Bar code scanner with diffusion filter and plural linear light source arrays

• US 4,743,773 A
• Filed: 08/21/1985
• Issued: 05/10/1988
• Est. Priority Date: 08/23/1984
• Status: Expired due to Term

• Current Assignee: NEC Infrontia Corporation (NEC Corporation)
• Original Assignee: Nippon Electric Industry Company Limited
• Inventors: Sekiguchi, Ichiro, Katana, Yukio, Goto, Masao
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Ruoff, Jessie L.
• Application Number:
  US06/768,076
• Time in Patent Office: 993 Days
• Field of Search: 250/566, 250/568, 250/221, 250/226, 250/236, 235/472, 235/462, 350/452
• US Class Current: 235/462.07
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10742 including a diffuser for diffusing the light from the light source to create substantially uniform illumination of the target record carrier

Abstract

The present invention provides a bar code scanner applicable for use to scan various bar codes of different standards and sizes. Any malfunction due to nonuniform illumination of the bar code or maloperation can be prevented, and also the light source may not be normally turned on. This bar code scanner is usable as held by hand or fixed as desired.

The opening of the scan head of the inventive bar code scanner is formed polygonal, and high light-transmission diffusion filter is provided between the light source and the opening. The light source consists of spot light sources disposed in plural linear arrays including the ones which are normally on for sensing the proximity to a bar code and the others which are turned on and off depending on whether the scan head is near or far from a bar code.

Furthermore, the scan head enclosure consists of a gripping portion for the operation of the scanner as held by hand and a flat bottom portion for use in operating the scanner as fixed; both portions are integrally formed to be the enclosure in which a light source, photodetector, decoder and interface.

Claims

1. A bar code scanner, housed in a lightproof enclosure at one end of which an opening is formed, said scanner having a scan head for illuminating a bar code facing said opening from a light source disposed inside said opening, a photodetector provided within said enclosure and positioned to receive light reflected from a bar code in front of said opening, said photodetector comprising a CCD image sensor or a plurality of photodetecting elements, said photodetector converting the light into an electrical signal, and means for processing the electrical signal, for thereby identifying said bar code,

said opening of the scan head being defined by a straight front central portion of said enclosure and right and left lateral portions, said right and left lateral portions joining the opposite ends, respectively, of the front central portion at an obtuse sweepback angle.

2. A bar code scanner, housed in a lightproof enclosure at one end of which an opening is formed, in which a bar code facing said opening is illuminated from a light source consisting of high brightness and directionality LEDs and which is so located inside said opening that an optical axis of light projection intersects obliquely an optical axis of light reception, a photodetector provided within said enclosure and positioned to receive light reflected from a bar code at said opening, said photodetector comprising a CCD image sensor or a plurality of photodetecting elements, and means for processing an electrical signal from said photodetector to identify said bar code.

a high light transmission diffusion filter interposed between said light source and opening and parallel to the front face of said light source.

3. A bar code scanner, housed in a lightproof enclosure at one end of which an opening is formed, having a scan head which illuminates a bar code facing said opening from a light source disposed inside said opening, a photodector provided within said enclosure and positioned to receive light reflected from a bar code at said opening, said photodetector comprising a plurality of CCD image sensors or photodetecting elements, said photodetector converting the light into an electrical signal, and means for processing the electrical signal, for thereby identifying said bar code,

said light source being a plural-array type comprised of a plurality of linear light sources comprising a plurality of high brightness and directionality spot light sources disposed with predetermined spacings in a line, said linear light sources being arranged in a plurality of rows in a single plane, whereby the illuminated area covers all the bars of a bar code independently of the inclination of the scan head to the bar code.

4. A bar code scanner in which a reflected light from a bar code surface is detected by a photodetector to recognize the data, having a light source for illuminating the bar code surface, said light source comprising:

a plurality of light emitting elements forming a linear array of light emitting elements;

a plurality of resistor elements connected to said light emitting elements, respectively, to limit the amount of current flowing through said respective light emitting elements;

switching elements connected in series with determined ones of said light emitting elements, respectively, whereby at least one of said light elements is normally continually energized;

a control circuit to turn on and off said switching elements;

said light emitting elements which are normally energized being used for sensing the proximity to a bar code, said control circuit being connected to receive the output signal from the photodetector in response to the reflected light from said normally energized light emitting elements and outputting, when the proximity to the bar code is recognized, a control signal to turn on said switching elements for a predetermined length of time, whereby when the proximity to the bar code is detected by the normally energized photodetector, all the light emitting elements are turned on to scan the bar code.

5. A bar code scanner, comprising a light source to illuminate the surface of a bar code, an optical system to collect the scattered light on the bar code surface, a photoelectric transducer to convert the light collected by said optical system into an electrical signal, a decoder to shape the waveform of the electrical signal thus photoelectrically converted and analyze the information such as figures and letters expressed by the bar code, and an interface to interface the data from said decoder with an external device;

said bar code scanner further comprising a scan head enclosure enclosing at least said light source, optical system, and photoelectric transducer, said enclosure being portable and being provided at one end thereof with an opening serving as the path for the projected light and reflected light, said enclosure having a central through hole and also a gripping portion for handling said scan head when it is held by hand, said gripping portion extending from the top of said enclosure to the upper portion of said horizontal through hole;

said enclosure further having a flat bottom for using said scan head as a fixed device, said flat bottom is provided under the lower portion of said horizontal through hole and defining the lowermost portion of said scanner, whereby the bar code can be scanned by the bar code scanner either when it is held by the hand or is fixed.

6. A bar code scanner as set forth in claim 5, said enclosure housing also the decoder and interface.