Automatic alarm for fluorescent blinking

Alarming mechanism, sounding and/or flashing, which signals fluorescent lamp malfunctioning as visibly manifested by flickering. The alarming mechanism according to this invention electrically engages the starter mechanism of a fluorescent lamp and is responsive to current change associated with abnormal flickering. Timely corrective action which is prompted by the alarm may avoid or mitigate one or more deleterious effects of such malfunctioning, such as energy waste, lamp damage, fire hazard and electronic interference. For many embodiments the alarming mechanism and the starter mechanism are advantageously coupled as a single structural unit.

BACKGROUND OF THE INVENTION 
The present invention relates to illuminative apparatus, more particularly 
to illuminative apparatus of the type wherein starting means is employed 
for preheating the electrodes of a fluorescent lamp. 
Conventional fluorescent lamps are electric discharge lamps in which gas 
ionizes and produces radiation which activates fluorescent material inside 
glass tubing. Generally, a fluorescent lamp includes a phosphor-coated 
tubular bulb which has electrodes sealed into each end and which contains 
mercury vapor at low pressure along with an inert starting gas (e.g., 
argon or an argon-neon mixture). The tubular bulb has been practiced in a 
variety of shapes but is usually of straight, U-shaped or circular 
configuration. When the proper voltage is applied across the ends of the 
tubular bulb, an arc is produced by current flowing between the electrodes 
through the fill gas. The ultraviolet energy from the arc excites the 
phosphor coating to emit light; i.e., the phosphor coating transforms some 
of the ultraviolet energy generated by the electric discharge into light. 
The visual sensation of abrupt change in the illumination intensity or 
brightness of a stationary object is known as "flicker." "Cyclic flicker" 
is normally inherent in lighting systems which are supplied with 
alternating current (ac). The light which is emitted from a fluorescent 
lamp or an incandescent lamp which is operated on ac circuitry typically 
executes these cyclic pulsations. The cyclic flicker associated with 
fluorescent lamps is generally of considerably greater magnitude than the 
cyclic flicker associated with incandescent lamps. Nevertherless, in 
normal usage the cyclic flicker associated with either fluorescent lamps 
or incandescent lamps is generally not readily visible. 
Sometimes a fluorescent lamp commences another kind of flicker when it is 
in a malfunctioning mode, often toward the end of its useful life. This 
abnormal flicker is referred to herein as "blinking." Blinking, as 
distinguished from cyclic flicker, is an aberrant phenomenon and 
frequently is visibly appreciable. Blinking generally results from voltage 
fluctuations caused by sudden variations in load, and may be regular or 
irregular. Sometimes blinking regularly recurs in accordance with a 
regular succession of voltage dips; such regular recurrence may be rapid. 
Other times blinking recurs irregularly, in terms of frequency of 
occurrence and/or duration, in accordance with corresponding irregularity 
of voltage dips. 
Blinking not only is energy-inefficient but also forewarns a possible fire 
hazard. The inordinate heating, by excessive voltage, of a component of 
the fluorescent lamp circuitry represents a potentially combustible 
situation. Moreover, fluorescent lighting has been known to interfere with 
proper functioning of digital computers, televisions, radios, remote 
control devices and other forms of electronic apparatus. See, e.g., 
"Interfering Fluorescents," Popular Science, September 1994, page 50. 
Electronic equipment has been observed to be especially vulnerable to such 
interference when the infrared signal emissions from a fluorescent lamp 
are erratic due to voltage fluctuations associated with blinking of the 
lamp. Although circuit-breaking capability has been known to be utilized 
in connection with fluorescent illumination, in conventional practice the 
actual breaking of the circuit may not be effectuated in timely enough 
fashion to have avoided significant deleterious effects of malfunctioning 
associated with blinking. 
A blinking light may be inconspicuously located. Even when a blinking light 
is noticeable, its impact upon an observer can vary. The degrees of 
perceptibility and objectionability of observed fluorescent blinking 
correspond to the change in light output in terms of frequency and 
magnitude, and are affected by several factors such as lamp size, lamp 
type, illumination level, voltage dip rate of change, voltage dip 
duration, surrounding brightness and the observer's physiology/psychology. 
