Patent Publication Number: US-2017366712-A1

Title: Optical apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation application of U.S. patent application Ser. No. 14/883,012, field Oct. 14, 2015, for which priority is claimed under 35 U.S.C. §120; and this application claims the priority of Application No. 201510541063.2 filed in CHINA on Aug. 28, 2015 and Application No. 103137847 filed in TAIWAN on Oct. 31, 2014 under 35 U.S.C. §119; and hereby incorporates the content of this application by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an optical apparatus, and more particularly to an optical image capturing apparatus with a lighting function. 
     BACKGROUND OF THE INVENTION 
       FIG. 1  schematically illustrates the structure of a conventional image capturing unit. As shown in  FIG. 1 , the image capturing unit  1  comprises an optical lens group  11 , an image sensor  12  and a casing  13 . The optical lens group  11  comprises at least one lens for collecting the light beams from one object to pass through. After the light beam passing through the optical lens group  11  is sensed by the image sensor  12 , the light beam is converted into an image pattern (signal) by the image sensor  12 . According to the imaging signal, a corresponding image is shown on a display device. The optical lens group  11  and the image sensor  12  are accommodated within the casing  13  and securely and firmly positioned in the casing (housing)  13 . Consequently, the optical lens group  11  and the image sensor  12  can be normally operated. In  FIG. 1 , the individual image capturing unit  1  is shown. However, since the current optical technology is constantly developed, the image capturing unit  1  can be minimized and installed in a portable electronic communication product. 
     Moreover, the image capturing unit  1  of  FIG. 1  is only able to capture a single image in each capturing process. Nevertheless, when the demand is to have multiple images simultaneously, a direct approach is to have multiple units which may be too cumbersome. For solving this drawbacks, plural image capturing units  1  are combined together in order to capture plural images at the same time. 
       FIG. 2  schematically illustrates the structure of a conventional array-type image capturing apparatus. As shown in  FIG. 2 , the array-type image capturing apparatus  2  comprises a frame  21  and plural image capturing units  1 . The plural image capturing units  1  are in an array arrangement and in a rectangular distribution through the frame  21 . Moreover, the image signals corresponding to the images acquired by the plural image capturing units  1  are transmitted to a back-end processor (not shown). After the image signals are integrated and processed by the back-end processor, the integrated image is shown on a display device. 
     Generally, the array-type image capturing apparatus  2  is able to capture plural images in each capturing process. However, the optical functions provided by the plural image capturing units  1  are identical. For example, the optical axes of the plural image capturing units  1  are along the same direction. That is, there is no inclined angle between any two optical axes. Alternatively, all image capturing units  1  have the same field of view (FOV) or the same effective focal length (efl). 
     Due to the limitations of the fabricating process of the current array-type image capturing apparatus  2 , the imaging quality of the image capturing unit  1  is usually insufficient. For example, the image capturing unit  1  usually has a resolution of 1 M˜2 M pixels only. Under this circumstance, the function provided by the array-type image capturing apparatus  2  is limited. Moreover, since the array arrangement of the array-type image capturing apparatus  2  is complicated and plural image capturing units  1  are contained in the array-type image capturing apparatus  2 , the applications thereof are restricted because of the high cost. The development of current array type image capturing apparatus are also achieved by wafer-level optics and hence, the lenses are with the same principal planes and hence the same effective focal length and this actually become a restriction on the lens design. It is actually not easy to keep all array elements to have exactly the same effective focal length practically in fabrication/production. 
