Optical device with reduced stray light and manufacturing method thereof

Abstract

The invention relates to an optical device with reduced stray light and a manufacturing method thereof. The optical device includes: a beam shaping element made of a first material, having a base surface and a top surface opposite each other, and having a peripheral side surface connecting the base surface and the top surface to each other; and a support body made of a second material, which is formed with a container for the beam shaping element and has at least one common contact surface with the side surface of the beam shaping element. The first material and the second material are in direct contact with each other at a contact surface between the beam shaping element and the support body. The first material is permeable to defined electromagnetic radiation and the second material can absorb the defined electromagnetic radiation. Further, the first material and the second material each have a defined refractive index with respect to the defined electromagnetic radiation. The defined refractive index of the second material is set in a defined ratio to the defined refractive index of the first material so as to set a specific transition characteristic for the defined electromagnetic radiation at the contact surface.

Description

Technical Field

[0001] The invention relates to an optical device, in particular a safety light barrier, a safety light grid or a safety laser scanner, and to a corresponding method for producing such a device. Background Art

[0002] In general, an optical device is a technical device that uses electromagnetic radiation, especially light, to capture, process, manipulate or display information. Optical devices are used in many fields, such as photography, astronomy, microscopy, ophthalmology, communications, consumer electronics and many other fields. Optical devices use the properties of light such as reflection, refraction and absorption. They use lenses, mirrors, prisms and other optical components to direct and shape light. Examples of optical devices include cameras, binoculars, microscopes, telescopes, lasers, projectors, screens and optical sensors.

[0003] Optical sensors are devices that use light to measure or detect certain physical or chemical properties. They convert light signals into electrical signals, which can then be analyzed and interpreted. Optical sensors are used in many areas, such as industry, medicine, environmental monitoring, safety technology and automation. Examples of optical sensors include light barriers containing light grids or laser scanners. Light barriers have one or more light sources (transmitters) and one or more light receivers. If the light between the transmitter and the receiver is interrupted, for example by an object or a person, the sensor detects the change and emits a signal. Light barriers and light grids are often used in automation technology, access control and on machines as electro-sensitive protective equipment (ESPE).

[0004] When using ESPE (such as light barriers) on technical systems, various standards and safety regulations must be observed. For Europe, these standards and safety regulations include EN ISO 13849-1, EN 61496-1 and EN 61496-2 and EN 62046.

[0005] EN ISO 13849-1 deals with the safety of machinery and defines the requirements for safety-related control systems, including the use of light curtains as protective devices. EN 61496-1 and EN 61496-2 describe general requirements and test methods for light curtains and light barriers, including their electrical and optical properties. EN 62046 deals with the use of light curtains in machine controls and describes the requirements for the function, installation, commissioning, operation and maintenance of light curtains.

[0006] For ESPE, these standards specify, among other things, limiting the permissible aperture angles of the transmitter and receiver, i.e., in particular limiting and minimizing the influence of stray light on the system. An important source of this scattered light is the reflection and scattering of light on the walls of the housing (e.g., tube) that defines the optical channel. Light traps are a well-known method for dealing with stray light. They prevent the light beam from being reflected or scattered by the walls and reaching the detector.

[0007] As an example of such a light trap, EP 1 420 271 A2 shows an element holder as a single-piece element having a light blocking component to limit the scattering angle of light. The element holder has a cylindrical internal channel and can detachably hold an optical element at one end. A lens is attached to an opposite end of the element holder. The element holder is a molded plastic component and has a single light shielding wall molded integrally with the element holder so that it extends through the internal channel in a plane approximately equidistant from the photodetector element and the lens to limit the angle of light scattering.

[0008] DE 199 10 321 A1 shows another example of the use of light traps in light barriers or gratings.

[0009] Another way to deal with stray light is to use special filters or adapt the light source. An example of this is shown in EP 2535 741 A2. Here, a phosphor-based layer including a mixture of, for example, nanophosphors and / or quantum dot phosphors is used to filter the received light (including both the expected reflected light and the sunlight) before being received by the photodetector. Summary of the invention

[0010] Against this background, it is an object of the present disclosure to provide a new, cost-effective method for minimizing stray light.Another object is to specify a manufacturing method for an optical device which effectively implements the new, cost-effective method for minimizing stray light.

[0011] According to one aspect of the present disclosure, the problem is solved by an optical device, which includes: a beam shaping element of a first material, which has a base surface and a top surface opposite to each other, and a surrounding side surface connecting the base surface and the top surface; a support (carrier) of a second material, which forms a container (holder) for the beam shaping element and has at least one common contact surface with the side surface of the beam shaping element. The first material and the second material are in direct contact with each other at the contact surface between the beam shaping element and the support. The first material is transparent to defined electromagnetic radiation, and the second material is absorbent to defined electromagnetic radiation. In addition, the first material and the second material each have a defined refractive index (n1, n2) relative to the defined electromagnetic radiation. The defined refractive index of the second material is set to a defined ratio with the defined refractive index of the first material so as to set a specific conversion characteristic for the defined electromagnetic radiation at the contact surface.

