Discharge Lamp Lighting Device Frequency Control

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Solution Overview

Problem

Existing discharge lamp lighting systems face challenges in efficiently lighting discharge lamps while minimizing power consumption and reducing damage from unstable arc discharges, as they often require continuous frequency changes, leading to increased power consumption and potential lamp damage.

Innovation Solution

The system supplies alternating-current power with a first frequency for resonance and a second frequency equal to or higher than 100 kHz, preventing quasi-resonance states and reducing current values, thereby minimizing power consumption and lamp damage. The second frequency can be set to 170 kHz or lower, and the first frequency is changed stepwise to facilitate resonance, operating the resonance circuit in a capacitive region to prevent backflow currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the frequency of alternating-current power is monotonously increased to resonance frequency to ensure lighting, then the discharge lamp can be lit reliably, but power consumption increases due to quasi-resonance state

Engineering Contradiction:
Improvelighting reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by alternating between resonance frequency supply and non-resonance frequency supply in cycles. The control unit repeatedly supplies power at resonance frequency to enable lighting, then switches to non-resonance frequency to reduce power consumption, creating a periodic pattern that balances reliability and energy efficiency

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by making the frequency supply mode changeable rather than fixed. The control unit dynamically switches between resonance and non-resonance frequency supply based on operational requirements, allowing the system to adapt between lighting reliability mode and power saving mode

Inventive Principle:
Principle #15Dynamics

2Reliability

If alternating-current power is supplied at resonance frequency to light the discharge lamp, then lighting is achieved, but voltage and current in the resonance circuit increase causing higher power consumption

Engineering Contradiction:
Improvelighting achievementVSAvoidvoltage and current in resonance circuit
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The control unit periodically alternates between supplying power at resonance frequency (when lighting is needed) and non-resonance frequency (when power consumption should be reduced), preventing continuous high voltage and current in the resonance circuit while ensuring lighting can be achieved when required

Inventive Principle:
Principle #19Periodic action

3Device complexity

If frequency is fixed when discharge lamp is lit to reduce complexity, then system operation is simplified, but resonance may not occur and lamp may not light

Engineering Contradiction:
Improvefrequency control complexityVSAvoidlighting occurrence
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system dynamically adjusts frequency based on operational phase: during lighting initiation, frequency is varied to achieve resonance and ensure lighting occurs, while during steady-state operation, frequency can be fixed or alternated between resonance and non-resonance values, balancing reliability with simplified control

Inventive Principle:
Principle #15Dynamics

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 configuration reduces power consumption and minimizes damage to the discharge lamp by controlling the frequency of alternating-current power, suppressing voltage and current in the resonance circuit and reducing energy from unstable arc discharges, thus extending the lamp's lifespan.

Implementation Method 1

a high voltage can be obtained by adjusting a frequency of alternating-current power supplied to the discharge lamp to a resonance frequency of the resonance circuit

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2866531B1Discharge lamp lighting device, discharge lamp lighting method, and projector
Publication Date: 2019.10.02 SEIKO EPSON CORP
  • EP2866531B1 patent drawingFigure 1
  • EP2866531B1 patent drawingFigure 2
  • EP2866531B1 patent drawingFigure 3

AI summary

A discharge lamp lighting device according to an aspect of the invention includes a resonance circuit unit connected to a discharge lamp, a power converting unit configured to convert direct-current power into alternating-current power and supply the alternating-current power to the discharge lamp via the resonance circuit unit, and a control unit configured to supply the alternating-current power having a first frequency for causing resonance of the resonance circuit unit and a second frequency different from the first frequency to the discharge lamp in a lighting start period up to time when the discharge lamp reaches a steady lighting state. The second frequency is equal to or higher than 100 kHz.