the invention discloses a light - path device , of curved - surface mirror , arranged in a light - path module , wherein a light - path route is designed and adjusted , through the variation of different light - path positions for the curved - surface mirror to focus or disperse the optical image , the entire light - path route is further adjusted . the variation of the execution pattern of the invention is opulent , not only may the design keep the original reflection function in the light - path route , but also may an innovative technique be provided for changing the length of the entire light - path route , such that an impossibly breaking - through problem of the prior arts is solved , and thereby is the quality of the scanned image further improved . the principle of the invention is to apply the design of an image magnification ratio ( m ) in the light - path . the magnification ratio of the image reflected and focused by the reflection mirrors and the lens is matched with the position of the curved - surface mirror for adjusting the magnification ratio , such that the reflection , the focus , and the photoelectric conversion of the image may be completed smoothly . for the magnification ratio of an ordinary document , it must consider the size ( wd ) of the surface of the document , the size ( wc ) of the sensing cell of the photoelectric conversion device , and the diffraction limitation of the lens design , all which may be expressed as following formula : magnification = q ( image size )/ p ( object size )= hi ( image height )/ ho ( object height )=( nc * wc )/ wd wherein , nc is the number applied by the sensing cell of the photoelectric conversion device , so the system magnification ratio ( m system ) may be designed by a manner of separation system ; namely , a formula may be described as the following : m system = m 1 * m 2 * m 3 * . . . mn wherein , n is the number of the separation system . in other words , the magnification ratio ( m system ) of a major system may be designed as the product of the magnification ratios of several separated sub - systems ; in other words , asides from the magnification ratio of the lens &# 39 ; object system , other sub - system &# 39 ; s magnification ratio may be found , and the magnification ratio of the sub - system is adjustable so , adjusting the magnification ratio of the sub - system is to adjust the magnification ratio of the major system , and the design of the entire light - path route is further determined . the curved - surface mirror applied in the invention may be responsible for the character on adjusting the magnification ratio of the sub - system to further adjust the magnification ratio of the entire major system and , by arranging different positions of the curved - surface mirrors , the functions of the convergence ( reduction ) or the dispersion ( magnification ) to the image may be achieved such that , relatively , the design of the curved - surface mirror of the invention has extensive flexibility without the limitation posed by the diffraction extremity of the lens itself , so it can be designed as the following : in such way , the adjustment of the light - path route for the reflection , the focus , and the photoelectric conversion to the image by an entire optical scanner is achieved . for convenient description , in the following embodiment , the reflection device ( including plural reflection mirrors ) and the lens are regarded as a sub - system m lens ; that is , if the plural reflection mirrors and the lens are assumed as a light - path module , then this light - path module may be designed correspondingly with the curved - surface mirror , and the light - path modules for different magnification ratios may then be matched correspondingly with the curved - surface mirrors of different magnification ratios . please refer to fig3 which is a first preferable embodiment according to the invention , which is a light - path device of curved - surface mirror . designing curved - surface mirror in the light - path of a scanner , the length of the light - path route in the light - path device of a scanner may be adjusted , wherein the light - path device 3 includes light - source device ( light source 30 ), light - path module 31 , and photoelectric conversion device 32 ( may be a ccd ), and the light - path module 31 further includes reflection device ( comprised of reflection mirrors 311 , 312 , 313 ) and light - focusing device ( lens 314 ). the light source 30 , providing a light needed by the scanning procedure , irradiates the light penetrating through the transparent supporting glass 16 and incident upon an object 10 ; the reflection mirrors 311 , 312 , 313 sequentially reflect the light reflected from the object 10 placed on the transparent supporting glass 16 to reach a predetermined length of reflective light - path , while the lens 314 , a light - focusing device capable of focusing light into image , receives the light reflected from the reflection mirror 313 and focuses it into an image and , at last , the photoelectric conversion device 32 receives the light of the image focused by the lens 314 and converts it into electric signal . the characteristic of the invention is that a curved - surface mirror 33 is designed between the light - path module 31 and the object 10 , or a curved - surface mirror 34 is designed between the light - path module 31 and the photoelectric conversion device 32 and , in the meantime , one or two of the curved - surface mirrors 33 , 34 may be chosen , such that a design related to the system magnification ratio m system = m lens * m curved - surface mirror described thereinbefore may be fulfilled . the light - path module 31 is designed as a sub - system containing the lens 314 , and the curved - surface mirror 33 or the curved - surface mirror 34 is designed as another sub - system ( only one of the curved - surface mirror 33 or the curved - surface mirror 34 is applied ), then m system = m light - path module * m curved - surface mirror 33 or m system = m light - path module * m curved - surface mirror 34 , wherein the m light - path module is the m lens described thereinbefore . or , when the curved - surface mirror 33 is regarded as a first sub - system and the curved - surface mirror 34 is regarded a second sub - system ( i . e ., the curved - surface mirror 33 and the curved - surface mirror 34 are applied simultaneously ), m system = m light - path module * m curved - surface mirror 33 * m curved - surface mirror 34 , wherein the m light - path module is the m lens described thereinbefore . please refer to fig4 which is the second preferable embodiment according to the invention . as shown in fig4 this preferable embodiment designs the curved - surface mirror 330 between the object 10 and the light - path module 31 , then the light progressing from the object 10 toward the light - path module 31 will be focused ( shrunk ) into the light - path module 31 . in other words , through the curved - surface mirror 330 , the image may be irradiated into the light - path module 31 within a shorter light - path route , so the length of the light - path will be shorter by comparing with that there is no curved - surface mirror 330 . in other words , under the situation that the size of the object 10 is not changed , the curved - surface mirror 330 may adjust the length of the light - path route between the object 10 and the light - path module 3 1 , wherein the curved - surface mirror 330 is a convex mirror ( i . e ., its convex surface is toward the object 10 ). please refer to fig5 which is a third preferable embodiment according to the invention . as shown in fig5 this preferable embodiment is roughly similar to that shown in fig4 . however , the curved - surface mirror 331 is a concave mirror ( i . e ., its concave surface is toward the object 10 ). therefore , any case of convex mirror or concave mirror may all be applied in the invention . by changing the position of the curved - surface mirror in the light - path route , it may relatively change the light - path length between the object 10 and the light - path module 31 . of course , the position in either case of the curved - surface mirror 330 in fig4 or the curved - surface mirror 331 in fig5 may be designed according to the light - path length of actual need . the light - path route summarized from fig3 through fig5 is described sequentially as the following : light - source device ( light source 30 )=& gt ; object 10 =& gt ; curved - surface mirror ( curved - surface mirror 330 or curved - surface mirror 331 )=& gt ; reflection device ( reflection mirrors 311 , 312 , 313 )=& gt ; light - focusing device ( lens 314 )=& gt ; photoelectric conversion device 32 ( ccd ). please refer to fig6 which is the fourth preferable embodiment of the invention . as shown in fig6 this preferable embodiment designs a curved - surface mirror 340 between the light - path module 31 and the photoelectric conversion device 32 , then the light progressing from the light - path module 31 toward the photoelectric conversion device 32 will be dispersed ( magnified ) to the photoelectric conversion device 32 , so the light - path length will be shortened relatively by comparing with there is no curved - surface mirror 340 . namely , under the situation that the size of the photoelectric conversion device 32 is not changed , the curved - surface mirror 340 may adjust the length of the light - path route from the light - path module 31 to the photoelectric conversion device 32 . in other words , the curved - surface mirror 340 may irradiate the image into the photoelectric conversion device 32 with a shorter light - path length , such that the dispersed image will be processed by a photoelectric conversion within the photoelectric conversion device 32 . by changing the position of the curved - surface mirror 340 in the light - path route , it may relatively change light - path length between the photoelectric conversion device 32 and the light - path module 31 . the category of the curved - surface mirror 330 may be a convex mirror or a concave mirror . the light - path route summarized from fig3 through fig6 is described sequentially as the following : light - source device ( light source 30 )=& gt ; object 10 =& gt ; reflection device ( reflection mirrors 311 , 312 , 313 )=& gt ; light - focusing device ( lens 314 )=& gt ; curved - surface mirror ( curved - surface mirror 340 )=& gt ; photoelectric conversion device 32 ( ccd ). please refer to fig7 which is the fifth preferable embodiment of the invention . as shown in fig7 a curved - surface mirror 332 is designed between the light - path module 31 and the photoelectric conversion device 32 , and another curved - surface mirror 341 is designed between the light - path module and the scanned object 10 and , in such design , the size between the light - path module 31 and the photoelectric conversion device 32 and the size between the light - path module 31 and the scanned object 10 may be adjusted simultaneously and , on the other hand , the curved - surface mirror 332 may converge the image to make the photo - image , of the scanned object 10 , after being converged , be then irradiated into the light - path module 31 , while the curved - surface mirror 341 may disperse the image coming from the light - path module 31 , such that the image after being dispersed may be processed by a photoelectric conversion in the photoelectric conversion device 32 . by changing the positions of the curved - surface mirrors 332 , 341 in the light - path route , the flexible design to adjust the entire light - path route may be matched . especially , the length of the entire light - path route may be shortened . furthermore , the volumes of the light - path device and the entire optical scanner may all be reduced , the cost is saved relatively , and the effectiveness of the optical reflection is benefited extremely . the light - path route summarized from fig3 through fig7 is described sequentially as the following : light - source device ( light source 30 )=& gt ; object 10 =& gt ; curved - surface mirror ( curved - surface mirror 332 )=& gt ; reflection device ( reflection mirrors 311 , 312 , 313 )=& gt ; light - focusing device ( lens 314 )=& gt ; curved - surface mirror ( curved - surface mirror 341 )=& gt ; photoelectric conversion device 32 ( ccd ). applied in the invention , the curved - surface mirror positioned in and inter - related with the light - path device appropriately may reach the adjustment and the design of a magnification ratio . by arranging the curved - surface between the scanned document and the light - path module , it may magnify the scanned image and further shorten the size between the scanned object and the light - path module . through the curved - surface mirror designed between the light - path module and the photoelectric conversion device , it may shrink the scanned image and further shorten the size between the light - path module and the photoelectric conversion device . this intricate conception not only breaks through the impossibly resolved problem of the prior arts , but also provides an enhancement of new effectiveness .