A rear focusing device and image acquisition equipment

Abstract

The present application relates to a kind of rear focusing device and image acquisition equipment.The rear focusing device includes guiding base with vertical guide slot, focusing knob, focusing cam with helical rotation slot, focusing support with guiding screw, wherein focusing cam is nested in the rotation through-hole of guiding base, the focusing support is nested in the inside of focusing cam, focusing knob is fixedly connected with focusing cam, drives focusing cam to rotate, so that guiding screw moves along helical rotation slot and vertical guide slot, further drives focusing support to move vertically.The rear focusing device and image acquisition equipment of the present application can realize manual fine adjustment of focal length from outside without disassembly through rear focusing knob and cam focusing, with low cost, simple operation and high precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of focal length adjustment, in particular to a rear focusing device and an image acquisition device. BACKGROUND

[0002] Image acquisition device refers to a device used to acquire image information. It uses a lens and an image sensor to convert images into electronic information, for example, a bar code reading device, which converts the bar code image on the target into electronic data and then translates it into corresponding data information by a special decoder. Because of its fast input speed, high reliability, large amount of information acquisition and flexible and practical points, bar code reading devices have been widely used in many fields such as commodity circulation, book management, postal management, banking system, etc. The focal length of early image acquisition devices is generally fixed, even if it can be manually adjusted before assembly, the focal length will be fixed and cannot be changed after assembly.

[0003] With the diversification of use scenarios, image acquisition devices need to have variable recognition range. The prior art image acquisition device usually uses liquid lens or driving motor to adjust the focal length of the lens. CN107257116A rear focusing adjustment mechanism and camera having the same proposes a rear focusing method, which drives the positioning guide mechanism to adjust the front and rear positions of the image sensor fixing plate by driving motor, thereby realizing the transfer of focal length. However, this scheme involves the cooperation between driving motor, nut, gear and other components, which is high in cost, complex in installation, difficult in subsequent maintenance and low in reliability. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to provide a rear focusing device and an image acquisition device in view of the above-mentioned deficiencies of the prior art.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is:

[0006] Technical scheme one

[0007] A rear focusing device, comprising:

[0008] A guide base, the guide base has a rotating through hole, and a vertical guide groove is arranged on one side wall of the rotating through hole.

[0009] A focusing cam, the focusing cam is in a hollow columnar shape, and the column side wall has a spiral rotating groove, the focusing cam is nested in the rotating through hole of the guide base and can rotate;

[0010] A focusing knob, the focusing knob is located below the guide base and is fixedly connected with the lower end of the focusing cam.

[0011] A focusing support, a part of which is nestedly installed in the inside of the focusing cam;

[0012] A guide screw, which is installed on the side wall of the lower end of the focusing support, sequentially passes through the helical rotation groove of the focusing cam and the guide groove of the guide base from inside to outside;

[0013] An image sensor carrier plate, which is fixed to the upper end of the focusing support.

[0014] The guide screw moves vertically up and down along the guide groove of the guide base.

[0015] The rear focusing device further comprises a bottom plate, the guide base is fixed to the bottom plate, and the focusing knob is located in the knob groove of the bottom plate.

[0016] The rear focusing device further comprises a focusing cam pressing ring, which is located at the upper end of the focusing cam, is fixed to the guide base, and limits the focusing cam in the rotation through hole of the guide base.

[0017] The rear focusing device further comprises a lens holder, which is provided with a lens, and is fixed to the guide base.

[0018] The lens holder is further provided with a spring positioning column, the spring is installed on the spring positioning column, and the other end of the spring contacts the upper surface of the image sensor carrier plate.

[0019] The focusing knob is provided with a rotation-stopping screw.

[0020] The bottom plate is provided with a focusing start symbol and a focusing end symbol, and the focusing knob is provided with a focusing position symbol.

[0021] The vertical distance between the upper end and the lower end of the guide groove is less than the vertical distance between the head end and the tail end of the helical rotation groove.

[0022] Technical solution two

[0023] An image acquisition device comprising the rear focusing device in the above technical solution one.

