High-Pressure Discharge Lamp Lighting Device Frequency Control
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Solution Overview
Problem
High-pressure mercury lamps used in liquid crystal projectors face challenges in maintaining long-term stability and brightness due to protuberance growth and contraction at the electrode tips, leading to a drop in luminance and insufficient life span for applications like home theater systems and large-screen displays.
Innovation Solution
A high-pressure discharge lamp lighting device with a frequency controlling unit that varies the alternating current frequency without dependency on operating data, such as voltage, current, or temperature, to maintain the initial form of electrode protuberances and stabilize the discharge region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the frequency of alternating current is kept fixed to maintain stable lighting, then the discharge stability is improved initially, but the protuberances at electrode tips grow excessively over time, causing intensity drop and color instability
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed frequency system to a variable frequency system. The lighting device dynamically adjusts the frequency of alternating current based on the lamp's operating hours, initially using a first frequency to promote protuberance growth and then switching to a second frequency to control excessive growth, thereby extending lamp life while maintaining discharge stability
Solution Approach 2:
The patent implements periodic action by dividing the lamp's operational life into distinct phases with different frequency settings. A frequency control unit switches between a first frequency during initial operation and a second frequency during extended operation, creating periodic cycles of frequency adjustment that prevent protuberance overgrowth and maintain stable discharge characteristics throughout the lamp's life
2Duration of action of moving object
If the frequency of alternating current is varied to control protuberance growth, then the lamp life is extended, but the discharge stability and intensity consistency become difficult to maintain
Solution Approach 1:
The patent implements periodic action by dividing the lamp's operational life into distinct phases with different frequency settings. A frequency control unit switches between a first frequency during initial operation and a second frequency during extended operation, creating periodic cycles of frequency adjustment that prevent protuberance overgrowth and maintain stable discharge characteristics throughout the lamp's life
Solution Approach 2:
The patent applies parameter changes by modifying the frequency parameter of alternating current at different operational stages. The frequency control unit changes the frequency from a first value to a second value based on operating hours, allowing optimization of discharge stability and protuberance control at different phases of lamp life
3Manufacturing precision
If feedback control is used to restore electrode tips by varying frequency based on voltage detection, then protuberance growth is suppressed initially, but the control becomes ineffective in the 2000-3000 hour period when slow size reduction occurs
Solution Approach 1:
The patent applies preliminary action by pre-programming frequency adjustment schedules based on anticipated lamp operating hours. Instead of relying on real-time voltage detection and feedback, the system proactively switches frequencies at predetermined time intervals, ensuring optimal control during the critical 2000-3000 hour period when slow protuberance reduction occurs but voltage-based feedback becomes ineffective
Solution Approach 2:
The patent utilizes feedback by incorporating a detection unit that monitors lamp operating hours and provides information to the frequency control unit. This time-based feedback mechanism enables the system to adjust frequency appropriately at different operational stages, maintaining effective control throughout the lamp's extended life cycle
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 extends the lamp life beyond 3000 hours by maintaining the stability of color reproduction and brightness, suppressing variations in luminance caused by protuberance changes, and ensuring long-term reliability for applications requiring continuous use.
Implementation Method 1
applies a predetermined high voltage pulse to the high-pressure discharge lamp to give dielectric breakdown between the electrodes
Implementation Method 2
causes an alternating current of a predetermined frequency to flow thereby causing the lamp to light
Data Source
AI summary
The high-pressure discharge lamp lighting device of the invention includes a lighting circuit for supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof. A frequency of the alternating current varies without dependency on operating data that varies as a lighting time of the high-pressure discharge lamp elapses.