FR1465008A - Photosensitive contactor device - Google Patents

Description

, Photosensitive contact device. The subject of the present invention is improvements to the photosensitive contactor devices. More particularly, the invention comprises a switch, or adapter, controlled by the light, to automatically turn on an electric lamp (or bulb) when the ambient light decreases and automatically extinguish said lamp (or bulb) when the ambient light becomes more intense , which switch, or adapter, is remarkable in that it comprises: a housing provided at one of its ends with a plug (or electrical outlet) arranged to be engaged in a lamp socket conventional and, at the other end, an electrical socket arranged to engage and electrically connect the base of the lamp to be powered or switched off by the photoelectric switch; a photosensitive device, such as a photocell, which can be placed away from the housing; light conducting means extending from the housing and electrically connecting the photosensitive device to the plug-socket; and electrical switch means, preferably a reed switch, connected to the socket and plug-socket, said interrupter means being controlled by the photosensitive device, whereby the closure of the electrical circuit between the plug is ensured; and the lamp socket of the housing, when the ambient light is low, and the opening of this circuit, when the ambient light becomes stronger.

In accordance with the present invention, improvements have been made to the structure, assembly and circuit elements, improvements whereby greater current control capability in a relatively small adapter is obtained on the one hand, and on the other hand, an increased sensitivity of the adapter to turn on and off automatically a lamp, or am hen. Other objects of the present invention are the production of a photoelectric control switch having a housing provided at one end with an electrical socket intended to receive the base of an electric lamp and, at the other, end, an electrical plug to be mounted on a source of electrical energy, switch means comprising a lamella switch, a coil contiguous to the lamella switch and a photoconductive device or photo sensitive, the lamella switch and the sleeve being connected, in series, to the plug, while the photoconductive device and the coil are connected, in series, to the plug, the two series of connections being associated, whereby when the plug is connected to the source and that the lamp is mounted in the socket, the lamp is powered or not by the operation of the lamella switch, in response to the degree of intensity of the lamp. first am biante striking the device; the distance, one from the other, of the photoconductive or photosensitive device from the case provided with the socket, the plug-socket and the switch-off means, and the use of flexible conductive means for connecting the photoconducting device to the housing; as an alternative, the assembly of all the switch elements, including the photoelectric cell, in a housing remote from the housing provided with the plug-socket and the socket, and the connection of the housing to said housing by drivers flexible; - As another variant, the combination of the lamella switch with a permanent magnet and the use of the magnetic effect of the coil to act against the influence of the magnet to actuate the magnet. lamella switch; the substitution of a heating coil for the aforementioned coil and the use of a permanent magnet whose strength decreases with the degree of heat of the heating coil; - As yet another variant, the realization of a socket for a light bulb, for the purpose of means for automatically switching the bulb on and off during changes in the intensity of the ambient light, including means by which ambient light is received over all (360) of the periphery of the socket, and also including means by which the direction in which ambient light controls the socket can be adjusted; - the use of a light which indicates, while the bulb carried by the socket is off, that the socket is under tension and that the filament of the bulb is whole; - The realization of a socket (for a light bulb) provided with means for automatically switching off and on the bulb, during the increase and decrease of the intensity of the ambient light, including means advanced interrupters by which stronger currents can be controlled, and also improved circuit elements providing increased sensitivity to changes in ambient light.

These and other objects as well as a better understanding of the invention will become apparent from the following description given with reference to the accompanying drawings, in which - Figure 1 is an elevational view of the combined housing with plug-socket and socket, according to a first embodiment of the invention, which view indicates in dashed line, the outline of a lamp, or bulb, lighting supported by the socket; FIG. 2 is an exploded view and in cross section, in a variant, of the main elements of the combined box with plug and socket, according to the invention; FIG. 3 is a cross-sectional view along line 3-3 of FIG. 1, showing the details of construction of the disc and the lower element of the embodiment shown in FIG. 2; - Figure d is a perspective view of the light transmitting disk; FIG. 5 is a diagram of the circuit according to the invention; FIG. 5d is another diagram according to the invention; FIG. 6 is a diagram of a variant of the circuit according to the invention; FIG. 7 represents another variant of the invention, variant in which the constituents of the circuit represented by the diagram are distant from each other; Fig. 8 is a cross-sectional view of a remotely located light-sensing tubular member containing the circuit elements of Fig. 7; - Figure 9, finally, is an external view of the lighting control sleeve and the tubular light receiving element placed at a distance from the variant shown in Figures 7 and 8.

