Five-Lens Optical Design for Compact Head-Mounted Displays
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Solution Overview
Problem
Existing waveguide displays face challenges in achieving a balance between size, weight, viewing angle, and resolution due to the limitations of conventional optical lens designs, which often result in larger and heavier devices with restricted field angles.
Innovation Solution
The optical lens design comprises a sequence of five lenses with specific refractive powers and configurations, including biconvex and aspherical lenses, optimized to minimize length and weight while maximizing the field angle and resolution, with a stop at the light exit side to manage the image light beam effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional optical lens designs are used, then the device can achieve basic imaging function, but the device size and weight increase
Solution Approach 1:
The optical lens is divided into five separate lens elements (first lens, second lens, third lens, fourth lens, and fifth lens) with different refractive powers and configurations. This segmentation allows each lens element to be optimized for specific functions, achieving compact overall volume while maintaining superior imaging performance through coordinated operation of the individual elements.
Solution Approach 2:
Different lens elements are assigned different local optical properties: the first and fourth lenses have positive refractive power, while the second and third lenses have negative refractive power. The fifth lens also has positive refractive power. This local differentiation of optical qualities enables precise control of light propagation at different stages, achieving both compact size and high imaging quality.
2Adaptability or versatility
If conventional optical lens designs are used, then the device structure is simple, but the viewing angle and resolution are limited
Solution Approach 1:
The optical system is segmented into five distinct lens elements with alternating positive and negative refractive powers. This segmentation enables the system to handle a wider range of light angles simultaneously, expanding the viewing angle while the modular structure keeps the overall design manageable despite the increased number of elements.
Solution Approach 2:
The optical system utilizes parameter changes by varying the refractive power signs and magnitudes across the five lens elements. The first lens has positive refractive power, the second has negative refractive power, the third has negative refractive power, the fourth has positive refractive power, and the fifth has positive refractive power. This systematic parameter variation enables broader angular acceptance and higher resolution.
3Adaptability or versatility
If conventional optical lens designs are used, then the device weight is reduced, but the field angle and resolution decrease
Solution Approach 1:
The optical lens is divided into five separate lens elements (first lens, second lens, third lens, fourth lens, and fifth lens) with different refractive powers and configurations. This segmentation allows each lens element to be optimized for specific functions, achieving compact overall volume while maintaining superior imaging performance through coordinated operation of the individual elements.
Solution Approach 2:
Different lens elements are assigned different local optical properties: the first and fourth lenses have positive refractive power, while the second and third lenses have negative refractive power. The fifth lens also has positive refractive power. This local differentiation of optical qualities enables precise control of light propagation at different stages, achieving both compact size and high imaging quality.
4Length of moving object
If the optical lens length is minimized, then the device becomes more compact, but the image quality and resolution may deteriorate
Solution Approach 1:
The optical lens is divided into five separate lens elements (first lens, second lens, third lens, fourth lens, and fifth lens) with different refractive powers and configurations. This segmentation allows each lens element to be optimized for specific functions, achieving compact overall volume while maintaining superior imaging performance through coordinated operation of the individual elements.
Solution Approach 2:
The optical system utilizes parameter changes by varying the refractive power signs and magnitudes across the five lens elements. The first lens has positive refractive power, the second has negative refractive power, the third has negative refractive power, the fourth has positive refractive power, and the fifth has positive refractive power. This systematic parameter variation enables broader angular acceptance and higher resolution.
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 compact, lightweight optical lens with a larger viewing angle and higher resolution, enhancing the overall performance of waveguide displays by reducing volume and improving image projection efficiency.
Implementation Method 1
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
Implementation Method 2
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
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D
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.