JPH09230144A - Back light and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently arrange light sources in a limited space and to provide a small-sized and high luminance back light by oppositely providing plural light sources with different outside diameters on a side surface of a light transmission plate. SOLUTION: The light outgoing from the light-emitting surface 9 of the light transmission plate 2 is diffused by a diffusion sheet 7 after is direction is corrected by a prism sheet 6. In such a manner, when the light outgoing from a back light 101 in planar state is projected on a liquid crystal panel from a rear, its image is satisfactorily seen three-dimentionally. Then, since plural light sources 102, 103 are confronted with one light incident part 8 of the light transmission plate 2, a large quantity of light is made incident on the light incident part 8 of the light transmission plate 2, and the luminance of the light-emitting surface 9 of the light transmission plate 2 becomes excellent. Particularly, since a piece of small-sized light source 103 is confronted with a gap 104 between two pieces of large-sized light sources 102, the light is made incident on the light incident part 8 of the light transmission plate 2 from the gap 104 between the large-sized light sources 102, and the light of the light sources 102, 103 is effectively used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight and a liquid crystal display.

[0002]

2. Description of the Related Art Liquid crystal display devices are used for displays of portable computers, and such liquid crystal display devices are equipped with a backlight. There are various types of such backlights, and one of them is a backlight called a light guide plate type.

A conventional example of such a backlight is shown in FIG.
This will be described with reference to FIG. FIG. 15 is a sectional view of the backlight. In the figure, a backlight 1 includes a rectangular flat light guide plate 2, two tubular light sources 3, a pair of reflecting mirrors 4, a reflecting plate 5, a prism sheet 6 as a first light diffusing plate, and a second light diffusing plate. A diffusion sheet 7, which is a light diffusion plate, is provided.

The light guide plate 2 is a rectangular flat plate that transmits light rays, and the left and right side faces in the drawing are formed as a light entrance portion 8, the upper surface in the drawing is formed as a light emitting surface 9, and the lower back surface in the drawing is formed as a reflecting surface 10. Has been done. The light sources 3 are, for example, hot-cathode fluorescent tubes, and are individually arranged so as to face the light entrance portions 8 on both sides of the light guide plate 2. The reflecting mirror 4 is formed of, for example, a metal plate curved in a semicircular shape, and the light guide plate 2 is provided so as to individually surround the light sources 3.
It is mounted on both sides of the. The reflection plate 5 is formed of, for example, a rectangular flat metal sheet, and is attached to the reflection surface 10 of the light guide plate 2. The prism sheet 6 is a transparent sheet body having a large number of fine prisms formed on its surface, and is attached to the light exit surface 9 of the light guide plate 2. The diffusion sheet 7 is a rectangular flat plate that diffuses the light rays that are transmitted,
It is arranged on the surface of the prism sheet 6.

The above-mentioned backlight 1 is used, for example, as a part of a liquid crystal panel and a liquid crystal display device. In that case, when the two light sources 3 are turned on, the light rays are reflected by the pair of reflecting mirrors 4 and enter the light incident portion 8 of the light guide plate 2. Thus, the light rays incident on the light incident portion 8 are guided through the inside of the light guide plate 2, are reflected by the reflection plate 5 of the reflection surface 10, and are emitted from the light emission surface 9. Thus, the light guide plate 2
The direction of the light beam emitted from the light exit surface 9 is corrected by the prism sheet 6 and diffused by the diffusion sheet 7.

[0006]

The above-described backlight 1 can emit the light beams emitted from the two light sources 3 in a planar manner from the surface of the light guide plate 2.

However, when the large-sized backlight 1 having the above-mentioned structure is produced, the light amount of the two light sources 3 may be insufficient. In that case, since the brightness of the backlight 1 is not sufficient, the visibility of the liquid crystal display device using the backlight 1 is deteriorated.

Therefore, it is an object of the present invention to provide a high brightness backlight and a liquid crystal display device using this backlight.

