JPH09282783A - Optical recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform recording and reproducing under the most preferable condition by discriminating plural kinds of optical recording media having different independencies on wavelengths in reflectance. SOLUTION: The device is composed of an optical recording medium 1, light emitting sources 2 and 3 having their different wavelengths from each other, positioned at a fixed distance from the optical recording medium 1, respectively, photodetectors 4 and 5 to receive light reflected by the optical recording medium 1 out of the light emitted from the light emitting sources 2 and 3, a differential amplifier 6 for detecting a difference between outputs of the photodetectors 4 and 5 and a comparator 8 for comparing an output of the differential amplifier 6 with a variable electric potential 7. In this case, prior to recording or reproducing, plural kinds of optical recording media having different independencies on wavelengths in reflectance are discriminated by outputs of the comparator 8, respectively. In accordance with a discriminated signal, laser power, the gain of a control circuit and the revolving speed of a medium, etc., are optimized, thus securing the stability of control operation and preventing a recording film from breaking up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium recording / reproducing apparatus, and an information receiving / reproducing apparatus using the same.
Also, the present invention relates to an apparatus for identifying the type of optical recording medium of electronic components used for these.

[0002]

2. Description of the Related Art In recent years, plural kinds of optical recording media have been developed and used. The compact disc (CD) is a read-only medium, and the CD-R is one of recordable optical recording media. Other optical recording media include DVD
-ROM, writable phase change disk (PCR), DVD-RAM, etc. In addition to these optical disks, magneto-optical recording media are also used.

[0003]

These plural kinds of optical recording media may be used in the same device. For example, a CD-R is a CD-compatible medium that can be played back on a commercially available compact disc player after recording according to a specified standard. However, CD-R has a greater wavelength dependence of reflectance than CD. For this reason, when the wavelength of the laser of the optical head is shortened, the reflectance is lowered, and it is impossible to reproduce under the same conditions as for CD. For example, at a wavelength of 780 nm, the reflectance is about 90% for CD and about 70% for CD-R. However, at a shorter wavelength side, for example, at a wavelength of 650 nm, the reflectance is about 90% for CD, but drops to about 10% for CD-R. In other words, since the CD-R has a high absorptance of light having a wavelength of 650 nm, if the CD-R is reproduced under the same conditions as the CD using this wavelength, the recorded data may be destroyed. Even if the recorded data is not destroyed, the data cannot be read because the reflectance of the CD-R is low.

An object of the present invention is to provide an optical recording / reproducing apparatus which identifies a plurality of types of optical recording media having different wavelength dependence of reflectance and records / reproduces under optimum conditions. is there.

[0005]

In order to solve this problem, an optical recording / reproducing apparatus according to the present invention uses an optical recording medium that uses the wavelength dependence of the reflectance of an optical recording medium before recording or reproducing. Identify the type of recording medium. A first optical recording / reproducing apparatus of the present invention includes a first light emitting source having a first wavelength and a second light emitting source having a second wavelength, which are arranged at a constant distance on an optical recording medium. Detects the difference between the outputs of the first and second light receiving elements and the first and second light receiving elements that receive the light emitted from the light emitting sources of the first wavelength and the second wavelength and reflected by the optical recording medium. The identification means for With this simple structure, the difference in reflectance at different wavelengths causes
The identification means can identify the type of the optical recording medium by utilizing the fact that the outputs of the two light receiving elements are different. Alternatively, the common light receiving element is used, and the identifying means detects the difference between the two outputs of the light receiving elements obtained by sequentially receiving light in synchronization with each other from the first and second light emitting sources. As a result, the first and second light emitting sources emit light when they are different from each other, and the identifying means detects the difference between the two outputs obtained from the light receiving element in synchronization with the emission of the light, and the optical recording medium. Identify the type of. For example, the first light emitting source has a first wavelength of 720 nm or more, and the second light emitting source is
The second wavelength is less than 720 nm. Also, for example, the first
Is the infrared light emitting diode, and the second light emitting source is the red light emitting diode.

A second optical recording / reproducing apparatus of the present invention comprises a first optical head composed of at least a first laser, a first objective lens and a first light receiving element, and at least a first laser. The second optical head includes a second laser having a different wavelength, a second objective lens, and a second light receiving element. This apparatus uses an optical head originally provided in the optical recording / reproducing apparatus for identifying the type of the optical recording medium. Alternatively, one optical head is used, and this optical head is provided with at least a first laser, a second laser having a wavelength different from that of the first laser, an objective lens, a first light receiving element, and a second light receiving element. The discriminating means receives the light emitted from the first laser, transmitted through the first objective lens, reflected by the optical recording medium, and transmitted through the first objective lens again, and the output of the first light receiving element and the second light receiving element. The difference from the output of the second light receiving element that receives the light emitted from the laser, transmitted through the second objective lens, reflected by the optical recording medium, and transmitted again through the second objective lens is detected, and the optical recording medium is detected. Identify the type of.

