JP2001159566A - Infrared sensor and ear type clinical thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a measurement precision and to reduce a cost by integrating an infrared sensor with a waveguide. SOLUTION: In this thermometer, a package comprises a stem base 42 and a cap 43, while the stem base 42 is mounted with an infrared detection element 46. By lengthening the cap 43, the cap 43 has a function of the waveguide. In the inner surface of the cap 43, a portion close to the infrared detection element 46 is an area 60 having high infrared emissivity, while the other portion is an area 59 having low infrared emissivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared sensor and an ear thermometer, and more particularly to a thermometer capable of measuring the temperature of the eardrum or the external auditory meatus near the eardrum so that the body temperature can be accurately measured without contact. An infrared sensor and an ear thermometer.

[0002]

2. Description of the Related Art In recent years, it has been revealed that the eardrum accurately reflects the internal temperature of the human body. Therefore, a thermometer for non-contactly measuring the temperature of the eardrum using an infrared sensor has been attracting attention in recent years. I have. According to such an ear thermometer,
In addition to being able to measure the internal temperature of the human body, there are advantages of a short measurement time of the body temperature and high measurement accuracy. Examples of such an ear thermometer include those disclosed in Japanese Patent Publication No. 5-28617 and Japanese Patent Application Laid-Open No. 8-191800.

FIG. 1 is a sectional view of an ear thermometer 1 disclosed in the former (Japanese Patent Publication No. 5-28617), and FIG. 2 is a structure of an infrared sensor 2 housed inside a housing 3 of the ear thermometer 1. FIG. The infrared sensor 2
The waveguide 4 guides infrared rays emitted from the eardrum 5 to the infrared detecting element 6 to measure the surface temperature of the eardrum 5. As shown in FIG. 2, a uniform cylindrical waveguide 4
The infrared detecting element 6 and the infrared detecting element 6 are inserted into the heat conductive block 7 from opposite sides to be integrated, and butted in the heat conductive block 7. The infrared detecting element 6 is sealed in a heat conductive block 7 by an epoxy resin 8 in order to fix the infrared detecting element 6 in a state where the infrared detecting element 6 abuts on the waveguide 4. Further, the outer periphery of a portion of the waveguide 4 exposed from the heat conduction block 7 is covered by a cover 10 including a low emissivity protection barrier layer 10a and a low heat conduction layer 10b with a space 9 therebetween.

[0004] As shown in FIG. 1, the infrared sensor 2 is housed in a housing 3 and held by studs 11, and the tip of the infrared sensor 2 projects from the tip of the housing 3. At the tip of the housing 3, a cup-shaped disposable specular 12 is attached so as to cover an exposed portion of the infrared sensor 2.

Thus, according to this ear thermometer, FIG.
When the part of the specular 12 is applied to the entrance of the external auditory meatus 13 as in the above, the infrared radiation radiated from the eardrum 5 is guided by the inner peripheral surface of the waveguide 4 and reaches the infrared detecting element 6, and the infrared detecting element 6 Is measured.

Next, FIG. 3 shows the structure of the infrared sensor 21 used in the thermometer disclosed in the latter (Japanese Patent Laid-Open No. 8-191800). In the infrared sensor 21, a light guide component 25 is formed by providing a cap-shaped portion 24 having a split groove 23 at the rear of a cylindrical waveguide 22. The waveguide 22 of the light guide component 25 is connected to the holder component 2.
6, the cap-shaped portion 24 is housed inside the holder component 26, and the infrared detecting element 28 is further housed inside the holder component 26 and fitted to the cap-shaped portion 24. After the spacer component 29 is inserted, the back opening of the holder component 26 is closed with the substrate 30, and the substrate 30 and the holder component 26 are connected with the screw 31 or the like.

[0007]

The inner surface of the waveguide used in the infrared sensor as described above is mirror-finished to propagate infrared light without loss. Emissivity cannot be made zero. Therefore, if there is a temperature difference between the waveguide and the infrared detector,
The infrared detecting element also detects infrared rays radiated from the inner surface of the waveguide, causing an error.

As one of the measures, it is important to reduce the temperature difference between the waveguide and the infrared detecting element, that is, to reduce the thermal resistance between the waveguide and the infrared detecting element.

However, in each of the above infrared sensors, the waveguide is only in contact with the infrared detecting element. It is known that when only two substances are brought into contact with each other, the microscopic contact area becomes smaller than the apparent contact area due to the surface roughness of both substances. In addition, since the cap of the infrared detecting element is generally a pressed metal product, its surface is rough. In order to increase the microscopic contact area, there are methods of increasing the contact pressure, connection by welding, and the like, but the infrared detecting element has a built-in brittle material such as silicon and has poor heat resistance. Therefore, such a method cannot be adopted.

Therefore, in the conventional infrared sensor,
The thermal resistance between the waveguide and the infrared detecting element has necessarily become considerably large, causing a measurement error of the infrared sensor.

