Stepped structure optical filter

Abstract

The filter may include a substrate. The filter may include a stepped medium disposed on the substrate. The filter may include a first mirror disposed on the stepped medium. The first mirror may form a stepped mirror surface. Each step of the stepped mirror surface may correspond to one of a set of channels in the filter. The optical filter may include spacers disposed on the stepped mirror surface. The optical filter may include a second mirror disposed on the other surface of the spacers.

Description

[Technical Field]

[0001] This invention relates to stepped structure optical filters. [Previous Technology]

[0002] A light emitter can emit light that is directed toward an object. For example, in a gesture recognition system, a light emitter can emit near-infrared light toward a user, and the near-infrared light can be reflected from the user toward a light receiver. In this case, the light receiver can capture information about the near-infrared light, and this information can be used to recognize the gesture being performed by the user. In another example, information about visible light, such as information about different wavelengths of visible light, can be captured to image an object.

[0003] However, ambient light may be introduced along with the wavelength of interest during the propagation of light toward the target and / or during the reflection of light from the target toward the light receiver. For example, while the light receiver will receive near-infrared light reflected from the target, it may also receive visible light (e.g., from another light source, such as a light bulb or the sun). Therefore, the light receiver may be optically coupled to an optical filter, such as a bandpass filter, to filter the ambient light and allow one or more wavelengths of light to pass toward the light receiver. Alternatively or optionally, when sensing of multiple wavelengths of light is performed, a filter may be provided to ensure that each wavelength of light is directed to a different sensor.

[0004] A multispectral sensor device, which can be a light receiver, can be used to capture information about light of multiple wavelengths. The multispectral sensor device may include a set of sensor elements (e.g., light sensors, spectral sensors, and / or image sensors) that capture information and are coupled to a multispectral filter. For example, an array of sensor elements can be used to capture information associated with multiple frequencies, and the multispectral filter can direct light associated with different frequencies to each sensor element. In some cases, a single binary multispectral filter can be arranged to cover each sensor element in the array of sensor elements and can form a set of channels for the array of sensor elements. [Summary of the Invention]

[0005] According to some possible embodiments, the filter may include a substrate. The filter may include a stepped medium disposed on the substrate. The filter may include a first mirror disposed on the stepped medium. The first mirror may form a stepped mirror surface. Each step of the stepped mirror surface may correspond to one of a set of channels of the filter. The filter may include spacers disposed on the stepped mirror surface. The filter may include a second mirror disposed on another surface of the spacers.

[0006] According to some possible implementations, the system may include a sensor element array comprising a plurality of sensor elements associated with a plurality of channels. The system may include a variable spacer filter. The variable spacer filter may include a first substrate. The variable spacer filter may include a stepped medium disposed on the first substrate. The variable spacer filter may include a first mirror disposed on the stepped medium. The first mirror may form a stepped mirror surface. Each step of the stepped mirror surface may correspond to one of a set of channels of the filter. The variable spacer filter may include a second mirror disposed on a second substrate and alignable with the first mirror. A cavity may separate the first mirror and the second mirror. The second mirror may be translationally movable relative to the first mirror such that the spacing between the first mirror and the second mirror is variable.

[0007] According to some possible embodiments, the multichannel filter may include a dielectric to form a stepped structure. The multichannel filter may include a first mirror disposed on the stepped structure to form a stepped mirror structure. Each step of the stepped mirror structure may form a wavelength channel of the multichannel filter. The multichannel filter may include a spacer disposed on the first mirror. A first surface of the spacer may be disposed against the first mirror to form a stepped surface, and a second surface of the spacer may be opposite the first mirror to form a flat surface. The multichannel filter may include a second mirror disposed on the second surface of the spacer to form a plane mirror of the multichannel filter.

Implementation Method

[0014] The following detailed description of exemplary embodiments is with reference to the accompanying drawings. The same element symbols in different drawings may identify the same or similar elements.

[0015] Sensing elements (e.g., light sensors) can be incorporated into a light sensing device to obtain information (e.g., spectral data) about a set of electromagnetic frequencies. For example, a light sensing device may include an image sensor, a multispectral sensor, etc., capable of performing sensor measurements of light. The light sensing device may utilize one or more sensing technologies, such as complementary metal-oxide-semiconductor (CMOS) technology, charge-coupled device (CCD) technology, etc. A light sensing device may include multiple sensing elements (e.g., an array of sensing elements), each configured to obtain information about different frequencies of light.

[0016] The sensor element can be associated with a filter that filters the light directed toward the sensor element. For example, the sensor element can be aligned with a linear variable filter (LVF), a circular variable filter (CVF), a Fabry-Perot filter, etc., so that a portion of the light directed toward the sensor element is filtered. For a binary filter structure, such as a Fabry-Perot filter, spacers can be positioned between the reflectors (e.g., mirrors) of the binary filter structure. The configuration of the refractive index, thickness, etc., of the reflector layers, spacer layers, etc., allows the binary filter structure to form a set of channels. A channel can be a portion of the sensor elements of the filter that guides light of a specific wavelength range to the sensor element array. In this way, the sensor element array can obtain information about light of multiple different wavelengths.

