External Off-Time Pixel Sensing for Display Uniformity
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Solution Overview
Problem
LED electronic displays face non-uniformity issues due to process variations, temperature gradients, and aging, leading to visible anomalies and reduced image quality.
Innovation Solution
Implementing a system that performs display panel sensing to measure operational variations, such as pixel current or voltage, and applies correction values based on lookup tables to adjust image data, ensuring uniformity and improved display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If display panel sensing is performed during active display operation, then real-time compensation can be applied, but power consumption increases and display uniformity may be affected by temporal variations
Solution Approach 1:
The patent implements sensing operations at specific periodic intervals (e.g., during vertical blanking periods or at predetermined time points) rather than continuously. This allows the system to capture temporal variations in pixel characteristics while minimizing power consumption by keeping sensing inactive during normal display operation. The periodic sensing schedule balances real-time compensation needs with energy efficiency.
Solution Approach 2:
The system performs sensing operations in advance during off-time periods before the actual display operation begins. By measuring pixel characteristics during vertical blanking periods or idle intervals, the system prepares compensation data beforehand, ensuring uniformity is maintained during active display while avoiding the power overhead of continuous sensing.
2Measurement precision
If multiple sensing operations are performed across different time intervals, then temporal variations in pixel response can be captured, but measurement complexity and processing requirements increase
Solution Approach 1:
The patent divides the sensing operation into segmented phases: initial sensing during manufacturing calibration, periodic sensing during operation, and on-demand sensing triggered by specific events. Each phase uses simplified measurement procedures appropriate to its context, avoiding the need for complex continuous multi-parameter sensing while still capturing essential temporal variations in pixel response.
Solution Approach 2:
The system uses the display panel's own operational cycles (vertical blanking periods, idle intervals) to perform self-sensing without requiring external testing equipment or complex additional hardware. The existing display driving circuitry is repurposed for sensing operations, reducing overall system complexity while maintaining measurement precision.
3Use of energy by moving object
If pixel sensing is performed during off-time intervals, then power consumption is reduced, but the frequency of compensation updates is limited
Solution Approach 1:
The patent makes the display panel's driving circuitry multi-functional by using the same circuit elements for both normal display operation and sensing operations. During off-time intervals, the circuitry switches to sensing mode without requiring additional dedicated sensing hardware, enabling compensation updates at off-time intervals while maintaining low power consumption. This universal usage of circuitry resolves the trade-off between update frequency and energy efficiency.
4Reliability
If lookup tables are updated frequently with new sensing data, then display uniformity is maintained under changing conditions, but processing time and computational load increase
Solution Approach 1:
The patent implements adaptive update strategies that change the sensing and processing parameters based on operating conditions. During stable conditions, sensing intervals are extended and full lookup table updates are performed less frequently. During transient conditions or when anomalies are detected, the system increases sensing frequency and processes updates more aggressively. This dynamic parameter adjustment maintains uniformity while minimizing unnecessary processing time.
Data Source
AI summary
An electronic device includes a display having multiple regions of pixels. Each pixel includes a diode that emits light based on an amount of current through the diode and a transistor that controls the amount of current flowing through the diode. The electronic device includes driver-integrated circuitry that reduces hysteresis in a first transistor of a first pixel of a region of pixels, settles a threshold voltage of the first transistor, applies a test voltage to the first transistor, and senses a current across the first transistor. The electronic device includes processing circuitry that determines a predetermined voltage based on the current and a predetermined current-voltage relationship determined at an initial temperature, determines a voltage difference between the test voltage and the predetermined voltage, and applies the predetermined voltage and the voltage difference to a second transistor of a second pixel of the region of pixels.