JP6666191B2 - Measurement sensor package and measurement sensor - Google Patents

Description

  The present invention relates to a measurement sensor package and a measurement sensor.

  There is a need for a measurement sensor that can easily and rapidly measure biological information such as blood flow. For example, blood flow can be measured using the Doppler effect of light. When blood is irradiated with light, the light is scattered by blood cells such as red blood cells. The moving speed of the blood cell is calculated from the frequency of the irradiation light and the frequency of the scattered light.

  A measurement sensor for measuring blood flow is described in, for example, Patent Document 1 as a self-luminous measurement sensor, and an irradiation unit that irradiates light to blood and a light reception unit that receives scattered light are arranged on a substrate. A front plate having an entrance through which scattered light enters is adhered to the substrate by a light-shielding adhesive portion surrounding each of the substrates.

Japanese Patent No. 5031895

  When measuring the blood flow, for example, the tip of a finger, which is a measurement point, is brought into contact with the surface of the front plate to perform the measurement. A part of the light emitted from the irradiation unit is scattered by the skin of the finger before reaching the blood vessel under the skin. When the ratio of the scattered light from the skin in the light received by the light receiving unit increases, the ratio of the scattered light from the blood flow decreases, and it becomes difficult to measure the blood flow in a deep portion below the skin.

A plate-shaped base having a first surface, on which a plurality of dielectric layers are laminated, a plate-shaped lid having light transmittance and covering the first surface, and a metal thin layer; The base includes a first housing recess that houses a light emitting element and a second housing recess that houses a light receiving element having a light receiving unit, the first housing recess being located on the first surface. Has a first mounting portion on which the light receiving element is mounted, the second housing recess has a second mounting portion on which the light receiving element is mounted, and the lid includes an insulating material, The thin metal layer has an opposing surface opposing the first surface, the thin metal layer has an aperture that restricts light received by the light receiving element and is located on the opposing surface. In the direction connecting the center of gravity of the first mounting portion and the center of gravity of the second mounting portion, the diagram of the first mounting portion out of the center of the second mounting portion and the throttle hole. Is smaller than the distance between the centroid of the second mounting portion and the second edge of the throttle hole farthest from the centroid of the first mounting portion. The size of the aperture hole is larger than the size of the light receiving portion when viewed through a plane, and the light receiving portion is located in the aperture hole.

  According to another aspect of the present invention, there is provided a measurement sensor including the measurement sensor package described above and a light emitting element mounted on the first mounting portion of the first housing recess. A light-emitting element mounted so that the centroid of the portion matches the centroid of the first mounting portion, and a light-receiving element mounted on the second mounting portion of the second housing recess. And a light-receiving element mounted such that the centroid of the light-receiving unit is aligned with the centroid of the second mounting unit when viewed through a plane.

  According to the measurement sensor package of one embodiment of the present invention, it is possible to increase the ratio of the reflected light from the blood flow in the light received by the light receiving element.

  Further, according to the measurement sensor of one aspect of the present invention, by providing the measurement sensor package described above, it is possible to provide a measurement sensor capable of measuring a blood flow in a deep part below the skin.

FIG. 1 is a plan view showing a measurement sensor package 1 according to an embodiment of the present invention. It is sectional drawing cut | disconnected by the cutting surface line AA of FIG. It is sectional drawing cut | disconnected by the cutting surface line BB of FIG. FIG. 2 is a plan view of a measurement sensor package 1A corresponding to the plan view shown in FIG. 1. FIG. 2 is a cross-sectional view illustrating a configuration of the measurement sensor 100. FIG. 6 is a cross-sectional view of the measurement sensor 100A corresponding to the cross-sectional view shown in FIG. It is a figure showing the measurement result of the blood flow signal ratio in an example and a comparative example.

  FIG. 1 is a plan view showing a measurement sensor package 1 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along a cutting plane line AA in FIG. 1, and FIG. It is sectional drawing cut | disconnected by the cutting surface line BB. In the plan view of FIG. 1, the lid 3 is omitted.

  The measurement sensor package 1 includes a base 2, a lid 3, and a thin metal layer 4. The base 2 accommodates a light emitting element and a light receiving element, and includes a base body 20, a signal wiring conductor 23, and an external connection terminal 24.

