JPH0831005A - Integrated optical unit - Google Patents

Abstract

PURPOSE:To facilitate position adjustment of respective optical parts and to obtain an integrated optical unit having good environmental resistance by packaging the optical parts on the surface of a substrate for packaging consisting of a silicon wafer having (110) as its uppermost surface by positioning the optical parts respectively in their optical axis direction in perpendicular grooves formed with {111} as their side faces. CONSTITUTION:This optical unit has the substrate 400 for packaging which consists of the silicon wafer 401 having (110) as its uppermost surface and having the perpendicular grooves 405, 406, 407 with the {111} faces as their side faces. The optical unit has a semiconductor laser 101 which is surface-packaged by positioning the laser in, at least, the optical axis direction and emits a luminous flux, a photodetector 111 which receives the return light from an optical recording medium 105 and a forward and backward path separating element 201 which introduces the luminous flux from the semiconductor laser 101 to the optical recording medium 105 side and introduces the return light from the medium 105 to the photodetector 111 side in the perpendicular grooves 405, 406, 407. As a result, the integrated optical unit which facilitates the position adjustment of the optical parts, is reduced in size and thickness and has the excellent environmental resistance is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated optical unit used in an optical recording medium, particularly an optical recording medium device for recording / reproducing information on / from a magneto-optical recording medium.

[0002]

2. Description of the Related Art As a conventional optical head, for example, FIG.
4 has been proposed. This optical head records / reproduces information on / from a magneto-optical recording medium. A linearly polarized divergent light beam from a semiconductor laser 101 is made incident on a polarizing beam splitter 102, and a polarizing film formed on a joint surface thereof. The light flux reflected by 103 passes through the objective lens 104 and the information track 10 of the magneto-optical recording medium 105.
Irradiation on 6 as a minute spot. The polarizing film 103 of the polarization beam splitter 102 has a characteristic that a vibration component (s-polarized light) in a direction perpendicular to the paper surface is reflected by 60 to 90%, and a vibration component (p-polarized light = signal component) in the paper surface is transmitted by almost 100%. As described above, the linearly polarized light from the semiconductor laser 101 is s-polarized and is formed by the dielectric multilayer film.
It is designed to enter 3.

The return light reflected by the magneto-optical recording medium 105 and having its polarization plane rotated ± θk around the optical axis according to the recorded information is incident on the polarization beam splitter 102 again as a convergent beam through the objective lens 104. , The polarizing film 10
After passing through 3, the light is spatially separated from the forward path and enters the multi-image prism 107. Multi-image prism 1
07 is configured by joining a first triangular prism 108 and a second triangular prism 109 each made of a birefringent crystal, and the optical axis of the first triangular prism 108 on which the return light first enters is the magneto-optical In order to detect a signal (hereinafter referred to as MO signal) by a differential method, the signal is set to be perpendicular to the optical axis of the returning light and inclined by 45 ° in the direction perpendicular to the paper surface,
The optical axis of the second triangular prism 109 is set to be inclined, for example, by 45 ° in the direction perpendicular to the optical axis with respect to the optical axis of the first triangular prism 108. Therefore, the return light that has entered the multi-image prism 107 is substantially split into three light beams and emitted from the multi-image prism 107.

The three beams emitted from the multi-image prism 107 pass through a toric lens 110 and a photodetector 11
Incident on 1. The toric lens 110 has a concave lens function of extending the focal length of transmitted light and a cylindrical lens function of generating astigmatism for detecting a focus error signal (hereinafter referred to as FES). In addition, the photodetector 11
As shown in FIG. 15, reference numeral 1 has three light receiving portions 112, 113 and 114 for separating and receiving three light fluxes having astigmatism, and the central light receiving portion 114 is a four-division light receiving area. The MO signal is detected based on the difference between the outputs of the light receiving units 112 and 113, and the FES is detected based on the difference between the outputs of the diagonal light receiving regions of the light receiving unit 114. Although not shown, the tracking error signal (hereinafter referred to as TES) can be detected by, for example, a push-pull (hereinafter referred to as PP) method.

[0005]

However, in the above-mentioned conventional optical head, since the number of parts is large,
The integrated value of the error of each component becomes large. Therefore, in order to absorb the error, for example, the photodetector 111
Xyz axis adjustment, or adjustment in the three axis directions such as xy axis adjustment of the photodetector 111 and z axis adjustment of the toric lens 110 is indispensable. Moreover, the xy-axis adjustment and the z-axis adjustment are not independent of each other and interfere with each other, which requires repeated adjustments, resulting in a great increase in the number of steps.

Further, since the number of parts is large, the mounting dimension of the portion indicated by the chain double-dashed line in FIG. 14 is as large as several tens to several hundreds of mm due to the securing of the space occupied by the parts and its adjusting mechanism. In mounting, there is a problem that an expensive housing divided into blocks of several points that requires complicated processing is required.

