JPH07159234A - Infrared detector - Google Patents

Abstract

PURPOSE:To provide an infrared detector in which the airtightness can be maintained well for a long term. CONSTITUTION:Multilayer films 6A, 6B are formed on an infrared ray transmitting base material 5 to produce a window member 4 which is then bonded to an opening of a vessel 1 housing an infrared detection element 11 thus constituting an infrared detector. In such infrared detector, a solderable metal layer 18 is formed at the cross-sectional part 5a of the base material 5 in the window member 4 and another solderable metal layer 19 is formed at a part 6b of the multilayer film 6B which does not contributes to the angle of visibility. The window member 4 is joined to the vessel 1 by a solder 21 applied between a predetermined part of the vessel 1 and the metal layers 18, 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detector for detecting infrared rays emitted from a human body or the like.

[0002]

2. Description of the Related Art One of the infrared detectors is, for example, a pyroelectric infrared detector disclosed in Japanese Utility Model Laid-Open No. 2-118842. This will be described with reference to FIGS. 5 and 6.
In FIG. 5, reference numeral 1 denotes a lower open-type tubular container made of a metal such as iron, nickel or kovar, and an opening 3 is formed in the upper surface portion 2 at substantially the center thereof. Reference numeral 4 denotes an infrared transmitting window material (hereinafter simply referred to as a window material) provided so as to close the opening 3 from above the container 1. As shown in FIG. 6, a semiconductor such as silicon or germanium is used as a base material 5. A wavelength-selective multilayer film (hereinafter, simply referred to as a multilayer film) 6 is formed on both surfaces of the base material 5, and substantially the entire peripheral side surface and the peripheral portion of the opening 3 are bonded with an insulating resin. Agent 7
Is joined to the container 1 from above the upper surface portion 2.
Reference numeral 8 is a conductive resin adhesive which is additionally provided.

Reference numeral 9 denotes the light-receiving portion electrodes 10 and 11 with respect to the window member 4.
Is an infrared detection element housed in the container 1 so as to face the above, and is made of, for example, PZT (lead zirconate titanate-based oxide ceramics). This infrared detecting element 9
It is provided on a circuit board 13 made of ceramic or the like via a spacer 12. On the lower surface side of the circuit board 13, a FET (field effect transistor) 14 and a high resistance 1
5 is provided, and a plurality of lead pins 16 are provided in a protruding manner. These lead pins 16 extend to the outside of the container 1 through a stem 17 that closes the lower opening of the container 1.

In the pyroelectric infrared detector thus constructed, for example, infrared rays emitted from the human body are used as the window member 4
When it passes through and enters the light receiving portion electrodes 10 and 11 of the infrared detection element 9, a predetermined signal is output from the lead pin 16. In the above-mentioned conventional infrared detector, a semiconductor such as silicon or germanium is used as the base material 5 of the window member 4, and silver is used for joining the window member 4 and the container 1.
Since the conductive resin adhesive 8 in which a metal filler such as copper is dispersed and mixed in the synthetic resin adhesive is used, the window member 4 and the container 1 can be electrically connected, which is convenient.

[0005]

Generally, in a pyroelectric infrared detector, since the impedance of the circuit in the container 1 is extremely large, for example, 10 ¹¹ Ω, changes in the environment such as temperature and humidity. On the other hand, it is necessary to maintain the airtightness inside the container 1. However, as described above, in the conventional pyroelectric infrared detector in which the window material 4 is adhered to the predetermined portion of the container 1 with the resin adhesives 7 and 8, in the test under a harsh environment, It is unavoidable that the outside air or moisture penetrates into the container 1 due to permeation, etc. Therefore, the insulating property in the internal circuit is inevitably lowered, and the reliability is limited.

The environment resistance described above is applicable not only to the pyroelectric infrared detector but also to the thermoelectric infrared detector in which the thermoelectric infrared detector is housed in the container 1 and other infrared detectors. Is also the same.

The present invention has been made in view of the above matters, and an object thereof is to provide an infrared detector capable of maintaining good airtightness for a long period of time.

[0008]

In order to achieve the above object, according to the present invention, a container containing an infrared detecting element is provided with an infrared transmitting window material in which a wavelength selective multilayer film is formed on a base material made of an infrared transmitting material. In the infrared detector joined to the opening formed in, while forming a solderable metal layer in the cross-sectional portion of the base material in the window material,
A solderable metal layer is formed on a portion of the multilayer film that does not contribute to the viewing angle, and the window member is joined to the container by solder applied between a predetermined portion of the container and the metal layers.

[0009]

In the infrared detector having the above structure, the solderable metal layer is formed on the cross section of the base material in the window material for closing the opening formed in the container, and the viewing angle of the multilayer film is improved. A solderable metal layer is formed on a portion that does not contribute, and the window material is joined to the container by solder applied between a predetermined portion of the container and the metal layers. Therefore, the airtightness of the container is improved, and the window member and the container are reliably electrically coupled to each other, so that electromagnetic shielding is excellently performed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In each of the following drawings, the same reference numerals as those shown in FIGS. 7 and 8 indicate the same or equivalent components.