  The base body 20 of the present embodiment has a rectangular plate shape, and is formed by laminating a plurality of dielectric layers. Further, at least two concave portions are provided in the base body 20, one of the two concave portions is a first housing concave portion 20a for housing the light emitting element, and the other of the two concave portions is The second housing recess 20b for housing the light receiving element. The first housing recess 20a and the second housing recess 20b are provided so as to open on the same main surface 21 (the first surface of the base 2) of the base body 20.

  The measurement sensor package 1 of the present embodiment is suitably used for a measurement sensor that measures a flow of a fluid such as a blood flow using the Doppler effect of light. In order to use the Doppler effect of light, the measurement sensor includes a light emitting element that irradiates the object with light and a light receiving element that receives light scattered by the object. In particular, when measuring blood flow, for example, irradiate light from the outside to a part of the body such as a finger, receive light scattered by blood cells contained in blood flowing through blood vessels under the skin, and perform frequency measurement. The blood flow is measured from the change. Therefore, in the measurement sensor package 1, the light emitting elements and the light receiving elements are arranged at predetermined intervals based on the positional relationship between the irradiation light and the scattered light. The first housing recess 20a and the second housing recess 20b are provided according to the positional relationship of the elements.

  The size of the first accommodating recess 20a and the size of the second accommodating recess 20b may be appropriately set according to the size of the light emitting element and the light receiving element to be accommodated. When a light emitting laser element (VCSEL) is used, the opening of the first housing recess 20a may be rectangular or square, for example. The length is 3 mm to 2.0 mm, the lateral length is 0.3 mm to 2.0 mm, and the depth is 0.3 mm to 1.0 mm. When a surface-incident photodiode is used as the light receiving element, the opening of the second housing recess 20b may have a rectangular or square shape, for example, and may have a vertical length, for example. Is 0.3 mm to 2.0 mm, the lateral length is 0.3 mm to 2.0 mm, and the depth is 0.4 mm to 1.5 mm.

  The opening shapes of the first housing recess 20a and the second housing recess 20b may be, for example, a circular shape, a square shape, a rectangular shape, or the like, or may be other shapes. The first housing recess 20a and the second housing recess 20b may have a uniform cross section parallel to the main surface of the base body 20 in the depth direction. As shown in the figure, at a predetermined depth, the cross-sectional shape is the same as the opening shape and is uniform, and after the predetermined depth, the cross-sectional shape is small and uniform to the bottom. There may be. In the case of a recess with a step as in this embodiment, a first mounting portion 20c for mounting a light emitting element is provided at the bottom of the first housing recess 20a, and a first mounting portion 20c is provided at the bottom of the second housing recess 20b. And a second mounting portion 20d for mounting the light receiving element. A connection pad 23a for electrically connecting the light emitting element or the light receiving element is provided on the surface of the step.

  The signal wiring conductor 23 is electrically connected to a light emitting element or a light receiving element, and transmits an electric signal input to the light emitting element and an electric signal output from the light receiving element. The signal wiring conductor 23 in the present embodiment includes a bonding wire that is a connection member that connects to the light emitting element or the light receiving element, a connection pad 23a to which the bonding wire is connected, and a connection pad that is electrically connected to the connection pad 23a. The signal via conductor 23b extends from directly below to the other main surface 22 of the base body 20, and an external connection terminal 24 electrically connected to the signal via conductor 23b. The external connection terminal 24 is provided on the other main surface 22 of the base body 20 and is electrically connected to a connection terminal of an external mounting board on which the measurement sensor including the measurement sensor package 1 is mounted and a terminal connection material such as solder. Connected.

  The external connection terminal 24 is formed of, for example, a nickel layer having a thickness of 0.5 to 10 μm and a gold layer having a thickness of 0.5 to 5 μm in order to improve wettability with a bonding material such as solder and improve corrosion resistance. The layers may be sequentially applied by a plating method.

  The base 2 is capable of accommodating a light emitting element and a light receiving element. If the base 2 is provided with a conductor such as the signal wiring conductor 23, the dielectric layer of the base body 20 is made of a ceramic insulating material, and the signal wiring conductor 23 is formed of a conductor. It may be a ceramic wiring board made of a material, or an organic wiring board whose dielectric layer is made of a resin insulating material.

