Patent Publication Number: US-11665795-B2

Title: Thermally protected low profile LED luminaire

Description:
FIELD 
     The present subject matter relates generally to luminaires used in enclosed environments, such as indoor luminaires used in closets. 
     BACKGROUND 
     Light fixtures can be used to provide lighting for a space, such as a building or room. Light emitting diode (LED) devices and other solid state devices are becoming increasingly used in many lighting applications and have been integrated into a variety of lighting fixtures. Use of LED light sources in light fixtures can provide increased efficiency, life and durability, can produce less heat, and can provide other advantages relative to traditional incandescent and fluorescent lighting systems. Moreover, the efficiency of LED light sources has increased such that higher power can be provided at lower cost to the consumer. 
     The use of LED light sources has allowed for the provision of “low profile” light sources. These low profile light sources can be surface mounted to a ceiling or other surface adjacent to a junction box or can housing of a can lighting fixture. The shallow depth of the low profile lighting fixtures can reduce the intrusion of the lighting fixture from the surface into the space. To accommodate their shallow depth, low profile lighting fixtures often include a single circuit board that includes both the LED devices as well as other electronic components for driver circuits used to power the LED devices. 
     SUMMARY 
     According to certain aspects, a lighting fixture includes a fixture housing. A circuit board is positioned in the fixture housing. The circuit board includes a driver circuit. A plurality of light emitters are disposed on the circuit board. The light emitters are operatively connected to the driver circuit to produce a light output. A temperature sensor is disposed on the circuit board. The temperature sensor is configured to measure a temperature of the circuit board and output a signal. The driver circuit is configured to reduce the light output in response to the signal from the temperature sensor. 
     According to certain aspects, a lighting fixture includes a fixture housing. A circuit board is positioned in the fixture housing. The circuit board includes a driver circuit. A reflector extends between the circuit board and the fixture housing. The reflector has a central portion and a sensor housing extending from the central portion. A plurality of light emitters are disposed on the circuit board. The light emitters are operatively connected to the driver circuit to produce a light output. A temperature sensor is connected the circuit board and extends into the sensor housing. The temperature sensor is configured to measure a temperature of the circuit board and output a signal. The driver circuit is configured to reduce the light output in response to the signal from the temperature sensor. 
     According to certain aspects, a lighting fixture includes a fixture housing. A circuit board is positioned in the fixture housing. A plurality of light emitters disposed on a first portion of the circuit board. A driver circuit is disposed on a second portion of the circuit board. The driver circuit is operatively connected to the light emitters to produce a light output. A temperature sensor is disposed on the first portion of the circuit board. The temperature sensor is configured to measure a temperature of the circuit board and output a signal. The driver circuit is configured to reduce the light output in response to the signal from the temperature sensor. The first portion of the circuit board is spaced from the second portion of the circuit board. The first portion is positioned closer to a center of the circuit board than the second portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aspects and features of various exemplary embodiments will be more apparent from the description of those exemplary embodiments taken with reference to the accompanying drawings. 
         FIG.  1    depicts a side view of an exemplary light fixture. 
         FIG.  2    depicts a bottom view of the light fixture of  FIG.  1   . 
         FIG.  3    depicts a top, perspective view of the light fixture of  FIG.  1   . 
         FIG.  4    depicts a top view of the light fixture of  FIG.  1   . 
         FIG.  5    depicts an exploded view of the light fixture of  FIG.  1   . 
         FIG.  6    depicts an exemplary circuit board layout for the LED circuit board to be used in the light fixture of  FIG.  1   . 
         FIG.  7    depicts aside view of the circuit board of  FIG.  6   . 
         FIG.  8    depicts aside view of another exemplary light fixture. 
         FIG.  9    depicts a top perspective view of the light fixture of  FIG.  1    and a mounting bracket. 
         FIG.  10    depicts an exploded view of the light fixture of  FIG.  8   . 
         FIG.  11    depicts a sectional view of  FIG.  1   . 
         FIG.  12    depicts a top perspective view of a reflector. 