[0009]

A backlight according to a first aspect of the present invention comprises a light guide plate having a side surface, a back surface and a light emitting surface;
At least a light source group including a plurality of light sources arranged on the side surface side of the light guide plate and having different outer diameters; and a reflection plate arranged on the back surface of the light guide plate are provided. Therefore, when a plurality of light sources are turned on, the light rays are incident on the side surface of the light guide plate and are emitted from the light emitting surface by being reflected by the reflecting plate on the back surface thereof, so that a large amount of light rays are emitted to the side surface of the light guide plate. The brightness of the light emitting surface can be improved by making the light incident. Furthermore, since the outer diameters of the plurality of light sources are different, the plurality of light sources can be arranged in a limited space with high efficiency, and the light sources can be arranged in positions that would otherwise be dead spaces.

The backlight of the invention of claim 2 is a side surface,
A light guide plate having a back surface and a light emitting surface; at least two first light sources provided on the side surface side of the light guide plate and having substantially the same outer diameter, and an outer diameter provided between the first light sources. A light source group including a second light source having a small diameter; a reflecting mirror arranged so as to surround the light source group; and a reflecting plate arranged on the back surface of the light guide plate. Therefore, when a plurality of light sources are turned on, the light rays are reflected by a reflecting mirror and are incident on the side surface of the light guide plate, and are reflected by the reflecting plate on the back surface thereof and are emitted from the light emitting surface. A large amount of light rays can be incident on the side surface of the light guide plate to improve the brightness of the light exit surface.
Furthermore, since the second light source with a small diameter is located between the two first light sources, a plurality of light sources are arranged in a limited space with high efficiency, and the light source is arranged in a position that would otherwise be a dead space. It

The backlight of the invention of claim 3 is a side surface,
A light guide plate having a back surface and a light emitting surface; a light source group composed of a plurality of light sources arranged at least on a side surface side of the light guide plate and having different outer diameters; and a reflector arranged so as to surround the light source group. And; at least one light diffusing plate disposed on the exit surface side of the light guide plate; and a reflecting plate disposed on the back surface of the light guide plate. Therefore, when a plurality of light sources are turned on, the light rays are incident on the side surface of the light guide plate, reflected by the reflecting plate on the back surface thereof, emitted from the light emitting surface, and diffused by the light diffusing plate. A light beam can be incident on the side surface of the light guide plate to improve the brightness of the light exit surface. Furthermore, since the outer diameters of the plurality of light sources are different, the plurality of light sources can be arranged in a limited space with high efficiency, and the light sources can be arranged in positions that would otherwise be dead spaces.

The backlight of the invention of claim 4 is a side surface,
A light guide plate having a back surface and a light emitting surface; a light source group composed of a plurality of light sources arranged at least on a side surface side of the light guide plate and having different outer diameters; and a reflector arranged so as to surround the light source group. And; at least one light diffusing plate disposed on the emission surface side of the light guide plate; a reflecting plate disposed on the back surface of the light guiding plate; accommodating the light guiding plate, the light source, the reflecting mirror, the reflecting plate and the light diffusing plate And a case body that Therefore, when a plurality of light sources are turned on, the light rays are incident on the side surface of the light guide plate, reflected by the reflecting plate on the back surface thereof, emitted from the light emitting surface, and diffused by the light diffusing plate. A light beam can be incident on the side surface of the light guide plate to improve the brightness of the light exit surface. Furthermore, since the outer diameters of the plurality of light sources are different, the plurality of light sources can be arranged in a limited space with high efficiency, and the light sources can be arranged in positions that would otherwise be dead spaces.

According to a fifth aspect of the present invention, there is provided the backlight according to the first or fourth aspect, further comprising a support mechanism for supporting the light diffusing plate in a state permitting expansion and contraction thereof. Therefore, the light diffusion plate supported by the support mechanism diffuses the light emitted from the light guide plate, and the support mechanism allows the light diffusion plate to expand and contract due to temperature change or the like.

