Contact type image sensor

Abstract

The invention relates to an image reading device, in particular to a contact type image sensor in which an ultraviolet linear light source is in a light conductor type. The contact type image sensor comprises a frame, wherein a circuit board is arranged below the frame, and a photoelectric conversion chip is arranged on the circuit board; a lens is arranged above the photoelectric conversion chip, and the light source is arranged at the side face of the lens; and a glass plate is arranged above the frame. The contact type image sensor is characterized in that the linear light source consisting of an ultraviolet light-emitting diode (LED), a light conductor and an LED circuit board is arranged at the side face of the lens, and the ultraviolet LED is arranged at the end of the light conductor. The contact type image sensor provided by the invention has the advantages of low cost, low power consumption, high uniformity, high sensitivity of ultraviolet information identification and the like.

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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