Dual-Surface Display Device With Through-Substrate Vias for Low-Frequency Driving
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Solution Overview
Problem
Existing wearable display devices, such as head-mounted displays and augmented reality glasses, face challenges in reducing power consumption while maintaining high resolution, which is essential for long-term user comfort without causing dizziness.
Innovation Solution
The proposed display device incorporates a substrate with a first and second surface, featuring a display panel capable of low-frequency driving. This includes a first driving element layer with a display driving circuit, insulating layers, a light emitting element layer, an encapsulation layer, a second driving element layer with pixel driving circuits connected through through-substrate vias, and a protective layer. The use of oxide semiconductor thin film transistors in the pixel driving circuits enables low-frequency operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high resolution display (2000 PPI or more) is implemented in wearable devices, then user comfort during long-term use is improved, but power consumption increases
Solution Approach 1:
The pixel driving circuit is divided into two separate layers: the first pixel driving circuit layer is formed on the front surface of the substrate, while the second pixel driving circuit layer is formed on the rear surface. This segmentation allows each layer to have optimized transistor designs (oxide semiconductor TFTs in the second layer) that enable low-frequency driving capability, thereby reducing power consumption while maintaining high display resolution
Solution Approach 2:
The pixel driving circuit is extended from a single-layer configuration to a multi-layer configuration by utilizing both the front surface and rear surface of the substrate. The second pixel driving circuit layer on the rear surface connects to the light-emitting element through through-substrate vias, creating a three-dimensional circuit architecture that enables low-frequency operation and reduced power consumption
2Speed
If oxide semiconductor thin film transistors are used in pixel driving circuits, then low-frequency driving capability is improved, but manufacturing complexity increases
Solution Approach 1:
The pixel driving circuit is segmented into two layers with different transistor types: the first layer uses conventional transistors for basic driving functions, while the second layer on the rear surface uses oxide semiconductor thin film transistors specifically for low-frequency operation. This segmentation isolates the manufacturing complexity of oxide semiconductor TFTs to only the second layer, while the first layer can be manufactured using more established processes
Solution Approach 2:
The circuit architecture transitions from a planar single-layer design to a vertical multi-layer design. The second pixel driving circuit layer is positioned on the rear surface of the substrate and connects to the light-emitting element through through-substrate vias, creating a three-dimensional configuration that enables low-frequency driving while distributing manufacturing complexity across different spatial dimensions
Data Source
AI summary
A display device includes a substrate having a first surface and a second surface opposite to each other, a first driving element layer disposed on the first surface of the substrate and including a display driving circuit, at least one insulating layer disposed on the first driving element layer, a light emitting element layer including a light emitting element and disposed on the at least one insulating layer, an encapsulation layer disposed on the light emitting element layer, a second driving element layer disposed on the second surface of the substrate and including a plurality of pixel driving circuits electrically connected to the light emitting element through a first through-substrate via penetrating the substrate, the first driving element layer, and the at least one insulating layer, and a protective layer disposed on the second driving element layer.