JPH02141932A - Optical information reproducing device - Google Patents

Abstract

PURPOSE:To demodulate desired information at a desired time by storing at least a part of information on plural storage areas when plural storage areas on a recording medium are irradiated with light to reproduce the information. CONSTITUTION:The light obtained by irradiating a track (n) is inputted to a selector 34 via a photoelectric conversion detection element 31, an amplifier 32 and a binarization circuit 33. An output from the selector 34 selected by a selecting signal 34a is given to a data demodulator 37 via a PLL circuit composed of a phase comparator 35 and a VFO 35 and the demodulation signal of the track (n) is obtained. On the other hand, the light obtained by irradiating a track (n+1) is inputted to a memory 44 and stored therein via a detector 31, an amplifier 42 and a binarization circuit 43 similarly. The stored data is read via the selector 34 and the result is obtained as the demodulation signal of track (n+1) via the phase comparator 35, the VFO circuit 36 and the data demodulation circuit 37.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a case where a plurality of recording areas on a recording medium are simultaneously scanned as a reproducing means in a device that reproduces information recorded on a recording medium using light. This invention relates to means for reproducing information.

[Conventional technology]

When reproducing information from a recording medium that records or reproduces information using light, such as an optical disk or optical card, there is a method in which a single track is irradiated with a single light emitted from an optical head and scanned. generally known. However, in this method, the light scans the track according to the relative speed of the optical head and the recording medium. Then, the optical information obtained by reflection or transmission from the recording medium is sequentially converted into electrical signals to obtain information. Therefore, the information read speed is determined by the relative speed between the optical head and the recording medium, and cannot be made any faster.

Therefore, in U.S. FAT No. 4730293,
? A technique for simultaneously irradiating a number of tracks with light has been shown. The document also states that the readout speed can be quadrupled by simultaneously irradiating light onto a plurality of tracks and reading out the tracks.

However, this U, S, FAT, 473029
No. 3 does not describe how to process the light obtained from the recording medium to obtain the recorded information as a signal.

[Problem that the invention seeks to solve]

Therefore, the applicant devised a data processing system shown in FIG. Here, a case is shown in which track n and track n+1 are simultaneously irradiated with light and read.

In FIG. 7, light obtained by irradiating track n is converted into an electrical signal via a photoelectric conversion detection element 11. This electrical signal passes through an amplifier 12.

l! in the binarization circuit 13! The signal is converted twice. After that, the phase comparator 14 V F O (variable freq
(uencyoscillator) circuit 15.

FIG. 7 shows a data processing system when information is recorded using a modulation method using a self-clock.
It constitutes a se-1゜ckedloop) circuit. P
The electrical signal that has passed through the LL circuit is demodulated by the data demodulator 16.

A data demodulated signal 17 is obtained.

On the other hand, the light obtained by irradiating track n+1 also
Similarly to the light obtained by irradiating the photoelectric conversion detection element 21.
Increase @WA22. Binarization circuit 232 Phase comparator 24. VF
O circuit 25. A data demodulated signal 27 is obtained via a data demodulator 26.

The obtained data demodulated signals 17 and 27 are sequentially selected and reproduced as information by a controller (not shown) that controls the entire apparatus.

However, when processing data according to this data processing system, a data processing system corresponding to the number of tracks to be simultaneously irradiated with light and read is required. In FIG. 7, it can be seen that two data processing systems formed from the photoelectric conversion detection element 11.21 and the data demodulator 16.26 are used to read out the two tracks n and n+1.

Therefore, if the data processing system shown in FIG. 7 is used, the problem arises that the scale of the circuit increases and the cost also increases. Furthermore, since there are a plurality of circuit systems and processing is performed using many elements, there is a possibility that data reliability may be lowered.

[Means and operations for solving the problems] In order to solve the above problems, the present invention is capable of transmitting information recorded on a recording medium by irradiating light onto a plurality of recording areas. The system is designed to play back by storing at least a part of the data. By storing at least part of the information in a plurality of recording areas.

