METHOD OF RECORDING DATA ONTO AN OPTICAL DATA RECORDING CARD

Abstract: A concrete data format to achieve the following assign­ ments, i.e., (1) to control the reading operation of a line sensor for a unit read column, (2) to maintain synchronism with data bits during the reading operation, (3) to dis­ criminate neighbouring unit read columns, (4) to cope with the generation of errors during the reading operation, and (5) to efficiently access the data. To achieve the above assign­ ments, the data bits are arranged in the form of unit read columns, bars are provided to guide the line sensor, and a format is formed to instruct a central position of the unit read columns. Further, special bars are provided to correct the in­ clination of the line sensor. The data bits are arranged at pre­ determined periods, and synchronizing bits are provided to maintain synchronism with the period of data bits during the reading operation. There are further provided discimination bits to discriminate the neighboring unit read columns during the reading operation. The discrimination bits may be so arranged that columns of even numbers and columns of odd numbers are discriminated from each other. Besides, the dis­ crimination bits may be composed of three bits to increase the reliability. The format of this invention has particular error check bit(s) to cope with errors that may develop during the reading operation. Further, the data are recorded in a dis­ persed manner to cope with errors such as local smudges, and others. To efficiently access the data, necessary data such as predetermined addresses are recorded together with general data. The invention further discloses a method of forming bits by modulating digital signals, and an optical system and a signal processing system of a reader for the optical data recording card. The optical data recorded in by the method of the invention is expected to find extensive app­ lications as a recording medium for computer programs, video and music data, and a variety of data bases.

Description: TECHNICAL FIELD The present invention relates to a method for recording data onto optical recording cards and more particularly a method for recording data onto data cards in the form of pits by optical means. BACKGROUND ART At present, magnetic cards such as cash cards, credit cards and the like have been widely used, but recently there has been proposed an optical data recording card upon which is optically recorded information in order to improve recording density and to ensure reliable data storage. For instance, PCT/US 84/01463 (International Publication on April 25, 1985: International Publication No. W085/01818) discloses a technique developed by DREXLER TECHNOLOGY CORPORATION in USA concerned with optical data recording cards. However, in order to accurately read out stored data and to efficiently access data, data must be recorded based upon a predetermined format. In order to attain an optimum format, there still exist various problems which must be solved and so far there has not been proposed a practical optimum method for recording data onto optical data recording cards. Especially in order to ensure the readout of data and the efficient access to data, the following practical problems constitute a barrier: (Problem 1: control of a line sensor for reading out a unit readout array) A line sensor reads out the data recorded in the form of pits from respective unit readout arrays and in order to properly shift the line sensor to a predetermined position for reading out the data stored in a specified unit readout array, a suitable data recording format must be devised. Especially, the control must be carried out accurately so that the direction of rows of the unit readout arrays must coincide with the direction of the sensor array of the line sensor with a high degree of accuracy. (Problem 2: synchronization with data pits) The data pits are recorded and spaced apart from each other by a predetermined distance. In case of reading out such data pits by the line sensor, the readout timing must be in synchronism with the distance between the pits. Therefore, a data recording format must be provided with a means for attaining such synchronization. (Problem 3: discrimination between the adjacent unit readout arrays) The line sensor reads out the data pits in respective unit readout arrays in the manner described above and when the data from one unit readout array is read out, the operation for reading out the data stored in the next unit readout array is executed. In this manner, a plurality of unit readout arrays are read out sequentially, but in case of scanning the line sensor, it must be detected that the operation for reading out the next readout array has been started. That is, a data recording format bearing the information capable of distinguishing between the adjacent unit readout arrays must be devised. (Problem 4: countermeasures against readout errors) In general, since individual person carries and uses the optical data recording cards, the data recording surfaces tend to be contaminated. Optical reading systems are very sensitive to such surface contamination, resulting in readout errors. It follows therefore that there must be devised a data recording format capable of avoiding such readout errors. (Problem 5: efficient access to data) As described above, since the optical data cards are carried by individual persons, their dimensions or sizes must be so selected that they may be put into pockets. Meanwhile, various