The invention may, in general, be considered as a switch actuated by (or sensitive to) light, having at one end a socket for receiving a light bulb and, at the other end, a plug plug, intended to be electrically connected to a conventional lampholder, and associated with means for automatically switching on the bulb when the ambient light decreases and for automatically turning off the bulb when the ambient light becomes stronger.

In one of its embodiments, the invention may be considered as an adapter for a lamp, or bulb, of electrical lighting, adapter comprising: a tubular body, or casing, 1 e which is provided, at one of its ends, of a male electrical connector element, or plug, 12 arranged to be electrically engaged in a conventional lamp socket, and, at the other end, a socket 16 arranged to receive and electrically connect the base of the lamp 14 to be powered and unpowered; conductive means 66 coming out of the housing 18; a photosensitive device 54 (such as a photoconductive cell) remotely located and connected to the conductive means 66 which electrically connects the photosensitive device 54 to the housing 18; finally, contactor means 28 which can be accommodated in the housing 18 or in the photosensitive device and ensuring the closing of the circuit between the plug 12 and the socket 16 of the housing 18, when the ambient light is weak, and the opening of this circuit, when the ambient light becomes stronger.

In another variant, the invention may additionally comprise a light transmitting disk 4 # 2 having a coaxial conical recess 44 and coaxially supported to said body, or housing, 18 where it forms a portion, the periphery of this disk forming a part of the periphery of said body, or casing 18. In this embodiment, however, the photoconductive element 54. is mounted inside the body, or casing 18, adjacent to the disk 4.2 and at the top of the aforementioned recess formed in this disc, and the circuit which is inside said body, or housing, controls the continuity of the circuit between the plug 12 and the socket 16, said circuit being controlled by the photoconductive cell 54.

In FIG. 1, the entire contactor device which will subsequently be called adapter <B> </ B> and which forms the subject of the invention, is designated by 10. At one end of the adapter 10 is a threaded male plug 12 substantially identical to the base of the bulbs, or lamps, lighting manufactured at present. The adapter 10 is arranged to be screwed into a conventional light socket, instead of an ampoule, and to receive a lamp, or bulb, such as that represented by the silhouette 1-1, in the socket 16 located at the opposite end of the device. The adapter 10 may consist of a tubular body, or housing, 18 which terminates at one end with a plug 12 and at the opposite end with a socket 16 for receiving a bulb.

In another embodiment, a light receiver, which will be described in detail later, constitutes a portion of the tubular body, or housing, 18, and is placed between the plug 12 and the socket 16.

2 shows, exploded sectional view, an adapter according to one of the embodiments of the invention. The tubular body portion 18 is housed and receives the plug 12 secured with screws 21. The plug 12 is of usual construction as in the light bulbs and comprises a metal contact pad 22 and a part annular threaded contactor 24, separated from the pellet by an insulating portion 26.

A lamellar switch 28 of the commercially available type is housed within the tubular body 18. Commercially available switches, switches having either a normally open-contact arrangement or a normally-contact arrangement closed, are manufactured, for example, by: Hamlin, Inc .; Lake Mills, Wisconsin; Sylvania, Ipswich, Massa chusetts; General Electric Company, Clifton, New Jersey; and Gordos Corporation, Bloomfield, New Jersey. Three of these types of lamella switches are suitable for the desired purpose; these are Hamiin DRS-1, Sylvania MS-702, and Gordos MR-990. The conventional lamellar switch 28 consists of a glass envelope, empty of air and enclosing two parallel and contiguous metallic contacts which can be brought into contact with each other by magnetic forces acting on each other. outside. In the form described, the slat switch 28 is surrounded by a coil 30 and a small annular permanent magnet 32. The role of the coil and the magnet will be described later. Magnet 32 is preferably a ceramic magnet, although other types of permanent magnet function satisfactorily.

