Glass three-dimensional gas transport path encoding chip and volatile organic compound detection method

Abstract

This invention discloses a glass three-dimensional gas transport path encoding chip and a method for detecting volatile organic compounds (VOCs). The chip includes a transparent glass or quartz substrate, a gas inlet, at least two three-dimensional paths written by an ultrafast laser, multiple gas release ports, and a gas sensor array. Each path has different structural features such as length, cross-section, or bends, allowing VOCs introduced in a single injection to generate different diffusion, residence, and delay histories during parallel transport. The sensor array reads these histories to generate a spatiotemporal response encoding spectrum, eliminating the need for sequential opening and closing control of multiple release ports. This invention utilizes the internal three-dimensional structure of the glass to generate odor recognition information and is applicable to fields such as VOC identification, complex odor classification, and environmental monitoring.

Description

Technical Field

[0001] This invention belongs to the fields of gas sensing, volatile organic compound detection, glass microfluidic chips, three-dimensional laser micro-nano processing, and biomimetic olfactory information encoding technology. Specifically, it relates to a chip, system, and detection method that uses ultrafast lasers to write three-dimensional gas transport paths inside glass, quartz, or other transparent substrates, and converts volatile organic compound samples into spatiotemporal response encoding spectra that can be read by a sensor array by utilizing the differences in diffusion, residence, delay, release, and arrival history of different paths. Background Technology

[0002] Volatile organic compounds (VOCs) are widely present in scenarios such as food safety, grain storage and transportation, environmental monitoring, industrial process control, fermentation processes, and health-related samples. Existing electronic noses or gas sensing arrays typically rely on a cross-response array composed of multiple different sensitive materials to obtain odor fingerprints through differences in material chemoselectivity. However, multi-material arrays often suffer from problems such as complex material preparation, poor channel consistency, long-term drift, humidity interference, and insufficient batch-to-batch repeatability.

[0003] Existing microchromatographic or microfluidic gas analysis chips typically focus on component separation and quantitative detection, requiring strict matching of column structure, stationary phase, carrier gas, temperature control, and detector. For tasks such as rapid screening, state identification, and abnormal odor early warning, complete peak-by-peak separation is not the only necessary condition; more importantly, it is crucial to be able to transform complex odors into stable, learnable, and distinguishable response spectra.

[0004] Some gas sensing systems have already modified the gas flow field by adjusting the external cavity geometry, airflow boundary conditions, outlet layout, or valve opening and closing status to change the response mode of the sensing array. However, these solutions typically rely on the macroscopic flow channels of metal or polymer cavities, the dynamic or static configuration of outlets, and external valve-controlled boundaries, with their primary encoding source being the cavity boundary conditions or outlet status.

[0005] Ultrafast laser writing technology can directly construct three-dimensional microchannels, folded paths, different depth levels, vertically connected structures, expansion cavities, and microcavity networks within transparent substrates such as glass and quartz. If these three-dimensional paths are used to modulate the transport of gas-phase volatile molecules, the diffusion, residence, and arrival history of molecules can be actively controlled using structural parameters such as path length, channel cross-section, bending structure, expansion-contraction structure, depth level, and release position before they enter the sensing array.

[0006] Therefore, it is necessary to propose a glass three-dimensional path coding chip that is different from the outlet opening and closing coding and the stainless steel cavity boundary coding. This chip allows the same volatile organic compound sample to propagate in parallel through multiple laser writing paths inside the transparent substrate, and is acted upon by multiple release ports to form a spatiotemporal response coding map that defines the path structure. Summary of the Invention

[0007] The purpose of this invention is to provide a glass three-dimensional gas transport path encoding chip and a method for detecting volatile organic compounds, in order to solve the problems of existing electronic noses that mainly rely on differences in sensitive materials, existing microchromatography that pursues peak-by-peak separation and is therefore complex, and existing gas flow boundary encoding platforms that rely on the opening and closing of the gas outlet or macroscopic cavity structure.

[0008] This invention writes multiple three-dimensional gas paths with different transport functions inside a transparent glass or quartz substrate, allowing VOC samples to enter different paths in parallel during a single injection process, generating different diffusion, residence, delay, release, and arrival histories. These histories are then synchronously read by sensor arrays corresponding to multiple release ports, constructing a spatiotemporal response coding map composed of path dimension, release position dimension, sensor channel dimension, and time dimension.

