JPS63298826A - Optical pickup device - Google Patents

Abstract

PURPOSE:To attain each of replacement of various kinds of optical pickup devices depending on the preference of user by adjusting in advance to variance in the servo performance of an optical pickup to output a prescribed output signal. CONSTITUTION:A focus error signal from a photoelectric converter is inputted to a servo control circuit 14, adjusted and converted into a prescribed focus servo signal, an objective lens 16 provided to an optical pickup is driven toward the focus direction to correct the focus deviation. Moreover, a track error electric signal from the photoelectric converter is inputted to a servo control circuit 14, where the signal is adjusted and converted into a prescribed track servo signal, the objective lens 16 of the optical pickup 12 is driven toward the track direction to correct the track deviation. Thus, even when a general user replaces the optical pickup device 2, the variance in the servo performance is adjusted in advance minutely. Thus, the compatibility to the optical information reader such as a Compact disk player is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical pickup device, and particularly to an optical pickup device that is compatible with an optical information reader such as a compact disc player.

[Prior Art] In recent years, digital information recording systems that can store extremely large amounts of information at high density and with good stability have been developed, including compact disc players, laser disc players, optical disc file devices, and magneto-optical files. It is used as equipment in various fields.

In such optical information recording systems, optical pickup devices have extremely important significance in order to read signals from optical information recording media such as compact discs.
This optical pickup device irradiates a signal recording surface of an optical information recording medium with a laser beam or the like, and outputs a predetermined information reading signal based on the reflected light from the recording surface.

For example, when incorporating an optical pickup device into a compact disc player, a width of 0.1μ on the compact disc,
Correctly trace a signal group with a length of 0.9 to 3.3μ,
In order to read signals accurately, it is necessary to constantly control the focus of the reading light on the optical disk of the optical pickup device, which makes adjusting the servo circuit troublesome and requires fine adjustment using various adjustment circuits. There is a need to do.

However, conventional optical pickup devices consist of a signal reading device itself consisting of a complex optical system, or a very basic configuration with an attached laser diode output power control circuit, and the performance of the optical pickup device is limited to a certain extent. It was something I couldn't do.

Therefore, it is difficult to adjust the servo circuit when incorporating the optical pickup device into a compact disc player, etc.
Fine adjustments had to be made using various adjustment circuits, which required a great deal of labor during assembly.

[Problems to be Solved by the Invention] Conventional Problems As mentioned above, conventional optical pickup devices require extremely complicated operations even when installed, and replacement work is difficult during installation. Ta. That is, it is extremely difficult for general users to easily replace the pickup cartridge as a signal detector and create sounds according to each user's preference, as in an analog record player.

However, due to the diversification and individualization of users' tastes in recent years, there is a strong demand for an optical pickup device that can easily replace the optical pickup device that is the entrance for audio signals. It has become extremely important for the user to be able to easily replace the disc player in order to increase the widespread use of compact disc players and the like.

OBJECT OF THE INVENTION The present invention was made to solve the above problems, and an object of the present invention is to provide a pickup device that is compatible with optical information readers such as compact disc players.

[Means and operations for solving the problems] In order to achieve the above object, the present invention provides an objective lens for projecting focused light onto a signal surface of an optical information recording medium, and an objective lens for projecting focused light onto a signal surface of an optical information recording medium. an optical pickup having an optical/electrical converter that receives reflected light and outputs a corresponding electrical signal; and an optical pickup that includes an optical/electrical converter that receives reflected light and outputs a corresponding electrical signal; a focus servo adjustment conversion circuit that adjusts and converts a focus error electric signal into a predetermined focus servo signal and outputs the same; and the optical/electrical converter that corresponds to a track deviation from one signal track on the signal surface of the optical information recording medium. The present invention is characterized by comprising a track servo adjustment conversion circuit that adjusts and converts a track error electrical signal from the servo into a predetermined track servo signal and outputs the signal.

