Exposure device and method for forming second holographic optical element

Abstract

To record a complicated multiplex wave face type HOE.SOLUTION: In an exposure device 8a including a first holographic optical element 1b, the first holographic optical element has first and second partial regions 10c and 10d. The exposure device includes a first photosensitive substance 70a, and a light unit 100 for creating a first wavelength first light wave 65, a second wavelength first light wave and a second light wave 85. The light unit irradiates the first and second partial regions of the first holographic element with the first light wave. The first photosensitive substance is arranged so that a deflected first partial wave 71a of the first light wave overlaps a deflected second partial wave 71b in a third partial region 90 of the first photosensitive substance. The light unit irradiates the third partial region of the first photosensitive substance with the second light wave so that the second holographic optical element is formed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention particularly relates to an exposure apparatus for manufacturing a second holographic optical element. Further, the present invention relates to a method for manufacturing a second holographic optical element.

Background Art

[0002] Holographic optical elements (HOEs) are known, for example, in applications to head-up displays. In this case, for example, as described in document DE102011075884A1, a hologram may be arranged on the instrument panel of a vehicle in order to deflect light. In this case, for example, a glass body may be used as a support for the hologram.

[0003] Document DE102017218544A1 describes an exposure apparatus for recording a hologram. In this case, the hologram is digitally generated using a spatial light modulator (SLM).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Based on the above, the problem underlying the present invention is to develop an exposure apparatus that enables the recording of complex multi-wavefront HOEs.

Means for Solving the Problems

[0006] To solve this problem, an exposure apparatus for fabricating a second holographic optical element, as described in claim 1, is presented. In addition, a method for fabricating a second holographic element, as described in claim 9, is presented.

[0007] An exposure apparatus configured to fabricate or record a second holographic element primarily includes, firstly, at least a first holographic optical element having at least a first subregion and a second subregion. In this case, the first subregion has at least a first diffraction grating, and the second subregion has at least a second diffraction grating. In this case, the second subregion is positioned differently from the first subregion in particular. In particular, the first and second subregions are positioned adjacent to each other on the first holographic optical element. In this regard, a gap may also be formed between the first and second subregions. Alternatively, the first and second subregions are positioned relative to each other so as to partially overlap in particular. The exposure apparatus further includes a first photosensitive material formed particularly as a first photosensitive film. The first holographic optical element and / or photosensitive material is supported particularly by a support substrate of the exposure apparatus. This support substrate is particularly at least partially transparent glass. In addition, the exposure apparatus includes a light unit for generating a first light wave of at least a first wavelength and for generating a second light wave of at least a first wavelength. The first wavelength light wave is particularly a red light wave. Alternatively, the light unit may be configured to monochromatically generate a first light wave of at least a second wavelength and a second light wave of at least a second wavelength. The second wavelength light wave is particularly a green light wave. Alternatively, the light unit may be configured to polychromatically generate a first light wave of at least a first wavelength and a second wavelength, and a second light wave of at least a first wavelength and a second wavelength. In this case, the first light waves of the first and second wavelengths refer in particular to individual light waves of the first and second wavelengths that overlap with each other, thereby producing wavefronts having different wavelengths. The light unit includes, for example, a first laser generator for generating a red laser wave having a wavelength of λ = 640 nm and a second laser generator for generating a green laser wave having a wavelength of λ = 520 nm. The light unit functions to irradiate at least first and second subregions of a first holographic element with the generated first light wave.In this case, the first photosensitive material is positioned relative to the first holographic optical element such that, in at least a third subregion of the first photosensitive material, the first subwave of the first light wave of the first wavelength deflected by the first diffraction grating and the second subwave of the first light wave of the first wavelength deflected by the second diffraction grating overlap. This situation occurs only when the light unit is configured to simply generate the first light wave of the first wavelength. The first subwave of the first light wave of the first wavelength and the second subwave of the first light wave of the first wavelength are the light waves deflected by the first and second diffraction gratings. That is, the first light wave of the first wavelength is divided into multiple different subwaves by the deflection. As an alternative, the first photosensitive material is positioned relative to the first holographic optical element such that, in at least a third subregion of the first photosensitive material, the first subwave of the first light wave of the second wavelength deflected by the first diffraction grating and the second subwave of the first light wave of the second wavelength deflected by the second diffraction grating overlap. This situation occurs only when the light unit is configured to simply generate the first light wave of the second wavelength. The first subwave of the first light wave of the second wavelength and the second subwave of the first light wave of the second wavelength are the light waves deflected by the first and second diffraction gratings. Furthermore, as an alternative, the first photosensitive material is positioned relative to the first holographic optical element such that, in at least a third subregion of the first photosensitive material, the first subwave of the first light wave of the first and second wavelengths deflected by the first diffraction grating and the second subwave of the first light wave of the first and second wavelengths deflected by the second diffraction grating overlap. This situation occurs when the light unit is configured to generate first light waves of first and second wavelengths. In particular, the first diffraction grating is configured to deflect the first light waves of first wavelength, and the second diffraction grating is configured to intentionally deflect the first light waves of second wavelength.In addition, the light unit is configured to irradiate the photosensitive material with generated second light waves of first and / or second wavelengths such that a second holographic optical element is formed in at least a third subregion of the first photosensitive material by interference between the first and second subwaves of the first light wave and the second light wave. The interference of the first and second subwaves with the second light wave of the same wavelength forms different diffraction gratings in the third subregion. Therefore, it becomes possible to simultaneously form multiple holographic structures in the same subregion of the second holographic optical element, also known as spatial (geometric) multiplexing. Furthermore, if subwaves of different wavelengths interfere with the second light wave having similarly different wavelengths at the same location in the third subregion, so-called spectral multiplexing can also occur. In that case, the diffraction gratings thus formed are effective for various wavelengths / colors. The various holographic structures thus generated can, for example, deflect incoming light in various directions, thereby exhibiting a wide variety of visual functions. Therefore, the fabricated holograms can be used in head-up displays, holographic lenses or holographic filters, and deflectors for lab-on-chip diagnostic imaging.

