Camera system and driving method therefor

Abstract

To provide a camera system capable of more finely adjusting sensitivity.SOLUTION: A camera system comprises: a photoelectric conversion unit including a photoelectric conversion layer for converting incident light to electric charge, a first electrode positioned on a side of the photoelectric conversion layer on which the light is incident, and a second electrode that faces the first electrode via the photoelectric conversion layer; a voltage supply circuit for supplying first voltage and second voltage lower than the first voltage between the first electrode and the second electrode; and a control circuit. The control circuit calculates a length of time corresponding to an attenuation factor set for a first frame and make the voltage supply circuit supply the first voltage and the second voltage between the first electrode and the second electrode so that a length of an application time of the first voltage becomes the length of time in the first frame.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present disclosure relates to a camera system capable of electrically changing sensitivity and a method for driving the same. [Background technology]

[0002] In recent years, a method has been proposed for adjusting illuminance using not only an aperture or a shutter but also a so-called electronic ND (Neutral Density) filter function (see, for example, Patent Document 1). In this method, a voltage is applied so that the transmittance corresponds to the illuminance, and the illuminance is electrically adjusted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-88596 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for camera systems that can more precisely adjust their sensitivity to changes in brightness. [Means for solving the problem]

[0005] A camera system according to one embodiment of the present disclosure includes a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into an electric charge, a first electrode located on the side of the photoelectric conversion layer where light is incident, and a second electrode that faces the first electrode via the photoelectric conversion layer, a voltage supply circuit that applies a first voltage and a second voltage smaller than the first voltage between the first electrode and the second electrode, and a control circuit, wherein the control circuit determines a length of time corresponding to an attenuation rate set for a first frame, and causes the voltage supply circuit to apply the first voltage and the second voltage between the first electrode and the second electrode in the first frame so that the length of application time of the first voltage becomes the length of time. Effect of the Invention

[0006] According to the present disclosure, it is possible to provide a camera system etc. that can more finely adjust the sensitivity to changes in brightness. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a functional block diagram showing the configuration of a camera system according to the first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of a user I / F unit. [Diagram 3] FIG. 3 is a diagram illustrating the configuration of the first conversion unit and the second conversion unit in the camera system according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating a method of adjusting the sensitivities of the first conversion means and the second conversion means in the camera system according to the first embodiment. [Diagram 5] FIG. 5 is a schematic cross-sectional view of a frequency filter. [Figure 6] FIG. 6 is a graph illustrating the frequency characteristics of a frequency filter. [Figure 7] FIG. 7 is a functional block diagram showing a configuration of a camera system according to the first modification of the first embodiment. [Figure 8] FIG. 8 is a table showing control patterns of the first conversion means and the second conversion means in the first modification of the first embodiment. [Figure 9] FIG. 9 is a functional block diagram showing the configuration of a camera system according to the second embodiment. [Figure 10] FIG. 10 is a diagram illustrating the configuration of the first conversion means and the second conversion means in the camera system according to the second embodiment. [Figure 11] FIG. 11 is a graph showing the relationship between the voltage applied to the photoelectric conversion film and the output voltage from the light receiving section. [Figure 12] FIG. 12 is a flowchart showing a procedure for correcting the light sensitivity of a photoelectric conversion unit when the photoelectric conversion unit is used as an electronic ND filter. [Figure 13]FIG. 13 is an example of a timing chart for adjusting the light sensitivity by the voltage control method. [Figure 14] FIG. 14 is another example of a timing chart for adjusting the light sensitivity by the voltage control method. [Figure 15] FIG. 15 is an example of a timing chart for adjusting the optical sensitivity by the pulse duty control method. [Figure 16] FIG. 16 is another example of a timing chart for adjusting the optical sensitivity by the pulse duty control method. [Figure 17] FIG. 17 is a functional block diagram showing a configuration of a camera system according to a first modification of the second embodiment. [Figure 18] FIG. 18 is a diagram illustrating a method of adjusting the sensitivities of the first conversion means and the second conversion means in the first modification of the second embodiment. [Figure 19] FIG. 19 is a diagram illustrating a light receiving section in the second modification of the second embodiment. [Figure 20] FIG. 20 is a diagram for explaining the configuration of a photoelectric conversion unit in Modification 2 of the second embodiment. In FIG. [Figure 21] FIG. 21 is a diagram illustrating a method for adjusting the sensitivity of a photoelectric conversion unit in the second modification of the second embodiment. [Figure 22] FIG. 22 is a diagram illustrating a method for adjusting the sensitivity of a photoelectric conversion unit in the second modification of the second embodiment. [Figure 23] FIG. 23 is a functional block diagram showing a configuration of a camera system according to the third modification of the second embodiment. [Figure 24] FIG. 24 is a graph showing the relationship between the voltage applied to the photoelectric conversion film and the spectral characteristics of the wavelength. [Diagram 25] FIG. 25 is a functional block diagram showing the configuration of a camera system according to the third embodiment. [Figure 26] FIG. 26 is a diagram illustrating the configurations of the first conversion means and the second conversion means in the camera system according to the third embodiment. [Figure 27]FIG. 27 is a diagram illustrating a method of adjusting the sensitivities of the first conversion means and the second conversion means in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] It is known that an electronic ND filter can control the brightness of a captured image more uniformly than an aperture. In addition, an electronic ND filter can reduce degradation of image quality because it does not cause the diffraction phenomenon seen in an aperture. However, there is a demand for a more finely adjustable sensitivity to changes in brightness. The present disclosure provides an imaging device that can adjust the sensitivity to changes in brightness more finely.

[0009] An outline of one aspect of the present disclosure is as follows.

[0010] [Item 1] An imaging device comprising: a photoelectric conversion unit including a pixel electrode, a counter electrode, and a photoelectric conversion layer sandwiched between the pixel electrode and the counter electrode and configured to convert incident light into an electric charge; and a voltage application circuit configured to supply a voltage between the pixel electrode and the counter electrode, wherein the voltage application circuit supplies a first voltage having a constant voltage value in a first frame, and supplies a pulsed second voltage in a second frame different from the first frame.

[0011] [Item 2] An imaging device comprising: a photoelectric conversion unit including a photoelectric conversion layer having a first surface and a second surface opposite to the first surface and converting incident light into electric charges, a counter electrode located on the first surface, and a pixel electrode and an auxiliary electrode located on the second surface; and a voltage application circuit that supplies a voltage between the counter electrode and the auxiliary electrode, wherein the voltage application circuit supplies a first voltage having a constant voltage value in a first frame, and supplies a pulsed second voltage in a second frame different from the first frame.

[0012] [Item 3] 3. The imaging device according to item 1 or 2, wherein the voltage application circuit selectively supplies the first voltage and the second voltage in accordance with an ND value that is set for each frame.

[0013] [Item 4] 4. The imaging device according to item 3, wherein the voltage application circuit supplies the first voltage in frames in which an ND value is set to a first value or greater, and supplies the second voltage in frames in which an ND value is set to a value smaller than the first value.

[0014] [Item 5] 5. The imaging device according to item 4, wherein the voltage application circuit supplies the first voltage having a voltage value corresponding to the ND value in a frame in which the ND value is set to be equal to or greater than the first value.

[0015] [Item 6] 6. The imaging device according to item 4 or 5, wherein the voltage application circuit supplies the second voltage having a duty corresponding to an ND value set smaller than the first value in a frame.

[0016] [Item 7] 6. The imaging device according to item 4 or 5, wherein the voltage application circuit supplies the second voltage having a voltage value and duty corresponding to the ND value in a frame in which the ND value is set to a value smaller than the first value.

[0017] [Item 8] 8. The imaging device according to any one of items 1 to 7, further comprising an automatic / manual control unit that switches between an automatic mode in which the voltage applied by the voltage application circuit is changed in response to an intensity of incident light and a manual mode in which the voltage applied by the voltage application circuit is changed in response to an instruction from a user.

[0018] [Item 9] 9. A camera system comprising: the imaging device according to any one of items 1 to 8; a display; and a graphic interface unit that switches between displaying, on the display, a first image that accepts instructions for continuously changing a sensitivity and a second image that accepts instructions for gradually changing the sensitivity.

[0019] Moreover, an outline of one aspect of the present disclosure is as follows.

[0020] A camera system according to one aspect of the present disclosure includes a light receiving unit that converts incident light into an electrical signal, a first conversion means and a second conversion means that change the gain of the incident light in the process from when it is incident to when it is converted into an electrical signal by the light receiving unit in accordance with an applied voltage, and an applied voltage control unit that applies a voltage to the first conversion means and the second conversion means, and the second conversion means is disposed at a position where light that has passed through the first conversion means is incident.

[0021] Since there are two conversion means in this way, the gain can be changed independently. Therefore, the sensitivity to changes in brightness can be adjusted more finely. In addition, by having two conversion means, the gain change that would be performed by one conversion means is performed by two conversion means, so the size of one conversion means can be reduced. Furthermore, since the applied voltage for controlling each conversion means can be reduced, the gain can be changed more quickly than when there is only one conversion means.

[0022] For example, in a camera system according to one aspect of the present disclosure, the first conversion means may be a filter that changes the gain by attenuating the amount of incident light in accordance with an applied voltage, the second conversion means may be a filter that receives light that has passed through the first conversion means and changes the gain by attenuating the amount of incident light in accordance with an applied voltage, and the light receiving unit may convert the light that has passed through the second conversion means into an electrical signal as incident light.

[0023] This makes it possible to more precisely adjust the sensitivity to changes in brightness by, for example, simply adding another electronic ND filter to a normal imaging device that already has one electronic ND filter.

[0024] For example, in a camera system according to an aspect of the present disclosure, the first conversion means and the second conversion means may be filters having different types of ND (Neutral Density) mechanisms.

[0025] This makes it possible to take advantage of the advantages of different types of ND mechanisms to adjust the amount of incoming light.

