JP2010200970A - Optical sensor and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sensor effectively receiving weak nonelastic scattered light and a method for manufacturing the optical sensor. <P>SOLUTION: The optical sensor is provided with a light emitting element 16 for emitting light, a light receiving element 17 for receiving interference light of nonelastic scattered light which is light from the light emitting element 16 scattered by a subject 100 and elastic scattered light, arranged on the same substrate 11 face where an electric wiring pattern is formed; includes a light blocking wall 18 arranged on the substrate 11 face so as to surround the light receiving element 17 and having an incident window for causing the interference scattered light to enter the light receiving face of the light receiving element 17; the light emitting element 16, the light blocking wall 18, and the light receiving element 17 are arranged so as to be adjacent to each other in the order. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical sensor and a method of manufacturing the same, and more particularly to an optical sensor that measures information such as a flow rate and a flow rate of the fluid using inelastic scattered light from a minute scatterer in the fluid.

  With the aging of society, there is an increasing interest in managing health to prevent lifestyle-related diseases. Developed a biological information measuring device that measures biological information such as blood flow using an optical sensor in order to quickly and easily discover lifestyle-related diseases such as cerebral thrombosis and myocardial infarction that occur due to poor blood flow (For example, refer to Patent Documents 1 and 2).

  7 and 8 show an example of a conventional optical sensor mounted on the biological information measuring device. FIG. 7 is a schematic configuration diagram of a conventional optical sensor. FIG. 8 is a bird's-eye view of a conventional optical sensor. Electric wiring patterns 102, 103, 104, and 105 are formed on the surface of the substrate 11. The electric wiring pattern 102 is connected to the anode of the light receiving element 17, and the electric wiring pattern 103 is connected to the cathode of the light receiving element 17. The electrical wiring pattern 102 is connected to an amplifier (not shown) for detecting a minute signal. The electrical wiring pattern 105 is connected to the anode of the light emitting element 16, and the electrical wiring pattern 104 is connected to the cathode of the light emitting element 16. The electrical wiring pattern 105 is connected to the drive circuit of the light emitting element 16.

  The light emitting element 16 is mounted on the electric wiring pattern 104 via a solder film (not shown). There are electrodes on the light emitting element 16, and the electrodes are connected to the electric wiring pattern 105 by wire bonding. Current from the drive circuit of the light emitting element 16 is injected into the light emitting element 16 from the electrode. The light receiving element 17 is mounted on the electric wiring pattern 103 via a solder film (not shown). There are electrodes on the light receiving element 17, and the electrodes are connected to the electric wiring pattern 102 by wire bonding.

  A Doppler shift method will be described as an example of a biological information measurement method using the optical sensor 101. In this case, the subject is a living body, and the measurement target is red blood cells that are moving in capillaries. When current is injected into the light emitting element 16 from the electric wiring pattern 105, the light emitting element 16 oscillates and light is emitted from the light emitting element 16. The light emitted from the light emitting element 16 is irradiated on the living body surface outside the optical sensor 101, and inelastically scattered light scattered by the red blood cells to be measured is generated. In addition, elastic scattered light is generated from a stationary biological tissue. The inelastic scattered light and the elastic scattered light interfere with each other, and the biological information is measured by receiving the interference light with the light receiving element 17.

  Here, when the optical sensor 101 is brought close to the measurement target, the light from the light emitting element 16 is scattered even in a living tissue that is stationary. Therefore, the scattered light received by the light receiving element 17 includes elastic scattered light from a stationary biological tissue such as a stratum corneum and inelastic scattered light from red blood cells to be measured. The frequency of inelastically scattered light is Doppler shifted according to the blood flow, causing interference with elastically scattered light by a stationary biological tissue. By detecting this interference light by homodyne detection, biological information such as blood flow volume, blood volume, blood flow velocity, and pulse can be measured.

  Here, when the measurement target is red blood cells in a capillary of a living body, the inelastic scattered light received by the light receiving element 17 is very weak, about several hundred pW. For this reason, when light directly enters the light receiving element 17 from the light emitting element 16, the SN ratio of the output signal from the light receiving element 17 is deteriorated, and the contribution of inelastically scattered light is buried in noise. Can not. Therefore, a light shielding wall 108 for avoiding direct light from the light emitting element 16 to the light receiving element 17 is provided on the surface of the substrate 11.

