Method of manufacturing a spectral filter for green and longer wavelengths
First Claim
1. A method of making a spectral filter comprising:
- providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, and etching the substrate wafer beginning at said start points to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth.
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Accused Products
Abstract
A method of manufacture for optical spectral filters with omnidirectional properties in the visible, near IR, mid IR and/or far IR (infrared) spectral ranges is based on the formation of large arrays of coherently modulated waveguides by electrochemical etching of a semiconductor wafer to form a pore array. Further processing of said porous semiconductor wafer optimizes the filtering properties of such a material. The method of filter manufacturing is large scale compatible and economically favorable. The resulting exemplary non-limiting illustrative filters are stable, do not degrade over time, do not exhibit material delamination problems and offer superior transmittance for use as bandpass, band blocking and narrow-bandpass filters. Such filters are useful for a wide variety of applications including but not limited to spectroscopy, optical communications, astronomy and sensing.
53 Citations
50 Claims
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1. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, and etching the substrate wafer beginning at said start points to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, removing at least one un-etched part of the substrate wafer, and coating the pore walls by at least one layer of substantially transparent material.
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44. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, removing at least one un-etched part of the substrate wafer, coating the pore walls by at least one layer of substantially transparent material, and coating the pore walls at least partially by at least one layer of absorptive or reflective material.
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45. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, removing at least one un-etched part of the substrate wafer, coating the pore walls by at least one layer of substantially transparent material, coating the pore walls at least partially by at least one layer of absorptive or reflective material, and sealing said spectral filter with two flat plates of material that is transparent within the transparency range of said spectral filter.
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46. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, coating the pore walls by at least one layer of substantially transparent material, coating the pore walls at least partially by at least one layer of absorptive or reflective material, removing at least one un-etched part of the substrate wafer, and sealing said spectral filter with two flat plates of material that is transparent within the transparency range of said spectral filter.
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47. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, coating the pore walls by at least one layer of substantially transparent material, filling the pores with at least one partially by at least one layer transparent material the refractive index of which is higher than that of the first layer of transparent material coating the pore walls, removing at least one un-etched part of the substrate wafer, and sealing said spectral filter with two flat plates of material that is transparent within the transparency range of said spectral filter.
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48. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, removing at least one un-etched part of the substrate wafer coating the pore walls by at least one layer of substantially transparent material, filling the pores with at least one partially by at least one layer transparent material the refractive index of which is higher than that of the first layer of transparent material coating the pore walls, and sealing said spectral filter with two flat plates of material that is transparent within the transparency range of said spectral filter.
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49. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, removing at least one un-etched part of the substrate wafer, thermally oxidizing said structured wafer, coating the pore walls by at least one layer of substantially transparent material, filling the pores with at least one partially by at least one layer transparent material the refractive index of which is higher than that of the first layer of transparent material coating the pore walls, and sealing said spectral filter with two flat plates of material that is transparent within the transparency range of said spectral filter.
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50. A method of making a spectral filter comprising:
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providing a substrate wafer of single-crystal semiconductor having a first surface and a second surface, providing etching start points at a first surface of said semiconductor wafer, etching the substrate wafer to produce a structured layer having pores with controlled depths defined at least partially therethrough, said pores having coherently modulated cross-sections at least over the part of said depth, removing at least one un-etched part of the substrate wafer, thermally oxidizing said structured wafer, coating the pore walls by at least one layer of substantially transparent material, the refractive index of which is lower than that of the semiconductor oxide, and sealing said spectral filter with two flat plates of material that is transparent within the transparency range of said spectral filter.
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Specification