JP2003086015A - Light guiding body and plane surface lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make light from a light source enter a light guiding plate as much as possible and make light beam emit from an optional part of an emission surface of the light guiding plate at designated optional emission angles. SOLUTION: The light guiding body 2 includes a surface part 3 emitting light from a light source 20, a back surface part 6 on an opposite side of the surface part 3, and a side surface part 4 put between the surface part 3 and the back surface part 6. An entrance end surface part 5 guiding light from the light source 20 is smaller than the surface part 3, the back surface part 6 and the side surface part 4. The side surface part 3 is twisted wholly or partially. Fine projection and dent shapes, prisms and fine grooves or the like are selectively wholly or partially provided on the surfaces except the entrance end surface part 5 and surface part 3. A reflector 7 reflects light leaking from the light guiding body 2 to the light guiding body 2 and a light guiding plate 9. The light guiding plate 9 is comprised of an entrance surface part 12 guiding emission light form the light guiding body 2, a surface part 10 having larger area than the entrance surface part 12 and emitting light form the entrance surface part 12, and a back surface part 11 on an opposite side of the surface part 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide and a planar illuminating device, and at least from an incident end face portion smaller than a side face portion sandwiched between a front face portion and a rear face portion of a light guide member from a light source. The surface of which the light is emitted and which emits light, the back surface or the plane provided in the longitudinal direction of the cylinder is twisted wholly or partially, or a large number of fine surfaces are formed on the back surface. It has an inclination with respect to the surface and changes the inclination as it gets closer to the incident end face, and changes the emission angle of the ray vertically with respect to the virtual horizontal line at any position on the surface that emits the ray. By providing this light guide on the side surface of the light guide plate as an incident part,
The present invention relates to a light guide body and a flat lighting device that allow light from a light source to be incident on the light guide plate as much as possible and to be emitted from an arbitrary position on the light guide plate.

[0002]

2. Description of the Related Art A conventional flat lighting device is provided with a linear light source on a side surface of a light guide plate and utilizes reflection or refraction by an uneven shape or a narrow groove on a front surface or a back surface of the light guide plate. A method is known in which light guided from a light source is emitted from a side surface portion through a surface portion or the like.

Further, in a conventional flat lighting device using a point light source such as an LED as a light source, a plurality of LEDs are arranged on a side surface of a light guide plate, and the light is emitted from an emission surface of the light guide plate facing the LEDs. There are known methods for projecting the required light beam.

[0004]

A conventional flat lighting device is provided with a linear light source on a side surface of a light guide plate, and is provided with an uneven shape or a narrow groove on a front surface or a back surface of the light guide plate to prevent reflection or refraction. In the method in which the light guided from the light source is emitted from the side surface part through the surface part, etc., the light rays entering the incident end surface part of the light guide plate are all the same linearly as the parameter depends on the light guide plate. Since the output angles are the same and the light energies at the same output angle are the same, the light rays that enter the light guide plate can only be deflected by reflection or refraction due to the uneven shape or narrow grooves provided on the front or back surface of the light guide plate. There are issues that cannot be solved.

Further, in a conventional flat lighting device using a point light source such as an LED as a light source, a plurality of LEDs are arranged on a side surface of a light guide plate, and light is emitted from an emission surface of the light guide plate facing the LEDs. In the method of projecting the required light beam, the emission energy and light beam intensity distribution of each LED are not constant, and the emission energy and light beam intensity distribution of the LED are not constant with respect to the incident end face of the light guide plate. , LE even if the emitting angle of the LED is changed with respect to the incident end surface of the light guide plate
The energy distribution is circular or elliptical because the light source is a point light source because it depends on the size of D, and the light rays that enter the light guide plate are emitted from the front surface and the back surface. There are issues that cannot be controlled.

The present invention has been made to solve such a problem, and its purpose is at least a side surface where an incident end face portion for guiding light from one light source is sandwiched between a front surface portion and a back surface portion of a light guide. Smaller than the area, and the surface or back surface that emits light or the plane provided in the longitudinal direction of the cylinder can be twisted wholly or partially, or a large number of fine surfaces are formed on the back surface, The surface has an inclination with respect to the surface part,
Further, by changing the inclination toward the incident end face portion, it is possible to change the emission angle of the light beam in the vertical direction with respect to the virtual horizontal line depending on the position of the surface portion that emits the light beam.
By providing this light guide on the side surface of the light guide plate as an incident part, the light from the light source is made to enter the light guide plate to the maximum extent, and at an emission angle specified from any position on the emission surface of the light guide plate. An object of the present invention is to provide a light guide and a flat lighting device that can emit light rays.

[0007]

In order to solve the above-mentioned problems, a light guide according to a first aspect of the present invention has an incident end face portion smaller than a front surface portion, a back surface portion and a side surface portion, and the front surface portion wholly or partially. It is characterized in that the emitted light is totally or partially changed.

In the light guide according to the first aspect, the incident end face portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the front surface portion is wholly or partially twisted so that the outgoing light is wholly or partially. Since it is changed, the emission angle of the emitted light can be changed at any position on the surface portion.

Further, in the light guide according to the second aspect, the incident end face portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the back surface portion is wholly or partially twisted so that the outgoing light is wholly or partially. The feature is that it is changed dynamically.

In the light guide according to the second aspect, the incident end face portion is smaller than the front surface portion, the rear surface portion and the side surface portion, and the rear surface portion is wholly or partially twisted so that the emitted light is wholly or partially. Since it is changed, the emission angle of the emitted light can be changed at any position on the surface portion.

Further, in the light guide according to claim 3, the incident end face portion is smaller than the front surface portion, the rear surface portion and the side surface portion, and the front surface portion and the rear surface portion have the same twisting direction and twisting angle as a whole or a part. It is characterized in that the emitted light is totally or partially changed.

In the light guide according to claim 3, the incident end face is smaller than the front face part, the back face part and the side face part, and the front face part and the back face part have the same twist direction and twist angle, wholly or partially. Since the twisting and the outgoing light are changed wholly or partially, the outgoing angle of the outgoing light can be changed at an arbitrary position on the front surface portion, compared to the case where only one of the front surface portion and the back surface portion is twisted. The deflection angle of light can be increased.

The light guide according to a fourth aspect is characterized in that it has a cylindrical shape, and the emission surface portion is a flat surface twisted in the longitudinal direction of the cylindrical shape.

According to the fourth aspect of the present invention, since the light guide has a cylindrical shape, and the emission surface portion is a flat surface twisted in the longitudinal direction of the cylinder, there is little leakage light and the emission angle from the emission surface portion can be arbitrarily changed. You can

Further, in the light guide according to a fifth aspect, fine convex and concave shapes, prisms, fine grooves, and the like are selectively provided all or partly in addition to the incident end surface portion and the surface portion or the output surface portion. It is characterized by

In the light guide according to the present invention, fine convex or concave shapes, prisms, fine grooves, etc. are selectively provided all over or partially in addition to the incident end face and the surface or the exit face. The light beam guided from the incident end face portion is selectively reflected and guided toward the surface portion so as to be emitted from the surface portion.

