Optical system for a periscope camera module and periscope camera module

Abstract

An optical system for a camera module (1) comprising an image sensor (7) and an optical arrangement defining a beam path (9), wherein in the beam path (9) the optical components contained therein are arranged in the following order in front of the image sensor (7): (a) a first prism (2), (b) optionally a first planar optical element (3), (c) an optical lens system (4), and (e) optionally a second prism (6), wherein at least component (a) comprises at least one absorption filter.

Description

[0001] The present invention relates to an optical system for a camera module, in particular for a periscope camera, comprising an optical arrangement and an image sensor.

[0002] So-called periscope cameras are sometimes built into smartphones and consist of a reflective prism that captures the image to be photographed through an opening on the back of the smartphone, deflects it by 90°, focuses it, and then forwards it via an optical arrangement to the sensor, which captures the data. The optical arrangement typically also includes an optical lens system (also called a lens) and optionally another prism, which causes a further 90° deflection onto the sensor.

[0003] The general design of optical systems for such periscope cameras is described in detail, for example, in US 10,908,387 B2 and US 2021 / 0124145 A1. US 2021 / 0026117 A1 discloses an optical system comprising a first prism that deflects the incident light by 90°, a lens system, and a second prism that causes a further 90° deflection of the light beam. The light is then passed through an infrared blocking filter—hereafter referred to as the "IR blocking filter"—before reaching the image sensor. US 2021 / 0141206 A1 also describes a periscope camera module with a planar absorption filter positioned directly in front of the sensor. US patent 2021 / 0063687 A1 describes an optical system in which the incident light beam is first deflected by a prism before being guided to the sensor by a lens system.The described camera module can contain an absorption filter positioned in front of the sensor, with a second prism located between the sensor and the absorption filter. In the camera module described in US 2018 / 0017767 A1, the planar absorption filter is also positioned directly in front of the sensor. US 2019 / 0243112 A1 describes a camera module in which the planar absorption filter is arranged in the optical path after the lens system.

[0004] WO 2018 / 180269 A1 discloses a camera module in which the incident light passes through a first deflecting element, e.g., a prism, and through a lens system to a second deflecting element. The second deflecting element, for example, a prism, is connected to a planar optical component which acts as an absorption filter.

[0005] Due to their general design, such periscope cameras include one or two more optical components compared to conventional smartphone cameras.

[0006] The installation of IR blocking filters is necessary in both periscope cameras and conventional digital color camera systems. Image sensors are known to typically exhibit the property that their pixels are also sensitive in the infrared spectral range. Furthermore, the optics of camera modules whose optical components are made of common glass or plastics generally still exhibit some infrared transmission. However, infrared light reaching the sensor has detrimental effects on image quality, as it can lead to color and brightness distortions.

[0007] For this reason, camera modules are typically equipped with IR blocking filters, which are usually placed directly in front of the sensor. IR blocking filters are, for example, interference filters or filter glass designed to prevent infrared light from reaching the sensor. Suitable blocking filters exhibit high transmission in a first wavelength range (passband), for example, from 430 to approximately 650 nm, and very low transmission in another wavelength range, e.g., above 700 nm. Furthermore, filters with a steep cutoff, i.e., a rapid drop in transmission to the UV range below 400 nm, can also be used. Blocking the UV range is advantageous here to ensure better color recognition.

[0008] As explained above, IR blocking filters are typically placed directly in front of the sensor. Due to the ever-shrinking components of electronic devices, such as smartphone cameras, the demand for very thin filters is increasing. Thicknesses of 0.1 to 0.3 mm are common. To achieve sufficient filtering effect, the components, such as filter glass, must be more heavily colored with the coloring agent (e.g., CuO). This can have several disadvantages. These include problems in the production of glass with a high CuO content, as CuO not only acts as a coloring agent but also affects the glass structure and other physical properties. Furthermore, such filters can have a poor signal-to-noise ratio and lead to reduced image quality.Furthermore, such very thin filter elements naturally exhibit comparatively low mechanical stability.

[0009] The task is therefore to provide an optical system for a camera module that at least partially eliminates the disadvantages of previous camera modules.

