CN220323686U

CN220323686U - Lens structure and image pickup apparatus

Info

Publication number: CN220323686U
Application number: CN202321851725.2U
Authority: CN
Inventors: 李昆; 龚俊强; 邱盛平; 肖明志; 吴恙; 刘德灿; 谭穗静; 卢耿光
Original assignee: Union Optech Co Ltd
Current assignee: Union Optech Co Ltd
Priority date: 2023-07-13
Filing date: 2023-07-13
Publication date: 2024-01-09
Anticipated expiration: 2033-07-13

Abstract

The utility model discloses a lens structure and image pickup equipment, the lens structure comprises a lens barrel, a lens assembly, a driving mechanism, a position detection device and a control device, wherein the lens barrel is arranged along a first direction in an extending way; the lens assembly comprises a lens group movably arranged along a first direction; the driving mechanism is used for driving the lens group to move along a first direction; the position detection device is used for detecting the position of the lens group in real time; the position detection device adopts closed-loop control, so that the position of the lens group can be detected in real time, the control device can adjust the position of the lens group in real time according to the displacement difference between the actual position and the target position of the lens group, the position is not limited by the physical precision and the abrasion precision of a product of a driving mechanism, and the lens group can accurately reach the target position required by zooming or focusing without being affected by the influence of the stop precision when the driving mechanism drives the lens group to move at a high speed, so that the problems of low rotating speed, slow lens adjusting speed and poor service life of the driving mechanism of the conventional lens structure are solved.

Description

Lens structure and image pickup apparatus

Technical Field

The present utility model relates to the field of focusing technologies, and in particular, to a lens structure and an image capturing apparatus.

Background

The current conventional security zoom lens generally adopts a stepping motor and a screw rod for transmission, so that zoom and focusing functions are realized; an optical coupler switch is adopted as an initial position sensor; the control system is an open loop system, and can only purely ensure the precision of the parts, so that when the step-out problem occurs in the process, the problem of picture blurring of the lens can occur; the basic motor can only be controlled with a relatively low rotational speed maintained. In addition, with the friction loss of a mechanical system, the product precision is reduced, and the problems of failure of the whole product application, blurring of pictures, frame loss and the like can be caused. Therefore, the lens in the prior art has the problems of low rotation speed of the driving motor, low adjustment speed of the lens and poor service life of the driving mechanism.

Disclosure of Invention

The utility model mainly aims to provide a lens structure and image pickup equipment, and aims to solve the problems of low rotation speed of a driving motor, low lens adjusting speed and poor service life of a driving mechanism in the existing lens structure.

In order to achieve the above object, the present utility model provides a lens structure, wherein the lens structure includes:

a lens barrel extending in a first direction;

a lens assembly including a lens group movably disposed along the first direction;

the driving mechanism is fixedly connected with the lens group and used for driving the lens group to move along the first direction;

the position detection device is used for detecting the position of the lens group in real time; the method comprises the steps of,

and the control device is electrically connected with the position detection device and the driving mechanism and is used for controlling the driving mechanism to work according to the position detection device so as to adjust the position of the lens group.

Optionally, the position detection means comprises a magnetic grating sensor or a grating sensor.

Optionally, the magnetic grating sensor comprises a magnetic head and a magnetic grating, the magnetic grating extends along the first direction, the magnetic head is movably arranged along the first direction, and the magnetic head is fixedly connected to the mirror group.

Optionally, the grating sensor includes a scale grating and an indication grating, the indication grating extends along the first direction, the indication grating is movably disposed along the first direction, and the indication grating is fixedly connected to the lens group.

Optionally, the driving mechanism includes:

a driving motor having an output rotation shaft extending in a first direction;

the screw rod extends along the first direction and is coaxially connected with the output rotating shaft; the method comprises the steps of,

the driving nut is sleeved on the periphery of the screw rod and fixedly connected with the lens group so as to drive the lens group to move along the first direction;

the control device is electrically connected with the driving motor and used for controlling the driving motor to work.

