Display Device Gamma Calculator for Luminance Variation Compensation
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Solution Overview
Problem
Display devices face challenges in minimizing the visibility of luminance changes over time, which affects image quality and user experience due to variations in luminance related to data voltage and driving current.
Innovation Solution
A display device and driving method that include a sensing unit to detect driving current and luminance, a gamma calculator to calculate changed gamma based on these parameters, and a luminance compensator to generate compensated image data by applying corrected gain to grayscale values, ensuring constant luminance variation over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gamma correction is applied to compensate for luminance changes, then image quality is improved, but the system complexity increases due to additional sensing units and calculation circuits
Solution Approach 1:
The patent combines the gamma calculation function with the existing data driver circuitry. The gamma calculator is integrated into the data driver, allowing it to share common circuit resources such as power supply lines, signal transmission paths, and control logic. This merging approach enables gamma correction functionality without proportionally increasing overall system complexity, as the new function utilizes existing infrastructure rather than requiring completely separate dedicated circuits.
Solution Approach 2:
The data driver is designed to perform multiple functions: it serves as both the primary signal transmission circuit for displaying image data and as the gamma calculator for compensating luminance changes. By making the data driver universal and capable of dual functionality, the patent avoids the need for entirely separate gamma correction hardware, thereby improving image quality while minimizing the increase in system complexity through resource sharing.
2Stability of the object's composition
If real-time sensing of driving current and luminance is implemented, then luminance variation is reduced, but the use of energy increases due to continuous measurement and calculation operations
Solution Approach 1:
The sensing unit does not continuously measure driving current and luminance at all times, but rather performs sensing operations periodically or at specific intervals during the display refresh cycle. This periodic sensing approach allows the system to maintain stable luminance characteristics by making necessary measurements only when needed, rather than consuming energy through continuous real-time monitoring, thus balancing luminance stability with energy efficiency.
3Manufacturing precision
If gamma calculation and gain correction are performed for each pixel, then luminance uniformity is improved, but the calculation time increases
Solution Approach 1:
The gamma calculator computes correction values in advance during the vertical blanking interval or other non-display time periods, before the actual image data needs to be displayed. By performing gamma calculation and gain correction computations preliminarily when the display is not actively showing image content, the system achieves accurate per-pixel luminance uniformity without adding calculation time to the critical display path, thus resolving the contradiction between precision and time.
Data Source
AI summary
A display device includes: pixels, each of the pixels including at least one light emitting element and a first transistor configured to supply a driving current to the at least one light emitting element; a sensing unit configured to sense a driving current of the first transistor, which corresponds to a data voltage applied to one pixel from among the pixels, the sensing unit being configured to detect a luminance of the light emitting element, which corresponds to the driving current; a gamma calculator configured to receive the driving current and the luminance of the light emitting element from the sensing unit, to calculate a gamma changed based on the driving current and the luminance of the light emitting element, and to provide, to a memory, the gamma changed based on the driving current and the luminance of the light emitting element.