Aspherical VR Optical System for Expanded Field of View
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Solution Overview
Problem
Existing VR display devices with catadioptric pancake-shaped structures suffer from low light-emitting efficiency, ghosting, and a small field of view, leading to poor visual experience.
Innovation Solution
An optical system comprising a positive focal power lens and a negative focal power lens with specific refractive indices and surface configurations, including aspherical surfaces, to refract light at large angles, reducing aberrations and increasing the field of view while maintaining a lightweight and thin design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a catadioptric pancake-shaped structure is used in VR display devices, then the device achieves a compact and thin design, but it suffers from low light-emitting efficiency, ghosting, and a small field of view
Solution Approach 1:
The patent employs aspherical surfaces on both the positive and negative focal power lenses. The positive focal power lens has an aspherical object-side surface and an aspherical image-side surface, while the negative focal power lens has an aspherical object-side surface and an aspherical image-side surface. These aspherical designs enable light rays to be refracted at large angles while reducing spherical aberrations, thereby improving light-emitting efficiency and expanding the field of view without compromising the compact pancake-shaped structure.
2Volume of moving object
If a catadioptric pancake-shaped structure is used in VR display devices, then the device achieves a compact and thin design, but it suffers from ghosting and reduced image quality
Solution Approach 1:
The patent specifies precise parameter ranges for the optical system: the positive focal power lens has a focal length of 4.0 mm to 6.0 mm and a refractive index of 1.70 to 2.00, while the negative focal power lens has a focal length of -3.0 mm to -5.0 mm and a refractive index of 1.50 to 1.70. The aspherical coefficients are also carefully controlled within specific ranges. These parameter optimizations reduce spherical aberrations and ghosting, ensuring high image quality in the compact pancake-shaped VR display device.
3Device complexity
If conventional lens designs are used in VR display devices, then the device structure is simpler, but the field of view remains small and light-emitting efficiency is low
Solution Approach 1:
The patent utilizes aspherical surfaces on all four surfaces of the lens system (object-side and image-side surfaces of both positive and negative focal power lenses). These aspherical designs enable the lenses to refract light at large angles effectively, expanding the field of view to 90 degrees or more while maintaining a compact form factor. The aspherical coefficients are optimized to balance field of view expansion with aberration control.
4Ease of manufacture
If conventional lens designs are used in VR display devices, then manufacturing is easier, but spherical aberrations and ghosting are significant
Solution Approach 1:
The patent defines specific parameter ranges for manufacturing: the positive focal power lens has a focal length of 4.0 mm to 6.0 mm and refractive index of 1.70 to 2.00, while the negative focal power lens has a focal length of -3.0 mm to -5.0 mm and refractive index of 1.50 to 1.70. The aspherical coefficients are constrained within optimized ranges that balance manufacturing feasibility with aberration correction performance. These parameter specifications enable mass production while maintaining high optical quality.
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 optical system enhances image quality by reducing spherical aberrations and ghosting, improves light-emitting efficiency, and increases the field of view to over 90 degrees, providing a more immersive experience with a compact and comfortable VR display device.
Implementation Method 1
a positive focal power lens and a negative focal power lens with specific refractive indices and surface configurations, including aspherical surfaces, to refract light at large angles
Implementation Method 2
a positive focal power lens and a negative focal power lens with specific refractive indices and surface configurations, including aspherical surfaces, to refract light at large angles
Data Source
AI summary
An optical system has an optical axis, and includes a positive focal power lens, a negative focal power lens and a display. The positive focal power lens includes a first convex surface away from the display and a second convex surface proximate to the display. The negative focal power lens includes a third convex surface away from the display and a fourth concave surface proximate to the display. For a refractive index of the positive focal power lens and a refractive index of the negative focal power lens, one is greater than another, and a greater refractive index is a first refractive index, a smaller refractive index is a second refractive index, the first refractive index is greater than 1.7, the second refractive index is greater than 1.5, and a ratio of the first refractive index to the second refractive index is less than or equal to 2.