CN214540197U

CN214540197U - Automatic focusing device

Info

Publication number: CN214540197U
Application number: CN202022035188.7U
Authority: CN
Inventors: 唐云飞; 李屹
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2021-10-29
Anticipated expiration: 2030-09-16

Abstract

The application discloses an automatic focusing device, which comprises a lens, a lens barrel, a controller and a driving device, wherein the lens barrel is provided with a resistor strip, the lens is provided with a contact point contacted with the resistor strip, at least one end of the resistor strip is connected with the controller, and the contact point is connected with the controller; the controller is used for detecting contact voltage on the contact, obtaining the current angle of the lens cone according to the contact voltage, and obtaining the angle difference required by the rotation of the lens cone according to the pre-obtained imaging angle and the current angle; the driving device is connected with the controller and is used for driving the lens barrel to rotate so as to reduce the angle difference; the contact voltage detected by the controller varies following the rotation of the lens barrel. By means of the mode, automatic focusing can be achieved, and cost is reduced.

Description

Automatic focusing device

Technical Field

The application relates to the technical field of projection, in particular to an automatic focusing device.

Background

Most of projection focusing can be realized by rotating a lens barrel at present, but the rapid automatic focusing realized by measuring the projection distance needs to know the rotating angle of the lens barrel, and the lens is out of focus after the temperature of the lens rises, and the lens barrel needs to be rotated for adjustment again; in addition, still can utilize distance sensor to survey the projection distance, and after knowing the angular position of current camera lens, throw out the direction and the angle that need rotate this moment according to the camera lens specification of focusing, reuse motor drives the camera lens and accomplishes auto focus fast, but current camera lens rotation angle is mostly realized through motor regulation step number, need through sensor induction motor initial position, and it is difficult to eliminate to have structure fit clearance, the motor has idle stroke and the inaccurate problem of rotation angle calculation, lead to the auto focus speed slow, experience is relatively poor, and the cost of external installation angle sensor is higher, and need increase new mechanism and cooperate, introduce new error easily.

SUMMERY OF THE UTILITY MODEL

The application provides an automatic focusing device, which can realize automatic focusing and reduce cost.

In order to solve the technical problem, the technical scheme adopted by the application is as follows: the automatic focusing device comprises a lens, a lens barrel, a controller and a driving device, wherein a resistor strip is arranged on the lens barrel, a contact point which is contacted with the resistor strip is arranged on the lens, at least one end of the resistor strip is connected with the controller, and the contact point is connected with the controller; the controller is used for detecting contact voltage on the contact, obtaining the current angle of the lens cone according to the contact voltage, and obtaining the angle difference required by the rotation of the lens cone according to the pre-obtained imaging angle and the current angle; the driving device is connected with the controller and is used for driving the lens barrel to rotate so as to reduce the angle difference; the contact voltage detected by the controller varies following the rotation of the lens barrel.

Through the scheme, the beneficial effects of the application are that: the current angle of the lens barrel is detected through the resistor strip on the lens barrel and the contact point on the lens, the contact point and the resistor strip are mutually contacted, when the lens barrel rotates, the resistance strip moves along with the lens barrel, so that the contact position of the contact and the resistance strip is changed, the controller can detect the voltage at the contact, and calculates a current angle corresponding to the current contact voltage using a mapping relationship between the contact voltage and the current angle, then the imaging angle and the current angle are utilized to calculate the angle difference of the lens cone which needs to be rotated, the lens cone rotates under the action of the driving device, the angle difference is reduced, and the picture shot by the lens is clear, because the contact voltage changes along with the rotation of the lens cone, the automatic focusing and clear imaging can be realized, and simple structure need not newly to increase the mechanism and come the cooperation contact or resistance strip, can not introduce new error, can save the cost.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:

FIG. 1 is a schematic structural diagram of an embodiment of an auto-focusing apparatus provided in the present application;

FIG. 2 is a schematic diagram of contacts and resistor bars in the embodiment shown in FIG. 1;

FIG. 3 is a schematic structural diagram of another embodiment of an auto-focusing apparatus provided in the present application;

fig. 4 is a schematic diagram of the connections of the analog-to-digital converter, power supply, resistor strip and temperature sensor in the embodiment shown in fig. 3.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of an auto-focusing apparatus provided in the present application, where the auto-focusing apparatus includes a lens 11, a lens barrel 12, a controller 13, and a driving device 14.

The lens 11 is of a retractable structure, the lens 11 is provided with a contact 111, the contact 111 may be a conductor, and the contact 111 may be connected with the controller 13 through a wire.