[0026] For example, in a camera system according to one aspect of the present disclosure, the first conversion means is a filter that changes the gain by attenuating the amount of incident light in accordance with an applied voltage, and the light receiving unit has a second photoelectric conversion layer that converts light that has passed through the first conversion means into an electrical signal as incident light, and two second electrodes that sandwich the second photoelectric conversion layer, and the second photoelectric conversion layer, as the second conversion means, may change the gain by changing the quantum efficiency when converting incident light into an electrical signal in accordance with an applied voltage.

[0027] This allows the function of the electronic ND filter to be realized by the light receiving unit, making it possible to make the unit more compact than if two electronic ND filters were used.

[0028] For example, in a camera system according to one aspect of the present disclosure, the light receiving unit may have a first photoelectric conversion layer that converts incident light into an electrical signal and two first electrodes that sandwich the first photoelectric conversion layer, and a second photoelectric conversion layer that converts light that has passed through the first conversion means into an electrical signal as incident light and two second electrodes that sandwich the second photoelectric conversion layer, and the first photoelectric conversion layer, as the first conversion means, may change the gain by changing the quantum efficiency when converting incident light into an electrical signal in accordance with an applied voltage, and the second photoelectric conversion layer, as the second conversion means, may change the gain by changing the quantum efficiency when converting incident light into an electrical signal in accordance with an applied voltage.

[0029] In this way, by providing the first conversion means and the second conversion means in the light receiving section, the functions of two electronic ND filters can be realized by the light receiving section, which allows for a more compact size than when the electronic ND filters are provided separately from the light receiving section.

[0030] For example, in the camera system according to the aspect of the present disclosure, the applied voltage control unit may change a duty of a voltage pulse repeatedly applied to the second photoelectric conversion layer in accordance with the quantum efficiency.

[0031] This makes it possible to vary the gain by, for example, changing the pulse duty.

[0032] For example, a camera system according to one aspect of the present disclosure may further include an automatic / manual control unit that switches between an automatic mode in which the voltage applied by the applied voltage control unit is changed in response to the intensity of incident light, and a manual mode in which the voltage applied by the applied voltage control unit is changed in response to instructions from a user.

[0033] This allows the user to freely select a desired mode depending on the shooting conditions.

[0034] For example, a camera system according to an embodiment of the present disclosure may further include a white balance control unit that adjusts the white balance of the electrical signal converted by the light receiving unit in accordance with a voltage applied to the second photoelectric conversion layer.

[0035] This allows the white balance to be maintained even if the applied voltage is changed, making it possible to obtain a balanced image.

[0036] For example, in a camera system according to one embodiment of the present disclosure, the light receiving unit may further have a third electrode for applying a voltage to the second photoelectric conversion layer, and the applied voltage control unit may change the voltage applied to the third electrode depending on the quantum efficiency.

[0037] In this way, by providing the third electrode, the quantum efficiency can be adjusted simply by adjusting the voltage of the third electrode.

[0038] For example, in a camera system according to an aspect of the present disclosure, at least one of the first conversion means and the second conversion means may change a characteristic as a frequency filter in response to an applied voltage.

[0039] In this way, since the frequency filter is provided, light in a specific wavelength range can be selectively passed, and an image with a desired color tone can be obtained.

[0040] For example, a camera system according to one embodiment of the present disclosure may further include a display and a graphic interface unit that switches between displaying a first image that accepts instructions to change the gain continuously and a second image that accepts instructions to change the gain in a stepwise manner on the display.

[0041] This makes it possible to realize a desired user interface.

[0042] These comprehensive or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized by any combination of the system, the method, the integrated circuit, the computer program, and the recording medium.

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0044] However, more detailed explanations than necessary may be omitted. For example, detailed explanations of already well-known matters or duplicate explanations of substantially the same configurations may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following explanation are intended to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0045] In the drawings, elements that have substantially the same configuration, operation, and effect are denoted by the same reference numerals. In addition, all numerical values ​​described below are exemplified to specifically explain the present disclosure, and the present disclosure is not limited to the exemplified numerical values. Furthermore, the connection relationships between the components are exemplified to specifically explain the present disclosure, and the connection relationships that realize the functions of the present disclosure are not limited to these.

[0046] A camera system according to an embodiment of the present disclosure includes a light receiving unit that converts incident light into an electric signal, a first conversion means and a second conversion means that change a gain in a process from when the incident light is incident until when the incident light is converted into an electric signal by the light receiving unit according to an applied voltage, and an applied voltage control unit that applies a voltage to the first conversion means and the second conversion means, and the second conversion means is disposed at a position where the light that has passed through the first conversion means is incident. For example, the camera system is a camera that captures moving images and still images.

[0047] In the present disclosure, the light receiving section is an imaging element or an imaging device, and may be, for example, a stacked organic solid-state imaging device or a photodiode.

[0048] Moreover, the first conversion means and the second conversion means change the gain in the process from when the incident light is incident to when it is converted into an electric signal by the light receiving unit by changing the applied voltage. Here, the gain in the process from when the incident light is incident to when it is converted into an electric signal by the light receiving unit includes not only the conversion rate at which the incident light is converted into an electric signal but also the conversion rate from light to light, that is, the attenuation rate at which the amount of incident light is attenuated. For example, as an example of lowering the gain, when the camera system receives strong light such as direct sunlight, the amount of incident light can be attenuated to suppress the generation of an excessive voltage in the light receiving unit. As an example of changing the gain, the quantum efficiency at the time of converting the incident light into an electric signal can be changed to adjust the light sensitivity of the light receiving unit.

[0049] The camera system according to the present disclosure has the above-described configuration, and thus can adjust the sensitivity of the conversion means in more detail in response to changes in brightness.

[0050] Hereinafter, the first to fourth embodiments will be described as specific examples.

[0051] (First embodiment) An overview of the camera system according to the first embodiment of the present disclosure will be described below. Fig. 1 is a functional block diagram showing the configuration of a camera system 70A according to this embodiment.

[0052] In the camera system 70A according to this embodiment, the first conversion means 12A is a filter that changes the gain by attenuating the amount of incident light according to an applied voltage. The second conversion means 13A is a filter that receives the light that has passed through the first conversion means 12A and changes the gain by attenuating the amount of incident light according to an applied voltage. The light receiving unit 11A may convert the light that has passed through the second conversion means 13A into an electric signal as incident light.

[0053] As shown in FIG. 1, camera system 70A according to this embodiment includes an imaging unit 10A that captures an image of a subject, a graphic interface unit (hereinafter referred to as the graphic I / F unit) 30 that processes electrical signals output from the imaging unit 10A, a system control unit 20A that controls the operation of each component within the imaging unit 10A, a recording medium 40 that stores image data processed by the graphic I / F unit 30, a display 50 that displays images, and a user interface unit (hereinafter referred to as the user I / F unit) 60 that transmits input instructions from a user to the system control unit 20A.

[0054] The imaging unit 10A includes, in order from the side where light enters the imaging unit 10A, a lens 14, a mechanical shutter 15, a focus lens 16, a first conversion means 12A, a second conversion means 13A, and a light receiving unit 11A. In other words, the first conversion means 12A and the second conversion means 13A are provided separately from the light receiving unit 11A. The second conversion means 13A is disposed at a position where the light that has passed through the first conversion means 12A is incident.

[0055] The first conversion means 12A in this embodiment is a filter that changes the gain in the process from when the incident light is incident to when it is converted into an electrical signal by the light receiving unit 11A by attenuating the amount of incident light in accordance with the applied voltage, and is a so-called electronic ND filter.

[0056] The second conversion means 13A is a filter that receives light that has passed through the first conversion means 12A and attenuates the amount of incident light in accordance with an applied voltage, thereby changing the gain in the process from when the incident light is incident to when it is converted into an electrical signal by the light receiving unit 11A, and is a so-called electronic ND filter.

[0057] That is, camera system 70A according to this embodiment includes first conversion means (first electronic ND filter) 12A and second conversion means (second electronic ND filter) 13A whose sensitivity can be changed by an applied voltage.

[0058] Although FIG. 1 shows an example in which two electronic ND filters, the first electronic ND filter 12A and the second electronic ND filter 13A, three or more electronic ND filters may be provided.

[0059] In this embodiment, the light receiving unit 11A is a so-called imaging element that converts the light that has passed through the second conversion means 13A as incident light into an electrical signal. In this embodiment, the light receiving unit 11A may be, for example, a stacked solid-state imaging element using a photoelectric conversion film that performs photoelectric conversion according to the incident light. The photoelectric conversion film may include, for example, amorphous silicon. The light receiving unit 11A may be an imaging device such as a CCD (Charge Coupled Device) image sensor and a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0060] Furthermore, the camera system 70A according to this embodiment may include a display 50 and a graphic I / F unit 30 that switches between displaying a first image 60a that accepts instructions to continuously change the gain, and a second image 60b that accepts instructions to change the gain in stages on the display 50.

[0061] The display 50 is a display device that displays an image, and is, for example, a liquid crystal (LC) display or an organic electroluminescence (EL) display.

[0062] The graphic I / F unit 30 receives the digitally processed imaging data output from the light receiving unit 11A, compresses the imaging data using a predetermined compression method such as JPEG format, and stores the compressed imaging data in the recording medium 40. The recording medium 40 is a non-volatile memory, such as a flash memory.

[0063] Furthermore, the graphic I / F unit 30 reduces the digitally processed image data to an image size that matches the size of the display 50 and displays it on the display 50 .

[0064] The graphic I / F unit 30 also transmits the result of the feature amount calculated from the digitally processed imaging data output from the light receiving unit 11A to the system control unit 20A. Here, the feature amount is information indicating the characteristics of the image, and is, for example, a numerical value indicating the amount of focus deviation, exposure, or color tone of the image.

