US3233110A

US3233110A - Polarized photoelectric switching system

Info

Publication number: US3233110A
Application number: US237670A
Authority: US
Inventors: George T Senseney
Original assignee: WHITE AVIONICS CORP
Current assignee: WHITE AVIONICS CORP
Priority date: 1962-11-14
Filing date: 1962-11-14
Publication date: 1966-02-01
Anticipated expiration: 1983-02-01

Description

Fe 1, 1966 G. T. SENSENEY POLARIZED PHOTOELECTRIC SWITCHING SYSTEM Filed Nov. 14, 1962 FIG INVENTOR. GfO/ifif I JHVSMH United States Patent 3,233,110 POLARIZED PHOTOELECTRIC SWITCHING SYSTEM George T. Senseney, New York, N.Y., assignor to White Avionics Corporation, Plainview, N.Y., a corporation of New York Filed Nov. 14, 1962, Ser. No. 237,670 Claims. (Cl. 250209) The present invention relates to an electrically controlled switching system having no moving parts and an exceptionally high speed of response.

Electrical control of switch action is common. Perhaps the most common instrumentality operating on this principle is the electromagnetic relay, in which electrical energization of a winding causes magnetic attraction of an armature, the movement of the armature actuating mechanical switch contacts. Such devices, although in very widespread use, have certain inherent drawbacks-their time of response is limited because movement of mechanical parts is required, their sensitivity is limited be cause of the mass (inertia) of those mechanical parts, and their longevity is limited because of the wear incident upon mechanical movement and the engagement and separation of current-carrying contacts.

Various types of electronic systems have been devised which avoid the disadvantages inherent in mechanical movement. These electronic systems provide a great decrease in switching time, but in many instances they involve relatively complex circuitry and the use of troubleprone electronic components.

It is the prime object of the present invention to devise a simple system for controlling the switching of external circuits, which system has an exceptionally high speed of response, involves no moving parts, and is exceptionally simple and reliable. The system of the present invention is specially adapted to be sensitive to the polarity of the input signal, actuating the output circuits in a given way when the polarity of the input signal is of a given sense and actuating the output circuits in a different way when the polarity of the input signal is of the opposite sense. It is a further prime object of the present invention to devise such a system in which the controlling parts are incorporated into a sturdy, simple and small assembly.

In accordance with the present invention the instrumentalities which actually carry out the switching operation are light-sensitive elements, and the actuation of those elements is accomplished by controlling the light which impinges upon them. A pair of light-sensitive elements are provided, each preferably controlling a different utilization circuit. The light source is in the form of a glow discharge tube having first and second electrodes and having the characteristic that only one of said electrodes glows at a time depending upon the polarity of the DJC. energization applied to the tube. Each of the light sensitive elements is associated in a light-transmissive sense with a dilfere-nt one of the glow discharge tube electrodes, so that when a given one of those electrodes glows a significant amount of light reaches only that light sensitive element operatively associated therewith. In this way one or the other of the light-sensitive elements is actuated, depending upon the polarity of the electrical signal applied to the glow discharge tube. When, as is preferred, the light-sensitive elements have an inherent latching efiect (when once rendered conductive by the impingement of light thereupon, they will remain conductive for as long as appropriate potential is applied thereto), a commutating capacitor may be associated with those elements, so that when one is rendered conductive the other is rendered non-conductive.

More specifically, a polarized photoelectric assembly 3,233,110 Patented Feb. 1, 1966 is produced which comprises a housing having an aperture in which a glow discharge tube of the type described is mounted. A pair of light-transmissive paths are formed in that housing, each extending from a different electrode of the glow discharge tube to a station (preferably an aperture) where a light sensitive element is mounted. The light transmissive paths are specifically disclosed as being defined by slots formed in the housing and extending from the glow discharge tube aperture to the light-sensitive element stations, the walls and/ or body of the housing being sufiiciently opaque so that light emanating from a given glow discharge tube electrode, when it glows, passes substantially only to the particular light-sensitive element associated therewith. The entire assembly of housing, glow discharge tube and light-sensitive elements comprises a small, sturdy and protected unit. Appropriate electrical connections to the operative elements may readily be made. The resultant system has no moving parts, there is no bounce or chatter, such as characterize mechanical relays, no magnetic fields are developed, as in magnetic relays, which might adversely affect associated circuits, and the operative parts may be encapsulated or otherwise protected so as to be exceptionally resistant to vibrations, shock, high temperature, humidity, corrosive atmospheres and the like.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to the construction of a photoelectric assembly and a photoelectrically controlled switching system, all as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:

FIG. 1 is a top plan view of a preferred embodiment of the present invention;

FIG. 2 is a cross sectional view taken along the line 2-2 of FIG. 11; and

FIG. 3 is a circuit diagram illustrating a preferred man ner in which the assembly of FIGS. 1 and 2 may be used.

