JPH0447375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an information recording and reproducing apparatus that records and reproduces information using an optical recording medium that can record information using optical energy. Note that in the present invention, recording and reproduction means both recording and reproduction.

Conventionally, microfilm, video disc, digital audio disc, DRAW system, etc. have been known as applications of optical recording methods. In recent years, the application of this technology to information file systems has been attracting particular attention, in which laser light is focused on a minute spot on an optical recording medium, and a thin metal film such as Te.Bi is evaporated to form a pit (hole). , a draw system using optical recording media.

A feature of the draw system is that it allows the user to record and even record additionally (ADD/ON). Furthermore, although the information recorded on the optical recording medium by forming bits cannot be erased and cannot be repeatedly recorded, it is resistant to changes over time and is most suitable for long-term storage.

On the other hand, recently, low oxidation Te, MnBi,
GdTbFe・GdCO・GdFeCO・GdDyFe・
Research and development of erasable optical recording media, such as magneto-optical materials such as GdTbFeCO, have been announced one after another. However, while erasable optical recording media have the advantage of being capable of repeated recording, they still have the disadvantage of being unstable in recorded information when stored for a long period of time, ie, being susceptible to changes over time.

Therefore, by taking advantage of the merits of both optical recording media, non-erasable optical recording media can be used as information files for long-term storage, while erasable recording media can be used for short-term storage.
Alternatively, it is desirable to use it as a temporary information file. Application examples of long-term storage information files are in fields where conventional microfilms have been used, and application examples of short-term or temporary information files include buffer memories for printers and the like.

However, since these optical recording media generally have different recording sensitivities, there is no example in which optical recording media with different characteristics can be recorded and reproduced using the same device, and information that takes advantage of the advantages of optical recording media with different characteristics is not available. The files could not be processed on the same device.

An object of the present invention is to solve the above-mentioned problems and provide an information recording and reproducing apparatus that can record and reproduce information on any optical recording medium with different characteristics.

The above object of the present invention is to provide an information recording and reproducing apparatus that selectively records information on an optical recording medium and reproduces information from the medium by irradiating the optical recording medium with a light beam. Information shall be recorded and reproduced using multiple types of optical recording media with different recording sensitivities, and the recording device shall include:
a control circuit for presetting the optimum value of the light beam intensity in two stages of recording mode and playback mode for each type of medium; a determining means for determining the type of optical recording medium loaded in the apparatus; mode selection means for selecting recording or playback by an operation of the control circuit, and the control circuit determines one of the optimum values based on the result of determination by the determination means and the result of selection by the mode selection means. However, this is achieved by a configuration in which the intensity of the light beam irradiated onto the medium is controlled to a determined optimum value.

The present invention will be explained in detail below based on illustrated embodiments.

1 to 3 show the present invention and one embodiment,
FIG. 1 is an overall schematic diagram. 1 is a cover,
The setting of the optical recording medium 2 is performed by setting the cover 1, for example.
This is done by opening and closing. 3 is a light projector such as a light emitting diode, and 4 is a light receiver for receiving reflected light, which is attached to the back side of the cover 1 together with the projector 3. A motor 5 rotates the optical recording medium 2 at a predetermined number of rotations. Reference numeral 6 denotes a head section in which a lens 7 for connecting a minute spot on the surface of the optical recording medium 2, a light source to be described later, an astigmatism optical system, a 4-split photodetector, etc. are arranged. It is moved by a motor 9 and a pulley mechanism 10. Reference numeral 11 denotes an operation button for switching between recording and reproduction.

FIG. 2 shows the optical system within the head section 6. As shown in FIG. 12
is an actuator equipped with a mechanism that performs automatic focus control by moving the lens 7 in the optical axis direction, and a mechanism that performs tracking and time axis correction by moving the lens 7 back and forth and left and right. Reference numeral 13 denotes a light source such as a semiconductor laser, whose beam is made into a desired luminous flux distribution by a collimation lens 14, and then sent to a beam splitter 15.
, and is reflected and deflected by a total reflection mirror 16. 1
7 is a polarizing plate through which the light beam split by the beam splitter 15 passes; 18 is an astigmatism optical system composed of, for example, a spherical lens and a cylindrical lens; 1;
9 is a 4-split photodetector.