The tubular part, or casing, 18 is provided with a rim, or collar, outside 34, and it is the same for the sleeve 16 (intended to receive the bulb) which is also provided with a flange 36. The bushing 16 is supported by the tubular body 18 by means of the screws 38. The bushing 16 is provided with a metal part 40 threaded internally and with a pellet 42 able to come into contact with the base of a bulb. these two parts of the socket ensuring the bipolar electrical contact with the base of the bulb.

The light receiving portion 20 of the device is interposed between the flanges 34 and 36. The fundamental element of the light receiver 20 is a disk 42 made of clear plastic acrylic resin, such as that manufactured and sold under the trademark Lucite. The characteristic of this material is the efficient transmission of light. A conical recess 444 coaxially formed in the disk 4.2 converges at a vertex 46 on one of the faces of the disk. The light striking the periphery 18 of the disk 4.2 propagates in the centripetal direction inwardly and falls on the wall or conical face of the recess 44 from which it is reflected towards the inside of the tubular body 18. To increase the light transmittance of the disk -12, it is preferably provided with a coating such as a paint on its opposite planar faces, with the exception of a window 52 surrounding the top <16 of the recess 44.

A photoconductive cell (or element) 5-1 is disposed inside the tubular body 18, and is directly contiguous with the window 52 formed in the coating of the disk 42.

As can be seen in FIGS. 2 and 3, according to another variant of the invention, it is possible to provide a protection screen 56 in the form of a ring whose thickness is substantially equal to that of the disk 42. and whose inner diameter is slightly larger than the outer diameter of this disc. The shield 56 may be of any material such as metal or opaque plastic, and has on one side thereof a clear window area 58, as seen in FIGS. 1 and 3. This clear window 58 may be an uncoated part of the ring or be constituted, according to a variant, by a complete absence of material in this zone, the screen, or ring, being thus only a partial ring, at instead of being an entire ring. The shield 56 is rotatably mounted around the periphery of the disc 42 to prevent light from striking the disc and thereby to be transmitted and reflected back to the photoconductive cell (or member) 54 at the same time. With the exception of the light entering through the window 58, the use of a rotatable shield 56 allows the selection of the direction from which the ambient light will have to come to control the circuit of the device.

In the embodiment according to FIG. 2, the photoconductive cell may be at a distance, as indicated at 54A. In this arrangement, a tubular receiving member 60 is used to carry the photoconductive cell. An elastic clip 62 may be attached to the outer base of the tabular receiving member 60. The clip 62 has substantially the shape of a conventional pencil or pen clip, and thanks to it, the tubular base may be mounted easily on various objects then serving as a support for the element 60. A filter 64 of adjustable opacity can be placed inside the tubular receiving element 60, in the direct vicinity of the photoconductive element 54, to form an intermediate path through which light can be propagated to hit the photoconductive element, the filter 64 constituting a means for adjusting the sensitivity of the photoelectric switch. Conductors 66, preferably of the flexible type, leave the output of the photoconductive means 54A and pass through an opening 68 formed in the tubular body 18, these conductors serving to connect the photoconductive element 51 to the other components of the circuit, lying - inside the tubular body.

FIG. 2 shows the arrangement, previously described, of the photoconductive cell (or element) 54 in both the inner and outer positions, it being understood that under no circumstances will it be necessary at the same time two photoconductive devices and that; according to the invention, only one or the other will be used. When a photoconductive cell 54.A is used externally, the light receiving portion 20 of the tubular body 18 is suppressed, and likewise; in the case where the light-receiving portion-20 and the photoconductive element 54. are placed inside, the outer photoconductive cell 54.A is suppressed.

