JP2006333439A - Imaging device, imaging unit, and imaging apparatus - Google Patents

Abstract

An object of the present invention is to provide an image sensor that expands a light amount range (dynamic range) in which a proper image can be acquired and has a shutter function and an aperture function.
On a pixel of an image sensor, a light shielding member that shields a photoelectric conversion unit and an actuator that drives the light shielding member are created using MEMS technology, and a light shielding amount for each pixel is controlled, thereby controlling a dynamic range. Realizes enlargement, shutter function, and aperture function.
[Selection] Figure 1

Description

  The present invention relates to an image pickup device, an image pickup unit, and an image pickup device, and more particularly to an image pickup device, an image pickup unit, and an image pickup device having a light shielding member that covers a photoelectric conversion unit on the image pickup device.

  In a solid-state imaging device such as a conventional CCD (Charge Coupled Device) type imaging device or a CMOS (Complementary Metal Oxide Semiconductor) type imaging device, incident light is converted into electric charges by a photoelectric conversion unit arranged in the pixel. Get a video signal. For example, a photo MOS gate or a photodiode is used as the photoelectric conversion unit. Both the CCD image sensor and the CMOS image sensor have a structure for accumulating charges generated by light incidence for a certain exposure time, and after that time, a signal corresponding to the accumulated charge amount. Is output.

  Since the amount of charge that can be accumulated is finite, when strong light is incident, the charge is saturated and an appropriate output signal cannot be obtained. In order to prevent this, if the light incidence is limited by optical means such as a filter or a diaphragm, the accumulated charge amount is too small for the weak light incidence, and the output signal is buried in the surrounding noise, so it is appropriate Can not obtain a stable output signal.

  That is, the solid-state imaging device has an incident light amount range (dynamic range) in which an appropriate output signal can be obtained. In general, the range is very narrow compared to the wide dynamic range of many imaging objects. Therefore, it is strongly desired to expand the dynamic range of the solid-state imaging device.

  As a prior art that attempted to expand the dynamic range from the solid-state imaging device or the signal processing side, the photodiode-generated charge is discarded from the storage means according to the amount of light to prevent saturation when a large amount of light is incident (for example, non- There is a technique in which accumulation and discharge are repeated during exposure and a signal amount is obtained from the number of times and the remaining accumulation amount (for example, see Non-Patent Document 2).

  On the other hand, filter means for changing light transmittance, such as a transmissive liquid crystal panel, is provided in front of the image pickup surface of the CCD image pickup device, and the light transmittance of the filter means is controlled according to the video signal level output from the image pickup device. Thus, a method for expanding the dynamic range by controlling light incidence itself has been proposed (see, for example, Patent Document 1).

Although not intended to expand the dynamic range, a light-shielding mask that shields part of the opening of each pixel is provided on the pixels of the image sensor, and the micro-actuator is used to switch the position of the light-shielding mask and capture multiple times. Thus, a method for increasing the resolution without increasing the number of pixels has been proposed (see, for example, Patent Document 2).
Fritz J.M. Kub and Gordon Wood Anderson, “Compressing Photodetectors for Long Optical Pulses Usage a Lateral Blowing Drain Structure,” IE Trav. 40, no. 10, pp. 1740-1744, 1993 David Stopa, Andre Simoni, Lorenzo Gonzo, Massimo Gottardi and Gian-Franco Dulla Beta 37, no. 12, pp. 1846-1852 2002 JP-A-6-70225 JP-A-8-163449

  However, in the method of Non-Patent Document 1, there is a possibility that a transistor used for controlling the amount of charge to be discarded becomes a noise generation source, and a good video signal may not be obtained. An A / D conversion circuit or the like is required for each pixel of the element, which causes a decrease in pixel aperture ratio and an increase in pixel size.

  In the method of Patent Document 1, a filter unit that changes light transmittance, such as a transmissive liquid crystal panel, is placed in front of a CCD image sensor, and the transmittance when not shielded is low (for example, a liquid crystal panel). In this case, the transmittance is at most 0.5 or less. Therefore, the contrast of the captured image is reduced, and the light is not completely shielded even when the light is shielded (for example, a liquid crystal panel has a transmittance of approximately 0.01 even when shielded). Therefore, there is a problem that a separate mechanical shutter is required at the time of charge transfer. In addition, since the characteristic change due to the temperature of a material such as a liquid crystal panel is large, the performance is further limited at low and high temperatures. Furthermore, since the response speed of a liquid crystal panel or the like is about several milliseconds, the switching speed between transmission and light shielding is slow, and it is not possible to appropriately limit the amount of light for a sudden change in the amount of light.

  In the method of Patent Document 2, the amount of light shielding is variably controlled only by increasing the resolution by switching the opening position in time series by changing the light shielding position relative to the opening of the pixel of the light shielding mask. The dynamic range cannot be expanded.

  The present invention has been made in view of the above circumstances, and expands a light amount range (hereinafter referred to as a dynamic range) in which an appropriate image can be acquired, and has an image pickup element, an image pickup unit, and an image pickup device having a shutter function and an aperture function. An object is to provide an apparatus.

  The object of the present invention can be achieved by the following constitution.

1. Pixels with photoelectric conversion parts are arranged in a two-dimensional shape,
A pixel column in which at least one side is arranged in the arrangement direction of a certain pixel, and a pixel column adjacent to the pixel column, in order to variably shield all or part of incident light to the photoelectric conversion unit; A light shielding member shorter than the distance of
An image pickup device comprising: a light shielding device including a light shielding driving unit for moving the position of the light shielding member on the photoelectric conversion unit.

  2. 2. The image pickup device according to 1, wherein the light shielding members are connected to each other at an end portion.

  3. The imaging device according to 1 or 2, further comprising an incident light amount detection unit that detects an incident light amount to the pixel.

  4). 3. The image sensor according to 1 or 2, further comprising: a light shielding amount storage unit that stores a light shielding amount that the light shielding device shields from light.

  5. 4. The image pickup device according to 3, wherein the light shielding device includes a light shielding amount storage unit that stores a light shielding amount that is shielded from light.

  6). The imaging device according to any one of 1 to 5, wherein the light shielding driving unit is configured to move the light shielding member with an electromagnetic force.

7.1 The imaging device according to any one of 1 to 6,
An imaging unit comprising: a light shielding control unit that variably controls a light shielding amount of light shielding by a light shielding device included in the imaging element.

8. The imaging device according to any one of items 1, 2, or 4,
Based on the photoelectric conversion output of the photoelectric conversion unit provided in the image sensor, a light shielding amount calculation unit having a first calculation mode for calculating the light shielding amount of the light shielding device provided in the image sensor;
An imaging unit, comprising: a light-blocking control unit that controls a light-blocking amount that the light-blocking device blocks light according to a calculation result of the light-blocking amount calculation unit having the first calculation mode.

An imaging device according to 9.4;
Based on the photoelectric conversion output of the photoelectric conversion unit included in the imaging device and the light shielding amount stored in the light shielding amount storage unit included in the imaging device, the light shielding amount for calculating the light shielding amount that the light shielding member included in the imaging device shields. A calculation unit;
An imaging unit, comprising: a light shielding control unit that controls a light shielding amount of the light shielding device according to a calculation result of the light shielding amount calculation unit.

10. The imaging device according to 10.3 or 5,
A light-blocking amount calculation unit having a fourth calculation mode for calculating a light-blocking amount of a light-blocking device included in the imaging device, based on the incident light amount detected by the incident light amount detection unit included in the imaging element;
An imaging unit comprising: a light shielding control unit that controls a light shielding amount of the light shielding device according to a calculation result of the light shielding amount calculation unit having the fourth calculation mode.

An imaging unit according to 11.7;
An imaging apparatus comprising: an imaging control unit that controls imaging by an imaging element included in the imaging unit.

