Array pressure sensor for detecting subcutaneous mass

Abstract

The array pressure sensor comprises an upper P I layer, an upper conductive layer, an upper functional layer, an isolating layer, a lower functional layer, a lower conductive layer and a lower P I layer which are sequentially stacked from top to bottom, each of the upper conductive layer and the lower conductive layer is composed of a plurality of conductive points which are arranged in a longitudinal and transverse array manner; each of the upper functional layer and the lower functional layer is composed of a plurality of varistor ink points which are arranged in a longitudinal and transverse array manner; the varistor ink points of the functional layers are in one-to-one correspondence with the conductive points of the conductive layer; a plurality of avoiding holes penetrating through the upper side and the lower side of the isolation layer are formed in the isolation layer in a longitudinal and transverse array mode, and the avoiding holes correspond to the piezoresistor ink points one to one; and the upper and lower corresponding conductive points and the piezoresistor ink points form a data acquisition point. The array pressure sensor has the advantages that the array pressure sensor is in flexible contact with skin during use, pressure is calibrated by resistors according to resistance change in a conductive loop caused by pressure change, and measurement is convenient and fast. The flexible arrangement of the sensor reduces the discomfort of the patient and improves the measurement precision.

Description

An array pressure sensor for detecting subcutaneous masses Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to an array pressure sensor for detecting subcutaneous masses. Background Technology

[0002] Long-term insulin injections in diabetic patients can easily lead to the formation of subcutaneous lumps at the injection site. These lumps not only affect drug absorption but can also cause complications such as skin infections. Currently, doctors typically assess the presence and development of subcutaneous lumps through palpation, but this method relies on the doctor's experience and cannot quantify the characteristics of the lumps. Patients also find it difficult to assess the formation and development of lumps at home. Therefore, developing a pressure-sensing system capable of automatically detecting and quantifying subcutaneous lumps has significant clinical implications.

[0003] Most existing pressure sensing systems employ uniformly distributed sensor arrays. While these can cover a large detection area, in practical applications, the location and size of subcutaneous lumps are uncertain. A uniformly distributed sensor array leads to the collection of a large amount of invalid data, increasing data processing workload and system cost. Furthermore, existing systems typically provide sensors with only a single resolution, which cannot adapt to the detection needs of subcutaneous lumps of varying sizes and hardness. Summary of the Invention

[0004] The purpose of this invention is to provide a pressure sensor for detecting subcutaneous lumps, thereby solving the aforementioned problems in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] An array pressure sensor for detecting subcutaneous masses includes, from top to bottom, an upper PI layer, an upper conductive layer, an upper functional layer, an isolation layer, a lower functional layer, a lower conductive layer, and a lower PI layer. The upper and lower conductive layers are each composed of multiple conductive points arranged in a horizontal and vertical array, with each conductive point in the upper and lower conductive layers corresponding one-to-one. The upper and lower functional layers are each composed of multiple piezoresistive ink dots arranged in a horizontal and vertical array, with each piezoresistive ink dot in the upper and lower functional layers corresponding one-to-one with the conductive points in the upper and lower conductive layers, respectively. The isolation layer has multiple clearance holes arranged in a horizontal and vertical array penetrating its upper and lower sides, with each clearance hole corresponding one-to-one with the piezoresistive ink dots in the upper and lower functional layers. The corresponding conductive points in the upper conductive layer, the upper functional layer, the lower functional layer, and the lower conductive layer together constitute a data acquisition point.

[0007] Preferably, each conductive point in each vertical column of the upper conductive layer is sequentially connected to the corresponding gold finger in that column, and each conductive point in each horizontal row of the lower conductive layer is sequentially connected to the corresponding gold finger in that row. The gold finger is plugged into and detached from the FPC connector, the FPC connector is connected to the MCU microcontroller, and the MCU microcontroller is connected to the data processing device.

[0008] Preferably, the diameter of the varistor ink dots is larger than the diameter of the conductive dots.