The polarized photoelectric assembly of the present invention comprises a housing generally designated 2 of any suitable material, such as electrically insulating plastic. An aperture 4 is formed in the housing 2 and two

slots

6 and 8 extend in opposite directions from the aperture 4 to apertures 10 and 12 respectively. A glow discharge tube '14 is mounted in any appropriate manner in the aperture 4. This tube is provided with electrodes 16 and 18 which extend out from the tube 14 and to which appropriate electrical connections may be made, as described more in detail below. The tube 14 has the characteristic that when appropriate D.C. energizat-ion is applied to the electrodes '16 and 18, only one of those electrodes will glow, depending upon the polarity of that energization. For example, when the tube 14 is in the form of a neon lamp, only that one of the electrodes 16 and 18 which is the cathode will glow. Moreover, with a tube of that type, and when an appropriate potential difference is applied across the electrodes 16 and 18, that electrode which is the cathode will glow virtually instantaneously with the application of appropriate electrical energization thereto. The tube 14 is so positioned within the aperture 4 that each of its electrodes 16 and 18 is operatively optically associated with a different one of the

slots

6 and 8. As here specifically disclosed the electrode 16 is positioned opposite the inner end of the slot 6 and the electrode 18 is positioned opposite the inner end of the slot 8.

Light

sensitive elements

26 and 22 are mounted in any appropriate manner in the apertures 10 and 12 respectively so as to be operatively optically associated with light passing through the

slots

6 and 8 respectively. The light-

sensitive elements

26 and 22, in the form here specifically disclosed, comprise PNPN silicon diodes Zita and 22a respectively encased within transparent housings 29b and 22b and having leads 26c, 20d and 22c, 22d extending therefrom respectively.

In order to prevent any appreciable amount of light emanating from the electrodes 16 and 18, when each of them glows, from reaching the light-

sensitive elements

22 or 26 respectively, While permitting light from each of those electrodes to reach and actuate the light-

sensitive elements

26 and 22 respectively, the inner walls of the aperture 4 are rendered opaque, in order to ensure that as much light as possible emanating from the proper electrode 16 or 18 impinges upon the light sensitive portion of the

elements

26 and 22, the inner walls of the apertures and 12 may be made light-reflective. if the material of which the housing 2 is formed is itself opaque, the inner walls of the aperture 4 will be inherently opaque, but if the housing 2 is formed of lighttransrnissive material, a suitable opaque coating may be applied to the inner walls of the aperture 4. If the inner walls of the apertures 16 and 12 are, by reason of the material of which the housing 2 is formed, inherently light-reflective, no further treatment is required, but if that is not the case a coating of suitable lightreflective material may be placed on the inn-er surfaces of the apertures 10 and 12. The result is that when the electrode 16 glows, as will be the case when it is sufficiently negative relative to the electrode 18, light will pass therefrom through the slot 6 to the aperture 10, impinging upon and actuating the light-sensitive element 26, while substantially no light from the glowing electrode 16 will pass through the slot 8 and impinge upon the light-sensitive element 22. In this regard it is preferred that the slot 8 be no wider than a projection of the electrode 18 thereon, so that the slot 8 will be in the shadow of the electrode 18 which is cast when the electrode 16 is illuminated. Similarly, when the electrode 18 is illuminated, as will be the case when an appropriate negative potential is applied thereto relative to the electrode 16, substantially all of the light from the electrode 13 will pass through the slot 8 and actuate the light-sensitive element 22, and substantially no light from the electrode 18 will reach the light-sensitive element 20.

