Ambient Light Sensor Lens Diffuser Infrared Blocking
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Solution Overview
Problem
Existing light diffuser layers for ambient light sensors in electronic devices can have undesired light transmission characteristics if not properly formed, leading to measurement inaccuracies due to directional light sources.
Innovation Solution
A light diffuser system is implemented with a substrate, a lens layer formed from ultraviolet-light-curable polymer, and an optional polymer buffer layer containing light-scattering particles, which includes an infrared-light-blocking-and-visible-light-transmitting filter structure to reduce infrared light interference and enhance light diffusion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light diffuser layer with light-scattering particles is used to reduce directional light impact, then measurement accuracy is improved, but the light transmission characteristics may become undesired
Solution Approach 1:
The light diffuser is divided into multiple functional layers: a first light-scattering layer with larger particles for primary diffusion, a second light-scattering layer with smaller particles for fine-tuned diffusion, and an infrared-blocking layer. This segmentation allows each layer to contribute differently to light diffusion while maintaining desirable transmission characteristics.
Solution Approach 2:
Different regions of the light diffuser have different optical properties. The first light-scattering layer uses particles with larger average diameter for stronger scattering, while the second layer uses smaller particles for gentler scattering. The infrared-blocking layer is positioned specifically to address infrared interference without affecting visible light transmission uniformly.
2Measurement precision
If multiple layers are added to improve light diffusion and infrared blocking, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
Multiple functional layers are merged into a single integrated light diffuser component. The first light-scattering layer, second light-scattering layer, and infrared-blocking layer are combined in one structure, achieving multiple functions (visible light diffusion and infrared blocking) without requiring separate components.
Solution Approach 2:
The light diffuser structure serves multiple purposes simultaneously: it diffuses visible ambient light to reduce directional effects, blocks infrared light to prevent sensor interference, and maintains desirable light transmission characteristics. This multi-functionality reduces the need for separate components.
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 measurement errors by diffusing ambient light uniformly and blocking infrared light, improving the accuracy of ambient light sensing in electronic devices.
Implementation Method 1
A light diffuser may be used to diffuse ambient light before the ambient light is measured by the ambient light sensor
Implementation Method 2
The lens layer may be formed from a layer of ultraviolet-light-curable polymer in which an array of lenses has been formed
Implementation Method 3
ambient light sensors may be provided with light diffuser layers that include light-scattering particles
Implementation Method 4
Infrared light in the ambient light measured by the ambient light sensor may be reduced by incorporating an infrared-light-blocking-and-visible-light-transmitting filter structure
Implementation Method 5
The filter structure may be formed as a coating on the ambient light sensor, as a stand-alone filter layer interposed between the diffuser and the ambient light sensor
Implementation Method 6
The lens layer may be formed from a layer of ultraviolet-light-curable polymer in which an array of lenses has been formed
Data Source
AI summary
An electronic device may be provided with a display mounted in a housing. The display may have an array of pixels configured to display images. A display cover layer may overlap the array of pixels. A light sensor such as a color ambient light sensor may be mounted in the electronic device and may receive ambient light through an ambient light sensor window region in the display cover layer or other portion of the electronic device. A diffuser may be located between the display cover layer and the ambient light sensor. The diffuser may have a substrate such as a glass substrate. A lens layer may be supported by the substrate. The lens layer may be formed from a layer of ultraviolet-light-curable polymer in which an array of lenses has been formed. An infrared-light-blocking-and-visible-light-transmitting filter may be used to reduce infrared light reaching the ambient light sensor.