Optical multilayer structure, optical switching device, and image display

• US 20050219680A1
• Filed: 05/24/2005
• Published: 10/06/2005
• Est. Priority Date: 07/03/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ishikawa, Hiroichi
• Granted Patent: US 7,012,734 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 5/284 of etalon type comprising a resonant cavity other than a thin solid film, e.g. gas, air, solid plates etalons for fibre optic multiplexing G02B6/29358; etalons for spectral measurement G01J3/26
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361
• CPC Class Codes: G02B 5/286 having four or fewer layers, e.g. for achieving a colour effect
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3524 the optical element being refractive
• CPC Class Codes: G02B 6/3544 2D constellations, i.e. with switching elements and switched beams located in a plane
• CPC Class Codes: G02B 6/355 1x2 switch, i.e. one input and a selectable single output of two possible outputs
• CPC Class Codes: G02B 6/3572 Magnetic force magnetic forces controlling reflecting elements in general G02B26/085; magneto-optic devices G02F1/09
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 6/3594 Characterised by additional functional means, e.g. means for variably attenuating or branching or means for switching differently polarized beams

Abstract

An optical multilayer structure has a substrate, a light-absorbing first layer in contact with the substrate, a gap portion having a changeable size capable of causing an optical interference phenomenon, and a second layer. By changing the size of the gap portion, an amount of reflection, transmission, or absorption of incident light can be changed. For example, the substrate is made of carbon (C), the first layer is made of tantalum (Ta), and the second layer is made of silicon nitride (Si₃N₄). Also in a visible light area, high response is realized. Consequently, the optical multilayer structure can be suitably used for an image display. The optical multilayer structure may be obtained by stacking, on a substrate made of a metal such as chromium (Cr), a first transparent layer made of a material having a high refractive index such as TiO₂ (n=2.40), a second transparent layer made of a material having a low refractive index such as MgF₂ (n=1.38), a gap portion having a changeable size capable of causing an optical interference phenomenon, and a third transparent layer made of a material having a high refractive index such as TiO₂.

Claims

1-58. -58. (canceled)

59. An optical multilayer structure comprising:

a transparent substrate made of a non-metallic material;

a first transparent layer in contact with the transparent substrate;

a gap portion having a changeable size capable of causing an optical interference phenomenon; and

a second transparent layer,

the first transparent layer, the gap portion, and the second transparent layers being stacked in accordance with this order on the transparent substrate,

wherein when a refractive index of the transparent substrate is n_s, a refractive index of the first transparent layer is n₁, and a refractive index of the second transparent layer is n₂, the relation of n_s<

n₁, and the relation of n₁>

n₂ are satisfied.

60. An optical multilayer structure according to claim 59, further comprising driving means for changing an optical size of the gap portion,

wherein the size of the gap portion is changed by the driving means, thereby changing an amount of reflection or absorption of incident light entered from the transparent substrate side or a side opposite to the transparent substrate.

61. An optical multilayer structure according to claim 60, wherein an optical thickness of the first and second transparent layers is λ

/4 or an odd multiple of λ

/4 (λ

;

wavelength of incident light).

62. An optical multilayer structure according to claim 61, wherein the optical size of the gap portion is changed by the driving means in a binary manner or continuously between an odd multiple of λ

/4 and an even multiple of λ

/4 (including

     0), thereby changing the amount of reflection or transmission of incident light in a binary manner or continuously.

63. An optical multilayer structure according to claim 59, wherein the value of n₂ is n₁/{square root}{square root over ( )}n_s.

67. An optical multilayer structure according to claim 59, wherein the gap portion is filled with air, transparent gas, or transparent liquid.

68. An optical multilayer structure according to claim 67, wherein the gap portion is filled with a liquid, and functions as a layer having a low refractive index, an intermediate refractive index, or a high refractive index.

69. An optical multilayer structure according to claim 59, wherein the gap portion is in vacuum.

70. An optical multilayer structure according to claim 60, wherein the driving means changes an optical size of the gap portion by using a magnetic force.

71-78. -78. (canceled)

79. An optical switching device comprising:

an optical multilayer structure having a transparent substrate made of a non-metallic material, a first transparent layer, a gap portion having a changeable size capable of causing an optical interference phenomenon, and a second transparent layer, the first transparent layer, the gap portion, and second transparent layer being stacked in accordance with this order on the transparent substrate; and

driving means for changing an optical size of the gap portion,

wherein when a refractive index of the transparent substrate is n_s, a refractive index of the first transparent layer is n₁, and a refractive index of the second transparent layer is n₂, the relation of n_s<

n₁, and the relation of n₁>

n₂ are satisfied.

80. (canceled)

81. An image display for displaying a two-dimensional image by irradiating a plurality of optical switching devices arranged one-dimensionally or two-dimensionally with light,

the optical switching device comprising:

an optical multilayer structure having a transparent substrate made of a non-metallic material, a first transparent layer, a gap portion having a changeable size capable of causing an optical interference phenomenon, and a second transparent layer, the first transparent layer, the gap portion, and the second transparent layer being stacked in accordance with this order on the transparent substrate; and

driving means for changing an optical size of the gap portion,

wherein when a refractive index of the transparent substrate is n_s, a refractive index of the first transparent layer is n₁, and a refractive index of the second transparent layer is n₂, the relation of n_s<

n₁ and the relation of n₁>

n₂ are satisfied.

82. (canceled)