Dynamic pressure sensor, photo acoustic gas detector, microphone, hydrophone and method of their manufacture

A photoacoustical gas detection sensor for detection and/or concentration determination of a particular gas in a surrounding environment, comprising:

• a measurement chamber filled with an amount of said particular gas;
• a radiation source that is spaced from said measurement chamber, with said measurement chamber having a wall area or window that is transparent to radiation of said radiation source that has a wavelength that can be one of absorbed and scattered by said particular gas;
• and
• a pressure sensor to measure absolute dynamic pressure in said measurement chamber, with said pressure sensor being one of inside said measurement chamber and adjacent said measurement chamber and including
• (i) a frame;
• (ii) a reference chamber that is not to be exposed to the radiation of said radiation source;
• (iii) a diaphragm attached to said frame, with said diaphragm including a thin planar structure having an outer edge, a measurement side facing said measurement chamber, and a rear side facing said reference chamber;
• (iv) a first attachment structure interconnecting said frame and a first section of said outer edge of said diaphragm;
• (v) a second attachment structure interconnecting said frame and a second section of said outer edge of said diaphragm;
• (vi) a restriction that interconnects said reference chamber and said measurement chamber such that said reference chamber is in fluid communication with said measurement chamber;
• and
• (vii) a signal-generating element to detect mechanical stress in at least one of said first attachment structure and said second attachment structure,
• wherein at least one of said first attachment structure and said second attachment structure provides a reduced area where mechanical stresses caused by pressure are concentrated, and said signal-generating element is arranged at said reduced area,
• wherein sections of said outer edge of said diaphragm other than said first section and said second section are separated from said frame by slits, with a combination of said slits constituting said restriction, and
• wherein said reference chamber and said measurement chamber constitute a closed system filled with said particular gas.

A method for manufacturing a pressure sensor for measuring absolute dynamic pressure, comprising:

• forming at least two elongate narrow slits completely through a thin first sheet of material such that said slits define a restriction and divide said first sheet of material into
• (i) a frame,
• (ii) a diaphragm attached to said frame and separated from said frame by said at least two slits, with said diaphragm having an outer edge, a measurement side that is to face a surrounding environment, and a rear side,
• (iii) a first attachment structure interconnecting said frame and a first section of said outer edge of said diaphragm, and
• (iv) a second attachment structure interconnecting said frame and a second section of said outer edge of said diaphragm;
• forming a recess in a second sheet of material;
• laminating said first sheet of material to said second sheet of material such that said recess defines a reference chamber that faces said rear side of said diaphragm and is in fluid communication with said restriction, whereby said restriction places said reference chamber and the surrounding environment in fluid communication with one another when said restriction is placed in fluid communication with the surrounding environment;
• and
• providing a signal-generating element to detect mechanical stress in at least one of said first attachment structure and said second attachment structure,
• wherein at least one of said first attachment structure and said second attachment structure provides a reduced area which corresponds to an area of said first sheet of material that transitions from said diaphragm to said frame where mechanical stresses caused by pressure are concentrated, and the provision of said signal-generating element includes arranging said signal-generating element at said reduced area.

A method for manufacturing a photoacoustical gas detection sensor for detection and/or concentration determination of a particular gas in a surrounding environment, comprising:

• forming at least two elongate narrow slits completely through a thin first sheet of material such that said slits define a restriction and divide said first sheet of material into
• (i) a frame,
• (ii) a diaphragm attached to said frame and separated from said frame by said at least two slits, with said diaphragm having an outer edge, a measurement side and a rear side,
• (iii) a first attachment structure interconnecting said frame and a first section of said outer edge of said diaphragm, and
• (iv) a second attachment structure interconnecting said frame and a second section of said outer edge of said diaphragm;
• forming a first recess in a second sheet of material;
• laminating said first sheet of material to said second sheet of material such that said first recess defines a measurement chamber that faces said measurement side of said diaphragm and is in fluid communication with said restriction, with said measurement chamber having a wall area or window;
• forming a second recess in a third sheet of material;
• laminating said third sheet of material to said first sheet of material in an atmosphere of said particular gas such that said second recess defines a reference chamber that faces said rear side of said diaphragm and is in fluid communication with said restriction, whereby said measurement chamber and said reference chamber are in fluid communication with one another via said restriction such that said particular gas is present in each of said reference chamber and said measurement chamber;
• providing a radiation source that is spaced from said measurement chamber, with said radiation source to emit radiation to which said wall area or window of said measurement chamber is transparent, and with said radiation having a wavelength that can be one of absorbed and scattered by said particular gas;
• and
• providing a signal-generating element to detect mechanical stress in at least one of said first attachment structure and said second attachment structure,
• wherein at least one of said first attachment structure and said second attachment structure provides a reduced area where mechanical stresses caused by pressure are concentrated, and the provision of said signal-generating element includes arranging said signal-generating element at said reduced area, and
• wherein a combination of said frame, said reference chamber, said diaphragm, said first attachment structure, said second attachment structure, said restriction and said signal-generating element constitute a pressure sensor to measure absolute dynamic pressure in said measurement chamber.