JP2003346376A - Optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely control the output of a semiconductor laser chip by efficiently using the light outputted by the laser chip. <P>SOLUTION: The optical pickup device 20 includes a light source 21, a photosensor 22, a light condenser 23, and a control 24. On the photosensor 22, the light condenser 23 condenses the light outputted by the light source 21 but not used for recording or reproduction. Since the photosensor 22 can receive both the light directly outputted by the light source 21 but not used for information recording or reproduction and the light condensed by the condenser 23, the amount of the light is increased to control the output light, and the control precision can be improved. Further, the efficiency can be improved for the light by using the light outputted by the light source 21 but not used for information recording or reproduction for the purpose of controlling the light amount without reducing the amount of the unused light. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device for recording or reproducing information on an optical recording medium.

[0002]

2. Description of the Related Art A semiconductor laser device, which is one type of light source provided in an optical pickup device, outputs a laser beam, and the laser beam is used for recording or reproducing information on an optical recording medium. Since the output of a semiconductor laser chip that emits light provided in a semiconductor laser device fluctuates due to changes in the ambient temperature used and aging, automatic output control (Au
The drive current of the semiconductor laser chip is controlled by a tomatic power control (APC) circuit, and the output is kept constant. As a system for keeping the output of the semiconductor laser chip constant by the APC circuit, a rear monitor system and a front monitor system are known.

[0003] The rear monitor system is a system in which light emitted in a direction opposite to the direction of light emitted from a semiconductor laser chip toward an optical recording medium (hereinafter referred to as a rear direction) is used for output control. The light emitted in the rear direction is received on output control light detecting means provided in the semiconductor laser device, and responds to a detection output from the output control light detecting means,
The PC circuit supplies a signal for controlling the drive current of the semiconductor laser chip to the semiconductor laser device, and controls the output so as to be constant.

However, the amount of light emitted in the rear direction is smaller than the amount of light emitted in the direction of the optical recording medium (hereinafter referred to as the front direction) for recording or reproducing information on or from the optical recording medium. Since it is small, it is not enough to control the output of the semiconductor laser chip.

For this reason, a front monitor system utilizing light emitted in the front direction is widely used. FIG. 10 is a system diagram showing a simplified configuration of a conventional optical pickup device 1. Light emitted from the semiconductor laser chip 3 provided in the semiconductor laser device 2 is collimated by the collimator lens 4 and enters the beam splitter 5. The beam splitter 5 is, for example, 95% of the incident light.
%, And a reflecting film that reflects 5%
, Most of the light is transmitted in the direction of the optical recording medium 10, and the remaining light is reflected in the direction of the output control light detecting means 7.

The light transmitted through the beam splitter 5 is polarized by the quarter-wave plate 8, bent 90 degrees by the rising mirror 9, guided to the optical recording medium 10, and collected by the objective lens 11. Thus, a light spot having a prescribed size is formed on the information recording surface of the optical recording medium 10, and information is recorded or reproduced. The light reflected by the optical recording medium 10 passes through the objective lens 11, is bent 90 degrees by the rising mirror 9, is polarized by the quarter-wave plate 8, and enters the beam splitter 5. The beam splitter 5 outputs 100% of the reflected light from the optical recording medium 10.
Is reflected in the direction of the light receiving means 12, and the reflected light is condensed by the condensing lens 13 and the cylindrical lens 1
After the astigmatism is given by 4, the light is received on the light receiving means 12 and the information on the optical recording medium is read.

The light reflected by the beam splitter 5 toward the output control light detecting means 7 is condensed by a condenser lens 15 and received on the output control light detecting means 7. In response to the detection output from the output control light detection means 7,
The APC circuit 16 supplies a signal for controlling the drive current of the semiconductor laser chip 3 to the semiconductor laser device 2, and controls the output so as to be kept constant.

