Switchable Backlight Module for Wide and Narrow Viewing Angles
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Solution Overview
Problem
Existing display devices struggle to efficiently switch between wide and narrow viewing angles without compromising brightness or incurring high manufacturing costs, particularly in vehicle displays where privacy and sharing modes are required.
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 structures and light control films to control light distribution, allowing for adjustable viewing angles and luminance ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a privacy filter is added on the outermost layer to achieve narrow viewing angle, then privacy mode is enabled, but brightness is noticeably reduced
Solution Approach 1:
The patent implements dynamic switching between different backlight units (first backlight unit for narrow viewing angle, second backlight unit for wide viewing angle) based on operational mode requirements. This allows the system to adaptively change its optical characteristics without compromising brightness in either mode, resolving the contradiction between privacy protection and brightness maintenance.
2Adaptability or versatility
If an active dedicated display panel is used for each viewing angle mode to control different viewing angles, then viewing angle switching is achieved, but manufacturing cost increases
Solution Approach 1:
The patent segments the backlight system into multiple independent backlight units, each optimized for specific viewing angle modes. Instead of requiring multiple complete display panels, only the backlight portion is segmented and switched, significantly reducing manufacturing complexity and cost while maintaining the capability to switch between narrow and wide viewing angles.
Solution Approach 2:
The patent creates a universal display system that can operate in multiple viewing angle modes using a single display panel combined with switchable backlight units. This multi-functional approach eliminates the need for separate dedicated display panels for each mode, reducing manufacturing costs while maintaining adaptability.
3Reliability
If the display is positioned in front of the passenger seat with narrow viewing angle to prevent driver distraction, then driving safety is improved, but the ability to share information with the driver is reduced
Solution Approach 1:
The patent implements dynamic switching between narrow viewing angle mode (for driving safety when the display is in front of the passenger seat) and wide viewing angle mode (for information sharing with the driver). The system can adaptively change the viewing angle characteristic based on the operational context, maintaining both driving safety and information sharing capability at different times.
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 multiple passengers and privacy for the driver by maintaining sufficient brightness in side viewing mode and reducing interference in narrow viewing mode, enhancing driving safety and reducing energy consumption.
Implementation Method 1
the light field of the light source is expanded to achieve the purpose of emitting light at a specific angle
Implementation Method 2
the light field of the light source is expanded to achieve the purpose of emitting light at a specific angle
Data Source
AI summary
A backlight module comprises an upper and a lower backlight unit. The upper unit includes an upper light source and a substantially rectangular upper light guide plate with a first side edge along a first axis and a second side edge along a second axis which is non-parallel to the first axis. The upper light source is positioned adjacent to the second side edge and extends along the second axis, directing light primarily along the first axis within the light guide plate. 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.