JP2013182137A - Optical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid detection error due to external light by an optical sensor for detecting a position of an optical member and incidence of unnecessary light on an imaging element.SOLUTION: An optical instrument includes: a movable optical member 4, 34; an optical member 7 in which a light emitting unit 7a and a light receiving unit 7b are included, and a value of an output signal from the light receiving unit is changed by moving a light shielding unit 4d movable along with the optical member with respect to the light emitting unit and the light receiving unit; position detection means 61 that detects a position of the optical member in accordance with change of the value of the output signal; and brightness detection means 59 that detects brightness of environment. The position detection means changes light emission intensity of the light emitting unit in accordance with the brightness detected by the brightness detection means.

Description

  The present invention relates to an optical apparatus that detects the position of a movable optical member such as a lens using an optical sensor such as a photo interrupter.

  In an optical device such as a camera or an interchangeable lens that moves a lens or other optical member for focusing or zooming, an optical sensor such as a photo interrupter is often used to detect the position of the optical member. For example, a light-shielding part that can move with an optical member enters between a light-emitting part and a light-receiving part of a photosensor arranged at a predetermined position, so that the light-receiving part that has received light from the light-emitting part until then can receive light. Does not reach, and the output signal value from the light receiving section changes. By monitoring this change in the output signal value, it is possible to detect that the optical member is located at a predetermined position (that is, the optical member is reset to the origin). The position of the optical member relative to the origin can be detected by measuring (counting) the amount of movement of the optical member after the origin reset.

  The origin reset as described above is generally performed when the optical device is turned on. However, when the optical device is continuously used for a long time, the optical member is displaced due to vibration or impact during the operation. In order to correct, it may be performed with a fixed period. In addition, the output signal value from the light receiving unit indicates that the light has reached the light receiving unit while the optical member is held at the origin (the light from the light emitting unit is blocked by the light blocking unit). If it increases, it can be determined that an abnormality that the optical member is displaced due to some impact has occurred.

  However, even if the light from the light-emitting part is blocked by the light-shielding part, the light that enters the inside from the outside of the optical device (external light) reaches the light-receiving part, so that the origin reset may not be performed correctly or erroneously. An abnormal judgment may be made. Further, when the light emission intensity of the light emitting part is increased to make it less susceptible to such external light, there is a possibility that light from the light emitting part may enter the image sensor as unnecessary light such as ghost light.

  Patent Document 1 has an isolation wall that forms a storage space for an optical sensor that is isolated from a moving space of a lens frame, and the isolation wall inserts and removes a light shielding portion provided in the lens frame with respect to the storage space. An optical instrument having an insertion / removal opening is disclosed. The isolation wall is provided in order to prevent external light from reaching the optical sensor and unnecessary light from entering the image sensor.

JP 2007-33958 A

However, in the optical device disclosed in Patent Document 1, although the isolation wall is formed between the movement space of the lens frame and the storage space of the optical sensor, the lens frame is largely extended with respect to the isolation wall. Then both spaces are connected spaces. For this reason, the possibility that external light or unnecessary light is reflected a plurality of times inside the optical device and reaches the optical sensor or enters the image sensor cannot be excluded. In addition to the need for a space for providing an isolation wall inside the optical device, the optical device is also limited in configuration, which may hinder miniaturization of the optical device.

  The present invention provides a small optical device that can avoid erroneous detection due to external light of an optical sensor for detecting the position of an optical member and incidence of unnecessary light on an image sensor.

  An optical apparatus according to an aspect of the present invention includes a movable optical member, a light emitting unit, and a light receiving unit, and the light shielding unit that can move together with the optical member moves relative to the light emitting unit and the light receiving unit. An optical sensor that changes the value of the output signal, a position detection unit that detects the position of the optical member in accordance with the change in the value of the output signal, and a brightness detection unit that detects the brightness of the outside world. The position detecting unit changes the light emission intensity of the light emitting unit according to the brightness detected by the brightness detecting unit.

According to the present invention, by changing the light emission intensity of the light emitting portion of the optical sensor according to the brightness of the outside world, the external light can be obtained without increasing the size of the optical device by providing an isolation wall inside the optical device. It is possible to avoid erroneous detection of the optical sensor due to, and incidence of unnecessary light from the optical sensor to the image sensor. For example, when the external environment is bright and external light easily reaches the light receiving portion of the photosensor, erroneous detection of the photosensor can be avoided by increasing the emission intensity. In addition, when the external environment is dark and unnecessary light from the light emitting portion of the optical sensor is likely to enter the image sensor, this can be avoided by reducing the light emission intensity.

