Patent Publication Number: US-2013235578-A1

Title: Illumination device and assembling method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part application of and claims the priority benefit of U.S. application Ser. No. 13/410,307, filed on Mar. 2, 2012, now pending, which claims the priority benefits of U.S. provisional application Ser. No. 61/504,328, filed on Jul. 5, 2011 and U.S. provisional application Ser. No. 61/557,352, filed on Nov. 8, 2011. 
     This application is also a co-pending application of U.S. applications with Ser. No. 13/411242, 13/410306, 13/410310, 13/410300, 13/410312, 29/431081. 
     The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
    
    
     TECHNICAL FIELD 
     The technical field relates to an illumination device and an assembling method of the illumination device. 
     BACKGROUND 
     The Light-Emitting Diode (LED) is a semiconductor component. The material for forming the light-emitting chip using the LED mainly includes group III-V chemical compounds, such as gallium phosphide (GaP) or gallium arsenide (GaAs). Using the principle of luminosity of the PN junction, the LED is capable of converting electrical energy into optical energy. The lifespan of an LED is more than a hundred thousand hours, and the LED has fast response, small size, low power consumption, low pollution, high reliability, and is suitable for mass production. 
     With increasing demands for energy conservation and environmental protection, it has become a world trend for people to use LED to construct lighting devices for daily life. In common practice, the LED is installed on a carrier (e.g. a printed circuit board) to become an illumination device. 
     Nevertheless, the LED produces a lot of heat while producing light. Therefore, the heat generated by the LED is often unable to effectively dissipate to the exterior, thus resulting in reduction of device performance. Taking the LED bulb as an example, a heat dissipation structure is disposed on the LED bulb to avoid overheating during LED light emission. If the heat dissipation efficiency of the heat dissipation structure of the LED bulb is poor, the durability of the LED bulb will be degraded. Moreover, because they are limited by the light-emitting characteristics of the LED, the conventional LED bulb is not able to achieve the illumination range of the incandescent bulb. Achieving both illumination range and heat dissipation efficiency, in order to enhance reliability of the LED, has become an important issue. 
     SUMMARY 
     According to one exemplary embodiment, an illumination device comprises a base, a heat dissipation member, at least one flexible printed circuit board (FPC), and a plurality of light-emitting elements. The heat dissipation member has a central axis, a plurality of holding curvy surfaces and a plurality of heat dissipation channels. The holding curvy surfaces and the heat dissipation channels are symmetrically staggered and arranged about a central axis, wherein each of the holding curvy surfaces is radially extended along the central axis. The flexible printed circuit board is disposed on the holding curvy surfaces. The light-emitting elements are disposed on the flexible printed circuit board. 
     According to one exemplary embodiment, an assembling method of an illumination device comprises a base, and a heat dissipation member is assembled to the base. The heat dissipation member has a central axis, a plurality of holding curvy surfaces extending along the central axis, and a plurality of heat dissipation channels. The holding curvy surfaces and the heat dissipation channels are symmetrically staggered and arranged about the central axis. A plurality of light-emitting elements are disposed on at least one flexible printed circuit board. The flexible printed circuit board is assembled onto the heat dissipation member, and the light-emitting elements are located on the corresponding holding curvy surfaces. At least one optical element is assembled to the heat dissipation member for covering the light-emitting elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating an illumination device in accordance with one exemplary embodiment. 
         FIG. 2  is an explosion diagram of the illumination device in  FIG. 1 . 
         FIG. 3  is a partial cross-sectional diagram along the plane P 1  of the illumination device in  FIG. 2 . 
         FIG. 4  is a light distribution diagram of the illumination device in  FIG. 3 . 
         FIG. 5  is a light distribution diagram of a type A 19  conventional incandescent bulb. 
         FIG. 6  is a side view diagram of an illumination device in accordance with one exemplary embodiment. 
         FIG. 7  is the top view diagram along the perspective angle V 1  of the illumination device in  FIG. 1 . 
         FIG. 8  is a top view diagram of an illumination device in accordance with one exemplary embodiment. 
         FIG. 9  is a schematic diagram illustrating an illumination device in accordance with one exemplary embodiment. 
         FIG. 10  is an explosion diagram of the illumination device in  FIG. 9 . 
         FIG. 11  is a schematic diagram illustrating an illumination device in accordance with one exemplary embodiment. 
         FIG. 12  is an explosion diagram of the illumination device in  FIG. 11 . 
         FIG. 13  is a schematic diagram illustrating an illumination device in accordance with one exemplary embodiment. 
         FIG. 14  is an assembly flow-chart of the illumination device in  FIG. 13 . 
         FIG. 15  is a partial schematic diagram illustrating a heat dissipation member inside of the illumination device in  FIG. 13 . 
