US3617903A

US3617903A - Condition responsive high-voltage gate

Info

Publication number: US3617903A
Application number: US863026A
Authority: US
Inventors: Andrew E Trolio; Edward G Busch
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-09-29
Filing date: 1969-09-29
Publication date: 1971-11-02
Anticipated expiration: 1988-11-02

Abstract

Gating circuitry for ultraminiature light sources. Each gate comprises a plurality of input means which are connected to a different high-voltage pulse source and an output means connected to the electrode of an ultraminiature light source. One of the plurality of input means includes a resistor and the remainder of the inputs each includes a diode. The plurality of input means are connected to output means so that the gate energizes the light source upon coincidence of a pulse generated at each of the voltage sources.

Description

nited tntes tent [72] Inventors Andrew E. Trollio 210 Carlton Ave, lBroornall, Pa. 19008; Edward G. Busch, 454 Marlin Road, Newton Square, lPa. 119073 [21] Appl. No. 863,026 [22] Filed Sept. 29, 1969 [45] Patented Nov. 2, 1971 Continuation of application Ser. No. 507,145, Nov. 110, 1965, now abandoned,

[54] CONlDlITlON RESPONSTVE HIGH-VOLTAGE GATE 3 Claims, 8 Drawing Tigs.

[52] ILLS. C1. 328/94, 315/269, 178/15, 307/218 [51] lint. Cl ll-ll03lr 117/74 [50] Field of Search 328/94 {56] References Cited UNITED STATES PATENTS 2,580,771 1/1952 Harper 328/94 2,797,318 6/1957 Oliwa 328/94 3,196,445 7/1965 Trolio.... 346/1 2,970,303 1/1961 Williams 328/94 Primary Examiner- Donald D. Forrer Assistant Examiner-Harold A. Dixon Attorney-Caesar, Rivise, Bernstein & Cohen ABSTRACT: Gating circuitry for ultraminiature light sources. Each gate comprises a plurality of input means which are connected to a different high-voltage pulse source and an output means connected to the electrode of an ultraminiature light source. One of the plurality of input means includes a resistor and the remainder of the inputs each includes a diode. The plurality ofinput means are connected to output means so that the gate energizes the light source upon coincidence ofa pulse generated at each of the voltage sources.

CGNIDTTIIGN MESIPONSWE ll-llliGliil-VGLTAGE GATE This application is a continuation of application Ser. No. 507,145 filed Nov. 10, 1965, now abandoned.

This invention relates generally to high-voltage-driving techniques and more particularly to a gate responsive to a plurality of conditions for driving a high-voltage circuit.

There are many instances where high voltage is necessary to drive or energize an output circuit. One example of a device requiring high voltage is the ultraminiature light source which uses high voltage to break down the gap between a pin electrode and bar electrode in order to produce an are which provides an ultraminiature source of light. An example of such an ultraminiature light source is shown in US. Pat. No. 3,196,445 which issued July 20, 1965 to Andrew E. Trolio. In such an ultraminiature light source, a plurality of pin electrodes are arranged in a rectangular pattern in order to produce by combinatorial energization of selected ones of said electrodes, a numerical or alphanumerical character which can be recorded by light sensitive paper.

Typically, a number of ultraminiature light sources are used together in order to produce a word or large number. That is, since each ultraminiature light source can produce an alphabetical or numerical character, a plurality of these characters are used together to put together a word or long number. In a typical example, 20 pin electrodes in rows of four and columns of five are used in a numeric light source. Thus, if a numerical representation in the millions is desired, it is necessary to use seven of these light sources together. In the past, it has been necessary to use one power amplifier to fire each pin electrode.

Thus, in the example given, it would have been necessary to use one amplifier for each pin electrode in each of the light sources or a total number of 140 (20x7) power amplifiers. Further, the number of amplifiers needed presents a packaging problem due to the size of the amplifiers even with solidstate circuitry. It has been recognized that due to the extremely high speed at which the ultraminiature light source is energized, and the short duration of the energization it would not be necessary to use all of the amplifiers if the light sources were energized sequentially. Thus, instead of 140 amplifiers, the 20 amplifiers used for a first of these light sources could also be used for the six additional light sources as they are sequentially arced. However, in addition to the 20 amplifiers, it is also necessary to provide a gating system which selects only one of the light sources for energization at a time by the amplifiers. In such a sequential system, it is therefore desirable to have coincidence gates which are capable of steering the necessary high voltage to the individual pin electrodes to fire them.

Existing gates, however, have not been able to handle this problem because they are so inefficient or because the gages have not been reliable.

One coincidence gating method that has been used to fire a pin electrode a light source comprises application of half the breakdown voltage to the pin electrode and a similar inverted voltage to the bar electrode. Thus, upon coincidental application of the aforesaid voltages the voltage differential between the bar and pin electrodes is equivalent to the breakdown potential of the ambient air that forms the gap between the electrode and bar. This system, however, is highly erratic and often results in firing of pin electrodes within a light source when not intended. That is, on a moist day, the breakdown potential of the gap is less than on a dry day. Therefore, since half of the breakdown voltage is applied to either the pin or bar electrodes whenever an input is present, the one input alone can overcome the breakdown potential and drive an arc across the gap if the conditions are right. Further, with normal variations in arc-gap dimensions, wear and tear in use, and various other factors, voltage ranges over which the pin may or may not fire, or ionize, overlap. There is also the probability that the gap may be enlarged and the application simultaneously ofa pulse to both the pin and the bar will not fire the pin. This probability is enhanced because the possibility of only one pulse causing an arc prevents using a larger voltage to overcompensate for wear. Another problem with the aforementioned method is that the gap between the electrode and bar is "floating electronically (that is, neither the electrode nor bar is grounded) and, therefore, spurious pickup and radio interference problems are aggravated.

It is, therefore, an object of this invention to provide a new and improved gate which overcomes the aforementioned disadvantages.

It is another object of the invention to provide a new and improved gate for driving a highvoltage circuit in accordance with the simultaneous occurrence of a plurality of conditions.

