Light Shielding Pattern for IR Sensor Transistor Stability
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Solution Overview
Problem
The operation of an IR sensor in display devices can cause changes in the characteristics of transistors due to IR light emission, leading to abnormal off currents and gradation issues in organic light emitting display devices.
Innovation Solution
Incorporating a light shielding pattern around the transistors, including a lower light shielding layer and side light shielding patterns that extend through the insulating layers, to prevent IR light from entering the semiconductor layer and mitigate these changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an IR sensor is located in the display area to achieve bezel-less display, then the bezel size is reduced, but the transistor characteristics change due to IR light emission
Solution Approach 1:
A light shielding pattern is introduced as an intermediary element between the IR sensor and the transistor. This pattern includes a lower light shielding layer and side light shielding patterns that extend through insulating layers, effectively blocking IR light from reaching the semiconductor layer while allowing the IR sensor to remain in the display area for bezel-less operation
2Adaptability or versatility
If the IR sensor is operated for call mode functionality, then the call function is enabled, but abnormal off currents occur in transistors
Solution Approach 1:
The light shielding pattern serves as a protective intermediary that allows the IR sensor to operate for call mode functionality while preventing harmful IR light from reaching the transistor, thereby eliminating abnormal off currents and maintaining reliable transistor operation during sensor activation
3Device complexity
If no light shielding structure is added to maintain simple device structure, then manufacturing complexity is low, but gradation issues occur due to IR light affecting transistors
Solution Approach 1:
A light shielding pattern is introduced as an intermediary element between the IR sensor and the transistor. This pattern includes a lower light shielding layer and side light shielding patterns that extend through insulating layers, effectively blocking IR light from reaching the semiconductor layer while allowing the IR sensor to remain in the display area for bezel-less operation
Solution Approach 2:
The light shielding pattern is strategically positioned only around the transistor regions that are susceptible to IR light effects, rather than covering the entire display area. This localized approach protects critical areas while maintaining overall device performance and minimizing impact on display quality
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 light shielding pattern effectively prevents IR light from affecting the transistors, reducing abnormal off currents and maintaining consistent gradation in the display device.
Implementation Method 1
the characteristics of the transistors of the display device may change due to IR light emitted when the IR sensor is operated
Data Source
AI summary
A display device includes: a substrate; an active layer; a first insulating layer on the active layer; a gate electrode; a second insulating layer on the first conductive layer; a second conductive layer on the second insulating layer; a third insulating layer on the second conductive layer; and a source electrode connected to the source region of the first active pattern through a contact hole passing through the first insulating layer and the second insulating layer, and a drain electrode connected to the drain region, wherein the first active pattern, the gate electrode, the source electrode and the drain electrode constitute a thin film transistor, the display device further comprising at least one light shielding pattern around the thin film transistor, wherein the light shielding pattern includes a side light shielding pattern such that the third conductive layer passes through at least the third insulating layer.