JPH05264338A - Light-sensing element device and light pickup apparatus - Google Patents

Abstract

PURPOSE:To facilitate regulation of optical components for monitoring the quantity of light of LD and to lessen the number of the components. CONSTITUTION:A light flux reflected by a beam splitter 3 is made to enter a light-sensing element unit 30. This light-sensing element unit 30 is constructed by embedding a light-sensing element 32 in a block 31 made of a transparent material and also by forming an incidence surface 33 thereof to be a convergence surface such as a spherical surface, a non-spherical surface, a cylindrical surface or a Fresnel lens surface. The light-sensing surface of the light-sensing element 32 is just opposed to the incidence surface 33. Accordingly, the light flux entering the light-sensing element unit 30 is converged by the incidence surface 33 and cast on the light-sensing surface of the light-sensing element 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light receiving element device and an optical pickup device.

[0002]

2. Description of the Related Art FIG. 15 shows an example of an optical pickup device for recording / reproducing / erasing data on a magneto-optical disk. In this case, the focusing error signal is detected by the astigmatism method, and the tracking error signal is detected by the push-pull method.

In FIG. 1, the light output from the semiconductor laser 1 is converted into parallel light by the collimator lens 2, then transmitted through the beam splitter 3, and the objective lens 4
And a fine spot is formed on the recording surface of the magneto-optical disk 5.

The reflected light from the magneto-optical disk 5 passes through the objective lens 4 again, is reflected by the beam splitter 3, is focused by the focusing lens 6, passes through the half-wave plate 7, and has its polarization plane of 45. After being rotated by one degree, it enters the polarization beam splitter 8 and is split by this polarization beam splitter 8 into an S polarization component and a P polarization component.

The P-polarized light component transmitted through the polarization beam splitter 8 is transmitted through the cylindrical lens 9 and then is incident on the four-division light receiving element 10. Further, the light flux of the S-polarized component reflected by the polarization beam splitter 8 is
The light is incident on the two-divided light receiving element 11.

The light beam reflected by the beam splitter 3 is focused by the focusing lens 12 and the semiconductor laser 1
Is incident on the light receiving element 13 for monitoring the output light amount of the. Here, the light receiving element 13 having a sufficiently small light receiving surface is used so that the light amount of the semiconductor laser 1 can be controlled at high speed.

As shown in FIG. 16A, the light receiving element 13 is fixed to a mounting member 14, and the housing 1 of the optical pickup device is mounted via the mounting member 14.
It is attached to 5. Alternatively, as shown in FIG. 3B, the mounting member 14 ′ formed in an L shape is attached to the housing 15.

Then, a focusing error signal of the objective lens 4 with respect to the recording surface of the magneto-optical disk 5 is obtained based on the light receiving signals respectively obtained from the four light receiving surfaces of the four-division light receiving element 10, and the two-division light receiving element 11 A tracking error signal of the spot with respect to the guide groove of the recording track formed on the magneto-optical disk 5 is formed based on the difference between the received light signals respectively obtained from the two light receiving surfaces.

Further, based on the difference between the sum of the light receiving signals obtained from the four light receiving surfaces of the four-divided light receiving element 10 and the sum of the light receiving signals obtained from the two light receiving surfaces of the two-divided light receiving element 11, A magneto-optical signal representing a reproduction signal from the user data area of the magnetic disk 5 is obtained,
Based on the sum of the light receiving signals obtained from the four light receiving surfaces of the four-divided light receiving element 10 and the light receiving signals obtained from the two light receiving surfaces of the two-divided light receiving element 11, respectively, A reproduction signal is obtained.

FIG. 17 shows an example of the control system of the semiconductor laser 1.

In the figure, the light receiving signal Pa output from the light receiving element 13 is converted into a corresponding voltage signal Va by the current / voltage converter 16, and this voltage signal Va is a comparison signal of the semiconductor laser drive controller 17. It is added to the input end. The reference voltage signal Vf output from the reference voltage generator 18 is applied to the reference signal input terminal of the semiconductor laser drive controller 17.

