Flexible Light Shield for Biosensor Stray Light and Pressure
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Solution Overview
Problem
Existing biosensors face issues with stray light interference and component misalignment due to gaps between the casing and substrate, leading to connection errors and measurement defects, especially under external pressure.
Innovation Solution
A biosensor design featuring a flexible light shield member integrated into the housing, which deforms to fill gaps between the circuit board and light emitting/receiving devices, reducing stray light and pressure on the circuit board, thus preventing connection errors and enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rigid optical isolation is disposed between light emitters and light sensors, then stray light is blocked, but the structure deforms under external pressure causing connection errors
Solution Approach 1:
The patent applies a flexible light-shielding film instead of a rigid optical isolation structure. This flexible film can deform under external pressure without causing connection errors, while still maintaining its light-blocking function. The film's flexibility allows it to accommodate structural deformations while preventing stray light from reaching the photodetector.
Solution Approach 2:
The patent changes the physical state of the light-shielding material from rigid to flexible. By selecting a material with appropriate mechanical properties (flexible but light-blocking), the structure can dynamically adapt to pressure changes while maintaining both optical isolation and electrical connection reliability.
2Force
If the housing is pressed during measurement, then external pressure is applied, but the optical isolation deforms causing component misalignment
Solution Approach 1:
The flexible light-shielding film absorbs and accommodates the deformation caused by external pressure. Unlike rigid structures that transmit stress and cause misalignment, the flexible film deforms elastically, maintaining the relative positions of light-emitting and light-receiving components while still blocking stray light.
Solution Approach 2:
The flexible film acts as a cushioning element that preemptively absorbs mechanical stress before it can transmit to the mounted components. This prevents the force from reaching the circuit board and causing connection errors or component misalignment.
3Ease of manufacture
If gaps exist between casing and substrate, then assembly is easier, but stray light passes through disabling the light sensor
Solution Approach 1:
The flexible light-shielding film is designed to conform to the housing interior surface, effectively sealing gaps between the casing and substrate. Its flexibility allows it to adapt to slight variations in assembly tolerances while maintaining continuous light-blocking coverage, preventing stray light from entering the sensor area.
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 flexible light shield effectively blocks stray light and reduces pressure on the circuit board, preventing connection errors and ensuring accurate vital sign measurements without compromising the sensor's structural integrity.
Implementation Method 1
acquire, in the form of a photoelectric pulse signal, a change of the intensity of light that has passed through or that has been reflected off a living body
Implementation Method 2
Existing biosensors known thus far acquire, in the form of a photoelectric pulse signal, a change of the intensity of light
Implementation Method 3
the light shield member having flexibility is deformed by coming into contact with the circuit board, and a gap can be prevented from being formed between the light shield portion and the circuit board, and stray light that is directly incident on the light receiving device from the light emitting device can be reliably blocked
Data Source
AI summary
A photoelectric pulse sensor includes a light emitting device and a light receiving device disposed on a main surface of a circuit board with a predetermined distance apart from each other. A housing is provided to which the circuit board is attached and including a pair of openings respectively corresponding to the light emitting and receiving devices, with the housing including a light shield disposed at least between the pair of openings. The light shield includes a light shield member that is disposed on a surface of the housing facing the circuit board. The light shield member has a light shielding characteristics and flexibility. The light shield member is deformed by coming into contact with the circuit board when the circuit board is attached to the housing.