JPS6266110A - Optical distance detecting device - Google Patents

Abstract

PURPOSE:To exactly detect an image position by a plane-shape sensor which can easily be manufactured, by reflecting a beam from an object, which has passed through an observation lens, by a conical surface mirror, and detecting the image position by the plane-shaped sensor being vertical to an optical axis of a lens. CONSTITUTION:An image of a mark T which has been formed on an object O by irradiating an optical beam B is reflected by a cylindrical mirror, M, reflected by a conical mirror MC after passing through an observation lens L, and projected onto a plane-shaped image position detecting sensor P being vertical to an optical axis of the lens L. By detecting a position in the radial direction on the sensor P of the mark image, a distance extending from the lens L to the object is measured, and it becomes the same as a fact that the sensor P is positioned on an optimum image pickup surface PF. Since the mark T is shaped like a point, the mark image on the sensor does not become blurred irrespective of a distance to the object. Accordingly, an image position is exactly detected by the plane-shaped sensor P which is easily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical distance detection device that optically detects the distance to an object.

(Prior art) A marker on an object, which is generated by attaching a light emitter to the object or projecting a light beam, is projected onto an observation surface using an observation lens, and the image of the marker on the observation surface is Optical distance detection devices that detect the position and obtain distance information to an object are often used. An example of this type of optical distance detection device is shown in FIG. The illustrated device is RORS (R
iken Optical Range Sensing
This is a compact distance detection device based on a method called ``Method''.
This is an expanded version of the equivalent reference length in triangulation, making it extremely suitable for miniaturization. The operation of this mounting device will be briefly explained as follows. A light beam B is projected in the optical axis direction of the observation lens to generate a marker T on the object ○. The distance in the optical axis direction of the observation lens is detected by detecting the radial position of the marker image reflected by the cylindrical mirror M and projected onto the observation surface by the observation lens using the image position detection sensor P. This device is a fixed focus system, so
The disadvantage is that the sign image on the observation surface becomes blurred at a distance other than a certain distance.

For devices with a configuration in which the imaging position is uniquely determined relative to the distance, by matching the shape of the observation surface to a surface that satisfies the optimal imaging conditions, good markings can be achieved regardless of the distance to the target object. You will be able to obtain statues. FIG. 5 is a plan view of another conventional optical distance detection device, and this FIG. 5 shows an optimal imaging plane PF that satisfies the optimal imaging conditions. In the configurations shown in FIGS. 4 and 5, the optimal imaging plane is a conical surface, and especially in the detection device shown in FIG. 5, the optimal imaging plane PP- is given by the following equation.

Therefore, if the image position detection sensor is placed on this surface, the optimum imaging conditions should be satisfied.

(Problem to be Solved by the Invention) However, from the viewpoint of miniaturization and manufacturing of the distance sensor, it is not possible to form the image position detection sensor into a conical shape or arrange it on a conical surface or a polygonal pyramidal surface. It's not always easy, nor is it a good idea. Further, the optical sensor section is expected to be integrated with an amplification section, a calculation section, etc., and it is desirable that the optical sensor section be arranged in series as much as possible so that it can be used in common in several distance sensors. That is, from the viewpoint of manufacturing and serialization (versatility), it is preferable that the image position detection sensor be planar.

An object of the present invention is to provide an optical distance detection device that realizes a better imaging state while using a planarly arranged image position detection sensor in the distance sensor as described above.

(Means for solving the problem) The above purpose is to arrange a conical mirror Mc that reflects the light from the marker T that has passed through the observation lens L before it reaches the observation surface, as shown in Fig. 1. At the same time, the image position detection sensor P is placed on a plane perpendicular to the optical axis of the observation lens L using a conical mirror M.

This is achieved by placing it in the opposite direction.

Note that if the sign has a certain size, blurring may occur due to oblique incidence on the observation surface, and it is not necessarily possible to obtain an image with the least blurring on the optimal imaging surface as shown in equation (1) etc. . Therefore, normally, a conical mirror is placed at an angle intermediate between the angle that provides the optimum imaging condition and the plane.

Furthermore, the planar sensor or planar image position detection sensor in this specification includes both a sensor in which a plurality of sensors are arranged on a plane and a plate-like integrated sensor.

(Operations and Effects) In the present invention, even though a flat image position detection sensor is used, when the distance from the observation lens to the object becomes longer, the distance from the observation lens to the image position detection sensor increases. is configured so that the distance is shorter.

Therefore, a good sign image can be obtained regardless of the distance to the target object. In addition, as a sensor for detecting image position,
Since a planar shape can be used, there are no manufacturing problems, and it is also advantageous from the viewpoint of serialization (versatility).

(Example) Examples of the present invention will be described in detail below. FIG. 2 is a plan view showing a preferred embodiment of the present invention. In this embodiment, a mark T is formed on one object ◯ by irradiation with the light beam B. The image of this marker T is reflected by a cylindrical mirror M and then passes through a lens L. The image of the marker T that has passed through the lens L is once reflected by the conical mirror Mc, and then projected onto the planar image position detection sensor P. This sensor P
The configuration is such that the radial position of the marker image projected thereon is detected, and thereby the distance from the observation lens L to the object is measured. In the illustrated arrangement, it is exactly the same as the image position detection sensor P being located at the optimum imaging plane P. In this example, since the mark T is dot-shaped, regardless of the distance to the object,
The marker image on the image position detection sensor P does not become blurred.

Note that as the angle of the mirror approaches a plane, it approaches the case of a fixed focal point, and when it is a plane, it matches the case of a fixed focal point. In this case, although the imaging conditions are not improved, the length of the optical system in the optical axis direction can be shortened.

Figure 3 shows the optical distance detection method ROR3T (R
iken 0ptical Range Sensin
g Scheme for S1 face Trasi
FIG. ROR, ST is an annular pattern T (θ1) on the object surface.

This is a method of forming a pattern T(θ2), projecting this pattern onto the observation surface using an observation lens, detecting the radial position of the image in each direction, and detecting distance information to the target object surface in each direction. . Therefore, since the inclination information of the object surface can be obtained, it is extremely suitable for surface tracking in shape measurement and the like.

Now, the optimal imaging plane P is given by equation (2) and has a conical shape as shown in FIG.

The conical mirror Mc installed according to the present invention serves to bring the image position detection sensor P closer to the optimal imaging plane P even if the sensor P is planar.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the basic configuration of the present invention, Fig. 2 is a plan view showing a preferred embodiment of the invention, Fig. 3 is a plan view showing another embodiment of the invention, and Fig. 4 is a conventional FIG. 5 is a perspective view of another conventional optical distance sensing device. FIG. 5 is a plan view of another conventional optical distance sensing device. ○...Object, T...Sign, L...
...Observation lens, P...Sensor for detecting image position,
Mo...Conical mirror, B...Light beam. Engraving of drawings (changed to self-existence L) Procedural amendment (method) Director General of the Patent Office, Shinko 11, Indication of case Patent Application No. 207659 of 1985 2, Title of invention Optical distance detection device 3, Amendment Relationship with the case of the applicant (679) RIKEN 4, Agent 5, Date of amendment order November 26, 1985 As shown in the engraving and attached sheet of the drawings originally attached to the application (no changes in content) )

Claims (1)

[Claims] A mark on an object is projected onto an image position detection sensor through an observation lens, and the distance to the object is detected by detecting the position of the mark projected onto the optical sensor. In the optical distance detection device, a conical mirror is provided that reflects the light that has passed through the observation lens,
An optical distance detection device characterized in that a planar sensor is used as the image position detection sensor.