CN210015252U - Optical filter - Google Patents
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- CN210015252U CN210015252U CN201920843250.XU CN201920843250U CN210015252U CN 210015252 U CN210015252 U CN 210015252U CN 201920843250 U CN201920843250 U CN 201920843250U CN 210015252 U CN210015252 U CN 210015252U
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Abstract
The application discloses an optical filter. One specific embodiment of the optical filter comprises a substrate and a first film system arranged on the outer side of a first surface of the substrate, wherein the first film system comprises a high-refractive-index film layer, a low-refractive-index film layer and a matching film layer; the material of the matching film layer comprises a nitrogen-doped silicon-germanium mixture, and the chemical formula of the nitrogen-doped silicon-germanium mixture is SixGe1‑xNyWherein x is more than or equal to 0 and less than or equal to 1 and 0<y is less than or equal to 0.1, the refractive index of the high-refractive-index film layer is greater than that of the low-refractive-index film layer within the wavelength range of 780nm to 3000nm, and the refractive index of the matching film layer is not equal to that of the adjacent film layer.
Description
Technical Field
The disclosure relates to the field of optical elements, and more particularly, to a near-infrared filter.
Background
The near-infrared narrowband filter can be applied to a face recognition system, a gesture recognition system, a laser radar, an intelligent household appliance and the like, and when the systems or equipment work, the near-infrared narrowband filter often receives obliquely incident light.
The near-infrared narrowband filter generally comprises a substrate, wherein a multilayer film is plated on two surfaces of the substrate to form a film system, the near-infrared narrowband filter has a passband corresponding to light, most of light corresponding to a passband wave band can pass through the near-infrared narrowband filter, and most of light of a non-passband wave band is cut off. There is a need in the art for an optical filter with superior filtering properties to improve imaging quality.
SUMMERY OF THE UTILITY MODEL
To solve or partially solve the above-mentioned drawbacks of the prior art, embodiments of the present application provide an optical filter and a method of manufacturing the optical filter. Embodiments of the present application also provide optical systems.
The embodiment of the application provides an optical filter, which comprises a substrate and a first film system arranged on the outer side of a first surface of the substrate, wherein the first film system comprises a high-refractive-index film layer, a low-refractive-index film layer and a matching film layer; the material of the matching film layer comprises a nitrogen-doped silicon-germanium mixture, and the chemical formula of the nitrogen-doped silicon-germanium mixture is SixGe1-xNyWherein x is more than or equal to 0 and less than or equal to 1 and 0<y is less than or equal to 0.1, the refractive index of the high-refractive-index film layer is greater than that of the low-refractive-index film layer within the wavelength range of 780nm to 3000nm, and the refractive index of the matching film layer is not equal to that of the adjacent film layer.
In one embodiment, the optical filter has a pass band having a center wavelength shifted by no more than 16nm when an incident angle of light is changed from 0 ° to 30 °, corresponding to a wavelength range of 780nm to 1200 nm.
In one embodiment, the pass band of the filter has a center wavelength of the corresponding p light and a center wavelength of the corresponding s light, and when the incident angle of the light is 30 °, a drift between the center wavelength of the corresponding p light and the center wavelength of the corresponding s light is not more than 5 nm.
In one embodiment, the filter has a passband having an average transmittance of no less than 93%.
In one embodiment, the refractive index of the high refractive index film layer is greater than 3, the refractive index of the low refractive index film layer is less than 3, and the refractive index of the matching film layer is between 1.7 and 4.5 corresponding to a wavelength range of 780nm to 1200 nm.
In one embodiment, the nitrogen-doped SiGe mixture may be further doped with hydrogen, and has a chemical formula of SixGe1- xNy:HzWherein x is more than or equal to 0 and less than or equal to 1 and 0<y is less than or equal to 1, z is less than or equal to 1, and at least one part of the silicon germanium is amorphous hydrogenated nitrogen-doped silicon germanium mixture α -SixGe1-xOy:Hz。
In one embodiment, the nitrogen doped silicon germanium mixture further comprises an auxiliary component comprising one or more of oxygen, boron or phosphorus, wherein the ratio of the number of atoms in each auxiliary component to the number of silicon atoms is less than 10%.
In one embodiment, the material of the high refractive index film layer includes SiwGe1-w:HvWherein w is more than or equal to 0 and less than or equal to 1, and v is more than or equal to 0 and less than or equal to 1.
