TOF Proximity Sensor Module with Segmented Optical Chambers
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Solution Overview
Problem
Integrating a proximity sensor with a small footprint into handheld devices like smartphones is challenging due to space constraints, requiring an efficient and accurate design for proximity detection.
Innovation Solution
A time-of-flight (TOF) sensor module with optically separated light emission and detection channels, where the light emitter and some light sensitive elements are in one chamber, and the rest in another, with an interior wall providing optical isolation, allowing for a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If all light sensitive elements are placed in the light detection chamber, then optical isolation is improved, but the module footprint increases
Solution Approach 1:
The light sensitive elements are segmented into two groups: those that detect emitted light and those that detect reflected light. This segmentation allows the module to maintain optical isolation while reducing footprint by strategically placing different sensor groups in different chambers.
Solution Approach 2:
An optical separator or baffle structure acts as an intermediary element between the light emission chamber and light detection chamber. This intermediary component enables optical isolation while allowing the module to maintain a compact footprint by directing light paths appropriately.
2Area of stationary object
If the module footprint is reduced, then space efficiency is improved, but optical isolation between chambers deteriorates
Solution Approach 1:
The module design transitions from a two-dimensional planar layout to a three-dimensional configuration with multiple chambers stacked or arranged vertically. This dimensional change allows optical isolation to be achieved through spatial separation in the third dimension while maintaining a small footprint in the planar dimensions.
Solution Approach 2:
The light sensitive elements are nested within the chamber structure in a compact arrangement. Some sensors are positioned within the light emission chamber while others are in the detection chamber, creating a nested configuration that maximizes space utilization and maintains optical isolation.
3Measurement precision
If light sensitive elements are placed in both chambers, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The light sensitive elements serve multiple functions: detecting emitted light for reference measurements, detecting reflected light for proximity detection, and enabling both 1D and 3D gesture detection. This multi-functionality improves detection accuracy while avoiding the need for separate dedicated sensor arrays for each function.
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
Enables accurate and quick proximity sensing with a small footprint, suitable for integration into devices with limited space, such as smartphones, while maintaining high accuracy and minimizing spurious reflections.
Implementation Method 1
a light emitter element to generate light, at least some of which is directed out of the module
Implementation Method 2
a time-of-flight sensor including spatially distributed light sensitive elements and including circuitry to read and process signals from the light sensitive elements
Data Source
AI summary
The present disclosure describes proximity sensor modules that include a time-of-flight (TOF) sensor. The module can include a plurality of chambers corresponding, respectively, to a light emission channel and a light detection channel. The channels can be optically separated from one another such that light from a light emitter element in the light emission chamber does not impinge directly on light sensitive elements of the TOF sensor in the light detection chamber. To achieve a module with a relatively small footprint, some parts of the TOF sensor can be located within the light emission chamber.