LED lighting unit

A LED lighting unit, comprising:

• a support structure;
• an LED chip mounted within the support structure, the LED chip comprising a height of less than 0.6 mm;
• an optical beam shaping arrangement disposed over the support structure and comprising a microstructured layer positioned at a height of less than the square root of a light emitting area of the LED chip above the LED chip, the microstructured layer comprising:
• an optically transparent and thermally stable material having a refractive index;
• and at least one array of micro-elements that extend in a line giving a one-dimensional repetition, each micro-element having one or more sides which meet at a top apex, the one or more sides being straight from their base to the top apex, a distance from the top apex of at least one micro-element to a bottom surface of the LED lighting unit opposite the top apex is less than 1.5 mm;
• and
• a first material between the LED chip and the optical beam shaping arrangement, the first material having a first refractive index, the refractive index of the optically transparent and thermally stable material is between 0.3 and 0.65 greater than the first refractive index, and the optical beam shaping arrangement is:
• in contact with the first material of the first refractive index;
• or bonded to the first material of the first refractive index through an intermediate bonding layer;
• or bonded to the LED chip using a partial bonding layer having bonding portions and portions of the first material of the first refractive index.