WO2022057667A1

WO2022057667A1 - Autofocus method and autofocus apparatus

Info

Publication number: WO2022057667A1
Application number: PCT/CN2021/116765
Authority: WO
Inventors: 唐云飞; 李屹
Original assignee: 深圳光峰科技股份有限公司
Priority date: 2020-09-16
Filing date: 2021-09-06
Publication date: 2022-03-24
Also published as: CN114200631A

Abstract

An autofocus method and an autofocus apparatus. The autofocus apparatus comprises a lens (11), a lens barrel (12), a controller (13) and a drive device (14). A resistor bar (121) is provided on the lens barrel (12). The lens (11) is provided with a contact (111) in contact with the resistor bar (121). At least one end of the resistor bar (121) is connected to the controller (13). The contact (111) is connected to the controller (13). The controller (13) is used to detect a contact voltage at the contact (111), to obtain a current angle of the lens barrel (12) according to the contact voltage, and to obtain an angle difference by which the lens barrel (12) needs to rotate according to an imaging angle acquired in advance and the current angle. The drive device (14) is connected to the controller (13), and is used to drive the lens barrel (12) to rotate so as to reduce the angle difference. The contact voltage detected by the controller (13) changes with rotation of the lens barrel (12). The autofocus apparatus can realize automatic focusing, and reduce costs.

Description

A kind of automatic focusing method and automatic focusing device

technical field

The present application relates to the field of projection technology, and in particular, to an automatic focusing method and an automatic focusing device.

Background technique

At present, most of the projection focusing can be achieved by rotating the lens barrel, but the fast autofocus achieved by measuring the projection distance needs to know the rotation angle of the lens barrel, and there is a problem of defocusing after the lens temperature rises, and the lens barrel needs to be rotated to adjust again; In addition, the distance sensor can also be used to measure the projection distance, and after knowing the current angle position of the lens, the direction and angle that need to be rotated at this time can be calculated according to the lens focusing specification, and then the motor is used to drive the lens to quickly complete the automatic focusing. The rotation angle is mostly realized by adjusting the number of steps of the motor, and the sensor needs to sense the starting position of the motor, and there are problems that the structural matching gap is difficult to eliminate, the motor has an idle stroke and the rotation angle calculation is inaccurate, resulting in a slow autofocus speed and poor experience. , while the cost of the externally installed angle sensor is high, and a new mechanism needs to be added for coordination, which is easy to introduce new errors.

SUMMARY OF THE INVENTION

The present application provides an automatic focusing method and an automatic focusing device, which can realize automatic focusing and reduce costs.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present application is to provide an automatic focusing device, the automatic focusing device includes a lens, a lens barrel, a controller and a driving device, the lens barrel is provided with a resistance bar, and the lens is provided with a At least one end of the resistance strip is connected to the controller, and the contact is connected to the controller; the controller is used to detect the contact voltage on the contact, and obtain the current angle of the lens barrel according to the contact voltage, and according to the preset The obtained imaging angle and the current angle are used to obtain the angle difference that the lens barrel needs to rotate; the driving device is connected to the controller to drive the lens barrel to rotate to reduce the angle difference; the contact voltage detected by the controller follows the mirror change according to the rotation of the cylinder.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present application is to provide an automatic focusing method, which is applied to an automatic focusing device. The automatic focusing device includes a lens, a lens barrel, a controller and a driving device, and a resistor is provided on the lens barrel. The lens is provided with a contact contact with the resistance strip, at least one end of the resistance strip is connected with the controller, and the contact is connected with the controller. The method includes: using the controller to detect the contact voltage on the contact, according to the contact The voltage is used to obtain the current angle of the lens barrel; the controller is used to obtain the angle difference that the lens barrel needs to rotate according to the pre-obtained imaging angle and the current angle; the controller is used to control the driving device to drive the lens barrel to rotate to reduce the angle difference; Among them, the contact voltage detected by the controller changes with the rotation of the lens barrel.

