ICP and ICT monitor based on optical MEMS

Abstract

The application discloses an intracranial pressure (ICP) and intracranial temperature (ICT) monitor based on optical MEMS, comprising: a broadband light source and a tunable optical filter (TOF), an optical standard instrument, a plurality of optical receivers, a plurality of optical couplers, a probe; wherein the probe comprises an intracranial pressure (ICP) sensor and an intracranial temperature (ICT) sensor; the ICP is obtained through the trough wavelength value of the reflection spectrum of the ICP sensor, and the trough wavelength value is obtained by comparing the periodic spectrum with the optical standard instrument having an absolute wavelength marker; the ICT is obtained through the peak wavelength value of the reflection spectrum of the ICT sensor, and the peak wavelength value is obtained by comparing the periodic spectrum with the optical standard instrument having an absolute wavelength marker. The application can accurately monitor ICP and ICT.

Description

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 113883, filed November 15, 2020, and U.S. Provisional Patent Application No. 63 / 113882, filed November 15, 2020. The entire contents of those applications are incorporated herein by reference. Technical Field

[0002] This application relates to the field of neurosurgery, and more particularly to an optical MEMS-based intracranial pressure (ICP) and intracranial temperature (ICT) monitor. Background Technology

[0003] Intracranial space contains brain tissue, cerebrospinal fluid, and blood. These three materials maintain the stability of intracranial pressure (ICP). All three are incompressible. High intracranial pressure, if not addressed promptly, can cause permanent brain tissue deformation and lead to death. Invasive ICP monitoring is the gold standard in medicine.

[0004] The earliest invasive ICP monitor in history consisted of a 1.5-meter-long tube connected to a bubble. The bubble, placed inside the skull, sensed the ICP and transmitted pressure signals through the tube. On the other side of the tube, a pressure sensor monitored the pressure. However, the bubble was too large and inconvenient to operate.

[0005] Later, piezoelectric ICP monitors and piezoresistive ICP monitors were invented. These two types of electrical-based MEMS ICP monitors are susceptible to electromagnetic interference. Under computed tomography (CT) or magnetic resonance imaging (MRI), the probe produces unexpected erroneous images. More seriously, the powerful electromagnetic waves generated by MRI can move the probe in the head, damaging it. To avoid these problems, the implanted probe must be removed from the patient's head before an MRI scan, which is extremely inconvenient.

[0006] In recent years, ICP monitoring instruments have been developed based on optical MEMS. Light is guided by optical fiber and shines onto the film of the ICP sensor. ICP changes the shape of the film, thus altering the power of the light reflected from the film. By monitoring the light power, the system can determine the ICP. This ICP monitoring instrument is unaffected by electromagnetic waves. However, the optical fiber may occasionally bend unexpectedly, changing the light power and thus interfering with the ICP being monitored.

[0007] To date, all ICT sensors are based on electrical thermistors. Therefore, there is an urgent need to develop a new type of optical MEMS-based ICP and ICT monitoring instrument that does not require electricity and does not rely on light energy, thus ensuring that ICP and ICT monitoring is not affected by electromagnetic waves or fiber optic bending. Summary of the Invention

[0008] This application provides an ICP and ICT monitoring instrument based on optical MEMS to solve the problem that the monitoring of ICP and ICT in the prior art is affected by electromagnetic waves or fiber bending.

[0009] The embodiments of this application provide an optical MEMS-based ICP and ICT monitoring instrument, including:

[0010] Broadband light source and tunable filter (TOF), optical etalon, multiple optical receivers, multiple optical couplers, probe;

[0011] The probes include an ICP sensor and an ICT sensor; the ICP is obtained by comparing the trough wavelength value of the reflection spectrum of the ICP sensor with its periodic spectrum using an optical etalon with an absolute wavelength marking.

[0012] The ICT is obtained by comparing the peak wavelength value of the reflection spectrum of the ICT sensor with its periodic spectrum using an optical etalon with an absolute wavelength marking.

[0013] In the aforementioned optical MEMS-based ICP and ICT monitoring instruments of this application, an optical etalon with an absolute wavelength marker is used to generate a periodic spectrum as a scale to measure the absolute trough wavelength value or peak wavelength value in the reflection spectrum of the ICP sensor or the ICT sensor.

[0014] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICP sensor and the ICT sensor are integrated in a probe and are respectively connected to their respective single-mode optical fibers, forming a parallel structure between the two optical fibers and the connected sensors.

[0015] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICP sensor and the ICT sensor are integrated into a probe and connected by a single-mode optical fiber. The single-mode optical fiber and the two sensors connected to it form a series structure.

