Tunable Filter Ambient Light Sensor for Compact Design
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Solution Overview
Problem
Existing color ambient light sensors for electronic devices face challenges in compact design and accuracy when partially occluded, often consuming excessive space or losing precision.
Innovation Solution
A color ambient light sensor with a tunable wavelength filter, such as an electrically adjustable Fabry-Perot resonator, is integrated into electronic devices, using a light collimator to collimate ambient light and a photodiode to measure the filtered light, while a fixed filter reduces noise, ensuring compactness and immunity to occlusion-induced color inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a color ambient light sensor is designed to be compact, then the device space consumption is reduced, but measurement accuracy may deteriorate
Solution Approach 1:
The patent implements a nested structure where the photodiode is positioned at the focal point of the lens, with the tunable filter and fixed filter arranged in sequence along the optical path. This nested arrangement allows multiple functional components to occupy minimal space while maintaining proper optical alignment, thus achieving compact sensor design without sacrificing measurement accuracy
Solution Approach 2:
The patent uses a tunable filter that can dynamically adjust its transmission wavelength, effectively adding a temporal dimension to the spatial arrangement of optical components. This allows a single filter position to serve multiple wavelength measurement functions, reducing the need for multiple fixed filters and thereby compacting the overall sensor structure
2Volume of moving object
If a color ambient light sensor is designed to be compact, then the device space consumption is reduced, but occlusion resistance may deteriorate
Solution Approach 1:
The patent employs a tunable filter that can dynamically adjust its transmission wavelength in response to different lighting conditions and occlusion scenarios. This dynamic adjustment capability allows the sensor to maintain measurement reliability even when partially occluded, as the filter can be tuned to wavelengths that penetrate or bypass occluding elements, while the compact design is maintained through efficient spatial arrangement
3Adaptability or versatility
If a tunable filter is added to the sensor, then measurement versatility is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal filter structure that can be tuned to different wavelengths to perform multiple measurement functions. The same physical filter component serves various wavelength ranges by adjusting its transmission characteristics, eliminating the need for multiple separate filters. This multi-functionality approach increases versatility while actually reducing structural complexity compared to using multiple fixed filters
Solution Approach 2:
The patent introduces a fixed filter as an intermediary element between the tunable filter and the photodiode. This fixed filter blocks unwanted wavelengths (such as infrared) while allowing the tunable filter to sweep through the visible spectrum. The intermediary fixed filter simplifies the overall system by handling specific wavelength rejection that would otherwise require complex tunable filter configurations
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 enables a compact and accurate color ambient light sensor that effectively measures the ambient light spectrum, allowing for precise adjustments in display brightness and color cast, maintaining performance even when partially occluded.
Implementation Method 1
The color ambient light sensor may have a tunable wavelength filter such as an electrically adjustable Fabry-Perot resonator
Implementation Method 2
A light collimator may be interposed between the display cover layer and the Fabry-Perot resonator to collimate ambient light that is passed to the Fabry-Perot resonator
Implementation Method 3
The control circuitry may use a light detector such as a photodiode to measure the ambient light that has passed through the Fabry-Perot resonator
Implementation Method 4
A fixed filter such as an infrared-light-blocking-and-visible-light-transmitting filter may be interposed between the Fabry-Perot resonator and the photodiode
Data Source
AI summary
An electronic device may be provided with a color ambient light sensor. The color ambient light sensor may be used to measure an ambient light spectrum over a wavelength range of interest. Control circuitry in the electronic device can take actions based on the measured ambient light spectrum such as adjusting the brightness and color cast of content on a display. A display may have a display cover layer. The color ambient light sensor can be mounted under the display cover layer and may receive ambient light through the display cover layer. The color ambient light sensor may have a tunable wavelength filter such as an electrically adjustable Fabry-Perot resonator. A light collimator may be interposed between the display cover layer and the Fabry-Perot resonator to collimate ambient light that is passed to the Fabry-Perot resonator. A light detector measures the light passing through the Fabry-Perot resonator.