Through the above scheme, the beneficial effect of the present application is: the current angle of the lens barrel is detected by the resistance bar on the lens barrel and the contact point on the lens, the contact point and the resistance bar are in contact with each other, and when the lens barrel rotates, the resistance bar follows the movement , so that the contact position between the contact and the resistance strip changes, the controller can detect the voltage at the contact, and use the mapping relationship between the contact voltage and the current angle to calculate the current angle corresponding to the current contact voltage, and then Then use the imaging angle and the current angle to calculate the angle difference that the lens barrel needs to rotate. The lens barrel rotates under the action of the driving device, so that the angle difference becomes smaller, so that the picture captured by the lens is clear, because the contact voltage follows the lens barrel. Rotating and changing, it can achieve automatic focus, clear imaging, and the structure is simple, no need to add new mechanisms to match the contacts or resistance strips, no new errors are introduced, and costs can be saved.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort. in:

1 is a schematic structural diagram of an embodiment of an automatic focusing device provided by the present application;

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

3 is a schematic structural diagram of another embodiment of an autofocus device provided by the present application;

Fig. 4 is the connection schematic diagram of the analog-to-digital converter, the power source, the resistance bar and the temperature sensor in the embodiment shown in Fig. 3;

FIG. 5 is a schematic flowchart of an embodiment of an automatic focusing method provided by the present application.

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. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

Please refer to FIG. 1 . FIG. 1 is a schematic structural diagram of an embodiment of an auto-focusing device provided by the present application. The auto-focusing device includes a lens 11 , a lens barrel 12 , a controller 13 and a driving device 14 .

The lens 11 is a retractable structure, and a contact 111 is provided on the lens 11 . The contact 111 can be a conductor, and the contact 111 can be connected to the controller 13 through a wire.

The lens barrel 12 is connected with the lens 11, the lens barrel 12 is provided with a resistance bar 121 in contact with the contact 111, at least one end of the resistance bar 121 is connected with the controller 13, and the contact 111 is connected with the controller 13; 12 is provided with a chute (not shown in the figure), the resistance strip 121 is attached to the side of the chute, the contact point 111 protruding on the lens 11 is embedded in the chute and abuts with the resistance strip 121, the resistance of the resistance strip 121 The value changes uniformly with the length, which can be a carbon film or a resistance wire, and the opposite ends of the resistance bar 121 are respectively connected with wires. When the lens barrel 12 rotates, the resistance bar 121 follows the lens barrel 12 to move together, and the contact 111 and the resistance bar 121 The contact position of the controller 13 changes with the change; the controller 13 is used to detect the contact voltage on the contact 111, and the contact voltage detected by the controller 13 changes with the rotation of the lens barrel 12; for example, as shown in FIG. 2, at time t1 , the contact 111 is in contact with the position A of the resistance bar 121, the resistance value corresponding to the position A is R1, and the contact voltage detected by the controller 13 is recorded as U1; with the rotation of the lens barrel 12, at the moment t2, the contact 111 Contact with the position B of the resistance bar 121, the resistance value corresponding to the position B is R2, and the contact voltage detected by the controller 13 is recorded as U2.

The controller 13 is also used to obtain the current angle of the lens barrel 12 according to the contact voltage, and obtain the required rotation angle difference of the lens barrel 12 according to the pre-acquired imaging angle and the current angle of the lens barrel 12; specifically, the angle difference In order to make the angle of imaging clear, there is a mapping relationship 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; Moreover, there is a mapping relationship between the current angle of the lens barrel 12 and the imaging angle and the angle difference. According to the mapping relationship between the three, the current angle and the angle difference, the angle that the lens barrel 12 needs to rotate at present can be calculated. After being rotated, the imaging of the lens 11 can be made clear.

The driving device 14 can be connected with the lens barrel 12, which is used to drive the lens barrel 12 to rotate, so as to reduce the angle difference; specifically, the driving device 14 is connected with the controller 13, can receive the angle difference sent by the controller 13, and drive The lens barrel 12 is rotated, so that the lens barrel 12 is rotated to drive the lens 11 to move back and forth, so as to realize automatic focusing and clear imaging.

In other embodiments, the angle difference may also be the angular position of the lens barrel 12 , that is, the final angle of the lens barrel 12 , the implementation principle of which is similar to that of the above-mentioned embodiment, and will not be repeated here.

