JPH09318451A - Infrared detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an infrared detector in which the electromagnetic shielding effect of a metal case is made sure by a method wherein a protrusion is formed near a window at the metal case so as to pierce an optical filter, the tip part of the protrusion is coupled to the window at the metal case in a state that it is pierced through the part of an insulating film at the optical filter and, the optical filter is fixed and bonded to the window at the metal case by using a jointing material. SOLUTION: A window 21 and burrs 22, 23 are formed at the upper part of a cap 2 by a press working operation, and an optical filter 4 is installed. A base 1 and the cap 2 are airtightly sealed by a welding operation or the like. The optical filter 4 is pierced through the burrs 22, 23 as protrusions at the cap 2 so as to be mounted, and the circumference of the optical filter 4 is coated with a jointing material 14 so as to be hardened and bonded. Thereby, tip parts of the burrs 22, 23 are pierced through insulating films 42 at the optical filter 4 so as to come into contact with a semiconductor substrate 41, and the cap 2 and the optical filter 4 are electrically connected surely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detector, particularly a pyroelectric element, which is used for non-contact temperature detection and human body detection.

[0002]

2. Description of the Related Art The structure of a conventional pyroelectric infrared detector will be described with reference to the drawings. As shown in FIG. 2, the plurality of lead terminals 31 and 32 are hermetically sealed and insulated from the through holes of the base 1 via glass (the ground terminal is not shown). An insulating substrate 5 having a printed wiring is installed on the upper part of the base 1, and FETs 6 are provided on the front and back surfaces thereof.
Supports 8 composed of circuit parts such as resistors 7 and metal columns,
8 is mounted. Then, the light receiving electrodes 10A, 10A
B, back electrodes 12A, 12B, light receiving electrodes 10A, 1
The pyroelectric element 9, which is a ceramic substrate having a pyroelectric property, on which the OB connecting electrode 11 is formed, is fixed on the support body by a conductive bonding material at both ends of the pyroelectric element. The metallic cap 2 for sealing the above-described components has a window 21 on its upper part and an optical filter 4 for transmitting infrared rays. The optical filter 4 has a semiconductor substrate 41 made of, for example, silicon or the like, and an insulating film 42 for transmitting infrared rays having a desired wavelength formed on both main surfaces of the semiconductor substrate 41. Electromagnetic noise generated from other electronic components on the circuit board is also absorbed by these optical filters 4, so that the exposed portion of the semiconductor substrate 41 at the cut surface of the optical filter 4 and the cap 2 as a countermeasure against these electromagnetic noises. Conductive bonding material 1
After making the electrical connection with No. 3, the bonding material 14
Then, it is attached mechanically to the window 21 of the cap 2. Then, the cap 2 is placed on the base 1 to hermetically seal it.

[0003]

However, in the conduction between the exposed portion of the cut surface of the optical filter 4 and the cap by the conductive bonding material, the conductivity varies depending on the coating state of the bonding material and the conductive bonding material. It was easy to occur, and there were cases where perfect continuity (earth) could not be secured. For these reasons, electromagnetic noise cannot be completely grounded and is detected by the element, causing malfunction. Further, the application of the conductive bonding material is a necessary condition, and the cost of the conductive bonding material itself, the process of applying the conductive bonding material, and the like also need to be considered.

An object of the present invention is to provide an inexpensive and highly reliable infrared detector capable of ensuring the electromagnetic shielding effect of the case and simplifying the manufacturing.

[0005]

Therefore, an infrared detector according to the present invention includes an element for detecting infrared rays and the element,
And an infrared detector comprising a metal case having a window for transmitting infrared rays, and an optical filter made of a semiconductor substrate, at least both main surfaces of which are provided with an insulating film for transmitting infrared rays of a desired wavelength, wherein A protrusion is provided in the vicinity of the window of the case, the optical filter is pierced into the protrusion, and the tip of the protrusion is locked in the window of the metal case while penetrating the insulating film portion of the optical filter, and the optical filter is It is fixed to the window of the metal case with a bonding material.

Therefore, the projection of the metal case penetrates the insulating film of the optical filter and comes into contact with the semiconductor substrate portion, further improving the electromagnetic shielding effect of the case. And after locking the optical filter to the protrusion of the metal case,
Since it is completely attached with the bonding material, the mounting accuracy is improved, and the cost of the conductive bonding material itself, the step of applying the conductive bonding material, etc. can be omitted without applying the conductive bonding material that was required in the past. can do.

The projections are burrs formed when the window of the metal case is punched out.

Therefore, when the window of the metal case is provided by press working, it is possible to effectively utilize the unnecessary burr, so that the projection can be obtained more easily and surely. Then, stab the burr with the optical filter,
By attaching to the window of the metal case with the tip of the burr penetrating the insulating film part of the optical filter, the burr penetrates the insulating film of the optical filter and contacts the semiconductor substrate part, and the electromagnetic shielding effect of the case To further improve. Then, after the optical filter is temporarily fixed to the burr, it can be completely attached with a bonding material, so that the mounting accuracy is improved, and the conductive bonding material itself, which is conventionally necessary, is not applied. The cost and the step of applying the conductive bonding material can be omitted.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective front view showing an embodiment of the present invention. The same parts as in the prior art are given the same numbers.

