CN112022088A - Variable capacitance intraocular pressure sensor based on microfluidics technology and system thereof - Google Patents
Variable capacitance intraocular pressure sensor based on microfluidics technology and system thereof Download PDFInfo
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- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B3/16—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for measuring intraocular pressure, e.g. tonometers
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Abstract
A variable capacitance intraocular pressure sensor and a system thereof based on microfluidics technology, wherein the variable capacitance intraocular pressure sensor comprises: the corneal contact lens comprises two films and an inner space formed by the two films; a variable capacitance element built in an inner space of the contact lens; the distance between the electrode plates of the variable capacitance element is a microfluid gap; the spiral inductor is arranged in the inner space of the corneal contact lens and is connected with the variable capacitance element to form an RLC loop; wherein the interior space of the contact lens further comprises a microfluidic reservoir chamber filled with a fluid; when the corneal contact lens is deformed due to the influence of pressure, fluid in the microfluid liquid storage chamber is injected into the microfluid gap or is extracted from the microfluid gap, the capacitance value of the variable capacitance element is changed, the change of the resonance frequency is caused, and intraocular pressure detection is realized. The intraocular pressure sensor can be used for continuous and noninvasive intraocular pressure monitoring and has the characteristics of simple structure, low resonant frequency and high sensitivity.
Description
Technical Field
The invention relates to the field of medical instruments, in particular to a capacitance-variable intraocular pressure sensor based on a microfluid technology and a system thereof.
Background
Intraocular pressure (IOP), which is the pressure of the eye, is the equilibrium pressure exerted by the eyeball contents on the eyeball wall, and is one of the important indicators for judging the health of the eye. The traditional intraocular pressure monitoring method cannot continuously monitor intraocular pressure, is difficult to truly reflect the actual change condition of intraocular pressure, and limits further research and exploration of ocular diseases caused by intraocular pressure. At present, an effective method and means for non-invasive continuous monitoring of intraocular pressure fluctuation are lacked at home and abroad, and most of intraocular pressure fluctuation changes at the level of single measurement of the traditional intraocular pressure. Therefore, the research of the key technology of noninvasive and continuous intraocular pressure monitoring and the establishment of a noninvasive and wireless continuous intraocular pressure monitoring system have extremely important medical significance and social significance.
Several units and research institutions now propose sensitive wearable intraocular pressure sensors that utilize electrical properties integrated on a corneal contact lens. As the intraocular pressure increases, the expanding cornea will cause the attached flexible contact lens to deform in unison, causing the internal sensing element to deform, which in turn causes its electrical properties to change. Intraocular pressure sensors currently under development are largely classified into resistive intraocular pressure sensors, capacitive intraocular pressure sensors, and inductive intraocular pressure sensors, depending on the sensing element used. The resistance type intraocular pressure sensor is a resistance strain sensor designed based on the Wheatstone bridge principle, the resistance of the bridge can change along with the deformation of the cornea, and the voltage fluctuation caused by the change of the bridge is read through a precise amplifying circuit. Research on a resistance type intraocular pressure sensor has been carried out since a long time abroad, and a resistance type intraocular pressure monitoring sensor was developed by sensory corporation of switzerland in 2009. The sensor is provided with two annular platinum-titanium resistance strain gauges which form a Wheatstone bridge together with two other temperature compensation platinum-titanium resistors with fixed resistance values. The integrated circuit chip embedded in the contact lens and the antenna can be matched with an external reading device to realize wireless reading of data. The device is now commercialized by the company Sensimed and sold in the form of a Sensimed Triggerfish smart contact lens. However, in the clinical test process, the rigidity of the reading chip is high, so that symptoms such as corneal swelling and the like are easily caused, and certain potential safety hazards exist.
