KR102578055B1 - Ultrasonic Imaging System using Piezoeletric Luminescence Device and Method Using the Same - Google Patents

Abstract

Provides an ultrasonic imaging system. The ultrasonic imaging system according to an embodiment of the present application includes a substrate 100 made of a piezoelectric material, a light emitting element 200 formed on the substrate 100, and capable of emitting light by a voltage induced in the substrate 100, and a detection device. It is disposed to face the substrate 100 with the target object O in between, and may include an ultrasonic transmitter 300 that transmits ultrasonic waves toward the substrate 100.

Description

Ultrasonic Imaging System using Piezoeletric Luminescence Device and Method Using the Same}

This application relates to a portable ultrasonic image sensor using a piezoelectric light-emitting element combining a piezoelectric material and a light-emitting layer, and to pixel-free ultrasonic tomography using a stack of a piezoelectric material and a light-emitting layer.

Ultrasound technology is used in a wide range of fields such as medicine, military, and architecture. Among these, medical ultrasound imaging technology is widely used for early diagnosis of diseases as it guarantees safety and speed compared to imaging diagnostic methods such as computerized tomography (CT), X-ray, and magnetic resonance imaging (MRI).

Medical ultrasound diagnostic devices largely consist of a piezoelectric energy conversion element (piezoelectric transducer) that transmits and receives ultrasonic waves, a signal processor that amplifies the received signal and converts it into a digital signal, and a display. When an alternating current voltage is applied to the piezoelectric energy conversion element, an ultrasonic pulse is transmitted, and the time of the echo reflected from the object is converted into the distance from the object to obtain two-dimensional cross-sectional information about the thickness direction. This is the principle of reconstructing a 3D image by expanding it in one direction.

This pulse-echo ultrasound technology has been focused on developing more complex arrays of piezoelectric elements or developing high-definition software technology to increase image resolution over the past several decades. This led to the formation of a market structure centered on high-priced products rather than technological diversity.

In the case of ultrasonic diagnostic devices, they consist of a piezoelectric probe, a power supply device that occupies a large volume, an expensive signal processor, and a display, which reduces portability and requires a separate space to accommodate the large volume. , There is a demand for devices that are smaller in size and have improved portability compared to conventional ultrasound diagnostic devices.

Korean Patent Publication No. 10-2019-0037760 relates to a piezoelectric ultrasonic transducer and presents technology for a sensor that performs fingerprint recognition based on a pulse-echo method. However, the ultrasonic transceiver, digital processing unit, and display are separated from each other, and the pulse-echo method is a technology that digitally processes reflected ultrasonic signals to create an image. After going through a digital process related to signal processing, the image coordinates are transmitted to the display. Because it is a method, it requires complex circuit configuration.

Korean Patent Publication No. 10-2019-0037760 (2019.04.08.) U.S. Patent Publication No. 2006-0106307 (May 18, 2006)

This application proposes an ultrasonic image sensor with improved portability, which existing medical ultrasonic diagnostic devices cannot provide. More specifically, the aim is to provide a portable ultrasonic image sensor that combines a piezoelectric transducer and a display into a single device without including an expensive signal processor.

One embodiment of the present application to solve the above problem includes a substrate 100 made of a piezoelectric material, a light emitting device formed on the substrate 100 and capable of emitting light by a voltage induced in the substrate 100. An ultrasonic imaging system is provided, including (200) and an ultrasonic transmitter (300) that is disposed to face the substrate (100) with a detection target object (O) in between, and transmits ultrasonic waves toward the substrate (100).

In one embodiment, the light emitting device 200 includes a light emitting layer 230 that emits light by recombination of electrons and holes, a hole injection layer 210 that provides holes to the light emitting layer 230, and the hole injection layer ( a hole transport layer 220 that transports holes provided from 210), and an electron injection layer 250 that is disposed to face the hole injection layer 210 across the light emitting layer 230 and provides electrons to the light emitting layer 230. , an electron transport layer 240 that transports electrons provided from the electron injection layer 250, a first electrode layer 260 made of a transparent material formed on the hole injection layer 210 or the electron injection layer 250, and the It may include a refractive index matching layer 270 formed on the first electrode layer 260.

