Patent Publication Number: US-2021195743-A1

Title: Multilayer construction for mounting light emitting devices

Description:
TECHNICAL FIELD 
     This disclosure relates generally to constructions upon which light emitting devices can be mounted, and to systems and methods related to such constructions. 
     BACKGROUND 
     Light emitting devices (LEDs) and/or other devices can be mounted on a substrate cut or formed into single or multi-device units. Electrically conductive pads disposed on the substrate are electrically connected to terminals of the LED. 
     BRIEF SUMMARY 
     A flexible multilayer construction for mounting a light emitting semiconductor device (LESD) includes a flexible dielectric substrate comprising opposing top and bottom major surfaces and an LESD mounting region on the top major surface. Electrically conductive spaced apart first and second pads are disposed in the LESD mounting region for electrically connecting to corresponding electrically conductive first and second terminals of an LESD received in the LESD mounting region. The first and second pads define a groove therebetween having a maximum width less than about 250 microns and a maximum depth d. An electrically insulative reflective material at least partially fills the groove to a maximum thickness greater than about 0.7d and less than about 1.2d and a maximum width less than about 270 microns. 
     Some embodiments involve a flexible multilayer system for being divided into a plurality of flexible multilayer constructions. Each flexible multilayer construction is configured for mounting a different light emitting semiconductor device. The flexible multilayer system includes a flexible dielectric substrate comprising opposing top and bottom major surfaces. An electrically conductive layer is formed on the top major surface of dielectric substrate. The conductive layer defines one or more spaced apart parallel wider first grooves extending lengthwise along a first direction and one or more spaced apart parallel narrower second grooves extending lengthwise along an orthogonal second direction. Each narrower second groove fluidically communicates with at least one wider first groove. Each first and second groove is at least partially filled with an electrically insulative reflective material. 
     Some embodiments are directed to a flexible multilayer system for being divided into a plurality of flexible multilayer constructions. Each flexible multilayer construction is configured for mounting a different light emitting semiconductor device. The flexible multilayer system includes a plurality of spaced apart parallel first grooves extending lengthwise along a first direction and a plurality of spaced apart parallel second grooves extending lengthwise along a different second direction. Each second groove is narrower than each first groove and communicates with at least one first groove. Each first and second groove is at least partially filled with an electrically insulative reflective material. 
     According to some embodiments, a flexible multilayer system includes a flexible dielectric substrate comprising opposing top and bottom major surfaces. A patterned electrically conductive layer is disposed on the top surface and defines a plurality of spaced apart capillary grooves. Each capillary groove has a width, w, and a depth, d. An electrically insulative reflective material is disposed within the plurality of capillary grooves. A plurality of reservoir regions is defined by the patterned electrically conductive layer. Each reservoir region is fluidically coupled to one or more of the capillary grooves. Each reservoir region is configured to hold an amount of the electrically insulative reflective material to at least partially fill the one or more capillary grooves to which it is fluidically coupled such that a maximum thickness of the reflective material in the one or more capillary grooves is greater than about 0.7d and less than about 1.2d and a maximum width of the reflective material in the one or more capillary grooves is less than about 1.1w. The width and depth of each capillary groove provides capillary movement of the electrically insulative reflective material within the capillary groove. 
     Some embodiments involve a flexible multilayer construction for mounting an electronic device. The flexible multilayer construction includes electrically conductive spaced apart first and second pads for electrically connecting to corresponding electrically conductive first and second terminals of an electronic device. The first and second pads define a capillary groove therebetween that is at least partially filled with an electrically insulative reflective material by a capillary action. 
     Some embodiments are directed to a method of fabricating one or more multilayer construction for mounting one or more light emitting semiconductor devices. A patterned electrically conductive layer is formed on a top major surface of a dielectric substrate. The patterned conductive layer defines a wider first groove and a narrower second groove communicating with the wider first groove. A solution of an electrically insulative reflective material is deposited in the wider first groove. The narrower second groove is sufficiently narrow to provide a capillary action so that the solution of the reflective material deposited in the wider first groove flows into the narrower second groove by capillary action and at least partially fills the narrower second groove. 
     These and other aspects of the present application will be apparent from the detailed description below. In no event, however, should the above summaries be construed as limitations on the claimed subject matter, which subject matter is defined solely by the attached claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  provides a cross sectional view of a flexible multilayer construction for mounting an electronic device such as an light emitting semiconductor device (LESD) in accordance with some embodiments; 
         FIG. 1B  shows the same multilayer construction as in  FIG. 1A  with an LESD mounted to the multilayer construction; 
         FIG. 1C  shows a top view of a multilayer construction in accordance with some embodiments; 
         FIGS. 2A and 2B  illustrate a multilayer system that can be divided into a plurality of multilayer constructions for mounting a single LESD in accordance with some embodiments; 
         FIG. 2C  depicts a multilayer construction that results from dividing the multilayer system of  FIGS. 2A and 2B ; 
         FIGS. 3A and 3B  illustrate a multilayer system that can be divided into a plurality of multilayer constructions for mounting multiple LESDs in accordance with some embodiments; 
         FIG. 3C  depicts a multilayer construction that results from dividing the multilayer system of  FIGS. 3A and 3B ; and 
         FIG. 4  is a flow diagram illustrating a method fabricating a multilayer construction for mounting one or more LESDs in accordance with some embodiments. 
     