[0012] According to another aspect of the present disclosure, the problem is also solved by a method for manufacturing an optical device comprising a beam shaping element and a support body. The method comprises: providing a first material for the beam shaping element, the first material being transparent to defined electromagnetic radiation and having a first defined refractive index relative to the defined electromagnetic radiation; providing a second material for the support body, the second material being absorbent to defined electromagnetic radiation and having a second defined refractive index relative to the defined electromagnetic radiation; forming the beam shaping element from the first material and forming the support body from the second material; joining the first material and the second material to form an integrally joined (single-piece and therefore non-destructively separable) component from the first material and the second material, wherein the beam shaping element has a base surface and a top surface opposite to each other, and a surrounding side surface joining the base surface and the top surface to each other, wherein the support body forms a container for the beam shaping element and has at least one common contact surface with the surrounding side surface of the beam shaping element, and wherein the defined refractive index of the second material is set to a defined ratio with the defined refractive index of the first material so as to set a specific transformation characteristic for the defined electromagnetic radiation at the contact surface.

[0013] Therefore, one idea is to counteract the undesired influence of stray light that may affect the optical device by selecting materials for the beam-shaping element and its support and connecting them together. To this end, at least one contact surface between the beam-shaping element and the support, at which the reflection or refraction of light is to be avoided or at least reduced, must be arranged in such a way that the material of the beam-shaping element and the material of the support are in direct contact with each other at the contact surface. Preferably, the beam-shaping element and the support are joined together during assembly in such a way that the contact surface is not in contact with the cavity and, in particular, no gaseous medium is trapped between the first material and the second material. Preferably, the first material and the second material therefore rest directly and flatly against each other at the contact surface without a third material different from the first material and the second material being arranged between them. In some preferred embodiments, the first material and the second material are joined together integrally in an injection molding process. For example, the first material can be molded onto the second material, or the second material can be molded onto the first material. In other preferred embodiments, the first material and the second material can be thermally welded together, in particular by laser welding. In principle, it is also conceivable to join the first material and the second material by dissolving with a volatile adhesive or directly sandblasting, without the need for intermediate layers of different materials to form an integral component. The beam shaping element, for example a lens, is made of a material that is transparent to defined electromagnetic radiation, in particular electromagnetic radiation in the wavelength range of visible light and / or infrared light. For its part, the support body is made of a material that absorbs electromagnetic radiation in this wavelength range, at least on the part located behind the contact surface. Furthermore, the refractive index of the materials for the beam shaping element and the support body is selected in such a way with respect to the electromagnetic radiation that certain transition characteristics are achieved at the contact surface. In particular, the refractive index is selected so that the electromagnetic radiation can enter the second material as non-reflective as possible at at least one contact surface and is subsequently absorbed by the second material as much as possible, i.e., in particular, due to the material pairing, the contact surface is largely low-reflecting and low-refractive.

[0014] It has been shown that the refractive indices of the material of the beam shaping element and the material of the support should be consistent. The ratio between the refractive indices is preferably 1. According to the Fresnel formula, in the case of having essentially the same refractive index within a certain range of incident angles, the incident light is largely not reflected and refracted when entering the support material, and can be absorbed by it. Therefore, the light irradiated onto the contact surface from this incident angle can be prevented from further propagating through the beam shaping element in a simple and effective manner. In this way, the detection of incident light or the emission of a light beam can be advantageously controlled, since the influence of scattered light can be effectively avoided or reduced. Preferably, the material for the beam shaping element and the material for the support are the same material with different absorption coefficients, i.e. the first material and the second material are based on the same base material. The materials can be processed into the support and the beam shaping element in a joint forming process.

[0015] Since the scattered light reduction is essentially provided via the materials of the support body and the beam-shaping element and their processing, the structure of the beam-shaping element and the support body can be selected essentially freely. This opens up new possibilities for making the optical device simpler, more efficient, faster to manufacture and cheaper. The object mentioned at the outset is thereby achieved.

[0016] In a further refinement, the defined ratio of the refractive indices of the support body material and the material of the beam shaping element can be between 0.9 and 1.1, preferably between 0.95 and 1.05, in particular 1.

[0017] In this arrangement, the refractive indices of the different materials used for the beam shaping element and the support are preferably identical or at least very similar in order to achieve the desired transition characteristics. This can be easily achieved by using the same base material for both components, whereby the base material is made radiation-absorbing when used for the support, for example by adding a pigment.

[0018] In a further refinement, specific transition characteristics can render the contact surface low-reflective and low-refractive, in particular non-reflective and non-refractive, for defined electromagnetic radiation coupled in via the base surface and the top surface.

[0019] Furthermore, in a further refinement, the specific transition characteristics can be such that a defined electromagnetic radiation coupled in through the base surface and the top surface within a defined range of incident angles is absorbed by the second material.