1 is an exploded perspective view of a video camera that is Embodiment 1 of the present invention. 1 is a cross-sectional view of a video camera according to Embodiment 1. FIG. FIG. 3 is a perspective view of a focus driving unit in the video camera according to the first embodiment. The figure which shows the origin reset operation | movement in the camera of the video camera of the video of Example 1. FIG. FIG. 2 is a block diagram illustrating an electrical configuration of the video camera according to the first embodiment. 3 is a flowchart showing the operation of the video camera according to the first embodiment. The figure which shows the sensor setting in Example 1 and Example 2 of this invention. 9 is a flowchart showing the operation of a video camera that is Embodiment 2 of the present invention. 9 is a flowchart showing the operation of a video camera that is Embodiment 3 of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the configuration of a lens barrel of a video camera as an optical apparatus that is Embodiment 1 of the present invention. An imaging optical system configured by first to fourth lens groups and a diaphragm unit, which will be described later, is housed in the lens barrel. FIG. 2 shows a state of the lens mirror or the like at the wide angle end-infinity. In these drawings, the first group lens barrel 1 holds the first lens group 31 by a lens holding portion provided at the front end portion (the portion closest to the subject). A rear barrel 6 is coupled to the rear end portion (the portion closest to the imaging surface) of the first group barrel 1. Further, the image sensor holding frame 5 is coupled to the rear end portion of the rear barrel 6. The first group barrel 1, the rear barrel 6, and the image sensor holding frame 5 constitute a barrel body that forms a barrel space that accommodates components described below.

  The second group barrel 2 holds a second lens group 32 as a zoom lens. The second lens group 32 and the second group barrel 2 constitute an optical member that can move in the optical axis direction. The zoom slack 10 and the zoom rack spring 16 are attached to the rack attachment portion 2 a of the second group barrel 2. Further, the sleeve portion 2b and the U-groove portion 2c of the second group barrel 2 are respectively engaged with the first guide bar 17 and the second guide bar 27 so as to be movable in the optical axis direction. Is guided in the optical axis direction. Both ends of the first guide bar 17 are held by the first group barrel 1 and the rear barrel 6, and both ends of the second guide bar 27 are held by the first group barrel 1 and a third group barrel 3 described later. The

  The zoom slack 10 meshes with the lead screw 9a of the zoom motor unit 9 without play by the biasing force of the zoom rack spring 16. Thus, when the lead screw 9a rotates, the second group barrel 2 moves in the optical axis direction, and zooming is performed. The zoom motor unit 9 is constituted by a stepping motor and is attached to the rear barrel 6.

  The third group barrel 3 holds the third lens group 33 and is fixedly held by the rear barrel 6 between the second group barrel 2 and a fourth group barrel 4 described later.

  The aperture unit 8 is fixed to the third group barrel 3. The diaphragm unit 8 changes the diaphragm aperture diameter by moving a plurality of diaphragm blades, and adjusts the amount of light reaching an image sensor, which will be described later.

  The fourth group barrel 4 holds a fourth lens group 34 as a focus lens. The fourth lens group 34 and the fourth group barrel 4 constitute an optical member that can move in the optical axis direction. A focus slack 13 and a focus rack spring 15 are attached to the rack attachment portion 4 a of the fourth group barrel 4. Further, the sleeve portion 4b and the U-groove portion 4c of the fourth group barrel 4 are respectively engaged with the third guide bar 28 and the fourth guide bar 29 so as to be movable in the optical axis direction. Is guided in the optical axis direction. Both ends of the third guide bar 28 are held by the first group barrel 1 and the rear barrel 6, and both ends of the fourth guide bar 29 are held by the third group barrel 3 and the rear barrel 6.

  The focus slack 13 meshes with the lead screw 12a of the focus motor unit 12 without play by the biasing force of the focus rack spring 15. Thus, when the lead screw 12a rotates, the fourth group barrel 4 moves in the optical axis direction, and focusing is performed. The focus motor unit 12 is configured by a stepping motor and is attached to the rear barrel 6.

  A zoom reset sensor 11 and a focus reset sensor 7 constituted by a photo interrupter as an optical sensor are attached to the rear barrel 6. The zoom reset sensor 11 is provided to detect that the second group barrel 2 is located at the origin position in the optical axis direction (hereinafter referred to as the zoom origin). The focus reset sensor 7 is provided to detect that the fourth group barrel 4 is located at the origin position in the optical axis direction (hereinafter referred to as the focus origin).

  An image sensor (not shown) constituted by a CCD sensor or a CMOS sensor is attached to the sensor attachment portion 5 f of the image sensor holding frame 5.

  Two openings are formed in the filter frame 18, one opening is covered with an infrared cut filter 23 as an optical filter, and the other opening is covered with a dummy glass 26. The filter frame 18 is guided by a fifth guide bar 19 so as to be movable in a direction orthogonal to the optical axis direction. A filter rack 20 and a filter rack spring 21 are attached to the filter frame 18. An engineering filter other than the infrared cut filter may be provided in the filter frame 18.