Further, in the conventional infrared sensor,
The waveguide and the cap of the infrared detecting element are separate parts in spite of having the same cylindrical shape, which increases the number of parts and contributes to high cost. In particular, in the former infrared sensor (Japanese Patent Publication No. 5-28617),
It is necessary to fill and cure the epoxy resin 8 for sealing, which requires a long time. Further, in the latter infrared sensor (Japanese Patent Application Laid-Open No. 8-191800), the light guide component 25 on which the waveguide 22 is formed has a complicated shape, and the cost of the component itself is high. For these reasons, the cost of the conventional infrared sensor is high.

The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to integrate an infrared sensor with an infrared sensor by integrating a waveguide and an infrared detecting element. An object of the present invention is to reduce the measurement error of the thermometer, reduce the number of assembly steps, and reduce the cost.

[0013]

A first infrared sensor according to the present invention has a function of a waveguide integrally formed with a package on which an infrared detecting element is mounted.

In the first infrared sensor according to the present invention, since the functions of the package and the waveguide are integrated, it is necessary to connect and assemble the infrared detecting element and the waveguide as in the prior art. The structure of the infrared sensor can be simplified by integrating the functions of the infrared sensor and the waveguide. As a result, the assembly of the infrared sensor is facilitated, and the cost is reduced. Further, by integrating the package of the infrared sensor and the waveguide, the thermal resistance between the infrared sensor and the waveguide is reduced and the variation is reduced, so that the measurement accuracy of the infrared sensor is improved.

A second infrared sensor according to the present invention is one in which regions having different infrared emissivities are distributed on an inner surface of a package on which an infrared detecting element is mounted in order to set a predetermined viewing angle.

In the second infrared sensor according to the present invention, since the viewing angle is set by distributing regions having different infrared emissivities on the inner surface of the package, the viewing angle of the infrared sensor is maintained at a specified value. The package can be lengthened without increasing the sensor diameter while keeping the sensor. Moreover, this makes it possible to integrate the infrared sensor and the waveguide by providing the package with the function of a waveguide, so that the infrared detecting element and the waveguide are connected and assembled as in the conventional case. This eliminates the necessity, and the functions of the infrared sensor and the waveguide can be integrated to simplify the structure of the infrared sensor. As a result, the assembly of the infrared sensor is facilitated, and the cost is reduced. Further, by integrating the package of the infrared sensor and the waveguide, the thermal resistance between the infrared sensor and the waveguide is reduced and the variation is reduced, so that the measurement accuracy of the infrared sensor is improved.

In one embodiment of the second infrared sensor according to the present invention, the reflectance of a region other than the infrared incident portion may be increased at the front end of the package on the infrared incident side.

As described above, if the reflectance of the region other than the infrared ray incident portion at the front end of the package on the infrared ray incident side is made high, the radiant heat from the heat source can be reflected and cut off at the portion other than the infrared ray incident portion. In addition, the measurement accuracy of the infrared sensor can be improved by reducing the influence of radiant heat from the heat source.

In another embodiment of the second infrared sensor of the present invention, in a package for mounting an infrared detecting element, an infrared introducing window may be provided on a mounting surface of the element.

According to this embodiment, since the infrared light introducing window is provided on the mounting surface of the element, the influence of the temperature distribution of the package can be reduced, and a member such as a heat sink can be eliminated. By eliminating a member such as a heat sink, the package and the waveguide can be integrated.

Further, since the distance between the infrared detecting element and a portion other than the infrared introducing window, which is a disturbance element of the infrared detecting element, is short, the temperature difference between the two can be reduced, and the error due to the disturbance infrared light can be reduced.

Further, in still another embodiment of the second infrared sensor of the present invention, on the element mounting surface of the package on which the infrared detection element is mounted, the opposite side of the infrared detection window with respect to the infrared detection element. Is provided with a waveguide.

If the package and the waveguide are integrated as in this embodiment, the members for connecting the package and the waveguide and the assembling process can be eliminated.

In still another embodiment of the second infrared sensor of the present invention, the waveguide is surrounded by a protective tube.

If an infrared introducing window is provided on the element mounting surface, in order to secure a predetermined viewing angle, the diameter of the infrared incident window can be reduced and the diameter of the waveguide can be reduced accordingly. It can be provided directly. By integrating a protective tube for protecting the waveguide, which is a part of the package, the number of members and the number of assembly steps can be reduced. When used as an ear thermometer, the protective tube reduces the influence of heat from the external auditory canal and improves measurement accuracy.

In still another embodiment of the second infrared sensor according to the present invention, the infrared detecting element is mounted on the wiring board using the wiring board as a package, and the wiring board is connected to the wiring board by through holes formed in the wiring board. The infrared ray introduction window is provided.

In this embodiment, since the infrared detecting element can be directly mounted on the wiring board and the infrared detecting element can be packaged by the wiring board, the infrared sensor can be reduced in size and thickness, and the cost can be reduced. .

In still another embodiment of the second infrared sensor of the present invention, the mounting surface of the infrared detecting element, the mounting surface of the temperature compensating thermistor, and the mounting surface of the waveguide on the wiring board are electrically connected to each other. Electrically conductive.

According to this embodiment, the temperature difference between the mounting positions of each component can be reduced, so that the measurement accuracy can be improved, and even a package using a circuit board has characteristics equivalent to those of a metal package. can get.

An ear thermometer according to the present invention includes the infrared sensor according to the present invention, and a probe provided to cover at least a part of the infrared sensor.

