Arrangement and method for lighting, especially for macro photography, for close-up moving image recordings or for inspections

Abstract

Proposed is an arrangement and method for illumination, particularly for macro photography, with an LED-based light source (1) comprising an LED (1a), a light-collecting optic (4) with a focal length f1, a light-condensing lens (5), and a downstream light-projecting lens (11), both of which are cost-effective interchangeable lenses. The LED (1a) is positioned intrafocally to the light-collecting optic (4) and has an intrafocal focal distance z1 that is greater than or equal to one-tenth and less than or equal to 0.9 times the focal length f1 of the light-collecting optic (4). The LED (1a) thus projects a virtual image B1'v onto the light-collecting optic. The light-condensing lens (6) generates a real image B1'' at close range from the virtual image B1'v. The light-condensing lens (5) is equipped with an iris diaphragm (6) that defines a luminous field LF.The iris diaphragm (6) acts as a field diaphragm for the light-projecting lens (11), which projects the luminous field LF into the object space. The effective flange focal distance a_eff for the light-projecting lens (11) is significantly increased by a predetermined depth offset v compared to its nominal flange focal distance a_np in order to project a light field (14) at close range.

Description

[0001] This article deals with the arrangement and method of lighting, which can be used in particular for macro-photographic purposes, i.e. for macro photography, but also for video recordings and for professional filming in the macro range, i.e. for close-up moving image recordings. The lighting arrangement can be used, for example, for recording or inspecting small objects with dimensions well under 40mm. On the other hand, this lighting arrangement can also be used to illuminate objects at close range during the visual inspection of small details on large objects or for amateur or professional filming in the outdoor field at close range using a video camera, for example when recording small organisms or parts of plants.Furthermore, the lighting arrangement can also be used for inspections in quality control and for inspections in production monitoring as well as at crime scenes for the search for evidence. State of the art

[0002] There are no known prior art illumination arrangements and methods for macrophotography, video and film recordings, or close-up inspections that utilize a current or past commercially available interchangeable camera lens for illumination purposes. These are illumination arrangements and methods that are both compact and comparatively inexpensive, while also enabling the peripheral illumination of a small object or object detail measuring less than 40mm with a very bright light spot or light field. Furthermore, there are no known compact illumination arrangements and methods that can project a light field onto the object at significantly different distances, from 40mm to one meter, from the illumination arrangement, with an illuminance of up to 300.000 lux and with a lateral extension of the light field of, for example, 50 mm.

[0003] The well-known Köhler illumination, sa https: / / www.spektrum.de / lexikon / optik / mikroskopbeleuchtung / 2056 (Accessed 13.10.2023 [1] is designed with a collector, a field diaphragm and a condenser, which is usually either a compact, high-aperture and short-focal-length lens, a two-lens condenser or a multi-lens condenser. Neither a compact, high-aperture and short-focal-length lens, a two-lens condenser nor a multi-lens condenser, which are used in a projector or in a microscope, can produce a fast image of the field diaphragm, for example, at a free distance of up to 500 mm with an image scale of approximately 3:1. Thus, Köhler illumination with a compact, high-aperture and short-focal-length single lens or with a short-focal-length, multi-lens condenser is not suitable for illumination in macro photography at distances of up to one meter.

[0004] Slide projectors have an optical condenser positioned in front of the slide, which in turn is followed by the light-projecting lens. However, a conventional slide projector cannot project a light field at distances of 40 mm to 200 mm from the slide projector, with the lateral extension being variably adjustable. Furthermore, conventional slide projectors use halogen lamps with at least 150 watts, which makes their use for macro photography difficult, if not impossible, due to the air turbulence caused by the ventilation. A slide projector is also so bulky that it can severely restrict access to a small object with a camera.

[0005] Godox offers the Godox S30 LED light, a system with 30 watts of electrical power consumption for advertising photography or video recordings, see https: / / store.godox.eu / de / sonstige-modifikatoren / 5321-godox-sa-p1-projektionsvorsatz-fuer-s30-6952344218082.html

[0006] (Accessed October 13, 2023) [2]. The diameter of the projected light field in the Godox SA-P1 projection attachment is around 45mm. This allows a variety of patterns to be projected using different shading apertures of this size in order to fully illuminate object details in a field of, for example, one square meter. However, even for the Godox SA-03 150mm telephoto lens with a 150mm focal length, the full projected light field is always well above 45mm in diameter. By using a small aperture, a light field in the form of a light spot with, for example, a diameter of only 4mm can be projected, but this is then not very bright. However, these small projected light fields are comparatively weak for use in macro photography.A system based on the Godox S30 LED light is therefore not a suitable and cost-effective system for macro photography or for amateur or professional filming in the outdoor field with light fields significantly less than 40 millimeters in lateral dimension and a very high illuminance in the light field.

[0007] Patent DE 10 2022 001 895 B3 describes an arrangement for generating a spaced, adjustable light field for macrophotography, in particular for object-adapted illumination with a sharp light field edge. The use of a flexible fluid light guide described therein does not allow for the production of a comparatively cost-effective, compact light source assembly for a lighting arrangement, especially for macrophotography. This is because the distance between the continuous light source with a high-performance single-cell LED and the light field is at least 1.2 meters, which does not constitute a compact arrangement.

