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The influence of facet formation on the life of incandescent lamps
102
World Abstracts on Microelectronics and Reliability
stud} of automatic assembly and inspection of incandescent light bulb filaments in the industry is described. The problem is limited to the visual aspect of the system. Picture-processing and pattern-recognition techniques are employed 11 to preprocess the signal provided by a television camera. 2) to transform and extract the features of the object, 3) to classify the lead wires and support wires, and 4) to specify,' tile coordinates of the locations of the tips of the wires. On the assumption that the locations of the tips in the three-dimensional space can be determined through the analysis and processing of two or more two-dimensional visual picture patterns at different angles, the first phase of this feasibility stud) is confined to processing two-dimensional picture patterns. A complete set of algorithms has been developed, implemented, and tested in the Signal Processing Laboratory, Case Western Reserve University, Cleveland. Ohio. Repeatability and consistency of the system arc investigated by varying some key parametcrs, such as lighting, orientation of the object, and setting of the camera. The experimental results show no error in classification and negligible error in specification of the coordinates of the tips.
The influence of facet formation on the life of incandescent lamps. W. LEMS, H. KINKARTZ and W. LECHNER. Philips Res. Rep. 30, 218 (1975), The influence of facet formation on the lite of an incandescent single-coil ttmgsten filament {130 turns of 36-/,m wire in 8.104 N m 2 argon) was studled. At temperatures above 3000 K the coil wire remains round throughout its lifetime, below 3000 K facets predominantly of ',100} type develop. Below 2700K the life of d.c.-operated coils is determined by the formation of notches and thus by surface migration. Facet formation appears to play a role in this notch formation, as the facet geometry leads to periodic constrictions in the wire diameter. Above 2700 K the life of both a.c.- and d.c.-operated coils is determined by evaporation. The development of facets decreases temperature and thus increases life compared to the situation when with equal initial temperature the coil wire would have remained round. In about 70'!;, of all cases the site of initially highest temperature correlates with thc final highest-temperature spot. Calculation of the breakdown characteristics of bipolar transistors using a two-dimensional model. HANs-MARTIN RI!IN.
Solid State Electronics 19. 145 {1976L Tile location el awllanche-breakdown in the c o m m o n emitter output characteristics of bipolar transistors has been calculated for a circular emitter geometry. A two-dimensional model takes account of the very important voltage drop across the base spreading resistance. The dependence of the breakdown points on the bias voltage and the series resistance at the base terminal can be described by simple formuhls, which agree quite well with experimental resuhs.
Bridge transfer in sealed contacts theory and life expectancy. TAKESHI SASAMOTO. N E C Research & Development. 37/38, 74 (1975). The dimension of the molten metal bridge at rupture ill opening low voltage circuits is decided by the temperature distribution on the bridge, the melting regions in both electrodes and the rupture condition of thc bridge. Bridge transfer due to T h o m s o n eltect and the radius of the bridge at rupture increase as the current in the bridge increases. On the other hand, the decay of the current in the bridge becomes smaller as the inductance in the load circuit becomes larger. The bridge transfer volume of the contacts can be calculated by the product of the sectional area of the bridge and the distance of the m a x i m u m temperature scction from the balancing section of the bridge, where the bridge is divided by the ratio of melting volume of one of tile electrodes to that of the other one. So. the bridge transfer volume varies not only with the matter constants of the contacts but also with the inductance in the load circuit. This theory is confirmed by some experimental results. and the life expectancy of the sealed contacts is theoretically discussed. Measurement of the solderability of thick-film circuits; relationship between solder strength and a solderability test. G. P. PANTANELLI. Solid State Tech. p. 39 (Oct. 1975). Results of solder wetting, as measured by a surface tension apparatus, are correlated to visual appearance of a specimen wetted by solder and to the pull strength on a lead soldered to the specimen. The inlluence of an 85' C/85% relative humidity aging condition on tile bond holding strength of the solder joint is also investigated to evaluate the long term reliability of leads soldered to several thickfilm solder pads by two solder compositions, 62Sn 36Pb 2Ag and 1.0Sn 97.5Pb 1.5Ag.
