Optical Module Liquid Crystal Lens Thickness Reduction
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Solution Overview
Problem
Conventional pancake lens blocks used in near-eye display devices are too thick and expensive, making them unsuitable for mass production and user comfort.
Innovation Solution
The optical module includes a quarter wave plate, polarization converters, a lens assembly with a liquid crystal lens, and a polarization reflection film, arranged in a sequence that modulates the polarization state and focus of the image light, while reducing the number of optical surfaces and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional pancake lens with multiple optical surfaces is used, then the optical functionality is achieved, but the thickness and cost increase significantly
Solution Approach 1:
The patent combines multiple optical surfaces into a single integrated lens structure. Instead of stacking separate optical components with multiple air-glass interfaces, the invention integrates the optical functions into one monolithic lens that achieves the same beam shaping and focusing capabilities with fewer interfaces, thereby reducing overall thickness and manufacturing complexity
Solution Approach 2:
The single lens structure performs multiple optical functions simultaneously - beam expansion, focusing, and wavefront shaping - that would traditionally require separate optical elements. This multi-functional design eliminates the need for multiple specialized components, reducing both the number of optical surfaces and the overall device thickness
2Device complexity
If a conventional pancake lens with multiple optical surfaces is used, then the optical functionality is achieved, but the manufacturing cost increases
Solution Approach 1:
By merging multiple optical surfaces into a single lens component, the patent reduces the number of separate parts that need to be manufactured, aligned, and assembled. This integration simplifies the manufacturing process, reduces material waste, and lowers overall production costs while maintaining optical performance
Solution Approach 2:
The patent segments the optical functions within a single monolithic structure, allowing for more efficient manufacturing compared to assembling multiple separate components. The single-lens approach enables streamlined production processes and reduces the complexity of precision alignment required in multi-component systems
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 enhances the field of view, reduces the volume of the head-mounted display, and improves image display quality by folding the optical path and minimizing optical surfaces.
Implementation Method 1
a lens assembly with a liquid crystal lens
Implementation Method 2
modulates the polarization state and focus of the image light
Implementation Method 3
a quarter wave plate, polarization converters
Implementation Method 4
a polarization reflection film, arranged in a sequence that modulates the polarization state
Data Source
AI summary
An optical module includes a quarter wave plate, a first polarization converter, a second polarization, a lens assembly and a polarization reflection film. The quarter wave plate converts a polarization state of image light received. The first polarization converter and the second polarization converter receive the image light from the quarter-wave plate and focus the image light to a target position. The lens assembly includes a liquid crystal lens with a flat surface and a curved surface. The curved surface protrudes towards the quarter wave plate to make the liquid crystal lens to deflect the image light. The polarization reflection film receives the image light from the second polarization converter. The polarization reflection film is configured to transmit the image light having a target polarization state. The image light from the polarization reflection film converges at the target position to display an image.