Hand-held plastic optical fiber linear scanner for reading color images formed on a surface

• US 6,075,240 A
• Filed: 07/30/1998
• Issued: 06/13/2000
• Est. Priority Date: 07/30/1998
• Status: Expired due to Term

• Current Assignee: Association For Public Health Service, NEC Corporation
• Original Assignee: NEC USA (NEC Corporation)
• Inventors: Fujieda, Ichiro, Schweitzer, Allan, Wang, Ting, Li, Yao, Watanabe, Kojiro
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US09/124,832
• Time in Patent Office: 684 Days
• Field of Search: 250/234, 250/235, 250/566, 250/208.1, 250/227.11, 250/227.2, 250/227.26, 250/231.18, 250/237.14, 235/472.01, 235/472.02, 235/472.03, 235/462.45, 382/313, 358/473, 358/474, 358/484
• US Class Current: 250/234
• CPC Class Codes: G02B 6/06 the relative position of the fibres being the same at both ends, e.g. for transporting images
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: H04N 1/107 with manual scanning
• CPC Class Codes: H04N 1/48 Picture signal generators for halftone screening H04N1/52

Abstract

A hand-held optical scanner for reading color images formed on a document. The scanner head is all-optical and contains no electronics. Optical fiber bundles couple the scanner head to a remote opto-electronic module containing a linear or a 2D sensor array for converting optical signals, reflected from the document, to electrical signals for transmission to a computer display, etc. By using side coupling, the transmitted and reflected light for each pixel travels through the same optical fiber without the need for a beam splitter. The optical fibers are used for the functions of image scanning, position encoding, and signaling a computer which assigns each one of incoherently arranged optical fibers to one of the functions.

Claims

1. An optical scanner for scanning and reading a color image formed on a surface, comprising:

a hand-held scanner head;

an optoelectronic module, separate from said scanner head, and located at a distance from said scanner head, for converting impinging light signals to electrical signals;

light source means, separate from said scanner head and located at a distance therefrom, for generating red, blue and green light beams; and

a bundle of individual plastic optical fibers extending from said scanner head to said optoelectronic module and to said light source means,

first ends of said optical fibers being secured in said scanning head and arranged in a linear array for scanning the color image upon movement of said hand-held scanner head,

opposite ends of said optical fibers being coupled to said optoelectronic module and to said light source means,

whereby a light beam is transmitted from said light source means via a given fiber to said surface, is reflected from the image thereon, and is returned via said same given fiber to said module to produce electrical signals representative of the scanned image.

2. The optical scanner as defined in claim 1, wherein each fiber has a side-coupler for receiving the transmitted light beam.

3. The optical scanner as defined in claim 1, wherein said scanner head carries an all-optical encoder for determining the movement of the scanner head and the position of the scanner head relative to the surface.

4. The optical scanner as defined in claim 3, wherein said scanner head carries all-optical fiber switches for controlling the scanning and position-encoding operations of the scanner, and for controlling ON/OFF operation of the scanner.

5. The optical scanner as defined in claim 1, wherein said opto-electronic module comprises multi-apertured photodiodes for converting optical signals to electrical signals.

6. The optical scanner as defined in claim 5, wherein the photodiodes are formed in a 2D array on a transparent glass substrate.

7. The optical scanner as defined in claim 1, wherein said optical electronic module comprises a linear array of photodetectors.

8. The optical scanner as defined in claim 1, wherein the first and opposite ends of the optical fibers are randomly disposed relative to each other.

9. The optical scanner as defined in claim 1, wherein said optoelectronic module comprises a plurality of photodetectors, and wherein said optical scanner further comprises computer means for correlating the respective first and opposite ends of each fiber, and for assigning each fiber to one or more detector pixels, where the pixel subsets assigned to individual fibers are disjoint.

10. The optical scanner as defined in claim 1, wherein a center portion of each fiber is thinner than the tips of the fiber, thereby providing increased flexibility to the fiber bundle.

11. An all-optical hand-held scanner head for use in a color image scanning system including light detecting means for detecting image light signals reflected from the image when the image is irradiated with transmitted colored light signals, said scanner head comprising:

an extended housing having a scanning surface;

a bundle of elongated optical fibers mounted in said housing, and having respective optical fiber tips exposed at said scanning surface, each of said optical fibers having an optical side coupling for inputting the transmitted colored light signals;

optical rotary encoder means, mounted on said housing, for reflecting coded light signals indicative of the displacement of said scanner head along said image; and

manually operated optical fiber switch means, mounted in said housing, for reflecting function-defining light signals,

a first set of said optical fiber tips being linearly disposed along the length of said scanning surface, and being dedicated to scanning the image by directing the transmitted colored light signals to said image and returning corresponding said reflecting image light signals via said bundle to the light detecting means,

a second set of said optical fiber tips being dedicated to said rotary encoder means for directing the transmitted coded light signals to said rotary encoder means and returning the reflected coded light signals via said bundle to said light detecting means, and

a third set of said optical fiber tips being dedicated to said optical fiber switch means for directing the transmitted colored light signals to said optical fiber switch means and returning the reflected function-defining light signals via said bundle to said light detecting means,

wherein corresponding transmitted and reflected light signals travel in opposite directions in the same optical fiber.

12. The scanner head as defined in claim 11, further comprising a protective layer covering said optical fiber tips.

13. The scanner head as defined in claim 12, wherein the protective layer is a transparent silica coating having a thickness of approximately 12 μ

m.

14. The scanner head as defined in claim 12, wherein the protective layer is a transparent glass layer having a thickness of approximately 100 to 150 μ

m.