JP 2002-330936 A JP 2004-229920 A JP 2007-175415 A JP 2008-010832 A JP 2008-145168

M.M. D. Stern: In vivo evaluation of microcirculation by coherent light scattering, Nature, Vol. 254, pp. 56-58 (1975)

  However, in the conventional optical sensor, the distance between the light emitting element and the light receiving element and the distance between the light emitting element and the subject are not considered. Further, sufficient consideration has not been given to the shape of the light shielding wall.

  Therefore, an object of the present invention is to provide an optical sensor capable of efficiently receiving weak inelastic scattered light and a method for manufacturing the optical sensor.

  In order to achieve the above object, the inventors have found through experiments an arrangement of a light-emitting element, a light-receiving element, and a light-shielding wall so that weak inelastic scattered light can be accurately measured.

  Specifically, the optical sensor of the present invention includes a light emitting element that emits light, inelastically scattered light scattered by a measurement target in which light from the light emitting element moves inside the subject, and stationary inside the subject. An optical sensor disposed on the same substrate surface on which an electrical wiring pattern is formed, and receiving the interference light of the elastically scattered light scattered from the target, so as to surround the light receiving element The light-emitting element, the light-shielding wall, and the light-receiving element are arranged adjacent to each other in order. It is characterized by that.

Since the light emitting element, the light shielding wall, and the light receiving element are arranged adjacent to each other in order, the light emitting element and the light receiving element can be brought closest to each other. Thereby, the weak inelastic scattered light from a measuring object can be received efficiently.
Further, since the light shielding wall shields the direct light from the light emitting element, the light emitting element and the light receiving element can be provided on the same substrate surface. Thereby, manufacture of an optical sensor becomes easy.

  In the optical sensor of the present invention, the distance between the light emitting element and the subject is preferably 1.3 mm or more and 2.8 mm or less.

  In the optical sensor of the present invention, the distance between the light emitting element and the light receiving element on the substrate surface is preferably 500 μm or less.

In the optical sensor of the present invention, it is preferable that the projected shape of the light shielding wall on the substrate surface is a shape to be rotated.
According to the present invention, the manufacture of the light shielding wall is facilitated and the light shielding wall can be easily mounted on the substrate surface. Therefore, the manufacture of the optical sensor is facilitated.

In the optical sensor of the present invention, the light shielding wall is preferably made of a non-conductive material.
According to the present invention. Generation of noise due to the proximity of the light emitting element and the light receiving element can be prevented.
Further, when the entrance window of the light shielding wall is brought into close contact with the surface of the subject, it is possible to prevent the occurrence of noise due to static electricity of the subject.

  In the optical sensor of the present invention, the distance between the light emitting element and the light receiving element on the substrate surface is preferably about 500 μm.

  In the optical sensor of the present invention, the distance between the substrate surface and the subject is preferably approximately 2.0 mm.

In the optical sensor of the present invention, the light shielding wall has a cylindrical shape, one of the cylindrical openings is fixed to the substrate surface, and the other of the cylindrical openings is the incident window. Is preferred.
According to the present invention, the manufacture of the light shielding wall is facilitated and the light shielding wall can be easily mounted on the substrate surface. Therefore, the manufacture of the optical sensor is facilitated.
In addition, since the entire entrance window of the light shielding wall is easily brought into close contact with the subject surface, it is possible to easily prevent external light from entering the light shielding wall.

In the optical sensor according to the present invention, it is preferable that the light shielding wall has a cap shape that three-dimensionally covers the light receiving element, and an area of the incident window is smaller than an area on the substrate surface.
Since the inside surrounded by the light shielding wall extends with respect to the incident window, inelastically scattered light scattered at a large scattering angle can be received by the light receiving element. In addition, since the area of the incident window is small, it is possible to efficiently prevent external light from entering the light shielding wall. Accordingly, inelastically scattered light can be received efficiently.

  In order to achieve the above object, an optical sensor manufacturing method of the present invention is an optical sensor manufacturing method of the present invention, in which the light emitting element, the light shielding wall, and the light receiving element are arranged adjacently in order. It has the process.