See, e.g., Davidson, G. E., "Flicker in Lighting Systems (Effect of Sudden 
Voltage Dips Studied)," Ontario Hydro Research News, October 1952, vol. 4, 
no. 4, pages 9-11. 
Human nature is such that one may need to be externally motivated in order 
to act in a responsible manner with regard to some occurrence or state of 
affairs in one's life. When a blinking fluorescent bulb is noticed, it may 
not, in and of itself, be annoying or bothersome enough to motivate 
someone to replace the bulb or otherwise correct the underlying problem, 
or even to simply terminate operation of the bulb. A person may be 
particularly neglectful when there remain properly functioning fluorescent 
bulbs which that person views as sufficiently compensating for the light 
deficiency or as sufficiently alleviating the disturbance. 
SUMMARY OF THE INVENTION 
In view of the foregoing, it is an object of the present invention to 
provide automatically responsive warning apparatus for alerting people to, 
or heightening people's awareness of, fluorescent lamp malfunctioning 
which is manifested by blinking. 
Another object of this invention is to provide such apparatus which 
immediately warns of such malfunctioning and thereby affords the 
opportunity for remedial action which may avoid or ameliorate one or more 
deleterious consequences of such malfunctioning, such deleterious 
consequences including energy waste, lamp damage, fire hazard and 
electronic interference. 
Another object of this invention is to provide such apparatus which 
immediately warns of malfunctioning and thereby affords, significantly 
prior to automatic ceasing of operation of a fluorescent lamp which has 
circuit-breaking capability associated therewith, such opportunity for 
remedial action. 
Another object of the present invention is to provide such apparatus which 
may be manufactured, installed and implemented in a previously 
manufactured conventional flourescent lamp. 
A further object of this invention is to provide such apparatus which may 
be manufactured and implemented as part of a conventional flourescent 
lamp. 
A further object of the present invention is to provide such apparatus 
which is economical and efficient and lends itself to widespread use in 
association with fluorescent illumination. 
A fluorescent lamp is generally operated on ac in series with a choke or 
ballast which serves to limit current to the electrodes of the bulb. One 
practiced approach to igniting the lamp is to employ a sufficiently high 
voltage whereby the lamp immediately strikes. According to more common 
practice, however, the ignition of the lamp is furthered by thermal 
emission caused by preheating of the electrodes to an appropriate 
temperature. A starter is generally employed for purposes of carrying out 
this preheating. The starter usually includes a glow switch which includes 
an electron tube containing two strips, at least one of which is bimetal, 
which are closed when heated by the glow discharge. 
In normal operation of a typical glow starter, upon application of the 
transformer voltage a glow discharge commences between the poles of the 
starter whereby a heating effect warms the bimetal and causes it to bend 
over into contact with the other pole. This pole-to-pole contact causes a 
"short circuit" current through the ballast which heats up the electrodes. 
This short circuit in the starter causes the glow discharge to cease and, 
consequently, the bimetal to cool down and break contact. Due to the 
sudden interruption of the short circuit current, a voltage surge is 
produced by the ballast and applied over the discharge path in the lamp, 
causing the lamp to ignite; if the lamp does not ignite, the cycle is 
repeated as many times as necessary to bring about ignition of the lamp. 
An easily ionized inert gas is present in the bulb, in addition to mercury, 
to facilitate starting. The ballast serves as a current-limiting starting 
resistor which is used, along with the starter, for igniting the arc in 
the bulb. For ignition to take place, an arc is first struck between the 
electrode of the starter and the adjacent electrode of the bulb. The 
resultant heating and additional ionization from this arc permit the main 
arc to form between the electrodes of the bulb. 
Normally, upon ignition a voltage is maintained across the lamp which is 
approximately half the open voltage and is insufficient to activate the 
starter. When blinking occurs, this is an indication that the starter 
cycle is abnormally being repeatedly initiated. Time and again, the lamp 
is momentarily lit and immediately unlit due to some malfunction. Each 
time the lamp is de-ignited, the starter is reactivated. 
