Head-up display with polarized light source and wide-angle p-polarization reflective polarizer
First Claim
1. A system for displaying information to a viewing position, comprising:
- a window member having a target area and at least a first exposed window surface at the target area, the first exposed window surface having associated therewith a first normal axis;
a display source that emits polarized light toward the target area along an illumination axis that makes an acute angle θ
1 with respect to the first normal axis, the emitted light being substantially p-polarized and comprising at least one visible wavelength of interest; and
a reflective polarizer disposed proximate the target area to reflect at least some of the p-polarized light from the display source towards the viewing position;
wherein the reflective polarizer has a higher reflectivity for p-polarized light than for s-polarized light at the at least one visible wavelength of interest over an angular range of incidence angles that includes the angle θ
1.
1 Assignment
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Accused Products
Abstract
A head-up display includes a projection system and a window having a target area where a reflective polarizer is positioned to reflect light from the projection system to a viewing area. Light from the projection system is p-polarized and strikes exposed window surface(s) at an acute angle to reduce or eliminate multiple or “ghost” images. The acute angle is closely matched to a Brewster angle of the exposed window surface(s). The reflective polarizer includes a multilayer stack with refractive indices of individual layers chosen to reflect p-polarized light substantially more than s-polarized light over a wide angular range that includes the acute angle. The reflective polarizer also can reflect infrared light to reduce cabin heating from solar radiation.
83 Citations
27 Claims
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1. A system for displaying information to a viewing position, comprising:
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a window member having a target area and at least a first exposed window surface at the target area, the first exposed window surface having associated therewith a first normal axis;
a display source that emits polarized light toward the target area along an illumination axis that makes an acute angle θ
1 with respect to the first normal axis, the emitted light being substantially p-polarized and comprising at least one visible wavelength of interest; and
a reflective polarizer disposed proximate the target area to reflect at least some of the p-polarized light from the display source towards the viewing position;
wherein the reflective polarizer has a higher reflectivity for p-polarized light than for s-polarized light at the at least one visible wavelength of interest over an angular range of incidence angles that includes the angle θ
1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for displaying information to a viewing position, comprising:
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a window member having a target area and at least a first exposed window surface at the target area, the first exposed window surface having associated therewith a first normal axis;
a display source that emits polarized light toward the target area along an illumination axis that makes an acute angle θ
1 with respect to the first normal axis, the emitted light being substantially p-polarized and comprising at least one visible wavelength of interest; and
a reflective polarizer disposed proximate the target area to reflect at least some of the p-polarized light from the display source towards the viewing position;
wherein the first normal axis and the illumination axis define a first plane, and the reflective polarizer is substantially transparent for s-polarized light and substantially reflective for p-polarized light at the at least one visible wavelength of interest for light incident in the first plane over an angular range that includes the illumination axis. - View Dependent Claims (16, 17, 18)
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19. A system for displaying information to a viewing position, comprising:
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a window member having a target area and at least a first exposed window surface at the target area and a second exposed window surface opposed to the first exposed window surface, the first exposed window surface having associated therewith a first normal axis;
a display source that emits polarized light toward the target area along an illumination axis that makes an acute angle θ
1 with respect to the first normal axis, the emitted light being substantially p-polarized and comprising at least one visible wavelength of interest; and
a reflective polarizer disposed proximate the target area to reflect at least some of the p-polarized light from the display source towards the viewing position;
wherein the reflective polarizer is disposed between the first and second exposed window surfaces, and the reflective polarizer reflects p-polarized light more than s-polarized light for light at the at least one visible wavelength of interest and incident along the illumination axis. - View Dependent Claims (20, 21, 22)
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23. A component suitable for use in a HUD system, comprising:
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a window member having a target area and at least a first exposed window surface at the target area, the first exposed window surface having associated therewith a first normal axis and a Brewster angle θ
B; and
a reflective polarizer disposed proximate the target area;
wherein the reflective polarizer has a higher reflectivity for p-polarized light than for s-polarized light for at least one visible wavelength of interest and for light having a first incidence direction that makes an angle θ
B with the first normal axis. - View Dependent Claims (24, 25, 26, 27)
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Specification