Compact optical scanning system

Abstract: Optical scanner apparatus comprising of light source (36) for projecting light on to reflecting means (42) arranged to rotate to operation, and a plurality of mirror members (48-52) for receiving in cyclic manner light reflected from said reflecting means (42), and having a further mirror member (32) having a reflecting surface (34) substantially in the form of part of the surface of a cone for receiving light reflected from said plurality of mirror members (48-52) and reflecting this light so as to provide a scan pattern for scanning coded indicia.

Description: The present invention relates to compact optical scanning systems. In present-day merchandising point-of-sale operations, data pertaining to the purchase of a merchandise item is obtained by reading data encoded indicia such as a bar code printed on the merchandise item. In order to standardize the bar codes used in various point-of-sale read out systems, the grocery industry has adopted a uniform product code (UPC) which is in the form of a bar code. Reading systems which have been constructed to read this bar code include hand-held scanners which are moved across a label bearing the bar code and stationary optical scanners normally located within the cabinet structure of a checkout counter, in which the bar code label is read when a purchased merchandise item and its associated label are moved across a window in the supporting surface of the counter constituting the scanning area of a counter, which movement is part of the process of loading the item into a baggage cart. One such scanner is known from U.S. Patent no. 4,766,298 which discloses a low-profile portable UPC optical scanner including a housing member in which is mounted on the floor portion of the housing member a light emitting element for projecting scanning light beams within the housing member and a floor-mounted multifaceted rotating mirror for directing the light beams at a plurality of floor-mounted twisted mirror members which reflect the light beams through an aperture in the cover portion of the housing member. Also U.S. Patent no. 4,797,551 discloses a compact optical scanning system which includes a housing member having a laser member mounted therein whose coherent light beam output is reflected along a shelf extending between opposite side walls of the housing member. The laser beam is directed at a mirror mounted on the shelf which reflects the laser beam at a multifaceted rotating spinner mounted on the floor of the housing member directly beneath the shelf. The rotating spinner directs the laser beam at a plurality of pattern mirrors mounted on the floor of the housing member which reflect the light beams in the form of a scan pattern through an aperture in the cover of the housing member. However, such known scanners have dimensions which are disadvantageously restrictive and which do not readily allow for portability between, and use of the scanner at, a variety of locations without sacrificing the quality of scan pattern employed. The invention therefore seeks to provide a small preferably book-sized, optical bar code scanner for generating a multiline scan pattern which can be mounted in either a vertical or a horizontal position on or in a checkout counter and which can be easily moved or carried to any location within a business establishment to provide a checkout operation at that location. According to the present invention there is provided optical scanner apparatus comprising a light source for projecting light on to reflecting means arranged to rotate to operation, and a plurality of mirror members for receiving in cyclic manner light reflected from said reflecting means, characterized by a further mirror member having a reflecting surface substantially in the form of part of the outer surface of a cone for receiving light reflected from said plurality of mirror members and reflecting this light so as to provide a scan pattern for scanning coded indicia. A particular advantage arises with the present invention in that a portable book-size scanning system can be provided which has a depth of not more than three inches (7.62 centimetres) and which can be manufactured at low cost. The invention is described further hereinafter, by way of example only with reference to the accompanying drawings in which:- Fig. 1 is a perspective view of a compact optical scanner embodying the present invention and illustrating the location of the scanning aperture together with a cable which supplies power to the scanner and also transmits electrical signals to a remote processing unit for use in obtaining the price of the merchandise item whose bar code label has been scanned; Fig. 2 is a top view of the compact optical scanner of Fig. 1 with a portion of the cover of the scanner removed and illustrating the location of the rotating multifaceted spinner and the pattern forming mirrors. Fig. 3 is a side view of the compact optical scanner of Fig. 1 with a portion of the side wall removed and illustrating the light path of the scanning light beams; and Fig. 4 illustrates the scan pattern produced by the scanner of Fig. 1. Referring now to Fig. 1, there is shown a perspective view of the optical scanner of the present invention which includes a box like-housing member 20 which in the present embodiment is 8 inches (20.32 cm) wide, 11 inches (27.94 cm) long and 3 inches (7.62 cm) in depth. Located in the cover portion 22 of the housing member 20 is a scanning window 24 through which scanning light beams are projected. Extending from the housing member 20 is a cable member 26 over which power signals are transmitted from a power source (not shown) and over which decoded data, pertaining to the data represented by the bar code on the bar code label, is transmitted to a remote processor for use in obtaining the price of the merchandise item to which the bar code label pertains. Referring now to Fig. 2, there is shown a top view of the optical scanner with the cover portion 22 removed which optical scanner includes a printed circuit board 28 mounted on the floor portion 30 of the scanning apparatus 20. Mounted on the printed circuit board 28 is a semicircular reflecting mirror member 32 (Fig. 3) having a curved cone shaped edge portion 34 on which is mounted a laser diode 36. Rotatably mounted on the drive shaft 38 of a motor 40 secured to the printed circuit board 28 and extending through the mirror member 32 is a five sided multifaceted spinner member 42 which receives the laser light beam projected along the beam axis 44 (Fig. 3) from the laser diode 36 which is oriented in a slightly upward direction towards the spinner member 42 as shown in Fig. 3. Secured to the under surface 55 of the cover portion 22 are three pattern forming mirror members 48-52 inclusive. Mounted on the mirror member 32 is a collection system which includes a mirror member 58 having an aperture 60 through which the scanning light beams from the laser diode 36 are projected. The mirror member 58 has a side portion 62 which is coated with a silver coating to reflect the reflected light beams from the scanned coded label at a collection lens member 64 mounted on the mirror member 32. The lens member 64 focuses the light beams at a photodetector 66 mounted on the mirror member 32 which generates electrical signals in response to receiving the reflected light beams in a manner that is well known in the art. In the operation of the scanning device, the laser diode 36 will output scanning light beams along the beam axis 44 towards the spinner 42 which reflects the scanning light beams at the pattern forming mirror members 48-52 inclusive. The reflecting mirror members 48 and 52 will reflect the light beams at the cone shaped edge portion 34 of the semicircular mirror member 32 which in turn reflects the light beams through the window 24 in the form of the scan pattern 54 (Fig. 4) for scanning a bar code label positioned adjacent the window. The use of the cone shaped edge portion 34 provides the mirror member 32 with a curved surface which will expand the projection of the light beams received from the mirror members 48 and 52. This produces the length of the scan lines which comprise the scan pattern 54 while still retaining the limited height of the housing member 20. The presence of the cone shaped surface of the mirror 32 will reflect the light beams at a predetermined angle to the horizontal surface of the aperture 24 which is critical to the generation of the curved scan lines 55, 57 (Fig. 4) of the scan pattern 54. The light beams reflected from the mirror members 48, 52 forming the X portion of the scan pattern comprising the scan lines 55 will be projected at an angle of 54.74 degrees. The light beams reflected from the mirror member 50 forming the scan line 57 are projected through the aperture 24 at an angle of 35.3 degrees. The formation of the scan pattern 54 is also determined by the angle to which the reflecting mirror members 48-52 inclusive are mounted to the undersurface 55 of the cover portion 22. In the present embodiment, the mirror members 48-52 inclusive are mounted at a 45 degree angle to the undersurface 55 of the cover portion 22. The light beams reflected from the bar code label on the merchandise item are directed back through the window 24, the mirror members 48-52 inclusive and one of the facets of the spinner member 42 towards the silvered side 62 of the mirror member 58. The side 62 of the mirror member 58 will reflect the light beams towards the lens member 64 which focuses the light beams at the photodetector 66. As is well known in the art, the bar code label comprises a plurality of light and dark bars (not shown) printed on a label which, when scanned by the scanning apparatus, will generate a specific pulse wave-form. The photodetector 66 will, in response to receiving the changes in the light intensity of the reflected light beams, generate electrical signals which are transmitted to the printed circuit board 28 (Fig. 2) where an A/D converter (not shown) will digitize the analog signals after which logic circuits on the circuit board 28 will process the digitized signals received and transmit the signals to a remote data terminal device (not shown) where the information is displayed over the cable 26. It will thus be seen that there is disclosed a compact optical scanner which allows a checkout operation to occur on any supporting surface in a business establishment.