In one embodiment, the material of the low refractive index film layer comprises SiO2、Si3N4、Ta2O5、Nb2O5、TiO2、Al2O3SiCN, SiC
In one embodiment, the substrate further comprises a second face opposite to the first face, and the optical filter further comprises a second film train disposed outside the second face of the substrate; the second membrane system is a long-wave through membrane system or a wide-band through membrane system, and the first membrane system is a narrow-band through membrane system; the passband of the second film system covers the passband of the first film system.
In one embodiment, the sum of the thickness of the first film system and the thickness of the second film system is less than 12 μm.
In one embodiment, the second membrane system is a long-wave pass membrane system corresponding to a wavelength range of 350nm to 1200nm, the narrow-band pass membrane system has a pass band, the long-wave pass membrane system has a pass band and a cut-off band, and the pass band of the long-wave pass membrane system covers the pass band of the narrow-band pass membrane system; and the cutoff degree of the cutoff band of the long-wave pass membrane system is not lower than the cutoff degree of the corresponding wave band of the narrow-band pass membrane system.
In one embodiment, the second film system is a wide band-pass film system corresponding to a wavelength range of 780nm to 1200nm, the narrow band-pass film system has a pass band, the wide band-pass film system has a pass band, and the pass band of the wide band-pass film system covers the pass band of the narrow band-pass film system; corresponding to the wavelength range less than 780nm, the average cut-off degree of the wide band-pass film system is not lower than that of the narrow band-pass film system.
In one embodiment, the first film system has a structural form in a direction away from the substrate that is one of the following structural forms: (L)3-L1-L3-L2)s-L3-L1；(L1-L3)2-(L2-L3-L1-L3)s-L1-L3；(L1-L3)s–(L2-(L1-L3)p-L1-L2)q-(L1-L3)rL1；(L3-L1)s–(L2-(L1-L3)p-L1-L2)q-(L3-L1)rL3-L1-(L2-(L1-L3)t-L1-L2)n；(L3-L1)s–(L3-L1)rL3-(L2-(L1-L3)p-L1-L2)q-(L3-L1)rL3-(L2-(L1-L3)t-L1-L2)n-(L3-L1)rIn the structural form of the first film system, L1Represents a high refractive index film layer, L3Represents a first low refractive index film layer, L2Represents a matching film layer, p, q, r and s represent the repeated times of structural forms in brackets, and p, q, r and s are integers which are greater than or equal to 0.
In a second aspect, embodiments of the present application provide an optical system, which may include an infrared image sensor and the aforementioned optical filter, where the optical filter is disposed on a photosensitive side of the infrared image sensor.
In the optical filter provided by the embodiment of the present disclosure, the first film system of the optical filter includes a high refractive index film layer, a matching film layer and a low refractive index film layer, and the material of the matching film layer is the nitrogen-doped silicon germanium mixture so as to be suitable for matching the high refractive index film layer or the low refractive index film layer. Specifically, the bonding mode of germanium element (or silicon element) and other elements is changed by doping nitrogen atoms in the silicon-germanium mixture, the mole number of the nitrogen element is less than 10% of the sum of the mole number of the silicon element and the mole number of the germanium element, and different nitrogen doping contents have different influences on the refractive index of the material, and a graph showing the relationship between the refractive index and the nitrogen doping in the following graph is detailed. According to different products or customer optical specification requirements, the nitrogen doping amount is adjusted to further manufacture a suitable medium refractive index material used as a film material of an F-P structure or a film material of a matching layer. Through matching the rete and other retes cooperations, make the optical filter that this application provided when corresponding different angle incident light, the bandwidth change of the passband of optical filter is little. The optical system provided with the optical filter has high signal-to-noise ratio and high data quality, or other parts of the optical system can have higher design margin under the same signal-to-noise ratio requirement.
Drawings
Other features, objects and advantages of the disclosure will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:
FIG. 1 shows a schematic block diagram of an optical filter according to an embodiment of the present application;
FIGS. 2a and 2b show a refractive index profile and an extinction coefficient profile, respectively, of a matching layer according to embodiments of the present application;
FIG. 3 shows a transmittance wavelength curve according to the first embodiment of the present application;
FIG. 4 shows a transmittance wavelength curve according to example two of the present application;
FIG. 5 shows a transmittance wavelength curve according to example three of the present application; and
fig. 6 shows a schematic configuration diagram of an optical system according to an embodiment of the present application.
Detailed Description
For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.
It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first film train discussed below may also be referred to as the second film train without departing from the teachings of the present application. And vice versa.
In the drawings, the thickness, size and shape of the components have been slightly adjusted for convenience of explanation. The figures are purely diagrammatic and not drawn to scale. For example, the thickness of the first film system and the thickness of the second film system are not in proportion in actual production. As used herein, the terms "approximately", "about" and the like are used as table-approximating terms and not as table-degree terms, and are intended to account for inherent deviations in measured or calculated values that would be recognized by one of ordinary skill in the art.
It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.
Unless otherwise defined, all terms (including engineering and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. In addition, unless explicitly defined or contradicted by context, the specific steps included in the methods described herein are not necessarily limited to the order described, but can be performed in any order or in parallel. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
Fig. 1 shows a schematic structural diagram of an optical filter according to an embodiment of the present application. Referring to fig. 1, an optical filter 5 provided in an embodiment of the present application includes: the substrate 51 is a transparent substrate and includes an upper surface and a lower surface opposite to each other, the upper surface is a first surface, the lower surface is a second surface, and the first film system 52 is disposed outside the first surface of the substrate 51. The first film series 52 includes a high refractive index film layer, a low refractive index film layer, and a matching film layer.
In an exemplary embodiment, the substrate 51 has other optical structures, such as a prism, and the light incident surface and the light emitting surface of the substrate 51 can be regarded as a first surface and a second surface, respectively.
In an exemplary embodiment, the material of the matching film layer comprises a hydrogenated nitrogen-doped silicon germanium mixture having a chemical formula of SixGe1-xNyH, wherein x is more than or equal to 0 and less than or equal to 1 and 0<y is less than or equal to 0.1. Illustratively, the nitrogen-doped silicon germanium mixture has the formula SixGe1-xNyIn the formula, x is more than or equal to 0 and less than or equal to 0.5 and 0<y<0.1, e.g. nitrogen-doped SiGe mixture of formula Si0.5Ge0.5N0.05. Illustratively, 0 ≦ x ≦ 0.3, 0<y<0.1, e.g. nitrogen-doped SiGe mixture of formula Si0.1Ge0.9N0.02:H0.7. Illustratively, the nitrogen-doped silicon germanium mixture has the formula SiN0.1:H。
In an exemplary embodiment, the material of at least a portion of the matching film layer is an amorphous nitrogen-doped silicon germanium mixture α -SixGe1-xNy. Illustratively, the volume of the amorphous nitrogen-doped silicon germanium mixture is 20% of the volume of the matching film layer. The matching film layer is formed by molecular layer accumulation, and exemplarily comprises a plurality of amorphous nitrogen-doped silicon germanium mixture layers and a plurality of single-crystal nitrogen-doped silicon germanium mixture layers, wherein the sum of the thicknesses of all the amorphous nitrogen-doped silicon germanium mixture layers and the thickness of the matching film layer is between 16% and 20%. Illustratively, the material of the matching film layer includes one or more of a polycrystalline nitrogen-doped silicon germanium mixture, a microcrystalline nitrogen-doped silicon germanium mixture, and a nanocrystalline nitrogen-doped silicon germanium mixture. The optical constant of the matching film layer is suitable for being accurately set in a large range, the state of P light and s light passing through the matching film layer can be kept stable under a complex working environment, and the drift between the center wavelength of the P light and the center wavelength of the s light of the first film system is small.
In an exemplary embodiment, the refractive index of the high refractive index film layer is greater than the refractive index of the low refractive index film layer in the wavelength range of 780nm to 1200nm, and the refractive index of the matching film layer is not equal to the refractive index of its adjacent film layer.
The optical filter provided by the embodiment of the application can accurately set the optical constant to realize the special specified optical characteristics in a wider range. Such as a narrowband filter of a particular bandwidth. The optical filter provided by the application can be used for realizing the passing of a specific optical band gap in a photovoltaic cell, or realizing high absorption or high cut-off of light in a specific waveband.
In the exemplary embodiment, the optical filter 5 has a pass band corresponding to a wavelength range of 780nm to 1200nm, and the shift amount of the center wavelength of the pass band is not more than 16nm when the incident angle of light is changed from 0 ° to 30 °. Illustratively, the shift in the center wavelength of the pass band is no greater than 13nm, such as no greater than 11nm, when the angle of incidence of the light is changed from 0 to 30. The bandwidth of the passband can be increased by controlling the drift amount of the center wavelength, and the signal-to-noise ratio can be increased.
In an exemplary embodiment, the pass band of the optical filter 5 has a center wavelength of the corresponding p light and a center wavelength of the corresponding s light, and when the incident angle of the light is 30 °, the drift between the center wavelength of the corresponding p light and the center wavelength of the corresponding s light is not more than 5 nm. Illustratively, the drift between the p-light center wavelength and the s-light center wavelength is no greater than 4.2 nm. The drift amount between the p-light center wavelength and the s-light center wavelength is controlled, so that the bandwidth of the passband can be improved, and equipment and circuits using the optical filter have higher design margins.