Further, since the light emitting surface of the semiconductor laser 101 and the light receiving surface of the photodetector 111, which are in an optically conjugate positional relationship with each other, are spatially widely separated from each other, they are vulnerable to temperature changes and aging changes. There is a problem that it is difficult to maintain the environment resistance characteristics. In addition, in order to solve this problem, there arises a problem that a large and more expensive housing for holding the optical system is required.

The present invention has been made by paying attention to the above-mentioned conventional problems, and it is possible to easily adjust the position of an optical component, and to make it compact, thin, inexpensive, and environmentally resistant. An object is to provide a mold optical unit.

[0009]

In order to achieve the above object, the first invention is an integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium. A mounting substrate formed of a (110) silicon wafer having an uppermost surface and having a vertical groove or a vertical wall having {111} as a side surface, and at least the optical axis direction in the vertical groove or the vertical wall of the mounting substrate. Positioned and surface-mounted, a semiconductor laser that emits a light flux, a photodetector that receives return light from the optical recording medium, and a light flux from the semiconductor laser is guided to the optical recording medium side,
And a round-trip path separating element for guiding the return light from the optical recording medium to the photodetector side.

A second invention is an integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium, wherein at least the uppermost surface is (100).
Mounting substrate made of a silicon wafer having a pyramidal groove having a side surface of {111}, and a semiconductor laser emitting a light beam, which is surface-mounted in the pyramidal groove of the mounting substrate at least in the optical axis direction. A photodetector that receives the return light from the optical recording medium, and a reciprocal that guides the light beam from the semiconductor laser to the optical recording medium side and guides the return light from the optical recording medium to the photodetector side. And a road separation element.

Further, a third invention is an integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium, which comprises a polyimide film having substantially vertical grooves formed on its uppermost surface. A mounting substrate having, the vertical groove of the mounting substrate, at least surface-positioned in the optical axis direction, the semiconductor laser emitting a light beam, a photodetector for receiving the return light from the optical recording medium, and It is characterized in that it has a reciprocal path separating element for guiding the light flux from the semiconductor laser to the optical recording medium side and guiding the return light from the optical recording medium to the photodetector side.

[0012]

In the first aspect of the invention, the semiconductor laser, the photodetector and the reciprocating path separating element are provided on the surface of the mounting substrate made of a silicon wafer having (110) as the uppermost surface, {11
1} is positioned in at least the optical axis direction and surface-mounted in a vertical groove or a vertical wall formed with side faces 1}.

Further, in the second invention, the semiconductor laser, the photodetector and the round-trip path separating element have a (100) uppermost surface on the surface of a mounting substrate made of a silicon wafer and a {111} side surface. Each of the formed pyramidal grooves is surface-mounted by being positioned at least in the optical axis direction.

Further, in the third invention, the semiconductor laser, the photodetector, and the round-trip path separating element are each provided at least in the optical axis in substantially vertical grooves formed on the surface of the mounting substrate having the polyimide film on the uppermost surface. Directionally positioned and surface mounted.

[0015]

FIG. 1 shows the basic structure of an optical system of an optical recording medium device in which an integrated optical unit according to the present invention is used. A portion surrounded by a chain double-dashed line is a non-common optical path of a reciprocating path. 1 shows an integrated optical unit having a semiconductor laser 101 forming a laser beam, a photodetector 111 for signal detection, and a round-trip path separation element 201. In the outward path, which is the imaging optical path,
The light beam emitted from the semiconductor laser 101 is reflected by the round-trip path separation element 201, and then imaged as a minute spot on the magneto-optical recording medium 105 by the objective lens 104.

In the return path, which is the signal detection optical path, the return light reflected by the magneto-optical recording medium 105 is the objective lens 1.
After passing through 04, the light enters the reciprocal path separation element 201 again, and the transmitted light is spatially separated from the forward path, and the photodetector 111
To the FE, and based on the output of this photodetector 111,
S, TES, MO signals are detected.

Here, the round-trip path separating element 201 is a semi-transparent plate or a semi-transparent prism that uses transmission and reflection, a grating that uses 0th order light on the outward path and high-order diffracted light on the return path,
It can be configured by a polarization beam splitter or the like which also constitutes an optical isolator in common with the quarter-wave plate.

In FIG. 1, the distance from the semiconductor laser 101 to the round trip path separation element 201 is a, and the round trip path separation element 2 is
If the distance from 01 to the photodetector 111 is b, then a =
When b is through the round trip path separating element 201, the semiconductor laser 101 and the photodetector 111 have a positional relationship of optical conjugate points. Therefore, if the semiconductor laser 101, the photodetector 111, and the reciprocal path separation element 201 are integrated as an integrated optical unit and their positional relationship is reliably positioned and compactly mounted, even if disturbance occurs in the common optical path. , Optical performance will not be disturbed.

The semiconductor laser 101 and the photodetector 11
The positional relationship with 1 can be replaced if the reciprocal path separation element 201 is transmitted on the outward path and reflected on the return path, and if a reflecting member is provided behind the reciprocal path separation element 201 on the return path, both can be replaced. It is also possible to arrange them in the same direction.

