发明申请
- 专利标题: POLARIZATION SENSITIVE FRONT PROJECTION SCREEN
- 专利标题(中): 极化敏感前投影屏幕
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申请号: US13504339申请日: 2010-11-10
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公开(公告)号: US20120212812A1公开(公告)日: 2012-08-23
- 发明人: Michael F. Weber , Yufeng Liu , Timothy J. Nevitt
- 申请人: Michael F. Weber , Yufeng Liu , Timothy J. Nevitt
- 申请人地址: US MN Saint Paul
- 专利权人: 3M Innovative Properties Company
- 当前专利权人: 3M Innovative Properties Company
- 当前专利权人地址: US MN Saint Paul
- 国际申请: PCT/US10/56175 WO 20101110
- 主分类号: G03B21/60
- IPC分类号: G03B21/60
摘要:
A projection system is disclosed, in which a screen may have improved rejection of ambient light by having a high reflectivity at low angles of incidence for a polarization parallel to that of the projector, a low reflectivity at high angles of incidence for a polarization parallel to that of the projector, and a low reflectivity at both low and high angles of incidence for a polarization perpendicular to that of the projector. In some embodiments, for p-polarized light polarized parallel to the projector, the power reflectivity is high at low angles of incidence and decreases to a low value at high angles of incidence. In some embodiments, for p-polarized light polarized perpendicular to the projector, the power reflectivity is low at low angles of incidence. In some embodiments, for s-polarized light polarized perpendicular to the projector, the power reflectivity remains low at all angles of incidence. In some embodiments, the screen includes a thin film structure that has alternating quarter-wave layers of isotropic and birefringent materials, which are refractive-index-matched for light polarized perpendicular to the projector, which form a high reflector at normal incidence for light polarized parallel to the projector, and which exhibit Brewster's angle effects for p-polarized light polarized parallel to the projector at high angles of incidence. The Brewster's angle effect may be reached by use of a light-scattering layer that increases the effective incident refractive index.
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