Abstract:
A method for dispensing powder includes: providing a device for dispensing powder, the device including a framework, warps connected to the framework, a trough for receiving powder, an actuating member for displacing at least one of the framework and the trough, and an action source for the powder to be detached from the warps and dispensed on an object; supplying the powder to the warps and generating an electric field for the powder to carry an electric charge and become charged powder; and providing a force, by the action source, to at least one of the framework and the warps for the charged powder to be detached from the warps, the charged powder moving dependent on the electric field and being dispensed on the object. The warps have equal amounts of charged powder carried thereon, allowing the charged powder to be distributed evenly.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to a method for forming a uniform powder layer on a workpiece, and, more particularly, to a method and device for dispensing powder. 
         [0003]    2. Description of Related Art 
         [0004]    In the process of manufacturing conventional light emitting diodes (LEDs), phosphors may be dispensed or sprayed thereon. In general coating methods, it is difficult to control the amount of phosphors coated on each area of the object to be coated. As a result, the amount of the phosphor coated in each area is inconsistent, resulting in different thicknesses of the phosphor. 
         [0005]    A conventional spraying system is shown in  FIG. 1 . A supplying device  1  includes a fluidizing plate  10  with a plurality of pores (not shown), a supply unit  11  provided below the fluidizing plate, and a carrier  12 . The fluidizing plate  10  carries powder  8 . 
         [0006]    In use, the carrier  12  is arranged at the top of the fluidizing plate  10 , the supply unit  11  supplies air from the side in order to provide the wind force A through the bottom of the fluidizing plate  10 , and the wind force A brings the powder  8  upwards to the carrier  12  through the pores, such that the powder  8  is attached to the carrier  12 . 
         [0007]    However, in the conventional spraying method, the wind force A moves the powder  8  directly. Also, the wind force A blows towards the entire bottom surface of the fluidizing plate  10 . However, the direction of the air flow cannot be controlled after the air passes through the pores. The direction of the wind force A after it passes through the fluidizing plate  10  is not fixed, causing turbulence. As a result, the powder  8  can neither rise uniformly and be distributed evenly on the carrier  12 , nor be evenly attached to various objects  13 . Therefore, the uniformity requirement for the powder  8  cannot be met. 
         [0008]    Further, since the size of the pores on the fluidizing plate  10  is very small, the powder  8  tends to clog up these pores, and the wind force A is unable to pass through some areas of the fluidizing plate  10 , which results in the unevenness of the powder  8  that are attached to the carrier  12 . Therefore, the uniformity requirement for the powder  8  cannot be met. 
         [0009]    Therefore, there is a need for a solution that addresses the aforementioned issues in the prior art. 
       SUMMARY 
       [0010]    In view of the aforementioned shortcomings of the prior art, the present disclosure provides a device for dispensing powder, which may include: a framework; a plurality of warps each having two ends combined with the framework for the warps to be positioned within the boundary of the framework; a trough for receiving powder; an actuating member for displacing at least one of the framework and the trough, allowing the warps to be positioned inside the trough and loaded with the powder inside the trough; and an action source for the powder to be detached from the warps and then dispensed on an object to be coated. 
         [0011]    In an embodiment, the device may further include a carrier for carrying the object to be coated, and the carrier is positioned above the framework and separated from the framework. 
         [0012]    In an embodiment, the action source acts on at least one of the framework and the warps to vibrate the powder for the powder to be detached from the warps and dispensed on the object to be coated. In an embodiment, the action source may include impact force conduction, fluid power, sound wave or ultrasound. 
         [0013]    The present disclosure further includes a method for dispensing powder, which may include: providing the aforementioned device; supplying the powder to the warps; generating an electric field for the powder to carry an electric charge and thus become charged powder; and providing a force, by the action source, to at least one of the framework and the warps for the charged powder to be detached from the warps, wherein the charged powder moves dependent on the electric field for the charged powder to be dispensed on the object to be coated. 
         [0014]    In an embodiment, the device further includes a carrier for carrying the object to be coated, and the carrier is positioned on top of the framework and separated from the framework. 
         [0015]    In an embodiment, the step of supplying the powder to the warps may include displacing, by the actuating member, at least one of the framework and the trough for the warps to be positioned in the trough and loaded with the powder in the trough; and move, by the actuating member, the warps out of the trough. 
