JPH06201326A - Displacement measuring device - Google Patents

Abstract

PURPOSE:To accurately measure the displacement of an object of measurement, which has displacement measurement points extending in various directions, in a simple structure, and to carry out measurement in the same manner for an object whose displacement measurement points are tilted. CONSTITUTION:The light of a light projection part 3 is radiated on each lead 31a of an IC 31 having leads 31a extending in the four right directions. The dispersed light is detected by position detection elements 6a, 6b provided on the angular point with an angle of 45 degrees to the extending direction of the lead 31a with the light projection part 3 serving as a center. When a lead 31a of one side is to be measured after a lead 31a of another side of an IC 31, which crosses the former perpendicularly is measured, the relationship in terms of the projected and received light is the same between the light projection part 3 and the position detection elements 6a, 6b, and the light projection part 3 and the position detection elements 6a, 6b are moved only in the X-Y direction without being turned by 90 degrees, and the displacement of all of the leads 31a extended from the four sides of the IC 31 can thus be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement measuring device for optically measuring the displacement of a measuring object in a non-contact manner.

[0002]

2. Description of the Related Art FIG. 11 is a side view showing a conventional displacement measuring device, and FIG. 12 is a plan view thereof. As shown in these drawings, the sensor head 30 is arranged on the upper surface of the lead 31a of the IC 31, for example, which is the object of measurement, and the projection beam of the projecting section 32 using the LD light as the light source projects the lead 31a at right angles. To be done. The displacement of each lead 31a can be sequentially measured by moving the sensor head 30 or the IC 31 in the X direction in the figure. The scattered light from the lead 31a is generated by the position detecting element (PS) in the light receiving portion 33 in the sensor head 30.
D), the displacement of the lead 31a to be measured and the amount of received light indicate the floating condition of the lead 31a and the lead 31a.
Pitch measurements in between can be made.

[0003]

The surfaces including the projection beam and the optical axis of the light receiving lens are provided along the extending direction of the lead 31a. That is, in order to accurately detect the edge of the lead 31a, the surface including the light projection beam and the optical axis of the light receiving lens must be provided in parallel with the lead 31a.

However, an IC 31 having a large number of leads 31a often has a configuration of a QFP (Quad Flat Package) in which the leads 31a are provided on four sides of the IC 31, and therefore the displacement of the leads 31a on the other sides is measured as it is. , The plane including the projection beam and the optical axis of the light receiving lens is orthogonal to the lead 31a by 90 degrees, and abnormal output is likely to occur near the edge of the lead 31a, as shown in FIG.
An abnormal output as shown in (c) is generated, and accurate displacement measurement cannot be performed.

Therefore, conventionally, in order to measure the lead 31a on one side of the IC31 and then measure the lead 31a on the other side orthogonal to the IC31, the IC31 should be placed along the lead 31a.
Alternatively, the sensor head 30 has to be rotated by 90 degrees, which requires the precision of the rotating mechanism, which increases the cost and causes a problem that the measuring tact becomes long due to the rotation.

In the above description, the light projecting section 32 emits a light projecting beam at a right angle to the object to be measured, and the light receiving section 33 receives scattered light. However, the light projecting beam of the light projecting section 32 is also measured. There is also a configuration that irradiates the object diagonally and receives specularly reflected light with a light-receiving lens installed at an angle that is symmetrical with the irradiation direction with respect to the normal line of the measurement target.This configuration also causes the same problem. ing. Further, the above-mentioned measurement target has been described by taking as an example the one in which the leads 31a are provided on the four sides of the IC 31, but the wiring pattern on the printed circuit board also extends in four directions, and the displacement of this wiring pattern is measured. The same problem occurred when doing.

Further, as shown in FIG. 13, the lead 31a of the IC 31 has a joint portion 31b inclined by a predetermined angle α, and the joint portion 31 of the conventional sensor head 30 is formed.
When the displacement of b (floating of the lead 31a) is measured, the specularly reflected light is directly received, and the light receiving level becomes high, so that there is a problem that it is necessary to widen the dynamic range of the processing system. Since the joint portions 31b have the same height, when the IC 31 is mounted on the printed circuit board,
This enables stable joining, and this joining portion 31b
It is necessary to accurately measure the height of.