The lens barrel 12 is connected with the lens 11, the lens barrel 12 is provided with a resistor strip 121 contacted with the contact 111, at least one end of the resistor strip 121 is connected with the controller 13, and the contact 111 is connected with the controller 13; specifically, a chute (not shown in the figure) is arranged on the lens barrel 12, the resistor strip 121 is attached to the side surface of the chute, the contact 111 protruding from the lens 11 is embedded into the chute and abuts against the resistor strip 121, the resistance value of the resistor strip 121 changes uniformly along with the length, the resistor strip can be a carbon film or a resistance wire, the two opposite ends of the resistor strip 121 are respectively connected with a conducting wire, the resistor strip 121 moves along with the lens barrel 12 when the lens barrel 12 rotates, and the contact position of the contact 111 and the resistor strip 121 changes along with the rotation; the controller 13 is used for detecting the contact voltage on the contact 111, and the contact voltage detected by the controller 13 changes along with the rotation of the lens barrel 12; for example, as shown in fig. 2, at time t1, the contact 111 contacts with a position a of the resistor strip 121, the resistance value corresponding to the position a is R1, and the contact voltage detected by the controller 13 is denoted as U1; as the lens barrel 12 rotates, at time t2, the contact 111 contacts with the position B of the resistive strip 121, the resistance value corresponding to the position B is R2, and the contact voltage detected by the controller 13 is denoted as U2.

The controller 13 is further configured to obtain a current angle of the lens barrel 12 according to the contact voltage, and obtain an angle difference that the lens barrel 12 needs to rotate according to a pre-obtained imaging angle and the current angle of the lens barrel 12; specifically, the angle difference is an angle for making imaging clear, a mapping relationship exists between the current angle of the lens barrel 12 and the contact voltage, and the controller 13 can calculate the current angle according to the current contact voltage and the mapping relationship between the current angle and the contact voltage; and the current angle of the lens barrel 12 has a mapping relation with the imaging angle and the angle difference, the angle of the lens barrel 12 which needs to be rotated at present can be calculated according to the mapping relation, the current angle and the angle difference, and the imaging of the lens 11 can be clear after the lens barrel 12 is driven to rotate.

A driving device 14 may be connected to the lens barrel 12 for driving the lens barrel 12 to rotate so that the angular difference is reduced; specifically, the driving device 14 is connected to the controller 13, and can receive the angle difference sent by the controller 13 and drive the lens barrel 12 to rotate, so that the lens barrel 12 rotates to drive the lens 11 to move back and forth, and auto-focusing and clear imaging are achieved.

In other embodiments, the angle difference may also be the angular position of the lens barrel 12, i.e. the final angle of the lens barrel 12, and the implementation principle is similar to that of the above embodiments, and is not described herein again.

The embodiment provides an automatic focusing device, a contact 111 and a resistor 121 are respectively arranged on a lens 11 and a lens barrel 12, and the contact 111 and the resistor 121 are in contact with each other, when the lens barrel 12 rotates, the resistor 121 moves along with the lens barrel 12, so that the contact position of the contact 111 and the resistor 121 changes, namely the contact voltage changes, a controller 13 can detect the contact voltage, the current angle of the lens barrel 12 is calculated by using the contact voltage and the mapping relation between the contact voltage and the current angle, then the angle required for the rotation of the lens barrel 12 is calculated by using the imaging angle and the current angle, the lens barrel 12 rotates under the action of a driving device 14, so that the picture shot by the lens 11 is clear, and the contact voltage changes along with the rotation of the lens barrel 12, so that automatic focusing and clear imaging can be realized.

Referring to fig. 3, fig. 3 is a schematic structural diagram of another embodiment of an auto-focusing apparatus provided in the present application, in which a contact is an elastic sheet 222.

The elastic sheet 222 can be abutted against the lens barrel 22 to prevent the occurrence of a gap to generate a forward and reverse idle stroke error, and ensure an accurate mapping relation between the contact voltage and the position of the contact 211; specifically, the elastic sheet 222 is disposed on the lens barrel 22, the elastic sheet 222 contacts the resistor strip 221 moving along with focusing, and the contact 211 can be tightly fitted with the resistor strip 221 in the inclined groove through the elastic sheet 222; for example, as shown in fig. 4, the resistance value between the contact 211 and one end (B end) of the resistor strip 221 is denoted by R1, the contact voltage is denoted by U, the angle of the lens barrel 22 is denoted by α, the resistance value R1 can be continuously changed, the contact voltage U can be continuously changed, and the angle α and the contact voltage U have a linear relationship, that is, α ═ AU, and a is a constant.

The controller 23 includes a detection circuit 231 and a processor 232 connected to each other, and the detection circuit 231 is connected to the resistor strip 221, and is configured to detect a contact voltage and perform an analog-to-digital conversion process on the contact voltage to obtain a digital voltage.

