Discharge Lamp Drive for Projector Posture Adaptability
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Solution Overview
Problem
Conventional projectors using discharge lamps deteriorate when the voltage applying axis is oblique to the horizontal plane, leading to issues like luminance drop, flicker, and instability due to temperature imbalances between electrodes caused by convection from arc discharge.
Innovation Solution
A projector with a discharge lamp drive section that adjusts power supply to maintain electrode temperatures within optimal ranges in both horizontal and vertical postures, using first and second drive powers to stabilize the discharge lamp operation and prevent deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the voltage applying axis of the discharge lamp is kept horizontal to enable projection in various postures, then the projector can be used in both landscape and portrait orientations, but the electrode on the upper side becomes excessively hot and the electrode on the lower side becomes too cold due to convection, causing deterioration
Solution Approach 1:
The patent applies dynamics by making the voltage applying axis rotatable rather than fixed. The discharge lamp's voltage applying axis can be rotated to different angles (e.g., 0° or 90° relative to the optical axis) depending on the projection posture. This dynamic adjustment allows the system to adapt to various installation orientations while maintaining proper electrode temperature distribution, resolving the contradiction between posture adaptability and temperature uniformity.
2Adaptability or versatility
If the voltage applying axis is oriented vertically in portrait mode, then portrait projection is enabled, but the upper electrode melts excessively and the lower electrode becomes unstable, causing luminance drop and flicker
Solution Approach 1:
The patent enables portrait projection capability while maintaining discharge lamp stability through dynamic rotation of the voltage applying axis. When operating in portrait mode, the system rotates the voltage applying axis to be substantially perpendicular to the optical axis (at a predetermined angle such as 90°), which repositions the electrodes to experience more uniform temperature distribution. This dynamic reconfiguration allows portrait projection without the electrode deterioration issues that would occur with a fixed vertical orientation.
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 projector maintains image brightness and stability in both landscape and portrait orientations for a long period by homogenizing electrode temperatures and adjusting power consumption, preventing excessive melting or thinning of electrodes.
Implementation Method 1
the discharge lamp, which emits light due to the arc discharge generated between the pair of electrodes
Implementation Method 2
there occurs convection in the discharge space due to the occurrence of the arc discharge, and the upper side in the vertical direction becomes higher in temperature than the lower side due to the convection
Data Source
AI summary
A projector includes a discharge lamp and a discharge lamp drive section. The discharge lamp drive section is configured to selectively perform a first drive in which first drive power is supplied and a second drive in which second drive power higher than the first drive power is supplied in a first posture, and supply drive power not lower than third drive power and not higher than fourth drive power in a second posture in which optical axis intersects with horizontal plane, the third drive power is drive power with which one of the electrodes in the second posture is set to temperature corresponding to first temperature in the first drive in the first posture, and the fourth drive power is drive power with which one of the electrodes in the second posture is set to temperature corresponding to second temperature in the second drive in the first posture.