LIGHT CONTROL DEVICE

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 such that an image reconstruction of the image is output by the diffuser;

coupling the output of the scattering diffuser into an input port of a waveguide pupil expansion system comprising a planar waveguide pupil expander;

replicating the image in a first direction and second direction to form an array of replicas of the image;

transmitting the array of replicas of the image through a plurality of tilted channels in a lattice structure of a reflection suppression device, wherein the lattice structure comprises a plurality of lattice elements extending from the surface of the planar waveguide pupil expander, at least one lattice element having a first pair of opposing parallel first sides and a second pair of opposing parallel second sides, the first sides being longer than the second sides;

relaying the plurality of replicas of the image to an eye-box of the head-up display using the windscreen of the vehicle and/or a diffractive light-turning component; and

simultaneously with the transmitting, blocking sunlight on an optical path to the eye-box via the waveguide pupil expander using walls of the tilted channels and/or blocking zeroth-order light from the diffractive light-turning component using walls of the tilted channels.

2 . The method of head-up display as claimed in claim 1 , wherein an aspect ratio of at least one of the lattice elements is substantially equal to or greater than an aspect ratio of an image to be displayed.

3 . The method of head-up display as claimed in claim 1 , wherein the head-up display has a field of view defined by a first dimension and second dimension, the first dimension being greater than the second dimension, and wherein the first sides of at least one of the lattice elements of the reflection suppression device extend in a first direction corresponding to the first dimension.

4 . The method of head-up display as claimed in claim 3 , wherein the first direction is at an angle relative to the first dimension in the range of 0° to 45°.

5 . The method of head-up display as claimed in claim 3 , wherein the first direction is substantially parallel to the first dimension.

6 . The method of head-up display as claimed in claim 1 , wherein at least one of the lattice elements further comprises a third pair of opposing parallel third sides, the third sides being substantially the same length as the second sides.

7 . The method of head-up display as claimed in claim 6 , wherein each second side is arranged at an angle relative to the respective third side, the angle being in the range of 60° to 180°.

8 . The method of head-up display as claimed in claim 6 , wherein at least one of the lattice elements has an elongated hexagonal shape.

9 . The method of head-up display as claimed in claim 1 , wherein each first side is arranged substantially perpendicularly to each adjacent second side.

10 . The method of head-up display as claimed in claim 9 , wherein at least one of the lattice elements is substantially rectangular in shape.

11 . The method of head-up display as claimed in claim 1 , wherein at least one lattice element extends from the surface of the optical component in a direction substantially parallel to a guy ray emitted from the surface.

12 . The method of head-up display as claimed in claim 1 , wherein the lattice elements extend away from the surface of the optical component at a first angle in the range of 0° to 65°.

13 . The method of head-up display as claimed in claim 12 , wherein the lattice elements extend away from the surface of the optical component at a second angle in the range of 0° to 25°, the second angle taken in a perpendicular direction than the first angle.

14 . The method of head-up display as claimed in claim 1 , wherein a ratio of the length of the first sides compared to the length of the second sides is in the range of 2:1 to 50:1.

15 . The method of head-up display as claimed in claim 1 , wherein each lattice element has substantially the same shape and/or size.

16 . The method of head-up display as claimed in claim 1 , wherein a first periodicity of the first sides is higher than a second periodicity of the second sides.

17 . The method of head-up display as claimed in claim 1 , wherein the lattice structure comprises a first curvature about a first axis parallel to the surface of the reflection suppression device.

18 . The method of head-up display as claimed in claim 17 , wherein the first curvature is such that each first side is arranged at a different angle relative to a plane of the surface of the optical component compared to the neighbouring first sides.

19 . The method of head-up display as claimed in claim 17 , wherein the lattice structure is parallel to a second axis, the second axis being parallel to the surface of the optical component and perpendicular to the first axis.

20 . The method of head-up display as claimed in claim 17 , wherein the lattice structure comprises a second curvature about a second axis parallel to the surface of the optical component and perpendicular to the first axis.

21 . The method of head-up display as claimed in claim 17 , wherein the curvature of the lattice structure corresponds to the change in angle at which light is emitted from across the surface of the optical component.

22 . The method of head-up display as claimed in claim 17 , wherein the curvature of the lattice structure corresponds to the curvature of an optical combiner arranged downstream from the reflection suppression device on an optical path from the optical component to the viewing window.

23 . The method of head-up display as claimed in claim 1 , wherein the reflection suppression device has a first end and is arranged such that lateral movement relative to the surface of the optical component is restricted and such that the reflection suppression device can rotate relative to the surface about the first end.

24 . The method of head-up display as claimed in claim 1 , wherein each of the first sides have a first end and a second end, and wherein a plurality of the first sides have an upper section, a lower section and a central section extending between the first end and the second end, the central section being arranged between the upper and lower sections and the central section having the combined width of the upper and lower sections.

25 . 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 such that an image reconstruction of the image is formed thereon;

a waveguide pupil expansion system comprising:

an input port arranged to receive the image reconstructed on the diffuser; and

a pair of opposing reflective surfaces arranged to waveguide the image therebetween by internal reflection to form a plurality of replicas of the image for transmission to the viewing window, wherein a surface of the pair of opposing reflective surfaces is partially transmissive thereby forming an output port for a plurality of replicas of the image;

wherein the first surface is arranged, during operation of the head-up display, on an optical path of sunlight from the waveguide to the viewing window; and

a reflection suppression device arranged on the optical path of the sunlight to the first surface, the reflection suppression device comprising a lattice structure having a plurality of tilted channels, wherein the lattice structure comprises a plurality of lattice elements extending from the first surface, at least one lattice element having a first pair of opposing parallel first sides and a second pair of opposing parallel second sides, the first sides being longer than the second sides.