[0017] However, a fixed set of channels configured at least in part based on a selected refractive index, spacer thickness, and / or the like can limit the sensor element array to performing measurements on a fixed set of wavelengths. Therefore, in order to ensure that a binary multispectral filter, which may also be referred to as a multichannel filter, is configured to capture light of any wavelength of interest, the binary multispectral filter can be designed to have a greater than threshold number of channels, and the sensor element array can accordingly include a greater than threshold number of sensor elements. This can result in excessively large size and / or excessively high cost to ensure flexibility when using a binary multispectral filter.

[0018] Furthermore, some binary multispectral filters use different spacer thicknesses to form different channels in different wavelength ranges. For these binary multispectral filters, different spacer thicknesses can be formed by depositing multiple layers of spacer material on top of a first plane mirror directly deposited on a substrate. In this case, the multiple layers of spacer material are deposited to form a stepped structure of spacers, and a second mirror is deposited on the stepped structure of the spacers. However, depositing multiple layers of spacer material can lead to defects that may degrade the optical performance of the binary multispectral filter. For example, when silicon hydride is used as the spacer material, the surface of each layer of silicon hydride may be partially oxidized to silicon dioxide between the layers, which may result in reduced transmittance, increased angular offset, and / or similar issues.

[0019] Some embodiments described herein provide multispectral filter arrays with improved spacers. For example, a binary multispectral filter may include: a stepped medium disposed between a substrate and a first mirror, such that the first mirror has a stepped surface; a monolithic spacer disposed on the stepped surface of the mirror; and a second mirror disposed on a flat surface of the monolithic spacer. In this case, by constructing the stepped structure by forming the spacer in a single process rather than depositing multiple spacer layers, defects such as surface oxidation can be avoided, thereby improving optical performance. For example, the monolithic spacer can achieve improved transmittance, reduced angular offset, and / or the like.

[0020] Furthermore, some embodiments described herein allow the second mirror to be movable relative to the first mirror, rather than being directly disposed on the spacer and in a fixed position. For example, the second mirror may be translational relative to the first mirror (i.e., either the first or second mirror may be movable, or both the first and second mirrors may be movable), thereby allowing the gap formed by the spacer between the first and second mirrors to change in thickness as the second mirror is translated. In this way, the wavelength range of a set of channels can be dynamically reconfigurable, thereby increasing the number of spectral bands that can be captured by sensor elements aligned with that set of channels. Furthermore, in this way, the number of channels covering a specific spectral range in a multispectral filter can be reduced relative to a multispectral filter with a fixed gap between the mirrors, thereby achieving reduced size, lower cost, and / or the like.

[0021] FIG1 is a diagram of an example embodiment of the multispectral filter 100 described herein. As shown in FIG1, the multispectral filter 100 (e.g., a binary structure optical filter array) may include a substrate 110, a medium 120, a first mirror 130-1, a second mirror 130-2, and a spacer 140.

[0022] In some embodiments, substrate 110 may be associated with a photosensor device. For example, substrate 110 may include an array of sensor elements to capture information (e.g., spectral data). Alternatively or additionally, substrate 110 may not include sensor elements, and multispectral filter 100 may be aligned with sensor elements disposed on another substrate. Alternatively or additionally, multispectral filter 100 may be designed without substrate 110. For example, multispectral filter 100 may be located in free space, may be disposed on a substrate of a photosensor device that is not part of multispectral filter 100, and / or similar arrangements.

[0023] In some embodiments, the multispectral filter 100 may be associated with a specific spectral range. For example, the multispectral filter 100 may be associated with multiple channels in the visible spectral range, the near-infrared (NIR) spectral range, the mid-infrared (MIR) spectral range, and / or the like. In this case, the multispectral filter 100 may be associated with spectral ranges between about 300 nm and 2500 nm, between 360 nm and 2500 nm, between about 600 nm and about 2000 nm, between about 350 nm and about 750 nm, between 380 nm and about 780 nm, between about 750 nm and about 1500 nm, between 750 nm and about 1100 nm, between 900 nm and about 2500 nm, between about 900 nm and about 1700 nm, between about 900 nm and about 1500 nm, and / or the like. In some implementations, the multispectral filter 100 may include a threshold number of channels, such as 8 channels, 16 channels, 32 channels, 64 channels, 128 channels, 256 channels and / or the like.

[0024] As further shown in FIG. 1, the medium 120 may be associated with a stepped structure that can form a set of channels of the multispectral filter 100. For example, as described in more detail herein, photolithography can be used to form the stepped structure to form the medium 120. In some embodiments, as shown, the medium 120 may be stepped along a single axis (i.e., stepped in one dimension). For example, the medium 120 may be stepped to form a set of eight different channels extending along a single axis. In some embodiments, the medium 120 may be stepped along multiple axes (i.e., stepped in two dimensions). For example, the medium 120 may be stepped perpendicular to a single axis to form a total of 64 different channels. In some embodiments, the medium 120 may include one or more repeating channels. For example, as shown, channels 7 formed by the medium 120 may be arranged at the edges of the multispectral filter 100, which may provide structural stability to the multispectral filter 100. In some embodiments, the medium 120 may have one or more channels that are inactive. For example, the portions of the first mirror 130-1 and the second mirror 130-2 aligned with the pillars of the medium 120 forming the channel 7 may not sandwich a portion of the spacer 140. This could result in the channel 7 being inactive (but still serving as structural support). Alternatively, a portion of the spacer 140 may be sandwiched between the first mirror 130-1 and the second mirror 130-2 to make the channel 7 an active channel.

