Drug Delivery Pen Zero Position Adjustment via Optical Detection
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Solution Overview
Problem
Current drug delivery devices lack reliable and cost-effective methods for accurately logging and tracking drug delivery data, particularly due to manufacturing tolerances that can lead to inaccuracies in determining the initial position of the scale drum, resulting in incorrect dose measurements.
Innovation Solution
The solution involves providing a pair of zero markers on the housing and scale drum with a predetermined rotational offset, allowing for the detection of the true initial position through image capture and analysis, ensuring accurate dose setting and logging by aligning the scale drum's initial position during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manufacturing tolerances are applied in standard production, then device complexity and manufacturing ease are improved, but measurement precision deteriorates due to scale drum position variation
Solution Approach 1:
The patent replaces manual visual alignment methods with an automated optical detection system. A camera captures images of the scale drum and housing pointer, and image processing algorithms automatically determine the zero position offset, eliminating the need for manual intervention while accommodating manufacturing tolerances.
Solution Approach 2:
The patent changes the approach from assuming a fixed mechanical zero position to dynamically determining the zero position based on detected offset parameters. The system measures the actual offset between the scale drum zero marker and housing zero marker, then uses this parameter to correct dose calculations.
2Measurement precision
If automated image capture and analysis is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the mobile device serve multiple functions: it acts as both the user interface for dose setting and the imaging device for zero position detection. The camera and image processing capabilities of a standard smartphone are leveraged, eliminating the need for dedicated specialized hardware.
Solution Approach 2:
The system uses the patient's existing mobile device, which they already carry and use for other purposes. This eliminates the need for the drug delivery device to include built-in imaging hardware, as the patient's own device provides the necessary functionality.
3Manufacturing precision
If zero markers with predetermined offset are provided, then manufacturing precision requirements are relaxed, but ease of operation decreases due to additional calibration steps
Solution Approach 1:
The patent replaces manual calibration procedures with automated image-based detection. The system automatically captures images of the zero markers, processes them to determine the offset, and applies the correction without requiring the user to perform manual alignment or calibration steps.
Solution Approach 2:
The zero markers are pre-positioned on the scale drum and housing during manufacturing with a predetermined offset. This preliminary action ensures that the markers will be detected correctly by the image processing system, eliminating the need for runtime calibration while maintaining ease of use.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A method of manufacturing a pen drug delivery device comprising the steps of (i) providing a drug delivery device comprising a dose indicator member adapted to move relative to a housing during dose setting and dose expelling corresponding to an axis of rotation, the indicator member having an initial position corresponding to no dose amount being set, (ii) arranging the indicator member in the initial rotational position, and (iii) providing on the housing and on the indicator member respectively a pair of zero markers having a predetermined rotational offset. By this arrangement the issue of finding the correct initial (zero) rotational position of the indicator member is addressed by providing corresponding and rotationally paired zero markings on the pen housing and the indicator member after the pen device has been assembled, this allowing the "true" initial position to be detected by image capture and subsequent image analysis.