According to a sixth aspect of the present invention, the light guide body has a surface which is substantially vertical to the virtual horizontal plane, has a curved surface in the horizontal direction, and has a wedge shape with respect to the virtual horizontal plane, and totally reflects in the direction of the surface portion or the emission surface portion. It is characterized in that a fine convex shaped portion is provided on a portion other than the incident end surface portion and the surface portion or the emission surface portion.

According to a sixth aspect of the present invention, in a light guide body, a surface which is formed substantially perpendicular to a virtual horizontal plane has a curved surface in the horizontal direction and has a wedge shape with respect to the virtual horizontal plane, and the light is reflected in the direction of the surface portion or the emission surface portion. Since such a convex portion is provided on a portion other than the incident end surface portion and the surface portion or the emission surface portion, it is possible to guide light having directivity to the surface portion or the emission surface portion.

Further, in the light guide according to claim 7, the incident end face portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the back surface portion has a large number of boundaries in the direction of both side surfaces and is surrounded by the boundaries. It is characterized in that it is composed of a large number of fine surfaces, and each fine surface has an inclination with respect to the surface portion, and the inclination becomes smaller or larger as it approaches the incident end surface portion.

According to a seventh aspect of the present invention, in the light guide body, the incident end surface portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the back surface portion has a large number of boundaries in the direction of both side surfaces and is surrounded by a large number of boundaries. It is composed of minute surfaces, and each minute surface has an inclination with respect to the surface part, and the inclination becomes smaller or larger as it approaches the incident end surface part, so by setting the inclination of any minute surface surrounded by individual boundaries. It is possible to obtain outgoing light having an arbitrary outgoing angle.

In the flat illumination device according to the eighth aspect, the light source, the front surface portion for emitting the light from the light source, the back surface portion opposite to the front surface portion, and the front surface portion and the back surface portion are sandwiched. The incident end face that guides the light from the light source is smaller than the front face, the back face, and the side face, and the front face is wholly or partially twisted. A light guide body in which minute convex or concave shapes, prisms, minute grooves, etc. are selectively provided on the entire surface or partially,
An incident surface portion that guides the light emitted from the light guide, a light guide plate that has a surface area that is larger than the incident surface portion and that emits light from the incident surface portion, and a light guide plate that is a back surface opposite to the front surface. It is characterized by comprising a light guide and a reflector for reflecting light leaking from the optical body to the light guide and the light guide plate.

A flat illumination device according to claim 8 includes a light source,
An incident end face portion that guides light from the light source has a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion that is sandwiched between the front surface portion and the back surface portion. Smaller than the front surface, back surface, and side surfaces, and the surface is twisted wholly or partially, and in addition to the incident end surface and the output surface, fine convex and concave shapes, prisms, and fine grooves are selectively over the entire surface. Or a partially provided light guide, an incident surface portion that guides the light emitted from the light guide, and a surface that has a larger area than this incident surface portion and that emits light from the incident surface portion,
Since a light guide plate consisting of this surface and a back surface opposite to this surface and a reflector for reflecting the leaked light from the light guide body to the light guide body and the light guide plate are provided, the light beam from the light source is reflected on the surface portion of the light guide body. Change the output angle of the output light at any position,
Since the light is guided to the incident end face portion of the light guide plate, the specified light beam can be emitted from any position of the light guide plate.

Further, the flat illumination device according to claim 9 is
The light source, a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, and guides light from the light source. The end face is smaller than the front face, the back face and the side face, and the back face is wholly or partially twisted, and fine convex and concave shapes other than the incident end face and the output face, prisms and fine grooves are selected. A light guide body that is entirely or partially provided, an incident surface portion that guides light emitted from the light guide body, and a surface that has a larger area than the incident surface portion and that emits light from the incident surface portion. It is characterized by comprising a light guide plate composed of a front surface and a back surface opposite to the front surface, and a reflector for reflecting light leaked from the light guide body to the light guide body and the light guide plate.

A flat illumination device according to claim 9 includes a light source,
An incident end face portion that guides light from the light source has a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion that is sandwiched between the front surface portion and the back surface portion. It is smaller than the front, back, and side surfaces, and the back is twisted in whole or in part, and in addition to the incident end surface and the exit surface, fine convex and concave shapes, prisms, and fine grooves are selectively over the entire surface. Or a partially provided light guide, an incident surface portion that guides the light emitted from the light guide, and a surface that has a larger area than this incident surface portion and that emits light from the incident surface portion,
Since a light guide plate consisting of this surface and a back surface opposite to this surface and a reflector for reflecting the leaked light from the light guide body to the light guide body and the light guide plate are provided, the light beam from the light source is reflected on the surface portion of the light guide body. Change the output angle of the output light at any position,
Since the light is guided to the incident end face portion of the light guide plate, the specified light beam can be emitted from any position of the light guide plate.

A flat lighting device according to a tenth aspect of the present invention is
The light source, a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, and guides light from the light source. The end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the front surface portion and the back surface portion are twisted wholly or partially with the same twist direction and twist angle. A light guide body having a concave shape, prisms, fine grooves, etc. selectively provided all over or partially, an incident surface portion for guiding the light emitted from the light guide body, and an area larger than this incident surface portion for incidence. A light guide plate including a front surface that emits light from the surface portion, a back surface opposite to the front surface, and a light guide plate and a reflector that reflects light leaked from the light guide member to the light guide plate and the light guide plate. To do.

According to a tenth aspect of the present invention, there is provided a flat illumination device in which a light source, a front surface portion for emitting light from the light source, a rear surface portion opposite to the front surface portion, and the front surface portion and the rear surface portion are sandwiched. The incident end face that guides the light from the light source has a side face smaller than the front face, the back face, and the side face, and the front face and the back face have the same twist direction and twist angle. A light guide body having fine convex or concave shapes, prisms, and fine grooves selectively provided in whole or part other than the incident end face portion and the output face portion, and an incident face portion for guiding light emitted from the light guide body. , A light guide plate having a surface having a larger area than the incident surface portion and emitting light from the incident surface portion, and a back surface opposite to the front surface, and a light guide and a leak light from the light guide body. Since it has a reflector that reflects light on the light plate, Since the light ray from is guided to the incident end surface portion of the light guide plate by changing the emission angle of the emitted light at an arbitrary position on the surface portion of the light guide body, the specified light ray can be emitted from any position of the light guide plate. . In addition, the deflection angle of light can be made larger than in the case where the twist is applied only to the front surface portion or the back surface portion.

