JPH11351959A - Can with window material, method for fixing and temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature sensor for easily positioning a window material without reducing an effective diameter of a light passing a window hole. SOLUTION: The can 13 is mounted to cover an infrared detecting element 11 loaded on a metal stem 10. A window hole 13c is provided at a top surface 13b of the can, and an infrared transmission filter 18 is mounted at the top surface to block the hole. At this time, an endless metal thin film 20 is vapor deposited on a peripheral edge of the material, the film 20 is soldered to the top surface via a solder 19 between the film 2 and the top surface, thereby integrating them while keeping an airtightness therebetween. The filter is moved to a central position by means of a surface tension generated in the case of liquefying the solder, thereby automatically aligning it. Since the solder is existed only at a metal thin film forming position, it is not extended into the window material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can with window material, a fixing method, and a temperature sensor.

[0002]

2. Description of the Related Art As one type of non-contact type temperature sensor, there is an infrared sensor for detecting infrared rays emitted from an object. As is well known, objects emit infrared radiation depending on the absolute temperature. Therefore, the temperature can be measured from the detected infrared light.

An infrared sensor has various structures. For example, a thermocouple is used as an element for generating heat by receiving infrared rays emitted from an object, converting the heat into an electric signal and measuring the temperature. Some use a thermopile element. FIG. 1 shows a specific structure of an infrared sensor using the thermopile element.

First, a thermopile element 1 is connected to a metal stem 2.
The thermopile element 1 is fixed on the top by die bonding.
And the lead pin 3 provided on the metal stem 2 are electrically connected by wire bonding or the like. Then, a can 4 is mounted on the upper surface of the metal stem 2 so as to cover the thermopile element 1. A window hole 4b through which infrared light passes is formed on the top surface 4a of the can 4, and an infrared transmission filter 5 made of Si or the like is adhered to a region where the window hole 4b is formed from the inside.

[0005] As a result, only infrared rays pass through the window hole 4b (infrared transmitting filter 5), enter the inside of the can 4, and reach the thermopile element 1, so that the thermopile element 1 generates heat by the received infrared rays and generates heat. The heat is converted into an electric signal and output. Therefore, the temperature is determined based on the electric signal.

The can 4 and the infrared transmitting filter 5
Is usually performed through a process as shown in FIG. That is, first, a resin adhesive 6 such as an epoxy adhesive is applied to the inner peripheral edge of the top surface 4a of the can 4 (FIG. 3A). Next, the infrared transmission filter 5 is inserted from the inside of the can 4, and is brought into contact with the top surface 4a in a pressurized state. As a result, the infrared transmission filter 5 is fixed to the can 4 via the resin adhesive 6 as shown in FIG.

[0007]

However, the connection structure between the can and the infrared transmitting filter in the above-mentioned conventional sensor has the following problems.

[0008] That is, the resin adhesive is dripped. Moreover, it is necessary to apply the adhesive to some extent to ensure the adhesion, and when the infrared transmitting filter 5 is pressed, the resin adhesive 6 is crushed and tends to spread. At this time, if it tries to spread outward, it hits the inner wall surface of the can 4, so that it protrudes toward the free inside. Then, as shown in FIG.
The inner diameter R2 of the resin adhesive 6 is smaller than the inner diameter R1 of the window hole 4b, and the effective diameter for transmitting infrared rays is smaller. That is, the infrared light that has passed near the inner peripheral edge of the window hole 4b hits the protruding resin adhesive 6, and
Any further progress will be stopped and you will be narrowed down.
Therefore, the amount of received light is reduced, and the measurement sensitivity is reduced.

Further, when the infrared transmitting filter 5 is pressed against the top surface 4a, the infrared transmitting filter 5 moves sideways, and the thickness of the resin adhesive 6 does not necessarily cause the infrared transmitting filter 5 to move.
May not be parallel. That is, misalignment is likely to occur, and the yield is poor. In addition, the lateral displacement can be dealt with by making the outer diameter of the infrared transmission filter 5 sufficiently larger than the inner diameter of the window hole 4b (for example, to be substantially equal to the inner diameter of the top surface 4a of the can 4). Since the portion in contact with the surface 4a is a useless portion for the original filter function, the material cost increases, and the number of filters that can be obtained from one substrate is reduced, resulting in an increase in cost. Furthermore, even if it is so large, the top surface 4a
However, the problem that the adhesive is adhered in an inclined manner without being parallel is not solved.

