Illumination optical system, and spectrophotometric apparatus and image forming apparatus including the same

Patent metadata

Field	Value
Publication number	US-10012938-B2
Application number	US-201615347263-A
Country	US
Kind code	B2
Filing date	Nov 9, 2016
Priority date	Nov 11, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

Provided is an illumination optical system includes: a light source; and a light guiding member configured to guide a light flux emitted from the light source to an illuminated surface, the light guiding member having: an incident surface into which the light flux from the light source enters; an ellipsoidal reflection surface configured to reflect the light flux from the incident surface; and an exit surface from which the light flux reflected by the ellipsoidal reflection surface exits, in which the light source is arranged so as to be separated from a first focal point of the ellipsoidal reflection surface at a position farther from the illuminated surface, in a direction perpendicular to a light emitting surface of the light source.

First claim

What is claimed is:

1. An illumination optical system, comprising:
a light source; and
a light guiding member configured to guide a light flux emitted from the light source to an illuminated surface,
the light guiding member having:
an incident surface into which the light flux from the light source enters;
an ellipsoidal reflection surface configured to reflect the light flux from the incident surface; and
an exit surface from which the light flux reflected by the ellipsoidal reflection surface exits,

wherein the light source is arranged so as to be separated from a first focal point of the ellipsoidal reflection surface at a position farther from the illuminated surface, in a direction perpendicular to a light emitting surface of the light source.

2. An illumination optical system according to claim 1 , wherein the light emitting surface of the light source is arranged close to the incident surface of the light guiding member.

3. An illumination optical system according to claim 1 , wherein, when a direction including two focal points of a spheroid defining the ellipsoidal reflection surface is defined as a z-axis, an intersection of the spheroid with the z-axis is defined as an origin, two directions that are orthogonal to the z-axis and perpendicular to each other are defined as an x-axis and a y-axis, and a surface shape of the spheroid is defined as:

Z
=

(

x
2

+

y
2

)

R

1
+

1
-

(

1
+
k

)

⁢

x
2

+

y
2

R
2

and when Δ max is set as follows:

Δ

ma
⁢

⁢
x

=

R

1
+

1
-

(

k
+
1

)

⁢
cos
⁢

⁢
θ

where R represents a curvature radius of the spheroid at the origin, k represents a conic constant, and θ represents an angle formed between the z-axis and a direction perpendicular to the light emitting surface of the light source,
the light source is arranged so as to be separated by a distance Δ satisfying:
0.1Δ max ≤Δ≤0.5Δ max

from the first focal point of the ellipsoidal reflection surface in the direction perpendicular to the light emitting surface of the light source.

4. An illumination optical system according to claim 1 , wherein, when a direction including two focal points of a spheroid defining the ellipsoidal reflection surface is defined as a z-axis, an intersection of the spheroid with the z-axis is defined as an origin, two directions that are orthogonal to the z-axis and perpendicular to each other are defined as an x-axis and a y-axis, and a surface shape of the spheroid is defined as:

Z
=

(

x
2

+

y
2

)

R

1
+

1
-

(

1
+
k

)

⁢

x
2

+

y
2

R
2

and when Δ max is set as follows:

Δ

ma
⁢

⁢
x

=

R

1
+

1
-

(

k
+
1

)

⁢
cos
⁢

⁢
θ

Assignees

• Canon Kk

Inventors

• Miyajima Yu

Classifications

• F21Y2115/15

  Organic light-emitting diodes [OLED] · CPC title

• G03G2215/0145

  the linear arrangement being vertical · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• G03G15/50 Primary

  Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control (sequencing control G03G21/14) · CPC title

• G03G15/5062 Primary

  by measuring the characteristics of an image on the copy material · CPC title