[0025] In some embodiments, specific materials may be used to form the dielectric 120. For example, the dielectric 120 may be formed of a material that transmits through a wavelength range for which the multispectral filter 100 will capture spectral data. In this case, the material may include tantalum-based dielectric materials, niobium-based dielectric materials, silicon dioxide-based dielectric materials, oxide-based dielectric materials, III-V semiconductor-based dielectric materials, gallium phosphide-based dielectric materials, germanium-based dielectric materials, germanium-silicon-based dielectric materials, dielectric-based dielectric materials, polymer-based dielectric materials, nitride-based dielectric materials, phosphide-based dielectric materials, carbide-based dielectric materials, combinations thereof, and / or such materials.

[0026] As further shown in Figure 1, the first mirror 130-1 and the second mirror 130-2 can sandwich the spacer 140 between them. In other words, the spacer 140 can separate the first mirror 130-1 and the second mirror 130-2 by a set of distances, and / or the surface of the spacer 140 can be surrounded by the first mirror 130-1 and the second mirror 130-2. In this case, this set of distances can form different channels. For example, the first portion of the first mirror 130-1 aligned with channel 0 and the second mirror 130-2 can be separated by a first distance, and a first channel can be formed for light of a first wavelength band to pass through. Similarly, the second portion of the first mirror 130-1 aligned with channel 1 and the second mirror 130-2 can be separated by a second distance, due to the stepped structure of the medium 120 and resulting in a stepped structure for the spacer 140, as described in more detail herein, and a second channel can be formed for light of a second wavelength band to pass through. In this configuration, the first channel can be aligned with the first sensor element and can form a first component filter for obtaining spectral data about a first spectral range, and the second channel can be aligned with the second sensor element and can form a second component filter for obtaining spectral data about a second spectral range.

[0027] In some embodiments, mirror 130 may be associated with a specific material. For example, mirror 130 may include a set of metallic mirror layers (e.g., silver), a set of dielectric mirror layers (e.g., alternating layers of silicon hydride and silicon dioxide), etc., to guide a portion of light directed from a light source to a sensor element associated with the multispectral filter 100. In some embodiments, mirror 130 may be aligned with each sensor element of the sensor element array associated with each channel of the multispectral filter 100.

[0028] In some embodiments, the spacer 140 may be an integrally formed spacer, as described in more detail herein. For example, the spacer 140 may be formed by depositing material onto a stepped surface of the first mirror 130-1, such that a first surface of the spacer 140 at its interface with the first mirror 130-1 is a stepped surface, and a second surface of the spacer 140 at its interface with the second mirror 130-2 is a flat surface. In some embodiments, the spacer 140 may be formed of a specific material to give the multispectral filter 100 a specific wavelength range, transmittance (e.g., greater than 50%, greater than 70%, greater than 90%, greater than 95%, greater than 99%, greater than 99.9%, greater than 99.99%, etc.), and / or the like. For example, the spacer 140 may be a silicon-based spacer, an oxide-based spacer, a germanium-based spacer, a silicon-germanium-based spacer, a polymer spacer, a combination thereof, and / or the like. In some embodiments, the spacer 140 may have a refractive index greater than 1.5, greater than 1.7, greater than 2.5, greater than 3.0, greater than 3.5 and / or such.

[0029] In some embodiments, spacer 140 may include a non-solid spacer material. For example, spacer 140 may be formed of a gaseous material (e.g., air or another gaseous material) or a liquid material such that the dimensions of spacer 140 (i.e., the gap between the first mirror 130-1 and the second mirror 130-2) are capable of expanding or contracting, as described in more detail herein. In some embodiments, spacer 140 may include a variety of spacer materials. For example, spacer 140 may include a solid spacer forming a first portion of spacer 140 and covering the first mirror 130-1, and a liquid spacer forming a second portion of spacer 140 and enabling the second mirror 130-2 to translate relative to the first mirror 130-1. Similarly, spacer 140 may include a first solid spacer covering the first mirror 130-1, a second solid spacer covering the second mirror 130-2, and a third liquid spacer disposed between the first and second solid spacers to enable the second mirror 130-2 to translate relative to the first mirror 130-1. In this way, based on its stepped structure, the spacer 140 enables different portions of the multispectral filter 100 to allow light of different wavelength bands to pass through, thus forming different channels. Furthermore, based on the fact that it is formed without multiple layers of material or with fewer than a threshold number of material layers, the spacer 140 can be associated with defects below the threshold level (e.g., surface oxidation within the spacer 140 in amounts below the threshold), thereby improving the optical performance of the multispectral filter 100.

[0030] In some embodiments, forming layers such as medium 120, first mirror 130-1, second mirror 130-2, spacer 140 and / or such layers may include a set of high refractive index material layers (H layers), such as silicon layers, silicon hydride layers, silicon germanium (SiGe) layers, germanium hydride layers, silicon germanium hydride layers and / or such layers. In some embodiments, the formation of layers such as dielectric 120, first mirror 130-1, second mirror 130-2, spacer 140, and / or such layers may include a group of low refractive index materials (L layers), such as silicon dioxide layers, silicon nitride layers, tantalum pentoxide (Ta2O5) layers, niobium pentoxide (Nb2O5) layers, titanium dioxide (TiO2) layers, aluminum oxide (Al2O3) layers, zirconium oxide (ZrO2) layers, yttrium oxide (Y2O3) layers, silicon nitride (Si3N4) layers, combinations thereof, and / or such layers. While some layers may be described as specific materials, such as silicon-germanium, some layers may include (a small amount) phosphors, boron, nitrides, and / or such materials.