Capacitive intraocular pressure sensors and inductive intraocular pressure sensors are based on the detection principle of LC resonance circuits, and when the inductance or capacitance value of the sensor changes along with the deformation of the cornea, the resonance frequency of the circuit also changes, and the change of the resonance frequency can be detected by using a vector network analyzer, so that the change of the intraocular pressure is indirectly read. Guo-Zhen Chen et al, university of hong Kong, developed a capacitive intraocular pressure transducer that accurately tracked changes in intraocular pressure via ex vivo porcine eye testing. Over the years, the team developed an inductive tonometer sensor that accurately tracked changes in tonus, but was less sensitive than capacitive. The two methods do not need to be combined with reading of an IC, can be read only by combining a reading coil with a vector network analyzer, are simple to operate and low in cost, and can improve comfort.
However, most of the existing capacitive intraocular pressure sensors change the capacitance value of the sensor by changing the spacing between the parallel plate capacitors or the facing area, and the change is very weak, so that the sensitivity of the sensor is low.
Disclosure of Invention
In view of the above, the present invention is directed to a variable capacitance intraocular pressure sensor based on micro-fluidic technology and a system thereof, which are designed to at least partially solve at least one of the above-mentioned problems.
In order to achieve the purpose, the technical scheme of the invention comprises the following steps:
as an aspect of the present invention, there is provided a variable capacitance intraocular pressure sensor based on a microfluidic technique, comprising:
the corneal contact lens comprises two films and an inner space formed by the two films;
a variable capacitance element built in an inner space of the contact lens; the distance between the electrode plates of the variable capacitance element is a microfluid gap;
the spiral inductor is arranged in the inner space of the corneal contact lens and is connected with the variable capacitance element to form an RLC loop;
wherein the interior space of the contact lens further comprises a microfluidic reservoir chamber filled with a fluid; when the corneal contact lens is deformed under the influence of pressure, fluid in the microfluid liquid storage chamber is injected into the microfluid gap or is extracted from the microfluid gap, the capacitance value of the variable capacitance element is changed, the change of the resonance frequency is caused, and intraocular pressure detection is realized.
As another aspect of the present invention, there is also provided a variable capacitance intraocular pressure sensing system based on microfluidics, comprising: the variable capacitance intraocular pressure sensor, the reading coil and the detection device as described above;
the RLC loop formed by the variable capacitance element and the spiral inductor detects the change of the resonant frequency of the loop through an external reading coil and detection equipment, and then detects the change of intraocular pressure;
preferably, the detection device comprises a vector network analyzer or an impedance analyzer.
Based on the technical scheme, compared with the prior art, the invention has at least one or one part of the following beneficial effects:
(1) compared with the traditional variable-capacitance intraocular pressure sensor, the variable-capacitance intraocular pressure sensor has the advantages that the capacitance change of the variable capacitance element is caused by the fact that fluid flows under the pressure change, and based on the microfluid technology, the microfluid liquid storage chamber and the microfluid gap of the variable capacitance element are both miniaturized, the variable-capacitance intraocular pressure sensor has larger variation amplitude than the variable capacitance formed only by geometric deformation, and the high sensitivity is realized;
(2) the invention realizes the passivity of the intraocular unit of the intraocular pressure detection system, avoids the inevitable complicated insulating packaging and other technological processes of active devices, and reduces the technological difficulty;
(3) the invention utilizes the combination of an external reading coil and a vector network analyzer to read the change of the capacitance of the sensor, so that the whole measuring system is very simple;
(4) the metal plate is annular, and the middle part of the metal plate is a circular transparent area, so that pupils cannot be shielded, and the vision of a patient cannot be influenced when the metal plate is worn;
(5) the detection equipment is a vector network analyzer or an impedance analyzer, is portable, and can realize continuous detection;
(6) the capacitance intraocular pressure sensor changes the capacitance value by changing the dielectric constant, and the sensitivity is improved;
(7) the variable capacitance element has the advantages that the opposite area of the two layers of metal plates is large, the plate interval is small, so that a larger capacitance value is obtained, the resonance frequency of a loop is reduced, and the safety performance of the sensor is improved.
