GB490910A - Pocket device for gauging or comparing the sizes of blood-cells optically - Google Patents

Abstract

490,910. Gauging-apparatus. ZEISS, C., [Firm of]. Feb. 21, 1938, No. 5351. Convention date, March 2, 1937. [Class 106 (ii)] Comprises optical apparatus for comparing the size of the diffraction rings of a blood smear to be examined with a representation of the diffraction rings of a normal blood smear. In the form shown in Figs. 1, 2, 3, a glass rod 1 of rectangular cross-section has a face 2 square to its axis and a face 3 forming part of a lens whose optical axis lies in the surface 4 of the rod 1. A support 4 carries a glass plate 6. The face 2 bears three lines R, B, G, concentric to a point M in the optical axis, the line G being a semicircle and lines R, B quadrants, and also carries a diametrical scale 7. The lens 3 and lines R B G are formed so that the eye A sees a sharp image in which the lines R, B, G would represent the medial lines of the red, yellow, and blue rings seen if normal red corpuscles were being viewed on the plate 6. In use the plate is smeared with the blood to be tested and the apparatus viewed against a distant light source when rings with medial circles R", G", B<11> appear simultaneously with images R<1>, G<1>, B' of lines R, G, B. In a second form, a cylindrical tube contains at one end a mark plate and at the other a half lens, while in the tube is a slit to receive in the field not occupied by the half lens, a glass plate smeared with the specimen of blood. The mark plate has three lines which appear tangent to the medial circles of normal rings and displaced when the rings are not normal. Further forms are described in which lenses and inclined mirrors are used in one of which is a light source.