JPS581125A - Spatial filter device - Google Patents

Abstract

PURPOSE:To permit a differential spatial filter device of simple structure, which measures a velocity, etc., by using the optical irregularity of a body to be measured, to perform stable velocity measurement without any restriction even under strong electromagnetic induction, in a liquid, and in an explosive atmosphere, by arraying the photodetection ends of optical fibers in a line, and leading alternate optical fibers to two photodetectors. CONSTITUTION:The photodetection ends 14 of optical fibers 19 are arrayed in a line and alternate fibers are put together as a fiber bundle 16 and a fiber bundle 17. Incident light from a moving body is guided from alternate photodetection ends 14 through the fiber bundles 16 and 17 and added together by a photodetector, respectively. Therefore, this spatial filter device is utilized for the measurement of the velocity of the moving body, etc. Since this filter device has the simple and durable constitution and also handles light signals, so there is no influence of electromagnetically induced noise and the stable velocity measurement is carried out even under strong electromagnetic induction, in a liquid, and in an explosive atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION In the present invention, there is a differential method that uses optical unevenness of the object to be measured to measure occlusions, etc.! This is a spatial filter device K11l.

A conventional spatial filter device 1 includes a comb-shaped light receiving element 11 as shown in 11111! It is configured using Fi.

When the optical system connects the tII of the light reflected or transmitted from the moving object to the light-receiving surface of the first group of light-receiving elements, the optical unevenness of the moving object becomes Only a certain special electric spatial frequency is selected from among the distributions (referred to as mold), and the output terminal 2. Outputs the s and shi signals.

On the other hand, the negative spatial frequency component is canceled on the light receiving surface and is not output as a signal in response to the movement of the object.

Now, when the image with the spatial frequency selected here moves to one point on the light-receiving surface, the comb's l bi,
Output terminal 2 for 11 (light receiving element lO: main purpose)
．． Each of the redemption names that appear in 1 changes by one period. When these two outputs are differentially amplified, light source O fluctuations and S
It is possible to output a signal regardless of the noise caused by direct current fluctuations such as changes in visual brightness of the moving object.

#1llN21AK when measuring object 011
The 11-wave mold detection-6 configured as shown is a differential increaser 5aso
Detect the center frequency of the output signal (1/)
-As mentioned above, Ks11Il object 90@0 empty threshold filter device 4C) Output signal F118M for 1 bit, chi*11hK
Therefore, the #i proportional relationship is established in the center frequency O of the IIO moving chromatic power signal, and the velocity of the object 9 is V and the magnification of the optical system 80 is 1. Assuming that the pitch of the spatial filter is P and the frequency around the center of the output signal is f, then V knee Pf is obtained.

Since P and tumor are constants, the object O occlusion V can be determined by a simple multiplication of the center wrinkle fK using an arithmetic circuit.

Another type of spatial filter device is known, as shown in FIG. The light 18 from the moving object passes through the phase grating l
The light beams 11FK are separated in two directions by the light beam K, and are received by the lens 11 into two groups of light beams, ie, the O light detection -12.

This type of spatial filter also separates and adds the light from the SS object every other object in a comb-like manner, so like the light receiving element group mentioned above, there are two
Jail by differentially amplifying the light detection lit 20 outputs
! can be detected.

However, the spatial filter #tW/l using a group of light-receiving elements is under strong electromagnetic induction, such as a lifting platform near a large lid motor, where each output of the spatial filter device is affected by the multiplier output. It is difficult to determine the center frequency f in places where it is inconvenient to use electricity, such as inside liquids, explosive atmospheres, etc., where it is difficult to detect the center frequency f due to electromagnetic noise.

In addition, the spatial filling/device using a phase grating for light flux can alleviate the above problem by attaching an optical fiber to the photodetector position, but the phase grating, lens system, and optical fiber can alleviate the above problem. This has the disadvantage that the optical system that constitutes it is complicated.

