Liquid Crystal Lens Stack for Thin VR Display Optics
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Solution Overview
Problem
There is a demand for thinner and lighter head-mounted displays used for virtual reality applications, which require improved optical components to enhance image quality and reduce bulkiness.
Innovation Solution
A lens portion comprising stacked lens elements with fixed alignment directions of liquid crystal molecules, each converting circularly polarized light of specific wavelengths into opposite polarized light, and phase conversion elements to optimize light convergence and divergence, integrated with a display device featuring retardation films and selective reflection portions to manage polarized light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional lens structures are used in head-mounted displays, then image quality can be maintained, but the device becomes thicker and heavier
Solution Approach 1:
The lens is divided into multiple lens elements (first lens element, second lens element, third lens element) with different optical functions. Each element handles specific wavelength ranges or polarization states, allowing the system to achieve superior optical performance with thinner individual components compared to a single thick lens.
Solution Approach 2:
The patent uses liquid crystal materials with specific optical properties (birefringence, polarization conversion) to create lens elements that are both thin and optically effective. The combination of liquid crystal layers with different alignment directions creates composite optical structures that maintain image quality while reducing thickness.
2Reliability
If the number of lens elements is increased to improve image quality, then optical performance enhances, but device complexity and thickness increase
Solution Approach 1:
Each lens element is designed to perform multiple functions: the first lens element converts circularly polarized light to linearly polarized light, the second lens element converges light, and the third lens element further refines the optical path. This multi-functionality within each element reduces the need for additional separate components.
Solution Approach 2:
The patent addresses chromatic aberration by designing lens elements with different dispersion characteristics for different wavelength ranges. The second lens element specifically targets blue light convergence while the third lens element handles other wavelengths, creating a dimension of wavelength-specific optimization that improves image quality without adding excessive complexity.
3Length of moving object
If lens elements are made thinner to reduce device thickness, then compactness improves, but optical performance and image quality deteriorate
Solution Approach 1:
Each lens element is optimized for specific local optical requirements: the first lens element focuses on polarization conversion, the second on blue light convergence, and the third on overall focal refinement. This localized optimization allows thin elements to achieve their specific functions effectively without compromising overall image quality.
Solution Approach 2:
The patent changes optical parameters such as refractive index, birefringence, and alignment directions to enhance the optical effectiveness of thin lens elements. By adjusting these parameters, each thin element contributes maximally to the overall optical performance, maintaining image quality despite reduced thickness.
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 solution achieves compactness and enhanced image quality by efficiently managing light polarization and convergence, allowing for high-definition virtual reality experiences.
Implementation Method 1
each of the first lens element and the second lens element includes a liquid crystal layer cured in a state in which alignment directions of a plurality of liquid crystal molecules are fixed
Implementation Method 2
a lens portion comprising: a first lens element having a lens action of converging while converting first circularly polarized light of a first wavelength into second circularly polarized light of a reverse direction
Implementation Method 3
phase conversion elements to optimize light convergence and divergence
Data Source
AI summary
According to one embodiment, a lens portion includes a first lens element converging while converting first circularly polarized light into second circularly polarized light and a second lens element converging while converting the second circularly polarized light into the first circularly polarized light. Each of the first lens element and the second lens element includes first liquid crystal molecules, and the alignment direction of the first liquid crystal molecules of the first lens element is line symmetry with the alignment direction of the first liquid crystal molecules of the second lens element.