JPH0210205A - Sensor head device - Google Patents

Abstract

PURPOSE:To improve the measuring accuracy by providing at least one of a light source and a photodetector outside a sensor head and transmitting at least one of an emitted light and a received image by an optical fiber. CONSTITUTION:A controller 1 and a sensor head 6 are connected each other by an optical fiber 4 and a bundle optical fiber 5. The controller 1 is provided with a semiconductor laser 2 as a light source and a photodetector 3. The light emitted from the laser 2 is sent to the head 6 via the optical fiber 4. Then, the light is projected out of the head 6 through a microlens array 7. This projected light is, after it is condensed by each microlens, dispersed and accordingly diffracted. Therefore, many spots are formed far at a distant place by the diffracted light. The projected light from the head 6 is radiated to an object 15 to be detected, and the reflected light is received by the photodetector 3 through the objective lens in the head 6 and the optical fiber 5. Thus, if the coordinates of the position on the element 3 are detected, the position coordinates of the object 15 can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention At least one of a light source and a light receiving element is provided outside a sensor head, and at least one of emitted light and a received light image is transmitted through an optical fiber. This makes it possible to reduce the influence of electrical noise and changes in element characteristics due to the environment.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor head device having a light projecting section and a light receiving section, and particularly for three-dimensional shape recognition.

Prior Art and Its Problems A conventional sensor head for three-dimensional shape recognition consists of a light source, a projection optical system for projecting light from the light source onto an object to be detected, and a condenser that combines the reflected light from the object to be detected. It is equipped with a light-receiving optical system for generating an image, and a light-receiving element that outputs a signal corresponding to the formed light-receiving image.

In such conventional sensor heads, a light receiving element is provided within the sensor head.

There has been a problem in that the light receiving element is adversely affected by static electricity, electric fields, etc. that exist around the sensor head, resulting in a decrease in measurement accuracy. Furthermore, since the light source and the light receiving element are easily affected by external environments such as temperature and humidity, measurement accuracy will decrease due to changes in the environment surrounding the sensor head.

Additionally, there is a light source and light projection optical system inside the sensor head.

Since a light-receiving optical system and a light-receiving element are provided, there is a problem in that the sensor head becomes larger.

SUMMARY OF THE INVENTION Purpose of the Invention The present invention provides a sensor that is not significantly affected by electrical noise or environmental conditions, has relatively high measurement accuracy, and is equipped with a small and lightweight sensor head.
The purpose is to provide a head device.

(1) Achievements and Effects of the Invention A sensor head device according to the present invention is a sensor head having a light projecting section and a light receiving section, in which at least one of a light source and a light receiving element is provided outside the sensor head, At least one of the emitted light and the light-receiving image between at least one of a light source and a light-receiving element provided outside the sensor head and at least one of the corresponding light-emitting part and light-receiving part of the sensor head. It is characterized in that transmission is performed using an optical fiber.

According to this invention, at least one of the light source and the light receiving element is provided outside the sensor head,
An optical fiber is used to transmit either the projected light or the received light image between an externally provided element and the sensor head. Therefore, at least one of the light source and light-receiving element installed outside the sensor head is affected by electrical noise near the sensor head (static electricity, electromagnetic field, etc.) and environmental changes such as temperature and humidity surrounding the sensor head. You can prevent this from happening. Furthermore, since the number of parts provided in the sensor head can be reduced, the sensor head can be made smaller and lighter.

DESCRIPTION OF EMBODIMENTS FIG. 1 is a diagram showing the configuration of a sensor head device according to the present invention. Sensor head device.

It is composed of a controller 1 and a sensor head 6 that perform light emission control, light reception control, light reception signal processing, etc. The controller 1 and the sensor head 6 are connected by an optical fiber 4 and a bundle optical fiber 5. The controller 1 is provided with a semiconductor laser 2 and a light receiving element 3 as a light source. The light receiving element 3 is, for example, a CCD (Charge Coupled Device).
e) and PSD for two-dimensional measurement with electrodes on the four sides (Po
sttlon 5 sensitive Devlce) is used.

Emitted light from the semiconductor laser 2 is introduced into the optical fiber 4 from its end face. The light receiving element 3 is arranged at a position to receive the light emitted from the bundle optical fiber 5.

FIG. 2 is a partially cutaway perspective view of the sensor head 6. As shown in FIG. The sensor head 6 is housed in a box 12. At the front of this box 12, at a certain distance in the horizontal direction,
A window 8 for projecting light and a window 9 for receiving light are formed. window 8
The tip of an optical fiber 4 for transmitting projection light is fixed to. A micro-lens array 7 is attached to the tip end surface (light exit surface) of the optical fiber 4, which condenses the emitted light and forms a light spot by diffracted light at a distance. A micro-lens array is constructed by arranging a large number of micro-lenses (eg, micro-fisted Fresnel lenses) on one substrate.