[0065] The system control unit 20A receives the feature amount of the imaging data calculated by the graphic I / F unit 30, and determines appropriate imaging conditions from the feature amount. Then, based on the determined imaging conditions, the system control unit 20A transmits a control signal to the imaging unit 10A.

[0066] The system control unit 20A in this embodiment includes a lens control unit 22, an exposure control unit 23, and an applied voltage control unit .

[0067] The lens control unit 22 controls the position to which the focus lens 16 is moved based on the amount of focus deviation calculated by the graphic I / F unit 30. In Fig. 1, the imaging unit 10A includes only one focus lens 16, but it may include multiple focus lenses 16. By including multiple focus lenses 16, the imaging unit 10A is less susceptible to the effects of aberration, and the focus can be adjusted more precisely.

[0068] Exposure control unit 23 controls the aperture value and shutter speed of mechanical shutter 15 based on the amount of exposure calculated by graphic I / F unit 30. Mechanical shutter 15 adjusts the amount of light (illuminance) incident on imaging unit 10A.

[0069] The applied voltage control unit 24 controls the applied voltage to the first conversion means 12A (for example, a variable transmittance neutral density filter) and the second conversion means 13A based on the feature amount of the imaging data calculated by the graphic I / F unit 30. This adjusts the light-to-light conversion rate in the first conversion means 12A and the second conversion means 13A, that is, the attenuation rate of the light amount.

[0070] The system control unit 20A may include an electronic shutter control unit that controls the start timing of charge accumulation in the light receiving unit 11A. Similarly, in each of the embodiments and modified examples described below, the system control unit may include an electronic shutter control unit.

[0071] The user interface (user I / F) unit 60 has an operation unit that accepts operations from the user and transmits operation signals from the user to the system control unit 20A. The user I / F unit 60 is, for example, a touch panel, a dial, or a push button. The touch panel is disposed on the display 50, detects a position on the touch panel touched by the user's finger, and transmits the position information to the system control unit 20A. The user can easily specify desired setting parameters by operating while checking display items such as setting parameters displayed on the display 50.

[0072] A specific example of the user I / F unit 60 will be described below.

[0073] As shown in Fig. 2, there are two types of means for the user to change the setting of the ND value: a touch type where the user specifies a parameter displayed on the display 50, and a mechanical type where the user specifies a parameter using a dial, push button, etc. There are also multi-step control types where the parameter can be adjusted in multiple steps, and stepless control types where the parameter can be adjusted continuously. Here, the parameter is the ND value.

[0074] In the touch-type stepless ND control shown in FIG. 2(a), a bar indicating the gradation of the ND value, which is a first image 60a, is displayed on the display 50. When a user traces the bar 60a indicating the gradation of the ND value displayed on the display 50 with a finger, the touch panel detects the position of the tracing finger. The touch panel transmits the detected finger position information to the system control unit 20A. This allows the user to instruct the system control unit 20A to change to a desired ND value. At this time, when the user traces the bar indicating the gradation of the ND value of the first image 60a with a finger, images corresponding to the transmittance touched by the finger are continuously displayed on the display 50.

[0075] In the touch-type multi-stage ND control shown in FIG. 2(b), icons indicating ND values ​​of each stage, which are the second image 60b, are displayed on the display 50. When the user touches with his / her finger the icon 60b indicating the multi-stage ND values ​​displayed on the display 50 to select it, the touch panel detects the position touched by the finger. The touch panel transmits the detected finger position information to the system control unit 20A. This allows the user to instruct the system control unit 20A to change to the desired ND value. At this time, when the user touches with his / her finger the icon indicating the ND value of each stage on the second image 60b to select it, an image corresponding to the ND value touched by the finger is displayed on the display 50.

[0076] In the mechanical multi-stage ND control shown in FIG. 2(c), the user can instruct the system control unit 20A to change to a desired ND value by turning a dial 60c arranged on the camera body.

[0077] In either case, the user can adjust the ND value while viewing the image displayed on the display 50, which allows for finer, faster, continuous or multi-step sensitivity adjustment. This makes it possible to prevent the display on the display 50 from suddenly changing due to a sudden change in exposure. This also makes it possible to reduce, for example, eye strain on the user.

[0078] Next, the ND mechanism in the camera system 70A according to this embodiment will be described in detail with reference to FIG. 3. FIG. 3 is a diagram for explaining the configuration of the first conversion means 12A and the second conversion means 13A in the camera system 70A according to the first embodiment. Note that FIG. 3 shows only the configuration necessary for explaining the ND mechanism. In this embodiment, the first conversion means 12A and the second conversion means 13A are both electronic ND filters. Hereinafter, in this embodiment, the first conversion means 12A and the second conversion means 13A are referred to as the first electronic ND filter 12A and the second electronic ND filter 13A, respectively.

[0079] 3, incident light enters the imaging unit 10A through the lens 14. The light that entered the imaging unit 10A passes through the first electronic ND filter 12A, and then passes through the second electronic ND filter 13A. As a result, the light that entered the imaging unit 10A is attenuated to a desired amount of light, and enters the light receiving unit 11A.

[0080] The first ND filter 12A has a pair of electrodes 120A and 122A, and a first ND filter layer 121A sandwiched between the pair of electrodes 120A and 122A. The second ND filter 13A has a pair of electrodes 130A and 132A, and a second ND filter layer 131A sandwiched between the pair of electrodes 130A and 132A.

[0081] In the camera system 70A according to this embodiment, the first electronic ND filter 12A and the second electronic ND filter 13A may be filters having different types of ND mechanisms.

[0082] For example, the first electronic ND filter 12A is a liquid crystal type electronic ND filter having a liquid crystal layer as the first ND filter layer 121A, and the second electronic ND filter 13A is a precipitation type electronic ND filter having a reactive material layer as the second ND filter layer 131A.

[0083] Next, a method for adjusting the sensitivity of the first electronic ND filter 12A and the second electronic ND filter 13A will be described. Fig. 4 is a diagram for explaining a method for adjusting the sensitivity of the first electronic ND filter 12A and the second electronic ND filter 13A in the camera system 70A according to this embodiment. The voltage power supply 80 in Fig. 4 is a power supply that applies a voltage to the electrodes of the filters, and the pulse duty voltage power supply 81 is a power supply that applies a pulse duty voltage to the electrodes of the filters.

[0084] Here, the first electronic ND filter 12A is a liquid crystal type electronic ND filter, and the second electronic ND filter 13A is a precipitation type electronic ND filter. These electronic ND filters change the light transmittance by adjusting the applied voltage with a voltage power supply 80. Since the liquid crystal type electronic ND filter contains a light-adjusting material in which the liquid crystal absorbs light, the degree of light adjustment, that is, the light transmittance, is changed by changing the tilt of the liquid crystal molecules by adjusting the applied voltage. In the precipitation type electronic ND filter, a reaction solution containing a reactant that undergoes a reversible oxidation-reduction reaction is filled inside a cell with electrodes provided on the inner surface, and the oxidation-reduction reaction of the reactant in the cell is controlled by adjusting the applied voltage. More specifically, by adjusting the applied voltage, the reactant silver chloride in the reaction solution undergoes an oxidation-reduction reaction, causing silver to precipitate or dissolve.

[0085] These liquid crystal type and precipitation type electronic ND filters can change the light transmittance uniformly, but are known to have a relatively slow response speed to changes in the amount of incident light. However, by using two electronic ND filters in combination as in the camera system 70A according to this embodiment, the amount of light attenuated by each electronic ND filter can be reduced compared to when one electronic ND filter is used. Therefore, in this embodiment, the response time until the incident light is attenuated to a desired amount of light can be reduced by about half compared to when only one electronic ND filter is provided. In other words, even in the case of a sudden change in the exposure amount of the subject, it is possible to shorten the response speed until the electronic ND filter changes to a light transmittance that attenuates the incident light to a desired amount of light.

[0086] 3 and 4 are merely examples, and the ND mechanism in the present disclosure may be composed of two or more electronic ND filters. Also, in the present embodiment, an example has been shown in which the individual electronic ND filters have different configurations, such as a liquid crystal type and a precipitation type, but the two or more electronic ND filters may all have the same configuration, or may be composed of any combination.

[0087] In this embodiment, a filter having characteristics other than the liquid crystal type and precipitation type electronic ND filters described above may be provided. For example, in the camera system 70A according to this embodiment, at least one of the first electronic ND filter 12A and the second electronic ND filter 13A may change its characteristics as a frequency filter according to the applied voltage. The frequency filter will be described below.

[0088] 5 is a schematic cross-sectional view of a frequency filter 300. The frequency filter 300 includes an electrode pair consisting of an anode 301 and a cathode 302, a filter layer 303 sandwiched between the electrode pair, and a spacer 304 that surrounds and seals the outer periphery of the filter layer while maintaining the distance between the electrode pair.

[0089] The filter layer 303 is disposed in a closed space surrounded by the electrode pair and the spacer 304, and contains a substance whose hue and color change when a voltage is applied to the electrode pair. In general, such a color change is called electrochromism, which is a reversible change in the hue and color of a substance caused by an electrochemical oxidation-reduction reaction. In other words, the color change is caused by a change in the oxidation-reduction state of the molecules and metal ions contained in the substance, which changes the absorption band of light. A substance that exhibits such electrochromism is called an electrochromic substance. Electrochromic substances will be described later.

[0090] When the constituent material of the electrolyte layer containing the electrochromic substance is liquid or gel-like, the constituent material may be sealed in a conductive film and placed between the electrodes, or may be directly injected into the space sealed by the electrode pair and the spacer. When the constituent material of the electrolyte layer containing the electrochromic substance is solid, such as powder, particles, film, layer, or plate, the constituent material may be molded by pressing, or may be molded by kneading with resin or the like. The constituent material may be molded into a non-fluid state, which is generally called a solid state. In this case, the spacer 304 that seals the filter layer 303 between the electrode pair may or may not be present.

