Photosensitive Transistor in AMOLED Array Substrate
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Solution Overview
Problem
The increasing demand for improved display performance in active-matrix organic light-emitting diode (AMOLED) displays leads to a reduction in aperture ratio due to the design of pixel circuits, particularly the via hole arrangement, which affects the overlapping of cathode and anode and reduces capacitor capacity.
Innovation Solution
The arrangement of a photosensitive unit in the light-emitting layer absent regions of sub-pixels, including a photosensitive transistor with its electrodes on a planarization layer, allows for efficient utilization of non-light-emitting regions, enhancing the aperture ratio and enabling compact, efficient circuit design while maintaining light-sensing functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a via hole for overlapping and connecting cathode and anode is filled with pixel definition layer to improve overlapping and prevent short circuiting, then reliability is improved, but aperture ratio is reduced
Solution Approach 1:
The patent relocates the photosensitive transistor from the traditional planar position to a vertical arrangement where the channel region extends through multiple layers (from first electrode layer through pixel definition layer to second electrode layer). This three-dimensional positioning allows the photosensitive function to be integrated without occupying additional lateral space, thereby maintaining aperture ratio while achieving reliable light sensing functionality.
Solution Approach 2:
The patent integrates multiple functions into the via hole structure: it serves as both an electrical connection path (connecting cathode and anode through overlapping) and as a light sensing region (containing the channel region of the photosensitive transistor). This multi-functionality eliminates the need for separate photosensitive regions, preventing aperture ratio reduction while ensuring reliable electrical connections.
2Productivity
If pixels per inch (PPI) is increased to improve display performance, then display performance is improved, but aperture ratio is reduced
Solution Approach 1:
The patent utilizes the vertical dimension by extending the channel region of the photosensitive transistor through multiple layers, thereby utilizing the via hole space three-dimensionally. This allows high PPI design without sacrificing aperture ratio, as the light sensing function is achieved within the vertical stack rather than requiring additional lateral space.
Solution Approach 2:
The patent nests the channel region within the via hole structure, which itself is nested within the pixel structure. The photosensitive channel is embedded within the existing via hole that connects different electrode layers, creating a compact nested arrangement that enables high PPI while maintaining aperture ratio.
3Reliability
If capacitor capacity is increased by adding metal3 layer to improve pixel circuit functionality, then reliability is improved, but aperture ratio is reduced
Solution Approach 1:
The patent extends the capacitor structure vertically by forming the capacitor between the first electrode layer and second electrode layer with the pixel definition layer in between. This vertical stacking approach increases capacitor capacity without occupying additional lateral space, thereby maintaining aperture ratio while improving pixel circuit functionality.
Solution Approach 2:
The capacitor structure is nested within the pixel structure, with the pixel definition layer serving as both the capacitor dielectric and the structural element separating electrode layers. This nested arrangement increases capacitor capacity without requiring additional lateral space that would reduce aperture ratio.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively compensates for the reduced aperture areas in sub-pixels, resulting in more compact and efficient circuits that can sense light, thereby improving the display's performance and aperture ratio.
Implementation Method 1
a photosensitive unit is arranged on each first region and configured to generate an electrical signal based on an intensity of the light being sensed
Data Source
AI summary
The present disclosure relates to an array substrate, a method for manufacturing the array substrate and a display device. The array substrate may include a plurality of pixel groups. Each of the pixel groups may include a plurality of sub-pixels. Each of the sub-pixels may include a light-emitting region and a light-emitting layer absent region. And the light-emitting layer absent regions of the plurality of sub-pixels included in each of the pixel groups may define a first region. A photosensitive unit may be arranged on each first region and configured to generate an electrical signal based on an intensity of the light being sensed.