Image reading device

Claim 2

The light emitting device in accordance with claim 1, wherein said total driving current control means comprises variable resistance means (Rv1) between said first and second power supply potentials, connected in series to the parallel connection of said first plurality of light emitting elements.

Claim 3

The light emitting device in accordance with claim 2, wherein said variable resistance means comprises a second plurality of resistance elements (R A , R B ) each being detachable.

Claim 4

The light emitting device in accordance with claim 1, wherein said total driving current control means comprises controllable power supply voltage generation means (40, 41) connected to said first power supply potential for supplying a controllable power supply voltage to the parallel connection of said first plurality of light emitting elements.

Claim 5

The light emitting device in accordance with claim 4, wherein said controllable power supply voltage generation means comprises, means for generating a third plurality of supply voltages (40) and selecting means (41) connected to said third plurality of power supply voltage generation means for supplying one of the third plurality of voltages selectively to the parallel connection of said first plurality of light emitting elements.

Claim 6

The light emitting device in accordance with claim 4, wherein said controllable supply voltage generation means comprises, a parallel connection of a fourth plurality of resistance elements (R A1 to R Am ) each connected to receive the first power supply potential, and the same fourth plurality of switching means (SW1 to SWm) each connected to one of said fourth plurality of resistance elements and having one selectively turned on.

Claim 7

The light emitting device in accordance with claim 1, wherein said first plurality of individual driving current control means comprise, a fifth plurality of prepared spare resistance elements (Rx1 to Rxk), and said first plurality of resistance elements (R1 to Rn) each connected in series to one of said light emitting elements and replacable with one of said fifth plurality of spare resistance elements.

Claim 8

The light emitting device in accordance with claim 1, wherein said first plurality of light emitting elements comprise said first plurality of light emitting diodes (D11-D14) arranged at least in said one direction.

Claim 9

The light emitting device in accordance with claim 1, wherein said light emitting elements comprise an information display device for displaying information determined by said first plurality of light emitting elements.

Claim 10

A light emitting device supplied with power by a constant current source, comprising: a plurality of light emitting elements (D11, D21, D31, D41) arranged at least in one direction, each of said light emitting elements being connected in parallel between said constant current source and ground, a plurality of individual driving current control means (R1, R2, R3, R4) each connected in series to a corresponding one of said light emitting elements for controlling individually a driving current flowing through said corresponding one of said light emitting elements, and total driving current control means (Rv2) coupled to said plurality of light emitting elements for controlling the total driving current flowing through said plurality of light emitting elements.

Claim 11

The light emitting device in accordance with claim 10, wherein said total driving current control means comprises variable resistance means (Rv2) between said constant current source and ground connected in parallel to the parallel connection of said plurality of light emitting elements.

Claim 12

An image reading device for reading a picture depicted on an applied original, comprising: light emitting means (33) for emitting light to be directed onto said original, and picture detecting means (38) responsive to an optical signal reflected from said original for detecting the picture depicted on said original, said light emitting means comprising, a first plurality of light emitting elements (D11, D21, D31, D41) arranged at least in one direction, each of said light emitting elements being connected in parallel between first and second supply potentials, the same first plurality of individual driving current control means (R1, R2, R3, R4) each connected in series to a corresponding one of said light emitting elements for controlling individually a driving current flowing through said corresponding one of said light emitting elements, and total driving current control means (Rv1) coupled to said first plurality of light emitting elements for controlling the total driving current flowing through said first plurality of light emitting elements.

Claim 13

An image reading device for reading a picture depicted on an applied original, comprising: light emitting means (22) for emitting light to be directed onto said original, picture detecting means (23) responsive to an optical signal reflected from said original for detecting the picture depicted on said original, and initializing light emitting means (28) for emitting initializing light to initialize said picture detecting means, said initializing light emitting means comprising, said first plurality of light emitting elements (D11, D21, D31, D41) arranged at least in one direction, each of said light emitting elements being connected in parallel between first and second supply potentials, said first plurality of individual driving current control means (R1, R2, R3, R4) each connected in series to a corresponding one of said light emitting elements for controlling individually a driving current flowing through said corresponding one of said light emitting elements, and total driving current control means (Rv1) coupled to said first plurality of light emitting elements for controlling the total driving current flowing through said first plurality of light emitting elements.