JP2019128178A - Infrared sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared sensor capable of suppressing a decrease in sensitivity and accuracy due to a temperature change of wiring of a substrate. SOLUTION: A substrate 2, a sensor main body 4 provided on the upper surface of the substrate and having heat-sensitive elements 3A and 3B, and a cylinder installed on the substrate and having an opening above the sensor main body and covering the periphery of the sensor main body The sensor body includes a plurality of lower mounting terminals 4a electrically connected to the thermal element at the lower portion thereof, the substrate is patterned on the upper surface, and the lower mounting terminals are connected thereto. A plurality of upper surface wirings 2a, a plurality of lower surface wirings 2b patterned on the lower surface, and a plurality of via holes 2c penetrating vertically and connecting corresponding upper surface wirings and lower surface wirings. Is provided in the vicinity of the lower mounting terminal. [Selection] Figure 1

Description

  The present invention relates to an infrared sensor that detects infrared rays from a measurement object and measures the temperature of the measurement object.

  Generally, in order to measure the temperature of an object to be measured such as a fixing roller used in an image forming apparatus such as a copying machine or a printer, an infrared sensor is disposed opposite to the object to be measured and receives the radiant heat to measure the temperature. Is installed.

For example, in Patent Documents 1 and 2, a cylindrical light guide having a substrate, a sensor main body which is a heat sensitive part provided on the upper surface of the substrate, and an opening above the sensor main body to cover the periphery of the sensor main body An infrared sensor comprising a member is described.
In these infrared sensors, the wiring formed on the upper surface of the substrate is connected to the mounting terminal of the sensor body.

JP, 2017-181031, A JP 2017-49268 A

The following problems remain in the conventional technology.
In the conventional infrared sensor, since the wiring is on the upper surface of the substrate, the temperature of the wiring on the upper surface of the substrate depending on the use environment due to the influence from the light guide member heated by the infrared light or the temperature change due to the radiant heat of the measurement object Changes that affect the sensor itself, which may reduce the sensitivity and accuracy of the sensor itself.

  The present invention is made in view of the above-mentioned subject, and an object of the present invention is to provide an infrared sensor which can control a fall of sensitivity or accuracy by temperature change of wiring of a substrate.

  The present invention adopts the following configuration in order to solve the problems. That is, the infrared sensor according to the first aspect of the present invention comprises a substrate, a sensor main body provided on the upper surface of the substrate and having a thermosensitive element, and an opening disposed above the sensor main body installed on the substrate. A cylindrical light guide member covering the periphery of the main body, the sensor main body having a plurality of lower mounting terminals electrically connected to the thermosensitive element at the lower portion, and the substrate forming a pattern on the upper surface A plurality of upper surface wiring to which the lower mounting terminal is connected, a plurality of lower surface wiring patterned on the lower surface, and a plurality of upper and lower penetrating wirings and connecting the corresponding upper surface wiring and the lower surface wiring A via hole, and the via hole is provided in the vicinity of the lower mounting terminal.

  In this infrared sensor, the substrate penetrates up and down with a plurality of upper surface wiring patterns formed on the upper surface and the lower mounting terminals of the sensor body connected, and a plurality of lower surface wirings patterned on the lower surface. Because the upper surface wiring and the lower surface wiring are connected by a plurality of via holes, and the via holes are provided in the vicinity of the lower mounting terminals, the upper surface wiring of the substrate can be reduced as much as possible. Can be wired. Therefore, the upper surface wiring is less susceptible to the influence of the heated light guide member and the radiant heat of the measurement object, and these influences can be reduced, and the high sensitivity and accuracy of the sensor body can be obtained. it can. Further, the lower surface side of the substrate has a greater heat dissipation effect than the upper surface side, and the heat of the upper surface side can be dissipated to the lower surface side by the via holes and the lower surface wiring.

