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CN-116134368-B - Projection with extended illumination area

CN116134368BCN 116134368 BCN116134368 BCN 116134368BCN-116134368-B

Abstract

Projection is performed to expand the illumination area. An optical device (1) comprises an imaging system (2) provided to generate a plurality of images distributed over an imaging plane (3). It further comprises a microlens array MLA (9), wherein microlenses are assigned to the individual images (4) and are provided to form a beam channel (12) by projecting the individual images (4) towards a projection plane (13). The optical expander (17) is arranged between the MLA (9) and the projection plane (13) and comprises an input surface (22) and at least two output surfaces (23,26,33). An optical expander (17) is provided to fan out and direct the beam path (12) onto the projection plane (13) such that individual projections (14) of the individual images (4) are formed on the projection plane (13). An integral projection (15) is formed on the projection plane (13) by superimposing individual projections (14).

Inventors

  • CAO YIYU

Assignees

  • 艾迈斯-欧司朗亚太私人有限公司

Dates

Publication Date
20260505
Application Date
20211006
Priority Date
20201015

Claims (14)

  1. 1. An optical device (1) comprising: an imaging system (2) provided to generate a plurality of images (4) distributed over an imaging plane (3), A microlens array MLA (9), wherein microlenses (8) of the MLA (9) are assigned to respective individual images (4) of the plurality of images and are provided to form respective beam channels (12) by projecting the respective individual images (4) towards a projection plane (13), -An optical expander (17) arranged between the MLA (9) and the projection plane (13), the optical expander (17) comprising an input surface (22) facing the MLA (9) and at least two output surfaces (23,26,33) facing the projection plane (13), the optical expander (17) being provided to fan out and direct the beam channel (12) onto the projection plane (13) such that -Forming an individual projection (14) of the individual image (4) on the projection plane (13) by means of the beam channel (12) directed onto the projection plane (13), and Forming an integral projection (15) on the projection plane (13) by at least partially superimposing the individual projections (14), Wherein the optical expander (17) is arranged such that -The first output surface (23) of the optical expander (17) is provided to direct a first subset (24) of beam channels (12) to a first sub-area (25) of the projection plane (13), and -The second output surface (26) of the optical expander (17) is provided to direct a second subset (27) of beam channels (12) to a second sub-area (28) of the projection plane (13).
  2. 2. The optical device (1) according to claim 1, wherein the optical expander (17) is arranged such that the input surface (22) is parallel to the imaging plane (3) and receives the beam channel (12) from the MLA (9).
  3. 3. Optical device (1) according to claim 1 or 2, wherein the optical expander (17) comprises at least one further output surface (33), the at least one further output surface (33) being provided to direct a further subset (34) of beam channels (12) to a further sub-region (35) of the projection plane (13).
  4. 4. The optical device (1) according to claim 1 or 2, wherein at least one of the output surfaces (23,26,33) of the optical expander (17) is provided to direct a respective subset (24,27,34) of the beam channels (12) by beam refraction at the respective output surface (23,26,33).
  5. 5. The optical device (1) according to claim 1, wherein the optical expander (17) comprises a further surface (36) enabling total internal reflection of the light beam within a portion (37, 38) of the optical expander (17) such that at least one of the subsets (24,27,34) of light beam channels (12) is deflected within the portion (37, 38) of the optical expander (17).
  6. 6. The optical device (1) according to claim 1 or 2, wherein at least one of the output surfaces (23,26,33) of the optical expander (17) is inclined with respect to the input surface (22) of the optical expander (17).
  7. 7. The optical device (1) according to claim 1 or 2, wherein at least two of the output surfaces (23,26,33) of the optical expander (17) are inclined with respect to each other.
  8. 8. The optical device (1) according to claim 1, wherein the optical expander (17) is provided for expanding an illumination zone such that the overall projection (15) on the projection plane (13) is larger than the individual projection (14) on one of the sub-areas (25,28,35) of the projection plane (13).
  9. 9. The optical device (1) according to claim 1 or 2, wherein the imaging system (2) comprises a pattern mask (5) arranged in the imaging plane (3), the pattern mask (5) providing individual images (4) distributed over the imaging plane (3).
  10. 10. The optical device (1) according to claim 1 or 2, wherein the imaging system (2) comprises: A light source (40) provided to display the plurality of images (4), -A collimator lens (42), and/or A condenser lens or condenser lens array (43), The collimator lens (42) and the condenser lens or condenser lens array (43) are provided to form a beam path of the light source (40).
  11. 11. The optical device (1) according to claim 1 or 2, wherein the MLA (9) further comprises a substrate (44), the substrate (44) having a main extension plane parallel to the imaging plane (3) and comprising a rear side (46) facing the imaging plane (3) and a top side (45) facing the optical expander (17), wherein the micro lenses (8) of the MLA (9) are arranged on the top side (45) of the substrate (44).
  12. 12. The optical device (1) according to claim 1 or 2, wherein the projection plane (13) is inclined with respect to the imaging plane (3), or wherein the projection plane (13) is a free-form surface.
  13. 13. An optical device (48) comprising an optical apparatus (1) according to any one of claims 1-12, wherein the optical device (48) is an illuminator or a projector.
  14. 14. A method for forming an integral projection (15), the method comprising: Generating a plurality of images distributed over an imaging plane (3), Assigning microlenses (8) of a microlens array MLA (9) to respective individual images (4) of the plurality of images and forming respective beam channels (12) by projecting the respective individual images (4) towards a projection plane (13), -Providing an optical expander (17) and arranging the optical expander (17) between the MLA (9) and the projection plane (13), the optical expander (17) comprising an input surface (22) facing the MLA (9) and at least two output surfaces (23,26,33) facing the projection plane (13), the optical expander (17) fanning out and directing the beam path (12) onto the projection plane (13), -Forming an individual projection (14) of the individual image (4) on the projection plane (13) by means of the beam channel (12) directed onto the projection plane (13), and At least partially superimposing the individual projections (14), Wherein the optical expander (17) is arranged such that -The first output surface (23) of the optical expander (17) is provided to direct a first subset (24) of beam channels (12) to a first sub-area (25) of the projection plane (13), and -The second output surface (26) of the optical expander (17) is provided to direct a second subset (27) of beam channels (12) to a second sub-area (28) of the projection plane (13).

