JPWO2014010370A1 - Optical sensor and manufacturing method thereof - Google Patents

Abstract

A window (30W) is formed on the bottom surface (30B) facing the opening (30A) of the metal case (30). A step portion (30S) is formed at the peripheral edge of the window portion (30W). The optical filter (28) is loosely fitted into the stepped portion (30S), and a gap (P) having a rectangular planar shape is generated between the stepped portion (30S) and the peripheral portion of the optical filter (28). Adhesive guide grooves (30G1, 30G2) are formed in the bottom surface portion (30B) of the metal case (30). Adhesive induction so that the adhesive guide groove (30G1) is connected to two corners of the gap (P) generated between the step (30S) of the metal case (30) and the peripheral edge of the optical filter (28). A groove (30G1) is formed. By applying an adhesive to the adhesive guide groove (30G1), the adhesive guided in the adhesive guide groove (30G1) is introduced into the gap (P).

Description

  The present invention relates to an optical sensor, and more particularly to an optical sensor in which an optical filter is attached to a metal case and a manufacturing method thereof.

  In general, an optical sensor includes an optical filter that transmits a predetermined wavelength, and an optical element that receives light transmitted through the optical filter. The packaged optical sensor includes, for example, a stem and a metal case (can case) as shown in Patent Document 1, an optical element is attached to the stem, and an optical filter is attached to the metal case. For example, Patent Document 2 shows a structure for attaching an optical filter to a metal case.

  FIG. 5 is a central longitudinal cutaway perspective view of the infrared sensor disclosed in Patent Document 2. FIG. This infrared sensor includes a rectangular plate-shaped optical filter 1 and a metal case 4 in which a rectangular opening window 2 that exposes the outer surface of the optical filter 1 to the outside is formed through a stepped portion 3. Yes. Then, the peripheral edge of the optical filter 1 is bonded and fixed to the inner surface of the step portion 3 with an adhesive. On the inner surface of the metal case 4, a recessed groove portion 10 opened at the inner surface of the step portion 3 is formed. These concave groove portions 10 guide the low-viscosity adhesive 5 applied on the inner surface of the metal case 4 toward the gap S sandwiched between the end surface of the optical filter 1 and the inner surface of the step portion 3.

JP-A-8-128895 JP-A-9-159525

  In the optical sensor having the structure shown in FIG. 5, since the recessed groove portions 10 extend to the four corner portions of the step portion 3, the adhesive 5 is introduced from the corner portion of the step portion 3. Is dropped into one concave groove 10, adhesive is introduced into two adjacent sides of the optical filter 1, and the optical filter 1 may be strongly attracted to the two adjacent sides and the optical filter 1 may tilt. is there.

  The above problem is not limited to an optical sensor having a can package structure. This is a problem that occurs in common with an optical sensor having a package structure in which an optical filter is attached to a metal case.

  An object of the present invention is to provide an optical sensor that suppresses the tilt that occurs when an optical filter is bonded, and a method for manufacturing the same, taking the above problem as a problem to be solved.

(1) The optical sensor according to the present invention includes an opening and a metal case provided with a bottom portion having a window portion facing the opening and having a step portion at a peripheral edge portion, and the step portion of the metal case. An optical filter bonded to the optical filter, and an optical element that receives light transmitted through the optical filter, and is connected to a plurality of locations in a gap formed between the step portion of the metal case and the peripheral portion of the optical filter. An adhesive guide groove is formed on the inner side (inner bottom surface) of the bottom surface of the metal case, and the gap is filled with an adhesive guided by the adhesive guide groove.

  According to the above structure, since the adhesive is guided to a plurality of locations in the gap formed between the step portion of the metal case and the peripheral portion of the optical filter, the adhesive is introduced into two adjacent sides. There is no risk of the optical filter being tilted and the optical filter is not inclined.

(2) It is preferable that the said gap | interval is a rectangle along the periphery of the said window part by planar view, and the both ends of the said adhesive guide groove are connected to the corner part of the said gap | interval. Thus, since the adhesive is introduced from the corner portion of the gap, the adhesive spreads quickly along the rectangular groove, and the optical filter can be more effectively avoided.