    
    
     The figures are not necessarily to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number. 
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Embodiments disclosed herein relate to constructions for mounting light emitting semiconductor devices (LESDs). In constructions configured to mount LESDs, the supporting substrate may absorb the light emitted from LESD chip. Additionally, where the LESD emits ultraviolet (UV), the UV light emitted from LESD may tend to degrade the substrate over the time, especially for LESDs that emit high intensity light. The absorption of light and/or degradation of the substrate material can be reduced by coating portions of the substrate surface with an absorption-reducing coating while leaving the electrically conductive pads substantially clear for attaching the LESDs. However, when the electrically conductive pads are closely spaced standard coating processes, such as silk screening, are suboptimal because the desired deposition resolution cannot be achieved. Embodiments disclosed herein involve approaches for applying a reflective material between the electrically conductive pads by capillary movement. 
       FIG. 1A  provides a cross sectional view of a flexible multilayer construction  100  for mounting an electronic device such as an LESD.  FIG. 1B  shows the same multilayer construction  100  as in  FIG. 1A  with an LESD  119  mounted to construction  100 . The construction  100  includes a flexible substrate  110  that includes dielectric portions  116 , e.g., comprising polyimide film (PI) and may include electrically conductive portions  115 , e.g., comprising copper. The flexible substrate  110  has opposing top  110   b  and bottom  110   a  major surfaces and one or more LESD mounting regions  110   c  on the top major surface  110   b . Electrically conductive spaced apart first  121  and second  122  pads are disposed in the LESD mounting region  110   c  and are configured for electrically connecting to corresponding electrically conductive first and second terminals  141 ,  142  of an LESD  119  (see  FIG. 1B ). Adjacent first and second pads  121 ,  122  define a capillary groove  135  therebetween having a maximum width, w, and a maximum depth, d. The groove  135  is configured such that it can be at least partially filled with an electrically insulative reflective material  130  by a capillary action. 
     As shown in  FIGS. 1A and 1B , in some embodiments, the pads  121 ,  122  may include fiducials  150  that facilitate positioning the LESDs  119 . 
     In various embodiments, the maximum width of the groove  135  may be less than about 250 microns, less than about 200 microns, less than about 150 microns, less than about 100 microns, less than about 80 microns, less than about 60 microns, or even less than about 40 microns. The depth, d, of the groove may be in a range from about 10 microns to 80 microns or in a range from about 10 microns to 70 microns, for example. In some embodiments the maximum width of the filled reflective material  130  is less than about 260 microns. The maximum width of the filled reflective material  130  may be less than about 1.1w which means that the reflective material  130  may be disposed in the groove  135  and extending slightly onto the top surface of one or both electrically conductive pads  121 ,  122  on either side of the groove  135 . In some scenarios, when the reflective material  130  is at least partially filling the groove  135 , some of the reflective material  130  is disposed on a top surface of either the first and/or second pad. The placement of the reflective material  130  on the top surface of one or both electrically conductive pads  121 ,  122  is limited to within 30 microns, within 20 microns, or even within 15 microns of the groove  135 . 
     The flexible multilayer construction  100  may have an average optical transmittance of less than about 25%, or less than about 20% in a visible range of the spectrum at a location on the filled reflective material  130  inside lateral edges  136 ,  137  of the groove  135 . The flexible multilayer construction  100  may have an average optical reflectance of greater than about 70%, or greater than about 80% in a visible range of the spectrum at a location on the filled reflective material  130  inside lateral edges  136 ,  137  of the groove  135 . 
     The filled reflective material  130  may increase, by at least 60%, or at least 70% an average optical transmittance of the flexible multilayer construction  100  at a location inside lateral edges  136 ,  137  of the groove  135 . The top surface  131  of the reflective material  130  may be flat, or may be concave toward the bottom surface  138  of the groove  135 , or may be convex away from a bottom surface  138  of the groove  135 . 
     As discussed in more detail herein, in some embodiments, each capillary groove  135  may be fluidically connected to one or more reservoir regions which can be loaded with the reflective material. The reflective material deposited in the reservoir regions moves along the capillary groove by capillary forces. The reservoir regions are wider than the width, w, of the groove. For example the width of the capillary groove  135  may be at least about 70% less than the width of the reservoir regions. 
       FIG. 1C  shows a top view of a multilayer construction  160  in accordance with some embodiments. Each capillary groove  175  extends between opposing first and second groove ends  161 ,  162  and is intersected by one or more reservoir regions  163 . A width of the groove  175  at at least one of the first and second groove ends  161 ,  162  may be at least about 70% less than a width of the groove  135  at one or more points  163  between the first and second groove ends  161 ,  162 . The wider points  163  along the grooves  175  are reservoir regions. Although multiple reservoir regions are shown in  FIG. 1C , in some embodiments, only one reservoir region intersects a groove, e.g., at the midpoint of the groove between the first and second groove ends. 
     As illustrated in the top views of  FIGS. 2A through 2C and 3A through 3C , a flexible multilayer system  200 ,  300  may be configured to be divided into a plurality of flexible multilayer constructions  290 ,  390 . Each flexible multilayer construction  290 ,  390  is configured for mounting one or more different devices, e.g., one or more LESDs. A single device can be mounted on the flexible multilayer construction  290  shown in  FIG. 2C . Multiple devices can be mounted on the flexible multilayer construction  390  shown in  FIG. 3C . 
