and a side edge light. [Figure 2B] FIG. 1 is a front view of an optical device according to the present invention. [Figure 2C] 1 is a side view of an optical device according to the present invention; [Diagram 3] FIG. 2 is a perspective view showing details of a truncated cone, which is an example of the form of a cone structure according to the present invention. [Figure 4A] FIG. 2 is a perspective view showing details of a quadrangular pyramid, which is an example of the form of a pyramidal structure according to the present invention. [Figure 4B] FIG. 2 is a diagram showing the relationship between the height and edge angle of a cone structure according to the present invention. [Diagram 5] FIG. 2 is a diagram for explaining the definition of the light propagation direction in the side-edge type backlight system according to the present invention. [Figure 6A] FIG. 2 is a perspective view showing a state of light propagation in the optical device according to the present invention. [Figure 6B] 2 is a cross-sectional view showing the propagation state of light in the optical device according to the present invention. FIG. [Figure 6C]2 is a cross-sectional view showing the propagation state of light in the optical device according to the present invention. FIG. [Figure 6D] 1 is a diagram showing the state of light emitted from a cone structure according to the present invention, observed from the front. [Figure 7A] FIG. 2 is a diagram showing the state of light emitted from a cone structure (truncated cone) according to the present invention, observed from the side. [Figure 7B] 1 is a diagram showing the state of light emitted from a cone structure (truncated cone) according to the present invention, observed from the front. [Figure 8] FIG. 1 is a front view of an optical device according to the present invention. [Figure 9] 1 is a perspective view showing a state in which a plurality of pyramidal structures according to the present invention are densely arranged on a surface of an optical device facing a liquid crystal panel. [Figure 10A] FIG. 1 is a cross-sectional view of a side-edge backlight system according to the present invention. [Figure 10B] 4 is a schematic diagram showing the light distribution characteristics of light emitted from a liquid crystal panel according to the present invention. FIG. [Figure 10C] 2 is a schematic diagram showing the light distribution characteristics of light exiting the reverse prism film according to the present invention. FIG. [Figure 10D] 4 is a schematic diagram showing the light distribution characteristic of light emitted from the optical device according to the present invention. FIG. [Figure 11] 5 is a diagram showing the relative intensity of emitted light from a backlight and the relative transmittance of a liquid crystal panel according to the present invention. FIG. [Figure 12] 1 is a perspective view showing a first modified example of the present invention in which a plurality of pyramidal structures, in particular a plurality of concave pyramidal structures, are densely arranged. [Figure 13] FIG. 11 is a perspective view of a cone structure according to Modification 2 of the present invention. [Figure 14A] FIG. 11 is a front view of a cone structure according to a third modified example of the present invention. [Figure 14B] FIG. 11 is a front view of a cone structure according to a third modified example of the present invention. [Figure 15] FIG. 11 is a perspective view of a cone structure according to a fourth modified example of the present invention. [Figure 16A] FIG. 11 is a cross-sectional view of a cone structure according to variant example 5 of the present invention. [Figure 16B]FIG. 13 is a schematic diagram showing the light distribution characteristics of a cone structure according to Modification 5 of the present invention. [Figure 16C] FIG. 11 is a diagram showing the light distribution characteristic of a cone structure according to Modification 5 of the present invention, observed from the light incident direction. [Figure 17A] FIG. 13 is a cross-sectional view of a cone structure according to variant 6 of the present invention. [Figure 17B] FIG. 13 is a front view of a cone structure according to a sixth modified example of the present invention. [Figure 18A] FIG. 13 is a cross-sectional view of a cone structure according to variant 7 of the present invention. [Figure 18B] FIG. 13 is a diagram showing the light distribution characteristic of a cone structure according to Modification 7 of the present invention, observed from the light incident direction. [Figure 19] FIG. 13 is a front view of an optical device according to a ninth modified example of the present invention. [Figure 20] FIG. 23 is a front view of an optical device according to a thirteenth modification of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a liquid crystal display device 300, a lighting device 100, and an optical device 1 according to an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals. When the same components are to be distinguished as a first component and a second component, a, b, etc. are added to the reference numerals.

[0010] As used in this specification, terms that specify shapes, geometric conditions, and the degree thereof, such as "approximately," "parallel," "orthogonal," and "same," as well as values ​​of length and angle, are not to be bound by strict meanings, but are to be interpreted to include a range within which similar functions can be expected.

[0011] Fig. 1 is a cross-sectional view of the overall configuration of a liquid crystal display device 300. The liquid crystal display device 300 includes a liquid crystal panel 200 and an illumination device 100. The illumination device 100 functions as a side-edge type backlight system. The liquid crystal panel 200 includes a pair of polarizing plates 201, a pair of glass substrates 202, a liquid crystal layer 203, a sealant 204, and a driving circuit 205. The illumination device 100 includes a transparent plate-like optical device 1, an optical film 4, a reflective film 5, and a light source 3. In the configuration shown in Fig. 1, the optical device 1 functions as a light guide plate.

[0012] In the following description, the notations X1, X2, Y1, Y2, Z1, Z2, X, Y, and Z are used as appropriate. The X direction is the direction in which light L1 from the light source 3 propagates through the optical device 1. The right direction when the display of the liquid crystal display device 300 is observed from the front is the X1 direction. The X1 direction and the X2 direction are opposite directions to each other. The direction in which the optical device 1 faces the liquid crystal panel 200 is the Z1 direction. The Z2 direction is the opposite direction to the Z1 direction. When the Z1 direction and the Z2 direction are not distinguished, they are referred to as the Z direction. The direction perpendicular to the X direction and the Z direction is the Y direction. The downward direction when the display of the liquid crystal display device 300 is observed from the front is the Y1 direction. The Y2 direction is the opposite direction to the Y1 direction. Only X1 and X2 are shown, and the notation of X may be omitted as appropriate. The same applies to Y and Z. The notations XYZ are given for convenience of explanation and may be interchanged as appropriate.

[0013] 1 may be, for example, an incandescent light bulb, a halogen lamp, a unit in which light emitting diode (LED) light sources are arranged, a hot cathode tube, a cold cathode tube, an inorganic electroluminescence device, an organic electroluminescence device, a laser light device, or the like. The laser light device may be, for example, a laser light scanning and irradiating unit. The light source 3 has one light source 3a and the other light source 3b. The pair of light sources 3 are respectively disposed on a pair of end faces 11 of the optical device 1.

[0014] The optical device 1 is a transparent, plate-like optical device having a front surface 12, a back surface 13, and a plurality of end surfaces 11. As a surface structure, the optical device 1 has a transparent pyramid structure 2 (not shown in FIG. 1 ) on at least one of the front surface 12 or the back surface 13, the details of which will be described later. The pyramid structure 2, the details of which will be described later, includes pyramids, truncated pyramids, and structures in which these are stacked one on top of the other.