In a modification, the optical head includes one light receiving element for two wavelengths. That is, the optical head includes at least a first laser, a second laser having a wavelength different from that of the first laser, an objective lens, and a light receiving element that receives light in synchronization with the emitted light of the first laser and the second laser. Composed of. The first and second lasers emit light at different times, and the identification means receives the light emitted from the first laser, transmitted through the objective lens, reflected by the optical recording medium, and transmitted through the objective lens again. The difference between the output of the light receiving element and the output of the light receiving element that receives the light emitted from the second laser, transmitted through the objective lens, reflected by the optical recording medium, and transmitted through the objective lens again is detected, and the optical difference is detected. Identify the type of recording medium.

Preferably, each of the first and second light receiving elements is divided into at least two parts, and the identifying means has a signal formed by a difference between two outputs of the first light receiving element and a second light receiving element. The difference from the signal composed of the difference between the two outputs is detected. Preferably, each of the first and second light receiving elements is divided into at least two, and the identifying means is the second light receiving element of the first light receiving element.
The difference between the signal composed of the sum of the two outputs and the signal composed of the sum of the two outputs of the second light receiving element is detected. Preferably, the first wavelength of the first laser is 780 ± 60 nm and the second wavelength of the second laser is 660 ± 60 nm.

In still another optical recording / reproducing apparatus of the present invention, a laser having at least a first wavelength, an objective lens, a laser beam emitted from the laser, transmitted through the objective lens, reflected by an optical recording medium, and again the objective lens is provided. An optical head composed of a first light receiving element for receiving the transmitted light, a light emitting source (for example, a light emitting diode) having a second wavelength arranged at a constant distance on an optical recording medium, and the light emitting source A second light receiving element for receiving the light emitted and reflected by the optical recording medium. The identification means detects the difference between the outputs of the first and second light receiving elements and identifies the type of the optical recording medium. For example, the first wavelength of the laser is 780 ± 60 nm and the light emitting source is a light emitting diode. Also, for example,
The first wavelength of the laser is 660 ± 60 nm, and the light emitting source is a light emitting diode. Preferably, when receiving the light reception signal in synchronization with the emission of light, the control unit first receives an output signal of a wavelength having a large wavelength dependency of the reflectance of the optical recording medium among the two wavelengths. This makes it possible to speed up the subsequent processing.

From the identification result, the control unit optimizes the recording / reproducing condition in accordance with the difference in reflectance. For example, when recording or reproducing, the upper limit of the laser power of the optical head, the output gain of the light receiving element, the number of rotations when the optical recording medium is an optical disk, etc. are changed and optimized. When recording or reproduction becomes impossible even after optimizing the recording and reproduction conditions, the control unit stops the operation or ejects the optical recording medium to avoid the recording or reproduction operation.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a recording / reproducing system which is a main part of an optical recording / reproducing apparatus of a first embodiment of the present invention. The term "optical recording / reproducing device" means
It also includes a reproduction-only optical reproducing device. The structure shown in FIG. 1 is publicly known, and is common to each embodiment described below. The optical recording medium 1 to be recorded or reproduced is, for example, a CD or a CD-R. In the optical recording / reproducing apparatus shown schematically in FIG.
Is placed on a tray, for example, and is rotated by the motor 10. The optical head 11 emits a laser beam to the optical recording medium 1 and detects the laser beam reflected by the medium 1. The signal detected by the optical head 11 is received by the signal processing unit 12. The reproduction signal is also sent to the focus tracking servo 13 that moves the optical head 11. The focus tracking drive 14 tracks and focuses the optical head 11. The control unit 15 including the central processing unit is the motor 1
0, the signal processing unit 12, the focus tracking servo and the drives 13 and 14 are controlled.

