JPS5972682A - Optical recorder and reproducer - Google Patents

Abstract

PURPOSE:To attain readout and write of normal information on a desired face and to prevent mis-recording by irradiating a front/back discriminating track provided with a front/back discriminating mark by a light source different from that for information to discriminate the side of the disc. CONSTITUTION:A front/back discriminating track region 3 located at the inside of the information recording region 2 of the disc 1 is irradiated by a light source different from that for information, and the front/back discriminating mark formed with a reference mark 4 and a comparison mark provided at an asymmetric position to the center of the region 3 is detected by the reflected light. Further, the front or back side of the disc 1 is discriminated from the elapsed time from extending the detection of the mark 4 to the detection of the mark 5, allowing to read and write normal information on the desired face. Moreover, the generation of mis-recording such as an unnecessary overlapped recording is prevented surely.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to optically recording and/or reproducing information on a disc-shaped information carrier (optical disc) capable of optically recording and/or reproducing information. In particular, when an optical disc is installed in the optical recording and reproducing apparatus, it is configured so that the entire surface of the disc that is irradiated with a minute spot light from a laser can be detected, regardless of whether it is the front or the back. It is.

Conventional configuration and its problems As an optical information recording/reproducing device, for example, an optical disk coated or vapor-deposited with a photosensitive material is rotated.
A beam of light from a laser light source is applied to the optical disk with a diameter of 1
By irradiating a minute spot light focused to micrometers or less and modulating its optical output intensity with a signal, it is possible to change the phase change, refractive index change, or reflectance due to unevenness on the optical disk.
There is an apparatus that can record information such as a video signal or digital signal in real time as an optical change such as a change in transmittance, and can reproduce the recorded information by detecting one of the changes in optical characteristics.

In such devices, optically detectable guide tracks are provided in advance in the form of concentric circles or slits on the tracks to be recorded in order to increase the density of recording tracks, discrete partial writing, erasing, etc. an optical information recording and reproducing device that records information on a predetermined trunk by applying a conventionally known tracking control sound so that a minute spot light by a laser follows the guide track, and reproduces information from the track. Conceivable.

The guide track formed on the optical disk is suitably a groove-like structure having unevenness, for example, and information is recorded on a recording medium deposited on the groove of the guide track.

In the information record of the device, the disk is rotated in a fixed direction and information is recorded on the guide track 76, so the information on the disk is arranged either clockwise or counterclockwise. Fixed.

On the other hand, there are two types of optical discs: single-sided discs that record information on only one side, and double-sided discs that record information on both sides.

On a single-sided disc that has a structure that allows recording from the side opposite to the normal recording side, if information is recorded on the trunk from the back side, when the track is played back on the front side, the arrangement of the information will be reversed from the normal arrangement, so the writing will be difficult. It becomes impossible to read out the information.

Also, if you record from the back side onto a track that has already been recorded on the front side, the legitimate recorded information on the front side will be destroyed. Therefore, when a single-sided disc is loaded into the device, it is determined which side is the recording side, and if the side irradiated by the laser is the non-recording side, the laser is turned on to prevent writing errors. It is necessary not to let it emit.

In addition, with double-sided discs, both the front and back sides have information recording areas, but if you try to record on the front side and the disc is inserted backwards, and you accidentally record your words on the back side, the information you write may be damaged. Around 11 days ago, a quarrel broke out. Unfortunately, if you record information incorrectly when it has already been recorded, you will destroy the previously recorded information. Therefore, even when a double-sided disc is installed in the device, the user must determine whether the laser will irradiate the desired surface, and if it is installed in the opposite direction, the laser should not be irradiated to prevent erroneous recording. 0 Purpose of the Invention The present invention solves the above problem by determining the front and back sides of a disc and confirming that the surface irradiated with a laser for recording and reproducing information is the surface desired by the user. After that, the laser is emitted to perform focus and tracking control.

Composition of the Invention The present invention provides a front/reverse discrimination mark provided in a front/reverse discrimination trunk area of an optical disc.
means for detecting using a second light source different from the light source;
An optical recording/reproducing device is equipped with a means for discriminating between the front and back of an optical disc based on a detected front/reverse discrimination mark signal. This prevents erroneous recording on the disc by emitting light from the first light source after confirming that the surface is the same as the one shown in FIG.

Description of examples The drawings therefore provide a detailed explanation of the invention.

FIG. 1 is a plan view showing the structure of an optical disc having front and back discrimination marks detectable from both sides, used in an optical recording/reproducing apparatus according to a first embodiment of the present invention.