[0009] The specific technical solution for achieving the objective of this invention is as follows:

[0010] A glass three-dimensional gas transport path encoding chip, characterized by comprising: a transparent glass or quartz substrate; at least one gas inlet disposed on the transparent glass or quartz substrate; at least two three-dimensional gas transport paths formed by ultrafast laser writing inside the transparent glass or quartz substrate; a plurality of gas release ports communicating with the at least two three-dimensional gas transport paths; and a gas sensing array arranged corresponding to the plurality of gas release ports; a sealing gasket is disposed between the transparent glass or quartz substrate and the gas sensing array, the sealing gasket having through holes corresponding to the plurality of gas release ports; wherein, the at least two three-dimensional gas transport paths have different path lengths, channel cross-sectional areas, bending structures, expansion cavities, local contraction sections, depth levels, vertical connection structures, three-dimensional folding structures, branch structures, release positions, or inner surface states, so that volatile organic compounds entering the gas inlet generate different diffusion, residence, delay, release, or arrival histories in different three-dimensional gas transport paths, and the gas sensing array reads these histories to form a spatiotemporal response encoding spectrum.

[0011] Furthermore, the transparent glass or quartz substrate is borosilicate glass, quartz glass, fused silica, or transparent ceramic; the ultrafast laser is a femtosecond laser, a picosecond laser, or a combination thereof; the at least two three-dimensional gas transport paths are formed sequentially by laser writing, etching, cleaning, annealing, and surface treatment processes; the at least two three-dimensional gas transport paths include straight paths, long straight paths, serpentine paths, spiral paths, labyrinth paths, expansion-contraction paths, three-dimensional folding paths, branching paths, and microcavity array paths; at least one of the at least two three-dimensional gas transport paths includes a local expansion cavity and a local contraction section, used to control the residence time, peak width, release rate, or recovery process of volatile organic compounds in the path.

[0012] Furthermore, the at least two three-dimensional gas transport paths are distributed at different depth levels inside the transparent glass or quartz matrix and are connected by vertical connecting channels. Their three-dimensional gas transport paths intersect in spatial projection but are not connected to each other.

[0013] Furthermore, the multiple gas release ports are arranged in a one-dimensional linear array, a two-dimensional matrix array, a ring array, a radial array, or an irregular array, and correspond to multiple sensing sites in the gas sensing array; the at least two three-dimensional gas transport paths are connected and work in parallel during a single sample injection process, and can form multi-path spatiotemporal response coding without relying on the time-sequential opening or closing of multiple gas release ports.

[0014] Furthermore, the gas sensing array is a resistive, impedance, capacitive, current-based, optical, mass-based, or electrochemical sensing array; the sensing units in the gas sensing array use the same or homologous sensitive materials; the sensitive materials include carbon materials, graphene, reduced graphene oxide, conductive polymers, metal oxides, metal-organic framework materials, coordination polymers, and composite porous materials.

[0015] Furthermore, a gas diffusion metasurface formed by ultrafast laser writing is disposed inside or near the surface region of the transparent glass or quartz substrate. The gas diffusion metasurface includes micropore arrays, microcavity arrays, microgroove arrays, spiral channels, radial gradient channels, striped anisotropic channels, and fractal diffusion networks.

[0016] Furthermore, at least one of the at least two three-dimensional gas transport paths includes an inlet focusing region, a retention or interaction region, and a branch release region.

[0017] Furthermore, the transparent glass or quartz substrate is pressed and sealed to the sealing gasket and the gas sensing array by an external clamping frame, clamp, elastic clamping member or external threaded fastener, and the external threaded fastener does not pass through the stress area of ​​the transparent glass or quartz substrate.

[0018] A volatile organic compound (VOC) detection system based on the aforementioned glass three-dimensional gas transport path encoding chip includes a VOC sample introduction module, a laser-written glass three-dimensional gas transport path encoding chip module, a signal acquisition module, a data processing and recognition module, and an output result module. The VOC sample introduction module provides sample gas to the gas inlet. The laser-written glass three-dimensional gas transport path encoding chip module has its gas input terminal connected to the VOC sample introduction module. This module is constructed by sequentially and hermetically sealing a transparent glass or quartz substrate, a sealing gasket, and a gas sensor array. It receives sample gas from the VOC sample introduction module, allowing VOCs to be transported in parallel through multiple three-dimensional gas transport paths within the transparent glass or quartz substrate and undergoing physical transport modulation. Subsequently, the VOCs are released through the sealing gasket to the corresponding gas sensor. The system comprises a gas sensing array that converts volatile organic compound (VOC) samples into multi-channel sensing responses; a signal acquisition module electrically connected to the gas sensing array in the laser-written glass three-dimensional gas transport path encoding chip module, used to synchronously receive and acquire multi-channel time response signals of resistance, impedance, current, voltage, or capacitance output from multiple sensing sites; a data processing and recognition module communicatively connected to the signal acquisition module, used to extract peak value, response area, peak time, rise time, half-maximum width, recovery time, inter-path response ratio, inter-path correlation, or spatial distribution characteristics, and construct a spatiotemporal response encoding map based on these characteristics for dimensionality reduction, classification, or regression analysis; and an output result module connected to the data processing and recognition module, used to receive the recognition results and visualize the types, concentration ranges, or sample categories of VOCs.