[0009] Preferably, the diameter of the clearance hole is smaller than the diameter of the varistor ink dot.

[0010] Preferably, the upper PI layer and the lower PI layer are polyimide films.

[0011] Preferably, the conductive point is a copper point.

[0012] Preferably, the isolation layer is OCA double-sided adhesive.

[0013] Preferably, the array pressure sensor includes three sizes.

[0014] Minimum size: The diameter of the varistor ink dots is 1mm, the spacing between two adjacent varistor ink dots is 2mm, and 100 data acquisition points are arrayed within a 20mm*20mm range;

[0015] Medium size: The diameter of the varistor ink dots is 2mm, the spacing between two adjacent varistor ink dots is 3mm, and 100 data acquisition points are arrayed within a 30mm*30mm range;

[0016] Maximum size: The diameter of the varistor ink dots is 4mm, the spacing between two adjacent varistor ink dots is 5mm, and 100 data acquisition points are arrayed within a range of 50mm*50mm.

[0017] Preferably, the array pressure sensor further includes a dispensing layer stacked above the upper PI layer; the dispensing layer consists of multiple adhesive dots arranged in a longitudinal and transverse array, and each adhesive dot corresponds one-to-one with a data acquisition point.

[0018] Preferably, the diameter of the adhesive dots is smaller than the diameter of the ink dots on the varistor.

[0019] The beneficial effects of this invention are: 1. The array pressure sensor makes flexible contact with the skin during use. Pressure is calibrated using resistance based on the change in resistance in the conductive circuit caused by pressure changes, making measurement convenient and quick. The flexible sensor design reduces patient discomfort and improves measurement accuracy. 2. The adhesive layer on the sensor increases the effective force-bearing area, improving accuracy. 3. Three different sizes of sensor arrays are designed to adapt to the detection needs of subcutaneous masses of different sizes and hardness, providing real-time visualization of pressure distribution to help doctors and patients assess the development of subcutaneous masses. 4. The sensor uses an island-style distribution, rather than a completely filled distribution, reducing unnecessary sampling points in healthy areas, lowering data processing volume and cost. Attached Figure Description

[0020] Figure 1 is a structural diagram of the array pressure sensor in an embodiment of this utility model;

[0021] Figure 2 is a schematic diagram of the arrangement of the array pressure sensor in an embodiment of this utility model.

[0022] In the diagram: 1. Adhesive layer; 2. Upper PI layer; 3. Upper conductive layer; 4. Upper functional layer; 5. Isolation layer; 6. Lower functional layer; 7. Lower conductive layer; 8. Lower PI layer; 9. Array pressure sensor; 10. Skin; 11. Mass. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0024] As shown in Figure 1, this embodiment provides an array pressure sensor for detecting subcutaneous masses, comprising, from top to bottom, an upper PI layer 2, an upper conductive layer 3, an upper functional layer 4, an isolation layer 5, a lower functional layer 6, a lower conductive layer 7, and a lower PI layer 8. The upper conductive layer 3 and the lower conductive layer 7 are each composed of multiple conductive points arranged in a horizontal and vertical array, with the conductive points of the upper conductive layer 3 and the lower conductive layer corresponding one-to-one. The upper functional layer 4 and the lower functional layer 6 are each composed of multiple pressure-sensitive resistor ink dots arranged in a horizontal and vertical array. The varistor ink dots of the upper functional layer 4 and the lower functional layer 6 correspond one-to-one with the conductive dots of the upper conductive layer 3 and the lower conductive layer 7, respectively. The isolation layer 5 is provided with a plurality of clearance holes arranged in a longitudinal and transverse array, which correspond one-to-one with the varistor ink dots of the upper functional layer 4 and the lower functional layer 6. The conductive dots of the upper conductive layer 3, the varistor ink dots of the upper functional layer 4, the varistor ink dots of the lower functional layer 6, and the conductive dots of the lower conductive layer 7 together constitute a data acquisition point.