FIGS. 1 and 2 show an example of a pyroelectric infrared detector according to the present invention. The window member 4 shown in these figures has an opening 3 whose upper surface is opened on the upper surface of the container 1. It is provided so as to have the same height (flush) as the upper surface portion 2 surrounding the. Reference numeral 18 denotes a solderable metal layer formed on the cross-section portion 5a sandwiched by the multilayer films 6A and 6B formed on the upper and lower surfaces of the base material 5 of the window material 4, and is formed over the entire circumference of the base material 5. .

Numeral 19 is a solderable metal layer formed in the portion 6b of the multilayer film 6B below the base material 5 which does not contribute to the viewing angle. In this case, the portion 6b that does not contribute to the viewing angle means the light receiving portion electrodes 10 and 11 of the infrared detection element 9.
Is a portion on the outer edge side of the viewing angle defining line 20 connecting the outer edge of the above and the multilayer film 6A on the upper side of the base material 5. Reference numeral 21 denotes a solder portion for joining the window member 4 to the container 1, which is applied to a portion 22 to be joined of the container 1 which has been subjected to a surface treatment in a solderable surface state and the metal layers 18 and 19 of the window member 4. To be done.

Next, an example of a procedure for manufacturing the window member 4 and a procedure for joining the window member 4 to the container 1 will be described.

The base material 5 of the window member 4 is made of a semiconductor such as silicon (Si) or germanium (Ge), and has a diameter of 101.6 mm (4 inches) and a thickness of 0.38 mm.
The wafer state is cut out.

Using a known vapor deposition method, several tens layers of Ge as a high refractive index substance and zinc sulfide (ZnS) as a low refractive index substance are superposed on both surfaces of the wafer. As a result, a multilayer film having wavelength selectivity is formed on the surface of the wafer, and an optical filter is obtained. In this case, it goes without saying that an optical filter having a desired wavelength selectivity can be obtained by appropriately setting the optical film thickness and the number of vapor deposition layers in the multilayer film.

A wafer (optical filter) on which a multilayer film is formed is cut by rotating a rotary blade made of diamond at a high speed to form a pellet of several mm square, that is,
It is formed on the window member 4. This window material 4 cut into small pieces
As shown in FIG. 2, the base material 5 has a multi-layered film 6 on both upper and lower surfaces.
It has a so-called sandwich shape sandwiched between A and 6B.

Then, the exposed cross-section portion 5 of the base material 5
The a and the multilayer films 6A and 6B have no wettability with respect to the solder as they are. Therefore, in this embodiment, the cross-section 5a and the portion 6b of the multilayer film 6B that does not contribute to the viewing angle are subjected to surface treatment by plating or sputtering to form the metal layers 18 and 19.

As the surface treatment by the plating, for example, nickel-phosphorus type, nickel-boron type, and palladium-phosphorus type have strong and stable adhesion strength of the metal layers 18 and 19. Then, in order to further improve the wettability with respect to solder, it is also preferable to finish with gold plating after plating with any of the above.

When the surface treatment is carried out by the above-mentioned sputtering, a metal layer having good wettability to solder is obtained by combining metals such as nickel, chrome, copper and gold as a single layer film or a multilayer film by sputtering. 18 can be obtained.

The material used for the surface treatment by plating or sparring or the combination thereof is not limited to the above-mentioned ones. In short, at least the exposed cross-sectional portion 5a of the base material 5 and the multilayer film 6B.
It suffices that the metal layers 18 and 19 having excellent wettability with respect to solder be formed in the portion 6b that does not contribute to the viewing angle in the above.

On the other hand, the container 1 to which the window member 4 is joined is
It is preferable to form a metal material having good wettability with respect to solder (for example, nickel, Kovar, etc.) by pressing, but a metal material with insufficient wettability against solder (for example, iron) may be used. In both cases, at least the portion 22 to be joined of the window member 4 is
It suffices if the surface treatment is applied to the solderable surface state. Also for this surface treatment, plating or sputtering applied to the surface treatment of the exposed cross-section portion 5a of the base material 5 may be similarly adopted. It should be noted that the surface treatment of the portion 22 to be joined may be performed partially only on the portion corresponding to the solder portion 21, but may be performed on the entire front and back surfaces of the container 1 at once.

The window member 4 formed as described above is provided so as to have the same height (flush) as the upper surface portion 2 surrounding the opening 3 formed on the upper surface of the container 1. The window member 4 is joined to the container 1 by thermally melting, for example, tin-lead based solder in the portion 22 to be joined of the container 1. In that case, the solder portion 21 is formed between the metal layers 18 and 19 formed on the side cross-sectional portion 5a of the window member 4 and the portion 6b of the multilayer film 6B that does not contribute to the viewing angle and the portion 22 to be joined of the container 1. It should be formed. The solder used at this time includes paste-like cream solder, thread-like solder, pellet-like solid solder and the like. Needless to say, other than the tin-lead solder, a solder in which silver is appropriately mixed may be used.

