JPH05159341A - Optical pickup device - Google Patents

Abstract

PURPOSE:To control the level of a laser beam at a suitable value without being affected by the dirt of an optical plane by providing a detector to detect the output level of a semiconductor laser element at a mobile optical system. CONSTITUTION:When the surfaces of cover glass 5, 7 provided in enclosures 4, 6 are made dirty and the permeability is lowered since dust entering an optical disk driving device is stuck, the light level of light flux made incident to the mobile optical system is lowered. In this case, since the level of a photodetecting signal Pm outputted from a monitor element 15 is lowered as well, a semiconductor laser drive control part 30 controls the level of the driving signal of a semiconductor laser element 1 so that the strength of laser beams converged onto an optical disk 10 can be at a rated value. Thus, the recording operation and reproducing operation of data to the optical disk 10 are executed in a normal state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed optical system provided with at least a semiconductor laser element serving as a light source and a detection optical system, and at least an optical axis of the objective lens and the fixed optical system to coincide with an optical axis of the objective lens. The present invention relates to an optical pickup device provided with a separation optical system divided into moving optical systems provided with a deflection prism.

[0002]

2. Description of the Related Art In an apparatus using an optical recording medium as a recording medium such as an optical disk device, data is recorded / recorded on the recording medium.
An optical pickup device for reproducing / erasing is provided. The optical pickup device is provided with a moving mechanism for moving in the radial direction of the optical disc, and it is necessary to move the optical pickup device at high speed in order to shorten the time required for data access of the optical disc device.

Therefore, conventionally, a moving optical system provided with an objective lens and a deflection prism for aligning the optical axis of the laser beam with the optical axis of the objective lens, a semiconductor laser element as a light source, and various signals. An optical pickup device of a separation optical system, which is divided into a fixed optical system provided with a detection optical system for forming the optical disk, is in practical use.

FIG. 5 shows a main part of a conventional example of an optical pickup device having a separation optical system.

In FIG. 1, the light output from the semiconductor laser device 1 is converted into parallel light by the coupling lens 2 and then the light beam is split by the beam splitter 3. The light beam transmitted through the beam splitter 3 is , A cover glass 5 provided in a housing 4 of a fixed optical system, a cover glass 7 provided in a housing 6 of a moving optical system, a reflection by a deflection prism 8 and a deflection by an objective lens 9, Focused on 10.

The reflected light from the optical disk 10 passes through the objective lens 9 and is converted into substantially parallel light, reflected by the deflecting prism 8, transmitted through the cover glass 7, and covered by the cover glass 5.
And is incident on the beam splitter 3. And
This reflected light is split by the beam splitter 3, and the light flux reflected by the beam splitter 3 is a reproduction signal,
It is guided to a detection optical system (not shown) for forming a focusing error signal and a tracking error signal.

On the other hand, of the parallel light that has passed through the coupling lens 2, the light beam reflected by the beam splitter 3 is incident on a monitor light receiving element 11 for detecting the output level of the semiconductor laser element 1. Also, the seek mechanism 1
2 is for moving the housing 6 in the radial direction of the optical disk 10.

The output level of the semiconductor laser device 1 is controlled to a predetermined value based on the light receiving signal of the monitor light receiving device 11.

[0009]

However, such a conventional device has the following disadvantages.

That is, if such an optical pickup device is used for a long period of time, dust that slightly penetrates into the magneto-optical disk drive device adheres to the cover glasses 5 and 7, and the cover glasses 5 and 7 are exposed. The surface is dirty,
Since the transmittance is deteriorated, the level of the laser beam actually focused on the surface of the magneto-optical disk 10 is lowered as compared with the level in the initial state.

On the other hand, the monitor light receiving element 11 includes the housing 4
Since it is provided inside, the output level of the semiconductor laser device 1 is controlled in the same manner as in the initial state without being affected by dirt on the optical surface due to dust.

As a result, when it is used for a long period of time, the level of the laser beam focused on the optical disk 10 is lowered, which causes a problem that data recording / reproducing / erasing operations cannot be normally performed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical pickup device capable of controlling the level of a laser beam to an appropriate value without being affected by dirt on an optical surface. There is.