[0008]

SUMMARY OF THE INVENTION In order to reduce the load on a semiconductor laser chip and save power, and to provide a high-power semiconductor laser device required for recording information on an optical recording medium. Therefore, it is necessary to efficiently use light emitted from a semiconductor laser chip for output control.

FIG. 11 is a system diagram showing a simplified configuration of another conventional optical pickup device 17. Another conventional optical pickup device 17 is an example of the prior art in which light emitted from a semiconductor laser chip is efficiently used for output control. Since the light emitted from the semiconductor laser chip 3 is diffused light, there is light 18 that diffuses outward without entering the collimator lens 4.
The diffused light 18 is detected by the output control light detecting means 7, and in response to the detected output, the APC circuit 16 supplies a signal for controlling the drive current of the semiconductor laser chip 3 to the semiconductor laser device 2, and the output is kept constant. Dripping.

However, such another conventional optical pickup device 17 has the following problems. The output control light detecting means 7 uses the light emitted from the semiconductor laser chip 3 and diffused outward without entering the collimator lens 4.
Only a small amount of light can be received. Therefore, the amount of light received is too small to accurately control the output of the semiconductor laser chip 3 by the APC circuit 16, and thus the reliability of the output control is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical pickup device which has a high use efficiency of light emitted from a semiconductor laser chip and which can accurately control the output of the semiconductor laser chip.

[0012]

SUMMARY OF THE INVENTION The present invention relates to an optical pickup device for recording or reproducing information on or from an optical recording medium by light, and a light source for emitting light and a light for detecting light emitted from the light source. Detecting means, condensing means for condensing light emitted from the light source and not used for recording or reproduction of information on the light detecting means, and output of light emitted from the light source in response to output from the light detecting means And a control means for controlling the optical pickup.

According to the present invention, a signal based on the amount of light detected by the light detecting means is output, and in response to the output signal, the control means outputs the light emitted from the light source (hereinafter referred to as the light output for convenience). May be abbreviated).
Since the light detection means can receive both light emitted from the light source and directly incident without being used for recording or reproduction of information and light incident and condensed by the light condensing means, the light detection means can be used for light output control. The amount of light that can be used increases, and the accuracy of light output control can be improved.

Further, since light emitted from the light source and not used for recording or reproducing information is used for light output control, utilization of light without decreasing the amount of light emitted from the light source and used for recording or reproducing information is used. Efficiency can be increased.

Further, the present invention is characterized in that the light condensing means is a reflection mirror for reflecting the light emitted from the light source toward the light detecting means.

According to the present invention, the reflecting mirror reflects the light emitted from the light source and diffused in a direction different from the direction of the light detecting means toward the light detecting means. This allows
Since the light reflected by the reflecting mirror is received on the light detecting means and the amount of light used for controlling the output of the light source can be increased, the output of the light source can be controlled with high accuracy.

Further, the invention is characterized in that the reflection mirror is a concave reflection mirror. According to the invention, the concave reflecting mirror reflects and focuses the light emitted from the light source and diffused in a direction different from the direction of the light detecting means toward the light detecting means. As described above, the light reflected while being focused by the concave reflecting mirror can be received on the light detecting means. Therefore, the decrease in the amount of light due to diffusion is small, and the amount of light used for output control of the light source is increased to increase the amount of light. The output can be controlled accurately.

Further, in the present invention, the light condensing means includes a converging lens for converging light emitted from the light source, and a reflecting mirror for reflecting the light converged by the converging lens toward the light detecting means. Features.

According to the present invention, the focusing lens focuses the light emitted from the light source and diffused in a direction different from the direction of the light detecting means, and the reflecting mirror reflects the focused light toward the light detecting means. As described above, the light reflected while being focused by the reflecting mirror can be received on the light detecting means. Therefore, the decrease in the amount of light due to diffusion is small, and the amount of light used for output control of the light source is increased to increase the light output Can be accurately controlled.