The optical disc 1 is composed of an information recording area 2 consisting of a groove-shaped guide trunk and a front/back discrimination track area 3 for distinguishing between the front and back sides of the disc. On the front/reverse discrimination track, there is a reference mark that can detect both sides. A comparison mark 5 is formed to compare the position of the reference mark 4 and the other reference mark 4. The reference mark 4 and the comparison mark 5 are arranged so as not to be symmetrical with respect to the center of the disk.

FIG. 2 is a perspective view of the basic structure of these two marks. Both marks are made up of a guide l/rack piece group 7 in which guide track pieces 6, each having the same groove as the guide track in the information recording area and an arc angle α of the optical disk, are aligned for a plurality of tracks.

FIG. 3 shows an example of the configuration of both marks. Both marks are i1■
Distinction is made by varying the number of recording guide track segment groups arranged. Figure 3a shows the structure of the reference mark 4, in which a group of guide track pieces 7 whose length in the circumferential direction is equal to the arc angle α of the disk and whose length in the radial direction is h, as shown in Figure 2, are arranged at an arc angle There are three arrays arranged at intervals of α. FIG. 3 shows the structure of the comparison mark 6, which is composed of one group of guide track pieces labeled i''lJ.

At this time, the entire portion of the front/back discrimination trunk other than both marks is a flat portion. FIG. 4 is an example of a mark detection device for detecting both marks.

In FIG. 4, the optical disc 1 is being rotated by the morph 8 at a constant rotation speed. Mark detector 9 (1) consists of a light-receiving element that focuses a light beam emitted from a light-emitting element by an optical reflective sensor onto a front/back discrimination track 3 on the optical disk 1, and converts the reflected source metal into photoelectricity. Since it has a uniform phase ?f/# structure, the groove portion scatters the light, and the reflected light shade that enters the light receiving element of the mark detector 9 is reduced, thereby detecting the mark.Mark detector 9 After being amplified by the output I-J amplifier 10, it passes through a bandpass filter 11 and is pulse-shaped by a comparator.

FIG. 6 shows signals of each part in FIG. 4. Since the output signal 13 of the amplifier 10 undergoes an amplitude change as shown in No. 6 Na due to vibrations of the optical disc 1 or fluctuations in surface reflectance, the band is limited by the bandpass filter 11 to remove this fluctuation component. As shown in FIG. 5, the output 14 of the range filter 11 has the above fluctuation component removed, and is binarized by the comparator 12 using the value voltage VR. The output 16i of this lake 12 is shown in FIG. 6.゛Figure 6a shows the comparator output 1 word 1 of the reference mark and comparison mark that can be detected from both sides when the disc is placed face up.
It is 6. b is the same number 19 when installed face down. As is clear from the figure, if the reference mark and comparison mark are placed in positions that are not symmetrical with respect to the center of the disc, the difference will occur when the disc is installed face up and when it is installed face down. Period T1 during which the disk rotates once
Comparison mark signal 1 from reference mark 1 word 16 within
The time in 7 games changes from T2 to T3. Therefore, by checking whether or not the comparison mark 1 word 17 is detected within a certain period of time after the reference mark signal 16 is detected, it is possible to detect which direction the disk is mounted.

FIG. 7 shows an embodiment of the disk front/back discrimination circuit shown in the first embodiment. FIG. 8 shows signal waveforms at various parts in FIG. 7.

Now, without emitting the laser for recording and reproducing information, only the disk morph is turned and the front/back discrimination mark signal 16 is sent to the input terminal 18 of this front/back discrimination circuit as shown in FIG.
manually. This signal 150 is a signal for detecting the comparison mark signal 17 within half a rotation after the reference mark signal 16 is detected. The time constant of the retrigger type monomulti 20 is set to be thicker than the pulse cycle width T4 of the base candy mark. The output 22 of the mono multi 20 is I for Funou/Re 21.
Do not count when "I, l" +l Start counting/tossing the clock 23 in the state of HI+. Increase the set price of the digital controller ζ rake 24, output when it matches) s) If the response is a comparison mark, output, Also, set the value so that it will be output after the last pulse of the starch syrup mark has finished outputting.In other words, if there is only one pulse like the comparison mark, the output 25 of the comparator 24 will be output, and two or more pulses like the reference mark will be output. The comparator 24 is set so that it is output only when the signal is input.

After a matching pulse is output from the conoparator output 26, NAN and D are obtained from the output 27 of the monomulti 26, the front/back discrimination mark signal 15, and the motor rotation synchronization signal 28, and the comparison mark of the front/back discrimination mark signal 15 is detected. Set the time constant of MonoMulti 25 as follows. When the NAND output 29 is output, the signal DMON3C to turn on the motor)
The Q output 32Q of the flip-flop 31, which has been reset to "L" by the rising and falling of the signal, becomes "H".