[0031] In some embodiments, the formation of layers such as dielectric 120, first mirror 130-1, second mirror 130-2, spacer 140, and / or such layers may be associated with a specific number of layers (e.g., alternating high-refractive-index and low-refractive-index layers in the range of 2 to 200 layers). In some embodiments, one or more layers may be fabricated using sputtering, photolithography, etching, stripping, scraping, annealing, molding, casting, machining, stamping, and / or such processes.

[0032] In some embodiments, each of the layers forming, such as medium 120, first mirror 130-1, second mirror 130-2, spacer 140, and / or such layers, may be associated with a specific thickness. For example, each layer may be associated with a thickness between about 1 nm and about 1500 nm, between about 10 nm and about 500 nm, and / or such thicknesses. Additionally or alternatively, the multispectral filter 100 may be associated with a thickness between about 0.1 µm and about 100 µm, between about 0.25 µm and about 100 µm, and / or such thicknesses.

[0033] In this way, the multispectral filter 100 forms multiple channels for capturing spectral data with respect to multiple wavelength ranges while reducing the amount of defects formed in the spacer 140, thereby improving the optical performance of the multispectral filter 100.

[0034] As indicated above, Figure 1 is provided by way of example only. Other examples are possible and may differ from what is described with respect to Figure 1.

[0035] FIG2 is a diagram of an example embodiment of the multispectral filter 200 described herein. As shown in FIG2, the multispectral filter 200 may include a first substrate 110-1, a second substrate 110-2, a dielectric 120, a first mirror 130-1, a second mirror 130-2, and a spacer 140.

[0036] In some embodiments, the second substrate 110-2 may be deposited on the second mirror 130-2. For example, the second mirror 130-2 may be deposited on the spacer 140, and the second substrate 110-2 may be deposited on the second mirror 130-2. Alternatively or additionally, the second mirror 130-2 may be deposited on the second substrate 110-2. For example, the dielectric 120 may be deposited on the first substrate 110-1, the first mirror 130-1 may be deposited on the dielectric 120, the spacer 140 may be deposited on the first mirror 130-1, the second mirror 130-2 may be deposited on the second substrate 110-2, and the second mirror 130-2 and the second substrate 110-2 may be aligned with the first mirror 130-1 and the first substrate 110-1.

[0037] As indicated above, Figure 2 is provided by way of example only. Other examples are possible and may differ from what is described with respect to Figure 2.

[0038] Figures 3A-3D are diagrams of an exemplary embodiment of the multispectral filter 300 described herein. As shown in Figure 3A, the multispectral filter 300 may include a first substrate 110-1, a second substrate 110-2, a dielectric 120, a first mirror 130-1, a second mirror 130-2, and a spacer 140. As further shown in Figure 3A, the multispectral filter 300 is attached to one or more translation devices 310.

[0039] As further shown in FIG3A, the second mirror 130-2 of the multispectral filter 300 can be movable relative to the first mirror 130-1 to allow the spacer 140 to have a variable thickness, which can change the spectral range of light passing through the channel of the multispectral filter 200. Although some embodiments described herein are described in terms of translating, tilting, or otherwise moving the second mirror 130-2 relative to the fixed first mirror 130-1, the first mirror 130-1 can be moved relative to the second mirror 130-2, and both the first mirror 130-1 and the second mirror 130-2 can be moved by the translation device 310, and / or the like.

[0040] As shown in FIG3B, the second mirror 130-2 is translated relative to the first mirror 130-1 by a translation device 310. For example, the second substrate 110-2 and the second mirror 130-2 may be moved further away from the first substrate 110-1 and the first mirror 130-1 relative to the positions shown in FIG3A. In some embodiments, the translation device 310 may be a focusing element, a voice coil motor, a piezoelectric transducer, a silicon microelectromechanical system (MEMS) device, a thermomechanical device, a bistable beam switch, and / or the like.

[0041] As shown in FIG3C, the second mirror 130-2 can be translated by the translation device 310, such that the second mirror 130-2 is tilted relative to the first mirror 130-1. For example, the second substrate 110-2 can be attached to the tilting device, multiple translation devices, and / or the like. In this way, the wavelength range of the channel of the multispectral filter 300 can be further configured by reducing the spacing between the second mirror 130-2 and the first mirror 130-1 for a first portion of the channel, increasing the spacing between the second mirror 130-2 and the first mirror 130-1 for a second portion of the channel, maintaining the spacing between the second mirror 130-2 and the first mirror 130-1 for a third portion, and / or the like.

[0042] In some embodiments, the moving device can move the second mirror 130-2 relative to the first mirror 130-1 based on a specific timing configuration. For example, during the readout of a sensor element aligned with a channel of the multispectral filter 300, the moving device can be triggered to move the second mirror 130-2 so that some channels are associated with different wavelength ranges while others remain in their default wavelength range. As an example, when the multispectral filter includes multiple channels having a common wavelength range, as shown in Figures 1 and 2 with respect to multiple channels 7, the moving device can be triggered to read out a first sensor element of the first channel associated with the common wavelength range at a first position on the second mirror 130-2, and a second sensor element of the second channel associated with the common wavelength range at a second position on the second mirror 130-2. In this way, the multispectral filter 200 can use a common channel to achieve multiple spectral ranges. Furthermore, the moving device can read out the first sensor element at both the first and second positions, resulting in the use of a single channel to capture multiple spectral ranges.

