Light Sensor Diffuser and Filter Structures for Ambient Light Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light sensors in electronic devices are prone to inaccuracies due to directional sensitivity, particularly during power-up when pointed at bright or dark sources, leading to inappropriate display brightness adjustments, and are challenging to fabricate with desired tolerances in high-volume manufacturing.
Innovation Solution
The integration of a light diffuser and filter structures, such as a textured surface diffuser and infrared-blocking filter, within the light sensor's optical path to reduce directional sensitivity and mimic the human eye's photopic response, combined with adhesive and optical structures for spectral filtering, helps in accurately measuring ambient light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional light sensors are used without diffuser structures, then the device complexity is reduced, but the measurement precision deteriorates due to directional sensitivity causing inaccurate ambient light readings
Solution Approach 1:
A light diffuser structure is introduced as an intermediary component between the ambient light source and the light sensor. The diffuser scatters incoming light before it reaches the sensor, eliminating directional sensitivity issues. This mediator allows the sensor to accurately measure ambient light levels regardless of the device's orientation or positioning relative to light sources.
2Measurement precision
If light diffuser structures are added to reduce directional sensitivity, then the measurement precision improves, but the device complexity increases due to additional optical components
Solution Approach 1:
The light diffuser function is integrated directly into the light sensor assembly, merging the diffuser component with the sensor housing or mounting structure. This combination approach achieves the desired light scattering effect while minimizing the number of separate components, thereby improving measurement precision without proportionally increasing device complexity.
3Manufacturing precision
If conventional light sensors are used in high-volume manufacturing, then the productivity is maintained, but the manufacturing precision deteriorates due to challenges in achieving desired tolerances
Solution Approach 1:
The light diffuser structure is designed with geometric parameters and material properties that are robust to manufacturing variations. By selecting diffuser materials and configurations that maintain effective light scattering performance across a range of dimensional tolerances, the system achieves consistent measurement precision without requiring extremely tight manufacturing controls, thus supporting high-volume production.
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 the accuracy of ambient light readings by reducing sensor directionality and improving manufacturing tolerances, leading to more precise display brightness adjustments and improved light sensor performance.
Implementation Method 1
Light diffusing structures may be formed from a material that scatters light. For example, a diffuser may be implemented using a transparent structure with a textured surface that scatters light.
Implementation Method 2
A layer of ink or a solid material may be used in forming a filter. Filtering may also be provided by structures associated with a light sensor, by adhesive with filtering properties, by light diffusing structures, by other optical structures, or by combinations of these structures.
Implementation Method 3
A curved surface may be used on a filter, diffuser, or on an integral filter-diffuser to help concentrate incoming light onto the light sensor.
Data Source
AI summary
An electronic device may have a display. The display may have a central active area and a peripheral inactive area. A cover layer such as a layer of cover glass may be used to cover the display. The inner surface of the cover layer in the inactive area may be coated with an opaque masking layer such as black ink. Light for an ambient light sensor or other component may pass through an opening in the black ink. A layer of ink or other structures may be mounted within the opening to serve as a filter structure. A light diffusing structure such as a clear member with a textured surface may be used to diffuse light that is passing through the opening in the black ink and the filter to the light sensor. Integral filter-diffuser structures and structures with concave surfaces for focusing incoming light onto the light sensor may be used.