Linear light source device for image reading

• US 6,851,816 B2
• Filed: 11/06/2002
• Issued: 02/08/2005
• Est. Priority Date: 05/09/2002
• Status: Active Grant

• Current Assignee: Pixon Technologies Corp.
• Original Assignee: Pixon Technologies Corp.
• Inventors: Pang, Ming-Jen, Wu, Rong-Yaw
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Sawhney, Hargobind S.
• Application Number:
  US10/288,444
• Publication Number:
  US 20030210557A1
• Time in Patent Office: 825 Days
• Field of Search: 362/31, 362/555, 362/30, 362/236, 362/240, 362/243, 362/327, 362/339, 362/800
• US Class Current: 362/602
• 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 1/0284 in combination with a light integrating, concentrating or diffusing cavity
• CPC Class Codes: H04N 1/0289 Light diffusing elements, e.g. plates or filters optical diffusing elements per se G02B5/02

Abstract

A linear light source device for image reading. The main body of the linear light source device includes at least a light-guide bar and a light source assembly. The light-guide bar is a polygonal column with one surface having stripes thereon, acting as a reflective plane with a reflective function. The opposite plane to the reflective plane is a light-exiting plane, and all the remaining planes are reflective layers. At least one of the ends of the polygonal column is an incident plane for a light beam to enter. Light is transmitted through both of the two ends of the polygonal column (or one end with the other end acting as a reflective plane) and uniformly transmits through the light-exiting plane. The light-guided bar has a simple structure and configuration, a compact volume, a high rate of utilization in light energy, is flexibly changed in length, and is easy to manufacture with high product yield and low manufacturing cost. In addition, it can provide uniform monochromatic and colored light, with high luminance, and at a low cost.

Claims

1. A linear light source device comprising:

a light source assembly comprising a positioning plane, a reflective surface, a mounting plane, and a light-emitting diode mounted in the reflective surface; and

a light-guide bar comprising a polygonal column, a light-exiting plane, a reflective plane, and a plurality of reflective layers and further comprising at least a tail end of said light-guide bar being an incident plane for light to enter, wherein the reflective plane comprises surface stripes and is positioned opposite the light-exiting plane, and the reflective layers have a reflecting function so that the light transmitting into the incident plane and through the polygonal column and reflected off of the reflective plane and layers is transmitted out of the light-exiting plane; and

a light-reflective sheath covering a portion of the reflective layers and the reflective plane.

2. The linear light source device of claim 1, wherein the polygonal column of the light-guide bar is an octagonal column.

3. The linear light source device of claim 1, wherein a centerline of the polygonal positioning plane of the light source assembly is perpendicular to the mounting plane.

4. The linear light source device of claim 1, wherein the positioning plane of the light source assembly is tightly fit to the incident end of the light-guide bar.

5. The linear light source device of claim 1, wherein a centerline of the reflective surface of the light source assembly coincides with a light axis of the light beam.

6. The linear light source device of claim 1, wherein a rectangular opening for mounting a light-emitting diode is formed in portion of the reflective plane of the light source assembly.

7. The linear light source device of claim 1, wherein the at least one light-emitting diode of the light source assembly is mounted and uniformly distributed on the reflective surface.

8. The linear light source device of claim 1, wherein the light-exiting plane on the light-guided bar is on a surface which protrudes from the light-guide bar.

9. The linear light source device of claim 8, wherein the light-exiting plane is in a long strip profile whose length can be adjusted in accordance with application so as to achieve ideal luminous intensity.

10. The linear light source device of claim 1, wherein the reflective plane has stripes on its surface, and the stripes are treated by segmentation so that each segment has different surface roughness.

11. The linear light source device of claim 10, wherein the stripes are grooved stripes which are divided into at least two segments, the roughness of the stripes in every segment is the same but the stripes of the segments are different in depth and width.

12. The linear light source device of claim 1, wherein the reflective plane of the polygonal column has stripes on its surface, and the stripes are treated by segmentation such that surface roughness is relatively smooth near the light source while the surface roughness increases gradually as the stripes are a located farther from the light source so as to improve the uniformity of the light beam transmitting out of the light-exiting plane.

13. The linear light source device of claim 1, wherein the surface, of the reflective plane of the polygonal column is film-coated with silver-white light-reflective paint.

14. The linear light source device of claim 1, wherein another end plane of the polygonal column is a tail end plane for reflecting the light beam that is incident to the plane, back into the main body of the octagonal main body.

15. The linear light source device of claim 1, wherein a surface of the tail end plane of the light-guided bar is film-coated with silver-white light-reflective paint.