US 4,791,446 A · Light measuring device

Abstract

A light measuring device, for use in a camera having an objective lens, for measuring a brightness of a spot of an object, uses an autofocus detecting system which includes an array of light receiving elements for producing charges at a rate relative to an intensity of the light impinging thereon from the object, and a light receiver provided adjacent the light receiving element array for producing a photocurrent at an amount relative to an intensity of the light impinging thereon from said object. The charges produced from the light receiving elements are integrated in a plurality of charge accumulation portions, respectively, and the charges produced by the light receiver is integrated in a capacitor. A comparator is provided for comparing the integrated charges with a predetermined level, and for producing a stop integration signal when the integrated charges reaches the predetermined level so as to stop the integration in the first integration means. A spot brightness detector is provided for detecting the brightness of the sopt of the object using the integrated charges from the capacitor.

Claims38

Dependent claims

A light measuring device, for use in a camera having an objective lens, for measuring a brightness of a spot of an object, comprising:

first light receiving means having a plurality of light receiving elements for producing charges at a rate related to an intensity of the light impinging thereon from said object;
first integration means having a plurality of charge accumulation portions for integrating charge produced by corresponding light receiving elements;
second light receiving means provided adjacent said first light receiving means for producing a photocurrent at an amount relative to an intensity of the light impinging thereof from said object;
second integrating means for integrating charge produced by said second light receiving means;
comparing means for comparing said second integrated charge with a predetermined level, and for producing a stop integration signal when said integrated charge reaches said predetermined level, said stop integration signal being used for stopping the integration in said first integration means;
focus detection means for detecting the focus condition of said objective lens using the integrated charge data from said first integration means;
spot brightness detecting means for detecting the spot brightness of said spot of said object using the photocurrent from said second light receiving means;
and
exposure data calculating means for calculating exposure data based on the spot brightness.

6 more elements

A light measuring device, for use in a camera having an objective lens, for measuring a brightness of an object, comprising:

first light receiving means having a plurality of light receiving elements for producing charges at a rate related to an intensity of the light impinging thereon from said object;
first integration means having a plurality of charge accumulation portions for integrating charge produced from corresponding light receiving elements;
integration time control means for controlling the integration time in said charge accumulation portions so as to maintain said integrated charge at an appropriate level, and for storing said integration time;
focus detection means for detecting the focus condition of said objective lens using the integrated charge data from said first integration means;
brightness detecting means for detecting the brightness of said object using said integration time;
and
exposure data calculating means for calculating exposure data based on the detected brightness.

4 more elements

A light measuring device, for use in a camera having an objective lens, for measuring a brightness of an object, comprising:

light receiving means for receiving light from a predetermined area within a frame for focus detection of said objective lens;
focus detection means for detecting the focus condition of said objective lens in accordance with a result of the light received by said light receiving means;
first light measuring means for measuring a first light amount data in an area nearly equal to said predetermined area in the frame, and for calculating a first light amount data;
second light measuring means for measuring a second light amount data in another area in said frame, and for calculating a second light amount data;
reliability detecting means for detecting a lack of reliability of said first light amount data;
and
exposure data calculating means for calculating an exposure data based at least partially on said first light amount data when said reliability detecting means detects no lack of reliability of said first light amount data, and based at least partially on said second light amount data when said reliability detecting means detects the lack of reliability of said first light amount data.

4 more elements

Dependencies are inferred from the claim text.

Light measuring device

Life of this patent

Light measuring device

Life of this patent

Abstract

Claims38