US3678823A — Electronic shutter for through-the-lens camera ha…

Claim 1

Independent Claim 438 words

In a through-the-lens camera having an electronically controlled shutter in which proper exposure is determined by measuring the light from the object to be photographed, and said camera accepts interchangeable objective lenses of differing maximum apertures, a system for adjusting the exposure of said camera when said through-the-lens light measurement is made either through a fully opened or a partially stopped-down diaphragm, which comprises, in combination: an electronically controlled shutter, including: a DC source; connected to said source an integrating circuit including: a photoelectric element receiving through the lens of said camera the light to be measured; a capacitor in series with said photoelectric element; and, a transistor having a base connected to the juncture of said capacitor and said photoelectric element for establishing a reference time interval proportional to the intensity of the measured light by triggering thereof as determined by the voltage across said capacitor and the emitter bias applied to said capacitor, said reference time interval being used in said electronically controlled shutter to determine the proper exposure; each interchangeable lens having: a diaphragm regulating member; a first coupling means mechanically interlocked with said regulating member; a switching member movable between either of two positions to cause said diaphragm regulating member to function in a first position as a manual diaphragm adjusting member and in a second position as a pre-set diaphragm regulating member for automatic operation; and a second coupling means mechanically interlocked with said Mechanically interlocked with said regulating member; said camera including: a resistor connected in parallel with said capacitor and said photoelectric element, and having a slideable contact thereon connected to said emitter to apply said emitter bias to said transistor; a first mating coupling means in said camera selectively engaging with the first coupling means in said lens, when said lens is mounted to said camera and connected to said slideable contact; a second mating coupling means in said camera selectively engaging with the second coupling means in said lens, when said lens is mounted to said camera, said first and second mating coupling means being interconnected with said switching member such that said first coupling means is coupled with said first mating coupling means when said switching member is set to one of said two positions and disengaged therefrom when said switching member is set to the other position, whereby the emitter bias is varied by said resistor in accordance with the setting of said diaphragm regulating member to achieve proper exposure when said switching member is set to said one position, and said emitter bias is held constant when said switching member is set to said other position.

Claim 2

Dependent Claim 438 words

In a through-the-lens camera having an electronically controlled shutter in which proper exposure is determined by measuring the light from the object to be photographed, and said camera accepts interchangeable objective lenses of differing maximum apertures, a system for adjusting the exposure of said camera when said through-the-lens light measurement is made either through a fully opened or a partially stopped-down diaphragm, which comprises, in combination: an electronically controlled shutter, including: a DC source; connected to said source an integrating circuit including: a photoelectric element receiving through the lens of said camera the light to be measured; a capacitor in series with said photoelectric element; and, a transistor having a base connected to the juncture of said capacitor and said photoelectric element for establishing a reference time interval proportional to the intensity of the measured light by triggering thereof as determined by the voltage across said capacitor and the emitter bias applied to said capacitor, said reference time interval being used in said electronically controlled shutter to determine the proper exposure; each interchangeable lens having: a diaphragm regulating member; a first coupling means mechanically interlocked with said regulating member; a switching member movable between either of two positions to cause said diaphragm regulating member to function in a first position as a manual diaphragm adjusting member and in a second position as a pre-set diaphragm regulating member for automatic operation; and a second coupling means mechanically interlocked with said Mechanically interlocked with said regulating member; said camera including: a resistor connected in parallel with said capacitor and said photoelectric element, and having a slideable contact thereon connected to said emitter to apply said emitter bias to said transistor; a first mating coupling means in said camera selectively engaging with the first coupling means in said lens, when said lens is mounted to said camera and connected to said slideable contact; a second mating coupling means in said camera selectively engaging with the second coupling means in said lens, when said lens is mounted to said camera, said first and second mating coupling means being interconnected with said switching member such that said first coupling means is coupled with said first mating coupling means when said switching member is set to one of said two positions and disengaged therefrom when said switching member is set to the other position, whereby the emitter bias is varied by said resistor in accordance with the setting of said diaphragm regulating member to achieve proper exposure when said switching member is set to said one position, and said emitter bias is held constant when said switching member is set to said other position.

Claim 3

Dependent Claim 196 words

The system according to claim 4 wherein said resistor includes a second, non-slidable contact selectively connectable to said emitter when said switching member is set to said other position; said camera further comprising: a rotatable ring mounting thereon said resistor and coupled with said second coupling means of the lens, when said switching member is set to said one position so that said resistor is physically displaced by an amount which corresponds to the aperture of the particular lens mounted to the camera when said resistor is located at a fixed position corresponding to the aperture of the largest available lens for said camera and the switching member is set to the other position, said slidable contact being shifted to selective, predetermined positions with respect to the camera corresponding to the diaphragm settings of said lens, as set by said diaphragm adjusting member, regardless of the aperture of the lens currently mounted to said camera, whereby the emitter bias of said transistor is differentially compensated for the setting of said diaphragm regulating member and the difference in aperture of the lens currently mounted to the camera when said switching member is set to said one position.

Claim 4

Dependent Claim 142 words

The system according to claim 4 wherein said resistor is located at a fixed position in said camera; said slidable contact is located at a position which corresponds to the largest possible aperture in an interchangeable lens for said camera, regardless of the largest aperture of the lens actually mounted to said camera when said switching member is set to said one position and said diaphragm regulating member is set to its fully opened diaphragm position so as to be shifted from said position by the operation of said regulating member while said second mating coupling means in the camera is disengaged from the second coupling means in the lens when said switching member is set to the other position to locate the slidable contact at the position corresponding to the largest aperture regardless of the operation of said diaphragm regulating member.

Claim 5

Dependent Claim 144 words

In an electronically controlled shutter for a camera, of the type that includes the series connection of a light sensitive device and a capacitor for gating on a transistor to establish a reference time interval of conduction proportional to the intensity of received illumination: means, coupled to the lens of said camera, for varying the bias of said transistor in accordance with the maximum aperture of said lens, whereby the correct duration for said reference time interval is established; and a ring extending about said lens a ring extending about said lens and operable between a first position for automatic exposure and a second position for manual exposure, said bias varying means including a resistor connected across said series connection and having first and second variable taps thereon, selectively connectable in accordance with the setting of said ring, to the emitter of said transistor.

Claim 6

Dependent Claim 144 words

In an electronically controlled shutter for a camera, of the type that includes the series connection of a light sensitive device and a capacitor for gating on a transistor to establish a reference time interval of conduction proportional to the intensity of received illumination: means, coupled to the lens of said camera, for varying the bias of said transistor in accordance with the maximum aperture of said lens, whereby the correct duration for said reference time interval is established; and a ring extending about said lens a ring extending about said lens and operable between a first position for automatic exposure and a second position for manual exposure, said bias varying means including a resistor connected across said series connection and having first and second variable taps thereon, selectively connectable in accordance with the setting of said ring, to the emitter of said transistor.

Claim 7

Dependent Claim 29 words

The shutter according to claim 4, wherein said first variable tap is varied in accordance with the aperture of said lens, when said ring is in said manual position.

Claim 8

Dependent Claim 30 words

The shutter according to claim 4, wherein said second variable tap is varied in accordance with the maximum aperture of said lens, when said ring is in said automatic position.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1975-07-25	1976-01-24	1976-07-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1979-07-25	1980-01-24	1980-07-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1983-07-25	1984-01-24	1984-07-25	$7700.00	Window Closed / Lapsed

Electronic shutter for through-the-lens camera having interchangeable lenses of differing aperture

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