The object of the present invention is to provide a spatial filter device that has a simple structure and is capable of stably collecting continuous f-tubes without any restrictions, even under strong electromagnetic induction, in liquids, and in explosive atmospheres. .

Hereinafter, embodiments of the present invention will be described starting from 1k with reference to the drawings. FIG. 4 is an external perspective view of one embodiment O, No. 611t
j is an exploded perspective view. As shown in these 0 diagrams, many O
Since the optical fibers 1- are sandwiched by the guides Pli20, 21OVIII, the light receiving ends of each optical fiber 19 are aligned in a line. And optical fiber 19t
Every other fiber bundle 16 and optical fibers 17 and 17 are put together, and these fibers 1g and 170 end lI are guided to a photodetector WI1g. Specific Kul-i P-101!1
When the optical 7 filter 1 @ t is sandwiched in the spatial filter device constructed in this way and the friend 28 is incident on it from a moving object as shown in No. 611, the incident: tUkatsugaku 1) $P of the fiber light receiving end 14 is guided by the fiber bundle 111.17 and added by the photodetector 18. Therefore, 111wJ and Nan8en no Sora 87
4 router device and Oka Is, and can be used for moving objects O compliance needle column, etc. , Guy r plate 20.21 semicircular Oe! By arranging the optical 7-eye receiving ends 14 along J*, the optical 7-eye receiving ends 14 are arranged in an arc shape.〇This spatial filter device @28Ujll! Since the receiving end of the fiK optical fiber can be disposed around the shaft 26 of the motor 24 as shown in FIG. 8, it is suitable for scooping the speed f of an O-rotating body such as the shaft 26. As shown in FIG. 6, since the light reaches the fiber bundle 16, 17 and is guided at a distance of <Km, the photodetector 18 can be placed at a distance from the motor 24 as well. The output of this photodetector 18 is differentially amplified by a differential amplifier 22 and frequency detection e! The output signal 40 is sent to x21, and the center circumference number is detected, converted to rotational speed by the arithmetic processing circuit 28), and sent to the motor control circuit (not shown).As shown in FIG. Electromagnetic noise from
Even if 2 occurs, if the electrical signal system after the photodetector 18 is kept far away, there will be no ionization noise 82Fi optical filter, so electromagnetic noise 82
It is possible to perform rotational uniformity steel legs without being affected at all.

According to the present invention, as explained in the above 9 cases,
Spatial filter Ii* can be realized with an extremely simple and simple configuration, and since this spatial filter device handles optical signals rather than electrical signals, it is not affected by electrical conduction noise, and it is not affected by electromagnetic noise. Even in medium and explosive atmospheres, it is possible to perform stable retaliation and vertical rotation.

ζ SUO Simple & Explanation The 1st ml is a conventional example of 1,000ml, and the 2nd figure is a 7-port 11-liter speedometer using a conventional optical filter.

Fig. I18 is a perspective view of a conventional example of operation, jlI4 is a perspective view of the present invention 〇-implemented feeding outside m, Kamesuzusha Doi 1/1A
An exploded perspective view of f4, the tortoise diagram is a professional diagram for explaining the nine-sea plan using the Oka real layer side, Figure 97 is an external perspective view of the other O example, and the 8th hook is the 7th hook. The example shown in the figure shows a 7-hole system that uses a tube with a constant degree of transfer.

This is a diagram.

1... Light receiving element, 4.26... Spatial filter device,
9... Moving object, 10... Phase grating, 12
．． 18...Photodetector, 14...Optical fiber light receiving end, 16...*m.

16.17...Fiber bundle, 19...Optical fiber, 20, 21-...Guy +7.1m.

Applicant: Tateishi Electric Co., Ltd. Note 5 (branch) Should be back 3 )$-7th 'IP9 self No ν

Claims (1)

[Scope of Claims] (I) A spatial filter device that receives light from a plurality of optical fibers arranged in a row and has a structure in which every other fiber is guided to two photodetectors. 2. A spatial filter device according to claim 1, characterized in that seven optical eyers are aligned by sandwiching a plurality of optical fibers between two I-id plates.
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