Optical Sensing Circuit Ambient Light Interference Reduction
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Solution Overview
Problem
The optical sensing circuit is prone to low detection accuracy due to ambient light interference, as high brightness ambient light can mistakenly trigger the circuit, leading to reduced accuracy and increased chances of incorrect triggering.
Innovation Solution
The optical sensing circuit incorporates a first, second, and third optical sensing element, along with a sampling circuit, where the first element raises voltage in response to ambient light and sensing signals, the second element lowers voltage during initialization, and the third element, covered by a filter, transmits currents based on specific color lights to reduce ambient light interference, allowing the sampling circuit to output detection signals based on voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the optical sensing circuit uses a single optical sensing element to detect ambient light, then the circuit structure is simple, but the detection accuracy is low due to high brightness ambient light causing mistaken triggering
Solution Approach 1:
The optical sensing circuit is divided into three separate optical sensing elements (first, second, and third) with distinct functions. The third optical sensing element covered by the filter element specifically detects color light, while the first and second elements handle ambient light compensation and sensing signal generation. This segmentation allows each element to specialize in a specific detection task, improving overall detection accuracy while reducing mistaken triggering from ambient light.
Solution Approach 2:
A filter element is introduced as an intermediary component that selectively transmits color light to the third optical sensing element while blocking other wavelengths. This filter acts as a mediator between the ambient light environment and the sensing element, enabling the circuit to distinguish between relevant color light signals and irrelevant ambient light, thereby improving detection accuracy.
2Measurement precision
If multiple optical sensing elements are used to improve detection accuracy, then the detection accuracy increases, but the device complexity increases
Solution Approach 1:
The three optical sensing elements work together in a coordinated manner where each element contributes to a common sensing objective. The first optical sensing element generates the sensing signal, the second element compensates for ambient light effects, and the third element detects color light. This multi-functional arrangement achieves high detection accuracy through division of labor while maintaining a relatively compact and integrated circuit structure.
Solution Approach 2:
The patent combines multiple optical sensing elements and their associated circuitry into a single integrated optical sensing circuit module. By merging these components into one unified structure, the patent achieves high detection accuracy through multiple sensing elements while avoiding the complexity of separate discrete components, thus resolving the contradiction between accuracy and complexity.
3Measurement precision
If the optical sensing circuit is designed to be sensitive to ambient light for accurate detection, then the detection sensitivity is high, but the circuit is prone to mistaken triggering by high brightness ambient light
Solution Approach 1:
The filter element is applied selectively to the third optical sensing element, creating a localized spectral response characteristic. This filter allows the third element to be highly sensitive to color light wavelengths while being insensitive to other wavelengths present in ambient light. This local quality differentiation enables the circuit to maintain high detection sensitivity for the target signal while rejecting interfering ambient light, thus preventing mistaken triggering.
Solution Approach 2:
The patent converts the harmful effect of ambient light into a beneficial signal by using the first and second optical sensing elements to detect ambient light levels and generate compensation signals. These compensation signals are then used to adjust the output of the third sensing element, transforming the previously harmful ambient light interference into a useful reference for accurate detection and preventing false triggering.
4Measurement precision
If the optical sensing circuit uses filtering to reduce ambient light interference, then the detection accuracy improves, but the device complexity increases
Solution Approach 1:
The filter element is implemented as a thin film structure that is integrated directly over the third optical sensing element. This thin film filter provides selective wavelength transmission without requiring bulky mechanical filter assemblies or complex optical paths. The flexible thin film implementation achieves effective ambient light rejection while maintaining a compact and simple overall circuit structure, thus improving detection accuracy without significantly increasing device complexity.
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 effectively reduces ambient light interference, increases the opening rate of the display area, and enhances sensing speed by accurately distinguishing between ambient light and specific color light inputs, thereby improving detection accuracy.
Implementation Method 1
The first optical sensing element is configured to provide a first current from a first node to a second node in response to the ambient light and a sensing signal during a sensing period
Implementation Method 2
The second optical sensing element is coupled in parallel to the first optical sensing element and configured to draw a second current from the second node to the first node during an initialization period in response to the ambient light and the sensing signal
Implementation Method 3
The third optical sensing element is coupled between the first node and the second node, wherein the third optical sensing element is covered by a first filter element to receive a first color light
Implementation Method 4
the third optical sensing element is covered by a first filter element to receive a first color light
Data Source
AI summary
An optical sensing circuit includes a first, a second, and a third optical sensing element and a sampling circuit. The first sensing element provides a first current from a first node to a second node according to an ambient light and a sensing signal. The second optical sensing element drains a second current from the second node to the first node according to the ambient light and the sensing signal. The third optical sensing element is coupled between the first node and the second node. The third optical sensing element receives a first color light, and transmits the first current to the second node or transmits the second current to the first node according to the first color light. The sampling circuit is turned on according to the sampling signal to output a detection signal based on the voltage level of the second node.