JPH0815007A - Infrared sensor and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an infrared sensor and a measuring method thereof which enables efficient manufacturing with high environmental stability and at a low cost by reducing the generation of noises caused by external electromagnetic waves, disturbed light, heat and the like concerning the infrared sensor which is used for a monitoring device, an infrared image device or the like to detect the existence of a human body. CONSTITUTION:An infrared detector 9 is housed into a recess part 20 comprising an insulating protective body 14 in which sensor circuit parts and a lead frame for connecting the circuit parts electrically and mechanically to be led outside are molded integrally by a resin and a conducting protective body 17 provided in the perimeter of the insulating protective body 14 and an earth terminal 12j extended from the sensor circuit parts is made to conduct directly to at least one point of an end face of an optical filter 18. A conducting inner circumferential heat transfer cover member is arranged in the perimeter of the infrared detector 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared sensor used in a monitoring device for detecting the presence of a human body, an infrared imaging device, etc., and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as microprocessors have become very easy to use, it has been adopted in many devices and apparatuses to perform automatic control by combining them with sensors. As one of such sensors, an infrared sensor is also widely used in the fields of machinery and chemistry, such as measuring instruments, crime prevention and disaster monitoring devices, air conditioners, and lighting equipment. This infrared sensor is roughly classified into two types, a quantum effect type and a thermal effect type. The quantum effect type sensor directly obtains an electric signal by the interaction between light and a substance, and representative examples thereof include those made of Si, Ge, GaAs materials and the like. These have high response speed and high sensitivity due to their detection characteristics, but they are expensive because they require a cooler during driving.

On the other hand, in the heat effect type, after light is absorbed by the element material and converted into heat, an electric signal is generated through a thermoelectric phenomenon (a phenomenon in which the electric resistance of the element changes such as internal resistance and polarization due to temperature rise). A typical example of such a material is a thermopile, a thermistor bolometer, and a pyroelectric element material. Although these are inferior to the quantum effect type sensor in response speed and sensitivity, they have many advantages. For example, the sensitivity is constant over a wide range of wavelengths, and it can be used at room temperature.
It is easy to handle. It is expected that by utilizing these features of the thermal effect type, it is possible to provide an inexpensive and easy-to-use human body detection monitoring device, an infrared imaging device, and a machine control device such as lighting equipment and air conditioning equipment. . Further research and development is progressing from point sensors to line sensors to area sensors. Among these sensors, research on the application of infrared sensors using pyroelectric material is particularly remarkable.

Therefore, a conventional infrared sensor using this pyroelectric element material will be described. For example, FIG. 10 is a side sectional view showing a conventional pyroelectric infrared sensor. As shown in FIG. 10, the field-effect transistor 11, the resistor 10, and the infrared detection element 9 are mounted on the circuit board 3, and the circuit board 3 is attached to the external lead-out terminals 4, 5, 6. Then, the metal case 1 having the hole 8 for receiving infrared rays is sealed 7 on the hametic base 2. The hole 8 of the metal case 1 is provided with an optical filter 18 that selectively transmits infrared rays in a desired wavelength range.

This conventional pyroelectric infrared sensor has a package using a metal hametic seal structure, and since the case is made of metal, an electric shield effect can be obtained, and the structure is strong and excellent. It is characterized by having airtightness.

In addition, as another conventional technique, a technique for making a case using an insulating resin material (Actual No. 55-4219).
No. 6) is also proposed.

[0007]

In the fields of recent human body detection using infrared sensors, monitoring devices related to heat detection, infrared imaging devices, machine control devices, etc., there is a demand for higher performance of the devices. As a matter of course, the infrared sensor is required to have a high response speed with less malfunction due to noise and a higher sensitivity.

However, the conventional technique using the metal hametic seal material (1) has a high packaging cost and can be applied only to expensive special uses. (2) Since the metal case has a large heat capacity, a change in ambient temperature has a large influence on the infrared detection element, resulting in variation in response speed. In other words, the metal case has good thermal conductivity, so that it quickly returns to its original state and cannot follow the sensitivity of the infrared detection element. Further, (3) there is a problem that it is not suitable for mass production and the product becomes expensive.