[0043] In some embodiments, the spacer 140 may be configured to achieve a variable spacer width based on the translation of the second mirror 130-2 relative to the first mirror 130-1. For example, the spacer 140 may be a gas spacer or a liquid spacer that can be encapsulated by the multispectral filter 300 to allow the gas spacer or liquid spacer to expand and / or contract when the second mirror 130-2 is translated relative to the first mirror 130-1. Additionally or alternatively, the spacer 140 may be configured such that additional gas spacer material or liquid spacer material may be provided into and / or removed from the gap between the second mirror 130-2 and the first mirror 130-1 to allow the spacer to provide a variable thickness.

[0044] As shown in FIG3D, a plurality of spacers 140 (e.g., first spacer 140-1 and second spacer 140-2) may be arranged between the first mirror 130-1 and the second mirror 130-2. For example, the first spacer 140-1 may be a solid spacer covering the first mirror 130-1, and the second spacer 140-2 may be a gas (or liquid) spacer that realizes a variable spacing between the first mirror 130-1 and the second mirror 130-2.

[0045] As indicated above, Figures 3A to 3D are provided only as examples. Other examples are possible and may differ from what is described with respect to Figures 3A to 3D.

[0046] FIG4 is a flowchart of an example procedure 400 for manufacturing the multispectral filter described herein. In some embodiments, one or more procedure blocks of FIG4 may be performed by a deposition apparatus (e.g., an etching apparatus, a sputtering apparatus, a photolithography apparatus, and / or the like) during the manufacturing process.

[0047] As shown in FIG4, process 400 may include arranging a dielectric on a substrate to form a stepped structure (block 410). For example, a deposition apparatus may deposit a dielectric on the substrate to form a stepped structure. In some embodiments, the deposition apparatus may deposit multiple layers of dielectric to form a stepped structure. For example, multiple layers of photolithography material may be deposited, and multiple layers of dielectric may be deposited to form a stepped structure. In this case, the multiple layers of photolithography material may be combined with a light mask to expose to light, selectively removing the photolithography material and allowing the multiple layers of dielectric to form a stepped structure. Photolithography formation of a stepped structure for a dielectric is described in detail with reference to FIGS. 5A to 5K. Additionally or alternatively, the dielectric may be arranged on the substrate to form a stepped structure using an etching process. For example, the dielectric may be deposited on the substrate and then etched to form a stepped structure. Although some embodiments described herein are described in terms of photolithography or etching processes, other processes for forming stepped dielectric structures are possible.

[0048] As shown in FIG4, program 400 may include a first mirror of a multi-channel filter arranged on a medium to form a stepped mirror structure (block 420). For example, a deposition apparatus may deposit the first mirror on the medium. In this case, the first mirror may be formed into a stepped structure based on a medium having a stepped structure, and the first mirror is deposited on the medium.

[0049] As shown in FIG. 4, the procedure 400 may include spacers (block 430) for arranging a multichannel filter on a first mirror. For example, a deposition apparatus may deposit spacers on the first mirror. In this case, the spacers may be solid spacers deposited using a single deposition step, which reduces the impact on optical performance based on surface layer oxidation compared to depositing spacers using multiple deposition and etching steps. Alternatively or additionally, the spacers may be liquid or gas spacers that can be inserted into a cavity formed by the first and second mirrors, which can realize a variable-spacer binary multispectral filter with a translational mirror. In some embodiments, the spacers may form a flat surface. For example, the spacers may be deposited on the first mirror such that a first surface connected to the stepped mirror surface of the first mirror via an interface is stepped, and a second surface on the opposite side of the spacers is flat. In this case, the spacers may be etched to remove a portion of the spacers to form a flat surface. In some embodiments, the first mirror or medium may form an etch stop layer for etching the spacers to form a flat surface.

[0050] As shown in FIG. 4, process 400 may include arranging a second mirror on a second surface of the spacer to form a plane mirror (block 440) for a multi-channel filter. For example, a deposition apparatus may deposit the second mirror on the second surface of the spacer such that the mirror is a plane mirror. In some embodiments, the second mirror may be aligned with a first mirror. For example, the second mirror may be deposited on another substrate, and the second mirror and the other substrate may be aligned with the first mirror such that the second mirror and the other substrate are translatable relative to the first mirror to form a spacer of variable thickness. In this way, a multispectral filter may be formed with multiple channels.

[0051] Although Figure 4 shows example blocks of program 400, in some embodiments program 400 may include additional blocks, fewer blocks, different blocks, or blocks arranged differently compared to those depicted in Figure 4. Additionally or alternatively, two or more blocks of program 400 may be executed in parallel.

[0052] Figures 5A to 5E are diagrams of example embodiments related to procedure 400. Figures 5A to 5K illustrate example procedures for manufacturing the multispectral filter described herein.

[0053] As shown in FIG5A and by schematic diagram 500, photoresist 552 may be deposited on substrate 110. As shown by schematic diagram 502, photomasks 554 and 556 may be located on photoresist 552.

[0054] As shown in FIG. 5B and by schematic diagram 504, the portion of photomasks 554 and 556 and the portion of photoresist 552 not covered by photomasks 554 and 556 can be exposed to light. As shown by schematic diagram 506, based on the exposure to light, the portion of photoresist 552 not covered by photomasks 554 and 556 can remain disposed on substrate 110.

