JPH0432977B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for efficiently manufacturing a pyroelectric element having an electrode structure that provides stable performance.

[Prior Art] Pyroelectric elements are beginning to be widely used as heat-sensitive elements in infrared sensors and other devices. This pyroelectric element is generally made of a polymer pyroelectric material such as vinylidene fluoride resin or a ceramic pyroelectric material having spontaneous polarization, or a thin layer of pyroelectric material, that is, a polarized film, and electrode films are formed on both sides of the material. It has a formed structure and has the effect of generating a potential difference between the electrodes on both sides due to temperature changes. In general, infrared sensors use such a pyroelectric element as a heat-sensitive element, and generate a voltage on both sides of the pyroelectric element corresponding to the amount of heat generated by the incident infrared rays, which is then amplified appropriately and detected. It has a typical structure.

As an example of such an infrared sensor, the present inventors have already proposed an infrared sensor whose cross-sectional view is shown in FIG. 1 (Utility Application No. 150572/1983).
That is, in this sensor, first, in a metal case (cap) 1 having an infrared transmitting window 1a opened at the top, an infrared transmitting window material 2 made of an ethylene resin film or the like is placed inscribed in the window portion 1a. be done. Further, under this infrared transmitting window material 2, an upper conductor ring 3 and a pyroelectric film 4a (Fig. 2) made of vinyldene fluoride resin, etc. are coated with ITO (indium-tin composite oxide), etc. A transparent front electrode 4b (Fig. 2) and a back electrode 4c (Fig. 2) consisting of
A pyroelectric element 4 having a pyroelectric element 4 and a lower conductor ring 5 are sequentially laminated. Further, in the space below the pyroelectric element 4 and the conductor ring 5, an FET (field effect transistor) 6 as an example of an amplification element is arranged, and a lead wire 6a from the gate thereof is connected to the bottom surface of the lower conductor ring 5. An integral insulating member 7 is inserted into the metal case 1 from the lower part thereof in a press-contact manner. The front edge member 7 includes an upper side engraving 7a surrounding the pyroelectric element 4 and the conductor ring 5, and an upper shelf 7b extending from the upper side wall and supporting the conductor ring 5.
Intermediate side wall 7c surrounding the space accommodating FET6
and a bottom plate 7d, which are integrally molded by injection molding, press molding, etc. of synthetic resin such as ABS. Also, on the bottom plate 7d, the source of FET6,
Drain and ground leads 88a, 8b,
8c is inserted. A shielding metal film (not shown) is formed on the outer surface of the bottom plate 7d by evaporation, plating, etc., and is electrically connected to the ground lead wire 8c, passing through the metal case 1 and the upper conductor ring 3 to the surface of the pyroelectric element 4. Electrode 4 is grounded. Furthermore, the contents of the metal case 1 are
By caulking b, it is made into a closely laminated integral structure.

[Problems to be Solved by the Invention] The infrared sensor shown in FIGS. 1 and 2 described above has a simplified bottom plate and side wall structure including a shield structure, has a small number of parts, and does not require complicated wire bonding or the like. Although it has the feature that it can be manufactured easily and inexpensively without involving any steps, one problem was discovered. This means that the output of actually manufactured infrared sensors varies and is not constant. According to research conducted by the present inventors, it has been found that the main cause of this is the pyroelectric element, particularly its electrode structure.

Therefore, the main object of the present invention is to provide an efficient method for manufacturing a pyroelectric element having stable characteristics.

[Means for Solving the Problem] and [Operation] According to the research conducted by the present inventors, the main cause of the variation in the output of the infrared sensor configured as shown in FIGS. 1 and 2 above has been found. One is to form front and back electrodes 4b,
It has been found that after forming the pyroelectric element 4c, a short circuit occurs between the front and back electrodes 4b and 4c at the stage of punching into the shape of the pyroelectric element 4.

In order to solve this problem, after forming electrodes on both sides of the pyroelectric film, it is sufficient to create an electrode structure in which short circuits between the electrodes on both sides essentially do not occur when punching into an element shape.

