JPH04121030U - Optical information recording and reproducing method and device - Google Patents

Description

3. Detailed Description of the Invention (Field of Industrial Application) The present invention provides an optical information recording and reproducing method for recording and reproducing data using a laser beam on an optical recording medium in which preformat areas and data recording areas are arranged alternately. The present invention relates to a method and apparatus, and more particularly to a method and apparatus for changing the level of the amount of light irradiated onto an optical recording medium between data recording mode and data reproduction mode.

(Prior Art) In recent years, optical recording media such as optical disks have been developed in response to the demand for increasing the amount of information recorded.

As such an optical disk, one in which a preformat area consisting of concave and convex pits used for tracking control and the like and a data recording area for recording data are arranged alternately in the track direction is known.

When reading recorded data written on such an optical disk (hereinafter referred to as playback mode setting), the laser output of the semiconductor laser (hereinafter simply referred to as laser output) is set to a low output state, and the data recording area and The preformat area is read alternately. On the other hand, when writing data to such an optical disc (hereinafter referred to as recording mode setting), writing data to the data recording area and reading control information from the preformat area are performed alternately. In this case, the laser output is set to a high output state, and when reading the control information, the laser output is set to a low output state, so the light intensity level of the laser output is switched at high speed. In this way, in the conventional technology, the laser output is set to a low output state for both reading data from the data recording area and reading control information from the preformat area, which makes the laser output easily affected by noise in the amount of emitted light. The semiconductor laser was driven by superimposing a high frequency signal (several hundred MHz) on the light source drive current.

(Problem to be Solved by the Invention) When setting the recording mode, the light intensity level of the laser output is switched at high speed as described above, and in conjunction with this, the high-frequency current to be superimposed on the drive current is switched on/off. It is also done at high speed. That is, when writing data to the recording area, the laser output is in a high output state, so the high frequency current is turned off, while when reading control information from the preformat area, the laser output is in a low output state. The high frequency current is turned on.

However, after the high-frequency current is switched ON/OFF, it takes several microseconds for the level to stabilize, and on an optical disk that rotates at high speed, the intermediate area (both writing and reading) is Therefore, problems such as a decrease in recording capacity have arisen.

Further, as described above, in order to superimpose the high frequency current on the drive current, a circuit for generating a high frequency signal at a predetermined timing is required, which complicates the configuration of the device.

The present invention has been made to solve such problems, and when setting a recording mode for writing data, switching between writing data to a recording area and reading control information from a control area is performed at high speed. It is an object of the present invention to provide an optical information recording/reproducing method and apparatus that can perform the following operations and simplify the apparatus configuration.

(Means for Solving the Problems) The optical information recording and reproducing method of the present invention includes alternating control areas formed by arranging pits carrying control information and recording areas in which recorded information is written. The amount of laser light will vary in both the playback mode, which scans the laser beam on the optical recording medium and reproduces the recorded information written in the recording area, and the recording mode, which records the recorded information in this recording area. A laser beam having a large amount of light is output so that the influence of noise does not become a problem, and the above-mentioned method is applied for each mode according to the required amount of light on the optical recording medium in each mode of the above-mentioned reproduction mode and the above-mentioned recording mode. It is characterized by blocking a portion of the laser light by a predetermined amount.

Further, the optical information recording/reproducing device of the present invention includes an optical recording medium in which a control area formed by arranging pits carrying control information and a recording area in which recorded information is written are arranged alternately. , an optical scanning means for scanning a laser beam on the optical recording medium, and outputting a laser beam having a large amount of light such that the influence of laser beam amount noise does not become a problem when recording and reproducing information on the optical recording medium. of the laser light source and the optical recording medium according to the required light amount in each mode: a reproduction mode for reproducing information written in the recording area, and a recording mode for recording desired information in this recording area. The present invention is characterized in that an optically variable filter is provided on the optical path of the laser beam between the two to block a portion of the laser beam by a predetermined amount.

(Operation) According to the optical information recording and reproducing method and apparatus of the present invention described above, the period in which the recording mode is set, that is, the period in which data is written to the recording area and the period in which control information is read from the control area. Also, the output from the laser light source is set to a level so large that the influence of light amount noise does not become a problem, and there is no need to superimpose a high-frequency current on the light source drive current when reading control information as in the conventional method. Therefore, in the recording mode, it is possible to switch between writing data to the recording area and reading control information from the control area at high speed without requiring a period for stabilizing the level of the drive current.