According to the present invention, an indicator light 70 mounted in the second opening 72 of the tubular body 18 may optionally be used. The purpose and the purpose of the indicator light will be described later.

Figure 5 shows a circuit diagram showing the relationship between the electrical components of the photoelectric switch device. Electrical energy is supplied to terminals 22 and 24 of plug 12 connected to a power source. The electrical energy is fed, by conductors - 74, to the connection, in series, of the lamella switch 28 and the part 4.0 in contact with the bulb, on the one hand, and to the part s12 which is in contact with the central contact of the bulb, on the other hand, the two parts 40 and 42 belonging to the lighting socket 16. Thus, when the switch 28 is closed, the bulb 14 is powered, and when opened, the bulb, unpowered, - is extinguished.

The magnet 76 is disposed around the switch 28, so that when said switch 28 is normally open, the magnet 76 causes the switch to close. In addition to the magnet 76, a coil 30 is arranged around the switch 28. The cell or photoconductive element 51 and a diode 78 are connected to the terminals 22 and 21 of the plug 12 and in series with the coil 30. A capacitor 80 is connected in parallel with the coil 30. The photoconductive cell, itself, may comprise a photoconductive device, or this photoconductive device may comprise the diode alone or the diode and the capacitor.

The operation of the device described with reference to FIG. 5 is as follows: when the plug 12 is screwed into a live lighting lamp socket, the electrical energy is supplied to terminals 22 and 2-1. As previously indicated, the magnet 76 normally holds the switch 28 closed and the electrical energy is supplied via this switch to the contacts 40 and 42 of the part that receives the light bulb. ; so that a bulb 14. mounted there is energized. When the ambient light strikes the photoconductive cell (or photoconductive element) 52, whether it is inside the body <B> 18 </ B> or outside and away from that body (as it is see in the upper left of Figure 2), said cell becomes more conductive. When the current flows through the photoconductive cell 54, it is rectified by the diode 78-and crosses. As a unidirectional current, the coil 30: The role of the capacitor 80 - is to equalize the current flowing through coil 30, so that it effectively becomes a DC current. When the intensity of the ambient light impinging on the cell 54 continues to increase, the current of the coil 30 continues to increase. The magnetic effect of the current in the coil 30 acts. against the force of the magnet 76, so that when the magnetic effect of the coil 30 exceeds that of the magnet 76, the contacts of the switch 28 open, thereby cutting off the current at 4 and 42 of the bulb 16 and extinguishing the light bulb As long as the ambient light struck the conductive photocell 51 is sufficient to allow the passage, in the coil 30, of a sufficient current. In order to overcome the effect of the magnet 76, the switch 28 remains open and the bulb 1 remains extinguished As the ambient light decreases, the current flowing through the coil 30 decreases until that the magnetic effect of the magnet 76 causes the switch 28 to close.

When the lamella switch 28a is of the normally closed contact type (Fig. 5a), the permanent magnet 76 can be omitted and only the coil 30a can be used, in which case the coil 30a should have a sufficient number turns to open the contacts of the switch when it is turned on. In another variant of the invention, it has been provided, as indicated above, an indicator light 70, preferably a neon bulb, which is connected in parallel with the switch 28. As shown in FIG. switch 28 is open, that is to say when the ambient light is strong, the bulb Izl is off and the voltage that then exists at the terminals of the indicator light 70 causes its ignition. This voltage appears only when the bulb 1-1, put in place, ensures electrical continuity between the points 4.0 and 42 of the socket 16. Thus, the indicator 70 will shine at moments of strong ambient light, indicating that energy is available on the lighting socket and the filament of the bulb mounted in the socket is not broken. This makes it easy to check, during the daytime hours, that the socket will work, as soon as the ambient light becomes weaker, to light the bulb, and that the bulb carried by the socket is in good condition.