An infrared sensor according to a second aspect of the present invention is characterized in that, in the first aspect, the upper surface wiring and the via hole are formed immediately below the sensor main body.
That is, in this infrared sensor, since the upper surface wiring and the via hole are formed immediately below the sensor main body, the upper surface wiring and the via hole are hidden below the sensor main body, so that the influence from the heated light guide member and the measurement object It becomes less susceptible to the radiant heat of objects.

An infrared sensor according to a third aspect of the invention is characterized in that in the second aspect, the plurality of via holes are provided at a central portion of the light guide member in plan view.
That is, in this infrared sensor, since the plurality of via holes are provided at the central portion of the light guide member in plan view, the via holes become far from the light guide member and are less susceptible to the influence from the heated light guide member Become.

An infrared sensor according to a fourth invention is characterized in that, in any one of the first to third inventions, a total area of the plurality of upper surface wirings is smaller than a total area of the plurality of lower surface wirings.
That is, in this infrared sensor, since the total area of the plurality of upper surface wirings is smaller than the total area of the plurality of lower surface wirings, heat dissipation by the upper surface wiring is relatively lowered and heat dissipation by the lower surface wiring is relatively increased.

The present invention has the following effects.
That is, according to the infrared sensor of the present invention, the substrate has a plurality of upper surface wirings to which the lower mounting terminals of the sensor body are connected, a plurality of lower surface wirings, and a plurality of via holes that connect the upper surface wirings and the lower surface wirings. Since the via hole is provided in the vicinity of the lower mounting terminal, the upper surface wiring is less susceptible to the influence from the heated light guide member and the radiant heat of the measurement object.
Therefore, in the infrared sensor of the present invention, the sensor main body is not easily affected by the temperature change of the upper surface wiring, and high sensitivity and accuracy of the sensor main body can be obtained.

It is the top view (a) and bottom view (b) which show 1st Embodiment of the infrared sensor which concerns on this invention. It is an AA line arrow directional cross-sectional view of FIG. In 1st Embodiment, it is a top view (a) and a BB line sectional view (b) showing a sensor main part. In 1st Embodiment, it is a top view which shows a sensor mounting member. In 1st Embodiment, it is a side view which shows a sensor mounting member. FIG. 5 is a back view showing a sensor unit in the first embodiment. It is the top view (a) and bottom view (b) which show 2nd Embodiment of the infrared sensor which concerns on this invention.

  Hereinafter, a first embodiment of an infrared sensor according to the present invention will be described with reference to FIGS. 1 to 6. In each drawing used for the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

As shown in FIGS. 1 and 2, the infrared sensor 1 according to the present embodiment includes a substrate 2, a sensor main body 4 provided on the upper surface of the substrate 2 and the thermosensitive elements 3A and 3B, and a sensor main body installed on the substrate 2. A cylindrical light guide member 5 is provided which has an opening above 4 and covers the periphery of the sensor body 4.
The sensor main body 4 is provided at its lower portion with a plurality of lower mounting terminals 4a electrically connected to the heat sensitive elements 3A and 3B. In the present embodiment, the sensor body 4 is provided with two pairs of lower mounting terminals 4a corresponding to the pair of thermal elements 3A and 3B.

The substrate 2 is a double-sided printed circuit board (PCB), for example, and is formed in a rectangular shape.
The substrate 2 has a plurality of upper surface wirings 2a patterned on the upper surface and connected to the lower mounting terminals 4a, a plurality of lower surface wirings 2b patterned on the lower surface, and corresponding upper surface wirings penetrating vertically. It has a plurality of via holes 2c connecting 2a and lower surface wiring 2b. In this embodiment, the substrate 2 is provided with two pairs of upper surface wirings 2a, two pairs of lower surface wirings 2b, and two pairs of via holes 2c corresponding to the two pairs of lower mounting terminals 4a.

The upper surface wiring 2a and the lower surface wiring 2b are pattern-formed by copper foil or the like.
The total area of the plurality of upper surface wirings 2a is set smaller than the total area of the plurality of lower surface wirings 2b.
The via hole 2c is provided in the vicinity of the lower mounting terminal 4a.
That is, the via hole 2 c is disposed in the vicinity of the lower mounting terminal 4 a and in the vicinity of the outer side of the light guide member 5.
These via holes 2c are formed, for example, by filling the through holes with Cu paste.

