JP4200270B2 - Light amount adjustment device, lens barrel, imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light amount adjusting device for controlling the amount of received light, a lens barrel having the light amount adjusting device, and an imaging device having the imaging device, which are suitable for optical devices such as video cameras and still cameras.
[0002]
[Prior art]
In a video camera or still camera that uses a lens barrel that combines multiple lenses to form a light beam on an image sensor or film surface and record a moving image or still image, capture the image in the middle of the lens barrel optical system. It is common to incorporate a light amount adjusting device for controlling the amount of light received by the element. Especially for video cameras and digital still cameras that shoot movies or display them on a liquid crystal display, etc., the amount of light that continuously controls the amount of light received so that the amount of received light remains constant following changes in the illuminance of the subject. An adjustment device is required.
[0003]
In recent years, when the pixel pitch of the image sensor is reduced, a light amount adjustment device that reduces the resolution when the aperture is reduced and that continuously controls the amount of received light is required. Equipment has been developed. As an example, Japanese Patent Application Laid-Open No. 11-64921 discloses a lens diaphragm adjusting device which is one of the light amount adjusting devices. An example of such a light quantity adjusting device is shown in FIG.
[0004]
In FIG. 18, on the optical axis 100 of the imaging optical system lenses 121, 122, 123, and 124, the diaphragm blades 106 and 107 controlled by the diaphragm driving unit 105 and the ND filter driving unit 103 are put in and out of the optical path. An ND filter (a neutral density filter) 104 is disposed. The ND filter 104 and the diaphragm blades 106 and 107 are controlled independently of each other.
[0005]
The subject image that has passed through these imaging optical systems forms an image on the image sensor 109. A signal from the image sensor 109 is converted into a standard television signal or the like by the video signal processing circuit 108 and is output to an external recording unit, a television monitor or the like (not shown).
[0006]
A luminance signal of the subject is input from the video signal processing circuit 108 to the light amount control unit 110. The light amount control unit 110 outputs control signals to the ND filter driving unit 103 and the diaphragm driving unit 105 so that the amount of light incident on the image sensor 109 is constant.
[0007]
In FIG. 19, which is a perspective view of the main components of the light amount adjusting device, the rotor 3 is press-fitted and fixed to the first meter 2 that constitutes the diaphragm drive unit attached to the base 1. Aperture blades 106 and 107 are attached. The diaphragm blades 106 and 107 are provided with inclined edges 131 and 132, which are used to block part or all of the optical path.
[0008]
When electric power is supplied to the first meter 2 from the outside, the rotor 3 rotates, and the diaphragm blades 106 move downward and the diaphragm blades 107 move upward along the guide pins provided on the base 1. Further, when the rotor 3 rotates in the opposite direction, the diaphragm blades 106 move upward and the diaphragm blades 107 move downward along the guide pins provided on the base 1. As a result, the amount of light incident on the image sensor 109 can be adjusted by adjusting the power supplied to the first meter 2.
[0009]
On the other hand, the ND drive blade 6 is provided with a sufficiently large opening 111 with respect to the circular opening provided in the base 1, and the ND filter 104 is bonded and fixed so as to cover this. An arm 5 is press-fitted and fixed to the second meter 4 fixed to the lens barrel, and an ND driving blade 6 is attached to the tip of the arm 5, so that the ND driving blade 6 and the ND filter 104 are changed according to the rotation of the arm 5. Move up and down together.
[0010]
When electric power is supplied to the second meter 4 from the outside, the arm 5 rotates, and the ND drive blade 6 moves upward along a guide pin (not shown). Further, when the arm 5 rotates in the opposite direction, the ND drive blade 6 moves downward along a guide pin (not shown). As a result, by adjusting the power supplied to the second meter 4, the ND filter 104 can be gradually inserted into the optical path from the retracted position or pulled out from the optical path to the retracted position. Since the ND filter 104 has a transmittance of, for example, about 10% to 30%, the amount of light incident on the image sensor 109 can be continuously adjusted.
[0011]
The operation of the light amount adjusting apparatus having the above configuration will be described with reference to FIG. In FIG. 20, the optical axis 100 is in a direction perpendicular to the paper surface. When the illuminance of the subject is low, as shown in FIG. 20A, the ND filter 104 is retracted from the optical path, and the aperture blades 106 and 107 are fully opened so as not to block the optical path.
[0012]
When the illuminance of the subject starts to increase, the diaphragm blades 106 and 107 are first driven to reduce the cross-sectional area of the optical path. After the diaphragm blades 106 and 107 reach the position shown in FIG. 20 (b), the ND filter 104 is inserted into the optical path as shown in FIGS. 20 (c) and 20 (d), and eventually the optical path as shown in FIG. 20 (e). Cover completely. During this time, the diaphragm blades 106 and 107 are stopped. In the state shown in FIG. 20 (d), the small aperture region 115 is formed and the resolution deteriorates due to the diffraction phenomenon. However, since the ratio of the small aperture region 115 occupying the entire cross-sectional area of the optical path is low, the overall resolution is reduced. Degradation can be suppressed.
[0013]
When the illuminance of the subject further increases, the diaphragm blades 106 and 107 are driven, and the cross-sectional area of the optical path is further reduced as shown in FIG. As described above, it is possible to keep the amount of light incident on the image sensor 109 constant with respect to increase / decrease in the subject illuminance while reducing resolution degradation due to diffraction.
[0014]
[Problems to be solved by the invention]
However, in such a light amount adjusting device, the aperture opening shape is determined by the inclined edges 131 and 132 of the aperture blades 106 and 107, and thus there is a problem that the blur is bad.
[0015]
Here, the blur is a blurred state of the background or foreground with respect to the main subject, and strongly depends on the shape of the aperture opening at the time of photographing as introduced in Japanese Patent Laid-Open No. 2002-40519. As a general image evaluation standard, it is considered that a state where the main subject is uniformly blurred in all directions from the background or the foreground is good. Therefore, it is desirable that the aperture opening shape is close to a circle.
[0016]
However, in the light quantity adjusting device shown in FIG. 20, the aperture opening shape is always square except in the range (b) to (f), that is, the case where the subject brightness is the lowest (a). In the case of a square opening shape, the way of blur is extremely different between the up / down / left / right direction and the oblique direction, and the blur is generally poor. In addition, when a subject having a high-luminance part such as a sunbeams in the background is photographed in such a state where the aperture opening shape is a quadrangle, the sunbeams are blurred and close to a quadrangle similar to the aperture shape of the aperture. Image. Particularly in high-resolution still image shooting, such blurring is regarded as an unnatural image.
[0017]
In recent years, with video cameras and digital still cameras, the larger the number of still image pixels that can be recorded, the more high-class models are considered, and in order to form as many pixels as possible on an image sensor of the same area, The pixel pitch is being reduced. The light amount adjustment device of the prior art described in FIGS. 18 to 20 was developed as a light amount adjustment device with little deterioration in resolution in a small aperture state even when the pixel pitch of the image sensor is reduced under such a background. It is.
[0018]
However, high-quality video cameras and digital still cameras have high-grade specifications, so the blur must be natural. In addition, a continuous light intensity adjustment function is essential for moving image shooting.
[0019]
SUMMARY OF THE INVENTION An object of the present invention is to provide a light amount adjustment device capable of capturing a more preferable blurred image in order to answer such market needs. In addition, an object of the present invention is to provide a light amount adjusting device that has little degradation in resolution due to diffraction when performing light amount adjustment, and also has a continuous light amount adjusting function necessary for moving image shooting. Another object of the present invention is to provide a lens barrel and an imaging device having the above-described light amount adjusting device.
[0020]
[Means for Solving the Problems]
In order to solve this problem, a first light amount adjusting device of the present invention is a light amount adjusting device provided in an optical path of an imaging optical system that forms a subject image.
The shielding area of the optical path can be increased or decreased plural A first aperture blade;
By being driven by a driving means different from the driving means for driving the first aperture blade, and being put in and out of the optical path A neutral density filter capable of changing the transmittance of light passing through the optical path;
Operates integrally with the neutral density filter to increase or decrease the shielding area of the optical path And shielding the intersection of the edges on the opening side of the plurality of first diaphragm blades. A second diaphragm blade,
Increasing / decreasing the shielding area of the optical path by the plurality of first diaphragm blades and increasing / decreasing the shielding area of the optical path by the second diaphragm blades And shielding of intersections of edges on the opening side of the plurality of first diaphragm blades And the neutral density filter Access to and from the light path The amount of light passing through the optical path is adjusted by combining with the change in transmittance due to.
[0021]
According to a second light amount adjusting device of the present invention, in the first light amount adjusting device, further, a first driving unit for taking the first diaphragm blade into and out of the optical path;
Second driving means for taking the second diaphragm blade into and out of the optical path;
When the subject illuminance is in the first illuminance range, the first diaphragm blade is stopped, and the second driving means drives the second diaphragm blade according to the change in the subject illuminance, and While increasing or decreasing the shielding area of the optical path by the second aperture blade,
The amount of light passing through the optical path is adjusted by a change in transmittance by the neutral density filter that operates integrally with the second diaphragm blade.
[0022]
According to a third light amount adjusting device of the present invention, in the second light amount adjusting device, when the subject illuminance is in a second illuminance range higher than the first illuminance range, the second light amount adjusting device is configured to change the second illuminance according to a change in the subject illuminance. The amount of light passing through the optical path is adjusted by changing the transmittance of the neutral density filter that operates integrally with the second aperture blade while keeping the shielding area of the optical path by the aperture blade constant.
[0023]
According to a fourth light quantity adjusting device of the present invention, in the first light quantity adjusting device, a first driving means for taking the first diaphragm blade into and out of the optical path, and the second diaphragm blade in the optical path. Second driving means for taking in and out,
When the subject illuminance is in the first illuminance range, the first diaphragm blade is stopped,
The second diaphragm blades are stopped at a plurality of positions where transmittance by the neutral density filter is uniform in a cross section perpendicular to the optical path, and the amount of light passing through the optical path is adjusted.