Semiconductor laser drive control voltage comparison circuit 17
Compares the voltage signal Va with the reference voltage signal Vf and controls the drive signal Dl applied to the semiconductor laser 1 so that the light emission amount of the semiconductor laser 1 becomes a predetermined value. The drive signal Dl is It is added to the drive circuit 19.

The modulation circuit 20 modulates the recording data WD output from a controller (not shown) by a predetermined modulation method to form a recording signal WS, and the recording signal WS is sent to the drive circuit 19. Has been added.

The drive circuit 19 drives the semiconductor laser 1 in response to the drive signal Dl, and when the recording signal WS is applied, records the drive level of the semiconductor laser 1 in accordance with the content of the recording signal WS. Change to a level.

As a result, the output light quantity of the semiconductor laser 1 is controlled to a predetermined value, and the output light quantity of the semiconductor laser 1 changes to the value at the time of recording in response to the recording signal WS.
Data is recorded on the magneto-optical disk 5.

[0016]

However, such a conventional device has the following disadvantages.

That is, the light receiving surface of the light receiving element 13 is made extremely small so that the light quantity of the semiconductor laser 1 can be controlled at high speed. For example, a light beam having a diameter of about 3 to 3 (mm) divided by the beam splitter 3 is used. Is focused to a diameter of 0.3 to 0.5 (mm) using the focusing lens 12. Therefore, first, the light receiving element 1 in the direction orthogonal to the optical axis
The influence of the positional deviation between the focusing lens 12 and the focusing lens 12 is large.

When the light receiving element 13 and the focusing lens 12 are displaced in the optical axis direction, the diameter of the light beam incident on the light receiving element 13 changes, so that the amount of light entering the light receiving element 13 changes. For example, if the diameter of the incident light flux changes to become larger than the light receiving surface of the light receiving element 13, the amount of light received by the light receiving element 13 decreases. On the contrary, if the diameter of the incident light beam becomes extremely small, the light receiving element 13 may not operate normally.

Further, the mounting member 14 is required for fixing the light receiving element 13 to the housing 15, and the same mounting member (not shown) is also required for fixing the focusing lens 12 to the housing 15. In addition, the number of parts around the focusing lens 12 and the light receiving element 13 is increased, and the adjustment work for preventing the above situation is complicated.

The present invention eliminates the above-mentioned disadvantages of the conventional device, reduces the number of parts around the focusing lens and the light receiving element, and reduces the work of adjusting the positions of the focusing lens and the light receiving element. The purpose is to provide a device.

[0021]

According to the present invention, an optical element having a focusing surface for focusing a light beam, a light receiving element for receiving the light beam focused by the optical element, and the optical element and the light receiving element are integrated. And a holding member for holding. The holding member is made of a transparent material, and the holding member and the optical element may be integrally molded. Further, the light receiving surface of the light receiving element may be arranged such that its normal line is inclined from a direction parallel to the optical axis of the optical element. Further, it is preferable that the emission surface of the holding member that directly emits the reflected light from the light receiving surface is formed as a scattering surface that scatters light. Further, a light absorbing material that absorbs light may be applied to the emission surface of the holding member that directly emits the reflected light from the light receiving surface.

Further, an optical element having a focusing surface for focusing the light beam, a light receiving element for receiving the light beam focused by the optical element, a holding member for integrally holding the optical element and the light receiving element, and An attachment member for attaching the holding member to the external fixing member is provided, and the optical element, the holding member, and the attachment member are integrally molded of a transparent material.

Further, a taper member which reflects the light beam incident from one opening portion on the inner wall surface and emits it from the other opening portion having a smaller diameter, a light receiving element which receives the light beam emitted from this taper member, and A taper member and a holding member that integrally holds the light receiving element are provided. Further, it is preferable that the holding member is made of a transparent material and is molded in such a manner that the taper member and the light receiving element are enclosed. The light receiving surface of the light receiving element may be arranged so that its normal line is inclined from a direction parallel to the central axis of the taper member. The taper member may be made of a transparent medium having a refractive index different from that of the holding member.

