JP4718324B2 - Optical sensor and sensor unit thereof - Google Patents

Description

  The present invention relates to an optical sensor for measuring blood flow volume, blood volume, blood flow velocity, pulse, etc. in a target biological tissue using scattered light from the biological tissue.

  As documents are listed for conventional blood flow meter, there is Patent Document 1. 16 and 17 are diagrams showing the configuration of the sensor chip of the conventional blood flow meter shown in the same document. FIG. 16 (a) is a top view, FIG. 16 (b) is an AA ′ sectional view, and FIG. a) is a BB ′ sectional view, and FIG. 17B is a CC ′ sectional view. As shown in FIGS. 16A and 16B, in the conventional sensor chip, an electrode 122 is formed on a semiconductor substrate (silicon substrate 121: silicon bench using a (100) silicon substrate) made of surface-thermally oxidized silicon. Then, a semiconductor laser (LD) 123, which is a light emitting element, is formed on the electrode 122 in the recess surrounded by the inclined surface via a solder film (not shown). Similarly, an electrode 124 is formed on the same silicon substrate 121, and a photodiode (surface incident PD 125) as a light receiving element is formed on the electrode 124 in a recess surrounded by an inclined surface via a solder film. Further, a cover substrate 126 is provided on the silicon substrate 121. Here, synthetic quartz is used for the cover substrate 126. The cover substrate 126 is manufactured by dicing a 6-inch synthetic quartz wafer. For example, a surface emitting laser is used as the semiconductor laser. The semiconductor laser 123 and the photodiode 125 are bonded to the silicon substrate 121 via a solder film. By forming the light emitting element and light receiving element on the same semiconductor substrate, each optical element need only be two-dimensionally positioned and does not require three-dimensional alignment, thus reducing the adjustment process and enabling mass production. Thus, cost reduction can be realized.

  As shown in FIGS. 16A and 16B, a metal (TiPtAu) film is patterned as a light shielding film 127 on the silicon substrate on the side where the photodiode 125 is mounted by a conventional technique. As a result, stray light entering the photodiode 125 from the semiconductor laser 123 through the silicon substrate 121 can be prevented. If the light shielding film is not provided, light may reach the photodiode 125 from the semiconductor laser without passing through the living tissue. Then, the scattered light component whose intensity is modulated by scattered light (Doppler-shifted light) from the red blood cells in the capillary blood vessels received by the sensor chip is very weak, about several hundred pW. The S / N ratio becomes worse. Therefore, in the absence of the light shielding film 127, the intensity of the weak Doppler shifted scattered light component is buried, and the blood flow velocity cannot be detected.

  As shown in FIGS. 16A and 17A, this sensor chip uses a surface emitting semiconductor laser 161 as a light emitting element. Here, it is prepared by wet anisotropic etching (100) silicon substrate. Further, the surface emitting LD161 is connected to the electrode 122 by a wire 129.

  Further, as shown in FIG. 17A, since the refractive lens 162 is formed on the cover substrate 126, the light from the LD 161 is irradiated to an external living tissue in the state of diverging light, convergent light, and parallel light. Is possible. The lens formed on the cover substrate 126 is not limited to the refractive lens 130 but may be a binary lens or a Fresnel lens that can be formed using a semiconductor process.

  Further, as shown in FIG. 17B, this sensor chip uses a surface incident PDl25. In addition, a light shielding film 131 that blocks unnecessary scattered light is formed by patterning on the upper and lower surfaces of the cover substrate 126 by photolithography, and the scattered light from the biological tissue is incident on the surface incident PD 125 from the opening in the light shielding film. This light-shielding film 131 can efficiently detect scattered light (Doppler-shifted light) from red blood cells in the moving capillary in the living tissue. The plane incident PD is connected to the electrode by a wire. Further, as is clear from this document, a light emitting element and a light receiving element can be directly mounted on a semiconductor substrate by a combination using a surface emitting LD as a light emitting element and a surface incident PD as a light receiving element.

  In such a blood flow meter, scattered light from a stationary biological tissue and scattered light from red blood cells (scattering particles) moving in the capillary of the biological tissue (subject to Doppler shift Δf depending on the blood flow). By detecting interference light (scattered light) (heterodyne detection), blood flow volume, blood volume, blood flow velocity, and pulse are measured. The measurement principle is known, for example, described in Non-Patent Document 1.

