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Diffractive optical element, optical system and optical apparatus

A technology of diffractive optical elements and optical systems, applied in the field of diffractive optical elements, can solve the problems of not being high enough, the degradation of diffraction efficiency, etc., and achieve high diffraction efficiency and the effect of suppressing unnecessary diffracted light

Active Publication Date: 2008-09-24
CANON KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0019] Meanwhile, in the case of the contact double-layer DOE disclosed in the above-mentioned Japanese Patent Application Laid-Open Publication No. 2005-107298 and Japanese Patent Application Laid-Open Publication No. 2003-227913, the performance of this diffractive optical element itself, particularly as a design The diffraction efficiency of the first-order diffracted light of the diffracted order light is about 95 to 97% over the entire use wavelength range, which is not high enough
In other words, glare due to unwanted diffracted light can cause problems
Also, since the contact two-layer DOE disclosed in the above-mentioned Japanese Patent Application Laid-Open Publication No. 2005-107298 includes a thick grating as thick as about 20 μm or more, there is a problem of deterioration in diffraction efficiency caused by vignetting of oblique incident rays. another question

Method used

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  • Diffractive optical element, optical system and optical apparatus
  • Diffractive optical element, optical system and optical apparatus
  • Diffractive optical element, optical system and optical apparatus

Examples

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Embodiment 1

[0093] FIG. 1 is a front view (left diagram) and a side view (right diagram) of a diffractive optical element as an example (Example 1) of the present invention. In FIG. 1, the character O represents the central axis of the diffractive optical element. figure 2 It is a partially enlarged view showing the diffractive optical element of FIG. 1 in a cross section taken along the line A-A' of FIG. 1 . It should be noted here that figure 2 Not drawn to scale along raster depth.

[0094] As shown in these drawings, the diffractive optical element 10 includes a first element portion 12 and a second element portion 13 . The first element part 12 includes a first transparent substrate 14 and a first grating forming layer composed of a grating base 16 provided on the first transparent substrate 14 and a first diffraction grating 18 integrally formed with the grating base 16 . The second element part 13 includes a second transparent substrate 15 and a second grating forming layer co...

Embodiment 2

[0136] Embodiment 2 of the present invention will be described below. The diffractive optical element of this embodiment has basically the same configuration as that of Embodiment 1. That is, elements with Figure 1 and figure 2 structure shown. Therefore, the same reference numerals are assigned to components common to Embodiment 1, their detailed explanation will be omitted, and the following description will focus on the differences.

[0137] In the diffractive optical element 10 of this embodiment, figure 2 The first diffraction grating 18 shown is made of acrylic resin and ZrO 2 Particles are made of mixed material (nd=1.611, vd=45.5). The second diffraction grating 19 is made of a mixed material (nd=1.567, vd=21.7) of acrylic resin and ITO particles. The same grating thickness d of the first and second diffraction gratings 18 and 19 is 13.3 µm.

[0138] Figure 5A The diffraction efficiency of the first-order diffracted light in the diffractive optical element 10...

Embodiment 3

[0141] Embodiment 3 of the present invention will be described below. The diffractive optical element of this embodiment has basically the same configuration as that of Embodiment 1. That is, elements with Figure 1 and figure 2 structure shown. Therefore, the same reference numerals are assigned to components common to Embodiment 1, their detailed explanation will be omitted, and the following description will focus on the differences.

[0142] In the diffractive optical element 10 of this embodiment, figure 2 The first diffraction grating 18 shown is made of acrylic resin and Al 2 o 3 Particles are made of mixed material (nd=1.594, vd=58.0). The second diffraction grating 19 is made of a mixed material (nd=1.519, vd=16.5) of fluororesin and ITO particles. The same grating thickness d of the first and second diffraction gratings 18 and 19 is 7.8 µm.

[0143] Figure 6A The diffraction efficiency of the first-order diffracted light in the diffractive optical element 1...

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Abstract

The diffractive optical element includes two diffraction gratings made of different materials and being in contact with each other at their grating surfaces. The materials satisfy the following conditions, and the second material is obtained by mixing a resin material with a particulate material satisfying the following conditions: nd1 1.48, 1 / 2 d1 40, (-1.665E-07 1 / 2 d1 3 +5 .213E-05 1 / 2 d1 2 -5.656E-03 1 / 2 d1+0.675) 6g,F1 (-1.665E-07 1 / 2 d1 3 +5.21 3E-05 1 / 2 d1 2 -5.656E-03 1 / 2 d1+0.825), (-1.687E-07 1 / 2 d1 3 +5.702E-05 1 / 2 d1 2 -6.603E-03 1 / 2 d1+1.400) g, d1 (-1.687E-07 1 / 2 d1 3 +5.702E-05 1 / 2 d1 2 -6.603E-03 1 / 2 d1+1.580), nd2 1.6,vd2 30, g,F2 (-1.665E-07 1 / 2 d2 3 +5.213E-05 1 / 2 d2 2 -5.6 56E-03 1 / 2 d2+0.675), g,d2 (-1.687E-07 1 / 2 d2 3 +5.702E-05 1 / 2 d2 2 -6.603E-03 1 / 2 d2+1.400), nd1-nd2>0, ndb2 1.70, vdb2 20. The element achieves a high diffraction efficiency in a specific diffraction order over a wide wavelength range.

Description

technical field [0001] The present invention relates to a diffractive optical element used in optical systems and optical devices, and more particularly, to a diffractive optical element configured such that diffraction gratings made of two materials are in contact with each other. Background technique [0002] There are methods of reducing chromatic aberration through the combination of glass materials. On the other hand, in SPIE Vol.1354 International Lens Design Conference (1990), Japanese Patent Application Laid-Open Publication No. 4(1992)-213421, Japanese Patent Application Laid-Open Publication No. 6(1994)-324626 and U.S. Patent No. 5,044,706 Other methods of reducing chromatic aberration by providing a diffractive optical element having a diffractive function (hereinafter may be referred to as a diffraction grating) on ​​a lens surface or as a part of an optical system are disclosed. This method utilizes the physical phenomenon that chromatic aberration occurs in op...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B5/18
Inventor 安井裕人
Owner CANON KK