KR101337977B1 - Device and method for controlling quantity of incident light - Google Patents

Abstract

Disclosed are an incident light amount adjusting device applicable to an imaging device and a control method thereof. A device installed in an imaging device to adjust an amount of light incident on an image sensor, the polarizing plate unit of which at least one of the plurality of polarizing plates rotates around an optical axis according to a transmittance control signal, and an illuminance measuring unit measuring ambient brightness of the imaging device. A transmittance control signal for controlling the relative rotation angles of the plurality of polarizers or a drive signal for moving the polarizer part according to a result of comparing the ambient brightness with the reference brightness and the polarizer part according to the drive signal And a substrate driving unit moving to one of a first position and a second position, wherein the first position is a position on the incident light path, and the second position is an arbitrary position deviating from the incident light path. According to the present invention, the amount of incident light is controlled by adjusting the transmittance of the polarizing plate. Under the illumination conditions can be removed from the incident light path, the polarizing plate improves the low light transmittance properties to prevent degradation due to the polarizing plate.

Description

Device and method for controlling quantity of incident light

The present invention relates to an imaging device, and more particularly, to an incident light amount adjusting device applicable to an imaging device and a control method thereof.

In an imaging device such as a video camera or a camcorder for photographing a moving image, a DC IRIS lens (or an automatic IRIS lens, hereinafter referred to as a "DC IRIS lens") is used as an apparatus for adjusting the amount of incident light. The DC IRIS lens controls the amount of light incident on the image sensor by using an aperture for the light incident through the lens.

FIG. 1 is a cross-sectional view illustrating a configuration of an imaging device equipped with a DC IRIS lens, and FIG. 2 is a conceptual view illustrating a method of adjusting an incident light amount by an aperture in the DC IRIS lens of FIG. 1. In the drawings, it is assumed that light is incident from the upward direction to the downward direction.

The imaging device 1 is provided with an image sensor 5 at the lower part of the body 2 supporting the upper lens 3 and the lower lens 4, and passes through the upper lens 3 and the lower lens 4. It receives a light and converts it into an electrical signal. A filter unit 6, such as an optical low pass filter (OLPF) or an IR cut filter, may be interposed between the lower lens 4 and the image sensor 5.

In FIG. 1, the diaphragm 7 is disposed between the upper lens 3 and the lower lens 4, and the opening degree of the diaphragm 7 is adjusted according to the driving of the driving unit 8 connected to the diaphragm 7. The amount of light incident on the image sensor 5 is adjusted.

Referring to FIG. 2, the aperture 7 includes a first shutter member 11 fixed at a specific position, a second shutter member 12 that is movable back and forth relative to the first shutter member 11, and a second An arm member 14 for transmitting a driving force for moving the shutter member 12 back and forth, and a magnet member 15 coupled to one end of the arm member 14 to generate a driving force.

The driving unit 8 is disposed adjacent to the magnet member 15 of the aperture 7 and flows through the coil member 16 and the coil member 16 to generate a magnetic field for applying attraction / repulsion to the magnet member 15. It includes a driving circuit 17 for adjusting the magnitude and direction of the current, and may be, for example, a servo motor or a galvano meter.

The opening degree of the opening 13 is determined according to the magnitude of the current of the driving circuit 17, and when the amount of data output from the image sensor 5 is too dark based on the appropriate brightness, the aperture is opened. If the direction is too bright, the position of the arm member 14 is changed in the direction of closing the iris. That is, when the DC value of the appropriate brightness is used as the reference value, and the brightness data of the image sensor is converted into the DC value and input to the differential amplifier, the magnet member 15 changes the direction of the current when the voltage is larger or smaller than the DC reference value. The direction of the force applied to the change is changed and the opening degree of the aperture can be changed by changing the position of the arm member 14 coupled to the magnet member 15.

For example, when a current flows in one direction (clockwise in FIG. 2A) by the driving circuit 17, a magnetic field formed in the coil member 16 is a magnet member 15. It acts as a repulsive force to push the magnet member 15 generates a driving force in the moving direction away from the coil member 16, the arm member 14 and the arm member 14 connected to the magnet member 15 The connected second shutter member 12 also receives a driving force and moves in the same direction, so that the opening 13 between the first shutter member 11 and the second shutter member 12 is opened.