(3) The adhesive guide groove includes a first adhesive guide groove connected to adjacent first and second corner portions of the four corner portions of the gap, and adjacent third and fourth corners. It is preferable to include a second adhesive guide groove connected to the portion. With this structure, the adhesive is introduced from the four corners of the gap, so that the optical filter can be more effectively avoided.

(4) It is preferable that the adhesive guide groove has a V-shaped cross section or a U-shaped cross section. If it is this groove shape, there exists an effect that an adhesive agent will spread quickly by capillary action.

(5) An optical sensor manufacturing method according to the present invention includes an opening and a metal case that includes an opening and a bottom surface having a stepped portion that is opposed to the opening and has a stepped portion at the periphery. An optical sensor comprising: an optical filter bonded to the stepped portion; and an optical element that receives light transmitted through the optical filter, wherein the inner side (inner bottom surface) of the metal case has the Form an adhesive guide groove connected to a plurality of locations in the gap formed between the step portion of the metal case and the peripheral portion of the optical filter, and apply (drop) the adhesive to the center portion of the adhesive guide groove The gap is filled with an adhesive guided by the adhesive guide groove.

  According to the above structure, since the adhesive is simultaneously introduced into a plurality of locations in the gap formed between the step portion of the metal case and the peripheral portion of the optical filter, the adhesive is introduced into two adjacent sides. Therefore, there is no possibility that the optical filter is tilted and the optical filter is not tilted.

  According to the present invention, since the adhesive is guided to a plurality of locations in the gap formed between the step portion of the metal case and the peripheral portion of the optical filter, the adhesive is introduced into two adjacent sides. The optical filter is not attracted by, and the tilt of the optical filter can be prevented. Moreover, it can adhere more reliably with an appropriate amount of adhesive.

FIG. 1A is a top view of a pyroelectric infrared sensor according to one embodiment of the present invention, and FIG. 1B is a cross-sectional view of a metal case with an optical filter of the pyroelectric infrared sensor. 2A is a view seen from the opening 30A side of the metal case 30, and FIG. 2B is a view seen from the opening 30A side of the metal case with an optical filter to which the optical filter 28 is bonded. 3A is a cutaway perspective view showing the bottom surface of the metal case 30 and the shape of the optical filter 28, and FIG. 3B is a cutaway perspective view of the metal case with an optical filter. FIG. 4 is an exploded perspective view of the entire pyroelectric infrared sensor. FIG. 5 is a central longitudinal cutaway perspective view of the infrared sensor disclosed in Patent Document 2. FIG.

  FIG. 1A is a top view of a pyroelectric infrared sensor according to one embodiment of the present invention, and FIG. 1B is a cross-sectional view of a metal case with an optical filter of the pyroelectric infrared sensor.

  The metal case 30 is a cylindrical metal case having an opening 30A and a bottom surface facing the opening 30A, and is a so-called round can case. As will be described later, the pyroelectric infrared sensor has a metal case 30 fixed and sealed to a stem on which various elements are arranged.

  2A is a view seen from the opening 30A side of the metal case 30, and FIG. 2B is a view seen from the opening 30A side of the metal case with an optical filter to which the optical filter 28 is bonded. 3A is a cutaway perspective view showing the bottom surface of the metal case 30 and the shape of the optical filter 28, and FIG. 3B is a cutaway perspective view of the metal case with an optical filter.

  A window 30 </ b> W is formed on the bottom surface 30 </ b> B facing the opening 30 </ b> A of the metal case 30. A step portion 30S is formed at the peripheral portion of the window portion 30W. The optical filter 28 is loosely fitted into the step portion 30S. That is, a gap P having a rectangular planar shape (rectangular shape along the periphery of the window 30W in plan view) is formed between the stepped portion 30S and the peripheral portion of the optical filter 28.

  Adhesive guide grooves 30G1 and 30G2 are formed on the bottom surface portion 30B of the metal case 30.

  The adhesive guide grooves 30G1 and 30G2 are formed on the metal case 30 so that the adhesive guide grooves 30G1 and 30G2 are connected to a plurality of locations in the gap P generated between the step portion 30S of the metal case 30 and the peripheral portion of the optical filter 28. It is formed on the bottom surface 30B. In the example shown in FIG. 2B, among the four corner portions of the gap P generated between the step portion 30S of the metal case 30 and the peripheral portion of the optical filter 28, the first corner portion C1 and the second corner portion 2 adjacent to each other. The first adhesive guide groove 30G1 is connected to the corner portion C2. Similarly, of the four corner portions, the second adhesive guiding groove 30G2 is connected to the adjacent third corner portion C3 and fourth corner portion C4.

