Inverted Pixel Structure for Light Emitting Display Voltage Drop
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Solution Overview
Problem
Existing light emitting display devices face challenges in improving display quality due to voltage drop issues caused by threshold voltage and low driving voltage applied to transistors, which affect the performance of light emitting elements.
Innovation Solution
The proposed solution involves a light emitting display device with an inverted pixel structure, where the pixel driving circuit and the cathode of the light emitting element are connected. This structure includes specific transistors and capacitors configured to apply driving voltages effectively, reducing voltage drop and improving current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pixel structure is used, then the device complexity is reduced, but voltage drop occurs causing display quality degradation
Solution Approach 1:
The patent applies inversion by reversing the conventional connection topology: instead of connecting the pixel driving circuit to the anode of the light emitting element, it connects to the cathode. This inverted pixel structure fundamentally changes the voltage application path, allowing the source electrode voltage to be stabilized at a higher potential while the driving voltage is applied through the light emitting element itself, thereby eliminating voltage drop issues without requiring complex additional circuitry.
2Productivity
If threshold voltage is applied to transistors, then the transistor can be turned on, but voltage drop occurs reducing current flow to light emitting element
Solution Approach 1:
By inverting the pixel structure and connecting the pixel driving circuit to the cathode instead of the anode, the patent reverses the voltage drop path. The source electrode of the first transistor is now connected to a high potential driving voltage line, and the voltage drop occurs across the light emitting element rather than being lost in the transistor's source electrode, thereby maintaining higher current flow efficiency to the light emitting element.
Solution Approach 2:
The patent changes the voltage parameters by applying a high potential driving voltage to the source electrode of the first transistor through the inverted connection structure. This parameter change ensures that even when threshold voltage is applied to turn on the transistor, the source electrode maintains a sufficiently high potential to minimize voltage drop and maximize current flow to the light emitting element.
3Illumination intensity
If driving voltage is increased to improve current flow, then luminance improves, but voltage fluctuation in source electrode increases
Solution Approach 1:
The inverted pixel structure stabilizes the source electrode voltage by connecting it directly to a high potential driving voltage line through the cathode connection. This inversion isolates the source electrode from voltage fluctuations that would otherwise occur during switching operations, allowing driving voltage to be increased for improved luminance without causing harmful voltage fluctuations in the source electrode.
Data Source
AI summary
A light emitting display device includes: a light emitting element including an anode connected to a first line; a first transistor; a second transistor including a first electrode connected to a data line, and a second electrode connected to a gate electrode of the first transistor; a third transistor including a first electrode connected to the first line, and a second electrode connected to a first electrode of the first transistor; a fourth transistor including a second electrode connected to the gate electrode; a sixth transistor including a first electrode connected to a second electrode of the first transistor, and a second electrode connected to a second line; a first capacitor including a first electrode connected to the gate electrode and a second electrode connected to the second electrode of the first transistor; and a second capacitor including a second electrode connected to the second electrode of the first transistor.