In addition, not only in this recording mode but also in playback mode, the output from the light source is set to a level so large that the influence of light intensity noise does not become a problem, and the light intensity on the optical recording medium is adjusted using an optically variable filter. Therefore, even if a high frequency current is not superimposed on the light source drive current, the influence of light amount noise does not increase. Therefore, unlike the prior art, a high frequency signal generator is not required, and the device configuration can be simplified.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a part of an optical information recording/reproducing apparatus according to an embodiment of the present invention. This device includes a semiconductor laser (LD) 1 that irradiates a laser beam onto an optical disk, a drive controller 3 that outputs a control signal to control the drive current to adjust the laser beam output from the semiconductor laser 1, and a drive controller 3 that controls the drive current by controlling the laser beam output from the semiconductor laser 1. first and second current sources 5 and 7 that drive the drive current from the laser 1; a switch (SW) 9 disposed between the semiconductor laser 1 and the second current source 7; and the semiconductor laser an optically variable filter (not shown) disposed on the optical path between 1 and the optical disk to block part of the laser beam;
It is equipped with the following. Note that this optically variable filter is composed of, for example, an EO modulator, an AO modulator, etc., and is adapted to change the transmittance of laser light in accordance with a control signal V _F . Further, from the drive controller 3, the WRDT signal (write data signal), PFRD signal (preformat read signal), W
R/EREN signal (write/erase enable signal)
, V _PULSE signal (pulse voltage signal), V _DC signal (DC voltage signal), and the above V _F signal (filter transmittance control signal). and an OR circuit 11 that calculates the logical sum of the PFRD signal and the above PFRD signal.
and the output signal of this OR circuit 11 and the above WR/E
An AND circuit 13 for calculating the logical product of the REN signals is arranged at a predetermined position.

Next, the operation of this device will be explained using FIGS. 2 and 3. FIG. 2 shows, from the top, a graph showing the WR/EREN signal, a graph showing the PFRD signal, a graph showing the WRDT signal, a graph showing the amount of light emitted from the semiconductor laser 1, and a graph showing the amount of light emitted from the semiconductor laser 1, and the laser beam generated by the optically variable filter. A graph showing the light blocking rate is drawn.

On the other hand, FIG. 3 shows the format of an optical disc on which data is recorded by the above device. That is, this optical disc 31 has 32 discs of the same size in the circumferential direction.
sectors 33 are formed, and 20,000 tracks 35 are formed substantially concentrically. 1
One track 35 in one sector 33 is composed of 43 segments 37, and each segment is composed of a 2-byte preformat area 39 and a 16-byte data recording area 41. The preformat area 39 is an area in which concave and convex pits for control purposes are formed in advance to stably perform tracking, etc., while the data recording area 41 is an area into which desired data is written by the device. Note that the first segment 37 of each sector 33 has a header 43 for sector identification.
is formed.

Further, each servo area 45a, 45b is formed from the preformat area 39 for 16 tracks, and each preformat area 39 is composed of 30 bits. FIG. 3 shows that laser spots 47a and 47b for tracking servo are formed on both sides of the track 35 in this control area 39, and a laser spot 49 for recording and reproducing information is formed on this track 35. There is.

Also, in Figure 2, when the WR/EREN signal is in the L state, it is the period (a, c, e) when the device is set in the playback mode, and when it is in the H state, the device is in the recording mode. This indicates a period (b, d) in which the erasure mode is set, and when the PFRD signal is in the H state, it indicates a period in which control information is read from the preformat area 39.

That is, when the reproduction mode is set (a, c, e), the WR/EREN signal is in the L state, so the output from the AND circuit 13 is in the L state. Therefore, the switch 9 becomes open, and the semiconductor laser 1 is driven by the first current source 5. The value of the DC current generated by the first current source 5 is a constant large value, and the laser emitted light amount level in this reproduction mode is as shown in P _R in FIG. 2.

In this way, in the above device, since the amount of laser emitted light is increased, the effect of laser light amount noise does not become a problem, and the high frequency signal superimposed on the drive current in the conventional technology is not required. However, if the laser beam with such a large amount of light is transmitted to the optical disk 31,
If the laser beam is irradiated on the optical disc 31, the recording film in the data recording area 41 will change in the reproduction mode. The amount of laser light irradiated to the area is reduced. Data reading and control information reading in the reproduction mode is performed using this laser light with a small light intensity level.

