Switchable Viewing Angle Backlight Module via Asymmetric Optical Structures
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Solution Overview
Problem
Portable electronic devices face challenges in privacy protection due to the inconvenience and cost of manually attaching and detaching anti-peeping films to adjust viewing angles, which are essential for public use while maintaining usability and convenience.
Innovation Solution
A display device with a backlight module featuring a light guide plate, first and second optical structures with different inclined surfaces, and a reflector, allowing for electronically switchable viewing angles by controlling the on/off states of the first and second light sources, eliminating the need for additional anti-peeping devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If anti-peeping films are manually attached to the display screen, then privacy protection is improved, but ease of operation deteriorates due to frequent manual attachment and detachment
Solution Approach 1:
The patent replaces the mechanical system of manual anti-peeping films with an optical system using light guide plates and optical structures. The viewing angle is controlled electronically through optical path design rather than manual film attachment, eliminating the need for frequent manual operations while maintaining privacy protection functionality.
Solution Approach 2:
The patent changes the parameter of light exit angle by designing optical structures with different inclination angles on the light guide plate. By controlling which optical structures are active, the system can switch between narrow viewing angles (for privacy) and wide viewing angles (for usability) without manual intervention.
2Object-affected harmful factors
If anti-peeping films are manually attached, then privacy protection is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent merges the anti-peeping function with the existing backlight module structure. The optical structures are integrated into the light guide plate, combining the privacy protection function with the illumination system, thereby reducing overall device complexity compared to adding separate anti-peeping films.
Solution Approach 2:
The light guide plate serves multiple functions: it guides light from the light source, controls the viewing angle through its optical structures, and provides the anti-peeping functionality. This multi-functionality eliminates the need for separate anti-peeping components, reducing device complexity.
3Object-affected harmful factors
If anti-peeping films are used, then privacy protection is improved, but loss of time increases due to frequent attachment and detachment
Solution Approach 1:
The patent replaces manual mechanical attachment of anti-peeping films with an electronic/optical control system. The viewing angle and privacy protection are adjusted electronically through control circuits and optical path design, eliminating the time-consuming manual attachment and detachment processes.
Solution Approach 2:
The optical structures are pre-configured on the light guide plate during manufacturing. The system is ready to provide different viewing angles and privacy levels immediately upon power-on or mode-switching, without requiring any preliminary manual preparation or attachment actions.
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 convenient and cost-effective electronic switching of viewing angles, providing both narrower and wider viewing options, enhancing privacy protection without the need for extra anti-peeping devices, while maintaining high brightness and usability.
Implementation Method 1
lights emitted from the first light source and the second light source respectively enter into the light guide plate from the first light incident surface and the second light incident surface, then are reflected by the first inclined surface or the second inclined surface
Implementation Method 2
refracted by the first inclined surface or the second inclined surface to the reflector and reflected by the reflector back to the light guide plate
Data Source
AI summary
A display device with switchable viewing includes a backlight module and a display panel. The backlight module includes a light guide plate, first optical structures, a reflector, a first light source, and a second light source. The light guide plate includes a bottom surface, a light exit surface, a first light incident surface, and a second light incident surface. The display panel is disposed on the light exit surface. The first optical structures are disposed on the bottom surface and each includes a first inclined surface and a second inclined surface. The angle between the first inclined surface and the bottom surface is smaller than that between the second inclined surface and the bottom surface. Lights from the first light source and the second light source enter the light guide plate from the first light incident surface and the second light incident surface, respectively. After entering the light guide plate, the lights can be reflected by the first inclined surface or the second inclined surface, or be refracted by the first inclined surface or the second inclined surface to the underlying reflector and reflected by the reflector back to the light guide plate from the first inclined surface or the second inclined surface. Based on such a structure, by controlling the on/off state of the first light source and the second light source, the viewing angle of the display device is switchable.