On the contrary, when a current flows to the coil member 16 in the other direction (counterclockwise in FIG. 2B) by the driving circuit 17, the magnetic field formed in the coil member 16 is a magnetic member ( 15 acts as a attracting force, the magnet member 15 generates a driving force in the moving direction closer to the coil member 16, the arm member 14 and the arm member (14) connected to the magnet member 15 ( The second shutter member 12 connected to the 14 also receives a driving force and moves in the same direction so that the opening 13 between the first shutter member 11 and the second shutter member 12 is closed.

As described above, in the method of adjusting the opening degree of the aperture, the depth of focus is changed by changing the opening and closing states of the aperture. When the structure of the aperture is simple, as shown in FIG. 2, a two-leafed aperture is used. In this case, the shape of the opening 13 is changed according to the open and closed states of the aperture. In addition, there is a problem in that the deterioration of the image is induced in the angled portion of the opening 13 when it proceeds to the closed state, and the phenomenon that the image is defocused than the open state occurs.

As another method of adjusting the incident light amount, an electronic shutter function provided by the image sensor may be used. The electronic shutter is a component used because it is difficult to operate the mechanical shutter every frame due to the characteristics of an imaging device such as a video camera, and the principle thereof will be described with reference to FIGS. 3 and 4.

3 is a circuit diagram showing an electronic shutter structure using a photodiode in the image sensor, and FIG. 4 is a signal diagram of the electronic shutter.

The discharge function of the photo diode is used to store the amount of charge generated in the photo diode only for a specific time (for example, for a time corresponding to the shutter speed) and output as image data. Before output, discharge is prohibited for a time corresponding to the shutter speed, and the amount of charge accumulated in the photodiode during that time is the amount of incident light per frame of the photodiode (or image sensor).

Referring to FIG. 4, the time corresponding to the shutter speed for each frame, that is, the electronic shutter time is until the readout pulse is input after the reset pulse, and the charge accumulated in the photodiode during the electronic shutter time when the readout pulse is input. Is output as pixel data. That is, by adjusting the timing of the reset pulse to adjust the accumulation time of the photodiode for each frame, the amount of charge accumulated in the photodiode is adjusted, and as a result, the incident light amount may be controlled.

As described above, when the incident light amount of the imaging device is adjusted using the electronic shutter, the following problems may occur under a fluorescent lamp environment.

Fluorescent lamps basically have the same frequency as the power supply frequency, which causes flicker. As a result, the brightness of the light and the color temperature of the light source change in synchronization with the power supply frequency. This is not well detected. However, for video cameras, the frame rate is not exactly synchronized with the frequency of the power supply. For video cameras, the NTSC standard frame rate is 59.94 Hz (50 Hz for PAL), which is a frequency that has its own phase divided by the oscillator circuit of the video camera itself. This is because errors in the range of several Hz occur at 60 Hz (NTSC region) or 50 Hz (PAL region) depending on the transmission path.

In this case, since the electronic shutter uses only a portion of the incident light every frame time, a change in brightness and color temperature caused by flicker of a fluorescent lamp vibrates at the harmonic frequency of the power frequency and the frame frequency of the video camera. This occurs, and there is a problem in that a phenomenon in which a light is brightened and darkened in the captured image, and a color rolling phenomenon in which the color of the light source changes is generated. This phenomenon has a problem in that the image is brighter and becomes more severe when a smaller shutter speed value is used. If the shutter speed is greater than the flicker frequency of the fluorescent lamp, the change of the brightness and the color temperature of the light source accumulates and the problem of the change of the brightness or the color temperature is alleviated.

As another method of controlling the amount of incident light, Korean Patent Publication No. 2010-0010669 discloses a polarization pattern formed on two lenses among lenses that receive light from a subject, thereby opening and closing the lens opening as the lens rotates. Korean Patent No. 104269 discloses a technique in which two polarizers are aligned between lenses in an optical system, and a technique of adjusting the amount of light incident on the optical system without changing the aperture size of the aperture by rotating one polarizer is disclosed. It is. In this case, since light must pass through a lens or a polarizing plate on which a polarization pattern is basically formed, there is a problem in that a portion of light transmission efficiency is reduced.