[0015] The optical film 4 includes, for example, an inverse prism film 41, the details of which will be described later.

[0016] The liquid crystal of the liquid crystal layer 203 is sandwiched between a pair of glass substrates 202 and sealed with a sealant 204. A voltage is applied to the liquid crystal layer 203 through a drive circuit 205. Based on the applied voltage, the liquid crystal layer 203 controls the polarization of the incident light L1, and the transmittance of the light L1 is controlled.

[0017] Light L1 emitted from the light source 3 enters the optical device 1 from the end surface 11. The light L1 is guided through the optical device 1 by total reflection. The total reflection is broken by the cone structure 2, and the light L1 exits the optical device 1. The light L1 exiting the optical device 1 passes through the optical film 4 and enters the liquid crystal panel 200. The transmittance of the light L1 is controlled by each pixel, and an image pattern is displayed on the liquid crystal display device 300.

[0018] FIG. 2A is a perspective view showing an optical device 1, a cone structure 2 arranged on the optical device 1, and a light source 3. FIG. 2B is a front view of the optical device 1. FIG. 2C is a side view of the optical device 1. The optical device 1 has a cone structure 2 on a surface facing the liquid crystal panel 200 shown in FIG. 1. When the optical device 1 is used as a light guide plate as shown in FIG. 1, the optical device 1 preferably has a plurality of cone structures 2. In FIGS. 2A, 2B, and 2C, one cone structure 2 is extracted and enlarged. An example of the arrangement of the cone structures 2 will be described later.

[0019] The cone structure 2 shown in FIGS. 2A to 2C has a shape of a truncated cone. The cone structure 2 has a side surface 26 and ridge lines 23. At least one ridge line 23 extends in a direction perpendicular to the end face 11 of the optical device 1 on which the light source 3 is provided. More specifically, the cone structure 2 of this embodiment has four ridge lines 23. The cone structure 2 is a plane-symmetric structure. The cone structure 2 has a ridge line 23a extending in a direction perpendicular to the end face 11 of the optical device 1 and a ridge line 23b extending in a direction parallel to the end face 11 of the optical device 1. The ridge line 23a extending in a direction perpendicular to the end face 11 of the optical device 1 is longer than the ridge line 23b extending in a direction parallel to the end face 11 of the optical device 1.

[0020] FIG. 3 is a perspective view showing details of a truncated cone, which is an example of the form of the cone structure 2. The cone structure 2 is a truncated cone and has a lower base 21 and an upper base 24. The lower base 21 has a lower base contour 22. The upper base 24 has an upper base contour 25. The truncated cone has a plurality of side surfaces 26. Each of the plurality of side surfaces 26 connects the lower base 21 and the upper base 24. A ridge line 23 is formed between adjacent side surfaces 26. The truncated cone has a shape in which the side of the cone close to the apex 27 (see FIG. 4A), i.e., the head, of the cone is cut off. The optical properties of the truncated cone are explained based on the optical properties of the cone. To explain the optical properties of the truncated cone, first, the optical properties of the cone are explained. In particular, the optical properties of a square pyramid are explained.

[0021] 4A is a perspective view showing details assuming that the pyramid structure 2 is a square pyramid. The pyramid structure 2 has a lower base 21 as a square pyramid. The lower base 21 has a lower base contour 22. The pyramid structure 2 has a plurality of side surfaces 26. The pyramid structure 2 has an edge line 23. The pyramid structure 2 has a vertex 27. The shape of the pyramid can be represented by a height, which is the distance between the vertex 27 and the lower base 21.

[0022] One triangle is formed by the intersection point Q of one edge 23b with a line that is perpendicular to one edge 23b and passes through the center O of the lower base 21, and the points on both ends of one diagonal line 28a. The interior angle of the intersection point Q of the one triangle forms an edge angle ωL.

[0023] The other triangle is formed by the intersection point S of the other edge line 23c with a line that is perpendicular to the other edge line 23c and passes through the center O of the lower base 21, and the points at both ends of the other diagonal line 28b. The interior angle of the intersection point S of the other triangle forms an edge angle ωS. The shape of the quadrangular pyramid can be expressed by one edge angle ωL and the other edge angle ωS.

[0024] FIG. 4B shows the relationship between the height of the pyramidal structure 2, which is a square pyramid, and the edge angles ωL, ωC. The horizontal axis shows the height, and the vertical axis shows the edge angles ωL, ωC. In the pyramidal structure 2 assumed in FIG. 4B, the length of one diagonal line 28a shown in FIG. 4A is 100 microns, and the length of the other diagonal line 28b is 50 microns. The height is from 10 microns to 100 microns. The value of one edge angle ωL and the other edge angle ωS becomes smaller as the height increases.

[0025] FIG. 5 is a diagram for explaining the definition of the propagation direction of light L1. The propagation direction and emission direction of light L1 are defined by the azimuth angle φ and the tilt angle θ. In FIG. 5, the emission intensity distribution of light L1 is expressed by an approximately elliptical figure. The direction of the line connecting the origin O and the approximately elliptical figure represents the propagation direction of light L1. The length of the line connecting the origin O and the approximately elliptical figure represents the intensity of light L1. The azimuth in which the intensity of light L1 is maximum is indicated by the tilt angle θ and the azimuth angle φ. Below, the explanation will be given using this definition of the direction as appropriate.

[0026] Fig. 6A is a perspective view showing the propagation state of light L1 that enters and exits the pyramidal structure 2. Fig. 6A shows an example in which the pyramidal structure 2 is provided on a surface 12 that is a main light exit surface for light L1 of an optical device 1 functioning as a light guide plate. Light L1 emitted from a light source 3 is guided through the optical device 1. When light L1 enters the pyramidal structure 2, it exits from a point P on a side surface 26. The exit direction of light L1 will be described below with reference to Figs. 6B to 6D.

[0027] 6B and 6C are views of the propagation state of light L1 in the pyramidal structure 2 observed from the Y1 direction. Light L1 is refracted at point P on the side surface 26. FIGS. 6B and 6C show a state in which the pyramidal structure 2 is cut by a plane that passes through point P and is parallel to the XZ plane. In FIG. 6B, the edge angles ωL and ωS are relatively large. In FIG. 6C, which is another example, the edge angles ωL and ωS are relatively small. FIG. 6D is a view of the propagation state of light L1 in the pyramidal structure 2 observed from the Z1 direction.

