Imaging device with telephoto lens module for electronic device

Abstract

An optical imaging device, specifically a camera, with a telephoto lens module for imaging objects is disclosed. The imaging device (100) includes an optical path length extension element (120) with a polarizing beam splitter (PBS) (121), the PBS (121) being used to split an incident beam along a first sub-optical axis into a first beam and an incident beam along a perpendicular second sub-optical axis into a second beam. The optical path length extension element (120) further includes: a first wave delayer (122a) and a first reflector (123a), arranged along the first sub-optical axis, for phase delaying the first beam and reflecting the first beam back along the first sub-optical axis; a second wave delayer (122b) and a second reflector (123b), arranged along the second sub-optical axis, for phase delaying the second beam and reflecting the second beam back along the second sub-optical axis. The PBS (121) is also used to recombine the first beam and the second beam into an outgoing beam along the principal optical axis. The imaging device (100) further includes: a lens assembly (130) for forming an image of the object in the imaging plane of the imaging device (100) according to the outgoing light beam, or for forming the incident light beam; and an imaging sensor (140) for capturing the image of the object in the imaging plane.

Description

Technical Field

[0001] This invention generally relates to optical imaging devices. More specifically, this invention relates to an optical imaging device with a telephoto lens module for electronic devices such as smartphones and tablets, specifically a camera. Background Technology

[0002] Smartphones have become an indispensable part of our daily lives, and the camera function is one of the most popular features. With technological advancements, smartphone manufacturers are constantly striving to enhance camera capabilities to improve image quality and offer additional functionalities. Common camera modules in today's popular smartphones include main wide-angle, ultra-wide-angle, and telephoto lenses.

[0003] Telephoto camera modules have a longer focal length than main camera modules, enabling a narrower field of view and greater optical zoom, allowing users to magnify distant objects with good image quality. Focal length determines the magnification and optical zoom level a camera can achieve. Longer focal lengths allow for higher levels of zoom. However, a common technical challenge associated with smartphone telephoto camera modules is the physical size and space constraints related to the long focal length system required to build telephoto functionality. Smartphone manufacturers must find ways to accommodate large focal length lenses and optical systems within a miniaturized smartphone form factor without increasing the overall thickness of the device.

[0004] To address the space constraints of telephoto camera modules in smartphones, the periscope design represents the pinnacle of technology. A periscope design is a folded optical device that typically uses prisms or mirrors to reflect light from the camera module, effectively increasing its optical path length. These prisms or mirrors are positioned at specific angles to achieve the desired optical folding. This results in a total track length (TTL) of the lens system that is significantly smaller than the actual focal length, enabling optical zoom without increasing the size of the camera module—ideal for slim smartphones. Another advantage of this folded optical device design is in image stabilization, as the relatively short physical length of the camera module reduces the impact of camera shake, thus improving image stability during handheld shooting.

[0005] While the folded optics design of traditional periscopes increases the optical path length, this may not be sufficient to provide adequate optical zoom within a compact form factor. For example, in some traditional smartphone periscope designs, two prisms are used to fully fold the optical path before it reaches the sensor. This increases the cost and weight of the camera module. Using two prisms reduces the space within the module required for the lens elements to move to achieve zoom functionality. Summary of the Invention

[0006] One object of the present invention is to provide an optical imaging device with a telephoto lens module for electronic devices such as smartphones and tablets, specifically a camera, wherein the telephoto lens module has an increased optical path length.

[0007] The above and other objectives are achieved through the subject matter claimed in the independent claims. Other implementations are apparent in the dependent claims, the specification, and the drawings.

[0008] According to a first aspect, a telephoto imaging device for imaging an object is provided, specifically a camera. The imaging device includes: an optical path length extending element, wherein the optical path length extending element includes: a polarizing beam splitter (PBS), used to split an incident beam along a first sub-optical axis into a first beam with a first polarization, and to split an incident beam along a perpendicular second sub-optical axis into a second beam with a second polarization, the second polarization being orthogonal to the first polarization. Furthermore, the optical path length extending element also includes: a first wave delayer and a first reflector, arranged along the first sub-optical axis, used to phase delay the first beam and reflect the first beam back along the first sub-optical axis; a second wave delayer and a second reflector, arranged along the second sub-optical axis, used to phase delay the second beam and reflect the second beam back along the second sub-optical axis. The PBS is also used to recombine the first beam phase-delayed and reflected by the first wave delayer and the first reflector, and the second beam phase-delayed and reflected by the second wave delayer and the second reflector, into an outgoing beam along the principal optical axis of the imaging device. Furthermore, the imaging device includes: a lens assembly for forming an image of the object in the imaging plane of the imaging device based on the outgoing light beam, or for forming the incident light beam for forming an image of the object in the imaging plane of the imaging device. The imaging device also includes: an imaging sensor, such as a light sensor, for capturing the image of the object in the imaging plane.

[0009] Therefore, the imaging apparatus according to the first aspect and the various implementations and embodiments described below facilitates further reduction of the TTL of the imaging optics using at least one optical path length extending element with a PBS that splits the incident beam into mutually orthogonal polarizations and then passes it through, for example, a 90° phase difference sensing waveplate, thereby increasing the effective optical path length of the beam by at least one arm length of the optical path length extending element. The imaging apparatus according to the first aspect facilitates the use of previously unused space in the camera module, wherein the optical elements increase the optical path length of the incident light before reaching the imaging sensor. Therefore, the imaging apparatus according to the first aspect provides more free space in the imaging optics to aid the optical zoom function of the camera module, thereby maintaining image quality.