This repetition of starter actuation accompanied by lamp ignition can bring 
about "flickering overload," which carries and forewarns possible 
undesirable consequences. The excessive ac current which is produced by 
the flickering overload generates excessive heat which can eventually 
damage the circuitry or lead to fire; in particular, the ballast is 
susceptible to shorting out or melting when extremely heated due to 
abnormally long duty cycle. Furthermore, energy is wasted and the 
potential for radio frequency interference is heightened. 
The present invention features alarm means which is responsive to current 
change associated with fluorescent blinking and which automatically 
signals upon the occurrence of the fluorescent blinking. Depending upon 
the embodiment, the alarm includes either or both of an auditory alarm 
(e.g., sounds a beeper) and a visual alarm (e.g., flashes a light). 
In accordance with the present invention, the alarm means which 
electrically engages the starter means may be either structurally separate 
from the starter means or structurally coupled with the starter means. 
Thus, for some embodiments of the present invention the alarm means is 
preferably embodied as a physically separate mechanism which is made to 
electrically engage the starter mechanism which is found in a 
conventional, commercially manufactured preheat-starting fluorescent lamp. 
For most embodiments of this invention, however, the alarm means 
preferably is physically coupled with the starter means and thus made an 
integral part of a multi-functional, uni-structural mechanism which is 
designed to substitute for the starter unit which is found in a 
conventional, commercially manufactured preheat-starting fluorescent lamp. 
According to the present invention, physical coupling of the alarm means 
and the starter means can be accomplished by any of various approaches. 
For some such embodiments the alarm mechanism is preferably made to 
structurally unite with the starter unit which is found in the 
commercially manufactured fluorescent lamp; hence, the original starter 
unit is retained, adapted and supplemented. For other such embodiments the 
multi-functional starter mechanism which comprises starter means and alarm 
means is preferably manufactured as a unit which entirely replaces the 
original starter unit; hence, the original starter unit may be discarded. 
For yet other such embodiments an entire fluorescent lamp unit is 
preferably manufactured whereby the multi-functional starter mechanism 
which comprises starter means and alarm means constitutes a subunit which 
is "built into" the fluorescent lamp unit. 
The conventional commercially made starter mechanism is uni-functional or 
bi-functional. Some conventional starter mechanisms have the sole function 
of preheating the electrodes. Other conventional starter mechanisms are 
additionally equipped with a circuit-breaking capability; many 
commercially manufactured starter mechanisms include a built-in 
circuit-breaker which stops the flow of current in the circuit when it is 
abnormally stressed. 
Circuit-breaking means such as circuit-breakers and fuses are well known in 
the art, and the appropriate implementation of such a protective device as 
a current-stopping "safety valve" for a fluorescent lighting application 
is well within the skill of the ordinarily skilled artisan. "Thermal" 
circuit-breakers and "thermal" fuses, for example, act responsively to 
excessive heat generated by high voltages. Accordingly, it is recommended 
practice for many embodiments and applications that the alarm means 
according to the present invention be accompanied by circuit-breaking 
means which may serve as a subsequently actuated back-up in the event that 
the initially actuated alarm means fails to motivate an individual or 
personnel to remedial action. 
The multi-functional, uni-structural starter mechanism in accordance with 
the present invention is a unit which has the function of preheating the 
electrodes and the additional function of alarming responsively to current 
change associated with the occurrence of fluorescent blinking. Most 
embodiments of the present invention preferably further include the 
function of breaking the circuit and thereby ceasing operation of the 
fluorescent lamp at an appropriate time subsequent to commencement of the 
alarming. 
Structurally unitary embodiments of the present invention conveniently and 
efficiently integrate the preheating function and the alarming function 
(and for many preferred embodiments, the circuit-breaking function) into a 
single structural unit which supplants the conventional starter unit. 
Installation in a fluorescent lamp of this invention's alarming circuitry 
as part of such an integrated structural unit should be more efficient and 
cost-effective than installation thereof as a separate structural unit. 
Moreover, this integrated structural configuration advantageously 
facilitates electrical engagement of its starter-related electronics with 
its alarm-related electronics, not only whereby its alarm means is 
responsive to current fluctuations of its starter means, but also whereby 
the powering of its alarm means is supplied through its starter means. 