[0028] FIG. 6B shows the propagation state of light L1 in the optical device 1 and the pyramidal structure 2 when one edge angle ωL and the other edge angle ωS shown in FIG. 4A are large in the pyramidal structure 2 of a square pyramid. FIG. 6B shows the state observed from the Y1 direction. It is assumed that the light L1 propagates in an orientation perpendicular to the end face 11. The line obtained when cutting the pyramidal structure 2 with a plane parallel to the XZ plane is drawn as a line representing the side surface 26. In FIG. 6B, a pair of side surfaces 26 sandwiching the ridge line 23a of the pyramidal structure 2 are arranged at an angle close to parallel to the lower base 21. Light L1a and L1b propagating from the lower base 21 into the pyramidal structure 2 are transmitted through the pair of side surfaces 26. The light L1 is refracted at a point P on the pair of side surfaces 26 on both sides of the ridge line 23a as shown in FIG. 6D. The pair of side surfaces 26 exhibit a light-collecting effect.

[0029] Returning to FIG. 6B, the light L1 is incident on a pair of side surfaces 26 on both sides of the front surface at a shallow angle. That is, the angle of incidence on the pair of side surfaces 26 is relatively small with respect to each side surface 26. The direction in which the light L1 emitted from the pair of side surfaces 26 travels is downward with respect to the surface of the optical device 1 facing the liquid crystal panel 200, as shown by light L1a and light L1b in FIG. 6B. That is, the inclination angle (θ shown in FIG. 5) at which the light L1 travels is 90 degrees or more. Then, the light L1 emitted from the pyramidal structure 2 travels toward the surface 12 of the optical device 1. The light L1 emitted from the pyramidal structure 2 re-enters the optical device 1.

[0030] FIG. 6C shows the propagation state of light L1 in the optical device 1 and the pyramidal structure 2 when one edge angle ωL and the other edge angle ωS shown in FIG. 4A are small in the pyramidal structure 2 of a square pyramid. FIG. 6C shows the case observed from the Y1 direction. It is assumed that light L1 propagates in an orientation perpendicular to the end face 11. A line obtained by cutting the pyramidal structure 2 with a plane parallel to the XZ plane is drawn as a line representing the side surface 26. A pair of side surfaces 26 sandwiching the ridge line 23a of the pyramidal structure 2 are arranged at an angle close to perpendicular to the lower base 21. Light L1c and L1d propagating from the lower base 21 into the pyramidal structure 2 are refracted at a point P on the pair of side surfaces 26. A pair of side surfaces 26 on both sides with respect to the front surface exhibits a light-collecting effect. The angle of incidence on the pair of side surfaces 26 is relatively large with respect to each side surface 26. The direction in which the light L1 emitted from the pair of side surfaces 26 travels is upward with respect to the surface 12 of the optical device 1 facing the liquid crystal panel 200, as shown by light L1c and light L1d in FIG. 6C. That is, the inclination angle (θ shown in FIG. 5) at which the light L1 travels is less than 90 degrees. The light L1 emitted from the cone structure 2 travels in a direction away from the optical device 1.

[0031] In the case where the cone structure 2 is a truncated cone, the optical characteristics of the cone are eliminated in the vicinity of the apex 27 (see FIG. 4A) of the cone. In FIG. 6B, the truncated portion 2x of the cone is indicated by a dashed line. The light L1x indicated by the dashed line is eliminated and replaced with the light L1e described later. FIG. 6B also shows the propagation state of the light L1e in the optical device 1 and the cone structure 2 in this case. The upper base 24 is parallel to the lower base 21, i.e., parallel to the surface 12 of the optical device 1 in the portion where the cone structure 2 does not exist, so that the light L1e is totally reflected by the upper base 24. The optical characteristics can be adjusted by cutting the cone close to the apex 27 as a truncated cone or cutting the cone far from the apex 27. Based on these optical characteristics, the shape of the cone structure 2 is optimized. A plurality of types of cone structures 2 having different ridge angles ωL and ωS may be arranged.

[0032] FIG. 7A is a diagram of the light L1 exiting the pyramidal structure 2 observed from the light input side, that is, from the X1 direction in FIG. 5. FIG. 7B is a diagram of the light L1 exiting the pyramidal structure 2 observed from the front, that is, from the Z1 direction in FIG. 5. As shown in FIG. 7A, the light L1 is emitted, for example, from the Z1 direction at an inclination angle θ (less than 90 degrees). This corresponds to the example shown in FIG. 6C. As shown in FIG. 6D, a pair of side surfaces 26 on both sides of the ridge line 23a play the role of focusing light. As shown in FIG. 7B, the light L1 is emitted from the Y direction, centered on the direction of ±φ, based on the focusing effect. As shown in FIG. 1, the light source 3 is provided at each end of the optical device 1. The light L1 from these two directions enters and exits the pyramidal structure 2. Therefore, as shown in FIG. 7B, the light L1 is emitted in the X1 and X2 directions.

[0033] FIG. 8 shows an embodiment in which a plurality of pyramidal structures 2 are arranged. The size of each pyramidal structure 2 is several tens of μm or less. The pyramidal structures 2 are large enough not to become scattering elements, and small enough that their characteristics are not visible. The pyramidal structures 2 are arranged in a staggered pattern. The arrangement density of the pyramidal structures 2 varies within the optical device 1. The arrangement density of the pyramidal structures 2 is low at a position close to the end face 11. The arrangement density of the pyramidal structures 2 is high at a position far from the end face 11. Light L1 enters the optical device 1 from the end face 11, and a portion of it is emitted from the pyramidal structures 2. Therefore, the amount of light L1 propagating through the optical device 1 decreases with increasing distance from the end face 11. At a position close to the end face 11, a large amount of light guided and a low density of the pyramidal structures 2 are complementary. At a position far from the end face 11, a small amount of light guided and a high density of the pyramidal structures 2 are complementary. The intensity of the emitted light is based on the product of the amount of light guided and the density of the pyramidal structures 2. As a result, a uniform brightness distribution of the emitted light is obtained in the front perpendicular direction within the XY plane of the optical device 1. As shown in FIG. 8, for example, the density of the pyramidal structures 2 is high near the center of the optical device 1. It is preferable to arrange the pyramidal structures 2 densely near the center of the optical device 1. This results in a high emission efficiency of the light L1.

[0034] Here, when the pyramid structure 2 is a quadrangular pyramid or a truncated pyramid as shown in FIG. 2A or FIG. 8, the pyramid structures 2 can be arranged densely with the bottom bases 21 in contact with each other. FIG. 9 is a perspective view showing a state in which a plurality of pyramid structures 2 having a quadrangular pyramid shape are provided on the surface of the optical device 1 facing the liquid crystal panel 200. The bottom base contours 22 of the pyramid structures 2 are in contact with each other. The pyramid structures 2 are arranged without gaps. When changing the arrangement density of the pyramid structures 2 as shown in FIG. 8, the maximum density can be achieved, for example, near the center of the optical device 1. Then, the density of the side surfaces 26 of the pyramid structures 2 can be maximized. As a result, the emission efficiency of the light L1 emitted from the side surfaces 26 of the pyramid structures 2 of the optical device 1 can be maximized.

