Tapered Common Electrode Stray Light Inhibition
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Solution Overview
Problem
Existing display apparatuses face challenges in achieving high detection sensitivity for image capturing functions, maintaining high display quality, and attaining high resolution due to issues with stray light inhibition, voltage drop, and resistance in common electrodes, particularly in top-emission structures and organic EL element manufacturing methods.
Innovation Solution
The display apparatus incorporates a first and second light-emitting device with tapered lower electrodes and organic compound layers, a common electrode, an insulating layer, and auxiliary wiring electrically connected to the common electrode, which is positioned to overlap with the insulating layer and has a shape that inhibits voltage drop and stray light, enhancing detection sensitivity and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light-blocking layer is provided on a counter substrate to inhibit stray light, then stray light inhibition is improved, but the detection sensitivity of the image capturing function cannot be sufficiently enhanced
Solution Approach 1:
The patent moves the light-blocking function from a separate counter substrate layer to the common electrode itself by forming a tapered shape at the end portion. This dimensional repositioning allows the common electrode to simultaneously serve as both an electrical conductor and a stray light blocking structure, improving detection sensitivity without requiring additional light-blocking layers that would interfere with image capture
Solution Approach 2:
The common electrode is designed to perform multiple functions: it serves as an electrical common reference for the light-emitting devices and simultaneously functions as a light-blocking structure through its tapered end portion. This multi-functionality eliminates the need for separate dedicated light-blocking components that would compromise image capturing performance
2Illumination intensity
If a conductive material having light-transmitting property is used for the common electrode to enable top-emission structure, then light extraction is improved, but the resistance becomes high causing voltage drop
Solution Approach 1:
The common electrode is designed with different properties in different regions: the main body uses a light-transmitting conductive material for efficient light extraction, while the end portion is formed with a tapered shape that blocks stray light. This local differentiation allows each region to optimize its function without compromising the other
Solution Approach 2:
The patent changes the geometric parameters of the common electrode by forming a tapered shape at the end portion. This parameter change allows the electrode to maintain light-transmitting properties in the main area while creating a light-blocking profile at the edges, resolving the contradiction between light extraction and stray light inhibition
3Ease of manufacture
If standard UV photolithography is used for manufacturing organic EL elements, then manufacturing process is simplified, but high resolution cannot be achieved
Solution Approach 1:
The manufacturing process is segmented into multiple stages: first forming the organic EL elements using standard UV photolithography for ease of manufacture, then subsequently forming the tapered common electrode structure to achieve high resolution. This segmentation allows each process stage to be optimized independently, combining simple manufacturing with high precision
Data Source
AI summary
A display apparatus with high detection sensitivity of an image capturing function and high display quality is provided. The display apparatus includes a light-receiving device; a first light-emitting device including a first lower electrode whose end portion has a first tapered shape and a first organic compound layer having a shape along the first tapered shape; a second light-emitting device including a second lower electrode whose end portion has a second tapered shape and a second organic compound layer having a shape along the second tapered shape; a common electrode included in the first light-emitting device and the second light-emitting device; an insulating layer positioned between the first light-emitting device and the second light-emitting device and between the second light-emitting device and the light-receiving device; and an auxiliary wiring electrically connected to the common electrode. The auxiliary wiring is positioned over the common electrode and includes a region overlapping with the insulating layer.