Objective with aspheric surfaces for imaging microzones

• US 4,655,555 A
• Filed: 11/28/1984
• Issued: 04/07/1987
• Est. Priority Date: 12/03/1983
• Status: Expired due to Fees

• Current Assignee: Carl Zeiss Aka Zeiss
• Original Assignee: Carl-Zeiss-Stiftung
• Inventors: Schlemmer, Harry, Machler, Meinrad, Bittner, Reinhold, Gluck, Franz
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Gass, Rebecca D.
• Application Number:
  US06/675,735
• Time in Patent Office: 860 Days
• Field of Search: 350/432, 350/619, 350/504, 350/435
• US Class Current: 359/365
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01N 2021/6469 Cavity, e.g. ellipsoid
• CPC Class Codes: G02B 13/24 for reproducing or copying at short object distances
• CPC Class Codes: G02B 17/008 Systems specially adapted to form image relays or chained systems
• CPC Class Codes: G02B 17/023 for extending or folding an optical path, e.g. delay lines
• CPC Class Codes: G02B 17/0808 on-axis systems with at least one of the mirrors having a central aperture
• CPC Class Codes: G02B 17/086 wherein the system is made of a single block of optical material, e.g. solid catadioptric systems
• CPC Class Codes: G03F 7/70233 Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems

Abstract

The invention is directed to objectives for imaging small regions with a large aperture angle. The objectives include two aspheric bodies made of optically isotropic material wherein the deflection of the light rays is achieved by total reflection on the outer surfaces. The light entry surfaces and light exit surfaces are configured as spherical surfaces having center points at least approximately coincident with the focal points of the aspheric bodies.

Claims

1. An objective comprising:

a plurality of optically isotropic aspheric bodies defining a common optical axis and having respective aspherical outer surfaces and having respective first focal points on said axis;

said aspherical outer surfaces defining respective uncoated reflecting surfaces;

first spherical light passage surface means formed on a first one of said bodies and having a center point at least approximately in coincidence with the first focal point of said first body;

second spherical light passage surface means formed on a second one of said bodies and having a center point at least approximately in coincidence with the first focal point of said second body;

said bodies having respective second focal points also disposed on said axis and being at least approximately in coincidence with each other; and

,

one of said spherical light passage surface means being a light entry surface and the other one of spherical light passage surface means being a light exit surface.

2. The objective of claim 1, said bodies being configured as ellipsoids and said first focal points being outer focal points disposed on said optical axis;

said second focal points being respective inner focal points disposed on said axis.

3. The objective of claim 2, said ellipsoids being directly connected with each other.

4. The objective of claim 2, said ellipsoids having mutually adjacent end faces configured to conjointly define a spherically-shaped air space therebetween having a center;

said inner focal points being at least approximately in coincidence with said center.

5. An objective comprising:

a plurality of optically isotropic aspheric bodies having respective aspherical outer surfaces and having respective focal points;

said aspherical outer surfaces defining respective reflecting surfaces;

first spherical light passage surface means formed on a first one of said bodies and having a center point at least approximately in coincidence with the focal point of said first body;

second spherical light passage surface means formed on a second one of said bodies and having a center point at least approximately in coincidence with the focal point of said second body;

one of said spherical light passage surface means being a light entry surface and the other one of spherical light passage surface means being a light exit surface;

said bodies being configured as ellipsoids and said focal points being outer focal points disposed on an optical axis;

said ellipsoids also having respective inner focal points also disposed on said axis and being at least approximately in coincidence with each other;

said ellipsoids having mutually adjacent end faces configured to conjointly define a spherically-shaped cavity therebetween; and

,

a sphere made of optically isotropic material and disposed in said cavity, said sphere having a center at least approximately in coincidence with said two coincident inner focal points.

6. The objective of claim 5, the material of said sphere being selected so that the latter has a refractive index greater than the refractive index of said ellipsoids.