It is another object of the invention to provide a high voltage gate which is adapted to drive a plurality of high voltage circuits.

Another object of the invention is to provide a new and improved system for sequentially energizing a plurality of high voltage circuits.

Yet another object of the invention is to provide a new and improved high-voltage gate which is inexpensive to manufacture and which is extremely reliable.

The aforementioned as well as other objects are achieved by providing a gate for energizing a circuit requiring high input voltage for operation thereof, said gate comprising a plurality of input means each connected to a different high voltage pulse source and an output means connected to said circuit, one of said plurality of input means including a resistor. the remainder of said plurality including a diode, said plurality of input means each connected to said output means so that said gate energizes said circuit upon coincidence of a pulse generated at each of said voltage sources.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

FIG. l is a schematic diagram of a high-voltage gate embodying the invention;

FIG. 2 is a diagrammatic schematic block diagram of a photographic-recording system embodying the invention;

FIG. 3 is a diagrammatic schematic block diagram of another photographic-recording system embodying the invention;

FIG. 4 is a schematic diagram of a two input gate embodying the invention and the logic block diagram representation thereof;

FIG. 5 is a schematic diagram of a three-input gate embodying the invention and the logic block diagram representation thereof;

FIG. 6 is a diagrammatic elevational view of a face of an ultraminiature light source;

FIG. 7 is a schematic block diagram of a photographic printer embodying the invention;

FIG. 8 is a schematic diagram of a four-input gate having plural parallel outputs and the logic block diagram representation thereof.

Referring now in greater detail to the various figures of the drawings wherein similar reference characters refer to similar parts, a high-voltage gate embodying the present invention is generally shown at 20 in FIG. 1. Gate 20 is generally comprised of a resistor 22, a diode M and associated circuitry. Resistor 22 and diode 2d are connected to each other via junction 26. Additional diodes 2d are also connected to junction 26 where more than two inputs are used. Thus, for N inputs, N-l diodes are used.

The input including resistor 22 of the gate 20 is connected via input lead 30 to the secondary winding 32 of transformer 34 The primary winding 36 of the transformer 34 is connected to the output of a power amplifier (not shown). The input including diode 24 is connected to secondary winding 3% of transformer 40. The primary winding 42 of transformer 40 is connected to the output of a second power amplifier (also not shown.) Transformers 3d and it) are both step-up voltage transformer. Capacitor M which is connected across secondary winding 32 of transformer 34 may be a physical capacitor but is preferably the distributed capacitance across the transformer. Similarly, capacitor 46 which is connected across the secondary winding 38 of transformer 40 may also be a physical capacitor but is preferably the distributed capacitance across the transformer.

The secondary winding 32 and the capacitance 44 are connected to ground as are secondary winding 38 and capacitance 46. Each additional diode 28 that is connected to the basic gate 20 has a similar input circuit (not shown) to that of diode 24.

Connected to the output junction 26 of the gate 20 is a pin electrode 48 of an ultraminiature light source. lt is separated by a gap 50 from a bar electrode-52 which is connected to ground.

in operation, if a voltage pulse is simultaneously applied by power amplifiers to primary winding 36 and 42, the

transformers

34 and 40, respectively, step up the voltage pulse and a high-voltage pulse output is produced at junction 26 of the gate which is transmitted to the pin electrode 48. The output voltage produced at both of the

secondary windings

32 and 38 is individually large enough to break down the gap 50 and cause arcing between

electrodes

48 and 52.

Only when a positive pulse is applied to both

transformers

34 and 40 is such arcing produced. That is, the arcing does not occur under any other conditions. If no pulse is provided to

transformers

34 or 40, there is no change of voltage at junction 26 and thus no voltage differential across the gap 50. If a pulse is applied only to transformer 34, the voltage rises across resistor 22 and forward biases diode 24 thereby converting diode 24 into a conductor. The voltage at junction 26 is thus attenuated by virtue of the fact that capacitance 46 and the inductance of the transformer 40 in parallel form a low-impedence path to ground potential. Thus, the voltage at junction 26 rises only slightly in comparison to the voltage from transformer 34. Thus, very little voltage is applied to pin electrode 48 and the pin is not fired.

If a pulse is applied to transformer 40 alone, the voltage at the output of secondary winding 38 back biases diode 24 thereby causing isolation or an effectively open circuit between the input to the diode 24 and the junction 26 which thereby prevents a rise of voltage across the gap 50 of the light source. Thus, it can be seen that a single pulse along cannot inadvertently fire pin electrode 48.

' However, when voltage pulses are applied to

primary windings

36 and 42 of

transformers

34 and 40 respectively,

diode 24 remains nonconductive because the voltage provided at the secondary winding 38 is enough to hold off the pulse at the output of secondary winding 32. Thus, since diode 24 does not conduct, the winding 38 and capacitance 42 do not provide a. low-impedence path to ground for the pulse from secondary winding 32. Thus, the voltage at junction 26 reaches the breakdown potential of gap and an arc is produced between

electrodes

48 and 52. Thus, it can be seen from the above description that the voltage at the output of transformer 34 actually drives the electrode to are the gap. This means that the input to the input of the gate including resistor 22 is the only input which need be connected to a highpower driver. This factor can effect substantial economies where a large number of gates are required.

As previously mentioned, the

capacitances

44 and 46 of

transformers

34 and 40 are not necessarily capacitors which are placed across the secondary windings of the transformer. It is preferable that the transformer design of transformer 40 be such that the capacitance thereof permits conduction of the pulse from the transformer 34 to ground to prevent output voltage at junction 26 to cause firing of the pin electrodes. It should also be noted that the transformers used at each of the inputs of the gate 20 are not just an added component to add capacitance. The transformers are necessary between the power amplifier source and the input to the gate to couple as well as to step up the voltage from the power amplifier to the breakdown potential. The capacitance across transformer 40 does not in any way affect the pulse that fires the pin electrode 28 because diode 24 is back-biased thereby isolating the capacitance when the electrode is fired. As the gap is arced, the voltage at junction 26 drops very quickly to ground. The power amplifiers, however, are not afi'ected because the transformer 40 is isolated by the diode 24 and transformer 32 is bypassed by the capacitance 24 to ground.

