Patent Publication Number: US-2010112511-A1

Title: Reflecting-Type Optical Inspection Apparatus and Related Dental Inspection System

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an optical inspection apparatus used for inspection and examination. More specifically, the invention relates to a reflecting-type optical inspection apparatus having a digital image sensing module for obtaining images of an object through light reflected from a reflective surface. 
     2. Description of Related Art 
     Mouth mirrors are widely used to assist viewing while performing work in a patient&#39;s oral cavity so that a diagnostician, such as a dentist or an ear-nose-and-throat doctor, may, via the reflection of the mouth mirror, obtain an indirect view of otherwise visually-inaccessible areas of the mouth. Also, mouth mirrors could be used to retract the tongue or cheek in order to view an area directly. 
     A conventional mouth mirror has a handle and a reflective mirror. The handle is longitudinal and has a front end. The reflective mirror is mounted on the front end of the handle and has a mirror surface. When the conventional mouth mirror is used, the reflective mirror is inserted into a patient&#39;s mouth cavity to reflect oral tissue. The size of the reflective mirror is as small as a coin for easy placement into the mouth cavity. Due to the limited size of the reflective mirror, however, a diagnostician often has to strain for a good view. Furthermore, the patient does not have a view of his/her own mouth tissue through the mouth mirror, so he or she may not be aware of the condition inside the mouth cavity. 
       FIG. 1  shows an intra-oral inspection system  100  according to the related art. The intra-oral inspection system  100  includes an intra-oral camera  110 , a computer  120  connected to the intra-oral camera  110  via a cable  130 , and a display  140 . As shown in  FIG. 1 , the intra-oral camera  110  has a handle, a head portion, and a camera module  112  situated in the head portion. To observe oral tissue, a diagnostician would insert the head portion and part of the handle of the intra-oral camera  110  into a patient&#39;s mouth cavity. The images obtained by camera module  112  would be transmitted to the computer  120  via the cable  130  and displayed on the display  140 . 
     There is a disadvantage associated with intra-oral inspection system  100 . In particular, a diagnostician would often have to move the intra-oral camera  110  for different viewing angles. However, when the diagnostician moves the intra-oral camera  110  to observe different sides of an object, the image shown on the display  140  often rotates according to changes in the viewing angle of the camera module  112 . Shifting images on the display are distracting to the viewer. This inconveniences the diagnostician watching the image shown on the display  140  and adversely affects the efficiency of the inspection. In addition, the bulky nature of the intra-oral camera  110  also means that certain areas of the mouth cavity will be visually inaccessible. 
     Moreover, post-use disinfection of the intra-oral camera  110  is troublesome, as the intra-oral camera  110  contains electronic components. 
     In view of the foregoing, there is a need for an inspection apparatus that can mitigate or obviate the aforementioned issues in the related art. 
     SUMMARY OF THE INVENTION 
     An exemplary embodiment of reflecting-type optical inspection apparatus is disclosed comprising: a holding portion comprising: a first connector; and a holding component configured for detachably holding an external device having a reflective surface; a connecting portion comprising: a body having a hollow portion; and a second connector formed on the body and engaged with the first connector of the holding portion; and a digital image sensing module disposed in the hollow portion of the body for sensing light reflected from the reflective surface. 
     Another exemplary embodiment of the reflecting-type optical inspection apparatus is disclosed comprising: a holding component configured for detachably holding an external device having a reflective surface; a fastener detachably engaged with the holding component; a first connector attached to the fastener or the holding component; an inner portion having a hollow portion; an outer portion rotatably engaged with the inner portion; at least one limiting structure fixedly attached to the inner portion or the outer portion, formed on the inner portion or the outer portion, or detachable from the inner portion and the outer portion; one or more positioning devices configured for positioning the holding component to a predetermined position; a second connector formed on the outer portion and detachably engaged with the first connector; and a digital image sensing module detachably disposed in the hollow portion of the inner portion for sensing light reflected from the reflective surface. 
     Another exemplary embodiment of the reflecting-type optical inspection apparatus is disclosed comprising: a holding portion configured for detachably holding an external device having a reflective surface; a connecting portion engaged with the holding portion; and a digital image sensing module engaged with the connecting portion for sensing light reflected from the reflective surface. 
     An exemplary embodiment of a dental inspection apparatus is disclosed comprising: a dental mirror having a handle and a reflective surface; a holding portion detachably engaged with the handle of the dental mirror; a handheld digital image sensing module for sensing light reflected from the reflective surface; a connecting portion engaged with the holding portion and the handheld digital image sensing module; and a display electrically coupled with the handheld digital image sensing module for displaying images sensed by the handheld digital image sensing module; wherein the holding portion or at least a part of the connecting portion is rotatable with respect to the handheld digital image sensing module. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an intra-oral inspection system according to the related art. 
         FIG. 2  is a schematic diagram of a reflecting-type optical inspection system according to an exemplary embodiment. 
         FIG. 3  is a perspective view of the reflecting-type optical inspection apparatus depicted in  FIG. 2  according to a first exemplary embodiment. 
         FIG. 4  is an exploded view of the reflecting-type optical inspection apparatus of  FIG. 3 . 