  Since the light shielding wall blocks direct light from the light emitting element, the light emitting element and the light receiving element can be provided on the same substrate surface. Thereby, manufacture of an optical sensor becomes easy. In addition, since the light emitting element, the light shielding wall, and the light receiving element are arranged adjacent to each other in order, it is possible to efficiently receive weak inelastic scattered light from the measurement target. Therefore, according to the present invention, it is possible to easily manufacture an optical sensor that can efficiently receive weak inelastic scattered light from a measurement object.

  The above inventions can be combined as much as possible.

  According to the present invention, since the light-emitting element, the light-shielding wall, and the light-receiving element are sequentially arranged adjacent to each other, it is possible to provide an optical sensor that can accurately measure weak inelastic scattered light and a method for manufacturing the optical sensor. it can.

It is a schematic block diagram of the biological information measuring device carrying the optical sensor which concerns on this embodiment. It is an enlarged view of the optical sensor which concerns on this embodiment. It is an enlarged view of the chip | tip which mounts an optical sensor and an amplifier, (a) is a side view, (b) is a top view. An example of the change of the output voltage from the amplifier with respect to the center space | interval of a light emitting element and a light receiving element is shown. The measurement result of the primary moment integral value of the scattered light intensity with respect to the distance from the substrate surface to the subject is shown. It is a measurement result of blood flow volume, (a) shows the case where a commercially available blood flow meter is used, (b) shows the case where the blood flow meter concerning a present Example is used. It is a schematic block diagram of the conventional optical sensor. It is a bird's-eye view of the conventional optical sensor.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

  FIG. 1 is a schematic configuration diagram of a biological information measuring apparatus equipped with an optical sensor according to the present embodiment. A blood flow meter equipped with the optical sensor according to the present embodiment includes the optical sensor 1 according to the present embodiment, an amplifier 2, a drive arithmetic device 3, and an output unit 4. The drive arithmetic unit 3 can be configured as an LSI as a whole, can be configured integrally with the optical sensor 1 and the amplifier 2, and can be configured in a shape that can be easily mounted on a human body or the like.

  The optical sensor 1 emits light that irradiates the measurement target, receives interference light of inelastic scattered light and elastic scattered light from the measurement target, and outputs an electric signal obtained by photoelectrically converting the interference light to the amplifier 2. The amplifier 2 amplifies the electrical signal from the optical sensor 1 and outputs the amplified signal to the drive arithmetic device 3. The drive arithmetic device 3 causes the optical sensor 1 to emit light and performs arithmetic processing of the electric signal from the amplifier 2. By this calculation process, interference light from the measurement object and the subject is analyzed to obtain a measurement result. When the measurement target is red blood cells, this measurement result is biological information such as blood flow volume, blood volume, blood flow velocity, and pulse. The output unit 4 outputs the measurement result of the drive arithmetic device 3. Here, the output is, for example, a display on a small liquid crystal display.

  The drive arithmetic device 3 includes an AD converter 5, a drive circuit 6, a digital signal processor (DSP) 7, a power supply unit 8, and an interface 9. The drive circuit 6 drives the light emitting element provided in the optical sensor 1. The AD converter 5 converts the analog electric signal from the amplifier 2 into a digital signal. The DSP 7 performs arithmetic processing using the digital signal from the AD converter 5. The power supply unit 8 supplies power to the optical sensor 1, the amplifier 2, the drive arithmetic device 3, and the like. The interface 9 outputs the measurement result from the drive arithmetic device 3 to the output unit 4.

  In addition, although the biological information measuring device is mentioned as an example of the optical sensor which concerns on this embodiment, the optical sensor which concerns on this invention is applicable not only to a biological information measuring device but to a blood pressure monitor and other optical sensors. For example, if fruit is used instead of the subject, it functions as a fruit sugar content meter. This is because sucrose and fructose, which are sweet components of fruits, have absorption at a wavelength similar to that of glucose, which is a blood sugar component.

  The optical sensor 1 according to the present embodiment will be described with reference to FIGS. FIG. 2 is an enlarged view of the optical sensor according to the present embodiment. FIG. 3 is an enlarged view of a chip on which an optical sensor and an amplifier are mounted, in which (a) is a side view and (b) is a top view. The optical sensor includes a substrate 11, a light emitting element 16, a light receiving element 17, electric wiring patterns 12, 13, and 14, and a light shielding wall 18.

