Light emitting devices with optical elements and bonding layers

A device comprising:

• a light emitting diode (LED) die comprising a top surface and semiconductor layers including an active region, the LED die having a first coefficient of thermal expansion;
• and
• a discrete and premade transparent optical element comprising a substantially flat bottom surface, the transparent optical element having a second coefficient of thermal expansion approximately equal to the first coefficient of thermal expansion;
• and
• a bonding layer disposed between the top surface of the LED die and the bottom surface of the transparent optical element.

A device comprising:

• a light emitting diode (LED) die comprising a top surface and semiconductor layers including an active region, the LED die having a top layer with a refractive index nLED;
• and
• a discrete and premade transparent optical element comprising a substantially flat bottom surface bonded to a top surface of the LED die, the transparent optical element having a refractive index nlens, where nLED≤lens;
• and
• a bonding layer disposed between the top surface of the LED die and the bottom surface of the transparent optical element.