Transparent-Electrode Photodiode Layout for In-Screen Light Absorption
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Solution Overview
Problem
Current photodiodes used in in-screen fingerprint recognition have a low light absorption rate due to the p-doped and n-doped layers, which reduces photoelectric conversion efficiency.
Innovation Solution
A photodiode structure comprising a first electrode made of transparent conductive material at the bottom and a metal electrode at the top, or vice versa, depending on the incident light direction, with an electron transport layer, a light conversion layer, and a hole transport layer to enhance light absorption and photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If p-doped layer and n-doped layer are used in photodiode structure, then photoelectric conversion function is achieved, but light absorption rate decreases
Solution Approach 1:
The patent removes the p-doped layer and n-doped layer from the photodiode structure, extracting the harmful light-absorbing components while retaining the essential photoelectric conversion function through alternative electron transport and hole transport layers
Solution Approach 2:
The patent employs composite material structure with electron transport layer and hole transport layer made of transparent materials that have both good charge transport performance and high light transmittance, resolving the contradiction between functional reliability and light absorption
2Reliability
If light conversion layer thickness is increased to improve light absorption, then photoelectric conversion efficiency improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent optimizes the thickness parameters of the light conversion layer and transport layers to achieve optimal photoelectric conversion efficiency without excessive thickness, balancing performance with manufacturing feasibility
Solution Approach 2:
By using transparent electron transport and hole transport layers with high light transmittance, the patent reduces the required thickness of the light conversion layer, thereby improving photoelectric conversion efficiency while keeping the overall structure simple and manufacturable
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 described photodiode structure increases light absorption and photoelectric conversion efficiency by optimizing the placement of transparent conductive and metal electrodes, allowing more light to be received by the light conversion layer, thereby improving fingerprint recognition accuracy.
Implementation Method 1
a light conversion layer disposed on the electron transport layer... improving a light absorption rate and photoelectric conversion efficiency
Data Source
AI summary
The present invention provides a photodiode and a display screen. The photodiode includes a first electrode and a second electrode in order. When a direction of an incident light of the photodiode is a first direction, a material of the first electrode is a transparent conductive material, and a material of the second electrode is a metal material. When the direction of the incident light of the photodiode is a second direction, the second electrode is made of a transparent conductive material, and the first electrode is made of a metal material.