[0008] Preferably, the first holographic optical element is a transmission hologram. In this regard, the first photosensitive material is positioned relative to the first holographic optical element such that, at least a third portion of the first photosensitive material, particularly on the front surface, a first partial wave of a first light wave of a first wavelength and / or a second wavelength, deflected by a first diffraction grating, overlaps with a second partial wave of a first light wave of a first wavelength and / or a second wavelength, deflected by a second diffraction grating. In this case, the light unit is configured to irradiate the back surface of the photosensitive material with the generated second light wave of a first wavelength and / or a second wavelength, such that, in at least a third portion of the first photosensitive material, the first and second partial waves interfere with the second light wave to form a second holographic optical element. The second holographic element thus generated is appropriately formed as a reflective hologram applicable, for example, to retinal scanning for smart glasses. Geometric multiplexing in a third subregion of a photosensitive material can cause light waves to be deflected in various directions at the same location, thereby enabling the formation of multiple eyeboxes, for example, in smart glasses.

[0009] Preferably, the first holographic optical element further comprises a fourth subregion and a fifth subregion. In this case, the fourth subregion has at least a third diffraction grating, and the fifth subregion has at least a fourth diffraction grating. These subregions are arranged in a rectangular shape. In particular, these subregions are arranged in the first holographic element as a 2x2 array. This provides the advantage of creating two overlapping eye boxes for the smart glasses user, for example, in relation to retinal scanning for smart glasses. Thus, the field of view can be maximized for the smart glasses user.

[0010] Preferably, the holographic gratings of the first and / or second diffraction gratings, particularly the holographic grating planes, are movably arranged. That is, the surface normals of the holographic gratings do not all extend fundamentally parallel to each other, but have position-dependent angles relative to each other, and the holographic gratings are arranged on planes that are fundamentally different from each other, particularly inclined relative to each other, as in the case of concave mirrors or lenses. Preferably, the holographic gratings have diffraction properties that are individually defined, such as in a free-form optical system, rather than diffraction properties that follow a closed mathematical description.

[0011] Preferably, the first holographic optical element has at least a first Vogel and a second Vogel within a first subregion. In this case, the Vogel is a separate, well-defined subhologram digitally recorded on the first holographic optical element using, for example, an SLM. In this case, the first Vogel has at least two, particularly distinct, diffraction gratings. Similarly, the second Vogel has at least two, distinct, diffraction gratings. Thus, one subregion can realize multiple visual functions, thereby potentially expanding, for example, a third overlapping subregion in the formed second holographic element and the overall reachable angular range.

[0012] Preferably, the first holographic element is formed from a second photosensitive material different from the first photosensitive material. Preferably, the first photosensitive material is formed as a photosensitive resin, and the second photosensitive material is formed as a silver halide. Therefore, for example, the first holographic optical element may have a narrow bandwidth, thereby improving the optical quality of the formed second holographic optical element. The transparency of the second holographic optical element can also be improved by the material selection described above. Preferably, the first holographic optical element has a first thickness, particularly a first material thickness, that is different from the second thickness of the second photosensitive material.

[0013] A further subject of the present invention is a method for fabricating a second holographic optical element. In this case, first, at least a first holographic optical element having at least a first subregion and a second subregion is prepared. The first subregion has at least a first diffraction grating, and the second subregion has at least a second diffraction grating. Furthermore, a first photosensitive material, in particular a first photosensitive film, is prepared. In the subsequent step, a first light wave of at least a first wavelength and / or a second wavelength is irradiated onto at least the first and second subregions of the first holographic element. In this case, the first photosensitive material is positioned relative to the first holographic optical element such that, in at least a third subregion of the first photosensitive material, the first subwave of the first light wave of the first wavelength and / or second wavelength, deflected by the first diffraction grating, overlaps with the second subwave of the first light wave of the first wavelength and / or second wavelength, deflected by the second diffraction grating. Furthermore, in particular, simultaneously with the preceding step, a second light wave of at least a first wavelength and / or a second wavelength is irradiated onto the first photosensitive material so that a second holographic optical element is formed in at least a third partial region of the first photosensitive material by interference between the first and second partial waves and the second light wave.

[0014] Preferably, a first partial wave of a first light wave of a first wavelength and / or a second wavelength, deflected by a first diffraction grating, intersects at a first focusing region, particularly a first focal point. This first focusing region, particularly the first focal point, can become the first focal point for the smart glasses user during retinal scanning using the formed second holographic optical element. Preferably, a second partial wave of the first light wave of a first wavelength and / or a second wavelength, deflected by a second diffraction grating, intersects at a second focusing region, particularly a second focal point. This second focusing region, particularly the second focal point, can become the second focal point for the smart glasses user during retinal scanning using the formed second holographic optical element. Preferably, a second light wave of the first wavelength extends toward a third focusing region, particularly the focal point. All focusing regions are located on a common surface, particularly the front or back surface, with respect to the first photosensitive material. When the formed second holographic optical element is illuminated or scanned by a second light wave starting from a third focusing region, a HOE is generated with two side-by-side eye boxes and a focus, suitable for application to smart glasses.

[0015] Preferably, a first light wave of a first wavelength and / or a second wavelength is irradiated onto at least the first and second subregions of the first holographic element such that a third subwave of the first light wave of the first wavelength and / or second wavelength passes through the first diffraction grating without changing its propagation direction, and a fourth subwave of the first light wave of the first wavelength and / or second wavelength passes through the second diffraction grating without changing its propagation direction. In this case, the third and fourth subwaves represent portions of the first light wave that are not intentionally deflected by the diffraction grating. That is, the first light wave of the first and / or second wavelength is divided into a plurality of different subwaves by deflection. Thus, the generation of interfering holograms is prevented or suppressed by the third and / or fourth subwaves that collide with the first photosensitive material and interfere with the second light wave there. Furthermore, in this regard, preferably, the first holographic optical element is configured to be rotated, particularly tilted, with respect to the first photosensitive material so as to increase the angle of incidence of the first light wave. In this case, the angle of incidence is the angle between the first light wave and the surface of the first holographic optical element. By increasing the angle of incidence, and therefore the first light wave being incident relatively horizontally, it is more certain that a portion of the unblinded light wave is irradiated so as to pass through the first photosensitive material.

[0016] Preferably, the first holographic optical element, and more particularly the diffraction grating of the first holographic optical element, is formed digitally. In particular, the first holographic optical element is illuminated using at least one spatial light modulator. Digital holography generally has great advantages in its versatility due to its adaptable recording wavefront using modulation by a spatial light modulator (SLM). This is because various recording conditions can be realized by modulating the recording wavefront. In this case, at least one SLM in at least one optical path may be operated to enable the superposition of multiple phase surfaces. This is equivalent to simultaneously forming multiple apparent light sources, thereby expanding the reachable angular range. Furthermore, simultaneous digital recording of the HOE achieves higher overall efficiency than time-series recording. Moreover, there are fewer interfering factors in the HOE compared to time-series recording. As an alternative, the first holographic optical element, and more particularly the diffraction grating of the first holographic optical element, is formed by at least one other third holographic optical element having at least sixth and seventh subregions. In this case, the sixth and seventh subregions, in particular, are equipped with multiple distinct diffraction gratings, so that the incident light can be deflected in multiple different directions. This multi-step process enables, for example, geometric multiplexing in the first step. Next, this geometric multiplexing is performed for each of the target wavelengths. In the second step, spectral multiplexing is also performed at the target HOE using the auxiliary HOE thus formed. [Brief explanation of the drawing]

[0017] [Figure 1] This is a diagram of the first holographic optical element. [Figure 2] Figure 2a shows a recording of a second embodiment of the first holographic optical element. Figure 2b shows a first embodiment of the exposure apparatus. [Figure 3]FIG. 3a is a diagram showing the recording of a third embodiment of the first holographic optical element. FIG. 3b is a diagram showing a second embodiment of the exposure apparatus. [Figure 4] It is a diagram showing the recording of a fourth embodiment of the first holographic optical element. [Figure 5] It is a diagram showing the recording of a fifth embodiment of the first holographic optical element. [Figure 6a] It is a diagram showing the recording of a sixth embodiment of the first holographic optical element. [Figure 6b] It is a diagram showing a third embodiment of the exposure apparatus. [Figure 7] It is a diagram showing a fourth embodiment of the exposure apparatus. [Figure 8] It is a diagram showing a method of manufacturing a second holographic optical element.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] FIG. 1 schematically shows a side view as a cross-sectional view of a first embodiment of the first holographic optical element 1a. In this case, the first holographic optical element 1a has a first partial region 10a and a second partial region 10b. In this case, the first partial region 10a has a first diffraction grating 20a, and the second partial region 10b has a second diffraction grating 20b. Each partial region 10a, 10b includes a plurality of hologels 30 in this first embodiment of the first holographic optical element 1a. Each hologel 30 also further has at least one diffraction grating. In this case, the diffraction grating is particularly the first and / or second diffraction grating 20a or 20b. In this case, the hologel 30 represents an individual, clearly defined partial hologram digitally recorded on the first holographic optical element 1a, for example, using an SLM.

[0019] The first and / or second diffraction gratings have a holographic grating, particularly formed as a holographic grating plane. These gratings may be arranged movably. That is, the surface normal (not shown here) of the holographic grating has an angle that is particularly position-dependent with respect to each other. In other words, each grating has a different principal plane. The holographic grating may have diffraction characteristics that are not subject to a closed mathematical description but are individually defined, such as those of a free-form optical system, in this regard.