[0014]

According to the present invention, a fixed optical system provided with at least a semiconductor laser element serving as a light source and a detection optical system, and at least an objective lens and an optical axis of the fixed optical system are set to an optical axis of the objective lens. An optical pickup device having a splitting optical system divided into a moving optical system provided with a deflecting prism for matching, in which a detecting element for detecting the output level of the semiconductor laser element is provided in the moving optical system. Is. Further, the detection element is a light receiving element that receives a light beam that has not been reflected by the deflection prism.

Further, a fixed optical system provided with at least a semiconductor laser element serving as a light source and a detection optical system, and at least an objective lens and a deflection prism for aligning the optical axes of the fixed optical system with the optical axis of the objective lens are provided. In the optical pickup device provided with the splitting optical system divided into the moving optical system, a beam splitting means which is provided in the fixed optical system and splits a part of the light flux of the semiconductor laser element to output to the moving optical system. And a light receiving element provided in the moving optical system for receiving the light beam separated by the light beam separating means, and a control means for determining the output level of the semiconductor laser element based on a light receiving signal of the light receiving element. Is. The light receiving element is provided outside or inside the housing of the moving optical system.

[0016]

Therefore, since the detection element is affected by the dirt on the optical surface, the detection value of the detection element corresponds to the actual value of the intensity of the laser beam focused on the recording medium. As a result, the laser beam intensity can be controlled more appropriately.

[0017]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an optical pickup device according to an embodiment of the present invention. In addition, in FIG.
The same parts and corresponding parts are designated by the same reference numerals.

In the figure, the light beam incident on the moving optical system from the fixed optical system is reflected by the deflection prism 8 at its central portion and guided toward the objective lens 9, and the peripheral portion of the light beam is deflected by the deflection prism. The light is incident on the monitor light receiving element 15 which is arranged behind the deflecting prism 8 and whose light receiving surface is set wider than the side surface of the deflecting prism 8.

The cross section of the parallel light beam formed by the coupling lens 2 is arranged so that a part of the light beam output from the fixed optical system can be incident on the monitor light receiving element 15 arranged behind the deflecting prism 8. , Wider than the reflecting surface of the deflecting prism 8.

FIG. 2 shows an example of a control system of the optical pickup device shown in FIG.

In the figure, the detection optical system 2 of the fixed optical system is shown.
The light reception signal PS output from the detection light receiving element (not shown) provided in 0 is input to the signal detection unit 21, and the signal detection unit 21 causes the tracking error signal ET, the focusing error signal EF, and the reproduction. The signal RF is formed, the tracking error signal ET is applied to the tracking servo control unit 22, and the focusing error signal EF is generated.
Is applied to the focusing servo control section 23, and the reproduction signal RF is applied to the signal reproduction section 24.

The tracking servo control section 22 forms a tracking control signal ST for changing the tracking error to 0 based on the input tracking error signal ET. The tracking control signal ST is the tracking actuator drive section 25. Has been added to.

Tracking actuator drive unit 25
On the basis of the input tracking control signal ST, supplies a drive current to a tracking actuator for moving the objective lens 9 in the tracking direction in the objective lens moving mechanism attached to the objective lens 9.

The focusing servo control unit 23 changes the focusing error to 0 based on the input focusing error signal ET.
The focusing control signal SF, which forms F, is applied to the focusing actuator drive unit 26.

Focusing actuator drive unit 26
Is to supply a drive current to a focusing actuator that moves the objective lens 9 in the front-back direction of the optical axis in the objective lens moving mechanism based on the input focusing control signal SF.

The signal reproducing unit 24 receives the input reproduction signal RF.
The reproduction data RD recorded on the optical disc 10 is formed on the basis of
Each is added to the decoder 27.

The decoder 27 uses the error correction code added to the input reproduction data RD to reproduce the reproduction data RD.
Is detected and corrected, and its output data is added to the control unit 28 as reproduction data RDa.

The encoder 29 adds a predetermined error correction code to the recording data WD output from the controller 28, and the output data is added to the semiconductor laser drive controller 30 as a recording signal WDa. ing.

The light receiving signal Pm output from the monitor light receiving element 15 is applied to the semiconductor laser drive controller 30. When the reproduction mode is set by the control unit 28, the semiconductor laser drive control unit 30 drives the semiconductor laser element 21 to be turned on and also receives the light receiving signal Pm at that time.
The drive signal level of the semiconductor laser device 1 is controlled so that the level of 1 becomes a predetermined value during reproduction. In addition, the control unit 28
When the recording mode is set further, the encoder 29
The semiconductor laser 1 is driven to light based on the recording signal WDa added from the above, and the level of the drive signal is controlled so that the level of the light receiving signal Pm at that time becomes a predetermined value at the time of recording.

