Laser Display System

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Laser Display System

• Christopher Nigro
• David Merillat

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Description / Overview (1)

• Produce a simple binary graphical display using a
  set of diode lasers.
• Support text displays (stationary and scrolling)
  with the possibility of images and simple video.
• Minimize lasers required for display.
• Should help minimize cost.
• Provide enough accuracy and synchronization to
  ensure resulting image appears consistent with
  minimal jitter and flicker.

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Description / Overview (2)
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Display Specifications
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Target Display Modes

• Target Deliverables
• Basic Text Display
• Display basic 8-point text.
• Scrolling Text Display
• Display scrolling 8-point text at a configurable
  speed.
• Pause Display
• Pause displays between commands.
• Goal Deliverables
• Binary Image Display
• Display ASCII-encoded binary images.
• Binary Video Display
• Display animation, or correlated sets of
  ASCII-encoded binary images.

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Analysis and Feasibility (1)

• Specification 60Hz Display
• Requires a 4-face mirror spinning at 900 RPM.
• Thus, required laser operating frequency must be
  approximately 50 kHz.
• Specification 16 x 100 Pixel Resolution
• Frame Size 200 Bytes
• Required Bandwidth 12 kB/s
• Expected Brightness Approximately 350 cd.

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Analysis and Feasibility (2)

• Horizontal Accuracy
• Requires electrical timing accuracy of
  approximately 40 us.
• Mirror mounting accuracy (horizontal) is not
  important and can be compensated for in software.
• Vertical Accuracy
• Requires vertical mirror mounting accuracy of
  approximately 0.5 degrees.

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Other Technical Difficulties

• Mirror Mounting
• Mirror faces not mounted on motor shafts axis of
  rotation.
• Causes nonlinearities in laser reflection angles.
• Frame Construction
• Many of the components in this system require
  accurate or precise mounting.
• Motor Speed Control
• If a decent synchronous motor is not found, a
  speed control system must be implemented to keep
  mirror rotation speed consistent.

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Project Status

• Current Activities
• Acquiring Components
• System Microprocessor Acquired and Functional
• Motorola MC68332 20 MHz Microprocessor
• Lasers, motor, and materials required for
  accurate construction and mounting of system
  components.
• Subsystem Design
• Motor Control
• Output FIFO Control
• Output Driver Channel

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Conclusion

• Questions?
• Comments?
• Suggestions?