According to such an ear thermometer, the effect of heat from the ear canal can be reduced by the probe section. Also,
Since the waveguide can be integrated with the infrared sensor, the cost can be reduced and the measurement accuracy can be improved.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG.
(B) is the front view and sectional view showing the structure of infrared sensor 41 by one embodiment of the present invention. FIG. 5 (a)
FIG. 5B is a cross-sectional view showing a part of the infrared sensor 41 in an enlarged manner, and FIG. The package (can package) of this infrared sensor 41 is
It is composed of a stem base 42 made of a metal such as nickel and a cap 43. An insulating sealing glass 44 is embedded in a through hole formed in a peripheral portion of a disk-shaped stem base (metal stem) 42, and the stem base 42 is penetrated through the sealing glass 44. A plurality of pin-shaped terminals 45 are inserted through the periphery of the terminal. An infrared detecting element 46 is mounted at the center of the inner surface of the stem base 42, and an output electrode 47 of the infrared detecting element 46 is provided.
The terminal 45 is connected to the terminal 45 by a bonding wire 48. A thermistor 49 for temperature compensation is mounted near the infrared detecting element 46, and the thermistor 49 and a terminal 45 are provided.
Are also connected by bonding wires 48. Thus, the infrared detecting element 46 is sealed in a package including the stem base 42 and the cap 43 (the cylindrical portion 55 and the front cover 56).

FIGS. 6A and 6B show the infrared detecting element 46.
As shown in FIG.
1, a thermopile (thermocouple array) 53 is wired between the upper surface of the recess 5 and the upper surface of the silicon substrate 50 via the heat insulating thin film 52. The hot junction region of the thermopile 53 located on the upper surface of the thin film 52 is covered with an infrared absorber 54 (for such a thermopile infrared detecting element 46, see, for example, Japanese Patent Application Laid-Open No. 2-205729). Since the infrared absorber 54 is thermally insulated by the silicon substrate 50 having a large heat capacity and the heat insulating thin film 52, when infrared rays enter the infrared detecting element 46 and are absorbed by the infrared absorber 54, 54 has a higher temperature than the silicon substrate 50. This temperature is converted into a DC voltage by the thermopile 53 and output from the output electrode 47.

The cap 43 comprises a cylindrical portion 55 having a cylindrical shape and a front cover 56 fixed to the end thereof. The cylindrical portion 55 is formed in a cylindrical shape from a metal material, and a flange 57 is provided at a rear end of the cylindrical portion 55, and the rear end is a step 58 provided on the outer peripheral portion of the stem base 42. And is integrated with the stem base 42 by resistance welding. Further, a region 59 having a low infrared emissivity and a region 60 having a high infrared emissivity are formed on the inner peripheral surface of the cylindrical portion 55. The region 60 having a high infrared emissivity is a region having a high absorptivity with a paint or the like and is formed in the vicinity of the infrared detecting element 46 over the entire length A, and the region 59 having a low infrared emissivity is a mirror surface. And is formed on the front cover 56 side over the entire length B. The region 59 having a low infrared emissivity is a portion that functions as a waveguide, and the length B corresponds to the length of the waveguide. The area 60 having a high infrared emissivity has an infrared sensor 41 depending on its length B.
Is defined.

A flange 61 is provided around the outer periphery of the distal end of the cylindrical portion 55, and a front cover 56 disposed on the front surface of the cylindrical portion 55 is fixed to the flange 61. The front cover 56 covers the periphery of an infrared incident window 62 having a function of an infrared filter that selectively transmits only infrared light of a specific wavelength with a masking portion 63.

When the infrared light enters the infrared incident window 62 at the tip of the infrared sensor 41, the incident infrared light enters the cylindrical portion 55 and is repeatedly reflected in the region 59 on the inner surface of the cylindrical portion 55 where the infrared emissivity is low. The light advances toward the infrared detecting element 46, and a part of the light is absorbed by the infrared absorber 54 of the infrared detecting element 46, and the infrared light is detected.

Next, the infrared sensor 41 having such a structure will be described.
, The inner peripheral surface of the cylindrical portion 55 is divided into a high emissivity region 60 and a low emissivity region 59 so that the infrared sensor 41
The reason why the viewing angle can be set will be described. On the inner surface of the cylindrical portion 55, the infrared rays are reflected in the low emissivity region 59,
No reflection occurs in the high emissivity region 60. When the infrared rays are reflected on the inner peripheral surface of the cylindrical portion 55, the incident angle and the reflection angle are equal. Accordingly, as shown in FIG. 4B, in the low emissivity region 59, the incident angle and the reflection angle of the infrared light at the incident end and the outgoing end of the cylindrical portion 55 are the same even if the infrared light is repeatedly reflected.

When the diameter of the inner peripheral surface of the cylindrical portion 55 is 2R and the length of the high emissivity region 60 is A, the angle α is defined as tan (α / 2) = R / A. Among the infrared rays incident from the infrared incident window 62, the infrared rays having an incident angle of α or less reach the stem base 42 while repeating reflection in the low emissivity region 59 on the inner peripheral surface of the cylindrical portion 55. On the other hand, infrared rays having an incident angle of α or more do not reach the stem base 42 because they eventually hit the high-emissivity region 60 halfway and are absorbed. In other words, by providing the high-emissivity region 60 at the end of the low-emissivity region 59, the height of the cap 43 becomes A
That is, the same characteristic of the viewing angle α as that of the conventional infrared sensor 41 can be realized.