In a specific embodiment, the detection circuit 231 includes an analog-to-digital converter 2311 and a power supply 2312 connected to each other, the analog-to-digital converter 2311 is used for converting the contact voltage into a first digital voltage and feeding the first digital voltage back to the processor 232; specifically, the analog-to-digital converter 2311 may collect the contact voltage, and the angle of the lens barrel 22, i.e., the current angle, may be calculated using the functional relationship between the angle of the lens barrel 22 and the contact voltage.

As shown in fig. 4, the analog-to-digital converter 2311 includes a first terminal, a second terminal and a third terminal, the first terminal of the analog-to-digital converter 2311 is connected to the power supply 2312, the second terminal of the analog-to-digital converter 2311 is connected to the contact 211, and the third terminal of the analog-to-digital converter 2311 is grounded; one end (end B) of resistive strip 221 is grounded, the other end (end C) of resistive strip 221 is connected to power supply 2312, and contact 211 makes contact with location D on resistive strip 221.

The processor 232 is connected to the detection circuit 231 and the driving device 24, and is configured to control the driving device 24 according to the digital voltage fed back by the detection circuit 231; specifically, the driving device 24 includes a driver 241 and a motor 242 connected to each other, and the driver 241 is configured to receive the angle difference sent by the processor 232 and drive the motor 242 according to the angle difference, so that the motor 242 drives the lens barrel 22 to rotate.

In another specific embodiment, as shown in fig. 3, a temperature sensor 212 is further disposed on the lens 21, the temperature sensor 212 can be used to detect the temperature of the lens 21, one end of the temperature sensor 212 is connected to the analog-to-digital converter 2311, and the other end of the temperature sensor 212 is grounded; specifically, as shown in fig. 4, the temperature sensor 212 is connected to the fourth terminal of the analog-to-digital converter 2311, and in order to prevent the temperature sensor 212 from being damaged due to excessive current flowing through the temperature sensor 212, a current limiting resistor 2313 may be provided, one end of the current limiting resistor 2313 is connected to the power supply 2312, and the other end of the current limiting resistor 2313 is connected to the fourth terminal of the analog-to-digital converter 2311.

The analog-to-digital converter 2311 is further configured to convert the voltage across the temperature sensor 212 into a second digital voltage and feed the second digital voltage back to the processor 232, and the processor 232 is configured to calculate a compensation angle corresponding to the thermal defocus according to the second digital voltage.

Since the relationship between the temperature and the angle to be compensated for the thermal defocus of the lens 21 monotonously changes, the voltage of the lens 21 of the target projection size at different temperatures and the angle to be compensated for can be measured and stored.

With continued reference to fig. 3, the auto-focusing apparatus further includes a memory 25, the memory 25 is connected to the processor 232, and is configured to store the voltages of the temperature sensors 212 at different temperatures and the corresponding compensation angles; specifically, the Memory 25 may be an Electrically Erasable Programmable Read Only Memory (EEPROM).

In a specific embodiment, the processor 232 is further configured to fit the data in the memory 25 to obtain a functional relationship between the voltage of the temperature sensor 212 and the compensation angle, and calculate the compensation angle corresponding to the voltage of the temperature sensor 212 by using the functional relationship; specifically, the temperature sensor 212 may be a thermistor, and may determine the real-time temperature of the lens 21 according to the voltage on the thermistor changing with the temperature, and calculate the angle to be compensated at the current temperature by matching the fitted functional relationship.

In another specific embodiment, the processor 232 may use the data in the memory 25 to establish a mapping table between the voltage of the temperature sensor 212 and the compensation angle, and use the voltage of the temperature sensor 212 to perform a lookup in the mapping table to obtain the corresponding compensation angle.

With continued reference to fig. 3, the auto-focusing apparatus further includes a distance measuring sensor 26, wherein the distance measuring sensor 26 is connected to the processor 232, and is configured to measure a projection distance between the lens 21 and the target object and send the projection distance to the processor 232.

The processor 232 is further configured to obtain an imaging angle of the lens barrel 22 according to the projection distance and the design parameter of the lens 21, and calculate an angle difference by using the imaging angle, the current angle, and the compensation angle; specifically, the design parameter may include an imaging angle, or the design parameter and the imaging angle have a mapping relationship therebetween, and the imaging angle corresponding to the design parameter may be obtained according to the mapping relationship therebetween.

In a specific embodiment, processor 232 may calculate the angle difference using the following equation:

wherein the content of the first and second substances,

is the angle difference, gamma is the imaging angle, alpha is the current angle, beta is the compensation angle.