[0020] FIG. 2a schematically shows a side view of the recording of a second embodiment of the first holographic optical element. In this case, a first partial region 10c of the second photosensitive material 7a is simultaneously irradiated by a first light wave 50b of a first wavelength and a fourth light wave 50a of the first wavelength. The first light wave 50b of the first wavelength is irradiated onto the surface of the second photosensitive material 7a in the horizontal direction 40b, and the fourth light wave 50a of the first wavelength is irradiated onto the surface of the second photosensitive material 7a in the inclined direction 40a. In this case, the second photosensitive material 7a is a second photosensitive film supported by a first transparent support substrate (not shown here). Both light waves, 50a and 50b, are irradiated from the front surface of the second photosensitive material 7a onto the first partial region 10c such that the light waves 50a and 50b interfere and a transmissive first diffraction grating is formed in the first partial region 10c. In a subsequent step, a second partial region 10d of the second photosensitive material 7a is simultaneously irradiated by a first light wave 50d of the first wavelength and a fourth light wave 50c of the first wavelength. The first light wave 50d of the first wavelength is irradiated onto the surface of the second photosensitive material 7a in the horizontal direction 40d, and the fourth light wave 50c of the first wavelength is irradiated onto the surface of the second photosensitive material 7a in the inclined direction 40c. Here too, both light waves, 50c and 50d, are irradiated from the front surface of the second photosensitive material 7a onto the second partial region 10d such that the light waves 50c and 50d interfere and a transmissive second diffraction grating is formed in the second partial region 10d.

[0021] In this first embodiment, the formed first holographic optical element further comprises a fourth subregion having a third diffraction grating and a fifth subregion having a fourth diffraction grating, which are located on a shifted plane and are therefore not shown in this figure. The four subregions are spaced apart on the surface of the second photosensitive material 7a in a rectangular shape, particularly as a 2x2 array.

[0022] Figure 2b shows a first embodiment of an exposure apparatus 8a including the first holographic optical element 1b recorded in Figure 2a. The exposure apparatus 8a further includes a first photosensitive material 70a formed here as a first photosensitive film. In this case, the first photosensitive film is supported by a second transparent support substrate (not shown here). The exposure apparatus 8a further includes a light unit 100 for generating a first light wave 65 of at least a first wavelength and a second light wave 85 of the first wavelength. The light unit 100 is configured to irradiate the first light wave 65 onto first and second partial regions 10c, 10d of the first holographic optical element 1b. In this embodiment, the first light wave 65 irradiates the first and second partial regions 10c, 10d in the horizontal direction 60. In this case, the first holographic optical element 1b and the first photosensitive material 70a are arranged basically parallel to each other. The first photosensitive material 70a is positioned relative to the first holographic optical element 1b such that, in a third partial region 90 of the first photosensitive material 70a, the first partial wave 71a of the first light wave 65 of the first wavelength, deflected by the first diffraction grating, and the second partial wave 71b of the first light wave 65 of the first wavelength, deflected by the second diffraction grating, overlap. The light unit 100 is further configured to irradiate the first photosensitive material 70a with a generated second light wave 85 of the first wavelength, such that, in a third partial region 90 of the first photosensitive material 70a, the first and second partial waves 71a and 71b of the first light wave 65 interfere with the second light wave 85 to form a second holographic optical element.

[0023] In this first embodiment of the exposure apparatus 8a, the first photosensitive material 70a is positioned relative to the first holographic optical element 1b such that in a third partial region 90 of the front surface 9a of the first photosensitive material, the first partial wave 71a of the first light wave 65 of the first wavelength, deflected by the first diffraction grating, and the second partial wave 71b of the first light wave 65 of the first wavelength, deflected by the second diffraction grating, overlap. The light unit 100 is also configured to irradiate the back surface 9b of the first photosensitive material 70a with the generated second light wave 85 of the first wavelength, such that in the third partial region 90 of the first photosensitive material 70a, the first and second partial waves 71a, 71b interfere with the second light wave 85 to form a second holographic optical element. In this case, the formed second holographic optical element is formed as a reflective hologram.

[0024] In contrast, in the subregions 95a and 95b adjacent to the third subregion 90, there is no overlap of the subwaves 71a and 71b. In subregion 95a, only subwave 71a interferes with the second light wave 85, and in subregion 95b, only subwave 71b interferes with the second light wave 85.

[0025] In this embodiment, the first holographic optical element 1b is formed from a second photosensitive material 7a that is different from the first photosensitive material 70a. Specifically, the first photosensitive material 70a is formed as a photosensitive resin, and the second photosensitive material 7a is formed as a silver halide.

