Photoacoustic measurement device having reduced noise level and non-invasive blood glucose measurement device using same

Abstract

A photoacoustic measurement device of the present invention comprises a first housing and a second housing. The first housing accommodates a light source. The second housing accommodates an ultrasonic sensor and is in acoustic contact with the first housing. The characteristic acoustic impedance of a first material constituting the first housing is greater than the characteristic acoustic impedance of a second material constituting the second housing. The first housing further includes an opening through which light generated by the light source is emitted. The second housing further includes an optical path through which the light generated by the light source is guided. The optical path of the second housing is formed in a direction in which the light travels from the opening of the first housing.

Description

Photoacoustic measuring device having reduced noise level and non-invasive blood glucose measuring device using the same

[0001] The present disclosure relates to a photoacoustic measuring device capable of obtaining information regarding components within a sample using photoacoustic phenomena. More specifically, the present disclosure relates to a photoacoustic measuring device capable of reducing noise during photoacoustic measurement.

[0002] Photoacoustic phenomena are events in which a material generates sound when illuminated by light, as it absorbs the light, heats up locally, and undergoes expansion and contraction. The sound waves or ultrasound generated by photoacoustic phenomena can be measured by acoustic sensors and utilized to visualize the internal structure of a material or analyze the components within a sample.

[0003] Meanwhile, blood glucose measurement is crucial in diabetes management. Although blood sampling is the most accurate method, undergoing repeated daily blood draws is quite painful for diabetic patients. Consequently, technologies for non-invasive blood glucose measurement without blood sampling have been developed, and photoacoustic-based non-invasive blood glucose measurement technology is one such example.

[0004] Photoacoustic signals measured with glucose solutions at the laboratory level exhibit characteristic changes depending on glucose concentration, and theoretically, the glucose concentration in the solution can be estimated from the pattern of such changes. However, in practice, when measuring photoacoustic signals on human tissues such as skin, it is not easy to identify changes in blood glucose concentration from the measured photoacoustic signals.

[0005] The technical problem of the present disclosure is to provide a photoacoustic measuring device capable of obtaining more accurate information regarding components within a sample using photoacoustics.

[0006] The technical problem of the present disclosure is to provide a photoacoustic measuring device that is robust to noise and has a miniaturized form factor.

[0007] The technical problems of the present disclosure are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by a person skilled in the art from the description below.

[0008] The means for solving the problem are provided to introduce, in a simplified form, some concepts that are described in more detail in the detailed description of the present disclosure, and are not intended to identify the essential concepts of the present disclosure or to determine the scope of the present disclosure.

[0009] A photoacoustic measuring device according to one aspect of the present disclosure comprises a first housing for internally accommodating an optical element that transmits light generated by a light source, and a second housing that internally accommodates an ultrasonic sensor and is in acoustic contact with the first housing, wherein the characteristic acoustic impedance of a first material forming the first housing and the characteristic acoustic impedance of a second material forming the second housing may be different from each other.

[0010] According to an embodiment, the characteristic acoustic impedance of the first material may be greater than the characteristic acoustic impedance of the second material.

[0011] According to an embodiment, the second housing may further comprise a light path through which light generated by a light source is guided.

[0012] According to an embodiment, the first housing further comprises an opening through which light generated by a light source is emitted, and the light path of the second housing may be formed in the direction in which light travels from the opening of the first housing.

[0013] According to an embodiment, the ultrasonic sensor has an acoustic axis, and the acoustic axis within the second housing may be positioned to intersect the light-induced direction of the optical path within the irradiated sample.

[0014] According to an embodiment, the ultrasonic sensor has an acoustic axis, and the acoustic axis within the second housing may be positioned parallel to the light-induced direction of the optical path within the irradiated sample.

[0015] According to an embodiment, the first housing may further include either one or both of a light source driving unit and an optical element.

[0016] According to an embodiment, the characteristic acoustic impedance of the first material and the characteristic acoustic impedance of the second material can be selected respectively so that when the first housing and the second housing are in contact, the attenuation of noise transmitted from the first housing to the second housing is greater than 3 dB.

[0017] According to an embodiment, the first material of the first housing may be selected from the group including aluminum, alumina, aluminum alloy, stainless steel, carbon steel, magnesium, magnesium alloy, titanium, and titanium alloy.

[0018] According to an embodiment, the second material of the second housing may be selected from the group including synthetic resin, epoxy, silicone, rubber, acrylic, carbon fiber, and glass fiber.

[0019] According to an embodiment, the second housing includes an opening that is open toward the first housing, and a cushioning material received in the opening may be interposed between the ultrasonic sensor and the first housing.

[0020] According to an embodiment, an intermediate layer made of a third material having a characteristic acoustic impedance to acoustically decouple either or both of the first and second materials may be interposed between mutually opposing surfaces of the first housing and the second housing.

[0021] According to an embodiment, the first housing and the second housing can be mechanically connected.

