Display system and light control film therefor
A head-up display for a vehicle comprises an optical component having a reflective surface arranged, during head-up display operation, in a configuration that is conducive to sunlight glare. A light control layer is disposed on the optical component to receive sunlight on an optical path to the reflective surface. The light control layer comprises a sunlight-receiving surface and a core material separating an array of louvres. The sunlight-receiving surface of the light control layer is serrated in coordination with the array of louvres so as to deflect received sunlight away from the eye-box of the head-up display.
1. A head-up display for a vehicle, the head-up display being configured to display images to a viewer having an eye in an eye-box, wherein the head-up display comprises:
a source of spatially-modulated light;
an optical waveguide pupil expander having a partially-reflective surface and an opposing reflective surface, the optical waveguide pupil expander being configured to receive spatially-modulated light from the source of spatially-modulated light, guide the spatially-modulated light by reflection between the partially-reflective surface and the opposing reflective surface, and emit a plurality of replicas of the spatially-modulated light from a plurality of emission positions at a first portion of the partially-reflective surface, the optical waveguide pupil expander being arranged, during head-up display operation, in a configuration that is conducive to sunlight glare at one of the surfaces thereof; and
a light control layer disposed on the optical waveguide pupil expander to receive sunlight on an optical path to the reflective surface, wherein the light control layer comprises a sunlight-receiving surface and a core material separating an array of louvres,
wherein the sunlight-receiving surface of the light control layer is serrated in coordination with the array of louvres; and
wherein the array of louvres is configured to transmit spatially-modulated light of the replicas from the first portion of the partially-reflective surface of the optical waveguide pupil expander toward the eye-box, and wherein the serration provides an array of angled surfaces having an angle of orientation configured to direct sunlight received at the sunlight-receiving surface of the light control layer away from the eye-box via specular reflection.
2. The head-up display as claimed in claim 1 , wherein a periodicity of the serration of the sunlight-receiving surface is substantially equal to a periodicity of the array of louvres.
3. The head-up display as claimed in claim 2 , wherein the array of louvres is a two-dimensional array having a first and second dimension, and the serration is one-dimensional and extends in the first dimension.
4. The head-up display as claimed in claim 1 , wherein the louvres are tilted relative to a plane of the light control layer.
5. The head-up display as claimed in claim 1 , wherein the louvres are configured to absorb sunlight.
6. The head-up display as claimed in claim 1 , wherein the optical waveguide pupil expander is substantially planar.
7. The head-up display as claimed in claim 6 , wherein the optical waveguide pupil expander is arranged during head-up display operation in a substantially flat configuration relative to ground.
8. The head-up display as claimed in claim 1 , wherein the core material is substantially transmissive to image light of the head-up display.
9. The head-up display as claimed in claim 1 , wherein the sunlight-receiving surface is a coating layer that covers the core material and array of louvres.
10. The head-up display as claimed in claim 9 , wherein the coating layer is substantially transparent to image light of the head-up display.
11. The head-up display as claimed in claim 9 , wherein the coating layer is a cladding layer.
12. The head-up display as claimed in claim 1 , wherein the sunlight-receiving surface further comprises an anti-reflection coating.
13. The head-up display as claimed in claim 1 , wherein the louvres of the array of louvres are substantially parallel.
14. The head-up display as claimed in claim 1 , wherein each louvre of the array of louvres has substantially the same geometry.
15. The head-up display as claimed in claim 1 , wherein each louvre of the array of louvres is substantially rectangular or trapezoid in cross-section.
16. The head-up display as claimed in claim 1 , further comprising a windshield of a vehicle, configured such that the replicas of the spatially-modulated light are reflected by the windshield to the eye-box.
17. The head-up display as claimed in claim 1 , wherein a periodicity of the array of louvres is a uniform periodicity.