[0025] Upper PI layer 2 and lower PI layer 8: The material used is polyimide (PI) film. PI film is wear-resistant, corrosion-resistant, and flexible. It is often used as a flexible substrate for flexible electronics and can withstand the sintering temperature of 200 degrees Celsius for functional layer inks.

[0026] Upper conductive layer 3 and lower conductive layer 7: These are made of copper and consist of a 10x10 array of circular dots. In the upper conductive layer 3, each column of conductive dots is sequentially connected to the corresponding gold finger in that column. Similarly, in the lower conductive layer 7, each row of conductive dots is sequentially connected to the corresponding gold finger in that row. The upper and lower gold fingers are parallel but do not overlap. PI reinforcement is added to the back of the gold fingers to facilitate the insertion and removal of the FPC connector.

[0027] Upper functional layer 4 and lower functional layer 6: The material used is varistor ink. The ink is printed onto 10*10 conductive dots on the upper and lower conductive layers 7 using screen printing technology. The diameter of each ink dot is slightly larger than the diameter of the conductive dot to ensure that the ink completely covers the conductive dot, preventing direct contact between the upper and lower conductive layers 7 and the formation of a short circuit under pressure. The position of each ink dot corresponds vertically to the position of each conductive dot.

[0028] The isolation layer 5 is made of OCA adhesive, and a double-sided adhesive with a thickness of 100 micrometers is laser-cut to correspond to this thickness. During encapsulation, if the edge of the clearance hole in the isolation layer 5 falls on the PI substrate outside the ink dots, the insufficient thickness of the isolation layer 5 may cause the upper and lower functional layers 6 to contact in the initial state, resulting in zero-point drift. This is due to the lack of a fixed cavity between the upper and lower functional layers 6. Therefore, the diameter of the clearance hole in the isolation layer 5 should be slightly smaller than the diameter of the ink dots in the functional layers to ensure that the edge of the clearance hole in the isolation layer 5 is within the edge of the ink dots in the functional layers during encapsulation. The upper and lower functional layers 6 are initially separated by a fixed distance of 100 micrometers.

[0029] Because each sensing point (data acquisition point) is very small, while the object applying pressure (e.g., the size of a human finger) is relatively large, most of the applied pressure is distributed across the area outside the sensing point (such as the blank area between sensing points), making it difficult to press directly onto the sensing point. Furthermore, since each sensing point is initially isolated vertically, a cavity is created between the upper and lower functional layers 6 by an isolation layer 5. When pressure is applied, the upper and lower functional layers 6 need to contact to form a sensor. Therefore, the sensor surface needs to be pressed downwards to generate a change in resistance and display pressure sensing. However, the size of the object applying pressure makes it difficult to press the sensing point surface inwards. Therefore, an adhesive layer 1 is applied to the upper PI layer 2.

[0030] Adhesive layer 1: Adhesive is applied to each sensing point, creating a protrusion on the outer side of the sensing point. When a pressurized object contacts the sensor array, it first comes into contact with the plane of adhesive layer 1, allowing adhesive layer 1 to better transmit force to the functional layer below under pressure. Each adhesive application position corresponds to a position on the functional layer below, forming a 10*10 array. The size of each adhesive application is slightly smaller than the diameter of the ink dot on the functional layer, ensuring that it is not restricted by the clearance holes on the isolation layer 5 when subjected to downward force.

[0031] In this embodiment, each of the following layers has a 10*10 array of dots: dispensing layer 1, upper conductive layer 3, upper functional layer 4, isolation layer 5, lower functional layer 6, and lower conductive layer 7. The positions of the dots in each layer are the same in the Z-axis direction.

[0032] In this embodiment, in order to accommodate subcutaneous masses 11 of different sizes and hardness, three different sizes of array pressure sensors 9 were designed to meet the needs of pressure objects of different sizes. The different sizes of the design ensure that each pressure object has a sufficient number of sensing points.