Further, the invention is characterized in that the condensing means includes first and second reflecting mirrors for reflecting light emitted from the light source toward the light detecting means.

According to the present invention, the first and second reflecting mirrors reflect light emitted from the light source and diffused in a direction different from the direction of the light detecting means toward the light detecting means. As described above, the light reflected by the first and second reflection mirrors is received on the light detecting means, and the amount of light used for the output control of the light source can be increased, so that the output of the light source can be controlled accurately. Will be possible.

Further, the present invention is characterized in that the first and second reflection mirrors are both concave reflection mirrors.

According to the present invention, the first and second concave reflecting mirrors reflect and focus the light emitted from the light source and diffused in a direction different from the direction of the light detecting means toward the light detecting means. As described above, the light reflected while being focused by the concave reflecting mirror can be received on the light detecting means. Therefore, the decrease in the amount of light due to diffusion is small, and the amount of light used for output control of the light source is increased to increase the amount of light. The output can be controlled accurately.

Also, in the present invention, the light condensing means includes a first converging lens for converging the light emitted from the light source, and a reflecting mirror for reflecting the light converged by the first converging lens toward the light detecting means. And a second focusing lens for converging light emitted from the light source and condensing the light on the light detecting means.

According to the present invention, the first focusing lens focuses the light emitted from the light source and diffused in a direction different from the direction of the light detecting means, and the reflecting mirror reflects the focused light toward the light detecting means. . The second focusing lens focuses the light emitted from the light source and diffused in the direction of the light detecting means. In this manner, the light that is reflected while being focused by the reflection mirror and the light that is focused by the second focusing lens can be received on the light detection means.
It is possible to control the output of the light source with high accuracy by increasing the amount of light used for the output control of the light source.

Further, according to the present invention, the light condensing means includes first and second converging lenses for converging light emitted from a light source,
Including a first reflecting mirror that reflects light focused by the first focusing lens toward the light detecting means and a second reflecting mirror that reflects light focused by the second focusing lens toward the light detecting means It is characterized by.

According to the present invention, the first and second focusing lenses focus light emitted from the light source and diffused in a direction different from the direction of the light detecting means, and the first reflecting mirror is focused by the first focusing lens. The light reflected by the second focusing mirror is reflected by the second reflecting mirror toward the light detecting means. As described above, since the light reflected while being focused by the first and second reflection mirrors can be received on the light detection means, the decrease in the amount of light due to diffusion is small, and the amount of light used for controlling the output of the light source is increased. Thus, the output of the light source can be controlled with high accuracy.

According to another aspect of the present invention, there is provided an optical pickup device for recording or reproducing information on or from an optical recording medium by light, a light source for emitting light, light detecting means for detecting light emitted from the light source, A light separating unit that separates a part of light emitted from the light source and that is to be used for recording or reproducing information and condenses the light on the light detecting unit, and a light emitting unit that emits light from the light source in response to an output from the light detecting unit. An optical pickup device characterized by including control means for controlling output.

According to the present invention, a signal based on the amount of light detected by the light detecting means is output, and the control means controls the light output emitted from the light source in response to the output signal. The light detection means can receive both light emitted from the light source and directly incident without being used for recording or reproduction of information and a part of light to be used for recording or reproduction of information. The amount of received light that can be used for control increases, and the accuracy of light output control can be improved. In addition, since light emitted from the light source and not used for recording or reproducing information is used for output control, light use efficiency can be improved.

Further, the present invention is characterized in that the light splitting means is a beam splitter having a light splitting surface formed so that the light reflectance is partially different.

According to the present invention, the beam splitter reflects a part of the light emitted from the light source and to be used for recording or reproducing information toward the light detecting means. This allows the light reflected by the beam splitter to be received on the light detecting means and the amount of light used for controlling the output of the light source to be increased, so that the output of the light source can be accurately controlled.

