Provided is a
light emitting device including a
Fresnel lens and / or a holographic diffuser formed on a surface of a
semiconductor light emitter for improved light extraction, and a method for forming such
light emitting device. Also provided is a
light emitting device including an optical element stamped on a surface for improved light extraction and the
stamping method used to form such device. An optical element formed on the surface of a
semiconductor light emitter reduces reflective loss and loss due to
total internal reflection, thereby improving light extraction efficiency. A
Fresnel lens or a holographic diffuser may be formed on a surface by wet chemical
etching or
dry etching techniques, such as
plasma etching,
reactive ion etching, and chemically-assisted
ion beam
etching, optionally in conjunction with a lithographic technique. In addition, a
Fresnel lens or a holographic diffuser may be milled, scribed, or ablated into the surface.
Stamping, an alternative method for forming an optical element, can also be used to form a Fresnel lens or a holographic diffuser on the surface of a
semiconductor light emitter.
Stamping includes pressing a
stamping block against the surface of a
light emitting diode. The
stamping block has a shape and pattern that are the inverse of the desired optical element. Optionally, stamping can be done before, after, or concurrently with
wafer-bonding. Alternatively, a material can be stamped and later bonded to the semiconductor light emitter.