KR20230072927A - Multi focus infrared light source and non-dispersive infrared gas sensor using the same - Google Patents

Abstract

According to one embodiment of the present invention, provided is a multifocal infrared light source, comprising: a radiation part that radiates infrared rays; a diffraction part that diffracts the infrared rays radiated by the radiation part and focuses the infrared rays at different distances depending on the wavelength; a reflection part that is coupled between the radiation part and the diffraction part and reflects the infrared rays in one direction toward the diffraction part; and a surface mounting part that is coupled to a lower surface of the radiation part, reflects the infrared rays toward the diffraction part, and forms a soldering pad for surface mounting. The present invention provides a non-dispersive infrared sensor including the multifocal infrared light source. Therefore, the present invention can simplify a structure of the infrared light source and provide a surface-mountable infrared light source with an integrated structure of an infrared light source heating element, a reflector, a surface mounting base substrate, and a multifocal lens.

Description

Multi focus infrared light source and non-dispersive infrared gas sensor using the same}

The present invention relates to a multifocal infrared light source and a non-dispersive infrared gas sensor using the same.

Non-Dispersive Infrared Gas Sensor (NDIR) operates by measuring the amount of infrared rays emitted from an infrared light source and then absorbed by a gas to be detected by an infrared detector. A gas absorbs infrared wavelengths of a certain length according to its molecular structure. The gas concentration can be measured by comparing the amount of infrared rays in a specific wavelength band measured by the infrared detector in the absence of the gas to be detected and the amount of infrared rays in the specific wavelength band measured by the infrared detector in the presence of the gas to be detected. Since non-dispersive infrared gas sensors have higher accuracy than other types of gas sensors, their use is expanding.

KR 10-2246452 B1

An object according to an embodiment of the present invention is to simplify the structure of the infrared light source and provide a surface-mountable infrared light source having a structure in which a heating element for the infrared light source, a reflector, a base substrate for surface mounting, and a multifocal lens are integrated.

An object according to an embodiment of the present invention is to arrange a reflector at a focal length corresponding to an absorption wavelength of a gas to be detected, among various focal lengths of infrared rays emitted from a multifocal infrared light source, and to an optical path reflected through the reflector. It is to provide a non-dispersive infrared gas sensor in which an infrared detector is disposed.

A multifocal infrared light source according to an embodiment of the present invention may include a radiator that emits infrared rays, and a diffraction unit that diffracts infrared rays emitted by the radiator and focuses them at different distances according to wavelengths.

In addition, a reflector coupled between the radiating part and the diffracting part and reflecting the infrared rays in one direction toward the diffracting part, and coupled to the lower surface of the radiating part and reflecting the infrared rays toward the diffracting part, soldering for surface mounting It may further include a surface-mounted part where the pad is formed.

In addition, the surface mounting unit, the radiating unit, the reflecting unit, and the diffracting unit may be sequentially disposed and coupled, and may be sealed to contain an inert gas therein.

In addition, the diffractive portion may be formed by printing a zone plate pattern on a substrate formed of a material having infrared rays transmittance.

In addition, among the above-mentioned multifocal infrared light source, among the infrared focal points emitted from the multifocal infrared light source, a reflector disposed at the focal point of the infrared ray of the absorption wavelength of the target gas, and an infrared detector for detecting the infrared ray reflected from the reflector can include

In addition, in order to measure a plurality of target gases, a plurality of reflectors may be disposed for each focal point of infrared rays of absorption wavelengths of the plurality of target gases.

In addition, a plurality of infrared detectors may be disposed to detect infrared rays reflected by the plurality of reflectors.

In addition, the reflector and the infrared detector may further include a focus movement unit formed to move along the focal point of the infrared rays corresponding to the absorption wavelength of the target gas.

In addition, an infrared absorption layer may be further included so that infrared rays that do not correspond to the absorption wavelength of the target gas do not enter the infrared detector.

In addition, a barrier rib blocking a path from which infrared rays that do not correspond to the absorption wavelength of the target gas enter the infrared detector may be further included.

Features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

Prior to this, the terms or words used in this specification and claims should not be interpreted in a conventional and dictionary sense, and the inventor may appropriately define the concept of the term in order to explain his or her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

According to an embodiment of the present invention, a heating element of an infrared light source, a reflector, a base substrate for surface mounting, and a multifocal lens are integrally configured to provide a surface mountable and simplified optical system.