FIG. 2 shows the configuration of an example of an optical system of an optical recording medium device when the integrated optical unit according to the present invention is used. This optical system is for a magneto-optical recording medium and is an infinite system. A linearly polarized divergent light beam from the semiconductor laser 101 is incident on a multi-image parallel plane plate 301 having a polarization film 304, and the light beam transmitted through the polarization film 304 and the multi-image parallel plane plate 301 is detected by a photodetector 305 for light amount monitoring. Is received by the collimator lens 3 and the amount of light emitted from the semiconductor laser 101 is controlled based on the output of the collimator lens 3.
A parallel light flux is formed at 10 and is irradiated as a minute spot on the information track 106 of the magneto-optical recording medium 105 by the objective lens 104.

The return light reflected by the magneto-optical recording medium 105 is the objective lens 104 and the collimator lens 3.
By making the light incident on the polarizing film 304 via 10, the return light passing through the polarizing film 304 is spatially separated from the outward light and made incident on the multi-image plane parallel plate 301. The return light that has entered the multi-image parallel plane plate 301 is refracted and transmitted through the multi-image parallel plane plate 301 to impart astigmatism and polarization-separated, and the polarization-separated light flux is used as a signal detection photodetector. Thirty
Light is received at 6, and the MO signal, FES, and TES are detected.

The semiconductor laser 101 is arranged so that the direction of linearly polarized light of its emitted light is incident on the polarizing film 304 as s-polarized light. The multi-image plane parallel plate 301 is configured by bonding a first triangular prism 302 and a second triangular prism 303 each made of a birefringent crystal, for example, lithium niobate, and divergent light flux from the semiconductor laser 101 and magneto-optical property. A polarizing film 304 is formed on the surface of the first triangular prism 302 on which the return light from the recording medium 105 is incident. The polarizing film 3034, for example, has a characteristic that a vibration component (s-polarized light) in a direction orthogonal to the paper surface is reflected by 60 to 90%, and a vibration component in the paper surface (p-polarized light = signal component) is transmitted by almost 100% in terms of signal detection efficiency. And a dielectric multi-layer film.

The optical axis of the first triangular prism 302 is perpendicular to the optical axis of the incident light linearly polarized in the y direction and is perpendicular to the plane of the drawing in order to detect the MO signal by the differential method. The optical axis of the second triangular prism 303 is set such that the return light is divided into two equal oscillation components of the ordinary light and the extraordinary light, which are orthogonal to each other, and the optical axis of the second triangular prism 303 is the optical axis of the first triangular prism 302. On the other hand, in the plane perpendicular to the optical axis, that is, the optical axis is inclined by a predetermined angle.

When the optical axes of the first and second triangular prisms 302 and 303 are set in this way, the linearly polarized light of the incident light (return light) is converted by the first triangular prism 302 into the ordinary light O of substantially equal intensity. And extraordinary light E is polarized and separated, and further by the second triangular prism 303,
Each ray is polarized and separated into ordinary rays OO and EO and extraordinary rays OE and EE to be a total of four luminous fluxes. Here, the light fluxes OO and EE almost overlap, and the light fluxes OE and EO
Are refracted and transmitted in directions opposite to each other, so that substantially three light beams are separated and emitted from the multi-image plane parallel plate 301.

The signal detecting photodetector 306 which receives the return light emitted from the multi-image plane parallel plate 301 has its light-receiving surface at the best image plane position of astigmatism due to the multi-image plane parallel plate 301, that is, multi-image. The parallel plane plate 301 is arranged so as to be located approximately in the middle between the focal plane in the x direction and the focal plane in the y direction. As shown in the plan view of FIG. 3, the detector 306 has a light receiving region 307 that receives the light beam EO from the multi-image plane parallel plate 301 and a light receiving region 308 that receives the light beam OE.
And a four-division light receiving area 30 for receiving the light beams OO and EE
9 and are provided.

According to this optical system, as in the case of FIG. 15, the MO is calculated on the basis of the difference between the outputs of the light receiving regions 307 and 308 which separate and receive the polarization components orthogonal to each other.
The signal can be detected, and the FES can be detected based on the difference in the diagonal sum outputs of the four-divided light receiving regions 309 that receive almost equal amounts of orthogonal polarization components. Further, TES can be detected by the PP method based on the output of the four-division light receiving area 309. The intensity ratio of the light beams (EO), (OE) and (OO + EE) incident on the light receiving regions 307 and 308 and the four-division light receiving region 309 is determined by the angle formed by the optical axes of the first and second triangular prisms 202 and 203. Can be arbitrarily set by appropriately selecting, for example, if this is set to 90 ° and a so-called Wollaston prism is formed, the intensity of (OO + EE) becomes zero.

In constructing the optical system shown in FIG.
In order to realize a compact and thin optical head, the distance from the multi-image plane parallel plate 301 to the signal detection photodetector 306 is
It is desired to suppress the thickness to about 1 to 2 mm.