[0020] Thus, the transition characteristics which can be adjusted by the choice of material enable the contact surface to be adapted to the desired conditions, which can be specified by the structure of the beam-shaping element and / or the support body, the type of electromagnetic radiation or the type of coupling of electromagnetic radiation into the beam-shaping element. In this way, the optical device can be designed particularly flexibly.

[0021] In a further development, the first material can be a transparent plastic and the second material can be a pigmented or colored, in particular black, plastic.

[0022] Plastics can be easily molded into different shapes. The properties of plastics may also be influenced by the addition of various foreign substances. In particular, this relates to the optical properties. In addition, plastics can be processed very well in injection molding processes. For example, different plastics can be processed simultaneously and joined together in an injection molding process to form a single-piece component, thereby producing a direct seamless connection between the individual plastics. Black plastics are particularly light-absorbing. Therefore, the use of plastics as a base material advantageously simplifies the construction of the above-mentioned optical devices.

[0023] In a further improvement, the plastic used for the first material and / or the second material may include or consist of polycarbonate (PC), polymethyl methacrylate (PMMA), cyclic olefin copolymer, optical polyester or polysulfone. PMMA or polymethyl methacrylate is also known as acrylic glass or resin glass. PMMA is a transparent thermoplastic polymer formed from methyl methacrylate monomer units, characterized by high light transmittance and optical transparency. It is almost colorless to the human eye and has a transparency similar to that of glass, but is lighter in weight. Therefore, using PMMA as a base material is beneficial to the optical properties of the optical device. Polycarbonate is preferred in some embodiments because it has good mechanical properties, such as elongation at break and impact strength. The polycarbonate substrate allows connection options, such as snap hooks or cold stamping points, which are difficult to achieve with PMMA.

[0024] The beam-shaping element and the support body can be designed as one-piece, ie as integrally joined parts, and formed by a multi-component injection molding process, for example a cascade injection molding process or a sandwich injection molding process.

[0025] A one-piece component consisting of at least two integrally joined components simplifies the assembly of the optical device and allows its cost-effective manufacture. The multi-component injection molding process achieves a seamless connection between the materials used in a proven automated manufacturing process in a very efficient manner. This ensures that the effects of the material selection mentioned above (adjustment of the refractive index) occur at the contact surfaces, since no other media are trapped between the materials. In addition, injection molding generally allows very flexible shaping. In principle, however, the one-piece component can also be manufactured in another way, for example using a laser welding process, by which the beam shaping element and the support body are integrally joined to form the one-piece component.

[0026] In a further refinement, the container is funnel-shaped and tapers in a direction from the top surface to the base surface.

[0027] According to this design, the container can be funnel-shaped, which allows to advantageously reduce the size of the beam-shaping element. A funnel-shaped design is usually not suitable for reducing scattered light, but due to the special choice of material it can be used here, thereby achieving the above-mentioned size reduction. Reducing the size of the beam-shaping element helps to save material and minimize the possibility of forming air holes in the body of the element, as the overall volume of the beam-shaping element becomes smaller. Therefore, this arrangement also contributes to a cost-effective and optimized design of the optical device.

[0028] In a further refinement, the container can surround at least a portion of the base surface with at least one opening for confined electromagnetic radiation, the opening being designed as an aperture for an optoelectronic element (e.g., a photoelectric emitter or detector) in the beam path. In a further refinement that can be implemented alternatively or additionally, the container forms a tube protruding from the top surface.

[0029] According to this design, by realizing one or more optical apertures in the beam path of the optical device directly through the support body, further elements and manufacturing steps can be omitted. In some preferred embodiments, the support body forms an aperture stop in the beam path. Furthermore, the support body can form an aperture which defines the resolution of a grating with a large number of light beams running parallel to each other. In a particularly preferred embodiment, the beam shaping element and the receiver form a one-piece component which realizes the optical lens and the tube with the resolution-defining aperture. All these variants contribute to further cost savings in the manufacture of optical devices, in particular optical devices in the form of safety light barriers or safety light grids.

[0030] The aperture may be filled with the material of the beam shaping element.

[0031] This design facilitates the joining of the support body and the beam-shaping element into a single-piece component and simplifies its manufacture. This improvement therefore also contributes to further cost savings. A further advantage of this design is that, due to the two-component (2K) injection molding manufacturing process, the lens axis and the pinhole axis (tube) are located very precisely on each other and the deviation from the ideal optical axis can be kept very small. This improves the usability and alignability of the grating.

[0032] In a further refinement, a protruding structure is formed in the container that acts as a light trap.

[0033] For example, the structure may include stair-like steps, serrated protrusions and / or a large number of high comb-shaped walls. As explained at the beginning, light traps are already known. However, this embodiment can be particularly advantageously combined with specific transition properties at the contact surface between the first material and the second material, because the advantageous effect of the specific transition properties is particularly effective at small incident angles of the defined electromagnetic radiation, while light traps are particularly effective at larger incident angles.