Further, the flat illumination device according to the eleventh aspect includes a light source, an incident end face portion having a cylindrical shape for guiding light from the light source, and an emitting surface portion for emitting light from a plane twisted in the longitudinal direction of the cylindrical body. A light guide body having fine convex or concave shapes and prisms and fine grooves selectively provided in addition to the incident end face portion and the output end face portion, and guides light emitted from the light guide body. A light guide plate consisting of an incident surface portion, a surface having a larger area than the incident surface portion and emitting light from the incident surface portion, and a back surface opposite to this surface, and guiding light leaked from the light guide body. A reflector that reflects the body and the light guide plate.

A flat illumination device according to an eleventh aspect of the present invention includes a light source, an incident end surface portion having a cylindrical shape for guiding light from the light source, and an emission surface portion for emitting light from a plane twisted in the longitudinal direction of the cylindrical shape. , A light guide body in which fine convex or concave shapes and prisms and fine grooves are selectively provided in whole or part other than the incident end face portion and the output end face portion, and an incident face portion for guiding the light emitted from the light guide body And a light guide plate having a surface that has a larger area than the incident surface portion and emits light from the incident surface portion, and a back surface opposite to this surface, and a light guide plate for leaking light from the light guide body. Since the light guide plate is provided with a reflector, a light beam whose output angle from the output face of the light guide is arbitrarily changed is guided to the incident end face of the light guide plate, and the light is selectively reflected to the surface part. The light is guided in the direction and emitted from the surface.

A flat lighting device according to a twelfth aspect of the present invention is
The light source, a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, and guides light from the light source. The end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the back surface portion is composed of a large number of fine surfaces surrounded by boundaries having a large number of boundaries in the direction of both side surfaces. The light guide has an inclination and the inclination becomes smaller or larger as it gets closer to the incident end face, the incident face that guides the light emitted from the light guide, and the light from the incident face that has a larger area than this incident face. Is provided, and a light guide plate including a back surface opposite to the front surface and a reflector for reflecting light leaking from the light guide body to the light guide body and the light guide plate.

A flat illumination device according to a twelfth aspect is sandwiched between a light source, a front surface portion for emitting light from the light source, a rear surface portion opposite to the front surface portion, and the front surface portion and the rear surface portion. The incident end face portion that has a side surface and guides the light from the light source is smaller than the front surface portion, the back surface portion, and the side surface portion, and the back surface portion has a large number of boundaries in the direction of both side surfaces and is surrounded by a large number of minute boundaries. Each of the fine surfaces has an inclination with respect to the surface portion, and the inclination becomes smaller or larger as it approaches the incident end surface portion, an incident surface portion that guides the light emitted from the light guide body, and the incident surface portion. A light guide plate having a larger area and emitting light from an incident surface portion, and a back surface on the side opposite to the front surface, and reflecting light leaked from the light guide body to the light guide body and the light guide plate. Since it is equipped with a reflector, To obtain outgoing light having an arbitrary exit angle by setting the Mareta any inclination of the fine surface,
This light ray can be guided to the incident end surface portion of the light guide plate, and the specified light ray can be emitted from any position of the light guide plate.

Further, in the flat illumination device according to the thirteenth aspect, fine convex or concave shapes, prisms and fine grooves are selectively provided entirely or partially inside the reflector facing the light guide. It is characterized in that it reflects in the direction of the incident surface of the light guide and the light guide plate.

In the flat illumination device according to the thirteenth aspect, fine convex and concave shapes, prisms, and fine grooves are selectively provided entirely or partially inside the reflector facing the light guide, and the light guide is provided. Since the light is reflected in the direction of the incident surface of the body and the light guide plate, the leaked light can be returned to the light guide or a part of the leaked light can be directly projected onto the light guide plate.

Further, the flat illumination device according to claim 14 is
A fine concave-shaped portion that has a curved surface in a horizontal direction substantially perpendicular to the virtual horizontal plane and has a wedge shape with respect to the virtual horizontal plane and totally reflects in the direction of the incident surface of the light guide and the light guide plate is a light guide. Is provided inside the reflector that faces the.

According to a fourteenth aspect of the present invention, in the flat illuminating device, a surface which is substantially perpendicular to the virtual horizontal surface has a curved surface in the horizontal direction and has a wedge shape with respect to the virtual horizontal surface, and the light guide body and the light guide plate are provided in the incident surface direction. Since the minute concave shape part that totally reflects is provided inside the reflector facing the light guide plate,
It is possible to return the leaked light to the light guide body or directly project a part of the leaked light onto the light guide plate.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention does not use a direct light source for the light projected on the light guide plate, and if a general linear light source, a light beam having a high energy value coincides with a virtual horizontal line,
A light guide equipped with a point light source is provided near the light guide plate facing one end of a small rectangular or cylindrical surface, and the light guide itself serves as a substantially linear light source for the light guide plate. Two side surface parts that connect the front surface part and the back surface part to the front surface part and the back surface part that emit light from the light body are twisted, or on the back surface part opposite to the surface part that the light guide emits. By having a large number of boundaries in the direction and a large number of fine surfaces surrounded by these boundaries, and making each of these fine surfaces a surface having an inclination with respect to the surface portion, the light source entered the light guide. Refracts or totally reflects light,
A light ray with high energy emitted from the surface portion is emitted with an inclination with respect to the virtual horizontal line of the light guide body, and at the time of entering the incident end surface portion of the light guide plate, a light ray having an arbitrary inclination with respect to the incident end surface portion is generated. An object of the present invention is to provide a light guide and a flat lighting device that can project light onto an arbitrary position.

FIG. 1 is a perspective view showing a schematic structure of a flat lighting device according to the present invention, FIGS. 2 and 3 are partially enlarged views of a light guide according to the present invention, and FIG. 4 is a light guide according to the present invention. FIG. 5 is a partially enlarged side view, FIG. 5 is a ray trace diagram of light emitted from a light guide according to the present invention, FIG. 6 is a ray trace diagram in a light guide plate of a flat lighting device according to the present invention, and FIG. It is a partially expanded view of the reflector with which a plane illuminating device is equipped.

As shown in FIG. 1, the flat lighting device 1 is roughly configured to include a light guide 2, a reflector 7, a light guide plate 9, and a light source 20.

The light guide 2 is formed of a transparent acrylic resin (PMMA), polycarbonate (PC) or the like having a refractive index of about 1.4 to 1.7. The incident end face portion 5 of the light guide 2 is
The area is smaller than that of the front surface portion 3, the back surface portion 6, and the side surface portion 4, and faces the light emitting surface of the light source 20. Further, the surface portion of the incident end face portion 5 of the light guide body 2 can be made flat in addition to being formed in a concave shape toward the inside. This allows
Light emitted from the light source 20 is guided to the inside of the light guide 2 without leaking and emitted from the surface portion 3.