According to a sixth aspect of the present invention, in the backlight according to the fifth aspect, further, the light diffusing plate is formed in a rectangular shape, and the supporting mechanism supports the light diffusing plate at two adjacent side portions. To do. Therefore, the light diffusing plate is supported by the supporting mechanism at the two side portions where the light diffusing plate is erected, and the light diffusing plate can freely expand and contract in the directions of the two sides which are not supported.

A liquid crystal display device according to a seventh aspect of the present invention includes the backlight according to any one of the first to sixth aspects, and a liquid crystal panel disposed on a light emitting surface of the backlight. Therefore, the brightness of the backlight is improved and the contrast of the image displayed on the liquid crystal panel is improved.

In each of the above inventions, the light exit surface of the light guide plate is one surface through which the light beam incident on the side surface is emitted, and it is not necessary to have a specific structure, and the surface of the light guide plate formed as a rectangular flat plate is allowed. To do. The light source may be a tube that emits light, and allows a cold cathode fluorescent tube or a hot cathode fluorescent tube. However, since the cold cathode fluorescent tube can be easily reduced in diameter, it is more suitable for the present invention than the hot cathode fluorescent tube.

[0017]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a sectional view of the backlight. In the first embodiment, the same parts as those of the above-described conventional example use the same names and are given the same reference numerals. In the figure, the backlight 101 is
The light guide plate 2, the large-diameter tubular light source 102, the small-diameter tubular light source 103, the reflecting mirror 4, the reflecting plate 5, the prism sheet 6, and the diffusion sheet 7 are provided.

That is, the backlight 10 of the present embodiment.
1 is a backlight 1 described above as one conventional example,
Only the structures of the light sources 102 and 103 are different,
A plurality of light sources 102 and 103 having different outer diameters are arranged at positions facing both of the light entrance portions 8 on both side surfaces of the light guide plate 2. The light sources 102 and 103 are, for example, cold-cathode fluorescent lamps, and two large-diameter light sources 102 are arranged in parallel with each other in the light incident portion 8 of the light guide plate 2 in parallel. The small-diameter light source 103 is arranged so as to face the gap 104 between the two large-diameter light sources 102, and faces the light incident portion 8 of the light guide plate 2 via the gap 104.

The operation of the above embodiment will be described. The above-mentioned backlight 101 is arranged on the back side of the liquid crystal panel as a part of the liquid crystal display device, for example. When the two light sources 102 and 103 are turned on, the light rays are reflected by the reflecting mirror 4 and enter the light incident portion 8 of the light guide plate 2. Thus, the light rays incident on the light incident portion 8 are guided through the inside of the light guide plate 2, are reflected by the reflection plate 5 of the reflection surface 10, and are emitted from the light emission surface 9. The light rays emitted from the light exit surface 9 of the light guide plate 2 are diffused by the diffusion sheet 7 after the direction of the light rays is corrected by the prism sheet 6.
In this way, by projecting the light rays emitted from the backlight 101 in a plane shape onto the liquid crystal panel from the back side, the image can be well highlighted.

Then, the backlight 10 according to the present embodiment.
1 is a plurality of light sources 102 in one light entrance portion 8 of the light guide plate 2,
Since 103 are opposed to each other, a large amount of light rays can be incident on the light incident portion 8 of the light guide plate 2, and the light exit surface 9 of the light guide plate 2 can be incident.
The brightness is good. In particular, since one small-diameter light source 103 is opposed to the gap 104 between the two large-diameter light sources 102, the light beam emitted from the small-diameter light source 103 is the large-diameter light source 1.
The light rays from the plurality of light sources 102 and 103 are effectively used because they are incident on the light incident portion 8 of the light guide plate 2 through the gap 104 of 02.

