Biosensors, biosensor arrays, and devices

Abstract

A biosensor, a biosensor array, and a device are disclosed. The biosensor includes a light-emitting element, a light-detecting element, a light-transmitting layer under the light-emitting element and the light-detecting element, and an optical structure within the light-transmitting layer and configured to control the propagation direction of light.

Description

Technical Field

[0001] A biosensor, a biosensor array, and a device are disclosed. Background Art

[0002] Recently, research has been conducted on skin attachable devices for directly attaching to the skin or clothing to obtain biological information. Such skin attachable devices include biosensors for obtaining biological information. For example, a photoplethysmography (PPG) sensor can obtain a PPG signal from a user, and by analyzing the PPG signal, biological information such as the user's blood pressure, arrhythmia, heart rate, and / or oxygen saturation can be obtained. Summary of the Invention

[0003] Some example embodiments provide a biosensor having improved performance.

[0004] Some example embodiments provide a biosensor array including the biosensor.

[0005] Some example embodiments provide a device including the biosensor or the biosensor array.

[0006] According to some example embodiments, there is provided a biosensor including a light emitting element, a light detecting element, a light transmissive layer under the light emitting element and the light detecting element, and an optical structure within the light transmissive layer and configured to control a propagation direction of light.

[0007] The optical structure may control a propagation direction of light emitted from the light emitting element or a propagation direction of light reflected by a living body.

[0008] The optical structure may include a first optical structure disposed to overlap with the light emitting element in a thickness direction of the light transmissive layer.

[0009] The first optical structure may be configured to scatter or refract light emitted from the light emitting element.

[0010] The first optical structure may control light emitted at an angle greater than or equal to about 0 degrees and less than about 10 degrees with respect to a vertical direction of the light emitting element so that the light travels at an angle greater than or equal to about 10 degrees with respect to the vertical direction of the light emitting element, where the vertical direction of the light emitting element is perpendicular to an in-plane direction of the light emitting element.

[0011] The first optical structure may include a microlens or a microlens array.

[0012] An area of the microlens or the microlens array may be less than or equal to an area of the light emitting element.

[0013] A refractive index of a material constituting the first optical structure may be different from a refractive index of a material constituting the light transmissive layer.

[0014] The first optical structure may have a hole.

[0015] The first optical structure may be configured to reflect light emitted from the light-emitting element.

[0016] The first optical structure may be configured to reflect light emitted from the light-emitting element and cause the reflected light to travel at an angle less than about 60 degrees with respect to the vertical direction of the light-emitting element.

[0017] The first optical structure may have a cylindrical or frustoconical shape.

[0018] The first optical structure may include a metal.

[0019] The first optical structure may control the light emitted from the light-emitting element so that the light travels at an angle greater than or equal to about 10 degrees and less than about 60 degrees with respect to the vertical direction of the light-emitting element.

[0020] The optical structure may further include a second optical structure that is disposed to overlap with the light detection element in the thickness direction of the light-transmitting layer.

[0021] The optical structure may further include a third optical structure between the light-emitting element and the light detection element.

[0022] The third optical structure may be configured to scatter or refract the light reflected by the living body to direct the scattered light or refracted light to the light detection element.

[0023] The third optical structure may include a plurality of nanoparticles or a porous structure.

[0024] The optical structure may further include a second optical structure that is disposed to overlap with the light detection element in the thickness direction of the light-transmitting layer.

[0025] The light-transmitting layer may include a stretchable material.

[0026] The light-transmitting layer may include a plurality of first regions having a high elastic modulus and second regions having an elastic modulus lower than that of the first regions, the second regions being disposed between adjacent first regions, and each of the light-emitting element and the light detection element may be disposed on the first regions.

[0027] According to some example embodiments, there is provided a biosensor array including the biosensor.

[0028] The biosensor array may include a plurality of unit elements, and each unit element may include one or more light-emitting elements and one or more light detection elements.

[0029] Each unit element may further include a pressure sensor.

[0030] According to some example embodiments, a device including the biosensor or the biosensor array is provided.

[0031] The device may be a patch-type skin attachable device or a band-type skin attachable device.

[0032] The performance of the biosensor can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a top plan view showing an example of a biosensor according to some example embodiments,

[0034] Figure 2 is Figure 1 a cross-sectional view of the biosensor taken along line II-II,

[0035] Figure 3 is showing Figure 2 an enlarged schematic view of an example of a portion of the biosensor including a light emitting element,

[0036] Figure 4A and Figure 4B is showing Figure 3 an example of an optical structure in the biosensor,

[0037] Figure 5A and Figure 5B are schematic views respectively showing examples of the propagation directions of light when a first optical structure is absent and present in the biosensor of Figure 3 the biosensor,

[0038] Figure 6 is showing Figure 2 another example of an enlarged schematic view of a portion of the biosensor including a light emitting element,

[0039] Figure 7A and Figure 7B is showing Figure 6 an example of an optical structure in the biosensor,

[0040] Figure 8A and Figure 8B are schematic views respectively showing another example of the propagation directions of light when a first optical structure is absent and present in the biosensor of Figure 6 the biosensor,

[0041] Figure 9 is Figure 2 an enlarged schematic view of an example of the biosensor,

[0042] Figure 10A and Figure 10B are respectively showing when in Figure 9Schematic diagrams of examples of the propagation direction of light in a biosensor in the absence and presence of a third optical structure

[0043] Figure 11 Is a top plan view showing another example of a biosensor according to some example embodiments

[0044] Figure 12 Is Figure 11 A cross-sectional view of the biosensor taken along line XII-XII

[0045] Figure 13 Is a schematic diagram showing an example arrangement of a biosensor array according to some example embodiments

[0046] Figure 14 Is showing Figure 13 A schematic diagram of a part of the biosensor array

[0047] Figure 15 Is a schematic diagram showing another example arrangement of a biosensor array according to some example embodiments

[0048] Figure 16 Is showing Figure 15 A schematic diagram of a part of the biosensor array

