Projection Display Light Quantity Control for Contrast
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current projection display devices face challenges in enhancing image contrast without increasing cost and size, as existing methods either limit maximum luminance or require multiple light sources, making them impractical for projectors.
Innovation Solution
A projection display device with a light source and multiple light modulating devices, featuring light quantity adjusting devices and a controller unit that adjusts light based on input signals to optimize image contrast, including the use of wavelength-selective polarization changing devices to control light quantity and phase, and a signal correction unit to compensate for light decreases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a color switch is controlled based on average luminance to enhance image contrast, then image contrast is improved, but maximum luminance cannot be attained due to rounding operation
Solution Approach 1:
The patent changes the control parameter from average luminance to maximum luminance. By detecting the maximum luminance value among all input image signals and controlling the color switch based on this maximum value, the system achieves both enhanced image contrast and maintains maximum luminance capability, resolving the contradiction between these two parameters.
2Illumination intensity
If plural LED light sources are used as backlight to enhance image contrast, then image contrast is improved, but cost and size of the display increase
Solution Approach 1:
The patent makes a single light source serve multiple functions by controlling a color switch that can modulate different colors (red, green, blue) based on input image signals. This multi-functional approach enhances image contrast without requiring multiple separate LED light sources, thereby reducing cost and device complexity while maintaining the desired image quality.
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 enhances image contrast while reducing costs and size, allowing for more expressive and high-contrast projections without compromising the quality or longevity of the display.
Implementation Method 1
controlling the transmittance of the color switch based on the resultant average luminance
Implementation Method 2
wavelength-selective polarization changing devices to control light quantity and phase
Data Source
AI summary
In a projection display device which includes a light source for outputting a light and a plurality of light modulating devices for modulating the light from the light source based on an input image signal, the projection display device comprises: a plurality of light quantity adjusting devices disposed on respective incidence sides of the light modulating devices and serving to adjust the quantity of light incident on the respective light modulating devices; and a controller unit for controlling the respective light quantity adjusting devices based on the input image signal.