DIFFRACTIVE BEAM EXPANDER AND A VIRTUAL DISPLAY BASED ON A DIFFRACTIVE BEAM EXPANDER
First Claim
1. A device comprising:
- a substantially planar waveguiding substrate;
an input grating to provide an in-coupled beam propagating within said substrate by diffracting light of an input beam into said substrate;
a first deflecting grating portion to provide a first deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said first deflected beam and the azimuth angle of said in-coupled beam is negative, said first deflecting grating portion comprising substantially linear diffractive features;
a second deflecting grating portion to provide a second deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said second deflected beam and the azimuth angle of said in-coupled beam is positive, said second deflecting grating portion comprising substantially linear diffractive features, the diffractive features of said second deflecting grating portion having a different orientation than the diffractive features of said first deflecting grating portion;
a first restoring grating portion to provide a first restored beam by diffracting light of said first deflected beam;
a second restoring grating portion to provide a second restored beam, said second restored beam being substantially parallel to said first restored beam; and
an output grating to provide an out-coupled beam by diffracting light of said first restored beam and said second restored beam out of said substrate, said output beam being substantially parallel to said input beam.
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0 Petitions
Accused Products
Abstract
A diffractive beam expander (50) comprises a substantially planar waveguiding substrate, an input grating (10) to provide an in-coupled beam (B1) propagating within said substrate, and an output grating (30) to provide an out-coupled beam. The expander (50) comprises also four or more further grating portions to expand the height of the in-coupled beam (B1). A part of the in-coupled light is diffracted by a first deflecting grating portion (21 a) to provide a first deflected beam. A part of the in-coupled light is diffracted by a second deflecting grating portion (22a) to provide a second deflected beam. The first deflected beam propagates downwards and the second deflected beam propagates upwards with respect to the in-coupled beam (B1). The first deflected beam impinges on a first direction-restoring grating portion (21 b) and the second deflected beam impinges on a second direction-restoring grating portion (22b). The first restoring grating portion (21 b) provides a first restored beam (V1) and the second restoring grating portion (22b) provides a second restored beam (V2), which both have the same direction as the in-coupled beam (B1). Out-coupling provides an output beam which is parallel to the input beam, and has a greater vertical dimension than said input beam.
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Citations
15 Claims
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1. A device comprising:
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a substantially planar waveguiding substrate; an input grating to provide an in-coupled beam propagating within said substrate by diffracting light of an input beam into said substrate; a first deflecting grating portion to provide a first deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said first deflected beam and the azimuth angle of said in-coupled beam is negative, said first deflecting grating portion comprising substantially linear diffractive features; a second deflecting grating portion to provide a second deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said second deflected beam and the azimuth angle of said in-coupled beam is positive, said second deflecting grating portion comprising substantially linear diffractive features, the diffractive features of said second deflecting grating portion having a different orientation than the diffractive features of said first deflecting grating portion; a first restoring grating portion to provide a first restored beam by diffracting light of said first deflected beam; a second restoring grating portion to provide a second restored beam, said second restored beam being substantially parallel to said first restored beam; and an output grating to provide an out-coupled beam by diffracting light of said first restored beam and said second restored beam out of said substrate, said output beam being substantially parallel to said input beam. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for expanding a light beam comprising:
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diffracting light of an input beam into a substantially planar waveguiding substrate in order to provide an in-coupled beam propagating within said substrate; providing a first deflected beam by diffracting a part of said in-coupled beam by using a first deflecting grating portion such that the difference between the azimuth angle of said first deflected beam and the azimuth angle of said in-coupled beam is negative; providing a second deflected beam by diffracting a part of said in-coupled beam by using a second deflecting grating portion such that the difference between the azimuth angle of said second deflected beam and the azimuth angle of said in-coupled beam is positive; providing a first restored beam by diffracting a part of said first deflected beam by using a first restoring grating portion; providing a second restored beam by diffracting a part of said second deflected beam by using a second restoring grating portion, said second restored beam being substantially parallel to said first restored beam; and coupling light of said first restored beam and said second restored beam out of said substrate to provide an output beam, said output beam being substantially parallel to said input beam; wherein said first deflecting grating portion comprises substantially linear diffractive features, and said second deflecting grating portion comprising substantially linear diffractive features, the diffractive features of said second deflecting grating portion having a different orientation than the diffractive features of said first deflecting grating portion. - View Dependent Claims (9)