Description

Projection with extended illumination area Technical Field The present disclosure relates to optical devices, optical apparatuses, and methods for forming an integral projection. Background Typically, the projection of dynamic images onto a screen is based on a projection device having one imaging optical channel. However, at least when it comes to projection onto inclined or curved surfaces, such devices have several drawbacks, for inclined surfaces, in that a clear image can be achieved by a large range of inclined objects and projection optics. This approach is not suitable for curved projection surfaces. Furthermore, tilting increases the required installation space, which is contrary to the desire for miniaturization. An increased F-number (focal length/aperture size) can solve this problem by increasing the depth of focus, but such an increased F-number is typically accompanied by a lower light intensity. Therefore, for projection on inclined and curved surfaces, it is advantageous to use multichannel optics, such as microlens arrays (MLAs). In this case, a plurality of individual images are projected onto a screen by the MLA and superimposed. The distortion of the overall projection may be compensated for by the fact that the individual images have substantially the same image content, but may be distorted relative to each other and the overall projection. On the one hand, this approach enables a compact design, since the focal length of the microlenses is typically smaller than that of the single-channel optics. On the other hand, multichannel optics exhibit the necessary optical depth of focus anyway to achieve a clear projection on curved or inclined projection surfaces. However, a disadvantage of multi-channel optics is that the illumination area (field of illumination, FOI) is relatively limited. Here and hereinafter, FOI is defined as the width of the cone of light emitted from the optic. The larger the half cone angle of the light cone, the larger the total projection on the screen can be. Thus, to achieve a larger projection, a larger/more MLA is required. However, this in turn results in increased production costs, higher complexity and high alignment effort. It is therefore an object to be achieved to provide an optical device for forming an integral projection which exhibits an increased illumination area. Another object is to provide a method for forming an overall projection with an increased illumination area. This object is achieved by the subject matter of the independent claims. Embodiments and developments of the optical device are defined in the dependent claims. Disclosure of Invention In an embodiment, the optical device comprises an imaging system provided to generate a plurality of images distributed over an imaging plane. The imaging plane is the plane in which the image is generated. The imaging system may be a transmission imaging system. This means that the imaging system can be operated in a transmissive mode. In this case, the imaging system includes, for example, a pattern mask that exhibits a change in transmittance thereof in the lateral direction. The transverse direction extends parallel to the main extension plane of the imaging plane. The pattern mask is arranged in the imaging plane. The pattern mask may be illuminated by a light source, wherein the light source may be comprised in an imaging system. Multiple images are generated in the imaging plane by portions of the light transmitted by the pattern mask. The transmission imaging system will be described in more detail below. The imaging system may also be an emission imaging system. In this case, the imaging system includes, for example, a self-luminous display arranged in an imaging plane. For example, a self-light emitting display is a display including a plurality of Light Emitting Diodes (LEDs). By activating the LED groups, a plurality of images are generated in the imaging plane. Furthermore, the imaging system may also be a reflective imaging system. In this case, the imaging system may comprise a reflective structure arranged in the imaging plane. The reflective structure is illuminated by the light source such that light is reflected by the reflective structure. The portion of the reflected light forms a plurality of images in the imaging plane. The imaging plane extends in the lateral direction. The image may be distributed over the imaging plane in one or more lateral directions. Furthermore, the images may be distributed in a regular or irregular manner over the imaging plane, which means that the distance between adjacent images may be constant or varying. The images or at least a subset of the images may have substantially the same content. They may all represent a version of the overall image. However, the images may also be different from each other. It is possible that the images are distorted relative to each other and to the overall image. The optical device also includes a microlens array (M