Embodiments of the invention disclose a light-path device of an optical scanner that includes a curved-surface optical element and a light-path module. The arrangement between the curved-surface optical element and the light-path module may be designed such that the length of a light-path route through the light-path device may be adjusted to accommodate various sized objects to be scanned and physics characteristics of the photoelectric conversion device included in the scanner to convert the image into an electrical signal.