Abstract:
A glue dispenser comprises a container accommodating glue, a glue dispensing head and a glue dispensing ring. The glue dispensing head is connected with the container, the glue dispensing head is substantially cylindrical and includes a top surface and a bottom surface opposite to the top surface, the top surface is arranged inside the container, the bottom surface is exposed outside the container, the glue dispensing head has a plurality of through holes extending from the top surface towards the bottom surface to ensure the steady extrusion of glue in small quantities from multiple small outlets arranged in a circle.

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates generally to glue dispensers. 
     2. Description of Related Art 
     Lens modules are widely employed in camera systems and mobile phones for image capturing. A lens module includes a lens barrel, at least one lens group, a spacer, and a filter (e.g., an IR filter). In assembly, the lens group, the spacer and the filter are received in the lens barrel and arranged along an optical axis thereof, and then, a glue dispenser including a needle for dispensing glue is provided. After that, glue is dispensed in drops from the needle between the lens group and the lens barrel to fix the lens group in the barrel, but the needle is small and is easily damaged during the process of dispensing. 
     Therefore, it is desired to provide a glue dispenser and a dispensing method which can overcome the above mentioned problems. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic, isometric view of a glue dispenser according to a first embodiment, the glue dispenser including a glue dispensing head. 
         FIG. 2  is an exploded view of the glue dispenser of  FIG. 1 . 
         FIG. 3  is a schematic, isometric view of the glue dispensing head of  FIG. 1 . 
         FIG. 4  is a schematic, isometric view of a glue dispensing head according to a second embodiment. 
         FIG. 5  is a schematic cross-sectional view showing a method for assembling a lens module by using the glue dispenser of  FIG. 1  according to a third embodiment. 
         FIG. 6  is a cross-sectional view showing a method for assembling a lens module by using the glue dispenser of  FIG. 1  according to a fourth embodiment. 
         FIG. 7  is a cross-sectional view showing a method for assembling a lens module by using the glue dispenser of  FIG. 1  according to a fifth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-2  show a glue dispenser  100  according to a first embodiment. The glue dispenser  100  includes a container  10  accommodating glue, a glue dispensing head  20  and a glue dispensing ring  30 . In the embodiment, the container  10  is substantially a hollow cylinder. The container  20  includes a first end  12  and a second end  14  opposite to the first end  12 . The container  10  further defines a refilling hole  121  at the first end  12  for refilling the container  10  and comprises a sealing member  122  for sealing the refilling hole  121 . 
     Also referring to  FIG. 3 , the glue dispensing head  20  is substantially a cylinder and includes a top surface  22  and a bottom surface  24  opposite to the top surface  22 . The glue dispensing head  20  is connected to the second end  14  of the container  10  via screw threads  23  arranged on the periphery of the glue dispensing head  20  in this embodiment. In this way, the connection between the glue dispensing head  20  and the container  10  is easy to assemble and disassemble. The glue dispensing head  20  can also be connected to the container  10  by crimping or adhesive, or the glue dispensing head  20  can be integrally formed with the container  10 . 
     The top surface  22  is located inside the container  10 . The bottom surface  24  is exposed outside the container  10 . In the illustrated embodiment, the glue dispensing head  20  also includes an annular projection  26  extending from the circumference of the bottom surface  24  away from the top surface  22 . The glue dispensing head  20  also defines a number of through holes  220  along the circumference of the top surface  22 . The through holes  220  extend through the projection  26 , the top surface  22  and the bottom surface  24 . In particular, the through holes  220  are equidistantly distributed along the circumferential surface of the glue dispensing head  20 . 