In an exemplary embodiment, the average transmittance of the pass band of the optical filter 5 is not less than 93%. Illustratively, the average transmittance of the pass band of the optical filter 5 is not less than 94%. The average transmittance of the passband is controlled so that the intensity of light rays in a band corresponding to the passband among the light rays passing through the optical filter 5 is high, and the signal-to-noise ratio can also be improved.
In an exemplary embodiment, the refractive index of the high refractive index film layer is greater than 3, the refractive index of the low refractive index film layer is less than 3, and the refractive index of the matching film layer is between 1.7 and 4.5 in a wavelength range of 780nm to 1200 nm. Illustratively, the high index film layer has a refractive index greater than 4, the matching layer has a refractive index between 3 and 4.5, and the low index film layer has a refractive index less than 3. Illustratively, the high refractive index film layer has a refractive index of 4.5, the low refractive index film layer has a refractive index of 2.8, and the plurality of matching film layers have different refractive indices, for example, refractive indices of 3, 3.5, and 4, respectively. The refractive index of the matching film layer, the refractive index of the high refractive index film layer, and the refractive index of the low refractive index film layer are controlled to control the state of light passing through each film layer, for example, the difference between the optical characteristics of p light and s light is small after passing through each film layer, so as to realize the specific optical characteristics of the first film system 52.
In an exemplary embodiment, the matching film layer has a refractive index less than that of the high refractive index film layer and greater than that of the low refractive index film layer.
In an exemplary embodiment, the nitrogen-doped silicon germanium mixture is a hydrogenated nitrogen-doped silicon germanium mixture having the formula SixGe1-xNy:HzWherein x is more than or equal to 0 and less than or equal to 1 and 0<y is less than or equal to 0.1, and z is less than or equal to 1. Exemplary, SixGe1-xNy:HzIn the formula, x is more than or equal to 0 and less than or equal to 0.5 and 0<y<0.1, z is less than or equal to 1; for example, hydrogenated oxygen-doped silicon germanium based materials having the formula Si0.5Ge0.5N0.05:H0.5。
In an exemplary embodiment, the hydrogenated oxygen-doped silicon germanium-based material has the formula SixGe1-xNy:HzIn the formula, x is more than or equal to 0 and less than or equal to 0.3 and 0<y<0.1，0.8<z is less than or equal to 1; illustratively, the hydrogenated oxygen-doped silicon germanium-based material has the formula Si0.1Ge0.9N0.02:H0.7. An exemplary hydrogenated oxygen-doped silicon germanium-based material has the formula SiN0.1H, a hydrogenated oxygen-doped silicon-based material.
In an exemplary embodiment, at least a portion of the hydrogenated nitrogen-doped silicon germanium mixture is an amorphous hydrogenated nitrogen-doped silicon germanium mixture α -SixGe1-xNy:Hz。
In an exemplary embodiment, the nitrogen-doped silicon germanium mixture further includes an auxiliary component including one or more of nitrogen, boron, or phosphorus, the ratio of the number of atoms of the auxiliary component to the number of atoms of silicon being less than 0.1.
Referring to fig. 2, the conditional expression is satisfied: a is less than 0.1b, a smaller amount of oxygen element and auxiliary components can be used, and the adjustment refractive index in a larger range can be achieved by changing in a narrower range. The corresponding matching film layer has stable physical and chemical properties and can have specially specified optical characteristics in a larger range.
In an exemplary embodiment, the material of the high refractive index film layer includes SiwGe1-w:HvWherein w is more than or equal to 0 and less than or equal to 1, and v is more than or equal to 0 and less than or equal to 1. Illustratively, w is 0.2 or 0.37.
In an exemplary embodiment, the material of the low refractive index film layer includes SiO2、Si3N4、Ta2O5、Nb2O5、TiO2、Al2O3SiCN and SiC.
In an exemplary embodiment, the material of the substrate includes glass. Specifically, D263T, AF32, Eagle XG, H-ZPK5, H-ZPK7 and the like can be mentioned.
In an exemplary embodiment, the substrate further includes a second face opposite to the first face, and the optical filter further includes a second film train disposed outside the second face of the substrate; the second membrane system is a long-wave through membrane system or a wide-band through membrane system, and the first membrane system is a narrow-band through membrane system; the pass band of the second film series covers the pass band of the first film series. By arranging the second film system, the optical filter 5 can have better anti-reflection and cut-off effects on light, so that the light penetrating through the optical filter 5 has higher signal-to-noise ratio.