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10. A device comprising an optical engine to provide at least one light beam, and a diffractive beam expander to expand said at least one light beam such that a virtual image is observable through a viewing aperture of said diffractive beam expander, said diffractive beam expander in turn comprising:
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a substantially planar waveguiding substrate, an input grating to provide an in-coupled beam propagating within said substrate by diffracting light of an input beam into said substrate; a first deflecting grating portion to provide a first deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said first deflected beam and the azimuth angle of said in-coupled beam is negative, said first deflecting grating portion comprising substantially linear diffractive features; a second deflecting grating portion to provide a second deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said second deflected beam and the azimuth angle of said in-coupled beam is positive, said second deflecting grating portion comprising substantially linear diffractive features, the diffractive features of said second deflecting grating portion having a different orientation than the diffractive features of said first deflecting grating portion; a first restoring grating portion to provide a first restored beam by diffracting light of said first deflected beam; a second restoring grating portion to provide a second restored beam, said second restored beam being substantially parallel to said first restored beam; and an output grating to provide an out-coupled beam by diffracting light of said first restored beam and said second restored beam out of said substrate, said output beam being substantially parallel to said input beam. - View Dependent Claims (11)
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12. A method comprising providing at least one input beam and expanding said at least one input beam such that a virtual image is observable through a viewing aperture, said expanding comprising:
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diffracting light of said input beam into a substantially planar waveguiding substrate in order to provide an in-coupled beam propagating within said substrate; providing a first deflected beam by diffracting a part of said in-coupled beam by using a first deflecting grating portion such that the difference between the azimuth angle of said first deflected beam and the azimuth angle of said in-coupled beam is negative; providing a second deflected beam by diffracting a part of said in-coupled beam by using a second deflecting grating portion such that the difference between the azimuth angle of said second deflected beam and the azimuth angle of said in-coupled beam is positive; providing a first restored beam by diffracting a part of said first deflected beam by using a first restoring grating portion; providing a second restored beam by diffracting a part of said second deflected beam by using a second restoring grating portion, said second restored beam being substantially parallel to said first restored beam; and coupling light of said first restored beam and said second restored beam out of said substrate to provide an output beam such that said output beam is substantially parallel to said input beam; wherein said first deflecting grating portion comprises substantially linear diffractive features, and said second deflecting grating portion comprises substantially linear diffractive features, the diffractive features of said second deflecting grating portion having a different orientation than the diffractive features of said first deflecting grating portion. - View Dependent Claims (13)
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14. A device comprising:
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a waveguiding means; a diffractive input means to provide an in-coupled beam propagating within said substrate by diffracting light of an input beam into said waveguiding means; a first deflecting means to provide a first deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said first deflected beam and the azimuth angle of said in-coupled beam is negative, said first deflecting means comprising substantially linear diffractive features; a second deflecting means to provide a second deflected beam by diffracting a part of said in-coupled beam such that the difference between the azimuth angle of said second deflected beam and the azimuth angle of said in-coupled beam is positive, said second deflecting means comprising substantially linear diffractive features, the diffractive features of said second deflecting grating portion having a different orientation than the diffractive features of said first deflecting means; a first restoring means to provide a first restored beam by diffracting light of said first deflected beam; a second restoring means to provide a second restored beam, said second restored beam being substantially parallel to said first restored beam; and an output means to provide an out-coupled beam by diffracting light of said first restored beam and said second restored beam out of said substrate, said output beam being substantially parallel to said input beam. - View Dependent Claims (15)
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Specification