Variable ND filter

Abstract

The utility model relates to a variable ND filter which comprises a base and a rotating mirror frame, a first CPL filter is installed on the base, a second CPL filter is installed on the rotating mirror frame, the rotating mirror frame is rotatably installed on the base, one of the base and the rotating mirror frame is provided with a limiting block, the other one is provided with an arc-shaped limiting groove, and the limiting block is in sliding fit with the limiting groove. The arc center angle of the limiting groove is smaller than 360 degrees, the rotation angle of the rotating mirror frame can be limited through cooperation of the limiting block and the limiting groove, the situation that the second CPL filter installed on the rotating mirror frame rotates to the angle where the second CPL filter and the first CPL filter generate cross dark fringes can be avoided, and then the problem that the variable ND filter generates the cross dark fringes in the using process is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of photographic and video equipment, in particular to a variable ND filter. Background Art

[0002] ND filter is also called neutral gray density filter or neutral gray filter, or gray filter for short. Its main function is to reduce the amount of light entering the camera, and to have the same, uniform, and only weakening effect on various wavelengths of light. When the picture is too bright or when shooting outdoors in strong sunlight, the light is too strong to shoot with a large aperture, or a longer exposure time is required under normal light conditions, and it may not be possible to shoot with the required slow shutter speed. In this case, the use of ND filter can reduce the amount of light passing through, avoid overexposure, and achieve large aperture shooting, thereby accurately reflecting the photographer's shooting intention.

[0003] The relative angles of the two polarizers of the existing variable ND filters on the market are all 360° fully adjustable. However, when the two polarizers are turned to a fixed angle, cross dark patterns will appear in the captured pictures, seriously affecting the shooting effect.

[0004] Therefore, there is an urgent need for a variable ND filter that can prevent cross dark patterns from appearing in the photographed pictures. Utility Model Content

[0005] In order to solve the above problems, the utility model provides a variable ND filter, which limits the rotation angle of a rotating frame installed, so that the second CPL filter on the rotating frame can only rotate within an angle that will not produce a cross pattern with the first CPL filter, thereby avoiding the problem of cross patterns during shooting.

[0006] To achieve the above purpose, the utility model provides the following solutions:

[0007] A variable ND filter comprises: a base and a rotating frame, wherein a first CPL filter is mounted on the base, a second CPL filter is mounted on the rotating frame, the rotating frame is rotatably mounted on the base, one of the base or the rotating frame is provided with a limit block, and the other is provided with an arc-shaped limit groove, the limit block is slidably matched with the limit groove, and the arc center angle of the limit groove is less than 360 degrees.

[0008] Preferably, the limiting groove is arranged on the base, and the limiting groove penetrates the base along the thickness direction of the base.

[0009] Preferably, the base is provided with a mounting groove for accommodating the rotating mirror frame, and the mounting groove is provided with an adjustment notch for a user to move the outer peripheral side wall of the rotating mirror frame.

[0010] Preferably, the rotating spectacle frame extends out of the mounting groove along the opening direction of the adjustment notch.

[0011] Preferably, a filter slot is provided on the base, and the first CPL filter is installed in the filter slot.

[0012] Preferably, a gear scale is provided at one end of the base close to the rotating spectacle frame, and a gear positioning post is provided on the rotating spectacle frame.

[0013] Preferably, a magnet is installed at one end of the base away from the rotating spectacle frame.

[0014] Preferably, a receiving groove is formed at one end of the base away from the rotating spectacle frame, and the magnet is installed in the receiving groove.

[0015] Preferably, a protruding handle is provided on the outer wall between the two ends of the base.

[0016] Preferably, both the first CPL filter and the second CPL filter adopt CPL double-sided coated filters.

[0017] The utility model has achieved the following technical effects compared with the prior art:

[0018] In this application, a limiting block is provided on one of the base or the rotating spectacle frame, and an arc-shaped limiting groove is formed on the other. The limiting block is in sliding fit with the limiting groove, and the central angle of the arc of the limiting groove is less than 360 degrees. Furthermore, the rotation angle of the rotating spectacle frame can be limited through the cooperation of the limiting block and the limiting groove, and it can be avoided that the second CPL filter installed on the rotating spectacle frame rotates to an angle that generates a cross-shaped dark pattern with the first CPL filter, thereby avoiding the problem of cross-shaped dark patterns appearing during the use of the variable ND filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] FIG Figure 1 is an exploded view of the variable ND filter disclosed in the embodiment of the present invention;

