Claims
- 1. In an apparatus for imagewise exposing an infrared sensitive layer, the apparatus comprising:
- a support assembly including:
- a rotatable cylindrical surface having a longitudinal axis, and means for mounting said layer on the cylindrical surface, and
- a motor assembly for rotating the cylindrical surface;
- a laser assembly for producing an image modulated beam;
- an optical assembly including:
- a lens for focusing the directed beam at the layer on the cylindrical surface, and
- a focusing motor assembly for moving the lens with respect to the layer on the cylindrical surface to focus the modulated beam such that the focused modulated beam is adapted to engrave the layer;
- a modulated beam delivery carriage assembly including:
- a carriage for supporting the optical assembly,
- a linear track along which the carriage is adapted to move, the track parallel to the longitudinal axis, and
- a translator motor assembly for transporting the carriage along the track to scan the image modulated beam along the layer on the cylindrical surface at a carriage advance rate of about an exposing width of the modulated beam on the layer on the cylindrical surface;
- a computer assembly for (i) receiving, generating and/or storing image data representing an image to be exposed on the layer, and (ii) selecting exposure parameters from a set consisting of the cylindrical surface speed, the carriage advance rate, image placement coordinates on the layer, focusing position, and amplitude modulation level; and
- an electronic control assembly for receiving the image data and the exposure parameters from the computer assembly and processing the image data and the exposure parameters to control the support assembly, the laser assembly, the optical assembly, and the modulated beam delivery carriage assembly to expose the image in a spiral fashion in the layer;
- and wherein the improvement comprises:
- the focused modulated beam comprises infrared radiation having a peak power density of 0.1 megaWatts/cm.sup.2 to 17 megaWatts/cm.sup.2 and is adapted to provide an energy density of 0.5 Joules/cm.sup.2 to 5 Joules/cm.sup.2 on the layer.
- 2. The apparatus of claim 1, wherein:
- the laser assembly comprises:
- a laser for emitting an output infrared radiation beam having a M.sup.2 beam quality value of 4 to 8 and a maximum power of about 50-70 Watts;
- a laser power supply for energizing the laser; and
- an acousto-optic modulator assembly for modulating the laser output beam with image data and for producing an image modulated first order beam having a maximum power of about 22 to about 32 Watts; and
- the electronic control assembly is adapted to control the acousto-optic modulator assembly.
- 3. The apparatus of claim 2, wherein the acousto-optic modulator assembly comprises:
- an acousto-optic modulator for diffracting a first order beam portion of the laser output beam and passing a zero order beam portion of the laser output beam; and
- a beam dump for blocking either the first order beam portion or the zero order beam portion.
- 4. The apparatus of claim 3, wherein the acousto-optic modulator assembly is adapted to provide a modulation rate in a range of about 0.5 megabits/second to about 1.0 megabits/second.
- 5. The apparatus of claim 1, wherein the drum motor assembly is capable of rotating the cylindrical surface at a speed of about 500 to about 2500 revolutions per minute.
- 6. The apparatus of claim 1, wherein the lens is adapted to focus the directed beam to have a 1/e.sup.2 irradiance diameter of 15 .mu.m to 30 .mu.m at the infrared sensitive layer on the cylindrical surface.
- 7. The apparatus of claim 1, wherein the modulated beam has a wavelength of 780 to 2000 nanometers.
- 8. The apparatus of claim 1, wherein the laser output beam has a 1/e.sup.2 irradiance diameter at its waist diameter of 2 millimeters to 3 millimeters.
- 9. The apparatus of claim 1, further comprising a debris extraction system for removing ablated material, the electronic control assembly further adapted to control the debris extraction system.
- 10. The apparatus of claim 1, wherein the laser assembly includes a Nd:YAG laser.
- 11. The apparatus of claim 1, wherein the optical assembly further comprises:
- a reflector mounted on the carriage for directing the image modulated beam onto the layer on the cylindrical surface.
- 12. The apparatus of claim 1, wherein the electronic control assembly is further adapted to be used to select at least one exposure parameter from a set consisting of the cylindrical surface speed, the carriage advance rate, the image placement coordinates on the infrared radiation sensitive layer, the focusing position, and the amplitude modulation level.
- 13. The apparatus of claim 1, wherein the rotatable cylindrical surface comprises an outer surface of a sleeve.
Parent Case Info
This is a divisional of application Ser. No. 08/432,411, filed May 1, 1995.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
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A 43 13 111 |
Oct 1994 |
DEX |
Divisions (1)
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Number |
Date |
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Parent |
432411 |
May 1995 |
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