JPH07193274A - Optical equipment - Google Patents

Abstract

PURPOSE:To facilitate the leading-out of a signal for detecting the distance from an irradiation part, e.g. the leading-out of a servo signal for focusing control of light irradiation to the irradiation part. CONSTITUTION:The equipment is provided with the following; an irradiation part 2, an optical element 21 having a light emitting part 1 and a first light receiving part 41, at least a second light receiving part 42 and a third light receiving part 43 which put the optical element 21 between them and are arranged on both sides of the element 21, and a covergent means 3. The first light receiving part 41 is arranged in the vicinity of the light emitting part 1, and receives the return light LR of the emitted light from the light emitting part 1 which return light travels from the irradiation part 2 toward the light emitting part 1. The second light receiving part 42 and the third light receiving part 43 are arranged step-wise in the manner in which one of the distances between the light receiving surfaces of the parts 42, 43 and the irradiation part 2 is large and the other is small as compared with the distance between the light receiving surface of the first light receiving part 41 and the irradiation part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the position of an irradiated portion when the irradiated portion, for example, an optical recording medium such as an optical disk or a magneto-optical disk is irradiated with light and the return light reflected by the irradiated light is detected. The present invention relates to an optical device suitable for detection, for example, when detecting a focusing signal.

[0002]

2. Description of the Related Art In a conventional optical device, for example, an optical pickup for an optical disc drive such as a compact disc (CD) player or a magneto-optical disc drive, optical components such as a grating and a beam splitter are individually assembled, so that the entire device is constructed. There is a problem in that it becomes complicated, and the optical arrangement setting is complicated, resulting in poor mass productivity.

For example, an optical pickup device for an optical recording medium, for example, an optical disc, has a grating 52 for emitting light emitted from a light source 51 such as a semiconductor laser diode, as shown in FIG. The light is introduced into the beam splitter 53 via the beam splitter 53 and transmitted therethrough, and then is condensed by the objective lens 55 via the collimator lens 54 onto the recording portion of the optical disc of the optical recording medium 56.
In FIG. 7, an alternate long and short dash line c indicates from the light source 51 to the optical recording medium 56.
Shows the optical axis to.

The light reflected from the optical recording medium 56 is reflected by the beam splitter 53 via the objective lens 55 and the collimator lens 54, separated from the optical axis c, and the concave lens 57 and the cylindrical lens provided on the side. The light is focused on a detector 59 such as a photodiode (PD) through the lens 58 and detected.

As another optical device, for example, as shown in FIG. 8 showing an example of the structure of an optical pickup section of a reflection type optical scanning microscope, light emitted from a light source 51 is reflected by a beam splitter 53, The surface of the sample 60 is condensed and illuminated by the objective lens 55. 61 denotes a focal plane.
Then, the light reflected by the sample 60 is transmitted through the beam splitter 53 through the objective lens 55 and a detector is arranged at the confocal position, or a pinhole 62 is arranged and the light passing therethrough is arranged behind it. It is detected by the detector 59. At this time, as shown by the arrow s, the sample 60
The state of the sample surface can be detected by relatively scanning the stage (mounting table) on which is arranged or the irradiation beam.

In the above-mentioned conventional optical system of the pickup system, the reflected light is prevented from returning to the emission position, that is, the light source, and the beam splitter is arranged between the light source and the irradiated portion as described above. As disclosed in Japanese Unexamined Patent Publication No. 1-303638, a configuration such as arranging holograms is adopted, and reflected light, that is, return light to a light source is separated from an optical path toward an irradiated portion and received and detected. It is configured to lead to the light receiving portion. However, in this case, the amount of light received by the light receiving element becomes small, and further there is a problem in that the alignment is complicated, the accuracy is problematic, and the assembly and manufacturing are complicated.

Further, as disclosed in, for example, Japanese Unexamined Patent Publication No. 2-278779, when the above optical pickup device is hybridly assembled on the same semiconductor substrate such as Si, strict alignment accuracy is required. Become.