  The filter rack 20 meshes with a lead screw (not shown) of the filter motor unit 22 without play by the urging force of the filter rack spring 21. As a result, when the lead screw rotates, the filter frame 18 moves in a direction orthogonal to the optical axis direction, and the infrared cut filter 23 or the dummy glass 26 faces the imaging element in the imaging optical system (that is, imaging). On the optical path). When priority is given to color reproducibility in imaging, an infrared cut filter 23 is arranged on the imaging optical path, and when priority is given to brightness, a dummy glass 26 is arranged on the imaging optical axis. The filter motor unit 22 includes a stepping motor and is attached to the image sensor holding frame 5.

  A filter position sensor 25 constituted by a photo interrupter as an optical sensor is attached to the image sensor holding frame 5. The filter position sensor 25 is provided to detect that the dummy glass 26 is located at a position facing the imaging device (origin position: hereinafter referred to as a filter retracting position) in the direction orthogonal to the optical axis direction. It has been.

  FIG. 3 shows a configuration of the focus driving unit including the above-described fourth group barrel 4, the focus motor unit 12, and the focus reset sensor 7. In this figure, a light blocking portion 4d is formed in the fourth group barrel 4. The focus reset sensor 7 includes a light emitting unit 7a and a light receiving unit 7b arranged so as to face each other.

  When the fourth group lens barrel 4 having the light shielding portion 4d moves toward the focus origin with respect to the focus reset sensor 7 fixed to the rear lens barrel 6, the light shielding portion 4d enters between the light emitting portion 7a and the light receiving portion 7b. The light emitted from the light emitting unit 7a and traveling toward the light receiving unit 7b is blocked. As a result, a low level signal is output from the light receiving unit 7b that has previously received light from the light emitting unit 7a and has output a high level signal. The control circuit to be described later confirms that the fourth group lens barrel 4 is positioned at the focus origin in response to a change in the value of the output signal from the light receiving unit 7b (here, a change from the High level to the Low level). To detect.

  Here, the light receiving unit 7b outputs a signal having a value (voltage) corresponding to the intensity (or light amount) of the light incident on the light receiving unit 7b. That is, a higher value signal is output as the light receiving intensity of the light receiving unit 7b is higher. The control circuit provides a predetermined threshold value for determining the High level and the Low level described above. When the output signal value from the light receiving unit 7b is higher than the threshold value, the control circuit determines that the output signal value is lower than the threshold value. Is determined to be Low level.

  The control circuit uses the output signal from the focus reset sensor 7 to count the number of pulses of the drive pulse signal supplied to the focus motor unit 12 when it is detected that the fourth group barrel 4 is located at the focus origin. Thus, the amount of movement of the fourth group barrel 4 from the focus origin, that is, the position of the fourth group barrel 4 can be detected.

  In this embodiment, the case where the light shielding part 4d enters between the light emitting part 7a and the light receiving part 7b when the fourth group barrel 4 is located at the focus origin will be described. However, the light shielding part 4d is connected to the light emitting part 7a. You may comprise so that it may escape from between the light-receiving parts 7b. In this case, it is possible to detect that the fourth group barrel 4 is located at the focus origin in response to the value of the output signal from the light emitting unit 7a changing from the Low level to the High level. The same applies to the zoom drive unit and filter drive unit described below.

  Further, the zoom driving unit including the above-described second group barrel 2, zoom motor unit 9, and zoom reset sensor 11 is not shown in detail, but the light shielding portion formed on the second group barrel 2 moved to the zoom origin is zoomed. It enters between the light emitting part and the light receiving part of the reset sensor 11. Similar to the fourth group barrel 4, the control circuit detects that the second group barrel 2 is positioned at the zoom origin in response to the value of the output signal from the light receiving unit changing from the High level to the Low level. Then, the control circuit counts the number of pulses of the drive pulse signal supplied to the zoom motor unit 9 when it is detected that the second group barrel 2 is located at the zoom origin using the output signal from the zoom reset sensor 11. To do. Thereby, the amount of movement of the second group barrel 2 from the zoom origin, that is, the position of the second group barrel 2 can be detected.

  The movement of the fourth group barrel 4 and the second group barrel 2 to the focus origin and zoom origin (hereinafter referred to as origin reset) is performed when the video camera is turned on, and thereafter is performed at a constant cycle. In addition, by monitoring changes in the output signals from these sensors 7 and 11, the fourth and second group barrels 4 and 2 are displaced from the focus and zoom origins due to vibrations and shocks applied to the video camera. Can also detect that an abnormality has occurred.

