JPH0933236A - Measuring method for optical axis of optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a measuring method whose reproducibility is excellent even when a deviation exists between the outer circumferential face of a package and the optical axis of an optical module and in which a measurement can be performed with high accuracy by correcting the reference face of the package so as to be perpendicular to the reference optical axis of an optical measuring system and then measuring a displacement angle which is formed by the reference optical axis and by the optical axis of the package. SOLUTION: A control part 30 measures dislocation between the center of a package 2 and a light-emitting point. It outputs a driving signal to operating shafts 13a, 14a on the basis of the image signal of the light-emitting point which has been photographed by an infrared camera 23. It drives an X-axis linear stage 13 and a Y-axis linear stage 14 so as to make the light-emitting point agree with a reference optical axis As. Then, distances up to the reference face 2a of a package 2 are measured in a plurality of points, and an X-axis swivel stage 11 and a Y-axis swivel stage 12 are turned so that the distances becomes equal. Then, the reference face 2a of the package 2 is corrected so as to be perpendicular to the reference optical axis As, a raising and lowering stage 21 is then raised and lowering in Z-axis direction, and a displacement angle which is formed by the reference optical axis As and by the optical axis of the package is measured.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for measuring an optical axis of an optical module.

[0002]

2. Description of the Related Art When an optical module is assembled by assembling a condenser lens, an optical fiber or the like into a package containing optical components such as a condenser lens and a light emitting element, an automatic assembling apparatus is used. In this automatic assembly device, the outer peripheral surface of the package, for example, the outer surface or the bottom surface is fixed as a reference surface to the jig of the optical axis measuring device, and the optical axis of the optical module is measured with respect to a predetermined axis of the jig. Was there.

[0003]

By the way, in the case of measuring the optical axis of the optical module as described above, unless the outer side surface or the bottom surface of the package is parallel or perpendicular to the optical axis of the optical module, There is a problem that the position reproducibility is deteriorated because the fixing position to the jig is different. In addition, if the outer surface or bottom surface of the package is used as a reference surface when measuring the optical axis when fixing to a jig, the measurement accuracy cannot be improved, and when the optical components are assembled to the package, the optical There was a problem that the optical axis of the module had to be measured again.

The present invention has been made in view of the above points, and in measuring the optical axis of the optical module, the positional reproducibility of the package is improved even if the outer peripheral surface of the package is deviated from the optical axis of the optical module. An object of the present invention is to provide an optical axis measuring method of an optical module which is excellent and can measure the optical axis of the optical module with high accuracy regardless of the outer peripheral shape of the package.

[0005]

In order to achieve the above object, according to the optical axis measuring method of an optical module of the present invention, an optical component is housed and a reference surface of a package constituting the optical module is used as a reference of an optical measuring system. After correcting perpendicular to the optical axis,
The displacement angle formed by the reference optical axis of the optical measuring system and the optical axis of the package is measured.

Preferably, the package is adjusted about an X-axis and a Y-axis which are orthogonal to the optical axis of the package and are orthogonal to each other, and the reference plane of the package is relative to the reference optical axis of the optical measurement system. To correct vertically. Also preferably, based on the position change of the light emitting point on the reference plane when the optical measurement system is brought into contact with the package along a reference optical axis, the reference optical axis of the optical measurement system and the package. Measure the displacement angle with the optical axis of.

After correcting the reference plane of the package forming the optical module to be perpendicular to the reference optical axis of the optical measurement system,
When the displacement angle formed by the reference optical axis of the optical measurement system and the optical axis of the package is measured, the displacement angle is accurately measured, and the quality of the package is determined. At this time, the package is orthogonal to the optical axis of the package, and the X-axis and the Y-axis which are orthogonal to each other.
If the reference plane of the package is corrected perpendicularly to the reference optical axis of the optical measurement system by adjusting the axis around the axis, the reference plane of the package is finely adjusted with respect to the reference optical axis of the optical measurement system.

Further, the reference optical axis of the optical measurement system and the optical axis of the package are determined based on the position change of the light emitting point on the reference plane when the optical measurement system is brought into contact with and separated from the package along the reference optical axis. When the displacement angle formed by is measured, the displacement angle can be accurately measured.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 shows a schematic configuration of an example of a measuring device used in the optical axis measuring method of an optical module according to the present invention.
The optical measuring unit 20 and the control unit 30 are provided.

The adjusting table 10 is an X-axis swivel stage 1
1, Y-axis swivel stage 12, X-axis linear stage 1
3 、 Y-axis linear stage 14 is Z in this order from the top
It is mounted on the shaft stage 15. The X-axis swivel stage 11 is a fixture 3 for detachably fixing the package 2.
Is attached to the upper part and is rotated about the X axis by the operation shaft 11a. The Y-axis swivel stage 12 is mounted with the X-axis swivel stage 11, and is rotated about the Y-axis orthogonal to the X-axis by the operation shaft 12a. The Y-axis swivel stage 12 is mounted on the X-axis linear stage 13 and is moved along the X-axis by an operation of the operation shaft 13a. The Y-axis linear stage 14 is the X-axis linear stage 1
3 is placed and moved along the Y axis by the operation of the operation shaft 14a. The Y-axis linear stage 14 is mounted on the Z-axis stage 15, and the X-axis stage 15 is operated by the operation shaft 15a.
It is vertically moved up and down along a Z axis orthogonal to the axis and the Y axis.