  The adhesive guide grooves 30G1 and 30G2 have a V-shaped or U-shaped cross section, and the width thereof is, for example, 100 to 300 μm. The gap P is, for example, 50 to 150 μm.

  When the optical filter 28 is bonded to the bottom surface portion 30B of the metal case 30, the optical filter 28 is placed on the step portion 30S, and an adhesive is applied (dropped) to each of the adhesive guide grooves 30G1 and 30G2 with a dispenser. Since both ends of the adhesive guide groove 30G1 are connected to the gap P, and the adhesive guide groove 30G1 and the gap P communicate with each other, the adhesive applied (dropped) to the adhesive guide groove 30G1 is the adhesive guide groove. The adhesive flows into both ends of 30G1, and the adhesive is introduced into the gap P. The same applies to the adhesive guide groove 30G2. In this way, the adhesive guide grooves 30G1 and 30G2 and the gap P are evenly wetted with the adhesive throughout the entire area. Further, the adjacent corner portions C1 and C2 of the gap P communicate with each other through the adhesive guide groove 30G1, and the adjacent corner portions C3 and C4 of the gap P communicate with each other through the adhesive guide groove 30G2, so that the gap P The adhesive thickness tends to be uniform over a wide range. Therefore, the surface tension applied to the optical filter 28 from the step portion 30 </ b> S via the adhesive is equally applied to the entire optical filter 28.

  Thereafter, the optical filter 28 is joined to the step portion 30S by solidifying the adhesive. Therefore, the optical filter 28 is bonded to the step portion 30S around the window portion 30W of the metal case without being inclined.

  The optical filter 28 is, for example, an AR-coated Si plate. The adhesive is, for example, a conductive adhesive and has a viscosity of about 20 to 110 Pa · S. If it is this viscosity range, it will be induced | guided | derived by the adhesive agent induction groove | channels 30G1 and 30G2 by capillary action, and will be introduce | transduced into the clearance gap P.

  According to the structure and the manufacturing method, the adhesive is introduced from the corner portion of the gap formed between the step portion 30S of the metal case 30 and the peripheral portion of the optical filter 28, and the adhesive is applied along the rectangular groove. Since it spreads quickly, the drawing of the optical filter 28 can be avoided, and there is no fear that the optical filter tilts. In particular, by applying (dropping) the adhesive to the central portions of the adhesive guide grooves 30G1 and 30G2, the adhesive is simultaneously introduced into the adjacent corner portions, so that the optical filter 28 can be more effectively avoided. it can.

  In addition, when the cross-sectional shape of the adhesive guide grooves 30G1 and 30G2 is V-shaped or U-shaped, that is, the capillary action acts strongly toward the bottom of the adhesive guide groove, the amount of application (dropping) of the adhesive is reduced. At least the adhesive is guided at the bottom of the adhesive guide grooves 30G1 and 30G2. And when there is much application | coating (dropping) amount of an adhesive agent, the surface layer part of adhesive agent induction groove | channel 30G1, 30G2 is flowed in the state where the depth of the adhesive agent became deep. In either case, the adhesive is guided through the adhesive guide grooves 30G1 and 30G2. Thus, since the cross-sectional shape of the adhesive guide grooves 30G1 and 30G2 is V-shaped or U-shaped, there is an effect that the appropriate amount range of the adhesive to be applied (dropped) is wide.

  FIG. 4 is an exploded perspective view of the entire pyroelectric infrared sensor. The pyroelectric infrared sensor 101 includes a metal stem 12 and a metal case 30. The stem 12 includes a disk-shaped support base (stem base) 12a. In the support base part 12a, three terminal pins 14a to 14c are formed penetrating the support base part 12a in the thickness direction. Among these, the terminal pins 14a and 14b are attached to the support base 12a (hermetically sealed) through the glass material 16, and the terminal pin 14c is directly attached to the support base 12a. In the vicinity of the upper end of each of the terminal pins 14a to 14c, a hook-like member is formed for supporting the alumina substrate 20 by floating from the support base 12a.

