JP2003281911A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device of constant-brightness illumination, high directivity in light beam, and high utilization of the light beam. <P>SOLUTION: The lighting device comprises a light source 201, a lightguide plate 202, and a reflecting plate 203. The lightguide plate 202 is provided with multiple grooves 207 on its rear surface 202a which directs the light from an incident surface toward an exit surface. The multiple grooves 207 at the part closer to the incident surface and the part closer to the end on the side opposite to the incident surface have a narrow pitch P2 compared to a central part. The light quantity advancing toward the exit surface becomes larger at the lightguide plate at the part closer to the incident surface and the part closer to the tip end, thus brightness distribution is constant over the entire light emission surface. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device,
In particular, the present invention relates to a lighting device applied to a backlight of a transmissive liquid crystal display device or the like.

In recent years, display units have been used in large numbers in word processors, personal computers, etc. due to the expansion of display capacity or improvement of characteristics. Further, a display unit having a large screen size for a workstation is required from a notebook, which is thin and lightweight, and a lighting device with high brightness and high efficiency is desired for colorization.

[0003]

2. Description of the Related Art Conventionally, an edge-light type backlight used in a liquid crystal display device is such that a light is incident from a side surface of a light guide plate, and internally propagated light due to total reflection is inclined in a central part thereof and a white ink. As a result, the total reflection condition was broken and the light was emitted to the light emitting surface side.

FIG. 40 is an explanatory view of a conventional edge light type illumination device.

In the figure, 81 is a fluorescent tube as a light source,
Reference numeral 82 is a light guide plate made of transparent resin, 82a is an incident surface of the light guide plate 82, 82b is a back surface of the light guide plate 82 on which a diffuse reflection pattern is printed, 82c is an exit surface of the light guide plate 82, 83 is a reflection sheet, and 84 is light emission. Surface, 85 is a reflecting mirror provided so as to surround the fluorescent tube 81, 86 is a linear prism, 87 is a diffusion sheet, 88 is internally propagating light, and 89 is outgoing light, and 90 is
Is a lighting device composed of them.

As shown in the figure, in the conventional edge light type backlight, the fluorescent tube 81 surrounded by the reflecting mirror 85 is
The emitted light is arranged so as to enter from the incident surface 82a of the light guide plate 82. The light guide plate 82 is inclined from both ends toward the center so that the thickness of the light guide plate 82 becomes thinner toward the center. There is. Then, the back surface 82b of the light guide plate 82
The diffused reflection pattern of white ink, etc.
The print sheet is weighted so that the print area becomes larger as it goes away from 1, and a reflection sheet 83 for effectively emitting the light rays scattered by the diffuse reflection pattern is arranged on the back surface of the back surface 82b. Further, a linear prism 86 for collecting outgoing light 89 in the normal direction is provided on the light emitting surface 84 above the light guide plate 82, and the linear prism 86 is further provided.
An edge light type illumination device 90 is configured by disposing a diffusion sheet 87 on the emission direction side of so that the diffuse reflection pattern of the back surface 82b is not visually recognized.

In the conventional edge light type illumination device 90, the diffused light emitted from the fluorescent tube 81 enters from the incident surface 82a of the light guide plate 82 and propagates inside the light guide plate 82 while satisfying the total reflection condition. To go. Internal propagation light 88
Since the emission surface 82c of the light guide plate 82 is inclined toward the central portion, the angle becomes steep by the inclination angle θ of the emission surface 82c every time it is totally reflected by the emission surface 82c, and when the angle becomes equal to or greater than the critical angle. The emitted light 89 is emitted from the emission surface 82c, and on the other hand, the propagation light 88 that is totally reflected by the emission surface 82c and reaches the back surface 82b is emitted from the light emitting surface 84 because the total reflection condition is broken by the diffuse reflection pattern. There is.

[0008]

In the conventional edge light type illuminating device, not all the light rays emitted from the fluorescent tube and diffused and reflected by the diffuse reflection pattern are emitted to the light emitting surface side, but a part is internally propagated. It is the current situation that light rays are lost by repeatedly colliding with the fluorescent tube on the opposite surface. In order to reduce this phenomenon, an attempt has been made to improve the thickness of the light guide plate by making the exit surface of the light guide plate slanted toward the center, but it is still insufficient and the light utilization rate is low. There was a problem.

Further, a linear prism plate is arranged between the light guide plate and the diffusion plate for the purpose of effectively improving the luminance in the normal direction. The prism pitch and matrix of the linear prism plate are arranged. Since interference occurs if the inter-electrode pitch of the flat display panel is not optimum, the occurrence of interference has been reduced by using a diffuser plate having a high degree of diffusion or setting an optimum pitch for each model. However, there are problems that the brightness in the normal direction decreases if the degree of diffusion is increased, and that the cost increases if a die for a linear prism suitable for each model is manufactured.

Therefore, an object of the present invention is to realize a highly efficient lighting device having high brightness and uniform brightness distribution, which is thin and lightweight.

[0011]

According to a first aspect of the present invention, a light source (201), an incident surface (202c) on which a light ray from the light source (201) is incident, and an emission surface (202b) on which the incident light ray is emitted. A light guide plate (202) having a light guide plate (202) and a reflection plate (203) arranged on the back surface (202a) side of the light guide plate and reflecting light rays toward the light guide plate. , On its back surface (202a), a plurality of grooves (207) for directing the light incident from the incident surface toward the exit surface are provided on the back surface (202a) and on the opposite side of the part near the entrance surface and the entrance surface. The parts near the edges are arranged with a narrower pitch (P2) than the center part.

According to a second aspect of the present invention, a light source (201), an incident surface (202Ac) on which a light ray from the light source is incident, an emission surface (202Ab) on which the incident light ray is emitted, and the emission surface (202Ab). A light guide plate (202A) having a back surface (202Aa) facing the light guide plate (202Aa), and a reflection plate (203) arranged to face the back surface (202Aa) of the light guide plate (202A).
In the illuminating device provided with, the light guide plate is provided on the back surface thereof with a large number of grooves (207-) for directing light toward the emission surface.
1 to 207-n) and covers a portion of the emission surface corresponding to at least one groove of the grooves (207-1 to 207-n) near the incident surface.
Aa) is provided.

According to a third aspect of the present invention, a light source (201) and an incident surface (202) on which a light ray from the light source (201) is incident.
c) and a light guide plate (202) having an exit surface (202b) through which an incident light beam exits, and a back surface (202) of the light guide plate.
In a lighting device provided with a reflection plate (203) which is arranged on the a) side and reflects a light beam toward the light guide plate, the light guide plate is provided on the back surface thereof with the light propagating in the light guide plate. A large number of grooves (207-1 to 207-
n) has a configuration in which a portion of the back surface near the incident surface and a portion near the end opposite to the incident surface are arranged with a narrower pitch (P2) than the central portion, and A reflecting mirror (205Aa) is provided to cover a portion of the emitting surface corresponding to the groove near the incident surface.

According to a fourth aspect of the invention, a light guide plate having a light source (201), an incident surface on which a light ray from the light source is incident, an emission surface from which the incident light ray is emitted, and a back surface facing the emission surface. And a reflection plate (2
03) and a light guide plate (24)
A large number of grooves (207) for directing 1) on the back surface (241a) thereof in the direction of the emission surface propagating in the light guide plate.
In the rear surface, the portion near the incident surface and the portion near the end opposite to the incident surface are arranged with a narrower pitch (P2) than the central portion, and are inclined. It is configured to have a flat emission surface (241b) and a curved tip surface (241c).

According to a fifth aspect of the invention, a light guide plate having a light source (201), an incident surface on which a light ray from the light source is incident, an emission surface from which the incident light ray is emitted, and a back surface facing the emission surface. And a reflection plate (2
03), the light guide plate has a pit group on the back surface thereof, the pit group having a number of pits each having a substantially triangular cross section and directed toward the emission surface propagating in the light guide plate. However, the pit group is configured such that a large number of pit rows (254) in which the pits are arranged are aligned and the pits are arranged in a staggered manner between adjacent pit rows.

According to a sixth aspect of the present invention, there is provided a light guide plate having a light source (201), an incident surface on which a light ray from the light source is incident, an emission surface on which the incident light ray is emitted, and a back surface facing the emission surface. And a reflection plate (2
03) and a light guide plate (26
1) has a configuration in which a large number of grooves (262) directed to the emission surface propagating in the light guide plate are arranged on the back surface in a crossed arrangement.

According to a seventh aspect of the invention, a light guide plate having a light source (201), an incident surface on which a light ray from the light source is incident, an emission surface from which the incident light ray is emitted, and a back surface facing the emission surface. And a reflection plate (2
03) and a light guide plate (27).
1) is provided on its back surface with a large number of substantially triangular grooves (272-2) which are directed toward the emission surface propagating in the light guide plate.
77), the size is increased toward the incident surface, and the pitches are arranged at equal pitches.

According to an eighth aspect of the present invention, there is provided a light guide plate having a light source (201), an incident surface on which a light ray from the light source is incident, an emission surface from which the incident light ray is emitted, and a back surface facing the emission surface. And a reflection plate (2
03) and a light guide plate (28)
1) has a pit group (282) on its back surface, which is made up of a large number of pits each having a substantially triangular cross section and which faces the direction of the emission surface propagating in the light guide plate. Is arranged so that the pit rows (284, 285) arranged side by side intersect.

According to a ninth aspect of the present invention, the light source (201), the incident surface on which the light rays from the light source are incident, the emission surface on which the incident light rays are emitted, and the emission surface are opposed to each other, and a uniform pitch is provided. In a lighting device including a light guide plate having a back surface having a groove (318) and a reflection plate (203) arranged so as to face the back surface of the light guide plate, the reflection plate (312) is provided at an upper surface thereof. Has a plurality of ridges (313) for reflecting the light leaked from the back surface of the light guide plate and directing the light toward the light guide plate, and the plurality of ridges are close to the incident surface of the light guide plate. The portion and the portion closer to the end on the side opposite to the incident surface are arranged with a narrower pitch (P11) than the central portion.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of the principle relating to the present invention.

