JP2012122908A - Pyroelectric infrared detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-mounted pyroelectric infrared detector which has a flange structure for secondary mounting and can be made lower in its total height from a bottom surface of mounting substrate to the top of the pyroelectric infrared detector.SOLUTION: The pyroelectric infrared detector has the flange structure for secondary mounting and is formed with a pattern 6 for allowing surface-mounting so as to achieve lower height. A pyroelectric infrared sensor element, FET, resistor for coping with high frequency noise, and capacitor are connected with a through hole from the upper layer base on which they are mounted to a lower layer base 8. A pattern comprising a metal film is formed on a surface of the lower layer base for the secondary mounting so as to achieve electrical connection and mechanical fixation.

Description

  The present invention relates to a structure of a pyroelectric infrared detector, and is a surface-mountable package excellent in economic efficiency. Pyroelectric infrared detector with improved package shielding performance, and element storage unit size that can be accommodated in less than 4.7 x 4.7 x 2.2 mmt, and mounting substrate during secondary mounting By having the flange structure of FIG. 7 for enabling the mounting method aiming at reducing the total height including the height of the pyroelectric infrared detector from the bottom surface, mounting efficiency and economic efficiency are improved. The present invention relates to an excellent surface mount pyroelectric infrared detector.

  The conventional surface mount pyroelectric infrared detector is intended to reduce the total height including the pyroelectric infrared detector height from the bottom surface of the mounting substrate proposed in Patent Document 1 in the secondary mounting. There are pyroelectric infrared detectors that can be surface-mounted.

  The surface mount pyroelectric infrared detector disclosed in Patent Document 1 is a surface mount pyroelectric infrared detector comprising a metal can 1 having an optical filter 2 and a ceramic substrate 3 as shown in FIGS. A straight type metal lead 5 such as plated Kovar or the like that can be soldered to a surface mounting output extraction pattern provided on the lowermost layer of the ceramic substrate of the container or the forming type metal lead 9 of FIG. 5 is shown in FIG. It is attached by brazing.

  The straight metal lead 5 or the forming metal lead 9 is brazed with a high melting point brazing material such as a ceramic substrate and silver brazing in the lead frame state as shown in FIG. 5, and the lead frame is cut after brazing. Is formed.

  However, in the case of a structure including a lead frame, it is necessary to braze the metal lead in a separate process after the ceramic substrate is manufactured, and there is a problem that the cost is high. In addition, when assembling the pyroelectric infrared detector, processes such as lead cutting and lead correction are required, which increases the number of steps.

Japanese Patent Application No. 2010-174890

  The present invention solves this problem, has a simplified structure that can be mounted on the surface, has excellent shielding properties, and the package size of the element storage portion is less than 4.7 × 4.7 × 2.2 mmt. It is an object of the present invention to provide a pyroelectric infrared detector excellent in economic efficiency by simplifying the manufacturing process.

  In order to solve these problems, the bottom part of the base part is a flange structure that enables the total height including the pyroelectric infrared detector height to be lowered from the bottom surface of the mounting board during secondary mounting. And has an output output terminal 6 that can be secondarily mounted on the upper surface of the flange portion as shown in FIG.

  The base portion has a metal pattern for mounting an element and a signal processing circuit component on the uppermost surface, and a metal pattern for joining to a metal can equipped with an optical filter. In order to efficiently obtain the output, a cavity capable of providing a space between the element and the base, or a support structure for supporting both ends of the element is provided.

  Moreover, it has the metal pattern and through hole for joining with the metal can which comprised the optical filter in any layer, and the whole surface ground layer connected by the side metallization.

  Furthermore, it has a flange structure on at least one side of the bottom layer of the base part, and an output lead-out terminal is formed on the upper surface of the flange structure so that it can be electrically connected and mechanically fixed to the secondary mounting board by soldering or the like. It has a structure.

  A pyroelectric element that receives infrared rays and generates charges due to changes in the amount of incident infrared rays, and FETs, resistors, and capacitors that convert the charges generated by the pyroelectric elements into voltages are electrically connected by pattern wiring to the base portion. In the structure, the base part has a structure with a height of less than 0.8 mm, and the metal can with the optical filter has a height of less than 1.7 mm, and the base part has the base part and the optical filter. The total height of the combined metal cans is stored to less than 2.2 mm.

  The pyroelectric infrared sensor element uses a ferroelectric surface provided with electrodes. However, the pyroelectric infrared detector of the present invention uses a pyroelectric characteristic element having a high Curie temperature that can withstand a reflow process of about 260 ° C.

  Moreover, it is set as the structure which adhere | attached the optical filter which permeate | transmits infrared rays to the infrared rays light-receiving window part of the said metal can.