An imaging unit according to 12.8 or 9,
An imaging control unit that controls imaging by an imaging element included in the imaging unit;
An output circuit that outputs a photoelectric conversion output of a photoelectric conversion unit included in the imaging device as a video signal;
The imaging control unit includes a light shielding amount calculation unit having a second calculation mode for calculating a light shielding amount of a light shielding device included in the imaging device based on a video signal output of the output circuit. apparatus.

An imaging unit according to 13.10.
An imaging control unit that controls imaging by an imaging element included in the imaging unit;
The imaging control unit includes a light-blocking amount calculation unit having a fifth calculation mode for calculating a light-blocking amount of a light-blocking device included in the imaging element based on an incident light amount output of an incident light amount detection unit included in the imaging unit. An imaging apparatus characterized by that.

The imaging unit according to any one of 14.8 to 10,
An imaging control unit that controls imaging by an imaging element included in the imaging unit;
The imaging apparatus, comprising: a light shielding amount calculation unit having a third calculation mode for calculating a light shielding amount of a light shielding device included in the imaging device based on a state of the imaging device.

  According to the present invention, an image sensor having a shutter function and a diaphragm function is expanded while a light-shielding member on a pixel is driven to variably control an incident area of light to the photoelectric conversion unit. An imaging unit and an imaging apparatus can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol shows the same or an equivalent part, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a schematic view of an image sensor according to an embodiment of the present invention, and is a front view schematically showing an example of an arrangement layout for each pixel of a light shielding member. FIG. 1A shows an example in which a light shielding member is provided for each pixel, FIG. 1B shows an example in which light shielding members of two pixels in the horizontal direction are provided integrally, and FIG. This is an example in which a four-pixel light shielding member for each pixel is provided integrally. Here, for the sake of simplicity, an example of a two-dimensional array of two pixels vertically and horizontally is shown, but the number of pixels is naturally not limited.

  In FIG. 1, an image sensor 100 is an element in which a plurality of pixels 110 are arranged. The pixel 110 has at least one photoelectric conversion unit 111 that converts incident light into an electrical signal. The photoelectric conversion output of the photoelectric conversion unit 111 is output to an output circuit (not shown), and is output as a video signal by the output circuit. The light shielding member 112 is disposed so as to variably shield all or part of the incident light to the photoelectric conversion unit 111.

  In the configuration of FIG. 1A, since the light shielding member 112 is provided for each pixel, the light shielding member for each pixel can be operated independently, and fine light shielding control is possible for each pixel. . In the configurations of FIGS. 1B and 1C, since the light shielding member 112 is provided across a plurality of pixels, the area required for the arrangement of the light shielding member 112 can be reduced with respect to the pixel area. Thus, the photoelectric conversion unit 111 can be enlarged, and the sensitivity can be improved without changing the pixel area. Further, in the configuration of FIG. 1C, for example, a pixel set (for example, four pixels R, G, G, and B in the case of a Bayer array) is shielded by one light shielding member, thereby forming a pixel. Since the shading rates of the two groups can be made the same, color balance correction in the subsequent stage can be simplified.

  As shown in FIG. 1A, the length a of at least one side of the light shielding member 112 is set to be shorter than the distance d between the columns of the pixels 110 (hereinafter referred to as the inter-column distance) d. ing. The same applies to FIGS. 1B and 1C. Here, the inter-column distance d will be described in detail with reference to FIG. FIG. 2 is a schematic diagram showing the arrangement of the pixels 110 for explaining the definition of the inter-column distance.

  In FIG. 2A, when the rectangular pixels 110 are arranged in the horizontal and vertical directions, for example, consider an array Hn of adjacent pixels in the nth column in the horizontal direction and an array Hn + 1 in the n + 1th column. The inter-column distance d is the distance between Hn and Hn + 1, that is, the pixel pitch Dh. The same idea may be applied to the vertical direction. On the other hand, in the imaging device having a structure (so-called honeycomb structure) in which hexagonal pixels 110 are densely arranged as shown in FIG. 2B, the horizontal and vertical directions may be the same as those in FIG. With regard to the diagonal direction, when considering the pixel array Hn and the pixel sequence Hn + 1 of the n + 1th column shown in FIG. 2B, the inter-column distance d is Hn and Hn + 1. The distance between them, ie, the diagonal pixel pitch Db. Thus, when there are a plurality of inter-column distances according to the arrangement of the pixels, the length a of at least one side of the light shielding member 112 is set to be shorter than at least one inter-column distance d.

  Next, a more specific configuration example of the light shielding device 117 will be described with reference to FIGS. 3, 4, and 5. The light shielding device 117 includes a light shielding member 112 and a light shielding driving unit 113 for moving the light shielding member 112 on the photoelectric conversion unit 111.

  FIG. 3 is a diagram showing a first embodiment of the light shielding device 117, and is a schematic diagram showing an example of a format in which a plurality of light shielding members 112a constituting the light shielding device 117 move in parallel with each other on the pixel 110. 3A is a diagram of two pixels viewed from the imaging surface side of the image sensor 100, and FIG. 3B is a cross-sectional view taken along the line AB of FIG. 3A. In this example, the first comb-like electrode 113a constituting the light-shielding driving unit 113 is provided on the surface of the pixel 110, and the second comb-like electrode 113b is provided on the light-shielding member 112a, so that the first comb-like electrode is provided. By the electrostatic force between the electrode 113a and the second comb-like electrode 113b, the light shielding members 112a are linearly moved in the vertical direction in FIG. Therefore, the light shielding amount of the photoelectric conversion unit 111 can be controlled by controlling the voltage applied between the first comb-shaped electrode 113a and the second comb-shaped electrode 113b.

  FIG. 4 is a diagram showing a second embodiment of the light shielding device 117, and shows an example of a format in which a plurality of light shielding members 112 b constituting the light shielding device 117 rotate around the rotation axis 114 on the pixel 110. 4A is a diagram of two pixels viewed from the imaging surface side of the image sensor 100, and FIG. 4B is a cross-sectional view of the CDE cross section of FIG. 4A. It is. In this example, the first comb-shaped electrode 113a constituting the light-shielding drive unit 113 is formed on the surface of the pixel 110, the second comb-shaped electrode 113b is disposed on the light-shielding member 112b, and concentrically around the rotation shaft 114. The light shielding member 112b is rotated about the rotation shaft 114 by the electrostatic force between the first comb-shaped electrode 113a and the second comb-shaped electrode 113b. Therefore, the light shielding amount of the photoelectric conversion unit 111 can be controlled by controlling the voltage applied between the first comb-shaped electrode 113a and the second comb-shaped electrode 113b.

  FIG. 5 is a diagram showing a third embodiment of the light shielding device 117, and the positions where the plurality of light shielding members 112 c constituting the light shielding device 117 cover the photoelectric conversion unit 111 around the fulcrum 115 and the photoelectric conversion unit 111. FIG. 5A is a schematic diagram illustrating an example of a form that rotates between positions away from each other. FIG. 5A is a diagram in which one pixel is viewed from the imaging surface side of the image sensor 100, and FIG. The figure seen from the G side side surface of 5 (a), FIG.5 (c) are sectional drawings of the FG cross section of Fig.5 (a). In this example, the first comb-like electrode 113a constituting the light-shielding driving unit 113 is provided on the surface of the pixel 110, and the second comb-like electrode 113b is provided on the end of the plate-like member 112c. Due to the electrostatic force between the comb-shaped electrode 113a and the second comb-shaped electrode 113b, the position between the position where the light-shielding member 112c is covered by the photoelectric conversion unit 111 around the fulcrum 115 and the position away from the photoelectric conversion unit 111. It is designed to rotate. Therefore, the light shielding amount of the photoelectric conversion unit 111 can be controlled by controlling the voltage applied between the first comb-shaped electrode 113a and the second comb-shaped electrode 113b.