[0010] In another possible implementation, the imaging device further includes a lens barrel, wherein the lens barrel houses the lens assembly and is movable along the principal optical axis relative to the optical path length extension element and / or the imaging sensor.

[0011] In another possible implementation, the imaging apparatus includes one or more additional optical path length extending elements disposed between the lens assembly and the imaging sensor. Each additional optical path length extending element may include additional photodiodes (PBSs) for splitting an incident beam along an additional first secondary optical axis into additional first beams with a first polarization, and splitting an incident beam along a perpendicular additional second secondary optical axis into additional second beams with a second orthogonal polarization. Furthermore, each optical path length extending element may also include: additional first wave delayers and additional first reflection elements, disposed along the first secondary optical axis, for phase delaying the additional first beams and reflecting the additional first beams back along the additional first secondary optical axis; and additional second wave delayers and additional second reflection elements, disposed along the additional second secondary optical axis, for phase delaying the additional second beams and reflecting the additional second beams back along the additional second secondary optical axis. The other PBS of each other optical path length extension element is also used to recombine the other first beams phase-delayed and reflected by the other first wave delayers and the other first reflective elements, and the other second beams phase-delayed and reflected by the other second wave delayers and the other second reflective elements, into an outgoing beam along the principal optical axis.

[0012] In another possible implementation, the imaging device includes three additional optical path length extension elements and a mirror assembly, wherein the optical path length extension elements, the three additional optical path length extension elements, and the mirror assembly are arranged in a roof-type configuration.

[0013] In another possible implementation, the optical path length extending element may include two orthogonally arranged photodiodes (PBSs). More specifically, in another possible implementation, the optical path length extending element may further include other PBSs for splitting the incident beam along another first secondary optical axis into another first beam with a first polarization, and splitting the incident beam along a perpendicular second secondary optical axis into another second beam with a second orthogonal polarization. Furthermore, the optical path length extending element includes: other first wave delayers and other first reflection elements, arranged along the first secondary optical axis, for phase delaying the other first beams and reflecting them back along the other first secondary optical axis; and other second wave delayers and other second reflection elements, arranged along the other second secondary optical axis, for phase delaying the other second beams and reflecting them back along the second secondary optical axis. The other PBS is also used to recombine the other first beams, which are phase-delayed and reflected by the other first wave delayers and the other first reflective elements, and the other second beams, which are phase-delayed and reflected by the other second wave delayers and the other second reflective elements, into other outgoing beams along the principal optical axis. The first and second sub-optical axes of the PBS define a plane perpendicular to another plane defined by the other first and second sub-optical axes of the other PBS.

[0014] In another possible implementation, the lens assembly is used to form the image of the object in the imaging plane of the imaging device based on the outgoing beam formed by the PBS and the other outgoing beams formed by the other PBS.

[0015] In another possible implementation, the first and / or second reflective elements of the optical path length extension element comprise a mirror or a retroreflector. In one implementation, the mirror may be a plane mirror or a curved mirror.

[0016] In another possible implementation, the imaging device includes other lens assemblies arranged in front of the object side of the optical path length extension element.

[0017] In another possible implementation, the other lens components include at least one convex lens surface.

[0018] In another possible implementation, the PBS comprises one or more planar layers arranged at an angle of approximately 45° relative to the first sub-optical axis and / or the second sub-optical axis.

[0019] In another possible implementation, the first wave delayer and / or the second wave delayer are used to generate a 90° phase shift.

[0020] In another possible implementation, the first wave delayer and / or the second wave delayer include a quarter wave plate (QWP).

[0021] In another possible implementation, the imaging device further includes a prism, specifically a 45° prism, which is arranged along the main optical axis between the lens assembly and the imaging sensor or in front of the optical path length extension element.

[0022] In another possible implementation, the ratio of the distance between the image side of the optical path extension element and the object side of the lens assembly closest to the imaging sensor to the effective focal length (EFL) is less than 0.6.

[0023] In a second aspect, an electronic device, specifically a smartphone or tablet computer, is provided, the electronic device including a telephoto imaging device according to any one of the preceding claims.

[0024] Details of one or more embodiments are set forth in the accompanying drawings and description. Other features, objectives, and advantages will be apparent from the description, drawings, and claims. Attached Figure Description

[0025] The embodiments of the present invention will be described in detail below with reference to the following figures, wherein:

[0026] Figure 1a A diagram of an imaging apparatus provided in one embodiment, the imaging apparatus including an optical path length extension element having a PBS;

[0027] Figure 1b for Figure 1a A diagram showing more details of the optical path length extension element of the imaging device;

[0028] Figure 1c A diagram of an imaging apparatus provided for another embodiment, the imaging apparatus comprising two optical path length extension elements having corresponding PBS;

[0029] Figure 2a , Figure 2b Figures for two other embodiments of an imaging apparatus including lens assemblies for two magnifications;

[0030] Figure 2c For specifying the use of Figure 2a , Figure 2b A table of lens parameters for the embodiments shown;

[0031] Figure 3a , Figure 3bFigures for two other embodiments of an imaging apparatus including lens assemblies for two magnifications;

[0032] Figure 3c For specifying the use of Figure 3a , Figure 3b A table of lens parameters for the embodiments shown;

[0033] Figure 4a , Figure 4b The figures show two other embodiments of the imaging device, which includes lens assemblies for two magnifications and a prism disposed between the lens assemblies and the imaging sensor.

