Source: http://www.freepatentsonline.com/6578767.html
Timestamp: 2020-02-18 18:34:20
Document Index: 304827484

Matched Legal Cases: ['art 11', 'art 11', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 51']

Low cost bar code reader - Symbol Technologies, Inc.
United States Patent 6578767
Barkan, Ed (Miller Place, NY)
09/616564
235/462.2, 235/462.21, 235/462.22, 235/462.3
A61B5/055; A61B6/03; G06K7/10; G06T1/00; G06T7/00; (IPC1-7): G06K7/10
235/462.43, 235/462.3, 235/462.21, 235/462.2, 235/462.22
Download PDF 6578767 PDF help
6360949 Retro-reflective scan module for electro-optical readers 2002-03-26 Shepard et al. 235/462.37
6315204 Optical code reader and methods and articles therefor 2001-11-13 Knighton et al. 235/462.43
6186400 Bar code reader with an integrated scanning component module mountable on printed circuit board 2001-02-13 Dvorkis et al. 235/462.45
6102293 Optical scanning system minimizing average laser power and improving aiming 2000-08-15 Barkan et al. 235/462.2
6036094 Hand-held optical scanner for reading two-dimensional bar code symbols and the like 2000-03-14 Goldman et al. 235/462
6000619 Scanner assembly 1999-12-14 Reddersen et al. 235/462.43
5949068 Optical reader for scanning optical indicia by way of varying object distance 1999-09-07 Stoner et al. 250/234
5814804 Optical scanner activated with position locator 1998-09-29 Kostizak 235/472.01
5448050 Integrated bar code reading and location mouse 1995-09-05 Kostizak 235/462.43
5319184 Tip assembly for a bar code scanner 1994-06-07 Gilpin et al. 235/462.43
5142131 Hand-held bar code reader 1992-08-25 Collins, Jr. et al. 235/462.46
ALAN ISRAEL (KIRSCHSTEIN OTTINGER ISRAEL & SCHIFFMILLER, P.C. 489 FIFTH AVENIE, NEW YORK, NY, 10017-6105, US)
1. A bar code reader for electro-optically reading a bar code symbol on a target, comprising: a) a housing having a bottom wall facing the target, and configured to be held and slidably moved by a user across the target, during reading; b) a plurality of feet on, and extending from, the bottom wall for slidably engaging the target during the sliding movement of the housing; c) a printed circuit board within the housing above the bottom wall; d) an aperture extending through the bottom wall; e) a light source on the board for emitting light toward the bottom wall and through the aperture for reflection from the symbol on the target; f) a detector on the board for detecting light reflected from the symbol, and for generating an electrical signal corresponding to the symbol; and g) said aperture extending through one of the feet for positioning the aperture over the symbol during the sliding movement of the housing.
FIGS. 1a and 1b show a top and side views of one embodiment of a bar code reader according to the invention;
FIGS. 5a and 6a illustrate a scanning operation on curved surfaces with an embodiment of the invention that utilizes flat-bottom feet in the bottom part of the reader housing;
FIGS. 5b and 6b illustrate a scanning operation on curved surfaces with an embodiment of the invention that utilizes sloped bottom-surface feet in the bottom part of the reader housing;
FIGS. 9a, 9b, 9c and 9d show bottom, side and top views of yet another embodiment of the invention, also showing the outline of the circuit board and the internal components inside the device housing.
One embodiment of the low-cost bar scanner according to the present invention is illustrated in FIGS. 1a and 1b and comprises a bar scanning device 10 in a shape that is similar to a small mouse pointing device for a personal computer. The scanning device 10 has an outer housing 11 that consists of a lower part 11b and an upper part 11a (a cover). While present invention is not limited to that particular physical shape and other shapes for the low-cost bar scanner according to the present invention are possible, the mouse shape offers several advantages. First, this shape enjoys great recognition and association with high-tech application by the public. Second, the mouse-shaped bar code scanning device of the present invention may also include components of a computer mouse and have an additional use as such. Third, the shape of the housing assures that the scanner is properly oriented with respect to the bar code.
FIGS. 2a-2c show an alternative housing design for the bar code scanning device of the present invention. It is understood that the scanner structure inside the housing, shown in FIGS. 2a-2c, can also be used in the embodiment of FIGS. 1a and 1b.
