Abstract:
Disclosed is an optical needle comprising a needle body, a coupling seat and an optical fiber. The needle body comprises a cavity to accommodate a portion of the optical fiber. The coupling seat provides a junction plane to couple a light source. An end of the needle body is aligned with the junction plane, so to align an end of the optical fiber with the junction plane. The optical needle is characterized in that the long axis of the optical fiber reduces from a section aligned with the junction plane to an end adjacent to the needle body. The coupling interface may be provided in a recess to accommodate the light source. The optical needle may associate a light source. A method for preparation of the optical needle is also disclosed.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an optical needle, more particularly to a puncture needle having light-guiding characteristics, in order to transmit a light beam into an object. 
       BACKGROUND OF THE INVENTION 
       [0002]    The puncture needle is a tool widely used in industry, services and daily life. In many applications, a puncture needle needs to have a light-guiding function. Such applications include industrial detection, medical detection and treatment. 
         [0003]    Recently, stimulations by puncture needles at certain “acupoints” of the human body, in order to improve the physical conditions of a person have become a popular application in many countries. One of such applications is called “acupuncture”, where a puncture needle is inserted into the human body through the skin, to reach the position of an acupoint, and thermal, optical or electrical energy is applied to the acupoint through the puncture needle, in order to stimulate physiological reactions at the acupoint. One way to apply the energy is to burn the external portion of the puncture needle, in order to transmit the thermal energy to the acupoint through the puncture needle. Another way is to apply an electricity to the needle, in order to transmit the electrical energy to the acupoint through the needle. A most recent application of the puncture needle is to apply a light beam, in particular a laser beam, to the acupoint through the puncture needle. 
         [0004]    In order to transmit light beams through a puncture needle, many optical needles to be used in medical or acupuncture applications have been developed. In addition, optical needles for other applications based on transmission of light beams through a puncture needle, such as detections using the light beams so transmitted, have also been developed. 
         [0005]    CN103901233A discloses a probe with an optical fiber. An end of the optical probe is etched to form a tip with an oval end surface. A metal coating is provided around the tip, with the tip exposed from the coating. 
         [0006]    CN104287960A discloses an acupuncture needle with an optical fiber provided inside the acupuncture needle. An end of the optical fiber forms a tapered tip at a micro pore of the tip of the acupuncture needle, to guide a laser beam into a target position of the needle. Other micro pores are provided for the transmission of electrical and optical signals. 
         [0007]    CN204073134 discloses a multi-channel laser treatment equipment, including eight mutually independent laser treatment channels, each including a laser light source and an optical fiber. Laser light is provided in the form of continuous or pulsed irradiations to irradiate an acupoint. 
         [0008]    TW M493360U discloses an optical needle for intravenous irradiations. The optical needle provides a through hole at its base. An end of the through hole may be connected by a tube, to be inserted by an optical fiber, such that the optical fiber passes through the through hole. A cap is provided to seal the through hole, after the optical fiber is sterilized. 
         [0009]    US 2014/0121538A1 discloses an assembly of an optical fiber and a metal needle, which provides a plurality of optical fiber tunnels therein. The tip of the needle forms two tilt angles so that an end of the optical fiber protruding from a second tilt angle, without protruding from the first tilt angle. 
         [0010]    US 2014/0243806A1 discloses a hollow needle with optical fibers embedded therein. A plurality of tunnels is provided in the needle, to accommodate the plurality of optical fibers. A hub is provided to connect the plurality of optical fibers to a laser source. In the hub, a plurality of lightguides is provided, to guide laser beams from the laser source to the respective optical fibers. 
         [0011]    WO 2014/133500A1 discloses a diagnostic probe. The probe includes a needle body provided with a plurality of tunnels to accommodate optical fibers. The respective optical fibers terminate at different longitudinal positions of the needle body, to collect diagnostic information of tissues surrounding the terminals. 
