JPS60253813A - Non-contact displacement detection apparatus - Google Patents

Abstract

PURPOSE:To attain miniaturization, wt. reduction and the enhancement of accuracy while enlarging a measuring range, by guiding the beam of laser for visible rays of a first apparatus to a second apparatus equipped with laser for detection beam through a beam transmission line and setting both beams on the same optical axis to irradiate an article to be detected while detecting reflected beam therefrom. CONSTITUTION:First and second apparatuses 20, 30 are coupled by an optical fiber 40 in a spacially separated state and He-Ne gas laser 21 for visible rays, a condensing lens 22, a modulation drive circuit 23 and an operation circuit 14 are provided to the apparatus 20 while semiconductor laser 31 emitting detection beam, collimation lenses 32, 33, a dichroic mirror 34, a condensing lens 4 and an optical semiconductor position detector 5 are provided to the apparatus 30. Then, beam from the laser 21 is allowed to transmit through the mirror 34 through the fiber 34 and set on the same optical axis as the modulation beam of the beam from the laser 31 to irradiate an object 10 to be detected while the reflected beam therefrom is detected by the detector 5 and further detected in synchronous relation to the modulation of the laser 31 by the circuit 14 to be displayed on a display part 15.

Description

[Detailed description of the invention] [Technical field of invention] The present invention is applicable to, for example, industrial products and living bodies that are easily deformed.

Regarding non-contact displacement detection devices that use lasers, which are used to measure the shape of objects such as cultural properties, the thickness of objects on production lines, and the size and position of scratches on objects, we especially use visible lasers. The present invention relates to a non-contact displacement detection device that enables visual observation of measurement points using light.

[Prior art]

Conventionally, various devices have been used to irradiate a target object with a laser beam, detect the light reflected and scattered by the target object, and detect the displacement of the target object from changes in its position and intensity. In that case, it may be required for operational reasons or to prevent danger that the irradiation point and measurement points t and a can be easily visually confirmed.

Figure 1 shows an example of the configuration of a conventionally used device of this kind, which emits visible laser light with a wavelength of 632.8 nm.
e-Ne gas laser 1, acousto-optic modulator 2, reflecting mirror 3,
It has a configuration in which a condenser lens 4 and an optical semiconductor device detector 5 are incorporated into the same case.

In the above configuration, detection of the object to be detected is performed as follows. First, the laser beam 6 emitted from the He--Ne gas laser 1 is intensity-modulated by the acousto-optic modulator 2 and is separated into transmitted light 7 and diffracted light 8 . Of these, the transmitted light 7 is blocked by the wall of the slit 9 as a result of the optical axis adjustment by the reflecting mirror 3, and only the diffracted light 8 is emitted to the outside and is irradiated onto the light irradiation point 11 of the object to be detected 10. The light reflected and scattered at this light irradiation point 11 and a part 12 of the background light around the object to be detected 10 are transferred to a condensing lens 4 at a condensing point on the light receiving surface of the optical semiconductor device detector 5. The light is focused on 13. The semiconductor position detector 5 outputs the position of the focal point 13 as an electrical signal, and the arithmetic circuit 14 detects the electrical signal to calculate the position of the object 10 to be detected. The results are displayed on a display unit 15 such as a plotter or CRT. Note that in order to improve the S/N ratio between the reflected/scattered light 12 by the object to be detected 10, that is, the electrical signal due to the signal light and the noise due to the background light, signal detection in the arithmetic circuit 14 is performed by modulation by the acousto-optic modulator 2. It is done synchronously.

On the other hand, the detected object 1 has moved a predetermined distance on the optical axis of the diffracted light 8.
For 0', the light 1 reflected and scattered at the light irradiation point 11/
2' is focused on a focal point 13', and the position of the object 10' to be detected is determined in the same manner as described above.

As described above, in the conventional non-contact displacement detection device, a laser light source, an optical modulator 1 position detector such as an acousto-optic modulator, and their drive control circuit (for example, an acousto-optic modulator drive circuit 1) are used.
6) Since the power supply etc. are housed in one case, the shape and
As the weight increases, there is a problem in that the position detector and the condenser lens are affected by heat from the laser light source, resulting in detection errors. In particular, when increasing the output of the laser light source to expand the measurement range and ensuring that the detector 5 receives reflected and scattered light of the required intensity even when the object to be detected is located far away. This tendency is remarkable;
Movement becomes difficult and detection accuracy decreases.

[Summary of the invention]

The present invention was made in view of these circumstances, and its purpose is to provide a non-contact displacement sensor that enables expansion of the measurement range by increasing the output of the light source, and that also provides high detection accuracy with a small size, light weight, and low heat generation. The object of the present invention is to provide a detection device.

