Encapsulation structure of intracranial pressure monitoring pressure sensor probe

Abstract

The utility model provides an intracranial pressure monitoring pressure sensor probe packaging structure, which belongs to the technical field of sensors, and comprises a hose, a titanium base and a chip, the chip is fixed on the titanium base, the titanium base is attached in the hose, one end of the hose is coated with biocompatible glue, the hose is filled with soft glue, the other end of the hose is sealed, and the chip is fixed on the titanium base. A lead on the chip penetrates out of the other end of the hose; the flexible pipe with the fixed and controllable diameter is adopted, and the flexible glue for transmitting pressure is limited in the flexible pipe with the fixed diameter, so that the flexible glue on the upper surface of the chip is smooth in surface and uniform, accurate and controllable in thickness, and compared with an existing open type glue filling mode, the flexible glue is accurate and controllable in thickness, and the measurement accuracy of the intracranial pressure sensor can be guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to the packaging structure of a pressure sensor probe for intracranial pressure monitoring. Background Technology

[0002] Intracranial pressure monitoring (IPP) measures the pressure of the cranial contents against the cranial walls. It requires placing an IPP probe inside the skull, typically in the frontal or occipital region. The sensor transmits the IPP waveform to a workstation, providing a complete understanding of IPP changes. Analyzing these changes helps determine the severity of the injury and the extent of cerebral edema, thus informing treatment and prognosis. Current IPP monitoring technology, considering the operating environment, generally uses small-diameter pressure sensors, typically piezoresistive or fiber optic pressure sensors, assembled with a titanium base to connect to the main unit.

[0003] For example, the Chinese utility model patent "Integrated Intracranial Pressure Sensor Strip" with announcement number CN211121765U discloses a sensor strip including a catheter and a pressure sensing mechanism. The catheter is tubular with a closed, cone-shaped front end and a hole on the surface of the tube at the front end. The pressure sensing mechanism is set inside the catheter and fixed tightly. The pressure sensing mechanism is connected to a wire, which passes through the inner cavity of the catheter and exits from the opening at the rear end of the catheter. The chip is fixed on the base and is connected to the wire and communicates with the outside through the hole on the surface of the catheter to monitor pressure. For example, Chinese invention patent application CN113080922A, entitled "Packaging Structure and Method of Catheter-type Intracranial Pressure Measurement Probe", discloses a packaging structure for a catheter-type intracranial pressure measurement probe, including a flexible circuit board and a sealed medical catheter. The flexible circuit board includes multiple pad areas, at least one chip placement area, and at least one pair of overlapping adhesive areas. The flexible circuit board is bent into a ring shape and fitted into the lumen of the medical catheter. At least one chip placement area is used to place a pressure sensing chip. The medical catheter has a slot, through which the pressure sensing chip on the flexible circuit board protrudes from the medical catheter. The flexible circuit board is sealed at the slot with biocompatible adhesive.

[0004] The common feature of the two patent applications is that they require opening a hole on the surface of the pressure sensor to sense intracranial pressure, and using an open-type glue-filling method to cover the hole with glue. To ensure biocompatibility, a sufficiently thick layer of glue needs to be applied to the hole, with an actual thickness of about 500 micrometers. In order to reduce the thickness deviation during multiple glue application processes, the consistency of each application must be ensured. This places extremely high demands on the control precision of the glue dispensing machine. Once the control precision of the glue dispensing machine deviates, it will cause changes in the glue coverage thickness. Changes in glue coverage thickness will directly cause changes in the pressure transmission value, resulting in poor sensor consistency and making the calibration and testing process more complicated. Excessive glue thickness will also affect the performance of the sensor. All of these factors will lead to a decrease in the measurement accuracy of the intracranial pressure sensor. Utility Model Content

[0005] The technical problem to be solved by this invention is how to improve the measurement accuracy of intracranial pressure sensors.

[0006] This utility model solves the above-mentioned technical problems through the following technical solution: an intracranial pressure monitoring pressure sensor probe packaging structure, including a tubing, a titanium base, and a chip. The chip is fixed on the titanium base, the titanium base is attached to the inside of the tubing, one end of the tubing is coated with biocompatible adhesive, the inside of the tubing is filled with soft glue and the other end of the tubing is sealed, and the leads on the chip pass through the other end of the tubing.

[0007] This invention uses a flexible tube with a fixed and controllable diameter to confine the pressure-transmitting soft adhesive inside the tube, resulting in a smooth, uniform, and precisely controllable surface of the soft adhesive on the chip. Compared to existing open-type adhesive filling methods, the thickness of the soft adhesive in this invention is precisely controllable, ensuring the measurement accuracy of the intracranial pressure sensor.

[0008] Preferably, the cross-section of the hose is circular, and the cross-section of the titanium base is a semi-circle with the same curvature as the hose.

[0009] Preferably, the lower surface of the titanium base is attached to the inner wall of the flexible tube, and the chip is fixed to the upper surface of the titanium base.

