Image acquisition module and view finding device

Abstract

The utility model discloses an image acquisition module and framing equipment. The image acquisition module is used for framing a target framing object. Wherein the image acquisition module comprises a reflector, a lens assembly and an image sensor, and the reflector, the lens assembly and the image sensor are sequentially arranged along the optical axis of the lens assembly. Wherein the reflecting surface of the reflecting mirror is arranged towards the lens assembly, and the reflecting surface is a curved surface. The reflecting surface is used for reflecting the light at the target framing object to the lens assembly, and the lens assembly is used for refracting the light emitted by the reflecting mirror to the image sensor. The image acquisition module provided by the utility model adopts a catadioptric optical path architecture, so that the image distortion degree can be obviously reduced, the field angle is enlarged, and the chromatic aberration is reduced.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and more specifically, to an image acquisition module and a framing device. Background Technology

[0002] With the continuous development of imaging technology, a wide variety of camera devices (such as action cameras, mirrorless cameras, and SLR cameras) have emerged on the market to meet the diverse shooting needs of users.

[0003] However, existing camera equipment suffers from severe image distortion. Utility Model Content

[0004] This application provides an image acquisition module and a framing device.

[0005] According to a first aspect of this application, embodiments of this application provide an image acquisition module for framing a target object. The image acquisition module includes a reflector, a lens assembly, and an image sensor, which are sequentially arranged along the optical axis of the lens assembly. The reflective surface of the reflector faces the lens assembly and is curved. The reflective surface reflects light from the target object to the lens assembly, and the lens assembly refracts the light emitted through the reflector to the image sensor.

[0006] In some possible embodiments, the reflecting surface of the mirror is an even-order aspherical surface or a freeform surface.

[0007] In some possible embodiments, the image reduction ratio of the image acquisition module is greater than or equal to 500; or / and the aspect ratio of the image acquisition module is less than or equal to 0.1.

[0008] In some possible embodiments, the center of the image sensor is offset from the optical axis of the lens assembly; the reflective surface is asymmetrically arranged about the optical axis of the lens assembly.

[0009] In some possible embodiments, the reflective surface includes an adjacent first sub-reflective surface and a second sub-reflective surface, which are located on opposite sides of the optical axis of the lens assembly, and the area of ​​the first sub-reflective surface is larger than the area of ​​the second sub-reflective surface; the first sub-reflective surface and the image sensor are located on opposite sides of the optical axis.

[0010] In some possible embodiments, the lens assembly includes a first lens group, an aperture stop, and a second lens group; the first lens group, the aperture stop, and the second lens group are arranged sequentially on the optical axis of the lens assembly along a specified direction, which is the direction in which the image sensor points to the reflector.

[0011] In some possible embodiments, the first lens group adopts a telecentric optical path architecture.

[0012] In some possible embodiments, the first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially in a specified direction; the first lens has positive optical power, the light-emitting surface of the first lens is concave, and the light-incident surface of the first lens is convex; the second lens has positive optical power, the light-emitting surface of the second lens is convex, and the light-incident surface of the second lens is concave; the third lens has negative optical power, the light-emitting surface of the third lens is concave, and the light-incident surface of the third lens is concave; the fourth lens has positive optical power, the light-emitting surface of the fourth lens is convex, and the light-incident surface of the fourth lens is convex.

[0013] In some possible embodiments, both the light-emitting surface and the light-receiving surface of the first lens are even-order aspherical surfaces.

[0014] In some possible embodiments, the optical power of the first lens group is greater than 0 and less than or equal to 0.25, and / or the optical power of the second lens group is greater than or equal to -1.2 and less than or equal to -0.7.

[0015] In some possible embodiments, the second lens group includes a fifth lens and a sixth lens arranged sequentially in a specified direction; the fifth lens has negative optical power, the light-emitting surface of the fifth lens is planar, and the light-incident surface of the fifth lens is concave; the sixth lens has negative optical power, the light-emitting surface of the sixth lens is concave, and the light-incident surface of the sixth lens is concave.

[0016] In some possible embodiments, the light-emitting surface and the light-receiving surface of the sixth lens are both even-order aspherical surfaces.

[0017] According to a second aspect of this application, embodiments of this application also provide a framing device, which includes a housing and the aforementioned image acquisition module, the image acquisition module being disposed within the housing.

[0018] This application provides an image acquisition module and a framing device. The image acquisition module is used to frame a target object. The image acquisition module includes a reflector, a lens assembly, and an image sensor. Light from the target object is reflected by the reflector and refracted by the lens assembly before entering the image sensor.

[0019] The image acquisition module in this application adopts a catadioptric optical path architecture. Specifically, the optical path architecture of the image acquisition module includes both reflective optical elements (i.e., mirrors) and refractive optical elements (i.e., lens assemblies). The lens assemblies can magnify the image and correct system aberrations. Specifically, the reflecting surface of the mirror is curved, which allows the mirror to reduce image distortion and expand the field of view.

[0020] Furthermore, since a reflector is included in the optical path architecture of the image acquisition module, the presence of the reflector reduces the number of refractive lenses in the lens assembly, thereby effectively avoiding the generation of unnecessary chromatic aberration and improving the imaging quality of the image acquisition module. It is easy to understand that since chromatic aberration is caused by the dispersion of the refractive material of the refractive lens itself, reducing the number of refractive lenses will also reduce chromatic aberration.