In the high light environment, the reduction of the transmission efficiency does not cause a big problem in the expression of the image because the dynamic range of the input image is larger than the dynamic range of the image sensor. There is a problem in that the low light characteristics of the image sensor are deteriorated.

Patent Document 1: Korean Patent Publication No. 2010-0010669 Tuk He Document 2: Korean Registered Patent No.1024269

The present invention is to provide an incident light amount control device and a control method for improving the low light characteristics by adjusting the amount of incident light through the control of the transmittance of the polarizing plate while preventing the lowering of transmittance due to the polarizing plate by removing the polarizing plate from the incident light path under a specific low light situation will be.

In addition, the present invention by using a polarizing plate to prevent the aperture shape of the aperture does not change to prevent the change of focus or the lens depth unnecessarily, and to fix the accumulation time of the image sensor so as not to cause a bleeding phenomenon or color rolling phenomenon It is to provide an incident light amount adjusting device and a control method thereof.

Other objects of the present invention will become readily apparent from the following description.

According to an aspect of the present invention, a device installed in an image pickup device to adjust an amount of light incident on an image sensor, wherein at least one of the plurality of polarizers rotates around an optical axis according to a transmittance control signal, An illuminance measuring unit measuring an ambient brightness, a transmittance control unit outputting a transmittance control signal controlling a relative rotation angle of the plurality of polarizing plates or a driving signal for moving the polarizing plate unit according to a result of comparing the ambient brightness with a reference brightness; And a substrate driver for moving the polarizer to one of a first position and a second position according to the driving signal, wherein the first position is a position on the incident light path, and the second position is an arbitrary position deviated from the incident light path. An incident light amount adjusting device is provided.

The driving signal may operate the substrate driver such that the polarizer is located at the second position when the ambient brightness is less than or equal to the reference brightness, and the polarizer is located at the first position when the ambient brightness is higher than the reference brightness. have.

The plurality of polarizers may be independently moved, and the substrate driver may move at least one of the plurality of polarizers to one of the first position and the second position according to the driving signal.

The reference brightness is divided into a first reference brightness and a second reference brightness that is darker than the first reference brightness, and the driving signal is all of the plurality of polarizers when the ambient brightness is higher than the first reference brightness. Wherein the plurality of polarizers are all located at the second position when the ambient brightness is less than or equal to the second reference brightness and wherein the plurality of polarizers are between the first reference brightness and the second reference brightness. The substrate driver may be operated such that only one of the polarizers is positioned at the first position.

When the ambient brightness is higher than the reference brightness, the transmittance controller may calculate a difference between the ambient brightness and the required brightness, and adjust the relative rotation angle according to the result.

The display device may further include an infrared cut filter attached to one or more surfaces of the plurality of polarizing plates to block infrared light of the incident light.

On the other hand, according to another aspect of the present invention, there is provided a control method of the incident light amount adjusting device installed in the image pickup device to adjust the amount of light incident to the image sensor by adjusting the transmittance of the polarizing plate portion and a recording medium in which a program for performing the same is recorded. .

According to an exemplary embodiment, a method of controlling an incident light amount adjusting device may include measuring ambient brightness of the imaging device, determining whether the ambient brightness is equal to or less than a predetermined reference brightness, and removing the polarizer according to the determination result. And moving to one of a first position and a second position, wherein the first position is a position on the incident light path, and the second position may be any position deviating from the incident light path.

When the ambient brightness is less than or equal to the reference brightness, the moving of the polarizing plate part may include determining a position of the polarizing plate part and driving signals for moving the polarizing plate part away from the incident light path only when the polarizing plate part is positioned on the incident light path. It may include the step of outputting to the substrate driver.

When the ambient brightness is higher than the reference brightness, the moving of the polarizing plate part may include: determining the position of the polarizing plate part and moving the polarizing plate part to be positioned on the incident light path only when the polarizing plate part is located out of the incident light path. The method may include outputting a driving signal to the substrate driver.

The polarizer may include a plurality of independently movable polarizers, and the moving of the polarizer may include outputting a driving signal to the substrate driver to move at least one of the plurality of polarizers to one of the first and second positions. Can be.