According to an embodiment of the present invention, among infrared rays of various wavelengths emitted from a multifocal infrared light source, the absorption wavelength of a gas to be detected can be selectively reflected and guided to an infrared detector, so that various types of gas can be detected. .

1 is a cross-sectional view of a multifocal infrared light source according to an embodiment of the present invention.
2 is an exploded cross-sectional view of a multifocal infrared light source according to an embodiment of the present invention.
3 is a plan view of a surface mounting unit according to an embodiment of the present invention.
4 is a plan view of a radiation unit according to an embodiment of the present invention.
5 is a plan view of a reflector according to an embodiment of the present invention.
6 is a diagram illustrating a diffracting unit according to an embodiment of the present invention.
7 is a diagram illustrating a structure for measuring a plurality of target gases of a non-dispersive infrared gas sensor according to an embodiment of the present invention.
8 is a view illustrating a structure for measuring a movable target gas of a non-dispersive infrared gas sensor according to an embodiment of the present invention.

Objects, advantages, and features of one embodiment of the present invention will become more apparent from the following description of one embodiment in conjunction with the accompanying drawings. In adding reference numerals to components of each drawing in this specification, it should be noted that the same components have the same numbers as much as possible, even if they are displayed on different drawings. In addition, terms such as "one side", "other side", "first", and "second" are used to distinguish one component from another, and the components are not limited by the above terms. no. Hereinafter, in describing an embodiment of the present invention, a detailed description of related known technologies that may unnecessarily obscure the subject matter of an embodiment of the present invention will be omitted.

In addition, although terms indicating directions such as up, down, left, right, X-axis, Y-axis, Z-axis, etc. are used in this specification, these terms are only for convenience of explanation, and the observer's viewing position or the placement of the object It should be understood that it may be expressed differently depending on the location in which it is located.

In addition, it should be noted that the terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention, and singular expressions include plural expressions unless otherwise specified in context.

Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail.

1 is a cross-sectional view of a multifocal infrared light source 10 according to an embodiment of the present invention. 2 is an exploded cross-sectional view of a multifocal infrared light source 10 according to an embodiment of the present invention. 3 is a plan view of a radiation unit 120 according to an embodiment of the present invention. 4 is a plan view of the reflector 130 according to an embodiment of the present invention. 5 is a plan view of a surface mounting unit 110 according to an embodiment of the present invention. 6 is a diagram illustrating a diffracting unit 140 according to an embodiment of the present invention. 1 to 6 are also referred to.

As shown in FIGS. 1 and 2 , the multifocal infrared light source 10 according to an embodiment of the present invention includes a radiator 120 that emits infrared rays and diffracts infrared rays emitted by the radiator 120. It may include a diffracting unit 140 that focuses at different distances according to wavelengths. The radiation unit 120 may emit infrared rays having various wavelengths. The diffraction unit 140 diffracts infrared rays of various wavelengths emitted from the radiation unit 120 by using a phenomenon in which the degree of diffraction is small when the wavelength is short and the degree of diffraction is high when the wavelength is long. Infrared rays diffracted by the radiating unit 120 may be focused at various distances and positions from the diffracting unit 140 . The position of the focal point of the infrared rays diffracted by the radiating unit 120 may be closer to the diffracting unit 140 as the wavelength is longer. For example, if the first wavelength (λ ₁ ) is longer than the second wavelength (λ ₂ ), the focus F1 of the infrared rays of the first wavelength (λ ₁ ) is the focus F2 of the infrared rays of the second wavelength (λ ₂ ). ) may be formed closer to the diffractive portion 140 than Accordingly, the multifocal infrared light source 10 may focus infrared rays of various wavelengths at different locations.

The multifocal infrared light source 10 according to one embodiment of the present invention is coupled between the radiating unit 120 and the diffracting unit 140, and the reflecting unit 130 reflects infrared rays in one direction toward the diffracting unit 140. ), and a surface mounting unit 110 coupled to the lower surface of the radiating unit 120, reflecting infrared rays toward the diffracting unit 140, and forming a soldering pad 114 for surface mounting. . The multifocal infrared light source 10 may be integrally formed using an MEMS process. The integrally formed multifocal infrared light source 10 can simplify the optical system structure of the non-dispersive infrared gas sensor 1 . The surface mounting unit 110 of the multifocal infrared light source 10 may be directly connected to a PCB board. The surface mounting unit 110 may be physically and electrically connected to the PCB board by soldering.

The surface mounting unit 110, the radiating unit 120, the reflecting unit 130, and the diffracting unit 140 may be sequentially arranged and combined. The radiation unit 120 and the surface mounting unit 110 may be electrically connected by wire bonding. The multifocal infrared light source 10 may further include a molding part 152 protecting the wire 151 for wire bonding. Hereinafter, the surface mounting unit 110, the radiating unit 120, the reflecting unit 130, and the diffracting unit 140 will be described in detail.

See Figures 2 and 3. The surface mounting unit 110 according to an embodiment of the present invention is formed on the first substrate 111 and the first substrate 111 to reflect infrared rays emitted from the radiating unit 120 in the direction of the diffracting unit 140. The first reflective layer 112, the soldering pad 114 connected to the external circuit, the first wire bonding pad 113 connected to the radiation part 120 by wire bonding, the soldering pad 114 and the first wire bonding pad ( 113) may include a first electrode pattern 115 connecting them. The surface mounting unit 110 may further include a dummy pad 117 for physical connection with an external circuit. The surface mounting unit 110 may further include an alignment groove 116 formed on one surface of the first substrate 111 so that the radiating unit 120 can be disposed in an accurate position.

The first substrate 111 may be formed of a silicon (Si) material to which an MEMS process can be applied. The first substrate 111 may be formed of various materials such as silicon, glass, and PCB, but is preferably formed of a material that can use a semiconductor manufacturing process.

Alignment grooves 116 may be formed on one surface of the first substrate 111 coupled to the radiation portion 120 . The alignment groove 116 may be a groove obtained by removing a portion of one surface of the first substrate 111 . The alignment groove 116 may be formed to correspond to the shape of the radiation portion 120 . The alignment groove 116 may be formed at a position where the radiation part 120 is to be disposed. When the radiation part 120 is coupled to the surface mounting part 110, the radiation part 120 may be coupled in such a way as to be disposed inside the alignment groove 116. Since the step 116a is formed at the edge of the alignment groove 116, the radiation part 120 can be accurately seated in the alignment groove 116.

The first reflective layer 112 may be formed on one surface of the first substrate 111 . The first reflective layer 112 may be formed inside the alignment groove 116 . The first reflective layer 112 may be formed of a material that reflects infrared rays. The first reflective layer 112 is formed to correspond to the shape of the first cavity 122 of the radiating unit 120, and radiates from the radiating unit 120 toward the surface mounting unit 110 through the first cavity 122. It may be formed to reflect infrared rays to be directed toward the diffracting unit 140 .

The soldering pad 114 may be formed on one side of the first substrate 111 . The soldering pads 114 may be formed over portions of one surface 111a, the other surface 111b, and a side surface 111c of the first substrate 111 . Two soldering pads 114 may be formed on the first substrate 111 and spaced apart from each other. The first wire bonding pad 113 may be formed on the electrode pattern 115 . The electrode pattern 115 may connect the soldering pad 114 and the first wire bonding pad 113 . The soldering pad 114, the first wire bonding pad 113, and the electrode pattern 115 are made of a material having electrical conductivity, for example, a metal such as copper (Cu), aluminum (Al), silver (Ag), or the like. It can be formed of an alloy containing

The soldering pad 114 may be coupled to the external circuit by solder while being mounted on an external circuit (eg, a PCB of the non-dispersive infrared gas sensor 1). The dummy pad 117 may be formed over portions of one surface 111a, the other surface 111b, and the side surface 111c of the first substrate 111 . The dummy pad 117 may be coupled to the external circuit by solder while being mounted on the external circuit. A dummy pad may be formed opposite the soldering pad 114 to physically fix the multifocal infrared light source 10 to an external circuit.

See Figures 2 and 4. The radiation part 120 according to an embodiment of the present invention is formed on the second substrate 121 on which the first cavity 122 is formed, the membrane 123 formed on one surface of the second substrate 121, and the membrane 123. It may include a formed heating pattern 124 and a second wire bonding pad 125 connected to the heating pattern 124 and connected to the surface mount unit 110 by wire bonding. The radiation unit 120 may further include an infrared emitting material 126 formed on the heating pattern 124 located in the heating region 123a of the membrane 123 . The radiation part 120 may be coupled to the surface mounting part 110 according to the alignment groove 116 .

