Photo-Sensor Sampling Circuit for Ambient Light Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional display devices with photo-sensors struggle to accurately detect ambient light intensity due to variations caused by the driving frequency of fluorescent lamps, leading to inconsistent output.
Innovation Solution
A display device incorporating a photo-sensor, a current sampling unit, and a light detection control unit that samples and averages photocurrent signals over predetermined periods, using edge detection and reset signals to stabilize sampling periods, thereby improving light detection precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photo-sensor is used to detect ambient light, then light detection function is provided, but detection precision deteriorates due to fluorescent lamp frequency variations
Solution Approach 1:
The patent applies periodic action by using a sampling unit to periodically sample the photocurrent at multiple time points and an averaging unit to compute the average over one complete cycle of the fluorescent lamp's driving frequency. This periodic sampling and averaging approach filters out the frequency-related variations caused by the fluorescent lamp, thereby improving both detection precision and output signal stability.
2Measurement precision
If conventional light detection circuit is used, then circuit simplicity is maintained, but detection accuracy deteriorates under fluorescent lighting
Solution Approach 1:
The patent segments the light detection function into three distinct units: a photo-sensor unit for converting light to photocurrent, a sampling unit for periodic photocurrent sampling, and an averaging unit for frequency-based averaging. This segmentation allows each unit to perform its specific function optimally while working together to achieve accurate light detection under fluorescent lighting without excessive overall circuit complexity.
Solution Approach 2:
The sampling unit and averaging unit act as intermediary components between the photo-sensor and the brightness control. These intermediaries process the raw photocurrent signal by sampling and averaging it over the fluorescent lamp's driving cycle, thereby mediating the frequency variation issue and delivering an accurate representation of ambient light intensity to the brightness control system.
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 solution allows for precise detection of ambient light intensity, reducing the impact of fluorescent lamp frequency variations and enabling effective brightness regulation in various lighting environments.
Implementation Method 1
a photo-sensor for detecting ambient light and outputting a photocurrent according to the intensity of the ambient light
Data Source
AI summary
A display device and an electronic apparatus comprising the same are disclosed. The display apparatus includes a photo-sensor for detecting ambient light and outputting a photocurrent according to the intensity of the ambient light, wherein the display apparatus comprises a current sampling unit and a light detection control unit. The current sampling unit is configured to sample the photocurrent outputted from the photo-sensor and to output a plurality of sampling signals to indicate the magnitude of the photocurrent. The light detection control unit is configured to determine an average of the sampling signals outputted from the current sampling unit. The current sampling unit starts a next sampling period corresponding to the end of one of the sampling signals.