JP2007171505A - Lens hood and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens hood for preventing the generation of shading during the execution of automatic focusing. <P>SOLUTION: A digital camera 2 comprises a lens unit 4 and a camera body 3. A lens hood 17 is freely detachably fitted to a lens barrel 4. The lens hood 17 is provided with a range finding sensor 90 for photoelectrically converting object light into distance information and an output terminal for transmitting the distance information from the range finding sensor 90 to the external. A connection terminal is formed on the front end of the lens barrel 4, and when the lens hood 17 is fitted to the lens barrel 4 through a Bayonet mechanism, the output terminal is connected to the connection terminal. The lens hood 17 is provided with a dimming sensor 92, a flash device 94, etc. in addition to the range finding sensor 90. The luminance of an object is detected by the dimming sensor 92 and the light emitting quantity of the flash device 94 is controlled in accordance with the luminance of the object. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens hood attached to a lens barrel and a camera to which the lens hood is attached.

  When shooting a subject with a camera, if light from a light source such as the sun or a fluorescent lamp is incident on the shooting lens held by the lens barrel from other than the normal angle of view, ghosts and flares will occur in the shot image. Cause it. In order to shield harmful light incident from other than such a normal angle of view, a lens hood for shielding harmful light is detachably attached to the tip of the lens barrel. As a mechanism for detachably attaching the lens hood to the tip of the lens barrel, for example, a bayonet mechanism is frequently used, and this allows the lens hood to be easily attached to the lens barrel while reducing errors.

  On the other hand, in recent years, many cameras have an autofocus function. As is well known, there are an active method and a passive method for autofocus. The passive method is a phase difference method for obtaining a defocus amount from distance information from a distance measuring sensor provided in a camera, and a subject acquired by an image sensor. There is a contrast method that focuses on the image contrast. In general, the phase difference type autofocus has a short time required for focusing, and the contrast type autofocus has high focusing accuracy.

  By the way, when the user grips the camera and the autofocus sensor provided on the camera is covered with the user's hand, the distance information is not acquired and the defocus amount cannot be calculated. There were times when it failed to match.

  The present invention has been made in view of the above circumstances, and is inspired by a lens hood that is rarely gripped by a user, and an object thereof is to prevent scuffing when performing autofocus.

  In order to achieve the above object, in the lens hood of the present invention, in the lens hood that is detachably attached to the tip of the lens barrel holding the lens, a pair of subject light is received by the light receiving elements, respectively, and distance information is obtained. A distance measuring sensor to be acquired and transmission means for transmitting distance information acquired by the distance measuring sensor are provided.

  The distance measuring sensor receives reflected light from the subject to acquire distance information, and is provided with a flash device that irradiates the subject with light.

  In addition, a light control sensor for adjusting the light emission level of the flash device is provided.

  Further, an ultraviolet sensor for measuring the intensity of ultraviolet rays is provided.

  Further, the camera of the present invention is characterized in that the lens hood is detachably attached, and an adjustment means for adjusting the direction of the distance measuring sensor in response to distance information from the lens hood is provided.

  According to the lens hood of the present invention, in the lens hood that is detachably attached to the tip of the lens barrel that holds the lens, a distance measuring sensor that receives a pair of subject light by the light receiving element and acquires distance information; A transmission means for transmitting the distance information acquired by the distance measuring sensor, and the distance information acquired by the distance measuring sensor and the distance measuring sensor on the lens hood attached to the tip of the lens barrel of the camera. Since the transmission means for transmitting to the outside is provided, it is possible to prevent injuries from occurring when the user holds the camera.

  Further, the distance measuring sensor receives the reflected light from the subject to acquire distance information, and by providing a flash device that irradiates the subject with light, the subject can be reliably irradiated with light.

  Further, by providing a light control sensor for adjusting the light emission level of the flash device, the light emission level of the flash device can be adjusted to obtain good subject light.

  In addition, by providing an ultraviolet sensor for measuring the intensity of ultraviolet rays, it is possible to accurately distinguish between indoors and outdoors based on measurement signals from the ultraviolet sensors.