[0024]
According to a fifth light amount adjusting device of the present invention, in the fourth light amount adjusting device, when the subject illuminance is in a second illuminance range higher than the first illuminance range, the first driving means The second driving means drives the second diaphragm blade, and the transmittance of the neutral density filter is uniform in a cross section perpendicular to the optical path, and The first diaphragm blade and the second diaphragm blade are stopped at a position where the shielding area of the optical path by the diaphragm blade and the second diaphragm blade is increased together with the light shielding area in the first illuminance range. And
[0025]
According to a sixth light amount adjusting apparatus of the present invention, in any one of the first to fifth light amount adjusting apparatuses, the first light amount adjusting apparatus includes a first detection unit that detects a position of the first diaphragm blade, The first aperture blade is positioned according to the output of the detection means.
[0026]
According to a seventh light amount adjusting apparatus of the present invention, in the sixth light amount adjusting apparatus, the seventh light amount adjusting apparatus includes a second detecting unit that detects a position of the second diaphragm blade, and outputs the first detecting unit and the first detecting unit. The second diaphragm blade is positioned at a position where the output of the second detection means has a predetermined relationship.
[0027]
The lens barrel of the present invention includes any one of the first to seventh light amount adjusting devices and an imaging optical system that forms a subject image.
[0028]
According to a first imaging device of the present invention, the light amount adjusting device according to any one of the first to seventh embodiments, an imaging optical system that forms a subject image, and the formed subject image are received. An image sensor.
[0029]
According to a second imaging device of the present invention, in the first imaging device, a mechanical shutter operation is performed by fully closing an optical path with the first diaphragm blades in response to a user's still image shooting instruction. .
[0030]
According to a third imaging device of the present invention, in the first imaging device, a mechanical shutter operation is performed by fully closing an optical path with the first diaphragm blade and the second diaphragm blade according to a user's still image photographing instruction. It is characterized by performing. According to a fourth imaging device of the present invention, in the first imaging device, in accordance with a user's still image shooting instruction, an exposure time accumulated by the imaging device is determined, and a light accumulation time of the imaging device is determined. It is characterized by being variable.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected and demonstrated to the structural member shown previously in the prior art example.
[0032]
(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration of an imaging apparatus including a light amount adjustment apparatus according to the first embodiment. FIG. 2 is a perspective view of the main components of the light amount adjusting device according to the first embodiment.
[0033]
FIG. 3 is a partial front view of the light amount adjusting apparatus according to the first embodiment. FIG. 4 is a partial front view showing an operation comparison between the light amount adjusting device according to the first embodiment and the conventional light amount adjusting device.
[0034]
In FIG. 1, the imaging optical system lens includes a front lens group 121, a zoom lens group 122, a correction lens group 123, and a focus lens group 124. When the zoom lens group 122 moves back and forth along the optical axis 100, a zooming operation is performed, and when the focus lens group 124 moves back and forth, a focus adjustment operation is performed.
[0035]
On the optical axis 100, diaphragm blades 151 and 152 that are first diaphragm blades controlled by a first driving unit 141 that is first driving means are arranged. Further, in front of the diaphragm blades 151 and 152, the diaphragm blade 153 which is the second diaphragm blade controlled by the second driving unit 143 serving as the second driving means is disposed.
[0036]
An ND filter 154, which is a neutral density filter, is bonded and fixed to the diaphragm blade 153, and operates integrally with the diaphragm blade 153 so that it can be taken in and out of the optical path by the second drive unit 143.
[0037]
The diaphragm blades 153 and the ND filter 154 are controlled independently of the diaphragm blades 151 and 152.
[0038]
The positions of the diaphragm blades 151 and 152 are detected by the first detection unit 142 and input to the light amount control unit 110 as a first diaphragm blade position signal. The positions of the diaphragm blades 153 and the ND filter 154 are detected by the second detection unit 144 and input to the light amount control unit 110 as second diaphragm blade position signals.
[0039]
The subject image that has passed through the imaging optical system is formed on the image sensor 109. A signal from the image sensor 109 is converted into a standard television signal or the like by the video signal processing circuit 108 and is output to an external recording unit, a television monitor or the like (not shown).
[0040]
A luminance signal of the subject is input from the video signal processing circuit 108 to the light amount control unit 110. The light amount control unit 110 refers to the outputs of the first detection unit 142 and the second detection unit 144 so that the amount of light incident on the image sensor 109 is constant, and the first drive unit 141 and the second drive unit 143. Output a control signal.
[0041]
In FIG. 2, the rotor 3 is press-fitted and fixed to the first meter 2 that constitutes the diaphragm drive unit attached to the base 1, and the diaphragm blades 151 and 152 are attached to the both ends of the rotor 3. The diaphragm blades 151 and 152 are provided with V-shaped inclined edges 161 and 162 having apex angles of about 120 °, respectively, and are used to block part or all of the optical path.
[0042]
When electric power is supplied to the first meter 2 from the outside, the rotor 3 rotates and the diaphragm blades 151 move downward and the diaphragm blades 152 move upward along the guide pins provided on the base 1.
[0043]
Further, when the rotor 3 rotates in the opposite direction, the diaphragm blades 151 move upward and the diaphragm blades 152 move downward along the guide pins provided on the base 1. When the diaphragm blades 151 and 152 move in this way, the area where the inclined edges 161 and 162 block the optical path changes.
[0044]
As a result, by adjusting the power supplied to the first meter 2, the cross-sectional area of the optical path that passes through the light amount adjusting device changes around the optical axis 100, so that the amount of light incident on the image sensor 109 can be adjusted.
[0045]
A hall element (not shown) is attached inside the first meter 2. This Hall element detects a change in magnetic force due to rotation of the magnet of the first meter 2 to detect the positions of the diaphragm blades 151 and 152, and constitutes a first detection unit 142 which is a first detection means.
[0046]
On the other hand, the diaphragm blade 153 is provided with a V-shaped inclined edge 163 having an apex angle of, for example, about 30 °, and the ND filter 154 is bonded and fixed to a position covering most of the portion excluding the upper portion. The second meter 4 fixed to the lens barrel is press-fitted and fixed with the arm 5, and the diaphragm blade 153 is attached to the tip of the arm 5 so that the diaphragm blade 153 and the ND filter 154 are integrated as the arm 5 rotates. Move up and down.
[0047]
When electric power is supplied to the second meter 4 from the outside, the arm 5 rotates and the diaphragm blades 153 move upward along guide pins (not shown). Further, when the arm 5 rotates in the opposite direction, the aperture blade 153 moves downward along a guide pin (not shown).
[0048]
As a result, by adjusting the power supplied to the second meter 4, the diaphragm blade 153 and the ND filter 154 can be gradually inserted into the optical path from the retracted position, or pulled out from the optical path to the retracted position. it can. When the diaphragm blade 153 moves up and down, the area where the inclined edge 163 blocks the optical path changes.
[0049]
Further, since the ND filter 154 has a transmittance of about 10% to 30%, for example, when the diaphragm blade 153 moves up and down, the average transmittance of the light beam passing through the optical path changes continuously. Therefore, the amount of light incident on the image sensor 109 can be continuously adjusted in accordance with the increase or decrease of the area shielded by the inclined edge 163 of the diaphragm blade 153.
[0050]
A hall element (not shown) is attached inside the second meter 4. This Hall element detects a change in magnetic force due to the rotation of the magnet of the second meter 4 to detect the position of the diaphragm blade 153, and constitutes a second detection unit 144 serving as second detection means.
[0051]
The operation of the light amount adjusting apparatus configured as described above will be described with reference to FIG. In FIG. 3, the optical axis 100 is in a direction perpendicular to the paper surface.
[0052]
Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0053]
First, when the illuminance of the subject is low, as shown in FIG. 3A, the diaphragm blade 153 and the ND filter 154 are retracted from the optical path, and the diaphragm blades 151 and 152 are fully opened so as not to block the optical path. When the illuminance of the subject starts to increase, the first driving unit 141 drives the diaphragm blades 151 and 152, moves the diaphragm blade 151 downward, and moves the diaphragm blade 152 upward. As a result, the area where the inclined edges 161 and 162 block the light path increases. At the same time, the second driving unit 143 drives the diaphragm blade 153 to move it upward.
[0054]
Then, the inclined edge 163 having an apex angle narrower than that of the inclined edges 161 and 162 blocks a part of the optical path sandwiched between the inclined edges 161 and 162. As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIGS. At the same time, since the ND filter 154 also moves upward, the average transmittance of the optical path passing through the light amount adjusting device is also reduced, and the amount of light incident on the image sensor 109 can be kept constant.
[0055]
When the illuminance of the subject further increases, the diaphragm blade 151 moves downward, the diaphragm blade 152 moves upward, and the diaphragm blade 153 moves upward, so that the cross-sectional area of the optical path passing through the light amount adjusting device is increased. As shown in FIGS. 3D and 3E, the amount of light incident on the image sensor 109 can be kept constant.
[0056]
As shown in FIG. 3B, the small aperture region 115 is formed between the ND filter 154 and the inclined edge 161 of the aperture blade 151 immediately before the ND filter 154 covers the entire surface of the optical path. Since the area ratio of the small aperture region 115 occupying the entire cross-sectional area of the optical path is small, deterioration in resolution can be suppressed.
[0057]
3C, after the ND filter covers the entire surface of the optical path, the inclined edge 161 of the diaphragm blade 151, the inclined edge 162 of the diaphragm blade 152, and the inclined edge 163 of the diaphragm blade 153 are shielded from light. As the area to be increased increases, the amount of light incident on the image sensor 109 can be kept constant, so that a small aperture region is not formed and the resolution does not deteriorate due to the diffraction phenomenon.
[0058]
In addition, since the apex angle of the inclined edge 163 is about 30 ° and the apex angle of the inclined edges 161 and 162 is about 120 °, the shape of the opening is shown in FIG. During e), a hexagonal opening shape can be maintained. Compared to the rectangular aperture shape in the prior art, the hexagonal aperture shape can be kept more nearly circular, so that a more natural blur image can be taken.