  When the base 2 is a ceramic wiring board, each conductor is formed on a dielectric layer made of a ceramic material. The ceramic wiring board is formed from a plurality of ceramic dielectric layers.

  Examples of the ceramic material used in the ceramic wiring board include an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, a silicon nitride sintered body, and a glass ceramic sintered body. Condensation and the like can be mentioned.

  When the base 2 is an organic wiring board, a wiring conductor is formed on an insulating layer made of an organic material. The organic wiring board is formed from a plurality of organic dielectric layers.

  As the organic wiring board, for example, a printed wiring board, a build-up wiring board, a flexible wiring board or the like may be used as long as the dielectric layer is made of an organic material. Examples of the organic material used for the organic wiring board include an epoxy resin, a polyimide resin, a polyester resin, an acrylic resin, a phenol resin, and a fluorine-based resin.

The lid 3 covers one main surface (the first surface of the base 2) 21 of the base body 20 and is joined to the first surface 21 of the base 2 by the joining material 6. The first housing recess 20a and the second housing recess 20b in which the light emitting element and the light receiving element are housed are closed and sealed by the lid 3. The lid 3 is a plate-shaped member made of an insulating material, and transmits light emitted from the light emitting element housed in the first housing recess 20a and receives light received by the light receiving element housed in the second housing recess 20b. What is necessary is just to be comprised by the material which has light transmissivity which penetrates.

  In the measurement sensor provided with the measurement sensor package 1 of the present embodiment, the light emitted from the light emitting element is irradiated on the surface of the lid 3 with, for example, a finger as an object to be measured. When the lid 3 is made of a material having conductivity, when a finger is brought into contact with the lid 3, unnecessary electric charges accumulated in the fingers are released from the fingers, and the electric charges are transferred to the base 2 through the lid 3. Flows in and generates noise. By configuring the lid 3 with an insulating material, it is possible to prevent unnecessary charges from flowing through the lid 3.

  Further, the lid 3 needs to transmit irradiation light and scattered light to the object to be measured. Since the characteristics of the irradiation light and the scattered light are determined by the mounted light emitting element, it is sufficient that at least the light emitted from the mounted light emitting element is transmitted. The cover 3 may be made of an insulating material having a transmittance of 70% or more, preferably 90% or more of the light of the wavelength emitted from the light emitting element.

  As the insulating material constituting the lid 3, for example, a transparent ceramic material such as sapphire, a glass material, a resin material, or the like can be used. As the glass material, borosilicate glass, crystallized glass, quartz, soda glass, or the like can be used. As the resin material, a polycarbonate resin, an unsaturated polyester resin, an epoxy resin, or the like can be used.

  The lid 3 requires a predetermined strength because an object to be measured such as a finger is in direct contact therewith. The strength of the lid 3 depends on the strength of the constituent material and the plate thickness. As described above, if the material is a transparent ceramic material or a glass material, sufficient strength can be obtained by setting the thickness to a predetermined value or more. When a glass material is used as a constituent material of the lid 3, the thickness may be, for example, 0.05 mm to 5 mm.

  The thin metal layer 4 is disposed on the opposing surface 3 a of the lid 3, which is a main surface facing the one main surface 21 of the base body 20, that is, on the main surface on the opposite side to the main surface on which the finger contacts. This is a thin film layer made of a metallic material. The metal thin layer 4 is provided with an aperture 4a which is an opening through which light received by the light receiving element passes and which is an opening for restricting the passage of light.

  The aperture 4a is formed, when viewed through a plane, in a direction connecting the centroid of the first mounting portion 20c and the centroid of the second mounting portion 20d, with the centroid of the second mounting portion 20d and the aperture 4a. Between the centroid of the second mounting portion 20d and the first mounting portion 20c of the throttle hole 4a. It is smaller than the distance from the most distant second edge 4c.

  As shown in FIG. 1, the aperture 4a is an area defining the aperture 4a in a direction connecting the centroid of the first mounting portion 20c and the centroid of the second mounting portion 20d when viewed through a plane. It is sufficient that the centroid of the first placement unit 20c is away from the centroid of the first placement unit 20c with respect to the center of the second placement unit 20d. The area defining the aperture 4a may have a circular shape, an elliptical shape, an elliptical shape, a square shape, a triangular shape, or the like in plan perspective, or may have another shape.