In one embodiment, a second power source that is electrically connected to the second electrode layer 400 formed under the substrate 100 and the first electrode layer 260 and the second electrode layer 400 to supply power. It may further include a supply unit (V ₂ ).

In one embodiment, the substrate 100 may include portions with different piezoelectric coefficients in a direction crossing the stacking direction of the second electrode layer 400, the substrate 100, and the light emitting device 200. You can.

In one embodiment, the substrate 100 may be formed of two or more materials with different piezoelectric coefficients.

In one embodiment, it may further include a polymer filler (P) that has a different piezoelectric coefficient from that of the substrate 100 and allows the substrate 100 to be divided into a plurality of units 100a, 100b, and 100c.

In one embodiment, the plurality of units 100a, 100b, and 100c have a piezoelectric coefficient in a direction crossing the stacking direction of the second electrode layer 400, the substrate 100, and the light emitting device 200. It may contain different parts.

In addition, the present invention is an ultrasonic imaging method using the above-described ultrasonic imaging system, wherein the ultrasonic transmitter 300 transmits ultrasonic waves toward the substrate 100 disposed to face the detection target object O. A step of receiving ultrasonic waves on the substrate 100, inducing a voltage according to the intensity of the received ultrasonic waves, and allowing the light emitting device 200 to emit light by the voltage induced in the substrate 100. , provides an ultrasonic imaging method.

According to the present application, since the light-emitting element emits light with the induced voltage generated in the piezoelectric substrate upon reception of the ultrasonic pulse, the signal processor and signal amplifier in the conventional ultrasonic imaging system do not need to be provided, and the volume of the ultrasonic imaging device can be significantly reduced. You can.

In addition, image resolution deterioration due to lateral pressure propagation of ultrasonic pulses can be prevented by adjusting the anisotropy of the piezoelectric coefficient of the piezoelectric substrate and arranging the polymer within the substrate.

In addition, by equipping a separate power supply unit, sufficient luminous intensity can be obtained even with low-intensity ultrasonic pulses, making it possible to apply it to sensitive detection objects such as the human body without difficulty.

Figure 1 is a schematic diagram for explaining a conventional ultrasound imaging system.
Figure 2 is a schematic diagram for explaining an ultrasound imaging system according to an embodiment of the present application.
Figure 3 is a schematic diagram for explaining an ultrasound imaging system according to an embodiment of the present application.
Figure 4 is a schematic diagram for explaining an ultrasound imaging system according to another embodiment of the present application.

Hereinafter, the present application will be described in detail with reference to the attached drawings.

Figure 1 is a diagram for explaining a conventional ultrasound imaging system. In a conventional ultrasonic imaging system, the ultrasonic transceiver 10 transmits ultrasonic pulses toward the object to be detected (O) and receives echo pulses reflected from the object to be detected (O). The echo pulse received in this way was amplified by the signal amplifier 20, converted and processed into a digital signal by the digital conversion processor 30, and finally output to the display 40. However, the signal amplifier 20 for amplifying the echo pulse and the digital conversion processor 30 for signal processing are expensive and have a very large size, which has the disadvantage of greatly reducing portability, and it is difficult to supply power to these devices. A separate power supply unit (not shown) was also required.

Figure 2 is a diagram for explaining an ultrasound imaging system according to an embodiment of the present application. Referring to FIG. 2 , the ultrasonic imaging system according to an embodiment of the present application may include a substrate 100, a light emitting element 200, and an ultrasonic transmitter 300.

The substrate 100 may be made of a piezoelectric material, and the piezoelectric material may refer to a material that generates voltage when mechanical pressure is applied and mechanical deformation occurs when voltage is applied. The substrate 100 according to an embodiment of the present application includes Lead zirconate titanate, BaTiO ₃ , SrTio ₃ , polyvinylidene fluoride (PVDF), Polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), Zr-doped HfO ₂ , Al-doped HfO ₂ , One or more materials selected from the group consisting of Si-doped HfO ₂ , Ga-doped HfO ₂ , Y-doped HfO _2, polyamides, polyimide, liquid crystal polymers, Parylene-C, cellular polypropylene, cellular polyethylene-naphthalate, and voided charge polymers It can be formed as

The light emitting device 200 is a part that emits light by the voltage induced in the substrate 100 by the piezoelectric effect, and emits light by recombination of electrons and holes. A detailed explanation of this will be provided later.

The ultrasonic transmitter 300 is disposed to face the substrate 100 with the detection target object O in between, and is a part that transmits ultrasonic pulses toward the detection target object O. A conventional ultrasonic transmitter capable of transmitting ultrasonic pulses can be applied, and a detailed description thereof will be provided later.

When the ultrasonic transmitter 300 transmits an ultrasonic pulse toward the object to be detected (O), the intensity of the pulse that reaches the substrate 100 at the part where the object to be detected (O) is located and where the object to be detected (O) is not located in the movement path of the ultrasonic pulse will be different. As shown in FIG. 2, a weak intensity ultrasonic pulse will be received on the substrate 100 located above the portion where the detection target object O is located, and on the upper side of the portion where the detection target object O is not located. The substrate 100 located at will receive an ultrasonic pulse of stronger intensity. The magnitude of the voltage induced in the substrate 100 will vary in proportion to the intensity of the received ultrasonic pulse, and the intensity of light output from the light emitting device 200 will vary accordingly, through which ultrasonic image reading can be performed. there is.

The substrate 100 and the ultrasonic transmitter 300 may be surrounded by a medium, and the medium serves to facilitate the transmission of ultrasonic pulses. For example, materials such as ultrasonic gel, water, metal, ceramic, and plastic may be used.

Hereinafter, an ultrasound imaging system according to an embodiment of the present application will be described in more detail with reference to FIGS. 3 and 4.

Figure 3 is a diagram for explaining an ultrasound imaging system according to an embodiment of the present application.

Referring to FIG. 3, the ultrasonic imaging system of the present application may include a substrate 100, a light emitting element 200, and an ultrasonic transmitter 300.

The substrate 100 may be made of a piezoelectric material, and is a part that receives ultrasonic pulses transmitted from the ultrasonic transmitter 300 and induces voltage by the piezoelectric effect. A detailed description of this has been described above, so it will be omitted.

The substrate 100 is preferably made of a piezoelectric material so that the piezoelectric coefficient is different for each part of the substrate 100. For example, by forming a portion with a high piezoelectric coefficient and a portion with a low piezoelectric coefficient at an intersection in the lateral direction of the substrate 100, the contrast sensitivity of the image finally output from the light emitting device 200 can be improved. This is because, when an ultrasonic pulse is received on the substrate 100, the pressure of the received ultrasonic pulse propagates not only in the longitudinal direction but also in the lateral direction, causing interference, which may result in an inaccurate image being output. By controlling anisotropy (i.e., the piezoelectric coefficient of a random point is different from another random point), contrast sensitivity can be improved and high-resolution images can be output. Related explanations will be described in detail later.

The light emitting device 200 may be formed on the substrate 100 and is a part that outputs an image by emitting light by a voltage induced in the substrate 100.

Referring to FIG. 3, the light emitting device 200 includes a hole injection layer 210, a hole transport layer 220, a light emitting layer 230, an electron transport layer 240, an electron injection layer 250, a first electrode layer 260, and It may include a refractive index matching layer 270.

The hole injection layer 210 and the hole transport layer 220 are used to transfer holes to the light emitting layer 230, and serve to lower the driving voltage by increasing quantum efficiency. The hole transport layer 220 may use a known hole transport material, and in one embodiment of the present application, poly (3-hexylthiophene) (P3HT), pentacene, naphthalene dimide, 1,4-diketopyrrolo[3,4-c] pyrrole (DPP), 4,4'-bis[N-(1-napthyl)-N-phenyl-amino] biphenyl (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)- 1,1'-biphenyl-4,4'-diamine (TPD), 9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4-(N-(4-sec-butylphenyl))diphenylamine) ] (TFB), NiOx, and 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) may be a thin film structure made of one or more materials selected from the group consisting of, and the thickness of the hole transport layer 220 may be 50 nm or less.

The light-emitting layer 230 is formed by recombining holes injected from the hole injection layer 210 and the hole transport layer 220 and electrons injected from the electron injection layer 250 and the electron transport layer 240, and the aciton falls to the ground state. It is a layer that emits light. Generally, it is also referred to as an organic light-emitting layer including a hole injection layer 210, a hole transport layer 220, a light-emitting layer 230, an electron transport layer 240, and an electron injection layer 250. In the examples of the present application, 4,48,49-tri(N-carbazolyl) triphenylamine (TCTA) doped with fac tris(2-phenylpyridine)iridium [Ir(ppy)3], fac tris(2-phenylpyridine)iridium [ Ir(ppy)3] doped 4,4 -N,N -dicarbazole-biphenyl (CBP), iridium (III)bis [2-methyldibenzo-(f,h) quinoxaline](acetylacetonate) (Ir(MDQ)2 (acac)) doped 3,59-N,N9-dicarbazolebenzene (mCP), Ir(MDQ)2(acac) doped 2,29,20(1,3,5-benzenetriyl)tris-(1- A thin film made of any material selected from the group consisting of mCP doped with phenyl-1H-benzimidazole) (TPBi) and iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C29] picolinate (FIrpic) structure, and the thickness of the light emitting layer 230 may be 30 nm or less.

The electron transport layer 240, the electron injection layer 250, and the first electrode layer 260 are used to transfer electrons to the light emitting layer 230.

The first electrode layer 260 is a cathode that supplies electrons to the light emitting layer 230, and may be made of a transparent material so that an image can be output through the refractive index matching layer 260, which will be described later. More specifically, metals such as Ag, Al, Ca, Mg, Au, Pt, Mo, Cr, Mg:Ag, Indium tin Oxide (ITO), Indium Zinc Oxide (IZO), Aluminum Tin Oxide (ATO), Aluminum Zinc It may be a layered structure of one or more materials selected from the group consisting of oxide (AZO), carbon nanotube, silver nanowire, Al/ITO, and Ag/ITO.

More specifically, when the first electrode layer 260 is made of a Mg:Ag material, it may be composed of a composition ratio of Mg:Ag=10:1, and the thickness may be 30 nm or less.

The electron injection layer 250 may be made of a material that has the function of facilitating injection of electrons supplied from the first electrode layer 260, and may be a mixture of LiF, NaCl, CsF, Li ₂ O, BaO, CsCO ₃ , and BCP. The same material can be applied.

The electron transport layer 240 is designed to facilitate electron injection and transport by lowering the energy barrier of electron injection. C60, PC60BM, PC70BM, 3,4,9,10-perylenetetracarboxylic-3,4:9,10-bis-methylimide (Me-PTC), N,N'-di (propoxyethyl) perylene-3, 4, 9, 10-tetracarboxylic diimide (PTCDI), 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA), naphthalene tetracarboxylic anhydride (NTCDA) ), 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), p-bis(triphenylsilyl)benzene (UGH2), 4,7-diphenyl-1,10-phenanthroline (BPhen), tris -(8-hydroxy quinoline) aluminum (Alq3), 3,5'-N,N'-dicarbazole-benzene (mCP), tris[3-(3-pyridyl)-mesityl]borane (3TPYMB), ZnO and TiO ₂ It may be a layered structure of one or more materials selected from the group consisting of, and the thickness of the electron transport layer 240 may be 50 nm or less.

The refractive index matching layer 270 is a portion laminated on the first electrode layer 260, and includes a hole injection layer 210, a hole transport layer 220, a light emitting layer 230, an electron transport layer 240, and an electron injection layer 250. This is a part that reduces the difference in refractive index between the organic light-emitting layer containing and the atmosphere. Generally, in the case of GaN, a nitride that makes up the organic light-emitting layer, the refractive index is about 2.4, and in the case of atmosphere, the refractive index is 1, so the difference is very large. This generates a lot of total internal reflection, which greatly limits the angle of incidence from which light can actually be extracted, resulting in problems in which images are not output properly.

This problem is solved by reducing the refractive index by stacking the refractive index matching layer 270 on the organic light emitting layer. In one embodiment of the present application, the refractive index matching layer 270 made of Alq ₃ , TCTA, TAPC, NPB, or CBP can be applied, and its thickness can be 45 nm.