[0008] Patent DE 10 2022 112 151 B3 describes an imaging visualization system, which is designed in particular as an exoscope, microscope, macroscope, or endoscope and / or configured for stereoscopic imaging of objects. It comprises imaging optics with a variable focal length and illumination optics for illuminating an illumination field. The visualization system comprises an external light source that supplies the illumination optics with illumination light. The light source has an adjustment means for adapting an angular spectrum of the illumination light emanating from the illumination optics, and the illumination light is coupled into a light guide that transports the illumination light from the external light source to the illumination optics. However, a light guide is not intended to be used in the present document. Aim of the invention

[0009] The aim is to teach how a comparatively cost-effective arrangement and method for lighting can be put to economic use, particularly for macro photography, for close-up motion picture recordings or for close-up inspections. Object of the invention

[0010] By means of an illumination arrangement and method, it should be possible to achieve a very high intensity of the light in a projected light field for object illumination for macro-photography purposes, for filming in the macro range, i.e. for close-up moving image recordings, or for illuminating objects at close range - including for crime scene inspection. This includes not only visual inspection but also automatically performed inspection. The lateral extent of the light field projected onto the object should be adjustable within wide limits, but should generally be well below 100 mm. The light field should also be able to be focused at different depths at close range above 40 millimeters and below one meter at a distance from the illumination arrangement. The achievable illuminance in the projected light field on the object should be at least 10 thanks to the compact illumination arrangement.000 lux and up to 300,000 lux or even more if a small light field is projected. In extreme cases, it should also be possible to achieve 500,000 lux in the projected light field, for example, which requires eye safety measures. There should be no ground glass in the optical beam path of the illumination arrangement so as not to attenuate the light. The aim should be to achieve either a high level of uniformity in the illuminance in the light field or a predetermined decrease in illuminance towards the edge of the light field. Furthermore, it should be possible to continuously focus the light field over at least a partial area in depth or to gradually adjust the focus position in depth.Above all, the lighting arrangement should allow flexible adaptation to very different lighting situations with regard to the free working distance from the lighting arrangement to the object to be recorded as well as with regard to light field size and illuminance.

[0011] Furthermore, the intensity of the light in object lighting, i.e. the illuminance, should be adjustable within wide limits - at least by electrical means - and adapted to the respective lighting task. Description of the invention

[0012] The arrangement for lighting, especially for macro photography, for close-up motion picture recordings or for inspections is with an LED-based light source, with a light-collecting optic, with a light-condensing lens and with a light-projecting lens trained.

[0013] The LED-based light source either by means of an LED or as a group of LEDs or as an LED unit or as an LED array or as a battery-operated light cube of the Lume Cube type from the US company Lume Cube, Inc.

[0014] The LED has an emitting surface with the point PL on the optical axis OA, and the light-collecting optics are arranged downstream of the emitting surface. Furthermore, the light-collecting optics are designed either with a single converging lens or as a light-collecting multiple lens system. The light-collecting optics have a focal length f1 and a focal point F1. The LED is arranged with its emitting surface intrafocally to the light-collecting optics. The emitting surface of the LED with the point PL has an intrafocal focal point distance z1 from the focal point F1 that is greater than or equal to one tenth and less than or equal to 0.9 times the focal length f1 of the light-collecting optics. Thus, the LED is virtually imaged at finite distance by the light-collecting optics with the virtual image B1'v. The light-condensing lens is arranged downstream of the light-collecting optics, and the light-condensing lens is designed with an iris diaphragm.Thus, a luminous field LF is defined by the iris diaphragm in the light-condensing lens, and at least one light-gathering lens is arranged downstream of the iris diaphragm in the light-condensing lens, and a virtual image LF'v is formed in front of the iris diaphragm by the at least one light-gathering lens in the light-condensing lens. However, the iris diaphragm in the light-condensing lens also acts as an opening diaphragm for the light emanating from the virtual image B1'v. This iris diaphragm in the light-condensing lens thus has a dual optical function, acting both as an opening diaphragm, also known as an aperture diaphragm, and as a field diaphragm. Since it limits the luminous field, this field diaphragm is therefore a luminous field diaphragm for the light-projecting lens, which is arranged downstream of the light-condensing lens.A light-projecting lens with a focal length f2 is arranged downstream of the light-condensing lens, and the light-projecting lens is used to project the virtual image LF'v of the luminous field LF into the object space. For good light-optical efficiency, the focal length f2 is preferably greater than or equal to the focal length f1. In the object space, a real image LF" of the virtual image LF'v of the luminous field LF exists as a projected light field. The distance of the light-projecting lens from the virtual image LF'v for this light-projecting lens creates an effective flange focal distance a_eff, which is significantly increased by a predetermined depth offset v compared to its nominal flange focal distance a_np according to the manufacturer's specifications.The effective flange focal distance a_eff for the light-projecting lens represents the distance of the virtual image LF'v in the light-condensing lens from the mounting surface A12 of the light-projecting lens, as seen from the light-projecting lens. This effective flange focal distance a_eff results from the addition of the nominal flange focal distance a_np and a predetermined depth offset v, which is determined from the focal point F3 to the virtual image LF'v. The predetermined depth offset v is greater than or equal to 0.1 times the focal length f3 and less than or equal to the focal length f3 of the light-projecting lens according to the lens manufacturer's specifications. With a depth offset v of 0.1 times the focal length f3 of the light-projecting lens, the projected light field is created in the object space at a distance 10 times from the rear focal point F3' of the light-projecting lens, thus already at a quite large distance from the light-projecting lens.In contrast, with a depth offset v equal to the focal length f3 of the light-projecting lens, the projected light field in the object space is created at close range at a distance from the rear focal point F3' of the light-projecting lens. However, for the lighting efficiency of generating a projected light field in the object space, a depth offset v of one-quarter to one-half of the focal length f3 of the light-projecting lens is advantageous. In this case, a commercially available photo or video lens, if it is a standard lens or telephoto lens and not a macro lens, is being used outside its specifications, since the nominal close-up range specified by the manufacturer for these lenses is usually more than five to ten times the focal length.Using the LED for imaging at close ranges below the nominally specified minimum focal length by the manufacturer generally compromises image quality – in this case, the image quality of the projected light field in object space. However, this is generally acceptable for illumination purposes. For very high image quality requirements, a macro lens must be used, which generally results in considerable additional costs compared to a standard lens. The maximum lateral dimension of the LED's emitting surface is less than or equal to the diameter d3 of the lens mount in the light-projecting lens through which the light enters the light-projecting lens. This lens is the rear lens of the lens in the manufacturer's intended use, but here it is the entrance lens for the light into the light-projecting lens.This adaptation of the lateral dimension of the emitting surface to the diameter d3 of the lens mount reduces light losses, as otherwise the incoming light would far outshine the lens in diameter. In many cases, it can be advantageous if the lateral dimension of the LED's emitting surface is preferably only approximately half the diameter d3 of the lens mount. The distance of the light field from the light-projecting lens is greater than or equal to 1.5 times the focal length f3 of the light-projecting lens.