       FIG. 3  schematically illustrates the structure of another conventional image capturing apparatus. As shown in  FIG. 3 , the image capturing apparatus  9  comprises plural lens modules  91  and a casing  92 . The lens modules  91  are fixed by the casing  92 . Each lens module  91  comprises an optical lens group  911  and an optical sensor (not shown). Moreover, the image signals corresponding to the images acquired by the plural lens modules  91  are transmitted to a processor (not shown). The processor may be built in the casing  92 . After the image signals are integrated and processed by the processor, a three-dimensional image is produced or shown on a display device. Likewise, the image capturing apparatus  9  is able to capture plural images in each capturing process. However, since plural optical sensors are installed within the casing  92 , the volume reduction of the image capturing apparatus  9  is not obvious. 
     Regardless of whether the image capturing apparatus comprises a single image capturing unit or plural image capturing units, the aperture is reduced when the imaging quality of the image capturing apparatus is taken into consideration. The reduction of the aperture can increase the sharpness of the image that is acquired by the image capturing apparatus. However, if the aperture is too small, the luminance for the image capturing apparatus is insufficient. Under this circumstance, the overall performance of the image capturing apparatus is deteriorated. The aperture is related to the concept of f-number. It means that it is always difficult to have small F/# (f-number) for image-taking device in general. 
       FIG. 4  schematically illustrates the structure of another conventional image capturing apparatus with a flash lamp. As shown in  FIG. 4 , the flash lamp  7  is an individual component. The flash lamp  7  may be independently located at the outside of the image capturing apparatus  8 , or the flash lamp  7  may be combined with the image capturing apparatus  8 . During the process of capturing the image, the flash lamp  7  provides luminance to the operating environment of the image capturing apparatus  8 . Consequently, the imaging quality is enhanced. However, since the flash lamp  7  occupies a lot of space, the use of the flash lamp  7  cannot effectively reduce the overall volume of the image capturing apparatus  8 . 
     Therefore, while both of the overall volume and the fabricating cost are taken into consideration, it is an important issue to allow the image capturing apparatus to capture plural images in each capturing process and allow the image capturing apparatus to flexibly provide different optical functions to achieve required optical efficacy according to the practical requirements and acquire required luminance for capturing images in various situations (e.g., the situation that the aperture is reduced). 
     SUMMARY OF THE INVENTION 
     For solving the drawbacks of the conventional technology, the present invention provides an optical apparatus. The optical apparatus has a single optical lens module, and is able to implement different optical functions simultaneously. Consequently, the overall volume of the optical apparatus is minimized, and the fabricating cost of the optical apparatus is reduced. Moreover, the process of assembling the optical apparatus is simplified, and the number of components to be assembled is reduced. 
     For solving the drawbacks of the conventional technology, the present invention provides an optical apparatus. The optical apparatus can provide proper luminance to the operating environment so as to comply with the luminance requirement of the optical sensor. Consequently, the imaging quality and performance of the optical apparatus will be enhanced. 
     In accordance with an aspect of the present invention, there is provided an optical apparatus. The optical apparatus includes plural optical lens groups, an optical sensor, at least one lighting member and a casing. After a light beam passes through any of the plural optical lens groups, a travelling direction of the light beam is changed. After the light beam passes through at least one of the plural optical lens groups, the light beam is sensed by the optical sensor. The at least one lighting member outputs a source beam. The plural optical lens groups, the optical sensor and the at least one lighting member are accommodated and fixed within the casing. 
     In an embodiment, the source beam from the at least one lighting member is a light beam for providing lighting luminance and/or a structured light. 
     In an embodiment, the optical apparatus satisfies a mathematic formula: 
         B   w ≧0.6· E   w ·( F/#   w ) 2  
 