As a practical design value, when the beam shaping function is not provided, the NA of the collimator lens 310 (objective lens 104 in the finite system) on the semiconductor laser side is 0.15, and the recording medium of the objective lens 104. NA on the side is 0.
It is considered to be about 3.7 times that of 55. In the case of having a beam shaping function, the NA of the collimator lens 310
Becomes smaller, the magnification becomes higher.

In this case, the depth of focus on the surface of the recording medium is ± 1.
Since the recording medium is a reflection system, the movement of the image in the corresponding optical axis direction on the signal detecting photodetector 306 is ± 1 μm × 2 × 3.7 ² ≈ ± 27 μm. Within this range, it is difficult to adjust the signal detection photodetector 306 in the three axis directions. Therefore, conventionally, by using a concave lens to increase the magnification, it is possible to increase the positioning accuracy and adjust the optical axis direction. However, in order to realize a compact and thin optical head, such a concave lens is used. Is not preferable.

If the signal detecting photodetector 306 is to be adjusted in the biaxial directions of the xy plane, the signal detecting photodetector 306 in the optical axis direction with respect to the virtual conjugate position of the light emitting point of the semiconductor laser 101. Positioning accuracy is required.
Moreover, in this case, other errors in the optical axis direction cannot be absorbed by the adjustment, so that the positioning accuracy of the semiconductor laser 101 in the optical axis direction and the multi-image plane parallel plate 30 can be improved.
The thickness error of No. 1, the positioning accuracy of the multi-image plane parallel plate 301, the positioning accuracy of the photodetector 306 for signal detection, and other errors must be suppressed to ± 10 μm or less in consideration of variations in the normal distribution.

In the optical system shown in FIG. 2, the distance from the semiconductor laser 101 to the polarizing film 304 is a, and the polarizing film 30 is
4, the distance from the multi-image parallel plane plate 301 to the signal detection photodetector 306 is b + c, and the refractive index of the multi-image parallel plane plate 301 is n, the semiconductor laser 101 and the multi-image parallel plane plate 301 are interposed. The positional relationship of the optical conjugate point with the signal detection photodetector 306 is a = b (2-1 / n) + c.

Here, as a practical numerical value in consideration of miniaturization and thinning, a = 2.5 mm, multi-image plane parallel plate 30
When the thickness t of 1 is t = 2 mm and n = 2.2, the photodetector 306 for signal detection is output from the exit point of the multi-image plane parallel plate 301.
Distance c is about 1.5 mm, and it becomes difficult to mount it on a normally machined housing with the required accuracy. In addition, when performing 3-axis adjustment within this space, the adjustment man-hour Will be increased.

Embodiments of the integrated optical unit according to the present invention will be described below on the premise of the magneto-optical system shown in FIG. 2. In each embodiment described below, a semiconductor laser and a round-trip path separation are provided. It goes without saying that it can be applied to an optical system for all optical recording media having an element and a photodetector for signal detection.

4 (a) and 4 (b) are a side view and a plan view showing the structure of the mounting substrate used in the first embodiment of the present invention. In the first embodiment, at least the uppermost surface is a mounting substrate 4 made of a (110) silicon wafer.
00, a vertical groove or a vertical wall having {111} as a side surface is formed, and the vertical groove or the vertical wall is positioned in at least the optical axis direction, and the semiconductor laser 101, the multi-image parallel plane plate 301, and the light amount monitor are formed. The photodetector 305 and the photodetector 306 for signal detection are surface-mounted.

The uppermost surface is a (110) silicon wafer,
In forming the vertical groove or the vertical wall having {111} as the side surface, anisotropic etching, which has recently begun to be used in the field of microfabrication, is effective in securing the required accuracy. The anisotropic etching utilizes the fact that when single crystal silicon is used as the material to be processed, its etching rate has a large crystal orientation dependency with respect to an etchant KOH (potassium hydroxide) aqueous solution or the like.

In this case, the etching rate of the crystal plane (111) of silicon is extremely smaller than that of the other crystal planes, and the crystal plane (110) shows the maximum value, and the ratio of the etching rates of both is 1. : It reaches 180. By utilizing this characteristic, if a (110) wafer surface is provided with a mask opening in the <1-12> or <-111> direction for etching, side etching with {111} as a side wall is reduced,
It is possible to obtain a deep groove cut directly below the opening. Moreover, if the ratio of the two etch rates is set to about 1: 180, for example, the width direction error can be suppressed to 3 μm or less by processing the groove depth of 500 μm.

The mounting substrate 400 is made by a photolithography process, and is composed of a (110) silicon wafer 401 and a silicon wafer 402, for example, SiO _2.
It is joined via the etching stopper layer 403 made of. When (110) is the upper surface, as shown in FIG. 5A, the {111} side wall has four surfaces, and the angles formed are 109.5 ° and 70.5 °. Therefore, the (110) silicon wafer 401 on the upper surface has the structure shown in FIG.
As shown in (b), the vertical groove 4 having a side wall of {111}
05, the vertical groove 406, and the vertical groove 407 can be accurately formed by anisotropic etching. The thickness of each wafer is preferably 0.3 to 0.5 mm.