Further, as described above, the two large-diameter light sources 102 are provided.
Since one small-diameter light source 103 is opposed to the gap 104, the large-diameter light source 102 and the small-diameter light source 103 are highly efficiently arranged in a limited space, and should be located at a position that would otherwise be a dead space. A light source 103 having a small diameter is arranged. Therefore, the brightness of the backlight 101 is improved without increasing the space occupied by the light sources 102 and 103, and the entire size of the backlight 101 can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 2 is a sectional view of the backlight. In addition, in this 2nd Embodiment, the same part as 1st Embodiment mentioned above uses the same name, and attaches the same code | symbol. In the figure, in the backlight 201, one large-diameter light source 3 and two small-diameter light sources 103 are arranged to face each of the light entrance portions 203 on both sides of the light guide plate 202. The light entrance portion 203 of the light guide plate 202 is formed so that its cross-sectional shape is a triangle protruding outward, and slopes 204, 2 which are side surfaces inclined upward and downward.
05 is formed.

The two small-diameter light sources 103 are arranged in parallel, and the two inclined surfaces 20 of the light entrance portion 203 of the light guide plate 202.
4, 205 are individually opposed. One large-diameter light source 3
Are arranged so as to face the gap 206 between the two small-diameter light sources 103, and face the light incident portion 203 of the light guide plate 202 via the gap 206.

The operation of the above embodiment will be described. The backlight 201 according to the present embodiment includes the light guide plate 20.
Since a plurality of light sources 3 and 103 are opposed to one light incident portion 203 of No. 2, a large amount of light rays are incident on the light incident portion 2 of the light guide plate 202.
03, and the light exit surface 9 of the light guide plate 202.
The brightness is good. In particular, since one large-diameter light source 3 is opposed to the gap between the two small-diameter light sources 103, the light beam emitted by the large-diameter light source 3 is separated by the gap 20 between the small-diameter light sources 103.
The light beams from the plurality of light sources 3 and 103 are effectively used because they are incident on the light incident portion 203 of the light guide plate 202 from the light source 6. Further, since the light incident portion 203 of the light guide plate 202 is formed with the two inclined surfaces 204 and 205, the surface area of the light incident portion 203 is increased and a large amount of light rays can be incident. , 205 each having a small diameter light source 10
Since the light sources 3 face each other, the light rays can be incident on the light incident portion 203 with high efficiency.

Further, as described above, the two small-diameter light sources 10 are used.
Since one large-diameter light source 3 is opposed to the gap 206 of three, the small-diameter and large-diameter light sources 3 and 103 are arranged in a limited space with high efficiency, and are originally dead spaces. A light source 103 having a small diameter is arranged at the position. Therefore, the brightness of the backlight 201 is improved without increasing the space occupied by the light sources 3 and 103, and the backlight 201 can be downsized as a whole.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 3 is a sectional view of the backlight. In the third embodiment, the same parts as those in the above-mentioned conventional example use the same names and are given the same reference numerals. In the figure, a backlight 301
In addition to a single large-diameter light source 3 being arranged to face each of the light entrance portions 8 on both sides of the light guide plate 302, the light guide plate 302 also has a triangular cross-section that is recessed inward on the back side of the light guide plate 302. Light section 30
3 is formed by two slopes 304 and 305,
One small-diameter light source 103 is arranged opposite to the light incident portion 303.

The operation of the above embodiment will be described. The backlight 301 according to the present embodiment includes the light guide plate 30.
A plurality of light sources 3, 1 are provided in each of the three light entrance portions 8, 303 of 2.
Since 03 are individually faced, a large amount of light rays can be incident on the light guide plate 302, and the brightness of the light exit surface 9 of the light guide plate 302 is good. In particular, the light entrance part 3 of the light guide plate 302
Since 03 has two slopes, a large amount of light rays can be incident, and the light rays can be incident on the light incident portion 303 with high efficiency. Further, since the light incident portion 303 is formed on the back side of the light guide plate 302 to secure a small space and the small diameter light source 103 is arranged therein, the small diameter light source 103 is arranged in a position that would normally be a dead space. Therefore, the brightness is improved without increasing the size of the backlight 301.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 4 is a sectional view of the backlight. In the fourth embodiment, the same parts as those in the second embodiment described above use the same names and are given the same reference numerals. In the figure, in the backlight 401, one large-diameter light source 3 and two small-diameter light sources 103 are arranged to face each of the light entrance portions 203 on both sides of the light guide plate 402. Light-receiving part 4 on the back side of
One small-diameter light source 103 is also arranged at 03. A curved surface 404 that is curved like a dome is formed on the light incident portion 403.