     According to some embodiments, the flexible multilayer system  200 ,  300  includes a flexible dielectric substrate comprising opposing top and bottom major surfaces (see  FIG. 1A , elements  110 ,  110   b ,  110   a ). A patterned electrically conductive layer  220  is disposed on the top surface of the flexible dielectric substrate and defines a plurality of spaced apart capillary grooves  240 ,  340 , each capillary groove  240 ,  340  having a width, w, and a depth, d. An electrically insulative reflective material  250 ,  350  is disposed within the plurality of capillary grooves  240 ,  340 . The width and depth of each capillary groove  240 ,  340  supports capillary flow of the electrically insulative reflective material  250 ,  350  within the capillary groove  240 ,  340 . One or more reservoir regions  230 ,  330  are fluidically connected to one or more of the capillary grooves  240 ,  340 . The reservoir regions  230 ,  330  are shown as grooves in  FIGS. 2A through 3C . However, the reservoir regions  230 ,  330  may have any suitable shape so long as the one or more reservoir regions  230 ,  330  are capable of holding an amount of the electrically insulative reflective material  250 ,  350  to at least partially fill the one or more capillary grooves  240 ,  340  to which they are fluidically connected to a maximum thickness of the reflective material greater than about 0.7d and less than about 1.2d and such that the maximum width of the reflective material is less than about 1.1w. 
     Each reservoir region  230 ,  330  has an area that is sufficiently large such that the reservoir region  230 ,  330  can reliably be screen printed with a solution of the reflective material  250 ,  350  without printing the solution beyond a lateral edge  231 ,  232 ,  331 ,  332  of the reservoir region  230 ,  330 . Each capillary groove  240 ,  340  is sufficiently narrow that it cannot reliably be screen printed with a solution of the reflective material  250 ,  350  without printing the solution beyond a lateral edge  241 ,  242 ,  341 ,  342  of the groove  240 ,  340 . For example, a minimum width of each wider first groove  230 ,  330  may be at least 400 microns in some embodiments. A maximum width of each narrower second groove  240 ,  340  may be at most 200 microns in some embodiments. 
     As illustrated in  FIGS. 2A through 3C , the plurality of reservoir regions  230 ,  330  may comprises a plurality of spaced apart parallel wider grooves extending along a first direction (y) and the plurality of capillary grooves  240 ,  340  may comprise a plurality of narrower parallel grooves extending along a second (x) direction that is different from the first direction. In some embodiments, each first and second groove  230 ,  330 ,  240 ,  340  is filled with the reflective material  250 ,  350 . 
     As best understood with reference to the cross sectional view of  FIG. 1A  and the top views of  FIGS. 2A and 3A , the flexible multilayer system  200 ,  300  includes a flexible dielectric substrate  110  comprising opposing top  110   b  and bottom major surfaces  110   b . An electrically conductive layer  220 ,  320  is formed on the top major surface of dielectric substrate  110 . The conductive layer  220 ,  320  defines one or more spaced apart parallel wider first grooves  230 ,  330  extending lengthwise along a first (y) direction. One or more spaced apart parallel narrower second grooves  240 ,  340  extend lengthwise along an orthogonal second (x) direction. Each narrower second groove  240 ,  340  fluidically communicates with at least one wider first groove  230 ,  330 . An electrically insulative reflective material  250 ,  350  at least partially fills each first  230 ,  330  and second  240 ,  340  groove. 
     Each first  230 ,  330  and second groove  240 ,  340  extends depthwise to the top major surface  110   b  of the dielectric substrate  110  (see  FIG. 1A ). For example, in some embodiments the one or more spaced apart parallel wider first grooves  230 ,  330  may comprise at least 20 spaced apart parallel wider first grooves. In some embodiments the one or more spaced apart parallel narrower second grooves  240 ,  340  comprises at least 50 spaced apart parallel narrower second grooves. 
     The flexible multilayer system  200 ,  300  can be divided into a plurality of flexible multilayer constructions  290 ,  390  by cutting along dashed lines  299 ,  399 . Each construction  290 ,  390  comprises an LESD mounting region  291 ,  391  comprising a section of a narrower second groove  240 ,  340 . The construction  290 ,  390  has a first portion  261 ,  361  of the conductive layer  220 ,  320  on a first lateral side of the second groove  240 ,  340  and a second portion  262 ,  362  of the conductive layer  220 ,  320  on an opposite second lateral side of the second groove  240 ,  340 . As shown in  FIG. 2C , in some implementations, the narrower second grooves  240  extend to the edges  292 ,  293  of the flexible multilayer construction  290 . The first  261 ,  361  and second  262 ,  362  conductive portions are electrically isolated from each other and form electrically conductive spaced apart respective first and second pads for electrically connecting to corresponding electrically conductive first and second terminals of an LESD received in the LESD mounting region  291 ,  391 . The reflective material  250 ,  350  at least partially fills the second groove  240 ,  340  and is configured to reflect light emitted by the LESD. 
       FIG. 4  is a flow diagram illustrating a method fabricating a multilayer construction for mounting one or more light emitting semiconductor devices (LESD) in accordance with various embodiments. A patterned electrically conductive layer is formed  410  on a top major surface of substrate comprising a dielectric material. For example, the flexible substrate may comprise one or more of polyimide (Pp, thermoplastic PI, aromatic polyamide, liquid crystal polymer (LCP), polycarbonate (PC), polyether ether ketone, polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polycyclic olefin, polysulfone (PSU), polyethylene naphthalate (PEN), epoxy resin, and thermoplastic dielectric material. 