Like the first substrate 111 , the second substrate 121 may be formed of silicon (Si). A first cavity 122 may be formed in the center of the second substrate 121 . The first cavity 122 is an empty space formed by removing a part of the second substrate 121 . One surface of the first cavity 122 is blocked by the membrane 123 . A membrane 123 may be formed on one surface 121a of the second substrate 121 . The membrane 123 is formed by laminating an electrical insulating film on one surface 121a of the second substrate 121 or forming a silicon oxide (SiOx) layer by oxidizing the one surface 121a of the second substrate 121. It can be. The first cavity 122 may be formed by etching a portion of the second substrate 121 . The membrane 123 is a very thin layer compared to the second substrate 121 . The membrane 123 may be formed of a material with low thermal conductivity.

The heating pattern 124 may be formed of a material that generates heat by resistance when current flows. The heating pattern 124 may be formed of an alloy containing platinum (Pt), ceramic, or the like. The heating pattern 124 starts from one edge of the second substrate 121 and is formed in a serpentine pattern in the region of the membrane 123 where the lower surface is exposed by the second cavity 132, and is formed in a serpentine pattern on the second substrate 121. It may be formed to continue to the other edge of (121). A second wire bonding pad 125 may be formed at an end of the heating pattern 124 reaching the edge of the second substrate 121 .

The heating region 123a is a portion where the second substrate 121 does not exist on the lower surface of the membrane 123 due to the first cavity 122 . When current flows through the heating pattern 124 , heat is generated throughout the heating pattern 124 . Heat generated from the heating pattern 124 included in the heating area 123a is less emitted to the outside because the thickness of the membrane 123 is thin and the lower surface of the membrane 123 is an empty space. On the other hand, a large amount of heat generated from the heating pattern 124 located outside the heating area 123a is released to the second substrate 121 through the membrane 123 . Accordingly, the temperature of a portion of the heating pattern 124 included in the heating region 123a rises, and infrared rays of various wavelengths may be emitted according to the increased temperature.

The infrared emitting material 126 may be formed on the heating pattern 124 included in the heating region 123a. The infrared emitting material 126 is a material that emits high infrared rays as the temperature rises. The infrared emitting material 126 may include platinum black (Pt Black). The heating pattern 124 made of platinum (Pt) material used for heating does not have a high amount of infrared radiation as the temperature rises. Therefore, when the infrared emitting material 126 is formed on the heating pattern 124, the temperature of the heating pattern 124 rises, thereby increasing the temperature of the infrared emitting material 126 and emitting more infrared rays.

Infrared light can be emitted at different wavelengths depending on the temperature. By controlling the current applied to the multifocal infrared light source 10, the temperature of the heating pattern 124 can be controlled and the wavelength of emitted infrared rays can be controlled.

See Figures 2 and 4. The reflector 130 according to an embodiment of the present invention may include a third substrate 131 having a second cavity 132 formed therein, and a second reflective layer 133 formed on an inner surface of the cavity. The reflector 130 may be coupled to the membrane 123 of the emitter 120 . The reflection part 130 may be coupled to the radiation part 120 so that the second wire bonding pad 125 is exposed.

The third substrate 131 may be formed of silicon (Si) like the first substrate 111 or the second substrate 121 . A second cavity 132 may be formed in the center of the third substrate 131 . The second cavity 132 may be formed to pass through one surface and the other surface of the third substrate 131 . The second cavity 132 may have a narrow bottom surface and a wide top surface. The second cavity 132 may be formed in the shape of a frustum of cone or a frustum of quadrangular pyramid as a whole. A wide surface of the second cavity 132 may be formed to correspond to the diffractive portion 140, and a narrow surface of the second cavity 132 may be formed to correspond to the heating region 123a. The second reflective layer 133 may be formed on an inner surface of the second cavity 132 . The second reflective layer 133 may be formed of a material that reflects infrared rays. Infrared rays emitted from the heating pattern 124 are directed in various directions. The second reflective layer 133 may reflect infrared rays emitted from the heating pattern 124 toward the inner surface of the second cavity 132 toward the diffractive portion 140 .