This embodiment provides an automatic focusing device. Contacts 111 and resistance bars 121 are respectively provided on the lens 11 and the lens barrel 12, and the contacts 111 and the resistance bars 121 are in contact with each other. When the lens barrel 12 rotates, the resistance bars 121 Following the movement, the contact position of the contact 111 and the resistance bar 121 changes, that is, the contact voltage changes, the controller 13 can detect the contact voltage, and use the contact voltage and the mapping relationship between the contact voltage and the current angle Calculate the current angle of the lens barrel 12, and then use the imaging angle and the current angle to calculate the required rotation angle of the lens barrel 12. The lens barrel 12 rotates under the action of the driving device 14, so that the picture captured by the lens 11 is clear. The voltage changes with the rotation of the lens barrel 12 , which enables automatic focusing and clear imaging.

Please refer to FIG. 3 . FIG. 3 is a schematic structural diagram of another embodiment of the auto-focusing device provided by the present application. In this embodiment, the contact point is a spring piece 222 .

The shrapnel 222 can withstand the lens barrel 22 to prevent the forward and reverse idle travel errors from appearing in the gap, and ensure the accurate mapping relationship between the contact voltage and the position of the contact 211; 222 contacts the resistance bar 221 that moves with the focus adjustment, and the contact 211 can be tightly matched with the resistance bar 221 in the chute through the elastic piece 222; for example, as shown in FIG. The resistance value between the relationship, that is, α=AU, and A is a constant.

The controller 23 includes a detection circuit 231 and a processor 232 that are connected to each other. The detection circuit 231 is connected to the resistance bar 221 for detecting the contact voltage, and performing analog-to-digital conversion processing 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, and the analog-to-digital converter 2311 is used for converting the contact voltage into a first digital voltage, and feeding back the first digital voltage to the The processor 232; specifically, the analog-to-digital converter 2311 can collect the contact voltage, and use the functional relationship between the angle of the lens barrel 22 and the contact voltage to calculate the angle of the lens barrel 22, that is, the current angle.

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, and the second terminal of the analog-to-digital converter 2311 is connected to the contact 211 is connected, the third end of the analog-to-digital converter 2311 is grounded; one end (B end) of the resistance bar 221 is grounded, the other end (C end) of the resistance bar 221 is connected to the power supply 2312, and the position of the contact 211 and the resistance bar 221 D contact.

The processor 232 is connected to the detection circuit 231 and the driving device 24, and is used for controlling the driving device 24 according to the digital voltage fed back by the detection circuit 231; It is used 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 , the lens 21 is further provided with a temperature sensor 212 . 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 . The other end of the sensor 212 is grounded; specifically, as shown in FIG. 4 , the temperature sensor 212 is connected to the fourth end of the analog-to-digital converter 2311. In order to prevent the current flowing through the temperature sensor 212 from being too large and causing damage to the temperature sensor 212, A current limiting resistor 2313 can be provided, one end of the current limiting resistor 2313 is connected to the power source 2312 , and the other end of the current limiting resistor 2313 is connected to the fourth end of the analog-to-digital converter 2311 .

The analog-to-digital converter 2311 is also used to convert the voltage on the temperature sensor 212 into a second digital voltage, and feed back the second digital voltage to the processor 232, and the processor 232 is used to calculate the corresponding thermal defocus according to the second digital voltage. Compensation angle.

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

Continuing to refer to FIG. 3 , the auto-focusing device further includes a memory 25, which is connected to the processor 232 and is used for storing the voltages of the temperature sensor 212 and the corresponding compensation angles at different temperatures; specifically, the memory 25 may be electrically erasable Programmable Read Only Memory (EEPROM, Electrically Erasable Programmable Read Only Memory).

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 use the functional relationship to calculate the corresponding voltage of the temperature sensor 212. Specifically, the temperature sensor 212 can be a thermistor, which can determine the real-time temperature of the lens 21 according to the change of the voltage on the thermistor with the temperature, and calculate the required temperature at the current temperature with the fitted functional relationship. Compensation angle.

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 search in the mapping table to obtain the corresponding Compensation angle.