Further, according to the present invention, the light splitting surface formed so that the light reflectance of the beam splitter is partially different,
It is characterized by being formed by coating with coating materials having different reflectances.

According to the present invention, the light separating surface is formed so as to have a partially different light reflectance by coating a coating material having a different reflectance. As a result, it is possible to easily set a light separation surface having a partially different light reflectance, so that light used for controlling the output of the light source is extracted at a desired ratio from the light emitted from the light source. Can be.

Further, in the invention it is preferable that the light separating means further includes a converging lens for converging the light reflected by the beam splitter.

According to the present invention, since the light separating means includes the focusing lens, the light reflected and separated by the beam splitter is focused and incident on the light detecting means. This allows the light reflected by the beam splitter to be incident on the light detecting means without being reduced by diffusion, thereby further increasing the amount of light used for controlling the output of the light source, so that the output of the light source is accurately controlled. It becomes possible.

Further, according to the present invention, the light detecting means includes a photodiode as a light detecting element, a converting means for converting light detected by the photodiode into a current or voltage signal, and a signal converted by the converting means. Amplifying signal amplifying means, wherein the photodiode, the converting means and the signal amplifying means are integrated into a single component.

According to the present invention, the light detecting means is constituted by integrating the photodiode, the converting means and the signal amplifying means into a single component, which can contribute to the miniaturization of the optical pickup device.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system diagram of a main portion showing a simplified configuration of an optical pickup device 20 according to a first embodiment of the present invention. The optical pickup device 20 includes an optical recording medium for recording or reproducing information, a light source 21 for emitting light, a light detecting unit 22 for detecting light emitted from the light source 21, and a light detecting unit 22 for detecting information emitted from the light source 21. Light collecting means 23 for collecting light not used for recording or reproduction on the light detecting means 22; and control means 2 for controlling the output of light emitted from the light source 21 in response to the output from the light detecting means 22
4, light receiving means for receiving reflected light from the optical recording medium and reading information, and disposed between the optical recording medium and the light source 21 for condensing light emitted from the light source 21 onto the optical recording medium for optical recording. Condensing optical system 2 for condensing reflected light from a medium to light receiving means
5 is included.

The light source 21 is a semiconductor laser device 21, and a semiconductor laser chip 26 provided in the semiconductor laser device 21 emits light toward an optical recording medium. Most of the emitted light enters the condenser optical system 25 and is used for recording or reproducing information on or from an optical recording medium. Light that is not used for recording or reproducing information without entering the remaining light collecting optical system 25 diffuses.

The light detecting means 22 includes a photodiode,
It includes conversion means and signal amplification means. The photodiode is a photodetector, and receives and detects light emitted from the semiconductor laser chip 26 and diffused without being incident on the condensing optical system 25 (hereinafter, referred to as diffused light for convenience). The conversion means converts the light detected by the photodiode into a current or voltage signal. The signal amplifier amplifies the signal converted by the converter. Since the photodiode, the conversion means, and the signal amplification means are integrated into a single component, it is possible to contribute to miniaturization of the optical pickup device 20. Note that the photodiode, the conversion unit, and the signal amplification unit may be provided as individual components.

The control means 24 is an APC circuit 24.
A current signal (which may be a voltage signal) serving as a reference for controlling the output of the semiconductor laser chip 26 based on the amount of light required for recording or reproducing information on or from an optical recording medium is represented by AP
The information is set and stored in a memory provided in the C circuit 24 in advance. The APC circuit 24 includes the optical pickup device 2
The output of the semiconductor laser chip 26 is judged to be excessive or insufficient by comparing a current signal serving as a reference to be controlled according to the operation state of 0 with the current signal output from the light detecting means 22, and the driving of the semiconductor laser chip 26 is determined. A signal for controlling the current is supplied to the semiconductor laser device 21 and the output is controlled to be constant. The condensing means 23 is a reflection mirror 23, which is light of the diffused light which is diffused in a direction different from the direction of the light detecting means 22 and which does not enter the above-described condensing optical system 25 and records or reproduces information. Is reflected toward the light detecting means 22.

