Spread illuminating apparatus

Abstract

In a spread illuminating apparatus including: an LED at a side surface of a light conductor plate; and an FPC having a land formed on a side thereof for mounting the LED, throughholes are formed at the land, and solder is contained at least partly in each of the throughholes, whereby the LED can be mounted solidly on the FPC with a high precision in height position from the FPC, and at the same time the heat emitted from the LED can be efficiently conducted to a conductive pattern at the rear side of the FPC through an electrode terminal of the LED and the throughholes filled with the solder composed of a metallic material having a high heat conductance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a point light source and a relevant portion of a double-sided FPC in a spread illuminating apparatus according to a first embodiment of the present invention;

FIG. 2 is a top plan view of the double-sided FPC shown in FIG. 1, removing the point light source;

FIG. 3 is a cross sectional view of a point light source and a relevant portion of a double-sided FPC in a spread illuminating apparatus according to a second embodiment of the present invention;

FIG. 4 is a top plan view of the double-sided FPC shown in FIG. 3, removing the point light source; and

FIG. 5 is a perspective view of a conventional spread illuminating apparatus.

Claims

1. A spread illuminating apparatus comprising: a light conductor plate;a point light source disposed at a side surface of the light conductor plate; anda printed circuit board having a land formed on one side thereof and having the point light source mounted on the one side, wherein the point light source is attached to the land, a throughhole is formed at the land, and solder is contained at least partly in the throughhole.

2. A spread illuminating apparatus according to claim 1, wherein the solder contained in the throughhole is filled thereinto during a heating process implemented by a heating reflow soldering method.

3. A spread illuminating apparatus according to claim 1, wherein the printed circuit board is a double-sided printed circuit board which defines a front side having the point light source and a rear side opposite to the front side, and a conductive pattern section of a conductive pattern on the rear side is formed at at least an area of the rear side having the throughhole and communicates with a plated coating provided at a wall of the throughhole.

4. A spread illuminating apparatus according to claim 3, wherein a recess is formed at a portion on the front side of the printed circuit board, a bottom of the recess is constituted by a portion of the conductive pattern at the rear side, and heat conductive rein is filled in a space defined by the recess and a surface of the point light source facing the printed circuit board.