In the figure, 1 is a light source, 2 is a light guide plate, and 2 is a light guide plate.
a is an incident surface of the light guide plate 2, 2b is a rear surface of the light guide plate 2, 2c is an exit surface of the light guide plate 3, 3 is a reflection surface, 3a is a side wall surface of the reflection surface 3 facing the light source 1, 4 is a light emission surface, Reference numeral 5 is a space portion.

As shown in the figure, the illumination device according to the present invention includes a light source 1 and an incident surface 2a on which light rays from the light source 1 are incident.
A light guide plate 2 having an emission surface 2c through which the incident light beam exits, and a reflection surface 3 that is arranged on the back surface 2b side of the light guide plate 2 and reflects the light beam toward a light emitting surface 4 provided above the light guide plate 2. In the illuminating device including the light guide plate 2, the emission surface 2c is formed such that the thickness of the light guide plate 2 becomes thinner as the light guide plate 2 moves away from the light source 1 arranged on the side of the light guide plate 2.
A space 5 sandwiched between the reflective surface 3 and the light emitting surface 4 is formed between the tip of the reflective surface 3 and the reflective side surface 3a facing the light source 1 with the light guide plate 2 of the reflective surface 3 interposed therebetween. It is characterized by

Further, the exit surface 2c of the light guide plate 2 is a rear surface 2b.
And a plurality of continuous planes having different inclination angles with each other, and the inclination angle of the plane on the tip side of the light guide plate 2 is larger than the inclination angle of the plane on the incident surface 2a side.

Further, it is characterized in that the incident surface 2a of the light guide plate 2 is a diffusion surface provided with irregularities.

Further, the back surface 2b of the light guide plate 2 is a diffusion surface.

Further, the light emitting surface 2c of the light guide plate 2 is a diffusion surface.

Further, a transparent diffusion sheet is arranged between the back surface 2b of the light guide plate 2 and the reflection surface 3.

Further, it is characterized in that the reflecting surface 3 is an uneven surface.

Further, at least one linear prism plate for converging the outgoing light in the normal direction is provided on the light emitting side of the light emitting surface 4, and at least one of them is in the axial direction of the linear prism plate. And the relative position with respect to the direction of the matrix electrode pattern of the display device arranged on the light emitting surface 4 is arranged so as not to be parallel or orthogonal.

As another aspect of the lighting device according to the present invention, the lighting device according to the present invention is used as a unit unit and is composed of a plurality of unit units, and the light emitting surfaces 4 of the respective unit units are on the same plane. Is characterized in that a plurality of unit units are arranged in a plane.

As yet another aspect of the illuminating device according to the present invention, the illuminating device according to the present invention is used as a unit unit and includes a plurality of unit units, and the reflecting surface 3 and the light emitting surface 4 of the unit unit are adjacent to each other. Thus, a plurality of unit units are laminated, and the side wall surface 3a side of the unit unit is used as a light emitting surface.

FIG. 2 is a diagram for explaining the operation of the lighting device related to the present invention.

In the figure, 1 is a light source, 2 is a light guide plate for propagating light from the light source, 2a is an incident surface of the light guide plate 2 on which light from the light source is incident, 2b is a back surface of the light guide plate 2, and 2c is a light guide plate. The thickness of the light plate 2 becomes thinner as the distance from the light source 1 increases,
An emission surface 3 formed with the angle formed with the back surface b is θ, through which the light propagating inside the light guide plate 2 is emitted, and the light emission surface 3 faces the back surface 2b of the light guide plate 2 and emits the light emitted from the back surface 2b in the emission surface 2c direction. A light-reflecting surface 3a reflects light from the light source 1 and a light-reflecting surface 3a sandwiches the light guide plate 2 and faces the light source 1.
The light emitting surface 5 that emits light via the light emitting surface 2c, the reflecting surface 3,
A space where the side wall surface 3a and the light emitting surface 4 are sandwiched, 6 is a reflecting mirror that surrounds the light source 1 and reflects the light from the light source 1 in the direction of the incident surface 2a of the light guide plate 2, and 7 is incident from the incident surface 2a. Internally propagating light propagating in the interior, 8 is outgoing light propagating in the light guide plate and then exiting from the exit surface 2c, and 10 is an illuminating device composed of these.

Illumination device 1 according to the present invention as shown in FIG.
In 0, the light emitted from the light source 1 is reflected by the reflecting mirror 6, and the light repeatedly repeated multiple reflections with the light source 1 and the direct light are combined and made incident from the input surface 2a of the light guide plate 2.

Here, the light incident on the light guide plate 2 is incident at about ± 42 ° with respect to the normal line of the incident surface according to Snell's law, and when the surface of the light guide plate is a surface perpendicular to the incident surface, The angle of the light ray reaching the surface of the light guide plate is about ± 48 ° or more with respect to the normal line of the surface of the light guide plate, and is totally reflected and propagates inside the light guide plate. Therefore, when the surface of the light guide plate is a surface perpendicular to the incident surface, all the propagating light is emitted from the end surface of the light guide plate facing the light source.

However, in the light guide plate 2 of the illuminating device 10 according to the present invention, the emitting surface 2c is inclined such that the angle formed with the back surface 2b is θ so that the thickness of the light guide plate 2 becomes thinner as the distance from the light source 1 increases. Since the propagating light 7 incident from the entrance surface 2a is totally reflected by the exit surface 2c, the angle with respect to the exit surface 2c becomes steep by an inclination angle θ. Then, while repeating the reflection, a part of the propagating light 7 is emitted from the emitting surface 2c as the outgoing light 8 toward the light emitting surface 4, and a part of the propagating light 7 is repeatedly propagated as the propagating light 7. Further, although the propagating light 7 is also partially emitted from the back surface 2b, it is reflected toward the light emitting surface 4 by the reflecting surface 3 facing the back surface 2b.

The emitted light 8 emitted from the tip end side of the light guide plate 2 directly reaches the light emitting surface 4, and the light emitted from the light emitting surface 4 after being reflected by the side wall surface 3a of the reflecting surface 3 without directly reaching the light emitting surface 4. Some are emitted.

Here, when the reflection side surface is provided adjacent to the end of the light guide plate which is remote from the light source, the number of light rays reflected by the reflection side surface increases and the light loss rate increases. Alternatively, the light ray that directly exits the light guide plate and then reaches the light emitting surface and the light ray that reaches the light emitting surface after being reflected by the reflecting side surface overlap each other slightly inside the end of the light emitting surface. Will occur.

However, in the illuminating device 10 according to the present invention, a space is provided between the tip of the light guide plate 2 and the side wall surface 3a, and the reflecting surface 3 and the light emitting surface 4 are provided between the light guide plate 2 and the side wall surface 3a.
By arranging the space portion 5 sandwiched by the
Almost all of the emitted light 8 emitted from the light source can be directly emitted to the direction of the light emitting surface 4, the luminance distribution is made uniform, the light loss is reduced, and the efficiency is high.

FIGS. 3A and 3B are views showing a first embodiment of the illuminating device according to the present invention. FIG. 3A is a sectional view and FIG. 3B is a diagram showing the luminance distribution of the illuminating device of this embodiment. Is.

In FIG. 1A, 11 is a fluorescent tube and 12 is a fluorescent tube.
Is a light guide plate, 12a is an incident surface of the light guide plate 12, 12b is a back surface of the light guide plate 12, 12c 'is a first exit surface of the light guide plate 12,
Reference numeral 12c ″ is a second emission surface, 13 is a reflecting surface, 14 is a light emitting surface, 15 is a space portion, 16 is a reflecting mirror, and 20 is an illuminating device composed of them.

As shown in FIG. 4A, the illumination device of this embodiment has a light emitting side of a fluorescent tube 11 which is surrounded by a reflecting mirror 16 in a semicircular shape in order to collect emitted light in one direction. Incident surface 12
The light guide plate 12 is arranged so that a faces the light source 11. The light guide plate 12 has an emission surface inclined such that the thickness thereof becomes thinner as the distance from the light source 11 increases, and the emission surface is a first emission surface 12c 'which forms an angle θ1 with the rear surface 12b on the light source 11 side. , Angle θ with respect to the rear surface 12b on the tip side
The second output surface 12c ″ is formed of 2 and the angle θ2 is larger than the angle θ1, and the boundary between the first output surface 12c ′ and the second output surface 12c ″ is chamfered to be a curved surface. In addition, a reflecting surface 13 is provided so as to face the back surface 12b of the light guide plate 12,
The side wall surface 13 a of the reflecting surface 13 is arranged on the side facing the light source 11, and the light emitting surface 14 is provided on the side facing the reflecting surface 13. A space is provided between the tip of the light guide plate 12 and the side wall surface 13 a, and the light exit surface 12 of the light guide plate 12 is provided.
A space portion 15 surrounded by c ′ and 12c ″, the reflecting surface 13, the side wall surface 13a and the light emitting surface 14 is provided.

As in the present embodiment, the shape of the light guide plate 12 has an inclination angle θ1 with respect to the back surface 12b of the first light emitting surface 12c 'on the light source 11 side and the back surface 1 of the second light emitting surface 12c "on the tip side.
By making the inclination angle θ2 with respect to 2b different and forming the angle of θ2 larger than θ1,
Since the emitted light can be appropriately dispersed and emitted without being concentrated on the tip portion, the light ray utilization rate is improved and the luminance distribution at the end portion of the light emitting surface 14 can be made uniform, and further, the processing at the time of molding the light guide plate 12 can be performed. Yields can be improved because the tip is easier than that with an acute angle, damage to the tip is reduced, and handling is easy.

Further, FIG. 6B shows that in the lighting device of this embodiment, the angle θ1 is changed and the angle θ1 is changed (θ2>
FIG. 4 is a diagram showing the luminance distribution in the case of (.theta.1), and a solid line 401 shows a case where the angle .theta.1 is small, and a broken line 402 shows a case where the angle .theta.1 is large.

As shown in the figure, when the angle .theta.1 is small, the number of light rays emitted from the first emission surface 12c 'is small and propagates to the tip side of the light guide plate 12, so that the amount of light emitted on the tip side is large. Although the brightness is high, when the angle θ1 is large, the amount of light emitted from the first emission surface 12c ′ increases,
On the other hand, since the amount of light emitted from the second emission surface 12c ″ decreases, the brightness distribution becomes uniform. However, the brightness distribution on the tip end side similarly increases / decreases in proportion to the angle θ1.

