OLED Sub-Pixel Layout With Hidden Drive Circuits for Higher Transmittance

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Solution Overview

Problem

Existing OLED display panels face challenges in optimizing the layout of pixel driving circuits and light-emitting devices to minimize the exposure of circuit components, which affects light transmittance and increases diffraction, particularly in regions with varying sub-pixel sizes.

Innovation Solution

The display panel design incorporates a layout where the pixel driving circuit is partially or fully hidden under the light-emitting device, with transistors and signal lines arranged to minimize overlap with the light-emitting area, using transparent wiring and via holes to connect signal lines, and optimizing sub-pixel sizes to enhance light transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the pixel driving circuit is arranged separately from the light-emitting device, then the circuit layout is simplified, but the light transmittance decreases and diffraction increases due to exposed circuit components

Engineering Contradiction:
Improvecircuit layout complexityVSAvoidlight transmittance
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The pixel driving circuit is nested under the light-emitting device, with the circuit components (transistors, signal lines) positioned in the region beneath the light-emitting structure. This allows the circuit to be integrated within the overall pixel structure without occupying additional lateral space, thereby maintaining light transmittance while accommodating necessary circuitry.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The circuit components are arranged in the vertical dimension beneath the light-emitting device rather than in the lateral plane. By utilizing the space under the light-emitting structure, the design achieves circuit integration without compromising the light path, effectively moving the circuit from a lateral arrangement to a vertical stacking configuration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If the pixel driving circuit is hidden under the light-emitting device, then light transmittance improves, but the circuit layout becomes more complex and difficult to manufacture

Engineering Contradiction:
Improvelight transmittanceVSAvoidcircuit layout fabrication
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The pixel structure is segmented into distinct functional regions: the light-emitting device in the upper layer and the pixel driving circuit in the lower layer. This segmentation allows independent optimization and fabrication of each region, with the circuit components (first reset transistor, second reset transistor, driving transistor, capacitors) systematically arranged beneath their corresponding light-emitting devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel are assigned different functions and structural characteristics. The region under the light-emitting device is specifically designed to accommodate circuit components, with signal lines and transistors positioned to minimize interference with light transmission while maintaining electrical connectivity. Each sub-pixel's circuit is locally optimized based on its specific requirements.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If sub-pixels have different sizes, then display quality improves, but the layout optimization becomes more difficult and inconsistent

Engineering Contradiction:
Improvedisplay qualityVSAvoidlayout optimization
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The design accommodates asymmetric sub-pixel sizes, with the first sub-pixel having a larger light-emitting area than the second and third sub-pixels. The pixel driving circuit layout is asymmetrically arranged to match the different sizes, with circuit components positioned appropriately under each sub-pixel based on its specific dimensions and requirements.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The design allows variation in key parameters such as light-emitting device area and circuit component dimensions across different sub-pixels. The first sub-pixel's light-emitting device has a larger area, and its corresponding circuit components are sized and positioned differently from those in the second and third sub-pixels, enabling optimization for each specific case.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4468845B1Display panel and display apparatus
Publication Date: 2025.11.26 BOE TECHNOLOGY GROUP CO LTD
  • EP4468845B1 patent drawingFigure 1A~1B
  • EP4468845B1 patent drawingFigure 2A~2B
  • EP4468845B1 patent drawingFigure 3A~3B

AI summary

A display panel. The display panel comprises: a substrate and a plurality of first pixel units. The plurality of first pixel units are located on one side of the substrate, and are distributed in multiple rows and multiple columns, wherein the first pixel units each comprise a plurality of sub-pixels, each sub-pixel comprising a pixel drive circuit and a light-emitting device; the light-emitting device is located on the side of the pixel drive circuit that is away from the substrate, and is electrically connected to the pixel drive circuit; the pixel drive circuit comprises a first reset transistor, a plurality of sub-pixels comprise a first sub-pixel, a second sub-pixel and a third sub-pixel, and the area of a light-emitting device of the first sub-pixel is greater than the area of a light-emitting device of the second sub-pixel, and is greater than the area of a light-emitting device of the third sub-pixel, and an orthographic projection(s) of a first reset transistor in the second sub-pixel and/or a first reset transistor in the third sub-pixel on the substrate is/are located within an orthographic projection of the light-emitting device of the first sub-pixel on the substrate.