[0091] As described above, the frequency filter 300 changes its hue and color by adjusting the voltage applied to the frequency filter 300. The mechanism by which the color change occurs is a reversible oxidation-reduction reaction of the electrochromic material in the electrode pair, and it is possible to switch between decolorization and coloring by adjusting the voltage applied to the electrode pair.

[0092] The anode 301 and the cathode 302 are preferably transparent electrodes. This allows light transmitted through the frequency filter 300 to be incident on the light receiving section 11A. The transparent electrodes may be any commonly used type. Specific materials and the definition of transparency will be described later in the description of the counter electrode in the second embodiment.

[0093] Next, electrochromic substances will be specifically described. Electrochromic substances exist in both organic and inorganic compounds. When the electrochromic substance is an organic compound, the molecules change into another substance or into a radical state by applying a voltage to the electrode pair, and the color changes. When the electrochromic substance is an inorganic compound, the molecules change into an oxidation-reduction reaction by applying a voltage to the electrode pair, and the color changes. For example, an example of an inorganic compound is pentacyanocarbonyl ferrate. Pentacyanocarbonyl ferrate turns blue when oxidized, but becomes colorless when reduced. Nickel oxide (NiOx) turns brown when oxidized, and becomes colorless when reduced. These inorganic compounds are of the oxidation coloring type. An example of an organic compound is heptyl viologen. Heptyl viologen turns purple when reduced, and becomes colorless when reduced. In other words, heptyl viologen is of the reduction coloring type.

[0094] Next, a description will be given of the frequency characteristics of the frequency filter 300. Fig. 6 is a graph illustrating the frequency characteristics of the frequency filter 300. In Fig. 6, the vertical axis represents the output, and the horizontal axis represents the wavelength of light transmitted through the filter.

[0095] Figure 6(a) is a graph showing the frequency characteristics of a high-pass filter that has high transmittance only for light in the short wavelength range, that is, light of high frequency. The high-pass filter uses pentacyanocarbonyl ferrate as the electrochromic material. As mentioned above, pentacyanocarbonyl ferrate turns blue when oxidized, and therefore increases the transmittance only for light in the short wavelength range that includes blue wavelengths, as shown in Figure 6(a).

[0096] Figure 6(b) is a graph showing the frequency characteristics of a low-pass filter that has high transmittance only for light in the long wavelength range, that is, low frequency light. The low-pass filter uses nickel oxide (NiOx) as the electrochromic material. As mentioned above, nickel oxide (NiOx) turns brown when oxidized, so it increases the transmittance only for light in the long wavelength range, such as the infrared and near-infrared ranges that include brown wavelengths.

[0097] Figure 6(c) is a graph showing the frequency characteristics of a bandpass filter that has high transmittance only for light with wavelengths in the mid-wavelength range. By combining electrochromic substances with the above-mentioned low-pass and high-pass characteristics, the bandpass filter reduces the transmittance of light with wavelengths in the short and long wavelength ranges and improves the transmittance of light with wavelengths in the mid-wavelength range, such as the visible light range. This absorbs light with wavelengths in the infrared and ultraviolet ranges and increases the transmittance only for light with wavelengths in the visible light range.

[0098] Figure 6(d) is a graph showing the frequency characteristics of a band elimination filter, which, unlike a band pass filter, has high transmittance only for light with wavelengths in the short and long wavelength ranges. Band elimination filters improve the transmittance of light in the short and long wavelength ranges and reduce the transmittance of light in the medium wavelength range such as the visible light range. This makes it possible to use the filter to transmit only light with wavelengths in the infrared and ultraviolet ranges.

[0099] In this way, by using a frequency filter as an electronic ND filter, it is possible to change the wavelength distribution (color temperature) of the light entering the light receiving section 11A much faster and easier than by attaching and detaching a color conversion filter to a lens.

[0100] (Modification 1 of the first embodiment) Next, a camera system according to Modification 1 of the first embodiment will be described. Fig. 7 is a functional block diagram showing the configuration of a camera system 70B according to this modification. Only the differences from camera system 70A according to the first embodiment will be described below.

[0101] The camera system 70B according to this modified example may further include an automatic / manual control unit 26 that switches between an automatic mode in which the voltage applied by the applied voltage control unit 24 is changed in response to the intensity of the incident light, and a manual mode in which the voltage applied by the applied voltage control unit 24 is changed in response to instructions from the user.

[0102] As shown in FIG. 7, a camera system 70B according to this modification differs from camera system 70A according to the first embodiment in that a system control unit 20B has an automatic / manual control unit 26.

[0103] The automatic / manual control unit 26 is a circuit that is connected to the first electronic ND filter 12A and the second electronic ND filter 13A, and transmits the control method, either automatic control or manual control, selected by the user I / F 60 to the first electronic ND filter 12A and the second electronic ND filter 13A.

[0104] The automatic / manual control unit 26 receives the feature amount of the imaging data calculated by the graphic I / F unit 30, determines appropriate imaging conditions from the feature amount, and performs automatic control to transmit a control signal to the imaging unit 10A under the determined imaging conditions. Furthermore, the automatic / manual control unit 26 also performs manual control in which the user checks the imaging data output from the graphic I / F unit 30 to the display 50, and transmits a control signal to the imaging unit 10A based on the imaging conditions input by the user to the user I / F unit 60.

[0105] For example, when the user selects automatic control of the electronic ND filter, an applied voltage and / or an applied voltage with a pulse duty ratio for controlling the recommended ND value selected by the automatic / manual control unit 26 is supplied to the first electronic ND filter 12A and the second electronic ND filter 13A. On the other hand, when the user selects manual control of the electronic ND filter, an applied voltage and / or an applied voltage with a pulse duty ratio corresponding to the ND value designated by the user via the user I / F unit 60 is supplied to the first electronic ND filter 12A and the second electronic ND filter 13A.

[0106] FIG. 8 is a table showing control patterns of the first electronic ND filter 12A and the second electronic ND filter 13A in a camera system 70B according to this modified example.

[0107] As in patterns 1, 3, 7, and 9 in Fig. 8, the user can select a control pattern in which both the first electronic ND filter 12A and the second electronic ND filter 13A are always fixed to either automatic control or manual control. Alternatively, as in pattern 5 in Fig. 8, the user can select a control pattern in which both the first electronic ND filter 12A and the second electronic ND filter 13A are always switchable between automatic control or manual control. Also, the user can select a control pattern in which either one of the first electronic ND filter 12A and the second electronic ND filter 13A is switchable between automatic control or manual control, and either the other of the first electronic ND filter 12A and the second electronic ND filter 13A is always fixed to manual control or automatic control.

[0108] Second embodiment Hereinafter, an overview of the camera system according to the second embodiment will be described. Fig. 9 is a functional block diagram showing the configuration of a camera system 70C according to this embodiment. In Fig. 9, different reference numerals are used only for configurations different from those of the camera system 70A according to the first embodiment.

[0109] In the camera system 70C according to this embodiment, the first conversion means 12C may be a filter that changes the gain by attenuating the amount of incident light according to the applied voltage. The light receiving unit 11C has a photoelectric conversion unit. The photoelectric conversion unit may include a photoelectric conversion layer that converts the light that has passed through the first conversion means 12C into an electrical signal, and two electrodes that sandwich the photoelectric conversion layer. The photoelectric conversion unit may change the gain as the second conversion means 13C by changing the quantum efficiency when converting the incident light into an electrical signal according to the applied voltage.

[0110] Hereinafter, only the configuration different from the camera system 70A according to the first embodiment will be described.

[0111] 9, a camera system 70C according to this embodiment differs from the first embodiment in that a photoelectric conversion unit in a light receiving unit 11C functions as a second conversion means 13C. In this case, a first conversion means 12C is disposed separately from the light receiving unit 11C.

[0112] Next, the ND mechanism in the camera system 70C according to this embodiment will be described in detail with reference to FIG. 10. FIG. 10 is a diagram for explaining the configuration of the first conversion means 12C and the second conversion means 13C in the camera system 70C according to this embodiment. Note that FIG. 10 shows only the configuration necessary for explaining the ND mechanism. In this embodiment, the first conversion means 12C is an electronic ND filter. Hereinafter, in this embodiment, the first conversion means 12C is referred to as the first electronic ND filter 12C. Note that, in this embodiment, an example in which the first electronic ND filter 12C is provided separately from the light receiving unit 11C is shown, but two or more electronic ND filters may be provided separately from the light receiving unit 11C. In addition, these electronic ND filters may be filters having different ND mechanisms.

[0113] As shown in FIG. 10, incident light is incident on the imaging unit 10C through the lens 14. The light incident on the imaging unit 10C passes through the first electronic ND filter 12C and then enters the second conversion means 13C in the light receiving unit 11C. Here, the first electronic ND filter 12C is, for example, a liquid crystal type electronic ND filter, and the second conversion means 13C is a photoelectric conversion unit in the light receiving unit 11C. The first electronic ND filter 12C has a pair of electrodes 120A and 122A and a first ND filter layer 121A sandwiched between the pair of electrodes 120A and 122A. The photoelectric conversion unit has a pair of electrodes 105 and 101 and a photoelectric conversion layer 104 sandwiched between the pair of electrodes 105 and 101, and converts the light incident on the photoelectric conversion unit into an electrical signal.

[0114] The graphic I / F unit 30 transmits the result of the feature amount calculated from the digitally processed imaging data output from the light receiving unit 11C to the system control unit 20A. The applied voltage control unit 24 transmits an instruction to the imaging unit 10C to adjust the applied voltage to the first electronic ND filter 12C and the photoelectric conversion unit which is the second conversion means 13C, based on the feature amount received by the system control unit 20A.

