KR102312209B1 - Intraocular pressure measurement apparatus using acoustic radiation force - Google Patents

Abstract

The present invention relates to a device for measuring intraocular pressure using ultrasonic acoustic radiation force. According to the present invention, in the apparatus for measuring intraocular pressure using ultrasonic acoustic radiation force, an ultrasonic wave comprising a plurality of piezoelectric elements arranged in an array form and transmitting an ultrasonic signal generated by the plurality of piezoelectric elements to the eyeball and then receiving a reflected signal A transducer, a signal generator for applying an input signal for adjusting the phase of the plurality of piezoelectric elements to each of the plurality of piezoelectric elements, and a signal processor for measuring the elasticity of the eyeball surface by analyzing the received ultrasonic signal received by the ultrasonic transducer It provides an intraocular pressure measurement device comprising a.
According to the present invention, by using ultrasound as an energy source, not only elastic information for accurate intraocular pressure measurement in real time can be obtained, but also an eyeball image can be obtained.

Description

Intraocular pressure measurement apparatus using acoustic radiation force

The present invention relates to a device for measuring intraocular pressure using ultrasonic acoustic radiation force, and more particularly, to measure the intraocular pressure by measuring the elasticity of the eyeball using ultrasonic acoustic radiation force to accurately predict the time of glaucoma treatment. It's about the device.

Measurement of intraocular pressure is one of the most basic tests performed for patients with eye diseases. Recently, as the number of patients with glaucoma, in which the optic nerve is damaged due to abnormally high intraocular pressure, is rapidly increasing, the demand for a tonometer that can efficiently measure intraocular pressure is greatly increasing.

Accurate measurement of intraocular pressure plays a very important role in glaucoma risk screening, efficient diagnosis and treatment of patients undergoing glaucoma, and monitoring the progress after treatment.

The methods for measuring intraocular pressure currently used are largely divided into contact and non-contact methods.

The contact type can be classified into intrusion and applanation tonometer. The intrusion tonometer is a device that measures the dent of the cornea when a certain weight is placed on the cornea and measures the intraocular pressure. It is a method of measuring intraocular pressure by measuring the force required to flatten it. However, in this case, it takes a lot of time, requires anesthesia of the cornea using an eye drop anesthetic, and it is a bench type that needs to be instilled with a fluorescent dye and observed under a microscope. There is a limitation that this is not easy.

Another contact-type tonometer to overcome this limitation is a device that measures intraocular pressure based on the principle of trigger and collision. This equipment has the advantage of fast measurement time and easy portability, but since the probe has to collide with the cornea, it causes tension in the patient and pain during the collision.

Unlike these contact methods, non-contact tonometers measure intraocular pressure by releasing compressed air and changing the surface reflection of the cornea. Because it is irradiated, the patient is easily nervous and uncomfortable, and above all, there is a problem in that the accuracy is lower than that of the contact type.

As mentioned above, the existing intraocular pressure measuring device measures the intraocular pressure in a non-contact manner using light and compressed air or by physically contacting the eye with a probe without closing the eyes, causing great inconvenience such as pain and tension to the patient. The development of intraocular pressure measurement technology using a new energy source is required because there are many cases where it results in a high blood pressure or the accuracy is low.

Moreover, the number of patients suffering from glaucoma is increasing recently, and the need for a fast, convenient and highly accurate intraocular pressure measurement device is increasing. In addition, there is a growing need for medical devices that are not limited to use in hospitals, but can be easily and conveniently used at home. Accordingly, there is a need for a new intraocular pressure measurement technology capable of increasing accuracy in measuring intraocular pressure while minimizing patient discomfort.

The technology that is the background of the present invention is disclosed in Korean Patent Application Laid-Open No. 2019-0074637 (2019.06.28).

An object of the present invention is to provide a device for measuring intraocular pressure using ultrasonic acoustic radiation force, which can accurately measure intraocular pressure through eye elastic information obtained using ultrasonic acoustic radiation force.