See Figures 1, 2 and 5. The diffractive portion 140 according to an embodiment of the present invention may be formed by printing a zone plate pattern 142 on a substrate formed of a material that transmits infrared rays. The diffractive part 140 may include a fourth substrate 141 formed of a material through which infrared rays pass, and a zone plate pattern 142 formed on the fourth substrate 141 . The diffractive part 140 may be combined with the reflecting part 130 .

The fourth substrate 141 may be formed of a material that is transparent to infrared rays, such as glass. A zone plate pattern 142 may be formed on one surface of the fourth substrate 141 . The fourth substrate 141 may be coupled to the reflector 130 so that the surface on which the zone plate pattern 142 is formed faces the reflector 130 . The zone plate pattern 142 may be formed of a material that does not pass infrared rays, such as a metal layer. The zone plate pattern 142 may include a blocking region 142a formed of a material that is opaque to infrared rays and a pass region 142b that is transparent to infrared rays. The blocking region 142a may be formed of a metal layer, and the pass region 142b may be a region in which the metal layer is not formed. In the zone plate pattern 142, a plurality of blocking regions 142a in the form of circular rings having the same center may be formed to be spaced apart from each other, and a gap between the blocking regions 142a may become a passing region 142b. The width, shape, spacing, etc. of the blocking region 142a and the passing region 142b of the zone plate pattern 142 may be designed in various ways according to the absorption wavelength of the target gas.

The diffracting unit 140 may diffract infrared rays emitted from the radiator 120 , infrared rays reflected from the reflector 130 , and infrared rays reflected from the first reflection layer 112 of the surface mount unit 110 . Infrared light passing through the diffracting unit 140 is focused at a location closer to the diffracting unit 140 as the wavelength is longer. The zone plate pattern 142 of the diffracting unit 140 may be designed according to the wavelength absorbed by the target gas. For example, it is assumed that three types of target gases are detected. A focal point of infrared rays corresponding to a first absorption wavelength of a first target gas is disposed at a first distance, a focal point of infrared rays corresponding to a second absorption wavelength of a second target gas is disposed at a second distance, and a third target gas The zone plate pattern 142 may be designed so that the focal point of the infrared rays corresponding to the third absorption wavelength of is disposed at the third distance.

The surface mounting unit 110, the radiating unit 120, the reflecting unit 130, and the diffracting unit 140 may be sequentially disposed and coupled, and may be sealed to contain an inert gas therein. An adhesive layer or an adhesive may be disposed between the surface mounting unit 110 , the radiating unit 120 , the reflecting unit 130 , and the diffracting unit 140 to be coupled to each other. The first wire bonding pad 113 and the second wire bonding pad 125 may be connected by a wire 151 . The molding portion 152 may be formed to cover the first wire bonding pad 113 , the wire 151 , and the second wire bonding pad 125 . The molding part 152 may be formed of a material having electrical insulation properties.

When the heating pattern 124 is heated to emit infrared rays, when the heating pattern 124 is exposed to air, it may react with oxygen and be oxidized. The multifocal infrared light source 10 may include an inert gas inside to prevent a chemical reaction between the gas and the heating pattern 124 without oxygen contacting the heating pattern 124 . An inert gas may be filled in the first cavity 122 and the second cavity 132 . The coupling between the surface mounting unit 110 and the radiating unit 120, the coupling between the radiating unit 120 and the reflecting unit 130, and the coupling between the reflecting unit 130 and the diffracting unit 140 are first The inert gas filled in the cavity 122 and the second cavity 132 may be sealed so as not to leak.

Since the light source using a conventional bulb type infrared lamp has low light efficiency, a concave mirror type condensing reflector 20 is required for light condensing, and the lamp and the reflector 20 must be assembled in a separate package, A narrowband infrared filter was needed that only passes the absorption wavelength of the target gas among infrared rays of various wavelengths.

According to one embodiment of the present invention described above, since the multifocal infrared light source 10 is manufactured integrally by applying the MEMS process, it is possible to provide a light source having a small size and a thin thickness. In addition, since the multifocal infrared light source 10 performs all functions of infrared emission, reflection of infrared light, and diffraction of concentrating infrared rays of the same wavelength, the optical structure of the non-dispersive infrared gas sensor 1 is simplified. There is an effect. In addition, since the multifocal infrared light source 10 can be coupled to the circuit board of the non-dispersive infrared gas sensor 1 in a surface-mounted manner, there is an effect of simplifying the coupling structure.