[0115] In this embodiment, the applied voltage control unit 24 adjusts the attenuation rate of light by controlling the applied voltage to the first electronic ND filter 12C, and adjusts the photosensitivity of the photoelectric conversion unit by controlling the applied voltage to the photoelectric conversion unit which is the second conversion means 13C. Note that the method of adjusting the photosensitivity of the photoelectric conversion unit will be described later with reference to FIG.

[0116] Camera system 70C according to this embodiment, having such a configuration, can adjust the sensitivity to changes in brightness more finely and quickly.

[0117] Next, the photoelectric conversion section will be described. The photoelectric conversion section has a pair of electrodes, and a photoelectric conversion layer 104 sandwiched between a counter electrode 105 and a pixel electrode 101, which are also a pair of electrodes.

[0118] The counter electrode 105 is typically a transparent electrode made of a transparent conductive material. The counter electrode 105 is disposed on the side of the photoelectric conversion section where light is incident. Therefore, light transmitted through the counter electrode 105 is incident on the photoelectric conversion layer 104. The light detected by the imaging section 10C is not limited to light within the wavelength range of visible light (e.g., 380 nm or more and 780 nm or less). In this specification, "transparent" means that at least a part of the light in the wavelength range to be detected is transmitted, and it is not essential that light is transmitted over the entire wavelength range of visible light. In this specification, electromagnetic waves in general, including infrared and ultraviolet rays, are expressed as "light" for convenience. The counter electrode 105 may be made of, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum-doped Transparent conducting oxides (TCOs) such as ITO (ITO zinc oxide), FTO (florine-doped tin oxide), SnO2, TiO2, and ZnO2 can be used. Figure 11 shows the relationship between the applied voltage and the output of the light receiving section in a photoelectric conversion film using ITO.

[0119] The photoelectric conversion layer 104 receives incident light and generates hole-electron pairs. One charge of the generated hole-electron pairs is captured by the pixel electrode 101 as a signal charge. The charge captured by the pixel electrode 101 is detected by a known signal detection circuit. The signal detection circuit may include an amplifier transistor that amplifies and outputs a signal corresponding to the signal charge. The gate of the amplifier transistor may be electrically connected to the pixel electrode 101. The photoelectric conversion layer 104 is typically formed from an organic semiconductor material.

[0120] Next, an overview of a method for making a photoelectric conversion unit function as an electronic ND filter will be described.

[0121] FIG. 11 is a graph showing the relationship between the voltage applied to the photoelectric conversion film and the output voltage from the light receiving unit. The vertical axis of FIG. 11 shows the normalized output voltage. Here, the normalized output voltage is a value normalized by setting the output voltage from the light receiving unit when the voltage applied to the photoelectric conversion unit is 10V as 1.0. Note that it is not necessary to use the output voltage when the applied voltage is 10V as the standard for normalization, and it may be changed as appropriate. In addition, since the threshold value may change depending on the calculation method and calculation range of the approximation line, the region where linearity is ensured may also differ from that shown in this figure.

[0122] From FIG. 11, it can be seen that the output voltage from the light receiving unit can be adjusted by adjusting the voltage applied to the photoelectric conversion unit. For example, from the graph shown in FIG. 11, the normalized output voltage corresponding to ND2, which reduces the amount of light output to half the amount of light incident on the filter, is 0.5, which is half of 1.0. Therefore, it can be seen that the ND function corresponding to ND2 can be realized in the photoelectric conversion unit by applying an applied voltage to adjust the normalized output voltage to 0.5 to the photoelectric conversion unit. In addition, the normalized output voltage corresponding to ND4, which reduces the amount of light output to one-quarter of the amount of light incident on the filter, is 0.25, which is one-quarter of 1.0, and the normalized output voltage corresponding to ND8, which reduces the amount of light output to one-eighth of the amount of light incident on the filter, is 0.125, which is one-eighth of 1.0. Similarly, for these NDs, the ND function can be realized in the photoelectric conversion unit by applying an applied voltage to the photoelectric conversion unit to adjust the normalized output voltage.

[0123] Therefore, by applying a voltage corresponding to a normalized output voltage equivalent to a desired ND function to the photoelectric conversion unit, it is possible to control the photoelectric conversion unit so that it also functions as an electronic ND filter. However, the relationship between the voltage applied to the photoelectric conversion unit and the output voltage from the light receiving unit is curved in the voltage range in which the photoelectric conversion unit exerts these ND functions, and linearity is not ensured over the entire range of the voltage applied to the photoelectric conversion unit.

[0124] For example, as shown in FIG. 11, there are regions where linearity is ensured between the voltage applied to the photoelectric conversion unit and the output voltage (here, the normalized output voltage) from the light receiving unit, and regions where linearity is not ensured. In a region where the applied voltage is greater than a threshold, that is, in a voltage region where linearity is ensured between the applied voltage and the normalized output voltage, a linear correlation is obtained between the applied voltage and the normalized output voltage, so that the light sensitivity of the photoelectric conversion unit can be easily adjusted by adjusting the magnitude of the voltage applied to the photoelectric conversion unit. On the other hand, in a region where the applied voltage is less than a threshold, that is, in a voltage region where linearity is not ensured between the applied voltage and the normalized output voltage, an applied voltage corresponding to a desired normalized output voltage is calculated from a function that represents the relationship between the applied voltage to the photoelectric conversion unit and the normalized output voltage. For this reason, it is necessary to store a function that represents the relationship between the applied voltage and the normalized output voltage in the camera system.

[0125] Therefore, when adjusting the light sensitivity of the photoelectric conversion unit to achieve the desired ND function, using an applied voltage and a standardized output voltage in a region where linearity is ensured in the relationship between the applied voltage and the standardized output voltage makes it easy to control the light sensitivity of the photoelectric conversion unit. This eliminates the need to store a function in the camera system, and allows the light sensitivity of the photoelectric conversion unit to be easily adjusted, thereby enabling the ND function to be realized by the photoelectric conversion unit.

[0126] Next, a procedure for controlling the light sensitivity of the photoelectric conversion unit as an electronic ND filter will be described. Fig. 12 is a flowchart showing a procedure for correcting the light sensitivity of the photoelectric conversion unit when the photoelectric conversion unit is used as an electronic ND filter.

[0127] In the camera system 70C according to this embodiment, the applied voltage control unit 24 may change the duty of the voltage pulse repeatedly applied to the photoelectric conversion unit in accordance with the quantum efficiency. In this embodiment, the photoelectric conversion unit is the second conversion means 13C.

[0128] As shown in Fig. 12, the applied voltage control unit 24 first determines whether or not the applied voltage corresponding to the output voltage of the photoelectric conversion unit, which corresponds to the desired ND value, is greater than a threshold value (see Fig. 11) (step S1). If the applied voltage is greater than the threshold value (YES in step S1), a linear correlation is obtained between the applied voltage to the photoelectric conversion unit and the output voltage, so the applied voltage corresponding to the desired ND value is determined (step S2) and the applied voltage to the photoelectric conversion unit is adjusted (step S3). This allows the photosensitivity of the photoelectric conversion unit to be changed to one corresponding to the desired ND value (step S4).

[0129] Next, a method for adjusting the photosensitivity of the photoelectric conversion unit in a voltage region where linearity is not ensured between the applied voltage and the normalized output voltage (NO in step S1) will be described.

[0130] The applied voltage control unit 24 first determines whether or not the applied voltage corresponding to the output voltage of the light receiving unit, which corresponds to the desired ND value, is greater than a threshold value (see FIG. 11), for example, 9V (step S1). If the applied voltage control unit 24 determines that the applied voltage is equal to or less than the threshold value of 9V (NO in step S1), it determines whether or not the ND value can be corrected by adjusting the applied voltage (step S5). The threshold value in step S5 is, for example, 7V. In step S5, it is determined whether or not the ND value can be corrected by adjusting the applied voltage depending on whether the applied voltage is greater than 7V.

[0131] Here, in the region near the threshold value of 9V or less in step S1, linearity may be obtained depending on the calculation method of the approximation line, and it is also possible to control the photosensitivity of the photoelectric conversion unit by determining the applied voltage corresponding to the desired ND value. For example, in the region of the applied voltage range of more than 7V and less than 9V in FIG. 11, linearity is considered to be obtained depending on the calculation method of the approximation line, compared to the region of 7V or less. In such a region, the applied voltage may be combined with a pulse duty, which will be described later, to adjust the photosensitivity to the desired ND value.

[0132] Therefore, if it is determined that the ND value can be corrected by adjusting the applied voltage (YES in step S5), a combination of the applied voltage and the pulse duty is determined (step S6). Next, the applied voltage is adjusted to the voltage determined in step S6 (step S7), and the pulse duty is adjusted (step S8). This allows the photoelectric conversion unit to be changed to a light sensitivity corresponding to the desired ND value (step S4).

[0133] On the other hand, if it is determined that the ND value cannot be corrected by adjusting the applied voltage (NO in step S5), that is, if the applied voltage corresponding to the output voltage corresponding to the desired ND value is 7V or less, linearity cannot be obtained between the applied voltage and the normalized output voltage. In this case, if the applied voltage corresponding to the output voltage corresponding to the desired ND value is applied to the photoelectric conversion unit as it is, the white balance will deteriorate as described later with reference to FIG. 24. Therefore, for example, a pulse duty that can realize the desired ND value is determined from the relationship between the applied voltage and the normalized output voltage in the region where the applied voltage is greater than the threshold value 9V in step S1, that is, the region where linearity is ensured (step S9). Then, the applied voltage is set to a predetermined value and adjusted to the determined pulse duty (step S10). The predetermined value may be a value greater than the threshold value 9V. This allows the photoelectric conversion unit to be changed to the light sensitivity corresponding to the desired ND value (step S4). By setting the applied voltage to a value greater than the threshold value 9V, the deterioration of the white balance can be suppressed.