In the measurement sensor provided with the measurement sensor package 1 of the present embodiment, the light emitted from the light emitting element is irradiated on the surface of the lid 3 with, for example, a finger as an object to be measured. At this time, the reflection from the skin tends to be reflected at a distance closer to the housing 3 than the reflection from the blood flow. Therefore, the reflected light traveling toward the region covering the second housing recess 20b is likely to enter a portion close to the first housing recess 20a.
According to the aperture hole 4a having the above-described configuration, it is possible to effectively block the reflected light from the skin, and to suppress the ratio of the reflected light from the skin to the light received by the light receiving element. According to the measurement sensor provided with the measurement sensor package 1 of the present embodiment, it is possible to increase the ratio of the reflected light from the blood flow, and it is possible to measure the blood flow in a deep part below the skin.

  The thin metal layer 4 secures the amount of light required for measurement while controlling the ratio of the scattered light from the skin in the light received by the light receiving element by appropriately adjusting the size of the aperture 4a. In addition, it is possible to reduce unnecessary light from entering the second housing recess 20b from the outside. When the light receiving element receives unnecessary light that enters from the outside, such as external light, the amount of unnecessary light received is added to the amount of light reflected by the object to be measured in the electric signal output from the light receiving element. As a result, optical noise is generated. The aperture 4a can reduce such optical noise.

  Further, the thin metal layer 4 also functions as an electromagnetic shield for suppressing an electromagnetic wave arriving from the outside from entering the second housing recess 20b. When the electromagnetic wave enters the second housing recess 20b, the signal wiring conductor 23, in particular, the bonding wire becomes an antenna and receives the entered electromagnetic wave, thereby causing electromagnetic noise. By providing a thin layer made of a metal material on the facing surface 3a of the lid 3 except for the aperture 4a, it is possible to suppress the entry of electromagnetic waves from the outside and reduce the generation of electromagnetic noise.

  By providing the thin metal layer 4 as described above, the influence of optical and electrical noise can be suppressed, and the measurement accuracy can be improved.

  For example, Cr, Ti, Al, Cu, Co, Ag, Au, Pd, Pt, Ru, Sn, Ta, Fe, and In are formed on the surface of the lid 3 made of a transparent ceramic material or a glass material. , Ni, W, and other metal materials and metal materials such as alloys thereof can be formed by vapor deposition, sputtering, baking, or the like. The thickness of the thin metal layer 4 is, for example, 500 ° to 4000 °.

  The measurement sensor package 1 of the present embodiment further includes a ground conductor layer 5 and a bonding material 6.

  The ground conductor layer 5 is a metallized layer provided on one main surface 21 of the base body 20 and is provided so as to surround the opening of the second housing recess 20b in which the light receiving element is housed. The outer shape of the ground conductor layer 5 may be, for example, rectangular so as to conform to the outer shape of the one main surface 21 of the base body 20, or may be other circular or polygonal shapes. In the present embodiment, the outer shape of the ground conductor layer 5 is rectangular. In addition, since the ground conductor layer 5 surrounds the opening of the second housing recess 20b, it is a metallized layer provided with a through hole having at least the same shape as or larger than the opening. In the present embodiment, the outer shape of the thin metal layer 4 and the outer shape of the ground conductor layer 5 have the same size.

  The ground conductor layer 5 is provided with a ground potential by being connected to, for example, a ground through conductor (ground via) (not shown) provided on the base 2. By providing the ground conductor layer 5 on one main surface 21 of the base body 20, the ground conductor layer 5 provided on the surface of the base 2 is electrically connected to the thin metal layer 4 by the conductive bonding material 6. . As a result, the thin metal layer 4 can be electrically grounded through the ground via, and the thin metal layer acts as an electrical shield from an externally charged body (especially a measurement object such as a finger), and the light receiving element 31 Noise contamination can be suppressed.

  The joining material 6 joins the base 2 and the lid 3. More specifically, one main surface 21 of the base body 20 and the opposing surface 3a of the lid 3 are joined at the outer peripheral portion. The bonding material 6 is provided in an annular shape along four sides of the one main surface 21 having a rectangular shape, and is used for ensuring airtightness and watertightness in the first housing recess 20a and the second housing recess 20b of the base 2. It is a sealing material.