[0021] Furthermore, in related technologies, researchers typically design the surface shape and number of refractive lenses in lens assemblies to enable the optical system to achieve a larger field of view. However, with an expanded field of view, the lens assembly faces difficulties in aberration correction. In this application, since the reflector added to the optical path can expand the field of view, the lens assembly in the subsequent optical path does not need to achieve a large field of view. In other words, this application uses a curved reflector to "take on" the function of expanding the field of view, thereby avoiding the problems of aberration correction difficulties and increased complexity of the optical path architecture that arise with the lens assembly. This allows the image acquisition module to successfully correct aberrations while reducing the design difficulty of the lens assembly, and its overall optical path architecture can be simpler and more compact.

[0022] In summary, the image acquisition module in this application adopts a "flip-reflection" optical path architecture, which can significantly reduce image distortion, expand the field of view and reduce chromatic aberration. Its own optical path architecture is also relatively simple and compact, which is conducive to the miniaturization and lightweight structural design of the viewfinder device equipped with this image acquisition module. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the framing device provided in the embodiments of this application.

[0025] Figure 2 yes Figure 1 The diagram shows the structure of the image acquisition module in the viewfinder device.

[0026] Figure 3 yes Figure 2 The image acquisition module shown is a simulation diagram of the optical path.

[0027] Figure 4 yes Figure 3A magnified view of a portion of the image.

[0028] Figure 5 yes Figure 2 The diagram shows the structure of the lens assembly in the image acquisition module.

[0029] Figure 6 yes Figure 2 The image shown is a curve of light field bending and distortion corresponding to the image acquisition module.

[0030] Figure 7 yes Figure 2 The image acquisition module shown is the corresponding imaging simulation result diagram. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0032] This application provides an image acquisition module 100 and a framing device 200 configured with the image acquisition module 100, wherein the framing device 200 is a device for framing a target object. In some embodiments, the target object can be a framing space, which can change as the position of the framing device 200 moves. In other possible embodiments, the target object can be a framing surface, and the framing device 200 can be positioned at a specified location to frame a specific framing surface. The framing surface can be a plane or a curved surface (e.g., a quadratic surface, a freeform surface, etc.). Specifically, when framing the target object, the framing device 200 is positioned to the side of the target object (e.g., the left side, the right side, etc.), that is, the framing device 200 adopts a "side framing" method, which can avoid the framing device 200 obstructing the view of people directly in front of the target object, thus ensuring the viewing experience of relevant personnel.

[0033] In some possible embodiments, the framing device 200 can be applied to a color picking system. Specifically, the target framing object can be a viewing surface, such as a television screen, computer screen, or monitor. Taking a television screen as an example, the framing device 200 can be a camera, which can be positioned on the side of the television screen and can acquire the television image being played in real time, enabling the color picking system to determine the color information of the television image based on it. Furthermore, the color picking system can also include lighting fixtures, which can synchronously adjust the color of the lighting fixtures based on the color information of the television image to enhance the user's viewing experience.

[0034] In some possible embodiments, the framing device 200 can be applied in a surveillance system. Specifically, the target framing object can be a viewing surface, such as a television screen, computer screen, or monitor. Taking a television screen as an example, the framing device 200 can be a camera. The framing device 200 can be positioned on the side of the television screen and can acquire the television image played on the screen in real time. This allows the surveillance system to turn off or switch the playback channel when specific content (e.g., advertisements, scenes unsuitable for children) appears on the television screen, ensuring a more comfortable viewing experience for the user.

[0035] It's easy to understand here that when the viewfinder 200 is framing a curved screen, the corresponding framing surface is curved; when the viewfinder 200 is framing a flat screen, the corresponding framing surface is flat.

[0036] In some possible embodiments, the viewfinder 200 can be applied to a motion capture system for virtual keys. For example, the motion capture system for virtual keys can be applied to a laser projection keyboard, which can project a virtual keyboard onto a viewfinder surface (e.g., a desktop). The viewfinder 200 can acquire real-time images of the user's gestures on the virtual keyboard, allowing the laser projection keyboard to determine the user's click position on the virtual keyboard based on these gesture images.

[0037] In some possible embodiments, the framing device 200 can be applied to an in-vehicle framing camera system. Specifically, the target framing object can be the framing space, for example, the framing space can be the driving space in front of the vehicle, or the reversing space behind the vehicle, etc.

[0038] Please see Figure 1The viewfinder device 200 may include a housing 210 and an image acquisition module 100. The image acquisition module 100 is disposed within the housing 210 and is used to frame the target object. The housing 210 provides installation space for accommodating the image acquisition module 100 and serves to fix and protect the image acquisition module 100.

[0039] In some possible embodiments, the housing 210 may also be provided with a viewfinder 2120, through which light from the target object is incident on the image acquisition module 100, so that the image acquisition module 100 can successfully capture the target object.

[0040] Please see Figure 2 The image acquisition module 100 may include a reflector 30, a lens assembly 40 and an image sensor 50, which are arranged sequentially along the optical axis of the lens assembly 40.

[0041] It should be noted that the phrase "arranged sequentially along the optical axis of the lens assembly 40" defines the arrangement order of the reflector 30, lens assembly 40, and image sensor 50 along the optical axis. It should not be interpreted merely as defining the relative positions of the reflector 30 and image sensor 50 with respect to the optical axis, nor does it imply that every element must intersect the optical axis. Specifically, taking the image sensor 50 as an example, the image sensor 50 can be positioned on the optical axis; for instance, the geometric center of the photosensitive surface of the image sensor 50 can coincide with the optical axis, or the geometric center of the photosensitive surface of the image sensor 50 can be offset from the optical axis. The image sensor 50 can also be positioned to one side of the optical axis, without spatial overlap with it. Specifically, the "relative positions of the reflector 30 and image sensor 50 with respect to the optical axis" will be described later in the specification.