The reference brightness is divided into a first reference brightness and a second reference brightness that is darker than the first reference brightness, and the moving of the polarizing plate may include all of the plurality of polarizing plates when the ambient brightness is higher than the first reference brightness. The polarizer is located at the first position, and when the ambient brightness is less than the second reference brightness, all of the plurality of polarizers are located at the second location, and the ambient brightness is between the first reference brightness and the second reference brightness. In this case, only one of the plurality of polarizers may move the polarizer to be positioned at the first position.

If the ambient brightness is higher than the reference brightness, calculating a difference between the ambient brightness and the required brightness, and outputting a transmittance control signal for adjusting a relative rotation angle of the polarizer according to the calculation result. It may include.

Other aspects, features, and advantages will become apparent from the following drawings, claims, and detailed description of the invention.

According to the exemplary embodiment of the present invention, the light intensity may be improved by controlling the transmittance of the polarizing plate while removing the polarizing plate from the incident light path under specific low light conditions to prevent a decrease in transmittance due to the polarizing plate.

By not opening or closing the iris, it is possible to prevent the lens from being unnecessarily changed due to the shape change of the opening and to unnecessarily change the accumulation time of the image sensor so that the light becomes bright and dark in the captured image. There is no color rolling phenomenon in which the color changes depending on a light source such as a breeding phenomenon or a fluorescent lamp.

1 is a cross-sectional view showing the configuration of an imaging device equipped with a DC IRIS lens;
FIG. 2 is a conceptual diagram illustrating a method of adjusting an incident light amount by an aperture in the DC IRIS lens of FIG. 1;
3 is a circuit diagram showing an electronic shutter structure using a photodiode in the image sensor;
4 is a signal diagram of an electronic shutter,
5 is a block diagram illustrating an apparatus for adjusting incident light amount according to an embodiment of the present invention;
6 is a conceptual diagram for explaining a principle of controlling transmittance of a polarizing plate part;
7 is a cross-sectional view for describing a method for adjusting an incident light amount in an imaging device including an incident light amount adjusting device according to an embodiment of the present invention;
8 is a cross-sectional view showing a configuration of an imaging device including an incident light amount adjusting device according to an embodiment of the present invention;
9 is a flow chart of a control method of the incident light amount control apparatus according to an embodiment of the present invention,
10 is a flow chart of a control method of the incident light amount control apparatus according to another embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. In the present specification, when a part is "connected" to another part, this includes not only "directly connected" but also "indirectly connected" between other components in between. do.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a block diagram illustrating a configuration of an incident light amount adjusting apparatus according to an embodiment of the present invention, FIG. 6 is a conceptual diagram for describing a principle of controlling transmittance of a polarizing plate unit, and FIG. 7 is an incident light amount adjusting according to an embodiment of the present invention. It is sectional drawing for demonstrating the method of adjusting the incident light quantity in the imaging device including a device.

The incident light amount adjusting apparatus 100 according to an exemplary embodiment of the present invention may be applied to an image capturing apparatus including an image sensor such as a video camera or a camcorder to capture a moving image or a still image.

Referring to FIG. 5, the incident light amount adjusting apparatus 100 according to an exemplary embodiment of the present invention includes a polarizer 110, a transmittance controller 120, an illuminance measurer 130, and a substrate driver 140.

The polarizer 110 is basically disposed in an optical path through which light is incident on the image sensor of the imaging device, that is, in the incident optical path. The polarizer 110 includes a plurality of polarizers, and adjusts the cross phases of the plurality of polarizers according to the transmittance control signal from the transmittance controller 120 to change the transmittance of light passing through the polarizer 110.

The cross-phase control of the plurality of polarizers will be described with reference to FIG. 6. According to an exemplary embodiment, the polarizer 110 may include a first polarizer 111 and a second polarizer 112 that rotates relative to the first polarizer 111 about an optical axis.

When the first polarizing plate 111 and the second polarizing plate 112 have the same polarization direction, light transmitted through the first polarizing plate 111 may transmit 100% of the second polarizing plate 112 (FIG. 6A). ) Reference). However, when the second polarizing plate 112 has a polarization direction perpendicular to each other by rotating by 90 degrees, the light transmitted through the first polarizing plate 111 does not transmit the second polarizing plate 112 (FIG. 6B). ) Reference).