         [0012]    Observations in the development of the optical needle reveal that certain puncture needles have been designed to provide a light-guiding function. These optical needles, however, used a complicated needle body structure. Most optical needles are connected to a separate light source through an optical fiber. In order to connect the lightguide embedded in the optical needle to the optical fiber that is capable of transmitting a light beam for a certain distance, a coupler to align the lightguide and the optical fiber will be necessary. The coupler makes the optical needle system bulky and adds additional costs to the manufacture and application of the system. 
       OBJECTIVES OF THE INVENTION 
       [0013]    The objective of the present invention is to provide a novel structure for the optical needle to enable the integration of the optical needle and a light source. 
         [0014]    Another objective of the present invention is to provide an optical needle that does not need an optical coupler. 
         [0015]    Another objective of the present invention is to provide an optical needle that is connectable to a light source. 
         [0016]    Another objective of the invention is to provide a novel method for the preparation of an optical needle that is connectable to a light source. 
       SUMMARY OF THE INVENTION 
       [0017]    According to this invention, an optical needle is provided and comprises a needle body, a light source coupling seat and a lightguide. The needle body provides a cavity to accommodate a portion of the lightguide. The light source coupling seat provides a junction plane for interfacing a light source and the lightguide. The junction plane may be provided in a recess that can accommodate the light source. An end of the needle body is aligned with the junction plane of the light source coupling seat, such that an end of the lightguide is aligned with the junction plane or the light source. The other end of the lightguide terminates at the tip of the needle body. The optical needle is characterized in that the long axis of the lightguide reduces from a light source section to a needle body section. In certain embodiments, the lightguide is an optical fiber. In the preferred embodiments of the invention, the long axis is diameter of the lightguide. The reduction of the long axis is a continuous reduction or a gradient reduction. 
         [0018]    In a particular embodiment of the invention, the light source coupling seat extends in the radial direction of the lightguide, in order to facilitate insertion of the optical needle into an object. In application, the optical needle is used to transmit light beams into an object, which may be a human tissue. The contact surface of the light source coupling seat with the object may be a substantial plane. The junction plane may also be provided on a protruding portion, which may be engaged in a recess provided in a light source coupler. The tip of the optical needle may form a diagonal cut to facilitate insertion. The top surface of the optical needle may extend to form a plane, to strengthen the combination of the needle body and the light source coupling seat. 
         [0019]    The optical needle of the present invention may further comprise a light source. The light source may be an optical fiber cable or a laser head. If the light source is a laser head, the laser head may comprise a laser beam generator for generating a laser beam; a power supply for providing power to the laser beam generator; a coupler to couple the light source to the coupling seat; and a switch for the control of the power supply. The laser head may provide a coupling portion with a protrusion having a shape complimentary to the shape of the recess of the light source coupling seat. The coupling portion may also have a recess with a shape complimentary to the shape of the protruding portion of the light source coupling seat. The protrusion and/or recess of the coupling portion facilitates stable insertion of the laser lead in the light source coupling seat and the alignment of the light emitting surface of the laser lead to the light source end of the lightguide. 
         [0020]    The present invention also discloses a preparation method of optical needle. The method comprises: preparing a needle body with a hollow cavity; providing a lightguide with a first section, a narrowing section connected to the first section and a second section connected to the narrowing section. The long axis of the lightguide reduces from a junction of the first and narrowing sections to a junction of the narrowing and second sections. The method further comprises: placing the second section of the lightguide in the hollow cavity; if necessary, leaving the first and/or narrowing section outside of the hollow cavity; forming a light source coupling seat with a light source junction plane, such that the light source coupling seat encloses a portion of the needle body and the first and narrowing sections of the lightguide and that a first end of the lightguide is aligned with the light source junction plane, to receive light beams entering through the light source junction plane. The light source junction plane may be provided in a light source accommodation cavity, such that, when the light source coupling seat is formed, the first end of the lightguide is aligned with the light source accommodation cavity. The light source junction plane may also be provided on a protruding portion of the light source coupling seat. 