  Also in the filter driving unit including the filter frame 18, the filter motor unit 22, and the filter position sensor 25, although not shown in detail, the light shielding unit formed on the filter frame 18 moved to the filter retracted position is the light emitting unit of the filter position sensor 25. And the light receiving part. In the control circuit, the filter frame 18 is positioned at the filter retracted position in accordance with the change in the value of the output signal from the light receiving unit from the high level to the low level, as in the case of the fourth group and the second group barrels 4 and 2. Is detected. The control circuit inputs a drive pulse signal having a predetermined number of pulses to the filter motor unit 22 from the state in which it is detected that the filter frame 18 is located at the filter retracted position. Thereby, the filter frame 18 can be moved to a position where the infrared cut filter 23 faces the image sensor (hereinafter referred to as a filter insertion position).

  The movement of the filter frame 18 to the filter retracted position (hereinafter referred to as filter reset) is performed when the power of the video camera is turned on, and thereafter is performed at a constant cycle. Further, by monitoring the change in the output signal from the filter position sensor 25, the filter frame 18 has been displaced from the filter retracted position or the filter insertion position due to vibration or impact applied to the video camera, that is, an abnormality has occurred. Can also be detected.

  FIG. 5 shows the electrical configuration of the video camera of this embodiment. In FIG. 5, the components shown in FIG. 1 are denoted by the same reference numerals as those in FIG. The control circuit 61 described above is composed of peripheral components such as a CPU and a memory, and controls the zoom motor unit 9 via the zoom motor driver 54 to move the second group barrel 2 in the optical axis direction. The control circuit 61 controls the focus motor unit 12 via the focus motor driver 58 and moves the fourth group barrel 4 in the optical axis direction.

  Further, the control circuit 61 as position detecting means controls the voltage input to the light emitting unit of the zoom reset sensor 11 via the zoom reset sensor voltage input unit 67. The light emitting section emits light with higher light emission intensity as the input voltage is higher. The control circuit 61 detects the output voltage from the light receiving unit of the zoom reset sensor 11 through the zoom reset sensor voltage output unit 67. Then, the position of the second group barrel 2 (the second group barrel 2 is located at the zoom origin) is detected (determined) in response to the change of the output voltage from the High level to the Low level.

  The control circuit 61 controls the voltage input to the light emitting unit 7 a of the focus reset sensor 7 via the focus reset sensor voltage input unit 69. The light emitting unit 7a emits light with higher light emission intensity as the input voltage is higher. The control circuit 61 detects the output voltage from the light receiving unit 7 b of the focus reset sensor 7 through the focus reset sensor voltage output unit 70. Then, the position of the fourth group barrel 4 (that the fourth group barrel 4 is located at the focus origin) is detected (determined) in response to the change in the output voltage from the High level to the Low level.

  The control circuit 61 controls the voltage input to the light emitting unit of the filter position sensor 25 via the filter position sensor voltage input unit 71. The light emitting section emits light with higher light emission intensity as the input voltage is higher. The control circuit 61 detects the output voltage from the light receiving unit of the filter position sensor 25 through the filter position sensor voltage output unit 72. Then, the position of the filter frame 18 (the filter frame 18 is located at the filter retracted position) is detected (determined) in response to the change of the output voltage from the high level to the low level.

  The image sensor 59 photoelectrically converts a subject image (optical image) formed on the imaging surface and outputs an analog image signal. The image processing circuit 60 converts the analog imaging signal into a digital signal, performs various signal processing (color interpolation processing, γ correction processing, white balance processing, shading correction processing, etc.) on the digital signal, and converts the video signal into Generate.

  The control circuit 61 detects the brightness of the subject, that is, the outside world, using a luminance signal indicating brightness among the video signals generated by the image processing circuit 60. Then, depending on the brightness detection result, input voltages supplied to the sensors 11, 7, and 25 through the zoom reset sensor voltage input unit 67, the focus reset sensor voltage input unit 69, and the filter position sensor voltage input unit 71, respectively. Control. In this embodiment, the image sensor 59 is used as a brightness detection unit.

  FIG. 4 shows the positions of movable optical members corresponding to the second group barrel 2, the fourth group barrel 4 and the filter frame 18, and the photointerrupters constituting the zoom reset sensor 11, the focus reset sensor 7 and the filter position sensor 25. The relationship with the output signal (voltage) from a light-receiving part is shown.

  When the light shielding portion of the movable optical member does not enter between the light emitting portion and the light receiving portion of the photo interrupter (hereinafter referred to as a non-light shielding state), the output voltage from the photo interrupter is the highest value. On the other hand, in a state where the light shielding portion is completely inserted between the light emitting portion and the light receiving portion (hereinafter referred to as the light shielding state), the output voltage from the photo interrupter is the lowest value (almost 0V). Here, the state where the light shielding portion is incompletely inserted between the light emitting portion and the light receiving portion is referred to as a boundary state between the light shielding state and the non-light shielding state. In this boundary state, the output voltage from the photo interrupter gradually decreases from the maximum value to the minimum value as the light-shielding state approaches from the non-light-shielding state, that is, as the light-receiving intensity at the light-receiving portion decreases due to the movement of the light-shielding portion. To do.