The optical measuring section 20 is an optical measuring system having an elevating stage 21, a length measuring sensor 22, and an infrared camera 23. The elevating stage 21 is a stage to which the length measuring sensor 22 and the infrared camera 23 are attached and which is moved up and down in the Z-axis direction, and is operated up and down by the operation shaft 21a. The length measurement sensor 22 uses the autofocus mechanism to package the package 2.
Is a sensor for measuring the distance to the reference plane 2a, and is connected to each of the operation shafts 11a to 15a and 21a via the control unit 30. The infrared camera 23 photographs the light emitting point of the package 2 with infrared rays having a wavelength of 0.8 to 1.6 μm and outputs the photographed image signal to the control unit 30.

The control section 30 drives the operation axes 11a to 15a and 21a of the optical measuring section 20 to automatically control the reference plane 2a of the package 2 so as to be perpendicular to the Z axis, and also the infrared camera. The position of the light emitting point of the package 2 in the X and Y axis directions based on the Z axis based on the image signal input from 23, the reference optical axis AS of the length measuring sensor 22 and the infrared camera 23 and the optical axis of the package 2. It is an electronic control unit (ECU) that calculates a displacement amount (angle) between and.

The optical axis measuring method of the optical module of the present invention is
It is performed as follows using the measuring device 1. First, after turning on the measuring device 1, the package 2 to be measured is fixed to the fixture 3 attached to the X-axis swivel stage 11. Then, the control unit 30 automatically performs the following measurement on the package 2 while controlling the operation of the measuring device 1.

First, the infrared camera 23 photographs the light emitting point of the package 2 and outputs an image signal of the light emitting point to the control unit 30. In the control unit 30, first, the center C of the package 2 is
(Refer to FIGS. 2 (b) and 2 (c)) and the light emitting point are measured for positional deviation, and then the control unit 30 performs each operation based on the image signal of the light emitting point input from the infrared camera 23. Axis 13
The drive signal is output to a and 14a, and the light emission point is the reference optical axis AS.
The X-axis linear stage 13 and the Y-axis linear stage 14 are driven so that

Next, the control unit 30 drives the length measuring sensor 22 to measure the distance to the reference surface 2a of the package 2 at a plurality of points (three or more points) as shown in FIG. The distance signal is output to the control device 30. Next, the control device 30 sets the X-axis swivel stage 11 and the Y-axis swivel stage 12 to X based on the input distance signal.
The amount of rotation to be rotated about the axis and the Y-axis is calculated respectively.

Then, the control device 30 outputs a drive signal to each of the operation shafts 11a and 12a based on the calculation result,
The X-axis swivel stage 11 and the Y-axis swivel stage 12 are rotated around the X-axis and the Y-axis, respectively, so that the distances to the reference plane 2a measured at a plurality of points become equal. As a result, the distances measured at a plurality of points from the length measuring sensor 22 to the reference surface 2a are equal, that is, the reference surface 2 of the package 2 is the same.
It is corrected so that a is perpendicular to the reference optical axis AS.

Thereafter, the control device 30 controls the operation shaft 21a.
2A, the elevating stage 21 is moved up and down in the Z-axis direction to measure the displacement angle between the reference optical axis AS and the optical axis of the package 2, as shown in FIG. That is, as shown in FIGS. 2 (b) and 2 (c), the control device 30 packages the infrared camera 23 at two positions where the distances between the length measuring sensor 22 and the reference surface 2a are L1 and L2, respectively. Based on the two emission points PL1 and PL2, X at both positions,
In addition to calculating the coordinates in the Y and Z axis directions, the angle formed by the optical axis of the package 2 with respect to the reference optical axis AS, that is, the displacement angle is calculated, and the result is stored in a memory and the light of the optical module of the present invention is calculated. The axis measurement method is complete.

The package 2 in which the displacement angle measured by the above optical axis measuring method and the positional deviation between the center C of the package 2 and the light emitting points PL1 and PL2 before this measurement is larger than a preset allowable range is It is rejected as a good product. On the other hand, the measured displacement angle and the positional deviation between the center C of the package 2 and the light emitting points PL1 and PL2 are within the allowable range.
Is, for example, as shown in FIG.
The optical module is automatically assembled by positioning with, mounting vertically, welding with YAG welding, and welding the fiber portion 6 to the condensing portion 5 in the same manner.