This makes it possible to demodulate and reproduce desired information at any desired time.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

1 to 3 are diagrams showing a first embodiment of the present invention. Also in the first embodiment, track n and track n+
A stage in which light is irradiated simultaneously to 1 and 2 will be explained.

The light obtained by irradiating the track n is transmitted to the photoelectric conversion detection element 31
convert it into an electrical signal. This electrical signal passes through an amplifier 32, is converted into a binary signal by a binarization circuit 33, and is input to a selector 34.

A select signal 34a from a controller (not shown) is input to the selector 34, and by this select 34a,
First, the data of track n is sent to the phase comparator 35.

The signal then passes through a PLL circuit composed of a phase comparator 35 and a VFO circuit 36, and then passes through a data demodulator 37 to obtain a demodulated data signal for track n.

On the other hand, the light obtained by irradiating the track n+1 is converted into an electric signal by the photoelectric conversion detection element 41, and after passing through the amplifier 42, is converted into a binary signal by the binarization circuit 43. Up to this point, data processing for track n proceeds simultaneously. After passing through the binarization circuit 43, the data of track n+1 is input to the memory section 44 and stored therein. A reset signal 44a and an R/W (read/write) switching signal 44b from the controller are input to the memory section 44.
The timing for storing data from track n+1 is generated.

An example of the configuration of the memory section 44 is shown in FIG. 2. The memory section 44 includes a clock module 441. It is composed of a counter 442 and a semiconductor memory 443.

When storing the binary signal from the binarization circuit 43 in the semiconductor memory 443, the R/W switching signal 44b instructed by the controller is set to the write state, and the reset signal 44
The counter 442 has been reset by a. The counter 442 is counted up by the clock signal from the clock module 441, and its output is input to the semiconductor memory 443 via the address bus as the address of the semiconductor memory 443. On the other hand, the clock signal from the clock module 441 and the R/W switching signal 44
The write pulse which is the AND output of b is the semiconductor memory 44.
Enter 3. This write pulse is synchronized with the address setting. Binary output of the binarization circuit 43,
That is, the data on track n+1 follows the write pulse,
1 bi at the set address in the semiconductor memory 443
t is stored. At the end of writing data to the semiconductor memory 443, the R/W switching signal 44b is set to the read state. For example, when a card-shaped optical recording medium is used, if the storage capacity of one track is IMbit, it is possible to use an IMbit semiconductor memory because it is the same binary information as recorded on the optical card.

While the data of track n+1 is stored in the semiconductor memory 443, the data of track n+1 is stored from the data demodulator 37.
A data demodulated signal is output. After the data of track n is output, the data of track n+1 is selected to be demodulated by the select signal 34a, and the data stored in the semiconductor memory 443 is read out. The counter 442 is in a read state from the end, and after being reset by the reset signal 44a, the counter 442 counts up, and when the address is incremented, the corresponding track n+1 is read out. Writing to the semiconductor memory 443 and reading from the semiconductor memory 443 are shown in the drawing as being performed using the same terminal, but they may also be performed using semiconductor memories having separate terminals.The read data is transferred to the selector 34. ,
Phase comparator 35. VFO circuit 36. It is obtained as a data demodulated signal for track n+1 via the data demodulator 37.

FIG. 3 is a diagram showing the timing of data storage in the semiconductor memory 443. A is an output signal from the photoelectric conversion detection element, and B is a signal obtained by converting A into a binary value. Regarding track n, demodulation is performed from this binary signal B, C
is an enlarged view of B in the time axis direction for ease of viewing;
In the case of data on track n+1, C is stored at the timing of write pulse D. Therefore, semiconductor memory 4
43 stores the waveform of E.

As shown in FIG. 3E, X and y are semiconductor memory 4
This is the sampling error when storing the data to 43. Generally, when a fluctuation occurs in the time axis direction in optical storage/reproduction or magnetic recording/reproduction, it becomes jitter. The sampling error x''y that occurs here can be similarly considered as jitter.If the amount of jitter due to this sampling can be suppressed to about 5%, it will not have a large effect on data reproduction.