     The patterned conductive layer defines a reservoir region and a capillary groove fluidically communicating with the reservoir region. Forming the patterned conductive layer may involve one or more of a lithography process, a plating process, a printing process, a coating process, and an etching process. For example, the reservoir region may comprise a wider first groove and the capillary groove may comprise narrower second groove. Each narrower second groove communicates with at least one wider first groove. For example, in some embodiments, each wider first groove extends lengthwise along a first direction and each narrower second groove extends lengthwise along a different second direction. 
     A solution of an electrically insulative reflective material is deposited  420  in the wider first groove, e.g., by screen printing the solution in the wider first groove. The electrically insulative reflective material may comprise one or more of epoxy, polyurethane, polyimide and polysilicon, for example. In some implementations, the solution of the electrically insulative reflective material is substantially solventless or the solution of the electrically insulative reflective material comprises less than about 5% solvent by weight. 
     Each narrower second groove is sufficiently narrow to provide a capillary movement of the solution so that the solution of the reflective material deposited in the wider first groove flows into the narrower second groove in communication with the wider first groove by capillary flow and at least partially fills the narrower second groove. 
     In some implementations, the solution of the electrically insulative reflective material may be pre-cured or otherwise pre-processed to achieve a desired viscosity before it is deposited into the wider second groove. For example, the pre-processing may be applied to electrically insulative reflective material until the viscosity of the electrically insulative reflective material is increased to about 600-800 poise or between about 500 and 800 poise. The step of pre-processing the solution increases the viscosity of the solution to a viscosity that allows both silk screening and capillary movement of the solution. In some embodiments, pre-processing the electrically insulative reflective material involves pre-curing the solution by heating the solution to a temperature in a range of about 40 to 60 degrees Celsius, e.g., about 50 degrees Celsius, or for a period of about 2 to 4 hours to increase a viscosity of the solution prior to deposition. 
     Optionally, the temperature of the dielectric substrate may be held at a temperature greater than a room temperature during the deposition of the reflective material into the wider first grooves (reservoir regions) and the capillary flow of the deposited reflective material into the narrower second grooves (capillary grooves). For example, the temperature of the dielectric substrate may be maintained in a range from about 30 to 80 degrees Celsius, in a range from about 40 to 70 degrees Celsius, in a range from about 45 to 70 degrees Celsius, or in a range from about 50 to 70 degrees Celsius during the deposition and/or capillary flow Maintaining the temperature of the dielectric substrate at a temperature greater than the room temperature can increase a speed of the capillary flow of the deposited reflective material into the narrower second grooves by at least a factor of 10, by at least a factor of 50, or even by at least a factor of 100. 
     Optionally, the electrically insulative reflective material may be deposited  430  in the wider first groove at least a second time. The solution deposited the second time further fills the narrower second groove by capillary action. The dielectric substrate may be held at a temperature greater than a room temperature during the second deposition of the reflective material in the wider first groove and the capillary flow of the deposited reflective material into the narrower second groove. Depositing the reflective material a second time increases the thickness of the reflective material in the wider first groove and the narrower second groove. However, the thickness of the reflective material may increase more in the wider first groove and less in the narrower second groove. 
     The reflective material cures  440  after the deposition of the reflective material in the wider first groove and the capillary flow of the deposited reflective material into the narrower second groove. In some implementations, the curing step comprises increasing a temperature of the reflective material to about 130 to about 170 degrees Celsius, or to about 140 to about 170 degrees Celsius and maintaining the increased temperature for about 1 to 3 hours. In some implementations, the curing step comprises exposing the reflective material to UV radiation. 
     The patterned electrically conductive layer having the reflective material disposed in the one or more wider first grooves and the one or more narrower grooves can be divided  450 , e.g., by cutting, into a plurality of single or multiple device multilayer constructions. Each multilayer construction may include a section of at least one narrower second groove that is at least partially filled with the electrically insulative reflective material. In some implementations, the filled section of the narrower second groove extends to at least one of first and second edges of the flexile multilayer construction. In some implementations, the filled section of the narrower second groove extends to both first and second edges of the flexile multilayer construction. 
     Items disclosed herein include: 
     Item 1. A flexible multilayer construction for mounting a light emitting semiconductor device (LESD), comprising: 
     a flexible dielectric substrate comprising opposing top and bottom major surfaces and an LESD mounting region on the top major surface; 
     electrically conductive spaced apart first and second pads disposed in the LESD mounting region for electrically connecting to corresponding electrically conductive first and second terminals of an LESD received in the LESD mounting region, the first and second pads defining a groove therebetween having a maximum width less than about 250 microns and a maximum depth d; and 
     an electrically insulative reflective material at least partially filling the groove to a maximum thickness greater than about 0.7d and less than about 1.2d and a maximum width less than about 270 microns. 
     Item 2. The flexible multilayer construction of item 1, wherein the maximum width of the groove is less than about 200 microns.
 
