JP2001184709A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize the optical pickup device constituted to detect part of a laser beam emitted from a laser light emitting element and to make control to maintain the specified light quantity thereof while maintaining the high detection accuracy of the light quantity. SOLUTION: The optical pickup device including an optical system which irradiates the prescribed position of an optical disk 17 with the laser beam emitted from a semiconductor laser 11 via an objective lens 16 and a laser light quantity detecting means for detecting the light quantity of the laser beam emitted from the semiconductor laser 11 is constituted with the laser light quantity detecting means by a condenser mirror 18A which reflects the laser beam off the effective diameter of the objective lens in directions different with respect to the optical axis of the semiconductor laser 11 and a light quantity detecting element 13 which is arranged on the reflection optical axis of the condenser mirror 18A, receives the reflected light reflected by the condenser mirror 18A and detects the light quantity of the laser beam emitted from the semiconductor laser 11.

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 irradiating an optical disk with laser light, and more particularly to a control for keeping a constant light amount by detecting a part of laser light output from a laser light emitting element. The present invention relates to an optical pickup device configured to perform the operation.

[0002]

2. Description of the Related Art In recent years, as information recording / reproducing devices for personal computers and the like, devices such as CD-ROMs, CD-Rs, and CD-RWs using optical disks as recording media have been widely used. Each of these information recording / reproducing devices has a built-in optical pickup device. The optical pickup device irradiates a laser beam to an optical disk to record information, and detects information reflected from the optical disk to read information. Have been.

In this type of information recording / reproducing apparatus, it is necessary to keep the output level of a laser beam irradiated on an optical disk constant in order to perform stable recording / reproducing processing. For this reason, the optical pickup device has laser light amount detecting means for detecting the intensity of the laser light emitted from the semiconductor laser, and emits light from the semiconductor laser based on the intensity of the laser light detected by the laser light amount detecting means. The control is performed such that the intensity of the laser beam is always kept constant.

FIG. 7 is a schematic diagram showing an outward path system showing an example of a conventional optical pickup device. The optical pickup device is generally a semiconductor laser 1 (laser diode),
It comprises a beam splitter 2, a light amount detecting element 3, a collimator lens 4, a rising mirror 5, an objective lens 6, and the like. This optical pickup device performs recording / reproducing processing on the optical disk 7 by irradiating the optical disk 7 with a laser beam, and detecting and processing the reflected light.

[0005] Laser light (divergent light) emitted by the oscillation of the semiconductor laser 1 is incident on a beam splitter 2, and a part of the laser light is split by the beam splitter 2 and is incident on a light amount detection element 3. The light quantity detection element 3 outputs an output current corresponding to the light quantity of the incident laser light.

The output current output from the light quantity detecting element 3 is almost equal to the light quantity of the laser light which passes through the beam splitter 2 and irradiates the optical disk 7 via the collimator lens 4, the rising mirror 5, and the objective lens 6. Proportional. Therefore, by controlling the input current of the semiconductor laser 1 so that the light amount of the laser light incident on the light amount detection element 3 is constant, the light amount of the laser light irradiated on the optical disk 7 is stabilized at a constant light amount. Can be. As described above, the laser light amount detecting means is constituted by the beam splitter 2 and the light amount detecting element 3.

However, in the configuration of the optical pickup device (laser light amount detecting means) shown in FIG. 7, laser light emitted from the semiconductor laser 1 is split by the beam splitter 2 and guided to the light amount detecting element 3. Therefore, the light amount applied to the optical disk 7 is reduced by the light amount of the split laser light.

For this reason, a semiconductor laser 1 having a large amount of light is required, and an expensive semiconductor laser 1 is required. Also,
Since the semiconductor laser 1 with a large amount of light generates a large amount of heat, there is a problem that the cooling device is also increased in size.