data must be recorded in a limited space, therefore a data recording format capable of permitting the easy access to the stored data must be devised. DISCLOSURE OF THE INVENTION In view of the above, the primary object of the present invention is to provide a method for recording data on optical data recording cards in such a way that the stored data can be positively read out and the efficient access to the specified data can be ensured. In addition, the present invention was made to attain the positive control of the readout operation by a line sensor for reading out the data stored in individual unit readout arrays. The feature of the present invention as defined in appended claim 1 resides in the fact that a pit representative of a center line position of a data row is added to one end of the data row and a bar representing the boundary between the data rows is provided adjacent to one end of a data row, whereby the operation of a line sensor for reading respective unit readout arrays can be positively controlled. FIGS. 1(a) and (b) are schematic views of optical data recording cards onto which are stored the data by a method in accordance with the present invention; FIG. 2 is a fragmentary view, on an enlarged scale, of the optical data recording card shown in FIG. 1(a) and illustrating a recording format thereof; FIG. 3 is a view used to explain a recording method in accordance with the present invention which permits the control of the read operation for reading a unit readout array; BEST MODES FOR CARRYING OUT THE INVENTION 〈General Description of Formats〉 Now the present invention will be described in detail with reference to the best embodiments shown in the accompanying drawings. FIG. 1 is a view of an optical data recording card on which the data are stored by a first embodiment of the present invention. A data recording portion 2 is defined on the surface of a recording card 1 and a plurality of data recording regions 3 are defined in the form of stripes in the data recording portion 2. In FIG. 1(a), the data recording regions 3 are extended vertically while in FIG. 1(b) they are extended horizontally. Data are optically recorded in and read out from respective data recording regions 3. In case of readout, a CCD line sensor or the like is generally used as a read head and is caused to scan each data recording region 3. For instance, in case of the card as shown in FIG. 1(a), the read head scans vertically each data recording region 3 and in case of the card as shown in FIG. 1(b), the read head scans horizontally each data recording region 3. Therefore, when the read head is inclined during the scanning step, the stored data cannot be read out accurately. Especially, the recording density of the optical data recording card is higher than that of the magnetic card so that in order to read out the stored data accurately, the read head inclination must be controlled with a high degree of accuracy. FIG. 2 is a fragmentary view, on an enlarged scale, of the data recording regions 3 of the recording card shown in FIG. 1(a). A read control format region P (shown as consisting of two bars Z) is defined on the left side portion of each data recording region 3. The data used for controlling the read head is recorded in a predetermined format in the region P. In the read head, read elements are arranged in a horizontal array as indicated by the one-dot chain lines 4 and the read head 4 scans vertically from the upper end to the lower end of each data recording region 3 so that the stored data are read out from the data recording regions 3 which are spaced apart from each other in the horizontal direction. In practice, the data to be read out are recorded in the form of pit trains in a region Q. In this embodiment, the region Q is further divided into five sub-regions A, B, C, B' and A'. Address data indicating an address of each data recording region are recorded in the sub-regions A and A'; auxiliary marks for correcting the inclination of the read head 4 are stored in the sub-regions B and B'; and an essential data are recorded in the sub-region C (partly shown in FIG. 2). The read head 4 has a plurality of read elements arranged one-dimensionally in an array in the X direction in FIG. 2. Data are recorded in the form of pits in the sub-region C. The pits are elongated in the Y direction (and are ℓ in length) and one array of pits arranged in the X direction is referred to as "a unit readout array". A plurality of unit readout arrays are arranged in the Y direction. The read head 4 reads pits in each unit array at one time. Therefore, when the read head 4 is caused to be deviated from the X direction and inclined as pointed out in the above-described problem, it reads out the pits in two arrays when the inclination of the read head 4 exceeds a predetermined degree so that it becomes impossible to read out the stored data accurately. The data formats recorded on the respective regions will be described in detail hereinafter and the data recorded in the region P are used to solve the above-described problems 1, 2 and 3; the data stored in the regions A and A' are used to solve the above-described problem 5; and the data stored in the region B and B' are used to solve the above-described problem 1; and the data are recorded in the region C in a format capable of solving the above-described problem 4. 