[0026] Further third and fourth partial waves 75a and 75b, with significantly reduced light intensity, pass through the diffraction gratings of the first and second partial regions 10c and 10d without unintentionally changing their propagation direction. A first light wave 65 of a first wavelength is deflected by a first diffraction grating such that a first partial wave 71a of the first light wave 65 of the first wavelength intersects a first focusing region 88a, particularly at the first focal point. Furthermore, the first light wave 65 of the first wavelength is deflected by a second diffraction grating such that a second partial wave 71b of the first light wave 65 of the first wavelength intersects a second focusing region 88b, particularly at the first focal point. In this embodiment, a second light wave 85 of a first wavelength is irradiated by a light unit 100 onto the surface of the first photosensitive material 70a such that the second light wave 85 extends substantially in a third focusing region 37a, particularly in the direction 80 toward the focal point. The focusing regions 37a, 71a, and 71b are all oriented toward the front surface 9a of the first photosensitive material. When the completed second holographic optical element is placed on one lens of the smart glasses and scanned by retinal scanning starting from the third light-gathering region 37a, two eye boxes with focal points 88a and 88b for the smart glasses user will be created in the first and second sub-regions 10c and 10d. A total of four eye boxes may even be created by arranging them in a 2x2 array.

[0027] Figure 3a shows a schematic side view of a third embodiment of the first holographic optical element. In this case, two subregions 11a and 11b of the second photosensitive material 7b are irradiated with multiple light waves of different wavelengths, unlike in the embodiment of Figure 2a. The first subregion 11a is irradiated with another light wave 51b and another light wave 51a of the first wavelength, while the second subregion is subsequently irradiated with another light wave 51d and another light wave 51c of the second wavelength. The light waves of the first wavelength are particularly red light waves, and the light waves of the second wavelength are particularly blue light waves.

[0028] Figure 3b schematically shows a second embodiment of an exposure apparatus 8b in which the first holographic optical element 1c recorded in Figure 3a is used. Unlike the embodiment in Figure 3a, the first and second partial regions 11a and 11b of the first holographic optical element 1c are simultaneously irradiated horizontally 62 by the light unit 101 with first light waves 68 of a first wavelength and a second wavelength. The first photosensitive material 70b is positioned relative to the first holographic optical element 1c such that, in at least a third partial region 91 of the first photosensitive material 70b, the first partial wave 72a of the first light waves of the first and second wavelengths, deflected by the first diffraction grating, overlaps with the second partial wave 72b of the first light waves of the first and second wavelengths, deflected by the second diffraction grating. The light unit 101 is configured to irradiate the first photosensitive material 70b with the generated second light waves 86 of first and second wavelengths such that a second holographic optical element is formed in a third partial region 91 of the first photosensitive material 70b by interference between the first partial waves 72a and the second partial waves 72b of the first light wave and the second light wave 86. Thus, geometric multiplexing, also known as spectral multiplexing, occurs in the third partial region 91.

[0029] In subregion 96a adjacent to the third subregion 91, the first subwave 72a simply interferes with the second light wave 86. In a further subregion 96b adjacent to the third subregion 91, the second subwave 72a simply interferes with the second light wave 86.

[0030] Further partial waves 56a and 56b, whose light intensity has been greatly reduced, pass through the diffraction gratings of the first and second partial regions 11a and 11b without unintentionally changing their propagation direction. Figure 4 shows a schematic side view of a fourth embodiment of the first holographic optical element. In this case, unlike the previous embodiments, a portion region 12a of the second photosensitive material 7e is irradiated at a first time point by another light wave 52b and another light wave 52a of a first wavelength from directions 42a and 42b, respectively. Thus, a first diffraction grating (not shown) is formed in the first Vogel 31 of the first portion region 12a. At a second time point following the first time point, the first portion region 12a is again irradiated by another light wave 52b and another light wave 52a of a first wavelength from directions 42c and 42d, respectively. Thus, a sixth diffraction grating (not shown) is formed in the second Vogel 32 adjacent to the first Vogel 31 of the first portion region 12a. The different diffraction gratings of the adjacent Vogels 31 and 32 thus formed can broaden the angular range reachable using the completed first holographic optical element.

[0031] Figure 5 schematically illustrates further possibilities for recording with the first holographic optical element. In this case, a first subregion 13a of the second photosensitive material 7c, which is formed as a photosensitive film, is simultaneously irradiated by multiple light waves of a first wavelength. In this case, at a first time point, the first subregion 13a is irradiated by another light wave 53b of a first wavelength from the horizontal direction 43b and another light wave 53a of a first wavelength from the inclined direction 43a. These light waves 53a, 53b interfere with the other light wave 53c of a first wavelength from the horizontal direction 43c on the surface of the second photosensitive material 7c. Thus, multiple different diffraction gratings are simultaneously formed in the first subregion 13a. In particular, this allows individual Vogels to also have multiple different diffraction gratings.

[0032] Furthermore, a second subregion 13b of the second photosensitive material 7c is simultaneously irradiated by multiple light waves of the first wavelength. In this case, at a second time point following the first time point, the second subregion 13b is irradiated by a 16th light wave 53e of the first wavelength from the horizontal direction 43e and another light wave 53d of the first wavelength from the inclined direction 43d. These light waves 53d and 53e interfere with another light wave 53f of the first wavelength from the horizontal direction 43f on the surface of the second photosensitive material 7c.