[0024] The rear focusing device and the image acquisition device have the following advantages: the cooperation between the guide base, the focusing cam, the focusing knob, the focusing support and the guide screw is adopted, the rotation displacement is converted into vertical displacement by the cam helix, manual focusing is realized, the rear focusing structure is adopted, the focal length adjustment of the device can be realized without removing the shell, the device is simple to assemble, convenient to operate, low in cost and high in reliability. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 exploded view of a rear focusing device according to an embodiment of the present application;

[0026] Figure 2 exploded view of an image acquisition device according to an embodiment of the present application;

[0027] Figure 3 combined view of a rear focusing device according to an embodiment of the present application;

[0028] Figure 4 combined view of an image acquisition device according to an embodiment of the present application;

[0029] Figure 5 cross-sectional view of an image acquisition device according to an embodiment of the present application;

[0030] Figure 6 bottom view of an image acquisition device according to an embodiment of the present application;

[0031] Figure 7 top view of an image acquisition device according to an embodiment of the present application.

[0032] The reference signs are: 1 - lens; 2 - lens holder; 3 - spring; 4 - screw; 5 - image sensor carrier plate; 6 - focusing holder; 7 - focusing cam pressing ring; 8 - focusing cam; 9 - guiding base; 10 - guiding screw; 11 - bottom plate; 12 - focusing knob; 13 - rotation-stopping screw. DETAILED DESCRIPTION

[0033] The present application will be described in detail below with reference to the drawings and specific embodiments.

[0034] As shown in Figures 1 to 7 a rear focusing device, comprising:

[0035] A guiding base 9, which has a rotating through-hole, and a vertical guiding groove is arranged on one side wall of the rotating through-hole. In this embodiment, the guiding base serves as the reference of the whole focusing device, and a plurality of fixing screw holes and fixing columns are arranged thereon, so as to facilitate the close fixing of other components with the guiding base 9.

[0036] A focusing cam 8, which is in the shape of a hollow column, and a helical rotating groove is arranged on the side wall of the column, and the focusing cam 8 is nested in the rotating through-hole of the guiding base 9, and can perform rotating movement. In this embodiment, the helical rotating groove starts from the middle part of the focusing cam 8, and extends upwards to the upper part of the focusing cam.

[0037] A focusing knob 12 is fixedly connected with the lower end of the focusing cam 8 below the guide base 9. In the embodiment, the focusing knob 12 is fixed by a screw 4, and has a recess, preferably rectangular, which can be used as a rotating force point to be inserted into a sheet-shaped object such as a flathead screwdriver for rotating focusing.

[0038] A focusing support 6 is partially nested in the inside of the focusing cam 8. In the embodiment, the lower part of the focusing support 6 is a columnar structure, and the upper part is a flat plate structure. The size of the lower part of the focusing support is slightly smaller than the size of the hollow part of the focusing cam.

[0039] A guide screw 10 is installed on the side wall of the lower end of the focusing support 6, and sequentially passes through the helical rotating groove of the focusing cam and the guide groove of the guide base from inside to outside. In the embodiment, the focusing support 6, the focusing cam 8 and the guide base 9 are sequentially nested during installation, and the rotating positions of the components are finely adjusted so that the screw hole on the focusing support 6, the helical rotating groove of the focusing cam 8 and the guide groove of the guide base are in a horizontal straight line. At this time, the guide screw is suspended on the focusing support 6.

[0040] The guide screw 10 moves vertically along the guide groove of the guide base 9. In the embodiment, when focusing is needed, the focusing knob 12 is rotated to drive the focusing cam to rotate. Because the guide screw 10 passes through the helical rotating groove, the movement track of the guide screw 10 is consistent with the helical rotating groove. However, because the guide screw 10 also passes through the guide groove of the guide base 9, the guide base 9 is in a fixed state, so that the rotating movement of the focusing cam 8 is converted into the vertical movement of the focusing support 6 connected with the guide screw 10.

[0041] An image sensor carrier plate 5 is fixed to the upper end of the focusing support 6. The image sensor carrier plate 5 is a PCB plate, and an image sensor is arranged on the image sensor carrier plate 5.

[0042] The rear focusing device further comprises a bottom plate 11, and the guide base is fixed to the bottom plate 11, and the focusing knob 12 is located in the knob groove of the bottom plate 11.

[0043] The rear focusing device further includes a focusing cam retaining ring 7, which is located at the upper end of the focusing cam 8 and fixed to the guide base 9, confining the focusing cam 8 within the rotating through hole of the guide base 9. In this embodiment, the focusing cam retaining ring 7 has a groove that matches the shape of the upper part of the focusing cam 8, and its size is slightly larger than the upper part of the focusing cam 8, so that when the focusing cam 8 is confined inside the guide base 9, its rotation is not affected. At this time, the focusing cam can only rotate and cannot move vertically up and down.