Further, the surface portion 3 of the light guide 2 is constructed so as to be wholly or partially twisted. In the configuration in which the surface portion 3 is twisted as a whole, the light emitted from the surface portion 3 is generally twisted and emitted from the incident end face portion 5 to the surface portion 5 ′ opposite to the incident end face portion 5 as a whole. , The emitted light is emitted downward and upward from the virtual horizontal line as it goes to the opposite surface portion 5 ′. Further, in the case where the surface portion 3 is partially twisted, the emitted light from an arbitrary portion of the surface portion 3 is emitted downward or upward with respect to the virtual horizontal line.
That is, in the case where the surface portion 3 is wholly or partially twisted, the light beam guided into the light guide 2 is continuously deflected by the twist of the surface portion 3 and is emitted from the surface portion 3.

Although not shown here, the shape of the light guide 2 may be cylindrical. When the light guide 2 has a columnar shape, since it has a columnar shape, the light of the light source 20 is guided inside from the end of the column and propagates in the column. Then, the light is repeatedly totally reflected on the surface portion of the cylinder, so that the light leaks little and the light is emitted only from the flat portion of the emitting surface portion that emits the light. Further, since the emission surface portion is twisted in the longitudinal direction of the cylinder, the emission light is emitted downward or upward relative to the virtual horizontal line, or the emission light from any portion is downward or downward relative to the virtual horizontal line. The light is emitted upward, and the same action and effect as those of the rectangular light guide 2 shown in FIG. 1 can be obtained.

Although not shown in the figure, the light guide 2 is selectively covered with fine convex or concave shapes, prisms, fine grooves, etc. on the surfaces other than the incident end face 5 and the emitting face (surface 3). Or it is partially provided. Thereby, the light ray incident from the incident end face portion 5 is reflected toward the surface portion 3 (emission surface portion) or reflected in an arbitrary direction, and the light amount and direction of the emitted light from the surface portion 3 are controlled. be able to.

Here, an example will be described in which the fine convex portion 40 is provided on the surface of the light guide 2 other than the incident end surface portion 5 and the emission surface (surface portion 3). This fine convex portion 40
As shown in FIG. 2, the surface substantially perpendicular to the imaginary horizontal plane H has a curved surface 42 in the horizontal direction and has a wedge shape with respect to the imaginary horizontal plane H. Thereby, the light beam from the light source 20 is positively controlled to emit the emitted light from the surface portion 3 and the emission surface portion.

Further details will be described with reference to FIG. As shown in FIG. 3, the fine convex portion 40 has a point a,
Surfaces b, d, f, e formed substantially perpendicular to a virtual horizontal plane H connecting the points b, e and h and the surfaces a, c connecting arbitrary positions i, j in the surfaces a, c, g, h. , I, j are tapered slopes 41, lines 46 (a, i) and lines 45 (b, f) connecting to the slopes 41, lines a, j and lines b, e and perpendiculars 44 (j, i) A large number of wedge shapes each including a triangular surface 47 surrounded by the perpendicular lines 43 (e, f) and a curved surface 42 connecting the points f and i and the points e and j are provided.

As shown in FIG. 4, a light ray Lh0 guided from a light source (not shown) (corresponding to the light source 20 in FIG. 1) to the light guide 2 is made of, for example, polycarbonate (PC) for the material of the light guide 2. When a resin is used, the refractive index n of the polycarbonate resin is n = 1.59. Therefore, the light ray Lh0 entering the light guide 2 from the air layer is expressed by the formula 0 ≦ | α | ≦ sin ⁻¹ (1 / n). (However, n is an air layer and the refractive index is n = 1).
The light present inside is in the range of approximately refraction angle α = ± 38.9713 °.

Light incident on the light guide 2 within the range of the refraction angle α = ± 38.9713 ° is sinγ at the boundary surface between the light guide 2 and the air layer (refractive index n = 1). = (1 /
The critical angle can be expressed by the equation n). For example, the refractive index of a polycarbonate resin, which is a resin material used for the light guide 2, is about n = 1.59, so the critical angle γ is about γ = 38.97 °.

When an acrylic resin (PMMA) material is used, the refractive index n of the acrylic resin is about n = 1.49, and the refraction angle α is about α = 42.38 °. The angle γ is also about γ = 42.38 °.

Therefore, as shown in FIG. 4, the light ray Lh1 that has proceeded to the side surface portion 4 and the back surface portion 6 of the light guide 2 is reflected by the curved surface 42 and emitted as the light ray Lhr as shown in FIG. Go to the face.

Similarly, the ray Lh2 shown in FIG.
The light ray Lh3 is totally reflected at 1, and the light ray Lh3 is reflected by the curved surface 42 and travels to the surface portion 3 and the emission surface portion as a light ray Lhr as shown in FIG.

In the curved surface 42, the curvature connecting the point f and the point i and the curvature connecting the point e and the point j are not necessarily equal to each other, forming a toric surface and forming the fine convex portion 40. Each curved surface 42 (42a, 42b, 42c, 42d, etc.)
Curvatures (directions toward the surface 3 and the exit surface) are not equal,
It has an arbitrary curvature and orientation so that the light rays can efficiently travel toward the surface portion 3 or the emission surface portion.

As described above, since the inclined surface 41 totally reflects in the direction of the surface portion 3 or the emission surface portion, it is possible to guide the light having directivity to the surface portion 3 or the emission surface portion, and further, the surface portion 3 or the emission surface portion or the like. By twisting, it is possible to obtain high-brightness emitted light from the surface portion 3 or the emitting surface portion and also obtain emitted light having a larger deflection amount.

Since the fine convex portion 40 has directivity, when the light source 20 is provided at both ends of the incident surface portion 5 of the light guide 2 and the opposite surface portion 5 ', each light source 20 is provided. The curved surface 42 is directed toward the light source 20 as shown in FIG.

Further, in the light guide 2, a large number of boundaries are formed on the back surface 6 between the incident end surface portion 5 and the surface portion 5'on the opposite side of the incident end surface portion 5, and are surrounded by these boundaries. It can be configured to have a large number of fine surfaces 6 '. Each of these fine surfaces 6 ′ has an inclination with respect to the surface portion 3.

Therefore, the light rays incident from the incident end surface portion 5 are reflected by the respective fine surfaces 6'of the back surface portion 6 and the emitted light corresponding to the respective fine surfaces 6'because of the inclination of the respective fine surfaces 6 '. The light is emitted from the surface portion 3. That is, the incident end face portion 5
The light rays incident from are gradually deflected by each fine surface 6 ′ and are emitted from the surface portion 3.

Further, if the inclination of the fine surface 6'is made smaller or larger as the distance from the surface portion 5'on the opposite side of the incident end surface portion 5 to the incident end surface portion 5 is decreased, the light emitted from the surface portion 3 is gradually increased. As the light emitted from the surface portion 3 is deflected and goes from the surface portion 5 ′ on the opposite side of the incident end surface portion 5 to the incident end surface portion 5, the emitted light is emitted downward or upward from the virtual horizontal line.

