WO2008065906A1

WO2008065906A1 - Light guide body and illumination device

Info

Publication number: WO2008065906A1
Application number: PCT/JP2007/072223
Authority: WO
Inventors: Akira Sugiyama
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-11-29
Filing date: 2007-11-15
Publication date: 2008-06-05
Also published as: JP2008140550A

Abstract

A light guide body in which luminance variation when light is caused to enter the light guide body from a portion of one side of the body is minimized. The light body (1) has a first light path change section (21) and second light path change section (22) that are in that incident region (S1) of a first side (11) where light emitting elements (12) are arranged facing each other. The first light path change section (21) is formed such that light enters directly to it from the light emitting elements (12) and refracts the incident light such that the absolute value of the angle formed between the light and a reference line (L) perpendicular to an end surface (11a) of the first side (11) is greater. The second light path change section (22) is formed at a position away from the end surface (11a) of the first side (11) and other than the position of a light path (31) of light having passed the first light path change section (21). Light emitted from the light emitting elements (12) is reflected such that the absolute value of the angle formed between the light and the reference line (L) perpendicular to the end surface (11a) of the first side is greater.

Description

Specification

Light guide and lighting device

Technical field

The present invention relates to an illumination device for illuminating an object, for example, an illumination device for illuminating a liquid crystal display panel included in a liquid crystal display device, and a light guide provided in the illumination device.

Background art

A surface illumination type illumination device called a backlight device is used for illumination of a transparent liquid crystal display panel provided in a liquid crystal display device such as a liquid crystal display device and a liquid crystal television device. Liquid crystal display devices used as display means for mobile terminal devices such as mobile phone devices and personal digital assistance (abbreviated as PDA) are plate-shaped light guides (hereinafter referred to as “light guide plates”) as surface illumination type illumination devices. An edge light type illuminating device in which a light source is provided opposite to one side portion is used.

Cold Cathode Fluorescent Lamp (abbreviated as CCFL) has been widely used as a light source for knocklight devices. Reasons such as ease of thinning and consideration for the environment, light-emitting diodes ( Replacement with Light Emitting Diode (abbreviation LED) is progressing. Since LEDs are highly directional, when they are used as the light source of an edge-light type lighting device, a difference in brightness occurs between the part of the light guide plate facing the LED and the other parts, resulting in uneven brightness. Due to this uneven brightness, the display quality of the liquid crystal display device is degraded.

An example of a conventional light guide plate is disclosed in Japanese Patent Application Laid-Open No. 2004-192937. 16A is a plan view showing an example of the configuration of the conventional light guide plate 100, FIG. 16B is an enlarged plan view showing the introduction portion 101 of the light guide plate 100 shown in FIG. 16A, and FIG. 17 is shown in FIG. 16A. 2 is a plan view schematically showing a light guide plate 100. FIG. FIG. 17 shows a case where three introduction parts 101 are provided for easy understanding. The light guide plate 100 includes a plurality of introduction portions 101 at a portion where light is incident from the light source 102 in order to suppress luminance unevenness. In each introduction unit 101, the light incident from the light source 102 is collected by the light collection unit 103, and the inclined surface 104 of the light diffusion unit 104 is collected. Reflected by a and incident on the reflecting surface 105. The light incident on the reflecting surface 105 is reflected by the reflecting surface 105, is emitted from the introduction unit 101 in parallel with the light guide direction A, and enters the daylighting unit 106. Although not related to the light guide plate, Japanese Patent Application Laid-Open No. 2005-135844 discloses that as a technology related to suppressing uneven brightness, an optical element is provided between the light guide plate and the light source, and the light emitting surface of the light source of this optical element is in contact with the light source plate. A technique for forming a diffusion prism such as a cylindrical lens on the light incident surface and diffusing the light incident from the light source with the diffusion prism is disclosed! No. 215346, JP-A 2004-259688 and JP-A 2006-154292. FIG. 18 is an enlarged plan view showing another example of the configuration of the conventional light guide plate 110. In order to suppress uneven brightness, the light guide plate 110 has a hole 113 in which, for example, a triangular prism-shaped hole is formed in the incident region S1 facing the light source 112 of the one side 111. In the light guide plate 110 shown in FIG. 18, a plurality of hole portions 113 are continuously formed along the end surface 111 a of the one side portion 111.

FIG. 19 is an enlarged plan view showing still another example of the configuration of the conventional light guide plate 120. A light guide plate 120 shown in FIG. 19 has a hole 113 similar to that of the light guide plate 110 shown in FIG. In the light guide plate 120 shown in FIG. 19, the number of the hole portions 113 is smaller than that of the light guide plate 110 shown in FIG. 18, and the plurality of hole portions 113 are formed at intervals.

In the light guide plate 100 shown in FIGS. 16 and 17, it is necessary to provide the introduction unit 101 separately from the force lighting unit 106 that can suppress uneven luminance in the lighting unit 106. The part provided with the introduction part 101 is an invalid display area 107 that cannot be used for illumination, and is arranged in an area outside the display area in the display device.

In the technique disclosed in Japanese Patent Application Laid-Open No. 2004-192937, if the arrangement interval of the light sources 102 is widened for reasons such as an increase in the size of the display screen of the liquid crystal display device and a reduction in the number of light sources for cost reduction, The width dimension in the direction perpendicular to the light guide direction A (hereinafter simply referred to as “width dimension”) W increases. In the technique disclosed in Japanese Patent Application Laid-Open No. 2004-192937, light is reflected by the reflecting surface 105 in parallel to the light guide direction A. Therefore, the larger the width dimension W of the introduction portion 101 is, the greater the light guide direction A of the introduction portion 101 is. It is necessary to increase the length dimension in the parallel direction (hereinafter simply referred to as “length dimension”). The increase in the length dimension H of the introduction part 101 causes the enlargement of the invalid display area 107 including the introduction part 101 and the light source 102 which are the areas! . Therefore, the technique disclosed in Japanese Patent Application Laid-Open No. 2004-192937 is difficult to reduce in design.

In the technique disclosed in Japanese Patent Laid-Open No. 2005-135844, an optical element is provided between the light guide plate and the light source. In addition, since light incident on the diffusion prism of the optical element from the light source is emitted toward the light guide plate, the light cannot be guided to a region outside the incident region where the light incident surface of the optical element is formed. Therefore, even if the technique disclosed in Japanese Patent Laid-Open No. 2005-135844 is applied to the light guide plate and a diffusing prism is formed in the incident region of the light guide plate, light cannot be guided to the region outside the incident region.

When holes are formed as in the techniques disclosed in Japanese Patent Laid-Open Nos. 2003-215346, 2004-259688, and 2006-154292, for example, a light guide plate 110 shown in FIG. The hole 113 is formed continuously. When the hole 113 is continuously formed as described above, the light 114 incident on the hole 113 from the light source 112 is refracted when passing through the boundary 113 a of the hole 113. The light that has passed through the boundary 113a of the hole 113 enters the hole 113 adjacent to the hole 113. A part of the light incident on the adjacent hole 113 is reflected by the adjacent hole 113 and is totally reflected in some cases, and is directed to the inward direction of the incident region S 1 by a reference numeral 115 which is a direction. Proceed in the direction of the solid line shown. The light 114 incident on the hole 113 is refracted and passes through the boundary 113a of the two or more holes 113, and then reflected by the hole 113 to generate an inward force or force on the inside of the incident region S1. It may also proceed in the direction of the solid line indicated by reference numeral 115.

In this way, when the hole 113 is continuously formed! /, The light incident on the light guide plate 110 passes through the boundary 113a of the hole 113 once or several times, and then enters the boundary 113a. It tends to be reflected toward the inside of area S1. Therefore, it is difficult to guide the light incident on the hole 113 to the region S2 outside the incident region S1 of the one side portion 111.

FIG. 20 is a diagram illustrating a simulation result of a light guide state of light incident on the light guide plate 110. FIG. 20 shows a simulation result when one light source 112 is used. In FIG. 20, each straight line extending radially from the light source 112 is the light of the light incident on the light guide plate 110. Showing the road.