[0033] (1) Minimum size: The diameter of the functional layer circle is 1mm, the spacing between each circle point is 2mm, and 100 data acquisition points are distributed in an array within a range of 20mm*20mm.

[0034] (2) Medium size: The diameter of the functional layer circle is 2mm, the spacing between each circle point is 3mm, and 100 data acquisition points are arrayed within a range of 30mm*30mm.

[0035] (3) Maximum size: The diameter of the functional layer circle is 4mm, the spacing between each circle point is 5mm, and 100 data acquisition points are distributed in an array within a range of 50mm*50mm.

[0036] In this embodiment, for each sensing point, the conductive circuit is as follows: upper conductive layer 3 (gold finger) --- upper functional layer 4 (circle) --- upper functional layer 4 --- lower functional layer 6 --- lower conductive layer 7 (circle) --- lower conductive layer 7 (gold finger). Since the conductive layer material is copper, and the sheet resistance of the functional layer ink is between 20kΩ and 2000kΩ (adjustable), the resistance of the conductive layer is very low compared to the resistance of the functional layer and is essentially negligible in the circuit. The main resistance variation in the circuit originates from the resistance variation of the functional layer.

[0037] Working principle of array pressure sensor 9: When array pressure sensor 9 is pressurized, the adhesive layer 1 is pressed downwards, causing the PI layer, upper conductive layer 3, and upper functional layer 4 to contact the lower functional layer 6, forming a conductive circuit after the upper and lower functional layers 6 come into contact. Due to the piezoresistive effect of the functional layer ink (the greater the pressure, the lower the resistance), the resistance in the conductive circuit decreases as the pressure increases, and the pressure can be calibrated by the resistance value.

[0038] Data acquisition method for array pressure sensor 9: Data acquisition is performed using an array scanning method. First, the first horizontal gold finger is connected to the positive terminal, and the ten vertical gold fingers are connected to the negative terminals in sequence. The resistance value of each sensing point in the first row is measured. This process is repeated to measure the resistance value of the 10*10 array.

[0039] As shown in Figure 2, the array pressure sensor 9 is installed in an island-style distribution on the skin 10 with subcutaneous masses 11, which saves on sensor distribution and reduces the difficulty of data acquisition.

[0040] Each pressure array sensor's gold fingers are led out via an FPC connector and uniformly connected to an external MCU microcontroller. The MCU is an STM32F303VCT6, using four CD4067 multiplexers. The MCU connects to the data processing device via a Bluetooth module. Bluetooth communication uses a Daxia Longque BT24-T module. The sensor resistance values ​​are sequentially acquired using a horizontal and vertical scanning method. The acquired resistance signals are connected to the MCU microcontroller via a port. The MCU microcontroller processes the signals and then wirelessly transmits the processed signals to the data processing device (such as a mobile phone or computer) via the Bluetooth module.

[0041] The data processing equipment includes a data processing terminal that uses a visualization platform programmed with LabVIEW to display pressure distribution in real time, helping doctors and patients identify the growth of the subcutaneous mass 11. The terminal has a built-in algorithm model that analyzes the collected resistance data by combining medical knowledge about the correlation between thrombosis and human physiological changes. By comparing the resistance value range under normal physiological conditions with the currently collected data, the development cycle of the subcutaneous mass 11 can be determined. The terminal also has data storage capabilities, saving historical test data to allow users to view health data trends and provide data support for medical research.

