Diaphragm and MEMS sensor using same

The present invention provides a diaphragm and a MEMS sensor using the diaphragm. The diaphragm is a rectangular diaphragm, and the diaphragm includes a main body of the diaphragm and fixed parts arranged outside the main body of the diaphragm and located at the four corners of the diaphragm. The four corners of the rectangular diaphragm are depressed parts formed by concave in the direction of the diaphragm main body. The fixed part includes at least two fixed anchor points arranged along the edge of the diaphragm forming the depressed part. The present invention improves the effective sensing area of the diaphragm and the acoustic performance of the MEMS sensor.

FIELD OF THE PRESENT DISCLOSURE

The present invention relates to a diaphragm and a MEMS sensor using the diaphragm, especially to a fixed structure of the diaphragm.

DESCRIPTION OF RELATED ART

With the development of wireless communication, users have higher and higher requirements on the call quality of mobile phones. The microphone is used as the voice pickup device of the mobile phone, and its design directly affects the call quality of the mobile phone.

The microphone in mobile phones is the MEMS microphone. A MEMS sensor related to the present invention includes a basement and a capacitive system composed of a diaphragm and a back plate. The diaphragm and the back plate are opposite and spaced apart. The diaphragm vibrates under the action of sound waves, resulting in a change in the distance between the diaphragm and the back plate. In turn, the capacity of the capacitive system is changed, thereby converting the acoustic signal into an electric signal. However, due to the fixing method of the diaphragm, the entire outer part of the diaphragm is generally attached to the basement and fixed. In this way, the sensing area of the diaphragm is sacrificed, resulting in a lower acoustic performance of the MEMS sensor.

Therefore, it is necessary to provide a new diaphragm and a MEMS sensor using the diaphragm to solve the above technical problems.

SUMMARY OF THE PRESENT INVENTION

The present invention is to provide a diaphragm that increases the area of the effective sensing area.

The present invention provides a diaphragm, including: a diaphragm main body; and a plurality of fixed parts arranged at corners of the diaphragm main body. Corners of the diaphragm are depressed parts formed by concave in a direction of the diaphragm main body. The fixed part includes at least two fixed anchor points arranged along an edge of the diaphragm for forming the depressed part.

Further, the diaphragm includes two fixed anchor points symmetrically arranged at both ends of the edge where the diaphragm forms the depressed part.

Further, a depth of the depressed part of each corner position along a diagonal of the diaphragm does not exceed 10% of a diagonal length of the diaphragm.

Further, a number of the fixed anchor points is greater than two; the fixed anchor point extends from the edge for forming the depressed part along the diaphragm to a straight edge of the diaphragm.

Further, the diaphragm includes an arc corrugated part disposed behind the depressed part.

Further, the corrugated part includes a plurality of concentric arc protruded parts arranged at equal intervals.

The present invention further provides a MEMS sensor, including: a diaphragm as described above; a basement having a cavity for supporting the diaphragm; and a back plate opposite to and spaced from the diaphragm.

Further, the back plate includes a backplane main body and a support part extending from the backplane main body for being fixed on the basement.

Compared with the related art, the present invention provides a diaphragm for the MEMS sensor, and the diaphragm is a rectangular diaphragm. The diaphragm includes a diaphragm main body and fixed parts disposed outside the diaphragm main body and located at four corners of the diaphragm. The four corners of the rectangular diaphragm are depressed parts formed by concave in the direction of the diaphragm main body. The fixed part includes at least two fixed anchor points arranged along the edge of the diaphragm forming the depressed part. The present invention is mainly by setting fixed anchor points outside the diaphragm main body of the diaphragm, and the entire diaphragm is fixed by the fixed anchor points. In order to increase the effective sensing area of diaphragm, so as to achieve the purpose of improving the MEMS sensor's acoustic performance.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

It should be noted that, all directional indications (such as up, down, left, right, front, back, inner, outer, top, bottom . . . ) in the embodiment of the present invention are only used to explain the relative positional relationship between the various components shown in the attached figure), etc., if the specific posture changes, the directional indication also changes accordingly.

It should also be noted that when an element is referred to as being “fixed to” or “disposed on” other element, it can be directly on other element or intervening elements may also be present. When an element is referred to as being “connected” to the other element, it can be directly connected to the other element or intervening elements may also be present.