The present invention relates to an intraocular pressure measuring apparatus using ultrasonic acoustic radiation force, an ultrasonic transducer including a plurality of piezoelectric elements arranged in an array form and transmitting an ultrasonic signal generated by the plurality of piezoelectric elements to the eyeball and then receiving a reflected signal and a signal generator for applying an input signal for adjusting the phase of the plurality of piezoelectric elements to each of the plurality of piezoelectric elements, and a signal processor for measuring the elasticity of the eyeball surface by analyzing the ultrasonic reception signal received by the ultrasonic transducer. It provides an intraocular pressure measurement device comprising.

In addition, the plurality of piezoelectric elements receives input signals of the same phase from the signal generator, respectively, and the ultrasonic transducer receives a single-focal point from the plurality of piezoelectric elements in response to input signals of the same phase. ) can generate ultrasound.

In addition, the plurality of piezoelectric elements receives an input signal of any one of the first and second phases different from each other from the signal generator, and the ultrasonic transducer is a mixed phase in which the first and second phases are mixed. Multi-focal point ultrasonic waves may be generated from the plurality of piezoelectric elements in response to an input signal.

In addition, the plurality of piezoelectric elements are divided into first and second groups according to an arrangement position, and the signal generator applies an input signal of a first phase to the piezoelectric elements of the first group, respectively, and the first phase Inverted second phase input signals may be respectively applied to the piezoelectric elements of the second group.

The plurality of piezoelectric elements may be alternately arranged such that the piezoelectric elements of the first group and the piezoelectric elements of the second group are adjacent to each other.

In addition, each of the plurality of piezoelectric elements has a structure in which two piezoelectric elements having opposite polarization directions are bonded back and forth according to the traveling direction of an ultrasonic signal, and the ultrasonic transducer is configured to generate multiple frequency components from the plurality of piezoelectric elements. It can generate ultrasonic waves with

In addition, the piezoelectric element may be implemented as a bulk type using a single material or a composite type using a composite material.

In addition, the ultrasonic transducer may have a concave lens on one surface.

In addition, the ultrasonic transducer transmits and receives an ultrasonic signal in a contact or non-contact state on the eyelid surface when the subject's eyes are closed, and transmits and receives an ultrasonic signal in a non-contact state in front of the eyeball when the eye is open. have.

Also, the signal processor may output a level of intraocular pressure corresponding to the elasticity of the eyeball surface or whether the intraocular pressure is normal.

In addition, the signal processor may measure the movement amount of the eyeball surface from the ultrasonic reception signal, and calculate an elastic modulus of the eyeball surface corresponding to the movement amount of the eyeball surface.

In addition, the signal generator includes a first driving mode for applying a reference signal serving as a starting point for measuring the amount of movement of the medium, a second driving mode for applying a pushing signal for shaking the medium, and A third driving mode for applying a detection signal having the same signal type as that of the first driving mode may be sequentially driven immediately after the pushing signal is applied.

In addition, the signal processor compares the first ultrasonic received signal obtained when the reference signal is applied with the second ultrasonic received signal obtained when the detection signal is applied, and measures the movement amount of the eyeball surface and corresponds to the movement amount elasticity can be calculated.

In addition, the first and third driving modes are in-phase modes in which input signals of the same phase are applied to the plurality of piezoelectric elements, and the second driving mode is a second input signal having a first phase and an inverted phase thereof. It may be a mixed phase mode in which phase input signals are applied to the piezoelectric elements of the first group and the piezoelectric elements of the second group, respectively.

Also, all of the first to third driving modes may be in-phase modes in which input signals of the same phase are applied to the plurality of piezoelectric elements.

According to the present invention, by using ultrasound as an energy source, not only elastic information for accurate intraocular pressure measurement in real time can be obtained, but also an eyeball image can be obtained.

In addition, according to the present invention, since the intraocular pressure can be measured by contacting or non-contacting the ultrasound probe on the eyelid in the state in which the patient's eyes are closed as well as in the state with the eyes open, unlike the conventional method for measuring intraocular pressure, pain or discomfort felt by the patient It relieves discomfort and can measure intraocular pressure conveniently without tension.