[0016] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICP sensor is a MEMS resonant cavity structure, composed of a single-mode optical fiber, a MEMS film, and a glass substrate, and the end face of the single-mode optical fiber serves as a reflector; the MEMS film is slightly deformed due to ICP; and the trough wavelength value of the reflection spectrum of the ICP sensor is used to monitor ICP.

[0017] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICP sensor is a MEMS resonant cavity structure, composed of a single-mode lens fiber, a MEMS film, and a glass substrate, and the end face of the single-mode lens fiber serves as a reflector; the MEMS film is slightly deformed due to ICP; and the trough wavelength value of the reflection spectrum of the ICP sensor is used to monitor ICP.

[0018] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICP sensor is a MEMS resonant cavity structure, consisting of a single-mode fiber collimator, a MEMS film, and a glass substrate, with the lens plane of the single-mode fiber collimator serving as a reflector; the MEMS film is slightly deformed due to ICP; and the trough wavelength value of the reflection spectrum of the ICP sensor is used to monitor ICP.

[0019] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICT sensor is a fiber Bragg grating; the peak wavelength value of the reflection spectrum of the ICT sensor is used to monitor ICT.

[0020] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICT sensor is a MEMS resonant cavity structure, composed of a single-mode optical fiber, a MEMS film, and a glass substrate, and the end face of the single-mode optical fiber serves as a reflector; the MEMS film is slightly deformed due to ICP; the trough wavelength value of the reflection spectrum is used to monitor ICT.

[0021] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the ICT sensor is a resonant cavity structure, consisting of a single-mode optical fiber, a second reflector, and a glass substrate, with the end face of the single-mode optical fiber serving as the reflector; the cavity length of the resonant cavity structure varies with the ICT; and the trough wavelength value of the reflection spectrum is used to monitor the ICT.

[0022] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the optical coupler is used to connect all optical components and sensors.

[0023] In the aforementioned optical MEMS-based ICP and ICT monitoring instruments of this application, the optical coupler can be replaced by an optical circulator.

[0024] In the aforementioned optical MEMS-based ICP and ICT monitoring instrument of this application, the combination of the broadband light source and the TOF can be replaced by a tunable laser source.

[0025] According to the optical MEMS-based ICP and ICT monitoring instrument of this application, the broadband light source travels along a single-mode optical fiber to a Time-of-Flight (TOF) sensor and is scanned. The scanned broadband light source is then split into two optical paths. One path leads to an optical MEMS sensor to obtain the trough or peak wavelength values ​​of the transmission, reflection, or interference spectra. The other path leads to an optical etalon to obtain a periodic spectrum with absolute wavelength markings, serving as a scale. By comparing with the scale, the trough or peak wavelength values ​​can be accurately measured, thereby obtaining the parameter to be monitored. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an ICP and ICT monitoring instrument based on optical MEMS provided in one embodiment of this application.

[0027] Figure 2 This is a cross-sectional view of an FBG-based probe integrated with an ICP sensor and an ICT sensor, provided in one embodiment of this application. Figure 3 This is a cross-sectional view of an ICP sensor with a MEMS film and a single-mode optical fiber provided in an embodiment of this application, with its end face serving as a reflector for the MEMS resonant cavity.

[0028] Figure 4 This is a cross-sectional view of an ICT sensor composed of a fiber Bragg grating provided in an embodiment of this application.

[0029] Figure 5A and Figure 5B The reflectance spectra of an ICP sensor and an ICT sensor provided in one embodiment of this application are shown. The reference numerals in the specifications are as follows:

[0030] 1. Broadband light source; 2. Tunable filter (TOF); 3. Optical etalon; 4. Optical receiver; 5. Optical coupler;

[0031] 6. Probe; 61. Intracranial pressure (ICP) sensor; 62. Intracranial temperature (ICT) sensor; 611. Single-mode optical fiber; 6111. Optical fiber end face; 612. MEMS membrane; 613. Glass tube. Detailed Implementation

[0032] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0033] In one embodiment, such as Figure 1 The diagram shown is a structural schematic of an ICP and ICT monitoring instrument based on optical MEMS according to an embodiment of the present invention, including:

[0034] Broadband light source 1 and tunable filter 2 (TOF 2), optical etalon 3, multiple optical receivers 4, multiple optical couplers 5, probe 6;

[0035] The probe 6 includes an intracranial pressure (ICP) sensor 61 and an intracranial temperature (ICT) sensor 62;

[0036] ICP is obtained by comparing the trough wavelength value of the reflection spectrum of the ICP sensor 61 with the periodic spectrum using an optical etalon 3 with an absolute wavelength marking.

