An olfactory odor array sensor and a method of manufacturing the same

Abstract

This invention relates to an olfactory odor array sensor and its fabrication method. The olfactory odor array sensor includes: a substrate having an array of through holes; a sensing membrane disposed on the inner wall of the through holes, whose resistance changes upon reaction with a analyte; electrodes for applying a voltage to the sensing membrane; and a modulation layer for regulating carrier transport between the electrodes and the sensing membrane. The electrodes include a plurality of first electrodes disposed on the top of the substrate along its thickness direction and a plurality of second electrodes disposed on the bottom of the substrate. The overlapping area of ​​the projections of the first and second electrodes along the thickness direction of the substrate covers the plurality of sensing membranes to form pixels for sensing. When the olfactory odor array sensor detects a gas, the grid formed by the first and second electrodes can transmit current reflecting the resistance change of the sensing membrane of each pixel after reacting with the gas.

Description

Technical Field

[0001] This invention relates to the field of olfactory sensor technology, and in particular to an olfactory odor array sensor and its preparation method. Background Technology

[0002] Olfactory sensing devices are widely used in applications ranging from environmental monitoring to disease diagnosis. However, compared to physical parameter-based sensing devices such as light-based visual sensing devices, sound-based auditory sensing devices, and pressure-based tactile sensing devices, the development of chemical parameter-based sensing devices, including olfactory and gustatory sensing devices, is limited due to the high complexity of processing chemical information. Humans' five senses—sight, hearing, smell, taste, and touch—are the five main channels through which the brain acquires information from the surrounding environment. While sight is the primary sense for humans, smell and hearing may be the primary senses for many other animals (such as dogs and cats). In the information technology era, artificial sensing devices, such as cameras and microphones, have become key components of many intelligent systems. The development of artificial olfactory devices is crucial for ensuring human well-being and establishing artificial senses in intelligent systems (such as advanced robots and portable intelligent devices). Therefore, research on odor sensors is essential.

[0003] For example, Chinese Patent Publication No. CN112400108A discloses an odor sensor, which includes: an ion sensor, a substance adsorption membrane, a reference electrode, and a passivation layer. The ion sensor is formed on a substrate by forming at least one sensing portion of a sensing membrane that changes its potential according to the state of the measured object. The substance adsorption membrane is disposed on the sensing membrane and changes its state by adsorbing odor substances. The reference electrode applies a reference voltage to the substance adsorption membrane and is disposed such that it is separate from the sensing membrane and does not overlap with the sensing portion when viewed from the thickness direction of the substrate. The passivation layer is provided to cover the ion sensor, and the substance adsorption membrane is provided to cover the passivation layer. The sensing membrane contacts the substance adsorption membrane through a first opening in the passivation layer, and the reference electrode is disposed between the substance adsorption membrane and the substrate, contacting the substance adsorption membrane through a second opening in the passivation layer.

[0004] Chinese patent CN113203770A discloses an odor sensor, including a sensor element. The sensor element includes an electrode layer, a flexible substrate, and a sensing layer arranged sequentially. The flexible substrate and the sensing layer are different flexible polymers that can generate a potential difference under external force. The sensing layer has multiple pore sites, and the flexible substrate is exposed from the pore sites. Chemical modifiers are disposed on the pore sites to form odor sensing units. At least some of the pore sites have different chemical modifiers. The chemical modifiers are used to react with gases to cause potential changes. Different odor gases react with different chemical modifiers.

[0005] Chinese Patent Publication No. CN110108757A discloses a gas sensor, a sensor fabrication method, and a sensor array that can reduce lead wire damage. The gas sensor includes: a first substrate, a gas detection component disposed on the first substrate, a plurality of first pins of the gas sensor, and a package cap, wherein: the gas detection component is directly or indirectly electrically connected to the first pins, and the gas detection component and the first pins are disposed on the same side of the first substrate; the package cap is bonded to the first substrate to protect the gas detection component, and the first pins are exposed outside the package cap.

[0006] Existing sensors lag behind the effectiveness of biological olfaction in terms of gas distinguishability and detection accuracy. The main reason is that the number of sensing units that function as biological olfactory receptors in the sensors is limited, far less than the number of olfactory receptors in the biological olfactory system, resulting in limited diversity in the reactions of the sensors to gases.

[0007] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides an olfactory odor array sensor. The olfactory odor array sensor includes: a substrate having an array of through holes; a sensing membrane disposed on the inner wall of the through holes, whose resistance changes upon reaction with a analyte; electrodes applying a voltage to the sensing membrane; and a modulation layer regulating carrier transport between the electrodes and the sensing membrane. Preferably, the electrodes, the sensing membrane, and the modulation layer are arranged in an overlapping manner along the thickness direction of the substrate. Preferably, the modulation layer may be disposed on both sides of the substrate.

[0009] Preferably, the modulation layer comprises at least one type of metal particles distributed in a gradient. Preferably, the modulation layer is in contact with the sensing membrane, such that the sensing membranes arranged in an array via the through-holes are different. Preferably, the modulation layer is composed of metal oxides of different types or compositions. Because different sensing materials have different lattice and band structures, the resistance encountered by charge carriers (electrons) on each sensing membrane when flowing through the modulation layer to the electrode is different, thereby constructing sensing membranes with different sensitivity characteristics.

[0010] According to a preferred embodiment, the electrode includes a plurality of first electrodes disposed on the top of the substrate along the thickness direction of the substrate and a plurality of second electrodes disposed on the bottom of the substrate. Preferably, the overlapping area of ​​the projections of the plurality of first electrodes and the plurality of second electrodes in the thickness direction of the substrate covers the plurality of sensing films to form pixels for sensing.

