Contactless Ophthalmotonometer Dynamic Current Control for Noise and Precision

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Solution Overview

Problem

Existing contactless ophthalmotonometers generate significant noise due to the driven rotary solenoid, which can discomfort the subject, and reducing the current to the solenoid to minimize noise leads to insufficient air pressure for precise intraocular pressure measurement.

Innovation Solution

A contactless ophthalmotonometer with a current application control unit that applies a first current value to the actuator initially and switches to a higher second current value when a predetermined pressure or displacement threshold is met, ensuring sufficient air pressure without excessive noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the current value applied to the rotary solenoid is reduced to minimize noise, then noise is reduced, but the force to the piston decreases gradually, causing insufficient air pressure for precise measurement

Engineering Contradiction:

ImprovenoiseVSAvoidintraocular pressure measurement precision

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the current value dynamic rather than static. The control unit changes the current value based on the rotation angle of the rotary solenoid: using a first current value for initial rotation (0-θ1) to minimize noise, then switching to a second current value for subsequent rotation (θ1-θ2) to ensure sufficient air pressure. This dynamic adjustment resolves the contradiction between noise reduction and measurement precision.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of current value applied to the rotary solenoid based on the rotation angle. By segmenting the rotation range into two phases and applying different current values to each phase, the system optimizes both noise reduction (in the first phase) and air pressure generation (in the second phase), resolving the technical contradiction.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If a higher current value is applied to the rotary solenoid to maintain sufficient air pressure, then measurement precision is maintained, but noise increases making the subject uncomfortable

Engineering Contradiction:

Improveintraocular pressure measurement precisionVSAvoidnoise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the current value based on the rotation angle to achieve the optimal balance. During the initial rotation phase (0-θ1), a lower current value is applied to minimize noise. When the rotation angle exceeds θ1, the system switches to a higher current value to ensure sufficient air pressure for precise measurement. This dynamic control resolves the contradiction between precision and noise.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements periodic action by dividing the rotation process into distinct phases with different current values. The control unit periodically switches from the first current value to the second current value at a predetermined rotation angle threshold, creating a phased approach that optimizes both noise reduction and measurement precision at different stages of the measurement cycle.

Inventive Principle:

Principle #19Periodic action

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

This approach reduces noise during intraocular pressure measurement while maintaining precision, ensuring comfortable operation and accurate measurement of intraocular pressure.

Implementation Method 1

an actuator configured to move the piston inside the cylinder with current applied to the actuator

Methodology Applied

Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Implementation Method 2

compress air inside the cylinder with the piston

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 3

spray the air compressed with the piston to a subject eye

Methodology Applied

Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentUS20250072753A1Contactless ophthalmotonometer and contactless ophthalmotonometer actuating method

Publication Date: 2025.03.06 TOPCON CORPORATION

AI summary

A contactless ophthalmotonometer includes a cylinder, a piston movably provided inside the cylinder, an actuator (solenoid) configured to move the piston inside the cylinder by applying current to compress air inside the cylinder, a nozzle configured to spray the air compressed with the piston to a subject eye, and a current application control unit (measurement control unit) configured to apply the current to the actuator, wherein the current application control unit performs first application processing for applying the current of a first current value to the actuator and, when a predetermined switching condition is satisfied while the first application processing is being performed, the first application processing is switched to second application processing for applying the current of a second current value higher than the first current value to the actuator.