[0049] Figure 17 Is a schematic diagram showing an example of a device according to some example embodiments

[0050] Figure 18 Is a graph showing the signal intensity of a biosensor according to the angle of incidence of light, and

[0051] Figure 19 Is a graph showing the change in the biological signal of a biosensor over time according to Example 2 and Comparative Example 2 Detailed implementation manners

[0052] In the following, example embodiments are described in detail so that those skilled in the art can easily implement them. However, the actual application structure can be implemented in various different forms and is not limited to the implementation manners described herein

[0053] In the drawings, for clarity, the thicknesses of layers, films, panels, regions, etc. are exaggerated. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or there can also be intervening elements. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements

[0054] In the following, a biosensor according to example embodiments is described

[0055] A biosensor is a sensor for detecting biological information through biological signals, such as a photoplethysmography (PPG) sensor, a blood pressure (BP) sensor, a blood glucose (BG) sensor, and / or a near-infrared brain imaging sensor, but not limited thereto. For example, the biosensor may be a photoplethysmography (PPG) sensor that detects changes in blood flow in blood vessels.

[0056] Figure 1 is a top plan view showing an example of a biosensor according to some example embodiments, Figure 2 is Figure 1 a cross-sectional view of the biosensor taken along line II-II.

[0057] Referring to Figure 1 and Figure 2 According to some example embodiments, the biosensor 100 includes a light-transmitting layer 110, a light-emitting element 120, a light-detecting element 130, and / or an optical structure 140.

[0058] The light-transmitting layer 110 may be disposed under the light-emitting element 120 and the light-detecting element 130 to support the light-emitting element 120 and the light-detecting element 130. The light-transmitting layer 110 may be, for example, a support substrate or may be formed on another support substrate (not shown). When including another support substrate, the support substrate may be a stretchable substrate.

[0059] The light-transmitting layer 110 may be configured to transmit light and may have, for example, a light transmittance of greater than or equal to about 70%, greater than or equal to about 75%, greater than or equal to about 80%, greater than or equal to about 85%, greater than or equal to about 90%, greater than or equal to about 95%, greater than or equal to about 97%, greater than or equal to about 98%, or greater than or equal to about 99%. The light-transmitting layer 110 may be disposed in the direction in which light is emitted from the light-emitting element 120 and in the direction in which light flows into the light-detecting element 130. For example, the light-transmitting layer 110 may be disposed closer to the living body (skin, blood vessels) to be detected by the light-emitting element 120 and the light-detecting element 130.

[0060] The light-transmitting layer 110 can be a stretchable layer, and thus can respond flexibly depending on an external force or external movement (such as twisting, pressing, or stretching), and can easily return to its initial state. The light-transmitting layer 110 can include a stretchable material such as an elastomer, and the stretchable material can include an organic elastomer, an organic / inorganic elastomer, an inorganic elastomer-like material, or a combination thereof. The organic elastomer or the organic / inorganic elastomer can be, for example, a substituted or unsubstituted polyorganosiloxane (such as polydimethylsiloxane), an elastomer including a substituted or unsubstituted butadiene moiety (such as styrene-ethylene-butene-styrene), an elastomer including a urethane moiety, an elastomer including an acrylic moiety, an elastomer including an olefin moiety, or a combination thereof, but is not limited thereto. The inorganic elastomer-like material can include an elastic ceramic, a solid metal, a liquid metal, or a combination thereof, but is not limited thereto.

[0061] The light-transmitting layer 110 can include regions having different stiffnesses, for example, a first region 110a having a relatively high stiffness and a second region 110b having a relatively low stiffness compared to the first region 110a. Here, the stiffness represents the degree of resistance to deformation when a force is applied from the outside. A relatively high stiffness means a relatively large resistance to deformation, such that the deformation is small, while a relatively low stiffness means a relatively small resistance to deformation, such that the deformation is large.

[0062] The stiffness can be evaluated from the elastic modulus, and a relatively high elastic modulus can mean a relatively high stiffness, and a relatively low elastic modulus can mean a relatively low stiffness. The elastic modulus can be, for example, the Young's modulus. The difference between the elastic moduli of the first region 110a and the second region 110b of the light-transmitting layer 110 can be about 100 times or greater, and the elastic modulus of the first region 110a can be about 100 times or greater than the elastic modulus of the second region 110b. Within the above range, the difference between the elastic moduli of the first region 110a and the second region 110b can be about 100 to 100,000 times, and the elastic modulus of the first region 110a can be about 100 times to about 100,000 times the elastic modulus of the second region 110b, but is not limited thereto. For example, the elastic modulus of the first region 110a can be about 10 7 Pa to about 10 12 Pa, and the elastic modulus of the second region 110b can be greater than or equal to about 10 2 Pa and less than about 10 7 Pa, but is not limited thereto.

[0063] The elongation rates of the first region 110a and the second region 110b of the light-transmitting layer 110 may be different due to the above-described difference in stiffness, and the elongation rate of the second region 110b may be higher than that of the first region 110a. Here, the elongation rate may be the percentage of the change in length increased to the break point with respect to the initial length. For example, the elongation rate of the first region 110a of the light-transmitting layer 110 may be less than or equal to about 5%, and within this range, it may be about 0% to about 5%, about 0% to about 4%, about 0% to about 3%, about 0% to about 2%, about 0% to about 1%, about 0.5% to about 5%, about 0.5% to about 4%, about 0.5% to about 3%, about 0.5% to about 2%, or about 1% to about 2%. For example, the elongation rate of the second region 110b of the light-transmitting layer 110 may be greater than or equal to about 10%, and within this range, it may be about 10% to about 300%, about 10% to about 200%, about 10% to about 100%, about 10% to about 90%, about 10% to about 80%, about 10% to about 70%, about 10% to about 60%, about 10% to about 50%, about 10% to about 40%, about 20% to about 70%, about 20% to about 60%, about 20% to about 50%, or about 20% to about 40%.