On the other hand, in a conventional can-packaged infrared sensor, if the cap length is increased while maintaining a predetermined viewing angle α, and the cap is provided with the function of a waveguide, the infrared sensor is required. Window diameter (≒ sensor diameter) must be extremely large. This is understood from the fact that when the length of the cap is L and the inner diameter is 2R, tan (α / 2) = R / L = constant. Therefore, if the sensor diameter is increased in this way, it cannot be used inevitably for an application such as an ear thermometer that requires a sensor diameter adapted to the ear canal.

Thus, by providing the high emissivity region 60 and the low emissivity region 59 on the inner peripheral surface of the cap 43, the sensor diameter can be maintained while keeping the infrared viewing angle α at a specified value. Cap 4 without increasing
3 can be lengthened, and the package of the infrared sensor 41 and the waveguide can be integrated by providing the cap 43 with the function of a waveguide. By providing the function of a waveguide to the cap 43 of the infrared sensor 41, it is not necessary to connect and assemble the infrared detecting element 46 and the waveguide as in the related art, and the package and the waveguide are integrated. Thus, the structure of the infrared sensor 41 can be simplified. As a result, assembling of the infrared sensor 41 becomes easy, and the cost can be reduced.

In the high emissivity region 60 on the inner surface of the cap 43, the reflectivity of infrared rays is low, but since the emissivity is high, infrared radiation from the inner surface of the cap 43 is large. However, this is not a problem for the following reasons. That is, the high emissivity region 60 between the infrared detecting element 46 and the inner surface of the cap 43 is short in distance, and a metal such as nickel having high thermal conductivity is used as a material for both the cap 43 and the stem base 42. Since the stem base 42 and the cap 43 are connected by resistance welding, the thermal resistance between the two elements is low, and therefore the temperature difference between them is small. It doesn't matter.

Further, according to the infrared sensor 41 of the present invention, since the package and the waveguide are integrated, the thermal resistance between the infrared sensor 41 and the waveguide is reduced, and the variation is reduced. Thus, the measurement accuracy of the infrared sensor 41 is improved. In particular, since the cap 43 serving also as a waveguide and the stem base 42 are connected by resistance welding, the contact resistance therebetween is reduced, and the gap between the cylindrical portion 55 (waveguide) and the infrared detecting element 46 is reduced. Since the temperature difference is small, measurement accuracy can be improved.

Further, since the infrared incident window 62 is constituted by an infrared filter in which a silicon plate is coated on both sides, only infrared light of a required wavelength can be transmitted, and infrared light of a disturbance can be removed. it can.

In the infrared incident window 62, the emissivity (≒ absorptance) of the infrared filter itself is reduced by optimizing the coating and reducing the thickness. Infrared incident window 6
2 is easily affected by radiant heat because it is close to the heat source (tympanic membrane),
When the emissivity of the infrared filter is high, the filter itself absorbs infrared rays from the heat source and the filter itself rises in temperature,
This is because the infrared rays emitted from the infrared filter are absorbed by the infrared detecting element 46 and cause an error.

Further, the portion of the front cover 56 other than the infrared incident window 62 is covered with a masking portion 63 made of aluminum or the like having a low emissivity so as to reduce the influence of radiant heat from a heat source as much as possible. Note that the masking section 63 is a general sensor package, and a similar effect can be obtained when the filter is arranged on the outer surface of the package.

Next, a method for manufacturing the infrared sensor 41 will be described with reference to FIGS. FIG. 7A shows a cylindrical portion 55 whose inner surface is a mirror surface. This is made by polishing and gold plating the inner surface of a metal pipe. Next, flange processing is performed on both ends of the cylindrical portion 55 by press working (FIG. 7B).

On the other hand, both sides of the silicon wafer are coated, and a portion other than a region to be the infrared incident window 62 is covered with a masking portion 63 by aluminum vapor deposition, and is diced to produce a front cover 56. The front cover 56 thus obtained has a hexagonal shape because the silicon wafer is divided by dicing. The front cover 56 is bonded to the front end flange 61 of the tubular portion 55 (FIG. 7C).

Thereafter, the rear end of the cylindrical portion 55 is immersed in a liquid paint having a high emissivity by the length A and dried to obtain
The emissivity of the inner peripheral surface of the end of the cylindrical portion 55 opposite to the front cover 56 is reduced (FIG. 7D).

A stem base 42 having a terminal 45 is manufactured separately from the above steps (FIG. 7E), and an infrared detecting element 46 and a thermistor 49 are provided on the stem base 42.
Is mounted (FIG. 7 (f)), and the infrared detecting element 46 and the thermistor 49 are electrically connected to the terminal 45 of the stem base 42 by the bonding wire 48 (FIG. 7 (g)).

Next, the stem base 4 is attached to the flange 57 at the rear end of the cap 43 manufactured as described above.
2 are joined by resistance welding (FIG. 7 (h)) to complete the infrared sensor 41 (FIG. 7 (i)).