As shown in FIGS. 2a and 2b, the bar scanning device 20 has a housing 21 that holds the circuit board 22 which carries on its underside the surface mounted LED 24 and the photodiode 25, or another type of a photodetector. In an alternative embodiment, the LED (or another light source) and the photodiode may be installed on separate circuit boards that are connected together, or either of them mounted separately on a flex-strip that is soldered to the main board. The surface mounted LED 24 and the photodiode 25 are standard parts that are currently available from several manufacturers. They can be installed on the circuit board with standard pick and place machinery, as are all other electrical components in the scanner. This process is entirely automated and is well known in the electronics industry. No special care is required when placing the photodiode and LED on the board. The position tolerance of standard machinery is adequate.
As further illustrated in FIGS. 2b and 2c, the circuit board 22 of a bar scanning device 20, carrying the photodiode 25, the LED 24, and any other desired circuitry, may be placed into the lower part of the housing 21 with the LED and photodiode on the bottom of the board, aiming downward. Directly below the LED, there is a small aperture 26 in the bottom part 21b of the housing 21. When the LED is illuminated, it projects light towards the bottom of the housing. Some of the light travels through the aperture 26 of the scanning module 200, which is shown in more detail in FIG. 3. The LED 24, which has an integral lens, projects a light beam that diverges at an angle of several degrees. Therefore, even if the LED 24 is tilted slightly when soldered, the aperture will still be illuminated. It is understood that, in accordance with the present invention, the circuit board carrying the photodiode and LED may be placed in the upper part of the housing as well, or any other portion of the housing, so long as it is spaced apart from the aperture.
Referring to FIG. 3, the photodiode 25 is positioned on the underside of the circuit board 22 in close proximity to the LED 24. The LED 24 and the photodiode 25, however, are preferably separated by a wall of opaque material, the light baffle 27, which prevents light from passing directly from the LED to the photodiode. This light baffle assures that only light reflected from the bar code (or other type of symbol that is being scanned) can reach the photodiode. The bottom part 21b of the housing 21 should be preferably of a dull black or some other dark color in order to minimize the amount of light reflected back to the detector.
The floor 28 of the bottom part 21b of the scanning module 200 below the detector should be sloped so as to prevent specular reflection of LED light toward the detector. Directly below the LED 24, there is a small aperture 26 in scanning module 200 and the bottom part 21b of the housing 21. In order to avoid being blocked by dirt or debris, the aperture 26 may be covered (for example, on the bottom or outside of the housing) with a thin film of transparent material 23 that acts as an exit window. One of several ways of achieving this is with a transparent self-adhering sticker applied to the bottom of the housing. The sticker could be made with an adhesive free area that is positioned over the aperture.
Referring to FIGS. 2a, 2b and 2c, the scanner 20 is placed on a symbol to be scanned, with the aperture 26 to one side of the symbol. The user then gently grip the sides of the housing 21 and manually moves it, sliding the aperture 26 entirely across the bar code symbol, so that it crosses every bar and space in the symbol. As the scanner moves, the aperture is sometimes positioned over dark bars in the symbol, and sometimes over light spaces. When positioned over spaces, light from the LED 24 passes through the aperture 26, strikes the space and reflects back through the aperture into the housing. Some of this light strikes the photodiode 25, causing it to produce a current.
The aperture 26 in the bottom part 21b of the housing 21 is preferably around the size of the narrowest bar in any symbol that is to be decoded. It is, however, possible to decode even when the hole is smaller or a little bigger than the bar (or a space between bars).
In the embodiment of the present invention, as illustrated in FIGS. 2a and 2c, the housing 21 has three small protrusions or feet 29a, 29b and 29c on the bottom part 21b of the housing 21. When the scanner is placed on a flat surface, only these three feet touch the surface. Two feet 29b and 29c are preferably located at the end of the housing opposite the scanning aperture, and are spread as far apart as the housing size permits in order to provide stability. The third foot 29a is preferably concentric with the scanning aperture 26. In other words, the scanning aperture 26 projects through the third foot 29a near the center of the foot. When scanning, only these three feet contact the surface of the bar code, or the item carrying the bar code. When scanning a symbol on an uneven (but generally flat) surface, the three feet construction assures that the aperture stays in contact with the symbol and the aperture does not lift away from the surface of the bar code, which would reduce the performance of the scanning device.