In an exemplary embodiment, the sum of the thickness of the first film system and the thickness of the second film system is less than 15 μm, for example, less than 12 μm. The thickness of the two film systems is controlled to make the offset between the central wavelength corresponding to p light and the central wavelength corresponding to s light small, and the production cost can be reduced.
In an exemplary embodiment, the second membrane system is a long-wave pass membrane system corresponding to a wavelength range of 350nm to 1200nm, the narrow-wave pass membrane system has a pass band, the long-wave pass membrane system has a pass band and a cut-off band, and the pass band of the long-wave pass membrane system covers the pass band of the narrow-wave pass membrane system; the cut-off degree of the cut-off band of the long-wave pass membrane system is not lower than the cut-off degree of the corresponding wave band of the narrow-band pass membrane system. By controlling the cutoff of the long-wave pass film system, the cutoff of the filter 5 can be improved, and the transmittance of light in the corresponding wavelength band can be reduced, so that the noise signal in the image formed by the light passing through the filter 5 is weak.
In an exemplary embodiment, the second membrane system is a wide band-pass membrane system corresponding to a wavelength range of 780nm to 1200nm, the narrow band-pass membrane system has a pass band, the wide band-pass membrane system has a pass band, and the pass band of the wide band-pass membrane system covers the pass band of the narrow band-pass membrane system; the average cut-off degree of the wide band-pass membrane system is not lower than that of the narrow band-pass membrane system corresponding to the wavelength range less than 780 nm. By controlling the cutoff of the broadband pass system, the cutoff of the filter 5 can be improved, and the transmittance of light in the corresponding wavelength band can be reduced, so that the noise signal in the image formed by the light passing through the filter 5 is weak.
In an exemplary embodiment, the first film system has a structural form in a direction away from the substrate of one of the following structural forms: (L)3-L1-L3-L2)s-L3-L1；(L1-L3)2-(L2-L3-L1-L3)s-L1-L3；(L1-L3)s–(L2-(L1-L3)p-L1-L2)q-(L1-L3)rL1；(L3-L1)s–(L2-(L1-L3)p-L1-L2)q-(L3-L1)rL3-L1-(L2-(L1-L3)t-L1-L2)n；(L3-L1)s–(L3-L1)rL3-(L2-(L1-L3)p-L1-L2)q-(L3-L1)rL3-(L2-(L1-L3)t-L1-L2)n-(L3-L1)rIn the structural form of the first film system, L1Represents a high refractive index film layer, L3Represents a first low refractive index film layer, L2Represents a matching film layer, p, q,r and s represent the number of times the structural form in parentheses is repeated, and p, q, r and s are integers greater than or equal to 0.
Three embodiments provided by the present application are detailed below with reference to fig. 3 to 5.
Example one
The filter 5 of the present embodiment includes a substrate 51, a first film system 52 formed by sputter coating is disposed on an outer side of a first surface of the substrate 51, and the first film system 52 may include the narrow band-pass film system provided in table 1, where the layer 1 is a film layer closest to the substrate 51; the second side of the substrate 51 is provided with a second film system 53 formed by sputter coating, and the second film system 53 may include the long-wave pass film system provided in table 2, wherein the layer 1 is the film layer closest to the substrate 51. Referring to fig. 3, when the incident angle of the light is changed from 0 ° to 30 °, the shift amount of the center wavelength of the pass band of the filter 5 is not more than 12 nm.
This application table 1 provides a narrow band-pass membrane system, and the rete in table 1 is the same to the material of same row. In table 1, reference numerals 1 to 22 denote the order in which the film layers of the first film train 52 are stacked in the direction away from the substrate 51. For example, "1" refers to layer 1 of the film layer described above that is closest to the substrate 51.
Table 1: film structure of narrow band pass film system (film thickness unit: nm)
In the narrow band-pass film system, the high-refractive-index film layer is made of α -Si: H, and the low-refractive-index film layer is made of SiO2The matching film layer is made of α -SiNy Hz.
Table 2 provides a long-wave pass membrane system, and the materials of the membrane layers in the same row in table 2 are the same. In table 2, reference numerals 1 to 27 denote the order in which the respective film layers of the second film train 53 are stacked in the direction away from the substrate 51. For example, "1" refers to layer 1 of the film layer described above that is closest to the substrate 51.
Table 2: film structure of long-wave through film system (film thickness unit: nm)
The optical filter 5 has a small thickness, is easy to manufacture, has a high pass band transmittance, and has a high intensity of light passing through the optical filter 5.
