Backlight Reflective Sheet with Light Conversion Coating for Edge Light Mixing
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Solution Overview
Problem
Current flat panel displays with backlight modules experience light leakage and uneven brightness due to poor light mixing at the edges, affecting color uniformity, especially in narrow frame designs.
Innovation Solution
A display device with a backlight module that includes a matrix of light sources and a reflective sheet with a light conversion coating of varying dot sizes, where the reflective sheet is positioned around or on the corners of the light sources, enhancing light distribution and mixing to prevent light leakage and improve color uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the frame of the display is made narrower to meet design requirements, then the display can achieve more compact design, but the light mixing effect at the edge of the backlight module deteriorates, causing light leakage and affecting color uniformity
Solution Approach 1:
A reflective sheet is introduced as an intermediary component between the backlight module and the display panel. This reflective sheet includes a light conversion coating that converts blue light from LEDs to green light, and a reflective surface that redirects light. The intermediary structure enables effective light mixing at the edges without requiring a wider frame, thus resolving the contradiction between narrow frame design and good light mixing effect.
Solution Approach 2:
The patent changes the optical parameters by using a light conversion coating with specific dot sizes (5-50 micrometers) that have different light conversion efficiencies. By controlling the size distribution of these dots, the patent optimizes the light conversion effect and improves light mixing at the edges, allowing narrow frame design while maintaining good optical performance.
2Illumination intensity
If blue LEDs are used as light source to increase brightness and make light output more uniform, then the backlight module achieves higher brightness, but light leakage at the edge occurs due to poor light mixing effect
Solution Approach 1:
The patent uses a light conversion coating that changes the color of light from blue (LEDs) to green. This color conversion helps in improving light mixing at the edges because green light has different propagation characteristics compared to blue light. The reflective surface further enhances this effect by redirecting the converted light, thereby preventing light leakage while maintaining high brightness.
Solution Approach 2:
The reflective sheet acts as an intermediary that receives blue light from LEDs and converts it to green light through the light conversion coating. This intermediary structure improves light mixing at the edges and prevents light leakage, allowing the use of high-brightness blue LEDs without the harmful light leakage effect.
3Productivity
If the reflective sheet is positioned closer to the matrix of light sources, then the light conversion effect is enhanced, but the light mixing effect at the edge deteriorates
Solution Approach 1:
The patent positions the reflective sheet at an inclined angle (45 degrees or less) relative to the matrix of light sources, introducing a dimensional component that allows light to travel along the reflective surface. This angled positioning enables the light conversion coating to effectively convert light while the reflective surface guides the light to mix properly at the edges, resolving the contradiction between close positioning for conversion efficiency and proper positioning for light mixing.
Solution Approach 2:
The light conversion coating is applied only in specific regions (5-50 micrometers dot sizes) rather than uniformly across the entire reflective sheet. This local quality approach allows different regions to serve different functions: the coated regions perform light conversion while the uncoated reflective regions maintain light mixing capability, thus resolving the contradiction between conversion efficiency and light mixing effect.
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 addresses light leakage and uneven brightness issues by uniformly distributing light across the display panel, enhancing color uniformity and preventing hot spots, thereby improving the overall optical characteristics of the display device.
Implementation Method 1
a light conversion coating having a plurality of dots of different sizes is formed on the reflective surface, the matrix of light sources emits a first light toward the reflective sheet, and the first light is changed by the light conversion coating to form a second light, wherein the first light and the second light are of different colors
Implementation Method 2
The reflective sheet is arranged around or on at least one corner of the matrix of light sources, the reflective sheet has an upper edge, a reflective surface and a lower edge
Data Source
AI summary
A display device includes a display panel and a backlight module. The backlight module is arranged under the display panel. The backlight module includes a matrix of light sources and a reflective sheet. The reflective sheet is disposed around or on at least one corner of the matrix of light sources. The reflective sheet has an upper edge, a reflective surface and a lower edge. The upper edge is far away from the matrix of light sources relative to the lower edge. A light conversion coating having a plurality of dots of different sizes is formed on the reflective surface. The matrix of light sources emits a first light toward the reflective sheet, and the first light is changed by the light conversion coating to form a second light, wherein the first light and the second light are of different colors.