Corneal contact lens type eyelid pressure measuring system

Abstract

The utility model provides a corneal contact lens type eyelid pressure measuring system which structurally comprises a contact lens which structurally comprises a capacitive pressure sensor, a sensing coil and a packaging layer. The contact lens is worn between eyeballs and eye sockets of a testee and used for acquiring eyelid pressure signals and converting the eyelid pressure signals into electric signals. And the external energy supply receiving device is wirelessly connected with the contact lens, structurally comprises a transmitting coil and a receiving coil, and is used for supplying energy to the contact lens and receiving an electric signal sent by the contact lens. The signal analysis device is connected with the external energy supply receiving device, and the signal analysis device derives the relationship between the frequency and the energy transmission efficiency by analyzing the input reflection coefficient on the transmitting coil and the reverse transmission coefficient on the receiving coil, and determines the resonant frequency of the system, so as to obtain a capacitance change value; and then the pressure value of the eyeballs of the testee is obtained through the capacitance-pressure relation curve.

Description

Technical Field

[0001] The utility model relates to a contact lens and a pressure sensor, in particular to a contact lens type eyelid pressure measurement system. Background Art

[0002] Existing eyelid pressure detection systems are various, but all have certain defects and cannot be clinically promoted. The existing eyelid pressure detection systems usually have the following problems: 1. It is necessary to hold the sensor by hand for measurement, and there is a wired connection between the sensor and the signal receiving system. The overall volume of the system is relatively large, and the operation convenience is not high. 2. It is necessary to insert the thin film sensor between the eyelid and the eyeball of the subject, and the comfort level is relatively low, resulting in low cooperation and poor compliance of the subject, and a long detection time. 3. Since the pressure sensors are all flat, there is always an angle between the contact surface with the cornea or conjunctiva during measurement, and it is impossible to ensure the consistency of pressure measurement. 4. The thickness of the sensor may stimulate the corneal and eyelid surfaces, and may cause reflexive contraction of the eyelid muscles even under anesthesia. 5. The insertable pressure sensor will also inevitably cause incomplete eyelid closure of the subject during measurement, and cannot simulate the eye condition under physiological conditions, resulting in measurement errors.

[0003] In addition, at present, the eyelid pressure measurement technology has not formed an industry standard, the wireless eyelid pressure measurement technology has not been deeply studied, and there is no unified consensus clinically. The wired eyelid pressure measurement technology will make devices such as wires contact with the eyelids of the subject, bringing many inconveniences to the subject. Content of the Utility Model

[0004] In view of the above-mentioned many technical problems, the utility model provides a contact lens type eyelid pressure measurement device, which realizes more accurate, convenient, stable and efficient eyelid pressure measurement.

[0005] The technical solution adopted by the utility model is as follows:

[0006] A contact lens type eyelid pressure measurement system, characterized by comprising:

[0007] A contact lens, the structure of which includes a capacitive pressure sensor, a sensing coil and a packaging layer. The contact lens is worn between the eyeball and the eyelid of the subject, and is used to acquire eyelid pressure signals and convert them into electrical energy signals;

[0008] An external energy supply and receiving device, which is wirelessly connected to the contact lens, and is used to supply energy to the contact lens and receive the electrical energy signals sent by the contact lens;

[0009] A signal analysis device, which is used to analyze the received electrical energy signals to obtain the pressure value of the subject's eyelid;

[0010] The capacitive pressure sensor includes:

[0011] The base layer has two upper and lower layers;

[0012] The capacitor plate layer has two layers, which are respectively arranged on one side of the upper and lower base layers;

[0013] The middle pressure sensing layer is arranged between the two capacitor plate layers. When pressure is applied, the thickness of the middle pressure sensing layer will change with the magnitude of the applied pressure;

[0014] The sensing coil is a nano - silver coil formed by a random network using a hybrid nanostructure based on AgNFs and AgWFs. The sensing coil is connected to the capacitor plate layer to form a sensing communication circuit.

[0015] The signal analysis device includes a vector network analyzer.

[0016] The capacitive pressure sensor has high transparency and strong light transmittance, and its surface can cover the entire pupil range of the subject.

[0017] The middle pressure sensing layer uses an Ecoflex 0030 film with a low elastic modulus.

[0018] The material used for the capacitor plate layer is highly transparent reduced graphene oxide.

[0019] The base layer uses pHEMA material, and the encapsulation layer uses a silicone gel with properties similar to pHEMA.

[0020] The main body of the nano - silver coil is an electrospun fiber prepared from AgNFs, and the AgNWs material is used to fill the gaps between the networks formed by the electrospun fibers.

