Provided is a light emitting device, which includes a second conductive type semiconductor layer, an active layer, a first conductive type semiconductor layer, and a intermediate refraction layer. The method includes the steps of: receiving at least one of a negative and positive example from one or more other users; and determining a recommendation for a user based on at least one of the negative and positive examples. A solid immersion lens housing is slidably mounted onto said objective lens housing, and a solid immersion lens is mounted onto the SIL housing. A biodegradable composite screw is provided. The clearable sections include a right section and a left section so that the captured images can be used to produce 3D pictures or displays.