JP2506121B2 - Optical memory card system - Google Patents

Description

The present invention relates to an optical memory card system, and more particularly to an optical memory card system suitable for reading a plurality of optical memory cards recorded at different recording densities.

[Conventional technology]

The conventional optical memory card is intended to have a constant recording density such that the recording density of the card does not vary depending on the type of the card, as described in JP-A-59-195327.

[Problems to be solved by the invention]

In the above-mentioned related art, when the recording density is different depending on the type of the optical memory card, no consideration is given to the point of reading the data, and the data can be correctly read only from the memory card storing the data at the constant recording density. There was a problem.

An object of the present invention is to provide an optical memory card system in which the card data can be reliably read by a card reader even if the recording density of the data portion of the memory card varies depending on the card as described above. There is.

[Means for solving problems]

An optical memory card system of the present invention includes an optical memory card having an information storage unit including a data unit, and a light source unit including a laser driving device for irradiating the optical memory card with a pulsed beam having a frequency corresponding to a frequency of an input clock. And a reading device that receives the pulsed beam reflected from the optical memory card, performs photoelectric conversion on the pulsed beam, and reads the content of the information storage unit of the optical memory card. It has the characteristics of

That is, the optical memory card includes a medium identification information section in which at least information of the recording density of the data section is recorded at a predetermined recording density prior to the data section in the information storage section, and the medium identification information section and A gap part is provided between the data parts, and the light source part outputs a clock having a frequency corresponding to the predetermined recording density to the laser driving device when reading the medium identification information part of the optical memory card, and While the pulsed beam is moving in the gap part, the frequency of the clock is changed to a frequency corresponding to the information of the recording density sent from the reading device to the light source part, and when reading the information storage part of the optical memory card. A clock circuit for outputting a clock having a frequency corresponding to the information of the recording density to the laser driving device, Based on the photoelectric conversion output of the reflected light from the medium identification information section of the Ricard, the recording density information is detected, and the recording density detection circuit for outputting the detected recording density information to the light source section is provided. Characterize.

[Action]

According to the present invention, since the medium identification information section provided prior to the data section is recorded with a predetermined recording density, the reading device is provided with a predetermined pulse shape corresponding to the predetermined recording density. The beam can reliably read the information of the recording density of the data section. Subsequently, the reading device switches the pulsed beam so as to match the read recording density so that the data recorded in the data part can be read, and thereby the data recorded in the data part is surely read. . The switching of the pulsed beam is performed while the pulsed beam is passing through the gap portion. As a result, even if the recording density of the data section differs depending on the optical memory card, the reading device can reliably read the data. Further, it is possible to provide an optical memory card capable of easily determining whether or not it can be read by the reading device.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings.

FIG. 2 is a diagram showing an example of an optical memory card to which the present invention is applied. As shown in the figure, the optical memory card 1 is provided with an information storage unit 2. FIG. 1 shows the information storage unit 2.
FIG. 4 is a diagram showing an example of the above, and is composed of a medium identification information section 3, a data section 4, and a gap section 5 between them, as shown. The medium identification information section 3 stores at least the recording density of the following data section 4. The data indicating the recording density of the medium identification information section 3 is stored at a constant recording density regardless of the recording density of the data section 4 so that the card reader can reliably read the data. The recording density of the data section 4 is constant for each card, but varies depending on the type of card, and there are a plurality of types.

FIG. 3 is a diagram showing an example of a reading device of the optical memory card 1. As shown, the reading device is an optical memory card 1.
Card moving means 6 for moving the optical card, a light source 7 for irradiating the information recording surface of the optical card with the pulsed beam 9, and a reflected light 10 of the pulsed beam 9 emitted from the light source 7 to the optical memory card 1 are detected. It is composed of a detector 8. When the optical memory card 1 is inserted into the reading device, the pulsed beam 9 is emitted from the light source 7 according to the recording density of the medium identification information section 3. The various optical memory cards 1 used here have the same recording density in the medium identification information section 3. Reflected light of the beam 9 applied to the optical memory card 1
The detector 8 reads the medium identification information part 3 stored in the head portion of the card by 10. In the medium identification information section, at least the recording density of the data section 4 of the optical memory card 1 is
It is remembered. Next, a pulsed beam 9 that coincides with the read recording density data is generated from the light source 7 and irradiated onto the information recording surface of the data section 4. The switching of the beam pulse is performed while moving the gap portion 5 between the medium identification information portion 3 and the data portion 4 of the optical memory card 1.
Further, the detector 8 can read the reflected light 10 according to the pulsed beam 9 to be emitted, and therefore, the reading can always be performed in accordance with the recording density of the data section.