Furthermore, in order to incorporate a pyroelectric element into an infrared sensor as shown in FIG. However, in order to simplify this assembly process and make handling of the pyroelectric element easier, at least one of the pair of conductor rings described above should be attached to at least one of the front and back surfaces of the pyroelectric element. It is preferable to adhere it to. Further, such an integrated structure is preferable in terms of stabilizing the characteristics of the pyroelectric element and the infrared sensor, and can be efficiently manufactured from a large-area pyroelectric film as described later.

The present invention provides a method for manufacturing a pyroelectric element having intersecting striped electrodes as described below and a conductive ring attached to at least one surface in electrical continuity with at least one of the electrodes. A plurality of stripe-like electrodes are formed on the front and back surfaces of a large-area pyroelectric film, respectively, so as to be spaced apart and intersect with each other on the front and back surfaces, and on at least one of the front and back surfaces, the stripe-like electrodes are parallel to the plurality of stripe-like electrodes. Applying adhesive in a striped pattern so that the adhesive is arranged alternately, and attaching a plurality of conductive rings with the adhesive so as to surround the intersection points of the striped electrodes on the front and back surfaces to conduct with the striped electrodes, The present invention is characterized in that each of the plurality of conductor rings pasted in this manner is punched out together with the pyroelectric film along its outer periphery.

[Examples] Hereinafter, the present invention will be described in more detail with reference to the drawings. Said FIGS. 1 and 2
Elements with the same reference numerals in the drawings, including figures, are
Indicates that they have similar functions.

FIGS. 3a and 3b are a side sectional view and a plan view, respectively, of a pyroelectric element manufactured by the method of the present invention before the conductor ring is bonded. That is, the pyroelectric element 14 includes ITO on the surface of a pyroelectric film 14a made of vinylidene fluoride resin or the like having spontaneous polarization.
A transparent stripe-like electrode 14b consisting of a transparent stripe-like electrode 14b and a stripe-like electrode 14c are also provided on the back surface, and these stripe-like electrodes 14b and 14c are orthogonal to each other approximately at the center of the pyroelectric film 14a. That is, in the peripheral portion of the pyroelectric element 14, electrodes are not formed on both the front and back surfaces. Therefore, after forming electrodes on the front and back surfaces of the continuous pyroelectric film by vapor deposition, etc., the shape of the element is changed. There is no short circuit between the front and back electrodes when punching.

FIGS. 4a and 4b are a sectional view in the thickness direction and a plan view, respectively, of an example of a pyroelectric element manufactured by the method of the present invention. That is, this pyroelectric element 24 has a pyroelectric film 14a, a striped surface electrode 14, which is substantially the same as the pyroelectric element 14 shown in FIGS.
b. The pyroelectric material is applied to the back surface of the laminate of the striped back electrodes 14c, that is, the back surface of the pyroelectric film 14a, through a pair of striped adhesive layers 20 applied almost parallel to the striped back electrodes 14c. Membrane 1
A lower conductor ring 15 is bonded along the peripheral edge of 4a. As mentioned above, by bonding and integrating at least one of the conductor rings above and below the pyroelectric element with the pyroelectric element in advance, handling of the pyroelectric element becomes easier, and the ring The conductive state between the pyroelectric element and the pyroelectric element is stabilized, and the pyroelectric element characteristics as a whole are also stabilized. As is clear from FIG. 4b, since the ring 15 and the pyroelectric film 14a are bonded to each other at a position different from the electrode 14c, the electrical connection between the ring and the pyroelectric element is established through the adhesive. is not hindered. Although not particularly shown in the drawings, it is easy to understand that the upper conductor ring can also be bonded to form an integrated pyroelectric element structure. In this case, it goes without saying that the adhesive is applied approximately parallel to the striped surface electrodes.

As described above, the present invention provides a method that allows continuous production of pyroelectric elements using a relatively simple method that is less complicated than the conventional production of pyroelectric elements that simply have electrodes on the front and back surfaces. This is what we provide.

