Note: Descriptions are shown in the official language in which they were submitted.
Attorney Ref: 1363P008CA02
INFRARED TEMPERATURE MEASUREMENT AND STABILIZATION
THEREOF
TECHNICAL FIELD
[0001] The present invention relates to infrared (IR) sensors. More
specifically, the present invention relates to IR temperature monitoring
systems.
BACKGROUND
[0002] Infrared (IR) temperature sensors can monitor infrared light
which is
then converted into an electrical signal and ultimately to a temperature
reading. The spectrum of infrared radiation cannot be readily seen by
humans without the use of specially designed equipment that makes the
spectrum visible. Measurement of infrared waves is calibrated in microns,
ranging from 0.7 to 1000 microns. Today, infrared temperature sensors can
be used to measure temperature of almost any type of moving part or object,
including many used related to vehicles.
[0003] One of the most basic IR temperature sensor designs consists of
a
lens that focuses IR energy onto to a detector. The detector can convert the
measured energy to an electrical signal, which can be displayed in units of
temperature. An object's emissivity is used together with the captured energy
in order to convert measured energy into temperature. Today, more
sophisticated sensors can passively compensate for ambient temperature
variations so as to effect accurate measurement of a target object.
[0004] One very useful feature of IR sensors is the ability to measure
temperatures, e.g., without physical contact. This temperature monitoring
ability is especially useful in situations where objects are in motion, e.g.,
in
vehicular
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applications.
Unfortunately, environmental effects upon the sensor require
protective housings and the like to be installed to protect the sensors from
environmental elements. Protective housings and the like include materials
that
vary in temperature and contribute to the IR energy path of the sensor thereby
making accurate and efficient temperature measurements difficult.
[0005] With
regard to conventional IR temperature sensors, significant
measurement errors often occur when the IR sensor, e.g., thermopile, is
subject to thermal conditions such as a wide range in operating temperatures,
temperature rate of change, or static thermal gradients in the sensing region
or path. Any IR visible object in the path between the sensing component and
the measurement target will both deliver energy to the sensor as well as block
a portion of the thermal energy emitted by object target; resulting in
accurate
and inefficient temperature measurement.
BRIEF DESCRIPTION
100061 This brief
description is provided to introduce a selection of
concepts in a simplified form that are described below in the detailed
description. This brief description is not intended to be an extensive
overview
of the claimed subject matter, identify key factors or essential features of
the
claimed subject matter, nor is it intended to be used to limit the scope of
the
claimed subject matter.
[0007] According
to one or more aspects, one or more embodiments
include infrared (IR) temperature measurement and stabilization systems, and
methods related thereto. One or more embodiments actively stabilizes
temperatures of objects in the path between an IR sensor and target object.
A temperature monitor and controller is employed to regulate power to
resistive temperature devices (RTDs) thereby regulating current (and power)
to the RTDs. As a result, temperatures of IR visible objects can be actively
stabilized for changes, for example, changes in ambient temperatures.
[0008] With
regard to traditional infrared (IR) temperature sensors,
significant measurement errors often occur when the IR sensor, e.g.,
thermopile, is subject to thermal conditions such as a wide range in operating
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temperature, temperature rate of change, or static thermal gradients in the
sensing region. IR visible objects in the path between the sensing component
and the measurement target will both deliver energy to the sensor as well as
block a portion of the thermal energy emitted by object target. In accordance
with one or more aspects, intermediate media, such as optical lens and
protective window, are held thermally stable thereby allowing their energy
contributions to be known and precisely compensated for by the measurement
system. As well, other components in the sensing region can be stabilized via
RTDs, e.g., sensor housing, baseplate, etc.
[0009] Accordingly, one or more aspects can deliver a final temperature
indication response time that is significantly reduced by actively stabilizing
the
key measurement components. Temperature compensation, including both
sensor steady-state temperature and rate of change dependencies, can be
significantly reduced or eliminated by actively stabilizing the key
measurement
components by way of RTDs together with temperature control components
and circuitry.
[0010] In other aspects, passive stabilization of temperatures of objects in a
path between a sensor and a target object is provided. In these aspects
passive thermal stabilization is accomplished via conductively coupling the
sensor to optics.
[0011] In one aspect, the innovation provides an IR temperature monitoring
system comprising a sensor assembly encased in an overmolding material.
The overmolded sensor assembly may include an IR temperature sensor
having a sensor housing which encases an IR element. The sensor assembly
may further include a metallic frame that encompasses a transmissive window
in the closed end of the sensor assembly, wherein the metallic frame provides
a stable temperature around the transmissive window.
[0011a] In another aspect, this document discloses an infrared (IR)
temperature monitoring system, comprising: a sensor assembly encased by
an overmolding material, the sensor assembly comprising: an IR temperature
sensor having a sensor housing which encases an IR element, wherein the
overmolding material encases the IR temperature sensor and the sensor
housing; a metallic frame, wherein the metallic frame encompasses a
transmissive window in a closed end of the sensor assembly, wherein the
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metallic frame provides a stable temperature around the transmissive window;
and a resistive temperature detector operative to provide heat to the metallic
frame to stabilize temperature around the transmissive window.
