Optical device and virtual image display device including volume hologram gratings
First Claim
Patent Images
1. An optical device comprising:
- a light guide plate receiving, for each of N types, where N is an integer of 1 or more, of wavelength bands, a plurality of parallel light beams with different incident angles each corresponding to view angles within a predetermined view angle range, each of the parallel light beams traveling in parallel, and the light guide plate guiding the received parallel light beams according to principle of total inner reflection;
a first volume hologram grating of reflection type having a diffraction configuration which includes N types of interference fringes each corresponding to the N types of wavelength bands, and diffracting and reflecting the parallel light beams which have entered the light guide plate, so as to be reflected inside the light guide plate according to the principle of total inner reflection; and
a second volume hologram grating of reflection type having a diffraction configuration which includes N types of interference fringes each corresponding to the N types of wavelength bands, and diffracting and reflecting the parallel light beams which have propagated inside the light guide plate according to the principle of total inner reflection, so as to be emitted from the light guide plate as they are in parallel, respectively, and wherein a diffraction efficiency of the second volume hologram grating is constant throughout the second volume hologram grating,wherein the optical device is configured, for a wavelength band selected from the N types of wavelength bands, to satisfy a relationship of ‘
P>
L’
, where ‘
L’
represents a central diffraction wavelength in the first and second volume hologram gratings, the central diffraction wavelength being defined for a parallel light beam corresponding to a central view angle, and ‘
P’
represents a peak wavelength of the parallel light beams which is to enter the light guide plate.
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Abstract
An optical device includes: a light guide plate receiving, for each of N types of wavelength bands, a plurality of parallel light beams with different incident angles each corresponding to view angles, and guiding the received parallel light beams; a first and a second volume hologram gratings of reflection type having a diffraction configuration which includes N types of interference fringes each corresponding to the N types of wavelength bands, and diffracting/reflecting the parallel light beams. The optical device satisfies for each wavelength band, a relationship of ‘P>L’, where ‘L’ represents a central diffraction wavelength in the first and second volume hologram gratings, defined for a parallel light beam corresponding to a central view angle, and ‘P’ represents a peak wavelength of the parallel light beams.
77 Citations
4 Claims
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1. An optical device comprising:
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a light guide plate receiving, for each of N types, where N is an integer of 1 or more, of wavelength bands, a plurality of parallel light beams with different incident angles each corresponding to view angles within a predetermined view angle range, each of the parallel light beams traveling in parallel, and the light guide plate guiding the received parallel light beams according to principle of total inner reflection; a first volume hologram grating of reflection type having a diffraction configuration which includes N types of interference fringes each corresponding to the N types of wavelength bands, and diffracting and reflecting the parallel light beams which have entered the light guide plate, so as to be reflected inside the light guide plate according to the principle of total inner reflection; and a second volume hologram grating of reflection type having a diffraction configuration which includes N types of interference fringes each corresponding to the N types of wavelength bands, and diffracting and reflecting the parallel light beams which have propagated inside the light guide plate according to the principle of total inner reflection, so as to be emitted from the light guide plate as they are in parallel, respectively, and wherein a diffraction efficiency of the second volume hologram grating is constant throughout the second volume hologram grating, wherein the optical device is configured, for a wavelength band selected from the N types of wavelength bands, to satisfy a relationship of ‘
P>
L’
, where ‘
L’
represents a central diffraction wavelength in the first and second volume hologram gratings, the central diffraction wavelength being defined for a parallel light beam corresponding to a central view angle, and ‘
P’
represents a peak wavelength of the parallel light beams which is to enter the light guide plate. - View Dependent Claims (3)
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2. A virtual image display comprising:
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an image forming section displaying an image through the use of light for N types, where N is an integer of 1 or more, of wavelength bands; a collimating optical system converting light beams for the N types of wavelength bands emitted from the image forming section into parallel light beams; a light guide plate receiving, through the collimating optical system, for each of the N types of wavelength bands, a plurality of the parallel light beams with different incident angles each corresponding to view angles within a predetermined view angle range, each of the parallel light beams traveling in parallel, and the light guide plate guiding the received parallel light beams according to principle of total inner reflection; a first volume hologram grating of reflection type having a diffraction configuration which includes N kinds of interference fringes each corresponding to the N types of wavelength bands, and diffracting and reflecting the parallel light beams which have entered the light guide plate, so as to be reflected inside the light guide plate according to the principle of total inner reflection; and a second volume hologram grating of reflection type having a diffraction configuration which includes N types of interference fringes each corresponding to the N types of wavelength bands, and diffracting and reflecting the parallel light beams which have propagated inside the light guide plate according to the principle of total inner reflection, so as to be emitted from the light guide plate as they are in parallel, respectively, and wherein a diffraction efficiency of the second volume hologram grating is constant throughout the second volume hologram grating, wherein the virtual image display is configured, for a wavelength band selected from the N types of wavelength bands, to satisfy a relationship of ‘
P>
L’
, where ‘
L’
represents a central diffraction wavelength in the first and second volume hologram gratings, the central diffraction wavelength being defined for a parallel light beam corresponding to a central view angle, and ‘
P’
represents a peak wavelength of the parallel light beams which is to enter the light guide plate. - View Dependent Claims (4)
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Specification
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Current AssigneeSony Corporation (Sony Group Corp.)
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Original AssigneeSony Corporation (Sony Group Corp.)
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InventorsAkutsu, Katsuyuki, Nakano, Satoshi, Mukawa, Hiroshi
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Primary Examiner(s)Eisen, Alexander
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Assistant Examiner(s)KIYABU, KARIN A
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Application NumberUS12/481,284Publication NumberTime in Patent Office1,274 DaysField of Search345/204US Class Current345/204CPC Class CodesG02B 2027/011 comprising device for corre...G02B 2027/0112 comprising device for gener...G02B 2027/0116 comprising devices for corr...G02B 2027/0118 comprising devices for impr...G02B 2027/0125 Field-of-view increase by w...G02B 2027/0174 holographicG02B 27/0081 with means for altering, e....G02B 27/0172 characterised by optical fe...G02B 5/203 having holographic or diffr...G02B 5/32 Holograms used as optical e...G02B 6/00 Light guides; Structural de...G02B 6/124 Geodesic lenses or integrat...G03H 1/04 Processes or apparatus for ...G03H 1/0408 Total internal reflection [...
