Aspherical Projection Lens Design for Compact High-Resolution Imaging
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Solution Overview
Problem
Traditional projection apparatuses face challenges in achieving a large projection view angle with small size and light weight due to the need for numerous spherical lenses to correct aberration and image blur, resulting in a heavy and bulky device.
Innovation Solution
A projection apparatus utilizing a projection lens with a combination of at least three aspherical lenses, where the effective focal length is between 5 mm and 8 mm, and the sum of the effective focal length and number of lenses is between 14 and 17, reducing the overall number of lenses to 6 to 12, thereby minimizing weight and size while maintaining a large projection view angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spherical lenses are used to correct aberration and image blur, then image quality is improved, but the number of lenses increases rapidly, resulting in increased device size and weight
Solution Approach 1:
The patent changes the fundamental parameter of lens surface geometry from spherical to aspherical. This parameter change allows a single aspherical lens to correct multiple types of aberrations (spherical aberration, coma, astigmatism) that would otherwise require multiple spherical lenses, thereby reducing the total lens count and device weight while maintaining image quality
Solution Approach 2:
The patent employs composite optical design by combining aspherical lenses with specific refractive indices and dispersion characteristics. The projection lens system uses lenses with different material properties (refractive indices ranging from 1.48 to 1.80) to achieve aberration correction with fewer elements, reducing overall device weight
2Length of stationary object
If the focal length is reduced to achieve compact size, then device size is minimized, but the number of lenses must increase to maintain image quality, counteracting the size reduction benefit
Solution Approach 1:
The patent applies aspherical surface parameters to lenses with short focal lengths (5mm-8mm), enabling these compact lenses to correct aberrations effectively. The aspherical coefficients (A4, A6, A8, A10) are specifically optimized for short-focal-length projection, allowing reduced device size without compromising image quality or requiring increased lens count
Solution Approach 2:
Each aspherical lens in the projection system performs multiple functions simultaneously: focusing light, correcting spherical aberration, correcting coma, and correcting astigmatism. This multi-functionality allows the projection lens to achieve high image quality with only 6-12 lenses, maintaining compact size while avoiding increased complexity
3Weight of stationary object
If aspherical lenses are used instead of spherical lenses, then the number of lenses is reduced and device weight is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent provides specific aspherical coefficient ranges (A4: -0.0005 to -0.0001, A6: -0.00005 to -0.00001, A8: -0.00001 to -0.000001, A10: -0.000001 to -0.0000001) that balance manufacturing feasibility with optical performance. These controlled parameter specifications enable precision manufacturing while achieving the desired weight reduction through aspherical lens design
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 effectively reduces the number of lenses, resulting in a lighter and more compact projection apparatus with a short focal length and large projection view angle, addressing the issue of weight and size while maintaining image quality.
Implementation Method 1
The projection lens includes a plurality of lenses. The lenses have an optic axis, and the light passes through the lenses and is projected on the projection screen
Data Source
AI summary
The present invention provides a projection apparatus including an image generation device and a projection lens. The projection lens is disposed between a light valve of the image generation device and a projection screen, and the projection lens includes a plurality of lenses. The lenses include a first lens, a second lens and a third lens, and the first lens, the second lens and the third lens are aspherical lenses. An effective focal length of the projection lens is between 5 mm and 8 mm, and a sum of the effective focal length of the projection lens and a number of the lenses is between 14 and 17.