In order to solve the problems of the optical pickup device shown in FIG. 7, an optical pickup device shown in FIG. 8 has been proposed. The optical pickup device shown in FIG. 1 does not use the beam splitter 2 in order to avoid a loss of light amount.

More specifically, the light quantity detecting element 3 is arranged at a position outside the effective diameter of the objective lens within the irradiation area of the laser light (divergent light) emitted from the semiconductor laser 1. The laser light outside the effective diameter of the objective lens does not irradiate the optical disk 7. Even if the laser light outside the effective diameter of the objective lens is incident on the light amount detection element 3, the light amount irradiating the optical disk 7 does not decrease. do not do.

[0011]

However, in the configuration shown in FIG. 8, it is necessary to dispose the light quantity detecting element 3 at a position far away from the optical axis connecting the semiconductor laser 1 and the collimator lens 4, which is inevitably required. There is a problem that the optical pickup device becomes large.

In addition, the configuration shown in FIG. 8 has a problem that the output current output from the light amount detection element 3 is weak, and there is a possibility that the light amount cannot be detected with high accuracy. This will be described with reference to FIG.

FIG. 9 shows the light intensity distribution of the laser light at the position where the light amount detecting element 3 is provided in the optical pickup device shown in FIG. As shown in FIG. 8, the optical pickup device shown in FIG. 8 utilizes the beam spread in the vertical direction (tangential direction on the disk surface) of the semiconductor laser 1 to generate laser light outside the effective diameter of the objective lens. The light amount is detected from the irradiation area.

However, as shown in the figure, the area of the light receiving section 9 for actually detecting the light amount is smaller than the area of the light amount detecting element 3, so that the light amount detecting area which can be detected by the light amount detecting element 3 is small. Becomes narrow. As a result, the output current output from the light amount detection element 3 becomes weak, and thus the output current is likely to change due to disturbance or the like, so that the light amount detection accuracy may be reduced.

The present invention has been made in view of the above points, and an object of the present invention is to provide an optical pickup device which can reduce the size of the device while maintaining high light amount detection accuracy.

Means for Solving the Problems To solve the above problems, the present invention is characterized by taking the following various means.

According to a first aspect of the present invention, there is provided an optical system for irradiating a laser beam emitted from a laser light emitting element to a predetermined position on a recording medium via an objective lens, and a light amount of the laser light emitted from the laser light emitting element. An optical pickup comprising a laser light amount detecting means for detecting the laser light amount, a reflecting mirror for reflecting the laser light outside the effective diameter of the objective lens in a different direction with respect to the optical axis of the laser light emitting element, A light amount detection element disposed on a reflection optical axis of the reflection mirror, receiving the light reflected by the reflection mirror, and detecting the light amount of the laser light emitted from the laser light emitting element. It is a feature.

According to a second aspect of the present invention, in the optical pickup according to the first aspect, the reflecting mirror has a curved reflecting surface for condensing the reflected light on a light receiving portion of the light quantity detecting element. It is characterized by the following.

Further, according to the third aspect of the present invention, the first aspect is provided.
In the optical pickup device described above, the reflection mirror is a plane mirror that changes an optical path of the reflected light toward a light receiving unit of the light amount detection element.

According to the fourth aspect of the present invention,
In the optical pickup device according to the aspect, a light-collecting lens that collects the light reflected by the reflection mirror to the light-receiving unit of the light-quantity detection element is provided between the light-receiving unit of the light-quantity detection element and the reflection mirror. It is characterized by the following.

According to a fifth aspect of the present invention, in the optical pickup according to the first or second aspect, a collimator lens for providing parallel laser light emitted from the laser light emitting element is provided in the optical system; The reflection mirror is provided between the laser light emitting element and the collimator lens.

Each of the means described above operates as follows.

According to the first aspect of the present invention, the reflecting mirror constituting the laser light amount detecting means reflects the laser light outside the effective diameter of the objective lens in a different direction with respect to the optical axis of the laser light emitting element. Therefore, unlike the configuration using the conventional beam splitter, without separating the laser beam,
That is, since the amount of laser light can be measured without reducing the amount of light applied to the recording medium, a laser light emitting element having a small output can be used.

