Optical Lens for LED Backlight Uniformity
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Solution Overview
Problem
Conventional light emitting diode (LED) backlight units for LCDs suffer from uneven light distribution, leading to increased thickness and hot spots in displays due to the domed lens design, which limits the ability to achieve uniform light characteristics and results in picture quality degradation.
Innovation Solution
An optical lens with a reflection surface and a bottom refraction surface is used to redirect light emitted upwards from the LED, ensuring it is refracted and reflected towards the lateral surface, reducing upward light emission and increasing lateral light distribution, thereby minimizing hot spots and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a domed lens is used with a light emitting diode, then the light can be distributed within a predetermined region, but the light characteristic becomes uneven and hot spots are generated
Solution Approach 1:
The lens is divided into multiple functional regions: a reflection surface region and a refraction surface region. The reflection surface reflects light at specific angles, while the refraction surface refracts light at different angles, segmenting the light distribution function to achieve uniform illumination and eliminate hot spots
Solution Approach 2:
Different regions of the lens are assigned different optical properties. The reflection surface has specific reflectivity characteristics while the refraction surface has specific refraction characteristics, allowing each region to perform its specialized function for optimal light distribution
2Illumination intensity
If a domed lens is used with a light emitting diode, then light can be emitted in a predetermined direction, but the thickness of the backlight unit increases
Solution Approach 1:
Instead of using a conventional domed lens shape, the invention inverts the approach by creating a lens with a reflection surface and a refraction surface that work together to achieve the desired light directionality with reduced thickness, eliminating the need for hot spot baffle plates
3Manufacturing precision
If hot spot baffle plates are added to eliminate hot spots, then light uniformity improves, but the assembly process becomes more complex and thickness increases
Solution Approach 1:
The invention merges the hot spot elimination function directly into the lens structure by integrating the reflection surface and refraction surface. This combines multiple functions (light distribution, hot spot elimination, and directional control) into a single component, eliminating the need for separate hot spot baffle plates and simplifying the assembly process
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 hot spots and enhances light uniformity, simplifies the assembly process by eliminating the need for hot spot baffle plates, and decreases the overall thickness of the display panel.
Implementation Method 1
a reflection surface formed thereon for reflecting light emitted upwards from thereunder
Implementation Method 2
a bottom refraction surface for refracting the light emitted upwards from thereunder and allowing the light to reach the reflection surface
Data Source
AI summary
An optical lens, a light emitting device package using the optical lens and a backlight unit are disclosed, whereby light irradiated upward of a light emitting device is refracted from a bottom refraction surface to allow reaching a reflection surface, and an optical lens is mounted for reflecting the light sideways of the lens from the reflection surface to minimize an amount of light irradiated upward of the lens while increasing the amount of light irradiated toward the lateral surface of the lens, thereby limiting the generation of a hot spot to the maximum. The present invention dispenses with a hot spot baffle plate and a complicated assembly process to enable to reduce the number of parts and to decrease the thickness of a panel.