[0011b] In another aspect, this document discloses a method for infrared (IR)
temperature monitoring, comprising: encasing an IR element of an IR
temperature sensor with a sensor housing; encasing the IR temperature
sensor and the sensor housing with an overmolding material to form an
overmolded sensor assembly; and positioning a metallic frame upon an inner
portion of a closed end of the sensor assembly, wherein the metallic frame
encompasses a transmissive window in the closed end of the sensor
assembly, wherein the metallic frame provides a stable temperature around
the transmissive window.
[0011c] In another aspect, this document discloses a method for infrared (IR)
temperature monitoring, comprising: encasing an IR element of an IR
temperature sensor with a sensor housing; encasing the IR temperature
sensor and the sensor housing with an overmolding material to form an
overmolded sensor assembly; and positioning a metallic frame upon an inner
portion of a closed end of the sensor assembly, wherein the metallic frame
encompasses a transmissive window in the closed end of the sensor
assembly, wherein the metallic frame provides a stable temperature around
the transmissive window; an inset molded IR transparent or semi-transparent
lens such that a seamless overmolded seal is achieved between the lens and
the sensor assembly and the lens is in close thermal contact to metallic frame
and sensor element, wherein the overmolding material and the inset molded
IR transparent or semi-transparent lens comprise an infrared-transmitting
material.
[0011d] In another aspect, this document discloses a temperature monitoring
system, comprising: a sensor assembly encased by an overmolding material,
the sensor assembly comprising: a temperature sensor having a sensor
housing which encases an element, wherein the overmolding material encases
the temperature sensor and the sensor housing; a frame, wherein the frame
encompasses a transmissive window, wherein the frame provides a stable
temperature around the transmissive window; and a resistive temperature
detector that stabilizes a temperature around the transmissive window.
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[0011e] In another aspect, this document discloses a method for temperature
monitoring, comprising: encasing an element of a temperature sensor with a
sensor housing; encasing the temperature sensor and the sensor housing with
an overmolding material to form an overmolded sensor assembly; and
positioning a frame upon an inner portion of a closed end of the sensor
assembly, wherein the frame encompasses a transmissive window in the
closed end of the sensor assembly, wherein the frame provides a stable
temperature around the transmissive window.
1001111 In another aspect, this document discloses a method for temperature
monitoring, comprising: encasing an element of an temperature sensor with a
sensor housing; encasing the temperature sensor and the sensor housing with
an overmolding material to form an overmolded sensor assembly; and
positioning a frame upon an inner portion of a closed end of the sensor
assembly, wherein the frame encompasses a transmissive window in the
closed end of the sensor assembly, wherein the frame provides a stable
temperature around the transmissive window, and wherein the sensor housing
forms a lens arranged at one end of the element, the lens being configured
such that a seamless overmolded seal is achieved between the lens and the
sensor assembly and the lens is in close thermal contact to the frame and the
element.
[0012] The following description and annexed drawings set forth certain
illustrative aspects and implementations. These are indicative of but a few of
the various ways in which one or more aspects may be employed. Other
aspects, advantages, or novel features of the disclosure will become apparent
from the following detailed description when considered in conjunction with
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the annexed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Aspects of
the disclosure are understood from the following detailed
description when read with the accompanying drawings. Elements,
structures, etc. of the drawings may not necessarily be drawn to scale.
Accordingly, the dimensions of the same may be arbitrarily increased or
reduced for clarity of discussion, for example.
100141 Fig. 1 is
an illustration of an example infrared (IR) temperature
sensor system capable of component stabilization, according to one or more
embodiments.
[0015] Fig. 2 is
an illustration of an example bottom view of a self-heating
temperature sensor system, according to one or more embodiments.
100161 Fig. 3 is
an illustration of an example top-down view of a self-
heating temperature sensor system, according to one or more embodiments.
[0017] Fig. 4 is
an illustration of an example electrical schematic of
components and circuitry that facilitate temperature stabilization, according
to
one or more embodiments.
[0018] Fig. 5 is
an illustration of an example method for facilitating active
temperature stabilization, according to one or more embodiments.
[0019] Fig. 6 is
an illustration of an example self-heating temperature IR
sensor assembly, according to one or more embodiments.
[0020] Fig. 7 is
an illustration of an example exploded view of an example
sensor assembly, according to one or more embodiments.
[0021] Fig. 8 is
an illustration of an example bottom perspective view of an
example sensor assembly, according to one or more embodiments.
[0022] Fig. 9 is
an illustration of an example side perspective view of an
example sensor assembly, according to one or more embodiments.
[0023] Fig. 10 is
an illustration of an example bottom-up perspective view
of an example sensor assembly, according to one or more embodiments.
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[0024] Fig. 11 is an illustration of yet another example perspective
view of
an assembly, according to one or more embodiments.
[0025] Fig. 12 is an illustration of an example placement of a
conductive
frame, according to one or more embodiments.
[0026] Fig. 13 is an illustration of an example side perspective view
of a
protective housing and circuit board base, according to one or more
embodiments.
