Discharge Lamp Lighting Apparatus Current Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Xenon discharge lamps designed to maintain low cathode electrode temperature for longer lifespan face issues with bulb blackening due to inadequate heat dissipation and electron emission, leading to reduced color reproduction and image quality in projectors.
Innovation Solution
A discharge lamp lighting apparatus with an output current modulation circuit that controls the change speed of lamp current to 3.9 A per millisecond or less and a rush current supply unit providing pulses of 22 A or less per square millimeter, ensuring optimal heat management and electron emission distribution to prevent bulb blackening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the cathode electrode temperature is reduced to extend lamp lifespan, then electron emission efficiency improves, but heat dissipation becomes insufficient causing bulb blackening
Solution Approach 1:
The patent applies periodic action by implementing a rush current supply unit that provides periodic high-current pulses during startup phases. These pulses temporarily increase cathode temperature to enable proper electron emission and prevent blackening, then switch to normal operating current that maintains lower temperature for extended lifespan. This periodic switching between high-current startup mode and low-current operation mode resolves the contradiction between lifespan extension and blackening prevention.
Solution Approach 2:
The patent changes the current parameter dynamically through an output current modulation circuit that controls the change speed of lamp current. By adjusting current magnitude and rate of change based on operational phase (startup vs. steady-state), the system optimizes cathode temperature to prevent blackening during startup while maintaining low temperature during operation for extended lifespan.
2Speed
If the lamp current increases rapidly to improve response time, then lighting speed improves, but cathode electrode damage occurs due to excessive heat
Solution Approach 1:
The patent applies preliminary action by providing a rush current pulse before normal operation begins. This preliminary high-current pulse prepares the cathode electrode by initializing electron emission and establishing proper thermal conditions, preventing damage when subsequent current increases occur. The modulation circuit then controls the rate of current increase to prevent excessive heating while maintaining fast response.
Solution Approach 2:
The patent implements dynamics through an output current modulation circuit that dynamically adjusts the lamp current based on operational requirements. The circuit controls the change speed of current to optimize both response time and electrode protection, switching between different current levels and rates of change depending on whether the system is in startup, steady-state, or modulation phase.
3Temperature
If the anode electrode size is increased to improve heat dissipation, then thermal management improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces the mechanical/structural solution of enlarging the anode electrode with an electrical solution. Instead of increasing physical size for heat dissipation, the system uses electronic control of current magnitude and rate of change to manage thermal load on the cathode electrode, maintaining simple electrode geometry while achieving effective thermal management through intelligent power delivery.
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 bulb blackening and maintains image quality by managing heat dissipation and electron emission, extending the lifespan of xenon discharge lamps while ensuring stable arc discharge and improved color reproduction.
Implementation Method 1
a starter which generates high voltage at initiation so as to generate dielectric breakdown in the discharge container of the discharge lamp
Implementation Method 2
at least a cathode electrode thereof contains electron emission nature substance
Implementation Method 3
arc discharge is generated between these electrodes
Implementation Method 4
the power supply circuit has an output current modulation circuit which modulates a magnitude of current flowing through the discharge lamp
Data Source
AI summary
In a discharge lamp lighting apparatus for lighting a discharge lamp comprises a starter which generates high voltage at initiation so as to generate dielectric breakdown in the discharge container of the discharge lamp; and a power supply circuit which supply discharge current to the discharge lamp, wherein the power supply circuit has an output current modulation circuit which modulates a magnitude of current flowing through the discharge lamp at least in a steady state, wherein the output current modulation circuit controls a change speed in case a lamp current per square millimeter in a cross section of the cathode electrode is increased, to be 3.9 A per millisecond or less, wherein the power supply circuit carries out control in which an average current in the steady state is set so that an odd-shape portion is formed at a tip of the cathode electrode.