OLED Display Photo Sensor Condensing Lens for External Light
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Solution Overview
Problem
The efficiency of automatic luminance control in OLED displays is impaired due to the presence of a polarizing plate, which reduces the transmittance of external light to the photo sensor and can cause irregular reflections, leading to a decreased screen contrast ratio.
Innovation Solution
Incorporating a condensing lens with micro-lenses on the second substrate, either integral with the polarizing plate or spaced apart from it, to enhance the condensing efficiency of external light onto the photo sensor, thereby improving the sensitivity and maintaining a consistent screen contrast ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a polarizing plate is attached to the external face of the second substrate, then the screen contrast ratio is improved, but the transmittance of external light to the photo sensor is reduced
Solution Approach 1:
The external face of the second substrate is divided into two functional zones: a display area covered by the polarizing plate for high contrast ratio, and a sensor area left uncovered to allow external light transmission to the photo sensor. This spatial segmentation resolves the contradiction by allowing both functions to coexist without interference.
Solution Approach 2:
The polarizing plate is applied selectively only to the display area rather than the entire external face, creating local quality differentiation. The display area receives the polarizing treatment for optimal contrast, while the sensor area maintains optical transparency for light detection, thus resolving the trade-off between contrast enhancement and light transmission.
2Illumination intensity
If the polarizing plate covers the photo sensor area, then the screen contrast ratio is improved, but irregular reflection occurs and photo sensor efficiency decreases
Solution Approach 1:
The external face is segmented into display area and sensor area, with the polarizing plate applied only to the display area. This prevents the polarizing plate from covering the photo sensor, eliminating irregular reflections while maintaining high screen contrast ratio in the display area.
Solution Approach 2:
Different optical properties are applied to different areas: the display area has polarizing treatment for high contrast, while the sensor area remains non-polarized to ensure reliable light detection without irregular reflections, thus resolving the contradiction between contrast improvement and sensor reliability.
3Ease of manufacture
If the polarizing plate is spaced apart from the condensing lens, then manufacturing complexity is reduced, but light condensing efficiency may be affected
Solution Approach 1:
The condensing lens acts as an intermediary optical element between the external environment and the photo sensor. By positioning it between the polarizing plate and the photo sensor, it efficiently condenses external light onto the sensor while maintaining a simple manufacturing process where the polarizing plate and lens are separate components.
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 condensing lens increases the sensitivity of the photo sensor, allowing for more effective automatic brightness control and maintaining a consistent screen contrast ratio by efficiently condensing external light, even when a polarizing plate is used.
Implementation Method 1
a condensing lens arranged at an upper portion of the photo sensor to condense external light into the photo sensor
Implementation Method 2
a photo sensor that detects an amount of external light
Data Source
AI summary
An organic light emitting diode (OLED) display that includes a first substrate having a display area, a photo sensor arranged on a first substrate external to the display area, and a condensing lens arranged at an upper portion of the photo sensor to condense external light into the photo sensor, allowing the photo sensor to more efficiently detect an amount of external light. In this OLED display, an automatic luminance control function can be efficiently performed by increasing a condensing efficiency of the photo sensor.