Light measuring device

Claim 2

A light measuring device having a plurality of light sensitive elements and being arranged to selectively detect the outputs of said light sensitive elements, comprising: means for short-circuiting both terminals of the light sensitive element which is not required for detection in a light measuring mode selected out of different light measuring modes.

Claim 3

A light measuring device according to claim 1, wherein said light sensitive elements include a first light sensitive element for receiving a light flux coming from a middle part of a brightness measuring object and a second light sensitive element for receiving a light flux coming from the remaining part of the object excluding said middle part to be measured by said first light sensitive element.

Claim 4

A light measuring device according to claim 2, wherein said first and second light sensitive elements are arranged in one unified form with the second light sensitive element arranged to encompass the periphery of said first light sensitive element.

Claim 5

A light measuring device according to claim 2, wherein, when an averaging light measuring mode is selected, said short-circuiting means serves to connect said second light sensitive element in parallel with said first light sensitive element.

Claim 6

A light measuring device for a camera, comprising: (a) a differential amplifier having two input terminals and an output terminal; (b) first light sensitive means, connected between the two input terminals of said differential amplifier, for receiving a light flux coming from the middle part of a scene to be photographed; (c) second light sensitive means for receiving a light flux coming from the remaining part of said scene excluding the middle part to be measured by said first light sensitive means; and (d) selecting means, connected to said second light sensitive means, for short-circuiting said second light sensitive means when a spot light measuring mode is selected and for connecting the second light sensitive means in parallel with said first light sensitive means when an averaging light measuring mode is selected.

Claim 7

A light measuring device for a camera, comprising: (a) a differential amplifier having two input terminals and an output terminal; (b) first light sensitive means, connected between the two input terminals of said differential amplifier, for receiving a light flux coming from the middle part of a scene to be photographed; (c) second light sensitive means for receiving a light flux coming from the remaining part of said scene excluding the middle part to be measured by said first light sensitive means; and (d) selecting means, connected to said second light sensitive means, for short-circuiting said second light sensitive means when a spot light measuring mode is selected and for connecting the second light sensitive means in parallel with said first light sensitive means when an averaging light measuring mode is selected.

Claim 8

A light measuring device according to claim 5, wherein said differential amplifier comprises a pair of field effect transistors.

Claim 9

A light measuring device according to claim 6, wherein: (a) the two source electrodes of said pair of field effect transistors are connected in common; (b) there is provided a constant current source connected to said two source electrodes to supply a constant current to said source electrodes, an output stage of said constant current source being formed by a transistor; and (c) there is further provided voltage control means connected to said constant current source for making a voltage between the emitter and the collector of said transistor of the constant current source unvarying.

Claim 10

A light measuring device comprising: (a) first light sensitive means having a first light measuring range, (b) second light sensitive means having a second light measuring range different from the light measuring range of the first light sensitive means; (c) output means for producing an electrical signal, and (d) electric change-over switching means for short-circuiting only one of the light sensitive means which is not in use and connecting the other light sensitive means to said output means so as to apply the output signal of the other light sensitive means to said output means.

Claim 11

A light measuring device comprising: (a) first light sensitive means having a first light measuring range, (b) second light sensitive means having a second light measuring range different from the light measuring range of the first light sensitive means; (c) output means for producing an electrical signal, and (d) electric change-over switching means for short-circuiting only one of the light sensitive means which is not in use and connecting the other light sensitive means to said output means so as to apply the output signal of the other light sensitive means to said output means.

Claim 12

A light measuring device according to claim 8, wherein said first light measuring means is arranged to receive the light from the center of a scene.

Claim 13

A light measuring device according to claim 9, wherein said second light measuring means is arranged to receive the light from the periphery of the scene.

Claim 14

A light measuring device comprising: (a) output means for producing an electrical signal; (b) first light sensitive means having a first light measuring range, the first light sensitive means being functionally connected to said output means for supplying an electrical signal corresponding to the incident light thereon to said output means; (c) second light sensitive means having a second light measuring range different from the light measur1ng range of the first light sensitive means, the second light sensitive means being functionally connected to said output means for supplying an electrical signal corresponding to the incident light thereon to said output means; and (d) electric switching means for short-circuiting one of the light sensitive means which is not in use.

Claim 15

A light measuring device comprising: (a) output means for producing an electrical signal; (b) first light sensitive means having a first light measuring range, the first light sensitive means being functionally connected to said output means for supplying an electrical signal corresponding to the incident light thereon to said output means; (c) second light sensitive means having a second light measuring range different from the light measur1ng range of the first light sensitive means, the second light sensitive means being functionally connected to said output means for supplying an electrical signal corresponding to the incident light thereon to said output means; and (d) electric switching means for short-circuiting one of the light sensitive means which is not in use.

Claim 16

A light sensitive device according to claim 11, wherein said electric switching means is a selecting switch normally connected in parallel between said first light sensitive means and said second light sensitive means, and when desired, short-circuits said first light sensitive means and releases the parallel connection between said first light sensitive means and said second light sensitive means.

Claim 17

A light measuring device according to claim 11, wherein said first light sensitive means is arranged to receive incident light from the center of a scene.

Claim 18

A light measuring device according to claim 13, wherein said second light sensitive means is arranged to receive incident light from the periphery of the scene.

Claim 19

A light measuring device according to claim 14, wherein said second light sensitive means has a hollow light sensitive wall arranged outside said first light sensitive means.