MEMS Spatial Light Modulator for Dynamic Hologram Display
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for displaying computer-generated holograms are limited by the need for high-resolution optical microphotography systems, which restrict the display to static holograms and are costly, especially when using liquid crystal spatial light modulators, making it difficult to fabricate large area dynamic holograms.
Innovation Solution
A spatial light modulator comprising MEMS units arranged in an array, with each unit having a signal processing device and a driving device to move a light shielding portion based on Lohmann encoding, enabling fast and dynamic display of computer-generated holograms over a large area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If liquid crystal spatial light modulator is used to display computer generated hologram, then dynamic hologram can be displayed, but fabrication cost is high and large area fabrication is difficult
Solution Approach 1:
The spatial light modulator is divided into multiple independent MEMS units arranged in an array, where each unit can be independently controlled to display a portion of the hologram. This segmentation enables parallel processing and simplifies fabrication, as each MEMS unit can be manufactured separately and then assembled into a larger array, making large area fabrication feasible and cost-effective.
Solution Approach 2:
The patent replaces the liquid crystal material-based spatial light modulator with a mechanical MEMS-based system. Instead of using liquid crystal molecules that require complex electrical addressing and have slow response times, the invention uses micro-electro-mechanical structures with movable light shielding portions that can be rapidly positioned to modulate light, achieving fast dynamic hologram display with simpler fabrication.
2Manufacturing precision
If high resolution optical microphotography system is used, then static hologram can be displayed with high precision, but the system is costly and cannot display dynamic holograms
Solution Approach 1:
The patent introduces dynamic control capability by enabling each MEMS unit to independently move its light shielding portion in real-time. This dynamic adjustment allows the system to display changing holographic patterns without requiring complex optical reconfiguration, achieving both high resolution and dynamic performance with a relatively simple optical system.
Solution Approach 2:
The invention changes the control parameter from static optical properties (as in conventional microphotography systems) to dynamic mechanical position of light shielding portions. By controlling the position of opaque elements within each MEMS unit, the system achieves high-resolution hologram display through spatial modulation, eliminating the need for expensive high-resolution optical microphotography equipment.
3Productivity
If computer generated hologram is displayed on computer screen or printed on film, then hologram can be generated, but it requires microfilming process and can only display static hologram
Solution Approach 1:
The MEMS-based spatial light modulator is a self-contained device that directly generates and displays holographic patterns without requiring external microfilming processes. The movable light shielding portions within each MEMS unit actively modulate incident light to create the hologram, enabling the system to produce dynamic holograms in real-time without time-consuming photographic processing steps.
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 the display of dynamic computer-generated holograms over a large area with fast response times, overcoming the limitations of conventional methods by using MEMS units for efficient and cost-effective large area hologram display.
Implementation Method 1
Each of the sensing devices is configured for receiving position information which is obtained through Lohmann encoding a pixel corresponding to an MEMS unit comprising the sensing device by a computer
Implementation Method 2
Conventional optical holography records information of phase and amplitude of object light wave on some kind of media in the form of interference fringes through introducing reference light wave that is coherent with the object light wave to interfere the object light wave according to the principle of optical interference
Implementation Method 3
reconstruct the original object light wave to form a 3D image of the original object according to the principle of light diffraction
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A spatial light modulator and a method for displaying a computer generated hologram using the spatial light modulator and configured for displaying a dynamic computer generated hologram in a large area are disclosed. The spatial light modulator includes a plurality of MEMS units (20) arranged in an array, each of the MEMS units (20) corresponds to a pixel of a computer generated hologram and includes a sensing device (201), a light shielding portion (202) and a driving device (203). The sensing device (201) is configured for receiving position information that is obtained through Roman encoding a pixel corresponding to an MEMS unit including the sensing device (201) by a computer, the position information is position information of the light shielding portion (202) when a present frame is displayed, and the position information is transmitted to the driving device (203) by the sensing device (201). The driving device (203) is configured for controlling the light shielding portion (202) to move to a position corresponding to the position information of the light shielding portion (202) when the present frame is displayed in response to the received position information of the light shielding portion (202) when the present frame is displayed.