Curved Tip Injection Needle for Precise Skin Depth Placement
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Solution Overview
Problem
Existing injection technologies face challenges in accurately inserting needles to a predetermined depth in the skin, particularly with larger diameter needles used for sensor particles, leading to incorrect placement and potential errors in glucose monitoring assays due to the skin's structure and light penetration issues.
Innovation Solution
The development of an injection apparatus with a modified needle tip design where the tip is closer to the longitudinal axis than the outside of the shaft, and a lumen opening length that is 5 to 15 times the shaft diameter, along with a skin positioning member to guide the needle to a specific depth, ensures reliable and accurate injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional needle with tip at the end of shaft is used, then the needle can penetrate the skin, but the injection depth cannot be precisely controlled and the needle may cause excessive stress on the dermis
Solution Approach 1:
The needle tip is positioned closer to the longitudinal axis of the shaft, creating a curved/bent tip configuration rather than a straight end-tip design. This curvature allows the needle to reach the predetermined injection depth more accurately while reducing the linear penetration distance, thereby minimizing stress on the dermis and preventing lesions.
2Illumination intensity
If material is injected into the epidermis, then the sensors can be positioned close to the skin surface for better light detection, but the glucose concentration measurement becomes erroneous due to lack of vasculisation and cell renewal
Solution Approach 1:
The needle is designed with predetermined geometry (tip closer to longitudinal axis) that automatically positions the injection at the correct depth (top of dermis) without requiring active control or feedback during the injection process. This preliminary design ensures sensors are placed in the optimal location for both light detection and accurate glucose measurement.
3Quantity of substance
If a larger diameter needle is used for sensor particles, then the sensors can be injected, but the needle insertion becomes less accurate and may deviate from the intended path
Solution Approach 1:
The needle has non-uniform geometry along its length, with the tip section having different spatial characteristics than the shaft. The tip is positioned closer to the longitudinal axis, creating a localized quality difference that improves insertion accuracy specifically at the critical tip region while maintaining adequate shaft diameter for sensor particle delivery.
Data Source
AI summary
An injection apparatus for making an injection at a predetermined depth in skin comprises: a skin positioning member, an injection needle (610), and means guiding the injection needle for movement from a parking position above the skin beside said skin positioning member to slide beneath said skin positioning member to an injection position; wherein: the tip (620) of the injection needle is closer to the longitudinal axis of the shaft portion (650) than is the outside of the shaft portion (650) and/or the length of the lumen opening (625) of the needle is in a range from 5 to 15 times the diameter of the shaft (650) of the needle. An injection needle wherein the length of the lumen opening (625) of the needle is in a range from 5 to 15 times the diameter of the shaft (650) of the needle.