Where additional inputs including diodes 28 to gate 20 are used, the pin electrode cannot be fired unless each input is coincidentally pulsed. Any combination of input pulses less than the number of inputs to the gate 20 fail to produce an output voltage adequate to fire the pin electrode 48. When a single voltage pulse is applied to resistor 22, the

diodes

24 and 28 are forward biased and provide a parallel low-impedence path to ground through the secondary windings and capacitances of the transformers associated therewith. lf voltage pulses are applied to one or each of

diodes

24 and 28, the back-biased diodes isolate the output junction 26 from the input pulses thereby preventing the pin 48 from firing. Finally if an input pulse is applied to resistor 22 and to at least one of

diodes

24 and 28 but not to each of them, the diode which has not been pulsed is forward biased and provides a low-impedence path to ground thereby attenuating the voltage at junction 26. Thus, unless input pulses are applied simultaneously to all the inputs of the gate 20, the output voltage at junction 26 is not sufficient to cause arcing between

electrodes

48 and 52.

The breakdown voltage of gap 50 is typically in the area of 1,200 volts. Thus, it can be seen that very high voltages can be handled by gate 20 especially when compared to the normal low-voltage ranges that are typically handled by solid-stategating circuitry. in addition, the reliability of the gate is extremely good. The probability of a pin electrode firing as a result of only one input pulse is extremely low because only a very small voltage is applied to output junction 26 unless all of the inputs are pulsed. The grounding of the bar electrode 58, also prevents inadvertent firing or prevention of firing due to spurious pulses being picked up. Since only a very small voltage is applied to junction 26 when less than all of the inputs are pulsed, the voltage applied to junction 26 when all of the inputs are pulsed may be substantially larger than the normal breakdown voltage of the gap. In this manner, the danger of not firing as a result of normal wearing or gap and pulse variations is substantially reduced without substantially increasing the probability of inadvertent arcing.

The design of the gate is such that even though high voltages are used to fire the pin electrode 48, low power solid-state devices may be used throughout. The reason is that high voltage is applied to resistor 24 in short duration pulses only. Pulses of microseconds duration are used. Thus, resistor 22 need have only a very low power rating. Further, the voltage pulses applied to the diode inputs of the circuit merely inhibit the forward biasing of the diodes, thus, high-power amplifiers are not necessary to drive the transformers associated with the diode inputs of the circuit.

A system of firing light sources for a recorder embodying the invention is shown diagrammatically in FIG. 2. The gating system shown in FIG. 2 is used to sequentially fire a plurality of ultraminiature

light sources

54, 56, 58...60. Each light source has twenty pin electrodes 48 as shown diagrammatically in FIG. 6. The mounting 62 for the ultraminiature light source is composed primarily of an insulating material and includes a dielectric material which is placed between the pin electrodes 48 and bars 52. When a pulse is applied to a pin electrode 48 the voltage level of which is in excess of the critical potential necessary to cause a breakdown in the air at the area of the exposed tips of the electrodes, an electrical arc is created between the pin electrode 48 and the electrode bar 52 which, as previously seen, is maintained at substantially ground potential. The are occurs only at the exposed tip of the electrode because the dielectric layers of insulator mounting 62 have a dielectric strength in excess of the ambient air which does not permit an electric breakdown therethrough at the potential which is used to breakdown the air. The electrical discharge between the electrodes 66 and 62 is therefor substantially parallel to the front edge 66 of the ultraminiature light source.

The ultraminiature light source shown in H6. 6 is adapted to display numerical figures only. That is, only 20-pin electrodes are used in the light source shown in MG. 6. Where alphabetic characters are also required, 25-pin electrodes are used. Thus, if the numeral 2 is produced by the light source oflFlG. 6, pins numbered ll, 2, 6, l, 6,112, ll, i6, 6, l3, l7, l6, l6 and 26 are fired simultaneously thereby producing the form of the numeral 2.

in the system of lFlG. 2, seven light sources 66, 56, 56.66 are used. The forth through sixth of these light sources are not illustrated in order to clarify the figure. Also not illustrated for the purpose of clarity, is the photosensitive paper of film which passes closely adjacent the front edges of the light sources 66 through 66 and which records the numbers produced by the light sources.

A plurality of gates are connected to the input of the pin electrodes 66 of the light sources 66, 56, 66.66. 20 gates 66 are connected to the pin electrodes 66 of light source 56. The gates used throughout MG. 2 are illustrated as semicircles with dots therein. As shown in lFlG. 66, each gate having two inputs and an output is equivalent to the gate shown in H6. 66. which has a first input including resistor 22 and a diode 26 included in the second input which are secured together at output junction 26.

The 20 gates 66-ll through 66-26 are each connected to the corresponding pin electrode of the light source 6'6, however, in order to clarify the diagram of lFlG. 2, only two gates 66-1 and 66-26 which are connected to pin electrodes 66 in positions l and 26 respectively of the light source are shown. Similarly, there are 20 gates 66-l through 66-26 which are connected to the corresponding pin electrodes of light source 56, but only gates 66-1. and 66-26 are shown which are connected to the pin electrodes 66 in positions l and 26 respectively of light source 56. 20 gates 76 are connected to the corresponding pin electrodes of light source 56, however, only gates 76-6 and 76-26 which are connected to pin electrodes 66 in positions )1 and 26 respectively of the light source 56 are shown. Finally, 20 gates 72 are connected to the corresponding pin electrodes of light source 66, however, only the gates 72-l and 72-26 which are connected to pin electrodes 66 in locations l and 26 thereof are shown. There are also twenty gates provided for each of the fourth through sixth light source which are also not shown for the purpose of clarity.

A stream of characters are supplied by a character source 76 to the various light sources. Source 76 provides a parallel J output on output lines 76-ll through 76-26 of 20 pulses in a combinatorial binary or on-off code in order to produce the form of the character in a selected light source.