[0022] According to an embodiment, the photoacoustic measuring device further includes a case that encloses both the first housing and the second housing, and the case can be exposed so that light emitted from a light source is incident on the irradiated sample and the measuring surface of the ultrasonic sensor can acoustically contact the irradiated sample.

[0023] According to an embodiment, the photoacoustic measuring device may further include a control unit that controls the operation of a light source in a first housing and an analysis unit that analyzes measurement data obtained from an ultrasonic sensor in a second housing.

[0024] According to the embodiments, the measurement data may include quantitative or qualitative information regarding the components of a specific substance within the sample under investigation.

[0025] According to the embodiment, the measurement data may include quantitative or qualitative information regarding the concentration of glucose in the dermis layer of the skin or in the blood vessels.

[0026] In another embodiment, the characteristic acoustic impedance of the first material may be smaller than the characteristic acoustic impedance of the second material.

[0027] According to an embodiment, the first material of the first housing may be selected from the group including synthetic resin, epoxy, silicone, rubber, acrylic, carbon fiber, and glass fiber.

[0028] According to the embodiment, the second material of the second housing may be selected from the group including aluminum, alumina, aluminum alloy, stainless steel, carbon steel, magnesium, magnesium alloy, titanium, and titanium alloy.

[0029] According to the photoacoustic measuring device according to the technical concept of the present disclosure, information regarding components within a sample can be obtained more accurately by using photoacoustics.

[0030] According to the photoacoustic measuring device according to the technical concept of the present disclosure, it is possible to provide robust performance against noise while having a miniaturized form factor.

[0031] The effects obtainable from the exemplary embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art from the description of the exemplary embodiments of the present disclosure below. That is, unintended effects resulting from the implementation of the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0032] The embodiments, aspects, advantages, and other features of the present disclosure will be better understood by reading the following detailed description with reference to the accompanying drawings, in which the same letters in the drawings indicate the same parts throughout the drawings.

[0033] FIG. 1 is a schematic projection illustrating a photoacoustic measuring device according to embodiments.

[0034] FIG. 2 is a schematic block diagram illustrating a photoacoustic measuring device according to embodiments.

[0035] FIG. 3 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are combined with each other within a photoacoustic measuring device according to embodiments.

[0036] FIG. 4 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are joined together by an intermediate layer within a photoacoustic measuring device according to embodiments.

[0037] FIG. 5 is a schematic cross-sectional view illustrating a structure in which a cushioning material is interposed between the first housing and the ultrasonic sensor when the first housing and the second housing are coupled together in a photoacoustic measuring device according to embodiments.

[0038] FIG. 6 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are mechanically joined to each other within a photoacoustic measuring device according to embodiments.

[0039] FIG. 7 is a schematic cross-sectional view illustrating a structure that provides acoustic coupling between an ultrasonic sensor and an irradiated sample when a first housing and a second housing are coupled together in a photoacoustic measuring device according to embodiments.

[0040] FIG. 8 is a schematic cross-sectional view illustrating a structure in which the acoustic axis of the ultrasonic sensor and the optical axis of the light are not parallel to each other when the first housing and the second housing are combined in a photoacoustic measuring device according to embodiments.

[0041] FIG. 9 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are combined with each other within a photoacoustic measuring device according to other embodiments.

[0042] For example, some components of the device in the drawings may be represented by conventional symbols. The drawings may primarily depict specific details relevant to understanding the embodiments of the present disclosure, and details that are readily understood by a person skilled in the art may be omitted or simplified to maintain the visibility of the drawings. Some components of the drawings may not be drawn to their actual proportions for the sake of simplification or convenience of explanation.

[0043] The terms used in the embodiments have been selected to be as widely used as possible in consideration of the context of this disclosure; however, these may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases where the applicant has arbitrarily selected a term, its meaning will be described in detail in the relevant description. Therefore, terms used in this disclosure should be defined not merely by their names, but based on their meanings and the overall context of this disclosure.

[0044] Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art as described in this disclosure.

[0045] When a part of a specification is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "part" or "module" as used in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or as a combination of hardware and software.

[0046] Throughout this specification, terms such as acoustics, acoustic waves, sound waves, sound, sound pressure, pressure waves, elastic waves, noise, mechanical vibration, etc. relate to waves that propagate within a specimen accompanied by positional changes of particles of a medium in air or within a solid to semi-solid, liquid, or organic tissue specimen, depending on the context.

[0047] Hereinafter, embodiments will be described in detail with reference to the drawings.

[0048] FIG. 1 is a schematic projection view illustrating a photoacoustic measuring device according to embodiments, and FIG. 2 is a schematic block diagram illustrating a photoacoustic measuring device according to embodiments. FIG. 3 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are combined with each other within a photoacoustic measuring device according to embodiments.

[0049] Referring to FIGS. 1, 2 and 3 together, the photoacoustic measuring device (1) may include a first housing (10), a light source (20), a light source driving unit (21), a first optical element (22), a second housing (30), an ultrasonic sensor (40), an electronic circuit element (60), a battery (65), and a case (70).