Item 3. The flexible multilayer construction of item 1, wherein the maximum width of the groove is less than about 150 microns.
 
Item 4. The flexible multilayer construction of item 1, wherein the maximum width of the groove is less than about 100 microns.
 
Item 5. The flexible multilayer construction of item 1, wherein the maximum width of the groove is less than about 80 microns.
 
Item 6. The flexible multilayer construction of item 1, wherein the maximum width of the groove is less than about 60 microns.
 
Item 7. The flexible multilayer construction of item 1, wherein the maximum width of the groove is less than about 40 microns.
 
Item 8. The flexible multilayer construction of item 1, wherein d is in a range from about 10 microns to 80 microns.
 
Item 9. The flexible multilayer construction of item 1, wherein d is in a range from about 10 microns to 70 microns.
 
Item 10. The flexible multilayer construction of item 1, wherein the maximum width of the filled reflective material is less than about 260 microns.
 
Item 11. The flexible multilayer construction of item 1, wherein the maximum width of the groove is w and the maximum width of the filled reflective material is less than about 1.1w.
 
Item 12. The flexible multilayer construction of any of items 1 through 11, wherein if, when the reflective material is at least partially filling the groove, some of the reflective material is placed on a top surface of either the first or second pad, the placement is limited to within 30 microns of the groove.
 
Item 13. The flexible multilayer construction of any of items 1 through 11, wherein if, when the reflective material is at least partially filling the groove, some of the reflective material is placed on a top surface of either the first or second pad, the placement is limited to within 20 microns of the groove.
 
Item 14. The flexible multilayer construction of any of items 1 through 11, wherein if, when the reflective material is at least partially filling the groove, some of the reflective material is placed on a top surface of either the first or second pad, the placement is limited to within 15 microns of the groove.
 
Item 15. The flexible multilayer construction of any of items 1 through 14, wherein the reflective material at least partially fills the groove by capillary action.
 
Item 16. The flexible multilayer construction of any of items 1 through 15 having an average optical transmittance of less than about 25% in a visible range of the spectrum at a location on the filled reflective material inside lateral edges of the groove.
 