FIG. 2 shows a part of the optical recording / reproducing apparatus shown in FIG. 1 for identifying the type of the optical recording medium. Before recording or reproducing, the type of magneto-optical recording medium is identified. In each embodiment described below, a CD and a CD-R will be described as examples of the optical recording medium 1 to be identified.
The parts shown in FIG. 1 are not shown for simplicity. The light emitting sources 2 and 3 having different wavelengths are the optical recording medium 1.
Are placed at a fixed distance. For example, the light emitting source 2 is an infrared light emitting diode (LED), and the light emitting source 3 is a red light emitting diode. The light receiving elements 4 and 5 are the light emitting source 2,
The light emitted from 3 and reflected by the optical recording medium 1 is received. The light emitting sources 2, 3 and the light receiving elements 4, 5 are suitable for the optical recording medium 1 so that the light emitted by the light emitting sources 2, 3 and reflected by the optical recording medium 1 can be received by the light receiving elements 4, 5, respectively. It is installed at various positions. It is desirable that the light receiving elements 4 and 5 are installed so that the signals obtained from them are maximized. These components 2 to 5 are attached to, for example, a tray containing an optical recording medium. The light emission sources 2 and 3 have power and power so as not to destroy the recording surface of the optical recording medium to be identified.
It is necessary to set the optical system. The differential amplifier (op amp) 6 detects the difference between the outputs of the light receiving elements 4 and 5. The comparator 8 compares the output of the differential amplifier 6 and the variable potential 7. In this way, prior to recording or reproduction, the output of the comparator 8 identifies the types of a plurality of optical recording media having different wavelength dependences of reflectance. Since two light emission sources are used for identifying the optical recording medium 1, the variable potential 7 for identification has a greater degree of freedom and a larger margin for detection than that for identification by a single light source described later. Also, 2 which will be described later
Compared to the case of making a determination using one light emitting source and one light receiving element, a switching circuit or a switch, and a circuit that holds the output of the light receiving element when two light emitting sources emit light at different times Since it is not necessary, the circuit configuration is simple. Further, since the two light emitting sources are made to emit light at the same time and the outputs of the two light receiving elements can be directly compared with each other, the discrimination speed is high. In addition, if the optical recording medium is installed on a tray or the like, it is possible to make a determination immediately on the spot placed on the tray. It is not necessary to wait until the state (in a general optical disk drive, loading of the tray, chucking of the disk, and start of rotation of the disk motor) is possible, and the determination speed is fast.

Here, a CD and a CD-R will be described as examples of the optical recording medium 1 to be identified. The CD-R, which is one of the optical recording media, is
It is a CD compatible medium that can be played on a CD player, and it is indistinguishable between a CD and a CD-R. However, CD-R
Uses an organic material on the recording surface, and the reflectance for light near 780 nm is close to 70%, while the reflectance for light near 650 nm is about 10%, which has little wavelength dependence. However, it is about 35%, and the reflectance has a large wavelength dependency. FIG. 3 shows a graph of reflectance and absorptance of CD-R.
On the other hand, the CD uses aluminum for the recording surface, and it is 780nm, 680
Both of the reflectances in the vicinity of nm are about 90%, and the wavelength dependence is small. Therefore, in order to distinguish between CD and CD-R, if the wavelength of the light emitting source 2 is 650 nm and the wavelength of the light emitting source 3 is 780 nm, the output of the light receiving element 5 does not change much between CD and CD-R. , The output of the light-receiving element 4 in the case of CD-R is 1/2 that in the case of CD
To about 1/10, a big difference appears. For this reason,
If the output of the differential amplifier 6 that takes the differential of the outputs of the light receiving elements 4 and 5 and the variable potential 7 are compared by the comparator 8 and binary control is performed, CD and CD-R can be distinguished. When discriminating between CD and CD-R in the discrimination circuit of FIG. 2, if the variable potential 7 is set at approximately the midpoint of the potentials appearing in the differential amplifier 6, if the output of the comparator 8 is positive, then CD- R, if negative
It can be identified as a CD. In the above example, the light emitting sources 2 and 3 having different wavelengths are used, but the light emitting source may be one white light and optical filters having different characteristics may be inserted into the light receiving surfaces of the first and second light receiving elements. Similar effects can be obtained.

FIG. 4 shows a portion relating to the identification of the optical recording medium of the optical recording / reproducing apparatus of the second embodiment of the present invention. This device corresponds to the device shown in FIG. 2 from which the light receiving element 5 is omitted, and realizes an equivalent function. The light emitting sources 102 and 103 having different wavelengths are arranged at a fixed distance on the optical recording medium 1. The light emitting sources 102 and 103 emit light when different from each other. The light receiving element 104 receives the light emitted from the light emitting sources 102 and 103 and reflected by the optical recording medium 1 in synchronization with the light emitted from the light emitting sources 102 and 103. As the light receiving element 104, it is preferable to select a light emitting element having a small wavelength dependence at the wavelengths of the light emitting sources 102 and 103. The output of the light receiving element 104 is processed by the control unit 15 in order to identify the type of the optical recording medium. 2 and 4, light sources having different wavelengths are used. For example, the light wavelengths of the first light emitting sources 2 and 102 are 720 nm or more, and the light wavelengths of the second light emitting sources 3 and 103 are less than 720 nm. Is.

