Holographic Display Using Electrowetting Prisms for Wide Viewing Angles
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Solution Overview
Problem
Holographic image display devices face limitations in viewing angle due to the large pixel pitch of spatial light modulators, resulting in a narrow viewing angle and reduced resolution compared to analog holography systems.
Innovation Solution
The use of electrowetting prisms to adjust the optical path of light, in conjunction with a spatial light modulator, increases the viewing angle by refracting and diffracting light in multiple directions, enhancing the display's resolution and viewing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a spatial light modulator with large pixel pitch is used, then the device complexity is reduced and ease of manufacture is improved, but the viewing angle becomes narrow and resolution decreases
Solution Approach 1:
The patent divides the optical path adjustment function into multiple electrowetting prisms arranged in an array, with each prism controlling a specific angular direction. This segmentation allows the system to achieve wide viewing angles and high resolution through coordinated operation of multiple smaller units, rather than requiring a single large-pitch SLM element
Solution Approach 2:
The electrowetting prisms serve as intermediary optical elements between the light source and the SLM. These prisms refract light at different angles before it reaches the SLM, effectively compensating for the large pixel pitch limitation and enabling precise angular control without requiring smaller pitch SLM elements
2Device complexity
If a spatial light modulator with large pixel pitch is used, then device complexity is reduced, but the viewing angle becomes narrow
Solution Approach 1:
The electrowetting prisms utilize dynamically controllable refractive indices through applied voltages, allowing real-time adjustment of light refraction angles. This dynamic control enables the system to adapt to different viewing angles and directions without changing the physical structure of the SLM, thereby achieving wide viewing angles with a relatively simple device configuration
Solution Approach 2:
The patent changes the refractive index parameter of the electrowetting prism materials through applied electrical voltages. By controlling the degree of refraction through parameter adjustment rather than structural modification, the system achieves wide viewing angles while maintaining low device complexity
3Manufacturing precision
If analog holography with optical recording material is used, then resolution is improved, but cost and size increase
Solution Approach 1:
The patent uses a digital SLM to generate and modulate holographic interference patterns, creating a digital copy of the holographic information rather than requiring physical optical recording materials. This approach maintains high resolution through precise digital control while significantly reducing the size and complexity of the overall system
Solution Approach 2:
The invention replaces the mechanical and chemical processes of analog optical recording with an electrically controlled digital modulation system. The SLM uses electrical signals to control light phase and amplitude, substituting complex mechanical recording mechanisms with simpler electronic control while achieving comparable or superior resolution
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 configuration significantly increases the horizontal and vertical viewing angles, allowing for a clearer and more expansive holographic image display, reducing the distance between the device and the image, and enabling its use in mobile devices.
Implementation Method 1
each of the plurality of electrowetting prisms includes electrodes and an interface-determining material. The interface-determining material of each of the plurality of electrowetting prisms includes a first interface surface, and a shape of the first interface surface varies according to voltages applied to the electrodes
Implementation Method 2
the light emitted from the backlight is refracted at the first interface surface of the interface-determining material of each of the plurality of electrowetting prisms. The angle in which the light is refracted at the first interface surface of the interface-determining material of each of the plurality of electrowetting prisms is based on a shape of the corresponding first interface surface
Implementation Method 3
A digital holographic image display device uses a spatial light modulator (SLM) instead of the optical recording material. The SLM may generate an interference pattern in real time depending on an input signal. Light transmitted through the SLM reconstructs a holographic image that corresponds to the interference pattern
Data Source
AI summary
A holographic image display device includes a backlight for emitting light. An optical path adjuster includes a plurality of electrowetting prisms. Each of the plurality of electrowetting prisms is configured to adjust an optical path of the light. A spatial light modulator includes a plurality of pixels. Each of the plurality of pixels is configured to modulate an amplitude or a phase of the light.