Drawings
FIG. 1 is a perspective view of a variable capacitance intraocular pressure sensor based on microfluidic technology in accordance with an embodiment of the present invention;
FIG. 2 is a schematic cross-sectional view of a variable capacitance intraocular pressure sensor based on microfluidics according to an embodiment of the present invention;
FIG. 3 is a schematic partial cross-sectional view of a variable capacitance intraocular pressure sensor based on microfluidic technology according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a variable capacitance intraocular pressure sensing system based on microfluidics.
In the above figures, the reference numerals have the following meanings:
1. a variable capacitance intraocular pressure sensor; 10. a corneal contact lens; 101. a microfluidic reservoir chamber; 102. a chamber support layer; 20. a variable capacitance element; 201. a support insulating layer; 202. a microfluidic gap; 30. a spiral inductor; 2. a reading coil; 3. a radio frequency transmission cable; 4. a vector network analyzer; 5. and (4) a computer.
Detailed Description
The capacitance-variable intraocular pressure sensor based on the microfluid technology has the advantages that the structure is simple, the deformation of the microfluid liquid storage chamber is sensitive, the liquid between the two electrode plates can flow back to the microfluid liquid storage chamber more completely due to the simultaneous action of pressure and self gravity, and the accuracy of intraocular pressure cycle monitoring is improved. In addition, the variable capacitance value of the structure provided by the invention is far greater than that of the sensor in the prior art, so that the resonant frequency of the loop is greatly reduced, and the harm of high-frequency radiation to human bodies is reduced.
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
As an aspect of the present invention, there is provided a variable capacitance intraocular pressure sensor based on a microfluidic technique, comprising:
the corneal contact lens comprises two films and an inner space formed by the two films;
a variable capacitance element built in an inner space of the contact lens; the distance between the electrode plates of the variable capacitance element is a microfluid gap;
the spiral inductor is arranged in the inner space of the corneal contact lens and is connected with the variable capacitance element to form an RLC loop;
wherein the interior space of the contact lens further comprises a microfluidic reservoir chamber filled with a fluid; when the corneal contact lens is deformed due to the influence of pressure, fluid in the microfluid liquid storage chamber is injected into the microfluid gap or is extracted from the microfluid gap, the capacitance value of the variable capacitance element is changed, the change of the resonance frequency is caused, and intraocular pressure detection is realized.
In an embodiment of the present invention, a variable capacitance element includes two electrode plates, a supporting insulating layer; wherein the content of the first and second substances,
the two layers of electrode plates are annular and arranged in parallel at intervals;
the supporting insulating layer is in a ring shape and is arranged between the two electrode plates, so that the two electrode plates form a parallel plate capacitor;
wherein, a micro-fluid gap is formed between the two electrode plates.
In an embodiment of the present invention, the electrode plate includes a gold material or a copper material; the supporting insulating layer is made of insulating materials;
the supporting insulating layer includes a polybutylene adipate/terephthalate material, a polydimethylsiloxane material, or a polyethylene terephthalate material.
In an embodiment of the present invention, the size of the electrode plate is: the inner radius is 2mm, the outer radius is 6mm, and the thickness is 10 μm; size of the supporting insulating layer: the inner radius is 4mm, the outer radius is 6mm, and the thickness is 30-80 μm.
The inner radius and the outer radius of the electrode plate and the supporting insulating layer are not limited to the inner radius and the outer radius, and on one hand, the inner hole of the semicircular ring can penetrate through the pupil without blocking the sight; on the other hand, the opposite area of the two electrode plates is large.
The thickness of the supporting insulating layer determines the microfluidic gap of the variable capacitance element, and the distance between the plates is preferably 30 to 80 μm, more preferably 50 μm.
In a preferred embodiment of the invention, the dimensions of the electrode plates are: the inner radius is 2mm, the outer radius is 6mm, and the thickness is 10 μm; size of the supporting insulating layer: the inner radius is 4mm, the outer radius is 6mm, and the thickness is 50 μm.
