MONITORING DEVICE APPLYING NOCTOVISION FOR A DOORPHONE SYSTEM

Abstract: A monitoring device applying noctovision is used for a door-phone system which enables persons to talk between a branch door-phone device installed at the porch of a house and a main door-phone device installed indoors. Use is made of an imaging camera consisting of a solid imaging element or the like sensitive to infrared rays, whereby the casing of the branch door-phone device is formed in a compact size, the imaging camera is contained in the branch door-phone de­ vice to take a picture of a visitor without causing him to notice it, and the visitor is monitored on a monitor TV of the main door-phone device installed indoors. Since use is made of a solid imaging element which is sensitive to infrared rays, il­ lumination obtained by using infrared ray emitting means can be used to take a picture of the visitor without causing him to notice it. It is possible to photograph the visitor without giving him unpleasant feeling in the nighttime, too. The infrared ray emitting means can be made to operate for a predetermined period of time after the call switch is mani­ pulated, or only during a period of a call from the time when the call switch is manipulated until the time when a handset of the main door-phone device is returned to the initial posi­ tion, or when means for emitting light is operated, or only when the illuminance on the surface of the object is in­ sufficient, to prevent wasteful consumption of electric power. Further, the light-emitting operation of the infrared ray emit­ ting means can be brought into synchronism with video signals of the imaging camera to obtain illumination which makes it possible to take a picture without flickering.

Description: The invention refers to an over-door interphone system with the features of the preamble of the only claim. DE-A-3 113 997 discloses an over-door interphone system with the features of the preamble of claim 1, in which the light emitting illumination means is not infrared. The camera is not for infrared light, but only sensitive to a visible light. The camera is actuated when the call switch is pushed whereas the light emitting illumination means is switched on manually by a switch in the master station unit. No information whatsoever is given as to at what time and by what element the camera and/or the illumination means are deactivated. US-A-3 816 654 concerns an over-door interphone system with an infrared light emitting illumination means as well as an infrared camera. It is the object of the invention to provide an advantageous over-door interphone system by which a visitor can be observed in a very discrete manner and which in addition operates very simply and effectively. This object is solved by the features of the only claim. An embodiment of the invention is shown in the drawings, in which: Fig. 1 is a perspective view of a conventional remote station unit with a television camera shown in its installed condition; Fig. 2 is a perspective view of another conventional remote station unit with an incorporated television camera shown with a cover being removed; Fig. 3 is a schematic diagram of an over-door interphone system provided with a night-vision monitoring device in accordance with the first embodiment of the present invention; Fig. 4 is a front view of a remote station unit employed in the first embodiment; Fig. 5 is a side sectional view of the remote station unit of the first embodiment; Fig. 6 is a rear view of the remote station unit of the first embodiment with its base removed; Fig. 7 is a perspective view of a printed board and infrared light emitting diodes mounted thereon employed in the first embodiment of the present invention; Fig. 8 is a circuit diagram showing the connection of the infrared light emitting diodes of the first embodiment; Fig. 9 is a schematic view of a microphone and its associated parts, and Fig. 10 is a block diagram of an illumination controller employed in the invention. An over-door interphone system in accordance with the first embodiment of the present invention comprises a remote station unit 1 installed at an entrance of a house, a master station unit 2 installed inside the house and a signal transmission line 3 comprising an audio signal line and a video signal line connecting the remote station unit 1 and the master station unit 2 as shown in Fig. 3. The master station unit 2 comprises a video display 42 on which an object image obtained from a television camera 4 mounted in the remote station unit 1 is displayed and a hand set 5 for making a telecommunication with the side of the remote station unit 1. The remote station unit 1 includes a television camera 4, a call switch 7, a speaker 8, a microphone 9 necessary for the telecommunication means and so forth in a housing 6 thereof as shown in Figs. 4 to 6. The housing 6 consists of a cover 61, a chassis 62 and a base 63. The base 63 is provided with terminals 43 to which the signal transmission line 3 and a power supply line are connected. The television camera 4 is composed of an optical unit 10 which is coupled to a printed board 15 carrying thereon solid state camera 14 of CCD or MOS type by means of coil springs 12 and screws 13 passing therethrough. The coil springs 12 are provided to hold the optical unit 10 and the solid state camera 14 mounted on the printed board 15 in a suitable distance, whereby an object image is focused on the photosensitive target site of the solid state camera 14 through an optical lens means 101 of the optical unit 10. As shown in Fig. 7, the optical unit 10 includes a printed board 11 mounting centrally thereof a casing 102 which covers the solid state camera 14 on the printed board 15, and includes the optical lens means 101 received in the front opening of the casing 102. A light entering through the optical lens means 101 will pass inside of the casing 102 and through an opening (not shown) formed in the printed board 11 to be focused on the target site of the solid state camera 14 on the printed board 15. A display controller 34 for the television camera 4 including the optical unit 10 and the solid state camera 14 is formed on a printed board 18 mounted at a location sideward of the optical unit 10 and behind the speaker 8 for arranging the television camera 4 to have a reduced thickness. On either side of the casing 102 there are formed a suitable number of infrared light emitting diodes 16 producing infrared light for an illumination purpose. These infrared light emitting diodes 16 are preferably divided into groups A and B located respectively on both sides of the casing 102 with the infrared light emitting diodes 16 being series connected in each group. As shown in Fig. 8, the infrared light emitting diodes 16 forming the groups A and B are connected in parallel relation to an illumination controller 25 such that one circuit of the diode groups will operate to produce enough amount of illumination even if the other fails, providing safeguard against total illumination failure. An infrared light transmissive filter 33 is provided in an opening 61a of the cover 61 located in front of the optical unit 10 and the infrared light emitting diodes 16 in order to conceal the television camera 4 as well as the infrared light emitting diodes 16 from the eyes of the visitor. The printed board 18 carries the illumination controller 25 other than the display controller 34, while a printed board 18a beside the printed board 18 carries the call switch 7 for actuating the interphone system, the printed boards 18 and 18a being fixed to bosses 19 and 19a provided on the interior of the cover 61. A pushbutton 71 for the call switch 7 is urged by means of a coil spring 22 to project outwardly through a window 21 in the cover 61, the coil spring 22 being wound around a rib 72 projecting on the rear the pushbutton 71 and compressed between the enclosure of the call switch 7 and the pushbutton 71. When the pushbutton 71 is pressed against the bias of the coil spring 22, it pivots about an axis F1 to push an actuator button 73 of the call switch 7 at the end of the rib 72, actuating the call switch 7. On the other hand, there is provided in the center of the pushbutton 71 a widow 74 for passing therethrough light emitted from a position indicating light emitting diode 23 provided on the printed board 18. The speaker 8 for outputting a verbal message from the master station unit 2 is heat-welded to the cover 61 through a water-tight packing 20 while a microphone 9 for dispatching a verbal message from the remote station unit 1 is put in a rubber case 40 which is received in a cavity 24 of the cover 61 with a waterproof packing 41 interposed therebetween as shown in Fig. 9. The infrared light emitting diodes 16 are controlled by the illumination controller 25. The illumination controller 25 has a circuit configuration, as shown in Fig. 10 that a synchronizing signal from a camera synchronizing signal generator 26 is amplified in a signal amplifier 27 and then output to drive the infrared light emitting diodes 16. The infrared light emitting diodes 16 are driven to ensure a sufficient illuminance level in an intermittent manner generating no flicker under the control of the synchronizing signal in a synchronous relation with the input of a trigger signal from a calling circuit 29 in response to the call switch 7. As shown in Fig. 10, the illumination controller 25 is arranged so that the camera synchronizing signal generator 26 responds to the trigger signal from the calling circuit 29 for driving the infrared light emitting diodes 16 in synchronous with the video signal of the television camera 4 until it receives from a handset detector 35 a signal indicative of the handset 5 being hung up of the master station unit 2 after termination of the telecommunication, which is in contrast to the above embodiments 1 and 2 in which the illumination controller 25 is arranged to include the timer 28 for driving the infrared light emitting diodes 16 for the predetermined period of time.