A problem can arise, particularly in the case where the cell 54 is located inside the housing 18, a problem which is to prevent the light created by the bulb 14 from behaving as ambient light and thereby causing the opening of the switch. Such a phenomenon is capable of producing a pumping device, that is to say its ignition and extinction successive. To facilitate the elimination of this problem, a single variant of the invention comprises the interposition of a filter 82 (see Fig. 2) between the disk, 2 and the photoconductive element 51. The filter 82 may to be selective so as to pass freely only the light frequencies of the light from the bulb 14. Thus, the photoconductive cell is made more sensitive to ambient light of the day and less sensitive to artificially created light. In addition, when the filter 82 has varying degrees of opacity, it provides a quick way to adjust the sensitivity of the device.

The adjustable opacity filter 6-1, used inside the tubular receiver 60 of the cell 54, located at a distance, can also be of a type that lets sunlight pass freely and attenuates the artificial light, so that the photoconductive cell placed at a distance is thus less sensitive to the light coming from the bulb 14.

It is thus seen that the adapter, according to this variant of the invention (FIG 2), has many advantages and has many improvements. The use of a Lucite disk 42 provides a means by which ambient light, which is 360 degrees around the adapter, is used to control this adapter. The use of a rotating disk 56 controls the direction by which ambient light arrives to drive the adapter. The use of a photoconductive device 51 placed at a distance provides, in the case of particular situations, the possibility of placing the photoconductive device in the most advantageous locations in order to efficiently actuate the photoconductive device. switch under ambient light from a selected source or direction. The improved arrangement of the circuit according to the invention makes that a circuit with a minimum number of components can be housed in small locations. The indicator 70 provides a means by which the state of the adapter which closes the circuit, as soon as the ambient light drops, is quickly indicated, even at times of strong ambient light.

Figure 6 schematically shows another variant of the invention. In this arrangement, a heating coil 86 is placed in series with the photoconductive device 5-1. The heating coil 86 is located in the immediate vicinity of the magnet 76 which, in this variant of the invention, is of the type in which the magnetic force decreases when the temperature rises. The barium ferrite ceramic type can serve as an example of such a magnet. The heating coil 86 is preferably a strong conductor, such as that sold under the trademark Nichrome. A resistor 88 is put in series with the photoconductive device 54 and with the heating coil 86, in order to limit the maximum current flowing through these elements.

The operation of the variant shown in Figure 6 is. in principle, identical to the operation of the embodiment shown in Figure 5 and described above. The resistance of the photoconductive cell 54 struck by a low intensity light is large and the heating coil 86 is traversed only by a relatively weak current. The heating coil 86 thus produces only a relatively small amount of heat and the magnet 76, cold, has a magnetic force sufficient to keep closed the switch 28 which supplies the power supply. the lighting bulb 1-1. When the photoconductive cell: r is struck by a greater amount of light, it becomes more conductive and allows the passage of a more intense current in the heating coil 86, whose heat thus generated raises the temperature of the magnet When the temperature of the magnet 76 reaches a point where the magnetic force has dropped sufficiently, the switch 28 opens causing the lamp 14 to extinguish. When the intensity of the light striking the Photoconductive cell 54 decreases, the current decreases until the magnet 76 has cooled sufficiently and the magnetic force, thus increased, causes the closing of the switch 28 and the powering up of the bulb 14. To avoid the influence of the magnetic action induced on the switch 28, the coil 86 comprises a double winding, that is to say, it has approximately the same number of turns in both say ctions.

The opacity filter 64 and the filter 82 both shown in Figure 2 may be of the variable opacity type, preferably of the type in which the light transmittance of the filter is inversely proportional to the intensity of the light. Filters with this feature have been called photochromic. The use of such photochromic figures allows a more precise adjustment of the adapter subject of the invention.

Figures 7, 8 and 9 show another embodiment of the invention. In FIG. 7 there is provided an arrangement in which the adapter 10 has only a base 12, a socket 16 for receiving a light bulb, and an opening 68 containing an insulating bushing 90. In this arrangement, all the elements of the circuit are located outside, the circuit being identical to the circuit of FIG. 6, described previously.

