Five-Lens Optical System for Compact Head-Mounted Displays
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Solution Overview
Problem
Existing waveguide displays face challenges in achieving a compact, lightweight, high-resolution optical lens with a large viewing angle due to the size and weight constraints of conventional optical lens designs.
Innovation Solution
The optical lens is designed with a sequential arrangement of five lenses (first, second, third, fourth, and fifth lenses) from the light exit side to the light incident side, including a stop at the light exit side to minimize the light beam cross-sectional area, which allows for a shorter length, reduced weight, and increased resolution, while maintaining a larger viewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional optical lens designs are used, then the lens can achieve basic imaging function, but the size and weight become too large for compact head-mounted displays
Solution Approach 1:
The optical lens is divided into five separate lens elements (first lens L1, second lens L2, third lens L3, fourth lens L4, and fifth lens L5) with different refractive powers arranged in sequence. Each lens element contributes to the overall imaging function while allowing for compact individual dimensions, thereby achieving a smaller total volume while maintaining imaging performance through the combined optical power of all elements.
2Length of moving object
If the optical lens length is reduced for compactness, then the device becomes more portable, but the resolution and viewing angle may deteriorate
Solution Approach 1:
Each lens element is designed with specific local optical properties: the first lens L1 has positive refractive power for initial convergence, the second lens L2 has negative refractive power for divergence control, the third lens L3 has positive refractive power for intermediate focusing, the fourth lens L4 has negative refractive power for aberration correction, and the fifth lens L5 has positive refractive power for final image formation. This localized optimization of optical properties in each element enables high resolution and large viewing angle within a shortened overall length.
3Measurement precision
If more lens elements are added to improve resolution, then the imaging quality increases, but the device complexity and weight increase
Solution Approach 1:
The five lens elements are merged into a single integrated optical lens assembly that functions as one unified imaging system. The stop is strategically positioned between the second lens L2 and third lens L3 to control the light beam cross-sectional area at the optimal location. This merging approach achieves high resolution through the combined optical power of all elements while managing complexity through a cohesive design where each element serves a specific function in the overall imaging chain.
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 design results in a smaller, lighter, and more efficient optical lens that provides a higher resolution and larger viewing angle, optimizing the display's volume and imaging performance.
Implementation Method 1
an image light beam provided by a panel passes through an optical lens and enters a waveguide
Implementation Method 2
A virtual image corresponding to the image generated by an image source (the panel) may be formed at a distance by using the optical lens
Data Source
AI summary
An optical lens and a head-mounted display device including the optical lens are provided. The optical lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from a light exit side to a light incident side. An image generator is disposed at the light incident side. The optical lens is configured to receive an image light beam provided by the image generator. A stop is formed at the light exit side of the image light beam. At the stop, the image light beam has a minimum light beam cross-sectional area. The technical solution of the invention may be used to shorten an overall length of the optical lens, so as to reduce an appearance volume of the display.