Further, a part of the luminous flux emitted from the semiconductor laser element is divided, the divided luminous flux is focused by an optical element and is incident on a light receiving element, and the above-mentioned semiconductor laser is used by using a light receiving signal obtained from this light receiving element. An optical pickup device for monitoring the output light amount of an element includes a holding member that integrally holds the optical element and the light receiving element.
The holding member is made of a transparent material, and the holding member and the optical element may be integrally molded. Further, the light receiving surface of the light receiving element may be arranged so that its normal line is inclined from a direction parallel to the optical axis of the optical element. Also,
The emission surface of the holding member that directly emits the reflected light from the light receiving surface may be formed as a scattering surface. Further, a light absorbing material that absorbs light may be applied to the emission surface of the holding member that directly emits the reflected light from the light receiving surface.

Further, a part of the luminous flux emitted from the semiconductor laser element is divided, the divided luminous flux is focused by the optical element and is incident on the light receiving element, and the above-mentioned semiconductor laser is used by using a light receiving signal obtained from this light receiving element. An optical pickup device for monitoring the output light amount of an element, comprising: a holding member that integrally holds the optical element and the light receiving element; and a mounting member that attaches the holding member to an external fixing member. The member and the mounting member are integrally molded of a transparent material.

Further, a part of the luminous flux emitted from the semiconductor laser element is divided, the divided luminous flux is focused by the optical element and is incident on the light receiving element, and the above-mentioned semiconductor laser is used by using a light receiving signal obtained from this light receiving element. In an optical pickup device for monitoring the output light amount of an element, a taper member which is emitted from the other opening having a smaller diameter and is incident on the light receiving element while reflecting the divided luminous flux incident from one opening on an inner wall surface, A holding member that integrally holds the taper member and the light receiving element is provided. Further, it is preferable that the holding member is made of a transparent material and is molded so as to enclose the taper member and the light receiving element. The light receiving surface of the light receiving element may be arranged so that its normal line is inclined from a direction parallel to the central axis of the taper member. The taper member may be made of a transparent medium having a refractive index different from that of the holding member.

[0027]

Therefore, since the light receiving element and the optical element are integrally held, the number of parts around the light receiving element and the optical element can be reduced, and the work for adjusting their positions can be reduced. Further, since the light receiving surface of the light receiving element is inclined with respect to the optical axis of the incident light beam or the incident direction of the light beam, it is possible to prevent the situation where the reflected light from the light receiving surface returns to the light source direction. Moreover, since the reflected light is scattered or absorbed, the influence of the reflected light can be further suppressed.

[0028]

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 as those of No. 5 and corresponding parts are given the same reference numerals.

In the figure, the light beam reflected by the beam splitter 3 is incident on the light receiving element unit 30. In this light receiving element unit 30, a light receiving element 32 is embedded in a block 31 made of a transparent material, and an incident surface 33 thereof is formed on a converging surface such as a spherical surface, an aspherical surface, a cylindrical surface, and a Fresnel lens surface. Is. The light-receiving surface of the light-receiving element 32 faces the incident surface 33.

Therefore, the light beam incident on the light receiving element unit 30 is focused by the incident surface 33, and the light receiving element 3
The light is incident on the two light receiving surfaces.

In this way, the light receiving element unit 30
Since the light-receiving element 32 and the incident surface 33 are integrally molded by the block 31, the light-receiving element 32 and an optical element for converging a light beam to the light-receiving element 32 (in this case, the incident surface 33). ) Is fixed.

Therefore, when assembling the optical pickup device, it is not necessary to adjust the position of the light receiving element 32 and the incident surface 33, and the workability in assembling the optical pickup device is improved. Further, since only one holding member for the light receiving element unit 30, which is conventionally required in this part, is required, the number of parts can be reduced.

By the way, the apparatus of FIG. 1 has the following disadvantages.

That is, as shown in FIG. 2, the light beam incident on the light receiving element unit 30 is reflected by the light receiving surface of the light receiving element 32 and emitted from the incident surface 33. Of the emitted light, the light flux that has passed through the beam splitter 3 is incident on the four-division light receiving element 10 and the two-division light receiving element 11,
An offset may appear in the focusing error signal and the tracking error signal, which may cause an inconvenience that accurate focusing servo control and tracking servo control are not performed.

