Dual-Unit Backlight Module for Side-View Sharing and Privacy
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Solution Overview
Problem
Existing display devices struggle with switching between wide and narrow viewing angles efficiently, leading to issues such as reduced brightness or high manufacturing costs, and there is a need for biased viewing angles to prevent driver distraction in vehicles.
Innovation Solution
A backlight module capable of switching between side and narrow viewing modes, utilizing an upper and lower backlight unit with specific light guide plate designs and light control films to control light direction, allowing for efficient luminance distribution and privacy protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a privacy filter is added on the outermost layer to achieve narrow viewing angle, then viewing angle is reduced, but brightness is noticeably reduced
Solution Approach 1:
The backlight module is divided into multiple independent light emitting regions (first light emitting region and second light emitting region) that can be independently controlled. This segmentation allows different viewing angle characteristics to be achieved in different regions without compromising overall brightness, as each region can be optimized for its specific function.
Solution Approach 2:
Different regions of the backlight module are designed with different optical properties. The first light emitting region uses a first optical film to achieve narrow viewing angle (privacy mode), while the second light emitting region uses a second optical film to maintain wide viewing angle. This local differentiation allows brightness to be maintained in the wide viewing angle region while achieving privacy protection in the narrow viewing angle region.
2Adaptability or versatility
If an active dedicated display panel is used for each viewing angle mode to achieve viewing angle switching, then viewing angle control is improved, but manufacturing cost increases
Solution Approach 1:
A single backlight module is designed to perform multiple functions by incorporating both a first optical film and a second optical film. The first optical film enables narrow viewing angle mode, while the second optical film enables wide viewing angle mode. By using one multi-functional backlight module instead of multiple dedicated modules, manufacturing complexity and cost are reduced while maintaining the ability to switch between different viewing angle modes.
3Object-affected harmful factors
If display is positioned in front of passenger seat with narrow viewing angle to prevent driver distraction, then driver safety is improved, but ability to share information with driver is reduced
Solution Approach 1:
The backlight module dynamically switches between different viewing angle modes based on operational requirements. When privacy protection is needed, the narrow viewing angle mode is activated to prevent driver distraction. When information sharing is needed, the wide viewing angle mode is activated to allow the driver to view the display. This dynamic switching capability resolves the contradiction between preventing distraction and enabling information sharing.
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 simultaneous viewing by the driver and passenger in the side viewing mode with sufficient brightness, and privacy protection in the narrow viewing mode, enhancing driving safety and reducing energy consumption.
Implementation Method 1
an optical film having a first surface and a second surface opposite to each other, and a light incident microstructure formed on the first surface
Implementation Method 2
a light incident microstructure formed on the first surface
Data Source
AI summary
A backlight module has a first side viewing angle luminance LAS1 and a first normal viewing angle luminance LAN1 in the side viewing mode, wherein LAS1/LAN1>50%. The backlight module has a second side viewing angle luminance LAS2 and a second normal viewing angle luminance LAN2 in the narrow viewing mode, wherein LAS2/LAN2<0.5%. The first side angle and the second side angle occur in a slanting direction. The first normal view and the second normal view occur in a normal direction. When executing a side viewing execution step, an upper backlight unit and a lower backlight unit are activated to form the side viewing mode. When executing a narrow viewing execution step, the upper backlight unit is turned off and the lower backlight unit is activated to form the narrow viewing mode. The invention also provides a display device including the backlight module.