Backlight Module Polarization and Scratch Protection
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Solution Overview
Problem
Backlight modules with reverse prism sheets suffer from low light energy utilization due to polarizability issues and production yield challenges, as the light emitting surface of the light guide plate can be scratched by the prism structures, leading to inefficient light distribution and high light loss after passing through a display panel with a polarizer.
Innovation Solution
A backlight module design incorporating a light guide plate, a first optical film with specific polarization components, and a second optical film with prism structures aligned at a shallow angle to the light guide plate, preventing direct contact and enhancing light polarization and utilization, while maintaining production yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If reverse prism sheet is used to replace two laminated optical BEFs, then light collection near normal viewing angle is improved, but light emitting surface of light guide plate is easily scratched by prism structures
Solution Approach 1:
The patent introduces a protective film as an intermediary layer between the reverse prism sheet and the light guide plate. This protective film prevents direct contact between the sharp prism structures and the light guide plate surface, eliminating the scratching problem while maintaining the light collection performance of the reverse prism sheet.
Solution Approach 2:
The patent applies a protective film on the light guide plate surface before assembling the reverse prism sheet. This beforehand cushioning approach ensures that the light guide plate surface is protected from potential damage during assembly and operation, preventing scratches that would affect production yield.
2Illumination intensity
If reverse prism sheet is used to increase total light output, then light converging characteristic is improved, but light beam polarizability is low causing large light energy loss
Solution Approach 1:
The patent modifies the optical parameters of the system by introducing a polarization conversion film that changes the polarization state of light. This film converts unpolarized or randomly polarized light into linearly polarized light with a specific orientation, increasing light beam polarizability and reducing energy loss after passing through the display panel polarizer.
Solution Approach 2:
The patent creates a composite optical system by combining the reverse prism sheet with a polarization conversion film. This composite structure integrates the light collection function of the reverse prism sheet with the polarization control function of the film, achieving both high light output and improved polarizability simultaneously.
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 design significantly increases the light energy utilization rate by optimizing light polarization and distribution, reducing light loss, and preventing scratches on the light guide plate, thereby improving the overall performance and production efficiency of the backlight module.
Implementation Method 1
The illumination beam has a first polarization component parallel to a virtual surface and a second polarization component perpendicular to the virtual surface after passing through the first optical film
Implementation Method 2
The second optical film includes a substrate and a plurality of prism structures. The prism structures are disposed on one side of the substrate of the second optical film facing the light guide plate
Data Source
AI summary
A backlight module includes a light guide plate, a light source, a first optical film, and a second optical film. The light source is disposed on one side of a light incident surface of the light guide plate. The first optical film is disposed between the light guide plate and the second optical film. An illumination beam from the light source has a first polarization component and a second polarization component perpendicular to the first polarization component. A ratio of the first polarization component to the second polarization component is greater than or equal to 1.2 and less than or equal to 10. The second optical film includes a substrate and a plurality of prism structures disposed between the substrate and the light guide plate. An included angle between an extending direction of the prism structures and the light incident surface is less than 5 degrees.