Further, the substrate 2 has a plurality of attachment holes 2 d for the light guide member 5. In the present embodiment, a pair of attachment holes 2 d are formed in the substrate 2.
The light guide member 5 has at its lower portion a plurality of fixing claws 5a fitted in the attachment holes 2d in a penetrating state.
The light guide member 5 has a rectangular tube shape, and is formed of, for example, a resin or a metal plate.

Further, the substrate 2 is a plurality of electrode pad portions 2e formed on the upper and lower surfaces of one end portion, and via holes that penetrate through the electrode pad portions 2e in the vertical direction and connect the upper and lower electrode pad portions 2e. It has upper and lower connection parts 2f.
The corresponding lower surface wiring 2b is connected to the electrode pad portion 2e formed on the lower surface. Each lower surface wiring 2b is partially bent and extended so that the entire length becomes the same length.

The sensor main body 4 includes a sensor mounting member 112 and a sensor unit 113 installed on the sensor mounting member 112, as shown in FIG.
As shown in FIGS. 3 and 6, the sensor unit 113 is formed on the insulating substrate 102, a pair of heat sensing elements 3A and 3B provided on the insulating substrate 102, and the heat sensing elements 3A and 3B formed on the insulating substrate 102. It has two pairs of upper pattern wires 121A and 121B connected to 3B.

The insulating substrate 102 has two pairs of terminal electrodes 104 formed at the ends of the two pairs of upper pattern wirings 121A and 121B.
The sensor mounting member 112 includes an insulating mounting member main body 106 formed of resin such as PPS (polyphenylene sulfide), and two pairs of connections provided on the mounting member main body 106 and connected to the upper pattern wirings 121A and 121B. And a member 107.
A lower portion of the connection member 107 serves as a lower mounting terminal 4a.

The mounting member main body 106 is formed in a square shape or a substantially square shape as shown in FIGS. 3 and 4.
The connection member 107 is provided so as to protrude upward from the mounting member main body 106, and the sensor unit 113 is fixed to the upper end portion of the connection member 107 in a state where a gap is formed between the connecting member 107 and the mounting member main body 106.
The connection member 107 is attached to the mounting member main body 106 and has an upper end connected to the terminal electrode 104 by soldering or the like, and a lower end connected to the upper surface wiring 2a by soldering or the like as the lower mounting terminal 4a.

As shown in FIG. 3, the connection member 107 is formed of a conductive material such as a metal having higher thermal conductivity than the mounting member main body 106, and has a terminal pin portion 107a protruding to the side. .
The mounting member body 106 includes a connecting member hole 106a formed on the side and into which the terminal pin portion 107a is inserted and fixed, and a mounting member hole 106a disposed on the upper side and directly below the thermal elements 3A and 3B. And an element housing hole 108 communicating with 106a.
In other words, the terminal pin portion 107a that protrudes long is fixed by being inserted and fitted into the long hole-shaped connecting member hole portion 106a.

The tip of the terminal pin portion 107 a protrudes into the element storage hole 108.
The element housing hole 108 penetrates the mounting member body 106 vertically so as to accommodate the first thermal element 3A and the second thermal element 3B.
Further, as shown in FIGS. 4 and 5, the mounting member main body 106 has a thin portion 106b which is thinner than the other portions except the element storage hole 108. The thin portion 106 b is a hole provided in a central portion of the mounting member main body 106 in a rectangular shape in a plan view.

  In the present embodiment, the mounting member main body 106 has a thin plate-like block shape formed in a substantially square shape in a plan view, and four connecting members 107 are disposed in the vicinity of four corner portions. Connection members 107 are arranged one by one. That is, two portions for supporting the sensor unit 113 are provided on both sides of the mounting member main body 106 at intervals from each other, and the sensor unit 113 is supported and fixed at four locations.

