CN2404161Y - Scanner with moving element backlight - Google Patents

Abstract

A scanner of movable backlight device for scanning a manuscript is composed of an image pick-up unit and a backlight unit, which can generate light beam to be imaged on said image pick-up unit.

Description

Scanner with moving element backlight

The utility model relates to a scanner of a moving part type backlight device with low manufacturing cost and high scanning quality.

According to the different documents to be scanned, flatbed scanners can be broadly divided into reflective scanners and transmissive scanners. Reflective scanners are suitable for scanning opaque documents such as papers, documents, and books; transmissive scanners are suitable for scanning transparent documents such as transparencies and positives. Generally, the scanning light sources of transmissive scanners on the market can be divided into two types: moving part type and fixed type, which are described as follows:

Please refer to FIG. 1 for a schematic diagram of a conventional transmissive scanner using a movable light source. Wherein, the manuscript 12 is placed on the glass plane 13 , and the lamp tube 11 and the optical module 14 (including the charge-coupled device 15 ) move precisely and synchronously, so that the graphics on the manuscript 12 are imaged on the charge-coupled device 15 . There are multiple implementation modes for the detailed structure and operation of this mechanism, one of which can refer to Taiwan Patent Publication No. 311791.

However, the illumination intensity distribution of the lamp (light source) 11 is very steep, as shown in FIG. 2 , and the optical module 14 and the lamp 11 are located on different mechanisms, requiring an additional mechanism to move them synchronously, so it is difficult to synchronize accurately. In case the optical module 14 fails to move accurately and synchronously with the lamp tube 11, the light intensity received by the charge-coupled device 15 will vary greatly, resulting in poor uniformity of the image signal obtained by scanning the document.

Please refer to FIG. 3 for a schematic diagram of a conventional transmissive scanner using a fixed light source. Wherein, the fixed light source is a backlight device 31 (as disclosed in Taiwan Publication No. 292032 Patent), which includes a lamp tube 311 , a reflector 315 , a light guide plate 317 and a diffuser plate 316 . Reflective points 318 are engraved on the light guide plate 317 to further improve the uniformity of light emission of the backlight device 31 . The transparent manuscript 32 is placed on the glass plane 33, and the light generated by the lamp tube 311 is evenly distributed through the large-area reflector 315, the light guide plate 317, and the diffusion plate 316, and then passes through the manuscript 32 to be imaged by the charge-coupled on device 35. When this type of scanner is scanning, the backlight device (ie, the light source) 31 is fixed, and only the optical module 34 moves.

The above-mentioned backlight device 31 (fixed light source) is equipped with mechanisms such as the reflector 315, the light guide plate 317, the diffuser plate 316, etc., so that the light intensity distribution produced by it is quite uniform, but in terms of the current technical level, the backlight device 31 There is still a 5% to 10% difference in light intensity between the center and the edge, which is still unacceptable for high-resolution scanners. Moreover, the larger the size of the light guide plate 317 is, the worse the uniformity of light reflection will be. In addition, the reflection point 318 on the light guide plate 317 is not easy to engrave. The larger the area of the light guide plate 317, the more difficult the engraving technique is, and the high price is not in line with the benefits.

In view of this, the purpose of the present utility model is to provide a scanner of a movable element backlight device with low manufacturing cost and high scanning quality.

The purpose of this utility model is achieved by providing a scanner with a movable backlight device for scanning a manuscript, which includes: a backlight device that can generate light; An image capture device for forming an image through the light of the manuscript; according to the order of the light paths, the manuscript is located between the backlight device and the image capture device, and the backlight device and the image capture device are The manuscript is scanned while moving in synchronization.

The advantage of the device of the present invention is that since the backlight device moves synchronously with the image capture device during scanning, the size of the backlight device does not need to be too large, and the size of the light guide plate arranged in it does not need to be too large, so it can be easily used. The entire backlight device can achieve acceptable light uniformity, and the manufacturing cost of the light guide plate can also be greatly reduced.

Below in conjunction with accompanying drawing, describe embodiment of the present utility model, wherein:

FIG. 1 is a schematic diagram of an existing transmissive scanner using a moving element light source;

Fig. 2 is the distribution diagram of the irradiation intensity of the lamp tube light source in the existing transmissive scanner adopting the moving part light source;

3 is a schematic diagram of an existing transmissive scanner using a fixed light source;

FIG. 4 is a schematic diagram of a scanner of the moving element backlight device of the present invention.

Please refer to FIG. 4 for a schematic diagram of the scanner of the movable element backlight device of the present invention. Among them, the light source is a backlight device 41 , which includes a light tube 411 , a small-area reflection sheet 415 , a light guide plate 417 , and a diffuser plate 416 . Reflective points 418 are engraved on the light guide plate 417 to further improve the lighting uniformity of the backlight device 41 . The manuscript 42 is placed on the glass plane 43 , and the light generated by the lamp tube 411 is evenly distributed through the reflector 415 , the light guide plate 417 and the diffusion plate 416 , and then transmitted through the manuscript 42 to be imaged on the charge-coupled device 45 . During scanning, the backlight device 41 moves synchronously with the optical module 44 .

Since the backlight device 41 moves synchronously with the optical module 44 during scanning, the size of the backlight device 41 does not need to be too large, and the internal reflector 415, light guide plate 417, and diffusion plate 416 can be small in size, and the light guide plate 417 There are fewer reflection points 418 on the surface, and the production cost will be greatly reduced. In addition, because the utility model adopts a small-sized light guide plate, the light generated is more uniform than that of a fixed scanner. The difference in light intensity between the center and edge of the manuscript in the utility model is within 1%. 5% to 10% difference in light intensity of the standard scanner. On the other hand, due to the small area of the light guide plate 417, the utility model only needs to use one lamp tube to achieve the desired effect, which is more cost-effective than the existing fixed light source scanner using two lamp tubes ( Existing scanners with fixed light sources must use two lamp tubes because of the large area of the light guide plate).

Compared with the transmission scanner of the existing movable part light source, the utility model adopts a backlight device to replace the existing lamp tube. The light uniformity of the backlight device is much better than that of the lamp tube, so even if the mechanism design is not ideal, resulting in the optical module not being able to accurately move synchronously with the backlight device, the light intensity received by the charge-coupled device will not change greatly , so a certain scan quality can be maintained.

Compared with the existing transmissive scanners with fixed light sources, the utility model adopts small-sized reflectors, light guide plates and diffusion plates, so the cost of the backlight device itself is low and the quality rate is high, and because of its uniform brightness, the The charge-coupled device can maintain a certain scanning quality during the scanning process.

All the above are explained by taking the transmissive scanner as an example, but the present invention can also be applied to the reflective and transmissive dual-purpose scanners for scanning transparent manuscripts, which is hereby stated.

Claims (6)

1. A scanner of a moving part type backlight device, which is used to scan a manuscript, is characterized in that it comprises: a backlight device that can generate light; one for passing the light produced by the backlight device through the manuscript And the image capture device for imaging; according to the order of its optical path, the manuscript is located between the backlight device and the image capture device, and the backlight device and the image capture device move synchronously to scan the manuscript. 2. The scanner with a moving element backlight device according to claim 1, wherein the scanner further comprises a glass plane for carrying the document, and the backlight device and the image capture device are located on the Different sides of the glass plane. 3. The scanner with a moving element backlight device according to claim 1 or 2, wherein the backlight device is composed of a light tube and a light guide plate. 4. The scanner of the movable element backlight device according to claim 3, wherein the backlight device further comprises a reflection sheet and a diffusion sheet for improving the uniformity of the light emitted by the backlight device . 5 . The scanner with a movable element backlight device as claimed in claim 3 , wherein the number of lamp tubes included in the backlight device is exactly one. 6 . 6 . The scanner of a moving element backlight device as claimed in claim 4 , wherein the number of lamp tubes included in the backlight device is exactly one. 6 .

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