Light-emitting unit and illumination device and image reading device using light-emitting unit

Abstract

A light-emitting unit 20 has a light-emitting unit board 21 made of resin provided with a lead frame 22 . The light-emitting unit board 21 is also provided with an open window 21 a for mounting a light-emitting device. The lead frame 22 comprises a lead terminal section 22 a , an inner lead section 22 c , and a light-emitting device mounting and connecting section 22 b which is exposed within the open window 21 a . The light-emitting devices 23 a , 23 b , and 23 c are bonded with the light-emitting device mounting and connecting section 22 b , and electrodes of the light-emitting devices and the lead frame are connected by a metal wire 24 , wherein the open window 21 a is sealed by transparent resin. The lead frame 22 is made of iron-containing copper to improve heat radiation performance of the light-emitting unit board. By increasing maximum current to be supplied to the light-emitting diodes, it is possible to increase illumination brightness and to attain speedup of image reading.

1 . A light-emitting unit having a light-emitting device mounted on a light-emitting unit board which is provided with a lead frame, wherein the lead frame is made of a copper alloy or an aluminum alloy of which the heat conductivity is 250 W/(m·K) or more.  
     
     
         2 . (CANCELED)  
     
     
         3 . The light-emitting unit according to  claim 1 , wherein the copper alloy is iron-containing copper having composition of Fe: 0.02˜0.5 wt %; P: 0.005˜0.10 wt %; and the rest: Cu  
     
     
         4 . The light-emitting unit according to claims  claim 1 , wherein when thickness of the lead frame is t (mm), thickness of the light-emitting unit board is T (mm), thickness of the light-emitting device is D (mm), and height of a bonding wire is d (mm), the relationship among them is 0.1 mm≦t≦(T−D−d).  
     
     
         5 . A light-emitting unit having light-emitting devices mounted on a light-emitting unit board which is provided with a lead frame, wherein the lead frame surface is provided with silver plating, and at least a translucent light-emitting device of the light-emitting devices is bonded with the lead frame by transparent resin.  
     
     
         6 . A light-emitting unit having light-emitting devices mounted on a light-emitting unit board which is provided with a lead frame, wherein at least a translucent light-emitting device of the light-emitting devices is bonded with the lead frame by white resin.  
     
     
         7 . A light-emitting unit having a light-emitting device mounted on a light-emitting unit board which is provided with a lead frame, wherein the light-emitting unit board is made of resin of which the heat resistant temperature is higher than a melting point of lead-free solder which is used when the lead frame is soldered onto an electric circuit.  
     
     
         8 . The light-emitting unit according to  claim 7 , wherein the resin is polyphthalamide resin, polyphenylene sulfide resin, or liquid crystal polymer.  
     
     
         9 . An illumination device designed to emit light incident from a light-emitting unit which is provided on an end face of a bar-shaped light guide in the longitudinal direction from a light-emitting surface provided along the longitudinal direction while reflecting the light by the inner surface of the bar-shaped light guide, wherein the light-emitting unit is specified by  claim 1 .  
     
     
         10 . An illumination device designed to emit light incident from a light-emitting unit which is provided on a side of a plate-shaped light guide in the direction of the thickness from the upper or lower surface of the plate-shaped light guide while reflecting the light by the inner surface of the plate-shaped light guide, wherein the light-emitting unit is specified by  claim 1 .  
     
     
         11 . An image reading device comprising the illumination device according to  claim 9 , a line image sensor, and a rod lens array for converging the reflected light or transmitted light from a document on the line image sensor, wherein each of them is incorporated within a frame.  
     
     
         12 . An image reading device comprising the illumination device according to  claim 10 , a line image sensor, and a rod lens array for converging the reflected light or transmitted light from a document on the line image sensor, wherein each of them is incorporated within a frame.  
     
     
         13 . An illumination device designed to emit light incident from a light-emitting unit which is provided on an end face of a bar-shaped light guide in the longitudinal direction from a light-emitting surface provided along the longitudinal direction while reflecting the light by the inner surface of the bar-shaped light guide, wherein the light-emitting unit is specified by  claim 5 .  
     
     
         14 . An illumination device designed to emit light incident from a light-emitting unit which is provided on an end face of a bar-shaped light guide in the longitudinal direction from a light-emitting surface provided along the longitudinal direction while reflecting the light by the inner surface of the bar-shaped light guide, wherein the light-emitting unit is specified by  claim 6 .  
     
     
         15 . An illumination device designed to emit light incident from a light-emitting unit which is provided on an end face of a bar-shaped light guide in the longitudinal direction from a light-emitting surface provided along the longitudinal direction while reflecting the light by the inner surface of the bar-shaped light guide, wherein the light-emitting unit is specified by  claim 7 .  
     
     
         16 . An illumination device designed to emit light incident from a light-emitting unit which is provided on a side of a plate-shaped light guide in the direction of the thickness from the upper or lower surface of the plate-shaped light guide while reflecting the light by the inner surface of the plate-shaped light guide, wherein the light-emitting unit is specified by  claim 5 .  
     
     
         17 . An illumination device designed to emit light incident from a light-emitting unit which is provided on a side of a plate-shaped light guide in the direction of the thickness from the upper or lower surface of the plate-shaped light guide while reflecting the light by the inner surface of the plate-shaped light guide, wherein the light-emitting unit is specified by  claim 6 .  
     
     
         18 . An illumination device designed to emit light incident from a light-emitting unit which is provided on a side of a plate-shaped light guide in the direction of the thickness from the upper or lower surface of the plate-shaped light guide while reflecting the light by the inner surface of the plate-shaped light guide, wherein the light-emitting unit is specified by  claim 7.