Laser scanning code symbol reading system providing control over length of laser scan line projected onto a scanned object using dynamic range-dependent scan angle control
First Claim
1. A method of reading code symbols using a laser scanning code symbol reading system having a working distance, said method comprising the steps of:
- (a) supporting, adjacent an object with a code symbol, a hand supportable laser scanning code symbol reading system having a scan line data buffer;
(b) estimating a distance of said object from said reading system, and generating data representative of said estimated distance;
(c) projecting a laser scanning beam, wherein the laser scanning beam is swept through a scan angle while maintaining a constant scan line length projected onto said object scanned by the laser scanning beam as the estimated distance of said object from said laser scanning code symbol reading system changes over time;
(d) detecting the intensity of laser light reflected/scattered from a scanning field of said laser scanning code symbol reading system during the scan sweep of the laser scanning beam across said scanning field and any object in said scanning field, and generating a scan data signal representative of the detected laser light;
(e) collecting a line of scan data over a sweep of the laser beam across the scanning field and any object therein, and buffing the collected line of scan data; and
(f) decode processing said line of scan data collected and buffered in step (e) in an attempt to read any code symbol represented in said line of scan data, and when a code symbol is read within said line of scan data, then generating and transmitting symbol character data, corresponding to said decoded code symbol, to an intended destination.
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Accused Products
Abstract
Method of and system for reading bar code symbols using a hand-supportable laser scanning bar code symbol reading system supporting an improved level control over the length of laser scan lines projected onto scanned objects, at any instant in time, in a manner dependent the detected location, distance or range of the scanned object in the scanning field of the system during system operation. The length characteristics of the laser scan line are controlled by setting the laser scan sweep angle as a function of detected or estimated distance or range of the object from the system. In the illustrative embodiment, the laser scan sweep angle is controlled by supplying a drive current to the scanning mechanism, as a function of detected or estimated distance or range of the object from the scanning system.
401 Citations
20 Claims
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1. A method of reading code symbols using a laser scanning code symbol reading system having a working distance, said method comprising the steps of:
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(a) supporting, adjacent an object with a code symbol, a hand supportable laser scanning code symbol reading system having a scan line data buffer; (b) estimating a distance of said object from said reading system, and generating data representative of said estimated distance; (c) projecting a laser scanning beam, wherein the laser scanning beam is swept through a scan angle while maintaining a constant scan line length projected onto said object scanned by the laser scanning beam as the estimated distance of said object from said laser scanning code symbol reading system changes over time; (d) detecting the intensity of laser light reflected/scattered from a scanning field of said laser scanning code symbol reading system during the scan sweep of the laser scanning beam across said scanning field and any object in said scanning field, and generating a scan data signal representative of the detected laser light; (e) collecting a line of scan data over a sweep of the laser beam across the scanning field and any object therein, and buffing the collected line of scan data; and (f) decode processing said line of scan data collected and buffered in step (e) in an attempt to read any code symbol represented in said line of scan data, and when a code symbol is read within said line of scan data, then generating and transmitting symbol character data, corresponding to said decoded code symbol, to an intended destination.
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2. A laser scanning code symbol reading system, comprising:
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a housing with a light transmission window; a laser scanning module, disposed in said housing, for scanning, during each scanning cycle, a laser beam across a laser scanning field defined external to said symbol reading system, and along a laser scan line on a scanned object in said laser scanning field; light collection optics, disposed in said housing, for collecting light reflected/scattered from the scanned object in said laser scanning field; a photo-detector, disposed in said housing, for detecting the intensity of collected light from said laser scanning field, and generating an analog scan data signal corresponding to said detected light intensity during laser scanning operations, during each said scanning cycle; a scan data signal processor, disposed in said housing, for processing said generated analog scan data signal, and generating a line of scan data for each said scanning cycle; wherein said scan data signal processor further includes a module for processing said analog scan data signal so as to automatically detect whether an object is present in a near-portion of said scanning field or a far-portion of said scanning field, wherein said module of said scan data signal processor is configured to estimate the distance of the object in said laser scanning field from said symbol reading system, and generate data representative of said estimated distance; wherein said laser scanning module further projects said laser scanning beam through said light transmission window, comprising the laser scanning beam having a scan angle; a scan data buffer, disposed in said housing, for buffering each said line of scan data during each said scanning cycle; a programmed processor, disposed in said housing, for processing each said line of scan data buffered in said scan data buffer during each said scanning cycle to decode any code symbol represented in said scan data, and generate symbol character data representative of said decode code symbol, and transmitting said symbol character data to an intended destination; and a system controller, disposed in said housing, for controlling operations within said laser scanning code symbol reading system to maintain a length of the laser scan line projected onto the scanned object within predetermined limits as the estimated distance of the scanned object from said laser scanning code symbol reading system changes over time, wherein said laser scanning code symbol reading system comprises a near-field laser source and a far-field laser source, and said system controller is configured to activate said near-field laser source in response to detecting that the object is present in the near-portion of said scanning field, and activate said far-field laser source in response to detecting that the object is present in the far-portion of said scanning field. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of reading code symbols using a laser scanning code symbol reading system having a working distance, said method comprising the steps of:
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(a) supporting, adjacent an object with a code symbol, a hand-supportable laser scanning code symbol reading system having a scan line data buffer; (b) automatically detecting whether said object is present in a near-portion of a scanning field or a far-portion of said scanning field, comprising estimating a distance of said object from said symbol reading system, and generating data representative of said estimated distance; (c) projecting a laser scanning beam, wherein the laser scanning beam is swept through a scan angle while maintaining a scan line length projected onto said object scanned by the laser scanning beam within predetermined limits as the estimated distance of said object from said laser scanning code symbol reading system changes over time, wherein said laser scanning code symbol reading system comprises a near-field laser source and a far-field laser source, and wherein step (c) comprises; activating said near-field laser source in response to detecting that said object is present in said near-portion of said scanning field, and activating said far-field laser source in response to detecting that said object is present in said far-portion of said scanning field; (d) detecting the intensity of laser light reflected/scattered from said scanning field of said laser scanning code symbol reading system during the scan sweep of the laser scanning beam across said scanning field and any object in said scanning field, and generating a scan data signal representative of the detected laser light; (e) collecting a line of scan data over a sweep of the laser beam across the scanning field and any object therein, and buffering the collected line of scan data; and (f) decode processing said line of scan data collected and buffered in step (e) in an attempt to read any code symbol represented in said line of scan data, and when a code symbol is read within said line of scan data, then generating and transmitting symbol character data, corresponding to said decoded code symbol, to an intended destination. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification