System for receiving exposure inaccuracies in automatic cameras

Claim 2

In an electrical system for automatically determining exposure time in a camera, signal-generating circuit means for generating signals from which exposure time can be determined, calculating circuit means electrically connected with said signal-generating circuit means for receiving the signals generated thereby and for calculating a timing signal therefrom, timing circuit means electrically connected with said calculating circuit means for receiving said timing signal therefrom and for creating from said timing signal an eiectrical quantity the magnitude of which corresponds to the required exposure time, part of said signal-generating circuit means and said calculating circuit means being electrically connected with each other in a closed loop arrangement for eliminating the influence of temperature fluctuations and voltage source fluctuations from some of the signals from said signal-generating means, another part of said signal-generating circuit means and said timing circuit means being electrically connected with each other in a closed loop arrangement for eliminating the influence of temperature fluctuations and voltage source fluctuation from the rest of the signals from said signal-generating means, and switching circuit means electrically connected with said timing circuit means for responding to said electrical quantity for determining the exposure time, said switching circuit means consisting of elements which are influenced to a negligible extent by temperature and voltage source fluctuations, and all of said circuit means including amplifier units, all of said amplifier units of all of said circuit means being of identical structure.

Claim 3

The combination of claim 1 and wherein each of said amplifier units is in the form of an integrated Circuit.

Claim 4

The combination of claim 1 and wherein said signal-generating circuit means includes a photosensitive means for receiving light and providing an electrical quantity corresponding to light intensity and a logarithmic compression diode connected in series with said photosensitive means, said timing circuit means including a logarithmic expansion diode which corresponds to and balances said logarithmic compression diode for eliminating dependency upon temperature fluctuations.

Claim 5

In an electrical system for automatically determining exposure time in a camera, signal-generating circuit means for generating signals from which exposure time can be determined, calculating circuit means electrically connected with said signal-generating circuit means for receiving the signals generated thereby and for calculating a timing signal therefrom, timing circuit means electrically connected with said calculating circuit means for receiving said timing signal therefrom and for creating from said timing signal an electrical quantity the magnitude of which corresponds to the required exposure time, said signal-generating circuit means, said calculating circuit means, and said timing circuit means all being electrically connected with each other for eliminating the influence of temperature fluctuations and voltage source fluctuations on the operation of all of said circuit means, and switching circuit means electrically connected with said timing circuit means for responding to said electrical quantity for determining the exposure time, said switching circuit means consisting of elements which are influenced to a negligible extent by temperature and voltage source fluctuations, said signal-generating circuit means including a photosensitive means for receiving light and providing an electrical quantity corresponding to light intensity and a logarithmic compression diode connected in series with said photosensitive means, said timing circuit means including a logarithmic expansion diode which corresponds to and balances said logarithmic compression diode for eliminating dependency upon temperature fluctuations, a pair of additional diodes respectively connected in series with said logarithmic compression and logarithmic expansion diodes and a pair of resistors, one of which is a variable resistor, respectively connected to a pair of junctions one of which is situated between said logarithmic compression diode and the additional diode connected in series therewith and the other of which is situated between said logarithmic expansion diode and said additional diode connected in series therewith, said additional diodes and resistors balancing each other for eliminating the influence of temperature and voltage source fluctuations.

Claim 6

In an electrical system for automatically determining exposure time in a camera, signal-generating circuit means for generating signals from which exposure time can be determined, calculating circuit means electrically connected with said signal-generating circuit means for receiving the signals generated thereby and for calculating a timing signal therefrom, timing circuit means electrically connected with said calculating circuit means for receiving said timing signal therefrom and for creating from said timing signal an electrical quantity the magnitude of which corresponds to the required exposure time, said signal-generating circuit means, said calculating circuit means, and said timing circuit means all being electrically connected with each other for eliminating the influence of temperature fluctuations and voltage source fluctuations on the operation of all of said circuit means, and switching circuit means electrically connected with said timing circuit means for responding to said electrical quantity for determining the exposure time, said switching circuit means consisting of elements which are influenced to a negligible extent by temperature and voltage source fluctuations, said signal-generating circuit means including a photosensitive means for receiving light and providing an electrical quantity corresponding to light intensity and a logarithmic compression diode connected in series with said photosensitive means, said timing circuit means including a logarithmic expansion diode which corresponds to and balances said logarithmic compression diode for eliminating dependency upon temperature fluctuations, a pair of additional diodes respectively connected in series with said logarithmic compression and logarithmic expansion diodes and a pair of resistors, one of which is a variable resistor, respectively connected to a pair of junctions one of which is situated between said logarithmic compression diode and the additional diode connected in series therewith and the other of which is situated between said logarithmic expansion diode and said additional diode connected in series therewith, said additional diodes and resistors balancing each other for eliminating the influence of temperature and voltage source fluctuations.

Claim 7

The combination of claim 4 and wherein said resistors and additional diodes have with respect to said logarithmic compression and logarithmic expansion diodes a relationship for providing bias voltages which are substantially constant and independent of the electrical quantity corresponding to light intensity and the magnitude of the electrical quantity provided by said timing circuit means.