7. An objective comprising:

a plurality of optically isotropic aspheric bodies defining a common optical axis and having respective aspherical outer surfaces;

said aspherical outer surfaces defining respective uncoated reflecting surfaces;

a first one of said bodies being a paraboloid having an inner focal point and a second one of said bodies being an ellipsoid having an inner focal point and an outer focal point on said axis;

first spherical light passage surface means formed on said paraboloid and having a center point at infinity;

second spherical light passage surface means formed on said ellipsoid and having a center point at least approximately in coincidence with said outer focal point of said ellipsoid;

said inner focal points being in coincidence with each other and located on said axis;

one of said spherical light passage surface means being a light entry surface and the other one of spherical light passage surface means being a light exit surface;

said paraboloid and said ellipsoid having mutually adjacent end faces configured to conjointly define a spherically-shaped cavity therebetween; and

,

a sphere made of optically isotropic material and disposed in said cavity, said sphere having a center at least approximately in coincidence with said two coincident inner focal points.

8. The objective of claim 7, the material of said sphere being selected so that the latter has a refractive index greater than the refractive index of said paraboloid and said ellipsoid.

9. An objective comprising:

a plurality of optically isotropic aspheric bodies defining a common optical axis and having respective aspherical outer surfaces;

said aspherical outer surfaces defining respective uncoated reflecting surfaces;

said bodies being respective paraboloidal portions arranged with respect to said optical axis and having respective focal points on said optical axis;

said paraboloidal portions having respective axes inclined with respect to said optical axis and having respective outer spherical surfaces, said outer spherical surfaces defining respective center points coincident with corresponding ones of said focal points;

said paraboloidal portions having respective inner spherical surfaces;

said inner spherical surfaces having respective center points at infinity; and

,

planar reflecting surface means arranged between said paraboloidal portions for conducting a parallel bundle of rays from the inner spherical reflecting surface of a first one of said paraboloidal portions to the inner reflective surface of a second one of said paraboloidal portions.

10. The objective of claim 9, said planar reflecting surface means being an even number of planar reflecting surfaces arranged so as to cause said bundle of rays to cross upon itself between the first one of said planar reflecting surfaces along the trace of said bundle of rays and the last one of said planar reflecting surfaces along said trace.

11. The objective of claim 10, comprising interference layer means covering at least a portion of said planar reflecting surfaces.

12. An objective for use with optical measuring instruments such as a spectrometer or the like comprising:

a plurality of optically isotropic aspheric bodies defining a common optical axis and having respective aspherical outer surfaces and having respective first focal points on said axis;

said aspherical outer surfaces defining respective uncoated reflecting surfaces;

first spherical light entry surface means formed on a first one of said bodies and having a center point at least approximately in coincidence with the first focal point of said first body;

second spherical light exit surface means formed on a second one of said bodies and having a center point at least approximately in coincidence with the first focal point of said second body; and

,

said bodies having respective second focal points also disposed on said axis and being at least approximately in coincidence with each other.

13. An objective comprising:

a plurality of optically isotropic aspheric bodies defining a common optical axis and having respective aspherical outer surfaces;

said aspherical outer surfaces defining respective uncoated reflecting surfaces;

a first one of said bodies being a paraboloid having an inner focal point and a second one of said bodies being an ellipsoid having an inner focal point and an outer focal point on said axis;

first spherical light passage surface means formed on said paraboloid and having a center point at infinity;

second spherical light passage surface means formed on said ellipsoid and having a center point at least approximately in coincidence with said outer focal point of said ellipsoid;

said inner focal points being in coincidence with each other and located on said axis; and

,

one of said spherical light passage surface means being a light entry surface and the other one of said spherical light passage surface means being a light exit surface.

14. The objective of claim 13, said paraboloid and said ellipsoid being directly connected with each other.

15. The objective of claim 13, said paraboloid and said ellipsoid having mutually adjacent end faces configured to conjointly define a spherically-shaped air space therebetween having a center;

said inner focal points being at least approximately in coincidence with said center.