Ambient Light Sensor Integration Behind Pixel Array
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Incorporating ambient light sensors into electronic devices is challenging due to space constraints and the potential for stray light interference, which affects the size and appearance of the device.
Innovation Solution
An electronic device with a display that includes an array of pixels, where a subset of pixels overlaps the ambient light sensor to minimize stray light during measurements, allowing the ambient light sensor to gather information while the remaining pixels display images, using control circuitry to adjust display settings based on sensor data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ambient light sensor is incorporated into the electronic device, then the device can detect ambient light conditions and adjust display settings, but the sensor occupies space and may affect the shape and size of the display
Solution Approach 1:
The ambient light sensor is merged with the display structure by positioning it behind the pixel array, allowing the sensor to share the same physical space as the display without requiring additional external space. This integration enables the sensor to detect ambient light through the display pixels while maintaining the display's external dimensions.
Solution Approach 2:
The ambient light sensor is nested within the display structure, specifically positioned behind the pixel array in the display's internal architecture. This nesting allows the sensor to be housed within the existing display volume, eliminating the need for separate sensor housing and preserving display area.
2Area of stationary object
If the ambient light sensor is placed behind the pixel array, then the device appearance is enhanced and space is reduced, but stray light from pixels may interfere with ambient light measurements
Solution Approach 1:
The system employs periodic action by sequentially disabling subsets of pixels during ambient light measurement intervals and re-enabling them for display intervals. This periodic switching between measurement and display modes prevents stray light interference during sensing while maintaining continuous display functionality, thereby ensuring measurement precision without permanently sacrificing display area.
3Loss of information
If all pixels are enabled to display an image, then the display shows complete images, but stray light interferes with ambient light sensor measurements
Solution Approach 1:
The pixel array is segmented into multiple subsets that can be independently controlled. During ambient light measurement, specific subsets of pixels are disabled to eliminate stray light interference, while other subsets remain enabled to maintain partial image display. This segmentation allows selective pixel control, resolving the conflict between complete image display and accurate ambient light measurement.
Solution Approach 2:
The system applies partial action by disabling only the necessary subsets of pixels during measurement intervals rather than all pixels. This partial disabling is sufficient to eliminate stray light interference while minimizing impact on image display completeness. The selective and temporary nature of this partial action allows rapid switching between measurement and display modes.
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 reduces the space occupied by the ambient light sensor, enhances the device's appearance, and effectively adjusts display settings such as brightness and color cast based on ambient light conditions without interfering with image display.
Implementation Method 1
Analog-to-digital converter circuitry can digitize ambient light sensor signals from the floating diffusions for use in producing digital ambient light information
Implementation Method 2
The light-emitting diode may be, for example, an organic light-emitting diode
Implementation Method 3
Each pixel may have an emission enable transistor coupled in series with a light-emitting diode
Data Source
AI summary
An electronic device may have a display with an array of pixels that display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. A subset of the pixels in the array of pixels may overlap the ambient light sensor so that ambient light passing through the subset of pixels may be measured. Each pixel may have an emission enable transistor coupled in series with a light-emitting diode. Control circuitry in the electronic device may disable the subset of pixels to reduce stray light during ambient light measurements while enabling remaining pixels in the array of pixels to display an image. Ambient light sensor circuitry may gather ambient light sensor measurements over one or more periods by using transfer transistors to transfer change from the photodetectors to charge storage capacitors formed from floating diffusions in a common substrate.