  In the camera of the present invention, the lens hood is detachably attached, and the distance sensor is provided with adjusting means for receiving the distance information from the lens hood, so that the distance sensor can be easily oriented. It is possible to provide a camera that adjusts and performs good autofocus.

  As shown in FIG. 1, a photographing lens 8 is provided on the front surface of a digital camera 2 that is an electronic camera of the present invention, and a shutter that is pressed to start recording of image data is provided above the digital camera 2. A button 5, a mode dial 6 that is rotated to change the mode of the digital camera 2 such as still image shooting and moving image shooting, and a light emitting unit 7 that emits strobe light or AF auxiliary light in front are provided. . Although not shown, a side of the digital camera 2 is provided with a USB port, an IEEE 1394 port, a video terminal, and the like.

  As shown in FIG. 2, the digital camera 2 includes a camera body 3 and a lens barrel 4. The outer shape of the lens barrel 4 is formed in a substantially cylindrical shape, the photographing lens 8 is exposed from one end thereof, and a CCD image sensor 20 or the like is incorporated therein. At the other end of the lens barrel 4, a lens barrel side mount portion 15 for combining with the camera body 3 is formed. A support portion (not shown) is formed on the abdomen of the lens barrel 4 so that the lens barrel 4 can be placed on, for example, a flat place when the lens barrel 4 is separated from the camera body 3. Although not shown, the lens barrel 4 is provided with an antenna for wireless communication with the camera body 3.

  Inside the exterior cover that covers the lens barrel 4, a lens holding frame that holds the photographing lens 8, a lens barrel that holds the lens holding frame so as to be movable in the optical axis direction, an optical low-pass filter (not shown), and will be described later. A circuit board on which a ROM or the like is mounted is incorporated. On the image plane side of the photographic lens 8, an iris for adjusting the amount of incident light, a mechanical shutter, an optical low-pass filter, and a CCD image sensor 20 are arranged in this order. The motor that moves the lens holding frame in the optical axis direction includes an autofocus motor (hereinafter referred to as an AF motor) that moves the focusing lens and a zoom motor that moves the zoom lens. The AF motor, zoom lens motor, iris The driving of each motor is controlled by a motor controller. The CCD image sensor 20 has, for example, 720 pixels in the vertical direction and 960 pixels in the horizontal direction, and is arranged perpendicular to the optical axis of the photographing lens 8. The sub circuit board provided with the CCD image sensor 20 is connected to the main circuit board via a flexible circuit board. In addition to the ROM, the motor controller is provided on the main circuit board. Note that the CCD image sensor 20 is not limited to one having 720 pixels vertically and 960 pixels horizontally.

  A camera body side mount portion 12 for fitting a lens barrel side mount portion 15 formed in the lens barrel 4 is formed on the front surface of the camera body 3. Near the camera body side mount portion 12, a mount release button 14 that is pressed when the lens barrel 4 is removed from the camera body 3 is provided. By pressing the mount release button 14, the lens barrel 4 is attached to the camera. It can be separated from the body-side mount portion 12.

  For example, three bayonet claws are formed on the lens barrel side mount portion 15, and bayonet engagement claws corresponding to the bayonet claws on the lens side are formed on the camera body side mount portion 12. The lens barrel side mount portion 15 is provided with a plurality of contacts (not shown), and the camera body side mount portion 12 is provided with a terminal (not shown) that contacts the connection terminal. These contacts and terminals enable wired communication together with a serial I / F which will be described later, and when the lens barrel 4 is mounted on the camera body 3, the lens barrel 4 and the camera body 3 are electrically connected to each other. It will be connected to.

  On the back of the camera body 3, a liquid crystal panel for displaying a through image or a menu image of a subject, a display button for switching the liquid crystal panel on / off, and a menu image displayed on the liquid crystal panel are displayed. A cross operation button that is operated when an item is selected, an execution button that is pressed when a menu screen is displayed or confirmed, and the like are provided. By operating the mode dial 6, the digital camera 2 can be sequentially switched to a still image shooting mode, a moving image shooting mode, a night shooting mode, a strobe shooting mode, an adjustment mode for adjusting the direction of a distance measuring sensor, which will be described later, and the like. it can.

