Multiwavelength LED devices and methods of fabrication
First Claim
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1. A multiwavelength light emitting diode device comprising:
- a first light emitting diode constructed to emit light of a first wavelength and a second light emitting diode constructed to emit light of a second wavelength, different than the first wavelength, the first and second light emitting diodes being stacked together and positioned to both emit light in the same direction, and one of the first and second light emitting diodes being transparent to light emitted by the other of the first and second light emitting diodes, whereby light from both of the first and second light emitting diodes is emitted through a common aperture at a surface of the device, each of the first and second light emitting diodes including an active layer of material sandwiched between two confinement layers of material and first and second electrical contacts positioned with the two confinement layers and active layer sandwiched therebetween, the first electrical contact of each of the first and second light emitting diodes being formed with a first type of conductivity, and the second electrical contact of each of the first and second light emitting diodes being formed with a second type of conductivity, the first and second light emitting diodes being stacked together with the first electrical contact of the second light emitting diode being positioned in overlying contact with the second electrical contact of the first light emitting diode, and the first electrical contact of the first light emitting diode being coupled to a common terminal and the second electrical contact of the second light emitting diode being coupled to the common terminal to electrically connect the first and second light emitting diodes in a push-pull configuration.
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Abstract
A multiwavelength LED device including a first LED constructed to emit light of a first wavelength and a second LED constructed to emit light of a second wavelength, different than the first wavelength. The first and second LEDs are stacked vertically on a substrate and positioned to both emit light in the same direction. One of the LEDs is transparent to light emitted by the other of the LEDs so that light from both LEDs is emitted through a single aperture and can be mixed in intensity to produce a variety of wavelengths. The LEDs are individually addressable.
129 Citations
16 Claims
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1. A multiwavelength light emitting diode device comprising:
a first light emitting diode constructed to emit light of a first wavelength and a second light emitting diode constructed to emit light of a second wavelength, different than the first wavelength, the first and second light emitting diodes being stacked together and positioned to both emit light in the same direction, and one of the first and second light emitting diodes being transparent to light emitted by the other of the first and second light emitting diodes, whereby light from both of the first and second light emitting diodes is emitted through a common aperture at a surface of the device, each of the first and second light emitting diodes including an active layer of material sandwiched between two confinement layers of material and first and second electrical contacts positioned with the two confinement layers and active layer sandwiched therebetween, the first electrical contact of each of the first and second light emitting diodes being formed with a first type of conductivity, and the second electrical contact of each of the first and second light emitting diodes being formed with a second type of conductivity, the first and second light emitting diodes being stacked together with the first electrical contact of the second light emitting diode being positioned in overlying contact with the second electrical contact of the first light emitting diode, and the first electrical contact of the first light emitting diode being coupled to a common terminal and the second electrical contact of the second light emitting diode being coupled to the common terminal to electrically connect the first and second light emitting diodes in a push-pull configuration. - View Dependent Claims (2, 3, 4)
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5. A multiwavelength light emitting diode device comprising:
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a first surface emitting, heterostructure light emitting diode including an electrically conductive first contact layer, a first confinement layer positioned on the first contact layer, a first active layer positioned on the first confinement layer, a second confinement layer positioned on the first active layer, and an electrically conductive second contact layer positioned on the second confinement layer; a second surface emitting, heterostructure light emitting diode including an electrically conductive first contact layer, a first confinement layer positioned on the first contact layer, a first active layer positioned on the first confinement layer, a second confinement layer positioned on the first active layer, and an electrically conductive second contact layer positioned on the second confinement layer; the first contact layers of the first and second light emitting diodes being a first conductivity type and the second contact layers of the first and second light emitting diodes being a second conductivity type; the first electrical contact layer of the second light emitting diode being positioned on the second contact layer of the first light emitting diode, and the first contact layer of the first light emitting diode being coupled to a common terminal and the second contact layer of the second light emitting diode being coupled to the common terminal to electrically connect the first and second light emitting diodes in a push-pull configuration; and one of the first light emitting diode and the second light emitting diode being substantially transparent to light emitted by the other of the first light emitting diode and the second light emitting diode, whereby light from both of the first and second light emitting diodes is emitted through a common aperture at a surface of the device. - View Dependent Claims (6, 7, 8, 9, 10)
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11. An array of multiwavelength light emitting diode devices comprising:
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a substrate having a planar surface; an array of devices formed on the surface of the substrate, the array being formed in rows and columns with a plurality of devices in each row and column; and each device in the array of devices including a first surface emitting, heterostructure light emitting diode including an electrically conductive first contact layer, a first confinement layer positioned on the first contact layer, a first active layer positioned on the first confinement layer, a second confinement layer positioned on the first active layer, and an electrically conductive second contact layer positioned on the second confinement layer; a second surface emitting, heterostructure light emitting diode including an electrically conductive first contact layer, a first confinement layer positioned on the first contact layer, a first active layer positioned on the first confinement layer, a second confinement layer positioned on the first active layer, and an electrically conductive second contact layer positioned on the second confinement layer; the first contact layers of the first and second light emitting diodes being a first conductivity type and the second contact layers of the first and second light emitting diodes being a second conductivity type; the first electrical contact layer of the first light emitting diode being positioned on the surface of the substrate and the first electrical contact layer of the second light emitting diode being positioned on the second contact layer of the first light emitting diode, and the first contact layer of the first light emitting diode being coupled to a common terminal and the second contact layer of the second light emitting diode being coupled to the common terminal to electrically connect the first and second light emitting diodes in a push-pull configuration; and the second light emitting diode being substantially transparent to light emitted by the first light emitting diode, whereby light from both of the first and second light emitting diodes is emitted through a common aperture at a surface of the device. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification