Diffractive Optic Device for Holographic Projection
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Solution Overview
Problem
Existing diffractive optic elements for holographic projections suffer from chromatic aberrations and reduced efficiency across multiple wavelengths, limiting their effectiveness in producing high-quality, full-color holographic images.
Innovation Solution
A diffractive optic device with a planar lens comprising a patterned material with varying cell heights, optimized for broadband performance, which can convey holograms across multiple wavelengths without the need for specific filtered light, and can be embedded in objects like currency notes or credit cards, using a filling material with a different refractive index to enhance image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If binary-phase diffractive optics are used to ease fabrication, then manufacturing simplicity is improved, but chromatic aberrations worsen
Solution Approach 1:
The patent transitions from binary-phase (two-level) diffractive optics to multi-level diffractive optics with continuous phase variation. By changing the parameter of phase depth from discrete two levels to continuous multiple levels, the system achieves broadband operation while maintaining fabrication feasibility through grayscale lithography or embossing processes.
Solution Approach 2:
The patent employs composite material structures combining the diffractive optic element with a substrate and optional filling materials. This composite approach allows the diffractive layer to provide phase modulation while the substrate and filling materials provide structural support and optical compensation, enabling chromatic aberration correction without complicating the primary diffractive structure.
2Manufacturing precision
If diffractive optics are designed for single-wavelength optimization, then performance at that wavelength is improved, but efficiency and image contrast at other wavelengths deteriorate
Solution Approach 1:
The patent designs a universal diffractive optic element that performs the holographic function across multiple wavelengths simultaneously. By incorporating continuous phase variation and optimizing for broadband operation, the single element serves multiple wavelength requirements, eliminating the need for separate wavelength-specific optical elements.
Solution Approach 2:
The patent optimizes the phase depth distribution and cell height parameters across multiple levels to achieve constructive interference for holographic images at various wavelengths. By adjusting these parameters to create a continuous phase profile, the system maintains high diffraction efficiency and image contrast across a broad spectral range rather than being optimized for a single wavelength.
3Reliability
If conventional lens systems are used, then imaging capability is provided, but the number of elements and material complexity increases
Solution Approach 1:
The patent merges multiple optical functions (diffraction, phase modulation, focusing, and chromatic aberration correction) into a single integrated diffractive optic element. This consolidation eliminates the need for separate lens elements and aberration correction components that would traditionally be required in conventional optical systems.
Solution Approach 2:
The patent replaces conventional refractive lens systems with a diffractive optical element that uses interference and diffraction phenomena to achieve the same imaging functions. This substitution reduces the number of mechanical optical components while maintaining or improving imaging capability through wave-based optical manipulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-efficiency, full-color holographic image projections with minimal absorption losses, capable of forming 2D or 3D images across a broad spectrum, reducing material usage and thickness in imaging systems while maintaining high transmission and reflection efficiencies.
Implementation Method 1
Diffractive optic elements are typically thin phase elements that operate by means of interference and diffraction to produce arbitrary distributions of light
Implementation Method 2
Diffractive optic elements are typically thin phase elements that operate by means of interference and diffraction to produce arbitrary distributions of light
Implementation Method 3
The filling material has a refractive index different from the patterned material
Data Source
AI summary
Technology is described for methods and systems for a diffractive optic device (525) for holographic projection. The diffractive optic device can include a lens (535) configured to convey a hologram. The lens (535) further comprises a patterned material (510) formed with an array of cells having a non-planar arrangement of cell heights extending from a surface of the patterned material. The lens further optionally comprises a filling material (530) to fill gaps on both surfaces of the patterned material.