With the present invention configured as described above, the focus error electrical signal from the optical/electrical converter is input to the focus servo conversion circuit and adjusted and converted into a predetermined focus servo signal. As a result, the objective lens provided in the optical pickup is driven in the focus direction, and the focus shift is corrected. Further, the track error electrical signal from the optical/electrical converter is input to a track servo conversion circuit, and is adjusted and converted into a predetermined track servo signal. As a result, the objective lens of the optical pickup is driven in the track direction, and track deviation is corrected.

As described above, since the focus servo conversion circuit and the track servo conversion circuit adjust and convert the focus error electric signal or track error electric signal, respectively, into a servo signal, even if a general user replaces the optical pickup device, It has the advantage that variations in servo performance are finely adjusted in advance and there is no impact on the information reading function.

[Example] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a functional block diagram of a compact disc player (hereinafter referred to as "rCD player") equipped with an optical pickup device according to an embodiment of the present invention.

The CD player applied to this embodiment includes an optical pickup device (2), a disk motor (4) that rotationally drives an optical disk (3), and a system control circuit that controls the CD player according to various operations by the user. (5). The information detected by the optical pickup device (2) is input to the gain adjustment circuit (6) as an HF signal with a predetermined voltage value, and after being adjusted to a constant voltage signal,
The signal is input to a signal processing circuit (7). Here, the signal processing circuit (7) includes a D/A conversion circuit (8) and an amplifier circuit (9).
The audio signal is output via R.

The signal processing circuit (7) also serves as a disk motor servo circuit, and controls the rotation of the disk motor (4) via the disk motor drive circuit (10).

Note that the system control circuit (5) causes the optical pickup device (2) to emit a constant laser power via the laser drive circuit (11).

The optical pickup device (2) includes an optical pickup (
12), a preamplifier circuit (13), a servo control circuit (14), and an actuator drive circuit (1
5). The optical pickup (12) has an objective lens (
16) and a focus actuator (F-ACT) that finely adjusts the relative position of the objective lens and the optical disk (3).
) (17) and tracking actuator (T・AC
T) (1g), a photodetector (19) that receives reflected light from the optical disk (3) and outputs an electric signal according to the signal on the optical disk (3), and the laser drive circuit (11).
It is composed of an ALPC section (an output power control section including a laser diode) (20) which emits a laser beam based on a command and electromagnetically controls the output power.

Further, the preamplifier circuit (13) amplifies and converts the electric signal from the photodetector (19), and generates an H-F signal S1, which is an electric signal corresponding to the information on the optical disk (3), and an electric signal corresponding to the defocus. It outputs an F·E signal S2 which is , and a T-E signal S3 which is an electric signal corresponding to the deviation from the signal sequence. The H-F signal S1 is input to the gain adjustment circuit (6), the F-E signal S2 is input to the E-F balance circuit (21), and the T-E signal S3 is input to the T-E balance circuit (21). 22) respectively.

The E-F balance circuit (21) receives the F-E signal S2 and moves the objective lens (16) from the focused position to the optical disc (3).
) is outputted to the FE signal processing circuit (23), which corrects the difference in the balance of the output level of the signal corresponding to the focus shift when approaching and moving away from the object.

The F-E signal processing circuit (23) includes a focus servo offset (FSO) adjustment circuit (24) that adjusts the neutral point of the E-F signal to match the maximum point of the H-F signal S1, and a gain light a focus servo gain (FSG) adjustment circuit (25) that adjusts the point, low frequency gain, high frequency gain, phase compensation, etc. to predetermined values;
-Convert and output the E signal S2 to a constant FE control signal.

On the other hand, the T-E balance circuit (22) receives the T-E signal S3 and outputs a signal corresponding to the deviation of the optical disk (3) from the center of the track row to the inner and outer peripheries, for example, balances output levels such as DC levels. The signal corrected for the difference in T-E
Output to the signal processing circuit (26).