The pyroelectric element 9 is made of lead titanate-based pyroelectric ceramic, is polarized in the plate thickness direction, and is cut into a rectangular shape. The pyroelectric element 9 is generally called a two-element type and has the following electrode structure. That is, on the surface, metal film electrodes (Cr or Ni-) for light reception are formed at a predetermined interval by means such as vapor deposition.
Cr, etc.) 10A, 10B, and metal film electrodes (Ag, etc.) 12A, 12B are provided on the back surface. The light-receiving electrodes 10A and 10B are commonly connected by a connecting electrode (Cr or Ni—Cr) 11.

The base 1 is made of metal, and the base 1 has a plurality of lead terminals 31 and 32 that are electrically independent of each other. The base 1 is hermetically and electrically sealed through the through hole of the base 1 through glass. (The ground terminal is not shown).
Then, the printed wiring insulating substrate 5 is installed on the lead terminals, and an external circuit is formed on the front and back surfaces thereof.
An electronic component 7 such as an ET 6 and a resistor, and supports 8 and 8 are mounted, and the pyroelectric element 9 is mounted on the supports 8 and 8 by a conductive bonding material.

The cap 2 has a window 21 and a burr 2 on its upper portion.
2, 23 are provided by press working, and the optical filter 4 described later is installed.

The optical filter 4 comprises a semiconductor substrate 41 made of, for example, silicon, germanium or the like, and an insulating film 42 for transmitting only infrared rays in a specific wavelength region formed on both main surfaces thereof. This is because the sensitivity of the pyroelectric element 9 does not depend on wavelength, and it is necessary to select a desired wavelength region in advance.

The base 1 and the cap 2 configured as described above are hermetically sealed by a technique such as resistance welding.

Electromagnetic noise generated from other electronic components on the circuit board is also absorbed by these optical filters 4, so it is necessary to take measures against these electromagnetic noises. That is, the optical filter 4 is pierced and attached to the burrs 22 and 23 as the protrusions of the cap 2, and the bonding material 14 (for example, a polyimide-based or epoxy-based resin) is applied to the periphery of the optical filter and cured to bond them. By doing so, the tips of the burrs 22 and 23 penetrate the insulating film 42 of the optical filter 4 and come into contact with the semiconductor substrate 41, so that the cap 2 and the optical filter 4 are electrically connected reliably.

In the embodiment of the present invention, only the burr is shown as the protrusion, but the present invention is not limited to this. For example, a nail-shaped protrusion may be separately provided without any problem.

[0017]

According to the first aspect of the present invention, the projection of the metal case penetrates through the insulating film of the optical filter and comes into contact with the semiconductor substrate portion, thereby further improving the electromagnetic shielding effect of the case. Then, after the optical filter is locked to the protrusion of the metal case, it is completely attached with the bonding material, so that the mounting accuracy is improved, and the conductive bonding material which has been conventionally required is not applied. The cost of itself, the step of applying the conductive bonding material, etc. can be omitted. Therefore, it is possible to provide an inexpensive and highly reliable infrared detector capable of ensuring the electromagnetic shielding effect of the case and simplifying the manufacturing and improving the efficiency.

According to the second aspect of the present invention, when the window of the metal case is provided by press working, it is possible to effectively utilize the unnecessary burrs, so that the projection can be obtained more easily and surely. Then, the optical filter is pierced into the burr, and the burr penetrates the insulating film of the optical filter by attaching the optical filter to the window of the metal case with the tip of the burr penetrating the insulating film portion of the optical filter. It comes in contact with the substrate, further improving the electromagnetic shielding effect of the case. Then, after the optical filter is locked to the burr, it can be completely attached with the bonding material, so that the mounting accuracy is improved, and the conductive bonding material itself, which is conventionally required, is not applied. cost,
The step of applying the conductive bonding material can be omitted. Therefore, ensure the electromagnetic shielding effect of the case,
Moreover, it is possible to provide an inexpensive and highly reliable infrared detector capable of further simplifying manufacturing and improving efficiency.

[Brief description of drawings]

FIG. 1 is a perspective front view showing an embodiment of the present invention.

FIG. 2 is a perspective front view showing a conventional example.

[Explanation of symbols]

 1 ... Base 2 ... Cap 31, 32 ... Lead terminal 4 ... Optical filter 5 ... Insulating substrate 6 ... FET 7 ... Resistor 8 ... Support 9 ... Pyroelectric element

Claims (2)

[Claims] 1. An insulation for detecting an infrared ray, a metal case containing the element and having a window for allowing the infrared ray to pass therethrough, and a semiconductor substrate, at least both main surfaces of which are transparent for transmitting an infrared ray of a desired wavelength. In an infrared detector comprising an optical filter provided with a film, a protrusion is provided in the vicinity of the window of the metal case, the optical filter is pierced into the protrusion, and the tip of the protrusion forms an insulating film portion of the optical filter. An infrared detector characterized by being locked in a window of a metal case in a state of being penetrated, and the optical filter being fixed to the window of the metal case by a bonding material. 2. The infrared detector according to claim 1, wherein the protrusion is a burr formed when the window of the metal case is stamped and punched.