JPH0981050A - Structure for mounting light transmission plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to embody a back light having the nearly uniform luminance of a light transmission plate without the need for worrying about the deviation in a light source by the variation in packaging and to reduce a fabrication cost as there is no need for post stages, such as soldering. SOLUTION: This structure is used for mounting the light transmission plates of products having light sources, circuit boards and light transmission plates. A chip LED is used as, for example, the light source of the light transmission plate. This light source 2 is previously fitted into a recessed part 3 previously disposed in part of the light transmission plate 1. The recessed part 3 is previously provided with projections 4 at three points or four points in order to prevent the misalignment of the optical axis of the light source 2. The chip part of the light source 2 is mounted while the projections 4 are made to collapse, by which the prevention of shaking is made possible. Anisotropic conductors 7 and conductive paste, etc., are previously attached to the patterns of the circuit board 5 in order to electrically obtain the continuity with the light source 2, by which the electrical conduction is assured as well simultaneously fixing by thermal caulking, claws for fixing, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate mounting structure for a product having a light source, a circuit board and a light guide plate.

[0002]

2. Description of the Related Art In the conventional structure, as shown in FIG. 3, before the light guide plate 1 is fixed to the circuit board 5, a light emitting body to be a light source 2 is mounted on the circuit board 5 by soldering 8 for electrical conduction. Or a light guide plate 1 on which a light source 2 is mounted in advance
Since the terminal of the light source 2 or the sub-board is soldered to the circuit board 5 after fixing the position of the circuit board 5 to the circuit board 5,
When the light source 2 is mounted on the circuit board 5, the optical axis of the light source 2 is deviated from the expected direction, the brightness of the light guide plate 1 is not uniform, and the assembly process is complicated, which takes time.

[0003]

As described above, according to the prior art, when the light source is mounted on the circuit board, the optical axis of the light source may be displaced from the expected direction due to mounting unevenness, and the lighting area may be increased. However, when a plurality of light sources are used, the optical axes of the light sources may not be parallel, and the brightness of the light guide plate may not be uniform, resulting in a low-quality backlight. In addition, when fixing the light source to the light guide plate in advance and fixing the position with the circuit board, to obtain electrical continuity by soldering,
Although the optical axis of the light source does not shift, separate work for soldering is required and the processing cost increases. Therefore, the present invention can prevent the optical axis of the light source from being distorted by a simple operation.

[0004]

According to the present invention, a concave portion for fitting a light source is provided in a part of a light guide plate, and a chip component to be a light source is previously fitted in this part, and the light guide plate is mounted on a circuit board. When positioning and fixing, the fixing means secures electrical continuity between the light source and the circuit board, so that the optical axis of the light source is directed in the direction as expected of the design without distortion. If the light source is a chip LED, it can be mounted sideways to emit light. As a method of positioning and fixing the light guide plate in the present invention, when the dowel is formed in the light guide plate and the dowel is inserted into the hole of the circuit board and the position is fixed, it is easy to fix by heat caulking. Further, in the present invention, in order to ensure electrical continuity between the circuit board and the light source, an anisotropic conductor may be sandwiched between the circuit board and the light source.

[0005]

FIG. 1 is a sectional view of a product showing an embodiment of the present invention. Now, the structure of the light guide plate of the present invention will be briefly described. In the light guide plate 1 of the present invention, first, the required number of light sources 2 is calculated from the lighting area of the product, and in order to make the brightness of the light guide plate 1 as uniform as possible, the light source 2 is placed at a position where the light intensity is not deviated from the light distribution as much as possible. To place. When the place to arrange is determined, the recess 3 is formed in the light guide plate 1 in order to fit the chip component of the light source 2. In order to prevent the optical axis from being displaced due to backlash after the light source 2 is fitted into the recessed portion 3, three or four protrusions 4 are formed so as to have a slightly small width dimension in order to previously sandwich the chip component to be the light source 2 from the side. When the chip component of the light source 2 is fitted, the projection 4 can be mounted while being slightly crushed to prevent backlash after the fitting. In this way, the light guide plate 1 incorporating the light source 2 is fixed to the circuit board 5 by thermal caulking or fixing claws. The light source 2 is previously formed on the pattern of the circuit board 5.
In order to establish electrical continuity with the anisotropic conductor 7, an anisotropic conductor 7 or a conductive paste is attached, and the electrical continuity is secured at the same time as being fixed by thermal caulking or fixing tabs. This way,
The position of the light source 2 does not shift due to variations in mounting, and a post process such as soldering is unnecessary.

FIG. 2 is a plan view of a product showing an embodiment of the present invention, but is drawn with a broken line so that the positional relationship of the light source 2 can be clearly understood. In this case, two light sources 2 are arranged on each of the left and right, but the size of the LCD 6 is about 30 mm.
When the chip LED is used for the light source 2 in the case of x40 mm or more, it is considered that at least two chips are necessary because the light intensity of the LED is limited when trying to illuminate the entire LCD brightly. Further, depending on the electrode position of the LCD 6, there may be left and right arrangement and top and bottom arrangement. In any case,
The optical axis of the light source 2 does not shift due to mounting variations.

[0007]

As described above, according to the present invention, a chip component or the like serving as a light source is previously incorporated in a predetermined position of the light guide plate, and the light source and the circuit board are fixed by means of fixing the light guide plate to the circuit board. Since electrical continuity is also secured, there is no need to worry about deviation of the light source due to variations in mounting, and it is possible to realize a backlight in which the brightness of the light guide plate is nearly uniform. Also, the post-process such as soldering is unnecessary and the processing cost can be kept low. For example, if claw fixing is used as a fixing method other than thermal caulking, reworkability is dramatically improved and a backlight with good usability is obtained. Become. In this example, a chip LED is assumed, but in the present invention, since the light source is incorporated in a part of the light guide plate, it is sufficient that the light guide plate of the lighting portion is slightly thicker than the chip LED, and the thickness is about 1 mm. Since it can be realized, it can be expected to have a considerable effect even in fields such as mobile communication devices where downsizing and thinning are key points.

Further, in the present invention, only the chip LED and the like used as the light source of the light guide plate are described, but in general, general electronic parts can be mounted by the same method, and when the number of parts is small, It is also possible to make a module with a backlight without soldering.

[Brief description of drawings]

FIG. 1 is a sectional view of a product showing an embodiment of the present invention.

FIG. 2 is a plan view of a product showing an embodiment of the present invention.

FIG. 3 is a diagram showing an attachment structure of a light guide plate in a conventional product.

[Explanation of symbols]

 1 ... Light guide plate 2 ... Light source 3 ... Recessed portion 4 ... Protrusion 5 ... Circuit board 6 ... LCD 7 ... Anisotropic conductor 8 ... Solder

Claims (4)

[Claims] 1. When mounting a light guide plate of a backlight, which uses a chip component as a light source, on a circuit board, the chip component serving as the light source is fitted into a recess provided in the light guide plate in advance to separate the circuit board and the light guide plate. A mounting structure for a light guide plate, wherein a fixing means for positioning and fixing also serves as a pressing force for ensuring electrical continuity between the circuit board and the light source. 2. The light guide plate mounting structure according to claim 1, wherein the chip component used as the light source is a chip LED. 3. The mounting structure for a light guide plate according to claim 1, wherein positioning and fixing of the circuit board and the light guide plate are performed by thermal caulking. 4. The light guide plate mounting structure according to claim 1, wherein an anisotropic conductor is used for electrical connection between the circuit board and the light source.