Electronic shutter for photographic camera

• US 3,922,691 A
• Filed: 12/17/1973
• Issued: 11/25/1975
• Est. Priority Date: 12/20/1972
• Status: Expired due to Term

• Current Assignee: Kunio Matsumoto
• Original Assignee: Kunio Matsumoto
• Inventors: Matsumoto, Kunio
• Primary Examiner(s): Matthews, Samuel S.
• Assistant Examiner(s): Hutchison, Kenneth C.
• Application Number:
  US05/425,291
• Time in Patent Office: 708 Days
• Field of Search: 354/131,133,234,266,267,295,67,48,50,51 340/221 343/225 352/179 95/53E,53EA,53EB
• US Class Current: 396/59
• CPC Class Codes: G03B 7/083 for control of exposure time
• CPC Class Codes: G03B 9/58 Means for varying duration of "open" period of shutter

Abstract

An electronic shutter for photographic cameras comprising a built-in receiving device which generates an output signal upon the reception of a wireless control signal in order to remotely control the opening and closing of the shutter. An electromagnet which opens and closes the shutter when it is energized and deenergized is connected to the receiving device when the receiving device is in stand-by condition for receiving a control signal, and then, when said electromagnet is energized by the output signal from the receiving device, connected to the exposure time control circuit which can control the energization and deenergization of the electromagnet.

Claims

1. An electronic shutter means for photographic cameras comprising a shutter, an electromagnet coupled to said shutter means for energizing said electromagnet so that said shutter is open when said electromagnet is energized and closed when said electromagnet is deenergized, an exposure time control circuit coupled to said electromagnet upon energization thereof and functioning to maintain said energized electromagnet in an energized condition and thereafter to deenergize said electromagnet after a time delay, a receiving device having a stand-by condition and responsive to a wireless control signal in said stand-by condition for generating an output signal, means responsive to said output signal for energizing said electromagnet energizing means when said receiving device receives a wireless control signal, and a change-over switch means coupling said electromagnet when it is deenergized to said receiving device, said change-over switch means being switched by energization of said electromagnet to thereby couple said electromagnet to said exposure time control circuit, said changeover switch means thereby connecting said electromagnet with said receiving device when said receiving device is in a stand-by condition for receiving the wireless control signal and with said exposure time control circuit in response to said receiving device receiving the wireless control signal.

2. An electronic shutter means for photographic cameras according to claim 1, including a switching circuit having a plurality of transistors and wherein:

said exposure time control circuit comprises a delaying circuit having a series connected photo-electric resistance element and a capacitor, said delaying circuit connected to said switching circuit, the resistance of said photo-electric resistance element being dependent upon ambient light level and said resistance element together with said capacitor forming an RC circuit for fixing the time delay during which the electromagnet is energized, said switching circuit coupling said delay circuit to said electromagnet upon energization thereof and said delay circuit functioning to maintain said energized electromagnet in an energized condition and thereafter to deenergize said electromagnet after a time delay.

3. An electronic shutter means for photographic cameras according to claim 1, wherein there is included a shutter release button and said change-over switch means is coupled to said shutter release button of the camera so that the switching operation of said change-over switch means can also be carried out by the depression of said shutter release button.

4. An electronic shutter means for photographic cameras according to claim 1, further comprising:

a power supply, an additional switching means coupling said power supply to said exposure time control circuit, said additional switching means controlled by the energization of said electromagnet, so as to interrupt electric power from said power supply to said exposure time control circuit when said receiving device is in said stand-by condition.