The present invention has been made in view of the above problems, and is capable of accurately measuring the displacement of a measuring object having displacement measuring points extending in different directions, and having a simple structure and low cost. Is intended to provide.
It is another object of the present invention to provide a displacement measuring device capable of accurately measuring the floating even when the joint portion of the IC lead is inclined by a predetermined angle.

[0009]

In order to achieve the above object, the displacement measuring apparatus of the present invention is, in the claims, a projecting section for irradiating a measuring object having a plurality of non-parallel edges with a projecting beam for measurement. And a plurality of pairs of light receiving portions configured by a light receiving lens and a position detecting element arranged at a position of a point object excluding the edge with respect to each edge of the measurement object, and calculating the output of the position detecting element, And a calculation unit that outputs the displacement amount of the measurement target.

Further, according to a second aspect of the present invention, each of the light projecting portion for irradiating the measuring object having a plurality of edges which are not parallel with each other with the projection light beam for measurement, and the multi-axis two-dimensional coordinate formed by the axis parallel to the edges. A light-receiving unit composed of the same number of light-receiving lenses and position detection elements arranged in the quadrant space except on the edges,
An arithmetic means for calculating an output of the position detecting element and outputting a displacement amount of the measurement target is provided.

[0011]

The light projecting unit 3 irradiates the lead 31a as an edge of the measurement object 31 with a light projecting beam, the scattered light is received by the light receiving units 4a and 4b, the displacement amount of the lead 31a is detected, and the calculating means is calculated. Calculation processing is performed at 7. Measurement target 31 is 4
The leads 31a extend in directions orthogonal to each other at 90 degrees from each other, and the light receiving portions 4a and 4b are arranged at point-symmetrical positions with respect to the leads 31a except on edges.
It is possible to always have the same light emitting / receiving arrangement relationship with respect to the extending direction of all the leads 31a, and to simply move the light emitting unit 3 and the light receiving units 4a, 4b in the XY directions without rotating. It is possible to measure the amount of displacement of all the leads 31a only by using.

[0012]

1 is a plan view showing a first embodiment of a displacement measuring apparatus of the present invention. The edge of the IC 31 as the measurement target, that is, the lead 31a has a Q extending to four sides as in the conventional case.
It is of the FP type.

The sensor head 1 is attached to each lead 31a.
Is movable in the X direction or in the Y direction orthogonal to the X direction. The sensor head 1 is provided with a light projecting section 3 at the center thereof, and a light projecting beam of the light projecting section 3 is directed to the lead 31a.

With the light projecting portion 3 as the center, the leads 31a
Light-receiving portions 4a and 4b are provided on both sides of the light-receiving portion 4a at positions inclined by 45 degrees with respect to the extending direction of the lead 31a (either the XY direction). The optical axes of the light receiving lenses of the light receiving sections 4a and 4b and the projected beam are provided on the same plane. The sensor head 1 is configured to be movable in the X direction or the Y direction by a moving mechanism (not shown). The sensor head 1 is fixed and the moving mechanism is IC3.
1 may be moved in the X-Y directions.

FIG. 2 is a schematic diagram showing the inside of the sensor head 1. The light projecting beam emitted from the LD of the light projecting unit 1 vertically strikes the lead 31a, and this scattered light passes through the light receiving lenses 5a and 5b of the light receiving units 4a and 4b and onto the position detection elements (PSD) 6a and 6b. Focus on. The position detecting elements 6a and 6b are arranged at positions symmetrical with respect to the projected beam and are connected to the calculating means 7 in the subsequent stage.

Since the image of the light spot on the one light receiving element 6a is inverted with respect to the image of the light spot on the other light receiving element 6b when the displacement direction is taken as a reference, as indicated by the thick arrow in the figure. The change in the center of gravity of the image of the light spots on the two light receiving elements 6a and 6b, which occurs when the surface state changes, acts in the directions canceling each other as indicated by the arrow, so that accurate measurement can be performed. Further, since the light projecting / receiving surface is installed obliquely with respect to the edge of the lead 31a, there is an advantage that the specular reflection light is not received at the edge portion and the dynamic range of the processing circuit can be narrowed.