[0021] The external energy supply receiving device is provided with a transmitting coil and a receiving coil.

[0022] The external energy supply receiving device transfers energy through the principle of electromagnetic induction, transfers the energy on the transmitting coil to the sensing coil in the contact lens, and the alternating current in the coil is converted into direct current through rectification and filtering to provide electrical energy for the sensing communication circuit.

[0023] The beneficial effects of the present utility model are as follows: The eyelid pressure data measured in the present utility model depends on the input reflection coefficient and reverse transmission coefficient constructed by the input signal on the transmitting coil and the output signal on the receiving coil. Such a measurement method reduces the mutual interference between signal energy transmission and signal detection, making the obtained data more accurate. The capacitive pressure sensor and the sensing coil made of nano - silver material used in the present utility model also ensure the rapid signal transmission, further reducing the error of the detection result. Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of a contact lens type eyelid pressure measurement system;

[0025] Figure 2 It is a schematic diagram of an embodiment of a contact lens and an external energy supply receiving device;

[0026] Figure 3 It is a schematic structural diagram of a contact lens;

[0027] Figure 4 It is a schematic structural diagram of a capacitive pressure sensor;

[0028] Figure 5 It is a schematic diagram of a power supply circuit between an external energy supply receiving device and a contact lens;

[0029] Figure 6 It is a schematic diagram of an energy signal receiving circuit between an external energy supply receiving device and a contact lens;

[0030] Figure 7 It is a schematic flow diagram of a contact lens type eyelid pressure measurement system.

[0031] In the figure: 1. Capacitive pressure sensor; 11. Base layer; 12. Capacitor plate layer; 13. Intermediate pressure sensing layer; 2. Sensing coil; 3. Encapsulation layer. Specific embodiments

[0032] Next, the technical solutions in this embodiment will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are partial embodiments of the present invention rather than all embodiments.

[0033] As Figure 1 、 Figure 2 shown, the present invention includes a contact lens, an external energy supply receiving device, and a signal receiving device. The contact lens is worn between the cornea and the eyelid of the subject's eyeball, and is used to acquire the eyelid pressure signal and convert it into an electrical signal; the external energy supply receiving device is wirelessly connected to the contact lens, and its shape is a glasses or eye mask type device, and it contains a transmitting coil and a receiving coil inside. When in use, it is set outside the subject's eyelid, and is used to supply energy to the contact lens and receive the electrical signal sent by the contact lens; the signal analysis device is connected to the external energy supply receiving device, and is used to deduce the relationship between the frequency and the energy transmission efficiency by analyzing the input reflection coefficient received from the transmitting coil and the reverse transmission coefficient received from the receiving coil, and determine the resonance frequency of the system, so as to obtain the capacitance value, and then obtain the pressure value of the subject's eyeball through the capacitance-pressure relationship curve.

[0034] As Figure 3As shown, the contact lens structure includes a capacitive pressure sensor 1, a sensing coil 2, and a packaging layer 3. The capacitive pressure sensor 1 and the sensing coil 2 form a sensing communication circuit, and the entire sensing communication circuit is encapsulated within the packaging layer 3. The capacitive pressure sensor 1 is used to convert a pressure signal into an electrical signal through a change in capacitance.

[0035] The sensing coil 2 is a nano silver coil formed by a random network using a hybrid nanostructure based on AgNFs and AgWFs. This coil has a relatively large communication area, high transparency, stretchability, fine geometry, and low sheet resistance, and is used to complete the wireless measurement of eyelid pressure with an external measurement circuit placed on glasses at a certain wireless frequency.

[0036] As Figure 4 shown, the capacitive pressure sensor 1 includes a base layer 11, a capacitive electrode layer 12, and an intermediate pressure sensing layer 13. Two capacitive electrode layers 12 form a capacitor, and the capacitor is connected to the sensing coil 2.

[0037] The capacitive electrode layer 12 is made of rGO material, which is highly transparent with a light transmittance of over 60% and has the advantage of low haze. Compared with contact lenses made of other materials, the contact lens with the capacitive electrode layer 12 made of rGO material can cover the entire pupil range, and the resulting area advantage can extremely improve the pressure detection sensitivity and achieve highly sensitive and stable measurement of eyelid pressure.