         FIG. 16˜FIG .  18  are schematic diagrams showing parts of the assemblies of the illumination device in  FIG. 13 . 
         FIG. 19  is a partial cross-sectional diagram illustrating an illumination device in accordance with one exemplary embodiment. 
         FIG. 20  a partial cross-sectional diagram illustrating an illumination device in accordance with one exemplary embodiment. 
         FIG. 21  and  FIG. 22  are partial cross-sectional diagrams illustrating illumination devices in accordance with exemplary embodiments respectively. 
         FIG. 23  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. 
         FIG. 24  is a partial cross-sectional diagram on an orthogonal virtual plane P 5  of the illumination device in  FIG. 23 . 
         FIG. 25  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. 
         FIG. 26  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. 
         FIG. 27  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. 
         FIG. 28  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 1  is a schematic diagram illustrating an illumination device in accordance with one exemplary embodiment.  FIG. 2  is an explosion diagram of the illumination device in  FIG. 1 . Referring to  FIG. 1  and  FIG. 2 , the illumination device  100  is a bulb which comprises a heat dissipation member  110 , a plurality of flexible printed circuit boards (FPSs)  120 , a plurality of light-emitting elements  130 , a base  140 , a circuit board  150 , and an optical element  160 . The heat dissipation member  110  is integrally formed of thermal conductive plastic for instance or is formed of metal with good thermal conductivity, and the heat dissipation member  110  has a central axis C 1 , a plurality of heat dissipation petals  112  and a plurality of heat dissipation channels  114 , wherein the heat dissipation petals  112  and the heat dissipation channels  114  are symmetrically staggered and arranged about the central axis C 1 . 
     Furthermore, each of the heat dissipation petals  112  has a holding curvy surface W 1  and two opposite sidewalls W 2 , W 3  adjoining the holding curvy surface W 1 , wherein each of the holding curvy surfaces W 1  is radially extended along the central axis C 1 . Each of the heat dissipation channels  114  is substantially the space between the two opposite sidewalls W 2 , W 3  of two adjacent heat dissipation petals  112 . The flexible printed circuit board  120  is disposed on the holding curvy surface W 1  of the heat dissipation petal  112  along the surface profile of the heat dissipation member  110 , but the flexible printed circuit board  120  could also bridge over the holding curvy surfaces W 1  of two adjacent heat dissipation petals  112 . The light-emitting element  130 , such as a Light-Emitting Diode packaged on the flexible printed circuit board  120 , is disposed on the flexible printed circuit board  120  by using surface-mount technology (SMT) or COB process (Chip On Board), but the process for disposing the light-emitting element  130  on the flexible printed circuit board  120  is not limited herein. 
     The circuit board  150  assembled between the base  140  and the heat dissipation member  110  is electrically connected to the flexible printed circuit board  120  and the light-emitting element  130  thereon. In addition, the base  140  has a conductive portion  142  that the flexible printed circuit board  120  is electrically connected to, such that the electricity is transported to and lights up the light-emitting elements through the conductive portion  142 , the circuit board  150  and the flexible printed circuit board  120 . Moreover, the optical element  160 , e.g. a cover, is assembled on the heat dissipation member  110  for covering the flexible printed circuit board  120  and the light-emitting element  130  thereon. The optical element  160  has at least one opening  162 , wherein a largest outer diameter R 1  of the heat dissipation member  110  is greater than an inner diameter R 2  of the opening  162 . The opening  162  of the optical element  160  is elastic, and thus is capable of socketing to the heat dissipation member  110 . In the embodiment, the optical element  160  is a protective structure of the flexible printed circuit board  120  and the light-emitting element  130 . Remote phosphor or a diffuser could be added in the raw materials or on the interior wall of the optical element  160  so as to transform the wavelength or enhance the scattering effect of the illumination device  100 . 
     Based on the above, the light-emitting element  130  has the characteristic of the flexible printed circuit board  120 , and may change the light-emitting range and direction with the surface profile of the heat dissipation member  110 . Specifically, the flexible printed circuit board  120  and the light-emitting element  130  are adapted to form a light source with a flexible shape, so as to change the light-emitting direction and range of the light-emitting element  130 , in accordance with the shape profile of the components upon which it depends. Consequently, the illumination device  100  has a wider illumination range and higher heat dissipation efficiency. 
       FIG. 3  is a partial cross-sectional diagram along the plane P 1  of the illumination device in  FIG. 2 , and the central axis C 1  is located on the plane P 1 . Since the heat dissipation petals  112  are symmetrically arranged about the central axis C 1  only one heat dissipation petal  112  is described herein, and the rest of the heat dissipation petals  112  are all equivalent to this description. 