Next, FIG. 3 is a block diagram showing the electrical construction of the arithmetic means 7 provided in the sensor head 1. Outputs from both ends of each of the position detecting elements 6a and 6b are respectively amplified by amplifiers 8a to 8d. The outputs of the amplifiers 8a and 8b are input in parallel to the subtractor 10a and the adder 11a to obtain a subtraction output and an addition output. Similarly, the amplifiers 8c and 8
The output of d is also subtracted and added by the subtractor 10b and the adder 11b.

The subtracted outputs of the subtractors 10a and 10b are combined by the combiner 14, and the added outputs of the adders 11a and 11b are combined by the combiner 16. The output of the combiner 16 is used as the received light amount information of the measurement target. These synthesizers 1
The outputs of 4 and 16 are subjected to division processing by the divider 18, and the position information output of the measurement target is obtained.

In the above structure, the position detecting elements 6a, 6a
b is disposed at a position symmetrical with respect to the projection beam, and the projection / reception surface is inclined with respect to the edge of the lead 31a, so that the mutual outputs cancel out the change in the position of the center of gravity of the point spot due to the surface state. In addition to working as described above, it is made less susceptible to secondary reflection from the adjacent lead 31a. Also, the dynamic range of the processing system can be narrowed.

Therefore, when the sensor head 1 moves and the displacement is measured from one edge 31c to the other edge 31d of a certain lead 31a as shown in FIG. 4 (a), the displacement obtained from one light receiving portion 4a. The output has the characteristics shown in FIG. 7B, and the other light receiving section 4b
The displacement output obtained from the above has a characteristic as shown in FIG. 7C, but the displacement output obtained by combining the outputs of the two light receiving portions 4a and 4b has the characteristic shown in FIG. Accurate measurement can be performed. This output is
This is the output of the divider 18.

The sensor head 1 includes light receiving portions 4a and 4b.
Is a plane and is inclined by 45 degrees with respect to any of the XY directions. Therefore, the leads 31a on one side of the IC 31 are sequentially X-rayed.
Lead 31 extending to the other side of IC 31 (direction different from the one side by 90 degrees) after moving in the direction to measure the displacement amount.
As for a, the displacement amount can be similarly measured only by moving the sensor head 1 in the Y direction, as indicated by the one-dot chain line in FIG. At this time, the light receiving portions 4a and 4b of the sensor head 1 have an inclination of 45 degrees with respect to the lead 31a, and can measure with the same accuracy.

Next, FIG. 5 is a plan view showing a second embodiment of the displacement measuring apparatus of the present invention. As shown in the figure, the sensor head 1 is provided with a light projecting section 3 at the center thereof.
The projection beam of the light impinges on the lead 31a perpendicularly. With the light projecting portion 3 as the center, on both sides of the lead 31a, 4 with respect to the extending direction of the lead 31a (either the XY direction).
Two light-receiving units 4 with a predetermined interval at a position inclined by 5 degrees
a, 4b, 4c and 4d are provided. In addition, each light receiving unit 4a
4d are respectively arranged at an angle of 90 degrees on a plane, and have respective light receiving lenses 5a, 5b, 5c, 5d and position detecting elements 6a, 6b, 6c, 6d.

FIG. 6 is a block diagram showing the electrical construction of the calculating means 17 of the second embodiment. Each light receiving unit 4a-4d
Outputs of the position detection elements 6a to 6d provided in the are amplified by amplifiers 8a to 8h. The outputs of the amplifiers 8a and 8b are
The subtracter 10a and the adder 11a are input in parallel to obtain a subtraction output and an addition output. Similarly, the outputs of the amplifiers 8c to 8h are also the subtractors 10b, 10c, 10d and the adder 11
Subtraction output and addition output are performed by b, 11c, and 11d.

The subtracted outputs of the subtractors 10a to 10d are combined by the combiner 14, and the added outputs of the adders 11a to 11d are combined by the combiner 16. The output of the combiner 16 is used as the received light amount information of the measurement target. These synthesizers 1
The outputs of 4 and 16 are subjected to division processing by the divider 18, and the position information output of the measurement target is obtained.