[0064] The plurality of first regions 110a of the light-transmitting layer 110 may have an island shape separated from each other, and the light-emitting element 120 and the light-detecting element 130 described later are respectively disposed on the corresponding first regions 110a of the light-transmitting layer 110.

[0065] The second region 110b of the light-transmitting layer 110 may be a region other than the plurality of first regions 110a and may be continuously connected throughout. The second region 110b of the light-transmitting layer 110 may be a region providing stretchability, and due to its relatively low stiffness and high elongation rate, it may flexibly respond to external forces or external movements (such as twisting, pressing, or stretching) and may easily return to its initial state.

[0066] For example, the first region 110a and the second region 110b of the light-transmitting layer 110 may have different shapes. For example, the first region 110a of the light-transmitting layer 110 may be flat, and the second region 110b may include a two-dimensional or three-dimensional stretchable structure. The two-dimensional or three-dimensional stretchable structure may have, for example, a wave shape, a fold shape, a pop-up shape, or a non-coplanar grid shape, but is not limited thereto.

[0067] For example, the first region 110a and the second region 110b of the light transmissive layer 110 may include different materials. For example, the first region 110a of the light transmissive layer 110 may include an inorganic material, an organic material, and / or an organic / inorganic material having a relatively high stiffness and a low elongation rate, and the second region 110b of the light transmissive layer 110 may include an inorganic material, an organic material, and / or an organic / inorganic material having a relatively low stiffness and a high elongation rate. For example, the first region 110a of the light transmissive layer 110 may include an organic material (such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polyamideimide, polyethersulfone, or a combination thereof), a carbon structure (such as diamond carbon), and the second region 110b of the light transmissive layer 110 may include: an organic elastomer or an organic / inorganic elastomer, such as a substituted or unsubstituted polysiloxane (such as polydimethylsiloxane), an elastomer including a substituted or unsubstituted butadiene moiety (such as styrene-ethylene-butene-styrene), an elastomer including a urethane moiety, an elastomer including an acrylic moiety, an elastomer including an olefin moiety, or a combination thereof; an inorganic elastomeric material, such as a ceramic, a solid metal, a liquid metal, or a combination thereof, but they are not limited thereto.

[0068] For example, the first region 110a and the second region 110b of the light transmissive layer 110 may be formed of the same material and may have different stiffnesses through different conditions such as the degree of polymerization and / or the degree of curing. For example, the light transmissive layer 110 may have a first region 110a having a relatively high stiffness and a second region 110b having a relatively low stiffness, and the first region 110a and the second region 110b are formed based on polydimethylsiloxane by changing the degree of polymerization, the type and content of the curing agent, and / or the curing temperature.

[0069] As described above, the light transmissive layer 110 includes a first region 110a having a relatively high stiffness and a low elongation rate and a second region 110b having a relatively low stiffness and a high elongation rate, and the light emitting element 120 and the light detecting element 130 are respectively disposed on the corresponding first region 110a of the light transmissive layer 110. Thus, even when a large external force or movement is applied to the light transmissive layer 110, the light emitting element 120 and the light detecting element 130 respectively disposed on the corresponding first region 110a of the light transmissive layer 110 receive relatively small strains. Therefore, damage or destruction of the light emitting element 120 and the light detecting element 130 due to excessive strain is reduced or prevented.

[0070] The light-emitting element 120 can be configured to emit light in a predetermined or alternatively desired wavelength region, and can include, for example, an inorganic light-emitting diode, an organic light-emitting diode, or a micro light-emitting diode. The light-emitting element 120 can include, for example, a pair of electrodes and a light-emitting layer disposed between the pair of electrodes. For example, one of the pair of electrodes can be a light-transmitting electrode, and the other can be a reflective electrode. For example, the electrode disposed close to the light-transmitting layer 110 can be the light-transmitting electrode. For example, the pair of electrodes can be stretchable electrodes, and the stretchable electrodes can include, for example, stretchable conductors, or can have a stretchable shape, such as a wavy shape, a wrinkled shape, a pop-up shape, or a non-planar grid shape. For example, the light-emitting layer can include an organic light-emitting material, quantum dots, and / or perovskite, but is not limited thereto. The light-emitting layer can be configured to emit light in one of the wavelength regions of the blue wavelength region, the green wavelength region, the red wavelength region, and the infrared wavelength region, for example, in one of the wavelength regions of the green wavelength region, the red wavelength region, and the infrared wavelength region, for example, in the green wavelength region. The pair of electrodes can be stretchable electrodes, and the light-emitting layer can be a stretchable light-emitting layer. Therefore, the light-emitting element 120 can be, for example, a stretchable element.

[0071] The light detection element 130 can be configured to absorb light in a predetermined or alternatively desired wavelength region, and can include, for example, an inorganic photodiode or an organic photoelectric conversion element. The light detection element 130 can include, for example, a pair of electrodes and a photoelectric conversion layer between the pair of electrodes. For example, one of the pair of electrodes can be a light-transmitting electrode, and the other can be a reflective electrode. For example, the electrode disposed close to the light-transmitting layer 110 can be the light-transmitting electrode. For example, the pair of electrodes can be stretchable electrodes, and the stretchable electrodes can include, for example, stretchable conductors, or can have a stretchable shape, such as a wavy shape, a wrinkled shape, a pop-up shape, or a non-planar grid shape. As an example, the photoelectric conversion layer can include, for example, an inorganic semiconductor, an organic semiconductor, and / or an organic / inorganic semiconductor, and can include, for example, a p-type semiconductor and an n-type semiconductor forming a pn junction. As an example, the photoelectric conversion layer can be a stretchable photoelectric conversion layer. The light detection element 130 can be, for example, a stretchable element.

[0072] The light emitted from the light-emitting element 120 can pass through the light-transmitting layer 110 and be reflected by a target part (hereinafter referred to as "target"), such as a blood vessel, of a living body, and the reflected light passes through the light-transmitting layer 110 again and can be absorbed in the light detection element 130 to obtain a biological signal.

