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US 12,596,264 B2Granted
Display apparatus
AssigneeShenzhen Optiave Display Technologies Co., Ltd.
InventorsLiangfu Zhu, Yisheng Zhu, Tapani Kalervo Levola
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Abstract
A display apparatus includes an optical engine and a stack of expander devices. The optical engine forms input light which comprises a plurality of input light beams representing an input image. The stack of expander devices forms output light by diffractively expanding the input light. The output light includes a plurality of output light beams representing the input image. The stack includes a first expander device and a second expander device. The grating period of each diffractive element of the first expander device is equal to the grating period of a corresponding diffractive element of the second expander device.
Claims18
A display apparatus, comprising:
- an optical engine to form input light, which comprises a plurality of input light beams representing an input image;
- and
- a stack of expander devices to form output light by diffractively expanding the input light, wherein the output light comprises a plurality of output light beams representing said input image,
- wherein the stack comprises a first expander device and a second expander device,
- wherein the first expander device comprises a first group of diffractive elements, which contribute to the direction of the output light beams,
- wherein the second expander device comprises a second group of diffractive elements, which contribute to the direction of the output light beams,
- wherein the first expander device comprises a first in-coupling element to diffract the input light into a waveguiding plate of the first expander device,
- wherein the first expander device is arranged to transmit a part of the input light to the second expander device,
- wherein the second expander device comprises a second in-coupling element to diffract the transmitted part of the input light into a waveguiding plate of the second expander device,
- wherein the grating period of each element of the first group is equal to the grating period of a corresponding element of the second group,
- wherein a refractive index of the first in-coupling element is different from a refractive index of the second in-coupling element.
8 more elements
A method for displaying an image by using a display apparatus, the display apparatus comprising:
- an optical engine to form input light, which comprises a plurality of input light beams representing an input image;
- and
- a stack of expander devices to form output light by diffractively expanding the input light, wherein the output light comprises a plurality of output light beams representing said input image,
- wherein the stack comprises a first expander device and a second expander device,
- wherein the first expander device comprises a first group of diffractive elements, which contribute to the direction of the output light beams,
- wherein the second expander device comprises a second group of diffractive elements, which contribute to the direction of the output light beams,
- wherein the first expander device comprises a first in-coupling element to diffract the input light into a waveguiding plate of the first expander device,
- wherein the first expander device is arranged to transmit a part of the input light to the second expander device,
- wherein the second expander device comprises a second in-coupling element to diffract the transmitted part of the input light into a waveguiding plate of the second expander device,
- wherein the grating period of each element of the first group is equal to the grating period of a corresponding element of the second group,
- wherein a refractive index of the first in-coupling element is different from a refractive index of the second in-coupling element,
- the method comprising:
- forming the input light, which comprises light beams corresponding to points of the input image,
- forming the output light by using the stack to diffractively expand the input light.
11 more elements
A display apparatus, comprising:
- an optical engine to form input light, which comprises a plurality of input light beams representing an input image;
- and
- a stack of expander devices to form output light by diffractively expanding the input light, wherein the output light comprises a plurality of output light beams representing said input image,
- wherein the stack comprises a first expander device and a second expander device,
- wherein the first expander device comprises a first group of diffractive elements, which contribute to the direction of the output light beams,
- wherein the second expander device comprises a second group of diffractive elements, which contribute to the direction of the output light beams,
- wherein the first expander device comprises a first in-coupling element to diffract the input light into a waveguiding plate of the first expander device,
- wherein the first expander device is arranged to transmit a part of the input light to the second expander device,
- wherein the second expander device comprises a second in-coupling element to diffract the transmitted part of the input light into a waveguiding plate of the second expander device,
- wherein the grating period of each element of the first group is equal to the grating period of a corresponding element of the second group,
- wherein a thickness of the waveguiding plate of the first expander device is different from a thickness of the waveguiding plate of the second expander device.
8 more elements
Dependencies are inferred from the claim text.