Multistack LED Layout for Uniform Color and Luminous Intensity
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Solution Overview
Problem
Conventional light-emitting diode (LED) arrays experience decreased luminous intensity due to light absorption between units and poor uniformity in optical and electrical characteristics, primarily caused by the etching process used to define light-emitting diode units, leading to variations in devices formed from different parts of the substrate.
Innovation Solution
A light-emitting device comprising multiple semiconductor stacks on a substrate, where each stack is separated by distinct bonding layers of varying thicknesses, allowing for classification into regions based on luminous intensity and wavelength, enabling rearrangement and reallocation to improve uniformity and reduce light absorption, thereby enhancing overall luminous intensity and optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an etching process is used to form trenches between light-emitting diode units, then the light-emitting diode units are electrically insulated from each other, but the overall luminous intensity decreases due to light absorption between units
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of LED units with trenches to a three-dimensional stacked configuration where multiple semiconductor stacks are vertically arranged on the substrate. This vertical stacking eliminates the need for lateral trenches, removing the light absorption problem while maintaining electrical insulation through the bonding layer structure.
Solution Approach 2:
The patent implements a nested structure where multiple semiconductor stacks are vertically integrated on the same substrate area. Each stack contains complete LED units with p-type and n-type semiconductor layers, and they are nested in the vertical dimension through bonding layers, effectively stacking functional units without lateral separation trenches.
2Productivity
If light-emitting diode units are formed from different parts of the substrate, then the device can be manufactured, but there is poor uniformity between devices on optical characteristics or electrical characteristics
Solution Approach 1:
The patent applies local quality by forming multiple semiconductor stacks from a specific localized region of the substrate where uniformity is ensured. By concentrating all LED units in vertically stacked configuration from a controlled substrate area rather than distributing them across the entire substrate, the variation in optical and electrical characteristics is minimized.
Solution Approach 2:
The patent performs preliminary classification and selection of substrate regions before forming the semiconductor stacks. By pre-identifying and using a uniform region of the substrate for all stack formations, the invention ensures consistent optical and electrical characteristics across all devices while maintaining manufacturing efficiency.
3Manufacturing precision
If multiple semiconductor stacks are arranged on a substrate with bonding layers of varying thicknesses, then uniformity in luminous intensity can be improved, but the device complexity increases
Solution Approach 1:
The patent utilizes parameter changes by varying the thickness of bonding layers between semiconductor stacks to achieve uniform luminous intensity output. By adjusting the bonding layer thickness parameter, the invention compensates for variations in LED unit characteristics, ensuring consistent optical performance across all stacks while maintaining a relatively simple overall structure.
Data Source
AI summary
The present disclosure provides a light-emitting device comprising a substrate with a topmost surface; a first semiconductor stack arranged on the substrate, and comprising a first top surface separated from the topmost surface by a first distance; a first bonding layer arranged between the substrate and the first semiconductor stack; a second semiconductor stack arranged on the substrate, and comprising a second top surface separated from the topmost surface by a second distance which is different form the first distance; a second bonding layer arranged between the substrate and the second semiconductor stack; a third semiconductor stack arranged on the substrate, and comprising third top surface separated from the topmost surface by a third distance; and a third bonding layer arranged between the substrate and the third semiconductor stack; wherein the first semiconductor stack, the second semiconductor stack, and the third semiconductor stack are configured to emit different color lights.