     wherein B w  is a total luminance value of the source beam from at least one the lighting member and with a wavelength w, E w  is a luminance value of the source beam with the wavelength w that is required for the optical sensor, and F/# w  is a f-number of the optical lens group that the source beam with the wavelength passes through. 
     In an embodiment, the optical apparatus satisfies a mathematic formula: 
     
       
         
           
             
               B 
               w 
             
             ≥ 
             
               0.5 
               × 
               
                 
                   ( 
                   
                     f 
                     R 
                   
                   ) 
                 
                 2 
               
               × 
               
                 E 
                 w 
               
             
           
         
       
     
     wherein B w  is a total luminance value of the source beam from at least one the lighting member and with a wavelength w, E w  is a luminance value of the source beam with the wavelength w that is required for the optical sensor, and f is the effective focal length of the optical lens group that the source beam with the wavelength passes through and the R is the corresponding radius of opening. This shows an alternative representation of the minimum luminance required to perform superior imaging. 
     In an embodiment, each lighting member includes a light source and an obstructer, and the obstructer is arranged between the light source and the optical sensor. The source beam from the light source is blocked from being transmitted to the optical sensor by the obstructer. 
     In an embodiment, the light source includes a laser diode (LD), a light emitting diode (LED) and/or an organic light emitting diode (OLED). The light source emits the source beam, and the source beam has a wavelength in a first wavelength range, a second wavelength range and/or a thermal band. 
     In an embodiment, one of the plural optical lens groups is a center optical lens group, and the other optical lens groups of the plural optical lens groups are peripheral optical lens groups around the center optical lens group. 
     In an embodiment, the optical apparatus satisfies mathematic formulae: 
     
       
         
           
             
               0.6 
               &lt; 
               
                 
                   f 
                   c 
                 
                 
                   f 
                   
                     e 
                     , 
                     j 
                   
                 
               
               &lt; 
               2.0 
             
             , 
             
               
                 
                   f 
                   c 
                 
                 
                   F 
                   / 
                   # 
                 
               
               &lt; 
               2.5 
             
             , 
             
               and 
                
               
                   
               
                
               
                 
                   
                     f 
                     c 
                   
                   
                     f 
                     
                       e 
                       , 
                       j 
                     
                   
                 
                 ~ 
                 
                   
                     FOV 
                     
                       e 
                       , 
                       j 
                     
                   
                   
                     FOV 
                     c 
                   
                 
               
             
           
         
       
