JP3016259B2 - Optical recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus having means for variably setting the amount of light emitted from a light beam generating means.

[0002]

2. Description of the Related Art In an optical recording / reproducing apparatus, it may be necessary to intentionally change the recording power when using media having different sensitivities, when compensating for the temperature of the medium, or when searching for the optimum recording power.

Usually, a laser diode (hereinafter referred to as an LD) is often used as a light source of an optical head, but the current-light output characteristics of the LD greatly differ depending on each LD. Also, the efficiency of the optical system varies. Therefore, for example, if the recording power is 1
Even when the power is set to 2 mW, the required drive current value differs depending on the individual optical head and is 50 mA or 58 mA.
or mA. Therefore, the current-light output characteristics of the optical head of each device must be measured in advance, and the drive current must be controlled accordingly. This is shown in FIG.

As shown in FIG. 5, the light emission amount of the LD 1 mounted on the optical head 1 with respect to the drive current differs from the light emission amount of the LD 2 mounted on the optical head 2 with respect to the drive current. For example, in order to generate a light emission amount of 12 mW, the drive current of LD1 must be set to 50 mA, whereas the drive current of LD2 must be set to 58 mA.

[0005]

Therefore, when the (light emission amount) power is changed, the system controller (for example, disclosed in Japanese Patent Application No. 62-59068) also stores the above characteristics of the head. Alternatively, it is necessary to adopt a means such as providing an adjusting means in the LD drive circuit so as to absorb variations in the head, and it is necessary to rewrite the storage data of the controller or readjust the drive circuit every time the head is replaced. In effect, head compatibility is lost.

The present invention has been made in view of the above points, and has as its object to provide an optical recording / reproducing apparatus which can easily emit light with a desired emission power even when an optical head is replaced. I do.

[0007]

According to the present invention, information such as a drive current for enabling light emission at two different light emission amounts is recorded in storage means provided integrally with the optical head. The data can be driven at a desired light emission amount by interpolation or extrapolation based on the data.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIGS. 1 to 4 relate to one embodiment of the present invention.
2 shows the overall configuration of an optical recording / reproducing apparatus according to one embodiment, FIG. 2 shows the configuration of an optical drive system and an optical head, and FIG. 3 shows a case in which light is emitted at a desired light emission amount using information stored in storage means. FIG. 4 shows the contents of processing when recording data.

As shown in FIG. 1, in an optical recording / reproducing apparatus 1 according to one embodiment, an optical head 4 is provided so as to face an optical disk 3 as an optical recording medium which is driven to rotate by a spindle motor 2. ing. The optical head 4 includes an optical head main body 4a having a light source and an optical system having a function of condensing and irradiating a light beam emitted by the light source onto the optical disc 3. The optical head 4 is integrated with the optical head main body 4a to form a PROM as a storage means.
4b is provided. In this embodiment, the PROM 4b is a recording addition voltage D / A with two different light emission amounts (described later).
Is stored.

The system control system 5 controls the entire apparatus 1, records and modulates read data, reads data recorded in the PROM 4b on the optical head 4, and calculates and changes the recording power. This system control system 5
A control signal for recording and reading, modulation data,
LD7 that outputs data of recording addition voltage and forms a light source
By controlling the current flowing (see FIG. 2), a low-power beam for reading and a high-power modulated beam for recording are generated.

The optical head 4 contains a photodetector (not shown) for receiving the reflected light from the optical disk 3. The output of the photodetector is supplied to a track error signal and a focus error signal via a reading system 8. , A recording information reproduction signal is generated and output to the system control system 5. These error signals are output to the head servo system 9 via the system control system 5. The head servo system 9 uses the error signal to control a (lens) actuator (not shown) provided on the optical head 4 so that a light beam spot irradiated on the optical disk 3 correctly traces a recording track.

FIG. 2 shows a main part of the light source driving system 6 and the optical head 4. The back light of the LD 7 is received by, for example, a PIN diode 11 sealed integrally with the LD 7, and outputs a signal corresponding to the light emission amount of the LD 7 to the read power supply circuit 12. In response to the signal output from the PIN diode 11, in the read mode (reproduction mode), the read power supply circuit 12 compares the internal reference level with the detected signal level, and sets the resistance R, the adder 13, A drive signal is output to the V / I converter 15 via the buffer 14, and the V / I converter 15 converts the drive signal into a current to drive the LD 7. By this loop, the APC is performed so that the light emission amount of the LD 7 becomes constant in the reproduction mode.
Operate. In the case of the reproduction mode, the switch 16 connected to the adder 13 via the resistor R is kept OFF. A recording / reading control signal W / R is input from the system control system 5 to the read power supply circuit 12, and when the recording control signal is input, the APC operation is stopped. 13 is output.

The system control system 5 outputs a D / A value for determining an additional voltage for recording light emission to a write power supply circuit 18 via a D / A converter 17. This D / A value is
The system control system 5 reads the information stored in the PROM 4b,
It is determined by calculating the D / A value corresponding to the recording light emission amount by calculation. This D / A value is the D / A converter 17
, The D / A value is converted into an analog amount and output to the write power supply circuit 18. Then, the write power supply circuit 18 converts the analog amount into an addition voltage, outputs the analog amount to the adder 13 via the switch 16 and the resistor R, and adds it to the read level voltage output from the read power supply circuit 12.