  Electrical wiring patterns 12, 13, and 14 are formed on the surface of the substrate 11 made of an insulating material. The electrical wiring pattern 12 is connected to the anode of the light receiving element 17 and to the amplifier 2 for detecting a minute signal (not shown). The electrical wiring pattern 13 is connected to the anode for the light emitting element 16 and is also connected to a drive circuit (reference numeral 6 shown in FIG. 1). The electric wiring pattern 14 is connected to the cathode shared by the light emitting element 16 and the light receiving element 17 and is also connected to each of the drive circuit (reference numeral 6 shown in FIG. 1) and the amplifier 2 (not shown).

  The light emitting element 16 and the light receiving element 17 are disposed on the same substrate 11 surface on which the electrical wiring patterns 12, 13, and 14 are formed. For example, it is disposed on the electric wiring pattern 14 via a silver paste film (not shown). Here, the light emitting element 16 is preferably a laser diode. Furthermore, in order to emit light in a direction perpendicular to the surface of the substrate 11, the light emitting element 16 is preferably a surface emitting type. The light receiving element 17 is preferably capable of receiving weak light, and is preferably a photodiode, for example.

  Electrodes are also provided on the upper surface of the light receiving element 17 and connected to the electric wiring pattern 12 by wire bonding. There is also an electrode on the upper surface of the light emitting element 16, and it is connected to the electric wiring pattern 13 by wire bonding. A current is injected into the electrical wiring pattern 13 from a drive circuit (reference numeral 6 shown in FIG. 1).

  Here, when the subject 100 is an erythrocyte in a capillary vessel, the component whose intensity is modulated by the Doppler shift is very weak, on the order of several hundred pW, and therefore the signal-to-noise ratio of the signal is deteriorated unless the light shielding wall 18 is provided. In the absence of the light shielding wall 18, the intensity of the weakly Doppler shifted inelastically scattered light component is buried in noise, and the blood flow velocity cannot be measured. Therefore, in the present embodiment, the light shielding wall 18 is provided on the substrate 11.

  The light shielding wall 18 is provided on the surface of the substrate 11 so as to surround the light receiving element 17, and has an incident window for allowing inelastic scattered light to enter the light receiving surface 17 a of the light receiving element 17. The entrance window is an opening provided on the subject 100 side. When the light shielding wall 18 has a cylindrical shape such as a cylindrical shape, one of the openings is fixed to the surface of the substrate 11 and the other of the openings serves as an incident window. Thereby, it is possible to prevent the direct light from the light emitting element 16 and the external light from the outside of the light shielding wall 18 from entering the light receiving element 17. The light shielding wall 18 has a cap shape that covers the light receiving element 17 in three dimensions, and the area of the incident window is preferably smaller than the area of the substrate 11. Thereby, the scattered light from a measuring object can be received efficiently.

  The light shielding wall 18 is preferably made of a non-conductive material. In the present embodiment, since the light emitting element 16, the light shielding wall 18, and the light receiving element 17 are disposed adjacent to each other, noise to the light emitting element 16 and the light receiving element 17 is likely to be generated by the current flowing through the light shielding wall 18. For example, when the entrance window is in close contact with the subject 100, the charge charged in the subject 100 may flow into the light emitting element 16 or the light receiving element 17. Therefore, noise to the light emitting element 16 and the light receiving element 17 can be prevented because the light shielding wall 18 is made of a non-conductive material.

  The light emitting element 16, the light shielding wall 18, and the light receiving element 17 are disposed adjacent to each other in order. For example, as illustrated in FIG. 3A, the light receiving element 17, the light shielding wall 18, and the light emitting element 16 are arranged with a slight gap therebetween. This gap is a gap when the distance a between the light receiving surface 17a of the light receiving element 17 and the light emitting surface 16a of the light emitting element 16 is minimized. In this way, by arranging the distance a between the light receiving surface 17a of the light receiving element 17 and the light emitting surface 16a of the light emitting element 16 to be minimum, the scattered light in which the light from the light emitting element 16 is scattered by the subject 100 is received. The element 17 can receive light efficiently.