     
     wherein f c  is an effective focal length of the center optical lens group, f e,j  is an effective focal length of a j-th peripheral optical lens group, and F/# is a f-number of the center optical lens group. FOV c  is used to denote the FOV of central lens group while FOV e,j  is for a j-th peripheral optical lens group. To maintain a minimum opening for the total of the lens groups, when the central portion is with larger FOV, the corresponding f c  will be smaller. On the other hand, when the central portion is with a smaller FOV c , the corresponding f c  will be larger. 
     In an embodiment, an inclined angle between a center optical axis of the center optical lens group and a peripheral optical axis of at least one of the plural peripheral optical lens groups is smaller than 20 degrees. 
     In an embodiment, an inclined angle between a center optical axis of the center optical lens group and a peripheral optical axis of at least one of the plural peripheral optical lens groups is more than 20 degrees when the corresponding lens groups are embedding with reflective optical elements. 
     In an embodiment, the at least one lighting member is disposed within at least one of the plural optical lens groups, or the at least one lighting member is arranged between at least one of the peripheral optical lens groups and the optical sensor. 
     In an embodiment, the optical apparatus according to claim further includes at least one filter. The at least one filter is arranged between the plural optical lens groups and the optical sensor. After the light beam passes through any of the plural optical lens groups, a portion of the light beam is filtered and sieved by the at least one filter. 
     In an embodiment, a visible light beam, an infrared light beam, a near infrared light beam and/or a far infrared light beam is blocked by the at least one filter. 
     In an embodiment, the optical apparatus further includes a light shielding plate. The light shielding plate is located at front sides of the plural optical lens groups, and the light shielding plate has plural perforations corresponding to the plural optical lens groups. 
     In an embodiment, plural optical lens groups include a visible optical lens group and an invisible optical lens group. After at least one visible light beam passes through the visible optical lens group, a travelling direction of the at least one visible light beam is changed. After at least one invisible light beam passes through the invisible optical lens group, a travelling direction of the at least one invisible light beam is changed. 
     In an embodiment, the plural optical lens groups include a first optical lens group with a first lens and a second optical lens group with a second lens, wherein the first lens and the second lens are integrally formed with each other. 
     In an embodiment, each of the plural optical lens groups comprises a single lens or plural lenses in a stack arrangement, wherein each lens is made of a plastic material, a glass material or a silicon-based material. 
     In an embodiment, the optical apparatus is an optical image capturing apparatus. 
     From the above descriptions, the present invention provides the optical apparatus. The plural optical lens groups of the optical apparatus are designed according to different optical functions For example, the optical functions include a wide-angle imaging function, a non-wide angle imaging function, a long-distance imaging function and a short-distance imaging function. Moreover, the plural optical lens groups are fixed in the same casing, and the same optical sensor is shared by the plural optical lens groups. Consequently, the optical apparatus of the present invention has a single optical lens module, and is able to implement different optical functions simultaneously. For example, the optical apparatus can acquire plural images corresponding to different optical functions in each capturing process. For example, the optical apparatus can acquire plural images corresponding to different optical functions in each capturing process. Consequently, the overall volume of the optical apparatus is minimized, and the fabricating cost of the optical apparatus is reduced. Moreover, the optical apparatus further comprises a lighting member for providing proper luminance to the operating environment so as to comply with the luminance requirement of the optical sensor. Moreover, the lighting member and the optical sensor are collaboratively accommodated within the casing. Consequently, the overall volume of the optical apparatus is minimized, and the imaging quality and performance of the optical apparatus are enhanced. 
     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates the structure of a conventional image capturing unit; 
         FIG. 2  schematically illustrates the structure of a conventional array-type image capturing apparatus; 
         FIG. 3  schematically illustrates the structure of another conventional image capturing apparatus; 
         FIG. 4  schematically illustrates the structure of another conventional image capturing apparatus with a flash lamp; 
         FIG. 5  is a schematic perspective view illustrating the outer appearance of an optical apparatus according to a first embodiment of the present invention; 
         FIG. 6  is a schematic cross-sectional view illustrating a portion of the optical apparatus of  FIG. 5  and taken along the line L-L; and 
