JPS6299963A - Optical-card reader - Google Patents

Abstract

PURPOSE:To improve the reliability of an optical-card reader, by detecting the number of reading errors and, when the detected number exceeds a correctable range, performing the process of an effect that reading of an optical card is impossible. CONSTITUTION:Reading signals of 1-block 31-bits read from an optical card C are inputted to an Ex-OR 6 through waveform shaping circuits 4 and 5, respectively, and the output signal of the waveform shaping circuit 5 is inputted to an error correcting circuit 7 and frequency divider 8. The number of error detecting signals is counted by a counter 11 and the divider 8 actuates a comparator 10 when the quantity of 31 bits is read. The comparator 10 compares the count value of the counter 11 with a permissible error number set in a setter 9. When the number of errors is >= three, a signal is outputted from the comparator 10 and a buffer 14 sends operation start commands to a card return and recovery controller 12 and card use disallowable alarm controller 13. Then the optical card C is returned to an inserting port 16a or recovered and it is indicated that use of the card is disallowable through a display device 17.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention Optical cards are very sensitive to scratches. Conventional card reading devices have a function of making some corrections and outputting read data even if there is a reading error, and it is unclear whether the outputted read data is correct. According to this invention, the amount (number) of reading errors is detected, and when the amount of errors exceeds a correctable range, processing is performed to indicate that the optical card cannot be read, thereby increasing the reliability of the optical card. There is.

[Technical Field] The present invention relates to a reading device for a so-called optical card, in which predetermined data is recorded on a card-shaped record carrier in an optically readable state.

[Prior Art] FIG. 2 shows an example of the configuration of a conventional optical card reading device.

A light irradiation or projection optical system 1 illuminates the light source C. The reflected light from the optical card C enters two light receiving or light detecting optical systems 2 and 3. Predetermined data is recorded on the optical card C by forming so-called pits (indentations or recesses). The intensity of the reflected light from such bits varies depending on the location. Therefore, by changing the focal position, reading angle, etc. of the photodetection optical system.

The optical system can read the state in which the presence or absence of reflection is reversed. The optical systems 2 and 3 have different focal positions, angles, etc., and the high level and low level of their read signals are inverted. Konera's 1-read Shingetsu passes through waveform shaping circuits 4 and 5, respectively, and is then subjected to exclusive OR (E
x-OR, exclusive logic circuit) 6.

If the surface of the card C is normal, the outputs of the waveform shaping circuits 4 and 5 are always inverted to high 1 novel and low 1 novel, so the output of Ex-OR 6 is at a high level. If there are scratches, dirt, or other defects on the surface of the card C, the output signals of the single waveform shaping circuits 4 and 5 will be at the same level.

Therefore, the output of Ex-OR6 becomes a row 1 novel. This is the error detection signal, and this signal is input to the error correction circuit 7. The read signal from one waveform shaping circuit 5 is also input to the error correction circuit 7. This correction circuit 7 performs error detection and correction based on No. n when an error detection signal is input. It performs an operation to correct the error by Q'T and outputs the result as a data signal.

However, errors are not always corrected accurately by the correction circuit 7. If the number of errors exceeds the ability of the error detection and correction code, the errors will not be corrected correctly and an erroneous signal will be output as a data signal. Since the correction circuit 7 always outputs some kind of signal as a data signal regardless of whether the data is correct or incorrect, its reliability is not necessarily high.

[Object of the Invention] An object of the invention is to improve the reliability of an optical card reader.

[Configuration and Effects of the Invention] The optical card reading device according to the present invention includes a means for reading data recorded on an optical card, a means for detecting reading errors in 1-bit units, a means for accumulating the number of detected errors, and a permissible number of errors. means for setting a maximum number of errors allowed, means for comparing the accumulated number of errors with the set maximum number of errors allowed, and means for generating an output signal to address the optical card depending on the comparison result. It is characterized by

Generally, data is recorded on an optical card in units of a predetermined unit length (block). In such a case, the comparison in the comparison means is performed for each data block of the optical card data, and the output signal generation means selects a block in which the number of accumulated errors is greater than the maximum allowable number of errors. Preferably, it is arranged to count a number and generate an output signal in response to this number.

The output signal generating means generates at least one of a card return command, a card collection command, and a card unreadable warning command when the number of accumulated errors is greater than the maximum allowable number of errors, and the optical card is Disable.

According to this invention, a defective optical card with a large amount of errors is invalidated by some method as described above. therefore.

The reliability of optical card reading is high because the read data signal of a defective optical card is never output, and if a data signal is output, it can be assumed to be completely correct unless there is an error in the two-circuit transmission. increases dramatically.