From the simulation results shown in FIG. 20, in the light guide plate 110, the light incident from the light source 112 is less guided to the region S2 outside the incident region of the one side 111, and the region outside the projection region S3 of the light source 112. It is clear that less light is guided to S4. Therefore, in the technique shown in FIG. 18, a difference in luminance occurs between the incident region S1 on one side 111 and the region S2 outside the incident region, resulting in uneven luminance. Further, the light guide plate 120 shown in FIG. 19 has a luminance difference between the projection region S3 of the light source 112 near the one side 111 and the region S4 outside the projection region. Holes 113 are formed at intervals. When a plurality of holes 113 are formed at such intervals, the light 114 incident on the holes 113 does not enter the other holes 113 after passing through the boundary 113a. Then, the directional force is directed outward from the incident area S 1 and proceeds in the direction of the solid line indicated by reference numeral 121, which reaches the area S 2 outside the incident area S 1 on the one side portion 111.

Thus, in the light guide plate 120, the force that can prevent reflection by the adjacent hole 113, the light 122 incident on the incident region S1 between the two adjacent holes 113 does not enter the hole 113. It proceeds without changing the direction of travel when incident, and does not reach the region S2 outside the incident region S1 of the one side 111. Therefore, since the amount of light reaching the region S2 outside the incident region is small, the difference in luminance between the incident region S1 and the region S2 outside the incident region cannot be sufficiently suppressed, and the luminance unevenness is sufficiently reduced. I can't suppress it.

FIG. 21 is a diagram illustrating a simulation result of a light guide state of light incident on the light guide plate 120. FIG. 21 shows a simulation result when one light source 112 is used. In FIG. 21, each straight line extending radially from the light source 112 indicates the optical path of the light incident on the light guide plate 120.

From the simulation results shown in FIG. 21, in the light guide plate 120, light is guided to a wider range of the region S2 outside the incident region in the region S4 outside the projection region of the light source 112 than in the light guide plate 110. It can be seen that the amount is small. Therefore, in the technique shown in FIG. 19, the difference in luminance between the incident region S1 on one side 111 and the region S2 outside the incident region cannot be sufficiently reduced as described above, and the luminance unevenness is sufficiently increased. Can not be suppressed. One more Since the difference in brightness between the projection area S3 of the light source 112 near the side 111 and the area S4 outside the projection area cannot be reduced sufficiently, the brightness unevenness of the entire light guide plate 120 can be sufficiently suppressed. I ca n’t.

Disclosure of the invention

The objective of this invention is providing the light guide which can suppress the brightness nonuniformity when light injects from a part of one side part, and an illuminating device provided with the same.

The present invention is a light guide that diffuses and emits incident light,

One side where light is incident;

Including at least one main surface that emits diffused light,

One side has an incident region provided with a light source facing the light source,

In the incident area,

A first optical path changing unit that directly irradiates light from a light source and refracts the incident light so that an absolute value of an angle formed with a reference line perpendicular to an end surface of one side is increased; and one side Is formed at a position that is spaced from the end face of the light source and avoids the light path of the light that has passed through the first light path changing section, and allows the light incident from the light source to be perpendicular to the end face of one side. And a second optical path changing unit that reflects or refracts so that the absolute value of the formed angle is large.

In the present invention, it is preferable that at least one of the first and second optical path changing portions is formed by forming a hole in one side portion.

In the present invention, the holes are preferably filled with a filler.

Moreover, in this invention, it is preferable to have the radiation | emission prevention part which prevents that the light incident from the light source radiate | emits outside in the other side part except one side part.

In the present invention, the emission preventing portion is formed by forming the end surface of the other side portion into a curved surface convex outwardly.

In the present invention, the emission preventing portion is preferably formed by forming a notch on the other side portion.

In the present invention, it is preferable that at least one of the main surfaces is formed into a rough surface. In the present invention, it is preferable that the other surface portion except the surface portion on which the main surface for emitting light incident from one side is formed has a reflecting portion for reflecting incident light. Better!/,. Moreover, this invention is an illuminating device provided with the light guide of the said this invention, and the light source which is provided facing the incident area of a light guide, and injects light into an incident area.

Brief Description of Drawings

Objects, features and advantages of the present invention will become more apparent from the following detailed description and drawings.

FIG. 1 is a plan view showing a part of the light guide according to the first embodiment of the present invention.

FIG. 2 is a plan view showing the light guide according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view showing an exploded view of the lighting device 2 including the light guide according to the first embodiment of the present invention.

FIG. 4 is a diagram for explaining dimensions and arrangement intervals of the first and second optical path changing units shown in FIG.

FIG. 5 is a diagram illustrating a simulation result of a light guide state of light incident on the light guide according to the first embodiment.

FIG. 6 is a plan view showing a part of a light guide in which a hole formed in the first and second optical path changing portions is filled with a filler.

FIG. 7 is a plan view showing a part of the light guide according to the second embodiment of the present invention.

FIG. 8 is a diagram for explaining the light refraction state on the third and fourth second optical path changing surfaces of the second optical path changing unit.

FIG. 9 is a diagram illustrating a simulation result of a light guide state of light incident on the light guide body according to the second embodiment.

FIG. 10 is a plan view showing a part of the light guide according to the third embodiment of the present invention.

FIG. 11 is a plan view showing a part of the light guide according to the fourth embodiment of the present invention.

FIG. 12 is a plan view showing a part of the light guide according to the fifth embodiment of the present invention.

FIG. 13 is a plan view showing a light guide according to a sixth embodiment of the present invention.

FIG. 14 is a plan view showing a light guide body having an emission preventing portion formed by forming a notch in the side portion. FIG. 15 is a plan view showing a light guide according to a seventh embodiment of the present invention.

FIG. 16A is a plan view showing an example of the configuration of a conventional light guide plate, and FIG. 16B is an enlarged plan view showing an introduction portion of the light guide plate shown in FIG. 16A.

FIG. 17 is a plan view schematically showing the light guide plate shown in FIG. 16A.

FIG. 18 is an enlarged plan view showing a configuration of another conventional light guide plate.

FIG. 19 is an enlarged plan view showing a configuration of a light guide plate of still another conventional example. FIG. 20 is a diagram illustrating a simulation result of a light guide state of light incident on a light guide plate of another conventional example.

FIG. 21 is a diagram illustrating a simulation result of a light guide state of light incident on a light guide plate of still another example of the related art.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view showing a part of the light guide 1 according to the first embodiment of the present invention, and FIG. 2 is a plan view showing the light guide 1 according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view showing the illuminating device 2 including the light guide 1 according to the first embodiment of the present invention in an exploded manner. FIG. 1 shows an enlarged view of one side 11 of the light guide 1 shown in FIG.

The light guide 1 is provided, for example, in the illumination device 2 shown in FIG. The illuminating device 2 shown in FIG. 3 is a device for illuminating an object with illumination light, and is provided in a transmissive liquid crystal display device, for example, and used as a backlight device that illuminates a liquid crystal display panel. In the liquid crystal display device, the illuminating device 2 is provided facing the liquid crystal display panel, and the liquid crystal display panel, which is an object, illuminates the liquid crystal display panel as an object from the side opposite to the side on which the operator views the display screen. The illumination device 2 is not limited to the illumination of the liquid crystal display panel, but may be used for illumination of other objects or innomination.

The illuminating device 2 shown in FIG. 3 is an edge light type illuminating device in which a light source 12 is provided to face one side 11 of the light guide 1. The illumination device 2 includes the light guide 1 of the present embodiment and a light emitting element 12 that is a light source. In the present embodiment, a plurality of light emitting elements 12 are provided, more specifically, three. The light emitting element 12 that is a light source emits light radially toward the light guide 1. The light emitting element 12 is realized by a light emitting diode (abbreviated as LED), for example. As shown in FIG. 3, the light guide 1 has a flat plate shape, and the surfaces on both sides in the thickness direction are main surfaces la and lb. The light guide 1 diffuses light incident from the first side 11 which is one side, and at least one of the two main surfaces la and lb, one main surface in the present embodiment. Emits from la. Hereinafter, one main surface la from which the light is emitted is referred to as an emission surface la, and the other main surface opposite to the emission surface la is referred to as a back surface lb.