  In this embodiment, any output voltage in the change range of the output voltage from the photo interrupter in the boundary state (a range smaller than the maximum value and larger than the minimum value) is set as the above-described predetermined threshold for High / Low determination. Set as level. Then, the position of the movable barrel where the output voltage changes from the High level higher than the threshold level to the Low level lower (or lower) than the threshold level is defined as the origin position (zoom origin, focus origin, and filter retract position). Detect as. In other words, the origin position is detected in response to a change in the output voltage from the photo interrupter so as to pass the high / low determination threshold level.

  However, even if the photo interrupter is in a boundary state or a light shielding state, external light that has entered the inside of the lens barrel space from the outside of the lens barrel portion (for example, through the first lens group 31) reaches the light interrupting portion of the photo interrupter. there's a possibility that. In this case, the output signal from the light receiving unit that has received the external light increases from the low level to the high level, and there is a possibility that correct origin reset may not be performed or erroneous abnormality determination may be performed. That is, there is a possibility that erroneous detection by the photo interrupter (sensor) may occur.

  In order to eliminate the influence of such external light, if the emission intensity of the light emitting part is increased and the high / low determination threshold level is set high, the light from the light emitting part is reflected directly or inside the lens barrel. Therefore, there is a possibility that the image sensor may be incident as unnecessary light such as ghost light.

  In the present embodiment, these problems are solved by controlling the input voltage supplied to the light emitting portion of each photo interrupter, that is, the light emission intensity of the light emitting portion as follows.

  The flowchart of FIG. 6 shows the control of each photo interrupter in the present embodiment. Here, the zoom reset sensor 11 and the focus reset sensor 7 will be described as photo interrupters to be controlled. However, the filter position sensor 25 can be similarly controlled. This control is executed by the control circuit 61 according to the computer program. These are the same in other embodiments described later.

  When the power of the video camera is turned on, the control circuit 61 sets the input voltage for the zoom reset sensor 11 and the focus reset sensor 7 to the first input voltage as an initial set value in step S101. Also, the high / low determination threshold level for the output voltage from each sensor is set to the first threshold level corresponding to the first input voltage. In the following description, the setting of the first input voltage and the first threshold level is also referred to as a first sensor setting.

  Next, in step S102, the control circuit 61 drives the zoom motor unit 9 and the focus motor unit 12 to reset the origin of the second group barrel 2 and the fourth group barrel 4.

  Next, in step S103, the control circuit 61 drives the zoom motor unit 9 to move the second group barrel 2 from the zoom origin to a predetermined zoom position such as the wide end. The control circuit 61 drives the focus motor unit 12 to move the fourth group barrel 4 to a focus position corresponding to a predetermined zoom position.

  Next, in step S <b> 104, the control circuit 61 captures a video signal (image) generated by processing the image signal output from the image sensor 59 by the image processing unit 60.

  In step S105, the control circuit 61 determines the amount of light from the subject (external environment) received by the image sensor 59 from the luminance signal included in the video signal (that is, the brightness of the external environment, hereinafter referred to as external light amount). Then, it is determined whether or not the external light quantity is a predetermined light quantity (threshold value) or less. If the external light amount is less than or equal to the predetermined light amount (that is, the external environment is dark), the process proceeds to step S106. If the external light amount is not less than the predetermined light amount (that is, the external environment is bright), the process proceeds to step S107.

  In step S106, the control circuit 61 changes the input voltages for the zoom reset sensor 11 and the focus reset sensor 7 to a second input voltage lower than the first input voltage. Further, the high / low determination threshold level for the output voltages from the sensors 11 and 7 is changed to a second threshold level lower than the first threshold level corresponding to the second input voltage. In the following description, the setting of the second input voltage and the second threshold level is also referred to as a second sensor setting. Then, the process returns to steps S104 and S105, and the determination of the external light quantity is repeated.

  The difference between the first input voltage and the second input voltage, and the difference between the first threshold level and the second threshold level may be obtained in advance by design simulation, or the actual measurement result for each individual video camera. You may decide accordingly.

  On the other hand, in step S107, the control circuit 61 maintains the first sensor setting if the first sensor setting has been made so far, and the first circuit setting if the second sensor setting has been made until then. Switch to sensor settings. Then, the process returns to steps S104 and S105, and the determination of the external light quantity is repeated.

