JP2588597Y2 - Optical length measuring device - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention measures the inner diameter of a ring-shaped work, the outer diameter of a block-shaped work, and the like, and measures the distance between measurement walls using an optical system. It concerns the device.

[0002]

2. Description of the Related Art As a device for optically measuring the distance between wall surfaces such as the inner diameter of a ring-shaped work 1 and the outer diameter of a block-shaped work 1, the work side is connected to an observation optical system as shown in FIG. Moving optical length measuring devices are known.

[0003] This basic configuration is disclosed in Japanese Patent Application No. 5-1 of the present applicant.
As described in No. 69355, a mechanical movement mechanism 3 that can move a relative position between a plurality of measured positions P1 and P2 of the work 1 and an observation optical system 2 having a length measurement camera as an observation unit 6 is provided. A moving amount measuring device 4 for measuring a relative position moving amount by the mechanical moving mechanism 3, and a projecting unit 5 for projecting a predetermined projected image onto the measured positions P 1 and P 2 of the work 1.
Are provided, and the reflection images R1 and R of the projection image by the projection unit 5 are provided.
An observation unit 6 for observing the object 2 via the observation optical system 2 is provided on a side opposite to the projection unit 5 with the work 1 as a boundary, and the observation unit 6 allows a plurality of positions P1 and P2 of the work 1 to be measured. The length is measured as a relative position movement amount measured by the movement amount measuring device 4.

Therefore, in the measurement by the optical length measuring device, as shown in FIG. 1, a reflection image R1 captured by a CCD camera (observation unit 6) at one measurement position P1 of a work 1 is specified on a monitor 7 at a specific position. The stage (mechanical moving mechanism 3) on which the work 1 is placed is moved so as to be positioned at the center of the two index lines 9 and 10 provided at the position, and when the position is correct, the amount of movement is measured. The measuring device 4 (linear counter) is set to 0, and then the workpiece 1 is moved as shown in FIG. 2 so that the reflection image R2 at another measurement position P2 is correctly positioned again between the index lines 9 and 10. The moving distance of the counter 4 is read to determine the length between the wall surfaces P1 and P2 of the work 1.

The work 1 can be fixed and the observation optical system 2 can be moved. As shown in FIG. 3, a specific example is shown in FIG. The optical system (the optical system on the projection side and the observation side) is arranged upside down in the movable optical unit 50 shown, and the mechanical movement amount is measured by the movement amount of the optical system. Is a method suitable when it is difficult to move the work 1.

[0006]

However, in such a conventional optical length measuring device, these index lines 9.1 and 9.1 are used.
The work of setting the reflection images R1 and R2 at the center of the
Because of the above visual judgment, it is difficult for an ordinary worker to set the center correctly, and the setting position is set to a different position each time the measurement is performed. As a result, the repeatability of the measurement deteriorates (2 to 2). 5 μ).

[0007] On the other hand, if the skilled worker is careful and careful setting, measurement can be performed with a repetition accuracy of 0.25 μm. However, if many workpieces are measured for a long time, the variation becomes large due to eye fatigue, and this accuracy becomes large. There were drawbacks.

Therefore, there has been a demand for a method of improving the accuracy even for a general worker having a large setting error to that of a skilled worker, and for preventing the skilled worker from deteriorating the accuracy due to fatigue.

According to the present invention, an excellent optical measurement method capable of improving the repetition accuracy by recognizing the error on the hardware side and correcting the machine movement amount even if such a large artificial setting error occurs. It is intended to provide a long device.

[0010]

The gist of the present invention will be described with reference to the accompanying drawings.

