JP4040027B2 - Rear light source device - Google Patents

Description

  The present invention relates to a back light source device used for a liquid crystal display device.

  Conventionally, in a back light source device used for a liquid crystal display device, semiconductor light emitting elements are arranged in a line, and light emitted from these semiconductor light emitting elements is guided to a light guide plate diffusion plate by a light guide plate.

  For example, in the rear light source device disclosed in Patent Document 1 (Japanese Patent No. 2917866), the LED is fixed via a support. When the LED embedded in the support is used as a light source, a transparent material is selected for the support, and the end surface of the transparent support on which the LED is mounted and the end surface of the light guide plate are in close contact with each other, or an adhesive. The surface light source is completed by adhering via the surface.

Japanese Patent No. 2917866 (Column 7, lines 4-5, lines 12-14)

  In the conventional rear light source device described in Patent Document 1, since the number of semiconductor light emitting elements arranged facing the width of the side surface of the light guide plate is limited, the total amount of light that can be injected into the light guide plate is limited. There is. Therefore, there has been a problem in improving the luminance of the back light source device using the semiconductor light emitting element.

  In addition, when the semiconductor light emitting element is a point light source, brightness unevenness occurs, or when the three primary colors of red, green, and blue are mixed and used, the color unevenness is caused by the difference in the arrival amount of each primary color light. There was an inconvenience that occurred.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a back light source device having high brightness and no unevenness.

The present invention uses a semiconductor light emitting element as a light source, and in a back light source device that diffuses light emitted from the light source with a single light guide diffusion plate,
A plurality of rows of semiconductor light emitting devices;
Each said a plurality of rows plurality of light guide plates corresponding to each column of the semiconductor light emitting device, and a corresponding plurality of light guide plates only light emitted from the semiconductor light emitting element row leading to the light diffusing plate I have a,
In two adjacent columns of the plurality of columns of semiconductor light emitting elements, the light emitting elements in the second column are arranged between the adjacent light emitting elements in the first column.

  In the present invention, light emitted from a plurality of rows of semiconductor light emitting elements is made incident on one light guide diffusion plate by a light guide plate corresponding to each row, so that it has high brightness and uneven brightness. No back light source device can be realized.

Hereinafter, the present invention will be specifically described with reference to the drawings illustrating embodiments.
Embodiment 1 FIG.
FIG. 1 shows a side surface of a back light source device according to Embodiment 1 of the present invention. In the figure, the semiconductor light emitting elements in each of the semiconductor light emitting element arrays 1 and 3 are aligned in a direction perpendicular to the paper surface. Light emitted from the semiconductor light emitting element array 1 enters the light guide plate 2, and is further guided and diffused by the light guide diffusion plate 5. On the other hand, the light emitted from the semiconductor light emitting element array 3 is guided by the light guide plate 4 and further guided and diffused by the light guide diffusion plate 5. The light guided and diffused by the light guide diffusion plate 5 is emitted in a direction perpendicular to the surface of the light guide diffusion plate 5 (downward in the figure).

  With the above configuration, the light emitted from the two rows of semiconductor light emitting elements is mixed by the light guide diffusion plate 5, thereby increasing the amount of light and realizing a high-luminance back light source device. Further, in this configuration, two rows of semiconductor light emitting elements are used, but the same effect can be obtained even if two or more rows of semiconductor light emitting devices and correspondingly two or more light guide plates are used.

Embodiment 2. FIG.
FIG. 2 shows a back light source device according to Embodiment 2 of the present invention. In the second embodiment, the light guide plate 6 has a thinner structure than the light guide plate 2. In such a configuration, light emitted from the two semiconductor light emitting element rows 1 and 3 enters the light guide plate corresponding to each row, but the incident amount is large in the thick light guide plate 2 and incident in the thin light guide plate 6. The amount is reduced. For this reason, even if there is little light emission of the semiconductor light emitting element corresponding to the thick light guide plate 2, the incident light to the light guide diffusion plate 5 becomes uniform light, and a back light source device with little unevenness in brightness can be realized.

