The method of determining the position of a defect in a transparent stone

 

(57) Abstract:

Usage: while processing a transparent stones PC, namely how to determine the position of the defect in PC mainly with higher refractive index. The inventive measurement is carried out at the premises of PC in different environments using computational techniques. 1 C. p. F.-ly, 2 Il.

The invention relates to the field of processing transparent stones mainly with a higher refractive index, for example diamonds, and in particular to methods of determining the position of the defect in crystals and blanks after various technological operations, may find application in the production study and sorting stones, preparations and products from them.

In the processing of transparent stones, particularly diamonds, especially in the manufacture of jewelry inserts (diamonds), often solves the problem that it is better to cut or leave the inside of the product defect. For solving the problem requires accurate information about the position of a defect in the crystal, but its getting complicated by the fact that visible over the edges of the image defect does not correspond to its true position.

There is a method of studying the internal features is the PTO stone (B. Anderson The definition of precious stones. M. Mir, 1983, S. 62). It uses a special immersion baths (Reid, P. J. Gemological dictionary. L. Nedra, 1986, S. 74). However, the immersion liquid with a high refractive index of the road, and often highly toxic, such as feldioara with a refractive index of 1.85 or liquid-based iodine methylene, sulfur and iodine arsenic with a refractive index of up to 2.06 (Anderson B. Definition of precious stones. M. Mir, 1983, S. 54). For diamond immersion liquid is not selected.

Known methods of determining the position of a defect in a transparent stone by viewing through a magnifying glass or microscope at different degrees of magnification (Epifanov Century. And. and other processing diamonds. M High school, 1987, S. 84). But the true position of the defect does not match the apparent position due to distortion caused by refraction of light at the boundary of the air face of the crystal.

The closest in characteristics to the proposed technical solution (prototype) is a method of determining the position of a defect in a transparent stone, which consists in viewing the inner part of the crystal through a planar face. However, the crystal is set in the field zren the UYa different degrees of increase. The apparent depth of the defect is defined as the difference in the readings on the limb of the subject table in terms of focusing on the surface of the face and on the defect. The actual depth of the defect is determined by adjusting the refractive index of the material of the stone. If necessary, conduct measurements across the other faces of the crystal (ibid, p. 85).

The main disadvantages of the prototype are low accuracy and low productivity. Lack of precision is due to the fact that when a small degree of increase in low accuracy of the focus due to the large depth of field. To decrease depth of field by increasing the magnification of the microscope, but this decreases the field of view, therefore, the area of increasing the accuracy of the method is limited to small stones. Low productivity due to the need of application of geometric calculations, and they require to make an additional measurement parameters such as the angle between the normal to the face and the optical axis of the measuring device.

The objective of the invention is to develop a more accurate and more efficient method of determining the position deliemma the method comprises the following steps: the orientation of the crystal so that through the flat face of the crystal was visible defect, view the inner part of the crystal, in accordance with the invention to Orient the crystal so that through different faces were seen at least two images of the investigated defect in the crystal, record the position of these images in the image plane twice when placing a crystal in two different media with different refractive indices, determine the position of the defect in the image plane at the point of intersection of the lines connecting the displacement of the image defects in each of the faces.

In the result of light refraction at the boundary of the crystal visible image defect is shifted relative to its true position. So there are the crystal orientation in which one defect is visible simultaneously from different sides, and the position of the visible image depends on the refractive index at the boundary of the crystal. When changing the environment in which you have placed the crystal, changes the refractive index at the boundary of the crystal, therefore, change the position of the visible image of the defect on the faces. From the laws of geometrical optics, it follows that all the visible image inhomogeneity and its true position the system. This visible image of heterogeneity is committed to its true position when approaching the refractive index of the medium to the refractive index of the crystal. In other words, the image defect observed in different environments through the same face of the crystal, in the image plane lie on the same straight line passing through the true position of the defect. To get this straight enough to register the visible position of a defect in the crystal when it is placed in two different environments with different refractive indices. If the image inhomogeneities observed in two or more faces, you can get several such lines, the intersection of which is the projection of the true position of the defect on the image plane in a direction parallel to the optical axis of the recording system.