         FIG. 7  is a schematic cross-sectional view illustrating a portion of an optical apparatus according to a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to  FIGS. 5 and 6 .  FIG. 5  is a schematic perspective view illustrating the outer appearance of an optical apparatus according to a first embodiment of the present invention.  FIG. 6  is a schematic cross-sectional view illustrating a portion of the optical apparatus of  FIG. 5  and taken along the line L-L. In this embodiment, the optical apparatus  3  is an optical image capturing apparatus. The optical apparatus  3  comprises a first optical lens group  31 , a second optical lens group  32 , a third optical lens group  33 , a fourth optical lens group  34 , a lighting member  35 , an optical sensor  36 , a filter  37 , a light shielding plate  38  and a casing  39 . The optical lens groups  31 ˜ 34 , the lighting member  35 , the optical sensor  36 , the filter  37  and the light shielding plate  38  are accommodated within the casing  39 . The first optical lens group  31  comprises a first lens  311 , a third lens  312  and a fifth lens  313 , which are sequentially arranged along the direction of a first optical axis  314 . The second optical lens group  33  comprises a second lens  331 , a fourth lens  332  and a sixth lens  333 , which are sequentially arranged along the direction of a third optical axis  334 . Similarly, the second optical lens group  32  comprises plural lenses (not shown), which are sequentially arranged along the direction of a second optical axis  324 , and the fourth optical lens group  34  comprises plural lenses (not shown), which are sequentially arranged along the direction of a fourth optical axis  344 . The arrangement sequences of the lenses of the second optical lens group  32  and the fourth optical lens group  34  are identical to or different from the arrangement sequences of the lenses of the first optical lens group  31  or the second optical lens group  33 . 
     Moreover, when light beams pass through any of the optical lens groups  31 ˜ 34 , the travelling directions of the light beams are changed. After the light beams pass through any of the optical lens groups  31 ˜ 34 , the light beams are received by the optical sensor  36  and converted into an image signal by the optical sensor  36 . The image signal is processed by a signal processor (not shown) or shown on a display device (not shown). 
     Moreover, each lens is made of a plastic material, a glass material or a silicon-based material. As shown in  FIG. 6 , each of the first optical lens group  31  and the third optical lens group  33  comprises plural lenses, which are in a stack arrangement. It is noted that the number of lenses is not restricted. For example, in some embodiments, each of the optical lens groups  31 ˜ 34  only comprises a single lens. 
     Preferably but not exclusively, the first lens  311  of the first optical lens group  31 , the second lens  331  of the third optical lens group  33 , the corresponding lens of the second optical lens group  32  and the corresponding lens of the fourth optical lens group  34  are connected with each other. That is, these lenses are integrally formed on a single transparent structure. Similarly, the third lens  312  of the first optical lens group  31 , the fourth lens  332  of the third optical lens group  33 , the corresponding lens of the second optical lens group  32  and the corresponding lens of the fourth optical lens group  34  are connected with each other. That is, these lenses are integrally formed. Similarly, the fifth lens  313  of the first optical lens group  31 , the sixth lens  333  of the third optical lens group  33 , the corresponding lens of the second optical lens group  32  and the corresponding lens of the fourth optical lens group  34  are connected with each other. That is, these lenses are integrally formed with each other. 
     Since the corresponding lenses of the optical lens groups  31 ˜ 34  are integrally formed with each other, the optical apparatus  3  can be assembled more easily. Moreover, since the optical apparatus  3  has the advantage of miniaturization, the optical apparatus  3  can be applied to a handheld mobile device such as a mobile phone, a tablet computer or any other wearable device. 
     The light shielding plate  38  is located at the front sides of the optical lens groups  31 ˜ 34 . Moreover, the light shielding plate  38  has plural perforations  381  corresponding to the optical lens groups  31 ˜ 34 . That is, the optical lens groups  31 ˜ 34  are exposed outside through the corresponding perforations  381 . Consequently, the ambient light beams can be introduced into the optical lens groups  31 ˜ 34 . The light shielding plate  38  is used for sheltering the surrounding stray light around the optical lens groups  31 ˜ 34 . Consequently, the optical resolution of the light beams to be sensed by the optical sensor  36  will be enhanced. 
     The filter  37  is arranged between the optical lens groups  31 ˜ 34  and the optical sensor  36 . After the light beams pass through the optical lens groups  31 ˜ 34 , portions of the light beams are filtered and sieved by the filter  37 . Consequently, the light beams received by the optical sensor  36  are useful light beams. For example, according to the practical requirements, the filter  37  is designed to block visible light beams, infrared light beams, near infrared light beams and/or far infrared light beams. 
     In this embodiment, the third optical lens group  33  is a center optical lens group, and the first optical lens group  31 , the second optical lens group  32  and the fourth optical lens group  34  are peripheral optical lens groups around the center optical lens group. That is, these peripheral optical lens groups are arranged around the center optical lens group  33 . 
     Moreover, these optical lens groups  31 ˜ 34  have respective effective focal lengths (EFL). Since the optical lens groups  31 ˜ 34  may comprise different numbers and/or different optical properties of lenses, the effective focal lengths of any two optical lens groups are identical or different. In an embodiment, f c  is an effective focal length of the center optical lens group (i.e., the effective focal length of the third optical lens group  33 ), f e,j  is an effective focal length of the j-th peripheral optical lens group (i.e., f e,j  is the effective focal length of the first optical lens group  31 , f e,2  is the effective focal length of the second optical lens group  32 , and f e,3  is the effective focal length of the fourth optical lens group  34 ), and F/# is a f-number of the center optical lens group (i.e., the f-number of the third optical lens group  33 ). Moreover, the optical apparatus  3  satisfies the following mathematic formulae: 
     