1 is a diagram showing the configuration of an intraocular pressure measuring apparatus using ultrasonic acoustic radiation force according to an embodiment of the present invention.
2 is a view for explaining the same-phase mode and the mixed-phase mode applied to the ultrasonic transducer according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating ultrasound signals of single focal points and multiple focal points respectively generated according to the same phase mode and the mixed phase mode shown in FIG. 2 .
4 is a view for explaining the form of a signal applied to an ultrasonic transducer to obtain elastic information in an embodiment of the present invention.
5 is a view for explaining the concept of a case in which a polarization reversal technique is applied to a piezoelectric element.
6 is a view showing the FEA simulation results for the polarization reversal technique.
FIG. 7 is a diagram illustrating a case in which a polarization reversal technique is applied to each piezoelectric element in the ultrasonic transducer of FIG. 1 .
8 shows the concept of a pulse compression technique according to an embodiment of the present invention.

Then, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them.

1 is a diagram showing the configuration of an intraocular pressure measuring apparatus using ultrasonic acoustic radiation force according to an embodiment of the present invention.

As shown in FIG. 1 , the intraocular pressure measuring apparatus 100 according to an embodiment of the present invention includes an ultrasound transducer 110 , a signal generator 120 , and a signal processor 130 .

The ultrasonic transducer 110 (ultrasonic transducer) is configured to include a plurality of piezoelectric elements 111 arranged in an array form and a housing for embedding them. In the case of FIG. 1, it is exemplified that four piezoelectric elements divided in a 2×2 form are included. Here, the piezoelectric element may be implemented as a bulk type using a single material or a composite type using a composite material. In addition, the plurality of piezoelectric elements 111 can be easily obtained through dividing and processing a single piezoelectric element into a plurality of pieces.

Ultrasonic energy is harmless to the human body and has an advantage that sufficient energy can be transmitted and received inside the eye when the difference in acoustic impedance is appropriate. According to an embodiment of the present invention, elastic information for measuring intraocular pressure can be accurately obtained by using such ultrasound as an energy source.

Since a general ultrasonic transducer uses a single piezoelectric element to transmit and receive ultrasonic waves, the beam is focused on only one place, and there is a problem that the amount of movement of the induced medium is small and non-uniform.

Contrary to this, the ultrasonic transducer used in the present invention has a segmented element shape in which the ultrasonic aperture shape is not a single element as shown in FIG. 1 . According to this structure, unlike using a plurality of ultrasound transducers, ultrasound energy can be collected in a certain area with high precision and one or multiple focal points can be formed in the corresponding area, thereby providing the advantage of enabling precise diagnosis.

Although FIG. 1 describes an element shape divided into four as an example, the embodiment of the present invention is not necessarily limited thereto and may be applied to all ultrasonic transducers having at least two or more divided element types. The cross-sectional shape of the dividing element is not necessarily limited to a rectangular shape.

The signal generator 120 generates an input signal for adjusting the phases of the plurality of piezoelectric elements 111 and applies them to each of the plurality of piezoelectric elements 111 . The signal generator 120 may generate a predetermined input signal according to a control signal (command) sent by the phase adjuster 125 and transmit it to the corresponding piezoelectric element 111 , respectively. The phase adjuster 125 may determine a phase, an application time, and a period of the input signal.

In an embodiment of the present invention, the piezoelectric element may be divided into two groups. The plurality of piezoelectric elements 111 are divided into a first group and a second group according to an arrangement position, and the piezoelectric elements of the first group and the piezoelectric elements of the second group are alternately arranged so as to be adjacent to each other. In the case of FIG. 1, the piezoelectric element of the first group and the piezoelectric element of the second group are adjacent to each other in all directions of up, down, left and right.

