JPS595911A - Device for measuring distance and angle - Google Patents

Abstract

PURPOSE:To decrease cost in the manufacture, by simultaneously measuring the distance to a surface to be measured and the angle formed by the surface based on a deflection angle, when light from one light source passes a light deflecting means and is reflected by the surface to be measured, and outputs are generated from two light detectors. CONSTITUTION:An optical waveguide layer 32 is formed on a single crystal substrate 31 having an electrooptic effect. A light deflecting means is constituted by providing a crossed finger electrode 33 on the optical waveguide layer 32. Light from a semiconductor laser 30 is inputted to one end of the waveguide layer 32 and outputted from the other end. The light is inputted to the surface to be measured 34. Light detectors 35 and 36 are arranged at the output end surface. An electric field from a high frequency power source 39, whose frequency can be changed, is made to be applied to the electrode 33. Elastic surface waves are generated on the layer 32 in this way, and the transmitted light is deflected. The deflection angle is changed by changing the frequency of the power source, and the angle is detected by the detectors 35 and 36. The distance from the laser 30 to the surface 34 and the angle formed by the layer 32 and the surface 34 can be obtained by computation.

Description

Detailed Description of the Invention (Field of the Invention) The present invention is capable of determining the distance to a surface to be measured and the angle formed by the surface by comprising means for deflecting light from a light source and two light detection means. This invention relates to a distance/angle measuring device that can measure simultaneously.

(Background of the Invention) Conventionally, the first method of simultaneously measuring the distance from a reference point etc. to a certain surface and the angle formed between the reference surface etc. and that surface is
There was a method as shown in the figure. As shown in the figure, in this method, two laser light sources 11 and 12 emit light rays 11' and 12' toward a measurement target surface 13, and the light rays 11'' and 12' are reflected by the measurement target surface 13. " is received by the photodetector array 14 arranged on the reference plane 15.

In this case, the distance and angle between the measurement target surface 13 and the reference surface can be measured from the positions of two pixels that produce light output among each pixel of the photodetector array 14.

However, the conventional type requires two laser devices and an array of photodetectors, which has the disadvantage of increasing the price of the measuring device.

(Object of the Invention) The object of the present invention is to ``in view of the problems of the conventional type described above, in a distance/angle measuring device, light from a single light source is incident on a surface to be measured via a deflecting means, and measurement is performed. The object of the present invention is to provide a low-cost and highly accurate distance/angle measuring device based on the concept of detecting reflected light from a target surface using two photodetectors.

(Structure of the Invention) The present invention includes one light source, a means for deflecting light from the light source, and two photodetectors, and the light emitted from the light source through the light deflecting means is detected as an object to be measured. Simultaneous measurement of the distance from the deflection angle of the light in the two light deflecting means to the measurement target surface and the angle formed by the measurement target surface with respect to the reference plane when the light is reflected by the surface and generates optical output to the two photodetectors. It is characterized by

(Effects of the Invention) According to the present invention, by using one light source, a variable deflection means for deflecting light from the light source, and two photodetectors, it is possible to determine the distance from a predetermined position to a surface to be measured. It becomes possible to simultaneously measure the angle formed by a predetermined surface or line and the surface to be measured, and it is possible to realize a device with lower cost and higher accuracy than conventional types.

(Explanation of Examples) The present invention will be described in detail below using the drawings.

FIG. 2 is a graph showing the principle of distance and angle measurement in the measuring device of the present invention. In Figure 2, light source 2
0 as the origin, and the photodetectors 21 and 22 are placed at two points on the X axis (
Xl, 0), (X2.O).

The position where the surface to be measured intersects with the y-axis is (o, d), and the angle it makes with the X-axis is ψ. When the light from the light source is reflected by the surface to be measured and produces a light output to the photodetector 21, the angle that the light from the light source makes with the X axis is 01, and the angle of incidence on the surface to be measured is α. . The equation expressing the reflective surface is y=d+xtanψ-(1), and the light from the light source is y=x theory θ1...(2
) is given by The coordinates of the light incident point 23 on the surface to be measured are given by (1) and (2). Also, since the incident angle is α = 90° - (θ1 - ψ) (4), the angle φ that the reflected light from the reflective surface makes with the X axis is φ - 90° - (α + ψ) - 2ψ−θ, ...(5)
becomes. Therefore, the reflected light is expressed as (3L from (5)), and since this X thin section is (Xl, 0), (6
). Similarly, when the light output from the light source forms an angle θ2 with the X axis, the optical output appears on the photodetector 22. Therefore, since Xl and X2 are known, θ1. If θ2 is known, d and ψ can be found from (7) and (8).