Other objects, advantages and features of this invention will become 
apparent from the following detailed description of the invention when 
considered in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to FIG. 1, fluorescent lamp 8 has fluorescent bulb 10, 
starter unit 12 and ballast 14. Fluorescent bulb 10 is operated on ac in 
series with starter unit 12 and ballast 14. Starter unit 12 is 
multi-functional in accordance with the present invention. 
Multi-functional starter unit 12 has a starter tube 15 which has fill gas 
24s, left pole 16 (which is made of bimetal) and right pole 18. Left pole 
16 is connected to left fluorescent lead 20 and right pole 18 is connected 
to right fluorescent lead 22. Fluorescent bulb 10 has fill gas 24b, left 
electrode 26, right electrode 28, two left pins 30 and 32 and two right 
pins 34 and 36. 
Upon application of the line voltage a glow discharge through gas 24s 
commences between bimetal left pole 16 and right pole 18 whereby a heating 
effect causes left pole 16 to bend into contact with right pole 18; 
starter relay 17 between left pole 16 and right pole 18 is now closed. The 
ensuing short circuit current through ballast 14 heats up electrodes 26 
and 28. This short circuit in multi-functional starter unit 12 causes the 
glow discharge in starter tube 15 to cease and, consequently, left pole 16 
to cool down and break contact with right pole 18; starter relay 17 
between left pole 16 and right pole 18 is now open. Due to the sudden 
interruption of the short circuit current, a voltage surge is produced by 
ballast 14 and applied over the discharge path through gas 24b in bulb 10, 
causing bulb 10 to ignite. 
Voltage across starter relay 17 varies between two voltage levels. When 
starter relay 17 is closed, the voltage across the relay is or approaches 
zero. When starter relay 17 is open, the voltage across the relay 
generally is, depending on the nature of bulb 10 and ballast 14, at least 
the line voltage (e.g., 110 volts) and can reach or exceed 200 volts. 
With particular reference to either FIG. 2 or FIG. 3, and still with 
reference to FIG. 1, starter unit 12 has commercial starter 38 and starter 
adjunct 40. Commercial starter 38 is the starter mechanism which was found 
in conventional preheat-starting fluorescent lamp 8 as originally 
manufactured and commercially obtained. Adjunct 40 is coupled with 
commercial starter 38 so as to together provide multi-functional, 
uni-structural starter unit 12, which has replaced commercial starter 38. 
Commercial starter 38, for example standard starter number "FS-40" for 40 
watt bulb 10, includes two twist connectors 42 and 44, circuit-breaker 46 
and overload switch 48. Left connector 42 is for connecting left pole 16 
to left fluorescent lead 20; right connector 44 is for connecting right 
pole 18 to right fluorescent lead 22. Overload switch 48, which for many 
such commercial starters 38 includes a red-colored push-button, is 
activated in order to reset commercial starter 20 once circuit-breaker 46 
has been actuated. 
Adjunct 40 is an electronics package having case 50 which contains 
electronic components including high-pitched (e.g., approximately 12 kHz) 
beeper 52, flashing red light-emitting diode (LED) light 54, left alarm 
lead 56, right alarm lead 58 and sleeve 60. Left alarm lead 56 is 
connected to left pole 16; right alarm lead 58 is connected to right pole 
18. Left alarm lead 56 and right alarm lead 58 pass through sleeve 60. 
Coupling of adjunct 40 with commercial starter 38 is accomplished by any of 
multifarious means known to the ordinarily skilled artisan. For example, 
in FIG. 2 case 50 slidably clamps over commercial starter 38. Commercial 
starter 38 has ridges 62, and case 50 has lips 64, for preventing 
upcoupling of adjunct 40 and commercial starter 38. Case 50 may be 
slidably moved a slight distance downward or upward with respect to 
commercial starter 38, as shown by bidirectional arrow d and distance D. 
When case 50 is moved sufficiently upward relative to commercial starter 
38, overload switch 48 is pushed and thereby activated. In FIG. 3, case 50 
is fixedly attached to commercial starter 38; protruding lever 66 
mechanically engages overload switch 48 and is pivotable a slight distance 
downward or upward as shown by bidirectional arrow e and distance E, and 
thus may be pushed upward to activate overload switch 48. 
Still referring to FIG. 1, when fluorescent lamp 8 is properly functioning, 
starter relay 17 remains open while fluorescent bulb 10 is illuminated. 
