Distance Measuring Sensor Noise Shielding Structure
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Solution Overview
Problem
Time of flight (ToF) sensors in electronic devices are vulnerable to electromagnetic interference (EMI) due to their high TX power operation, which affects the performance of internal electric structures.
Innovation Solution
An electronic device with a noise shielding structure is implemented, featuring a distance measuring sensor housed in a substrate with a shielding sheet attached to the inner surface of the sensor housing, electrically connected to the ground, to minimize electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light emitter operates at high TX power to ensure accurate distance measurement, then the measurement precision is improved, but electromagnetic interference is generated that degrades the performance of internal electric structures
Solution Approach 1:
A shielding sheet is introduced as an intermediary component between the light emitter and the internal electric structures. This shielding sheet acts as a mediator that blocks electromagnetic interference from reaching sensitive components while allowing the high-power light emitter to operate normally for accurate distance measurement
Solution Approach 2:
The harmful electromagnetic interference is extracted and isolated from the internal electric structures through the shielding sheet. By separating the interference path from the sensitive components, the system can maintain both high measurement precision and protected operation of internal structures
2Object-affected harmful factors
If a shielding structure is added to reduce electromagnetic interference, then the harmful effects are reduced, but the device complexity increases
Solution Approach 1:
A thin film shielding sheet is used instead of a bulky shielding structure. This thin film approach provides effective electromagnetic interference protection while minimizing the increase in device complexity and maintaining a compact form factor
Solution Approach 2:
The shielding sheet is nested within the existing sensor housing structure, integrating the shielding function into the existing design rather than adding a separate external shielding layer. This nesting approach reduces overall structural complexity while providing protection
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
The noise shielding structure effectively reduces electromagnetic interference, preventing performance degradation of internal electric structures within the electronic device.
Implementation Method 1
a shielding sheet attached to the inner surface of the sensor housing to surround the distance measuring sensor and electrically connected to a ground disposed to surround the outer periphery of the substrate
Implementation Method 2
a light emitter for emitting a laser light source to the outside
Implementation Method 3
a light receiver for detecting return light emitted from the light emitter and then reflected by an external object
Implementation Method 4
the ToF sensor may measure the distance to an external object by using a time difference (or phase difference) between when light is emitted from the light emitter and when the light is received by the light receiver after being reflected by the external object
Data Source
AI summary
An electronic device is provided. The electronic device includes a housing including a first surface, a second surface facing in a direction opposite to the first surface, and a lateral surface surrounding a space between the first surface and the second surface, a distance measuring sensor disposed in the space between the first surface and the second surface, configured to detect the distance to an external object through the second surface, and including a light emitter and a first light receiver, a substrate on which the distance measuring sensor is disposed, a sensor housing disposed on the substrate, and a shielding sheet attached to the inner surface of the sensor housing to surround the light emitter and the first light receiver and electrically connected to a ground disposed to surround the outer periphery of the substrate.