OLED Lateral Transport Layers Reduce Light Absorption
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Solution Overview
Problem
The external quantum efficiency of active matrix organic light emitting diode (AMOLED) display devices is low due to significant light absorption and scattering as light passes through multiple layers, leading to reduced light emitting efficiency.
Innovation Solution
The OLED display device structure is optimized by positioning the hole transport layer and electron transport layer on different sides of the luminescent layer, with their vertical projections partially covering the pixel opening area but not overlapping, reducing the number of layers light passes through, and optionally including hole and electron injection layers, anode, and cathode on respective sides, along with electron and hole blocking layers to enhance recombination and reduce absorption and scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If light passes through multiple layers (hole transport layer, electron transport layer, injection layers) to be emitted from the light emitting device, then the device can achieve complete layer coverage and functional completeness, but the light absorption and scattering increase, leading to low external quantum efficiency
Solution Approach 1:
The patent transitions from a conventional vertical stacking arrangement to a lateral arrangement where the hole transport layer and electron transport layer are positioned side-by-side rather than one above the other. This dimensional change allows light to pass through fewer layers in the vertical direction, reducing absorption and scattering losses while maintaining the functional completeness of all necessary layers.
Solution Approach 2:
The patent segments the transport layers into distinct lateral regions - the hole transport layer is positioned in a first region and the electron transport layer in a second region, with their vertical projections not overlapping. This segmentation allows each layer to be optimized independently and reduces the total optical path length through multiple layers.
2Productivity
If the hole transport layer and electron transport layer are positioned on different sides of the luminescent layer with non-overlapping vertical projections, then the light emission efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by assigning different functional regions to different lateral positions - the hole transport layer occupies a first region and the electron transport layer occupies a second region. This spatial differentiation simplifies the manufacturing process by allowing each layer to be deposited with its own optimized parameters and positioning tolerances, rather than requiring precise overlapping of all layers.
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
This configuration improves the external quantum efficiency and light emitting efficiency of the OLED display device by minimizing light loss through reduced absorption and scattering, enhancing the recombination probability of holes and electrons.
Implementation Method 1
the light emitting device comprises: a hole transport layer, a luminescent layer and an electron transport layer
Implementation Method 2
when the light is transmitted in the above mentioned layers, it is partially absorbed and scattered due to the optical waveguide effect
Data Source
AI summary
The embodiments of the present invention provide an organic light emitting diode display device and a method for manufacturing the same. The organic light emitting diode display device comprises: an array substrate comprising a plurality of pixel opening areas; a light emitting device located in each of the pixel opening areas on the array substrate; wherein the light emitting device comprises: a hole transport layer, a luminescent layer and an electron transport layer; wherein a vertical projection of the luminescent layer on the array substrate defines the pixel opening area; the hole transport layer and the electron transport layer are located on different sides of the luminescent layer respectively, or the hole transport layer and the electron transport layer are located on the same side of the luminescent layer; both a vertical projection of the hole transport layer on the array substrate and a vertical projection of the electron transport layer on the array substrate partially cover the pixel opening area; the vertical projection of the hole transport layer on the array substrate and the vertical projection of the electron transport layer on the array substrate do not overlap with each other. The display device and the method for manufacturing the same can reduce the number of the layers required for transmitting the light out of the light emitting device, reducing the loss of the light due to the absorption and scattering of the films; improving the external quantum efficiency of the light emitting device; thereby improving the light emitting efficiency of the display device.