       
         
           
             
               0.6 
               &lt; 
               
                 
                   f 
                   c 
                 
                 
                   f 
                   
                     e 
                     , 
                     j 
                   
                 
               
               &lt; 
               2.0 
             
             , 
             
               
                 
                   f 
                   c 
                 
                 
                   F 
                   / 
                   # 
                 
               
               &lt; 
               2.5 
             
             , 
             
               and 
                
               
                   
               
                
               
                 
                   
                     f 
                     c 
                   
                   
                     f 
                     
                       e 
                       , 
                       j 
                     
                   
                 
                 ~ 
                 
                   
                     FOV 
                     
                       e 
                       , 
                       j 
                     
                   
                   
                     FOV 
                     c 
                   
                 
               
             
           
         
       
     
     FOV c  is used to denote the FOV of central lens group while FOV e,j  is for a j-th peripheral optical lens group. To maintain a minimum opening for the total of the lens groups, when the central portion is with larger FOV, the corresponding f c  will be smaller. On the other hand, when the central portion is with a smaller FOV c , the corresponding f c  will be larger. 
     That is, the quotient of the effective focal length of the third optical lens group  33  divided by the effective focal length of the first optical lens group  31 , the second optical lens group  32  or the fourth optical lens group  34  is in the range between 0.6 and 1.2, and the quotient of the effective focal length of the third optical lens group  33  divided by the f-number of the third optical lens group  33  is smaller than 2.5. Consequently, the performance of converting the received light beam into the image signal by the optical sensor  36  will be enhanced. 
     Preferably but not exclusively, the inclined angle between the third optical axis  334  of the third optical lens group  33  and each of the first optical axis  314  of the first optical lens group  31 , the second optical axis  324  of the second optical lens group  32  and the fourth optical axis  344  of the fourth optical lens group  34  is smaller than 20 degrees. That is, the inclined angle between the center optical lens group and any peripheral optical lens group is smaller than 20 degrees. Consequently, the imaging performance of the optical apparatus  3  is enhanced. When the tilted angle is required to be larger than 20 degrees, additional reflective optical elements can be embedded to achieve the specification. The inclination of optical axes is achieved, e.g., by having one prism element or reflective mirror element in between lens elements  331  and  312 . In this case, the optical axis  314  is tilted, and to have less optical aberration, the lens element  331  is also tilted correspondingly. The barrel  38  is also partially modified to hold the lens element  311  respectively such that the optical axis  314  can have the inclined angle as specified, e.g., 20 degrees, and hence the total field of view can be enlarged greatly as one example of application. 
     Optionally, one of the plural optical lens groups  31 ˜ 34  is a visible optical lens group and another of the plural optical lens groups  31 ˜ 34  is an invisible optical lens group. After a visible light beam passes through the visible optical lens group, a travelling direction of the visible light beam is changed. After an invisible light beam passes through the invisible optical lens group, a travelling direction of the invisible light beam is changed. 
     It is acknowledged that if the luminance of the operating environment of the optical apparatus  3  is insufficient or the aperture of any of the optical lens groups  31 ˜ 34  is too small, the luminance of the light beam to enter into the optical sensor  36  will be insufficient for the optical sensor  36  to perform well. Thus, in the present invention, the lighting member  35  is used for providing proper luminance to the operating environment of the optical apparatus  3  so as to comply with the luminance requirement of the optical sensor  36  and enhance the performance of converting the received light beam into the image signal by the optical sensor  36 . Accordingly, the imaging performance and function of the optical apparatus  3  will be enhanced by equipping the lighting member  35 . 
     In this embodiment, the lighting member  35  comprises a light source  351  and an obstructer  352 , which are in a stack arrangement. The obstructer  352  is arranged between the light source  351  and the optical sensor  36 . By the obstructer  352 , the light beam (also referred as a source beam) emitted by the light source  351  is blocked from being transmitted to the optical sensor  35 . Consequently, the light beam emitted by the light source  351  is only permitted to be outputted to the surroundings of the optical apparatus  3  in a single direction. In another embodiment, the lighting member  35  further comprises a diffractive optical element (not shown) according to the practical requirements. After the light beam emitted by the light source  351  passes through the diffractive optical element, a structured light is outputted from the optical apparatus  3 . 
     For example, the light source  351  comprises a laser diode (LD), a light emitting diode (LED), an organic light emitting diode (OLED), or any other comparable semiconductor-type light-emitting element similar to the laser diode, the light emitting diode or the organic light emitting diode. The wavelength of the light beam from the light source  351  is in a first wavelength range and/or a second wavelength range. For example, the light beam from the light source  351  is a visible beam, an invisible beam or a light beam in a thermal band. 
     Optionally, the lighting member  35  further comprises an optical component that cooperatively works with the light source  351 . For example, the optical component is a lens  353 . The lens  353  is connected with the first lens  311  of the first optical lens group  31  and the second lens  331  of the third optical lens group  33 . After the light beam from the lighting member  35  passes through the lens  353 , a travelling direction of the light beam is changed. 
     Preferably but not exclusively, B w  is the total luminance value of the light beam from the lighting member  35  and with a wavelength w, E w  is the luminance value of the light beam with the wavelength w that is required for the optical sensor  36 , and F/# w  is a f-number of the center optical lens group that the light beam with the wavelength passes through. Moreover, the optical apparatus  3  satisfies the following mathematic formula: 
         B   w ≧0.6· E   w ·( F/#   w ) 2  
 
