Under-Display Sensor Backlight Structure for Full-Screen Uniformity
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Solution Overview
Problem
The challenge of implementing a full-screen display in mobile terminals is hindered by the presence of front cameras, which limit screen size and require design compromises such as notches or punch holes, and existing solutions for integrating cameras in displays often result in visible imaging areas and dark areas due to sensor interference.
Innovation Solution
A display device design featuring a backlight unit with a light guide plate, a reflector, and a sensor under a second display area, where the reflector reflects visible light to maintain camera performance and hide the imaging area, while using optical sheets and prisms to enhance light uniformity and minimize dark areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a camera and sensors are disposed in the imaging area to implement full-screen display, then the screen size is increased, but the imaging area becomes visible from the outside
Solution Approach 1:
A reflector is introduced as an intermediary component between the imaging area and the external environment. The reflector reflects incident visible light toward the display panel, preventing direct viewing of the imaging area while maintaining camera functionality. This mediator effectively hides the imaging area from external observation.
Solution Approach 2:
The reflector utilizes optical properties to manipulate light interaction. By reflecting visible light in specific directions, the imaging area appears consistent with the surrounding display area, making it invisible from the outside while allowing sensor operations.
2Object-affected harmful factors
If a reflector is disposed between the second display area and the sensor to hide the imaging area, then the imaging area is not visible, but dark areas are generated due to light blocking
Solution Approach 1:
The light guide plate is designed with spatially varying properties. The first light guide plate has a first refractive index optimized for light transmission, while the second light guide plate has a second refractive index optimized for light reflection. This local differentiation allows the reflector to hide the imaging area while the light guide plates compensate for light distribution, preventing dark areas.
Solution Approach 2:
Light guide plates are introduced as intermediary components between the light source and the display panel. These plates manage light propagation and distribution, compensating for the light blocking effect of the reflector and maintaining uniform illumination across the display area.
3Reliability
If the light guide plate thickness is increased to improve light reflection, then the camera performance is enhanced, but the device size increases
Solution Approach 1:
The light guide plate structure uses local thickness variation optimized for specific functions. The first light guide plate has a thickness optimized for light transmission to the display panel, while the second light guide plate has a thickness optimized for light reflection toward the imaging area. This localized optimization achieves camera performance enhancement without requiring uniform thickness increase throughout the entire light guide plate structure.
Solution Approach 2:
The patent utilizes the thickness dimension of the light guide plate to control optical properties. By varying thickness in the vertical dimension, the design achieves improved light reflection and camera performance without increasing the horizontal footprint of the device.
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 solution achieves a full-screen display by hiding the imaging area and improving light uniformity, allowing for a more compact and efficient design with reduced dark areas and enhanced sensor performance.
Implementation Method 1
a reflector disposed between the second display area and the sensor and reflecting incident visible light to the second display area
Implementation Method 2
a light guide plate disposed under the first display area and the second display area, a light source configured to radiate light to the light guide plate
Data Source
Figure 1~2A
Figure 2B~3
Figure 4(a)~4(b)
AI summary
An embodiment discloses a display device (10) including a backlight unit (300), a display panel (100) disposed on the backlight unit (300) and including a first display area (DA1) and a second display area (DA2), and a sensor (CM) disposed under the second display area (DA2), wherein the backlight unit (300) includes a light guide plate (320) disposed under the first display area (DA1) and the second display area (DA2), a light source (310) configured to radiate light to the light guide plate (320), and a reflector (340) disposed between the second display area (DA2) and the sensor (CM) and reflecting incident visible light to the second display area (DA2).