3. CIRCUIT AND SYSTEMS RELIABILITY, MAINTENANCE AND REDUNDANCY Microwave radio equipment for highly-reliable digital communication system. SEtJmO YOKOYAMA, KYO KINOSH1TA, YO1CI4I TAN, TOSHIHIKO RYU, HIROMI HASHIMOTO and SHINJI ONe. N E C Research & Development, Japan 39. 1 (1975). In this system, both 6-GHz and 1 I-GHz microwave links are used for backbone transmission with a capacity of 43.6 Mbit/sec. The equipment consists of a microwave transmitterreceiver and 8 level PSK modulator-demodulator with data processor, With great emphasis placed on high reliability of digital transmission over microwave, the equipment is designed with a hot standby redundancy and space diversity reception mode, employing hitless switching based on sensing of high bit error rate and of the fault diagnosis. Thus, the system is free from interruptions due to a radio path fading or maintenance operations. And, by employing 8-phase modulation and coherent detection regeneration on each hop, the system can transmit 2 bits per hertz in a frequency bandwidth.
On standby" redundancy with delayed repair. Z, KHALIL and I. BOUGAS. IEEE Trans. Reliab. R-24. (4), 286 (1975). This paper derives a) the Laplace-Stieltjes transform of the timeto-system-failure distribution, and b) the mean time-to-system-failure. The system consists of several elements with one repair facility which remains idle until a queue of failed units is built up.
Graphical analysis of accelerated life test data with a mix of failure modes. WAYNE NELSON. IEEE Trans. Reliab. R 24 (4), 230 (1975). An accelerated test of a product under high stress yields life data that are extrapolated to estimate
Availability of a system subject to irregular short supervision. J. M. KONTOLEON and NADIA KONTOLEON. IEEE Trans. Reliab. R-24. (4), 278 (1975). The availability is analysed for a supervised system which has very,' short and
the life distribution at low stress. When the data contain competing failure modes, the dominant modes under high stress may not dominate under low stress. This has made experimenters doubt the validity of tests yielding such data. This expository paper presents new graphical methods for estimating: 1) a separate relationship between life and stress for each failure mode, 2) the life distribution at low stress when all modes act, and 3) the life distribution that would result if certain modes are eliminated. Data from a temperature-accelerated life test of electrical insulation illustrate the methods.
World Abstracts on Microelectronics and Reliability
stud} of automatic assembly and inspection of incandescent light bulb filaments in the industry is described. The problem is limited to the visual aspect of the system. Picture-processing and pattern-recognition techniques are employed 11 to preprocess the signal provided by a television camera. 2) to transform and extract the features of the object, 3) to classify the lead wires and support wires, and 4) to specify,' tile coordinates of the locations of the tips of the wires. On the assumption that the locations of the tips in the three-dimensional space can be determined through the analysis and processing of two or more two-dimensional visual picture patterns at different angles, the first phase of this feasibility stud) is confined to processing two-dimensional picture patterns. A complete set of algorithms has been developed, implemented, and tested in the Signal Processing Laboratory, Case Western Reserve University, Cleveland. Ohio. Repeatability and consistency of the system arc investigated by varying some key parametcrs, such as lighting, orientation of the object, and setting of the camera. The experimental results show no error in classification and negligible error in specification of the coordinates of the tips.
The influence of facet formation on the life of incandescent lamps. W. LEMS, H. KINKARTZ and W. LECHNER. Philips Res. Rep. 30, 218 (1975), The influence of facet formation on the lite of an incandescent single-coil ttmgsten filament {130 turns of 36-/,m wire in 8.104 N m 2 argon) was studled. At temperatures above 3000 K the coil wire remains round throughout its lifetime, below 3000 K facets predominantly of ',100} type develop. Below 2700K the life of d.c.-operated coils is determined by the formation of notches and thus by surface migration. Facet formation appears to play a role in this notch formation, as the facet geometry leads to periodic constrictions in the wire diameter. Above 2700 K the life of both a.c.- and d.c.-operated coils is determined by evaporation. The development of facets decreases temperature and thus increases life compared to the situation when with equal initial temperature the coil wire would have remained round. In about 70'!;, of all cases the site of initially highest temperature correlates with thc final highest-temperature spot. Calculation of the breakdown characteristics of bipolar transistors using a two-dimensional model. HANs-MARTIN RI!IN.