     The glue dispensing ring  30  is fixed on the annular projection  26  and covers the through holes  220 . The glue dispensing ring  30  is fixed to the annular projection  26  via means such as adhesive bonding. A cross-sectional surface of the glue dispensing ring  30  along a radial direction thereof is square. A cross-section of the glue dispensing ring  30  can also be round or trapezoidal in other embodiments. The glue dispensing ring  30  is made of porous absorbing material such as porous sponge, porous cotton fiber or porous foam plastic. The glue dispensing ring  30  communicates with the container  10  via the through holes  220 , thus the glue from the container  10  can flow along the through holes  220  to the glue dispensing ring  30 , and the glue dispensing ring  30  can adsorb glue by capillary action and can dispense glue when proper pressure is applied to the glue dispensing ring  30 . 
       FIG. 4  shows a glue dispensing head  201  according to a second embodiment. The difference between the glue dispensing head  20  and the glue dispensing head  201  in the second embodiment is that the glue dispensing head  201  omits the annular projection on the bottom surface  241  and the glue dispensing ring  30  is directly arranged on the bottom surface  241 . 
     Referring to  FIGS. 5-7 , a dispensing method using the glue dispenser  100  for assembling a lens module is described below. 
       FIG. 5  shows a dispensing method for assembling a lens module according to a third embodiment, which includes the following steps. 
     Step 1: a lens group  60 , a spacing element  70  and a lens barrel  50  are provided, to result in a pre-glued lens module  80 . The lens group  60  and the spacing element  70  are received in that order in the lens barrel  50  and arranged along an optical axis thereof pre-glue. The pre-glued lens module  80  includes a pre-bonded part  52 . The pre-bonded part  52  is formed by the spacing element  70  and an inner sidewall of the lens barrel  50 . The pre-bonded part  52  receives glue  101  flowing out from the glue dispensing ring  30 . The spacing element  70  is a spacer ring, or a filter. In the embodiment, the spacing element  70  is a spacer ring with an annular protrusion  53  along a circumference thereof, and the pre-bonded part  52  is cooperatively formed by the inner wall of the lens barrel  50  and the annular protrusion  53  and a annular groove is cooperatively defined by the inner wall of the lens barrel  50  and the annular protrusion  53 . The pre-glued lens module  80  is presented for gluing on a rotary carrier  90 . 
     Step 2: a glue dispenser  100  is provided. The container  10  of the glue dispenser  100  contains glue  101 . 
     Step 3: the glue dispenser  100  is moved toward the pre-glued lens module  80  until the glue dispensing ring  30  is positioned in and makes contact with the pre-bonded part  52 . Then the glue dispenser  100  is fixed in place. 
     Step 4: the rotary carrier  90  rotates at a fixed rate with the pre-glued lens module  80 . The glue  101  stored in the glue dispensing ring  30  flows to the pre-bonded part  52  due to pressure applied by the rotation of the pre-glued lens module  80 . Such flow can occur continuously during such rotary movement or can occur at periodic intervals, depending on the gluing pattern desired. 
     Step 5: the glue dispenser  100  is moved away from the pre-bonded part  52  after the dispensing process is completed. The lens group  60  is thus firmly fixed with the lens barrel  50 . 
     The above-described glue dispenser has good dispensing efficiency due to the glue dispensing head  20 ( 201 ) and the glue dispensing ring  30  being used instead of a needle. Contact area of the ring  30  is larger than that of the needle. Therefore, it is more efficient to complete treat one lens module with glue and the ring  30 , compared to the needle, is more immune to incidental damage. 
       FIG. 6  shows a method for assembling the lens module according to a fourth embodiment. The difference between the method shown in the  FIG. 6  and the method shown in  FIG. 5  is that the pre-glued lens module  80  remains stationary while the glue dispenser  100  is rotated at a fixed rate. The glue  101  stored in the glue dispensing ring  30  flows to the pre-bonded part  52  in the same way. 
       FIG. 7  shows a method for assembling the lens module according to a fifth embodiment. The difference between the method shown in  FIG. 5  and the method shown in  FIG. 7  is that the spacer element  701  in  FIG. 7  is a ring-shaped sheet, and the glue dispenser  100  is placed in the pre-bonded part  52  and close to the inner wall of the lens barrel  50 , subsequent steps in the dispensing method are substantially the same as in the third embodiment. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.