[0015] For a macro lens, such as the 7Artisans macro lens with a 60mm focal length, a maximum aperture of f / 2.8, and a Fujifilm X-mount, the depth of field (v) can be zero. Thus, the distance of the virtual image LF'v of the light field LF is equal to the nominal flange focal distance a_n of a macro lens. For the example of the 7Artisans macro lens with a 60mm focal length and a Fujifilm X-mount, the flange focal distance is 17.7mm. This allows a sharp focus of the light field from 90mm from the lens mount to infinity, giving the user the greatest possible flexibility in the lighting setup. However, macro lenses are more expensive than standard lenses, especially small video lenses with a C-mount connection, and this flexibility is not necessary for every application.However, a macro lens from the photography range with a focal length of 50mm to 105mm can also be used very effectively if the depth of field v is one-tenth of its focal length. Then, with the focus set to infinity, the projected light field is approximately ten times its focal length. The resulting focus range is then very well suited for macro photography and for close-up photography and inspections.

[0016] In the illumination arrangement, the light-gathering optics can preferably be designed as a converging lens with a focal length f1 between 5 mm and 100 mm. This can be a highly asymmetrical converging lens, in particular a plano-convex lens. The larger lens belly of the converging lens faces the light-condensing objective and the less curved lens surface faces the LED. It is preferably also possible to use an LED-based light source without downstream light-gathering optics. However, the illuminance in the projected light field is then significantly lower compared to an arrangement with light-gathering optics, which can be designed as a matched, asymmetrical converging lens. For example, the illuminance is considerably lower if an LED-based light source is used without light-gathering optics compared to an arrangement with a matched converging lens.It is also possible to position an LED directly in front of the light-condensing lens, although this would at least halve the achievable illuminance in the projected light field in the object space. If an LED has a directly attached, short-focal-length converging lens, this attached converging lens corresponds to the downstream light-collecting optics. This is the case with the Lume Cube 2.0 light cube from the US company Lume Cube Inc. However, in some cases it may be useful to follow this LED with the directly attached converging lens with another converging lens in order to create the virtual image of the emitting surface at an optimal distance from the light-condensing lens. In this case, the light-collecting optics represents a two-lens system.If an LED has a large number of attached microlenses, it is generally advantageous to follow the attached microlenses with another converging lens to create the virtual image of the emitting surface at an optimal distance from the light-condensing lens. In this case, the light-collecting optics represent a multi-lens or multi-lens array.

[0017] Furthermore, in the illumination arrangement, the light-condensing lens can preferably be designed as a commercially available, interchangeable video, film, or photo lens, either currently or in the past. This includes standard and low-telephoto lenses as well as a macro lens. Wide-angle lenses are generally less suitable here, as they result in light fields with a particularly short free working distance, although this can sometimes be useful in special applications.

[0018] Preferably, in the arrangement for illumination, the light-condensing lens can preferably be designed with a focal length f2 between 5mm and 85mm.

[0019] Furthermore, in the arrangement for illumination, the light-projecting lens may preferably be designed as a commercially available and interchangeable video, film or photo lens.

[0020] Preferably, in the arrangement for illumination, the light-projecting lens can be designed with a lens mount common in the photo, film or video world.

[0021] In addition, in the illumination arrangement, the light-projecting lens can preferably be designed with a focal length f3 between 10mm and 200mm.

[0022] Furthermore, in the illumination arrangement, the predetermined depth offset v can preferably be greater than or equal to 0.3 times the focal length f3 and less than or equal to the focal length f3 of the light-projecting lens according to the lens manufacturer's specifications. This allows for a short free working distance to the object, which is not significantly greater than three times the focal length of the light-projecting lens, as well as a very bright light field.

[0023] Furthermore, in the illumination arrangement, the predetermined depth offset v can preferably be greater than or equal to 0.5 times the focal length f3 and less than or equal to the focal length f3 of the light-projecting lens according to the lens manufacturer's specifications. This enables a particularly short free working distance to the object, which is not significantly greater than twice the focal length of the light-projecting lens, as well as a particularly bright light field.

[0024] Furthermore, in the illumination arrangement, the light-condensing lens and the light-projecting lens can preferably be connected to one another by an intermediate piece in order to achieve a mechanically stable arrangement.

[0025] Furthermore, in the arrangement for illumination, the intermediate piece can preferably be arranged with its lens connection on the lens connection of the light-condensing lens.

[0026] Furthermore, in the arrangement for illumination, the intermediate piece can preferably be designed on both sides with a lens connection generally known in the photo, film or video world. This can be one of the following lens mounts: Alpa, Altix V, Altix n / nb, Canon FD, Canon FL, Canon EF, Canon EF-S, Canon RF, Contarex, Contax G, Contax 645, Contax N, Contax RF, Contax S / Pentacon, Contax / Yashica, Exakta, Kiev 60, Fujica-X, Fujifilm X, Konica AR, Konica F, Leica (M39 LTM), Leica M, Leica R, Minolta A (AF), Minolta MD, Minolta SR, Minolta V, Miranda, Nikon 1, Nikon CX, Nikon S, Nikon Z, Nikon F, Olympus E, Olympus Four Thirds, Olympus OM, Olympus Pen F, Pentaflex 8, Pentax (M42x1), Pentina, Praktica B, Praktica (M42x1), Praktiflex (M40x1), Praktina, Rollei 35mm QBM bayonet, Samsung NX, T2 (M42x0.75), Topcon RE, Yashica MA, Voigtländer QBM, Zenit, sa https: / / de.wikipedia.org / wiki / Auflagemaß.

[0027] Furthermore, in the illumination arrangement, the light-condensing lens can preferably be designed with a C-mount lens connection. However, it is also possible for the light-condensing lens to be designed with a CS-mount lens connection.

[0028] Furthermore, in the illumination arrangement, the light-projecting lens can preferably be designed with a C-mount lens connection. However, it is also possible for the light-projecting lens to be designed with a CS-mount lens connection.

