Organic EL Display Flicker Reduction via Segmented Light Emission
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Solution Overview
Problem
Existing methods for reducing flickering in organic EL display devices are ineffective at low frame frequencies, leading to perceived flickering even when power consumption is minimized, as the luminance changes significantly during frame transitions.
Innovation Solution
An organic EL display device with a display panel, transistor, pulse signal generation circuit, and storage unit that manages a frame period with a first light emission period, a black display period, and a second light emission period, where the area product of luminance and duration is greater for the second period than the first, and optionally includes additional light emission periods or varying black display periods to stabilize luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the frame frequency is lowered to reduce power consumption, then power consumption is reduced, but flickering occurs and display quality deteriorates
Solution Approach 1:
The frame period is segmented into multiple light emission periods (first, second, and third light emission periods) separated by a black display period. This segmentation allows the display to maintain multiple light emission events within a single frame period, ensuring that the total light output meets human visual perception requirements even at lower frame frequencies, thereby reducing flickering while maintaining power efficiency
Solution Approach 2:
The patent implements periodic light emission within each frame period through multiple light emission periods. By organizing light emission into regular periodic intervals (first light emission period, black display period, second light emission period, and optionally third light emission period), the display creates a rhythmic pattern that prevents flicker perception while operating at reduced frame frequencies
2Illumination intensity
If the luminance is maintained high throughout the frame period, then display brightness is improved, but power consumption increases
Solution Approach 1:
Instead of maintaining high luminance throughout the entire frame period, the patent applies partial action by providing high luminance only during specific light emission periods (first, second, and third light emission periods) while using a black display period with zero or minimal luminance. This partial application of high luminance satisfies visual perception requirements while significantly reducing overall power consumption
Solution Approach 2:
The patent uses periodic light emission with alternating high-luminance light emission periods and low-luminance black display periods. This periodic pattern allows the display to achieve adequate average brightness for visual perception while minimizing power consumption by keeping the luminance low during the black display period
3Object-affected harmful factors
If a black display period is added to reduce flickering, then flickering is reduced, but the complexity of the driving method increases
Solution Approach 1:
The patent segments the frame period into distinct functional periods (first light emission period, black display period, second light emission period, and third light emission period). This segmentation provides a clear, systematic structure for controlling the display, making the driving method more manageable and less complex by organizing control signals into well-defined temporal segments with specific functions
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 reduces flickering at low frame frequencies while minimizing power consumption by stabilizing luminance changes across the frame period, improving display quality and reducing perceived flicker.
Implementation Method 1
an organic EL display device includes a display panel including a plurality of pixels, each having an organic EL element
Data Source
AI summary
An organic EL display device includes a transistor for controlling whether to shut off supply of a current to an organic EL element or not, a pulse signal generation circuit which generates a pulse signal to be inputted to the transistor and a storage unit. The storage unit stores the information in such a way that one frame period includes, in order, a first light emission period which is a period preceding a pulse, a black display period which is a period equivalent to a width of the pulse, and a second light emission period which is longer than the first light emission period, and that an area expressed by a product of a length of and a luminance in a light emission period is greater for the second light emission period than for the first light emission period.