         FIG.  13    depicts a bottom perspective view of  FIG.  12   . 
         FIG.  14    depicts a bottom view of the light fixture of  FIG.  8    with the housing and lens removed. 
         FIG.  15    depicts a bottom view of the light fixture of  FIG.  8    with the housing, lens, and reflector removed. 
         FIG.  16    depicts a bottom perspective view of another light fixture showing a circuit board layout. 
         FIG.  17    is a schematic circuit diagram of temperature monitored LED array utilizing a drive circuit and an NTC thermistor. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Various exemplary embodiments are directed to low profile lighting fixtures having one or more light emitting diode (LED) devices. An example low profile light fixture can be configured to be surface mounted (e.g., a ceiling or wall mounted) in a manner that covers a junction box or a recessed can housing. The low profile light fixture utilizes one or more light emitting diode (LED) devices, or other light sources, to produce a light output. The LEDs can be integrated with a circuit board. The circuit board can further include electronic components for providing and/or conditioning power to the LED devices, including larger electronic components associated with, for instance, a filter circuit and/or a flicker reducing circuit. In some embodiments, all of the electronic components and LED devices associated with the low profile lighting fixture are disposed on the same circuit board. For example, no separate driver or control circuit is needed. In some examples, the electronic components for providing and/or conditioning power to the LED devices can be arranged on the circuit board relative to the LED devices in a manner that reduces shadowing effects when the LED devices become illuminated, providing a more uniform output of light from the lighting fixture. 
     For example, a lighting fixture can include a fixture housing. The fixture housing can be circular in shape, rectangular in shape, square in shape, or can have other suitable shapes. The fixture housing can have a length dimension (e.g., a long dimension in the case of a rectangular shape, a diameter in the case of a circular shape, etc.). The fixture housing can also have a depth dimension. The depth dimension can be indicative of how far the lighting fixture extends from a surface when the lighting fixture is mounted to the surface. In some embodiments, a ratio of the length dimension to the depth dimension is about 0.25 or less. As used herein, the use of the term “about” in conjunction with a numerical value is intended to refer to within 25% of the stated numerical value. 
     The light fixture can include a single circuit board (e.g., a circuit board associated with a light engine) that includes a plurality of LED devices and a plurality of electronic components for providing and/or conditioning power or the LED devices. For instance, the electronic components can be associated with a driver circuit and/or a filter circuit. In some embodiments, the driver circuit can include AC-DC power conversion and current reduction. In some embodiments, the filter circuit can be associated with a flicker reducing circuit. The flicker reducing circuit can include one or more capacitors for filtering power signals for driving the LED devices. 
     The LED devices can be located on a first portion of the circuit board and the one or more electronic components can be located on a second portion of the circuit board that is separated from the first portion of the circuit board. For instance, in some embodiments, the second portion of the circuit board can be spaced radially apart from a center point on the circuit board relative to the first portion. In some embodiments, the second portion of the circuit board can at least partially surround the first portion of the circuit board. In some embodiments, the first portion of the circuit board can be located at a center portion of the circuit board and the second portion of the circuit board can be located at a peripheral portion of the circuit board. In some embodiments, none of the electronic components associated with the driver circuit and/or filter circuit are located in the first portion of the circuit board. 
     By separating the electronic components associated with the driver circuit, filter circuit, and/or flicker reducing circuit from the LED devices on the circuit board, the LED devices can provide illumination without interference from the electronic components with the light output from the LED devices. In this way, potential shadows that may have resulted from the one or more electronic components, particularly larger electronic components (e.g., capacitors) associated with, for instance, a flicker reducing circuit can be reduced. 
       FIGS.  1 - 5    depict a light fixture  100  according to exemplary embodiment of the present disclosure. The light fixture  100  can be a surface mount, low profile light fixture. The light fixture  100  can include a fixture housing  110 . The fixture housing  110  can be adapted to be surface mounted to a ceiling, wall, or other surface. 