[0008]

SUMMARY OF THE INVENTION The present invention seeks to simplify the structure of an optical device such as an optical device of an optical pickup system, downsize the entire device, simplify manufacturing, and improve reliability. Further, the amount of light returned to the light receiving element, that is, the amount of received light, can be increased to improve the output, and thus to reduce the power of the light emitting light source and thus the power consumption.

Further, particularly in the present invention, it is possible to easily take out a signal for detecting the distance to the irradiated portion, for example, a servo signal for focusing control of light irradiation to the irradiated portion. To form the optical device.

[0010]

The first aspect of the present invention, as shown in the schematic configuration diagram of FIG. 1, shows a portion to be irradiated 2, a light emitting portion 1 and a light emitting portion 1 arranged in the vicinity of the light emitting portion 1. Return light L of the emitted light from the portion 1 from the irradiated portion 2 toward the light emitting portion 1
Optical element 21 having first light receiving section 41 for receiving _R
And at least the second and third light receiving portions 42 and 4 arranged on both sides of the optical element 21 with the optical element 21 interposed therebetween.
3 and converging means 3.

The second and third light receiving portions 42 and 43 are arranged such that the distance between the light receiving surfaces of these second and third light receiving portions 42 and the irradiated portion 2 is the irradiated portion 2 of the light receiving surface of the first light receiving portion 41.
In comparison with the distance between and, one is large and the other is small, that is, the steps are arranged.

The second aspect of the present invention, as shown in FIG. 2, is a schematic diagram showing an example of the structure of the irradiated portion 2, the light emitting portion 1, and the light emitted from the light emitting portion 1 which is disposed close to the light emitting portion 1. And an optical element 21 having a first light receiving portion 41 for receiving return light from the irradiated portion 2 toward the light emitting portion 1, and the optical element 21.
At least a second member disposed on both sides of the pin
And the third light receiving portions 42 and 43 and the converging means 3.

The emitted light from the light emitting portion 1 with respect to the arrangement direction of the first, second and third light receiving portions 41, 42 and 43 is incident on the irradiated portion 2 at an incident angle of 0 ° <α <90 °. Due to the arrangement relationship of incidence with α, that is, the light receiving portions 41, 4
The arrangement surfaces of 2 and 43 are arranged to be inclined with respect to the arrangement direction.

[0014]

In the configuration of the present invention, since the return light itself from the irradiated portion 2 toward the light emitting portion 1 is received and detected by the light receiving portion 41, the amount of return light received by the light receiving portion 41 is directed to the light emitting portion 1, for example. This can be made larger than the case where the return light is branched and received.

According to the first aspect of the present invention, as shown in FIG. 1 which is a schematic diagram of a return path of light emitted from the light emitting section 1 of the optical element 21 to the irradiated section 2, the irradiated section 2 is shown.
On the other hand, in the just-focused state, the return light is as the small return light spot SP ₁ that irradiates almost only the optical element 21 as shown by the solid line in FIG.
The light receiving sections 42 and 43 of are not irradiated with the returning light. In this way, for example, when the irradiated portion 2 is in a so-called under-focus state at a position away from the just focus position shown by the solid line, the returning light is strongly converged by the converging means 3 as shown by the chain line. As a result, the spot SP ₂ having a diameter larger than that of the spot SP _{1 is formed} on the light receiving surface of the optical element 21 due to the returning, so that almost only the first light receiving portion 41 and, for example, the second light receiving portion 42 in the figure in the lower position are shown. When the irradiated portion 2 is in the so-called overfocus state in which the irradiated portion 2 is at the front position shown by the broken line, the returning light is weakly converged by the converging means 3 as shown by the broken line. As a result of returning, almost only the first light receiving unit 41 and the third light receiving unit 43 in the upper position in the drawing can be irradiated with light.