The semiconductor laser 101 is provided in the vertical groove 405.
In consideration of heat dissipation, the stem 404 made of metal, for example,
Positioning and mounting is performed with the positioning adjusted and fixed. In addition, a multi-image parallel plane plate 301 including first and second triangular prisms 302 and 303 is positioned and mounted in the vertical groove 406, and a photodetector 305 for light amount monitor is mounted.
Implement. Further, the signal detecting photodetector 306 is positioned and mounted in the vertical groove 407.

Here, {110
When anisotropic etching with 1} as the side wall is performed, as shown in FIG. 5B, which is a cross-sectional view of FIG. Then, two (111) planes that form an angle of 35.3 degrees with the upper surface appear. These surfaces appear from the corners on both sides of 70.5 degrees, and the area that appears increases as the etching in the depth direction progresses. Proceed to the depth where you stop. Therefore, the 70.5 degree corner shown in FIG. 4 is formed as an extra mask dimension in consideration of the depth of the groove and the flat portion of the bottom surface to be secured.

Also, {111} is added to (110) silicon.
When performing anisotropic etching with a side wall as a side wall, another surface may appear at the convex corner, and the convex corner may be rounded by etching, and dimensional accuracy may not be ensured. In addition, for example, the mask shape is slightly corrected in advance. In this regard, for example, B. Puers, and W. Sansen, "Compensation Structures
for Convex Corner Micromachining in Silicon ", Sen
sors and Actuators, A21-A23, 1990, pp.1036-1941. As another method, a method of etching from both sides of the substrate is also effective.

In this embodiment, the mounting optical elements are mounted by positioning them in the optical axis direction (z) by suppressing at least the thickness accuracy. Therefore, for the semiconductor laser 101 and the signal detection photodetector 306, xy
Adjustment is necessary, but if the dimensional accuracy of each mounting part in the xy direction is secured on the order of μm, xy adjustment is also unnecessary.
Further, if accuracy is ensured only in at least one of the xy directions, for example in the y direction, adjustment in the x direction only is required.

For the xy adjustment of the mounted components, for example, if an infinite optical system is considered, a cat's eye consisting of a corner cube prism, a lens and a mirror placed at its focal position is formed by integrating a collimator lens with an integrated optical unit. It can be adjusted using an optical system such as an optical system that returns collimated light to the light source side as it is.

According to this embodiment, all the parts shown in FIG. 4 are mounted on a quadrangular mounting substrate 400 having a side of about 7 mm.
Can be implemented in. It should be noted that this embodiment is not limited to the optical head used in the magneto-optical recording medium device, but can be effectively applied to at least an optical head mounting a semiconductor laser, a photodetector, and a round-trip path separating element, and is similarly small in size. Can be realized.

FIG. 6 shows a second embodiment of the present invention. In this embodiment, vertical grooves 405 and 406 for mounting the semiconductor laser 101 and the multi-image parallel plane plate 301, respectively, are formed on a sawtooth side wall by anisotropic etching of a (110) silicon wafer. And the mounting method is the same as that of the first embodiment. In FIG. 6, the light quantity monitor photodetector 305 is omitted.

According to this embodiment, there is an advantage that the void portion of the saw-like side wall can be used also as the adhesive reservoir. The sawtooth side wall is formed so as to have an apex angle of 109.5 ° as shown in FIG. 7A or 70% as shown in FIG. 7B depending on the mounting position. .5 °
Is formed so as to have an apex angle of
Can be formed to have apex angles of 109.5 ° and 70.5 °, as shown in FIG.

FIGS. 8A to 8C are views for explaining the third embodiment of the present invention. In this example, (10
0) By utilizing anisotropic etching of a silicon wafer, the mounted components are positioned on the order of μm and surface mounted. Therefore, the upper surface of the mounting substrate 400 made of a (100) silicon wafer is anisotropically etched to form pyramidal grooves 701, 702, 703 and 704.
To form. In this case, each pyramidal groove has four {111} side walls forming an angle of about 54.7 degrees with the lower surface.

A suction hole 705 is provided in each of the pyramidal grooves so that required optical components can be provided through the suction hole 705.
That is, the semiconductor laser 101 fixed to the stem 404 in the pyramidal groove 701 and the multi-image parallel plane plate 30 in the pyramidal groove 702.
1, the signal detection photodetector 306 is mounted in the pyramidal groove 703, and the light amount monitoring photodetector 305 is mounted in the pyramidal groove 704. By mounting in this way, in each pyramid groove, the four sides of the pyramid receive the optical component as a collet, so that accurate positioning mounting balanced with the accuracy of the contact surface becomes possible. The required accuracy of the contact surface in each pyramid groove is that even if the etching time is somewhat excessive, the etching progresses so that the bottom surface dimension is reduced while maintaining the pyramid shape with the mask opening as the top dimension. You can

Here, the stem 404 to which the semiconductor laser 101 is fixed, the photodetector 306 for signal detection and the photodetector 305 for light quantity monitor can be mounted by suctioning through the corresponding suction holes 705 as they are. However, in the case of the multi-image plane parallel plate 301, each side is 4
Since it differs by 5 °, it cannot be sucked and mounted as it is. So, for these parts, for example,
As shown in FIG. 9A, a square intermediate member 706 is positioned and attached to the lower surface of the multi-image plane parallel plate 301, suctioned in that state, and then pyramid-shaped as shown in FIG. 9B. It is mounted in the groove 702. In this case, the intermediate member 706 is
It is possible to use a (100) wafer and cut it into a block shape by etching to form a concavo-convex shape with the pyramidal groove 702.