Continuing to refer to FIG. 3 , the autofocus device further includes a ranging sensor 26 connected to the processor 232 for measuring the projection distance between the lens 21 and the target object, and sending the projection distance to the processor 232 .

The processor 232 is also used to obtain the imaging angle of the lens barrel 22 according to the projection distance and the design parameters of the lens 21, and use the imaging angle, the current angle and the compensation angle to calculate the angle difference; specifically, the design parameters may include the imaging angle, Or there is a mapping relationship between the design parameters and the imaging angle, and the imaging angle corresponding to the design parameters can be obtained according to the mapping relationship between the two.

In a specific embodiment, the processor 232 can use the following formula to calculate the angle difference:

in,

is the angle difference, γ is the imaging angle, α is the current angle, and β is the compensation angle.

After the projection distance is obtained through the ranging sensor 26 , the angle at which the lens 21 can image 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, and the current angle of the lens barrel 22 can be calculated through the voltage on the temperature sensor 212 . After compensating the angle, the motor 242 can be controlled to drive the lens barrel 22 to rotate, and the compensation angle can be readjusted according to the real-time temperature of the lens 21 during subsequent operations.

The auto-focusing device provided in this embodiment directly attaches the resistance bar 221 to the lens barrel 22, and assists the auto-focusing by detecting the rotation angle of the lens barrel 22, without adding a new structure for cooperation, the structure is simple, the cost is low, and the elastic piece 222 Can withstand the lens barrel 22, prevent the occurrence of gaps to avoid forward and reverse idle travel errors, reduce the influence of the structural matching gap, make the angle detection accurate, and can indicate the current angle of the lens barrel 22 in real time, and can detect the lens 21 The temperature and the projection distance can compensate for thermal defocus in real time.

Please refer to FIG. 5 . FIG. 5 is a schematic flowchart of an embodiment of an auto-focusing device provided by the present application. The method can be applied to the auto-focusing device shown in FIG. 1 . The auto-focusing device includes a lens 11 , a lens barrel 12 , and a controller 13 And the driving device 14, the lens barrel 12 is provided with a resistance bar 121, the lens 11 is provided with a contact 111 in contact with the resistance bar 121, at least one end of the resistance bar 121 is connected with the controller 13, and the contact 111 is connected with the controller 13 , the method includes:

Step 51: Use the controller to detect the contact voltage on the contact, and obtain the current angle of the lens barrel according to the contact voltage.

The contact 111 is in contact with the resistance bar 121 on the lens barrel 12. Since the controller 13 is connected to the contact 111, the controller 13 can be used to detect the voltage at the contact 111 (ie, the contact voltage). When the lens barrel 12 rotates , the resistance bar 121 rotates with the lens barrel 12 , and the contact 111 is fixed relative to the lens barrel 12 in the rotation direction of the lens barrel 12 , so the contact position of the contact 111 and the resistance bar 121 follows the rotation of the lens barrel 12 and change, so that the contact voltage changes with the rotation of the lens barrel 12. Since the contact voltage and the current angle of the lens barrel 12 have a mapping relationship, the controller 13 can use the mapping relationship to obtain the current detected contact voltage. The corresponding current angle.

Step 52: Use the controller to obtain the angle difference required to rotate the lens barrel according to the imaging angle and the current angle.

After the current angle of the lens barrel 12 is calculated by the controller 13 , the controller 13 can be used for calculation. The controller 13 can use the current angle of the lens barrel 12 and the imaging angle of the lens barrel 12 to calculate the current angle of the lens barrel 12 that needs to be rotated. angle to make the image clear.

Step 53: Use the controller to control the driving device to drive the lens barrel to rotate, so as to reduce the angle difference.

After calculating the angle that the lens barrel 12 needs to rotate, the controller 13 can be used to control the driving device 14, and the driving device 14 can receive the angle difference sent by the controller 13, so that the driving device 14 drives the lens barrel 12 to continue to rotate. After the rotation of the drum 12 reaches the angle difference, the driving device 14 is controlled to stop working, thereby realizing focusing.