[0073] The optical structure 140 can be disposed within the light-transmitting layer 110 and control the light propagation direction by, for example, scattering, refracting, and / or reflecting the light passing through the light-transmitting layer 110. The light whose propagation direction is controlled by the optical structure 140 can effectively reach the target (such as a blood vessel) or the light detection element 130.

[0074] For example, the optical structure 140 can control the propagation direction of the light emitted from the light-emitting element 120 such that the light can effectively reach the target. Thus, the light emitted from the light-emitting element 120 may not reach the target or pass through the target as it is, thereby reducing the lost light.

[0075] For example, the optical structure 140 can control the propagation direction of the light flowing into the light detection element 130. The light flowing into the light detection element 130 may be, for example, the light reflected by the target. Thus, the undetected and lost light caused by the fact that the light reflected by the target travels to an area other than the light detection element 130 can be reduced.

[0076] Referring to Figure 2 , the optical structure 140 may include a first optical structure 140a that overlaps with the light-emitting element 120 in the thickness direction (e.g., the Y direction) of the light-transmitting layer 110, a second optical structure 140b that overlaps with the light detection element 130 in the thickness direction (e.g., the Y direction) of the light-transmitting layer 110, and / or a third optical structure 140c disposed between the light-emitting element 120 and the light detection element 130, and at least one of them may be selected and included in the optical structure 140. In Figure 2 , the first optical structure 140a, the second optical structure 140b, and the third optical structure 140c are shown to have a predetermined or alternatively desired shape and size to illustrate the setting relationship with the light-emitting element 120 and the light detection element 130, but it is not limited thereto.

[0077] For example, the optical structure 140 can control the propagation direction of the light emitted from the light-emitting element 120 and emitted in a substantially perpendicular direction. This will be shown with reference to Figure 3 to FIG. 5.

[0078] Figure 3 is an enlarged schematic view showing an example of a part of a biosensor including a light-emitting element of Figure 2 , Figure 4A and Figure 4B is a schematic view showing an example of an optical structure in the biosensor of Figure 3 , Figure 5A and Figure 5B are schematic views respectively showing examples of the propagation directions of light when the first optical structure is absent and present in the biosensor of Figure 3 .

[0079] Referring to Figure 3, the first optical structure 140a overlaps with the light-emitting element 120 in the thickness direction (e.g., the Y direction) of the light-transmitting layer 110, and can be configured to scatter or refract light emitted in a direction substantially perpendicular to the in-plane direction (e.g., the X direction) of the light-emitting element 120, thereby changing the propagation direction of the light. For example, the first optical structure 140a can be configured to scatter or refract light emitted in a direction substantially perpendicular to the in-plane direction (e.g., the X direction) of the light-emitting element 120 so that it travels obliquely.

[0080] The first optical structure 140a can have a shape capable of causing such scattering or refraction. For example, the first optical structure 140a can include Figure 4A the hemispherical microlens shown or Figure 4B the microlens array shown. The diameter of the microlens can be several micrometers to several hundred micrometers, for example, greater than or equal to about 1 μm and less than about 1000 μm, about 1 μm to about 800 μm, about 10 μm to about 700 μm, about 20 μm to about 600 μm, or about 30 μm to about 500 μm, but is not limited thereto. For example, the microlens or microlens array can have an area smaller than or equal to the area of the light-emitting element 120. For example, compared with the area of the light-emitting element 120, it is about 0.1 times to about 1 times, about 0.2 times to 1 times, about 0.3 times to about 1 times, about 0.4 times to about 1 times, about 0.5 times to about 1 times, about 0.1 times to about 0.9 times, about 0.2 times to about 0.9 times, or about 0.3 times to about 0.9 times. Therefore, the propagation direction of the light incident substantially vertically from the light-emitting element 120 can be effectively changed.

[0081] The first optical structure 140a can include a material that causes such scattering or refraction, and the material of the first optical structure 140a can have a refractive index different from that of the material of the light-transmitting layer 110.

[0082] For example, the refractive index of the material of the first optical structure 140a can be higher than the refractive index of the material of the light-transmitting layer 110, for example, greater than or equal to about 0.1 or greater than or equal to about 0.2 higher than the refractive index of the material of the light-transmitting layer 110. For example, the first optical structure 140a can include an organic material, an inorganic material, an organic / inorganic material, or a combination thereof that satisfies this refractive index, such as an organic material, an inorganic material, or an organic / inorganic material, or a combination thereof having a relatively high refractive index greater than or equal to about 1.5, greater than or equal to about 1.6, greater than or equal to about 1.8, or greater than or equal to about 2.0. For example, the first optical structure 140a can be formed of a photosensitive polymer having a relatively high refractive index.

[0083] For example, the refractive index of the material forming the first optical structure 140a may be lower than the refractive index of the material forming the light-transmitting layer 110, for example, greater than or equal to about 0.1 or greater than or equal to about 0.2 lower than the refractive index of the material forming the light-transmitting layer 110. For example, the first optical structure 140a may include an organic material, an inorganic material, an organic / inorganic material, or a combination thereof that satisfies the refractive index. For example, the first optical structure 140a may include an organic material, an inorganic material, an organic / inorganic material, or a combination thereof having a refractive index less than about 1.4, less than or equal to about 1.3, less than or equal to about 1.2, or less than or equal to about 1.1, and may have pores including, for example, air having a refractive index of about 1.0.

[0084] As Figure 5A shown, when the first optical structure 140a is not present, the light emitted in a direction substantially perpendicular to the in-plane direction (e.g., the X direction) of the light-emitting element 120 may enter the skin A1 and the target A2 (such as a blood vessel) substantially perpendicularly. The perpendicularly incident light only passes through the target A2 (such as a blood vessel) and is not reflected but is lost in the living body. This light loss will reduce the efficiency of the biosensor.