[0042] In this embodiment, the reflective surface 320 of the reflector 30 is disposed facing the lens assembly 40, and the reflective surface 320 is curved. The reflective surface 320 is used to reflect light from the target object to the lens assembly 40, and the lens assembly 40 is used to refract the light emitted through the reflector 30 to the image sensor 50. That is, the light from the target object is incident on the image sensor 50 after being reflected by the reflector 30 and refracted by the lens assembly 40 in sequence.

[0043] In this embodiment, the image acquisition module 100 adopts a "flip-reflection" optical path architecture. Specifically, the optical path architecture of the image acquisition module 100 includes both reflective optical elements (i.e., reflector 30) and refractive optical elements (i.e., lens assembly 40). The lens assembly 40 can magnify the image and correct system aberrations. Because the reflecting surface 320 of the reflector 30 is curved, the reflector 30 can reduce image distortion and expand the field of view.

[0044] Furthermore, since a reflector 30 is provided in the optical path architecture corresponding to the image acquisition module 100, the presence of the reflector 30 can reduce the number of refractive lenses in the lens assembly 40, thereby effectively avoiding the generation of unnecessary chromatic aberration and improving the imaging quality of the image acquisition module 100. It is easy to understand that since chromatic aberration is caused by the dispersion of the refractive material of the refractive lens itself, the chromatic aberration will also decrease when the number of refractive lenses is reduced.

[0045] Furthermore, in related technologies, researchers typically design the surface shape and number of refractive lenses in lens assemblies to enable the optical system to achieve a larger field of view. However, with an expanded field of view, the lens assembly faces difficulties in aberration correction. In this application, since the reflector 30 added to the optical path can expand the field of view, the lens assembly 40 in the subsequent optical path does not need to achieve a large field of view. In other words, this application uses a curved reflector to "take on" the function of expanding the field of view, thereby avoiding the problems of aberration correction difficulties and increased complexity of the optical path architecture in the lens assembly 40. This allows the image acquisition module 100 to successfully correct aberrations while reducing the design difficulty of the lens assembly 40, and its overall optical path architecture can be simpler and more compact.

[0046] In summary, the image acquisition module 100 in this embodiment adopts a "flip-reflection" optical path architecture, which can significantly reduce image distortion, expand the field of view and reduce chromatic aberration. Its own optical path architecture is also relatively simple and compact, which is conducive to the miniaturization and lightweight structural design of the viewfinder device 200 equipped with the image acquisition module 100.

[0047] It is not difficult to see here that, Figure 2 In this image acquisition module 100, the target object is the viewfinder surface. Due to the presence of the reflector 30, the viewfinder surface is completely offset from the optical axis of the lens assembly 40, located on one side of the optical axis of the lens assembly 40; that is, the viewfinder surface does not coincide with the optical axis. Therefore, the viewfinder device 200 equipped with this image acquisition module 100 can adopt a "side-viewing" framing method.

[0048] Please see Figure 3 and Figure 4This illustrates a simulation diagram of the light at the viewfinder surface in the image acquisition module 100. It should be noted here that... Figure 4 The reflector and image sensor in the text only represent their arrangement on the optical axis, and do not limit the specific shape of the reflector 30 and the image sensor 50 or their relative positional relationship with the optical axis.

[0049] Combination Figure 3 and Figure 4 The image acquisition module 100 in this embodiment has a large image reduction ratio. Here, the image reduction ratio refers to the size ratio of the viewing surface and the imaging surface in the same direction. Specifically, the image acquisition module 100 in this embodiment can "compress" a large viewing surface to a very small imaging surface. Here, the "imaging surface" can be understood as the photosensitive surface of the image sensor 50.

[0050] In some possible embodiments, the image reduction ratio of the image acquisition module 100 can be greater than or equal to 500. Therefore, the image acquisition module 100 in this embodiment has a large field of view and can acquire more image information in the viewfinder.

[0051] In one implementation, the image sensor 50 can use a 1 / 5-inch chip, corresponding to an object height of 1.92mm. Here, "1.92mm" can be understood as the vertical dimension of the imaging surface (e.g., the width of the image). The viewing area can be 1359mm × 1019mm, which can cover the space occupied by a 65-inch television screen. Here, "1359mm" can be understood as the horizontal dimension of the viewing surface (e.g., the length of the image), and "1019mm" can be understood as the vertical dimension of the viewing surface (e.g., the width of the image). Therefore, the image reduction ratio of the image acquisition module 100 in this embodiment is equal to 1019mm divided by 1.92mm, which is approximately 531. Of course, the image sensor 50 can also use chips of other sizes (e.g., 1 / 3-inch, 1 / 4-inch), and this embodiment does not specifically limit its size.

[0052] exist Figure 3 and Figure 4 In this system, the light rays on the viewfinder and the image sensor are in one-to-one correspondence, and different colors of light correspond to different field of view angles. Specifically, in Figure 3 In this context, the greater the distance between the light source on the viewing surface and the image acquisition module 100, the larger the field of view.