Thus, the twenty output leads 76 are fed the combinatorial signals in parallel. if a numeral 2 is desired on one of the light sources, the following lines 76 of the source would be energized: 76-l, 76-2, 76-3, 76-6, 76-6, 76-312, 76-111, 76-16, 76-6, 76-l2l, 76-27, 76-163, 76-6 and 76-26. The remaining lines, of course, would not be energized.

Character source 76 includes an oscillator and 20 gates which are enabled at predetermined intervals by the oscillator. The character information inputs are applied to the gates which transmit the information to output lines 76-11 through 76-26 output pulses.

Each of the lines 76 from the character source 76 is connected to a power amplifier 76. Twenty power amplifiers 76-11 through 76-26 are provided and they are each connected in turn to transformer 66-l through 66-26, respectively. There are also 20 transformers 66-1 through 66-26. Only two of the output lines 76-ll and 76-26, two of the amplifiers 76-l and 76-26, and two of the transformers 66-i and 66-26 have been shown in order to clarify the diagram.

Transformers 66-l through 66-26 are each connected to the corresponding gates of each of the

light sources

56, 56,

66.66. That is, transformer 66-6 is connected to gates 66-ll, 66-11, 76-ll...72-l. Similarly, transformer 66-26 is connected to the inputs of gates 66-26, 66-26, 76-26...72-26. A column selector 62 is provided having seven output lines 66-11 through 66-7. The column selector is adapted to sequentially energize the output lines and is comprised of a seven-stage ring counter having an output line talten from each stage. interposed between the output lines of the counter and the output lines lid-ll through 66-7 are seven gates. An oscillator is connected to each of the gates to provide pulse outputs sequentially on lines 66-7. through 66-7. One stage of the counter is energized at a time. The stage which is energized enables the associated one of the gates of the column selector to pass a pulse from the oscillator. After a pulse is generated by one of the gates, timing pulses applied via line 66 from the character source to the column selector shift the counter so that the next stage of the counter is energized. After each stage has been energized in sequence, the first stage is again energ zed and the process is repeated. The output lines 66-2 through. 66-7 are connected to seven amplifiers 66-ll through 66-7. Amplifiers 661i through 66-7 are energized by the pulse on the associated output line 66 from the column selector 62. The amplifiers 66 are connected to the seven transformers 66 which are numbered 661i through 66-7.

Transformer 66-2 is connected to each of the gates 66-11 through 66-26. Transformer 66-2 is connected to each of gates 66-ll through 66-26. and similarly transformers 66-3 through 66-7 are connected to the gates associated with light sources 66 though 66 respectively.

Transformers 66-l through 66-26 are each analogous to transformer 66 in H6. l in that they are connected to the input including diode 26 of the gate. Transformers 66-l through 66-7 are analogous to transformer 36 in that they are connected to the input including resistor 22 of the gate. The reason for connecting the transformers in this manner is that the power used to fire the pin electrodes is derived from the power amplifier connected to transformer Thus, since only seven transformers are used, it is more economical to provide only seven high-power amplifiers to drive the transformers 661i through 66-7 than to provide 20 high-power amplifiers to drive transformers 66-1 through 66-26.

In operation, character source 76 supplies via amplifiers '76- 11 through 76-26 a combinatorial parallel signal to the various groups of gates 66, 66, 76 and 72. The column selector simultaneously selects one of the groups of gates 66, 66, 76 or 72 in accordance with the state of the counter within column selector 62. Thus, if output line 66-11 is energized, the amplifier 66 provides a pulse to transformer 66-li which provides an input pulse to gates 66-ll through 66-26. Thus, if the combinatorial code for the number 2 is supplied via lines 76 of the character source 76, gates 66-i 66-2, 66-3, 66-6, 66-6, 66-l2, 66-i ll, 66- 116, 66-6, 66-23, 66-117, 66-i6, 66-19 and 66-26 produce an output signal on the output lines thereof which fire respectively the corresponding pins of the light source After the first group of signals representing a character have been emitted by character source 76, a pulse is produced on line 96 which shifts the ring counter of column selector 62 and thereby energizes line 66-2 thereof. A second group of signals representing a new character is then emitted by source '76 on lines 76-11 through 76-26 and are fed to transformers 66-11 through 66-26 via amplifiers '7 6-11 through 76-26.

simultaneously, the pulse on line 66-2 is fed via amplifier 66-2 to transformer 66-2 which supplies an input pulse to each of gates 66-11 through 66-26. Thus, gates 66-11 through 66-26 are enabled to pass the combinatorial signal pulses from transformers 66-l through 66-26 to the corresponding pin electrodes 66 of light source 66.

As the characters supplied by source 76 are changed, pulses are fed via line 66 to the column selector thereby sequentially energizing the remaining lines 66-31 through 66-7. in this manner a seven-digit number is produced as each of the seven light sources 6'6 through 66 are sequentially operated.

The number of pin electrodes used in the system of FIG. 2 is 140 (20x7). It is seen that only 20 amplifiers were necessary from the character source and only seven amplifiers from the column selector. Thus, instead of having to use 140 amplifiers to energize the electrodes of the light sources, only 27 amplifiers are necessary. It is, of course, evident that if ten light sources were used only thirty amplifiers would be necessary. The amplifiers are, of course, replaced by inexpensive diodes which are used in each of the gates 66 through 72. Since only seven amplifiers were used for selecting the columns and 20 amplifiers were used from the character source, it is preferable to connect the transformers of the column selector to the resistive inputs of the gates. In this manner, only seven highpower amplifiers are necessary to drive all of the l40-pin electrodes. The 20 amplifiers 78 which are associated with the character source 74 are not required to be high-power amplifiers because they merely inhibit the diodes of the gates from being forward biased.

