JP2002116361A - Method and device for manufacturing laser diode unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome the problem of a prior art such that errors caused by the increase of tact or attachment are easily generated because a measuring device has to be replaced every adjusting process in the assembling of an optical pickup. SOLUTION: This device is composed of a collimator lens 7 which forms emitting light from a semiconductor laser 1 into parallel beams, a plurality of half mirrors 8, 10 and 11 which branch light from the collimator lens 7, a light quantity distribution measuring camera 18 which measures the distribution of light quantity, an image pickup camera 15 which is arranged at a focal position of an image forming lens 14, and a lighting source 13 which lights a light receiving part 2. The collimator lens 7 is adjusted so as to be focused on the light receiving part 2, the semiconductor laser 1 is adjusted by shifting so that the center of gravity is positioned at the center of the light quantity distribution measuring camera 18, and the position of the light receiving part is adjusted so that the center of the light receiving part 2 becomes the center of the image pickup camera 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information storage medium of an optical disk system, for example, a DVD (Digital Vers).
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a laser diode unit including a semiconductor laser and a light receiving unit in an optical pickup for reading / writing information from / to an optical disk.

[0002]

2. Description of the Related Art Conventionally, in assembling an optical pickup, a semiconductor laser, a mirror, a lens, and a light receiving unit are incorporated in one optical base, and an optical axis measurement and a light amount distribution measurement are performed to adjust a laser, a mirror, and a lens. And adjusting the light receiving section while reproducing the signal.

[0003]

However, in the above-mentioned method, the measuring device and the adjusting device must be switched for each adjusting step, and the tact time is increased, and the mounting of the base to the measuring device and the adjusting device is required. Errors were easy to occur.

SUMMARY OF THE INVENTION It is an object of the present invention to shorten the tact time for assembling and adjusting an optical pickup and improve the accuracy of the adjustment by optically adjusting the semiconductor laser and the light receiving unit as one unit in advance.

[0005]

According to the present invention, an image of a light receiving section is captured by an imaging camera via a collimator lens and an imaging lens, and the position of the collimator lens is adjusted so as to be in focus. And adjusting the position of the light receiving unit so that the image of the light receiving unit is at a predetermined position of the imaging camera. The light emitted from the semiconductor laser is transmitted through the collimator lens and the imaging lens to the imaging camera. In the above, at the predetermined position, and adjust the position of the semiconductor laser so that the focus is adjusted, the emitted light of the semiconductor laser is collimated through the collimator lens, the light amount centroid is measured, The attitude of the semiconductor laser is adjusted so that the center of gravity of the light quantity is at a predetermined position.

Thus, the adjustment of the laser diode unit can be performed promptly, and the tact time for adjusting the optical pickup can be shortened and the adjustment accuracy can be improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for manufacturing a laser diode unit according to a first embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes a semiconductor laser, reference numeral 2 denotes a light receiving unit, and reference numeral 3 denotes a polarization beam splitter, which transmits the light emitted from the semiconductor laser 1, reflects the return light from the disk, and enters the light receiving unit 2. It is for making light. Reference numeral 6 denotes a base on which the polarization beam splitter 3 is arranged, and the semiconductor laser 1 whose position and orientation are adjusted and the light-receiving unit 2 whose position is adjusted are fixed with an adhesive or the like. As described above, the laser diode unit includes the semiconductor laser 1, the light receiving unit 2,
It comprises a polarizing beam splitter 3 and a base 6. The chuck 4 holds the semiconductor laser 1 and holds the semiconductor laser 1.
For adjusting the position and orientation of the camera, the movement in the XYZ directions, the tilt θx about the x-axis, and the tilt θ about the y-axis.
y is possible, and the center of the tilt is the light emitting point of the semiconductor laser 1. The chuck 5 holds the light receiving unit 2 and adjusts the position of the light receiving unit 2, and can move in the YZ directions. Here, the distance in the X direction between the light receiving unit 2 and the polarization beam splitter is predetermined at a predetermined position, and therefore does not need to be adjusted. The collimator lens 7 is movable in the Z direction and converts the light emitted from the semiconductor laser 1 into parallel light. The half mirrors 8, 10, and 11 split the incident light into transmitted light and reflected light. The signal reproducing optical system 9 using an optical pickup is different from an ordinary optical pickup,
It consists of an optical disc without a light source and a collimator lens, and an optical disc without a groove. The imaging lens 14
The reflected light from the half mirror 11 is imaged on a camera 15 disposed at the focal position. The fiber illumination 13 illuminates the light receiving unit 2 via the condenser lens 12, and the fiber illumination 13 is arranged such that the fiber light exit surface forms an image on the collimator lens 7 by the lens 12. The camera 18 measures the center of gravity of the light quantity of the semiconductor laser 1.