[0034] Figure 4c For specifying the use of Figure 4a , Figure 4b A table of lens parameters for the embodiments shown;

[0035] Figure 5a , Figure 5b The figures show two other embodiments of the imaging device, which includes lens assemblies for two magnifications and a planar parallel material plate disposed between the lens assemblies and the imaging sensor.

[0036] Figure 5c For specifying the use of Figure 5a , Figure 5b A table of lens parameters for the embodiments shown;

[0037] Figure 6a , Figure 6b The figures show two other embodiments of the imaging device, which includes a lens assembly for two magnifications and a prism disposed in front of the lens assembly and an optical path length extension element having a PBS disposed between the lens assembly and the imaging sensor.

[0038] Figure 6c For specifying the use of Figure 6a , Figure 6b A table of lens parameters for the embodiments shown;

[0039] Figure 7a , Figure 7b The figures show two other embodiments of the imaging device, which includes a lens assembly for two magnifications and a prism disposed in front of the lens assembly and an optical path length extension element having a PBS disposed between the lens assembly and the imaging sensor.

[0040] Figure 7c For specifying the use of Figure 7a , Figure 7b A table of lens parameters for the embodiments shown;

[0041] Figure 8a , Figure 8b The figures show two other embodiments of the imaging apparatus, which include lens assemblies for two magnifications and other optical path length extension elements having a PBS disposed between the lens assembly and the imaging sensor.

[0042] Figure 8c For specifying the use of Figure 8a , Figure 8b A table of lens parameters for the embodiments shown;

[0043] Figure 9a , Figure 9b The figures show two other embodiments of the imaging apparatus, which include lens assemblies for two magnifications and other optical path length extension elements having a PBS disposed between the lens assembly and the imaging sensor.

[0044] Figure 9c For specifying the use of Figure 9a , Figure 9b A table of lens parameters for the embodiments shown;

[0045] Figure 10 The figure shows another embodiment of the imaging device, which includes four optical path length extension elements in a roof-type arrangement;

[0046] Figure 11 A diagram of another embodiment of the imaging device;

[0047] Figures 12a to 12c The figure shows another embodiment of an imaging device having an optical path length extension element, which includes a first PBS and a vertically arranged second PBS.

[0048] In the following text, the same reference numerals refer to the same or at least functionally equivalent features. Detailed Implementation

[0049] In the following description, reference is made to the accompanying drawings, which form part of this invention, and which illustrate specific aspects of embodiments of the invention or aspects in which embodiments of the invention may be used. It should be understood that embodiments of the invention can be used in other aspects and include structural or logical variations not described in the drawings. Therefore, the detailed description below is not intended to be limiting, and the scope of the invention is defined by the appended claims.

[0050] For example, it should be understood that disclosures relating to a described method may also apply to a corresponding device or system for performing the method, and vice versa. For instance, if one or more specific method steps are described, the corresponding device may include one or more units, such as functional units, for performing the described one or more method steps (e.g., a unit performing the one or more steps, or multiple units each performing one or more of the plurality of steps), even if such units are not explicitly described or illustrated in the figures. On the other hand, for example, if a particular apparatus is described according to one or more units (e.g., functional units), the corresponding method may include a step to perform the function of one or more units (e.g., a step performing the function of the one or more units, or multiple steps each performing the function of one or more of the plurality of units), even if such steps are not explicitly described or illustrated in the figures. Furthermore, it should be understood that, unless specifically indicated otherwise, features of the various exemplary embodiments and / or aspects described herein may be combined with each other.

[0051] Before describing the detailed embodiments below, some technical background and terminology will be introduced using one or more of the following abbreviations:

[0052] Total Track Length of TTL Lenses

[0053] PBS Polarizing Beam Splitter

[0054] Quarter Wave Plate (QWP)

[0055] Left Circularly Polarized (LCP)

[0056] RCP Right Circularly Polarized

[0057] Polarization of light: the direction of electric field vector oscillation

[0058] s-polarized light: Light whose electric field vector oscillates perpendicular to the plane of incidence. This polarization is also called transverse electric (TE) polarization.

[0059] p-polarized light: Light whose electric field vector oscillates parallel to the plane of incidence. This polarization is also called transverse magnetic (TM) polarization.

[0060] Circularly polarized light: Light whose individual components oscillate with a relative phase difference of 90°.

[0061] Foldable optics: An optical system in which a light beam is bent in such a way that the optical path is much larger than the size of the system.

[0062] Figure 1a Figure 100 illustrates an imaging device 100 provided in one embodiment. In one embodiment, the imaging device 100 is provided in the form of a telephoto camera 100 for use in electronic devices such as smartphones and tablets. As will be described in more detail below and as shown in Figure 1b As shown in more detail, the imaging apparatus 100 includes an optical path length extension element 120 with a polarizing beamsplitter (PBS) 121. The PBS 121 is used to split an incident light beam from an object to be imaged along a first secondary optical axis of the imaging apparatus 100 into a first beam having a first polarization (e.g., s-polarization), and to split an incident light beam along a second secondary optical axis perpendicular to the imaging apparatus 100 into a second beam having a second polarization (e.g., p-polarization), the second polarization being orthogonal to the first polarization. Therefore, as will be understood, the embodiments disclosed herein utilize the fact that natural light is generally unpolarized by nature and can be assumed to be a superposition of s-polarization and p-polarization. In one embodiment, when light from the object to be imaged illuminates the PBS 121, the PBS 121 may be several layers of dielectric coating oriented at 45° relative to the incident light beam, splitting the incident light into two directions, each having either s-polarization or p-polarization, such as... Figure 1b As shown. In one embodiment, Figure 1a , Figure 1b The PBS 121 of the imaging device 100 shown can be used, for example, to reflect s-polarization and transmit p-polarization.