  Each of the light emitting element and the light receiving element housed in the first housing recess 20a and the second housing recess 20b is weak to moisture or the like. Is provided.

  Further, the bonding material 6 has a light shielding property. Since the bonding material 6 has a light-shielding property, it is possible to prevent light from the outside from entering between the base 2 and the lid 3 and into the first housing recess 20a and the second housing recess 20b. .

  The light-shielding property of the bonding material 6 is preferably a light-shielding property by light absorption. From the viewpoint of preventing light from entering from the outside, the light may be shielded by reflection. However, there is a possibility that stray light generated inside the measurement sensor is reflected by the bonding material 6 and further received by the light receiving element. is there. If the bonding material 6 absorbs light, it can absorb light from the outside and prevent it from entering, and can also absorb stray light generated inside.

  The bonding material 6 is configured to include a material having such a light-shielding property by absorbing light. The bonding material 6 is obtained by dispersing a light-absorbing material in a resin-based adhesive such as an epoxy resin or a conductive silicon resin having a bonding property between the base 2 and the lid 3. As the light absorbing material, for example, an inorganic pigment can be used. Examples of the inorganic pigment include carbon pigments such as carbon black, nitride pigments such as titanium black, Cr—Fe—Co, Cu—Co—Mn, Fe—Co—Mn, and Fe—Co—Ni. -A metal oxide pigment such as a Cr pigment can be used.

  In the present embodiment, the thin metal layer 4 and the ground conductor layer 5 are respectively disposed in areas inside the annularly provided bonding material 6 in a plan view. That is, one main surface 21 of the base body 20 and the opposing surface 3a of the lid 3 are directly joined over the entire circumference by the joining material 6 without the thin metal layer 4 and the ground conductor layer 5 interposed therebetween.

  Since the thin metal layer 4 and the ground conductor layer 5 do not intervene in joining the base 2 and the lid 3, the bonding strength between the base 2 and the lid 3 can be increased, and peeling of the lid 3 can be prevented. can do.

  Next, another embodiment of the present invention will be described. FIG. 4 is a plan view of the measurement sensor package 1A corresponding to the plan view shown in FIG.

  The measurement sensor package 1A according to another embodiment is different from the measurement sensor package 1 according to the above-described embodiment in that when viewed through a plane, the centroid of the first mounting portion 20c and the first edge of the aperture 4a are formed. The distance from the portion 4b is larger than the distance between the centroid of the first mounting portion 20c and the centroid of the second mounting portion 20d, and the other configuration is the same. Are given the same reference numerals as those of the measurement sensor package 1, and detailed description is omitted.

In the measurement sensor including the measurement sensor package 1A according to another embodiment, the reflection reflected by the skin and incident on a portion of the cover 3 that is close to the first housing recess 20a in the area covering the second housing recess 20b. Light can be more effectively shielded. Therefore, according to the measurement sensor provided with the measurement sensor package 1A, the ratio of the reflected light from the blood flow can be further increased, and the blood flow in a deep part under the skin can be measured with high accuracy. . Furthermore, according to the measurement sensor provided with the measurement sensor package 1A, the object to be measured is not limited to the finger of a human, but measures a blood flow in a deep part in another part of the human body, for example, an arterial blood flow. It becomes possible. Further, according to the measurement sensor provided with the measurement sensor package 1A, for example, it is possible to measure the blood flow of a large animal such as a cow in a place where the skin is thicker than a human and blood vessels are deep.

A method for manufacturing the measurement sensor packages 1 and 1A will be described. First, the base 2 is manufactured in the same manner as a known method for manufacturing a multilayer wiring board. When the base 2 is a ceramic wiring board and the ceramic material is alumina, first, a suitable raw material powder such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), and magnesia (MgO) is used. An organic solvent and a solvent are added and mixed to form a slurry, which is formed into a sheet by a well-known doctor blade method, calender roll method, or the like, to obtain a ceramic green sheet (hereinafter, also referred to as a green sheet). Thereafter, the green sheet is punched into a predetermined shape, and an organic solvent and a solvent are added to and mixed with raw material powder such as tungsten (W) and a glass material to form a metal paste, which is printed on the surface of the green sheet by a printing method such as screen printing. To print the pattern. In the via conductor, a through hole is provided in the green sheet, and a metal paste is filled in the through hole by screen printing or the like. The metallized layer serving as the ground conductor layer 5 is formed on the outermost surface with a metal paste. A plurality of the green sheets thus obtained are laminated, and the green sheets are simultaneously fired at a temperature of about 1600 ° C., whereby the base 2 is manufactured.

