Shared Amplifier Circuit for LCD Pixel Photosensors
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Solution Overview
Problem
Incorporating a photosensor circuit into a display portion with a limited number of masks leads to increased dead space due to the area difference between the amplifier circuit and light-receiving portions, reducing the aperture ratio and increasing manufacturing costs, especially when using photodiodes with stacked semiconductor layers.
Innovation Solution
A semiconductor device with a shared amplifier circuit among multiple pixels, utilizing a non-single-crystal semiconductor layer for the light-receiving elements, which reduces the area of the photosensor circuit and increases the aperture ratio, while maintaining high photosensitivity without the need for additional layers, thus minimizing manufacturing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the area of the light-receiving portion is increased to increase photosensitivity, then the photosensitivity is improved, but the area of the photosensor circuit in the display portion increases, leading to more dead space
Solution Approach 1:
The amplifier circuit portion is merged with the light-receiving portion by forming both on the same plane using the same mask, eliminating the need for additional masks and reducing the overall area of the photosensor circuit while maintaining high photosensitivity through an enlarged light-receiving portion
Solution Approach 2:
The same mask is used to form both the amplifier circuit portion and the light-receiving portion, making the mask serve multiple functions and simplifying the manufacturing process while reducing dead space in the display portion
2Measurement precision
If a photodiode with stacked semiconductor layers is used for the light-receiving element, then the photosensitivity is improved, but the number of manufacturing steps increases, leading to higher manufacturing costs
Solution Approach 1:
The complex stacked structure of multiple semiconductor layers (p-layer, i-layer, n-layer) is extracted and replaced with a simplified single-layer amorphous silicon structure that achieves the same photodetection function with fewer manufacturing steps
Solution Approach 2:
The material parameter is changed from a stacked multi-layer semiconductor structure to a single-layer amorphous silicon structure, maintaining the essential photodetection functionality while reducing manufacturing complexity and cost
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 dead space, increases the aperture ratio, and decreases power consumption by sharing the amplifier circuit among pixels, while maintaining high photosensitivity using a simplified process with non-single-crystal semiconductor layers, thereby addressing the challenges of area differences and manufacturing costs.
Implementation Method 1
a light-receiving element and an amplifier circuit portion, wherein one amplifier circuit portion is shared by a plurality of light-receiving elements
Data Source
AI summary
In a display portion of a liquid crystal display device, the dead space corresponding to a unit pixel is reduced while the aperture ratio of the unit pixel is increased. One amplifier circuit portion is shared by a plurality of unit pixels, so that the area of the amplifier circuit portion corresponding to the unit pixel is reduced and the aperture ratio of the unit pixel is increased. In addition, when the amplifier circuit portion is shared by a larger number of unit pixels, a photosensor circuit corresponding to the unit pixel can be prevented from increasing in area even with an increase in photosensitivity. Furthermore, an increase in the aperture ratio of the unit pixel results in a reduction in the power consumption of a backlight in a liquid crystal display device.