Illumination Device

What is this patent about?

’396 is related to the field of semiconductor lighting, specifically addressing the limitations of traditional light-emitting diode (LED) designs for general illumination. Conventional LEDs emit light in a highly directional manner, making them unsuitable for applications requiring a more diffuse or multi-directional light source, such as indoor lighting. The patent aims to overcome these limitations by providing a light-emitting element that can distribute light more evenly.

The underlying idea behind ’396 is to create a multi-directional light source by combining an LED chip with a transparent substrate. The LED chip is mounted on the substrate, and a wavelength conversion layer (phosphor) is applied. Crucially, the design allows light to escape not only from the top surface where the LED is located but also from the sides and the opposite face of the transparent substrate, achieving a more dispersed light output.

The claims of ’396 focus on an illumination device comprising a supporting base, a transparent substrate coupled to the supporting base, a plurality of LED structures disposed on the transparent substrate, and a bonding layer disposed between the transparent substrate and each of the plurality of LED structures. The transparent substrate and the supporting base are arranged to form an angle ranged of 30-150 degrees, and wherein the plurality of LED structures emits different color lights.

In practice, the LED chip emits light, some of which is converted to a different wavelength by the phosphor layer. The transparent substrate then acts as a light guide, allowing light to exit from multiple surfaces. The angle between the substrate and the base allows for directional control. This contrasts with prior approaches where light extraction is primarily from a single surface, limiting the achievable illumination pattern.

The use of a transparent substrate, such as sapphire, is key to enabling multi-directional light emission . The partial coverage of the substrate with the wavelength conversion layer is also important, as it allows for a mix of converted and unconverted light, influencing the final color temperature and uniformity. By carefully controlling these parameters, the invention aims to provide a more efficient and versatile light source compared to traditional single-sided LEDs.