Although a diffusing surface or a mirror surface can be used as the reflecting surface 13, if the reflecting surface 13 is a diffusing surface, the light rays emitted from the rear surface 12b of the light guide plate 12 are diffused, so that the light source 11 is near the light source 11. The amount of emitted light is increased, and the brightness distribution can be made uniform.

FIG. 4 is a diagram showing a second embodiment of the illuminating device according to the present invention, FIG. 4 (a) is a sectional view, and FIG. 4 (b) is a diagram showing the luminance distribution of the illuminating device of this embodiment. Is.

In the figure (a), 21 is a fluorescent tube, 22
Is a light guide plate, 22a is an incident surface of the light guide plate 22, 22b is a back surface of the light guide plate 22 on which a diffuse reflection pattern is printed, and 22c '.
Is the first exit surface of the light guide plate 22 provided with the shape diffusion portion,
22 c ″ is a second emitting surface, 23 is a reflecting surface, 24 is a light emitting surface, 25 is a space portion, 26 is a reflecting mirror, and 30 is an illuminating device composed of them.

As shown in FIG. 9A, the lighting device of this embodiment is different from that of the first embodiment in the shape of the light guide plate 22, and the first exit surface 22c 'is a flat surface provided with a shape diffusion portion. The diffuse reflection pattern is also printed on the back surface 22b.

As in this embodiment, the back surface 22b and the first emission surface 22c 'are provided with a shape diffusing portion composed of an uneven surface or a diffuse reflection pattern printed with a white paint or the like to make the luminance distribution uniform. Can be achieved.

The positions where the shape diffusion portion and the diffuse reflection pattern are provided are not limited to the back surface 22b and the first emission surface 22c ', but the shape diffusion portion is provided on the back surface 22b and the diffusion reflection pattern is provided. Can be provided on the first exit surface 22c '. Furthermore, the diffusion printing pattern can improve the luminance distribution by weighting it so that the printing area is changed according to the distance from the light source.
If the illuminating device is relatively small and the inclination angle of the exit surface of the light guide plate is large, weighting may not be performed.

Further, FIG. 6B is a diagram showing the luminance distribution when the weighted diffuse reflection pattern is printed only on the back surface 22b of the light guide plate 22 in the lighting apparatus of this embodiment, and the broken line 403 is shown. The luminance distribution due to the light rays emitted from the first emission surface 22c ', the one-dot chain line 404 is the second emission surface 22
It is the luminance distribution due to the light rays emitted from c ", and the solid line 40
5 is the overall luminance distribution synthesized by them.

As shown in the figure, it can be seen that the weighted diffuse reflection pattern is provided on the back surface 22b to make the luminance distribution uniform, and by adopting the configuration shown in this embodiment, the light ray utilization rate is high, The lighting device can have a uniform luminance distribution.

FIG. 5 is a diagram showing a third embodiment of the lighting device according to the present invention.

In the figure, 31 is a fluorescent tube, 32 is a light guide plate, 32a is an incident surface of the light guide plate 32 having an uneven surface whose axis is parallel to the fluorescent tube 31, 32b is a back surface of the light guide plate 32, and 3b.
2c 'is the first emission surface of the light guide plate 32, 32c "is the second emission surface of the light guide plate 32, 33 is a reflection surface, 34 is a light emission surface, 3
Reference numeral 5 is a space portion, 36 is a reflecting mirror, 37 is a transparent diffuse reflection sheet on which a diffuse reflection pattern is printed, and 40 is an illuminating device constituted by them.

As shown in the figure, in the illumination device of this embodiment, the shape of the light guide plate 32 is different from that of the first and second embodiments, and the axis is parallel to the fluorescent tube 31 on the incident surface 32a of the light guide plate 32. The corrugated uneven surface is provided. Further, the light guide plate 32
On the back surface 32b side of the, between the back surface 32b and the reflecting surface 33,
A transparent diffuse reflection sheet having a diffuse reflection pattern printed thereon is provided.

This embodiment is suitable for a relatively small backlight, and since the incident surface 32a is provided with a corrugated corrugated surface whose axis is parallel to the fluorescent tube 31, the propagation of the light beam incident from the incident surface 32a. The direction can be about ± 42 ° or more with respect to the normal when the incident surface 32a is perpendicular to the back surface 32b. Therefore, it is possible to increase the amount of emitted light in the vicinity of the fluorescent tube 31. Furthermore, the back surface 32b
The brightness distribution can be made uniform by the diffuse reflection sheet 37 provided between the reflection surface 33 and the reflection surface 33.

6A and 6B are views showing a fourth embodiment of the illuminating device according to the present invention, wherein FIG. 6A is a sectional view and FIG. 6B is a plan view for explaining a method of disposing a linear prism plate. Is.

In the figure, 41 is a fluorescent tube, 42 is a light guide plate, 42a is an incident surface of the light guide plate 42, 42b is a back surface of the light guide plate 42 on which a diffuse reflection pattern is printed, and 42c 'is the first of the light guide plate 42. Of the light guide plate 42, 43c is a reflection surface, 43a is a side wall surface of the reflection surface 43,
44 is a light emitting surface, 45 is a space, 46 is a reflecting mirror, 47 is a linear prism plate, 48 is a diffusion sheet, and 50 is an illuminating device composed of them.

As shown in the figure, in the lighting device of this embodiment, the reflecting surface 43 and the side wall surface 43a of the reflecting surface 43 are different from those in the first to third embodiments, and the reflecting surface 43 and the side wall surface 43 are different.
a is not orthogonal, but the reflecting surface 43 and the side wall surface 43a
And are continuously formed as curved surfaces. Furthermore, the light guide plate 3
A weighted diffuse reflection pattern is printed on the back surface 32b of No. 2, and a linear prism plate 47 for giving directivity in the normal direction to the emitted light is arranged on the light emitting surface 44 at the axis and the upper part thereof. The display device (not shown) is arranged so as not to be orthogonal or parallel to the axial direction of the matrix electrodes. A diffusion sheet 48 is arranged above the linear prism plate 47 so that the diffusion print pattern printed on the back surface 42b of the light guide plate 42 is not visible.

As in this embodiment, the reflecting surface 43 and the side wall surface 4
When 3a is formed by a continuous curved surface, the loss of the light emitted from the light guide plate 42 is reduced, the light utilization factor is improved, and the luminance distribution can be made uniform.

Further, FIG. 9B shows the linear prism plate 47.
Is a plan view for explaining the arrangement method of the linear prism plate 47. The prism axis 47a of the linear prism plate 47 has an inclination angle φ (0 ° <0 ° <0 ° <0 ° <0 ° <0 < φ <90 °). By arranging the linear prism plate 47 in this way, it is possible to prevent deterioration of display image quality due to interference.

FIG. 7 is a diagram (No. 1) showing the directional characteristics of the light guide plate. FIG. 7A is a perspective view, and FIG. 7B is a diagram showing the relationship between the emission angle of the light beam and the relative luminance. .

In FIG. 10A, 51 is a fluorescent tube which serves as a light source, 52 is a light guide plate which is arranged on the side of the fluorescent tube 51,
2a is an incident surface of the light guide plate 52 facing the fluorescent tube 51,
b is the back surface of the light guide plate 52, 52c is the exit surface of the light guide plate 52 that forms an angle θ with the back surface 52b, 54 is a reflecting mirror that surrounds the fluorescent tube 51, and 58 is the propagation light inside the light guide plate 51.
Reference numeral 59 denotes the emitted light emitted from the emitting surface 59c, which has an angle θ.
Is set to 10 °. Hereinafter, components having the same function are designated by the same reference numeral, and description thereof will be omitted.

In the figure, a fluorescent tube 51 serving as a light source.
And a reflecting mirror 54 surrounding it and the light guide plate 52, and no reflecting surface is provided.

FIG. 10B is a diagram showing the directional distribution characteristics of the light guide plate front end side and the light source side in this case, the solid line 406 shows the front end side characteristic, and the broken line 407 shows the light source side characteristic. There is.

As shown in the figure, when no reflecting surface is provided, the width of directivity hardly changes between the tip side and the light source side, but as shown by the broken line 407, the amount of emitted light on the light source side is small. It can be seen that there are many small and small angle components.

FIGS. 8A and 8B are views showing the directivity of the light guide plate (No. 2), FIG. 8A is a perspective view, and FIG. 8B is a view showing the relationship between the emission angle of the light beam and the relative luminance. .

In FIG. 9A, reference numeral 53 is a reflecting surface provided below the light guide plate 52 so as to face the back surface 52b. The angle θ is set to 10 °.

In the figure, a fluorescent tube 51 serving as a light source.
And a reflecting mirror 54 surrounding it, the light guide plate 52, and the light guide plate 5
2B, which is composed of the reflection surface 53 provided below the reference numeral 2, is a diagram showing the respective directional distribution characteristics when the reflection surface 53 is a mirror surface and when it is a diffuse reflection surface.
Reference numeral 8 shows the characteristic when the reflecting surface 53 is a mirror surface, and broken line 409 shows the characteristic when the reflecting surface 53 is a diffuse reflecting surface.

As shown in the figure, when the reflecting surface 53 is a mirror surface, the peak of the brightness is the same as when no reflection peak is provided as shown by the solid line 408, but the width of the directivity becomes large. You can see that This is because the light beam emitted from the rear surface 52b of the light guide plate 52 is steeply emitted by the angle θ formed by the emission surface 52c and the rear surface b.
Further, when the reflecting surface 53 is a diffuse reflecting surface, it can be seen that although the peak of the luminance is lowered as shown by the broken line 409, the range of directivity is widened. This is because the emitted light 59 is dispersed and emitted from each part of the emission surface 52c, and the luminance distribution on the light emitting surface is improved.

9A and 9B are views showing the directional characteristic of the light guide plate (No. 3). FIG. 9A is a perspective view, and FIG. 9B is a view showing the relationship between the emission angle of the light beam and the relative luminance. .

