The present disclosure provides an illumination device. The illumination device includes a cap structure. The cap structure is partially coated with a reflective material operable to reflect light. The illumination device includes one or more lighting-emitting devices disposed within the cap structure. The light-emitting devices may be light-emitting diode (LED) chips. The illumination device also includes a thermal dissipation structure. The thermal dissipation structure is coupled to the cap structure in a first direction. The thermal dissipation structure and the cap structure have a coupling interface. The coupling interface extends in a second direction substantially perpendicular to the first direction. The thermal dissipation structure has a portion that intersects the coupling interface at an angle. The angle is in a range from about 60 degrees to about 90 degrees according to some embodiments.