In the embodiment of the invention, the spiral inductor is connected with one of the two layers of electrode plates;
the spiral inductor comprises a gold or copper material;
the thickness of the spiral inductor is 10 μm.
In an embodiment of the invention, the corneal contact lens is configured to be transparent and flexible;
the material of the corneal contact lens comprises polydimethylsiloxane, siloxane methacrylate, fluorosilicone acrylate or polymethacrylate.
In an embodiment of the present invention, the variable capacitance intraocular pressure sensor further includes a chamber supporting layer, the chamber supporting layer is disposed between a film layer of the contact lens and the variable capacitance element, and is configured to surround the film layer of the contact lens to form a microfluidic liquid storage chamber;
wherein the chamber support layer comprises Parylene, SU-8 photoresist, or polyimide material.
In an embodiment of the present invention, the chamber support layer has an inner radius of 4mm, an outer radius of 6mm, and a height of 80 μm to 120 μm.
Wherein, the inner radius and the outer radius of cavity supporting layer, not being restricted to this, as long as can realize that the hole of semicircle ring can see through the pupil, do not shelter from the sight.
Wherein the thickness of the chamber support layer determines the thickness of the microfluidic chamber, suitably between 80 μm and 120 μm, preferably 100 μm.
In a preferred embodiment of the invention, the chamber support layer has an inner radius of 4mm, an outer radius of 6mm and a height of 100 μm.
In the embodiment of the invention, the fluid filled in the microfluid liquid storage chamber is pure water or glycerol;
and carrying out hydrophobic treatment on the inner wall of the microfluid liquid storage chamber.
In an embodiment of the invention, the corneal contact lens has a diameter of 14mm and a thickness after encapsulation of not more than 500 μm.
As another aspect of the present invention, there is also provided a variable capacitance intraocular pressure sensing system, comprising the variable capacitance intraocular pressure sensor as described above, a reading coil and a detection device;
the RLC loop formed by the variable capacitance element and the spiral inductor detects the change of the resonant frequency of the loop through an external reading coil and detection equipment so as to detect the change of intraocular pressure;
in an embodiment of the invention, the detection device may be a vector network analyzer or an impedance analyzer.
The technical solution of the present invention is further described below with reference to specific examples, but it should be noted that the following examples are only for illustrating the technical solution of the present invention, but the present invention is not limited thereto.
According to an embodiment of the present invention, there is provided a variable capacitance intraocular pressure sensor based on a microfluidic technology, and fig. 1 is a perspective view of the variable capacitance intraocular pressure sensor based on the microfluidic technology according to the embodiment of the present invention; fig. 2 is a schematic diagram of an internal structure of a variable capacitance intraocular pressure sensor based on a micro-fluidic technology, and fig. 3 is a schematic partial cross-sectional diagram of the variable capacitance intraocular pressure sensor based on the micro-fluidic technology according to an embodiment of the present invention; as shown in fig. 1, 2 and 3, the variable capacitance intraocular pressure sensor 1 includes:
a liquid-filled microfluidic reservoir chamber 101 for providing a liquid dielectric to the variable capacitance element 20 to change a capacitance value of the variable capacitance element 20;
the corneal contact lens 10 is used for providing a substrate material for the microfluidic liquid storage chamber 101, and simultaneously packaging the whole sensor device to form a spherical crown shape which is tightly attached to an eyeball;
the corneal contact lens 10 is used for conveying liquid dielectric into the microfluidic gap 202 in the variable capacitance element 20 by following the deformation of the intraocular pressure and causing the deformation of the volume of the microfluidic liquid storage chamber 101, so as to cause the capacitance value of the variable capacitance element 20 to change;
and a spiral inductor 30 for connecting with the variable capacitance element 20 to form an RLC loop for detecting the change of the intraocular pressure.