[0027] Fig. 14 is an illustration of an example conductive frame,
according
to one or more embodiments.
[0028] Fig. 15 is an illustration of glass fillers positioned onto
leads,
according to one or more embodiments.
[0029] Fig. 16 is an example bottom-up perspective view of an
assembly,
according to one or more embodiments.
100301 Fig. 17 is an illustration of an example infrared (IR)
temperature
monitoring system, according to one or more embodiments.
DETAILED DESCRIPTION
[0031] Embodiments or examples, illustrated in the drawings are
disclosed
below using specific language. It will nevertheless be understood that the
embodiments or examples are not intended to be limiting. Any alterations and
modifications in the disclosed embodiments, and any further applications of
the principles disclosed in this document are contemplated as would normally
occur to one of ordinary skill in the pertinent art.
[0032] As will be described in greater detail infra, one or more
embodiments provides for stabilization of critical measurement components
as well as other 'visible' objects in an infrared (IR) temperature measurement
system. One or more embodiments can effectively stabilize interference
caused by a protective cap or housing as well as other IR 'visible' components
in close proximity to the IR sensor. As will be understood, IR thermal
measurement is highly susceptible to the thermal energy state and flux of both
the sensing element and IR 'visible' media in (and around) the target-object
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path. Active stabilization of the thermal energy or absolute temperature of
these system components is one underlying principal of this disclosure. This
temperature stabilization enhances accuracy and can be performed at an
efficient rate as compared to conventional IR sensor systems.
[0033] Current
sensor assemblies have potential seal vulnerabilities. Such
systems often rely on elements such as covers, glue, plugs, and potting, or a
combination of such elements to provide a protective environment for the
components within the assembly. These seal vulnerabilities may not be ideal
for all environments.
[0034] According
to an aspect of the innovation, an IR temperature system
may comprise an overmolded sensor assembly in which the overmolding
encapsulates and protects components of the sensor assembly. The
overmolded sensor assembly according to the innovation eliminates the need
for a housing seal plug and adhesives or other attachments means for
securing a separate protective cover and, thus, does not have the same
potential seal vulnerabilities.
[0035] In one
aspect of the innovation, the IR temperature system does not
include a separate protective housing. Instead, the components of the sensor
assembly may be overmolded with a protective material. Suitable materials
for overmolding include most any plastic or suitably rigid material. In one
embodiment, the overmolding material may comprise a thermoplastic material
such as a polyamide thermoplastic material. In one embodiment, the
overmolding material may comprise a suitable polymer including acrylonitrile
butadiene styrene (ABS); acetal, high-density polyethylene (HDPE), liquid
crystal polymers (LCPs), polyethylenimine (PEI) ,poly(methyl methacrylate)
(PMMA), polycarbonate (PC), polypropylene (PP), polyphthalamide (PPA),
polyphenylene sulfide (PPS) polystyrene (PS), polysulfone (PSU),
thermoplastic elastomers (TPE), thermoplastic polyurethanes (TPU),
polyether ether ketone (PEEK), or any combination of two or more thereof.
[0036] In one
embodiment, the overmolding may encase all of the
components of the sensor assembly excluding the optical components,
connectors and/or cable exits. Any
configuration of sensor assembly
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components described herein may be encased in the overmolding material
according to embodiments of the innovation.
[0037] In one embodiment, the overmolded sensor assembly may include
a tophat, a sensor element, a sensor PCB, wiring (e.g., exit wires), and an
inset molded IR transparent or semi-transparent lens. In one embodiment,
the overmolding material and the inset molded IR transparent or semi-
transparent lens may comprise an infrared-transmitting material. In one
embodiment, the inset molded IR transparent or semi-transparent lens may
comprise zinc sulfide, silicon, germanium, N-BK7, UV fused silicon, zinc
selenide, sapphire, calcium fluoride, magnesium fluoride, sodium chloride,
potassium bromide, or the like. In one embodiment, the lens may comprise a
material selected from zinc sulfide, silicon, or germanium. In embodiments in
which the lens comprises a different material than the overmolding material,
the overmolding material may be selected from any suitable overmolding
material, including those described above.
100381 Referring initially to the drawings, Fig. 1 illustrates an
example IR
temperature sensor system 100 capable of active component temperature
stabilization. Generally, the system 100 can include a protective housing 102
(e.g., molded plastic cap) having an integral window or lens 104. It will be
appreciated that the lens 104 (e.g., transparent window) enables
measurement of IR energy via IR temperature sensor 106 (e.g., thermopile).
It will be appreciated that this window can be manufactured of the same
material as the protective housing 102. Thus, variations in temperature of the
window 104 effects accuracy of IR measurements until its temperature is
stabilized. It will be appreciated that the window 104 can often represent 30
to 50% of the energy detected by thermopile 106. For at least this reason,
one or more embodiments is capable of stabilizing the temperature of the
window 104 such that compensation can efficiently and effectively be made to
enhance accuracy of the sensing device 106. As shown, the temperature
sensor 106 is equipped with optics 108, which can also vary in temperature
and effect performance of the thermopile 106.