[0063] like Figure 1a , Figure 1b As shown, the optical path length extension element 120 further includes: a first wave delayer 122a and a first reflective element 123a, arranged along the first secondary optical axis, for phase delaying the first beam and reflecting the first beam back along the first secondary optical axis; a second wave delayer 122b and a second reflective element 123a, arranged along the second secondary optical axis, for phase delaying the second beam and reflecting the second beam back along the second secondary optical axis. Figure 1a , Figure 1bIn the illustrated embodiment, the first and second wave delayers 122a can be implemented as quarter-wave plates (QWPs) 122a, 122b and / or the first reflective element 123a and the second reflective element 123b can be implemented as mirrors or retroreflectors 123a, 123b. Retroreflectors 123a, 123b can be implemented as a microarray of cube retroreflectors. Using reflective elements 123a, 123b in the form of retroreflectors 123a, 123b ensures that the resulting s-polarized and p-polarized beams propagating to the subsequent lens assembly 130 and optical sensor 140 remain parallel to each other with precision, as will be described in more detail below. Such an embodiment simplifies the manufacturing tolerances of the optical path length extension element 120.

[0064] The PBS 121 is further configured to recombine the first beam, which is phase-delayed and reflected by the first wave delayer 122a and the first reflective element 123a, and the second beam, which is phase-delayed and reflected by the second wave delayer 122b and the second reflective element 123b, into an outgoing beam arrangement along the principal optical axis of the imaging device 100. As described above, the imaging device 100 may further include: a lens assembly 130 for forming an image of the object in the imaging plane of the imaging device 100 based on the outgoing beam; and an imaging sensor 140, such as a light sensor 140, for capturing the image of the object in the imaging plane.

[0065] Therefore, as will be understood, in Figure 1b In the illustrated embodiment, each separated beam transmitted / reflected by the PBS 121 encounters quarter-wave plates 122a, 122b (e.g., a first QWP 122a for s-polarization and a second QWP 122b for p-polarization) polarized at 45° relative to the incident light, making each of them circularly polarized (e.g., LCP for reflected light). This LCP light then continues to strike a first reflector 123a, which then flips its polarization by 180°, producing RCP light (in this example). This RCP light now propagates again through the same first QWP 122a, which converts the RCP light into p-polarized light. When this p-polarized light strikes the PBS 121 again, it is simply transmitted through and continues to propagate along the principal optical axis of the imaging device 100 toward the lens assembly 130 and the light sensor 140. In exactly the same way, the initial transmission component of the unpolarized incident light (i.e., p-polarized light) becomes s-polarized after interacting with the second QWP 122b and the second mirror 123b, and propagates toward the lens assembly 130 and the light sensor 140.

[0066] Therefore, the imaging device 100 and the different implementations and embodiments described in the context facilitate further reduction of the TTL of the imaging optics using an optical path length extension element 120 with a PBS 121 that separates the incident beam into mutually orthogonal polarizations and then passes it through, for example, 90° phase difference sensing waveplates 122a, 122b, thereby increasing the effective optical path length of the beam by at least one arm length L of the optical path length extension element 120. The imaging device 100 facilitates the use of previously unused space in a camera module with an optical path length extension element 120 that increases the optical path length of the incident light before reaching the imaging sensor 140. Thus, the imaging device 100 provides more free space in the imaging optics to aid the optical zoom function of the camera module while maintaining image quality.

[0067] exist Figure 1a , Figure 1b In the illustrated embodiment, the imaging apparatus 100 includes additional lens assemblies 110 arranged along the main (folded) optical axis in front of the optical path length extender 120 for focusing an incident light beam onto the PBS 121 of the optical path length extender 120. In one embodiment, the additional lens assembly 110 may include at least one convex lens surface. Figure 1a As shown, the imaging device 100 may further include a lens barrel that houses the lens assembly 130 and is movable along the main optical axis of the imaging device 100 relative to the optical path length extension element 120 and / or the imaging sensor 140.

[0068] Figure 1c It shows Figure 1a In another embodiment of the imaging device 100, the imaging device 100 includes additional optical path length extending elements 150 arranged along the main optical axis of the imaging device 100 between the lens assembly 130 and the imaging sensor 140. In one embodiment, the additional optical path length extending elements 150 are the same as or at least similar to the optical path length extending elements 120. In other words, similar to the optical path length extending elements 120, the additional optical path length extending elements 150 include a first wave delay 152a and a second wave delay 152b, as well as a first reflective element 153a and a second reflective element 153b, which have the same function as the corresponding elements 122a, 122b and 123a, 123b of the optical path length extending elements 120. As will be understood, due to the additional 90° deflection caused by the additional optical path length extending elements 150, the main optical axis of the imaging device 100 is folded again (with...). Figure 1a , Figure 1b Compared to the embodiments shown).