The light receiving means receives the reflected light from the optical recording medium and converts it into a current signal corresponding to the amount of light to obtain a reflected light detection signal. The condensing optical system 25 includes a collimator lens 27, a rising mirror, an objective lens, a condensing lens, and the like, condenses light emitted from the semiconductor laser chip 26 on an optical recording medium, and reflects the light from the optical recording medium. The light is focused on the light receiving means. The light receiving means is a semiconductor laser device 2
1 may be provided as a light receiving / emitting unit, or may be provided as an individual component separate from the semiconductor laser device 21.

Most of the light emitted from the semiconductor laser chip 26 enters the condensing optical system 25 and is used for recording or reproducing information on an optical recording medium. The diffused light in a direction different from the direction of the light detecting means 22 is reflected toward the light detecting means 22 by the reflection mirror 23 and received on the light detecting means 22 together with the diffused light in the direction of the light detecting means 22. The light received on the light detecting means 22 is detected by the photodiode and converted into a current signal by the converting means. The converted signal is amplified by the signal amplifier and output to the APC circuit 24.

The APC circuit 24 includes the optical pickup device 2
In accordance with the operation state of 0, a current signal which is set in advance and serves as a reference to be controlled is read from the memory, and the current signal output from the light detection means 22 is compared with the read current signal.
A signal for controlling the drive current of the semiconductor laser chip 26 based on the comparison result is given to the semiconductor laser device 21 by the APC circuit 24, and the output is controlled to be constant.

FIG. 2 is a system diagram of a main portion showing a simplified configuration of an optical pickup device 28 according to a second embodiment of the present invention. Optical pickup device 28 of the present embodiment
Is similar to the optical pickup device 20 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the focusing means 29 is a concave reflection mirror 29.

The concave reflecting mirror 29 is a reflecting mirror that converges and reflects the light incident on the concave surface. The diffused light in a direction different from the direction of the light detecting means 22 is incident on the concave surface of the concave reflecting mirror 29 and is reflected and focused toward the light detecting means 22. The light reflected while being focused and the diffused light in the direction of the light detecting means 22 are received on the light detecting means 22, and the obtained current signal is used for output control of the semiconductor laser chip 26.

FIG. 3 is a schematic system diagram showing a simplified configuration of an optical pickup device 30 according to a third embodiment of the present invention. Optical pickup device 30 of the present embodiment
Is similar to the optical pickup device 20 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the focusing means 31 is a focusing lens 3 for focusing the diffused light emitted from the semiconductor laser chip 26.
2 and a reflecting mirror 33 that reflects the light focused by the focusing lens 32 toward the light detecting means 22.

The diffused light in a direction different from the direction of the light detecting means 22 is focused by the focusing lens 32 and
3 is reflected toward the light detecting means 22. The light reflected while being focused and the diffused light in the direction of the light detecting means 22 are received on the light detecting means 22, and the obtained current signal is used for output control of the semiconductor laser chip 26.

FIG. 4 is a schematic system diagram showing a simplified configuration of an optical pickup device 34 according to a fourth embodiment of the present invention. Optical pickup device 34 of the present embodiment
Is similar to the optical pickup device 20 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the focusing means 35 includes first and second reflecting mirrors 36 and 37 for reflecting the light emitted from the semiconductor laser chip 26 toward the light detecting means 22.

The diffused light is transmitted to the first and second reflection mirrors 3.
6 and 37, the light is reflected toward the light detecting means 22. The reflected light is received on the light detection means 22,
The obtained current signal is used for output control of the semiconductor laser chip 26.