Thus, the cost of the optical pickup device can be reduced. Further, the size of the cooling device for cooling the laser light emitting element can be reduced, and accordingly, the size of the optical pickup device can be reduced.

Further, the light quantity detecting element constituting the laser light quantity detecting means may be provided on the reflection optical axis of the reflection mirror, and the position at which the light quantity detection element is provided can be made flexible. Therefore, it is possible to easily dispose the light amount detection element at a position where the light reflected by the reflection mirror can be received and at a position where the size of the optical pickup device can be reduced.

According to the second aspect of the present invention, since the reflecting mirror is provided with a curved reflecting surface for condensing the reflected light on the light receiving portion of the light quantity detecting element, the reflected light enters the reflecting mirror. The reflected laser light can be efficiently incident on the light receiving unit. As a result, even if the size of the reflection mirror is reduced, a large output signal can be output from the light amount detection element, so that the light amount detection accuracy can be improved and the size of the optical pickup device can be reduced.

According to the third aspect of the present invention, since the reflecting mirror is constituted by a flat mirror for changing the optical path of the reflected light toward the light receiving portion of the light amount detecting element, the flat mirror has a curved reflecting surface. Since it is easier to manufacture than a reflecting mirror that has been manufactured, cost can be reduced. In addition, the reflective mirror having the curved reflecting surface eliminates the need for focusing between the curved reflecting surface and the light receiving unit, which is required,
It is possible to simplify the component design and the assembling work.

According to the fourth aspect of the present invention, the reflected light reflected by the reflection mirror is collected by the light receiving portion of the light quantity detecting element between the light receiving section of the light quantity detecting element and the reflecting mirror composed of a plane mirror. By providing the light collecting lens, much of the reflected light reflected by the reflecting mirror can be made incident on the light receiving unit. Therefore, even if a plane mirror is used as the reflection mirror, it is possible to improve the light amount detection accuracy.

According to the fifth aspect of the present invention, the reflection mirror is disposed between the laser light emitting element and the collimator lens, so that the reflection mirror is connected to the optical axis connecting the laser light emitting element and the collimator lens. Therefore, the optical pickup device can be disposed at a position close to the optical pickup device, and the size of the optical pickup device can be reduced.

[0029]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic structural view showing an optical pickup device 10A according to a first embodiment of the present invention. The optical pickup device 10A includes a semiconductor laser 11 (laser diode), which is a laser light emitting element, a collimator lens 14, a rising mirror 15, an objective lens 16, and a laser light amount detecting means.

The optical pickup device 10A irradiates the optical disk 17 with a laser beam, detects the reflected light, and performs processing on the reflected light.
The recording / reproducing process is performed on this.

The laser light (divergent light) emitted by the oscillation of the semiconductor laser 11 is applied to the collimator lens 14. The collimator lens 14 is a lens that converts the light passing therethrough into parallel light. Therefore, the laser light that is the divergent light emitted from the semiconductor laser 11 is
4, the light becomes parallel light. The collimated laser light is applied to the rising mirror 15.

The rising mirror 15 is formed by forming a total reflection film on one surface of a prism, and the reflection surface is inclined by 45 ° with respect to the optical axis of the semiconductor laser 1. Therefore, the laser light is converted into an optical path of 45 ° by the rising mirror 15 and is incident on the objective lens 16.

The objective lens 16 is provided with a focus mechanism and a tracking mechanism (not shown). Therefore, the laser beam is applied to a predetermined position on the optical disc 17 with a predetermined beam spot. At the time of reproduction, the light reflected by the optical disk 17 is detected by a light detecting means (not shown), and based on this, the information recorded on the optical disk 17 is reproduced.

Next, a description will be given of the laser light amount detecting means which is a main part of the present invention.