[0050] According to an embodiment, the first housing (10) may accommodate a light source (20). More generally, the first housing (10) may be equipped with a light source (20) so that light generated by the light source (20) can be transmitted within the first housing (10). For example, the light source (20) may be a light-emitting diode (LED) or a laser diode (LD) that directly emits light.

[0051] According to an embodiment, the first housing (10) may contain a light source driving unit (21) for driving a light source (20). The light source driving unit (21) may drive the light source (20) by supplying power to the light source (20) with a predetermined light output and light emission time.

[0052] According to an embodiment, the first housing (10) may further contain one or more first optical elements (22) necessary to guide light generated by the light source (20) and to control optical properties. For example, the first optical element (22) is any one or more combinations of optical elements such as a lens, a zoom lens, a reflective mirror, a dichroic mirror, a beam splitter, a prism, an optical fiber, a grating, a polarizer, etc., and is not limited to the elements listed herein. The light generated by the light source (20) may pass through the first optical elements (22) while being transmitted within the first housing (10).

[0053] According to an embodiment, the first housing (10) may contain a light source (20) or one or more first optical elements (22), while not containing a light source driving unit (21).

[0054] The first housing (10) may include a first optical opening (11) so that light generated by the light source (20) can be finally emitted from the first housing (10) toward the irradiated sample (90). The first housing (10) may further include a port (12) formed to be electrically connected to other electronic circuit elements (60) outside the first housing (10) when the light source driver (21) is built into it.

[0055] According to an embodiment, the electronic circuit elements (60) may include a control unit (61) that controls the operation of a light source (20) within a first housing (10) and an analysis unit (62) that analyzes measurement data obtained from an ultrasonic sensor (40) within a second housing (30). According to an embodiment, the irradiated sample is skin, and the measurement data may include quantitative or qualitative information regarding the components of a specific substance within the dermal layer of the skin, for example, glucose concentration information. According to an embodiment, the irradiated sample is blood within a subcutaneous blood vessel, and the measurement data may include quantitative or qualitative information regarding the components of a specific substance within the blood, for example, oxygen saturation or glycated hemoglobin concentration information. The electronic circuit elements (60) may be implemented, for example, as a processor, memory, storage, a Neural Processing Unit (NPU), a communication module, etc.

[0056] The second housing (30) can internally secure the ultrasonic sensor (40). The ultrasonic sensor (40) can detect photoacoustics transmitted from the irradiated sample (90) by acoustically contacting the measurement surface with the irradiated sample (90). According to an embodiment, the second housing (30) can secure most of the body of the ultrasonic sensor (40) by embedding or accommodating it in its internal space, excluding the measurement surface or output port of the ultrasonic sensor (40). According to an embodiment, even if the second housing (30) does not accommodate most of the body of the ultrasonic sensor (40) in its internal space, it can secure the ultrasonic sensor (40) so that it remains separated from the first housing (10) without physically contacting it directly, and furthermore, so that the ultrasonic sensor (40) does not deviate from the measurement position on the irradiated sample (90) during measurement. The fact that the second housing (30) is acoustically in contact with the first housing (10) means that the second housing (30) is in direct contact with the first housing (10), or even if it is not, it is located within a range that is not substantially different from the case of direct contact from an acoustic perspective.

[0057] The case (70) may accommodate the first housing (10), the second housing (30), and the electronic circuit element (60) inside. According to an embodiment, the case (70) may be formed to expose a portion of the first housing (10) or the second housing (30) to the outside. For example, a portion of the second housing (30) may be exposed to the outside so that light generated by the light source (20) may be incident on the irradiated specimen (90), for example, the skin, at a predetermined angle of incidence, for example, perpendicularly, and so that the ultrasonic sensor (40) may be in direct contact with the irradiated specimen (90), for example, the skin. According to an embodiment, the irradiated specimen (90) may be a portion of body tissue. For example, the irradiated specimen (90) may be a portion of body tissue to which light can be irradiated from the outside, such as skin, mucous membrane, epithelial layer, blood vessels, subcutaneous fat, blood, etc. In another example, the irradiated specimen (90) may be collected blood, body fluid, or a specimen removed for surgery or tissue biopsy. According to an embodiment, the irradiated sample (90) may be a part of animal or plant tissue. For example, the irradiated sample (90) may be meat, fish, fruit, etc. According to an embodiment, the irradiated sample (90) may be a solid, semi-solid, gel, or liquid organic or inorganic sample. If light is incident on an object and the photoacoustics caused by a specific component inside can be measured, that object may correspond to the irradiated sample (90) of the present invention, and is not limited to the objects listed herein.

