Micro aspherical lens and fabricating method therefor and optical device

• US 5,148,322 A
• Filed: 11/09/1989
• Issued: 09/15/1992
• Est. Priority Date: 11/09/1989
• Status: Expired due to Term

• Current Assignee: Omron Tateisi Electronics Co. (Omron Corporation)
• Original Assignee: Omron Tateisi Electronics Co. (Omron Corporation)
• Inventors: Aoyama, Shigeru, Ogata, Shiro, Yamashita, Tsukasa
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Lerner, Martin
• Application Number:
  US07/434,029
• Time in Patent Office: 1,041 Days
• Field of Search: 350/432, 350/417, 350/167, 350/413, 350/422, 350/96.2, 369/44.23, 359/619, 359/708, 359/659, 385/50, 250/201.5, 264/1.4, 264/900
• US Class Current: 359/708
• CPC Class Codes: G02B 3/0012 characterised by the manufacturing method
• CPC Class Codes: G02B 3/0031 Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 3/0068 arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements G02B5/1885, G02B17/002, G02B30/27 take precedence
• CPC Class Codes: G02B 3/02 with non-spherical faces G02B3/10 takes precedence
• CPC Class Codes: G03F 7/001 Phase modulating patterns, e.g. refractive index patterns
• CPC Class Codes: Y10S 359/90 Methods

Abstract

An electron-beam resist is applied over a substrate so as to have a thickness larger than the maximum thickness of a micro aspherical lens to be fabricated, a predetermined pattern is written on this resist by electron-beam lithography and then, the resist is developed, thereby to fabricate a micro aspherical lens or the prototype thereof. Consequently, a micro aspherical lens causing little on-axis aberration and chromatic aberration and having a diameter of 1 millimeter or less can be achieved with high precision. In addition, the micro aspherical lens can be produced in large quantity because the reproduction thereof is relatively easy. Furthermore, an optical fiber coupling device, a focusing optical system, an optical device, a semiconductor laser light source, an image device or the like can be constructed using the micro aspherical lens thus fabricated. Finally, a micro lens array constructed by arranging converging lenses having a diameter of approximately several to several hundred micrometers in a two-dimensional manner is used and this micro lens array is arranged ahead of a light source, thereby forming a multi-beam spot caused by diffraction in a distant position. A three-dimensional shape can be recognized with high precision by shape recognition means utilizing this multi-beam spot.

Claims

1. A method of fabricating a micro aspherical lens, comprising the steps of:

applying an electron-beam resist on a substrate on which a micro aspherical lens is to be fabricated so as to have a thickness larger than the maximum thickness of the micro aspherical lens to be fabricated,

writing a predetermined pattern on said resist using an electron-beam lithography system so as to irradiate an electron beam in amounts of irradiation corresponding to the thickness of the micro aspherical lens to be fabricated, and

thereafter developing the resist, thereby to fabricate a micro aspherical lens made of the remaining resist or the prototype thereof.

2. A method of fabricating an aspherical lens or its stamper, comprising the steps of:

applying an electron-beam resist on a first substrate so as to have a thickness larger than the maximum thickness of the micro aspherical lens to be fabricated,

writing a predetermined pattern on said resist using electron-beam lithography so as to irradiate an electron-beam in amounts of irradiation corresponding to the thickness of the micro aspherical lens to be fabricated,

developing the resist to produce a remaining resist having a convex portion in a form of an aspherical lens or a remaining resist having a concave portion of the same shape, and

transferring onto a second substrate said remaining resist by dry etching.

3. A micro aspherical lens fabricated by the method as set forth in claim 2.

4. A method of fabricating a micro aspherical lens, comprising the steps of:

applying an electron-beam resist on a substrate on which a prototype for use in making a stamper is to be fabricated to a thickness which is larger than the maximum thickness of a micro aspherical lens to be fabricated,

writing a predetermined pattern on said resist using an electron-beam lithography system so as to irradiate an electron-beam in amounts of radiation corresponding to the thickness of the micro aspherical lens to be fabricated,

developing the resist to fabricate said prototype from said remaining resist, said remaining resist having a convex portion in the form of an aspherical lens or a concave portion in the form of an aspherical lens to be fabricated, fabricating a stamper utilizing said prototype, and

forming a micro aspherical lens using said stamper.

5. A micro aspherical lens fabricated by the method as set forth in claim 4.

6. A micro aspherical lens fabricated by the steps of:

applying an electron-beam resist on a substrate so as to have a thickness larger than the maximum thickness of the micro aspherical lens to be fabricated,

writing a predetermined pattern on said resist using electron-beam lithography so as to irradiate an electron-beam in amounts of irradiation corresponding to the thickness of the micro aspherical lens,

developing the resist to produce a remaining resist having a convex portion in a form of said micro aspherical lens.