[0055] As shown in FIG. 5C and by schematic diagram 508, a dielectric layer 120 may be deposited onto the substrate 110 and the remaining portion of the photoresist 552. As shown by schematic diagram 510, the remaining portion of the photoresist 552 may be removed. In this case, the portion of the dielectric layer 120 deposited onto the substrate 110 may be retained, forming a first step, wherein the remaining portion of the photoresist 552 is removed. As shown by schematic diagram 512, another photoresist layer 552 may be deposited onto the dielectric 120 and the substrate 110.

[0056] As shown in Figure 5D and by schematic diagram 514, based on the use of another light mask (not shown) and based on the exposure to light, only a portion of the other photoresist 552 can be retained. As shown by schematic diagram 516, another dielectric 120 can be deposited.

[0057] As shown in FIG5E and by schematic diagram 518, another layer of photoresist 552 can be removed, resulting in two steps forming in the dielectric 120. As shown by schematic diagram 520, another layer of photoresist 552 can be deposited on the dielectric 120 and the substrate 110.

[0058] As shown in FIG5F and by schematic diagram 522, based on the use of another light shield (not shown) and based on the exposure to light, only a portion of the other photoresist layer 552 can be retained. As shown by schematic diagram 524, another dielectric layer 120 can be deposited.

[0059] As shown in FIG5G and by schematic diagram 526, another layer of photoresist 552 can be removed, resulting in the formation of three steps in the dielectric 120. As shown in schematic diagram 528, another layer of photoresist 552 can be deposited on the dielectric 120 and the substrate 110.

[0060] As shown in FIG5H and by schematic diagram 530, based on the use of another light shield 554 and 556 (not shown) and based on the exposure to light, only a portion of the other photoresist 552 can be retained. As shown by schematic diagram 532, another dielectric 120 can be deposited.

[0061] As shown in FIG. 5I and by schematic diagram 534, another layer of photoresist 552 can be removed, resulting in the formation of four steps in the dielectric 120. As shown in schematic diagram 536, after a further photolithography step, a set of six steps can be formed by the dielectric 120, wherein the channel at each edge of the multispectral filter is a common channel.

[0062] As shown in FIG. 5J and by schematic diagram 538, the first mirror 558 can be deposited onto a set of six steps formed by the medium 120. As shown by schematic diagram 540, the spacer 560 can be deposited onto the first mirror 558. In this case, based on the first mirror 558 having a stepped surface, the first surface of the spacer 560 at the interface with the first mirror 558 is stepped. Furthermore, the second surface of the spacer 560 is a non-planar surface.

[0063] As shown in FIG. 5K and by schematic diagram 542, the etching process can remove a portion of the second surface of the spacer 560 to make the second surface of the spacer 560 a flat surface. As shown by schematic diagram 544, the second mirror 562 is deposited on the flat second surface of the spacer 560. In this case, based on the first surface being stepped and the second surface being flat, the spacer 560 forms multiple channels of a multispectral filter without requiring multilayer deposition of the spacer 560.

[0064] As indicated above, Figures 5A to 5K are provided only as examples. Other examples are possible and may differ from what is described with respect to Figures 5A to 5K.

[0065] FIG6 is a diagram of an exemplary embodiment 600 described herein. As shown in FIG6, the exemplary embodiment 600 includes a sensor system 610. The sensor system 610 may be part of an optical system and may provide an electrical output corresponding to sensor determination. For example, the sensor system 610 may be part of a biometric system, a security system, a health monitoring system, an object recognition system, a spectral recognition system, an imaging system, and / or the like. The sensor system 610 includes an optical filter structure 620, which includes an optical filter 630 and a set of light sensors 640 (e.g., an array of sensor elements). For example, the optical filter structure 620 may include an optical filter 630 that performs a bandpass blocking function and / or the like. In some embodiments, the optical filter 630 may be a multispectral filter, such as a multispectral filter having a stepped medium and a monolithic spacer, a multispectral filter having a variable thickness spacer, and / or the like. The sensor system 610 includes a light emitter 650 that emits a light signal toward a target 660 (e.g., a person, object, etc.).

[0066] Although the embodiments described herein can be described from the perspective of optical filters in a sensor system, the embodiments described herein can be used in another type of system, or can be used outside the sensor system, etc.

[0067] In some embodiments, an alternative arrangement of the optical filter 630 and the photosensor 640 may be utilized. For example, instead of allowing the second portion of the optical signal to pass collinearly with the input optical signal, the optical filter 630 may guide the second portion of the optical signal in a different direction toward the photosensor 640, which is positioned differently. In some embodiments, the photosensor 640 may be an avalanche photodiode, an indium gallium arsenide (InGaAs) detector, an infrared detector, etc.

[0068] As shown in FIG. 6 and further indicated by component symbol 670, the input optical signal is directed to the optical filter structure 620. The input optical signal may include visible light, near-infrared light, mid-infrared light, and / or such light emitted by the light emitter 650, as well as ambient light from the environment in which the sensor system 610 is being utilized. For example, when the optical filter 630 is a bandpass multispectral filter with multiple channels, the light emitter 650 may direct near-infrared light of multiple wavelength ranges toward the object to which the spectral measurement is performed, and the near-infrared light may be reflected from the target 660 (e.g., the object) toward the light sensor 640 to allow the light sensor 640 to perform measurements of near-infrared light of multiple wavelength ranges. In this case, ambient light may be directed to the light sensor 640 from one or more ambient light sources (e.g., a light bulb or the sun).