In other words, if the entire circuit is set so that if all comparison marks are detected within half a rotation after the reference mark is detected, the Q output 32 of the flip-flop 31 will be 6H'', and this disk is installed in reverse. In the case of the front/reverse discrimination mark signal b1 at the time, the Q output of the flip-flop is up to 1 of L'', and it is possible to discriminate between the front and rear sides of the disk by the Q output of the flip-flop.

After determining the front and back sides, the CPH controls to check whether the laser for recording and reproducing information is irradiated to the desired side of the user, and if it is normal, after checking, the laser is emitted, Apply focus tracking control.

As described above, according to the first embodiment, in a disk having a front and back discrimination mark that can be detected from both sides with the configuration shown in FIG. After confirming the loading direction of the disc, a laser is emitted to record and reproduce information.
It is possible to prevent erroneous writing on the side opposite to the desired side.

Next, a second embodiment of the present invention will be described with reference to all the drawings.

FIG. 9 shows the structure of an optical disc in which there are independent front/reverse discrimination track areas on the front and back sides, and the front/reverse discrimination mark on each trunk cannot be detected from the opposite side. The front/reverse discrimination track 3 of the optical disc 1 is located on the same circumference on the front and back sides, and only a reference mark 34 is formed at an arbitrary position on the front/reverse discrimination track on the front side, and on the front/reverse discrimination trunk on the back side. Only the comparison mark 35 is formed at an arbitrary position. The reference mark and the comparison mark have the same phase groove structure as shown in the first embodiment, the reference mark is composed of the three guide trunk piece groups shown in FIG. It consists of one guide track segment group shown in .

FIG. 10 shows the output signals of both marks detected by the gate device shown in FIG. 3.

Figure 10a shows the signal 37 detected from the front/reverse discrimination track on the front side, in which only the reference mark signal 16 is detected, and Figure 8 shows the signal 49 detected from the front/reverse discrimination track on the back side.
In this case, only the comparison mark signal 1γ is detected.

FIG. 11 shows one block of the front/back discriminating circuit in the second embodiment of the present invention, and FIG. 12 shows one detected word of each part.

As in the first embodiment, the laser for recording and reproducing information does not emit light and only the disk motor is rotated, and the front/back discrimination mark signal 37 shown in FIG. 12 is input to the front/back discrimination circuit input terminal 36 of FIG. 11. do. This signal is a signal in which only the reference mark is detected.

Counter 38il-j: Re-trigger type mono multi 3
When the output of clock 9 is "L", it does not count, but when the output of clock 41 is ++H++, it starts counting. Digital co/
The setting value of Paragraph 42 is that the pulse to be checked is output when there is only one iZ) reply like the comparison mark signal, and only when two or more pulses are input like the reference mark signal. Set it so that it will be output. After a coincidence detection signal is output from the control/punk output 43, the motor rotation synchronization signal 44 and NAND are taken, and this NAND output 4
When 5 comes out, the signal DMON4 when turning on the moku
The Q output 4B of the flip-flop 47, which has been reset to Ln due to the low rise of 6, is set to "H" (C7).

In other words, if the circuit is set so that the Q output 48 of the flip-flop becomes H" when the reference mark is detected,
For example, when there is only a comparison mark signal and no reference mark signal, such as the front/back discrimination mark signal 49 in FIG. 12, or
If there is no signal, flip-flop Q output 48i
d″L++ is only 1, and the front and back sides of the disc can be determined by this Q output.

After identifying both the front and back sides, the CPTr is controlled to check whether the laser for recording and reproducing information is irradiated on the side desired by the user. If it is normal, after checking, the laser is emitted and focused. Tracking control costs money.

As described above, according to the second embodiment, there are two independent front/back discrimination tracks on the front and back sides, and as shown in FIG. Even if a disc has no front/reverse identification marks, it is possible to distinguish between the front and back sides by simply rotating the disc motor.After confirming the mounting direction of the disc, a laser is emitted for recording and reproducing information to identify the desired side. Erroneous recording on the opposite side can be prevented.

In both the first and second embodiments, the front/reverse discrimination track area is located inside the information recording area, but it is needless to say that it may be located outside.

Effects of the Invention The optical recording/reproducing device of the present invention is an optical disc having a front/reverse discrimination track formed with a front/reverse discrimination mark on the inside or outside of an information recording area, and uses a light source different from the light source for recording/reproducing information. By this, it is possible to identify the front M of the disc, and after confirming that the disc is placed in the direction desired by the user, the light source for recording and reproducing information is emitted, thereby allowing normal information to be displayed on the desired surface. Reading and writing are possible, and erroneous recording on the disk can be prevented, which has great practical effects.