  The sensor unit 113 is supported with a parallel gap between the mounting member body 106 and the sensor unit 113. That is, as described above, the upper portion of the connection member 107 protrudes from the upper surface of the mounting member main body 106 by a fixed amount, and the sensor portion 113 connected to the upper end by soldering or the like is floated from the mounting member main body 106 Support in the state.

The connection member 107 has a terminal slit portion 107c extending under the terminal pin portion 107a opposite to the protruding direction of the terminal pin portion 107a, and the mounting member body 106 is inserted into the terminal slit portion 107c. It has a portion 106c.
The terminal slit portion 107c is formed by being cut in the lateral direction so that the terminal insertion portion 106c can be inserted.
The connecting member 107 is a plate-like member formed by die cutting, etching, or laser processing from a metal plate.

As shown in FIG. 6, the sensor unit 113 has a pair of heat sensitive elements 3A and 3B provided on one surface (lower surface) of the insulating substrate 102 so as to be separated from each other, and one surface of the insulating substrate 102. The formed upper pattern wiring 121A, 121B and the infrared reflection film 122 provided on the other surface of the insulating substrate 102 so as to face the second heat sensing element 3B are provided.
The pair of first upper pattern wirings 121A is a conductive metal film connected to the thermal element 3A, and the pair of second upper pattern wirings 121B is a conductive metal film connected to the thermal element 3B.

The first upper pattern wiring 121A and the second upper pattern wiring 121B are connected at one end to a pair of bonding electrodes 123 formed on the insulating substrate 102 and at the other end. A terminal electrode 104 formed on the insulating substrate 102 is connected.
The terminal portions of the first thermosensitive element 3A and the second thermosensitive element 3B respectively corresponding to the adhesive electrode 123 are adhered by a conductive adhesive such as solder.

  The insulating substrate 102 is formed of an insulating film such as a polyimide resin sheet, and the infrared reflective film 122, the first upper pattern wiring 121A, and the second upper pattern wiring 121B are formed of copper foil. That is, on both sides of the polyimide substrate, which is the insulating substrate 102, the copper foil electrodes, which are the infrared reflective film 122, the first upper pattern wiring 121A, and the second upper pattern wiring 121B, are patterned. It is manufactured by a flexible substrate.

The infrared reflection film 122 is disposed in a substantially square shape directly above the second heat sensing element 3B.
The infrared reflective film 122 is formed of a material having an infrared reflectance higher than that of the insulating substrate 102, and is formed by applying a gold plating film on a copper foil. In addition to the gold plating film, for example, an aluminum vapor deposition film of a mirror surface or an aluminum foil may be used. The infrared reflection film 122 is formed to cover the second heat sensing element 3B with a size larger than that of the second heat sensing element 3B.
In FIG. 3A, the infrared reflection film 122 is hatched.

  The first thermal element 3A and the second thermal element 3B are chip thermistors in which terminal portions are formed at both ends. The thermistors include NTC type, PTC type, CTR type thermistors, etc. In this embodiment, for example, NTC type thermistors are adopted as the first thermosensitive element 3A and the second thermosensitive element 3B. This thermistor is formed of a thermistor material such as a Mn—Co—Cu-based material or a Mn—Co—Fe-based material. The first thermosensitive element 3A is a thermosensitive element for detection, and the second thermosensitive element 3B under the infrared reflection film 122 is a thermosensitive element for compensation.

  As described above, in the infrared sensor 1 of the present embodiment, the substrate 2 is patterned on the upper surface, the plurality of upper surface wirings 2a to which the lower mounting terminals 4a of the sensor body 4 are connected, and the plurality of lower surfaces patterned on the lower surface Wiring 2b and a plurality of via holes 2c penetrating up and down and connecting corresponding upper surface wiring 2a and lower surface wiring 2b are provided, and via hole 2c is provided in the vicinity of lower mounting terminal 4a. The upper surface wiring 2a of the substrate 2 can be reduced as much as possible, and the wiring can be mainly performed by the lower surface wiring 2b on the lower surface of the substrate 2.