In the present embodiment, the light guide 1 has a parallel plate shape, and the surfaces on both sides in the thickness direction, which are the emission surface la and the back surface lb, of the light guide 1 are formed in planes substantially parallel to each other. As described above, the shape of the light guide 1 is a parallel plate shape in which the surfaces on both sides in the thickness direction are parallel to each other in the present embodiment. However, the shape is not limited to this. It may be a wedge shape that is inclined with respect to the surface on the other side in the thickness direction, or a shape in which a parallel plate portion and a wedge portion are combined.

The thickness direction of the light guide 1 is defined as the Z direction, one direction perpendicular to the Z direction is defined as the X direction, and the direction perpendicular to the Z direction and the X direction is defined as the Y direction. In each figure, these X, Υ, and Ζ directions are represented by arrows X, Υ, and Ζ.

As shown in FIG. 2, the light guide 1 has a rectangular plate shape whose long side is parallel to the flange direction. In Fig. 2, one side Z1 is the direction perpendicular to the paper surface, and the direction of force toward the front side of the paper surface. The first side portion 11 of the light guide 1 is a short side on one side of the ridge direction, out of two short sides parallel to the X direction. More specifically, the light guide 1 includes a light guide body 25 and a reflective layer 26.

The reflection layer 26 is formed on the end surfaces of the side portions on both sides in the X direction of the light guide body 25, and is the side portions on both sides in the X direction of the light guide body 1 together with the side portions on both sides in the X direction of the light guide body 25. 2 and 3 side parts 27 and 28 are formed. The second and third side portions 27 and 28 of the light guide 1 correspond to a reflecting portion. The reflective layer 26 is formed so as to have a reflectance of approximately 1.0 with respect to incident light. As the material of the reflective layer 26, a material having high light reflectivity and a reflectance close to 1.0 is used. Examples of such a material include silver (Ag) and aluminum (A1). The reflective layer 26 is realized by a thin film having a reflectance close to 1.0, for example. The light guide body 25 has translucency and is made of a translucent material such as translucent resin such as acrylic resin and polycarbonate resin.

The light guide 1 has an incident area in which a light emitting element 12 as a light source is opposed to a first side 11. The incident region SI has a first optical path changing unit 21 and a second optical path changing unit 22 shown in FIG. In FIG. 2, the incident region S 1 on the first side portion 11 is indicated by a right-down oblique line, and the region S 2 outside the incident region on the first side portion 11 is indicated by a left-down oblique line. In the present embodiment, since the lighting device 2 includes the three light emitting elements 12, three incident regions S1 are formed. The incident area S 1 of the first side portion 11 is an area where the light emitting surface 12a of the light emitting element 12 as the light source in the light guide 1 is projected onto the other Y2 in the Y direction (hereinafter referred to as “projection area of the light emitting element 12”). This region is included in S 3 and is included in the first side portion 11 in the projection region S 3 of the light emitting element 12. The area S2 outside the incident area of the first side portion 11 is included in the area S4 outside the projection area of the light emitting element 12 in the light guide 1, and the area S4 outside the projection area of the light emitting element 12 is within the area S4. 1 side 1 1 is an area included in 1

As shown in FIG. 1, the first optical path changing unit 21 is formed so that light is directly incident from the light emitting element 12. The first optical path changing portion 21 is formed by forming a hole in the first side portion 11 of the light guide 1, more specifically, a through hole penetrating the first side portion 11 in the thickness direction. In the first hole portion 21 that is the first optical path changing portion, a hole whose opening shape in the XY plane that is a virtual plane perpendicular to the Z direction that is the thickness direction of the light guide 1 is trapezoidal is formed. ing. The hole of the first hole portion 21 has a uniform shape in the Z direction, and is a trapezoid arranged in the XY plane perpendicular to the Z direction. More specifically, the upper base and the lower base are the end faces of the first side portion 11 ( (Hereinafter sometimes referred to as “first side end face”) An isosceles trapezoid that is parallel to 11a and is located on the first side end face 11a side of the upper base is longer in the Z direction. is there.

In the first optical path changing unit 21, two planar first optical path changing surfaces 23, that is, a first first optical path changing surface 23a and a second first optical path changing surface 23b are formed. The planes formed by extending the oblique sides of the trapezoid arranged in the XY plane perpendicular to the Z direction in the direction correspond to the first and second first optical path changing surfaces 23a and 23b. In the present embodiment, the first and second first optical path changing surfaces 23a and 23b are formed to have the same dimensions.

The first and second first optical path changing surfaces 23a, 23b are planes inclined from the first side end surface 11a, which is the end surface of the first side portion 11, and the first and second first optical path changing surfaces 23a, 23b It is formed so that the opening area in the ZX plane which is a virtual plane parallel to the first side end face 1 la of the hole 21 is small. The first first optical path changing surface 23a is the second first optical path changing surface 23b. It is formed on one XI side than the X direction. The first first optical path changing surface 23a is formed so as to incline from the imaginary plane perpendicular to the first side end surface 11a toward the other X2 side in the X direction as it is farther from the first side end surface 11a. The second first optical path changing surface 23b is formed so as to be inclined toward the XI side in the X direction from a virtual plane perpendicular to the first side end surface 11a as the distance from the first side end surface 11a increases.

The first optical path changing unit 21 is formed to have a refractive index higher than the refractive index in the hole. Since the hole formed in the first optical path changing unit 21 is a cavity in this embodiment, the refractive index in the hole is about 1.0, which is substantially equal to the refractive index of air. The first optical path changing unit 21 is included in the light guide body 25, and the light guide body 25 is formed of a material having a refractive index higher than that of air, specifically, a light-transmitting resin such as talyl resin. .

The first optical path changing surface 23 is formed so that the opening area in the ZX plane parallel to the first side end surface 11a of the hole of the first hole portion 21 decreases as the distance from the first side end surface 11a increases. The light incident on the first optical path changing surface 23 is bent so as to be bent toward the Y1 side in the Y direction, and is guided to the region S2 outside the incident region S1 of the first side portion 11.

As described above, the first optical path changing unit 21 refracts the light directly incident from the light emitting element 12 so that the absolute value of the angle formed with the reference line L perpendicular to the first side end surface 11a is increased. In other words, the first optical path changing unit 21 is positive (+) on the other side in the X direction from the reference line L perpendicular to the first end surface 11a, and negative (one) on the XI side in the X direction. The absolute value of the angle α2 between the optical path 31 of the light that has passed through the first optical path changing section 21 and the reference line L I «2 I force S, the light incident on the first optical path changing section 21 from the light emitting element 12 The incident light is refracted so that the angle between the optical path 30 and the reference line L is larger than the absolute value I α 1 I of << 1. Thereby, the light incident from the light emitting element 12 is guided to the region S2 outside the incident region S1 of the first side portion 11.

The second optical path changing unit 22 is formed at a position away from the first side end surface 11a, which is the end surface of the first side unit 11, and avoiding the optical path 31 of the light that has passed through the first optical path changing unit 21. Is done. The second optical path changing portion 22 is formed by forming a hole in the first side portion 11 of the light guide 1, more specifically, a through hole penetrating the first side portion 11 in the thickness direction. In the present embodiment, the holes formed in the first and second optical path changing portions 21 and 22 are formed continuously.

The second hole portion 22 which is the second optical path changing portion is connected to the hole of the first hole portion 21, and the light guide 1 A hole having a trapezoidal opening in the XY plane perpendicular to the Z direction, which is the thickness direction, is formed. The hole of the second hole portion 22 has a uniform shape in the heel direction, and is a trapezoid arranged on the heel plane perpendicular to the heel direction. More specifically, the upper base and the lower base are parallel to the first side end face 11a. In this case, an isosceles trapezoid with a lower bottom, which is arranged closer to the first side end face 11a than the upper base, extends in the Z direction.

In the second optical path changing unit 22, two planar second optical path changing surfaces 24, that is, a first second optical path changing surface 24a and a second second optical path changing surface 24b are formed. The planes formed by extending the oblique sides of the trapezoid arranged in the XY plane perpendicular to the Z direction in the direction correspond to the first and second second optical path changing surfaces 24a and 24b. In the present embodiment, the first and second second optical path changing surfaces 24a and 24b are formed to have the same dimensions.

