SU1395946A1 - Device for checking surface roughness - Google Patents

Abstract

The invention relates to a measurement technique and can be used to control the surface roughness of the dark field method. The purpose of the invention is to reduce the longitudinal: dimensions of the device for. the expense of using simple positive lenses in the optical system of the device. The device contains a source of radiation I installed on the same optical axis, positive lenses 2 and 3, and a recorder 4. Lens 2 together with the central zone of the lens 3 are built on the test surface 5 an image from the incident site of the radiation source 1. Upon reflection of radiation from the surface 5, a part of the rays, which fall onto the surface free from microdelectures, is reflected mirrored, and a part scatters on the microdetectors and falls on the peripheral zone of the lens 3, which forms in the plane of the recorder 4 an image of bright microdefects against a dark background. The specularly reflected rays through the central zone of the lens 3 and the lens 2 return back to the radiation source 1 and do not reach the recorder 4. 1 il. i (L

Description

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The invention relates to a measuring technique and can be used, in particular, to control the surface roughness, with

The purpose of the invention is to reduce the longitudinal dimensions of the device by using a simple positive lens instead of a complex negative lens with a hole, and also due to the fact that the equivalent focal distance of the system of two positive lenses is less than the equivalent focal length of the system from the positive and negative lenses.

The drawing shows a schematic diagram of a device for monitoring surface roughness.

The device contains a source of radiation 1, positive lenses 2 and 3 and a recorder 4 mounted on one optical axis 20.

The radiation source 1 together with the 25 lens 2 of a smaller diameter and the central zone of the lens 3 of a larger diameter form a short-focus illumination channel, and the recorder 4 together with the peripheral zone of the lens 3 30 of a larger diameter form a long-focus reception channel whose aperture in the space of objects exceeds the aperture of the light channel ,

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Lenses 2, 3 can be flat-tinted, double-convex or positive meniscuses. A miniature incandescent lamp can be used as the radiation source 1, but the best i 40 results are obtained by using LEDs with a narrow radiation indicatrix. The recorder A can be a photodetector that allows you to adjust and evaluate the value of the diffuse component of the radiant flux reflected from the monitored surface 5, or a conventional microscope if it is reasonable to determine the magnitude of the roughness by the geometrical characteristics 50 of the visually observed microdefects of the monitored surface 5.

The device works as follows

Claims (1)

The diverging beam of radiation from the radiation source 1 passes through the positive lens 2 of a smaller diameter onto the central zone of the positive lens 3, which converts it into a converging beam centered on the test surface 5 and builds on this surface an image of the radiating surface of the radiation source 1. When radiation is reflected from the monitored surface 5, a part of the rays falling on a surface free from microdefects is mirrored, and a part is scattered on the microdefects of the rough surface. The mirrored component of the reflected flux returns back to the radiation source 1 through the central zone of the lens 3 and the lens 2 and is further examined. The rays scattered on microdetects fall on the peripheral zone of the positive lens 2, which forms in the plane of the recorder 4 an image of the microdefects of the monitored surface 5. Since only those rays that are reflected from micro defects fall into the recorder 4 from the rest of the surface, returning back to the SOURCE of the 1 radiation, the microdefects are observed in the recorder 4 as light objects on a dark background. Measuring the magnitude of the scattered component of the reflected flux, for example, by a photodetector or by determining the geometric parameters of micro-defects when visually observed, can be judged on the surface roughness class 5, A device for monitoring surface roughness, containing a radiation source, a positive lens mounted along the path of radiation, and a recorder, characterized in that in order to reduce the longitudinal dimensions of the pore, it is equipped with a second positive lens mounted between the radiation source and the first positive lens. VNIIGO Order 2485/40 Circulation 680 Production polygr, pr-tie, Uzhgorod, st. Project, 4 Subscription