MEMS device and electronics apparatus

1. A MEMS device, comprising:

a substrate;

a MEMS element placed on the substrate;

a cover encapsulating the MEMS element together with the substrate; and

a port for the MEMS element to access outside,

wherein the port is provided with a filter which has mesh holes and includes electrets to prevent particles from entering into the MEMS element, and the electrets are placed on two surfaces of the filter and are charged with opposite charges.

2. The MEMS device according to claim 1 , wherein the MEMS element is one of the following elements: a MEMS microphone element, a MEMS pressure sensor element, a MEMS humidity sensor element, a MEMS gas sensor element, a MEMS chemical sensor element and a MEMS speaker element.

3. The MEMS device according to claim 1 , wherein the electrets of the filter are surface charged electrets.

4. The MEMS device according to claim 1 , wherein the electrets of the filter are bulk charged electrets.

5. The MEMS device according to claim 1 , wherein the filter is a meshed plate or membrane.

6. The MEMS device according to claim 1 , wherein the filter is made of metal plate, the surfaces of the metal plate are covered by polymer, and the polymer is charged with electret charges.

7. The MEMS device according to claim 1 , further comprising a support substrate, wherein the support substrate is attached with the filter to support the filter.

8. The MEMS device according to claim 1 , wherein the port is provided in the substrate or the cover.

9. An electronic apparatus comprising a MEMS device according to claim 1 .

10. An electronic apparatus comprising a MEMS device according to claim 2 .