Therefore, the top wiring 2a is less susceptible to the influence of the heated light guide member 5 and the radiation heat of the object to be measured, and these effects can be reduced, and the high sensitivity and accuracy of the sensor main body 4 can be obtained. Can be obtained. Further, the lower surface side of the substrate 2 has a larger heat dissipation effect than the upper surface side, and heat from the upper surface side can be radiated to the lower surface side by the via hole 2c and the lower surface wiring 2b.
Further, since the total area of the plurality of upper surface wirings 2a is smaller than the total area of the plurality of lower surface wirings 2b, the heat dissipation by the upper surface wiring 2a is relatively lowered and the heat dissipation by the lower surface wiring 2b is relatively increased.

  Next, a second embodiment of the infrared sensor according to the present invention will be described below with reference to FIG. Note that, in the following description of the embodiment, the same components described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

The difference between the second embodiment and the first embodiment is that, in the first embodiment, the via hole 2c is disposed outside the light guide member 5, and the top wiring 2a also extends to the outside of the light guide member 5 On the other hand, in the infrared sensor 21 of the second embodiment, as shown in FIG. 7, the upper surface wiring 2 a and the via hole 2 c are formed immediately below the sensor main body 4.
That is, in the second embodiment, the upper surface wiring 2 a and the via hole 2 c are provided inside the light guide member 5 and below the sensor body 4.

In particular, the plurality of via holes 2c are provided to be gathered at the central portion of the light guide member 5 in a plan view.
As described above, in the infrared sensor 21 according to the second embodiment, since the upper surface wiring 2a and the via hole 2c are formed immediately below the sensor main body 4, the heating is performed because the upper surface wiring 2a and the via hole 2c are hidden below the sensor main body 4. It becomes more difficult to be affected by the light guide member 5 and the radiant heat of the measurement object.
Further, since the plurality of via holes 2c are provided at the central portion of the light guide member 5 in a plan view, the via holes 2c are far from the light guide member 5, and are less susceptible to the influence from the heated light guide member 5. Become.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, in each of the above embodiments, a sensor main body having two heat sensing elements is adopted, but a sensor main body having one heat sensing element may be adopted.
Further, although the heat sensitive element of the chip thermistor is adopted, a heat sensitive element formed of a thin film thermistor may be adopted.
As the thermal element, a thin film thermistor or a chip thermistor is used as described above, but a pyroelectric element or the like can be used in addition to the thermistor.
In each of the above embodiments, the sensor main body includes the sensor mounting member and the sensor portion installed on the sensor mounting member. However, the sensor main body may have only the sensor portion. In this case, an insulating substrate of an insulating film is installed directly on the substrate.

  1, 2 1 ... infrared sensor, 2 ... substrate, 2a ... upper surface wiring, 2b ... lower surface wiring, 2c ... via hole, 3A, 3B ... thermal sensor, 4 ... sensor body, 4a ... lower mounting terminal, 5 ... light guide member

Claims (4)

A substrate,
A sensor body provided on the upper surface of the substrate and having a thermal element;
And a cylindrical light guide member disposed on the substrate and having an opening above the sensor body to cover the periphery of the sensor body.
The sensor body includes a plurality of lower mounting terminals electrically connected to the thermal element at a lower part thereof,
A plurality of upper surface wirings in which the substrate is patterned on the upper surface and the lower mounting terminals are connected;
A plurality of bottom surface patterns patterned on the bottom surface;
It has a plurality of via holes penetrating vertically and connecting the corresponding upper surface wiring and the corresponding lower surface wiring,
The infrared sensor, wherein the via hole is provided in the vicinity of the lower mounting terminal. In the infrared sensor according to claim 1,
An infrared sensor, wherein the upper surface wiring and the via hole are formed immediately below the sensor body. In the infrared sensor according to claim 2,
An infrared sensor, wherein a plurality of the via holes are provided at a central portion of the light guide member in plan view. In the infrared sensor according to any one of claims 1 to 3,
An infrared sensor, wherein a total area of the plurality of upper surface wirings is smaller than a total area of the plurality of lower surface wirings.

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