Dimmer

Abstract

The utility model provides a light reducing mirror. The light reducing mirror comprises a first polariscope and a second polariscope, the second polariscope and the first polariscope are coaxially arranged in the direction of the optical axis, and the second polariscope and the first polariscope are arranged in a relative rotation mode; and the fixed-value light reducing mirror and the first polariscope are coaxially arranged in the direction of the optical axis, and the fixed-value light reducing mirror is detachably arranged on the side, away from the first polariscope, of the second polariscope. The first polariscope and the second polariscope which rotate relative to each other are arranged to be matched with the detachable constant-value light reducing mirror, continuous adjustment of small light reducing amount is achieved through relative rotation of the first polariscope and the second polariscope under the condition that the constant-value light reducing mirror is not installed, and the light reducing amount of the light reducing amount is adjusted through relative rotation of the first polariscope and the second polariscope under the condition that the constant-value light reducing mirror is installed. Through relative rotation of the first polariscope and the second polariscope, continuous adjustment of high light reduction amount is achieved, and the probability of occurrence of cross curves is reduced.

Description

Technical Field

[0001] The present application belongs to the field of optical filters, and more specifically, to a neutral density filter. Background Art

[0002] Neutral density filter is an optical device used to reduce the intensity of light. The current mainstream neutral density filters are fixed value neutral density filter and adjustable neutral density filter. Fixed value neutral density filter: has a certain neutral density effect. Adjustable neutral density filter: by superimposing two polarizing filters and rotating one of the polarizing filters, an angular displacement is generated between the two polarizing lenses to obtain different light transmission amounts, thereby achieving a neutral density effect.

[0003] The degree of light reduction of the neutral density filter is usually measured by the ND value and the gear. For example, ND2 means that the light passing through the neutral density filter is 1 / 2 of the original light, and the corresponding gear is 1 gear. ND4 means that the light passing through the neutral density filter is 1 / 4 of the original light, and the corresponding gear is 2 gears. ND8 means that the light passing through the neutral density filter is 1 / 8 of the original light, and the corresponding gear is 3 gears. And so on. ND1024 means that the light passing through the neutral density filter is 1 / 1024 of the original light, and the corresponding gear is 10 gears. However, for the convenience of expression, ND1024 is generally marked as ND1000.

[0004] Existing adjustable neutral density filters can achieve good dimming adjustment at low gears with small rotation angles, but at high gears with large rotation angles, a cross-line phenomenon will appear, that is, a cross-shaped dark pattern will appear on the screen. Adjustable neutral density filters composed of different polarizers may have different gears at which the cross-lines appear. For example, an adjustable neutral density filter can achieve normal dimming adjustment at gears 1-5, but when it exceeds gear 6, the cross-line phenomenon will appear. For another example, an adjustable neutral density filter can achieve normal dimming adjustment at gears 1-8, but when it exceeds gear 8, the cross-line phenomenon will appear. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a neutral density filter to solve the technical problem of crosshairs appearing in adjustable neutral density filters in the prior art.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted in the present application is to provide a neutral density filter, comprising:

[0007] First polarizer;

[0008] A second polarizer is coaxially arranged with the first polarizer along the optical axis direction, and the second polarizer is arranged to rotate relative to the first polarizer;

[0009] The fixed-value dimming filter is coaxially arranged with the first polarizer along the optical axis direction, and the fixed-value dimming filter is detachably arranged on a side of the second polarizer away from the first polarizer.

[0010] Optionally, the neutral density filter includes an angle limiting structure for limiting a maximum rotation angle of the first polarizer and the second polarizer, wherein the maximum rotation angle is smaller than a minimum rotation angle when a cross line appears between the first polarizer and the second polarizer.

[0011] Optionally, the angle limiting structure includes a limiting boss and a limiting groove, one of the limiting boss and the limiting groove is arranged on the first polarizer, and the other is arranged on the second polarizer, and the limiting boss is fitted in the limiting groove.

[0012] Optionally, the ND value of the fixed-value neutral density filter is greater than or equal to a first ND value, and the first ND value is equal to a maximum ND value formed by the first polarizer and the second polarizer divided by a minimum ND value formed by the first polarizer and the second polarizer.