Further, in the prior art using a case based on an insulating resin material, (1) since the shielding property is poor, the ratio of generation of noises such as electromagnetic waves, disturbance light, heat, etc. increases.
Further, (2) there is a problem that the detection sensitivity becomes unstable with respect to a change in ambient temperature and the characteristics are deteriorated, and (3) there is a problem with respect to reliability that the characteristics are deteriorated by long-term use. was there.

Therefore, the present invention solves these conventional problems. It is resistant to humidity and noise, has little influence on the infrared detecting element even if the ambient temperature changes rapidly, and has a small variation in response speed. It is an object to provide an infrared sensor.

Another object of the present invention is to provide a method for manufacturing an infrared sensor which is excellent in mass productivity and has a high yield.

[0012]

An infrared sensing element, a sensor circuit section for converting a detection signal of the infrared sensing element resin-molded with an insulating protective body into a sensor output, and a conductive material provided around the insulating protective body. A protective body and an optical filter that selectively transmits infrared rays are provided, and a ground terminal extending from the sensor circuit unit is connected to the optical filter.

Further, an infrared detecting element, a sensor circuit portion for converting a detection signal of the infrared detecting element resin-molded with an insulating protective body into a sensor output, a conductive protective body provided around the insulating protective body, and an infrared ray. And an optical filter that selectively transmits the light, and a conductive inner peripheral heat transfer covering member is disposed around the infrared detection element and is connected to the optical filter. Then, it is suitable to provide the conductive inner heat transfer covering member with a shelf for mounting the optical filter.

Further, a sensor circuit, a ground terminal extending from the sensor circuit, and a connection terminal for an infrared detecting element are formed on the lead frame, electronic parts for the sensor circuit portion are mounted on the lead frame, and then unnecessary portions of the lead frame are cut off. It is characterized in that an insulating protective body for an infrared sensor is manufactured by resin-molding the ground terminal and the connection terminal for the infrared detection element in a protruding state.

[0015]

As described above, since the sensor circuit portion is integrally molded with the resin as described above, it is possible to prevent the deterioration of the electronic component due to the adverse effect of moisture or the like. The conductive protective body provided around the insulating protective body acts as a ground to suppress the generation of noise due to external electromagnetic waves. Furthermore, the grounding terminal extended from the sensor circuit section facilitates processing, and the optical filter is connected to this to cause grounding action and heat dissipation, and noise due to external electromagnetic waves, disturbance light, heat, etc. Can be suppressed.

Further, since the conductive inner heat transfer covering member is arranged around the infrared detecting element, heat can be evenly distributed and influence on the infrared detecting element can be transmitted without directivity.
External noise further stabilizes voltage fluctuations. Further, the provision of the shelves stabilizes the placement of the optical filter.

Further, by using the lead frame in which the extended ground terminal and the infrared detecting element connection terminal are formed, it is possible to mass-produce those having stable dimensional accuracy and reduce the cost.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An infrared sensor and a method for manufacturing the same according to the present invention will be described in detail below.

FIG. 1 is a circuit diagram of an infrared sensor according to an embodiment of the present invention. In FIG. 1, 9 is an infrared detecting element, and 10 is a resistor provided in parallel with the infrared detecting element 9. The resistor 10 is provided to stabilize the current.
Reference numeral 11 is a field effect transistor. It has a function of amplifying the detection signal detected by the infrared detecting element 9. A pyroelectric element is suitable as the infrared detection element 9, but a thermopile or a thermistor bolometer may be used.

FIG. 2 is an exploded perspective view showing a state in which electronic parts are mounted on a lead frame when manufacturing an infrared sensor according to an embodiment of the present invention. FIG. 3 is an exploded perspective view of the infrared sensor according to the embodiment of the present invention.