[0069] In the following description, further detailed embodiments of the imaging apparatus 100 will be described in the context of the other accompanying drawings. In at least some of these drawings, wave delayers 122a, 122b and reflective elements 123a, 123b of the optical path length extension element 120 have been omitted for clarity when depicting the optical path length extension element 120.

[0070] Figure 2a , Figure 2b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown, while Figure 2c The regulations are shown Figure 2a , Figure 2b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 2a , Figure 2b In the illustrated embodiment, other lens assemblies 110 arranged before the optical path length extender 120 include lenses L1 and L2, and lens assembly 130 arranged between the optical path length extender 120 and the imaging sensor 140 includes lenses L3, L4, L5, L6, and L7 (the parameters of which are as follows: ...). Figure 2c (Specified in the table). In Figure 2a , Figure 2b In the illustrated embodiment, the distance m1 along the principal optical axis and the effective focal length (EFL) between the image side of the optical path length extension element 120 and the image side of the lens L7 satisfies the following requirement: m1 / EFL = 0.50. The effective focal length (EFL) and the maximum half image height (IMH) satisfy the following requirement: EFL / IMH = 3.83 > 3. For Figure 2a , Figure 2b In the embodiment shown, the EFL is 28.37 mm, F# is 1.9, IMH is 7.4 mm, HFOV is 14.36°, and TTL is 27.51 mm. The modulation transfer function (MTF) of this embodiment is greater than 0.2 up to 300 cycles per millimeter spatial frequency.

[0071] Figure 3a , Figure 3b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown (with...). Figure 2a , Figure 2b The embodiments shown are similar, while Figure 3c The regulations are shown Figure 3a , Figure 3b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 3a , Figure 3b In the illustrated embodiment, other lens assemblies 110 arranged before the optical path length extender 120 include lenses L1 and L2, and lens assembly 130 arranged between the optical path length extender 120 and the imaging sensor 140 includes lenses L3, L4, L5, L6, and L7 (the parameters of which are as follows: ...). Figure 3c (Specified in the table). In Figure 3a , Figure 3b In the illustrated embodiment, the distance m1 along the optical axis and the effective focal length (EFL) between the image side of the optical path length extension element 120 and the image side of the lens L7 satisfies the following requirement: m1 / EFL = 0.64. The effective focal length (EFL) and the maximum half image height (IMH) satisfy the following requirement: EFL / IMH = 3.87. For Figure 3a , Figure 3b In the embodiment shown, the EFL is 27.51 mm, F# is 1.97, IMH is 7.1 mm, HFOV is 14.36°, and TTL is 29.82 mm. The MTF of this embodiment is greater than 0.2 up to 150 cycles per millimeter spatial frequency.

[0072] Figure 4a , Figure 4b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown, while Figure 4c The regulations are shown Figure 4a , Figure 4b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 4a , Figure 4b In the illustrated embodiment, the imaging device 100 further includes a prism 160 arranged along the principal optical axis between the lens assembly 130 and the imaging sensor 140. Other lens assemblies 110 arranged before the optical path length extender 120 include lenses L1 and L2, and the lens assembly 130 arranged between the optical path length extender 120 and the prism 160 includes lenses L3, L4, L5, L6, and L7 (the parameters of which are...). Figure 4c (Specified in the table). In Figure 4a , Figure 4b In the illustrated embodiment, the distance m1 along the principal optical axis and the effective focal length (EFL) between the image side of the optical path length extension element 120 and the image side of the lens L7 satisfies the following requirement: m1 / EFL = 0.44. The effective focal length (EFL) and the maximum half image height (IMH) satisfy the following requirement: EFL / IMH = 3.59 > 3. For Figure 4a , Figure 4b In the embodiment shown, the EFL is 23 mm, F# is 1.983, IMH is 6.4 mm, HFOV is 15.5°, and TTL is 24.9 mm. The MTF of this embodiment is greater than 0.2 up to 300 cycles per millimeter spatial frequency.

[0073] Figure 5a , Figure 5b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown, while Figure 5c The regulations are shown Figure 5a , Figure 5b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 5a , Figure 5b In the illustrated embodiment, the imaging device 100 further includes a planar parallel material block 170 arranged along the principal optical axis between the lens assembly 130 and the imaging sensor 140. Other lens assemblies 110 arranged before the optical path length extender 120 include lenses L1 and L2, and the lens assembly 130 arranged between the optical path length extender 120 and the material block 170 includes lenses L3, L4, L5, L6, and L7 (the parameters of which are...). Figure 5c (Specified in the table). In Figure 5a , Figure 5b In the illustrated embodiment, the distance m1 along the principal optical axis and the effective focal length (EFL) between the image side of the optical path length extension element 120 and the image side of the lens L7 satisfies the following requirement: m1 / EFL = 0.34. The effective focal length (EFL) and the maximum half image height (IMH) satisfy the following requirement: EFL / IMH = 3.84 > 3. For Figure 5a , Figure 5b In the embodiment shown, the EFL is 30.4 mm, F# is 1.96, IMH is 7.91 mm, HFOV is 14.36°, and TTL is 25.2 mm. The MTF of this embodiment is greater than 0.2 up to 300 cycles per millimeter spatial frequency.

