Light control device
A head-up display is provided. The head-up display comprises an optical component comprising a surface arranged, during head-up display operation, in a configuration that is conducive to sunlight glare. The head-up display further comprises a reflection suppression device arranged to receive sunlight on an optical path to the surface. The reflection suppression device comprises a lattice structure. The lattice structure extends in a first direction and a second direction. The lattice structure forms a plurality of channels extending in a third direction. Each channel is defined by a respective axis having a first angle in the first direction and second angle in the second direction. The first angle is a function of the first direction.
1 . A method of head-up display in a vehicle, the method comprising:
displaying a hologram of an image on a spatial light modulator;
illuminating the hologram displayed on the spatial light modulator to form spatially modulated light encoded with the hologram;
propagating the spatially modulated light to a scattering diffuser disposed at an image reconstruction plane of the hologram to provide a reconstructed image on the diffuser and provide the reconstructed image as an output of the scattering diffuser;
coupling the output of the scattering diffuser into an input port of a planar waveguide pupil expander;
replicating the reconstructed image to form an array of replicas of the reconstructed image, the array having a first direction and a second direction;
transmitting the array of replicas of the reconstructed image through a plurality of tilted channels of a reflection suppression device disposed on top of the planar waveguide pupil expander, wherein each tilted channel of the plurality of channels is tilted from vertical by a first angle in the first direction of the array of replicas and tilted from vertical by a second angle in the second direction of the array of replicas, wherein the first angle of the tilted channels increases with distance in the first direction;
relaying the plurality of replicas of the reconstructed image to an eye-box of the head-up display using a windscreen of the vehicle; and
simultaneously with the transmitting, blocking sunlight on an optical path to the eye-box via the planar waveguide pupil expander using walls of the tilted channels.
2 . The method of claim 1 wherein the first angle increases with distance in the first direction from being in the range 15 to 35 degrees on a first side to being in the range 25 to 45 degrees on a second the other side.
3 . The method of claim 1 , wherein the first angle increases with distance in the first direction from a value on a first side to a value on a second side that is at least 3 degrees greater than the value on the first side.
4 . The method of claim 3 , wherein the second angle increases with distance in the second direction.
5 . The method of claim 4 wherein the second angle increases with distance in the second direction from being in the range 5 to 15 degrees on a first side to 15 to 30 degrees on a second the other side.
6 . The method of claim 4 , wherein the second angle increases with distance in the second direction from a value on a first side to a value on a second side that is at least 5 degrees greater than the value on the first side.
7 . The method of claim 3 , wherein the first direction corresponds to a horizontal dimension of the image and the second direction corresponds to a vertical direction of the image.
8 . The method of claim 3 , wherein the first direction is at an angle of 20 to 35 degrees to a horizontal dimension of the image, after relaying using the windscreen, and the second direction corresponds to a vertical direction of the image.
9 . The method of claim 3 , wherein at least one of the tilted channels is substantially parallel to a gut ray of the image.
10 . The method of claim 3 , wherein the tilted channels have the same size and/or shape.
11 . The method of claim 3 , wherein the tilted channels of the reflection suppression device are provided in a plurality of rows of channels, in which channels of each row are offset from channels of a neighboring row.
12 . The method of claim 3 , wherein the reflection suppression device is curved about a first axis parallel to its plane.
13 . The method of claim 1 , wherein the first angle increases with distance in the first direction from a value on a first side to a value on a second side that is at least 5 degrees greater than the value on the first side.
14 . The method of claim 1 , wherein the first angle increases with distance in the first direction from a value on a first side to a value on a second side that is at least 10 degrees greater than the value on the first side.
15 . The method of claim 1 , wherein the second angle increases with distance in the second direction from a value on a first side to a value on a second side that is at least 5 degrees greater than the value on the first side.
16 . The method of claim 1 , wherein the first direction is at an angle of 20 to 35 degrees to a horizontal dimension of the image, after relaying using the windscreen, and the second direction corresponds to a vertical direction of the image.
17 . The method of claim 1 , wherein at least one of the tilted channels is substantially parallel to a gut ray of the image.
18 . The method of claim 1 , wherein the tilted channels of the reflection suppression device are provided in a plurality of rows of channels, in which channels of each row are offset from channels of a neighboring row.
19 . A head-up display for a vehicle, the head-up comprising:
a spatial light modulator arranged to display a hologram of an image;
a light source arranged to illuminate the hologram displayed on the spatial light modulator to form spatially modulated light encoded with the hologram;
a diffuser disposed at an image reconstruction plane of the hologram and arranged to receive the spatially modulated such that a reconstructed image is formed thereon;
a planar waveguide pupil expander comprising:
an input port arranged to receive the reconstructed image from the diffuser; and
a pair of opposing reflective surfaces arranged to waveguide the reconstructed image therebetween by internal reflection to form a plurality of replicas of the reconstructed image for transmission to a viewing window, wherein a first surface of the pair of opposing reflective surfaces is partially transmissive thereby forming an output port for a plurality of replicas of the reconstructed image;
wherein the first surface is arranged, during operation of the head-up display, on an optical path of sunlight from the planar waveguide pupil expander to the viewing window; and
a reflection suppression device arranged on the optical path of the sunlight to the first surface of the planar waveguide pupil expander, the reflection suppression device comprising a plurality of tilted channels, wherein each tilted channel of the plurality of channels is tilted from vertical by a first angle in a first direction of the array of replicas and tilted from vertical by a second angle in a second direction of the array of replicas, wherein the first angle of the tilted channels increases with distance in the first direction.
20 . The head-up display of claim 19 , wherein the first angle increases with distance in the first direction from being in the range 15 to 35 degrees on a first side to that is in the range 25 to 45 degrees on a second side.
21 . The head-up display of claim 19 , wherein the first angle increases with distance in the first direction from a value on a first side to a value on a second side that is at least 5 degrees greater than the value on the first side.
22 . The head-up display of claim 21 , wherein the second angle increases with distance in the second direction.
23 . The head-up display of claim 22 wherein the second angle increases with distance in the second direction from being in the range 5 to 15 degrees on a first side to 15 to 30 degrees on a second.
24 . The head-up display of claim 22 , wherein the second angle increases with distance in the second direction from a value on a first side to a value on a second the other side being at least 3 degrees greater than the value on the first side.
25 . The head-up display of claim 21 , wherein the first direction corresponds to a horizontal dimension of the image and the second direction corresponds to a vertical direction of the image.
26 . The head-up display of claim 21 , wherein the first direction is at an angle of 20 to 35 degrees to a horizontal dimension of the image, after relaying using a windscreen, and the second direction corresponds to a vertical direction of the image.
27 . The head-up display of claim 21 , wherein at least one of the tilted channels is substantially parallel to a gut ray of the image.
28 . The head-up display of claim 21 , wherein the tilted channels have the same size and/or shape.
29 . The head-up display of claim 21 , wherein the tilted channels of the reflection suppression device are provided in a plurality of rows of channels, in which channels of each row are offset from channels of a neighboring row.
30 . The head-up display of claim 21 , wherein the reflection suppression device is curved about a first axis parallel to its plane.