The operation of the laser diode unit manufacturing apparatus configured as described above will be described with reference to FIGS.

First, as shown in FIG. 2, the light receiving unit 2 is held by the chuck 5 and the fiber illuminating unit 13 illuminates the light receiving unit 2. The adjustment is performed by moving the collimator 7 in the Z direction so that the camera 15 is focused on the pattern of the light receiving unit 2. The center of the pattern of the light receiving unit 2 is the camera 1
5, the light receiving unit 2 is positioned in the Y, Z
Direction to make adjustments.

Next, as shown in FIG.
Is held by the chuck 4 and the semiconductor laser 1 is turned on.
The position of the light emitting point of the semiconductor laser 1 becomes the center of the camera 15, and the position of the light emitting point is minimized by moving the semiconductor laser 1 in the X, Y, and Z directions with the chuck 4 so as to minimize the spot size of the light emitting point. The center of the light amount is measured, and the attitude of the semiconductor laser 1 is changed by the chuck 4 so that the tilt θx and θy are adjusted so that the center of the light amount is at the center of the camera.

Finally, a sine wave signal is input to the optical pickup 9, and the objective lens of the optical pickup is vibrated in the focus direction. At this time, the return light from the optical pickup 9 is received by the light receiving unit 2, and fine adjustment in the Y and Z directions of the light receiving unit 2 is performed so that the S-shaped signal amplitude of the focus becomes maximum.

After the adjustment, the semiconductor laser 1 and the light receiving section 2 are bonded and fixed to the base 6.

FIG. 4 shows the above flow.

As described above, according to the first embodiment of the present invention, the position adjustment and the posture adjustment of the semiconductor laser and the position adjustment of the light receiving section can be performed at one time, so that the chuck can be gripped and the adjuster can be switched. It is possible to prevent an increase in tact, a variation, and a decrease in accuracy.

In addition, by adjusting the semiconductor laser and the light receiving unit in advance to form a unit, the number of adjustment axes in the assembly adjustment of the optical pickup can be reduced, and the adjustment tact can be reduced.

The half mirrors 8 and 10 may be of a cube type or a plate type.
D illumination may be used. Further, the collimator lens 7 may be a group lens such as a single lens or a microscope objective lens.

Next, an apparatus for manufacturing a laser diode unit according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 5, those having the same numbers as those in FIG. 1 are the same as those in the first embodiment.

The lens 17 forms an image on the camera 18 of the emitted light of the semiconductor laser 1 that has been made parallel by the collimator lens 7. The focal length of the collimator lens 7 is f1, the lens 1
7, the distance from the camera-side focal position of the collimator lens 7 to the lens 17 is c, and the focal length of the lens 17 is
Assuming that the distance from to the camera 18 is d, the lens 17 is arranged so that the relationship of (Equation 1) holds.

[0020]

(Equation 1)

Next, the effect of the lens 17 will be described with reference to FIGS.

FIG. 6 shows a light amount distribution measuring optical system according to the first embodiment. The light emitted from the semiconductor laser 1 is collimated by a collimator lens 7, and the light amount distribution at that time is measured by a camera 18. I have. Considering the case where the focal length of the collimator lens 7 is f1, the distance from the collimator lens 7 to the camera 18 is L, and the semiconductor laser 1 is deviated by a from the optical axis of the optical system for measuring the light amount distribution, b =
The light amount distribution is shifted by a × L / f1, resulting in a measurement error. When the distance L between the collimator lens 7 and the camera 18 can be made sufficiently small, the measurement error is small, but for example, f1 = 10 mm, L = 200 mm, a = 10 μ
Assuming that m, the camera 18 has a shift of b = 200 μm, and the tilt of the semiconductor laser is 20 mrad (about 1 °).
It has shifted. For this reason, in the first embodiment, when adjusting the tilt of the semiconductor laser, the position of the light emitting point of the semiconductor laser must be always brought to the center of the optical system.