  An FET 18 is attached to the lower surface of the alumina substrate 20. A plurality of predetermined electrode patterns 22 are formed on the alumina substrate 20. Each terminal of the FET 18 is electrically connected to each electrode pattern 22 of the alumina substrate 20. In the vicinity of the three corners of the alumina substrate 20, recesses 20a to 20c for fitting the terminal pins 14a to 14c are formed. The terminal pins 14a to 14c are fitted into the recesses 20a to 20c, and are electrically connected to and fixed to the electrode patterns 22 by a conductive paste or the like.

A support base 24 having a substantially concave cross section is fixed to the upper surface of the alumina substrate 20. The support base 24 functions as a high resistance body for supporting the pyroelectric element 26 and obtaining an output voltage. The support table 24 is electrically connected to the corresponding electrode pattern 22 at both ends. The support 24 may be formed of a material such as borosilicate glass or alkali-free glass in that it has low thermal conductivity, mechanical strength, and a resistance value of about 10 ¹¹ Ω. preferable.

  A dual-type pyroelectric element 26 is disposed on the upper surface of the support base 24. As described above, the window 30W is opened in the metal case 30, and the optical filter 28 is bonded to the window 30W. The pyroelectric element 26 is an “optical element” according to the present invention, and receives infrared light transmitted through the optical filter 28.

  The opening of the metal case 30 is resistance-welded to the outer peripheral portion of the support base 12a of the stem 12 so that the inside of the package is sealed.

  In addition, although the cylindrical metal case 30 was shown in embodiment shown above, this invention is not limited to this, For example, it can apply similarly to a rectangular parallelepiped metal case.

  In the embodiment described above, the rectangular optical filter 28 is shown. However, the present invention is not limited to this, and the present invention can be similarly applied to, for example, a disk-shaped optical filter.

  Moreover, the pyroelectric infrared sensor shown in the embodiment is an example, and it goes without saying that the present invention can be applied to various optical sensors in which an optical filter is bonded to a step portion of a metal case.

C1 to C4 Corner portion P Gap 12 Stem 12a Support base portions 14a, 14b, 14c Terminal pin 16 Glass material 18 FET
20 ... Alumina substrate 22 ... Electrode pattern 24 ... Support base 26 ... Pyroelectric element (optical element)
28 ... Optical filter 30 ... Metal case 30A ... Opening 30B ... Bottom surface 101 ... Pyroelectric infrared sensor 30G1 ... First adhesive guide groove 30G2 ... Second adhesive guide groove 30S ... Step part 30W ... Window part

Claims (5)

A metal case comprising an opening, and a bottom surface having a window portion facing the opening and having a stepped portion at a peripheral edge; an optical filter bonded to the stepped portion of the metal case; and the optical In an optical sensor comprising an optical element that receives light passing through a filter,
Adhesive guide grooves that are connected to a plurality of locations in the gap formed between the step portion of the metal case and the peripheral portion of the optical filter are formed inside the bottom surface of the metal case, and the adhesive is formed in the gap. An optical sensor filled with an adhesive guided by a guide groove.   2. The optical sensor according to claim 1, wherein the gap has a rectangular shape along a peripheral edge of the window portion in plan view, and both ends of the adhesive guide groove are connected to corner portions of the gap.   The adhesive guide groove is connected to the first adhesive guide groove connected to the adjacent first and second corner portions and the adjacent third and fourth corner portions among the four corner portions of the gap. The optical sensor according to claim 2, comprising a second adhesive guide groove.   The optical sensor according to claim 1, wherein the adhesive guide groove has a V-shaped cross section or a U-shaped cross section. A metal case comprising an opening, and a bottom surface having a window portion facing the opening and having a stepped portion at a peripheral edge; an optical filter bonded to the stepped portion of the metal case; and the optical An optical element that receives light that passes through a filter, and a method of manufacturing an optical sensor comprising:
Forming an adhesive guide groove connected to a plurality of locations in a gap formed between a step portion of the metal case and a peripheral portion of the optical filter on the inner side of the bottom surface of the metal case; A method of manufacturing an optical sensor, comprising applying an adhesive to a portion and filling the gap with an adhesive guided by the adhesive guide groove.

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