[0034] In a further development, the optical device has a plurality of beam-shaping elements, each beam-shaping element of the plurality of beam-shaping elements having its own receptacle in the support body.

[0035] In this refinement, multiple beam shaping elements can be formed simultaneously with the support body, which advantageously simplifies the manufacture of special optical devices such as gratings having multiple optical elements.

[0036] In a further development, the optical device is an optical sensor, in particular a safety light barrier or a laser scanner, which meets the safety requirement level SIL 3 according to IEC 61508 / IEC 61511 or the performance level PLd according to EN ISO 13849-1.

[0037] As mentioned before, optical sensors are devices that use light to measure or detect certain physical or chemical properties. They convert optical signals into electrical signals, which can then be analyzed and interpreted. For optical sensors, it is particularly important that only dedicated light triggers the detection and that unwanted stray light is avoided, which could lead to false triggering or, worse, could hinder the detection of safety-related objects. This can be advantageously achieved by the above-mentioned design, so that an optimized optical sensor can be realized.

[0038] In a further refinement, the optical device may be a grating.

[0039] For example, a light grid has many optical elements that work together to produce an electro-sensitive protective device (ESPE), i.e. a contactless protective device. Since many optical elements corresponding to the configuration shown above can be realized in a simple manner, a light grid can be realized in this way in a particularly cost-effective manner.

[0040] It is understood that the features mentioned above and those explained below can be used not only in the combination indicated in each case but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Examples of implementations of the invention are shown in the drawings and are explained in more detail in the following description.

[0042] FIG. 1 shows a schematic cross-sectional view of an optical arrangement with a light trap for minimizing stray light, according to the prior art.

[0043] Figure 2 A schematic cross-sectional view of an optical device with passive optoelectronic elements according to an embodiment of the present disclosure is shown.

[0044] Figure 3Shown according to Figure 2 Schematic cross-sectional view of an optical device with active optoelectronic elements according to an embodiment of the present invention.

[0045] Figure 4A The plan view shows the Figure 2 Schematic cross-sectional view of another variant of an embodiment of.

[0046] Figure 4B The cross-sectional view shows the Figure 2 Schematic cross-sectional view of another variant of an embodiment of.

[0047] Figure 4C The cross-sectional view shows the Figure 2 Schematic cross-sectional view of another variant of an embodiment of.

[0048] Figure 5 The cross-sectional view shows the Figure 2 Schematic cross-sectional view of another variant of an embodiment of.

[0049] Fig. 6A The cross-sectional view shows the Figure 2 Schematic cross-sectional view of another variant of an embodiment of.

[0050] Figure 6B The cross-sectional view shows the Figure 2 Schematic cross-sectional view of another variant of an embodiment of.

[0051] Fig. 7A An application example of the optical device of the present disclosure is shown in a perspective view.

[0052] Figure 7B Shows Fig. 7A A plan view of an application example is shown in FIG.

[0053] Figure 7C Shows Fig. 7A A side view of an application example is shown in FIG.

[0054] Fig.7D Along Figure 7C The cross-sectional view along the line CC' in FIG. 1 shows the Fig. 7A Application examples.

[0055] FIG. 8A to FIG. 8C A variant with an additional light trap inside the support is shown. DETAILED DESCRIPTION

[0056] FIG. 1 shows an optical arrangement 1 corresponding to the prior art with a light trap for minimizing stray light.

[0057] In the embodiment shown, the optical device 1 from the prior art consists of three separate parts, namely a beam-shaping element (lens) 2, a support 3 in the form of a tube and an optoelectronic element 4. Electromagnetic radiation, in particular light, is coupled into the optical device via the beam-shaping element 2. The tubular support 3 forms a light channel through which the coupled light is guided to the optoelectronic element 4. A light trap is formed inside the tubular support 3, which prevents some of the incident light, in particular light reflected from the tube wall, from reaching the optoelectronic element 4. The light trap 5 reduces the influence of stray light on the detection performed by the optoelectronic element 4.

[0058] Figure 2 An optical device according to an embodiment of the present disclosure is shown.

[0059] The optical device as a whole is here denoted by reference numeral 10. Similar to the optical devices of the prior art, the optical device 10 also has a beam-shaping element 12 and a corresponding support 14. In addition, an optoelectronic element 16 can be provided, which in this example is designed as a detector for electromagnetic radiation, in particular light. In other embodiments, the optoelectronic element can include an emitter for electromagnetic radiation, in particular light in the visible and / or infrared range. Such an emitter is referred to as an active element and the detector as a passive optoelectronic element hereinafter.

[0060] The support body 14 is designed as a container 18 or has at least one such container, in which the beam shaping element 12 is mounted. The beam shaping element 12 has a base surface 20, a top surface 22 opposite the base surface, and a side surface 24 connecting the base surface and the top surface. The beam shaping element 12 can be a homogeneous body with a uniform composition and structure, i.e., the material properties such as density, chemical composition and physical properties can be the same in each part of the body.