[0053] In some possible embodiments, the half-field-of-view angle of the image acquisition module 100 can be greater than or equal to 80 degrees and less than 90 degrees. Here, "half-field-of-view angle" can be understood as the angle between the direction of propagation of the light ray located on the viewing surface and at its greatest distance from the image acquisition module 100, and the optical axis of the lens assembly 40. Therefore, the image acquisition module 100 in this embodiment has an extremely large half-field-of-view angle (close to 90 degrees) to ensure that the image acquisition module 100 can capture more image information from the viewing surface.

[0054] In some possible embodiments, the aspect ratio of the image acquisition module 100 is less than or equal to 0.1. Here, the aspect ratio refers to the ratio between the viewing distance and the width of the viewfinder. Specifically, the viewing distance refers to the distance on the optical axis between the reflector 30 and the plane containing the viewfinder. Please refer again. Figure 2 The framing distance is Figure 2 The length d in the image is the width of the viewfinder. Figure 2 The length L in the middle.

[0055] In one implementation, the size of the viewing area can be 1359mm × 1019mm, where "1019mm" corresponds to the width of the viewing area. The distance d between the reflector 30 and the plane containing the viewing area on the optical axis can be 37.703mm. Therefore, the aspect ratio of the image acquisition module 100 in this embodiment is equal to 37.703mm divided by 1019mm, which equals 0.037.

[0056] Therefore, the image acquisition module 100 in this embodiment has a very small aspect ratio, enabling the viewfinder device 200 equipped with the image acquisition module 100 to perform ultra-short-focus framing. Furthermore, since the reflective surface 320 is curved, when the viewfinder device 200 equipped with the image acquisition module 100 is used in ultra-short-focus scenarios, the degree of image distortion can be significantly reduced.

[0057] The specific implementation method of the image acquisition module 100 is explained below.

[0058] In this embodiment, the reflector 30 is used to reflect light from the target object to the lens assembly 40. The reflecting surface 320 of the reflector 30 is curved, which allows the reflector 30 to reduce image distortion and expand the field of view. Specifically, the reflector 30 in this embodiment can correct 90% of trapezoidal distortion and other distortions, eliminating the need for subsequent software correction of the image captured by the image sensor 50, thus saving hardware computing power of the viewfinder device 200 equipped with the image acquisition module 100.

[0059] Furthermore, since the reflector 30 can significantly change the direction of the light path compared to the refracting lens, its presence allows for more efficient and wider-angle adjustment of the light in the optical system. Therefore, by incorporating the reflector 30, the optical performance of the image acquisition module 100 can be improved more efficiently.

[0060] In some possible embodiments, the optical power of the reflective surface 320 can be 0.50783 ± 0.0863.

[0061] In some possible embodiments, the reflecting surface 320 of the reflector 30 can be an even-order aspherical surface. Since even-order aspherical surfaces possess rotational symmetry, the assembly difficulty of the reflector 30 along the optical axis can be reduced, thus ensuring the overall optical accuracy of the image acquisition module 100. Furthermore, even-order aspherical surfaces are easier to manufacture, which can reduce the manufacturing cost of the reflector 30.

[0062] Please refer to Table-1, which shows the even-order aspherical coefficients corresponding to the reflective surface 320 provided in this embodiment.

[0063] Table 1

[0064] order Level 4 Level 6 Level 8 Level 10 Level 12 Level 14 Level 16 coefficient value -1.85E-04 -8.95E-08 -1.25E-09 4.90E-12 2.74E-14 -1.01E-16 -4.60E-18

[0065] For example, "-1.85E-04" refers to the coefficient value of the 4th order in the even-order aspheric surface corresponding to the reflecting surface 320, and "2.74E-14" refers to the coefficient value of the 12th order in the even-order aspheric surface corresponding to the reflecting surface 320.

[0066] In some other possible embodiments, the reflecting surface 320 of the reflector 30 can be a freeform surface. Since the curvature of each region on the freeform surface can be flexibly adjusted, aberrations and distortions can be reduced more effectively, thereby improving the imaging quality of the image acquisition module 100.

[0067] In some possible embodiments, the reflector 30 is asymmetrically arranged about the optical axis of the lens assembly 40. For example, the entire structure of the reflector 30 can be located on one side of the optical axis; or, most of the structure of the reflector 30 can be located on one side of the optical axis, and the remaining structure of the reflector 30 can be located on the other side of the optical axis. This arrangement of the reflector 30 reduces the space it occupies and prevents it from blocking light when light from the target object enters the reflector 30 from the other side of the optical axis, thus acting as a "blind spot" to ensure smooth light propagation.

[0068] Furthermore, since the light from the target object is reflected almost entirely on one side of the optical axis by the reflector 30, the light is subsequently refracted by the lens assembly 40 and enters the image sensor 50 from the other side of the optical axis. Therefore, in this embodiment, the image sensor 50 is offset from the optical axis of the lens assembly 40 to achieve efficient utilization of the photosensitive area of ​​the image sensor 50. It should be noted that "the image sensor 50 is offset from the optical axis of the lens assembly 40" means that the center of the image sensor 50 is offset from the optical axis of the lens assembly 40, and the "center of the image sensor 50" can refer to the geometric center of the photosensitive surface of the image sensor 50. Therefore, in this embodiment, the geometric center of the photosensitive surface of the image sensor 50 does not coincide with the optical axis. If the geometric center of the photosensitive surface were set on the optical axis, half of the photosensitive surface would not receive light, resulting in a waste of the photosensitive area.