[0011] Preferably, the plurality of first electrodes and the plurality of second electrodes form a grid by arranging the plurality of pixels in the projection overlap area, thereby arranging the plurality of pixel arrays.

[0012] According to a preferred embodiment, the modulation layer is disposed between the electrode and the sensing film. Preferably, at least one metal particle is distributed in a gradient in the modulation layer. Preferably, the area where the modulation layer is disposed may include one of the top end face of the substrate, the bottom end face of the substrate, the contact area between the top of the substrate and the first electrode, and the contact area between the bottom of the substrate and the first electrode, thereby providing a modulation layer that alters the electron (carrier) flow capability in a sensing circuit composed of a first electrode, a sensing film, and a second electrode connected in series.

[0013] Preferably, the modulation layer causes differences in the transport of charge carriers after the reaction between the pixel and the sensing film and the object being measured, thereby increasing the diversity of pixels in the olfactory odor array sensor 100.

[0014] According to a preferred embodiment, the first electrode and the modulation layer are provided with openings that match the through-hole to form an airflow channel, allowing the object to be measured to contact the sensing membrane. Preferably, the second electrode, the insulating layer, and the heating layer may also be provided with openings that match the through-hole.

[0015] According to a preferred embodiment, the edge of the sensing film contacts the modulation layer and the second electrode respectively, so that the substrate is electrically conductive along the thickness direction.

[0016] According to a preferred embodiment, the olfactory array sensor further includes a heating layer capable of heating the sensing membrane. The heating layer is disposed at the bottom of the second electrode, and an electrically insulating insulating layer is disposed between the heating layer and the second electrode. Preferably, the heating layer and the insulating layer may also be disposed on the top electrode.

[0017] This invention also provides a method for fabricating an olfactory odor array sensor. The fabrication method includes:

[0018] Sensing material is deposited in the vias arranged in a substrate array to form a sensing film covering the vias;

[0019] A modulation layer is deposited on top of the substrate.

[0020] Preferably, the modulation layer comprises at least one type of metal particles distributed in a gradient. Preferably, the modulation layer is in contact with the sensing membrane, such that the sensing membranes arranged in an array via the through-holes are different. Preferably, the modulation layer is composed of metal oxides of different types or compositions. Because different sensing materials have different lattice and band structures, the resistance encountered by charge carriers (electrons) on each sensing membrane when flowing through the modulation layer to the electrode is different, thereby constructing sensing membranes with different sensitivity characteristics.

[0021] According to a preferred embodiment, the preparation method further includes:

[0022] Deposit electrodes for applying voltage to the sensing membrane;

[0023] Depositing an insulating layer for electrical insulation;

[0024] Deposit a heating layer for heating the sensing membrane.

[0025] Preferably, the electrode deposition includes depositing a plurality of first electrodes on the top of the substrate and depositing a plurality of second electrodes on the bottom of the substrate. Preferably, the insulating layer is deposited at the bottom of the second electrodes, and the heating layer is deposited at the bottom of the insulating layer.

[0026] The present invention also provides an odor recognition system. The odor recognition system includes an olfactory odor array sensor, a signal readout circuit, and a processing module. Preferably, the olfactory odor array sensor includes a plurality of pixels arranged in an array and a plurality of electrodes. The electrodes include a plurality of first electrodes disposed above the pixels and a plurality of second electrodes disposed below the pixels. The plurality of first electrodes and the plurality of second electrodes form a grid by arranging the plurality of pixels on a projected overlapping area. Preferably, the processing module is connected to the plurality of electrodes through the signal readout circuit to obtain the resistance change generated by each pixel in response to the measured object, thereby generating a feature image of the measured object. Preferably, each pixel includes a plurality of sensing films, and a modulation layer for regulating carrier transport is disposed between the sensing films and the electrodes.

[0027] Preferably, the grid formed by the plurality of electrodes divides the arrayed sensing films into a plurality of pixels, and the resistance change generated by the reaction of the sensing films with the measured object is processed by the processing module and converted into the color of the pixels.

[0028] The present invention also provides a robot. The robot is equipped with a target recognition system combining visual and olfactory perception. Preferably, the target recognition system includes: at least one olfactory sensor, at least one visual sensor, and a controller. The olfactory sensor and the visual sensor are respectively signal-connected to the controller. The olfactory sensor is capable of determining first attribute information of the target object by olfactory recognition. The visual sensor is capable of determining second attribute information of the target object by visual recognition. The controller is capable of determining the object type of the target object based on the first attribute information determined by the olfactory sensor and / or the second attribute information determined by the visual sensor. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the composition of an olfactory odor array sensor according to a preferred embodiment of the present invention;

[0030] Figure 2 This is a cross-sectional schematic diagram of an olfactory odor array sensor according to a preferred embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the electrode arrangement according to a preferred embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the fabrication process of an olfactory odor array sensor according to a preferred embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram illustrating the working principle of an odor recognition system according to a preferred embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram illustrating a preferred embodiment of the present invention that integrates an odor recognition system with a robot;

[0035] Figure 7 This is a schematic diagram of a test experiment of a robot according to a preferred embodiment of the present invention.

[0036] List of reference numerals

[0037] 100: Odor array sensor; 101: Substrate; 102: Sensing film; 103: Electrode; 104: Modulation layer; 105: Isolation layer; 106: Heating layer. Detailed Implementation

[0038] The following is in conjunction with the appendix Figures 1 to 7 Please provide a detailed explanation.

[0039] Example 1

[0040] This embodiment provides an olfactory odor array sensor 100. See also... Figure 1 and Figure 2 Preferably, the olfactory odor array sensor 100 may include a substrate 101 having an array of through holes; a sensing membrane 102 disposed on the inner wall of the through holes, whose resistance changes by reacting with the analyte; an electrode 103 applying a voltage to the sensing membrane 102; and a modulation layer 104 regulating carrier transport between the electrode 103 and the sensing membrane 102. Preferably, the analyte is a gas.