[0044] The rear focusing device also includes a lens bracket 2, on which a lens 1 is mounted, and the lens bracket 2 is fixed to the guide base 9. The lens 1 is aligned with the optical axis of the image sensor.

[0045] The lens holder 2 is also equipped with a spring positioning post, on which a spring 3 is mounted. The other end of the spring 3 contacts the upper surface of the image sensor carrier plate 5. The spring 3 can provide internal cushioning and also provides a certain amount of restoring force during focusing.

[0046] The focusing knob 12 is provided with a stop screw 13. In this embodiment, the lower surface of the base plate 11 has an annular groove that mates with the stop screw 13. When focusing is required, the stop screw 13 is loosened, allowing the focusing knob 12 to rotate. When focusing is complete, the stop screw 13 is tightened, so that the stop screw 13 is locked in place with the annular groove on the base plate 11, thus fixing the focusing knob 12 in place.

[0047] The base plate 11 is provided with a focusing start symbol and a focusing end symbol, and the focusing knob 12 is provided with a focusing position symbol. For example... Figure 5 As shown, the two dots around the base plate 11 are the starting and ending points for focusing, and the arrow on the focusing knob 12 indicates the current focal length. In this embodiment, the focusing knob can rotate 180 degrees.

[0048] The vertical distance between the upper and lower ends of the guide groove is less than the vertical distance between the beginning and end of the spiral rotating groove. The length of the guide groove is the adjustable focusing range of the equipment.

[0049] In another embodiment of the present invention, an image acquisition device includes the above-described post-focusing device.

[0050] This invention discloses a rear-focusing device and image acquisition equipment. By employing the cooperation of a guide base, a focusing cam, a focusing knob, a focusing bracket, and a guide screw, the cam helix converts rotational displacement into vertical displacement, achieving manual focusing. Furthermore, the rear-focusing structure allows for focal length adjustment without removing the outer casing, resulting in simple assembly, convenient operation, low cost, and high reliability.

[0051] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Therefore, all equivalent changes or modifications made to the methods described in accordance with the claims of this patent application are included within the scope of this patent application.

Claims

1. A post-focusing device, characterized in that, include: Guide base (9), the guide base (9) has a rotating through hole, and a vertical guide groove is provided on one side wall of the rotating through hole; The focusing cam (8) is a hollow column with a spiral rotating groove on the side wall. The focusing cam (8) is nested in the rotating through hole of the guide base (9) and can rotate. A focusing knob (12) is located below the guide base (9) and is fixedly connected to the lower end of the focusing cam (8); A focusing bracket (6), a portion of which is nested inside the focusing cam (8); Guide screw (10), the guide screw (10) is installed on the lower side wall of the focusing bracket (6), the guide screw (10) passes through the spiral rotating groove of the focusing cam and the guide groove of the guide base from the inside to the outside; Image sensor carrier plate (5), which is fixed to the upper end of the focusing bracket (6).

2. The post-focusing device according to claim 1, characterized in that: The guide screw (10) moves vertically up and down along the guide groove of the guide base (9).

3. The post-focusing device according to claim 1, characterized in that: The rear focusing device also includes a base plate (11), the guide base is fixed on the base plate (11), and the focusing knob (12) is located in the knob groove of the base plate (11).

4. The post-focusing device according to claim 1, characterized in that, The rear focusing device also includes a focusing cam pressure ring (7), which is located at the upper end of the focusing cam (8) and fixed on the guide base (9), thus confining the focusing cam (8) in the rotating through hole of the guide base (9).

5. A post-focusing device according to claim 1, characterized in that: The rear focusing device also includes a lens bracket (2), on which a lens (1) is disposed, and the lens bracket (2) is fixed to the guide base (9).

6. A post-focusing device according to claim 5, characterized in that: The lens bracket (2) is also provided with a spring positioning post, on which a spring (3) is installed, and the other end of the spring (3) contacts the upper surface of the image sensor carrier plate (5).

7. A rear focusing device according to claim 3, characterized in that: A non-rotating screw (13) is provided on the focusing knob (12).

8. A rear focusing device according to claim 3, characterized in that: The base plate (11) is provided with a focusing start symbol and a focusing end symbol, and the focusing knob (12) is provided with a focusing position symbol.

9. A post-focusing device according to claim 1, characterized in that: The vertical distance between the upper and lower ends of the guide groove is less than the vertical distance between the beginning and end of the spiral rotating groove.

10. An image acquisition device, comprising the post-focusing device according to any one of claims 1-8.

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