Monolithic LED Backlight with Collimator and Microlens Array
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Solution Overview
Problem
Conventional optical illumination devices for digital displays are bulky, heavy, and inefficient, requiring full illumination of the display panel even when only a partial image is needed, which wastes energy and increases manufacturing costs due to numerous components.
Innovation Solution
An LED backlight comprising a monolithic LED array, a monolithic collimator array that collimates light to angles of +/−50°, and a microlens array that focuses light to infinity, combined with a relay lens to provide a compact, efficient, and uniform light source, allowing for selective illumination of display panel portions and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional illumination devices use multiple separate components (fly's eye lenses, homogenising rods, separate RGB LEDs), then light homogenisation and colour mixing are achieved, but device size, weight, and manufacturing complexity increase significantly
Solution Approach 1:
The patent combines multiple separate optical components (fly's eye lenses, homogenising rods) and light sources (separate RGB LEDs) into integrated monolithic structures. The monolithic LED array integrates multiple LED types on a single substrate, while the monolithic fly's eye lens array integrates multiple lens functions in one piece, reducing component count and assembly complexity while maintaining light homogenisation effectiveness
2Illumination intensity
If conventional devices illuminate the entire display panel, then uniform brightness is achieved, but energy consumption increases when only partial display areas are needed
Solution Approach 1:
The monolithic LED array is divided into multiple independently controllable LED groups or individual LEDs that correspond to different display regions. This segmentation allows selective activation of only those LED groups needed for the current display content, enabling partial illumination mode that reduces power consumption while maintaining brightness uniformity in the active display area
Solution Approach 2:
The illumination system transitions from static full-panel illumination to dynamic selective illumination. The control system dynamically determines which portions of the display panel require illumination based on content analysis, and accordingly activates only the corresponding LED groups, adapting power consumption to actual display needs while maintaining brightness uniformity where required
3Weight of stationary object
If monolithic LED arrays and collimator arrays are used, then device size and weight are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The monolithic LED array and monolithic collimator array are designed as integrated units with pre-established geometric relationships. The collimator array is fabricated as a single piece with channels or lenses precisely positioned relative to the LED array structure, eliminating the need for post-assembly alignment between separate components. This integration reduces weight while maintaining the necessary optical alignment through monolithic fabrication processes
4Illumination intensity
If separate RGB LEDs are used instead of a single white LED, then colour quality improves, but the illumination device becomes more complex as individual light sources must be combined into the same optical path
Solution Approach 1:
Multiple separate RGB LED light sources are merged into a single monolithic LED array structure where red, green, and blue LEDs are arranged in a regular pattern on one substrate. This integration allows all colour channels to share common optical components (collimator array, fly's eye lenses, homogenising structures) and a unified optical path, maintaining colour quality while reducing the complexity of combining separate light sources
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 results in a smaller, lighter, and more energy-efficient illumination system that maintains brightness and image quality while allowing for energy savings by illuminating only the required display areas, enhancing durability and reducing manufacturing costs.
Implementation Method 1
the collimating channels are configured to collimate emitted light emitted from the LEDs to angles in the range of about +/−50° from a line substantially normal to the surface of the LED array
Implementation Method 2
a microlens array for focusing the collimated light to infinity
Data Source
AI summary
An LED backlight for use with a display panel, the backlight comprising a monolithic LED array having a surface and comprising a plurality of LEDs for emitting light from the surface of the array; a monolithic collimator array comprising a plurality of collimating channels, and being aligned so that each of the collimating channels is aligned with one or more of the plurality of LEDs, wherein the collimating channels are configured to collimate emitted light emitted from the LEDs to angles in the range of about +/−50° from a line substantially normal to the surface of the LED array; a microlens array for focusing the collimated light to infinity, the microlens array comprising a plurality of lenslets, each lenslet aligned with a collimating channel of the monolithic collimator array; and a relay lens for focusing the light from the microlens array on a display panel.