Here, as shown in FIG. 4, the package 2 includes a first condenser lens 2 inside a light emitting portion 2b arranged therein.
c and the light emitting element 2d are housed therein, and the reference surface 2a is open. The condensing unit 5 has a lens case 5a and a second condensing lens 5b. The lens case 5a has a reference surface 2
The second condensing lens 5b is mounted in the lens case 5a with a cylindrical body having a fitting portion 5c having a diameter smaller than the opening of a. Further, the fiber portion 6 has a fiber case 6a and an optical fiber 6b, a fitting portion 6c to be fitted into the end portion of the lens case 5a is formed at the end portion of the fiber case 6a, and the optical fiber 6b is provided in the fiber hole 6d. The edges are glued.

At this time, even if the measured displacement angle of the package 2 is zero, the optical axis of the package 2 and the reference optical axis AS of the length measuring sensor 22 and the infrared camera 23 may be displaced in parallel. . In this case, the light collecting section 5 to be mounted on the package 2 may be slightly moved in the direction orthogonal to the optical axis. By the way, the length measuring sensor 22 has an accuracy of 1/10 for obtaining the distance to the reference surface 2a of the package 2.
It has a position reproducibility of 1/1000 mm. From this, in the above-described method of the present invention, since the diameter of the reference surface 2a is 4.2 mm, the inclination error θ of the reference optical axis AS of the length measuring sensor 22 and the infrared camera 23 is calculated by the inverse trigonometric function. = 0.0136 °.

On the other hand, in the conventional measuring method in which the outer peripheral surface of the package, for example, the outer surface or the bottom surface is used as the reference surface and is fixed to the jig of the optical axis measuring device, the position reproducibility is 1/1.
Since the bottom length of the package is about 00 mm and the length of the package is 8.2 mm, the tilt error θ is calculated in the same manner.
It became 0.0699 °, and it was found that the method of the present invention measures the optical axis of the optical module with high accuracy.

In the above embodiment, the distance between the length measuring sensor 22 and the reference surface 2a of the package 2 was measured by the length measuring sensor using the autofocus mechanism, but the present invention is not limited to this. Needless to say, for example, in FIG.
It is also possible to use the reflection type laser displacement sensor 25 shown in FIG.

[0023]

As is apparent from the above description, according to the optical axis measuring method for an optical module of the present invention, when measuring the optical axis of the optical module, there is a gap between the outer peripheral surface of the package and the optical axis of the optical module. Even if there is, the position reproducibility of the package is excellent, and the optical axis of the optical module can be measured with high accuracy regardless of the outer peripheral shape of the package.

At this time, the package is adjusted around the X axis and the Y axis which are orthogonal to the optical axis of the package and are orthogonal to each other, and the reference plane of the package is perpendicular to the reference optical axis of the optical measurement system. Since the correction is performed, the reference plane of the package can be finely adjusted with respect to the reference optical axis of the optical measurement system. Also, based on the change in the position of the light emitting point on the reference plane when the optical measurement system is moved toward and away from the package along the reference optical axis, the displacement made by the reference optical axis of the optical measurement system and the optical axis of the package Since the angle is measured, the displacement angle can be accurately measured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a measuring apparatus that executes the method of the present invention.

FIG. 2 is an explanatory diagram illustrating a method of measuring a displacement angle formed by a reference optical axis of an optical measurement system and an optical axis of a package.

FIG. 3 is a perspective view illustrating a method of measuring the distance between the reference surface of the package and the optical measurement system and correcting the reference surface of the package perpendicular to the reference optical axis of the optical measurement system.

FIG. 4 is an exploded view showing a state of assembling an optical module by assembling another optical component in a package whose optical axis measurement has been completed, with these components being cross-sectioned.

FIG. 5 is a perspective view showing another example of a length measurement sensor that measures a distance between a reference plane of a package and an optical measurement system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measuring device 2 Package 2a Reference plane 3 Fixing device 5 Converging part 6 Fiber part 10 Adjusting stand 11 X-axis swivel stage 12 Y-axis swivel stage 13 X-axis linear stage 14 Y-axis linear stage 15 Z-axis stage 20 Optical measuring part 21 Lifting stage 22 Length measurement sensor 23 Infrared camera 30 Control unit AS Reference optical axis

Claims (3)

[Claims] 1. A reference optical axis of the optical measurement system and an optical axis of the package after correcting a reference surface of a package that houses an optical component and constitutes an optical module so as to be perpendicular to the reference optical axis of the optical measurement system. A method for measuring an optical axis of an optical module, which comprises measuring a displacement angle formed with an axis. 2. The package is adjusted about an X-axis and a Y-axis that are orthogonal to the optical axis of the package and are orthogonal to each other, and a reference plane of the package is relative to a reference optical axis of the optical measurement system. The method for measuring an optical axis of an optical module according to claim 1, wherein the optical axis is corrected vertically. 3. The reference optical axis of the optical measurement system and the reference optical axis of the optical measurement system based on a change in the position of a light emitting point on the reference surface when the optical measurement system is brought into contact with and separated from the package along the reference optical axis. The optical axis measuring method for an optical module according to claim 1, wherein the displacement angle formed by the optical axis of the package is measured.