  Next, another example of the sensor chip of the conventional blood flow meter shown in the same document will be described with reference to FIGS. 18A is a top view, FIG. 18B is an A-A ′ sectional view, FIG. 19A is a B-B ′ sectional view, and FIG. 19B is a C-C ′ sectional view.

  As shown in FIGS. 18 (a) and 18 (b), this sensor chip is a silicon bench using a silicon substrate (silicon substrate 221: 9.7 ° off-axis cut (10) silicon substrate) made of surface-oxidized silicon. ), And a semiconductor laser (edge emitting LD 223) as a light emitting element is formed on the electrode 222 in a recess surrounded by an inclined surface via a solder film (not shown). Similarly, an electrode 224 is formed on the same silicon substrate 221, and a photodiode (surface incident PD 225) that is a light receiving element is formed on the electrode 224 in a recess surrounded by an inclined surface via a solder film.

  Further, a cover substrate 226 is provided on the silicon substrate 221. Here, synthetic quartz is used for the cover substrate 226. The cover substrate 226 is manufactured by dicing a 6-inch synthetic quartz wafer.

  For example, a DFB laser having a wavelength of 1.3 μm is used as the semiconductor laser (edge emitting LD 223). By using a DFB laser with a wavelength of 1.3 μm, it is possible to detect a waveform that transmits light deep into the subcutaneous tissue.

  The semiconductor laser 223 and the photodiode 225 are bonded to the silicon substrate 221 via a solder film. As a technique for bonding a light emitting element and a light receiving element on a semiconductor substrate with high accuracy, there is a technique disclosed in Japanese Patent Laid-Open No. 9-55393 (element bonding method and apparatus).

  By forming the light emitting element and light receiving element on the same semiconductor substrate, each optical element need only be two-dimensionally positioned and does not require three-dimensional alignment, thus reducing the adjustment process and enabling mass production. Thus, cost reduction can be realized.

  As shown in FIGS. 18A and 18B, in this document, a metal (TiPtAu) film is patterned as a light shielding film 227 on the silicon substrate on the side where the photodiode 225 is mounted. As a result, stray light that enters the photodiode 225 from the semiconductor laser 223 through the silicon substrate 221 can be prevented.

  That is, since light with a wavelength (1.3 μm) is transmitted through silicon, when a semiconductor laser with a wavelength of 1.3 μm (DFB laser) is used as a light emitting element, light is transmitted from the semiconductor laser to the photodiode 225 without passing through living tissue. May arrive.

  On the other hand, the scattered light component whose intensity is modulated by the scattered light (Doppler-shifted light) from the red blood cells in the capillaries received by the sensor chip is very weak, about several hundred pW. The S / N ratio becomes worse. Without this light shielding film 227, the intensity of the weak Doppler shifted scattered light component is buried, and the blood flow velocity cannot be detected.

  As shown in FIGS. 18 (a) and 19 (a), in this document, an edge-emitting semiconductor laser 223 (DFB laser having a wavelength of 1.3 μm) is used as a light emitting element, and the emitted light is reflected upward. An inclined surface to be formed is formed on the silicon semiconductor substrate. Here, a (100) silicon substrate cut off by 9.7 ° is fabricated by wet anisotropic etching.

  In this case, since the (111) plane appears at 45 °, the metal film 28 (TiPtAu) is vapor-deposited on the inclined surface and used as a mirror. When such an off-axis cut substrate is not used, it is also possible to use the (111) plane appearing at 54.7 ° as a mirror.

  Furthermore, edge emitting LD223 is connected to the electrode 222 by a wire 229. Further, as shown in FIG. 19A, since the binary lens 230 is formed on the cover substrate 226 by a semiconductor process, the light from the LD 223 is diverged light, convergent light, and parallel light to an external living tissue. Irradiation is possible.

  The lens formed on the cover substrate 226 is not limited to the binary lens 230 but may be a refractive lens, a Fresnel lens, or the like.

  As shown in FIG. 19B, the same document uses a surface incident PD 225. Further, in the form of this document, the light shielding film 231 that blocks unnecessary scattered light is formed by patterning on the upper and lower surfaces of the cover substrate 226 by photolithography, and the scattered light from the ecological tissue is incident on the surface from the opening in the light shielding film. Incident on PD225. The light-shielding film 231 can efficiently detect scattered light (Doppler-shifted light) from red blood cells in the moving capillary in the living tissue.

