Rear-Side Photosensor and Reflection Layer for OLED Luminance Correction
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Solution Overview
Problem
In OLED display devices, pixel degradation can lead to reduced light output, and existing correction methods fail when light is not transmitted to photosensors, preventing effective correction of deteriorated pixels.
Innovation Solution
A display device with a reflection layer facing the OLED to amplify light output and a photosensor on the rear side to measure luminance, positioned below the encapsulation glass and black matrix, which generates control signals to correct light output based on measured luminance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photosensor is positioned on the front side to measure light output, then light measurement is straightforward, but light from the OLED blocks the photosensor and prevents accurate measurement of degraded pixels
Solution Approach 1:
The patent positions the photosensor on the rear side of the OLED and uses a reflection layer to reflect light back to the photosensor, inverting the conventional front-side measurement approach. This allows the photosensor to measure light output without being blocked by the OLED structure, solving the light blocking problem while maintaining measurement accuracy
Solution Approach 2:
The patent changes the measurement dimension from front-side direct measurement to rear-side reflected measurement. By positioning the photosensor on the rear side and using the reflection layer to redirect light, the system measures light output through a different spatial dimension, avoiding the blocking issue while achieving accurate degradation detection
2Measurement precision
If light output to the rear side is weak, then the photosensor cannot accurately measure luminance, but adding a reflection layer increases device complexity
Solution Approach 1:
The reflection layer acts as an intermediary between the OLED and the photosensor, capturing light emitted to the rear side and redirecting it to the photosensor. This intermediary component amplifies the weak light signal without requiring complex optical systems, achieving accurate luminance measurement while maintaining relatively simple device structure
Solution Approach 2:
The reflection layer utilizes the existing light emission from the OLED and redirects it back to the photosensor, making the system self-sufficient. The OLED's own light output is reused through the reflection layer, eliminating the need for external light sources or complex measurement systems
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
Efficiently corrects OLED pixel degradation by amplifying light output and determining necessary corrections, ensuring effective light emission and extending the lifespan of OLEDs.
Implementation Method 1
a reflection layer formed to face the OLED and to reflect light of the OLED
Implementation Method 2
a photosensor for measuring luminance of the reflected light
Data Source
AI summary
A pixel and a display device including the same are disclosed. In one aspect, the pixel includes an organic light-emitting diode (OLED) and a reflection layer facing the OLED and configured to reflect light emitted from the OLED. The pixel also includes a photosensor configured to measure luminance of the reflected light. The photosensor is placed on a rear side of the OLED.