LASER CENTRALISER FOR X-RAY EMITTER Russian patent published in 2011 - IPC H05G1/00 A61B6/08 

FIELD: physics.

SUBSTANCE: laser centraliser for an x-ray emitter has a housing in which there is a laser range finder, the laser axis of which is parallel to the longitudinal axis of the x-ray emitter, two mirrors, the first made from organic glass and placed at the intersection of the axes of the laser and x-ray beams perpendicular to the formed plane at an angle of 45 degrees to the axis of the laser, and the second mirror is placed on the axis of the laser at an angle of 45 degrees to the said axis, and its centre lies at a distance A from the centre of the first mirror, which is equal to the distance from the said mirror to the focus of the x-ray tube on the axis of the x-ray beam, a television system consisting of a lens, a CCD matrix and a monitor, wherein the optical axis of the lens passes through the centre of the second mirror and coincides with the perpendicular running from the said centre to the axis of the laser. There is a light filter in front of the lens for increasing contrast of the images of laser structures on the object, and there is an annular structure of N>8 microlasers on the axis of the laser of the range finder, perpendicular to the axis and symmetrically placed about the axis at a distance B from the centre of the second mirror. Optical axes of the microlasers are inclined to the axis of the laser of the range finder at an angle α/2 to the planes formed by axes of the microlasers and the axis of the laser and which, after reflection from the first mirror, form on the object an image of the annular structure of laser spots, the dimensions and shape of which correspond to the size and shape of the zone illuminated by x-rays. The axis of the laser of the range finder after reflection from the first mirror coincides with the axis of the x-ray beam and forms on the object a laser spot which coincides with the point of intersection of the axis of the laser beam with the object and with the centre of the annular structure of laser spots formed by the annular matrix of the microlasers. The second mirror has a centre opening for passage of the beam of the laser range finder. The annular matrix of microlasers with diametre D lies at a distance B=D/2tg(α/2) from the centre of the second mirror, where α is the divergence angle of x-ray beams. The centraliser also includes a rectangular matrix of microlasers with an order of K*T, where K and T are dimensions of the radiographic film in the holder for radiographing. This matrix lies in the housing of the centraliser symmetrically about the axis of the x-ray beam. Optical axes of M>8 microlasers are parallel to each other and he axis of the x-ray beam and form on the object a rectangular structure of laser spots with dimensions K*T, which does not change when the distance from the object to the centraliser L changes and through which the ratio of dimensions of the zone of the object illuminated with x-rays and the actual zone for recording radiographic images, determined by dimensions of the radiographic film used, can be determined. For better distinction of this and the annular structure of laser spots, the radiation of microlasers which form the rectangular structure can be modulated with frequency F>=1-10 Hz, and the focal distance f of the lens of the television camera satisfies the condition f<R*L min/s, where L min is the minimum distance from the object to the centraliser in the working measurement range of these distances, c is the size of the CCD matrix of the television camera, R is the diagonal of the sheet of the radiographic film with dimensions K*T.

EFFECT: high reliability owing to prevention of faults during operation of the laser centraliser due to spurious glares on the surface of the mirror of the laser range finder.

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