Spatial Light Modulator Multiplexing for 3D Display Pixel Density
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Solution Overview
Problem
Conventional 3D display systems require a large number of expensive spatial light modulators (SLMs) to achieve high pixel density and refresh rates for dynamic 3D light field displays, and they often need high intensity light sources, which increase physical size, power requirements, and cooling needs.
Innovation Solution
The method employs a single spatial light modulator in a multiplexed fashion with an array of spatially-separated light sources, where each light source is alternately activated to direct light to the SLM, creating multiple hogels through time sequencing and optical multiplexing, reducing the number of SLMs and eliminating the need for high intensity light sources within the same housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large number of spatial light modulators are used to achieve high pixel density and refresh rates, then the quality of dynamic 3D light field displays is improved, but the cost and device complexity increase significantly
Solution Approach 1:
The patent segments the SLM device into multiple independently controllable zones or regions. Each zone can be controlled separately to display different portions of the light field, enabling high pixel density through temporal multiplexing of these segmented regions rather than requiring multiple physical SLM devices.
Solution Approach 2:
The patent employs periodic switching between different zones of the SLM to create the illusion of simultaneous high-resolution display across multiple regions. By rapidly alternating between zones in a periodic manner, the system achieves high pixel density and refresh rates using a single SLM device.
2Illumination intensity
If high intensity light sources are used within the same housing, then illumination for the SLMs is improved, but the physical size, power requirements, and cooling needs increase
Solution Approach 1:
The patent merges multiple light source functions into a single integrated light source located outside the main housing. This single light source provides illumination for all SLM zones through optical coupling, eliminating the need for multiple high-intensity light sources within the housing and thereby reducing physical size, power consumption, and cooling requirements.
Solution Approach 2:
The patent introduces an intermediary optical coupling mechanism (such as fiber optics or waveguides) that efficiently transmits light from the external light source to the SLM zones. This intermediary system enables high illumination intensity at the SLM while keeping the light source physically separate, thus avoiding the drawbacks of housing multiple high-intensity sources.
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 approach dynamically creates a large number of pixels for high-quality 3D displays with reduced SLMs, lowers costs, and allows efficient sharing of light sources among multiple systems, while minimizing space and power requirements.
Implementation Method 1
Some reflective SLMs use liquid crystal on silicon (LCoS) display elements to modulate an incoming light beam through selective reflection of rays of light
Implementation Method 2
A commonly used modulation mechanisms is the electro-optical spatial light modulator containing liquid crystals as the modulation material. The optical properties of the liquid crystals are modified by an electric field
Implementation Method 3
Next, a mirror reset pulse is applied, which causes each micromirror to be electrostatically deflected about a hinge to either a +12° state or a −12° state, depending upon whether the underlying memory cell is a '1' or a '0'
Implementation Method 4
A lens focuses light from the selected light source element onto the SLM
Data Source
AI summary
In described examples, a method of creating multiple light images uses spatially-separated light sources, arranged in an array, operated in multiplexed fashion, for driving a spatial light modulator. Each of the light sources is time-sequenced to direct light at the spatial light modulator during a time interval. The spatial light modulator is synchronized with the light sources and controlled to produce a desired image during each time interval. The resulting images are received by an optical lens system to provide light images along an image plane. Alternately, the optical lens system focuses the modulated light images on a hogel plane to produce a light field. The pixel count of the spatial light modulator is effectively multiplied by the number of light sources.