Fig. 1 is a plan view of the first embodiment of the optical disc used in the present invention, Fig. 2 is an enlarged perspective view of the front/back discrimination mark of the same optical disc, and Fig. 3 is a comparison with the reference mark of the same optical disc. FIG. 4 is a block diagram of main parts showing one embodiment of the front/back discrimination mark detection device of the present invention, FIG. 5 is a waveform diagram of detection signals of each part in FIG. 4, and FIG. 6 is a plan view showing the structure of the mark. 1st
FIG. 7 is a block diagram of the front/back discrimination circuit in the first embodiment of the present invention, and FIG. 8 shows the signals of each part in FIG. 7. 9 is a plan view of the second embodiment of the optical disc used in the present invention, and FIG. 10 is a waveform diagram of one word for front/back discrimination mark detection on the optical disc of the second embodiment. FIG. 11 is a block diagram showing a front/back discrimination circuit in a second embodiment of the present invention, and FIG. 12 is a waveform diagram of each tone signal of the circuit shown in FIG. 11.

1...Optical disc, 2...Information recording area, 3...Front/backside discrimination track area, 4...
...Reference mark, 6...Comparison mark, 9...
・Photodetector, 16...Reference mark 1 word, 17...
...Comparison mark signal.

Name of agent Patent attorney Toshio Nakao Vli・1 person No. 1 Figure 1 2ryj Figure 3 Figure 4 Figure 5 Figure 6 A laser for recording and reproducing information is irradiated onto the desired surface of the figure. If it is normal, the laser is emitted after checking to perform focus tracking control.

As described above, according to the second embodiment, there are two independent front and back discrimination tracks, and as shown in FIG. 10, one front and back discrimination track has a reference mark, and the other Even for discs with front and back distinguishing marks that do not have front/reverse markings, it is possible to use optical discs with disc marking tracks that do not have a front/reverse distinguishing mark. , it is possible to distinguish between the front and back sides of a disc, and after confirming that the disc is installed in the user's desired orientation, the light source for recording and reproducing information is emitted, allowing normal reading and writing of information on the desired side. This makes it possible to completely prevent erroneous writing on disks, and its practical effects are significant.

By simply rotating the disk completely, it is possible to distinguish between the front and back surfaces, and by emitting a laser for recording and reproducing information after confirming the mounting direction of the disk, it is possible to prevent erroneous recording on the side opposite to the desired side.

In both the first and second embodiments, the front/back discrimination track area is located inside the information recording area, but it is not a matter of course that it may be located outside.

Effects of the Invention The optical recording/reproducing apparatus of the present invention is a plan view of a second embodiment of an optical disc in which a front/reverse discrimination mark is formed on the inside or outside of an information recording area.
FIG. 11 is a waveform diagram of front and back discrimination mark detection signal waveforms in the optical disk according to the second embodiment of the present invention.
FIG. 12 is a block diagram showing the f=IJfflJ circuit. FIG. 12 is a waveform diagram of each sound [word] of the circuit shown in FIG.

1...Optical disc, 2...Information ga
u area, 3... Front/back discrimination track area, 4...
Reference mark, 6... Comparison mark, 9...
・Light detection heat shield, 16 ・Reference mark signal, 17...
... Comparison mark 1 word.

Claims (3)

[Claims] (1) Information is recorded in the information recording area of an optical disc, which has a front/reverse discrimination track area on the inner side or outer side of the information recording area, and a front/reverse discrimination mark having a phase groove structure is formed on the front/reverse discrimination track area. a first light source for reproduction; a second light source for illuminating the front/back discrimination track; a photodetector for receiving reflected light from the front/back discrimination track; and a front/back discrimination based on the output of the photodetector. 1. An optical recording and reproducing apparatus comprising: a detection means for detecting a mark signal; and a discrimination means for discriminating between the front and back sides of an optical disc based on the front and back discrimination mark signals detected by the detection means. (2) Front and back discrimination In the track area, two front and back discrimination marks, a reference mark and a comparison mark, are formed at positions that are not symmetrical with respect to the center of the disc, and the discrimination means detects the reference mark and the comparison mark. 2. The optical recording/reproducing apparatus according to claim 1, wherein front and back sides are determined based on a time difference. (3) There are independent front/back discrimination track areas on the front and back sides, a reference mark is formed only in one front/back discrimination track area, and the discrimination means distinguishes between the front and back depending on whether or not the reference mark is detected. An optical recording/reproducing apparatus according to claim 1.