Therefore, when the return light can be detected only from the first light receiving section 41, it means that it is in the just focus state, and the return light is detected from the first and second light receiving sections 41 and 42. When it is possible to detect, it is possible to detect the under-focus state, and when it is possible to detect the return light from the first and third light receiving portions 41 and 43, it is possible to detect the over-focus state. That is, the position of the irradiated portion 2 can be detected.

Further, according to the second aspect of the present invention, as shown in FIG. 2, since the irradiated portion 2 is inclined from the light emitting portion 1 to emit the emitted light, the irradiated portion 2 is irradiated with the emitted light. The return light of is incident on the light-receiving surface of each light-receiving portion with an inclination. That is, the returning light spot has an oval or elliptical shape, and basically, similar to the first aspect of the invention, the inclination can detect the positional relationship with the irradiated portion 2.

That is, also in this case, as shown in FIG. 2 which is a schematic path diagram regarding the return light of the light emission from the light emitting section 1 of the optical element 21 with respect to the irradiated section 2, the irradiated section 2
On the other hand, in the just-focused state, the return light is as the small return light spot SP ₁ that irradiates almost only the optical element 21 as shown by the solid line in FIG.
The light receiving sections 42 and 43 of are not irradiated with the returning light. In this way, for example, when the irradiated portion 2 is in a so-called under-focus state at a position away from the just focus position shown by the solid line, the returning light is strongly converged by the converging means 3 as shown by the chain line. As a result of returning, the spot SP ₂ having a larger diameter than the spot SP ₁ is eventually formed on the light receiving surface of the optical element 21,
At this time, since the arrangement surface of each light receiving portion is inclined with respect to the arrangement direction, almost only the first light receiving portion 41 and, for example, the second light receiving portion 42 in the lower position in the drawing should be irradiated. On the contrary, when the irradiated portion 2 is in the so-called overfocus state in which it is in the front position shown by the broken line, the return light is weakly converged and returned by the converging means 3 as shown by the broken line. The first light receiving portion 41 and the third light receiving portion 4 in the upper position are shown.
Only 3 can be illuminated.

Therefore, when the return light can be detected only from the first light receiving section 41, it means that it is in the just focus state, and the return light is detected from the first and second light receiving sections 41 and 42. When it is possible to detect the return light from all of the second and third light receiving sections 42 and 43, it is possible to detect that the camera is in the underfocus state. That is, the position of the irradiated portion 2 can be detected.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is, as shown in FIG. 1 or FIG. 2, an irradiated portion 2, a light emitting portion 1 and an irradiated portion 2 of light emitted from the light emitting portion 1 which is disposed in the vicinity of the light emitting portion 1. The optical element 21 having the first light receiving portion 41 for receiving the return light L _R from the light emitting portion 1 and the at least second and third optical elements 21 arranged on both sides of the optical element 21. The light receiving sections 42 and 43 and the converging means 3 are provided. The basic configuration of the device of the present invention will be described with reference to FIG.

First, the optical element 21 will be described.
The light emitting unit 1 and the first light receiving unit 41 of the optical element 21 are, for example, arranged in proximity to each other on the common substrate 9, and the light emitting unit 1
The first light receiving section 41 receives and detects the return light L _R itself to the light emitting section 1 due to the reflection at the irradiated section 2 caused by the irradiation of the emitted light L from the irradiated section 2.

According to the above-mentioned optical element 21, the return light received by the first light receiving section 41 is received by the area of the light emitting section 1 other than the emitting section.

In the example shown in FIG. 3, the irradiated portion 2 is an optical recording medium such as an optical disk, and the recording information recorded on the irradiated portion 2 as, for example, concave and convex pits is recorded by the light in this pit. This is a case where the present invention is applied to a reproducing pickup device for reading recorded information depending on the intensity of reflected light due to diffraction.