In order to achieve such an object, the present invention separates a laser light source into a detection light source and a visual light source, and makes the former compact and
The semiconductor laser is lightweight, has low heat generation, and can provide high output power, and the semiconductor laser and the part that irradiates light onto the object to be detected and detects reflected and scattered light are used as a second device, and a second device includes a visible laser light source for visual inspection. This is a device that has been separated from the device of No. 1. The visual light is guided to the first device through a light transmission line such as an optical fiber, but the detection light does not pass through such an optical transmission line, so even if the optical transmission line is subjected to vibrations, bending, etc. This does not mean that the intensity of the detection light varies. Hereinafter, the present invention will be explained in detail using Examples.

〔Example〕

FIG. 2 is a configuration diagram showing an embodiment of the present invention.

In the figure, the present device includes a first device 20, a second device 30 spatially separated from the first device 20, a square, and a quartz-based optical fiber (GI-50
) has 40.

In this case, the first device 20 is equipped with an H
e-No gas laser (wavelength 63.2.8mm, output 1
mW) 21, a condensing lens 22, and a semiconductor to be described later.

- The device 30 of the second option includes a semiconductor laser (wavelength 830 nm, output 5 mW) 3 that emits detection light.
1,=1 remating lenses 32, 33, wavelength 632.
A dichroic mirror 34 that transmits 90% or more of 8 mm light and reflects 90% or more of light in the 830 nm wavelength band, a lens 4 that condenses reflected/scattered light from the object 10 and part of the background light 12, and a one-dimensional Position detection PSD 281352
(Manufactured by Hamamatsu Photonics, effective light receiving area 34 x 2.5
m) includes an optical semiconductor device detector P consisting of:

In the above configuration, the light 24 emitted from the H.-No gas laser 21 is transmitted to the first device 2 by the condenser lens 22.
0 and the second device 30 and is coupled to one end of an optical fiber 40 for propagation. The light 35 emitted from the other end of the second device 30 is made into almost parallel light by the collimating lens 33, passes through the dichroic mirror 34, and is emitted to the outside. is irradiated.

On the other hand, the laser beam 36 modulated at a modulation frequency of 2 kHz and emitted from the semiconductor J-za 31 is transmitted to the cremeter lens 3.
2 makes it almost parallel light, and dichroic mirror 3
4, it is placed on the same optical axis as the laser beam 35 and similarly irradiates the light irradiation point 13 of the object to be detected. Then, the light reflected and scattered here and a portion 12 of the background light are focused by the condensing lens 4 onto a condensing point 13 on the light receiving surface of the optical semiconductor device detector 5, and the optical semiconductor device detector 5 Focus point 1 with
Outputs position 3 as an electrical signal. The arithmetic circuit 14 is
This electrical signal is detected in synchronization with the modulation of the semiconductor laser 31, and the position of the detected object 10 is calculated from the detection result and displayed on a display unit 15 such as a block or CRT.

Here, the reflected and scattered light of the modulated semiconductor laser light is
The light is collected as detection light and converted into an electrical signal, and then sent to the arithmetic circuit 14.
can be detected efficiently by On the other hand, He-No
Since gas laser light has low output and is not modulated, its reflected and scattered light is treated as noise like background light, and in that sense does not directly contribute to detecting the displacement of the object to be detected 10. The light irradiation point and measurement point on the object to be detected can be visually observed. That is, it is difficult to see the light irradiation point using only the semiconductor laser 31 due to the wavelength, but by using the He-Ne gas laser 21 for visual inspection, the measurement point can be easily confirmed. Also, since it is possible to know that the detection operation is in progress, danger can be prevented. Also,
H
The e-Ne gas laser 21 may be small and low output.
On the other hand, the semiconductor laser 31 is extremely small and lightweight, can provide high output, and generates almost no heat, so that a non-contact displacement detection device that has high output, is small, lightweight, and highly accurate can be obtained.

In particular, a He-Ne gas laser 21 is used as a second device 30 to irradiate light onto an object to be detected and detect reflected and scattered light.
By being separated from the first device 30 including the It is extremely easy to move, and the condenser lens 4 and semiconductor device detector 5 can be easily moved.
It is possible to virtually eliminate the occurrence of detection errors due to heat received from the sensor.

Here, the semiconductor laser 31 is provided on the second device side instead of the first device, and the detection light is irradiated onto the object to be detected without propagating through the optical fiber 4°. , vibrations applied to the optical fiber 40 itself.

Even if the intensity of the emitted light fluctuates depending on the song, etc., it is only the light for visual viewing, and the intensity of the detection light is always constant, so high detection accuracy can be obtained.

In addition, when modulating laser light to improve detection accuracy, conventional He-No gas lasers use an acousto-optic modulator, but in general, acousto-optic modulators are not affected by the effects of vibration or heat. There was a problem that the detection accuracy deteriorated due to the change in the diffraction angle and the fluctuation of the measurement point. On the other hand, since semiconductor lasers can be easily directly modulated, there is no need for an acousto-optic modulator and its driving circuit, which solves the above-mentioned problems, and also allows for a reduction in size and weight.

In this embodiment, the dichroic mirror 34 was used as a means for placing two laser beams on the same optical axis, but the present invention is not limited to this, and a half mirror,
A beam splitter or any other device that can place two laser beams on the same optical axis may be used. However, for efficient synthesis, a dichroic mirror is preferred because of its wavelength selectivity and low energy loss.