  The first sensor setting and the second sensor setting will be described in more detail with reference to FIG. FIG. 7A shows the relationship between the first input voltage and the first threshold level in the first sensor setting. FIG. 7B shows the relationship between the second input voltage and the second threshold level in the second sensor setting. Since the second input voltage is lower than the first input voltage, the output voltage from the light receiving unit of each sensor also decreases accordingly. For this reason, the high / low determination threshold level is corrected to be lowered to the second threshold level as the input voltage is lowered. Thus, the lower the input voltage, the lower the High / Low determination threshold level. Thereby, even if the input voltage to each sensor is changed, the origin position of each lens barrel detected by each sensor can be made the same. Here, “same” includes not only the case where they are completely the same, but also the case where they are within the allowable error range.

  FIG. 7C and FIG. 7D show a state in which external light is incident on the sensor. When external light enters the light receiving part of the sensor, the output voltage from the light receiving part rises even in a light-shielded state. The brighter the external world, the greater the amount of external light incident on the sensor, and the greater the amount of increase in output voltage due to external light. In this situation, as shown in FIG. 7D, if the threshold level for high / low determination is set low together with the input voltage, the margin of the threshold level with respect to the increased output voltage is small, and erroneous detection by the sensor. The possibility of is increased.

  However, in this embodiment, when the outside world is bright, the first sensor setting is made as shown in FIG. 7C, and both the input voltage to each sensor and the high / low determination threshold level are set high. . That is, the threshold level margin for the output voltage that may increase in the light-shielding state is increased. For this reason, the possibility of erroneous detection by each sensor can be reduced.

  When the outside is dark, the second sensor setting is made as shown in FIG. 7B, and the light emission intensity of the light emitting part is lowered, so that the light from the light emitting part is reflected directly or inside the lens barrel. The possibility of entering the image sensor 59 as unnecessary light such as ghost light can be avoided.

  FIG. 7 (e) and FIG. 7 (f) show a second embodiment of the present invention. In Example 1, the high / low determination threshold level was corrected in accordance with the input voltage (emission intensity of the light emitting unit) to each sensor. In contrast, in this embodiment, the high / low determination threshold level is constant regardless of the input voltage to each sensor. Instead, the origin position of each movable optical member detected at this threshold level is corrected.

  Specifically, FIG. 7E shows a first sensor setting in which the input voltage to the zoom reset sensor 11 and the focus reset sensor 7 is the first input voltage. FIG. 7F shows a second sensor setting in which the input voltage to these sensors 11 and 7 is lower than the first input voltage. The high / low determination threshold levels in the first sensor setting and the second sensor setting are equal to each other. For this reason, the difference between the output voltage from the light receiving unit in the light-shielded state and the high / low determination threshold level in the first and second sensor settings is also equal to each other.

  Also in the present embodiment, in a situation where the external environment is bright, the first sensor setting is made, the input voltage to each sensor is set high, and the threshold level margin for the output voltage that may increase in the light-shielded state is large. For this reason, the possibility of erroneous detection by each sensor can be reduced. In a dark environment, the second sensor setting is made to lower the light emission intensity of the light emitting part, so that light from the light emitting part is reflected directly or inside the lens barrel and ghost light or the like is unnecessary for the image sensor 59. The possibility of entering as light can be avoided.

  However, in the first sensor setting, the position 151 where the output voltage of the light receiving unit corresponding to the high / low determination threshold level is obtained is detected as the origin position. On the other hand, in the second sensor setting, since the output voltage of the light receiving unit corresponding to the same threshold level is obtained at a position 152 different from the position 151, this position 152 is detected as the origin position. That is, the position detected as the origin position is different between the first sensor setting and the second sensor setting.

  Therefore, in this embodiment, the input voltage to each sensor is changed according to the brightness of the outside world, and the position of the movable optical member that is finally detected (determined) by the control circuit 61 regardless of the change of the input voltage. Are corrected so that the detection positions corresponding to the threshold levels are equal.

  In the first and second embodiments, the case where the image sensor 59 is used as the brightness detection unit has been described. However, brightness detection units other than the image sensor may be provided. For example, a sensor that detects the brightness of the outside world may be provided on the outer surface of the video camera. Further, as in Example 4 described later, the filter position sensor 25 may be used as brightness detection means.

  The flowchart of FIG. 8 shows control of each photo interrupter in the video camera which is Embodiment 3 of the present invention. The configuration of the video camera of the present embodiment is the same as that described in the first embodiment. For this reason, in this embodiment, the same reference numerals as those in the first embodiment are assigned to the components common to the first embodiment.

  When the power of the video camera is turned on, the control circuit 61 sets the input voltage for the zoom reset sensor 11 and the focus reset sensor 7 to the first input voltage as an initial set value in step S201. Also, the high / low determination threshold level for the output voltage from each sensor is set to the first threshold level corresponding to the first input voltage. The setting of the first input voltage and the first threshold level is also referred to as a first sensor setting as in the first embodiment.