Here, the signal generator 120 may generate an ultrasonic wave of a single focal point by applying input signals of the same phase to both groups of piezoelectric elements (first embodiment), By applying the input signal of the phase, it is possible to make the ultrasound of multiple focal points (the second embodiment).

First, describing the first embodiment, input signals of the same phase (eg, first phase) are respectively applied to the plurality of piezoelectric elements 111 in the ultrasonic transducer 110 .

In this case, the ultrasonic transducer 110 generates single-focal point ultrasonic waves from the plurality of piezoelectric elements 111 in response to an input signal of the same phase. Accordingly, a single focal point of ultrasound can be applied to the ocular surface.

Here, the signal generator 120 includes first and second signal generators 120-1 and 120-2 as shown in FIG. 1, and after generating the input signal of the first phase in the first signal generator 120-1, the second The first transmit amplifier 115-1 is amplified and applied to the piezoelectric elements of the first group, and at the same time, the second signal generator 120-2 also generates the input signal of the first phase and then the second transmit amplifier 115 -2) to amplify it and apply it to the piezoelectric element of the second group.

Next, in the case of the second embodiment, an input signal of any one of the different first and second phases generated from the signal generator 120 is applied to the plurality of piezoelectric elements 111 in the ultrasonic transducer 110 .

Specifically, the first phase is applied to the piezoelectric elements of the first group and the second phase (the inverted phase of the first phase) is applied to the piezoelectric elements of the second group, so that as a result, two phases (first phase, second phase) are applied. The input signal of the mixed phase in which the phases are mixed is applied to the ultrasonic transducer 110 .

Accordingly, the ultrasonic transducer 110 generates multi-focal point ultrasonic waves from the plurality of piezoelectric elements 111 in response to the mixed phase input signal. Therefore, in the case of the second embodiment, ultrasound of multiple focal points may be applied to the ocular surface.

Of course, in this case, the first signal generator 120-1 generates the input signal of the first phase, amplifies it through the first transmission amplifier 115-1, applies it to the first group of piezoelectric elements, and at the same time After generating the input signal of the first phase and the inverted second phase through the second signal generator 120-2, amplified through the second transmission amplifier 115-2 and applied to the piezoelectric element of the second group. Accordingly, the first phase and the second phase are alternately input between elements adjacent to each other in the upper and lower and left and right directions.

FIG. 2 is a view for explaining the in-phase mode and the mixed phase mode applied to the ultrasonic transducer according to an embodiment of the present invention, and FIG. 3 is a single focus generated according to the in-phase mode and the mixed phase mode shown in FIG. 2, respectively. It is a diagram showing ultrasound signals of points and multiple focal points.

First, the left figure of FIG. 2 shows four piezoelectric elements included in the ultrasonic transducer, and the right figure shows the same-phase mode and the mixed-phase mode separately according to the phases applied to each piezoelectric element.

The upper right figure illustrates the same-phase mode in which input signals of the same phase are applied to all four piezoelectric elements, which corresponds to the case of the first embodiment.

And the lower right figure shows the mixed phase mode. The input signal of the first phase is applied to the 1st and 4th piezoelectric elements (1st group), while the 2nd and 3rd piezoelectric elements (2nd group) are inverted by 180 degrees. The input signal of the second phase is applied. This corresponds to the case of the second embodiment.

For reference, FIG. 2 illustrates an ultrasonic transducer implemented by dividing a piezoelectric element having a cylindrical structure into quarters. If the cylindrical piezoelectric element is divided into 4 equal parts, an ultrasonic transducer having four piezoelectric elements of the form shown in FIG. 2 can be implemented. Of course, an ultrasonic transducer having N piezoelectric elements may be implemented by dividing a spherical piezoelectric element into N equal parts instead of a cylindrical one.

3 is a simulation result for each mode, showing that in the case of the same phase mode, a single focal point is formed through four piezoelectric elements, whereas in the mixed phase mode, four multiple focal points are formed through four piezoelectric elements. can That is, when signals having the same phase are simultaneously applied to the dividing elements, a single focal point is formed, and when signals mixed with different phases are simultaneously applied to the dividing elements, multiple focal points are formed.