[0059]
Here, the operation stroke of the aperture blade 151 will be described with reference to FIG. In FIG. 4, the diaphragm blade 106 in the prior art is also shown for comparison. In the diaphragm blade 106 in the prior art shown in FIG. 4 (b), it is necessary to form the diaphragm only by the two diaphragm blades 106 and 107. Therefore, the apex angle S1 of the V-shaped inclined edge is about 90 °. There is a need to.
[0060]
On the other hand, in the diaphragm blade 151 in the present embodiment, the apex angle S2 of the V-shaped inclined edge 161 can be increased to about 120 °. For this reason, the operation stroke H2 of the diaphragm blade 151 in this embodiment is suppressed to a short stroke of about 82% with respect to the operation stroke H1 from the fully open state to the fully closed state of the diaphragm blade 106 in the prior art. be able to. For this reason, the height of the whole light quantity adjustment apparatus can also be made low, a more compact light quantity adjustment apparatus can be provided, and therefore a smaller lens barrel can be provided.
[0061]
Further, since the operation stroke is short, the shutter time from the fully open state to the fully closed state can be shortened when the diaphragm blades 151 and 152 are mechanically operated.
[0062]
Alternatively, if the same shutter time is sufficient, the second meter 4 for driving the diaphragm blades 151 and 152 can be changed to a small output but a small size such as an outer diameter. Therefore, there is also a feature that a smaller lens barrel can be provided.
[0063]
Next, operations of the first detection unit 142, the second detection unit 144, and the light amount control unit 110 will be described in more detail. The light amount controller 110 changes the illuminance of the subject while referring to the output of the first detector 142 that detects the positions of the aperture blades 151 and 152 and the output of the second detector 144 that detects the position of the aperture blades 153. In response, a control signal is output to the first drive unit 141 and the second drive unit 143.
[0064]
At this time, the control signal is adjusted so that the output of the second detector 144 has a predetermined relationship with the output of the first detector 142.
[0065]
For example, in the case of shifting from the state of FIG. 3C to the state of FIG. 3D where the subject illuminance is high, if the movement amount of the diaphragm blades 151 and 152 is ΔH, the movement amount of the diaphragm blade 153 is ΔH. Let K1 × ΔH, which is a constant multiple. The value of the constant K1 can be determined in advance according to the ratio of the apex angle of the inclined edges 161 and 162 and the apex angle of the inclined edge 163. Thus, if the ratio of the movement amount of the diaphragm blade 153 to the movement amount of the diaphragm blades 151 and 152 is kept substantially constant, the aperture shape of the optical path can be kept substantially similar.
[0066]
Therefore, since the opening shape can be maintained in a hexagonal shape that is similar to a circular shape, a more natural blurred image can be taken.
[0067]
In the first embodiment, the apex angle of the inclined edge 161 and the apex angle of the inclined edge 162 are the same. However, for example, the inclined edge 161 is 110 ° and the inclined edge 162 is 130 °. The apex angle may be set to an angle at which the opening shape is closer to a circle and the degree of blur of the captured image is most natural.
[0068]
In the first embodiment, only the case where the illuminance of the subject increases has been described. However, even when the illuminance of the subject decreases, the light amount adjustment device operates in the same manner according to the illuminance of the subject, and The amount of incident light can be kept constant.
[0069]
As described above, the light amount adjusting apparatus according to the first embodiment increases / decreases the shielding area of the optical path by the inclined edges 161, 162 of the diaphragm blades 151, 152 and increases / decreases the shielding area of the optical path by the inclined edge 163 of the diaphragm blade 153. And the illuminance of the subject from the low illuminance of the subject (corresponding to FIGS. 3 (a) to 3 (b)) due to the continuous change in the average transmittance of the light beam passing through the optical path due to the insertion and removal of the ND filter 154. Until it is high (corresponding to FIGS. 3D to 3E), the amount of light incident on the image sensor 109 can be kept constant.
[0070]
Moreover, the opening shape of the optical path can be maintained in a substantially similar hexagonal shape. Therefore, the lens barrel using this light amount adjusting device can provide a more natural blur, and the video camera and digital still camera using the lens barrel can be used for shooting high-resolution still images. Since it can shoot more natural blurred images, it can be offered to the market as a higher-quality video camera or digital still camera.
[0071]
(Embodiment 2)
FIG. 5 is a perspective view of main components of the imaging apparatus including the light amount adjustment apparatus according to the second embodiment. FIG. 6 is a partial front view of the imaging apparatus including the light amount adjustment apparatus according to the second embodiment. FIG. 7 is a partial front view showing an operation comparison of the imaging device including the light amount adjusting device in the second embodiment. In the second embodiment, the description of the same part as the description of the first embodiment is omitted.
[0072]
In the second embodiment, the diaphragm blade 151 is provided with a V-shaped inclined edge 161 having an apex angle of about 108 °, and the diaphragm blade 152 has a horizontal edge 164 that is substantially perpendicular to the moving direction of the diaphragm blade 152. Was provided. The diaphragm blade 153 is provided with a V-shaped inclined edge 163 having an apex angle of about 36 °.
[0073]
The operation of the light amount adjusting apparatus configured as described above will be described with reference to FIG. In FIG. 6, the optical axis 100 is in a direction perpendicular to the paper surface. Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0074]
First, when the illuminance of the subject is low, as shown in FIG. 6A, the diaphragm blades 153 and the ND filter 154 are retracted from the optical path, and the diaphragm blades 151 and 152 are fully opened so as not to block the optical path. When the illuminance of the subject starts to increase, the first driving unit 141 drives the diaphragm blades 151 and 152, moves the diaphragm blade 151 downward, and moves the diaphragm blade 152 upward. As a result, the area where the inclined edge 161 and the horizontal edge 164 shield the light path increases.
[0075]
At the same time, the second driving unit 143 drives the diaphragm blade 153 to move it upward. Then, the inclined edge 163 shields a part of the optical path sandwiched between the inclined edge 161 and the horizontal edge 164.
[0076]
As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIGS. 6 (b) and 6 (c). At the same time, since the ND filter 154 also moves upward, the average transmittance of the optical path passing through the light amount adjusting device is also reduced, and the amount of light incident on the image sensor 109 can be kept constant.
[0077]
When the illuminance of the subject further increases, the diaphragm blade 151 moves downward, the diaphragm blade 152 moves upward, and the diaphragm blade 153 moves upward, so that the cross-sectional area of the optical path passing through the light amount adjusting device is increased. Is reduced as shown in FIGS. 6D and 6E, and the amount of light incident on the image sensor 109 can be kept constant.
[0078]
As shown in FIG. 6B, in the state immediately before the ND filter 154 covers the entire surface of the optical path, the small aperture region 115 is formed between the ND filter 154 and the inclined edge 161 of the aperture blade 151. Since the area ratio of the small aperture region 115 occupying the entire cross-sectional area of the optical path is small, deterioration in resolution can be suppressed.
[0079]
6C, after the ND filter covers the entire surface of the optical path, the inclined edge 161 of the diaphragm blade 151, the horizontal edge 164 of the diaphragm blade 152, and the inclined edge 163 of the diaphragm blade 153 are shielded from light. As the area to be increased increases, the amount of light incident on the image sensor 109 can be kept constant, so that a small aperture region is not formed and the resolution does not deteriorate due to the diffraction phenomenon.
[0080]
Moreover, since light is shielded by the inclined edge 163 with the apex angle of 36 ° in addition to the inclined edge 161 and the horizontal edge 164 with the apex angle of about 108 °, between FIGS. 6 (b) to (e) It can be maintained in an almost regular pentagonal opening shape. Compared to the square aperture shape in the prior art, it can be kept in a regular pentagonal aperture shape that is closer to a circle and the length of one side is equal, so a more natural blur image can be taken. is there.
[0081]
Here, the operation strokes of the diaphragm blade 151 and the diaphragm blade 152 will be described with reference to FIG.
[0082]
FIG. 7A shows a fully open state, and FIG. 7B shows a fully closed state. In order to keep the aperture shape substantially regular pentagonal, it is necessary to keep the operation stroke H4 of the diaphragm blade 152 at a constant ratio with respect to the operation stroke H3 of the diaphragm blade 151. That is, H4 = K2 × H3 must be set. As a specific numerical value of K2, in this embodiment, when K2 = 0.81, the opening shape can be maintained in a regular pentagon. For this purpose, the distance L1 from the rotation center of the rotor 3 press-fitted and fixed to the first meter 2 to the pin for driving the diaphragm blade 151 and the distance L2 to the pin for driving the diaphragm blade 152 are expressed as L2 = K2 × What is necessary is just to set to the position used as L1.
[0083]
In comparison with the operation stroke H1 of the diaphragm blade 106 in the prior art shown in FIG. 4B, it is suppressed to about 90% even for H3 where the stroke becomes long, and to about 71% for H4 where the stroke becomes short. it can. For this reason, the height of the whole light quantity adjustment apparatus can also be made low, a more compact light quantity adjustment apparatus can be provided, and therefore a smaller lens barrel can be provided.
[0084]
Further, since the operation stroke is short, the shutter time from the fully open state to the fully closed state can be shortened when the diaphragm blades 151 and 152 are mechanically operated.
[0085]
Alternatively, if the same shutter time is sufficient, the second meter 4 for driving the diaphragm blades 151 and 152 can be changed to a small output but a small size such as an outer diameter. Therefore, there is also a feature that a smaller lens barrel can be provided.
[0086]
In the second embodiment, only the case where the illuminance of the subject increases has been described. However, even when the illuminance of the subject decreases, the light amount adjustment device operates in the same manner according to the illuminance of the subject, and The amount of incident light can be kept constant.
[0087]
As described above, the light amount adjusting apparatus according to the second embodiment is configured to increase or decrease the shielding area of the optical path by the inclined edge 161 of the diaphragm blade 151 and the horizontal edge 164 of the diaphragm blade 152, and the optical path by the inclined edge 163 of the diaphragm blade 153. When the subject has low illuminance (corresponding to FIGS. 6 (a) to (b)) due to the increase / decrease of the shielding area and the continuous change of the average transmittance of the light beam passing through the optical path due to the insertion / extraction of the ND filter 154 ) To when the subject illuminance is high (corresponding to FIGS. 6D to 6E), the amount of light incident on the image sensor 109 can be kept constant.