[0029] Furthermore, in the arrangement for illuminating the LED, an accumulator with a current controller is preferably assigned for operation.

[0030] The lighting process, especially for macro photography, for close-up motion picture recordings or for inspections, is with an LED, with a light-collecting lens, with a light-condensing lens and carried out with a light-projecting lens.

[0031] The LED, arranged intrafocally to the light-collecting optics, with its emitting surface is imaged by the downstream light-collecting optics. The emitting surface, at point PL, has an intrafocal focal distance z1 to the focal point F1 that is greater than or equal to one tenth and less than or equal to 0.9 times the focal length f1 of the light-collecting optics. Thus, a virtual image B1'v of the LED's emitting surface is formed by the light-collecting optics. The virtual image B1'v is imaged by the light-condensing lens, creating a real image B1'' downstream of the light-condensing lens with the image positioned in the extrafocal near field of the light-condensing lens. Preferably, the extrafocal focal distance z2' from the focal point F2' to the real image B1'' of the LED with its emitting surface can have at least the value of the intrafocal focal distance z1.An iris diaphragm in the light-condensing lens limits both the opening of the light-condensing lens for the light beam from the virtual image B1'v of the LED 1a as an aperture diaphragm, and the iris diaphragm, as a field diaphragm, limits a light field LF in the light-condensing lens for a light-projecting lens that is arranged downstream of this light-condensing lens. A light-gathering lens, which is arranged downstream of the iris diaphragm in the light-condensing lens, images the light field LF and its edge into a virtual light field LF'v. The virtual light field LF'v is the exit pupil of the light-condensing lens. Depending on the requirements when photographing an object or during visual or automatic inspection, the virtual light field LF'v can be imaged sharply or less sharply.The virtual luminous field LF'v as a light object is placed in front of the light-projecting lens and this virtual luminous field LF'v from the light-projecting lens is projected at a significant distance into the object space as a real image LF'', which represents a light field for illuminating an object.

[0032] Furthermore, the light-condensing lens and the light-projecting lens are preferably splash-proof. Character description

[0033] The invention is described by means of the figure and the detail in the figure, as well as 12 further exemplary embodiments without figures, whereby the figure drawing is not drawn to scale. The figure illustrates the principle of a compact lighting arrangement. The white LED 1a in the LED-based light source 1 with the radiation surface 1b and an edge length of the square radiation surface 1b of approximately 6 mm as well as a point PL on the optical axis OA and a heat sink (not shown here) emits white light. This LED 1a is sensitively adjustable in depth and is supplied with electrical energy via a current controller 2 from a powerful accumulator 3. The LED 1a is operated with a voltage of approximately 12 volts. The operating current for the LED 1a can be adjusted within wide limits via the current controller 2, here up to 2 amperes at a voltage of approximately 11.6 volts.This current controller 2 is connected to a battery 3 and thus regulates the luminous flux emitted by the LED 1a as required when illuminating an object. The maximum possible current is up to 4 amperes at a maximum voltage of 12.5 volts. The light from the LED 1a strikes a converging lens 4a in the light-collecting optics 4. This is designed as a short-focal-length plano-convex lens, the flat surface of which faces the LED 1a and which has the vertex S1 on the rear side. The focal length f1 of the converging lens 4a is 26 mm and is calculated from the principal point H1 to the focal point F1, and the average focal length fS1 is 18 mm. This converging lens 4a concentrates the light from the LED 1a downwards. The LED 1a is intrafocally positioned here. The focal distance z1 from the focal point F1 is 6.5 mm. This creates a virtual image B1'v of the emitting surface 1b of the LED 1a with the point PL'v on the optical axis OA.A light-condensing lens 5 is arranged downstream of the converging lens 4a. This lens is not specifically designed as a condenser lens. Rather, it is a commercially available, inexpensive video lens, either present or past, with an iris diaphragm 6 with twelve diaphragm blades 6a and a lens mount 7, which condenses the light. This light-condensing lens 5 has at least two lenses. However, only the front lens 5a and the rear lens 5b are shown here. The lens mount 7 of the light-condensing lens 5 is a standardized C-mount lens mount at the downstream end. This light-condensing lens 5 has a focal length of 35mm and a maximum aperture of 1:1.6. There is a mechanical connection between the light-collecting optics 4 and this light-condensing lens 5 at its front end.This connection is not shown here, as connecting optical components is familiar to a technically trained expert. The distance d1 of the converging lens 4a from the front lens 5a of the light-condensing lens 5 is d1=7mm, but this can only be approximately maintained, i.e., within a tolerance range of plus or minus 2 millimeters. For the light-condensing lens 5, the virtual image B1'v of the emitting surface 1b of the LED 1a is the light object to be imaged, which is located at a distance of approximately 80mm upstream from the lens vertex S2 of the front lens 5a and has an edge length of approximately 24mm.

[0034] The light entering through the front lens 5a reaches the iris diaphragm 6 within the light-condensing lens 5. The iris diaphragm 6 is integrated into the light-condensing lens 5 and is formed with 12 diaphragm blades 6a that span a plane E. The iris diaphragm 6 defines a light field LF as a light object in the plane E. For the imaging of the virtual image B1'v of the LED 1a, the iris diaphragm 6 acts as an opening diaphragm, also known as an aperture diaphragm, according to the manufacturer's optical design in the application intended by the manufacturer. The transmission range of the iris diaphragm 6 represents a light field LF with the point P on the optical axis OA. The iris diaphragm 6 simultaneously serves as both an aperture diaphragm for the light beam emanating from the LED 1a and a field diaphragm from the perspective of the light-projecting lens 11.