         [0016]    With the actuating member and the warps (lines) according to the present disclosure, when the device is in use, the powder is attached to the warps, and the amounts of powder on each place of the warps are substantially the same, and a force is further applied to at least one of the framework and the warps, such that the quantities of charged powder being moved on each place of the warps are substantially the same, thereby avoiding the problem that powder cannot be uniformly coated on each LED in the prior art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The present disclosure can be more fully understood by reading the following detailed description of the preferred embodiments, with reference made to the accompanying drawings, wherein: 
           [0018]      FIG. 1  is a cross-sectional diagram illustrating a conventional powder coating device using air stream; 
           [0019]      FIGS. 2 to 2 ″ are schematic diagrams illustrating a device for dispensing powder in accordance with the present disclosure in different states; and 
           [0020]      FIGS. 3A to 3D  are top-view diagrams illustrating different implementations of the distribution of a plurality of warps. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0021]    The present disclosure is described by the following specific embodiments. Those with ordinary skills in the arts can readily understand other advantages and functions of the present disclosure after reading the disclosure of this specification. The present disclosure may also be practiced or applied with other different implementations. Based on different contexts and applications, the various details in this specification can be modified and changed without departing from the spirit of the present disclosure. 
         [0022]    It should be noted that the structures, ratios, sizes shown in the drawings appended to this specification are to be construed in conjunction with the disclosure of this specification in order to facilitate understanding of those skilled in the art. They are not meant, in any ways, to limit the implementations of the present disclosure, and therefore have no substantial technical meaning. Without affecting the effects created and objectives achieved by the present disclosure, any modifications, changes or adjustments to the structures, ratio relationships or sizes, are to be construed as fall within the range covered by the technical contents disclosed herein. Meanwhile, terms, such as “up”, “down”, “bottom”, “first”, “second”, “a” and the like, are for illustrative purposes only, and are not meant to limit the range implementable by the present disclosure. Any changes or adjustments made to their relative relationships, without modifying the substantial technical contents, are also to be construed as within the range implementable by the present disclosure. 
         [0023]      FIGS. 2 to 2 ″ are schematic diagrams illustrating a device for dispensing powder  2  in accordance with the present disclosure in different states.  FIGS. 3A to 3D  are diagrams illustrating different implementations of a plurality of warps loaded with powder. 
         [0024]    As shown in  FIG. 2 , the device for dispensing powder  2  includes: a framework  20 , a trough  21 , an actuating member  24  and an action source  25 . In an embodiment, the device for dispensing powder  2  further includes lines, such as a plurality of warps and woofs, as shown in  FIGS. 3A to 3D . 
         [0025]    Refer to  FIGS. 3A to 3D  for details on the lines included in the device for dispensing powder  2  according to the present disclosure. As shown in  FIG. 3A , both ends of each of the warps  30   a  are adhered or wound onto the framework  20 . Each warp  30   a  is within the boundary of the framework  20 . 
         [0026]    As shown in  FIG. 3B , the warps  30   a  are distributed horizontally. It is noted that the terms “warps” and “woofs” used herein are only for describing groups of lines that are distributed in certain ways, for example, extending in the same direction within a group. Preferably, the warps  30   a  are evenly distributed. 
         [0027]    As shown in  FIGS. 3C and 3D , the device for dispensing powder further includes a plurality of woofs  30   b.  Both ends of each of the woofs  30   b  are combined with the framework  20 , such that the warps  30   b  are within the boundary of the framework  20 . The woofs  30   b  and the warps  30   a  form a mesh structure  30 . In an embodiment, the warps  30   a  and the woofs  30   b  shown in  FIG. 3D  are distributed non-vertically and non-horizontally. Similarly, it is noted that the terms “warps” and “woofs” used herein are only for describing groups of lines that are distributed in certain ways, for example, extending in the same direction within a group. Preferably, the warps  30   a  and woofs  30   b  are evenly distributed. Moreover, in an embodiment the lines shown in  FIG. 3A to 3D  are substantially provided on the same plane. 
         [0028]    Referring back to  FIG. 2 , the trough  21  is used for loading powder  9 . The powder  9  may include a plurality of powder particles  90  and adhesive  91 . In an embodiment, the adhesive  91  may include solid particles. The adhesive  91  may be adhered to or separated from the powder particles  90 . In an embodiment, the adhesive  91  may cover the powder particles  90 . The powder particles  90  may be, for example, phosphor, nano tubes, quantum dots, carbon tubes, graphene. However, the powder  9  may also include just the powder particles  90 , without the adhesive  91 . 
         [0029]    The device for dispensing powder  2  may further include a carrier  22  provided above the framework  20  and is spaced apart from the framework  20 . The carrier  22  can be used for receiving charged powder  9 ′ shown in  FIG. 2 ″, such that a plurality of objects  23  (e.g., LEDs) to be coated can be carried on the carrier  22 , and the charged powder  9 ′ can be formed on the objects  23 . 