         [0021]    These and other objectives and advantages of present invention maybe clearly appreciated from the detailed description by referring to the following drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  shows the perspective view of one embodiment of the optical needle of the present invention, while  FIG. 1A  is a schematic diagram of the optical needle of  FIG. 1 , after assembly. 
           [0023]      FIG. 2  shows the cross-sectional schematic view of the optical needle of  FIG. 1 , while  FIG. 2A  is a schematic diagram of the optical needle of  FIG. 1 , after assembly. 
           [0024]      FIG. 3  is the flowchart of the method for preparation of an optical needle in accordance with the present invention. 
           [0025]      FIG. 4  shows the exploded view of one example of a laser head applicable in the optical needle of the present invention, while  FIG. 4A  is a schematic diagram of the laser head of  FIG. 4 , after assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The present invention provides a novel structure of optical needles and its preparation method. The new structure is connectable to a laser source. The present invention also provides an optical needle in combination with a laser source. Although it is not intended to limit the present invention by any theory, the inventor has found that one reason that makes the conventional optical needles complicated in structure is the power consumption of the light source. In order to supply light beams with sufficient power, the light source or laser source is made bulky. In addition, size of lightguide or optical fiber or optical fiber cable used in the optical needle is incompatible with that of the optical fiber used to transmit light beams for a relatively long distance. To connect the lightguide and the optical fiber/cable with high efficiency, a coupler is needed. The inventor also found that the commercially available, small-size laser heads are able to generate laser beams with a wavelength of about 405 nm to 660 nm. The laser beams so generated are sufficient to support most applications of the optical needle, where about 1 mW or stronger light power is needed. In addition, by reducing the long axis or diameter of a lightguide or an optical fiber along the longitudinal direction, the lightguide or optical fiber so obtained would be able to support the coupling of the optical fiber and a light source or a laser source. An invention with these and other features is thus realized. 
         [0027]    In the followings, the optical needle of the present invention will be described by using its several embodiments. It shall be appreciated that description of the embodiments serves merely to illustrate the basic structure and spirit of the present invention. They shall not be used to limit the scope of protection of this invention. 
         [0028]      FIG. 1  shows the perspective view of one embodiment of the optical needle of the present invention and  FIG. 2  shows its cross-sectional view. As shown, the optical needle of the present invention includes a needle body  10 , a light source coupling seat  20  and a lightguide  30 . The needle body  10  has a cavity  11  for receiving the second portion  33  of the lightguide  30 , in this case an optical fiber. 
         [0029]    In the preferred embodiment of the inventions, the needle body  10  may be made from any rigid material. Suitable materials include metal, plastics, glass, or carbon fiber. In the example of  FIGS. 1 and 2 , the top surface of the needle body  10  extends in the lateral direction and forms a disc  12 . The purpose of the disc shape is to strengthen the combination of the needle body  10  and the coupling seat  20 . The inner diameter of the cavity  11  of the needle body  10  may be of a fixed value or reduce from its the top to its tip section. At this tip portion, the inner diameter of the cavity  11  may be about 50 to 500 um, preferably about 100-250 um, and more preferably about 200 um. 
         [0030]    In a preferred embodiment of the present invention, the tip of the needle body  10  may have a diagonal cut (not shown) to facilitate puncture purposes of the needle  10 . The shape of the cut is not limited but is preferably a shape easy to produce. 
