Display apparatus
First Claim
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1. A display apparatus, comprising:
- a display unit for emitting light;
a first diffraction grating for causing light from said display unit to be diffracted; and
a second diffraction grating for causing the light diffracted by said first diffraction grating to be diffracted and directing it toward a pupil of an observer,wherein said apparatus satisfies the following condition;
##EQU2## where l1 is a distance between said display unit and said first diffraction grating, l2 is a distance between said first diffraction grating and said second diffraction grating, P1 is a grating pitch of said first diffraction grating, P2 is a grating pitch of said second diffraction grating, θ
1 is an incident angle of the light on said first diffraction grating, θ
2 is an exit angle of the light from said first diffraction grating, and θ
3 is an incident angle of the light on said second diffraction grating.
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Abstract
a display apparatus comprises, a display unit, a first diffraction grating for diffracting the light from the display unit, and a second diffraction grating for diffracting the diffracted light from the first diffraction grating, the apparatus being constructed in such a manner that the optical path length between the display unit and the first diffraction grating is shorter than that between the first and second diffraction gratings.
114 Citations
17 Claims
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1. A display apparatus, comprising:
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a display unit for emitting light; a first diffraction grating for causing light from said display unit to be diffracted; and a second diffraction grating for causing the light diffracted by said first diffraction grating to be diffracted and directing it toward a pupil of an observer, wherein said apparatus satisfies the following condition;
##EQU2## where l1 is a distance between said display unit and said first diffraction grating, l2 is a distance between said first diffraction grating and said second diffraction grating, P1 is a grating pitch of said first diffraction grating, P2 is a grating pitch of said second diffraction grating, θ
1 is an incident angle of the light on said first diffraction grating, θ
2 is an exit angle of the light from said first diffraction grating, and θ
3 is an incident angle of the light on said second diffraction grating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A headup display apparatus, comprising:
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a display unit for emitting light; a first diffraction grating for causing light from said display unit to be diffracted; and a beam combiner having a second diffraction grating for causing the light diffracted by said first diffraction grating to be reflectively diffracted and directing it toward a pupil of an observer; wherein said apparatus satisfies the following condition, ##EQU3##
space="preserve" listing-type="equation">P.sub.1 =λ
.sub.0 | sin θ
.sub.1 -sin θ
hd 2|
space="preserve" listing-type="equation">P.sub.2 =λ
.sub.0 | sin θ
.sub.4 -sin θ
.sub.3 |where λ
1 is a distance between said display unit and said first diffraction grating, λ
2 is a distance between said first diffraction grating and said second diffraction grating, P1 is a grating pitch of said first diffraction grating, P2 is a grating pitch of said second diffraction grating, θ
1 is an incident angle of the light on said first diffraction grating, θ
2 is an exit angle of the light from said first diffraction grating, θ
3 is an incident angle of the light on said second diffraction grating, θ
4 is an exit angle of the light from said second diffraction grating and λ
0 is the central wave length of the light. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification
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Current AssigneeCanon Kabushiki Kaisha (Canon Inc.)
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Original AssigneeCanon Kabushiki Kaisha (Canon Inc.)
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InventorsKuwayama, Tetsuro, Kushibiki, Nobuo, Taniguchi, Naosato, Yoshinaga, Yoko
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Primary Examiner(s)Arnold, Bruce Y.
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Assistant Examiner(s)RYAN, JAY
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Application NumberUS07/355,347Time in Patent Office798 DaysField of Search350/3.61, 350/3.7, 350/3.72, 350/162.17, 350/162.18, 350/162.2, 350/162.23, 350/171, 350/174US Class Current359/13CPC Class CodesG02B 27/0103 comprising holographic elem...
