Four-Lens Optical System for Compact Waveguide Displays
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Solution Overview
Problem
Conventional optical lenses used in waveguide display devices face challenges in achieving high resolution, reducing overall volume, and minimizing thermal drift while maintaining good optical performance.
Innovation Solution
The optical lens design consists of four lenses with specific refracting powers and materials, including a glass lens, which reduces the overall optomechanical volume and enhances thermal stability, allowing for high-resolution imaging with minimal thermal drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the number of lenses is reduced from five to four, then the overall volume of the imaging module is reduced, but the optical performance may deteriorate
Solution Approach 1:
The optical lens is segmented into four distinct lens elements (first lens L1, second lens L2, third lens L3, and fourth lens L4) with specific refracting powers arranged in sequence. This segmentation allows each lens to contribute differently to the overall optical function, achieving high-resolution imaging with reduced thermal drift while maintaining a compact structure with only four elements instead of five or more.
2Stability of the object's composition
If glass material is used for the first or third lens, then thermal stability is improved, but the manufacturing complexity increases
Solution Approach 1:
Glass material is selectively applied to specific lens elements (first lens L1 or third lens L3) rather than uniformly to all lenses. This local quality approach provides thermal stability where most needed in the optical path while keeping other lenses made from materials easier to manufacture, thus balancing thermal performance with manufacturing feasibility.
3Volume of stationary object
If a small 0.13-inch imaging element is used, then the optomechanical volume is reduced, but the resolution requirement becomes more challenging to achieve
Solution Approach 1:
The optical system employs a composite arrangement of four lens elements with different refracting powers (positive, negative, positive, and positive respectively) and different materials (including glass and non-glass materials). This composite structure enables the compact 0.13-inch imaging module to achieve high spatial resolution of 125 lp/mm by optimizing the combined optical effects of all lens elements.
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 design achieves a spatial resolution of 125 lp/mm and reduces the overall volume of the imaging module by minimizing the number of lenses from five to four, while maintaining good optical performance and low thermal drift.
Implementation Method 1
The optical lens sequentially includes a first lens, a second lens, a third lens, and a fourth lens with refracting power along an optical axis from a light incidence side to a light exit side
Data Source
AI summary
An optical lens adapted to receive an image beam from an imaging element is provided. The optical lens sequentially includes a first lens, a second lens, a third lens, and a fourth lens with refracting power along an optical axis from a light incidence side to a light exit side, and the first lens to the fourth lens each include a light incidence surface facing the light incidence side and a light exit surface facing the light exit side. The first lens has positive refracting power. The second lens has negative refracting power. The third lens has positive refracting power. The first lens or the third lens is made of glass. The optical lens receives the image beam from the light incidence side. The image beam forms a stop on the light exit side, and the image beam forms the minimum beam cross-section at a location of the stop.