In this case, the light emitting section 1 and the first light receiving section 41
The converging means 3 is provided between the optical element 21 having the above and the irradiated portion 2 formed of the above-mentioned optical disc. Then, the converging means 3 converges and irradiates the emitted light from the light emitting portion 1 onto the irradiated portion 2, further converges the return light reflected from the irradiated portion 2, and the irradiated portion 2 of the converging means 3 The first light receiving unit 41 is arranged near the confocal point regarding the return light. With this configuration, the light emitted from the light emitting section 1 passes through coaxial paths before and after being reflected by the irradiated section 2 as shown by a chain line a in FIG.
The light receiving section 41 of the above is configured to receive light.

For example, the light received only by the first light receiving section 41 is converged to near the light diffraction limit, and at least a part of the light receiving surface of the first light receiving section 41 is within the light diffraction limit. , Where the wavelength of the light emitted from the light emitting portion 1 is λ and the numerical aperture of the converging means 3 is NA, the optical axis a of the light emitted from the light emitting portion 1 that crosses the arrangement reference plane S of the light receiving surface.
Should be provided at a position within 1.22λ / NA.

Further, in this case, the diameter φs of the light emitted from the light emitting portion 1 on the arrangement reference plane S of the light receiving surface of the first light receiving portion 41 is set to be smaller than the diameter φd of the light diffraction limit, and the light receiving portion 1 is effective. The light receiving surface is located outside the diameter φs of the emitted light. When a semiconductor laser is used as the light source of the light emitting unit 1, the diameter φs of the emitted light can be set to about 1 to 2 μm. On the other hand, the numerical aperture NA of the converging means 3 is, for example, 0.09.
.About.0.1, and the wavelength λ of the emitted light is about 780 nm,
The diffraction limit, that is, φd, is about 1.22λ / NA≈10 μm.

Then, the light emitting section 1 is arranged at one confocal position of the converging means 3. Specifically, the waist of the light emitted from the semiconductor laser is located at this focus position. Then, the irradiated portion 2 is positioned at the other focus of the converging means 3.

In this case, as described above, the optical element 21 in which the light emitting section 1 and the first light receiving section 41 are arranged close to each other on the common substrate 9 is constructed. In the optical element 21, for example, a compound semiconductor substrate is used as the substrate 9, a semiconductor laser is monolithically formed as a light source of the light emitting unit 1, and a photodiode, for example, as the first light receiving unit 41 is formed.

In the illustrated example, the light emitting section 1 is constituted by a horizontal cavity type semiconductor laser 8 as a light source and a reflecting mirror 7 for directing light emitted from the horizontal cavity type semiconductor laser 8 in a predetermined direction.

In the above-mentioned example, the case where the irradiated portion 2 is, for example, an optical disk has been described, but the optical device to which the present invention is applied is not limited to the above-mentioned example, and is, for example, a magneto-optical disk. It is also possible to use an optical pickup device that reads out a signal magnetically recorded on the disk by the Kerr effect. In this case, although not shown, for example, the polarizer is provided between the light emitting section 1 and the irradiated section 2, that is, on the optical path from the light emitting section 1 to the irradiated section 2 and the optical path reflected back from the irradiated section 2. On the other hand, a configuration is adopted in which the analyzer is arranged on the other hand, and the analyzer is arranged so as to face the first light receiving portion 41 at a position avoiding the optical path of the light emitted from the light emitting portion 1.

According to this structure, the light emitted to the magneto-optical disk of the irradiated portion 2 becomes the return light whose polarization plane is rotated by the Kerr effect according to the recorded information, so that it depends on the Kerr rotation angle. The amount of light passing through the analyzer changes. Therefore, if this is detected by the first light receiving unit 41,
Recording on the magneto-optical disk can be reproduced.

Further, the converging means 3 can have various structures such as a collimator lens structure.

The apparatus of the present invention has a basic structure having the above-mentioned optical element 21, as shown in FIGS. 1 and 2.
The second and third light receiving elements 4 are provided on both sides of the optical element 21.
Place 2 and 43.