The position detector 31 detects the position of the housing 6 moved by the seek mechanism 12, and the detection signal thereof is applied to the seek motor controller 32 as a position detection signal SP.

The seek motor control section 32 drives the seek motor 32, which is the drive source of the seek mechanism 12, so that the value of the position detection signal SP becomes a value corresponding to the target position instructed by the control section 28. It is a thing.

The speed detector 33 detects the rotation speed of the spindle motor 34 for rotationally driving the optical disk 10. The detection signal is applied to the spindle motor controller 35 as a speed detection signal SV. ..

The spindle motor control section 35 drives the spindle motor 34 so that the value of the speed detection signal SV becomes a value corresponding to the target speed instructed by the control section 28.

Further, the host interface circuit 36 is
This is for exchanging various data with a host device that uses this optical disk drive device as an external storage device.

With the above configuration, when the optical disk 10 is mounted on the optical disk drive, the spindle motor control section 3
5, the spindle motor 24 is rotated at a predetermined rotation speed, and the data recording / reproducing operation on the optical disc 10 by the optical pickup device becomes possible.

Then, the control unit 28 operates the semiconductor laser drive control unit 30 in the reproduction mode with the housing 6 moved to the predetermined initial position by the seek mechanism 12, and the reflected light from the recording surface of the optical disk 10 is generated. Obtained, control unit 28
Starts the operation of the focusing servo control unit 23. Thereby, the focusing servo control operation is performed by the focusing servo control unit 23, and the focus position of the objective lens 9 is controlled so as to coincide with the recording surface of the optical disc 4.

When the control of the focusing servo control section 23 is locked, the control section 28 starts the operation of the tracking servo control section 22. As a result, the tracking servo control operation by the tracking servo control section 22 is performed. , The laser beam follows the recording track.

When the control of the tracking servo control unit 22 is in the locked state, an appropriate reproduction signal RF is input to the signal reproduction unit 24, so that the control unit 28 causes the signal reproduction unit 2 to operate.
The operation of 4 is started. As a result, the reproduction data RD is output from the signal reproduction unit 24 to the decoder 27, which causes the reproduction data RDa to be transmitted to the control unit 28.
Added by. Here, when there is a request from the host device, the control unit 28 outputs the reproduction data RDa to the host device via the host interface circuit 36.

When recording data, the control unit 28
The recording data WD input via the host interface circuit 36 is output to the encoder 29 with the semiconductor laser drive controller 30 set to the recording mode.

As a result, the recording signal W is output from the encoder 29.
Da is added to the semiconductor laser drive control unit 30, whereby the semiconductor laser drive control unit 30 causes the recording signal WDa.
The semiconductor laser element 1 is driven to light based on the above, and the level of the drive signal is controlled so that the level of the light receiving signal Pm becomes a predetermined value during recording.

In this way, the data recording / reproducing operation for the optical disc 10 is performed.

Here, when dust that has entered the optical disk drive device adheres and the surfaces of the cover glasses 5 and 7 provided on the housings 4 and 6 are dirty and the transmittance decreases, the moving optical system is used. The light level of the light beam incident on the system is reduced.

As a result, the intensity of the laser beam focused on the optical disk 10 from the objective lens 9 decreases. At the same time, the light level of the light beam incident on the monitor light receiving element 15 also decreases, so that the level of the light reception signal Pm output from the monitor light receiving element 15 also decreases.

On the other hand, the semiconductor laser drive controller 30 controls the drive signal of the semiconductor laser element 1 so that the level of the light receiving signal Pm becomes a predetermined value.

Therefore, as described above, when the light level of the light beam incident on the moving optical system is lowered and the intensity of the laser beam focused on the optical disk 10 is lowered, the output from the monitor light receiving element 15 is outputted. Since the level of the received light receiving signal Pm is also lowered, the semiconductor laser drive controller 3
0 controls the level of the drive signal of the semiconductor laser element 1 so that the intensity of the laser beam focused on the optical disc 10 becomes a specified value, and as a result, the data recording and reproducing operations on the optical disc 10 are in a normal state. Done in.

In this way, in this embodiment, data can be recorded / reproduced on / from the optical disk 10 without being affected by the dirt on the optical surface of the optical system, and the reliability of the data recording of the optical disk drive device. Can be improved.

