AR Optical Imaging Module Lens Focal Power Optimization
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Solution Overview
Problem
Current AR devices are heavy, which negatively impacts user experience due to their weight, and there is a need for an optical imaging module that balances optical performance and weight to enhance comfort in wear.
Innovation Solution
An optical imaging module comprising a lens assembly with a specific distribution of focal powers among its lenses and a light source, where the distance between the light source and stop is optimized relative to the maximum lens diameter, reducing the overall weight and improving optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a traditional optical imaging module is used in AR devices, then optical performance can be achieved, but the device weight increases
Solution Approach 1:
The patent applies parameter changes by optimizing the focal length parameters of individual lenses (f1, f2, f3, f4) and their ratios to achieve a balanced optical system. By carefully selecting and adjusting these parameters, the system achieves good optical performance while using fewer lenses, thereby reducing the overall weight of the AR device.
Solution Approach 2:
The optical system is segmented into multiple lenses with specific focal power distributions. The first lens has positive focal power, the second lens has negative focal power, the third lens has positive focal power, and the fourth lens has negative focal power. This segmentation allows each lens to perform specific optical functions, achieving good overall optical performance while using a controlled number of components to minimize weight.
2Measurement precision
If more lenses are added to improve optical performance, then image clarity improves, but device weight increases
Solution Approach 1:
The patent optimizes the focal length parameters of each lens and their ratios to achieve good optical performance with a controlled number of lenses. By carefully selecting parameters such as f1/f2, f3/f4, and their relationships to the stop position and lens diameters, the system achieves high image clarity without requiring excessive numbers of lenses, thus minimizing weight.
Solution Approach 2:
The patent uses composite optical design combining lenses with different focal powers (positive and negative) to achieve superior optical performance. The specific combination of first lens (positive), second lens (negative), third lens (positive), and fourth lens (negative) creates a composite optical system that delivers high image clarity while maintaining a manageable component count for weight reduction.
3Weight of moving object
If the optical imaging module size is reduced for lightweight AR device, then weight decreases, but optical efficiency may deteriorate
Solution Approach 1:
The patent optimizes critical parameters including the distance between the light source and stop (TL), the maximum lens diameter (D), and the focal length ratios (f1/f2, f3/f4) to achieve high optical efficiency within a compact form factor. By carefully controlling these parameters, the system maintains excellent optical performance while minimizing the overall size and weight of the imaging module.
Solution Approach 2:
The patent addresses the size-performance tradeoff by optimizing the spatial arrangement of optical components in multiple dimensions. The specific positioning of lenses relative to the stop and light source, along with their focal length relationships, creates an efficient three-dimensional optical architecture that achieves high optical efficiency without requiring excessive linear dimensions, thereby reducing weight.
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 results in a lightweight AR device with improved optical efficiency, ensuring better user experience by maintaining high image clarity and reducing distortion, while being suitable for various temperatures and interpupillary distances.
Implementation Method 1
The lens assembly includes a first lens, a second lens, a third lens, and a fourth lens arranged in order... the first lens has a positive focal power, the second lens has a positive focal power, the third lens has a negative focal power, and the fourth lens has a positive focal power
Data Source
AI summary
The present disclosure provides an optical imaging module, comprising: a stop, a lens assembly, and a light source; the lens assembly includes a first lens, a second lens, a third lens, and a fourth lens arranged in order, with the light source located on the object side of the fourth lens, and the stop located on the image side of the first lens; the first lens has a positive focal power, the second lens has a positive focal power, the third lens has a negative focal power, and the fourth lens has a positive focal power; and the optical imaging module satisfies the inequality: 0.5 mm<TL/D<3 mm; where TL is the distance between the light source and the stop, and D is the maximum lens diameter of the first lens, the second lens, the third lens, and the fourth lens.