  A lens hood 17 for removing harmful light is detachably attached to the front end of the lens barrel 4. The lens hood 17 is attached to the front end portion of the lens barrel 4 via a bayonet mechanism, whereby the lens hood 17 is attached to the lens barrel 4 with high accuracy. A connection terminal 18 is provided on the outer periphery of the front end of the lens barrel 4, and an output terminal (transmission means) described later that contacts the connection terminal 18 is provided on the lens hood 17. The lens hood 17 is connected to the lens barrel 4 by these connection terminals 18 and output terminals.

  The lens hood 17 is provided with a distance measuring sensor 90, a light control sensor 92, and a flash device 94, and each is exposed to the front side of the lens hood 17. As will be described later, the distance measuring sensor 90 includes a condenser lens, an imaging lens that divides subject light from the condenser lens into two, and a line sensor that receives subject light from each imaging lens. An imaging lens is arranged on the side, and a line sensor is arranged on the image plane side of each imaging lens.

  As shown in FIG. 3, the lens hood 17 includes a light control sensor 92, a flash device 94, an adjustment mechanism 95, and the like. The flash device 94 is provided with a light emitter, and the drive of the flash device 94 is controlled by a light emission control circuit provided in the lens barrel 4. The distance measuring sensor 90 and the light control sensor 92 are exposed on the front surface of the lens barrel 4, so that the sensors are not blocked by the user's hand.

  The distance measuring sensor 90 includes a pair of imaging lenses 90a and a pair of line sensors 90b arranged corresponding thereto, and receives a light beam from the imaging lens 90a and outputs a pixel signal from the line sensor 90b. The Pixel signals from the line sensor 90 b are input to the signal processing circuit 91.

  In the signal processing circuit 91, the pixel signal from the line sensor 90b is processed to form digitized distance measurement data. The distance measurement data is transmitted to the lens barrel 4 side through the output terminal 91.

  The adjustment mechanism 95 includes, for example, a servo motor for panning the distance measuring sensor 90, and the driving of the servo motor is controlled by an adjustment circuit described later so that the direction of the distance measuring sensor 90 is the direction of the photographing lens. Adjustment is performed in a first direction perpendicular to the optical axis and in a second direction perpendicular to the optical axis direction and the first direction. The distance measuring sensor 90 is panned in the first direction and the second direction to be appropriate, and thus it becomes possible to focus on a desired subject.

  The lens barrel 4 includes a CCD image sensor 20, an analog signal processing circuit 22, a timing generator (TG) 21, SDRAM 24, a lens barrel CPU 26, a digital processing circuit 28, a serial interface (hereinafter referred to as serial I / F). ) 33, ROM 34, wireless communication interface (hereinafter referred to as wireless communication I / F) 38, AF arithmetic circuit 39, AE arithmetic circuit 40, dimming circuit 41, control circuit 43, sub battery control circuit 48, sub battery 50, etc. Is provided.

  The electric power of the sub battery 50 is supplied to each part of the lens barrel 4 by the sub battery control circuit 48. When the lens barrel 4 is attached to the camera body 3, power from the camera body 3 is supplied to the sub battery 50 through the mount, and is supplied from the sub battery 50 to each part of the lens barrel 4. When the lens barrel 4 is separated from the camera body 3, the lens barrel 4 is driven based on the electric power stored in the sub battery 50.

  The CCD image sensor 20 that converts the light flux from the photographing lens 4 into an electrical pixel signal by photoelectric conversion is controlled by a drive pulse supplied from the TG 21. The analog signal processing circuit 22 includes a correlated double sampling circuit, an amplification 8 circuit, an A / D conversion circuit, and the like. The pixel signal is converted into an RGB analog signal for each cell of the CCD image sensor 20 by the correlated double sampling circuit, and the RGB analog signal is amplified by the amplifier circuit. The RGB analog signal is digitized by an A / D conversion circuit to form 12-bit RAW data per pixel. The formed RAW data is temporarily stored in the SDRAM 24.