  The metal can including the base and the optical filter is joined by welding or brazing and hermetically sealed. By hermetically sealing in this way, a pyroelectric infrared detector package is obtained in which the metal can including the base and the optical filter is electrically joined.

  Since the base is composed only of ceramic, it is not necessary to braze the metal leads in a separate process after the ceramic substrate is manufactured, and the lead cutting process and lead correction are also performed in the pyroelectric infrared detector mounting process. This eliminates the need for such a process and reduces man-hours.

  The pyroelectric infrared detector of the present invention has a secondary mounting flange structure for the purpose of reducing the total height of the mounting substrate and the pyroelectric infrared detector by being configured as described above. However, it is possible to provide a pyroelectric infrared detector with excellent shielding properties and a small package, which is excellent in economic efficiency.

  In addition, since the pyroelectric infrared detector has a structure bonded to the metal can with an optical filter, the height of the metal can and the size of the opening of the metal can serving as the infrared light receiving window are: Since it can be changed to any size without depending on the package size of the base portion, a desired field of view can be easily obtained.

It is a perspective external view which shows the pyroelectric infrared detector which concerns on the conventional patent document 1. It is a perspective external view which shows the pyroelectric infrared detector of another form concerning the conventional patent document 1. It is the board | substrate mounting schematic which shows the pyroelectric infrared detector which concerns on the conventional patent document 1. FIG. It is an external view which shows the pyroelectric infrared detector of the formed lead | read | reed which concerns on the conventional patent document 1. FIG. It is an external view which shows a back surface lead | read | reed part by the pyroelectric infrared detector which concerns on the conventional patent document 1. FIG. It is sectional drawing which shows the pyroelectric infrared detector which concerns on Example 1 of this invention. 1 is a perspective external view showing a pyroelectric infrared detector according to Embodiment 1 of the present invention. It is the board | substrate mounting schematic which shows the pyroelectric infrared detector which concerns on Example 1 of this invention. It is the schematic which shows the solder at the time of the pyroelectric infrared detector board | substrate mounting which concerns on Example 1 of this invention. It is a pyroelectric infrared detector board | substrate mounting schematic of another form which concerns on Example 1 of this invention. It is the schematic which shows the solder at the time of the pyroelectric infrared detector board | substrate mounting of another form which concerns on Example 1 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The pyroelectric infrared detector according to the first embodiment will be described in detail with reference to FIGS. 6, 7, and 8. FIG.

  The base part of this pyroelectric infrared detector consists of three layers: an upper layer substrate, an intermediate layer substrate, and a lower layer substrate. The upper layer substrate and the intermediate layer substrate serve as an element housing portion base portion, and the lower layer substrate is a flange that can be secondary mounted. It is a structural part.

  The upper substrate 3 is a ceramic substrate composed of one or more layers, and has a cavity 15 that can provide a space between the element and the upper substrate necessary for efficiently obtaining the output of the pyroelectric infrared sensor element 14. A FET 11 for converting the electric charge generated by the pyroelectric infrared sensor element 14 into a voltage on a wiring formed of a metal film on the uppermost surface of the upper substrate 3, a resistor 12, a resistor 10 for removing external noise, and The capacitor 13 is component-mounted with solder or the like and is electrically connected.

  Further, an insulating protective film may be provided on the metal film wiring on the upper substrate 3 in order to prevent an electrical pattern short circuit when mounting the internal mounted electronic component.

  The pyroelectric infrared sensor element 14 is installed so as to bridge the cavity 16 of the upper substrate 3 and is electrically connected and mechanically fixed by a conductive adhesive or the like.

  The middle layer substrate 7 is a ceramic substrate composed of one or more layers, and has a shield pattern formed of a metal film on the entire surface except through-holes and wirings in order to obtain shielding properties.

  The lower layer substrate 8 is a ceramic substrate composed of one or more layers, and has a structure (hereinafter referred to as a flange structure) that protrudes to two opposite sides of the upper layer substrate and the middle layer substrate as shown in FIG.

  On the upper surface of the flange structure, an output extraction-like pattern 6 electrically connected to the wiring of the upper layer substrate is formed by a wiring pattern such as a through hole.

  Here, the flange structure protrudes in the direction of two opposite sides, but by having at least one side flange structure, the total height including the pyroelectric infrared detector height is lowered from the bottom surface of the mounting board. It becomes a structure that makes things possible.

  By having the flange structure as described above, there is a mounting method aimed at reducing the total height including the pyroelectric infrared detector height from the bottom surface of the mounting board at the time of secondary mounting as shown in FIG. It becomes possible.

