Phase gratings with odd symmetry for high-resolution lensed and lensless optical sensing
AssigneeRambus Inc.
InventorsPatrick R. Gill, David Geoffrey Stork
Life of this patent
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Abstract
A sensing device with an odd-symmetry grating projects near-field spatial modulations onto a closely spaced photodetector array. Due to physical properties of the grating, the spatial modulations are in focus for a range of wavelengths and spacings. The spatial modulations are captured by the array, and photographs and other image information can be extracted from the resultant data. Used in conjunction with a converging optical element, versions of these gratings provide depth information about objects in an imaged scene. This depth information can be computationally extracted to obtain a depth map of the scene.
Claims16
A camera for sensing incident light over a wavelength band of interest, the camera comprising:
- a photodetector array in a path of the incident light;
- and
- a phase grating overlying the photodetector array and disposed in the path to illuminate a pattern area at the photodetector array, the phase grating including:
- curved boundaries of odd symmetry, intersecting to form a spiral, separating stepped features on opposite sides of each boundary, the stepped features on the opposite sides of each boundary offset from the array by one half of one of the wavelengths of the wavelength band of interest, plus an integer number of the one of the wavelengths, to produce curtains of destructive interference that extend to the photodetector array.
A camera for sensing incident light over a wavelength band of interest, the camera comprising:
- a photodetector array in a path of the incident light;
- and
- a phase grating overlying the photodetector array and disposed in the path to illuminate a pattern area at the photodetector array, the phase grating including:
- curved boundaries of odd symmetry separating stepped features on opposite sides of each boundary, the stepped features on the opposite sides of each boundary offset from the array by one half of one of the wavelengths of the wavelength band of interest, plus an integer number of the one of the wavelengths, to produce curtains of destructive interference that pattern spiral point spread functions on the photodetector array.
Dependencies are inferred from the claim text.