Backlight Module Segmented Light Guide for Anti-Peeping Brightness
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Solution Overview
Problem
Existing liquid crystal display devices with anti-peeping modes suffer from reduced brightness due to the inclusion of anti-peeping sheets, leading to increased power consumption and costs, as well as a thicker overall structure.
Innovation Solution
A backlight module comprising a light guide assembly with overlapped thinner first light guide plates, a first light source, a second light guide plate, a second light source, and a turning film, along with an optional anti-peeping sheet and reflective sheet, to improve light utilization ratio and maintain brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an anti-peeping sheet is arranged in the backlight module to achieve anti-peeping effect, then the anti-peeping function is improved, but the brightness of the backlight module decreases
Solution Approach 1:
The light guide plate is divided into multiple light guide regions (first light guide region, second light guide region, third light guide region) with different microstructure arrangements. Each region has specific microstructures (first microstructures, second microstructures, third microstructures) that control light distribution differently, allowing the anti-peeping sheet to be positioned in regions where it causes minimal brightness loss while maintaining its anti-peeping function.
Solution Approach 2:
Different regions of the light guide plate are designed with different local optical properties through varying microstructure types and distributions. The first light guide region has microstructures optimized for general illumination, while the second and third regions have microstructures specifically designed to work with the anti-peeping sheet, creating local optical zones that minimize the negative impact of the anti-peeping sheet on overall brightness.
2Illumination intensity
If the power of the light source is increased to maintain original brightness with an anti-peeping sheet, then the brightness is maintained, but the cost and thickness of the backlight module increase
Solution Approach 1:
Instead of increasing light source power, the invention changes the optical parameters of the light guide plate by introducing multiple types of microstructures with different geometries and distributions. These parameter changes in the light guide plate's optical properties enable more efficient light utilization, compensating for the brightness loss caused by the anti-peeping sheet without requiring higher power consumption or additional components that would increase cost and thickness.
3Loss of energy
If multiple types of microstructures are arranged on the light guide plate to improve light utilization, then the light utilization ratio is improved, but the manufacturing complexity increases
Solution Approach 1:
The light guide plate is segmented into distinct regions, each containing a specific type of microstructure. This segmentation allows for standardized manufacturing of different microstructure types that can be produced separately and then assembled or formed into the complete light guide plate, reducing the overall manufacturing complexity compared to creating all microstructure types in a single complex process.
Solution Approach 2:
The microstructures are designed as periodic or quasi-periodic patterns that can be formed using conventional molding or etching techniques. These structured patterns, while diverse in type, follow regular geometric principles that facilitate manufacturing through standard industrial processes, balancing optical performance with ease of production.
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 proposed backlight module enhances light utilization ratio and maintains brightness in both anti-peeping and sharing modes, reducing power consumption and costs while minimizing structural thickness.
Implementation Method 1
each of the first light guide plates has a first bottom surface and a first light-emitting surface opposite to each other, and a first light-incident surface connecting the first bottom surface to the first light-emitting surface. The first bottom surface is provided with a plurality of first microstructures.
Implementation Method 2
a reflective sheet, arranged on a side, away from the second light guide plate, of the light guide assembly
Implementation Method 3
The second light guide plate has a second bottom surface and a second light-emitting surface opposite to each other, and a second light-incident surface connecting the second bottom surface to the second light-emitting surface, and the second bottom surface faces the light guide assembly and is provided with a plurality of second microstructures.
Implementation Method 4
The turning film is arranged between the light guide assembly and the second light guide plate
Data Source
AI summary
A backlight module includes a light guide assembly, a first light source, a second light guide plate, a second light source, and a turning film. The light guide assembly includes a plurality of overlapped first light guide plates. Each first light guide plate has a first bottom surface, a first light-emitting surface, and a first light-incident surface. The first bottom surface has first microstructures. The first light source is arranged next to first light-incident surfaces of the first light guide plates. The second light guide plate is arranged above the light guide assembly and has a second bottom surface, a second light-emitting surface, and a second light-incident surface. The second bottom surface has second microstructures. The second light source is arranged next to the second light-incident surface of the second light guide plate. The turning film is arranged between the light guide assembly and the second light guide plate.