JPH0622323Y2 - Optical sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an optical sensor, and more particularly, to the transmission of light from one side of a subject to the other side, and the magnitude of the absorption of this transmitted light by the subject. The present invention relates to an optical sensor that detects a change in depth.

[Prior Art] Conventionally, light is transmitted from one side of the fingertip skin to the other side, and the transmittance (reflectance) of this light due to the blood flow of the finger or the like.
There is known a device for detecting a change in the pulse width, processing the detection signal, and then calculating the pulse and blood pressure values. An example of an optical sensor used in such a device is disclosed in Japanese Utility Model Laid-Open No. 60-158803.

3 is a perspective view of the above-disclosed optical sensor, FIG. 4 is a cross-sectional view of the optical sensor shown in FIG. 3, and FIG. 5 is the optical sensor shown in FIG. FIG. 6 is a cross-sectional view showing a mounted state, and FIG. 6 is a perspective view of a fixing tape for fixing the optical sensor to a finger.

First, a conventional optical sensor 8 will be described with reference to FIGS. 3 to 6. The optical sensor 8 shown in FIG. 3 transmits light from one side of the finger to the other side and detects a change in the size of the transmitted light due to the finger. For this purpose, the light emitting element 2 and the light receiving element 3 are arranged on the flexible film substrate 1 at a predetermined interval corresponding to the size of the finger. Then, a transparent and flexible light-transmitting film 6 is attached to the film substrate 2 so as to cover the light emitting element 2 and the light receiving element 3.

Next, a method of using the optical sensor 8 shown in FIG. 3 will be described with reference to FIGS. As shown in FIG. 4, an optical sensor 8 is wound around the finger 7 so that the light emitting element 2 and the light receiving element 3 sandwich the tip of the finger 7. Next, the fixing tape 9 shown in FIG. 6 is wound around the optical sensor 8 wound around the finger. The fixing tape 9 has a rectangular shape, and physical adhesive means is provided on the front surface of one end and the back surface of the other end of the tape. The optical sensor 8 is firmly fixed to the finger 7 by overlapping the backs of the ends.

When power is supplied to the lead wire 4 from the main body of the signal processing device through the connector 5, the light emitting element 2 emits light. The emitted light passes through the finger 7 and is applied to the light receiving element 3. The light receiving element 3 receives this light and gives a detection signal to the main body of the signal processing device via the lead wire 4 and the connector 5. The signal processing device detects the change in the transmittance at this time, processes the detection signal, and then calculates it to obtain a pulse value, a blood pressure value, and the like.

[Problems to be Solved by the Invention] By the way, as the light emitting element 2 used in the above-described optical sensor 8, a light emitting diode is generally used. However, the output power and the emission wavelength of the light emitting diode may change depending on the ambient temperature. On the other hand, when the optical sensor 8 is attached to a living body, for example, the finger 7, the living body side becomes ischemic or congested to lower the body temperature of the finger 7, or the blood pressure increases and the body temperature of the finger 7 rises. To do Therefore, the ambient temperature of the light emitting element 2 changes, and the output power and the measurement wavelength also change. However, in order to accurately measure a pulse value, a blood pressure value, etc., it is required that the output power and wavelength of the light emitting element 2 be kept constant.

Therefore, the main purpose of the present invention is to keep the ambient temperature of the light emitting element or the light receiving element constant even when attached to the subject,
An object of the present invention is to provide an optical sensor whose output power and wavelength do not change.

[Means for Solving the Problems] In this invention, a light emitting element and a light receiving element are arranged on a film substrate at a predetermined interval corresponding to the thickness of the subject, and the light emitting element transmits light from one side of the subject. An optical sensor that detects transmitted light on the other side by a light receiving element and detects a change in the size of absorption of transmitted light by the subject, and is close to at least one of the light emitting element and the light receiving element. A heating unit and a temperature detection unit are provided, and the heating unit heats only at least one of the light emitting element and the light receiving element so that the temperature detected by the temperature detection unit becomes constant.