[0010] The problem is solved by the subject matter of the patent claims.

[0011] The solution is achieved in particular by an optical system for a camera module (1) comprising an image sensor and an optical arrangement defining a beam path, wherein the optical components contained therein are arranged in the following order in front of the image sensor in the beam path: (a) a first prism, (b) optionally a first planar optical element, (c) an optical lens system, (e) optionally a second prism, wherein at least component (a) comprises at least one absorption filter.

[0012] The invention further relates to a periscope camera module comprising the optical system according to the invention.

[0013] It was found that such an optical system overcomes the disadvantages of known systems. For example, it eliminates the need to place an absorption filter, such as an IR blocking filter, directly in front of the image sensor. Instead, a component with the appropriate absorption effect can be positioned within the camera module where it can be larger. This results in a longer beam path through this absorbing component than through conventional, very thin filters. This, in turn, allows the use of a filter with advantageous properties regarding the blocking-to-transmission ratio, the so-called signal-to-noise ratio.

[0014] To describe the relationship between transmission and blocking, for example for an IR blocking filter, the following difference is defined: ΔΘ=log10(log10(1τi, min NIR))−log10(log10(1τi, min VIS)) where τ i, min NIR is the minimum retransmission in the near-infrared range (700 nm to 1100 nm) τ i, maxVIS ΔΘ is the maximum pure transmission in the visible range (430 nm to 565 nm). ΔΘ is the difference in spectral diabaticity as defined in ISO 23364:2021-04 and DIN 58131:2016-11.

[0015] For very thin absorption filters, a blocking filter, such as a filter glass, must be heavily doped, for example with a color-imparting component like CuO, to achieve a high degree of blocking of the unwanted radiation. However, such highly doped filter glasses exhibit a comparatively low ΔΘ, and therefore an unfavorable signal-to-noise ratio.

[0016] Absorption filters, e.g., filter glasses, with lower doping levels exhibit a significantly higher ΔΘ. However, due to the low doping, sufficient blocking of unwanted radiation requires the use of absorption filters with a large filter thickness, which are unsuitable for current smartphone cameras due to their size. It has been found that this problem is solved by the optical system according to the invention by eliminating the need for a necessarily very thin absorption filter directly in front of the image sensor and instead incorporating one or more components with a corresponding blocking effect at another position in the optical arrangement, which can have a greater thickness due to the space available there.Thus, deflecting prisms, which according to one embodiment of the invention are made from an absorbing filter material such as blue glass, have a significantly longer optical path than conventional absorption filters placed in front of the sensor. While currently standard absorption filters are only 0.1 mm to 0.3 mm thick, the optical path length through a filtering prism can be several millimeters. A similar situation exists for embodiments in which at least one planar optical element is used as a blocking filter, which, due to its position, can have a greater thickness, for example, at least 0.5 mm. This results in a higher ΔΘ for the absorption filter-comprising components according to the invention, and therefore also an optimized signal-to-noise ratio.

[0017] Preferably, at least one of the optical components (a), (b), (d), and (e) has a ΔΘ of more than 2.0, preferably more than 2.2, and particularly preferably more than 2.4 and also preferably more than 2.5.

[0018] The term "ray path" as used in the present invention refers to the sum of all ray paths that pass through the optical arrangement to the image sensor and contribute to the generation of the image. The optical components of the optical arrangement according to the invention are arranged such that the light directed to the sensor passes through these optical components.

[0019] The optical system according to the invention comprises at least one first prism which deflects the incident light to the extent required for the optical design, preferably by 90°, and directs it towards the optical lens system. After passing through the lens system, it can be directed by a second prism by a further 90° onto the image sensor or directed directly onto it. The first and second prisms according to the present invention are beam deflection elements, preferably triangular prisms or prisms in a shape based on a triangular prism. In an advantageous embodiment, the optical system comprises only one first prism to ensure the most compact and space-saving design possible for the camera module.Furthermore, the optical system according to the invention can include further optical components, in particular a first and / or a second planar optical element, preferably a first or a second planar optical element, and most preferably a first planar optical element. The first planar optical element is placed in the beam path between the first prism and the lens system, and the second planar optical element is installed in the beam path between the optical lens system and the optional second prism, or alternatively between the optical lens system and the image sensor. In these embodiments, the first and / or the second planar optical element comprises at least one absorption filter.