Example two
The filter 5 provided in this embodiment includes a substrate 51, a first film system 52 formed by sputter coating is disposed on an outer side of a first surface of the substrate 51, a second film system 53 formed by evaporation coating is disposed on an outer side of a second surface of the substrate 51, and the first film system 52 may include the narrow band-pass film system provided in table 3, where the layer 1 is a film layer closest to the substrate 51; the second film train 53 may comprise the long wave pass film train provided in Table 4, wherein layer 1 is the film layer closest to the substrate 51. Referring to fig. 4, when the incident angle of the light is changed from 0 ° to 30 °, the shift amount of the center wavelength of the pass band of the filter 5 is smaller than 13 nm.
Table 3 provides a narrow band-pass film train, and in table 3, reference numerals 1-23 indicate the order in which the film layers of the first film train 52 are stacked in a direction away from the substrate 51. For example, "1" refers to layer 1 of the film layer described above that is closest to the substrate 51.
Table 3: film structure of narrow band pass film system (film thickness unit: nm)
In the narrow band-pass film system, the high-refractive-index film layer is made of α -Si: H, and the low-refractive-index film layer is made of SiO2The matching film layer is made of α -GeNy:Hz. The 11 th layer is a matching film layer which is arranged with the film layer approximately according to the 11 th layer.
Table 4 provides a long-wave pass membrane system, and the materials of the membrane layers in the same row in table 4 are the same. In table 4, reference numerals 1 to 47 denote the order in which the respective film layers of the second film train 53 are stacked in the direction away from the substrate 51. For example, "1" refers to layer 1 of the film layer described above that is closest to the substrate 51.
Table 4: film structure of long-wave through film system (film thickness unit: nm)
| Material | SiO2 | Si:H | SiO2 | Si:H | SiO2 | Si: |
| Film layer | ||||||
| 1 | 2 | 3 | 4 | 5 | 6 | |
| Film thickness | 134.4 | 72.6 | 90.3 | 67.45 | 120.98 | 77.91 |
| Film layer | 7 | 8 | 9 | 10 | 11 | 12 |
| Film thickness | 136 | 83.4 | 97.5 | 70.9 | 270.45 | 75.64 |
| Film layer | 13 | 14 | 15 | 16 | 17 | 18 |
| Film thickness | 111.7 | 67.6 | 101.7 | 197.77 | 116.51 | 74.86 |
| Film layer | 19 | 20 | 21 | 22 | 23 | 24 |
| Film thickness | 118.7 | 75.8 | 120.1 | 76.06 | 103.28 | 42.14 |
| Film layer | 25 | 26 | 27 | 28 | 29 | 30 |
| Film thickness | 133.6 | 83.1 | 131.4 | 83.54 | 133.68 | 85.88 |
| Film layer | 31 | 32 | 33 | 34 | 35 | 36 |
| Film thickness | 133.1 | 84.1 | 135.3 | 84.91 | 135.75 | 84.61 |
| Film layer | 37 | 38 | 39 | 40 | 41 | 42 |
| Film thickness | 87.1 | 75.6 | 124.5 | 80.29 | 129.71 | 82.58 |
| Film layer | 43 | 44 | 45 | 46 | 47 | - |
| Film thickness | 136.4 | 87.5 | 130.1 | 77.82 | 103.24 | - |
The filter 5 has a narrow pass band width, a small offset between the p-light center wavelength and the s-light center wavelength, and a high cut-off degree in a cut-off region.
EXAMPLE III
The filter 5 provided in this embodiment includes a substrate 51, a first film system 52 formed by sputter-coating is disposed on an outer side of a first surface of the substrate 51, and a second film system 53 formed by sputter-coating is disposed on an outer side of a second surface of the substrate 51, where the first film system 52 may include the narrow band-pass film system provided in table 5, where the layer 1 is a film layer closest to the substrate 51; the second film train 53 can comprise the wide band pass film train provided in table 6, wherein layer 1 is the film layer closest to the substrate 51. Referring to fig. 5, when the incident angle of the light is changed from 0 ° to 30 °, the shift amount of the center wavelength of the pass band of the filter 5 is smaller than 11 nm.
Table 5 provides a narrow band-pass film train, and in table 5, numbers 1-30 indicate the order in which the film layers of the first film train 52 are stacked in a direction away from the substrate 51. For example, "1" refers to layer 1 of the film layer described above that is closest to the substrate 51.