Further, the resin adhesive 6 has poor airtightness, and particularly has a problem of moisture permeability, which causes a sensor failure. Furthermore, since it takes time (about 1 hour) for the resin adhesive 6 to be cured, not only is the productivity low, but also the infrared transmission filter 5 is displaced by the time the adhesive is cured. There is a possibility that it will occur. Furthermore, since the adhesive diameter is substantially equal to the nozzle diameter of the device for applying the adhesive, the application itself becomes difficult.

Japanese Patent Application Laid-Open No. 5-288603 discloses a technique in which a window material is bonded to a window hole provided in a can of a sensor having a built-in pyroelectric element by using silver solder. . However, this publication does not disclose a detailed configuration and adheres under a reducing atmosphere, which complicates the processing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to solve the above-mentioned problems, to be easily carried out in a normal atmosphere, and to pass through a window hole. An object of the present invention is to provide a can with a window material, a fixing method, and a temperature sensor that can easily position a window material without reducing an effective area of light and can reduce the amount of use (external dimensions) of the window material. . Another object of the temperature sensor is to reduce the size of the sensor.

[0013]

In order to achieve the above-mentioned object, a can with a window material according to the present invention comprises a cap-shaped can having a window hole on a top surface and the top can be closed so as to cover the window hole. An endless metal thin film is vapor-deposited on a periphery of the window material, and is interposed between the metal thin film and the top surface. The metal thin film and the top surface are brazed and integrated by a brazing material (claim 1).

Preferably, the dimension and shape of the inner peripheral edge of the metal thin film are equal to or larger than the dimension and shape of the inner peripheral edge of the window hole.

Further, in the fixing method according to the present invention, there is provided a fixing method for fixing a light-transmitting window material to the top surface of a cap-shaped can having a window hole on the top surface, wherein the entire periphery of the window material is provided. A metal thin film is deposited on the substrate. Next, a washer-type solder is arranged between the top surface and the metal thin film. Then, the window material is fixed to the can by heating and then cooling the solder and bonding the top surface and the metal thin film (claim 3).

Further, in the temperature sensor according to the present invention, the stem having the infrared detecting element mounted thereon and the can with the window material according to claim 1 or 2 attached to the stem so as to cover the infrared detecting element. Prepare. The window member is an infrared transmission filter, and the infrared light transmitted through the infrared transmission filter is detected by the infrared detection element.

[0017] Preferably, the metal stem has a thick base serving as a mounting surface of the infrared transmission filter;
A thin flange protruding outward from the periphery of the base, and a positioning plane (corresponding to “positioning surface 10C” in the embodiment) on the outer peripheral side surface of the base.
(Claim 5).

Since the metal thin film is formed on the periphery of the light-transmitting window material, the brazing material does not adhere to the window material but brazes the metal thin film to the can. Since the brazing material has high airtightness and low moisture permeability, airtight reliability is improved. Further, the brazing material is liquefied at the time of heating, and the position of the window material is automatically corrected by the surface tension of the brazing material generated at this time. Therefore, a gap does not occur between the window hole and the window material without using a member having a size that is too large for the window hole.

In addition, since the metal thin film and the can are brazed, the work can be performed in an ordinary atmosphere, and since the brazing material can be placed, the work is simpler than the conventional application of a resin adhesive. Therefore, workability is improved. Moreover,
Since the brazing is completed in a time (about 10 minutes) sufficiently shorter than the curing time (about 1 hour) of the resin adhesive, the working efficiency is improved. Further, when washer solder is used as the brazing material as in claim 3, workability is further improved.

Further, in the present invention, since the interposition position of the brazing material coincides with the formation region of the metal thin film, there is no possibility that the brazing material unnecessarily protrudes to the window hole side. Therefore, an effective area as designed can be secured. According to the second aspect of the present invention, the area of light that can pass through the can is equal to the opening area of the window, so that the amount of light that can be transmitted can be increased. * Definition of terms "Can" is a container for covering the light receiving element, etc. when packaging the light receiving element, the light emitting element and other parts. And in this invention, especially the window hole for light to pass through was provided in the top surface.

The "window material" is a material for closing a window hole opened in the can. For example, in the case of a non-contact type temperature sensor of the infrared detection type, the can is provided with a window through which infrared rays pass,
As a material for closing the window, a filter or a lens made of a material that transmits infrared rays is used. Note that the window material is not limited to one that exerts any action or influence on light to be transmitted as illustrated, and may be an optically transparent glass plate or the like provided for maintaining airtightness. Good.

The "brazing material" is a material used for brazing, and includes "wax (hard solder)" and "solder (soft solder)". Actually, solder is mainly used in consideration of the heating temperature.

