Patent 4948940 Issued on August 14, 1990. Estimated Expiration Date: June 16, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
A device (1) for programmed spot treatment of a body with a beam of rays, particularly a laser beam (7), using a lens system (4), in which the point of impact of the beam (7) describes a predetermined pattern on the surface of the body particularly a lacquer sealed rotary screen printing stencil 3a, as a result of a relative movement of the body with respect to the device. According to the invention the device (1) has means for maintaining a constant predetermined distance between the center of the lens system (4) and the center of the point of impact of the beam (7) of rays with the surface of the body. Said means for maintaining a constant distance comprise distance-determining means, preferably a scanner of the optical, inductive or capacitive type, for determining the distance of the surface of the body from a lens system (4) located between a light source and the body, displacement means (11,12,12',14,14',15), preferably electromagnets cooperating with anchoring plates and spring packets, for displacing the lens system, and control means, preferably a microprocessor, for controlling the displacement means (11,12,12',14,14',15) according to the difference between a set value and the measured value of the distance between the lens system and the surface of the body. The stencil 3a is supported by a roller 3.
Feinwerktechnik & Messtechnik, vol. 94, No. 1, Jan./Feb. 1986, pp. 37-39, Carl Hanswer Verlag, DE; E. Wagner: "Halbleiterlaser in Systemen der Messtechnik"