The first and second second optical path changing surfaces 24a, 24b are planes inclined from a virtual plane parallel to the first side end surface 11a that is the end surface of the first side portion 11, and from the first side end surface 11a. Accordingly, the opening area in the ZX plane parallel to the first side end surface 11a of the hole of the second hole portion 22 is increased. The first second optical path changing surface 24a is formed closer to the XI side in the X direction than the second second optical path changing surface 24b. The first second optical path changing surface 24a is formed so as to incline from the imaginary plane perpendicular to the first side end surface 11a toward the one XI side in the X direction as the distance from the first side end surface 11a increases. The second second optical path changing surface 24b is formed so as to be inclined from the imaginary plane perpendicular to the first side end surface 11a toward the other X2 side in the X direction as it is farther from the first side end surface 11a.

In the present embodiment, the first optical path changing surface 23 and the second optical path changing surface 24 are positive (+) on the other side in the X direction from the reference line L perpendicular to the first side end surface 11a, and negative on the one side in the X direction. In (1), the angle between the second optical path change surface 24 and the reference line L is the absolute value of Θ 2 I Θ 2 I force S, the angle between the first optical path change surface 23 and the reference line L θ It is formed so as to be larger than the absolute value I Θ 1 I of 1.

The second optical path changing unit 22 is formed to have a refractive index higher than the refractive index in the hole. Since the hole formed in the second optical path changing unit 22 is a cavity in this embodiment, the refractive index in the hole is about 1.0, which is substantially equal to the refractive index of air. The first optical path changing unit 21 is included in the light guide body 25, and the light guide body 25 is made of a material having a refractive index higher than air, specifically, an It is made of a translucent resin such as a ruthenium resin.

The second optical path changing surface 24 is formed so that the opening area in the ZX plane parallel to the first side end surface 11a of the hole of the second hole portion 22 increases as the distance from the first side end surface 11a increases. The light incident on the first optical path changing surface 23 is reflected so as to be bent toward the Y1 side in the Y direction, and is guided to the region S2 outside the incident region S1 of the first side portion 11.

As described above, the second optical path changing unit 22 reflects the light incident from the light emitting element 12 so that the angle formed by the reference line L perpendicular to the first side end face 11a is increased. That is, when the second optical path changing unit 22 is positive (+) on the other side in the X direction and negative (one) on the one side in the X direction from the reference line L perpendicular to the first side end surface 11a, the second optical path changing unit 22 The angle formed between the optical path 33 of the light reflected by the optical path changing unit 22 and the reference line L / 3 2 absolute value I / 3 2 I force of light incident on the second optical path changing unit 22 from the light emitting element 12 The incident light is reflected so that the angle between the optical path 32 and the reference line L is larger than the absolute value I / 3 1 I of / 31. Thereby, the light force incident from the light emitting element 12 is guided to the region S2 outside the incident region S1 of the first side portion 11.

“An angle between the optical path and the reference line L” refers to the intersection between the optical path and the reference line L, and the reference line L between the optical path and the reference line L on the other side in the Y direction, that is, the light guide direction side. It is an angle. The “angle between the optical path change plane and the reference line L” refers to the reference line L on the other side of the light guide direction with respect to the intersection of the optical path change plane and the reference line L in the Y direction, which is closer to the light guide direction. Is the angle formed by the optical path change plane.

FIG. 4 is a diagram for explaining the dimensions and arrangement intervals of the first and second optical path changing units 21 and 22 shown in FIG. The dimensions and arrangement intervals of the first and second optical path changing sections 21 and 22 are selected according to the dimension wO in the X direction of the light emitting surface 12a of the light emitting element 12 as the light source.

For example, when the dimension wO in the X direction of the light emitting surface 12a of the light emitting element 12 is about 2.5 mm, the maximum dimension wl in the X direction of the second optical path changing unit 22 is selected as 80.O ^ m, The dimension _W 2 in the X direction of the opening end of the connecting portion 34 between the optical path changing portion 21 of 1 and the second optical path changing portion 22 is selected as 10.O ^ m, and the X of the first optical path changing portion 21 The maximum dimension w3 in the direction is chosen as 15. 3 111, the dimension hi in the Y direction of the second optical path changer 22 is chosen as 35.O ^ m, and the dimension h2 in the Y direction of the first optical path changer 21 Is 15. O ^ m And the arrangement interval p between the first and second optical path changing units 21 and 22 is selected to be 100.0 m. The dimensions and arrangement intervals of the first and second optical path changing units 21 and 22 are not limited to the above values.

In the present embodiment, the maximum dimension wl in the X direction of the second optical path changing unit 22 is the first and second second optical path changing surfaces 24a and 24b of the second hole 22 which is the second optical path changing unit. The remaining inner wall 24c is the dimension in the X direction of the remaining inner wall surface 24c, and the maximum dimension w3 in the X direction of the first optical path changing section 21 is the first side of the first hole 21 that is the first optical path changing section. It is the dimension in the X direction of the opening edge on the end face 11a side.

Further, the arrangement interval p of the first optical path changing portions 21 is set in the X direction of the opening end portion on the first side end face 11a side of the two adjacent first optical path changing portions 21 in the XY plane perpendicular to the thickness direction Z. In the XY plane perpendicular to the thickness direction Z, the arrangement distance p of the second optical path changing sections 22 is the distance between the centers in the X direction of the inner wall surface 24c of the two adjacent second optical path changing sections 22. This is the distance between the centers. In the present embodiment, the first and second optical path changing units 21 and 22 are the X direction of the remaining inner wall surface 24c excluding the first and second second optical path changing surfaces 24a and 24b of the second optical path changing unit 22. Are arranged symmetrically with respect to a virtual plane that is perpendicular to the first side end face 11a, so that the arrangement interval p of the first optical path changing unit 21 and the arrangement interval p of the second optical path changing unit 22 are Are in agreement!

As described above, the light guide 1 of the present embodiment has the first and second optical path changing units 21 and 22 in the incident region S 1 of the first side portion 11. As a result, of the light incident on the incident region S1 from the light emitting element 12, the light directly incident on the first optical path changing unit 21 is refracted by the first optical path changing unit 21 to be refracted by the first side part. 11 The incident area S1 is guided to the area S2 outside the incident area S1, and the light incident on the second optical path changing section 22 is reflected by the second optical path changing section 22 to be the area outside the incident area S1 on the first side section 11. Can lead to S2. Therefore, the luminance difference between the incident area S1 of the first side portion 11 and the area S2 outside the incident area S1 can be reduced, and uneven luminance can be suppressed. In the light guide plate 110 shown in FIG. 18 described above, a plurality of hole portions 113 into which light is directly incident from the light source 112 are continuously formed on the side portion 11! /, So that two adjacent hole portions 113 are formed. Of these, one hole 113 is located in the optical path of the light 115 that has passed through the other hole 113. Therefore, it passes through the hole 113 other than the hole 113 formed at both ends in the X direction of the incident region S1. Since the optical path of the light 115 is changed in the other hole 113, the light 114 incident on the intermediate portion between both ends in the X direction of the incident area S1 from the light source 112 enters the area S2 outside the incident area S1. It is difficult to guide.

In the light guide plate 120 shown in FIG. 19, a plurality of holes 113 similar to those of the light guide plate 110 are formed at one side 111 at intervals, so that the holes 113 and the holes in the incident region S1 are formed. The light 122 incident on the portion between the light source 113 and the light 113 travels toward the projection region S3 of the light source 112 of the light guide plate 120 without changing the optical path and in the traveling direction when the light is incident. Therefore, the light 122 incident on the light guide plate 120 between the hole 113 and the hole 113 cannot be guided to the region S2 outside the incident region S1.

On the other hand, in the present embodiment, since the second optical path changing unit 22 is provided at a distance from the first side end surface 11a, there is no difference between the first optical path changing unit 21 and the first optical path changing unit 21. The light incident on the light guide 1 in the meantime can be reflected by the second optical path changing unit 22 and guided to the region S2 outside the incident region S1. The second optical path changing unit 22 is formed at a position avoiding the optical path 31 of the light that has passed through the first optical path changing unit 21, so that the optical path of the light that has passed through the first optical path changing unit 21 It is possible to prevent 31 from being changed by the second optical path changing unit 22. Therefore, in the present embodiment, more light can be guided to the region S2 outside the incident region than the light guide plate 110 shown in FIG. 18 and the light guide plate 120 shown in FIG. The difference in brightness between the area S2 and the area S2 outside the incident area is made smaller, and the brightness S is further reduced by the power S.

