Raster output scanners

Claim 2

A raster output scanner capable of high-speed, high-resolution writing of images in response to image signals on a record member, comprising in combination: a) a source beam (10); b) means (25) for separating the source beam into at least two parallel beams; c) an acousto-optical light intensity modulator (40) for modulating each of the beams separately, the modulator including an acousto-optic medium sized to provide a separate modulation channel (44) for each of the beams without intruding into adjoining modulator channels, the separating means separating the beams by an amount such that each beam impinges on a separate modulation channel, a separately-controllable ultrasonic transducer for each of the beams disposed in operative relation with each of the modulation channels for generating acoustic waves in each of the modulation channels, and control circuit means for intensity modulating the acoustic waves output by each of the transducers in accordance with separate lines of image signals; d) means for simultaneously projecting the beams through the modulating channels in a direction transverse to the direction of propagation of the acoustic waves, to produce separate moving images of information corresponding to each of the image signal lines; e) optical means (80, 91) for simultaneously projecting and scanning the intensity-modulated beams onto the record member (88) at spaced points in a manner such that the speed of the moving images is substantially equal to, and in the opposite direction to, the speed with which the beams are scanned; and f) pulse polarity reverse logic circuit means for reversing the voltage polarity of alternate bits in each of the image signals in each of the lines thereby to increase the image contrast of the intensity-modulated beams at the record member.

Claim 3

The scanner according to claim 1 in which the beam separator separates the beams by the width of at leasttwo image lines.

Claim 4

The scanner according to claim 2 including: means to recombine the beams following modulation so that the beams simultaneously write adjoining image lines on the record member with each scan.

Claim 5

An optical data recording system for the simultaneous high optical resolution recording of plural image lines from a like number of discrete video bit streams on a moving light-sensitive member comprising: a) means for providing a beam of radiant energy; b) means for separating the beam into at least two parallel image writing beams; c) an acousto-optical light intensity modulator in the path of the writing beams for modulating each of the writing beams separately to provide plural discrete information channels, the modulator including an acousto-optic medium, the writing beams impinging on the medium at different points so that the writing beams pass through separate non-overlapping areas of the medium, a separately-controllable ultrasonic transducer for each of the writing beams disposed in operative relation with the medium for generating acoustic waves confined to the medium separate areas, and control circuit means for intensity modulating the acoustic waves output by each of the transducers separately in accordance with the video bit streams; d) means for projecting the writing beams through the medium in a direction transverse to the direction of propagation of the acoustic waves, to produce in the medium separate moving images of information corresponding to each of the video bit streams; e) optical means interposed in the path of the intensity-modulated beams for simultaneously projecting the image lines onto discrete areas of the member, the optical means including a scanning element for simultaneously scanning the writing beams across the light-sensitive member whereby the speed of the moving images is substantially equal to, and in the opposite direction to, the tangential component of motion of the writing beams, the scanning element scanning the writing beams across the light-sensitive member in a direction substantially perpendicular to the direction of movement of the light-sensitive member; and f) pulse polarity reverse logic circuit means for reversing the voltage polarity of alternate bits in each of the video bit streams thereby to increase the resolution of the intensity-modulated writing beams as recorded on the light-sensitive member.

Claim 6

An optical data recording system for the simultaneous high optical resolution recording of plural image lines from a like number of discrete video bit streams on a moving light-sensitive member comprising: a) means for providing a beam of radiant energy; b) means for separating the beam into at least two parallel image writing beams; c) an acousto-optical light intensity modulator in the path of the writing beams for modulating each of the writing beams separately to provide plural discrete information channels, the modulator including an acousto-optic medium, the writing beams impinging on the medium at different points so that the writing beams pass through separate non-overlapping areas of the medium, a separately-controllable ultrasonic transducer for each of the writing beams disposed in operative relation with the medium for generating acoustic waves confined to the medium separate areas, and control circuit means for intensity modulating the acoustic waves output by each of the transducers separately in accordance with the video bit streams; d) means for projecting the writing beams through the medium in a direction transverse to the direction of propagation of the acoustic waves, to produce in the medium separate moving images of information corresponding to each of the video bit streams; e) optical means interposed in the path of the intensity-modulated beams for simultaneously projecting the image lines onto discrete areas of the member, the optical means including a scanning element for simultaneously scanning the writing beams across the light-sensitive member whereby the speed of the moving images is substantially equal to, and in the opposite direction to, the tangential component of motion of the writing beams, the scanning element scanning the writing beams across the light-sensitive member in a direction substantially perpendicular to the direction of movement of the light-sensitive member; and f) pulse polarity reverse logic circuit means for reversing the voltage polarity of alternate bits in each of the video bit streams thereby to increase the resolution of the intensity-modulated writing beams as recorded on the light-sensitive member.

Claim 7

The system according to claim 4, in which the beam separating means comprises: a) a light-transmissive substrate disposed astride the path of the beam, the substrate being disposed at an angle with respect to the optical axis of the beam; b) a linear array of partially-reflecting surfaces on the beam exit side of the substrate, the degree of reflectivity of the partially-reflecting surfaces progressively decreasing in steps, the number of the partially-reflecting surfaces being one less than the number of writing beams; and c) a substantially completely reflecting surface on the beam entrance side of the substrate, whereby each beam portion reflected from the partially reflecting surfaces are in turn reflected by the completely reflecting surface to impinge on the next succeeding one of the partially reflecting surfaces whereby to provide the parallel writing beams.

Claim 8

The system according to claim 4 or 5, in which each of the control circuit means includes: a) a source of high-frequency signals; b) means for mixing the output of the reverse logic circuit means with the output of the high-frequency signal source to provide a high-frequency signal input modulated by the video bit stream for driving the transducer associated therewith; and c) means for applying the signal input to the transducer.

Claim 10

The system according to claim 7 in which the widest dimension of the beam is at least sufficient to expose two pixels.