FIG. 5 is a system diagram showing a simplified configuration of an optical pickup device 38 according to a fifth embodiment of the present invention. Optical pickup device 38 of the present embodiment
Is similar to the optical pickup device 34 of the fourth embodiment, and the corresponding portions are denoted by the same reference characters and description thereof is omitted. It should be noted that the light collecting means 39 includes first and second concave reflecting mirrors 40 and 41.

The diffused light is reflected and focused by the first and second concave reflecting mirrors 40 and 41 toward the light detecting means 22, respectively. The reflected light is converged and received on the light detecting means 22 without reducing the light amount, and the obtained current signal is used for output control of the semiconductor laser chip 26.

FIG. 6 is a system diagram of a principal part showing a simplified structure of an optical pickup device 42 according to a sixth embodiment of the present invention. The optical pickup device 42 is similar to the optical pickup device 20 according to the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof will be omitted. It should be noted that the light condensing means 43 includes a first focusing lens 44 for focusing the diffused light emitted from the semiconductor laser chip 26,
A reflecting mirror 45 for reflecting the light focused by the first focusing lens 44 toward the light detecting means 22; and a light detecting means 2 for focusing the diffused light emitted from the semiconductor laser chip 26.
2 is included.

The diffused light in a direction different from the direction of the light detecting means 22 is focused by the first focusing lens 44 and reflected by the reflecting mirror 45 toward the light detecting means 22. Further, the diffused light in the direction of the light detecting means 22 is focused by the second focusing lens 46 and collected on the light detecting means 22. The light reflected by the reflection mirror 45 and the light focused by the second focusing lens 46 are received by the light detecting means 22 without reducing the light amount, and the obtained current signal is used for output control of the semiconductor laser chip 26. Is done.

FIG. 7 is a system diagram showing a simplified configuration of an optical pickup device 47 according to a seventh embodiment of the present invention. Optical pickup device 47 of the present embodiment
Is similar to the optical pickup device 20 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the light condensing means 48 includes first and second light sources for converging light emitted from the semiconductor laser chip 26.
The focusing lenses 49 and 50, the first reflection mirror 51 that reflects the light focused by the first focusing lens 49 toward the light detecting means 22, and the light focused by the second focusing lens 50 to the light detecting means 22. And a second reflecting mirror 52 that reflects the light toward the first mirror.

The diffused light is focused by the first focusing lens 49 and reflected by the first reflecting mirror 51 toward the light detecting means 22. The diffused light in a direction different from the diffused light is focused by the second focusing lens 50 and reflected by the second reflecting mirror 52 toward the light detecting means 22. The light reflected by the first and second reflecting mirrors 51 and 52 is received on the light detecting means 22 without reducing the light amount, and the obtained current signal is transmitted to the semiconductor laser chip 2.
6 is used for output control.

As described above, according to the first to seventh embodiments of the present invention, the light detecting means 22 is provided with the light which is directly used without being used for recording or reproducing information and the light collecting means 2.
3, 29, 31, 35, 39, 43, and 48, the light that is incident on the semiconductor laser chip 26 can be received and the amount of light used for controlling the output of the semiconductor laser chip 26 can be increased. Can be accurately controlled. Further, since diffused light emitted from the semiconductor laser chip 26 and not used for recording or reproducing information is used for output control, the amount of light emitted from the semiconductor laser chip 26 and used for recording or reproducing information is reduced. The light use efficiency can be increased without any problem.

FIG. 8 is a system diagram of a principal part showing a simplified structure of an optical pickup device 53 according to an eighth embodiment of the present invention. Optical pickup device 53 of the present embodiment
Is similar to the optical pickup device 20 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the optical pickup device 53 separates a part of the light that is emitted from the semiconductor laser chip 26 and enters the condensing optical system 25 and is used for recording or reproducing information, and collects the collected light on the light detecting means 22. The light separating means 54 is included.