In FIG. 2, reference numeral 12 is a lead frame, which is a connecting portion 12b 'provided over a pair of bases 12a,
12c and extended portions 12d 'and 12e' extended from the pair of bases 12a, respectively. These form a sensor circuit that mounts electronic components on a sensor circuit unit described later. The connecting portion 12b 'and the connecting portion 12c are provided with connecting terminal portions 12f and 12g, respectively, which project in directions opposite to each other. Further, the connecting terminal portions 12f and 12g are bent in the same direction to form connecting portions 12h and 12i, respectively. The connection terminal is extended. Then, for connection with the optical filter 18, a grounding terminal 12j is extended from the connecting portion 12b 'by bending in the same direction as the connecting terminal 12h.

The resistor 10 includes a connecting terminal portion 12g and a connecting portion 12
It is joined to both b'with solder or the like. Further, the field effect transistor 11 has a connection terminal portion 12g and an extension portion 12
Each of d'and 12e 'is joined with solder or the like.

After mounting the field effect transistor 11 and the resistor 10 in this way, unnecessary portions of the lead frame 12 are cut off along the dotted line shown in FIG. That is, both ends of the connecting portion 12b 'are cut, the connecting portion 12c is cut off so that only the central portion thereof is left, and the extending portions 12d', 1
Both ends of 2e 'are cut off. The field effect transistor 11 and the resistor 10 are mounted on the lead frame after the unnecessary portion is cut off in this way, and these constitute a sensor circuit unit for converting the detection signal of the infrared detection element 9 into a sensor output. ing. The sensor circuit portion is covered with a material having weather resistance or the like and resin-molded to form the insulating protective body 14 (see FIG. 3). This work is performed by a transfer molding machine. At this time, the external lead-out terminals 12b, 12e, 12 which are a part of the lead frame 12
d, the pair of extended connection terminals 12h and 12i connected to the infrared detection element 9, and the extended ground terminal 12j are resin-molded in a state of protruding outside the insulating protective body 14. The external lead-out terminal 12b is formed when the base body 12a shown in FIG.
d and 12e are also formed when the base body 12a is cut off.

Of the external lead-out terminals 12d, 12e, 12c, the external lead-out terminal 12e serving as the drain terminal and the external lead-out terminal 12d serving as the source terminal of the field effect transistor 11 are respectively provided with a molding step 16 at their roots. There is. The molding step 16 is a part of the insulating protective body 14,
It is provided for the purpose of preventing the electrically conductive protective body 17 and the external lead-out terminals 12e and 12d, which will be described below, from covering the outside of the insulating protective body 14 from electrically contacting each other.

By the way, it is suitable to use an insulating resin such as acrylonitrile-butadiene-styrene resin, polyethylene terephthalate resin, polycarbonate resin, or epoxy resin as the resin forming the insulating protective body 14. However, it is most preferable to use an epoxy resin. By using the epoxy resin for the insulating protector 14, it is possible to extremely effectively prevent the performance deterioration caused by the dielectric breakdown of the circuit due to the diffusion of water when used in high humidity. Epoxy resin has a molding temperature of 1
It is possible to suppress the temperature to about 70 ° C., and it is possible to prevent the soldered electronic component from falling off. Moreover, since the durability of the resin is high and the coefficient of thermal expansion is close to that of metal, it is possible to prevent airtightness destruction due to temperature fluctuations. Further, it has high heat resistance, and it is possible to form a resin layer on the outside by injection molding.

Next, a conductive protective body 17 is formed around the insulating protective body 14 using an injection molding machine. The conductive protector contains a polycarbonate resin as a main component, contains conductive carbon fibers, and has a specific resistance of 1
It is suitable to use a conductive resin of 0 ^-1 Ωcm. FIG. 4 is an exploded perspective view of the infrared sensor according to the embodiment of the present invention, and FIG. 5 is a side sectional view of the infrared sensor according to the embodiment of the present invention. At this time, if the external lead terminals 12e and 12d are brought into contact with the conductive protector 17, an output cannot be obtained. Therefore, as described above, the molding step 16 is provided and the conductive protector 17 is provided.
Must not come into contact with the external lead-out terminals 12e, 12d.

The conductive protective member 17 is the insulating protective member 1.
4, which covers the periphery of the connection terminal 12h, 12i
Further, the side surface on which the ground terminal 12j is arranged is not formed so as to cover it, but is provided so as to open and surround it. That is, the recess 20 is formed inside the conductive protector 17, and the connection terminals 12h and 12i and the ground terminal 12j are projected inside the recess 20 and are surrounded by the recess 20.