[0069] In one implementation, most of the structure of the reflector 30 can be disposed on one side of the optical axis, and the remaining structure of the reflector 30 can be disposed on the other side of the optical axis, so that the reflecting surface 320 is asymmetrically arranged about the optical axis of the lens assembly 40. See also... Figure 5 The reflecting surface 320 of the reflector 30 may include an adjacent first sub-reflecting surface 3210 and a second sub-reflecting surface 3230, which are located on opposite sides of the optical axis of the lens assembly 40. It should be noted that the "first sub-reflecting surface 3210 and the second sub-reflecting surface 3230" can be two different regions on the reflecting surface 320, separated by the optical axis. In practical applications, there is no clear dividing line between the first sub-reflecting surface 3210 and the second sub-reflecting surface 3230; they can smoothly transition to jointly define the reflecting surface 320.

[0070] Specifically, the area of ​​the first sub-reflective surface 3210 is larger than the area of ​​the second sub-reflective surface 3230. Therefore, the first sub-reflective surface 3210 is used to reflect most of the light from the target object to the lens assembly 40, and the second sub-reflective surface 3230 is used to reflect a small portion of the light from the target object to the lens assembly 40.

[0071] exist Figure 5 In the illustrated embodiment, the first sub-reflective surface 3210 and the image sensor 50 are located on opposite sides of the optical axis. Specifically, the photosensitive surface of the image sensor 50 does not intersect the optical axis, allowing almost the entire area of ​​the photosensitive surface to receive light emitted from the lens assembly 40, thereby maximizing the utilization of the photosensitive area of ​​the image sensor 50.

[0072] As another implementation, all the structures of the reflector 30 can be arranged on the same side of the optical axis, with the reflector 30 and the image sensor 50 located on opposite sides of the optical axis, so as to maximize the utilization of the photosensitive area of ​​the image sensor 50.

[0073] In this embodiment, the image sensor 50 and the reflector 30 are respectively disposed on opposite sides of the lens assembly 40. The image sensor 50 is used to image the light emitted through the lens assembly 40. Specifically, the photosensitive surface of the image sensor 50 may be perpendicular to the optical axis of the lens assembly 40. Exemplarily, the image sensor 50 may be a CMOS sensor chip or a CCD sensor chip.

[0074] exist Figure 5 In the illustrated embodiment, the image acquisition module 100 may further include a light-transmitting protective element 60, which may be attached to the photosensitive surface of the image sensor 50 to protect the image sensor 50. Specifically, the light-transmitting protective element 60 may be a flat glass plate.

[0075] In some possible embodiments, an infrared filter film (not shown) may also be deposited on the side of the light-transmitting protective member 60 away from the image sensor 50. This infrared filter film is used to filter out infrared light in the light to eliminate the influence of infrared light on the imaging quality.

[0076] In this embodiment, the lens assembly 40 is disposed in the optical path of the light rays emitted via the reflector 30, and is used to refract the light rays to the image sensor 50. Specifically, the lens assembly 40 may include multiple refractive lenses to magnify the image and correct system aberrations.

[0077] exist Figure 5 In the illustrated embodiment, the lens assembly 40 may include a first lens group 410, an aperture stop 430, and a second lens group 450. The first lens group 410, aperture stop 430, and second lens group 450 are sequentially arranged along a designated direction X on the optical axis of the lens assembly 40, where X is the direction from the image sensor 50 to the reflector 30. Specifically, light rays emitted from the reflector 30 pass sequentially through the second lens group 450, the aperture stop 430, and the first lens group 410 before entering the image sensor 50. In some other possible embodiments, the aperture stop in the lens assembly 40 may be omitted; instead, it may be a lens group formed by multiple refracting lenses, thereby reducing the hardware cost of the lens assembly 40 and making its overall design more compact.

[0078] In this embodiment, the first lens group 410 adopts a telecentric optical path architecture, enabling the principal ray to propagate almost parallel to the optical axis of the lens assembly 40 to correct system aberrations. In some possible embodiments, the optical power of the first lens group 410 is greater than 0 and less than or equal to 0.25. Therefore, the optical power of the first lens group 410 in this embodiment is relatively small, which is beneficial for reducing the generation of aberrations. Specifically, the first lens group 410 may include a first lens 4120, a second lens 4140, a third lens 4160, and a fourth lens 4180 arranged sequentially in a specified direction X.

[0079] Specifically, the light emitted through the aperture stop 430 passes sequentially through the fourth lens 4180, the third lens 4160, the second lens 4140, and the first lens 4120 before entering the image sensor 50. Therefore, in this embodiment, the first lens group 410 adopts a four-lens optical path architecture, which makes the first lens group 410 simpler and more compact, thereby achieving a miniaturized design of the lens assembly 40. Of course, in some other possible embodiments, the first lens group 410 may also adopt a three-lens optical path architecture, for example, using the first lens 4120, the second lens 4140, and the third lens 4160 together to form the first lens group 410; or it may adopt a five- or even six-lens optical path architecture. This embodiment does not specifically limit the number of refractive lenses in the first lens group 410.

[0080] exist Figure 5 In the illustrated embodiment, the first lens 4120 has positive optical power, which can converge light rays. The light-emitting surface S4 of the first lens 4120 is concave, and the light-incident surface S5 is convex. Specifically, the optical power of the first lens 4120 can range from 0.053957 ± 0.0092.

[0081] In some possible embodiments, the light-emitting surface S4 and the light-incident surface S5 of the first lens 4120 are both even-order aspherical surfaces. Since the first lens 4120 is the lens closest to the image sensor 50 in the lens assembly 40, the use of even-order aspherical surfaces for its light-emitting surface S4 and light-incident surface S5 can improve the imaging quality of the lens assembly 40. Specifically, when the first lens 4120 uses even-order aspherical surfaces, it can focus according to the position and angle of light incidence, thereby improving the sharpness and resolution of the image.