Still further reductions of power amplifiers may be achieved by using the system shown in FIG. 3. The gates used in FIG. 3 are of the three-input-type and are fired as a result of three selecting conditions. In this manner, instead of using 20 amplifiers to drive the 20-pin electrodes of each of the light sources, only nine amplifiers are necessary. Thus, in FIG. 3 rather than providing the 20 signals for an entire character simultaneously, only a row of signals is provided by a row of character source 92. Thus, the row OF character source 92 has four outputs 94-1 through 94-4 rather then the 20 outputs 76 of character source 74. Referring to FIG. 6, it is seen that the first row of a character light source includes the in electrodes 48 in positions 1, 2, 3 and 4. These pin electrodes are first fired combinatorially. The row of character source 92 then produces on output, lines 94-1 through 94-4 the combinatorial signal for the second row of pin electrodes in positions 5, 6, 7 and 8. The source 92 then generates pulses on lines 94-1 through 94-4 representative of the next row of a character. The output lines 94-1 through 94-4 apply the signals from the row of character source 94 to amplifiers 96-1 through 96-4. Amplifiers 96 in turn produce an output pulse which is fed to transformers 98-1 through 98-4. Seven

light sources

100, 102...104 each having 20-pin electrodes are used in the system of FIG. 3. Twenty gates 106-1 through 106-20 are connected to the pin electrodes 1 through 20 respectively of light source 100. It should be noted that each of the gates shown in FIG. 3 is represented as as semicircle having a dot therein and three inputs and an output. As seen in FIG. A and 5B the symbol is equivalent to a gate having resistor input 22, a diode input 24 and a second diode input 28 which are connected together at junction 26.

Similarly, 20 gates 108-1 through 108-20 and twenty gates 110-1 through 110-20 are connected to the respective pin electrodes of

light sources

102 and 104, respectively. There are also 20 gates associated with each of the four light sources which are not shown. Row selector 112 is preferably comprised of a conventional five-stage ring counter in which a state at a time is energized. The row selector also includes an oscillator and gates which are used to provide output pulses on lines 116-1 through 116-4 from the ring counter stage which is energized. The succeeding stages of the counter are energized by shift pulse form the row of characters 92 provided along line 114 after each row of characters is changed.

Row selector 112 has five output lines 116-1 through 116-5 which are connected to the outputs of the five stages of the ring counter. Five power amplifiers 117-1 through 117-5 amplify the pulses from the row selector 112-1 through 112-5 respectively. The outputs of amplifiers 117-1 through 117-5 are connected to transformers 118-1 through 118-5, respectively. Column selector 120 is similar to column selector 82 and has seven output lines 122-1 through 122-7 which are taken from the various stages of the ring counter and gating circuitry which comprise the selector. The ring counter of the selector is shifted along by pulses fed to the column selector via line 124 after all five of the lines 116 have been pulsed.

Thus, only afier a complete cycle of the row selector 112 is the column selector changed.

The outputs of the columns selector 120 are fed to lines 122-1 through 122-7 which are connected to power amplifiers 126-1 through 126-7, respectively. The amplified outputs are then transmitted to transformers 128-1 through 128-7 which are connected to the output of amplifiers 126-1 through 126-7 respectively.

Transformers 98-1 through 98-4 are connected to the four columns of the pin electrodes 48. Thus, referring to FIG. 6, it can be seen that the leftmost column of pin electrodes are in positions numbered 1, 5, 9, 13 and 17. Therefore, transformer 98-1 is connected to the gates associated with these pin electrodes in each of the light sources through 104. For example, with respect to light source 100, transformer 98-1 is connected to gates 106-1, 106-5, 106-9, 106-13 and 106-17. The transformer 98-1 is also connected to the corresponding gates of the group of gates 108 through Similarly, similarly, transformer 98-2 (not shown) is connected to the gates associated with pin electrodes 2 6, 10, 14 and 18 in light sources 100 through 104. The transformer 98-3 (not shown) is connected to the gates associated with

pin electrodes

3, 7, 11, 15 and 19 of the light sources, and transformer 98-4 is connected to the gates associated with

pin electrodes

4, 8, 12, 16 and 20 respectively.

Transformers 118-1 through 118-5 are each associated with a row of pin electrodes 48 in each of the light sources 100 through 104. Referring again to FIG. 6, it can be seen that pin electrodes in positions numbered 1, 2, 3 and 4 comprise the first row of a light source. Thus, transformer 118-1 is connected to gates 106-1 through 106-4, 108-1 through 108- 4...1l0-1 through -4 which are associated with the pins 1 through 4 of each of the

light sources

100, 102...104. Transformer 118-2 (not shown) is connected to the gates in groups 106, 108 and 110 which are connected to pins 5,6, 7 and 8 of the respective light sources.

Similarly, transformers 118-3 through 118-5 are connected to the gates in groups 106, 108 and 110 which are associated with the next three rows of pins of the seven

light sources

100, 102...104.

The transformers 128-1 through 128-7 which are activated by the column selector are each connected to a different one of the groups of gates 106, 108'through 110. That is, transformer 128-1 is connected to the third input of each of the gates in the group of gates 106, transformer 128-2 is connected to each of the gates 108 in the group of gates 108-1 through 108-20... and transformer 128-7 is connected to each of the gates 110-1 through 110-20.

In addition to the various light sources, amplifiers, gates and transformers which are not shown in FIG. 3 as well as in FIGS. 2 and 7, various conventional control circuits for maintaining timing and synchronization of the elements of the system have not been shown. In this manner, the systems embodying the invention can more clearly be shown and succinctly described.

In operation, a first row of character signals is supplied at outputs 94-1 through 94-4. These signals are amplified by amplifies 96 and transmitted to the inputs of gates 106 through 110 by transformers 98-1 through 98-4 respectively. Assuming that the first row is the row including the pin electrodes in positions 1 through 4, the row selector is at the start of a new cycle, therefore amplifier 117-1 is energized by the pulse on output line 116-1 of row selector 112 and transmits a pulse signal to transformer 118-1 which applies a pulse to each gate associated with pins 1 through 4 of the light sources.

