Scanning apparatus

A scanning apparatus includes a scanning module. The scanning module includes plural light emitting diodes, a porous reflective plate with plural openings, and a reflective element. When the scanning apparatus starts scanning a document, the light beams emitted by the light emitting diodes are directed to the porous reflective plate. A portion of light beams reflected by the porous reflective plate are defined as reflected light beams. The light beams penetrating through the openings are diffracted to be diffractive penetrated light beams. The reflected light beams reflected by the reflective element and the diffractive penetrated light beams are projected on the document, so that enhanced uniform illumination efficacy is achieved.

FIELD OF THE INVENTION

The present invention relates to a scanning apparatus, and more particularly to a scanning apparatus for scanning a document.

BACKGROUND OF THE INVENTION

Scanning apparatuses are widely used for scanning images of documents. The scanned images can be converted into electronic files, which are then stored, processed or spread. With increasing development of scanning technologies, the scanning apparatuses have experienced great growth and are now rapidly gaining in popularity.

FIG. 1is a schematic perspective view illustrating a conventional scanning apparatus. As shown inFIG. 1, the conventional scanning apparatus1comprises a lower casing10and an upper cover11. The lower casing10comprises a glass platform101and a scanning module102. A document P to be scanned is placed on the glass platform101. After the document P is placed on the glass platform101, the lower casing10is covered by the upper cover11, so that the document P is positioned in the scanning apparatus1. During the scanning operation is done, the scanning module102is moved within the lower casing10to scan the document P.

FIG. 2is a schematic cross-sectional view illustrating the conventional scanning apparatus. Hereinafter, the internal structure of the lower casing10of the conventional scanning apparatus1will be illustrated with reference toFIG. 2.

As shown inFIG. 2, in addition to the glass platform101and the scanning module102, the lower casing10further comprises a transmission shaft103and a driving motor104. The scanning module102is installed on the transmission shaft103. The driving motor104is connected with the scanning module102for providing motive power to the scanning module102, so that the scanning module102is moved along the transmission shaft103. The scanning module102comprises a light source1021, a fixed reflective mirror1022, a lens1023and an optical sensing element1024. The light source1021is a lamp tube. The incident light beams L emitted by the light source1021are projected on the document P. The incident light beams L reflected by the document P are then reflected by the fixed reflective mirror1022, and focused by the lens1023. The focused incident light beams L are received by the optical sensing element1024, and then converted into corresponding image signals of the document P.

Hereinafter, a process for performing a scanning operation by the scanning apparatus1will be illustrated with reference toFIGS. 1 and 2. For scanning the document P by the scanning apparatus1, the document P is firstly placed on the glass platform101of the lower casing10. Then, the upper cover11is rotated toward the lower casing10to cover the lower casing10and fix the document P. After the document P is positioned in the scanning apparatus1, the scanning apparatus1is activated, and a scanning operation for scanning the document P starts. The incident light beams L emitted by the light source1021are projected on the document P. The incident light beams L reflected by the document P are then reflected by the fixed reflective mirror1022, and focused by the lens1023. The focused incident light beams L are received by the optical sensing element1024, and thus a first portion of the image of the document P is acquired. Moreover, when the scanning apparatus1is activated, the driving motor104is enabled to drive movement of the scanning module102along the transmission shaft103. That is, the overall document P is scanned while moving the scanning module102along the transmission shaft103. After the scanning operation is finished, the complete image of the document P is acquired.

However, the conventional scanning apparatus1still has some drawbacks. For example, if the incident light beams L emitted by the light source1021are not uniformly projected on the document P, the scanning quality of the scanning module102is deteriorated.

Therefore, there is a need of providing an improved scanning apparatus with enhanced scanning quality.

SUMMARY OF THE INVENTION

An object of the present invention provides a scanning apparatus for generating uniform light beams and projecting the uniform light beams on the document.

Another object of the present invention provides a scanning apparatus with enhanced scanning quality.

In accordance with an aspect of the present invention, there is provided a scanning apparatus for scanning a document to acquire a document image. The scanning apparatus includes a glass platform and a scanning module. The document is placed on the glass platform. The scanning module is used for scanning the document to acquire the document image. The scanning module includes plural light emitting diodes, a porous reflective plate and a reflective element. The plural light emitting diodes emit light beams. The porous reflective plate is arranged beside the plural light emitting diodes, and includes plural first openings and plural second openings. Each first opening and each second opening are arranged at locations relevant to a corresponding light emitting diode. The second opening is arranged beside the first opening. The first opening is smaller than the second opening. The light beams that have penetrated through the plural first openings and the plural second openings are defined as penetrated light beams. The light beams unable to penetrate through the plural first openings and the plural second openings are reflected by the porous reflective plate and defined as reflected light beams. The reflective element is used for receiving and reflecting the reflected light beams from the porous reflective plate, so that the reflected light beams reflected by the reflective element are projected on the document. The penetrated light beams are diffracted by the first openings and the second openings so as to be uniformly projected on the document.

In an embodiment, the first opening has a first diameter, the second opening has a second diameter, the first opening and the second opening are circular, and the first diameter is smaller than the second diameter.

In an embodiment, the plural light emitting diodes are arranged in a line, and the porous reflective plate is substantially an elongated stripe-like plate.

In an embodiment, the scanning apparatus further includes a transmission mechanism. The transmission mechanism is connected with the scanning module for providing motive power to the scanning module, so that the scanning module is moved along the glass platform.

In an embodiment, the scanning module further includes a fixed reflective mirror, a lens and an optical sensing element. The penetrated light beams and the reflected light beams projected on the document are reflected by the document to produce combined reflected light beams. The combined reflected light beams are received and reflected by the fixed reflective mirror. The lens for focusing the combined reflected light beams that are reflected by the fixed reflective mirror. The optical sensing element is used for receiving the combined reflected light beams, thereby acquiring the document image.

In an embodiment, the optical sensing element is a charge coupled device (CCD).

In an embodiment, the reflective element is a reflective mirror.

In an embodiment, the scanning apparatus further includes an upper cover for covering the document that is placed on the glass platform.

In an embodiment, the scanning apparatus further includes an automatic feeder for feeding the document and a second document, thereby facilitating the scanning apparatus to perform a duplex scanning operation or successively scan the document and the second document.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 3is a schematic cross-sectional view illustrating a scanning apparatus according to an embodiment of the present invention. As shown inFIG. 3, the scanning apparatus2comprises an upper cover21, a glass platform22, a scanning module23and a transmission mechanism24. The scanning module23is used for scanning a document P*, thereby acquiring a document image. After the document P* is placed on the glass platform22, the document P* could be scanned by the scanning module23. The upper cover21is used for covering the document P* that is placed on the glass platform22. The transmission mechanism24is connected with the scanning module23for providing motive power to the scanning module23, so that the scanning module23is moved along the glass platform22. The scanning module23comprises plural light emitting diodes231(see alsoFIG. 5), a porous reflective plate232, a reflective element233, a fixed reflective mirror234, a lens235and an optical sensing element236.

FIG. 4is a schematic side view illustrating the scanning module of the scanning apparatus according to an embodiment of the present invention.FIG. 5is a schematic side view illustrating the relation between the plural light emitting diodes and the porous reflective plate according to an embodiment of the present invention. Hereinafter, the configurations and the operating principles of the scanning module23will be illustrated with reference toFIGS. 4 and 5. All of the plural light emitting diodes231are used for emitting light beams. The porous reflective plate232is arranged beside the plural light emitting diodes231. The porous reflective plate232comprises plural first openings2321and plural second openings2322. Each first opening2321and each second opening2322are arranged at locations relevant to a corresponding light emitting diode231. The second opening2322is arranged beside the first opening2321. The first opening2321is smaller than the second opening2322. The reflective element233and the fixed reflective mirror234are used for receiving and reflecting light beams. The light beams reflected by the fixed reflective mirror234are then focused by the lens235. The focused light beams are received by the optical sensing element236, thereby generating a corresponding document image.

In this embodiment, the plural light emitting diodes231are arranged in a line. Since the arrangement of the porous reflective plate232is in coordination with the plural light emitting diodes231, the porous reflective plate232is substantially an elongated stripe-like plate. In the porous reflective plate232, the first opening2321has a first diameter d1, and the second opening2322has a second diameter d2. The first opening2321and the second opening2322are circular. In this embodiment, the first diameter d1is smaller than the second diameter d2. An example of the reflective element233is a reflective mirror. In addition, an example of the optical sensing element236is a charge coupled device (CCD).

For scanning the document P* by the scanning apparatus2, the document P* is firstly placed on the glass platform22. Then, the upper cover21is rotated to cover and fix the document P*. After the document P* is positioned in the scanning apparatus2, the scanning apparatus2is activated, and the scanning apparatus2starts scanning the document P*. The light beams L* emitted by all of the plural light emitting diodes231are directed to the porous reflective plate232. A portion of the light beams L* are reflected by the porous reflective plate232and defined as reflected light beams L1*. The reflected light beams L1* are received and reflected by the reflective element233. As such, the reflected light beams L1* are uniformly penetrated through the glass platform22and uniformly projected on the document P*. On the other hand, a portion of the light beams L* are not reflected by the porous reflective plate232but penetrated through the first openings2311and the second opening2322. During the light beams L* are penetrated through the first openings2311and the second opening2322, the light beams L* are diffracted by the first openings2311and the second openings2322to result in diffractive penetrated light beams L2*. As such, the diffractive penetrated light beams L2* are uniformly projected on the document P* through the glass platform22. The reflected light beams L1* and the penetrated light beams L2* that are projected on the document P* are then reflected by the document P*, and thus combined reflected light beams Ls* are produced. The combined reflected light beams Ls* are directed to the fixed reflective mirror234and reflected by the fixed reflective mirror234. As such, the combined reflected light beams Ls* are directed to the lens235and focused by the lens235. The focused combined reflected light beams Ls* are received by the optical sensing element236, and thus the document image is acquired. Then, the scanning module23is moved by the transmission mechanism24, so that the scanning module23is moved along the glass platform21to scan the whole document P*. After the scanning operation of the scanning module23is finished, the complete image of the document P* is acquired. In an embodiment, the scanning apparatus2is a flatbed image scanner.

For enhancing the scanning quality, the light beams L* emitted by the plural light emitting diodes231need to be uniformly projected on the document P*. Since the porous reflective plate232has openings, the light beams L* are diffracted by the openings to result in diffractive penetrated light beams L2*. The diffractive penetrated light beams L2* can be uniformly projected on the document P* in order to enhance the scanning quality. Generally, the intensity of the light beams emitted by the middle portion of the light emitting diode231is relatively stronger, but the intensity of the light beams emitted by the lateral portion of the light emitting diode231is relatively weaker. Since the light beams emitted by the middle portion of the light emitting diode231are penetrated through the first opening2321and the light beams emitted by the lateral portion of the light emitting diode231are penetrated through the second opening2322, the second opening2322is designed to be larger than the first opening2321. According to the specific design of the present invention, the stronger-intensity light beams penetrative through the porous reflective plate232are less than the weaker-intensity light beams penetrative through the porous reflective plate232. In this situation, the light beams projected on the document P* are homogenized and thus the scanning quality is enhanced.

On the other hand, most of the light beams emitted by the light emitting diodes231are reflected by the porous reflective plate232and the reflective element233to produce the reflected light beams L1*, which are then projected on the document P*. Since the reflected light beams L1* contain a great amount of light beams, the reflected light beams L1* contribute very high brightness. Moreover, after being reflected by the porous reflective plate232and the reflective element233, the reflected light beams L1* become more uniform. In other words, the light beams projected on the document P* will result in high brightness and uniform illumination efficacy so as to enhance the scanning quality.

FIG. 6is a schematic cross-sectional view illustrating a scanning apparatus according to another embodiment of the present invention. As shown inFIG. 6, the scanning apparatus3comprises an automatic document feeder31, a glass platform32, a scanning module33and a transmission mechanism34. The automatic document feeder31is disposed on the glass platform32for feeding plural documents. For clarification, only two documents P1′ and P2′ are shown in the drawings. By means of the automatic document feeder31, the scanning apparatus3could perform a duplex scanning operation, or the successively scan the documents P1′ and P2′. Alternatively, the scanning apparatus3may perform a single-side scanning operation, which is usually performed by a general flatbed image scanner. The scanning module33comprises plural light emitting diodes331(see alsoFIG. 5), a porous reflective plate332, a reflective element333, a fixed reflective mirror334, a lens335and an optical sensing element336. Except for the automatic document feeder31, the configurations and the operating principles of other components included inFIG. 6are similar to those illustrated in the first embodiment, and are not redundantly described herein.

From the above description, the scanning module of the canning apparatus of the present invention includes a porous reflective plate. Before the light beams generated by the light emitting diodes are projected on the document, a portion of the light beams are penetrated through the openings of the porous reflective plate to produce diffractive penetrated light beams, and a portion of the light beams are reflected by the porous reflective plate to produce reflected light beams. The diffractive penetrated light beams and the reflected light beams can be uniformly projected on the document, so that the scanning quality is enhanced.