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

• US 20070153505A1
• Filed: 03/07/2007
• Published: 07/05/2007
• Est. Priority Date: 07/09/2001
• Status: Abandoned Application

• Current Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Original Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Inventors: Saito, Tomihisa, Uemura, Yoshiyuki
• Application Number:
  US11/714,948
• Publication Number:
  US 20070153505A1
• Time in Patent Office: Days
• US Class Current: 362/187
• CPC Class Codes: H04N 1/02815 Means for illuminating the original, not specific to a particular type of pick-up head
• CPC Class Codes: H04N 1/0282 Using a single or a few point light sources, e.g. a laser diode
• CPC Class Codes: H04N 1/02835 in combination with a light guide, e.g. optical fibre, glass plate light-guides per se G02B6/00
• CPC Class Codes: H04N 1/02885 Means for compensating spatially uneven illumination, e.g. an aperture arrangement
• CPC Class Codes: H04N 1/0318 Integral pick-up heads, i.e. self-contained heads whose basic elements are a light-source, a lens array and a photodetector array which are supported by a single-piece frame
• CPC Class Codes: H04N 1/40056 Circuits for driving or energising particular reading heads or original illumination means H04N1/401, H04N1/407 take precedence
• CPC Class Codes: H04N 2201/02462 Illuminating means
• CPC Class Codes: H04N 2201/02485 Dedicated element, e.g. bracket or arm
• CPC Class Codes: H04N 2201/02495 Constructional details not otherwise provided for, e.g. for ease of assembly, allowing access to the scanning elements, integrated reinforcing members
• CPC Class Codes: H04N 2201/03112 Light source
• CPC Class Codes: H04N 2201/03158 Heat radiator
• CPC Class Codes: H04N 2201/04767 by controlling the timing of the signals, e.g. by controlling the frequency o phase of the pixel clock
• CPC Class Codes: Y10S 362/80 Light emitting diode

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 21a for mounting a light-emitting device. The lead frame 22 comprises a lead terminal section 22a, an inner lead section 22c, and a light-emitting device mounting and connecting section 22b which is exposed within the open window 21a. The light-emitting devices 23a, 23b, and 23c are bonded with the light-emitting device mounting and connecting section 22b, and electrodes of the light-emitting devices and the lead frame are connected by a metal wire 24, wherein the open window 21a 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.

Claims

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. 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

5. 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.

6. 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.

7. An image reading device comprising the illumination device according to claim 5, 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.

8. An image reading device comprising the illumination device according to claim 6, 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.

3. 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.

4. The light-emitting unit according to claim 3, 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 3.

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 3.