[0058] According to an embodiment, the photoacoustic measuring device (1) may, in particular, induce a photoacoustic effect in the dermal layer of the skin by irradiating the skin with laser pulses of a predetermined wavelength and measuring the generated ultrasonic sound to measure quantitative or qualitative information of a specific substance in the dermal layer, for example, the concentration of glucose. According to an embodiment, the photoacoustic measuring device (1) may measure oxygen saturation, glycated hemoglobin concentration, etc. by irradiating a blood vessel with laser pulses of a predetermined wavelength.

[0059] According to an embodiment, the first housing (10) and the second housing (30) may be in an acoustic contact relationship with each other. According to an embodiment, vibration, sound, noise, elastic waves, or any other form of mechanical wave may be propagated between the first housing (10) and the second housing (30) by direct contact or point contact, or indirectly by interposing another object.

[0060] A photoacoustic measuring device (1) is equipped with a light source (20) and an ultrasonic sensor (40) to measure ultrasonic sound generated by a mechanism known as a photoacoustic phenomenon. The acoustic signal measured by the ultrasonic sensor (40) may include not only ultrasonic sound caused by photoacoustics but also sound caused by other causes.

[0061] A light source driving unit (21) mounted inside the first housing (10) can generate a pulse current having a predetermined peak voltage value, peak current value, pulse width, and pulse period to pulse drive the light source (20). For example, the light source driving unit (21) can drive the light source (20) by generating a pulse current having a peak voltage of 1V to 100V, a peak current of 0.1A to 10A, a pulse width of 0.05μs to 100ms, and a pulse period of 0.1ms to 1s. Such pulse current can cause weak but measurable mechanical vibrations in various circuit elements.

[0062] Additionally, some of the light energy emitted from the light source (20) is lost before it even leaves the first housing (10), and local photoacoustic phenomena or thermal imbalances that may occur inside the first optical element (22) or the first housing (10) in connection with this loss can also cause minute mechanical vibrations.

[0063] According to the embodiment, even when the light source driving unit (21) is mounted outside the first housing (10), it is generally advantageous for the light source driving unit (21) to be located close to the light source (20), and since the light source driving unit (21) must eventually be physically connected to the light source (20) via a wire, vibrations generated from the light source driving unit (21) can be easily propagated to the first housing (10) surrounding the light source (20).

[0064] Under these various conditions, mechanical vibrations experienced by the first housing (10) are likely to be detected by an ultrasonic sensor if such an ultrasonic sensor is directly mounted on the first housing (10). Accordingly, the acoustic signal measured by such an ultrasonic sensor may include not only the photoacoustic signal intended as light irradiation on the irradiation sample (90) but also unintended mechanical vibrations, and the unintended mechanical vibrations may act as noise and adversely affect the signal-to-noise ratio of the acoustic signal to be measured. This is especially true for applications that measure weak acoustic signals, such as photoacoustics.

[0065] According to an embodiment, in order to prevent or minimize the detection of unintended mechanical vibrations in the ultrasonic sensor (40), the first material forming the first housing (10) may be selected to be different from the second material forming the second housing (30) in terms of characteristic acoustic impedance. Specifically, the first material of the first housing (10) and the second material forming the second housing may each be selected such that the difference in characteristic acoustic impedance between them is sufficiently large, thereby allowing a sufficiently large impedance mismatch between the two materials to occur. For example, in one embodiment, the characteristic acoustic impedance of the first material may be selected to be greater than the characteristic acoustic impedance of the second material, and in another embodiment, the characteristic acoustic impedance of the first material may be selected to be smaller than the characteristic acoustic impedance of the second material, thereby allowing a large impedance mismatch between the two materials to occur.

[0066] Here, the specific acoustic impedance or acoustic characteristic impedance can be defined as follows.

[0067] Characteristic acoustic impedance (Z) = Speed ​​of sound within the material (c) x Material density (p)

[0068] Acoustic impedance (z) = Characteristic acoustic impedance (Z) * Area (S)

[0069] The unit of characteristic acoustic impedance, 10^6 kg / m^2 s, can be denoted as "MRy" below.

[0070] At the boundary between objects of two materials having different characteristic acoustic impedances (Z), mechanical waves such as vibrations transmit or reflect through the boundary surface. In this case, the transmission coefficient (T) and the reflection coefficient (R) can be defined as follows.

[0071]

[0072]

[0073] Specifically, when mechanical waves such as vibrations propagate from the first housing (10) of the first material to the second housing (30) of the second material, if the amount absorbed during the propagation process is ignored, the mechanical waves are reflected from the interface by approximately the ratio of the reflection coefficient (R) and returned to the first housing (10), and are transmitted to the second housing (30) by passing through the interface by approximately the ratio of the transmission coefficient (T).

[0074] According to an embodiment, the first and second materials may be selected to attenuate mechanical waves generated in the first housing (10) by 3 dB or more until they are transmitted to the second housing (30). According to an embodiment, the first and second materials may be selected so that the transmission coefficient (T) from the first housing (10) to the second housing (30) is 0.5 or less.