[0039] Because the temperature of the window 104 fluctuates often
during
operation, a heat source is provided to stabilize its temperature thereby
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increasing performance of the IR temperature monitoring functionality.
Additionally, because the window 104 is most often manufactured of plastic,
fluctuations in temperature are slow as plastic is not an efficient conductor
of
heat. An example conductive metal frame equipped with resistive
temperature devices (RTDs) will be described in greater below. This
conductive metal is deposited on the inner side of the protective housing 102
and can focus heat upon the window 104. It will be understood and
appreciated that other aspects can include an optional temperature directional
means (e.g., cone-like device) that captures heat from a conductive source
equipped with RTDs and channels that heat to the window 104 and
components of the sensor 106. In other words, in one or more aspects and
environments, the heating effects and efficiency as described herein can be
affected by the low conductivity of the captive air within the protective
housing. By providing a temperature channeling means, e.g., funnel,
(illustrated as dashed lines 110), heat can be contained within the inner area
of the cone, thereby enhancing stabilization effects.
[0040] It will be
appreciated that measurement system errors of several
degrees exists under current or traditional measurement techniques.
Laborious, time consuming and expensive calibration processes are required
to compensate over varying temperature ranges. Other techniques have
been attempted to passively control temperature of intermediate media using
insulating and conducting materials. Unfortunately, these techniques are
complicated and result in delayed temperature readings. Further, passive
control of intermediate media temperatures oftentimes results in error or
inaccurate readings. It will be appreciated many applications require high
accuracy in IR temperature measurements. The active
temperature
stabilization systems of one or more embodiments can provide this accuracy.
100411
Traditionally, intrinsic errors in IR temperature measurements were
tolerated. Additionally, the optical lens or raw sensor was protected from
environmental elements by looking through narrow chambers or long tubes.
Still further, in accordance with traditional systems, environmentally
protective
barriers were removed as they led to complexity that resulted in inaccurate
readings. Devices took a long time in temperature stable environments to
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indicate accurately.
[0042] In accordance with traditional systems, temperature
compensation
is currently handled by collecting sensor responses over a wide range of
temperatures. Thereafter, the indication is adjusted using sensor unique
correction factors. This is both time consuming and leads to compromised
accuracy. Large thermal masses are added to slow temperature rates of
change and to resolve thermal gradients. Unfortunately, this approach leads
to enhanced device size and longer thermal response times.
[0043] The measurement system 100 of Fig. 1 can actively control the
thermal environment of key components of the IR measurement system.
Following is a review of options available to stabilize temperatures. One
technique of the sensor systems allows the sensor 106 to come into thermal
equilibrium shortly after the environment temperature and heat sources
stabilize. To accomplish this, the thermopile sensor 106 is exposed directly
to
the environment with little or no protection from corrosive or harsh
environments. This direct exposure is needed in order for its temperature to
track the environmental temperature in a reasonable amount of time.
Unfortunately, direct exposure results in damage and corrosive elements
upon the sensor.
[0044] Another alternative technique employs thermal separation of
heat
sources, such as power dissipating electronic components, while enhancing
passive thermal conduction between a protective cover and environmental
media heat transfer. It will be understood that traditional products have
limited performance over wide ambient temperature range.
[0045] Overall, the IR system 100 of Fig. 1 can offer improved
accuracy in
view of conventional systems by way of active temperature stabilization.
Additionally, more accurate temperatures can be rendered in a faster
response time. The system 100 employs simplification that results in reduced
time related to the calibration process. Overall end cost can be reduced in
view of the efficiencies offered by the features, functions, and benefits of
the
disclosure. Still further, the sensor 106 and system 100 can have a wider
application base. Thus, one or more embodiments may provide a versatile
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system adaptable to a wide range of uses or applications.
[0046] Turning now to Fig. 2, a bottom view of an example self-heating
temperature sensor 200 is shown. Item 202 is illustrative of a baseplate of
the
thermopile of Fig. 1. An RTD 204 capable of detecting and generating heat
can be thermally bonded to the baseplate 202. Accordingly, in addition to
detecting thermal power, RTD 204 can also generate heat thereby stabilizing
the temperature of the baseplate 202, along with other components of the
system. Lead apertures 206 are shown and provide means by which
thermopile leads can traverse the baseplate 202 to accompanying circuitry.
[0047] Fig. 3 illustrates a top view of an example stabilization
system 300
in accordance with one or more aspects. Generally, system 300 includes a
protective cover 302 having a lens 304 (or window) provided on the top
surface of the protective cover (302). In aspects, the window 304 is integral
to
the cover however, can also be a separate component in alternative designs.
As described supra, the protective cover 302 encases components of an IR
sensor system (e.g., system 100 of Fig. 1).
[0048] The temperature and temperature movement of the lens 304 (or
window) is effectively noise to the IR detection of the system resulting in
inaccurate readings. In accordance thereto, one or more embodiments
provides for temperature stabilization of the lens 304. Essentially, the lens
304 is an IR transmissive window 304 bordered by a metalized copper (Cu)
frame 306. The frame 306 is deposited upon the inner surface of the
protective cover 302 and can focus heat around the window 304. While a
square frame is shown, it will be understood that other shapes and deposits of
conductive material (e.g., copper) that focus heat upon the window 304 can
be employed without departing from the spirit and/or scope of the disclosure.