[0061] As shown here, the container 18 for the beam shaping element 12 can be designed as a tube, the free end of which protrudes beyond the top surface 22 and thus forms an aperture. In a light barrier, a grating or a laser scanner, this aperture can define the resolution with which the optical device can detect objects. However, the form of the container 18 is not limited to this. The beam shaping element 12 accommodated in the container 18 has at least one common contact surface 26 with the support body 14. Here, the contact surface 26 is a part of the side surface 24. In various embodiments, the contact surface 26 can also include the entire side surface 24 and a part of the base surface 20. The top surface 22 or at least a part of it is exposed from the support body 14. Electromagnetic radiation can be coupled into the optical device 10 from the outside via the top surface 22 ( Figure 2 ), or electromagnetic radiation may be emitted from the optical device 10 via the top surface 22 (see Figure 3 ).

[0062] In the example shown, the optical axis 28 of the optical device 10 extends along a first direction (hereinafter referred to as the x-direction). The base surface 20 and the top surface 22 of the beam shaping element 12 are transverse, in particular perpendicular to the x-direction. The side surface 24 can in turn be a surface that is rotated around the optical axis 28 or a surface composed of a plurality of side surfaces, which together connect the base surface 20 and the top surface 22. In the example shown, the side surface has a first side surface and a second side surface, which extend transversely, in particular vertically, in a second direction (hereinafter referred to as the y-direction) perpendicular to the first direction. The first side surface and the second side surface are part of the contact surface 26 with the support 14 here. The top surface 22 may not be in contact with the support 14 in the x-direction. Electromagnetic radiation is coupled into the optical device 10 from the outside or emitted via the top surface 22. The base surface 20 is opposite to the top surface 22 and is at least partially covered by the support 14. An opening (aperture) 30 may be provided in the base surface 20, through which electromagnetic radiation may be emitted to the optoelectronic element 16, or through which the optoelectronic element 16 may couple radiation into the beam shaping element 12. The opening 30 may also perform other optical functions, such as acting as an aperture stop. In a third direction perpendicular to the first direction and perpendicular to the second direction (hereinafter referred to as the z-direction), the beam shaping element 12 may also be surrounded by the support 14, so that these parts may also be part of the contact surface 26.

[0063] The material forming the beam shaping element 12 (first material) and the material forming the support 14 (second material) are selected or prepared in a specific way so as to achieve defined transformation characteristics of the electromagnetic radiation propagating through the beam shaping element 12 at the contact surface 26. Thus, the first material is a material that is transparent to electromagnetic radiation, preferably colorless, with a transparency similar to glass. On the other hand, the second material is an opaque material that absorbs electromagnetic radiation. The second material absorbs electromagnetic radiation to the greatest extent possible. Therefore, the second material is preferably black.

[0064] The beam shaping element 12 is integrated into the container 18 in such a way that the first material seamlessly abuts the second material at least on a common contact surface 26. According to the Fresnel formula, the transition characteristics at the contact surface 26 are essentially determined by the refractive indices (n1, n2) of the first material and the second material. In order to achieve the lowest possible reflection and refraction transition characteristics at the contact surface, the refractive indices (n1, n2) of the first material and the second material are the same or at least similar (n1≈n2) within a narrow tolerance range (e.g. less than 5%). In this case, the light rays impinging on the contact surface 26 (at least within a limited range of incident angles) are not refracted or reflected at the contact surface, or are refracted or reflected only to a small extent, but almost completely enter the second material of the support body 14 and are absorbed there.

[0065] Unwanted scattered light coupled into the beam shaping element 12 through the top surface 22 at an angle to the optical axis 28 (illustrated here by arrow 32) is not reflected onto the optoelectronic element 16 at the contact surface 26 as is usually the case and indicated here by arrow 34, but is absorbed by the material of the support 14. This prevents the unwanted scattered light from reaching the optoelectronic element 16 and causing false detections. Figure 2 The optical device can be implemented without the light trap shown in FIG. 1 or the filter mentioned in the introduction of the specification. However, in other embodiments, the optical device can have additional structures in the container 18 that serve as light traps. These structures can be, for example, stepped steps ( Fig. 8A ), concentric walls that rise from the base surface 20 like a comb in cross section ( Figure 8B ), or a serrated protrusion on the inner wall of the container 18 ( Figure 8C ). Thus, minimization of scattered light can be achieved only by a suitable choice of material and a seamless arrangement of the beam-shaping element 12 in the receptacle 18 of the support body 14 or in addition to the light trap.

[0066] In order to achieve a specific material selection and the desired seamless arrangement of the beam shaping element 12 in the support body 14, the optical device 10 can advantageously be realized by injection molding. Injection molding makes it possible to connect two materials (especially plastics) in such a way that the joint is seamless and generally inseparable. Injection molding, in which at least two materials are combined to form a single-piece component, is also referred to as two-component (2K) or multi-component injection molding. Various two-component injection molding processes can be used. These include cascade injection molding and sandwich injection molding. In cascade injection molding, a first component is injected into an injection mold and then a second component is injected onto the first component. The mold is generally designed so that the second component flows into the cavity of the first component and forms a tight bond. In sandwich injection molding, two components are injected into the mold simultaneously, with one component surrounding the other component.

