JPS6267771A - Discriminating device for recording media - Google Patents

Abstract

PURPOSE:To execute the coping with even when the type of the recording media is different by providing an index mark to show the type, etc., at the recording media and reading the information of the index mark facing to the recording media. CONSTITUTION:When the rotation position of a rotated disk 3 comes to be the condition facing to a photo reflector 5 by an index mark 4, corresponding to a length D of the index park 4, only for the time (t) when the facing condition continues, the electric current flows at the photodetecting element, and the pulse of the width (t) is outputted from a waveform shaping circuit 7. Only for the pulse width period of the pulse, an AND circuit 8 as the gate is opened, the clock pulse of a clock generator 11 is impressed to a counter circuit 12 and the clock pulse is counted. By the counted value output of a latch circuit 15, for a decoder 16, some output edge 16i facing to the index mark 4 comes to be a high level, the type of the actually fitted disk 3 is identified, and the control system of the recording reproducing device and the signal processing system to record and reproduced are selected and set to the condition suitable to the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION τIndustrial Field of Applicationj The present invention relates to a recording medium discriminating device provided with means for discriminating the recording medium used.

[Background Art] In recent years, the progress of information-related industries has been remarkable, and the amount of information being handled is also rapidly increasing.

Therefore, instead of using conventional magnetic heads to record and read information, optical heads that use light can be used to record at high density and play back at high speeds. Optical information recording and reproducing devices are attracting attention.

Various types of optical recording media have been proposed for use in the above-mentioned optical recording/reproducing apparatus, and currently the following types of recording media are being put into practical use.

For write-once recording media, (a) those using a perforation method using a metal thin film, (b) those using a perforation method using an organic dye, and (C) reflectance changes using quality and amorphous changes. There is a method.

On the other hand, rewritable types include (b) magneto-optical type, (e
) quality, amorphous changes are used.

Of course, these various recording media have different writing destinations,
The reflectance after writing varies, such as <a), (b), (0) decreases, (C) increases, and (d) does not change. A magnetic field generation mechanism is required because the magnetization direction must be reversed. Further, in this case (d), since the reading uses the rotation of the polarization plane of the repulsed light, the reading light must be linearly polarized light. Conventional devices have been designed to operate in accordance with a specific recording medium without giving any consideration to compatibility with each recording medium.

[Problems to be solved by the invention] For example, in the recording medium (a), the amount of reflected light from the medium decreases after recording, and the servo gain of focus servo, track servo, etc. decreases, so the amount of reflected light from the recording medium decreases. It detected the change and increased the servo gain. If the recording medium (C) is used in such an apparatus, the gain after recording increases too much, making the servo unstable, resulting in drawbacks such as inability to perform stable reading. Furthermore, if the media of (a) to (e) have different recording densities, writing may not be possible depending on the recording medium.

Furthermore, since the amplitudes (output levels) of signals reproduced by recording media of different recording methods differ, problems arise such as, for example, a signal level that should originally be identified as a high level is erroneously reproduced as a low level. Therefore, it is necessary to determine the type of recording medium and perform an operation suitable for that recording medium.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a recording medium discrimination device that can handle cases where the types of recording media are different.

[Means for Solving the Problems and Their Effects] In the present invention, a recording medium is provided with an index mark indicating its type, and the information on the index mark is read by facing the recording medium, and recording suitable for the disc is performed. , playback, etc.

[Example] Hereinafter, the present invention will be specifically described with reference to the drawings.

Figures 1 to 3 relate to the first embodiment of the present invention.
The figure shows a discrimination circuit of the first embodiment, FIG. 2 shows a disk as a disc-shaped recording medium used in the first embodiment, and FIG. 3 shows a timing chart for explaining the operation of the first embodiment. show.

The discrimination circuit 1 of the first embodiment is mounted on a disk 3, which is a disk-shaped optical recording medium rotationally driven by a spindle motor 2, so as to be able to read an index mark 4 provided on the disk 3 for identifying the recording medium. A photoreflector 5 is provided.

The disk 3 used in the first embodiment is formed into a disk shape of glass, plastic material, etc., and has a hole for clamping in the center, and a concentric hole (
or a spiral) information recording track is formed.

A portion other than the regular recording area where the information recording track is formed, for example, the innermost track (referred to as THIN).
For example, a metal film is attached to the inner surface of the index mark 4 to provide an index mark 4 having a reflectance different from that of the part to which the metal film is not attached.