8 is a sectional view on a larger scale of a tubular light detector 92 placed at a distance from the adapter 10. The remote light detector 92 contains the circuit of the light detector 92. FIG. 7. An auxiliary element mounted in the circuit is an indicator light 70 adjacent to a lens 94, which serves to indicate that the circuit is energized and that the filament of the bulb engaged in the socket 16 is good; to say that continuity is assured. The indicator 70 operates as has already been described with reference to FIG.

The light detector 92 is provided with an elastic clip, the assembly of which is designated by the reference numeral 96 and which is used to hook the detector to a nail or the like, so that the opening 98 of the The lens receiving the light can be easily oriented to detect ambient light, such as daylight, or to detect any other light that may act on the adapter. The resilient clip 96 may be attached to the shade of a lamp.

Three elements are arranged between the illumination aperture 97 and the photoconductive element 54 and have distinct functions. The first element is an optical filter 98, which, in the particular application of the invention, that is to say to ensure the exciteration of the adapter as soon as the intensity of the daylight decreases, is chosen so as to let in daylight and to attenuate the artificial light. Optical filter 98 therefore makes the photoconductive element mainly sensitive to daylight, however, since in other applications light from other sources may be used to drive the adapter, in which case the filter 98 will be chosen to have the minimum attenuation for the desired light frequency.

The second optical element is a photochromic filter 100. Photochromic glass, recently available, is characterized by an opacity proportional to the intensity of light. The photochromic element 100 thus serves as a compensation filter allowing more light to enter, when the light intensities are weak, and limiting the light that strikes the photoconductive cell 54, when the light intensities are high. This serves as protection for the photoconductive cell 54 and makes possible the use of an element which allows the light detector 92 to be placed to receive direct sunlight. The photochromic element 100 causes the photoconductive cell 54 to not be damaged by excessive light intensity and, simultaneously, that a lower luminous intensity is detectable.

The third optical element is an adjustment filter 102. This filter is simply an opaque filter, the degree of opacity being chosen as a means of adjusting the sensitivity of the device. When the device is placed to receive a high intensity of daylight, a high attenuation adjustment filter 102 is used, so that the e. Photoconductor 54 is not excited. On the other hand, if the device is set to detect only low light intensities, the adjustment filter 102 will be almost clear and, of course, it will be quite eliminated in the case of very low light intensities.

The difference between the photochromic filter 100 and the setting filter 102 is that the latter, which has been available for a long time, has an invariable opacity and is used solely for adjustment while the photochromic filter 100 is an automatic self-compensation element.

Figure 9 is an external view of the adapter 10 and the end-of-end light detector 92.

The variant shown in FIGS. 7, 8 and 9 has certain advantages and disadvantages with respect to the embodiments described above, the main advantage being that the light-detecting element can be placed in a more favorable manner to detect the variations in ambient light. This embodiment makes it possible to give the adapter a shorter length. Another important additional advantage of the embodiment of FIGS. 7, 8 and 9 is that since the light detector element 92 is placed at a distance, it does not subject the circuit elements to the heat of the light bulb. The disadvantage is that this embodiment comprises two main parts which must be connected to each other by a three-conductor cable 104.

Although the invention has been described with its many peculiarities, it is obvious that it is possible to make many changes in the construction details, without departing, for this, the spirit of the invention.