Next, the infrared sensor 4 having the above structure
The structure of the ear thermometer 64 using the device 1 will be described with reference to the sectional view of FIG. Reference numeral 65 denotes a circuit board on which the infrared sensor 41 is mounted with the terminal 45 inserted. Reference numeral 66 denotes a cylindrical inner block surrounding the infrared sensor 41, which is screwed to the circuit board 65. The outer diameter of the inner block 66 is narrowed at the distal end side. A probe 67 surrounds the outer periphery of the inner block 66 and is screwed to the circuit board 65. The probe portion 67 is a portion that directly contacts the external auditory canal 68, and also has a narrow outer diameter at the distal end side. An air layer 69 for heat insulation is formed between the probe 67 and the inner block 66.

When the ear thermometer 64 is inserted into the ear canal 68 as shown in FIG. 8, the tip of the infrared sensor 41 is made to face the eardrum 70. The infrared light emitted from the eardrum 70 is input to the infrared sensor 41 from the infrared incident window 62. Here, the intensity of the infrared light emitted from the eardrum 70 is a function of the temperature of the eardrum 70, and the infrared sensor 41 outputs a voltage corresponding to the intensity of the incident infrared light,
It outputs a resistance value (for ambient temperature compensation) corresponding to the temperature of the infrared sensor 41 itself. The output of the infrared sensor 41 is subjected to arithmetic processing by an arithmetic processing circuit mounted on the circuit board 65, and the temperature (body temperature) of the eardrum 70 is displayed on a liquid crystal display (not shown).
Is displayed.

(Second Embodiment) FIG. 9 is a perspective view of an infrared sensor 71 according to another embodiment of the present invention, FIG. 10 is a sectional view of the infrared sensor 71, and FIG. 11 is a sectional view taken along line YY of FIG. FIG. FIGS. 12A and 12B are a cross-sectional view and a front view showing the vicinity of an infrared detecting element 46 mounted on the stem base 42. In this infrared sensor 71, as shown in FIGS. 12 (a) and 12 (b), a concave portion 72 is provided at the center of the front surface of a metal stem base 42 provided with a plurality of input / output terminals 45. In the center of the bottom surface of the concave portion 72, an infrared ray introducing window 73 penetrating the stem base 42 is opened. The infrared detecting element 46 having the same structure as that described in the first embodiment is similar to that shown in FIGS.
As shown in (a) and (b), it is mounted on the stem base 42 so as to be accommodated in the recess 72, and the thermistor 49 is mounted near the infrared detecting element 46. The electrode of the infrared detecting element 46 and the thermistor 49 are connected to the terminal 45 by a bonding wire 48.

In this embodiment, the stem base 4
2. A package is constituted by the cap 43, the waveguide 74, and the protection pipe 75. As shown in FIGS. 9 and 10, the end face of the waveguide 74 is joined to the back surface of the stem base 42 so as to surround the infrared light introducing window 73, and is further protected so as to surround the waveguide 74 with a space therebetween. The end face of the pipe 75 is joined to the back of the stem base 42. The waveguide 74 guides infrared rays to the infrared detecting element 46, and the protective pipe 75 reduces the influence of disturbance. Further, the front surface of the stem base 42 is covered by a cap 43 having a relatively low height.

In the infrared sensor 71 having such a structure, infrared light is introduced from the waveguide 74 on the back surface. The infrared light that has entered the waveguide 74 reaches the stem base 42 while repeating reflection on the inner surface of the waveguide 74,
The light is guided to the infrared detecting element 46 through the infrared introducing window 73 of the stem base 42. The infrared light guided to the infrared detection element 46 passes through the silicon substrate 50 of the infrared detection element 46 and is absorbed by the infrared absorber 54. At this time, the silicon substrate 50 of the infrared detecting element 46 functions as a filter. Since the infrared absorber 54 is thermally insulated from the silicon substrate 50 by the heat insulating thin film 52, the temperature of the infrared absorber 54 that has absorbed infrared rays rises as compared with the silicon substrate 50. The infrared sensor 71 converts the increased temperature into a DC voltage by the thermopile 53 and outputs the DC voltage from the electrodes.

Here, the inner surface of the waveguide 74 is mirror-finished over its entire length and has a low infrared emissivity, so that there is little reflection loss and diffusion of infrared light, and little infrared radiation from the waveguide 74 itself. It has a configuration.

On the other hand, infrared rays entering the infrared absorber 54 of the infrared detecting element 46 are radiated from the inner surface of the infrared introducing window 73 of the stem base 42 and the element mounting surface of the stem base 42 in addition to the waveguide 74. Some are done.
These infrared rays are essentially error components, but do not pose a problem for the following reasons. That is, an infrared detecting portion (a portion including the heat insulating thin film 52, the thermopile 53, and the infrared absorber 54) of the infrared detecting element 46 and a portion that emits infrared light as an error element (the infrared introducing window 73 of the stem base 42).
Is extremely small, the temperature is almost the same, and the temperature difference is negligible.