[0013] Optionally, the ND value of the fixed-value neutral density lens is less than or equal to a second ND value, and the second ND value is equal to twice the maximum ND value formed by the first polarizer and the second polarizer divided by the minimum ND value formed by the first polarizer and the second polarizer.

[0014] Optionally, the fixed-value neutral density filter is connected to the second polarizer by magnetic attraction.

[0015] Optionally, the second polarized glasses include a second frame and a second polarized lens disposed in the second frame;

[0016] The fixed value dimming glasses include a third frame and a fixed value dimming lens arranged in the third frame;

[0017] A positioning frame is circumferentially arranged on one side of the third lens frame facing the second lens frame, and the second lens frame is connected inside the positioning frame.

[0018] Optionally, a light-transmitting area of ​​the second polarizer is larger than a light-transmitting area of ​​the first polarizer.

[0019] Optionally, the first polarized glasses include a first frame and a first polarized lens disposed in the first frame;

[0020] The second polarized glasses include a second frame and a second polarized lens disposed in the second frame;

[0021] The first mirror frame comprises a first mirror frame body, the first mirror frame body is connected with an enlarged frame whose diameter matches that of the second mirror frame, and the second mirror frame is rotatably matched with the enlarged frame.

[0022] Optionally, an external thread is circumferentially arranged on a side of the first lens frame facing away from the second lens frame, and an internal thread is circumferentially arranged on a side of the third lens frame facing away from the second lens frame.

[0023] The beneficial effect of the present application is that, compared with the prior art, the present application is provided with a first polarizer and a second polarizer that rotate relatively to each other in cooperation with a detachable fixed-value dimming filter. When the fixed-value dimming filter is not installed, continuous adjustment of a smaller dimming amount is achieved through the relative rotation of the first polarizer and the second polarizer. When the fixed-value dimming filter is installed, continuous adjustment of a higher dimming amount is achieved through the relative rotation of the first polarizer and the second polarizer, thereby reducing the probability of the appearance of cross lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 A schematic diagram of a neutral density filter provided in an embodiment of the present application;

[0026] Figure 2 An exploded view of a neutral density filter provided in an embodiment of the present application;

[0027] Figure 3 A disassembled diagram of a fixed-value neutral density filter in the neutral density filter provided in an embodiment of the present application;

[0028] Figure 4 A disassembled diagram of a first polarizer and a second polarizer in the neutral density filter provided in an embodiment of the present application;

[0029] Figure 5 A cross-sectional view of a neutral density filter provided in an embodiment of the present application.

[0030] Among them, the reference numerals in the figure are:

[0031] The first polarizer 1, the first frame 11, the first frame body 111, the enlarged frame 112, the first polarizer lens 12, the limiting boss 13, the external thread 14, the second polarizer 2, the second frame 21, the second polarizer lens 22, the limiting groove 23, the fixed value dimming lens 3, the third frame 31, the fixed value dimming lens 32, the positioning frame 33, the internal thread 34, and the magnet 4. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0034] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. Low gear and high gear are relative concepts, not absolute concepts, that is, low gear is a lower gear relative to high gear, and high gear is a higher gear relative to low gear.

[0036] Please also read Figure 1 , Figure 2 and Figure 5 Now, the neutral density filter provided in the embodiment of the present application is described. The neutral density filter in the embodiment of the present application comprises:

[0037] The first polarizer 1;

[0038] The second polarizer 2 is coaxially arranged with the first polarizer 1 along the optical axis direction, and the second polarizer 2 and the first polarizer 1 are relatively rotatable.

[0039] The fixed-value neutral density filter 3 is coaxially arranged with the first polarizer 1 along the optical axis direction, and the fixed-value neutral density filter 3 is detachably arranged on a side of the second polarizer 2 away from the first polarizer 1 .