[0019] A method for detecting volatile organic compounds (VOCs) based on a glass three-dimensional gas transport path encoding chip includes the following steps: introducing a VOC sample into a gas inlet on a transparent glass or quartz substrate, allowing the VOC sample to be transported in parallel through at least two three-dimensional gas transport paths; releasing the VOCs modulated by the three-dimensional gas transport paths to corresponding gas sensing arrays through multiple gas release ports; synchronously acquiring multi-channel time response signals from the gas sensing arrays; constructing a spatiotemporal response encoding map of the VOCs based on the multi-channel time response signals; and identifying VOCs or samples containing VOCs based on the spatiotemporal response encoding map. The spatiotemporal response encoding map includes path dimensions, release location dimensions, sensing channel dimensions, and time dimensions. The VOCs include alcohols, aldehydes, ketones, acids, esters, aromatic compounds, sulfur-containing compounds, nitrogen-containing compounds, or mixtures thereof; the samples containing VOCs include grains, food, tea, tobacco, traditional Chinese medicine, ambient air, fermented samples, and moldy samples. The identification includes principal component analysis, linear discriminant analysis, support vector machine, random forest, convolutional neural network, partial least squares regression, cluster analysis, or a combination thereof.

[0020] Technical features of the present invention

[0021] Transparent in-matrix in-situ structure: The gas transport path is located inside a transparent matrix such as glass, quartz or fused silica, rather than relying on a metal top cavity recess or external gas outlet layout.

[0022] 3D path encoding: Different path transport functions are formed by path length, number of bends, expansion cavity, local contraction segment, depth level and 3D fold structure.

[0023] Parallel multi-path release: After the same injection, the sample simultaneously reaches different release ports through multiple paths and acts on the corresponding sensing sites.

[0024] Array reading: The sensor array synchronously reads the response curves modulated by different paths, forming a spatiotemporal encoded map of "path-location-time-response".

[0025] Valveless preferred solution: In the preferred embodiment, there is no need to dynamically control the opening and closing of multiple air outlets, thereby reducing system complexity and dead volume of the air path.

[0026] Scalable structure: It can be further formed into gas diffusion metasurfaces, three-dimensional multi-depth networks or micro pre-separation-release paths for odor coding tasks of varying complexity.

[0027] Beneficial effects

[0028] 1. Using the three-dimensional path inside the glass as a gas transport encoder, a novel structural coding method is provided that is different from the gas outlet opening and closing coding and ordinary cavity boundary coding.

[0029] 2. Multiple paths can work in parallel, allowing for the acquisition of response signals modulated by multiple paths in a single sample injection, thereby increasing the information dimension and shortening the testing process.

[0030] 3. It does not require the complete peak-by-peak separation in the traditional microchromatographic sense, but achieves rapid identification through the spatiotemporal response spectrum after path modulation, which is suitable for odor state judgment and complex sample classification.

[0031] 4. Glass or quartz substrates have advantages such as solvent resistance, corrosion resistance, low background interference, washability, and reusability, making them suitable for constructing highly stable gas transport coding chips.

[0032] 5. It can be coupled with sensing arrays of the same or homologous sensitive materials, enabling some identification information to be generated by physical paths, reducing dependence on the chemical selectivity of multiple materials.

[0033] 6. It can form design rules between structural parameters, path transport functions, response characteristics, and identification performance, providing a basis for subsequent large-scale, low-cost structural replication. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall system structure of the present invention;

[0035] Figure 2 A schematic diagram of a gas transport coding chip with one inlet, five paths, and five sensing points;

[0036] Figure 3 A schematic diagram of a representative gas transport path;

[0037] Figure 4 This is a schematic diagram of a three-dimensional multi-depth gas transport network structure;

[0038] Figure 5 This is a schematic diagram of a gas diffusion metasurface structure.

[0039] Figure 6 This is a schematic diagram of the micro pre-separation-release path encoding chip structure;

[0040] In the diagram: 1-VOC sample injection module; 2-Transparent glass or quartz substrate; 3-Sealing gasket; 4-Gas sensor array; 5-Signal acquisition module; 6-Data processing and recognition module; 7-Output result module. Detailed Implementation

[0041] The specific embodiments of the present invention will be described below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Within the framework of this invention, those skilled in the art can make equivalent substitutions or combinations regarding the number of paths, path dimensions, release port arrangement, sensor array type, sealing method, and data processing method.

[0042] In this invention, the "path transport function" refers to the concentration-time output relationship of a three-dimensional gas transport path to an input gas pulse or continuous gas flow. This relationship can be affected by factors such as path length, cross-sectional area, bends, expansion cavities, surface conditions, depth levels, and release locations.

