技術摘要（英）
A condenser lens includes a top surface, a light-incident surface and a light-emitting surface. The light-emitting surface extends between the top surface and the light-incident surface. An area of the light-incident surface is larger than an area of the top surface, there is a height H between the light-incident surface and the top surface, the light-incident surface has a first width W1, the top surface has a second width W2. The first width W1, the second width W2 and the height H satisfy the following formula: 2＜=W1/W2＜=8/3 and 2/3＜=H/W2＜=2 .