FIG. 3 shows an optical pickup device according to another embodiment of the present invention. In the figure, the same parts as those in FIG. 1 and corresponding parts are designated by the same reference numerals.

In the figure, of the parallel light flux formed by the coupling lens 2, the polarization beam splitter 3
The light beam reflected by is guided by the deflecting prism 16 in a direction parallel to the light beam passing through the polarization beam splitter 3, and this light beam is transmitted through the upper portion of the cover glass 5a,
The monitor light receiving element 15 provided inside the housing 6 through the upper portion of the cover glass 7a of the housing 6 of the moving optical system.
Is incident on.

The cover glasses 5a and 7a are respectively extended upward so that the light flux incident on the monitor light receiving element 15 can pass therethrough.

In this way, in this embodiment, the light flux incident on the monitor light receiving element 15 is transmitted through the cover glasses 5a and 7a in the same manner as the light flux incident on the objective lens 9, so that the above-described embodiment is performed. Similarly to the example, since the light receiving signal Pm output from the monitor light receiving element 15 reflects the influence of dirt on the optical surface, the data recording / reproducing operation on the optical disc 10 can be normally performed.

FIG. 4 shows an optical pickup device according to still another embodiment of the present invention. In the figure, the same parts as those in FIGS. 1 and 3 and corresponding parts are designated by the same reference numerals.

In the figure, of the parallel light flux formed by the coupling lens 2, the polarization beam splitter 3
The light beam reflected by is guided by the deflecting prism 16 in a direction parallel to the light beam passing through the polarization beam splitter 3, and this light beam is transmitted through the upper portion of the cover glass 5a,
The light is incident on the monitor light receiving element 15 provided on the cover glass 7 on the outer surface of the housing 6 of the moving optical system.

Here, since the monitor light receiving element 15 is provided outside the housing 6, dust that has entered the optical disk drive device adheres to the light receiving surface thereof, and its optical surface is the same as the cover glass 7. Get dirty.

In this way, in the present embodiment, the light beam incident on the monitor light receiving element 15 is affected by the dirt on the optical surface in the same manner as the light beam incident on the objective lens 9, so that the above-described embodiment is performed. Similar to the example, the data recording / reproducing operation on the optical disc 10 can be normally performed.

Although the present invention is applied to the optical pickup device for recording / reproducing data on / from the optical disk in the above-mentioned embodiments, the present invention is similarly applied to other optical pickup devices. can do.

[0057]

As described above, according to the present invention,
Since the detection element is affected by dirt on the optical surface, the detection value of the detection element corresponds to the actual value of the intensity of the laser beam focused on the recording medium,
As a result, the effect that the laser beam intensity can be controlled more appropriately is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an optical pickup device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a control system applied to the optical pickup device of FIG.

FIG. 3 is a schematic configuration diagram showing an optical pickup device according to another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing an optical pickup device according to still another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a conventional example of an optical pickup device of a separation optical system.

[Explanation of symbols]

 4,6 Housing 5,5a, 7,7a Cover glass 15 Monitor light receiving element 30 Semiconductor laser drive controller

Claims (5)

[Claims] 1. A fixed optical system provided with at least a semiconductor laser element serving as a light source and a detection optical system, and at least an objective lens and a deflection prism for aligning the optical axis of the fixed optical system with the optical axis of the objective lens. An optical pickup device including a separation optical system divided into the moving optical system, wherein a detecting element for detecting an output level of the semiconductor laser element is provided in the moving optical system. 2. The optical pickup device according to claim 1, wherein the detection element is a light receiving element that receives a light beam that has not been reflected by the deflection prism. 3. A fixed optical system provided with at least a semiconductor laser element serving as a light source and a detection optical system, and a deflection prism for aligning at least an optical axis of the objective lens and the fixed optical system with an optical axis of the objective lens. In the optical pickup device provided with the splitting optical system divided into the moving optical system, a beam splitting means which is provided in the fixed optical system and splits a part of the light flux of the semiconductor laser element to output to the moving optical system. And a light receiving element which is provided in the moving optical system and receives the light beam separated by the light beam separating means,
An optical pickup device comprising control means for determining an output level of the semiconductor laser element based on a light receiving signal of the light receiving element. 4. The optical pickup device according to claim 3, wherein the light receiving element is provided outside a housing of the moving optical system. 5. The optical pickup device according to claim 3, wherein the light receiving element is provided inside a housing of the moving optical system.