The specific nature of the light-

sensitive elements

26 and 22 may be varied, providing only that they are sufficiently sensitive to the presence or absence of light to control external circuitry The use of PNPN silicon diodes for this purpose is highly desirable, not only because such devices are highly light-sensitive and are quite reliable, but also because they have an inherent latch- .ing effectwhen a sufficient amount of light impinges on such a device, the device is rendered conductive, and then will remain conductive, even if the light is removed therefrom, for so long as appropriate electrical potential is applied thereacross. When that potential is removed the device reverts to its non-conducting state, and will remain in that non-conducting state until again activated by light. In this way a utilization circuit connected to such a device may be rendered operative by light, the utilization circuit remaining in that operative status even after the initiating light impulse is no longer present.

FIG. 3 illustrates a circuit in which the assembly of FIGS. 1 and 2 may be utilized. Each of the light-

sensitive elements

20 and 22 is connected in series with a different utilization circuit, generically designated by the

resistances

24 and 26 respectively. The light-sensitive element 20 and its utilization circuit 24 are connected between power terminals 28 and 3t}, and the light-sensitive element 22 and its associated utilization circuit 26 are similarly connected between a pair of power terminals which, for purposes of convenience, may be the

same terminals

28 and 30. A commutating capacitor 32 is connected between corresponding ends of the light-

sensitive elements

20 and 22 respectively. The control signal is applied across

terminals

34 and 36, which are connected respectively to the electrodes 16 and 18 of the glow discharge tube 14. A resistance 38 may be connected in series in the control circuit, and a capacitor 40 may be connected between the electrodes 16 and 18.

Considering that the terminal 28 is positive and the terminal 3d is negative, the circuit of FIG. 3 will function as follows: At the start, when no light has reached either of the

elements

20 or 22, they both are non-conductive and no effective current will pass through either of the utilization circuits 2d and 26. If now an appropriate signal is applied across the

terminals

34 and 36, with the terminal 36 positive with respect to the terminal 34, the electrode 16 will glow, light will impinge upon the light-sensitive element 2%}, it will become conductive, and work current will pass thereth-rough and through the utilization circuit 24 associated therewith. The right hand side of capacitor 32 will become negative and the left hand side of the capacitor 32 will become positive. This situation will continue, with current flowing through the utilization circuit 24, While the electrode 16 continues to glow. If the control signal is removed and the electrode 16 stops glowing, there will be no change in the status of the utilization circuitscurrent will continue to flow through circuit 24 and no current will flow through circuit 26.

If now the control signal is reversed, the terminal 34 becoming positive and terminal 36 becoming negative, the electrode 18 will glow, light will impinge upon lightsensitive element 22, and it will become conductive, causing current to pass through the utilization circuit 26 associated therewith. This will cause the capacitor 32 to discharge and become charged in the opposite direction, applying a negative pulse to light-sensitive element 26 and therefore unlatching it-causing it to become non-conductive. Thereafter, while the electrode 18 continues to glow and even after the control signal has been removed and the electrode 18 stops glowing, the lightsensitive element 22 will remain conductive and lightsensitive element 20 will remain non-conductive, so that work current will flow through the utilization circuit 26 and no work current will flow through the utilization circuit 24.

Since the glowing of the electrodes 16 and 18 follows substantially instantaneously upon the appropriate energization thereof, and since the reaction of the light-

sensitive elements

20 and 22 to light impinging thereon is substantially instantaneous, switching action in the

utilization circuits

24 and 26 is extremely rapid, on the order of 1 or 2 milliseconds. Thus, by controlling the polarity of the signal applied to the

terminals

34 and 36 rapid and reliable switching of the

utilization circuits

24 and 26 is effected.

The circuit of FIG. 3 exhibits a unique characteristic which is very useful in many circumstances. If the control signal applied across the

terminals

34 and 36 were to alternate sufficiently rapidly, the electrodes 16 and 18 would alternately glow so rapidly that both light-

sensitive elements

20 and 22 would be rendered conductive at the same time. Hence, by controlling the nature of the control signal applied-D.C. in one sense, DC. in the other sense, or relatively rapid A.C.-one can selectively achieve the encrgization of one utilization circuit or the other or both simultaneously. The same characteristic of the circuit of FIG. 3 could be used to provide a safety factor-a malfunction in a controlled machine or the existence of some external event such as fire could so affect the control signal as to cause both of the

utilization circuits

24 and 26 to conduct simultaneously, and the resultant drawing of a high current from the

power terminals

28 and 36 could actuate an alarm or perform some other appropriate control function.