[0041] Preferably, the substrate 101 can be made of porous alumina, porous zirconia, or other porous ceramic substrates. Porous alumina has a unique structure with a plurality of pores extending along its thickness direction, and these pores are arranged in an array on the porous alumina. Preferably, the substrate 101 is made of porous alumina, so that the substrate 101 has an array of through holes. Preferably, the porous alumina used in this embodiment is freestanding porous alumina, with a thickness ranging from 10 to 100 μm, a spacing between the center of the through hole and the center of the adjacent through hole ranging from 300 to 500 nm, and a pore size ranging from 100 to 350 nm.

[0042] Preferably, a sensing membrane 102 is disposed on the inner wall of the through hole. Preferably, the sensing membrane 102 changes its own resistance value by reacting with the object being measured. Preferably, the sensing membrane 102 uniformly covers the inner wall of the through hole, thereby electrically conducting the upper and lower surfaces of the substrate 101, and since the through holes are arranged in an array on the substrate 101, the sensing membrane 102 can form a sensing array after covering the inner wall of the through hole.

[0043] Preferably, using porous ceramic substrates such as porous alumina as the substrate 101 not only allows the substrate 101 to have a larger surface-to-volume ratio, thereby increasing the area of ​​the sensing membrane 102, but also the through holes on the porous alumina facilitate the entry of gas molecules. When the olfactory odor array sensor 100 detects gas, it is beneficial for the gas molecules to interact effectively with the sensing membrane 102 in the through holes, thereby improving the sensing performance of the olfactory odor array sensor 100.

[0044] Preferably, the electrode 103 includes a plurality of first electrodes disposed on the top of the substrate 101 along the thickness direction of the substrate 101 and a plurality of second electrodes disposed on the bottom of the substrate 101. Preferably, the projections of the plurality of first electrodes and the plurality of second electrodes in the thickness direction of the substrate 101 form an overlapping region. These overlapping regions can cover a plurality of sensing films 102 to form pixels for sensing.

[0045] See Figure 2 Preferably, the first electrode and the modulation layer 104 are provided with openings that match the through holes to form an airflow channel, so that the object to be measured can contact the sensing membrane 102.

[0046] See Figure 3Preferably, a plurality of first electrodes are arranged in parallel above the substrate 101, and a plurality of second electrodes are arranged in parallel below the substrate 101, and the projections of the plurality of first electrodes and the plurality of second electrodes in the thickness direction of the substrate 101 form a grid. Preferably, the plurality of first electrodes are arranged in a row above the substrate 101, and the plurality of second electrodes are arranged in a column below the substrate 101. Preferably, the plurality of sensing films 102 covered by the overlapping area of ​​the plurality of first electrodes and the plurality of second electrodes constitute a pixel for detecting gas.

[0047] Preferably, when the olfactory odor array sensor 100 detects gas, the grid formed by several first electrodes and several second electrodes can transmit current changes reflecting the sensing membrane 102 in each pixel. Preferably, when detecting gas, gas molecules enter the through-hole and adsorb onto the surface of the sensing membrane 102, reacting with adsorbed oxygen on the surface of the sensing membrane 102 to release electrons, causing a change in the electrical signal between the first and second electrodes, thereby detecting the gas by detecting the current changes in each pixel. Preferably, the material used for the sensing membrane 102 can be PdO / SnO2. Preferably, the electrode 104 can be a crossbar electrode.

[0048] Preferably, the modulation layer 104 is disposed between the electrode 103 and the sensing film 102. Preferably, at least one metal particle is distributed in a gradient in the modulation layer 104. Preferably, the gradient distribution of metal particles in the modulation layer 104 causes differences in carrier transport after the pixel reacts with the gas, thereby increasing the diversity of pixels in the olfactory odor array sensor 100. Preferably, the area where the modulation layer 104 is disposed may include one of the following: the top end face of the substrate 101, the bottom end face of the substrate 101, the area where the top of the substrate 101 contacts the first electrode, and the area where the bottom of the substrate 101 contacts the second electrode, thereby disposing a modulation layer 104 that alters the electron (carrier) flow capability in the sensing circuit composed of the first electrode, the sensing film 102, and the second electrode connected in series. Preferably, the modulation layer 104 in the pixel region is composed of different types of metal particles distributed in a gradient. Different types and concentrations of metal particles have different lattice and band structures, resulting in varying resistance to electrons (charge carriers) released from the reaction between the surface of the gas sensing film 102 and adsorbed oxygen as they flow through the modulation layer 104. This causes each pixel to exhibit different response characteristics to the detected gas. Preferably, the present invention uses the modulation layer 104 to perform secondary modulation on the degree of resistance change caused by the gas adsorption reaction in each pixel, thereby differentiating the response characteristics of each pixel to the detected gas.

[0049] Preferably, the area where the modulation layer 104 is disposed can be a combination of multiple regions. For example, the combination region is one of the following four combinations: the top end face and the bottom end face of the substrate 101, the area where the top end face and the bottom of the substrate 101 are in contact with the second electrode, the area where the top of the substrate 101 is in contact with the first electrode and the bottom end face of the substrate 101, and the area where the top of the substrate 101 is in contact with the first electrode and the area where the bottom of the substrate 101 is in contact with the second electrode.