Alternatively, as shown in FIG. 10A, as the intermediate member 706, as in FIG. 8A,
A (100) silicon wafer having a pyramidal groove 707 and a suction hole 708 formed by anisotropic etching is used, and the pyramidal groove 707 of the intermediate member 706 is used for the suction hole 70.
10B, the multi-image plane parallel plate 301 is suction-positioned and fixed, and then the intermediate member 706 is mounted on the mounting substrate 40 as shown in FIG. 10C.
The pyramidal groove 702 formed in 0 is mounted by suction.

As described above, if each optical component is sucked and mounted as a collet, an accuracy of about ± 5 μm can be obtained.

When each optical component is mounted as a collet by suction as in the third embodiment, as shown in FIG.
A substrate similar to the (100) silicon wafer shown in (1) can be used as a collet jig for positioning and mounting optical components on the mounting substrate 400. FIG. 11 (a)
Shows the structure of the collet substrate 800 in this case, which has exactly the same structure as the mounting substrate 400 shown in FIG. 8A and has pyramidal grooves 801 to 804. The difference is that it is not used as a mounting substrate, but as a collet jig for positioning and carrying optical components.

As shown in FIG. 11B, this collet substrate 800 is attached to a precision moving arm 807, and a required optical component 808 which is placed on a component table 805 and conveyed is transferred by suction, and The transferred optical component 808 is moved by the precision moving arm 807, and the optical component 808 shown in FIG.
As shown in FIG. 1 (c), it is transferred onto the mounting substrate 400 that is successively conveyed onto the substrate table 806, and is bonded and mounted by the dispenser 809. The precision moving arm 807 includes a parts table 8
05 and the substrate table 806 are accurately positioned and reciprocated.

By mounting the required optical components 808 in this manner, each optical component 808 can be positioned on the order of μm and surface-mounted. In this mounting method, the mounting substrate 400 may be a simple flat plate. Further, a plurality or all of the optical components 808 to be mounted are sucked simultaneously and transferred to the collet substrate 800,
The mounting substrate 400 with the height direction aligned with the same plane
May be simultaneously transferred and mounted, or may be transferred one by one and transferred and mounted.

12 (a) to 12 (f) show a fourth embodiment of the present invention.
It is a figure for explaining an example. This embodiment is shown in FIG.
On a base substrate 901 shown in FIG. 2A, a spacer substrate 902 made of a (100) wafer shown in FIG. 12B and a positioning substrate 903 made of a (110) wafer shown in FIG. 12C are sequentially laminated. Then, the mounting substrate 400 is configured. It should be noted that the spacer substrate 902 and the positioning substrate 903 are respectively formed into a predetermined pattern by etching, and then are formed as shown in FIGS.
As shown in FIG. Further, the base substrate 901, the spacer substrate 902, and the positioning substrate 9
As for 03, the thickness is about 0.5 mm, 0.3-
A silicon wafer of about 0.5 mm and about 0.1 to 0.2 mm is used.

According to this embodiment, a deep groove having a small inclined (111) plane and a large depth can be formed as compared with the case where a deep groove is formed on one (110) wafer by anisotropic etching. Therefore, the optical component can be more accurately positioned and mounted. A (100) wafer may be used as the positioning substrate 903. In this case, as shown in FIG. 12F, since the pyramid wall opening can be formed, its slope can be used as a guide when inserting the optical component, which facilitates positioning and mounting. be able to.

FIGS. 13A to 13C show the fifth embodiment of the present invention.
It is a figure for explaining an example. In this embodiment, a spacer substrate 902 is bonded to a base substrate 901, and a polyimide film 905 is further coated thereon to a thickness of about 100 μm to form a mounting substrate 400 as follows. That is, a desired mask opening is formed in the uppermost polyimide film 905, and RIE (Reactive Ion Etc) is performed.
h) to form a positioning pattern (see FIG. 13).
(A)) After that, using this polyimide film 905 as a mask, the spacer substrate 902 is subjected to isotropic etching (for example, HF + HNO ₃ or the like is used as an etchant) until it reaches the surface of the base substrate 901 (FIG. 13).
(B)), the mounting substrate 400 is created. The surface of the base substrate 901 is thinly coated with a substance that serves as a stopper for isotropic etching, such as a polyimide film or a nitride film, or the material itself that serves as a stopper is used.