Assuming the column selector is in the start of a new column, the output line 122-1 is pulsed thereby energizing amplifier 124-1 which transmits a pulse to gates 106-1 through 106-20 via transformer 128-1. Thus, transformers 118-1 and 128-1 have both coincidentally applied a voltage pulse to diode gates 106-1 through 106-4. Gates 106-1 through 106-4 are therefore enabled to pass the voltage output from transformers 98-1 through 98-4 to pin electrodes 48 in positions 1 through 4 of light source 100. Thus, if any of these transformers were pulsed, the corresponding pins in the row are firedl These are recorded on light-sensitive paper (not shown) which is placed adjacent the light sources lull through Mid.

During the change of the signals on the lines l d-l1 through f t-dan output signal is applied to the row selector via line lllld thereby shifting the row selector lllil. which applies an output pulse on line lll6-2 which is passed to transformer lift-2. Transformer llllll-Il. pulse gates lllt5-5 through ltllti-ll of gates W6 and corresponding gates of the gates fifth and lllll. Transformer l2hl is pulsed again because column selector 12th has not been shifted. The gates enabled by transformers lid-2 and llZh-ll are the gates lids-5 through llllltt-tl thereby passing the combinatorial pulse outputs from transformers @ll-ll through 9ll-d which fire pin electrodes dtl in positions 5 through ll of light source lltltl. After the second row is fired, the row of character source 92 supplies another combination of pulse signals. As the output on lines Wl-ll through Ml-d change, a pulse is applied via line lllld which shifts the counter in column selector Jill and the next output line l to of the row selector is pulsed. This results in the enabling of gates filth-9 through lilo-l2 and the passing of the pulse signals from transformers fllhl through lidl to the selected pin electrodes in positions it through 112 of light source Mill. The next row of characters transformer llldd is pulsed as a result of the shift pulse on line llld applied to row selector llllll.

The last row of characters which is passed to the light source llllll is passed to pin electrodes l7 through as transformer ll ltd-5 is pulsed by row selector llll2. During each ofthe five first steps, transformer lZli-l has received a pulse via amplifier lZll-ll from the column selector mill which has remained in the same state.

After row selector T22 has completed a cycle by energizing output lines llll6-l through lilo-d consecutively, a shift pulse is transmitted on line TM as the output line lilo-ll is pulsed again. The pulse on line 1124 shifts the counter in column selector T22 so that llZZ-ll is deenergized while line 122-2 is pulsed. Thus, transformer 128-2 is energized thereby applying an enabling pulse only to gates Mill-l through 1108-20. Row selector lllIl has pulsed output line lilo-l and in turn energized transformer lid-l which is connected to gates lldil-l through llhd-d. Thus, the gates lllll-l through ltltl-d are enabled by transformers lllltl-ll and lTzld-Zl to pass the outputs of transformers hh-l through Ellil to fire the selected pin electrodes ll through d of the light source lllill. As the pulses emitted by the row of character source 92 change, the succeeding rows are transmitted to the second through fifth row of pin electrodes of light source 1102.

After a row of a character has been steered to the fifth row of light source 1102;, the row selector llll2 transmits another shift pulse on line 124 which changes the state of the counter of column selector 122 to produce an output pulse on line llZZ-El. The line lZZ-Il continues to be pulsed until each row of the next character has been steered to the light source (not shown) which is associated with transformer lIltl-Zi. The succeeding light sources are each operated as transformers TEE-3 through T26 7 are sequentially pulsed by the column selector l2ll. After the last light source lltld has been operated, the column selector counter starts a new cycle and pulses the output line lZZ-ll thereof. The system is now ready to place a new worlc composed of seven characters into the seven light sources llllll to lltld.

It can be seen that by using both a row of characters and a row selector, the system of FlG. 3 is capable of firing 140 pin electrodes with only 16 power amplifiers.

in the system of FIG. 2., 27 amplifiers are needed to drive the 140 pin electrodes. Thus a saving of eleven power amplitiers has been effected by using the system of FIG. 3. In order to lower the number of power amplifiers used it is nece sary only to provide an additional diode for each electrode. That is, instead of having lldll gates each including a single diode it is necessary to provide M0 gates each having two diodes for inputs. l-lowevcr, diodes are relatively inexpensive compared to power amplifiers and a substantial savings is thus effected.

ill

it can be seen, therefore, that by increasing the number of conditions which it taltes to fire a pin electrode, the number of amplifiers necessary can be reduced. Where only one condition is used to fire a pin, lldtl amplifiers are necessary to fire pin electrodes. However, where two conditions were necessary to fire the electrodes, it was seen in MG. 2 that by adding l l-O inexpensive gates, the number of power amplifiers could be reduced to 27. lily using three conditions to fire a pin, it is seen in lFlG. ll that the number of power amplifiers could be reduced to 16 to fire each of the 140 pin electrodes.

in each case where the conditions were increased, there was a factorization of the number of the pin electrodes and the sum of the factors equals the number of power amplifiers. That is, when increasing the number of conditions to two, the number 140 was factored into the two numbers 7 and 20 which total 27. When increasing the conditions to three, it is seen that the number of pin electrodes 20 in each light source was further factored into 5 and Thus, by using three condition, the 16 amplifiers were determined by adding 3 factors of the number 140 (7, 4 and 5).

There is a point at which the increasing of the number of conditions to tire a pin electrode reaches the point of diminishing returns with respect to the reduction of amplifiers and any resultant saving in cost. in the example shown above, where seven light sources each having 20 pin electrodes are used, increasing the number of conditions necessary to fire a pin to four can be done by factoring one of the factors '7, 5 or 4- which were the factors when three conditions were used. The number 7 which is the largest is a prime number. Thus, it does not have a pair of factors which evenly multiply to the number 7. Therefore, by using the next higher number 8 which has two factors (2 and 4) which total 6 the number of amplifiers could be reduced by 1. Thus using four conditions saves one amplifier. The saving of only one amplifier however, is somewhat off-. set by the increased complexity of the circuitry and the increase in number of diodes that are necessary.

