Discharge Lamp Driving Device for Projector Electrode Protrusion Melting
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Solution Overview
Problem
Discharge lamps in projectors face issues with reduced protrusion melting at lower drive power, leading to unstable discharge and shorter service life due to wear and tear, which affects illuminance and electrode shape.
Innovation Solution
A discharge lamp driving device with a control unit that adjusts drive frequency and power waveform to maintain stable discharge by increasing power towards refresh power levels and incorporating high-load drive patterns intermittently, based on electrode deterioration, to ensure proper protrusion melting and shape maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If drive power is lowered to extend service life, then electrode load is reduced and service life increases, but protrusion melting is insufficient causing electrode wear and illuminance degradation
Solution Approach 1:
The patent implements periodic action by alternating between low-power mode (for service life extension) and refresh lighting mode (for protrusion melting). The control unit switches between these modes based on lighting duration, ensuring protrusions are melted periodically while maintaining overall low-power operation to extend service life.
Solution Approach 2:
The patent applies preliminary action by performing refresh lighting before the protrusions become severely worn. The control unit detects lighting duration and initiates refresh lighting at appropriate intervals to prevent excessive wear, maintaining protrusion shape and discharge stability proactively rather than reactively.
2Reliability
If lamp power is increased to melt protrusions, then protrusion melting is promoted, but excessive melting occurs causing lamp flicker and crystallization
Solution Approach 1:
The patent utilizes parameter changes by adjusting drive power levels between refresh lighting mode (above rated power for protrusion melting) and low-power mode (below rated power for stable operation). The control unit dynamically switches between these power states to achieve proper protrusion melting without excessive melting that causes harmful effects.
Solution Approach 2:
The patent applies periodic action by implementing refresh lighting only at specific intervals rather than continuously. This periodic refresh prevents excessive melting and harmful effects like lamp flicker and crystallization while still maintaining protrusion shape through regular melting cycles.
3Temperature
If drive frequency is reduced to improve protrusion melting, then melting capability increases, but discharge stability deteriorates
Solution Approach 1:
The patent implements periodic action by alternating between periods of high drive frequency (for stable discharge during low-power mode) and periods of reduced drive frequency (for enhanced protrusion melting during refresh lighting mode). This temporal separation allows both objectives to be achieved without conflict.
Solution Approach 2:
The patent applies preliminary action by establishing stable discharge through high-frequency operation before initiating the protrusion melting process. The control unit ensures discharge stability is maintained during normal operation, then temporarily adjusts frequency to enhance melting during refresh periods.
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 stabilizes discharge, maintains illuminance, and extends the service life of the discharge lamp by ensuring proper melting and shape retention of electrode protrusions, enhancing projector reliability and display quality.
Implementation Method 1
a discharge lamp (90) having a first electrode (92) and a second electrode (93) disposed inside a discharge tube (91)
Implementation Method 2
the protrusions at the distal ends of the electrodes cannot be melted sufficiently
Data Source
AI summary
A discharge lamp driving device includes: a discharge lamp driving unit which supplies drive power to a discharge lamp; and a control unit which controls the discharge lamp driving unit according to a waveform of the drive power. The waveform has n launching periods and a low-power mode lighting period. The n launching periods include a first launching period in which the drive power increases toward refresh power that is equal to or above drive power in a low-power mode and equal to or below rated power, and (n−1) launching periods in which the drive power is maintained at the refresh power. The control unit, in an x-th launching period, supplies the discharge lamp with a drive current having a drive frequency equal to or below a drive frequency of a drive current supplied to the discharge lamp in an (x−1)th launching period.