The laser light amount detecting means includes a light amount detecting element 13.
And a condenser mirror 18A (reflection mirror). The light amount detecting element 13 has a light receiving section 19 disposed therein. The light receiving unit 19 is, for example, an element such as a photodiode that can output an output current according to the amount of incident light.

The condensing mirror 18A has a mirror surface (a toric surface or the like) capable of condensing light by being curved into a concave spherical shape as shown in FIG. Part 20). The curved mirror section 20 is configured to reflect laser light outside the effective diameter of the objective lens in different directions with respect to the optical axis of the semiconductor laser 11.

More specifically, in this embodiment, as shown in FIG. 1B, when the optical pickup device 10A is viewed from the front, the upper position within the irradiation area of the laser beam and within the effective diameter of the objective lens. Is provided with a condenser mirror 18A.

Here, the laser light within the effective diameter of the objective lens and the laser light outside the effective diameter of the objective lens will be described with reference to FIG. FIG. 3A is a cross-sectional view taken along line X-X in FIG.
FIG. 3B shows a laser light irradiation area on the surface, and FIG. 3B shows the light intensity distribution.

As shown in FIG. 3A, the irradiation area of the divergent laser light is elliptical. The laser light irradiated on the optical disk 17 via the objective lens 16 in this irradiation area is a laser light in a region inside the effective diameter of the objective lens (a region indicated by a satin in FIG. 3A). The laser light in this area is referred to as a laser light within the effective diameter of the objective lens in this embodiment. The laser light region within the effective diameter of the objective lens is a laser light in an angle range indicated by an arrow θ in FIGS. 1A and 1B.

On the other hand, of the laser light irradiation area, the laser light in the area outside the laser light irradiation area within the effective diameter of the objective lens is directly recorded / recorded on the optical disk 17.
This is a laser beam not involved in the reproduction process. This laser light is referred to as a laser light outside the effective diameter of the objective lens in this embodiment. The present embodiment is characterized in that the condenser mirror 18A is provided in the laser beam irradiation area outside the effective diameter of the objective lens.

As described above, the laser beam outside the effective diameter of the objective lens is a laser beam that does not directly participate in the recording / reproducing processing on the optical disc 17. Therefore, even if the condenser mirror 18A is provided in the laser beam irradiation area outside the effective diameter of the objective lens, the light amount of the laser beam irradiated on the optical disk 17 does not decrease, and the recording / reproducing process is not performed. There is no effect.

In FIG. 3A, the area indicated by oblique lines is
The focusing mirror 18A is a region where the laser light is reflected.
Then, this region becomes a region (light amount detection region) where the light amount is incident on the element light receiving unit 13 described below and light amount detection is performed.

In this embodiment, the light amount detecting element 3 is not disposed directly in the laser beam irradiation area outside the effective diameter of the objective lens (see FIGS. 8 and 9) as in the prior art. A condensing mirror 18A is provided in an outside laser beam irradiation area. The condenser mirror 18A is a small component with respect to the light amount detection element 13, and the area of the curved mirror section 20 is larger than the light receiving area of the light receiving section 19.
Therefore, the curved mirror unit 20 can reflect the laser light in a wide area indicated by oblique lines in FIG.

On the other hand, the light quantity detecting element 13 is
8A is disposed on the reflected optical axis. At this time, as long as the light quantity detection element 13 is on the reflection optical axis of the condenser mirror 18A, there is no restriction on the arrangement position, and therefore, the arrangement position can be given a degree of freedom. Therefore, it is possible to easily arrange the light amount detection element 13 at a position where all the light reflected by the condenser mirror 18A can be received and at a position where the optical pickup device 10A can be downsized.

Further, as described above, the condenser mirror 18A has the curved mirror section 20, and the curved mirror section 20 detects the laser beam incident on the condenser mirror 18A by the light amount detecting element 1
The curvature is set so that light is condensed on the third light receiving unit 19.
Therefore, substantially all of the laser light that has entered and reflected the condenser mirror 18A. The light is incident on the light receiving unit 19 without waste.