Here, the structure in which the light source 2 is provided only in the vicinity of one end face portion has been described as an example, but the light source 2 may be provided in the vicinity of both end face portions. In this case, the direction of the minute convex shaped portion 40 provided on the portion other than the emission surface (surface portion) 3 of the light guide 2 is also provided in the two directions of the light source 2 facing each other, and the curved surface 42 is also provided in the direction of the two light sources 2.

At the time of optical design, the angle of the curved surface 42 is also unique to each of the minute concave portions 40 so as to surely guide the light emitted from the light guide 2 to the incident surface portion 12 of the light guide plate 9. Have an angle.

The light guide plate 9 is formed of a transparent acrylic resin (PMMA) or polycarbonate resin (PC) having a refractive index of about 1.4 to 1.7. The light guide plate 9 includes an incident surface portion 12 that guides the light from the light guide 2, an anti-incident surface portion 14 located on the opposite side of the incident surface portion 12, and the incident surface portion 1.
2 includes a side surface portion 13 connected to the anti-incident surface portion 14, a front surface portion 10 that emits light, and a back surface portion 11 located on the opposite side of the front surface portion 10.

On the front surface portion 10 and the back surface portion 11 of the light guide plate 9,
An unillustrated convex or concave light control element that reflects or refracts light is provided. Thereby, the light beam emitted from the front surface portion 3 of the light guide 2 is taken into the light guide plate 9 through the incident surface portion 12, and the front surface portion 10 or the back surface portion 1 is controlled by the light control element.
Light is emitted from 1.

As shown in FIG. 5, a light beam emitted from the front surface portion 3 of the light guide 2 has a large number of fine surfaces 6'having a twisted state on the front surface portion 3 or an inclination provided on the rear surface portion 6. By providing the light beams L0 and Ld that are equal to the virtual horizontal line, the light beams Lu and Ld that are peculiar to each other are emitted, and the light beams that are deflected from the surface portion 3 of the light guide body 2 in the peculiar arbitrary direction are guided by the light guide plate 9. The light is guided from the incident surface portion 12 into the light guide plate 9 and emitted from the front surface portion 10 and the back surface portion 11 of the light guide plate 9 in an arbitrary direction and with an arbitrary brightness.

For example, as shown in FIG. 6, the surface portion 3 of the light guide 2 is twisted downward, and the central ray having the highest energy value with respect to the incident surface portion 12 of the light guide plate 9 emits the light ray L0 emitted downward. The light ray L1 that has been refracted reaches the back surface portion 11 of the light guide plate 9 toward the incident surface portion 12, and is totally reflected by the curved surface or inclined surface of the light control element 11a (convex shape here) provided on the back surface portion 11. Then, the totally reflected light ray L2 travels in the direction of the surface portion 10, is refracted at the surface portion 10 and is emitted to the outside as a light ray L3.

In the description of FIG. 6, the surface portion 3 of the light guide 2 is twisted downward with respect to the incident surface portion 12 of the light guide plate 9, but the incident surface portion 12 of the light guide plate 9 is described. On the other hand, even if the surface portion 3 of the light guide 2 is formed with a twisted surface in the upward direction, the same operation is obtained, and the same effect is obtained when the emitted light is directed downward as in a front light, for example.

Further, in FIG. 6, a twisted surface is formed on the front surface portion 3 of the light guide 2, but the inclination of the fine surface 6'provided on the back surface 6 of the light guide 2 should be downward. Thus, even if the surface portion 3 itself is provided in parallel with the light guide plate 9, the surface portion 3
The emitted light from the light is emitted downward similarly to the emitted light L0 in FIG.

As described above, since the central ray having the highest energy value is incident perpendicularly to the incident surface portion of the light guide plate from the light guide member provided in the vicinity of the conventional light guide plate, the light ray is incident on the incident surface portion of the light guide plate. However, in the light guide 2 of the present invention, an effective light beam having a high energy value is efficiently supplied to the light control element 11a provided on the light guide plate 9. I can guide you.

Further, since the conventional light rays emitted from the linear light source which are emitted in a single direction are provided only on the front surface and the back surface of the light guide plate, the light rays themselves entering the light guide plate are all in a single direction. However, there was a limit to the deflection by only the light guide plate, but since the emitted light of the linear light source itself that enters the light guide plate can be emitted in any direction, the shape of the light guide plate Greater flexibility for demand, brightness,
The viewing angle and the like can be freely selected.

The light source 20 is a semiconductor light emitting element, and is L
It is also possible to use an ED, a laser, or the like, which emits white light by performing wavelength conversion using a white light made of monochromatic light or RGB (red, green, blue) or a fluorescent material.

Although not shown here, the light source 20 may be integrated so as to be directly connected to the incident end face portion 5 of the light guide 2.

The reflector 7 is different from the incident end face portion 5 of the light guide 2 on which light is incident, the surface portion 3 of which light is emitted, and the incident surface portion 12 of light guide plate 9 on which light is incident and the surface portion 10 of which light is emitted. A portion of the light guide 20 is covered with a sheet formed by mixing a white material such as titanium oxide into a thermoplastic resin, a metal such as aluminum, or a metal foil laminated product or a sheet metal to cover the portion with light from the light source 20. The light other than the light emitted from the light guide plate 9 is reflected or irregularly reflected and is made incident on the light guide 2 or the light guide plate 9 again so that all the light from the light source 20 is emitted from the surface portion 10 of the light guide plate 9.

The reflector 7 is provided with fine convex or concave shapes (not shown), prisms, fine grooves, and the like (not shown) on the inner side facing the light guide 2 selectively on the entire surface or on a part thereof, and again on the light guide 2. Incident surface 12 of light guide plate 9
It can be configured to reflect in the direction.

Further, as shown in FIG. 7, the reflector 7 has points (k, l, m, n, inward) facing the light guide 2.
It is possible to adopt a configuration in which a large number of fine concave shaped portions 50 surrounded by o, p) are formed. The fine concave portion 50 has a curved surface 51 in the horizontal direction that is formed substantially perpendicular to the virtual horizontal plane R and has a wedge shape (k, l,
m, n, o, p).

In the case of the flat lighting device 1 provided with the reflector 7 having the fine concave portion 50 formed therein, the light reflected by the curved surface 51 of the fine concave portion 50 has a fine convex shape of the light guide 2. The position is set such that the incident angle becomes small with respect to the slope 41 of the portion 40. For example, the wedge-shaped directions of the fine convex portion 40 of the light guide 2 and the fine concave portion 50 of the reflector 7 are made opposite to each other.

Here, the concave portion 5 of the reflector 7
The action of the ray of 0 or the like is the same as that of the fine convex shaped portion 40 of the light guide 2, and the description thereof will be omitted because the contents are duplicated. A light beam that is deflected and leaks from the light guide body 2 can be returned to the light guide body 2 again, or can be totally reflected in the incident surface direction of the light guide plate 9 to directly project a part of the leaked light onto the light guide plate 9. it can.