An embodiment of the present invention will be described with reference to FIG. In this case, the basic configuration described above, that is, the irradiated portion 2
The optical element 21, the at least second and third light receiving portions 42 and 43 arranged on both sides of the optical element 21 with the optical element 21 interposed therebetween, and the converging means 3 are arranged. And the third light receiving portions 42 and 43 are such that the distance between these light receiving surfaces and the irradiated portion 2 is the first light receiving portion 41.
In comparison with the distance between the light receiving surface and the irradiated portion 2, one is large and the other is small, that is, they are arranged in a stepwise manner.

In this way, for example, when the irradiated portion 2 is in the just-focused state, the return light thereof is as a small return light spot SP ₁ which almost irradiates only the optical element 21 as shown by the solid line. The second and third light receiving portions 42 and 43 are prevented from being irradiated with return light. Then, for example, when the irradiated portion 2 is in a so-called under-focus state in a position away from the just focus position shown by the solid line, the returning light is strongly converged and returned by the converging means 3 as shown by the chain line. As a result, the spot SP _{1 is formed on} the light receiving surface of the optical element 21.
Since the spot SP ₂ has a larger diameter, almost only the first light receiving portion 41 and, for example, the second light receiving portion 42 in the figure at the lower position are irradiated, and vice versa.
In the so-called over-focus state, which is in the front position shown by the broken line, the returning light is weakly converged and returned by the converging means 3 as shown by the broken line, and as a result, the return light is almost at the first light receiving portion 41 and the upper position. In a certain figure, only the third light receiving portion 43 is irradiated.

Therefore, when the return light can be detected only from the first light receiving portion 41, it is in the just focus state, and the first light receiving portion 41 is irradiated from the irradiated portion 2 without performing any focusing adjustment. For example, reproduction output of information from the optical disk, that is, RF (high frequency) output can be taken out.

Then, when light is received by the second light receiving section 42 and an output is produced, it is possible to know that the irradiated section 2 is relatively far from the just focus position, and Focusing control using the output of the second light receiving section 42 as a focusing servo signal. For example, an actuator (not shown) provided in the pickup device automatically adjusts the distance between the irradiated section 2 and the focusing means, etc. Can be adjusted to. Further, when light is received by the third light receiving unit 43 and an output is generated, it is possible to know that the irradiated portion 2 is relatively closer to the just focus position, and at the same time, the second By using the output of the light receiving section 42 as a focusing servo signal, focusing control can be performed and position adjustment or the like can be automatically performed in a just focus state.

Also in the example of the device of the present invention shown in FIG. 2, the irradiated portion 2, the optical element 21, and at least the second and third light receiving portions arranged on both sides of the optical element 21 with the optical element 21 interposed therebetween. It comprises parts 42 and 43 and a converging means 3.

The emitted light from the light emitting portion 1 with respect to the arrangement direction of the first, second and third light receiving portions 41, 42 and 43 is incident on the irradiated portion 2 at an incident angle of 0 ° <α <90 °. Due to the arrangement relationship of incidence with α, that is, the light receiving portions 41, 4
The arrangement surfaces of 2 and 43 are arranged to be inclined with respect to the arrangement direction.

Even in this case, as shown in FIG. 2 which is a schematic path diagram regarding the return light of the light emitted from the light emitting section 1 of the optical element 21 with respect to the irradiated section 2, the irradiated section 2 is brought into a just focus state. In some cases, the return light is a small return light spot SP ₁ that irradiates almost only the optical element 21 as shown by the solid line, and the second and third light receiving units 4 are provided.
Almost no return light is applied to 2 and 43. Then, when the irradiated portion 2 is located away from the just focus position shown by the solid line, the returning light is strongly converged by the converging means 3 as shown by the chain line and returns, so that the optical element 21 receives light. Spot SP on the surface
The spot SP ₂ has a diameter larger than _1, but at this time, only the first light receiving portion 41 and the second light receiving portion 42 in the lower position in the figure are arranged by tilting the arrangement surface of each light receiving portion with respect to the arrangement direction. Irradiate. On the contrary, when the irradiated portion 2 is at the front position shown by the broken line, the returning light is weakly converged by the converging means 3 and returned as shown by the broken line, so that the first light receiving part 41 and the upper position are shown. In, only the third light receiving portion 43 is irradiated.

