Convex-Concave Light-Emitting Element for Display Device
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Solution Overview
Problem
Existing display devices face challenges in improving light extraction efficiency from light-emitting elements and controlling liquid crystal layers while maintaining low power consumption.
Innovation Solution
A display device structure featuring a light-emitting element with a convex-concave shape and a reflective liquid crystal element, where the light-emitting element is electrically connected to a first transistor and the liquid crystal element to a second transistor through a reflective electrode, allowing for enhanced light extraction and independent control of the liquid crystal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common signal line and shared TFT are used between light-emitting element and optical modulation element, then device complexity and cost are reduced, but independent control capability and light extraction efficiency are compromised
Solution Approach 1:
The patent divides the control system into separate transistors: a first TFT controls the light-emitting element while a second TFT controls the liquid crystal element. This segmentation allows independent optimization of each control path, enabling precise control of light extraction through the liquid crystal layer while maintaining simple device structure. The separation resolves the contradiction by providing independent control capability without significantly increasing overall device complexity.
Solution Approach 2:
The patent introduces a vertical stacking dimension by placing the light-emitting element and liquid crystal element in different layers along the light path direction. The light-emitting element is positioned in a first layer while the liquid crystal element is in a second layer, with the light-emitting element overlapping the transparent region of the liquid crystal element. This dimensional arrangement enables independent control of light emission and light modulation functions while maintaining a compact structure.
2Use of energy by moving object
If the organic EL element area is reduced to match the transparent region area, then power consumption is reduced, but light extraction efficiency is not optimized
Solution Approach 1:
The patent applies local quality by making the light-emitting element area substantially equal to or smaller than the transparent region area of the liquid crystal element. This localized matching ensures that light is emitted only where it can be effectively extracted through the transparent region, minimizing energy waste in regions where light cannot pass through. The controlled area relationship optimizes both power consumption and light extraction efficiency simultaneously.
Solution Approach 2:
The patent introduces the liquid crystal element as an intermediary between the light-emitting element and the external environment. The liquid crystal layer with its transparent region acts as a mediator that controls light extraction, allowing the light-emitting element to operate at reduced area while maintaining efficient light output through the controlled transparent region. This intermediary enables precise control of the light emission-extraction process.
3Use of energy by moving object
If a reflective liquid crystal element is used, then power consumption is reduced, but control capability over light emission is limited
Solution Approach 1:
The patent employs dynamic control by using a second TFT that can independently modulate the liquid crystal element's state. The liquid crystal element can switch between different orientations (vertical alignment for black display, horizontal alignment for white display) under controlled voltage application. This dynamic control capability allows precise regulation of light extraction from the light-emitting element while maintaining the low power consumption characteristics of reflective liquid crystal technology.
Solution Approach 2:
The patent makes the second TFT serve multiple functions: it controls both the liquid crystal element's orientation state and thereby regulates the light extraction efficiency from the light-emitting element. This multi-functional control mechanism enables the system to achieve both low power consumption (through reflective liquid crystal operation) and precise control capability (through independent TFT control of the liquid crystal state).
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 light extraction efficiency, enables light emission from the light-emitting element while controlling the liquid crystal layer, and reduces power consumption by utilizing a reflective liquid crystal element for low-power operation.
Implementation Method 1
a light-emitting element 120 having a convex-concave shape... the light-emitting layer 122 and the convex-concave layer 134 have a convex-concave shape... the light extraction efficiency of the light-emitting element 120 can be improved
Implementation Method 2
The second display element includes an electrode configured to reflect visible light
Data Source
AI summary
A light extraction efficiency is increased in a display device having a plurality of display elements. The display device includes a first display element and a second display element over the first display element, and the first display element has a convex-concave shape. The convex-concave shape overlaps with a first opening provided in a reflective electrode of the second display element. A user can see an image that combines the display from the first display element and the display from the second display element. The convex-concave shape increases the light extraction efficiency of the first display element. The second display element is electrically connected to a transistor through a second opening provided in any layer of the first display element. The second display element can be provided close to the first display element.