The infrared detecting portion of the infrared detecting element 46 (the portion including the heat insulating thin film 52, the thermopile 53, and the infrared absorbing member 54), the inner surface of the infrared introducing window 73 of the stem base 42, and the device mounting surface of the stem base 42 The reason for the low thermal resistance is that the infrared detecting element 46 is silicon, and the stem base 42 is metal.
This is because the distance between the infrared detection element 46 and the stem base 42 is short (the thickness of the infrared detection element 46 is several hundred μm, and the thickness of the stem base 42 is only about 1 mm).

In a conventional can-package type infrared sensor 81 as shown in FIG.
Disturbance infrared rays incident on the infrared absorber 4 are infrared rays emitted from the inner surface of the cap 82 and the filter 83. In the case of this infrared sensor 81, the distance between the inner surface of the cap 82 or the filter 83 and the infrared detecting element 84 is
Since the thickness of the cap 82 is very large compared to the infrared sensor 71 of the present invention and the thickness of the cap 82 cannot be made thicker than the limit of processing (pressing), the cap 82 and the filter 83
The thermal resistance between the sensor and the infrared detecting element 84 is large, and therefore, the temperature difference is also large. Therefore, infrared rays from the cap 82 and the inner surface of the filter 83 cannot be ignored as errors. As a countermeasure, it is necessary to cover the entire sensor with a heat sink having a large heat capacity.
617), and the cost of parts and assembly was a problem.

On the other hand, in the infrared sensor 71 of the present invention, although a temperature difference occurs between the stem base 42 and the cap 43, the infrared sensor 71 detects infrared rays to reduce the influence of disturbance infrared rays radiated from the inner surface of the cap 43. An aluminum thin film is formed on the surface of the infrared absorber 54 of the element 46 by vapor deposition. Since the emissivity of aluminum is low, the structure is not affected by the radiation from the inner surface of the cap 43.

In the infrared sensor 71 of this embodiment, since the protective pipe 75 is provided outside the waveguide 74 and joined to the stem base 42, the temperature distribution of the waveguide 74 can be made uniform. it can. The inner surface of the waveguide 74 is specular, but its reflectivity cannot be made completely zero. If there is a temperature difference between the inner surface of the waveguide 74 and the infrared detecting element 46, the infrared detecting element 46 will detect an infrared ray radiated from the inner surface of the waveguide 74 as an error. For example, considering the case where such an infrared sensor 71 is applied to an ear thermometer, when there is no protective pipe 75,
The temperature of the waveguide 74 rises by the following mechanism, and a temperature distribution occurs. That is, the temperature of the probe portion of the ear thermometer rises due to radiation from the ear canal and heat conduction, heat is transferred by radiation from the inner surface of the probe portion whose temperature has risen to the waveguide 74, and the temperature of the waveguide 74 also rises. . At this time, since the heat transfer in each part is not uniform, a temperature distribution also occurs in the waveguide 74 itself. In contrast, the infrared sensor 7 of this embodiment
In 1, the heat insulating layer of air is doubled by interposing the protection pipe 75 between the probe part and the waveguide 74, and the amount of heat transfer is reduced. The protective pipe 75 is made of a material having a high thermal conductivity, such as nickel, in order to make its temperature distribution uniform, and is made thick to increase its heat capacity. For this reason, the temperature rise and the temperature distribution of the waveguide 74 are efficiently made uniform.

In the infrared sensor 71, the inner surface of the waveguide 74 has a higher infrared emissivity, and the inner surface of the infrared introducing window 73 has a region with a lower infrared emissivity, as shown in FIG. As shown in FIG. 7, the viewing angle α of the infrared sensor 71 is determined by the depth (thickness) of the infrared introducing window 73, and for the same reason as in the first embodiment, the waveguide 7
4 can be integrated with the stem base 42.
Therefore, the structure of the infrared sensor 71 is simplified, the assembly is easy, and the cost is low. Further, the waveguide 74
The thermal resistance between the base and the stem base 42 is also reduced, and the measurement accuracy is improved.

Further, the protection pipe 75 is connected to the stem base 4.
2 can be integrated for the following reason. The field of view as the infrared sensor 71 is determined by moving the infrared absorbing body 54 of the infrared detecting element 46 from the infrared introducing window 73 of the stem base 42.
Is determined by the distance to the back surface and the window diameter. When a window is provided in the conventional cap 43, the distance between the infrared absorber 54 and the window is increased in order to secure the thickness of the filter and the space necessary for wire bonding, and therefore, a predetermined viewing angle is required. , The diameter of the window must be increased, and the diameter of the waveguide 74 increases accordingly. In contrast, in the case of the infrared sensor 71, the distance between the infrared absorber 54 and the infrared introducing window 73 is different from the stem base 4
Since only the sum of the thickness of the element mounting portion 2 and the thickness of the infrared detecting element 46, the window diameter can be reduced, and the diameter of the waveguide 74 can be reduced. If the diameter of the waveguide 74 is reduced, the protection pipe 75 can be integrated with the stem base 42 because there is a space for mounting the protection pipe 75 accordingly.