[0134] In the present embodiment, the region below the threshold of 9V has been described as being divided into a region near the threshold (greater than 7V and less than 9V) and a region below the threshold (less than 7V), but the region below the threshold of 9V does not need to be divided finely as described above. For example, in a region where the applied voltage corresponding to the desired ND value is greater than the threshold of 9V, the photosensitivity may be adjusted by adjusting the applied voltage in steps S1 to S4, and in a region where the applied voltage corresponding to the desired ND value is less than the threshold of 9V, the photosensitivity may be adjusted by adjusting the pulse duty in steps S9 to S10. When adjusting the photosensitivity by adjusting the pulse duty, the magnitude of the applied voltage may be adjusted, or the magnitude of the applied voltage may be fixed to a predetermined value.

[0135] As described above, in Fig. 12, an example is described in which thresholds are provided for an area where linearity is ensured between the applied voltage to the photoelectric conversion unit and the normalized output voltage, and an area where linearity is not ensured. However, regardless of the threshold, a correlation is obtained between the control of the applied voltage by the voltage control method that controls the magnitude of the applied voltage, and the control of the applied voltage by the pulse duty control method that controls the applied voltage by making it a pulse duty. The correlation between them is described below.

[0136] Fig. 13 is an example of a timing chart for adjusting the light sensitivity by the voltage control method, and Fig. 14 is another example of a timing chart for adjusting the light sensitivity by the voltage control method.

[0137] 13 and 14, the vertical axis indicates the voltage applied to the photoelectric conversion unit, and the horizontal axis indicates the application time. Here, the change in the applied voltage for three arbitrary frames, N-1 frame, N frame, and N+1 frame, is illustrated. The same applies to Figs. 15 and 16 described later.

[0138] When the amount of incident light from the subject to the imaging unit 10D is stable, as shown in FIG. 13, the voltages applied to the photoelectric conversion unit in the N-1 frame, N frame, and N+1 frame are constant. Thus, when the amount of incident light is stable, there is no need to adjust the ND value for each frame, and it is possible to obtain a stable moving image even if the applied voltage is a constant value (V0).

[0139] When the amount of incident light from the subject to the imaging unit 10D fluctuates, that is, when the brightness of the subject repeats light and dark, as shown in FIG. 14, the applied voltage is adjusted for each of the N-1 frame, N frame, and N+1 frame. Thus, when the amount of incident light fluctuates, for example, the applied voltage is adjusted for each frame such that the applied voltage is V1 in the N-1 frame, V2 (>V1) in the N frame, and V3 (<V2) in the N+1 frame, and changed to an output voltage corresponding to a desired ND value. Thereby, since the photosensitivity of the photoelectric conversion unit can be appropriately adjusted according to the change in the amount of incident light, it becomes possible to obtain a moving image with a stable light amount. Note that in FIG. 14, V1, V2, and V3 [V] are applied voltages equal to or higher than the threshold voltage in FIG. 11.

[0140] Next, an example of adjusting the photosensitivity of the photoelectric conversion unit by the pulse duty control method will be described. FIG. 15 is an example of a timing chart for adjusting the photosensitivity by the pulse duty control method.

[0141] In the timing chart shown in FIG. 14, when V1 and V3 are values smaller than the threshold voltage in FIG. 11, the method of adjusting the photosensitivity by the pulse duty control method is also effective. Hereinafter, it is assumed that V1 and V3 are values smaller than the threshold voltage in FIG. 11.

[0142] In the timing chart shown in Fig. 15, the applied voltage value is kept constant (V2), and the pulse duty of the applied voltage is changed for each frame. At this time, the applied voltage in each frame shown in Fig. 15 has a correlation with the applied voltage in each frame shown in Fig. 14. Specifically, for example, as the duty of the pulse period T1 [s] of the applied voltage in the N-1 frame of Fig. 15, the High period is set to V1 / V2 and the Low period is set to (V2-V1) / V2. Thereby, the applied voltage corresponding to the applied voltage V1 in the N-1 frame of Fig. 14 can be reproduced. Similarly, as the pulse duty of the pulse period T2 [s] of the applied voltage in the N+1 frame of Fig. 15, the High period is set to V3 / V2 and the Low period is set to (V2-V3) / V2. Thereby, the applied voltage corresponding to the applied voltage V3 in the N+1 frame of Fig. 14 can be reproduced. The quantum efficiency of the photoelectric conversion unit when adjusting the ND value only with the applied voltage shown in Fig. 14 is the same as the quantum efficiency of the photoelectric conversion unit when adjusting the ND value only with the pulse duty shown in Fig. 15.

[0143] Fig. 16 is another example of a timing chart for adjusting the photosensitivity by the pulse duty control method. In the timing chart shown in Fig. 16, the applied voltage value and the pulse duty of the applied voltage are changed for each frame. At this time, the applied voltage in each frame shown in Fig. 16 has a correlation with the applied voltage in each frame shown in Fig. 14. Specifically, the applied voltage in the N-1 frame of Fig. 16 is V4 (<V2) [V], and as the duty of the pulse period T3 [s], the High period is set to V1 / V4 and the Low period is set to (V4-V1) / V4. Thereby, the applied voltage corresponding to the applied voltage V1 in the N-1 frame of Fig. 14 can be reproduced. Similarly, the applied voltage in the N+1 frame of Fig. 16 is V5 (<V2) [V], and as the pulse duty of the pulse period T4 [s], the High period is set to V3 / V5 and the Low period is set to (V5-V3) / V5. Thereby, the applied voltage corresponding to the applied voltage V3 in the N+1 frame of Fig. 14 can be reproduced. The quantum efficiency of the photoelectric conversion unit when adjusting the ND value only with the applied voltage shown in Fig. 14 is the same as the quantum efficiency of the photoelectric conversion unit when adjusting the ND value with the applied voltage and pulse duty shown in Fig. 16.

[0144] 15 and 16, V2, V4, and V5 [V] are applied voltages that ensure linearity equal to or greater than the threshold voltage in Fig. 11. Also, Figs. 13 to 16 show examples in which one frame is 1 / 60 [s]. However, in the present disclosure, the same effect can be expected for other frame rates, such as one frame being 1 / 120 [s] or 1 / 180 [s].

[0145] In this embodiment, the system control unit 20A may include a white balance control unit and a white balance table, as described later in Modification 3 of the second embodiment. Furthermore, the system control unit 20A may include an automatic / manual control unit.

[0146] 11 and 24 show an example in which lowering the applied voltage causes deterioration of the linearity between the applied voltage and the normalized output voltage and a loss of white balance. Conversely, the same effect as described above can be obtained for a photoelectric conversion unit in which an increase in the applied voltage causes deterioration of linearity or a loss of white balance. For example, for a photoelectric conversion unit in which an increase in the applied voltage causes deterioration of linearity, a constant voltage may be applied when adjusting the photosensitivity to a region of applied voltage with good linearity, and a pulse voltage may be applied when adjusting the photosensitivity to a region of applied voltage with poor linearity.

[0147] (Modification 1 of the second embodiment) Next, a camera system according to Modification 1 of the second embodiment will be described. Fig. 17 is a functional block diagram showing the configuration of a camera system 70D according to this modification. Only the differences from camera system 70C according to the second embodiment will be described below.

[0148] As shown in FIG. 17, a camera system 70D according to this modification differs from camera system 70C according to the second embodiment in that a system control unit 20D has a pulse duty control unit 29.

[0149] The pulse duty control unit 29 controls the light sensitivity of the photoelectric conversion unit based on the feature amount of the imaging data transmitted from the graphic I / F unit 30. In the second embodiment, the applied voltage control unit 24 controls the voltage applied to the photoelectric conversion unit, which is the first electronic ND filter 12C and second conversion means 13C arranged separately from the light receiving unit 11C. In this modification, the applied voltage control unit 24 controls the voltage applied to the first electronic ND filter 12C, and the pulse duty control unit 29 controls the voltage applied to the photoelectric conversion unit in the same manner as the control described above in the second embodiment.

[0150] A more detailed explanation will be given below with reference to Fig. 18. Fig. 18 is a diagram for explaining a method of adjusting the sensitivity of the first electronic ND filter 12C and the second conversion means 13C in the camera system 70D according to this modified example. In this diagram, only the configuration necessary for the explanation is shown.

[0151] 18, incident light enters the imaging unit 10C through the lens 14. The light that entered the imaging unit 10C passes through a first electronic ND filter 12C, and then enters a second conversion means 13C that is a photoelectric conversion unit in the light receiving unit 11C. Here, the first electronic ND filter 12C is, for example, a liquid crystal type electronic ND filter.

[0152] The voltage applied to the first electronic ND filter 12C by the voltage power supply 80 is controlled by the applied voltage control unit 24. This adjusts the attenuation rate of the light incident on the first electronic ND filter 12C.

[0153] The pulse duty control unit 29 controls the applied voltage and pulse duty of the power supply, which is a combination of a voltage power supply 80 and a pulse duty voltage power supply 81, for the photoelectric conversion unit, which is the second conversion means 13C. When the photoelectric conversion unit is made to function as an electronic ND filter, a voltage in a region where linearity is ensured between the voltage applied to the photoelectric conversion unit and the output voltage of the light receiving unit is used, so that the sensitivity can be adjusted quickly. At this time, although the available applied voltage value is limited, the applied voltage can be adjusted to a value equivalent to the desired ND value by making the voltage a pulse duty. This allows the light sensitivity of the photoelectric conversion unit to be adjusted more finely.

[0154] Depending on the ND value selected by the user I / F unit 60, the applied voltage control unit 24 may adjust the applied voltage to the first electronic ND filter 12C, and the pulse duty control unit 29 may adjust the applied voltage to the photoelectric conversion unit which is the second conversion means 13C, as necessary. In this way, when the photoelectric conversion unit is made to function as an electronic ND filter, the load on the applied voltage control unit 24 can be reduced by having the pulse duty control unit 29 control the applied voltage to the photoelectric conversion unit.

