Display Pixel Circuit With Hold Capacitor for Low-Frequency Flicker
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Solution Overview
Problem
Low-frequency driving methods for display devices lead to increased pixel luminance differences between consecutive frames due to leakage currents, which are not effectively addressed by existing technologies.
Innovation Solution
The display device incorporates a unique pixel circuit design with specific channel area widths for switching elements and a hold capacitor to compensate for kickback voltages, reducing leakage currents and maintaining pixel luminance consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If low-frequency driving method is used, then power consumption is reduced, but leakage current increases causing pixel luminance difference
Solution Approach 1:
The patent applies preliminary action by introducing a compensation switching element that proactively compensates for kickback voltage before it can cause significant luminance differences. The holding capacitor stores compensation voltage in advance, and the compensation switching element activates to transfer this voltage to the gate electrode when needed, preventing luminance drift rather than reacting to it after it occurs.
Solution Approach 2:
The patent uses an intermediary approach by introducing a compensation switching element as a mediator between the holding capacitor and the gate electrode. This intermediary component enables controlled voltage transfer from the holding capacitor to compensate for leakage current effects, allowing the system to maintain luminance consistency while operating at low frequencies without directly increasing power consumption.
2Use of energy by stationary object
If low-frequency driving method is used, then power consumption is reduced, but kickback voltage increases affecting pixel performance
Solution Approach 1:
The patent converts the harmful kickback voltage into a beneficial compensation signal. The holding capacitor captures the kickback voltage that would normally be harmful, stores it as compensation voltage, and then uses it to actively compensate for the original kickback effect. This transforms the harmful voltage into a useful compensation mechanism that maintains pixel performance at low driving frequencies.
Solution Approach 2:
The patent implements feedback by using the holding capacitor to store kickback voltage and the compensation switching element to feed this voltage back to the gate electrode. This feedback loop continuously monitors and compensates for voltage drops caused by leakage current, ensuring stable pixel luminance while maintaining low power consumption through the low-frequency driving method.
3Device complexity
If conventional pixel circuit design is used, then device complexity is low, but leakage current cannot be effectively compensated
Solution Approach 1:
The patent merges multiple functions into the pixel circuit by combining the holding capacitor, compensation switching element, and gate electrode into an integrated compensation system. This merged structure allows the pixel circuit to simultaneously perform its basic driving function and the additional function of kickback voltage compensation, achieving luminance consistency with only moderate increases in device complexity.
Solution Approach 2:
The patent applies parameter changes by modifying the gate electrode voltage through the introduction of the compensation switching element and holding capacitor. By dynamically adjusting the gate voltage parameter in response to leakage current effects, the system compensates for luminance differences without fundamentally redesigning the pixel circuit architecture, thus maintaining reasonable device complexity while improving reliability.
Data Source
AI summary
A display device includes a light-emitting element, a driving element to apply a driving current, a 1-1 switching element including a first electrode connected to a gate electrode of the driving element, a gate electrode, and a second electrode connected to a first intermediate node, a 1-2 switching element including a first electrode connected to the first intermediate node, a gate electrode, and a second electrode connected to a second electrode of the driving element, a 2-1 switching element including a first electrode connected to a second intermediate node, a gate electrode, and a second electrode connected to the gate electrode of the driving element, a 2-2 switching element including a first electrode, a gate electrode, and a second electrode connected to the second intermediate node, and a capacitor including a first electrode to receive a power voltage, and a second electrode connected to the first and second intermediate nodes.