Invention Grant
US08651726B2 Efficient polarized directional backlight 有权
高效极化方向背光

  • Patent Title: Efficient polarized directional backlight
  • Patent Title (中): 高效极化方向背光
  • Application No.: US13470291
    Application Date: 2012-05-12
  • Publication No.: US08651726B2
    Publication Date: 2014-02-18
  • Inventor: Michael G. Robinson
  • Applicant: Michael G. Robinson
  • Applicant Address: US CA Beverly Hills
  • Assignee: RealD Inc.
  • Current Assignee: RealD Inc.
  • Current Assignee Address: US CA Beverly Hills
  • Agent Neil G. J. Mothew; Darlene K. Kondo
  • Main IPC: F21V7/04
  • IPC: F21V7/04
Efficient polarized directional backlight
Abstract:
By introducing a stack of alternating high and low index dichroic material layers on the exit surface of a waveguide for a wedge type directional backlight, natural reflectivity differences between polarized components can be increased, effectively reflecting the vast proportion of S-polarized light rays, while at the same time transmitting the P-polarized light rays, of light impacting the exit surface of the waveguide at an angle sufficient to exit the waveguide. This recovers polarization in wedge type backlight systems, increasing illumination exiting the waveguide. Also, on the back reflecting surface of the waveguide, a birefringent material can be added to efficiently transform S-polarized reflected light from the dichroic stack, into returning P-polarized light. Because returning rays that are now P-polarized by the birefringent material have already achieved the critical angle for exiting the waveguide, the rays transformed to P-polarization can now also exit the waveguide, increasing waveguide illumination.
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