[0085] Referring Figure 5B , the first optical structure 140a is disposed at a place where light is emitted from the light-emitting element 120. Therefore, the light emitted in the vertical direction (e.g., the Y direction) of the light-emitting element 120 can be passed through and scattered or refracted to change the propagation direction of the light emitted at a small angle of about 0° to about 10° with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120 to an angle (θ) greater than or equal to about 10° with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120, for example, greater than or equal to about 15°, greater than or equal to about 20°, greater than or equal to about 25°, about 10° to about 70°, about 10° to about 65°, about 10° to about 60°, greater than about 10° to less than about 60°, about 15° to about 70°, about 15° to about 65°, about 15° to about 60°, about 20° to about 70°, about 20° to about 65°, about 20° to about 60°, about 25° to about 70°, about 25° to about 65°, or about 25° to about 60°.

[0086] Therefore, the light having the propagation direction changed by the first optical structure 140a can flow into the skin A1 obliquely and be effectively reflected by the target A2 (such as a blood vessel), and the light that is not reflected but is lost in the living body as Figure 5A shown can be effectively reduced.

[0087] As another example, the optical structure 140 may control the propagation direction of the light emitted from the light-emitting element 120 that is emitted in a substantially parallel direction. This will be described with reference to Figure 6 FIGs. 7 to 8.

[0088] Figure 6 Another enlarged schematic view of a part including a light-emitting element of a biosensor shown Figure 2 is shown, Figure 7A and Figure 7B Another schematic view showing an example of an optical structure in a biosensor shown Figure 6 is shown, Figure 8A and Figure 8B are schematic views showing another example of the propagation directions of light when a first optical structure is absent and present, respectively, in a biosensor shown Figure 6 is shown.

[0089] Referring to Figure 6 , the first optical structure 140a overlaps with the light-emitting element 120 in the thickness direction (e.g., the Y direction) of the light-transmitting layer 110, and thus can be configured to reflect light emitted at an excessive angle with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120 and change the propagation direction of the light to a lower angle. For example, the first optical structure 140a can be configured to reflect light emitted at a high angle greater than or equal to about 70° with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120 to an angle less than about 60° with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120.

[0090] The first optical structure 140a can have a shape that causes such reflection. For example, the first optical structure 140a can have Figure 7A the cylindrical shape shown or Figure 7B the frustum of a cone shape shown. The diameter (e.g., the major axis) and height of the cylinder or frustum of a cone can be several micrometers to several hundred micrometers, respectively, such as greater than or equal to about 1 μm and less than about 1000 μm, about 1 μm to about 800 μm, about 10 μm to about 700 μm, about 20 μm to about 600 μm, or about 30 μm to about 500 μm, but are not limited thereto. The first optical structure 140a can be hollow inside. For example, the cylinder or frustum of a cone can have an area larger than the area of the light-emitting element 120, and thus can be effectively configured to reflect incident light at an excessive angle with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120.

[0091] The first optical structure 140a can include a material that causes such reflection, such as a metal. For example, the first optical structure 140a can be formed of a metal or coated with a metal on the surface.

[0092] As Figure 8AAs shown, when the first optical structure 140a is absent, light emitted at an excessive angle with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120 cannot reach a target A2 such as a blood vessel, but is lost in the skin A1 or the light-transmitting layer 110, or changes its propagation direction and flows into the light-detecting element 130. Such light may not contain biological information, thus reducing the efficiency of the biosensor 100.

[0093] Referring to Figure 8B , the first optical structure 140a is disposed where the light emitted from the light-emitting element 120 passes, and thus can be configured to reflect light emitted at a high angle greater than or equal to about 70° with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120, and change the propagation direction of the light to an angle with respect to the vertical direction (e.g., the Y direction) of the light-emitting element 120 that is: less than about 60°, less than or equal to about 55°, less than or equal to about 50°, less than or equal to about 45°, less than or equal to about 40°, greater than or equal to about 10° and less than about 60°, from about 10° to about 55°, from about 10° to about 50°, from about 10° to about 45°, from about 10° to about 40°, greater than or equal to about 15° and less than 60°, from about 15° to about 55°, from about 15° to about 50°, from about 15° to about 45°, from about 15° to about 40°, greater than or equal to about 20° and less than about 60°, from about 20° to about 55°, from about 20° to about 50°, from about 20° to about 45°, from about 20° to about 40°, greater than or equal to about 25° and less than about 60°, from about 25° to about 55°, from about 25° to about 50°, from about 25° to about 45°, or from about 25° to about 40°.

[0094] Therefore, the light with the changed propagation direction by the first optical structure 140a obliquely flows into the skin A1 and can be effectively reflected by a target A2 such as a blood vessel. Thus, the first optical structure 140a can effectively reduce the light that does not reach a target A2 such as a blood vessel but is lost or has no biological information, thus improving the efficiency of the biosensor 100.

[0095] As another example, the optical structure 140 can control the direction in which light (e.g., light reflected by the target A2) flows into the light-detecting element 130. This will be described with reference to Figure 9 and FIG. 10.

[0096] Figure 9 is Figure 2 an enlarged schematic view of an example of a biosensor, Figure 10A and Figure 10B are schematic views respectively showing examples of the propagation directions of light when the third optical structure is absent and present in the biosensor of Figure 9 .

[0097] Referring toFigure 9 , the third optical structure 140c is disposed between the light-emitting element 120 and the light-detecting element 130, and thus can be configured to scatter or refract light reflected by a target A2 such as a blood vessel, and thus guide the light in a predetermined or alternatively desired direction (for example, a direction in which the light flows into the light-detecting element 130). Therefore, even when the gap between the light-emitting element 120 and the light-detecting element 130 is large, the third optical structure 140c can reduce or prevent the light reflected by the target A2 from diffusing into other regions except the light-detecting element 130, and guide the light to flow precisely into the light-detecting element 130. As a result, the efficiency of the biosensor 100 is improved.