In addition, when the erase mode is set (b), WR/E
Since the REN signal is in the H state and the WRDT signal (write data) continues to be input, the AND circuit 13
The output from is in the H state. As a result, the switch 9 is brought into a closed state. Therefore, the semiconductor laser 1 is driven by the first current source 5 and the second current source 7. Due to the driving current generated by the second current source 7, the laser light intensity level becomes higher than that when the recording mode is set, and the laser emission light intensity level in this erasing mode becomes as shown by P _E in FIG. 2. In this erase mode, it is necessary to increase the amount of laser light irradiated onto the optical disc 31, so the transmittance of the optically variable filter is set to be high.

Also, when setting the recording mode (d), WR/E
Since the REN signal is in the H state, the output from the AND circuit 13 is in the H state when the WRDT signal (write data) is input or the PFRD signal is input. repeats opening and closing. Therefore, the semiconductor laser 1 is driven by the first current source 5 and the second current source 7, and the laser emitted light level in this recording mode is as shown by P _W in FIG. 2. The maximum and minimum values of this level are determined by the control signals V _DC and V _PULSE input to the two current sources 5 and 7 mentioned above. Note that the amount of light irradiated onto the optical disc 31 in this recording mode is small during the period when control information is read from the preformat area 39, and large during the period when data is written to the recording area 41. Therefore, the transmittance of the optically variable filter is made low during this control information reading period, while it is made high during this data writing period.

Note that the optical information recording/reproducing method and apparatus of the present invention are not limited to those of the above-mentioned embodiments, and various other changes can be made. Further, in the embodiments described above, a disc-shaped optical disk is used as the optical recording medium, but it is also possible to use other forms such as a sheet-shaped one or a card-shaped one.

(Effects of the Invention) As explained above, according to the optical information recording and reproducing method and apparatus of the present invention, writing and reading of this information is free from the influence of light amount noise in both the recording mode and the reproduction mode. By increasing the amount of laser emitted light to such an extent that it is not affected, it is possible to eliminate the need to superimpose a high frequency signal for noise removal on the drive current of the light source. Therefore, in the playback mode, the conventional high frequency signal ON/Off
Switching between writing data to the recording area and reading control information from the control area, which took time to switch F, can be performed at high speed. This eliminates the problems of the prior art, such as the reduction in recording capacity caused by providing an intermediate area between the control area and the recording area to stabilize the drive current level.

Furthermore, a high-frequency signal generator is not required, and the device configuration can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an optical information recording/reproducing device according to an embodiment of the present invention, FIG. 2 is a timing chart for explaining the operation of the device shown in FIG. 1, and FIG. 3 is similar to FIG. 1 is a schematic diagram showing the format of an optical disc on which information is recorded and reproduced by the apparatus shown in FIG. DESCRIPTION OF SYMBOLS 1... Semiconductor laser, 3... Drive controller, 5... First current source, 7... Second current source, 9... Switch, 31... Optical disk, 35
...Track, 39...Preformat area, 41...Data recording area.

Procedural amendment (method) 3) On page 3, line 1, "Detailed description of the invention" is corrected to "Detailed description of the device."

Claims (2)

[Scope of utility model registration request] 1. A laser beam is scanned on an optical recording medium having a control area formed by arranging pits carrying control information and a recording area in which recording information is written, and a laser beam is scanned onto the recording area. A laser beam with a large enough light intensity that the influence of laser light intensity noise is not a problem, regardless of whether it is set to the playback mode that plays back the recorded information that has been written or the recording mode that records the recorded information in this recording area. is output, and a portion of the laser beam is blocked by a predetermined amount for each mode, depending on the amount of light required on the recording medium in each of the reproduction mode and the recording mode. An optical information recording and reproducing method. 2. An optical recording medium is mounted in which a control area formed by arranging pits carrying control information and a recording area in which recording information is written are arranged alternately, and a laser beam is applied onto the optical recording medium. an optical scanning unit that scans light; a laser light source that outputs a laser beam with a large enough amount of light that the influence of laser light amount noise does not pose a problem when recording and reproducing information on the optical recording medium; and the recording area. The amount of light of the laser beam between the laser light source and the optical recording medium is determined according to the required light amount in each mode: a reproduction mode for reproducing information written in the recording area, and a recording mode for recording desired information in this recording area. An optical information recording/reproducing device comprising an optical variable filter on the road that blocks a predetermined amount of a portion of this laser light.