Message character image projection control system

Claim 1

In a message character image projection control system including an array of character shaped light forming window means, a source of light and means for exposing the window means of said array to light from said source, and optical means positioned along an optical axis of said system for establishing individual optical path relationships between each said window means of the array and said optical axis, wherein the improvement comprises: (a) said optical means including first and second acousto-optic optical path relationship control means and each of said control means including an ultrasonic frequency transducer and an interaction medium positioned along said optical axis, and a source of ultrasonic frequency voltages and circuit means for connecting said transducers to this source of voltages for an establishing of any of a number of different acoustic wave light reflecting conditions within the interaction medium of said first control means and within the interaction medium of said second control means, each said optical path relationship corresponding, respectively, to a combination of said light reflecting conditions of said first and second control means; (b) means for establishing a predetermined one of said light reflecting conditions within said medium of the first control means and a predetermined one of said light reflecting conditions within said medium of the second control means and establishing a corresponding one of said optical path relationships between a predetermined one of the window means of said array and said optical axis; (c) said exposing of the window means of said array to light from said source including a flooding of the entire array of said window means, simultaneously, with light from said source of light, said flooding of the entire array of window means allowing a viewing of an optical image of said predetermined one of the window means from along said optical axis.