The present embodiment provides a method for assisting auto-focusing by detecting the rotation angle of the lens barrel 12. A resistor strip 121 is attached to a specific position on the lens barrel 12 and a contact 111 is set at a specific position on the lens barrel 11. When rotating, the contact 111 continuously contacts different positions of the resistance bar 121, and the controller 13 can detect the change of the voltage to determine the current angle of the lens barrel 12, and then use the current angle and the imaging angle to calculate the angle that the lens barrel 12 needs to rotate, and The lens barrel 12 is driven to rotate to realize automatic focusing.

The above are only the embodiments of the present application, and are not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied in other related technical fields, All are similarly included in the scope of patent protection of the present application.

Claims

An automatic focusing device is characterized in that it includes a lens, a lens barrel, a controller and a driving device, the lens barrel is provided with a resistance strip, the lens is provided with a contact contact with the resistance strip, the At least one end of the resistance bar is connected with the controller, and the contact is connected with the controller;

The controller is used to detect the contact voltage on the contact, obtain the current angle of the lens barrel according to the contact voltage, and obtain the lens barrel according to the pre-obtained imaging angle and the current angle The angle difference of the required rotation;

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 changes with the rotation of the lens barrel.
The automatic focusing device according to claim 1, wherein,

The contacts are elastic pieces, and the elastic pieces bear against the lens barrel to prevent the forward and reverse idle stroke errors.
The automatic focusing device according to claim 1, wherein the controller comprises:

a detection circuit for performing analog-to-digital conversion processing on the contact voltage to obtain a digital voltage;

A processor, connected to the detection circuit and the driving device, is configured to control the driving device according to the digital voltage fed back by the detection circuit.
The automatic focusing device according to claim 3, wherein,

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

The analog-to-digital converter includes a first end, a second end and a third end, the first end of the analog-to-digital converter is connected to the power supply, and the second end of the analog-to-digital converter is connected to the power supply. The contacts are connected, and the third end of the analog-to-digital converter is grounded; one end of the resistance bar is grounded, and the other end of the resistance bar is connected to the power supply.
The automatic focusing device according to claim 4, wherein,

The lens is also provided with a temperature sensor, one end of the temperature sensor is connected to 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 back the second digital voltage to the processor; the processor is used for according to the second digital voltage The voltage calculates the compensation angle corresponding to thermal defocus.
The automatic focusing device according to claim 5, wherein,

The automatic focusing device further includes a ranging sensor, which is connected to the processor for measuring the projection distance between the lens and the 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 the design parameters of the lens, and calculate the angle difference by using the imaging angle, the current angle and the compensation angle.
The automatic focusing device according to claim 6, wherein,

The processor uses the following formula to calculate the angle difference:

in,
is the angle difference, γ is the imaging angle, α is the current angle, and β is the compensation angle.
The automatic focusing device according to claim 6, wherein,

The automatic focusing device further includes a memory, which is connected to the processor and is used for storing the voltage of the temperature sensor and the corresponding compensation angle at different temperatures;

The processor is further configured to fit the data in the memory, obtain a functional relationship between the voltage of the temperature sensor and the compensation angle, and use the functional relationship to calculate the voltage corresponding to the temperature sensor. the compensation angle; or

A mapping table between the voltage of the temperature sensor and the compensation angle is established by using the data in the memory, and the corresponding compensation angle is obtained by searching in the mapping table by using the voltage of the temperature sensor.
The automatic focusing device according to claim 3, wherein,

The driving device includes a driver and a motor that are connected to each other, the driver is configured to receive the angle difference sent by the processor, and drive the motor according to the angle difference, so that the motor drives the lens barrel turn.
An automatic focusing method is characterized in that it is applied to an automatic focusing device, the automatic focusing device includes a lens, a lens barrel, a controller and a driving device, the lens barrel is provided with a resistance bar, and the lens is provided with a The contact point contacted by the resistance strip, at least one end of the resistance strip is connected with the controller, the contact point is connected with the controller, and the method includes:

Use the controller to detect the contact voltage on the contact, and obtain the current angle of the lens barrel according to the contact voltage;

Using the controller to obtain the angle difference required to rotate the lens barrel according to the pre-obtained imaging angle and the current angle;

The controller is used to control the driving device to drive the lens barrel to rotate, so as to reduce the angle difference; the contact voltage detected by the controller changes with the rotation of the lens barrel.