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US 6,288,805 B1Granted
Holographic projection screen and method of production
AssigneeThomson-CSF
InventorsJean-Pierre Huignard, Cécile Joubert, Jean-Claude Lehureau, Brigitte Loiseaux
Life of this patent
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Abstract
A holographic projection screen for large screen projection and back projection with a liquid crystal projector. The screen includes at least one layer made of a photosensitive material in which at least one index grating may be recorded by an interference of an optical recording wave with an optical object wave. The thickness of the layer is equal to or greater than n0Λ2/2π, where n0 is the average index of the photosensitive material, Λ is the average spacing of the index grating and λ is the recording wavelength.
Claims17
A holographic screen, comprising:
- at least one photosensitive layer having at least one index grating recorded by interference between a recording wave having a first angle of incidence with respect to a plane of said at least one photosensitive layer, and a scattered object wave having a second angle of incidence with respect to the plane of said at least one photosensitive layer and being formed by transmitting a plane wave through a scattering grating;
- and
- a light-absorbing layer disposed on a back surface of said at least one photosensitive layer, said back surface being opposite to a front surface on which an image is to be formed,
- wherein a thickness (t) of said at least one photosensitive layer is defined by:
- (t≧(n0Λ2)/(2πλ))
- where n0 is an average index of said at least one photosensitive layer;
- Λ is an average spacing of the at least one index grating;
- and
- λ is a wavelength of the recording wave,
- wherein a combination of the at least one photosensitive layer and the light-absorbing layer are configured to absorb light which is not incident on the at least one photosensitive layer at the first angle of incidence of the recording wave, and
- wherein light incident on the at least one photosensitive layer at the first angle of incidence is reflected.
8 more elements
A method for producing a holographic screen, comprising:
- first illuminating at least one photosensitive layer with a scattered object wave having a first angle of incidence with respect to a plane of said at least one photosensitive layer, said scattered object wave being formed by transmitting a plane wave through a scattering grating, and said at least one photosensitive layer having a thickness (t) defined by the following equation:
- (t≧(n0Λ2)/(2πλ))
- where n0 is an average index of said at least one photosensitive layer,
- Λ is an average spacing of the at least one index grating, and
- λ is a wavelength of the recording wave;
- second illuminating said at least one photosensitive layer with a recording wave having a second angle of incidence with respect to said plane of said at least one photosensitive layer while performing said first illuminating step;
- and
- after recording and development of the photosensitive layer applying a light-absorbing layer to a back surface of said at least one photosensitive layer, said back surface being opposite to a front surface on which an image is to be formed,
- wherein a combination of the at least one photosensitive layer and the light-absorbing layer are configured to absorb light which is not incident on the at least one photosensitive layer at the second angle of incidence of the recording wave, and
- wherein light incident on the at least one photosensitive layer at the second angle of incidence is reflected.
7 more elements
A holographic screen, comprising:
- at least one photosensitive layer having at least one index grating formed by the step of interfering a recording wave having a first angle of incidence with respect to a plane of said at least one photosensitive layer, and a scattered object wave having a second angle of incidence with respect to the plane of said at least one photosensitive layer and being formed by transmitting a plane wave through a scattering grating;
- and
- a light-absorbing layer disposed on a back surface of said at least one photosensitive layer, said back surface being opposite to a front surface on which an image is to be formed,
- wherein a thickness (t) of said at least one photosensitive layer is defined by:
- (t≧(n0Λ2)/(2πλ))
- where n0 is an average index of said at least one photosensitive layer;
- Λ is an average spacing of the at least one index grating;
- and
- λ is a wavelength of the recording wave,
- wherein a combination of the at least one photosensitive layer and the light-absorbing layer are configured to absorb light which is not incident on the at least one photosensitive layer at the first angle of incidence of the recording wave, and
- wherein light incident on the at least one photosensitive layer at the first angle of incidence is reflected.
8 more elements
A holographic screen, comprising;
- at least one photosensitive layer recorded by interference between a recording wave having a first angle of incidence with respect to a plane of said at least one photosensitive layer, and a scattered object wave having a second angle of incidence with respect to the plane of said at least one photosensitive layer and being formed by transmitting a plane wave through a scattering grating;
- and
- a light-absorbing layer disposed on a back surface of said at least one photosensitive layer, said back surface being opposite to a front surface on which an image is to be formed,
- wherein said at least one photosensitive layer is photosensitive to a range of wavelengths comprising three primary color wavelengths, λ being an average wavelength of said range of wavelengths, and
- wherein a thickness (t) of said at least one photosensitive layer is defined by:
- (t≧(n0Λ2)/(2πλ))
- where n0 is an average index of said at least one photosensitive layer;
- Λ is an average spacing of the at least one index grating;
- and
- λ is a wavelength of the recording wave,
- wherein a combination of the at least one photosensitive layer and the light-absorbing layer are configured to absorb light which is not incident on the at least one photosensitive layer at the first angle of incidence of the recording wave, and
- wherein light incident on the at least one photosensitive layer at the first angle of incidence is reflected.
9 more elements
Dependencies are inferred from the claim text.