  The surface incident PD225 is connected to the electrode 224 by a wire 232. Since the sensor chip is configured to use the silicon substrate 221 having the shape as described above and the cover substrate 226, the functions of the light shielding plate and the protective cover glass in the sensor chip can be formed by a small number of processes, and the manufacturing cost is reduced. .

  The operation of the sensor chip will be described next.

  The semiconductor laser 223 is injected current from the electrode 222 oscillates the semiconductor laser 223. In order to oscillate the power as constant as possible, an auto power control photodiode (not shown) is arranged on the rear end face of the semiconductor laser 223 and the output of the semiconductor laser 223 is monitored so that the power is always constant. In addition, the injection current of the semiconductor laser 223 is controlled by a feedback circuit. Light emitted from the semiconductor laser 223 is irradiated to an external living tissue through a cover substrate 226 disposed on the silicon substrate 221. When this sensor chip is brought close to a living tissue such as skin, light scattering occurs, and the scattered light again enters the photodiode through the cover substrate 226.

This scattered light includes interference components of scattered light from a stationary biological tissue and scattered light (Doppler-shifted light) from moving red blood cells in capillaries of the biological tissue. Therefore, the blood flow velocity can be obtained by frequency analysis of this signal. The experiment confirmed that a linear relationship was established between the fluid velocity and the Doppler shift frequency using a solution in which fine particles were dispersed in a fluid. Further, the intensity of the scattered light corresponds to the amount of blood that is moving, and the blood flow volume is obtained by the product of the blood flow velocity and the blood volume.
JP 2004-229920 A JP 2002-330936 A MDStern: “In vivo evaluation of microcirculation by coherent light scattering” Nature, col. 254, pp. 56-58 (1975)

  However, in order to actually use such a conventional blood flow meter, a cover substrate in which a light shielding film for selecting unnecessary scattered light is formed on the top and bottom in the surface incident PD portion is required. Since the light shielding film pattern on the upper side of the cover substrate is constantly in contact with a living tissue such as a finger during blood flow measurement, the light shielding film pattern is easily peeled off, and the light shielding is deteriorated and the measurement accuracy is lowered.

  Further, since a special semiconductor substrate such as a 9.7 degree off-axis silicon substrate is used, an expensive material is used. Further, in the manufacturing process, it is necessary to perform etching processing on the semiconductor substrate, which increases the manufacturing cost.

  Furthermore, it is necessary for the electrical wiring pattern to reach the concave portion on the silicon substrate, and it is necessary to form the electrical wiring pattern on the inclined surface, which is difficult to manufacture, has a low success rate, and often breaks. there were.

  Furthermore, since the light emitting unit and the light receiving unit have a common cover substrate, light directly emitted from the laser, which is the light emitting element, reflects inside the cover substrate and passes through the hole pattern of the shielding film. There is a drawback in that it directly reaches a certain surface incident PD and interferes with scattered light from a biological sample to cause noise.

  SUMMARY An advantage of some aspects of the invention is that it provides an optical sensor and a sensor unit that are easy to manufacture, realize low cost and high accuracy.

The above-described problem is a sensor in an optical sensor that emits light emitted from a light emitting element toward an external living tissue and receives scattered light from the living tissue by a light receiving element to measure a value related to blood flow in the living tissue. Each of the light emitting element and the light receiving element is disposed on a wiring pattern formed on the surface of the same plane substrate, the light emitting element and the light receiving element are electrically connected to the wiring pattern, and the light receiving element The sensor unit has a light shielding structure made of an opaque material capable of blocking unnecessary scattered light on the element, and the light shielding structure has a cap shape with a hole in the upper surface. it can.

  The present invention further includes an integrated circuit including the sensor unit, a circuit that drives the light emitting element, and a digital signal processor that processes a signal received from the sensor unit and calculates a value related to blood flow. It can also be configured as a featured optical sensor.

As described above, according to the present invention, the light emitting element and the light receiving element are installed on an inexpensive flat substrate that is simply provided with an electrical wiring pattern, and the light shielding frame or the light shielding cap is disposed to thereby install the sensor unit. With this configuration, it is possible to realize an optical sensor with high measurement accuracy that can remove unnecessary scattered light, does not deteriorate the light-shielding film pattern, does not require mounting effort, and reduces manufacturing costs.