Further, in this embodiment, a semiconductor laser with a wavelength of 830 nm was used in view of the spectral sensitivity characteristics of the optical semiconductor device detector 5, but the wavelength is not limited to 780 nm.
It may be selected as appropriate depending on the sensitivity of the position detector, such as nm. Note that the above position detector is not limited to PSD, but also CC.
D-? Any device that can detect the position of the irradiated light, such as a MOS image sensor, will suffice.

Although the method for detecting the displacement of the object on the laser optical axis as the displacement of the irradiation point on the optical semiconductor device detector of reflected/scattered light has been described above, the present invention is not limited to this. However, as long as the object to be detected is irradiated with a laser beam and the reflected and scattered light is detected to detect the displacement of the object, other methods such as the focal point method can be used as well. Applicable.

〔Effect of the invention〕

As explained above, according to the present invention, the light source is separated into one for detection and one for visual observation, with the former being a semiconductor laser and the latter being a He-
In addition to using a Ne gas laser, the semiconductor laser and the part that irradiates the object to be detected and detects reflected and scattered light are separated from the first device that includes a visible laser light source for visual inspection as a second device. Despite increasing the output due to the expansion of the measurement range, the laser is small and easy to move, generates little heat, has high detection accuracy, and allows easy visual confirmation of the measurement point. A non-contact displacement detection device can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional non-contact displacement detector, and FIG. 2 is a block diagram showing an embodiment of the present invention. 4.22.i...Condensing lens, 5...Semiconductor device detector, 10...Detected object, 11...Light irradiation point,
12... Reflected/scattered light, 13... Focus point, 14
...Arithmetic circuit, 20...First device, 21...
...He-N for visual inspection. Gas laser, 23...Semiconductor laser modulation drive circuit, 30...Second device, 31...Semiconductor laser, 32.33...Collimating lens, 34...
・Dichroic mirror, 40th grade...Optical fiber. Patent applicant: Yasutani Glass Co., Ltd. Agent: Masaki Yamakawa (TL or 2 people) Release of drawings - (No change in content) Figure 1 Figure 2 Procedural amendment (to the Commissioner of the Japan Patent Office) 59.9. -5 1. Indication of the case 1939 Patent Application No. 10'1323 21b Name of the founder - Hiroyuki Nonoumura (n sheet ratio device 3, person making the amendment Relationship with the case Patent applicant name ( Name) Hoya Glass Co., Ltd. Subject of 6th Amendment (In Specification) c-, Nba Light!"""a, J Procedural Amendment (Sponsored) 1. Indication of the Case 1980 Patent Application No. 109323 2 , Name of the invention Non-contact displacement detection device 3, Relationship with the case of the person making the amendment Patent Name of applicant (Name) Hoya Co., Ltd. (fl) Amend the scope of claims in the specification in an attached document. (2) "Semiconductor device detector" on page 3, line 6 of the specification is replaced with "
"Optical semiconductor device detector". (3) In the same book, page 5, line 5, replace [-1st] with “72nd”
and correct it. (4) "Climeter" on page 6, line 20 of the same book is corrected to "collimate." (5) Correct "light irradiation point 13" in lines 3 and 4 of page 7 of the same book to "light irradiation point 11". (6) "Induction" in page 8, line 17 of the same book is amended to "induction". (7) "Semiconductor device detector" in line 20 of the same page of the same book is corrected to "optical semiconductor device detector." (8) In the first line of page 9 of the same book, ``kara-netsu wo'' is corrected to ``kara-no-netsu wo''. (9) Correct "takata" in line 19 of the same page of the same book to "kogata". (101 “Non-contact displacement detector” in the same book, page 11, line 18)
is corrected as a "non-contact displacement detection device". α1) "Semiconductor device detector" in line 20 of the same page to line 1 of page 12 of the same Ministry is corrected to "optical semiconductor device detector." (12) Correct the passage of Figure 2 on a separate sheet. The attached document ``A first device equipped with a laser that emits visible light for visual viewing, a second device spatially separated from this, and an optical transmission line that guides the visible visible light for visual viewing to the second device. The second device includes a semiconductor laser that emits detection light, a semiconductor laser that emits light for detection, and a second device that places the moonlight of this semiconductor laser and visible light guided by the optical transmission path on the same optical axis to be detected. A non-contact displacement detector device characterized by comprising means for irradiating light onto an object and detection means for detecting light reflected and scattered by the object to be detected.''

Claims (1)

[Claims] a first device comprising a laser that emits visible light for visual viewing;
It is equipped with a second device spatially separated from this, and an optical transmission line that guides the visible light for visual viewing to the second device, and the second device includes a semiconductor laser that emits detection light and a semiconductor means for irradiating the output light of the laser and the visual visible light guided by the optical transmission path onto the detected object on the same optical axis;
1. A non-contact displacement measuring device comprising a detection means for detecting light reflected and scattered by an object to be detected.