  In the example described in FIGS. 3, 4, and 5, an electrostatic actuator using an electrode structure composed of comb-like electrodes is illustrated as the light shielding drive unit 113, but an electrostatic actuator having another electrode structure such as a parallel plate is illustrated. It may be. Further, a minute coil may be manufactured and the member may be moved by electromagnetic force, or a microactuator using a piezoelectric function as exemplified in Patent Document 2 described above may be used. The manufacture of these light-shielding drive units can be realized by using a general MEMS (Micro Electro-Mechanical System) manufacturing process called micromachine technology.

  The light shielding member 112 (112a, 112b, 112c, etc.) is small, about several microns in size, so that it can be driven at high speed, and is much faster than liquid crystal elements and electrochromic elements used as general optical switches. It is possible to block light. Further, the light shielding rate when completely shielded from light is extremely high as compared with liquid crystals and electrochromic elements. Therefore, in addition to expanding the dynamic range by controlling the amount of incident light, the amount of light is controlled regardless of the amount of incident light, and the amount of incident light is controlled in the same way as the aperture of the camera. It is possible to produce the same effect as the shutter. In particular, by simultaneously controlling the light shielding members 112 of all the pixels, the shutter can realize all pixel simultaneous exposure (so-called global shutter function), and can realize a very high shutter speed.

  Further, as described above, since the viscosity of liquid crystal and the like changes remarkably with temperature, the temperature range in which the light shielding performance can be guaranteed becomes very narrow. However, according to the light shielding device as in the present embodiment, the light shielding member is mechanically Since the position of the light-shielding device is changed by changing the position of the light-shielding device, a material whose characteristics are hardly changed by a temperature change such as an inorganic material can be selected.

  The energy for driving the light shielding device 117 is supplied through a connection line from a light shielding control unit 123 to a light shielding driving unit 113 described later.

  Next, the relationship between the light shielding of the photoelectric conversion unit 111 and the dynamic range will be described with reference to FIG. FIG. 6 is a schematic diagram showing the relationship between the light shielding of the photoelectric conversion unit 111 and the dynamic range, and is a graph of photoelectric conversion characteristics in which the horizontal axis represents the incident light quantity (B) and the vertical axis represents the imaging output (V).

  First, when the light is not shielded, the imaging output (V) maintains linearity in the range where the incident light quantity (B) is 0 (zero) to B1, as indicated by L1 in FIG. Saturates at (V = MAX). (Actually, in the case of a CCD or the like, there is a case where defects such as smear and blooming may occur when the luminance is higher than B1, but here it will be described as simply saturated for the sake of simplicity.) The dynamic range in this case is denoted as D1. To do.

  When 50% is shielded, that is, when the photoelectric conversion unit 111 is half shielded, the imaging output (V) is linear in the range of incident light quantity (B) from 0 (zero) to 2 × B1, as indicated by L2 in FIG. It retains the property and saturates at the maximum value at 2 × B1 or more. In this case, the dynamic range D2 = 2 × D1, and the dynamic range is doubled. Similarly, if the photoelectric conversion unit 111 is shielded by 75%, that is, 3/4, the dynamic range becomes D3 = 4 × D1 as indicated by L3 in FIG. 6, and the dynamic range is expanded four times.

  Therefore, for example, as shown in FIG. 1A, if a light shielding member 112 is provided for each pixel 110 of the image sensor 100, the light shielding amount can be adjusted for each pixel, and strong light is incident. A pixel has a large light shielding amount, and a pixel receiving weak light has a small light shielding amount, so that the dynamic range can be controlled for each pixel without sacrificing sensitivity.

  If the light shielding member 112 is configured as shown in FIGS. 1B and 1C, the dynamic range can be controlled with a plurality of pixels as one group. Therefore, for example, as described above, the dynamic range can be controlled for each set of pixels constituting the color, or the dynamic range can be controlled for each position on the screen, for each horizontal or vertical line. .

  Next, a fourth embodiment of the light shielding device 117 according to the present invention will be described with reference to FIG. FIG. 7 is a schematic diagram showing the fourth embodiment of the light shielding device 117 according to the present invention. The light shielding member 112a of the first embodiment shown in FIG. This is an example. In FIG. 7, the light shielding member 112d is connected to the light shielding member 112a of FIG. 3 one row at a time in the horizontal direction of the pixels, and is further connected in the vertical direction outside the area where the pixels are arranged on the image sensor 100. It is integrated.

  A second comb-shaped electrode 113b constituting the light shielding driving unit 113 is provided on the back surface of the connecting portion 112e in the vertical direction of the light shielding member 112d. A first comb-shaped electrode 113a is provided on the surface of the portion facing the comb-shaped electrode 113b, and a voltage applied between the first comb-shaped electrode 113a and the second comb-shaped electrode 113b. By controlling this, it is possible to simultaneously move the light shielding members 112d of all the pixels and simultaneously change the light shielding area of all the pixels. Thereby, not only the exposure amount control of the pixel 110 but also a shutter function capable of simultaneous exposure of all the pixels of the image sensor 100 can be realized.

  According to the present embodiment, the amount of movement of the light shielding member 112d is very small, about the size of the photoelectric conversion unit 111, so that the operation can be speeded up, and the shutter is much faster than the conventional mechanical shutter. Can be realized. Furthermore, unlike the conventional focal plane shutter, the exposure timing does not differ depending on the position on the image sensor, and all pixels can be exposed simultaneously, so that no image flows even for a subject moving at high speed.

  Also, in the method of expanding the dynamic range, which is one of the conventionally known dynamic range expansion methods, and the image is synthesized by cutting out the appropriate exposure portion from a plurality of images having different exposure times, it is very short by using this embodiment. Since the exposure time can be realized, the image sensor is less likely to be saturated even in a very bright portion, and the dynamic range can be significantly widened compared to the conventional case.

  In the example shown in FIG. 7, the light shielding member 112 d is connected to the light shielding member 112 a of FIG. 3 in a horizontal direction of the pixels one by one, and further in the vertical direction outside the area where the pixels are arranged on the image sensor 100. However, the present invention is not limited to this, and may be connected one column at a time in the vertical column direction and horizontally connected outside the pixel region.

  In the example shown in FIG. 7, the light shielding member 112d is connected in the vertical direction only on one side (the right side in the figure), but a connecting part is also provided on the left side in the figure, and the first and A second comb-like electrode may be provided. In this case, although there is a drawback that the area of the portion where the connecting portion is disposed is increased, the driving force of the light shielding member 112d is increased and the mechanical strength is increased, so that a faster shutter function can be realized.

  Next, a first embodiment of drive control of the light shielding device 117 will be described with reference to FIGS.

  FIG. 8 is a circuit block diagram when focusing on one pixel 110 of the image sensor 100, and FIG. 9 is a flowchart showing an operation flow of the circuit block shown in FIG.

  First, in FIG. 8, the pixel 110 includes a photoelectric conversion unit 111, a light shielding device 117 including a light shielding member 112 and a light shielding driving unit 113, and includes a plurality of pixels 110, a light shielding amount calculation unit 121 described later, and light shielding control. The imaging device 100 is configured by peripheral circuits including the unit 123 and the output circuit 126.

  The photoelectric conversion output 116 of the photoelectric conversion unit 111 is input to the light shielding amount calculation unit 121, and the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121 is input to the light shielding control unit 123. The light shielding drive unit 113 is driven by 124 and the light shielding amount of the light shielding member 112 is controlled. The operation of the light shielding amount calculation unit 121 is controlled by a light shielding amount calculation unit control signal 125 from an external circuit (not shown). On the other hand, the photoelectric conversion output 116 of the photoelectric conversion unit 111 and the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121 are also input to the output circuit 126, and the output circuit 126 performs predetermined signals such as signal amplification and noise removal. After the processing, the video signal 127 is output to an external circuit (not shown).