[0043] Example 1: System Overall Structure

[0044] like Figure 1As shown, this embodiment provides a volatile organic compound (VOC) detection system based on a glass three-dimensional gas transport path encoding chip. The overall system architecture, from left to right, consists of a VOC sample introduction module 1, a laser-written glass three-dimensional gas transport path encoding chip module (assembled from a transparent glass or quartz substrate 2, a sealing gasket 3, and a gas sensor array 4), a signal acquisition module 5, a data processing and recognition module 6, and an output result module 7. The specific structure and signal flow are as follows:

[0045] The VOC sample introduction module 1 is equipped with a "VOC" inlet and a downward exhaust outlet for precisely introducing and controlling the gas from the sample to be tested. Its right-side output is directly connected to the subsequent transparent glass or quartz substrate 2 via a gas pipeline to provide the gas source for the system.

[0046] The laser-written glass three-dimensional gas transport path encoding chip module is the core physical modulation unit of the system. Structurally, it is composed of a transparent glass or quartz substrate 2, a sealing gasket 3, and a gas sensing array 4, assembled in a gas-tight manner from left to right. The transparent glass or quartz substrate 2 contains a three-dimensional spatial gas transport path network constructed by ultrafast laser writing. Sample gas introduced by the VOC sample introduction module 1 enters multiple three-dimensional paths for parallel transmission, completing physical modulation processes such as diffusion, retention, and delay. The sealing gasket 3 is sandwiched between the transparent glass or quartz substrate 2 and the gas sensing array 4, serving to isolate cross-contamination and gas-tight coupling, ensuring that the modulated gas is accurately guided to the sensing area. The surface of the gas sensing array 4 integrates multiple gas sensing units arranged in a matrix (as shown in the figure, a 4×4 array), used to receive the modulated gas passing through the sealing gasket 3, converting the spatial and temporal changes in gas concentration into multi-channel sensing signals. A ribbon cable connection socket is provided on the side of the array.

[0047] The input of signal acquisition module 5 is electrically connected to the interface of gas sensor array 4 via a multi-core ribbon cable. This module integrates amplifiers, filters, and other circuit units to synchronously receive multi-channel signals output from gas sensor array 4 and record the raw time response signals such as resistance, impedance, current, voltage, capacitance, or optical properties at the corresponding sensing sites. Data processing and recognition module 6 establishes a data communication connection with signal acquisition module 5. This module incorporates a processor (CPU) and machine learning algorithm units such as neural networks to receive the acquired raw response signals and sequentially perform baseline correction, filtering, normalization, and feature extraction operations. Subsequently, it performs dimensionality reduction, classification, or regression analysis decoding based on the extracted spatiotemporal response encoded spectrum. Output result module 7 connects to data processing and recognition module 6 and appears as a smart terminal or dashboard with a visual display screen. After receiving the decoding results, this module displays the specific types, concentration ranges, or sample categories of volatile organic compounds on the screen using intuitive charts such as molecular information, bar charts, and line graphs.

[0048] Example 2: Glass three-dimensional gas transport path encoding chip with one inlet, five paths, and five sensing points.

[0049] like Figure 2 As shown, this embodiment provides a glass three-dimensional gas transport path encoding chip with one inlet, five paths, and five release ports. In the overall assembly structure, the chip is composed of a transparent glass or quartz substrate 2, a sealing gasket 3, and a gas sensing array 4 stacked in an airtight manner from top to bottom.

[0050] A unified gas inlet is located at the top center of the transparent glass or quartz substrate 2 for receiving external samples. The gas inlet extends downwards and communicates with a common distribution channel inside the transparent glass or quartz substrate 2. This common distribution channel extends to both sides and further communicates with five parallel three-dimensional gas transport paths P1, P2, P3, P4, and P5.

[0051] These five paths have distinct structural features: P1 is a straight path on the left; P2 is a long straight path; P3 is a serpentine path, which increases the gas travel distance through multiple consecutive bends in a plane; P4 is an expansion-contraction path, consisting of alternating wide chambers and narrow channels connected in series; and P5 is a three-dimensional folding path on the right, which involves multiple folds in the spatial depth direction of the transparent glass or quartz substrate 2. The ends of the five paths (P1 to P5) are perpendicularly connected to their respective release outlets.

[0052] Regarding the interlayer fit, the sealing gasket 3 in the middle layer has five through holes that correspond one-to-one with the release outlets of the upper path; the gas sensing array 4 in the bottom layer is arranged in a one-dimensional linear pattern and contains five independent sensing points. The five release outlets at the bottom of the transparent glass or quartz substrate 2 pass through the corresponding through holes on the sealing gasket 3 and are precisely aligned vertically with the five sensing points S1, S2, S3, S4 and S5 on the bottom gas sensing array 4.

