Installation for improving a scanning range of scanner along an axial direction of a light source

Abstract

An installation for increasing the usable scanning range along the axial direction of a light source. The installation includes a linear light source and a light-channeling panel. The linear light source has a light axis whose brightness near the mid-portion is higher than the brightness level on either side. The light-channeling panel is adjacent to the linear light source and is capable of concentrating more light in the end sections rather than the mid-portion of the light axis. The light-channeling panel is made from a plurality of panels, each made from materials having different light transparencies. The light transparency of the light-channeling panel near the central section of the light axis is lower than the light transparency at the end sections of the light axis. Hence, after light from the linear light source has passed through the light-channeling panel, a band of light having a more homogenous brightness level than the linear light source is produced.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the priority benefit of Taiwan application serial no. 88222560, filed Dec. 18, 1999.BACKGROUND OF THE INVENTION[0002]1. Field of Invention[0003]The present invention relates to the light source of a scanner. More particularly, the present invention relates to an installation for improving a scanning range of a scanner along an axial direction of a light source.[0004]2. Description of Related Art[0005]In general, a scanning system can be roughly classified as a reflective type or a light-penetrating type. In the reflective scanning system, a document is placed over a transparent glass panel. Light from a light source travels through the transparent glass panel and impinges upon the document. The light is reflected back from the document to reach an optical sensor after passing through a set of optical elements. The optical sensor for forming a scan image, for example, can be a charge couple device (CCD). In the light...

AI Technical Summary

Benefits of technology

[0012]Accordingly, one object of the present invention is to modify a component in a scanner so that the useful range along the axial direction of a light source is increased. The component is a light-channeling panel and the modification is a variation of light transparency across the surface of the light-channeling panel.

[0013]To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides an installation for increasing the useful range along the axial direction of a light source. The installation includes a linear light source and a light-channeling panel. The linear light source has a light axis whose brightness near the mid-portion is higher than the brightness level on either side. The light source provides a necessary beam of light for image scanning by the scanner.

Problems solved by technology

However, the conventional linear light source of a scanner has one major drawback.

If the variation in brightness level along the axial direction of the light source is large, a section close to both ends of the light axis is unsuitable for forming any images.

Hence, cost of production is high.

However, the reflectivities of more than one reflecting lens need to be modified, thereby increasing the production cost necessary to achieve the results.

Although all the conventional methods are capable of reducing brightness variation along the axial direction of a light source, major structural modification of components are unnecessary.

Images