Wherein, the corneal contact lens 10 is directly worn on the cornea of the eye, is prepared by transparent flexible materials, and the materials are one of the following materials: polydimethylsiloxane, siloxane methacrylate, fluorosilicone acrylate or polymethacrylate, but the material is not limited to the above, and can be other common corneal contact lens materials as long as the material is transparent, flexible and comfortable to wear.
As shown in fig. 2 and 3, the contact lens 10 of the present invention is made of two pieces of contact lens materials, the first piece needs to be used as a substrate of the microfluidic liquid storage chamber 101, and the other piece needs to encapsulate the upper surface of the whole device, and it is considered that a thermoplastic process is used in combination with a self-made mold to encapsulate the two pieces of contact lens materials together and form a spherical cap shape.
The microfluidic liquid storage chamber 101 uses a bottom layer corneal contact lens material as a substrate, and a wall of a circular ring-shaped liquid storage chamber, namely a chamber support layer 102, is prepared by selecting a Parylene (Parylene), SU-8 photoresist or Polyimide (PI) material through processes such as photoetching or plasma etching; the chamber support layer 102 has an inner radius of 4mm, an outer radius of 6mm and a height of 100 μm.
The liquid microfluid in the microfluid liquid storage chamber 101 needs to be liquid with high dielectric constant and no harm to human eyes, such as glycerol or pure water.
The variable capacitance element 20 is a parallel plate capacitor formed by two layers of circular metal plates and a middle circular support insulating layer 201; the two layers of annular metal plates are made of gold materials or copper materials through an electroplating process, the inner radius is 2mm, the outer radius is 6mm, and the thickness is 10 mu m; the middle annular supporting insulating layer 201 is made of one of ecoflex materials, PDMS or PET materials, the inner diameter is 4mm, the outer diameter is 6mm, and the thickness is 50 μm.
The spiral inductor 30 is made of a gold material or a copper material by electroplating, is connected with the bottom metal plate of the variable capacitance element 20, and has an inner radius of 6.2mm, an outer radius of 6.4mm, and a thickness of 10 μm.
The variable capacitance element 20 and the spiral inductor 30 form an RLC loop, and the change of the intraocular pressure can be detected from the change of the loop resonance frequency.
The microfluidic storage chamber 101 needs to be subjected to a hydrophobic treatment, such as vapor deposition of a layer of Parylene with a thickness of 5 μm on the inner wall of the microfluidic storage chamber 101 or silylation of the inner wall surface of the microfluidic storage chamber 101.
Wherein the corneal contact lens 10 has a diameter of 14mm and a thickness of not more than 500 μm after encapsulation.
Fig. 4 shows a variable capacitance intraocular pressure sensing system based on microfluidics, which comprises a variable capacitance intraocular pressure sensor 1, a reading coil 2, a radio frequency transmission cable 3, a vector network analyzer 4 and a computer 5. When in measurement, firstly, the variable capacitance type intraocular pressure sensor 1 device is placed on the cornea of a user, namely the surface of an eyeball, then the reading coil 2 is connected with the vector network analyzer 4 through the radio frequency transmission cable 3, and then the reading coil 2 is placed outside the eye provided with the variable capacitance type intraocular pressure sensor 1 in a close-distance and parallel manner, the increase of the intraocular pressure causes glycerin in the microfluid liquid storage chamber 101 to enter a microfluid gap 202 in the variable capacitance element 20, thereby causing the dielectric material of the variable capacitance element 20 to be changed from air into liquid dielectric with high dielectric constant, and causing the capacitance value of the variable capacitance element 20 to be greatly changed; the vector network analyzer 4 is connected with the reading coil 2 through the radio frequency transmission cable 3 to detect the change of the resonant frequency of the variable capacitance intraocular pressure transducer 1. The resonant frequency of the RLC loop can be read at the vector network analyzer 4, the vector network analyzer 4 is connected to the computer 5, and the data is recorded, stored and analyzed by the computer 5, so that the intraocular pressure change can be continuously monitored in real time.
The variable capacitance element 20 changes the capacitance value by changing the dielectric constant, has high sensitivity, can detect a minute fluctuation in intraocular pressure, and obtains the detection result by the vector network analyzer 4.