[0035] The light transmitted through the iris diaphragm 6 strikes the downstream light-gathering lens 5b in the light-condensing lens 5, which here is the rear lens of the light-condensing lens 5. This light-gathering lens 5b slightly focuses the transmitted light and also forms a virtual image LF' of this light with the virtual point P' of the light field LF in the diaphragm plane E. This virtual image LF' is located close to the light-gathering lens 5b, but according to the laws of geometric optics, upstream of it. The light-condensing lens 5 has a lens mount 7 with a support surface A7 at its rear end. This lens mount 7 is designed here as a C-mount lens mount, which is mechanically connected to the downstream intermediate piece 8 via the C-mount mount, since the intermediate piece 8 also has a front lens mount 9 with a support surface A9.This lens mount 9 fits the C-mount lens mount of the light-condensing lens 5, as both are C-mount. The intermediate piece 8 is adjustable in length and is set here to the distance d2 between the support surfaces A9 and A10, with the support surface A10 located on the rear lens mount 10. The intermediate piece 8 consists of two threaded pieces (not shown here) that are screwed together to allow its distance d2 to be varied over a fairly wide range. Thus, the intermediate piece 8 is adjustable in length within a range of 27 mm to 42 mm.

[0036] In the figure, the intermediate piece 8 is set to a distance d2 of 37 mm between the support surface A9 and the support surface A10. The lens mount 10 of the intermediate piece 8 is used to accommodate a light-projecting lens 11 with a lens mount 12 and an iris diaphragm 13. The lens mount 10 is of the C-mount type in this case, allowing the attachment of a cost-effective video lens with a C-mount lens mount, widely produced in the present or past, as the light-projecting lens 11. This light-projecting lens 11 attached to the lens mount 10 is a video lens with a lens mount 12, which is designed here as a C-mount lens mount. The light-projecting lens 11 has a focal length of 50mm and a maximum aperture of 1:1.4, i.e. aperture 1.4, and a minimum aperture of 1:16, i.e. aperture 16, and is declared as a CCTV lens.This light-projecting lens 11 has a lens 11a, which, in the use intended by the manufacturer, represents a rear lens. However, in the arrangement shown in the figure, this lens 11a represents an entrance lens in optical use. Furthermore, this light-projecting lens 11 has an iris diaphragm 13, which represents an aperture stop formed with diaphragm blades 13a. For this light-projecting lens 11, the virtual image LF' with the virtual point P' in the light-condensing lens 5 now represents the light object being imaged by it. The light-projecting lens 11 thus serves to project the virtual image LF'.Thus, the virtual image LF' of the luminous field LF defined by the iris diaphragm 6 now represents the field to be imaged for the downstream light-projecting lens 11, and the iris diaphragm 6 acts as a field diaphragm that limits a luminous field, even though the manufacturer intended this iris diaphragm 6 to be an aperture diaphragm. However, the effect of an aperture ultimately depends on its position and configuration within an optical arrangement and not always on the manufacturer's optical design, and especially on the position of the object. This iris diaphragm 6 therefore represents an aperture diaphragm for the virtual image B1'v of the emitting surface 1b of the LED 1a, since it is located at a sufficiently large distance from the front lens 5a.

[0037] The iris diaphragm 6 is thus, from the perspective of the light-projecting lens 11, a field diaphragm. The edge of the virtual image LF' is sharply imaged. Thus, in the space downstream of the light-projecting lens 11, referred to here as the object space, the real image LF" of the illuminated field LF, which here represents the light field 14, is created. The object to be illuminated, which is not shown here, is located in the object space. The light field 14 thus generated, with its sharply imaged edge, can thus be used to illuminate the object or an object detail, which can be an object for macro photography, for motion picture recordings, an object at a crime scene, or even an object in a manufacturing or repair process. By defocusing using the light-projecting lens 11, a blurred edge of the light field 14 can also be created if necessary.

[0038] The light-projecting lens 11, in the form of a cost-effective C-mount lens, has a nominal flange focal distance of 17.526 mm. However, the intermediate piece 8, which is set here to a distance d2 of 37 mm between the support surface A9 and the support surface A10, causes a depth offset v of approximately 25 mm. This results in an effective flange focal distance a_eff for the imaging of the virtual image LF' by the light-projecting lens 11 of approximately 42.5 mm. This results in an imaging scale betaP_strich of approximately 2:1 for the imaging of the virtual image LF'. The diameter of the virtual image LF', which is determined by the setting of the iris diaphragm 6, is approximately 13 mm here when the iris diaphragm 6 is fully open.The diameter of the virtual image LF' and the diameter of the iris diaphragm 6 differ only slightly here, since the iris diaphragm 6 is arranged quite close to the lens 11a, and thus the virtual image LF' of the light field LF, with its extent, also roughly corresponds to the opening of the iris diaphragm 6 with the diaphragm plane E. Thus, a light field 14 is created by the light-projecting lens 11, which here has a diameter of approximately 26 mm. By adjusting the iris diaphragm 6 on the light-condensing lens 5, the extent of the light field 14 can be adjusted within wide limits—depending on the diaphragm position between diaphragm 1.4 and diaphragm 16. If the LED 1a is operated with 23 W of electrical energy, an illuminance of approximately 200 results.000 lux in the center of the light field 14 with a drop in illuminance towards the sharp edge of the light field 14 of a few percent, which should generally meet the requirements when photographing an object or during visual inspection.

[0039] The mount 11b of the lens 11a, with the diameter d3 of the mount and thus an effective diameter of the lens 11a of approximately d3=14mm, represents the effective aperture when the aperture 1.4 is set on the light-projecting lens 11—in the described embodiment, a cost-effective video lens with the maximum aperture 1.4. Only when an aperture with an f-number of 2 or an even smaller aperture is set does the iris diaphragm of the interchangeable lens 11 become optically effective, and in any case, this only acts as an aperture. The effective diameter d3 of the mount 11b of the lens 11a is therefore crucial here, and not just the light intensity of the light-projecting lens 11, in order to achieve a high illuminance in the projected light field 14, although a high light intensity of the light-projecting lens 11 always requires a large effective diameter of the lens 11a.

[0040] The detail in the figure represents the real and approximately square image B1'' of the square radiation surface 1b of the LED 1a. The real and approximately square image B1'' has an edge length of approximately 12 mm. This image B1'' is created between the two lens mounts 10 and 12 with the support surfaces A10 and A12 using the three light beam bundles LSB, which are only examples here. Shown are the real image points P1'' and PL1'', which are imaged by the radiation surface 1b of the LED 1a. With the edge length of the image B1'' of approximately 12 mm, this results in a very good photometric adaptation to the lens 11a, which is arranged a short distance downstream of the real image B1'' and has a usable diameter of approximately 14 mm.