  Further, as indicated by a broken line in FIG. 8, a light shielding amount storage unit 128 that stores a light shielding amount for each pixel 110 may be additionally provided. The light shielding amount storage unit 128 includes, for example, a capacitor provided in the pixel 110, and is connected in parallel to, for example, the first comb-shaped electrode 113a and the second comb-shaped electrode 113b in the example illustrated in FIG. Thus, the electrostatic force between the first comb-shaped electrode 113a and the second comb-shaped electrode 113b is more stably maintained for a long time. As a result, even when the exposure time is long, that is, when the time from the control of the light shielding amount of the light shielding member 112 to the end of photographing is long, the light shielding amount of the light shielding member 112 can be kept more stable and constant. When a plurality of pixels are simultaneously shielded by one light shielding member 112, the light shielding amount storage unit 128 may be provided at a ratio of one for each of the plurality of pixels.

  Next, the flow of drive control of the light shielding device 117 in the image sensor 100 shown in FIG. 8 will be described with reference to FIG. FIG. 9 is a flowchart showing a flow of drive control of the light shielding device 117 in one imaging operation in the image sensor 100.

  In step S101, it is determined whether or not the first mode is selected for the control of the light shielding device 117. The first mode is a mode for “enlarging the dynamic range”. If the first mode is selected (step 101; YES), the process of step S102 is executed. If the first mode is not selected (step 101; NO), the second mode is selected in step S111. Is selected and the process is executed. The second mode is, for example, a “shutter operation” mode.

  In step S102, the light shielding drive unit 113 is driven to set the light shielding amount of the light shielding member 112 to a predetermined value, and in step S103, the first time of the photoelectric conversion unit 111 is shorter than the time required for original photographing. Exposure is performed, and the process proceeds to step S104.

  In step S111, an exposure calculation for adjusting the exposure time and aperture value is performed by an external circuit (not shown), and a control signal 125 corresponding to an appropriate aperture amount and shutter speed is output to the exposure amount calculation unit 121, and the process proceeds to step S104. move on.

  In step S104, based on the photoelectric conversion output 116 of the photoelectric conversion unit 111 by the first exposure in step S103 or the control signal 125 output in step S111, the light shielding amount calculation unit 121 calculates the light shielding amount at the time of shooting, In step S <b> 105, based on the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121, the light shielding driving unit 113 is driven by the light shielding control output 124 of the light shielding control unit 123 to control the light shielding amount of the light shielding member 112. In step S106, shooting is performed. Thereafter, the photoelectric conversion output 116 of the photoelectric conversion unit 111 is transmitted to the output circuit 126. After predetermined signal processing such as signal amplification and noise removal is performed in the output circuit 126 in step S107, the video signal is output in step S108. 127 is output to an external circuit (not shown).

  When the light shielding amount storage unit 128 is additionally provided in FIG. 8, the light shielding amount storage value 161 of the light shielding amount storage unit 128 that stores the current light shielding amount of the light shielding member 112 is set as the light shielding as shown by the broken line in FIG. By inputting to the amount calculation unit 121, the light shielding amount calculation unit 121 can calculate the light shielding amount control value 122 based on the photoelectric conversion output 116 and the light shielding amount storage value 161. As a result, the first exposure is not necessary, and the operations in steps S102 and S103 can be omitted, so that a higher speed operation is possible.

  In the present embodiment, for example, as in the case where an FT (Frame Transfer) type CCD is used as the main image sensor, the photoelectric conversion output 116 of the photoelectric conversion unit 111 is transmitted to the output circuit 126 after the photographing in step S105. In some cases, it is desired to stop the light incident on the photoelectric conversion unit 111 until the time until This is because the FT-type CCD uses the photoelectric conversion unit 111 itself as a transfer path for the photoelectric conversion output 116, and therefore the photoelectric conversion output 116 itself changes when light enters during transfer. In such a case, a shutter device may be provided separately from the main imaging unit, or, as described above, the light shielding device 117 of the main imaging unit so as to be completely shielded simultaneously with the end of photographing in step S106. May be used as a shutter. In the former case, the control of the light shielding device 117 is simplified, and in the latter case, a separate shutter is unnecessary.

  When calculating the light shielding amount at the time of photographing in step S104, as described with reference to FIG. 6, the pixel determined that the incident light amount is small (that is, dark) from the first exposure result has a small light shielding amount. If pixels that are judged to have a lot of light (that is, bright) are made to have a large amount of light shielding, the pixels in the dark part will have sufficient sensitivity, and the pixels in the very bright part will not be saturated easily. The dynamic range expansion that is the object of the present invention is achieved.

  Note that the light shielding amount calculation unit control signal 125 input to the light shielding amount calculation unit 121 is mainly a signal for controlling the calculation timing and the like, but information about the pixel 110 that is the target of the light shielding amount calculation, for example, the image sensor 100. Information such as the position on the chip and the filter color may be included. If the light shielding amount is calculated based on these pieces of information, partial exposure control and color balance correction processing on the photographing screen can be simplified.

  In the present embodiment, in the second and subsequent shooting operations, the process of step S102 can be omitted, and the first exposure can be performed with the light shielding amount at the previous shooting. In this case, since it is not necessary to control the light shielding member 112 twice, the speed can be further increased.

  Next, a second embodiment of drive control of the light shielding device 117 will be described with reference to FIG. 10, FIG. 11, and FIG.

  FIG. 10 is a circuit block diagram when focusing on one pixel 110 of the image sensor 100. FIG. 11 is a flowchart showing an operation flow of the circuit block shown in FIG. 10, and FIG. 12 is shown in FIG. 6 is a timing chart showing the operation timing of the flowchart.

  First, in FIG. 10, the pixel 110 is provided with an incident light amount detection unit 131 that detects the incident light amount. The incident light amount detection unit 131 may be disposed at a position that is not shielded by the light shielding member 112, and may be provided on the pixel 110 or may be provided on the light shielding member 112. The incident light amount output 132 of the incident light amount detector 131 is input to the light shielding amount calculator 121.

  Further, as described with reference to FIG. 8, a light shielding amount storage unit 128 that stores a light shielding amount indicated by a broken line in FIG. 10 may be additionally provided for each pixel 110. This effect is also the same as described above with reference to FIG.

  Next, in the flowchart of FIG. 11, in step S101, it is determined whether or not the first mode is selected. If the first mode is selected (step 101; YES), the process of step S121 is executed. If the first mode is not selected (step 101; NO), the second mode is set in step S111. Once selected, the process is executed.

  In step S121, the incident light amount is detected by exposure of the incident light amount detection unit 131. In step S122, the light shielding amount calculation unit 121 calculates the light shielding amount at the time of photographing based on the incident light amount output 132 of the incident light amount detection unit 131. In step S123, based on the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121, the light shielding driving unit 113 is driven by the light shielding control output 124 of the light shielding control unit 123 to control the light shielding amount of the light shielding member 112. I do. The subsequent processing is the same as that shown in FIG.

  Next, the drive control timing of the light shielding device 117 will be described with reference to FIG. In step S <b> 121, the incident light amount detection unit 131 detects the incident light amount, and transmits an incident light amount output 132 to the light shielding amount calculation unit 121. In step S 122, the light shielding amount calculation unit 121 calculates a light shielding amount based on the incident light amount output 132, and transmits the light shielding amount control value 122 to the light shielding control unit 123 and the output circuit 126. In step S123, the light shielding amount control unit 123 drives the light shielding driving unit 113 with the light shielding control output 124 based on the light shielding amount control value 122, and moves the light shielding member 112 to the light shielding position.

  On the other hand, the photoelectric conversion unit 111 performs imaging in step S <b> 106 and transmits the photoelectric conversion output 116 to the output circuit 126. In step S107, the output circuit 126 performs predetermined signal processing such as signal amplification and noise removal according to the light shielding amount on the photoelectric conversion output 116, and outputs the video signal 127 in step S108.

  In the present embodiment, during one shooting operation (from the start of step S106 to the completion of step S108), the calculation of the light shielding amount for the next shooting and the light shielding member control are executed in parallel. . Hereinafter, as described above, the light-shielding amount calculation operation using the incident light amount detection unit 131 and the imaging operation using the first photoelectric conversion unit 111 are repeated in parallel.

