Diffusing plate having microlens array

Patent metadata

Field	Value
Publication number	US-9557451-B2
Application number	US-201414309759-A
Country	US
Kind code	B2
Filing date	Jun 19, 2014
Priority date	Jun 21, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A diffusing plate includes a microlens array in which a plurality of microlenses are arranged, wherein the microlenses have such a shape that a curvature of a sectional shape including a center line of the microlenses varies depending on a direction of the center line, and wherein microlenses that are different in the direction of a center line where the curvature of the outline is largest are arranged.

First claim

What is claimed is:

1. A diffusing plate comprising:
a microlens array in which a plurality of rows of microlenses are arranged adjacent to each other,
wherein the microlenses have such a shape that a curvature of a sectional shape including a center line going through a center of each microlens, which is a vertex and shows a highest position of the microlens, varies depending on a direction of the center line, and
wherein, in the microlens array, the direction of a center line of each microlens where the curvature of the sectional shape is largest is different from a direction parallel to the row and different from a direction perpendicular to the row.

2. The diffusing plate having a microlens array according to claim 1 , wherein the microlenses have two parts higher than a spherical shape and two parts lower than the spherical shape at positions axisymmetrical to the highest position of each microlens.

3. The diffusing plate having a microlens array according to claim 2 , wherein the direction of the center line where the curvature of the sectional shape is largest differs from one row to another.

4. The diffusing plate having a microlens array according to claim 2 , wherein the microlenses arranged in each row differ from one another in the direction of the center line where the curvature of an outline is largest.

5. The diffusing plate having a microlens array according to claim 1 , wherein a Fresnel lens is formed on a side different from a side on which the microlens array is formed.

6. A diffusing plate comprising:
a microlens array in which a plurality of microlenses are arranged,
wherein the microlenses have such a shape that a curvature of a sectional shape including a center line going through a center of each microlens, which is a vertex and shows a highest position of the microlens, varies depending on a direction of the center line, and
wherein microlenses that are arranged next to each other in a row differ in the direction of a center line where the curvature of the sectional shape is largest, and
wherein the vertices of the microlenses are arranged spirally.

7. The diffusing plate having a microlens array according to claim 6 , wherein vertices of the microlenses are arranged on a curve defined by R =aθ 0.5 which is a parabolic spiral.

8. The diffusing plate having a microlens array according to claim 5 , wherein the microlenses have two parts higher than a spherical shape and two parts lower than the spherical shape formed at axisymmetrical positions with respect to the vertex.

Assignees

• Canon Kk

Inventors

• Koyama Masatsugu
• Kojima Makoto
• Enokida Yukiya
• Okura Yukinobu
• Tanaka Masato

Classifications

• G02B5/0221 Primary

  the surface having an irregular structure (G02B5/0226 takes precedence) · CPC title

• G02B5/0278

  used in transmission · CPC title

• G02B5/0268

  characterized by the fabrication or manufacturing method · CPC title

• G02B27/16

  used as aids for focusing · CPC title