[0041] In a first embodiment according to the figure, but without a separate figure, instead of the converging lens 4a with the focal length f1 of 26 mm and a diameter of 30 mm, a light-collecting plano-convex lens with the focal length f1 of 25 mm and a diameter of 25 mm is arranged, which can be advantageous for the structural design due to the smaller diameter and also for cost reasons, without the illuminance in the projected light field 14 being significantly reduced.

[0042] In a second embodiment according to the figure, but without a separate figure, a rigid intermediate piece 8 is arranged. The distance d2 here is 37 mm. A rigid intermediate piece is advantageous for cost reasons when high flexibility in the application of the lighting arrangement is not required, for example, in a fixed installation during inspection in production.

[0043] In a third embodiment according to the figure, but without a separate figure, the lens connection 10 of the intermediate piece 8 is designed as in a 35mm SLR camera in order to be able to accommodate an interchangeable lens for a 35mm SLR camera for the 35mm or APS-C format as a light-projecting lens 11.

[0044] In a fourth embodiment according to the figure, but without a separate figure, the lens mount 10 of the intermediate piece 8 is a Canon EF lens mount, in order to accommodate an interchangeable lens with a Canon EF lens mount as the light-projecting lens 11.

[0045] In a fifth embodiment according to the figure, but without a separate figure, the lens connection 10 of the intermediate piece 8 is a Nikon F lens connection in order to be able to accommodate an interchangeable lens with a Nikon F lens connection as the light-projecting lens 11.

[0046] In a fifth embodiment according to the figure, but without a separate figure, the lens connection 10 of the intermediate piece 8 is an M42 lens connection in order to be able to accommodate an older interchangeable lens with an M42 lens connection as a light-projecting lens 11.

[0047] In a sixth embodiment according to the figure, but without a separate figure, the lens connection 10 of the intermediate piece 8 is a Fujifilm X-bayonet lens connection in order to be able to accommodate an APS-C interchangeable lens with a Fujifilm X-bayonet lens connection as the light-projecting lens 11.

[0048] In a seventh embodiment according to the figure, but without a separate figure, the LED 1a is arranged in a commercially available flashlight.

[0049] In an eighth embodiment according to the figure, but without a separate figure, the LED 1a is arranged next to other LEDs in a commercially available flashlight.

[0050] In a ninth embodiment according to the figure, but without a separate figure, several additional LEDs with different light spectra are arranged next to LED 1a, forming a group of LEDs. This allows a high value for the color rendering index to be achieved.

[0051] In a tenth embodiment, but without a separate figure, a Lume Cube 2.0 light cube from the US company Lume Cube Inc. is used as the LED-based light source 1. The light-gathering optics 4 are designed here in the Lume Cube 2.0 as an integrated short-focal-length lens 4a and are arranged directly downstream of the radiating surface 1b, so that the existing intrafocal focal distance z1 from below already approaches 0.9 times the focal length of the integrated lens 4a. The light-condensing lens 5 has a focal length of 35 mm and a light intensity of 1:1.6. With this Lume Cube 2.0, an illuminance of approximately 20,000 lux can be achieved in the light field 14 at a magnification of 2:1 at full electrical power, which is often sufficient in the amateur sector when working even without a tripod.

[0052] In an eleventh embodiment, but without a separate figure, a Lume Cube 2.0 light cube from the US company Lume Cube Inc. is used as the LED-based light source 1. This Lume Cube 2.0 with the integrated lens is externally followed by a non-anti-reflective biconvex converging lens 4a with a focal length f1 of 42 mm. The light-collecting optics 4 here therefore consists of the lens integrated into the Lume Cube 2.0 and the externally arranged converging lens 4a and thus represents a two-lens system. The downstream converging lens 4a follows the Lume Cube 2.0 at a short distance, and thus the intrafocal focal distance z1 is only 22 mm. The light-condensing lens 5 has a focal length of 35 mm and a light intensity of 1:1.6.The light-projecting lens used—in contrast to the arrangement in the figure—is a 7 Artisans lens with a focal length of 55mm and a maximum aperture of f / 1.4, coupled with a Fujifilm X-mount with a flange focal distance of 17.7mm and infinity focus. The distance d2 between the two mounting surfaces A7 and A12 is 43mm. The diameter d3 of mount 11b of lens 11a, which is the rear lens of this lens and serves as the entrance lens here, is approximately 21mm. With this 7 Artisans lens, an illuminance of approximately 46,000 lux can be achieved in the light field 14 at full power of the Lume Cube 2.0 from the US company Lume Cube Inc., estimated at approximately 5W. The free working distance is approximately 115mm and the magnification is approximately 2:1. The diameter of the light field here is approximately 26mm, resulting in an illuminance of approximately 46.000 lux in the light field 14 represents a fairly comfortable working environment – ​​even without a tripod. The advantage of this light-projecting lens 11 of the 7Artisans type is that, thanks to the comparatively large diameter d3 of the mount 11b of its lens 11a, the light of the entire real image B1'' of the Lume Cube 2.0's radiating surface enters the lens without lateral limitation. This creates a white light field 14 with the color temperature of 5600 K and the Color Rendering Index (CRI) of 95 specified by the manufacturer Lume Inc.