  In the flow of drive control of the light-shielding device 117 in the first embodiment shown in FIG. 9, the imaging operation in the photoelectric conversion unit 111 is required twice, that is, the first exposure in step S103 and the imaging in step S106. Although it takes time to obtain the video signal 127, in the second embodiment, the imaging operation in the photoelectric conversion unit 111 is only performed in step 106, so the time until the video signal 127 is obtained is shortened. it can.

  Similarly to the description of FIG. 9 described above, also in this example, a pixel determined to have a small amount of incident light (that is, dark) has a small amount of light shielding, and a pixel determined to have a large amount of incident light (that is, bright) has a light shielding amount. If the number of pixels is increased, sufficient sensitivity can be obtained for dark pixels, and the photoelectric conversion unit 111 is less likely to be saturated even for very bright pixels, so that the dynamic range expansion that is the object of the present invention is achieved. .

  Next, a first embodiment of the imaging unit according to the present invention will be described with reference to FIGS. 13 and 14 by taking an imaging apparatus as an example.

  FIG. 13 is a circuit block diagram of the imaging apparatus 1 when attention is paid to one pixel 110 of the imaging element 100, and includes the imaging unit 10 and an imaging apparatus control unit 140 that functions as an imaging control unit.

  Each of the pixels 110 includes a photoelectric conversion unit 111 and a light shielding device 117 including a light shielding member 112 and a light shielding driving unit 113, and the imaging device 100 includes a plurality of pixels 110 and a peripheral circuit (not shown). The imaging unit 10 includes the imaging element 100 and peripheral circuits including a light shielding amount calculation unit 121, a light shielding control unit 123, and an output circuit 126, which will be described later.

  Here, the peripheral circuit including the light shielding amount calculation unit 121, the light shielding control unit 123, and the output circuit 126 will be described as being separate from the image sensor 100. However, as a matter of course, these are as shown in FIG. 100 may be included. For example, in the case of a CMOS image sensor, it is not particularly difficult to integrate them. When the peripheral circuits are integrated, the image pickup device itself operates as an image pickup unit.

  The photoelectric conversion output 116 of the photoelectric conversion unit 111 is input to the light shielding amount calculation unit 121, and the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121 is input to the light shielding control unit 123. The light shielding drive unit 113 is driven by 124 and the light shielding amount of the light shielding member 112 is controlled. The operation of the light shielding amount calculation unit 121 is controlled by a light shielding amount calculation unit control signal 125 of the imaging device control unit 140.

  On the other hand, the photoelectric conversion output 116 of the photoelectric conversion unit 111 and the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121 are also input to the output circuit 126, and the output circuit 126 performs signal amplification and noise according to the light shielding amount. After performing predetermined signal processing such as removal, the video signal 127 is input to the CPU 142 via the interface 143 of the imaging device control unit 140 outside the imaging unit 10. The CPU 142 performs predetermined image processing on the video signal 127 according to a program stored in the storage device 146 such as a flash memory or a hard disk, and displays the image signal 127 on the display 144 or stores it in the storage device 146.

  Further, as indicated by a broken line in FIG. 13, a light shielding amount storage unit 128 that stores a light shielding amount for each pixel 110 may be additionally provided. The light shielding amount storage unit 128 includes, for example, a capacitor provided in the pixel 110 and is connected in parallel to, for example, the first comb-shaped electrode 113a and the second comb-shaped electrode 113b in the example illustrated in FIG. Thus, the electrostatic force between the first comb-shaped electrode 113a and the second comb-shaped electrode 113b is more stably maintained for a long time. As a result, even when the exposure time is long, that is, when the time from the control of the light shielding amount of the light shielding member 112 to the end of photographing is long, the light shielding amount of the light shielding member 112 can be kept more stable and constant. When a plurality of pixels are simultaneously shielded by one light shielding member 112, the light shielding amount storage unit 128 may be provided at a ratio of one for each of the plurality of pixels.

  As for the control of the light shielding device 117, the following three types of modes can be executed. The first and second modes are modes for expanding the dynamic range.

  In the first mode, the light shielding amount calculation unit 121 on the imaging unit 10 calculates the light shielding amount based on the photoelectric conversion output 116 (first calculation mode), and the calculated light shielding amount control value 122 is the light shielding control. The light shielding driving unit 113 is driven by the light shielding control output 124 of the light shielding control unit 123 and the light shielding amount of the light shielding member 112 is controlled.

  In the second mode, the CPU 142 calculates the light shielding amount based on the video signal 127 input to the interface 143 (second calculation mode), and the calculated second light shielding amount control value 152 sets the interface 143. The light shielding drive unit 113 is driven by the light shielding control output 124 of the light shielding control unit 123, and the light shielding amount of the light shielding member 112 is controlled. That is, the CPU 142 functions as a light shielding amount calculation unit.

  In the first and second modes, a pixel judged to have a small amount of incident light (that is, dark) has a small amount of light shielding, and a pixel judged to have a large amount of incident light (that is, bright) has a large amount of light blocked. For example, sufficient sensitivity can be obtained for pixels in dark portions, and the photoelectric conversion unit 111 is less likely to be saturated in pixels in very bright portions, so that the dynamic range expansion that is the object of the present invention is achieved.

  In the first mode, only by receiving the light shielding amount calculation unit control signal 125 from the imaging device control unit 140, the light shielding amount calculation completed within the imaging unit 10 can be performed without depending on the CPU 142. The dynamic range can be expanded without increasing the load on the entire system.

  Furthermore, in the second mode, by using the CPU 142 as the light shielding amount calculation unit, it is possible to perform more advanced light shielding amount calculation than the light shielding amount calculation unit 121 on the imaging unit 10 or to make the light shielding amount calculation programmable. It becomes possible.

  In the third mode, the CPU 142 calculates the second light shielding amount control value 152 according to the program stored in the storage device 146 (third calculation mode) and inputs the second light shielding amount control value 152 to the light shielding control unit 123 via the interface 143.

  In the third mode, the amount of light shielded is controlled regardless of the amount of incident light, and the amount of incident light is controlled in the same way as the diaphragm of the camera, or the same effect as the shutter is obtained by controlling the light to be completely shielded after shooting. Is possible. In particular, the shutter can simultaneously control the light shielding members 112 of all the pixels to realize simultaneous exposure of all the pixels (so-called global shutter function). Further, by adjusting the light shielding amount for each pixel in accordance with the photographing lens to be used, it is possible to correct a decrease in the amount of peripheral light due to a so-called cosine fourth law or the like. Of course, by using the CPU 142, control combining the second mode and the third mode is also possible.

  Next, the operation of the first embodiment of the imaging unit in the present invention will be described. FIG. 14 is a flowchart showing a flow of drive control of the light shielding device 117 in one imaging operation in the imaging apparatus 1 shown in FIG.

  In step S101, it is determined whether or not the first mode is selected for the control of the light shielding device 117. The mode selection for the control of the light shielding device 117 is selected by the CPU 142 based on the setting of the imaging operation selected by the input member 145 shown in FIG. For example, the first mode is selected when “simple dynamic range expansion shooting” is selected with the input member 145, and the second mode is “high speed shutter shooting” when “high accuracy dynamic range expansion shooting” is selected. When is selected, the third mode is selected.

  When the first mode is selected (step S101; YES), the processing after step S102 is executed. In step S102, the light shielding drive unit 113 is driven to set the light shielding amount of the light shielding member 112 to a predetermined value, and in step S103, the first time of the photoelectric conversion unit 111 is shorter than the time required for original photographing. Perform exposure.

  In step S104 (first calculation mode), based on the photoelectric conversion output 116 of the photoelectric conversion unit 111 by the first exposure in step S103, the light shielding amount calculation unit 121 calculates the light shielding amount at the time of shooting, and in step S105. Based on the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121, the light shielding driving unit 113 is driven by the light shielding control output 124 of the light shielding control unit 123 to control the light shielding amount of the light shielding member 112. Shooting is performed in S106.