FIG. 5 shows a processing flow of the control unit 15. First, the first light emitting source 102 is driven to emit light, and the light receiving element 1 for the light emitted from the first light emitting source 102.
The output of 04 is received and stored (step S10). Next, the second light source 103 is driven to emit light, and
The output of the light receiving element 104 for the light of longer wavelength from the light emitting source 103 is received (step S12). And
The difference between both outputs is calculated (step S14) and compared with a reference value to identify the type of the optical recording medium (step S1).
6). The identification of the type of the optical recording medium described here is applicable not only to this embodiment but also to other embodiments. In addition, preferably, when receiving the light reception signal in synchronization with the emission of light, the control unit first receives an output signal of a wavelength having a large wavelength dependency of the reflectance of the optical recording medium among the two wavelengths. . As a result, the subsequent type identification processing can be speeded up. After identifying the plurality of types of optical recording media having different wavelength dependences of reflectance as described above, the control unit 15 responds to the difference in reflectance and determines the optimum condition for each of the identified optical recording media. Set to record and play. The operation after this identification is common to each embodiment, and will be described later.

In a modified example (not shown), the output of the light receiving element is sent to the differential amplifier as shown in FIG. 2 via the changeover switch, and the difference between the two outputs of the light receiving element 104 is detected, A comparator compares the output of the differential amplifier with the variable potential to identify the type of optical recording medium. While the first light emitting source 102 is emitting light, the second light emitting source 103 is off, and the changeover switch is connected to the positive input terminal of the differential amplifier. While the second light source 103 is emitting light, the first light source 102 is off and the changeover switch is connected to the negative input terminal of the differential amplifier. In this way, the switches are switched in synchronization with the light emission of the light emission sources 102 and 103. A holding circuit for holding data is added between the switch and the differential amplifier. In this way, the light emitted from the light emitting sources 102 and 103 and reflected by the optical recording medium 1 is received by the light receiving element 104 alone with a time shift, and the output of the differential amplifier is captured and compared.

FIG. 6 schematically shows a part of an optical recording / reproducing apparatus according to a third embodiment of the present invention. This device is shown in FIG.
This device corresponds to a device obtained by omitting the light emitting source 3 and the light receiving element 5 from the above device. The light emitting source 202 is arranged on the optical recording medium 1 at a constant distance. The light receiving element 204 receives the light emitted from the light emitting source 202 and reflected by the optical recording medium 1. Comparator 2
08 detects the difference between the output of the light receiving element 204 and the variable potential 207. In this way, the output of the single light receiving element 204 is directly compared with the variable potential 207 by the comparator 208. CD and CD
When comparing -R, the light emission source 202 is, for example, 660
A wavelength such as ± 60 nm that greatly differs in reflectance of the optical recording medium to be compared may be selected and used.

FIG. 7 schematically shows a part of an optical recording / reproducing apparatus according to a fourth embodiment of the present invention. This device uses two optical heads as light sources of light having different wavelengths. First
The optical head 591 of at least the first laser 591
1, first objective lens 5921 and first light receiving element 5931
The second optical head 592 includes at least a second laser 5912, a second objective lens 5922, and a second optical lens 5922.
It is composed of a light receiving element 5932. Differential amplifier 506
Is emitted from the first laser 5911 and the objective lens 592
1 and then reflected by the optical recording medium 1 and again the objective lens 5
The output of the first light receiving element 5931 that receives the light that has passed through 921 and the objective lens 5 that emits from the second laser 5912.
A second light receiving element 593 that receives the light that passes through 922, is reflected by the optical recording medium 1, and is transmitted through the objective lens 5922 again.
Amplify the difference between the two outputs. Comparator 508 compares the output of differential amplifier 506 with variable potential 307. Prior to recording or reproduction, the output of the comparator 508 identifies the types of a plurality of optical recording media having different wavelength dependence of reflectance. Since the two types of optical heads 591 and 592 are used, it is possible to completely cope with recording or reproduction with respect to two or more types of optical recording media having wavelength dependence. Further, since the optical head can also serve as the optical head provided in the optical recording / reproducing apparatus, there is no mechanical component to be newly added and the introduction is easy. (This point is also common to the embodiments using an optical head described later.) To distinguish between CD and CD-R, for example, lasers of 650 nm and 780 nm may be used. Since there is no difference in reflectance between CD at 650 nm and 780 nm, and a large difference in reflectance between CD-R at 650 nm and 780 nm, both can be easily distinguished.