[Description of Embodiment] FIG. 1 shows an embodiment of the present invention. Components that are the same as those in the conventional example shown in FIG. 2 are designated by the same reference numerals, and their explanations will be omitted.

The error detection signal output from Ex-OR6 is input to the counter 11 and accumulated there. On the other hand, the output signal of the waveform shaping circuit 5 is sent to the error correction circuit 7 and input to the frequency divider 8.

The frequency division ratio in the frequency divider 8 varies depending on the ability of the error detection and correction code. Although not limited to a specific error detection and correction code, for example, a BCH (31, 21> code will be explained. 3 in BCH (31, 21)
1 indicates the code length, and 21 indicates the number of information symbols.

This code has the ability to correct errors in any two bits out of the 31 bits in one block. When such an error detection and correction code is used, the 9 frequency divider 8 is 1
A /31 divider is used. It is assumed that the frequency dividing operation in the frequency divider 8 is synchronized with the data block on the optical card C. In addition, it is possible to correct errors up to 2 bits, so
Two bits are preset in the allowable error number setter 9 as the maximum number of allowable errors.

The read signal of 1 block of 31 bits read while the destination card C inserted into the optical card insertion slot lea provided in the panel 16 is transported by the card transport mechanism 15 is waveform-shaped and then Circuit 6. The signal is input to an error correction circuit 7 and a frequency divider 8, respectively. A counter 11 counts the number of data (number of error detection signals) determined to be an error due to factors such as scratches on the optical card. The frequency divider 8 acts on the comparator 10 to activate the comparator 10 when 31 bits are read. The comparator IO compares the number of allowable errors set in the setting device 9 with the count value of the counter 11. If the number of errors (ie, the count value of the counter 11) is 2 or less, no output is generated from the comparator 10. If there is an error, the correction circuit 7 corrects the error and outputs a data signal. After the comparison operation by the comparator IO, the counter 11 is cleared by a reset signal output from the 1 frequency divider 8. After this, the primary data is read, and the above operation is repeated.

When the number of errors (the count value of the counter 11) is 3 or more, the comparator 10 outputs, for example, one pulse or a signal at a constant level, and inputs it to the buffer 14. Buffer 14 stores this input signal.

The buffer 14 has different performance depending on the accuracy required for the data. For example, if you need high-precision data,
If it is inconvenient that there is even one block of uncorrectable data, the buffer 14 sends the input pulse as it is to the card return or collection control device 12 and card unusable warning control device 13 as an operation start command. The transport mechanism 15 is driven by the control device 12, and the optical card C is returned to the insertion slot 16a as shown by arrow A or collected as shown by arrow B. In addition, the control device 13
As a result, the display 17 provided on the panel 16 displays that the card cannot be used.

As mentioned above, if there is an uncorrectable error in even one block, a message to that effect is displayed or the card is returned or collected, the data signal output from the error correction circuit 7 is transmitted through two circuits. As long as there are no errors, it is completely correct and extremely reliable.

On the other hand, some data, such as image data, can tolerate some errors. In this case, the input signal from the comparator 10 is held in the buffer 14, and when the input signal exceeds a certain number or level, the control device 12.13 is activated. This allows relatively high reliability and smooth reading.

Note that it is sufficient to have either one of the control devices 12 and 13. The warning indicator 17 is not visually visible, but may be an audible buzzer or the like. Alternatively, the optical card C itself could be returned with a stamp indicating that it is unusable.

[Brief explanation of drawings]

FIG. 1 is a block and configuration diagram showing an embodiment of the present invention. FIG. 2 shows a conventional example. 2.3...Photodetection optical system. 6...Ex-OR for error detection. 7...Error correction circuit. 9... Allowable error number setter, 10... Comparator. 11...Counter. 12...Card return 1 collection control device. 13...Card unusable warning control device. 14...Buffer. Patent applicant: Tateishi Electric Co., Ltd. Agent: Nobuaki Ushiku (1 other person) Figure 2

Claims (4)

[Claims] (1) Means for reading data recorded on an optical card. Means for detecting read errors in 1-bit units and means for accumulating the number of detected errors. means for setting a maximum number of tolerable errors; means for comparing the accumulated number of errors with the set maximum number of tolerable errors; and means for generating an output signal for addressing the optical card in response to a result of the comparison; An optical card reader equipped with (2) The optical card reading device according to claim (1), wherein the comparison by the comparing means is performed for each data block of optical card data. (3) the comparison means performs the comparison for each data block of the optical card data, and the output signal generation means counts the number of blocks in which the number of accumulated errors is greater than the maximum allowable number of errors; The optical card reading device according to claim 1, which generates an output signal in accordance with this number. (4) The optical card according to claim (1), wherein the output signal generating means generates at least one of a card return command, a card collection command, and a card unreadable warning command. reader.