     By the way, a cylindrical coordinate system with a longitudinal axis X 1  and a polar axis X 2  is provided in the disclosure, wherein the central axis C 1  is equal to the longitudinal axis X 1  of the cylindrical coordinate system. The holding curvy surfaces W 1  is radially extended along the central axis C 1  described above means that the holding curvy surfaces W 1  is on a cylindrical surface but with variable radii along the central axis C 1 . 
     Referring to  FIG. 1˜FIG .  3 , an orthogonal projection of the holding curvy surface W 1  of the heat dissipation petal  112  on the plane P 1  is a curve with an inflection point A 1 . In further explanation of the illumination device  100  in  FIG. 1 , the partial holding surface W 1  of the heat dissipation petal  112 , which is covered by the optical element  160 , is substantially a partial spherical surface. Specifically in  FIG. 3 , the curve, which is formed by an orthogonal projection of the holding curvy surface W 1  on the plane P 1 , has an opening angle θ 1  greater than 90 degrees. Consequently, the flexible printed circuit board  120  disposed on the holding curvy surface W 1  is a curvy surface in identical curvature with the holding curvy surface W 1 . 
     In the embodiment, an orthogonal projection of the heat dissipation petal  112  on the central axis C 1  is, for example, a line segment. Two light-emitting elements  130 A,  130 B are located at two opposite ends on the central axis C 1 . The orthogonal projection vectors L 1   a , L 2   a  of the emitted light vectors L 1 , L 2  of the two light-emitting elements  130 A,  130 B on the central axis C 1  are opposite in directions. In light of this, the light-emitting elements  130  could be disposed on the holding curvy surface W 1  between the ranges of the two light-emitting elements  130 A,  130 B. Specifically, the light-emitting elements  130  in  FIG. 3  are adapted to be disposed on the holding curvy surface W 1  across the inflation point A 1  with the deposition of the flexible printed circuit board  120 . Accordingly, the light-emitting elements  130  are disposed along the surface profile of the holding curvy surface W 1  so as to increase the light emitting range of the illumination device  100 , even if the light-emitting angle (the opening angle θ 1 ) of the illumination device  100  is greater than 90 degrees. Specifically, the Light-Emitting Diode, as the light source of the illumination device  100  in the embodiment, overcomes the limit of the light-emitting angle, thus conforms to the illumination range of the conventional incandescent bulb. 
     Referring to  FIG. 3 , the heat dissipation member  110  is divided into a head portion H 1  and a neck portion N 1  according to the appearance, wherein the light-emitting elements  130  are all located on the head portion H 1  of the heat dissipation member  110 , and the minimum outer diameter of the head portion H 1  is substantially greater than the maximum outer diameter of the neck portion N 1 . Specifically, the profile of the neck portion N 1  is not greater than of the head portion H 1 . As a result, this avoids the emitted light from the light-emitting elements  130 B being shielded by the neck portion N 1  due to the neck portion N 1  being too large and reducing the light-emitting efficiency of the illumination device  100 . 
       FIG. 4  is a light distribution diagram of the illumination device in  FIG. 3 .  FIG. 5  is a light distribution diagram of a type A 19  conventional incandescent bulb, wherein the illumination device  100  in  FIG. 4  and the incandescent bulb in  FIG. 5  are both disposed in the same state (such as the state shown in  FIG. 3 ) in order to compare the light-emitting distribution. Referring to  FIG. 3 ,  FIG. 4  and  FIG. 5 , in the illumination device  100  of  FIG. 3 , the light-emitting elements  130  are equidistantly arranged from each other along the holding curvy surface W 1  of the heat dissipation petal  112 , and the light distribution diagram, which is generated by the light-emitting elements  130 , is very similar to the brightness and the range of the type A 19  incandescent bulb. Therefore, the deposition of the light-emitting elements  130  could be further adjusted, so that the illumination device  100  would be able to conform to the light-emitting requirements of the type A 19  incandescent bulb. 
       FIG. 6  is a side view diagram of an illumination device in accordance with one exemplary embodiment. Referring to  FIG. 6 , in the illumination device  200 , the spacing of the orthogonal projections of the light-emitting elements  130  on the central axis C 1  is variable along the central axis C 1 . In other words, the arrangement density of the light-emitting elements  130  is increasing from the optical element  160  towards the base  140 , so as to enhance the brightness towards the base  140  during operation of the illumination device  200 . In order to achieve the specific light distribution curve of the illumination device  200 , the spacing of the orthogonal projections of the light-emitting elements  130  on the central axis C 1  could be increased, decreased, or a combination thereof along the central axis C 1 . Other than changing the arrangement density of the light-emitting elements  130 , the light intensity of the light source could also be changed, such that the light source could be replaced with a higher intensity light-emitting diode along with a denser arrangement when more brightness is required. The arrangement of the light-emitting elements  130  on the flexible printed circuit board  120  and the heat dissipation petal  112  is not limited to the exemplary embodiment, and it is possible to make appropriate adjustment according to the application requirements in order to generate the needed light distribution curve. 
