Backlight Unit with Varying Convex Lens Height-to-Pitch Ratios
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing backlight units for notebook computers face challenges in minimizing LED hot spot mura and side light leakage while maintaining a thin profile and low power consumption, as the use of LEDs as light sources results in non-uniform light distribution and light emission from the sides due to the angle of refracted light.
Innovation Solution
A backlight unit design featuring a light guide plate with optical microstructures comprising convex lens members, where the height-to-pitch ratios and distribution density of these microstructures vary between the center and side regions, effectively scattering light to reduce side light leakage and minimize LED hot spot mura by optimizing the arrangement of light sources and microstructures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of LEDs is decreased to save power and reduce weight, then power consumption and device weight are reduced, but LED hot spot mura problem worsens
Solution Approach 1:
The patent applies local quality by varying the height-to-pitch ratios of convex lens members in different regions (center vs. side regions) of the light guide plate. The center region has larger height-to-pitch ratios to control light from centrally positioned LEDs, while side regions have smaller ratios to manage light from side LEDs, thereby achieving uniform light distribution with fewer LEDs
Solution Approach 2:
The patent changes the geometric parameters (height and pitch) of the convex lens members to optimize light distribution. By adjusting these parameters spatially across the light guide plate, the system achieves uniform illumination without requiring a high density of LEDs, thus reducing power consumption while maintaining reliability
2Length of moving object
If the mixed light region is decreased to save space, then the display panel can be made thinner, but LED hot spot mura problem worsens
Solution Approach 1:
The patent implements local quality by creating spatially varying convex lens structures with different height-to-pitch ratios in the light guide plate. This allows the system to achieve uniform light distribution within a shorter mixed light region by locally optimizing the optical microstructure rather than relying on a long gradual transition zone
Solution Approach 2:
The patent applies preliminary action by pre-configuring the convex lens members with specific height-to-pitch ratios at different locations in the light guide plate before light enters. This preliminary structural arrangement ensures that light is properly distributed from the outset, eliminating the need for a long mixed light region and enabling thinner panel designs
3Reliability
If microstructures are added at the light entry side to reduce LED hot spot mura, then light distribution uniformity is improved, but side light leakage worsens
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying convex lens members. The center region has larger height-to-pitch ratios to address LED hot spot mura, while side regions have smaller ratios to prevent side light leakage. This localized optimization allows the system to achieve uniform light distribution without generating excessive side light
Solution Approach 2:
The patent changes the geometric parameters of the optical microstructures across different regions. By varying height and pitch ratios spatially, the system optimizes light refraction at different locations, achieving uniform distribution in the center while minimizing side light emission from the edges
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
This design effectively reduces LED hot spot mura and side light leakage, enabling a high-brightness and high-quality display with fewer LEDs, suitable for thin frame applications while maintaining power efficiency and reducing the number of LEDs and mixed light regions.
Implementation Method 1
After light enters a light guide plate, according to Snell's law the light will be more concentrated
Implementation Method 2
The optical microstructure includes a plurality of convex lens members... effectively scattering light to reduce side light leakage and minimize LED hot spot mura
Data Source
AI summary
A backlight unit includes a light guide plate and a plurality of light sources. A side of the light guide plate is provided with an optical microstructure including a plurality of convex lens members aligned along the side. The height-to-pitch ratios of the convex lens members in the central region of the optical microstructure are different from those of the convex lens members in the side regions of the optical microstructure. For example, the height-to-pitch ratios of the convex lens members in the central region of the optical microstructure are larger than the height-to-pitch ratios of the convex lens members in the side regions of the optical microstructure. The light sources may be light emitting diodes (LED) directed toward the optical microstructure.