In FIG. 10A, reference numeral 55 denotes a transparent diffuse reflection sheet which is arranged between the back surface 52b of the light guide plate 52 and the reflection surface 53 and on which a weighted diffusion reflection pattern is printed. The angle θ is set to 10 °.
In the figure, a fluorescent tube 51 that serves as a light source, a reflecting mirror 54 that surrounds it, a light guide plate 52, and a reflecting surface 53 that is a mirror surface.
And a diffuse reflection sheet 55 disposed between the back surface 52b of the light guide plate 52 and the reflection surface 53.

FIG. 10B is a diagram showing the directional distribution characteristic when the diffuse reflection sheet 55 is arranged between the back surface 52b of the light projecting plate 52 and the reflection surface 53 which is a mirror surface, and is indicated by a solid line 410.
The characteristics are shown in. As shown in the figure, the diffuse reflection sheet 5 is provided between the back surface 52 b of the light guide plate 52 and the reflection surface 53.
In the case where No. 5 is provided, the peak of the luminance is lowered as shown by the solid line 410, but the width of the directivity is increased, as in the broken line 409 when the reflecting surface 53 in FIG. 8 is the diffuse reflecting surface. You can see that This is because the emitted light 59 is dispersed and emitted from each part of the emission surface 52c, and the luminance distribution on the light emitting surface is improved.

FIG. 10 is a diagram (No. 4) showing the directional characteristics of the light guide plate, FIG. 10A is a perspective view, and FIG. 10B is a diagram showing the relationship between the emission angle of the light beam and the relative luminance. .

In FIG. 10A, reference numeral 56 denotes the fluorescent tube 51 in the axial direction between the back surface 52b of the light guide plate 52 and the reflecting surface 53.
It is a linear prism plate that is arranged with the uneven surface facing the light guide plate 52 side so as to be parallel to the longitudinal direction of the. The angle θ is set to 10 °. In the figure, a fluorescent tube 51 that serves as a light source, a reflecting mirror 54 that surrounds it, a light guide plate 52, a reflecting surface 53 that is a mirror surface, and a rear surface 52 b of the light guiding plate 52 and a reflecting surface 53 are provided. And a linear prism plate 56.

FIG. 11B is a diagram showing the directional distribution characteristics when the linear prism plate 56 is arranged between the back surface 52b of the light guide plate 52 and the reflecting surface 53 which is a mirror surface.
The characteristics are shown in 1. As shown in the figure, when the linear prism plate 56 is arranged between the back surface 52b of the light guide plate 52 and the reflecting surface 53, the brightness is improved as indicated by the solid line 411 and the amount of light emitted from the light source side is increased. It can be increased and the brightness distribution is also improved.

FIG. 11 is a diagram (No. 5) showing the directional characteristics of the light guide plate. FIG. 11 (a) is a perspective view, and FIG. 11 (b) is a diagram showing the emission angles in the upper and left and right directions of the light beam and the different brightness. It is a figure which shows a relationship.

In FIG. 9A, reference numeral 57 denotes the fluorescent tube 5 in the axial direction between the fluorescent tube 51 and the incident surface 52a of the light guide plate 52.
The light guide plate 52 has an uneven surface so as to be perpendicular to the longitudinal direction of the light guide plate 52.
It is a linear prism plate arranged toward the side. Also,
The angle θ is set to 10 °. In the figure, a fluorescent tube 51 that serves as a light source, a reflecting mirror 54 that surrounds it, a light guide plate 52, a reflecting surface 53 that is a mirror surface, and a fluorescent tube 51 and an incident surface 52 a of the light guide plate 52 are provided. And a linear prism plate 57 that has been formed.

FIG. 9B shows the vertical direction (angle α) and the horizontal direction with and without the linear prism plate 57 provided between the fluorescent tube 51 and the incident surface 52a of the light guide plate 52. It is a figure showing the directional distribution characteristic of (angle β), the solid line 412 shows the vertical characteristic when the prism plate 57 is provided, and the broken line 413 shows the vertical characteristic when the prism -357 is not provided, the solid line 414. Shows the horizontal characteristic when the prism plate 57 is provided, and the solid line 415 shows the horizontal characteristic when the prism plate 57 is not provided.
As shown in the figure, the light guide plate 5 has an uneven surface between the fluorescent tube 51 and the incident surface 52a of the light guide plate 52 so that the axial direction of the linear prism plate 57 is perpendicular to the longitudinal direction of the fluorescent tube 51.
The characteristics in the left-right direction when arranged toward the 2 side are the broken line 4
As compared with the case where the linear prism plate 57 shown by 15 is not provided, the width of the directivity is narrowed because the light rays in the left and right directions are narrowed down, and the brightness is improved because the light rays are concentrated.

12A and 12B are views showing a fifth embodiment of the illuminating device according to the present invention, wherein FIG. 12A is a plan view and FIG. 12B is a cross section taken along the line AA 'in FIG. 12A. FIG. 1C is a partial cross-sectional view taken along line BB ′ of FIG.

In the figure, 61 is a fluorescent tube as a light source,
Reference numeral 62 is a light guide plate made of a transparent material, 62a is an incident surface of the light guide plate 62, 62b is a back surface of the light guide plate 62 on which a weighted diffuse reflection pattern is printed, and 62c is a conductive surface formed at an angle θ with the back surface 62b. An exit surface of the light plate 62, a reflection side surface 62d at the end of the light guide plate 62, and a back surface 62 of the light guide plate 62.
b a reflecting surface below, 63a a convex reflecting surface provided in the central portion of the reflecting surface 63, 64 a light emitting surface, 65 a space portion, 66 a reflecting mirror surrounding the fluorescent tube 61, 67 a linear prism plate, 68
Is a diffusion sheet, 69 is a light-shielding portion, and 70 is an illuminating device composed of them.

As shown in FIGS. 10A and 10B, the lighting device 70 of this embodiment has a plurality of unit units, each of which is a unit of the lighting device shown in the first to fourth embodiments. Are arranged in a plane, and four fluorescent tubes 61 serving as light sources are provided on four sides surrounded by a reflecting mirror 66, and four independent fluorescent tubes 61 are provided on the side of the fluorescent tube 61 corresponding to each. A light plate 62 is provided. The shape of each light guide plate 62 is inclined toward the tip side so that the angle formed by the emission surface 62c and the back surface 62b is θ, and the width thereof is narrowed toward the tip side, and the brightness distribution on the back surface 62b. A diffuse reflection pattern weighted in consideration of is printed. Back surface 6 of light guide plate 62
The reflecting surface 63 below 2b is provided with a quadrangular pyramid-shaped convex reflecting surface 63a in the space 65 where the tips of the four light guide plates 62, which are the central portions thereof, face each other. A linear prism plate 67 is arranged on the light emitting surface 64 so that the axial direction of the matrix-like electrodes of a display device (not shown) arranged above the linear prism plate 67 and the axis of the linear prism plate 67 are not orthogonal or parallel. . Furthermore, on the upper part of the linear prism plate 67,
The diffusion sheet 68 is arranged so that the diffuse reflection pattern printed on the back surface 62b of the light guide plate 62 is not visually recognized.

Further, as shown in FIG. 7C, the four light guide plates 62 are such that the light rays propagating through the light guide plates 62 are emitted from the other fluorescent tubes 6.
Each light guide plate 62 is separated so as not to return in one direction, and a space is provided between the individual light guide plates 62 to form a light shielding portion 69. And the light guide plate 5
The end surface of 2 is provided with a reflective side surface 62d so as not to emit a light beam, and the reflective side surface 62d is an inclined surface so that the reflected light proceeds to the light emitting surface 64 side.

The illuminating device 70 shown in the present embodiment is suitable for a large illuminating device requiring high brightness, and a plurality of illuminating devices such as those shown in the first to fourth embodiments are used as a unit. By arranging the unit units in a plane, it is possible to provide a high-luminance illuminating device having a high light ray utilization rate while making the luminance distribution uniform.

Further, as in the present embodiment, the structure in which the light guide plates 62 are separated and the four light guide plates 62 are arranged is advantageous in terms of efficiency, but the light guide plates 62 are integrated without being separated. Even with things, efficiency is improved to some extent.

Further, the number of unit units arranged in a plane is not limited here, and the configuration can be changed according to the required specifications of the illuminating device, such as disposing two unit units facing each other. is there. Further, in this embodiment, a diffuse reflection pattern is printed on the back surface 62b of the light guide plate 62 to make the brightness distribution uniform, but the means for making the brightness distribution uniform is also limited to this embodiment. Instead, it is also possible to use the aforementioned means shown in FIGS.

FIG. 13 is a diagram showing a sixth embodiment of the illuminating device according to the present invention, and is a partial sectional view of the illuminating device.

In the figure, 71 is a fluorescent tube, 72 is a light guide plate, 72a is an incident surface of the light guide plate 72, and 72b is a light guide plate 72.
Is a light emitting surface, 73 is a reflecting surface, 74 is a reflecting mirror, 75 is a diffusing sheet, and 80 is an illuminating device including them.

As shown in the figure, the illumination device 8 of the present embodiment.
In the case of 0, a plurality of unit units are vertically arranged with the lighting device as shown in the first to fourth embodiments as a unit unit, and the side surface of the light guide plate 72 and the reflection surface 73 in the unit are arranged adjacent to each other. The light emitting surface is a surface facing the fluorescent tube 71. In addition, the emission surface 72b and the reflection surface 7 of the light guide plate 72
The angle θ with 3 is 30 °, and the light guide plate 72 is made of acrylic resin. A diffusion sheet 75 is arranged on the light emitting surface side so that the luminance distribution is uniform and the reflection surface 73 is not visible, and the light guide plate 72 of one unit unit is arranged.
Of the emitted light emitted from the emission surface 72b of the above, other than the light that directly reaches the diffusion sheet 75, the light is reflected by the reflection surface 73 of the adjacent unit unit and proceeds to the diffusion sheet 75.

The illuminating device 80 shown in this embodiment is suitable for a large illuminating device which requires high brightness. A plurality of illuminating devices as shown in the first to fourth embodiments are used as a unit. By arranging the unit units vertically, it is possible to provide a high-luminance illuminating device having a uniform luminance distribution, a high light ray directivity, and a high light ray utilization rate.

FIG. 14 is a diagram showing a seventh embodiment of the illuminating device according to the present invention and is a partial sectional view of the illuminating device.