  Thereafter, the photoelectric conversion output 116 of the photoelectric conversion unit 111 and the light shielding amount control value 122 calculated by the light shielding amount calculation unit 121 are transmitted to the output circuit 126. In step S107, the output circuit 126 amplifies the signal according to the light shielding amount, After predetermined signal processing such as noise removal is performed, the video signal 127 is output to the CPU 142 via the interface 143 in step S108. In step S109, the CPU 142 performs image processing suitable for recording or display on the video signal 127. In step S110, the video signal 127 is recorded as a known image file in the storage device 146 or displayed on the display 144.

  If the first mode is not selected in step S101 (step S101; NO), it is determined whether or not the second mode is selected in step S111. When the second mode is selected (step S111; YES), the processing after step S112 is executed. In step S112, the light shielding drive unit 113 is driven to set the light shielding amount of the light shielding member 112 to a predetermined value, and in step S113, the first time of the photoelectric conversion unit 111 is shorter than the time required for original photographing. Perform exposure.

  In step S114 (second calculation mode), based on the photoelectric conversion output 116 of the photoelectric conversion unit 111 by the first exposure in step S113, the CPU 142 calculates the light shielding amount at the time of shooting, and the second light shielding amount control value. 152 is input to the light shielding control unit 123. In step S115, the light shielding driving unit 113 is driven by the light shielding control output 124 of the light shielding control unit 123 based on the second light shielding amount control value 152 calculated by the CPU 142. The light shielding amount of the light shielding member 112 is controlled, and the process proceeds to step S106. Thereafter, the operations after step S106 described above are performed.

  If the second mode is not selected in step S111 (step S111; NO), the process proceeds to step S121. In step S121, various states of the imaging apparatus 1 are confirmed, and in step S122 (third calculation mode), an exposure calculation for adjusting the exposure time and aperture value is performed by the CPU 142 to obtain an appropriate aperture amount and shutter speed. The corresponding second light shielding amount control value 152 is input to the light shielding control unit 123, and the process proceeds to step S115. Thereafter, the operations after step S115 described above are performed.

  When the light shielding amount storage unit 128 is additionally provided in FIG. 13, the light shielding amount storage value 161 of the light shielding amount storage unit 128 that stores the current light shielding amount of the light shielding member 112, as indicated by a broken line in FIG. By inputting to the amount calculation unit 121, the light shielding amount calculation unit 121 can calculate the light shielding amount control value 122 based on the photoelectric conversion output 116 and the light shielding amount storage value 161. As a result, the first exposure is not necessary, and the operations in steps S102 and S103 can be omitted, so that a higher speed operation is possible.

  Similarly, by inputting the light shielding amount storage value 161 to the CPU 142 via the interface 143, the operations in step S112 and step S113 can be omitted. If the CPU 142 is used as the light shielding amount calculation unit, It is also possible to store the second light shielding amount control value 152 in the storage device 146 and use it to calculate the light shielding amount control value 122 for the next shooting.

  In the present embodiment, for example, when an FT (Frame Transfer) type CCD is used as the image sensor, after the photographing in step S105 is completed, until the photoelectric conversion output 116 of the photoelectric conversion unit 111 is transmitted to the output circuit 126. There is a case where it is desired to stop the light incident on the photoelectric conversion unit 111 during this time. This is because the FT-type CCD uses the photoelectric conversion unit 111 itself as a transfer path for the photoelectric conversion output 116, and therefore the photoelectric conversion output 116 itself changes when light enters during transfer. In such a case, a shutter device may be provided separately from the main imaging unit, or, as described above, the light shielding device 117 of the main imaging unit so as to be completely shielded simultaneously with the end of photographing in step S106. May be used as a shutter. In the former case, the control of the light shielding device 117 is simplified, and in the latter case, a separate shutter is unnecessary.

  When calculating the light shielding amount at the time of photographing in step S104, as described with reference to FIG. 6 described above, the pixel determined that the incident light amount is small (that is, dark) from the first exposure result has a small light shielding amount. If pixels that are judged to have a large amount of incident light (that is, bright) are made to have a large amount of light shielding, the pixels in the dark part will have sufficient sensitivity, and the photoelectric conversion unit 111 will not be saturated even in the pixels in the very bright part. Thus, the dynamic range expansion that is the object of the present invention is achieved.

  Note that the light shielding amount calculation unit control signal 125 input to the light shielding amount calculation unit 121 is mainly a signal for controlling the calculation timing and the like, but information about the pixel 110 that is the target of the light shielding amount calculation, for example, the image sensor 100. Information such as the position on the chip and the filter color may be included. If the light shielding amount is calculated based on these pieces of information, partial exposure control and color balance correction processing on the photographing screen can be simplified.

  In the present embodiment, in the second and subsequent shooting operations, the process of step S102 can be omitted, and the first exposure can be performed with the light shielding amount at the previous shooting. In this case, since it is not necessary to control the light shielding member 112 twice, the speed can be further increased.

  Next, a second embodiment of the imaging unit according to the present invention will be described with reference to FIGS. 15, 16, and 17 taking an imaging apparatus as an example.

  FIG. 15 is a circuit block diagram of the imaging apparatus 1 when attention is paid to one pixel 110 of the imaging element 100, and includes the imaging unit 10 and an imaging apparatus control unit 140 that functions as an imaging control unit.

  First, in FIG. 15, similarly to FIG. 10, the pixel 110 is provided with an incident light amount detection unit 131 that detects the incident light amount. The incident light amount detection unit 131 may be disposed at a position that is not shielded by the light shielding member 112, and may be provided on the pixel 110 or may be provided on the light shielding member 112. The incident light amount output 132 of the incident light amount detector 131 is input to the light shielding amount calculator 121.

  Further, as described with reference to FIG. 13, a light shielding amount storage unit 128 that stores a light shielding amount indicated by a broken line in FIG. 15 may be additionally provided for each pixel 110. This effect is also the same as described above with reference to FIG. Further, as indicated by a broken line in FIG. 15, the photoelectric conversion output 116 of the photoelectric conversion unit 111 is input to the light shielding amount calculation unit 121, and the photoelectric conversion output 116 is used instead of the incident light amount output 132 of the incident light amount detection unit 131. The light shielding amount may be calculated. The operation in this case is the same as that shown in FIGS.

  Next, the flow of drive control of the light shielding device 117 in the imaging apparatus 1 shown in FIG. 15 will be described using FIG. FIG. 16 is a flowchart showing a flow of drive control of the light shielding device 117 in one shooting operation of the imaging apparatus 1 according to the second embodiment.

  In step S201, it is determined whether or not the fourth mode is selected for the control of the light shielding device 117. When the fourth mode is selected (step S201; YES), in step S203, the incident light amount detection unit 131 is exposed in a time shorter than the time required for original photographing, and step S204 (fourth calculation mode) is performed. ), The light shielding amount calculation unit 121 calculates the light shielding amount at the time of photographing based on the incident light amount output 132 by the exposure of the incident light amount detection unit 131 in step S203, and the process proceeds to step S105. The subsequent processing is the same as that shown in FIG.

  Next, when the fourth mode is not selected in step S201 (step S201; NO), it is determined whether or not the fifth mode is selected in step S211. When the fifth mode is selected (step S211; YES), in step S213, the incident light amount detection unit 131 is exposed in a time shorter than the time required for original photographing, and step S214 (fifth calculation mode) is performed. In step S213, the CPU 142 calculates a light shielding amount at the time of photographing based on the incident light amount output 132 by the exposure of the incident light amount detector 131 in step S213, and the process proceeds to step S115. The subsequent processing is the same as that shown in FIG.

  If the fifth mode is not selected in step S211 (step S211; NO), the control is performed in the third mode as in FIG. 14, but this is the same as in FIG. Omitted.

