Kodak DryView 8150, Руководство по обслуживанию, Страница: 219 / 470

Section 6 -- Theory of Operation
6-17
2005 July Rev. B 7F3318
1. Synchronize pixel generation with the SOS detector in the Optics Module.
2. Position the image in the vertical direction on the film, under CPU control.
3. Adjust for the nonsymmetric axis of the Spinner Motor mount by varying the length of some pixels on
one of the two optics mirror facets. (See Pixel Stretch Correction on preceding page.)
4. Turn the laser off during part of each rotation to prevent light scattering as the end of the mirror rotates
through the beam axis. (See Laser Dead Time on preceding page.)
5. Present the same data for scanning by both optics mirror facets consecutively.
6. Send SOL (Start of Line) signals to the IMS.
7. Accept image data from the IMS in high speed bursts of up to 5 Mpixels per second.
8. Allow simultaneous output of pixel data during these high speed bursts.
9. Do parity checking of the pixel data and generate clearly visible artifacts if an error is detected.
10. Count clocks received from the IMS and written to the page. If the counts do not match the
programmed numbers, generate an error detectable by the CPU.
11. Generate a dc SOS (Start of Scan) detection level (settable by the CPU) to trigger the SOS detector
for the portion of the scan rotation where the laser beam crosses the SOS detector.
12. Allow access to the Media LUT by the CPU.
6-4-3. Laser Optics Subsystem
6-4-3-1. General
The IMAGER laser optics subsystem includes the following major components:
•
A cylindrical platen, on which the film is held motionless during image scanning.
•
An optics module, which delivers a scanning laser beam across the surface of the film.
•
An optics translation assembly, which translates the laser beam perpendicularly to move down the
film, scan line by scan line.
A simplified schematic diagram of the optics is shown in Figure 6-8. The optics module contains a 50 mW
solid state laser diode with an emission wavelength of 810 nm. These specifications match the spectral
sensitivity of the film used in the IMAGER. The laser beam is modulated by varying its drive current. The
laser beam is shaped by collimation and by passing it through a set of three lenses (not shown in
diagram) to focus the beam at the film plane. The laser path also contains a beam power attenuator,
which controls maximum exposure on the film surface. Basic scanning specifications are as follows:
•
Pixel matrix: 4620 by 5596
•
Spatial resolution: 12.8 lines per mm
•
Laser spot size: 40 um by 60 um
•
Power at film: 23.4 mW maximum
•
Exposure time 35 seconds