     Similarly, the profile of heat dissipation petals  112  is also not limited to the aforesaid embodiment. The profile of the heat dissipation petals  112 , with the flexible printed circuit board  120 , could be changed according to the requirements of illumination in order to adjust the illumination range of the illumination device  100 . In an alternative embodiment (not shown), the profile of the holding curvy surface of the heat dissipation petal could be a curvy surface with a plurality of inflection points so as to generate a specific brightness and light emitting range. 
     Moreover, the illumination mode of the illumination device  200  could be done via the control circuit (or microprocessor, etc, not shown). In the following, the illumination device  200  in  FIG. 6  is used as an example to depict the driven mode in different regions. 
     The illumination device  200  in  FIG. 6  is divided into disposing regions A, B in up and down manner along the central axis C 1  with independent brightness/darkness and illumination intensities due to the aforesaid control circuit. For example, the light-emitting elements  130  of region A or region B may be controlled to generate a full brightness or complete darkness effect when local light sources in specific directions are needed, and the brightness of the light-emitting elements  130  could also be further controlled. 
     Furthermore, in an alternative embodiment, the light-emitting elements  130  could also be divided into a plurality of regions C according to their deposition on the holding curvy surfaces W 1 , and each of the regions C could be independent or relative to each other. In an embodiment, the light-emitting elements  130 , which are in each region C, could be controlled to emit light individually. In an alternative embodiment, parts of the adjacent holding curvy surfaces W 1 , or holding curvy surfaces W 1  with certain spacing, could be considered as the same region in order to control the light emitted. 
     In addition, light-emitting elements  130  with different wavelengths or different density arrangements, could be disposed on the holding curvy surfaces W 1  and at the same time the light-emitting time or light-emitting frequency could be adjusted by the control circuit. As a result, the application scope of the illumination device  200  can be improved. The method for controlling the light-emitting module of the light-emitting elements is not being limited herein, and appropriate changes could be made according to the requirements. 
     Conversely,  FIG. 7  is the top view diagram in the perspective angle V 1  of the illumination device in  FIG. 1 . Referring to  FIG. 1  and  FIG. 7 , the light-emitting elements  130  are disposed on the holding curvy surfaces W 1  of the heat dissipation petals  112  with the flexible printed circuit boards  120 . Thus, heat generated by light-emitting elements  130  is able to be dissipated into the heat dissipation channels  114  through the two sidewalls W 2 , W 3 . With the installation direction of the illumination device  100  shown in  FIG. 3 , the heat dissipation channels  114  may be vertically aligned so as to generate an air convection effect for accelerating the heat dissipation. The aforesaid flexible printed circuit boards  120  are strip-shaped, and the orthogonal projection of the flexible printed circuit boards  120  with the light-emitting elements  130  on a normal plane P 2  of the central axis C 1  is radial-shaped or radial-aligned, as shown in  FIG. 7 , and the heat dissipation channels  114  are located between the two sidewalls W 1 , W 2 . As a result, the sidewalls W 2 , W 3  of the heat dissipation petals  112  could be the heat dissipation interface of the illumination device  100 . Specifically, the areas without any flexible printed circuit boards  120  and light-emitting elements  130  disposed thereto, could be used for heat dissipation. Therefore, heat dissipation efficiency of the illumination device  100  and the operating lifespan of the light-emitting elements  130  can be improved. 
       FIG. 8  is a top view diagram of an illumination device in accordance with one exemplary embodiment. Referring to  FIG. 8 , the orthogonal projection of the flexible printed circuit board  320  of the illumination device  300  on the normal plane P 2  of the central axis C 1  is helical-shaped, different from the plurality of flexible printed circuit boards  120  disposed on the holding curvy surfaces W 1  of the heat dissipation petals  112  presented in the aforesaid embodiments. Specifically, the flexible printed circuit board  320  is a helical structure, which is radially extended from the adjacent central axis C 1  along the heat dissipation member  110 , wherein the light-emitting elements  130  are disposed on the helical flexible printed circuit board  320  and positioned on the holding curvy surfaces W 1  of the heat dissipation petals  112 . The light-emitting elements  130  are positioned on the intersections of the flexible printed circuit board  320  and the holding curvy surfaces W 1  of the heat dissipation petals  112 , so as to dissipate heat generated by the light-emitting elements  130  through the heat dissipation petals  112 . In an alternative embodiment (not shown), the orthogonal projection of the flexible printed circuit board on the normal plane of the central axis could be arcuate, circular or concentric circular shaped. 