On the other hand, in the second embodiment shown in FIG. 5, the image of the focal plane on the camera 18 side of the collimator lens 7 is reflected on the camera 18 by inserting the condenser lens 17. here,
At the focal position of the collimator lens 7 on the camera 18 side, there is a characteristic that the light amount distribution does not change even if the position of the light emitting point of the semiconductor laser moves, so that the shift of the light amount distribution at the camera 18 becomes zero.

As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained. Further, in the tilt adjustment of the semiconductor laser, there is no measurement error due to the displacement of the light emitting point, and the accuracy is high. Can be adjusted. Further, since there is no measurement error in the tilt adjustment of the semiconductor laser, the semiconductor laser 1
The number of repetitions of the tilt adjustment and the position adjustment of the light emitting point can be reduced, and the adjustment time can be shortened.

In FIG. 7, one lens is used.
As shown in FIG. 8, two lenses such as lenses 19 and 20 are used, the focal position of the collimator lens 7 and the focal position of the lens 19 are overlapped, and the focal position of the lens 19 and the focal position of the lens 20 are overlapped. In addition, an image of the focal position of the collimator 7 on the camera 18 side may be formed on the camera 18.

Next, a third embodiment of the laser diode unit adjusting apparatus of the present invention will be described with reference to FIG. In FIG. 9, the components having the same numbers as those in FIG. 5 are the same as those in the second embodiment.

The wedge-shaped transparent substrate 21 is arranged such that the normal to the surface is approximately 22.5 ° with respect to the light reflected by the half mirror 16. In the wedge-shaped substrate 21, reflection occurs on the front surface and the rear surface, and light interference occurs. Mirror 31
Is arranged at an angle of approximately 22.5 ° with respect to the light reflected by the wedge-shaped substrate 21. Therefore, the light emitted from the mirror 22 is perpendicular to the light incident on the wedge-shaped substrate 21. The camera 32 receives the light reflected by the mirror 31.

FIG. 10 is a view of the wedge-shaped substrate 21 viewed from the same direction as FIG. 9, and FIG. 11 is a view of the wedge-shaped substrate 21 viewed from the direction of arrow 30 in FIG. The wedge-shaped substrate 21 has a wedge shape when viewed from the direction of the arrow 30 in FIG. In FIG.
Are perpendicularly incident on the wedge-shaped substrate 21. On the other hand, the cross section in the direction parallel to the paper of FIG.
Enter the substrate 21 at an angle of 22.5 °.

When the light beam 23 is incident on the wedge-shaped substrate 21, a part thereof is reflected on the surface and becomes a light beam 24. The remaining light ray 25 travels inside the substrate 21, and a part of the light ray 25 is reflected again on the back surface, and becomes a light ray 26. In FIG. 11, the wedge-shaped substrate 21
Is wedge-shaped, so that the surface reflected light 24
On the other hand, the direction of the back surface reflected light 26 is slightly different. For this reason, when the light beam 24 and the light beam 26 overlap, an interference fringe which is a fringe of a periodic intensity distribution is generated.

In FIG. 10, the shape of the wedge-shaped substrate 21 is rectangular, and
Since the light enters from an oblique direction of 2.5 °, the surface reflected light 24
And the back surface reflected light 26 are parallel to each other, but slightly deviate from each other. At this time, if the incident light beam 23 is parallel light,
Even if the light beam 24 and the light beam 26 overlap, no stripes occur. However, when the incident light beam 23 is divergent light or convergent light, a periodic intensity distribution occurs due to the overlap of the light beam 24 and the light beam 26.

When the light intensity distribution in the direction perpendicular to the plane of FIG. 9 and the light intensity distribution in the direction horizontal to the plane of FIG.
2 (b), the stripes are inclined as shown in FIG. 12 (a) when the light beam 24 is divergent light, and the stripes are inclined in the opposite direction (FIG. 12 (c)) when the light beam 24 is convergent light. Lean like so.
When the difference between the light emitting point position of the semiconductor laser 1 and the focal position of the collimator lens 7 is small, that is, when the light incident on the wedge-shaped substrate 21 is close to parallel light, the light emitting point position of the semiconductor laser 1 and the collimator lens 7 Is substantially proportional to the inclination of the interference fringes on the wedge-shaped substrate 21. Therefore, the position of the semiconductor laser 1 can be obtained from the inclination of the interference fringes.