Claim 8

The combination of claim 5 and wherein said signal-generating circuit means further includes a pair of variable resistors for respectively introducing factors of film speed and magnitude of exposure aperture, and a pair of diodes respectively connected in series with said variable resistors, said signal-generating circuit means further including a pair of buffer amplifier units respectively connected electrically to junctions one of which is situated between one of said variable resistors and the diode connected in series therewith and the other of which is situated between the other of said variable resistors and the diode in series therewith, said calculating circuit means including an amplifier unit having subtraction and addition inputs and said buffer amplifier units respectively having outputs respectively connected to said subtraction and addItion inputs so that the dependency of said diodes and variable resistors respectively connected in series therewith on voltage source and temperature fluctuations is eliminated.

Claim 9

In an electrical system for automatically determining exposure time in a camera, signal-generating circuit means for generating signals from which exposure time can be determined, calculating circuit means electrically connected with said signal-generating circuit means for receiving the signals generated thereby and for calculating a timing signal therefrom, timing circuit means electrically connected with said calculating circuit means for receiving said timing signal therefrom and for creating from said timing signal an electrical quantity the magnitude of which corresponds to the required exposure time, said signal-generating circuit means, said calculating circuit means, and said timing circuit means all being electrically connected with each other for eliminating the influence of temperature fluctuations and voltage source fluctuation on the operation of all of said circuit means, and switching circuit means electrically connected with said timing circuit means for responding to said electrical quantity for determining the exposure time, said switching circuit means consisting of elements which are influenced to a negligible extent by temperature and voltage source fluctuations, said signal-generating circuit means including a pair of variable resistors for respectively introducing the factors of film speed and the magnitude of the exposure aperture and a pair of diodes respectively connected in series with said pair of variable resistors, said signal-generating circuit means further inclluding a pair of buffer amplifier units respectively having inputs connected electrically with a pair of junctions one of which is situated between one of said variable resistors and the diode connected in series therewith and the other of which is situated between the other of said variable resistors and the diode connected in series therewith, said calculating circuit means including an amplifier unit having subtraction and addition inputs and said buffer amplifier units respectively having outputs connected electrically with said subtraction and addition inputs for eliminating the dependency of said variable resistors and diodes respectively connected in series therewith on voltage source and temperature fluctuations.

Claim 10

In an electrical system for automatically determining exposure time in a camera, signal-generating circuit means for generating signals from which exposure time can be determined, calculating circuit means electrically connected with said signal-generating circuit means for receiving the signals generated thereby and for calculating a timing signal therefrom, timing circuit means electrically connected with said calculating circuit means for receiving said timing signal therefrom and for creating from said timing signal an electrical quantity the magnitude of which corresponds to the required exposure time, said signal-generating circuit means, said calculating circuit means, and said timing circuit means all being electrically connected with each other for eliminating the influence of temperature fluctuations and voltage source fluctuation on the operation of all of said circuit means, and switching circuit means electrically connected with said timing circuit means for responding to said electrical quantity for determining the exposure time, said switching circuit means consisting of elements which are influenced to a negligible extent by temperature and voltage source fluctuations, said signal-generating circuit means including a pair of variable resistors for respectively introducing the factors of film speed and the magnitude of the exposure aperture and a pair of diodes respectively connected in series with said pair of variable resistors, said signal-generating circuit means further inclluding a pair of buffer amplifier units respectively having inputs connected electrically with a pair of junctions one of which is situated between one of said variable resistors and the diode connected in series therewith and the other of which is situated between the other of said variable resistors and the diode connected in series therewith, said calculating circuit means including an amplifier unit having subtraction and addition inputs and said buffer amplifier units respectively having outputs connected electrically with said subtraction and addition inputs for eliminating the dependency of said variable resistors and diodes respectively connected in series therewith on voltage source and temperature fluctuations.

Claim 11

The combination of claim 1 and wherein said switching circuit means includes a timing capacitor electrically connected with said timing circuit means to be charged with said electrical quantity and an amplifier unit electrically connected with said timing capacitor to be triggered when the charge of said capacitor reaches a given value, said switching circuit means further including a constant voltage diode electrically connected with said amplifier unit of said switching circuit means for determining the trigger level thereof and said constant voltage diode having a dependency upon source voltage and temperature fluctuation which is sufficiently small to be negligible as compared to the trigger level of said amplifier unit of said switching circuit means.