FIG. 8 shows a part of an optical recording / reproducing apparatus according to the fifth embodiment of the present invention. In this device, one optical head is used as a light source of light having different wavelengths so as to share the objective lens, and the optical head is simplified and downsized. The optical head 690 has at least the first laser 691.
1, a second laser 6912, an objective lens 692, a first light receiving element 6931 and a second light receiving element 6932. The wavelengths of the first laser 6911 and the second laser 6912 are different from each other. The differential amplifier 606 outputs the output of the first light receiving element 6931 that receives the light emitted from the first laser 6911, transmitted through the objective lens 692, reflected by the optical recording medium 1 and transmitted through the objective lens 692 again, and the second laser. The difference from the output of the second light receiving element 6932 that receives the light emitted from 6912, transmitted through the objective lens 692, reflected by the optical recording medium 1 and transmitted through the objective lens 692 again is amplified. Comparator 608 compares the output of differential amplifier 606 with variable potential 607. The identification operation is basically the same as that of the device shown in FIG.

FIG. 9 shows a portion relating to the identification of the optical recording medium of the optical recording / reproducing apparatus of the sixth embodiment of the present invention. This device omits one light receiving element from the device shown in FIG. 8 and realizes an equivalent function. The optical head 790 includes at least a first laser 7911, a second laser 7912,
It is composed of an objective lens 792 and a light receiving element 793.
The wavelengths of the first laser 7911 and the second laser 7912 are different from each other. The light receiving element 793 is a laser 7911,
The light emitted from 7912 and reflected by the optical recording medium 1 is received in synchronization with the emitted light of the lasers 7911 and 7912. Similar to the embodiment shown in FIG. 4, the output of the light receiving element 793 is output to the control unit 15 in order to identify the type of the optical recording medium. The operation of the control unit 15 is substantially the same as that shown in FIG.

In the embodiment shown in FIGS. 7 to 9, when the output power of the laser for identifying the type of the optical recording medium may damage the recording surface of the optical recording medium 1 to be identified, It must be set weak enough not to damage the recording surface. Compared to the device shown in FIGS. 2 to 5, the laser and the light receiving element in the optical head, which are essential components in the optical recording / reproducing device, can be used, and there is no new mechanical component added. Easy to introduce.

The output signal of the light receiving element will be described.
Light receiving elements 5931, 5932, 6931 in the optical head,
6932 may be divided into at least two, and the focus error signal may be generated from a combination of two outputs (for example, a combination of two outputs in the case of two divisions). FIG.
Shows an S-shaped waveform 10 appearing in the focus error (FE) signal when the operation of pulling the focus is performed. The horizontal axis represents the distance between the optical head and the optical recording medium 1. The peak level value of this S-shaped waveform 10 is the variable potential (reference value)
The type of the optical recording medium may be identified by comparing with. This identification method has an advantage that the type can be identified even for an optical recording medium whose focus cannot be drawn for some reason such as a scratch on the surface of the optical recording medium. FIG.
In the case of the light receiving element 593 of 0, signals using two wavelengths are output at different times, but a focus error signal (FE) is similarly generated from a combination of these signals.

Similarly, a light receiving element 593 in the optical head is provided.
1, 5932, 6931, 6932 are divided into at least two, and a focus sum signal is generated from a combination of these outputs (for example, a combination of two outputs in the case of two divisions). FIG. 11 shows a waveform 11 appearing in the focus sum signal (FS) when the focus pull-in operation is performed. The horizontal axis represents the distance between the optical head and the optical recording medium 1. The value of the peak level of this waveform 11 is the variable potential
The type of the optical recording medium may be identified by comparison with the (reference value). There are the same advantages as when the S-shaped waveform 10 is used.
In the case of the light receiving element 593 of FIG. 10, signals using two wavelengths are output at different times, but a focus sum (FS) signal is similarly created from the combination of these signals.

FIG. 12 schematically shows a part of an optical recording / reproducing apparatus according to the seventh embodiment of the present invention. Similar to the device shown in FIG. 6, the type of the optical recording medium 1 is identified by the light of one wavelength. The optical head 390 has at least the laser 3
91, an objective lens 392, and a light receiving element 393. The light receiving element 393 receives the light emitted from the laser 391, transmitted through the objective lens 392, reflected by the optical recording medium 1, and transmitted through the objective lens 392 again. . Comparator 3
08 indicates the output of the single light receiving element 393 as a variable potential 307.
And the type of the optical recording medium 1 is identified. CD
In the case of comparing the CD-R with the CD-R, the wavelength of the laser 391 may be selected such that the reflectance of the optical recording medium 1 to be compared greatly differs, for example, 660 ± 60 nm.