If the angle of incidence of the light ray 23 on the substrate 21 increases when the diameter of the light ray 23 is small, the amount of lateral shift of the light ray 26 with respect to the light ray 24 in FIG. 10 increases, the interference area decreases, and the direction of the stripes decreases. Observation with the camera 32 becomes impossible. For example, in the case of an optical disc or the like, the beam diameter is 5 m by a combination of the semiconductor laser 1 and the collimator lens 7.
m. Assuming that the angle of incidence of the light beam 23 on the wedge-shaped substrate 21 is 45 ° and the thickness of the substrate 21 is 3 mm, the amount of lateral displacement becomes 2.3 mm, and only about 1/3 of the beam interferes.

If the thickness of the wedge-shaped substrate 21 is reduced, the amount of lateral displacement can be reduced. However, the strength of the wedge-shaped substrate 21 is weakened, the deflection is liable to occur, and the parallelism of light cannot be measured accurately. Thus, by reducing the angle of incidence of the light beam on the wedge-shaped substrate 21, the interference area can be increased without making the wedge-shaped substrate 21 thinner. By setting the angle of incidence on the wedge-shaped substrate 21 to 22.5 °, the amount of lateral displacement can be reduced to 1.1 mm. Further, by changing the direction of the light beam by 45 ° by the mirror 31 and setting the direction of the emitted light of the mirror 31 to 90 ° with respect to the light incident on the wedge-shaped substrate 21, the optical system can be downsized. .

Next, differences between the first and second embodiments and the third embodiment will be described. In the first and second embodiments, the position of the semiconductor laser 1 in the Z direction is measured by the camera 1.
It was necessary to find a position where the spot diameter shown in FIG. Since the position of the semiconductor laser 1 in the Z direction is not directly known from the spot diameter, it is necessary to search in a wide range and further drive in while fine-adjusting the Z position of the semiconductor laser 1 so as to minimize the spot diameter. .

On the other hand, in the third embodiment, since the Z position of the semiconductor laser 1 can be determined from the inclination of the interference fringes on the wedge-shaped substrate 21, the Z adjustment of the semiconductor laser 1 can be performed at one time. Time can be shortened.

As described above, according to the third embodiment, the same effects as those of the first and second embodiments can be obtained. Further, from the inclination of the interference fringe on the wedge-shaped substrate 21, the Z position of the semiconductor laser 1 can be obtained. Therefore, the Z adjustment of the semiconductor laser 1 can be performed at once, and the adjustment time can be shortened.

[0037]

According to the first embodiment of the present invention, the adjustment of the position of the semiconductor laser, the adjustment of the tilt and the adjustment of the position of the light receiving portion can be performed at one time. , Variation, and decrease in accuracy can be prevented. In addition, by adjusting the semiconductor laser and the light receiving unit in advance and unitizing them, the number of adjustment axes in the assembly adjustment of the optical pickup can be reduced, and the adjustment tact can be reduced.

According to the second embodiment, the same effects as those of the first embodiment can be obtained. In addition, in the tilt adjustment of the semiconductor laser, there is no measurement error due to the displacement of the light emitting point, and a highly accurate adjustment can be performed. it can. Furthermore, since there is no measurement error in the tilt adjustment of the semiconductor laser, the number of repetitions of the tilt adjustment of the semiconductor laser and the position adjustment of the light emitting point can be reduced, and the adjustment time can be shortened.

According to the third embodiment of the present invention,
The same effects as those of the first and second embodiments can be obtained.
From the inclination of the interference fringes on the wedge-shaped substrate,
Since the position is known, the Z adjustment of the semiconductor laser can be performed at once, and the adjustment time can be shortened.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a laser diode unit manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an adjustment method of the laser diode unit manufacturing apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining an adjustment method of the laser diode unit manufacturing apparatus according to the first embodiment of the present invention.

FIG. 4 is a flowchart of a method for manufacturing a laser diode unit according to the first embodiment of the present invention.

FIG. 5 is a schematic view of a laser diode unit manufacturing apparatus according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a light amount distribution measuring optical system according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of a light amount distribution measuring optical system according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a light amount distribution measuring optical system according to a second embodiment of the present invention.

FIG. 9 is a schematic view of a laser diode unit manufacturing apparatus according to a third embodiment of the present invention.

FIG. 10 is a diagram illustrating light reflection on a wedge-shaped substrate.