[0098] The third optical structure 140c may include a plurality of nanoparticles or a porous structure to guide light in a predetermined or alternatively desired direction. The plurality of nanoparticles may be, for example, inorganic particles, organic particles, organic / inorganic particles, or a combination thereof, such as metal particles, metal oxide particles, metal nitride particles, or a combination thereof. The porous structure may have a plurality of pores and may be a two-dimensional or three-dimensional structure. The particle size of each nanoparticle or the pore size in each porous structure may be several nanometers to several hundred nanometers, for example, greater than or equal to about 1 nm and less than about 1000 nm, about 1 nm to about 800 nm, about 3 nm to about 700 nm, about 5 nm to about 600 nm, or about 10 nm to about 500 nm, but is not limited thereto.

[0099] As Figure 10A shown, when the third optical structure 140c is absent, the light reflected by a target A2 such as a blood vessel may travel to other regions (for example, the region between the light-emitting element 120 and the light-detecting element 130) when it passes through the skin A1, thus reducing the efficiency of the biosensor 100.

[0100] Referring to Figure 10B , the third optical structure 140c is disposed where the light reflected by a target A2 such as a blood vessel passes, and thus can guide the light to continuously change direction when it passes through the plurality of nanoparticles or the porous structure, and finally flow into the light-detecting element 130. Therefore, the third optical structure 140c can reduce the loss of the reflected light with biological information and increase the intensity of the biological signal flowing into the light-detecting element 130, thus improving the efficiency of the biosensor 100.

[0101] For example, the optical structure 140 may include the aforementioned first optical structure 140a.

[0102] For example, in addition to the first optical structure 140a, the optical structure 140 may further include a second optical structure 140b that overlaps with the light detection element 130 in the thickness direction (e.g., the Y direction) of the light-transmitting layer 110. The second optical structure 140b is disposed below the light detection element 130, and thus can finely control the propagation direction of the light passing below the light detection element 130 among the light reflected by the target A2, reduce light loss, and increase the light inflow into the light detection element 130. Therefore, the efficiency of the biosensor 100 can be improved.

[0103] For example, the optical structure 140 may collectively include the aforementioned first optical structure 140a, second optical structure 140b, and third optical structure 140c.

[0104] For example, the optical structure 140 may include the aforementioned third optical structure 140c.

[0105] For example, in addition to the aforementioned third optical structure 140c, the optical structure 140 may further include a second optical structure 140b.

[0106] Hereinafter, a biosensor according to some example embodiments will be described.

[0107] Figure 11 is a top plan view showing another example of a biosensor according to some example embodiments, Figure 12 is Figure 11 a cross-sectional view of the biosensor taken along line XII-XII.

[0108] Referring to Figure 11 and Figure 12 , like the aforementioned example embodiments, the biosensor 100 according to some example embodiments includes a light-transmitting layer 110 having a first region 110a and a second region 110b, a light-emitting element 120, a light detection element 130, and / or an optical structure 140. A detailed description thereof is as described above.

[0109] However, different from the foregoing exemplary embodiments, a biosensor 100 according to some exemplary embodiments includes a plurality of light-emitting elements 120. The plurality of light-emitting elements 120 includes a first light-emitting element 120a and a second light-emitting element 120b that emit light in different wavelength regions. The first light-emitting element 120a and the second light-emitting element 120b can be used to detect objects having different absorption characteristics and / or reflection characteristics. For example, the first light-emitting element 120a can be a green light-emitting element that emits light in the green wavelength region, and the second light-emitting element 120b can be a red light-emitting element that emits light in the red wavelength region or an infrared light-emitting element that emits light in the infrared wavelength region. The green light-emitting element and the red / infrared light-emitting element can be used, for example, for the absorption characteristics and / or reflection characteristics of oxyhemoglobin (HbO2) and hemoglobin (Hb) in blood vessels.

[0110] The foregoing biosensor 100 can be applied in the form of an array arranged along rows and / or columns.

[0111] Figure 13 is a schematic diagram showing an exemplary arrangement of a biosensor array according to some exemplary embodiments, Figure 14 is showing Figure 13 a part of the biosensor array.

[0112] Referring to Figure 13 , the biosensor array 500 can have a matrix arrangement in which a plurality of unit elements 510 are repeatedly arranged along rows and / or columns. The arrangement of the unit elements 510 can be, for example, a Bayer matrix, a PenTile matrix, and / or a diamond matrix, but is not limited thereto.

[0113] In this drawing, all the unit elements 510 are shown to have the same size, but this is not limiting, and at least one of the unit elements 510 can be larger or smaller than the other unit elements 510. In this drawing, all the unit elements 510 are shown to have the same shape, but this is not limiting, and at least one of the unit elements 510 can have a shape different from the shapes of the other unit elements 510.

[0114] Each unit element 510 can be disposed on the foregoing light-transmissive layer 110 and includes a light-emitting element 120 and / or a light-detecting element 130. Figure 13 and Figure 14 show that each unit element 510 includes one first light-emitting element 120a, one second light-emitting element 120b, and two light-detecting elements 130, but this is not limiting, and can include at least one of the first light-emitting element 120a and the second light-emitting element 120b and at least one light-detecting element 130. Any one of the first light-emitting element 120a and the second light-emitting element 120b can be omitted.

[0115] The light-emitting element 120 and the light-detecting element 130 included in each unit element 510 may have dimensions (sizes) ranging from several micrometers to several hundred micrometers. For example, the light-emitting element 120 and the light-detecting element 130 included in each unit element 510 may independently have a width, length, and thickness greater than or equal to about 1 μm and less than about 1000 μm, and within this range, they may be about 10 μm to about 800 μm, about 10 μm to about 700 μm, about 10 μm to about 600 μm, or about 10 μm to about 500 μm.

[0116] This biosensor array 500 includes a plurality of light-emitting elements 120 and light-detecting elements 130 arranged along rows and / or columns, and thus can more easily detect biological signals.