Therefore, also in the apparatus of the present invention shown in FIG. 2, the RF signal is detected by the first optical section 41, and the second optical section 41 is used.
And the output of the third light receiving portions 42 and 43 can detect the position of the irradiated portion 2, that is, whether the irradiated portion 2 is at the just focus position, or at a position farther or closer thereto. Also, focusing control can be performed with this detection output as in the case of FIG.

Next, an example of the optical element 21 in which the light emitting portion 1 and the photodiode PD constituting the first light receiving portion 41 are monolithically integrated on the common substrate 9 will be described with reference to FIGS. An example of the manufacturing method will be described.

As shown in FIG. 4A, the first conductivity type, for example, n
Each semiconductor layer constituting a semiconductor laser is epitaxially grown on a substrate 9 made of a GaAs substrate having a (100) crystal plane of the mold as a main surface. That is, for example, the first cladding layer 2 made of AlGaAs of the same conductivity type as that of the substrate 9 is sequentially formed.
2, an active layer 23 made of, for example, GaAs, a first clad layer 22, and a second clad layer 24 of a second conductivity type, for example, a p-type, which are different from each other, are sequentially epitaxially formed by MOCVD or the like to form a laminated semiconductor layer.

As shown in FIG. 4B, a part of these epitaxially grown semiconductor layers 24, 23 and 22 is left as a semiconductor laser LD, and at least finally the reflecting mirror 7 is left.
The portion for forming is etched by RIE or the like. The end surface of the semiconductor layer formed by this etching surface is used as one resonator end surface 28A of the semiconductor laser LD.
Similarly, the surface facing 8A is similarly etched by, for example, RIE to form the other resonator end surface 28B, and the horizontal resonator of the semiconductor laser is formed between both end surfaces 28A and 28B.
In this case, although not shown, a current blocking layer, that is, a current blocking region is formed by ion implantation of impurities or the like as described with reference to FIG. 5B.

Then, as shown in FIG. 4C, the mask layer 45 of the selective MOCVD, for example Si, is covered so as to cover the laminated semiconductor layer left on the substrate 9, that is, the constituent portion of the semiconductor laser LD.
For example, an insulating layer of O ₂ , SiN or the like is deposited.

As shown in FIG. 5A, a first semiconductor layer 46 made of, for example, GaAs of the first conductivity type, for example, n-type is selectively formed on the substrate 9 which is not covered with the mask layer 45.
It is formed by OCVD.

Subsequently, as shown in FIG. 5B, a second semiconductor layer 47 of GaAs of the second conductivity type, for example, p-type, is selectively formed by MOCVD, and the first and second semiconductor layers 46 and 47 are used to form a photo film. The diode PD is formed.

As shown in FIG. 5C, the mask layer 45 is removed by etching, and the semiconductor laser LD and the second semiconductor layer 4 are removed.
Electrodes 141 and 142 on one side of the semiconductor laser LD and the photodiode PD are ohmic-deposited on a part of the surface of the substrate 6, and a common electrode 143 is ohmic-deposited on the back surface of the substrate 9.