FIG. 5 is a diagram illustrating a simulation result of a light guide state of light incident on the light guide 1 according to the first embodiment. FIG. 5 shows the simulation results when one light emitting element 12 is used. In Fig. 5, a light emitting element 12 with a dimension wO of 2.5 mm in the X direction of the light emitting surface 12a shown in Fig. 4 is used, and each dimension m] in Fig. 4 is set to (wl, w2, w3, hi, h2, p ) = (80. 0, 10. 0, 15. 3, 35. 0, 15. 0, 100. 0), and the angle θ 1 between the first optical path changing surface 23 and the reference line L shown in FIG. In this example, the absolute value I Θ 1 is set to 10 °, and the absolute value I Θ 2 I of the angle Θ 2 formed by the second optical path changing surface 24 and the reference line L is set to 45 °. In FIG. 5, each straight line extending radially from the light emitting element 12 indicates the optical path of the light incident on the light guide 1.

From the simulation results shown in FIG. 5, in the light guide 1 of this embodiment, the light emitting element 12 It can be seen that the incident light spreads throughout the first side 11. Therefore, in the present embodiment, as shown in FIG. 5, the luminance difference between the incident region S1 of the first side portion 11 and the region S2 outside the incident region can be reduced, and uneven luminance can be suppressed.

Further, in the light guide 1 of the present embodiment, as shown in FIG. 5, the light incident from the light emitting element 12 spreads to the area S4 outside the projection area S3 of the light emitting element 12 that extends only by the first side portion 11. Yes. Therefore, in the present embodiment, it is possible to suppress uneven brightness over the entire light guide 1.

In the present embodiment, the light guide 1 has the second and third side portions 27 and 28 on both sides in the X direction as reflection portions, so the second and third side portions 27 and 28 on both sides in the X direction. Light incident on 28 can be reflected by the second and third side portions 27 and 28, which are reflection portions, and guided to the inside. For example, out of the light that has passed through the first and second optical path changing units 21 and 22, light incident on the reflecting units 27 and 28 can be reflected and guided to the inside. Therefore, leakage of light from the sides on both sides in the X direction can be prevented, so that the force S for increasing the utilization efficiency of the light incident from the light emitting element 12 can be reduced.

In the present embodiment, the first and second optical path changing portions 21 and 22 are formed by forming holes in the first side portion 11. Therefore, the first and second optical path changing units 21 and 22 can be easily realized.

The lighting device 2 shown in FIG. 3 is configured by including the light guide 1 of the present embodiment described above. The illuminating device 2 includes a plurality of diffusion sheets 13 and 16 and prism sheets 14 and 15 on the emission surface la side of the light guide 1 and in this embodiment, and reflects on the rear lb side of the light guide 1. Seat 17 is provided. A first diffusion sheet 13, a first prism sheet 14, a second prism sheet 15, and a second diffusion sheet 16 are laminated in this order on the emission surface la of the light guide 1.

According to the illumination device 2, light is incident on the first side portion 11 of the light guide 1 from the light emitting element 12, and the incident light is reflected inside the light guide 1 and on each of the sheets 13 to 17. Then, the light is repeatedly bent and emitted to one side Z1 in the Z direction perpendicular to the emission surface la of the light guide 1. Since the light guide 1 includes the first and second optical path changing units 21 and 22, uneven brightness in the first side unit 11 is suppressed. Therefore, a suitable lighting device 2 is realized. Light guide of this embodiment In the lighting device 2 having 1, even if the number of light emitting elements 12 as light sources is reduced and the arrangement interval of the light emitting elements 12 is increased, the difference in luminance between the incident region S1 and the region S2 outside the incident region is reduced. Since it is possible to reduce the brightness unevenness by reducing the number, it is possible to reduce the number of light emitting elements 12 and reduce the cost by IJ.

By using such a lighting device 2 as, for example, a backlight device of a liquid crystal display device, it is possible to easily cope with an increase in the size of the display screen of the liquid crystal display device. A liquid crystal display device capable of displaying is realized. In other words, by using the illumination device 2 including the light guide 1 of the present embodiment, it is possible to realize an increase in the size of the display screen of the liquid crystal display device without degrading the display quality.

In the light guide 1 of the present embodiment described above, the holes formed in the first hole 21 that is the first optical path changing unit and the second hole 22 that is the second optical path changing unit are hollow. A certain force S, the hole is filled with filler 41 as shown in FIG.

FIG. 6 is a plan view showing a part of the light guide 40 in which the holes 41 formed in the first and second optical path changing portions 21 and 22 are filled with the filler 41. The refractive index of the filler 41 is selected to be different from that of the light guide body 25. By changing the refractive index of the filler 41, the refraction angle and critical angle of the light passing through the first and second optical path changing sections 21 and 22 can be adjusted. The force S is used to adjust the optical path of the light that has passed through the second optical path changing units 21 and 22.

In this way, by filling the holes formed in the first and second optical path changing portions 21 and 22 with the filler 41, the optical path of the light that has passed through the first and second optical path changing portions 21 and 22 is filled. The refractive index of the material 41 can be adjusted.

Therefore, the first and second optical path changing units 21 and 22 can be realized, which can more reliably guide more light incident on the incident region S 1 to the region S 2 outside the incident region of the first side portion 11. The power to do S. As a result, the difference in luminance between the incident region S 1 of the first side portion 11 of the light guide 1 and the region S2 other than the incident region S 1 can be further reduced, and uneven luminance can be more reliably suppressed. Touch with force S.

Further, in the light guide 1 of the present embodiment, a plurality of, more specifically two, first optical path changing sections 21 are formed. The plurality of first optical path changing units 21 have the same shape in this embodiment. A certain force S, not limited to this, may be different shapes. When three or more first optical path changing portions 21 are formed, the arrangement interval P in the X direction may be equal or different.

In the light guide 1 of the present embodiment, a plurality of, more specifically, two second optical path changing units 22 are formed. The plurality of second optical path changing units 22 is not limited to the force S having the same shape in the present embodiment, and may have different shapes. When three or more second optical path changing units 22 are formed, the arrangement interval p in the X direction may be an equal interval or may be different.

Further, the opening shape in the XY plane perpendicular to the thickness direction Z of the hole that realizes the first and second optical path changing portions 21 and 22 is not limited to the trapezoidal shape, and may be another polygonal shape such as a triangular shape. The shape may include a curved surface.

FIG. 7 is a plan view showing a part of the light guide 50 according to the second embodiment of the present invention. In the light guide 50 of the present embodiment, the other configurations except for the first and second optical path changing units 2 1 and 22 in the first embodiment are the same, and thus the same reference numerals are used for the same configurations. The explanation is omitted.

In the present embodiment, the second optical path changing unit 52 is spaced from the first side end surface 11a, which is the end surface of the first side unit 11, in the same manner as the second optical path changing unit 22 in the first embodiment. In addition, it is formed at a position that avoids the optical path 57b of the light that has passed through the first optical path changing unit 51. Further, the first and second optical path changing units 51 and 52 are provided with holes in the first side portion 11 of the light guide 50, similarly to the first and second optical path changing units 21 and 22 in the first embodiment. More specifically, it is formed by forming a through hole. Also in this embodiment, the holes formed in the first and second optical path changing portions 5 1 and 52 are formed in a row.

The hole formed in the first hole 51 that is the first optical path changing unit is the same as the hole formed in the first hole 21 that is the first optical path changing unit in the first embodiment in the Z direction. The trapezoid is arranged in the XY plane perpendicular to the Z direction, and more specifically, the upper and lower bases are parallel to the first side end face 11a and the first side end face is higher than the upper base. It is a columnar shape with an isosceles trapezoid with a long bottom bottom arranged on the 11a side and extending in the Z direction. The first optical path changing unit 51 includes two planar optical path changing surfaces 53, that is, the first first optical path changing surface 53a and the second first optical path changing surface. A further surface 53b is formed.

