Electro-optical device variable enable signal control
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Solution Overview
Problem
Existing electro-optical devices struggle to simultaneously adjust display luminance according to environmental brightness and maintain favorable grayscale display, as they either fix maximum luminance or reduce gradations, making it difficult to adapt to varying light conditions.
Innovation Solution
The electro-optical device incorporates digital scanning lines, a digital signal line, and a control line driving circuit that variably sets the enable signal's active period based on grayscale values, allowing the light emitting element to be ON or OFF, thereby adjusting luminance by changing the ratio of ON-state periods within the grayscale display period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If grayscale display is performed by causing the light emitting element to emit light or not emit light for a time period weighted in accordance with each of the bits of the display data, then grayscale display is achieved, but the light emitting luminance at maximum gradation is fixed and cannot be adjusted to match environmental brightness
Solution Approach 1:
The patent introduces a control line driving circuit that dynamically adjusts the active period of enable signals corresponding to different grayscale levels. By making the enable signal active period variable rather than fixed, the system can adapt the display luminance to match environmental brightness conditions while preserving all grayscale gradations. This dynamic control allows the same display device to function optimally in both bright and dark environments.
2Illumination intensity
If the maximum gradation is used as the maximum luminance in bright environment, then display luminance matches bright environment, but in dark environment the maximum luminance cannot be reduced without losing grayscale display quality
Solution Approach 1:
The patent applies different active period ratios of enable signals to different grayscale levels. Specifically, lower grayscale levels (corresponding to darker display requirements) are assigned enable signals with shorter active periods, while higher grayscale levels maintain longer active periods. This local differentiation allows the display to reduce overall luminance in dark environments while preserving the full range of grayscale gradations and their relative relationships.
3Illumination intensity
If a gradation lower than the maximum gradation is used as the maximum luminance in dark environment, then display luminance matches dark environment, but favorable grayscale display cannot be achieved simultaneously
Solution Approach 1:
The patent makes the enable signal active period a variable parameter that can be adjusted based on environmental conditions. The control line driving circuit receives control signals that indicate whether the environment is bright or dark, and accordingly adjusts the active periods of enable signals for all grayscale levels. This universal adjustment mechanism allows the display to maintain favorable grayscale display performance across both bright and dark environments without being limited to a fixed maximum luminance setting.
Data Source
AI summary
An electro-optical device includes a plurality of digital scanning lines, a digital signal line, and a plurality of pixel circuits. Each of the pixel circuits includes a light emitting element and a digital driving circuit. The digital driving circuit performs digital driving to turn the light emitting element ON-state or OFF-state based on a grayscale value. The digital driving circuit keeps the light emitting element ON-state by supplying a drive current to the light emitting element, in a period in which an enable signal is active, of a grayscale display period having a length corresponding to the grayscale value. The control line driving circuit sets a period in which the enable signal is active. A ratio, with respect to the grayscale display period, of an ON-state period in which the light emitting element is ON-state changes in accordance with the period in which the enable signal is active.