     The fixture housing  110  illustrated in  FIGS.  1 - 5    is generally conical in shape. Those of ordinary skill in the art, using the disclosures provided herein, will understand that the lighting fixture  100  can include various curvilinear and rectilinear shapes and cross-section, without deviating from the scope of the present disclosure, such as rectangular shape, a square shape, a triangular shape, a polygonal shape, a spherical shape, etc. 
     The fixture housing  110  can include a length dimension L and a depth dimension D. The length dimension L can be, for instance, the diameter of a generally circular lighting fixture as shown in  FIG.  1   . The length dimension L can also be a dimension associated with a line that passes through a center point of the fixture housing  110  and having ends on a peripheral portion of the fixture housing  110 . 
     The depth dimension D can be associated with a distance from a top portion of the fixture housing  110  to a bottom portion of the fixture housing  110  when the fixture housing is oriented as shown in  FIG.  1   . The depth dimension D can represent a distance that the fixture housing  110  extends from a surface to which the lighting fixture  100  is mounted. 
     According to example embodiments of the present disclosure, the lighting fixture  100  can be a low profile lighting fixture such that the depth dimension does not extend a far distance from the surface to which it is mounted. In some embodiments, a ratio of the depth dimension D to the length dimension L can be about 0.25 or less, such as about 0.18 or less. 
     In some embodiments, the light fixture  100  can include one or more spring clips  200  that can engage a bracket  210  in order to mount the light fixture  100  to a ceiling or other support. For instance, the bracket  210  can be secured to a junction box recessed within a ceiling. The spring clip  200  can engage the bracket  210  (e.g., by being inserted through an opening in the bracket  210 ) to retain the fixture  100  adjacent the surface. The spring clips  200  can form a rotatable connection with the bracket  210  so that the position of the light fixture  100  can be rotatably adjusted relative to the support. Other suitable mounting techniques can be used without deviating from the scope of the present disclosure. 
     The light fixture  100  can include a waterproof gasket  120 . The waterproof gasket  120  can provide a seal between a surface to which the lighting fixture  100  is mounted and the fixture housing  110  so that dust, moisture, water, and/or other elements are prevented from entering the interior of the fixture housing  110 . In this way, internal components (e.g., circuit board  300 ) can be protected from damage from external sources. 
     The light fixture  100  can include a silicone (e.g., silicone rubber) ring  125  and a lens  142  positioned in the housing  110 . The lens  142  can be used to protect internal components of the lighting fixture (e.g., circuit board  300 ) and/or to condition light emitted from one or more LED devices mounted on circuit board  300  to provide a desired light output for the lighting fixture  100 . The lens  142  can be, for instance, a glass, polycarbonate, acrylic, or silicone lens (with or without UV protection) or other suitable lens. 
     As shown in  FIGS.  5  and  6   , the light fixture  100  can include a circuit board  300  having one or more LED devices as light sources for the light fixture  100 . The circuit board  300  can be mounted on a heat sink  130  that is configured to transfer heat away from the circuit board  300 . The heat sink  130  can include any suitable heat conducting material, such as a metal material. In some embodiments, the heat sink  130  can be integrally formed with the circuit board  300 . 
     The circuit board  300  can be associated with a light engine that includes all of the necessary electronic components for powering the one or more LED devices located on the circuit board  300 . For instance, the circuit board  300  can include one or more electronic components associated with a driver circuit configured to convert an input power (e.g., an input 120 V AC power) to a suitable DC power for driving the LED devices. In some embodiments, the driver circuit can be a dimmable driver circuit. The driver circuit can include various components, such as switching elements (e.g. transistors) that are controlled to provide a suitable driver output. For instance, in some embodiments, the driver circuit can include one or more transistors. Gate timing commands can be provided to the one or more transistors to convert the input power to a suitable driver output using pulse width modulation techniques 
     The circuit board  300  can also include electronic components (e.g., semiconductor chips, capacitors, etc.) associated with a filter circuit used as part of, for instance, a flicker reducing circuit. The filter circuit can smooth power signals provided from the driver circuit so that light flicker in light emitted from the LED devices on the circuit board  300  is reduced. In some embodiments, a flicker reducing circuit can include one or more capacitors that are used to smooth the driver output of a driver circuit implemented on the circuit board  300 . In some embodiments, a flicker reducing circuit can include one or more integrated circuit chips (e.g., application specific integrated circuits) that control various electronic components (e.g., transistors) based on input signals from the driver circuit to reduce light flicker in light emitted from the LED devices on the circuit board  300 . 