         FIG. 5  is a partial exploded view of the reflecting-type optical inspection apparatus of  FIG. 3 . 
         FIG. 6  is another perspective view of the reflecting-type optical inspection apparatus of  FIG. 3 . 
         FIG. 7  is an exploded view of the handheld digital image sensing module depicted in  FIG. 3 , according to an exemplary embodiment. 
         FIG. 8  is a perspective view of a reflecting-type optical inspection apparatus, according to a second exemplary embodiment. 
         FIG. 9  is an exploded view of the reflecting-type optical inspection apparatus of  FIG. 8 . 
         FIG. 10  is a partial exploded view of the reflecting-type optical inspection apparatus of  FIG. 8 . 
         FIG. 11  is a perspective view of a reflecting-type optical inspection apparatus according to a third exemplary embodiment. 
         FIG. 12  is an exploded view of the reflecting-type optical inspection apparatus of  FIG. 11 . 
         FIG. 13  is a partial exploded view of the reflecting-type optical inspection apparatus of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to exemplary embodiments of the invention, which are illustrated in the accompanying drawings. The same reference numbers may be used throughout the drawings to refer to the same or like parts. 
     Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not in function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. 
     In addition, some embodiments may be described in the context of dentistry; however, such descriptions are exemplary only and shall in no way be interpreted to limit the use of the present invention to the dental field. The reflecting-type optical inspection apparatus and related system of the present invention have practical applications in many fields including, but not limited to, automotive applications, medicine-related applications, industrial applications, and personal hobby applications. 
       FIG. 2  illustrates a schematic diagram of a reflecting-type optical inspection system  200 , according to an exemplary embodiment. The reflecting-type optical inspection system  200  comprises a reflecting-type optical inspection apparatus  210 , a computer  220  coupled with the reflecting-type optical inspection apparatus  210  via a connection  230 , and a display  240  coupled with the computer  220 , wherein the connection  230  may be a physical cable or a wireless link. The term “couple” used herein is intended to mean any indirect or direct connection (e.g., an communication connection; not limited to electrical or optical connections). Accordingly, the display  240  is also coupled with the reflecting-type optical inspection apparatus  210 . In applications, the computer  220  and the display  240  may be replaced by a television or other monitoring devices. For the purpose of explanatory convenience in the following description, it is assumed herein that the reflecting-type optical inspection system  200  is a dental inspection system. 
       FIG. 3  illustrates a perspective view of the reflecting-type optical inspection apparatus  210  depicted in  FIG. 2 , according to a first exemplary embodiment. The reflecting-type optical inspection apparatus  210  comprises a holding component  320 , a fastener  330 , an inner portion  340 , an outer portion  350 , a limiting structure  360 , and a handheld digital image sensing module  390 . The holding component  320  is configured for detachably holding an external device (e.g., a dental mirror in this embodiment)  310  having a reflective surface  314 . The fastener  330  is detachably engaged with the holding component  320 . The outer portion  350  is rotatably engaged with the inner portion  340  and detachably engaged with the holding component  320 . The limiting structure  360  is detachably attached to the outer portion  350  and further secures the outer portion  350  onto the inner portion  340 . The handheld digital image sensing module  390  is detachably engaged with the inner portion  340 . In operations, the handheld digital image sensing module  390  senses light reflected from the reflective surface  314  to obtain images of a target object (such as a tooth)  302 , and transmits obtained images to the computer  220  via the connection  230  so as to show the images on the display  240 . 
     Please refer now to  FIG. 4  and  FIG. 5 .  FIG. 4  is an exploded view of the reflecting-type optical inspection apparatus  210 , and  FIG. 5  is a partial exploded view of the reflecting-type optical inspection apparatus  210 . As shown, the holding component  320  includes a first clamping device  322 , a second clamping device  324 , a first connector  326 , and an elongate protrusion  370 . In this embodiment, the first clamping device  322  is implemented with a flexible grip for holding an elongate handle  312  of the dental mirror  310 . Since the first clamping device  322  is flexible, the dental mirror  310  can detach from the first clamping device  322 . The second clamping device  324  in this embodiment is also implemented with a flexible grip for holding the elongate handle  312  of the dental mirror  310 , so that the holding component  320  can hold the dental mirror  310  in a more stable way. 
     The second clamping device  324  may be omitted in some embodiments where the first clamping device  322  alone is able to stably hold the dental mirror  310 . In addition, the first and second clamping devices  322  and  324  can be replaced by a flexible sleeve where the elongate handle  312  can be inserted thereinto (or pass therethrough) and held. 
     The first connector  326  extends outward from the holding component  320  and has a plurality of projections  328  defined thereon. The first connector  326  connects the holding component  320  with the outer portion  350 . 
     The fastener  330  of this embodiment is implemented with a sleeve having a through hole  332  to which the first clamping device  322  of the holding component  320  can be inserted and secured therein. When the first clamping device  322  is inserted into the through hole  332  of the fastener  330 , the inner surface of the fastener  330  contacts with and presses on the first clamping device  322 , so that the holding component  320  can hold the dental mirror  310  more securely. Instead of a sleeve, the fastener  330  can also be implemented with a clamping device, a hoop, or any other component that can enhance the holding function of the first clamping device  322  when engaged with the holding component  320 . Additionally, the fastener  330  may be omitted in some embodiments where the holding component  320  alone is able to firmly hold the dental mirror  310 . 