In the figure, 71 'is a fluorescent tube, 72' is a light guide plate, 72a 'is an entrance surface of the light guide plate 72', 72b 'is an exit surface of the light guide plate 727, 73' is a reflection surface, and 74 'is a reflection surface. A mirror, 75 'is a diffusion sheet, and 80' is a lighting device composed of them.

As shown in the figure, the illumination device 8 of the present embodiment.
0 ′ is different from the seventh embodiment in the shape of the light guide plate 72 ′, and the light guide plate 72 ′ is formed so that the cross-sectional shape thereof is a substantially isosceles triangle, and two emission surfaces 72b ′ are provided by inserting the apex angle. Has been. The apex angle θ is 30 ° as in the sixth embodiment.
Is.

The illuminating device 80 'shown in this embodiment can be a high-luminance illuminating device in which the directivity of light rays is further improved as compared with the sixth embodiment and the light ray utilization rate is high.

FIG. 15 is a diagram showing an eighth embodiment of the illuminating device according to the present invention and is a partial sectional view of the illuminating device.

In the figure, 71 "is a fluorescent tube, 72" is a light guide plate, 72a "is an incident surface of the light guide plate 72", 72b "is an exit surface of the light guide plate 72", 73 "is a reflection surface, and 74" is 74 ". A reflecting mirror, 75 "is a diffusion sheet, and 80" is an illuminating device composed of them.

As shown in the figure, the illumination device 8 of this embodiment
0 "differs from the sixth and seventh embodiments in the method of arranging the unit units, and the unit units are laminated obliquely so that the side surface of the light guide plate 72" in the unit and the reflection surface 73 "are adjacent to each other, The emitting surface 72b ″ of the light guide plate 72 ″ serves as a light emitting surface. Further, the apex angle θ is 30 as in the sixth embodiment.
°.

The illumination device 80 "shown in this embodiment can be made thinner than the sixth and seventh embodiments.
It is possible to provide a thin lighting device having a high light ray utilization rate and high brightness.

16 and 17 show an illumination device 100 according to the ninth embodiment of the present invention.

The illumination device 100 is the illumination device 70 of FIG.
The lighting device 70 of FIG. 12 is different from the lighting device 70 of FIG. 12 in the following points.

Structure of the diffusion pattern 101 on the back surface of the light guide plate.

The special linear prism plate 102 is arranged between the light guide plate and the normal linear prism plate.

16 and 17, reference numeral 105 denotes a fluorescent tube as a linear light source. Reference numeral 106 denotes a light guide plate, which is an incident surface 1
06a, the horizontal back surface 106b, and the exit surface 106c. 106d is a tip. The light guide plate 106 has an incident surface 1
The emission surface 106c, which has a thickness t that becomes smaller as it goes away from 06a, is an inclined surface that forms an angle θ with the back surface 106b. The light guide plate 106 has a wedge shape and has a cross section of a right triangle. Reference numeral 107 denotes a reflector, which is the light guide plate 10.
It is arranged on the lower side of 6. Reference numeral 108 is a reflecting mirror surrounding the fluorescent tube 105. Reference numeral 109 denotes a space, which exists above the inclined emission surface 106c of the light guide plate 106 and in front of the tip 106d.

110 is a normal linear prism plate,
It is arranged above the light guide plate 106, and the space 1 is provided below it.
09 are formed. Normal linear prism plate 110
18 has a structure in which roof-shaped linear prisms 111 having an apex angle of 90 degrees are aligned, as shown in FIG. As shown in FIG. 18, the normal linear prism plate 110 is oriented such that the surface on which the linear prism 111 is formed is the upper surface, and the longitudinal direction of the linear prism 111 is the fluorescent tube 105.
Is arranged at an angle α with respect to the direction (represented by the line 112) orthogonal to. As shown in FIG. 18, the normal linear prism plate 110 allows the incident light 113 having a large divergence to enter the normal line 1 of the normal linear prism plate 110.
It acts so as to collect and emit in the direction of 14. The degree of collection of the emitted light 115 is about ± 40 degrees.

Reference numeral 116 denotes a diffusion sheet, which is usually arranged on the upper surface side of the linear prism plate 110 and diffuses the light from the normal linear prism plate 110. Diffusion sheet 116
The upper surface of the is the light emitting surface 117 of the lighting device 100.

Next, the characteristic structure of the illumination device 100 will be described.

First, the diffusion pattern 101 will be described.

The diffusion pattern 101 has a structure in which a small portion coated with white ink, that is, a small division portion 120 coated with white ink as a diffusion element is arranged in a predetermined pattern. The light rays that have entered the white ink application small section 120 are diffused. The white ink application small section 120 is
As shown by the line I in FIG. 19, the back surface 106 of the light guide plate 106.
It is formed with a particularly high density in the vicinity of the incident surface 106a of b. In other words, the white ink application small section 120 is formed by weighting so that the printing area is particularly large in the vicinity of the incident surface 106a of the light guide plate 106. The diffusion pattern 101 acts so as to diffuse a particularly large amount of light particularly near the incident surface 106a.

Next, the special linear prism plate 102 will be described.

As shown in FIG. 20, the special linear prism plate 102 has three roof-shaped linear prisms 121 having an apex angle of 140 degrees, and a roof-shaped linear prism 121 having an apex angle of 70 degrees. The prism 122 has a structure in which the prisms 122 are aligned at a certain ratio. As shown in FIGS. 16 and 17, the special linear prism plate 102 is oriented with the surface on which the linear prisms 121 and 122 are formed as the lower surface, and the linear prism 1
21 (122) has a longitudinal direction orthogonal to the line 112, that is, a direction parallel to the fluorescent tube 105, above the light guide plate 106, and below the normal linear prism plate 110. It is provided in. An air layer 129 exists between the normal linear prism plate 110 and the special linear prism plate 102.

As shown in FIG. 20, the linear prism 122 having an apex angle of 70 degrees acts to totally reflect the incident light beam 123 and transmit it upward as indicated by reference numeral 124. The linear prism 121 having an apex angle of 140 degrees enters the linear prism 121 so that the incident light beam 125 is incident on the upper surface 102a of the special linear prism plate 102 at a critical angle or more, and the incident light beam 126 is The light beam 127 reflected by the upper surface 102a and totally reflected by the upper surface 102a is directed toward the center of the illuminating device 100 obliquely downward from the linear prism plate 102, as indicated by reference numeral 128.
The light is emitted to the inside of the optical element 9 and returned to the inside of the space 109, that is, the light is propagated in the surface direction of the special linear prism plate 102.

Here, the linear prism 121 is the fluorescent tube 1
The direction is parallel to 05. Therefore, the above light 1
28 is efficiently oriented towards the center of the lighting device 100. That is, the special linear prism 102 is used as the lighting device 1.
00, the longitudinal direction of the linear prism 121 (122) is set to be parallel to the fluorescent tube 105 in order to improve the light propagating property toward the center.

Next, the operation of the illumination device 100 having the above structure will be described with reference to FIG.

In FIG. 21, the arrow indicates a light beam, and the thickness of the arrow indicates the light quantity. The thicker the arrow, the larger the light quantity. Light 130 from the fluorescent tube 105 enters the light guide plate 106 from the incident surface 106 a and goes toward the tip 106 d of the light guide plate 106.
Due to the distribution of the diffusion pattern 101, most of the light that has entered the light guide plate 106 is diffused near the incident surface 106a. As a result, a large amount of light 131 is emitted from the vicinity of the incident surface 106a on the emission surface 106b. The remaining light 132 propagates toward the tip 106d of the light guide plate 106. The light amount of the light 132 is originally small, and the light 133 and 134 are emitted from the emission surface 106b while being diffused even during the propagation.
5, 136, the amount of light 137 emitted from the tip 106d is small. This solves the problem that the part of the light emitting surface 117 corresponding to the tip 106d of the light guide plate 106 becomes particularly bright.

The light 131 is incident on the special linear prism plate 102. Special linear prism plate 102
Of the light incident on the inside, only a part of the light 140 is transmitted and emitted upward, and the remaining light 141 is reflected and reflected by the space portion 1.
It is returned in 09.

Regarding the lights 133 and 134, only some of the lights 142 and 143 are included in the special linear prism plate 102.
The remaining light 144, 145 is transmitted through the inside and emitted upward.
Are reflected back into the space 109. Space part 10
The light 141, 144, 145 returned to the inside 9 is reflected by the emitting surface 106c of the light guide plate 106, enters the special linear prism plate 102 again, and part of the light is transmitted and emitted upward. , The rest is reflected and returned to the inside of the space 109 again.

The above operation is repeated, and a substantially constant amount of light is emitted from the upper surface 102a of the special linear prism plate 102 over the entire surface of the special linear prism plate 102. Therefore, as will be described later, the light emitting surface 117 has uniform brightness over the entire surface.

The light emitted above the special linear prism plate 102 normally enters the linear prism plate 110,
As indicated by reference numeral 145, the light is condensed and emitted in the normal direction, is further diffused by the diffusion sheet 116, and is emitted from the light emitting surface 117 as indicated by reference numeral 146.

As a result, the light emitting surface 11 of the illuminating device 100.
7 is a portion corresponding to the tip 106d of the light guide plate 106,
A high brightness portion does not appear as compared with the periphery thereof, and a high brightness portion does not appear even in a portion close to the fluorescent tube 105, and a good brightness distribution is obtained in which the brightness is substantially constant over the entire surface.

Next, characteristics of the liquid crystal display device when the above lighting device 100 is used as a backlight of a liquid crystal panel will be described.

In FIG. 17, reference numeral 150 denotes a liquid crystal panel, which is arranged above the lighting device 100.

The liquid crystal panel 150 has an X-axis extending in the X-direction.
It has a direction display electrode 151 and a Y direction display electrode 152 extending in the Y direction.

In FIG. 17, a line 112 orthogonal to the fluorescent tube 105 extends in the X direction.

Here, the positional relationship of the linear prisms 111, 121, 122 with respect to the display electrodes 151, 152 when viewed from the front of the liquid crystal display device will be examined.

The linear prism 111 and the linear prism 12
It intersects with 1,122 at an angle of (90-α). Therefore, the linear prism 111 and the linear prisms 121, 1
It does not easily interfere with 22 and moire fringes do not occur.