The operation of the above-described embodiment will be described. The backlight 401 of the present embodiment is the light guide plate 40.
A plurality of light sources 3, 103 are provided on each of the light entrance portions 203 on both sides of
And a small-diameter light source 103 is also made to face the light incident portion 403 on the back side, so that an extremely large amount of light rays can be incident on the light guide plate 402, and the brightness of the light exit surface 9 of the light guide plate 402 is good. Is.

As described above, the light source 1 is provided on the back side of the light guide plate 402.
When 03 is arranged, the light ray reaches the light emitting surface 9 in a short distance, so there is a concern that only the center of the light emitting surface 9 becomes bright. However, in the above-described backlight 401, a smooth curved surface 404 is formed on the light incident portion 403 on the back side of the light guide plate 402, and a large number of large and small light sources 3, 3 are formed on each of the light incident portions 203 on both sides of the light guide plate 402. Since 103 are opposed to each other, the entire area of the light emitting surface 9 can be made to emit light uniformly.

A fifth embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. 5 is a perspective view of the backlight, and FIG. 6 is an exploded perspective view of the backlight. In the fifth embodiment, the same parts as those in the first embodiment described above use the same names and are given the same reference numerals. In the backlight 501 of the present embodiment, one light unit 502 is formed by the light guide plate 2, the large and small light sources 102 and 103, the pair of reflecting mirrors 4, the reflecting plate 5, and the prism sheet 6. The light unit 502 is housed in the internal space of the support mechanism 503 which is also the case body, and the light diffusion plate 504 is supported by the support mechanism 503 in a state in which it can be expanded and contracted.

More specifically, the support mechanism 503 is formed in the shape of a box having an open top surface, and one projecting piece 506 is projectingly provided at the upper edge of each of the four side portions 505. However, these protrusions 506 have four sides 5
The support mechanism 50 is not located in the center of each of the
It is displaced clockwise when viewed from the center of 3. Since the support mechanism 503 is formed by such a structure, the four protrusions 506 supporting the light diffusion plate 504 do not face each other in parallel, but support the light diffusion plate 504 in a swastika shape.

The backlight 5 having the above-mentioned structure
01 means that the light diffusing plate 504 cannot be prevented from coming off as it is. However, since the backlight 501 is arranged inside the liquid crystal display device as its name implies,
A liquid crystal panel or the like is arranged at a position that shields the light diffusion plate 504. In such a state, the light diffusion plate 50 is
4 will not drop out.

The operation of the above embodiment will be described. In the backlight 501 described above, like the backlight 101 described above, since the plurality of light sources 102 and 103 are opposed to one light entrance portion 8 of the light guide plate 2, the light unit 502 has high brightness.

Then, the backlight 50 of the present embodiment.
1 is supported by the four protrusions 506 of the support mechanism 503 in a state where the light diffusion plate 504 allows expansion and contraction.
Even if the light diffusing plate 504 expands or contracts due to a temperature change or the like, excessive stress does not act on the light diffusing plate 504, and the deformation and damage of the light diffusing plate 504 can be prevented.

The present invention is not limited to the above-described embodiment, but allows various modifications. For example, although it has been described here that the light diffusing plate 504 is prevented from falling off by the liquid crystal panel or the like, when the liquid crystal panel or the like is not located at such a position, as shown in FIG.
It is preferable that the projecting piece 513 of the support mechanism 512, which is also the case main body, be extended and bent to hold the light diffusion plate 504.

In addition, the backlight 501, as described above,
In 511, even if it is erected, the light diffusion plate 504 is surely supported from above, below, left, and right. However, when the direction in which the light diffusion plate 504 is to be erected is known, the protrusion 50 located above it is shown.
It is possible to omit 6,513. Further, FIG.
As shown in FIG. 7, in the case of the backlight 521 whose standing direction is known, it is possible to position the projecting pieces 523 of the support mechanism 522, which is also the case main body, at the upper part and the lower part.