     In accordance with the foregoing, the holding component  320  may function alone or cooperate with the fastener  330  to serve as a holding portion of the reflecting-type optical inspection apparatus  210 . 
     As shown in  FIG. 4  and  FIG. 5 , the inner portion  340  of this embodiment includes a light mask  342 , a hollow portion  344 , an annular groove  362 , and a plurality of cavities  372 . The light mask  342  is formed at one end of the inner portion  340 . The hollow portion  344  is a through hole defined longitudinally through the inner portion  340 , and the handheld digital image sensing module  390  is detachably disposed in the hollow portion  344  of the inner portion  340 . The annular groove  362  is formed on the surface of the inner portion  340 . The cavities  372  are defined on an annular outer flange extending radially outward from one end of the inner portion  340 . 
     The outer portion  350  has a base portion having a hollow portion  352  and a second connector  380  formed on the base portion. As shown, the base portion of the outer portion  350  may be made in the form of a sleeve, and the hollow portion  352  may be a rounded through hole defined through the base portion of the outer portion  350 . In this embodiment, the second connector  380  is made in the form of two parallel plates projecting from the base portion of the outer portion  350  and has a slot  384  formed by a gap between the two plates. Each plate of the second connector  380  has a plurality of openings  382  defined thereon. When the first connector  326  of the holding component  320  is inserted into the slot  384  of the second connector  380 , each of the projections  328  on the first connector  326  engages with a corresponding opening  382 , so that the holding component  320  can be connected and secured with the outer portion  350 . 
     When the inner portion  340  is inserted into the hollow portion  352  of the outer portion  350 , the outer portion  350  can rotate with respect to the inner portion  340 , since the hollow portion  352  of the outer portion  350  is a rounded through hole. Thus, the outer portion  350  is rotatably engaged with the inner portion  340 , and the second connector  380  on the outer portion  350  is rotatable with respect to the handheld digital image sensing module  390 . In addition, the holding component  320  is also rotatable with respect to the handheld digital image sensing module  390  if connected with the outer portion  350  through the engagement between the first connector  326  and the second connector  380 . 
     In the above descriptions, the connection between the holding component  320  and the outer portion  350  is detachable. This is achieved by the cooperation of separate parts (i.e., first connector  326  and the second connector  380 ). However, this is simply an exemplary embodiment and should not be interpreted to restrict the present invention in any way. The holding component  320  and the outer portion  350  may be configured to be fixedly connected together and not detachable. For example, the holding component  320  and the outer portion  350  can be integrally formed. 
     The limiting structure  360  of this embodiment is implemented with a mounting collar. After the inner portion  340  is inserted into the hollow portion  352  of the outer portion  350 , the limiting structure  360  is placed around the annular groove  362  of the inner portion  340  and attaches to the outer portion  350  to further secure the outer portion  350  onto the inner portion  340 . Instead of a mounting collar, the limiting structure  360  can be made in the form of a hoop, a sleeve, or any other component that can achieve the same purpose. 
     In addition, the limiting structure  360  may be fixedly attached to the base portion of the outer portion  350  or formed on the base portion of the outer portion  350 . In other embodiments, the limiting structure  360  may be fixedly attached to the annular groove  362  of the inner portion  340  or formed on the surface of the inner portion  340  to replace the annular groove  362 . Moreover, the limiting structure  360  may be omitted in some embodiments where the inner portion  340  and/or the outer portion  350  is dimensioned such that the outer portion  350  can be secured onto the inner portion  340  without the assistance of the limiting structure  360 . 
     In the foregoing descriptions, the handheld digital image sensing module  390  is detachably disposed in the hollow portion  344  of the inner portion  340 . This is merely an exemplary embodiment and should not be interpreted to restrict or limit the present invention in any way. For example, the handheld digital image sensing module  390  can, in another embodiment, be detachably disposed in the hollow portion  352  of the outer portion  350  and directly engaged with the outer portion  350  without using the inner portion  340  as an intermediary between the outer portion  350  and the handheld digital image sensing module  390 . 
     In accordance with the foregoing, the outer portion  350  may function alone or cooperate with the inner portion  340  to serve as a body; and such body may function alone or cooperate with the limiting structure  360  to serve as a connecting portion of the reflecting-type optical inspection apparatus  210 . 
     Please refer now to  FIG. 6 , which is another perspective view of the reflecting-type optical inspection apparatus  210 , as well as  FIG. 4  and  FIG. 5 . As shown, when the first connector  326  of the holding component  320  is inserted into the slot  384  of the second connector  380  on the outer portion  350 , a free end of the protrusion  370  engages with one of the plurality of cavities  372  formed on the annular outer flange of the inner portion  340 . The engagement of the free end of the protrusion  370  and the cavity  372  on the inner portion  340  positions the holding component  320  in a first predetermined position. In this embodiment, four cavities  372  are formed and evenly distributed on the annular outer flange of the inner portion  340 . 