As a result, even if the condenser mirror 18A is downsized, a large output signal can be output from the light quantity detecting element 13, thereby improving the light quantity detection accuracy and reducing the size and cost of the optical pickup device 10A. be able to. Further, since the size of the cooling device for cooling the semiconductor laser 11 can be reduced, the size of the optical pickup device 10A can also be reduced.

Further, since the size of the condensing mirror 18A can be reduced as described above, the condensing mirror 18A can be molded with resin and used in common with other structural members. In this case, the condensing mirror 18A can be used. Positioning and assembly are facilitated.

Further, in this embodiment, since the condensing mirror 18A is disposed between the semiconductor laser 11 and the collimator lens 14, the condensing mirror 18A can be used as a light connecting the semiconductor laser 11 and the collimator lens 14. It can be located close to the axis. Therefore, the focusing mirror 1
8A can be arranged compactly, and the size of the optical pickup device 10A can be reduced.

In this embodiment, a reflecting mirror is used to reflect laser light outside the effective diameter of the objective lens in different directions with respect to the optical axis of the laser light emitting element. However, the present invention is also applicable to a case where a reflection hologram is used as a means for reflecting a laser beam and as a condensing means for condensing light on a photodetector.

Next, a second embodiment of the present invention will be described.

FIG. 5 shows an optical pickup device 10B according to a second embodiment of the present invention. In FIG. 5,
The same components as those of the optical pickup device 10A according to the first embodiment described above with reference to FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof will be omitted.

In the optical pickup device 10A according to the first embodiment, as the reflecting mirror, the condensing mirror 18A having the curved mirror portion 20 (toric surface or the like) capable of condensing by curving into a concave spherical shape is used. The configuration was used.
On the other hand, the present embodiment is characterized in that the plane mirror 21 is used as the reflection mirror.

The plane mirror 21 is a mirror whose reflection surface 22 has a planar shape. Reflecting surface 2 having this planar shape
Reference numeral 2 denotes a semiconductor laser that emits laser light outside the effective diameter of the objective lens.
The light is reflected in different directions with respect to one optical axis. Specifically, when the optical pickup device 10B is viewed from the front as shown in FIG.
Reference numeral 1 denotes a plane mirror 21 disposed in a laser beam irradiation area and at an upper position within an effective diameter of the objective lens.

As described above, of the laser light irradiation area, the laser light outside the laser light irradiation area within the effective diameter of the objective lens does not directly participate in the recording / reproducing processing on the optical disk 17. Laser light (laser light outside the effective diameter of the objective lens). Therefore, even if the plane mirror 21 is arranged in the laser beam irradiation area outside the effective diameter of the objective lens, the light amount of the laser beam irradiated on the optical disk 17 does not decrease, and the recording / reproducing process is not affected. Does not affect

The flat mirror 21 is a small component with respect to the light amount detecting element 13, and the area of the reflection surface 22 is larger than the light receiving area of the light receiving section 19. Therefore, the reflection surface 2
1 can reflect laser light in a wider area outside the laser light irradiation area within the effective diameter of the objective lens. Therefore, the amount of light incident on the light receiving unit 19 can be increased, and the accuracy of detecting the amount of light can be improved.

On the other hand, the light quantity detecting element 13 is a flat mirror 2
It is arranged on one reflected optical axis. At this time, as long as the light quantity detecting element 13 is on the reflection optical axis of the plane mirror 21, there is no restriction on the arrangement position thereof, and thus the arrangement position can be given a degree of freedom. Therefore, also in the present embodiment, it is possible to easily arrange the light amount detection element 13 at a position where the light reflected by the plane mirror 21 can be received and at a position where the optical pickup device 10A can be downsized. Become.