Claims: An over-door interphone system including a master station unit (2) located inside of a house and a remote station unit (1) located outside of an entrance door of the house which remote station unit (1) being connected to the master station unit (2) for telecommunication between a visitor and a dweller, said remote station unit (1) comprises: a housing (6); a television camera (4) mounted within the housing (6) to comprise an optical unit (10) including optical lens means (101) disposed in front thereof; control circuit means mounted adjacent to the optical unit (10) for controlling the same; call switch means (7) within the housing (6) for calling the master station unit (2); and telecommunication means within the housing (6) for telephonic intercommunication between the master (2) and remote station unit (1); and said master station unit (2) comprises a video display (42) for monitoring the image of the visitor picked up by said television camera (4); said system being characterized in that it comprises an infrared light emitting illumination means (16) and an illumination control means (25) mounted on the side of the master station unit (2) in order to actuate said infrared light emitting illumination means (16) to produce, upon being operated at the master station unit, the infrared light intermittently in synchronism with the operation of said television camera (4) for a time period starting from the actuation of said call switch means (7) and ending with the hang-up of a hand-set (5) provided on the side of the master station unit (2), wherein said camera (14) is a solid state camera (14) sensitive to said infrared light.

Inventors: HISANO TSUYOSHI, TATSUMI YOSHIKAZU, HISANO, TSUYOSHI, TATSUMI, YOSHIKAZU
Applicants: MATSUSHITA ELECTRIC WORKS LTD, MATSUSHITA ELECTRIC WORKS, LTD.
Application year: 1986
Main classification: H04N7
IPC codes: H04N7