After the projection distance is obtained through the distance measuring sensor 26, the angle of the lens 21 capable of imaging clearly can be obtained according to the design parameters of the lens 21, the current angle of the lens barrel 22 can be calculated through the contact voltage, the compensation angle can be calculated through the voltage on the temperature sensor 212, then the motor 242 can be controlled to drive the lens barrel 22 to rotate, and the compensation angle can be adjusted again according to the real-time temperature of the lens 21 in the subsequent working process.

The auto-focusing device provided by the embodiment directly pastes the resistor strip 221 on the lens barrel 22, the auto-focusing is assisted by detecting the rotation angle of the lens barrel 22, a new structure is not added for matching, the structure is simple, the cost is low, the elastic sheet 222 can be used for propping against the lens barrel 22, the gap is prevented from being generated so as to avoid generating forward and reverse idle stroke errors, the influence of the structure matching gap is reduced, the angle detection is accurate, the current angle of the lens barrel 22 can be indicated in real time, the temperature of the lens 21 can be detected, the projection distance is matched, and the heat defocusing can be compensated in real time.

The above embodiments are merely examples, and not intended to limit the scope of the present application, and all modifications, equivalents, and flow charts using the contents of the specification and drawings of the present application, or those directly or indirectly applied to other related arts, are included in the scope of the present application.

Claims

1. An automatic focusing device is characterized by comprising a lens, a lens barrel, a controller and a driving device, wherein a resistor strip is arranged on the lens barrel, a contact point which is in contact with the resistor strip is arranged on the lens, at least one end of the resistor strip is connected with the controller, and the contact point is connected with the controller;

the controller is used for detecting the contact voltage on the contact, obtaining the current angle of the lens cone according to the contact voltage, and obtaining the angle difference required by the rotation of the lens cone according to the imaging angle and the current angle which are obtained in advance;

the driving device is connected with the controller and is used for driving the lens barrel to rotate so as to reduce the angle difference;

the contact voltage detected by the controller varies following the rotation of the lens barrel.

2. The autofocus device of claim 1,

the contact is a spring plate which is propped against the lens cone to prevent the generation of forward and reverse idle stroke errors.

3. The autofocus device of claim 1, wherein the controller comprises:

the detection circuit is used for carrying out analog-to-digital conversion processing on the contact voltage to obtain a digital voltage;

and the processor is connected with the detection circuit and the driving equipment and is used for controlling the driving equipment according to the digital voltage fed back by the detection circuit.

4. The auto-focusing device according to claim 3,

the detection circuit comprises an analog-to-digital converter and a power supply which are connected with each other, wherein the analog-to-digital converter is used for converting the contact voltage into a first digital voltage and feeding the first digital voltage back to the processor;

the analog-to-digital converter comprises a first end, a second end and a third end, wherein the first end of the analog-to-digital converter is connected with the power supply, the second end of the analog-to-digital converter is connected with the contact, and the third end of the analog-to-digital converter is grounded; one end of the resistor strip is grounded, and the other end of the resistor strip is connected with the power supply.

5. The auto-focusing device according to claim 4,

the lens is also provided with a temperature sensor, one end of the temperature sensor is connected with the analog-to-digital converter, and the other end of the temperature sensor is grounded;

the analog-to-digital converter is also used for converting the voltage on the temperature sensor into a second digital voltage and feeding the second digital voltage back to the processor; and the processor is used for calculating a compensation angle corresponding to thermal defocusing according to the second digital voltage.

6. The auto-focusing device according to claim 5,

the automatic focusing device also comprises a ranging sensor, wherein the ranging sensor is connected with the processor and is used for measuring the projection distance between the lens and a target object and sending the projection distance to the processor; the processor is further configured to obtain the imaging angle according to the projection distance and design parameters of the lens, and calculate the angle difference by using the imaging angle, the current angle, and the compensation angle.

7. The auto-focusing device according to claim 6,

the processor calculates the angle difference using the following formula:

wherein the content of the first and second substances,

and the angle difference is determined, gamma is the imaging angle, alpha is the current angle, and beta is the compensation angle.

8. The auto-focusing device according to claim 6,

the automatic focusing device also comprises a memory, wherein the memory is connected with the processor and is used for storing the voltages of the temperature sensors at different temperatures and corresponding compensation angles;

the processor is further configured to establish a mapping table between the voltage of the temperature sensor and the compensation angle by using the data in the memory, and search the mapping table by using the voltage of the temperature sensor to obtain a corresponding compensation angle.

9. The auto-focusing device according to claim 3,

the driving device comprises a driver and a motor which are connected with each other, wherein the driver is used for receiving the angle difference sent by the processor and driving the motor according to the angle difference so as to enable the motor to drive the lens barrel to rotate.