FIG. 3 is a block diagram showing the signal processing system.
20 is a comparator that compares a preset reference voltage with the level from the light receiver 4; 21 is a switch that is linked to the operation button 11; for example, it is turned on when recording is selected, and it is turned on when playback is selected; It turns off. 22 is a NAND gate that outputs a high-level signal when the switch 21 is turned on; 23 is a decoder; for example, when a high-level signal is input from the comparator 20, a non-erasable recording medium is input; a low-level signal is input. Accordingly, it is processed as an erasable recording medium, and when a high level signal is input from the NAND gate 22, it is recorded, and when a low level signal is input, it is processed as a playback medium. 24 is
This is a control circuit that controls the current flowing through the light source 13 according to the output from the decoder 23.

In the embodiment shown in FIGS. 1 to 3, the optical recording medium 2
Whether it is an optical disk or a magneto-optical disk, it is used for recording and reproducing. Before explaining its operation, let us explain the recording and reproducing principles of optical disks and magneto-optical disks.
This will be explained using figures. 2a is an optical disk, 2b is a magneto-optical disk, 25 is a pit formed on the surface of the optical disk 2a, and ±θ _K is a Kerr rotation angle.

Recording on the optical disk 2a shown in figure a is performed using the light source 1.
This is done by melting the metal thin film, etc. on the surface of the optical disk 2a by the photothermal energy from 3 to form pits 25 or convex portions. Although many of these optical disks 2a are resistant to aging and can withstand long-term storage, they have the disadvantage that they cannot be erased. The principle of reproduction from the optical disc 2a is performed by utilizing the interference of reflected light from the pit 25 and the surface around the pit 25 of the optical disc 2a. Even if this reflected light does not pass through the polarizing plate 17 (Fig. 2), it is modulated in brightness and darkness depending on the presence or absence of the bit 25, so the polarized light transmission axis of the polarizing plate 17 is set at the dotted line position shown in Fig. b. Even though there is a disadvantage that the amount of light passing through the polarizing plate 17 is reduced, there is a component passing through, so it can be reproduced. In addition, if the reflected light wavelength is λ, pit 25
When the depth is λ/4, the interference phenomenon between both reflected lights occurs most strongly, and the contrast of the reproduced signal becomes better.

To record on the magneto-optical disk 2b made of GdTbFe, GdCO, GdDyCO, MnBi, etc., as shown in figure c, a unidirectional magnetic field is applied to the magneto-optical disk 2b from the outside in advance to align the magnetization direction, and photothermal energy is applied to magnetize the disk. A reversal occurs locally, and the direction of magnetization (c
This is done by changing the top and bottom directions shown in the figure. Furthermore, when a light flux with a uniform polarization plane is applied to the magneto-optical disk 2b recorded in this manner, reflected light with a rotated polarization plane is obtained due to the magneto-optical effect. This phenomenon is the well-known Kerr effect, and the rotation angle of the polarization plane of light is called the Kerr rotation angle θ _K.
The rotation angle of the polarization plane is reversed depending on the direction of magnetization, and the Kerr rotation angle −θ _K and Kerr rotation angle +
θ _K. For example, if the polarized light transmission axis of the polarizing plate 17 is set to the position indicated by the dotted line in figure d, the polarizing plate 17
The components of the light flux passing through the polarization plane are different between the Kerr rotation angle +θ _K and the Kerr rotation angle −θ _K , and the difference results in a change in light intensity, which is read out by the 4-split photodetector 19 as a reproduction signal. I can do it.

In this way, when recording and reproducing information on two types of optical recording media 2 (optical disk and magneto-optical disk), photothermal energy can record information on each optical recording medium 2 or reproduce information from the optical recording medium 2. It can be seen that this can be done by increasing or decreasing the output intensity of the light source 13 so as to obtain the energy. These two typical types of optical recording media 2 usually have different reflectances. Therefore, by measuring the difference in reflectance, the type can be determined, and the output intensity of the light source 13 can be set to be suitable for each type.
Even if the reflectance of the optical recording medium 2 is the same, if the substrate of the optical recording medium 2 is transparent, by coating the surface of the optical recording medium 2 with a dielectric film or the like, the difference in the reflectance of the optical recording medium 2 can be directly adjusted. If the substrate of the optical recording medium 2 is opaque, it can be determined by pasting labels with different reflectances depending on the type on the back side of the substrate of the optical recording medium 2 (the side opposite to the medium surface). I can do it.

