JPS6235211A - Laser scanning type outer diameter measuring instrument - Google Patents

Abstract

PURPOSE:To miniaturize a measuring instrument by receiving the outgoing beam from the semiconductor laser having a polarization function through a collimating lens and condenser lens and by detecting the outer diameter of the measuring body inside the parallel beam moving zone between the collimating lens and condenser lens. CONSTITUTION:The outgoing beam from the semiconductor laser having the function to deflect the outgoing beam, namely from a beam scanning laser (BSL) 20 is made the parallel pencil of beams by a collimating lens 3, condensed by a condenser lens 10 and made incident on a beam detector 11. The parallel pencil of beams between the lens 3, 10 moves in parallel in the arrow mark direction Y and the beam after passing through the lens 10 moves in the arrow mark direction Z, when the outgoing beam of the BSL 20 is controlled with deflection in the arrow mark direction X. Therefore by measuring the beam shielding time by the measuring body 12 with the measuring system of the beam detector 11, etc. by placing the measuring body 12 of a fiber, etc., for instance, inside the parallel pencil of beams moving zone between the lens 3 and lens 10, the outer diameter thereof can be measured. The miniaturization of the outer diameter measuring instrument is thus enabled.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to a laser scanning method for measuring the outer diameter of an object to be measured, such as an optical fiber, TA, cable, etc., by laser scanning. Concerning outside diameter measuring instruments.

In particular, it relates to means for simplifying the device structure.

[Conventional technology]

Laser scanning outer diameter measuring instruments can quickly and accurately measure outer diameter dimensions in a non-contact manner, so they have been introduced into production processes and inspection processes in an extremely wide range of industrial fields, and are greatly contributing to process automation. Contributing.

The measurement principle of a laser scanning outer diameter measuring device is to place the object to be measured in a laser beam that repeatedly scans at a constant speed, and use a receiver to detect the length of the shadow created by the object. This is what we do.

FIG. 9 is a diagram showing the configuration of a conventional laser scanning type outer diameter measuring instrument. The laser beam emitted from laser I is mirror 2a
It passes through r 2 b and collimating lens 3 and enters polygon mirror 4 . The polygon mirror 4 is connected to a motor 7 driven by a motor driver 6 responsive to the output signal of an oscillator 5. The reflected light from the polygon mirror 4 is collimated by the collimating lens 3, passes through the first window 8 and the second window 9, is condensed by the condensing lens 10, and enters the photodetector 11. do. At this time, a part of the parallel beam is blocked by the measuring object I2 placed in the parallel beam moving area between the first and second windows 8 and 9, so an edge portion is generated in the output signal of the photodetector 11. .

This edge portion is detected by an edge detector 13. An f-) signal based on this edge detection signal is generated by the dart circuit 14 and applied to the counter 15. Counter z5 detects oscillator 5 during the period corresponding to its dart time.
The pulse train arriving from the pulse train is counted and supplied to the digital display Z6. In this way, the outer diameter of the object Z2 is displayed and measured.

[Problem that the invention seeks to solve]

However, the conventional laser scanning outer diameter measuring device described above requires an extremely high-precision optical IJ mirror 4, resulting in a complicated configuration and high cost. Since the driver 6 and the like are required, there is a problem that the device is extremely large and heavy.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a laser scanning type outer diameter measuring instrument that is simple in structure, can be manufactured at low cost, and is small and lightweight.

[Means for solving problems]

In order to solve the above problems and achieve the objects, the present invention is characterized by taking the following measures. That is, a semiconductor laser having a function of deflecting emitted light is provided, a collimating lens is provided so as to convert the emitted light from the semiconductor laser into a parallel beam, and the collimating lens condenses the parallel beam. A lens is provided, and a detection means is configured to receive the light condensed by the condenser lens and detect information on the outer diameter of the object placed in the parallel beam movement area between the collimating lens and the condenser lens. establish.

[Effect]

Since a semiconductor laser having the function of deflecting the emitted light is used as a light source, it is possible to measure the outer diameter without using a mechanical rotary deflection mechanism such as a polygon mirror.