[0082] Please refer to Table 2, which shows the even-order aspherical coefficients corresponding to the light-emitting surface S4 and the light-incident surface S5 of the first lens 4120 provided in this embodiment.

[0083] Table 2

[0084] Face number Level 4 Level 6 S4 9.23E-03 -1.02E-03 S5 3.40E-02 1.39E-03

[0085] For example, "9.23E-03" refers to the fourth-order coefficient value in the even-order aspherical surface corresponding to the light-emitting surface S4 of the first lens 4120, and "1.39E-03" refers to the sixth-order coefficient value in the even-order aspherical surface corresponding to the light-incident surface S5 of the first lens 4120.

[0086] exist Figure 5 In the illustrated embodiment, the second lens 4140 has positive optical power, which can converge light rays. The light-emitting surface S6 of the second lens 4140 is convex, and the light-incident surface S7 is concave. This embodiment does not limit the specific surface shapes of the light-emitting surface S6 and the light-incident surface S7 of the second lens 4140. For example, the light-emitting surface S6 and the light-incident surface S7 of the second lens 4140 can be quadratic surfaces (e.g., ellipsoidal, hyperboloid, parabolic, etc.) to reduce the manufacturing cost of the second lens 4140. Specifically, the optical power of the second lens 4140 can be in the range of 0.10049 ± 0.0171.

[0087] exist Figure 5 In the illustrated embodiment, the third lens 4160 has a negative optical power, which can diverge light. The light-emitting surface S8 and the light-incident surface S9 of the third lens 4160 are both concave. This embodiment does not limit the specific surface shapes of the light-emitting surface S8 and the light-incident surface S9 of the third lens 4160. For example, the light-emitting surface S8 and the light-incident surface S9 of the third lens 4160 can be quadratic surfaces (e.g., ellipsoidal, hyperboloid, parabolic, etc.) to reduce the manufacturing cost of the third lens 4160. Specifically, the optical power range of the third lens 4160 can be -0.27889 ± 0.0474.

[0088] exist Figure 5 In the illustrated embodiment, the fourth lens 4180 has positive optical power, which can converge light rays. The light-emitting surface S10 and the light-incident surface S11 of the fourth lens 4180 are both convex. This embodiment does not limit the specific surface shapes of the light-emitting surface S10 and the light-incident surface S11 of the fourth lens 4180. For example, the light-emitting surface S10 and the light-incident surface S11 of the fourth lens 4180 can be quadratic surfaces (e.g., ellipsoidal, hyperboloid, parabolic, etc.) to reduce the manufacturing cost of the fourth lens 4180. Specifically, the optical power of the fourth lens 4180 can be in the range of 0.24434 ± 0.0415. Therefore, Figure 5 The optical power of the first lens group 410 is greater than or equal to 0.004697 and less than or equal to 0.235097.

[0089] It should be noted that, due to the relatively small overall size of the image acquisition module 100 in this embodiment, the first lens 4120, the second lens 4140, the third lens 4160, and the fourth lens 4180 are not designed to be tightly fitted together, or none of the lenses are cemented lenses. Specifically, the first lens 4120, the second lens 4140, the third lens 4160, and the fourth lens 4180 are spaced apart on the optical axis, and there may be gaps between adjacent lenses; or, adjacent lenses may be stacked on top of each other without any optical adhesive between them, in order to save installation space for the image acquisition module 100.

[0090] exist Figure 5 In the illustrated embodiment, the aperture stop 430 is positioned between the first lens group 410 and the second lens group 450, which can eliminate stray light and improve the imaging quality of the lens assembly 40. Specifically, the radius of the light-transmitting hole on the aperture stop 430 can be greater than or equal to 1.2 mm and less than or equal to 1.8 mm. For example, radii of 1.2 mm, 1.5 mm, 1.8 mm, etc.

[0091] In this embodiment, the optical power of the second lens group 450 is greater than or equal to -1.2 and less than or equal to -0.7. Therefore, the second lens group 450 in this embodiment has a large negative optical power, so that light rays emitted from different positions on the reflecting surface 320 at different deflection angles can propagate to the position of the aperture stop 430 under the action of the second lens group 450, thus ensuring the smooth propagation of light. Specifically, the second lens group 450 may include a fifth lens 4520 and a sixth lens 4540 arranged sequentially in a specified direction X.

[0092] Specifically, the light rays emitted from the reflector 30 pass sequentially through the sixth lens 4540 and the fifth lens 4520 before entering the aperture stop 430. Therefore, in this embodiment, the second lens group 450 adopts a two-refractive-lens optical path architecture, which makes the second lens group 450 simpler and more compact, thereby achieving a miniaturized design of the lens assembly 40. Of course, in some other possible embodiments, the second lens group 450 may also adopt a three- or even four-refractive-lens optical path architecture. This embodiment does not specifically limit the number of refractive lenses in the second lens group 450.

[0093] exist Figure 5In the illustrated embodiment, the fifth lens 4520 has a negative optical power, which can diverge light. The light-emitting surface S13 of the fifth lens 4520 is planar, and the light-incident surface S14 is concave. This embodiment does not limit the specific shape of the light-incident surface S14 of the fifth lens 4520. For example, the light-incident surface S14 of the fifth lens 4520 can be a quadratic surface (e.g., an ellipsoid, hyperboloid, paraboloid, etc.) to reduce the manufacturing cost of the fifth lens 4520. Specifically, the optical power range of the fifth lens 4520 can be -0.032839 ± 0.0056.