       FIG. 9  is a schematic diagram illustrating an illumination device in accordance with one exemplary embodiment.  FIG. 10  is an explosion diagram of the illumination device in  FIG. 9 . Referring to  FIG. 8  and  FIG. 10 , apart from the aforesaid embodiments, the heat dissipation member  410  of the illumination device  400  further comprises a connecting part  416  connecting between two adjacent heat dissipation petals  412 , covering parts of the heat dissipation channels  414 , and having identical curvature with the holding curvy surfaces W 1  of the heat dissipation petals  412 . Hence, the connecting part  416  reinforces the structure strength of heat dissipation member  410  while not hindering the air convection within the heat dissipation channels  414 , and the connecting part  416  could also be used as an extension structure of the holding curvy surfaces W 1  of the heat dissipation petals  412  for holding the flexible printed circuit boards  120  and the light-emitting elements  130 . 
     By the way, the connecting part  416  is located at a place with maximum outer diameter of the head portion H 2  and extends toward opposite directions along the central axis C 1 . 
     In addition, the optical element  460  has a plurality of openings  462 , and when the optical element  460  is assembled onto the heat dissipation member  410  for covering the flexible printed circuit board  120  and the light-emitting element  130  thereon, these openings  462  face toward the heat dissipation channels  414  of the heat dissipation member  410  to enhance the heat convection effect of the heat dissipation channels  414 . 
     Moreover, since the heat dissipation member  410  is made of metallic material, the illumination device  400  further comprises an insulating member  470 , which is assembled at the base  140  to insulate the heat dissipation member  410  from the base  140 , so as to prevent the illumination device  400  from malfunctioning during operation. 
       FIG. 11  is schematic diagram illustrating an illumination device in accordance with one exemplary embodiment.  FIG. 12  is an explosion diagram of the illumination device in  FIG. 11 . Referring to  FIG. 11  and  FIG. 12 , the illumination device  500  comprises a plurality of optical elements  560  disposed on the holding curvy surface W 1  of the heat dissipation petal  412  respectively for covering the flexible printed circuit board  120  and the light-emitting elements  130  thereon. In addition, the circuit board  150  in circular-shaped is disposed at an end E 1  of the heat dissipation member  410  away from the base  140 , such that the flexible printed circuit boards  120  in strip-shaped is connected to the margin of the circular-shaped circuit board  150 , and the central axis C 1  of the heat dissipation member  410  passes through the center of the circular-shaped circuit board  150 . 
     Herein, the shape of the disclosed optical element is not being limited, in the aforesaid embodiments of  FIGS. 1 ,  9  and  11  for instance, the appearance of the optical element could be changed according to the requirements of illumination and heat dissipation. In an embodiment (not shown), the optical element  160  (cover) in  FIG. 1  is instead of a plurality of optical lens packed on the light-emitting element  130  respectively, wherein the specification of the lens could be adjusted according to the application requirements. 
       FIG. 13  is schematic diagram illustrating an illumination device in accordance with one exemplary embodiment.  FIG. 14  is an assembly flow-chart of the illumination device in  FIG. 13 . Referring to  FIG. 13  and  FIG. 14 , to complete the assembly of the illumination device  600  in exemplary embodiment, firstly, in step S  140 , dispose the light-emitting elements  130  on the flexible printed circuit board  120 , and then in step S  150 , dispose the flexible printed circuit board  120  with the light-emitting element  130  on the heat dissipation member  610  and locate the light-emitting element  130  on the holding curvy surface W 1 . 
       FIG. 15  is a partial schematic diagram illustrating a heat dissipation member inside of the illumination device in  FIG. 13 .  FIG. 16˜FIG .  18  are schematic diagrams showing parts of the assemblies of the illumination device in  FIG. 13 . Referring to  FIG. 13˜FIG .  18  at the same time, it is worth mentioning that the heat dissipation member  610  is configured by a plurality of heat dissipation petals  612  detachably assembled on the base  140 . In detail, the heat dissipation member  610  comprises a cylinder  616 , which is disposed on the base  140  and has a central axis C 1 , and the cylinder  616  has a plurality of locking chutes  616   a,  located on the cylindrical surface of the cylinder  616 , extending along and about the central axis C 1 . Furthermore, each of the heat dissipation petals  612  has a first positioning pin  612   a  and a second positioning pin  612   b  extending away from the holding curvy surfaces W 1 , and the base  140  has a plurality of inserting slots  144  arranged and surrounded about the central axis C 1 . The second positioning pin  612   b  is locked in the corresponding inserting slot  144 , such that each of the heat dissipation petals  612  is fixed on the base  140 . Therefore, in step S 110 , the cylinder  616  is first assembled to the base  140 . Next in step S 120 , the first positioning pin  612   a  of the heat dissipation petal  612  is locked into the locking chute  616   a,  and in step S 130 , the first positioning pin  612   a  is slid within the locking chute  616   a,  until the second positioning pin  612  of the heat dissipation petal  612  is locked into the corresponding inserting slot  144 . Thus the heat dissipation channels  614  between the two adjacent heat dissipation petals  61  assembled on the cylinder  616  are formed. 
