Light-responsive light-emitting diode display
First Claim
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1. An outdoor-installed light-responsive diode display comprising:
- a light-emitting diode circuit including a plurality of light-emitting diodes connected in series for emitting a large amount of colored light; and
a light-responsive current-controlling circuit responsive to intensity of ambient light and connected in series to said light-emitting diode circuit and including a light-responsive current-controlling element, responsive to said ambient light, for regulating current through said light emitting diode circuit, and varying current through said light-emitting diode circuit such that a larger current flows through said light-emitting diode circuit when exposed to a higher intensity of the ambient light.
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Abstract
A light-responsive light-emitting diode display comprises a light-emitting diode circuit including a series connection of light-emitting diodes and a light-responsive current-controlling circuit connected in series to said light-emitting diode circuit for supplying a current thereto in correspondence with the ambient brightness. A unipolar photo-transistor can provide a current above a predetermined minimum value and increasing with the intensity of incident lights and can absorb excess voltages when applied. Light-responsive current-control reduces the useless power dissipation, and all solid-state display provides a very long service life.
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Citations
19 Claims
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1. An outdoor-installed light-responsive diode display comprising:
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a light-emitting diode circuit including a plurality of light-emitting diodes connected in series for emitting a large amount of colored light; and a light-responsive current-controlling circuit responsive to intensity of ambient light and connected in series to said light-emitting diode circuit and including a light-responsive current-controlling element, responsive to said ambient light, for regulating current through said light emitting diode circuit, and varying current through said light-emitting diode circuit such that a larger current flows through said light-emitting diode circuit when exposed to a higher intensity of the ambient light.
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2. An outdoor-installed light-responsive diode display comprising:
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a light-emitting diode circuit including a plurality of light-emitting diodes connected in series for emitting a large amount of colored light; and a light-responsive current-controlling circuit, responsive to intensity of ambient light, connected in series to said light-emitting diode circuit and including a light-responsive current-controlling element for allowing a large current to flow when exposed to illumination of a high intensity of lights; said light-responsive current-controlling element having a saturating current versus voltage characteristic. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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11. A light-emitting diode display device comprising:
- a light-emitting diode circuit including a series connection of light-emitting diodes and a current-controlling circuit including a transistor having a source, a drain, a channel region and a gate region and being connected in series to said light-emitting diode circuit and having a window for introducing ambient light rays into said channel region and being operative so that the effective potential of said gate region varies in accordance with the intensity of the incident ambient light rays, to thereby vary the magnitude of the current to said light emitting diodes in accordance with ambient light.
- View Dependent Claims (12, 13)
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14. A light-emitting diode display device, comprising:
- a light-emitting diode circuit including a series connection of light-emitting diodes, and a current-controlling circuit including a photo-transistor having first and second semiconductor regions defining a current path therebetween and a photo-responsive portion for controlling current flow through said path, said path being connected in series to said light-emitting diode circuit.
- View Dependent Claims (15)
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16. A light-emitting diode lamp adapted for outdoor use comprising:
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a housing including a lamp base having two terminals; a front panel accommodated on the top of said housing and carrying a multiplicity of light-emitting diodes of a single color connected in series; a photo-transistor accommodated at a side portion of said housing and connected in series to said multiplicity of light-emitting diodes for continuously controlling the intensity of output light in accordance with the ambient light; the multiplicity of light-emitting diodes and the photo-transistor being optically isolated and electrically connected in series between the two terminals of said lamp base. - View Dependent Claims (17)
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18. A light-emitting diode display adapted for use in day and night ambient light conditions comprising:
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light-emitting diode unit means including at least one set of a predetermined number of light emitting diodes electrically connected in series, for generating an amount of light in accordance with the magnitude of the current applied thereto; ambient light responsive current-control means, electrically connected with said light-emitting diode unit means, for limiting the maximum magnitude of said current in accordance with the level of said ambient light; and means for optically isolating said current control means from said light-emitting diode unit means. - View Dependent Claims (19)
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Specification