JP2011242526A5

JP2011242526A5 -

Info

Publication number: JP2011242526A5
Application number: JP2010113289A
Authority: JP
Filing date: 2010-05-17
Publication date: 2013-06-27
Anticipated expiration: 2030-05-17

Description

上記目的を達成するために、本発明の画像読取装置は、複数のラインセンサを有する読取手段と、原稿からの光束を前記読取手段に導光する結像光学系と、を備え、前記読取手段を前記複数のラインセンサの配列方向に移動させて前記原稿を読み取る画像読取装置であって、前記配列方向において、前記複数のラインセンサの各々の受光面の幅をＷ、隣り合うラインセンサの中心の間隔をＬ、とするとき、W/L≦0.015なる条件を満たし、前記結像光学系は、少なくとも１面が光軸に対して回転非対称な形状よりなるアナモフィック面であるアナモフィックレンズを含み、前記アナモフィック面の、前記複数のラインセンサの各々の画素の配列方向に垂直な第１の断面内における曲率は、軸上から軸外にかけて連続的に変化しており、

Ｎ：前記アナモフィックレンズの材料の屈折率
ｒ１：前記アナモフィックレンズの入射面の主光線通過位置における前記第１の断面内での曲率半径
ｒ２：前記アナモフィックレンズの出射面の主光線通過位置における前記第１の断面内での曲率半径
ｄ：前記アナモフィックレンズの主光線通過位置における入射面と出射面との間の距離
なる式でＡを定義し、軸上主光線に対する前記Ａの値をA0、前記複数のラインセンサの配列方向に垂直な第２の断面内での全画角における主光線に対する前記Ａの値の最大値をAmax、とするとき、-0.1≦1-(Amax/A0)≦0.1 なる条件を満たすことを特徴とする。 To achieve the above object, an image reading apparatus of the present invention includes a reading unit having a line sensor of multiple, and an imaging optical system for guiding said reading means a light beam from the original, wherein the reading an image reading device for reading the document is moved in the arrangement direction of the plurality of line sensors means, in the arrangement direction, the width of the light receiving surface of each of said plurality of line sensors W, adjacent line sensor when the distance between the centers L, and satisfies W / L ≦ 0.015 following condition, the imaging optical system is an anamorphic surface der Ru anamorphic lens at least one surface of the rotationally asymmetric shape with respect to the optical axis wherein, of said anamorphic surface, curvature those of the first cross-section perpendicular to the arrangement direction of each pixel of said plurality of line sensors is continuously changed toward the off-axis from the axis,

N: refractive index of the material of the anamorphic lens r1: the curvature at the first cross section at the principal ray passing position of the entrance surface of the anamorphic lens radius r2: the at the principal ray passing position of the exit surface of the anamorphic lens first curvature in one of the cross-sectional radius d: distance between the incident surface and an exit surface at the principal ray passing position of the anamorphic lens
Made to define A by the formula, the value of the A with respect to the axial principal ray A0, the value of the A to the principal ray at the full field angle in the second cross section perpendicular to the array direction of the plurality of line sensors when the maximum value Amax, the, and satisfies the -0.1 ≦ 1- (Amax / A0) ≦ 0.1 following condition.

Claims

A reading unit having a line sensor of multiple, and an imaging optical system for guiding said reading means a light beam from the original, the document by moving the reading means in the direction of arrangement of said plurality of line sensors an image reading apparatus that reads the,
In the arrangement direction, when the width of the light receiving surface of each of the plurality of line sensors is W , and the distance between the centers of adjacent line sensors is L,
W / L ≦ 0.015
Meets the conditions
The imaging optical system includes an anamorphic surface der Ru anamorphic lens at least one surface of the rotationally asymmetric shape with respect to the optical axis,
Wherein the anamorphic surface, curvature definitive perpendicular first cross section in the direction of arrangement of each pixel of said plurality of line sensors is continuously varied toward off-axis from the axis,

N: refractive index r ₁ of the material of the anamorphic lens: the radius of curvature at the at the principal ray passing position of the entrance surface of the anamorphic lens first cross section r _2: at the principal ray passing position of the exit surface of the anamorphic lens said first radius of curvature in the cross section d: distance between the incident surface and an exit surface at the principal ray passing position of the anamorphic lens
Made to define A by the formula, the value of A ₀ of the A with respect to the axial principal ray, a value of the A to the principal ray at the full field angle in the second cross section perpendicular to the array direction of the plurality of line sensors A _{max is} the maximum value of
−0.1 ≦ 1- (A _max / A ₀ ) ≦ 0.1
Image reading apparatus and satisfies the condition that.

The value of A with respect to the chief ray at _50% angle of view in the second cross section is A _50% ,
The value of A with respect to the chief ray at _{70% field} angle in the second cross section is set to A _70% ,
Can and the value of A to the principal ray at 90% angle within said second cross-section A _90%, that,
−0.05 ≦ 1- (A _70% / A _50% ) ≦ 0.05,
−0.08 ≦ 1- (A _90% / A _50% ) ≦ 0.08,
The image reading apparatus according to claim 1, characterized by satisfying the following condition.

The image reading apparatus according to claim 1, wherein the incident surface and the exit surface of the anamorphic lens are anamorphic surfaces having a rotationally asymmetric shape with respect to the optical axis.

4. The curvature of the first cross section and the curvature of the second cross section of the entrance surface and the exit surface of the anamorphic lens are equal on the axis . 5. The image reading apparatus according to item.

The imaging optical system, from the original side in this order, a first lens having a positive refractive power incident surface a convex meniscus shape, aperture, the entrance surface and the exit surface is concave in the second lens, the incident and exit surfaces are a third lens of a convex shape, the fourth lens exit surface of the convex meniscus shape, in the configuration, the anamorphic lens in any one of claims 1 to 4, wherein the Ru said fourth lens der The image reading apparatus described.

The image reading apparatus according to claim 5 wherein the fourth lens is characterized by Tei Rukoto molded by resin.