[0094] exist Figure 5 In the illustrated embodiment, the sixth lens 4540 has a negative optical power, which can diverge light. The light-emitting surface S15 of the sixth lens 4540 is concave, and the light-receiving surface S16 of the sixth lens 4540 is also concave. Specifically, the optical power of the sixth lens 4540 can range from -0.89997 ± 0.1530. Therefore, Figure 5 The optical power of the second lens group 450 is greater than or equal to -1.091409 and less than or equal to -0.774209.

[0095] In some possible embodiments, the light-emitting surface S15 and the light-incident surface S16 of the sixth lens 4540 are both even-order aspherical surfaces. Since the sixth lens 4540 is the lens closest to the reflecting mirror 30 in the lens assembly 40, the design of its light-emitting surface S15 and light-incident surface as even-order aspherical surfaces can improve the imaging quality of the lens assembly 40. Specifically, when the sixth lens 4540 is entirely composed of even-order aspherical surfaces, it can focus according to the position and angle of light incidence, thereby improving the sharpness and resolution of the image.

[0096] Please refer to Table 3, which shows the even-order aspherical coefficients corresponding to the light-emitting surface S15 and the light-incident surface S16 of the sixth lens 4540 provided in this embodiment.

[0097] Table 3

[0098] Face number Level 4 Level 6 Level 8 S15 1.07E-02 2.11E-03 -1.37E-03 S16 -1.49E-03 -7.23E-04 -5.85E-05

[0099] For example, "1.07E-02" refers to the fourth-order coefficient value in the even-order aspherical surface corresponding to the light-emitting surface S15 of the sixth lens 4540, and "-5.85E-05" refers to the eighth-order coefficient value in the even-order aspherical surface corresponding to the light-receiving surface S16 of the sixth lens 4540.

[0100] It should be noted that, due to the relatively small overall size of the image acquisition module 100 in this embodiment, neither the fifth lens 4520 nor the sixth lens 4540 employs a tightly fitted design, or neither of the lenses is a cemented lens. Specifically, the fifth lens 4520 and the sixth lens 4540 can be spaced apart on the optical axis, with a gap between them; or, the fifth lens 4520 and the sixth lens 4540 can be stacked on top of each other without any optical adhesive, in order to save installation space for the image acquisition module 100.

[0101] Please refer to Table 4, which shows the optical parameters of the image sensor 50, light-transmitting protective element 60, first lens 4120, second lens 4140, third lens 4160, fourth lens 4180, aperture stop 430, fifth lens 4520, sixth lens 4540 and reflector 30 provided in this embodiment.

[0102] Table 4

[0103]

[0104] It should be noted that in Table 4, "S1" refers to the photosensitive surface of the image sensor 50; "S2 and S3" refer to the light-emitting surface and light-receiving surface of the light-transmitting protective element 60; "S12" refers to the plane where the light-transmitting aperture 430 is located; and "S17" refers to the reflective surface 320 of the mirror 30. The "Material" column displays the grade of the different types of glass used in different optical elements; for example, "K4A" indicates that the light-transmitting protective element 60 is made of crown glass of grade K4A; "H-LAF3" indicates that the sixth lens 4540 is made of lanthanum crown glass of grade H-LAF3; and "MIRROR" indicates that the mirror 30 is made of mirror glass.

[0105] Please see Figure 6 It shows the light field bending and distortion curves corresponding to the image acquisition module 100 provided in this embodiment. Among them, Figure 6 The middle section (a) corresponds to the field curve of the image acquisition module 100. The three solid lines represent the meridional image plane curvature at wavelengths of 656.3 nm, 587.6 nm and 486.1 nm, respectively, and the three dashed lines represent the sagittal image plane curvature at wavelengths of 656.3 nm, 587.6 nm and 486.1 nm, respectively. Figure 6 Part (b) corresponds to the distortion curves of the image acquisition module 100. The three curves represent the distortion values ​​at different image heights at wavelengths of 656.3 nm, 587.6 nm, and 486.1 nm, respectively. Figure 6It is easy to see that the optical distortion value is less than 10%. Therefore, the imaging distortion of the image acquisition module 100 in this embodiment is relatively small.

[0106] Please see Figure 7 The diagram shows the imaging simulation results corresponding to the image acquisition module 100 provided in this embodiment. The object height is 1.92 mm; the field position is 1.1 mm; and the image size is 1359.1054 mm * 1019.3291 mm. Figure 7 It is easy to see that the image has a small degree of distortion and almost no color difference or aberration.

[0107] This application provides an image acquisition module 100 and a viewfinder device 200 configured with the image acquisition module 100. The image acquisition module 100 may include a reflector 30, a lens assembly 40, and an image sensor 50, which are arranged sequentially along the optical axis of the lens assembly 40. Specifically, the reflecting surface 320 of the reflector 30 faces the lens assembly 40 and is curved. The reflecting surface 320 reflects light from the target object to the lens assembly 40, and the lens assembly 40 refracts the light emitted from the reflector 30 to the image sensor 50. In other words, light from the target object is reflected by the reflector 30 and refracted by the lens assembly 40 before entering the image sensor 50.