According to this embodiment, as in the fourth embodiment, the oblique (111) plane is smaller than that in the case where the deep groove is formed in one (110) wafer by anisotropic etching, and Since the deep groove having a large depth can be formed, the optical component can be more accurately positioned and mounted. In addition, "polyimide + RIE" has no directionality, and side etching is several μm up to a thickness of 100 μm.
And the spacer substrate 902 is
Since it is isotropically etched, a positioning pattern in an arbitrary direction can be formed. Therefore, even if the pattern has an arbitrary shape, it is possible to perform positioning mounting on the order of μm, and there is an advantage that the applicability is high. In addition,
Instead of "Polyimide + EIE", "Thick resist + U
It is also possible to use “V exposure” or “photosensitive polyimide + UV exposure”.

The present invention is not limited to the above-mentioned embodiments, but various modifications and changes can be made. For example, in the above-described embodiment, the concave groove is formed on the mounting substrate, and the optical component is inserted into the groove for positioning and mounting. It can also be configured to position-mount components.

Further, the stem 404 for heat dissipation of the semiconductor laser 101 is not limited to a metal, and a silicon block formed into a fin shape by anisotropic etching may be used. Furthermore, the semiconductor laser 101 can be directly positioned and mounted on the mounting substrate 400 without using the stem 404.

Furthermore, the present invention is not limited to the above-described magneto-optical optical system, but is effectively applied to all optical systems for optical recording media having a semiconductor laser, a round-trip path separating element, and a photodetector for signal detection. can do.

To summarize the effects of the embodiments described above,
It is as follows. Since parts that require precision and environmental resistance can be mounted compactly and accurately, high stability, low cost, and small size and weight can be achieved. Since the positional relationship of the semiconductor laser, the round-trip path separating element, and the photodetector for signal detection in the optical axis direction is secured on the order of μm,
Adjustment can be greatly simplified compared to the conventional method. Further, in the case of an infinite system, adjustment can be performed using a simple pseudo optical system. That is, since the adjustments in the xy direction and the z direction do not interfere with each other, the adjustment with the intermediate characteristic value becomes possible. Since the adjustment points are only the photodetector for signal detection or the semiconductor laser, the number of adjustment steps can be significantly simplified. By further increasing the accuracy, it is possible to implement without any adjustment. It is possible to package the semiconductor laser, the round-trip path separation element, and the photodetector for signal detection into one package.

[0062]

According to the present invention, at least a vertical groove or wall having {111} as a side surface formed on a mounting substrate made of a silicon wafer having a (110) top surface,
Alternatively, at least the uppermost surface is formed on a mounting substrate made of a (100) silicon wafer, in a pyramidal groove having a side surface of {111}, or formed on the surface of a mounting substrate having a polyimide film on the uppermost surface. Since the semiconductor laser, the photodetector for signal detection, and the round-trip path separation element are surface-mounted in the vertical groove at least in the optical axis direction, the position adjustment of each optical component can be facilitated, and the size and thickness are small. Therefore, it is possible to obtain an integrated optical unit that is inexpensive and has excellent environment resistance.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of an optical system of an optical recording medium device when an integrated optical unit according to the present invention is used.

FIG. 2 is a diagram showing a configuration of an example of an optical system of an optical recording medium device when the integrated optical unit according to the present invention is used.

FIG. 3 is a diagram showing a configuration of a photodetector for signal detection shown in FIG.

FIG. 4 is a diagram for explaining the first embodiment of the present invention.

FIG. 5 is also a diagram for explaining the first embodiment.

FIG. 6 is a diagram for explaining the second embodiment of the present invention.

FIG. 7 is likewise a diagram for explaining the second embodiment.

FIG. 8 is a diagram for explaining the third embodiment of the present invention.

FIG. 9 is also a diagram for explaining the third embodiment.

FIG. 10 is likewise a diagram for explaining the third embodiment.

FIG. 11 is a diagram for explaining an example of a mounting method according to the third embodiment.

FIG. 12 is a drawing for explaining the fourth embodiment of the present invention.

FIG. 13 is also a diagram for explaining the fifth embodiment.

FIG. 14 is a diagram showing a conventional optical head.

15 is a diagram showing the configuration of the signal detection photodetector shown in FIG.

[Explanation of symbols]

 Reference Signs List 101 semiconductor laser 103 polarizing film 104 objective lens 105 magneto-optical recording medium 106 information track 111 photodetector 201 reciprocating path separation element 301 multi-image parallel plane plate 305 light intensity monitor photodetector 310 collimator lens 306 signal detection photodetector 400 Mounting substrate 401 (110) Silicon wafer 402 Silicon wafer 403 Etching stopper layer 404 Stem 405, 406, 407 Vertical groove

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[Procedure amendment]

[Submission date] December 20, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

In order to achieve the above object, the first invention is an integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium. A mounting substrate formed of a (110) silicon wafer having an uppermost surface and having a vertical groove or a vertical wall having {111} as a side surface, and at least the optical axis direction in the vertical groove or the vertical wall of the mounting substrate. Positioned and mounted, a semiconductor laser that emits a light beam, a photodetector that receives the return light from the optical recording medium, and a light beam from the semiconductor laser is guided to the optical recording medium side, and from the optical recording medium. And a reciprocating path separation element for guiding return light to the photodetector side.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

