Light emitting diodes with sensor segment for operational feedback
A light emitting device comprises a detector circuit and a light emitting diode (LED) die. The LED die includes a semiconductor stack grown on a substrate. The LED includes an emitter segment formed from one segment of the semiconductor stack. The LED die includes a photosensor segment formed from another segment of the semiconductor stack. The LED die includes a segmentation layer formed between the emitter segment and the photosensor segment. The segmentation layer electrically isolates the emitter segment from the photosensor segment. The LED die includes first electrodes configured to provide power to energize the emitter segment. The LED die includes second electrodes configured to send the current to the detector circuit. The detector circuit is configured to convert the current to a signal which provides operational feedback with respect to the emitter segment.
1. A light emitting device comprising:
an emitter segment a first semiconductor stack comprising an n-type material, a p-type material, and an active material between the n-type material and the p-type material;
a sensor segment electrically isolated from the emitter segment and including a second semiconductor stack of an n-type material, a p-type material, and an active material between the n-type material and the p-type material;
a transparent substrate disposed over both the emitter segment and the sensor segment; and
first and second electrodes disposed on the emitter segment.
2. The device of claim 1 , further comprising a trench between the first and the second semiconductor stacks.
3. The device of claim 2 , further comprising a transparent material in the trench.
4. The device of claim 1 , further comprising a first via formed through the active material and one of the p-type material and the n-type material of the emitter segment, the first via lined with an electrically insulating material and filled with an electrically conductive material.
5. The device of claim 1 , further comprising a second via formed through the active material and one of the p-type material and the n-type material of the sensor portion, the second via lined with an electrically insulating material and filled with an electrically conductive material.
6. The device of claim 1 , wherein the transparent substrate has a second surface facing away from the n-type material and opposite a first surface, and is configured to provide total internal reflection of some amount of light incident on the second surface.
7. The device of claim 1 , wherein the electrical insulating material completely surrounds the sensor segment.
8. A light emitting diode (LED) device system comprising:
a light emitting element comprising:
a semiconductor stack comprising an n-type material, a p-type layer, and an active material between the n-type material and the p-type material;
an electrical isolation region electrically isolating the semiconductor stack into a first segment and a second segment;
a driver circuit electrically coupled to the first segmentportion and configured to provide a drive current to drive the first segment as an emitter; and
a bias circuit electrically coupled to operate the second segment as a sensor segment and provide an input current to the driver circuit based on an amount of light impinging on the second segment.
9. The system of claim 8 , further comprising a transparent substrate disposed over both the first segment and the second segment.
10. The system of claim 9 , further comprising:
at least one anode electrode disposed on the light emitting element; and
at least one cathode electrode disposed on the light emitting element,
wherein each of the first segment and the second segment are electrically coupled to one of the at least one cathode electrode and one of the at least one anode electrode.
11. The system of claim 9 , wherein the transparent substrate has a second surface opposite a first surface and is configured to provide total internal reflection of light incident on the second surface of the transparent substrate.
12. The system of claim 8 , wherein the electrical isolation region comprises one of a trench and an insulating region of semiconductor material in the semiconductor stack.
13. The system of claim 8 , further comprising a controller configured to perform at least one of:
periodically switching the second segment between operation as an emitter and operation as a sensor, or
switching the second segment between operation as an emitter and operation as a sensor in response to a control signal.
14. The system of claim 8 , wherein the bias circuit is configured to bias the second segment to provide a positive voltage on a condition that light emitted by the first segment is below a threshold and provide a negative voltage on a condition that light emitted by the first segment is above the threshold.
15. The system of claim 8 , wherein the input current to the driver circuit adjusts the drive current higher on a condition that light emitted by the first segment is below a threshold.
16. A method of manufacturing a light emitting diode (LED) device, the method comprising:
growing an n-type material, a p-type material, and an active material on a substrate to form a semiconductor stack on the substrate;
etching a trench through the p-type material, the n-type material, and the active material to divide the semiconductor stack into an emitter segment and a sensor segment;
electrically coupling a respective first electrode directly to one of the p-type material and the n-type material of the emitter segment and the sensor segment;
forming a separate via through each of the emitter segment and the sensor segment; and
electrically coupling a respective second electrode to the other one of the p-type material and the n-type material through each separate via.
17. The method of claim 16 , further comprising filling the trench with a transparent material.