〔Example〕

FIG. 1 is a diagram showing the overall configuration of a first embodiment ν of the present invention. In FIG. 1, 20 is a semiconductor laser that has the function of deflecting emitted light, that is, a beam scanning laser (
(hereinafter abbreviated as BSL). The light emitted from this BSL 20 is converted into a parallel beam by the collimating lens 3,
The light is condensed by the condenser lens 10 and enters the photodetector z1. When the emitted light from the BSL 20 is deflected and controlled in the direction of the arrow X, the parallel light beam between the lenses 3 and 10 moves in parallel in the direction of the arrow Y, and the light after passing through the condenser lens 10 moves in the direction of the arrow 2. Therefore, collimating lens 3 and condensing lens 1
For example, a fiber,
Place the measurement object I2 such as an electric wire or cable, and
By measuring the light blocking time due to No. 2 using a measurement system below the photodetector, its outer diameter can be measured. However, it is necessary to control the beam scanning speed of the BSL 20 so that the parallel light beam moves at a constant speed. Therefore, the BSL 20 will be explained below.

Semiconductor lasers are generally divided into two types depending on their waveguide mechanism: index-guided type and gain-guided type. The former is
The semiconductor laser has a mechanism in which light is guided by the refractive index in both the perpendicular and parallel directions to the junction surface of the active layer, whereas the ridge waveguide depends on the carrier density injected into the active layer. This mechanism is based on the property that light is guided along areas where the gain is high.

The BSL 20 actively utilizes this gain waveguide mechanism. That is, the gain distribution in the active layer of a typical gain waveguide semiconductor laser is symmetrical with respect to the center of the active layer because the current injection electrode is uniformly formed on the active layer. On the other hand, in the case of BSL 20, 2
Since divided electrodes are formed and current can be independently injected into this pair of electrodes, the gain distribution in the active layer can be made asymmetric.

Figure 2 is a perspective view showing an example of the structure of BSL 20.
Lett 33(8), 702.1978J.

As shown in FIG. 2, an n-type G
a 0.5 AtO, 5As cladding layer 22, p-type Ga
O,95AL O,05Am active layer 23, p-type GaO
, 5A/=0.5As 5 Rad layer 24 and n-type GaAs
Two electrodes 27h and 27b are provided.

In other words, these electrodes 27a and 27b are connected to the electrode divided portion 2.
8, a pair of IJ-do wires 29*,
The currents 11+1 . can be injected. Further, the electrode 27* of the casso layer 25
, 27b are each provided with a Zn diffusion region 30h.

A reed 30b is provided to limit the current excitation region injected from the electrodes 27a and 27b.

The asymmetric gain distribution in the active region 3 of the active layer 237 is achieved by changing the ratio of the injection current factor 1112 described above.

That is, when the injection current is made asymmetric (Il-II-I2), the density of carriers injected into the active layer 23 becomes higher on the electrode side where the injection current is larger.

For example, in the case of r, )r, more carriers are injected from the electrode 27a side, and the gain in the active region 31 is higher on the Il side. Therefore, the peak of the gain distribution is biased toward the 271L side, as shown in FIG. 3 (,). On the contrary, If<
Il, the gain in the active region 31 is higher on the side 27b, and the peak of the gain distribution is biased toward the side 27b as shown in FIG.
The distribution shown in b) is shown. Figure 3 (a), (b
It can be seen that when the gain distribution shown in ) is formed, the wavefront phase of the optical mode of the active layer 23 becomes a tilted wavefront as shown in FIGS. 4(a) and 4(b). Indicates the direction parallel to the slope of the wavefront.

The direction of the laser emitted light has a peak in the direction in which the light within the active layer 23 is deflected by a predetermined angle.

This emitted light peak position is the peak position of the output light to the active layer 23.
The characteristics of the operation as a light source are as shown in FIG.
The point is that it can be continuously deflected as shown by the arrow by variable operation No. 2.