[0088]
In addition, the opening shape of the optical path can be maintained as a regular pentagon having substantially the same side length. Therefore, the lens barrel using this light amount adjusting device can provide a more natural blur, and the video camera and digital still camera using the lens barrel can be used for shooting high-resolution still images. Since it can shoot more natural blurred images, it can be offered to the market as a higher-quality video camera or digital still camera.
[0089]
(Embodiment 3)
FIG. 8 is a perspective view of main components of the imaging apparatus including the light amount adjustment apparatus according to the third embodiment. FIG. 9 is a partial front view of the imaging apparatus including the light amount adjustment apparatus according to the third embodiment. In the third embodiment, the description of the same part as the description of the first embodiment is omitted.
[0090]
In Embodiment 3, the diaphragm blade 153 is provided with a vertical edge 165 that is substantially parallel to the moving direction of the diaphragm blade 153 in addition to the inclined edge 163 having an apex angle of about 30 °. Then, the ND filter 154 is bonded and fixed at a position covering the portion surrounded by the vertical edge 165.
[0091]
The operation of the light amount adjusting apparatus configured as described above will be described with reference to FIG. In FIG. 9, the optical axis 100 is in a direction perpendicular to the paper surface. Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0092]
First, the case where the illuminance of the subject is low and the illuminance is low will be described.
[0093]
In the case of the lowest illuminance, as shown in FIG. 9A, the aperture blade 153 and the ND filter 1
54 is retracted from the optical path, and the aperture blades 151 and 152 are fully opened so as not to block the optical path. When the illuminance of the subject starts to increase, the first driving unit 141 drives the diaphragm blades 151 and 152, moves the diaphragm blade 151 downward, and moves the diaphragm blade 152 upward. As a result, the area where the inclined edges 161 and 162 block the light path increases. At the same time, the second driving unit 143 drives the diaphragm blade 153 to move it upward.
[0094]
Then, the inclined edge 163 having a narrower apex angle than the inclined edges 161 and 162 shields a part of the optical path sandwiched between the inclined edges 161 and 162. As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIGS. 9B and 9C, and the light amount incident on the image sensor 109 can be kept constant. The shape of the opening in this section is a shape surrounded by the slanted edges 161 and 162 and the slanted edge 163, so that the shape is almost a hexagon. At this time, the ND filter 154 also moves upward, but since the vertical edge 165 has not entered the optical path, the ND filter 154 bonded and fixed so as to cover it slightly enters the optical path. Just do it.
[0095]
Here, the peripheral light amount ratio will be described. The peripheral light amount ratio indicates a light amount ratio between the central portion of the screen and the four corners. In general, when there is no ND filter, the peripheral light amount ratio deteriorates as the area of the aperture opening increases.
[0096]
That is, the peripheral light amount ratio tends to deteriorate when the illuminance of the subject is low and corresponds to low illuminance (corresponding to FIGS. 9A to 9B). The ratio depends on the optical design of the imaging optical system lens such as the front lens group 121, zoom lens group 122, correction lens group 123, and focus lens group 124. In order to provide a smaller video camera or still camera, and in turn to reduce the size of the lens barrel, even when the aperture is fully open, the minimum necessary peripheral light ratio cannot be secured even in the state shown in FIG. There is.
[0097]
In such an imaging optical system, if a part of the ND filter 154 is inserted in the optical path in a state close to the full aperture, the peripheral light amount ratio may be further deteriorated, and a part of the screen may become extremely dark.
[0098]
However, in the third embodiment, the vertical edge 165 does not enter the optical path in the case of low illuminance where the peripheral light amount ratio is a problem (corresponding to FIGS. 9A to 9B). The front end of the ND filter 154 that is bonded and fixed so as to cover the light slightly enters the optical path. For this reason, the decrease in the peripheral light amount ratio due to the ND filter can be suppressed to a negligible level.
[0099]
When the subject illuminance further increases, the diaphragm blades 151 and 152 stop, and only the diaphragm blades 153 move upward. Then, the vertical edge 165 that is substantially parallel to the moving direction of the aperture blade 153 blocks a part of the optical path sandwiched between the inclined edges 161 and 162. As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIGS. 9 (d) and 9 (e).
[0100]
The shape of the opening in this section is a shape surrounded by the stopped inclined edges 161 and 162 and the inclined edge 163 or the vertical edge 165, so that the shape is almost a hexagon. At the same time, since the ND filter 154 also moves upward, the average transmittance of the optical path passing through the light amount adjusting device is also reduced, and the amount of light incident on the image sensor 109 can be kept constant.
[0101]
In the state shown in FIG. 9E where the ND filter 154 covers the entire surface of the optical path, a regular hexagonal opening shape having substantially the same side length can be provided.
[0102]
When the illuminance of the subject further increases from the state of FIG. 9 (e), the diaphragm blade 153 stops, drives the diaphragm blades 151 and 152, moves the diaphragm blade 151 downward, and stops the diaphragm blade 152. Move up.
[0103]
As a result, the area where the inclined edge 161 and the inclined edge 162 shield the light path increases. The hexagonal opening shape surrounded by the inclined edges 161 and 162 and the vertical edge 165 is maintained until the area where the diaphragm blade 151 and the diaphragm blade 152 shield light is sufficiently large until the state shown in FIG. Can do.
[0104]
As shown in FIG. 9D, in the state immediately before the ND filter 154 covers the entire surface of the optical path, the small aperture region 115 is formed between the ND filter 154 and the inclined edge 161 of the aperture blade 151. 9 (c) to 9 (e), the diaphragm blades 151 are stopped, so that the area ratio of the small aperture region 115 occupying the entire cross-sectional area of the optical path is small, and resolution degradation is minimized. Can be suppressed. Then, as shown in FIG. 9E, after the ND filter covers the entire surface of the optical path, the diaphragm blade 153 stops, and the inclined edge 161 of the diaphragm blade 151 and the inclined edge 162 of the diaphragm blade 152 shield light. By increasing the area, the amount of light incident on the image sensor 109 can be kept constant, so that a small aperture region is not formed, and resolution does not deteriorate due to a diffraction phenomenon.
[0105]
In addition to the inclined edges 161 and 162 having an apex angle of about 120 °, light is shielded by the inclined edge 163 having an apex angle of 30 ° and the vertical edge 165, so that FIG. 9 (b) to (f) A long hexagonal opening shape can be maintained in a long section extending to. Compared with the rectangular opening shape in the prior art, in the state of FIG. 9 (e), a regular hexagonal opening shape with one side having the same length can be provided, so that a more natural blurring can be achieved. A video can be taken.
[0106]
In the third embodiment, only the case where the illuminance of the subject increases has been described. However, even when the illuminance of the subject decreases, the light amount adjustment device operates in the same manner according to the illuminance of the subject, and The amount of incident light can be kept constant.
[0107]
As described above, the light amount adjusting apparatus according to the third embodiment is configured to increase / decrease the shielding area of the optical path by the inclined edges 161, 162 of the diaphragm blades 151, 152 and increase / decrease the shielding area of the optical path by the inclined edge 163 of the diaphragm blade 153. And the illuminance of the subject from the low illuminance of the subject (corresponding to FIGS. 9 (a) to 9 (b)) due to the continuous change in the average transmittance of the light beam passing through the optical path due to the insertion and removal of the ND filter 154. Until it is high (corresponding to FIGS. 9E to 9F), the amount of light incident on the image sensor 109 can be kept constant. In addition, the aperture shape of the optical path can be kept substantially hexagonal over a wide illuminance range.
[0108]
Furthermore, since the ND filter 154 is withdrawn from the optical path when the illumination is low, there is a feature that the deterioration of the peripheral light amount ratio is small. In addition, when the illuminance of the subject is in a certain range, the diaphragm blades 151 and 152 are stopped, the increase / decrease of the shielding area of the optical path by the inclined edge 163 of the diaphragm blade 153, and the average of the light rays passing through the optical path by the insertion / extraction of the ND filter 154 Since the amount of light is adjusted by a continuous change in typical transmittance, there is a feature that there is little resolution degradation due to small aperture blur.
[0109]
Therefore, the lens barrel using this light amount adjusting device can provide a more natural blur, and the video camera and digital still camera using the lens barrel can be used for shooting high-resolution still images. Since it can shoot more natural blurred images, it can be offered to the market as a higher-quality video camera or digital still camera.
[0110]
(Embodiment 4)
FIG. 10 is a partial front view of the imaging apparatus including the light amount adjustment apparatus according to the fourth embodiment. In the fourth embodiment, the description of the same part as the description of the third embodiment is omitted.
[0111]
Since the configuration of the fourth embodiment is the same as that of the third embodiment, the operation will be described with reference to FIG. In FIG. 10, the optical axis 100 is in a direction perpendicular to the paper surface. Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0112]
First, when the illuminance of the subject is low, as shown in FIG. 10A, the diaphragm blades 153 and the ND filter 154 are retracted from the optical path, and the diaphragm blades 151 and 152 are fully opened so as not to block the optical path. When the illuminance of the subject starts to increase, the first driving unit 141 drives the diaphragm blades 151 and 152, moves the diaphragm blade 151 downward, and moves the diaphragm blade 152 upward. As a result, the area where the inclined edge 161 and the inclined edge 162 shield the light path increases.
[0113]
As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIG. At the same time, the second driving unit 143 drives the diaphragm blade 153 to move it upward. However, the inclined edge 163 of the diaphragm blade 153 moves to a position where a part of the optical path sandwiched between the inclined edges 161 and 162 is not shielded.
[0114]
Here, the peripheral light amount ratio will be described again. Depending on the optical design of the imaging optical system lens in order to provide a smaller video camera and still camera, and thus to reduce the size of the lens barrel, the minimum required even in the state shown in FIG. In some cases, the marginal peripheral light intensity ratio cannot be secured. In such a case, even if the ND filter 154 is not provided, the brightness may be different depending on the shape of the aperture opening.
