Exposure control device

Claim 2

An automatic exposure control device adapted to be used in a camera comprising a first exposure control means for controlling the quantity of light passing through the exposure lens of the camera to give a correct exposure according to the brightness of an object to be photographed or televised, a second exposure control means including a plurality of filters of different transmitivity and means for selectively bringing one of said filters into the optical path of the exposure lens, and a filter selecting means for selecting one of said filters to bring the same into said optical path according to the level of brightness of the object.

Claim 3

An automatic exposure control device as defined in claim 1 wherein said filter selecting means comprises means for detecting the upper and lower limits of the control range of said first exposure control means, and means for changing said filters when said limit detecting means detects the limit of the first exposure control means, whereby the range of exposure control is substantially increased.

Claim 4

An automatic exposure control device as defined in claim 2 wherein said first exposure control means is a diaphragm the size of which is controlled by rotation of a diaphragm operating ring, said limit detecting means comprises a light source provided in the vicinity of said ring, a photoresponsive element provided to receive light emitted from said light source, and a light intercepting member provided on the periphery of the diaphragm operating ring to indicate the size of the diaphragm by the position thereof and intercept the light from the light source to prevent the photoresponsive element from receIving the light by coming into the position between the light source and the element, and said filter changing means comprises an electric circuit for energizing a driving motor to operate said second exposure control means to select one of said filters according to the output of said photoresponsive element.

Claim 5

An automatic exposure control means as defined in claim 3, wherein a photocoupler is used as said light source and said photoreceptor.

Claim 6

An automatic exposure control means as defined in claim 4, wherein said position regulating means comprises a light source disposed in the vicinity of the periphery of said filter turret, a photoreceptor for receiving the light from said light source, a light intercepting member provided on the periphery of the turret for intercepting the light from the light source to prevent the photoreceptor from receiving the light by coming into such a position to intercept the light as the turret rotates, and means for stopping the rotation of the turret upon interception of the light by detecting the output of said photoreceptor.

Claim 7

An automatic exposure control means as defined in claim 1 wherein said second exposure control means is a filter turret having a plurality of filters of different density arranged around the center of rotation of the turret.

Claim 8

An automatic exposure control means as defined in claim 6, wherein said filter turret is provided with a position regulating means for selectively stopping the turret at one of predetermined positions to bring one of said filters in alignment with the optical path of the exposure lens of the camera.