The assembly of FIG. 1, which includes all of the operative control parts of the system here described, is disclosed in more or less idealized form. As disclosed,

it will be apparent that the glow discharge tube 14 and the light-

sensitive elements

20 and 22. are mounted in protected condition, so that they are exceptionally resistant to shock, vibration or the like. The assembly may readily be encapsulated or otherwise enclosed so as to protect it against humidity, corrosive atmospheres, or other deleterious external influences. Electrical connections may readily be made to the operative parts thereof, and the assembly is well adapted to be incorporated, either on a breadboard or production basis, into a Wide variety of overall systems or apparatus. There are no moving parts and no current-carrying contacts which might arc, bounce or chatter. There are no magnetic fields which might adversely affect adjacent circuitry. The system and assembly is simple and reliable.

While but a single embodiment of the present invention has been here specifically disclosed, it will be apparent that many variations may be made therein, all within the scope of the present invention as defined in the following claims.

I claim:

1. A photoelectric switching system comprising a glow discharge tube having first and second electrodes and the characteristic that only one of said electrodes glows at a time depending upon its polarity when D.C. energization is applied to said tube, means for selectively operatively energizing said discharge tube with a polarity of one sense or the other, first and second light sensitive latching-type rectifiers in operative optical relation to said first and second electrodes respectively, first and second output circuits each comprising a D.C. source, a ditferent one of said rectifiers, and a load electrically connected to one another, and a capacitor electrically connected between corresponding ends of said first and second rectifiers.

2. In combination with the system of claim 1, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer stations, and first and second light path means extending substantially from separated portions of said primary aperture to said first and second outer stations respectively, said glow discharge tube being in said primary aperture with its first and second electrodes in operative optical registration with said first and second light path means respectively, said first and second light sensitive latching type rectifiers comprising first and second light sensitive elements in said first and second outer stations respectively and in operative optical registration with said first and second light path means respectively, and means for substantially preventing light from said first and second electrodes from reaching said second and first light sensitive elements respectively.

3. In combination with the system of claim 1, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer stations and first and second slots extending substantially from separated portions of said primary aperture to said first and second outer stations respectively, said glow discharge tube being in said primary aperture with its first and second electrodes in operative optical registration with said first and second slots respectively, and said first and second light sensitive latching type rectifiers comprising first and second light sensitive elements in said first and second outer stations respectively and in operative optical registration with said first and second slots respectively, the walls of at least some of said slots and aperture being opaque, said slots defining substantially the sole light transmissive paths between said primary aperture and said outer stations respectively.

4. In combination with the system of claim 1, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer apertures and first and second light path means extending substantially from separated portions of said primary aperture to said first and second outer apertures respectively, said glow discharge tube being in said primary aperture with its first and second electrodes in operative optical registration with said first and second light path means respectively, said first and second light sensitive latching type rectifiers comprising first and second light sensitive elements in said first and second outer apertures respectively and in operative optical registration with said first and second light path means respectively, and means for substantially preventing light from said first and second electrodes from reaching said second and first light sensitive elements respectively.

5. In combination with the system of claim 1, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer apertures, and first and second slots extending substantially from sepa rated portions of said primary aperture to said first and second outer apertures respectively, said glow discharge tube being in said primary aperture with its first and second electrodes in operative optical registration with said first and second slots respectively, said first and second light sensitive latching type rectifiers comprising first and second light sensitive elements in said first and second outer apertures respectively and in operative optical registration with said first and second slots respectively, the walls of at least some of said slots and apertures being opaque, said slots defining substantially the sole light transmissive paths between said primary aperture and said outer apertures respectively.

6. A photoelectric switching system comprising a glow discharge tube having first and second electrodes and the characteristic that only one of said electrodes glows at a time depending upon its polarity when D.C. energization is applied to said tube, means for selectively operatively energizing said discharge tube with a polarity of one sense or the other, first and second light sensitive PNPN rectifiers in operative optical relation to said first and second electrodes respectively, first and second output circuits each comprising a D.C. source, a different one of said rectifiers, and a load electrically connected to one another, and a capacitor electrically connected between corresponding ends of said first and second rectifiers.