  Embodiments of the present invention will be described below with reference to the drawings.

[First embodiment]
FIG. 1 is a diagram showing a configuration of a blood flow meter as a first embodiment of the optical sensor of the present invention. As shown in the figure, the blood flow meter of this embodiment includes a sensor chip 1 that receives scattered light reflected by irradiating light on a living tissue, an amplifier 2 that amplifies the received light, and a light emitting element (LD). It has a drive / arithmetic unit 3 for obtaining blood flow by driving and analyzing scattered light, and an output unit 4 for displaying the obtained blood flow and the like.
The sensor chip 1 is integrated on a semiconductor substrate. The drive / arithmetic apparatus 3 includes an A / D converter 5, an LD driver 6, a digital signal processor (DSP) 7 that performs an operation for obtaining a blood flow from the received signal, a power supply unit 8, and an interface 9. The output unit 4 is connected to a small liquid crystal display or the like. The drive / arithmetic apparatus 3 can be configured as an LSI as a whole, can be configured integrally with the sensor chip and the amplifier, and can be configured in a shape that can be easily mounted on a human body or the like.

  In this embodiment, a blood flow meter is used as an example of the optical sensor. However, the sensor unit of the present invention can be applied not only to a blood flow meter but also to a blood pressure monitor and other optical sensors.

  Next, the sensor chip 1 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a top view of the sensor chip of the first embodiment. FIG. 3 is a bird's eye view. Electrical wiring patterns 12, 13, 14, 15 are formed on a silicon substrate 11 with an oxide film, which is an insulating material. The electrical wiring pattern 12 is an anode for a photodiode, and the electrical wiring pattern 13 is a cathode for a photodiode. It is connected to an amplifier (not shown) for detecting minute signals. The electrical wiring pattern 15 is an anode for a semiconductor laser, and the electrical wiring pattern 14 is a cathode for a semiconductor laser, and is connected to a semiconductor laser driving circuit (LD driver).

  A semiconductor laser 16 (surface emitting LD), which is a light emitting element, is formed on the electrical wiring pattern 14 via a solder film (not shown). Similarly, a photodiode 17 (surface incident PD) as a light receiving element is formed on the electric wiring pattern 13 via a solder film (not shown).

  There is also an electrode on the upper surface of the photodiode 17 and connected to the electric wiring pattern 12 by wire bonding. This is connected to the anode (positive electrode).

  Furthermore, an electrode is also provided on the upper surface of the semiconductor laser 16 and is connected to the electric wiring pattern 15 by wire bonding. Here, current is supplied from an anode (plus electrode) from a laser driving circuit (LD driver) (not shown). Injected. Further, a light shielding frame 18 is provided on the substrate so as to surround the photodiode 17 (surface incident PD) in order to avoid light coming directly from the light emitting element to the light receiving element.

  That is, the scattered light component intensity-modulated by scattered light (Doppler-shifted light) from the red blood cells in the capillaries received by the sensor chip is very weak, about several hundred pW. The S / N ratio becomes worse. In the absence of the light-shielding frame 18, the intensity of the weak Doppler-shifted scattered light component is buried and the blood flow velocity cannot be detected.

  The sensor chip is configured to use the silicon substrate with an oxide film as described above, a pattern on the silicon substrate, and a light shielding frame, so that the functions of the silicon substrate having a complicated shape and the light shielding cover substrate in the conventional sensor chip can be achieved. can be formed by inexpensive materials and fewer steps, manufacturing cost is inexpensive.

  The operation of the sensor chip will be described next. When a current is injected from the electrode 15 into the semiconductor laser 16, the semiconductor laser 16 oscillates. The light emitted from the semiconductor laser 16 is irradiated to an external living tissue. When this sensor chip is brought close to a living tissue such as skin, light scattering occurs, and the scattered light enters the photodiode 17 through the shielding frame 18. This scattered light includes interference components of scattered light from a stationary biological tissue and scattered light (Doppler-shifted light) from moving red blood cells in capillaries of the biological tissue. Therefore, the blood flow velocity can be obtained by frequency analysis of this signal. The experiment confirmed that a linear relationship was established between the fluid velocity and the Doppler shift frequency using a solution in which fine particles were dispersed in a fluid.