     As the holding component  320  (or the second connector  380 ) rotates with respect to the handheld digital image sensing module  390 , the protrusion  370  bends (e.g., the sufficiently malleable protrusion could flex or arcuate) so that its free end disengages from the original cavity  372 . When the holding component  320  (or the second connector  380 ) rotates 90 degrees with respect to the handheld digital image sensing module  390 , the free end of the protrusion  370  of the holding component  320  would engage with the next cavity  372  on the inner portion  340  and thus position the holding component  320  in a second predetermined position. 
     As can be inferred from the above descriptions, the protrusion  370  on the holding component  320  and the cavities  372  on the inner portion  340  serve as positioning devices for guiding the rotation angle of the holding component  320  (or the second connector  380 ). In some embodiments, the annular outer flange of the inner portion  340  is omitted and the cavities  372  are instead formed on the handheld digital image sensing module  390 . 
     Since the holding component  320  is rotatable with respect to the handheld digital image sensing module  390 , the user is allowed to adjust the observation angle of the dental mirror  310  by rotating the holding component  320  or the outer portion  350  while maintaining the handheld digital image sensing module  390  in the same viewing angle. As a result, a diagnostician could, e.g., rotate the holding component  320  as needed so that the image shown on the display  240  would more or less maintain the same orientation. 
     Additionally, the dental mirror  310  could be a general dental mirror, so the reflective surface  314  can be easily inserted into any position within the mouth cavity, thereby reducing the visually-inaccessible areas of the mouth cavity. Another advantage is that because the dental mirror  310  is detachable from the reflecting-type optical inspection apparatus  210 , the disinfection or replacement of a used dental mirror is very convenient, and would not result in hygienic concerns. 
     Please refer to  FIG. 7 , which illustrates an exploded view of the handheld digital image sensing module  390  according to an exemplary embodiment. The handheld digital image sensing module  390  comprises a back cover  710 , a photo sensor assembly  720 , a cap  730 , at least one guide (two are shown in this embodiment)  740 , a telescopic tube assembly, a casing  780 , and a light module  790 , wherein the telescopic tube assembly of this embodiment comprises an outer tube  750 , an inner tube  760 , and a lens  770 . 
     The back cover  710  comprises two through holes  712  and  714 . In the embodiments where the connection  230  between the reflecting-type optical inspection apparatus  210  and the computer  220  is a physical cable, the connection  230  is connected with the photo sensor assembly  720  via the through hole  712  situated on the back cover  710 . 
     The photo sensor assembly  720  has a circuit board, an optical sensor  722  mounted to the circuit board, a control interface  724  electrically coupled with the circuit board, and at least one electrode (two are shown in this embodiment)  726  formed on the circuit board. When operating, the optical sensor  722  is arranged facing to the lens  770  and senses images from the light passing through the lens  770 . In one embodiment, the control interface  724  is a camera shutter button disposed on the surface of the handheld digital image sensing module  390  via the through hole  714  situated on the back cover  710 . When a user presses the control interface  724 , the control interface  724  triggers a control signal. In response to the control signal, the photo sensor assembly  720  captures and saves the currently sensed image (i.e., the image currently shown on the display  240 ) as an image file. This function facilitates the user in establish the inspection records (e.g., a case history). The control interface  724  may instead be implemented with a touch panel, a voice receiving device, or any other device that can trigger a control signal in responsible to the user&#39;s operation (e g., a finger knock, a vocal command, etc.). 
     The cap  730  is tubular and attached to the back cover  710  and the casing  780 . The cap  730  includes a hollow portion  732 , an inner surface, and at least one protrusion (two are shown in this embodiment)  734 . The photo sensor assembly  720  is disposed in the hollow portion  732 . The protrusions  734  extend radially inward from the inner surface of the cap  730  and each protrusion  734  includes a limiting structure  736 . 
     The casing  780  is tubular and includes a through hole  782 , an inner surface, an opening  784 , and an annular inner flange  786 . The through hole  782  is defined longitudinally through the casing  780 . The opening  784  is defined on a side of the casing  780 . The annular inner flange  786  extends radially inward from the inner surface of the casing  780  and includes at least one limiting structure (two are shown in this embodiment)  788 . 
     The telescopic tube assembly is disposed within the casing  780 . As mentioned previously, the telescopic tube assembly of this embodiment includes the outer tube  750 , the inner tube  760 , and the lens  770 . The outer tube  750  is tubular and disposed rotatably in the through hole  782  of the casing  780 . The outer tube  750  includes an inner surface  752 , at least one spiral track (two are shown in the embodiment)  754 , and an annular knob  756 . The spiral tracks  754  are formed on the inner surface  752  of the outer tube  750 . The annular knob  756  is formed on the outer surface of the outer tube  750  and can be viewed through the opening  784  of the casing  780  when the outer tube  750  is disposed in the through hole  782  of the casing  780 . 
