| 摘要 |
1,264,492. Light projecting device. G. CORADI A. G. Feb. 3, 1969 [Feb. 7, 1968], No. 5685/69. Heading G2J. Apparatus wherein a light spot rapidly draws small symbols upon a photographic layer in response to stored information fed to the moveable work carriage of an automatic drafting machine supporting said apparatus, the light spot intensity being controlled in accordance with its linear speed and symbol line width required. The apparatus comprises a light source 1 producing a beam which is focused by lenses 3a, 3b upon the aperture of a diaphragm 4 and is subsequently split by a dichroic mirror 6 which transmits a first beam part to a photo-cell 10 connected via a servomotor to appropriately move a neutral wedge filter 9 in response to the light intensity falling thereupon and which reflects a second beam part to be focused on a selected aperture of a diaphragm 7, the image thereof being reproduced for movement in two coordinate directions upon a photographic layer S by passage of the second beam part through first and second telecentric ray producing systems and a diaphragm 18 wherein the first system comprises objectives 11, 16, mirrors 13, 13a, 15, 17 and a rotatable mirror 14 of a mirror galvanometer which deflect the second beam part in one co-ordinate direction within the aperture of diaphragm 18 and the second system comprises objectives 20, 25, mirrors 19, 22, 23, 23a, and a rotatable mirror 24 of a second mirror galvanometer which deflects the second beam part in the other mutually perpendicular co-ordinate direction. Termination and commencement of line drawing is determined by a shutter 8 whilst line thickness is dependent upon the aperture in the diaphragm 7, a displaceable condenser 5 ensuring that only the aperture chosen is fully illuminated. The diaphragm 7 may be provided with a plurality of different sized apertures and mounted for rotation, so that an aperture may be selectively aligned with the incident beam or the diaphragm 7 may be non-rotatable, but replaceable by another having a different sized aperture. |
