Multilayer diffractive optical element

Patent metadata

Field	Value
Publication number	US-2016077251-A1
Application number	US-201514850804-A
Country	US
Kind code	A1
Filing date	Sep 10, 2015
Priority date	Sep 12, 2014
Publication date	Mar 17, 2016
Grant date	—

Abstract

A multilayer diffractive optical element includes a first substrate, a second substrate, a first resin layer having a first diffraction grating pattern and interposed between the first substrate and the second substrate, and a second resin layer having a second diffraction grating pattern and interposed between the first substrate and the second substrate. The first resin layer includes a first region provided at a peripheral portion adjacent to a portion of the first diffraction grating pattern. The first resin layer includes a second region provided at a peripheral portion adjacent to the first region.

First claim

What is claimed is:

1 . A multilayer diffractive optical element,
comprising: a first substrate; a second substrate; a first resin layer having a first diffraction grating pattern and interposed between the first substrate and the second substrate; and a second resin layer having a second diffraction grating pattern and interposed between the first substrate and the second substrate, wherein the first resin layer includes a first region provided at a peripheral portion adjacent to a portion of the first diffraction grating pattern, the first region satisfying 1<h/hd, wherein h represents a thickness of the first resin layer in a direction normal to a surface of the first substrate, and hd represents an average grating height of the first diffraction grating pattern, wherein the first resin layer includes a second region provided at a peripheral portion adjacent to the first region, the second region satisfying h/h 1 <0.34, wherein h 1 represents an average thickness of the first region, and wherein Expression (1) below is satisfied,
50≦ w 1/ hd and 0.5≦ w 2/ w 1  (1),

wherein w 1 represents a width of the first region in a radial direction along a plane parallel to the surface of the first substrate, and w 2 represents a width of the second region in the radial direction along a plane parallel to the surface of the first substrate.

2 . The multilayer diffractive optical element according to claim 1 ,
wherein the first region satisfies 1≦h/hd≦1.4 and 50≦w 1 /hd≦160, and wherein the second region satisfies 0.04≦h/h 1 ≦0.34 and 0.5≦w 2 /w 1 ≦1.

3 . The multilayer diffractive optical element according to claim 1 ,
wherein the multilayer diffractive optical element is an optical lens.

4 . The multilayer diffractive optical element according to claim 1 ,
wherein one of the first resin layer and the second resin layer includes an indium tin oxide fine particle.

5 . The multilayer diffractive optical element according to claim 1 ,
wherein the first resin layer has an average thickness of greater than 1 μm and less than 3 μm at a portion other than the first diffraction grating pattern, and includes an indium tin oxide particle dispersed therein, the indium tin oxide particle having a number-average particle size of greater than 1 nm and less than 100 nm.

6 . The multilayer diffractive optical element according to claim 1 ,
wherein the first resin layer has a refractive index of no less than 1.54 and no greater than 1.63 and an Abbe number of no less than 42 and no greater than 57, and wherein the second resin layer has a refractive index of no less than 1.48 and no greater than 1.57 and an Abbe number of no less than 14 and no greater than 28.

Assignees

• Canon Kk

Inventors

• Genda Hideo
• Niwa Maiko

Classifications

• G02B5/1866 Primary

  Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials (G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence) · CPC title

• G02B5/1895

  such optical elements having dioptric power · CPC title

• G02B5/1857

  using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams · CPC title

• G02B5/189

  Structurally combined with optical elements not having diffractive power · CPC title

• B29D11/00269

  Fresnel lenses · CPC title