[0042] By adopting the above-disclosed technical solution of this utility model, the following beneficial effects are obtained:

[0043] This invention provides an array pressure sensor for detecting subcutaneous masses. The array pressure sensor flexibly contacts the skin during use, and pressure is calibrated using resistance changes in the conductive circuit caused by pressure variations, making measurement convenient and quick. The flexible sensor design reduces patient discomfort and improves measurement accuracy. The adhesive layer on the sensor increases the effective force-bearing area, further enhancing accuracy. Three different sensor array sizes are designed to accommodate the detection needs of subcutaneous masses of varying sizes and hardness, providing real-time visualization of pressure distribution to help doctors and patients assess the development of subcutaneous masses. The sensor employs an island-style distribution, rather than a completely filled distribution, reducing unnecessary sampling points in healthy areas, thus lowering data processing volume and costs.

[0044] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An array pressure sensor for detecting subcutaneous masses, characterized in that: The system comprises, from top to bottom, an upper PI layer, an upper conductive layer, an upper functional layer, an isolation layer, a lower functional layer, a lower conductive layer, and a lower PI layer. Both the upper and lower conductive layers consist of multiple conductive points arranged in a horizontal and vertical array, with each conductive point in the upper and lower conductive layers corresponding one-to-one. Both the upper and lower functional layers consist of multiple varistor ink dots arranged in a horizontal and vertical array, with each varistor ink dot corresponding one-to-one with the conductive points in the upper and lower conductive layers, respectively. The isolation layer has multiple clearance holes arranged in a horizontal and vertical array, penetrating its upper and lower sides, with each clearance hole corresponding one-to-one with the varistor ink dots in the upper and lower functional layers. The corresponding conductive points of the upper conductive layer, the upper functional layer, the lower functional layer, and the lower conductive layer together constitute a data acquisition point.

2. The array pressure sensor for detecting subcutaneous masses according to claim 1, characterized in that: Each conductive point in each vertical column of the upper conductive layer is sequentially connected to the corresponding gold finger in that column. Each conductive point in each horizontal row of the lower conductive layer is sequentially connected to the corresponding gold finger in that row. The gold finger is plugged into and detached from the FPC connector. The FPC connector is connected to the MCU microcontroller. The MCU microcontroller is connected to the data processing device.

3. The array pressure sensor for detecting subcutaneous masses according to claim 1, characterized in that: The diameter of the ink dots on the varistor is larger than the diameter of the conductive dots.

4. The array pressure sensor for detecting subcutaneous masses according to claim 1, characterized in that: The diameter of the clearance hole is smaller than the diameter of the ink dot on the varistor.

5. The array pressure sensor for detecting subcutaneous masses according to claim 1, characterized in that: The upper PI layer and the lower PI layer are polyimide films.

6. The array pressure sensor for detecting subcutaneous masses according to claim 1, characterized in that: The conductive point is a metallic copper point.

7. The array pressure sensor for detecting subcutaneous masses according to claim 1, characterized in that: The isolation layer is OCA double-sided adhesive.

8. The array pressure sensor for detecting subcutaneous masses according to claim 1, characterized in that: The array pressure sensor includes three sizes: the smallest size, where the diameter of the piezoresistive ink dots is 1mm and the spacing between two adjacent piezoresistive ink dots is 2mm, with 100 data acquisition points distributed in an array within a 20mm*20mm range; the medium size, where the diameter of the piezoresistive ink dots is 2mm and the spacing between two adjacent piezoresistive ink dots is 3mm, with 100 data acquisition points distributed in an array within a 30mm*30mm range; and the largest size, where the diameter of the piezoresistive ink dots is 4mm and the spacing between two adjacent piezoresistive ink dots is 5mm, with 100 data acquisition points distributed in an array within a 50mm*50mm range.

9. The array pressure sensor for detecting subcutaneous masses according to any one of claims 1 to 8, characterized in that: The array pressure sensor also includes a dispensing layer stacked above the upper PI layer; the dispensing layer consists of multiple adhesive dots arranged in a longitudinal and transverse array, and each adhesive dot corresponds one-to-one with a data acquisition point.

10. The array pressure sensor for detecting subcutaneous masses according to claim 9, characterized in that: The diameter of the adhesive dots is smaller than the diameter of the ink dots on the varistor.

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