Subsequently, the infrared detecting element 9 is placed in the recess 20, the infrared detecting element 9 is electrically and mechanically connected to the connection terminals 12h and 12i by using a conductive adhesive, and finally the conductive property is obtained. An optical filter 18 made of silicon, which has infrared rays selectively passing therethrough, is attached. As shown in FIG. 5, the grounding terminal 12j connected to the optical filter 18 is connected to the conductive adhesive 1 at the end face portion 18a which is a part of the optical filter 18.
By fixing with 8c, conduction of both can be achieved. The conductive adhesive 18c is made of silver powder and thermosetting resin and has a very stable conductive adhesive property. By thus establishing stable conduction, the optical filter 18 can be electrically grounded. Since it can be directly grounded without the conductive protective body 17, the response speed becomes stable, and external noises such as electromagnetic waves, disturbance light, and heat can be completely prevented. That is, it is possible to realize a noise suppressing effect even though it is of a resin type, without using a metal case having a conventional metal hametic seal structure.

In this embodiment, the ground terminal 12j is provided on only one side, but if both are provided on a plurality of places, the same effect can be surely obtained.

Next, an infrared sensor having a conductive inner heat transfer cover member and a method of manufacturing the same according to another embodiment of the present invention will be described.

FIG. 6 is an exploded perspective view of an infrared sensor according to another embodiment of the present invention. FIG. 7 is a side sectional view of an infrared sensor according to another embodiment of the present invention. FIG. 8 is an exploded perspective view of a conductive inner heat transfer cover member according to another embodiment of the present invention. Figure 9
FIG. 7 is an exploded perspective view of a conductive inner peripheral heat transfer covering member provided with a shelf portion according to another embodiment of the present invention.

In this embodiment, the ground terminal 12j is removed from the molded body of FIG. 4 and a conductive inner heat transfer cover member 21 is provided on the inner peripheral surface of the recess 20.
In another embodiment of the present invention, as described above, the ground terminal 12j
Although the portion is removed, a further excellent effect can be obtained by arranging the ground terminals 12j in parallel. The infrared detection element 9 is electrically and mechanically connected to the connection terminals 12h and 12i with a conductive adhesive 18c. The conductive inner peripheral heat transfer covering member 21 shown in FIGS. 8 and 9 is inserted along the four side surfaces of the recess 20 and electrically and mechanically connected. Next, the end surface 18a of the optical filter 18 made of silicon having conductivity, the inner surface 17a of the conductive protector 17, the bottom surface 18b of the optical filter 18, and the shelf surface 22 of the conductive inner heat transfer covering member 21 are provided. The conductive adhesive 18c and the epoxy-based adhesive are adhered and fixed to each other, and this is used as a window of the light receiving surface of the infrared sensor. Although a thermoelectric pyroelectric element is used as the infrared detecting element 9 in another embodiment of the present invention, other infrared detecting elements such as a thermopile and a thermistor bolometer can be used. The material of the optical filter can be used as long as it is a material that selectively transmits infrared rays such as chalcogen glass or high-density polyethylene, but it is considered that the material with low conductivity may reduce the shielding performance. Optical filter 1
8 is most preferred.

The heat transmitted from the outside often causes the heat to be non-uniformly conducted to the infrared detecting element 9, which causes the base voltage to fluctuate, which causes noise and malfunction. In the past, as a countermeasure against this, the resin was thickened to diffuse the conduction of heat and suppress the fluctuation of the base voltage.However, this impairs the merit that the resin case can reduce the size. . However, in the present invention, by inserting the conductive inner heat transfer covering member 21 into the recess 20, the insulating protective body 14 and the conductive protective body 1 are provided.
The heat conducted through 7 can be diffused uniformly, and the influence on the infrared detecting element 9 can be suppressed to the minimum. Also, noise from the optical filter 18 can be suppressed. Further, a noise suppressing effect can be further obtained by electrically and mechanically connecting the conductive inner heat transfer cover member 21 to the external lead-out terminal 12b.