  In the digital processing circuit 28, the RAW data for one screen read from the SDRAM 24 is compressed to form 8-bit luminance color difference data (hereinafter referred to as YC data) per pixel. The formed YC data is temporarily stored in the SDARM 24.

  The serial I / F 33 controls data communication performed via the lens barrel side mount unit 15 when the lens barrel 4 is mounted on the camera body 3. Further, the wireless communication I / F 38 receives a connection request signal from the camera body 3, performs connection negotiation with the camera body 3, and establishes a wireless communication line with the camera body 3. YC data and image data stored in the SDRAM 24 described later are transmitted to the camera body 3 side via the serial I / F 33 or the wireless communication I / F 38.

  The AE arithmetic circuit 40 determines the brightness of the subject, and determines the shutter speed, the aperture value, and the like based on the determination. For determining the luminance of the subject, an image signal from the CCD image sensor 20 or a luminance signal from the light control sensor 92 is used. When the lens hood 17 is attached, the luminance signal from the light control sensor 92 is preferentially used.

  The AF calculation circuit 39 calculates a focus shift amount (hereinafter referred to as a defocus amount) from distance data formed based on the pixel signal from the line sensor 90b. The AF motor is driven based on the calculated defocus amount, and the subject is focused.

  The dimming circuit 41 detects the luminance of the subject based on the luminance signal from the dimming sensor 92 provided in the lens hood 17 and controls the driving of the flash device 94 based on the detected luminance of the subject. . The dimming circuit 41 is set with a first threshold value and a second threshold value larger than the first threshold value. When the luminance of the subject is equal to or lower than the first threshold value, strobe light having a large light amount is emitted. Further, when the luminance of the subject is greater than the first threshold and less than or equal to the second threshold, auxiliary light having a light amount smaller than the strobe light is irradiated, and when the luminance of the subject is greater than the second threshold, the flash device The drive of 94 is stopped.

  The SDRAM 24 is a photographing lens between the TELE end and the WIDE end in the adjustment mode in which the orientation of the distance measuring sensor 90 is adjusted in addition to the distance data formed based on the YC data and the pixel signal from the line sensor 90b. 8 position information and information related to the direction of the line sensor 90b in response to the subject are stored as initial information.

  The ROM 34 is composed of, for example, an EEPROM (Electrically Erasable Programmable ROM) which is a nonvolatile memory, and includes format data indicating the model of the lens barrel 4, serial number data indicating the serial number of the lens barrel 4, and various programs. In addition, adjustment data corresponding to the initial information stored in the SDRAM 24 is stored. The adjustment data is for adjusting the direction by moving the distance measuring sensor 90 in the first direction or the second direction, and is read by the lens barrel CPU 26 in the adjustment mode.

  The control circuit 43 controls driving of the adjustment mechanism 95. The control circuit 43 calculates the drive amount of the servo motor provided in the adjustment mechanism 95 based on the adjustment data read from the ROM 34, and drives the servo motor based on the calculated drive amount to measure the distance sensor. Adjust the orientation of 90.

  The camera body 3 includes a strobe control circuit 53, a display control circuit 54, a liquid crystal panel 55 as an electronic display, a CPU 58, a ROM 61, an SDRAM 62, a media controller 64, a digital processing circuit 67, a compression processing circuit 68, a communication control unit 73, A wireless communication I / F 74, a serial I / F 76, a mount detection unit 77, a battery control circuit 80, a battery 82, and the like are provided.

  The ROM 61 is composed of, for example, a non-volatile flash memory, and stores various programs for controlling the camera body 3, and the CPU 58 reads and executes appropriate programs from the ROM 61 as appropriate. In addition, the CPU 58 also performs control of the media controller 64 that writes image data to the recording medium 65, control of the display control circuit 54 that controls driving of the liquid crystal panel 55, and the like.

