JPH01265662A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the contrast due to reflection of a lighting light by tilting part of a transparent original support member with respect to an original face and using it for an incident window of a lighting light from the light source. CONSTITUTION:The light radiated from a LED array 103 lights an original face through a transparent original support member 101, picks up information on the original face and the image is formed on a nonmagnification image pickup element by a condenser optical lens array 102. In order to reduce the loss due to reflection in the case of incidence of the light on the support member 101, the tilt angle 105 at the side face of the support member 101 is selected to be below sin<-1>(1/n), where (n) is a refractive index of the support member 101. Through the constitution above, the lighting light from the LED array 103 is made incident with a very small incident angle to the support member 101 and the reflection in the surface of the support member 101 is almost neglected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a mounting structure of a solid-state imaging device in which a same-magnification solid-state imaging device is provided with a light source and an imaging optical system.

[Prior Art] Various solid-state imaging devices using a same-magnification imaging device for reading images have been proposed in image information processing devices such as facsimile machines, copying machines, and scanners. In recent years, with the improvement of 1-magnification image sensors, it has become possible to read a wider range of document surfaces, and each pixel (photoelectric conversion element) that forms the 1-magnification image sensor, that is, the smallest unit that can be divided and read, has been improved. It has become possible to form microscopic structures. Therefore, there is a need for a document reading device that is equipped with a reading optical system that is compatible with a 1-magnification image sensor having such high resolution.

[Problems to be Solved by the Invention] Conventionally, a solid-state imaging device including a light source and an imaging optical system in a same-magnification solid-state imaging device uses an LED array or a fluorescent tube as the light source and a converging optical lens as the imaging optical system. The optical system was constructed using an array or fiber array plate. In the case of a reading device, it is necessary to use a transparent document support material to press the document surface i in order to keep the document surface flat and prevent it from going out of focus.Illumination of the document surface is performed through this transparent document support material. be exposed. FIG. 2 shows a cross-sectional configuration diagram of a conventional solid-state imaging device. In order to make the illumination light incident on the document surface at an incident angle of 45 degrees, the light source 203 is arranged so that the illumination light is made incident on the transparent document support material 201 at an incident angle of 45 degrees. However, since the incident angle is large, not only does the amount of illumination light decrease due to reflection on the surface of the transparent document support material, but also a portion of the reflected light becomes stray light, which is reflected on the converging light lens array 202 and the same-magnification image sensor. There was a problem that the incident light caused the contrast to decrease.

The present invention is intended to solve these conventional problems, and is to provide a solid-state image sensor equipped with a transparent document support material that not only supports the document surface but also efficiently transmits illumination light and prevents a decrease in contrast. The purpose is to provide a device.

[Means for Solving the Problems] In order to solve the above problems, the solid-state imaging device of the present invention includes a life-size image sensor and a royal life-size image of the document surface on the light receiving surface of the life-size image sensor. In a solid-state imaging device including a compound-eye imaging optical system, a transparent document support material disposed between the same-magnification image sensor and a document surface, and a light source, a portion of the transparent document support material is placed between the document surface and the document surface. It is characterized in that it is inclined with respect to the light source and serves as an entrance window for illumination light from the light source.

Hereinafter, the details of the present invention will be shown by examples.

[Example] FIG. 1 is a cross-sectional structural diagram of a solid-state imaging device in an example of the present invention. Light emitted from the LED array 103 as a light source illuminates the document surface through the transparent document support material 101.
Information on the document surface is picked up and imaged by a convergent optical lens array 102 onto a 1-magnification image sensor (so-called contact image sensor).

In order to reduce loss due to reflection when the illumination light is incident on the transparent document support material, it is desirable to reduce the incident angle, and specifically, the angle of incidence is preferably 30 degrees or less.

Therefore, if the refractive index of the transparent document support material 101 is n, the inclination angle 105 of the side surface of the transparent document support material is 5 in-' (1/n
) degree or less. With this structure, the illumination light from the light source 103 can be made to enter the transparent document support material 101 at an extremely small angle of incidence, and reflection on the surface of the transparent document support material can be almost ignored. Become.

Furthermore, since the illumination light incident window of the transparent original support material 101 is not located in a position opposite to the lens end surface of the converging light lens array 102 and is inclined with respect to the lens end surface of the converging light lens array, even if the surface is Even if the illumination light is reflected, the reflected light does not enter the convergent optical lens array 102 or the same-magnification image sensor, and there is no reduction in contrast.

Further, by slightly roughening the surface of the illumination light incident window, although the amount of light is slightly reduced, it is possible to suppress variations in the amount of light.

FIG. 3 shows another embodiment of the transparent document support material of the solid-state imaging device of the present invention, in which the illumination light entrance window is formed on a part of the top surface of the transparent document support material 301 instead of the side surface, but the same effect can be obtained. has. Such an entrance window can be easily created by cutting the surface of the transparent document support material or by embossing plastic or the like.

Note that the document surface used in this specification includes not only the information recording surface but also the surface to be inspected for scratches.

[Effects of the Invention] As described above, according to the present invention, a part of the surface of the transparent document support material disposed between the imaging optical system and the document surface is tilted as an incident window for illumination light, which is effective. This has the effect of allowing the illumination light to be taken in and preventing a decrease in contrast due to reflection of the illumination light on the surface of the transparent document support material.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing an embodiment of the solid-state imaging device of the present invention, and FIG. 2 is a cross-sectional configuration diagram of a conventional solid-state imaging device. FIG. 3 is a cross-sectional configuration diagram showing another embodiment of the solid-state imaging device of the present invention. 101.201,301...Transparent document support material 102.
202,302...Focusing optical lens array 103.2
03,303・ ・LED array 104.204,
304...Illumination light trajectory 105.305...Incidence window 106...Inclination angle or more Applicant Seiko Epson Corporation Representative Patent Attorney Masayoshi Kamiyanagi (1 other person)

Claims (1)

[Claims] A 1-magnification image sensor, a compound-eye imaging optical system that forms an erect 1-size image of a document surface on a light-receiving surface of the 1-magnification image sensor, and a compound-eye imaging optical system arranged between the 1-magnification image sensor and the document surface. A solid-state imaging device comprising a transparent original supporting material and a light source, characterized in that a part of the transparent original supporting material is inclined with respect to the original surface and serves as an incident window for illumination light from the light source. Imaging device.