In the configuration of this embodiment, two sets of light receiving portions 4a to 4d are provided at a predetermined interval in the extending direction of the lead 31a. Therefore, like the IC 31 shown in FIG. Even if the joining portion 31b is inclined by a predetermined angle, the amount of specular reflection does not enter the light receiving portion.
Since the dynamic range of the processing system can be narrowed and the light emitting and receiving surface is inclined with respect to the edge of the lead 31a, the light is reflected by the lead 31a and the adjacent lead 31a.
It is less affected by the light reflected by a, and as a result, it becomes possible to measure the displacement amount of the joint portion 31b of the lead 31a.

Further, according to the displacement measuring devices of the first and second embodiments, the leads 31a, 31aa adjacent to the IC 31 are adjacent to each other.
Even if the pitch interval between them is narrow, the adjacent lead 31aa
It is possible to prevent the influence of the secondary reflected light reflected by.
That is, as shown in FIG. 7, when the spacing between the leads 31a is a narrow pitch, the projection beam of the light projecting unit 3 leads to the leads 31a.
When the edge 31c or 31d is irradiated with a part B of the light, it is reflected in the direction of the adjacent lead 31aa, and if the secondary reflected light C of this lead 31aa is incident on the light receiving part 4, the measurement accuracy is affected. However, according to the above-described configuration in which at least one pair of light receiving portions 4a and 4b are symmetrically arranged with respect to the light projecting portion 3, the secondary reflected light C and C ′ are When the outputs from the light receiving sections 4a and 4b are incident on the position detection elements 6a and 6b and combined with each other, they act in the directions of canceling each other, so that the influence of the secondary reflected light can be prevented.

Also in the second embodiment, as in the previous embodiments, the sensor head 1 is moved in the XY directions by the moving mechanism, and the leads 3 extended from the sides orthogonal to the IC 31.
The displacement amount can be measured by moving the sensor head 1 or the IC 31 only in the XY direction with respect to 1a without rotating.

Further, in each of the above-mentioned embodiments, the measurement target is 4
Although the IC 31 having the leads 31a on the sides has been described as an example, in the case where the wiring pattern on the printed circuit board extends in four directions as a measurement target, the same applies to the case of measuring the displacement of the wiring pattern. The effect of can be obtained.

Next, FIG. 8 is a plan view showing a third embodiment of the displacement measuring apparatus of the present invention. As shown in the figure, the sensor head 1 is provided with a light projecting section 3 at the center thereof.
The projected light beam of the light impinges on the edge 41a of the measuring object 41 perpendicularly. The measurement target 41 is formed in a polygonal shape on a plane as shown in FIG. 9, and in this embodiment, a triangular electronic component is mounted on a printed circuit board.

With the light projecting section 3 as the center, the measurement target 41
Corresponding to the shape of the edge 41a of the three light receiving portions 4a, 4a
b and 4c are provided. The light receiving portions 4a, 4b, 4c are arranged in the same number in each quadrant space of the multi-axis two-dimensional coordinate formed by the axis parallel to the edge 41a except on the edge 41a. The light receiving portions 4a, 4b, 4c are provided on the same circumference with the measurement point of the measurement target 41 by the light projecting portion 3 as the center, and the angles from the respective edges 41a are the same.

9 (a) and 9 (b) respectively show a measurement target 41.
FIG. 4 is a plan view and a side view showing the measurement target 41.
Is configured as an electronic component provided on a printed circuit board, for example. The measurement target 41 has an edge 41a as shown in FIG.
As described above, it is formed in a triangular shape. Therefore,
3 for each edge 41a for one measurement object 41
Individual light receiving portions 4a, 4b, 4c are provided.

Therefore, as shown in the operation diagram of FIG.
When the sensor head 1 moves in the X direction on the measurement target 41, the Z direction output corresponding to the displacement amount of the measurement point portion in the X direction by the light projecting unit 3 is output in the Z direction as shown in FIG. , 4bx, 4cx. Further, when moving in the Y direction, an output in the Z direction corresponding to the amount of displacement in the Y direction of the measurement point portion is output as shown in FIG.
Obtained from aY, 4bY, 4cY. These light receiving parts 4
The outputs of a, 4b and 4c can be easily calculated by using the same circuit as the calculating means 7 and 17 and having three inputs.