The second hole portion 52, which is the second optical path changing portion, is continuous with the hole of the first hole portion 51, and the opening shape in the XY plane perpendicular to the Z direction that is the thickness direction of the light guide 50 is triangular. A hole is formed. The hole of the second hole 52 has a uniform shape in the Z direction, and is a triangle arranged in the XY plane perpendicular to the Z direction, more specifically, the base is parallel to the first side end surface 11a and is a vertex. Is a triangular prism shape in which the isosceles triangles arranged in the Y direction other than the bottom side on the other side Y2 side, that is, on the side opposite to the first side end face 1 la, extend in the Z direction.

The second optical path changing unit 52 includes four planar second optical path changing surfaces 54, 55, that is, a first second optical path changing surface 54a, a second second optical path changing surface 54b, and a third second optical path changing surface. An optical path changing surface 55a and a fourth second optical path changing surface 55b are formed. The plane formed by extending the hypotenuse of the triangle arranged in the XY plane perpendicular to the Z direction in the Z direction corresponds to the first and second second optical path changing surfaces 54a and 54b, and the base is in the Z direction. The ends on both sides in the X direction of the plane formed to extend to correspond to the third and fourth second optical path changing surfaces 55a and 55b.

The first and second second optical path changing surfaces 54a and 54b are planes inclined from a virtual plane parallel to the first side end surface 11a that is the end surface of the first side portion 11, and from the first side end surface 11a. Accordingly, the opening area in a virtual plane parallel to the first side end face 11a of the hole of the second hole portion 52 is reduced. The first second optical path changing surface 54a is formed closer to the XI side in the X direction than the second second optical path changing surface 54b. The first second optical path changing surface 54a is formed so as to incline from the imaginary plane perpendicular to the first side end surface 11a toward the other side X2 in the X direction as the distance from the first side end surface 11a increases. The second second optical path changing surface 54b is formed so as to incline from the imaginary plane perpendicular to the first side end surface 11a toward the XI side in the X direction as the distance from the first side end surface 11a increases.

Therefore, the light that is directly incident on the second optical path changing unit 52 from the light emitting element 12 is transmitted to the first optical path changing unit 51 from the light emitting element 12 on the first and second second optical path changing surfaces 54a and 54b. Similar to the directly incident light 56a, the light is refracted so that the absolute value of the angle formed with the reference line perpendicular to the end surface 11a of the first side portion 11 is increased.

Thus, the second optical path changing unit 52 is positive (+) on the other X2 side in the X direction from the reference line L perpendicular to the first side end surface 11a, and negative (one) on the XI side in the X direction. Directly from light emitting element 12 The absolute value of the angle γ 2 formed between the optical path 57 of the light that has been incident and passed through the second optical path changing unit 52 and the reference line L | _γ 2 | force S, from the light emitting element 12 to the second optical path changing unit 52 The incident light is refracted to be larger than the absolute value I γ γ I of the angle γ 1 formed by the optical path 56 of the light incident on the reference line L. In other words, the light incident on the first and second second optical path changing surfaces 54a and 54b is refracted by the first and second second optical path changing surfaces 54a and 54b so as to be bent in the Y direction side Y1 side. Thus, in the region S4 outside the projection region of the light emitting element 12 of the light guide 50, the light is guided to the portion on the other side Y2 in the Y direction from the first side portion 11 that is the region S2 outside the incident region.

In the present embodiment, the first optical path changing surface 53 and the second optical path changing surface 54 are positive (+) on the other side in the X direction from the reference line L perpendicular to the first side end surface 11a, and negative on the one side in the X direction. In (1), the angle between the second optical path change surface 54 and the reference line L. The absolute value of Θ 2 I Θ 2 I force S, the angle between the first optical path change surface 53 and the reference line L θ It is formed so as to be larger than the absolute value I Θ 1 I of 1.

FIG. 8 is a view for explaining the light refraction state on the third and fourth second optical path changing surfaces 55a and 55b of the second optical path changing section 52. FIG. The third and fourth second optical path changing surfaces 55a and 55b are formed in parallel to the first side end surface 11a. The light incident on the third and fourth second optical path changing surfaces 55a and 55b is guided to the region S2 outside the incident region through two refractions as shown in FIG. More specifically, the light incident on the third and fourth second optical path changing surfaces 55a and 55b is bent at the third and fourth second optical path changing surfaces 55a and 55b in the Y direction and on the Y1 side. The light is bent and emitted, and the emitted light enters the first or second second optical path changing surfaces 54a and 54b, and is further refracted and bent so as to be bent in the Y direction on the Y1 side. Guided to area S 2 outside the area.

In this way, the second optical path changing unit 52 is incident on the light that has entered from the light emitting element 12 through a part other than the second optical path changing unit 52 of the first side part 11 and has passed through the second optical path changing unit 52. The absolute value of the angle γ 4 formed by the optical path 59 and the reference line L I γ 4 I force S, the optical path 5 8 of the light incident from the light emitting element 12 The absolute value of the angle γ 3 formed by the reference line L I γ 3 Refracts incident light so that it is larger than I.

The dimensions and arrangement intervals of the first and second optical path changing sections 51 and 52 are the same as those of the first and second optical path changing sections 21 and 22 in the first embodiment. The light emitting surface 12a of a certain light emitting element 12 is selected according to the dimension wO in the X direction.

For example, when the dimension wO in the X direction of the light emitting surface 12a of the light emitting element 12 is about 2.5 mm, the maximum dimension wl ′ in the X direction of the second optical path changing unit 52 is selected as 66.7 111. The dimension _W 2 'in the X direction of the opening end of the connecting portion 44 between the first optical path changing section 51 and the second optical path changing section 52 is selected as 27.2 111, and the X of the first optical path changing section 51 The maximum dimension w3 'in the direction is chosen to be 35.Om, the dimension h1' in the Y direction of the second optical path changing part 52 is chosen to be 33.4 111, and the first optical path changing part 51 in the Y direction The dimension h2 ′ is selected to be 22.011 m, and the arrangement interval p of the first optical path changing unit 51 and the arrangement interval P ′ of the second optical path changing unit 52 are each selected to be 90 · 0 m. The dimensions and arrangement intervals of the first and second optical path changing sections 51 and 52 are not limited to the above values! /.

In the present embodiment, the maximum dimension wl ′ in the X direction of the second optical path changing unit 52 is equal to that of the fourth second optical path changing surface 55b from the X direction end XI side of the third second optical path changing surface 55a. X direction The dimension in the X direction of the portion extending on the other X2 side, and the maximum dimension w3 ′ in the X direction of the first optical path changing unit 51 is the first dimension of the first hole 51 that is the first optical path changing unit. It is the dimension in the X direction of the opening end on the side end face 1 la side.

As described above, since the light guide 50 of the present embodiment includes the first and second optical path changing units 51 and 52, the first light among the light incident on the incident region S1 from the light emitting element 12 is the first. The light directly incident on the optical path changing unit 51 is refracted by the first optical path changing unit 51 and guided to the region S2 outside the incident region S1 of the first side part 11 and incident on the second optical path changing unit 52. The incident light can be refracted by the second optical path changing unit 52 and guided to the region S2 outside the incident region S1 of the first side portion 11. Therefore, the luminance difference between the incident region S1 of the first side portion 11 and the region S2 outside the incident region can be reduced, and uneven luminance can be suppressed.

Further, the second optical path changing unit 51 refracts the light incident on the first and second second optical path changing surfaces 54a and 54b so as to be bent in the Y direction side Y1 side, thereby projecting the projection region of the light emitting element 12. Lead to outside area S4. Therefore, in the light guide 50 according to the present embodiment, the light that travels in the traveling direction at the time of incident light out of the light incident from the light emitting element 12 as compared with the light guide plate 120 shown in FIG. 19 described above. Can be reduced.

The hole 113 shown in FIG. 19 and the first and second optical path changing parts 51 and 52 shown in FIG. Assuming that the spacing is equal to each other, the light that travels without changing the traveling direction out of the light that enters the hole 113 shown in FIG. The light is incident on a region (S5 + S6) obtained by adding S5 and the region S6 indicated by the slanting line to the right.

On the other hand, in the present embodiment, the light incident on the region S5 is guided to the region S4 outside the projection region by the first and second second optical path changing surfaces 54a and 54b, so the traveling direction is not changed. The light traveling to is only the light incident on the region S6. Therefore, in the present embodiment, more light can be guided to the region S4 outside the projection region than the light guide plate 120 shown in FIG.