The ultrasonic transmitter 300 may include a substrate 320 made of a piezoelectric material, electrodes 310 and 330 stacked on the upper and lower sides of the substrate 320, and an impedance matching layer 340, respectively.

The substrate 320 may be made of the same piezoelectric material as the substrate 100 formed below the light emitting device 200.

The electrodes 310 and 330 stacked on the upper and lower sides of the substrate 320 are connected to the first power supply (V ₁ ) and receive an alternating current voltage through the first power supply (V ₁ ), and the electrodes 310 , 330), the substrate 320 generates an ultrasonic pulse by applying an ultrasonic alternating current voltage.

The electrodes 310 and 330 are metals such as Ag, Al, Ca, Mg, Au, Pt, Mo, Cr, Mg:Ag, Indium tin Oxide (ITO), Indium Zinc Oxide (IZO), and Aluminum Tin Oxide (ATO). , Aluminum Zinc Oxide (AZO), carbon nanotube, silver nanowire, Al/ITO, and Ag/ITO.

The impedance matching layer 340 is laminated on the electrode 330 and is a part that suppresses ultrasonic energy transmission loss at the interface. Through this, energy loss of ultrasonic pulses transmitted from the ultrasonic transmitter 300 can be minimized.

Referring to FIG. 3, the ultrasound imaging system of the present application will be described in more detail. The second electrode layer 400 is stacked on the lower part of the substrate 100, and when the second power supply unit (V ₂ ) applies a direct current voltage between the first electrode layer 260 and the second electrode layer 400, electrons and holes meet. Light is emitted from the light emitting layer 230.

As described above, the substrate 100 is formed in a transverse direction, that is, in a direction that intersects the stacking direction of the second electrode layer 400, the substrate 100, and the light emitting device 200, with a portion having a high piezoelectric coefficient and a portion having a low piezoelectric coefficient intersecting. You can. Accordingly, the phenomenon of the piezoelectric voltage induced in the substrate 100 propagating laterally and deteriorating the resolution of the ultrasonic image can be reduced. Accordingly, it is possible to solve the above problem by forming the substrate 100 from a plurality of different materials such as 1-3 composite so that parts with high and low piezoelectric coefficients are formed alternately.

Referring to FIG. 4, an ultrasound imaging system according to another embodiment of the present application will be described in detail.

FIG. 4 is different from FIG. 3 in that a polymer filler P having a different piezoelectric coefficient from the substrate 100 penetrates the substrate 100.

The polymer filler (P) penetrates the substrate 100 to divide the substrate 100 into a plurality of units 100a, 100b, and 100c (i.e., the plurality of units are formed in a checkerboard arrangement), and the substrate 100 This is the part that prevents the pressure of the ultrasonic pulse received from propagating laterally. The polymer filler (P) is preferably a dielectric material with high insulating properties, and has a different piezoelectric coefficient from that of the substrate 100 or is preferably a non-piezoelectric material. That is, the polymer filler (P) according to the embodiment of the present application is polyvinylidene fluoride (PVDF), PVDF-TrFE (trifluoroethylene), polyamides, polyimide, liquid crystal polymers, Parylene-C, cellular polypropylene, cellular polyethylene-, which are used as piezoelectric polymers. It can be a material with non-piezoelectric properties, as well as naphthalate and voided charge polymers.

Due to the presence of the polymer filler (P), the substrate 100 is separated into a plurality of units 100a, 100b, and 100c, and even if the pressure of the ultrasonic pulse is propagated in the lateral direction, the polymer filler (P) absorbs it, so that the ultrasonic wave Transverse pulse propagation prevents any one unit 100a from influencing the adjacent unit 100b. Accordingly, the resolution of the light emitting device 200 can be improved.

In addition, the plurality of units 100a, 100b, and 100c divided by the polymer filler (P) are also arranged in the transverse direction, that is, crossing the stacking direction of the second electrode layer 400, the substrate 100, and the light emitting device 200. Parts with high piezoelectric coefficients and parts with low piezoelectric coefficients may be formed at intersections in each direction. Accordingly, the phenomenon of the piezoelectric voltage induced in the plurality of units 100a, 100b, and 100c propagating laterally and deteriorating the resolution of the ultrasonic image can be reduced.

