Foreign Substance Inspection for OLED Units via Reflected Light
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Solution Overview
Problem
Existing foreign substance inspection systems for display units, particularly organic light emitting display units, face challenges in detecting foreign substances due to the opaque substrate configuration, making it difficult to use light transmission optical systems effectively.
Innovation Solution
A foreign substance inspection system that employs a lighting unit providing incident light at an inclined angle and a foreign substance detecting unit with a quarter-wave plate and polarizing plate configuration, which captures and analyzes reflected light to determine the presence of foreign substances without relying on light transmission optical systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a light transmission optical system is used to inspect foreign substances, then inspection effectiveness is improved for liquid crystal display units, but the system cannot be applied to organic light emitting display units due to opaque substrates
Solution Approach 1:
The patent inverts the inspection approach from light transmission to light reflection. Instead of shining light through the display unit from one side and detecting transmitted light, the system shines light from one side and detects reflected light from the same side. This inversion allows the inspection system to work with opaque substrates in OLED units while maintaining foreign substance detection capability.
Solution Approach 2:
The patent changes the optical detection parameter from transmission to reflection. By using a reflection optical system instead of a transmission optical system, the inspection method adapts to the opaque substrate characteristics of OLED units. The system uses polarizing plates and quarter-wave plates to manipulate reflected light properties for effective foreign substance detection.
2Ease of manufacture
If an opaque substrate is used in organic light emitting display units, then device functionality is achieved, but light transmission for foreign substance inspection becomes impossible
Solution Approach 1:
The patent introduces polarizing plates and quarter-wave plates as intermediary optical elements between the light source and the opaque substrate. These intermediaries manipulate the polarization state of incident and reflected light, enabling the detection system to extract foreign substance information from reflected light even when the substrate is opaque. The polarizing elements act as mediators that make the invisible visible by creating detectable optical contrast.
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
Enables effective inspection of foreign substances in organic light emitting display units by distinguishing reflected light patterns, allowing for accurate detection without the need for light transmission systems, thereby categorizing defective products correctly.
Implementation Method 1
when light is incident on one surface of the liquid crystal display unit, the light may travel toward the other surface of the liquid crystal display unit and be transmitted. At this time, the light scatters if a foreign substance is introduced between the film and the liquid crystal panel.
Implementation Method 2
a foreign substance detecting unit configured to receive incident light that is reflected by the display unit
Implementation Method 3
the display unit may include a quarter-wave plate (QWP) disposed on the organic light emitting display panel, and a polarizing plate disposed on the quarter-wave plate
Data Source
AI summary
An exemplary embodiment of the present invention provides a foreign substance inspection system for a display unit, including: a lighting unit configured to provide incident light to a display unit having an organic light emitting display panel; and a foreign substance detecting unit configured to receive incident light that is reflected by the display unit and detect whether a foreign substance is introduced into the display unit.