JPS60155934A - Infrared ray detector - Google Patents

Abstract

PURPOSE:To enhance the reliability of an infrared ray detector and to attain the enhancement of fabrication yield, by providing a projection to the cap part of a container having an infrared ray pervious window adhered thereto. CONSTITUTION:A projection 9 is provided to the cap 5 of a container receiving an infrared ray detection element 1 so as to correspond to the part having an infrared ray pervious window 4 adhered thereto by an adhesive 6 and air tightness becomes high and the reliability of the infrared ray detector is enhanced. Further, by the projection 9, the flowing-out of the adhesive 6 toward the window 4 at the time of adhesion is reduced to attain an enhancement of the fabrication yield of the infrared ray detector.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an infrared detector used as a non-contact thermometer in fire alarms, intruder alarms, food temperature control in cooking appliances, and the like.

Conventional configuration and its problems A conventional infrared detector will be explained with reference to Fig. 1.
1 is an infrared detection element such as a thermistor, thermomobile, pyroelectric element, or surface acoustic wave element; 2 is a column attached to the base 3 of the container for thermal insulation; 4 is a cap 5 of the container made of epoxy resin, etc. An infrared transparent window made of silicon, germanium, etc. is shown attached via an adhesive layer 6.

Reference numeral 7 denotes a lead wire for connecting the terminal 8 and the element 1.

To explain the operation of the infrared detector having the above configuration, infrared rays transmitted through the infrared transmitting window 4 are absorbed by the infrared detecting element 1, causing a temperature change in the element 1.

The element 1 converts temperature changes into electrical signals such as changes in resistance and generation of thermoelectromotive force, transmits them to the outside, and operates as an infrared detector.

However, in the above configuration, the infrared transmitting window 4 made of silicon, germanium, etc. and the cap 5 of the container are bonded together via an adhesive layer 6 made of epoxy resin or the like. For this reason, the adhesive layer 6 has insufficient airtightness, causing problems such as moisture entering the inside of the container and deteriorating the characteristics of the infrared detection element. Further, the adhesive forming the adhesive layer 6 protrudes onto the infrared transmitting window 4 during the bonding process, reducing the yield.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide an infrared detector with improved reliability and good yield.

Structure of the Invention The present invention provides an infrared detector comprising a container comprising a through hole having a projection on the inside and an infrared transmitting window bonded in contact with the projection, and an element for detecting infrared rays housed in the container. 1. By providing protrusions around the through holes, the thickness of the adhesive layer can always be the same as the amount of protrusions regardless of the bonding conditions, ensuring a constant thickness of the adhesive layer, resulting in reliability. will improve.

Furthermore, since the portion of the adhesive layer exposed to the outside is protected by the protrusion, reliability against moisture intrusion is improved. Further, by providing the projections, the outflow of the adhesive onto the infrared transmitting window is greatly reduced, regardless of the adhesive case, and the yield is improved.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows a sectional view of an infrared detector in a first embodiment of the present invention. In the figure, the components common to the conventional example are the same as in FIG. Reference numeral 9 indicates a protrusion provided around the through hole toward the inside of the container according to the present invention. To-5 type was used as the base 3 and camp 5 of the container. As the infrared transmitting window 4, a silicon wafer (QJ3ffW thickness) was used.

The protrusion is 100μm or more around the 04πm through hole 1
Formed. As the adhesive for the adhesive layer 6, polyimide resin was used as a result of examining various materials.

If the diameter of each protrusion is less than 100 μm, a sufficient amount of adhesive cannot be secured, so when the infrared transmitting window 4 and the container cap 5 are pressure-bonded in the bonding process, air bubbles may be mixed into the adhesive layer. Secondly, the bonding strength with the infrared transmitting window 4 was insufficient, making it difficult to obtain a practically sufficient adhesive strength. A surface acoustic wave element was used as the element 1 for detecting infrared rays.

A boiling test was conducted to evaluate the reliability of the airtightness of the infrared detector having the above configuration. The results are shown in Table 1. Note that the conventional example had the configuration shown in FIG. 1 and used epoxy resin.

Table 1 Results of boiling test Table 1 shows that when 10 sump/I/s of the conventional example were subjected to a boiling test, two failed after 4 hours, and all failed after 8 hours. In the example of the present invention, all 10 samples were normal after 12 hours of boiling, and 2
This shows that more than half of the 6 samples were normal even after 4 hours. The determination of normality and failure here was determined by measuring insertion loss, which is one of the characteristics of the surface acoustic wave element.