According to the present application described above, since the light emitting element emits light with the induced voltage generated in the piezoelectric substrate upon reception of the ultrasonic pulse, the signal processor and signal amplifier in the conventional ultrasonic imaging system do not need to be provided, reducing the volume of the ultrasonic imaging device. can be significantly reduced.

In addition, image resolution deterioration due to lateral pressure propagation of ultrasonic pulses can be prevented by adjusting the anisotropy of the piezoelectric coefficient of the piezoelectric substrate and arranging the polymer within the substrate.

In addition, by equipping a separate power supply unit, sufficient luminous intensity can be obtained even with low-intensity ultrasonic pulses, making it possible to apply it to sensitive detection objects such as the human body without difficulty.

Above, this specification has been described with reference to the embodiments shown in the drawings so that those skilled in the art can easily understand and reproduce the present application, but these are merely illustrative, and those skilled in the art can make various modifications and equivalent alternatives from the embodiments of the present application. It will be appreciated that embodiments are possible. Therefore, the scope of protection of this application should be determined by the claims.

10: Ultrasonic transceiver
20: signal amplifier
30: digital conversion processor
40: display
100: substrate
100a, 100b, 100c: units
200: light emitting device
210: hole injection layer
220: hole transport layer
230: light emitting layer
240: electron transport layer
250: electron injection layer
260: first electrode layer
270: Refractive index matching layer
300: ultrasonic transmitter
310, 330: electrode
320: substrate
340: Impedance matching layer
400: second electrode layer
O: object to be detected
P: polymer filler
V ₁ : first power supply unit
V ₂ : second power supply unit

Claims (8)

A substrate 100 made of a piezoelectric material;
a light emitting device 200 formed on the substrate 100 and capable of emitting light by a voltage induced in the substrate 100; and
It includes an ultrasonic transmitter 300 that is disposed to face the substrate 100 with a detection object O in between and transmits ultrasonic waves toward the substrate 100,
The light emitting device 200,
A light emitting layer 230 that emits light by recombination of electrons and holes;
a hole injection layer 210 that provides holes to the light emitting layer 230;
a hole transport layer 220 that transports holes provided from the hole injection layer 210;
an electron injection layer 250 that is disposed to face the hole injection layer 210 across the light emitting layer 230 and provides electrons to the light emitting layer 230;
an electron transport layer 240 that transports electrons provided from the electron injection layer 250;
A first electrode layer 260 made of a transparent material formed on the hole injection layer 210 or the electron injection layer 250; and
A refractive index matching layer 270 formed on the first electrode layer 260,
Ultrasound imaging system.
delete According to paragraph 1,
a second electrode layer 400 formed below the substrate 100; and
It further includes a second power supply unit (V ₂ ) electrically connected to the first electrode layer 260 and the second electrode layer 400 to supply power.
Ultrasound imaging system.
According to paragraph 3,
The substrate 100 is,
Comprising portions with different piezoelectric coefficients in a direction crossing the stacking direction of the second electrode layer 400, the substrate 100, and the light emitting device 200,
Ultrasound imaging system.
According to paragraph 4,
The substrate 100 is formed of two or more materials with different piezoelectric coefficients.
Ultrasound imaging system.
According to paragraph 3,
It has a different piezoelectric coefficient from the substrate 100 and further includes a polymer filler (P) that allows the substrate 100 to be divided into a plurality of units 100a, 100b, and 100c.
Ultrasound imaging system.
According to clause 6,
The plurality of units (100a, 100b, 100c) are,
Comprising portions with different piezoelectric coefficients in a direction crossing the stacking direction of the second electrode layer 400, the substrate 100, and the light emitting device 200,
Ultrasound imaging system.
An ultrasonic imaging method using the ultrasonic imaging system according to any one of claims 1 and 3 to 7,
transmitting, by the ultrasonic transmitter 300, ultrasonic waves toward the substrate 100 arranged to face each other with the detection target object O in between;
Receiving ultrasonic waves on the substrate 100 and inducing a voltage according to the intensity of the received ultrasonic waves; and
Including a step of causing the light emitting device 200 to emit light by a voltage induced in the substrate 100.
Ultrasound imaging method.

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