FIG. 13 schematically shows a part of an optical recording / reproducing apparatus according to an eighth embodiment of the present invention. This device uses an optical head 490 instead of the light emitting source 3 and the light receiving element 5 of FIG. The optical head 490 includes at least a laser 491, an objective lens 492, and a light receiving element 493.
Consists of The light receiving element 493 receives the light emitted from the laser 491, transmitted through the objective lens 492, reflected by the optical recording medium 1, and transmitted through the objective lens 492 again.
On the other hand, the light emitting source 402 is arranged at a fixed distance on the optical recording medium 1, and the light receiving element 493 receives the light emitted from the light emitting source 402 and reflected by the optical recording medium 1. The differential amplifier 406 detects the difference between the outputs of the light receiving element 493 and the light receiving element 404, and the comparator 408 compares the output of the differential amplifier 406 with the variable potential 407. Prior to recording / reproducing, the type of the optical recording medium is identified by the output of the comparator 408. Since this apparatus uses the optical head 490, the number of constituent parts is reduced, and the optical recording medium 1 can be recognized even if the focus is not drawn. It also has the advantage that the variable potential 7 has a high degree of freedom and a wide margin for detection.

For example, the wavelength of the laser 491 is 780.
± 60 nm, and the light emission source 402 is an LED of other wavelengths. The wavelength of the laser 491 is 660 ±
The emission source 402 has a wavelength of 60 nm and the other wavelengths are LE.
It is D.

Identification of Optical Recording Medium 1 CD and CD-R
However, it is possible to identify other optical recording media as well as CDs and CD-Rs as long as they are optical recording media having different reflectances at a certain wavelength. . The following can be considered for identifying three or more types of optical recording media. For example, when the reflectances of the three types of optical recording media have sufficient variations at certain wavelengths, as shown in FIG. 14, the comparator 8 shown in FIG.
The second comparator 81 is connected in parallel to the
If the electric potentials of 71 and 71 are set appropriately, the two comparators 8 and 8
The optical recording medium can be identified from the output of 1.
The potentials of the variable potentials 7 and 71 are set to V1, V2, and V3 in descending order of the output voltages that appear in the differential amplifier 6 when observing three types of optical recording media. The intermediate potential and the variable potential 71 may be set near the intermediate potential between V2 and V3. If there are more than three types, a comparator and a variable potential may be added in the same manner. This can be realized in other embodiments as well. Further, when identifying three or more types, there is no difference in reflectance at a single wavelength, but when it is possible to identify by using other wavelengths at the same time, a plurality of identifying devices of the above-described embodiments can be combined and realized.

When the type of the optical recording medium is identified, the recording / reproducing conditions of the optical recording / reproducing apparatus are controlled for stabilization in accordance with the identification. This control is included in the flow of the controller 15 in FIG. Hereinafter, this control will be described. In this flow, the optical recording / reproducing apparatus is controlled to stabilize recording and reproduction of the optical recording medium having wavelength dependence, if necessary, in accordance with the identified type of the optical recording medium ( Step S18). For example, the output power of the semiconductor laser in the optical head 11, the gain of the light receiving element in the optical head, and the rotation speed of the optical recording medium are changed and optimized according to the type of the optical recording medium. If recording or reproduction is impossible due to this change, the operation of the device is stopped or the optical recording medium is ejected in order to prevent the recording surface of the optical recording medium from being destroyed (step S20). .

To explain further, for example, the upper limit of the laser power of the optical head is changed and optimized depending on the type of the optical recording medium. Generally, when the power of the laser is increased during recording or reproduction, the emitted laser beam is reflected by the optical recording medium and the amount of light received by the light receiving element increases. However, depending on the type of the optical recording medium, if the power is increased too much, the recording surface of the optical recording medium will be destroyed. Therefore, the upper limit of the laser power of the optical head is changed and optimized depending on the identified optical recording medium so that an appropriate signal can be obtained in the light receiving element. In this way, the destruction of the recording surface of the optical recording medium having the reflectance with wavelength dependence is prevented.

Further, the gain of the output from the light receiving element is changed and optimized. The magnitude of the signal obtained by the light receiving element is
It varies depending on the type of optical recording medium. The signal is made available by changing the gain of the signal obtained there. In this way, a plurality of optical recording media having different reflectance wavelength dependences are stably recorded and reproduced.

When the optical recording medium is an optical disc, the rotation speed of the optical disc is changed and optimized depending on the type of the optical disc. This is because, for example, when reproducing an optical disc having a low reflectance, a sufficient signal cannot be obtained in the light receiving element unless the laser power of the optical head is increased. However, when there is a possibility that the recording surface of the optical disk will be destroyed by increasing the power of the laser, the time during which the laser is irradiated on the recording surface of the optical disk is reduced by increasing the rotation speed of the optical disk, and the recording surface is destroyed. Can be prevented. Further, by slowing the rotation of the optical disc with a weak laser power that does not destroy the recording surface of the optical disc, noise due to the rotation is reduced and recording or reproduction is possible. Thus, the recording surface of the optical recording medium having the reflectance with wavelength dependence is prevented from being destroyed, and a plurality of optical disks having different reflectance with wavelength dependence are stably recorded and reproduced.