For example, in the case of an optical card, the read speed is 1o.
kbit/sec"1oOk bit/sec, so the frequency of the write pulse should be set to 500 KHz to 5 MHz.
If it is set to about z, the amount of jitter can be suppressed to about 5%.

As mentioned above, in the first embodiment, a memory section is provided, and P
By integrating the data demodulation circuit consisting of the LL circuit and the data demodulator into one system, it becomes possible to simultaneously irradiate light onto a plurality of tracks and read data with a miniaturized circuit configuration.

In this embodiment, a case has been described in which two tracks are irradiated with light at the same time to read out data. However, even if the number of tracks to be irradiated with light simultaneously and data is read out further increases, the data can be read out just like in the embodiment. The number of demodulation circuits can be reduced to one system.

Hereinafter, regarding the second and third embodiments, similar to the first embodiment,
A case will be described in which light is irradiated onto two tracks, but it goes without saying that the same application and configuration can be applied even when the number of tracks increases.

Next, a second embodiment of the present invention will be described based on FIGS. 4 and 5. The same parts as in FIG. 1 of the first embodiment are given the same reference numerals, and details are omitted. The difference from the first embodiment is that in the first embodiment, the writing and reading speeds to the semiconductor memory are the same, whereas in the second embodiment, the reading speed is faster than the writing speed. . Therefore, in the memory section 54, as shown in FIG.
b is set to the write state at the time of writing, and the selector 544 selects the clock module 5 with this write state signal.
41a is selected. According to the clock signal from the clock module 541a, the counter 542 is counted up and the address of the semiconductor memory 543 is set, and a write pulse is also generated at the same time. On the other hand, when reading, the R/W switching magnification signal 5
4b- is set to the read state, and the selector 544 selects the clock signal of the clock module 541b based on the read state signal. The clock module 541b generates a clock signal with a frequency m times that of the clock signal from the clock module 541a during writing. Here, clock modules with two types of frequencies are selected.
Track n may be used to divide the frequency by m using a counter, and it may be selected whether or not to use the counter.
The read speed of the data is determined by the relative movement between the optical head and the recording medium, but for track n+1, the read speed can be increased up to the maximum read frequency determined by the semiconductor memory 543. In this embodiment, The data signal of track n+1 read from the memory section 54 has a frequency m times that of the data signal of track n based on the clock signal from the clock module 541b. Therefore, the phase comparator 55. The time constant of the PLL circuit consisting of the VFO circuit 56 is switched by applying a command signal 55a, and when demodulating the data of track n+1, it is synchronized by multiplying the frequency by m when demodulating the data of track n. PLL with synchronous frequency multiplied by m
The data signal of track n+1 which has passed through the circuit is demodulated by the data demodulator 37 at a speed m times that of track n.

Here, the PLL circuit switches the synchronous frequency by switching the time constant, but there is also a method of digitally matching the phase and frequency, and in this case, the target frequency may be switched.

With the above configuration, it is possible to speed up the reading of -layer information.

Taking an optical card as an example, there is a method of reading information by reciprocating a recording medium. In this case, deceleration and stopping operations are always required when reversing the direction of movement of the recording medium.

Since information cannot be read from the track during this time, if the information stored in the semiconductor memory is demodulated during this time, the efficiency of the read operation will be improved.

Next, a third embodiment of the present invention will be described based on FIG. The same parts as in FIG. 1 of the first embodiment are given the same reference numerals, and details are omitted.

The feature of the third embodiment is that data on tracks that do not pass through the memory section 44 can be selected.

In implementing this, the data of track n and track n+1 that have passed through the binarization circuits 33 and 43 are input to the first selector 64. The first selector 64 selects data to be sent to the second selector 65 and data to be sent to the memory unit 44 in response to a first select signal 64a. For example, the data of track n is input to the second selector 65, and Input the data of track n to the memory section 44 along the broken line route in the figure for inputting the data of n+1 to the memory section 44,
The path indicated by the double line in the figure, which inputs the data of track n+1 to the second selector 65, is selected by the first select signal 64a. The second selector 65 uses the data sent from the first selector 64 and the memory section 4 in response to the second select signal 65a, similar to the selector 34 in the first embodiment.
Select the data to be read from 4. Note that the memory section 4
The method of storing data in the second selector 4, the PLL circuit after the second selector 65, and the demodulation circuit (not shown) are the same as in the first embodiment, and therefore their explanation will be omitted.