A second invention is an integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium, wherein at least the uppermost surface is (100).
And a mounting substrate formed of a silicon wafer having a pyramidal groove having {111} as a side surface, and mounted in the pyramid groove of the mounting substrate at least in the optical axis direction,
A semiconductor laser that emits a light flux, a photodetector that receives return light from the optical recording medium, a light flux from the semiconductor laser is guided to the optical recording medium side, and return light from the optical recording medium is detected by the light. It is characterized by having a reciprocating path separation element for guiding to the container side.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

Further, a third invention is an integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium, which comprises a polyimide film having substantially vertical grooves formed on its uppermost surface. A mounting substrate having, a semiconductor laser that emits a light beam, is mounted in the vertical groove of the mounting substrate while being positioned at least in the optical axis direction, a photodetector that receives return light from the optical recording medium, and It is characterized in that it has a reciprocal path separating element for guiding the light beam from the semiconductor laser to the optical recording medium side and guiding the return light from the optical recording medium to the photodetector side.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

The semiconductor laser 101 is arranged so that the direction of linearly polarized light of its emitted light is incident on the polarizing film 304 as s-polarized light. The multi-image plane parallel plate 301 is configured by bonding a first triangular prism 302 and a second triangular prism 303 each made of a birefringent crystal, for example, lithium niobate, and divergent light flux from the semiconductor laser 101 and magneto-optical property. A polarizing film 304 is formed on the surface of the first triangular prism 302 on which the return light from the recording medium 105 is incident. The polarizing film 304 reflects, for example, a vibration component (s-polarized light) in a direction orthogonal to the paper surface by 60 to 90%, and a vibration component (p-polarized light = signal component) in the paper surface is transmitted by almost 100% in terms of signal detection efficiency. A dielectric multi-layer film is used so as to have characteristics.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

In this case, the etching rate of the crystal plane (111) of silicon is extremely smaller than that of the other crystal planes, and the crystal plane (110) shows the maximum value, and the ratio of the etching rates of both is 1. : It reaches 180. Utilizing this characteristic, if a mask opening is provided in the <1-12> or <-112> direction on the (110) wafer surface and etching is performed, side etching with {111} as a side wall is reduced,
It is possible to obtain a deep groove cut directly below the opening. Moreover, if the ratio of the two etch rates is set to about 1: 180, for example, the width direction error can be suppressed to 3 μm or less by processing the groove depth of 500 μm.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction content]

[0062]

According to the present invention, at least a vertical groove or a vertical wall having {111} as a side surface is formed on a mounting substrate made of a silicon wafer having a (110) top surface,
Alternatively, at least the uppermost surface is formed on a mounting substrate made of a (100) silicon wafer, in a pyramidal groove having a side surface of {111}, or formed on the surface of a mounting substrate having a polyimide film on the uppermost surface. Since the semiconductor laser, the photodetector for signal detection, and the round-trip path separating element are mounted in the vertical groove at least in the direction of the optical axis, the position adjustment of each optical component can be facilitated, and the size and thickness can be reduced. In addition, it is possible to obtain an integrated optical unit that can be manufactured at low cost and has excellent environment resistance.

Claims (3)

[Claims] 1. An integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium, wherein at least an uppermost surface is made of a (110) silicon wafer, and {111} is a side surface. And a mounting substrate having a vertical groove or a vertical wall formed thereon, and a semiconductor laser that emits a light beam and is surface-mounted on the vertical groove or vertical wall of the mounting substrate at least in the direction of the optical axis, and the optical recording medium. A photodetector that receives the return light from the semiconductor laser, and a round-trip separation element that guides the light flux from the semiconductor laser to the optical recording medium side and guides the return light from the optical recording medium to the photodetector side. An integrated optical unit having. 2. An integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium, wherein at least an uppermost surface is made of a (100) silicon wafer, and {111} is a side surface. A mounting substrate having a pyramidal groove formed therein, and a semiconductor laser emitting a light beam and receiving return light from the optical recording medium, which is surface-mounted in the pyramidal groove of the mounting substrate at least in the optical axis direction. And a round-trip path separating element that guides the light beam from the semiconductor laser to the optical recording medium side and guides the return light from the optical recording medium to the photodetector side. Integrated optical unit. 3. An integrated optical unit used in an optical recording medium device for recording / reproducing information on / from an optical recording medium, the mounting substrate having a polyimide film having substantially vertical grooves formed on an uppermost surface thereof. In the vertical groove of the mounting substrate, a semiconductor laser which is surface-mounted at least in the direction of the optical axis, emits a light beam, a photodetector that receives return light from the optical recording medium, and a light beam from the semiconductor laser. To the optical recording medium side, and a return path separating element for guiding the return light from the optical recording medium to the photodetector side, an integrated optical unit.