  By having a flange structure in this way, electrical connection and mechanical fixing are performed by solder during secondary mounting. As shown in FIG. 9, a fillet made of solder is formed on the side surface of the lower layer substrate 8 to increase the mechanical strength.

  In addition, a shield pattern formed of a metal film is provided on the lower surface 17 of the lower layer substrate 8 in order to obtain a shielding property, and this shield pattern is provided on the entire area where installation is possible.

  Moreover, as another form of Example 1, as shown in FIG. 10, it is also possible to mount a pyroelectric infrared sensor on a substrate. In this case, as shown in FIG. 11, as with the flange structure, a fillet made of solder is formed on the side surface of the lower layer substrate 8 to increase the mechanical strength.

  A metal can 1 plated with a hat-shaped nickel, gold or the like having an opening on the infrared light receiving surface (upper surface) and an optical filter 2 that transmits desired infrared light are pressurized using a heat-resistant adhesive. It is electrically connected depending on the state and is fixed mechanically.

  The upper substrate 3 is electrically connected to and mechanically connected to a hat-shaped metal can 1 having an optical filter 2 that transmits a desired infrared ray at the uppermost surface at the opening of the infrared light receiving surface (upper surface). It has a metal film wiring for this purpose, and is connected to the entire ground layer formed on the intermediate substrate by through holes and side metallization.

  A brazing material is sandwiched between the upper substrate 3 and the flange 4 of the hat-shaped metal can 1 provided with the optical filter 2 that transmits the desired infrared light at the opening of the infrared light receiving surface (upper surface), and the pressure is reduced in a reducing atmosphere. And reflow, and electrically connect by melting the brazing material and mechanically fix.

  The brazing material is a brazing material that exhibits good wettability to the wiring formed by the metal film on the upper substrate 3 and the flange 4 of the metal can 1 and has a melting point that does not melt during reflow in secondary mounting. use.

  As the shape of the brazing material, a sheet-like preform brazing material or a paste-like brazing material is used.

  As another form of the first embodiment, the connection between the upper substrate 3 and the flange 4 of the hat-shaped metal can 1 provided with the optical filter 21 that transmits the desired infrared light at the opening of the infrared light receiving surface (upper surface) is low. Instead of connecting by material, it is also possible to use seam welding.

  When bonding is performed by seam welding, the upper substrate 3 includes an electrical filter 2 that has an optical filter 2 that transmits a desired infrared ray on the uppermost surface thereof and an opening on the infrared light receiving surface (upper surface). It has a metal film wiring with a seal ring plated with nickel, gold, etc. for connection to the entire surface, and is connected to the entire surface ground layer formed on the middle layer substrate by through holes, for output extraction to the lower layer substrate It has a terminal.

  The flange 4 of the hat-type metal can 1 having the above-mentioned upper substrate 3 and the optical filter 2 that transmits a desired infrared ray at the opening of the infrared ray receiving surface (upper surface) is sandwiched between the electrodes, and the current is moved while the electrodes are moved and pressurized. By causing Joule heat to be generated between the seal ring on the upper substrate 3 and the flange 4 of the metal can 1, the plated portion of the flange 4 of the metal can 1 and the plated portion of the seal ring on the upper substrate 3 are caused to flow. The welded portion is welded and electrically connected, and joined by seam welding for mechanical fixation.

  The flange 4 of the metal can 1 is set to 0.5 mm or more, which is a dimension that allows electrodes to pass through in seam welding.

DESCRIPTION OF SYMBOLS 1 Metal can 2 Optical filter 3 Upper layer board | substrate 4 Flange 5 Lead terminal 6 Pattern 7 Middle layer board | substrate 8 Lower layer board | substrate 9 Forming type metal lead 10 Resistance 11 FET
12 Resistor 13 Capacitor 14 Pyroelectric Infrared Sensor Element 15 Pyroelectric Infrared Sensor Element Support 16 Cavity 17 Lower Substrate Back 18 Row 19 Solder Fillet

Claims (2)

  A surface-mount type pyroelectric sensor that is electrically connected and mechanically fixed by a brazing technique between a surface-mount ceramic package substrate mounted with a pyroelectric infrared sensor element, FET, gate resistance, etc., and a metal can equipped with an optical filter. A surface-mounting pyroelectric infrared detector, characterized in that a surface-mounting ceramic substrate has a flange structure for secondary mounting on a surface-mounting infrared detector.   2. The surface-mounted infrared detector according to claim 1, wherein the size of the element housing portion excluding the flange structure portion is less than 4.7 × 4.7 × 2.2 mmt. Electric infrared detector.

Images