[0010] Preferably, the lower surface of the titanium base is bonded to the inner wall of the flexible tube by die bonder adhesive, and the chip is bonded to the upper surface of the titanium base by die bonder adhesive.

[0011] Preferably, the thickness of the die bond adhesive is 100μm-500μm.

[0012] Preferably, the hoses at both ends of the titanium base at the installation position are reserved with a set length.

[0013] Preferably, the end of the flexible tube at one end of the titanium base is coated with biocompatible adhesive, and the end of the flexible tube at the other end is reserved for a certain length.

[0014] Preferably, the end of the tubing coated with biocompatible adhesive has a smooth structure.

[0015] Preferably, the soft rubber is a medium for transmitting pressure.

[0016] The advantages provided by this utility model are:

[0017] (1) This utility model uses a flexible tube with a fixed and controllable diameter to confine the soft glue that transmits pressure inside the flexible tube with a fixed diameter, so that the surface of the soft glue on the chip is flat, the thickness is uniform and the thickness is precisely controllable. Compared with the existing open glue filling method, the thickness of the soft glue in this utility model is precisely controllable, which can ensure the measurement accuracy of the intracranial pressure sensor.

[0018] (2) The titanium base of this utility model is located inside a closed hose, so there is no need to worry about the base falling off during use, ensuring the safety of the intracranial pressure sensor. Furthermore, the titanium base does not need to be finely machined into a ring structure for the bayonet pressure sensor harness, which greatly reduces the technical difficulty and cost of sensor processing. Attached Figure Description

[0019] Figure 1 A schematic diagram of the packaging structure of the intracranial pressure monitoring pressure sensor probe provided in this embodiment of the utility model;

[0020] Figure 2 (a) and (b) are schematic diagrams of the existing sensor probe packaging structure before and after adopting the open-type glue filling method, respectively;

[0021] Figure 3 (a) and (b) are schematic diagrams of the intracranial pressure monitoring pressure sensor probe packaging structure provided in this embodiment of the present invention, showing the front and back of the process of filling the tube with glue.

[0022] In the diagram: 10 flexible tube, 20 titanium base, 30 die bond adhesive, 40 chip, 41 lead wire, 50 biocompatible adhesive, 60 soft adhesive. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model are described clearly and completely below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0024] like Figure 1As shown, this embodiment provides a packaging structure for an intracranial pressure monitoring pressure sensor probe, including a flexible tube 10, a titanium base 20, and a chip 40. The cross-section of the flexible tube 10 is generally circular, facilitating insertion and removal into the cranium. The flexible tube 10 is made of nylon, while the titanium base 20 is made of titanium alloy. The titanium base 20 does not require fine machining to create a ring structure for fixing the wire harness; it only requires a titanium metal wire with a semi-circular cross-section. The titanium alloy base is used to support the chip, and the metal base allows for accurate determination of the sensor's placement under X-ray and CT scans. The cross-section of the titanium base 20 is a semi-circle with the same curvature as the cross-section of the flexible tube 10, ensuring that the lower surface of the titanium base 20 fits precisely against the inner wall of the flexible tube 10. The two can be fixed by applying adhesive to the mounting surface between the titanium base 20 and the flexible tube 10, or by bonding a DAF film to the mounting surface between the titanium base 20 and the flexible tube 10.

[0025] The upper surface of the titanium base 20 is coated with die bond adhesive 30. The chip 40 is bonded to the upper surface of the titanium base 20 by the die bond adhesive 30. The thickness of the die bond adhesive 30 is generally less than 1 mm, usually set to 100 μm-500 μm. The die bond adhesive 30 can be a thin film material or a polymer material. The thin film material can be a DAF film, which can ensure micron-level precision. The polymer material can be epoxy resin or silicone, etc. The die bond adhesive 30 fixes the chip 40 to the titanium base 20, which can prevent the chip 40 from moving relative to the titanium base 20. One end of the flexible tube 10 is coated with biocompatible adhesive 50 to form a smooth probe head structure. In order to facilitate the placement of the sensor through the brain tissue during the operation, an adhesive with a certain hardness is usually selected and applied to one end of the flexible tube 10 by a dispensing machine. The flexible tube 10 is filled with soft adhesive 60. By overfilling the flexible tube 10, the soft adhesive 60 completely fills all the space inside the flexible tube 10 and seals the other end of the flexible tube 10. The material of the soft adhesive 60 can be silicone or other polymer materials, which can achieve softness after curing. The lead wire 41 reserved on the chip 40 passes through the other end of the flexible tube 10 for transmitting electrical signals.

[0026] To ensure that the soft glue 60 fully fills all the space inside the tube 10, a sufficient amount of soft glue 60 is injected into the tube 10 using an overfilling method. Since the overflow of soft glue is uncontrollable, it can fill a sufficiently long tube 10. When a small amount of soft glue is found to overflow outside the tube, the injection of soft glue is stopped and curing is carried out. After curing, since the length of the fully injected tube is long enough, and the tube at the installation location of the titanium base 20 and the chip 40 is of sufficient length, a certain length of tube is cut off from both ends of the tube 10. The curing process can be completed by standing at 150°C for one hour or standing at 25°C for three days.