Therefore, the rate at which light transmitted through the first polarizing plate 111 passes through the second polarizing plate 112 changes according to the rotation angle of the second polarizing plate 112, and this ratio passes directly through the polarizing plate unit 110. The transmittance of light is determined.

6 illustrates that only the second polarizing plate 112 is rotated, but according to an embodiment, only the first polarizing plate 111 may rotate or both the first and second polarizing plates 111 and 112 may rotate. will be.

The transmittance controller 120 controls the transmittance of the polarizer 110 by changing the cross phase of the plurality of polarizers included in the polarizer 110, that is, the relative rotation angle. The correlation between the relative rotation angles of the plurality of polarizing plates and the transmittance may be defined, for example, in the form of graphs, equations, lookup tables, and the like.

The transmittance controller 120 determines a transmittance of the polarizer 110 to allow sufficient light to be incident on the image sensor, and uses a predefined graph or equation for the relative rotation angles of the plurality of polarizers to achieve the corresponding transmittance. By calculating or searching from the look-up table and transmits the transmittance control signal to the polarizing plate 110 so that the polarizing plate is rotated.

The illuminance measuring unit 130 measures the peripheral illuminance of the imaging device on which the incident light amount adjusting device 100 is mounted. For example, brightness information may be obtained from a result of analyzing image data output from an image sensor, or brightness information may be obtained from a signal sensed by an illuminance sensor separately provided in the imaging apparatus.

If the image data is in YCbCr format or YUV format, the brightness information can be calculated using the arithmetic mean of the Y value representing the brightness of each pixel.If the image data has RGB format, YCbCr format or YUV format can be used. Through the format conversion process of converting to, Y value can be obtained and brightness information can be calculated therefrom. Format conversion will be apparent to those skilled in the art, and a detailed description thereof will be omitted.

The transmittance controller 120 may determine whether the current brightness is the required brightness based on the brightness information obtained by the illuminance measuring unit 130, and determine the transmittance so that the corresponding brightness may be achieved if the brightness is not required. .

In addition, the transmittance control unit 120 may determine that the image pickup device is placed in or out of a predetermined low light condition based on the ambient brightness information acquired by the illuminance measurement unit 130, that is, in a state of being brighter than the predetermined reference brightness. The driving signal is output to the substrate driver 140 when the light state changes to a dark state or a light state is changed from a dark state to a predetermined reference brightness.

The substrate driver 140 moves the polarizer 110 from the first position to the second position or from the second position to the first position according to the driving signal output from the transmittance controller 120. The substrate driver 140 may be rotated by a predetermined angle in one direction or another direction according to a drive signal, for example, a servo motor or a galvanometer, or may be moved by a predetermined length in one direction or another direction according to a drive signal, such as a linear motor. It may be a device.

Here, the first position is an arbitrary position on the incident light path to allow the incident light to pass through the polarizing plate 110, and the second position is to allow the incident light to enter the image sensor without passing through the polarizing plate 110. An arbitrary position deviated from the incident light path, and the movement of the polarizer 110 may vary depending on the design structure of the imaging device, such as, for example, rotation or forward and backward movement. That is, the substrate driver 140 may position or remove the polarizer 110 on the incident light path according to the driving signal from the illuminance measuring unit 130.

When the polarizing plate unit 110 is on the incident light path, even though the transmittance of the polarizing plate unit 110 is maintained in a high state, the transmission efficiency decreases to some extent through the plurality of polarizing plates.

Under high light conditions, the dynamic range of the input image is larger than the dynamic range of the image sensor, which does not cause a big problem in the representation of the image output from the image sensor. However, under low light amount, low light characteristics are deteriorated due to a decrease in transmittance due to the presence of the polarizer 110.

Therefore, the incident light amount adjusting apparatus 100 according to the present embodiment basically positions the polarizing plate unit 110 on the incident light path so that continuous incident light amount adjustment is possible. However, the polarizing plate unit 110 is less than a predetermined reference brightness. ) Can be removed from the incident light path, thereby eliminating the decrease in transmittance caused by the polarizer 110, thereby improving the low light characteristics.