[0037] The ICT is obtained by comparing the peak wavelength value of the reflection spectrum of the ICT sensor 62 with the periodic spectrum using an optical etalon 3 with an absolute wavelength marking.

[0038] The optical etalon 3 is used to generate a periodic spectrum as a scale to measure the absolute trough wavelength or peak wavelength in the reflection spectrum of the ICP sensor 61 or the ICT sensor 62.

[0039] Specifically, a broadband light source passes through a single-mode fiber 611 and is scanned by a TOF2 sensor. The scanned light is then split into two optical paths by an optical coupler 5. One of the broadband beams, scanned by the TOF2 sensor, illuminates the ICP sensor 61 and the ICT sensor 62, and is reflected back to two optical receivers 4 via multiple optical couplers 5. The trough or peak wavelength values ​​of the two reflected spectra of the ICP sensor 61 and the ICT sensor 62 can be obtained. The other broadband beam, scanned by the optical coupler 5, illuminates an optical etalon 3 and is reflected back to the optical receiver 4 via multiple optical couplers 5, thus receiving a periodic spectrum with absolute wavelength markings as a scale. By comparing the trough or peak wavelength values ​​with the scale, the system can determine the wavelength, thereby obtaining the parameter to be monitored.

[0040] In one embodiment, the ICP sensor 61 is a MEMS resonant cavity structure, consisting of a single-mode fiber 611, a MEMS film 612, and a glass tube 613; the end face 6111 of the single-mode fiber 611 serves as a reflector; the MEMS film 612 is slightly deformed due to ICP; the trough wavelength value of the reflection spectrum of the ICP sensor 61 is used to monitor ICP; the ICT sensor 62 is a fiber Bragg grating; the peak wavelength value of the reflection spectrum of the ICT sensor 62 is used to monitor ICT.

[0041] like Figure 2The diagram shows a cross-sectional view of probe 6, which integrates an FBG-based ICP sensor 61 and an ICT sensor 62. The ICP sensor 61 is a MEMS resonant cavity structure, composed of the end face 6111 of a single-mode fiber 611, a MEMS film, and a glass tube 613. The MEMS film 612 deforms with changes in ICP, thus changing the trough wavelength values ​​of the reflection spectrum of the ICP sensor 61. The ICT sensor 62 is constructed from a fiber Bragg grating. The peak wavelength values ​​of the reflection spectrum of the ICT sensor 62 change with ICT, indicating the parameters of ICT.

[0042] Similarly, the ICT sensor 62 is a MEMS resonant cavity structure, consisting of a single-mode fiber 611, a MEMS film 612, and a glass tube 613. The end face 6111 of the single-mode fiber 611 serves as a reflector. The MEMS film 612 is slightly deformed due to ICT. The trough wavelength value of the reflection spectrum is used to monitor ICT.

[0043] The ICT sensor 62 has the same structure as the ICP sensor 61, wherein the length of its resonant cavity varies with temperature.

[0044] The ICT sensor 62 can also be made of a fiber Bragg grating, wherein the peak wavelength of the reflection spectrum of the fiber Bragg grating varies with the ICT. By monitoring the light wavelength, the system can determine the ICT.

[0045] In another embodiment, such as Figure 3 The diagram shows a cross-sectional view of an ICP sensor 61, which includes a MEMS membrane 612 and a single-mode optical fiber 611, with its end face 6111 serving as a mirror for the MEMS resonant cavity. A glass tube 613 supports all components. ICP causes a slight deformation of the MEMS membrane 612, thereby changing the trough wavelength values ​​in the reflection spectrum. By measuring the wavelength, the pressure can be determined.

[0046] In another embodiment, such as Figure 4 The image shows a cross-sectional view of an ICT sensor 62 with a fiber Bragg grating within a single-mode fiber 611. The ICT sensor 62 is a fiber Bragg grating with a peak shape in the reflection spectrum. When the ICT changes, the peak wavelength value changes. The ICT can be obtained by measuring the wavelength.

[0047] In one embodiment, such as Figure 5A and Figure 5B The image shows the shape of the reflection spectrum of ICP sensor 61 and ICT sensor 62. The trough wavelength values ​​in the reflection spectrum of ICP sensor 61 are shown below. Figure 5A As shown. By calculating the trough wavelength values, the system can obtain the ICP to be monitored. The peak wavelength values ​​of the reflection spectrum of ICT sensor 62 are shown in the figure. Figure 5BAs shown. By calculating the peak wavelength value, the system can obtain the ICT to be monitored.

