LED Bin Selection via Phosphor Segmentation
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Solution Overview
Problem
The challenge in mass-producing LED-based lamps for general illumination lies in achieving consistent color temperature, as existing methods require multiple color bins and active feedback mechanisms, which are costly and prone to drift, leading to inconsistent light quality over time.
Innovation Solution
Selecting LED dies and phosphor chips to create independently addressable groups that produce light in specific color regions, allowing for tuning of the net color to a desired white bin by adjusting current delivery, using a robotic pick-and-place system and look-up tables to automate the selection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If white LEDs are binned according to color temperature and LEDs are selected from the desired bin, then consistent color temperature can be achieved, but the yield in any particular bin is relatively low and a large number of bins is required
Solution Approach 1:
The invention segments the white LED into multiple color component LEDs (blue, cyan, green, yellow, orange, red) that can be independently controlled. This segmentation allows each LED to target a specific color bin with high yield, while the combination produces the desired white color temperature, eliminating the need for low-yield white LED binning.
Solution Approach 2:
The invention changes the approach from selecting LEDs based on final white color temperature to selecting LEDs based on their individual color characteristics. By controlling the intensity of each color component independently, the system can achieve precise color temperature control while maintaining high production yield for each color component.
2Temperature
If different colors of light are mixed to produce a desired temperature (e.g., white LEDs plus red LEDs), then the desired color temperature can be achieved, but active feedback mechanisms are required to maintain stability
Solution Approach 1:
The invention performs preliminary action by pre-selecting LEDs with specific color characteristics and pre-configuring their intensity ratios during manufacturing. This allows the desired color temperature to be achieved without requiring active feedback mechanisms during operation, as the color stability is built into the LED selection and configuration.
Solution Approach 2:
The system achieves self-service by using LEDs with inherently stable color characteristics that maintain their emission properties over time. The selected LEDs naturally maintain their color without requiring external feedback control, eliminating the need for sensors, analyzers, and adjustment mechanisms.
3Reliability
If active feedback mechanisms are incorporated to maintain color temperature, then color stability can be maintained, but manufacturing and operating costs are driven up
Solution Approach 1:
The invention extracts and eliminates the complex feedback control system (sensors, analyzers, adjustment mechanisms) from the LED lighting system. Instead, it relies on carefully selected LEDs with stable color characteristics that inherently maintain color stability without requiring these additional components, thereby reducing manufacturing and operating costs.
4Manufacturing precision
If a large number of color bins are required for white LEDs, then consistent color temperature can be achieved, but the yield in any particular bin is relatively low
Solution Approach 1:
The invention segments the white light generation into multiple color component LEDs, each targeting a specific color bin. This allows each color component to be produced in high yield within its specific bin, while the combination of components achieves the desired white color temperature, effectively eliminating the low-yield problem of white LED binning.
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 approach enables reliable tuning of LED-based lamps to a specific white color bin with high yield and minimal perceptible variation, reducing manufacturing costs and improving light consistency by constraining LEDs to non-overlapping source regions in color space.
Implementation Method 1
a first phosphor material and a second phosphor material in the second color-converting layer have different peak emission wavelengths
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
An emitter for an LED-based lighting device has multiple groups of LEDs that are independently addressable, allowing the emitter to be tuned to a desired color bin (e.g., a specific white color) by adjusting the relative current supplied to different groups. The LED dies for the groups and a phosphor chip for each LED die are individually selected such that each LED-die/phosphor-chip combination produces light in a desired source region associated with the group to which the LED belongs. Robotic pick-and-place systems can be used to automate assembly of the emitters by selecting LED dies from a bin based on based on spectral characteristics and phosphor chips from a number of distinct phosphor chip types.