     The inner tube  760  is disposed movably within the outer tube  750  and includes a through hole  762 , an annular outer flange  764 , at least one engaging element (two are shown in this embodiment)  766 , and at least one guiding element (two are shown in this embodiment)  768 . The through hole  762  is defined longitudinally through the inner tube  760 , and the lens  770  is attached to the through hole  762 . The annular outer flange  764  extends radially outward from one end of the inner tube  760  and has an outer edge. 
     The two guiding elements  768  are movably joined with the two spiral tracks  754  of the outer tube  750 , respectively. The implementation of each guiding element  768  may vary with the implementation of the corresponding spiral track  754 . For example, in one embodiment where the spiral track  754  is implemented with a spiral groove, the corresponding guiding element  768  may be implemented with a tab protruding from the inner tube  760  (or formed on the outer edge of the annular outer flange  764  of the inner tube  760 ). In another embodiment where the spiral track  754  is implemented with a spiral protruding stripe, the corresponding guiding element  768  may be implemented with a matching notch formed on the inner tube  760  (or formed on the outer edge of the annular outer flange  764  of the inner tube  760 ). 
     The light module  790  is disposed at one end of the casing  780  and includes at least one electrode (two are shown in this embodiment)  792 , at least one light source (e.g., LED)  794 , and a through hole  796 . In conventional dental field, a dental lamp is commonly used in combination with a dental mirror to assist viewing while inspecting the oral tissue. The conventional dental lamp provides a large beam of light which may be focused in the general area of a patient&#39;s mouth. The diagnostician&#39;s hands and instruments often shade the area which is being viewed, thereby requiring the diagnostician to keep adjusting his/her posture so as not to shade the area being viewed. During an oral inspection or intra-oral operation, the conventional dental lamp must constantly be adjusted, thereby resulting in considerable time loss and frustration for the diagnostician. The light module  790  can be employed alone or to cooperate with other light source to provide sufficient illumination for intra-oral inspection and operation, and the above problem can therefore be resolved. 
     The two guides  740  are slidably engaged with the inner tube  760  and disposed between the casing  780  and the cap  730 . Each of the two guides  740  has two ends; the first end corresponds to one of the two limiting structures  736  of the cap  730  while the second end corresponds to one of the two limiting structures  788  of the casing  780 . The two guides  740  may be implemented with two guiding rods. 
     In one embodiment, the two limiting structures  736  of the cap  730  are implemented with two mounting holes defined through the protrusion  734 , the two limiting structures  788  of the casing  780  are implemented with two mounting holes defined through the annular inner flange  786 , and the two engaging elements  766  of the inner tube  760  are implemented with two through holes defined through the annular outer flange  764 . In this case, the first end of each guide  740  passes through a corresponding mounting hole (serving as the limiting structure  736 ) of the cap  730  and contacted with a corresponding electrode  726  on the photo sensor assembly  720 , while the second end of the guide  740  passes through a corresponding through hole (serving as the engaging element  766 ) on the annular outer flange  764  of the inner tube  760  and a corresponding mounting hole (serving as the limiting structure  788 ) of the casing  780 , and then contacted with a corresponding electrode  792  on the light module  790 . 
     The guides  740  can be made of conductive materials so that the electricity to the light source  794  of the light module  790  can be conducted via the guides  740 . 
     In the above descriptions, the limiting structures  736 , the limiting structures  788 , and the engaging elements  766  are implemented with mounting holes or through holes. This is merely exemplary and should not be interpreted to restrict or limit the invention in any way. For example, each limiting structure  736  of the cap  730  and each limiting structure  788  of the casing  780  may instead be implemented with a notch or any other structure that is able to limit the transverse movement of a corresponding guide  740 . In addition, each engaging element  766  of the inner tube  760  may instead be implemented with a C-shaped notch or any other structure that can slidably engage with a corresponding guide  740 . 
     Because the two guides  740  are slidably engaged with the two engaging elements  766  of the inner tube  760 , rotating the annular knob  756  of the outer tube  750  would cause the inner tube  760  to slide along the guides  740  in the outer tube  750 . This is due to the relative movement between the spiral tracks  754  of the outer tube  750  and the guiding elements  768  of the inner tube  760 . That is, the inner tube  760  can move longitudinally in the outer tube  750  when the user rotates the outer tube  750  by turning the annular knob  756 . 
     As a result, the magnification of the handheld digital image sensing module  390  can change with the variation of a distance between the optical sensor  722  and the lens  770 . Moreover, the focal length of the handheld digital image sensing module  390  can change with the variation of a distance between the lens  770  and the target object  302  aimed by the handheld digital image sensing module  390 . 
     The magnification and focal length of the handheld digital image sensing module  390  can be changed by adjusting the telescopic tube assembly without replacing the lens  770  or moving the target object  302  aimed by the handheld digital image sensing module  390 . Therefore, the operation of the handheld digital image sensing module  390  is convenient and efficient. 