Next, the operation will be explained. Open the cover 1, set the optical recording medium 2, and close it. Next, manually select recording or playback using the operation button 11. Thereby, light is projected from the light projector 3 onto the optical recording medium 2 by a circuit not shown, and the reflected light is received by the light receiver 4. The output from the light receiver 4 is input to the comparator 20,
is compared with the reference voltage of For example, now receiver 4
When the optical recording medium 2 receives reflected light from the non-erasable optical recording medium 2, the output from the comparator 20 becomes high level and is input to the decoder 23. Further, when recording is selected by the operation button 11, the switch 21 is turned on in conjunction with the operation button 11, and a high level signal is output from the NAND gate 22 to the decoder 23. As a result, in the decoder 23, since the high level signal is input from the comparator 20, it is treated as a non-erasable recording medium, and the high level signal is input from the NAND gate 22, so it is processed and output to the control circuit 24 as recording.

Note that the output from the decoder 23 is () Recording - Non-erasable recording medium () Recording -
There are four cases: erasable recording medium () reproduction - non-erasable recording medium () reproduction - erasable recording medium, but in the control circuit 24 ()
The current flowing to the light source 3 is controlled according to ~(). For example, in the case of a low-sensitivity recording medium (for example ()) in the recording mode, modulation drive is performed with a high current according to the information signal. In the case of playback mode (for example ()), the output is controlled to be below the recording threshold value and the light source 13 continuously emits light.Also, in the recording or playback mode, the high-sensitivity recording medium (for example () or ())
In the case of , the current value mentioned above (for example, (),
(in case of )) control to a lower level. In addition,
The current values for each of these four cases are set in advance to respective optimum values by the control circuit 24.
Therefore, the output intensity and waveform of the light source 13 are controlled by the control circuit 24, and the output intensity and waveform correspond to () to ().

A beam from a light source 13 such as a semiconductor laser is formed into a desired luminous flux distribution by a collimation lens 14, passes through a beam splitter 15, is reflected and deflected by a total reflection mirror 16, and then becomes a minute spot by a lens 7, where it is optically recorded. The light is focused onto medium 2.

The reflected light from the optical recording medium 2 passes through the lens 7 and the total reflection mirror 16 again, and is split by the beam splitter 15. After passing through the deflection plate 17, the divided light flux passes through the astigmatism optical system 18 and enters the four-split photodetector 19. The combination of the astigmatism optical system 18 and the 4-split photodetector 19 is used to obtain an error signal for automatic focus control of the actuator 12, and its principle is already known. Also,
It is also a known technique that with this combination, it is possible to detect tracking errors by utilizing the diffraction phenomenon of the track grooves of the optical recording medium 2. Note that several methods have already been proposed for the actuator 12;
Generally, a device using a voice coil mechanism is used.

According to this embodiment, from the light projector 3 to the optical recording medium 2
The reflected light is received by the light receiver 4, and the decoder 23 and control circuit 24 automatically determine the type of optical recording medium 2 and control the output intensity of the light source 13. Information can be recorded and reproduced on any of the different optical recording media 2.

FIG. 5 shows another embodiment of the invention. 1st, 3rd
Parts that are similar to those in the figures are designated by the same reference numerals. 25 is an analog switch that turns on and off according to the output from the decoder 23, and 26 is a resistor string in which resistance values R ₁ , R ₂ , R ₃ , and _{R 4} of different values are provided in parallel. , R ₂ , R ₃ , and R ₄ are set optimally for the four cases (), (), (), and () described above. 27 is a waveform control circuit.

Next, the operation will be explained. The reflected light from the optical recording medium 2 is received by the light receiver 3, and its output level is output to the comparator 20. The comparator 20 compares the reference voltage with the output level from the light receiver 4. For example, when the light receiver 4 receives reflected light from a non-erasable recording medium, the output from the comparator 20 becomes high level, and the decoder 2
Enter to 3. In addition, by selecting record on the operation button 11, the switch 21 is turned on, and the output from the Nant gate 22 becomes high level and input to the decoder 23 and the waveform control circuit 27. The decoder 23 receives a high level signal (non-erasable recording medium) from the comparator 20.
High level (recording) signals are input from NAND gate 22, so analog switch 2
5, the resistance value R ₁ corresponding to the case () is selected, and the output intensity of the light source 13 is changed.

On the other hand, when a high level (recording) signal is input from the NAND gate 23, the waveform control circuit 27 operates, modulating the current flowing to the light source 13, and creating a waveform suitable for recording on a non-erasable recording medium. shall be.

During playback, resistance value R ₃ is selected and light source 13
The waveform control circuit 27 also causes a certain level of current to flow through the light source 1 to produce a beam of a certain level suitable for reproduction from a non-erasable recording medium.
Generate from 3.