7 is a view illustrating a structure for measuring a plurality of target gases of a non-dispersive infrared gas sensor 1 according to an embodiment of the present invention.

The non-dispersive infrared gas sensor 1 according to an embodiment of the present invention may include the multifocal infrared light source 10 described above. The non-dispersive infrared gas sensor 1 includes a multifocal infrared light source 10 and a reflector 20 disposed at the focal point of the infrared rays of the absorption wavelength of the target gas among the focal points of the infrared rays emitted from the multifocal infrared light source 10. , and an infrared detector 30 for detecting infrared rays reflected from the reflector 20 .

The multifocal infrared light source 10 may diffract infrared rays to form a focus at different positions according to wavelengths. When the reflector 20 is positioned at the focal point of the infrared rays corresponding to the absorption wavelength of the target gas, the reflector 20 may reflect only the infrared rays corresponding to the absorption wavelength of the target gas. Since infrared rays having longer or shorter wavelengths than the absorption wavelength of the target gas are focused at different distances, most of the infrared rays reflected by the reflector 20 may be absorption wavelengths of the target gas.

The reflector 20 may be disposed obliquely by a predetermined angle from the central line of the multifocal infrared light source 10 so that the focused infrared light sources are directed toward the infrared detector 30 . Based on the distance between the multifocal infrared light source 10 and the reflector 20 and the distance between the reflector 20 and the infrared detector 30, the reflector 20 may be a concave mirror or a convex mirror. The reflector 20 may be formed as small as possible to minimize reflection of infrared rays of other wavelengths.

Infrared rays reflected by the reflector 20 may be measured by the infrared detector 30 . The infrared detector 30 may measure the intensity of infrared rays and output them as electrical signals. Gas including the target gas may flow between the reflector 20 and the infrared detector 30 . Since the infrared rays reflected by the reflector 20 correspond to the absorption wavelength of the target gas, the output value of the infrared detector 30 decreases as the amount of the target gas increases.

A non-dispersive infrared gas sensor 1 according to an embodiment of the present invention may include a plurality of reflectors 20 and a plurality of infrared detectors 30 . In order to measure a plurality of target gases, a plurality of reflectors 20 may be disposed for each focal point of infrared rays of absorption wavelengths of a plurality of target gases. In addition, a plurality of infrared detectors 30 may be disposed to detect infrared rays reflected by the plurality of reflectors 20 .

As shown in FIG. 7, a structure having three reflectors 20 and three infrared detectors 30 will be described as a reference. Alternatively, it should be understood that a structure having a different number of reflectors 20 and infrared detectors 30 may be derived by changing the present invention.

The first reflector 20a may be disposed at a first focal point formed by diffracting infrared rays corresponding to a first absorption wavelength of a first target gas. The second reflector 20b may be disposed at a second focal point formed by diffracting infrared rays corresponding to a second absorption wavelength of the second target gas. The third reflector 20c may be disposed at a third focal point formed by diffracting infrared rays corresponding to a third absorption wavelength of a third target gas. At this time, the first absorption wavelength is the longest and the third absorption wavelength is the shortest. The degree of diffraction in the diffracting unit 140 is because the longer the wavelength, the greater the diffraction. The first infrared detector 30a may measure infrared rays reflected by the first reflector 20a. The second infrared detector 30b may measure infrared rays reflected by the second reflector 20b. The second infrared detector 30c may measure infrared rays reflected by the second reflector 20c. Even if the three target gases to be measured are mixed, the concentration of the first target gas can be measured by analyzing the output of the first infrared detector 30a, and the second target gas can be analyzed by analyzing the output of the second infrared detector 30b. The concentration of the gas can be measured, and the concentration of the third target gas can be measured by analyzing the output of the third infrared detector 30c.

The non-dispersive infrared gas sensor 1 formed of the above-described plurality of target gas measurement structures has an effect of measuring a plurality of target gases with one device.

The non-dispersive infrared gas sensor 1 may include a sensor body 40 fixing a multifocal infrared light source 10, a reflector 20, and an infrared detector 30 therein. The sensor body 40 may include an optical pupil 42 through which infrared rays pass, a passage 41 through which gas including the target gas passes, and a separation wall 43 separating the passage 41 and the optical pupil 42. there is. The separating wall 43 may be formed of a material that is transparent to infrared rays.

