JP3798821B2 - Rotation color filter - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a rotary color filter that is provided in a color imaging device and is disposed to face a light receiving portion of an imaging element.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an imaging device provided in an electronic camera, a video camera, or the like that can reproduce a color image, an imaging device in which a rotating color filter for color separation is provided on the light receiving unit side of an imaging element is known. According to the configuration having this rotating color filter, the pixels of the image sensor can be used effectively, and there is no false color problem that occurs when the filter array method is used, and the color signal is extracted independently. Are better.
[0003]
[Problems to be solved by the invention]
Incidentally, a dark current is generated in the image sensor in proportion to the temperature. The dark current is generally generated in the photosensitive portion and the storage portion in a state where light is not incident on the photosensitive portion of the image pickup device, and thereby white scratch-like noise is generated on the photographed screen. Particularly when the exposure time is long, the dark current tends to increase. In order to remove the influence of this dark current, the image sensor may be cooled. However, if a new cooling device is provided, the size of the imaging device main body will be increased by the amount of this device, and the manufacturing cost will increase.
[0004]
The present invention provides a rotating color filter that cools the image sensor and removes the influence of dark current generated in the image sensor. As a result, the color imaging device main body including the rotating color filter is reduced in size and manufactured at low cost. The purpose is to reduce costs.
[0005]
[Means for solving problems]
A rotational color filter according to the present invention includes a plurality of color filter elements rotatably provided so as to cross the front side of the image sensor, and a driving unit that rotationally drives the plurality of color filter elements. An air flow is sent out to the image sensor by rotation of the filter element.
[0006]
[Action]
The plurality of color filter elements are rotationally driven by the driving means. The rotation of the plurality of color filter elements sends an air flow toward the image sensor, and the image sensor is cooled.
[0007]
【Example】
The present invention will be described below with reference to illustrated embodiments.
1 and 2 are perspective views showing a configuration of a main part of a rotary color filter according to an embodiment of the present invention.
[0008]
Incident light that has passed through the imaging lens 10 passes through one of the color filter elements 21, 22, and 23 and is guided to the light receiving unit of the imaging device (CCD) 11, and a subject image is formed on the light receiving unit. The CCD 11 is driven by a drive circuit (not shown), whereby a pixel signal corresponding to the subject image is read from the CCD 11.
[0009]
The DC motor 26 is a drive source for rotationally driving the color filter elements 21 to 23, and is driven by control of a system control circuit (not shown). The DC motor 26 has rotating shafts 31 and 32 extending on both sides along the axis. An annular support member 24 is fitted on the rotary shaft 31, and an encoder 27 is provided on the rotary shaft 32. A fan-shaped G (green) filter element 21, R (red) filter element 22, and B (blue) filter element 23 are provided on the outer peripheral surface of the support member 24, and each of these color filter elements 21, 22, 23 is It is located between the imaging lens 10 and the CCD 11.
[0010]
Three cutouts 28 are formed at equal intervals in the outer peripheral edge of the encoder 27, and a photo interrupter 29 is disposed in the vicinity of the outer peripheral edge. The photo interrupter 29 is a sensor composed of a pair of generating elements and light receiving elements, and outputs a detection signal to the system control circuit every time the notch 28 passes. The system control circuit controls the rotational phase and the like of the rotational color filter based on the detection signal.
[0011]
The color filter elements 21, 22, and 23 are arranged at positions twisted with respect to the plane perpendicular to the rotation axis, and are provided at equal intervals around the rotation axis. The rotation axis 31 is determined so as to be positioned substantially parallel to the CCD 11 when the color filter elements 21, 22, and 23 cross the front side of the CCD 11, that is, at a position twisted with respect to the optical axis of the imaging lens 10. That is, the incident light beam enters the color filter elements 21, 22, and 23 and the light receiving surface of the CCD 11 perpendicularly. The color filter elements 21, 22, and 23 are formed in shapes that do not overlap each other when viewed from the direction of the rotation shafts 31 and 32.
[0012]
Next, the operation of the rotating color filter of this embodiment will be described with reference to FIGS. When the release switch of the operation unit is pressed, the DC motor 26 is driven under the control of the system control circuit. The DC motor 26 rotates each color filter element 21, 22, 23 in the direction of arrow A in FIG. The color filter elements 21, 22, and 23 are sequentially positioned substantially in parallel on the CCD 11. While each color filter element 21, 22, 23 faces the CCD 11, a pixel signal corresponding to each color is generated on the CCD 11 and read out from the CCD 11 at a predetermined timing.
[0013]
The rotational speed of the DC motor 26 is appropriately determined from the drive timing of the CCD 11 corresponding to the frame sequential scanning imaging method.
[0014]
An air flow is sent in the direction of the CCD 11 by the rotation of the color filter elements 21, 22, and 23. As a result, the CCD 11 is cooled, and the amount of dark current generated in the CCD 11 is kept low.
[0015]
As described above, according to the rotating color filter of this embodiment, the influence of the dark current generated in the CCD 11 is removed by cooling the CCD 11 using the rotation of the color filter elements 21, 22, and 23. Therefore, it is not necessary to separately provide a cooling device in the imaging apparatus body, so that the imaging apparatus body can be reduced in size and the manufacturing cost can be reduced.
[0016]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a rotating color filter that cools the image sensor and removes the influence of the dark current generated in the image sensor. As a result, the color imaging device main body including the rotating color filter can be reduced in size. And manufacturing costs can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a rotary color filter according to a first embodiment of the present invention.
FIG. 2 is a perspective view of the rotating color filter of FIG.
[Explanation of symbols]
11 CCD (imaging device)
21, 22, 23 Color filter element 24 Support member 26 DC motor 31, 32 Rotating shaft

Claims (2)

It is provided so as to be rotatable so as to cross the front side of the image sensor and to be twisted with respect to a plane perpendicular to the rotation axis, and substantially parallel to the image sensor when traversing the front side of the image sensor. A plurality of color filter elements positioned at the same position and a driving means for rotationally driving the plurality of color filter elements, and the rotation of the plurality of color filter elements causes an air flow to be sent to the imaging device. Color filter.   The rotating color filter according to claim 1, wherein each color filter element has a sector shape.

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