JPS60235007A - Cylindrical pattern detector - Google Patents

Abstract

PURPOSE:To effect cost down, by installing in a light-receiving system of reflected light from a cylindrical specimen a frame provided with nearly the same curvature as the external curvature of the specimen and attaching to this frame a light guide leading the reflected light to a photoelectric sensor. CONSTITUTION:Parallel light fluxes from a light projecting system constructed with a source 1, such as a light emission diode, etc., cylindrical lens 2, and lens 3, etc. are projected on a cylindrical specimen A and their reflected light is received by a photoelectric sensor 7 composed of a linear self-scanning type image sensor through the light-guide imbedded in a frame 5 provided with a curved surface 4 of the same curvature as the external surface curvature of the specimen A. By this arrangement, distance between the specimen A and light-receiving end of the light-guide 6 remains constant in all positions and automatic conversion from a circle to a straight line is performed and accordingly, significant simplification of data processing can be accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylindrical pattern detection device used for detecting cylindrical (including columnar) objects such as irons and bottles during mass production processes.

Hitherto, as this type of detection device, devices using a flying spot scanner, a concave mirror, etc. have been used, but these have disadvantages in that the detection system is complicated and the price is high. In addition, when light is irradiated onto an object with a curvature on its outer surface, such as a cylinder or column, and the reflected light is received and detected by a photoelectric sensor, the reflected light is diffused by the curvature of the outer surface of the object. The problem is that the correction process is very complicated and the accuracy is poor.

An object of the present invention is to improve such conventional problems and to enable accurate detection of the pattern of a cylindrical object using a relatively simple and inexpensive detection means.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, A is a cylindrical object to be detected, and a light projection system that projects light onto the surface of the object is a light emitting diode, semiconductor laser, etc. It is composed of a light source 1, a cylindrical lens 2, a lens 3, etc., and is projected onto the surface of the subject as an Ht parallel light beam from the light source 1.

However, since the outer peripheral surface of the great person being tested is a curved surface, the parallel light beam projected onto the curved surface is diffused as shown in FIG. Therefore, as described above, if it is assumed that the reflected light is received by a normal planar photoelectric sensor B, the correction process will be extremely complicated.

Therefore, in the present invention, as shown in FIG. Wire-shaped light guides 6 are embedded in close contact with each other in a straight line, the tip of each light guide 6 faces the curved surface 4 of the frame 5, and the rear end is brought into close contact with the light receiving surface of a linear photoelectric sensor 7.

In this case, a linear self-scanning image sensor or an analog position sensor is suitable as the photoelectric sensor 7.

In this way, if the curvature of the object and the curvature of the frame 5 are the same, the distance between the outer peripheral surface of the object and the light receiving end of the light guide 6 is constant everywhere, and the conversion from a circle to a straight line is automatically performed. This greatly simplifies data processing.

FIG. 4 does not show another embodiment of the present invention, and as illustrated in FIG. A hood 9 is provided to restrict the diffusion of light from the inside. In this embodiment, if the 8 groups of light emitting elements are sequentially turned on by the drive circuit 10, the light source itself has a scanning property, so there is no need to use a self-scanning type photoelectric sensor 7, and a normal phototransistor or photoelectric sensor 7 is not required. A single sensor such as a diode can be used.

According to the present invention, the light receiving system is equipped with a frame 5 having a curvature similar to the curvature of the outer circumferential surface of the subject, and a large number of wire-shaped light guides 6 attached by embedding or other methods. It is possible to effectively correct the distortion of the reflected light caused by the cylindrical pattern, and as a result, the cylindrical pattern can be accurately detected using a relatively simple and inexpensive mechanism.

[Brief explanation of drawings]

FIG. 1 is a layout diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the state of diffusion of reflected light when a parallel beam of light is applied to a cylindrical object, and FIG. 6 is a diagram showing the main points of FIG. 1. FIG. 4 is a layout diagram showing another embodiment, and FIG. 5 is a sectional view showing an example of the light source. 1 is a light source, 2 is a cylindrical lens, 3 is a lens, 4
is a curved surface, 5 is a frame, 6 is a light guide, 7 is a photoelectric sensor, 8 is a light emitting element, 9 is a hood, 10 is a group of drive circuit pieces.

Claims (1)

[Claims] 1. A light projection system that irradiates light onto the outer peripheral surface of a cylindrical object;
In a circular pattern detection device comprising a light receiving system including a photoelectric sensor that receives the reflected light, the light receiving system includes a frame having a curvature that is approximately the same as the curvature of the outer peripheral surface of the subject,
A cylindrical pattern detection device characterized in that a light guide such as an optical fiber is attached to the frame to guide reflected light to a photoelectric sensor.