OLED Gray-Level Compensation for Low-Luminance Image Continuity
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Solution Overview
Problem
OLED displays struggle to express extremely low gray levels due to brightness inconsistencies, leading to inadequate representation of dark areas and unnatural image discontinuities, exacerbated by variations in turn-on levels among different products.
Innovation Solution
A signal processing device that includes a memory to store a reference gray level and a processor to generate a compensation level based on input and reference gray levels, adjusting output signals to improve expressiveness in dark areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the OLED element is turned on to express very dark brightness, then the dark area can be displayed, but the brightness is brighter than the minimum brightness required, causing the dark area to be indistinguishable
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the gray level of the OLED element based on the input gray level. When the input gray level is lower than the reference gray level, the OLED gray level is set to the reference gray level to ensure minimum brightness. When the input gray level is higher, the OLED gray level is adjusted proportionally. This dynamic parameter adjustment resolves the contradiction by ensuring the OLED element can express dark brightness while maintaining distinguishability.
2Manufacturing precision
If the turn-on level for the OLED element is standardized, then mass production consistency can be achieved, but the turn-on level is different for each product, causing variation in dark area expression
Solution Approach 1:
The patent implements feedback by storing a reference gray level that represents the turn-on characteristic of the OLED element. This reference gray level is used to adjust the output gray level based on the input gray level, compensating for variations in turn-on levels across different products. The feedback mechanism ensures that even though manufacturing variations exist, the dark area expression remains consistent across all products.
3Device complexity
If the input gray level is directly output without compensation, then the processing is simple, but the dark area cannot be expressed and image discontinuity occurs
Solution Approach 1:
The patent applies preliminary action by performing gray level compensation before the image signal is output to the display. The processor compares the input gray level with the reference gray level and adjusts the output gray level accordingly. This preliminary adjustment prevents image discontinuity and ensures proper dark area expression before the signal reaches the display, avoiding the need for complex post-processing.
Data Source
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AI summary
A signal processing device for an Organic Light Emitting Diode (OLED) display according to an embodiment of the present disclosure may comprise a memory configured to store a reference gray level, which is a minimum level for turning on an OLED element provided in a pixel or subpixel and a processor configured to obtain an input gray level corresponding to an input image signal, if the obtained input gray level is less than a reference gray level, generate a compensation level based on the input gray level and the reference gray level, obtain an output gray level based on the compensation level, and transmit an output image signal corresponding to the obtained output gray level to a timing controller.