[0067] The beam shaping element 12 can be one component and the support body 14 can be another component. It is not important which component is the first component and which is the second component. Depending on the desired application and the required structure of the optical device 10, the beam shaping element 12 can be injected onto the support body 14 during injection molding, and the support body 14 can also be injected onto the beam shaping element 12 during injection molding. Preferably, the beam shaping element 12 (lens) is injected first and then the surrounding tube 14, because in this case the tube shrinks onto the lens during cooling.

[0068] Furthermore, since multi-component injection molding processes are generally designed for the use of different materials, the material selection required to achieve the desired effect is also facilitated by the use of an injection molding process. The starting material for the beam shaping element 12 and the support body 14 is preferably the same material, in particular a plastic, such as polycarbonate or PMMA. In order to adjust the required absorption capacity of the second material, the common starting material for the support body 14 can be provided with a pigment to achieve a high absorbance for electromagnetic radiation. Although the modification achieves a high absorbance, the refractive index remains unchanged by this modification of the starting material, so that the first material and the second material have essentially the same refractive index. The starting material (first material) and the modified starting material (second material) can then be injection molded in a manner known per se to form a one-piece component having the above-described structure and material properties.

[0069] The use of a common base material also has the advantage that temperature influences act uniformly on both components, so that stresses between the individual components (in this case, the beam-shaping element 12 and the support body 14 ) can advantageously be avoided.

[0070] Figure 3 Shown according to Figure 2 An optical device having an active optoelectronic element 16 ′ according to an embodiment of the present invention.

[0071] according to Figure 3 The optical device 10 is similar to the one according to Figure 2. The embodiments differ here only with respect to the optoelectronic element 16', which in the present embodiment is an active element. The active element 16' is designed to emit electromagnetic radiation and couple it into the beam-shaping element 12, whereby most of the radiation coupled in by the optoelectronic element 16' propagates through the beam-shaping element 12 and radiates outwardly via the top surface 22. However, as indicated by the beam 36, some radiation may also impinge on the contact surface 26 between the beam-shaping element 12 and the support 14. Depending on the special design of the support 14 and the beam-shaping element 12, this radiation is also absorbed as completely as possible by the support 14, so that no reflection or only a slight reflection occurs, as indicated here by the beam 38.

[0072] Advantageously, the described structure can therefore also improve the radiation characteristics of the optical device 10. It should be understood that Figure 2 and Figure 3 The designs shown can also be combined. For example, a so-called transceiver grating has a number of optoelectronic elements on each side of the grating, which alternately contain transmitters or receivers.

[0073] Figure 4A , Figure 4B and Figure 4C Each shows from different perspectives Figure 2 Schematic diagram of another variant of the implementation method.

[0074] Figure 4A shows a plan view along the x direction, Figure 4B and Figure 4C Each shows a cross-sectional view along the z direction and along the y direction, as can be seen from the reference system and section lines shown. Figure 2 The same part.

[0075] In this embodiment, the cross-section of the beam shaping element and the container 18 of the support 14 is elliptical, i.e. the dimension of the beam shaping element 12 in the y direction is smaller than the dimension in the z direction. In this view, the container 18 of the support 14 surrounds the beam shaping element in the shape of a ring. The wall thickness of the container 18 is small relative to the width and length of the beam shaping element 12. Depending on the application or the manufacturing process, the wall thickness can be uniform or non-uniform, in particular in the case of structures that act as light traps (see Figure 8C ). Figure 4A , Figure 4B and Figure 4C The design of the optical device shown in is advantageous because the injection molding process is facilitated by the thinner shape due to the reduced wall thickness.

[0076] Figure 5 The side view shows the Figure 2sectional view of another variation of an embodiment of the invention.

[0077] Compared with the previous implementation, Figure 5 In the present embodiment, the container 18 of the support 14 is funnel-shaped. Therefore, the opening width of the top surface 22 of the beam-shaping element 12 is greater than the opening width of the container 18 on the side of the base surface 20. Funnel-shaped designs are generally undesirable in devices of the prior art, because in this shape, light may be reflected and scattered at the inner surface of the container 18 towards the optoelectronic element. However, due to the form of the beam-shaping element 12 and the support 14, i.e. the choice of materials and their joining, in this case there is little or no scattering or reflection at the contact surface 26, making the described advantages particularly effective.

[0078] In many cases, the funnel-shaped design facilitates the removal of the injection molded part from the injection mold and may therefore be desirable. In addition, the funnel-shaped design has the advantage that the volume of the beam shaping element 12 can be reduced and thus the occurrence of pores can be advantageously reduced. In addition, due to the smaller volume, less material is required for the beam shaping element 12.