[0040] Polarizers are optical lenses that can selectively transmit or block polarized light in a specific direction. The first polarizer 1 and the second polarizer 2 are coaxial and relatively rotatable, and can be arranged in the same frame for rotation, or can be relatively rotatably connected. The fixed-value neutral density filter 3 and the second polarizer 2 are detachably connected, and the detachable connection can be a threaded connection, a snap-on connection, a screw, a magnetic connection, etc. When the first polarizer 1 and the second polarizer 2 are coaxial and relatively rotatable, the relative angle of the first polarizer lens 12 and the second polarizer lens 22 can be adjusted through the relative rotation of the first polarizer 1 and the second polarizer 2, and continuous light reduction adjustment can be achieved. However, when the light reduction amount is too large, a cross-line phenomenon will appear. In this embodiment, when the dimming requirement is within the range where no crosshairs will appear, the fixed-value dimming filter 3 is detachable and the fixed-value dimming filter 3 is not installed, and the required dimming amount is achieved by relying on the relative rotation of the first polarizer 1 and the second polarizer 2; when the dimming requirement is met by adjusting the angle of the first polarizer 1 and the second polarizer 2 and a crosshair phenomenon will appear, the fixed-value dimming filter 3 is installed. At this time, the overall dimming effect of the dimming filter is equal to the superposition of the dimming effect produced by the first polarizer 12 and the second polarizer 22 and the dimming effect of the fixed-value dimming filter 3. A greater degree of dimming can be achieved while ensuring that no crosshairs phenomenon appears. By adjusting the relative angle of the first polarizer 12 and the second polarizer 22, the overall dimming amount of the dimming filter can be adjusted.

[0041] For example, the relative rotation of the first polarized lens 12 and the second polarized lens 22 can achieve 1-10 levels of light reduction. However, when the light reduction level reaches 6 or more, a cross-line phenomenon will appear. Therefore, when the light reduction requirement is 1-5 levels, the fixed-value light reduction filter 3 is not installed, and the light reduction is directly achieved by the relative rotation of the first polarized lens 1 and the second polarized lens 2 to achieve the required light reduction amount. When the light reduction requirement is more than 6 levels, the fixed-value light reduction filter 3 is installed, and the light reduction amount is adjusted by the relative rotation of the first polarized lens 1 and the second polarized lens 2 to achieve the required light reduction amount. Figure 1-3 As shown, in order to facilitate the determination of the gear position, the gear position number can be marked on the neutral density filter based on the rotation angle. The first polarizer 1 is marked with a pointing arrow, the second polarizer 2 is marked with 1-5 gears, and the fixed value neutral density filter 3 is marked with 6-10 gears.

[0042] The neutral density filter of this embodiment is mainly used to be installed on the camera lens for shooting, and of course it can also be applied to other usage scenarios that require light reduction adjustment. The first polarizer 1, the second polarizer 2 and the fixed value neutral density filter 3 can be installed in the same frame, or different frames can be set respectively, or both of them can be set in the same frame. On some special equipment, they can also be directly installed on the housing of the equipment itself or a specially set bracket without setting a frame.

[0043] Since the fixed-value neutral density filter 3 is detachable, when used for camera shooting, the first lens frame 11 is connected to the lens so that one end of the connected fixed-value neutral density filter 3 faces outward, which facilitates the removal of the fixed-value neutral density filter 3. The shooting field angle is also called the shooting angle. In the process of shooting or taking pictures, the shooting field angles of all lenses are relatively large. The shorter the focal length of the lens used by the same camera, the larger the field angle of the lens will be, and the longer the focal length, the smaller the field angle of the lens will be. Therefore, due to the existence of the lens field angle, the thinner the overall thickness of the filter installed at the front end of the lens, the larger the field angle will be. If only the method of superimposing fixed-value neutral density filters is used for light reduction, it is usually necessary to superimpose multiple fixed-value neutral density filters to achieve the preset effect. If the fixed-value neutral density filters are superimposed too thick, the edge of the fixed-value neutral density filter will block the light within the shooting range, and the problem of dark corners at the four corners of the photograph will occur. Compared with the method of superimposing neutral density filters, this embodiment can effectively control the overall thickness of the neutral density filter, thereby reducing the dark corner problem caused by the too thick ND neutral density filter.

[0044] In general, compared with the existing adjustable neutral density filter, the neutral density filter of this embodiment can avoid the cross-line phenomenon whether in low or high gear, and compared with the method of superimposing neutral density filters, not only can the continuous adjustment of the light reduction amount be achieved whether in low or high gear, which can better meet the light reduction demand, but also the overall thickness of the neutral density filter can be thinner, reducing the vignetting problem caused by superimposing too thick neutral density filters. Therefore, the neutral density filter of this embodiment has obvious advantages for short focal length lenses such as 18mm.