     Please refer now to  FIG. 8 , which illustrates a perspective view of a reflecting-type optical inspection apparatus  800  according to a second exemplary embodiment. The reflecting-type optical inspection apparatus  800  comprises a holding component  820 , a first connector  826 , a fastener  830 , an inner portion  840 , a light mask  842 , an outer portion  850 , and the handheld digital image sensing module  390 . The holding component  820  is configured for detachably holding the external device (e.g., a dental mirror)  310  having a reflective surface  314 . The fastener  830  is detachably engaged with the holding component  820 . The outer portion  850  is rotatably engaged with the inner portion  840  and detachably engaged with the holding component  820 . The handheld digital image sensing module  390  is detachably engaged with the inner portion  840 . Different from the embodiment shown in  FIG. 3˜FIG .  6 , where the first connector  326  is attached to the holding component  320 , the first connector  826  of this embodiment is detachably attached to the fastener  830 . 
     Referring to  FIG. 9  and  FIG. 10 .  FIG. 9  is an exploded view of the reflecting-type optical inspection apparatus  800 , and  FIG. 10  is a partial exploded view of the reflecting-type optical inspection apparatus  800 . As shown, the holding component  820  includes a first clamping device  822 . In this embodiment, the first clamping device  822  is implemented with a flexible grip for holding an elongate handle  312  of the dental mirror  310 . Since the first clamping device  822  is flexible, the dental mirror  310  can detach from the first clamping device  822 . 
     The first connector  826  includes a second clamping device  824  and a T-shaped plug  828 . The T-shaped plug  828  is employed to connect the first connector  826  with the outer portion  850 . The second clamping device  824  in this embodiment is also implemented with a flexible grip for holding the elongate handle  312  of the dental mirror  310 , so that the dental mirror  310  can be held in a more stable way when the holding component  820  cooperates with the first connector  826  through the connection of the fastener  830 . The second clamping device  824  may be omitted in some embodiments where the first clamping device  822  alone is able to stably hold the dental mirror  310 . In addition, each of the first and second clamping devices  822  and  824  can be replaced by a flexible sleeve where the elongate handle  312  can be inserted thereinto (or pass therethrough) and held. 
     The fastener  830  of this embodiment is implemented with a sleeve having a through hole  832  to which the holding component  820  can be inserted and secured therein. When the first clamping device  822  is inserted into the through hole  832  of the fastener  830 , the inner surface of the fastener  830  contacts with and presses on the first clamping device  822 , so that the holding component  820  can hold the dental mirror  310  more securely. Instead of a sleeve, the fastener  830  can also be implemented with a clamping device, a hoop, or any other component that can enhance the holding function of the first clamping device  822  when engaged with the holding component  820 . Additionally, the fastener  830  may be omitted in some embodiments where the holding component  820  alone is able to firmly hold the dental mirror  310 . 
     From one aspect of the foregoing embodiments, the holding component  820  may cooperate with the fastener  830  and the first connector  826  to serve as a holding portion of the reflecting-type optical inspection apparatus  800 . 
     As shown in  FIG. 9  and  FIG. 10 , the inner portion  840  of this embodiment includes a hollow portion  844 , a limiting structure  862 , and a plurality of openings  872 . The light mask  842  is detachably attached to one end of the inner portion  840 . The hollow portion  844  is a through hole defined longitudinally through the inner portion  840 , and the handheld digital image sensing module  390  is detachably disposed in the hollow portion  844  of the inner portion  840 . The limiting structure  862  is formed on the surface of the inner portion  840 . The openings  872  are defined on the surface of the inner potion  340 . 
     The outer portion  850  has a base portion having a hollow portion  852  and a break  854 , and a second connector  880  formed on the base portion. The outer portion  850  further comprises a flexible arm formed by a protrusion  874  and a U-shaped break  876  defined on the base portion. As shown, the base portion of the outer portion  850  may be made in the form of a sleeve having a C-shaped section. The hollow portion  852  may be a rounded through hole defined through the base portion of the outer portion  850 . In this embodiment, the second connector  880  is made in the form of two parallel bended plates projecting from the base portion of the outer portion  850  and includes a T-shaped slot  882  formed by a gap between the two bended plates. When the first connector  826  of the holding component  820  engages with the second connector  880 , the T-shaped plug  828  on the first connector  826  is inserted into the T-shaped slot  882  of the second connector  880 , so that the first connector  826  can be connected and secured with the outer portion  850 . 
     When the inner portion  840  is inserted into the hollow portion  852  of the outer portion  850 , the outer portion  850  can be rotated with respect to the inner portion  840  since the hollow portion  852  of the outer portion  850  is a rounded through hole. Thus, the outer portion  850  is rotatably engaged with the inner portion  840 , and the second connector  880  on the outer portion  850  and the first connector  826  engaged with the second connector  880  are rotatable with respect to the handheld digital image sensing module  390 . In addition, the fastener  830  and the holding component  820  are also rotatable with respect to the handheld digital image sensing module  390  if attached to the first connector  826 . 
     In the above descriptions, the connection between the first connector  826  and the outer portion  850  is detachable and achieved by the cooperation of separate parts (i.e., the T-shaped plug  828  and the T-shaped slot  882 ). This is merely an exemplary embodiment and should not be interpreted to restrict or limit the present invention in any way. The first connector  826  and the outer portion  850  may be configured to be fixedly connected together and not detachable. For example, the first connector  826  and the outer portion  850  can be integrally formed. 