  In the fourth mode, similarly to the first mode shown in FIG. 13, the light shielding amount calculation unit 121 on the imaging unit 10 calculates the light shielding amount based on the incident light amount output 132 (fourth calculation mode). ), The calculated light shielding amount control value 122 is input to the light shielding control unit 123, and the light shielding driving unit 113 is driven by the light shielding control output 124 of the light shielding control unit 123 to control the light shielding amount of the light shielding member 112.

  In the fifth mode, similarly to the second mode shown in FIG. 13, the CPU 142 calculates the light shielding amount based on the incident light amount output 132 input to the interface 143 (fifth calculation mode). The second light-shielding amount control value 152 is input to the light-shielding control unit 123 via the interface 143, and the light-shielding drive unit 113 is driven by the light-shielding control output 124 of the light-shielding control unit 123. Be controlled. That is, the CPU 142 functions as a light shielding amount calculation unit.

  Next, the drive control timing of the light shielding device 117 will be described with reference to FIG. FIG. 17 is a timing chart showing operation timings in the fourth and fifth modes of the flowchart shown in FIG. The same parts as those in FIGS. 13 to 16 are denoted by the same reference numerals, and the description thereof is omitted.

  When the fourth mode is selected in step S <b> 201, the incident light amount detection unit 131 detects the incident light amount in step S <b> 203 and transmits an incident light amount output 132 to the light shielding amount calculation unit 121. In step S <b> 204, the light shielding amount calculation unit 121 calculates a light shielding amount based on the incident light amount output 132, and transmits the light shielding amount control value 122 to the light shielding control unit 123 and the output circuit 126. In step S <b> 105, the light shielding amount control unit 123 drives the light shielding driving unit 113 with the light shielding control output 124 based on the light shielding amount control value 122 to move the light shielding member 112 to the light shielding position.

  On the other hand, the photoelectric conversion unit 111 performs imaging in step S <b> 106 and transmits the photoelectric conversion output 116 to the output circuit 126. In step S107, the output circuit 126 performs predetermined signal processing such as signal amplification and noise removal according to the light shielding amount on the photoelectric conversion output 116, and outputs the video signal 127 in step S108.

  When the fifth mode is selected in step S211, the incident light amount detector 131 detects the incident light amount in step S213 and transmits the incident light amount output 132 to the CPU 142. In step S <b> 214, the CPU 142 calculates a light shielding amount based on the incident light amount output 132 and transmits the second light shielding amount control value 152 to the light shielding control unit 123 and the output circuit 126. In step S115, the light shielding amount control unit 123 drives the light shielding driving unit 113 with the light shielding control output 124 based on the second light shielding amount control value 152, and moves the light shielding member 112 to the light shielding position. Since the subsequent steps are the same as described above, description thereof is omitted.

  In the present embodiment, during one shooting operation (from the start of step S106 to the completion of step S108), the calculation of the light shielding amount for the next shooting and the light shielding member control are executed in parallel. . Hereinafter, as described above, the light-shielding amount calculation operation using the incident light amount detection unit 131 and the imaging operation using the first photoelectric conversion unit 111 are repeated in parallel.

  Accordingly, in the flow of driving control of the light shielding member 112 in the first embodiment shown in FIG. 14, the imaging operation in the photoelectric conversion unit 111 is the first exposure in step S103 or step S113 and the imaging in step S106. However, in this second embodiment, since the imaging operation in the photoelectric conversion unit 111 is only for photographing in step 106, the video signal 127 is obtained. Time to get can be shortened.

  Similarly to the description of FIG. 14 described above, also in this example, a pixel determined to have a small amount of incident light (that is, dark) has a small amount of light shielding, and a pixel determined to have a large amount of incident light (that is, bright) If the number of pixels is increased, sufficient sensitivity can be obtained for dark pixels, and the photoelectric conversion unit 111 is less likely to be saturated even for very bright pixels, so that the dynamic range expansion that is the object of the present invention is achieved. .

  Furthermore, in the flow of drive control of the light shielding device 117 in the first embodiment shown in FIG. 14, the imaging operation in the photoelectric conversion unit 111 is performed by the first exposure in step S103 or step S113 and the imaging in step S106. Since it is necessary twice, it takes time until the video signal 127 is obtained. However, in the second embodiment, the video signal 127 is obtained because the imaging operation in the photoelectric conversion unit 111 is only the shooting in step 106. Can be shortened.

  Next, a third embodiment of the imaging unit according to the present invention will be described with reference to FIGS. 18 and 19 by taking an imaging apparatus as an example.

  FIG. 18 is a circuit block diagram of the image pickup apparatus 1 when attention is paid to one pixel 110 of the image pickup element 100. FIG. 18 omits the light shielding amount calculation unit 121 in the image pickup unit 10 from FIG.

  In FIG. 18, since the light shielding amount calculation unit 121 is omitted from FIG. 13, the light shielding amount control value 122 does not exist. Further, the photoelectric conversion output 116 of the photoelectric conversion unit 111 is input only to the output circuit 126. Of the three control modes of the light shielding device 117, the first mode does not exist. Others are the same as FIG.

  Next, the flow of drive control of the light shielding device 117 in the imaging apparatus 1 shown in FIG. 18 will be described using FIG. FIG. 19 is a flowchart showing a flow of drive control of the light shielding device 117 in one imaging operation in the imaging apparatus 1. As described above, the first mode does not exist among the three control modes of the light shielding device 117 in the first embodiment of the imaging unit of the present invention. That is, FIG. 19 is obtained by deleting steps S101 to S105 from FIG. Therefore, detailed description is omitted.

  According to the third embodiment, since the light shielding amount calculation unit 121 that requires a calculation function is not provided on the imaging unit 10 side, the circuit scale of the imaging unit 10 can be reduced, and the size can be reduced. It is advantageous for lowering the price. In addition, since the CPU 142 of the imaging device control unit 140 is used for light shielding amount calculation, it is possible to perform advanced light shielding amount calculation or make the light shielding amount calculation programmable.

  Finally, an example of the amount of light incident on the pixel 110 and the control of the light shielding device 117 will be described with reference to FIG. FIG. 20 is a graph showing the relationship between the amount of light incident on the pixel of the image sensor, the photoelectric conversion output of the photoelectric conversion unit 111 and the light shielding rate of the light shielding member 112 in the pixel. Here, the light shielding rate is the ratio of the area shielded by the light shielding member 112 to the total light receiving area of the photoelectric conversion unit 111, and is synonymous with the light shielding amount in the present invention.

  As shown in FIG. 6, the relationship between the incident light amount and the photoelectric conversion output 116 is a linear relationship, and it is possible to prevent the output from being saturated by switching the light shielding rate. By switching the light shielding rate, the same photoelectric conversion output 116 is obtained for different incident light amounts (for example, V (B0) indicated by a one-dot chain line in FIG. 6). For this purpose, in the circuit block diagrams shown in FIGS. 13, 15, and 18, the light shielding amount control value 122 or the second light shielding amount control value 152 is input to the output circuit 126, and the photoelectric conversion output is based on the information. The relationship between 116 and the amount of incident light can be uniquely converted.

Here, it is considered that the relationship between the incident light quantity and the photoelectric conversion output is uniquely determined. If the incident light quantity is P and the light shielding rate is k, the received light amount Y of the photoelectric conversion unit 111 is
Y = (1-k) P (Formula 1)
It becomes. Here, k is expressed as (Equation 1-1) below.

Then,

Thus, as an example of nonlinearity, the relationship between the received light amount Y and the incident light amount P is a square root relationship, and the relationship between the received light amount Y and the photoelectric conversion output is unambiguous, so the relationship between the incident light amount and the photoelectric conversion output is unambiguous. In addition, signal compression can be performed, and an expansion of the dynamic range can be achieved. FIG. 20 is a graph showing the relationship of (Formula 2) (provided that a = 1).