In this case, the resonator facet 28A of the semiconductor layer, in this example the first and second semiconductor layers 46 and 47, selectively epitaxially grown on the substrate 9 of FIG. 5B.
The surface 29 opposite to is the specified crystal plane. For example,
When the cavity length direction of the horizontal cavity of the semiconductor laser formed between the end faces 28A and 28B of the semiconductor laser, that is, the direction indicated by the arrow b in FIG. 5C is the [011] crystal axis direction, the facing surface 29 is { 111} A, and when the direction b is the [0-11] crystal axis direction, {1
11} B, the angle formed with the plate surface of the substrate 9 is 54.7 °. In addition, the direction b is [100]
When facing the crystal axis direction, the facing surface 29 is formed as {110}, and any angle of 45 ° with respect to the surface of the substrate 9 is formed as an inclined surface having a good morphology by an atomic surface. Then, if necessary, oblique vapor deposition of a reflective film on the slope, CV
The reflection mirror 7 is formed by performing D and the like.

Therefore, the light emitted from the end face 28A of the horizontal cavity of the semiconductor laser is reflected by the reflecting mirror 7 having the specified crystal plane formed in this way to a predetermined direction, for example, the vertical direction shown in FIG. Or the light can be emitted obliquely as shown in FIG. Further, according to this configuration, since the reflecting mirror 7 is formed by the crystal plane, it has excellent specularity, and the inclination thereof is accurately set.

In the example described with reference to FIG. 5, the photodiode PD is provided on the substrate 9 with an n-type semiconductor layer 46 of the same conductivity type as that thereof and a p-type semiconductor layer 47 of a conductivity type different from this. In the case of sequential epitaxial growth, in order to reduce the crosstalk between the photodiode PD and the semiconductor laser LD, after performing the steps shown in FIG.
As shown in FIG. 4, prior to the epitaxial growth of the semiconductor layers 46 and 47, a second conductivity type different from that of the substrate 9 such as p
It is also possible to adopt a configuration in which the semiconductor layer 48 of the type is epitaxially grown, and the semiconductor layers 46 and 47 constituting the photodiode PD are epitaxially grown through the epitaxial growth. Then, in this case, a part of the upper semiconductor layer 47 is etched to expose a part of the lower semiconductor layer 46 to the outside, and the electrode 144 is independently ohmic-deposited on the part of the photodiode PD. Both electrodes are led out independently, and the semiconductor layer 48
Is separated from the semiconductor laser LD.

In the above-mentioned example, the light emitting portion 1 and the light receiving portion 4 are formed side by side, but at the same time, the light emitting portion 1 is formed.
It is also possible to dispose the photodiode PD on the upper side and to form the first light receiving section 41 also with respect to this.

In the example described above, the optical element 2 having the light emitting portion 1 and the first light receiving portion 41 on the substrate 9, for example, the semiconductor substrate.
Although the first example and the manufacturing method thereof have been described, the photodiode forming the first light receiving portion 41 and the photodiode forming the second and third light receiving portions 42 and 43 are formed on the substrate 9 at the same time. Then, the second and third light receiving portions 42 and 43 can be formed monolithically together with the optical element 21. In this case, when the stepped structure as shown in FIG. 1 is formed, the step portion is processed in advance on the substrate 9 by etching or the like, and the separation trench is dug after the laminated semiconductor layer is formed. Can be taken.

As described above, according to the device of the present invention, it is possible to simply configure a pickup device for an optical recording medium, for example, which has the functions of position detection of the irradiated portion 2 and focusing servo. However, in the configuration of the present invention, the irradiated portion 2 of the optical element 21 for extracting the RF signal is, as described in FIG.
Before and after being reflected at, the optical axis thereof passes through coaxial paths as indicated by a chain line a, and at least the final return light is directly received toward the light emitting section 1 of the return light. Since the first light receiving portion 41 for detecting is provided, at least the first light receiving portion 41 can efficiently receive light.

Further, according to the configuration of the present invention, the irradiated portion 2
Since the outward path of light to the first light receiving section 41 and the return path of return light to the first light receiving section 41 are coaxial, at least the first light receiving section 41
With respect to the above, since it is not necessary to divide the return light from the optical path between the light emitting section 1 and the irradiated section 2 by a beam splitter or the like, not only can the number of optical components be reduced, but also the alignment can be simplified, As a result, it is possible to improve the precision, thereby simplifying the structure, simplifying the assembly and manufacturing, thereby improving the productivity, improving the reliability, and further reducing the size of the entire optical device.