[0045] In one embodiment of the present embodiment, the neutral density filter includes an angle limiting structure for limiting the maximum rotation angle of the first polarizer 1 and the second polarizer 2, and the maximum rotation angle is smaller than the minimum rotation angle at which a cross line appears between the first polarizer 1 and the second polarizer 2.

[0046] When the first polarizer 1 and the second polarizer 2 rotate at an angle that is too large, a cross-line phenomenon will appear. Therefore, in order to prevent the appearance of cross-lines due to an excessive rotation angle caused by improper operation during use, the present embodiment provides an angle limiting structure for limiting the maximum rotation angle of the first polarizer 1 and the second polarizer 2. The minimum rotation angle at which the first polarizer 1 and the second polarizer 2 appear cross-lines refers to an angle greater than which the cross-line phenomenon will appear, and an angle less than which the cross-line phenomenon will not appear. The polarized lenses used by the first polarizer 1 and the second polarizer 2 are different, and the minimum rotation angle at which the cross-lines appear may also be different for the first polarizer 1 and the second polarizer 2. Therefore, the specific maximum rotation angle limited by the angle limiting structure needs to be determined based on actual conditions. The rotation angle limiting structure can be a limit stopper relatively arranged on the first polarizer 1 and the second polarizer 2, or a lever and a lever hole of corresponding length.

[0047] The maximum rotation angle limited by the angle limiting structure is smaller than the minimum rotation angle at which the first polarizer and the second polarizer appear cross lines, thereby preventing the user from excessively adjusting the light reduction amount of the first polarizer 1 and the second polarizer 2 to cause the cross line phenomenon.

[0048] See also Figure 4 In one embodiment of the present application, the angle limiting structure includes a limiting boss 13 and a limiting groove 23, one of which is disposed on the first polarizer 1, and the other is disposed on the second polarizer 2, and the limiting boss 13 fits in the limiting groove 23. The limiting boss 13 and the limiting groove 23 are disposed on the first polarizer 1 and the second polarizer 2, respectively. If the limiting boss 13 is located on the first polarizer 1, the limiting groove 23 is located on the second polarizer 2. Conversely, if the limiting boss 13 is located on the second polarizer 2, the limiting groove 23 is located on the first polarizer 1.

[0049] When the limiting boss 13 slides to the end of the limiting groove 23, a limiting effect can be generated to limit the continued relative rotation, that is, the length of the limiting groove 23 can limit the relative rotation angle of the first polarizer 1 and the second polarizer 2. This structure is not only simple in structure, but also has high stability. The limiting boss 13 and the limiting groove 23 are hidden between the first polarizer 1 and the second polarizer 2, and the appearance is more beautiful.

[0050] The ND value of the fixed-value neutral density lens 32 added to the first polarizer 1 and the second polarizer 2 directly affects the high-grade neutral density effect.

[0051] In one embodiment of the present application, the ND value of the fixed value neutral density filter 3 is greater than or equal to the first ND value, and the first ND value is equal to the maximum ND value formed by the first polarizer 1 and the second polarizer 2 divided by the minimum ND value formed by the first polarizer 1 and the second polarizer 2. The adjustable range of the first polarizer 1 and the second polarizer 2 is from the minimum ND value to the maximum ND value. The ND value after the neutral density filter is superimposed is equal to the product of the ND values ​​of the original neutral density filters. Therefore, if the ND value of the fixed value neutral density filter 3 is equal to the first ND value, after the fixed value neutral density filter 3 is installed, when the first polarizer 1 and the second polarizer 2 are adjusted to the minimum ND value, the total ND value of the neutral density filter is equal to the maximum ND value when the fixed value neutral density filter 3 is not installed. At this time, by adjusting the rotation angle of the first polarizer 1 and the second polarizer 2, a continuous increase can be achieved on the basis of the maximum ND value when the fixed value neutral density filter 3 is not installed, and the maximum can be increased to the product of the first ND value and the maximum ND value when the fixed value neutral density filter 3 is not installed. That is to say, when the ND value of the fixed-value neutral density filter 3 is equal to the first ND value, the neutral density filter of this embodiment can achieve continuous adjustment within the entire adjustable range. For example, in order to avoid the appearance of crosshairs, the adjustable range of the first polarizer 1 and the second polarizer 2 is limited to ND2 to ND32, and the first ND value is ND16. When the specification of the fixed-value neutral density filter 3 is installed, the relative angle of the first polarizer 1 and the second polarizer 2 can be adjusted between ND32 and ND512 to achieve continuous adjustment of the light reduction amount. Adding the adjustment range of ND2 to ND32 when the fixed-value neutral density filter 3 is not installed, the neutral density filter as a whole can be adjusted between ND2 and ND512. For another example, the adjustable range of the first polarizer 1 and the second polarizer 2 is limited to ND2 to ND64, and the first ND value is ND32. The fixed-value neutral density filter 3 of this specification can expand the adjustable range of light reduction to ND2 to ND2048. However, in actual marking, it is usually more often marked as ND2 to ND2000.