[0050] Preferably, the modulation layer 104 may be composed of at least one metal oxide (MOX). Preferably, in this embodiment, the modulation layer 104 may be composed of four metal oxides, including ZnO, NiO, In2O3, and WO3. Preferably, the modulation layer 104 may also be composed of only two, three, five, or even more metal oxides (MOX). Preferably, the electrode 103, the sensing film 102, and the modulation layer 104 are arranged in an overlapping manner along the thickness direction of the substrate 101. Preferably, when the modulation layer 104 is provided at both the top and bottom of the substrate 101, the composition of the modulation layer 104 may be composed of different metal oxides to increase the pixel diversity in the olfactory odor array sensor 100. For example, the modulation layer 104 disposed at the top of the substrate 101 may be composed of ZnO and NiO in a gradient distribution; the modulation layer 104 disposed at the bottom of the substrate 101 may be composed of In2O3 and WO3 in a gradient distribution. Preferably, when the modulation layer 104 is disposed in the area of ​​the top or bottom of the substrate 101 in contact with the electrode 103, the modulation layer 104 located at the top or bottom of the substrate 101 can also be composed of different metal oxides in a gradient distribution. For example, the components of several strip-shaped modulation layers 104 corresponding to the first electrode at the top of the substrate 101 can be composed of two or more of ZnO, NiO, In2O3, WO3, and other metal oxides. Preferably, in the same olfactory odor array sensor 100, the components of several strip-shaped modulation layers 104 disposed in the area of ​​the top or bottom of the substrate 101 in contact with the electrode 103 can also be different, thereby further increasing the pixel diversity of the olfactory odor array sensor 100.

[0051] Preferably, the olfactory array sensor 100 of this embodiment can divide the substrate 101 into several pixels by a grid formed by the electrodes 103, and the size of a single pixel is determined by the intersection area of ​​the first electrode and the second electrode. Preferably, a single pixel contains several through holes, in other words, a single pixel contains several sensing films 102. Preferably, the sensing films 102 located in the intersection area of ​​the first electrode and the second electrode participate in sensing.

[0052] Preferably, the olfactory odor array sensor 100 can construct an array of 100 to 10,000 pixels by setting the number and arrangement of the electrodes 103, in order to mimic the diversity of biological olfactory receptors.

[0053] The sensing film 102 in these pixels comes into contact with the gas and undergoes an oxidation-reduction reaction, converting chemical information into electrical signals, which are then transmitted by the electrode 103.

[0054] Preferably, the olfactory array sensor 100 provided in this embodiment has 10,000 pixels, and the pixels are arranged in a 100×100 array, with each pixel having a size of 10×10μm. 2 .

[0055] Preferably, this embodiment provides an olfactory odor array sensor 100 with pixels arranged in a 10×10 array, wherein the electrodes 103 are arranged as follows: Figure 3 As shown. See also Figure 3 Preferably, the first electrode and the second electrode are orthogonally distributed in the thickness direction of the substrate 101. Preferably, Figure 3 The sensor size of a single pixel is 140×140μm. 2 Therefore, a sensor with 100 pixels occupies only about 4mm. 2 The area.

[0056] Preferably, the edges of the sensing film 102 in the pixel are in contact with the modulation layer 104 and the second electrode, respectively, so that the substrate 101 is electrically conductive along the thickness direction. Preferably, the olfactory array sensor 100 further includes a heating layer 106 capable of heating the sensing film 102. The heating layer 106 is disposed at the bottom of the second electrode, and an electrically insulating isolation layer 105 is disposed between the heating layer 106 and the second electrode.

[0057] Preferably, the heating layer 106 may be composed of a Pt heating electrode. Preferably, the insulating layer 105 electrically insulates the second electrode and the Pt heating electrode. Preferably, the insulating layer 105 may be made of SiO2 with a thickness ranging from 1 to 10 μm. Preferably, the heating layer 106 is used to heat the olfactory odor array sensor 100 to 200-500 degrees Celsius, so that the sensing membrane 102 can perform sensing at a highly sensitive temperature.

[0058] Preferably, in this embodiment, a modulation layer 104 is provided between the first electrode and the substrate 101 to adjust the carrier transport between the first electrode and the sensing film 102, so that each pixel in the olfactory odor array sensor 100 has different response characteristics to the gas, thereby increasing the pixel diversity in the olfactory odor array sensor 100.

[0059] Example 2

[0060] This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0061] This embodiment provides a method for fabricating an olfactory odor array sensor 100. See also... Figure 4 Preferably, the method for fabricating the olfactory odor array sensor 100 may include the following steps:

[0062] S1. Sensing material is deposited in the through holes arranged in the substrate 101 to form a sensing film 102 covering the inner wall of the through holes.

[0063] S2. Deposit a modulation layer 104 on the top and / or bottom of the substrate 101.

[0064] S3, Deposit electrode 103 for applying voltage to sensing membrane 102.

[0065] S4, Deposit an insulating layer 105 for electrical insulation.

[0066] S5. Deposit a heating layer 106 for heating the sensing membrane 102.

[0067] Preferably, the modulation layer 104 deposited on the top and / or bottom of the substrate 101 comprises at least one type of metal particles distributed in a gradient. Preferably, the modulation layer 104 is in contact with the sensing film 102, such that the sensing films 102 arranged in an array according to the vias are different, thereby enabling each pixel to have different response characteristics when detecting gas.

[0068] Preferably, the deposition of electrode 103 includes depositing a plurality of first electrodes on top of substrate 101 and depositing a plurality of second electrodes on bottom of substrate 101. Preferably, an insulating layer 105 is deposited at the bottom of the second electrodes, and a heating layer 106 is deposited at the bottom of the insulating layer 105.

[0069] See Figure 4 Preferably, the substrate 101 may be made of freestanding porous alumina or porous zirconia, or other porous ceramic substrates with uniform pores and a high aspect ratio of the pores.