  For example, consider a case where a 300 μm square light emitting element 16 and light receiving element 17 and a light shielding wall 18 having a thickness of 100 μm are used. In this case, the distance a between the light emitting element 16 and the light receiving element 17 on the surface of the substrate 11 is 400 μm at the minimum. At this time, if each necessary gap is 50 μm, the distance a between the light emitting element 16 and the light receiving element 17 on the surface of the substrate 11 is preferably about 500 μm. When the gap can be made smaller than 50 μm, the distance a between the light emitting element 16 and the light receiving element 17 on the surface of the substrate 11 is preferably 400 μm or more and 500 μm or less.

  In order to stably hold the light shielding wall 18 on the substrate 11, it is preferable that the light shielding wall 18 has a frame shape surrounding the light receiving element 17 on the substrate 11. The optical sensor is preferably small, and the typical size of the frame in this case has an inner diameter of 1 mm or more and 3 mm or less. When manufacturing a frame of this size, various shapes are conceivable. If the shape of the frame is rectangular, it is necessary to process the surrounding four sides, top and bottom cuts, and internal cutouts. However, if the shape is to be rotated, it can be easily manufactured with a lathe, greatly increasing the number of processes required for manufacturing. Can be reduced to a low price. Further, if the light shielding wall 18 has a shape other than the shape to be rotated, a rotating operation is necessary to determine the direction when mounting the number of manufacturing steps. However, if it is a shape to be rotated, a rotating operation is not necessary, and the cost is reduced by reducing the number of manufacturing steps.

  Therefore, it is preferable that the projected shape of the light shielding wall 18 on the surface of the substrate 11 is a shape to be rotated. The shape to be rotated is, for example, a polygon or a circle. In particular, the light shielding wall 18 is preferably cylindrical. Economy can be achieved by making the shape of the frame cylindrical.

  As will be described later in Example 2, the distance between the light emitting element 16 and the subject 100 is preferably 1.3 mm or more and 2.8 mm or less. In addition, the distance between the surface of the substrate 11 and the subject 100 is preferably approximately 2.0 mm. For this reason, the height of the light shielding wall 18 from the surface of the substrate 11 is preferably 1.5 mm or more and 3.0 mm or less, and more preferably approximately 2.0 mm. Thereby, if the entrance window of the light shielding wall 18 is brought into close contact with the subject 100, the distance between the light emitting element 16 and the subject 100 can be maintained at an appropriate constant distance. Accurate measurement.

  The method for manufacturing an optical sensor according to the present embodiment includes an arrangement step of sequentially arranging the light emitting element 16, the light shielding wall 18, and the light receiving element 17 on the surface of the substrate 11 of the optical sensor. For example, the light receiving element 17, the light shielding wall 18, and the light emitting element 16 are arranged in close contact with each other on the substrate 11 on which the electrical wiring patterns 12, 13, and 14 are formed. Here, when the light receiving element 17, the light shielding wall 18, and the light emitting element 16 are brought into close contact with each other, noise occurs in the light receiving element 17 or the operation of the light emitting element 16 becomes unstable. A gap is provided between the light-emitting elements 16 and the light-shielding walls 18 or between the light-emitting elements 16 and the light-shielding walls 18. Moreover, it is preferable to use the light shielding wall 18 made of a non-conductive material together with the gap instead of providing the gap. Thereby, the distance a between the light emitting element 16 and the light receiving element 17 on the surface of the substrate 11 can be minimized.

  Here, in the present embodiment, the common electric wiring pattern 14 is used for the cathodes of the light emitting element 16 and the light receiving element 17. Thereby, the wiring of the board | substrate 11 is simplified and it can contribute to size reduction and cost reduction of an optical sensor. Further, since the number of signal lines from the substrate 11 to the drive arithmetic unit 3 shown in FIG. 1 is reduced and the number of parts is reduced, the weight and cost are reduced. Furthermore, since a large tolerance can be obtained when die-bonding the light-emitting element 16 and the light-receiving element 17, an improvement in manufacturing yield can be expected, so that the cost can be reduced.

  Next, the operation of the optical sensor according to the present embodiment will be described with reference to FIG. When current is injected into the light emitting element 16 from the electric wiring pattern 13, the light emitting element 16 oscillates and emits light. The light emitted from the light emitting element 16 is irradiated to the subject 100 located outside the optical sensor. When the light emitting element 16 is brought close to the subject 100, light scattering occurs on the measurement object located inside the subject 100 and the surface of the subject 100, and scattered light including inelastic scattered light and elastic scattered light is blocked by the light shielding wall 18. And enters the light receiving element 17. The light receiving element 17 receives interference light in which inelastic scattered light and elastic scattered light interfere with light from the light emitting element scattered by the subject 100.