     In some embodiments, the electronic components associated with a driver circuit and a flicker reducing circuit are located on the same circuit board  300  so that only one circuit board has to be included in the lighting fixture  100 . This can allow for the fixture housing  110  to have a reduced depth relative to housings configured to accommodate multiple circuit boards, allowing the lighting fixture  100  to be more easily implemented as a low profile lighting fixture. 
       FIG.  6    depicts an example circuit board layout for circuit board  300  according to example embodiments of the present disclosure. As shown, the circuit board  300  includes a plurality of LED devices  302 . The LED devices  302  are arranged as a circular array in a first portion  310  of the circuit board  300 . The circuit board  300  also includes electronic components for providing and conditioning power to the plurality of LED devices  302 . For instance, the circuit board  300  can include electronic components associated with a driver circuit and one or more filter circuits (e.g., including one or more capacitors). The filter circuit(s) can be associated with, for instance, a flicker reducing circuit for reducing flicker in the light output of the LED devices  302 . In some embodiments, the LED array can correspond to the shape of the housing, for example a rectangular LED array can be used with a rectangular lighting fixture. 
     As shown in  FIG.  6   , the electronic components can include, for instance, a fuse  331 , capacitors  322 , integrated circuits  324 , and other electronic components. Some electronic components can extend a greater distance from the circuit board  300  relative to the LED devices  302 . For instance, as shown in  FIG.  7   , an LED device can extend a first distance d 1  from the circuit board  300  and a capacitor  322  associated with, for instance, a flicker reducing circuit can extend a distance d 2  from the circuit board. The distance d 2  can be greater than the distance d 1 , for example at least two times greater than the distance d 1 , at least four times greater than the distance d 1 , or at least ten time greater than the distance d 1 . 
     Referring to  FIG.  6   , the electronic components associated with driver circuit and flicker reducing circuit can be located in a second portion  320  of the circuit board. The second portion  320  of the circuit board  300  can be disposed in a separate location of the circuit board  300  relative to the first portion  310  of the circuit board  300  such that none of the electronic components associated with the driver circuit or the flicker reducing circuit are located in the first portion  310  of the circuit board  300 . In the example of  FIG.  6   , the first portion  310  of the circuit board  300  can be located in a center portion of the circuit board  300 . The second portion of the circuit board  300  can be located in a peripheral portion of the circuit board  300 . 
     As shown in  FIG.  6   , the second portion  320  of the circuit board  300  is spaced radially apart in the radial direction R from a center point  330  on the circuit board  300 . As used herein, the term “spaced radially apart” is not limited to generally circular structures but can refer to being spaced away from a central portion of the circuit board  300  towards a peripheral portion of the circuit board  300  irrespective of the shape of the circuit board  300 . As shown in  FIG.  6   , the second portion  320  of the circuit board at least partially surrounds the first portion  310  of the circuit board  300  such that the electronic components associated with the driver circuit and/or filter circuit at least partially surround the circular array of LED devices  302 . 
     In this way, the electronic components (e.g., fuse  331 , capacitors  322 , integrated circuit  324 , and other components) associated with the driver circuit and the flicker reducing circuit can be positioned on the circuit board  300  at a location that does not interfere with light emitted from the LED devices  302 . This can reduce shadowing effects in the light output from the lighting fixture  100  that may result from certain electronic components of the flicker reducing circuit or driver circuit (e.g., one or more capacitors) that can extend a greater distance from the circuit board  300  relative to the LED devices. 