When factors equal to the numbers 5 or less remain, there can be no reduction in the number of amplifiers to fire the same number of pins. That is, the number 5 is a prime number and has no factors. Therefore, it is necessary to increase the number to 6. The factors for the number 6 are 3 and 2 which total 5. Therefore, as many amplifiers are required for four conditions as are required for three conditions. it can, therefore, be seen that for any combination of 5 or under, the rais ing of the number of conditions to fire the pins does not lower the number of amplifiers.

Another advantage arising from the high-voltage gate embodying the invention is the fact that the gates may also drive more than a single high-voltage device at a time. That is, the high-voltage output at junction 26 of the gate shown in FIG. l may be applied in parallel to more than one pin. A gate utilizing this principle is shown in lFlG, ll. GATE llZili shown in FIG. 8A has four inputs. The first input includes resistor U2. The remaining three inputs include diodes 113d, T36 and F.3d respectively. Each of the inputs is connected to the others by output lead Mil. The output of the gate lldll is supplied to three resistors 1142, Md and M6. lEach resistor may be connected to a separate pin electrode. lf a high-voltage input is applied to resistors U2 and diodes lild, T36 and 1138 simultaneously, a highvoltage output is applied to each of the re sistors lldll, lldd and Me which fire three pin electrodes concurrently. The resistors M2, Md, and M6 are required between the output lead l lil and each of the pin electrodes in order to prevent only one pin from firing at a time. That is, if three pins are connected directly to output lead lldtl and each pin has a different potential caused by normal variations from wear, etc., when the pin having the lowest arcing potential fires, there is effectively 0 voltage at the conductor lldll. By providing resistors M2, ldd and lldd, however, the firing of the lowest potential does not lower the voltage at the output lead lldt) before the remaining two pins fire. it is understood, that plural outputs may be used with a gate embodying the invention having any number of inputs.

The logic representation of the gate 130 is shown in FIG. 88. FIG. 7 is a logic block diagram of a system which incorporates these gates.

A photographic-printing system is diagrammatically illustrated in FIG. 7. The printer is comprised of a hollow cylindrical drum 150 which has alphabetic and numeric openings around the circumference thereof. The drum is elongated and has 72 rings or columns which are axially spaced and which each contain the entire alphabet and the numerals through 9. Each of the 72 rings of alpha numeric characters are aligned with each other. Thus, all the characters lying along an axially extending line on the periphery of the drum are of the same type. Thus, for example, all of the As are on the same line across the drum. Each of the characters in the circumference of the drum are formed as openings in the wall of the drum. The drum rotates about its longitudinal axis. Light-sensitive paper 152. is passed under the drum very close to the periphery thereof by means which are not shown. For each complete revolution of the drum 150, the paper is moved one space. The paper is moved in the direction of arrow 154.

Running longitudinally within the drum 150 are 72 threearc light sources 156. The light sources are axially aligned and are adjacent the axially extending line of characters adjacent the paper 152. One light source 156 is associated with each column of alphanumeric characters about the drum 150. Each light source requires only three arcs to completely illuminate the back of a character to sufficiently record the character on the light-sensitive paper 152.

A plurality of groups of three resistors are each connected to a different one of column light source 156. Each group of

resistors

142, 144 and 146 is connected to the output of a gate 130. Seventy-two gates 130 are provided. Gate 130-1 is connected via the group of

resistors

142, 144 and 146 to the first column of alphanumeric characters on the drum. Similarly, gate 130-2 is connected to a light source 156 via another group of resistors associated with and connected behind the second column of alphanumeric characters. Similarly, gates 130-3 through 130-72 are connected to the light sources 156 which are associated with the third through 72nd column of alphanumeric characters.

Thus, if any of the gates 130-1 through 130-72 is enabled by high inputs to each of the four inputs of the gate, the enabled gates fire the three pin electrodes within the associated light sources 156 thereby printing the character on the light-sensitive paper 152. Gates 130-1 through 130-72 are enabled only when four input pulses are coincidentally applied to their inputs.

Connected combinatorially to the inputs of the gates 130 are transformers 158-1 through 158-12.

The gates 130-1 through 130-72 are grouped in fours for simplicity of reference. Thus, reference made to the first group of four gates refers to gates 130-1 through 130-4, the second group of four gates refers to gates 130-5 through 130-8 and similarly the l8th group of gates refers to gates 130-69 through 130-72. The transformers are connected in the following manner to the gates:

l. Transformer 158-1 is connected to each of the first 36 gates 130-1 through 130-36.

2. Transformer 158-2 is connected to each of the first 24 gates 130-1 through 130-24.

3. Transformer 158-3 is connected to the first gate of each of the l8th groups of gates. That is, gates 130-1, 130-5, 130-9, 130-13,l30-17,130-21...130-69.

4 Transformer 158-4 is connected to each of the four gates in the first, fourth, seventh, 10th 13th and 16th group of four gates.

5. Transformer 158-5 is connected to the middle 24 gates 130-25 through 130-48.

6. Transformer 158-6 is connected to each of the four gates in the second, fifth eighth, llth l4th'and 17th group of four gates.

7. Transformer 158-7 is connected to the third gate of each group offour gates (130-3, 130-7, 130-11...).

8. Transformer 158-8 is connected to the last 24 gates 49 through 130-72.

9. Transformer 158-9 is connected to each of the four gates in the third, ninth, 12th 15th and 18th group of four gates.

10 Transformer 158-10 is connected to the second gate of each group of four gates (130-2, 130-6, 130-10...).

11. Transformer 1513-11 is connected to the last 36 gates 130-37 through 130-72.

12. Transformer 1521-12 is connected to the fourth gate of each group of four gates (130-4, 130-8, 130-12...

In this manner, 12 transformers which are connected to the outputs of 12 power amplifiers are sufficient to drive each gate individually by pulsing various combinations of four transformers 158 simultaneously.