As described above, among the information to be read from the tracks, if it is possible to select the information on the tracks that go through the memory section and the information on the tracks that do not go through the memory section, depending on the content of the information recorded on the tracks, multiple If the track to be read out first among the tracks has been determined, by selecting one, the data of that track can be demodulated without going through the memory section, so it can be demodulated first. Furthermore, since the information does not go through the memory section, this information does not include jitter due to sampling.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications are possible.6 For example, in the embodiments, the data of a certain track is always demodulated without going through a storage means, but all the data After the track data is stored in the single storage means, it may be demodulated by a single demodulation circuit.

In addition, U, S, and FAT cited as prior art.

In No. 4730293, a plurality of tracks are irradiated with light with one light beam, but this may be applied as is to the present invention, or a plurality of tracks may be irradiated with a plurality of beams. , U, S, FA in the example
T, No. 4730293, we have explained the case where multiple tracks are irradiated with a light beam at the same time, but when there are multiple sectors on the same track, there is a case where each sector is irradiated with light at the same time to reproduce information. The present invention can also be applied to

〔Effect of the invention〕

As explained above, according to the present invention, when reproducing information by irradiating light onto a plurality of recording areas on a recording medium, by storing at least part of the information in the plurality of recording areas, the desired information can be stored. In order to make it possible to demodulate desired information at the time of recording, the number of demodulating means can be made smaller than the number of recording areas irradiated with light, so that high-speed reproduction of information can be realized with a compact reproducing apparatus.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention, FIG. 2 is a block diagram showing an example of the configuration of the memory section used in FIG. 1, and FIG. 3 is the operation timing of the memory section in FIG. 1. FIG. 4 and FIG. 5 are block diagrams showing the configuration of the second embodiment of the present invention, FIG. 6 is a block diagram showing the configuration of the third embodiment of the present invention, and FIG. 7 is a block diagram showing the configuration of the third embodiment of the present invention. FIG. 2 is a block diagram for reproducing information that was conceived by a person. 44.54...Memory part, 34.64.65.544
...Selector, 441.541 a, 541 b
- Tarock module, 442.542...Counter, 443.543...Semiconductor memory.

Claims (1)

[Claims] 1. In a device that reproduces information by irradiating light onto a plurality of recording areas on a recording medium, information is modulated and recorded in the plurality of recording areas, and the plurality of recording areas are means for converting the returned light from the irradiated recording medium into an electrical signal as information of each recording area; means for storing at least part of the information of the plurality of recording areas converted into the electrical signal; An optical information reproducing device comprising means for demodulating information in a recording area to be read. 2. The optical information reproducing apparatus according to claim 1, wherein the plurality of recording areas to which the light is irradiated are plural tracks. 3. The optical information reproducing apparatus according to claim 1, wherein the plurality of recording areas to which the light is irradiated are a plurality of sectors. 4. The optical information reproducing apparatus according to claim 1, wherein the light irradiated to the plurality of recording areas is a single light beam. 5. The optical information reproducing apparatus according to claim 1, wherein the light irradiated onto the plurality of recording areas is a plurality of light beams. 6. Claim 1, wherein the information stored in the storage means is binary information.
The optical information reproducing device described above. 7. The optical information reproducing apparatus according to claim 1, wherein the information in at least one recording area among the information in the plurality of recording areas is demodulated without using a storage means. 8. The optical information reproducing apparatus according to claim 7, wherein information transmitted through the storage means is demodulated at a higher speed than information not transmitted through the storage means. 9. The optical information reproducing apparatus according to claim 1, wherein the information from the storage means is demodulated during a period when the return light from the recording medium is not converted into an electrical signal.