[0070] The deposition of the sensing material can be performed using atomic layer deposition (ALD). Preferably, the specific method for depositing the sensing material into the vias arranged in an array on the substrate 101 to form the sensing film 102 using atomic layer deposition is as follows: a shadow mask with a window size of 4mm × 4mm is tightly covered on the substrate 101 to define the deposition area; tetramethylaminotin (C8H) is used... 24 Using N4Sn as a precursor, the temperature of the reaction chamber is maintained at 150°C, and SnO2 and Pd are deposited; thereby, a sensing film 102 composed of SnO2 and Pd covering the inner wall of the through hole is formed on the substrate 101.

[0071] Preferably, the deposition of the modulation layer 104 can be achieved using a sputtering device. Preferably, the present invention can deposit the modulation layer 104 on the top of the substrate 101, specifically by suspending a mask with an 8mm × 8mm square window on the top of the substrate 101. Utilizing the diffraction phenomenon of plasma flux at the edge of the mask window, a gradient film is formed during sputtering. Preferably, this embodiment allows for selection of mask heights for different materials. In this embodiment, a height of 2-10mm is selected to deposit four metal oxides in the order of ZnO, NiO, In2O3, and WO3. Preferably, when depositing the modulation layer 104, this embodiment allows the four materials to form a circular gradient distribution with different centers, constituting different mixed deposition modulation layers 104 on the top end face of the substrate 101. Preferably, when depositing the modulation layer 104, this embodiment can also set the deposition direction of the metal oxides to enhance the diversity of metal oxide distribution in the modulation layer 104.

[0072] Preferably, in this embodiment, two metal oxides selected from ZnO, NiO, In2O3, and WO3 are deposited along a first direction on the surface of substrate 101, and the other two metal oxides are deposited along a second direction on the surface of substrate 101. The first and second directions are not parallel, allowing two of the metal oxides to form a gradient distribution along the first direction, and the other two metal oxides to form a gradient distribution along the first direction. This enhances the mixing diversity of the four metal oxides on the surface of substrate 101, thereby increasing the diversity of the pixel's gas response characteristics. For each deposited metal oxide, the 90° angle of the hanging mask is adjusted to magnify the elemental distribution. After sputtering, the product is annealed at a high temperature of 200~600°C for 2~5 hours.

[0073] Preferably, this embodiment employs a multi-step SMAS method to fabricate a modulation layer 104 with a gradient distribution of metal particles. In this embodiment, by adjusting the distance between the suspending mask and the substrate 101, and the relative position of the mask on the substrate 101, after ALD deposition of the PdO / SnO2 or other sensing material layer, one or more metal oxides are deposited on the surface of the substrate 101 to form the modulation layer 104. The subsequent annealing process promotes further diffusion of metal cations and generates additional phases in the modulation layer 104, resulting in a gradient distribution of the concentration of metal cations in the modulation layer 104. Preferably, the metal cations are gradient-distributed in the modulation layer 104, so that the electrons (charge carriers) released by the reaction of the detected gas with adsorbed oxygen on the surface of the sensing film 102 are subject to different resistances when flowing through the modulation layer 104 in the pixel region. This results in different baseline resistances and response resistances for each pixel, thus making the response characteristics of each pixel to the detected gas different. This enables the integration of pixels with different response characteristics on the same olfactory odor array sensor 100, increasing the pixel diversity of the olfactory odor array sensor 100 and enhancing the recognition capability of the olfactory odor array sensor 100.

[0074] Preferably, in this embodiment, time-of-flight secondary ion mass spectrometry (ToF-SIMS) can be used to measure the spatial distribution of metal cations in the modulation layer 104, wherein the four cations (Zn) + Ni + In + W + Each of the elements in the modulation layer 104 has a gradient distribution of elemental concentration, thus constituting different pixels in the modulation layer 104. Preferably, the crystal phase of the modulation layer 104 is verified by X-ray diffraction (XRD) measurement, which includes the original four oxides (ZnO, NiO, In2O3, and WO3) and a new compound, including Zn, formed after a high-temperature annealing process at 200-600°C for 2-5 hours. x WO3 (monoclinic, JCPDS#43-1035), NiWO4 (monoclinic, JCPDS#51-225), In 2.2 WO3 (hexagonal, JCPDS#37-30) and In2O3 (ZnO) 17 (Rhombus, JCPDS#43-621).

[0075] Preferably, the secondary ion mass spectrometry (SIMS) depth profile is obtained by a spectrometer. Preferably, scanning electron microscopy (SEM) images of the surface and cross-section of the olfactory odor array sensor 100 are obtained using a scanning electron microscope, and transmission electron microscopy (TEM) images of individual channels in the substrate 101 are obtained using a transmission electron microscope.

[0076] The sensing film 102 has a significant impact on the final performance of the olfactory odor array sensor 100. Atomic layer deposition (ALD) can achieve uniform deposition of the sensing material layer within the vias of the substrate 101. Preferably, an annealing process at a high temperature of 200–600°C for 2–5 hours can further improve the crystallinity of SnO2 and Pd within the vias, enhancing the uniformity of the sensing film 102 and ensuring the final performance of the olfactory odor array sensor 100.

[0077] Preferably, the uniformity of the sensing film 102 can be verified by measuring the uniform distribution of Sn and Pd elements in a single sensing film 102. Preferably, this embodiment can be characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed the crystal structure and composition of the sensing material layer, confirming the tetragonal structure of SnO2 (JCPDS#41-1445) and PdO (JCPDS#41-1107), ultimately forming a PdO / SnO2 heterojunction sensing material layer. Preferably, the X-ray diffraction (XRD) is collected on an X'pert Pro diffractometer. Preferably, X-ray photoelectron spectroscopy (XPS) measurements are performed on a Kratos Axis Ultra DLD multi-technology surface analysis system. Preferably, a surface profilometer is used to characterize the thickness of the film. Preferably, the elemental mapping of the olfactory odor array sensor 100 is obtained by SEM and TEM attachment using energy dispersive spectroscopy (EDS).