[0035] Next, the state of the light L1 in the lighting device 100 will be described. Fig. 10A is a cross-sectional view of the lighting device 100. The lighting device 100 has an optical device 1, a light source 3 provided at a side edge, and an optical film 4. The optical film 4 has an inverse prism film 41 and a diffusion film 42. A part of the optical film 4 is illustrated in an enlarged manner. In reality, the size relationship between the optical device 1 and the optical film 4 is different from the relationship illustrated in Fig. 10A.

[0036] 10B to 10D show the light distribution state of light L1 in the lighting device 100. FIG. 10B is a schematic diagram showing the light distribution characteristic of light L1 exiting the liquid crystal panel 200. FIG. 10C is a schematic diagram showing the light distribution characteristic of light L1 exiting the inverse prism film 41. FIG. 10D is a schematic diagram showing the light distribution characteristic of light L1 exiting the optical device 1. FIG. 7A shows light L1 observed from the X1 direction, and FIG. 7B shows light L1 observed from the Z1 direction, while FIG. 10D shows light L1 observed from the Y1 direction.

[0037] As shown in FIG. 1 and FIG. 10A, a pair of light sources 3 are provided. In this case, as shown in FIG. 10D, the light L1 is emitted in two directions. This light distribution characteristic is the same as the light distribution characteristic described with reference to FIG. 7A. The emission direction of this light L1 depends on ωL and ωS shown in FIG. 4A. As shown in FIG. 10D, the light L1 emitted based on the cone structure 2 of the optical device 1 has a shape with a narrow emission direction. In the emitted light L1, the emission of the light L1 in the direction perpendicular to the liquid crystal panel 200 (Z1 direction) is small. As shown in FIG. 10C, the light L1 then passes through the inverse prism film 41. As shown in FIG. 10C, the emission direction of the light L1 has a widening. The amount of the light L1 emitted in the Z1 direction perpendicular to the liquid crystal panel 200 is small. Next, the light L1 passes through the diffusion film 42 shown in FIG. 10A but not shown in FIG. 10B. Furthermore, the light L1 passes through the liquid crystal panel 200 as shown in FIG. 10B. The light distribution characteristic of the light L1 that has passed through the liquid crystal panel 200 is such that a uniform amount of light is emitted in almost all directions.

[0038] Although details will be described later with reference to Fig. 11, the uniform emission amount in all directions is realized because the angular distribution of the transmittance of the liquid crystal panel 200 is complementary to the angular distribution of the light L1 that has passed through the inverted prism film 41 and the diffusion film 42 shown in Fig. 10A but not shown in Fig. 10B. In the front orientation, the small emission amount of light L1 in the front orientation and the high transmittance of the liquid crystal panel 200 compensate for each other. In the oblique orientation where the emission amount of light L1 is large, the large emission amount of light L1 and the low transmittance of the liquid crystal panel 200 compensate for each other.

[0039] FIG. 11 shows the relative intensity of the light L1 emitted from the lighting device 100. Furthermore, FIG. 11 shows the relative transmittance of the liquid crystal panel 200. The horizontal axis is the tilt angle θ from the Z1 direction shown in FIG. 5. The horizontal axis shows the X direction or the Y direction. The positive horizontal axis shows the X1 direction and the Y1 direction. The negative horizontal axis shows the X2 direction and the Y2 direction. The vertical axis shows the relative intensity of the light L1 emitted from the lighting device 100 and the relative transmittance of the liquid crystal panel 200. In FIG. 11, the thick dashed line shows the relative intensity in the X direction of the light emitted from the lighting device 100. In FIG. 11, the thin dashed line shows the relative intensity in the Y direction of the light emitted from the lighting device 100. In FIG. 11, the thick solid line shows the relative transmittance in the X direction of the liquid crystal panel 200. 11, the thin solid line indicates the relative transmittance of the liquid crystal panel 200 in the Y direction.

[0040] 11, the relative intensity of light L1 emitted from the lighting device 100 decreases at angles closer to the front. The relative intensity of light L1 emitted from the lighting device 100 is minimum when the tilt angle θ is 0 degrees, i.e., the display front direction in the Z1 direction. The relative intensity of light L1 emitted from the lighting device 100 increases as the tilt angle θ increases.

[0041] 11, the relative transmittance of liquid crystal panel 200 is higher at angles closer to the front. The relative transmittance of liquid crystal panel 200 is maximum when the tilt angle θ is 0 degrees, i.e., the display front direction in the Z1 direction. The larger the tilt angle θ, the smaller the relative transmittance of liquid crystal panel 200.

[0042] The display luminance of the liquid crystal display device 300 is proportional to the product of the relative transmittance of the liquid crystal panel 200 and the relative intensity of the light L1 emitted from the lighting device 100. The higher characteristic of the relative transmittance of the liquid crystal panel 200 at angles closer to the front and the lower characteristic of the relative intensity of the light L1 emitted from the lighting device 100 at angles closer to the front are mutually compensated for. As a result, the display luminance of the liquid crystal display device 300 is approximately constant at all tilt angles θ. In other words, the display luminance of the liquid crystal display device 300 is constant in all directions, and a Lambertian light distribution is realized.

[0043] (Variation 1) With further explanation, referring to FIG. 9, the optical device 1 has a convex pyramidal structure 2 on the surface 12 of the optical device 1. FIG. 12 shows a modified example 1 in which the optical device 1 has a plurality of pyramidal structures 2, particularly a concave pyramidal structure 2. As shown in FIG. 12, the pyramidal structure 2 has a shape of a quadrangular pyramid. The upper base 24 is provided at the deepest part of the recess. The pyramidal structure 2 is provided on the surface opposite to the surface facing the liquid crystal panel 200. In FIG. 12, the coordinate system is such that the bottom side of the drawing is the Z1 direction, that is, the direction facing the liquid crystal panel 200. In this configuration, the ridge line 23a is also arranged in the X direction. The light L1 guided through the optical device 1 is totally reflected by the side surface 26 of the pyramidal structure 2 and is emitted from the surface facing the liquid crystal panel 200. The ridge line 23 is arranged in the X direction, and the side surface 26 has an angle with respect to the X direction. Therefore, the pair of side surfaces 26 have the effect of a convex mirror. The light L1 has the same light distribution characteristics as those shown in FIGS. 7A and 7B.

