Organic EL Device Light Shield Layer for Sensor Accuracy
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Solution Overview
Problem
Existing organic electroluminescence (EL) devices face challenges in effectively integrating a light sensor with the organic EL element, as the emitted light from the EL element can interfere with the light sensor's detection capability, leading to reduced accuracy in ambient light detection.
Innovation Solution
The integration of a light-shield layer between the light sensor and the sealing substrate, with an opening portion above the light-sensing part, reduces the influence of emitted light from the organic EL element, enhancing the light sensor's detection capability while sharing manufacturing processes with the pixel circuit components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light sensor is integrated with the organic EL element, then the device can detect ambient light and serve as a contact input device, but the emitted light from the EL element interferes with the light sensor's detection capability
Solution Approach 1:
The pixel structure is segmented into distinct functional regions: a light-emission part containing the organic EL element and a separate light-receiving part containing the light sensor. This spatial segmentation allows both functions to coexist while minimizing interference, as the light sensor is positioned to receive ambient light through a dedicated opening while the EL element emits light in a different direction.
Solution Approach 2:
Different regions of the pixel are assigned different optical properties. The light-receiving part has high light transmissivity to allow ambient light to reach the sensor, while the light-emission part has controlled light emission characteristics. The light-shield layer is selectively positioned to block EL light from reaching the sensor while allowing ambient light to pass through to the sensor.
2Ease of operation
If the light sensor is positioned to receive light through the sealing substrate, then ambient light detection is enabled, but emitted light from the EL element and reflective light interfere with detection accuracy
Solution Approach 1:
A light-shield layer is introduced as an intermediary component between the EL element and the light sensor. This layer selectively blocks harmful light (EL emitted light and reflective light) from reaching the sensor while allowing ambient light to pass through. The light-shield layer is positioned in the light-receiving part and has a light-transmissive opening that aligns with the sensor, creating a controlled optical path.
3Measurement precision
If additional light-shielding structures are added to reduce interference, then detection accuracy improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The light-shield layer is merged with existing pixel circuit components rather than being implemented as a separate additional structure. Specifically, the light-shield layer is formed in the same opening where the light sensor is positioned, and the same opening also serves as the light-receiving opening. This merging approach achieves light shielding functionality without adding separate complex structures.
Solution Approach 2:
The opening in the pixel structure serves multiple functions simultaneously: it allows ambient light to reach the light sensor, provides the light-receiving aperture for the sensor, and when filled with the light-shield layer, blocks harmful light from the EL element. This multi-functionality reduces the need for additional dedicated structures for each function.
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
This configuration improves the light sensor's detection accuracy by minimizing the impact of emitted light and reflective light, allowing for effective ambient light detection and potential use as a contact input device, while maintaining cost-effectiveness in manufacturing.
Implementation Method 1
a light sensor which is provided in the array substrate and includes a light-sensing part which receives incident light via the sealing substrate
Implementation Method 2
a light-shield layer which is disposed between the light sensor and the sealing substrate, and includes an opening portion which is formed right above the light-sensing part of the light sensor
Data Source
AI summary
An organic EL device includes an array substrate including an insulating substrate and an organic EL element which is disposed above the insulating substrate, a sealing substrate which is disposed on that side of the array substrate, which faces the organic EL element, and is attached to the array substrate, a light sensor which is provided in the array substrate and includes a light-sensing part which receives incident light via the sealing substrate, and a light-shield layer which is disposed between the light sensor and the sealing substrate, and includes an opening portion which is formed right above the light-sensing part of the light sensor.