Optionally, the lens structure further comprises a limit switch and a trigger piece, wherein one of the limit switch and the trigger piece is fixedly arranged on the lens barrel, and the other is fixedly connected with the lens group;

the control device is electrically connected with the limit switch and used for controlling the driving motor to work according to the limit switch.

Optionally, the lens assembly includes a plurality of the lens groups arranged at intervals in the first direction;

the driving mechanism and the position detection device are provided with a plurality of driving mechanisms, each driving mechanism is used for driving one lens group to move, and each position detection device is used for detecting the position of the corresponding lens group;

the control device is electrically connected with the plurality of position detection devices and the plurality of driving mechanisms and is used for controlling the corresponding driving mechanism to work according to each position detection device.

Optionally, the control device includes a signal amplifier for amplifying a signal of the position information detected by the position detecting device.

The present utility model also provides an image pickup apparatus including a lens structure including:

a lens barrel extending in a first direction;

Optionally, the image capturing apparatus includes a monitoring apparatus.

In the technical scheme provided by the utility model, the position detection device adopts closed-loop control, can detect the position of the lens group (zoom group/compensation group) in real time in the stroke of the lens group moving along the first direction, and the control device adjusts the position of the lens group in real time according to the displacement difference between the actual position and the target position of the lens group, is not limited by the physical precision and the abrasion precision of a product of a driving mechanism, and is not influenced by the poor stop precision when the driving mechanism drives the lens group to move at a high speed, so that the lens group can accurately reach the target position required by zooming or focusing, and the problems of low rotation speed of a driving motor, low lens adjusting speed and poor service life of the driving mechanism of the conventional lens structure are solved.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic perspective view of an embodiment of a lens structure according to the present utility model;

FIG. 2 is a schematic perspective view of a part of the lens structure in FIG. 1;

FIG. 3 is a perspective view of the lens structure of FIG. 2 from another perspective;

fig. 4 is a perspective view of a portion of the lens structure of fig. 1 from another perspective.

Reference numerals illustrate:

the achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present utility model, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

In order to solve the above-mentioned problems, the present utility model provides a lens structure, and fig. 1 to fig. 4 are specific embodiments of the lens structure provided by the present utility model.

Referring to fig. 1 to 4, the lens structure 100 includes a lens barrel 1, a lens assembly 2, a driving mechanism 3, a position detecting device 4, and a control device 5, wherein the lens barrel 1 is disposed to extend along a first direction; the lens assembly 2 includes a lens group 21 movably disposed along the first direction; the driving mechanism 3 is fixedly connected with the lens group 21 and is used for driving the lens group 21 to move along the first direction; the position detecting device 4 is used for detecting the position of the lens group 21 in real time; the control device 5 is electrically connected to the position detecting device 4 and the driving mechanism 3, and is configured to control the driving mechanism 3 to work according to the position detecting device 4 so as to adjust the position of the lens group 21.

In the technical scheme provided by the utility model, the position detection device 4 adopts closed-loop control, so that the position of the lens group 21 (zoom group/compensation group) can be detected in real time in the stroke of the lens group 21 moving along the first direction, the position of the lens group 21 is regulated in real time by the control device 5 according to the displacement difference between the actual position of the lens group 21 and the target position, the limitation of the physical precision and the abrasion precision of the product of the driving mechanism 3 is avoided, and the influence of the poor stop precision is avoided when the driving mechanism 3 drives the lens group 21 to move at a high speed, so that the lens group 21 can accurately reach the target position required by zooming or focusing, and the problems of low rotation speed of the driving motor 31, slow lens regulation speed and poor service life of the driving mechanism 3 in the conventional lens structure 100 are solved.

Because the real-time feedback position information is based on the detection device, the driving mechanism 3 can perform high-speed driving control, the PID balance real-time position is used when the rotating speed is improved, the real-time position is not influenced by the step-out of the driving mechanism 3 (such as a screw rod 32 structure), even if the step-out problem exists, the detection device can timely detect the position deviation of the lens group 21, and the control device 5 can timely control the driving mechanism 3 to continuously work so as to adjust the position of the lens group 21, so that the zoom/focusing speed of the lens can be effectively improved.

