JPH05250674A - Method and device for optical information recording and reproducing - Google Patents

Abstract

PURPOSE:To speed up changeover of writing of data and reading of control information by increasing a laser beam output to the extent of not receiving the influence of light quantity noises even in the period of either of a recording mode and a reproducing mode. CONSTITUTION:A drive controller 3 drives a semiconductor laser 1 by a current source 5 which generates a DC current of a specified large value by putting a WR/EREN signal at an 'L' state and setting a switch 9 at an open state at the time of the reproduction mode. The quantity of the laser beam is attenuated by a prescribed quantity according to the required light quantity and the surface of an optical disk is irradiated with this light. On the other hand, the WR/EREN signal is put into an 'H' state and the laser 1 is driven by the current sources 5, 7 at the time of the recording mode, by which the quantity of the laser beam for irradiating the surface of the optical disk is controlled according to the required light quantity. Then, the changeover of the data writing to the recording region and the reading of the control information fro the control region is executed at a high speed. In addition, the device constitution is simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing method and apparatus for recording / reproducing data by using a laser beam on an optical recording medium in which pre-format areas and data recording areas are alternately arranged. The present invention relates to a method and apparatus for changing the irradiation light amount level to an optical recording medium in a data recording mode and a data reproducing mode.

[0002]

2. Description of the Related Art In recent years, an optical recording medium such as an optical disk has been developed in response to a demand for increasing the amount of information recorded.
As such an optical disk, there is known an optical disk in which a pre-format area composed 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.

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

[0004]

When the recording mode is set, the light output level of the laser output is switched at high speed as described above, and accordingly, the high frequency current is switched on / off to be superimposed on the drive current. Is also done at high speed. That is, when writing data in the recording area, the high frequency current is turned off because the laser output is in a high output state.
On the other hand, when the control information is read from the preformatted area, the high frequency current is turned on because the laser output is in a low output state.

However, the high-frequency current requires a time of several μsec after the ON / OFF switching until the level stabilizes, and in the case of an optical disc rotating at a high speed, the intermediate area (writing also occurs) corresponding to the time required for the level stabilization. It is necessary to provide an area (where reading is not performed), which causes a problem that the recording capacity is reduced.

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 structure of the device.

The present invention has been made to solve such a problem, and when the recording mode for writing data is set, switching between the writing of data in the recording area and the reading of control information from the control area is performed. It is an object of the present invention to provide an optical information recording / reproducing method and device which can be performed at high speed and can simplify the device configuration.

[0008]

In the optical information recording / reproducing method of the present invention, a control area in which pits carrying control information are arranged and a recording area in which the recording information is written are alternately arranged. The amount of laser light when the laser light is scanned on the optical recording medium to reproduce the record information written in the recording area and the recording mode in which the record information is recorded in this recording area. A large amount of light is output so that the influence of noise is not a problem, and one of the laser beams is output for each mode according to the required amount of light on the optical recording medium in each of the reproduction mode and the recording mode. It is characterized in that a portion is shielded from light by a predetermined amount.

Further, the optical information recording / reproducing apparatus of the present invention is an optical recording medium in which a control area in which pits carrying control information are arranged and a recording area in which the recording information is written are alternately arranged. An optical scanning means for mounting and scanning a laser beam on the optical recording medium, and a laser having a large light amount such that the influence of the laser light amount noise does not pose a problem when recording and reproducing information on the optical recording medium. A laser light source that outputs light, a reproduction mode that reproduces information written in the recording area and a required light amount in each mode of a recording mode that records desired information in the recording area. An optical variable filter that attenuates the light quantity of the laser light by a predetermined amount is provided on the optical path of the laser light between the recording media.

[0010]

According to the above-described optical information recording / reproducing method and apparatus of the present invention, the recording mode is set, that is, the period for writing data in the recording region and the period for reading control information from the control region. Even in
The output from the laser light source is set to a large level so that the influence of light intensity noise does not pose a problem, and it is not necessary to superimpose a high-frequency current on the light source drive current when reading control information as in the conventional case. Therefore, in the recording mode, it is possible to perform high-speed switching between data writing to the recording area and reading control information from the control area without requiring a period for stabilizing the level of the drive current.

Further, not only in the recording mode but also in the reproducing mode, the output from the light source is set to a large level so that the influence of the light amount noise does not pose a problem, and the adjustment of the light amount on the optical recording medium is performed by the optical variable filter. Therefore, the influence of the light amount noise does not increase even if the high frequency current is not superimposed on the light source drive current. Therefore, unlike the prior art, a high frequency signal generator is not required, and the device configuration can be simplified.

[0012]

Embodiments 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 is a semiconductor laser (L
D) 1, a drive controller 3 that outputs a control signal for adjusting the laser light output from the semiconductor laser 1 to control the drive current, and first and first drive currents that drive the drive current from the semiconductor laser 1. 2 current sources 5, 7
A switch (SW) 9 arranged between the semiconductor laser 1 and the second current source 7, and a part of laser light arranged on the optical path between the semiconductor laser 1 and the optical disc. An optical variable filter (not shown) that shields light is provided. The optically variable filter is, for example, EO.
The modulator is composed of a modulator, an AO modulator, etc., and the transmittance of the laser light is changed by the control signal V _F. Further, the drive controller 3 outputs a WRDT signal (write data signal), a PFRD signal (preformat read signal), a WR / EREN signal (write / erase enable signal), a V _PULSE signal (pulse voltage signal), and a V _DC signal. (DC voltage signal) and various control signals such as the V _F signal (filter transmittance control signal) are output. Furthermore, an OR circuit 11 for calculating a logical sum of the WRDT signal and the PFRD signal. And an AN for calculating the logical product of the output signal of the OR circuit 11 and the WR / EREN signal
The D circuit 13 is arranged at a predetermined position.

