Discharge Lamp Driving Device Arc Flare Control
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Solution Overview
Problem
Devitrification in discharge lamps reduces illuminance and shortens their service life due to excessive heating of the inner wall, which existing technologies fail to effectively prevent.
Innovation Solution
A discharge lamp driving device that alternates between hybrid periods with varying AC and DC current durations to control the arc flare angle, preventing excessive heating by periodically changing the arc flare angle and its angular velocity, thereby reducing the risk of devitrification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AC current is continuously supplied to the discharge lamp, then the lamp maintains stable operation, but the inner wall of the light emitting tube becomes excessively heated at specific locations causing devitrification
Solution Approach 1:
The patent applies periodic action by alternating between AC current periods and DC current periods with different polarities. During AC periods, the arc flare angle varies periodically, and during DC periods with opposite polarities, the arc flare angle shifts to different positions. This periodic alternation prevents continuous excessive heating at any single location on the inner wall, thereby preventing devitrification while maintaining stable lamp operation.
Solution Approach 2:
The patent employs dynamics by making the arc flare angle variable rather than fixed. By controlling the alternation between AC and DC current periods, the arc flare angle dynamically changes its position and magnitude. This dynamic adjustment ensures that no single location on the inner wall is continuously subjected to maximum heating, thus preventing devitrification while maintaining operational stability.
2Illumination intensity
If the arc flare angle is increased to improve light distribution, then illuminance uniformity improves, but the time required for inner wall heating varies causing devitrification
Solution Approach 1:
The patent uses periodic action by alternating AC and DC current periods to regularly vary the arc flare angle. This periodic variation ensures that different portions of the inner wall are heated for relatively uniform durations over time, preventing localized excessive heating and devitrification while maintaining good illuminance uniformity.
Solution Approach 2:
The patent applies inversion by switching between AC and DC current periods with opposite polarities. This inversion causes the arc flare angle to shift to opposite positions alternately, balancing the heating duration across different inner wall locations and preventing devitrification while maintaining illuminance uniformity.
3Temperature
If DC current with single polarity is supplied to increase arc flare angle, then heating effect is enhanced, but the same location is repeatedly heated causing devitrification
Solution Approach 1:
The patent applies periodic action by alternating between DC periods with opposite polarities. During each DC period, the arc flare angle is enhanced for effective heating, but the polarity alternation ensures that different locations are heated in successive periods. This periodic alternation prevents repeated heating of the same location, avoiding devitrification while maintaining effective heating.
Solution Approach 2:
The patent uses counterweight by applying DC currents with opposite polarities alternately. The first DC period heats one side of the arc flare, while the second DC period with opposite polarity heats the other side. This counterbalancing approach ensures that no single location is repeatedly overheated, preventing devitrification while maintaining overall heating effectiveness.
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 solution effectively prevents devitrification by ensuring uniform heating of the discharge lamp's inner wall, maintaining illuminance and extending the lamp's service life.
Implementation Method 1
a discharge lamp provided with a first electrode and a second electrode
Implementation Method 2
an AC current is supplied to the discharge lamp
Data Source
AI summary
A discharge lamp driving device includes a discharge lamp driving unit configured to supply a driving current to a discharge lamp, and a control unit configured to control the discharge lamp driving unit. The discharge lamp driving device is configured to provide a first hybrid period and a second hybrid period each alternately including a first AC period in which an AC current is supplied and a first DC period in which a DC current with a first polarity is supplied. The control unit, in the first hybrid period, is configured to change a ratio of length of the first DC period to length of the first AC period to be increased, and in the second hybrid period, is configured to change a ratio of the length of the first AC period to the length of the first DC period to be increased.