[0069] In another example, multiple beams can be directed to target 660, and a subset of the multiple beams can be reflected onto optical filter structure 620, as shown, optical filter structure 620 can be arranged at an angle relative to photosensor 640. In some embodiments, another angle may be used. In some embodiments, optical filter structure 620 may be disposed directly and / or formed directly onto photosensor 640, disposed at a distance from photosensor 640 (e.g., by free-space optics), etc. For example, optical filter structure 620 may be coated and patterned onto photosensor 640 using, for example, photolithography, sputtering deposition techniques (e.g., using argon and helium as an inert gas mixture for sputtering deposition), etc.

[0070] In another example, the light emitter 650 can direct near-infrared light toward another type of target 660, such as for detecting gestures in a gesture recognition system, detecting objects near a vehicle, detecting objects near a blind person, detecting the proximity of objects (e.g., using LIDAR technology), etc., and thus, near-infrared light and ambient light can be directed toward the light sensor 640.

[0071] In some embodiments, a portion of the optical signal passes through the optical filter 630 and the optical filter structure 620. For example, different spacer thicknesses in different channels of the optical filter 630 can cause a first portion of the light to be reflected and a second portion of the light to pass through. In this case, the optical filter 630 may include multiple channels formed by a combination of spacers and a stepped medium, and each channel can allow light of a different wavelength to pass through. Alternatively, two or more channels can allow light of a common wavelength to pass through.

[0072] As shown in FIG6, based on the portion of the light signal transmitted to the light sensor 640, the light sensor 640 can provide the sensor system 610 with an output electrical signal, which is further shown by component symbol 680, for example, to perform spectral measurements, recognize user gestures, detect the presence of objects, etc.

[0073] As described above, Figure 6 is provided only as an example. Other examples are possible and may differ from what is described with respect to Figure 6.

[0074] The foregoing disclosure provides illustrations and descriptions, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations are possible based on the foregoing disclosure, or may be obtained from practice of the embodiments.

[0075] This document describes some implementation methods in conjunction with thresholds. As used herein, satisfying a threshold can refer to a value greater than a threshold, more than a threshold, higher than a threshold, greater than or equal to a threshold, less than a threshold, less than a threshold, lower than a threshold, less than or equal to a threshold, equal to a threshold, etc.

[0076] Although specific combinations of features are stated in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of possible embodiments. In fact, many of these features can be combined in ways not specifically stated in the claims and / or not disclosed in the specification. Although each listed dependent claim may be directly subordinate to only one claim, the disclosure of possible embodiments includes each dependent claim in combination with every other claim in the set of claims.

[0077] No element, action, or instruction used herein should be construed as essential or necessary unless explicitly stated otherwise. Furthermore, as used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more.” Additionally, as used herein, the term “set” is intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, etc.) and may be used interchangeably with “one or more.” The term “one” or similar language is used where only one item is intended to be described. Furthermore, as used herein, the terms “has,” “have,” “having,” and / or similar words are intended to be open-ended terms. Additionally, the phrase “based on” is intended to mean “at least partially based on” unless explicitly stated otherwise. [Simplified Explanation of the Diagram]

[0008] [Figure 1] is a diagram of an example implementation of the multispectral filter described herein.

[0009] [Figure 2] is a diagram of an example implementation of the response equalization of the filter channel of the multispectral filter described herein.

[0010] [Figures 3A to 3D] are figures of an example implementation of the multispectral filter described herein.

[0011] [Figure 4] is a diagram of an example program for manufacturing the multispectral filter described herein.

[0012] [Figures 5A to 5K] are figures of an example implementation of a multispectral filter related to the example procedure of Figure 4.

[0013] [Figure 6] is a diagram of an example embodiment of a sensor system including the multispectral filter described herein.

Claims

1. A filter, comprising: substrate; The first mirror includes a stepped surface of the first mirror; An integral spacer is arranged on the stepped surface of the first mirror; And a second mirror, which includes a flat surface of the integral spacer; wherein the first mirror and the second mirror clamp at least a portion of the integral spacer, wherein the stepped surface of the first mirror is located between the substrate and the second mirror, and wherein a portion of the stepped surface of the first mirror is disposed on a portion of the substrate.

2. The filter according to claim 1, further comprising: A stepped medium, wherein the first mirror is disposed on the stepped medium.

3. The filter according to claim 2, wherein, The stepped medium is stepped along a single axis.

4. The filter according to claim 2, wherein, The stepped medium is stepped along multiple axes.

5. The filter according to claim 1, wherein, The monolithic spacers include silicon-based spacers.

6. The filter according to claim 1, further comprising: The substrate includes an array of sensor elements; And a stepped medium between the substrate and the stepped surface of the first mirror.

7. The filter according to claim 1, wherein, A first portion of the first mirror and a first portion of the second mirror are separated by a first distance and configured to form a first channel, the first channel allowing light of a first wavelength band to pass through and be aligned with a first sensor element; and wherein a second portion of the first mirror and a second portion of the second mirror are separated by a second distance and configured to form a second channel, the second channel allowing light of a second wavelength band to pass through and be aligned with a second sensor element.