Next, the operation of this device will be described with reference to FIGS. In FIG. 2, WR /
A graph showing the 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 transmittance of the laser light by the optically variable filter are drawn.

On the other hand, FIG. 3 shows the format of an optical disc on which data is recorded by the above apparatus. That is, 32 sectors 33 of the same size are formed in the circumferential direction on the optical disc 31, and 20000 tracks 35 are formed in a substantially concentric shape. One track 35 in one sector 33 is composed of 43 segments 37, and this one segment is composed of a 2-byte preformatted area 39 and a 16-byte data recording area 41. The pre-formatted area 39 is an area in which concave and convex pits for control are formed in advance in order to stably perform tracking and the like, while the data recording area 41 is an area in which desired data is written by the device.
A header 43 for sector identification is formed in the first segment 37 of each sector 33.

Further, uneven pits 47, 48 and 49 are formed as servo information areas in the first 2 bytes of each segment. This state is shown in FIG.

In FIG. 2, when the WR / EREN signal is in the L state, it is a period (a, c, e) in which the apparatus is set in the reproduction mode, and when it is in the H state, the apparatus is in the H state. Is set to record erase mode (b, d)
When the PFRD signal is in the H state, it indicates that the control information is read from the preformatted area 39.

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

As described above, in the above device, since the laser emission light quantity is increased, the influence of the laser light quantity noise does not pose a problem, and the high frequency signal superimposed on the drive current is not required in the prior art. However, irradiating the optical disc 31 with a laser beam having such a large amount of light causes a change in the recording film of the data recording area 41 in the reproduction mode, so in this reproduction mode, the transmittance of the optically variable filter should be lowered. Therefore, the light amount of the laser beam applied onto the optical disc 31 is reduced. Data reading and control information reading in the reproduction mode are performed by the laser light having a small light amount level.

When the erase mode is set (b), the WR
Since the / EREN signal is in the H state and the WRDT signal (write data) is continuously input, the output from the AND circuit 13 is in the H state. As a result, the switch 9 is closed. Therefore, the semiconductor laser 1 is
It is driven by the first current source 5 and the second current source 7. Due to the drive current generated by the second current source 7, the laser light amount level becomes larger than that at the time of setting the recording mode, and the laser emission light amount level in this erasing mode becomes P _E in FIG. In this erasing mode, it is necessary to increase the light amount of the laser light irradiated onto the optical disc 31, so that the transmittance of the optically variable filter is high.

When the recording mode is set (d), the WR
Since the / EREN signal is in the H state, the above AND circuit 13
Output becomes high when a WRDT signal (write data) is input or when a PFRD signal is input, whereby the switch 9 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 emission light quantity level in this recording mode is as shown by P _W in FIG. The maximum value and the minimum value of this level are determined by the control signals V _DC and V _PULSE input to the two current sources 5 and 7 described above. In this recording mode, the amount of light irradiated onto the optical disc 31 is small during the period in which the control information is read from the preformatted area 39 and large during the period in which data is written in the recording area 41. For this reason, the transmittance of the optically variable filter is low during this control information reading period, while it is high during this data writing period.

The optical information recording / reproducing method and apparatus of the present invention are not limited to those of the above-described embodiment, and various other modifications can be made. Further, although a disk-shaped optical disc is used as the optical recording medium in the above-described embodiments, other forms such as a sheet-shaped one and a card-shaped one can be used.

[0023]

As described above, according to the optical information recording / reproducing method and apparatus of the present invention, the writing and reading of this information is affected by the light quantity noise in both the recording mode and the reproducing mode. By increasing the amount of laser light emitted so as not to receive it, it is not necessary to superimpose a high-frequency signal for noise removal on the drive current of the light source. Therefore, in the reproduction mode, it is possible to perform high-speed switching between the writing of data to the recording area and the reading of control information from the control area, which conventionally takes time to switch ON / OFF of the high-frequency signal. As a result, the problem of the prior art that the recording capacity is reduced by providing the intermediate area between the control area and the recording area for stabilizing the level of the drive current does not occur at all.

Further, since the high frequency signal generator is not required, the device structure can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing an optical information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the device shown in FIG.

FIG. 3 is a schematic diagram showing a format of an optical disc on which information is recorded / reproduced by the apparatus shown in FIG.

[Explanation 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

Claims (2)

[Claims] 1. A laser beam is scanned on an optical recording medium in which a control area in which pits carrying control information are arranged and a recording area in which recording information is written are alternately arranged, and the recording area is formed in the recording area. Laser light having a large amount of light to such an extent that the influence of the laser light amount noise does not pose a problem regardless of whether the reproduction mode for reproducing the recorded information being written or the recording mode for recording the recording information in this recording area is set. Is output, and the light amount of the laser light is attenuated by a predetermined amount for each mode according to the required light amount on the optical recording medium in each of the reproduction mode and the recording mode. Optical information recording / reproducing method. 2. An optical recording medium in which a control area formed by arranging pits carrying control information and a recording area in which recording information is written are alternately arranged, and a laser is placed on the optical recording medium. An optical scanning means for scanning light, a laser light source for outputting a laser light having a large light quantity such that the influence of laser light quantity noise does not matter when recording and reproducing information on the optical recording medium, and the recording area Depending on the required light quantity in each of the reproduction mode for reproducing the information written in the recording area and the recording mode for recording the desired information in this recording area, the light of the laser light between the laser light source and the optical recording medium An optical information recording / reproducing apparatus comprising an optically variable filter for attenuating the amount of laser light on the road.