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

In the figure, in the light receiving element 32 'embedded in the light receiving element unit 30, the normal line of its light receiving surface is
The direction of the light receiving surface is determined so as to form an elevation angle with respect to the direction parallel to the optical axis of the incident surface 33.

Therefore, as shown in FIG. 4, the light beam incident on the light receiving element unit 30 is reflected by the light receiving surface of the light receiving element 32 ′, and the reflected light is emitted from the side surface 30 a of the light receiving element unit 30.

As a result, the ambient light from the light receiving element unit 30 is divided into the four-divided light receiving element 10 and the two-divided light receiving element 1.
It is possible to prevent such a situation that the light beam is directly incident on the No. 1 beam.

Further, as shown in FIG. 5A, when the side surface 30a of the light receiving element unit 30 is formed as a scattering surface that scatters the reflected light from the light receiving element 32 ', disturbance light from the light receiving element unit 30 is generated. However, the four-division light receiving elements 10 and
It is possible to suppress the probability of incidence as flare light on the divided light receiving element 11.

Further, as shown in FIG. 3B, when the side surface 30a of the light receiving element unit 30 is coated with the light absorber 30b which absorbs the reflected light from the light receiving element 32 ', the light receiving element unit 30 receives light. It is possible to prevent ambient light from entering the four-division light receiving element 10 and the two-division light receiving element 11 as flare light.

FIG. 6 shows an optical system of an optical pickup device according to still another embodiment of the present invention. In the figure, the same parts as those in the embodiment of FIG. 3 and corresponding parts are designated by the same reference numerals.

In the figure, the light receiving element unit 30 'is provided with a mounting portion 34 for mounting the light receiving element unit 30' on the housing of the optical pickup device. Therefore, as shown in FIG. 7A, when this light receiving element unit 30 ′ is attached to the housing 15 of the optical pickup device, it can be directly screwed without using any other member. The number of parts can be further reduced. Further, as shown in FIG. 7B, when the surface of the housing 15 is parallel to the optical axis of the incident light beam, the mounting portion 34 may be provided on the surface facing the housing 15.

By the way, in the light-receiving element unit 30, as shown in FIG.
If the optical axis of is inclined, the focused light on the incident surface 33 does not enter the light receiving surface of the light receiving element 32, which is a disadvantage.

FIG. 9 shows an optical system of an optical pickup device according to still another embodiment of the present invention, which can solve such a problem. In the figure, the same parts as those in the embodiment of FIG. 1 and corresponding parts are designated by the same reference numerals.

In the figure, the light beam reflected by the beam splitter 3 is incident on the light receiving element unit 40. In the light receiving element unit 40, a block 41 made of a transparent material is provided with a light receiving element 42 and the other opening having a diameter corresponding to the light receiving surface of the light receiving element 42 while reflecting the light flux incident from one opening on the inner wall surface. The taper member 43 emitted from the part is embedded. Further, the light receiving surface of the light receiving element 42 faces the emission side opening of the taper member 43. Further, the taper member 43 can be made of a transparent material (light transmitting medium) having a refractive index different from that of the block 41, or a hollow portion.

Therefore, the light beam incident on the light receiving element unit 40 is converged while being reflected (or totally reflected) on the inner wall surface 43a of the taper member 43, emitted from the taper member 43, and incident on the light receiving surface of the light receiving element 42. To be done.

At this time, for example, as shown in FIG.
Even if the central axis of the taper member 43 is inclined with respect to the optical axis of the incident light beam, if the incident light beam is included inside the opening portion on the incident side of the taper member 43, the emission side opening portion of the taper member 43. The light flux emitted from the light incident on the light receiving surface of the light receiving element 42.

FIG. 11 shows an optical pickup device according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 9 are designated by the same reference numerals.

In the figure, in the light receiving element 42 'embedded in the light receiving element unit 40, the normal line of its light receiving surface is
The direction of the light receiving surface is determined so as to form an elevation angle with respect to the direction parallel to the central axis of the taper member 43.