A region S5 illustrated in FIG. 8 is a remaining region excluding the projection regions of the third and fourth second optical path changing surfaces 55a and 55b, among the projection regions of the second optical path changing unit 52. The region S6 is a partial projection region in which the first and second optical path changing portions 51 and 52 of the first side portion 11 are also! / And misaligned.

FIG. 9 is a diagram illustrating a simulation result of a light guide state of light incident on the light guide 50 according to the second embodiment. FIG. 9 shows the simulation results when one light emitting element 12 is used. In Fig. 9, a light emitting element 12 with a dimension wO in the X direction of the light emitting surface 12a shown in Fig. 8 of 2.5 mm is used, and each dimension m] in Fig. 8 is set to (wl ', w2', w3 ', hi' , h2 ', ρ') = (66. 7, 27. 2, 35. 0, 33. 4, 22. 0, 90. 0), the first optical path changing surface 5 3 and reference line L shown in Fig. 7 The absolute value of the angle θ1 I θ 1 I is 10 °, and the angle between the first and second optical path change surfaces 54a, 54b and the reference line L is the absolute value of Θ 2 | Θ 2 | In this case, the angle is 45 °. In FIG. 9, each straight line extending radially from the light emitting element 12 indicates the optical path of the light incident on the light guide 50. From the simulation result shown in FIG. 9, in the light guide 50 of the present embodiment, the incident region S1 of the first side portion 11 and the incident light are compared with the light guide plate 110 shown in FIG. 18 and the light guide plate 120 shown in FIG. It can be seen that the luminance difference with the region S2 outside the region can be made smaller, and the luminance unevenness can be further suppressed.

FIG. 10 is a plan view showing a part of the light guide 60 according to the third embodiment of the present invention. In the light guide 60 of the present embodiment, the other configurations except for the first and second optical path changing units 21 and 22 in the first embodiment are the same, and thus the same reference numerals are used for the same configurations. The description is omitted.

In the present embodiment, the first and second optical path changing units 61 and 62 are arranged on the first side of the light guide 60 in the same manner as the first and second optical path changing units 21 and 22 in the first embodiment. It is formed by forming a hole in the part 11, more specifically, a through hole. In the present embodiment, the holes formed in the first and second optical path changing portions 61, 62 are not continuous and are formed separately in the first hole portion 61, which is the first optical path changing portion, A hole having a triangular opening in the XY plane, which is a virtual plane perpendicular to the Z direction, which is the thickness direction of the light guide 60, is formed. The hole of the first hole 61 has a uniform shape in the Z direction and is a triangle arranged on the XY plane perpendicular to the Z direction, more specifically, the base is parallel to the first side end surface 11a and the apex. Is a triangular prism shape in which an isosceles triangle arranged in the Y direction on the other side in the Y direction from the bottom side, that is, on the side opposite to the first side end face 1 la, extends in the Z direction.

In the first optical path changing unit 61, two planar first optical path changing surfaces 63, that is, a first first optical path changing surface 63a and a second first optical path changing surface 63b are formed. The first and second first optical path changing surfaces 63a and 63b are formed in the same manner as the first and second first optical path changing surfaces 23a and 23b in the first embodiment.

In the second hole portion 62 that is the second optical path changing portion, a hole having a triangular opening shape in the XY plane perpendicular to the Z direction that is the thickness direction of the light guide 60 is formed. The hole of the second hole 62 has a uniform shape in the Z direction and is a triangle arranged in the XY plane perpendicular to the Z direction. More specifically, the base is parallel to the first side end face 11a and the apex is It is a triangular prism shape that extends in the Z direction from an isosceles triangle that is arranged on the one side Y1 in the Y direction from the bottom side, that is, on the first side end face 11a side.

In the second optical path changing unit 62, two planar second optical path changing surfaces 64, that is, a first second optical path changing surface 64a and a second second optical path changing surface 64b are formed. The first and second second optical path changing surfaces 64a and 64b are formed in the same manner as the first and second second optical path changing surfaces 24a and 24b in the first embodiment.

In the present embodiment, the holes forming the first and second optical path changing units 61 and 62 are formed separately, and the first and second optical path changing units 61 and 62 are provided separately. like this By separately providing the first and second optical path changing units 61 and 62, the first and second optical path changing units 61 and 62 can be realized in a simple shape. Accordingly, the light guide 60 can be easily manufactured.

Also in the present embodiment, the second optical path changing unit 62 is formed at a position that is spaced from the end surface 11a of the first side part 11 and avoids the optical path of the light that has passed through the first optical path changing unit 61. . In the present embodiment, the second optical path changing unit 62 includes the center line in the X direction of the second optical path changing unit 62 in the virtual plane including the center line in the X direction of the first optical path changing unit 61. When arranged in such a manner, a part of the second optical path changing unit 62 is formed so as to overlap a part of the first optical path changing unit 61.

FIG. 11 is a plan view showing a part of the light guide 70 according to the fourth embodiment of the present invention. In the light guide 70 of the present embodiment, the configuration other than the second optical path changing unit 62 in the third embodiment shown in FIG. 10 is the same, and thus the same configuration is denoted by the same reference numeral. The description is omitted.

In the present embodiment, the second optical path changing unit 71 is the same inner wall of the hole as the second optical path changing unit 62 in the third embodiment, that is, the first and second second optical path changing surfaces 64a, 64b. A reflective layer 72; The reflective layer 72 is formed so as to have a reflectance of approximately 1.0 with respect to incident light, as with the reflective layer 26 in the first embodiment.

Thus, by forming the reflective layer 72 on the inner wall of the hole formed in the second optical path changing section 71, the light incident on the first and second second optical path changing surfaces 64a and 64b from almost all directions can be substantially reduced. All can be reflected. Accordingly, since the second light path changing unit 71 can guide more light to the incident region S1 of the first side portion 11, the space between the incident region S1 of the first side portion 11 and the region S2 outside the incident region can be reduced. The difference in brightness between the two is reduced, and the unevenness in brightness is further suppressed with the force S.

FIG. 12 is a plan view showing a part of the light guide body 75 according to the fifth embodiment of the present invention. In the light guide 75 of the present embodiment, the other configurations except for the second optical path changing unit 62 in the third embodiment shown in FIG. 10 are the same, and thus the same configurations are denoted by the same reference numerals. The description is omitted.

In the present embodiment, the second optical path changing unit 76 is the second light in the third embodiment. Similarly to the path changing unit 62, the first side portion 11 of the light guide 75 is formed by forming a hole, more specifically, a through hole.

In the second hole portion 76 that is the second optical path changing portion, a hole having a triangular opening shape in the XY plane perpendicular to the Z direction that is the thickness direction of the light guide 75 is formed. The hole of the second hole 76 has a uniform shape in the Z direction, and is a triangle arranged in the XY plane perpendicular to the Z direction. More specifically, the base is parallel to the first side end face 11a and the apex is This is a triangular columnar shape in which an isosceles triangle arranged in the Y direction on the other side in the Y direction from the bottom side, that is, on the side opposite to the first side end face 11a, extends in the Z direction.

In the second optical path changing unit 76, two planar second optical path changing surfaces 77, that is, a first second optical path changing surface 77a and a second second optical path changing surface 77b are formed. The first and second second optical path changing surfaces 77a and 77b are formed in the same manner as the first and second second optical path changing surfaces 54a and 54b in the second embodiment shown in FIG.

In the present embodiment, as in the third embodiment, the holes forming the first and second optical path changing units 61 and 76 are formed separately, and the first and second optical path changing units 61 and 76 are formed. Are provided separately. Therefore, since the first and second optical path changing sections 61 and 76 can be realized with a simple shape, the light guide 75 can be easily manufactured.

Also in the present embodiment, the second optical path changing unit 76 is formed at a position that is spaced from the end surface 11a of the first side part 11 and avoids the optical path of the light that has passed through the first optical path changing unit 61. . In the present embodiment, the second optical path changing unit 76 includes the center line in the X direction of the second optical path changing unit 76 in the virtual plane including the center line in the X direction of the first optical path changing unit 61. When arranged in such a manner, a part of the second optical path changing unit 76 is formed so as to overlap a part of the first optical path changing unit 61.