         [0031]    The light source coupling seat  20  may be made from a rigid or flexible material. Suitable materials include plastic, silicone, resin and other plastic material. It is also possible to use a metal, ceramic and other materials that are easy to process, to prepare the light source coupling seat  20 . In the example of  FIGS. 1 and 2 , the top surface of the light source coupling seat  20  forms a spherical shape. This, however, is not any technical limitation. For example, the top surface of the coupling seat  20  may be flat, concave or in other shape. The top surface may form a particular pattern or design, by using any applicable technique. In the example of these figures, the coupling seat  20  extends laterally for the convenience of puncturing and inserting the optical needle into an object. This, of course, is not any technical limitation. The object may be a human tissue, such as the aforementioned acupoints of the human body. In such examples, the optical needle may serve as an acupuncture needle. The lower surface of the light source coupling seat  20  is preferably formed a substantial plane, so that the optical needle forms a relatively large contact surface with the object after insertion, to avoid displacement. The lower surface may be formed of other non-planar shape, provided with a pattern, or applied with additional materials. 
         [0032]    In the example of  FIG. 1 , the light source coupling seat  20  provides a recess  21  which is open to the top surface of the coupling seat  20 , whereby a cavity to accommodate a light source  40  is formed. Shape of the opening of the recess  21  preferably complement a contour of the corresponding portion of the light source  40 , so that the light source  40  can be securely received within the recess  21 . After assembly, the optical needle provides a light source junction plane  22  in the light source coupling seat  20 , at a position inside the recess  21  and above the first end  31  of the lightguide  30 . The junction plane  22  is preferably flat. If the light source coupling seat  20  does not provide the recess  21 , the light source junction plane  22  may be provided on the top surface of the light source coupling seat  20 . Therefore, the junction plane  22  and the top surface of the light source coupling seat  20  form substantial flush. In addition, the light source coupling seat  20  may also provide a protruding portion (not shown), at a portion above the first end  31  of the lightguide  30 , so that the protruding portion of the coupling seat  20  may be engaged in a recess (not shown) possibly provided in the light source  40 . Contour of this protruding portion preferably complement shape of the recess of the light source. 
         [0033]    Those having ordinary skills in the art may appreciate that the junction plane  22  provided in the light source coupling seat  20  is not necessarily a physical plane at the surface of an object. The junction plane  22  may be an imaginary plane. Moreover, the junction plane  22  may also be a top surface of the first end  31  of the lightguide  30 . 
         [0034]    The lightguide  30  may be any light guiding material and is preferably an optical fiber. Suitable materials for the lightguide  30  include: glass, plastic, metal oxides and the like. A protective film may be provided on the surface of the lightguide  30 . There is no particularly limitation in the material of the protective film. The cross-sectional shape of the lightguide  30  may be elliptical, but may also be circular, square, or polygonal or in a figure-8 configuration. If necessary, the lightguide  30  can also be a beam with two or more optical fibers twisted together. 
         [0035]    One of the features of the present invention is that the long axis of the lightguide  30  reduces from its light source section (first section)  31  to its needle body end (second section)  33 . When an optical fiber of circular cross-section is used, the long axis is the diameter of the optical fiber. Reduction of the long axis may be a continuous reduction or a gradient reduction. Under this design, the lightguide  30  will include along its length direction: a first section  31 , a narrowing section  32  connected to the first section  31 , and a second section  33  connected to the narrowing section  32 . The first section  31  is aligned with the recess  21  (Embodiment of  FIG. 1 ) of the coupling seat  20 , to be coupled to the light source  40 . The second section  33  is to be disposed within the hollow cavity  11  of the needle body  10 , and to extend to the tip portion of the needle body  10 . The long axis, or diameter, of the lightguide  30  starts to reduce from the junction of the first section  31  and the narrowing section  32  and the reduction ends at the junction of the narrowing section  32  and the second section  33 . In the application of the present invention, the long axis or diameter of the first section  31  may be between 200 um to 1000 um, preferably between 450 um to 500 um. The exact size of the first section  31  is not any technical limitation and is preferably compatible with the size of a light emitting surface of the light source  40 . The long axis or diameter of the second section  33  may be between 30 um to 100 um, preferably between 40 um to 50 um. The exact size of the second section  33  is not any technical limitation and is preferably compatible with the size of an inner diameter of the cavity  11 . If the inner diameter of the cavity  11  at the tip portion is 100 um, the long axis or diameter of the second section  33  may be 50 um, so that the lightguide  30  may be easily disposed in the cavity  11  of the needle body  10 . 