Additionally, other conductive metals, e.g., platinum, silver, etc. can be
employed in alternative aspects. Self-heating resistive temperature sensors
308 (e.g., RTDs) can be provided so as to control the self-heating
functionality
of one or more embodiments. It will be understood that the RTDs 308 can
detect and deliver thermal power as appropriate for temperature stabilization.
While two RTDs are shown, other aspects can employ additional or fewer
RTDs as appropriate without departing from the scope of the disclosure or
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claims appended hereto.
100491 Fig. 4
depicts an example electrical schematic 400 in accordance
with one or more aspects. As shown, a self-heating temperature sensor 402
(e.g., RTD) can be electrically coupled to temperature measurement and
temperature control components included within a thermal control circuitry
404. In accordance with a desired temperature setpoint, RTDs 402 can
measure and control temperature by varying power dissipation. In other
words, RTD 402 resistance will represent a certain temperature and the
power provided to the RTD 402 will be proportional to the square root of the
current passing through the RTD 402. In operation, a particular setpoint
temperature can be selected (e.g., 120 F), whereby the RTD can be provided
with a requisite amount of power so as to achieve the desired temperature.
Within the thermal control circuitry 404, the temperature can be measured as
shown. In accordance with this measured temperature, the temperature
control can provide enough power to the self-heating temperature sensor
(RTD) 402 to achieve the temperature setpoint as desired.
[0050] Thus, the
temperature control can vary the power based on a
present and/or desired temperature. Therefore,
heat loss can be
automatically or actively compensated for and stabilized in an active control
of
the thermal environment of the location(s) of the RTD(s). It will be
understood
that this process of regulating temperature can also be utilized with regard
to
all RTDs provided within systems, such as RTDs bonded to conductive metal
within the protective housing as described below.
[0051] Fig. 5
illustrates a methodology 500 of stabilizing components in an
IR temperature measurement system in accordance with one or more
aspects. While, for purposes of simplicity of explanation, the one or more
methodologies shown herein, e.g., in the form of a flow chart, are shown and
described as a series of acts, it will be understood and appreciated that one
or
more acts may, in accordance with one or more aspects, occur in a different
order and/or concurrently with other acts from that shown and described
herein. For example, those skilled in the art will understand and appreciate
that a methodology could alternatively be represented as a series of
interrelated states or events, such as in a state diagram. Moreover, not all
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illustrated acts may be required to implement a methodology in accordance
with one or more aspects.
[0052] At 502, a temperature setpoint can be established. For example,
a
setpoint of 120 F can be selected in aspects so as to exceed most any
ambient operating conditions. As described above, an IR sensor assembly
can be equipped with a number of RTDs so as to actively stabilize component
temperatures. For example, a conductive frame can be equipped with RTDs
so as to focus heat upon a transmissive window in a protective housing.
Similarly, an RID can be bonded to a baseplate of a thermopile and can
provide temperature stabilization.
[0053] At 504, temperature can be monitored via the RTD. As will be
understood, the RTDs employed in connection with one or more aspects can
both monitor and deliver heat as desired. A decision is made at 506 to
determine if the monitored temperature is consistent with the desired
temperature setpoint. If yes, the methodology returns to 504 to monitor the
temperature.
[0054] If not consistent at 506, power to the RID can be regulated at
508.
Thus, the temperature output of the RID can be regulated (e.g., raised) at
510. As will be appreciated, the rise in temperature can effectively regulate
and/or stabilize IR 'visible' components within the protective housing and
within the IR measurement object-target path.
[0055] Referring now to Fig. 6, illustrated is an example self-heating
temperature sensor assembly 600 in accordance with one or more aspects.
As shown in the example of Fig. 6, a protective housing 602 encases
thermopile or sensor 604. For example, the protective housing 602 shelters,
shields and/or safeguards the sensor 604 from environmental effects. A
circuit board 606 is provided upon which sensor 604 can be mounted. It will
be understood and appreciated that circuitry can be disposed upon the board
so as to control the sensor 604 for temperature measurement and thermal
stabilization control via RTDs as described herein. As illustrated, the
circuit
board 606 is of a shape consistent with the protective housing 602. A
metalized frame 608 can be provided and equipped with RTDs that facilitate
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self-heating functionality.
[0056] In one
embodiment, the IR temperature sensor system may include
a sensor assembly encased by an overmolding material. In this embodiment,
the protective housing may be unnecessary as the overmolding material
protects the components of the sensor assembly (e.g., the IR temperature
sensor).
[0057] Fig. 7
illustrates an exploded (and assembled) view of a sensor
assembly 700 in accordance with one or more aspects. As illustrated, the
assembly 700 can include a protective housing 702 that encases sensor
components. In aspects, the protective housing can be manufactured of most
any plastic or suitably rigid material.
