Chemical sensor matrix

• US 4,596,697 A
• Filed: 09/04/1984
• Issued: 06/24/1986
• Est. Priority Date: 09/04/1984
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Ballato, Arthur
• Primary Examiner(s): Bashore, S. Leon
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/646,536
• Time in Patent Office: 658 Days
• Field of Search: 422/61, 422/68, 422/69, 422/88, 422/90, 422/98, 73/26, 73/61 R, 73/579, 73/DIG. 4, 324/56
• US Class Current: 422/98
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array

Abstract

A chemical sensor matrix is provided for sensing the presence of chemical agents by chemo-electronic means. The chemical sensor matrix is comprised of a plurality of resonators embedded in a single monolithic piece of piezoelectric crystal. The resonators are arranged in rectangular row and column configuration including m rows and n columns, each of the resonators being separated from its neighboring resonators by distances such that the resonant energies do not overlap. Each of the resonators is coated with a different chemical substance to be sensitive to a chemical agent to be detected so that when the chemical substance reacts with the chemical agent, the frequency f_mn changes. Each of the rows of resonators bears a metallic electrode stripe for that row, and each of said columns of resonators bears a metallic stripe for that column. The electrode row stripes are positioned on the top surface of the crystal, and the electrode column stripes are positioned on the bottom surface of the crystal. The areas of overlap of said row and column stripes are registered with the central portions of the embedded resonators. Two diode arrays are positioned on the periphery of the crystal for addressing the individual row electrode stripes and the individual column electrode stripes so that the desired resonator can be activated by connecting the stripe corresponding to its row address and the stripe corresponding to its column address to suitable active oscillator circuitry and signal processing means. The resonators f_mn can then be interrogated sequentially and frequency change registered.

Claims

1. A chemical sensor matrix for sensing the presence of chemical agents by chemo-electronic means, said chemical sensor matrix comprising a plurality of resonators embedded in a single monolithic piece of piezoelectric quartz crystal, said resonators being arranged in rectangular row and column configuration including m rows and n columns, each of said resonators being separated from its neighboring resonators by distances such that the resonant energies do not overlap, each of said resonators being coated with a different chemical substance to be sensitive to a chemical agent to be detected so that when the chemical agent reacts with the chemical substance so that the frequency f_mn changes, each of said rows bearing a metallic electrode stripe for that row and each of said columns of resonators bearing a metallic electrode stripe for that column, said electrode row stripes being positioned on the top surface of the crystal, said electrode column stripes being positioned on the bottom surface of the crystal, and wherein the areas of overlap of said row and column stripes are registered with the central portions of the embedded resonators, two diode arrays positioned on the periphery of the crystal for addressing the individual row-electrode stripes and the individual column electrode stripes so that the desired resonator can be activated by connecting the stripe corresponding to its row address and the stripe corresponding to its column address to suitable active oscillator circuitry and signal processing means and the resonators (mn) then interrogated sequentially and frequency change registered.

3. A chemical sensor matrix according to claim 1 wherein the resonators have the same frequency.

4. A chemical sensor matrix according to claim 1 wherein the resonators differ in frequency.

2. A chemical sensor matrix for sensing the presence of chemical agents by chemo-electronic means, said chemical sensor matrix comprising a plurality of resonators embedded in a single monolithic piece of piezoelectric quartz crystal, said resonators being arranged in rectangular row and column configuration including m rows and n columns, each of said resonators being separated from its neighboring resonators by distances such that the resonant energies do not overlap, each of said resonators being coated with a different chemical substance to be sensitive to a chemical agent to be detected so that when the chemical agent reacts with the chemical substance the frequency f_mn changes, each of said rows of resonators bearing a metallic electrode stripe for that row and each of said columns of resonators bearing a metallic electrode stripe for that column, said electrode row stripes being positioned on the top surface of the crystal, said electrode column stripes being positioned on the bottom surface of the crystal, and wherein the areas of overlap of said row and column stripes are registered with the central portions of the embedded resonators, two diode arrays positioned on the periphery of the crystal for addressing the individual row electrode stripes and the individual column electrode stripes so that the desired resonator can be activated by connecting the stripe corresponding to its row address and the stripe corresponding to its column address to suitable active oscillator circuitry and signal processing means and the resonators (mn) then interrogated sequentially and frequency change registered and a comparison made with the f_mn starting frequencies stored in a read only memory (ROM) device, determining which chemical agents are present, as well as the amount.