Next, a method of manufacturing the infrared sensor 71 will be described with reference to FIGS. First, terminal 4
5 is prepared, and a waveguide 7 is provided.
4 is brazed to the stem base 42 (FIG. 13).
(A)). The emissivity of the inner surface of the waveguide 74 is reduced by previously plating the inner surface of the metal pipe with Au. Next, a waveguide 74 is provided on the back surface of the stem base 42.
Through a protective pipe 75 so as to surround
(B)), the end face of the protection pipe 75 is brazed to the stem base 42 (FIG. 13C). Thereafter, the infrared detecting element 46 and the thermistor 49 are mounted on the stem base 42 (FIG. 13D). When mounting the infrared detecting element 46, airtightness is ensured by applying an adhesive around the infrared introducing window 73. This adhesive uses an adhesive containing a silver filler to reduce the thermal resistance between the infrared detecting element 46 and the stem base 42 and to electrically connect the thermistor 49 and the stem base 42. .
Next, the mounted infrared detecting element 46 and the thermistor 4
9 is electrically connected to the terminal 45 by a bonding wire 48 (FIG. 13E). Finally, the cap 43 is joined to the stem base 42 by resistance welding (FIG. 13).
(F)) The infrared sensor 71 is completed.

Next, an ear thermometer 76 using the infrared sensor 71 is shown in FIG. In this ear thermometer 76, a protective pipe 75 is inserted into a hole 78 of a circuit board 77 from the back.
And the infrared sensor 71 is mounted on the circuit board 77, and the outer peripheral portion of the protection pipe 75 is covered with the probe section 80 via the air layer 79 on the front side of the circuit board 77, and the probe section 80 is screwed to the circuit board 77. I'm stopping.

When the ear thermometer 76 is inserted into the external auditory canal 68, the tip of the infrared sensor 71 faces the eardrum 70. Then, the infrared light radiated from the eardrum 70 is input to the infrared sensor 71.
Here, the intensity of the infrared ray radiated from the eardrum 70 is
As a function of the temperature of 0, the infrared sensor 71 outputs a voltage corresponding to the intensity of the incident infrared light and a resistance value (for ambient temperature compensation) corresponding to the temperature of the infrared sensor 71 itself.
The output of the infrared sensor 71 is subjected to arithmetic processing by an arithmetic processing circuit mounted on the circuit board 77, and the temperature (body temperature) of the eardrum 70 is displayed on a liquid crystal display unit (not shown).

The second embodiment can also be applied to a device in which the viewing angle cannot be controlled by changing the infrared emissivity in the package.

(Third Embodiment) FIGS. 16A and 16B are a sectional view and a plan view showing an infrared sensor 91 according to still another embodiment of the present invention. In this embodiment, instead of mounting the infrared detecting element 46 in a package, the printed circuit board 92 (or a three-dimensional printed circuit board (MID) may be used) as a package and the infrared sensor 91 is integrated in the printed circuit board 92. Incorporated.

As shown in FIG. 16 (a), this printed wiring board 92 is a two-layer laminated substrate in which a first layer 92a and a second layer 92b are laminated, and a part of the second layer 92b is formed. The mounting space 93 is formed in the printed wiring board 92 by opening. In addition, 94 is the printed wiring board 9
2, a signal line pattern of the first layer 92a, 95 is a ground (GND) pattern of the printed wiring board 92, 96 is a signal line through hole of the printed wiring board 92, and 97 is a ground (GND) through hole of the printed wiring board 92. is there. In the mounting space 93, the infrared detecting element 46 and the thermistor 49 are mounted on the first layer 92a,
The infrared detecting element 46 and the thermistor 49 are connected to each signal line pattern 94 by a bonding wire 48.
Further, an infrared light introduction window 73 is opened in the first layer 92a so as to face the center of the lower surface of the infrared light detection element 46, and the printed wiring board 92 is surrounded by the infrared light introduction window 73.
The waveguide 74 is soldered to the ground pattern 95 on the lower surface of the substrate. The ground pattern 95 to which the waveguide 74 is attached is electrically connected to the ground pattern 95 on the upper surface of the first layer 92a.

The mounting space 93 containing the infrared detecting element 46 and the thermistor 49 is closed by a nickel-plated steel lid 98 to protect the internal elements from the surrounding environment. This lid 98 is joined to the conductor pattern on the upper surface of the second layer 92b by soldering. Reference numeral 99 denotes an electronic component such as an IC, a resistor, and a capacitor mounted on the printed wiring board 92.

As described above, the ground patterns 95 formed on the upper surface and the lower surface of the first layer 92a are electrically connected to each other, so that the detection elements (infrared ray introducing window 73, infrared ray detecting element 46, thermistor 49) are connected. , The thermal resistance can be reduced and the thermal coupling can be increased. Further, the infrared detecting element 4
If there is a temperature difference between 6 and the inner surface of the infrared light introducing window 73 and the inner surface of the waveguide 74, infrared rays emitted from the infrared light introducing window 73 and the waveguide 74 may be detected as an error. Since the temperature difference between the infrared detecting element 46 and the thermistor 49 may cause an error in the correction of the ambient temperature, such a risk is prevented by reducing the thermal resistance between the three elements.

The conductor pattern of the printed wiring board 92 is made of copper having a high thermal conductivity (plated with Au plating for wire bonding), and a thicker one is used. By using a solid pattern that also serves as a ground layer, the thermal resistance is reduced as much as possible.