Solid State Electronics 19. 145 {1976L Tile location el awllanche-breakdown in the c o m m o n emitter output characteristics of bipolar transistors has been calculated for a circular emitter geometry. A two-dimensional model takes account of the very important voltage drop across the base spreading resistance. The dependence of the breakdown points on the bias voltage and the series resistance at the base terminal can be described by simple formuhls, which agree quite well with experimental resuhs.
Bridge transfer in sealed contacts theory and life expectancy. TAKESHI SASAMOTO. N E C Research & Development. 37/38, 74 (1975). The dimension of the molten metal bridge at rupture ill opening low voltage circuits is decided by the temperature distribution on the bridge, the melting regions in both electrodes and the rupture condition of thc bridge. Bridge transfer due to T h o m s o n eltect and the radius of the bridge at rupture increase as the current in the bridge increases. On the other hand, the decay of the current in the bridge becomes smaller as the inductance in the load circuit becomes larger. The bridge transfer volume of the contacts can be calculated by the product of the sectional area of the bridge and the distance of the m a x i m u m temperature scction from the balancing section of the bridge, where the bridge is divided by the ratio of melting volume of one of tile electrodes to that of the other one. So. the bridge transfer volume varies not only with the matter constants of the contacts but also with the inductance in the load circuit. This theory is confirmed by some experimental results. and the life expectancy of the sealed contacts is theoretically discussed. Measurement of the solderability of thick-film circuits; relationship between solder strength and a solderability test. G. P. PANTANELLI. Solid State Tech. p. 39 (Oct. 1975). Results of solder wetting, as measured by a surface tension apparatus, are correlated to visual appearance of a specimen wetted by solder and to the pull strength on a lead soldered to the specimen. The inlluence of an 85' C/85% relative humidity aging condition on tile bond holding strength of the solder joint is also investigated to evaluate the long term reliability of leads soldered to several thickfilm solder pads by two solder compositions, 62Sn 36Pb 2Ag and 1.0Sn 97.5Pb 1.5Ag.
3. CIRCUIT AND SYSTEMS RELIABILITY, MAINTENANCE AND REDUNDANCY Microwave radio equipment for highly-reliable digital communication system. SEtJmO YOKOYAMA, KYO KINOSH1TA, YO1CI4I TAN, TOSHIHIKO RYU, HIROMI HASHIMOTO and SHINJI ONe. N E C Research & Development, Japan 39. 1 (1975). In this system, both 6-GHz and 1 I-GHz microwave links are used for backbone transmission with a capacity of 43.6 Mbit/sec. The equipment consists of a microwave transmitterreceiver and 8 level PSK modulator-demodulator with data processor, With great emphasis placed on high reliability of digital transmission over microwave, the equipment is designed with a hot standby redundancy and space diversity reception mode, employing hitless switching based on sensing of high bit error rate and of the fault diagnosis. Thus, the system is free from interruptions due to a radio path fading or maintenance operations. And, by employing 8-phase modulation and coherent detection regeneration on each hop, the system can transmit 2 bits per hertz in a frequency bandwidth.
On standby" redundancy with delayed repair. Z, KHALIL and I. BOUGAS. IEEE Trans. Reliab. R-24. (4), 286 (1975). This paper derives a) the Laplace-Stieltjes transform of the timeto-system-failure distribution, and b) the mean time-to-system-failure. The system consists of several elements with one repair facility which remains idle until a queue of failed units is built up.
Graphical analysis of accelerated life test data with a mix of failure modes. WAYNE NELSON. IEEE Trans. Reliab. R 24 (4), 230 (1975). An accelerated test of a product under high stress yields life data that are extrapolated to estimate
Availability of a system subject to irregular short supervision. J. M. KONTOLEON and NADIA KONTOLEON. IEEE Trans. Reliab. R-24. (4), 278 (1975). The availability is analysed for a supervised system which has very,' short and
the life distribution at low stress. When the data contain competing failure modes, the dominant modes under high stress may not dominate under low stress. This has made experimenters doubt the validity of tests yielding such data. This expository paper presents new graphical methods for estimating: 1) a separate relationship between life and stress for each failure mode, 2) the life distribution at low stress when all modes act, and 3) the life distribution that would result if certain modes are eliminated. Data from a temperature-accelerated life test of electrical insulation illustrate the methods.