That is, as shown in FIG. 5 as a plan view of the outline of the manufacturing process of the pyroelectric element 24 illustrated in FIG. stripe 1
14b and the electrode 14 corresponding to the back electrode 14c
A long pyroelectric film 114a having a large area and having electrode stripes 114c formed on both sides is prepared. Such striped electrodes 114b and 114c
Of these, the longitudinal direction (i.e. the direction of arrow A in the figure)
Regarding the electrode 114c along the width direction, it is possible to completely continuously perform vapor deposition while unwinding the elongated pyroelectric film 114a in the direction of arrow A using a strip mask. This can also be efficiently manufactured by performing vapor deposition while intermittently unwinding the elongated pyroelectric film 114a. This is effectively utilized that the electrodes in the pyroelectric elements illustrated in FIGS. 3 and 4 have a direct stripe shape (however, in the present invention as a whole, the stripe electrodes are completely linear stripes). certain things are not required).

An adhesive 120 such as epoxy or nitrile rubber is applied in a stripe pattern approximately parallel to the electrode 114c extending in the longitudinal direction of the long pyroelectric film 114a formed by the front and back electrode stripes 114b and 114c. After that, a conductor ring 15 is placed in a position surrounding each intersection of the striped electrodes 114b and 114c and covers the adhesive stripes 120 on both sides, and is bonded with an adhesive 120 and is electrically conductive with the electrode 114c. let A sectional view taken along the - line in this state is shown in FIG. Next, by punching this bonded body along the outer diameter of the conductor ring 15, a pyroelectric element as shown in FIGS. 4a and 4b is obtained.

The infrared sensor using the pyroelectric element described above can have essentially the same structure as the infrared sensor shown in FIG. 1. However, instead of the pyroelectric element 4, it can be obtained by using a pyroelectric element according to the method of the present invention, such as a pyroelectric element 24 shown in FIG. If necessary, the upper conductor ring 3 may be inscribed in the top wall of the cap 1 instead of or in addition to the side wall, as shown in Japanese Utility Model Application Publication No. 56-59638. .

[Effects of the Invention] As described above, according to the present invention, an efficient method for manufacturing a pyroelectric element having stable characteristics is provided,
By incorporating this, an infrared sensor that is inexpensive and has stable characteristics is constructed.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the normal cross-sectional structure of an infrared sensor, Fig. 2 is a sectional view in the thickness direction of a conventional pyroelectric element,
3a and b are a cross-sectional view and a plan view, respectively, of a pyroelectric element manufactured by the method of the present invention before the conductor ring is bonded; FIGS. A cross-sectional view and a plan view of the example, FIG. 5 is a plan view showing an outline of the manufacturing process of the pyroelectric element shown in FIG. 4 by the method of the present invention, and FIG. 6 is a cross-sectional view taken along the - line in FIG. . 1...Metal case (1a...Infrared transmitting window, 1
b...lower end caulking part), 2...infrared transmitting window material,
3... Upper conductor ring, 4, 14, 24... Pyroelectric element, 4a, 14a... Pyroelectric film, 4b, 14
b, 114b...Surface electrode, 4c, 14c, 11
4c... Back electrode, 5, 15... Lower conductor ring, 6... FET (6a... Gate lead wire), 7
...Insulating member, 8...Lead wire.

Claims (1)

[Scope of Claims] 1. A plurality of stripe-shaped electrodes are formed on the front and back surfaces of a large-area pyroelectric film, spaced apart from each other and alternately on the front and back surfaces, and the plurality of stripe-shaped electrodes are formed on at least one of the front and back surfaces. Adhesive is applied in stripes so that the electrodes are parallel and intersecting, and a plurality of conductive rings are pasted with the adhesive so as to surround the intersection points of the striped electrodes on the front and back surfaces to form stripes. The method is characterized in that each of the plurality of conductor rings thus pasted is punched out together with the pyroelectric film along its outer periphery.
A method for producing a pyroelectric element having stripe-shaped electrodes that intersect with each other on front and back surfaces, and a conductor ring that is electrically connected to at least one of the electrodes and attached to at least one surface. 2. According to claim 1, the large-area pyroelectric film is a long pyroelectric film, and the striped electrodes provided on one surface of the long pyroelectric film are formed by vapor deposition along the longitudinal direction of the long pyroelectric film. A method of manufacturing the described pyroelectric element.