Of course, it can be seen from the results of FIG. 3 that the acoustic radiation power of ultrasound affects a tissue in a wider area compared to a single focal point at multiple focal points.

In the present embodiment, as a technique for measuring intraocular pressure using ultrasonic acoustic radiation force capable of measuring the elastic modulus of the tissue, when the above-described multiple focal points are used, the amount of movement of the tissue (ocular surface) increases during the elastic measurement process. Since it becomes uniform, it becomes possible to acquire high-resolution elastic information. Of course, if the intraocular pressure can be measured with only a small amount of movement, it is also possible to measure the intraocular pressure by forming a single focal point.

The ultrasonic transducer 110 transmits the ultrasonic signal generated by the plurality of piezoelectric elements 111 to the eyeball 10 and then receives the reflected signal. The reflected signal received by the ultrasonic transducer 110 is amplified through the receiving amplifier 135 and then transferred to the signal processor 130 . Here, the reception amplifier 135 may be configured to include two reception amplifiers 135 - 1 and 135 - 2 to correspond to two groups of piezoelectric elements as shown in FIG. 1 .

The signal processor 130 measures the elasticity of the eyeball surface by analyzing the received ultrasound signal. Of course, by analyzing the ultrasonic reception signal, an eyeball image may be acquired and outputted through the display 140 . Acquiring an image from an ultrasound signal corresponds to a known technique, and thus a detailed description thereof will be omitted.

In general, in patients with glaucoma whose intraocular pressure is higher than normal, the elasticity of the ocular surface is observed to be low. Therefore, the lower the elastic modulus of the eyeball, the higher the intraocular pressure.

Elasticity is one of the characteristic values of human tissue, and can be obtained by using the degree of deformation of the tissue measured when the same force is applied. At this time, the force applied per unit area is called stress, the degree of deformation is called strain, and Young's modulus is defined as a ratio value of stress to strain.

The transmitted and received ultrasonic wave itself has an acoustic radiation force that can measure the elastic information of the material. Since elastic information is closely related to pressure, it is possible to measure the elasticity of the eyeball and accurately convert this information into intraocular pressure by efficiently using the acoustic radiation force.

In this way, the signal processor 130 may measure the elasticity of the eyeball surface using the ultrasound signal and obtain the corresponding intraocular pressure from the measured elasticity value. As a simple example, the magnitude of intraocular pressure can be easily converted by multiplying the currently measured elasticity value by a preset conversion factor. The conversion coefficient is a coefficient for converting an elasticity value into an intraocular pressure value, and may be predetermined and standardized through analysis of a relationship between an actual intraocular pressure, which is experimental data obtained for subjects, and a measured elastic modulus.

The signal processor 130 may output not only the level of intraocular pressure corresponding to the elasticity of the eyeball surface, but also whether the intraocular pressure is normal. For example, it is possible to determine whether the intraocular pressure is normal by comparing the converted level of intraocular pressure with an intraocular pressure in a normal range or a corresponding threshold value, and output a determination result.

Here, the signal processor 130 measures the movement amount of the eyeball surface from the ultrasonic reception signal, and calculates an elastic modulus of the eyeball surface corresponding to the movement amount of the eyeball surface. In an embodiment of the present invention, an ultrasound application signal for acquiring elastic information may be configured as follows.

4 is a view for explaining the form of a signal applied to an ultrasonic transducer to obtain elastic information in an embodiment of the present invention.

As shown in FIG. 4, in order to obtain elastic information for the eyeball, the in-phase reference signal (hereinafter, reference signal), the mixed-phase pushing signal (hereinafter, the pushing signal), and the in-phase detection signal (hereinafter, the detection signal) are transmitted to the ultrasonic transducer ( 110) is sequentially applied.