[0052] Of course, the ND value of the fixed-value neutral density filter 3 may also be greater than or less than the first ND value. When the ND value of the fixed-value neutral density filter 3 is less than the first ND value, the dimming adjustment ranges of the fixed-value neutral density filter 3 and the fixed-value neutral density filter 3 not being installed will overlap, and the overall maximum dimming amount of the neutral density filter will be affected; when the ND value of the fixed-value neutral density filter 3 is greater than the first ND value, there will be a gap in the dimming adjustment ranges of the fixed-value neutral density filter 3 and the fixed-value neutral density filter 3 not being installed, but it is beneficial to improve the overall maximum dimming amount of the neutral density filter, and it can be applied when the accuracy of the dimming amount is not strictly required.

[0053] However, the interval between the dimming adjustment ranges of the fixed-value dimming filter 3 and the fixed-value dimming filter 3 is preferably not more than 1 level. Therefore, in a preferred embodiment of the present application, the ND value of the fixed-value dimming filter 32 is less than or equal to the second ND value, and the second ND value is equal to 2 times the maximum ND value formed by the first polarizer 1 and the second polarizer 2 divided by the minimum ND value formed by the first polarizer 1 and the second polarizer 2. The ND values ​​of the dimming levels before and after 1 level are in a 2-fold relationship, for example, the ND value of level 1 is 2, the ND value of level 2 is 4, the ND value of level 3 is 8, and so on. When the ND value of the fixed value ND lens 32 is equal to the second ND value, after the fixed value ND lens 3 is installed and the first polarizer 1 and the second polarizer 2 are rotated to the minimum ND value, the ND value of the ND lens as a whole is exactly twice the maximum ND value formed by the first polarizer 1 and the second polarizer 2, that is, the interval between the dimming adjustment range when the fixed value ND lens 3 is installed and when the fixed value ND lens 3 is not installed is exactly 1 level, that is, the ND value of the fixed value ND lens 32 is less than or equal to the second ND value, which can ensure that the interval between the dimming adjustment range when the fixed value ND lens 3 is installed and when the fixed value ND lens 3 is not installed does not exceed 1 level. For example, if the adjustable range of the first polarizer 1 and the second polarizer 2 is limited to ND2 to ND32, the second ND value is ND32, and after the fixed value ND lens 3 with a specification of ND32 is installed, the overall dimming adjustment range is ND64 to ND1024, where ND1024 is usually marked as ND1000. The difference between ND64 and ND32 is exactly 1 stop. The specification of the fixed-value neutral density filter 3 can be less than or equal to ND32. There will be no situation where the interval between the dimming adjustment range with and without the fixed-value neutral density filter 3 installed exceeds 1 stop.

[0054] In one embodiment of the present application, the fixed-value neutral density filter 3 is connected to the second polarizer 2 by magnetic attraction. Magnetic attraction connection refers to a connection method achieved by adsorption of a magnet 4, and the magnetic attraction connection can be an adsorption connection between a magnet 4 and a ferromagnetic material, or an adsorption connection between magnets 4, that is, the second polarizer 2 and the fixed-value neutral density filter 3 can be provided with a magnet 4 and a ferromagnetic material, or with magnets 4, respectively. However, when magnets 4 are provided on both the second polarizer 2 and the fixed-value neutral density filter 3, it is necessary to ensure that the magnets 4 of the two mirrors are in an attracting orientation.