[0053] In a twelfth embodiment, but without a separate figure, a Lume Cube 2.0 light cube from the US company Lume Cube Inc. is used as the LED-based light source 1. The light-gathering optics 4 are designed as an integrated lens 4a in the Lume Cube 2.0 and are arranged directly downstream of the radiating surface 1b, so that the existing intrafocal focal distance z1 from below already approaches 0.9 times the focal length of the integrated lens 4a. No further individual lens follows. The light-condensing lens 5, which is a cost-effective video lens and is arranged directly downstream of the Lume Cube 2.0 light cube without a distance, has a focal length of 35 mm and a speed of 1:1.6.In contrast to the arrangement in the figure, the light-projecting lens used here is an older Revuenon lens with a focal length of 55mm and a maximum aperture of 1:1.4, as well as an M42 screw mount, which can be used in an SLR camera. With this Lume Cube 2.0 and the aforementioned older Revuenon lens, an illuminance of approximately 42,000 lux can be achieved at full power in the light field 14 with an image scale of 2:1 in a light field with a diameter of 25mm and a free distance of 95mm, which is often sufficient for amateur use even when working without a tripod. Here, too, a white light field 14 is created with the color temperature of 5600K and the Color Rendering Index (CRI) of 95 specified by the manufacturer Lume Inc. List of reference symbols 1 LED-based light source 1a LED 1b Emitting surface of the LED 1a 2 current controllers 3 accumulator for electrical supply of the LED 1a 4 light-gathering optics 4a Converging lens 5 light-condensing lens 5a Front lens of the light-condensing lens 5 5b light-collecting lens, which is arranged downstream of the iris diaphragm 6 in the light-condensing lens 5 6 Iris diaphragm in the light-condensing lens 5 6a Aperture blades 7 Lens mount of the light-condensing lens 5 8 Intermediate piece with two lens connections 9 and 10 in the design for one camera (female piece) 9 front lens connection on the intermediate piece 8 for the attachment of a light-projecting lens 11 with a support surface A9 This can be a threaded connection, a bayonet connection or a plug connection. 10 rear lens connection on the intermediate piece 8 for the attachment of a light-projecting lens 11 with a support surface A10 This can be a threaded connection, a bayonet connection or a plug connection. 11 light-projecting lens 11a Lens in the light-projecting lens 11 11b Lens mount 11a 12 lens mount 13 Iris diaphragm in the light-projecting lens 11 13a Aperture blades 14 Light field a Distance of the real image LF'' of the luminous field LF from the mount on the side of the larger lens of the light-projecting objective 11 A7 Mounting surface on the light-condensing lens 5 A9 front support surface on the intermediate piece 8 A10 rear support surface on the intermediate piece 8 A12 Contact surface of the lens mount 12 on the light-projecting lens 11 a_eff effective flange focal distance of the light-projecting lens 11 The effective flange focal distance a_eff is calculated upwards from the support surface of the lens mount A10 to the virtual light field LF'v with the point P'. a_nk nominal flange focal distance of the light-condensing lens 5 according to the manufacturer's specifications a_np nominal flange focal distance of the light-projecting lens 11 according to the manufacturer's specifications B1'v virtual image of LED 1a B1'' real image of LED 1a d1 Distance of the lens vertex S1 of the converging lens 4a from the lens vertex S2 of the front lens 5a of the light-condensing objective 5 d2 Distance between the support surface A9 and the support surface A10 on the intermediate piece 8 d3 Diameter of the lens mount 11a E Aperture plane, which is represented by the iris diaphragm 6 f1 focal length of the converging lens 4a F1 front focal point of the converging lens 4a f2 Focal length of the light-condensing lens 5 F2' rear focal point of the light-condensing lens 5 f3 Focal length of the light-projecting lens 11 F3 front focal point of the light-projecting lens 11 F3' rear focal point of the light-projecting lens 11 fS1 focal length of the converging lens 4a H1 front principal point of the converging lens 4a H2' rear principal point of the light-condensing lens 5 H3' rear principal point of the light-projecting lens 11 LF luminous field in the aperture plane E LF'v virtual image of the light field LF LF'' real image of the luminous field LF The real image of the luminous field LF represents the light field 14. LSB selected light beams OA optical axis P Center of the luminous field LF on the optical axis OA P'v Center point in the virtual image of the luminous field LF on the optical axis OA PL point on the emitting surface 1b of the LED 1a on the optical axis OA PL' real image point of the point PL PL'v virtual image point of the point PL solely by imaging by means of the converging lens 4a PL1 edge point on the emitting surface 1b of the LED 1a PL1' real image point of the edge point PL1 PL1'v virtual pixel of the edge point PL1 S1 lens vertex of the converging lens 4a S2 Lens vertex of the front lens 5a of the light-condensing objective 5 v Depth offset The depth offset is always relative to the lens mount 12 of the light-projecting lens 11 with its mounting surface A12. The depth offset v represents the difference between the effective flange focal distance a_eff and the nominal flange focal distance a_np of the light-projecting lens 11. z1 signed focal distance of the emitting surface 1b of the LED 1a from the focal point F1 of the converging lens 4a z2' signed focal distance from the focal point F2' at the light-condensing lens 5 for the real image B1'' from the emitting surface 1b of the LED 1a z3' signed focal distance from the focal point F3' at the light-projecting lens 11 for the real image LF" of the virtual light field LF'v, which is the light field 14