[0079] Fig. 6A and Figure 6B The side view shows the Figure 2 Cross-sectional views of two further variants of the embodiment.

[0080] If already targeted Figure 2 and Figure 3 As described, the container 18 of the support 14 can have an opening 30 on the base surface 20, which opening 30 serves as a stop, for example. The opening 30 can be formed in different ways. On the one hand, Fig. 6A As shown, the opening 30 can remain open while Figure 6B , the opening 30 is filled with the material (first material) of the beam shaping element 12. Depending on the application or the manufacturing process, both variants are advantageous and are equally feasible in an injection molding process. However, the latter variant is particularly suitable for an injection molding process in order to achieve a good bond between the support body 14 and the beam shaping element 12.

[0081] Fig. 7A An application example of the optical device of the present disclosure is shown in a perspective view. Figure 7B The plan view shows the Fig. 7A Application examples, Figure 7C The side view shows the Fig. 7A application examples, and Fig.7D Along the Figure 7C The cross-sectional view along the line CC' shows the Fig. 7A Application examples.

[0082] This application example relates to a grating 40, whose substrate 42 is FIG. 7A to FIG. 7D . The base body 42 is a one-piece component formed by injection molding from two components. The first component is the support body 14 and the second component is the beam-shaping element 12. More precisely, the second component here has ten beam-shaping elements 12a to 12j, each of the ten beam-shaping elements 12a to 12j being mounted in a corresponding container 18a to 18j of the support body 14. As described above, the material of the support body (second material) and the material of the beam-shaping element 12 (first material) are selected in such a way that reflections and refractions in the container 18 are avoided or reduced.

[0083] In addition to the containers 18a to 18j, the support body 14 can also serve as a base frame for the grating 40. The beam-shaping elements 12a to 12j can also have further structures, such as connecting webs 44 between the beam-shaping elements and, if necessary, further light guides 46 for other tasks. Thus, further components present in the grating, such as status indicators in the form of LEDs, can advantageously be realized by a single-piece component together with the support body 14 and the beam-shaping elements 12. In this way, the grating 40 can be realized in a cost-effective manner. In particular, the assembly effort can be significantly reduced.

[0084] Fig.7D As shown in Figure 7C The section through the line CC' of the beam-shaping element 12 corresponds to the schematic diagram of the embodiment of the aforementioned figures and shows the combination of features described therein in each case. The container 18 for the beam-shaping element 12 is therefore pot-shaped, wherein the beam-shaping element 12 extends more in the y direction than in the z direction and is thus as narrow as possible in the z direction. Furthermore, the side walls of the container 18 which form the contact surface 26 between the support 14 and the beam-shaping element 12 are inclined at an angle relative to the x direction, which in turn forms the optical axis 28. The container is therefore slightly funnel-shaped with the characteristics described above for Figure 5 Said advantages are particularly relevant with regard to the removal of the container from an injection mold (not shown here). Finally, on the side of the base surface 20 of the beam shaping element, an opening 30 is provided in the container 18 as an optical aperture. However, on the opposite side (the side of the top surface 22), the beam shaping element is not in contact with the support 14, in particular from Fig. 7A It can be seen from the stereogram.

[0085] As already mentioned, the substrate 42 for the grating 40 can be manufactured by two-component injection molding. The method starts with the selection of a first material for the support body 14 and a second material for the beam shaping element 12, or the preparation of a common base material for the first material and the second material, for example by coloring the base material. The first material for the beam shaping element 12 is transparent to defined electromagnetic radiation (in particular light relevant to the application). The second material for the support body absorbs this electromagnetic radiation or is made to absorb this radiation. The two materials have the same refractive index relative to the electromagnetic radiation or have similar refractive indices within a tolerance range (n1≈n2). This is preferably achieved by using a common base material.

[0086] The first material and the second material are then filled into an injection molding machine designed for multi-component injection molding, and the injection molding process is started.

[0087] Depending on the process, the first material and the second material are injected into the injection mold simultaneously or one after another. The injection mold is FIG. 7A to FIG. 7D The negative mold of the base body 42 is shown. Depending on the process, the support body 14 can be molded first and then the beam shaping element 12 can be injection molded onto the support body 14. However, it is also conceivable to first form a plurality of beam shaping elements 12a to 12j including the connecting webs 44 and the optional light guides 46 and then overmolding this structure with the support material.

[0088] In principle, the choice of the injection molding process depends only on the desired shape of the base body, as long as the common contact surface 26 in the container 18 is seamless between the beam shaping element 12 and the support body 14 so that the aforementioned optical properties, in particular the absorption of scattered light by the support body 14, can occur.

[0089] The base body 42 after injection molding comprises at least the support body 14 and the beam-shaping element 12. For a functional grating, essentially only the electronics with optoelectronic components and external connections and the enclosed housing need to be added. Compared to conventional gratings in which separate components are used for the support body and the beam-shaping element, the assembly effort and the associated production costs can be significantly reduced.