When the light source 2 is provided in the vicinity of both end surfaces of the light guide 2, the minute concave portions 50 provided on the reflector 7 are also provided in the two directions of the light source 2 facing each other, and the curved surface 51 is provided.
Is also provided in the direction of the two light sources 2.

Further, at the time of optical design, the angles of the curved surfaces 51 are also minute concave shapes so that light rays leaking from the light guide 2 are surely reflected by the light guide 2 and the incident surface portion 12 of the light guide plate 9. The part 50 has a unique angle.

By the way, in the above-mentioned embodiment, only the surface portion 3 of the light guide 2 is wholly or partially twisted, and the inclination is changed with respect to the surface portion 3 so that the inclination changes as it approaches the incident end face portion. The example of the configuration in which the fine surface 6 ′ having the inclination angle is formed on the back surface portion 6 has been described, but the front surface portion 3 of the light guide 2 is made flat and only the back surface portion 6 is twisted wholly or partially. Also good. In this case, all the light in the light guide 2 is finally polarized when the surface part 3 is wholly or partially twisted, whereas in addition to the light totally emitted from the surface, Light can be projected onto the light guide plate 9, and an arbitrary partial luminance change can be performed on the light guide plate 9.

Further, the front surface portion 3 and the back surface portion 6 of the light guide body 2
It is also possible to have a twisted structure in whole or in part. In this case, the front surface portion 3 and the back surface portion 6 of the light guide body 2 are formed as totally or partially twisted surfaces having the same twist direction and twist angle. In this case, it is possible to obtain both the operational effect when the front surface portion 3 is twisted and the operational effect when the back surface portion 6 is twisted. That is,
In the surface portion 3, all the light in the light guide 2 can be finally polarized, and in addition to the light emitted entirely from the surface, specific light can be projected on the light guide plate. An arbitrary partial brightness change can be performed on the light plate 9. Moreover, the deflection angle of light can be made larger than that in the case where only one of the front surface portion 3 and the back surface portion 6 is twisted. In addition, a large number of fine surfaces 6'on the back surface portion 6
It is also possible to adopt a configuration in which a twist is added in the state in which is formed.

As described above, in the light guide and the flat lighting device of the present invention, the light from the light source is guided from the incident end face portion smaller than the side face portion sandwiched between the front surface portion and the back surface portion, and the light is emitted from the front surface portion. The surface portion (emission surface portion) or the back surface of the cylindrical light guide that emits light from the emission surface provided in the longitudinal direction of the rectangular light guide or the cylinder is twisted wholly or partially, Alternatively, a large number of fine surfaces are formed on the back surface, and each fine surface has an inclination with respect to the front surface, and the inclination is changed as it approaches the incident end surface portion, so that an arbitrary surface portion or emission surface portion that emits light rays can be obtained. The light exit angle can be changed vertically with respect to the virtual horizon depending on the position of the light guide plate. By installing this light guide body on the side surface of the light guide plate, the light from the light source can be maximized within the light guide plate. Incident on and exit from any position on the light guide plate By, it is possible to freely control the luminance and viewing angle, etc. at an arbitrary position of the light guide plate irrespective of the size of the light guide plate.

[0077]

As described above, in the light guide according to the first aspect, the incident end face portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the front surface portion is twisted in whole or in part, and the emitted light is emitted. Can be changed in whole or in part, so that the emission angle of the emitted light can be changed at any position on the surface, and the shape of the light guide plate to be symmetrical and a factor that causes deflection such as reflection and refraction of the light guide plate It is possible to provide appropriate incident light to the.

In the light guide according to the second aspect, the incident end face portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the back surface portion is wholly or partially twisted so that the emitted light is wholly or partially. It is possible to change the emission angle of the emitted light at an arbitrary position on the surface portion, which is suitable for the symmetrical shape of the light guide plate and the factors that cause deflection such as reflection and refraction of the light guide plate. Incident light can be provided. Moreover, when the surface is wholly or partially twisted, all the light in the light guide is finally polarized, whereas
In addition to the light emitted entirely from the surface, specific light can be projected on the light guide plate, and an arbitrary partial brightness change can be performed on the light guide plate.

Further, in the light guide according to the third aspect, the incident end face portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the front surface portion and the back surface portion have the same twisting direction and twisting angle as a whole or a part. Since the output light is twisted and the output light is changed wholly or partially, the output angle of the output light can be changed at any position on the surface, and the shape of the light guide plate and the reflection and refraction of the light guide plate are made symmetrical. Appropriate incident light can be provided for factors that cause deflection such as. And
In this case, all the light in the light guide body can be finally polarized on the surface portion, and in addition to the light emitted entirely from the surface, specific light can be projected on the light guide plate. Any partial brightness change can be made to the light plate. Moreover, the deflection angle of light can be made larger than that in the case where only one of the front surface portion and the back surface portion is twisted.

Further, since the light guide according to claim 4 has a cylindrical shape and the emission surface portion is a flat surface twisted in the longitudinal direction of the cylinder, there is little leakage light and the emission angle from the emission surface portion is arbitrarily changed. Therefore, it is possible to provide appropriate incident light with respect to a symmetrical shape of the light guide plate and a factor that causes deflection such as reflection and refraction of the light guide plate.

Further, in the light guide according to a fifth aspect, fine convex or concave shapes, prisms, fine grooves, etc. are selectively provided all or partly in addition to the incident end surface portion and the surface portion or the output surface portion. Therefore, the light rays guided from the incident end face portion are selectively reflected and guided toward the surface portion so as to be emitted from the surface portion. Furthermore, since the surface portion and the emitting surface portion are twisted wholly or partially, The deflection amount of the emitted light can be changed more.

According to the sixth aspect of the present invention, the light guide body has a surface which is substantially vertical to the virtual horizontal plane and has a curved surface in the horizontal direction, and has a wedge shape with respect to the virtual horizontal plane. Since a fine convex shape is provided on the part other than the incident end face part and the surface part or the exit face part, it is possible to guide the light having directivity to the surface part or the exit face part, and with high brightness from the surface part or the exit face part, It is possible to obtain emitted light with a large deflection amount.

Further, in the light guide according to claim 7, the incident end face portion is smaller than the front surface portion, the back surface portion and the side surface portion, and the back surface portion has a large number of boundaries in the direction of both side surface portions and is surrounded by the boundaries. It is composed of a number of fine surfaces, and each fine surface has an inclination with respect to the surface portion, and the inclination becomes smaller or larger as it approaches the incident end surface portion, so the inclination of any fine surface surrounded by individual boundaries is set. As a result, it is possible to obtain outgoing light having an arbitrary outgoing angle, and it is possible to change the outgoing angle of outgoing light at an arbitrary position on the back surface portion. Then, it is possible to provide appropriate incident light with respect to the symmetrical shape of the light guide plate and a factor that causes deflection such as reflection and refraction of the light guide plate.