Table 5: film structure of narrow band pass film system (film thickness unit: nm)
| Material | SiwGe1-w:Hz | SiO2 | SiwGe1-w:Hv | SiO2 |
| Film layer | 1 | 2 | 3 | 4 |
| Film thickness | 251.17 | 546.59 | 259.12 | 78.57 |
| Material | α-SiNy:Hz | SiO2 | SiwGe1-w:Hv | SiO2 |
| Film layer | 5 | 6 | 7 | 8 |
| Film thickness | 45.8 | 260.65 | 129.01 | 79.08 |
| Film layer | 9 | 10 | 11 | 12 |
| Film thickness | 405.59 | 176.63 | 512.64 | 199.39 |
| Film layer | 13 | 14 | 15 | 16 |
| Film thickness | 51.95 | 129.4 | 529.57 | 134.55 |
| Film layer | 17 | 18 | 19 | 20 |
| Film thickness | 83.33 | 92.16 | 516.39 | 231.92 |
| Film layer | 21 | 22 | 23 | 24 |
| Film thickness | 380.86 | 130.42 | 137.36 | 136.26 |
| Film layer | 25 | 26 | 27 | 28 |
| Film thickness | 52.8 | 63.74 | 259.88 | 559.97 |
| Material | SiwGe1-w:Hv | SiO2 | - | - |
| Film layer | 29 | 30 | - | - |
| Film thickness | 240.7 | 126.8 | - | - |
In the narrow band-pass film system, the material of the high-refractive-index film layer is SiwGe1-w:HzThe material of the low refractive index film layer is SiO2The matching film layer is made of α -SiNy (Hz.) layer 5-layer 28 structureIs of the form (L)2-L3-L1-L3)6。
Table 6 provides a wide band pass film system, with numbers 1-35 indicating the order in which the film layers of the second film system 53 are stacked in a direction away from the substrate 51. For example, "1" refers to layer 1 of the film layer described above that is closest to the substrate 51.
Table 6: film structure of wide band through film system (film thickness unit: nm)
The filter 5 has narrow passband width, small drift amount of the center wavelength of the passband, and high passband transmittance.
However, it is understood by those skilled in the art that the above embodiments are only examples, the first film train 52 and the second film train 53 of the optical filter 5 may have other film layer structures, and the first film train 52 or the second film train 53 of each embodiment may also be applied to other exemplary embodiments. And other transparent layers, such as air cavity, etc., can be disposed outside the first and second surfaces of the filter 5.
The embodiment of the present application also provides a method for manufacturing an optical filter, which includes the following steps:
placing a piece to be plated and a target material at corresponding positions in a deposition chamber, wherein when a layer to be plated is a matching film layer, the material of the target material comprises a silicon component and a germanium component, vacuumizing the deposition chamber, and keeping the vacuum degree in the deposition chamber at a preset value;
introducing argon into the deposition chamber, wherein the flow of the argon is a preset value;
introducing hydrogen and oxygen into the deposition chamber, wherein the flow of the hydrogen is a preset value, and the flow of the oxygen is less than 60 sccm; and forming a film layer on the workpiece to be plated, wherein the material of the film layer comprises the nitrogen-doped silicon germanium mixture.
In an exemplary embodiment, the degree of vacuum within the deposition chamber is less than 5 × 10-5torr; the flow rate of the argon is between 10sccm and 300 sccm; the flow rate of the hydrogen gas is less than 80 sccm.
The embodiment of the present application further provides an optical system, which includes an infrared image sensor and the aforementioned optical filter 5, where the optical filter 5 is disposed on a photosensitive side of the infrared image sensor.
Referring to fig. 6, the optical system includes an Infrared (IR) light source 2, a first lens assembly 3, a second lens assembly 4, a filter 5 and a three-dimensional sensor 6. Light emitted by the infrared light source 2 irradiates the surface of the object 1 to be measured through the first lens assembly 3, light reflected by the surface of the object 1 to be measured irradiates the optical filter 5 through the second lens assembly 4, ambient light is cut off by the optical filter 5, and infrared rays or part of red light irradiates the photosensitive side of the three-dimensional sensor 6 through the optical filter 5 to form image data for processing. The optical filter 5 has a lower central wavelength offset corresponding to the inclined light rays in different directions, the signal-to-noise ratio of the transmitted infrared rays is high, and the quality of the formed image is good.
The above description is only a preferred embodiment of the present application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of protection covered by the present application is not limited to the embodiments with a specific combination of the features described above, but also covers other embodiments with any combination of the features described above or their equivalents without departing from the technical idea described above. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (10)
1. The optical filter is characterized by comprising a substrate and a first film system arranged on the outer side of a first surface of the substrate, wherein the first film system comprises a high-refractive-index film layer, a low-refractive-index film layer and a matching film layer;
the material of the matching film layer comprises a nitrogen-doped silicon-germanium mixture,
in the wavelength range of 780nm to 3000nm, the refractive index of the high-refractive-index film layer is greater than that of the low-refractive-index film layer, and the refractive index of the matching film layer is not equal to that of the adjacent film layer.
