Contact type image sensor

Abstract

A contact type image sensor is provided with a frame (1). A glass plate (3) is disposed on the frame (1). A circuit board (6) is disposed under the frame (1). A photoelectric conversion chip (7) is disposed on the circuit board (6). A lens (4) is mounted over the photoelectric conversion chip (7). An ultraviolet linear light source (2) is provided at a side of the lens (4). The ultraviolet linear light source (2) is composed of an ultraviolet LED (5-1), a light guide body (5-3), a light guide plate (5-4), and a LED circuit board (5-2). Light guide patterns (5-5), being the grooves on the light guide body, are provided on the light guide body (5-3).

Description

Technical field [0001] The invention relates to an image reading device, in particular to a contact image sensor in which the ultraviolet linear light source is a light guide. Background technique [0002] We know that the existing contact image sensor with ultraviolet information identification function used for anti-counterfeiting banknotes in the banking system is provided with a circuit board under the frame, a photoelectric conversion chip is provided on the circuit board, and a lens is installed above the photoelectric conversion chip. The side of the lens is provided with a linear light source, and the linear light source can be arranged on one side of the lens, or on both sides of the lens. Among the linear light sources installed on the side, there is a linear light source that emits ultraviolet light. Since ultraviolet light will be severely attenuated when transmitted in an ordinary light guide body, and the wavelength of ultraviolet light will change when it enco...

AI Technical Summary

Problems solved by technology

[0002] We know that the existing contact image sensor with ultraviolet information identification function used for anti-counterfeiting banknotes in the banking system has a circuit board under the frame, a photoelectric conversion chip is provided on the circuit board, and a lens is installed above the photoelectric conversion chip. The side of the lens is provided with a linear light source, and the linear light source can be provided on one side of the lens, or on both sides of the lens. Among the linear light sources installed on the side, there is a linear light source that emits ultraviolet light. Since ultraviolet light will be severely attenuated when transmitted in an ordinary light guide, and the wavelength of ultraviolet light will change when it encounters ordinary reflection patterns, the ultraviolet light linear light source usually uses ultraviolet light. The structure in the form of an LED array avoids the problem of attenuation of ultraviolet light transmission and wavelength change after ultraviolet light reflection caused by the use of light guides and reflective patterns. The disadvantage of the array form of ultraviolet linear light source is that the number of ultraviolet LEDs used is large and the cost is high. , poor uniformity, and high power consumption. The price of contact image sensors made of array-form ultraviolet light sources is difficult for users to mass-produce. The cost of array-form ultraviolet light sources accounts for 5% of the cost of contact image sensors. More than ten, and the uniformity of the light source is guaranteed by the arrangement density of LEDs. The higher the LED density, the higher the cost

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