Led optical lens and illumination device thereof

A light-emitting diode (LED) illumination device comprising at least one optical lens, at least one LED light source and a holder, wherein

• the optical lens having at least one light-source side surface and at least one image side surface is a transparent lens and is mounted in a hole disposed on the holder correspondingly;
• the light-source side surface and the image side surface are designed by mathematical expressions of freeform surfaces;
• the LED light source faces the light-source side surface of the optical lens;
• the holder is disposed with at least one hole that is mounted with an optical lens;
• wherein light emitted from the LED light sources emits into the optical lens through the light-source side surface of the optical lens and out of the image side surface to be projected into a target area;
• by the light-source side surface and the image side surface designed according to mathematical expressions of freeform surfaces, a near rectangular light distribution pattern is generated on the target area and there is a ratio of a length along a long axis to a width along a short axis of the near rectangular light distribution pattern.