There is provided a mechanical moving mechanism 3 for moving the relative positions of a plurality of measured positions P1 and P2 of the work 1 and the observation optical system 2, and measures a relative position moving amount by the mechanical moving mechanism 3. And a projecting unit 5 for projecting a predetermined projected image onto the measured positions P1 and P2 of the work 1
Are provided, and the reflection images R1 and R of the projection image by the projection unit 5 are provided.
2 is provided on the opposite side of the projection unit 5 with the work 1 as a boundary, the observation unit 6 including a length measuring camera for observing the work 1 via the observation optical system 2. In an optical length measuring device that measures the length between the measurement positions P1 and P2 as a relative position movement amount measured by the movement amount measuring device 4, an index 30 is displayed on a monitor 7 that captures the reflection images R1 and R2. The number of imaging pixels in the length measurement direction of the length measurement camera of the observation unit 6 is set to at least 10 or more, and the magnification of the observation optical system 2 is set to several times or more, so that the reflected image can be obtained with high resolution. A central portion 13 of R1 and R2 is configured to be imaged, and a detector 31 is provided for extracting an output of a specific area from the imaged output of the length measuring camera. The output in the detector 31 is fetched into a memory. Calculate the output of Reflected image in 1 · P2 R1 · R2
And a difference calculating means for calculating a difference distance between the center position of the center pattern 13 and the center position of the detecting section 31. The output of the moving amount measuring device 4 and the output of the difference calculating means are calculated. The optical length measuring apparatus according to claim 4, further comprising a correction calculating means for correcting the measured value of No. 4.

[0012]

The reflection image R1 of the projection image projected on one measured position P1 (one wall surface) of the work 1 is almost aligned with the center of the detection unit 31 on the monitor 7 of the observation unit 6 using the index 30 as a guide. For example, when the command control means is operated, the mechanical movement amount (relative position movement amount) KL is reset to 0, and at the same time, the image in the detection unit 31 is taken into the memory.

The center position of the reflected image R1 is immediately obtained by the center detecting means based on the fetched DATA, and the difference D1 from the center of the detecting section 31 is output by the difference distance calculating means and stored in the difference distance memory. Is done.

Thereafter, a reflection image R2 of the projected image projected on the other measured position P2 (the other wall surface) of the workpiece 1 again.
Is approximately adjusted to the center of the detection unit 31 on the monitor 7 in the same manner, and when the command control means is operated again, the mechanical movement amount KL
Are stored in the machine movement amount memory.

Subsequently, the image in the detecting section 31 is fetched into the memory, and the center position of the reflected image R2 is immediately obtained by the center detecting means based on the fetched DATA, and the difference from the center of the detecting section 31 is obtained. D2 is output by the difference distance calculation means and stored in the difference distance memory. The output of the machine movement amount memory and the difference distance memory, and subsequently the correction calculation means,
Correction calculation of RL = KL − ((D1−D2) × K) is performed, and as a result, a correct measurement value is displayed on the display unit on the monitor 7, for example.

Note that K in the above equation is a correction constant adjusted according to various conditions.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure and operation of the optical length measuring apparatus of this embodiment to which the present invention is applied are described in Japanese Patent Application No. 5-1 of the present applicant.
No. 69355, and a brief description thereof is omitted in the description of the prior art.

Hereinafter, only the gist of the present embodiment will be described.

As shown in FIG. 4, in order to easily find the center of the central pattern 13 of the reflection images R1 and R2, the reflection images R1 and R2 are used.
G between the light-transmitting portions at equal intervals on both sides of the central pattern 13 of R2
Side band patterns 32 and 33 are provided in the measurement direction via 1 · G2.

More specifically, the patterns (center pattern and side band pattern) are formed in black on the glass surface of the light source reticle provided in the projection unit 5, and this pattern is projected on the work 1 to obtain reflected images R1 and R2. .

Next, if a CCD camera (camera for length measurement) having many pixels in the measurement direction is used, the resolution is increased and the reflection image R
Although the center of the 1 · R2 center pattern 13 can be easily found with high accuracy, it is expensive and the number thereof is limited in terms of practical use.

Here, as shown in FIG. 5, since the object having a picture element pitch of about 10 μm is used, the central pattern 13 of the reflected images R1 and R2 is picked up by more pixels.
The magnification of the observation optical system 2 is increased, and the enlarged image is projected on the element surface.

Here, the center pattern 13 is imaged with approximately 30 pixels by 50 times magnification to increase the resolution. In order to improve the measurement accuracy compared to the conventional example, it is desirable that the magnification is at least 5 times or more and the center pattern 13 is imaged with 10 or more pixels.

A detection section 31 for extracting an output of a specific area from the output of the CCD camera is provided. In this embodiment, the area of the detection section 31 is displayed on a monitor 7 as a window frame, and the window frame index and its center are displayed. The index is referred to as index 30. The output in the detection unit 31 (detection window) is configured to be taken into a plurality of memories.