As previously mentioned, the twelve transformers 158 are connected to 12 power amplifiers which are not shown. The amplifiers are in turn connected to computer circuitry which determines when each of the transformers is to be pulsed. That is, the circuitry which determine which transformers are pulsed include apparatus to sense the rotational disposition of drum 150. This information is converted into signals which correspond to the position of the drum. These signals are compared with those which are to be printed at the various positions along a line. Thus, if an A is to be printed at the first, third and 69th position of a line, when the position of the drum is such that the row of A's are adjacent the light-sensitive paper, the transformers 158-1, 158-2, 158-3 and 1584 are first pulsed simultaneously thereby enabling gate 130-1 to fire the pin electrodes of the light source 156 behind the first column. The firing of the three arcs of light source 156 thereby prints a letter A in the first column. After gate 130-1 has been enabled, transformers 158-1, 158-2, 158-4 and 158-7 are next pulsed simultaneously thereby enabling gate 130-3 which in turn fires the three pin electrodes within the third light source 156 and thereby photographically printing an A in the third column.

After the termination of the enabling signal on gate 130-3, transformers 158-3, 158-8, 158-9 and 158-11 are simultaneously pulsed thereby enabling gate 130-69 which in turn fires the pin electrodes of the light source 156 associated with the column 69 of alphanumeric characters. Thus, an A has been printed in the first, third and 69th positions of the line. The drum is then rotated to the position where B is located between each of light sources 156 and the paper 152. If any B's are to be printed, then the position in which a B should be printed in the line is detected by the computer controlling the energization of transformers 158-1 through 158-12 so that the gate 130 associated with the proper position on the line is enabled. Similarly, the drum continues to rotate and as letters pass through the light sources nd the paper that are to be printed in the remaining positions of the line, the transformers are combinatorially energized to enable the proper gate 130 to fire the pin electrodes in the proper light source.

After one complete revolution of the drum, all of the letters or numerals to be printed in a line will have been printed.

After each complete revolution of the drum 150, the photosensitive paper 152 is moved one line so that the next line can be printed.

It can be seen that by use of the gate 130 at each of the positions 1 through 72 corresponding to the 72 light sources 156, it is possible to reduce the number of power amplifiers necessary to fire the 216 arcs associated with the 72 column light sources 156 from 216 to 12. That is, by using each gate to fire three arcs at a time rather than one, the number of amplifiers necessary is reduced from 216 to 72 (2163). Further, in accordance with the discussion hereinabove, by increasing the number of conditions necessary to enable each gate to operate the light source, the number 72 is factored into smaller components. Thus, the factors 2X3X3X4 were derived. Adding the factors together results in the number l2. Thus, only 12 amplifiers are necessary to combinatorially select each of the 72 gates 130 one at a time. Thus by using four conditions to enable the gates 130, the number of amplifiers is reduced from 72 to 12.

Thus, the gating systems embodying the invention require less power amplifiers to drive a predetermined number of high-voltage devices. The gates used are each responsive to a plurality of conditions for operating the devices. Additionally, where a plurality of devices are to be operated in the same manner, a single gate may be used to tire them concurrently. The resulting need for less amplifiers enables the output devices to be packaged with the gating circuitry and thereby lowering packaging costs as well as reducing the size of the devices.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed as the inventions is:

l. in combination a gate having a plurality of input means and an output means commonly connected to each of said input means, a plurality of high-voltage pulse sources, each of said pulse sources being connected to a different one of said input means via a transformer, one of said plurality of input means including a resistor, the remainder of said plurality of input means each including a diode, said output means of said gate being connected to a pin electrode for use in printing a character, said gate adapted to energize said pin electrode only upon simultaneous application of pulses to all of said input means.

2. The combination of claim ll wherein said pin electrode is provided in combination with a bar electrode to form a light source adapted to provide light for use in printing a character on adjacent light-sensitive paper, said gate adapted to tire said pin upon energization of said electrode.

3. A plurality of gates of r use in a recorder having a plurality of ultraminiature are lamps each including electrodes requiring high-input voltage for operation thereof, said electrodes being provided in a pattern, each of said gates comprising a plurality of input means each connected to a different high-voltage pulse source and an output means commonly connected to said input means and directly connected to a different one of said electrodes, one of said plurality of input means including a resistor, the remainder of said plurality of input means including a diode, said plurality of input means being connected to said output means so that each gate energizes one of said electrodes upon coincidence of a pulse generated at each of said voltage sources connected to said gate.

Patent No.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated November 2, 1971 Andrew E. Trolio and Edward G. Busch It is certified that errors appear in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 59 Column 5, line 65 after the numbers "76-20" insert the word as-.

"in" should be Column 7, line 31 -pin-.

"94" should be Column 7, line 39 "state" should be Column 7, line 58 stage--.

"form" should be Column 7, line 62 from--.

Column 8, line 18 after the word "through" insert the number ll0,.

line 18 omit the word second occurence.

Column 8, "similarly",

Column 8, lines 58 and 59 "amplifies" should be -amplifiers--.

Column 9, line 24 after the word "characters" insert the following:

from source 92 is then passed to pin electrodes 13 to 16 as.

Signed (SEAL) Attest:

EDWARD PLFLMTCHER,JR. Attesting Officer line 33 "122" Column 9, should be Column 9, line 61 "work" should be word.

Column 12, line 51 "nd" should be -and.

Claim 3, line 9 "of r" should be -for-.

Claim 3, line 10 "are" should be --arc--.

and sealed this 25th day of April 1972.

ROBERT GOTTSCHALK Commissioner of Patents

Claims

1. In combination a gate having a plurality of input means and an output means commonly connected to each of said input means, a plurality of high-voltage pulse sources, each of said pulse sources being connected to a different one of said input means via a transformer, one of said plurality of input means including a resistor, the remainder of said plurality of input means each including a diode, said output means of said gate being connected to a pin electrode for use in printing a character, said gate adapted to energize said pin electrode only upon simultaneous application of pulses to all of said input means.

2. The combination of claim 1 wherein said pin electrode is provided in combination with a bar electrode to form a light source adapted to provide light for use in printing a character on adjacent light-sensitive paper, said gate adapted to fire said pin upon energization of said electrode.