JP2008187265A - Image-shiftable cooling camera - Google Patents

Abstract

An image shiftable cooling camera that enables cooling of an image sensor and driving of an image shift means within a predetermined allowable current is provided.
An image pickup device, a cooling device for cooling the image pickup device, an image shift means for shifting a light beam incident on the image pickup device within a plane of the image pickup device, and the image shift means. The image-shiftable cooling camera 1 includes a driving unit 27 that drives the driving unit 23, and includes a control unit 9 that controls a current supplied to the driving unit 27 and a current supplied to the cooling element 5 within an allowable current.
[Selection] Figure 1

Description

  The present invention relates to a cooling camera having an image shift function.

Conventionally, in an imaging device using an imaging device (for example, CCD, CMOS, etc.), the relative position between an image and the imaging device is slightly shifted (also referred to as pixel shifting), and an image at each position is acquired. Cooling camera capable of image shift (pixel shift) that increases the number of apparent pixels and cools the image sensor with a cooling element such as a Peltier element to reduce dark current noise of the image sensor and acquire a high-resolution image Is known (see, for example, Patent Document 1).
JP 2004-129583 A

  However, in the conventional image-shiftable cooling camera, the current when the image shift means for shifting the image incident on the image sensor is driven while supplying the current to the Peltier element to cool the image sensor becomes excessive. There is a problem that the allowable current of the cooling camera capable of image shift is exceeded.

  In order to solve the above problems, the present invention provides an image sensor, a cooling element that cools the image sensor, an image shift unit that shifts a light beam incident on the image sensor in a plane of the image sensor, and the image shift. An image-shiftable cooling camera comprising: drive means for driving means; and control means for controlling current supplied to the drive means and current supplied to the cooling element within an allowable current. provide.

  According to the present invention, it is possible to provide an image-shiftable cooling camera that enables cooling of an image sensor and driving of an image shift means within a predetermined allowable current.

  An image-shiftable cooling camera according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration block diagram of a cooling camera capable of image shifting according to the present embodiment.

  In FIG. 1, an image shiftable cooling camera 1 (hereinafter simply referred to as a camera) includes an image sensor 3 (for example, CCD, CMOS, etc.) that captures a subject image formed via an optical system (not shown), A Peltier element 5 that is in thermal contact with the image sensor 2 to cool the image sensor 3, an image shift device 7 that shifts the formed subject image within the plane of the image sensor 3, and a control device 9 that controls them. It consists of

  The image pickup device 3 is driven and controlled from the control device 9 via the image pickup device driver 11, picks up the formed subject image, is processed by the image processing circuit 13, and is displayed on the monitor 15. In addition, data is stored in a memory (not shown).

  A Peltier element 5 is thermally connected to the image sensor 3, and a heat sink 17 for heat dissipation is in thermal contact with the surface of the Peltier element 5 facing the image sensor 3. The heat generated from the Peltier element 5 is transmitted to the heat sink 17 and released into the air.

  A temperature sensor 19 for detecting the temperature of the image sensor 3 in contact with the image sensor 3 is disposed. Temperature information from the temperature sensor 19 is sent to the control device 9 and used for temperature control of the image sensor 3.

  The Peltier device 5 is connected to the control device 9 via the Peltier driver 21, and the control device 9 sends a signal to the Peltier driver 21 based on temperature information from the temperature sensor 19, and generates a current to be applied from the Peltier driver 21 to the Peltier device 5. The cooling temperature of the Peltier element 5 is controlled to finally control the temperature of the image sensor 3. Thereby, the temperature of the image sensor 3 set by the user in the control device 9 is automatically controlled, and the image sensor 3 can be maintained at a substantially constant temperature.

  The image shift device 7 includes a parallel plate glass 23 for shifting an incident light beam, a cam ring 25 having a cam for inclining the parallel plate glass 23 with respect to the optical axis, and a rotation for rotating the cam ring 25. The motor 27 is configured.

  The motor 27 is driven via a motor driver 29 based on a control signal from the control device 9, and is connected to a cam ring 27 via a gear 27 a provided on the rotating shaft of the motor 27 and a gear 25 a provided on the outer periphery of the cam ring 27. Is rotated to a predetermined position, and the parallel flat glass 23 is inclined at a predetermined angle with respect to the optical axis by the action of the cam formed on the cam ring 25. Due to this inclination angle, the light beam incident on the parallel flat glass 23 is shifted by a predetermined amount in a predetermined direction with respect to the optical axis, emitted, and incident on the image sensor 3 to shift the image on the surface of the image sensor 3. Is possible.

  The motor 27 is a pulse motor, and a constant amount of current is constantly applied to maintain the rotational position of the cam ring 25. In this way, the cooling camera 1 capable of image shifting is configured.

  The operation of the camera of the present embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of the operating current. The horizontal axis represents time, the left vertical axis represents current, and the right vertical axis represents temperature.

  In FIG. 2, when the user turns on the camera 1, the current Ip is applied to the Peltier element 5 via the Peltier driver 21.

  As the current Ip is applied to the Peltier element 5 and the contact surface with the image sensor 3 is cooled, the image sensor 3 is cooled and the temperature of the image sensor 3 changes from Tr (room temperature) to the set temperature T0 with time. Thereafter, the current Ip of the Peltier element 5 is controlled by the control device 9 via the Peltier driver 21 so as to maintain the temperature of T0.