8 is a view illustrating a movable target gas measuring structure of a non-dispersive infrared gas sensor 1 according to an embodiment of the present invention.

As shown in FIG. 8, in the non-dispersive infrared gas sensor 1 of the present invention, the reflector 20 and the infrared detector 30 are formed to move along the focal point of infrared rays corresponding to the absorption wavelength of the target gas. A moving unit may be further included.

The sensor body 40 may include a focus moving unit. Although not specifically shown in the drawings, the focus moving unit includes various structures capable of separating/assembling, moving, extending, or reducing a part of the sensor body 40 . The focus moving unit may move the reflector 20 and the infrared detector 30 or the multifocal infrared light source 10 to position the reflector 20 at a focal point of infrared light of an arbitrary wavelength. For example, the focus moving unit may be formed so that the reflector 20 and the infrared detector 30 are fixed to move together and move from the multifocal infrared light source 10 in a sliding manner. For example, the focus moving unit may move the multifocal infrared light source 10 and adjust the reflector 20 so that the focal point of the infrared rays of an arbitrary wavelength is located.

As shown in FIG. 8, by moving the reflector 20 and the infrared detector 30 located at the focal point of the infrared rays of the first wavelength, the reflector 20 and the infrared detector 30 are positioned at the focal point of the infrared rays of the second wavelength. can be moved into position.

Since the non-dispersive infrared gas sensor 1 including the focus moving unit can operate the focus moving unit when the target gas is changed, the reflector 20 can be positioned at the focal point of the infrared rays corresponding to the absorption wavelength of the changed target gas. The concentration of various types of target gases can be measured.

The structure having a plurality of reflectors 20 and infrared detectors 30 shown in FIG. 7 and the structure for moving one reflector 20 and infrared detector 30 using a focus moving unit shown in FIG. 8 It can be applied to one non-dispersive infrared gas sensor (1). It is also possible to form a structure in which any one reflector 20 and infrared detector 30 among the plurality of reflectors 20 and infrared detector 30 shown in FIG. 7 are moved using a focus moving unit.

See FIG. 7 again. Infrared light that has passed the focal length widens its optical path again. Since the infrared rays reflected by the first reflector 20 are directed toward the first infrared detector 30, the possibility of being measured by the second infrared detector 30 or the third infrared detector 30 is low. However, infrared rays of a wavelength that is focused at a position between the multifocal infrared light source 10 and the first reflector 20 or focused at a position between the first reflector 20 and the second reflector 20 Infrared light of a wavelength has a possibility of being measured by the first, second, or third infrared detector 30 because the optical path widens again after passing through the focal length, and this problem may cause a measurement error.

The non-dispersive infrared gas sensor 1 according to an embodiment of the present invention may further include an infrared absorption layer 43 so that infrared rays that do not correspond to the absorption wavelength of the target gas do not enter the infrared detector 30. The infrared absorbing layer 43 may be formed of a material that well absorbs infrared rays of various wavelengths. The infrared absorption layer 43 may be formed of a black porous material. The infrared absorbing layer 43 may be formed on an inner surface of the optical pupil 42 of the sensor body 40 or an inner surface of the flow path 41 . Since infrared rays not reflected by the reflector 20 are absorbed by the infrared absorption layer 43, the infrared detector 30 does not detect them. Therefore, the accuracy of the non-dispersive infrared sensor can be improved.

Again refer to FIG. 8 . Infrared light that has passed the focal length widens its optical path again. Infrared rays not reflected by the reflector 20 may be reflected inside the sensor body 40 and then detected by the infrared detector 30, which may cause a measurement error.

The non-dispersive infrared gas sensor 1 according to an embodiment of the present invention may further include a barrier 44 blocking a path for infrared rays that do not correspond to the absorption wavelength of the target gas to enter the infrared detector 30. there is. The barrier rib 44 may be formed on the sensor body 40 to open only an infrared path focused on the reflector 20 . The barrier rib 44 may be coupled with the reflector 20 and the infrared detector 30 and moved together by the focus moving unit. The barrier rib 44 may block a path toward the infrared detector 30 of infrared rays of a wavelength different from the absorption wavelength of the target gas. Therefore, the accuracy of the non-dispersive infrared gas sensor 1 can be improved.