In the flat illumination device according to the eighth aspect, the light source, the front surface portion for emitting light from the light source, the back surface portion opposite to the front surface portion, and the front surface portion and the back surface portion are sandwiched. The incident end face that guides the light from the light source is smaller than the front face, the back face, and the side face, and the front face is wholly or partially twisted. A light guide body in which minute convex or concave shapes, prisms, minute grooves, etc. are selectively provided on the entire surface or partially,
An incident surface portion that guides the light emitted from the light guide, a light guide plate that has a surface area that is larger than the incident surface portion and that emits light from the incident surface portion, and a light guide plate that is a back surface opposite to the front surface. Since the light guide and the reflector for reflecting the light leaked from the light body are reflected on the light guide plate, the light guide plate changes the emission angle of the light emitted from the light source at an arbitrary position on the surface of the light guide plate. Since the light is guided to the incident end face portion of, the specified light beam can be emitted from any position of the light guide plate. Therefore, it is possible to freely control the brightness and the viewing angle at any position of the light guide plate.

Further, the flat illumination device according to claim 9 is
The light source, a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, and guides light from the light source. The end face is smaller than the front face, the back face and the side face, and the back face is wholly or partially twisted, and fine convex and concave shapes other than the incident end face and the output face, prisms and fine grooves are selected. A light guide body that is entirely or partially provided, an incident surface portion that guides light emitted from the light guide body, and a surface that has a larger area than the incident surface portion and that emits light from the incident surface portion. Since a light guide plate including a front surface and a back surface on the opposite side and a reflector for reflecting light leaking from the light guide body to the light guide body and the light guide plate are provided, a light beam from the light source can be arbitrarily reflected on the front surface portion of the light guide body. The output angle of the output light is changed at the position Since leads to hurt surface can emit a light beam identified from an arbitrary position of the light guide plate. Therefore, it is possible to freely control the brightness and the viewing angle at any position of the light guide plate.

A flat lighting device according to a tenth aspect of the present invention is
The light source, a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, and guides light from the light source. The end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the front surface portion and the back surface portion are twisted wholly or partially with the same twist direction and twist angle. A light guide body having a concave shape, prisms, fine grooves, etc. selectively provided all over or partially, an incident surface portion for guiding the light emitted from the light guide body, and an area larger than this incident surface portion for incidence. Since a light guide plate including a front surface that emits light from the surface portion, a back surface opposite to the front surface, and a reflector that reflects the leaked light from the light guide member to the light guide member and the light guide plate, Light rays of any position on the surface of the light guide. The emission angle of the emitted light is changed, so leading to the entrance end face of the light guide plate can be emitted rays identified from an arbitrary position of the light guide plate in. Therefore, it is possible to freely control the brightness and the viewing angle at any position of the light guide plate. In addition, the deflection angle of light can be made larger than in the case where the twist is applied only to the front surface portion or the back surface portion.

Further, the flat illumination device according to the eleventh aspect includes a light source, an incident end face portion having a cylindrical shape for guiding light from the light source, and an emitting surface portion for emitting light from a plane twisted in the longitudinal direction of the cylindrical body. A light guide body having fine convex or concave shapes and prisms and fine grooves selectively provided in addition to the incident end face portion and the output end face portion, and guides light emitted from the light guide body. A light guide plate consisting of an incident surface portion, a surface having a larger area than the incident surface portion and emitting light from the incident surface portion, and a back surface opposite to this surface, and guiding light leaked from the light guide body. Since it has a reflector that reflects on the body and the light guide plate, it guides a light beam whose output angle from the output surface part of the light guide is arbitrarily changed to the incident end surface part of the light guide plate and selectively reflects this light beam. The light is guided to the surface and emitted from the surface, and the light guide plate It is possible to control the luminance and viewing angle at the position of the freely.

Further, the flat illumination device according to claim 12 is
The light source, a front surface portion that emits light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, and guides light from the light source. The end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the back surface portion is composed of a large number of fine surfaces surrounded by boundaries having a large number of boundaries in the direction of both side surfaces. The light guide has an inclination and the inclination becomes smaller or larger as it gets closer to the incident end face, the incident face that guides the light emitted from the light guide, and the light from the incident face that has a larger area than this incident face. Since the light guide plate is composed of a front surface that emits light, a back surface opposite to the front surface, and a reflector that reflects the light leaked from the light guide to the light guide and the light guide plate, the back surface of the light guide is provided. By setting the inclination of any fine surface surrounded by the individual boundaries of It is possible to obtain outgoing light with an arbitrary outgoing angle, guide this light ray to the incident end face of the light guide plate, and emit the specified light ray from any position of the light guide plate. The brightness and viewing angle can be freely controlled.

Further, in the flat illumination device according to the thirteenth aspect, fine convex or concave shapes, prisms, fine grooves and the like are selectively provided entirely or partially inside the reflector facing the light guide, Since the light is reflected in the direction of the incident surface of the light guide and the light guide plate, leaked light can be returned to the light guide or a part of the leaked light can be directly projected onto the light guide plate, resulting in high efficiency and high brightness without waste. It is possible to obtain a glint.

The flat lighting device according to claim 14 is:
A fine concave-shaped portion that has a curved surface in a horizontal direction substantially perpendicular to the virtual horizontal plane and has a wedge shape with respect to the virtual horizontal plane and totally reflects in the incident surface direction of the light guide and the light guide plate is Since it is provided inside the opposing reflectors, leaked light can be returned to the light guide or part of the leaked light can be directly projected onto the light guide plate, and high efficiency and high brightness emission light can be obtained without waste. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a flat lighting device according to the present invention.

FIG. 2 is a partially enlarged view of a light guide according to the present invention.

FIG. 3 is a partially enlarged view of a light guide according to the present invention.

FIG. 4 is a partially enlarged side view of a light guide body according to the present invention.

FIG. 5 is a ray trace diagram of light emitted from a light guide according to the present invention.

FIG. 6 is a ray trace diagram in the light guide plate of the flat lighting device according to the present invention.

FIG. 7 is a partially enlarged view of a reflector provided in the flat illumination device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Planar illuminating device, 2 ... Light guide, 3 ... Front surface part, 4 ... Side surface part, 5 ... Incident end surface part, 5 '... Surface part opposite to an incident end surface part, 6 ... Back surface part, 6' ... Fine surface , 7 ... Reflector, 9 ...
Light guide plate, 10 ... Front surface portion, 11 ... Back surface portion, 12 ... Incident surface portion, 13 ... Side surface portion, 14 ... Anti-incident surface portion, 20 ... Light source, 4
0 ... Fine convex portion, 42 ... Curved surface, 41 ... Slope, 47 ... Side surface, 50 ... Fine convex portion, L0, Lh0, Lhr, Lh
1, Lh2, Lh3, L1, L2, L3, Ld, Lu ...
Bright lines, H, R ... Virtual horizontal plane.

