Light emitting device

What is this patent about?

’419 is related to the field of solid-state lighting and color science, specifically addressing the limitations of conventional white LEDs in general illumination. Standard white light sources created by combining blue LED chips with yellow phosphors often suffer from a low Color Rendering Index (CRI) because they lack sufficient spectral density in the longer wavelength regions. This deficiency makes it difficult to accurately represent red tones, which is a critical requirement for high-quality indoor lighting and commercial displays.

The underlying idea behind ’419 is to supplement the spectral gaps of a phosphor-converted white light source by integrating a dedicated long-wavelength emitter directly into the device architecture. Rather than relying solely on the broad but often red-deficient emission of a yellow phosphor, the invention introduces a secondary light source that specifically targets the 560 to 880 nm range. By blending the output of a standard blue-chip/phosphor combination with this targeted red-based emission, the device achieves a more balanced and continuous visible spectrum.

The claims of ’419 focus on a hybrid light emitting device that pairs a first light emitting element, consisting of a blue-emitting chip and a yellow phosphor, with a second light emitting element positioned adjacently. The two elements are electrically coupled in either a series or parallel configuration to operate as a unified light source. The phosphor is specifically layered over the first chip to facilitate wavelength conversion, while the second element provides the necessary spectral compensation to fill out the red end of the light profile.

In practice, the invention can be implemented at either the package level or the chip level. In package-level versions, multiple LED dies are housed within a single molding member, where a blue die is coated with phosphor and a red die is left clear or covered by a secondary protective layer. Alternatively, the technology can be integrated onto a single substrate using monolithic fabrication, where individual light-emitting cells are interconnected via air bridges or step-cover wiring to support high-voltage or AC power operation without requiring external converters.

This approach differs from prior solutions by moving away from simple binary blue-yellow mixing or complex RGB systems that are difficult to balance. By using the second element as a spectral compensator, the device overcomes the inherent 'red hole' found in common white LEDs. Furthermore, the ability to connect these diverse emitters in reverse parallel arrays allows the device to be driven directly by AC power sources, reducing flicker and eliminating the need for bulky driver electronics while maintaining superior color fidelity.