Multi-LED Camera Strobe Packages for Intensity and Color Control
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Solution Overview
Problem
Conventional LED-based camera strobes in portable devices face challenges in achieving higher light output intensity within physical constraints and exhibit a two-tone color combination that is cosmetically undesirable, requiring a solution to provide adjustable intensity and color temperature while maintaining a uniform appearance.
Innovation Solution
The use of multi-LED packages with series-coupled emitting diodes and adjustable current ratio control, combined with multiple phosphor mediums of different colors, allows for adjustable white light output and a uniform cosmetic appearance by controlling the current ratios and phosphor stimulation, enabling higher light intensity and color temperature adjustment within a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If larger LED dies are used to increase light output intensity, then illumination intensity is improved, but device volume increases
Solution Approach 1:
The patent divides the illumination system into multiple separate LED packages, each containing multiple LED dies. Instead of using a single large LED die, the system uses several smaller LED packages (e.g., three packages with multiple LEDs each) that can be arranged in a compact configuration. This segmentation allows the total light output to be increased while maintaining a small overall device volume, as the multiple small packages occupy less space than one large package would require.
2Adaptability or versatility
If multiple phosphor mediums are used to achieve adjustable color temperature, then color temperature adjustability is improved, but cosmetic appearance deteriorates due to two-tone color combination
Solution Approach 1:
The patent applies different phosphor mediums to specific local regions or specific LED dies within the packages. By strategically selecting which phosphors are applied to which LEDs and in what quantities, the system achieves color temperature adjustment while maintaining a uniform overall appearance. The local variation in phosphor composition compensates for the two-tone effect, allowing the combined light from all packages to appear uniform rather than displaying distinct color regions.
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 solution enables higher light output intensity and adjustable color temperature between warm and cool white, while ensuring a uniform color appearance, addressing the constraints of physical space and cosmetic concerns in portable devices.
Implementation Method 1
the phosphor emits secondary, wavelength-converted light at a longer wavelength, such that the combination of the secondary wavelength-converted light and the primary light emitted from the two LED dies structures (typically blue LEDs that are within +/â10 nm, for example) result in a combined, white illumination
Data Source
AI summary
First and second multi-LED packages are installed on a carrier. Each package includes its own emitting diodes that are series coupled to each other and that are encased within a single, internally reflective package having two external terminals. Each package has a light output face from which light, produced by all of the emitting diodes contained therein is emitted in response to a forward current passing through the two terminals. Each package also has phosphor mediums each positioned to be stimulated by primary light of a respective one of its contained emitting diodes, and in response emit secondary wavelength-converted light that emerges from the light output face and is combined with some of the primary light to yield white light. Other embodiments are also described and claimed.