[0020] In a preferred embodiment, the optical arrangement according to the invention comprises only one planar optical element, preferably a first planar optical element. This offers several advantages. Firstly, the space requirement of the camera module is reduced, and secondly, the manufacturing costs are lower compared to an arrangement with two planar components. Furthermore, optical problems that can arise when optical elements are integrated into the arrangement downstream of the lens system can be avoided. These optical problems can occur because these additional optical components must be considered in the design of the optical lens system. This applies analogously to the optional second prism.

[0021] According to the invention, at least component (a) comprises at least one absorption filter. In some advantageous embodiments, two or more, for example two, three or four, of the aforementioned optical elements (a), (b), (d) and (e) may also comprise at least one absorption filter.

[0022] Absorption filters according to the present invention are optical elements which are arranged in the beam path so that light rays detected by the sensor pass through this element, wherein the transmission of the optical element with respect to the wavelength that interferes with image generation is significantly lower than for other wavelengths which are to reach the sensor.

[0023] Preferably, the at least one absorption filter is an IR blocking filter, more preferably an NIR blocking filter and / or a UV blocking filter, and most preferably an NIR blocking filter.

[0024] Near-infrared (NIR) in the context of the present invention preferably refers to a wavelength range of 650 to 1200 nm. UV in the context of the present invention preferably refers to a wavelength range of less than 400 nm, more preferably less than 420 nm. In principle, it is conceivable to use a component coated with an interference filter as a component blocking a specific wavelength range. However, such interference filters utilize reflection to block unwanted radiation, which can lead to ghosting, particularly due to the reflections. Therefore, for high-quality digital color cameras, the use of absorption filters with NIR or UV blocking properties is advantageous, as this reduces the risk of ghosting and stray light.

[0025] Preferably, the length of the beam path through the optical component comprising at least one absorption filter larger than 0.5 mm, more preferably larger than 0.6 mm, more preferably larger than 0.7 mm, and particularly preferably larger than 0.8 mm. In embodiments in which the first and / or second prism comprises at least one absorption filter, the beam path through the component is, in preferred embodiments, further larger than 1.3 mm, more preferably larger than 1.5 mm, more preferably larger than 1.8 mm, more preferably larger than 2.0 mm, and also more preferably larger than 3.0 mm or larger than 4.0 mm.

[0026] Preferably, the first and / or the second prism has a leg length greater than 1.0 to 10 mm, preferably greater than 1.3 to 7 mm, preferably greater than 1.5 to 6 mm, preferably greater than 1.8 to 5 mm.

[0027] Preferably, the first and / or the second planar element has a thickness greater than 0.5 to 2.5 mm, preferably greater than 0.6 to 2.0 mm, preferably greater than 0.8 to 1.5 mm, preferably greater than 0.5 to 1.0 mm.

[0028] In the optical system according to the invention, the at least one NIR blocking filter is preferably an NIR-absorbing filter glass, particularly preferably at least one glass doped with Cu ions, hereinafter also called blue glass, which preferably has a refractive index n d has a refractive index of at least 1.50. dis known to those skilled in the art and refers in particular to the refractive index at a wavelength of approximately 587.6 nm (wavelength of the d-line of helium). In a preferred embodiment, the Cu-ion-doped glasses according to the invention are CuO-containing phosphate glasses, wherein the CuO content is preferably in the range of 1 to 15 wt.%, particularly preferably in the range of 2 to 10 wt.%, and more preferably in the range of 2.5 to 5 wt.%, or CuO-containing fluorophosphate glasses, wherein the CuO content is preferably in the range of 0.1 to 10 wt.%, and particularly preferably in the range of 0.3 to 6.5 wt.%. Such CuO-containing glasses are described, for example, in US 2018 / 0312424 A1, US 2012 / 0165178 A1, US 2006 / 0111231 A1, US 2016 / 0363703 A1 and US 2007 / 0099787 A1.