[0115]
That is, the opening shape may be required to be a vertically symmetrical shape. In the fourth embodiment, even in the combination with such an imaging optical system, a vertically symmetric opening shape as shown in FIGS. In combination with the fact that the ND filter 154 is not in the optical path, it is possible to ensure a better peripheral light amount ratio.
[0116]
When the subject illuminance further increases, the diaphragm blades 151 and 152 stop, and only the diaphragm blades 153 move upward. Then, the inclined edge 163 having a narrower apex angle than the inclined edges 161 and 162 and the vertical edge 165 substantially parallel to the moving direction of the aperture blade 153 shields a part of the optical path sandwiched between the inclined edges 161 and 162. It will be. As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIGS. 10 (c) and 10 (d).
[0117]
The shape of the opening in this section is the inclined edges 161 and 162 and the inclined edge 163.
In other words, since the shape is surrounded by the vertical edge 165, the shape is almost a hexagon. At the same time, since the ND filter 154 also moves upward, the average transmittance of the optical path passing through the light amount adjusting device is also reduced, and the amount of light incident on the image sensor 109 can be kept constant.
[0118]
In the state shown in FIG. 10E where the ND filter 154 covers the entire surface of the optical path, a regular hexagonal opening shape having substantially the same side length can be provided.
[0119]
When the illuminance of the subject further increases from the state shown in FIG. 10E, the diaphragm blades 153 are stopped, the diaphragm blades 151 and 152 are driven, the diaphragm blades 151 are moved downward, and the diaphragm blades 152 are moved. Move up. As a result, the area where the inclined edge 161 and the inclined edge 162 shield the light path increases. The hexagonal opening shape surrounded by the inclined edges 161 and 162 and the vertical edge 165 is maintained until the area where the diaphragm blade 151 and the diaphragm blade 152 shield light is sufficiently large until the state shown in FIG. Can do.
[0120]
As shown in FIG. 10D, in the state immediately before the ND filter 154 covers the entire surface of the optical path, the small aperture region 115 is formed between the ND filter 154 and the inclined edge 161 of the aperture blade 151. Since the stop blade 151 is stopped from the state shown in FIGS. 10B to 10E, the area ratio of the small stop region 115 occupying the entire cross-sectional area of the optical path is small, and the deterioration of the resolution is minimized. Can be suppressed.
[0121]
Then, as shown in FIG. 10E, after the ND filter covers the entire surface of the optical path, the diaphragm blade 153 stops, and the inclined edge 161 of the diaphragm blade 151 and the inclined edge 162 of the diaphragm blade 152 shield light. By increasing the area, the amount of light incident on the image sensor 109 can be kept constant, so that a small aperture region is not formed, and resolution does not deteriorate due to a diffraction phenomenon.
[0122]
In addition to the inclined edges 161 and 162 having an apex angle of about 120 °, light is shielded by the inclined edge 163 having an apex angle of 30 ° and the vertical edge 165, so that FIGS. 10 (c) to (f) A long hexagonal opening shape can be maintained in a long section extending to. Compared to the rectangular opening shape in the prior art, in the state of FIG. 10 (e), a regular hexagonal opening shape with one side having the same length can be provided. A video can be taken.
[0123]
In the fourth embodiment, only the case where the illuminance of the subject increases has been described. However, even when the illuminance of the subject decreases, the light amount adjustment device operates in the same manner according to the illuminance of the subject, and The amount of incident light can be kept constant.
[0124]
As described above, the light amount adjusting apparatus according to the fourth embodiment increases / decreases the shielding area of the optical path by the inclined edges 161, 162 of the diaphragm blades 151, 152 and increases / decreases the shielding area of the optical path by the inclined edge 163 of the diaphragm blade 153. And the illuminance of the subject from the low illuminance of the subject (corresponding to FIGS. 10 (a) to 10 (b)) due to the continuous change in the average transmittance of the light beam passing through the optical path due to the insertion / extraction of the ND filter 154. Until it is high (corresponding to FIGS. 10E to 10F), the amount of light incident on the image sensor 109 can be kept constant. In addition, the aperture shape of the optical path can be maintained in a substantially hexagonal shape when shooting an object with a medium to high brightness where the blur is substantially noticeable. Furthermore, since the ND filter 154 is retracted from the optical path at low illuminance and the shape of the opening is symmetrical in the vertical direction, there is a feature that the deterioration of the peripheral light amount ratio is extremely small.
[0125]
In addition, when the illuminance of the subject is in a certain range, the diaphragm blades 151 and 152 are stopped, the increase / decrease of the shielding area of the optical path by the inclined edge 163 of the diaphragm blade 153, and the average of the light rays passing through the optical path by the insertion / extraction of the ND filter 154 Since the amount of light is adjusted by a continuous change in typical transmittance, there is a feature that there is little resolution degradation due to small aperture blur.
[0126]
Therefore, the lens barrel using this light amount adjusting device can provide a more natural blur, and the video camera and digital still camera using the lens barrel can be used for shooting high-resolution still images. Since it can shoot more natural blurred images, it can be offered to the market as a higher-quality video camera or digital still camera.
[0127]
(Embodiment 5)
FIG. 11 is a partial front view of the imaging apparatus including the light amount adjustment apparatus according to the fifth embodiment. In the fifth embodiment, the description of the same part as the description of the third embodiment is omitted.
[0128]
In the fifth embodiment, the ND filter 154 in the third embodiment is a liquid crystal element 157 sandwiched between transparent electrodes (not shown). Here, the liquid crystal element 157 may be a TN (Twisted Neematic) liquid crystal or a STN (SuperTN) liquid crystal using a polarizing plate.
[0129]
The operation of the light amount adjusting apparatus configured as described above will be described with reference to FIG. Also in FIG. 11, the description of the same part as the description of the third embodiment is omitted. That is, the operations in FIGS. 11A to 11E are exactly the same as those in the third embodiment.
[0130]
In the fifth embodiment, when the subject illuminance further increases from the state of FIG. 11 (e), all of the diaphragm blades 151 and 152 and the diaphragm blade 153 are stopped. Then, the transmittance of the liquid crystal element 157 is changed so that the amount of light incident on the image sensor 109 is kept constant. By changing the transmittance of the liquid crystal element 157 in this way, the opening shape can be maintained in a regular hexagon, and a better blurred image can be taken over a wider illuminance range.
[0131]
In the first to fourth embodiments, the case where the ND filter is used as the neutral density filter that changes the light transmittance has been described. However, as shown in the fifth embodiment, the first to fourth embodiments employ the ND filter. It is not limited to the case of use, and it is also possible to use an optical or electrical action as long as it has a function of attenuating light.
[0132]
For example, a polymer dispersed liquid crystal, a ferroelectric liquid crystal, an electrochromic element, or another element may be used. When these elements are used, the diaphragm blades 151 and 152 are stopped when the illuminance of the subject is high, and the transmittance is electrically variable while keeping the shielding area of the optical path by the inclined edge 163 of the diaphragm blade 153 constant. be able to. Therefore, it is possible to adjust the amount of light appropriately even when shooting a subject with higher illuminance while keeping the aperture shape close to the ideal state such as a regular hexagon. Bokeh photography is possible.
[0133]
(Embodiment 6)
FIG. 12 is a perspective view of main components of the imaging apparatus including the light amount adjustment apparatus according to the sixth embodiment. FIG. 13 is a partial front view of an imaging apparatus including the light amount adjustment apparatus in the sixth embodiment. In the sixth embodiment, description of the same parts as those in the first embodiment is omitted.
[0134]
In the sixth embodiment, the diaphragm blade 153 is provided with an inclined edge 163 having an apex angle of about 120 ° and a vertical edge 165 substantially parallel to the moving direction of the diaphragm blade 153. Then, the ND filter 154 composed of the first region 155 and the second region 156 having different transmittances is bonded and fixed at a position covering almost the entire surface of the inclined edge 163 and the vertical edge 165. The transmittance of the first region 155 is preferably 20 to 40%, for example, and the transmittance of the second region 156 is preferably about 5 to 15% lower than that of the first region 155.
[0135]
The operation of the light amount adjusting apparatus configured as described above will be described with reference to FIG.
[0136]
In FIG. 13, the optical axis 100 is in a direction perpendicular to the paper surface. Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0137]
First, the case where the illuminance of the subject is low and the illuminance is low will be described. In the case of the lowest illuminance, as shown in FIG. 13A, the diaphragm blades 153 and the ND filter 154 are retracted from the optical path, and the diaphragm blades 151 and 152 are fully opened so as not to block the optical path. When the illuminance of the subject starts to increase, the first driving unit 141 drives the diaphragm blades 151 and 152, moves the diaphragm blade 151 downward, and moves the diaphragm blade 152 upward.
[0138]
As a result, the area where the inclined edge 161 and the inclined edge 162 shield the light path increases. As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIG. At the same time, the second driving unit 143 drives the diaphragm blade 153 to move it upward. However, the inclined edge 163 of the diaphragm blade 153 moves to a position where a part of the optical path sandwiched between the inclined edges 161 and 162 is not shielded.
[0139]
When the subject illuminance further increases, the diaphragm blades 151 and 152 stop, and only the diaphragm blades 153 move upward. Then, the inclined edge 163 and the vertical edge 165 block a part of the optical path sandwiched between the inclined edges 161 and 162. As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIG. Since the shape of the opening in this section is a shape surrounded by the inclined edges 161 and 162 and the inclined edge 163 or the vertical edge 165, the shape is almost a hexagon. At the same time, since the ND filter 154 also moves upward, the average transmittance of the optical path passing through the light amount adjusting device is also reduced, and the amount of light incident on the image sensor 109 can be kept constant.
[0140]
Then, in the state of FIG. 13D where the first region 155 of the ND filter 154 covers the entire surface of the optical path, a regular hexagonal opening shape having substantially the same side length can be formed.