[0055] The magnet 4 and the ferromagnetic material can be in the form of an annular plate structure, a multi-section arc plate structure, a plurality of block structures, etc. Figure 3 In the illustrated embodiment, a plurality of receiving holes are evenly provided along the circumferential direction of the second frame 21 of the second polarizer 2 and the third frame 31 of the fixed-value neutral density filter 3, and the magnet 4 and the ferromagnetic material are installed in the receiving holes by interference fit or gluing, thereby ensuring that a uniform and stable adsorption force is provided in the circumferential direction without causing too much influence on the original structure of the frame.

[0056] The magnetic connection is convenient for disassembly and installation, and the required overall thickness is small, which can better control the thickness of the entire neutral density filter to better avoid vignetting problems.

[0057] like Figure 3 As shown, in one embodiment of the present application, the second polarizer 2 includes a second frame 21 and a second polarizer lens 22 disposed in the second frame 21;

[0058] The fixed value dimming lens 3 comprises a third lens frame 31 and a fixed value dimming lens 32 arranged in the third lens frame 31;

[0059] A positioning frame 33 is circumferentially provided on one side of the third mirror frame 31 facing the second mirror frame 21 , and the second mirror frame 21 is connected inside the positioning frame 33 .

[0060] Since the fixed-value neutral density filter 3 is often disassembled and installed, it is necessary to ensure the accuracy of its installation position, especially when a quick connection method such as magnetic connection is adopted, it is even more necessary to achieve its positioning in a simple and quick manner. In this embodiment, when installing the fixed-value neutral density filter 3, the positioning frame 33 of the third frame 31 is put on the second frame 21, and the third frame 31 and the second frame 21 can be accurately positioned. This positioning method is most consistent with the magnetic connection method. When the positioning frame 33 of the third frame 31 is put on the second frame 21, the accurate installation of the fixed-value neutral density filter 3 is completed under the action of magnetic attraction.

[0061] like Figure 5 As shown, in one embodiment of the present application, the light passing area of ​​the second polarizer 2 is greater than the light passing area of ​​the first polarizer 1. The light passing areas of the second polarizer 2 and the first polarizer 1 are usually determined by the size of the frame and the lens. Usually, the larger the light passing area, the larger the lens and the larger the inner diameter of the frame, so that the area through which light can pass is larger. For example, Figure 5 In the illustrated embodiment, the first polarizer 1 may be a lens of M77 specification with a diameter Φ of 74 mm, and the second polarizer 2 may be a lens of M82 specification with a diameter Φ of 79 mm, and its light transmission area is larger than that of the first polarizer 1 .

[0062] In this embodiment, the light transmission area of ​​the second polarizer 2 is greater than that of the first polarizer 1, and the light entering the first polarizer 1 from the second polarizer 2 can be increased on all sides, thereby further avoiding the problem of dark corners around the superimposed filter.

[0063] like Figure 4 As shown, in one embodiment of the present application, the first polarizer 1 includes a first frame 11 and a first polarizer lens 12 disposed in the first frame 11;

[0064] The second polarizer 2 includes a second frame 21 and a second polarizer lens 22 disposed in the second frame 21;

[0065] The first lens frame 11 comprises a first lens frame body 111 , to which an enlarged frame 112 having a diameter matching that of the second lens frame is connected, and the second lens frame 21 is rotatably matched with the enlarged frame 112 .

[0066] Since the light-transmitting area of ​​the second polarizer 2 is larger than that of the first polarizer 1, it is difficult for the first frame body 111 to directly achieve rotational cooperation with the second frame 21. In this embodiment, an enlarged frame 112 with a diameter that is compatible with the second frame 21 is increased on the basis of the first frame body 111, and the enlarged frame 112 is used to achieve rotational cooperation with the second frame 21. Therefore, when the light-transmitting area of ​​the second polarizer 2 is larger than that of the first polarizer 1, good rotational cooperation between the first frame 11 and the second frame 21 is guaranteed.