Claims: Optical scanner apparatus comprising a light source (36) for projecting light on to reflecting means (42) arranged to rotate in operation, and a plurality of mirror members (48,50,52) for receiving in cyclic manner light reflected from said reflecting means (42), characterized by a further mirror member (32) having a reflecting surface (34) substantially in the form of part of the outer surface of a cone for receiving light reflected from said plurality of mirror members (48,50,52) and reflecting this light so as to provide a scan pattern for scanning coded indicia. Apparatus according to claim 1, characterized in that said reflecting surface (34) extends partly around the axis of rotation of said reflecting means (42). Apparatus according to claim 2, characterized in that said reflecting surface (34) is co-axial with said reflecting means (42). Apparatus according to claim 1, 2 or 3, characterized in that said light source (36) is mounted on said further mirror member (32) which is mounted on a support member (28). Apparatus according to any preceding claim, characterized in that said further mirror member (32) and said reflecting means (42) are mounted on a support member (28). Apparatus according to claim 4 or 5, characterized in that said reflecting means (42) comprises a multifaceted mirror member rotatably mounted by way of drive means (40) on said support member (28). Apparatus according to claim 4,5 or 6, characterized in that said support member (28) comprises a printed circuit board of the scanner. Apparatus according to any preceding claim, characterized by means (20) for housing said apparatus and having a depth not exceeding 3 inches (7.62 cm).

Inventors: JWO CHIN-HUNG, WU PAUL SHANG-YU, JWO, CHIN-HUNG, WU, PAUL SHANG-YU
Applicants: NCR INT INC, NCR INTERNATIONAL INC.
Application year: 1991
Main classification: G06K7
IPC codes: G06K7