[0117] Figure 15 is a schematic diagram showing an arrangement of another example of a biosensor array according to some example embodiments, Figure 16 is showing Figure 15 a schematic diagram of a part of the biosensor array.

[0118] The biosensor array 500 according to some example embodiments has a matrix arrangement as in the foregoing example embodiments, in which a plurality of unit elements 510 are repeatedly arranged along rows and / or columns, and each unit element 510 includes a light-emitting element 120 and a light-detecting element 130.

[0119] However, different from the foregoing example embodiments, the biosensor array 500 according to some example embodiments further includes a pressure sensor 300 in each unit element 510. That is, each unit element 510 includes a light-emitting element 120, a light-detecting element 130, and / or a pressure sensor 300. Figure 15 and Figure 16 shows an example in which each unit element 510 includes one first light-emitting element 120a, one second light-emitting element 120b, one light-detecting element 130, and / or one pressure sensor 300, but is not limited thereto, and may include at least one first light-emitting element 120a and at least one second light-emitting element 120b, at least one light-detecting element 130, and at least one pressure sensor 300. Any one of the first light-emitting element 120a and the second light-emitting element 120b may be omitted.

[0120] The pressure sensor 300 is a sensor that detects pressure changes. Therefore, among the plurality of pressure sensors 300 arranged in the biosensor array 500, the pressure sensor 300 can be used to indicate where the pressure occurs, so that the corresponding unit element 510 can be selectively operated individually to effectively detect biological signals at a specific position of a target such as a blood vessel.

[0121] For example, a method of operating a biosensor array 500 according to some example embodiments may include, for example, specifying where among the plurality of unit elements 510 of the biosensor array 500 a pressure sensor 300 that has detected pressure is located and selectively operating the unit element 510 to which the pressure sensor 300 belongs. The selective operation of the unit element 510 to which the pressure sensor 300 that has detected pressure belongs may include, for example, causing a light-emitting element 120 of the unit element 510 to which the pressure sensor 300 that has sensed pressure belongs to emit light, then receiving light reflected by a target (such as a blood vessel) from a light-detecting element 130 and converting it into an electrical signal.

[0122] The foregoing biosensor 100 or biosensor array 500 may be applied to various devices for collecting biological information, such as attachable devices such as wearable bioelectronic devices, skin-like devices, or smart clothing, to obtain biological signals temporarily or in real time, but is not limited thereto. The device may be, for example, a patch-type skin-attachable device or a band-type skin-attachable device.

[0123] Figure 17 is a schematic diagram showing an example of a device according to some example embodiments.

[0124] Referring to Figure 17 , a device 1000 according to some example embodiments may be a patch-type or band-type attachable biosensor device and include the foregoing biosensor 100 or biosensor array 500, an IC and / or a processor 600 for processing biological signals obtained from the biosensor 100 or biosensor array 500, and / or a display area 700 for displaying the obtained biological signals as various letters and / or images.

[0125] For example, the device may be a photoplethysmography (PPG) sensor device, an electroencephalogram (EEG) sensor device, an electrocardiogram (ECG) sensor device, a blood pressure (BP) sensor device, an electromyogram (EMG) sensor device, a blood glucose (BG) sensor device, an accelerometer device, an RFID antenna device, an inertial sensor device, an activity sensor device, a strain sensor device, a motion sensor device, or a combination thereof, but is not limited thereto.

[0126] Hereinafter, example embodiments will be described in more detail with reference to examples. However, these examples are exemplary, and the scope is not limited thereto.

[0127] Optical Simulation

[0128] Use the LightTools software to evaluate the signal intensity of the biosensor that depends on the incident angle of light emitted from the light-emitting element into a living body (skin, blood vessels, etc.). The incident angle is the angle with respect to the vertical direction (Y-axis, 0°) of the light-emitting element. The light-emitting element is based on a Lambert emitter and regards only the light signal reflected by blood vessels as a biological signal.

[0129] The structure of the biosensor is set as follows.

[0130] - Biosensor: PPG sensor

[0131] - Emission spectrum of the light-emitting element: 550 nm to 650 nm (λ max = 600 nm)

[0132] - Assume the internal quantum efficiency of the light detection element is 100%.

[0133] - Gap between the light-emitting element and the light detection element: 0 to 1 mm

[0134] - Substrate (light-transmitting layer) thickness: 0.05 mm

[0135] - Skin: Skin thickness 1.5 mm, blood vessel thickness 1 mm, fat thickness 2 mm, muscle thickness 30 mm

[0136] - Incident angle on the skin (blood vessels): 0 to 90 degrees

[0137] The results are shown in Figure 18 as follows.

[0138] Figure 18 is a graph showing the signal intensity of the biosensor according to the incident angle of light.

[0139] Referring to Figure 18 , the results show that the biosensor obtains a high biological signal with respect to incident light at a predetermined or alternatively desired angle (e.g., at an angle greater than or equal to about 10° and less than about 60°).

[0140] Example

[0141] Example 1

[0142] A styrene-ethylene-butene-styrene (SEBS) substrate with a thickness of 2 mm was prepared, and a Cu reflector in the shape of a frustum of a cone (major diameter: 3 mm) was inserted into the substrate. Subsequently, on the SEBS substrate, a light-emitting element (BioMon sensor, model: SFH7060, Osram Opto Semiconductors) was set at a place overlapping with the Cu reflector, and a light-detecting element (BioMon sensor, model: SFH7060, Osram Opto Semiconductors) was set at a place 4 mm away from the light-emitting element to fabricate a biosensor having Figure 8B the structure shown.

[0143] Example 2

[0144] A styrene-ethylene-butene-styrene (SEBS) substrate with a thickness of 1 mm was prepared, and a porous film (polyvinylidene fluoride (PVDF), reflectivity > 85%) was inserted into the substrate. Subsequently, on the SEBS substrate, a light-emitting element was set on one side, and a light-detecting element was set on the other side to be spaced 3 mm apart therefrom and the porous reflective film was placed therebetween, thereby fabricating a biosensor having Figure 9 the structure shown.