[0074] Figure 6a , Figure 6b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown, while Figure 6c The regulations are shown Figure 6a , Figure 6b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 6a , Figure 6bIn the illustrated embodiment, the imaging device 100 further includes a prism 160 arranged along the principal optical axis between the lens assembly 130 and other lens assemblies 110. An optical path length extension element 120 is arranged along the principal optical axis between the lens assembly 130 and the imaging sensor 140. The other lens assemblies 110 arranged before the prism 160 include lens L1, and the lens assembly 130 arranged between the prism 160 and the optical path length extension element 120 includes lenses L2, L3, L4, L5, L6, and L7 (the parameters of which are...). Figure 6c (As specified in the table shown). In Figure 6a , Figure 6b In the illustrated embodiment, the distance l1 along the principal optical axis and the effective focal length (EFL) between the image side of the prism 160 and the object side of the optical path length extension element 120 satisfies the following requirement: l1 / EFL = 0.45. The effective focal length (EFL) and the maximum half-image height (IMH) satisfy the following requirement: EFL / IMH = 4.96 > 4. For Figure 6a , Figure 6b In the embodiment shown, the EFL is 28.3 mm, F# is 2.18, IMH is 5.7 mm, HFOV is 11.3°, and TTL is 27 mm. The MTF of this embodiment is greater than 0.2 up to 150 cycles per millimeter spatial frequency.

[0075] Figure 7a , Figure 7b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown (with...). Figure 6a , Figure 6b The embodiments shown are similar, while Figure 7c The regulations are shown Figure 7a , Figure 7b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 7a , Figure 7b In the illustrated embodiment, the imaging device 100 further includes a prism 160 arranged along the principal optical axis between the lens assembly 130 and other lens assemblies 110. An optical path length extension element 120 is arranged along the principal optical axis between the lens assembly 130 and the imaging sensor 140. The other lens assemblies 110 arranged before the prism 160 include lens L1, and the lens assembly 130 arranged between the prism 160 and the optical path length extension element 120 includes lenses L2, L3, L4, L5, L6, and L7 (the parameters of which are...). Figure 7c (As specified in the table shown). In Figure 7a , Figure 7bIn the illustrated embodiment, the distance l1 along the principal optical axis and the effective focal length (EFL) between the image side of the prism 160 and the object side of the optical path length extension element 120 satisfies the following requirement: l1 / EFL = 0.52. The effective focal length (EFL) and the maximum half-image height (IMH) satisfy the following requirement: EFL / IMH = 4.18 > 4. For Figure 7a , Figure 7b In the embodiment shown, the EFL is 23.8 mm, F# is 2, IMH is 5.7 mm, HFOV is 13.3°, and TTL is 26.54 mm. The MTF of this embodiment is greater than 0.2 up to 180 cycles per millimeter spatial frequency.

[0076] Figure 8a , Figure 8b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown (with...). Figure 1c The embodiments shown are similar, while Figure 8c The regulations are shown Figure 8a , Figure 8b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 8a , Figure 8b In the embodiment shown, the imaging device 100 further includes other optical path length extension elements 150 arranged along the principal optical axis between the lens assembly 130 and the imaging sensor 140, as described above. Figure 1c As described in the context. Other lens assemblies 110 arranged before prism 160 include lens L1, and lens assembly 130 arranged between optical path length extender 120 and other optical path length extenders 150 includes lenses L2, L3, L4, L5, L6, and L7 (the parameters of which are described in the context of...). Figure 8c (As specified in the table shown). In Figure 8a , Figure 8b In the illustrated embodiment, the distance l1 along the principal optical axis and the effective focal length (EFL) between the image side of the optical path length extension element 120 and the object side of other optical path length extension elements 150 satisfies the following requirement: l1 / EFL = 0.41. The effective focal length (EFL) and the maximum half-image height (IMH) satisfy the following requirement: EFL / IMH = 4.96 > 4. For Figure 8a , Figure 8bIn the embodiment shown, the EFL is 28.3 mm, F# is 2.18, IMH is 5.7 mm, HFOV is 11.3°, and TTL is 25.9 mm. The MTF of this embodiment is greater than 0.2 up to 200 cycles per millimeter spatial frequency.

[0077] Figure 9a , Figure 9b Two other embodiments of the imaging apparatus 100 for two different magnification values ​​are shown (with...). Figure 8a , Figure 8b The embodiments shown are similar, while Figure 9c The regulations are shown Figure 9a , Figure 9b A table showing the lens parameters of lens assembly 130 and other lens assemblies 110 in the illustrated embodiment. Figure 9a , Figure 9b In the embodiment shown, the imaging device 100 further includes other optical path length extension elements 150 arranged along the principal optical axis between the lens assembly 130 and the imaging sensor 140, as described above. Figure 1c As described in the context. Other lens assemblies 110 arranged before prism 160 include lens L1, and lens assembly 130 arranged between optical path length extender 120 and other optical path length extenders 150 includes lenses L2, L3, L4, L5, L6, and L7 (the parameters of which are described in the context of...). Figure 9c (As specified in the table shown). In Figure 9a , Figure 9b In the illustrated embodiment, the distance l1 along the principal optical axis and the effective focal length (EFL) between the image side of the optical path length extension element 120 and the object side of other optical path length extension elements 150 satisfies the following requirement: l1 / EFL = 0.37. The effective focal length (EFL) and the maximum half-image height (IMH) satisfy the following requirement: EFL / IMH = 5.60 > 4. For Figure 9a , Figure 9b In the embodiment shown, the EFL is 31.9 mm, F# is 2.4, IMH is 5.7 mm, HFOV is 10.0°, and TTL is 25.9 mm. The MTF of this embodiment is greater than 0.2 up to 200 cycles per millimeter spatial frequency.