     The limiting structure  862  of this embodiment is implemented with an annular outer flange formed on the surface of the inner portion  840 . When the inner portion  840  is inserted into the hollow portion  852  of the outer portion  850 , the base portion of the outer portion  850  slightly deforms to allow the limiting structure  862  to pass through. After passing the hollow portion  852 , the limiting structure  862  attaches with the outer portion  850  to further secure the outer portion  850  onto the inner portion  840 . Instead of an annular outer flange, the limiting structure  862  can be made in the form of one or more projections, or any other component that can achieve the same purpose. 
     The limiting structure  862  may be omitted in some embodiments where the inner portion  840  and/or the outer portion  850  is dimensioned such that the outer portion  850  can be secured onto the inner portion  840  without the assistance of the limiting structure  862 . 
     In the foregoing descriptions, the handheld digital image sensing module  390  is detachably disposed in the hollow portion  844  of the inner portion  840 . The handheld digital image sensing module  390  can instead be detachably disposed in the hollow portion  852  of the outer portion  850  and directly engaged with the outer portion  850  without using the inner portion  840  as an intermediary between the outer portion  850  and the handheld digital image sensing module  390 . 
     From one aspect of the foregoing embodiments, the outer portion  850  may function alone or cooperate with the inner portion  840  to serve as a body, and such body may function alone or cooperate with the limiting structure  862  to serve as a connecting portion of the reflecting-type optical inspection apparatus  800 . 
     As shown on  FIG. 9  and  FIG. 10 , when the inner portion  840  is inserted into the outer portion  850 , the protrusion  874  of the flexible arm of the outer portion  850  engages with one of the openings  872  on the inner portion  840 . The engagement of the protrusion  874  and the opening  872  positions the second connector  880  (and the first connector  826  and associated holding component  820 ) in a first predetermined position. In this embodiment, four openings  872  are formed and evenly distributed on the surface of the inner portion  840 . 
     As the holding component  820  (or the second connector  880 ) rotates with respect to the handheld digital image sensing module  390 , the flexible arm of the outer portion  850  deforms so that the protrusion  874  disengages from the original opening  872 . When the holding component  820  (or the second connector  880 ) rotates 90 degrees with respect to the handheld digital image sensing module  390 , the protrusion  874  of the outer portion  850  would engage with the next opening  872  on the inner portion  840  and thus position the holding component  820  in a second predetermined position. 
     As can be inferred from the above descriptions, the protrusion  874  on the outer portion  850  and the openings  872  on the inner portion  840  serve as positioning devices for guiding the rotation angle of the holding component  820  (or the second connector  880 ). In some embodiments where the inner portion  840  is omitted, the openings  872  may instead be formed on the handheld digital image sensing module  390 . 
     Please refer to  FIG. 11 , which illustrates a perspective view of a reflecting-type optical inspection apparatus  1100  according to a third exemplary embodiment. The reflecting-type optical inspection apparatus  1100  comprises a holding component  1120 , a fastener  1130 , the inner portion  840 , the light mask  842 , an outer portion  1150 , and the handheld digital image sensing module  390 . The holding component  1120  is configured for detachably holding the external device (e.g., a dental mirror)  310  having a reflective surface  314 . The fastener  1130  is detachably engaged with the holding component  1120 . The outer portion  1150  is rotatably engaged with the inner portion  840  and detachably engaged with the holding component  1120 . The handheld digital image sensing module  390  is detachably engaged with the inner portion  840 . 
     Referring to  FIG. 12  and  FIG. 13 .  FIG. 12  is an exploded view of the reflecting-type optical inspection apparatus  1100 , and  FIG. 13  is a partial exploded view of the reflecting-type optical inspection apparatus  1100 . As shown, the holding component  1120  includes a first clamping device  1122 , a second clamping device  1124 , and a first connector  1126 . In this embodiment, the first clamping device  1122  is implemented with a flexible grip for holding the elongate handle  312  of the dental mirror  310 . Since the first clamping device  322  is flexible, the dental mirror  310  can detach from the first clamping device  322 . The second clamping device  1124  in this embodiment is also implemented with a flexible grip for holding the elongate handle  312  of the dental mirror  310 , so that the holding component  1120  can hold the dental mirror  310  in a more stable way. 
     The second clamping device  1124  may be omitted in some embodiments where the first clamping device  1122  alone is able to stably hold the dental mirror  310 . In addition, the first and second clamping devices  1122  and  1124  can be replaced by a flexible sleeve where the elongate handle  312  can be inserted thereinto (or pass therethrough) and held. 
     The first connector  1126  extends outward from the holding component  1120  and includes a slot defined therein. The first connector  1126  is employed to connect the holding component  1120  with the outer portion  1150 . Different from the aforementioned reflecting-type optical inspection apparatus  800  where the first connector  826  is detachably attached to the fastener  830 , the first connector  1126  of this embodiment is attached to the holding component  1120 . 