In this regard, the signal generator 120 is a first driving mode for applying a reference signal serving as a starting point for measuring the amount of movement (displacement) of the medium, and applying a pushing signal for shaking the medium. A second driving mode and a third driving mode in which a detection signal having the same signal type as that of the first driving mode is applied are sequentially driven immediately after the pushing signal is applied.

The reference signal is to obtain an image of the ultrasonic reception signal as a reference, in the case of a pushing signal, to induce displacement by applying stress to the ocular surface, and in the case of a detection signal, the tissue during recovery immediately after the application of the pushing signal. This is to detect a change (a movement amount according to time) in an image of an ultrasonic reception signal.

The ultrasonic transducer 110 transmits ultrasonic waves according to the first, second, and third driving modes and receives a reflected signal therefor for each mode. Then, the signal processor 130 compares the second ultrasonic received signal obtained when the detection signal is applied with the first ultrasonic received signal obtained when the reference signal is applied, measures the amount of movement of the ocular surface, and determines the movement amount. The corresponding elasticity can be calculated.

In the case of FIG. 4 , in the case of the first and third driving modes for applying the reference signal and the detection signal, the same phase mode for applying the input signal of the same phase to all the piezoelectric elements is used, and the second driving mode for applying the pushing signal In the case of the driving mode, a mixed phase mode in which input signals of the first phase and the second phase, which is an inverted phase thereof, are individually applied to the piezoelectric elements of the first group and the second group, respectively, is used.

Multiple focal points are formed by the pushing signal of the mixed phase mode, so that a more precise amount of tissue movement can be obtained by the detection signal of the same phase mode. In this case, the frequency, number of cycles, and amplitude of each transmission signal can be adjusted according to a target, and adaptive signal processing technology may be applied for customized diagnosis.

Also, although not shown, unlike in FIG. 4 , the second driving mode may be configured as the same-phase mode instead of the mixed-phase mode. Here, when the analysis result of the ultrasound reception signal obtained by configuring all of the first to third modes as the same phase mode is mixed with the analysis result of the ultrasound reception signal obtained by configuring the second mode as the mixed phase mode as shown in FIG. 4, more precise intraocular pressure measurement may be possible.

FIG. 5 is a diagram for explaining a concept when a polarization reversal technique is applied to a piezoelectric element, and FIG. 6 is a diagram illustrating a finite element analysis (FEA) simulation result for the polarization reversal technique.

As shown in FIG. 5, the polarization inversion technique (inversion layer technique) is a technique using a structure (A) in which two piezoelectric elements 1 and 2 having opposite polarization directions are joined back and forth with respect to the propagation direction of the ultrasonic signal. , using this, multiple frequency components are generated from one piezoelectric element to which the polarization reversal technique is applied and are focused on the tissue surface.

That is, if the polarization reversal technique is applied as in FIG. 5 , multiple frequency components can reach a point in the tissue precisely at the same time. The result of performing FEA simulation to verify the performance of the polarization reversal technique is shown in FIG. 6 .

FIG. 7 is a diagram illustrating a case in which a polarization reversal technique is applied to each piezoelectric element in the ultrasonic transducer of FIG. 1 .

In FIG. 7, each of the plurality of piezoelectric elements 111 in the ultrasonic transducer 110 has a structure in which two piezoelectric elements 111a and 111b having opposite polarization directions are bonded back and forth with respect to the propagation direction of the ultrasonic signal. Able to know.

According to the structure of FIG. 7 , ultrasonic waves having multiple frequency components may be generated from the plurality of piezoelectric elements 111 . That is, in the case of the same phase mode, a single focal point composed of multiple frequency components may be generated, and in the mixed phase mode, multiple focal points each composed of multiple frequency components may be generated.

In this way, if the polarization reversal technique is applied to the divided ultrasonic transducer technique of FIG. can Therefore, it is possible to utilize not only the increased movement amount but also elastic information for each frequency obtained at the same time, individually or in combination, for measuring intraocular pressure.

