Invention concerning a condensor lens

• US 20050286145A1
• Filed: 10/15/2004
• Published: 12/29/2005
• Est. Priority Date: 06/25/2004
• Status: Abandoned Application

• Current Assignee: VSWARCO FUTURIT Verkehrssignalsysteme Ges.m.b.H.
• Original Assignee: VSWARCO FUTURIT Verkehrssignalsysteme Ges.m.b.H.
• Inventors: Di Otto, Alexander, Silhengst, Franz
• Application Number:
  US10/966,938
• Publication Number:
  US 20050286145A1
• Time in Patent Office: Days
• US Class Current: 359/742
• CPC Class Codes: F21V 23/003 the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array
• CPC Class Codes: F21V 5/045 the lens having discontinuous faces, e.g. Fresnel lenses
• CPC Class Codes: F21V 5/048 the lens being a simple lens adapted to cooperate with a point-like source for emitting mainly in one direction and having an axis coincident with the main light transmission direction, e.g. convergent or divergent lenses, plano-concave or plano-convex lenses
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 17/006 Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses Fresnel mirrors G02B5/09, Fresnel lenses G02B3/08

Abstract

A condenser lens for generation of essentially parallel light beams, in which the condenser lens (8) curves essentially in the form of a shell around its focal point (F) and has, at least in one region (27) on the inside (20) of the shell, a Fresnel structure in the form of teeth (16) that are bounded by light inlet surfaces (14) and reflection surfaces (15). In the region (27), the outside (21) of the shell has gradations formed from outlet surfaces (18) and connecting surfaces (19), in which the outlet surfaces (18) are aligned essentially normal and the connecting surfaces (19) that join the adjacent outlet surfaces (18) are aligned essentially parallel to the optical axis (2). The slope and position of the reflection surfaces (15) of teeth (16) are established, so that an imaginary boundary light beam (6a), coming from focal point (F) and touching the tooth edge (22) of the preceding tooth, touches the indentation base (23) after refraction on the inlet surfaces (14) or encounters the reflection surface (15) in its immediate vicinity and runs parallel to the optical axis (2) after its reflection.

Claims

1. Condenser lens for production of essentially parallel light beams, in which the condenser lens (8) curves essentially in the form of a shell about its focal point (F) and has, at least in a region (27) on the inside (20) of the shell, a Fresnel structure in the form of teeth (16) that are bounded by light entry surfaces (14) and reflection surfaces (15), characterized by the fact that, in region (27), the outside (21) of the shell has gradations formed from outlet surfaces (18) and connection surfaces (19), the outlet surfaces (18) being aligned essentially normal and the connecting surfaces (19) that connect the adjacent outlet surfaces (18) being aligned essentially parallel to optical axis (2).

2. Condenser lens according to claim 1, characterized by the fact that by the arrangement and slope of the reflection surface (15) of a Fresnel tooth (16), an imaginary boundary light beam (6a) issuing from focal point (F) and touching the tooth edge (22) of the preceding tooth (16″

), after refraction on the inlet surface (14), touches the indentation base (23) or strikes the reflection surface (15) in its immediate vicinity and runs parallel to optical axis (2) after reflection.

3. Condenser lens according to claim 1, characterized by the fact that the light inlet surfaces (14) of tooth (16) are aligned parallel to optical axis (2).

4. Condenser lens according to claim 1, characterized by the fact that for each gradation (18, 19) on outside (21), at least one tooth (16) of the Fresnel structure is provided on the inside (20).

5. Condenser lens according to claim 1, characterized by the fact that the connecting surfaces (19) and the light entry surfaces (14) are flush with each other.

6. Condenser lens according to claim 1, characterized by the fact that the stepped inside edges (25), formed by the outlet surfaces (18) and the connecting surfaces (19), and the indentation bases (23), formed by the light entry surfaces (14) and reflection surfaces (15), each lie on a limitation surface (29, 30), the limitation surfaces (29, 30) being essentially parallel to each other.

7. Condenser lens according to claim 1, characterized by the fact that the stepped outside edges (24), formed by the outlet surfaces (18) and connection surfaces (19), and the tooth edges (22), formed by the light entry surfaces (14) and reflection surfaces (15), each lie on an envelope surface (26, 28), the envelope surfaces (26, 28) being essentially parallel to each other.

8. Condenser lens according to claim 6, characterized by the fact that the distance between the envelope surface (26) and the limitation surfaces (29) is less than or equal to the distance between the two limitation surfaces (29, 30).

9. Condenser lens according to claim 6, characterized by the fact that the distance between two adjacent indentation bases (23) is less than or equal to the distance between the two limitation surfaces (29, 30).

10. Condenser lens according to claim 1, characterized by the fact that the curvature of the condenser lens (8) diminishes in region (27) toward the edge of condenser lens (8).

11. Condenser lens according to claim 1, characterized by the fact that on at least one light inlet surfaces (14) and/or at least one outlet surface (18), an optical structure, like a lens, for example, a converging lens or a diverging lens, prisms, a knurled surface, etc., are provided for further light guidance.

12. Condenser lens according to claim 1, characterized by the fact that the condenser lens (8) is rotationally symmetrical relative to optical axis (2).

13. Condenser lens according to claim 1, characterized by the fact that it is formed from transparent plastic.

14. Light for generation of essentially parallel light beams, in which the light includes at least one preferably point-like light source (5), for example, an LED, and a condenser lens (8), in which the light sources (5) is arranged at least close to focal point (F) of condenser lens (8), and in which the condenser lens (8) curves essentially in the form of a shell about focal point (F) and has a Fresnel structure in the form of teeth (16) that are bounded by the light inlet surfaces (14) and reflection surfaces (15), at least in one region (27) on the inside (20) of the shell, characterized by the fact that in region (27) the outside (21) of the shell has gradations formed by outlet surfaces (18) and connecting surfaces (19), the outlet surfaces (18) being aligned essentially normal and the connection surfaces (19) that connect the adjacent outlet surfaces (18) being aligned essentially parallel to the optical axis (2).

15. Light according to claim 14, characterized by the fact that by the position and slope of the reflection surfaces (15) of a Fresnel tooth (16), a boundary light beam (6a), coming from the focal point (F) and touching the tooth edge (22) of the preceding tooth, after refraction on inlet surface (14), touches the indentation base (23) or encounters the reflection surface (15) in its immediate vicinity and runs parallel to the optical axis (2) after reflection.

16. Light according to claim 14, characterized by the fact that the light source (5) sits on a bottom (9a) of a housing (9), in which a transparent cover (11) is provided for housing (9), and that the edge of the condenser lens (8) is arranged between housing (9) and cover (11), preferably in the region, in which housing (9) and cover (11) are in contact with each other.

17. Light according to claim 16, characterized by the fact that the cover (11) is fastened to housing (9) by means of a flange connection (12).

18. Light according to claim 16, characterized by the fact that the housing (9) tapers toward bottom (9a).

19. Light according to claim 18, characterized by the fact that the bottom (9a) is flat.

20. Light according to claim 16, characterized by the fact that the cross section defined by the outer edge of condenser lens (8) has essentially the same shape and size as the cross section defined by the edge of cover (11).

21. Light according to claim 16, characterized by the fact that optical elements, for example, a diverging lens, a converging lens, knurling, prisms, etc., are integrated in the cover (11).

22. Light according to claim 16, characterized by the fact that a cooling plate (10) for heat removal is provided beneath light source (5).