         [0036]    The second section  33  preferably terminates at the needle tip, while it may retract within the needle tip or extend beyond the needle tip. 
         [0037]    Method for forming the narrowing section  32  of the lightguide  30  is not limited but is preferably a technique to produce a graduate or progressive reduction in the long axis of an elongated lightguide, such as an optical fiber. Suitable methods include heating stretch at high temperature, molding and other methods. Among them, stretching at high temperature produces an optical fiber with continuously reduced ling axis; the product is advantageous in transmission of light beams. Molding method forms a lightguide with gradient reduction in ling axis, the advantage of which is accuracy in size of each section. Length of the narrowing section  32  is not particularly limited, but is preferably as short as possible. For example, if the long axis of the first section  31  is 500 um in length and the long axis of the second section  33  is 50 um in length, length of the narrowing section  32  can be 1 mm to 5 mm, so that the reduction ratio is 1/10 to ½ per mm. This ratio can reduce the length of the narrowing section  32 , while efficient transmission of optical power is obtained. Other reduction ratios can also be used in the present invention, to obtain the same or similar effects. In addition, the reduction ratio is not necessarily linear. 
         [0038]    The structure of the needle body  10  is preferably designed to accommodate the narrowing section  32  in the cavity, when the optical fiber  30  is disposed within the needle  10 . If the cavity  11  has a fixed inner diameter along its length direction, the narrowing section  32  and the first section  31  will be disposed external to the cavity  11 , i.e., beyond the top end  12  of the needle body  10 . On the other hand, if the inner diameter of the cavity  11  is progressive, i.e., the inner diameter reduces from the top end  12  to the tip direction, the narrowing section  32  or a portion thereof will be disposed in the cavity  11 . After the lightguide  30  is assembled in the needle body  10 , the top end  12  of the needle body  10  is aligned with the recess  21  of the light source coupling seat  20 , such that end surface of the first section  31  is aligned with the light emitting surface of the light source  40  to be accommodated in the recess  21  of the coupling seat  20 . 
         [0039]    In the followings, a method for preparation of the optical needle of the present invention will be described.  FIG. 3  is the flowchart of the method for preparation of an optical needle in accordance with the present invention. As shown, in the preparation of the optical needle of the present invention, firstly at  301  a needle body  10  is prepared. The needle body  10  has a cavity  11 , with a fixed or progressive diameter along its length direction. The top endo of the needle body  10  may further include a disc  12  extended laterally. Secondly, at step  302  a lightguide  30 , in this case an optical fiber, is prepared. The optical fiber  30  has a first section  31 , a narrowing section  32  connected to the first section  31 , and a second section  33  connected to narrowing section  32 . The long axis of the optical fiber  30  reduces from the junction of the first section  31  and the narrowing section  32  to the junction of the narrowing section  32  and the second section  33 . The reduction may be a gradual reduction or a gradient reduction. Then, at  303  the second section  33  of the optical fiber  30  is disposed in the cavity  11  of the needle body  10 . If the inner diameter of the cavity  11  is fixed, the narrowing section  32  and/or the first section  31  remains outside of the cavity  11 . At  304 , a light source coupling seat  20  with a light source accommodation cavity  21  is formed, to encompass a portion of the needle body  100  and the first section  31  and narrowing section  32  of the lightguide  30 , while having an end surface of the first section  31  aligned with the light source accommodation cavity  21 , in order to receive light beams entering into the light source accommodation cavity  21 . Preparation of the invented optical needle is thus completed. 