[0044] It is also possible to provide the convex pyramidal structure 2 on the back surface 13, which is the surface opposite to the front surface 12 facing the liquid crystal panel 200, and to provide the concave pyramidal structure 2 on the front surface 12 facing the liquid crystal panel 200. The main light emission surface is the front surface 12 facing the liquid crystal panel 200. The pyramidal structure 2 is provided on the back surface 13 opposite to the main light emission surface. In these cases, the light L1 emitted from the pyramidal structure 2 is emitted from the back surface 13 opposite to the front surface 12 facing the liquid crystal panel 200. The light L1 is reflected by the reflective film 5 shown in FIG. 1, re-enters the optical device 1, and is emitted from the front surface 12 facing the liquid crystal panel 200 of the optical device 1. The light L1 reflects the reflection characteristics of the reflective film 5 and shows the same light distribution characteristics as those shown in FIG. 7A and FIG. 7B.

[0045] (Variation 2) In the above-described cone structure 2, when the upper base 24 exists, the upper base 24 has a planar shape. The upper base 24 of the cone structure 2 according to the second modification is recessed toward the lower base 21. FIG. 13 is a perspective view of the cone structure 2 according to the second modification, in which the upper base 24 has a diamond shape. The upper base 24 has a shape in which the apex of the cone faces the lower base 21. The upper base 24 has a ridge line 23. The ridge line 23 includes a ridge line 23a extending in an orientation perpendicular to the end face 11. The light L1 guided in the optical device 1 toward the X2 direction is, for example, totally reflected by the upper bases 24a and 24b, which are inclined surfaces. The light L1 guided in the optical device 1 toward the X1 direction is, for example, totally reflected by the upper bases 24c and 24d, which are inclined surfaces. The reflection angle is different from that of the above embodiment in which the upper base 24 is made of a single plane. Due to the occurrence of total internal reflection, the light L1 can be reflected or guided on both sides of the ridge 23a of the upper base 24. The light L1 guided through the optical device 1 is, for example, refracted and / or guided by the upper bases 24a and 24b, which are inclined surfaces. The refracted light L1 is emitted from the optical device 1.

[0046] (Variation 3) The side surface 26 of the cone structure 2 described above is a plane. Moreover, the lower base contour 22 and the upper base contour 25 are composed of only straight lines. In the cone structure 2 of the modified example 3, as shown in FIG. 14A, the lower base contour 22 and the upper base contour 25 have curved lines. The side surface 26 has a curved surface. The cone structure 2 shown in FIG. 14A has four ridge lines 23. Between a pair of side surfaces 26 on opposite sides of the ridge line 23, the tangents of each pair of side surfaces 26 at the ridge line 23 are discontinuous with each other. To represent this, the ridge lines 23 are represented by straight lines in FIG. 14A. Moreover, the cone structure 2 shown in FIG. 14A is symmetrical both vertically and horizontally. The cone structure 2 has a lower base 21 that is substantially elliptical.

[0047] 14B, the pyramidal structure 2 can have a shape having only two ridges 23. The pyramidal structure 2 has a symmetrical shape that is longer from side to side than from top to bottom.

[0048] (Variation 4) As shown in FIG. 15, the cone structure 2 according to the fourth modification has a ridge 23 not only on the side surface 26 but also in the upper base 24. The side surface 26 is formed of a curved surface. Since the cone structure 2 is transparent, the ridge 23, the upper base contour 25, and the lower base contour 22 are shown in FIG. 15. The upper base 24 has a recessed portion in the center. The upper base 24 has a portion that is not parallel to the XY plane. Therefore, the propagation direction of the light L1 that is totally reflected at the upper base 24 can be changed based on the angle at which the upper base 24 is shifted from the XY plane. Furthermore, the light L1 that is totally reflected as shown by the light L1e in FIG. 6B does not occur and the light L1 that is emitted from the upper base 24 can be obtained. The configuration in which the upper base 24 is not flat can be applied to any truncated cone configuration.

[0049] (Variation 5) In the above embodiment, each of the cone structures 2 has a shape of a cone or a truncated cone alone. The cone structure 2 according to the fifth modification has a configuration in which two or more truncated cones are stacked vertically with a common central axis. FIG. 16A shows an example of a configuration in which two truncated cones are stacked vertically with a common central axis. FIG. 16A is a side view of the cone structure 2, FIG. 16B is a schematic diagram showing the emission of light L1, and FIG. 16C shows the light distribution characteristics. One truncated cone 2a is stacked on the other truncated cone 2b. The lower base contour 22a of one truncated cone 2a is smaller than the upper base contour 25b of the other truncated cone 2b. The cone structure 2 has a flat surface on the upper base 24 of the other truncated cone 2b. The guided light L1 is totally reflected at the flat surface. The light distribution state of the light L1 can be adjusted by the flat surface. As shown in FIG. 16B, light L1 is emitted from the side surface 26 of each truncated cone of the cone structure 2. The light L1 is refracted at the pair of side surfaces 26 due to the light-gathering effect. In FIG. 16B, the symbols given to the ridge lines 23 of one truncated cone 2a and the other truncated cone 2b are not distinguished. The light L1 is emitted toward the Y1 side based on the side surface 26 present on the Y2 side, with the ridge line 23a as the center. The light L1 is emitted toward the Y2 side based on the side surface 26 present on the Y1 side, with the ridge line 23a as the center. In FIG. 16B, the direction of the emitted light as the cone structure 2 in the far field, that is, a position optically distant from the cone structure 2, is shown. As shown in FIG. 16B, in the far field, the emission of the light L1 from the upper base 24a of the truncated cone 2a can be observed. For example, light L1 not satisfying the total reflection condition as shown in Figures 6B and 6C is incident on one truncated cone 2a, and the light L1 is emitted from the upper base 24a of the truncated cone 2a. Figure 16C shows the light distribution characteristic seen from the X1 direction, which is the incident direction of light L1. The light distribution characteristic is controlled by the inclination angle of the side surface 26 of the pair of truncated cones 2a and 2b, the edge angle ωL and the edge angle ωS shown in Figure 4A, the area ratio of the upper base 24 and the lower base 21, the vertical and horizontal dimensional ratio of the truncated cone, etc. Two optical characteristics based on two truncated cones are mixed. Therefore, as shown in Figure 16C, luminance peaks indicated by the inclination angles θ1 and θ2 from the Z1 direction are observed.