[0155] (Modification 2 of the second embodiment) The following describes an overview of a camera system according to the second modification of the second embodiment.

[0156] FIG. 19 is a diagram for explaining a light receiving section 11E in this modified example. As shown in FIG. 19, the light receiving section 11E in this embodiment has a plurality of pixels 100 and peripheral circuits formed on a semiconductor substrate. Each pixel 100 includes a photoelectric conversion section arranged above the semiconductor substrate, and is arranged in a matrix of m rows and n columns (m and n are integers equal to or greater than 2), for example, to form an imaging area 200. The peripheral circuits include a row scanning circuit 201, a signal processing circuit 202, a control unit 203, and an output circuit 204. The row scanning circuit 201 reads out and scans each pixel signal. The signal processing circuit 202 processes the read pixel signal. The control unit 203 generates a control signal for controlling the row scanning circuit 201 and the signal processing circuit 202. The output circuit 204 outputs a signal from the signal processing circuit.

[0157] The camera system of this embodiment is common to camera system 70C of the second embodiment and camera system 70G of the third embodiment (see Figure 25) in that the photoelectric conversion unit functions as an electronic ND filter, but the electrode structure of the photoelectric conversion unit is different.

[0158] 20 is a diagram for explaining the configuration of a photoelectric conversion unit in this modified example. Note that, for ease of explanation, only different configurations are shown in this diagram.

[0159] As shown in FIG. 20, the photoelectric conversion unit in this modification example differs from the second and third embodiments in that it has a third electrode 102 arranged so as to surround the periphery of a pixel electrode 101 in a pixel 100.

[0160] A method for adjusting the sensitivity of the photoelectric conversion unit in this modified example will be described below. Figures 21 and 22 are diagrams for explaining a method for adjusting the sensitivity of the photoelectric conversion unit in this modified example.

[0161] In a camera system according to variant 2 of the second embodiment, the light receiving unit 11E further has a third electrode 102 for applying a voltage to the photoelectric conversion layer 104, and the applied voltage control unit 24 (not shown) may change the voltage applied to the third electrode 102 depending on the required quantum efficiency.

[0162] 21, pixel 100 includes, from the light incident side, a counter electrode 105, a photoelectric conversion layer 104, a pixel electrode 101, a third electrode 102 arranged to surround the pixel electrode 101, an interlayer insulating layer 107 in which wiring is arranged, and a semiconductor substrate 108 in which a readout circuit is arranged. The third electrode 102 is also called an auxiliary electrode.

[0163] Here, the photoelectric conversion unit 12E is composed of a counter electrode 105, a photoelectric conversion layer 104, a pixel electrode 101, and a third electrode 102. The photosensitivity of the photoelectric conversion unit 12E is adjusted by the relationship between the strength of the electric field generated by the potential difference between the pixel electrode 101 and the counter electrode 105, and the strength of the electric field generated by the potential difference between the third electrode 102 and the counter electrode 105.

[0164] For example, when there is no potential difference between the third electrode 102 and the counter electrode 105, the area in which the third electrode 102 can capture the charge 106 is small (area 104A). Therefore, the charge 106 generated in the photoelectric conversion layer 104 near the third electrode 102 is not captured by the third electrode 102 and flows into the pixel electrode 101, thereby contributing to the photosensitivity of the photoelectric conversion unit 12E.

[0165] 22, when there is a potential difference between the third electrode 102 and the counter electrode 105, the area in which the third electrode 102 can capture the charge 106 expands as the potential difference increases (area 104B). Therefore, more of the charge 106 generated in the photoelectric conversion layer 104 near the third electrode 102 is captured compared to when the potential difference is small, and the photosensitivity of the photoelectric conversion unit 12E decreases.

[0166] Furthermore, the amount of trapped charge 106 is proportional to the strength of the electric field generated by the potential difference between the third electrode 102 and the counter electrode 105. That is, the photosensitivity of the photoelectric conversion unit 12E is adjusted by the voltage of the third electrode 102. For example, increasing the voltage of the third electrode 102 can improve the photosensitivity of the photoelectric conversion unit 12E, and decreasing the voltage of the third electrode 102 can decrease the photosensitivity of the photoelectric conversion unit 12E.

[0167] As described above, the camera system according to the second modification of the second embodiment can adjust the light sensitivity of the photoelectric conversion unit by adjusting the voltage applied to the third electrode 102. This optimizes the sensitivity of the light receiving unit 11E and expands the dynamic range.

[0168] (Modification 3 of the second embodiment) Next, a camera system according to Modification 3 of the second embodiment will be described. Fig. 23 is a functional block diagram showing the configuration of a camera system 70F according to this modification. Only the differences from camera system 70C according to the second embodiment will be described below.

[0169] Camera system 70F according to this modification may further include a white balance control unit 27 that adjusts the white balance of the electrical signal converted by light receiving unit 11C in accordance with the voltage applied to the photoelectric conversion unit. In this modification, the photoelectric conversion unit is a photoelectric conversion unit within light receiving unit 11C.

[0170] As shown in FIG. 23, camera system 70F of this modified example differs from camera system 70C of the second embodiment and camera system 70D of modified example 1 of the second embodiment in that the system control unit 20F has a white balance control unit 27 and a white balance table 28.

[0171] The white balance control is required when adjusting the light sensitivity by adjusting the voltage applied to the photoelectric conversion unit, for example, when the photoelectric conversion unit in the light receiving unit 11C is made to function as the second conversion means, as in this modified example.

[0172] The control of white balance will be specifically described below. Fig. 24 is a graph showing the relationship between the voltage applied to the photoelectric conversion film and the spectral characteristics of the wavelength.

[0173] As shown in FIG. 24, the higher the applied voltage to the photoelectric conversion unit, the higher the quantum efficiency of the photoelectric conversion unit. However, depending on the magnitude of the applied voltage to the photoelectric conversion unit, the quantum efficiency differs depending on the wavelength range of red (R), green (G), and blue (B) light. For example, in the graph in FIG. 24 where the applied voltage is the highest, the quantum efficiency in the B wavelength range is high, and the quantum efficiency in the green (G) wavelength range and the R wavelength range are approximately the same. In this case, the image obtained will have a bluish tone unless the white balance is adjusted. On the other hand, in the graph in FIG. 24 where the applied voltage is the lowest, the quantum efficiency in the red (R) wavelength range is high, and the quantum efficiency in the blue (B) wavelength range is low. In this case, the image obtained will have a reddish tone unless the white balance is adjusted.

[0174] As such, the quantum efficiency of the red (R), green (G), and blue (B) wavelength regions differs depending on the voltage applied to the photoelectric conversion unit, so it is necessary to adjust the white balance by adjusting the photosensitivity to light in these wavelength regions.

[0175] The white balance control unit 27 is a circuit for correcting the characteristics of the photoelectric conversion unit shown in FIG. 24, in which the spectral characteristics of the wavelength change depending on the magnitude of the voltage applied to the photoelectric conversion unit.

[0176] In white balance table 28, applied voltages and coefficients are stored as a table so that the RGB image signals can be multiplied by a coefficient so that the white balance remains constant even if the applied voltage changes. Alternatively, as another method, a function may be stored in white balance control unit 27 so that the RGB white balance remains constant according to the applied voltage to the photoelectric conversion unit that results in a desired transmittance, even if the applied voltage to the photoelectric conversion unit changes.

[0177] As a result, in this modified example, even if the voltage applied to the photoelectric conversion unit changes, the white balance can be adjusted by the function stored in the white balance control unit 27 or by making the white balance control unit 27 and the white balance table 28 function mutually. Therefore, the balance of the RGB pixel signals can be controlled, and the sensitivity of the light receiving unit 11A can be variably controlled, making it possible to capture a good image. In addition, since the optimum sensitivity adjustment can be made for each color, it is possible to capture a color image with good white balance.

[0178] Furthermore, the white balance table 28 does not need to be disposed in the system control unit 20F, and may be disposed elsewhere, such as in the recording medium 40. As described above in the first modified example of the second embodiment, when the photoelectric conversion unit in the light receiving unit 11C is caused to function as an electronic ND filter, a pulse duty control unit 29 (see FIG. 17) may be provided. By making the voltage applied to the photoelectric conversion unit a pulse duty, the light sensitivity of the photoelectric conversion unit can be adjusted more finely.

[0179] (Third embodiment) Hereinafter, an overview of the camera system according to the third embodiment will be described. Fig. 25 is a functional block diagram showing the configuration of a camera system 70G according to this embodiment. In Fig. 25, different reference numerals are used only for configurations different from the camera system 70A according to the first embodiment and the camera system 70C according to the second embodiment.

[0180] In the camera system 70G according to this embodiment, the light receiving unit 11G may have a first photoelectric conversion unit including a first photoelectric conversion layer that converts incident light into an electric signal and two first electrodes that sandwich the first photoelectric conversion layer. The light receiving unit 11G may also have a second photoelectric conversion unit including a second photoelectric conversion layer that converts light that has passed through the first conversion means 12G into an electric signal as incident light and two second electrodes that sandwich the second photoelectric conversion layer. The first photoelectric conversion unit may change the gain by changing the quantum efficiency when converting incident light into an electric signal as the first conversion means 12G in response to the applied voltage. The second photoelectric conversion unit may change the gain by changing the quantum efficiency when converting incident light into an electric signal as the second conversion means 13G in response to the applied voltage.

[0181] In this embodiment, an example is shown in which the first conversion means 12G and the second conversion means 13G are provided within the light receiving section 11G, but an electronic ND filter may be further provided separately from the light receiving section 11G.

[0182] Hereinafter, only the configuration that differs from the camera system 70A according to the first embodiment and the camera system 70C according to the second embodiment will be described.

[0183] As shown in FIG. 25, a camera system 70G according to this embodiment differs from the first and second embodiments in that a first conversion means 12G and a second conversion means 13G are located inside a light receiving section 11G.