     Then, in step S 160 , the assembled heat dissipation member  610  and base  140  are fixed onto an assembling fixture J 1 , wherein a plurality of fixing bars J 12  of the assembling fixture J 1  penetrate through the heat dissipation channels  614  respectively. Furthermore, referring to  FIG. 13  and  FIG. 17 , the optical element  660  comprises a hemispherical shell portion  662  and a plurality of extension portions  664  that are located at the openings of the hemispherical shell portion  662 . The extension portions  664 , which are extended from the hemispherical shell portion  662 , form into a fence structure, and the fence structure forms another opening  664  opposite to the hemispherical shell portion  662 . The maximum outer diameter R 1  of the heat dissipation member  610  is greater than the inner diameter R 2  of the opening  665 . Herein, the optical element  660  is made of elastic materials, and the optical element  660  is in a spherical-shape without force applied. Accordingly, in step S  170 , the optical element  660  is socketed towards the heat dissipation member  610  with the opening  665  formed by the fence structure, wherein each of the extension portions  664  are automatically aligned between two adjacent fixing bars J 12  with the elastic restoring force of the optical element and moved towards the bottom of the assembling fixture J 1 , and concurrently, the opening  665  is widened due to exertion force from the fixing bars J 12  toward the optical element  660 . Noteworthily, when the heat dissipation member  610  and the base  140  are both fixed at the assembling fixture J 1 , the fixing bars J 12  penetrate through the heat dissipation channels  614  and poke out of the heat dissipation channels  614 . Accordingly, the fixing bars J 12  push up the extension portions  664  during the assembly process of the optical element  660  and then enable the extension portions  664  and the light-emitting elements  130 , which are positioned on the holding curvy surfaces W 1 , to keep a distance to avoid contact of the extension portions  664  with the light-emitting elements  130  by rubbing against each other. 
     Subsequently, in step S 180 , the assembled optical element  660 , heat dissipation member  610  and base  140  are taken out from the assembling fixture J 1 , and the extension portions  664  bind and affix on the holding curvy surfaces W 1  with elasticity. Consequently, with the aforesaid relative structures, the process of assembling the illumination device is completed in a much simplified method. 
     The structure of the heat dissipation member will be described in detail with following embodiments, and the optical element will be omitted for simplicity hereinafter. 
       FIG. 19  is a partial cross-sectional diagram illustrating an illumination device in accordance with one exemplary embodiment. In this embodiment, an orthogonal virtual plane P 3  with reference to the central axis C 2  of the heat dissipation member  710 A is similar to the normal plane P 2  in the embodiment of  FIG. 1 , wherein the central axis C 2  is similar to the central axis C 1  which is shown in a bold dot for being specified more clearly. 
     In the embodiment, the heat dissipation member  710 A comprises a plurality of heat dissipation petals  714 A and a plurality of heat dissipation channels  712 A, wherein each heat dissipation channel  712 A is located on a radial path with reference to the central axis C 2  of the heat dissipation member  710 A. Besides, the heat dissipation member  710 A also comprises a circular body  716 A with the holding curvy surface W 4  that the light-emitting elements  130 C are disposed thereon. 
     Additionally, there exists at least one virtual circle U 1  having a radius R 1  with reference to the central axis C 2  on the orthogonal virtual plane P 3  of the central axis C 2  (i.e., the plane P 3  is extends perpendicular to the central axis C 2 ), and at least two intersections are generated by the virtual circle U 1  and border of the heat dissipation channel  712 A. 
     In other embodiments which are not shown in figures, the virtual circle are overlapped with parts of the heat dissipation channel, or the virtual circle and the heat dissipation channel are tangent. Referring to  FIG. 19 , the virtual circle U 1  is overlapped with the arc of the heat dissipation channel  712 A while the radius of virtual circle U 1  is equal to the radius of the heat dissipation channel  712 A. In other words, the number of intersection generated by the virtual circle and the heat dissipation channel is depend on the radius of the virtual circle. 
     Referring to  FIG. 19 , the heat dissipation member  710 A of the embodiment comprises a plurality of heat dissipation petals  714 A arranged about the central axis C 2 , and each heat dissipation petal  714 A is extended longitudinally along the central axis C 2  and radially with reference to the central axis C 2  (similar to the embodiment of FIG.  1 ), wherein one heat dissipation channel  712 A is defined by two heat dissipation petals  714 A next to each other. 