Now referring to FIG. 4, g.p. diode 68 (e.g., 600 V.) rectifies 
approximately 110 V. ac into direct current (dc). Capacitor 70 (e.g., 50 
mfd/250 V. dc) filters (smooths) the dc pulses, which then pass through 
dropping resistor 72 so that zener diode 74 (e.g., 12 V.) rectifies and 
charges capacitor 76 (e.g., 2,000 mfd/15 V. dc), which holds the 12 V. dc 
charge as long as fluorescent bulb 10 remains lit. Hence, in the absence 
of flickering overload, capacitor 76 remains charged with 12 V., and 
beeper 52 and LED light 54 remain inactivated. 
During improper functioning of fluorescent lamp 8 whereby fluorescent bulb 
10 is blinking, starter relay 17 opens when fluorescent bulb 10 is lit and 
closes when fluorescent bulb 10 is unlit. Often the blinking is 
attributable to a "weakened" condition of fluorescent bulb 10, which fails 
to maintain illumination. As this "on again, off again" action of the 
starting load for left pole 16 and right pole 18 persists, the resultant 
flickering overload escalates and ballast 14 increasingly overworks and 
overheats. 
During blinking, beeper 52 and LED light 54 each actuate intermittently in 
accordance with the blinking. Beeper 52 sounds and LED light 54 flashes in 
virtual concurrence with the state of deillumination of fluorescent bulb 
10; beeper 52 is silent and LED light 54 is unlit in virtual concurrence 
with the state of illumination of fluorescent bulb 10. 
Resistor 78 is utilized for LED light 54. Upon deillumination of 
fluorescent bulb 10, there ceases to be a potential difference across 
starter relay 17, which is closed. There consequently ceases to be a 
potential difference between beeper 52 and resistor 78 (e.g., 5 kilohm), 
whereupon g.p. diode 68 is inactivated, thereby blocking the direct 
current, and g.p. diode 80 (e.g., 600 V.) is activated, thereby allowing 
return path of voltage stored in capacitor 76, resulting in actuation of 
beeper 52 and LED light 54. The direct current charge which has been held 
by capacitor 76 powers operation of beeper 52 and LED light 54. While 
fluorescent bulb 10 remains lit, the alarm circuit remains fully charged 
in anticipation of the eventuality that fluorescent bulb 10 becomes unlit 
and, concomitantly, beeper 52 and LED light 54 actuate. 
When fluorescent bulb 10 reilluminates, the potential difference across 
starter relay 17, now open, is reestablished; g.p. diode 80 is 
inactivated, thereby blocking the direct current (and, hence, ceasing 
return path of voltage stored in capacitor 76), and g.p. diode 68 is 
activated, thereby allowing rectification of ac into dc, resulting in 
deactuation of beeper 52 and LED light 54. The circuit through capacitor 
70, dropping resistor 72, zener diode 74 and capacitor 76, wherein 
capacitor 76 holds the direct current charge, is reperpetuated for as long 
as fluorescent bulb 10 remains lit. 
Even when fluorescent lamp 8 is functioning normally, for some embodiments 
the alarm according to this invention may be momentarily triggered upon 
"turning on" fluorescent lamp 8. Capacitor 76 may hold some direct current 
charge while fluorescent lamp 8 is "off;" whether alarm beeping/flashing 
occurs upon starting fluorescent lamp 8 may relate to the amount of direct 
current charge which remains held by capacitor 76 while fluorescent lamp 8 
is "off," which may depend on the amount of time which has elapsed since 
fluorescent lamp 8 was last "turned off." Such momentary beeping/flashing 
upon starting fluorescent lamp 8 should be nonexistent or negligible for 
most embodiments, and may even be desirable for some applications. If 
desired, the ordinarily skilled artisan is capable of preventing such 
start-up alarming, e.g., via blocking circuitry or time-delay circuitry. 
Other embodiments of this invention will be apparent to those skilled in 
the art from a consideration of this specification or practice of the 
invention disclosed herein. Various omissions, modifications and changes 
to the principles described may be made by one skilled in the art without 
departing from the true scope and spirit of the invention which is 
indicated by the following claims.