Determination of the dust level on printed circuit boards of electronic equipment by the optical-electronic method

An optoelectronic method for detecting dust deposition on printed circuit boards (PCB)of electronic equipment, which can be used to inform about the critical thresholds of dust accumulation is developed with allowance for the humidity index. The proposed method in combination with the developed mathematical model, functioning diagrams, and light beam motion patterns is used to consider a possible construction and block diagram of the algorithm of control program for the microcontroller of desired implementation of the experimental setup. The principle of operation of the optoelectronic method for detecting dust depositions on printed circuit boards of electronic equipment with allowance for the humidity is following. The light pulses are periodically emitted by two LEDs with a wavelength λ₁= 565 nm (to assess the level of dust deposition) and two LEDs with a wavelength λ₂ = 930 nm (to take into account the level of humidity). The reflected signals from the three plates are taken by the photodiode. The first and second plates placed in a sealed enclosure have an artificially deposited maximum level of dust (humidity 10 and 90%, respectively). The third plate is a control. The third platinum is the control plate. The plates and PCB are made of the same materials. The level of deposited dust (mass concentration per unit area) which triggers the leakage currents between the conductors of the printed circuit board is determined experimentally and depends on the minimum distance between the printed conductors, through which the maximum current flows in a given electronic equipment and on the thickness of the dust layer deposited on the conductors at the maximum permissible humidity specified for the equipment.

1. Astafyev А. V Environment and Reliability of Radio Equipment. — Moscow: Energiya, 1965. — 359 p. [in Russian].

2. Reference Designer REE: General Design Principles / R. G. Varlamov (ed.). — Moscow: Sov. Radio, 1980. — 480 p. [in Russian].

3. Bilibin К. I., Vlasov A. I., Zhuravleva L. V, et al. Design and technological design of electronic equipment. — Moscow: Izd. MGTU im. N. Ё. Baumana, 2002. — 528 p. [in Russian].

4. Handbook of electrical materials / Yu. V Koritsky et al. (eds.) — Moscow: Energoatomizdat, 1986. — 368 p. [in Russian].

5. Semenov V V, Astsaturov Yu. G., Khanzhonkov Yu. B. A device for detecting dust deposits on printed circuit boards of electronic equipment /11th International scientific and practical conf. “Research, Development and Application of High Technologies in Industry”: coll, of works. — St. Petersburg: Izd. Politekh. Univ., 2011. P 175 - 176 [in Russian].

6. Pat. 2426982 RF, IPC G 01N 21/94. Method of dust detection on electronic hardware PCBS / Semenov V V, Astsaturov Yu. G., Khanzhonkov Yu. B., Shchanstny D. A.; applicant and owner South-Russian State University of Economics and Service. — N2009125424/28; appl. 07.02.2009; publ. 08.20.2011. Byull. N 23 [in Russian].

7. Pat. 2503952 RF, IPC G 01 N 21/94. Device to detect dust deposit on printed circuit boards of radio electronics equipment / Semenov V V, Medvedev P A.; applicant and owner South-Russian State University of Economics and Service. — N2012116304/28; appl. 04.23.2012; publ. 10.01.2014. Byull. N 1 [in Russian].

8. Pat. 2503951 RF, IPC G 01 N 21/94. Method to detect dust deposit on printed circuit boards of radio electronics equipment / Semenov V V, Astsaturov Yu. G., Khanzhonkov Yu. B., Medvedev P A.; applicant and owner South-Russian State University of Economics and Service. — N 2012112207/28; appl. 03.29.2012; publ. 01.10.2014. Byull. N 1 [in Russian].

9. Semenov V V, Medvedev P. A. Development of a device for controlling dust deposition in electronic equipment / 4th International Scientific Conference “Modern problems of radio electronics”: coll, of works. — Rostov-on-Don: SRSUES, 2012. P 394 - 397 [in Russian].

10. Semenov Y. Y, Medvedev P. A. Development of a device for controlling dust extraction in electronic equipment / Actual problems of equipment and technology: coll, of works. / South-Russian State University of Economics and Service. — Shakh-tu: SRSUES, 2012. P 84 - 86 [in Russian].

11. Mukhitdinov M., Musaev E. Optical methods and humidity control devices. — Moscow: Energoatomizdat, 1986. — 96 p. [in Russian].

12. Mukhitdinov M., Musaev E. Light-emitting diodes and their application. — Moscow: Radio i svyaz, 1988. — 80 p. [in Russian].

13. Zelenyuk I. Continuous Evaluation of the Reliability of Electronic Nodes / Elektronika: Nauka. Tekhnol. Biznes. 2004. N 5. P 40 - 42 [in Russian].