It should be noted that, based on the above-mentioned closed-loop control, since the position detection device 4 can feed back the position information in real time, even if the driving mechanism 3 is mechanically worn, the variable magnification group/compensation group can reach the designated target position through the PID control algorithm under the condition that the system is not locked, so as to greatly improve the service life of the lens structure 100.

Specifically, referring to fig. 2, in the present embodiment, the position detecting device 4 includes a magnetic grating sensor 41 or a grating sensor.

The magnetic grating sensor 41 is composed of a magnetic grating, a magnetic head and a detection circuit, wherein the magnetic grating is formed by plating a layer of uniform magnetic film on a grating base made of non-magnetic conductive material and recording magnetic signal grating bars with equal interval and positive and negative staggered polarities, and the magnetic head comprises a dynamic magnetic head (a speed response magnetic head) and a static magnetic head (a magnetic flux response magnetic head). The dynamic head has an output winding that provides a signal output only when the head and the grating are in relative motion. The static magnetic head has two windings for exciting and outputting, and it can output signal when it is static relative to the magnetic grid. The static magnetic head is a multi-gap iron core with unequal effective cross sections, which is formed by stacking iron-nickel alloy sheets. The excitation winding acts as a magnetic switch. When it is supplied with ac power, the section of magnetic circuit with smaller core cross section is excited twice a week to generate magnetic saturation, so that the magnetic force line generated by the magnetic grid can not pass through the core. Only when the exciting current passes through zero twice a week, the iron core is not saturated, and the magnetic force lines of the magnetic grid can pass through the iron core. The output winding has the induced potential output at this time. The frequency is twice the frequency of the exciting current, and the amplitude of the output voltage is proportional to the magnetic flux entering the core, i.e. the position of the head relative to the grid. The magnetic head is made of multiple gaps in order to increase the output, and the output signal is the average value of signals obtained by multiple gaps, so that the output precision can be improved.

The grating sensor is a sensor that measures displacement using the principle of grating moire. A grating is an optical device consisting of a large number of equally wide, equally spaced parallel slits. A commonly used grating is made by engraving a large number of parallel scribe lines in a glass plate. The score is an opaque portion, and the smooth portion between the two scores can transmit light, which corresponds to a slit. The finished grating has thousands or even tens of thousands of notches within a width of 1 cm. Such a grating using diffraction of transmitted light is called a transmission grating. Moire fringes formed by the grating have optical amplification and average error effects, and can improve measurement accuracy. A typical grating sensor consists of four parts: ruler grating, indication grating, light path system and measuring system. As the scale grating moves relative to the index grating, it forms light and dark moire fringes that are distributed in a generally sinusoidal pattern. The fringes move at the relative speed of the grating and impinge directly on the photocell. A series of electrical pulses is obtained at its output. The digital signal output is generated by an amplifying, shaping, direction identifying and counting system, and directly displays the measured displacement.

Specifically, in one embodiment, the magnetic grating sensor 41 includes a magnetic head and a magnetic grating, the magnetic grating extends along the first direction, the magnetic head is movably disposed along the first direction, and the magnetic head is fixedly connected to the mirror group 21. Thus, the position of the magnetic head can indirectly reflect the position of the lens group 21, and the actual position of the lens group 21 can be accurately detected through the relative movement between the magnetic head and the magnetic grid.

Specifically, in another specific embodiment, the grating sensor includes a scale grating and an indication grating, the indication grating extends along the first direction, the indication grating is movably disposed along the first direction, and the indication grating is fixedly connected to the lens group 21. Therefore, the position of the indication grating can indirectly reflect the position of the lens group 21, and the actual position of the lens group 21 can be accurately detected through the relative movement between the indication grating and the scale grating.