[0033] Figure 6a schematically shows a cross-sectional view of another embodiment of the formation of the first holographic optical element. In this case, at a first time point, the second photosensitive material 7d is irradiated by another light wave 54c of a first wavelength from a tilt direction 44c, causing interference in the first subregion 14a with another light wave 54a of a first wavelength incident on the surface of the second photosensitive material 7d from the opposing tilt direction 44a. Thus, the first Vogel 33 with the first diffraction grating is formed. At a second time point following the first time point, the first subregion 14a is further irradiated by another light wave 54d of a first wavelength from a tilt direction 44d. In this case, directions 44c and 44d extend parallel to each other. In the first subregion 14a, the other light wave 54d interferes with another light wave 54b of a first wavelength incident on the surface of the second photosensitive material 7d from the opposing tilt direction 54b. Therefore, a second Vogel 34 is formed adjacent to the first Vogel 33, and is equipped with another diffraction grating.

[0034] Figure 6b shows another embodiment of an exposure apparatus 8c in which the first holographic optical element 1f, formed as shown in Figure 6a, is used. In this case, the first partial region 14a and the second partial region 14b of the first holographic optical element 1f are illuminated by a first light wave 66 of a first wavelength from the inclination direction 63. In this case, the direction 63 of the incident first light wave of the first wavelength corresponds to the recording directions 44c and 44d of the first holographic optical element. Thus, the third and fourth partial waves 82a of the first light wave of the first wavelength, passing through the partial regions 14a and 14b without intentionally changing the propagation direction, are radiated to pass through the first photosensitive material 70c, which is positioned parallel to the first holographic optical element 70c. This prevents the formation of an interfering hologram on the first photosensitive material 70c.

[0035] Furthermore, here too, the first photosensitive material 70c is positioned relative to the first holographic optical element 1f such that, in a third partial region 93a of the first photosensitive material 70c, it overlaps with the first partial wave 77a of the first light wave of the first wavelength deflected by the first diffraction grating and the second partial wave 78a of the first light wave of the first wavelength deflected by the second diffraction grating. A light unit (not shown) is configured to irradiate the first photosensitive material 70c with a second light ray 84 of the first wavelength from a tilt direction 83 such that, in a third partial region 93a of the first photosensitive material 70c, the first and second partial waves 77a and 78a of the first light wave interfere with the second light wave 84 to form a second holographic optical element.

[0036] Figure 7 shows a schematic cross-sectional view of a fourth embodiment of the exposure apparatus 8d. In this case, unlike the embodiment in Figure 6b, the first holographic optical element 1f is rotated and particularly tilted relative to the first photosensitive material 70d such that the incident angle 79a of the first light wave 66 of the first wavelength is enlarged compared to Figure 6b. By rotating the first holographic optical element 1f counterclockwise in this manner, the incident angle 79a of the first light wave 66 of the first wavelength, and the reflection angles or incident angles 79b of the first partial wave 77a and the second partial wave 78a can be similarly enlarged. Therefore, the diameter of the incident light wave 66 of the first wavelength is not additionally enlarged or reduced during deflection. Furthermore, aberrations of the first optical element are reduced.

[0037] Figure 8 shows a flowchart illustrating the method for fabricating a second holographic optical element. In this case, at least a first holographic optical element is prepared in step 110. In this case, the first holographic optical element has at least a first subregion and a second subregion. The first subregion has at least a first diffraction grating, and the second subregion has at least a second diffraction grating. The first holographic optical element is formed in particular digitally. For this purpose, at least one spatial light modulator is used to irradiate the first holographic optical element with a second photosensitive material, thereby forming a diffraction grating of the first holographic optical element. As another option, the first holographic optical element is formed by at least one other third holographic optical element having at least sixth and seventh subregions.

[0038] In step 120 following step 110, a photosensitive material, in particular a photosensitive film, is prepared. In step 150 following step 120, a first light wave of at least a first wavelength and / or a second wavelength is irradiated onto at least first and second subregions of the first holographic element using a light unit. In this case, the photosensitive material is positioned relative to the first holographic optical element such that, in at least a third subregion of the first photosensitive material, the first subwave of the first light wave of the first wavelength and / or second wavelength, deflected by the first diffraction grating, overlaps with the second subwave of the first light wave of the first wavelength and / or second wavelength, deflected by the second diffraction grating. In particular, in the subsequent step 160, which is performed simultaneously with step 150, a second light wave of at least a first wavelength and / or a second wavelength is irradiated onto the photosensitive material such that a second holographic optical element is formed in at least a third partial region of the first photosensitive material by interference between the first and second partial waves and the second light wave.

[0039] In an optional step 130 following step 120, a first light wave of the first wavelength and / or second wavelength is irradiated onto the first and second subregions of the first holographic element such that a third subwave of the first light wave of the first wavelength and / or second wavelength passes through the first diffraction grating without changing its propagation direction, and a fourth subwave of the first light wave of the first wavelength and / or second wavelength passes through the second diffraction grating without changing its propagation direction. In a further optional step 140 following step 130, the first holographic optical element is rotated, in particular tilted, relative to the photosensitive material so that the angle of incidence of the first light wave is increased. [Explanation of Symbols]

[0040] 1a, 1b, 1c, 1f First / Second Holographic Optical Elements 8a, 8b, 8c, 8d Exposure equipment 10a, 10c, 11a, 12a, 13a, 14a First subregion 10b, 10d, 11b, 12b, 13b, 14b Second subregion 20a First diffraction grating 20b Second diffraction grating 65, 66 The first light wave of the first wavelength 84, 85 Second light wave of the first wavelength 68 The first light wave of the second wavelength 86. The second light wave of the second wavelength 70a, 70b, 70c, 70d First photosensitive material 71a, 72a, 77a First partial wave 71b, 72b, 78a Second partial wave 90, 91, 93a Third subregion 100, 101 Light Unit