  This interference light includes interference components of elastic scattered light from a stationary subject 100 and inelastic scattered light from a measurement target in the subject 100. Here, the measurement target in the subject 100 is, for example, red blood cells moving in the capillary blood vessels. In this case, the living body which is the subject 100 is stationary, and the inelastic scattered light is Doppler shifted due to the movement of red blood cells, so that the interference components of the elastic scattered light and the inelastic scattered light interfere with each other. The interference component is frequency-analyzed to obtain the first moment integral of the power spectrum. Thereby, the optimal conditions for measuring the blood flow rate can be found.

Further, the inelastic scattered light from the inside of the subject is weak, and the fluctuation component of the scattered light intensity is about 1%. If the intensity of scattered light received by the light receiving element 17 is small, the amplification factor of the amplifier 2 needs to be very high, such as about 10 ⁸ V / A. However, when the amplification factor of the amplifier 2 is increased, there arises a problem that the amplification band is narrowed. Therefore, it is necessary to increase the optical signal intensity of the scattered light incident on the light receiving element 17. Thus, it is important to find a position where the signal intensity from the light receiving element 17 is maximum and the first moment integration is high.

  In this example, the optimum value of the center distance a between the light emitting element 16 and the light receiving element 17 shown in FIG. In the experiment, a 300 μm square laser diode and a photodiode were used for the light emitting element 16 and the light receiving element 17, and a light shielding wall 18 having a thickness of 100 μm was used. The output voltage from the amplifier 2 was measured while changing the center distance a between the light emitting element 16 and the light receiving element 17.

  When all of the light emitting element 16, the light shielding wall 18, and the light receiving element 17 were in contact, the center distance a between the light emitting element 16 and the light receiving element 17 was 300 μm. Considering the minimum space required for mounting the light emitting element 16 and the light receiving element 17 (50 μm on both sides of the light shielding wall), the minimum center distance a between the light emitting element 16 and the light receiving element 17 is 500 μm. Therefore, the minimum center distance a between the light emitting element 16 and the light receiving element 17 in this case is 500 μm.

  FIG. 4 shows an example of a change in the output voltage from the amplifier with respect to the center distance between the light emitting element and the light receiving element. In FIG. 4, the horizontal axis indicates the center distance between the light emitting element 16 and the light receiving element 17 shown in FIG. 3, and the vertical axis indicates the output voltage from the amplifier 2 shown in FIG. This data is normalized under the condition that the output light is 0.5 mW. As is apparent from FIG. 4, the output voltage from the amplifier 2 is higher as the center distance between the light emitting element 16 and the light receiving element 17 is smaller. For this reason, as the center distance between the light emitting element 16 and the light receiving element 17 is narrower, the signal intensity of the scattered light to the light receiving element is higher, and optimal measurement can be performed at 500 μm where the center distance between the light emitting element 16 and the light receiving element 17 is minimized. found.

  In this example, the optimum value of the distance b between the light emitting element 16 and the subject 100 shown in FIG. In the experiment, a laser diode and a photodiode having a thickness of 0.2 mm were used for the light emitting element 16 and the light receiving element 17. Then, while changing the distance c between the substrate 11 and the subject 100, the first moment integral value of the power spectrum of the time variation of the intensity of the scattered light detected by the light receiving element 17 was calculated. Here, the first moment integral is an index because it is proportional to the blood flow as described above.

  FIG. 5 shows the measurement result of the first moment integrated value of the scattered light intensity with respect to the distance from the substrate surface to the subject. In FIG. 5, the horizontal axis represents the distance c from the substrate surface to the subject, and the vertical axis represents the first moment integral value. Here, the primary moment integral value is normalized by the square of the average intensity of the scattered light received by the light receiving element 17. As shown in the graph, the primary moment integral value is maximum when the distance c is around 2 mm. At this time, since the thicknesses of the light emitting element and the light receiving element are both 0.2 mm, the blood flow rate is reduced when the distance between the light emitting element and the light receiving element and the subject 100 (symbol b in FIG. 3) is about 1.8 mm. It has been found that optimal measurement can be performed.

