Vertical Stacking of Photodiode and Transistor in Display Substrates
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Solution Overview
Problem
In OLED display substrates, the large area of PIN-type photodiodes used for light-emission detection reduces the aperture ratio, affecting display brightness uniformity and increasing the area occupied by light-emission detection circuitry.
Innovation Solution
The display substrate design includes a PIN-type photodiode and a first control transistor laminated in order away from the base, with the transistor's orthogonal projection overlapping the photodiode's projection, and a light-shielding cathode, to minimize the area occupied by the light-emission detection circuitry while maintaining detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PIN-type photodiode with large area is used for light-emission detection, then detection accuracy is improved, but aperture ratio is reduced and area occupied by detection circuitry increases
Solution Approach 1:
The patent transitions the light-emission detection circuitry from a planar layout to a three-dimensional stacked configuration. The PIN-type photodiode is positioned above the first control transistor in the vertical direction, with their orthogonal projections overlapping on the base. This vertical stacking allows the photodiode to maintain its large detection area while the control transistor occupies overlapping space below, effectively reducing the horizontal footprint and increasing the aperture ratio without compromising detection accuracy.
2Measurement precision
If a PIN-type photodiode with large area is used for light-emission detection, then detection accuracy is improved, but area occupied by detection circuitry increases
Solution Approach 1:
The patent transitions the light-emission detection circuitry from a planar layout to a three-dimensional stacked configuration. The PIN-type photodiode is positioned above the first control transistor in the vertical direction, with their orthogonal projections overlapping on the base. This vertical stacking allows the photodiode to maintain its large detection area while the control transistor occupies overlapping space below, effectively reducing the horizontal footprint and increasing the aperture ratio without compromising detection accuracy.
3Area of stationary object
If the first control transistor and PIN-type photodiode are arranged in overlapping projections, then area efficiency is improved, but structural complexity increases
Solution Approach 1:
The patent implements vertical stacking of the PIN-type photodiode and first control transistor along the direction away from the base, creating an overlapping projection configuration. This three-dimensional arrangement consolidates components that would otherwise occupy separate horizontal spaces, reducing overall circuitry area while the increased structural complexity is managed through standardized fabrication processes for multi-layer device integration.
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 configuration increases the aperture ratio and improves brightness uniformity by reducing the area occupied by the light-emission detection circuitry while ensuring accurate light sensing.
Implementation Method 1
a PIN-type photodiode laminated in that order in a direction away from the base... configured to detect luminescence of light emitted by the light-emitting element
Data Source
AI summary
Provided are a display substrate, a manufacturing method thereof and a display device. The display substrate includes a base and a plurality of subpixels arranged on the base in an array form. Each subpixel includes a light-emitting element, a subpixel driving circuitry coupled to the light-emitting element, and a light-emission detection circuitry configured to detect luminescence of light emitted by the light-emitting element. The light-emission detection circuitry includes a first control transistor and a PIN-type photodiode laminated in that order in a direction away from the base, a first electrode of the first control transistor is coupled to a cathode of the PIN-type photodiode, and an orthogonal projection of the first control transistor onto the base at least partially overlaps an orthogonal projection of the PIN-type photodiode onto the base. The display substrate provided by the present disclosure is used for display.