Also in this embodiment, the plane mirror 2
1 is arranged between the semiconductor laser 11 and the collimator lens 14, the plane mirror 21 can be arranged at a position close to the optical axis connecting the semiconductor laser 11 and the collimator lens 14, and the optical pickup Apparatus 1
0A can be reduced in size.

Further, the plane mirror 21 used in this embodiment
Is easier to manufacture than the condenser mirror 18A having the curved mirror section 20 used in the first embodiment, so that the cost of the optical pickup device 10B can be reduced.
Further, in the present embodiment, it is not necessary to perform focusing between the curved mirror section 20 and the light receiving section 19, which is required when the condensing mirror 18A is used. it can.

Since the laser light emitted by the oscillation of the semiconductor laser 1 is divergent light, when the plane mirror 21 is used as the reflecting mirror, the reflected light also becomes divergent light. Therefore, the reflected light also enters the light receiving unit 19 of the light amount detecting element 13 in a divergent state, but the reflectance of the plane mirror 21 is changed, and the gain of the processing circuit that processes the output from the light receiving unit 19 is changed. For example, the influence of the divergence of the reflected light can be reduced.

FIG. 6 shows a modification of the optical pickup device 10B according to the second embodiment. In the present modification, the light reflected by the plane mirror 21 is reflected between the light receiving section 19 of the light amount detection element 13 and the plane mirror 21 by the light receiving section 1.
9 is provided with a condenser lens 23 for condensing light.

The focal length of the condenser lens 23 is set so that the light reflected by the plane mirror 21 is focused on the light receiving section 19 of the light quantity detecting element 13. Therefore, much of the divergent light reflected by the plane mirror 21 can be made incident on the light receiving section 19, and therefore, even if the plane mirror 21 is used as the reflection mirror, the light quantity detection accuracy can be improved. .

In each of the above embodiments, the condensing mirror 18A
Further, the plane mirror 21 is disposed between the semiconductor laser 11 and the collimator lens 14. However, if there is a margin in the arrangement position of the condenser mirror in the optical pickup device, it is also possible to arrange the condenser mirror above the collimator lens 14.

Specifically, taking the first embodiment as an example,
It is also possible to dispose the condenser mirror 18B at a position indicated by a dashed line in FIG. Further, the condenser mirror 18A and the flat mirror 21 can be raised from the collimator lens 14 and the condenser mirror 18 can be arranged closer to the mirror 15.

In each of the above-described embodiments, as shown in FIGS. 1A and 5A, the position where the light quantity detecting element 13 is disposed depends on the optical axis of the laser light incident on the light quantity detecting element 13. The optical axis of the laser light emitted from the semiconductor laser 11 is selected at a position substantially orthogonal to the optical axis.

However, the arrangement position of the light quantity detecting element 13 is not limited to this position, and as shown in FIG. 4 (the configuration of the first embodiment is taken as an example), the condensing mirror 18C ( By changing the direction of the plane mirror 21), it can be arranged at an arbitrary position.

[0067]

According to the present invention as described above, the following various effects can be realized. According to the first aspect of the present invention, since the amount of laser light can be measured without reducing the amount of light applied to the recording medium, a laser light emitting element having a small output can be used. Accordingly, the cost of the optical pickup device can be reduced, and the size of the cooling device for cooling the laser light emitting element can be reduced, and the size of the optical pickup device can be reduced.

Also, since the arrangement position of the light quantity detecting element can be given a degree of freedom, the light quantity detecting element can be arranged at a position where all the reflected light reflected by the reflecting mirror can be received. A strong output signal can be output.

According to the second aspect of the present invention, since the reflecting mirror is provided with a curved reflecting surface for condensing the reflected light on the light receiving portion of the light quantity detecting element, the reflected light is incident on the reflecting mirror and reflected. Almost all of the laser light can be made to be incident on the light receiving portion without waste, thereby improving the light amount detection accuracy and miniaturizing the optical pickup device.