[0145] Comparative Example 1

[0146] A biosensor was fabricated according to the same method as in Example 1 except that no Cu reflector was used.

[0147] Comparative Example 2

[0148] A biosensor was fabricated according to the same method as in Example 2 except that no porous film was used.

[0149] Evaluation

[0150] The performance of the biosensors according to the examples and comparative examples was evaluated.

[0151] The performance of the biosensor was evaluated from the signal intensity and the signal-to-noise ratio (SNR).

[0152] The biosensor was attached around the radial artery of the wrist to obtain a biological signal (PPG signal) and the signal (frequency between 0.5 and 10 Hz) was distinguished from the noise (frequency: less than 0.5 Hz and greater than 10 Hz) by Fourier transform according to the equation SNR = signal / noise.

[0153] The biosensors according to Example 1 and Comparative Example 1 were worn and evaluated at the same position on the wrist, and the biosensors according to Example 2 and Comparative Example 2 were worn and evaluated at the same position on the wrist.

[0154] The results are shown in Table 1 and Figure 19 in.

[0155] Figure 19 It is a graph showing the change over time of the biological signal of the biosensor according to Example 2 and Comparative Example 2.

[0156] Table 1

[0157] SNR (dB) Example 1 15.7 Comparative Example 1 12.7 Example 2 21.2 Comparative Example 2 16.6

[0158] Referring to Table 1 and Figure 19 , the biosensor according to the example exhibits strong signal intensity and / or improved signal-to-noise ratio compared to the biosensor according to the comparative example.

[0159] Although the present disclosure has been described in connection with presently considered practical exemplary embodiments, it will be understood that the inventive concept is not limited to the disclosed exemplary embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0160] This application claims the priority and benefit of Korean Patent Application No. 10-2020-0068623, filed on Jun. 5, 2020, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

Claims

1. A biosensor, comprising a light-emitting element, a light-detecting element, a light-transmitting layer beneath the light-emitting element and the light-detecting element, and an optical structure within the light-transmitting layer, the optical structure configured to control a propagation direction of light, wherein the light-transmitting layer comprises a stretchable material, wherein the light-transmitting layer comprises a plurality of first regions having a relatively high elastic modulus and second regions having an elastic modulus lower than that of the first regions and located between adjacent first regions, each of the plurality of first regions has an island shape separated from each other, and each of the light-emitting element and the light-detecting element is on the first region of the light-transmitting layer.

2. The biosensor according to claim 1, wherein the optical structure is configured to control a propagation direction of light emitted from the light-emitting element or a propagation direction of light reflected by a living body.

3. The biosensor according to claim 1, wherein the optical structure comprises a first optical structure overlapping with the light-emitting element in a thickness direction of the light-transmitting layer.

4. The biosensor according to claim 3, wherein the first optical structure is configured to scatter or refract light emitted from the light-emitting element.

5. The biosensor according to claim 4, wherein the first optical structure is configured to control light emitted at an angle greater than or equal to 0 degree and less than 10 degrees with respect to a vertical direction of the light-emitting element to travel at an angle greater than or equal to 10 degrees with respect to the vertical direction of the light-emitting element, wherein the vertical direction of the light-emitting element is perpendicular to an in-plane direction of the light-emitting element.

6. The biosensor according to claim 4, wherein the first optical structure comprises a microlens or a microlens array.

7. The biosensor according to claim 6, wherein an area of the microlens or the microlens array is less than or equal to an area of the light-emitting element.

8. The biosensor according to claim 4, wherein a refractive index of a material constituting the first optical structure is different from a refractive index of a material constituting the light-transmitting layer.

9. The biosensor according to claim 4, wherein the first optical structure has holes.

10. The biosensor according to claim 3, wherein the first optical structure is configured to reflect light emitted from the light-emitting element.

11. The biosensor according to claim 10, wherein the first optical structure is configured to reflect light emitted from the light-emitting element and make the reflected light travel at an angle less than 60 degrees with respect to the vertical direction of the light-emitting element.

12. The biosensor according to claim 10, wherein the first optical structure has a cylindrical shape or a truncated cone shape.

13. The biosensor according to claim 10, wherein the first optical structure comprises a metal.

14. The biosensor according to claim 3, wherein the first optical structure is configured to control light emitted from the light-emitting element to travel at an angle greater than or equal to 10 degrees and less than 60 degrees with respect to the vertical direction of the light-emitting element.

15. The biosensor according to claim 3, wherein the optical structure further comprises a second optical structure which overlaps with the light detection element in the thickness direction of the light-transmitting layer.

16. The biosensor according to claim 3, wherein the optical structure further comprises a third optical structure between the light-emitting element and the light detection element.

17. The biosensor according to claim 1, wherein the optical structure further comprises a third optical structure between the light-emitting element and the light detection element.

18. The biosensor according to claim 17, wherein the third optical structure is configured to scatter or refract the light reflected by the living body to direct the scattered light or refracted light to the light detection element.

19. The biosensor according to claim 17, wherein the third optical structure comprises a plurality of nanoparticles or a porous structure.

20. The biosensor according to claim 17, wherein the optical structure further comprises a second optical structure which overlaps with the light detection element in the thickness direction of the light-transmitting layer.

21. A biosensor array comprising the biosensor according to claim 1.

22. The biosensor array according to claim 21, wherein the biosensor array comprises a plurality of unit elements, and each unit element of the plurality of unit elements comprises at least one of the light-emitting elements and at least one of the light detection elements.

23. The biosensor array according to claim 22, wherein each unit element further comprises a pressure sensor.

24. A device comprising the biosensor according to claim 1.

25. The device according to claim 24, wherein the device is a patch-type skin attachable device or a band-type skin attachable device.

26. A device comprising the biosensor array according to claim 21.

27. The device according to claim 26, wherein the device is a patch-type skin attachable device or a band-type skin attachable device.

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