In summary, the present invention provides a capacitive sensor integrated on a contact lens and using a microfluidic technology to change a capacitive dielectric, aiming at the characteristics that intraocular pressure changes can cause deformation of a cornea and further cause deformation of an electrical element on the contact lens, and deformation at the junction of a corner and a sclera is the largest. The change of the rise and fall of the intraocular pressure can cause the eyeball, especially the change of the size of the corneal curvature, and then the change of the curvature of the corneal contact lens attached on the intraocular pressure can be caused, the microfluid liquid storage chamber integrated on the corneal contact lens can deform accordingly, the change can cause the liquid in the microfluid liquid storage chamber to enter the microfluid gap of the variable capacitance element, and further the change of the capacitance value can be caused greatly. The variable capacitance element is connected with the spiral inductor to form an RLC loop, and the vector network analyzer can detect the change of the resonant frequency of the sensor loop through an external reading coil, so that the small fluctuation of intraocular pressure can be detected. The mode realizes long-term monitoring by wearing the corneal contact lens once, thereby greatly improving the wearing comfort; the passivity of the intraocular unit of the intraocular pressure detection system is realized, and the inevitable complicated insulating packaging and other technological processes of active devices are avoided; the higher capacitance value of the variable capacitor reduces the resonance frequency of detection and increases the safety of the device; the capacitance variation of the capacitive sensor is greatly improved by changing the capacitance dielectric substance, and the sensitivity of the sensor is further improved.
It will be appreciated that the detection algorithms, analysis, and displays provided herein are not inherently related to any particular computer, virtual machine, or other apparatus. Various general purpose systems may also be used with the teachings herein. Moreover, the present invention is not directed to any particular programming language. It is appreciated that a variety of programming languages may be used to implement the teachings of the present invention as described herein, and any descriptions of specific languages are provided above to disclose the best mode of the invention.
The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some or all of the components in the associated apparatus according to embodiments of the invention. The present invention may also be embodied as apparatus or device programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present invention may be stored on computer-readable media or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A variable capacitance intraocular pressure sensor based on microfluidics, comprising:
the corneal contact lens comprises two films and an inner space formed by the two films;
a variable capacitance element built in an inner space of the contact lens; the distance between the electrode plates of the variable capacitance element is a microfluid gap;
the spiral inductor is arranged in the inner space of the corneal contact lens and is connected with the variable capacitance element to form an RLC loop;
wherein the interior space of the contact lens further comprises a microfluidic reservoir chamber filled with a fluid; when the corneal contact lens is deformed under the influence of pressure, fluid in the microfluid liquid storage chamber is injected into the microfluid gap or is extracted from the microfluid gap, the capacitance value of the variable capacitance element is changed, the change of the resonance frequency is caused, and intraocular pressure detection is realized.
2. The variable capacitance intraocular pressure sensor according to claim 1, wherein the variable capacitance element comprises two layers of electrode plates, a supporting insulating layer; wherein the content of the first and second substances,
the two layers of electrode plates are annular and arranged in parallel at intervals;
the supporting insulating layer is in a ring shape and is arranged between the two electrode plates, so that the two electrode plates form a parallel plate capacitor;
wherein, a micro-fluid gap is formed between the two electrode plates.
3. The variable capacitance intraocular pressure transducer of claim 2, wherein: the electrode plate comprises a gold material or a copper material; the support insulating layer comprises a polybutylene adipate/terephthalate material, a polydimethylsiloxane material or a polyethylene terephthalate material.
4. The variable capacitance intraocular pressure transducer of claim 3, wherein: the thickness of the supporting insulating layer is 30-80 μm.
5. The variable capacitance intraocular pressure transducer of claim 2, wherein:
the spiral inductor is connected with one of the two layers of electrode plates;
the spiral inductor comprises a gold or copper material;
the thickness of the spiral inductor is 10 mu m.