This index mark 4 is provided as information about the disc 3 so that the length in the circumferential direction and the angle) D differ depending on the type of disc 3. A photoreflector 5 that detects this index mark 4 emits light. It consists of a light-emitting element and a light-receiving element that receives reflected light from the light emitted from the light-emitting element onto the disk as an object, and this light-receiving element outputs a detection signal with a pulse width corresponding to the length of the index mark 4. , this output is input to the waveform shaping circuit 7. This waveform shaping circuit 7 amplifies the input signal and binarizes it using a comparator, with almost no noise (
This digital signal is applied to one input terminal of a two-man AND circuit 8, and is also applied to a one-shot (multivibrator) circuit 9 to detect its falling edge. Then, a pulse is output as shown in Fig. 3. When the clock pulse of the clock generator 11 is applied to the other input terminal of the AND circuit 8, and the output of the waveform shaping circuit 7 is at a high level, the lock pulse is applied to the clock pulse of the counter circuit 12 as shown in FIG. 3C. Applied to the terminal.

The output signal of the one-shot circuit 9 is applied to the reset terminal R of the RS flip-flop 13, and the voltage VCC at the power supply end is applied to the -10,000 set terminal S via the resistor r, and the ground via the switch SW. connected to the terminal.

The above switch 1 switch is normally turned on, and the disk 3
This is a memorabilia-type switch that opens temporarily when it is attached to the turntable. Therefore, as shown in FIG. 3d, a pulse is applied to the set terminal S, which is normally at a low level and temporarily becomes a high level when a disk is loaded. The output of the output end of the output terminal becomes high level, and when the reset terminal R is subsequently set to high level, it outputs a pulse that becomes low level (as shown in FIG. 3e).

The output of the RS flip-flop 13 is the counter circuit 1
The output of the counter circuit 12 is applied to the latch enable terminal of the latch circuit 15 to which the output of 2 is applied, and the count value of the counter circuit 12 is latched at the falling edge of the signal applied here becoming low level, and the value is held and the decoder The voltage is applied to the circuit 16.

Further, the output of the RS flip 70 knob 13 is applied to the clear terminal (reset terminal) FT of the counter circuit 12 via the delay circuit 17, and from the timing when this output becomes high level (for example, several tens [ ms]) Resets the count value after a delay.

By applying the output of the latch circuit 15,
The decoder circuit 16 outputs output terminals 16a, 16b, . . . corresponding to the type of disc in accordance with the applied count value.
, 16e becomes high level.

For example, when 16a is at a high level, the disk is automatically identified as having a hole, and when 16b is at a high level, the disk 3 is automatically identified as using an organic dye.

Either terminal 161< corresponds to the type of disk mentioned above.
When t-a, b, ..., e) becomes high level, that high level signal is used as a control signal,
It is possible to selectively set the recording/reproducing device to a control state and a recording/reproducing state corresponding to the disc.

For example, parameters such as the resistance value for setting the amplification factor are selectively set so as to increase the gain of the tracking servo system and focus servo system for a disk with a small amount of reflected light D, and to decrease the gain of the servo system for a disk with a large amount of reflected light D. Further, it is possible to select and set the light intensity of the laser diode and the level of the detection signal so as to obtain an appropriate signal level for each recording or reproduction mode.

Further, if it is identified as a magneto-optical disk, a switch or the like can be changed so that current flows in a predetermined direction through the magnetic coil in recording mode or erasing mode.

The output of the waveform shaping circuit 7 is used as an index signal.
This command is used to instruct whether or not to perform a track jump every rotation, depending on whether the tracks on the disk are spiral or concentric.

The operation of the first embodiment configured as described above will be explained with reference to FIG.

As the disk 3 is inserted into the recording/reproducing apparatus equipped with the first embodiment and set to a predetermined loading state, the switch S is turned on.
W changes from on to A, and then turns on again after a certain period of time.

Accordingly, as shown in FIG. 3d, the set terminal S of the RS flip-flop 13 is set by applying a pulse of positive polarity or high level, and the output of the output terminal of the RS flip-flop 13 is set to the set terminal S of the RS flip-flop 13. The level becomes high as shown in Figure 3e. This output is applied to the reset terminal of the counter circuit 12 via the delay circuit 17, and after a short delay time, the counter circuit 12 is set to a countable state. When the rotational position of the rotated disk 3 is such that the index mark 4 faces the photoreflector 5, the light-receiving element is exposed to the light receiving element for a time t during which the index mark 4 remains facing the photoreflector 5, corresponding to the length D of the index mark 4. A current flows, so that the waveform shaping circuit 7 outputs a pulse having a width t as shown in FIG. 3a.