The "top surface" refers to a surface opposite to the side where the can is attached to the stem, and the side on which a window hole through which light passes is the top surface referred to in the present invention. In other words, even if it is located on the lower side or the like depending on the direction of the actual use situation, if it satisfies the above conditions, it corresponds to the top surface according to the present invention.

[0024]

FIG. 3 shows a first embodiment of the present invention. The non-contact type temperature sensor fixes the infrared detecting element 11 on the upper surface of the metal stem 10 and
The metal stem 1 is set so as to cover the infrared detecting element 11.
A cylindrical metal can 13 with an open lower end is mounted on the upper surface of the “0”.

As the infrared detecting element 11, a thermopile element is used. This thermopile element is a device that generates heat by receiving infrared rays emitted from an object, converts the heat into an electric signal, and measures the temperature. An insulating thin film is formed on the surface of a semiconductor substrate, and a heterogeneous film is formed on the insulating thin film. A thermocouple disposed in contact with a metal or semiconductor is formed, and a semiconductor substrate layer below a central region of an insulating film where a contact portion exists is removed. In this thermopile element, when infrared rays are incident and the contact portion is heated, an electromotive force is generated between dissimilar metals or semiconductors by the Seebeck effect, and the temperature is measured by the electromotive force.

The infrared detecting element 11 is fixed at the center of the upper surface of the metal stem 10 by die bonding. On the other hand, lead pins 16 are attached to the metal stem 10 at 90-degree intervals. Three of them are metal stems 1
0, and the upper end protrudes from the upper surface of the metal stem 10. Then, the electrode of the infrared detecting element 11 is electrically connected to the lead pin 16 by a wire bonding 17 or the like. Further, the flange portion 10a formed around the metal stem 10 and the flange portion 13a formed at the lower edge of the can 13 are brought into contact with each other and joined by resistance welding.

The can 13 has a cylindrical main body with an open lower end, and a window hole 13c is formed in the center of the top surface 13b. Then, the infrared transmission filter 18 is attached from the lower surface side of the top surface 13b so as to close the window hole 13c. As a result, of the external light, only infrared light passes through the infrared transmission filter 18 and irradiates the infrared detection element 11 mounted inside the can 13. Infrared detector 1
1 generates an electric signal corresponding to the received infrared light, so that the signal can be output through the lead pin 16 and taken into an external device (not shown) so that the temperature can be measured. Reference numeral 21 in FIG. 3 denotes a thermistor, and reference numeral 22 denotes a positioning projection. Such a configuration is basically the same as that of a conventional sensor.

Here, in the present invention, the infrared transmission filter 1 is used.
8 is attached to the can 13 using solder 19. At this time, a ring-shaped metal thin film 20 having good wettability with solder is formed on the outer periphery of the infrared transmission filter 18, and bonding using the solder 19 is performed in a region where the metal thin film 20 is formed. That is, the solder 19 adheres to the top surface 13b of the can 13 and the metal thin film 20, and the infrared transmission filter 18 is soldered via the metal thin film 20, and the surface of the infrared transmission filter 18 The solder 19 is not directly bonded.

To explain in more detail according to the manufacturing process, first, as shown in FIG. 4A, an infrared transmitting filter 18 having an antireflection film made of Si or the like is prepared, and a Cr / Au layer is formed on the outer peripheral edge thereof. A ring-shaped metal thin film 20 having a predetermined width is formed. The metal thin film 20 is formed by first depositing Cr on the entire surface of the filter, depositing Au on the filter to form a thin film having a two-layer structure, and then patterning the resultant using a lithography technique or the like. Can be formed. Of course, after performing the patterning at the stage of the wafer of the filter, the filter having the metal thin film as shown in the drawing is manufactured by cutting out.

The dimensions and shape of the metal thin film 20 are as follows.
The width is set to a size that can maintain sufficient adhesive strength. The inner diameter R3 is equal to or larger than the inner diameter of the window hole 13c formed in the can 13 (in the illustrated example, it is increased). Although the outer diameter of the metal thin film 20 is equal to the outer diameter of the infrared transmission filter 18 in the illustrated example,
The outer diameter of the metal thin film 20 may be smaller. However,
The region where the metal thin film 20 is formed serves as a margin for actual soldering, and the portion outside the window hole 13c, that is, the portion facing the top surface 13b, does not function as an infrared transmission filter. Since it is a useless area, it is preferable to make it match as shown in the figure because it can be used efficiently.

As shown in FIG. 4B, a washer-type Sn-Pb solder 19 is disposed between the infrared transmitting filter 18 and the can 13 processed as described above, and the two are superposed. For example, by passing through a reflow furnace with the top surface 13b side down, heating and cooling are performed to perform a reflow soldering process. Note that the atmosphere during the soldering process can be performed under a normal atmosphere. This is the C of the metal thin film 20.
This is because Si (the surface of the filter) and the metal are bonded using the u / Au layer.