         [0030]    In an embodiment, the actuating member  24  can be used for displacing the framework  20 . During implementation, the actuating member  24  can be mechanically fastened to the framework  20 , including, but not limited to, screwing, such that the framework  20  is displaced by moving the actuating member  24 . Alternatively, the actuating member  24  may actuate the framework  20  via a movable part such as a connecting rod. 
         [0031]    As shown in  FIG. 2 ′, when the device for dispensing powder  2  is in use, first the actuating member  24  displaces the framework  20 , then the warps  30   a  move into the powder  9  in the trough  21 , and the powder  9  is attached to the warps  30   a.  Then, the actuating member  24  moves the framework  20  out of the trough  21 , as shown in  FIG. 2 ″. Alternatively, the actuating member  24  may move the trough  21  instead, such that the framework  20  is in the trough  21  or out of the trough  21 . 
         [0032]    Moreover, the device for dispensing powder  2  further includes an action source  25  that can be provided in the framework  20  (not shown), or adjacent to the framework  20 , such as above or at the left or right hand side of the framework  20 , or at the bottom of the framework  20  as shown in  FIG. 2 . The action source  25  acts on at least one of the framework  20  and the warps  30   a  so as to vibrate the powder  9  in such a way that it leaves the warps  30   a.  Alternatively, in an embodiment that includes woofs  30   b,  the powder  9  leaves the woofs  30   b.  Furthermore, the action source  25  is close to the periphery of the framework  20 . Specifically, the action source  25  may include, but not limited to, ultrasound, impact force, bumps, jets of water or a device with a hook member that perturbs the lines, that is, the warps  30   a  and/or the woofs  30   b.    
         [0033]    Therefore, in the schematic diagram illustrating a particular operating state in  FIG. 2 ″, the action source  25  is turned on to provide a force to at least one of the framework  20  and the warps  30   a,  causing the warps  30   a  to vibrate, which in turn, vibrate the charged powder  9 ′ on the warps  30   a,  such that the charged powder  9 ′ moves away from the warps  30   a.  The charged powder  9 ′ rises towards the carrier  22  as a result of the electric field. Then, the charged powder particles  90  are attached to the objects  23  to be coated through the adhesive  91 . Specifically, the method for charging the powder  9  may include, after the warps  30   a  are moved out of the trough  21 , generating an electric field between the framework  20  and the carrier  22  using a power supply, such that the powder  9  becomes charged powder  9 ′. For example, the warps  30   a  are supplied with a negative high voltage to create an electric field, and corona discharge is created by the evenly distributed plurality of warps  30   a,  such that the powder  9  carries electrons (i.e., negatively charged) and becomes the charged powder  9 ′. As a result of the electric field, the charged powder  9 ′ becomes more readily attached to the objects  23  to be coated. In another embodiment, the warps  30   a  may also carry holes (i.e., positively charged). 
         [0034]    Therefore, once the charged powder  9 ′ is moved away from the warps  30   a  as a result of the force applied by the action source  25 , the charged powder  9 ′ is immediately led towards the objects  23  to be coated by the electric field, and the upward force (i.e., electric field attraction) from the warps  30   a  to the carrier  22  is enhanced. There is no other external forces (e.g., the traditional wind force) between the warps  30   a  to the carrier  22 , such that the direction (i.e., upwards direction) of the charged powder  9 ′ can be effectively controlled. This ensures the uniformity of the powder particles  90  attached on the objects  23  to be coated. 
         [0035]    After one electrostatic adsorption coating is carried out, the majority of the powder  9  on the warps  30   a  is removed, and the warps  30   a  return to the state before the powder  9  is attached as shown in  FIG. 2 . If electrostatic adsorption is to be performed again, as described above, the framework  20  and the trough  21  are moved relative to each other by the actuating member  24 , such that powder  9  is attached onto the warps  30   a,  and then the warps  30   a  with powder  9  attached thereon are separated from the trough  21 . 
         [0036]    With the actuating member and the warps (lines) according to the present disclosure, when the device is in use the powder is attached to the warps, the quantities of powder on each place of the warps are substantially the same, and a force is further applied to at least one of the framework and the warps, such that that the quantities of charged powder being moved on each place of the warps are substantially the same, thereby avoiding the problem that powder cannot be uniformly coated on each LED in the prior art. 
         [0037]    Therefore, compared to the prior art, during mass production, the device for dispensing powder according to the present disclosure is able to uniformly distribute charged powder on each object to be coated, regardless of how large the ranges of actuation the lines are, thereby ensuring the uniformity of powder in each batch of products. 
         [0038]    The above embodiments are only used to illustrate the principles of the present disclosure, and should not be construed as to limit the present disclosure in any way. The above embodiments can be modified by those with ordinary skill in the art without departing from the scope of the present disclosure as defined in the following appended claims.