[0048] In one embodiment, an electronic temperature sensor may be used to address the thermal effects of the TOF2, optical etalon 3, and fiber Bragg grating.

[0049] In one embodiment, the ICP and ICT monitor and the optical coupler 5 connected to the probe can be replaced by an optical circulator.

[0050] In one embodiment, the combination of broadband light source 1 and TOF2 can be replaced by a tunable laser source.

[0051] In other embodiments, the optical MEMS-based ICP and ICT monitor provided in this application can be used to monitor a set of vital signs, such as heart rate and respiratory rate. Since heartbeat or breathing causes changes in ICP and ICT, heart rate, respiratory rate, etc., can be obtained by analyzing ICP and ICT.

[0052] The optical MEMS-based ICP and ICT monitoring instrument and its probe 6 provided in this application have been upgraded. The probe 6 is integrated with an optical MEMS-based ICP sensor 61 and a fiber Bragg grating-based ICT sensor 62. All optical components and optical sensors are connected to a single-mode fiber 611. The trough or peak wavelength values ​​of the sensor's transmission, reflection, or interference spectra are functions of the ICP or ICT parameters to be monitored. The wavelength is obtained by comparing it with a comb-shaped periodic spectrum using an optical etalon 3 with absolute wavelength markings. Once the trough or peak wavelength values ​​are determined, the parameters to be monitored are obtained.

[0053] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An ICP and ICT monitoring instrument based on optical MEMS, characterized in that, include: Broadband light source and tunable filter TOF, optical etalon, multiple optical receivers, multiple optical couplers, probe; The probes include an intracranial pressure (ICP) sensor and an intracranial temperature (ICT) sensor. ICP is obtained by comparing the valley wavelength of the reflection spectrum of the ICP sensor with the periodic spectrum using an optical etalon with an absolute wavelength marking. The ICT is obtained by comparing the peak wavelength of the reflection spectrum of the ICT sensor with the periodic spectrum using an optical etalon with an absolute wavelength marking. The ICP sensor and the ICT sensor are integrated into a single probe and connected in parallel with two single-mode optical fibers; The ICP sensor is a MEMS resonator structure, consisting of a single-mode optical fiber, a MEMS film, and a glass substrate, with the tip of the single-mode optical fiber serving as a reflector. The MEMS film is slightly deformed due to ICP; the valley wavelength of the reflection spectrum of the ICP sensor is used to monitor ICP; Alternatively, the ICP sensor is a MEMS resonator structure, consisting of a single-mode fiber collimator, a MEMS film, and a glass substrate, with the lens plane of the single-mode fiber collimator serving as a reflector. The MEMS film is slightly deformed due to ICP; the valley wavelength of the reflection spectrum of the ICP sensor is used to monitor ICP; The ICT sensor is a MEMS resonator structure, consisting of a single-mode optical fiber, a MEMS film, and a glass substrate, with the tip of the single-mode optical fiber serving as a reflector. The MEMS film was slightly deformed due to ICT; The peak wavelength of the reflectance spectrum is used to monitor ICT; Alternatively, the ICT sensor is a resonator structure consisting of a single-mode fiber, a second reflector, and a glass substrate, with the tip of the single-mode fiber serving as the reflector; the cavity length of the resonator structure varies with the ICT; and the peak wavelength of the reflection spectrum is used to monitor the ICT.

2. The ICP and ICT monitoring instrument based on optical MEMS according to claim 1, characterized in that, The optical etalon with absolute wavelength markings is used to generate periodic spectra as a scale to measure the absolute peak or valley wavelengths in the reflection spectrum of the ICP sensor or the ICT sensor.

3. The ICP and ICT monitoring instrument based on optical MEMS according to claim 1, characterized in that, The ICT sensor is a fiber Bragg grating; the peak wavelength of the reflection spectrum of the ICT sensor is used to monitor ICT.

4. The ICP and ICT monitoring instrument based on optical MEMS according to claim 1, characterized in that, The optical coupler is used to connect all optical components and sensors.

5. The ICP and ICT monitoring instrument based on optical MEMS according to claim 1, characterized in that, The optical coupler can be replaced by an optical circulator.

6. The ICP and ICT monitoring instrument based on optical MEMS according to claim 1, characterized in that, The combination of the broadband light source and the TOF can be replaced by a tunable laser source.

7. The ICP and ICT monitoring instrument based on optical MEMS according to claim 1, characterized in that, The optical MEMS-based ICP and ICT monitor is used to analyze ICP and ICT and can obtain a set of vital signs, which include at least heart rate and respiratory rate.

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