According to the third aspect of the present invention, the cost can be reduced because the flat mirror is easier to manufacture than the reflecting mirror having the curved reflecting surface, and the curved mirror can be manufactured. In the case of a reflecting mirror having a reflecting surface, it is not necessary to focus the curved reflecting surface and the light receiving unit, which is required. Therefore, it is possible to simplify the component design and the assembling work.

According to the fourth aspect of the present invention, much of the reflected light reflected by the reflecting mirror can be made incident on the light receiving portion, so that even if a flat mirror is used as the reflecting mirror, the accuracy of light quantity detection can be improved. Can be achieved.

According to the fifth aspect of the present invention, the reflection mirror can be arranged at a position close to the optical axis connecting the laser light emitting element and the collimator lens, so that the size of the optical pickup device can be reduced.

[Brief description of the drawings]

FIGS. 1A and 1B are main configuration diagrams of an optical pickup according to a first embodiment of the present invention, wherein FIG. 1A is a plan view and FIG. 1B is a front view.

FIG. 2 is a perspective view of a condenser mirror provided in the optical pickup according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining a light amount detection area in the optical pickup according to the first embodiment of the present invention.

4A and 4B are main part configuration diagrams of a modified example of the optical pickup shown in FIG. 1, in which FIG. 4A is a plan view and FIG. 4B is a front view.

FIGS. 5A and 5B are main part configuration diagrams of an optical pickup according to a second embodiment of the present invention, wherein FIG. 5A is a plan view and FIG. 5B is a front view.

FIG. 6 is a main part configuration diagram of a modified example of the optical pickup shown in FIG. 5;

FIG. 7 is a configuration diagram of a main part of an optical pickup as an example of the related art (part 1).

FIG. 8 is a configuration diagram of a main part of an optical pickup as an example of the related art (part 2).

9 is a diagram for explaining a light amount detection area in the optical pickup shown in FIG.

[Explanation of symbols]

 10A Optical Pickup Device 11 Semiconductor Laser 13 Light Amount Detector 14 Collimator Lens 15 Startup Mirror 16 Objective Lens 17 Optical Disk 18A-18C Condensing Mirror 19 Light Receiving Unit 20 Curved Mirror 21 Flat Mirror 22 Flat Reflecting Surface 23 Condensing Lens

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeharu Honda 3-7-3 Nakamachi, Musashino-shi, Tokyo F-term in Tac Corporation (reference) 2H042 DA20 DB08 DB14 DD09 DE00 5D119 AA01 BA01 HA13 JA02 JA57 JA70 LB05

Claims (5)

[Claims] 1. An optical system for irradiating a laser beam emitted from a laser light emitting element to a predetermined position on a recording medium via an objective lens, and a laser light quantity detection detecting a light quantity of the laser light emitted from the laser light emitting element. An optical pickup device comprising: a reflecting mirror that reflects the laser light amount outside the effective diameter of the objective lens in a different direction with respect to an optical axis of the laser light emitting element; An optical pickup provided on an optical axis and configured to receive a light reflected by the reflection mirror and to detect a light amount of laser light emitted from the laser light emitting element; apparatus. 2. The optical pickup device according to claim 1, wherein the reflection mirror has a curved reflection surface for condensing the reflected light on a light receiving portion of the light quantity detection element. apparatus. 3. The optical pickup device according to claim 1, wherein the reflection mirror is a plane mirror that changes an optical path of the reflected light toward a light receiving portion of the light amount detection element. 4. The optical pickup device according to claim 3, wherein: between the light receiving section of the light amount detection element and the reflection mirror.
An optical pickup device, further comprising a condenser lens for condensing the light reflected by the reflection mirror on a light receiving portion of the light amount detection element. 5. The optical pickup device according to claim 1, wherein the optical system is provided with a collimator lens that converts laser light emitted from the laser light emitting element into parallel light, and the reflection mirror is provided. Is disposed between the laser light emitting element and the collimator lens.