Finally, when it is judged that the optical recording medium cannot be recorded or reproduced by using the above method, for example, the focus cannot be pulled in, and the recorded information is read even in the test recording. In the case where it cannot be output, the recording or reproducing operation of the optical recording medium is stopped or the recording or reproducing cannot be performed on the optical recording medium. Alternatively, the optical recording medium is ejected from the optical recording / reproducing device. As a result, it is possible to prevent the destruction of the recording surface of the optical recording medium having the reflectance having wavelength dependency, and particularly the reflectance of which is low, and to avoid the worst case of the destruction of the recording medium. The embodiments described above relate to an optical recording / reproducing apparatus, and further, an information receiving / reproducing apparatus using these and an apparatus for identifying the type of an optical recording medium of an electronic component used therefor. Can also be applied to.

[0033]

EFFECTS OF THE INVENTION Prior to recording or reproducing, it is very inexpensive to compare the output using a light emitting source having two different wavelengths and two light receiving elements using the wavelength dependence of the reflectance of an optical recording medium. The type of optical recording medium can be identified with a simple configuration. Further, from the identification result, the upper limit of the laser power of the optical head, the output gain of the light receiving element, and the number of revolutions can be changed and optimized when the optical recording medium is an optical disk during recording or reproduction. When recording or reproduction is impossible even by using the above means, the recording or reproduction operation is avoided by stopping the operation or ejecting the optical recording medium.
Thus, a stable recording / reproducing operation can be realized even on a recording medium having wavelength dependence, and even when recording / reproducing is unstable, it is possible to avoid the worst case of destruction of the recording surface of the recording medium. Greatly effective in terms of important data protection.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a part of an optical recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic view of another portion of the optical recording / reproducing apparatus of the first embodiment of the present invention.

FIG. 3 is a characteristic diagram of an example of reflectance and absorptance of CD-R.

FIG. 4 is a schematic diagram of a part of an optical recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 5 is a flowchart of a control unit.

FIG. 6 is a schematic diagram of a part of an optical recording / reproducing apparatus of a third embodiment of the present invention.

FIG. 7 is a schematic diagram of a part of an optical recording / reproducing device according to a fourth embodiment of the present invention.

FIG. 8 is a schematic diagram of a part of an optical recording / reproducing apparatus of a fifth embodiment of the present invention.

FIG. 9 is a schematic diagram of a part of an optical recording / reproducing apparatus of a sixth embodiment of the present invention.

FIG. 10 is an S-shaped waveform diagram of a focus error signal.

FIG. 11 is a waveform diagram of a focus sum signal.

FIG. 12 is a schematic diagram of a part of an optical recording / reproducing apparatus of a seventh embodiment of the present invention.

FIG. 13 is a schematic diagram of a part of an optical recording / reproducing apparatus of an eighth embodiment of the present invention.

FIG. 14 is a diagram of a connection configuration of a comparator when there are three or more types of optical recording media to be identified.

[Explanation of symbols]

1 optical recording medium, 2 1st light emission source, 3 2nd light emission source, 4 1st light receiving element, 5 2nd light receiving element,
6 differential amplifier, 7 variable potential, 8 comparator,
15 control part, 102 1st light emission source, 103 2nd
Light emitting source, 104 light receiving element, 402 second light emitting source,
404 Second light receiving element, 406 Differential amplifier, 40
8 comparator, 490 optical head, 506 differential amplifier, 507 comparator, 591 first optical head, 59
2 2nd optical head, 606 differential amplifier, 607 comparator, 690 optical head, 790 optical head

Claims (17)