Further, since the light emitting section 1 and the first to third light receiving sections are integrated on a common substrate, the mutual optical positional relationship can be set accurately, so that the precision can be improved. Therefore, the first light receiving section 41 can be arranged sufficiently close to the light emitting section 1 and, in this case, the first light receiving section 41 allows the light emitting section 1 to reach the light emitting section 1. The return light can be received more efficiently.

As described above, the light emitting section 1 is formed on the common substrate 9.
And the first first light receiving portion 41, the distance between them can be made sufficiently small, for example, about several μm. In this case, the returning light toward the light emitting portion 1 can be efficiently emitted. In addition to being able to receive light, setting of the positional relationship of each part such as alignment of the optical axis and the light receiving part can be configured accurately, reliably and in mass production.

However, in the apparatus of the present invention, in some cases, for example, the optical element 21 and the second and third light receiving portions 42 and 43 may be configured separately, so that a hybrid configuration is possible. However, various modifications such as a surface emitting laser may be used in the structure of the semiconductor laser.

[0059]

According to the above-mentioned device of the present invention, the position of the irradiated portion 2 can be detected, for example, focusing servo can be performed with a simple structure. Therefore, the irradiation target part 2 can be applied to, for example, an optical pickup device to simplify its configuration, reduce the size of the entire device, simplify manufacturing, and improve reliability.

Further, in the configuration of the present invention, in the optical element 21, the return light from the irradiated portion 2 toward the light emitting portion 1 is received and detected by the light receiving portion 41.
The amount of return light received by the optical receiver can be made larger than that in the case where the return light traveling toward the light emitting unit 1 is branched and received. Therefore, for example, it is applied to a pickup device for an optical recording medium to output its RF signal. That is, since the reproduction signal output can be increased, the S / N can be improved, the emission power can be reduced, and the power consumption can be reduced.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram of an example of an optical device according to the present invention.

FIG. 3 is a diagram showing a basic configuration of an optical device according to the present invention.

FIG. 4 is a process diagram (1) of an example of the manufacturing method of the device of the present invention. A is the one process drawing. B is the one process drawing. C is the one process drawing.

FIG. 5 is a process diagram (No. 2) of an example of the manufacturing method of the device of the present invention. A is the one process drawing. B is the one process drawing. C is the one process drawing.

FIG. 6 is a process drawing (3) of an example of a manufacturing method of the device of the present invention. A is the one process drawing. B is the one process drawing.

FIG. 7 is a schematic configuration diagram of an example of an optical device.

FIG. 8 is a schematic configuration diagram of another example of the optical device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting part 2 Irradiated part 3 Converging means 7 Reflector 21 Optical element 41 First light receiving part 42 Second light receiving part 43 Third light receiving part

Claims (2)

[Claims] 1. A radiated portion, a light emitting portion, and a first light emitting portion which is disposed in the vicinity of the light emitting portion and receives return light of the light emitted from the light emitting portion toward the light emitting portion from the light irradiated portion. An optical element having a light-receiving portion, at least second and third light-receiving portions arranged on both sides of the optical element, and a converging means. The distance between each light-receiving surface and the irradiated portion is selected such that one is large and the other is small compared to the distance between the light-receiving surface of the first light-receiving portion and the irradiated portion. An optical device characterized by. 2. An irradiation target part, a light emitting part, and a first light receiving part which is disposed in the vicinity of the light emitting part and receives return light of the light emitted from the light emitting part toward the light emitting part from the irradiation target part. An optical element having a light-receiving portion, at least second and third light-receiving portions arranged on both sides of the optical element, and a converging means. With respect to the arrangement direction of the light receiving portions of No. 3, the emitted light from the light emitting portion is 0 ° <α to the irradiated portion.
An optical device characterized in that the light is incident with an incident angle α of <90 °.