Backlight Module Prism Structures Anti-Peeping Brightness
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Solution Overview
Problem
Conventional backlight modules for LCD screens suffer from reduced brightness and inadequate anti-peeping functionality due to light being reflected back and forth between the prism sheet and reflector, leading to energy loss and easy visibility of screen contents from larger angles.
Innovation Solution
A backlight module comprising a light guide plate, a prism sheet with first prism structures, and a reflective film with second prism structures and a light absorbing layer, which directs light out at a reduced angle by reflecting and absorbing light to minimize energy loss and visibility beyond a certain angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional light guide plate with microstructure is used to direct light out, then light can be directed out through the light exit surface, but light is reflected back and forth between the prism sheet and reflector causing energy loss and reduced brightness
Solution Approach 1:
The patent extracts the problematic reflective film from the optical path by placing it on the light incident surface rather than having light reflect between the prism sheet and reflector. The reflective film with prism structures directs light outward immediately, preventing multiple reflections and energy loss.
Solution Approach 2:
The reflective film acts as an intermediary component between the light source and the light guide plate. It receives light from the light source and redirects it into the light guide plate at optimal angles, preventing the light from reflecting back and forth between other components.
2Adaptability or versatility
If light is allowed to emit at larger angles through the upper diffuser, then more viewing area is covered, but the LCD screen contents become easily visible to others and lack anti-peeping function
Solution Approach 1:
The patent applies different prism structures at different locations: the reflective film on the light incident surface has prism structures oriented to control backward reflection, while the prism sheet on the light exit surface has prism structures oriented to control forward light emission. This local differentiation achieves both brightness and anti-peeping functions.
Solution Approach 2:
Instead of using a single diffuser layer that scatters light in all directions, the patent inverts the approach by using prism structures that actively direct light at specific angles. The prisms on the reflective film direct light forward, while the prisms on the prism sheet further control the emission angle, creating a narrow viewing cone that provides anti-peeping function.
3Illumination intensity
If a reverse prism sheet is used to provide higher brightness and lower light-emitting angle, then brightness is improved, but anti-peeping function is still insufficient
Solution Approach 1:
The patent merges two prism sheet functions into one integrated solution: the reflective film with prism structures serves both as a reflective surface and a light-directing element. By combining the reflection function and the angle-control function into a single component, the patent achieves superior brightness and anti-peeping performance compared to using a reverse prism sheet alone.
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 enhances brightness and provides an improved anti-peeping function by reducing the light-emitting angle, making it difficult for others to view the screen content beyond a specific range, while maintaining a brightness only 2% lower than conventional modules.
Implementation Method 1
The reflective film is disposed on the reflection surface of the light guide plate. The reflective film includes a film body, a plurality of second prism structures that are disposed on the film body and that protrude from the film body toward the reflection surface
Implementation Method 2
a light absorbing layer that is disposed on the film body opposite to the second prism structures
Implementation Method 3
The prism sheet is disposed on the light exit surface of the light guide plate, and includes a plurality of first prism structures that protrude toward the light exit surface of the light guide plate
Data Source
AI summary
A backlight module includes a light guide plate, a light source, a prism sheet, and a reflective film. The light source is disposed on a light-incident surface of the light guide plate. The prism sheet is disposed on a light exit surface of the light guide plate, and includes a plurality of first prism structures that protrude toward the light exit surface of the light guide plate. The reflective film is disposed on a reflection surface of the light guide plate, and includes a film body, a plurality of second prism structures that are disposed on the film body and that protrude from the film body toward the reflection surface, and a light absorbing layer that is disposed on the film body opposite to the second prism structures.