Method and system for beam expansion in a display device
First Claim
Patent Images
1. An optical device comprising:
- an exit surface section;
an input surface section to admit a light beam, the light beam comprising at least a first wavelength component and a second wavelength component; and
at least a first layer and a second layer, each of the first and second layers comprising a first diffractive element and a second diffractive element, such thatat least a part of the admitted light beam is diffracted in the first diffractive element in the first layer for providing a first diffracted portion;
at least a part of the admitted light beam is diffracted in the first diffractive element in the second layer for providing a second diffracted portion;
at least a part of the first diffracted portion is further diffracted in the second diffractive element in the first layer, thereby forming a first part of an exit beam exiting through the exit surface section; and
at least a part of the second diffracted portion is further diffracted in the second diffractive element in the second layer, thereby forming a second part of the exit beam exiting through the exit surface section.
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Abstract
An exit pupil extender wherein the relative amount of different color components in the exit beam is more consistent with that of the input beam. In order to compensate for the uneven amount in the diffracted color components in the exit beam, the exit pupil extender, comprises a plurality of layers having additional diffraction gratings so as to increase the amount of diffracted light for those color components with a lower amount. Additionally, color filters disposed between layers to reduce the diffracted light components with a higher amount.
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Citations
28 Claims
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1. An optical device comprising:
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an exit surface section; an input surface section to admit a light beam, the light beam comprising at least a first wavelength component and a second wavelength component; and at least a first layer and a second layer, each of the first and second layers comprising a first diffractive element and a second diffractive element, such that at least a part of the admitted light beam is diffracted in the first diffractive element in the first layer for providing a first diffracted portion; at least a part of the admitted light beam is diffracted in the first diffractive element in the second layer for providing a second diffracted portion; at least a part of the first diffracted portion is further diffracted in the second diffractive element in the first layer, thereby forming a first part of an exit beam exiting through the exit surface section; and at least a part of the second diffracted portion is further diffracted in the second diffractive element in the second layer, thereby forming a second part of the exit beam exiting through the exit surface section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of improving color uniformity in an exit beam in an optical device, the optical device having
an input surface section to admit a light beam, the light beam comprising at least a first wavelength component and a second wavelength component; - and
an exit surface section for allowing the exit beam to exit the optical device through the exit surface, said method comprising; providing at least a first layer and second layer in the optical device; providing a first diffractive element and a second diffractive element on the first layer; providing a first diffractive element and a second diffractive element on the second layer, such that at least a part of the admitted light beam is diffracted in the first diffractive element in the first layer for providing a first diffracted portion; at least a part of the admitted light beam is diffracted in the first diffractive element in the second layer for providing a second diffracted portion; at least a part of the first diffracted portion is further diffracted in the second diffractive element in the first layer, thereby forming a first part of an exit beam exiting through the exit surface section; and at least a part of the second diffracted portion is further diffracted in the second diffractive element in the second layer, thereby forming a second part of the exit beam exiting through the exit surface section, wherein the amount of the first wavelength component in the first part of the exit beam is greater than the amount of the second wavelength component in the first part of the exit beam, and the amount of the second wavelength component in the second part of the exit beam is greater than the amount of the first wavelength component in the second part of the exit beam. - View Dependent Claims (17, 18, 19, 20)
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21. A display module, comprising:
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an optical engine for receiving image data; a display device operatively connected to the optical engine for forming an image based on the image data; and an exit pupil extender, comprising; an exit surface section; an input surface section to admit a light beam, the light beam comprising at least a first wavelength component and a second wavelength component; and at least a first layer, a second layer and a third layer, each of the first, second and third layers comprises a first diffractive element and a second diffractive element, such that at least a part of the admitted light beam is diffracted in the first diffractive element in the first layer for providing a first diffracted portion; at least a part of the admitted light beam is diffracted in the first diffractive element in the second layer for providing a second diffracted portion; at least a part of the admitted light beam is diffracted in the first diffractive element in the third layer for providing a third diffracted portion; at least a part of the first diffracted portion is further diffracted in the second diffractive element in the first layer, thereby forming a first part of an exit beam exiting through the exit surface section; at least a part of the second diffracted portion is further diffracted in the second diffractive element in the second layer, thereby forming a second part of the exit beam exiting through the exit surface section; and at least a part of the third diffractive portion is further diffracted in the third diffractive element in the third layer, thereby forming a third part of the exit beam exiting through the exit surface section. - View Dependent Claims (22)
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23. An electronic device comprising:
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a data processing unit; an optical engine operatively connected to the data processing unit for receiving image data from the data processing unit; a display device operatively connected to the optical engine for forming an image based on the image data; and an exit pupil extender, comprising; an exit surface section; an input surface section to admit a light beam, the light beam comprising at least a first wavelength component and a second wavelength component; and at least a first layer, a second layer and a third layer, each of the first, second and third layers comprising a first diffractive element and a second diffractive element, such that at least a part of the admitted light beam is diffracted in the first diffractive element in the first layer for providing a first diffracted portion; at least a part of the admitted light beam is diffracted in the first diffractive element in the second layer for providing a second diffracted portion; at least a part of the admitted light beam is diffracted in the first diffractive element in the third layer for providing a third diffracted portion; at least a part of the first diffracted portion is further diffracted in the second diffractive element in the first layer, thereby forming a first part of an exit beam exiting through the exit surface section; at least a part of the second diffracted portion is further diffracted in the second diffractive element in the second layer, thereby forming a second part of the exit beam exiting through the exit surface section; and at least a part of the third diffractive portion is further diffracted in the third diffractive element in the third layer, thereby forming a third part of the exit beam exiting through the exit surface section. - View Dependent Claims (24, 25, 26, 27, 28)
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Specification