[0029] In another preferred embodiment, the NIR-absorbing filter glass is a high-refractive-index glass doped with Cu ions and having a refractive index nd of at least 1.70, preferably a CuO-containing glass with a lanthanum-borate glass matrix. Such glasses are described, for example, in WO 2020 / 006770 A1.

[0030] UV blocking filters are optical components which exhibit significantly lower transmission for a first wavelength range of up to 400 nm, preferably up to 420 nm, than for a second wavelength range of 400 nm or preferably 420 to 650 nm. In a preferred embodiment of the invention, the at least one UV blocking filter is a UV-absorbing glass.

[0031] UV blocking filters are preferably made of glass with a steep UV cutoff in the 400 nm range. Suitable glass types include, for example, Schott GG395, GG400, GG420, and GG435.

[0032] In some advantageous embodiments, the use of a component designed as a UV blocking filter according to the invention in the optical arrangement can be omitted. This applies, for example, if the optical component already includes an NIR blocking filter, for example a CuO-containing glass, and provides sufficient blocking in the UV range, or if at least one of the optical components (a) to (e) has a UV-blocking or UV-reflecting coating, in particular an interference coating. The respective absorption filters, preferably the NIR- and UV-absorbing glasses, can be selected according to their mechanical and, in particular, optical properties at their respective positions in the optical arrangement according to the invention. For example, it may be advantageous to select a glass for the first prism, which is located in a comparatively exposed position, that is characterized by high mechanical and / or chemical resistance. It may also be advantageous, especially for the first prism, to select a blue glass with the highest possible refractive index or a UV-absorbing glass. In embodiments in which the first and / or second planar optical element is designed as an NIR blocking filter, the use of comparatively high-refractive-index glasses is not necessary. Here, for example, CuO-containing phosphate or fluorophosphate glasses such as the blue glasses BG40 or BG64 from Schott are suitable.

[0033] The optical components (a), (b), (c), (d), and (e) can furthermore be at least partially coated with at least one optical layer. It is understood that this refers to a coating of the surfaces of the respective optical components. A partial coating within the meaning of the invention represents both a coating of only one of several different surfaces of an optical component and the partial coating of one or more specific surfaces of an optical component.

[0034] Suitable optical layers include, for example, interference filter layer systems, antireflective layer systems, reflective layer systems (such as metallic coatings like aluminum or silver layers), and layer systems that can improve the mechanical and / or chemical resistance of the respective component. It is also conceivable to apply layer systems that represent a combination of the aforementioned layer systems, for example, an interference filter layer that increases mechanical or chemical resistance and / or has an antireflective effect. Such layers are generally known to those skilled in the art.

[0035] As already explained above, the respective optical components of the optical arrangement according to the invention have several surfaces. In a preferred embodiment, at least all optically relevant surfaces of a component are provided with at least a partial, preferably a complete, optical coating. For the purposes of the present invention, an optically relevant surface of a component is understood to be any surface that lies in the path of the light rays, which includes the surface on the incident side, the surface on the emitting side, and also surfaces that reflect or deflect the incident light rays. The various optically relevant surfaces can, of course, be provided with different optical coatings if expedient.

[0036] In a preferred embodiment, at least component (a) and optionally component (e) comprise at least one absorption filter. That is, the first prism and, in some embodiments, the optionally second prism contain at least one absorption filter. In embodiments comprising only a first prism, the first prism naturally comprises at least one absorption filter, preferably an NIR blocking filter. In embodiments comprising both the first and second prisms, both prisms may also comprise at least one absorption filter. However, it is preferred that the first and second prisms comprise different absorption filters, for example, the first prism a NIR blocking filter and the second prism a UV blocking filter.

[0037] In another preferred embodiment, at least one of the components (b) and (d) comprises at least one absorption filter. That is, at least the first planar optical element or the second planar optical element contains at least one absorption filter, preferably an NIR blocking filter. In embodiments comprising only a first or a second planar optical element, only the planar optical element comprises at least one absorption filter. In embodiments comprising both the first and the second planar optical elements, both planar optical elements may also comprise at least one absorption filter. However, it is preferred that the first and the second planar optical elements comprise different absorption filters, for example, the first planar optical element a NIR blocking filter and the second planar optical element a UV blocking filter.