FIG. 9 and FIG. 1 show the sixth embodiment of the present invention.
0 will be described. FIG. 9 is a perspective view of the backlight, and FIG. 10 is an enlarged perspective view of a main part. In the sixth embodiment, the same parts as those in the fifth embodiment described above use the same names and are given the same reference numerals. In the backlight 601 of the present embodiment, projecting pieces 603 are formed at a pair of diagonal corners of the support mechanism 602 which is also the case body, and the light diffusing plate 604 allows expansion and contraction by these projecting pieces 603. Supported by the state. More specifically, the projecting piece 603 is a support 605.
The light diffusing plate 6 has a concave portion 607 with which the convex portion 606 is engaged.
It is formed at the corner of 04.

The operation of the above-described embodiment will be described. The above-described backlight 601 is similar to the above-described backlight 501 in that the support mechanism 602 allows the light diffuser plate 604 to operate.
Is supported in a state in which it can be expanded and contracted, so that its deformation and damage can be prevented. The support mechanism 602
When the light diffusing plate 604 is supported by, the projecting piece 603 is first attached to the side portion 505 of the supporting mechanism 602 as shown in FIG.
It is only necessary to position the light diffusing plate 604 in parallel with, and then rotate the protrusion 603 inward.

It is sufficient that the projecting pieces 603 are provided at a pair of diagonally opposite corners of the supporting mechanism 602 as described above, but as shown in FIG. 11, the standing direction of the backlight 611 is known. In that case, it is preferable to provide the protrusions 603 at both corners of the support mechanism 612 that is also the case body in the lower part.

A seventh embodiment of the present invention will be described with reference to FIG. FIG. 12 is a perspective view of the backlight.
In addition, in this 7th Embodiment, the same part as 5th Embodiment mentioned above uses the same name, and attaches the same code | symbol. Backlight 7 of the present embodiment
In 01, the two adjacent side portions 703 of the support mechanism 702 which is also the case main body are protruded from the other adjacent two side portions 505, and the light diffusion plate 504 is attached to the inner surface of these side portions 703 by the adhesive. Since it is mounted by 704, the light diffusion plate 504 is supported by the adjacent two sides.

The operation of the above-described embodiment will be described. In the above-described backlight 701, since the light diffusion plate 504 is supported by the adjacent two sides by the support mechanism 702, the light diffusion plate 504 can freely expand and contract in the directions of the two sides not supported. It is possible to prevent deformation and damage due to this expansion and contraction.

The backlight 501 as described above can handle all the standing directions, but has two side portions 703.
It is preferable to position one of the two below. However, when the side portion 703 cannot be arranged below due to various reasons, it is preferable to add the projecting piece 603 below the support mechanism 712 which is also the case main body of the backlight 711, as shown in FIG.

An eighth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a perspective view of the liquid crystal display device.
The liquid crystal display device 801 according to the present embodiment includes the backlight 1
01, a liquid crystal panel 802, and a main body housing 803. The backlight 101 is joined to the back surface of the liquid crystal panel 802, and the surface of the liquid crystal panel 802 is located in the opening hole 804 of the main body housing 803.

The operation of the above-described embodiment will be described. In the above-described liquid crystal display device 801, since the built-in backlight 101 is small and the brightness is high, the image on the liquid crystal panel 802 can be well highlighted, and the entire size is small.

[0046]

According to the invention of claims 1 to 4, a plurality of light sources having different outer diameters face the side surface of the light guide plate, so that the plurality of light sources can be arranged in a limited space with high efficiency. Since it is possible to arrange the light source in a position that would otherwise be a dead space, it is possible to provide a small-sized backlight with high brightness.

According to the fifth and sixth aspects of the present invention, since the light diffusing plate is supported by the supporting mechanism in a state in which the light diffusing plate is allowed to expand and contract, even if the light diffusing plate expands and contracts due to temperature changes, etc. It is possible to prevent the light diffusion plate from being deformed or damaged without causing any stress.