FIG. 3 shows a distance/angle measuring device according to an embodiment of the present invention using the above-described principle. In the device shown in the figure, an optical waveguide layer 32 is formed on a semiconductor laser 30 as a light source and a single crystal substrate 31 having an electro-optic effect such as niobium oxide (LiNb05) as an optical deflection means. A device is provided on which cross-sliding electrodes (5) (IDT) 33 are formed. Also,
Two silicon photodiodes 35 and 36 as photodetectors are arranged at a predetermined interval on the light output side end face of the electric light deflection means. The measuring device shown in FIG.
It is equipped with a processing circuit 37, a display 38, and a high frequency power source 39 whose frequency can be varied.

In the apparatus shown in FIG. 3, light from a semiconductor laser 30 enters from one end face of an optical waveguide 32 on an electro-optic crystal substrate 31, passes through the optical waveguide layer 32, and exits from the other end face, and is directed to the surface to be measured. 34. In this case, a high frequency electric field is applied to the interdigital electrodes 33 on the optical waveguide layer 32 from a high frequency power source 39, and a surface acoustic wave (SAW) is generated on the optical waveguide layer 32. The light transmitted through the optical waveguide layer 32 interacts with the surface acoustic wave, is deflected, and exits from the other end face of the optical waveguide layer 32 . The light reflected by the measurement target surface 34 is detected by a photodiode 35 or 36. Furthermore, the deflection angle of the light from the semiconductor laser 30 is determined by the interdigital electrode 3.
Since the frequency (6) of the high frequency voltage applied to the photodiodes 35 and 36 can be varied depending on the wave number, the deflection angle of the light can be determined from the frequency at which the output is generated in the photodiodes 35 and 36, respectively. Therefore, distance d and angle ψ can be calculated using equations (7) and (8).

In reality, as shown in FIG. 3, the processing circuit 37 changes the frequency of the high frequency power supply 39 and monitors the output from each photodiode 35 and 36. diode 3
5 and 36 can be known, and based on this information, the processing circuit 37 performs arithmetic processing to calculate the distance and angle, and the calculation results are displayed on the display 38.

FIG. 4 shows the configuration of a distance/angle measuring device according to another embodiment of the present invention. The device in the figure uses, for example, a helium neon (He-Ne) laser 40 as a light source,
A galvanometer mirror 41 is used as a light deflection means. In the figure, 43 and 44 are photodiodes, 45 is a processing circuit, and 46 is a display.

In the apparatus shown in FIG. 4, light from a light source 40 is deflected by a gal-guffin-41, reflected by a surface to be measured 42, and then detected by a photodiode 43 or 44. The galvanometer mirror 41 is driven and controlled by an electric signal from a processing circuit 42, and the output from each photodiode 43 and 44 is input to a processing circuit 45. The processing circuit 45 can determine the deflection angle of the light from the magnitude of the electric signal that drives the gal/guhumin=41, and the deflection angle when the output from each photodiode 43 and 44 is generated determines the above (
Similarly, using equations 7) and (8), distance d and angle ψ
is calculated and the calculation result is displayed on the display 45.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a conventional distance/angle measuring device, FIG. 2 is a graph for explaining the present invention in detail, and FIGS. 3 and 4 are distance/angle measuring devices according to embodiments of the present invention. It is a schematic diagram showing an angle measuring device. 11.12, 30.40...Laser light source, 13°34.
42... Measurement target surface, 14... Photodetector array, 3
1... Electro-optic crystal substrate, 32... Optical waveguide layer, 3
3... Interdigital electrode, 35, 36, 43. 44... Photodiode, 37, 45... Processing circuit, 38°4
6...Display, 39...High frequency power supply, 41.
...Galvano mirror 6 Patent applicant Tateishi Electric Co., Ltd. Agent Patent attorney Tatsuo Ito 〃 Tetsuya Ito (9)

Claims (1)

[Claims] a light source and means for deflecting light from the light source; 2.
When the light emitted from the light source through the light deflection means is reflected on the measurement target surface and generates light output to the two photodetectors, the light in the two light deflection means is A distance/angle measuring device characterized by simultaneously measuring the distance from a deflection angle to a surface to be measured and the angle formed by the surface to be measured with respect to a reference surface.