As shown in FIG. 6, a detection unit 31 of 26 .mu.s in horizontal and 20 H in vertical is provided, and the output of this detection unit 31 is used as position information for 256 positions in the horizontal direction, 20 positions in the vertical direction, and 256 levels in depth as output level information. Is stored in the memory as DATA.

Next, there is provided a center detecting means for calculating the output of the memory to obtain the center position of the center pattern 13 of the reflection images R1 and R2 at the measurement position, and furthermore, a difference between the center position and the center position of the detection unit 31. A difference calculation means for obtaining a distance is provided.

An output in the detecting section 31 is obtained by reading out each of the memories. (Actually, the addition operation in the horizontal direction and the vertical direction is performed and omitted here, but the center position is obtained by comparing with a model pattern signal learned in advance.)
Here, in order to avoid confusion of the description, the description will be made in a simple manner.

As shown in FIG. 7, the reproduced output is at a LOW level in the side band patterns 32 and 33 and the center pattern 13 in the horizontal direction, and a HIGH level signal is obtained at intervals G1 and G2. Therefore, the positions of these two HIGH level signals are determined on the sweep time axis, and the center thereof is the reflected image R1.
The center position can be known because it is a half of the center pattern 13 of R2.

The position of the center of the detector 31 is set in advance so as to coincide with the optical axes Z1 and Z2 of the observation optical system 2.

When a skilled person measures carefully, the reflection images R1 and R
The center of 2 is made to coincide with the center of the detection unit 31, but tends to be slightly shifted when a general worker or fatigue is advanced.

The difference D between the central position of the reflection lines R1 and R2 obtained by the central detecting means and the predetermined central position of the detecting unit 31 (the position obtained via the sweep time axis).
Ask for.

This difference is calculated as the difference D1 between the position of one reflected image R1 at the start of measurement and the difference D2 between the position of the other reflected image R2 and 2
There is a difference.

Next, there is provided a correction calculating means for calculating the output of the counter (mechanical moving mechanism 3) for measuring the mechanical moving amount, that is, the mechanical moving amount KL and the difference distances D1 and D2 to correct the measured value. .

In the past, the mechanical movement amount KL was simply used as a measured value. However, in practice, the difference D1 and D2 between the positions due to an incorrect setting judgment by the operator added to the measured value, thereby increasing the measurement error.
Thus, the correct measured value RL is:

RL = KL− (D1−D2) Therefore, by providing this correction operation unit, a correct value can be obtained even in the case of measurement with many errors.

Actually, the correction coefficient K is further added to the above equation in consideration of various characteristics of the measuring apparatus (for example, the amount of movement of the reflected image due to optical magnification, etc.), and the following is obtained.

RL = KL − ((D 1 −D 2) × K) In order to further increase the measurement accuracy, K 1, K 2, K 1, K 2
... And a plurality of Kns are prepared, and these are selected and used as operation coefficients.

With the above configuration, as shown in FIGS. 8 and 9, a reflection image R1 of a projection image initially projected on one measured position P1 (one wall surface) of the work 1 is formed on the observation unit 6 as shown in FIG.
When the command control means is activated, the mechanical movement amount (relative position movement amount) KL is reset to 0, and the detection is simultaneously performed. The image in the section 31 is taken into the memory.

The center position of the reflected image R1 is immediately obtained by the center detecting means based on the fetched DATA, and the difference D1 from the center of the detecting section 31 is output by the difference distance calculating means and stored in the difference distance memory. Is done.

Thereafter, a reflection image R2 of the projection image projected on the other measured position P2 (the other wall surface) of the work 1 again.
Is approximately adjusted to the center of the detection unit 31 on the monitor 7 in the same manner, and when the command control means is operated again, the mechanical movement amount KL
Are stored in the machine movement amount memory.

Subsequently, the image in the detecting section 31 is fetched into the memory, and the center position of the reflected image R2 is immediately obtained by the center detecting means based on the fetched DATA, and the difference from the center of the detecting section 31 is obtained. D2 is output by the difference distance calculation means and stored in the difference distance memory. The output of the machine movement amount memory and the difference distance memory, and subsequently the correction calculation means,
Correction calculation of RL = KL − ((D1−D2) × K) is performed, and as a result, a correct measurement value after correction (“1.0
00 ”) is displayed on the display unit on the monitor 7, for example.