The light separating means 54 is a beam splitter 54 having a light separating surface 55 formed so that the light reflectance is partially different. The light reflectance of the light separating surface 55 is determined within a range where the amount of light transmitted through the light separating surface 55 does not become less than the amount of light necessary for recording or reproducing information on the optical recording medium. The beam splitter 54 of the present embodiment reflects about 2% of the light incident on the central portion 56 of the light separating surface 55, and transmits about 98% of the remaining light incident on the portion other than the central portion 56. The central portion 56 is coated with a coating material such as a monolayer film of magnesium fluoride (chemical formula: MgF ₂ ), and the other portion than the central portion 56 is coated with a coating material having a multilayer structure in which materials having various refractive indexes are alternately arranged. Coated. As a result, the light separation surface 55 formed so that the light reflectance is partially different.
Can be easily set.

As described above, the light separation surfaces 55 having partially different light reflectivities are formed by coating with coating materials having different reflectivities. This makes it possible to easily set the light separation surface 55 having partially different light reflectivity, so that the light used to control the output of the semiconductor laser chip 26 from the light emitted from the semiconductor laser chip 26 At a desired ratio.

The light emitted from the semiconductor laser chip 26 toward the optical recording medium is approximately 2% of the light that has entered the beam splitter 54 and has entered the central portion 56 of the light separating surface 55.
Is reflected toward the light detecting means 22, and the remaining light that has entered the portion except the central portion 56 is transmitted toward the optical recording medium and used for recording or reproducing information. Light detection means 2
The diffused light in the two directions and the light reflected by the beam splitter 54 are received by the light detecting means 22, and the obtained current signal is used for output control of the semiconductor laser chip 26.

FIG. 9 is a system diagram showing a simplified configuration of an optical pickup device 57 according to a ninth embodiment of the present invention. Optical pickup device 57 of the present embodiment
Is similar to the optical pickup device 53 of the eighth embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the beam splitter 54 is provided with a condenser lens 58.

The condenser lens 58 is disposed between the light detecting means 22 and the beam splitter 54, and is provided integrally with the beam splitter 54. Semiconductor laser chip 2
6 is reflected by the beam splitter 54, and the reflected light is condensed by the condenser lens 58, so that the amount of light is not reduced by diffusion, and the light detected by the light detector 22 is not reduced. Is received on the light detecting means 22 together with the diffused light in the direction of. The obtained current signal is used for output control of the semiconductor laser chip 26.

Although the condenser lens 58 is provided integrally with the beam splitter 54, it may be provided separately from the beam splitter 54.

As described above, according to the eighth and ninth embodiments of the present invention, the light detecting means 22 detects the light emitted from the semiconductor laser chip 26 and directly incident without being used for recording or reproducing information. Since both light and a part of light to be used for recording or reproducing information can be received, the amount of light that can be used for light output control increases,
It is possible to improve the accuracy of the light output control. Further, since light emitted from the semiconductor laser chip 26 and not used for recording or reproducing information is also used for output control, the light use efficiency can be improved.

[0066]

As described above, according to the present invention, the light detecting means emits light emitted from the light source and directly incident without being used for recording or reproducing information and light diffusing in a different direction from the light detecting means. Alternatively, since part of light to be used for reproducing and recording information can be received, the amount of light that can be used for light output control increases, and the accuracy of light output control can be improved. Further, since the above-described light output control can be performed without reducing the amount of light emitted from the light source and used for recording or reproducing information, light use efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a main part system diagram showing a simplified configuration of an optical pickup device 20 according to a first embodiment of the present invention.

FIG. 2 is a main part system diagram showing a simplified configuration of an optical pickup device 28 according to a second embodiment of the present invention.

FIG. 3 is a main part system diagram showing a simplified configuration of an optical pickup device 30 according to a third embodiment of the present invention.

FIG. 4 is a main part system diagram showing a simplified configuration of an optical pickup device according to a fourth embodiment of the present invention.

FIG. 5 is a main part system diagram showing a simplified configuration of an optical pickup device 38 according to a fifth embodiment of the present invention.