[0075] In one embodiment in which the characteristic acoustic impedance of the first material is selected to be greater than the characteristic acoustic impedance of the second material, the first material may be selected from, for example, aluminum, alumina, aluminum alloy, stainless steel, carbon steel, magnesium, magnesium alloy, titanium, titanium alloy, and the second material may be selected from synthetic resin, epoxy, silicone, rubber, acrylic, but is not limited to the listed materials.

[0076] In another embodiment in which the characteristic acoustic impedance of the first material is selected to be smaller than the characteristic acoustic impedance of the second material, the first material may be selected from synthetic resin, epoxy, silicone, rubber, and acrylic, and the second material may be selected from, for example, aluminum, alumina, aluminum alloy, stainless steel, carbon steel, magnesium, magnesium alloy, titanium, and titanium alloy, but is not limited to the listed materials.

[0077] Based on various literature and datasheets at room temperature, it is known that aluminum 1100-0 has an MRY of approximately 17.1 MRY, aluminum 2024-T4 has an MRY of approximately 7.6 MRY, stainless steel 304 has an MRY of approximately 44.6–45.4 MRY, AZ31B magnesium alloy has an MRY of approximately 10.32 MRY, tin has an MRY of approximately 24.2 MRY, and zinc has an MRY of approximately 29.6 MRY. However, these figures may vary depending on measurement conditions such as material grade, manufacturing conditions, and temperature.

[0078] According to the embodiments, examples of materials having a relatively small characteristic acoustic impedance include ABS resin about 2.3 MRy, polycarbonate about 2.7 MRy, polyethylene about 2.9 MRy, polypropylene about 2.3 MRy, (boron) epoxy about 6.4 MRy, silicone rubber about 1.4 MRy, natural rubber about 1.7 MRy, acrylic about 3.2 MRy, etc., but are not limited thereto, and actual values ​​may vary depending on conditions such as material, composition, and temperature. Accordingly, the first housing (10) and the second housing (30) may be formed from the first material and the second material having different characteristic acoustic impedances, and the transmission of unintended mechanical waves may be suppressed by impedance mismatch between these materials. For example, when an unintended mechanical wave propagates from the first housing (10) to the second housing (30), the transmission coefficient (T) is determined according to the difference in characteristic acoustic impedance of the materials forming the two housings, and a corresponding attenuation may occur.

[0079] In one embodiment, when a combination of a material having a relatively large characteristic acoustic impedance and a material having a relatively small characteristic acoustic impedance is applied, the transmission coefficient (T) can be, for example, about 0.24, and attenuation of about 12.4 dB can be expected. In another embodiment, when a combination of materials with a larger impedance difference is applied, the transmission coefficient (T) can be, for example, about 0.098, and attenuation of about 20.2 dB can be obtained. However, the above values ​​may vary depending on conditions such as the type, grade, bonding structure, contact conditions, thickness, temperature, and frequency band of the wave. Accordingly, the photoacoustic measuring device (1) according to the embodiments may be less affected by mechanical waves generated by the light source driving unit or the light source, and the intended photoacoustic signal from the sample can be measured more accurately.

[0080] According to the embodiment, the second material may further have thermal insulation, flame retardancy, non-combustibility, or flame resistance.

[0081] The ultrasonic sensor (40) may have directivity according to its internal structure and may have an acoustic axis along the direction in which the directivity is greatest. According to an embodiment, the ultrasonic sensor (40) may be positioned so that the acoustic axis is parallel to the direction of incidence of light incident on the irradiated sample (90), or the acoustic axis may be positioned so that it faces the photoacoustic generating region inside the irradiated sample (90).

[0082] According to an embodiment, the second housing (30) may further include a barrel portion (33) that provides an optical path (50) from the first optical opening (11) to the second optical opening (51) so that light emitted from the light source (20) is guided to an irradiation sample (90), such as skin, after passing through the first optical opening (11). For example, the barrel portion (33) may provide an optical path (50) that is a cylindrical or truncated conical empty space between the first optical opening (11) of the first housing (10) and the irradiation sample (90).

[0083] According to an embodiment, the direction of the central axis of the barrel portion (33) may generally coincide with the direction of the acoustic axis of the ultrasonic sensor (40) housed in the second housing (30). In other words, the central axis of the barrel portion (33) and the acoustic axis of the ultrasonic sensor (40) may be parallel to each other.

[0084] Accordingly, even if the optical or acoustic characteristics of the investigation sample (90), light incidence conditions, external environment, etc., change depending on the application, instead of completely redesigning the first housing (10) and the first optical elements (22) inside, it is possible to respond minimally by only changing the design of the second housing (30).

[0085] According to an embodiment, a second optical element (52) capable of controlling optical properties while light generated by a light source (20) passes through an optical path (50) within the second housing (30) may be further provided. For example, the second optical element (52) may be any one or a combination of two or more of a lens, a zoom lens, a reflective mirror, a dichroic mirror, a beam splitter, a prism, an optical fiber, a grating, and a polarizer.

