Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2001-04-02
2004-02-10
Le, Thien M. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S462340, C235S462010
Reexamination Certificate
active
06688527
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to bar code symbol reading systems and, more specifically, to systems having one or more base stations and one or more hand-held bar code symbol readers equipped to communicate with these base stations.
2. Brief Description of the Prior Art
Bar code symbols have become widely used in many commercial environments including point-of-sale (POS) stations in retail stores and supermarkets, inventory and document tracking, and diverse data control applications. To meet the growing demands of this technological innovation, bar code symbol readers of various types have been developed for scanning and decoding bar code symbol patterns, and for producing symbol character data to be used as input in automated data processing systems.
In general, prior art hand-held bar code symbol readers using laser scanning mechanisms can be classified into two major categories. The first category includes manually-actuated trigger-operated systems having lightweight laser scanners which can be held in a user's hand. The user positions the hand-held laser scanner at a specified distance from an object bearing a bar code symbol. Next, the user manually activates the scanner to initiate reading, and then moves the scanner over other objects bearing bar code symbols to be read. Prior art bar code symbol readers illustrative of this first category are disclosed in U.S. Pat. Nos. 4,387,297 to Swartz; 4,575,625 to Knowles; 4,845,349 to Cherry; 4,825,057 to Swartz, et al.; 4,903,848 to Knowles; 5,107,100 to Shepard, et al.; 5,080,456 to Katz, et al.; and 5,047,617 to Shepard, et al.
The second category of hand-held laser-based bar code symbol readers includes automatically actuated systems having lightweight triggerless hand-held laser scanners which can be supported in the hand of the user. The user positions the hand-held laser scanner at a specified distance from the object bearing the bar code, whereupon the presence of the object is automatically detected. The presence of the bar code symbol on the object is also detected, and thereafter the detected bar code symbol automatically read. Prior art illustrative of this second category of laser-based bar code symbol reading systems are disclosed in U.S. Pat. No. 4,639,606 to Boles, et al., and 4,933,538 to Heiman, et al.
Presently, there are basically two methods of interconnecting a hand-held laser-based bar code scanner to a base station which, depending on the particular application, may be either a controller, a keyboard-scanner interface device, or a central or host computer. The first method of interconnection employs physical wiring between each hand-held bar code scanner and an associated base unit. Typically, the physical wiring is realized as flexible cord having a coiled structure to permit elongation as required during bar code symbol reading operations.
A major drawback with bar code symbol reading systems using the physical-wiring method of interconnection is that the movement of the portable hand-held laser scanning device is restricted by the overall (extended) length of the flexible cord. In many applications, such as product inventory, the use of such bar code symbol reading systems is simply unacceptable. The second method of interconnection employs a “wireless” electromagnetic communication link between each hand-held bar code scanner (or reader) and its associated base unit. Typically, the electromagnetic communication link is established by transmitting and receiving electromagnetic signals over the radio-frequency (RF) or infra-red (IR) region of the electromagnetic spectrum. Examples of such systems are disclosed in U.S. Pat. Nos. 4,418,277 to Tremmel, et al. and 5,157,687 to Tymes, and in the U.S. Patents cited therein.
While prior art bar code symbol reading systems employing the wireless method of interconnection offer a marked degree of flexibility over systems utilizing the physical wiring method, such systems nevertheless suffer from a number of shortcomings and drawbacks. In particular, these systems require two-way packet communications which involves the use of complex data communications protocols and a separate transmitter and a receiver (i.e., transceiver) at each hand-held bar code symbol reader and base unit in the system. Typically, these data communications requirements increase the cost of manufacture of such systems, and substantially increase the electrical power consumed by each hand-held bar code symbol reader.
Thus, there is a great need for a bar code symbol reading system and method which overcomes the above-described shortcomings and drawbacks without compromising system performance and versatility.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the present invention to provide a bar code symbol reading system having at least one hand-supportable bar code symbol reading device which, after successfully reading a code symbol, automatically constructs and then transmits a data packet to a base unit positioned within the data transmission range of the bar code symbol reading device.
It is another primary object of the invention to provide a bar code symbol reading system which, upon successful receipt of the transmitted data packet and recovery of symbol character data therefrom, employs a base unit that generates an acoustical acknowledgment signal. This acknowledgment signal is perceptible to a user of the bar code symbol reading device who is located within the data transmission range thereof.
A further object of the present invention is to provide such a system with one or more automatic (i.e., triggerless) hand-supportable laser-based bar code symbol reading devices, each of which is capable of automatically transmitting data packets to its base unit after successfully reading a bar code symbol.
A further object of the present invention is to provide such a bar code symbol reading system in which the hand-supportable bar code symbol reading device can be used as a portable hand-supported laser scanner in an automatic hands-on mode of operation, or as a stationary laser projection scanner in an automatic hands-free mode of operation.
A further object of the present invention is to provide such a bar code symbol system, in which the base unit is adapted to mechanically support the hand-supportable bar code symbol reading device in its automatic hands-free mode of operation.
A further object of the present invention is to provide such a bar code symbol system in which the base unit contains a battery recharging device that automatically recharges batteries contained in the hand-supportable device when the hand-supportable device is supported within the base unit.
It is another object of the present invention to provide such an automatic bar code symbol reading system with a mode of operation that permits the user to automatically read one or more bar code symbols on one or more objects in a consecutive manner.
A further object of the present invention is to provide such an automatic bar code symbol reading system, in which a plurality of automatic hand-supportable bar code symbol reading devices are used in conjunction with a plurality of base units, each of which is mated to a particular bar code symbol reading device.
A further object of the present invention is to provide such an automatic bar code symbol reading system, in which radio frequency (RF) carrier signals of the same frequency are used by each hand-supportable bar code symbol reading device to transmit data packets to respective base units.
A further object of the present invention is to provide such an automatic bar code symbol reading system, in which a novel data packet transmission and reception scheme is used to minimize the occurrence of data packet interference at each base unit during data packet reception.
A further object of the present invention is to provide such an automatic bar code symbol reading system, in which the novel data packet transmission and reception scheme enables each base unit to distinguish
Colavito Stephen J.
Germaine Gennady
Knowles Carl H.
Rockstein George B.
Wilz, Sr. David M.
Le Thien M.
Metrologic Instruments Inc.
Morgan & Lewis & Bockius, LLP
Sanders Allyson N.
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