7. In combination with the system of claim 6, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer stations and first and second light path means extending substantially from separated portions of said primary aperture to said first and second outer stations respectively, said glow discharge tube being in said primary aperture with its first and second electrodes in operative optical registration with said first and second light path means respectively, said first and second light sensitive PNPN rectifiers comprising first and second light sensitive PNPN elements in said first and second outer stations respectively and in operative optical registration with said first and second light path means respectively, and means for substantially preventing light from said first and second electrodes from reaching said second and first light sensitive elements respectively.

8. In combination with the system of claim 6, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer stations and first and second slots extending substantially from separated portions of said primary aperture to said first and second outer stations respectively, said glow discharge tube being in said primary aperture with its first and second electrodes in operative optical registration with said first and second slots respectively, and said first and second light sensitive PNPN rectifiers comprising first and second light sensitive PNPN elements in said first and second outer stations respectively and in operative optical registration with said first and second slots respectively, the walls of at least some of said slots and aperture being opaque, said slots defining substantially the sole light transmissive paths between said primary aperture and said outer stations re spectively.

9. In combination with the system of claim 6, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer apertures and first and second light path means extending substantially from separated portions of said primary aperture to said first and second outer apertures respectively, said glow discharge tube being in said primary aperture with its first and second electrodes in operative optical registration with said first and second light path means respectively, and said first and second light sensitive PNPN rectifiers comprising first and second light sensitive PNPN elements in said first and second outer apertures respectively and in operative optical registration with said first and second light path means respectively, and means for substantially preventing light from said first and second electrodes from reaching said second and first light sensitive elements respectively.

10. In combination with the system of claim 6, a polarized photoelectric assembly comprising a housing having a primary aperture, first and second outer apertures, and first and second slots extending substantially from separated portions of said primary aperture to said first and second outer apertures respectively, said glow discharge tube being in said primary aperture with its first and sec ond electrodes in operative optical registration with said 3. first and second slots respectively, and said first and sec- 0nd light sensitive PNPN rectifiers comprising first and second light sensitive PNPN elements in said first and second outer apertures respectively and in operative optical registration with said first and second slots respectively, the walls of at least some of said slots and apertures being opaque, said slots defining substantially the sole light transmissive paths between said primary aperture and said outer apertures respectively.

References tilted by the Examiner UNITED STATES PATENTS 2,208,147 7/1940 Eislen 250-228 X 2,727,683 12/1955 Allen et al 250-209 X 2,790,088 4/1957 Shive 307-885 2,967,945 1/1961 De Gier 250-211 X 2,997,596 8/1961 Vize 250-209 3,066,258 11/1962 Van Overbeek et al. 307-885 3,143,655 8/1964 Strandberg 250-239 RALPH G. NrLsoN, Primary Examiner. WALTER STOLWEIN, Examiner.

Claims

1. A PHOTOELECTRIC SWITCHING SYSTEM COMPRISING A GLOW DISCHARGE TUBE HAVING FIRST AND SECOND ELECTRODES AND THE CHARACTERISTIC THAT ONLY ONE OF SAID ELECTRODES GLOWS AT A TIME DEPENDING UPON ITS POLARITY WHEN D.C. ENERGIZATION IS APPLIED TO SAID TUBE, MEANS FOR SELECTIVELY OPERATIVELY ENERGIZING SAID DISCHARGE TUBE WITH A POLARITY OF ONE SENSE OR THE OTHER, FIRST AND SECOND LIGHT SENSITIVE LATCHING-TYPE RECITIFIERS IN OPERATIVE OPTICAL RELATION TO SAID FIRST AND SECOND ELECTRODES RESPECTIVELY, FIRST AND SECOND OUTPUT CIRCUITS EACH COMPRISING A D.C. SOURCE, A DIFFERENT ONE OF SAID RECTIFIERS, AND A LOAD ELECTRICALLY CONNECTED TO ONE ANOTHER, AND A CAPACITOR ELECTRICALLY CONNECTED BETWEEN CORRESPONDING ENDS OF SAID FIRST AND SECOND RECTIFIERS.