[0053] During testing, the sample enters through a single gas inlet and is simultaneously distributed to five paths, P1 to P5, in the same injection process. Due to the different internal spatial structures and transport functions of each path (P1 to P5), the gas exhibits varying diffusion, retention, and delay effects during transport. When the gas, after physical transport modulation, is finally released to its corresponding sensing sites S1 to S5, it displays different arrival times, peak widths, exposure intensities, and recovery processes, thus forming a five-path spatiotemporal coded response spectrum on the gas sensing array 4, defined by path, location, and time.

[0054] Example 3: Representative Path Structure

[0055] like Figure 3 As shown, the cross-section and spatial orientation of the three-dimensional gas transport path exhibit seven representative configurations. Each configuration clearly has a gas "inlet" and a gas "outlet" at both ends, with specific structural features as follows:

[0056] Figure 3 (a) shows a straight path: gas enters from the left "inlet" and is directly transmitted to the right "outlet" through a single, straight channel of equal width, without any bends or changes in width. This minimizes airflow resistance and can be used as a reference for rapid response.

[0057] Figure 3 (b) shows a long straight path: its basic shape is the same as that of a straight path, but the middle of the channel has a break ellipsis symbol to indicate physical truncation, indicating that the path has an extremely long straight distance in actual physical extension, which is mainly used to introduce a significant path length delay without changing the fluid shape.

[0058] Figure 3 (c) shows a serpentine path: after entering from the left "inlet," the gas undergoes multiple consecutive "U"-shaped up-and-down bends within a single two-dimensional plane, finally flowing out from the right "outlet." This structure effectively increases the gas flow distance, the number of bends, and the residence time within a limited substrate projection area.

[0059] Figure 3(d) shows the spiral path: after the gas is introduced through the edge "inlet", the channel spirals continuously in a two-dimensional plane, eventually leading out to the right "outlet". This structure can provide long-range lateral expansion and centrifugal dispersion effects;

[0060] Figure 3 (e) shows the maze path: within a rectangular outline area, the passages from the left "entrance" to the right "exit" form a right-angled network, containing multiple non-connected blind ends and multiple detours, using complex geometric obstacles to increase the probability of airflow collision and dwell time;

[0061] Figure 3 (f) shows the expansion-contraction path: the channel width varies non-uniformly and symmetrically. After the gas enters from the left capillary "inlet," the middle of the channel smoothly expands laterally to both sides, forming a wide, axisymmetric chamber, and then gradually contracts and narrows again, connecting to the right capillary "outlet." This alternating wide and narrow structure creates local deceleration retention and re-acceleration release regulation of the airflow;

[0062] Figure 3 Figure (g) shows the three-dimensional folding path: a multi-layered layout in three-dimensional space. After entering the horizontal channel from the "entrance" on the left side of the top layer, the gas descends through the vertical channel to deeper levels; the vertical dashed lines in the figure illustrate the projection alignment between the different depth levels. The gas zigzags and sinks between multiple horizontal planes at different heights, finally exiting from the "exit" on the right side of the bottom layer, forming an extremely complex arrival history through folding in the spatial depth direction.

[0063] Example 4: Three-dimensional multi-depth gas transport network

[0064] like Figure 4 As shown, in some embodiments, this embodiment provides a gas transport coding chip structure including a three-dimensional network. The structure, spatially arranged from top to bottom, consists of a top gas inlet, a centrally located transparent glass or quartz substrate 2, and a bottom gas sensing array 4.

[0065] The three-dimensional gas transport path within the transparent glass or quartz substrate 2 is not limited to a single plane, but rather distributed across multiple spatial depth levels within the substrate. The figure clearly delineates and marks three representative depth levels: shallow z1, intermediate z2, and deep z3, using horizontal dashed lines. After entering through a single gas inlet at the top, the sample gas undergoes horizontal transport and branching within each level (z1, z2, z3); ​​while the airflow across different depth levels is connected vertically through vertically distributed "vertical connecting channels." This multi-level three-dimensional design ensures that even if paths at different levels intersect in a two-dimensional top-view projection, they remain independent and do not interfere with each other in three-dimensional physical space, thus enabling the construction of a highly complex three-dimensional path network within a limited chip substrate area.

[0066] Multiple independent gas release ports extend vertically downwards from the bottom surface of the transparent glass or quartz substrate 2. Directly below these ports, a gas sensing array 4 is arranged in parallel. The surface of this gas sensing array 4 integrates 20 independent sensing points (numbered S1 to S20 in the figure), forming a 5×4 sensor array arrangement with 5 columns horizontally and 4 rows vertically. The vertical dashed arrows in the figure accurately illustrate the one-to-one vertical spatial alignment between each release port at the bottom of the transparent glass or quartz substrate and its corresponding sensing point below (such as S1, S2, S3, etc.).

[0067] During operation, the VOC gas to be measured undergoes cross-layer transport within a multi-layered three-dimensional network. Due to the differentiated physical diffusion and retention at different depth levels (z1, z2, z3), different total transport lengths, and different three-dimensional folding methods, completely different gas concentration-time output characteristics are ultimately formed above each release port. This allows the 5×4 gas sensing array below to synchronously capture a complex response tensor defined by four dimensions: spatial depth, transport path, physical location, and time.