[0141]
When the illuminance of the subject further increases, only the aperture blade 153 moves further upward while the aperture blade 151 and the aperture blade 152 are stopped. Then, as shown in FIGS. 13E to 13F, the second region 156 of the ND filter 154 enters the optical path. In the opening shape in this section, since the inclined edges 161 and 162 are stopped, and the vertical edge 165 is parallel to the moving direction of the diaphragm blade 153, the light shielding area changes even if the diaphragm blade 153 moves. And can maintain a regular hexagonal shape. That is, it is possible to change only the average transmittance of the optical path passing through the light amount adjusting device while maintaining the regular hexagonal shape of the opening.
[0142]
As shown in FIG. 13 (c), in a state immediately before the first region 155 of the ND filter 154 covers the entire surface of the optical path, there is a small gap between the first region 155 and the inclined edge 161 of the diaphragm blade 151. Although the aperture region 115 is formed, since the aperture blade 151 is stopped from the state shown in FIGS. 13C to 13F, the area ratio of the small aperture region 115 occupying the entire cross-sectional area of the optical path is small. , Resolution degradation can be minimized.
[0143]
Similarly, as shown in FIG. 13E, in the state immediately before the second region 156 of the ND filter 154 covers the entire surface of the optical path, the second region 156 and the inclined edge 161 of the diaphragm blade 151 are between. Although the small aperture region 115 is formed, since the aperture blade 151 is stopped from the state shown in FIGS. 13C to 13F, the area ratio of the small aperture region 115 to the entire cross-sectional area of the optical path is It is small, and resolution degradation can be minimized.
[0144]
In the sixth embodiment, only the case where the illuminance of the subject increases has been described. However, even when the illuminance of the subject decreases, the light amount adjustment device operates in the same manner according to the illuminance of the subject, and The amount of incident light can be kept constant.
[0145]
As described above, the light amount adjusting apparatus according to the sixth embodiment increases / decreases the shielding area of the optical path by the inclined edges 161, 162 of the diaphragm blades 151, 152 and increases / decreases the shielding area of the optical path by the inclined edge 163 of the diaphragm blade 153. And the illuminance of the subject from the low illuminance of the subject (corresponding to FIGS. 13 (a) to (b)) due to the continuous change in the average transmittance of the light beam passing through the optical path due to the insertion / extraction of the ND filter 154. Until it is high (corresponding to FIGS. 13 (e) to (f)), the amount of light incident on the image sensor 109 can be kept constant. In addition, the aperture shape of the optical path can be kept substantially hexagonal over a wide illuminance range.
[0146]
Further, since the diaphragm blades 151 and 152 are stopped when the subject illuminance is in a certain range, there is a feature that the deterioration of the peripheral light amount ratio at the time of low illuminance is small and resolution degradation due to small aperture blur can be avoided. In addition, even when the illuminance of the subject increases, the diaphragm blades 151 and 152 are stopped, and only the second region 156 of the ND filter 154 is in the optical path while the light shielding area by the diaphragm blade 153 is kept constant. Since the transmittance of the optical path can be changed by entering the lens, it is possible to provide a regular hexagonal opening shape having substantially the same side length near the ideal state even for a subject with higher brightness.
[0147]
Therefore, the lens barrel using this light amount adjusting device can provide a more natural blur, and the video camera and digital still camera using the lens barrel can be used for shooting high-resolution still images. Since it can shoot more natural blurred images, it can be offered to the market as a higher-quality video camera or digital still camera.
[0148]
(Embodiment 7)
FIG. 14 is a partial front view of an imaging apparatus including the light amount adjustment apparatus according to the seventh embodiment. In the seventh embodiment, the description of the same part as the description of the sixth embodiment is omitted.
[0149]
Since the configuration of the seventh embodiment is the same as that of the sixth embodiment, the operation will be described with reference to FIG. In FIG. 14, the optical axis 100 is in a direction perpendicular to the paper surface. Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0150]
First, the case where the illuminance of the subject is low and the illuminance is low will be described. In the case of the lowest illuminance, as shown in FIG. 14A, the diaphragm blades 153 and the ND filter 154 are retracted from the optical path, and the diaphragm blades 151 and 152 are fully opened so as not to block the optical path.
[0151]
When the illuminance of the subject starts to increase, the first driving unit 141 drives the diaphragm blades 151 and 152, moves the diaphragm blade 151 downward, and moves the diaphragm blade 152 upward. As a result, the area where the inclined edge 161 and the inclined edge 162 shield the light path increases.
[0152]
As a result, the cross-sectional area of the optical path passing through the light amount adjusting device decreases as shown in FIG. At the same time, the second driving unit 143 drives the diaphragm blade 153 to move it upward.
[0153]
However, the inclined edge 163 of the diaphragm blade 153 moves to a position where a part of the optical path sandwiched between the inclined edges 161 and 162 is not shielded.
[0154]
Here, when the stop positions of the diaphragm blades 151 and 152 in FIG. 14 (b) are compared with those in FIG. 13 (b), the optical path surrounded by the inclined edges 161 and 162 is smaller in FIG. 14 (b). You can see that
[0155]
Here, the depth of field will be described. When taking a picture, for example, when focusing on the subject, there is a range where the subject can be considered to be in focus before and after the subject. This range is called “depth of field”. In general, the smaller the aperture, the deeper the depth of field, and even if the position of the subject is shifted, it is possible to perform shooting in a good focus state.
[0156]
In particular, high-grade video cameras and digital still cameras often have various shooting modes in order to improve the convenience of the photographer. For example, when shooting a moving subject, it is better that the depth of field is deeper so that the subject can be shot without being blurred even if the focus position is shifted. In such a case, since the depth of field has priority over the blur, it is desirable to shoot in a state that is as narrow as possible.
[0157]
The seventh embodiment meets such a demand. That is, since the diaphragm blades 151 and 152 are driven while the ND filter 154 is retracted outside the optical path from the state shown in FIG. It is possible to shoot in the most narrowed state. In other words, in the sixth embodiment, the amount of incident light on the image sensor 109 is adjusted by reducing the transmittance by the ND filter 154 from the state of FIG. In the seventh embodiment, since the light amount is adjusted only by the diaphragm blades 151 and 152 without using the ND filter 154 at all, photographing is performed in the most narrowed state, that is, in the deepest depth of field. Can do.
[0158]
When the subject illuminance further increases from the state of FIG. 14B, the diaphragm blades 151 and 152 stop, and only the diaphragm blades 153 move upward. At this time, since the width of the opening formed by the inclined edges 161 and 162 is sufficiently small in the state of FIG. 14B, not only the inclined edge 163 but also the vertical edge 165 blocks a part of the optical path. There is nothing to do. However, since the ND filter 154 also moves upward, the average transmittance of the optical path passing through the light amount adjusting device is reduced, and the light amount incident on the image sensor 109 can be kept constant.
[0159]
That is, in the state of FIG. 14 (b), since a sufficient depth of field is obtained, it is preferable that the light shielding area by the diaphragm blades 151 and 152 and the diaphragm blade 153 does not increase any more. This is because when the light-shielding area is further increased, the resolution may be deteriorated due to small aperture blur. For this reason, the position where the diaphragm blades 151 and 152 are stopped is important. That is, the diaphragm blades 151 and 152 may be stopped at a position where light cannot be blocked by the diaphragm blade 153 substantially. The state of FIG. 14B is a position that satisfies this condition.
[0160]
Although the seventh embodiment has been described only in the case where the illuminance of the subject increases, the light amount adjustment device operates in the same manner according to the illuminance of the subject even when the illuminance of the subject decreases.
[0161]
As described above, the light amount adjusting device according to the seventh embodiment is an average of the light beam passing through the optical path due to the increase / decrease of the shielding area of the optical path by the inclined edges 161, 162 of the diaphragm blades 151, 152 and the ND filter 154 being put in and out. Due to the continuous change in the transmittance, from low illuminance of the subject (corresponding to FIGS. 14 (a) to (b)) to high illuminance of the subject (corresponding to FIGS. 14 (e) to (f)). The amount of light incident on the image sensor 109 can be kept constant.
[0162]
In addition, the diaphragm blades 151 and 152 are stopped at a position where the optical path cannot be substantially blocked by the diaphragm blade 153, and the diaphragm blade 153 is driven according to the change in the illuminance of the subject. The average transmission of the optical path by the ND filter 154 The amount of light passing through the optical path can be adjusted by continuously changing the rate. As a result, it is possible to shoot with the deepest depth of field.
[0163]
Therefore, in a lens barrel using this light amount adjusting device, it is possible to shoot with a deeper depth of field. Since the configuration of the seventh embodiment is the same as that of the sixth embodiment, the operation described in the sixth embodiment can also be performed. That is, the user can select and use the first shooting mode for obtaining a more natural bokeh and the second shooting mode giving priority to the depth of field. It can be offered to the market as a digital still camera.
[0164]
(Embodiment 8)
FIG. 15 is a partial front view of an imaging apparatus including the light amount adjustment apparatus according to the eighth embodiment. In the eighth embodiment, the description of the same part as the description of the sixth embodiment is omitted.
[0165]
Since the configuration of the eighth embodiment is the same as that of the sixth embodiment, the operation will be described with reference to FIG. In FIG. 15, the optical axis 100 is in a direction perpendicular to the paper surface. Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0166]
First, the difference in operation of the light amount adjustment device between moving image shooting and still image shooting will be described. When shooting a moving image, in order to smoothly record the movement of the subject, for example, it is necessary to continuously record the video in synchronization with frames at intervals of 1/60 seconds.
[0167]
For this reason, it is necessary for the light amount adjusting device to smoothly follow the change in subject illuminance. Further, the light accumulation time of the image sensor 109 is normally a fixed time of 1/60 seconds, and the smooth movement of the subject can be reproduced as a moving image.
[0168]
On the other hand, at the time of still image shooting, it is only necessary to capture a video for a moment. Therefore, unlike moving image shooting, it is often undesirable to blur the image due to movement of the subject or camera shake of the photographer. Therefore, at the time of still image shooting, it is usual to perform a mechanical shutter operation using a light amount adjusting device or a shutter device. The operation is as follows.
