Gamma Reference Voltage Generator for OLED Display
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Solution Overview
Problem
Existing organic light emitting display devices face degraded display quality due to equally set gamma reference voltages, which do not account for the unique properties of each device, leading to issues like color dragging and first frame response.
Innovation Solution
A digital-analog converter system that determines gamma reference voltages based on the specific properties of the organic light emitting display device by generating a critical voltage through sequential brightness measurement and adding a margin voltage, allowing for adjustable gamma reference voltages for red, green, and blue channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gamma reference voltages are equally set for all devices, then the manufacturing process is simplified, but display quality is degraded due to device property variations
Solution Approach 1:
The patent applies parameter changes by determining gamma reference voltages based on the critical voltage of each display device. Instead of using fixed equal voltage values, the system measures the actual critical voltage of each device and sets the gamma reference voltage accordingly (gamma reference voltage = critical voltage + margin voltage). This allows each device to have customized voltage parameters that match its specific properties, thereby improving display quality while maintaining a relatively simple manufacturing process through automated measurement and calculation.
2Manufacturing precision
If gamma reference voltages are respectively determined based on device properties, then display quality is improved, but the device complexity increases
Solution Approach 1:
The patent implements self-service by enabling each display device to automatically determine its own gamma reference voltage through built-in measurement of its critical voltage. The device measures its own brightness characteristics, calculates its specific critical voltage, and sets its own gamma reference voltage without requiring external calibration equipment or complex manual adjustment processes. This self-determination approach improves display quality while avoiding significant increases in system complexity.
Solution Approach 2:
The system employs feedback mechanisms by measuring the actual brightness output of the display device and using this information to determine the critical voltage. The measured brightness values are fed back to calculate the appropriate gamma reference voltage, ensuring that the final voltage setting accurately reflects the device's actual performance characteristics. This feedback loop enables precise customization of gamma reference voltages without requiring overly complex predetermined lookup tables or calibration procedures.
3Ease of operation
If fixed gamma reference voltages are used, then the system operation is simple, but display faults such as color dragging and first frame response occur
Solution Approach 1:
The patent resolves this contradiction by changing the voltage parameter from fixed to dynamically determined values. The system calculates gamma reference voltages based on each device's measured critical voltage and adds an appropriate margin voltage to prevent display faults. This parameter adjustment ensures that each device operates with optimized voltage levels specific to its characteristics, eliminating color dragging and first frame response issues while maintaining simple operation through automated calculation and application of the determined voltages.
Data Source
AI summary
An organic light emitting display device includes a display panel, a gamma reference voltage generator, and a gamma voltage generator. The gamma reference voltage generator provides the data voltage having a predetermined voltage level to the display panel, changes brightness of the display panel by sequentially reducing the data voltage, determines a critical voltage by comparing a changing amount of the brightness to a predetermined reference changing amount of the brightness, and determines the gamma reference voltage based on the critical.