  Further, the intensity of the scattered light corresponds to the amount of blood that is moving, and the blood flow volume is obtained by the product of the blood flow velocity and the blood volume.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a top view of a portion of the sensor chip of the second embodiment on the photodiode side, and FIG. 5 is a bird's eye view thereof.

In the present embodiment, the portion on the semiconductor laser side can have the same configuration as in the first embodiment. The basic configuration of this embodiment is the same as that of the first embodiment, but a light-shielding cap 28 is used instead of the light-shielding frame in order to shield light directly incident on the light-receiving element from the light-emitting element. . The light shielding cap has a hole 29 in the upper surface of the rectangular parallelepiped cap, and has a disadvantage that the amount of light that can be received is smaller than that of the light shielding frame. Has the advantage of improving. The basic operation is the same as in the first embodiment.
[Third embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a top view of a portion of the sensor chip of the third embodiment on the semiconductor laser side, and FIG. 7 is a bird's eye view thereof.

  In the present embodiment, the portion on the photodiode side can have the same configuration as in the first or second embodiment. In this embodiment, the basic configuration is the same as that of the first and second embodiments, except that an edge emitting semiconductor laser 36 is used for the light emitting element.

  Further, a 90-degree bending mirror 30 is installed for changing the traveling direction of the laser beam emitted from the end face vertically upward. The 90-degree bending mirror 30 is formed by forming a mirror surface on the oblique side of a prism column having a right isosceles triangle by metal vapor deposition or the like. Compared to the case of using a surface-emitting type semiconductor laser, the 90-degree bending mirror 30 is required, which increases the number of parts and causes a cost increase. However, the edge emitting semiconductor laser 36 can be selected. Therefore, there is an advantage that a high-quality laser for optical communication can be used, and a long-life and stable distributed feedback laser having a wavelength of 1.3 μm can be used. The basic operation is the same as in the first embodiment.

  As the 90-degree bending mirror 30, a trapezoidal prism may be used as shown in FIG. Further, a pentagonal prism may be used as shown in FIG. The trapezoidal prism has an advantage that it is easy to handle with vacuum tweezers or the like at the time of mounting by providing a flat portion on the top. In addition to the advantages of trapezoidal prisms, pentagonal prisms have the advantage that they are less prone to chipping because there are no sharp corners.

In addition, although the material of a prism can consider glass, a fused silica, etc., if it produces with a plastic, there exists an advantage that mass production becomes possible by the method of injection molding.
[Fourth embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a top view of the sensor chip of the fourth embodiment, and FIG. 10 is a bird's-eye view of the sensor chip of the fourth embodiment.

  In this sensor chip, electrical wiring patterns 42, 43, and 45 are formed on a silicon substrate 41 with an oxide film, which is an insulating material. The electrical wiring pattern 42 is an anode for a photodiode, and an amplifier for detecting a minute signal. (Not shown). The electric wiring pattern 43 is a common cathode for the photodiode and the semiconductor laser, and is connected to the ground. The electrical wiring pattern 45 is an anode for a semiconductor laser and is connected to a semiconductor laser driving circuit (LD driver). Also, the semiconductor laser drive circuit (LD driver) and the electrical wiring pattern 43 which is the cathode of the amplifier are naturally connected to the ground.

  A semiconductor laser 46 (surface emitting LD) which is a light emitting element is formed on a T-shaped electric wiring pattern 43 via a solder film (not shown). Similarly, a photodiode 47 (surface incident PD) as a light receiving element is formed on the electric wiring pattern 43 via a solder film (not shown).

  Both the electrode on the bottom surface of the semiconductor laser 46 and the electrode on the bottom surface of the photodiode 47 are cathodes (minus electrodes), and are bonded to the electric wiring pattern 43 on the silicon substrate with oxide film via a solder film. There is also an electrode on the upper surface of the photodiode 47, which is connected to the electric wiring pattern 42 by wire bonding. This is connected to the anode (positive electrode). Further, an electrode is also provided on the upper surface of the semiconductor laser 46, and is connected to the electric wiring pattern 45 by wire bonding. Here, current is supplied from an anode (plus electrode) from a laser driving circuit (LD driver) (not shown). Injected.