[0086] According to an embodiment, the second housing (30) may further include an optically transparent cover (35) to protect the optical path (50) and further protect the first optical aperture (11). The cover (35) may be appropriately coated to block ultraviolet rays or prevent fogging.

[0087] FIG. 4 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are joined together by an intermediate layer within a photoacoustic measuring device according to embodiments.

[0088] Referring to FIG. 4, the photoacoustic measuring device (4) according to the embodiments may include a first housing (10), a light source (20), a light source driving unit (21), a first optical element (22), a second housing (30), an ultrasonic sensor (40), an electronic circuit element (60), a case (70), and an intermediate layer (80).

[0089] An intermediate layer (80) may be interposed on at least some of the opposing surfaces of the first housing (10) and the second housing (30). According to an embodiment, the intermediate layer (80) may be selected from a material having a characteristic acoustic impedance capable of acoustically decoupling between the first housing (10) and the second housing (30). For example, the material of the intermediate layer (80) may be selected such that the respective transmission coefficients for the first housing (10) material and the second housing (30) material are each 0.5 or less, or the total transmission coefficient is 0.5.

[0090] According to an embodiment, the intermediate layer (80) may be selected from materials having a characteristic acoustic impedance that is acoustically decoupled with respect to the first housing (10) and acoustically coupled with respect to the second housing (30). For example, the material of the intermediate layer (80) may be selected such that the transmittance coefficient with respect to the material of the first housing (10) is 0.5 or less, while the transmittance coefficient with respect to the material of the second housing (30) is 0.5 or more.

[0091] According to an embodiment, the intermediate layer (80) may be selected from adhesive materials capable of permanently or temporarily bonding the second housing (30) to the first housing (10). For example, the intermediate layer (80) after the selected adhesive material has exhibited adhesive properties may be acoustically decoupled with respect to the first housing (10) and acoustically coupled with respect to the second housing (30).

[0092] According to the embodiment, the intermediate layer (80) may be selected from an insulating material or a refractory material that blocks heat transfer between the first housing (10) and the second housing (30).

[0093] According to an embodiment, the intermediate layer (80) may be any one of a synthetic resin film, a rubber plate, a sound-absorbing film, an acoustic metamaterial, an adhesive film, a fabric, a non-woven fabric, a thermal insulation film, a fire-resistant film, or a combination thereof.

[0094] According to an embodiment, if the material applied to the first housing (10) or the second housing (30) includes a metal capable of anodizing (e.g., aluminum, magnesium, titanium, or an alloy thereof), the housing may have an oxide film on its surface through anodizing treatment. In this case, the oxide film may have a relatively high characteristic acoustic impedance (e.g., about 40 MRy level), and accordingly, the oxide film may function as an intermediate layer (80) by inducing acoustic decoupling between the housings. However, the characteristic acoustic impedance value may vary depending on the material, the composition / thickness of the film, manufacturing conditions, temperature, etc.

[0095] FIG. 5 is a schematic cross-sectional view illustrating a structure in which a cushioning material is interposed between the first housing and the ultrasonic sensor when the first housing and the second housing are coupled together in a photoacoustic measuring device according to embodiments.

[0096] Referring to FIG. 5, the photoacoustic measuring device (5) according to the embodiments may include a first housing (10), a light source (20), a light source driving unit (21), a first optical element (22), a second housing (30), an ultrasonic sensor (40), an electronic circuit element (60), a case (70), and a cushioning material (81).

[0097] One side of the cushioning material (81) is in close contact with the first housing (10), and the other side is in close contact with the ultrasonic sensor (40) through the opening (32) of the second housing (30), so that the ultrasonic sensor (40) can be fixed so that it does not deviate from the measurement position and maintains its posture during measurement by the photoacoustic measuring device (4). For example, the second housing (30) may be provided with an opening (32) to introduce the ultrasonic sensor (40) into the receiving space inside it, and the cushioning material (81) can be used as a means to fix the ultrasonic sensor (40) after mounting the ultrasonic sensor (40) in the receiving space inside the second housing (30) through the opening (32).

[0098] According to an embodiment, the buffer material (81) may be selected from materials having a characteristic acoustic impedance capable of acoustically decoupling between the first housing (10) and the second housing (30). For example, the material of the buffer material (81) may be selected such that the respective transmission coefficients for the first housing (10) material and the second housing (30) material are each 0.5 or less, or the total transmission coefficient is 0.5.

[0099] According to an embodiment, the buffer material (81) may be selected from materials having a characteristic acoustic impedance that is acoustically decoupled with respect to the first housing (10) and acoustically coupled with respect to the second housing (30). For example, the material of the buffer material (81) may be selected such that the transmittance coefficient with respect to the material of the first housing (10) is 0.5 or less, while the transmittance coefficient with respect to the material of the second housing (30) is 0.5 or more.