     In certain embodiments, the temperature of the lighting fixture  100  may need to be regulated. LED devices  302  are known to produce heat, and an excessive output of this heat can transfer to the housing  110  and lens  142 . This heat transfer can lead to unsafe conditions, especially in enclosed locations and where the light fixture  100  may come in contact with flammable material. For example, a low profile light fixture positioned in a closet or storage area may come in contact with material stacked on a shelf. If the material is flammable, prolonged contact can cause the material to ignite. 
     In order to prevent unsafe overheating, a temperature sensor can be operatively connected to the circuit board  300 , and the circuit board  300  can be configured to reduce the output of the LED devices  302  if the sensor detects that one or more components of the lighting fixture approaches or reaches a maximum temperature. The sensor can monitor an external temperature of the lighting fixture  100  (e.g., the housing  110  or the lens  142 ), an internal temperature (e.g., the circuit board  300 ), or any combination thereof. Different temperature sensing devices can be used, including diodes, chip sensors, thermistors (e.g., PTC and NTC thermistors), and resistance temperature detectors. 
     The output of the LED devices  302  can be reduced from a first set amount to a second amount after passing or approaching one or more temperature thresholds. The output can be decreased in steps, a continuous linear amount, a continuous curved amount, or any combination therefore. The total decrease in output can be anywhere below 100% of the maximum output to 0% of the maximum output, or completely off. In some exemplary embodiments, the maximum temperature can be below 90 degrees Celsius. In some exemplary embodiments, the maximum temperature can be below 60 degrees Celsius. In some embodiments, the maximum temperature is between approximately 60-90 degrees Celsius. 
     According to an exemplary embodiment, as shown in  FIG.  6   , a temperature sensor  332  is mounted directly to the circuit board  300 . The temperature sensor  332  can be a solid-state sensor that measures the temperature of the circuit board  300  and converts the temperature input into a proportional current output. The circuit board  300  can be configured so that at a set point the current output of the sensor  332  will trigger a reduction in the light output in any manner described above. Other types of contact and non-contact temperature sensors can be used (e.g., thermistor, resistance temperature detector, thermocouple, infrared). It is also noted that the concept of incorporating a temperature sensor on a printed circuit board for reducing light output at a set temperature can be incorporated into other light fixtures. 
       FIGS.  8 - 15    depict alight fixture  400  according to exemplary embodiment of the present disclosure. The light fixture  400  can be a surface mount, low profile light fixture. The light fixture  400  can include a fixture housing  402 . The fixture housing  402  can be adapted to be surface mounted to a ceiling, wall, or other surface. 
     The illustrated embodiment of the fixture housing  402  is generally conical in shape. Those of ordinary skill in the art, using the disclosures provided herein, will understand that the lighting fixture  100  can include various curvilinear and rectilinear shapes and cross-section, without deviating from the scope of the present disclosure, such as rectangular shape, a square shape, a triangular shape, a polygonal shape, a spherical shape, etc. In certain embodiments the length dimension and depth dimension discussed above in connection to the light fixture  100  of  FIGS.  1 - 5    can apply here. 
     As best shown in  FIG.  9   , the light fixture  402  can include one or more spring clips  404  that can engage a bracket  406  in order to mount the light fixture  400  to a ceiling or other support. For instance, the bracket  406  can be secured to a junction box recessed within a ceiling. The spring clip  404  can engage the bracket  406  (e.g., by being inserted through an opening in the bracket  210 ) to retain the fixture  400  adjacent the surface. The spring clips  404  can form a rotatable connection with the bracket  406  so that the position of the light fixture  400  can be rotatably adjusted relative to the support. Other suitable mounting techniques can be used without deviating from the scope of the present disclosure. 
       FIGS.  10  and  11    shows exemplary components associated with the light fixture  400 . The light fixture  400  can include a lens  408 , a gasket  410 , a reflector  412 , a circuit board  414  having one or more light emitters  416  (e.g., LEDs) and one or more electrical components  418  for controlling the light emitters  416 , and a backing member  420 . 