[0078] Preferably, after annealing, Au with a thickness of 10-300 nm is deposited as electrode 103 on the top and bottom of the product using two thermal evaporations. Preferably, the deposition of electrode 103 includes depositing a first electrode on the top of the product in contact with the modulation layer 104 and depositing a second electrode on the bottom of the product in contact with the sensing film 102.

[0079] Preferably, for an olfactory odor array sensor 100 with pixels arranged in a 10×10 array, the electrode pattern of the shadow mask has 10 lines, with a line width and line spacing of 140 μm. Preferably, for an olfactory odor array sensor 100 with pixels arranged in a 20×20 array, the line width and spacing of the shadow mask are reduced to 100 μm. Preferably, for an olfactory odor array sensor 100 with pixels arranged in a 100×100 array, photolithography can be performed using photoresist on a Karl Suss MA6 system to fabricate electrodes 103 with a line width of 5~50 μm.

[0080] Preferably, during the sputtering deposition of materials, the present invention maintains a certain distance between the mask and the plane of the substrate 101, utilizing the directionality of material sputtering during magnetron sputtering to form a material content gradient on the sample surface, i.e., high content in the center and low content around the edges. Preferably, different materials are deposited sequentially at different center locations during material deposition, forming a superimposed mixture.

[0081] In this embodiment, when depositing the modulation layer 104 on the surface of the substrate 101, ink can also be prepared using metal oxide or its precursor, and inkjet coating process can be used to form a concentration distribution with high concentration in the middle and low concentration at the periphery. Different materials are coated sequentially at different central positions to form superimposed mixing, thereby depositing a modulation layer 104 with gradient changes in composition.

[0082] In this embodiment, when depositing the modulation layer 104 on the surface of the substrate 101, a slurry can be prepared using metal oxides or their precursors. The material content can be controlled by the number of dispensing operations using dispensing or inkjet printing processes. The material printing amount of each material in each pixel area can be pre-programmed to control the amount of each material printed, thereby forming a mixture of different materials in different proportions. Then, metal oxides with gradient composition are deposited on the surface of the substrate 101 to form the modulation layer 104.

[0083] Preferably, in this embodiment, when depositing the modulation layer 104 on the surface of the substrate 101, the modulation layer 104 can be deposited at both the top and bottom of the substrate 101, and the modulation layer 104 at the top or bottom of the substrate 101 can also be composed of different metal oxides in a gradient distribution. For example, In2O3 and WO3 in a gradient distribution can be deposited at the top of the substrate 101 to form the interface layer 104, while the modulation layer 104 at the bottom of the substrate 101 can be formed by depositing ZnO and NiO in a gradient distribution.

[0084] Example 3

[0085] This embodiment is a further improvement on Embodiments 1 and 2, and the repeated content will not be described again.

[0086] This embodiment provides an odor recognition system. The odor recognition system may include an odor array sensor 100, a signal readout circuit, and a processing module. Preferably, the odor array sensor 100 includes a plurality of pixels arranged in an array and a plurality of electrodes 103. Preferably, the electrodes 103 include a plurality of first electrodes disposed above the pixels and a plurality of second electrodes disposed below the pixels, wherein the plurality of first electrodes and the plurality of second electrodes form a grid when the plurality of pixels are disposed on a projected overlapping area. Preferably, the processing module is connected to the plurality of electrodes 103 through the signal readout circuit to obtain the resistance change generated by each pixel in response to the measured object, thereby generating a feature image of the measured object. Preferably, the pixels include a plurality of sensing films 102, and a modulation layer 104 for regulating carrier transport is disposed between the sensing films 102 and the electrodes 103. Preferably, the odor array sensor 100 used in the odor recognition system may be the odor array sensor 100 provided in Embodiment 1 or the odor array sensor 100 prepared by the preparation method in Embodiment 2.

[0087] Preferably, the odor recognition system may include an olfactory odor array sensor 100, a signal reading circuit, and a processing module. Preferably, the processing module is equipped with a neural network algorithm to process the electrical signal acquired by the signal reading circuit, thereby realizing the detection of the gas.

[0088] Preferably, in this embodiment, the olfactory odor array sensor 100 is bonded to a DIP or CLCC chip carrier using copper wire and silver paste, achieving reliable electrical contact and a superior signal-to-noise ratio. It is important to emphasize that the olfactory odor array sensor 100 is suspended after bonding, allowing for good gas transmission. The packaged olfactory odor array sensor 100 is integrated with the circuitry for reading electrical signals.

[0089] Preferably, the signal reading circuit performs ADC sampling on the olfactory odor array sensor 100 and then transmits the data to the processing module. Preferably, the processing module is equipped with a neural network algorithm to process the electrical signal acquired by the signal reading circuit, thereby realizing the detection of gas.

[0090] To address the technical problems of existing odor sensors in simulated mammalian olfaction systems, which lag behind the effectiveness of biological olfaction in terms of gas distinguishability, detection accuracy, and overall system power consumption, this embodiment provides an odor recognition system based on an olfactory odor array sensor 100. See [link to documentation]. Figure 5Preferably, the odor recognition system provided in this embodiment generates an electrical signal by reacting with the gas through the olfactory odor array sensor 100. The signal reading circuit acquires the electrical signal of the olfactory odor array sensor 100 and transmits it to the processing module equipped with a neural network algorithm to process the electrical signal acquired by the signal reading circuit, thereby realizing the detection of the gas.