  On the other hand, a lid 3 is prepared by cutting a glass material into a predetermined shape by cutting, cutting, or the like, and a thin metal layer 4 is formed on the facing surface 3a by vapor deposition, sputtering, baking, or the like. At this time, the aperture 4a can be formed by patterning the metal thin film by photolithography (wet etching), dry etching, or the like.

  Next, measurement sensors 100 and 100A according to another embodiment of the present invention will be described.

  FIG. 5 is a cross-sectional view illustrating the configuration of the measurement sensor 100. The measurement sensor 100 includes the measurement sensor package 1, the light emitting element 30 housed in the first housing recess 20a, and the second housing recess 20b. And a light receiving element 31 housed therein. FIG. 6 is a cross-sectional view illustrating the configuration of the measurement sensor 100A. The measurement sensor 100A includes the measurement sensor package 1A, the light emitting element 30 housed in the first housing recess 20a, and the second housing recess 20b. And a light receiving element 31 housed therein. In the measurement sensors 100 and 100A of FIGS. 5 and 6, the light-emitting element 30 has a first light-emitting element such that the centroid of the light-emitting portion coincides with the centroid of the first mounting portion 20c of the first accommodation recess 20a in a plan view. The light receiving element 31 is mounted on the mounting portion 20c, and is placed on the second mounting portion 20d such that the centroid of the light receiving portion matches the centroid of the second mounting portion 20d of the second housing recess 20b. Is done.

  The measurement sensor 100 may be configured such that the first edge 4b of the aperture 4a overlaps the light receiving portion of the light receiving element 31 when seen through the plane. According to such a configuration, the light reflected from the skin is effectively shielded, whereby the ratio of the light reflected from the skin to the light received by the light receiving element 31 is suppressed, and the reflection from the blood flow is suppressed. Since it becomes possible to increase the ratio of light, it becomes possible to measure the blood flow in a deep part under the skin.

  As shown in FIG. 4, the measurement sensor package 1A included in the measurement sensor 100A has a distance between the centroid of the first mounting portion 20c and the first edge 4b of the aperture 4a when viewed through a plane. The distance between the centroid of the first mounting portion 20c and the centroid of the second mounting portion 20d is configured to be larger. In other words, in the measurement sensor 100A, when viewed in a plan view, the first edge 4b of the aperture 4a is formed in the direction connecting the centroid of the light emitting unit of the light emitting element 30 and the centroid of the light receiving unit of the light receiving element 31. The center of the light receiving unit of the light receiving element 31 is shifted in a direction away from the center of the light emitting unit of the light emitting element 30. Therefore, according to the measurement sensor 100A, the ratio of the reflected light from the blood flow in the light received by the light receiving element 31 can be increased, and the blood flow in a deep portion below the skin can be measured.

  In the measurement sensors 100 and 100A, the light emitting element 30 and the light receiving element 31 are mounted on the measurement sensor packages 1 and 1A, and are connected to the connection pads 23a with the bonding wires 32. 20.

  The light emitting element 30 can use a semiconductor laser element such as a VCSEL, and the light receiving element 31 can use various photodiodes such as a silicon photodiode, a GaAs photodiode, an InGaAs photodiode, and a germanium photodiode. The light emitting element 30 and the light receiving element 31 may be appropriately selected depending on the type of the object to be measured, the type of the parameter to be measured, and the like.

  When measuring the blood flow, for example, in order to perform measurement using the Doppler effect of light, any VCSEL that is the light emitting element 30 may emit laser light having a wavelength of 850 nm. When performing other measurements, the light-emitting element 30 that emits laser light having a wavelength according to the measurement purpose may be selected. The light receiving element 31 only needs to be able to receive the light emitted from the light emitting element 30 when the wavelength of the received light does not change from the laser light emitted from the light emitting element 30. What is necessary is just to be able to receive the light of the wavelength.