  In addition, since the peak begins to appear clearly when the first moment integral value is 0.08 or more, it is considered that the effect appears when the distance c is in the range of 1.3 mm to 3.8 mm. For this reason, the distance c is 1.3 mm or more and 3.8 mm or less, that is, the distance between the light emitting element and the light receiving element and the subject (symbol b in FIG. 3) is 1.1 mm or more and 3.6 mm or less. It is preferable.

  Further, when the distance c is 1.5 mm and 3.0 mm, the primary moment integral values are substantially the same, so it can be said that the primary moment integral values are equivalent. For this reason, the distance c is 1.5 mm or more and 3.0 mm or less, that is, the distance between the light emitting element and the light receiving element and the subject (symbol b in FIG. 3) is 1.3 mm or more and 2.8 mm or less. Is preferred.

  When the distance c from the surface of the substrate 11 is 1.8 mm, the primary moment integral value is maximum. Therefore, the distance b between the light emitting element 16 and the light receiving element 17 and the subject 100 is preferably 1.6.

  In this example, it was confirmed by experiments whether the optical sensor shown in FIG. 3 can actually observe fluctuations in blood flow. In the experiment, a commercially available blood flow meter and an optical sensor of the blood flow meter according to this example were adhered to the index finger with a double-sided tape, the wrist was squeezed to block blood, and then the blood flow change when gradually released was observed. .

  6A and 6B show measurement results of blood flow. FIG. 6A shows a case where a commercially available blood flow meter is used, and FIG. 6B shows a case where the blood flow meter according to the present embodiment is used. The trend of change is almost the same. Therefore, it was confirmed that the optical sensor shown in FIG. 3 can actually observe fluctuations in blood flow.

  The optical sensor and the manufacturing method thereof of the present invention can be applied to the medical equipment industry and the health / beauty industry for manufacturing a biological information measuring device such as a blood pressure monitor.

1: Optical sensor 2: Amplifier 3: Drive arithmetic device 4: Output unit 5: AD converter 6: Drive circuit 7: DSP
8: Power supply unit 9: Interface 11: Boards 12, 13, 14: Electrical wiring pattern 16: Light emitting element 16a: Light emitting surface center 17: Light receiving element 17a: Light receiving surface center 18: Light shielding wall 100: Subject 101: Optical sensor 102, 103, 104, 105: Electric wiring pattern 108: Light shielding wall

Claims (10)

A light emitting element that emits light;
A light receiving element that receives interference light of inelastically scattered light scattered from a measurement object in which light from the light emitting element moves inside the subject and elastic scattered light scattered from a stationary object inside the subject; An optical sensor disposed on the same substrate surface on which an electrical wiring pattern is formed,
A light-shielding wall provided on the substrate surface so as to surround the light-receiving element, and having an incident window for allowing the interference light to enter the light-receiving surface of the light-receiving element;
The optical sensor, wherein the light emitting element, the light shielding wall, and the light receiving element are arranged adjacent to each other in order.   The optical sensor according to claim 1, wherein a distance between the light emitting element and the subject is 1.3 mm or more and 2.8 mm or less.   The optical sensor according to claim 1, wherein a distance between the light emitting element and the light receiving element on the substrate surface is 500 μm or less.   The optical sensor according to claim 1, wherein a projection shape of the light shielding wall onto the substrate surface is a shape to be rotated.   The optical sensor according to claim 1, wherein the light shielding wall is made of a nonconductive material.   The optical sensor according to claim 1, wherein a distance between the light emitting element and the light receiving element on the substrate surface is approximately 500 μm.   The optical sensor according to claim 1, 3, 4, 5, or 6, wherein a distance between the substrate surface and the subject is approximately 2.0 mm.   2. The light shielding wall is cylindrical, wherein one of the cylindrical openings is fixed to the substrate surface, and the other of the cylindrical openings is the incident window. 8. The optical sensor according to any one of 7 to 7.   8. The optical device according to claim 1, wherein the light shielding wall has a cap shape that covers the light receiving element in three dimensions, and an area of the incident window is smaller than an area on the substrate surface. Sensor. A method for producing an optical sensor according to any one of claims 1 to 9,
The manufacturing method of the optical sensor characterized by having the arrangement | positioning process which arrange | positions the said light emitting element, the said light-shielding wall, and the said light receiving element adjacently in order.

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