[0021] FIG Figure 2 is a top view of the base disclosed in the embodiment of the present invention;

[0022] FIG Figure 3 is a structural diagram of the rotating spectacle frame disclosed in the embodiment of the present invention;

[0023] Attached Figure 4 is Figure 3 the upward view schematic diagram;

[0024] Attached Figure 5 is the matching schematic diagram of the limit block and the limit groove disclosed in the embodiment of the present utility model;

[0025] Wherein, 1. Base; 2. Rotating spectacle frame; 3. First CPL filter; 4. Second CPL filter; 5. Limit block; 6. Limit groove; 7. Installation groove; 8. Adjustment notch; 9. Filter groove; 10. Magnet; 11. Accommodating groove; 12. Handle. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0027] The purpose of the present utility model is to provide a variable ND filter, which can prevent the second CPL filter from rotating to an angle that generates cross-shaped dark lines with the first CPL filter, avoiding the problem of cross-shaped dark lines appearing in the variable ND filter during use.

[0028] To make the above objects, features and advantages of the present utility model more obvious and understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0029] Refer to Figures 1-5The variable ND filter disclosed in the embodiment of the utility model comprises: a base 1 and a rotating frame 2, a first CPL filter 3 is mounted on the base 1, a second CPL filter 4 is mounted on the rotating frame 2, the rotating frame 2 is rotatably mounted on the base 1, and the relative angle between the first CPL filter 3 and the second CPL filter 4 can be adjusted by rotating the rotating frame 2, one of the base 1 or the rotating frame 2 is provided with a limiting block 5, and the other is provided with an arc-shaped limiting groove 6, the limiting block 5 is slidably matched with the limiting groove 6, and the limiting block 5 slides in the limiting groove 6 during the rotation of the rotating frame 2, and further The arc center angle of the limiting groove 6 is less than 360 degrees. When the limiting block 5 rotates to the end of the limiting groove 6 in a certain direction, it will not be able to continue to rotate in this direction due to the obstruction of the limiting groove 6, that is, the rotating frame 2 can only rotate within a specific rotatable space. Therefore, by reasonably designing the arc center angle of the limiting groove 6, the second CPL filter 4 can be prevented from rotating to an angle at which a cross pattern can be generated with the first CPL filter 3, thereby avoiding the problem of the variable ND filter generating a cross pattern during use, and achieving the technical effect of eliminating the appearance of a cross pattern without changing the original polarizer structure.

[0030] Those skilled in the art can understand that: the rotating lens frame 2 of the first CPL filter 3 and the second CPL filter 4 in the present application are coaxially arranged with the light-through hole of the base 1 .

[0031] As a preferred embodiment, the limit groove 6 is arranged on the base 1; more preferably, the limit groove 6 passes through the base 1 along the thickness direction of the base 1; the variable ND filter is relatively thin, and affected by the overall thickness of the variable ND filter, the groove depth of the limit groove 6 and the height of the limit block 5 are both subject to certain restrictions, which in turn affects the engagement depth between the limit groove 6 and the limit block 5. In this example, the limit groove 6 is arranged to pass through the base 1 along the thickness direction of the base 1 to form a bottomless through-type groove body, thereby effectively increasing the depth of the limit groove 6. At the same time, the height of the limit block 5 can also be increased accordingly, ensuring that the limit groove 6 and the limit block 5 have sufficient engagement depth, making it less likely for the limit block 5 to go out of the limit groove 6 during the rotation of the rotating mirror frame 2, making the matching relationship between the limit block 5 and the limit groove 6 more reliable.

[0032] Preferably, a mounting groove 7 for accommodating the rotating frame 2 is provided on the base 1. The setting of the mounting groove 7 enables the rotating frame 2 to be embedded in the base 1, thereby reducing the overall thickness of the variable ND filter; further, an adjustment notch 8 is provided on the mounting groove 7, and the user can touch the outer peripheral side wall of the rotating frame 2 through the adjustment notch 8 according to actual needs to drive the rotating frame 2 to rotate, thereby making the rotating frame 2 easier to adjust.

[0033] As a preferred manner, the rotating frame 2 extends out of the mounting groove 7 along the opening direction of the adjustment notch 8, which makes it easier for the user to move the rotating frame 2; preferably, stripes are provided on the outer peripheral side wall of the rotating frame 2 for increasing friction.