In the write mode, the switch 1
6 is turned on / off by the modulation signal MS. When the switch 16 is turned on, the write power supply circuit 18 is turned on.
Is added to the read output signal of the read power supply circuit 12 by the adder 13 and the V / I converter 15
After that, the LD 7 is driven (emits light). In one embodiment, for example, as shown in FIG. 3, the PROM 4b has a value (a value given to the D / A converter 17, hereinafter referred to as D / A converter 17) that determines a drive current for two light emission amounts (for example, 10 mW and 18 mW). A value). FIG. 3 shows that a certain optical head has 40H and 60H (H represents a hexadecimal value). The operation of the embodiment thus configured will be described below.

A) Change of storage power: The system control system 5 first receives two light emission amounts of 10 mW and 18 from the PROM 4 b.
m / W) to the D / A converter 17
Read the value. In this case, as shown in FIG. 3, the D / A values are 40H and 60H. On the other hand, a desired light emission power P is given from outside through, for example, a keyboard or the like (in FIG. 3, the light emission power is, for example, 16 mW or 19 mW
Is given).

The system control system 5 has a relational expression: DA = (60H−40H) / (18−10) × (P−10) + 40H (where DA is the D / A value, and P is the desired emission power) Is the unit of mW.), The D / A value is obtained. For example, when P is 16 mW, 58H is obtained, and this value 58H is set in the D / A converter 17.

Even when the desired light emission amount is, for example, 18 mW or more or 10 mW or less, the D / A value can be obtained by extrapolating a straight line. (For example, P = 19
It can be seen from FIG. 3 that in the case of mW, 64H is obtained as a D / A value by extrapolation. As described above, D at a predetermined light emission amount (here, 18 mW and 10 mW) for each optical head.
By recording the / A value, a drive current value for an arbitrary light emission amount can be easily obtained by substituting a new D / A value into the above relational expression even when the optical head is replaced.

B) Data recording: The system control system 5 first digitally modulates data to be recorded, converts the data into bit serial data, and outputs the data to the light source driving system 6 together with a control signal for instructing recording. The light source driving system 6 stops the APC operation while the recording control signal instructs the recording, and through the switch 16 to the read voltage output from the read power supply 12 through the switch 16, the recording addition specified by the above method. The voltage is added by the adder 13, and the LD 7 is driven via the V / I converter 15. In this case, the switch 16 is controlled by the modulation signal MS. In this manner, the light beam of the LD 7 is modulated, and the head servo system 9 controls so that the light beam follows a desired track during this time, so that writing is performed.

FIG. 4 shows a flow of the data recording operation. At step S1, stored information is read from PROM 4b, and then at step S2, D / A
An operation for calculating the value is performed. D obtained by this calculation
After the / A value is set (step S3), the write operation shown in step S4 is performed.

C) Reading of data: The system control system 5 informs the light source drive system 6 that reading is to be performed by a control signal. The light source drive system 6 emits light for reading, and the head servo system 9 controls the beam to follow a desired track. As a result, a read signal is output from the optical head 4. The read system 8 converts the read signal into a digital signal and outputs the digital signal to the system control system 5. The data is demodulated here and reading is completed.

In the above-described embodiment, after the D / A value is determined, the level of the read voltage output from the read power supply circuit is subtracted (converted to a value corresponding to the D / A value). By outputting the light, it is possible to emit light with a desired light emission amount with high accuracy. Also, L of the optical head body 4a
When a temperature sensor is mounted integrally with the D7 or the PROM 4b and the D / A value is determined, the D / A
The A value may be determined. In this case, LD
7 may be stored in the PROM 4b, and the D / A value under that temperature condition can be determined based on this information.

The present invention is not limited to this embodiment, and can be applied not only to a semiconductor laser but also to a gas laser and an LED as a light source element. PROM, EPROM, EEPROM is used to store information on drive current and light emission value.
Modifications such as M and DIP switches are possible. When the current-luminous characteristics of the light source are not linear, for example, one D /
The coefficient of a relational expression for obtaining an A value and another D / A value, the coefficient of a relational expression for obtaining at least two other D / A values, or the D / A values of a plurality of light emission values are stored. Then, it is possible to easily cope with a deformation such as partial linear approximation.

[0023]

As described above, by storing information on the drive current recorded in each optical head,
Since the drive current at the desired power can be calculated, the power can be easily changed to the desired power even if the optical head changes.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical recording / reproducing apparatus according to one embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a main part of an optical drive system and an optical head.

FIG. 3 is an explanatory diagram for obtaining a value corresponding to a drive current for causing light emission at a desired light emission amount from information stored in a storage unit.

FIG. 4 is a flowchart showing processing contents at the time of data recording.

FIG. 5 is an explanatory diagram showing that a light emission amount with respect to a drive current differs for each optical head in a conventional example.

[Explanation of symbols]

 1 Optical recording / reproducing device 3 Optical disk 4 Optical head 4a Optical head body 4b PROM 5 System control system 6 Light source driving system 7 LD (laser Diode) 8 Reading system 9 Head servo system 12 Read power circuit 13 Adder 15 V / I converter 16 Switch 17 D / A converter 18 Write power circuit

Claims (1)

(57) [Claims] 1. An optical recording / reproducing apparatus for optically recording and / or reproducing data, comprising: an optical head integrated with an optical head; A ROM for storing a drive current value corresponding to the amount and a coefficient value representing a relationship between the drive current corresponding to the light emission amount, a means for externally providing a desired light emission amount, Calculating means for calculating a coefficient value corresponding to the desired light emission amount, and calculating a drive current value corresponding to the desired light emission amount based on the calculated coefficient value. apparatus.