Claims

[1] Arrangement for lighting, especially for macro photography, for close-up moving image recordings or for inspections with an LED-based light source, with a light-collecting optic, with a light-condensing lens and with a light-projecting lens, characterized by that the LED-based light source (1) either by means of an LED (1a) or as a group of LEDs or as an LED unit or as an LED array is trained and the LED (1a) has a radiating surface (1b) with the point (PL) on the optical axis (OA) and the light-collecting optics (4) are arranged downstream of the radiating surface (1b) and the light-collecting optics (4) either with only one convex lens (4a) or is designed as a light-collecting multi-lens and the light-collecting optics (4) are designed with a focal length (f1) and a focal point (F1) and the LED (1a) with its radiating surface (1b) is arranged intrafocally to the light-collecting optics (4) and the emitting surface (1b) of the LED (1a) with the point (PL) has an intrafocal focal distance (z1) from the focal point (F1) that is greater than or equal to one tenth and less than or equal to 0.9 times the focal length (f1) of the light-collecting optics (4) and the light-collecting optics (4) are followed by the light-condensing lens (5) and the light-condensing lens (5) is formed with an iris diaphragm (6) and a light field (LF) is bordered by the iris diaphragm (6) in the light-condensing lens (5) and at least one light-collecting lens (5b) is arranged downstream of the iris diaphragm (6) in the light-condensing lens (5) and a virtual image (LF'v) in front of the iris diaphragm (6) is formed by the at least one light-collecting lens (5b) in the light-condensing lens (5) and the light-condensing lens (5) is a light-projecting lens (11) is arranged downstream and the light-projecting lens (11) is used to project the virtual image (LF'v) of the luminous field (LF) into the object space and in the object space a real image (LF") of the virtual image (LF'v) of the luminous field (LF) exists as a projected light field (14) and due to the distance of the light-projecting lens (11) from the virtual image (LF'v), an effective flange focal distance (a_eff) exists for this light-projecting lens (11), which is significantly increased by a predetermined depth offset (v) compared to its nominal flange focal distance (a_np) according to the manufacturer's specifications and the effective flange focal distance (a_eff) for the light-projecting lens (11) represents the distance of the virtual image (LF'v) in the light-condensing lens (5) from the support surface (A12) of the light-projecting lens (11) from the perspective of the light-projecting lens (11) and this effective flange focal distance (a_eff) results from the addition of the nominal flange focal distance (a_np) and a predetermined depth offset (v) determined from the focal point (F3) to the virtual image (LF'v) and the predetermined depth offset (v) is greater than or equal to 0.1 times the focal length (f3) and less than or equal to the focal length (f3) of the light-projecting lens (11) according to the specification of a lens manufacturer and the maximum lateral extent of the emission surface of the LED (1a) is less than or equal to the diameter (d3) of the mount (11b) of the lens (11a) in the light-projecting lens (11), through which the light enters the light-projecting lens (11) through this lens (11a) and the distance of the light field (14) from the light-projecting lens (11) is greater than or equal to 1.5 times the focal length (f3) of the light-projecting lens (11). [2] Illumination arrangement according to claim 1, characterized in that the light-collecting optics (4) is designed as a converging lens (4a) with a focal length (f1) between 5 mm and 100 mm. [3] Illumination arrangement according to one of claims 1 and 2, characterized in that the light-condensing lens (5) is designed as a presently or in the past commercially available and interchangeable video, film or photographic lens. [4] Illumination arrangement according to claim 3, characterized in that the light-condensing lens (5) is designed with a focal length (f2) between 5 mm and 85 mm. [5] Illumination arrangement according to claim 1 and at least one of claims 2 to 4, characterized in that the light-projecting lens (11) is designed as a commercially available and interchangeable video, film or photo lens in the present or in the past. [6] Illumination arrangement according to claim 5, characterized in that the light-projecting lens (11) is formed with a lens connection (7) which is common in the photo, film or video world. [7] Illumination arrangement according to claim 6, characterized in that the light-projecting lens (11) is designed with a focal length (f3) between 10 mm and 200 mm. [8] Illumination arrangement according to claim 1 and at least one of claims 2 to 7, characterized in that the predetermined depth offset (v) is greater than or equal to 0.3 times the focal length (f3) and less than or equal to the focal length (f3) of the light-projecting lens (11) according to the specification of a lens manufacturer. [9] Illumination arrangement according to claim 1 and at least one of claims 2 to 7, characterized in that the predetermined depth offset (v) is greater than or equal to 0.5 times the focal length (f3) and less than or equal to the focal length (f3) of the light-projecting lens (11) according to the specification of a lens manufacturer. [10] Illumination arrangement according to claim 1 and at least one of claims 2 to 9, characterized in that the light-condensing lens (5) and the light-projecting lens (11) are connected to one another by an intermediate piece (8). [11] Illumination arrangement according to claim 10, characterized in that the intermediate piece (8) is arranged with its lens connection (9) on the lens connection (7) of the light-condensing lens (5). [12] Illumination arrangement according to claim 11, characterized in that the intermediate piece (8) is formed on both sides with a lens connection (10) generally known in the photo, film or video world. [13] Illumination arrangement according to claim 1 and at least one of claims 2 to 12, characterized in that the light-condensing lens (5) is designed with a C-mount or a CS-mount lens connection. [14] Illumination arrangement according to claim 1 and at least one of claims 2 to 13, characterized in that the light-projecting lens (11) is designed with a C-mount or a CS-mount lens connection. [15] Lighting arrangement according to claim 1 and at least one of claims 2 to 14, characterized in that the LED (1a) is assigned an accumulator (3) with a current controller (2) for operation. [16] Methods of illumination, in particular for macro photography, for close-up motion picture recordings or for inspections using an LED, with a light-collecting optic and with a light-condensing lens and with a light-projecting lens, characterized by that the LED (1a) arranged intrafocally to the light-collecting optics (4) is imaged with its radiating surface (1b) by the subsequent light-collecting optics (4) and the radiating surface (1b) with the point (PL) has an intrafocal focal distance (z1) to the focal point (F1) which is greater than or equal to one tenth and less than or equal to 0.9 times the focal length (f1) of the light-collecting optics (4) and thus a virtual image (B1'v) of the emitting surface (1b) of the LED (1a) is formed by means of the light-collecting optics (4) and an imaging of the virtual image (B1'v) through the light-condensing lens (5) with formation of a real image (B1') after the light-condensing lens (5) with image position in the extrafocal near range of the light-condensing lens (5) is carried out and an iris diaphragm (6) in the light-condensing lens (5) both the opening of the light-condensing lens (5) for the light beam from the virtual image (B1'v) of the LED (1a) and the aperture stop are limited and the iris diaphragm (6) as a field diaphragm delimits a luminous field (LF) in the light-condensing lens (5) for a light-projecting lens (11) which is arranged downstream of this light-condensing lens (5), and a light-collecting lens (5b), which is arranged downstream of the iris diaphragm (6) in the light-condensing lens (5), images the luminous field (LF) and its edge to a virtual luminous field (LF'v) and the virtual light field (LF'v) is placed as a light object in front of the light-projecting lens (11) and this virtual light field (LF'v) is projected into the object space as a real image (LF'') at a significant distance from the light-projecting lens (11), which represents a light field (14) for illumination.

Images