Embodiment 3 FIG.
FIG. 3 shows a back light source device according to Embodiment 3 of the present invention. In the third embodiment, the light guide plate 7 is longer than the light guide plate 2. With the above configuration, the light emitted from the two semiconductor light emitting element arrays enters the corresponding light guide plate. The longer light guide plate 7 has a longer optical path length, and the shorter light guide plate 2 has a shorter optical path length. If the optical path length is long, the light intensity becomes uniform but dark. By arranging the semiconductor light emitting element rows that emit bright light toward the longer light guide plate, the incident light to the light guide diffuser plate becomes uniform, and a back light source device with less unevenness in brightness can be realized.

Embodiment 4 FIG.
FIG. 4 shows a back light source device according to Embodiment 4 of the present invention. In Embodiment 4, the light guide plate 8 is longer and thicker than the light guide plate 2a. With such a configuration, light emitted from the two rows of semiconductor light emitting elements is incident on the light guide plate corresponding to each row. The longer and thicker light guide plate 8 has a longer optical path length but a larger amount of incident light, and the shorter and thinner light guide plate 2a has a shorter optical path length but a smaller amount of incident light. For this reason, the light incident on the light guide diffusion plate becomes uniform light on both sides, and a rear light source device with little unevenness in brightness can be realized.

Embodiment 5. FIG.
FIG. 5 shows a back light source device according to Embodiment 5 of the present invention. According to FIG. 5, the semiconductor light emitting element row 1 and the semiconductor light emitting element row 3 are adjacent to each other. In the fifth embodiment, in the semiconductor light emitting elements in the two adjacent columns, the semiconductor light emitting elements in the second column are arranged between the semiconductor light emitting elements adjacent in the first column. For example, the semiconductor light emitting element 9 in the semiconductor light emitting element row 1 is disposed between the adjacent semiconductor light emitting elements 11 and 12 in the semiconductor element row 3. Further, the semiconductor light emitting element 10 in the semiconductor light emitting element row 1 is arranged so as to be between the semiconductor light emitting elements 12 and 13 in the semiconductor light emitting element row 3.

  In the above configuration, when the light emitted from the semiconductor light emitting elements in the adjacent two rows 1 and 3 is input to the light guide diffusion plate 5 through the light guide plate corresponding to each row, the adjacent in one row Between the light rays emitted from the semiconductor light emitting elements to be operated, the light rays from the semiconductor light emitting elements in the other row are located. Therefore, a back light source device with little unevenness in brightness can be realized.

Embodiment 6 FIG.
FIG. 6 shows a back light source device according to Embodiment 6 of the present invention. In Embodiment 6, two rows of adjacent light emitting elements are provided, and the adjacent light emitting elements in row 1 emit light of the first primary color and light of the second primary color, respectively. The light emitting elements in the row 3 arranged between adjacent light emitting elements emit light of the third primary color. For example, in row 1, semiconductor light emitting elements of green 15, red 17, and blue 19 are arranged in order. In row 3, semiconductor light emitting elements of red 14, blue 16, and green 18 are arranged in order. For example, the green color 15 in the column 1 is arranged between the adjacent red color 14 and blue color 16 in the column 3. Further, the red color 17 in the column 1 is arranged between the adjacent blue color 16 and the green color 18 in the column 3. The plurality of different primary color lights are combined and arranged so as to be white as a whole.

  With the above configuration, each primary color light emitted from the two rows of semiconductor light emitting elements 1 and 3 is incident on the light guide plate corresponding to each column, and further incident on the light guide diffuser plate, so that the whole becomes white. A back light source with less color unevenness can be realized.

Embodiment 7 FIG.
FIG. 7 shows a back light source device according to Embodiment 7 of the present invention. The light guide plates 2 and 4 and the light guide diffusion plate 5 are arranged to overlap each other. A reflecting mirror 20 is provided so as to face the light output portions of the light guide plates 2 and 4 and the light input portion of the light guide diffusion plate 5.

  The light emitted from the column 1 of the semiconductor light emitting elements is transmitted through the light guide plate 2, reflected by the reflecting mirror 20, and enters the light guide diffusion plate 5. The light emitted from the column 3 of the semiconductor light emitting elements passes through the light guide plate 4, is reflected by the reflecting mirror 20, and enters the light guide diffusion plate 5. Since the light incident on the light guide diffusion plate 5 is uniformly diffused by the light guide diffusion plate 5, it is possible to realize a back light source device that is small and has no unevenness in brightness.

