Projector Light Source Control for Contrast and Power
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Solution Overview
Problem
Projector devices using semiconductor light-emitting elements face challenges in maintaining high contrast due to 'black-floating' issues when the light source is turned off during all-black screens, requiring precise timing for reactivation to avoid missing video parts and increased power consumption.
Innovation Solution
A display apparatus with a determination unit to assess the necessity of light emission and a controller to adjust the emission period, allowing for precise control of light source activation and deactivation based on video signal analysis, reducing power consumption and minimizing video missing during high-contrast projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source is turned off during all-black screens to prevent black-floating and improve contrast, then contrast is improved, but video timing may be missed and reliability deteriorates
Solution Approach 1:
The determination unit predicts whether the light source needs to be emitted in the future based on current video signals, and the control unit activates the light source in advance before actually needed. This preliminary action ensures the light source is ready when video content requires it, preventing timing misses while still allowing the light source to be turned off during all-black periods to maintain high contrast.
2Use of energy by moving object
If the light source is turned off during all-black screens to reduce power consumption, then energy efficiency is improved, but response time increases and productivity deteriorates
Solution Approach 1:
By using the determination unit to predict light source needs in advance and activating the light source before actually required, the system minimizes the light source's off-time. This ensures rapid response when video content changes from black to colored, maintaining high productivity and responsiveness while still achieving significant power savings during extended all-black periods.
3Reliability
If precise timing control is implemented for light source reactivation to prevent video missing, then reliability is improved, but device complexity increases
Solution Approach 1:
The determination unit performs predictive analysis of video signals to anticipate when the light source will be needed, and the control unit activates the light source in advance. This approach simplifies timing control by replacing complex real-time synchronization requirements with a more manageable prediction and advance activation system, improving reliability without excessive complexity increase.
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 'black-floating' and maintains high contrast by optimizing light source usage, reducing power consumption, and ensuring seamless video projection with quick reactivation of the light source during transitions from all-black to colored screens.
Implementation Method 1
a projector device, which employs a semiconductor light-emitting element, such as an LED (light-emitting diode) or an LD (laser diode (semiconductor laser)), as a light source
Data Source
AI summary
According an embodiment, a display apparatus includes a display unit configured to display video corresponding to a video signal which is input, by using light which a light source emits; a determination unit configured to determine, from the video signal, presence/absence of necessity of light emission by the light source at every given time period; and a controller configured to vary and set the time period which is determined by the determination unit, in accordance with a determination result by the determination unit.