LED Chip Indentations for Uniform Current Distribution
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Solution Overview
Problem
Conventional LED chips have limited emission efficiency due to restricted current flow and emission area, primarily under the second electrode, which results in reduced light emission from regions farther away.
Innovation Solution
The LED chip design incorporates a first semiconductor layer, an active layer, a second semiconductor layer, and a plurality of indentations with a first metal layer that extends to the bottom and sides of these indentations, isolated by insulating layers, allowing for even current distribution and increased light emission area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current flows vertically from the second electrode through the second semiconductor layer to the active layer, then the current path is shortest and most direct, but the emission area is restricted to a region just below the second electrode and the neighborhood
Solution Approach 1:
The second semiconductor layer is segmented by creating multiple indentations that extend downward to expose the first semiconductor layer. These indentations divide the continuous current path into multiple distributed paths, allowing current to flow through both the second and first semiconductor layers across a broader area, thereby expanding the emission region beyond what is possible with a single vertical current path.
Solution Approach 2:
The invention transitions from a purely vertical current flow (one-dimensional) to a three-dimensional current distribution by creating indentations that extend downward and exposing the first semiconductor layer. This dimensional change allows current to flow laterally through the first semiconductor layer in addition to the vertical path, significantly expanding the effective emission area.
2Illumination intensity
If the active layer emission area is expanded to increase light output, then more light is emitted, but current distribution becomes uneven with less current reaching farther regions
Solution Approach 1:
The indentations create locally different current distribution characteristics across the LED chip. Regions with indentations allow current to flow through both semiconductor layers, while regions without indentations maintain the standard vertical current path. This local variation in current flow paths ensures uniform current distribution across the entire active layer, preventing current concentration in specific areas and enabling even light emission across the expanded emission area.
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 design enhances light emission efficiency by distributing current evenly across the active layer, increasing the emission area and light extraction efficiency, while preventing short circuits and maintaining light transmission through transparent conductive layers.
Implementation Method 1
a first metal layer disposed on the second semiconductor layer and electrically connecting to the first semiconductor layer
Implementation Method 2
When a voltage is applied to the semiconductor, electrons and holes meet and recombine under electrode voltage difference. At this moment, the electrons fall to the lower energy level and the energy is released in the form of photons.
Implementation Method 3
a first insulating layer deposited on the second semiconductor layer and between the first metal layer and the second semiconductor layer to isolate the first metal layer from the second semiconductor layer
Data Source
AI summary
A LED chip including a first semiconductor layer; an active layer; a second semiconductor layer; a plurality of indentations, wherein each indentation extends downward to reach and expose the first semiconductor layer, wherein each indentation includes a bottom part and two side surfaces in a cross sectional view; an exposing area exposing the first semiconductor layer at a side of the LED chip; a first metal layer disposed on the second semiconductor layer and electrically connecting to the first semiconductor layer; and a first insulating layer formed between the first metal layer and the second semiconductor layer to isolate the first metal layer from the second semiconductor layer; wherein the first metal layer continuously extends to the plurality of indentations, covers the bottom part, the two side surfaces of each indentation and a top surface of the second semiconductor layer around the two side surfaces and contacts the exposing area; and wherein the first metal layer includes a plurality of recesses corresponding to the plurality of indentations.