[0078] Figure 10Another embodiment of the imaging device 100 is shown, which includes four optical path length extending elements 120, 150, 220, 250 in a roof-type arrangement and a mirror structure 180 with two mirror surfaces 180a, 180b, which helps to further increase the optical path length provided by the imaging device 100. In one embodiment, the other optical path length extending elements 150, 220, 250 are the same as or at least similar to optical path length extending element 120. In other words, similar to the optical path length extending element 120, the other optical path length extending elements 150, 220, and 250 may include first wave delayers 152a, 222a, and 252a, and second wave delayers 152b, 222b, and 252b, as well as first reflective elements 153a, 223a, and 253a, and second reflective elements 153b, 223b, and 253b, which have the same function as their counterparts 122a, 122b and 123a, 123b of the optical path length extending element 120. As will be understood, due to the additional 90° deflection caused by the three other optical path length extending elements 150, 220, and 250, the principal optical axis of the imaging device 100 is folded again (with...). Figure 1a , Figure 1b Compared to the embodiments shown).

[0079] Figure 11 Another embodiment of the imaging device 100 is shown. Figure 11 In the illustrated embodiment, the first reflective element 123a and the second reflective element 123b of the optical path length extension element 120 are implemented in the form of curved mirrors 123a and 123b. Figure 11 As shown, in this embodiment, one or more lenses of the lens assembly 130 can be omitted to achieve an even more compact design of the imaging device 100.

[0080] Figures 12a to 12c Another embodiment of the imaging device 100 is shown, wherein the optical path length extension element 120 includes two PBSs, namely a first PBS 121 and a second PBS 127, arranged at an angle relative to the first PBS 121. More specifically, in Figures 12a to 12cIn the illustrated embodiment, the optical path length extension element 120, in addition to the PBS 121, includes a first wave delayer 122a and a second wave delayer 122b, a first reflective element 123a and a second reflective element 123b, and other PBS 126, other first wave delayers 127a and other first reflective elements 128a, and other second wave delayers 127b and other second reflective elements 128b. The other PBS 126 is used to split the incident beam along the other first sub-optical axis into other first beams, and to split the incident beam along the perpendicular other second sub-optical axis into other second beams. The other first wave delayers 127a and other first reflective elements 128a, arranged along the other first sub-optical axis, are used to phase delay the other first beams and reflect the other first beams back along the other first sub-optical axis. Other second-wave delayers 127b and other second-reflecting elements 128b, arranged along the other second secondary optical axis, are used to phase delay the other second beams and reflect them back along the other second secondary optical axis. The other PBS 126 is also used to recombine the other first beams phase-delayed and reflected by the other first-wave delayers 127a and other first-reflecting elements 128a, and the other second beams phase-delayed and reflected by the other second-wave delayers 127b and other second-reflecting elements 128b, into other outgoing beams along the principal optical axis of the imaging device 100. Specifically, as... Figure 12a As shown, the first sub-optical axis and the second sub-optical axis of the PBS 121 define a plane that is perpendicular to other planes defined by the other first sub-optical axis and the other second sub-optical axis of the other PBS 126.

[0081] Therefore, as will be understood, Figures 12a to 12cThe illustrated embodiment can further increase the optical path length to twice the arm length of the optical path length extension element 120. As described above, the optical path length extension element 120 includes two polarization-sensitive planes 121, 126 in the form of two polarization-sensitive planes 121, 126, wherein, for example, one plane (referred to as plane 1) is located in the yz plane that splits the incident light beam into its constituent s-polarized and p-polarized components, for reflecting the s-polarized component incident on said plane and transmitting the p-polarized component. Meanwhile, for example, another plane (referred to as plane 2) is located in the xy plane, for reflecting the p-polarized component incident on said plane and transmitting the s-polarized component. When incident light irradiates the optical path length extension element 120, its s-polarized component is reflected to the (λ / 4 plate 2 + mirror) system, which reflects and converts it into p-polarized light. This p-polarized light strikes plane 2 in the xy plane, is reflected towards the (λ / 4 plate 1 + mirror) system, is reflected and converted into s-polarized light, and is transmitted through plane 2 to the lens assembly 130 and the light sensor 140. Simultaneously, the p-polarized component of the incident beam is transmitted through plane 1 and strikes the (λ / 4 plate 3 + mirror) system, where it is reflected and converted into s-polarized light. This s-polarized light is reflected again by plane 1 and moves toward the (λ / 4 plate 4 + mirror) system, where it is reflected and converted into p-polarized light. This p-polarized light strikes plane 2 in the xy plane and is reflected toward lens assembly 130 and light sensor 140.

Claims

1. An imaging device (100) for imaging an object, characterized in that, The imaging device (100) includes: Optical path length extension element (120) includes: A polarization beam splitter PBS (121) is used to split an incident beam along a first sub-optical axis into a first beam and an incident beam along a perpendicular second sub-optical axis into a second beam. The first wave delayer (122a) and the first reflective element (123a) are arranged along the first sub-optical axis to delay the first beam in phase and reflect the first beam back along the first sub-optical axis; The second wave delayer (122b) and the second reflective element (123b) are arranged along the second sub-optical axis to delay the phase of the second beam and reflect the second beam back along the second sub-optical axis. The PBS (121) is further used to recombine the first beam, which is phase-delayed and reflected by the first wave delayer (122a) and the first reflective element (123a), and the second beam, which is phase-delayed and reflected by the second wave delayer (122b) and the second reflective element (123b), into an outgoing beam along the principal optical axis. Lens assembly (130) for forming an image of the object in the imaging plane of the imaging device (100) according to the outgoing beam, or for forming the incident beam for forming an image of the object in the imaging plane of the imaging device (100); An imaging sensor (140) is used to capture the image of the object in the imaging plane.