Further, a light shielding frame 48 is provided on the silicon substrate with an oxide film so as to surround the photodiode 47 (surface incident PD) in order to avoid light coming directly from the light emitting element to the light receiving element. The basic operation is the same as in the first embodiment.
[Fifth embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a top view of the photodiode side portion of the sensor chip of the fifth embodiment, and FIG. 12 is a bird's eye view thereof.

In the present embodiment, the portion on the semiconductor laser side can be configured similarly to the fourth embodiment. In this embodiment, the basic configuration is the same as that of the fourth embodiment, but a light shielding cap 58 is used in place of the light shielding frame in order to shield light directly incident on the light receiving element from the light emitting element. ing. The light shielding cap 58 has a hole 59 formed in the upper surface of a rectangular parallelepiped cap, and has the disadvantage that the amount of light that can be received is smaller than that of the light shielding frame, but has the advantage that the signal S / N ratio is improved. The basic operation is the same as in the fourth embodiment.
[Sixth embodiment]
Next, a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a top view of the semiconductor laser side portion of the sensor chip of the sixth embodiment, and FIG. 14 is a bird's-eye view thereof.

  In the present embodiment, the portion on the photodiode side can be configured similarly to the fourth and fifth embodiments. In this embodiment, the basic configuration is the same as that of the fourth and fifth embodiments, except that an edge emitting semiconductor laser 66 is used for the light emitting element.

  A 90-degree bending mirror 60 is installed to change the traveling direction of the laser beam emitted from the end face vertically upward. The 90-degree bending mirror 60 is formed by forming a mirror surface on the oblique side of a prism column having a right isosceles triangle by metal vapor deposition or the like. Compared to the case of using a surface-emitting type semiconductor laser, the 90-degree bending mirror 60 is required, which increases the number of parts and causes a cost increase. However, the edge emitting semiconductor laser 66 can be selected. Therefore, there is an advantage that a high-quality laser for optical communication can be used, and a long-life and stable distributed feedback laser having a wavelength of 1.3 μm can be used. The basic operation is the same as in the fourth and fifth embodiments.

  Similarly to the third embodiment, as the 90-degree bending mirror 60, a trapezoidal prism shown in FIG. 8A may be used in addition to a prism column having a right isosceles triangle. Further, a pentagonal prism shown in FIG. 8B may be used. The trapezoidal prism has an advantage that it is easy to handle with vacuum tweezers or the like at the time of mounting by providing a flat portion on the top. In addition to the advantages of trapezoidal prisms, pentagonal prisms have the advantage that they are less prone to chipping because there are no sharp corners.

  In addition, although the material of a prism can consider glass, a fused silica, etc., if it produces with a plastic, there exists an advantage that mass production becomes possible by the method of injection molding.

  Next, effects of the embodiment of the present invention will be described. Figure 15 is a data in blood flow as measured by the apparatus of the first embodiment. The upper graph is the time transition of the blood flow measured by this apparatus, and the lower graph is the data simultaneously measured by a commercially available standard blood flow meter. This figure shows blood flow when the device is applied to a finger, blood is blocked by tightening the wrist strongly, gradually opened, and finally completely opened. This device and a commercially available standard device show a very good match, and it can be seen that there is no inferiority.

  Although FIG. 15 shows data according to the first embodiment, similar data can be obtained using the second to sixth embodiments.

  In addition, the substrate used in the first to sixth embodiments is a silicon substrate having a planar surface in which a thermal oxide film is attached and the surface is an insulator and an electrode pattern is applied. The same effect can be obtained by using an insulator and a material capable of forming an electrode pattern on the surface, such as a silicon substrate provided with a film or a glass epoxy substrate.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