  By controlling the light shielding rate of the light shielding member 112 as shown by the curve A in FIG. 20, the photoelectric conversion output 116 shown by the curve B in FIG. 20 shows a relatively steep rise on the low luminance side, and the high luminance On the side, it can be compressed into a monotonically increasing graph close to a gentle straight line. From this, it can be seen that on the low luminance side, the output moves greatly with respect to a slight change in luminance and shows high sensitivity, and on the high luminance side, the expansion of the dynamic range can be achieved.

  With the method as described above, the relationship between the incident light quantity and the photoelectric conversion output 116 can be uniquely determined. Therefore, the light shielding amount control value 122 or the second light shielding amount shown in FIG. 13, FIG. 15, and FIG. It is not necessary to input the control value 152 to the output circuit 126. Of course, the function for non-linearization is not limited to the above. In the above-described calculation, it is desirable to perform analog / digital (A / D) conversion with as many bits as possible in order to suppress the generation of quantization noise, which is a suitable method for calculating the light shielding amount on the imaging device control unit 140 side. It is.

  As described above, according to the present invention, the light shielding member that shields the photoelectric conversion unit is provided on the pixel, and the light shielding amount is controlled to expand the dynamic range, and also include the shutter function and the aperture function. An image pickup device, an image pickup unit, and an image pickup apparatus can be provided.

  Note that the detailed configuration and detailed operation of each component constituting the imaging device, imaging unit, and imaging apparatus of the present invention can be changed as appropriate without departing from the spirit of the present invention.

It is a schematic diagram of an image sensor which is one embodiment of the present invention. It is a schematic diagram which shows the arrangement | sequence of the pixel for demonstrating the definition of the distance between columns. It is a schematic diagram which shows 1st Embodiment of the light-shielding device in this invention. It is a schematic diagram which shows 2nd Embodiment of the light-shielding device in this invention. It is a schematic diagram which shows 3rd Embodiment of the light-shielding device in this invention. It is a schematic diagram which shows the relationship between the light shielding in this invention, and a dynamic range, and is a graph of the photoelectric conversion characteristic which took the incident light quantity (B) on the horizontal axis, and took the imaging output (V) on the vertical axis | shaft. It is a schematic diagram which shows 4th Embodiment of the light-shielding device in this invention. 1 is a diagram illustrating a first embodiment of an image sensor according to the present invention, and is a circuit block diagram when attention is paid to one pixel of the image sensor. FIG. It is a flowchart which shows the flow of operation | movement of the circuit block shown in FIG. It is a figure which shows 2nd Embodiment of the image pick-up element in this invention, and is a circuit block diagram when paying attention to one pixel of an image pick-up element. 11 is a flowchart showing an operation flow of the circuit block shown in FIG. 10. It is a timing chart which shows the operation timing of the light-shielding device in this invention. 1 is a circuit block diagram of an imaging apparatus that is a first embodiment of an imaging unit to which an imaging device including a light-shielding device according to the present invention is applied. 14 is a flowchart showing an operation flow of the circuit block shown in FIG. 13. It is a circuit block diagram of the imaging device which is 2nd Embodiment of the imaging unit to which the imaging device provided with the light-shielding device in this invention was applied. 16 is a flowchart showing an operation flow of the circuit block shown in FIG. 15. 16 is a timing chart showing operation timing of the circuit block shown in FIG. 15. It is a circuit block diagram of the imaging device which is 3rd Embodiment of the imaging unit to which the imaging device provided with the light-shielding device in this invention was applied. FIG. 19 is a flowchart showing an operation flow of the circuit block shown in FIG. 18. FIG. It is a graph which shows the relationship between an incident light quantity, a photoelectric conversion output, and a light-shielding rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 10 Imaging unit 100 Image pick-up element 110 Pixel 111 Photoelectric conversion part 112 Light-shielding member 113 Light-shielding drive part 113a 1st comb-tooth-shaped electrode 113b 2nd comb-tooth-shaped electrode 114 Rotating shaft 115 Support point 116 Photoelectric conversion output 117 Light-shielding device 121 Shading amount calculation unit 122 Shading amount control value 123 Shading control unit 124 Shading control output 125 Shading amount calculation unit control signal 126 Output circuit 127 Video signal 128 Shading amount storage unit 131 Incident light amount detection unit 132 Incident light amount output 140 Imaging device control unit 141 Bus 142 CPU (Central Processing Unit)
143 Interface 144 Display 145 Input member 146 Storage device 152 Second light shielding amount control value 161 Light shielding amount storage value

Claims (14)

Pixels with photoelectric conversion parts are arranged in a two-dimensional shape,
A pixel column in which at least one side is arranged in the arrangement direction of a certain pixel, and a pixel column adjacent to the pixel column, in order to variably shield all or part of incident light to the photoelectric conversion unit; A light shielding member shorter than the distance of
An image pickup device comprising: a light shielding device including a light shielding driving unit for moving the position of the light shielding member on the photoelectric conversion unit. The imaging device according to claim 1, wherein the light shielding members are connected to each other at an end portion. The imaging device according to claim 1, further comprising an incident light amount detection unit that detects an incident light amount to the pixel. The imaging device according to claim 1, further comprising: a light shielding amount storage unit that stores a light shielding amount that the light shielding device shields from light. The imaging device according to claim 3, further comprising: a light shielding amount storage unit that stores a light shielding amount that the light shielding device shields from light. The imaging device according to claim 1, wherein the light shielding drive unit moves the light shielding member with an electromagnetic force. The imaging device according to any one of claims 1 to 6,
An imaging unit comprising: a light shielding control unit that variably controls a light shielding amount of light shielding by a light shielding device included in the imaging element. The image sensor according to any one of claims 1, 2, or 4,
Based on the photoelectric conversion output of the photoelectric conversion unit provided in the image sensor, a light shielding amount calculation unit having a first calculation mode for calculating the light shielding amount of the light shielding device provided in the image sensor;
An imaging unit, comprising: a light-blocking control unit that controls a light-blocking amount that the light-blocking device blocks light according to a calculation result of the light-blocking amount calculation unit having the first calculation mode. The image sensor according to claim 4,
Based on the photoelectric conversion output of the photoelectric conversion unit included in the imaging device and the light shielding amount stored in the light shielding amount storage unit included in the imaging device, the light shielding amount for calculating the light shielding amount that the light shielding member included in the imaging device shields. A calculation unit;
An imaging unit, comprising: a light shielding control unit that controls a light shielding amount of the light shielding device according to a calculation result of the light shielding amount calculation unit. The image sensor according to claim 3 or 5,
A light-blocking amount calculation unit having a fourth calculation mode for calculating a light-blocking amount of a light-blocking device included in the imaging device, based on the incident light amount detected by the incident light amount detection unit included in the imaging element;
An imaging unit comprising: a light shielding control unit that controls a light shielding amount of the light shielding device according to a calculation result of the light shielding amount calculation unit having the fourth calculation mode. An imaging unit according to claim 7;
An imaging apparatus comprising: an imaging control unit that controls imaging by an imaging element included in the imaging unit. The imaging unit according to claim 8 or 9,
An imaging control unit that controls imaging by an imaging element included in the imaging unit;
An output circuit that outputs a photoelectric conversion output of a photoelectric conversion unit included in the imaging device as a video signal;
The imaging control unit includes a light shielding amount calculation unit having a second calculation mode for calculating a light shielding amount of a light shielding device included in the imaging device based on a video signal output of the output circuit. apparatus. The imaging unit according to claim 10;
An imaging control unit that controls imaging by an imaging element included in the imaging unit;
The imaging control unit includes a light-blocking amount calculation unit having a fifth calculation mode for calculating a light-blocking amount of a light-blocking device included in the imaging element based on an incident light amount output of an incident light amount detection unit included in the imaging unit. An imaging apparatus characterized by that. The imaging unit according to any one of claims 8 to 10,
An imaging control unit that controls imaging by an imaging element included in the imaging unit;
The imaging apparatus, comprising: a light shielding amount calculation unit having a third calculation mode for calculating a light shielding amount of a light shielding device included in the imaging device based on a state of the imaging device.

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