In addition, the acoustic radiation force is related to the attenuation coefficient and the ultrasonic intensity. As the attenuation increases, the magnitude of the force transmitted to the medium increases, but the intensity of the ultrasonic wave decreases. At this time, since the attenuation is dependent on the frequency and the transmission depth, the optimal frequency may be applied differently depending on the application. Therefore, when ultrasonic waves are transmitted and received using transducers having various frequency bands, an optimized acoustic radiation power can be obtained irrespective of tradeoffs according to frequencies.

As shown in FIGS. 1 and 5 , one surface (surface through which ultrasonic waves are transmitted and received) formed by the piezoelectric elements in the ultrasonic transducer 110 may be processed into a concave shape, thereby increasing the focusing ability of the ultrasonic waves. Of course, the ultrasonic transducer 110 may include a one-sided concave lens in order to improve the surface focusing ability of the piezoelectric elements.

The apparatus for measuring intraocular pressure proposed in the present invention can diagnose both contact and non-contact methods. In particular, the patient can measure both closed and open eyes.

When the eyes are closed, ultrasonic energy is transmitted and received while the ultrasonic transducer is placed on the eyelid surface in a contact or non-contact manner. do. In addition, in the case of the contact method, after removing the eyelid information, eye elasticity information can be obtained. In this way, the intraocular pressure measuring device of the present invention can be selectively operated in a non-contact or contact type depending on the condition of the patient.

An embodiment of the present invention uses a pulse compression technique after transmitting and receiving signals (chirp, Barker, Golay, etc.) coded as a detection signal of the same phase mode in order to maximize the accuracy of eye elasticity information by the ultrasonic acoustic radiation force. This can increase the signal-to-noise ratio.

8 shows the concept of a pulse compression technique according to an embodiment of the present invention. The pulse compression technique is a signal processing technique that transmits a pulse with a long pulse length and low maximum power to achieve the same effect as actually transmitting a short pulse length and high maximum power pulse. When applied to the detection signal (signal for detection in the third driving mode), elastic information having a high signal-to-noise ratio can be obtained.

There are largely chirp, Barker, Golay, and code types of coded excitations showing these characteristics. As such, it is possible to increase the signal-to-noise ratio by applying the pulse compression technique to the detection signal. Since the above-described coded signals correspond to known ones, a detailed description thereof will be omitted.

In addition, in the present invention, it is possible to apply an adaptive signal processing technology that can increase accuracy even in conditions of different eye structures and intraocular pressure for each patient. Adaptive signal processing technology is a technology applied to various fields such as system identification, inverse modeling, prediction, and interference cancellation. say that In other words, the coefficients used in signal processing are different for each patient according to different eye structures, especially curvatures. When transmitting and receiving ultrasound, the characteristics of a received signal appear differently according to different eye curvatures for each patient. By applying an adaptive signal processing technology, an error caused by this can be minimized.

According to the present invention as described above, by using ultrasound as an energy source, not only elastic information for accurate intraocular pressure measurement in real time but also an eyeball image can be obtained.

In addition, according to the present invention, since the intraocular pressure can be measured by contacting or non-contacting the ultrasound probe on the eyelid in the state in which the patient's eyes are closed as well as in the state with the eyes open, unlike the conventional method for measuring intraocular pressure, pain or discomfort felt by the patient It relieves discomfort and can measure intraocular pressure conveniently without tension.

In addition, acoustic radiation power can be enhanced by using an ultrasonic transducer to which split beam technology or polarization reversal technology is applied and a specially designed signal sequence, and efficient elastic information can be obtained based on this. In addition, the pulse compression technique can increase the signal-to-noise ratio, and the adaptive signal processing technique can increase the accuracy even under different eye structures and conditions of intraocular pressure for each patient.