[0038] In a particularly preferred embodiment, the optical arrangement according to the invention comprises a first prism, an optical lens system, and optionally a second prism. More preferably, it consists of the optical components first prism, optical lens system, and optionally a second prism. In other words, the optical arrangement according to the first embodiment comprises only a first prism, a lens system, and optionally a second prism, which are arranged in front of the sensor. In this embodiment, the first prism, and in some embodiments also the second prism (if included), comprises at least one absorption filter, preferably an NIR blocking filter and / or a UV blocking filter, and more preferably an NIR blocking filter.In addition to the aforementioned advantages of a longer beam path through optical components comprising at least one absorption filter, this embodiment also offers the advantage of requiring one less optical component compared to conventional (periscope) camera modules. This is because the deflecting prism and absorption filter component can be integrated into a single optical component. This allows for an even more compact design of the camera module and, moreover, reduces manufacturing costs.

[0039] In a second preferred embodiment, the optical arrangement comprises a first prism, a first planar optical element and / or a second planar optical element, preferably a first or a second planar optical element, particularly preferably a first planar optical element, an optical lens system and optionally a second prism. In this embodiment, the first and / or the second planar optical element preferably comprises at least one absorption filter, preferably an NIR blocking filter and / or a UV blocking filter, particularly preferably an NIR blocking filter.

[0040] Preferably, the optical arrangement of this embodiment comprises a first prism, a first planar optical element comprising at least one absorption filter, preferably a NIR blocking filter, an optical lens system, and optionally a second prism. In one embodiment, the first prism, and in some embodiments also the second prism (if included), comprises at least one absorption filter, preferably a UV blocking filter; however, in a preferred embodiment, the second prism does not include an absorption filter. Also preferably, the optical arrangement of this embodiment comprises a first prism, a first planar optical element comprising at least one absorption filter, preferably a UV blocking filter, an optical lens system, and optionally a second prism.

[0041] In a third preferred embodiment, at least one of the optical components (a), (b), (d) and (e) in the optical arrangement according to the invention represents a composite of at least two, for example also three or four, composite components, wherein at least one of the composite components comprises at least one absorption filter. The individual composite components can be joined together by blasting or by an optical cement or an optically clear adhesive.

[0042] In one embodiment, the first and / or the second prism, preferably the first prism, is designed as such a composite, hereinafter referred to as a "composite prism". Here, for example, a prism-shaped composite component is connected to one or more than one, for example, two or three, planar composite components, hereinafter referred to as the "first", "second", or "third planar composite component".

[0043] At least one of the composite components comprises at least one absorption filter. In a preferred embodiment, all composite components comprise at least one absorption filter. In another preferred embodiment, the composite further comprises at least one composite component which does not comprise an absorption filter as defined in the present invention, for example, a high-refractive-index glass, in particular a glass with a refractive index of n. d from 1.6 to 2.2. A composite obtained in this way is further referred to as a "first prism" or "second prism" within the meaning of the present invention.

[0044] In one embodiment of the optical arrangement, the first and / or the second planar optical element can additionally or alternatively be configured as a composite. Such a composite is further referred to as the "first planar optical element" or "second planar optical element," respectively. Advantageously, this is a composite of two components comprising different absorption filters, for example, a composite of a first planar component comprising a UV blocking filter and a second planar component comprising an NIR blocking filter.

[0045] Of course, such composites can also have one or more optical coatings as described above.

[0046] The optical lens system in the optical arrangement according to the invention can be a single optical lens or, preferably, an arrangement comprising two or more optical lenses. By combining different individual lenses in the optical lens system, chromatic aberrations and distortions in the image can be avoided. Details of exemplary configurations of the optical lens system are known to those skilled in the art and can be found, inter alia, in the prior art mentioned above. List of reference symbols 1 camera module 2 first prism 2b first composite prism 3. First planar optical element 4 optical lens system 5 second plane optical element 6 second prism 6b second composite prism 7 Sensor 8 protective windows 9 Beam path 10 prismatic composite components 11 first planar composite component 12 second plane composite component

[0047] The Fig. Figures 1 to 3 show different embodiments of the optical system according to the invention.

