Integrated LED Display with CMOS Driver and Oxide Semiconductor Switches

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Solution Overview

Problem

Current LED displays, particularly in VR applications, face challenges in achieving high image resolution and response speed while maintaining a compact size, with TFTs struggling to support the demands for high-resolution and high-refresh-rate displays.

Innovation Solution

An integrated LED display is fabricated using a CMOS wafer with a driver circuitry, a conductive semiconductor layer, and a high-speed switch device array comprising oxide semiconductor field effect transistors, which improves the driving capability and allows for high-density, high-speed operation of LED devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If LED device size is reduced to achieve higher image resolution, then image resolution is improved, but response speed deteriorates

Engineering Contradiction:

Improveimage resolutionVSAvoidresponse speed

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The patent changes the material parameter of the transistor from conventional TFT to oxide semiconductor transistor, which fundamentally alters the electrical characteristics and enables high-speed operation in miniaturized LED devices

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure combining oxide semiconductor layer with metal electrodes (Al, Mo, W, TiN, etc.) to create a transistor that achieves both miniaturization and high-speed performance

Inventive Principle:

Principle #40Composite materials

2Device complexity

If TFT is used to drive LED device, then device complexity is reduced, but driving capability deteriorates

Engineering Contradiction:

Improvedriving circuit simplicityVSAvoiddriving capability

Core Design Contradiction:

Device complexityVSPower

Solution Approach 1:

The patent changes the transistor type from TFT to oxide semiconductor transistor, which provides superior driving capability with higher current drive strength and faster switching speed while maintaining circuit simplicity

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If LED array density is increased for high resolution display, then image resolution is improved, but weight of VR apparatus increases

Engineering Contradiction:

Improveimage resolutionVSAvoidVR apparatus weight

Core Design Contradiction:

Manufacturing precisionVSWeight of moving object

Solution Approach 1:

The patent uses oxide semiconductor transistor technology that enables higher LED density integration, allowing more LEDs to be packed into the same area without proportionally increasing overall device weight

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent transitions from planar LED arrangement to three-dimensional stacked structure with multiple LED layers, achieving high resolution by utilizing vertical space rather than only horizontal expansion

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10354580B2Integrated LED display and fabrication method thereof

Publication Date: 2019.07.16 UNITED MICROELECTRONICS CORP

AI summary

An integrated LED display is provided. The integrated LED display includes a complementary metal-oxide-semiconductor (CMOS) wafer including a driver circuitry fabricated on a substrate. Further, an insulating layer is disposed over the CMOS wafer. A conductive semiconductor layer is disposed on the insulating layer. A LED array is disposed on the conductive semiconductor layer and the LED array connected to the driver circuitry. The LED array includes a photo device array, disposed on the conductive semiconductor layer, and a switch device array, disposed on the conductive semiconductor layer.