1. A multijunction photovoltaic cell, comprising:
a top subcell;
a second subcell disposed immediately adjacent to said top subcell, for producing a first photo-generated current; and including a sequence of first and second different semiconductor layers with different lattice constant; and
a lower subcell disposed immediately adjacent to said second subcell, for producing a second photo-generated current substantially equal in amount to the first photo-generated current.
2. A multijunction photovoltaic cell as defined in claim 1, wherein the sequence of first and second different semiconductor layers forms the base layer of the second subcell.
3. A multijunction photovoltaic cell as defined in claim 1, wherein the sequence of first and second different semiconductor layers comprises compressively strained and tensionally strained layers, respectively.
4. A multifunction photovoltaic cell as defined in claim 1, wherein an average strain of the sequence of first and second different semiconductor layers is approximately equal to zero.
5. A multijunction photovoltaic cell as defined in claim 1, wherein the first and second semiconductor layers are III-V semiconductor compounds, and the lower subcell is composed of germanium.
6. A multijunction photovoltaic cell as defined in claim 1, wherein each of the first and second semiconductor layers is approximately 100 nm to 300 angstroms thick.
7. A multijunction photovoltaic cell as defined in claim 1, wherein the first semiconductor layer comprises InGaAs and the second semiconductor layer comprises GaAsP.
8. A multijunction photovoltaic cell as defined in claim 7, wherein a percentage of indium in each InGaAs layer is in the range of 10 to 30%.
9. A multifunction photovoltaic cell as defined in claim 1, wherein the top subcell comprises InGaP and has a thickness so that it generates approximately 4-5% less current than said first current.
10. A multijunction solar cell comprising:
a semiconductor substrate; and
a sequence of semiconductor layers disposed over the substrate and adapted to form a stack of subcells with the substrate, wherein a middle subcell of the stack comprises a sequence of alternating first and second different semiconductor layers, and wherein an average lattice constant of the sequence of alternating first and second semiconductor layers is approximately equal to a lattice constant of the substrate.
11. The multijunction solar cell of claim 10, wherein the sequence of first and second semiconductor layers form a base layer of the middle subcell.
12. The multijunction solar cell of claim 10, wherein the sequence of first and second semiconductor layers is disposed between a base layer and emitter layer of the middle subcell.
13. The multijunction solar cell of claim 10, wherein the total thickness of the sequence of first and second semiconductor layers is approximately 3 microns.
14. The multifunction solar cell of claim 10, wherein the thickness of each of the first and second semiconductor layers is in the range of 100 to 300 angstroms.
15. A multijunction solar cell comprising:
a semiconductor structure including a sequence of semiconductor layers disposed and adapted to form a vertical stack of solar subcells; and
a plurality of semiconductor layers disposed in a middle subcell in the stack, wherein each alternating layer comprises a first compressively strained semiconductor layer and a second tensionally strained semiconductor layer.
16. The multijunction solar cell of claim 15, wherein the thickness of the layers of the middle solar cell is selected so that photo-generated current of the middle subcell is substantially equal to the photo-generated current density of the lower subcell adjacent to the middle subcell.
17. The multijunction solar cell of claim 15, wherein the semiconductor structure is grown on a semiconductor substrate and the average lattice constant of the plurality of semiconductor layers in the middle cell is approximately equal to the lattice constant of the semiconductor substrate.
18. The multijunction solar cell of claim 15, wherein the average of the strains of the plurality of strained layers is approximately zero.
19. The multifunction solar cell of claim 15, wherein each strained semiconductor layer comprises a III-V semiconductor compound and forms a quantum well.
20. The multifunction solar cell of claim 15, wherein the plurality of semiconductor layers have a total thickness of approximately 3 microns.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A hearing kit for use with a hearing device applying fixed beamforming technology, comprising
a first end portion,
a first microphone disposed at the first end portion,
a second end portion,
a second microphone disposed at the second end portion,
an elongated third portion between the first and second end portions for resting on the user’s neck, adapted to position the first and second microphones on the left and right sides of the user at the same level, wherein the first and second microphones are adapted to face outward toward the same direction in use, and
a processing unit adapted to process signals received from the microphones and transmit processed signals to the hearing device of the user,
whereby the microphones face toward the same direction of the user for receiving the listening sound.
2. The hearing kit as recited in claim 1, wherein the third portion is bended.
3. The hearing kit as recited in claim 1, wherein the third portion is flexible.
4. The hearing kit as recited in claim 1, wherein the third portion is a cord.
5. The hearing kit as recited in claim 1, wherein hearing kit further comprising a wire adapted to transmit the processed signals to the hearing device of the user.
6. The hearing kit as recited in claim 1, wherein the third portion is foldable for superimposing the first end portion with the second end portion.
7. The hearing kit as recited in claim 1, wherein the third portion further comprises
two sub-portions, each sub-portion having a rotatable end, and
a connecting member adapted to connect with the said ends, wherein each said end is rotatable on the connecting member to superimpose the sub-portions.
8. The hearing kit as recited in claim 1, wherein the third portion further comprises a plurality of telescopic sub-portions.
9. The hearing kit as recited in claim 5, further comprises another wire adapted to transmit the processed signals to another hearing device of the user.
10. The hearing kit as recited in claim 1, wherein the connection between the processing unit and the hearing device is wireless.
11. The hearing kit as recited in claim 1, further comprising a connection means for connecting the microphones with the processing unit.
12. The hearing kit as recited in claim 7, wherein the connecting member further comprising a stopper disposed adjacent to the end of the sub-portion to limit the rotation of the sub-portion.
13. A hearing kit for use with a hearing device applying fixed beamforming technology, comprising
a first end portion,
a first microphone disposed at the first end portion,
a second end portion,
a second microphone disposed at the second end portion,
an elongated third portion between the first and second end portions for resting on the user’s neck, bended and adapted to position the first and second microphones on the left and right sides of the user at the same level, wherein the first and second microphones are adapted to face outward toward the same direction in use,
a processing unit adapted to process signals received from the microphones,
a connection means for connecting the microphones with the processing unit, and
a wire adapted to transmit the processed signals to the hearing device of the user,
whereby the microphones face toward the same direction of the user for receiving the listening sound.