Specifically, referring to fig. 3, in the present embodiment, the driving mechanism 3 includes a driving motor 31, a screw rod 32, and a driving nut 33, and the driving motor 31 has an output rotation shaft extending in a first direction; the screw rod 32 extends along the first direction and is coaxially connected to the output rotating shaft; the driving nut 33 is sleeved on the periphery of the screw rod 32, and the driving nut 33 is fixedly connected with the lens group 21 so as to drive the lens group 21 to move along the first direction; the control device 5 is electrically connected to the driving motor 31, and is used for controlling the driving motor 31 to work. Because the driving nut 33 drives the screw rod 32 to rotate by means of the driving motor 31, the rotation stroke of the screw rod 32 is converted into the movable stroke of the driving nut 33 along the first direction by means of threaded fit, so that the position of the lens group 21 in the first direction is adjusted, when the driving motor 31 works, the screw rod 32 rotates, the driving nut 33 drives the lens group 21 to move, and when the driving motor 31 is powered off, the screw rod 32 stops rotating, and the driving nut 33 stops moving. By controlling the drive motor 31 to be de-energized by the control device 5 when the mirror group 21 moves to the target position, the rotation is stopped, so that the mirror group 21 can stay to the target position.

Specifically, in this embodiment, the lens structure 100 further includes a limit switch 6 and a trigger piece, one of the limit switch 6 and the trigger piece is fixedly disposed on the lens barrel 1, and the other is fixedly connected to the lens group 21; the control device 5 is electrically connected to the limit switch 6, and is configured to control the driving motor 31 to work according to the limit switch 6.

It should be noted that, the interaction position of the limit switch 6 and the trigger piece is the position where the mirror group 21 returns to zero, so that when the trigger piece triggers the limit switch 6 to work, the limit switch 6 sends a power-off instruction, so that the driving motor 31 stops working, and the mirror group 21 is adjusted to an initial position. It may be understood that the limit switch 6 may be an infrared correlation control switch, and the trigger piece is a blocking piece, and when the blocking piece blocks infrared rays, it is indicated that the lens group 21 returns to its original position, and the limit switch 6 sends a control signal.

Further, in the zooming and focusing, a plurality of lens groups 21 are generally matched with each other, and each lens group 21 is located at a corresponding target position so as to be able to perform final clear imaging, so in this embodiment, the lens assembly 2 includes a plurality of lens groups 21 arranged at intervals in the first direction; the plurality of lens groups 21 may be set as a zoom group, a compensation group, etc., and in order to drive each lens group 21, the driving mechanism 3 and the position detecting device 4 are provided in plurality, each driving mechanism 3 is used for driving one lens group 21 to move, and each position detecting device 4 is used for detecting the position of a corresponding lens group 21; the control device 5 is electrically connected with the plurality of position detecting devices 4 and the plurality of driving mechanisms 3, and is used for controlling the corresponding driving mechanism 3 to work according to each position detecting device 4. So configured, each of the mirror groups 21 can be driven by one of the driving mechanisms 3, and each of the driving mechanisms 3 operates according to a corresponding one of the position detecting devices 4, so that each of the mirror groups 21 can be at a precise target position.

Specifically, the control device 5 includes a signal amplifier, where the signal amplifier is configured to amplify the signal of the position information detected by the position detecting device 4, and the signal amplifier uses an OPA operational amplifier circuit, so as to accurately amplify the detected signal, and facilitate providing accurate control information.

The present utility model also provides an image capturing apparatus, where the image capturing apparatus includes the above-mentioned lens structure 100, and since the image capturing apparatus includes the above-mentioned lens structure 100, the specific structure of the lens structure 100 refers to the above-mentioned embodiments, and since the lens structure 100 of the present image capturing apparatus adopts all the technical solutions of all the embodiments, at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments are provided, and will not be described in detail herein.

Specifically, the image capturing apparatus further includes a monitoring apparatus, and the monitoring apparatus adopts the lens structure 100 because the monitoring apparatus works with a higher magnification, and whether the image quality is clear or not, and the position detecting device 4 detects the position of the lens group 21 (zoom group/compensation group) in real time by adopting closed-loop control, so as to adjust the position of the lens group 21 in real time, so that the monitoring apparatus can realize clear imaging no matter what magnification the monitoring apparatus is under.

