Photosensor Light-Shielding Structure for OLED Illuminance Detection
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Solution Overview
Problem
Organic electroluminescence display devices face challenges in accurately detecting external light illuminance due to light emitted from the electroluminescence layer interfering with optical sensors, causing incorrect measurements and sensitivity saturation.
Innovation Solution
A photosensor design featuring a first and second light-shielding layer, insulating layers, and a semiconductor diode structure that shields lateral light and allows accurate detection of external light illuminance by preventing internal light from entering the semiconductor layer, improving sensitivity and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical sensor is arranged on the same substrate as the light-emitting layer, then the display device can detect external light illuminance, but light emitted from the light-emitting layer interferes with the optical sensor causing incorrect measurements and sensitivity saturation
Solution Approach 1:
The device is segmented into distinct functional regions: a display region with light-emitting elements and a sensor region with the optical sensor. This spatial segmentation prevents light from the display region from interfering with the sensor, allowing accurate external light illuminance detection while maintaining display functionality.
Solution Approach 2:
The optical sensor is extracted from the display region and placed in a separate sensor region. This extraction removes the sensor from the harmful light environment of the display region, enabling it to accurately detect external light without being saturated by internal light emission.
2Measurement precision
If the optical sensor is placed in the peripheral region, then internal light interference is reduced, but the device complexity increases due to additional light-shielding layers and structural modifications
Solution Approach 1:
The light-shielding layer is merged with the lower electrode layer of the light-emitting element, forming a multi-functional layer that serves both as an electrode for light emission control and as a shield against light interference. This merging reduces the total number of separate layers and simplifies the overall device structure.
Solution Approach 2:
The lower electrode layer is given dual functionality: it serves as an electrical electrode for the light-emitting element and simultaneously as a light-shielding layer to protect the optical sensor. This multi-functionality reduces device complexity by eliminating the need for separate dedicated light-shielding structures.
3Measurement precision
If a light-shielding layer is added to block internal light, then detection accuracy improves, but the manufacturing process becomes more complex
Solution Approach 1:
The light-shielding function is combined with the lower electrode layer formation process. By using the same layer for both electrical and optical functions, the manufacturing process does not require additional dedicated light-shielding deposition steps, maintaining ease of manufacture while achieving improved detection accuracy.
Solution Approach 2:
The lower electrode layer performs multiple functions including electrical conduction and light shielding. This multi-functionality reduces the total number of manufacturing steps by eliminating the need for separate light-shielding layer deposition, thus maintaining manufacturing simplicity while improving measurement accuracy.
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 photosensor effectively enhances the detection accuracy of external light illuminance, reducing interference from internal light sources and improving sensitivity, thereby correcting illuminance measurements in organic electroluminescence display devices.
Implementation Method 1
a semiconductor layer provided on the first insulating layer, the semiconductor layer being connected to a first electrode and a second electrode, and the semiconductor layer configuring a diode
Data Source
AI summary
A photosensor includes a first light-shielding layer provided on an insulating surface; a first insulating layer covering the first light-shielding layer; a semiconductor layer provided on the first insulating layer, the semiconductor layer being connected to a first electrode and a second electrode, and the semiconductor layer configuring a diode; a second insulating layer covering the semiconductor layer; an opening provided in the second insulating layer so as to surround the semiconductor layer as viewed from a planar direction and the opening reaching at least the first insulating layer; and a second light-shielding layer covering at least a side wall of the opening.