100581 The
protective housing 702 shields a sensor housing 704, for
example, from environmental effects. The sensor housing 704 can be
manufactured of stainless steel or most any other suitably rigid material. As
illustrated in Fig. 1 discussed supra, a sensor optic lens 706 can be fitted
atop
the sensor housing 704. The lens
706 is transparent and can be
manufactured of silicon or other suitably transparent or translucent material.
[0059] A
baseplate 708 is disposed upon an end of the sensor housing
706 opposite the lens 706. In aspects, the baseplate 708 is manufactured of
stainless steel. However, it will be understood and appreciated that most any
suitable material can be employed without departing from the spirit and/or
scope of the disclosure or claims appended hereto. A resistive temperature
detector (RTD) 710 can be mounted or thermally bonded beneath the
baseplate 708, thereby temperature stabilization of components (e.g.; 708,
706, and 704) can be effected via RTD 710. In aspects, RTD 710 can be a
ceramic RTD.
[0060] The RTDs
may be capable of use in a mode that can measure
temperature and deliver heat simultaneously. Thus, this single component
(e.g., RTD) is capable of functionally measuring temperature while at the
same time working to stabilize temperatures of other IR 'visible' components
(e.g., housing, baseplate, optic lens, protective housing window, etc.). The
RTDs can be controlled by a circuit that facilitates maintenance of a
particular
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temperature or setpoint (e.g., 120 F).
[0061] Accordingly, the circuitry can regulate power to the RTD to
maintain
the desired temperature. While specific temperatures and power sources are
described herein, the features, functions, and benefits may be employed to
maintain most any desired temperature by providing power or wattage as
appropriate. It will be appreciated that stabilization of the critical
component's
temperature enhances accuracy and performance of the IR temperature
sensing functionality.
[0062] As illustrated, glass fillers 712 can be fitted into holes of
the
baseplate 708. The glass fillers 712 can enhance the hermetic seal in
addition to the seal of the protective housing 702 mounted onto the circuit
board 718. Upon manufacture, leads, e.g., copper leads, 714 can be inserted
through the glass fillers 712 and into the baseplate 708. A trace, e.g.,
copper
trace, 716 can be provided in embodiments. A circuit board 718 can be fitted
onto the open end of the protective housing 702, thereby encasing sensor
components therein. It will be appreciated that the circuit board 718 can be
of
a shape consistent with an open end of the protective housing 702. In other
aspects, a groove that is consistent with the shape of the open end of
protective housing 702 can be provided so as to provide a suitable hermetic
seal.
[0063] Also included within the protective housing 702 is a metalized
frame, e.g., copper frame, 720. The copper frame 720 can be equipped with
RTDs 722. In one aspect, RTDs 722 are ceramic detectors. While RTD 710
can detect temperature and provide heat to the baseplate 708 region, the
RTDs 722 can provide heat to the protective housing window region as
shown. It will be appreciated that the RTDs 722 can provide heat to the
metalized frame which can conduct heat around the window. By focusing
heat upon the window, temperature can be evenly stabilized to enhance IR
measurement functionality.
[0064] Fig. 8 is a bottom perspective view of an example sensor
assembly
800 in accordance with one or more aspects. As shown, the sensor assembly
800 can include overmolding 802, a circuit board 804 and an RTD
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806. Additionally copper leads 808 are provided so as to facilitate electrical
connection as appropriate.
[0065] Referring now to Fig. 9, a side perspective view of an example
sensor assembly 900 is shown. As illustrated, protective housing 902 can be
equipped with a translucent window 904 on the top such that IR energy can
be captured via a sensor or thermopile. The bottom section of the protective
housing 902 is open such that sensor components can be inserted as
described with regard to Fig. 7 supra. Further, the open end of the protective
housing 902 can be configured to mate to a circuit board 906, e.g., providing
a
waterproof or hermetic seal. It will be understood that, where appropriate,
gaskets can be provided to assist with or enhance the sealing functionality.
100661 Fig. 10 illustrates a bottom-up perspective view of an example
sensor assembly 1000 in accordance with aspects. From this vantage point,
placement of glass fillers 1002 can be can be seen. In other words, each of
the leads 1004 is passed through a glass filler 1004 upon insertion into the
circuit board 1006.
[0067] Fig. 11 is yet another perspective view of an assembly 1100 in
accordance with aspects. As shown, a sensor component 1102 can be
disposed within the center of circuit board 1104. In other aspects, the sensor
component 1102 can be mounted upon an end cap that does not include
circuitry. In these alternative aspects, the circuitry can be remotely located
from the thermopile. It will be appreciated that this illustration is
exemplary
and not intended to limit alternative aspects disclosed herein.
[0068] Fig. 12 illustrates an example 1200 placement of a frame 1202
within the closed face of protective housing 1204. In other words, the metal,
e.g., copper, frame 1202 is encased within the protective housing 1204
together with other sensor components as described in greater detail supra.
Further, the metal frame 1202 can be equipped with RTDs 1206 as shown.
These RTDs 1206 can provide information necessary for temperature
stabilization in accordance with the features, functions, and benefits of the
disclosure. As well, the RTDs 1206 can provide heat as necessary for
stabilization effect.