  In the present embodiment, the light emitting element 30 and the light receiving element 31 are electrically connected to the connection pad 23a by, for example, a bonding wire 32. However, flip chip connection, bump connection, connection using an anisotropic conductive film, or the like is used. Other connection methods may be used.

  The measurement sensors 100 and 100A are used by being mounted on an external mounting board. On the external mounting board, for example, a control element for controlling light emission of the light emitting element 30, an arithmetic element for calculating a blood flow velocity or the like from an output signal of the light receiving element 31, and the like are also mounted.

  When measuring, a light emitting element control current is input to the measurement sensors 100 and 100A from the external mounting board via the external connection terminals 24 in a state where the fingertip of the finger as the object to be measured is in contact with the surface of the lid 3. The light is input to the light emitting element 30 through the signal via conductor 23b and the connection pad 23a, and the light for measurement is emitted from the light emitting element 30. When the emitted light passes through the lid 3 and irradiates the fingertip, it is scattered by blood cells in blood. When the scattered light transmitted through the lid 3 and passed through the aperture 4 a is received by the light receiving element 31, an electric signal corresponding to the amount of received light is output from the light receiving element 31. The output signal passes through the connection pad 23a and the signal via conductor 23b, and is output from the measurement sensors 100 and 100A to the external mounting board via the external connection terminal 24.

  In the external mounting board, the signals output from the measurement sensors 100 and 100A are input to the arithmetic element, and for example, the blood flow velocity is calculated by analyzing the intensity of the scattered light received by the light receiving element 31 for each frequency. be able to.

  In the above description, the signal via conductors 23b are formed in a straight line in the vertical direction in the base body 20. However, the signal via conductors 23b are electrically connected from the one main surface 21 of the base body 20 to the external connection terminals 24 on the other main surface 22. As long as they are electrically connected, they may be formed not in a straight line but in the base body 20 so as to be shifted by an inner layer wiring, an inner ground conductor layer, or the like.

  Further, the base 2 may be provided with a ground via conductor penetrating the base body 20 in the thickness direction. The ground via conductor is electrically connected to, for example, the ground conductor layer 5 and the external connection terminal 24, and is disposed outside the first housing recess 20a and the second housing recess 20b of the base body 20. The ground via conductor guides an electric charge released when a finger of a person to be measured contacts a measurement sensor from one main surface 21 of the base body 20 to the other main surface 22 of the base body 20. , Release to the outside.

  By forming a path in which the charge discharged from a person easily flows in the measurement sensor package 1 and 1A, the charge is guided to this path to escape the charge to the outside, thereby preventing generation of electrical noise. ing.

  The measurement sensor package having the same configuration as the measurement sensor package 1 shown in FIGS. 1 to 3 and the measurement sensor package having the same configuration as the measurement sensor package 1A shown in FIG. A VCSEL having a near-infrared wavelength as the light emitting element 30 is mounted on the sensor package so that the centroid of the light emitting section matches the centroid of the first mounting section 20c. As the light receiving element 31, the diameter of the light receiving section is 200 μm. A certain silicon photodiode was mounted so that the centroid of the light receiving portion coincided with the centroid of the second mounting portion 20d to obtain a measurement sensor according to an embodiment of the present invention.

  The distance between the center of the light emitting unit of the light emitting element 30 and the center of the light receiving unit of the light receiving element 31 was 1.2 mm. Alumina was used as the material of the base 2 of the measurement sensor package 1, and borosilicate glass was used for the lid 3. The aperture 4a in the thin metal layer 4 formed on the lid 3 was formed in a circular shape and the hole diameter was 0.3 mm.

  In the measurement sensor according to the embodiment, when viewed in a plan view, in the direction connecting the centroid of the first mounting portion 20c and the centroid of the second mounting portion 20d, the centroid of the region defining the aperture 4a and the second centroid are shown. The amount of deviation from the centroid of the two mounting portions 20d was set to 0.022 mm and 0.075 mm. In defining the amount of deviation, the centroid of the second mounting portion 20d was set as the origin of the amount of deviation, and the direction away from the centroid of the first mounting portion 20c was defined as the positive direction of the amount of deviation.

  A measurement sensor of a comparative example was obtained in the same manner as in the example except that the amount of displacement was different. The shift amounts in the comparative example were -0.015 mm, -0.034 mm, and -0.081 mm. In the measurement sensor of the comparative example, when viewed through the plane, the centroid of the area defining the aperture 4a is closer to the centroid of the first mounting portion 20c with respect to the centroid of the second mounting portion 20d. It is shifted in the direction.

