Projection display having kohler illumination of projection lenses

• US 8,777,424 B2
• Filed: 06/11/2010
• Issued: 07/15/2014
• Est. Priority Date: 06/15/2009
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Schreiber, Peter, Sieler, Marcel, Foerster, Erik
• Primary Examiner(s): Epps, Georgia Y
• Assistant Examiner(s): Reilly-Diakun, Jori S
• Application Number:
  US12/998,045
• Publication Number:
  US 20110228231A1
• Time in Patent Office: 1,495 Days
• Field of Search: 353 30- 33, 353/38, 353/94, 353/100, 353/102, 353/122, 359/618, 359649-651, 359/676, 359/741, 359/786, 359796-797
• US Class Current: 353/94
• 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: G03B 21/13 Projectors for producing special effects at the edges of picture, e.g. blurring
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026

Abstract

A projection display having at least one light source and also regularly-disposed optical channels. The optical channels comprise at least one field lens, to which respectively one object structure to be imaged and also at least one projection lens are assigned. The distance of the projection lenses from the assigned object structures corresponds to the focal distance of the projection lenses while the distance of the object structures to be imaged from the assigned field lens is chosen such that a Köhler illumination of the assigned projection lens is made possible. Then the individual projections are superimposed to form the total image.

Claims

1. A projection display having at least one light source and regularly-disposed optical channels, each comprising at least one field lens, to each of which one object structure to be imaged and at least one projection lens are assigned, wherein for each regularly-disposed optical channel the distance from the at least one projection lens to the object structure corresponds to the focal distance of the projection lens and the distance from the identical object structure to the at least one field lens is chosen such that a Kö

hler illumination of the at least one projection lens is made possible, and wherein the at least one projection lenses assigned to the regularly-disposed optical channels produce individual projections which are superimposed to form an actual total picture on a screen or a virtual total picture.

2. A projection display according to claim 1, wherein each of the optical channels has a further common field lens for compensating for the illumination telecentricity.

3. A projection display according to claim 1, wherein each of the optical channels have optical elements adapted with respect to the channels, the optical elements comprising concentrators for masking the inactive regions between the field lenses.

4. A projection display according to claim 1, wherein each of the object structures have a predistortion, with respect to the channels, for correction of a distortion.

5. A projection display according to claim 1, wherein the projection lenses remote from an optical axis of a central optical channel have a greater focal distance for correction of a lack of focus due to the larger image distance of these channels.

6. A projection display according to claim 5, wherein the projection lenses remote from an optical axis of a central optical channel are adapted, with respect to sagittal and tangential focal distance, by being designed as anamorphotic lenses, with respect to the channels, for compensation of astigmatism.

7. A projection display according to claim 1, wherein said at least one optical channel has at least two projection lenses for aberration correction.

8. A projection display according to claim 1, wherein said at least a part of the optical channels have object structures buried below the field lenses in the form of a lithographically-structured object mask.

9. A projection display according to claim 1, wherein the object structures are disposed at least partially on a curved surface comprising at least a surface of the associated at least one field lens in order to level out the image field.

10. A projection display according to claim 1, wherein the projection display has a constructional length in the range of 0.5 to 10 mm.

11. A projection display according to claim 1, wherein the projection lenses have a reduced average distance relative to the object structures, as a result of which the optical axes of the outer optical channels are tilted.

12. A projection display according to claim 1, wherein the projection display is subdivided into three segments which are assigned respectively to a primary color part, as a result of which a full color projection is made possible.

13. A projection display according to claim 12, wherein the number of lenses assigned to the respective primary color and object structures is chosen such that a white balance which compensates for the spectral properties of the source or of the source and a plurality of color filters is made possible with simultaneous maximization of the image brightness.

14. A projection display according to claim 1, wherein the object structure is produced by a digital imager comprising an LCD display or an OLED display.

15. A projection display according to claim 1, wherein the projection display has a unit for electronic offset of the individual images, as a result of which a projection distance is controlled.

16. A projection display according to claim 15, wherein the projection display has a unit for measuring the distance from the screen, which, in combination with the unit for the electronic offset, enables electronic tracking of the projection distance.