FIG. 13 is a plan view showing a light guide body 80 according to the sixth embodiment of the present invention. The light guide 80 according to the first embodiment shown in FIG. 2 is the same as the light guide 80 according to the first embodiment shown in FIG. Therefore, the same reference numerals are assigned to the same components and the description thereof is omitted.

The light guide 80 according to the present embodiment includes an emission preventing portion 81 on the other side portions except the first side portion 11, more specifically on the second and third side portions 27 and 28 on both sides in the X direction. Have Output prevention part 8 1 is formed by forming the end surfaces of the side portions 27 and 28 on both sides in the X direction, which are end surfaces of the other side portions, into curved surfaces convex outward.

As described above, the light guide body 80 of the present embodiment has the emission preventing portions 81 on the side portions 27 and 28 on both sides in the X direction, which are the other side portions except the first side portion 11, and therefore enters from the light emitting element 12. It is possible to prevent the emitted light from being emitted to the outside. Therefore, the utilization efficiency of the light incident from the light emitting element 12 can be increased.

Further, in the present embodiment, the emission preventing portion 81 is formed by forming the end surfaces of the side portions 27 and 28 on both sides in the X direction to have outwardly convex curved surfaces. It can prevent more reliably that light is radiate | emitted outside.

The emission preventing portion is not limited to the configuration formed by forming the end surface into a curved surface convex outward as in the emission preventing portion 81 shown in FIG. For example, like the emission preventing portion 86 shown in FIG. 14, it may be formed by forming notches in other side portions except the first side portion 11, for example, the side portions 27 and 28 on both sides in the X direction. . FIG. 14 is a plan view showing a light guide 85 having an emission preventing portion 86 formed by forming a notch in the side portion. As shown in FIG. 14, the emission preventing portion 86 can be easily realized by forming the emission preventing portion 86 by forming a notch in the side portion.

By having such emission preventing portions 81 and 86, the light use efficiency can be improved even if the side layer cannot be provided with a reflective layer for some reason, for example, cost reduction or manufacturing. There is an effect.

FIG. 15 is a plan view showing a light guide 90 according to the seventh embodiment of the present invention. The light guide 90 of the present embodiment has the same configuration as the light guide 1 of the first embodiment shown in FIG. 2 except that the two main surfaces 90a and 90b are formed in a rough surface shape. Therefore, the same reference numerals are given to the same components, and the description will be omitted.

In the light guide 90 of the present embodiment, at least one of the main surfaces 90a and 90b which are the surfaces on both sides in the thickness direction Z, in the present embodiment, both main surfaces 90a and 90b are roughened. Is formed. Of these two main surfaces 90a and 90b, the main surface 90a on the Z1 side in the Z direction is the emission surface, and the main surface 90b on the other side in the Z direction is the back surface.

Thus, in this embodiment, the exit surface 90a and the back surface 90b, which are the main surfaces, are formed into rough surfaces. Therefore, the light incident on the exit surface 90a and the back surface 90b can be diffused. As a result, it is possible to suppress uneven brightness on the exit surface 90a.

In the present embodiment, a dot-shaped recess 91 is formed on the entire surface of the light guide 90 where the main surfaces 90a and 90b are formed. By forming the recess 91 in the surface portion in this manner, the main surfaces 90a and 90b are formed in a rough surface shape. The rough main surfaces 90a and 90b are not limited to this, and may be formed by forming convex portions on the surface portion, for example. The shape of the concave portion 91 and the convex portion formed on the surface portion is not limited to a dot shape, and may be a grain shape, for example. The rough main surfaces 90a and 90b may be formed by forming grooves on the surface portion. The cross-sectional shape of the groove is, for example, V-shaped or cylindrical.

The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects, and the scope of the present invention is shown in the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the scope of claims are within the scope of the present invention.

Industrial applicability

According to the present invention, the light guide has, on one side, an incident region that is provided to face the light source, and has a first optical path changing unit and a second optical path changing unit in the incident region, Light incident from one side is diffused and emitted from at least one main surface. Light from the light source is directly incident on the first optical path changing unit, and the absolute value of the angle formed by the first optical path changing unit and the reference line perpendicular to the end surface of one side is large. Refracted to be. The second optical path changing unit is formed at a position that is spaced from the end face of one side and avoids the optical path of the light that has passed through the first optical path changing unit. It is reflected or refracted so that the absolute value of the angle formed with the reference line perpendicular to the end face of the surface becomes large. As a result, of the light incident on the incident area from the light source, the light that is directly incident on the first optical path changing section is refracted by the first optical path changing section, and the area outside the incident area on one side portion. In addition, the light incident on the second optical path changing unit can be reflected or refracted by the second optical path changing unit and guided to an area outside the incident area on one side. Therefore, the incident area on one side and It is possible to realize a light guide body that can reduce the difference in luminance from the region outside the incident region and suppress uneven luminance.

According to the present invention, since at least one of the first and second optical path changing portions is formed by forming a hole in one side portion, it can be easily realized. According to the present invention, since the hole that realizes at least one of the first and second optical path changing portions is filled with the filler, the light passing through the optical path changing portion is filled. The refraction angle and critical angle can be adjusted by the refractive index of the filler. Therefore, since the optical path of the light that has passed through the optical path changing portion can be adjusted by the refractive index of the filler, it is possible to reliably guide the light incident on the incident region to a region outside the incident region on one side. A possible optical path changing unit can be realized. As a result, the difference in luminance between the incident region on one side of the light guide and the region other than the incident region can be reduced more reliably, and thus uneven luminance can be more reliably suppressed. it can.

According to the present invention, the light guide has the emission preventing portion on the other side portion except the one side portion. As a result, it is possible to prevent the light incident from the light source from being emitted to the outside, so that the utilization efficiency of the light incident from the light source can be increased.

According to the present invention, the emission preventing portion is formed by forming the end surface of the other side portion into a curved surface that is convex outward. As a result, it is possible to more reliably prevent light incident from the light source from being emitted to the outside.

According to the present invention, since the emission preventing portion is formed by forming a notch on the other side portion, it can be easily realized.

According to the present invention, since at least one of the main surfaces is formed into a rough surface, light incident on the main surface can be diffused. As a result, it is possible to suppress uneven brightness on the main surface that emits light incident from one side.

According to the present invention, the light guide has the reflecting portion that reflects the incident light on the other surface portion except the surface portion on which the main surface that emits the light incident from one side portion is formed. As a result, the light incident on the other surface portion can be reflected by the reflecting portion and guided to the inside, so that the utilization efficiency of the light incident from the light source can be increased.

According to the present invention, an illuminating device is realized including the above-described excellent light guide and light source. The Thereby, a suitable illumination device is realized.

Claims

The scope of the claims

[1] A light guide that diffuses and emits incident light,

One side where light is incident;

Including at least one main surface that emits diffused light,

In the incident area,

A first optical path changing unit that directly irradiates light from a light source and refracts the incident light so that an absolute value of an angle formed with a reference line perpendicular to an end surface of one side is increased; Is formed at a position that is spaced from the end face of the light source and avoids the light path of the light that has passed through the first light path changing section, and allows light incident from the light source to And a second optical path changing unit that reflects or refracts so that the absolute value of the angle formed becomes large.

[2] The light guide according to claim 1, wherein at least one of the first and second optical path changing portions is formed by forming a hole in one side portion.

[3] The light guide according to claim 2, wherein the hole is filled with a filler.

[4] The force according to any one of claims 1 to 3, wherein the other side portion excluding the one side portion has an emission preventing portion for preventing light incident from the light source from being emitted to the outside. The light guide described in 1.

[5] The light guide according to claim 4, wherein the emission preventing portion is formed by forming an end surface of the other side portion into a curved surface that is convex outward.

6. The light guide according to claim 4, wherein the emission preventing part is formed by forming a notch on the other side part.

[7] The light guide according to any one of [1] to [6], wherein at least one main surface is formed into a rough surface.

[8] The other surface portion excluding the surface portion on which the main surface that emits light incident from one side portion is formed has a reflecting portion that reflects incident light. 7. The light guide according to any one of 7, the power.

[9] The force according to any one of claims 1 to 8, wherein the light guide body according to one and the incident area of the light guide body are opposed to each other. And a light source that makes light incident on the incident area.