Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
1999-10-12
2002-01-15
Lee, Michael G. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S454000, C235S462090
Reexamination Certificate
active
06338433
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of laser writing multiple updatable 2-D bar codes on optical memory cards and labels which are readable with a photo-detector array such as a CCD array.
BACKGROUND ART
The commercial fields for linear optical data storage include optical memory cards, two-dimensional bar codes, and digital sound on motion picture films.
The PDF-417 (Portable Data File), two-dimensional bar code has become a widely accepted way of storing data on cards, documents, and packages. It is used to encode graphics, including fingerprints. It has begun to be used as a form of postage stamp printed by a laser printer connected to a personal computer following authorization over the Internet. The PDF-417 specification was disclosed in 1991. PDF-417 utilizes images with minimum dimensions of about 150 microns. An earlier, higher resolution form of two-dimensional bar code was disclosed in U.S. Pat. No. 4,634,850 entitled, “Quad Density Optical Data Systems,” assigned to Drexler Technology Corporation, which was filed Nov. 4, 1985, and issued Jan. 6, 1987. A closely related patent is U.S. Pat. No. 4,786,792 issued Nov. 22, 1988, which is also assigned to Drexler Technology Corporation. These two patents relate to reading a high-resolution form of two-dimensional bar codes with image dimensions of 3 to 35 microns compared with the 150-micron image dimension of PDF-417. Examples of patents directly related to the PDF-417 system are U.S. Pat. Nos. 5,243,655, 5,304,786, and 5,319,181 filed from 1990 to 1992 and issued 1993 and 1994, which are assigned to Symbol Technologies Inc.
Other 2-D bar code products, in addition to PDF-417, include Aztec, Code 16K and Code 49. When PDF-417 is referred to in this application, it is meant when applicable, to include other 2-D bar code products as well. A nine-page article entitled “Fundamentals of Scanning New 2-D Codes with CCD Area Imagers”, has been published by Auto Image ID, Inc. of Cherry Hill, N.J., 08003.
Three patents have been assigned to Drexler Technology Corporation which involve the laser recording on reflective optical data storage medium using a microscopic laser beam of one to a few microns in diameter to create eye-visible images formed from pixels (picture elements), which in turn are formed from groups of 4, 9, or 16 closely-spaced laser-recorded microscopic spots. These pixels are used to create visual alpha-numeric characters or images, including portrait images of people. The three Drexler Technology patents are U.S. Pat. No. 4,680,459 entitled, “Updatable Micrographic Pocket Data Card,” U.S. Pat. No. 4,814,594 entitled, “Updatable Micrographic Pocket Data Card,” and U.S. Pat. No. 5,421,619 entitled, “Laser Imaged Identification Card.”
Methods and apparatus involving linear optical data storage of data on motion picture film are described in the following seven U.S. patents. In these cases the digital optical data represents motion picture digital sound. Two of those patents, assigned to Drexler Technology, are U.S. Pat. Nos. 4,503,135 and 4,603,099. Patents assigned to Sony Corporation in this field include U.S. Pat. Nos. 5,471,263, 5,523,996, 5,543,868, and 5,666,185. One of the relevant motion picture sound patents assigned to Dolby Laboratories is U.S. Pat. No. 5,710,752.
Another relevant patent is recently-issued U.S. Pat. No. 5,932,865 assigned to Drexler Technology Corporation, which is entitled, “Anti-Counterfeit Validation Method for Electronic Cash Cards Employing an Optical Memory Stripe.” Two sentences in the abstract point out the relevant features of this patent; namely, “Such counterfeiting can be inhibited by bonding an optical memory stripe to the smart card with pre-recorded or post-recorded validation data on the card. This optical validation data would be read with a photodetector array and could be transmitted to the recipient during funds transfer and/or used locally to control dispensing of cash.” This patent explains the importance of laser recording data which are readable with CCD arrays, but does not disclose the method of the present invention.
Typical optical memory cards utilize a 35 mm or 16 mm wide, reflective optical memory recording stripe which stores about one to four megabytes of data when 2.5 micron spots and 12 micron track-to-track spacings are used. The reader/writer device sells for about $2,500, and read-only devices for those cards are also expensive because of the precision required to track the digital data on the optical card with a low power laser diode. Customers have requested an inexpensive, read-only device for the optical memory cards, and it is believed some customers would probably accept a somewhat lower data-storage-capacity card if that would lead to an inexpensive read-only device.
It is the object of the present invention to devise a method and apparatus for laser recording of a single or multiple two-dimensional bar code(s) readable with CCD or other photodetector arrays and with data storage capacities ranging from about 15 to more than 500 times greater than that of PDF-417 bar codes. Another object is to utilize data-pixel-based two-dimensional bar codes on cards or labels for authentication, validation, authorization, or identification involving Internet and Intranet E-Commerce transactions, documents, communications, and manufactured products. Another object of the invention is to devise a method and apparatus to make CCD-read data-pixel-based two-dimensional bar codes updatable. Another object is for an optical memory card to be utilized in reading and writing microscopic data spots that can be grouped into large data pixels to form single dimension bar codes known as 1-D bar codes. The 1-D bar code product types include Code 39, Code 93, Code 128, Code 11, Code B, Coda Bar, EAN, UPC, MSI, PostNet, Royal Mail (RM 45CC), and Telepen.
DISCLOSURE OF THE INVENTION
The above objectives have been met by a pre-formatted, laser-recordable optical memory stripe or patch being bonded to a plastic card, or to a label medium coated with an adhesive. The laser recording material should be of the DRAW (direct-read-after-writing) type where laser data is instantly recorded without a post processing operation. The pre-formatted data tracks on the optical memory stripe or patch would be separated by a distance of about 5 microns to 40 microns and preferably, to accommodate existing commercial equipment such spacing should be about 12 microns, which represents an ISO standard for optical memory cards. The 12 micron spacing would include a linear edge region 2 microns wide and a linear recordable region 10 microns and thus an edge-to-edge spacing of 12 microns.
The laser-recorded microscopic data spots are defined as in the range of between 0.6 microns to 3 microns in diameter but more typically for optical memory cards at about 2.5 microns in diameter. The number of microscopic data spots that could fit across a track width could be as small as two and as many as seventy, with about two to six being preferred.
Whereas read-only devices utilizing laser tracking of pre-formatted tracks are expensive, a read-only device using a linear CCD array to read multiple tracks encompassing large data pixels can be inexpensive under the right design conditions. To minimize data errors, at least two or three photosensitive detectors of the photodetector array should read each data pixel. The use of 7- to 10-micron size data spots with a CCD array would work technically but might not lead to the lowest price read-only device today, owing to the cost of the required CCD array. CCD arrays become lower in cost when the size of the data spots being read are greater than 10 microns, but data storage capacity of an optical memory card is reduced for larger data spots by the square of the data spot size. If the data pixels are used to form miniature versions of standard one-dimensional or two-dimensional bar codes are large enough they can be scanned and read with a laser beam and one or more single photodetector(s).
The objects of the invention are achieved by cre
Drexler Technology Corporation
Lee Michael G.
Schneck Thomas
Taylor Larry D
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