Item 17. The flexible multilayer construction of any of items 1 through 15 having an average optical transmittance of less than about 20% in a visible range of the spectrum at a location on the filled reflective material inside lateral edges of the groove.
 
Item 18. The flexible multilayer construction of any of items 1 through 17 having an average optical reflectance of greater than about 70% in a visible range of the spectrum at a location on the filled reflective material inside lateral edges of the groove.
 
Item 19. The flexible multilayer construction of any of items 1 through 17 having an average optical reflectance of greater than about 80% in a visible range of the spectrum at a location on the filled reflective material inside lateral edges of the groove.
 
Item 20. The flexible multilayer construction of any of items 1 through 19, wherein the filled reflective material increases, by at least 60%, an average optical transmittance of the flexible multilayer construction at a location inside lateral edges of the groove.
 
Item 21. The flexible multilayer construction of any of items 1 through 19, wherein the filled reflective material increases, by at least 70%, an average optical transmittance of the flexible multilayer construction at a location inside lateral edges of the groove.
 
Item 22. The flexible multilayer construction of any of items 1 through 21, wherein a top surface of the reflective material is convex away from a bottom surface of the groove.
 
Item 23. The flexible multilayer construction of any of items 1 through 22, wherein the groove extends between opposing first and second groove ends, a width of the groove at at least one of the first and second groove ends being at least about 70% less than a width of the groove at a half-way point between the first and second groove ends.
 
Item 24. A flexible multilayer system for being divided into a plurality of flexible multilayer constructions, each flexible multilayer construction for mounting a different light emitting semiconductor device (LESD), the flexible multilayer system comprising:
 
     a flexible dielectric substrate comprising opposing top and bottom major surfaces; 
     an electrically conductive layer formed on the top major surface of dielectric substrate, the conductive layer defining
         one or more spaced apart parallel wider first grooves extending lengthwise along a first direction; and   one or more spaced apart parallel narrower second grooves extending lengthwise along an orthogonal second direction, each narrower second groove communicating with at least one wider first groove; and       

     an electrically insulative reflective material at least partially filling each first and second groove. 
     Item 25. The flexible multilayer system of item 24, wherein each first and second groove extends depthwise to the top major surface of the dielectric substrate.
 
Item 26. The flexible multilayer system of any of items 24 through 25, wherein the one or more spaced apart parallel wider first grooves comprises at least 20 spaced apart parallel wider first grooves.
 
Item 27. The flexible multilayer system of any of items 24 through 25, wherein the one or more spaced apart parallel narrower second grooves comprises at least 50 spaced apart parallel narrower second grooves.
 
Item 28. The flexible multilayer system of any of items 24 through 27, wherein each wider first groove is sufficiently wide that it can reliably be screen printed with a solution of the reflective material without printing the solution beyond a lateral edge of the first groove.
 
Item 29. The flexible multilayer system of any of items 24 through 28, wherein each narrower second groove is sufficiently narrow that it cannot reliably be screen printed with a solution of the reflective material without printing the solution beyond a lateral edge of the first groove.
 
Item 30. The flexible multilayer system of any of items 24 through 29, wherein a minimum width of each wider first groove is at least 400 microns, and a maximum width of each narrower second groove is at most 200 microns.
 
Item 31. The flexible multilayer system of any of claims  24  through  30 , wherein when the flexible multilayer system is divided into a plurality of flexible multilayer constructions, each construction comprises an LESD mounting region comprising a narrower second groove of the one or more narrower second grooves having a first portion of the conductive layer on a first lateral side of the second groove and a second portion of the conductive layer on an opposite second lateral side of the second groove, the first and second conductive portions electrically isolated from each other and forming electrically conductive spaced apart respective first and second pads for electrically connecting to corresponding electrically conductive first and second terminals of an LESD received in the LESD mounting region, the reflective material at least partially filling the second groove configured to reflect light emitted by LESD.
 
Item 32. The flexible multilayer system of any of claims  24  through  31 , wherein when the flexible multilayer system is divided into a plurality of flexible multilayer constructions, each flexible multilayer construction includes a section of at least one narrower second groove that is at least partially filled with the electrically insulative reflective material, the filled section of the narrower second groove extends to at least one of first and second edges of the flexile multilayer construction.
 
Item 33. The flexible multilayer system of any of items 24 through 31, wherein when the flexible multilayer system is divided into a plurality of flexible multilayer constructions, each flexible multilayer construction includes a section of at least one narrower second groove that is at least partially filled with the electrically insulative reflective material, the filled section of the narrower second groove extends to both of first and second edges of the flexile multilayer construction.
 