The T-E signal processing circuit (26) performs a track servo offset (
TSO) adjustment circuit (27), and a track servo gain (TSG) adjustment circuit (28) that adjusts the gain light spot, low-frequency gain, high-frequency gain, phase compensation, etc. to predetermined values.
), and exchanges and outputs the TE signal S3 as a constant TE control signal.

The outputs of the F-E signal processing circuit (23) and the T-E signal processing circuit (26) are output from the servo control circuit (
14) and the servo control circuit (14)
is the focus servo (FS) signal S4 from each control signal.
and a track servo (TS) signal S5 to the actuator drive circuit (15).

The optical pickup device according to this embodiment is roughly constructed as described above, and its operation will be explained next.

First, under the control of the system control circuit (5) based on the user's operation, power is supplied to the ALPC unit (20) via the laser drive circuit (11), and the laser beam is directed from the objective lens (16) to the optical disc (3). The direction is emitted. Then, the photodetector (19) outputs a predetermined electrical signal to the preamplifier circuit (13) based on the reflected light from the optical disk (3).

The preamplifier circuit (13) outputs the F-E signal S2,
The control signal that has undergone predetermined conversion processing is manually input to the servo control circuit (14), which drives the focus actuator (17) via the actuator drive circuit (15) to focus on the signal plane of the optical disc (3). will be held.

In response to this focusing signal, the disk motor (4) is driven and the optical disk (3) rotates.

Then, the tracking actuator (18) is driven, and focusing is performed correctly at the position of a predetermined signal controlled by the preamplifier circuit (13), servo control circuit (14), etc. As described above, the signal from the optical disc (3) is processed and the audio signal R is output.

Here, even when the user obtains the optical pickup device (2) of his choice and assembles it into this compact disc player, if he is using an optical pickup device that has a servo circuit that has already been adjusted to a predetermined level, the connection Since the signal lines and feeder lines that are connected can be at a predetermined voltage level, delicate adjustments are not necessary. It goes without saying that not only electrical adjustments but also mechanical adjustments are made.

Note that the optical pickup device according to the present invention is not limited to the above-described embodiments, and it is sufficient to adjust the performance variations of the optical pickup in advance so that it can be controlled, for example, at a predetermined voltage level, and the gain adjustment circuit ( 6) may be used as an optical pickup device.

Further, the optical disc device is not limited to a compact disc player, but can also be applied to devices using optical/electrical signal conversion such as a laser disc breaker, an optical disc file device, and a magneto-optical file.

Further, the present invention has the advantage that the user can easily replace the optical pickup device if it is damaged.

[Effects of the Invention] As explained above, according to the optical pickup device according to the present invention, variations in the servo performance of the optical pickup are adjusted in advance and a constant output signal is output.
This has the effect that various optical pickup devices can be easily replaced according to the user's preference.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of an optical pickup device according to an embodiment of the present invention adapted to a compact disc player. In the figure, (2) is an optical pickup device, (3) is an optical disk, (12) is an optical pickup, (13) is a preamplifier circuit, (14) is a servo control circuit, and (1) is a preamplifier circuit.
6) is an objective lens.

Claims (1)

[Claims] an optical pickup having an objective lens that projects focused light onto a signal surface of an optical information recording medium and an optical/electrical converter that receives reflected light from the signal surface of the optical information recording medium and outputs a corresponding electrical signal; a focus servo adjustment conversion circuit that adjusts and converts a focus error electrical signal from the optical/electrical converter corresponding to a focal shift of at least a signal on a signal surface of the optical information recording medium into a predetermined focus servo signal, and outputs the same; a track servo adjustment conversion circuit that adjusts and converts a track error electrical signal from the optical/electrical converter corresponding to a track deviation from one signal track on the signal surface of the optical information recording medium into a predetermined track servo signal and outputs the same; An optical pickup device comprising: