Rod lens array and image reading device therefrom

Abstract

The invention discloses a rod lens array with large depth of field and an image reading device therefrom. The rod lens array is characterized by comprising at least one first rod lens array and at least one second rod lens array, wherein the first rod lens array consists of a plurality of first rod lenses with a first conjugate length TC1, a first height Z1 and a first diameter phi 1 and the second rod lens array consists of a plurality of second rod lenses with a second conjugate length TC1, a second height Z1 and a second diameter phi 1, the at least one first rod lens array and the at least one second rod lens array are sandwiched between a first side plate and a second side plate which are used for supporting, and resin is used for bonding and fixing the first rod lens array and the second rod lens array to the first side plate and the second side plate. The rod lens array has large depth of field, can effectively solve image degradation because the original manuscript position deviates the normal focal position during high speed image reading process and can improve image reading quality.

Description

technical field [0001] The present invention relates to a rod lens array and an image reading device, more specifically to a rod lens array that combines two lens arrays with different properties to form a long depth of field rod lens array, and a rod lens array formed using the rod lens array image reading device. Background technique [0002] Generally, in image reading devices such as scanners and all-in-one machines, there is an image reading device that converts the pattern information on the original document into electrical information and then saves it in the memory of the device or sends it to a computer for storage. This image reading device mainly includes a light source, a rod lens array and a photoelectric conversion sensor. Among them, the rod lens array plays the role of focusing and imaging, which determines the performance of the image reading device to a large extent. [0003] figure 1 It is a schematic diagram of a partial structure of a rod lens arra...

AI Technical Summary

Problems solved by technology

[0008] The above-mentioned rod lens array and image reading device have the following problems: since only when the original is in the focus position plane of the rod lens array 2, that is, on the surface of the light-transmitting plate of the image reading device, the image signal read by the image reading device is clear, as long as the original is slightly out of focus, the read image quality will be significantly reduced

It is feasible for image reading devices with very low reading speed in the past, such as flatbed scanners and all-in-one machines whose originals are fixed on the surface of the light-transmitting plate, or facsimile machines whose originals are driven close to the surface of the light-transmitting plate , but with the development of technology, the reading speed of the image reading device is getting faster and faster, and it is no longer possible to strictly limit the original to the plane of the focus position. About 1000 sheets / min. At this speed, the original (banknote) almost flies past the surface of the light-transmitting plate when it passes through the image reading device

In high-speed financial equipment, in order to allow the original (banknote) to pass through the image reading device smoothly without jamming, the channel of the original (banknote) has a height of about 2mm, that is, the original (banknote) passes through When the image reading device passes through within 2mm of the focus position of the rod lens array, in such a wide range (depth of field), the existing rod lens array and image reading device can no longer read a clear image , so the existing rod lens array and image reading device can no longer meet this new requirement

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