     In the embodiment, there are four heat dissipation petals  714 A and four heat dissipation channels  712 A staggered and symmetrically arranged about the central axis C 2 , such that the there are eight intersections generated by the virtual circle U 1  and the borders of the four heat dissipation channels  712 A (or heat dissipation petals  714 A). In other embodiments, a number of the intersections generated by the virtual circle and border of the heat dissipation channel could be 2×N, wherein N is positive integral. 
     Besides, a distance R 2  exists between one light-emitting element  130 C and the central axis C 2  on the orthogonal virtual plane P 3 , and the radius R 1  of the virtual circle U 1  is less than the distance R 2 . Moreover, the radius R 1  is greater than a quarter of the distance R 2 , and less than three-quarters of the distance R 2 , such that the heat dissipation petals of the heat dissipation channels could be better defined for better efficiency and structural strength. 
     In the embodiment, the heat dissipation petals  714 A and the heat dissipation channels  712 A are fan-shaped respectively on the orthogonal virtual plane P 3 , wherein an included angle T 1  of the heat dissipation channel  712 A is greater than an included angle T 2  of the heat dissipation petal  714 A, and T 1 +T 2 =90° in accordance with four pairs of heat dissipation petals  714 A and heat dissipation channels  712 A. In other embodiments, the relation of the included angles T 1  and T 2  could be M×(T 1 +T 2 )=360°, wherein M is positive integral, and M is in a range from 3 to 20 for better structural strength of the heat dissipation member  710 A in production. Furthermore, the angle T 1  is existed between two extending lines of the straight-line edges of each heat dissipation petal  714 A on the orthogonal virtual plane P 3 , and the angle T 2  is existed between another two extending lines of two straight-line borders of each heat dissipation channel  712 A on the orthogonal virtual plane P 3 . 
       FIG. 20  a partial cross-sectional diagram illustrating an illumination device in accordance with one exemplary embodiment. In this embodiment, the heat dissipation member  710 B comprises a plurality of heat dissipation channels  712 B and a plurality of heat dissipation petals  714 B arranged and staggered in radial direction with reference to the central axis C 3 , wherein each heat dissipation petals  714 B is extended longitudinally along the central axis C 3 , and at least one heat dissipation channel  712 B is defined by two heat dissipation petals  714 B next to each other. In  FIG. 20 , the heat dissipation channels  712 B and the heat dissipation petals  714 B are concentric about the central axis C 3  on the orthogonal virtual plane P 4 . 
     Additionally, a virtual line L 1  connected between one light-emitting element  130 D and the central axis C 3  is formed on the orthogonal virtual plane P 4  with reference to the central axis C 3 , and at least three intersections are generated by the virtual line L 1  and border of the heat dissipation channels  714 B (or border of the heat dissipation petals  712 B). 
     Referring to  FIG. 20 , the heat dissipation member  710 B has three heat dissipation petals  714 B in circular shape, wherein the outer one has the holding curvy surface W 5  that the light-emitting element  130 D disposed thereon, such that three heat dissipation channels  712 B are defined. In the radial direction with reference to the central axis C 3 , there are five intersections generated by the virtual line L 1  and the border of the heat dissipation channels  712 B (or the heat dissipation petals  714 B). In other embodiments, the number of the intersections could be 2×P+1, wherein P is positive integral. 
       FIG. 21  and  FIG. 22  are partial cross-sectional diagrams illustrating illumination devices in accordance with exemplary embodiments respectively. 
     In the embodiments of  FIG. 21 , the heat dissipation member  710 C are constructed from the heat dissipation petals  714 A,  714 B in the embodiments of  FIG. 19  and  FIG. 20 . Therefore, the heat dissipation channels  712 A,  712 B in circular-shaped and in fan-shaped are defined by the integrated heat dissipation petals  712 A and  714 A. In the embodiment of  FIG. 22 , the heat dissipation member  710 D comprises a plurality of heat dissipation petals  714 B in circular-shaped and a plurality of heat dissipation petals  714 D in bar-shaped, such that the heat dissipation channels  712 A in fan-shaped and the heat dissipation channels  712 B are defined. 
       FIG. 23  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment.  FIG. 24  is a partial cross-sectional diagram on an orthogonal virtual plane P 5  of the illumination device in  FIG. 23 . In the embodiment, the heat dissipation member  710 E has a plurality heat dissipation channels  712 E therein. Each heat dissipation channel  712 E is extended longitudinally along the central axis C 4 , and openings E 2  and E 3  are generated on a surface of the heat dissipation member  710 E by the heat dissipation channel  712 E, wherein the heat dissipation channel  712 E is an through hole connected between a top and a bottom of the heat dissipation member  710 E. Referring to  FIG. 23 , only one dissipation channel  712 E is shown for a representative of four dissipation channel  712 E in  FIG. 24 . In the embodiment, the heat dissipation channel  712 E is parallel to the central axis C 4 , but the disclosure is not limited thereto. In other embodiment, the heat dissipation channel extends along with the curvature of the holding curvy surface or in accordance with the design of air flow for better heat dissipation efficiency. 
