Aspherical Lens Projection System for Compact Vehicle Headlamps
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Solution Overview
Problem
Conventional projection systems used in vehicles, such as headlamps, incorporate multiple spherical glass lenses, leading to larger system sizes and higher costs due to the complexity and number of lenses required.
Innovation Solution
The proposed projection system utilizes a configuration of three aspherical lenses, sequentially arranged, which reduces the number of lenses needed while maintaining or improving image quality. This configuration includes a first lens with positive optical power, a second lens with negative optical power, and a third lens with positive optical power, optimized to achieve specific parameters such as field-of-view angle, chief ray angle, and throw ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple spherical glass lenses are used in the projection system, then the image quality can be maintained, but the system size and cost increase
Solution Approach 1:
The patent changes the fundamental parameter of lens geometry from spherical to aspherical surfaces. This parameter change allows a single lens to achieve optical performance that previously required multiple spherical lenses, thereby reducing the total number of lenses while maintaining or improving image quality. The aspherical surfaces enable better control of light rays, reducing aberrations and improving focus.
Solution Approach 2:
The patent employs composite optical designs where aspherical lenses combine different optical powers (positive and negative) in a single integrated optical path. This composite approach within each lens element allows the system to achieve the optical correction that previously required separate spherical lenses, reducing overall system complexity.
2Reliability
If multiple spherical glass lenses are used in the projection system, then the optical performance can be achieved, but the system size increases
Solution Approach 1:
By changing from spherical to aspherical lens parameters, the optical path is optimized to achieve the required performance in a more compact configuration. The aspherical surfaces provide better light control, allowing for shorter optical paths while maintaining image quality, thus reducing the overall system length.
Solution Approach 2:
The patent explicitly uses aspherical (non-spherical) lens surfaces instead of traditional spherical surfaces. This curvature modification enables more efficient light focusing and aberration correction, allowing the optical system to be more compact while achieving superior or equal optical performance compared to multiple spherical lenses.
3Ease of manufacture
If conventional spherical lenses are used, then the design is simpler to manufacture, but the number of lenses and system complexity increase
Solution Approach 1:
While aspherical lenses are more complex to manufacture individually, the patent reduces the total number of lenses required. This trade-off results in fewer manufacturing steps overall, as producing three aspherical lenses requires less total manufacturing effort than producing multiple spherical lenses with additional alignment and assembly requirements.
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 use of aspherical lenses in the projection system results in a more compact design, improved image quality with high resolution and relative illumination, and reduced aberrations, thus addressing the size and cost issues of conventional systems while enhancing performance.
Implementation Method 1
The projection system includes a first lens 10, a second lens 30, and a third lens 50, which are sequentially disposed from a projection surface P toward an image source surface Q
Data Source
AI summary
A projection system includes a first lens, a second lens, and a third lens arranged in sequence from a projection surface to an image source surface. The projection system satisfies expressions below:10°<DFOV<14°;CRA<0.52°;4.2<TR<5.9;0.29<f1/f23<0.75;0.67<f3/f12<1.73;12<OTL/IH<15;and 1.1<CT3/ET3<1.3.Wherein: DFOV is a maximal field-of-view angle of the projection system; CRA is a chief ray angle; TR is a throw ratio; f1 is a focal length of the first lens; f23 is a combined focal length of the second lens and the third lens; f3 is a focal length of the third lens; f12 is a combined focal length of the second lens and the first lens; OTL is an optical total length; IH is a maximum image height on the image source surface; CT3 is a center thickness of the third lens; ET3 is an edge thickness of the third lens. An illumination device is further disclosed.