Referring to FIG. 7, the polarizer 110 is positioned in the incident light path according to the operation of the substrate driver 140 (see FIG. 7A) and the polarizer 110 is removed from the incident light path. (See FIG. 7B) is illustrated. In FIG. 7, the polarizing plate part 110 of the incident light amount adjusting device 100 is illustrated as being disposed between the lower lens 4 and the image sensor 5, but this is only an example. As shown in FIG. 8, it may be disposed anywhere between the upper lens 3 and the lower lens 4 or on a path through which light is incident on the image sensor 5 such as the upper lens 3.

The polarizing plate unit 110 of the incident light amount adjusting apparatus 100 according to the present embodiment may include an infrared cut filter. The infrared cut filter may be attached to one or more surfaces of the plurality of polarizers.

The infrared cut-off filter is a filter that blocks infrared light among incident light, and it is necessary to be removed from the incident light path so that the transmittance of infrared light does not decrease when photographing using infrared light at low illumination, which is included in the polarizer 110. In this case, the position is changed according to the driving of the substrate driving unit 140, and thus, in a low light condition, the position is removed from the incident light path to prevent a decrease in transmittance of infrared light.

8 is a cross-sectional view illustrating a configuration of an imaging apparatus including an incident light amount adjusting device according to an embodiment of the present invention.

The incident light amount adjusting device 100 according to the present exemplary embodiment adjusts the amount of light incident on the light path before the light is incident on the image sensor 5, that is, on the incident light path. To this end, the polarizing plate 110 of the incident light amount adjusting device 100 is disposed between the lower lens 4 and the image sensor 5 (see FIG. 8A), and between the upper lens 3 and the lower lens 4. (See (b) of FIG. 8), the upper portion of the upper lens 3 (see (c) of Figure 8) can be located at any one.

In addition, the polarizing plate 110 of the incident light amount adjusting device 100 is disposed at an arbitrary position on a path through which the light incident to the image sensor 5 passes, thereby adjusting the amount of light before light is incident on the image sensor 5. Could be.

9 is a flowchart illustrating a control method of an incident light amount adjusting apparatus according to an embodiment of the present invention. Each step described below may be performed by each internal component of the incident light amount adjusting device 100 according to an embodiment of the present invention.

In operation S210, the incident light amount adjusting device 100 measures the peripheral illuminance. The measurement of the peripheral illuminance may be performed by analyzing brightness of the image data output from the image sensor or by obtaining brightness information from a sensing signal of the illuminance sensor included in the imaging device.

In operation S220, it is determined whether the measured ambient illuminance is equal to or less than a predetermined reference brightness. Under certain low light, the presence of the polarizing plate itself lowers the characteristics of the output image, in order to prevent this phenomenon.

If the ambient illuminance is lower than or equal to the reference brightness, the flow proceeds to step S230 to determine the position of the polarizer. If the position of the polarizing plate portion is located on the L1 position, that is, the incident light path, the process proceeds to step S240 to generate a driving signal in the substrate driver to remove the polarizing plate portion on the incident light path. If the position of the polarizing plate portion is located outside the L2 position, that is, the incident light path, the polarizing plate part is already removed on the incident light path, and the flow proceeds to step S250 to maintain the position of the polarizing plate part.

If the ambient illuminance is higher than the reference brightness, i.e., not in a low illuminance situation, the flow advances to step S260 to determine the position of the polarizing plate portion.

If the position of the polarizing plate portion is located out of the L2 position, that is, the incident light path, the substrate driver generates a driving signal to move the polarizing plate portion so that the polarizing plate portion is positioned on the L1 position, that is, the incident light path, in step S270, and then proceeds to step S280. When the position of the polarizing plate portion is located at the L1 position, that is, the incident light path, the step S270 is skipped and the flow proceeds directly to the step S280.

It is determined whether the ambient illuminance measured in step S280 is the required brightness, and when the brightness is not required, the transmittance of the polarizing plate part for obtaining the corresponding brightness is determined. Correlation between transmittance and brightness of the polarizer may be statistically determined through experiments.