[0050] (Variation 6) As shown in Figs. 17A and 17B, in the cone structure 2 according to the sixth modification, one truncated cone 2a overlaps the other truncated cone 2b, as in the fifth modification. Fig. 17A is a side view of the cone structure 2 according to the sixth modification. Fig. 17B is a front view of the cone structure 2 according to the sixth modification. The lower base contour 22a of the one truncated cone 2a and the upper base contour 25b of the other truncated cone 2b are the same. The inclination of the side surface 26a of the one truncated cone 2a is steeper than the inclination of the side surface 26b of the other truncated cone 2b. As a result, the light distribution characteristic described with reference to Fig. 6B is realized by the other truncated cone 2b. The light distribution characteristic described with reference to Fig. 6C is realized by the one truncated cone 2a. Then, a light distribution characteristic that is a mixture of the light distribution characteristic described with reference to Fig. 6B and the light distribution characteristic described with reference to Fig. 6C is realized.

[0051] (Variation 7) The cone structure 2 according to the seventh modification will be described with reference to FIG. 18A and FIG. 18B. FIG. 18A is a cross-sectional view of the cone structure 2 as viewed from the Y1 direction. The cone structure 2 according to the seventh modification has a shape in which one truncated cone 2a overlaps the other truncated cone 2b as in the sixth modification, and the lower base contour 22a of one truncated cone 2a is the same as the upper base contour 25b of the other truncated cone 2b. Unlike the sixth modification, the cone structure 2 is formed as a recess on the back surface 13 opposite to the front surface 12 facing the liquid crystal panel 200 of the optical device 1. As shown in FIG. 18A, the cone structure 2 totally reflects the light L1 guided through the optical device 1 and emits it in the Z1 direction. The light L1a reflected by the side surface 26a and the light L1b reflected by the side surface 26b are mixed in characteristics. For this reason, as shown in Fig. 18B, two luminance peaks are observed at inclination angles θ3 and θ4 from the Z1 direction. As in the fifth modification, the light distribution characteristics are controlled by the inclination angles of the side surfaces 26 of the pair of truncated cones 2a and 2b, the edge angles ωL and ωS shown in Fig. 4A, the area ratio between the upper base 24 and the lower base 21, the vertical and horizontal dimensional ratios of the truncated cone, etc.

[0052] (Variation 8) In the above embodiment, the shape of the lower base 21 of one truncated cone 2a and the shape of the other truncated cone 2b are both quadrangular. The shapes of the upper base 24 and the lower base 21 are not limited thereto, and may be the upper base 24 or the lower base 21 based on the truncated cone as shown in Figures 14A, 14B, and 15.

[0053] (Variation 9) In the above embodiment, as shown in FIG. 8, the optical device 1 has the pyramidal structures 2 whose arrangement density changes in the plane. In the 9th modification, the optical device 1 has the pyramidal structures 2 whose size does not change in the plane and whose arrangement density does not change in the plane. FIG. 19 is a front view of the optical device 1 according to the 89th modification. The pyramidal structures 2 have a relatively small size at a position close to the end face 11. The base of the pyramidal structures 2 may be about 5 μm, and is preferably 200 μm or less. The smaller the pyramidal structures 2, the easier it is to release them from a mold, for example, and the easier they are to make. The aspect ratio of the height and base of the pyramidal structures 2 is, for example, 0.2. For example, the pyramidal structures 2 have a height of 20 μm and a base length of 100 μm. The pyramidal structures 2 have a relatively large size at a position far from the end face 11. Light L1 enters the optical device 1 from the end face 11, and a part of it exits from the pyramidal structures 2. Therefore, the amount of light L1 propagating through the optical device 1 decreases as it moves away from the end face 11. At a position close to the end face 11, the large amount of light guided and the small size of the cone structure 2, i.e., the small surface area that causes the emission, are complementary. At a position far from the end face 11, the small amount of light guided and the large size of the cone structure 2, i.e., the large surface area that causes the emission, are complementary. The intensity of the emitted light is based on the product of the amount of light guided and the size of the surface area that causes the emission. As a result, a uniform intensity of the emitted light in the front perpendicular direction is obtained within the surface of the optical device 1. The arrangement of the cone structures 2 is preferably staggered as shown in FIG. 19. By staggering, it is possible to reduce the possibility that the light L1 emitted from the cone structure 2 is incident on the adjacent cone structure 2. In addition, it is possible to design the angle of the light L1 emitted from the cone structure 2 based on a higher degree of freedom. Here, when the pyramidal structure 2 is a quadrangular pyramid or a truncated quadrangular pyramid, the pyramidal structures 2 can be arranged without gaps with their bottom bases 21 in contact with each other as shown in Fig. 9. The area of ​​the side surface 26 can be maximized. The light L1 is emitted based on the side surface 26. The maximum emission efficiency of the light L1 is realized.

[0054] (Variation 10) In the above embodiment, an example in which the cone structures 2 having the same shape are provided on the optical device 1 is described. This is not limited to the above, and a configuration in which a truncated cone shape, a cone shape, and a shape in which these are overlapped are mixed and arranged on the optical device 1 is possible. For example, a certain density of the cone structures 2 is required to achieve uniformity, and it is desired to reduce the output efficiency near the end face 11. It is preferable to arrange a cone structure 2 having a truncated cone shape with an upper base 24 that performs total reflection near the end face 11, and arrange a cone structure 2 having a cone shape at a site away from the end face 11. It is possible to maintain the same arrangement density and adjust the output efficiency. In the above description, a cone structure 2 in which a truncated cone is overlapped on a truncated cone is described. A shape in which the upper base 24 of the truncated cone is a point is a cone. The above description includes a cone structure 2 in which a cone is overlapped on a truncated cone.

[0055] In the above embodiment, the case where the light L1 is incident on the cone structure 2 from the optical device 1 has been mainly described. However, the present invention is not limited to this, and the light L1 may be emitted from the optical device 1 based on the cone structure 2, be incident on another cone structure 2, pass through the other cone structure 2, and be emitted from the optical device 1. The light L1 may be emitted from the optical device 1 based on the cone structure 2, be incident on another cone structure 2, pass through the other cone structure 2, and be incident on the optical device 1 again, and be guided within the optical device 1.

[0056] (Variation 11) In the above-mentioned modification 9, the size of the cone structures 2 gradually changes regularly. Also, the same shape is adopted for the cone structures 2. However, this is not limited to the above, and multiple cone structures 2 of different sizes and / or shapes may be freely combined. For example, cone structures 2 of different sizes and / or shapes may be randomly arranged to realize an overall uniform light distribution characteristic.

[0057] (Variation 12) In the above embodiment, as shown in a typical example in Fig. 10, the inverse prism film 41 is laminated on the optical device 1 having the cone structure 2. However, the present invention is not limited to this, and the configuration may be one without the inverse prism film 41. Even in this case, the light distribution characteristic shown in Fig. 11 can be realized by optimizing the edge angles ωL and ωS of the cone structure 2, applying the diffusion film 42, etc.