In addition, we offer after twice performed for different orientations of the crystal described measurements to determine the spatial location of the defect at the point of intersection parallel to the optical axis of the recording system of lines passing through the position of the defect in the image planes for each measurement.

It is also proposed as a recording system of the aircraft.

The accuracy and performance of the proposed method due to the fact that in one orientation of the crystal it is possible to define two coordinate position of the defect relative to any fixed element of the crystal. In addition, the method is automated during its implementation using computational and television technics and the creation of special software.

Thus, the combination of the above features allows you to achieve this before the invention of the task.

The absence of any of these signs of an obstacle to implementation of the method, therefore, concluded according to their concept of "essential features".

The applicant did not know the technical solutions of the above essential features, therefore, the present technical solution to meet the requirement of novelty.

The invention is illustrated by the optical scheme of the installation for implementing the method shown in Fig.1; Fig.2 shows an example of a projection onto the image plane of the crystal visible image defect in it and shows the determination of the true position of the defect.

The method is slideways in the immersion bath 4-created in the environment 5, which is used, for example, air. Crystal 1 are oriented so that through different faces were seen at least two images of the defect 7 in the crystal 1. The tray 4 is illuminated with diffuse light source 6. The defect 7 in the crystal 1 is observed, for example, through two faces 8 and 9 of the crystal 1, and the visible two imaginary image 10 and 11 of the defect 7. The image, for example, through the lens 12 and the aperture 13 is logged, for example, the camera 14.

The thus created a television image is displayed on the display screen, blending with the image from the computer. This allows using special software to register on the screen visible position of defects in the changing environment in which the crystal, and to determine the true position of the defect.

Determination of the true position of the defect in the image plane as follows. Picture crystal 1 (Fig.2) projected on the plane of the image displayed on the display screen of the computer. Visible through the faces 8 and 9 image 10 and 11 of the defect 7 are registered and stored with the help of software. Then changing the environment in which you have placed the crystal 1, for example, by pouring in Immers the thought of conditions 12 and 13. New clauses 12 and 13 of the defect 7 is also recorded and stored with the help of software. Then posted straight lines 14 and 15 through the registered position of the visible images, respectively 11-13 10-12 and defect 7. The true position of the defect in the image plane is located at the point of intersection of the lines 14 and 15. If necessary, the measured coordinates of the true defect position 7 relative to any fixed crystal element 1, for example pre-marked vertices. These coordinates define the position parallel to the optical axis of the recording system of the line passing through the position of the defect.

To determine the spatial position of the defect is measured twice. To do this, after the described measurement changes the orientation of the crystal 1 (Fig.1), for example, by rotation of the mandrel 2 around its axis to obtain a second orientation of the crystal 1, in which through different facets visible to at least two images of a defect in the crystal. The angle of rotation of the mandrel is registered. The measurements are repeated to obtain the second pair of coordinates that define a new position parallel to the optical axis of the recording system of the line passing through the position defec the position of the defect 7 at the point of intersection of the obtained lines, passing through the position of the defect in the image planes for each measurement.

1. The METHOD of DETERMINING the POSITION of a DEFECT IN a TRANSPARENT STONE, at which the crystal is oriented relative to the recording system so that through the face of the crystal was visible defect, followed by viewing the inner part of the crystal, wherein the crystal is oriented so that the defect was visible at least through one face of the crystal, put the crystal in two different media with different refractive indices, each time recording the position of the image defect in the image plane, is carried out in the image plane straight through the image of a defect on each of the faces, the intersection point which characterizes the position of the defect.

2. The method according to p. 1, characterized in that the crystal is additionally oriented in the other direction, repeat all the measurements for this crystal position and the defect position is determined by the point of intersection of the lines passing through the image defect in the image plane for each measurement.

 

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