6. The variable capacitance intraocular pressure transducer of claim 1, wherein: the corneal contact lens is transparent and flexible;
the corneal contact lens is made of polydimethylsiloxane, siloxane methacrylate, fluorosilicone acrylate or polymethacrylate.
7. The variable capacitance intraocular pressure transducer of claim 1, wherein: the variable capacitance intraocular pressure sensor further comprises a chamber supporting layer, wherein the chamber supporting layer is arranged between a film layer of the corneal contact lens and the variable capacitance element and used for surrounding the film layer of the corneal contact lens to form the microfluidic liquid storage chamber;
wherein the chamber support layer comprises parylene, photoresist, or polyimide material;
the height of the chamber supporting layer is 80-120 mu m.
8. The variable capacitance intraocular pressure transducer of claim 1, wherein: the fluid filled in the microfluid liquid storage cavity is pure water or glycerol;
and carrying out hydrophobization treatment on the inner wall of the microfluid liquid storage chamber.
9. The variable capacitance intraocular pressure transducer of claim 1, wherein: the thickness of the packaged cornea contact lens is not more than 500 mu m.
10. A variable capacitance intraocular pressure sensing system based on microfluidics, comprising: the variable capacitance intraocular pressure sensor, the reading coil and the detection device according to any one of claims 1 to 9;
the RLC loop formed by the variable capacitance element and the spiral inductor detects the change of the resonant frequency of the loop through an external reading coil and detection equipment, and then detects the change of intraocular pressure;
preferably, the detection device comprises a vector network analyzer or an impedance analyzer.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115969312A (en) * | 2023-03-22 | 2023-04-18 | 中国人民解放军总医院第一医学中心 | Intraocular pressure monitoring device connected with glaucoma drainage valve |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6939299B1 (en) * | 1999-12-13 | 2005-09-06 | Kurt Petersen | Implantable continuous intraocular pressure sensor |
| CN105919551A (en) * | 2016-04-13 | 2016-09-07 | 华中科技大学 | Micro-fluid technique based non-implantable intraocular pressure detection sensor |
| CN105962887A (en) * | 2016-04-13 | 2016-09-28 | 华中科技大学 | Non-invasive ocular pressure detection sensor based on micro-fluidic technology |
| CN110292352A (en) * | 2019-07-12 | 2019-10-01 | 华中科技大学 | A kind of power transformation sense wireless type intraocular pressure monitoring sensor based on microfibre pipe |
| CN110292351A (en) * | 2019-07-12 | 2019-10-01 | 华中科技大学 | Change inductance type contact lenses intraocular pressure sensor and its preparation based on microfluid electronics |
-
2020
- 2020-09-09 CN CN202010943908.1A patent/CN112022088A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6939299B1 (en) * | 1999-12-13 | 2005-09-06 | Kurt Petersen | Implantable continuous intraocular pressure sensor |
| CN105919551A (en) * | 2016-04-13 | 2016-09-07 | 华中科技大学 | Micro-fluid technique based non-implantable intraocular pressure detection sensor |
| CN105962887A (en) * | 2016-04-13 | 2016-09-28 | 华中科技大学 | Non-invasive ocular pressure detection sensor based on micro-fluidic technology |
| CN110292352A (en) * | 2019-07-12 | 2019-10-01 | 华中科技大学 | A kind of power transformation sense wireless type intraocular pressure monitoring sensor based on microfibre pipe |
| CN110292351A (en) * | 2019-07-12 | 2019-10-01 | 华中科技大学 | Change inductance type contact lenses intraocular pressure sensor and its preparation based on microfluid electronics |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115969312A (en) * | 2023-03-22 | 2023-04-18 | 中国人民解放军总医院第一医学中心 | Intraocular pressure monitoring device connected with glaucoma drainage valve |
| CN115969312B (en) * | 2023-03-22 | 2023-08-22 | 中国人民解放军总医院第一医学中心 | Intraocular pressure monitoring device connected with glaucoma drainage valve |
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