High-Pressure Discharge Lamp Lighting Device Noise Control
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Solution Overview
Problem
High-pressure discharge lamp lighting devices produce harsh noise during frequency modulation control, which is undesirable for projectors used in presentations and home theaters, as it affects the listening and viewing experience, and suppressing this noise without compromising the growth and maintenance of electrode protrusions is necessary.
Innovation Solution
Implementing a high-pressure discharge lamp lighting device that controls the frequency modulation of alternating current during a specific period after the starting operation, using a combination of frequencies to minimize noise production while maintaining the shape of electrode protrusions, by selecting specific frequency ranges and intervals for the modulation forbidden period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency modulation control is performed to grow and maintain electrode protrusions, then the arc stability is improved, but harsh noise is produced during the starting operation
Solution Approach 1:
The invention applies preliminary action by performing frequency modulation control during a predetermined period after the starting operation to grow and maintain electrode protrusions before they become deformed. This ensures arc stability is established in advance, preventing flicker and maintaining consistent light output throughout the lamp's operational life.
2Stability of the object's composition
If frequency modulation is applied constantly to maintain protrusion shape, then electrode stability is improved, but noise production increases during operation
Solution Approach 1:
The invention applies periodic action by implementing frequency modulation control only during a specific predetermined period after the starting operation, rather than continuously. This time-limited approach allows protrusions to be grown and maintained when needed for stability, while avoiding noise generation during extended operational periods.
3Manufacturing precision
If frequency modulation control is performed early in the starting operation, then protrusion growth is enhanced, but noise affects the listening experience
Solution Approach 1:
The invention applies preliminary action by concentrating frequency modulation control during an optimal predetermined period after starting operation, when protrusion growth is most critical. This ensures manufacturing precision of the electrode protrusions is achieved during the phase when it matters most, while limiting noise exposure to a controlled time window.
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 reduces noise production without adversely affecting the growth and maintenance of electrode protrusions, improving the quietness of the lighting device and preventing flicker and decline in emitted light, ensuring a stable and quiet operation.
Implementation Method 1
after a high voltage has been applied and a discharge has started (after an electrical breakdown between the electrodes)
Implementation Method 2
a discharge has started between the electrodes
Implementation Method 3
a so-called halogen cycle effect is used to prevent tungsten as a constituent material of the electrodes from being scattered during lighting and adhering to the inner surface of the arc tube
Data Source
AI summary
Constant current control is performed after the completion of starting operation of a high-pressure mercury-vapor lamp 4 and then lighting is shifted to constant power lighting. Except during a modulation forbidden period as a certain period from the completion of the starting operation, the frequency of an alternating current is subjected to frequency modulation control for being modulated to at least a first frequency and a second frequency having higher audibility than the first frequency. During the modulation forbidden period defined as a period from the completion of the starting operation until a predetermined time before lighting is shifted to constant power lighting, from the completion of the starting operation until lighting is shifted to constant power lighting, or from the completion of the starting operation until a predetermined time after lighting has been shifted to constant power lighting, the frequency modulation control is not performed and an alternating current with a third frequency lower than the second frequency is supplied. The quietness can be increased without adversely affecting the frequency modulation control on an alternating current for properly growing and maintaining protrusions of electrodes.