Claims

1. An exposure device (8a, 8b, 8c, 8d) for producing in particular a second holographic optical element (1a, 1b, 1c, 1f), comprising a first holographic optical element (1a, 1b, 1c, 1f) having at least a first partial region (10a, 10c, 11a, 12a, 13a, 14a) and a second partial region (10b, 10d, 11b, 12b, 13b, 14b), the first partial region (10a, 10c, 11a, 12a, 13a, 14a) having at least a first diffraction grating (20a) and the second partial region (10b, 10d, 11b, 12b, 13b, 14b) having at least a second diffraction grating (20b); a first photosensitive material (70a, 70b, 70c, 70d), in particular a first photosensitive film; an exposure device (8a, 8b, 8c, 8d) including a light unit (100, 101) for generating at least a first light wave (65, 66) of a first wavelength and / or a first light wave (68) of a second wavelength, and for generating at least a second light wave (84, 85) of the first wavelength and / or a second light wave (86) of the second wavelength, the light unit (100, 101) is configured to irradiate the generated first light wave (65, 66) onto at least a first partial area (10a, 10c, 11a, 12a, 13a, 14a) and a second partial area (10b, 10d, 11b, 12b, 13b, 14b) of the first holographic element (1a, 1b, 1c, 1f), the first photosensitive material (70a, 70b, 70c, 70d) is arranged with respect to the first holographic optical element (1a, 1b, 1c, 1f) such that in at least a third partial region (90, 91, 93a) of the first photosensitive material (70a, 70b, 70c, 70d), a first partial wave (71a, 72a, 77a) of the first light wave of the first wavelength and / or the second wavelength deflected by the first diffraction grating (20a) overlaps with a second partial wave (71b, 72b, 78a) of the first light wave of the first wavelength and / or the second wavelength deflected by the second diffraction grating (20b), The light unit (100, 101) is configured to irradiate the first photosensitive material (70a, 70b, 70c, 70d) with the generated second light wave (84, 85) of the first wavelength and / or the second light wave (86) of the second wavelength such that a second holographic optical element is formed in at least the third partial region (90, 91, 93a) of the first photosensitive material (70a, 70b, 70c, 70d) by interference of the first partial wave (71a, 72a, 77a) and the second partial wave (71b, 72b, 78a) of the first light wave with the second light wave (85).

2. said first holographic optical element (1a, 1b, 1c, 1f) being a transmission hologram; the first photosensitive material (70a, 70b, 70c, 70d) is arranged with respect to the first holographic optical element (1a, 1b, 1c, 1f) in such a way that at least in the third partial region (90, 91, 93a) of the first photosensitive material (70a, 70b, 70c, 70d), in particular in the front surface (9a), the first partial wave (71, 71b, 77a) of the first light wave of the first wavelength and / or the second wavelength deflected by the first diffraction grating (20a) overlaps with the second partial wave (71b, 72b, 78a) of the first light wave of the first wavelength and / or the second wavelength deflected by the second diffraction grating (20b), 2. The exposure device (8a, 8b, 8c, 8d) according to claim 1, characterized in that the light unit (100, 101) is configured to irradiate a back surface (9b) of the first photosensitive material (70a, 70b, 70c, 70d) with the generated second light wave (84, 95) of the first wavelength and / or the second wavelength such that a second holographic optical element is formed in the at least third partial region (90, 91, 93a) of the first photosensitive material (70a, 70b, 70c, 70d) by interference of the first partial wave (71, 72a, 77a) and the second partial wave (71b, 72b, 78a) with the second light wave (84, 85) of the first wavelength and / or the second wavelength.

3. the first holographic optical element (1a, 1b, 1c, 1f) further comprises a fourth partial region and a fifth partial region, 2. The exposure apparatus (8a, 8b, 8c, 8d) according to claim 1, characterized in that the fourth partial region has at least a third diffraction grating and the fifth partial region has at least a fourth diffraction grating, the partial regions being arranged in a rectangular shape, in particular in a 2x2 array.

4. the first diffraction grating (20a) and / or the second diffraction grating (20b) have a holographic grating, in particular a holographic grating plane, The grating is movably arranged, 2. Exposure apparatus (8a, 8b, 8c, 8d) according to claim 1, characterized in that the surface normals of the holographic gratings have an angle which is particularly position-dependent relative to one another.

5. the first holographic optical element (1a, 1b, 1c, 1f) has at least a first hogel (30, 31, 33) and a second hogel (32, 34) in the first partial region (10a, 10c, 11a, 12a, 13a, 14a), 2. The exposure apparatus (8a, 8b, 8c, 8d) of claim 1, characterized in that the first hogel (30, 31, 33) has at least two, in particular mutually different, diffraction gratings and the second hogel (32, 34) has at least two, in particular mutually different, diffraction gratings.