According to this embodiment, the type of optical recording medium 2 is automatically determined by the comparator 20, decoder 23, analog switch 25, resistor array 26, and waveform control circuit 27, and the output intensity and waveform of the light source 13 are controlled. , information can be recorded and reproduced on any of the optical recording media 2 having different characteristics.

FIG. 6 shows another embodiment of the invention. 1st, 5th
Parts that are similar to those in the figures are designated by the same reference numerals. The difference from the embodiment shown in FIG. 5 is the method of controlling the current flowing to the light source 13, in which the combined resistance of the resistor string 30 consisting of resistance values R ₅ , R ₆ , and R ₇ is determined by the combination of switches 28 and 29.
Change R ₀ . That is, when the switches 28 and 29 are set to turn on when a high level signal is output from the comparator 20 and the NAND gate 22, and turn off when a low level signal is output, the combination of the resistor string 30 is set. Resistance value R ₀
(1) 1/R ₀ = 1/R ₅ + 1/R ₆ + 1/R ₇ (2) 1/R ₀ = 1/R ₅ + 1/R ₇ (3) 1/R ₀ = 1/R ₆ +1/R ₇ (4) 1/R ₀ = 1/R ₇ It can take the above four values (1), (2), (3), and (4).
Therefore, four types of current control can be performed, and the output intensity can be adjusted to suit each case.

According to this embodiment, the comparator 20, the waveform control circuit 27, the switches 28 and 29, and the resistor string 30
Since the type of optical recording medium 2 is automatically determined and the output intensity and waveform of the light source 13 are controlled, information can be recorded and reproduced on any of the optical recording media 2 having different characteristics.

In the illustrated embodiment, the projector 3, the receiver 4, the comparator 20, and the decoder 23 correspond to the discrimination means of the present invention, and the operation button 11, the switch 21, and the NAND gate 22 correspond to the mode selection means.
The control circuit 24, the analog switch 25, the resistor string 26, the switches 28, 29, and the resistor string 30 correspond to the control circuit.

In this embodiment, one light source 13 is used, but the invention is not limited to this, and recording and reproduction may be performed by changing the beam intensity using four light sources.

As explained above, according to the present invention, there are two recording modes and two reproduction modes for each type of optical recording medium.
A control circuit for presetting the optimum value of the light beam intensity of each stage, a discrimination means for discriminating the type of optical recording medium loaded in the apparatus, and a mode selection means for selecting recording or reproduction according to a user's operation are provided. , the control circuit determines one of the optimum values based on the determination result of the determination means and the selection result of the mode selection means, and determines the intensity of the light beam irradiated to the medium. Therefore, when recording and reproducing information using multiple types of optical recording media with different recording sensitivities, it is possible to easily realize optimal recording and reproducing. I can do it.

[Brief explanation of drawings]

FIG. 1 is an overall schematic diagram showing an information recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a layout diagram of an optical system in the head section in FIG. 1, and FIG. Block diagram showing the signal processing system,
4a, b, c, and d are diagrams showing the recording and reproducing principle of the information recording and reproducing apparatus, FIG. 5 is a block diagram showing a signal processing system in another embodiment of the present invention, and FIG. 6 is a diagram showing the signal processing system according to another embodiment of the present invention. FIG. 3 is a block diagram showing a signal processing system in another embodiment. 2... Optical recording medium, 3... Emitter, 4... Light receiver, 6... Head section, 7... Lens, 11... Operation button, 13... Light source, 20... Comparator, 21... Switch, 22...Nand Gate,
23... Decoder, 24... Control circuit, 25...
Analog switch, 26... Resistor string, 27... Waveform control circuit, 28, 29... Switch, 30...
Resistance string, R ₁ to R ₇ ...Resistance value.

Claims (1)

[Scope of Claims] 1. An information recording/reproducing device that selectively records information on an optical recording medium and reproduces information from the medium by irradiating the optical recording medium with a light beam, wherein the devices are mutually connected to each other. The apparatus records and reproduces information using multiple types of optical recording media with different recording sensitivities, and the apparatus has two levels of light beam intensity, recording mode and reproduction mode, for each type of medium. The control circuit includes a control circuit for presetting an optimum value, a discrimination means for discriminating the type of optical recording medium filled in the apparatus, and a mode selection means for selecting recording or reproduction according to a user's operation. , one of the optimum values is determined based on the discrimination result of the discrimination means and the selection result of the mode selection means, and the intensity of the light beam irradiated to the medium becomes the determined optimum value. An information recording and reproducing device characterized in that it is controlled as follows.