Claims (1)

SUMMARY An object of the present invention is a light-operated contactor device for automatically turning on an electric lamp when the ambient light decreases and for automatically extinguishing the lamp when the amber light becomes stronger, this contactor device being noted by the following points: and their combinations II comprises: a housing which has at one end a base arranged to engage and provide an electrical connection in a conventional lamp socket, and at the other end a socket arranged to receive (and ensure an electrical connection) the base of the lamp to be powered and unpowered; flexible conductive means extending from the housing; a photosensitive device located remote from said housing, said conductive means electrically connecting said photosensitive device with said base; and electrical switch means controlled by said photosensitive device and by virtue of which the electrical continuity between said base and said socket is ensured, when the ambient light is weak and the interruption of this continuity, when the ambient light becomes more intense; The photosensitive device comprises a photoconductive cell; The electrical switch means comprise a lamella switch; The electrical switch means comprise a lamella switch and a coil associated with this switch; The electrical switch means are disposed in said housing and the sensitive photo device is at a distance from said housing; The photosensitive device and the electrical switch means are disposed in a housing remote from said housing; The coil comprises an electromagnetic coil; 8 The coil is a heating coil; The switch means comprise a permanent magnet associated with the lamellar switch and the coil; The lamellar switch and the socket are connected in series with the cap, and the photoconductor device and said coil are connected in series with the cap, so that when the cap is connected to a power source and the lamp is mounted in the socket, said lamp is energized and de-energized by the operation of said interrupter in response to the degrees of intensity of ambient light striking the photoconductor device; The lamellar switch and the coil are housed in the housing, with light conductive means connecting the photoconductive device and the coil in series with the cap; The permanent magnet is associated with the slat switch in such a way that the lamp is switched on and off by the operation of the switch, under the influence of the magnetic effect, in the opposite direction, produced, by the coil, on the antenna, in response to the degrees of intensity of the ambient light striking the photoconductor device when the cap is connected to the power source; The coil associated with the lamellar switch is a heating coil, the lamp being switched on and off by the operation of said lamellar interrupter, under the influence of the heating produced by said coil acting on the coil. against the magnetic effect of the permanent magnet, the response to the degrees of intensity of the amber light striking the photoconductive device; There is provided a housing remote from the housing, the lamella switch, the heating coil and the permanent magnet being disposed in said housing; The housing of the housing is connected in series with the lamella switch and an indicator light is mounted inside the housing which has an opening for this indicator, which indicator is connected in parallel with said switch; The housing has at least a portion made of a transparent material and the conductive photo device is mounted within said housing, near the transparent portion of this housing; The housing is in the form of a tubular body having a socket at one end and a cap at the other end, which housing comprises a transparent acrylic resin disc mounted coaxially in said housing, this disc , the periphery of which forms a part of the periphery of the housing, having a central conical recess; Between the disk and the photoconductor device there is arranged an optical filter arranged to select the light frequencies; The clear acrylic resin disk is provided with a coating on its two flat faces, with the exception of a zone forming a bare window around the apex of the conical recess, adjacent to the photoconductive device; An opaque protective ring is rotatably mounted on the outside of the disc, said protective ring having in one of its parts a clear window area; An opaque optical filter, in the form of a thin disc, is mounted inside the housing between the resin disc and said photoconductive device; When the slat switch is of the normally open type, the surrounding coil is actuated by the photoconductive device to close the switch when the ambient light striking the photoconductor device drops below a predetermined value. 23 - When the switch <B> to </ B> lamellae is of the type normally closed by a permanent magnet which is contiguous thereto, the coil arranged around said switch is actuated by the photo conducting device = so as to open this switch- when ambient light striking said photoconductive device reaches a predetermined value; 21. A diode is connected in series with the photosensitive device and with said coil, and a capacitor is connected in parallel with the coil; An elastic clip is mounted at an end of a tubular member enclosing the photosensitive device, which clip is in a diametral plane of said tubular member and proximate thereto; An opacifying tuning filter is disposed in the path of the light incident on the photosensitive device; A second opening is provided in the housing of the device and the indicator light connected in parallel to the switch is disposed in the housing, close to this opening; The permanent magnet is a temperature sensitive magnet and the heating resistor is located in close proximity to the magnet; A neutral filter is provided on the path of light striking the photosensitive device; A photochromic filter is disposed in the path of the light striking the photosensitive device, said filter acting on the conductivity of the photosensitive device.