[0100] According to the embodiment, the cushioning material (81) may be any one of synthetic resin, rubber, sound-absorbing material, acoustic metamaterial, thermal insulation material, refractory material, or a combination thereof.

[0101] FIG. 6 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are mechanically joined to each other within a photoacoustic measuring device according to embodiments.

[0102] Referring to FIG. 6, the photoacoustic measuring device (6) according to the embodiments may include a first housing (10), a light source (20), a light source driving unit (21), a first optical element (22), a second housing (30), an ultrasonic sensor (40), an electronic circuit element (60), and a case (70), and the first housing (10) and the second housing (30) may be mechanically connected by fastening units (36, 37). For example, the fastening units (36, 37) may be implemented using known fastening methods such as elastic fastening, snap fastening, or screw fastening.

[0103] FIG. 7 is a schematic cross-sectional view illustrating a structure that provides acoustic coupling between an ultrasonic sensor and an irradiated sample when a first housing and a second housing are coupled together in a photoacoustic measuring device according to embodiments.

[0104] Referring to FIG. 7, the photoacoustic measuring device (7) according to the embodiments may include a first housing (10), a light source (20), a light source driving unit (21), a first optical element (22), a second housing (30), a barrel unit (33), an acoustic coupler (38), an ultrasonic sensor (40), an electronic circuit element (60), and a case (70).

[0105] The acoustic coupler (38) can provide acoustic impedance matching between the ultrasonic sensor (40) and the investigation sample (90). To this end, the fourth material constituting the acoustic coupler (38) may be selected as a material having a characteristic acoustic impedance value that is smaller than the characteristic acoustic impedance of the ultrasonic sensor (40) and larger than the characteristic acoustic impedance of the investigation sample (90).

[0106] According to an embodiment, an acoustic coupler (38) may extend to the second optical opening (51) to perform the role of the cover (35) instead of the cover (35). According to an embodiment, conversely, the cover (35) may extend to the measurement opening (31) of the ultrasonic sensor (40) to perform the role of the acoustic coupler (38).

[0107] FIG. 8 is a schematic cross-sectional view illustrating a structure in which the acoustic axis and the optical axis of an ultrasonic sensor are not parallel to each other when the first housing and the second housing are combined in a photoacoustic measuring device according to embodiments.

[0108] Referring to FIG. 8, the photoacoustic measuring device (8) according to the embodiments may include a first housing (10), a light source (20), a light source driving unit (21), a first optical element (22), a second housing (30), a barrel unit (34), an acoustic coupler (39), an ultrasonic sensor (40), an electronic circuit element (60), and a case (70).

[0109] The central axis of the barrel (34) and the acoustic axis of the ultrasonic sensor (40) housed in the second housing (30) may be arranged to intersect on the incident surface of an irradiation sample (90), such as skin, or within it. In contrast, in the embodiments illustrated in FIGS. 3 through 7 and FIG. 9, the central axis of the barrel (34) and the acoustic axis of the ultrasonic sensor (40) in the second housing (30) may be substantially parallel to each other.

[0110] According to the embodiment, the barrel portion (34) may be implemented in a cylindrical shape such that the cross-sectional area of ​​the inner barrel is constant, or in a truncated cone shape such that the cross-sectional area of ​​the barrel gradually decreases and tapes.

[0111] According to an embodiment, the central axis of the barrel (34) may be incident perpendicularly on the irradiation sample (90), and the acoustic axis of the ultrasonic sensor (40) may be inclined to intersect the central axis of the barrel (34) within the irradiation sample (90), or, to express it differently, toward a photoacoustic generating area (not shown) within the irradiation sample (90).

[0112] The acoustic coupler (39) can provide acoustic impedance matching between the ultrasonic sensor (40) and the investigation sample (90). To this end, the fourth material constituting the acoustic coupler (39) may be selected as a material having a characteristic acoustic impedance value that is smaller than the characteristic acoustic impedance of the ultrasonic sensor (40) and larger than the characteristic acoustic impedance of the investigation sample (90). The acoustic coupler (39) may be implemented in a rounded wedge shape to fit the space between the measurement opening (31) and the investigation sample (90).

[0113] FIG. 9 is a schematic cross-sectional view illustrating a structure in which a first housing and a second housing are combined with each other within a photoacoustic measuring device according to other embodiments.

[0114] Referring to FIG. 9, the photoacoustic measuring device (9) according to the embodiments may include a first housing (10), a light source (20), a light source driving unit (21), a first optical element (22), a second housing (30), an ultrasonic sensor (40), an electronic circuit element (60), and a case (70).

[0115] According to an embodiment, the second housing (30) may be positioned parallel to the first housing (10) such that the measurement surface of the ultrasonic sensor (40) is located at the same level as the first optical opening (11).