Incidentally, the reflected images R1 and R2 are erroneously detected by the detection unit 31.
In the conventional example, as shown in FIG. 10 showing the measurement result before correction (according to the conventional example) when it does not coincide with the center of the (index window) and the measurement result after correction based on the present embodiment, ±
An error range of 5μ results in ± 0.2μ, and high-precision measurement can be realized by a simple operation of merely adjusting the reflection images R1 and R2 to the index 30 (center of the detection window).

[0043]

According to the present invention, even in the case of an erroneous setting of ± 5 μm such that either end of the center pattern of the reflection image is located at the center of the detection window, the present invention is effective. Within the range of 0.2 μ. This indicates that the measurement can be easily and correctly performed even by a non-expert.

Furthermore, even a skilled person does not need to carefully adjust the image by finely moving the image right and left in the vicinity of the center, so that the measurement can be performed at a speed of about four times or more.

Since the measurement can be performed with less variation, the operation of calculating the average by measuring the average ten times or more to obtain the measured value is unnecessary, and the correct measured value can be obtained only by measuring once.

In addition, accurate measurement can be performed even by a skilled person, when the eyes are tired, or by an elderly person with poor vision.

Further, since the setting is easy, it is possible to measure a large amount of work for a long time. In addition, the fatigue of the worker is reduced.

Further, since the measurement can be easily performed even by a non-expert in general work, labor costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an optical length measuring device in a state where one measured position is observed.

FIG. 2 is a schematic explanatory view of an optical length measuring device in a state where the other measured position is observed.

FIG. 3 is a schematic explanatory view of an optical length measuring device showing an example in which a work side is fixed and an optical system side is movable.

FIG. 4 is an explanatory diagram showing an observation state of a reflection image on a monitor according to the embodiment.

FIG. 5 is an explanatory diagram showing the resolution of a length-measuring camera (CCD camera) of the observation unit of the present embodiment.

FIG. 6 is an explanatory diagram illustrating an imaging capability of a detection unit according to the present embodiment.

FIG. 7 is a diagram illustrating the operation of a center detection unit that detects the center position of the reflection image according to the present embodiment.

FIG. 8 is a flowchart illustrating an operation procedure of the present embodiment.

FIG. 9 is a schematic configuration diagram of the present embodiment.

FIG. 10 is an explanatory diagram comparing measured values with a conventional example of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Workpiece 2 Observation optical system 3 Mechanical movement mechanism 4 Movement amount measuring device 5 Projection part 6 Observation part 7 Monitor 13 Center pattern 30 Index 31 Detection part P1 Measurement position P2 Measurement position R1 Reflected image R2 Reflected image

Claims (1)

(57) [Scope of request for utility model registration] 1. A moving amount measuring device for providing a mechanical moving mechanism capable of moving a relative position between a plurality of measured positions of a workpiece and an observation optical system, and measuring a relative position moving amount by the mechanical moving mechanism. A projection unit for projecting a predetermined projection image at a position to be measured on the workpiece, and a length measurement camera or the like for observing a reflection image of the projection image by the projection unit via the observation optical system. An optical unit for providing an observation unit on a side opposite to a projection unit with a work as a boundary, and measuring a length between a plurality of measured positions of the work by the observation unit as a relative position movement amount measured by the movement amount measuring device. In the type length measuring device,
An index is provided on a monitor that captures the reflection image, and at least 10 pixels in the length measurement direction of the length measurement camera of the observation unit are set.
And the magnification of the observation optical system is set to several times or more, so that the central pattern of the reflection image is captured with high resolution. A detection unit for extracting an output of a specific area is provided, the output in the detection unit is fetched into a memory, the output of the memory is calculated, and the difference between the center position of the central pattern of the reflection image at the measured position and the center position of the detection unit is calculated. The difference calculation means to be obtained is provided,
An optical length measuring device, further comprising a correction operation unit that calculates an output of the movement amount measurement device and an output of the difference calculation unit to correct a measurement value of the movement amount measurement device.