Semiconductor Light Emitting Device Display Using Anisotropic Conductive Film

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Solution Overview

Problem

Conventional display devices, such as LCDs and AMOLEDs, face issues with slow response time, high power consumption, and short lifespan due to limitations in semiconductor light emitting devices, particularly in the use of nitride semiconductors for LEDs.

Innovation Solution

A display device utilizing semiconductor light emitting devices with a substrate, anisotropic conductive film, and electrodes to form sub-pixels, where blue semiconductor light emitting devices are used in conjunction with wavelength converting layers and barrier walls to enhance brightness and flexibility, allowing for the creation of red, green, and blue sub-pixels or white sub-pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional LCD devices are used, then display functionality is achieved, but response time is slow and power consumption is high

Engineering Contradiction:
Improveresponse timeVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical liquid crystal switching system with a semiconductor light-emitting system. Each pixel uses a semiconductor light-emitting device that can be directly controlled by electrical signals, eliminating the need for liquid crystal molecules to physically reorient. This substitution of mechanical operation with direct electrical control achieves faster response times and lower power consumption, as semiconductor devices have inherent fast switching characteristics and do not require continuous power to maintain state.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If AMOLED display devices are used, then fast response time is achieved, but reliability is low and lifespan is short due to organic materials

Engineering Contradiction:
Improveresponse timeVSAvoidlifespan
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent changes the material parameter from organic compounds (AMOLED) to inorganic semiconductor materials. By using inorganic semiconductor light-emitting devices with inorganic electrode materials, the display achieves both fast response characteristics of AMOLED and enhanced reliability and lifespan. Inorganic materials are inherently more stable and less prone to degradation over time compared to organic materials, while maintaining the fast switching capability needed for display applications.

Inventive Principle:
Principle #35Parameter changes

3Area of moving object

If semiconductor light emitting devices are made smaller to increase pixel density, then resolution is improved, but alignment precision becomes more difficult

Engineering Contradiction:
Improvepixel sizeVSAvoidalignment precision
Core Design Contradiction:
Area of moving objectVSManufacturing precision

Solution Approach 1:

The patent employs a flexible thin film substrate as the base for mounting semiconductor light-emitting devices. This thin film structure allows for precise positioning and alignment of the small-sized devices while maintaining flexibility in the manufacturing process. The thin film substrate can be precisely patterned and positioned, enabling accurate alignment even when device sizes are reduced to increase pixel density.

Inventive Principle:
Principle #30Flexible shells and thin films

4Illumination intensity

If nitride semiconductor LEDs are used, then high brightness is achieved, but thermal stability issues arise due to heat generation

Engineering Contradiction:
ImprovebrightnessVSAvoidthermal stability
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The patent introduces an intermediary thermal management structure between the nitride semiconductor light-emitting devices and the substrate. This intermediary layer serves as a heat dissipation pathway, conducting heat away from the high-brightness nitride semiconductor devices while allowing the devices to maintain their high brightness output. The intermediary thermal management structure mediates between the high-power light-emitting requirement and the thermal stability requirement.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution enables the creation of high-brightness, flexible display devices with improved reliability and longer lifespan by using small-sized semiconductor light emitting devices and anisotropic conductive films, simplifying the alignment of semiconductor light emitting device arrays and allowing for efficient electrical connections.

Implementation Method 1

an anisotropic conductive film disposed on the substrate provided with the first electrodes

Methodology Applied
Scientific EffectAnisotropic conduction: Anisotropy

Implementation Method 2

Light emitting diode (LEDs) are well-known semiconductor light emitting devices that convert electric current into light

Methodology Applied
Scientific EffectLight emitting diode effect: Light Emitting Diode

Implementation Method 3

semiconductor light emitting devices that convert electric current into light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 4

the wavelength converting layer includes a red fluorescent (phosphor) material and a green fluorescent (phosphor) material constituting individual pixels

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP2888729B1Display device using semiconductor light emitting devices
Publication Date: 2018.09.19 LG ELECTRONICS INC
  • EP2888729B1 patent drawingFigure 1
  • EP2888729B1 patent drawingFigure 2~3
  • EP2888729B1 patent drawingFigure 4~5

AI summary

A display device using a semiconductor light emitting device and a method of fabricating the semiconductor light emitting device are disclosed. The display device includes a substrate, a plurality of first electrodes disposed on the substrate, an anisotropic conductive film disposed on the substrate provided with the first electrodes, a plurality of semiconductor light emitting devices disposed on the anisotropic conductive film layer, electrically connected to the first electrodes, and constituting individual pixels, and a plurality of second electrodes disposed between the semiconductor light emitting devices and electrically connected to the semiconductor light emitting devices. Thus, alignment of the semiconductor light emitting device array may be simplified by use of an anisotropic conductive film. Due to excellent brightness, the semiconductor light emitting devices, which are small in size, may form individual sub-pixels. In addition, the distance between the semiconductor light emitting devices is sufficiently long to embody a flexible display device.