  In each of the measurement sensors of the example and the comparative example, as a simulated skin, a silicon plate having a thickness of 0.3 mm and a light transmittance of 80% with respect to light emitted from the light emitting element was moved 1.0 mm from the measurement sensor. A scatter plate made of particles having a thickness of 2.0 mm and a particle diameter of 7 μm is placed at a position separated by 0.5 mm upward from the simulated skin as a simulated blood flow. In this state, the first output signal from the measurement sensor, which was generated by the reflected light from the simulated skin and the simulated blood flow, was measured.

  Next, the second output signal of the measurement sensor, which is generated by the reflected light from the simulated skin, is measured in the same manner as the measurement of the first output signal except that the simulated blood flow is removed. The blood flow signal ratio was calculated based on the difference from the second output signal.

  FIG. 7 is a diagram illustrating measurement results of the blood flow signal ratios of the example and the comparative example. In FIG. 7, the result corresponding to the shift amount of 0.022 mm and the result corresponding to the shift amount of 0.075 mm are the measurement results of the example, and the others are the measurement results of the comparative example.

  As in the embodiment, if the centroid of the area defining the aperture 4a is shifted in the direction away from the centroid of the first mounting portion 20c with respect to the centroid of the second mounting portion 20d, It was found that the flow signal ratio increased.

DESCRIPTION OF SYMBOLS 1, 1A Measurement sensor package 2 Base 3 Lid 3a Opposing surface 4 Thin metal layer 4a Restricted hole 4b First edge 4c Second edge 5 Ground conductor layer 6 Bonding material 20 Base body 20a First housing recess 20b Second Housing recess 20c First mounting portion 20d Second mounting portion 21 One main surface (first surface)
22 other main surface 23 signal wiring conductor 23a connection pad 23b signal via conductor 24 external connection terminal 30 light emitting element 31 light receiving element 32 bonding wire 100, 100A measurement sensor

Claims (5)

A plate-shaped substrate having a first surface, on which a plurality of dielectric layers are laminated;
A plate-shaped lid having a light transmitting property and covering the first surface;
And a thin metal layer,
The substrate is
A light receiving element having a first receiving recess for receiving a light emitting element and a light receiving part, which is located on the first surface.
And a second housing recess for housing
The first housing recess is
A first mounting portion on which the light emitting element is mounted,
The second housing recess,
A second mounting portion on which the light receiving element is mounted,
The lid,
Including an insulating material, having an opposing surface opposing the first surface,
The thin metal layer,
Located on the opposite surface,
Having an aperture that regulates light received by the light receiving element,
When viewed in a plan view, in a direction connecting the centroid of the first mounting portion and the centroid of the second mounting portion.
And the center of gravity of the second mounting portion and the aperture hole closest to the center of gravity of the first mounting portion among the apertures.
The distance from the first edge to the centroid of the second mounting portion and the centroid of the first mounting portion in the aperture hole
Smaller than the distance to the second edge farthest from the
When viewed through a plane, the size of the aperture is larger than the size of the light receiving unit.
A measuring sensor package, wherein the light receiving portion is located in the aperture.   When viewed through a plane, the distance between the centroid of the first mounting portion and the first edge of the aperture hole is the distance between the centroid of the first mounting portion and the second mounting portion. The package for a measurement sensor according to claim 1, wherein the distance is larger than a distance from a center of gravity.   The measurement sensor package according to claim 1, wherein the aperture has a circular, elliptical, or elliptical shape when viewed through a plane. A measurement sensor package according to any one of claims 1 to 3,
A light-emitting element mounted on the first mounting portion of the first housing recess, the mounting being performed such that the center of the light-emitting portion coincides with the centroid of the first mounting portion in a plan view. A light emitting element to be placed;
A light receiving element mounted on the second mounting portion of the second housing recess, the mounting being performed such that the centroid of the light receiving portion matches the centroid of the second mounting portion when seen through a plane. A light receiving element to be placed.   The measurement sensor according to claim 4, wherein the first edge of the aperture hole overlaps the light receiving portion when viewed through a plane.

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