[0034]

As described above, according to the present invention, the sensor circuit portion for converting the detection signal of the infrared detecting element into the sensor output is integrally molded and connected with resin, so that the electronic parts of Deterioration can be prevented. In addition, the conductive protective body provided around the insulating protective body has an effect of grounding, which can suppress the generation of noise due to external electromagnetic waves. Furthermore, by connecting the ground terminal extended from the sensor circuit section to at least one place on the end face of the optical filter, the effect of grounding and heat dissipation occur, and the generation of noise due to external electromagnetic waves, disturbance light, heat, etc. is suppressed. You can

Further, since the conductive inner heat transfer covering member is arranged around the infrared detecting element, the heat can be uniformly dispersed and the influence on the infrared detecting element can be transmitted without directivity. Generation of noise due to electromagnetic waves is small, and fluctuations in the base voltage and generation of noise due to the influence of ambient light, heat, etc. can be suppressed. Further, by providing the inner heat transfer covering member with the shelves, the mounting of the optical filter becomes stable, mass production is facilitated, and reliability is improved.

Further, by using the lead frame having the connection terminals, it is easy to mass-produce those having stable dimensional accuracy, and it is possible to greatly improve the yield and reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an infrared sensor according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a state in which electronic parts are mounted on a lead frame when manufacturing an infrared sensor according to an embodiment of the present invention.

FIG. 3 is an exploded perspective view of an infrared sensor according to an embodiment of the present invention.

FIG. 4 is an exploded perspective view of an infrared sensor according to an embodiment of the present invention.

FIG. 5 is a side sectional view of an infrared sensor according to an embodiment of the present invention.

FIG. 6 is an exploded perspective view of an infrared sensor according to another embodiment of the present invention.

FIG. 7 is a side sectional view of an infrared sensor according to another embodiment of the present invention.

FIG. 8 is an exploded perspective view of a conductive inner heat transfer cover member according to another embodiment of the present invention.

FIG. 9 is an exploded perspective view of a conductive inner circumferential heat transfer covering member provided with shelves according to another embodiment of the present invention.

FIG. 10 is a side sectional view showing a conventional pyroelectric infrared sensor.

[Explanation of symbols]

 1 Metallic Case 2 Hermetic Base 3 Circuit Board 4, 5, 6 External Lead-out Terminal 7 Seal 8 Hole 9 Infrared Sensing Element 10 Resistor 11 Field Effect Transistor 12 Lead Frame 12a Base 12j Earth Terminal 12h, 12i Connection Terminal 14 Insulation Protection Body 16 Forming Stage 17 Conductive Protective Body 18 Optical Filter 18c Conductive Adhesive 20 Recess 21 Inner Circumferential Heat Transfer Cover Member 22 Shelf

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location G08B 13/191 0803-2E H01L 27/14 35/32 A 37/02 (72) Inventor Koichi Watanabe 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. An infrared sensing element, a sensor circuit section for converting a detection signal of the infrared sensing element resin-molded with an insulating protective body into a sensor output, and a conductive protective body provided around the insulating protective body. And an optical filter that selectively transmits infrared rays, and an earth terminal extending from the sensor circuit section is connected to the optical filter. 2. An infrared sensing element, a sensor circuit section for converting a detection signal of the infrared sensing element resin-molded with an insulating protective body into a sensor output, and a conductive protective body provided around the insulating protective body. And an optical filter that selectively transmits infrared rays, a conductive inner heat transfer covering member is disposed around the infrared detection element, and is connected to the optical filter. Infrared sensor. 3. The infrared sensor according to claim 2, wherein the conductive inner peripheral heat transfer covering member is provided with a shelf for mounting the optical filter. 4. A sensor circuit, a ground terminal extending from the sensor circuit, and an infrared detection element connection terminal are formed on the lead frame, and after the electronic parts for the sensor circuit portion are mounted on the lead frame, the lead frame is not required. A method for manufacturing an infrared sensor, wherein a part is cut off and resin molding is carried out in a state in which the ground terminal and the infrared detecting element connection terminal are projected to manufacture an insulating protective body for an infrared sensor.