8. The filter according to claim 1, wherein the second mirror is movable relative to the first mirror.

9. A filter, comprising: substrate; A mirror, comprising the stepped surface of the mirror; and spacers, wherein: the stepped surface of the mirror is located between the substrate and a different mirror, and a portion of the stepped surface of the mirror is disposed on the substrate.

10. The filter according to claim 9, further comprising: A stepped medium between the substrate and the stepped surface of the mirror.

11. The filter according to claim 9, wherein the spacer comprises: Gas spacers or liquid spacers.

12. The filter according to claim 9, wherein the spacer comprises a silicon hydride-based spacer.

13. The filter according to claim 9, wherein, The first portions of the different mirrors are arranged on different portions of the stepped surface of the mirrors, and the second portions of the different mirrors are arranged on the flat surface of the spacer.

14. A method for manufacturing a stepped optical filter, comprising: A first mirror is deposited, which has a stepped mirror structure and is used as a filter. On the first mirror, spacers for the filter are arranged using a single deposition step; A second mirror is deposited on at least one flat surface of the spacer, the second mirror having a flat mirror structure, wherein a portion of the stepped surface of the first mirror is disposed on a portion of the substrate.

15. The method according to claim 14, wherein the spacer comprises a silicon-based spacer.

16. The method according to claim 15, wherein depositing the second mirror comprises: The second mirror is deposited on the flat surface of the spacer and on a portion of the first mirror.

17. The method according to claim 14, further comprising: On the substrate of the filter, a stepped structure of the medium is formed using one or more photolithography materials or etching processes.

18. The method according to claim 17, wherein depositing the first mirror comprises: The first mirror is deposited on the stepped structure of the medium.

19. The method according to claim 17, further comprising: A different substrate is deposited on the second mirror.

20. A filter, comprising: A stepped medium includes: a first channel and a second channel, the second channel being inactive; a mirror disposed on the stepped medium; and an integral spacer disposed on at least a portion of the stepped surface of the mirror, wherein a portion of the stepped surface of the mirror is disposed on a portion of a substrate.

21. The filter according to claim 20, wherein, The stepped medium is stepped along a single axis.

22. The filter according to claim 20, wherein, The stepped medium is stepped along multiple axes.

23. The filter according to claim 20, wherein, The monolithic spacers include: silicon-based spacers, oxide-based spacers, germanium-based spacers, silicon-germanium-based spacers, or polymer spacers.

24. The filter according to claim 20, wherein, The integral spacer includes: a first surface that is stepped and at the interface with the stepped surface of the mirror, and a second surface that is flat.

25. The filter according to claim 20, wherein, The monolithic spacer has a refractive index greater than 1.

5.

26. A filter, comprising: A stepped medium comprising: a first channel forming a specific channel among a plurality of channels of the filter and disposed at a first outer edge of the filter; a second channel forming the specific channel and disposed at a second outer edge of the filter; and an integral spacer disposed at least partially between the first channel and the second channel, wherein a portion of the stepped surface of a mirror is disposed on a portion of a substrate.

27. The filter according to claim 26, wherein, The stepped medium further includes: two or more other channels among the plurality of channels, the two or more other channels being located between the first channel and the second channel.

28. The filter according to claim 27, wherein, The integral spacer is arranged on a stepped surface above the two or more other channels.

29. The filter according to claim 27, further comprising: The mirror is arranged on the stepped medium.

30. The filter according to claim 27, further comprising: Mirrors arranged on the integral spacer.

31. The filter according to claim 27, wherein, The stepped dielectric is formed of one or more of the following materials: tantalum-based dielectric material, niobium-based dielectric material, silicon dioxide-based dielectric material, oxide-based dielectric material, III-V semiconductor-based dielectric material, gallium phosphide-based dielectric material, germanium-based dielectric material, germanium-silicon-based dielectric material, dielectric-based dielectric material, polymer-based dielectric material, nitride-based dielectric material, phosphide-based dielectric material, or carbide-based dielectric material.

32. The filter according to claim 27, wherein, The integral spacer is at least one of the following: a gas spacer or a liquid spacer.

33. A filter, comprising: A stepped medium comprising: a first channel and a second channel; a mirror disposed on the stepped medium, wherein the mirror comprises one or more of the following: a metallic mirror layer or a dielectric mirror layer; and an integral spacer disposed above one or more of the first channel or the second channel, wherein the integral spacer is at least one of the following: a gas spacer or a liquid spacer, wherein a portion of the stepped surface of the mirror is disposed on a portion of a substrate.

34. The filter according to claim 33, wherein the integral spacer is disposed on the stepped surface of the mirror.

35. The filter according to claim 33, wherein the stepped medium further comprises: Two or more other pillars that form two or more other channels.

36. The filter according to claim 33, wherein: The stepped dielectric is deposited on the substrate.

37. A filter, comprising: A stepped medium comprising: a first channel and a second channel; an integral spacer disposed above one or more of the first channel or the second channel, wherein the integral spacer is at least one of the following: a gas spacer or a liquid spacer; a mirror disposed on the stepped medium; and a substrate deposited above the mirror, wherein a portion of the stepped surface of the mirror is disposed on a portion of the substrate.

38. The filter according to claim 37, wherein the mirror comprises a metallic mirror layer.

39. The filter according to claim 37, wherein the stepped medium further comprises: One or more other channels.

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