[Claims] 1. A first light emitting source having a first wavelength and a second light emitting source having a second wavelength, which are arranged at a fixed distance on an optical recording medium, and the first wavelength and the second wavelength. A first and a second light receiving element for receiving the light emitted from the light emitting source of the two wavelengths and reflected by the optical recording medium, and an identification means for detecting the difference between the outputs of the first and the second light receiving elements. Then, the optical recording / reproducing apparatus is characterized in that the type of the optical recording medium is identified by the identifying means. 2. A first light emitting source having a first wavelength and a second light emitting source having a second wavelength, which are arranged at a constant distance on an optical recording medium, and any one of the first and second light emitting sources. A light-receiving element that receives the light emitted from the light-emitting source and reflected by the optical recording medium in synchronization with the light emission from either the first or second light-emitting source; and the first and second light-emitting elements. A discrimination means for detecting a difference between two outputs of the light-receiving element obtained by sequentially receiving light in synchronization with each other from the light source, and the first and second light emission sources emit light at different times, and the discrimination means Detects the difference between the two outputs obtained from the light receiving element in synchronization with the emission of light,
An optical recording / reproducing apparatus, characterized in that the type of optical recording medium is identified by the identifying means. 3. The optical recording / reproducing according to claim 1 or 2, further comprising a first light emitting source having a first wavelength of 720 nm or more and a second light emitting source having a second wavelength of less than 720 nm. apparatus. 4. The optical recording / reproducing apparatus according to claim 1, wherein the first light emitting source is an infrared light emitting diode and the second light emitting source is a red light emitting diode. 5. A first optical head comprising at least a first laser, a first objective lens and a first light receiving element, a second laser having a wavelength different from at least the first laser, and a second optical head. A second optical head composed of an objective lens and a second light receiving element, and a first objective lens which is emitted from the first laser, transmitted through the first objective lens, reflected by an optical recording medium, and again. The output of the first light receiving element for receiving the light transmitted through the second laser, the light emitted from the second laser, transmitted through the second objective lens, reflected by the optical recording medium, and transmitted again through the second objective lens. An optical recording / reproducing apparatus comprising: an identifying unit that detects a difference from an output of the second light receiving element that receives light, and the identifying unit identifies the type of the optical recording medium. 6. An optical head comprising at least a first laser, a second laser having a wavelength different from that of the first laser, an objective lens, a first light receiving element and a second light receiving element, and the first laser. The output of the first light receiving element that receives the light emitted from the laser, transmitted through the objective lens, reflected by the optical recording medium, and transmitted through the objective lens again, and the second
The identification means for detecting a difference from the output of the second light receiving element for receiving the light emitted from the laser, transmitted through the objective lens, reflected by the optical recording medium, and transmitted through the objective lens again, An optical recording / reproducing apparatus characterized in that the type of an optical recording medium is identified by an identifying means. 7. From at least a first laser, a second laser having a wavelength different from that of the first laser, an objective lens, and a light receiving element which receives light in synchronization with the emitted light of the first laser and the second laser. An optical head configured, an output of the light receiving element that receives the light emitted from the first laser, transmitted through the objective lens, reflected by an optical recording medium, and transmitted through the objective lens again, and the second laser Has a discriminating means for detecting a difference from the output of the light receiving element which receives the light which has been emitted from the objective lens, transmitted through the objective lens, reflected by the optical recording medium, and transmitted through the objective lens again. An optical recording / reproducing apparatus characterized by identifying the type of a recording medium. 8. The first and second light receiving elements are each divided into at least two parts, and the identifying means includes a signal composed of a difference between two outputs of the first light receiving element and the second light receiving element. 8. The optical recording / reproducing apparatus according to claim 5, wherein the difference between the signal and the signal formed by the difference between the two outputs is detected. 9. The first and second light receiving elements are each divided into at least two parts, and the identifying means includes a signal composed of a sum of two outputs of the first light receiving element and the second light receiving element. 8. The optical recording / reproducing apparatus according to claim 5, wherein a difference from a signal composed of the sum of the two outputs is detected. 10. The first wavelength of the first laser is 780.
± 60 nm, and the second wavelength of the second laser is 660
The optical recording / reproducing apparatus according to any one of claims 6 to 11, wherein the optical recording / reproducing apparatus has a thickness of ± 60 nm. 11. A laser having at least a first wavelength, an objective lens, and a first light receiving unit that receives light emitted from the laser, transmitted through the objective lens, reflected by an optical recording medium, and transmitted through the objective lens again. An optical head composed of elements, a light emitting source having a second wavelength and arranged at a fixed distance on an optical recording medium, and a second light receiving source for emitting light emitted from the light emitting source and reflected by the optical recording medium Optical recording / reproducing apparatus, which has a light receiving element and an identifying means for detecting a difference between outputs of the first and second light receiving elements, and the identifying means identifies the type of the optical recording medium. . 12. The first wavelength of the laser is 780 ± 60 nm
12. The optical recording / reproducing apparatus according to claim 11, wherein the light emitting source is a light emitting diode. 13. The first wavelength of the laser is 660 ± 60 nm.
12. The optical recording / reproducing apparatus according to claim 11, wherein the light emitting source is a light emitting diode. 14. The control unit first receives an output signal of a shorter wavelength of the two wavelengths than the wavelength of which the wavelength dependency of the reflectance of the optical recording medium is large. The optical recording / reproducing apparatus according to claim 7. 15. A control unit for optimizing recording / reproducing conditions according to the type of the optical recording medium identified by the identifying means, as claimed in any one of claims 1 to 14. An optical recording / reproducing apparatus as described in. 16. The optical recording / reproducing apparatus according to claim 15, wherein the recording / reproducing operation is stopped when recording or reproduction becomes impossible even if the control section optimizes the recording / reproducing conditions. 17. The optical recording / reproducing apparatus according to claim 15, wherein the optical recording medium is ejected when recording or reproduction becomes impossible even if the control section optimizes the recording / reproducing conditions.