Abstract: A frequency-tunable film bulk acoustic resonator and a preparation method therefor are provided. The resonator includes a substrate, an air gap, a sandwiched structure formed by electrodes and piezoelectric layers, and an electrode lead-out layer, wherein the substrate is connected to the sandwiched structure formed by the electrodes and the piezoelectric layers, and a connection face of the substrate and the sandwiched structure formed by the electrodes and the piezoelectric layers is recessed towards inside of the substrate to form the air gap; and the electrode lead-out layer is connected to the sandwiched structure formed by the electrodes and the piezoelectric layers. The sandwiched structure formed by the electrodes and the piezoelectric layers includes a bottom electrode, piezoelectric layers, intermediate electrodes, and a top electrode, wherein the electrodes and the piezoelectric layers are alternately arranged to form the sandwiched structure.

Abstract: A visible light communication emission device with improved response frequency is provided, comprising a substrate, wherein an inductance coil module is provided on the substrate, a LED chip matrix formed by series connection of a plurality of LED chips is provided on the inductance coil module, and the inductance coil module and the LED chip matrix are connected in series, wherein inductance value L of the inductance coil module is configured to be: L=1/(?2C), with C representing capacity in the device provided by LED chips and ? representing frequency, wherein the inductance coil module comprises more than one inductance coil whose composition materials from inside to outside are successively Cr, Al, Cr, Ti, and Ag.

Abstract: A visible light communication emission device with improved response frequency is provided, comprising a substrate, wherein an inductance coil module is provided on the substrate, a LED chip matrix formed by series connection of a plurality of LED chips is provided on the inductance coil module, and the inductance coil module and the LED chip matrix are connected in series, wherein inductance value L of the inductance coil module is configured to be: L=1/(?2C), with C representing capacity in the device provided by LED chips and ? representing frequency, wherein the inductance coil module comprises more than one inductance coil whose composition materials from inside to outside are successively Cr, Al, Cr, Ti, and Ag.