In the infrared detector constructed as described above, the window member 4 and the container 1 are joined together, and moreover, the window member 4
The metal layer 1 having good wettability is formed on the side cross-section portion 5a and the portion 6b that does not contribute to the viewing angle in the multilayer film 6B.
Since 8 and 19 are formed, the window member 4 and the solder portion 2 are formed.
The joining area with 1 is large, so that the window member 4 and the container 1 are joined firmly and reliably as compared with the conventional pyroelectric infrared detector. Therefore, the airtightness of the container 1 is significantly improved, and the base material 5 of the window material 4 is inserted through the solder portion 21.
Since the container 1 and the container 1 are electrically coupled to each other, electromagnetic shielding is excellently performed.

Further, in the above-mentioned embodiment, since the window member 4 is provided so as to be housed in the opening 3 of the container 1, there is an advantage that the original viewing angle of the detector is not damaged.

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways. For example, FIGS. 3 and 4 each show an example in which the window member 4 is provided inside the container 1. In the example shown in FIG. 3, the metal layer 19 formed together with the metal layer 18 has a visual field of the lower multilayer film 6B. Although provided only in the portion 6b that does not contribute to the corner, in the structure shown in FIG. 4, the metal layer 19 is provided in the portions 6a and 6b that do not contribute to the viewing angle of the multilayer films 6A and 6B on the upper and lower sides, respectively.

5 and 6, the window member 4 is attached to the container 1
In the example shown in FIG. 5, the metal layer 19 formed together with the metal layer 18 is provided on the upper side of the multilayer film 6A.
Although it is provided only in the portion 6a that does not contribute to the viewing angle of the above, in the one shown in FIG.
It is provided in the portions 6a and 6b which do not contribute to the viewing angles of A and 6B, respectively.

Needless to say, any of the embodiments shown in FIGS. 3 to 6 has the same effects as those of the embodiments shown in FIGS. Further, in the embodiments shown in FIGS. 3 to 6, a line 20 connecting the outer edges of the light-receiving electrodes 10 and 11 and the upper end of the upper surface 2 facing the opening 3 of the container 1.
Is the viewing angle defining line, and the metal layer 19 is this line 2
It is preferably formed on the outer edge side with respect to 0. By doing so, the viewing angle inherent to the detector is not impaired and the viewing angle can be maximized.

Needless to say, the present invention can be similarly applied to the window member 4 in which the multilayer film is formed only on one surface of the base material 5. Further, it goes without saying that the present invention can also be applied to a thermoelectric stack type infrared detector in which the thermoelectric stack type infrared detecting element is housed in the container 1 and other infrared detectors.

[0029]

As described above, according to the present invention, the joint area between the solder and the window material is large, and therefore,
Compared with the conventional pyroelectric infrared detector, the window member and the container are joined firmly and securely. Therefore, the airtightness of the container is significantly improved, and since the base material of the window material and the container are electrically coupled to each other via the solder portion, the electromagnetic shielding property is improved. Therefore, it is possible to obtain an infrared detector that operates stably over a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a pyroelectric infrared detector according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of the pyroelectric infrared detector shown in FIG.

FIG. 3 is an enlarged sectional view of an essential part showing another mode of mounting the window member.

FIG. 4 is an enlarged sectional view of an essential part showing another mode of mounting the window member.

FIG. 5 is an enlarged sectional view of an essential part showing another mode of mounting the window member.

FIG. 6 is an enlarged sectional view of an essential part showing another mode of mounting the window member.

FIG. 7 is a cross-sectional view showing a conventional pyroelectric infrared detector.

8 is an enlarged cross-sectional view showing a main part of the pyroelectric infrared detector shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Container, 3 ... Opening part, 4 ... Infrared transmitting window material, 5 ... Base material, 5a ... Cross section of base material, 6A, 6B ... Wavelength selective multilayer film, 6a, 6b ... Contribution to viewing angle of multilayer film The part that does not
9 ... Infrared detecting element, 18, 19 ... Metal layer, 21 ... Solder portion.

Claims (1)

[Claims] 1. An infrared detector in which an infrared transmitting window material having a wavelength-selective multilayer film formed on a base material made of an infrared transmitting material is joined to an opening formed in a container accommodating an infrared detecting element, A solderable metal layer is formed on a cross-sectional portion of the base material in the window material, and a solderable metal layer is formed on a portion that does not contribute to the viewing angle of the multilayer film, and a predetermined portion of the container and both the metal layers are formed. An infrared detector characterized in that a window member is joined to a container by solder applied between the two.