The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 26, 1988
Filed:
Feb. 09, 1987
Herbert Fend, Maeder, AT;
Wild Heerbrugg AG, Heerbrugg, CH;
Abstract
A stylus is briefly placed on the surface coating of photographs for forming an artificial marking symbol on the coating. The stylus oscillates in the ultrasonic frequency range. Part of the oscillation energy of the stylus is converted into frictional heat producing a marking symbol in the coating in the form of a high contrast annular bead. The apparatus comprises a stylus, a mechanical lowering device, an electroacoustic transducer for producing the ultrasonic oscillations of the stylus, and a frequency generator, an amplifier and a voltage/current converter connected in series with the electroacoustic transducer. The transducer is supplied with a signal from the frequency generator, which signal is kept constant by a control circuit provided on the generator. The electroacoustic transducer comprises a resonator fixed to the stylus and a piezo-oscillator mechanically connected to the resonator and electrically connected to the voltage/current converter to match impedance and regulate the amplitude of the signal supplied at the piezo-oscillator.