[0108] In this embodiment, the image acquisition module 100 adopts a "flip-reflection" optical path architecture. Specifically, the optical path architecture of the image acquisition module 100 includes both reflective optical elements (i.e., reflector 30) and refractive optical elements (i.e., lens assembly 40). The lens assembly 40 can magnify the image and correct system aberrations. Because the reflecting surface 320 of the reflector 30 is curved, the reflector 30 can reduce image distortion and expand the field of view.

[0109] Furthermore, since a reflector 30 is provided in the optical path architecture corresponding to the image acquisition module 100, the presence of the reflector 30 can reduce the number of refractive lenses in the lens assembly 40, thereby effectively avoiding the generation of unnecessary chromatic aberration and improving the imaging quality of the image acquisition module 100. It is easy to understand that since chromatic aberration is caused by the dispersion of the refractive material of the refractive lens itself, the chromatic aberration will also decrease when the number of refractive lenses is reduced.

[0110] Furthermore, since the reflector 30 added to the optical path can expand the field of view, the lens assembly 40 in the subsequent optical path does not need to achieve a large field of view. In other words, this application uses a curved reflector to "undertake" the function of expanding the field of view, thereby avoiding problems such as aberration correction difficulties and increased complexity of the optical path architecture in the lens assembly 40. This allows the image acquisition module 100 to successfully correct aberrations while reducing the design difficulty of the lens assembly 40, and its overall optical path architecture can be simpler and more compact.

[0111] In summary, the image acquisition module 100 in this embodiment adopts a "flip-reflection" optical path architecture, which can significantly reduce image distortion, expand the field of view and reduce chromatic aberration. Its own optical path architecture is also relatively simple and compact, which is conducive to the miniaturization and lightweight structural design of the viewfinder device 200 equipped with the image acquisition module 100.

[0112] In this application specification, certain terms are used to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. The specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" throughout the specification and claims is an open-ended term and should be interpreted as "including but not limited to"; "generally" means that those skilled in the art can solve the technical problem within a certain margin of error and basically achieve the technical effect.

[0113] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "inside", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the purpose of simplifying the description of this application and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0114] In this application, unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or merely surface contact. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0115] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0116] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An image acquisition module, characterized in that, Used for framing a target object; the image acquisition module includes a reflector, a lens assembly, and an image sensor, wherein the reflector, the lens assembly, and the image sensor are arranged sequentially along the optical axis of the lens assembly; wherein the reflecting surface of the reflector faces the lens assembly, and the reflecting surface is curved; The reflective surface is used to reflect light from the target object to the lens assembly, and the lens assembly is used to refract light emitted through the reflector to the image sensor.

2. The image acquisition module according to claim 1, characterized in that, The reflecting surface of the mirror is an even-order aspherical surface or a freeform surface.

3. The image acquisition module according to claim 1, characterized in that, The image acquisition module has an image downscaling ratio greater than or equal to 500; or / and The aspect ratio of the image acquisition module is less than or equal to 0.

1.

4. The image acquisition module according to claim 1, characterized in that, The center of the image sensor is offset from the optical axis of the lens assembly; the reflective surface is asymmetrically arranged with respect to the optical axis of the lens assembly.

5. The image acquisition module according to claim 4, characterized in that, The reflective surface includes an adjacent first sub-reflective surface and a second sub-reflective surface, which are located on opposite sides of the optical axis of the lens assembly, and the area of ​​the first sub-reflective surface is larger than the area of ​​the second sub-reflective surface. The first sub-reflective surface and the image sensor are located on opposite sides of the optical axis.

6. The image acquisition module according to any one of claims 1 to 5, characterized in that, The lens assembly includes a first lens group, an aperture stop, and a second lens group; the first lens group, the aperture stop, and the second lens group are arranged sequentially on the optical axis of the lens assembly along a specified direction, which is the direction in which the image sensor points to the reflector.

7. The image acquisition module according to claim 6, characterized in that, The first lens group adopts a telecentric optical path architecture.

8. The image acquisition module according to claim 6, characterized in that, The first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially in the specified direction; The first lens has positive optical power, the light-exiting surface of the first lens is concave, and the light-incident surface of the first lens is convex. The second lens has positive optical power, the light-exiting surface of the second lens is convex, and the light-incident surface of the second lens is concave. The third lens has negative optical power, the light-exiting surface of the third lens is concave, and the light-incident surface of the third lens is concave. The fourth lens has positive optical power, and the light-emitting surface of the fourth lens is convex, as is the light-receiving surface of the fourth lens.

9. The image acquisition module according to claim 8, characterized in that, The light-emitting surface and the light-receiving surface of the first lens are both even-order aspherical surfaces.

10. The image acquisition module according to claim 6, characterized in that, The optical power of the first lens group is greater than 0 and less than or equal to 0.25, and / or the optical power of the second lens group is greater than or equal to -1.2 and less than or equal to -0.

7.

11. The image acquisition module according to claim 6, characterized in that, The second lens group includes a fifth lens and a sixth lens arranged sequentially in the specified direction; The fifth lens has negative optical power, the light-exiting surface of the fifth lens is a plane, and the light-incident surface of the fifth lens is a concave surface; The sixth lens has negative optical power, and the light-emitting surface of the sixth lens is concave, as is the light-receiving surface of the sixth lens.

12. The image acquisition module according to claim 11, characterized in that, The light-emitting surface and the light-receiving surface of the sixth lens are both even-order aspherical surfaces.

13. A viewfinder device, characterized in that, include: case; as well as The image acquisition module as described in any one of claims 1 to 12, wherein the image acquisition module is disposed within the housing.

Images