[0090] FIG. 8A to FIG. 8C A variant of an optical device 10 of the type described above is shown, in which additional light traps 50 a , 50 b and 50 c are each provided within the support body 14 .

[0091] The scope of protection of the present invention is determined by the accompanying claims and is not limited by the features described in the description or shown in the drawings.

Claims

1. An optical device (10), comprising: A beam-shaping element (12) made of a first material, the beam-shaping element (12) having a base surface (20) and a top surface (22) opposite to each other, and having a peripheral side surface (24) connecting the base surface (20) and the top surface (22) to each other; a support body (14) made of a second material, said support body (14) forming a container (18) for said beam-shaping element (12) and having at least one common contact surface (26) with said side surface (24) of said beam-shaping element (12), wherein the first material and the second material are in direct contact with each other at the contact surface (26) between the beam shaping element (12) and the support body (14), wherein the first material is transmissive to defined electromagnetic radiation and the second material is absorbing the defined electromagnetic radiation, wherein the first material and the second material each have a defined refractive index (n1, n2) relative to the defined electromagnetic radiation, and Therein, the defined refractive index (n2) of the second material is arranged in a defined ratio to the defined refractive index (n1) of the first material in order to set a specific transition characteristic for the defined electromagnetic radiation at the contact surface (26).

2. The optical device according to claim 1, wherein: The defined ratio n1 / n2 is between 0.9 and 1.

1.

3. The optical device according to claim 1, wherein: The limiting ratio n1 / n2 is 1.

4. The optical device according to claim 1, wherein: The specific transition characteristics make the contact surface (26) low-reflective and low-refractive for the confined electromagnetic radiation coupled in through the base surface (20) and the top surface (22).

5. The optical device according to claim 4, wherein: The specific transition characteristics render the contact surface (26) non-reflective and non-refractive.

6. The optical device according to claim 1, wherein: The specific transition characteristic causes the defined electromagnetic radiation coupled in through the base surface (20) and the top surface (22) within a defined range of incident angles to be absorbed by the second material from the contact surface (26).

7. The optical device according to claim 1, wherein: The first material is a first transparent plastic and the second material is a second colored plastic that absorbs the confined electromagnetic radiation.

8. The optical device according to claim 7, wherein: The second material is black plastic.

9. The optical device according to claim 7, wherein: The first transparent plastic and the second colored plastic each include polycarbonate, polymethyl methacrylate, cyclic olefin copolymer, optical polyester or polysulfone.

10. The optical device according to claim 1, wherein: The beam shaping element (12) and the support body (14) are integrally joined components.

11. The optical device according to claim 1, wherein: The container (18) is funnel-shaped and gradually narrows in a direction from the top surface (22) to the base surface (20).

12. The optical device according to claim 1, wherein: The container (18) surrounds at least a portion of the base surface (20) with at least one opening (30) for the defined electromagnetic radiation, wherein the opening (30) is designed as a stop for a photoelectric element (16) in the beam path.

13. The optical device according to claim 12, wherein: The opening (30) is filled with the first material of the beam shaping element (12).

14. The optical device according to claim 1, wherein: The container (18) forms a tube protruding from the top surface (22).

15. The optical device according to claim 1, wherein: A protruding structure is formed in the container (18) to act as a light trap.

16. The optical device according to claim 1, wherein: The optical device comprises a plurality of beam-shaping elements (12a to 12j), each of the plurality of beam-shaping elements (12a to 12j) having its own container (18a to 18j) formed in the support body (14).

17. The optical device according to claim 1, wherein: The optical device is a safety light barrier or a safety laser scanner.

18. A method for manufacturing an optical device (10), the optical device (10) having a beam shaping element (12) and a support (14), the method comprising the following steps: - providing a first material for the beam shaping element (12), the first material being transparent to a defined electromagnetic radiation and having a first defined refractive index (n1) relative to the defined electromagnetic radiation; - providing a second material for said support (14), said second material being capable of absorbing said defined electromagnetic radiation and having a second defined refractive index (n2) relative to said defined electromagnetic radiation; - forming the beam-shaping element (12) from the first material and forming the support body (14) from the second material; - joining the beam shaping element (12) and the support body (14) to form an integrally joined component made of the first material and the second material, wherein the beam shaping element (12) has a base surface (20) and a top surface (22) facing each other, and a peripheral side surface (24) connecting the base surface (20) and the top surface (22) to each other, wherein the support body (14) is formed with a container (18) for the beam-shaping element (12) and has at least one common contact surface (26) with the surrounding side surface (24) of the beam-shaping element (12), wherein the second defined refractive index (n2) of the second material is arranged in a defined ratio to the first defined refractive index (n1) of the first material in order to set specific transition characteristics for the defined electromagnetic radiation at the contact surface (26).

19. The manufacturing method according to claim 18, wherein: The manufacture and assembly involves injection moulding.

20. The manufacturing method according to claim 19, wherein: The injection molding is multi-component injection molding.

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