Light Projection System Angular Spatial Modulation
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Solution Overview
Problem
Conventional 3D display technologies require doubling the Degrees of Freedom (DOF) to project two images for each eye, limiting the information bandwidth and resolution, and existing methods for angular and spatial light modulation are not efficient for creating high-resolution, multi-directional images.
Innovation Solution
A light projection system that combines a spatial light modulator and an angular light modulator, controlled by a processor to form and direct computer-generated holograms, allowing for selective angular and spatial modulation of light beams, enabling the projection of images in different directions using a digital micromirror device (DMD) and other actuatable elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two images are projected simultaneously for 3D display using conventional methods, then the 3D effect is achieved, but the Degrees of Freedom (DOF) must be doubled, limiting information bandwidth and resolution
Solution Approach 1:
The patent transitions from projecting two separate 2D images (requiring doubled DOF) to projecting a single computer-generated hologram that encodes 3D information in the angular dimension. The hologram uses diffraction patterns to create multiple virtual images at different angles, effectively adding an angular dimension to the display space without increasing pixel count.
Solution Approach 2:
The system changes the modulation parameters from spatial-only control (conventional SLM) to combined angular and spatial control. By controlling both the phase/amplitude distribution across the hologram and the angular direction of projection, the system achieves 3D display with the same physical pixel array, avoiding the need to double DOF.
2Measurement precision
If conventional SLMs are used for spatial light modulation, then image projection is achieved, but angular modulation capability is limited
Solution Approach 1:
The patent makes the SLM perform multiple functions: it acts as both a spatial light modulator (controlling amplitude/phase distribution for image formation) and an angular light modulator (controlling diffraction patterns for angular direction control). This dual functionality is achieved through computer-generated hologram techniques that encode both spatial and angular information in the same modulated wavefront.
3Loss of information
If pixel density of SLM is increased to improve resolution, then information bandwidth increases, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of increasing spatial pixel density to improve information bandwidth, the patent utilizes the angular dimension through holographic diffraction. A single pixel can contribute to multiple angular directions through diffraction patterns, effectively increasing the information capacity without increasing the physical number of pixels or their density.
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
This system enhances the resolution and information bandwidth by allowing multiple images to be projected in various directions, improving the 3D display experience with increased angular and spatial modulation capabilities, effectively addressing the limitations of conventional 3D technologies.
Implementation Method 1
control the light modulator to form a computer generated hologram (CGH) wavefront from the light modulator which corresponds to an image to be produced in a far field
Implementation Method 2
control the light modulator to form a computer generated hologram (CGH) wavefront
Implementation Method 3
selectively direct the CGH wavefront in a direction
Data Source
AI summary
A light projection system comprising a light modulator that comprises a plurality of pixels each capable of selectively directing a corresponding modulatable amount of light, and a processor coupled to the light modulator to control the amount of light output from each of the plurality of pixels. The processor is configured to control the light modulator to form a computer generated hologram (CGH) wavefront from the light modulator corresponding to an image to be produced in the far field. The processor is also configured to control the light modulator to selectively direct the CGH wavefront. The light modulator may comprise an angular light modulator (ALM) comprising the plurality of pixels, each of the plurality of pixels having an OFF state and an ON state, the ALM arranged to direct the amounts of light in the direction as the pixels transition between the ON state and the OFF state.