Abstract: A crystal oscillator includes an oscillating substrate, a hollow frame, a first electrode, and a second electrode. The oscillating substrate includes a main oscillating region and a thinned region that has a thickness smaller than that of the main oscillating region. The first and second electrodes are disposed on a first surface of the oscillating substrate and a second surface opposite to the first surface, respectively. The hollow frame is disposed on the second surface. The second electrode includes a second electrode portion that has at least one opening in positional correspondence with the thinned region. A method for making the crystal oscillator is also provided herein.

Abstract: A crystal oscillator includes a piezoelectric substrate having a thinned portion with opposite upper and lower surfaces respectively defining upper and lower surface work portions, and at least one side portion having at least one recessed portion with a bottom surface flush with the upper surface of the thinned portion. A top electrode layer has a top work portion disposed on the upper surface work portion, and a top extension extending from the top work portion onto the bottom surface of the recessed portion. A bottom electrode layer has a bottom work portion disposed on the lower surface work portion, and a bottom extension extending from the bottom work portion toward the one end of the thinned portion and then bending upward and inward onto the bottom surface of the recessed portion. A method of making the crystal oscillator is also disclosed.

Abstract: A crystal oscillator includes an oscillating substrate, a hollow frame, a first electrode, and a second electrode. The oscillating substrate includes a main oscillating region and a thinned region that has a thickness smaller than that of the main oscillating region. The first and second electrodes are disposed on a first surface of the oscillating substrate and a second surface opposite to the first surface, respectively. The hollow frame is disposed on the second surface. The second electrode includes a second electrode portion that has at least one opening in positional correspondence with the thinned region. A method for making the crystal oscillator is also provided herein.