It is a diagram showing a configuration of a blood flow meter according to an embodiment of the present invention. It is a top view of the sensor chip of a first embodiment in the present invention. It is a bird's-eye view of a sensor chip of the first embodiment of the present invention. It is a top view of the sensor chip of a second embodiment in the present invention. It is a bird's-eye view of the sensor chip of the second embodiment of the present invention. It is a top view of the sensor chip of 3rd embodiment in this invention. It is a bird's-eye view of the sensor chip of the third embodiment of the present invention. It is a figure which shows the other example of the 90 degree | times bending mirror in 3rd and 6th embodiment. It is a top view of a sensor chip according to a fourth embodiment of the present invention. It is a bird's-eye view of the sensor chip of the fourth embodiment of the present invention. It is a top view of the sensor chip of 5th embodiment in this invention. It is a bird's-eye view of the sensor chip of the fifth embodiment of the present invention. It is a top view of the sensor chip of 6th embodiment in this invention. It is a bird's-eye view of the sensor chip of the sixth embodiment of the present invention. It is a figure which shows the blood flow data measured using the sensor chip of 1st embodiment in this invention, (a) is the data measured with the apparatus of this embodiment, (b) is the data by the commercial item measured simultaneously. is there. It is a figure which shows the sensor chip of the conventional blood flow meter, (a) is a top view, (b) is AA 'sectional drawing. (A) is sectional drawing of the part containing the light emitting element in the sensor chip of the conventional blood flow meter, (b) is sectional drawing of the part containing the light receiving element in the sensor chip of the conventional blood flow meter. It is a figure which shows the sensor chip of the conventional blood flow meter, (a) is a top view, (b) is AA 'sectional drawing. (A) is sectional drawing of the part containing the light emitting element in the sensor chip of the conventional blood flow meter, (b) is sectional drawing of the part containing the light receiving element in the sensor chip of the conventional blood flow meter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor chip 2 Amplifier 3 Drive / arithmetic unit 4 Output part 5 A / D converter 6 LD driver 7 Digital signal processor (DSP)
8 Power supply unit 9 Interface 11 Substrate 12 to 15 Electric wiring pattern 17 Photodiode (surface incident PD)
18 Light-shielding frame 21 Substrate 22, 23 Electrical wiring pattern 28 Light-shielding cap 29 Hole 31 Substrate 34, 35 Electrical wiring pattern 36 Semiconductor laser (edge emitting LD)
30 90 degree bending mirror 41 Substrate 42-45 Electric wiring pattern 46 Semiconductor laser (surface emitting LD)
47 Photodiode (surface incident PD)
48 Light shielding frame 51 Substrate 52, 53 Electric wiring pattern 58 Light shielding cap 59 Hole 61 Substrate 63, 65 Electric wiring pattern 66 Semiconductor laser (end surface emitting LD)
60 90-degree bending mirror 121 Silicon substrate 122, 124 Electrode 125 Surface incidence PD
126 Cover substrate 127 Light shielding film 128 Metal film for mirror 129 Wire 161 Surface emitting LD
162 Refractive lens 221 Silicon substrate 222 Electrode 223 End-emitting LD
224 electrode 225 surface incident PD
226 Cover substrate 227 Shielding film 228 Mirror metal film 229 Wire 230 Binary lens 231 Shielding film 232 Wire

Claims (8)

A sensor unit in an optical sensor that emits light emitted from a light emitting element toward an external biological tissue, receives scattered light from the biological tissue with a light receiving element, and measures a value related to blood flow in the biological tissue,
Each of the light emitting element and the light receiving element is disposed on a wiring pattern formed on the surface of the same plane substrate, and each of the light emitting element and the light receiving element is electrically connected to the wiring pattern, and unnecessary scattered light is transmitted to the light receiving element. a sensor unit for arranging the fabricated light shielding structure of an opaque material which can be blocked and
The sensor part according to claim 1, wherein the light shielding structure has a cap shape with a hole in an upper surface .   The sensor unit according to claim 1, wherein the substrate is made of a non-conductive material.   The sensor unit according to claim 1, wherein the substrate is a semiconductor substrate having a non-conductive material formed on a surface thereof. Sensor unit according to any one of claims 1 to 3, characterized by using a surface emitting semiconductor laser as the light emitting element. Sensor unit according to any one of claims 1 to 4, characterized by using a surface illuminated photodiode as the light receiving element. Sensor unit according to any one of claims 1 to 3, wherein the use of edge-emitting semiconductor laser as the light emitting element. The sensor unit includes an optical bending mirror for changing a traveling direction of light emitted from the edge emitting semiconductor laser,
The sensor unit according to claim 6 , wherein the light folding mirror is formed using a triangular prism, a trapezoidal prism, or a pentagonal prism. A sensor unit according to any one of claims 1 to 7 , a circuit for driving the light emitting element, a digital signal processor for processing a signal received from the sensor unit and calculating a value relating to the blood flow; An optical circuit comprising: an integrated circuit comprising:

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