Stacked LED Pixel Structure for RGB Mixing and Light Isolation
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Solution Overview
Problem
Conventional LED display apparatuses face challenges in reducing the size of LED chips to fit more sub-pixels in a restricted area, maintaining high-quality white light with appropriate RGB mixing ratios, and minimizing light interference between pixels due to differences in luminous intensity and viewing angles.
Innovation Solution
A display apparatus with a light emitting device configuration that includes a display substrate, light emitting devices, a light blocking layer, and a transparent layer, where the light emitting devices are stacked with a black molding layer to block light and a transparent layer to transmit light, allowing for reduced chip size, controlled RGB mixing, and adjusted viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If one LED chip is arranged in each sub-pixel on a two-dimensional plane, then the display apparatus can show various colors, but the number of LED chips increases and requires excessive mounting time
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of LED chips to a three-dimensional stacked configuration. Multiple LED chips emitting different colors (blue, green, red) are vertically stacked within a single pixel unit, enabling full-color display while reducing the number of chips required per unit area and simplifying the mounting process.
Solution Approach 2:
The patent combines multiple LED chips of different colors into a single integrated light emitting device. By stacking blue, green, and red LED chips vertically and using a color conversion layer, the device merges their functions to produce various colors, reducing the total number of separate chips needed.
2Area of stationary object
If the area of each LED chip is reduced to fit more sub-pixels in a restricted area, then more pixels can be arranged, but mounting becomes more difficult and luminous area decreases
Solution Approach 1:
The patent uses vertical stacking to increase pixel density without reducing LED chip area. By arranging multiple LED chips in the vertical dimension rather than compressing them horizontally, each chip maintains its optimal size for easy mounting while achieving higher pixel density through the third dimension.
3Illumination intensity
If the viewing angle of light emitted from one pixel is increased, then light coverage is improved, but interference between adjacent pixels occurs and image quality deteriorates
Solution Approach 1:
The patent applies different properties to different parts of the light emitting device. The color conversion layer has spatially varying characteristics that selectively convert wavelengths in different directions, allowing wide viewing angles while preventing color interference between adjacent pixels through localized wavelength conversion.
4Illumination intensity
If conventional LED chips with high blue luminous intensity are used, then blue light output is strong, but it is difficult to match the standard RGB mixing ratio of 3:6:1
Solution Approach 1:
The patent changes the physical parameters of the light emitting device by incorporating a color conversion layer with specific optical properties. This layer converts excess blue light into green and red wavelengths, adjusting the overall spectral output to match the standard RGB mixing ratio while maintaining strong blue light emission from the LED chips.
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 configuration increases the area of each sub-pixel, reduces the time required for the mounting process, allows for easier control of the RGB mixing ratio, and adjusts the viewing angles of emitted light to minimize interference, resulting in improved image quality and efficiency.
Implementation Method 1
a light blocking layer disposed between the light emitting devices
Implementation Method 2
a transparent layer covering the light emitting devices and the light blocking layer
Implementation Method 3
at least one of the light emitting devices includes a first LED sub-unit, a second LED sub-unit disposed on the first LED sub-unit, and a third LED sub-unit disposed on the second LED sub-unit
Data Source
AI summary
A display apparatus including a display substrate, light emitting devices disposed on the display substrate, circuit electrodes disposed between the light emitting devices and the display substrate, and a transparent layer covering the light emitting devices and the circuit electrodes, in which at least one of the light emitting devices includes a first LED sub-unit configured to emit light having a first wavelength, a second LED sub-unit adjacent to the first LED sub-unit and configured to emit light having a second wavelength, a third LED sub-unit adjacent to the second LED sub-unit and configured to emit light having a third wavelength, and a substrate disposed on the third LED sub-unit, in which a difference in refractive indices between the transparent layer and air is less than a difference in refractive indices between the substrate and a semiconductor layer of the third LED sub-unit.