[0091] The olfactory odor array sensor 100 of the present invention can be set with a number of pixels ranging from 100 to 10,000 to simulate the biological olfactory receptor that converts chemical information into electrical signals. Furthermore, the present invention increases the diversity of pixels in the olfactory odor array sensor 100 by setting a modulation layer 104 so that the carrier transport between each sensing membrane 102 in the pixel and the electrode 103 differs after reacting with the gas.

[0092] Preferably, the olfactory odor array sensor 100 of the present invention employs a 100×100 pixel array, and the size of a single olfactory odor array sensor 100 is 10×10µm. 2 Studies have shown that dogs have about 1,000 olfactory receptors compared to primates, giving them an amazing sense of smell. The number of pixels in the olfactory odor array sensor 100 used in this invention far exceeds the number of types of olfactory receptors in mammals.

[0093] Preferably, the present invention also studies and verifies the integration effect of olfactory odor array sensors 100 integrating arrays of sensing films 102 of different sizes, such as olfactory odor array sensors 100 with 10×10 and 20×20 sensing film 102 arrays. See also Figure 5 G. Preferably, by utilizing the pixel diversity of the olfactory odor array sensor 100, the odor recognition system provided by the present invention can generate a set of feature patterns for different gases or odor molecules.

[0094] Preferably, this invention utilizes a neural network algorithm to verify the high recognition capability (prediction accuracy up to 99.04%) of the olfactory odor array sensor 100 for gases with different concentrations under different humidity backgrounds, including acetone, carbon monoxide, ethanol, formaldehyde, nitrogen dioxide, toluene, hydrogen, and isobutylene, and confirms that using more pixels can achieve even higher accuracy. More importantly, this invention further verifies the odor recognition system's accurate identification capability for components and concentrations in mixed gases.

[0095] Example 4

[0096] This embodiment is a further improvement on Embodiments 1, 2 and 3, and the repeated content will not be repeated.

[0097] This embodiment provides a robot. The robot is equipped with a target recognition system that combines visual and olfactory perception. Preferably, the target recognition system includes: at least one olfactory sensor, at least one visual sensor, and a controller. The olfactory sensor and the visual sensor are respectively signal-connected to the controller. The olfactory sensor is capable of determining first attribute information of the target object by olfactory recognition. The visual sensor is capable of determining second attribute information of the target object by visual recognition. The controller is capable of determining the object type of the target object based on the first attribute information determined by the olfactory sensor and / or the second attribute information determined by the visual sensor.

[0098] Preferably, the olfactory sensor can be the olfactory odor array sensor 100 provided in Example 1 or the olfactory odor array sensor 100 prepared by the preparation method in Example 2. Preferably, the target recognition system can include an odor recognition subsystem and an image recognition subsystem. Preferably, the odor recognition subsystem can be the odor recognition system in Example 3.

[0099] See Figure 6 Preferably, in this embodiment, an olfactory odor array sensor 100 is installed on a robot dog. The olfactory odor array sensor 100 is connected to the robot dog's controller, enabling the robot dog to have an olfactory function.

[0100] Preferably, Figure 6 D indicates that the configured odor recognition system is installed on the quadruped robot to distinguish objects in the blind box; Figure 6 E represents the computer vision (i.e., camera) recognition result; Figure 6 F represents the recognition result of the odor recognition system; Figure 6 G represents the real-time recording of the resistance signal of a certain pixel.

[0101] Preferably, in order to demonstrate the potential of the olfactory odor array sensor 100 of the present invention in advanced robotics, such as Figure 6 As shown in Figure D, the present invention installs an odor recognition system based on an olfactory odor array sensor 100 on a robot dog to give the robot an olfactory function.

[0102] See Figure 7 Preferably, to examine the overall functionality of the robot dog, this invention sets up an experiment to achieve blind box recognition by fusing the vision and olfaction functions of a quadruped robot. Specifically, this invention designs two experiments: five identical boxes are placed in the test area, two of which contain objects with different scents (red wine and oranges).

[0103] See Figure 6 E. Visual sensors (cameras) alone are insufficient to distinguish the differences between these boxes. See also Figure 6F, preferably, when an olfactory function (an odor recognition system based on an olfactory odor array sensor 100) is introduced, the robot can visually recognize the shape of the boxes and move from one box to another, and then distinguish the internal objects (red wine, oranges, or empty) through its olfactory ability. Figure 6 G describes the real-time signal of a typical pixel in the olfactory odor array sensor 100 of this invention. In such miniature reconnaissance missions, through the fusion of vision and smell, robots can effectively and accurately identify objects in blind boxes. This vividly demonstrates the enormous application potential of olfactory robots in fields such as security, counter-terrorism, and disaster relief.

[0104] like Figure 6 D and Figure 7 As shown, the odor recognition system developed in this invention is fixed to the head of a quadruped robot. In the experiment, five boxes of the same shape and size were arranged in a row in a specific location. The robot first observed the boxes from a distance of 4 meters using its built-in camera and target detection algorithm. The box target detection described in this invention is implemented using the OpenCV2 library. It mainly uses seven functions: ColorDetectorMask, GaussianBlur, threshold, getStructuringElement, morphologyEx, Erode, and Dilate. In the ColorDetectorMask function, the detection is first performed based on the color of the box in the HSV (Hue, Saturation, Value) color space. After obtaining the mask of the box in the image, the image is further denoised and then binarized. Preferably, the closed shape of the box in the image is obtained using the getStructureElement and morphologyEx functions. For the implementation of the olfactory function, this embodiment uses the same algorithm as the odor recognition in the previous embodiment, collecting real-time data at a frequency of 1Hz and displaying the recognition results in real time.

[0105] Preferably, this embodiment demonstrates the ability to fuse vision and smell for small reconnaissance missions on a quadrupedal mobile robot, which clearly reveals the application potential of the odor recognition system of the present invention.