[0184] Next, the ND mechanism in the camera system 70G according to the present embodiment will be described in detail with reference to Fig. 26. Fig. 26 is a diagram illustrating the configuration of the first conversion means 12G and the second conversion means 13G in the camera system 70G according to the present embodiment.

[0185] As shown in FIG. 26, incident light is incident on the imaging section 10G through the lens 14. The light incident on the imaging section 10G is incident on a photoelectric conversion section which is a first conversion means 12G in the light receiving section 11G. The first conversion means 12G has a first photoelectric conversion layer 1041 and two first electrodes 1051 and 1011 which sandwich the first photoelectric conversion layer 1041. The first photoelectric conversion layer 1041 converts the light incident on the first conversion means 12G into an electric signal. The incident light which has passed through the first conversion means 12G is incident on a photoelectric conversion section which is a second conversion means 13G. The second conversion means 13G has a second photoelectric conversion layer 1042 and two second electrodes 1052 and 1012 which sandwich the second photoelectric conversion layer 1042. The second photoelectric conversion layer 1042 converts the light incident on the second conversion means 13G into an electric signal.

[0186] In this embodiment, the quantum efficiency of these two photoelectric conversion units is changed to change the conversion rate from light to electricity. A more detailed explanation will be given below with reference to Fig. 27. Fig. 27 is a diagram for explaining a method of adjusting the sensitivity of the first conversion means 12G and the second conversion means 13G in this embodiment.

[0187] As shown in FIG. 27, the voltage applied by the voltage power supply 80 is controlled by the applied voltage control unit 24 to the photoelectric conversion unit, which is the first conversion means 12G. As in steps S1 to S3 described above in FIG. 12, the applied voltage control unit 24 adjusts the applied voltage to the photoelectric conversion unit to change the quantum efficiency of the photoelectric conversion unit. That is, the photosensitivity of the photoelectric conversion unit is adjusted by applying a voltage corresponding to a desired ND value to the photoelectric conversion unit. For example, when adjusting the photosensitivity using the voltage control method shown in FIG. 13 and FIG. 14, within a voltage region in which linearity is ensured between the applied voltage to the photoelectric conversion unit and the output voltage, the photosensitivity of the photoelectric conversion unit can be easily adjusted by adjusting the magnitude of the applied voltage to the photoelectric conversion unit. Note that, within a voltage region in which linearity is ensured, the photosensitivity of the photoelectric conversion unit can be adjusted more quickly by adjusting the magnitude of the applied voltage to the photoelectric conversion unit than by adjusting the applied voltage by pulse duty, which will be described later.

[0188] The applied voltage and pulse duty of the power source, which is a combination of the voltage power source 80 and the pulse duty voltage power source 81, are controlled by the applied voltage control unit 24 for the photoelectric conversion unit, which is the second conversion means 13G. As shown in steps S5 to S7 and steps S9 to S10 in FIG. 12, the applied voltage control unit 24 adjusts the applied voltage and pulse duty to the photoelectric conversion unit to change the quantum efficiency of the photoelectric conversion unit. At this time, since the voltage corresponding to the desired ND value exists in a voltage region where linearity is not ensured between the applied voltage to the photoelectric conversion unit and the output voltage from the light receiving unit, it is necessary to convert the voltage in the voltage region where linearity is ensured into a pulse duty. For example, when adjusting the photosensitivity using the pulse duty control method shown in FIG. 15 and FIG. 16, the output voltage can be adjusted to the desired ND value by converting the applied voltage in the region where linearity is ensured, for example, the applied voltage of 9V or more, into a pulse duty. This allows the photosensitivity of the photoelectric conversion unit to be adjusted to the desired ND value. By adjusting the voltage applied to the photoelectric conversion unit by making it a pulse duty, the light sensitivity of the photoelectric conversion unit can be adjusted more finely than in the case of adjusting the magnitude of the applied voltage.

[0189] Although the imaging device and camera system according to the present disclosure have been described above based on the embodiment and modified examples, the present disclosure is not limited to these embodiment and modified examples. As long as they do not deviate from the gist of the present disclosure, various modifications conceived by a person skilled in the art to the embodiment and modified examples, and other forms constructed by combining some of the components in the embodiment and modified examples are also included in the scope of the present disclosure.

[0190] In each of the above embodiments, a part of each component may be realized by executing a software program suitable for the component. The component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. [Industrial Applicability]

[0191] The imaging device and camera system of the present invention can be used in a variety of camera systems and sensor systems, such as digital still cameras, broadcast and commercial cameras, medical cameras, surveillance cameras, in-vehicle cameras, digital single-lens reflex cameras, and digital mirrorless single-lens cameras. [Explanation of symbols]

[0192] 10A, 10C, 10G Imaging unit 11A, 11C, 11E, 11G light receiving section 12A, 12C First conversion means (first electronic ND filter) 12E Photoelectric conversion unit 12G first conversion means 13A Second conversion means (second electronic ND filter) 13C Second conversion means 13G second conversion means 14 Lenses 15 Mechanical Shutter 16 Focus Lens 20A, 20B, 20D, 20F System control unit 22 Lens control unit 23 Exposure control section 24 Applied voltage control section 26 Automatic / Manual Control Unit 27 White balance control section 28 White Balance Table 29 Pulse duty control section 30 Graphic interface section (graphic I / F section) 40 Recording media 50 Display 60 User interface section (user I / F section) 60a 1st image 60b 2nd image 70A, 70B, 70C, 70D, 70F, 70G Camera System 80 Voltage Power Supply 81 Pulse duty voltage power supply 100 pixels 101 Pixel electrode (electrode) 102 3rd electrode 104 Photoelectric conversion layer 104A, 104B area 105 Counter electrode (electrode) 106 Charge 107 Interlayer insulation layer 108 Semiconductor Substrate 120A electrode 121A 1st ND filter layer 122A electrode 130A electrode 131A 2nd ND filter layer 132A electrode 200 Imaging area 201 Row scanning circuit 202 Signal Processing Circuit 203 Control Unit 204 Output circuit 1041 First photoelectric conversion layer 1042 Second photoelectric conversion layer 1051, 1011 1st electrode 1052, 1012 2nd electrode

Claims

1. a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on the side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween; a voltage supply circuit that applies a first voltage and a second voltage smaller than the first voltage between the first electrode and the second electrode; Control circuit Equipped with The control circuit includes: A length of time corresponding to a set decay rate for the first frame is determined; In the first frame, the voltage supply circuit is caused to apply the first voltage and the second voltage between the first electrode and the second electrode such that a length of an application time of the first voltage is the length of time. Camera system.

2. a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on the side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween; a voltage supply circuit that applies a first voltage and a second voltage smaller than the first voltage between the first electrode and the second electrode; Control circuit Equipped with The control circuit includes: determining a ratio corresponding to the decay rate set for the first frame; causing the voltage supply circuit to apply the first voltage and the second voltage between the first electrode and the second electrode in the first frame such that a ratio of application times of the first voltage in the first frame becomes the ratio; Camera system.

3. a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on the side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween; a voltage supply circuit that applies a first voltage and a second voltage smaller than the first voltage between the first electrode and the second electrode; Control circuit Equipped with The control circuit includes: A voltage value corresponding to the attenuation rate set for the first frame is obtained; In the first frame, the voltage supply circuit is caused to apply the first voltage and the second voltage having the voltage value between the first electrode and the second electrode. Camera system.

4. a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on the side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween; a voltage supply circuit that applies a first voltage and a second voltage smaller than the first voltage between the first electrode and the second electrode; Control circuit Equipped with The control circuit includes: A ratio to a reference voltage is obtained in response to the attenuation rate set for the first frame; causing the voltage supply circuit to apply the first voltage and the second voltage, each having a voltage value corresponding to the ratio, between the first electrode and the second electrode in the first frame; Camera system.

5. The attenuation rate corresponds to the ND filter number. A camera system according to any one of claims 1 to 4.

6. a user interface unit for receiving instructions from a user including the attenuation factor; A camera system according to any one of claims 1 to 4.

7. the user interface unit includes a display for displaying an image for receiving an instruction for continuously changing the attenuation rate; The camera system of claim 6.

8. the user interface unit includes a display for displaying an image for receiving an instruction for gradually changing the attenuation rate; The camera system of claim 6.

9. a detection circuit electrically connected to the first electrode for detecting the charge captured by the first electrode; A camera system according to any one of claims 1 to 8.

10. A method for driving a camera system including a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on a side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween, A length of time corresponding to a set decay rate for the first frame is determined; In the first frame, the first voltage and a second voltage smaller than the first voltage are applied between the first electrode and the second electrode so that a length of an application time of the first voltage is the length of time. Drive method.

11. A method for driving a camera system including a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on a side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween, determining a ratio corresponding to the decay rate set for the first frame; applying the first voltage and a second voltage smaller than the first voltage between the first electrode and the second electrode in the first frame such that a ratio of application times of the first voltage in the first frame becomes the ratio; Drive method.

12. A method for driving a camera system including a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on a side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween, A voltage value corresponding to the attenuation rate set for the first frame is obtained; In the first frame, a first voltage having the voltage value and a second voltage smaller than the first voltage are applied between the first electrode and the second electrode. Drive method.

13. A method for driving a camera system including a photoelectric conversion unit including a photoelectric conversion layer that converts incident light into electric charges, a first electrode located on a side of the photoelectric conversion layer where light is incident, and a second electrode facing the first electrode with the photoelectric conversion layer interposed therebetween, A ratio to a reference voltage is obtained in response to the attenuation rate set for the first frame; applying a first voltage having a voltage value corresponding to the ratio and a second voltage smaller than the first voltage between the first electrode and the second electrode in the first frame; Drive method.

14. The attenuation rate corresponds to the ND filter number. The driving method according to any one of claims 10 to 13.

Images