The window 9 is provided with an objective lens lO. Behind the objective lens 9, a bundle optical fiber 5 for image transmission is arranged with its end face (light receiving surface) 11 facing the objective lens. The bundle optical fiber 5 is constructed by bundling a large number of optical fibers.

The emitted light from the semiconductor laser 2 enters the optical fiber 4, propagates within the optical fiber 4, and is sent to the sensor head 6.

The light emitted from the tip surface of the optical fiber 4 passes through the micro lens array 7 and is emitted from the sensor head 6. This emitted light is focused by each microlens and then diffused, causing diffraction, and a large number of spots of diffracted light are formed in the distance h''.

The diffraction angle θ1 of the projected light from the sensor head 6 is expressed by the following equation.

θ −5in−′ (nλ/A) ・(
1) Here, n is 0 and a positive or negative integer (n=0°±1
．． ±2. ), λ is the wavelength of light, and Δ is the distance between adjacent micro lenses in the micro lens array 7.

The projected light from the sensor head 6 is irradiated onto an object to be detected 15 located in front of the sensor head 6. The irradiated light is reflected by the object to be detected 15, forms an image on the light-receiving surface 11 of the bundle optical fiber 5, and enters the light-receiving surface 11 of the bundle optical fiber 5 via the objective lens 10 provided in the sensor head 6. This incident light propagates within the bundle optical fiber 5 for image transmission, exits from the other surface, and is received by the light receiving cable 3.

Next, the principle of shape recognition of the detected object 15 will be explained with reference to FIGS. 3 and 4. FIG. 3 shows the measuring system viewed from above, and FIG. 4 shows the measuring system viewed from perspective. Box 12 is not shown.

The optical axis of the light emitted from the optical fiber 4 and the optical axis of the objective lens IO are parallel, and the distance between these optical axes is d.

The optical axis of the objective lens lO is set as the Z axis, and its origin is set at the center of the objective lens lO. Consider the X and Y axes in a plane perpendicular to the Z axis. The Y-axis is taken in the direction that connects the optical axis of the light emitted from the optical fiber 4 and the optical axis of the objective lens lO. It is assumed that the deflection angle of the projected light is θ, and the angle at which the anti-11·J light from the object 15 intersects with the optical axis of the objective lens IO is θ2. Objective lens 1
0 and the light receiving surface 11 of the optical fiber 5.

The coordinate system of the light spot position of the diffracted light on the object 15 to be detected is (
x + y, z), and the positional coordinates of the imaging point of the reflected light on the light-receiving surface 1■ are (x, yt).

The spot position coordinates of the diffracted light on the detected object 151- (
x + yt Z) is the detection position (x
, y1) can be obtained as follows.

First, from the geometrical properties of the optical system (X+y).

Do not consider the sign of X1+ yl, consider the absolute value) x
−(xt/jj)z
...(2) y= (yt /jri z
...(3) Z −d / (janθ
+ tanθ2) −(4)■.

The angle θ1 in equation (4) is given by equation (1), and the angle θ
2 is.

θ2− tan (y, /jri
- given by (5).

Position coordinates (x
, y1) correspond to the positional coordinates on the light-receiving element 3, so by detecting the positional coordinates on the light-receiving element 3, the positional coordinates (X) on the detected object 15.

y, z) can be found.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a sensor head device. Figure 2 is a partially cutaway perspective view showing the sensor head taken out and enlarged from the sensor head device shown in Figure 1;
3 and 4 illustrate the principle of shape recognition, with FIG. 3 being a plan view and FIG. 4 being a perspective view. 1... Controller, 2... Semiconductor laser. 3... Light receiving element, 4... Optical fiber 5...
・Bundle optical fiber. 6...Sensor head. 7...Microshains φ array. 11... Light receiving surface. Patent applicant Tateishi Electric Co., Ltd. Representative Patent attorney Kenji Ushiku (1 other person)

Claims (1)

[Claims] In a sensor head having a light emitting part and a light receiving part, at least one of the light source and the light receiving element is provided outside the sensor head, and at least one of the light source and the light receiving element provided outside the sensor head is provided. On the other hand,
A sensor head device characterized in that at least one of an emitted light and a received light image is transmitted between at least one of a light projecting section and a light receiving section of the corresponding sensor head using an optical fiber.