[0038] The intermediate pressure sensing layer 13 is located between the two capacitive electrode layers 12 and is made of Ecoflex 0030 material. When pressure is applied, the thickness of the intermediate pressure sensing layer 13 changes with the magnitude of the applied pressure. When the thickness of the intermediate pressure sensing layer 13, i.e., the dielectric thickness, changes, the distance between the capacitive electrode layers 12 also changes, thereby changing the capacitance of the entire capacitive pressure sensor 1. The relationship between the capacitance and the dielectric thickness is:

[0039]

[0040] where C represents the capacitance value; εr represents the relative permittivity; S represents the area of the capacitive electrodes facing each other; and d represents the distance between the capacitive electrodes, i.e., the dielectric thickness.

[0041] This embodiment will provide a method for manufacturing a contact lens. Its steps can be roughly divided into: manufacturing the capacitive pressure sensor 1, manufacturing the sensing coil 2, and packaging the contact lens.

[0042] Method for preparing the capacitive pressure sensor 1: Synthesize pHEMA as the base layer, soak the synthesized pHEMA in water to absorb water for subsequent work. Modify a layer of rGO film on the base layer 11 by spin coating to prepare a highly transparent and stretchable transparent electrode on the upper layer as one capacitive electrode plate 12 of the capacitive sensor 1. Prepare another capacitive electrode plate 12 in the same way, and the two capacitive electrode plate layers 12 form a capacitor. Finally, spin coat a film of Ecoflex 0030 with an extremely low elastic modulus as the intermediate pressure-sensing layer 13 between the two electrode plates, thereby constructing a pressure-sensing film with high transparency and high sensitivity.

[0043] Method for preparing the sensing coil 2: The main materials of the sensing coil 2 are AgNFs and AgNWs. First, prepare AgNFs by electrospinning technology, continuously electrospin silver nanoparticles dissolved in ethylene glycol onto the target substrate. Subsequently, heat anneal the electrospinning at 150 °C for 30 min to make the electrospun silver nanoparticles aggregate and conduct electricity. Then, place it in the AgNWs suspension and electrospray it onto the electrospun AgNFs sample to fill the gaps between AgNFs to maintain a low resistance in the fine wireless mode, thereby realizing a reliable signal transmission function inside the contact lens. In this way, the preparation of the silver nanogrid is completed. Through reactive ion etching, etch the prepared silver nanogrid into a coil pattern. That is, first print the pattern, then prepare a protective film through an exposure technique and hot emboss it onto the silver nanogrid, and then prepare a silver nanocoil through reactive etching. Finally, wash off the protective film with a release agent to complete the preparation of the sensing coil 2. After the preparation is completed, use the sacrificial film transfer method to complete the demolding and transfer of the sensing coil 2 made of silver nanomaterials.

[0044] Encapsulate the contact lens: Connect the sensing coil 2 and the two capacitive electrode plate layers 12 through silver paste to complete the entire sensing communication circuit, and then place the prepared material on the PVA hydrogel film prepared by the freeze-thaw method for fixation, and then spin coat an insulating silicone gel as the encapsulation layer 3 on the surface. After heating and dissolving the PVA gel film, encapsulate the other side of the device in the opposite direction to complete the encapsulation process of the device.

[0045] Due to the use of various highly transparent materials such as graphene and silver nanomaterials in the prepared contact lens, its light transmittance can reach more than 60%, and it has the advantage of low haze. Since the transparency of this sensor is higher and it can cover the entire pupil range, the area advantage brought by this can extremely improve the pressure detection sensitivity and achieve highly sensitive and stable measurement of eyelid pressure.

[0046] Such as Figure 5As shown, the external energy supply receiving device transfers energy through the principle of electromagnetic induction, transferring the energy on the transmitting coil to the sensing coil in the contact lens. The alternating current in the AC power supply is converted into direct current after rectification and filtering to provide energy for the sensing and communication circuit. The sensing and communication circuit that obtains electrical energy forms an LC oscillation circuit.

[0047] As Figure 6 shown, the sensing and communication circuit continuously transmits periodic energy signals to the receiving coil through the coupling between inductors. In the LC oscillation circuit, the current changes periodically, and this period conforms to the following law:

[0048] ,

[0049] where T represents the current period, f represents the current frequency, π represents pi, L represents the sensor inductance, and C represents the capacitance.

[0050] Next, the signal acquisition and analysis case of the present utility model will be described in conjunction with the attached Figure 7 drawings:

[0051] The transmitting coil transmits the direct current after rectification and filtering to the sensing and communication circuit. After the sensing and communication circuit obtains electrical energy, it forms an LC oscillation circuit. Then, the sensing and communication circuit continuously transmits electrical energy signals to the receiving coil at a certain period.

[0052] After the subject wears the contact lens, the eyelid of the subject gives a pressure to the contact lens. This pressure causes the thickness of the intermediate pressure sensing layer 13 of the capacitive pressure sensor 1 in the contact lens to change. This change causes the dielectric thickness of the capacitor formed by the two capacitor plate layers 12 to change, and finally changes the capacitance.