     The required luminance can be rewritten as 
     
       
         
           
             
               B 
               w 
             
             ≥ 
             
               0.5 
               × 
               
                 
                   ( 
                   
                     f 
                     R 
                   
                   ) 
                 
                 2 
               
               × 
               
                 E 
                 w 
               
             
           
         
       
     
     Wherein B w  is a total luminance value of the source beam from at least one the lighting member and with a wavelength w, E w  is a detectable luminance value of the source beam with the wavelength w by the optical sensor, and f is the effective focal length of the optical lens group that the source beam with the wavelength passes through and the R is the corresponding radius of opening. This shows an alternative representation of the minimum luminance required to perform superior imaging. 
     According to the above mathematic formula, the lighting member  35  provides the proper luminance to the operating environment of the optical apparatus  3  so as to comply with the luminance requirement of the optical sensor  36 . This shows a minimum luminance required to perform superior sensitivity. Consequently, the imaging performance and function of the optical apparatus  3  will be enhanced. 
       FIG. 7  is a schematic cross-sectional view illustrating a portion of an optical apparatus according to a second embodiment of the present invention. The components of the optical apparatus  3 ′ of this embodiment which are similar to the optical device of the first embodiment are not redundantly described herein. In the first embodiment, the lighting member  35  comprises a single light source  351 . Whereas, the lighting member  35 ′ of the optical apparatus  3 ′ of this embodiment comprises plural light sources  351  and  354 . 
     It is noted that the present invention is limited to the above embodiment. Those skilled in the art will readily observe that numerous modifications and alterations may be made while retaining the teachings of the invention. For example, in a variant example, the optical apparatus is not equipped with the filter  37 . In another variant example, the optical apparatus is not equipped with the light shielding plate  38 . In the above embodiments, the light shielding plate  38  is located at the front sides of the optical lens groups. In some other embodiments, the light shielding plate  38  is located at another proper position of the optical apparatus. For example, the light shielding plate  38  is arranged between two optical lens groups, or the light shielding plate  38  is arranged between two lenses of a specified optical lens group. 
     In the above embodiments, the optical apparatus comprises a single filter  37 . In some other embodiments, the optical apparatus comprises plural filters corresponding to plural optical lens groups. Optionally, according to the special requirements, any two filters are designed to block the same kind of light beams or block different kinds of light beams. 
     In the above embodiment, the plural optical lens groups of the optical apparatus are specially designed. That is, the peripheral optical lens groups are arranged around the center optical lens group. It is noted that the distribution of the plural optical lens groups is not restricted. For example, in some other embodiments, the plural optical lens groups are in a rectangular distribution. 
     From the above descriptions, the present invention provides the optical apparatus. The plural optical lens groups of the optical apparatus are designed according to different optical functions For example, the optical functions include a wide-angle imaging function, a non-wide angle imaging function, a long-distance imaging function and a short-distance imaging function. Moreover, the plural optical lens groups are fixed in the same casing, and the same optical sensor is shared by the plural optical lens groups. Consequently, the optical apparatus of the present invention has a single optical lens module, and is able to implement different optical functions simultaneously. For example, the optical apparatus can acquire plural images corresponding to different optical functions in each capturing process. Consequently, the overall volume of the optical apparatus is minimized, and the fabricating cost of the optical apparatus is reduced. Moreover, the process of assembling the optical apparatus is simplified, and the number of components to be assembled is reduced. 
     Moreover, the optical apparatus further comprises a lighting member for providing proper luminance to the operating environment so as to comply with the luminance requirement of the optical sensor. Moreover, the lighting member and the optical sensor are collaboratively accommodated within the casing. Consequently, the overall volume of the optical apparatus is minimized, and the imaging quality and performance of the optical apparatus are enhanced. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.