Optical lens, lens array, and lighting apparatus

A lighting apparatus comprising:

• a light emitting diode (LED) light source disposed on a substrate;
• and
• an optical lens which is to be disposed on an optical axis of the LED light source, and diffuses light from the LED light source toward an illumination target at a location away from the optical axis, the optical lens including:
• a first lens surface having a concave shape which defines a space for housing the LED light source;
• a second lens surface formed in a convex shape curving outward at a position opposite the first lens surface;
• and
• a third lens surface formed continuously from a rear edge portion of the second lens surface, the rear edge portion being on a side opposite an illumination target side, wherein:
• the first lens surface includes a first light-entering surface through which a portion of the light from the LED light source enters, and a second light-entering surface through which another portion of the light from the LED light source enters,
• the second lens surface is a light-exiting surface which refracts at least a portion of the light which has entered the optical lens through the first light-entering surface, in a direction with a predetermined tilt relative to the optical axis, thereby causing the portion of the light to travel to the illumination target,
• the third lens surface is a total reflection surface which totally reflects, to the substrate, at least a portion of the light which has entered the optical lens through the second light-entering surface, and
• an angle between the third lens surface and a principal surface of the substrate on a virtual plane which includes the optical axis is smaller than an angle between the second light-entering surface and the principal surface of the substrate on the virtual plane, at any rotated position, when the virtual plane is rotated about the optical axis to cut the third lens surface.