     The fastener  1130  of this embodiment is implemented with a sleeve having a through hole  1132  to which the first clamping device  1122  of the holding component  1120  can be inserted and secured therein. When the first clamping device  1122  is inserted into the through hole  1132  of the fastener  1130 , the inner surface of the fastener  1130  contacts with and presses on the first clamping device  1122 , so that the holding component  1120  can hold the dental mirror  310  more securely. Instead of a sleeve, the fastener  1130  can also be implemented with a clamping device, a hoop, or any other component that can enhance the holding function of the first clamping device  1122  when engaged with the holding component  1120 . Additionally, the fastener  1130  may be omitted in some embodiments where the holding component  1120  alone is able to firmly hold the dental mirror  310 . 
     In accordance with the foregoing, the holding component  1120  may function alone or cooperate with the fastener  1130  to serve as a holding portion of the reflecting-type optical inspection apparatus  1100 . 
     As shown in  FIG. 12  and  FIG. 13 , the inner portion  840  in the reflecting-type optical inspection apparatus  1100  is the same as that in the afore-mentioned reflecting-type optical inspection apparatus  800 . And thus, the descriptions relating to inner portion  840  will not be repeated here. 
     The outer portion  1150  has a base portion having a hollow portion  1152  and a break  1154 , and a second connector  1180  formed on the base portion. The outer portion  1150  further comprises two flexible arms each having a protrusion  1174  and a U-shaped break  1176  defined on the base portion. As shown, the base portion of the outer portion  1150  may be made in the form of a sleeve having a C-shaped section. The hollow portion  1152  may be a rounded through hole defined through the base portion of the outer portion  1150 . In this embodiment, the second connector  1180  extends outward from the base portion of the outer portion  1150  and includes two projections  1182  defined thereon. 
     When the first connector  1126  of the holding component  1120  engages with the second connector  1180 , the projections  1182  on the second connector  1180  are inserted into the slot of the first connector  1126 , so that the holding component  1120  can be connected and secured with the outer portion  1150 . 
     When the inner portion  840  is inserted into the hollow portion  1152  of the outer portion  1150 , the outer portion  1150  can be rotated with respect to the inner portion  840  since the hollow portion  1152  of the outer portion  1150  is a rounded through hole. Thus, the outer portion  1150  is rotatably engaged with the inner portion  840 , and the second connector  1180  on the outer portion  1150  is rotatable with respect to the handheld digital image sensing module  390 . In addition, the holding component  1120  is also rotatable with respect to the handheld digital image sensing module  390  if the holding component  1120  is connected with the outer portion  1150  through the engagement between the first connector  1126  and the second connector  1180 . 
     In the above descriptions, the connection between the first connector  826  and the outer portion  1150  is detachable and achieved by the cooperation of separate parts (i.e., first connector  1126  and the second connector  1180 ). In other embodiments, the first connector  1126  and the outer portion  1150  may be configured to be fixedly connected together and not detachable. For example, the holding component  1120  and the outer portion  1150  can be integrally formed. 
     As described previously, the limiting structure  862  of this embodiment is implemented with an annular outer flange formed on the surface of the inner portion  840 . When the inner portion  840  is inserted into the hollow portion  1152  of the outer portion  1150 , the base portion of the outer portion  1150  slightly deforms to allow the limiting structure  862  to pass through. After passing the hollow portion  1152 , the limiting structure  862  contacts with the outer portion  1150  to further secure the outer portion  1150  onto the inner portion  840 . 
     The limiting structure  862  may be omitted in some embodiments where the inner portion  840  and/or the outer portion  1150  is dimensioned such that the outer portion  1150  can be secured onto the inner portion  840  without the assistance of the limiting structure  862 . 
     Similar to the previous embodiments, the handheld digital image sensing module  390  can instead be detachably disposed in the hollow portion  1152  of the outer portion  1150  and directly engaged with the outer portion  1150  without using the inner portion  840  as an intermediary between the outer portion  1150  and the handheld digital image sensing module  390 . 
     From one aspect of the foregoing embodiments, the outer portion  1150  may function alone or cooperate with the inner portion  840  to serve as a body, and such body may function alone or cooperate with the limiting structure  862  to serve as a connecting portion of the reflecting-type optical inspection apparatus  1100 . 
     As shown in  FIG. 12  and  FIG. 13 , when the inner portion  840  is inserted into the outer portion  1150 , the protrusion  1174  of the flexible arm of the outer portion  1150  engages with one of the openings  872  on the inner portion  840 . The engagement of the protrusion  1174  and the opening  872  positions the second connector  1180  (and associated holding component  1120 ) in a first predetermined position. In this embodiment, four openings  872  are formed and evenly distributed on the surface of the inner portion  840 . 
     As the holding component  1120  (or the second connector  1180 ) rotates with respect to the handheld digital image sensing module  390 , the flexible arm of the outer portion  1150  deforms so that the protrusion  1174  disengages from the original opening  872 . When the holding component  1120  (or the second connector  1180 ) rotates 90 degrees with respect to the handheld digital image sensing module  390 , the protrusion  1174  of the outer portion  1150  would engage with the next opening  872  on the inner portion  840  and thus position the holding component  1120  in a second predetermined position. 
     As can be inferred from the above descriptions, the protrusion  1174  on the outer portion  1150  and the openings  872  on the inner portion  840  serve as positioning devices for guiding the rotation angle of the holding component  1120  (or the second connector  1180 ). 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.