[0169]
When a photographer presses a shutter button (not shown), the light amount control unit 110 calculates an optimal aperture position and a shutter time at which the exposure time of the image sensor 109 is optimal in accordance with subject illuminance. Then, the first driving unit 141 and the second driving unit 143 drive the diaphragm blades 151 and 152 and the diaphragm blade 153 to fix them at the optimum diaphragm position.
[0170]
Then, when the light accumulation operation by the image sensor 109 is started and eventually the predetermined shutter time calculated earlier is reached, the first drive unit 141 drives the diaphragm blades 151 and 152 to perform a mechanical shutter operation to fully close it. It is. In this way, by adjusting the time from the start of the light accumulation operation by the image sensor 109 until the diaphragm blades 151 and 152 are suddenly moved to the fully closed state, the exposure time of the image sensor 109 is made appropriate. can do. The output of the image sensor 109 is proportional to the product of the amount of light incident on the image sensor 109 and its exposure time. Therefore, even if the amount of light varies, the output of the image sensor 109 can be kept constant by appropriately adjusting the exposure time.
[0171]
During movie shooting, the exposure time was fixed at, for example, 1/60 seconds in order to reproduce the smooth movement of the subject, so it was necessary to always keep the amount of light incident on the image sensor 109 constant. At the time of image shooting, the exposure time may be adjusted by a mechanical shutter operation.
[0172]
In the eighth embodiment, it is possible to provide a better image quality and a better degree of blur by combining this mechanical shutter operation. The operation will be described below.
[0173]
First, the case where the illuminance of the subject is low and the illuminance is low will be described. In the case of the lowest illuminance, as shown in FIG. 15A, the diaphragm blade 153 and the ND filter 154 are retracted from the optical path, and the diaphragm blades 151 and 152 are fully opened so as not to block the optical path. Even when the illuminance of the subject starts to increase, the diaphragm blades 151 and 152 and the diaphragm blade 153 are stopped, and the exposure time is adjusted by shortening the shutter time in the mechanical shutter operation. In the mechanical shutter operation, the shutter time can be adjusted from 1/60 seconds, which is equivalent to the time of moving image shooting, to about 1/500 seconds, for example. This can be done without moving the 152 and the diaphragm blade 153.
[0174]
Further, when the illuminance of the subject increases, it is no longer possible to cope with changes in the illuminance of the subject simply by adjusting the shutter speed. Therefore, the aperture blades 151 and 152 and the aperture 153 are intermittently operated to stop at the position shown in FIG. . As a result, the area where the inclined edge 161 and the inclined edge 162 block the light path is increased, so that the amount of light incident on the image sensor 109 can be reduced. Therefore, the shutter speed can be returned to the longest 1/30 second.
[0175]
Further, even if the subject illuminance increases, the exposure time is adjusted by shortening the shutter time in the mechanical shutter operation. Similarly, when the illuminance of the subject increases, the diaphragm blades 151 and 152 and the diaphragm blade 153 are intermittently operated to stop at the positions shown in FIGS. 15 (c) and 15 (d). Then, the exposure time is adjusted by shortening the shutter time in the mechanical shutter operation while stopping the diaphragm blades at each position.
[0176]
As described above, in the eighth embodiment, by combining the intermittent operation of the aperture blades 151 and 152 and the aperture blade 153 and the mechanical shutter operation, the aperture shape at the time of still image shooting is shown in FIGS. It can be fixed in any of the states shown in d). Here, by looking at the shape of the aperture opening in FIGS. 15A and 15B, it can be seen that the ND filter 154 does not protrude from the opening at all. 15C shows a state in which the first region 155 of the ND filter 154 covers the entire opening, and FIG. 15D shows a state in which the second region 156 of the ND filter 154 covers the entire opening. The state is fixed. That is, the stop blade 153 is stopped at a position where the transmittance by the ND filter 154 is uniform in a cross section perpendicular to the optical path. As a result, no small aperture region is generated, so that the resolution is not deteriorated at all. In addition, the shape of the aperture opening is symmetric in the vertical and horizontal directions, and the transmittance by the ND filter 154 is uniform in the cross section, so that an excellent blurred image can be taken.
[0177]
In the eighth embodiment, only the case where the illuminance of the subject increases has been described. However, even when the illuminance of the subject decreases, the light amount adjustment device operates in the same manner according to the illuminance of the subject.
[0178]
As described above, the light amount adjusting apparatus according to the eighth embodiment intermittently drives the diaphragm blades 151 and 152 and the diaphragm blade 153 and also uses the mechanical shutter operation, so that the illuminance of the subject is low and low (see FIG. 15 (a)) to when the subject illuminance is high (corresponding to FIG. 15 (d)), the output of the image sensor 109 can be kept in an appropriate state.
[0179]
In addition, since the diaphragm blades 153 are stopped at a plurality of positions where the transmittance by the ND filter 154 is uniform in a cross section perpendicular to the optical path, the small diaphragm region does not occur and the resolution does not deteriorate at all. In addition, the shape of the aperture opening is symmetric in the vertical and horizontal directions, and the transmittance by the ND filter 154 is uniform in the cross section, so that an excellent blurred image can be taken. Since the configuration of the eighth embodiment is the same as that of the sixth embodiment, the operation described in the sixth embodiment can be performed.
[0180]
That is, when the light accumulation time of the image sensor 109 is a fixed time as in moving image shooting, the light amount adjustment device smoothly follows the change in subject illuminance by performing the operation of the sixth embodiment. It is also possible to make it. At the time of still image shooting, by performing the operation of the eighth embodiment, it is possible to capture an image with higher resolution and excellent blur. Therefore, since two kinds of operation states can be selectively implemented according to the user's photographing purpose, it can be provided to the market as a higher-grade video camera or digital still camera.
[0181]
In the eighth embodiment, the light accumulation time of the image sensor 109 is adjusted by a mechanical shutter operation. However, this may be adjusted by a known electronic shutter operation of the image sensor 109. In this case, there is no need to drive the diaphragm blades 151 and 152, and this method is suitable for taking still images continuously. Furthermore, the electronic shutter operation and the mechanical shutter operation may be used together. In this case, image quality deterioration factors such as smear can be eliminated, and a more beautiful still image can be taken.
[0182]
In the eighth embodiment, the mechanical shutter operation is performed using the aperture blades 151 and 152. However, a shutter device may be provided separately. In this case, since the shutter device optimum for the mechanical shutter operation is used, the shutter time can be further shortened and a subject with a wider illuminance can be handled.
[0183]
Alternatively, not only the diaphragm blades 151 and 152 but also the diaphragm blade 153 may be driven to perform the mechanical shutter operation using the three diaphragm blades. In this case, since the aperture shape during the mechanical shutter operation can be made to be a more circular shape, a still image with better blur can be taken.
[0184]
(Embodiment 9)
FIG. 16 is a perspective view of main components of an imaging apparatus including the light amount adjustment apparatus according to the ninth embodiment. FIG. 17 is a partial front view of an imaging apparatus including the light amount adjustment apparatus according to the ninth embodiment. In the ninth embodiment, the description of the same part as the description of the sixth embodiment is omitted. In the ninth embodiment, the diaphragm blade 153 is provided with a second vertical edge 166 that is narrower than the vertical edge 165.
[0185]
The operation of the light amount adjusting apparatus configured as described above will be described with reference to FIG. In the ninth embodiment, as in the eighth embodiment, the mechanical shutter operation is also used. In FIG. 17, the optical axis 100 is in a direction perpendicular to the paper surface. Here, in order to simplify the description, the operation of the light amount adjusting device will be described in the case where the illuminance of the subject increases little by little.
[0186]
First, the case where the illuminance of the subject is low and the illuminance is low will be described. In the case of the lowest illuminance, as shown in FIG. 17A, the diaphragm blades 153 and the ND filter 154 are retracted from the optical path, and the diaphragm blades 151 and 152 are fully opened so as not to block the optical path. Even when the illuminance of the subject starts to increase, the diaphragm blades 151 and 152 and the diaphragm blade 153 are stopped, and the exposure time is adjusted by shortening the shutter time in the mechanical shutter operation. In the mechanical shutter operation, the shutter time can be adjusted from 1/60 seconds, which is equivalent to the time of moving image shooting, to about 1/500 seconds, for example. This can be done without moving the 152 and the diaphragm blade 153.
[0187]
Further, when the subject illuminance increases, the change in the subject illuminance can no longer be accommodated only by adjusting the shutter speed, so the diaphragm blades 151 and 152 and the diaphragm 153 are intermittently operated to stop at the position shown in FIG. . As a result, the area where the inclined edge 161 and the inclined edge 162 block the light path is increased, so that the amount of light incident on the image sensor 109 can be reduced. Therefore, the shutter speed can be returned to the longest 1/30 second.
[0188]
Further, even if the subject illuminance increases, the exposure time is adjusted by shortening the shutter time in the mechanical shutter operation. Similarly, when the illuminance of the subject increases, the diaphragm blades 151 and 152 and the diaphragm blade 153 are intermittently operated to stop at the positions shown in FIGS. 17 (c) and (d). Then, the exposure time is adjusted by shortening the shutter time in the mechanical shutter operation while stopping the diaphragm blades at each position.
[0189]
Further, in the ninth embodiment, since the second vertical edge 166 that is narrower than the vertical edge 165 is provided, the diaphragm blades 151 and 152 and the diaphragm 153 are operated intermittently when the illuminance of the subject increases. To stop at the position shown in FIG.
[0190]
In the state shown in FIG. 17 (e), the transmittance by the ND filter 154 is the same as that in FIG. 17 (d), but the shape of the aperture is substantially a regular hexagon similar to FIG. 17 (d). Thus, the area of the opening can be further reduced. That is, even for a subject with higher illuminance, the shape of the aperture opening is symmetrical in the vertical and horizontal directions, and the transmittance by the ND filter 154 is uniform in the cross section, so that an excellent blur image can be taken. Can do.
