Radiation Sensor Optical Isolator Proximity Accuracy
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Solution Overview
Problem
Proximity sensors on mobile devices are overly sensitive to minor changes in position, leading to unintended input activation during calls or other operations due to simplistic intensity-based detection methods.
Innovation Solution
A radiation sensor configuration with a first and second detector, an optical isolator, and a cover with directing surfaces that direct radiation from the source to the first detector while preventing propagation between detectors, employing time-of-flight algorithms for improved accuracy and reduced sensitivity to small movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple intensity-based detection method is used, then the device complexity is reduced, but the measurement precision deteriorates due to excessive sensitivity to minor position changes
Solution Approach 1:
The detector is segmented into multiple spatially separated pixels arranged in an array. By analyzing the pattern of light across multiple pixels rather than a single pixel, the system can distinguish between true proximity signals and false signals from minor position changes, thereby improving measurement precision while maintaining relatively simple device architecture
Solution Approach 2:
The system transitions from single-point intensity detection to multi-point spatial distribution detection. By examining the spatial pattern of light across the pixel array, the system gains an additional dimension of information that enables discrimination between actual objects and spurious signals, improving accuracy without significantly increasing device complexity
2Device complexity
If a single detector is used, then the device complexity is reduced, but the reliability deteriorates due to inability to distinguish reference radiation from returned radiation
Solution Approach 1:
The detector is divided into multiple pixels that can be functionally differentiated. Some pixels are designated as reference detectors that receive direct radiation from the source, while others serve as returned radiation detectors. This segmentation enables the system to reliably distinguish between reference and returned signals, improving reliability while maintaining simple overall device structure
Solution Approach 2:
The patent introduces an optical isolator as an intermediary element between the radiation source and the detector array. This optical isolator selectively transmits different portions of radiation to different detector regions, enabling clear differentiation between reference and returned radiation signals without adding significant device complexity
3Ease of operation
If intensity threshold detection is used, then the ease of operation is improved, but the reliability worsens due to false activation during calls from minor hand movements
Solution Approach 1:
By segmenting the detector into multiple pixels with different functional roles (reference vs. returned radiation detectors), the system maintains operational simplicity while eliminating false activations. The segmented architecture allows the system to ignore minor position changes that would not produce the characteristic signal pattern, thereby improving reliability without complicating operation
Solution Approach 2:
The system uses the reference detector pixels to provide feedback about the expected radiation pattern. By comparing the signal from returned radiation detectors against the reference pattern, the system can dynamically distinguish between valid proximity detections and false signals from hand movements, improving reliability while maintaining ease of use
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 proximity sensing, reduces sensitivity to minor movements, and allows for more detailed information about object distance, such as in mobile phone applications, by using time-of-flight algorithms and optical isolation to prevent false signals.
Implementation Method 1
emitting, typically, light from the radiation source
Implementation Method 2
the optical isolator is configured to impede the propagation of radiation between the first radiation detector and the second radiation detector
Implementation Method 3
the radiation source and at least one directing surface are together arranged to direct a portion of radiation emitted by the radiation source onto the first radiation detector
Data Source
AI summary
A radiation sensor of the type having a packaged radiation source and detector, which includes an isolator that blocks propagation within the package of radiation from the source to the detector, in order to improve signal to noise ratio of the sensor. The isolator is formed by appropriately formed surfaces of the package.