SU1249325A1 - Device for checking roughness of surface - Google Patents

Abstract

The invention relates to a control and measuring technique and can be used, in particular, to control the surface roughness according to the dark field method. The purpose of the invention is to reduce the size and simplify the design by using simple lenses with spherical surfaces in the optical system, which are simultaneously used in lighting and receiving optical systems. A device for monitoring surface roughness contains a radiation source, an illumination and receiving optical systems and a recording device. The receiving optical system is made in the form of two components arranged in series on the optical axis of the device, the first of which is a positive lens, the second is negative of a linz with a focal distance smaller than the focal length of a positive lens, and a hole in its center. The function of the illumination optical system is performed by the central zone of the positive lens, equal to the hole in the negative lens. Measuring the value of the scattered component of the reflected flux by a photodetector or determining the geometrical parameters of microdefects upon visual observation, judging the class of surface roughness. 1 il. (O (L to 4 CO oo 1C sd

Description

The invention relates to measuring technique and can be used, in particular, to control the surface roughness using the dark field method.

The purpose of the invention is to reduce the size and simplify the construction by using the optical system of simple lenses with spherical surfaces that are simultaneously used in the. lighting and receiving optical systems.

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

The device contains a source of radiation 1, a recording device 2, an illumination and receiving optical systems. The receiving optical system is designed as two components arranged in series on the optical axis of the device, the first of which is a positive lens 3,

positive lens 1

at a distance not

ten

more than its focal length. The focal length of the positive lens 3 can be any within the limits allowed by the design of the device, and the method of its installation with respect to the test surface.

The device for controlling surface roughness works in the following way.

The flow rate of the beam of rays from the radiation source 1 passes a hole in the negative lens 4, hits the central zone of the positive lens 3, which converts it into a convergent beam centered on the test surface 5 and builds on the tS of this surface an image of the radiating platform of the radiation source 1. Upon reflection of radiation from the monitored surface 5, a portion of the rays falling on a surface free from microdefects.

the second one - the negative lens 4 with a focus is reflected mirror-like, and a part of the pajcce HBaeT distance smaller than the focal length of the positive lens 3, is made with a hole in its center. The role of the illumination optical system is performed by the central zone of the positive lens 3, which is equal to the hole in the negative lens 4.

Lenses 3 and 4 have spherical surfaces. Lens 3 can be plano-convex, double-convex or positive meniscus. Lens 4 may be flat-cond on the microdefects of a rough surface. The mirrored component of the reflected flow returns to the illumination system through the central zone of the lens 3 and is not used in the future. 25 The rays scattered on microdefects fall on the peripheral zone of the positive lens 3, which, together with the negative lens 4, forms in the plane of the recording device 2 an image of the microdefects controlled by the surface, double-bent or negative means 5. Since it is in the recording device 2, it’s low. As a source of radiation, only those rays that are reflected can be used miniature light from microdefects, and the rays reflected

from the rest of the surface 5 are returned to the lighting system, the microdefects

glowing, but the best results are obtained by using LEDs with a narrow indicatrix of radiation. A recording device 2 can be a photodetector, which allows recording and estimating the value of the diffuse component reflected from the monitored surface 5, or a conventional microscope, if it is reasonable to determine the magnitude of the sharpness by the geometric characteristics of the visually observed microdefects and the characteristics of the visually observed microdefects of the monitored surface.

In order to ensure minimum energy loss and maximum image contrast, the monitored surface 5 is placed at a distance of less - but more

the focal length of the receiving optical system, and the radiation source 1 and the recording device 2 are installed in the image planes of the monitored surface 5 by the receiving and illumination optical systems. Minimum longitudinal

are observed in the recorder — 2 as bright objects against a dark background. Measuring the value of the scattered component of the reflected flux by a photodetector or determining the geometrical parameters of microdefects upon visual observation can be judged on the class of surface roughness.

Claims (1)

Invention Formula A device for monitoring surface roughness, containing a radiation source, an illumination and receiving optical systems, and a recording device, characterized in that, in order to reduce the size and simplify the design, the receiving optical system is designed as two components arranged in series on the optical axis of the device, the first of which is a positive lens, the second is a negative lens with a focal length smaller than the focal length of 50 the dimensions of the device are provided if a positive lens, made with a hole, is used; the negative lens 4 is located behind in its center. positive lens 1 at a distance not more than its focal length. The focal length of the positive lens 3 can be any within the limits allowed by the design of the device and the method of its installation with respect to the test surface. The device for controlling surface roughness works in the following way. The flow rate of the beam of rays from the radiation source 1 passes a hole in the negative lens 4, hits the central zone of the positive lens 3, which converts it into a convergent beam centered on the test surface 5 and builds on this surface an image of the radiating surface of the radiation source 1. Upon reflection of radiation from the monitored surface 5, a portion of the rays falling on a surface free from microdefects. is mirrored, and a part of pajcceHBaeTc on microdefects on a rough surface. The mirrored component of the reflected flow returns to the illumination system through the central zone of the lens 3 and is not used in the future. The rays scattered on the microdefects fall on the peripheral zone of the positive lens 3, which, together with the negative lens 4, forms in the plane of the recording device 2 an image of the microdefects of the test surface 5. As only the rays reflected in the recording device 2 fall into the recording device 2 as light objects on a dark background. Measuring the value of the scattered component of the reflected flux by a photodetector or determining the geometric parameters of microdefects upon visual observation, one can judge the class of surface roughness. Invention Formula A device for monitoring surface roughness, containing a radiation source, an illumination and receiving optical systems, and a recording device, characterized in that, in order to reduce overall dimensions and simplify the design, the receiving optical system is designed as two components arranged in series on the optical axis of the instrument. of which - a positive lens, the second - a negative lens with a focal distance smaller than the focal length of lens, made with a hole in its center.