In operation S290, the cross phase of the polarizing plate portion, that is, the relative rotation angle of the plurality of polarizing plates, is calculated to obtain the determined transmittance of the polarizing plate portion, and the transmittance control signal for rotating at least one of the plurality of polarizing plates is output to the polarizing plate so that the incident light amount is adjusted. do. The correlation between the transmittance and the applied voltage of the polarizer may be determined in the form of a graph or in the form of an equation, a lookup table, or the like.

It is apparent that the above-described method for controlling the incident light amount adjusting device may be performed by an automated procedure according to a time series sequence by a software program or the like embedded in the incident light amount adjusting device 100. The codes and code segments that make up the program can be easily deduced by a computer programmer in the field. In addition, the program is stored in a computer-readable information storage medium, and the program is read and executed by a computer to implement the method. The information storage medium includes a magnetic recording medium, an optical recording medium, and a carrier wave medium.

In the above description, the polarizing plate is positioned on the incident light path or when the polarizing plate is removed from the incident light path.

According to another embodiment of the present invention, the plurality of polarizing plates constituting the polarizing plate portion may move independently of each other.

The plurality of polarizing plates are provided between the lower lens 4 and the image sensor 5 (first position, see FIG. 8A), between the upper lens 3 and the lower lens 4 (second position, FIG. 8). (b)) and the upper portion of the upper lens 3 (third position, see Fig. 8 (c)) can be installed adjacent to each other.

Alternatively, each of the plurality of polarizing plates may be provided spaced apart from each other at any one of the first to third positions. In this case, the lower lens 4 and / or the upper lens 5 may be disposed between the plurality of polarizing plates. In this case, the degree of freedom of installation of the polarizing plate may be increased, so that a limited space may be efficiently utilized in the imaging device, and the substrate driving unit and / or transmittance control unit for moving the polarizing plate may be miniaturized and the degree of freedom of arrangement may be increased. Even if the polarizing plates are spaced apart, the transmittance control through the cross phase adjustment is performed in the same manner as described with reference to FIG. 6.

According to another embodiment of the present invention, the plurality of polarizers may move independently of each other so that the measured peripheral illuminance may be compared with a preset first reference brightness and second reference brightness (here, second reference brightness <first reference brightness). Depending on how much brightness there is, only one of the plurality of polarizers may be preferentially removed from the incident light path, or all of the plurality of polarizers may be removed from the incident light path.

10 is a flowchart illustrating a control method of an incident light amount adjusting apparatus according to another embodiment of the present invention. Each step described below may be performed by each internal component of the incident light amount adjusting device according to another embodiment of the present invention.

In operation S310, the incident light amount adjusting device measures the ambient illuminance IL.

If the peripheral illuminance IL is higher than the first reference brightness IL1 predetermined in step S320, the flow proceeds to step S330 so that the entire polarizing plate part is positioned at the L1 position, that is, the incident light path. The polarizing plate in L2 position among the some polarizing plates which comprise a polarizing plate part moves to L1 position, and the polarizing plate already in L1 position maintains the position.

If the peripheral illuminance IL is a value between the first reference brightness IL1 and the second reference brightness IL2 that are specified in step S340 (where IL1> IL2), the process proceeds to step S360, and the peripheral illuminance IL is If it is less than or equal to the second reference brightness IL2, the flow proceeds to step S350.

In step S360, the polarizing plate to be moved is selected, and in step S370, the selected polarizing plate is moved to the L2 position. That is, only one polarizing plate is positioned at the L1 position, thereby improving the transmission efficiency lowered each time passing through the polarizing plate in a low light condition in which incident light quantity exists to some extent.

In operation S350, the entire polarizer portion is positioned at an L2 position, that is, away from the incident light path. Of the plurality of polarizing plates constituting the polarizing plate portion, the polarizing plate at the L1 position is moved to the L2 position, and the polarizing plate already at the L2 position maintains the position.

Under low light conditions where the amount of incident light itself is very low, all of the polarizing plates may be removed from the incident light path to prevent a decrease in transmission efficiency caused by passing through the polarizing plates.

It is apparent that the above-described method for controlling the incident light amount adjusting device may be performed by an automated procedure according to the time series by a software program or the like embedded in the incident light amount adjusting device according to another embodiment of the present invention. The codes and code segments that make up the program can be easily deduced by a computer programmer in the field. In addition, the program is stored in a computer-readable information storage medium, and the program is read and executed by a computer to implement the method. The information storage medium includes a magnetic recording medium, an optical recording medium, and a carrier wave medium.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the following claims And changes may be made without departing from the spirit and scope of the invention.

