Tunable Liquid Crystal Grating for Holographic 3D Display
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Solution Overview
Problem
Current holographic true 3D display technologies face limitations in achieving large viewing angles and sizes due to the constraints of spatial light modulators, resulting in a restricted and small viewing experience for users.
Innovation Solution
A tunable liquid crystal grating-based holographic display system that uses a laser, spatial light modulator, and tunable liquid crystal grating to generate a secondary diffraction effect, expanding the viewing angle and size by controlling the voltage applied to the liquid crystal grating, allowing for seamless splicing of sub-holograms to enhance the display's dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If multiple spatial light modulators are spliced together to expand viewing angle, then viewing angle increases, but system complexity and cost increase
Solution Approach 1:
A tunable liquid crystal grating is introduced as an intermediary component between the spatial light modulator and the observation space. This grating performs the function of expanding the viewing angle through diffraction, replacing the need for multiple spliced spatial light modulators. The grating acts as a mediator that transforms the light field to achieve wide-angle viewing without increasing system complexity
Solution Approach 2:
The patent replaces the mechanical splicing of multiple spatial light modulators with an optical field manipulation approach using a liquid crystal grating. Instead of physically assembling multiple devices, the system uses voltage-controlled diffraction to achieve the same effect of expanding viewing angle, thereby eliminating mechanical complexity
2Stress or pressure
If multiple spatial light modulators are used to increase viewing angle, then viewing angle expands, but manufacturing cost increases
Solution Approach 1:
The tunable liquid crystal grating serves as a cost-effective intermediary that achieves viewing angle expansion through optical diffraction rather than requiring expensive multiple spatial light modulators. This single grating component replaces the need for multiple expensive devices, significantly reducing manufacturing cost while maintaining the viewing angle expansion function
Solution Approach 2:
The patent utilizes voltage-controlled parameter changes in the liquid crystal grating to dynamically adjust diffraction characteristics. By changing the voltage applied to the grating, the system can control the diffraction angle and order, providing viewing angle expansion without the need for multiple fixed devices, thereby reducing manufacturing cost
3Device complexity
If conventional spatial light modulator is used, then system is simple, but reconstructed image size is small
Solution Approach 1:
The patent introduces a new dimension of diffraction order control by placing the tunable liquid crystal grating in the optical path. This adds a diffraction dimension to the existing holographic reconstruction, enabling the system to generate multiple diffraction orders that correspond to multiple virtual images. This dimensional expansion allows large-size reconstruction without complicating the base system structure
Solution Approach 2:
The system employs dynamic control of the liquid crystal grating through voltage adjustment to change diffraction characteristics in real-time. This dynamic capability allows the system to switch between different diffraction orders and angles, enabling flexible control of reconstructed image size while maintaining system simplicity through a single controllable component
4Stress or pressure
If convex parabolic mirror method is used to enlarge horizontal viewing angle, then viewing angle increases, but reconstructed image size becomes very small
Solution Approach 1:
The tunable liquid crystal grating acts as an intermediary that simultaneously controls both diffraction angle and image size through voltage adjustment. Unlike the convex parabolic mirror that only affects angle, the grating can independently control the diffraction order and spatial distribution, enabling both wide viewing angle and large image size to be achieved together without the trade-off present in mirror-based methods
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
The system achieves a significant increase in viewing angle and size of the holographic 3D display, with the viewing angle expanded to approximately 35° and the display size enlarged by 3.7 times the original, providing a more immersive and larger 3D experience without altering the reconstruction distance or viewing angle.
Implementation Method 1
a laser, a filter and the beam expander are used for generating collimated incident light
Implementation Method 2
the input light is modulated by a spatial light modulator to recreate a 3D scene
Implementation Method 3
the tunable liquid crystal grating is driven by voltage, wherein the voltage is applied to control a diffraction image to generate a secondary diffraction so as to enlarge the viewing angle and size
Implementation Method 4
Tunable liquid crystal grating-based holographic true 3D display system
Data Source
AI summary
A tunable-liquid-crystal-grating-based holographic true 3D display system comprises a laser, a filter, a beam expander, a semi-transparent semi-reflective mirror, a spatial light modulator, a lens I, a diaphragm, a tunable liquid crystal grating, a polaroid, a signal controller, a lens II and a receiving screen. The laser, the filter and the beam expander are used for generating collimated incident light. The spatial light modulator is loaded with a hologram of a 3D object. The diaphragm is positioned behind the lens I for eliminating a high-order diffracted light in the holographic true 3D display. The tunable liquid crystal grating is located on the back focal plane of the lens I and on the front focal plane of the lens II, and the signal controller is used for synchronously controlling the voltage of the tunable liquid crystal grating and the generation and loading of the hologram.