OLED Antireflection Layer Design for External Light Reflection
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Solution Overview
Problem
Existing organic light emitting diode (OLED) display devices face challenges with external light reflection, which reduces visibility and increases power consumption, and the use of polarizers to mitigate this is costly and reduces brightness.
Innovation Solution
An OLED display device with an antireflection layer comprising multiple metallic and insulating layers to minimize external light reflection, combined with a light blocking member made of the same material as the color refiner, which absorbs external light and prevents reflection at the cathode electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizer is used to block external light reflection, then visibility is improved, but brightness transmission decreases to less than 45% and manufacturing cost increases
Solution Approach 1:
The antireflection layer is divided into multiple segments including a first antireflection layer, a second antireflection layer, and a light blocking member. Each layer has specific thickness ranges (e.g., first antireflection layer: 50-200nm, second antireflection layer: 200-500nm) that work together to block external light at different wavelengths and angles, achieving comprehensive reflection protection while maintaining high brightness transmission.
Solution Approach 2:
The patent uses composite material structures where the antireflection layer comprises multiple materials with different optical properties. The first antireflection layer uses materials with refractive indices optimized for specific wavelength ranges, while the second antireflection layer uses different materials to complement the first layer. This composite approach enables broad-spectrum antireflection performance without sacrificing brightness transmission.
2Object-affected harmful factors
If a polarizer is used to block external light reflection, then visibility is improved, but manufacturing cost increases due to the expensive polarizer material
Solution Approach 1:
The patent replaces expensive polarizer materials with cost-effective antireflection layers made from conventional thin film materials. The first and second antireflection layers use materials that can be deposited using standard semiconductor fabrication techniques, significantly reducing manufacturing cost while achieving comparable or superior antireflection performance.
Solution Approach 2:
The patent optimizes the thickness parameters of each antireflection layer to achieve maximum antireflection efficiency. By carefully controlling the thickness of the first antireflection layer (50-200nm) and second antireflection layer (200-500nm), the design achieves broad-spectrum reflection blocking using inexpensive materials, eliminating the need for costly polarizers.
3Illumination intensity
If more power is consumed to compensate for brightness loss from polarizer, then brightness is maintained, but lifetime of the organic light-emitting layer is reduced
Solution Approach 1:
The patent converts the potential harm of external light reflection into a benefit by designing the antireflection layers to selectively block reflected light while transmitting emitted display brightness. The first and second antireflection layers are engineered to have different optical characteristics that allow them to block external light in specific wavelength ranges while maintaining high transmission for the display's emitted light, thereby reducing the need for additional power consumption.
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 effectively reduces manufacturing costs, enhances antireflection efficiency, and minimizes power consumption while improving the lifetime of the organic light emitting layer by maximizing light transmittance and reducing brightness loss.
Implementation Method 1
an antireflection layer formed on the substrate and including at least one metallic layer and at least one insulating layer
Implementation Method 2
a light blocking member on the passivation layer in the non-luminous area... which absorbs external light and prevents reflection
Implementation Method 3
When holes injected from the anode electrode 121 are combined with electrons from the cathode electrode 123, exitons are formed. At this time, light is emitted with a band gap energy of the organic light-emitting layer 122.
Implementation Method 4
The emitted light passes a color refiner 130 and is converted to a desired color.
Implementation Method 5
Light from outside is linearly polarized through the linear polarizer 111, which may be a horizontal linear polarizer. Thus, light from the outside is horizontally polarized (linear).
Implementation Method 6
the linearly polarized light is circularly polarized through the λ/4 phase retarder 113
Implementation Method 7
The circularly polarized light is reflected by the cathode electrode 123 and passes through the λ/4 phase retarder 113 again. When reflected, the left-circularly polarized light is right-circularly polarized.
Data Source
AI summary
An organic light emitting diode display device includes: a substrate defining a plurality of pixels having a luminous area and a non-luminous area; an antireflection layer formed on the substrate and including at least one metallic layer and at least one insulating layer; a thin film transistor formed on the antireflection layer in the non-luminous area and including a gate electrode or a metal line on the antireflection layer in the non-luminous area; a passivation layer formed on the thin film transistor; a color refiner formed on the passivation layer in the luminous area; a light blocking member on the passivation layer in the non-luminous area; an organic light emitting layer; and a cathode and an anode electrodes.