The infrared absorbing layer 43 and the barrier rib 44 described with reference to FIGS. 7 and 8 may be applied together to one non-dispersive infrared sensor. For example, a barrier 44 may be further formed in the sensor body 40 shown in FIG. 7 so as not to obstruct an optical path from the multifocal infrared light source 10 to the third reflector 20. . In the sensor body 40 shown in FIG. 8 , an infrared absorption layer 43 may be formed on a surface of the barrier rib 44 facing the multifocal infrared light source 10 . The barrier rib 44 may be formed to open only light from the reflector 20 toward the infrared detector 30 .

The non-dispersive infrared gas sensor 1 using the above-described multifocal infrared light source 10 focuses infrared rays corresponding to absorption wavelengths of a plurality of target gases at different positions according to absorption wavelengths, and a reflector 20 for each focus ), it is possible to simultaneously measure a plurality of target gases. In addition, since one reflector 20 and the infrared detector 30 can be moved and positioned at the focal point of infrared rays corresponding to the absorption wavelength of the target gas, various target gases can be measured. In addition, even if infrared rays of a wavelength different from the absorption wavelength of the target gas are emitted from the multifocal infrared light source 10, the barrier rib 44 and the infrared absorption layer 43 do not affect the infrared detector 30, so the gas concentration measurement Accuracy can be improved.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, the present invention is not limited thereto, and within the technical spirit of the present invention, by those skilled in the art It will be clear that the modification or improvement is possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific protection scope of the present invention will be clarified by the appended claims.

1: non-dispersive infrared gas sensor 10: multifocal infrared light source
20: reflector 30: infrared detector
40: sensor body 41: gas flow path
42: light hole 110: surface mount unit
111: first substrate 112: first reflective layer
113: first wire bonding pad 114: soldering pad
115: electrode pattern 116: alignment groove
117: dummy pad 120: radiation unit
121: second substrate 122: first cavity
123: membrane 123a: heating area
124: heating pattern 125: second wire bonding pad
126: infrared emitting material 130: reflector
131: third substrate 132: second cavity
133: second reflective layer 140: diffractive portion
141: fourth substrate 142: zone plate pattern
142a: blocking area 142b: passing area
151: wire 152: molding part

Claims (9)

a radiator that emits infrared rays; and
A multifocal infrared light source comprising a diffracting unit for diffracting infrared rays emitted from the radiation unit and focusing them at different distances according to wavelengths. The method of claim 1,
a reflection unit coupled between the radiation unit and the diffraction unit and reflecting the infrared rays in one direction toward the diffraction unit; and
The multifocal infrared light source further includes a surface mounting unit coupled to a lower surface of the radiation unit, reflecting the infrared rays toward the diffracting unit, and having a soldering pad for surface mounting. The method of claim 2,
The surface mounting unit, the radiating unit, the reflecting unit, and the diffracting unit are sequentially disposed and coupled, and sealed to contain an inert gas therein, a multifocal infrared light source. The method of claim 1,
The diffraction part
A multifocal infrared light source formed by printing a zone plate pattern on a substrate formed of a material that transmits infrared rays. The multifocal infrared light source of claim 1;
Among the focal points of infrared rays emitted from the multifocal infrared light source, a reflector disposed at a focal point of infrared rays of an absorption wavelength of a target gas; and
A non-dispersive infrared gas sensor comprising an infrared detector for detecting infrared rays reflected from the reflector. The method of claim 5,
the reflector
In order to measure a plurality of target gases, a plurality of targets are arranged at each focal point of the infrared rays of the absorption wavelength of the plurality of target gases,
The infrared detector
In order to detect infrared rays reflected from the plurality of reflectors, a plurality of disposed, non-dispersive infrared gas sensors. The method of claim 5,
A non-dispersive infrared gas sensor further comprising a focus movement unit formed so that the reflector and the infrared detector move along a focal point of infrared rays corresponding to an absorption wavelength of the target gas. The method of claim 5,
A non-dispersive infrared gas sensor further comprising an infrared absorbing layer so that infrared rays that do not correspond to the absorption wavelength of the target gas do not enter the infrared detector. The method of claim 5,
A non-dispersive infrared gas sensor further comprising a partition wall blocking a path for infrared rays that do not correspond to the absorption wavelength of the target gas to enter the infrared detector.

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