[0034] More preferably, a filter slot 9 is provided on the base 1, and the first CPL filter 3 is installed in the filter slot 9. The setting of the filter slot 9 enables the first CPL filter 3 to be embedded in the base 1, thereby reducing the overall thickness of the variable ND filter and allowing a certain gap to exist between the first CPL filter 3 and the camera when the variable ND filter is installed on the camera, thereby avoiding the contact between the first CPL filter 3 and the camera, which may cause the first CPL filter 3 or the camera to rub against each other and cause wear.

[0035] As a preferred embodiment, a gear scale is provided at one end of the base 1 close to the rotating frame 2, and a gear positioning column is provided on the rotating frame 2. When the gear positioning column is rotated to align with a certain gear scale, it indicates that the rotating frame 2 has rotated to the corresponding gear, thereby ensuring the accuracy of the gear of the rotating frame 2.

[0036] refer to Figures 1-5 In one embodiment, a magnet 10 is installed at one end of the base 1 away from the rotating frame 2, and the variable ND filter can be adsorbed on the camera through the magnet 10, and the use of the variable ND filter is more convenient by using magnetic attraction.

[0037] More preferably, a receiving groove 11 is provided at one end of the base 1 away from the rotating lens frame 2, and the magnet 10 is installed in the receiving groove 11. The setting of the receiving groove 11 enables the magnet 10 to be embedded in the interior of the base 1, thereby reducing the overall thickness of the variable ND filter; further, the groove depth of the receiving groove 11 is not greater than the thickness of the magnet 10, thereby avoiding the problem of insufficient attraction of the magnet 10 due to an increase in the gap between the magnet 10 and the camera, thereby ensuring the stability of the installation of the variable ND filter.

[0038] Furthermore, since the overall thickness of the variable ND filter is relatively thin, the present application provides an outwardly protruding handle 12 on the outer wall between the two ends of the base 1. More specifically, the handle 12 is arranged at an end away from the magnet 10 along the thickness direction of the base 1. The setting of the handle 12 provides the user with sufficient gripping position, so that the user can stably grip the variable ND filter to quickly complete the disassembly, assembly and removal of the variable ND filter.

[0039] Preferably, the first CPL filter 3 and the second CPL filter 4 are both CPL double-sided coated filters.

[0040] Adaptive changes made according to actual needs are all within the protection scope of this utility model.

[0041] It should be noted that for those skilled in the art, it is obvious that the present utility model is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or basic characteristics of the present utility model, the present utility model can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the utility model. Any reference signs in the claims should not be construed as limiting the claims involved.

Claims

1. A variable ND filter, characterized in that: include: A base (1) and a rotating mirror frame (2), wherein a first CPL filter (3) is mounted on the base (1), a second CPL filter (4) is mounted on the rotating mirror frame (2), and the rotating mirror frame (2) is rotatably mounted on the base (1), one of the base (1) or the rotating mirror frame (2) is provided with a limit block (5), and the other is provided with an arc-shaped limit groove (6), the limit block (5) is slidably matched with the limit groove (6), and the arc center angle of the limit groove (6) is less than 360 degrees.

2. The variable ND filter according to claim 1, characterized in that: The limiting groove (6) is arranged on the base (1), and the limiting groove (6) penetrates the base (1) along the thickness direction of the base (1).

3. The variable ND filter according to claim 1, characterized in that: The base (1) is provided with a mounting groove (7) for accommodating the rotating mirror frame (2), and the mounting groove (7) is provided with an adjustment notch (8) for a user to move the outer peripheral side wall of the rotating mirror frame (2).

4. The variable ND filter according to claim 3, characterized in that: The rotating mirror frame (2) extends out of the mounting groove (7) along the opening direction of the adjustment notch (8).

5. The variable ND filter according to claim 1, wherein: The base (1) is provided with a filter slot (9), and the first CPL filter (3) is installed in the filter slot (9).

6. The variable ND filter according to claim 1, wherein: A gear scale is provided at one end of the base (1) close to the rotating mirror frame (2), and a gear positioning column is provided on the rotating mirror frame (2).

7. The variable ND filter according to claim 1, wherein: A magnet (10) is mounted on one end of the base (1) away from the rotating mirror frame (2).

8. The variable ND filter according to claim 7, characterized in that: An end of the base (1) away from the rotating mirror frame (2) is provided with a receiving groove (11), and the magnet (10) is installed in the receiving groove (11).

9. The variable ND filter according to claim 7, wherein: An outwardly protruding handle (12) is provided on the outer wall between the two ends of the base (1).

10. The variable ND filter according to claim 1, wherein: The first CPL filter (3) and the second CPL filter (4) are both CPL double-sided coated filters.

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