The linear prism 111 and the display electrode 15
It intersects with 1,152 at about 45 degrees. Therefore, the linear prism 111 and the display electrodes 151 and 152 are less likely to interfere with each other, and moire fringes do not occur.

Next, a modification of the ninth embodiment will be described.

The ratio between the linear prism 121 and the linear prism 122 of the special linear prism plate 102 in FIGS. 16 and 17 may be set to a ratio other than 3: 1, such as 4: 1.

FIG. 22 shows a special linear prism plate 102A in which the ratio between the linear prism 121 and the linear prism 122 is 4: 1.

The prism plate 102A propagates more light in the surface direction than the prism plate 102 described above.

Further, instead of the special linear prism plate 102, a special lenticular plate 160 shown in FIG.
A configuration may be adopted in which the surface of the semicylindrical lens is provided so as to face downward.

The height of the special lenticular plate 160 is h.
1, the three semi-cylindrical lenses 161 having a radius r1 and the semi-cylindrical lens 162 having a height h2 and a radius r2.
Is a structure that is aligned at one ratio. h2> h1, r2
> R1.

As can be seen from the path of the light ray 163, the semi-cylindrical lens 162 acts to transmit the light ray upward. As can be seen from the path of the light ray 164, the semicylindrical lens 161 acts to return the light ray downward, that is, to propagate the light in the surface direction of the special lenticular plate 160.

Next, an illumination device 200 according to the tenth embodiment of the present invention will be described with reference to FIG.

In the tenth to twentieth embodiments, the rear surface of the light guide plate is devised so that the luminance distribution is made uniform.

In FIG. 24, 201 is a fluorescent lamp as a linear light source. Reference numeral 202 denotes a light guide plate, which has a back surface 202a and an exit surface 202b that are both horizontal, and an entrance surface 202c and a tip surface 202d that are both vertical. Reference numeral 203 denotes a reflecting plate, which is arranged on the rear surface 202a side of the light guide plate 202. Reference numeral 204 denotes a reflecting surface, which is an upper surface of the reflecting plate 203. A reflecting mirror 205 surrounds the fluorescent lamp 201. Reference numeral 206 denotes a light emitting surface of the lighting device 200. Reference numeral 207 denotes a groove forming an essential part of the present invention, which is a rear surface 20 of the light guide plate 202.
2a extend in a direction parallel to the incident surface 202c (direction perpendicular to the paper surface in the figure), and a large number of them are aligned. Groove 2
In the rear surface 202a, the central portion 202a-1 is aligned at the pitch P1 in the rear surface 202a, and the pitch becomes narrower as it is deviated from the central portion 202a-1, and the portion 202a-2 closer to the incident surface and the portion 202a closer to the front end surface 202a. -3,
It is arranged in a distribution in which the pitch P2 is narrower than the pitch P1.

As shown in an enlarged view in FIG. 25, the groove 207 has a triangular shape and is composed of two inclined planes 208 and 209. Both the inclined planes 208 and 209 are inclined at a predetermined angle θ with respect to the horizontal plane. The angle θ is about 30 degrees,
The angle is such that the incident light is not returned to the fluorescent lamp 201 side.

Here, the function of the groove 207 will be described.

The light is emitted from the fluorescent lamp 201, and the incident surface 202c
A part of the light that has entered the light guide plate 202 is further directed to the groove 207. The light directed to the groove 207 can be classified into three types of light rays 210, 211, and 212 depending on the angle at which it strikes the inclined plane 208. The light ray 210 is totally reflected by the inclined plane 208 and becomes a light ray 210a toward the emission surface 202b. Ray 21
1 goes into the groove 207, is reflected by the reflection surface 204 of the reflection plate 203, enters the light guide plate 202 again from the inclined flat surface 209, and becomes a light ray 211a toward the emission surface 202b. The light ray 212 exits into the groove 207, crosses the groove 207, and enters the light guide plate 202 again from the inclined plane 209.
It becomes a and goes toward the front end surface 202d. In this way, the groove 207 acts so as to efficiently direct the light rays traveling in the light guide plate 202 toward the rear surface 202a toward the emission surface 202b.

Conventionally, as shown in Japanese Unexamined Patent Publication No. 2-165504, the grooves corresponding to the above-mentioned grooves 207 are arranged at a uniform pitch over the entire bottom surface of the light guide plate, and the surfaces forming the grooves. The inclination of was a condition that all the light incident on the groove was totally reflected. Therefore, the luminance distribution on the light emitting surface is as shown in FIG.
In the middle, as indicated by the broken line II, the luminance tends to decrease in the portion near the incident surface 202c and the portion near the front end surface 202d.

In this embodiment, since the grooves 207 are arranged in the above distribution, the amount of light traveling toward the emission surface 202b is such that the portion 202a-2 near the incident surface and the portion 202a- near the front end surface. In the case of 3, the brightness is increased as compared with the above-described conventional example, and the brightness of the light emitting surface 206 at the portion near the incident surface and the portion near the front end surface is increased. As a result, the luminance of the light emitting surface 206 of the lighting device 200 is the line III in FIG.
As shown by, it becomes substantially uniform over the entire surface.

FIG. 26 shows an illuminator 220 according to the eleventh embodiment of the present invention. In the figure, the same components as those shown in FIG. 24 are designated by the same reference numerals.

In the light guide plate 202A, the groove 207 is
They are distributed at the same pitch P3 in the area near the fluorescent lamps 201 on the back surface 202a. The grooves 207 are numbered 207-1, 207-2, ... From the side closer to the incident surface 202Ac. The U-shaped reflecting mirror 205A extends to the groove 207-1. Reference numeral 205Aa denotes an upper covering portion as a reflecting mirror portion, and a portion 202 of the emission surface 202Ab of the light guide plate 202A corresponding to the groove 207-1 near the incident surface 202Ac.
Covers Ab-1. 205Ab is a lower covering portion, and is a groove 207 on the back surface 202Aa of the light guide plate 202A.
-1 is covered. 202A-1 of the light guide plates 202A
Is a light emitting region. 202A-2 is a light accumulation region, which accumulates light as described later. Emitted from the fluorescent lamp 201,
Light 2 incident on the light guide plate 202A from the incident surface 202Ac
21 is reflected by the surface of the groove 207-1 as shown by the reference numeral 221a, and is directed toward the surface 202Ab-1 toward the surface 202Ab-.
Although it is emitted from No. 1, it is reflected by the upper cover portion 205Aa and enters the light guide plate 202A. This light is on the back side 202A
Even if the light is emitted from the rear surface 202Aa toward the side a, it is reflected by the lower cover portion 205Ab and is again guided to the light guide plate 202A.
Go inside and turn upward. The light repeats this and proceeds in the direction of the light emitting region 202A-1.

The upper cover portion 20 of the emission surface 202Ab
The portion not covered with 5Aa is the effective emission surface 202Ab.
-2. On the effective emission surface 202Ab-2, as in the case of the tenth embodiment, the light reflected or refracted by the grooves 207-2 to 207-5 and directed upward is emitted. Looking at the portion of the effective emission surface 202Ab-2 near the fluorescent lamp 201, the light 222 refracted by the groove 207-2 is reflected.
In addition, light 221b leaking from the light accumulation region 202A-2 and traveling upward is added, and the amount of light in this portion increases. As a result, the luminance of the light emitting surface 206 of the lighting device 220 is reduced to the line IV.
As shown in, the area becomes substantially uniform in the region near the fluorescent tube.

FIG. 27 shows an illumination device 230 according to the twelfth embodiment of the present invention. This lighting device 230 has a configuration in which the lighting device 200 of FIG. 24 and the lighting device 220 of FIG. 26 are combined. In FIG. 27, parts corresponding to the parts shown in FIGS. 24 and 26 are designated by the same reference numerals.

The groove 207-1 and the upper covering portion 205Aa as the reflecting mirror portion form the light storage region 202A-2. In the portion of the effective emission surface 202Ab-2 closer to the fluorescent lamp 201, the light 222 reflected and refracted by the grooves 207-2 and 207-3 leaks upward from the light accumulation region 202A-2 to the light 221b. Is added. Where the groove 207-
Since the pitch P2 of 1,207-2 is small,
The light intensity of 2 is large. Accordingly, the brightness of the light emitting surface 206 is
As shown by the line V in FIG. 27, it becomes uniform over the entire surface.

FIG. 28 shows an illumination device 240 according to the thirteenth embodiment of the present invention. The illumination device 240 has a configuration in which the light guide plate 202 of the illumination device 200 of FIG. 24 is changed. In FIG. 28, parts corresponding to the parts shown in FIG. 26 are designated by the same reference numerals.

The light guide plate 241 is generally formed by forming the light guide plate 202 into a wedge shape in section, and has an inclined emission surface 241b and a curved front end surface 241c. Reference numeral 241a denotes a horizontal back surface, in which a groove 207 is formed. 241c is a vertical incident surface.

Here, the reason why the tip end surface 241c can be a curved surface is that the light exit surface 241b is an inclined surface and the light guide plate 202 has a wedge shape.

Since the tip surface 241c is a curved surface, the light propagating through the light guide plate 241 and reaching the tip is reflected toward the light source side as compared with the case where the tip is a vertical plane as shown in FIG. It is difficult to be discharged, and most of them are discharged upward from the tip surface 241c as indicated by reference numeral 242. This allows
Light is also efficiently emitted from the portion of the light guide plate 241 near the tip, and the brightness of the tip of the light emitting surface 243 is increased. The luminance of the light emitting surface 243 becomes uniform over the entire surface as indicated by a line VI in FIG.

FIG. 29 shows an illumination device 250 according to the fourteenth embodiment of the present invention. In the figure, parts corresponding to the parts shown in FIG. 24 are designated by the same reference numerals.