As described above, in the examples based on the present invention, all samples were able to withstand the severe boiling test for more than 12 hours, indicating that reliability was significantly improved compared to conventional ones. There is.

Next, a second embodiment of the present invention is shown in FIG.

In the figure, common components with the first embodiment include the second embodiment.
It is the same as the picture. 6 indicates an adhesive layer of polyimide resin, and 10 indicates an adhesive layer of epoxy resin. in this case,
The airtightness, that is, the results of the boiling test, were the same as in the first example, and it was confirmed that the reliability was improved compared to the conventional one.

Furthermore, in the second example, the adhesive strength of the infrared transmitting window 4 to the cap 5 of the container was significantly improved, and the adhesive strength was 1.2 times longer than that of the first example. Furthermore, by using a conductive epoxy resin as the epoxy resin in the second embodiment, the element 1 that detects infrared rays can be effectively electromagnetically shielded without impairing the adhesive strength.

That is, this is because the cap 5 of the container and the silicon of the infrared transmitting window 4 are electrically connected by adhering them with a conductive epoxy resin. In this case, the element for detecting infrared rays is an external electrical element.

It is effective for pyroelectric elements with high impedance, thermoelectric elements, or thermistor bolometer elements that are susceptible to noise. It is also effective for surface acoustic wave elements that operate at high frequencies.

Furthermore, when a surface acoustic wave element operating at a high frequency of several tens of MHz or higher is used as a front panel for detecting infrared rays, it is more effective if the resistivity of the infrared transmitting window is 10 Ω·α or less. FIG. 4 shows the effect of the second embodiment. In this case, a 0.3 mm thick silicon wafer with a resistivity of 10 Ω·α or less was used as the infrared transmitting window material. FIG. 4 shows measurement results showing the effects of the second embodiment. FIG. 4 shows the response of an infrared detector using a surface acoustic wave element to an infrared input.

In the figure, (,) indicates the infrared input intensity, and (c) indicates an output example of the infrared detector based on the second embodiment. In this case, the operating frequency of the surface acoustic wave element was 174 MHz. As is clear from the figure, according to the second embodiment, a conductive infrared transmitting window of 10Ω·α or less is used, a conductive epoxy resin is used as part of the adhesive layer with the container, By using a surface acoustic wave element as an element for detecting infrared rays, it was possible to reduce the noise level of the infrared detector to 1/j or less without impairing the effects of the first embodiment. The reason for this is that electromagnetic coupling between the surfaces of the surface acoustic wave elements is suppressed because a conductive plate with low resistance at ground potential is provided near the surface of the surface acoustic wave element as an element for detecting infrared rays. This seems to be because the operation of the seiko is more stable. Of course, the electromagnetic shielding effect against external electrical noise is not impaired.

Effects of the Invention 1 According to the infrared detector of the present invention, the reliability regarding airtightness is improved by providing a protrusion in the part where the infrared transmitting window of the container housing the element is bonded, and the reliability of airtightness is improved. The outflow onto the infrared transmission window is reduced, which has the effect of improving yield.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional infrared detector, FIGS. 2 and 3 are sectional views of infrared detectors in the first and second embodiments of the present invention, and FIG. 4 is a sectional view of the infrared detector in the second embodiment. It is a characteristic diagram for showing the effect. 1. Element that detects infrared rays, 3. Base of container, 4.
Infrared transmitting window, 5... Container cap, 6... Adhesive layer,
9...Protrusion of the cap. Name of agent: Patent attorney Toshio Nakao (1 person WA)
I figure 8 Straw 2 rm 4th factor 0 102θo sev Time (S payment) 1

Claims (1)

[Claims] (1) An infrared detector consisting of a container comprising a through hole having a protrusion on the inside and an infrared transmitting window bonded in contact with the protrusion, and an element for detecting infrared rays housed in the container. ■ Claim 1, in which the protrusion is 100 mμ or more, and the infrared transmitting window and the container are bonded with polyimide resin.
Infrared detector described in section. 0) The infrared detector according to claim 2, wherein the infrared transmitting window is made of a conductive material, and the polyimide resin is a polyimide resin and a conductive epoxy resin. 4) The infrared detector according to claim 3, wherein the resistivity of the material of the infrared transmitting window is 10Ω·α or less, and the element for detecting infrared rays is a surface acoustic wave element.