[0053] After the capacitance changes, the original current period is broken, and the sensing and communication circuit transmits the changed electrical energy signal to the receiving coil.

[0054] At this time, the vector network analyzer connected to the external energy supply receiving device simultaneously receives the input signal on the transmitting coil and the output signal on the receiving coil. The vector network analyzer can measure the S11 parameter, that is, the input reflection coefficient, on the transmitting coil and the S12 parameter, that is, the reflection transmission coefficient, on the receiving coil through these two signals. The S11 parameter reflects the relationship between the reflected signal and the input signal and represents the energy loss in the system.

[0055] In a vector network analyzer, a curve relationship diagram of frequency and S11 parameter and S12 parameter can be plotted. In the frequency - S11 parameter diagram, when at the resonance frequency, the S11 parameter is the smallest and the energy loss is the least. In the frequency - S12 parameter diagram, when at the resonance frequency, the S12 parameter is the largest and the energy transmission efficiency is the highest. By combining the two diagrams, a frequency point with both a relatively large energy transmission efficiency and a relatively large reflection signal can be found. When the parameters on the receiving coil change, especially when the capacitive sensor changes, the frequency point with the largest reflection signal will shift. By analyzing this frequency shift, we can accurately calculate the change in capacitance on the receiving coil. The relationship between the frequency shift and the change in capacitance is as follows:

[0056]

[0057] Among them, Δf represents the change value of the current frequency; π represents the pi; L represents the sensor inductance; C represents the capacitance, and ΔC represents the change in capacitance.

[0058] Finally, by constructing a relationship formula between the change in capacitance and the eyelid pressure, the eyelid pressure value of the subject can be measured.

Claims

1. A contact lens type eyelid pressure measurement system, characterized in that, Comprising: A contact lens, the structure of which includes a capacitive pressure sensor, a sensing coil and a packaging layer. The contact lens is worn between the eyeball and eyelid of a subject for acquiring an eyelid pressure signal and converting it into an electrical energy signal; An external energy supply receiving device, wirelessly connected to the contact lens, for supplying energy to the contact lens and receiving the electrical energy signal sent by the contact lens; A signal analysis device, which is used for analyzing the received electrical energy signal to obtain the pressure value of the subject's eyelid; The capacitive pressure sensor includes: A base layer, with a total of two layers, upper and lower; A capacitive electrode layer, with a total of two layers, respectively arranged on one side of the upper and lower base layers; An intermediate pressure sensing layer, arranged between the two capacitive electrode layers. When under pressure, the thickness of the intermediate pressure sensing layer changes with the magnitude of the applied pressure; The sensing coil is a nano-silver coil formed by using a random network of a hybrid nanostructure based on AgNFs and AgWFs. The sensing coil is connected to the capacitive electrode layer to form a sensing communication circuit.

2. The corneal contact lens type eyelid pressure measurement system according to claim 1, wherein: The signal analysis device includes a vector network analyzer.

3. The corneal contact lens type eyelid pressure measurement system according to claim 1, wherein: The capacitive pressure sensor has high transparency and strong light transmittance, and its surface can cover the entire pupil range of the subject.

4. The corneal contact lens type eyelid pressure measurement system according to claim 1, wherein: The intermediate pressure sensing layer uses an Ecoflex 0030 film with a low elastic modulus.

5. The corneal contact lens type eyelid pressure measurement system according to claim 1, characterized in that: The material used for the capacitive electrode layer is highly transparent reduced graphene oxide.

6. The corneal contact lens type eyelid pressure measurement system according to claim 1, wherein: The base layer uses pHEMA material, and the packaging layer uses a silicone gel with properties similar to pHEMA.

7. The corneal contact lens type eyelid pressure measurement system according to claim 1, wherein: The main body of the nano-silver coil is an electrospun fiber prepared from AgNFs, and the AgNWs material is used to fill the gaps between the networks formed by the electrospun fibers.

8. The corneal contact lens type eyelid pressure measurement system according to claim 1, characterized in that: The external energy supply receiving device is provided with a transmitting coil and a receiving coil.

9. The corneal contact lens type eyelid pressure measurement system according to claim 1 or 8, characterized in that: The external energy supply receiving device conducts energy transmission through the principle of electromagnetic induction, transmitting the energy on the transmitting coil to the sensing coil inside the contact lens. The alternating current in the coil is converted into direct current after rectification and filtering to provide electrical energy for the sensing communication circuit.

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