Sensor Module Flow Holes for Blood Pressure Accuracy
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Solution Overview
Problem
The manufacturing process of sensor modules for blood pressure measurement devices is complex and can lead to a decrease in sensor accuracy due to the load exerted on pressure sensors when forming a smooth surface for the soft resin covering, which comes into direct contact with the skin.
Innovation Solution
A sensor module design featuring a sensor base with flow holes extending through the support wall, allowing soft resin to be supplied from the opposite side, reducing the need for pressing a smooth surface and minimizing load on the sensor, while asymmetric and differently sized flow holes facilitate even resin flow and prevent weld line formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If soft resin is injected from the surface side opening and a smooth plate is pressed to form a smooth surface, then the surface smoothness is improved, but the manufacturing process becomes complex and load acts on the pressure sensor
Solution Approach 1:
The patent inverts the conventional injection direction by injecting soft resin from the rear surface side through flow holes instead of from the front surface opening. This reversal eliminates the need for pressing operations to create smooth surfaces, as the resin naturally forms smooth surfaces during injection and curing, thereby simplifying the manufacturing process while maintaining surface quality.
Solution Approach 2:
The patent incorporates flow holes in the rear surface side of the support wall portion before the injection process. This preliminary structural preparation allows the soft resin to be injected directly into the sensor module from the rear side, enabling the resin to flow around the pressure sensor and form smooth surfaces without requiring subsequent pressing operations.
2Manufacturing precision
If a smooth plate is pressed into the opening to form a smooth surface, then the surface smoothness is improved, but sensor accuracy decreases due to load on the pressure sensor
Solution Approach 1:
By inverting the injection direction to enter from the rear surface side, the patent eliminates the pressing operation that causes load on the pressure sensor. The soft resin flows through the flow holes and around the pressure sensor elements, naturally forming smooth surfaces without mechanical pressing, thus preserving sensor accuracy while achieving surface smoothness.
3Ease of manufacture
If flow holes are formed in the support wall portion for resin injection, then the manufacturing process is simplified, but the structure becomes more complex
Solution Approach 1:
The patent segments the support wall portion by forming multiple flow holes at different positions and orientations. This segmentation allows the soft resin to be injected from multiple directions, ensuring complete filling and smooth surface formation around the pressure sensor, while distributing the structural complexity across multiple simple hole features rather than requiring a complex single injection path.
Data Source
AI summary
Provided is a sensor module, a method for manufacturing a sensor module, and a blood pressure measurement device with a highly smooth surface and high sensor accuracy. A sensor module 63 includes: a pressure sensor portion 71; a sensor base 72 including a support wall portion 72a with flow holes 72d to 72g formed extending through the support wall portion 72a from one main surface side to the other main surface side, the pressure sensor portion 71 being disposed on the one main surface side of the sensor base 72; a sensor head cover 73 including an opening 73a at a position opposite a sensor 71a and disposed on the one main surface side of the support wall portion 72a of the sensor base 72 with a gap 79 that communicates with the flow holes 72d to 72g and the opening 73a formed therebetween; and a soft portion 74 disposed in the opening 73a that covers the pressure sensor portion 71.