  Until the temperature Tr reaches the vicinity of the temperature T0, the maximum current Imax is applied to the Peltier element 5 to rapidly cool the imaging element 3, and after reaching the temperature T0, a small current I is applied to keep the temperature constant. Control to hold. At this time, the control device 9 controls the current I applied from the Peltier driver 21 based on the information from the temperature sensor 19 so as to keep the temperature of the image sensor 3 constant.

  In addition, a current Im for maintaining the rotational position of the motor 27 is constantly applied to the motor 27. Thereby, the position (or inclination) of the parallel flat glass 23 of the image shift device 7 is fixed and maintained.

  Conventionally, when the current Id is applied to the motor 27 in order to rotate the cam ring 25 while the applied current I is applied to the Peltier element 5, there is a problem that the total current I + Id exceeds the allowable current of the power source. In order to increase the allowable current as a countermeasure, if the power source is composed of a large power source, wiring material, and a large connector, the power source becomes large and expensive.

  In the camera 1 of the present embodiment, the motor drive current Id is applied during the drive time td of the motor 27, and the motor driver 29 and the Peltier driver are controlled by the control device 9 so as to reduce the current I of the Peltier element 5 to the minimum current Imin. By controlling each of 21 (also referred to as exclusive control), the current consumption of the camera 1 can be suppressed to an allowable value or less.

  For example, the power supply (current) capacity that can be supplied to the camera 1 and the allowable current value for safety such as a cable (not shown) and a connector (not shown) that is safe are 0.5 A, and the maximum driving current of the Peltier element 5 on the load side When I is 0.3 A and the maximum current Id of the motor 27 is 0.3 A, when the driving of the Peltier element 5 and the driving of the motor 27 are simultaneously performed at the maximum, the total current value is 0.6 A and the allowable current value is 0. It will exceed 5A.

  In the present embodiment, the driving current I of the Peltier element 5 is suppressed to the minimum Imin = 0.1 A at the time td when the motor 27 is driven, and even if it is combined with the driving current Id (= 0.3 A) of the motor 27, I + Id = The control device 9 can exclusively control the drive current I of the Peltier element 5 and the drive current Id of the motor 27 so that the allowable current is 0.5 A or less at 0.4 A.

  In addition, after the power is turned on, the motor 27 is driven and the parallel plate glass 23 of the image shift device 7 is moved to the initial position (on the optical axis) until the temperature of the image sensor 3 reaches the predetermined temperature T0 from the room temperature Tr. It is desirable to perform a reset operation R that is set to a vertical position.

  Also during the reset operation R, as described above, the motor drive current Id is applied during the drive time td of the motor 27, and the motor 9 is controlled by the controller 9 so that the current Imax of the Peltier element 5 is reduced to the minimum current Imin. By controlling the driver 29 and the Peltier driver 21 (also referred to as exclusive control), the current consumption of the camera 1 can be suppressed to an allowable value or less. At this time, since the heat capacities of the image pickup device 3, the Peltier device 5, and the heat sink 17 are large, the time constant of the temperature change of the image pickup device 3 is large and the driving time td of the motor 27 is short. And the influence on the time to reach the target cooling temperature T0 is almost negligible. Note that the reset operation may be performed during a period in which the temperature is constant at T0. Even during this period, the temperature change of the image sensor 3 is almost negligible, and it can be said that there is almost no influence on the photographing.

  As described above, according to the present embodiment, the pixel consumption operation by driving the motor 27 of the image shift device 7 and the cooling operation by the Peltier element 5 are exclusively controlled to optimize the maximum current consumption to the minimum necessary. It becomes possible to do. Accordingly, the size and cost of the power source, connector, harness, and camera head can be minimized.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

It is a block diagram of the configuration of a cooling camera capable of image shifting according to the present embodiment. It is a figure which shows an example of an operating current. The horizontal axis represents time, the left vertical axis represents current, and the right vertical axis represents temperature.

Explanation of symbols

1 Image-shiftable cooling camera (camera)
DESCRIPTION OF SYMBOLS 3 Image pick-up element 5 Peltier element 7 Image shift device 9 Control apparatus 11 Image pick-up element driver 13 Image processing circuit 15 Monitor 17 Heat sink 19 Temperature sensor 21 Peltier driver 23 Parallel plate glass 25 Cam ring 27 Motor 29 Motor driver

Claims (6)

An image sensor;
A cooling element for cooling the imaging element;
Image shifting means for shifting a light beam incident on the image sensor in a plane of the image sensor;
Drive means for driving the image shift means,
An image-shiftable cooling camera comprising control means for controlling a current supplied to the driving means and a current supplied to the cooling element within an allowable current.   2. The image shiftable according to claim 1, wherein the control unit reduces a current to the cooling element when supplying a predetermined current to the driving unit to drive the image shifting unit. Cooling camera. Detecting means for detecting the temperature of the image sensor;
The control means, when the signal from the detection means is below a predetermined temperature,
3. The image-shiftable cooling camera according to claim 1, wherein the driving unit is driven to reset the image shift unit.   4. The image-shiftable cooling camera according to claim 1, wherein the driving unit is a pulse motor. 5. The image shift means has parallel flat glass,
5. The image-shiftable cooling camera according to claim 1, wherein the driving unit tilts the parallel flat glass with respect to an optical axis of a light beam incident on the imaging element. 6. The image shift means has a cam ring in which a cam for inclining the parallel flat glass is formed,
6. The image-shiftable cooling camera according to claim 1, wherein the driving unit drives the cam ring.

Images