FIG. 11 is a view for explaining light ray reflection on a wedge-shaped substrate.

FIG. 12 is a view showing interference fringes formed by a wedge-shaped substrate in the laser diode unit manufacturing apparatus according to the third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Light-receiving part 3 Polarization beam splitter 7 Collimator lens 8 Half mirror 13 Illumination device 14 Imaging lens 15 CCD camera

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 7/22 G11B 7/22 H01S 5/022 H01S 5/022 F-term (Reference) 2F065 AA03 AA17 BB03 CC03 DD03 FF42 FF44 FF51 GG04 HH04 JJ03 JJ26 LL00 LL02 LL12 LL37 MM02 QQ28 QQ32 2H043 AD02 AD11 AD12 AD20 5D119 AA38 BA01 BB01 BB04 FA05 FA37 LB07 NA04 NA06 5F073 AB21 AB25 AB27 BA05 FA30

Claims (7)

[Claims] 1. A method of manufacturing a laser diode unit by adjusting a position and a posture of a semiconductor laser and a light receiving unit of a laser diode unit, wherein an image of the light receiving unit is captured via a collimator lens and an imaging lens. A step of adjusting the position of the collimator lens so that the focal point matches; a step of adjusting the position of the light receiving unit so that the image of the light receiving unit is at a predetermined position of the imaging camera; and Imaging the emitted light of the laser by the imaging camera via the collimator lens and the imaging lens, and adjusting the position of the semiconductor laser so as to be in focus at the predetermined position; and The emitted light is collimated through the collimator lens, the center of gravity of the light amount is measured, and the attitude of the semiconductor laser is adjusted so that the center of gravity of the light amount is at a predetermined position. And a step of adjusting the laser diode unit. 2. The step of adjusting the attitude of the semiconductor laser,
The emitted light of the semiconductor laser is collimated through the collimator lens, the collimated light is condensed by a condenser lens, and the light quantity centroid is measured, and the light quantity centroid becomes a predetermined position. 2. The method for manufacturing a laser diode unit according to claim 1, wherein the adjustment is performed as described above. 3. The step of adjusting the position of the semiconductor laser,
The emitted light of the semiconductor laser is collimated through the collimator lens, and the position of the semiconductor laser in the optical axis direction is adjusted by optical interference of reflected light on the front side and the back side of the wedge-shaped substrate. The method for manufacturing a laser diode unit according to claim 1. 4. An apparatus for manufacturing a laser diode unit by adjusting a position and a posture of a semiconductor laser and a light receiving section of a laser diode unit, wherein an image of the light receiving section and emission light of the semiconductor laser are connected to a collimator lens. An imaging camera that captures an image via an image lens, a light amount centroid measuring unit that converts the emitted light of the semiconductor laser into a parallel light through the collimator lens, and measures a light amount centroid, and a collimator lens that adjusts the position of the collimator lens A position adjusting unit, a semiconductor laser position / posture adjusting unit for adjusting the position / posture of the semiconductor laser, and a light receiving element position adjusting unit for adjusting the position of the light receiving element; manufacturing device. 5. A collimator lens position adjustment unit includes a collimator lens position control unit that performs position adjustment based on the light receiving element data imaged by the imaging camera, and the light receiving element position adjustment unit includes a light receiving element position adjustment unit. A light-receiving element position control unit that performs position adjustment based on the imaged light-receiving element data, wherein the semiconductor laser position / posture adjustment unit outputs the emission light of the semiconductor laser through the collimator lens and the imaging lens. 5. The apparatus according to claim 4, further comprising a semiconductor laser position / posture control unit that performs position adjustment based on data captured by the imaging camera, and performs attitude adjustment based on the data measured by the light quantity centroid measurement unit. Equipment for manufacturing laser diode units. 6. The light quantity centroid measuring means has a condensing lens for condensing the light collimated by the collimator lens to the light quantity centroid measuring means.
An apparatus for manufacturing a laser diode unit according to any one of the above. 7. A wedge-shaped substrate that reflects light emitted from the semiconductor laser and made collimated by the collimator lens, and a wedge-shaped substrate having a front surface and a back surface. 6. An optical interference measuring means for measuring interference of reflected light, wherein the position of the semiconductor laser in the optical axis direction is adjusted based on data measured by the optical interference measuring means. 7. The apparatus for manufacturing a laser diode unit according to any one of claims 1 to 6.