Proximity Sensor Reference Detector Stray Radiation Timing
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Solution Overview
Problem
Proximity sensors face accuracy and size constraints due to the need for a reference detector to measure the delay between the control signal and radiation emission, which reduces the available radiation for object detection and increases package size, making them less suitable for compact applications like mobile devices.
Innovation Solution
Incorporating a reference detector to receive stray radiation emitted from the radiation source, such as back emission or side emission, to provide a reference signal for accurate time-of-flight calculations, while optimizing the radiation source's design with partially transparent substrates and electrodes to enhance back emission and collect side emissions, thereby reducing package size and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference detector is positioned in the direct path of the main beam to detect radiation emission timing, then the accuracy of time of flight measurement is improved, but the amount of radiation available for transmission and subsequent reflection is reduced
Solution Approach 1:
The patent extracts the reference detector from the direct beam path and positions it to detect only stray radiation. This separation allows the main beam to remain intact for transmission while the reference detector independently measures emission timing using extracted stray radiation components.
Solution Approach 2:
Stray radiation acts as an intermediary between the radiation source and the reference detector. Instead of directly blocking the main beam, the patent uses stray radiation as a mediator to carry timing information to the reference detector, preserving the integrity of the primary beam.
2Measurement precision
If a reference detector is provided as a separate component to detect radiation emission timing, then the accuracy of proximity sensing is improved, but the package size of the sensor is increased
Solution Approach 1:
The patent merges the reference detector with the radiation source assembly, positioning it in close proximity to the VCSEL. This integration allows both components to share a common mounting structure and substrate, significantly reducing the overall package size compared to separate component arrangements.
Solution Approach 2:
The reference detector is nested within the radiation source assembly structure, with both components mounted on the same substrate. This nested arrangement optimizes space utilization and minimizes the overall sensor package footprint.
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 approach enhances the accuracy of proximity sensing by utilizing stray radiation for timing calculations, increases the available radiation for object detection, and reduces the sensor package size, enabling better integration in compact devices like mobile phones and portable devices.
Implementation Method 1
The radiation source 102 emits radiation which is reflected from an object 106 and picked up by detector 104
Implementation Method 2
The reference detector 108 detects radiation generated when the actual output of radiation from the source 102 occurs
Data Source
AI summary
A proximity sensor includes a radiation source configured to emit a primary radiation beam and a primary detector configured to pick up a reflected primary radiation beam. The radiation source is further configured to emit stray radiation. The sensor further includes a reference detector arranged to receive the stray radiation. The stray radiation may, for example, be emitted from either a side of the radiation source or a bottom of the radiation source.