FIG. 6 is a main part system diagram showing a simplified configuration of an optical pickup device according to a sixth embodiment of the present invention.

FIG. 7 is a main part system diagram showing a simplified configuration of an optical pickup device 47 according to a seventh embodiment of the present invention.

FIG. 8 is a main part system diagram showing a simplified configuration of an optical pickup device 53 according to an eighth embodiment of the present invention.

FIG. 9 is a main part system diagram showing a simplified configuration of an optical pickup device 57 according to a ninth embodiment of the present invention.

FIG. 10 is a simplified system diagram showing a configuration of a conventional optical pickup device 1.

FIG. 11 is a simplified system diagram showing the configuration of another conventional optical pickup device 17;

[Explanation of symbols]

20, 28, 30, 34, 38, 42, 47, 53, 5
7 Optical Pickup Device 21 Light Source 22 Light Detection Means 23, 29, 31, 35, 39, 43, 48 Condensing Means 24 Control Means 25 Condensing Optical System 26 Semiconductor Laser Chip 54 Light Separating Means

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Claims (13)

[Claims] 1. An optical pickup device for recording or reproducing information on or from an optical recording medium by light, a light source for emitting light, light detecting means for detecting light emitted from the light source, and light emitted from the light source. Light collecting means for collecting light not used for recording or reproduction of information on the light detecting means, and control means for controlling output of light emitted from the light source in response to output from the light detecting means. An optical pickup device, characterized in that: 2. The optical pickup device according to claim 1, wherein said condensing means is a reflection mirror for reflecting light emitted from a light source toward a light detecting means. 3. The optical pickup device according to claim 2, wherein the reflection mirror is a concave reflection mirror. 4. The light condensing means includes: a converging lens for converging light emitted from a light source; and a reflecting mirror for reflecting light converged by the converging lens toward a light detecting means. Claim 1
An optical pickup device as described in the above. 5. The optical pickup device according to claim 1, wherein said condensing means includes first and second reflecting mirrors for reflecting light emitted from a light source toward a light detecting means. 6. The optical pickup device according to claim 5, wherein each of said first and second reflection mirrors is a concave reflection mirror. 7. The light condensing means includes: a first converging lens for converging light emitted from a light source; a reflecting mirror for reflecting light converged by the first converging lens toward light detecting means; 2. The optical pickup device according to claim 1, further comprising a second focusing lens that focuses the emitted light and focuses the emitted light on a light detection unit. 8. The light condensing means includes: first and second converging lenses for converging light emitted from a light source; and a first reflection for reflecting light converged by the first converging lens toward a light detecting means. The optical pickup device according to claim 1, further comprising: a mirror; and a second reflecting mirror that reflects the light focused by the second focusing lens toward the light detection unit. 9. An optical pickup device for recording or reproducing information on or from an optical recording medium by light, a light source for emitting light, light detecting means for detecting light emitted from the light source, and light emitted from the light source. Light separating means for separating a part of the light to be used for recording or reproducing information and condensing the light on the light detecting means, and controlling the output of the light emitted from the light source in response to the output from the light detecting means An optical pickup device comprising: 10. The optical pickup device according to claim 9, wherein the light splitting means is a beam splitter having a light splitting surface formed so that a light reflectance is partially different. 11. The light splitting surface formed so that the light reflectance of the beam splitter is partially different, and is configured by coating each of coating materials having different reflectances.
0. The optical pickup device according to 0. 12. The apparatus according to claim 10, wherein the light separating unit further includes a focusing lens for focusing light reflected by the beam splitter.
Or the optical pickup device according to 11. 13. The photodetector includes a photodiode serving as a photodetector, a converter that converts light detected by the photodiode into a current or voltage signal, and a signal that amplifies a signal converted by the converter. And amplifying means, wherein the photodiode, the converting means and the signal amplifying means are integrated into a single component.
3. The optical pickup device according to any one of 2.