Display device and method for manufacturing the same
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In display devices, the increased pixel density leads to reduced writing time for display images, necessitating high-speed operation of transistors in the driver circuit portion, while also causing a decrease in aperture ratio in the pixel portion, which affects switching characteristics.
Innovation Solution
A display device is designed with a pixel portion and a driver circuit portion on one substrate, where the pixel portion includes a first transistor with a light-transmitting structure and the driver circuit portion includes a second transistor with a similar structure, optimized for high-speed operation and high aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel density is increased, then display resolution is improved, but aperture ratio decreases
Solution Approach 1:
The patent applies different transistor structures to different functional regions: the pixel portion uses a bottom-gate transistor structure with light-transmitting electrodes to maximize aperture ratio, while the driver circuit portion uses an inverted-gate transistor structure optimized for high-speed operation. This local differentiation allows each region to achieve its optimal performance characteristics.
Solution Approach 2:
The display device is segmented into distinct functional regions with specialized transistor designs. The pixel portion and driver circuit portion are separated and each employs transistors optimized for its specific function, allowing simultaneous achievement of high aperture ratio in pixels and high operation speed in driver circuits.
2Measurement precision
If pixel density is increased, then display resolution is improved, but writing time is reduced
Solution Approach 1:
The driver circuit transistors are specifically designed with inverted-gate structure and optimized dimensions to achieve high operation speed, compensating for the reduced writing time caused by increased pixel density. This localized optimization ensures sufficient writing time even at high resolutions.
3Loss of time
If transistor operation speed is increased for driver circuit, then writing time is sufficient, but device complexity increases
Solution Approach 1:
The patent optimizes transistor parameters such as channel width and length, gate electrode thickness, and layer compositions to achieve high operation speed. By carefully controlling these parameters within practical ranges, high performance is achieved without excessive complexity.
Solution Approach 2:
The transistor structures employ composite material systems including oxide semiconductor layers, metal oxide gate electrodes, and multi-layer insulating films. These composite structures enable high-speed operation while maintaining manufacturability and controlling device complexity.
Data Source
AI summary
An object is to provide a display device with excellent display characteristics, where a pixel circuit and a driver circuit provided over one substrate are formed using transistors which have different structures corresponding to characteristics of the respective circuits. The driver circuit portion includes a driver circuit transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using a metal film, and a channel layer is formed using an oxide semiconductor. The pixel portion includes a pixel transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using an oxide conductor, and a semiconductor layer is formed using an oxide semiconductor. The pixel transistor is formed using a light-transmitting material, and thus, a display device with higher aperture ratio can be manufactured.