Claims (14)

[Claims] 1. An incident end face portion for guiding light from a light source, a front surface portion for emitting the light, a rear surface portion opposite to the front surface portion, and a side surface sandwiched between the front surface portion and the rear surface portion. In the light guide having a portion, the incident end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the front surface portion is wholly or partially twisted, and the emitted light is wholly or partially A light guide characterized by being changed. 2. An incident end face portion for guiding light from a light source, a front surface portion for emitting the light, a rear surface portion opposite to the front surface portion, and a side surface sandwiched between the front surface portion and the rear surface portion. In the light guide having a portion, the incident end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the back surface portion is twisted wholly or partially, and the outgoing light is wholly or partially twisted. A light guide characterized by being changed. 3. An incident end face portion for guiding light from a light source, a front surface portion for emitting the light, a rear surface portion opposite to the front surface portion, and a side surface sandwiched between the front surface portion and the rear surface portion. In the light guide having a portion, the incident end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the front surface portion and the back surface portion have the same twisting direction and twisting angle in whole or in part. A light guide body which is twisted to change the emitted light in whole or in part. 4. A light guide body having an incident end surface portion for guiding light from a light source and an emission surface portion for emitting the light, wherein the light guide body has a cylindrical shape, and the emission surface portion has a longitudinal direction of the cylinder. A light guide characterized by being a plane twisted in a direction. 5. A fine convex or concave shape, a prism, a fine groove and the like are selectively provided on the entire surface or a part other than the incident end surface portion and the surface portion or the output surface portion. The light guide according to any one of 1 to 4. 6. A fine convex portion that has a curved surface in a horizontal direction substantially perpendicular to the virtual horizontal plane and has a wedge shape with respect to the virtual horizontal plane and totally reflects in the direction of the surface portion or the emission surface portion. The light guide according to any one of claims 1 to 4, wherein the light guide is provided at a position other than the entrance end face and the surface or the exit face. 7. An incident end face portion that guides light from a light source, a front surface portion that emits the light, a back surface portion opposite to the front surface portion, and a side surface sandwiched between the front surface portion and the back surface portion. In the light guide having a portion, the incident end surface portion is smaller than the front surface portion, the back surface portion, and the side surface portion, and the back surface portion has a large number of boundaries in the direction of both side surfaces and is surrounded by the boundaries. 2. The light guide body according to claim 1, wherein each of the fine surfaces has an inclination with respect to the surface portion, and the inclination becomes smaller or larger toward an entrance end surface portion. 8. A light source, a front surface portion for emitting light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, An incident end surface portion that guides light from the light source is smaller than the front surface portion, the back surface portion, and the side surface portion, and the front surface portion is wholly or partially twisted,
A light guide body in which fine convex or concave shapes, prisms, fine grooves, etc. are selectively provided all or partly in addition to the incident end surface portion and the output surface portion, and an incident light for guiding light emitted from the light guide body. A light guide plate consisting of a surface portion, a surface having a larger area than the incident surface portion, which emits light from the incident surface portion, and a back surface opposite to the surface, and leakage light from the light guide member. A flat lighting device comprising: a light guide and a reflector that reflects the light guide plate. 9. A light source, a front surface portion for emitting light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, An incident end surface portion that guides light from the light source is smaller than the front surface portion, the back surface portion, and the side surface portion, and the back surface portion is twisted wholly or partially,
A light guide body in which fine convex or concave shapes, prisms, fine grooves, etc. are selectively provided all or partly in addition to the incident end surface portion and the output surface portion, and an incident light for guiding light emitted from the light guide body. A light guide plate consisting of a surface portion, a surface having a larger area than the incident surface portion, which emits light from the incident surface portion, and a back surface opposite to the surface, and leakage light from the light guide member. A flat lighting device comprising: a light guide and a reflector that reflects the light guide plate. 10. A light source, a front surface portion for emitting light from the light source, a rear surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the rear surface portion, The incident end face portion that guides the light from the light source is smaller than the front surface portion, the back surface portion, and the side surface portion, and the front surface portion and the back surface portion are twisted in the same twist direction and twist angle, wholly or partially. , A light guide body in which fine convex or concave shapes and prisms and fine grooves are selectively provided on the entire surface or a part other than the incident end surface portion and the output surface portion, and light emitted from the light guide body is guided. An incident surface portion, a surface having a larger area than the incident surface portion, which emits light from the incident surface portion, a light guide plate including a back surface opposite to the surface, and leakage light from the light guide body. It reflects on the light guide and the light guide plate. A flat lighting device, comprising: 11. A light source, an incident end face portion having a cylindrical shape for guiding light from the light source, and an emitting face portion for emitting light from a plane twisted in the longitudinal direction of the cylindrical body, the incident end face portion, and In addition to the exit end face portion, a light guide body provided with fine convex or concave shapes and prisms and fine grooves selectively or entirely, and an incident surface portion that guides the light emitted from the light guide body, A light guide plate that has a surface area that is larger than the incident surface portion and that emits light from the incident surface portion, and a light guide plate that is composed of a back surface opposite to this surface, and leaks light from the light guide body to the light guide body and A flat lighting device comprising: a reflector that reflects the light guide plate. 12. A light source, a front surface portion for emitting light from the light source, a back surface portion opposite to the front surface portion, and a side surface portion sandwiched between the front surface portion and the back surface portion, The incident end face portion that guides the light from the light source is smaller than the front surface portion, the back surface portion, and the side surface portion, and the back surface portion has a large number of boundaries in the direction of both side surface parts and is surrounded by a large number of fine particles. A light guide body that is formed of a surface, each fine surface having an inclination with respect to the surface portion, and the inclination becomes smaller or larger toward the incident end surface portion; and an incident surface portion that guides light emitted from the light guide body. And a light guide plate having a surface that has a larger area than the incident surface portion and emits light from the incident surface portion, and a back surface opposite to this surface, and the light leaked from the light guide body is guided by the light guide plate. An optical body and a reflector that reflects the light guide plate A flat lighting device characterized by being provided. 13. The light reflector and the light guide plate, wherein the reflector is provided with fine convex or concave shapes, prisms, fine grooves, or the like selectively on the entire surface or a part thereof on the inner side facing the light guide. The flat illumination device according to any one of claims 8 to 12, wherein the flat illumination device reflects the light in the direction of the incident surface. 14. The reflector has a surface which is substantially vertical to a virtual horizontal plane and has a curved surface in the horizontal direction, and has a wedge shape with respect to the virtual horizontal plane, and is directed toward the incident surface portion of the light guide and the light guide plate. The flat illumination device according to any one of claims 8 to 12, wherein a fine concave portion that totally reflects the light is provided inside the light guide body.