Therefore, in this embodiment, the reflected light which is incident on the light receiving element unit 40 and is reflected by the light receiving surface of the light receiving element 42 'is further reflected by the bottom surface of the taper member 43, so that the light receiving element unit 40 is obtained. It is possible to prevent disturbance light from entering the four-division light receiving element 10 and the two-division light receiving element 11.

FIG. 12 shows an optical pickup device according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 9 are designated by the same reference numerals.

In the figure, the light receiving element unit 40 'is provided with a mounting portion 44 for mounting the light receiving element unit 40' on the housing of the optical pickup device. Therefore, as shown in FIG. 13A, this light receiving element unit 40 'is installed in the housing 15 of the optical pickup device.
When the optical pickup device is attached to the optical pickup device, the optical pickup device can be directly screwed without using any other member, so that the number of parts of the optical pickup device can be further reduced. Further, as shown in FIG. 7B, when the surface of the housing 15 is parallel to the optical axis of the incident light flux, the mounting portion 44 may be provided on the surface facing the housing 15.

FIG. 12 shows an optical pickup device according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 15 and corresponding parts are designated by the same reference numerals.

In the figure, the focusing lens 12 and the light receiving element 13 are integrally held by a holding member 50. Further, the holding member 50 is also formed with a mounting portion for fixing to the housing of the optical pickup device.

Therefore, since the positional relationship between the focusing lens 12 and the light receiving element 13 is fixed by the holding member 50, the adjustment work for adjusting the position between them is unnecessary. In addition, since the mounting portion is also formed on the holding member 50, the number of parts of the optical pickup device can be reduced. Further, since the parts used in the conventional device can be used as they are, the increase in the device cost can be suppressed.

By the way, although the present invention is applied to the optical pickup device used in the magneto-optical disk drive device in the above-mentioned embodiments, the present invention is similarly applied to other optical pickup devices. can do.

[0058]

As described above, according to the present invention,
Since the light receiving element and the optical element are integrally held, the number of parts around the light receiving element and the optical element can be reduced, and
The position adjustment work can be reduced. Further, since the light receiving surface of the light receiving element is inclined with respect to the optical axis of the incident light beam or the incident direction of the light beam, it is possible to prevent the situation where the reflected light from the light receiving surface returns to the light source direction. Further, since the reflected light is scattered or absorbed, the effect of being able to further suppress the influence of the reflected light is obtained.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram for explaining inconvenience of the light receiving element unit of FIG.

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

FIG. 4 is a schematic diagram for explaining the operation of the light receiving element unit of FIG.

FIG. 5 is a schematic view showing another example of the light receiving element unit.

FIG. 6 is a schematic diagram showing an optical system of an optical pickup device according to still another embodiment of the present invention.

FIG. 7 is a schematic diagram for explaining attachment of the light receiving element unit of FIG.

FIG. 8 is a schematic diagram for explaining inconvenience of the light receiving element unit of FIG.

FIG. 9 is a schematic diagram showing an optical system of an optical pickup device according to still another embodiment of the present invention.

FIG. 10 is a schematic diagram for explaining the operation of the light receiving element unit of FIG.

FIG. 11 is a schematic diagram showing an optical system of an optical pickup device according to still another embodiment of the present invention.

FIG. 12 is a schematic diagram showing an optical system of an optical pickup device according to still another embodiment of the present invention.

FIG. 13 is a schematic diagram for explaining attachment of the light receiving element unit of FIG.

FIG. 14 is a schematic diagram showing an optical system of an optical pickup device according to still another embodiment of the present invention.

FIG. 15 is a schematic diagram showing a conventional example of an optical system of an optical pickup device.

16 is a schematic diagram for explaining attachment of the light receiving element unit of FIG.

FIG. 17 is a block diagram showing an example of a control system of a semiconductor laser.