[0068] Example 5: Gas Diffusion Metasurface

[0069] See Figure 5 As shown in Figure (a), in some embodiments, a three-dimensional gas diffusion metasurface chip assembly structure is provided. The structure is composed of a top gas inlet, a transparent glass or quartz substrate 2, and a bottom gas sensing array 4 stacked in an airtight manner from top to bottom.

[0070] The transparent glass or quartz substrate 2 contains gas diffusion metasurface structures formed by laser direct writing, distributed within its interior or near-surface region. During operation, the gas to be measured is vertically injected downwards into the transparent glass or quartz substrate 2 through the top gas inlet. Upon entering the substrate, the gas undergoes lateral flow field expansion and structured redistribution within a horizontal plane along the designed channel trajectory within a dense network of micropores and microchannels. Subsequently, the laterally modulated gas penetrates the bottom surface of the substrate, completing gas redistribution and being released vertically downwards, precisely covering the surfaces of the sensor units arranged in a one-dimensional linear pattern on the gas sensing array 4 below, thereby constructing a preset spatial concentration field on the gas sensing array.

[0071] Figure 5 Images (b) to (e) show the planar topological configurations (top view) of four representative gas diffusion metasurfaces within the transparent glass or quartz substrate 2, and the corresponding cross-sectional physical relationships (bottom view) of the vertical release of gas from the micropores / microchannels within the transparent glass or quartz substrate 2 to the lower gas sensing array 4. The specific flow field modulation characteristics of the four structures are as follows:

[0072] Figure 5 (b) shows a radial gradient micropore / microchannel network: its internal microstructures are distributed in a ring array. In order to guide the gas to generate differentiated diffusion rates in the radial direction, the pore size or channel distribution density of this network is not uniform, but gradually increases from the central inlet region to the outer edge region (exhibiting a spatial gradient from small to large).

[0073] Figure 5 (c) shows a spiral diffusion network: its channel structure originates from the central air inlet and extends outward in a continuous spiral pattern, forcing the gas to follow the spiral trajectory for transmission, thereby forming a rotating and extended gas flow field distribution pattern in the matrix.

[0074] Figure 5 Figure (d) shows a striped anisotropic diffusion network, which consists of an array of parallel straight channels. This specific orientation geometry results in less resistance to the gas in the main direction parallel to the channels, while the resistance is greater in the transverse diffusion direction perpendicular to the channels. This significant physical anisotropy is used to achieve directional guidance and selective retention of the airflow.

[0075] Figure 5 (e) shows a fractal diffusion network: its connecting channels exhibit irregular branching growth characteristics similar to tree branches or multi-level veins in nature from the center outwards, allowing gas to be distributed multiple times in a complex multi-level branching network.

[0076] By changing the pore density distribution, main channel direction, local physical resistance, and relative position of the release pores in the above structure, the exposure history and concentration response of different sensor units below in the time and space dimensions can be actively controlled.

[0077] Example 6: Micro-pre-separation-release pathway

[0078] like Figure 6 As shown, in a further embodiment, a glass three-dimensional gas transport path encoding chip with micro pre-separation and release timing control functions is provided. In the overall assembly structure, the device has a sample inlet at the front end of the gas path and is mainly composed of a transparent glass or quartz substrate 2 located above and a one-dimensional linear gas sensing array 4 disposed below it, stacked in an airtight manner.

[0079] Inside the transparent glass or quartz substrate 2, along the longitudinal main axis of the gas flow, the entire three-dimensional transport path is continuously divided into three core functional blocks: the inlet focusing area, the retention or interaction area, and the branch release area.

[0080] During operation, the complex gas sample to be tested is first injected through a single inlet on the left. The gas first enters the "inlet focusing zone," where the gas flow converges and the flow field is shaped within a funnel-shaped, narrowing channel, establishing a uniform initial injection state. Subsequently, the gas enters the central and longest "retention or interaction zone." The main channel in this region exhibits multiple consecutive bends, with alternating local microcavities and expansion cavities containing arrayed microstructures (such as micropores or micropillars) at the bend nodes. This complex geometry, characterized by high resistance and long distances, forces the originally mixed gas molecules to undergo differentiated physical diffusion and retention on the inner walls during transport, thereby achieving preliminary physical pre-separation and transport delay for different components. Finally, the deeply modulated gas flows to the "branch release zone" on the right, where the main gas path is diverted and guided, exiting through the first, second, third, fourth, and fifth outlets located at the end of the network.