[0058] (Variation 13) In the above embodiment, an example is described in which the cone structure 2 is provided on the optical device 1. From another perspective, this configuration can be said to be such that the film-like optical device 1 provided with the cone structure 2 also serves as a light guide plate made of a plate-like transparent substrate. The present invention is not limited to this, and may be configured such that the film-like optical device 1 provided with the cone structure 2 is laminated on a separate plate-like transparent substrate. Furthermore, another film, such as a diffusion film or an inverted prism film, may be provided between the film-like optical device 1 provided with the cone structure 2 and the separate plate-like transparent substrate.

[0059] (Variation 14) In the above embodiment, the cone structure 2 is arranged with a gradient to reduce luminance unevenness in the plane, as shown in FIG. 8, for example. The cone structure 2 may be arranged uniformly in the plane, as shown in FIG. 20. For example, a case is assumed in which a diffusion pattern is arranged with a gradient on the optical device 1, and the front luminance of the light L1 emitted from the optical device 1 is uniform in the plane. Alternatively, a case is assumed in which the present invention is applied to a direct-type backlight system. For example, a case is assumed in which a plurality of LEDs are arranged and the front luminance is uniform in the plane. A film in which the cone structure 2 is arranged uniformly in the plane is laminated on the optical device 1 in which the front luminance of the light L1 is uniform in the plane. When a film having the cone structure 2 is laminated on the optical device 1 or the direct-type BL, the uniformity is already guaranteed, so the cone structure 2 does not need to be arranged with a gradient. The cone structure 2 only has the function of controlling the light distribution characteristic of the light L1 from the optical device 1 based on the light collecting effect of a pair of side surfaces 26. It is preferable that the cone structure 2 is uniformly arranged in a staggered pattern.

[0060] (Variation 15) In the above embodiment, the optical device 1 and the lighting device 100 are described as being applied to a direct-view type liquid crystal display device 300. The cone structure 2 may be used for lighting. When used as lighting, the lighting device 100 has a plate-shaped transparent optical device 1 having a front surface 12, a back surface 13, and an end surface 11, and has a cone structure 2 with a ridge line 23 facing in a direction perpendicular to the front, back, left, and right end surfaces 11 of the optical device 1. For example, a configuration may be used in which a plurality of LED light sources 3 are provided on the end surface 11. A configuration may be used in which one cone structure 2 is provided on a film. The lighting device 100 may have a configuration in which one LED light source 3 is disposed on the back surface 13 of the optical device 1, light L1 used for lighting is incident perpendicularly on the back surface 13, one cone structure 2 is provided on the front surface 12, and at least a part of the light L1 is transmitted through the cone structure 2. In this case, the light distribution is controlled based on the light collecting effect of a pair of side surfaces 26 of the cone structure 2.

[0061] Various embodiments and modifications of the present disclosure are possible without departing from the broad spirit and scope of the present invention. The above-described embodiments are for the purpose of explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and the scope of the disclosure equivalent thereto are considered to be within the scope of the present invention.

[0062] The approaching moving object detection method according to the embodiment described above provides the following advantages.

[0063] (1) The optical device 1 is a transparent, plate-like optical device 1 having a front surface 12, a back surface 13, and a plurality of end surfaces 11, and is provided with a pyramidal structure 2 on at least one of the front surface 12 or the back surface 13, and the pyramidal structure 2 has a ridge line 23 in a direction perpendicular to at least one of the front, back, left, and right end surfaces 11.

[0064] This makes it possible to provide a light distribution characteristic in which a large amount of light is emitted in a direction inclined from a direction perpendicular to the optical device 1, based on the light collecting effect of the cone structure 2. The light distribution characteristic in the front / rear and left / right directions can also be controlled at the same time.

[0065] (2) In the optical device 1 of (1), the pyramidal structure 2 may have the shape of a truncated pyramid.

[0066] This allows the direction of light L1 to be divided into four or five or more directions. The light-collecting effect based on the portion cut out from the cone as a truncated cone is eliminated, and this can be used to adjust the degree of light collection. In addition, total reflection at the upper base 24 caused by the shape of the truncated cone can be used to adjust the light distribution characteristics.

[0067] (3) The optical device 1 has a plurality of pyramidal structures 2, and the pyramidal structures 2 may be arranged in a staggered pattern.

[0068] This makes it possible to reduce the possibility that the light L1 emitted from the pyramidal structure 2 will re-enter another pyramidal structure 2. It also makes it possible for the light L1 emitted from the pyramidal structure 2 at a shallower angle to contribute to illumination.

[0069] (4) In the optical device 1 of any one of (1) to (3), the pyramidal structure 2 may include a convex structure.

[0070] This makes it possible to utilize the light-collecting effect based on the refraction of the convex parts. It is suitable for injection molding and has good processability.

[0071] (5) In the optical device 1 of any one of (1) to (4), the pyramidal structure 2 may include a concave structure.

[0072] This makes it possible to utilize the light-collecting effect based on the reflection of the recesses. It is suitable for roll-to-roll imprinting and has good processability. It is suitable for uniformly arranging the cone structures 2. It is easy to form a film.

[0073] (6) Any one of the optical devices 1 in (1) to (5) may have a portion in which the pyramidal structures 2 are densely arranged.

[0074] This makes it possible to obtain high emission efficiency.

[0075] (7) In any one of the optical devices 1 of (1) to (6), the cone structure 2 may have a lower base 21 having an elliptical shape.

[0076] This allows distribution of the refraction angle as a light-collecting effect, and makes it possible to control the light-collecting effect.

[0077] (8) In any one of the optical devices 1 of (1) to (7), the pyramidal structure 2 may have a polygonal lower base 21.

[0078] This allows the lower soles 21 to be arranged in contact with one another, thereby increasing the arrangement density.

[0079] (9) In any one of the optical devices 1 of (1) to (8), the pyramidal structure 2 may have a rectangular lower base 21.

[0080] This allows a light collecting effect to be exhibited by a pair of side surfaces 26 sandwiching the ridge line 23. The density of the side surfaces 26 having a certain angle with respect to the end surface 11 can be maximized.

[0081] In any one of the optical devices 1 of (10)(2) to (9), the cone structure 2 may have an upper base 24 having an elliptical shape.

[0082] This allows distribution of the refraction angle as a light-collecting effect, and makes it possible to control the light-collecting effect.

[0083] In any one of the optical devices 1 of (11) (2) to (10), the upper base 24 of the pyramidal structure 2 may be concave toward the lower base 21.

[0084] This makes it possible to control the degree and direction of reflection and refraction of light L1 at the upper base 24.

[0085] (12) In the optical device 1 of any one of (2) to (11), the cone structure 2 may include a configuration in which two or more truncated cones are stacked one on top of the other and have a common central axis.

[0086] This makes it possible to combine different light collecting effects due to different edge angles ωL and ωC, and to utilize the effect of reflection based on the upper base 24 of the truncated cone. The light collecting effect can be adjusted.

