Display Device Current Sensor Luminance Compensation
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Solution Overview
Problem
Organic light emitting display devices face issues with luminance differences between pixel rows due to manufacturing deviations and load mismatches, leading to inconsistent light emission for the same data signal.
Innovation Solution
A display device is designed with a current sensor and timing controller to calculate and compensate for differences in line current between pixel rows, using data signal gain values to ensure equal luminance across all pixel rows by multiplying the converted current values, thereby compensating for input image signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If different numbers of pixels are arranged in different pixel rows, then the display area can be optimized, but luminance differences occur between pixel rows due to load mismatch
Solution Approach 1:
The patent applies local quality by providing different power voltages to different pixel rows based on their specific needs. The first pixel row receives a first power voltage while the second pixel row receives a second power voltage, allowing each row to be optimized for its specific load characteristics and achieve uniform luminance despite having different numbers of pixels
Solution Approach 2:
The patent changes the power voltage parameter to compensate for load differences. By adjusting the power voltage supplied to each pixel row according to the number of pixels it contains, the system maintains uniform luminance across all rows while accommodating varying display area requirements
2Ease of manufacture
If manufacturing deviations in transistors occur, then device production becomes easier, but pixel luminance consistency deteriorates
Solution Approach 1:
The patent implements feedback by measuring the actual line current flowing to each pixel row using current sensors, comparing it with expected values, and then adjusting the power voltage accordingly. This closed-loop control compensates for manufacturing deviations in transistors and ensures consistent pixel luminance across all rows
3Measurement precision
If line current measurement is performed for each pixel row, then luminance compensation accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a current sensor that can measure line current for any pixel row through multiplexing. The same sensor and control circuitry are used to measure currents in different rows at different times, eliminating the need for dedicated sensors for each row and reducing overall device complexity while maintaining measurement precision
Data Source
AI summary
A display device includes: a first pixel row including n pixels coupled to a first scan line; a second pixel row including m pixels coupled to a second scan line; a first power voltage source for supplying a first power voltage to the pixels of the first pixel row and the second pixel row through a first power voltage line; a current sensor for sensing a value of a line current flowing between the first power voltage line and a selected pixel row among the first pixel row and the second pixel row; and a timing controller for calculating a converted current value of the selected pixel row, wherein n is a natural number, and m is a natural number greater than n.