Thus, as shown in FIG. 5A, the can 13 and the infrared transmitting filter 18 are bonded. Then, due to the surface tension generated when the solder 19 is heated and liquefied, the infrared transmission filter 18 is attached to the top surface 1 of the can 13.
It is automatically moved to the center of 3b. Therefore, the window hole 13c
And the center of the infrared transmission filter 18 coincides with each other, and is bonded by the solder 19 having good airtightness over the entire circumference, so that the airtight reliability is stabilized and improved. Further, since such positioning is automatically performed, the external dimensions of the infrared transmission filter 18 do not need to be made larger than necessary as in the conventional case, and the number of filters that can be obtained from one wafer increases, and the cost increases. It is cheap.

Further, the inner diameter R of the window hole 13c of the can 13
Since the inner diameter R3 of the metal thin film 20 is larger than 1, the position of the inner peripheral surface of the solder 19 is outside the position of the inner peripheral surface of the window hole 13 c as shown in FIG. . That is, since the solder 19 and the infrared transmission filter 18 are not bonded, the solder 19 does not protrude inside the metal thin film 20. Accordingly, as shown in FIG. 5A, the entire window hole 13c has an effective diameter for transmitting infrared light, and the infrared light passing through the window hole 13c proceeds into the can 13 as it is. Therefore,
The amount of light received by the infrared detecting element mounted inside the can 13 increases, and the detection sensitivity improves.

Further, in this embodiment, since the solid and fixed size washer solder 19 is used, not only the workability of interposing the solder 19 between the can 13 and the infrared transmission filter 18 is improved, but also the solder 19 is used. Since the amount is also constant, there is no problem such that the amount is too large and the amount is too small, and the amount is too small, such as a decrease in adhesive strength and deterioration in airtightness. Furthermore, Sn-
It is preferable to use a low melting point solder such as Pb solder because there is no damage to the filter. Furthermore, since the time required for the reflow process is only a few minutes, the processing time can be reduced. A sensor is formed by bonding the filter can 13 thus formed to the metal stem 10 by resistance welding or the like.

That is, the sensor having the above-described configuration can be used for detecting various temperatures, and is used in an ear-type thermometer as one of the usage modes. This ear thermometer measures the temperature of the eardrum, and its schematic structure is as shown in FIG. That is, the temperature sensor 27 having the above configuration is installed inside the front of the apparatus main body 25, and the temperature sensor 2
A probe 26 is attached to the front surface of the device main body 25 so as to face the device 7, so that the probe 26 can be inserted into the ear. Further, a waveguide 29 is provided inside the probe 26 for collecting infrared rays radiated from the eardrum 28.

Thus, the infrared light from the eardrum 28 is guided to the temperature sensor 27 via the waveguide 29, and the temperature in the device in the device main body 25 is determined based on a signal corresponding to the infrared light output from the temperature sensor 27. Is calculated and displayed.

FIG. 6 shows a main part of the second embodiment of the present invention. In the present embodiment, the structure of the metal stem 10 is improved on the premise of the first embodiment. That is, although not shown in FIG. 6, the infrared transmitting filter 18, which is a characteristic feature of the first embodiment, is integrally bonded to the can 13 via a metal thin film and solder, and 6 is mounted on the metal stem 10 and sealed by resistance welding or the like in the present embodiment.

As is well known, a metal stem is
Normally, a metal base provided with a projection (reference numeral 22 in FIG. 3) on an outer peripheral portion is used, and a through hole for mounting a lead pin is positioned by using the projection as a reference. The pins are bonded and fixed with glass or the like. However, these protrusions increase the size of the metal stem and the size of the non-contact temperature sensor. As a result, since it was impossible to make the sensor size large enough to pass through the ear canal, the sensor 27 was arranged outside the ear canal as shown in FIG. I was trying to do it. In this method, the radiation of the infrared light from the waveguide itself is not only a cause of errors, but also the cost of the thermometer increases because components such as the waveguide are expensive.

Therefore, in the present embodiment, the sizes of the infrared detecting elements 11 such as thermopile elements are equal and the sensor size is reduced. That is, the protrusion on the outer peripheral portion of the metal base is eliminated, and a linear portion for fixing the metal base is provided inside.

Specifically, as shown in FIG. 7, the side surface of the metal base 10b of the metal stem 10 was cut off linearly to form an alignment surface 10c. This alignment surface 10c
In the present embodiment, as shown in FIG.
Two are formed so as to be in the same order.