According to the invention of claim 7, since the liquid crystal panel is arranged so as to face the light emitting surface of the backlight according to any one of claims 1 to 7, the liquid crystal display is compact and has good image visibility. A device can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a backlight according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a backlight according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a backlight according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a backlight according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view of a backlight according to a fifth embodiment of the present invention.

FIG. 6 is an exploded perspective view of the same.

FIG. 7 is a perspective view of a first modification of the fifth embodiment.

FIG. 8 is a perspective view of a second modification of the fifth embodiment.

FIG. 9 is a perspective view of a backlight according to a sixth embodiment of the present invention.

FIG. 10 is a perspective view of an enlarged main part of the same.

FIG. 11 is a perspective view of a modification of the sixth embodiment.

FIG. 12 is a perspective view of a backlight according to a seventh embodiment of the present invention.

FIG. 13 is a perspective view of a modification of the seventh embodiment.

FIG. 14 is a sectional view of a liquid crystal display device according to an eighth embodiment of the present invention.

FIG. 15 is a sectional view of a conventional backlight.

[Explanation of symbols]

 2: Light guide plate 3: Light source 4: Reflector 5: Reflector plate 6: Light diffuser plate 7: Light diffuser plate 8: Side surface 9: Light emitting surface 101: Backlight 102, 103: Light source 104: Gap 201: Backlight 202: Light guide plate 203: Side surface 206: Gap 301: Back light 302: Light guide plate 303: Side surface 401: Back light 402: Light guide plate 403: Side surface 501: Back light 503: Case body, support mechanism 504: Light diffusion plate 511: Back light 512: Case Main Body, Support Mechanism 521: Backlight 522: Case Main Body, Support Mechanism 601: Backlight 602: Case Main Body, Support Mechanism 604: Light Diffusing Plate 611: Backlight 612: Case Main Body, Support Mechanism 701: Backlight 702 : Case body, support mechanism 711: Backlight 712: Case body, Lifting mechanism 801: liquid crystal display device 802: a liquid crystal panel

Claims (7)

[Claims] 1. A light guide plate having a side surface, a back surface, and a light exit surface; a light source group including at least a plurality of light sources having different outer diameters arranged on the side surface side of the light guide plate; and arranged on the back surface of the light guide plate. A backlight comprising: a reflection plate provided; 2. A light guide plate having a side surface, a back surface, and a light emitting surface; two first light sources arranged at least on the side surface side of the light guide plate and having substantially the same outer diameter, and a first light source of these first light sources. A light source group configured by: a second light source having an outer diameter and a small diameter, which is disposed between;
A backlight comprising: a reflecting mirror arranged so as to surround a light source group; and a reflecting plate arranged on the back surface of the light guide plate. 3. A light guide plate having a side surface, a back surface, and a light exit surface; a light source group composed of a plurality of light sources arranged on at least a side surface of the light guide plate and having different outer diameters; A reflecting mirror disposed on the light guide plate, and at least one light diffusing plate disposed on the exit surface side of the light guide plate; and a reflecting plate disposed on the back surface of the light guide plate. Back light. 4. A light guide plate having a side surface, a back surface, and a light exit surface; a light source group including at least a plurality of light sources having different outer diameters arranged on the side surface side of the light guide plate; and surrounding the light source group. A reflecting mirror disposed on the light guide plate, at least one light diffusing plate disposed on the exit surface side of the light guide plate, a reflecting plate disposed on the back surface of the light guide plate, a light guide plate, a light source, a reflecting mirror, and reflection A case main body for accommodating a plate and a light diffusing plate; 5. The backlight according to claim 1, further comprising a support mechanism that supports the light diffusion plate in a state where the light diffusion plate is allowed to expand and contract. 6. The backlight according to claim 5, wherein the light diffusing plate is formed in a rectangular shape, and the support mechanism supports the light diffusing plate at two adjacent sides. 7. A liquid crystal display device comprising: the backlight according to claim 1; and a liquid crystal panel arranged on a light emitting surface of the backlight.