6. 2. An exposure device (8a, 8b, 8c, 8d) according to claim 1, characterized in that the first holographic element (1a, 1b, 1c, 1f) is formed from a second photosensitive material (7a, 7b, 7c, 7d, 7e) different from the first photosensitive material (70a, 70b, 70c, 70d), in particular a photosensitive resin, in particular a silver halide.

7. 7. The exposure apparatus (8a, 8b, 8c, 8d) according to any one of claims 1 to 6, characterized in that the first holographic optical element (1a, 1b, 1c, 1f) and the first photosensitive material (70a, 70b, 70c, 70d) are arranged essentially parallel to one another.

8. A method of making a second holographic optical element, comprising the steps of: - providing (110) at least a first holographic optical element (1a, 1b, 1c, 1f) having at least a first partial region (10a, 10c, 11a, 12a, 13a, 14a) and a second partial region (10b, 10d, 11b, 12b, 13b, 14b), the first partial region (10a, 10c, 11a, 12a, 13a, 14a) having at least a first diffraction grating (20a) and the second partial region (10b, 10d, 11b, 12b, 13b, 14b) having at least a second diffraction grating (20b); Providing (120) a first photosensitive material (70a, 70b, 70c, 70d), in particular a photosensitive film; A step (150) of irradiating at least a first light wave (65, 66) of a first wavelength and / or a first light wave (68) of a second wavelength onto at least a first partial area (10a, 10c, 11a, 12a, 13a, 14a) and a second partial area (10b, 10d, 11b, 12b, 13b, 14b) of the first holographic element (1a, 1b, 1c, 1f), wherein the first photosensitive material (70a, 70b, 70c, 70d) is at least partially irradiated with a first light wave (65, 66) of a first wavelength and / or a first light wave (68) of a second wavelength. a step (150) in which a first partial wave (71a, 72a, 77a) of the first light wave of the first wavelength and / or the second wavelength deflected by the first diffraction grating (20a) overlaps with a second partial wave (71b, 72b, 78a) of the first light wave of the first wavelength and / or the second wavelength deflected by the second diffraction grating (20b), and a step (160) of irradiating the first photosensitive material (70a, 70b, 70c, 70d) with at least the second light wave (84, 85) and / or the second light wave (86) of the second wavelength such that in at least a third partial region (90, 91, 93a) of the first photosensitive material (70a, 70b, 70c, 70d), a second holographic optical element is formed by interference of the first partial wave (71a, 72a, 77a) and the second partial wave (71b, 72b, 78a) with the second light wave (84, 85) of the first wavelength and / or the second light wave (86) of the second wavelength.

9. the first partial waves (71 a, 72 a, 77 a) of the first light wave of the first wavelength and / or the second wavelength deflected by the first diffraction grating intersect at a first focusing area (88 a), in particular at a first focus, 9. The method according to claim 8, characterized in that the second partial waves (71b, 72b, 78a) of the first light wave of the first wavelength and / or the second wavelength (20b) deflected by the second diffraction grating (20b) intersect at a second focusing region (88b), in particular at a focus.

10. the second light wave (84, 85) of the first wavelength and / or the second light wave (86) of the second wavelength extend in a direction towards a third light collection region (37a), in particular a focal point, 10. The method according to claim 9, characterized in that the light collecting areas (37a, 88a, 88b) are arranged opposite the first photosensitive material (70a, 70b, 70c, 70d) on a common surface, in particular the front surface (9a) or the back surface (9b).

11. A third partial wave (82a) of the first light wave of the first wavelength and / or the second wavelength passes through the first diffraction grating (20a) without changing its propagation direction, a fourth partial wave of the first light wave of the first wavelength and / or the second wavelength passes through the second diffraction grating (20b) without changing its propagation direction, and the third partial wave (82a) and the fourth partial wave pass through the first photosensitive material (70a, 70b, 70c, 70d).

10. The method according to claim 8, further comprising a step (130) of irradiating at least a first partial area (10a, 10c, 11a, 12a, 13a, 14a) and a second partial area (10b, 10d, 11b, 12b, 13b, 14b) of the first holographic element (1a, 1b, 1c, 1f) with the first light wave (65, 66) of the first wavelength and / or the first light wave (68) of the second wavelength such that the first light wave (65, 66) of the first wavelength and / or the second light wave (68) of the second wavelength are emitted in a direction perpendicular to the optical axis.

12. 12. The method according to claim 11, characterized in that the first holographic optical element (1a, 1b, 1c, 1f) is rotated, in particular tilted, with respect to the first photosensitive material (70a, 70b, 70c, 70d) such that an angle of incidence (79a) of the first light wave (65, 66) of the first wavelength and / or the first light wave (68) of the second wavelength is enlarged.

13. 9. The method according to claim 8, characterized in that the first holographic optical element (1a, 1b, 1c, 1f), in particular the diffraction grating of the first holographic optical element (1a, 1b, 1c, 1f), is formed, in particular illuminated, digitally, in particular by means of at least one spatial light modulator.

14. 13. The method according to any one of claims 8 to 12, characterized in that the first holographic optical element (1a, 1b, 1c, 1f), in particular the diffraction grating of the first holographic optical element (1a, 1b, 1c, 1f), is illuminated in particular with at least one further third holographic optical element comprising at least sixth and seventh partial regions.

Images