2. The optical filter according to claim 1, wherein the optical filter has a pass band whose center wavelength is not shifted by more than 16nm when an incident angle of light is changed from 0 ° to 30 °, corresponding to a wavelength range of 780nm to 1200 nm.
3. The optical filter according to claim 2, wherein the pass band of the optical filter has a center wavelength of the corresponding p light and a center wavelength of the corresponding s light, and when the incident angle of the light is 30 °, a drift between the center wavelength of the corresponding p light and the center wavelength of the corresponding s light is not more than 5 nm.
4. An optical filter as defined in claim 2, wherein the average transmittance of the pass band of the optical filter is not less than 93%.
5. The optical filter of claim 1, wherein the refractive index of the high refractive index film layer is greater than 3, the refractive index of the low refractive index film layer is less than 3, and the refractive index of the matching film layer is between 1.7 and 4.5 corresponding to a wavelength ranging from 780nm to 1200 nm.
6. A filter according to claim 1, wherein the substrate further comprises a second face opposite to the first face, and the filter further comprises a second film train disposed outside the second face of the substrate;
the second membrane system is a long-wave through membrane system or a wide-band through membrane system, and the first membrane system is a narrow-band through membrane system; the passband of the second film system covers the passband of the first film system.
7. The filter according to claim 6, wherein the sum of the thickness of the first film series and the thickness of the second film series is less than 12 μm.
8. The optical filter according to claim 6, wherein the second film system is a long-pass film system corresponding to a wavelength range of 350nm to 1200nm, the narrow-pass film system has a pass band, the long-pass film system has a pass band and a stop band, and the pass band of the long-pass film system covers the pass band of the narrow-pass film system;
and the cutoff degree of the cutoff band of the long-wave pass membrane system is not lower than the cutoff degree of the corresponding wave band of the narrow-band pass membrane system.
9. The filter of claim 6, wherein the second film system is a wide band-pass film system corresponding to a wavelength range of 780nm to 1200nm, the narrow band-pass film system has a pass band, the wide band-pass film system has a pass band, and the pass band of the wide band-pass film system covers the pass band of the narrow band-pass film system;
corresponding to the wavelength range less than 780nm, the average cut-off degree of the wide band-pass film system is not lower than that of the narrow band-pass film system.
10. A filter according to claim 6, wherein the first film stack has a structural form in a direction away from the substrate of one of:
(L3-L1-L3-L2)s-L3-L1；
(L1-L3)2-(L2-L3-L1-L3)s-L1-L3；
(L1-L3)s–(L2-(L1-L3)p-L1-L2)q-(L1-L3)rL1；
(L3-L1)s–(L2-(L1-L3)p-L1-L2)q-(L3-L1)rL3-L1-(L2-(L1-L3)t-L1-L2)n；
(L3-L1)s–(L3-L1)rL3-(L2-(L1-L3)p-L1-L2)q-(L3-L1)rL3-(L2-(L1-L3)t-L1-L2)n-(L3-L1)r，
in the structural form of the first film system, L1Represents a high refractive index film layer, L3Represents a first low refractive index film layer, L2Represents a matching film layer, p, q, r and s represent the repeated times of structural forms in brackets, and p, q, r and s are integers which are greater than or equal to 0.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110109210A (en) * | 2019-06-05 | 2019-08-09 | 信阳舜宇光学有限公司 | Optical filter |
| CN113777686A (en) * | 2021-08-20 | 2021-12-10 | 晋中学院 | Broadband all-dielectric low-emissivity film |
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2019
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110109210A (en) * | 2019-06-05 | 2019-08-09 | 信阳舜宇光学有限公司 | Optical filter |
| WO2020244223A1 (en) * | 2019-06-05 | 2020-12-10 | 信阳舜宇光学有限公司 | Optical filter plate |
| CN110109210B (en) * | 2019-06-05 | 2024-06-18 | 信阳舜宇光学有限公司 | Optical filter |
| CN113777686A (en) * | 2021-08-20 | 2021-12-10 | 晋中学院 | Broadband all-dielectric low-emissivity film |
| CN113777686B (en) * | 2021-08-20 | 2024-03-19 | 晋中学院 | Broadband all-dielectric low-emissivity film |
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