  Next, in step S202, the control circuit 61 drives the zoom motor unit 9 and the focus motor unit 12 to reset the origins of the second group barrel 2 and the fourth group barrel 4.

  Next, in step S203, the control circuit 61 drives the zoom motor unit 9 to move the second group barrel 2 from the zoom origin to a predetermined zoom position such as the wide end. The control circuit 61 drives the focus motor unit 12 to move the fourth group barrel 4 to a focus position corresponding to a predetermined zoom position.

  Next, in step S <b> 204, the control circuit 61 captures a video signal (image) generated by processing the imaging signal output from the imaging element 59 by the image processing unit 60.

  Next, in step S <b> 205, the control circuit 61 determines whether or not the output voltage from the light receiving unit of the filter position sensor 25 obtained through the filter position sensor voltage output unit 72 indicates the filter insertion position of the filter frame 18. To do. That is, it is determined whether or not the infrared cut filter 23 is inserted on the imaging optical path. If it is not inserted, the process proceeds to step S206. If it is inserted, the process proceeds to step S208.

  In step S206, the control circuit 61 determines the external light amount from the luminance signal included in the video signal, and determines whether the external light amount is equal to or less than a predetermined light amount (threshold value). If the external light quantity is less than or equal to the predetermined light quantity (that is, the external environment is dark), the process proceeds to step S207. If the external light quantity is not less than the predetermined light quantity (that is, the external environment is bright), the process proceeds to step S208.

  In step S207, the control circuit 61 changes the input voltages for the zoom reset sensor 11 and the focus reset sensor 7 to a second input voltage lower than the first input voltage. Further, the high / low determination threshold level for the output voltages from these sensors 11 and 7 is changed to a second threshold level lower than the first threshold level corresponding to the second input voltage. The setting of the second input voltage and the second threshold level is also referred to as a second sensor setting as in the first embodiment. Then, steps S204 to S206 are repeated.

  On the other hand, in step S208, the control circuit 61 maintains the first sensor setting if the first sensor setting has been made so far, and the first circuit setting if the second sensor setting has been made so far. Switch to sensor settings. Then, steps S204 to S206 are repeated.

  In this embodiment, on the condition that the infrared cut filter 23 is not inserted in the imaging optical path (the filter frame 18 is in the filter retracted position), the first sensor setting is set to the second sensor when the outside is dark. Change to settings. In general, the light emitted from the light-emitting portion of the photo interrupter contains many light components in the infrared region. For this reason, in a state where the infrared cut filter 23 is inserted in the imaging optical path, most of the light from the light emitting unit is cut by the infrared cut filter 23 and does not reach the imaging element 59, and from the light emitting unit. Is unlikely to be ghost light.

  Therefore, in this embodiment, regardless of the brightness of the external environment, when the infrared cut filter 23 is inserted on the imaging optical path, the input voltage and the High / Low determination threshold level for each sensor are maintained high. That is, advantageous control is performed by preventing erroneous detection due to the incidence of external light on the light receiving portion of each sensor.

  In this embodiment as well, regardless of the input voltage to each sensor, the high / low determination threshold level is made constant, and the origin position of each movable optical member detected at the threshold level is corrected. Also good.

  The flowchart of FIG. 9 shows the control of each photo interrupter in the video camera that is Embodiment 4 of the present invention. The configuration of the video camera of the present embodiment is the same as that described in the first embodiment. For this reason, in this embodiment, the same reference numerals as those in the first embodiment are assigned to the components common to the first embodiment.

  When the power of the video camera is turned on, the control circuit 61 sets the input voltage for the zoom reset sensor 11 and the focus reset sensor 7 to the first input voltage as an initial set value in step S301. Also, the high / low determination threshold level for the output voltage from each sensor is set to the first threshold level corresponding to the first input voltage. The setting of the first input voltage and the first threshold level is also referred to as a first sensor setting as in the first embodiment.

  Next, in step S302, the control circuit 61 drives the zoom motor unit 9 and the focus motor unit 12 to reset the origins of the second group barrel 2 and the fourth group barrel 4.

  Next, in step S303, the control circuit 61 drives the zoom motor unit 9 to move the second group barrel 2 from the zoom origin to a predetermined zoom position such as the wide end. The control circuit 61 drives the focus motor unit 12 to move the fourth group barrel 4 to a focus position corresponding to a predetermined zoom position.

  Next, in step S304, the control circuit 61 determines whether or not the output voltage from the light receiving unit of the filter position sensor 25 obtained through the filter position sensor voltage output unit 72 indicates the filter insertion position of the filter frame 18. To do. That is, it is determined whether or not the infrared cut filter 23 is inserted on the imaging optical path.