  The CPU 58 accesses the ROM 34 of the lens barrel 4 to read data, and temporarily stores the read data in the SDRAM 62. For example, when the lens barrel 4 is attached to the camera body 3, the CPU 58 reads the model and serial number data of the lens barrel 4 from the ROM 34. The data read from the ROM 32 is written in the SDRAM 62 of the camera body 3, and the type, serial number, etc. of the lens barrel 4 are registered, so that a plurality of lens barrels 4 can be used properly.

  The media controller 64 accesses the recording medium 65 inserted into a card slot (not shown), and writes data to the recording medium 65 and reads data from the recording medium 65.

  The mount detection unit 77 detects the voltage of the sub-battery 50 of the lens barrel 4, determines that the lens barrel 4 is attached to the camera body 3 when the voltage is detected, and determines that the lens mirror is not detected when the voltage is not detected. It is determined that the tube is separated from the camera body 3.

  The wireless communication I / F 74 establishes a wireless communication line by performing connection negotiation with the wireless communication I / F 38 on the lens barrel 4 side. As a result, YC data signals can be received from the lens barrel 4 and various command signals can be wirelessly transmitted to the lens barrel 4. Examples of the command signal include a shooting command signal for instructing the lens barrel 4 to acquire YC data, and a command signal for instructing adjustment of the direction of the lens hood.

  The communication control unit 73 turns on the serial I / F 76 and turns off the wireless communication I / F 74 according to the mount detection signal from the mount detection unit 77. When the mount detector 77 does not detect the mount of the lens barrel 4, the serial I / F 76 is turned off and the wireless communication I / F 74 is turned on. When the wireless communication I / F 74 is turned on by the communication control unit 73, a connection request signal is transmitted from the wireless communication I / F 74 to the lens barrel 4, and a wireless communication line is established. After establishing the wireless communication line, data is transmitted from the lens barrel 4 to the camera body 3 via wireless communication.

  The strobe control circuit 53 controls the driving of the light emitting unit 7. When the mount detector 77 detects that the lens barrel 4 is separated from the camera body 3, or when the flash device 94 of the lens barrel 4 is set to the priority state, the strobe control circuit 53 emits light. The drive of the unit 7 is prohibited. When the driving of the light emitting unit 7 is prohibited, a mark indicating that the light emission is prohibited is displayed on the liquid crystal panel 55 to notify the user.

  The display control circuit 54 displays an image on the liquid crystal panel 55. For example, when the mode dial 6 is set to the shooting mode, a through image in which the subject image is intermittently updated at a predetermined frame rate is displayed on the liquid crystal panel 55. When the mode dial 6 is set to the adjustment mode, an image for adjusting the direction of the line sensor is displayed based on the distance data from the line sensor 90b.

  Next, the adjustment of the direction of the distance measuring sensor 90 will be described with reference to FIGS. As shown in FIG. 4, when adjusting the direction of the distance measuring sensor 90, the user places the object 100 for adjustment away from the digital camera 2 by a predetermined distance. For example, a subject in which a circular mark 100b is drawn on a flat plate surface is used, and the circular mark is colored black. When the mode dial 6 is set to the adjustment mode, a setting screen on which the liquid crystal panel 55 sets the distance to the subject 100 is displayed, and the distance to the subject 100 is registered by the user. In the above description, a plate on which a circular black mark is drawn is used as an object for preparation. However, an object with clear contrast may be used.

  As shown in FIG. 5, when the distance to the subject 100 is set, the subject image 111 formed based on the pixel signal from the CCD image sensor 20 is displayed on the liquid crystal panel 55. The user places the digital camera 2 so that the subject image 111 matches the aiming mark 110 displayed at the center of the liquid crystal panel 55.

  As shown in FIG. 6, when the execution button 114 is pressed after the digital camera 2 is placed so that the subject image is positioned at the center of the liquid crystal panel 55, the image is formed based on the pixel signal from the line sensor 90b. A subject image 116 and an adjustment image 118 are displayed on the liquid crystal panel 55. A center mark 120 for aligning the subject image 116 is displayed at the center of the adjustment image 118. At this time, the position information of the photographing lens 8, the direction information of each line sensor 90b, and the like are stored in the SDRAM 24 as initial information.