[0191]
Here, comparing the aperture opening in FIGS. 17A, 17B, 17C, and 17D with that in FIG. 15, it can be seen that the aperture shape is exactly the same. In the ninth embodiment, the diaphragm blade 153 is provided with the second vertical edge 166 that is narrower than the vertical edge 165. However, in the operation state shown in FIGS. It can be seen that the edge 166 has no influence. That is, in the ninth embodiment, the same operation as in the sixth embodiment can be performed. In the ninth embodiment, only the case where the illuminance of the subject is increased is described. Even when the illuminance decreases, the light amount adjusting device operates in the same manner according to the illuminance of the subject.
[0192]
As described above, the light amount adjusting apparatus according to the ninth embodiment performs intermittent driving of the diaphragm blades 151 and 152 and the diaphragm blade 153 and also uses the mechanical shutter operation, so that the illuminance of the subject is low and low (see FIG. 17 (a)) to when the subject illuminance is extremely high (corresponding to FIG. 17 (e)), the output of the image sensor 109 can be kept in an appropriate state.
[0193]
In addition, since the diaphragm blades 153 are stopped at a plurality of positions where the transmittance by the ND filter 154 is uniform in a cross section perpendicular to the optical path, the small diaphragm region does not occur and the resolution does not deteriorate at all.
[0194]
In addition, the shape of the aperture opening is symmetric in the vertical and horizontal directions, and the transmittance by the ND filter 154 is uniform in the cross section, so that an excellent blurred image can be taken. Further, since the transmittance by the ND filter 154 is the same, the diaphragm blades 151 and 152 and the diaphragm blade 153 can be stopped at positions where the light shielding areas are different, and the shape of the opening can be made similar. In addition, it is possible to shoot a subject with an appropriate exposure condition even for a subject with high illuminance.
[0195]
Further, since the configuration of the ninth embodiment is almost the same as that of the sixth embodiment, the operation described in the sixth embodiment can also be performed. That is, when the light accumulation time of the image sensor 109 is a fixed time as in moving image shooting, the light amount adjustment device smoothly follows the change in subject illuminance by performing the operation of the sixth embodiment. It is also possible to make it.
[0196]
At the time of still image shooting, by performing the operation of the ninth embodiment, it is possible to capture a higher resolution and better blurred image for a wider range of subject illuminance. Therefore, since two kinds of operation states can be selectively implemented according to the user's photographing purpose, it can be provided to the market as a higher-grade video camera or digital still camera.
[0197]
【The invention's effect】
As described above, according to the light amount adjusting device and the imaging device of the present invention, an effect that preferable blurring of an image can be obtained. Further, there is an effect that there is little deterioration in resolution due to diffraction when performing light amount adjustment.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a perspective view of main components of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a partial front view of the image pickup apparatus including the light amount adjustment apparatus according to the first embodiment of the present invention, in which (a) is a fully open state, and the aperture is reduced as (b) to (e) are reached. Figure showing
4A is a partial front view showing an imaging apparatus including a light amount adjustment apparatus according to Embodiment 1 of the present invention. FIG.
(B) Partial front view showing an operation comparison of an imaging device including a light amount adjustment device according to the prior art
FIG. 5 is a perspective view of main components of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 2 of the present invention.
6 is a partial front view of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 2 of the present invention, in which (a) is a fully opened state, and the aperture is reduced as (b) to (e). Figure showing
FIG. 7 (a) is a partial front view showing a state in which the imaging apparatus including the light amount adjusting apparatus according to the second embodiment of the present invention is fully opened.
(B) The partial front view which shows the state at the time of full closure of the imaging device containing the light quantity adjustment apparatus by Embodiment 2 of this invention
FIG. 8 is a perspective view of main components of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 3 of the present invention.
FIG. 9 is a partial front view of an imaging apparatus including a light amount adjustment apparatus according to a third embodiment of the present invention, in which (a) is a fully open state, and the aperture is reduced as (b) to (f). Figure showing
FIG. 10 is a partial front view of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 4 of the present invention, in which (a) is a fully open state, and the aperture is reduced as (b) to (f). Figure showing
FIG. 11 is a partial front view of an imaging apparatus including a light amount adjustment apparatus according to a fifth embodiment of the present invention, in which (a) is a fully open state, and the aperture is reduced as (b) to (f). Figure showing
12 is a perspective view of main components of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 6 of the present invention. FIG.
FIG. 13 is a partial front view of an imaging apparatus including a light amount adjustment apparatus according to Embodiment 6 of the present invention, in which (a) is a fully open state, and the aperture is reduced as (b) to (f). Figure showing
14 is a partial front view of an imaging apparatus including a light amount adjustment apparatus according to a seventh embodiment of the present invention, in which (a) is a fully open state, and the aperture is reduced as (b) to (f). Figure showing
FIG. 15 is a partial front view of an imaging apparatus including a light amount adjustment apparatus according to an eighth embodiment of the present invention, in which (a) is a fully open state and the aperture is reduced as (b) to (d) are reached; Figure showing
FIG. 16 is a perspective view of main components of an imaging apparatus including a light amount adjustment apparatus according to a ninth embodiment of the present invention.
FIG. 17 is a partial front view of an image pickup apparatus including a light amount adjustment apparatus according to a ninth embodiment of the present invention, in which (a) is a fully open state, and the aperture is reduced as it becomes (b) to (e); Figure showing
FIG. 18 is a block diagram illustrating a configuration of an imaging apparatus including a conventional light amount adjustment apparatus.
FIG. 19 is a perspective view of main components of an imaging apparatus including a conventional light amount adjustment device.
FIG. 20 is a partial front view of an image pickup apparatus including a conventional light amount adjustment device, in which (a) shows a fully open state, and shows a state in which an aperture is reduced as (b) to (f).
[Explanation of symbols]
1 base
2 First meter
3 Rotor
4 Second meter
5 arm
100 optical axes
108 Video signal processing circuit
109 Image sensor
110 Light quantity controller
115 Small aperture area
121 Front lens group
122 Zoom lens group
123 Correction lens group
124 Focus lens group
141 1st drive part
142 1st detection part
143 Second drive unit
144 Second detection unit
151, 152, 153
154 ND filter
155 first region
156 second region
157 Liquid crystal element
161, 162, 163 Inclined edge
164 Horizontal edge
165 vertical edge
166 Second vertical edge

Claims (12)

A light amount adjusting device provided in an imaging optical system for forming a subject image,
A plurality of first aperture blades capable of increasing or decreasing the shielding area of the optical path;
A neutral density filter that is driven by a driving means different from the driving means for driving the first diaphragm blades, and is capable of changing the transmittance of light passing through the optical path by being taken in and out of the optical path;
A second diaphragm blade that operates integrally with the neutral density filter, can increase or decrease the shielding area of the optical path , and shields the intersection of the edges on the opening side of the plurality of first diaphragm blades. ,
Increasing / decreasing the shielding area of the optical path by the plurality of first diaphragm blades, increasing / decreasing the shielding area of the optical path by the second diaphragm blades , and shielding the intersection of the edges on the opening side of the plurality of first diaphragm blades A light amount adjusting device that adjusts the amount of light passing through the optical path by combining with a change in transmittance due to insertion and removal of the neutral density filter. A first driving means for moving the first diaphragm blade into and out of the optical path;
Second driving means for taking the second diaphragm blade into and out of the optical path;
When the subject illuminance is in the first illuminance range, the first diaphragm blade is stopped, and the second driving means drives the second diaphragm blade according to the change in the subject illuminance, and While increasing or decreasing the shielding area of the optical path by the second aperture blade,
The light amount adjusting device according to claim 1, wherein the light amount passing through the optical path is adjusted by a change in transmittance by the neutral density filter that operates integrally with the second diaphragm blade.   When the subject illuminance is in the second illuminance range higher than the first illuminance range, the second diaphragm blade is maintained while keeping the shielding area of the optical path by the second diaphragm blade constant according to the change in the subject illuminance. The light amount adjusting device according to claim 2, wherein the light amount passing through the optical path is adjusted by a change in transmittance by a neutral density filter that operates integrally with the light amount filter. First driving means for moving the first aperture blade into and out of the optical path;
Second driving means for taking the second diaphragm blade into and out of the optical path;
When the illuminance of the subject is in the first illuminance range, the first diaphragm blade is stopped, and the transmittance of the neutral density filter is uniform at a plurality of positions in a cross section perpendicular to the optical path. The light quantity adjusting device according to claim 1, wherein the diaphragm blade is stopped and the light quantity passing through the optical path is adjusted. When the subject illuminance is in the second illuminance range higher than the first illuminance range, the first driving means drives the first diaphragm blade, and the second driving means is the second illuminance range.
The transmittance by the neutral density filter is uniform in a cross section perpendicular to the optical path, and the shielding area of the optical path by the first diaphragm blade and the second diaphragm blade is the first. The light quantity adjusting device according to claim 4, wherein the first diaphragm blade and the second diaphragm blade are stopped at a position that increases together with a light shielding area in the illuminance range.   2. A first detection unit for detecting a position of the first diaphragm blade, wherein the first diaphragm blade is positioned in accordance with an output of the first detection unit. 5. The light amount adjusting device according to any one of 5 above.   A second detection unit configured to detect a position of the second diaphragm blade, wherein the second detection unit and the output of the second detection unit have a predetermined relationship between the second detection unit and the second detection unit; The light quantity adjusting device according to claim 6, wherein the aperture blade is positioned. A light amount adjusting device according to any one of claims 1 to 7,
An imaging optical system for forming a subject image;
A lens barrel. A light amount adjusting device according to any one of claims 1 to 7,
An imaging optical system for forming a subject image;
An image pickup apparatus having an image pickup element that receives an image of a formed subject.   10. The imaging apparatus according to claim 9, wherein a mechanical shutter operation is performed by fully closing the optical path with the first diaphragm blades in response to a user's still image shooting instruction.   The image pickup apparatus according to claim 9, wherein a mechanical shutter operation is performed by fully closing an optical path with the first diaphragm blade and the second diaphragm blade in response to a user's still image photographing instruction.   The image pickup apparatus according to claim 9, wherein an exposure time accumulated by the image pickup device is determined in accordance with a user's still image shooting instruction, and a light storage time of the image pickup device is made variable.

Images