The ground pattern 95 on the upper surface of the first layer 92a and the ground pattern 95 on the lower surface are connected via a ground pattern 95 (through hole) formed on the inner surface of the infrared light introducing window 73. Further, since this pattern surface is not subjected to a resist treatment unlike a general printed wiring board, the surface is in an Au-plated state. Since the Au-plated surface has a low surface emissivity, it is less susceptible to disturbance infrared rays, thus contributing to the improvement of the accuracy of the infrared sensor 91.

In the infrared sensor 91, the output of the infrared detecting element 46 and the output of the thermistor 49 are transmitted through the bonding wire 48 to the signal line pattern 94 on the first layer 92a and the through hole 96 of the second layer 92b. The signal is guided to a circuit portion on the layer 92b and subjected to signal processing.

The one terminal 45 of the thermistor 49 is connected to the ground pattern 95 via a conductive adhesive, which is a mounting material, and is guided to a circuit section through a through hole 97.

According to the infrared sensor 91 having such a configuration, it is advantageous for modularizing and downsizing the sensor. In addition, a can package is not required, and can be supplied at low cost. Moreover, even if a can package is not used, a thermally important portion can be handled by the conductor pattern of the printed wiring board 92, and the characteristics of the infrared sensor 91 can be secured. Also, the method of manufacturing the printed wiring board 92 on which the infrared sensor 91 is mounted is the same as the method used for bare chip mounting and is general, so that it can be manufactured at low cost.

In this embodiment, a coating material or the like having a high light absorbing property is applied to the inner surface of the infrared light introducing window (through hole) so that the infrared emissivity becomes higher than that of the inner surface of the waveguide. The viewing angle can be controlled by the infrared light introducing window 73. However, the third embodiment can also be applied to a configuration in which the viewing angle cannot be controlled by changing the infrared emissivity in the package.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the structure of a conventional ear thermometer.

FIG. 2 is a sectional view of the infrared sensor according to the first embodiment;

FIG. 3 is a cross-sectional view of an infrared sensor used in another conventional ear thermometer.

FIGS. 4A and 4B are a front view and a sectional view showing a structure of an infrared sensor according to an embodiment of the present invention.

5A is a partially enlarged cross-sectional view of the infrared sensor, and FIG. 5B is a cross-sectional view taken along line XX of FIG. 5A.

FIGS. 6A and 6B are a plan view and a cross-sectional view of an infrared detection element.

FIGS. 7A to 7I are cross-sectional views illustrating steps for manufacturing the infrared sensor according to the first embodiment.

FIG. 8 is a sectional view of an ear thermometer using the infrared sensor according to the first embodiment.

FIG. 9 is a perspective view showing a structure of an infrared sensor according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view of the infrared sensor.

FIG. 11 is a sectional view taken along line YY of FIG. 10;

12A and 12B are a cross-sectional view and a front view showing the vicinity of an infrared detecting element mounted on a stem base.

13 (a) to 13 (f) are cross-sectional views showing steps of manufacturing the infrared sensor according to the first embodiment.

FIG. 14 is a sectional view of an ear thermometer using the infrared sensor according to the first embodiment.

FIG. 15 is a sectional view of a conventional can-package type infrared sensor.

FIG. 16A is a cross-sectional view showing a structure of an infrared sensor according to still another embodiment of the present invention, and FIG. 16B is a plan view of a first layer thereof.

[Explanation of symbols]

 41 Infrared Sensor 42 Stem Base 43 Cap 46 Infrared Detector 49 Thermistor 55 Tube 59 Low Infrared Emissivity Area 60 High Infrared Emissivity Area 62 Infrared Incident Window 64 Ear Thermometer 67 Probe 71 Infrared Sensor 74 Waveguide 75 Protection pipe

Claims (9)

[Claims] 1. An infrared sensor in which the function of a waveguide is formed integrally with a package on which an infrared detecting element is mounted. 2. An infrared sensor, wherein regions having different infrared emissivities are distributed on an inner surface of a package on which an infrared detecting element is mounted to set a predetermined viewing angle. 3. The infrared sensor according to claim 2, wherein a reflectance of a region other than an infrared ray incident portion is increased at an end of the package on an infrared ray incident side. 4. The infrared sensor according to claim 2, wherein in a package on which the infrared detecting element is mounted, an infrared introducing window is provided on a mounting surface of the element. 5. A waveguide provided on an element mounting surface of a package on which the infrared detecting element is mounted, on a surface opposite to the infrared detecting element with respect to the infrared light introducing window. 5. The infrared sensor according to 4. 6. The infrared sensor according to claim 5, wherein the waveguide is surrounded by a protective tube. 7. The wiring board according to claim 4, wherein the infrared detecting element is mounted on the wiring board using the wiring board as a package, and the infrared light introducing window is provided in the wiring board by through holes formed in the wiring board. An infrared sensor as described. 8. The wiring board according to claim 7, wherein the mounting surface of the infrared detecting element, the mounting surface of the temperature compensating thermistor, and the mounting surface of the waveguide on the wiring board are electrically connected to each other. Infrared sensor. 9. An ear thermometer comprising: the infrared sensor according to claim 1; and a probe provided so as to cover at least a part of the infrared sensor.