Jet Pump for Noncontact Tonometry
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Solution Overview
Problem
Conventional noncontact tonometers for measuring intraocular pressure (IOP) are impractical for home use due to their large size, high cost, weight, and power consumption, as well as limited accuracy, making frequent and accurate IOP measurements challenging.
Innovation Solution
A portable jet pump system with a multi-chamber design that generates a controlled air puff using a compression pump, pressure sensors, and a valve to create a desirable pressure profile for noncontact tonometry, eliminating the need for large and heavy piston pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a piston pump is used to generate a fast air puff (20 milliseconds duration), then the required acceleration and coil force increase, but the device size, weight, and cost increase significantly
Solution Approach 1:
The patent replaces the mechanical piston pump system with an electromagnetic speaker driver system. The speaker driver uses electromagnetic force to move a diaphragm, generating the air puff without requiring a mechanical piston, solenoid, or high-force coil assembly. This substitution dramatically reduces the device weight while achieving the required 20-millisecond air puff duration through electromagnetic actuation of the diaphragm.
Solution Approach 2:
The patent uses a flexible diaphragm made of thin film material (such as Mylar or similar polymer) as the moving element. This thin film diaphragm is attached to the speaker driver and forms part of the air seal chamber. The flexibility and lightness of the thin film allow for rapid acceleration and deceleration, enabling the fast 20-millisecond air puff generation without the inertia and weight of metal piston components.
2Power
If a piston pump with large solenoid and high coil force is used, then the air puff generation capability improves, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the complex mechanical piston pump system with a simpler electromagnetic speaker driver system. The speaker driver consists of a voice coil, magnet assembly, and diaphragm - a well-established, simplified configuration compared to piston pumps requiring solenoids, precision-machined cylinders, piston seals, and complex linkages. This substitution reduces both device complexity and manufacturing cost while maintaining the required power output for air puff generation.
Solution Approach 2:
The speaker driver system uses the electromagnetic field generated by the voice coil to directly move the diaphragm, which in turn generates the air puff. The system self-regulates through the natural resonance and mechanical properties of the diaphragm and air chamber, eliminating the need for complex control mechanisms, pressure sensors, and feedback loops required by piston pump systems. This self-service approach simplifies the overall device architecture.
3Productivity
If a piston pump system is used, then the air puff generation is achieved, but the device becomes impractical for home use due to size and portability requirements
Solution Approach 1:
The patent replaces the bulky mechanical piston pump system with a compact electromagnetic speaker driver system. Speaker drivers are inherently compact components designed for space-efficient operation. By eliminating the piston, solenoid, and associated mechanical linkages, the device volume is dramatically reduced, making it suitable for portable handheld configurations that can be easily used at home while maintaining full IOP measurement capability.
Solution Approach 2:
The speaker driver serves multiple functions: it acts as the air pump to generate the air puff, serves as a structural support element for the air seal chamber, and provides a mounting surface for the diaphragm. This multi-functionality reduces the number of separate components needed, thereby reducing overall device volume and making the system more suitable for portable home use while maintaining measurement productivity.
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 jet pump system provides accurate and portable IOP measurements, enabling frequent monitoring at home, reducing the need for clinical visits and improving treatment efficacy by accounting for IOP variations over time.
Implementation Method 1
The compression pump is configured to compress a first volume of gas into the compression chamber
Implementation Method 2
The valve is configured to switch, in response to the first pressure sensor detecting a threshold pressure in the compression chamber, from the closed position to the open position such that the first volume of gas moves from the compression chamber to the surge chamber
Implementation Method 3
a flow-limiting nozzle in communication with the surge chamber, the flow-limiting nozzle comprising a throat having a throat diameter
Data Source
AI summary
Pumps for noncontact tonometry are provided. In one embodiment, a pump for noncontact tonometry includes a compression pump, a compression chamber, a first pressure sensor in communication with the compression chamber, a surge chamber, and a valve separating the compression chamber and surge chamber. The compression pump compresses a first volume of gas into the compression chamber. When the first pressure sensor detects a threshold pressure in the compression chamber, the valve opens and releases the gas into a surge chamber, where it combines with a gas residing in the surge chamber to form a puff of gas that escapes from the surge chamber through a flow-limiting nozzle. The components of the pump, which relies on passive rather than active components to create the controlled puff, can be assembled to have a profile that is portable and fit for home use.