[0116] Compared to the photoacoustic measuring devices (4 to 8) of FIGS. 4 to 8, in the photoacoustic measuring devices (4 to 8), light emitted from a light source (21) passes through a first optical aperture (11) and an optical path (50) and enters a sample (90) for irradiation, and an ultrasonic sensor (40) is positioned in close proximity to the optical path (50), with only a partition of the second housing (30) between the optical path (50) and the ultrasonic sensor (40). Therefore, assuming other conditions are the same, the photoacoustic measuring devices (4 to 8) may be more advantageous for photoacoustic measurement in terms of the distance between the ultrasonic sensor (40) and the photoacoustic generation area compared to the photoacoustic measuring device (9). On the other hand, assuming other conditions are the same, the photoacoustic measuring device (9) may be more advantageous for miniaturization compared to the photoacoustic measuring devices (4 to 8).

[0117] As described above, exemplary embodiments have been disclosed in the drawings and specification. Although specific terms have been used to describe the embodiments in this specification, they are used only for the purpose of explaining the technical concept of the present disclosure and are not intended to limit the meaning or the scope of the present disclosure as defined in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0118] [Explanation of the symbol]

[0119] 1 Photoacoustic measuring device

[0120] 10 1st Housing

[0121] 11 First optical aperture

[0122] 20 light sources

[0123] 21 Light source driving unit

[0124] 22 First optical element

[0125] 30 2nd Housing

[0126] 31 measuring opening

[0127] 33 Telescope tube

[0128] 40 ultrasonic sensors

[0129] 50 Gwangmang-ro

[0130] 51 Second optical aperture

[0131] 52 Second optical element

[0132] 60 Electronic Circuit Elements

[0133] 70 cases

[0134] 80 middle layer

[0135] 81 cushioning material

[0136] 90 survey samples

Claims

1. A first housing for internally accommodating an optical element that transmits light generated by a light source; and It includes a second housing that internally accommodates an ultrasonic sensor and is in acoustic contact with the first housing, and A photoacoustic measuring device characterized in that the characteristic acoustic impedance of the first material forming the first housing is greater than the characteristic acoustic impedance of the second material forming the second housing.

2. A photoacoustic measuring device according to claim 1, wherein the second housing further comprises an optical path through which light generated by the light source is guided.

3. In claim 2, the first housing further comprises an opening through which light generated by the light source is emitted, and A photoacoustic measuring device characterized in that the optical path of the second housing is formed in the direction in which light travels from the opening of the first housing.

4. A photoacoustic measuring device according to claim 2, wherein the ultrasonic sensor has an acoustic axis, and the acoustic axis within the second housing is arranged to intersect the light-induced direction of the optical path within the irradiated sample.

5. A photoacoustic measuring device according to claim 2, wherein the ultrasonic sensor has an acoustic axis, and the acoustic axis within the second housing is arranged to be parallel to the light-induced direction of the optical path within the irradiated sample.

6. A photoacoustic measuring device according to claim 1, characterized in that the characteristic acoustic impedance of the first material and the characteristic acoustic impedance of the second material are each selected such that when the first housing and the second housing are in contact, the attenuation of noise transmitted from the first housing to the second housing is greater than 3 dB.

7. A photoacoustic measuring device according to claim 1, wherein the first material of the first housing is selected from the group comprising aluminum, alumina, aluminum alloy, stainless steel, carbon steel, magnesium, magnesium alloy, titanium, and titanium alloy.

8. A photoacoustic measuring device according to claim 1, wherein the second material of the second housing is selected from the group comprising synthetic resin, epoxy, silicone, rubber, acrylic, carbon fiber, and glass fiber.

9. A photoacoustic measuring device according to claim 8, characterized in that the second material of the second housing is flame-retardant or non-flammable.

10. A photoacoustic measuring device according to claim 1, wherein the second housing includes an opening open toward the first housing, and a cushioning material received in the opening is interposed between the ultrasonic sensor and the first housing.

11. A photoacoustic measuring device according to claim 1, characterized in that an intermediate layer made of a third material having a characteristic acoustic impedance is interposed between mutually opposing surfaces of the first housing and the second housing to be acoustically decoupled with respect to either or both of the first and second materials.

12. A photoacoustic measuring device according to claim 1, characterized in that the first housing and the second housing are mechanically connected.

13. The invention of claim 1 further comprises a case that encloses both the first housing and the second housing, and The above case is a photoacoustic measuring device characterized by exposing the light emitted from the light source to the irradiated sample and allowing the measuring surface of the ultrasonic sensor to acoustically contact the irradiated sample.

14. In any one of claims 1 to 13, A control unit that controls the operation of the light source and the ultrasonic sensor; and A photoacoustic measuring device characterized by further including an analysis unit that analyzes measurement data obtained from the ultrasonic sensor within the second housing.

15. In Claim 14, A photoacoustic measuring device characterized in that the above measurement data includes quantitative or qualitative information regarding the components of a specific substance within the above-mentioned sample.

16. A photoacoustic measuring device according to claim 14, characterized in that the measurement data includes information regarding the concentration of glucose in the dermal layer of the skin or in the blood vessels.

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