         [0040]    In another embodiment of the present invention, the light source coupling seat  20  does not provide the light source accommodation cavity  21  but, instead, a light source junction plane  22  at the top surface of the coupling seat  20 , or even on an protruding portion of the coupling seat  20 . In such embodiments, since a narrowing section  32  that is useful in coupling the optical fiber  30  to an optical fiber cable has been provided, simply irradiating the junction plane  22  with a commercially available laser source, such as a laser pointer, would cause the transmission of light power to the second section  33  of the lightguide  30 . 
         [0041]    In the above steps, the light source coupling seat  20  is preferably formed by molding, such as injection molding. In such examples, the products of step  303  are arranged at suited positions in a mold for the light source coupling seat  20  and maintain their relative positions. A material for the light source coupling seat  20  is filled in the mold to form the coupling seat  20 . After necessary annealing and other process, the optical needle of the present invention is prepared. In order to maintain the relative positions of the lightguide  30  and the needle body  10 , certain positioning tools may be used. The tools will become part of the coupling seat  20  after formation of the coupling seat  20 . 
         [0042]    The optical needle of the present invention may further comprise a light source  40 . The light source  40  may be an optical fiber cable or a laser head. If the light source  40  is an optical fiber cable, an end of the cable will be connected with a light source (not shown), to generate light power needed in the optical needle, whereby the light power may be transmitted to the optical needle through the cable. In such embodiments, the other end of the optical fiber cable may be inserted in the recess  21  of the coupling seat  20 , whereby the narrowing section  32  of the lightguide  30  will couple the light power of the light source to the second section  33  for further use. 
         [0043]    In a preferred embodiment of the present invention, the light source  40  is a laser head.  FIG. 4  shows the exploded view of one example of a laser head  40  applicable in the optical needle of the present invention, while  FIG. 4A  is a schematic diagram of the laser head  40  of  FIG. 4 , after assembly. 
         [0044]    As shown, the laser head  40  includes a laser beam generator  41  for generating a laser beam; a power supply  42  for providing power to the laser beam generator  41 ; and a switch  43  to control the power supply  42 .  FIG. 4  also shows that the laser beam generator  41 , the power supply  42  and the switch  43  are assembled in a coupler  44  and integrated to form a laser head  40 . The coupler  44  provides a coupling end  45 , to function as a light emitting surface of the laser head  40 . The coupler  44  may be inserted in the recess  21  of the light source coupling seat  20 , such that the light emitting surface is aligned with end surface of the first section  31  of the lightguide  30 . In this design, the shape and size of the coupling end  45  is preferably compatible with the recess  21 , so that the laser head  40  can be inserted and securely placed in the light source coupling seat  20 , whereby the light-emitting surface is aligned with end surface of the first section  31  of the lightguide  30 . 
         [0045]    Any small-scale laser light generator can be used in the present invention. For example, the commercially available laser pointer that generates red-color laser beams, is applicable in this invention. Laser light generated by such laser source has a wavelength of about 405 nm to 660 nm, which is sufficient to provide about 1 mW or higher light power, sufficient for most applications of the optical needle. Since this and other laser sources are well known in the art, details thereof is omitted. 
         [0046]    In addition, power supply  42  that supplies electrical power to such a laser source  41  may be any commercially available small-size battery. Micro switch  43  to control such power supply  42  is also known. The combination of the laser light generator  41 , power supply  472  and switch  43  may be determined according to needs in particular applications. Details thereof is also omitted. 
         [0047]    In addition to the types of light source described above, it is also possible to irradiate the junction plane  22  inside the recess  21  or at the top surface of the coupling seat  20  by a commercially available laser source, such as a laser pointer as described above, to achieve the transmission of light powers to the second section  33  of the lightguide  30 . In other words, in application an optical fiber cable or a laser head inserted in the coupling seat  20  is not absolutely necessary. 
         [0048]    As described above, the present invention provides a new structure for the optical needle. The optical needle is connectable with a variety type of light sources, without the need of an additional coupler. A compact and small-size optical needle that is able to reduce the foot print of the optical needle application system is thus provided.