Although the present invention has been described with reference to the embodiment shown in the drawings, which is only exemplary, those of ordinary skill in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

100: tonometry device 110: ultrasound transducer
111: piezoelectric element 115: transmit amplifier
120: signal generator 125: phase adjuster
130: signal processor 135: receive amplifier
140: display

Claims (15)

In the intraocular pressure measuring device using ultrasonic acoustic radiation force,
an ultrasonic transducer including a plurality of piezoelectric elements arranged in an array form and transmitting an ultrasonic signal generated by the plurality of piezoelectric elements to the eyeball and then receiving a reflected signal;
a signal generator for applying an input signal for adjusting the phases of the plurality of piezoelectric elements to each of the plurality of piezoelectric elements; and
It includes a signal processor for measuring the elasticity of the ocular surface by analyzing the received ultrasonic signal received by the ultrasonic transducer,
The plurality of piezoelectric elements,
receiving an input signal of any one of the first and second phases different from each other from the signal generator;
The ultrasonic transducer is
An intraocular pressure measuring apparatus for generating multi-focal point ultrasound from the plurality of piezoelectric elements in response to an input signal of a mixed phase in which the first and second phases are mixed. delete delete The method according to claim 1,
The plurality of piezoelectric elements are divided into first and second groups according to an arrangement position,
The signal generator is
An apparatus for measuring intraocular pressure for respectively applying an input signal of a first phase to the piezoelectric elements of the first group, and respectively applying an input signal of a second phase inverted from the first phase to the piezoelectric elements of the second group. 5. The method according to claim 4,
The plurality of piezoelectric elements,
An intraocular pressure measuring device in which the piezoelectric elements of the first group and the piezoelectric elements of the second group are alternately arranged to be adjacent to each other. The method according to claim 1,
Each of the plurality of piezoelectric elements,
It has a structure in which two piezoelectric elements with opposite polarization directions are bonded back and forth according to the propagation direction of the ultrasonic signal,
The ultrasonic transducer is
An intraocular pressure measuring device for generating ultrasonic waves having multiple frequency components from the plurality of piezoelectric elements. The method according to claim 1,
The piezoelectric element is
An intraocular pressure measuring device implemented in the form of a bulk type using a single material or a composite type using a composite material. The method according to claim 1,
The ultrasonic transducer is
An intraocular pressure measuring device having a concave lens on one surface. The method according to claim 1,
The ultrasonic transducer is
An intraocular pressure measuring device that transmits and receives ultrasound signals in a state of contact or non-contact on the eyelid surface when the subject's eyes are closed, and transmits and receives ultrasound signals in a state of non-contact in front of the eyeball when the subject's eyes are open. The method according to claim 1,
The signal processor is
An intraocular pressure measuring device for outputting a level of intraocular pressure corresponding to the elasticity of the eyeball surface or whether the intraocular pressure is normal. 11. The method of claim 10,
The signal processor is
An intraocular pressure measuring apparatus for measuring a movement amount of the eyeball surface from the ultrasonic reception signal and calculating an elastic modulus of the eyeball surface corresponding to the movement amount of the eyeball surface. The method according to claim 1,
The signal generator is
A first driving mode for applying a reference signal serving as a starting point for measuring the amount of movement of the medium, a second driving mode for applying a pushing signal for shaking the medium, and the first driving mode immediately after the pushing signal is applied An intraocular pressure measuring device for sequentially driving a third driving mode for applying a detection signal having the same signal type as the driving mode. 13. The method of claim 12,
The signal processor is
Intraocular pressure measurement for measuring the movement amount of the ocular surface and calculating elasticity corresponding to the movement amount by comparing the first ultrasound reception signal obtained when the reference signal is applied with the second ultrasound reception signal obtained when the detection signal is applied Device. 13. The method of claim 12,
The first and third driving modes are
It is the same phase mode for applying the input signal of the same phase to the plurality of piezoelectric elements,
The second driving mode is
An intraocular pressure measuring apparatus in a mixed phase mode in which an input signal of a first phase and an input signal of a second phase that is an inverted phase thereof are applied to a piezoelectric element of a first group and a piezoelectric element of a second group, respectively. 13. The method of claim 12,
The first to third driving modes are
An intraocular pressure measuring apparatus in which all of the input signals of the same phase are applied to the plurality of piezoelectric elements in the same phase mode.

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