Display Uniformity Compensation via Time-Divided Modulation
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Solution Overview
Problem
Projection systems using single light valve modulation techniques often experience brightness inconsistencies across the screen, particularly in corner regions, leading to patchy appearances when multiple units are combined, as larger angle lights suffer losses through projection lenses, resulting in lower brightness and uneven color distribution.
Innovation Solution
A method for brightness compensation is implemented by dividing the time period for modulating a frame of image data into two parts, where the full region image data is used for the center region and compensation image data is used for edge regions, adjusting the modulation time to equalize brightness without reducing the dynamic range or grayscale values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the grayscale values in the center region are lowered to reduce image brightness, then the uniformity of display brightness is improved, but the dynamic range of the display is reduced
Solution Approach 1:
The patent divides the display region into a center region and a four-corner region, applying different grayscale adjustment strategies to each segment. The center region grayscale values are reduced to compensate for excessive brightness, while the four-corner region grayscale values are maintained or increased to compensate for brightness loss, thereby achieving uniformity without sacrificing overall dynamic range
Solution Approach 2:
Different grayscale compensation strategies are applied to different spatial regions of the display. The center region receives brightness reduction treatment, while the four-corner regions receive brightness enhancement or maintenance, creating locally optimized quality characteristics for each region based on their specific optical properties
2Area of stationary object
If multiple display units are pieced together to form a display wall, then the display area is expanded, but the brightness and color consistency across units deteriorates
Solution Approach 1:
Each display unit is independently segmented into center and four-corner regions, with customized grayscale compensation applied to each unit. This allows each unit to be optimized individually for uniform brightness distribution, ensuring that when multiple units are combined into a display wall, they maintain consistent brightness and color characteristics across all units
Solution Approach 2:
The patent dynamically adjusts grayscale values as a parameter to compensate for optical losses in different regions. By changing the grayscale parameters specifically for corner regions affected by large-angle light losses, the brightness consistency across multiple display units is maintained while preserving the expanded display area
3Area of stationary object
If large angle lights are transmitted through projection lenses, then the field of view is covered, but light losses occur resulting in lower brightness in corner regions
Solution Approach 1:
The patent recognizes that large-angle light transmission through projection lenses inevitably causes optical losses and reduced brightness in corner regions. Instead of avoiding this, the system accepts the trade-off of covering the full field of view and compensates for the resulting brightness non-uniformity by adjusting grayscale values in the four-corner regions, converting the harmful effect into a manageable parameter through software compensation
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
This approach enhances the uniformity of image brightness across the display unit, ensuring that edge regions have brightness closer to the center regions, thereby improving the overall display effect without compromising the dynamic range or introducing color patches.
Implementation Method 1
a light valve for modulating the red, green and blue lights to generate a light beam representing a color image
Implementation Method 2
a projection lens for projecting the light beam of the color image which has been modulation by the light valve on a screen
Implementation Method 3
the three primary color images are combined into a moving image due to the persistence of vision of human eyes
Data Source
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AI summary
Disclosed are a display uniformity compensation method, an optical modulation apparatus, a signal processor, and a projection system. The method comprises: acquiring original image data and an optical loss coefficient a of a compensation region, acquiring t1 and t2, and making t2/t1 = f a/(1 - a), where 0 < f <= 1, and t1 + t2 = T; determining full region image data and compensation image data through the original image data, t1, t2, and a, within time T when a frame of an image is being modulated, acquiring original light with a period of time t1, and performing modulation on the original light according to the full region image data; and acquiring compensation light within a period of time t2, other than the period of time t1, within the time T, and performing modulation on the compensation light according to the compensation image data. An embodiment of the present invention provides a method for improving a uniformity degree of brightness of an image on a display unit.