[Operation] Since the optical sensor according to the present invention heats only the light emitting element or the light receiving element by the heating means so that the temperature becomes constant, the output power and wavelength of the light emitting element do not change, and It is possible to measure pulse values and blood pressure values.

[Embodiment of the Invention] FIG. 1 is a view showing an embodiment of the present invention, in particular, FIG. 1 (a) shows a plan view, and FIG. 1 (b) shows a side view. Figure (c) shows a bottom view.

Next, the configuration of an embodiment of the present invention will be described with reference to FIG. A photodiode 11 as an example of a light receiving element is provided on one end of the surface of the film substrate 10, and its lead terminal is soldered to a pattern 12 formed on the film substrate 10. A light emitting diode 14, which is an example of a light emitting element, is arranged on the other side of the surface of the film substrate 10, and its lead terminal is the film substrate 10.
It is soldered to the pattern 15 formed above. Further, a thermistor 17 as an example of temperature detecting means is arranged near the light emitting diode 14. On the left side of the pattern 15, the cable connection patterns 13, 16,
18 is formed. The pattern 13 and the pattern 12 for the photodiode 11, the pattern 16 and the pattern 15 for the light emitting diode 14, and the pattern 18 for the thermistor 17 are electrically connected by a linear pattern.

On the other hand, a heater 19 as an example of a heating unit is arranged on the back surface of the film substrate 10 at a position corresponding to the light emitting diode 14. The heater 19 is formed by forming a thin nichrome wire, for example. Heater 19
The terminals of are electrically connected to the pattern 20.

In the optical sensor configured as described above, the pattern 16 for the light emitting diode 14, the pattern 18 for the thermistor 17, the pattern 13 for the photodiode 11 and the pattern 20 for the heater 19 are connected by a cable (not shown). It is connected to the processor body. Then, the temperature in the vicinity of the light emitting diode 14 is detected by the thermistor 17, and the processing device supplies a current to the heater 19 so that the detected temperature becomes constant. This constant temperature is less noise due to heat of the light emitting diode 14, and is preferably set near the body temperature.

FIG. 2 is a view showing an example in which the thermistor 17 is attached to the heat sink 141 of the light emitting diode 14. The heat sink 141 is provided with a terminal 142 for the light emitting diode 14 and a terminal 143 for the thermistor 17.

Although the thermistor 17 is attached near the light emitting diode 14 in the above embodiment, the thermistor 17 and the heater 19 may be provided on the photodiode 11 side when the ambient temperature of the photodiode 11 becomes a problem. You may

[Advantage of the Invention] As described above, according to the present invention, the heating means and the temperature detecting means are provided in the vicinity of at least one of the light emitting element and the light receiving element so that the detected temperature becomes constant. Since the vicinity of at least one of the light emitting element and the light receiving element is heated by the above, the temperature of the light emitting element and the light receiving element is kept constant without being influenced by the temperature change of the living body. Therefore, the output power and wavelength of the light emitting element can be kept constant, and accurate biometric information can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing an example in which a thermistor is attached to a heat sink of a light emitting diode. FIG. 3 is a diagram showing an example of a conventional optical sensor. FIG. 4 is a vertical sectional view of the optical sensor shown in FIG. FIG. 5 is a sectional view when the optical sensor is attached to a finger. FIG. 6 is a perspective view of a fixing tape for fixing the optical sensor to a finger. In the figure, 10 is a film substrate, 11 is a photodiode, 12, 13, 15, 16, 18, and 20 are patterns, 14 is a light emitting diode, 17 is a thermistor, 19 is a heater, and 141 is a heat sink.

Claims (1)

[Scope of utility model registration request] 1. A light emitting element and a light receiving element are arranged on a film substrate at a predetermined interval corresponding to the thickness of a subject, and light is transmitted from one side of the subject by the light emitting element,
A light sensor that detects transmitted light on the other side by a light receiving element and detects a change in the magnitude of absorption of transmitted light by the subject, and is close to at least one of the light emitting element and the light receiving element. Heating means and temperature detecting means are provided, and at least one of the light emitting element and the light receiving element is heated by the heating means so that the temperature detected by the temperature detecting means becomes constant. An optical sensor characterized by the above.