Planar LED Array with Uniform Active Layer Height for Sharp Image Focusing
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Solution Overview
Problem
Conventional multicolor LED arrays face difficulties in focusing lights of different colors onto a photosensitive material due to varying light emitting positions, resulting in challenges in forming sharp images.
Innovation Solution
The LED array design includes semiconductor substrates with first LED portions emitting a predetermined color and second LED portions of different colors, where the active layers of both types are at the same height, ensuring uniform distances to the photosensitive material, and a driving circuit controls the LEDs based on image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional multicolor LED array structure is used with layered organic layers (red, green, blue) on an electron transport layer, then multiple colors can be emitted from a single device, but the light emitting positions of different colors are at different heights making it difficult to focus all lights on the photosensitive material surface
Solution Approach 1:
The patent transitions from a vertical stacking approach (layered organic layers at different heights) to a planar arrangement approach (multiple LED arrays arranged side-by-side on the same plane). This dimensional change allows all light emitting positions to be at the same height, enabling simultaneous focusing of all colors on the photosensitive material surface while maintaining multicolor emission capability
Solution Approach 2:
The patent divides the multicolor LED array into multiple independent LED arrays, each responsible for emitting a specific color. These segmented arrays are arranged in the scanning direction, with each array containing LEDs of a predetermined color. This segmentation allows precise control of each color's emission position and timing while maintaining uniform emission height across all arrays
2Adaptability or versatility
If LEDs of different colors are arranged at different heights to achieve multicolor emission, then color diversity is achieved, but the distances from light emitting positions to the photosensitive material surface become different preventing sharp image formation
Solution Approach 1:
The patent resolves the height difference issue by arranging multiple LED arrays side-by-side on the same plane rather than stacking them vertically. This planar arrangement ensures that all light emitting positions, regardless of color, are at the same height from the photosensitive material surface, enabling precise focusing of all colors simultaneously
Solution Approach 2:
The patent creates an equipotential emission surface by positioning all LED arrays at the same height level. This ensures that light from all colors travels the same distance to reach the photosensitive material, eliminating focus errors and enabling sharp image formation while maintaining color diversity
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 allows for the formation of sharp images by ensuring consistent light exposure distances across different color LEDs, enhancing image sharpness and resolution.
Implementation Method 1
a plurality of first LED portions formed integrally on a surface of the semiconductor substrate. The first LED portions emit light of a predetermined color. The LED array further includes a plurality of second LED portions fixed to the semiconductor substrate
Implementation Method 2
The first LED portions emit light of a predetermined color. The second LED portions emit light whose color is different from the first LED portions
Data Source
AI summary
An LED array includes a semiconductor substrate and a plurality of first LED portions formed integrally on a surface of the semiconductor substrate. The first LED portions emit light of a predetermined color. The LED array includes a plurality of second LED portions fixed to the semiconductor substrate and are disposed corresponding to the first LED portions. The second LED portions emit light whose color is different from the first LED portions. The second LED portions are so disposed that active layers of the second LED portions are substantially at the same height as active layers of the first LED portions.