Abstract:
A method for fabricating an LED/phosphor structure is described where an array of blue light emitting diode (LED) dies are mounted on a submount wafer. A phosphor powder is mixed with an organic polymer binder, such as an acrylate or nitrocellulose. The liquid or paste mixture is then deposited over the LED dies or other substrate as a substantially uniform layer. The organic binder is then removed by being burned away in air, or being subject to an O2 plasma process, or dissolved, leaving a porous layer of phosphor grains sintered together. The porous phosphor layer is impregnated with a sol-gel (e.g., a sol-gel of TEOS or MTMS) or liquid glass (e.g., sodium silicate or potassium silicate), also known as water glass, which saturates the porous structure. The structure is then heated to cure the inorganic glass binder, leaving a robust glass binder that resists yellowing, among other desirable properties.
Abstract:
A method according to embodiments of the invention includes providing a wafer comprising a semiconductor structure grown on a growth substrate. The semiconductor structure includes a light emitting layer disposed between an n-type region and a p-type region. The wafer includes trenches defining individual semiconductor devices. The trenches extend through an entire thickness of the semiconductor structure to reveal the growth substrate. The method further includes forming a thick conductive layer on the semiconductor structure. The thick conductive layer is configured to support the semiconductor structure when the growth substrate is removed. The method further includes removing the growth substrate.
Abstract:
A ceramic green wavelength conversion element (120) is coated with a red wavelength conversion material (330) and placed above a blue light emitting element (110) such that the ceramic element (120) is attached to the light emitting element (110), thereby providing an efficient thermal coupling from the red and green converters (330, 120) to the light emitting element (110) and its associated heat sink. To protect the red converter coating (330) from the effects of subsequent processes, a sacrificial clear coating (340) is created above the red converter element (330). This clear coating (340) may be provided as a discrete layer of clear material, or it may be produced by allowing the red converters to settle to the bottom of its suspension material, thereby forming a converter-free upper layer that can be subjected to the subsequent fabrication processes.
Abstract:
A structure according to embodiments of the invention includes a plurality of LEDs attached to a mount. A wavelength converting layer is disposed over the LEDs. A transparent layer is disposed over the wavelength converting layer. Reflective material is disposed between neighboring LEDs.
Abstract:
A structure according to embodiments of the invention includes a plurality of LEDs attached to a mount. A wavelength converting layer is disposed over the LEDs. A transparent layer is disposed over the wavelength converting layer. Reflective material is disposed between neighboring LEDs.
Abstract:
A ceramic green wavelength conversion element (120) is coated with a red wavelength conversion material (330) and placed above a blue light emitting element (110) such that the ceramic element (120) is attached to the light emitting element (110), thereby providing an efficient thermal coupling from the red and green converters (330, 120) to the light emitting element (110) and its associated heat sink. To protect the red converter coating (330) from the effects of subsequent processes, a sacrificial clear coating (340) is created above the red converter element (330). This clear coating (340) may be provided as a discrete layer of clear material, or it may be produced by allowing the red converters to settle to the bottom of its suspension material, thereby forming a converter-free upper layer that can be subjected to the subsequent fabrication processes.
Abstract:
A multi-stage lamination process is used to laminate a wavelength conversion film (220) to a transparent substrate (230), and subsequently to a light emitting element (110). The wavelength conversion film (220) may be an uncured phosphor-embedded silicone polymer, and the lamination process includes heating the polymer so that it adheres to the transparent substrate (230), but is not fully cured. The phosphor-laminated transparent substrate (230) is sliced/diced and the wavelength conversion film (220) of each diced substrate is placed upon each light emitting element (110). The semi-cured wavelength conversion film (220) is then laminated to the light emitting element (110) via heating, consequently curing the phosphor film. Throughout the process, no glue is used, and the optical losses associated with glue material are not introduced.
Abstract:
A lighting structure according to embodiments of the invention includes a semiconductor light emitting device and a flat wavelength converting element attached to the semiconductor light emitting device. The flat wavelength converting element includes a wavelength converting layer for absorbing light emitted by the semiconductor light emitting device and emitting light of a different wavelength. The flat wavelength converting element further includes a transparent layer. The wavelength converting layer is formed on the transparent layer.
Abstract:
Embodiments of the invention include a semiconductor structure including a light emitting layer sandwiched between an n-type region and a p-type region. A growth substrate is attached to the semiconductor structure. The growth substrate has at least one angled sidewall. A reflective layer is disposed on the angled sidewall. A majority of light extracted from the semiconductor structure and the growth substrate is extracted through a first surface of the growth substrate.
Abstract:
Thick metal pillars are formed upon light emitting dies while the dies are still on their supporting wafer. A molding compound is applied to fill the space between the pillars on each die, and contact pads are formed atop the pillars. The metal pillars provide electrical contact between the contact pads and the electrical contacts of each light emitting die. The metal pillars maybe formed upon an upper metal layer of each die, and this upper metal layer maybe patterned to provide connections to individual elements within the die.