Aspheric Lens Optical Package with Reflective Layer for Crosstalk Reduction
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Solution Overview
Problem
Existing optical sensor packages face challenges with wide angular field of view requirements and significant optical signal attenuation, as well as issues with blocking crosstalk, especially infrared light, due to the use of small diffuser apertures and inadequate light blocking in mold compounds.
Innovation Solution
The optical package incorporates an aspheric lens with a reflective layer and a filler material, where the reflective layer is applied to the lateral surface of the aspheric lens to control light entry and reduce crosstalk, and the filler material is used to encapsulate the lens, providing robust light blocking and improved handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a small diffuser aperture is placed near the outer surface with a large air gap to reduce incident angle range, then the angular field of view requirement is met, but optical signal is significantly attenuated (10× to 20×)
Solution Approach 1:
The patent employs an aspheric lens with a curved surface profile instead of a flat diffuser aperture. The aspheric shape refracts incoming light rays to redirect them onto the sensor surface, effectively gathering light from a wider angular field of view while maintaining proper incidence angles on the sensor. This curved optical element replaces the complex aperture-air gap structure and eliminates the associated 10× to 20× signal attenuation.
2Object-affected harmful factors
If the thickness of mold compound is increased to block infrared light crosstalk, then crosstalk blocking is improved, but package size increases
Solution Approach 1:
The patent changes the optical parameters of the mold compound by incorporating infrared-absorbing pigments or additives. This modification enables the mold compound to absorb and block infrared light crosstalk at much smaller thicknesses compared to conventional mold compounds. The parameter change in material composition allows effective crosstalk blocking without increasing package thickness.
3Object-affected harmful factors
If a reflective layer is applied to the lateral surface of the aspheric lens, then stray light and crosstalk are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies a reflective layer with specific optical properties (high reflectivity in visible range, infrared absorption) to the lateral surface of the aspheric lens. This reflective coating redirects stray light away from the sensor and blocks infrared crosstalk. The manufacturing complexity is managed by integrating this coating step into the existing lens fabrication process, making it a standard part of production rather than an additional complex operation.
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 configuration enhances optical sensitivity, reduces crosstalk, and offers improved light gathering efficiency while maintaining a compact package size, with the reflective layer and filler material effectively managing stray light and NIR light blocking.
Implementation Method 1
Light incident from small angles of incidence is refracted by the lens material. However, light incident from larger angles of incidence can also reach the optoelectronic component.
Implementation Method 2
The reflective material of the reflective layer shields the aspheric lens from light impinging on the lateral surface of the lens.
Implementation Method 3
The optoelectronic component is arranged for detecting electromagnetic radiation in the specified wavelength range.
Data Source
AI summary
An optical package is proposed comprising a carrier, an optoelectronic component, an aspheric lens, and a reflective layer. The carrier comprises electrical interconnections and the optoelectric component is arranged for emitting and/or detecting electromagnetic radiation in a specified wavelength range. Furthermore, the optoelectric component is mounted on the carrier or integrated into the carrier and electrically connected to the electric interconnections. The aspheric lens has an upper surface, a lateral surface, and a bottom surface and the bottom surface is arranged on or near the optoelectric component. The aspheric lens comprises a material which is at least transparent in the specified wavelength range. The reflective layer comprises a reflective material, wherein the reflective layer at least partly covers the lateral surface of the aspheric lens, and wherein the reflective material is at least partly reflective in the specified wavelength range.