2. The imaging device (100) according to claim 1, characterized in that, The imaging device (100) further includes a lens barrel, wherein the lens barrel houses the lens assembly (130) and is movable relative to the optical path length extension element (120) and / or the imaging sensor (140) along the principal optical axis.

3. The imaging device (100) according to claim 1 or 2, characterized in that, The imaging device (100) includes one or more other optical path length extension elements (150, 220, 250) arranged along the main optical axis between the lens assembly (130) and the imaging sensor (140), wherein each other optical path length extension element (150, 220, 250) includes: Other PBSs (151, 221, 251) are used to split incident beams along other first optical axes into other first beams and incident beams along other second optical axes perpendicular to them into other second beams. Other first wave delayers (152a, 222a, 252a) and other first reflective elements (153a, 223a, 253a) are arranged along the other first sub-optical axes to delay the other first beams in phase and reflect the other first beams back along the other first sub-optical axes; Other second-wave delayers (152b, 222b, 252b) and other second-reflecting elements (153b, 223b, 253b) are arranged along the other second sub-optical axis to phase delay the other second beams and reflect the other second beams back along the other second sub-optical axis; The other PBSs (151, 221, 251) are also used to recombine the other first beams phase-delayed and reflected by the other first wave delayers (152a, 222a, 252a) and the other first reflective elements (153a, 223a, 253a) and the other second beams phase-delayed and reflected by the other second wave delayers (152b, 222b, 252b) and the other second reflective elements (153b, 223b, 253b) into an outgoing beam along the principal optical axis.

4. The imaging device (100) according to claim 3, characterized in that, The imaging device (100) includes three other optical path length extension elements (150, 220, 250) and a mirror assembly (180), wherein the optical path length extension element (120), the three other optical path length extension elements (150, 220, 250) and the mirror assembly (180) are arranged in a roof-shaped configuration.

5. The imaging apparatus (100) according to any one of the preceding claims, characterized in that, The optical path length extension element (120) also includes: Other PBS (126) are used to split the incident beam along other first optical axes into other first beams and to split the incident beam along other second optical axes perpendicular to them into other second beams. Other first wave delayers (127a) and other first reflective elements (128a) are arranged along the other first sub-optical axes to phase delay the other first beams and reflect the other first beams back along the other first sub-optical axes; Other second wave delayers (127b) and other second reflective elements (128b) are arranged along the other second sub-optical axis to phase delay the other second beam and reflect the other second beam back along the other second sub-optical axis; The other PBS (126) is also used to recombine the other first beams phase-delayed and reflected by the other first wave delayer (127a) and the other first reflective element (128a) and the other second beams phase-delayed and reflected by the other second wave delayer (127b) and the other second reflective element (128b) into other outgoing beams along the principal optical axis; The first and second sub-optical axes of the PBS (121) define a plane that is perpendicular to another plane defined by the other first and second sub-optical axes of the other PBS (126).

6. The imaging device (100) according to claim 5, characterized in that, The lens assembly is used to form the image of the object in the imaging plane of the imaging device (100) based on the outgoing beam formed by the PBS (121) and the other outgoing beams formed by the other PBS (126).

7. The imaging apparatus (100) according to any one of the preceding claims, characterized in that, The first reflective element (123a) and / or the second reflective element (123b) of the optical path length extension element (120) include a mirror or a retroreflector.

8. The imaging apparatus (100) according to any one of the preceding claims, characterized in that, The imaging device (100) includes other lens assemblies (110) arranged along the main optical axis in front of the optical path length extension element (120).

9. The imaging apparatus (100) according to claim 8, characterized in that, The other lens assembly (110) includes at least one convex lens surface.

10. The imaging apparatus (100) according to any one of the preceding claims, characterized in that, The PBS (121) comprises one or more planar layers arranged at an angle of approximately 45° relative to the first sub-optical axis and / or the second sub-optical axis.

11. The imaging apparatus (100) according to any one of the preceding claims, characterized in that, The first wave delayer (122a) and / or the second wave delayer (122b) are used to generate a 90° phase shift.

12. The imaging apparatus (100) according to claim 11, characterized in that, The first wave delayer (122a) and / or the second wave delayer (122b) include a quarter-wave plate (QWP).

13. The imaging apparatus (100) according to any one of the preceding claims, characterized in that, The imaging device (100) further includes a prism (160) which is arranged along the main optical axis between the lens assembly (130) and the imaging sensor (140) or in front of the optical path length extension element (120).

14. The imaging apparatus (100) according to any one of the preceding claims, characterized in that, The ratio of the distance between the image side of the optical path extension element (120) and the object side of the lens of the lens assembly (130) closest to the imaging sensor (140) to the effective focal length (EFL) is less than 0.

6.

15. An electronic device, characterized in that, Specifically, it is a smartphone or tablet computer, including the imaging device (100) according to any one of the preceding claims.

Images