Item 34. A flexible multilayer system for being divided into a plurality of flexible multilayer constructions, each flexible multilayer construction for mounting a different light emitting semiconductor device (LESD), the flexible multilayer system comprising a plurality of spaced apart parallel first grooves extending lengthwise along a first direction and a plurality of spaced apart parallel second grooves extending lengthwise along a different second direction, each second groove narrower than each first groove and communicating with at least one first groove, each first and second groove at least partially filled with an electrically insulative reflective material.
 
Item 35. A flexible multilayer system comprising:
 
     a flexible dielectric substrate comprising opposing top and bottom major surfaces; 
     a patterned electrically conductive layer disposed on the top surface and defining a plurality of spaced apart capillary grooves, each capillary groove having a width, w, and a depth, d; 
     an electrically insulative reflective material disposed within the plurality of capillary grooves; and 
     a plurality of reservoir regions defined by the patterned electrically conductive layer, each reservoir region fluidically coupled to one or more of the capillary grooves and configured to hold an amount of the electrically insulative reflective material to at least partially fill the one or more capillary grooves such that a maximum thickness of the reflective material in the one or more capillary grooves is greater than about 0.7d and less than about 1.2d and a maximum width of the reflective material in the one or more capillary grooves is less than about 1.1w, wherein the width and depth of each capillary groove provides capillary movement of the electrically insulative reflective material within the capillary groove. 
     Item 36. The flexible multilayer system of item 35, wherein: 
     each reservoir region has an area that is sufficiently large such that the reservoir region can reliably be screen printed with a solution of the reflective material without printing the solution beyond a lateral edge of the reservoir region; and 
     each capillary groove is sufficiently narrow that it cannot reliably be screen printed with a solution of the reflective material without printing the solution beyond a lateral edge of the groove. 
     Item 37. The flexible multilayer system of any of items 35 through 36, wherein: 
     the plurality of reservoir regions comprises a plurality of spaced apart parallel wider grooves extending along a first direction; and 
     the plurality of capillary grooves comprises a plurality of narrower parallel grooves extending along a second direction that is different from the first direction. 
     Item 38. A flexible multilayer construction for mounting an electronic device and comprising electrically conductive spaced apart first and second pads for electrically connecting to corresponding electrically conductive first and second terminals of an electronic device, the first and second pads defining a capillary groove therebetween at least partially filled with an electrically insulative reflective material by a capillary action.
 
Item 39. The flexible multilayer construction of claim  38 , wherein:
 
     the capillary groove has a maximum width less than about 250 microns and a maximum depth d; and 
     the electrically insulative reflective material fills the capillary groove to a maximum thickness greater than about 0.7d and less than about 1.2d. 
     Item 40. The flexible multilayer construction of any of items 38 through 39, wherein the maximum width of the capillary groove is w and the maximum width of the filled reflective material is less than about 1.1w.
 
Item 41. The flexible multilayer construction of any of items 38 through 40, wherein the electrically conductive spaced apart first and second pads are disposed on a dielectric substrate and the capillary groove extends to at least one edge of the dielectric substrate.
 
Item 42. A method of fabricating one or more multilayer construction for mounting one or more light emitting semiconductor devices (LESD), the method comprising:
 
     providing a flexible dielectric substrate; 
     forming a patterned electrically conductive layer on a top major surface of dielectric substrate, the patterned conductive layer defining:
         a wider first groove; and   a narrower second groove communicating with the wider first groove; and       

     depositing a solution of an electrically insulative reflective material in the wider first groove, the narrower second groove sufficiently narrow to provide a capillary action so that the solution of the reflective material deposited in the wider first groove flows into the narrower second groove by capillary action and at least partially fills the narrower second groove. 
     Item 43. The method of item 42, wherein the flexible substrate comprises one or more of polyimide (PI), thermoplastic PI, aromatic polyamide, liquid crystal polymer (LCP), polycarbonate (PC), polyether ether ketone, polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polycyclic olefin, polysulfone (PSU), polyethylene naphthalate (PEN), epoxy resin, and thermoplastic dielectric material.
 
Item 44. The method of any of items 42 through 43, wherein the step of patterning the conductive layer comprises one or more of a lithography process, a plating process, a printing process, a coating process, and an etching process.
 
Item 45. The method of any of items 42 through 44, wherein the step of depositing the solution of reflective material in the wider first groove comprises screen printing the solution in the wider first groove.
 
Item 46. The method of any of items 42 through 45, wherein the solution of the electrically insulative reflective material is substantially solventless.
 
Item 47. The method of any of items 42 through 45, wherein the solution of the electrically insulative reflective material comprises less than 5% solvent by weight.
 
Item 48. The method of any of items 42 through 47, further comprising the step of pre-curing the solution of the electrically insulative reflective material to increase a viscosity of the solution.
 