The illumination device 250 has a light guide plate 251. As shown in FIG. 30, the light guide plate 251 has a pit group 252 on the back surface 251a. Pit group 252
Consists of a number of pits 253. Each pit 253
It has a triangular cross section and, like the groove 207 in FIG. 24, directs the light propagating in the light guide plate 251 and reaching the rear surface 251a toward the emission surface 251b. The pit group 252 includes a pit row 254-having pitches 253-1 to 253/4 arranged side by side.
1, a pit row 254-2 composed of aligned pits 253-5 to 253-7, and a pit row 254-3 composed of aligned pits 253-8 to 253-11 are aligned in parallel and between adjacent pit rows The pits are arranged in a staggered pattern. As a result, as compared with the case where the groove 207 is formed on the back surface as shown in FIG.
The amount of light directed to 1b is made more uniform over the entire back surface.

As a result, the light emitting surface 25 of the lighting device 250 is
No. 5 suppresses uneven brightness corresponding to the groove streak as compared with the illumination device 200 of FIG. 24, and as shown by a line VII in FIG.
It has a uniform luminance distribution over the entire surface.

FIG. 31 shows an illuminating device 260 according to the fifteenth embodiment of the present invention. In the figure, parts corresponding to the parts shown in FIG. 24 are designated by the same reference numerals.

The illumination device 260 has a light guide plate 261. The light guide plate 261 is, as shown in FIGS. 32 and 33,
A groove group 262 having a triangular cross section is provided on the back surface 261a.
The groove group 262 includes a groove 262a forming an acute angle α1 with respect to a line 264 orthogonal to the axis 263 of the fluorescent lamp 201, and the line 2 described above.
The groove 262b forms an obtuse angle α2 with respect to 64. The groove 262a and the groove 202b intersect at many points. Therefore, groove streaks are less likely to appear as compared with the illumination device 200 of FIG. 24 in which the grooves are arranged in parallel. Therefore, the illumination device 260 has a uniform luminance distribution over the entire surface, as indicated by the line VIII in FIG.

FIG. 34 shows an illumination device 270 according to the 16th embodiment of the present invention. In the figure, parts corresponding to the parts shown in FIG. 24 are designated by the same reference numerals.

The illumination device 270 has a light guide plate 271. The light guide plate 271 has a groove group 271 on the back surface 271a. The groove group 271 includes grooves 272 to 277. Groove 2
72 to 277 are larger in size as they come closer to the fluorescent lamp 201. The pitch P4 of the grooves 272 to 277 is constant and smaller than the pitch P1 in FIG. Therefore, in the illumination device 270, groove streaks are less likely to appear and the amount of emitted light is the same as in the device 200 of FIG. 24, and line IX in FIG.
As shown by, the luminance distribution is uniform over the entire surface.

FIG. 35 shows an illumination device 280 according to the seventeenth embodiment of the present invention. In the figure, parts corresponding to the parts shown in FIG. 24 are designated by the same reference numerals.

The lighting device 280 has a light guide plate 281. As shown in FIG. 36, the light guide plate 281 has a pit group 282 on the back surface 281a. Pit group 282
Consists of a number of pits 283. Each pit 283 is
It has a triangular cross section and, like the groove 207 in FIG. 24, directs the light propagating in the light guide plate 281 and reaching the rear surface 281a toward the emission surface 281b. Pit group 282 is pit 2
The diagonal pit row 284 in FIG.
And a diagonal pit row 285 in the upper right corner. The pit row 284 intersects with the pit row 285. As a result, as compared with the case where the groove 207 is formed on the rear surface as shown in FIG. 24, the amount of light directed from the rear surface 281a side to the emission surface 281b is made more uniform over the entire rear surface.

As a result, the light emitting surface 28 of the lighting device 280 is
24, luminance unevenness corresponding to the groove streaks is suppressed as compared with the illumination device 200 of FIG. 24, and as shown by a line X in FIG. 35, a uniform luminance distribution is provided over the entire surface.

FIG. 37 shows an illuminator 290 according to the eighteenth embodiment of the present invention. In the figure, parts corresponding to the parts shown in FIG. 24 are designated by the same reference numerals.

The illumination device 290 has a light guide plate 291. The light guide plate 291 has a groove 292 having a triangular cross section on the back surface 291a. The angle θ10 with respect to the extension surface of the opposite surface 291a of the groove 292 is set to be considerably smaller than the angle θ11 in FIG. If the angle θ10 is small, the groove 2
The ability of 92 to direct light to the exit surface 291b is small. Thus, by changing the angle θ10 of the groove 292,
The amount of light emitted from the emission surface 291b can be changed.

FIG. 38 shows an illumination device 300 according to the nineteenth embodiment of the present invention. The light guide plate 310 has a back surface 301a.
In addition, it has a U-shaped groove 302.

FIG. 39 shows an illumination device 310 according to the twentieth embodiment of the present invention. The lighting device 310 includes a light guide plate 311 and a reflection plate 312. The light guide plate 311 has a back surface 311a having grooves 318 with a uniform pitch. A reflecting plate 312 has a large number of protrusions 313 on the upper surface facing the back surface 311a. The ridges 313 are the light guide plates 311.
The light 314 leaked from the groove 318 of the back surface 311a is reflected, and as shown by the reference numeral 314a, is made incident on the light guide plate 311 again and is directed to the emission surface 311b.

The ridges 313 are aligned at the pitch P10 with respect to the central portion 314, and the pitch becomes narrower as they deviate from the central portion 314, and the portion 3 near the incident surface 311c.
15 and the portion 316 near the tip surface 311d are arranged in a distribution aligned at a pitch P11 narrower than the pitch P11.

Of the light leaked from the groove 318 of the back surface 311a of the light guide plate 311, the light leaked from the vicinity of the incident surface 311c and the light leaked from the vicinity of the tip surface 311d are the light leaked from the central portion. The light is more efficiently returned to the inside of the light guide plate 311 and emitted from the light emitting surface 317. Therefore, the luminance distribution of the light emitting surface 317 is as shown in FIG.
As shown by the line XI, it becomes substantially uniform over the entire surface.

[0168]

As described above, according to the first aspect of the invention, in the light guide plate, the grooves are arranged at a narrower pitch in the portions near the incident surface and the tip surface than in the central portion. In the portion close to the incident surface and the portion close to the front end surface, the amount of light traveling toward the emission surface is increased, so that a uniform luminance distribution can be obtained over the entire light emitting surface.

According to the second aspect of the present invention, the reflecting mirror portion works so as to cooperate with the groove to form a portion for accumulating light. The portion where the light is accumulated acts so as to be emitted from the reflecting mirror portion of the emission surface that emits a part of the light, and thus,
A uniform luminance distribution can be obtained over the entire light emitting surface.

According to the third aspect of the present invention, the grooves are arranged at a narrower pitch in the portions near the incident surface and the tip end surface than in the central portion. In the portion near the tip surface, it acts to increase the amount of light directed to the emission surface, and the reflecting mirror portion acts in cooperation with the groove to form a portion that accumulates light. Has a function of causing the light to be emitted from the reflecting mirror portion of the emission surface that emits a part of the light, and thereby efficiently enhances the luminance of the portion of the light emitting surface where the luminance tends to decrease and which is closer to the light source. It is possible to obtain a uniform luminance distribution over the entire light emitting surface.

According to the fourth aspect of the present invention, the configuration in which the front end surface is a curved surface makes it difficult for light propagating in the light guide plate and reaching the front end to be reflected to the light source side, and emits all the light. As a result, it is possible to effectively improve the luminance of the portion of the light emitting surface on the side opposite to the light source, and to obtain a uniform luminance distribution over the entire light emitting surface. You can get it.

According to the fifth aspect of the present invention, the element for directing the light in the direction of the emission surface is a pit having a triangular cross section, and the pits are arranged in a zigzag pattern. And the brightness unevenness on the light emitting surface can be effectively prevented.

According to the sixth aspect of the present invention, the structure in which a large number of grooves are arranged so as to intersect with each other acts to make the groove stripes less visible, and thus a light emitting surface without uneven brightness can be realized.

According to the invention of claim 7, the structure in which the size of the groove is changed acts so as to make it possible to narrow the pitch of the groove, and the narrow pitch of the groove shows the groove stripe. It acts so as not to be easily exposed, and thus a light emitting surface without uneven brightness can be realized.

According to the eighth aspect of the present invention, the element for directing the light toward the emission surface is a pit having a triangular cross section, and the pit rows in which the pits are arranged intersect with each other. It acts so as not to generate a groove streak, which can effectively prevent uneven brightness on the light emitting surface.

According to the ninth aspect of the invention, the reflection plate is provided with a large number of ridges and the rear surface of the light guide plate is provided with grooves having a uniform pitch, so that the luminance of the light emitting surface does not become uneven. In addition, the configuration in which the distribution of the ridges has a narrower pitch in the portion near the incident surface and the tip surface than in the central portion, is that the portion near the incident surface and the portion near the tip surface are temporarily It leaks from the back surface and then acts to increase the amount of light that enters the light guide plate and faces the emission surface, whereby the back surface of the light guide plate is covered with grooves of uniform pitch over the entire light emitting surface. A uniform brightness distribution can be obtained.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of an illumination device related to the present invention.

FIG. 2 is an operation explanatory diagram of an illumination device related to the present invention.

FIG. 3 is a diagram showing a first embodiment of a lighting device according to the present invention.

FIG. 4 is a diagram showing a second embodiment of the lighting device according to the present invention.

FIG. 5 is a diagram showing a third embodiment of the lighting device according to the present invention.

FIG. 6 is a diagram showing a fourth embodiment of the lighting device according to the present invention.

FIG. 7 is a diagram (No. 1) showing directional characteristics of a light guide plate.

FIG. 8 is a diagram showing a directional characteristic of the light guide plate (No. 2).

FIG. 9 is a diagram showing a directional characteristic of the light guide plate (No. 3).

FIG. 10 is a diagram (No. 4) showing the directional characteristics of the light guide plate.

FIG. 11 is a diagram (No. 5) showing the directional characteristics of the light guide plate.

FIG. 12 is a diagram showing a fifth embodiment of the lighting device according to the present invention.

FIG. 13 is a diagram showing a sixth embodiment of the lighting device according to the present invention.

FIG. 14 is a diagram showing a seventh embodiment of the lighting device according to the present invention.

FIG. 15 is a diagram showing an eighth embodiment of the lighting device according to the present invention.

FIG. 16 is a view showing a ninth embodiment of the lighting device according to the present invention.

17 is an exploded perspective view of the lighting device of FIG.