Each of the movements in the XY directions moves only once, and does not move the entire part of the measuring object 41. Therefore, the measurement is performed as shown in FIGS. Although the latter signal becomes a partial signal, it is possible to obtain the displacement amount corresponding to the entire outer shape by moving the entire portion in accordance with the movement in the XY directions to the outer shape of the measurement target. Become.

Further, as shown in FIG. 8, the light receiving portions 4ab, 4a are provided on the sides of the three reference light receiving portions 4a, 4b, 4c.
c, ... By additionally arranging 4 cc, the received light amount can be averaged and the displacement measurement can be made highly accurate. Further, if the same number of light receiving portions are arranged in each quadrant space of the multi-axis two-dimensional coordinate parallel to the edge 41a in conformity with the shape of the measuring object 41, the displacement amount of the polygonal measuring object 41 is further reduced. Can be measured accurately.

[0035]

According to the first aspect of the present invention, the projection beam of the projection unit is received by the light receiving unit arranged at the position of the point object other than the edge of each measuring object, and is calculated by the calculating means. Since the calculation is performed, the same light emitting and receiving arrangement can be performed on any of the leads that are orthogonal to each other, and even if the sensor head provided with the light emitting unit and the light receiving unit is not rotated, The amount of displacement can be measured, and the effect can be obtained with a simple configuration. Further, even for an IC provided with a narrow lead pitch, it is possible to prevent the influence of the secondary reflected light of the adjacent leads and measure the displacement amount with high accuracy.

According to the second aspect, the projection beams of the projection unit are arranged in the same number in each quadrant space of the multi-axis two-dimensional coordinate formed by the axis parallel to the edge of the measurement object except the edge. Since the light receiving unit receives the light and the calculation unit calculates the displacement, the displacement amount can be accurately measured even when the measurement target has a polygonal shape.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of a displacement measuring device of the present invention.

FIG. 2 is a schematic diagram showing the inside of the sensor head of the first embodiment.

FIG. 3 is a block diagram showing a calculation means of the first embodiment.

FIGS. 4A to 4D are diagrams showing output signals of respective parts corresponding to the measurement state of the leads.

FIG. 5 is a plan view showing a sensor head according to a second embodiment of the displacement measuring device of the present invention.

FIG. 6 is a block diagram showing a calculation means of the second embodiment.

FIG. 7 is a diagram showing a narrow pitch lead measurement state by the displacement measuring device of the present invention.

FIG. 8 is a plan view showing a sensor head according to a third embodiment of the displacement measuring device of the present invention.

9A and 9B are a plan view and a side view showing a measurement target of the third embodiment.

10A and 10B are diagrams showing outputs corresponding to the operating state of the third embodiment.

FIG. 11 is a side view showing a conventional displacement measuring device.

FIG. 12 is a plan view of the device.

FIG. 13 is a view showing an IC lead in which a joint portion is inclined at a predetermined angle.

[Explanation of symbols]

1 ... Sensor head, 3 ... Emitter, 4a-4d ... Light receiver,
5a to 5d ... Receiving lens, 6a to 6d ... Position detecting element,
7, 17 ... Computing means, 8a-8d ... Amplifier, 10a-1
0d ... Subtractor, 11a-11d ... Adder, 14, 16 ...
Combiner, 18 ... Divider.

Claims (2)

[Claims] 1. A light projecting section (3) for irradiating a measuring light beam having a plurality of edges which are not parallel to each other, and a point object for each edge of the measuring object except for the edge. A plurality of pairs of light receiving portions (4a, 4b), (4a to 4d) each composed of a light receiving lens and a position detecting element arranged at positions
A displacement measuring device comprising: and a calculating means (7), (17) for calculating an output of the position detecting element and outputting a displacement amount of the measurement target. 2. A light projecting unit for irradiating a measurement light beam having a plurality of edges that are not parallel to each other, and an edge in each quadrant space of multiaxial two-dimensional coordinates formed by axes parallel to the edge. A light-receiving unit composed of the same number of light-receiving lenses and position detection elements, except for the above, and calculation means for calculating the output of the position detection elements and outputting the displacement amount of the measurement target. Displacement measuring device.