[0087] (13) In the optical device 1 of any one of (1) to (12), the pyramidal structure 2 may include a pyramid.

[0088] This allows the proportion of the side surface 26, which is responsible for the light-collecting effect, to be maximized in the cone structure 2. The effective occupancy rate of the side surface 26 in the cone structure 2 is increased. Since there is no upper base 24 in the truncated cone, the number of areas that undergo total reflection can be reduced. As a result, the output efficiency can be increased. The output efficiency of light L1 from each area of ​​the optical device 1 can be adjusted based on the arrangement of the cone structure 2 having the shape of a truncated cone and the cone structure 2 having the shape of a cone.

[0089] (14) The optical device 1 of (1) may have multiple pyramidal structures 2 of different sizes and / or shapes.

[0090] This makes it possible to realize uniform brightness within the plane in the direction perpendicular to the optical device 1. It is possible to realize light distribution characteristics with a high degree of design freedom.

[0091] (15) The lighting device 100 includes a light source 3 and any one of the optical devices 1 of (1) to (13), and at least a portion of the light L1 from the light source 3 may be transmitted through the pyramidal structure 2.

[0092] This allows the lighting device 100 to have the light-collecting effect of the pyramidal structure 2 to be realized.

[0093] (16) In the lighting device 100 of (15), a pyramidal structure 2 may be provided on the emission surface of the main light L1.

[0094] This allows the light L1 that passes through the cone structure 2 to directly contribute to illumination. The light collecting effect of the cone structure 2 can directly contribute to the light distribution of the illumination. This makes it possible to provide light distribution characteristics with less light in the vertical direction and more light in directions tilted from the vertical direction. The light distribution characteristics in the vertical direction can also be controlled at the same time. As a result, the number of optical components can be reduced. It is suitable for injection molding and has good processability.

[0095] (17) In the lighting device 100 of (15) or (16), the pyramidal structure 2 may be provided on the surface opposite to the emission surface of the main light L1.

[0096] The light L1 is reflected on the side opposite to the exit surface of the main light L1, and contributes to display. In the optical device 1, it is possible to increase the efficiency with which the light L1 is emitted from the optical device 1. When a reflective film 5 is provided on the side opposite to the exit surface of the main light L1, the light L1 is reflected by the reflective film 5, and the efficiency with which the light L1 is emitted from the optical device 1 can be increased.

[0097] (18) Any one of the lighting devices 100 (15) to (17) may have an optical device 1 and a light source 3 arranged on an end surface 11 of the optical device 1, and light L1 from the light source 3 may be incident on the optical device 1 from the end surface 11 of the optical device 1.

[0098] This realizes an illumination device 100 having light distribution characteristics in which the amount of light in a direction perpendicular to the optical device 1 is further reduced, and the amount of light in a direction tilted from the direction perpendicular to the optical device 1 is further increased.

[0099] (19) In any one of the lighting devices 100 of (15) to (18), the light source 3 includes at least one of an incandescent lamp, a halogen lamp, a hot cathode fluorescent lamp, a cold cathode fluorescent lamp, a light emitting diode, a laser light device, an inorganic electroluminescent device, and an organic electroluminescent device.

[0100] As the light source 3, any kind of light can be used.

[0101] (20) The liquid crystal display device 300 may include the lighting device 100 according to any one of (15) to (19).

[0102] This makes it possible to stack the lighting device 100 and the liquid crystal panel 200, which emit a small amount of light in a direction perpendicular to the liquid crystal panel 200 and a large amount of light in a direction tilted from the direction perpendicular to the liquid crystal panel 200. The amount of light from the backlight and the transmittance of the liquid crystal panel 200 are complementary, and the liquid crystal display device 300 can achieve Lambertian display characteristics. [Explanation of symbols]

[0103] 1. Optical Devices 11 End face 12 Surface 13 Back side 2. Cone structure 21 Bottom 22 Bottom contour 23 Ridgeline 24 Upper base 25 Upper base contour 26 Side 27 Vertex 3 light source 4. Optical Film 41 Reverse Prism Film 42 Diffusion Film 5. Reflective film 100 Lighting Devices 200 LCD Panel 201 Polarizing plate 202 Glass substrate 203 Liquid crystal layer 204 Sealing material 205 Drive circuit 300 LCD display device L1 light P Points

Claims

1. A transparent plate-like optical device having a front surface, a back surface, and a plurality of end surfaces, A pyramidal structure is provided on at least one of the front surface or the back surface, The pyramidal structure has a ridge line in a direction perpendicular to at least one of the front, rear, left and right end faces. Optical devices.

2. The cone structure has a shape of a truncated cone. The optical device of claim 1 .

3. A plurality of said pyramidal structures are provided, The pyramidal structures are staggered.

3. The optical device according to claim 1 or 2.

4. The cone structure includes a convex structure.

3. The optical device according to claim 1 or 2.

5. The cone structure includes a concave structure.

3. The optical device according to claim 1 or 2.

6. The pyramidal structures have a portion where they are densely arranged.

3. The optical device according to claim 1 or 2.

7. The cone structure has an elliptical bottom base.

3. The optical device according to claim 1 or 2.

8. The pyramidal structure has a polygonal base.

3. The optical device according to claim 1 or 2.

9. The pyramidal structure has a quadrangular lower base.

9. The optical device of claim 8.

10. The upper base of the truncated cone has a substantially elliptical shape.

3. The optical device of claim 2.

11. The upper base of the truncated cone is recessed toward the lower base.

3. The optical device of claim 2.

12. The cone structure includes two or more truncated cones stacked on top of each other with a common central axis.

3. The optical device according to claim 1 or 2.

13. The pyramidal structure has a pyramidal shape. The optical device of claim 1 .

14. Having a plurality of said cone structures of different sizes and / or shapes; The optical device of claim 1 .

15. A light source and the optical device according to claim 1 or 2, At least a portion of the light from the light source is transmitted through the cone structure. Lighting device.

16. The cone structure is provided on the main light exit surface.

16. A lighting device according to claim 15.

17. The cone structure is provided on the surface opposite to the main light exit surface.

16. A lighting device according to claim 15.

18. The optical device; the light source is disposed on the end surface of the optical device; Light from the light source is incident on the optical device from the end surface of the optical device.

16. A lighting device according to claim 15.

19. The light source includes at least one of an incandescent lamp, a halogen lamp, a hot cathode fluorescent lamp, a cold cathode fluorescent lamp, a light emitting diode, a laser light device, an inorganic electroluminescence device, and an organic electroluminescence device.

16. A lighting device according to claim 15.

20. A liquid crystal display device comprising the lighting device according to claim 15.

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