     Referring to  FIG. 24 , a virtual circle U 2  is formed on the orthogonal virtual plane P 5  with reference to the central axis C 4 , and one intersection is generated by the virtual circle U 2  and one heat dissipation channel  712 E, and therefore four intersections are generated by the virtual circle U 2  and four heat dissipation channels  712 E. In other words, the number of intersection by the virtual circle and the heat dissipation channel also depends on the number and the disposition of the heat dissipation channel. 
       FIG. 25  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. Referring to  FIG. 25 , the heat dissipation member  710 F has a plurality of heat dissipation channels  712 F, and orthogonal projections of the heat dissipation channels  712 F on the orthogonal virtual plane P 6  are arranged in radial direction with reference to the central axis C 5 , wherein the orthogonal projections of the heat dissipation channels  712 F are in different sizes. Similar to the embodiment of  FIG. 23  and  FIG. 24 , the heat dissipation channels  712 F are through holes extended from a bottom surface to a top surface and passing through a part of the heat dissipation member  710 F. 
       FIG. 26  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. The structure of the heat dissipation member  710 G is an integration of structures of the heat dissipation channels  712 E,  712 F in  FIG. 24  and  FIG. 25  but in different way of disposition. It is noted that the curvature and the disposition of the heat dissipation channels are not limited in embodiments of the disclosure but determined in accordance with the design requirement of the illumination device. 
       FIG. 27  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. In the embodiment, the heat dissipation member  710 H has a plurality of heat dissipation channels  712 H arranged about the central axis C 6 , such that the cross-sectional structure of the heat dissipation member  710 H is in petal-like structure on the orthogonal virtual plane P 7  with reference to the central axis C 6 . Besides, there are a plurality of light-emitting elements  130 E disposed respectively on a bottom surface of each recess  716 H. Each heat dissipation channel  712 H has a line L 3  for separating the heat dissipation channel  712 H into two parts which is mirror to each other (only two lines L 3  are shown in  FIG. 27  for representing the embodiment), and each line L 3  is on the same radial path with reference to the central axis C 6  on the orthogonal virtual plane P 7 . 
       FIG. 28  is a partial cross-sectional diagram of an illumination device in accordance with one exemplary embodiment. In the embodiment, the structure of the heat dissipation member  7101  is an integration of above embodiments that different types of heat dissipation channels  7121 ˜ 7181  are disposed on the heat dissipation member  7101  on an orthogonal virtual plane P 8  with reference to the central axis C 7 . Furthermore, a plurality of light-emitting elements  130 F are disposed on the heat dissipation channels  7281  respectively. 
     Based on the above, the flexible printed circuit board and the light-emitting elements thereon are disposed with the surface profile of the heat dissipation member according to the flexibility of the flexible printed circuit board. Concurrently, with different disposition arrangements of the light-emitting element on the flexible printed circuit board, the illumination device is able to conform to the light distribution of the conventional incandescent bulb in order to enhance the effect of the illumination range of the illumination device. 
     Furthermore, the heat dissipation member is constituted of a plurality of axisymmetric heat dissipation petals with heat dissipation channels formed therebetween, and the light-emitting element is disposed on the heat dissipation petal, and thus the heat generated by the light-emitting element is able to be dissipated more effectively with the disposition arrangement of the heat dissipation petals and the heat dissipation channels. In the disclosed illumination device, the heat dissipation member areas, which are not disposed on the light-emitting elements, may also be used as a heat dissipation interface, so as to enhance heat dissipation efficiency of the illumination device. 
     While the invention has been described and illustrated with reference to specific embodiments thereof, these descriptions and illustrations do not limit the invention. It should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention as defined by the appended claims. The illustrations may not necessarily be drawn to scale. There may be distinctions between the artistic renditions in the present disclosure and the actual apparatus due to manufacturing processes and tolerances. There may be other embodiments of the present invention which are not specifically illustrated. The specification and the drawings are to be regarded as illustrative rather than restrictive. Modifications may be made to adapt a particular situation, material, composition of matter, method, or process to the objective, spirit and scope of the invention. All such modifications are intended to be within the scope of the claims appended hereto. While the methods disclosed herein have been described with reference to particular operations performed in a particular order, it will be understood that these operations may be combined, sub-divided, or re-ordered to form an equivalent method without departing from the teachings of the invention. 
     Accordingly, unless specifically indicated herein, the order and grouping of the operations are not limitations of the invention.