[0048] The Fig. Figures 4a to 4g show different embodiments of a first or second prism designed as a composite according to the invention.

[0049] Fig. Figure 1 depicts a preferred embodiment of the optical system according to the invention. The beam path 9 is designated in the Fig. Figures 1 to 3 merely schematically depict the path of the light (main beam) along the optical axis. It is understood that this does not represent the beam path of a specific half-field angle or wavelength. The diagram shows the path of the incident light through the protective window 8 into the optical arrangement of the camera module 1, first to a first prism 2, which deflects the beam path 9 of the light by 90°. In this embodiment, the first prism 2 is designed as an absorption filter, preferably a blue glass, which acts as a NIR filter. Accordingly, at least a portion of the NIR radiation contained in the incident light is absorbed as it passes through the first prism 2.As described, the light is deflected by 90° by the first prism 2, so that it then passes through the optical lens system 4, which is shown here only by way of example with three lenses, and is deflected by a further 90° by the second prism 6, causing the light to fall onto the sensor 7. The second prism 6 can also include an absorption filter, for example, a NIR filter or a UV blocking filter. If the second prism 6 includes an absorption filter, it is preferably a UV blocking filter. In particularly preferred embodiments, however, the second prism 6 does not include any absorption filters. Both the first prism 2 and the second prism 6, as well as one or more individual lenses of the optical lens system 4, preferably include optical coatings (not shown).These optical coatings are particularly preferentially located on all optically relevant surfaces of the coated optical components.

[0050] Fig. Figure 2 represents a second embodiment of the camera module 1 according to the invention. Unless otherwise described, the individual components and reference drawings are those related to [reference to the original text]. Fig. The explanations mentioned in point 1. Fig. The camera module 1 shown in 2, unlike the one in the Fig. The module described in section 1 has only a first prism 2, but no second prism 6; the light is thus deflected by only 90° and, after passing through the optical lens system 4, hits the sensor 7 directly. This optical arrangement is even more compact due to the absence of a second prism 2.

[0051] Fig. Figure 3 represents a third embodiment of the camera module 1 according to the invention. Unless otherwise described, the individual components and reference drawings are those related to [reference to previous figure]. Fig. 1 and Fig. As explained in section 2, the optical arrangement shown comprises a first prism 2 and a first planar optical element 3, as well as a lens system 4 followed by a second prism 6 and the image sensor 7. Alternatively, in a preferred embodiment, the second prism 6 can be omitted. Accordingly, in this alternative embodiment, the light, after passing through the optical lens system 4, strikes the sensor 7 located behind it without further deflection. This embodiment is particularly advantageous due to its even more compact design. In both the illustrated and the aforementioned alternative embodiment, the first planar optical component comprises an absorption filter, in particular a NIR blocking filter.

[0052] The prism 2 includes an absorption filter and the prism 6 may - if present - also include an absorption filter in some embodiments, but preferably this is not the case.

[0053] The Fig. Figures 4a to 4g show various exemplary embodiments of first and second prisms configured as a composite, referred to below as first composite prism 2a and second composite prism 6a, respectively. First and second composite prisms 2a and 6a each consist of a prismatic composite component 10 and at least one first planar composite component 11 and / or at least one second planar composite component 12. L denotes the light incident on prism 2a or 6a. Preferably, the prismatic composite component 10, the first planar composite component 11, and the second planar composite component 12 are different from one another. By way of example, the composite component 10 can comprise a UV blocking filter, the first planar component 11 a high-refractive-index glass that does not include an absorption filter, and the second planar component 12 a NIR blocking filter.

[0054] Fig. Figure 4a shows a composite prism 2a, 6a comprising a prism-shaped composite component 10 and a first planar composite component 11 applied to its hypotenuse. In a preferred embodiment, a NIR blocking filter is used as the prism-shaped composite component 10, which is connected to a planar composite component 11 made of a high-refractive-index glass, for example with a refractive index n. d of at least 1.6. In a further preferred embodiment, the prism-shaped composite component 10 comprises a UV blocking filter and the applied first planar composite component 11 comprises a high-refractive-index glass.