〈Recording method for controlling the read operation by a line sensor for reading each unit readout array〉 EMBODIMENT FIG. 3 shows another recording method which permits the control of a line sensor for reading a unit readout array and is a view of the region C, on an enlarged scale, of Fig. 2. For the sake of explanation, only one unit readout array is shown. A unit readout array 5 comprises a leading pit P₀ and data pits P₁-P n whose centers are on a center line CL and which are spaced apart from each other by a predetermined distance. The leading pit P₀ is used to indicate the position of the center line CL and its length in the direction perpendicular to the center line CL which is called a pit length is considerably shorter than those of the data pits P₁-P n . The data pits P₁-P n have a long pit length so that their existence can be positively detected by the line sensor. Since the leading pit P₀ and the data pits P₁-P n are arranged in the manner described above, when the line sensor (not shown) detects the leading pit P₀, it can also detect the data pits P₁-P n . In general, the relative angular relationship between the line sensor and a card is such that the line sensor is slightly deviated from the center line CL. Therefore even when the angle of the card in relation to the line sensor is relatively great, there is no fear that the line sensor fails to detect the data pits P₁-P n and especially the last pit P n . The unit readout array 5 arranged in the manner described above is interposed between bars Z and Z' which function as guides in case of scanning by the line sensor as described above, represent the side boundaries of the unit readout array 5 and are continuously extended in the direction perpendicular to the center line CL of the unit readout array. So far it has been described that the pit P₀ representative of the position of the center line CL is positioned at the leading end of the unit readout array 5, but it is understood that it may located at the trailing end thereof. In short, it suffices that even when the direction of the unit readout array 5 and the scanning direction of the line sensor 4 are deviated from each other by a small angle, the line sensor can detect all the pits P. The bars Z and Z' not only guide the line sensor 4 but also represent the side boundaries of the unit readout array 5 so that they may be discontinuous and that only one bar may be provided for a plurality of unit readout arrays. As described above, according to the embodiment 2, the pit representative of the position of the center line of a data train is located at either end thereof and the bars are extended adjacent to the ends of the data trains to define the boundary lines between the data trains so that the scanning direction of the line sensor can be accurately aligned with the direction of each data train and that the arrangement of each data train can be distinguished with a high degree of accuracy. In case of the optical recording card shown in FIG. 1(a), when the reference data is stored at the upper portion of each data storage region 3, the readout operation can be accomplished at the optimum readout positions for respective data storage regions even when the pit period varies from one data storage region to another due to the deflection of the card or the distortions of the optical system. Another selection method is such that the data concerning to the picture elements to be selected are previously registered on a recording medium to be read out. In case of optical recording cards made of the same material and having the same pattern, it may be considered that they have a common feature with regard to the data pit positions. It follows therefore that when the picture elements to be selected in case of readout of optical recording cards having some common features are previously registered, the selection can be made even when no reference data are recorded in each optical recording card. According to the readout method described above, prior to the readout operation, there is established one-to-one correspondence between the position of each data pit and a picture element of the reading line sensor so that the data pit is read out by the corresponding picture element so that all the data pits can be read out at the optimum readout positions. INDUSTRIAL APPLICABILITY In order to suggest the industrial applicability of the optical data recording cards in accordance with the present invention, some of their applications will be described. However, the applications to be described above are only typical examples and it is to be understood that they may be applied in various fields in various manners. (1) Uses of recording media of computer programs: At present, magnetic disks and a floppy disks have been widely used as recording media for storage of the computer programs. Furthermore, IC cards have been devised and demonstrated recently. However, it should be noted that the optical data storage cards have a data-packaging density about 25,000 times as high as that of the magnetic cards and about 250 times as high as that of the IC cards (at present, the capacity of each card is about 400 K bits) so that the optical data recording cards may be considered to be the recording media capable of attaining the highest data-packaging density. In addition, unlike the magnetic recording media whose stored data are destroyed by the electromagnetic phenomena, the optical data recording cards have not such defects. Furthermore, when compared with the IC cards, the optical data recording cards have the advantage that their functions will not be adversely affected at all even they are