[Explanation of symbols]

 30, 40 Light receiving element unit 30a Scattering surface 30b Light absorber 31, 41 Block 32, 32 ', 42, 42' Light receiving element 33 Incident surface 34, 44 Mounting portion 43 Tapered member 43a Inner wall surface 50 Holding member

Claims (20)

[Claims] 1. An optical element having a focusing surface for focusing a light beam, a light receiving element for receiving the light beam condensed by the optical element, and a holding member for integrally holding the optical element and the light receiving element. A light-receiving element device characterized by the above. 2. The light-receiving element device according to claim 1, wherein the holding member is made of a transparent material, and the holding member and the optical element are integrally molded. 3. The light receiving surface of the light receiving element is arranged so that its normal line is inclined from a direction parallel to the optical axis of the optical element. Photodetector device. 4. The light-receiving element device according to claim 3, wherein an emission surface of the holding member that directly emits the reflected light from the light-receiving surface is formed as a scattering surface that scatters light. 5. The light-receiving element device according to claim 3, wherein a light-absorbing material that absorbs light is applied to the emission surface of the holding member that directly emits the reflected light from the light-receiving surface. .. 6. An optical element having a focusing surface for focusing a light beam, a light receiving element for receiving the light beam condensed by the optical element, a holding member for integrally holding the optical element and the light receiving element, and A light-receiving element device comprising a mounting member for mounting a holding member to an external fixing member, wherein the optical element, the holding member, and the mounting member are integrally molded with a transparent material. 7. A taper member which reflects a light beam incident from one opening portion on the inner wall surface and emits the light beam from the other opening portion having a smaller diameter, and a light receiving element which receives the light beam emitted from the taper member, A light-receiving element device comprising a taper member and a holding member that integrally holds the light-receiving element. 8. The light-receiving element device according to claim 7, wherein the holding member is made of a transparent material and is molded so as to enclose the taper member and the light-receiving element. 9. The light-receiving element device according to claim 7, wherein the light-receiving surface of the light-receiving element is arranged such that its normal line is inclined from a direction parallel to the central axis of the taper member. .. 10. The light-receiving element device according to claim 8, wherein the taper member is made of a transparent medium having a refractive index different from that of the holding member. 11. A semiconductor laser device, wherein a part of a light beam emitted from a semiconductor laser device is split, the split light beam is focused by an optical device and is incident on a light receiving device, and a light receiving signal obtained from this light receiving device is used. An optical pickup device for monitoring an output light amount of an element, comprising: a holding member that integrally holds the optical element and the light receiving element. 12. The holding member is made of a transparent material,
The optical pickup device according to claim 11, wherein the holding member and the optical element are integrally molded. 13. The light receiving surface of the light receiving element is arranged such that its normal line is inclined from a direction parallel to the optical axis of the optical element. The optical pickup device described. 14. The optical pickup device according to claim 13, wherein an emission surface of the holding member that directly emits the reflected light from the light receiving surface is formed as a scattering surface that scatters light. 15. The optical pickup device according to claim 13, wherein a light absorbing material that absorbs light is applied to an emission surface of the holding member that directly emits the reflected light from the light receiving surface. .. 16. A semiconductor laser device, wherein a part of a light beam emitted from a semiconductor laser device is split, the split light beam is focused by an optical device and is incident on a light receiving device, and a light receiving signal obtained from this light receiving device is used. An optical pickup device for monitoring the output light amount of an element, comprising: a holding member that integrally holds the optical element and the light receiving element; and a mounting member that attaches the holding member to an external fixing member. An optical pickup device, wherein the member and the mounting member are integrally molded of a transparent material. 17. A semiconductor laser device, wherein a part of a light beam emitted from a semiconductor laser device is split, the split light beam is focused by an optical device and is incident on a light receiving device, and a light receiving signal obtained from this light receiving device is used. In an optical pickup device for monitoring the output light amount of an element, a taper member which is emitted from the other opening having a smaller diameter and is incident on the light receiving element while reflecting the divided luminous flux incident from one opening on an inner wall surface, An optical pickup device comprising a holding member that integrally holds the taper member and the light receiving element. 18. The holding member is made of a transparent material,
The optical pickup device according to claim 17, wherein the taper member and the light receiving element are molded so as to be enclosed. 19. The optical pickup device according to claim 17, wherein the light-receiving surface of the light-receiving element is arranged such that its normal line is inclined from a direction parallel to the central axis of the taper member. .. 20. The optical pickup device according to claim 18, wherein the taper member is made of a transparent medium having a refractive index different from that of the holding member.