Projection Display Luminance Control via Phosphor Temperature Feedback
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Solution Overview
Problem
Conventional projection image display devices using light-emitting elements face challenges in maintaining optimal luminance and phosphor durability due to temperature changes, leading to degradation of image quality and increased power consumption, as existing methods fail to effectively control light-emitting output and phosphor deterioration in varying temperature environments.
Innovation Solution
A projection image display device equipped with multiple light sources, a phosphor layer, a temperature detector, a light-source intensity controller, and a luminance controller that adjusts light source intensity and image signal amplitude based on detected temperature to maintain optimal luminance and prevent phosphor deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light-emitting elements are used to obtain high-intensity light source, then luminance is improved, but durability deteriorates due to phosphor deterioration
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the drive current to the light-emitting elements based on detected phosphor layer temperature. When temperature increases, the drive current is reduced to prevent phosphor deterioration, while when temperature decreases, the drive current is increased to maintain luminance. This resolves the contradiction by making luminance and durability parameters interdependent through temperature-based current adjustment.
2Reliability
If climate control is applied to protect light source and phosphors, then durability is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback control by using a temperature detector to monitor phosphor layer temperature and feeding this information back to a luminance controller that adjusts the drive current accordingly. This closed-loop feedback system protects phosphors from excessive temperature without requiring complex climate control mechanisms, resolving the contradiction between durability improvement and device complexity.
3Illumination intensity
If light source intensity is increased to maintain luminance, then luminance is improved, but phosphor deterioration accelerates
Solution Approach 1:
The patent applies dynamics by making the drive current to the light-emitting elements dynamic rather than fixed. The current is continuously adjusted based on real-time temperature detection, allowing the system to optimize between luminance output and phosphor protection. This dynamic adjustment resolves the contradiction by preventing excessive current that would accelerate phosphor deterioration while maintaining adequate luminance.
4Device complexity
If temperature control is not implemented, then device complexity is reduced, but luminance stability deteriorates
Solution Approach 1:
The patent uses feedback control to maintain luminance stability without complex temperature control mechanisms. The temperature detector monitors phosphor layer temperature, and the luminance controller adjusts drive current in response to temperature changes, ensuring stable luminance output. This feedback approach achieves luminance stability with minimal device complexity.
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 device effectively controls luminance and suppresses phosphor deterioration across temperature changes, ensuring consistent image brightness and reduced power consumption by dynamically adjusting light source intensity and image signal amplitude.
Implementation Method 1
a phosphor layer that emits light through excitation by at least any one of the light sources
Data Source
AI summary
A projection image display device has a plurality of light sources, a phosphor layer that emits light through excitation by at least any one of the light sources, an optical section, a temperature detector, a light-source intensity controller, an amplitude controller, a luminance controller. The optical section determines an optical path of light emitted from the light sources and the phosphor layer. The temperature detector directly or indirectly detects temperature of the phosphor layer or of the periphery of the phosphor layer. The light-source intensity controller controls intensity of an excitation light source that excites the phosphor layer. The amplitude controller controls the amplitude of a projection image signal. The luminance controller controls luminance of projection images by switching the light-source intensity controller and the amplitude controller according to a detected temperature.