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[0069] Fig. 13 to Fig. 16 are shown in accordance with one or more
aspects. While specific heat capacities and conductivities are disclosed, it
will
be understood that these values and parameters are provided for perspective
and are not limiting in any manner.
[0070] Referring first to the assembly 1300 of Fig. 13, protective
housing
1302, e.g., plastic, can have a specific heat capacity of 2200 J/Kg K and a
conductivity of 0.5 W/m K. Circuit board 1304 can have a specific heat
capacity of 1200 J/Kg K and a conductivity of 0.23 W/m K.
[0071] The frame 1400 of Fig. 14 can have a specific heat capacity of
385
J/Kg K and a conductivity of 398 W/m K. The glass fillers 1502 of Fig. 15
can have a conductivity of 0.836 W/m K, as seen at 1500.
[0072] As shown in the assembly 1600 of Fig. 16, a sensor housing
1602,
e.g., steel housing, can have a specific heat capacity of 477 J/Kg K. The
sensor housing 1602 can also have a conductivity of 16.7 W/m K in aspects.
Consistent with the sensor housing 1602, the baseplate 1604, e.g., steel, can
have a specific heat capacity of 477 J/Kg K and a conductivity of 16.7 W/m
K. The leads 1606, e.g., copper leads, can have a specific heat capacity of
385 J/Kg K and a conductivity of 398 W/m K.
[0073] In accordance with one or more aspects, it will be understood
that
heat transfer is a through conduction in a component and wherever two
components come into contact. The outer surface of the protective housing
can convect with the ambient temperature. The inner surface of the protective
housing and the outer surface of the other components within the protective
housing (e.g., sensor housing) will convect with the captive air that is
trapped
inside the protective housing. In embodiments, convective heat transfer
coefficient of 7.9 W/MA2 K is used.
[0074] In accordance with the aforementioned heat capacities and
conductivities, a power source of 0.196W was specified at each RTD. The
ambient temperature was fixed as ¨20 C. Upon testing, a power source of
0.196W was applied at each RTD. The RTDs at the copper frame to reached
a temperature of about 120 F. The temperature at RTD near the baseplate
for this power is 101 F. It will be understood that this amount of
stabilization
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is sufficient to enable efficient and accurate IR temperature measurements.
In other words, control circuitry can be provided so as to use the stabilized
component temperatures in IR energy to temperature conversions. As a
result, effects of IR 'visible' components are alleviated.
[0075] While
active stabilization has been disclosed and described in detail
herein, it will be understood that passive (or combinations of active and
passive) stabilization embodiments are to be contemplated and included
within the scope of the disclosure and claims appended hereto. For instance,
in a passive embodiment, the sensor component(s) may be thermally coupled
to the optics so as to effect passive stabilization. In other words, the cover
(e.g., including optics) can be metalized using a conductive material (e.g.,
copper). Here, the
passive conductivity of thermal properties via the
conductive metal can be used to stabilize the temperature(s) as described
herein.
100761 Fig. 17 is
an illustration of an exploded view of an example infrared
(IR) temperature monitoring system 1700, according to one or more
embodiments. The system 1700 may provide for passive temperature
stabilization by thermally bonding a protective housing 1702 or protective
shell, such as a protective plastic housing, to a sensing element 1712. In one
or more embodiments, the protective housing 1702 has an open end and a
closed end. The protective housing 1702 may be formed of a non-thermally
conductive, corrosion resistant material. Additionally, the protective housing
1702 may have an integral thin window 1710 of IR transmissive plastic. As
seen in Fig. 17, the open end of the protective housing 1702 may couple with
a frame, which may be formed of metal. For example, the frame 1704 may be
a metallic frame or a conductive frame having an open top hat shape. It will
be appreciated that the frame 1704 may be inset formed, bonded, or pressed
to fit firmly against the closed end face of the protective housing 1702. The
frame 1704 may be positioned upon an inner face or portion of the closed end
of the protective housing 1702. In other words, the frame 1704 may be
pressed into tight contact with the protective housing 1702 effectively
stabilizing the otherwise non-conductive plastic window. The cylinder end
may fit snuggly around the IR element 1712 or sensor element. In one or
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more embodiments, the snug fit may further be enhanced by the use of
thermal grease or thermally conductive adhesive. The top hat in situ then
thermally stabilizes and maintains a uniform temperature between the outside
media and the sensing element 1712. Further stated, the frame 1704 may
encompass a transmissive window in the closed end of the protective housing
1702 to facilitate providing a stable temperature around the transmissive
window. Additionally, the assembly or system 1700 may include an infrared
(IR) element, such as a thermopile IR detector 1712, a circuit or signal
processor 1714, and a housing plug 1716 or housing seal plug.