Embodiment 8 FIG.
FIG. 8 shows a back light source device according to Embodiment 8 of the present invention. In the eighth embodiment, the light guide diffusing plate 5 includes two light input portions 22 and 23, and the reflecting mirrors 21 and 20 facing the light input portions 22 and 23 are provided so as to sandwich the light guide diffusing plate 5. . The reflecting mirrors 20 and 21 have a cylindrical concave surface.

  The light emitted from the row 1A of semiconductor light emitting elements is reflected by the reflective film 28 having a curved surface, enters the light guide plate 24, passes through the light guide plate 24, is reflected by the reflecting mirror 20, and enters the light input unit 22. To do. The light emitted from the row 3A of semiconductor light emitting elements is reflected by the reflecting film 29 having a curved surface, enters the light guide plate 25, passes through the light guide plate 25, is reflected by the reflecting mirror 20, and enters the light input unit 22. To do.

  The light emitted from the row 1B of the semiconductor light emitting elements is reflected by the reflecting film 31 having a curved surface, enters the light guide plate 27, passes through the light guide plate 27, is reflected by the reflecting mirror 21, and enters the light input unit 23. To do. The light emitted from the row 3B of the semiconductor light emitting elements is reflected by the reflective film 30 having a curved surface, enters the light guide plate 26, passes through the light guide plate 26, is reflected by the reflecting mirror 21, and enters the light input unit 23. To do. The semiconductor light emitting element rows 1A, 1B, 3A, and 3B may be arranged so as to directly face the light input portions of the light guide plates 24, 25, 26, and 27, as shown in FIG. Since the light incident on the light guide diffusion plate 5 from the plurality of input portions is uniformly diffused, a small-sized back light source device with high brightness and no unevenness can be realized.

  Although Embodiments 1 to 8 have been described above, it is also possible to configure a back light source device by further combining these embodiments.

It is a side view which shows Embodiment 1 of this invention. It is a side view which shows Embodiment 2 of this invention. It is a side view which shows Embodiment 3 of this invention. It is a side view which shows Embodiment 4 of this invention. It is a layout view showing a fifth embodiment of the present invention. It is a layout view showing a sixth embodiment of the present invention. It is a side view which shows Embodiment 7 of this invention. It is a perspective view which shows Embodiment 8 of this invention.

Explanation of symbols

1, 3 Semiconductor light emitting element row, 2, 4, 6, 7, 8 Light guide plate, 5 Light guide diffuser plate, 9, 10, 11, 12, 13, 14 Conductor light emitting element, 15, 16, 17, 18, 19 Semiconductor light emitting element, 20, 21 reflector, 22, 23 Light input part.

Claims (3)

In a back light source device that uses a semiconductor light emitting element as a light source and diffuses light emitted from the light source with a single light guide diffusion plate,
A plurality of rows of semiconductor light emitting devices;
Each said a plurality of rows plurality of light guide plates corresponding to each column of the semiconductor light emitting device, and a corresponding plurality of light guide plates only light emitted from the semiconductor light emitting element row leading to the light diffusing plate Have
2. A back light source device according to claim 1, wherein in two adjacent rows of the plurality of rows of semiconductor light emitting devices, the light emitting devices in the second row are arranged between the light emitting devices adjacent in the first row.   The adjacent light emitting elements in the first row emit light of the first primary color and the light of the second primary color, respectively, and the second light emitting elements arranged between the adjacent light emitting elements in the first row. 2. The back light source device according to claim 1, wherein the light emitting elements in the row emit light of a third primary color. The first row includes a first light emitting element that emits light of a first primary color, a second light emitting element that emits light of a second primary color, and a third light that emits light of a third primary color. A plurality of element rows arranged in this order in series are connected in series, and of the two adjacent element rows, the first light-emitting element in the subsequent element row is the first element row in the previous element row. 3 adjacent to the light emitting element 3
The second row includes a first light emitting element that emits light of a first primary color, a second light emitting element that emits light of a second primary color, and a third light that emits light of a third primary color. A plurality of element rows arranged in this order in series are connected in series, and of the two adjacent element rows, the first light-emitting element in the subsequent element row is the first element row in the previous element row. 3 adjacent to the light emitting element 3
The light emitting elements in the second column located between two adjacent light emitting elements in the first column are different from the light emitted by the two adjacent light emitting elements in the first column. The rear light source device according to claim 1, wherein the rear light source device emits the light of.

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