FIG. 18 is a partially enlarged view of the normal linear prism plate in FIGS. 16 and 17.

FIG. 19 is a diagram illustrating a diffusion pattern on the back surface of the light guide plate.

FIG. 20 is a partially enlarged view of the special linear prism plate in FIGS. 16 and 17.

FIG. 21 is a diagram illustrating the operation of the lighting device in FIG. 16.

FIG. 22 is a diagram showing a modified example of a special linear prism plate.

FIG. 23 is a partially enlarged view of the special lenticular plate.

FIG. 24 is a view showing a tenth embodiment of the lighting device according to the present invention together with its luminance distribution.

FIG. 25 is a view for explaining the action of the groove in FIG. 24.

FIG. 26 is a diagram showing an eleventh embodiment of a lighting device according to the present invention together with its luminance distribution.

FIG. 27 is a view showing a twelfth embodiment of the lighting device according to the present invention together with its luminance distribution.

FIG. 28 is a diagram showing a thirteenth embodiment of a lighting device according to the present invention together with its luminance distribution.

FIG. 29 is a diagram showing a fourteenth embodiment of a lighting device according to the present invention together with its luminance distribution.

FIG. 30 is a diagram showing an arrangement of pit groups on the back surface of the light guide plate in FIG. 29.

FIG. 31 is a view showing a fifteenth embodiment of the lighting device according to the present invention together with its luminance distribution.

32 is a view of the light guide plate in FIG. 31 as viewed from the back side.

33 is an enlarged perspective view showing a part of the back surface of the light guide plate of FIG. 32. FIG.

FIG. 34 is a diagram showing a sixteenth embodiment of a lighting device according to the present invention together with its luminance distribution.

FIG. 35 is a diagram showing a seventeenth embodiment of a lighting device according to the present invention together with its luminance distribution.

36 is a view of the light guide plate in FIG. 35 as viewed from the back side.

FIG. 37 is a diagram showing an eighteenth embodiment of a lighting device according to the present invention.

FIG. 38 is a diagram showing a nineteenth embodiment of a lighting device according to the present invention.

FIG. 39 is a diagram showing a twentieth embodiment of an illumination device according to the present invention together with its luminance distribution.

FIG. 40 is a diagram showing a conventional lighting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 light source 2 light guide plate 2a incident surface 2b back surface 2c emitting surface 3 reflecting surface 3a side wall surface 4 light emitting surface 5 space 6 reflecting mirror 7 propagating light 8 emitting light 10 lighting device 100 lighting device 101 diffusion pattern 102, 102A special linear prism plate 102a Upper surface 105 Fluorescent tube 106 Light guide plate 106a Incident surface 106b Rear surface 106c Emission surface 106d Tip 107 Reflector 108 Reflector 109 Space 110 Normal linear prism plate 111 Linear prism 112 Line 113 orthogonal to fluorescent tube 113 Incident light 114 method Line 115 Emitted light 116 Diffusion sheet 117 Light emitting surface 120 White ink application small partition 121 Linear prism 122 having an apex angle of 140 degrees Linear prism 123 having an apex angle of 70 degrees Incident light ray 124 Emitted light ray 125 Incident light ray 126 Incident light ray 128 Totally reflected ray 128 Light returned to the space Line 129 Air layer 131 A large amount of light diffused when entering the light guide plate 141, 144, 145 Light returned to the space 150 Liquid crystal panel 151 X direction display electrode 152 Y direction display electrode 160 Special lenticular plate 161 Kamaboko shape Lens 162 Cylindrical lens 163,164 Rays 200, 220, 230, 240, 250, 260, 2
70, 280, 290, 300, 310 Lighting device 201 Fluorescent lamp 202, 202A, 241, 251, 261, 271,
281, 291, 301, 311 light guide plate 202a back surfaces 202a-1, 314 central portions 202a-2, 315 portions 202a-3, 316 closer to the incident surface portion 202b closer to the front end surface, exit surface 202c incident surface 202d front end surfaces 203, 312 Reflecting surface 204 Reflecting surface 205 Reflecting mirror 205Aa Upper covering portion 205Ab Lower covering portion 206 Light emitting surface 207 Grooves 208, 209 Inclined flat surfaces 210, 211, 212 Rays 241 Inclined emitting surface 241c Tip surface 242 Light emitted from tip surface 252 Pit Group 253 Pits with triangular cross section 254-1, 254-2, 254-3 Pit row 262 Groove group 263 Axis line 264 of fluorescent lamp Line 272-277 orthogonal to axis line of fluorescent lamp Groove 282 Pit group 283 Pit 284, 285 pit Row 286 Light emitting surface 302 U-shaped groove 313 Projection

Continued front page    (72) Inventor Fumiaki Yamada             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Shinpei Nagatani             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Eiji Hito             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited F-term (reference) 2H091 FA16Z FA23Z FA32X FA42Z                       FC14 FD23 LA11 LA18 LA30

Claims (9)

[Claims] 1. A light guide plate (20) having a light source (201), an incident surface (202c) on which a light ray from the light source (201) is incident, and an emission surface (202b) on which the incident light ray is emitted.
2) and a reflection plate (203) arranged on the back surface (202a) side of the light guide plate and reflecting light rays toward the light guide plate, wherein the light guide plate is provided on the back surface (202a) thereof. A plurality of grooves (2) that direct the light incident from the incident surface toward the emission surface.
07), the portion of the back surface closer to the incident surface and the portion closer to the end opposite to the incident surface have a narrower pitch (P2) than the central portion. Lighting device. 2. A light source (201), an incident surface (202Ac) on which a light ray from the light source is incident, an emission surface (202Ab) on which the incident light ray is emitted, and an emission surface (202Ab).
And a back surface (202Aa) facing the light guide plate (20
2A) and the back surface (202Aa) of the light guide plate (202A)
And a plurality of grooves (207-1 to 207-n) for directing light toward the emission surface on the back surface of the light guide plate. And on the exit surface, the grooves (207-1 to 207-n)
An illuminating device characterized in that a reflecting mirror portion (205Aa) covering a portion corresponding to at least one groove near the incident surface is provided. 3. A light guide plate (20) having a light source (201), an incident surface (202c) on which a light ray from the light source (201) is incident, and an emission surface (202b) from which the incident light ray is emitted.
2) and a reflection plate (203) arranged on the back surface (202a) side of the light guide plate and reflecting light rays toward the light guide plate, wherein the light guide plate is provided on the back surface of the light guide plate. A large number of grooves (207-1 to 207-1) that direct the light propagating in the light guide plate toward the emission surface.
207-n) is arranged such that a portion of the back surface closer to the incident surface and a portion closer to the end opposite to the incident surface have a narrower pitch (P2) than the central portion. At the same time, the illumination device is characterized in that a reflection mirror (205Aa) is provided to cover a portion of the emission surface corresponding to the groove near the incidence surface. 4. A light source (201), an incident surface on which a light ray from the light source is incident, and an emission surface on which the incident light ray is emitted.
In a lighting device comprising a light guide plate having a back surface facing the emission surface and a reflection plate (203) arranged so as to face the back surface of the light guide plate, the light guide plate (241) is provided with a back surface ( 241a) is provided with a large number of grooves (207) directed in the direction of the emission surface propagating in the light guide plate, with respect to a portion of the back surface near the incident surface and a portion of the back surface opposite to the incident surface. Is
It is characterized in that it is arranged with a distribution with a narrower pitch (P2) than that in the central portion, and that it has an emission surface (241b) that is an inclined flat surface and a curved tip surface (241c). Lighting equipment. 5. A light source (201), an incident surface on which a light ray from the light source is incident, and an emission surface on which the incident light ray is emitted,
In a lighting device comprising a light guide plate having a back surface facing the emission surface and a reflection plate (203) arranged so as to face the back surface of the light guide plate, the light guide plate is provided on the back surface of the light guide plate. It has a pit group consisting of a large number of pits each having a substantially triangular cross section and directed to the direction of the emission surface propagating in the optical plate, and the pit group is a pit row (254)
The lighting device is characterized in that a large number of pits are arranged and the pits are arranged in a staggered manner between adjacent pit rows. 6. A light source (201), an incident surface on which a light ray from the light source is incident, and an emission surface on which the incident light ray is emitted.
In a lighting device comprising a light guide plate having a back surface facing the emission surface and a reflection plate (203) arranged so as to face the back surface of the light guide plate, the light guide plate (261) is provided on the back surface. , A large number of grooves (26) directed toward the emission surface propagating in the light guide plate.
An illuminating device characterized in that 2) is arranged in a crossed arrangement. 7. A light source (201), an incident surface on which a light ray from the light source is incident, and an emission surface on which the incident light ray is emitted,
In a lighting device comprising a light guide plate having a back surface facing the emission surface and a reflection plate (203) arranged so as to face the back surface of the light guide plate, the light guide plate (271) is provided on the back surface. A plurality of substantially triangular grooves (272 to 277) that are directed in the direction of the emission surface propagating in the light guide plate are arranged to have a larger size as they approach the incidence surface and are arranged at equal pitches. Lighting device. 8. A light source (201), an incident surface on which a light ray from the light source is incident, and an emission surface on which the incident light ray is emitted.
In a lighting device including a light guide plate having a back surface facing the emission surface and a reflection plate (203) arranged so as to face the back surface of the light guide plate, the light guide plate (281) is provided on the back surface. , A pit group (282) composed of a large number of pits each having a substantially triangular cross section and directed in the direction of the emission surface propagating in the light guide plate, and the pit group is a pit row ( 284,
285) is arranged so as to intersect with each other. 9. A light source (201), an incident surface on which a light ray from the light source is incident, and an emission surface on which the incident light ray is emitted.
Grooves (318) facing the emitting surface and having a uniform pitch
A lighting device comprising: a light guide plate having a back surface having a light guide plate; and a reflection plate (203) arranged so as to face the back surface of the light guide plate, wherein the reflection plate (312) is provided on the upper surface of the light guide plate. Has a large number of ridges (313) for reflecting the light leaked from the back surface of the light guide plate and directing the light toward the light guide plate. An illumination device characterized in that a portion on the side opposite to the surface is arranged with a distribution having a narrower pitch (P11) than the central portion.