     The lens  408  can be used to protect internal components of the lighting fixture and/or to condition light emitted from one or more light emitters  416  mounted on circuit board  414  to provide a desired light output for the lighting fixture  400 . The lens  408  can be, for instance, a glass, polycarbonate, acrylic, or silicone lens (with or without UV protection) or other suitable lenses. The lens can extend through a bottom opening in the housing  402  and can incorporate a connection with a gasket or other sealing member to help prevent ingress of water, dust, bugs, or other contaminates. 
     The light fixture  400  can include an upper gasket  410 . The gasket  410  can provide a seal between a surface to which the lighting fixture  400  is mounted and the fixture housing  420  so that dust, moisture, bugs, water, and/or other elements are prevented from entering the interior of the fixture housing  402 . In this way, internal components (e.g., circuit board  414 ) can be protected from damage from external sources. The gasket  410  can be positioned in a recessed rim or channel formed in an upper portion of the housing  402  as best shown in  FIG.  11   . 
     The circuit board  414  can be mounted on the backing member  420 , with the backing member  420  connected to the housing  402 , for example, using one or more fasteners. The backing member  420  can act as a heat sink that is configured to transfer heat away from the circuit board  414 . In such cases, the backing member  420  can include any suitable heat conducting material, such as a metal material. In some embodiments, the backing member  420  can be integrally formed with the circuit board  414 . The circuit board  414  can be associated with a light engine that includes all of the necessary electronic components for powering the one or more light emitters  416  located on the circuit board  414 . The circuit board  414  can include any combination of components discussed herein. For example, the electronic components can include a driver circuit, a dimmer circuit, and a filter circuit. 
     As discussed above, in order to prevent unsafe overheating, a temperature sensor  422  can be connected to the circuit board  414 , and the circuit board  414  can be configured to reduce the output of the light emitters  416  if the sensor detects that one or more components of the lighting fixture approaches or reaches a maximum temperature. The sensor can monitor an external temperature of the lighting fixture  400  (e.g., the housing  402  or the lens  408 ), an internal temperature (e.g., the circuit board  414 ), or any combination thereof. 
     In the illustrated embodiment, the temperature sensor  422  includes a bi-metal temperature sensor. The bi-metal temperature sensor can act as a switch that is close up to a certain temperature, and then opens once a temperature threshold is crossed, resulting in a reduced power supply to the light emitters  416 . The temperature sensor  422  can be connected to the circuit board  414  and configured to monitor the temperature of the circuit board  414 . Control circuitry associated with the circuit board  414  can be configured to adjust the output of the light emitters  416  in response to an output signal from the temperature sensor  422  as discussed herein. 
     In some embodiments, the reflector  412  can be positioned between the housing  402  and the circuit board  414  and the backing member  420 . The configuration of the reflector  412  can be dependent on the configuration of the housing  402  and the light emitters  416 . In the illustrated embodiment, as best shown in  FIGS.  12  and  13   , the reflector  412  includes a central portion  424  having a substantially conical configuration with a central opening  426 . The central opening  426  is configured to be positioned around the light emitters  416 , with an edge defining the central opening  426  in direct engagement with, or adjacent the circuit board  414 . The central portion  424  extends at an oblique angle away the circuit board  414  from the central opening  426  to an outer rim. 
     One or more ribs  428  extend from the central portion  424  toward the circuit board  414  and backing member  420 . The ribs  428  can provide support for spacing the reflector  412  from the circuit board  414  and backing member  420 . The ribs  428  can also act as heat fins to help transfer heat from the circuit board  414  to the housing  402  for dissipation to an external environment. One or more outer flanges  430  also extend from the central portion  424  toward the circuit board  414  and backing member  420 . The outer flanges  430  can form an enclosure for electrical components positioned on the circuit board  414 . 
     In certain embodiments, a sensor housing  432  can be provided on the reflector to receive the temperature sensor  422 . The sensor housing  432  can extend from an outer surface of the central portion  424  toward the circuit board  414 . A slot adjacent the sensor housing  432  can provide communication between the sensor housing  432  and the circuit board  414 . The temperature sensor  422  can be connected to the circuit board  414  and extend through the slot to be positioned in the sensor housing  432 . In this way, a body of the temperature sensor  422  can be separated from the circuit board  414  by the reflector  412 . 