[0106] The olfactory odor array sensor 100, which integrates pixels with different response characteristics, provides performance comparable to or even higher than that of the mammalian olfactory system. Therefore, the olfactory odor array sensor 100 provided by the present invention is suitable for intelligent applications of olfactory function.

[0107] This embodiment provides a quadrupedal mobile robot that integrates an olfactory odor array sensor 100, i.e., a robot dog that integrates an olfactory odor array sensor 100, realizing the fusion of the robot's sense of smell and vision, and giving the robot dog the ability to distinguish odors in blind boxes, which further paves the way for the application of complex robots in various types of scenarios.

[0108] Improving the level of intelligence is an inevitable trend in the development of advanced robotics technology, and sensor technology is one of the foundations for its realization. Multi-sensor fusion can combine information acquired by different sensors to provide a more accurate and reliable perception of the external environment, thereby improving the rationality of robot decision-making. Although existing technologies have integrated many different types of sensors with robots, such as temperature sensors, tactile sensors, sound sensors, and various light sensors, olfactory sensors are rarely used. In fact, equipping robots with olfactory capabilities can make them more intelligent and significantly expand their application range.

[0109] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. Throughout the text, features introduced by "preferred" are merely optional and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time. This specification contains multiple inventive concepts. Phrases such as "preferred," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept.

Claims

1. An olfactory odor array sensor, characterized by, The olfactory odor array sensor includes: A substrate (101) with an array of through holes. A sensing membrane (102) is disposed on the inner wall of the through hole, which changes its resistance by reacting with the object being measured. An electrode (103) that applies a voltage to the sensing membrane (102); Modulation layer (104) for adjusting carrier transport between the electrode (103) and the sensing membrane (102). The electrode (103), the sensing film (102) and the modulation layer (104) are arranged to overlap along the thickness direction of the substrate (101). The modulation layer (104) is disposed between the electrode (103) and the sensing film (102). The modulation layer (104) contains at least one type of metal particles distributed in a gradient.

2. The olfactory odor array sensor of claim 1, wherein, The electrode (103) includes a plurality of first electrodes disposed on the top of the substrate (101) along the thickness direction of the substrate (101) and a plurality of second electrodes disposed on the bottom of the substrate (101); The overlapping area of ​​the projections of the first electrode and several second electrodes in the thickness direction of the substrate (101) covers several of the sensing films (102) to form pixels for sensing.

3. The olfactory odor array sensor according to claim 2, characterized in that, The modulation layer (104) includes one of the following: the top end face of the substrate (101), the bottom end face of the substrate (101), the contact area between the top of the substrate (101) and the first electrode, and the contact area between the bottom of the substrate (101) and the second electrode.

4. The olfactory odor array sensor of claim 3, wherein, The first electrode and the modulation layer (104) are provided with openings that match the through holes to form an airflow channel, so that the object to be measured can contact the sensing membrane (102).

5. The olfactory odor array sensor of claim 4, wherein, The edge of the sensing film (102) contacts the modulation layer (104) and the second electrode respectively, so that the substrate (101) is electrically conductive along the thickness direction.

6. The olfactory odor array sensor according to claim 5, characterized in that, The olfactory odor array sensor also includes a heating layer (106) capable of heating the sensing membrane (102); the heating layer (106) is disposed at the bottom of the second electrode, and an electrically insulating isolation layer (105) is disposed between the heating layer (106) and the second electrode.

7. A method of preparing an olfactory odor array sensor, characterized by, The preparation method includes: Sensing material is deposited in the vias arranged in an array on the substrate (101) to form a sensing film (102) covering the vias. A modulation layer (104) is deposited on top of the substrate (101). The modulation layer (104) is disposed between the electrode (103) and the sensing membrane (102) for regulating carrier transport between the electrode (103) and the sensing membrane (102). The modulation layer (104) contains at least one type of metal particles in a gradient distribution. The modulation layer (104) is in contact with the sensing membrane (102), which makes the sensing membranes (102) arranged in an array based on the through holes different.

8. The preparation method according to claim 7, characterized in that, The preparation method further includes: Deposit electrodes (103) for applying voltage to the sensing membrane (102); Deposit an insulating layer (105) for electrical insulation; Deposit a heating layer (106) for heating the sensing membrane (102). The deposition of the electrode (103) includes depositing a plurality of first electrodes on the top of the substrate (101) and depositing a plurality of second electrodes on the bottom of the substrate (101); The isolation layer (105) is deposited at the bottom of the second electrode, and the heating layer (106) is deposited at the bottom of the isolation layer (105).

9. An odor recognition system characterized by, The odor recognition system includes an olfactory odor array sensor (100), a signal reading circuit, and a processing module as described in any one of claims 1 to 6; The olfactory odor array sensor (100) includes a plurality of pixels arranged in an array and a plurality of electrodes (103), wherein the electrodes (103) include a plurality of first electrodes disposed above the pixels and a plurality of second electrodes disposed below the pixels, and the plurality of first electrodes and the plurality of second electrodes form a grid by arranging the plurality of pixels on a projected overlapping area. The processing module connects to several electrodes (103) through the signal reading circuit to obtain the resistance change generated by each pixel in response to the object being measured, and then generates a feature image of the object being measured.

10. A robot, characterized in that The robot is equipped with a target recognition system that combines visual and olfactory perception. The target recognition system includes: At least one olfactory sensor is capable of determining first attribute information of a target object by means of olfactory recognition, wherein the olfactory sensor includes an olfactory odor array sensor (100) as described in any one of claims 1 to 6. At least one visual sensor is capable of determining the second attribute information of the target object through visual recognition; The controller is able to determine the object type of the target object based on the first attribute information determined by the olfactory sensor and / or the second attribute information determined by the visual sensor.

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