The AND circuit 8 serving as a gate is opened during the pulse width period of the above-mentioned pulse, and therefore, the clock pulse of the clock generator 11 is applied to the counter circuit 12, and the clock pulses are counted.

When the output of the waveform shaping circuit 7 becomes low level, the one-shot circuit 9 is activated at the fall, and a pulse is output as shown in FIG.
output to low level.

When this output falls to low level, latch circuit 1
5 latches the count value of the counter circuit 12 and outputs it to the decoder circuit 16, and after a slight delay, the counter circuit 12 is reset.

The decoder 16 receives the count value output from the latch circuit 15.
is either output end 1 corresponding to index mark 4
6i becomes high level and disk 3 is actually installed.
The type of disc is identified, and the control system of the recording and reproducing device and the signal processing system for recording and reproducing are selected and set in a state suitable for that disc.

After the disk 3 is loaded, if the index mark 4 of the disk 3 is detected again, the output of the RS flip-flop 13 is held at a low level.
The counter circuit 12 is held in an inactive state, and the latch circuit 15 continues to hold the count value determined at the first rotation.

In this way, the type of disc 3 is detected and its data is retained.

FIG. 4 shows a discrimination circuit 21 of a second practical example of the present invention.

The discrimination circuit 21 of the second embodiment is an improvement on the first embodiment, and detects the index mark when the disk 3 reaches a constant rotation speed. Without using the example resistor r and switch SW,
(Index mark) Discrimination timing setting circuit 22 is provided.

That is, the output of the waveform shaping circuit 7 is inverted by the inverter circuit 23 and applied to the integrating circuit 24.

The integrator circuit 24 has its input terminal connected to the non-inverting input terminal of a differential amplifier (op-amp) 25, and its inverting input terminal connected to the ground via a resistor R and to the output terminal via a capacitor C. An integrating circuit 24 is formed by the above.

The output of the inverter circuit 23 is connected via a delay circuit 26 to a control end of an analog switch 27 that turns on and off both ends of the capacitor C.

When the signal passed through the delay circuit 26 is at a high level, the analog switch 27 is turned off, and when it is at a low level, the analog switch 27 is turned on to discharge the charge in the capacitor C.
The output of the integrating circuit 24 is made zero.

Further, the output of the inverter circuit 23 is applied to a control terminal C of a sample and hold circuit 28 where the output is sampled and held, and the input voltage is held at the edge of falling to a low level. The output of this sample and hold circuit 28 is input to a window comparator 29, and is applied to the other input terminals of comparators 30A and 30B, each of which has a reference voltage fIVH, VL (VH>VL) applied to one input terminal. The outputs of the comparators 30A and 30B are applied to a one-shot circuit 32 via an AND circuit 31. The AND circuit 31 includes a comparator 30A,
The output voltage ■ of the sample and hold circuit 28 applied to 30B becomes high level only when VL < V < VH, and at the rise to this high level, the one shot circuit 3
2 is activated to output a pulse, and this output is applied to the set terminal S of the RS flip-flop 13.

The reference voltages VL and VH are determined from the values obtained by integrating the inverted signal of the waveform shaping circuit 7 by the integrating circuit 24 for a time interval of approximately one period during which the index mark 4 is detected when the disk 3 reaches a constant rotation speed. It is set to a slightly smaller value and a slightly larger value. Therefore, actually the integrating circuit 24
If the value integrated through the reference voltages VL and VH is between these reference voltages VL and VH, it means that the disk 3 has reached a predetermined constant rotation speed, and in this state, the set terminal S is set to high level and the RS flip-flop The output terminals of the pull-up 13 become high level.

The rest of the structure is the same as that of the first embodiment.

The operation of the second embodiment will be explained below with reference to FIG.

As the disk 3 is loaded into the recording/reproducing device and the disk 3 is rotationally driven by the spindle motor 2, a detection signal is output every time the index mark 4 crosses the photoreflector 5, and this signal is waveform-shaped by the waveform shaping circuit 7. As shown in FIG. 5 a', a high level signal a' corresponding to the rotational speed of the disk 3 and the length of the index mark 4 is output.

The signal a- is inverted by the inverter circuit 23 and has a waveform as shown in FIG. 5Q.