Therefore, as shown in FIG. 6(b), BSI, 20
By placing the output end face of i4 on the focal point of the lens (f is the focal length), the parallel light flux after passing through the lens 3 is deflected as shown by the arrow Y in response to the beam deflection operation of the laser beam as shown by the arrow X. It becomes possible to move in parallel.

First, by combining the BSL 20 and the collimating lens 3, the beam scanning operation of the BSL 20, which is a light source, is performed, and the parallel beam can be moved in parallel without using a mechanical rotary deflection mechanism such as a polyco-9 mirror. can be performed easily and accurately.

FIG. 7 is a diagram showing the main parts of a second embodiment of the present invention. The difference between this embodiment and the first embodiment is that a pair of deflection plates 41 whose deflection directions are aligned in the same direction are provided in the parallel beam movement region between the collimating lens 3 and the condenser lens 10.
．． This is the point where 42 was inserted. That is, the oscillation mode of the semiconductor laser is the TE mode, and the electric field oscillates in a direction parallel to the bonding surface, so the deflection directions of the deflection plates 41 and 42 are aligned with the bonding direction of the semiconductor laser, that is, the BSL 20.

According to the second embodiment configured in this way, the measurement object 1
Errors due to rotation of the deflection direction caused by reflection on the 20 surface can be removed. As a result, there is an advantage that the photodetection sensitivity can be increased.

FIG. 8 is a diagram showing the main parts of a third embodiment of the present invention. This embodiment differs from the first embodiment in that a two-dimensional array photodetector 43 capable of receiving and detecting a projected image of the measurement object I2 is used as a photodetector. That is, in this embodiment, the shadow caused by the object 12 to be measured is projected onto the two-dimensional array photodetector 43, and the outer diameter of the object 12 to be measured is directly measured from the length of the projected image. This is an example.

According to this third embodiment, there is an advantage that the configuration of the signal processing circuit of the measurement system is simplified.

Note that the present invention is not limited to the above embodiments.

For example, between the BSL 20 and the collimating lens 3,
A shaping prism or the like may be inserted to make the light emitted from the SL 20 into a perfect circle. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, since a semiconductor laser having the function of deflecting the emitted light is used as a light source, it is possible to measure the outer diameter without using a mechanical rotary deflection device such as a polygon mirror. Become. As a result, it is possible to provide a laser scanning type outer diameter measuring instrument that has a simple configuration, can be manufactured at low cost, and is small in size.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall structure of the first embodiment of the present invention;
Figure 2 is a perspective view showing the BSL of the same embodiment, Figure 3 (a)
, (b) to Figure 5 (a) and (b) are the same BSL
Figures 6(a) and (b) show the characteristics of the same BS.
FIG. 7 is a diagram showing the main part of the second embodiment of the present invention, and FIG. 8 is a diagram showing the main part of the third embodiment of the invention. FIG. 9 is a diagram showing the configuration of a conventional example. 3... Collimating lens, 10... Condensing lens, I
I... Photodetector, 20... BSL (beam scanning laser). Patent Attorney Tsuboi Figure 1 Cause 2 (a) (b) Figure 3 Figure 4 Figure 6 Figure 8 Figure 9

Claims (3)

[Claims] (1) A semiconductor laser having a polarizing function for emitted light, a collimating lens provided to collimate the emitted light from the semiconductor laser, and a condenser that condenses the collimated light by the collimating lens. an optical lens; and a detection means for receiving the light condensed by the condensing lens and detecting information on the outer diameter of the object placed in a parallel beam movement area between the collimating lens and the condensing lens. A laser scanning type outer diameter measuring instrument characterized by: (2) The laser according to claim 1, wherein the parallel beam movement region between the collimating lens and the condensing lens is provided with a deflection plate that removes light having different polarization directions. Scanning type outer diameter measuring device. (3) The laser scanning type outer diameter measuring instrument according to claim 1, wherein the detection means is a two-dimensional array-shaped photodetector that receives a projected image of the object to be measured.