       FIG.  15    depicts an example circuit board layout for circuit board  414  according to example embodiments of the present disclosure. As shown, the circuit board  414  includes a plurality of light emitters  416  (e.g. LED devices). The light emitters  416  are arranged as a circular array in a first portion  434  of the circuit board  414 . The circuit board  414  also includes electronic components  418  for providing and conditioning power to the plurality of light emitters  416 . For instance, the circuit board  414  can include electronic components associated with a driver circuit and one or more filter circuits (e.g., including one or more capacitors). The filter circuit(s) can be associated with, for instance, a flicker reducing circuit for reducing flicker in the light output of the LED devices. In some embodiments, the light emitters  416  can correspond to the shape of the housing, for example a rectangular light emitters  416  can be used with a rectangular lighting fixture. 
     As shown in  FIG.  15   , the electronic components  518  associated with driver circuit and flicker reducing circuit can be located in a second portion  436  of the circuit board  414 . The second portion  436  of the circuit board  414  can be disposed in a separate location of the circuit board  414  relative to the first portion  434  of the circuit board  414  such that none of the electronic components associated with the driver circuit or the flicker reducing circuit are located in the first portion  434  of the circuit board  414 . In the example of  FIG.  15   , the first portion  434  of the circuit board  414  can be located in a center portion of the circuit board  414 . The second portion  436  can be located in a peripheral portion of the circuit board  414 . 
       FIGS.  16  and  17    show portions of another exemplary embodiment of a light fixture  500 . The light fixture  500  can have substantially the same configuration as the light fixture  400  shown in  FIGS.  8 - 15   . The light fixture  500  includes a circuit board  514  having a plurality of light emitters  516  and electrical control components  518  connected to a backing member  520 . The light emitters  516  are positioned in a first portion  534  of the circuit board  514  and the control components  518  are positioned in a second portion  536  of the circuit board  514  space from the first portion  534 . 
     The light fixture  500  incorporates a thermistor temperature sensor associated with the circuit board  514 . For example, a negative temperature coefficient (NTC) thermistor can be used. As shown in the schematic of  FIG.  17   , the NTC thermistor can be incorporated into the control circuit on the low voltage side of the light emitters (e.g., LEDs) and provide feedback to the main driver circuit based on a sensed temperature. The feedback can signal the driver to reduce or cutoff power to the light emitters  516  as disused herein. In some embodiments, the NTC thermistor is positioned in the first portion  534  of the circuit board  515 .  FIG.  17    shows a schematic of the driver circuit, LED array, and NTC thermistor only. Those of ordinary skill viewing this disclosure will understand that other electrical components can be incorporated into the system to provide desired functionality and light output. 
     In some embodiments, the NTC thermistor is incorporated into the circuit board at a substantially center region of the light emitters  516 . For example, when the light emitters  516  are arranged in a circular array as shown in  FIG.  15   , the NTC thermistor can be positioned near a center point of the circle. In other configurations, the NTC thermistor can be positioned in region defined by the center of t length or width dimension of the light emitter array  516 . 
     The foregoing detailed description of the certain exemplary embodiments has been provided for the purpose of explaining the general principles and practical application, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with various modifications as are suited to the particular use contemplated. This description is not necessarily intended to be exhaustive or to limit the disclosure to the exemplary embodiments disclosed. Any of the embodiments and/or elements disclosed herein may be combined with one another to form various additional embodiments not specifically disclosed. Accordingly, additional embodiments are possible and are intended to be encompassed within this specification and the scope of the appended claims. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. 
     As used in this application, the terms “front,” “rear,” “upper,” “lower,” “upwardly,” “downwardly,” and other orientational descriptors are intended to facilitate the description of the exemplary embodiments of the present disclosure, and are not intended to limit the structure of the exemplary embodiments of the present disclosure to any particular position or orientation. Terms of degree, such as “substantially” or “approximately” are understood by those of ordinary skill to refer to reasonable ranges outside of the given value, for example, general tolerances associated with manufacturing, assembly, and use of the described embodiments.