By doing so, the outer peripheral edge of the flange portion 10a of the metal stem 10 is formed in a circular shape without any protruding portion, so that the stem size and the sensor size can be reduced. Then, the alignment surface 10c inserts the lead pin 16 into the metal stem 10 and the low melting glass 30
The thermopile element (infrared detection element) 11 composed of a substrate having a plurality of thermocouples having an infrared absorber on the upper surface of the metal stem 10 is fixed by die bonding while aligning the position. It becomes a positioning surface when the process of electrically connecting the electrode of the detection element 1 and the lead pin 16 of the metal stem 10 by wire bonding or the like is automatically performed using a mounting device, and automatic mounting becomes possible.

Although two orthogonal alignment surfaces 10c are provided in the illustrated example, by providing two such alignment surfaces, positioning on the secondary plane can be performed with high accuracy.
One.

When the sensor size can be reduced in this way, when an ear thermometer is formed using this temperature sensor, a structure as shown in FIG. 8 can be obtained.
That is, the temperature sensor 27 is disposed at the tip of the probe 26, and infrared rays emitted from the eardrum 28 can be directly received by the temperature sensor 27 and measured without providing a waveguide. Therefore, high-precision measurement can be performed without infrared radiation from the waveguide, and the cost can be reduced.

[0044]

As described above, in the can and fixing method with window material and the temperature sensor according to the present invention, the brazing material is used, and the metal thin film provided on the periphery of the window material is brazed to the can. The location of the material depends on the region where the metal thin film is formed. Therefore, the brazing material can be positioned at a position according to the design value without protruding like a resin adhesive. Therefore, according to the second aspect of the present invention, since the brazing material does not protrude into the opening area of the window, the effective area of light passing through the window does not decrease. To increase the sensitivity and increase the output when used as a light emitting element.

Further, the positioning of the window material can be easily performed by melting the brazing material, and the brazing between the metal thin film and the can can be easily performed in a normal atmosphere, so that the workability is improved. Moreover, since the alignment is performed, there is no need to make the window material larger than necessary,
The amount of window material used (external dimensions) can be reduced.
Further, in the temperature sensor formed as described in claim 5, since the positioning projection projecting outside the flange as in the related art is not required, the sensor size can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a conventional temperature sensor.

FIG. 2 is a diagram showing a joining process of a can and a filter.

FIG. 3 is a diagram showing a first preferred embodiment of a temperature sensor according to the present invention.

FIG. 4 is a diagram showing an embodiment of a method for fixing an infrared transmitting filter (window material) and a can.

FIG. 5 is a diagram illustrating the effect of the present invention.

FIG. 6 is a diagram in which the temperature sensor according to the first embodiment is applied to an ear thermometer.

FIG. 7 is a view showing a second preferred embodiment of the temperature sensor according to the present invention.

FIG. 8 is a diagram in which the temperature sensor according to the second embodiment is applied to an ear thermometer.

[Explanation of symbols]

 Reference Signs List 10 metal stem (stem) 10b metal base (base) 10c positioning surface (positioning plane) 11 infrared detecting element 13 can 13b top surface 13c window hole 19 solder (brazing material) 20 metal thin film

Claims (5)

[Claims] 1. A can with a window material comprising: a cap-shaped can having a window hole on a top surface; and a light-transmittable window material attached to the top surface so as to close the window hole. An endless metal thin film is deposited on the periphery of the window material, and the metal thin film and the top surface are brazed and integrated by a brazing material interposed between the metal thin film and the top surface. Can with wood. 2. The window-equipped can according to claim 1, wherein the size and shape of the inner peripheral edge of the metal thin film are equal to or larger than the size and shape of the inner peripheral edge of the window hole. 3. A fixing method for fixing a light-transmissible window material to the top surface of a cap-shaped can having a window hole on the top surface, wherein a metal thin film is vapor-deposited on the entire periphery of the window material, A washer-type solder is disposed between the metal film and the metal thin film, and the window material is fixed to the can by heating and then cooling the solder and bonding the top surface and the metal thin film. And fixing method. 4. A stem having an infrared detecting element mounted thereon, and the can with the window material according to claim 1 or 2 attached to the stem so as to cover the infrared detecting element, wherein the window material is an infrared ray. A temperature sensor, which is a transmission filter, wherein the infrared ray transmitted through the infrared transmission filter is detected by the infrared detection element. 5. The metal stem has a thick base serving as a mounting surface of the infrared transmission filter, and a thin flange protruding outward from a peripheral edge of the base, and is positioned on an outer peripheral side surface of the base. 5. The temperature sensor according to claim 4, wherein a flat surface is provided.