Claim 12

In an electrical system for automatically determining exposure time in a camera, signal-generating circuit means for generating signals from which exposure time can be determined, calculating circuit means electrically connected with said signal-generating circuit means for receiving the signals generated thereby and for calculating a timing signal therefrom, timing circuit means electrically connected with said calculating circuit means for receiving said timing signal therefrom and for creating from said timing signal an electrical quantity the magnitude of which corresponds to the required exposure time, said signal-generating circuit means, said calculating circuit means, and said timing circuit means all being electrically connected with each other for eliminating the influence of temperature fluctuations and voltage source fluctuations on the operation of all of said circuit means, and switching circuit means electrically connected with said timing circuit means for responding to said electrical quantity for determining the exposure time, said switching circuit means consisting of elements which are influenced to a negligible extent by temperature and voltage source fluctuations, said signal-generating circuit means including a photosensitive means for responding to light intensity to provide an electrical quantity corresponding to light intensity and a logarithmic compression diode connected in series with said photosensitive means, and a buffer amplifier unit having an input electrically connected to a junction between said photosensitive means and said logarithmic compression diode, said signal-generating circuit means further including a pair of variable resistors for introducing the factors of film speed and magnitude of exposure aperture and a pair of diodes respectively connected in series with said pair of variable resistors, a pair of additional buffer amplifier units respectively having inputs connected electrically to a pair of junctions one of which is situated between one of said variable resistors and the diode connected in series therewith and the other of which is situated between the other of said pair of variable resistors and the diode connected in series therewith, said calculating circuit means including an amplifier unit having subtraction and addition inputs, said subtraction input being electrically connected with that one of said buffer amplifier units which is connected to the junction between said variable resistor for introducing the selected magnitude of the exposure aperture and the diode connected in series therewith and said addition input being connected to the outputs of the remaining two buffer amplifier units, so that said variable resistors and diodes respectively connected in series therewith operate to eliminate any dependency on temperature and voltage source fluctuations, said timing circuit meanx having a logarithmic expansion diode for balancing said logarithmic compression diode, and a pair of additional diodes respectively connected in series with said logarithmic compression and logarithmic expansion diodes and a pair of resistors one of which is a variable resistor respectively connected electrically to junctions one of which is situated between said logarithmic compression diode and the diode connected in series therewith and the other of which is situated between said logarithmic expansion diode and the diode connected in series therewith, for operating said timing circuit means and that part of said signal-generating circuit means which provides an electrical quantity corresponding to light intensity without dependence upon temperature and voltage source fluctuations, and said switching circuit means including a constant voltage diode which is influenced by voltage source and temperature fluctuations to a negligible extent as compared with the switching level of said switching circuit means, said timing circuit means and switching circuit means including amplifier units, and the latter amplifier units together with the buffer amplifier units and the amplifier unit of said calculating circuit means all having an identical construction and all being in the form of integrated circuits.

Claim 13

In an electrical system for automatically determining exposure time in a camera, signal-generating circuit means for generating signals from which exposure time can be determined, calculating circuit means electrically connected with said signal-generating circuit means for receiving the signals generated thereby and for calculating a timing signal therefrom, timing circuit means electrically connected with said calculating circuit means for receiving said timing signal therefrom and for creating from said timing signal an electrical quantity the magnitude of which corresponds to the required exposure time, said signal-generating circuit means, said calculating circuit means, and said timing circuit means all being electrically connected with each other for eliminating the influence of temperature fluctuations and voltage source fluctuations on the operation of all of said circuit means, and switching circuit means electrically connected with said timing circuit means for responding to said electrical quantity for determining the exposure time, said switching circuit means consisting of elements which are influenced to a negligible extent by temperature and voltage source fluctuations, said signal-generating circuit means including a photosensitive means for responding to light intensity to provide an electrical quantity corresponding to light intensity and a logarithmic compression diode connected in series with said photosensitive means, and a buffer amplifier unit having an input electrically connected to a junction between said photosensitive means and said logarithmic compression diode, said signal-generating circuit means further including a pair of variable resistors for introducing the factors of film speed and magnitude of exposure aperture and a pair of diodes respectively connected in series with said pair of variable resistors, a pair of additional buffer amplifier units respectively having inputs connected electrically to a pair of junctions one of which is situated between one of said variable resistors and the diode connected in series therewith and the other of which is situated between the other of said pair of variable resistors and the diode connected in series therewith, said calculating circuit means including an amplifier unit having subtraction and addition inputs, said subtraction input being electrically connected with that one of said buffer amplifier units which is connected to the junction between said variable resistor for introducing the selected magnitude of the exposure aperture and the diode connected in series therewith and said addition input being connected to the outputs of the remaining two buffer amplifier units, so that said variable resistors and diodes respectively connected in series therewith operate to eliminate any dependency on temperature and voltage source fluctuations, said timing circuit meanx having a logarithmic expansion diode for balancing said logarithmic compression diode, and a pair of additional diodes respectively connected in series with said logarithmic compression and logarithmic expansion diodes and a pair of resistors one of which is a variable resistor respectively connected electrically to junctions one of which is situated between said logarithmic compression diode and the diode connected in series therewith and the other of which is situated between said logarithmic expansion diode and the diode connected in series therewith, for operating said timing circuit means and that part of said signal-generating circuit means which provides an electrical quantity corresponding to light intensity without dependence upon temperature and voltage source fluctuations, and said switching circuit means including a constant voltage diode which is influenced by voltage source and temperature fluctuations to a negligible extent as compared with the switching level of said switching circuit means, said timing circuit means and switching circuit means including amplifier units, and the latter amplifier units together with the buffer amplifier units and the amplifier unit of said calculating circuit means all having an identical construction and all being in the form of integrated circuits.