When the signal q becomes high level, the signal is integrated by the integrating circuit 24, and a sawtooth wave is output as shown in Figure 5. This sawtooth wave is held by the sample and hold circuit 28 at the falling edge when the signal q becomes low level, and is input to the window comparator 29. The voltage of the input signal input to the window comparator 29 is
When the disk 3 has just started to be rotated, the rotation speed of the disk 3 is slow, so the period of one rotation of the disk is long, and therefore the integration period is also long (large), so the output level of the sample and hold circuit 28 is It becomes larger as shown in Figure 5i. However, the rotation speed gradually increases,
As the speed approaches constant speed, "C1 sample hold circuit 2
The output level of the AND circuit 31 gradually becomes lower, and when it reaches a level between the reference voltage VH and the lower limit, the output of the AND circuit 31 becomes high level as shown in FIG. Therefore, at the rising edge when the output of the AND circuit 31 goes high, the one-shot circuit 32 applies a high-level pulse to the set terminal S as shown in FIG. A is set to a high level to set the counter circuit 12 to a countable state.

On the other hand, when the output of the waveform shaping circuit 7 becomes a high level according to the length of the index mark 4 corresponding to the type of the disc 3, a clock pulse is applied to the counter circuit 12 by passing the AND circuit 8 during the high level period. , the period of its high level clock pulses are counted. The output of the counter circuit 12 is latched by a latch circuit 15, and the output of this latch circuit 15 is sent to the decoder circuit 16 at output terminals 16a, 1.
The output terminal 161 corresponding to the type of disc 3 among the output terminals 6b, .

The operation other than the above-mentioned judgment time setting circuit 22 part is the above-mentioned first one.
This is similar to the example.

According to the second embodiment, it is possible to reliably read (distinguish) the index mark indicating the type of disc 3, etc.

In the first embodiment as well, after the disk 3 is loaded, the discrimination circuit 1 is operated after the time required for the disk to rotate at a constant speed, so that the information based on the index marks can be reliably read. You can do it like this.

In this case, for example, a timer may be operated and the output of the timer may be inputted to the waveform shaping circuit 7 at the subsequent stage.

In the present invention, the index mark that does not represent information such as the type of the disc 3 is not limited to the one described above, but may be one that has a different reflection level depending on the type of disc. In this case, first, following the foul mark that is the same for all discs, index marks may be provided so that the reflection level differs depending on the disc, and if the detection signal of this index mark is AD converted, the disc The type can be determined.

Alternatively, the type of the disc may be determined by providing an index mark in the form of a bar code or by counting the number of pulses input during one revolution of the disc.

Note that the index mark can be provided at any location other than the regular information recording area.

Incidentally, the index marks in the present invention include records,
It can be used to determine the information that needs to be set to different parameters from the original disk when performing either playback or erasing, but it is not limited to information that simply distinguishes the type of disk, etc. By also incorporating information regarding recording, playback, and erasure modes, it is possible to reduce the burden on the recording and playback device.

For example, following the index mark 4 of the first or second embodiment, information such as amplifier gain for signal detection in recording mode, light emitting output setting information of a laser diode, etc.
It is also possible to provide information marks or information patterns such as amplifier gain for signal detection in the reproduction mode, information for setting the light emission output of the laser diode, and information on the light emission output of the laser diode in the erase mode. Depending on the disc, the corresponding information pattern section above may be left blank, so that the corresponding parameter setting is not required for that disc.
That's fine.

In the present invention, the recording medium is not limited to a disk,
It can also be applied to card-like items.

Furthermore, the invention is not limited to those in which information is optically recorded, reproduced, or erased, but can also be applied to discrimination of electrostatic recording media and other recording media.

[Effects of the Invention] As described above, according to the present invention, an index mark indicating the type of recording medium, etc. is provided on the recording medium, and
Since the reading means is provided on the index mark facing the recording medium, the recording or reproducing apparatus can be set and used in a state suitable for the recording medium to be used.

[Brief explanation of drawings]

Figures 1 to 3 relate to the first embodiment of the present invention.
The figure is a block diagram showing the configuration of the first embodiment, and the second figure is a block diagram showing the configuration of the first embodiment.
An explanatory diagram showing a disk used in the embodiment, FIG. 3 is a timing chart diagram for explaining the operation of each part of the first embodiment, and FIG. 4 is a block diagram showing the configuration of a second commercial example of the present invention. 5 are timing charts for explaining the operation of each part of the second embodiment. 1...Discrimination circuit, 3...Disk, 4
... index mark, 5 ... photoreflector, 7 ... waveform shaping circuit, 11 ... clock generator, 12 ... counter circuit 13 ... RS flip-flop 15 ... latch circuit, 16 ...Decoder circuit.

Claims (1)

[Claims] An index mark indicating the type of recording medium, etc. is provided in a portion of the recording medium on which information is recorded, reproduced, or erased, other than the regular information recording area, and the index mark is read by facing the recording medium. A recording medium discriminating device characterized by being provided with means.