The focusing method of the lens structure 100 provided by the utility model comprises the following steps:

and S1, acquiring target position information.

The target position information is a set position of each of the lens groups 21 when the imaging of the optical system is clear, that is, when each of the lens groups 21 can accurately reach the target position, clear imaging is necessarily achieved.

Step S2, controlling the driving mechanism 3 to drive the lens group 21 to move from the initial position to the target position.

In the technical scheme provided by the utility model, a pulse signal is given according to the target position information, the driving mechanism 3 drives the lens group 21 to move according to the pulse signal, and when the lens group 21 moves towards the target position, the lens group 21 is positioned at the target position when the abrasion degree of the driving mechanism 3 is lower and the stopping precision and the physical precision are higher; when the driving mechanism 3 has low precision or is out of step, the mirror group 21 is located near the target position, and then the position detection device 4 detects and adjusts the mirror group in real time to reach the target position.

Step S3, controlling the position detecting device 4 to detect the position information of the lens group 21 in real time, and acquiring the actual position information of the lens group 21.

When the lens group 21 is driven by the driving mechanism 3 to move along the first direction, the position detecting device 4 can realize closed-loop control, detect the position of the lens group 21 in real time, and feed back the detected position information in real time.

And S4, comparing the actual position information with the target position information to obtain a displacement difference value.

In the optical system, when zooming and focusing are performed, according to focal lengths of the lenses in the lens groups 21, respective accurate target positions of the lens groups 21 can be determined when corresponding magnification is achieved, and clear imaging on an image plane can be finally achieved when the respective target positions are achieved, so that a difference value can be obtained by comparing the actual position information with the target position information, a displacement amount of the lens groups 21 can be obtained, and a numerical basis is provided for driving the lens groups 21 by the driving mechanism 3.

Step S5, according to the displacement difference, controlling the driving mechanism 3 to work so as to adjust the lens group 21 to the target position.

In the technical scheme provided by the utility model, the position detection device 4 adjusts the position of the lens group 21 in real time according to the displacement difference between the actual position and the target position of the lens group 21, is not limited by the physical precision and the abrasion precision of the product of the driving mechanism 3, and is not affected by the poor stopping precision when the driving mechanism 3 drives the lens group 21 to move at a high speed, so that the lens group 21 can accurately reach the target position required by zooming or focusing, and the problems of low rotating speed of the driving motor 31, slow lens adjusting speed and poor service life of the driving mechanism 3 in the conventional lens structure 100 are solved.

The foregoing description is only of the preferred embodiments of the present utility model and is not intended to limit the scope of the utility model, and all equivalent structural changes made by the description of the present utility model and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the utility model.

Claims

1. A lens structure, comprising:

a lens barrel extending in a first direction;

2. The lens structure of claim 1, wherein the position detection means comprises a magnetic grating sensor or a grating sensor.

3. The lens structure of claim 2, wherein the magnetic grating sensor comprises a magnetic head and a magnetic grating, the magnetic grating extending along the first direction, the magnetic head being movably disposed along the first direction, the magnetic head being fixedly connected to the mirror group.

4. The lens structure of claim 2, wherein the grating sensor comprises a scale grating and an indication grating, the indication grating extends along the first direction, the indication grating is movably arranged along the first direction, and the indication grating is fixedly connected to the lens group.

5. The lens structure of claim 1, wherein the driving mechanism comprises:

a driving motor having an output rotation shaft extending in a first direction;

6. The lens structure of claim 5, further comprising a limit switch and a trigger, wherein one of the limit switch and the trigger is fixedly arranged on the lens barrel, and the other is fixedly connected to the lens group;

7. The lens structure of claim 1, wherein the lens assembly includes a plurality of the lens groups arranged at intervals in the first direction;

8. A lens structure as claimed in claim 1, wherein the control means comprises a signal amplifier for amplifying a signal of the position information detected by the position detecting means.

9. An image pickup apparatus comprising the lens structure according to any one of claims 1 to 8.

10. The image capturing apparatus according to claim 9, wherein the image capturing apparatus includes a monitoring apparatus.