Prismatic Backlight Film Structure for Switchable Privacy Viewing
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Solution Overview
Problem
Display devices in mobile devices have wide viewing angles, leading to the leakage of business secrets and personal privacy in public places due to others being able to clearly see the display images.
Innovation Solution
A backlight module with a prismatic reflective film featuring uneven protruding structures on its surface, which reduces contact area with the light guide plate and includes a dimming structure to adjust light angles, combined with a dimming and backlight driver chip to switch between sharing and anti-peeping states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a prismatic reflective film with protruding structures is used to reduce contact area with the light guide plate, then the risk of surface damage to the light guide plate is reduced, but the manufacturing precision of the reflective film structure becomes more complex
Solution Approach 1:
The protruding structures on the reflective film are designed with curved surfaces instead of sharp edges, where the curvature radius is specifically controlled to be between 1-10 micrometers. This curved geometry reduces stress concentration and minimizes the risk of scratching the light guide plate surface while maintaining effective light reflection functionality.
Solution Approach 2:
The reflective film employs local quality variation by creating protruding structures with specific geometric characteristics (curvature radius, height, and distribution density) in different regions. This allows the film to provide both mechanical protection (through reduced contact area) and optical functionality (through controlled light reflection) in different locations.
2Object-affected harmful factors
If the tops of protruding structures are made uneven to further reduce contact area, then privacy protection effectiveness is improved, but the device complexity increases
Solution Approach 1:
The tops of the protruding structures are designed with asymmetric and uneven heights, creating a more complex three-dimensional surface profile. This asymmetry further reduces the contact area with the light guide plate while enhancing the privacy protection effect by creating more varied light reflection paths that are harder to predict and control for unauthorized viewing.
Solution Approach 2:
The design transitions from two-dimensional flat or uniformly textured surfaces to three-dimensional uneven protruding structures with varying heights and curvatures. This dimensional complexity adds another layer of light interaction control, creating multiple reflection paths and angles that enhance privacy protection while managing the increased structural complexity through controlled geometric parameters.
3Object-affected harmful factors
If a dimming structure is added to adjust light angles for privacy protection, then privacy protection capability is improved, but the device complexity and number of components increases
Solution Approach 1:
The dimming structure is integrated with the existing backlight module architecture, combining multiple functions (light reflection, angle control, and privacy protection) into a unified system. The dimming structure works in conjunction with the prismatic reflective film and light guide plate rather than operating as a completely separate component, thereby reducing overall system complexity.
Solution Approach 2:
The dimming structure serves multiple functions: it controls light emission angles for privacy protection, adjusts viewing angles for different usage scenarios, and works synergistically with the prismatic reflective film to enhance overall light management efficiency. This multi-functionality justifies the added component by providing several benefits from a single addition.
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 effectively reduces the risk of privacy leakage by minimizing surface damage to the light guide plate and allowing controlled light emission angles, enhancing privacy in public use scenarios.
Implementation Method 1
The prismatic reflective film serves as a reflective sheet to reflect the light emitted from a surface of the light guide plate opposite to the light exit surface of the light guide plate, i.e., the back side, into the light guide plate
Data Source
AI summary
A backlight module includes a light guide plate and a prismatic reflective film. The prismatic reflective film is disposed on a surface of the light guide plate opposite to a light exit surface of the light guide plate. A surface of the reflective film proximate to the light guide plate is provided with a plurality of protruding structures thereon. The plurality of protruding structures extending in a first direction. Tops of at least two of the plurality of protruding structures are uneven.