[0055] Fig. Figure 4b depicts a composite prism 2a, 6a comprising a prism-shaped composite component 10, a first planar composite component 11 applied to its hypotenuse, and a first planar composite component 12 applied to the surface facing the incident light, hereinafter referred to as leg 1. In an advantageous embodiment, the prism-shaped composite component 10 comprises a NIR blocking filter, the first planar composite component 11 a high-refractive-index glass, and the second planar composite component 12 a UV blocking filter. In another advantageous embodiment, the prism-shaped composite component 10 comprises a UV blocking filter, the first planar composite component 11 a high-refractive-index glass, and the second planar composite component 12 a NIR blocking filter.

[0056] Fig. 4c forms a composite prism 2a, 6a, which extends from the one in Fig. Figure 4b differs in that the second planar composite component 12 is applied to the other leg, hereinafter referred to as leg 2. The preferred embodiments for the composite components 10, 11 and 12 correspond to those in connection with Fig. 4 b mentioned.

[0057] Fig. Figure 4d shows another embodiment of a composite prism 2a, 6a, which has the basic structure of the one described in Fig. The composite prism shown in Figure 4b is similar. However, in the present case, a second planar composite component 12 is applied to both leg 1 and leg 2. The preferred embodiments for the composite components 10, 11, and 12 correspond to those in connection with Fig. 4 b and Fig. mentioned in section 4c.

[0058] In Fig. Figure 4e shows a composite prism 2a, 6a which, in addition to a prism-shaped composite component 10, comprises a second planar composite component which is applied to leg 1. The preferred embodiments for the composite components 10 and 12 correspond to those in connection with Fig. 4 b and Fig. mentioned in section 4c.

[0059] In Fig. Figure 4f shows another compound prism 2a, 6a, which differs from the one in Fig. Figure 4e differs in that a second planar composite component 12 is also applied to leg 2. The preferred embodiments for the composite components 10 and 12 correspond to those in connection with Fig. 4 b and Fig. mentioned in section 4c.

[0060] In Fig. 4g is another composite prism 2b, 6b shown, which differs from the one in Fig. Figure 4f differs in that a second planar composite component 12 is applied only to leg 2. The preferred embodiments for the composite components 10 and 12 correspond to those in connection with Fig. 4 b and Fig. 4c mentioned. This embodiment is particularly advantageous with regard to the space requirements in camera modules, since a second planar composite component 12 on leg 1 is dispensed with.

Claims

[1] An optical system for a camera module (1) comprising an image sensor (7) and an optical arrangement defining a beam path (9), wherein in the beam path (9) the optical components contained therein are arranged in the following order in front of the image sensor (7): (a) a first prism (2), (b) optionally a first planar optical element (3), (c) an optical lens system (4), and (e) optionally a second prism (6), wherein at least component (a) comprises at least one absorption filter. [2] Optical system according to claim 1, wherein the at least one absorption filter comprises an NIR blocking filter and / or a UV blocking filter. [3] Optical system according to claim 2, wherein the at least one NIR blocking filter comprises an NIR-absorbing filter glass, particularly preferably at least one blue glass. [4] Optical system according to claim 3, wherein the at least one blue glass has a refractive index of at least 1.

50. [5] Optical system according to claim 2, wherein the UV blocking filter comprises a UV-absorbing glass. [6] Optical system according to any one of claims 1 to 5, wherein at least one of the optical components (a) to (e) is at least partially coated with at least one optical layer. [7] Optical system according to any one of claims 1 to 6, wherein the system comprises the components (a), (c) and optionally (e), preferably consists thereof, and the incident optical beam penetrates the optical components (a), (c) and optionally (e) on its way to the image sensor (7). [8] Optical system according to any one of claims 1 to 7, wherein component (b) comprises at least one absorption filter, preferably an NIR blocking filter. [9] Optical system according to any one of claims 1 to 8, wherein at least one of the optical components (a), (b) and (e), preferably (a) and / or (e), is a composite of at least two composite components, wherein at least one of the composite components comprises at least one absorption filter. [10] Periscope camera module comprising the optical system according to any one of claims 1 to 9.

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