FIG. 4 is a diagram showing a specific example of the light source 7 and the detector 8 shown in FIG. The light source 7 is a clock circuit as shown.
71, a laser drive circuit 72, and a laser section 73. The detector 8 includes a photodetector 81, an equalization circuit 82, and a recording density detection circuit 83.
It consists of and. The clock circuit 71 is a circuit that selects the frequency of the clock output 11 according to the recording density of the optical memory card 1 and outputs the selected clock signal according to the signal from the recording density detection circuit 83. First, when the optical memory card 1 is inserted, the clock output 11 for reading the information of the medium identification information section 3 is selected. An example of the clock output 11 is shown in FIG. The clock output 11 is applied to the laser drive circuit 72, and the output of the laser drive circuit 72 is applied to the laser section 73, whereby the electric signal is converted into the pulsed beam 9. Light reflected from optical memory card 1
10 enters the photodetector 81 and is converted into an electric signal. An example of the pulsed beam 9 and the reflected light 10 is shown in FIG.
It is shown in (c). The electric signal is input to the equivalent circuit 20 and shaped in waveform. The output signal 12 of the equivalent circuit 20 is input to the recording density detection circuit 83, and the recording density of the card data section is decoded. An example of the output signal 12 is shown in FIG.
The clock output 11 of the clock circuit 71 is changed according to the decoding result of the recording density. As a result, the data can be read in synchronization with the recording density of the data section 4 after the medium identification information section 3.

In the above embodiment, if a recording density that cannot be read by the reading device is recorded in the medium information identifying unit 3, the reading device should be configured so that it can be immediately determined that it is an unreadable optical memory card. You can

〔The invention's effect〕

According to the present invention, it is possible to provide an optical memory card system capable of surely reading the data recorded in the optical memory card even if the recording density of the data portion of the optical memory card is different for each card. Further, it is possible to provide an optical memory card system capable of easily discriminating whether or not it can be read by the reading device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of an information storage section of an optical memory card, FIG. 2 is an explanatory diagram showing an example of an optical memory card, and FIG.
FIG. 4 is an explanatory view showing an example of a reading device for an optical memory card, FIG. 4 is an explanatory view showing a concrete example of the light source and detector shown in FIG. 3, and FIGS. 5 (a), (b), (c), (D) is a waveform diagram for explaining the operation of the light source and the detector shown in FIG. 4. 1 ... Optical memory card, 2 ... Information storage section, 3 ... Medium identification information section, 4 ... Data section, 5 ... Gap section, 6 ...
... card moving means, 7 ... light source, 8 ... detector, 9 ...
Pulsed beam, 10 …… Reflected light, 11 …… Clock circuit,
72 ... laser drive circuit, 73 ... laser section, 81 ... photodetector, 82 ... equalization circuit, 83 ... recording density detection circuit.

Claims (1)

(57) [Claims] 1. An optical memory card having an information storage section including a data section, a light source section having a laser driving device for irradiating the optical memory card with a pulsed beam having a frequency corresponding to the frequency of an input clock, and The pulsed beam reflected from the optical memory card is received and photoelectrically converted,
In an optical memory card system including a reading device for reading the contents of the information storage section of the optical memory card, the optical memory card determines at least information about the recording density of the data section in advance of the data section in the information storage section. A medium identification information part recorded at a given recording density, and further a gap part between the medium identification information part and the data part, the light source part, when reading the medium identification information part of the optical memory card, A clock having a frequency corresponding to a predetermined recording density is output to the laser driving device, and the frequency of the clock is sent from the reading device to the light source unit while the pulsed beam is moving in the gap portion. Corresponding to the above recording density information when changing the frequency corresponding to the density information and reading the information storage section of the optical memory card A clock circuit for outputting a clock of a different frequency to the laser driving device, wherein the reading device detects the information of the recording density based on photoelectric conversion output of reflected light from the medium identification information part of the optical memory card, An optical memory card system comprising a recording density detection circuit for outputting information on the detected recording density to the light source section.