[0081] Due to the profound modulation effect generated within the retention or interaction zones, and the distribution differences in each branch channel, the gases ultimately arriving at these five outlets are endowed with a significant sequential gradient on the time axis. As vividly illustrated by the interlayer dashed line and timing text between the transparent glass or quartz substrate 2 and the underlying gas sensing array 4 in the figure: these gases do not arrive synchronously, but rather follow a strict relay sequence, acting precisely on the corresponding first, second, third, fourth, and fifth sensors in the array below in a time rhythm of "release first," "release later," "release after that," "release even later," and finally "release last."

[0082] Example 7: Assembly and Sealing

[0083] In a preferred embodiment, the glass three-dimensional gas transport path encoding chip does not have directly provided force-bearing screw holes, but is fixed by an external clamping frame, clamp, elastic clamping element, or peripheral threaded fastener. The threaded fastener is preferably set on the clamping frame or support on the outer periphery of the transparent substrate to avoid forming local point loads on the glass chip.

[0084] A sealing gasket with multiple corresponding orifices is placed between the transparent glass or quartz substrate and the gas sensing array. The sealing gasket can be made of FKM, PTFE, ePTFE, silicone, or other materials resistant to volatile organic compounds. An independent sealing area can be provided around each release port to reduce lateral gas leakage between paths. The compression of the sealing gasket can be controlled by a limiting post, an elastic washer, or a buffer pad.

[0085] Example 8: Detection and Analysis Methods

[0086] During detection, the volatile organic compound (VOC) sample is introduced into the inlet of the glass three-dimensional gas transport path encoding chip, allowing it to be transported in parallel through at least two three-dimensional gas transport paths. Samples modulated by different paths are released to corresponding sensing areas through multiple release ports. Time response signals from multiple sensing channels are simultaneously acquired. Peak value, response area, peak time, rise time, half-maximum width, recovery time, inter-path response ratio, inter-path correlation, and spatial distribution characteristics are extracted from the response signals. A spatiotemporal response encoding map is constructed based on these characteristics. Based on the map, VOC identification, concentration range determination, or sample category classification is performed.

[0087] The method is applicable to alcohols, aldehydes, ketones, acids, esters, aromatic compounds, sulfur-containing compounds, nitrogen-containing compounds and their mixtures, and can also be used for grains, food, tea, tobacco, traditional Chinese medicine, ambient air, fermentation samples, moldy samples and industrial process samples.

[0088] Industrial applicability

[0089] The glass three-dimensional gas transport path encoding chip and volatile organic compound detection method provided by the present invention have the advantages of stable structure, high path encoding dimension, simplified test process, and can be coupled with a single sensitive material or a sensor array of homologous sensitive materials.

[0090] This invention can be widely applied in fields such as volatile organic compound identification, complex odor classification, food safety, grain storage and transportation, environmental monitoring, fermentation process monitoring, and mold sample screening.

Claims

1. A glass three-dimensional gas transport path encoding chip, characterized by, include: A transparent glass or quartz substrate; at least one gas inlet disposed on the transparent glass or quartz substrate; at least two three-dimensional gas transport paths formed by ultrafast laser writing inside the transparent glass or quartz substrate; a plurality of gas release ports communicating with the at least two three-dimensional gas transport paths; and a gas sensing array arranged corresponding to the plurality of gas release ports; a sealing gasket is disposed between the transparent glass or quartz substrate and the gas sensing array, the sealing gasket having through holes corresponding to the plurality of gas release ports; wherein, the at least two three-dimensional gas transport paths have different path lengths, channel cross-sectional areas, bending structures, expansion cavities, local contraction sections, depth levels, vertical connection structures, three-dimensional folding structures, branching structures, release positions, or inner surface states, so that volatile organic compounds entering the gas inlet generate different diffusion, residence, delay, release, or arrival histories in different three-dimensional gas transport paths, and the gas sensing array reads and forms a spatiotemporal response coding spectrum.

2. The glass three-dimensional gas transport path encoding chip according to claim 1, characterized in that, The transparent glass or quartz substrate is borosilicate glass, quartz glass, fused silica, or transparent ceramic; the ultrafast laser is a femtosecond laser, picosecond laser, or a combination thereof; the at least two three-dimensional gas transport paths are formed sequentially by laser writing, etching, cleaning, annealing, and surface treatment processes; the at least two three-dimensional gas transport paths include straight paths, long straight paths, serpentine paths, spiral paths, labyrinth paths, expansion-contraction paths, three-dimensional folding paths, branching paths, and microcavity array paths; at least one of the at least two three-dimensional gas transport paths includes a local expansion cavity and a local contraction section, used to control the residence time, peak width, release rate, or recovery process of volatile organic compounds in the path.

3. The glass three-dimensional gas transport path encoding chip according to claim 1, characterized in that, The at least two three-dimensional gas transport paths are distributed at different depth levels inside the transparent glass or quartz matrix and are connected by vertical connecting channels. Their three-dimensional gas transport paths intersect in spatial projection but are not connected to each other.