Alternatively, the entire bottom part 21b of the scanner housing 21 can be flat, with no protrusions or feet. Since this increases fiction, it is preferably made of a low-friction material.
While other types and color may be used for the housing 21, the bottom part 21b of the housing 21 is preferably injection molded out of black plastic. The lower part of the housing includes the scanning aperture 26, the light baffle 27, and sloping floor area below the photodiode 25. There are also walls, molded as part of the lower housing, that rise up close to or touching the bottom of the circuit board. These walls surround the LED and photodetector excluding ambient light. The walls are preferably made to have a rough texture to minimize internal reflections.
The upper part of the housing 21 may be made of any color that is desired. When the scanner is assembled, the circuit board is placed on locating features integral with the bottom part 21b of the housing 21. Then the upper part (the cover) of the housing is snapped in place. The upper part carries features that hold the circuit board in place. With snaps 21c, shown in FIGS. 2b and 3, that are well known in the art, no screws or glue are necessary to hold the top and bottom of the housing together.
Referring to FIG. 5a, the scanner 50 utilizes flat-surface feet for the scanner, the aperture 56 is in the center of a flat bottom foot 59a extending from the bottom part 51b of the housing. When this embodiment of the invention is used on curved surface, as shown in FIG. 6a, the scanner is tilted with respect to the symbol surface 600, and the reading aperture 56 is lifted off the reading surface, thereby interfering with scanning operation of the device. In another embodiment of the scanner according to present invention, as shown in FIGS. 5b and 6b, the bottom surface of the foot 59a′ (and other feet that are not shown) is curved, sloping upward away from the aperture 56′. In this embodiment, the performance of the scanner on curved surfaces is improved, because the reading aperture 56′ is not lifted off the symbol surface 600 as much, and remains close to perpendicular relatively to the symbol surface. The sloping surface of the foot 59a′ allows scanner to read at tilt angles exceeding 15 degrees.
In an alternative embodiment to that shown in FIGS. 5b and 6b, the entire bottom surface of the scanner housing can be curved, with no protrusions or feet. In order to reduce friction, the bottom surface in such embodiment is preferably made of a low-friction material.
FIGS. 4a and 4b depict the electrical schematics of a circuit for use with the scanner. FIG. 4a illustrates an LED driving circuit, while FIG. 4b illustrates signal processing circuitry for digitizing the output of the photodiode. The driving circuit of FIG. 4a is generally self-explanatory and easily understood by one skilled in the art. The schematic of FIG. 4b is described below.
A cross sectional view of a pistol-shaped wand scanner according to the present invention is illustrated in FIG. 7. The wand scanner 70 comprises a housing 71, that holds the circuit board 72 (PCB board), with LED 74 and photodiode 75 mounted on the circuit board. Directly below the LED 74, there is a small aperture 76 in the neck portion 71b of the wand scanner 70. When the LED is illuminated, it projects light towards the bottom surface of the neck portion 71b. Another embodiment of a pistol-shaped wand scanner according to the present invention is illustrated in FIG. 8, as having the LED 84 and the photodiode 85 mounted on the circuit board 82, over the small aperture 86 in the neck portion 81b of the wand scanner 80. The elongated reading aperture 76 or 86 of the embodiments shown in FIGS. 7 and 8, respectively, allows to maintain proper orientation during the scan, and provides for improved tilt tolerance and depth of focus when reading both flat and curved surfaces. Baffles 77 and 87 in FIGS. 7 and 8 isolate the LEDs from the photodiode as in the previous embodiments.
Another type of scanner 90 in accordance with the present invention is illustrated in FIGS. 9a, 9b, 9c and 9d, showing bottom, side, top and detail views, respectively, of a pen-type scanner. The LED 94 and the photodiode 95, separated by the baffle 97 are mounted on the circuit board 92. This embodiment also comprises a fold mirror 99 that directs light through the aperture 96. Light from the LED 94 is reflected by the fold mirror 99 through the aperture 96, and reflected light is directed by the mirror 99 to the photodiode 95. The aperture 96 may be protected by a transparent tape 93 that is inserted into the tip of the scanner over the aperture 96 as shown in FIG. 9d.
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