100: incident light amount adjusting device 110: polarizing plate portion
120: transmittance control unit 130: roughness measuring unit
140: substrate driver 111: first polarizing plate
112: second polarizing plate

Claims (13)

A device installed in the imaging device to adjust the amount of light incident on the image sensor,
A polarizing plate unit in which at least one of the plurality of polarizing plates rotates about an optical axis according to a transmittance control signal;
An illuminance measuring unit measuring ambient brightness of the imaging device;
According to a result of comparing the ambient brightness with a first reference brightness and a second reference brightness darker than the first reference brightness, the transmittance control signal for controlling the relative rotation angle of the plurality of polarizing plates or a driving signal for moving the polarizing plate portion An output transmittance control unit; And
A substrate driver for moving at least one of the plurality of polarizing plates to one of a first position and a second position in accordance with the drive signal,
The first position is a position on the incident light path, the second position is an arbitrary position deviating from the incident light path,
The plurality of polarizing plates are independently movable,
The driving signal includes all of the plurality of polarizers positioned at the first position when the ambient brightness is higher than the first reference brightness, and all of the plurality of polarizers are positioned at the second position when the ambient brightness is less than the second reference brightness. And the substrate driver operating the substrate driver such that only one of the plurality of polarizers is positioned at the first position when the ambient brightness is between the first reference brightness and the second reference brightness. Device. delete delete delete The method of claim 1,
If the ambient brightness is higher than the first reference brightness,
And the transmittance controller calculates a difference between the ambient brightness and the required brightness, and adjusts the relative rotation angle according to the result. The method of claim 1,
And an infrared ray blocking filter attached to one or more surfaces of the plurality of polarizing plates to block infrared light among the incident light. A control method of an incident light amount adjusting device installed in an imaging device to adjust an amount of light incident on an image sensor by adjusting a transmittance of a polarizer.
Measuring ambient brightness of the imaging device;
Comparing the ambient brightness with a first reference brightness and a second reference brightness darker than the first reference brightness; And
And moving the polarizer to one of a first position and a second position according to the comparison result.
The first position is a position on the incident light path, the second position is an arbitrary position deviating from the incident light path,
The polarizing plate portion includes a plurality of independently movable polarizing plate,
The moving of the polarizer may include outputting a driving signal to the substrate driver to move at least one of the plurality of polarizers to one of the first and second positions.
The moving of the polarizer may include all of the plurality of polarizers positioned at the first position when the ambient brightness is higher than the first reference brightness, and all of the plurality of polarizers when the ambient brightness is less than the second reference brightness. Positioned at the second position, and when the peripheral brightness is between the first reference brightness and the second reference brightness, moving the polarizer part such that only one of the plurality of polarizers is located at the first location. Control method of the incident light amount adjusting device. The method of claim 7, wherein
When the ambient brightness is less than or equal to the second reference brightness, the moving of the polarizer may include:
Identifying positions of the plurality of polarizers;
And outputting a driving signal to a substrate driver to move the polarizing plate positioned on the incident light path out of the incident light path only when at least one of the plurality of polarizing plates is located on the incident light path. Control method of light intensity control device. The method of claim 7, wherein
When the peripheral brightness is higher than the first reference brightness, the moving of the polarizer may include:
Identifying positions of the plurality of polarizers;
And outputting a driving signal to a substrate driver to move the polarizer, which is located off the incident light path, to be positioned on the incident light path only when at least one of the plurality of polarizing plates is located off the incident light path. Control method of the incident light amount adjusting device. delete delete The method of claim 7, wherein
If the ambient brightness is higher than the first reference brightness,
Calculating a difference between the ambient brightness and the required brightness; And
And outputting a transmittance control signal for adjusting a relative rotation angle of the polarizer according to the calculation result. The program of instructions that can be executed by the digital processing apparatus for performing the method of controlling the incident light amount adjusting apparatus according to any one of claims 7 to 9 and 12 is tangibly implemented and is implemented by the digital processing apparatus. Recordable media that can be read.

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