Foot UV Sanitizer Shutter Design for Bulb Life and Ozone Control

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Solution Overview

Problem

Existing ultraviolet light sanitization devices for footwear are prone to premature failure due to frequent power cycles, which reduce the lifespan of the ultraviolet bulbs and are costly to maintain, while ozone production poses health risks and is undesirable for continuous emission.

Innovation Solution

A foot/shoe sanitization system that uses louvers or shutters to selectively occlude ultraviolet light emissions until a user's presence is detected, maintaining continuous power to the ultraviolet bulbs and allowing immediate emission upon user interaction, thereby extending bulb life and controlling ozone production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If ultraviolet bulbs are frequently powered on and off to control ozone production, then ozone exposure is limited to safe levels, but the lifespan of the ultraviolet bulbs is reduced

Engineering Contradiction:

Improveozone exposureVSAvoidbulb lifespan

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The system pre-heats the ultraviolet bulb for a predetermined time period before fully activating it. This preliminary action allows the bulb to warm up gradually, preventing thermal shock and extending bulb lifespan while still controlling ozone production through staged activation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses periodic or pulsed activation of the ultraviolet bulb rather than continuous operation. By controlling the timing and duration of bulb activation, the system limits ozone exposure while reducing the total number of power cycles to extend bulb life.

Inventive Principle:

Principle #19Periodic action

2Productivity

If ultraviolet light is emitted immediately upon user detection, then immediate sanitization is achieved, but ozone production occurs continuously posing health risks

Engineering Contradiction:

Improvesanitization speedVSAvoidozone production

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system activates the ultraviolet bulb in periodic pulses rather than continuous emission. This allows immediate sanitization to begin upon user detection while limiting the total ozone produced during each activation cycle, maintaining safety while preserving effectiveness.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system changes operational parameters by using different power levels or duty cycles for the ultraviolet bulb. By adjusting the intensity and duration of emission, the system achieves rapid sanitization while controlling ozone production to safe levels.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If the ultraviolet bulb is kept continuously powered to extend bulb life, then bulb lifespan is maximized, but ozone is produced continuously which is undesirable

Engineering Contradiction:

Improvebulb lifespanVSAvoidcontinuous ozone production

Core Design Contradiction:

Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The system maintains the ultraviolet bulb in a pre-heated or warm-up state continuously rather than cold-starting it frequently. This preliminary state allows the bulb to be ready for immediate operation while producing minimal ozone during the pre-heated state, extending bulb life without continuous full-power operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous readiness of the ultraviolet bulb through pre-heating, ensuring immediate sanitization capability while using controlled activation periods to limit ozone production. The useful action of sanitization is maintained through rapid response capability rather than continuous full-power operation.

Inventive Principle:

Principle #20Continuity of useful 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

The system extends the life of ultraviolet bulbs by minimizing power cycles and ensures immediate sanitization upon user interaction, while limiting ozone exposure to safe levels.

Implementation Method 1

the optimum range of 250-270 nm has the best potential ability to inactivate microorganisms because it this wavelength is absorbed by nucleic acids of microbial cells

Methodology Applied

Scientific EffectUV-C radiation absorption by nucleic acids: Absorption (EM radiation)

Implementation Method 2

Lower wavelengths of ultraviolet light will ionize oxygen producing ozone (O3)

Methodology Applied

Scientific EffectPhotoionization of oxygen: Photoionisation

Data Source

PatentUS12496366B2Extending UV emitter life

Publication Date: 2025.12.16 HEPCO HLDG LLC

AI summary

A method and apparatus detect the presence of the feet of a user and emits ultraviolet light (and generate ozone) towards the feet of the user when the presence of the feet (e.g., feet or shoes) are detected. To increase the life of ultraviolet emitters within the device and to provide fast response time, the ultraviolet emitters are continuously powered (when a power source is connected). The method and apparatus includes louvers or shutters that move from a closed position to an open position by way of a mechanical linkage upon receiving force from the weight of the user and move from the open position to the closed position upon detecting that the weight of the user abates.