4. The glass three-dimensional gas transport path encoding chip according to claim 1, characterized in that, The multiple gas release ports are arranged in a one-dimensional linear array, a two-dimensional matrix array, a ring array, a radial array, or an irregular array, and correspond to multiple sensing sites in the gas sensing array; the at least two three-dimensional gas transport paths are connected and work in parallel during a single sample injection process, and can form multi-path spatiotemporal response coding without relying on the time-sequential opening or closing of multiple gas release ports.

5. The glass three-dimensional gas transport path encoding chip according to claim 1, characterized in that, The gas sensing array is a resistive, impedance, capacitive, current-based, optical, mass-based, or electrochemical sensing array; the sensing units in the gas sensing array use the same or homologous sensitive materials; the sensitive materials include carbon materials, graphene, reduced graphene oxide, conductive polymers, metal oxides, metal-organic framework materials, coordination polymers, and composite porous materials.

6. The glass three-dimensional gas transport path encoding chip according to claim 1, characterized in that, The transparent glass or quartz substrate has a gas diffusion metasurface formed by ultrafast laser writing inside or near the surface. The gas diffusion metasurface includes micropore arrays, microcavity arrays, microgroove arrays, spiral channels, radial gradient channels, striped anisotropic channels, and fractal diffusion networks.

7. The glass three-dimensional gas transport path encoding chip according to claim 1, characterized in that, At least one of the at least two three-dimensional gas transport paths includes an inlet focusing region, a retention or interaction region, and a branch release region.

8. The glass three-dimensional gas transport path encoding chip according to claim 1, characterized in that, The transparent glass or quartz substrate is pressed and sealed to the sealing gasket and the gas sensing array by an external clamping frame, clamp, elastic clamping element or external threaded fastener, and the external threaded fastener does not pass through the stress area of ​​the transparent glass or quartz substrate.

9. A volatile organic compound detection system based on the glass three-dimensional gas transport path encoding chip of claim 1, characterized in that, The system includes a VOC sample introduction module, a laser-written glass three-dimensional gas transport path encoding chip module, a signal acquisition module, a data processing and recognition module, and an output result module. The VOC sample introduction module is used to introduce sample gas into the gas inlet. The laser-written glass three-dimensional gas transport path encoding chip module has its gas input end connected to the VOC sample introduction module. This module is composed of a transparent glass or quartz substrate, a sealing gasket, and a gas sensor array assembled in a gas-tight manner. It receives sample gas from the VOC sample introduction module, allowing volatile organic compounds to be transported in parallel through multiple three-dimensional gas transport paths within the transparent glass or quartz substrate and undergoing physical transport modulation. Subsequently, the gas is released through the sealing gasket to the corresponding gas sensor array, converting the volatile organic compound sample into a volatile organic compound sample. Multi-channel sensing response; the signal acquisition module, electrically connected to the gas sensing array in the laser-written glass three-dimensional gas transport path encoding chip module, is used to synchronously receive and acquire multi-channel time response signals of resistance, impedance, current, voltage, or capacitance output from multiple sensing sites; the data processing and recognition module, communicatively connected to the signal acquisition module, is used to extract peak value, response area, peak time, rise time, half-peak width, recovery time, inter-path response ratio, inter-path correlation, or spatial distribution characteristics, and construct a spatiotemporal response encoding map based on the characteristics for dimensionality reduction, classification, or regression analysis and recognition; the output result module, connected to the data processing and recognition module, is used to receive the recognition results and visualize the types, concentration ranges, or sample categories of volatile organic compounds.

10. A method for detecting volatile organic compounds based on a glass three-dimensional gas transport path encoding chip, characterized in that, Includes the following steps: A volatile organic compound (VOC) sample is introduced into a gas inlet on a transparent glass or quartz substrate, allowing the VOC sample to be transported in parallel along at least two three-dimensional gas transport paths. The VOC, modulated by the three-dimensional gas transport paths, is released to corresponding gas sensing arrays through multiple gas release ports. Multi-channel time response signals from the gas sensing arrays are simultaneously acquired. A spatiotemporal response coding map of the VOC is constructed based on the multi-channel time response signals, and the VOC or samples containing VOC are identified based on the spatiotemporal response coding map. The spatiotemporal response coding map includes path dimension, release location dimension, sensing channel dimension, and time dimension; the volatile organic compounds include alcohols, aldehydes, ketones, acids, esters, aromatic compounds, sulfur-containing compounds, nitrogen-containing compounds, or mixtures thereof; the samples containing volatile organic compounds include grains, food, tea, tobacco, traditional Chinese medicine, ambient air, fermented samples, and moldy samples; the identification includes principal component analysis, linear discriminant analysis, support vector machine, random forest, convolutional neural network, partial least squares regression, cluster analysis, or combinations thereof.

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