Please refer toFIGS.1-5, a MEMS sensor100provided by the present invention can be used in electronic equipment. The mems sensor100includes a basement1with a cavity10, a diaphragm2fixed on the basement1, and a back plate3covering the diaphragm2.

The cavity10is set throughout the basement1.

The diaphragm2is a rectangular diaphragm, and the diaphragm2includes a diaphragm main body21and fixed parts22disposed outside the diaphragm main body21and located at four corners of the diaphragm2. The four corners of the rectangular diaphragm are recessed in the direction of the diaphragm main body21to form depressed parts23. The fixed part22includes at least two fixed anchor points220disposed along the edge of the diaphragm2forming the depressed part23. As shown inFIG.4, the number of fixed anchor points220for each corner position in the embodiment may be two. The fixed anchor points220are symmetrically arranged at both ends of the edge of the diaphragm2forming the depressed part23. Of course, the number of the fixed anchor points220may also be greater than two. As shown inFIG.5, the fixed anchor points220of each corner position extend from the edge that forms the depressed part23along the diaphragm2to the straight edge of the rectangular diaphragm. In the embodiment shown inFIG.4, the number of fixed anchor points220of the entire diaphragm2is 6. In other embodiments, the number, size and distribution of fixed anchor points can be adjusted according to actual needs, such as different diaphragm stiffness requirements.

The depressed part23of each corner position along the diagonal of the diaphragm does not exceed 1/10 of the diagonal length of the rectangular diaphragm. The diaphragm2includes an arc corrugated part24arranged behind the depressed part23. The corrugated part24consists of several concentric arc protruded parts240arranged at equal intervals. The fixed anchor point220extends from the edge forming the depressed part23along the diaphragm2to the straight edge of the rectangular diaphragm and does not extend to the corrugated part24.

As shown inFIG.4, if the sensor of the present invention is set as a square with an overall size of 1 mm×1 mm, for example, its edge length x is 1 mm, since the diaphragm of the present invention is fixed by setting the depressed part and the fixed anchor point, the effective sensing area a of the diaphragm can reach 68% of the entire area of the diaphragm. The diaphragms in the prior art as an example, please refer toFIG.6, which is a top view of the basement and the diaphragm in the first prior art sensor. A sensor includes a diaphragm4. The diaphragm4is also a square diaphragm, and the overall sensor edge length is y. The diaphragm4includes a main body41, a number of extension parts42arranged outside the main body41and arranged at four corner positions of the diaphragm, a fixed part43set in the extension part42end part. The sensor is set to an overall size of 1 mm×1 mm, that is, the edge length y is 1 mm, the effective sensing area b of its diaphragm can only reach 45% of the entire diaphragm area. Please refer toFIG.7, which is the top view of the basement and the diaphragm in the second sensor of the prior art. The diaphragm5is a circular diaphragm, the sensor is a square, and the edge length is z. The diaphragm5includes a main body51, a number of extension parts52extending outside the main body51, a fixed part53set in the end part of the extension part52. The sensor is set to an overall size of 1 mm×1 mm, that is, the edge length z of the outer frame is 1 mm, the effective sensing area c of its diaphragm can only reach 44% of the entire area of the diaphragm.

It can be seen from the above that the present invention can utilize the effective sensing area of the diaphragm to the greatest extent, thereby improving the sensitivity of the sensor.

The back plate3is provided with a plurality of through holes30penetrating the back plate3. The back plate3includes a backplane main body31and a support part32that is bent and extended from the backplane main body31and fixed to the basement1. The backplane main body31and the support part32are surrounded by a containment space. The diaphragm2is accommodated in the containment space.

Compared with the related art, the present invention provides a diaphragm for the MEMS sensor, and the diaphragm is a rectangular diaphragm. The diaphragm includes a diaphragm main body and fixed parts disposed outside the diaphragm main body and located at four corners of the diaphragm. The four corners of the rectangular diaphragm are depressed parts formed by concave in the direction of the diaphragm main body. The fixed part includes at least two fixed anchor points arranged along the edge of the diaphragm forming the depressed part. The present invention mainly increases the effective sensing area of the diaphragm by setting fixed anchor points outside the diaphragm main body of the diaphragm, and the entire diaphragm is fixed by the fixed anchor points, thereby achieving the purpose of improving the MEMS sensor's acoustic performance.