Item 49. The method of item 48, wherein the step of pre-curing the solution comprises heating the solution.
 
Item 50. The method of item 49, wherein the step of heating the solution comprises elevating a temperature of the solution to about 40 to 60 degrees Celsius.
 
Item 51. The method of item 49, wherein the step of heating the solution comprises elevating a temperature of the solution to about 50 degrees Celsius.
 
Item 52. The method of item 49, wherein the solution is heated for about 2 to 4 hours.
 
Item 53. The method of any of items 42 through 52, further comprising a step of maintaining a temperature of the dielectric substrate at a temperature greater than a room temperature during the deposition of the reflective material in the wider first groove and the capillary flow of the deposited reflective material into the narrower second groove.
 
Item 54. The method of item 53, wherein the temperature of the dielectric substrate is maintained in a range from about 30 to 80 degrees Celsius.
 
Item 55. The method of item 53, wherein the temperature of the dielectric substrate is maintained in a range from about 40 to 70 degrees Celsius.
 
Item 56. The method of item 53, wherein the temperature of the dielectric substrate is maintained in a range from about 45 to 70 degrees Celsius.
 
Item 57. The method of item 53, wherein the temperature of the dielectric substrate is maintained in a range from about 50 to 70 degrees Celsius.
 
Item 58. The method of item 53, wherein the step of maintaining the temperature of the dielectric substrate at a temperature greater than the room temperature increases a speed of the capillary flow of the deposited reflective material into the narrower second groove by at least a factor of 10.
 
Item 59. The method of item 53, wherein the step of maintaining the temperature of the dielectric substrate at a temperature greater than the room temperature increases a speed of the capillary flow of the deposited reflective material into the narrower second groove by at least a factor of 50.
 
Item 60. The method of item 53, wherein the step of maintaining the temperature of the dielectric substrate at a temperature greater than the room temperature increases a speed of the capillary flow of the deposited reflective material into the narrower second groove by at least a factor of 100.
 
Item 61. The method of any of items 42 through 60, further comprising a step of depositing the solution of the electrically insulative reflective material in the wider first groove a second time, the deposited solution further filling the narrower second groove by capillary action.
 
Item 62. The method of item 61, further comprising maintaining a temperature of the dielectric substrate at a temperature greater than a room temperature during the second deposition of the reflective material in the wider first groove and the capillary flow of the deposited reflective material into the narrower second groove.
 
Item 63. The method of item 61, wherein the step of depositing the reflective material a second time increases a thickness of the reflective material in the wider first groove and the narrower second groove.
 
Item 64. The method of item 63, wherein the thickness of the reflective material increase more in the wider first groove and less in the narrower second groove.
 
Item 65. The method of any of items 42 through 64, further comprising a step of curing the reflective material after the deposition of the reflective material in the wider first groove and the capillary flow of the deposited reflective material into the narrower second groove.
 
Item 66. The method of item 65, wherein the curing step comprises increasing a temperature of the reflective material to about 130 to about 170 degrees Celsius.
 
Item 67. The method of item 66, wherein the increased temperature is maintained for about 1 to 3 hours.
 
Item 68. The method of item 65, wherein the curing step comprises increasing a temperature of the reflective material to about 140 to about 170 degrees Celsius.
 
Item 67. The method of item 65, wherein the curing step comprises exposing the reflective material to UV radiation.
 
Item 68. The method of any of items 42 through 67, wherein the wider first groove extends lengthwise along a first direction, and the narrower second groove extends lengthwise along a different second direction.
 
Item 69. The method of any of items 42 through 68, wherein the patterned conductive layer defines:
 
     a plurality of wider first grooves; and 
     a plurality of narrower second grooves, each narrower second groove communicating with at least one wider first groove. 
     Item 70. The method of item 69, wherein the step of depositing the solution of the electrically insulative reflective material comprises depositing the solution in each wider first groove, the narrower second grooves sufficiently narrow to provide capillary action so that the solution of the reflective material deposited in each wider first groove flows into at least one narrower second groove in communication with the wider first groove by capillary action and at least partially fills the at least one narrower second groove.
 
Item 71. The method of any of items 42 through 70, wherein the electrically insulative reflective material comprises one or more of epoxy, polyurethane, polyimide and polysilicon.
 
Item 72. The method of any of items 42 through 71, further comprising dividing the flexible dielectric substrate having the patterned electrically conductive layer formed thereon into a plurality of the multilayer constructions.
 
     Various modifications and alterations of this invention will be apparent to those skilled in the art and it should be understood that this scope of this disclosure is not limited to the illustrative embodiments set forth herein. For example, the reader should assume that features of one disclosed embodiment can also be applied to all other disclosed embodiments unless otherwise indicated.