  In this embodiment, the infrared cut filter 23 is inserted on the imaging optical path when the outside is bright, and is retracted from the imaging optical path when the outside is dark. That is, the brightness of the outside world can be detected by inserting / retracting the infrared cut filter 23 (that is, whether the filter frame 18 is at the filter insertion position or the filter retract position). If the infrared cut filter 23 is not inserted, the process proceeds to step S305, and if it is inserted, the process proceeds to step S306.

  In step S305, the control circuit 61 changes the input voltage for the zoom reset sensor 11 and the focus reset sensor 7 to a second input voltage lower than the first input voltage. Further, the high / low determination threshold level for the output voltages from these sensors 11 and 7 is changed to a second threshold level lower than the first threshold level corresponding to the second input voltage. The setting of the second input voltage and the second threshold level is also referred to as a second sensor setting as in the first embodiment. Then, step S304 is repeated.

  On the other hand, in step S306, the control circuit 61 maintains the first sensor setting if the first sensor setting has been made so far, and the first circuit setting if the second sensor setting has been made until then. Switch to sensor settings. Then, step S304 is repeated.

  In the present embodiment, as described above, the brightness of the outside world is detected by insertion / retraction of the infrared cut filter 23, and the first sensor setting and the second sensor setting are switched according to the detection result. Also in this embodiment, when the outside world is bright (the infrared cut filter 23 is inserted), the first sensor setting is made, and the possibility of erroneous detection by each sensor can be reduced. Further, when the outside is dark (the infrared cut filter 23 is not inserted), the second sensor setting is performed, and light from the light emitting portion of each sensor is reflected directly or inside the lens barrel, and the image pickup device 59. Therefore, it is possible to avoid the possibility of being incident as unnecessary light such as ghost light.

  In this embodiment as well, regardless of the input voltage to each sensor, the high / low determination threshold level is made constant, and the origin position of each movable optical member detected at the threshold level is corrected. Also good.

  In each of the above-described embodiments, the case where the input voltage to the optical sensor is changed, the high / low determination threshold level is changed, and the detection position of the movable optical member is corrected has been described. However, in order to prevent erroneous detection by the optical sensor and generation of unnecessary light from the optical sensor, it is not always necessary to change the high / low determination threshold level or to correct the detection position of the movable optical member. It is only necessary to change the input voltage (light emission intensity of the light emitting unit).

  In each of the above-described embodiments, the case where the sensor setting is changed in two ways has been described. However, the sensor setting may be changed in three or more ways so as to be able to deal with the brightness of the outside world more precisely.

  Furthermore, in each embodiment, it has been described that the sensor for changing the sensor setting may be a zoom reset sensor and a focus reset sensor, and further the sensor setting of the filter position sensor may be changed. Only the setting may be changed.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

2 2nd lens barrel 4 4th lens barrel 7 Focus reset sensor 11 Zoom reset sensor 59 Image sensor 61 Control circuit

Claims (6)

A movable optical member;
A light sensor having a light-emitting part and a light-receiving part, and a light-shielding part movable along with the optical member moves relative to the light-emitting part and the light-receiving part, and the value of an output signal from the light-receiving part changes,
Position detecting means for detecting the position of the optical member in accordance with a change in the value of the output signal;
Brightness detection means for detecting the brightness of the outside world,
The optical apparatus according to claim 1, wherein the position detection unit changes a light emission intensity of the light emitting unit according to the brightness detected by the brightness detection unit. The position detection means detects the position of the optical member in response to the value of the output signal from the light receiving unit changing so as to pass a predetermined threshold,
The optical apparatus according to claim 1, wherein the position detection unit changes the light emission intensity according to the brightness detected by the brightness detection unit and changes the threshold value. The position detection means detects the position of the optical member in response to the value of the output signal from the light receiving unit changing so as to pass a predetermined threshold,
The position detection means changes the emission intensity according to the brightness detected by the brightness detection means without changing the threshold, and corrects the detected position of the optical member. The optical apparatus according to claim 1. An image sensor that photoelectrically converts an optical image formed by an imaging optical system including the optical member;
4. The optical apparatus according to claim 1, wherein the brightness detection unit detects the brightness of the outside world using a signal output from the imaging device. 5. An optical filter is inserted into and retracted from the imaging optical system including the optical member,
4. The optical apparatus according to claim 1, wherein the brightness detection unit detects the brightness by inserting and retracting the optical filter. 5. The optical filter is inserted and retracted with respect to the imaging optical system including the optical member,
The position detecting means changes the light emission intensity of the light emitting unit according to the brightness detected by the brightness detecting means only when the optical filter is inserted in the imaging optical system. The optical apparatus according to any one of claims 1 to 3.