100771 In one or
more embodiments, a sensor assembly may include the
IR element 1712, the signal processor 1714, and the housing seal plug 1716,
which seals the system 1700. Accordingly, the system 1700 may include the
protective housing 1702, the frame 1704, and the sensor assembly. It will be
appreciated that one or more of the components described herein may be
bonded and/or sealed for harsh environment use. In other
words,
components 1702 and 1704 may be thermally coupled with 1712, 1714, and
1716 such that a temperature of a protective housing lens (e.g., within the
protective housing 1702) does not disrupt an intended temperature, setpoint
temperature, or target temperature measurement. In this way, the system
1700 links a temperature of an outside environment or enables an outside,
external, or ambient temperature measurement to be made. Further, lens
temperature compensation may be provided as well.
[0078] According
to one or more aspects, infrared (IR) temperature
monitoring system is provided, including a protective housing, an IR
temperature sensor, and a metallic frame. The protective housing may have
an open end and closed end. The IR temperature sensor may have a sensor
housing which encases an IR element. The protective housing may encase
the IR temperature sensor and the sensor housing. The protective housing
may be a cap that shields the sensor housing from one or more environmental
effects. The metallic frame may be positioned upon an inner portion of the
closed end of the protective housing, wherein the metallic frame
encompasses a transmissive window in the closed end of the protective
housing, wherein the metallic frame provides a stable temperature around the
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transmissive window.
[0079] In one or more embodiments, the protective housing encases the
IR
temperature sensor. The IR element may be positioned on a signal
processor. The metallic frame may be a conductive top hat. The system may
include a housing seal plug. The protective housing may be cylindrical in
shape or formed of plastic. The metallic frame may be formed of copper,
aluminum, or other suitable thermal conductor / thermally conductive material.
The sensor housing may be formed of plastic that acts as a lens arranged at
one end of the IR element and a baseplate mounted to the other end of the IR
element. The system may include one or more glass fillers that hermetically
seal one or more leads traversing through a baseplate of the IR element.
100801 According to one or more aspects, a method for infrared (IR)
temperature monitoring is provided, including encasing an IR element of an IR
temperature sensor with a sensor housing, encasing the IR temperature
sensor and the sensor housing with a protective housing having an open end
and closed end, wherein the protective housing is a cap that shields the
sensor housing from one or more environmental effects, and positioning a
metallic frame upon an inner portion of the closed end of the protective
housing, wherein the metallic frame encompasses a transmissive window in
the closed end of the protective housing, wherein the metallic frame provides
a stable temperature around the transmissive window. The protective
housing may include an integral lens formed of the same material as the
protective housing. The IR element may be positioned on a signal processor.
The signal processor may be implemented as a circuit. The housing plug or
housing seal plug may fit with the assembly 1700 of Fig. 17 to complete an
internal system seal impervious to one or more environmental effects.
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[0081] According to one or more aspects, an infrared (IR) temperature
monitoring system is provided, including a protective housing having an open
end and closed end, an IR temperature sensor having a sensor housing which
encases an IR element, wherein the protective housing encases the IR
temperature sensor and the sensor housing, wherein the protective housing is
a plastic cap that shields the sensor housing and the IR temperature element
from one or more environmental effects, a metallic frame positioned upon an
inner portion of the closed end of the protective housing, wherein the
metallic
frame encompasses a transmissive window in the closed end of the protective
housing, wherein the metallic frame provides a stable temperature around the
transmissive window, and a housing seal plug which completes an internal
system seal impervious to external environment effects.
[0082] Although the subject matter has been described in language
specific to structural features or methodological acts, it will be understood
that
the subject matter of the appended claims is not necessarily limited to the
specific features or acts described above. Rather, the specific features and
acts described above are disclosed as example embodiments.
[0083] Various operations of embodiments are provided herein. The
order
in which one or more or all of the operations are described should not be
construed as to imply that these operations are necessarily order dependent.
Alternative ordering will be appreciated based on this description. Further,
not
all operations may necessarily be present in each embodiment provided
herein.
[0084] As used in this application, "or" is intended to mean an
inclusive "or"
rather than an exclusive "or". Further, an inclusive "or" may include any
combination thereof (e.g., A, B, or any combination thereof). In addition, "a"
and "an" as used in this application are generally construed to mean "one or
more" unless specified otherwise or clear from context to be directed to a
singular form. Additionally, at least one of A and B and/or the like generally
means A or B or both A and B. Further, to the extent that "includes",
"having",
"has", "with", or variants thereof are used in either the detailed description
or
the claims, such terms are intended to be inclusive in a manner similar to the
term "comprising".
Date Recue/Date Received 2022-04-14
Attorney Ref.: 1363P0080A02
[0085] Further,
unless specified otherwise, "first", "second", or the like are
not intended to imply a temporal aspect, a spatial aspect, an ordering, etc.
Rather, such terms are merely used as identifiers, names, etc. for features,
elements, items, etc. For example, a first channel and a second channel
generally correspond to channel A and channel B or two different or two
identical channels or the same channel.
Additionally, "comprising",
"comprises", "including", "includes", or the like generally means comprising
or
including, but not limited to.
[0086] Although
the disclosure has been shown and described with
respect to one or more implementations, equivalent alterations and
modifications will occur based on a reading and understanding of this
specification and the annexed drawings. The disclosure includes all such
modifications and alterations and is limited only by the scope of the
following
claims.
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