Micro-Display Circuit Board Structure for Reliable Flexible Interconnects

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Solution Overview

Problem

The reliability of silicon-based micro-display OLEDs in the AR/VR field is poor due to the use of anisotropic conductive film (ACF) bonding processes in flexible printed circuits (FPCs) for connecting to driving terminals.

Innovation Solution

A circuit board structure with a rigid first circuit board and a flexible second circuit board, where the second circuit board has reduced rigidity for better bending performance, and a metal lead connection between pads, along with a design that includes heat dissipation holes and layers to improve stability and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If a liquid crystal display is used, then power consumption is reduced compared to CRT, but viewing angle is limited and colors appear unnatural when viewed from the side

Engineering Contradiction:
Improvepower consumptionVSAvoidcolor accuracy
Core Design Contradiction:
Use of energy by stationary objectVSIllumination intensity

Solution Approach 1:

The liquid crystal display is divided into multiple sub-pixels (red, green, blue) arranged in a specific pattern, with each sub-pixel controlled independently to enhance color accuracy and viewing angle while maintaining low power consumption

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the display employ different liquid crystal orientations and optical compensation layers tailored to specific viewing zones, ensuring optimal color accuracy and brightness for both front and side viewers without significantly increasing power consumption

Inventive Principle:
Principle #3Local quality

2Speed

If transverse electric field liquid crystals are used, then response speed is fast, but manufacturing precision requirements increase due to alignment sensitivity

Engineering Contradiction:
Improveresponse speedVSAvoidalignment precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

Alignment layers with specific rubbing directions are introduced as intermediaries between the electrode structures and the liquid crystal molecules, providing a robust mechanism to control liquid crystal orientation without requiring extremely precise electrode alignment, thus maintaining fast response while reducing manufacturing precision requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The liquid crystal composition is engineered as a composite mixture of different mesogenic compounds with complementary properties, enhancing the overall response speed and alignment stability, thereby reducing sensitivity to manufacturing variations while maintaining fast switching performance

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If longitudinal electric field liquid crystals are used, then manufacturing is easier, but response speed becomes slow

Engineering Contradiction:
Improvealignment easeVSAvoidresponse speed
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The liquid crystal display employs dynamic voltage control with multiple gray levels and pulse driving schemes, enabling the longitudinal electric field system to achieve faster effective response times while maintaining the manufacturing advantages of vertical alignment

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If pixel density is increased to improve resolution, then display quality improves, but liquid crystal layer thickness must be reduced which slows response speed

Engineering Contradiction:
ImproveresolutionVSAvoidresponse speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent employs advanced liquid crystal materials with optimized elastic constants and dielectric anisotropy parameters, allowing the use of sufficiently thick liquid crystal layers to maintain fast response speeds even at high pixel densities, thus resolving the trade-off between resolution and response speed

Inventive Principle:
Principle #35Parameter changes

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

Enhances the reliability and assembly performance of silicon-based micro-display OLEDs by improving connection stability and reducing thickness while ensuring stable signal transmission and efficient heat dissipation.

Implementation Method 1

a first pixel electrode and a second pixel electrode that define a pixel region in the second substrate, respectively, wherein the liquid crystal molecules are oriented such that a projection of an average molecular long axis onto a plane parallel to the second substrate falls within a range from 5 degrees to 85 degrees

Methodology Applied
Scientific EffectLiquid crystal reorientation: Liquid Crystals

Implementation Method 2

the liquid crystal molecules are oriented such that a projection of an average molecular long axis onto a plane parallel to the second substrate falls within a range from 5 degrees to 85 degrees

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP4132229B1Display module and display device
Publication Date: 2026.05.06 BOE TECHNOLOGY GROUP CO LTD
  • EP4132229B1 patent drawingFigure 1~2
  • EP4132229B1 patent drawingFigure 3~4
  • EP4132229B1 patent drawingFigure 5a~6

AI summary

The embodiments of the present disclosure relate to a display and a display device. The display includes a circuit board structure including a first circuit board and a second circuit board. The first circuit board has a carrying region and an electrical connection region, and a first pad is disposed on the electrical connection region. The second circuit board has a first region and a second region, the first region is arranged on the electrical connection region and is electrically connected to the first pad, and the second region is configured to be electrically connected to the driving terminal. And a rigidity of the second circuit board is less than a rigidity of the first circuit board. The display substrate is located in the carrying region of the first circuit board and includes a silicon substrate, a driving circuit at least partially embedded in the silicon substrate, and a second pad electrically connected to the driving circuit. The driving circuit includes transistor having a semiconductor layer, and the semiconductor layer is located inside the silicon substrate. The second pad is electrically connected to the first pad. The display product of present disclosure has good reliability.