folded or due to the electrostatic effects. Moreover, they are convenient to be carried out and the possibility that the optical data recording cards are used as recording media for personal computers and the like is very high. (2) Uses as media for recording images: As described above, the optical data recording cards has an extremely high data-packaging density, they are best suited for used as recording media for recording image or pattern information. It is possible to store all image or pattern information such as picture books, design drafts, maps and so on. Furthermore, they can advantageously applied to the videotech systems which have been recently developed and come into wide use. (3) Uses as media for storage of various data base: The optical data recording cards are best suited to be used as media for recording data base. For instance, they may be used as media for storage of all information such as commercial catalogs distributed in exhibitions or fairs, data concerning stock prices and bonds, publication catalogs, data concerning periodicals, judicial precedents and so on. (4) Uses as media for storage of musical data: When a music is recorded on an optical data recording card, the latter can be used as a music medium instead of cassette tapes and compact disks which are widely used at present. Since information is optically and digitally recorded, the recorded music can be reproduced with a high degree of quality. Furthermore, in case of the reproduction of music, its test, composer and other addition information can be displayed on a display device. When audio data are recorded instead of music, it becomes possible to use them as a data base. (5) Other personal uses: 1. Telephone guides: The optical data recording cards may be used as telephone guides in which desired telephone numbers in in-company private automatic branch exchange systems, telephone numbers of restaurants and so on. Especially, in case of an in-company telephone exchange system, when the telephone sets and an computer are interconnected with each other, the telephone guide can realize the automatic dialing system into which is inserted an optical data recording card. 2. Dictionaries: At present, the data storage capacity of each optical data recording card is about 400 K bytes, but it may be used as a dictionary of a foreign language studied at the level of a junior high school. 3. Cooking cards: It is possible to record the data concerning materials and cooking methods of respective menues on an optical data recording card. When not only the word data but also the audio data, the optical data recording cards become more effective in use. In addition, an automatic cooking system can be realized when the optical data recording cards are combined with an electronic range incorporating therein a microcomputer. 4. Golf course guides: Various guide data for each of 18 holes in a golf course are stored on the optical data recording cards and the cards are distributed to the golf players in golf club houses, Then, while the players are waiting for their turn, they can study their golf playing plans referring to the guide data. 5. Navigator maps for automobiles: The drivers can use within their cars the optical data recording cards on which are recorded the data such as road maps and so on. when a readout or reproduction device is disposed in a dash-board and when a driver inserts a card into it, a desired map may be displayed. 6. The optical data recording cards may be used as cards on which are recorded authentic records of celebrated chess or go games. A user may buy a chess or go record guide of a celebrated chess or go game that he/she prefers and inserts it into a readout or reproduction device so that the chess or go record may be reproduced on a display device. Furthermore, the optical data recording cards recording a chess or go training program may be put on the market. 7. Correspondence course cards: It is possible to record various instruction data in correspondence courses such as various data concerning gardening (such as seeding, transplantation, pruning and so on) on the optical data recording cards to be sent every month to specific users. Since the optical data recording cards can withstand against folding and will not be adversely influenced by the magnetic effects, they are particularly suitable for mailing.

Claims: A data recording method for recording data on an optical data recording card as a plurality of parallel data arrays (5) characterized in that a pit (P₀) for indicating the center line (CL) position of a data array (P₁-P n ) is added at either end of said data array and bars (Z) which serve as a guide in case of reading the data arrays are extended in a direction transverse to the center line direction of said data arrays in the vicinity of one ends of said data arrays. A data recording method as set forth in Claim 1 further characterized in that the length of said pit (P₀) indicating the center line position is shorter than those of pits (P₁-P n ) constituting each data array. A data recording method as set forth in Claim 2, wherein said pit (P₀) indicating the center line position is a circular pit whose center coincides with said center line (CL).

Inventors: KURAMOCHI WATARU, SAKAI YORIHIKO, TSURUOKA YOSHIAKI, KURAMOCHI, WATARU, SAKAI, YORIHIKO, TSURUOKA, YOSHIAKI
Applicants: DAINIPPON PRINTING CO LTD, DAI NIPPON INSATSU KABUSHIKI KAISHA
Application year: 1986
Main classification: G11B7
IPC codes: G06K7, G11B20, G11B7, G11B27, G06K19