[0027] In the actual manufacturing process, before filling the soft glue 60 into the tube 10, biocompatible adhesive 50 can be applied to one end of the tube 10 to form a smooth probe head structure. Then, soft glue 60 is poured into the tube 10 from the other end, using an overfilling method to pour a sufficient amount of soft glue 60 into the tube 10 and fill the tube 10 to a sufficient length. When a small amount of soft glue is found to overflow from the other end of the tube, the pouring of soft glue is stopped and the tube is allowed to cure. After curing, ensuring that the tube at the titanium base 20 and chip 40 mounting locations is of sufficient length, a certain length of tube is cut off from the other end of the tube 10. To avoid cutting the lead wire 41, a transparent tube can be used, or a base can be fixed at a certain distance from the tube opening, and the tube can be cut off at a certain distance from the tube opening.

[0028] like Figure 2 As shown, in the prior art, a hole for sensing intracranial pressure needs to be opened on the surface of the pressure sensor chip, and an open-type glue filling method is used to cover the hole with glue. To ensure biocompatibility, a sufficiently thick glue needs to be coated at the hole, with an actual thickness of about 500 micrometers. In order to reduce the thickness deviation in the multiple glue coating process, the consistency of each coating must be ensured. This places extremely high demands on the control precision of the dispensing machine. Once the control precision of the dispensing machine deviates, it will cause changes in the glue coverage thickness. The open-type glue filling method often results in an uneven surface and uneven thickness of the soft glue. Changes in glue coverage thickness will directly cause changes in the pressure transmission value, resulting in poor sensor consistency and making the calibration and testing process more complicated. Excessively thick glue will also affect the performance of the sensor, thereby reducing the measurement accuracy of the intracranial pressure sensor.

[0029] This invention does not employ the traditional method of exposing the adhesive coating on the sensor surface to the testing environment; instead, it places the pressure sensor chip inside a flexible tube, such as... Figure 3 As shown, this utility model uses a flexible tube 10 with a fixed and controllable diameter to confine the pressure-transmitting soft glue 60 inside the flexible tube 10 with a fixed diameter. Then, the entire tube is filled with glue. By utilizing the consistency of the tube diameter, the surface of the soft glue on the upper surface of the chip 40 is flat, with uniform thickness and precise controllability. Compared with the existing open glue filling method, the thickness of the soft glue in this utility model is precisely controllable, which can ensure the measurement accuracy of the intracranial pressure sensor.

[0030] Throughout the entire structure, the diameter of the flexible tube is precisely controllable, and the size and thickness of the chip are precisely controllable to the micrometer scale. Therefore, the structure and dimensions of the entire system, except for the filler adhesive, are all precise. For the filler adhesive, which serves as the pressure transmission medium, an overfilling method is used, allowing excess adhesive to automatically flow out, to ensure consistent adhesive filling.

[0031] Furthermore, the titanium base 20 of this invention is located inside the closed flexible tube 10, so there is no need to worry about the base falling off during use, ensuring the safety of the intracranial pressure sensor. Moreover, the titanium base does not need to be precision machined into a ring structure for the bayonet pressure sensor wiring harness, which greatly reduces the technical difficulty and cost of sensor processing.

[0032] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A packaging structure for an intracranial pressure monitoring pressure sensor probe, characterized in that: The device includes a flexible tube (10), a titanium base (20), and a chip (40). The chip (40) is fixed on the titanium base (20), which is attached to the flexible tube (10). One end of the flexible tube (10) is coated with biocompatible adhesive (50), and the flexible tube (10) is filled with soft glue (60) and the other end of the flexible tube (10) is sealed. The lead wire (41) on the chip (40) passes through the other end of the flexible tube (10).

2. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 1, characterized in that: The hose (10) has a circular cross-section, and the titanium base (20) has a semi-circular cross-section with the same curvature as the hose (10).

3. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 1 or 2, characterized in that: The lower surface of the titanium base (20) is attached to the inner wall of the hose (10), and the chip (40) is fixed to the upper surface of the titanium base (20).

4. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 3, characterized in that: The lower surface of the titanium base (20) is bonded to the inner wall of the flexible tube (10) by die bonder (30), and the chip (40) is bonded to the upper surface of the titanium base (20) by die bonder (30).

5. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 4, characterized in that: The thickness of the die bond adhesive (30) is 100μm-500μm.

6. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 1, characterized in that: The hoses (10) at both ends of the titanium base (20) at the installation position are reserved with a set length.

7. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 1, characterized in that: The end of the hose (10) at the installation position of the titanium base (20) is coated with biocompatible adhesive (50), and the end of the hose (10) at the other end is reserved with a set length.

8. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 1, characterized in that: The end of the flexible tube (10) coated with biocompatible adhesive (50) has a smooth structure.

9. The intracranial pressure monitoring pressure sensor probe packaging structure according to claim 1, characterized in that: The soft rubber (60) is the medium for transmitting pressure.

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