[0067] like Figure 5 As shown, in one embodiment of the present application, an external thread 14 is circumferentially provided on the side of the first polarizer 1 facing away from the second polarizer 2, and an internal thread 34 is circumferentially provided on the side of the fixed-value neutral density filter 3 facing away from the second polarizer 2. As mentioned above, the installation of the neutral density filter is to connect the first frame 11 with the lens so that one end of the connected fixed-value neutral density filter 3 faces outward. In this embodiment, the external thread 14 on the first frame 11 is used to connect with the lens, and the internal thread 34 on the third frame 31 can be used to install a lens cover to protect the lens. In addition, the connection structure at both ends of the neutral density filter can also refer to existing filter installation methods, such as snap-on, buckle, etc.

[0068] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A neutral density filter, characterized in that: include: A first polarizing filter (1); A second polarizer (2) is coaxially arranged with the first polarizer (1) along the optical axis direction, and the second polarizer (2) and the first polarizer (1) are arranged to rotate relative to each other; A fixed-value dimming filter (3) is coaxially arranged with the first polarizer (1) along the optical axis direction, and the fixed-value dimming filter (3) is detachably arranged on a side of the second polarizer (2) facing away from the first polarizer (1).

2. The neutral density filter according to claim 1, wherein: An angle limiting structure is included, which is used to limit the maximum rotation angle of the first polarizer (1) and the second polarizer (2), wherein the maximum rotation angle is smaller than the minimum rotation angle when a cross line appears between the first polarizer (1) and the second polarizer (2).

3. The neutral density filter according to claim 2, wherein: The angle limiting structure comprises a limiting boss (13) and a limiting groove (23), one of the limiting boss (13) and the limiting groove (23) being arranged on the first polarizer (1), and the other being arranged on the second polarizer (2), and the limiting boss (13) being fitted into the limiting groove (23).

4. The neutral density filter according to claim 2, wherein: The ND value of the fixed-value neutral density filter (3) is greater than or equal to a first ND value, and the first ND value is equal to the maximum ND value formed by the first polarizer (1) and the second polarizer (2) divided by the minimum ND value formed by the first polarizer (1) and the second polarizer (2).

5. The neutral density filter according to claim 2, 3 or 4, characterized in that: The ND value of the fixed-value neutral density filter (3) is less than or equal to a second ND value, and the second ND value is equal to twice the maximum ND value formed by the first polarizer (1) and the second polarizer (2) divided by the minimum ND value formed by the first polarizer (1) and the second polarizer (2).

6. The neutral density filter according to claim 1, wherein: The fixed-value neutral density filter (3) is connected to the second polarizing filter (2) by magnetic attraction.

7. The neutral density filter according to claim 1, 2, 3 or 6, characterized in that: The second polarizing lens (2) comprises a second lens frame (21) and a second polarizing lens (22) arranged in the second lens frame (21); The fixed-value dimming lens (3) comprises a third lens frame (31) and a fixed-value dimming lens (32) arranged in the third lens frame (31); A positioning frame (33) is provided along the circumferential direction on one side of the third mirror frame (31) facing the second mirror frame (21), and the second mirror frame (21) is connected inside the positioning frame (33).

8. The neutral density filter according to claim 1, 2, 3 or 6, characterized in that: The light transmission area of ​​the second polarizer (2) is greater than the light transmission area of ​​the first polarizer (1).

9. The neutral density filter according to claim 8, wherein: The first polarizing glasses (1) comprise a first frame (11) and a first polarizing lens (12) arranged in the first frame (11); The second polarizing lens (2) comprises a second lens frame (21) and a second polarizing lens (22) arranged in the second lens frame (21); The first mirror frame (11) comprises a first mirror frame body (111), the first mirror frame body (111) is connected to an enlarged frame (112) whose diameter matches that of the second mirror frame (21), and the second mirror frame (21) is rotatably matched with the enlarged frame (112).

10. The neutral density filter according to claim 1, 2, 3 or 6, characterized in that: An external thread (14) is circumferentially arranged on a side of the first polarizer (1) facing away from the second polarizer (2), and an internal thread (34) is circumferentially arranged on a side of the fixed-value dimming filter (3) facing away from the second polarizer (2).

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