  When the user operates the cross operation button 112, the subject image 116 is aligned with the center mark 120, and when the execution button 114 is pressed in this state, the adjustment data is read from the ROM 34 based on the initial value stored in the SDRAM 24. It is. The adjustment data read from the ROM 34 is stored in the ROM 34 in advance at the time of shipment, and is read according to the pressing of the execution button 114. The control circuit 43 calculates the drive amount of the servo motor based on the read adjustment data, and the servo motor is driven based on the calculated drive amount to adjust the direction of the distance measuring sensor 90. When the execution button 114 is pressed with the subject image 116 off the center mark 120, the drive amount of the servo motor is determined based on the arrangement of the subject image 116 and the center mark 120 on the adjustment screen. The direction of the distance measuring sensor 90 is calculated and adjusted, and the focus is adjusted at a position shifted from the optical axis of the photographing lens 8.

  Thus, since the adjustment screen for adjusting the direction of the distance measuring sensor 90 is displayed on the liquid crystal panel 55, the direction of the distance measuring sensor 90 can be easily adjusted. In addition, since the orientation of the distance measuring sensor 90 can be adjusted according to the distance to the subject, the subject can be accurately focused even when the subject is located at a long distance or at a short distance. become. Further, since the adjustment is performed after the lens hood 17 is actually attached to the lens barrel 4, even if an error occurs in the attachment of the lens hood 17 to the lens barrel 4, the subject is surely focused. Can do.

  The lens hood may be provided with an ultraviolet sensor for detecting the intensity of ultraviolet rays. By providing a UV sensor on the lens hood and a determination unit for determining whether the lens barrel is outdoor or indoor based on the measurement signal from the UV sensor, it is possible to determine whether it is indoor or outdoor. The sensitivity of the distance measuring sensor can be switched outdoors.

  Further, the adjustment of the lens hood 17 described above can be executed even when the lens barrel 4 and the lens hood 17 attached to the lens barrel 4 are separated from the camera body 3. The YC data formed based on the pixel signal from the CCD image sensor 20 and the image data formed based on the pixel signal from the line sensor 90b are transmitted from the lens barrel 4 to the camera via the wireless communication I / F 38, 74. It is transmitted to the main body 3. When the adjustment operation on the adjustment screen displayed on the liquid crystal panel 55 of the camera body 3 is finished and the execution button is pressed by the user, an adjustment execution signal is transmitted from the camera body 3 to the lens barrel 4, Accordingly, the adjustment mechanism 95 adjusts the direction of the distance measuring sensor 90. As described above, even when the lens barrel 4 is separated from the camera body 3, the direction of the distance measuring sensor 90 can be adjusted, and a highly convenient digital camera can be provided.

  In the above embodiment, a digital camera that mainly captures still images of a subject has been exemplified. However, the present invention is not limited to this, and may be applied to a video camera that mainly captures moving images.

  In the above embodiment, the output terminal is exemplified as the transmission means. However, the transmission means for transmitting the distance data is not limited to this, and the modulation unit that modulates the distance data and forms the transmission signal and the transmission signal are transmitted. It may be a wireless communication interface having an antenna.

It is the perspective view which observed the digital camera of the present invention from the front. It is the perspective view which separated the lens hood, the lens barrel, and the camera body. It is a block diagram of the whole digital camera. It is a general view at the time of adjusting the arrangement of the distance measuring sensor. It is explanatory drawing which observed the liquid crystal panel on which the adjustment screen for adjusting arrangement | positioning of a ranging sensor was displayed. It is explanatory drawing which adjusts the direction of a ranging sensor using an adjustment screen. It is the flowchart which showed the procedure at the time of adjusting the direction of a ranging sensor.

Explanation of symbols

2 Digital camera (camera)
DESCRIPTION OF SYMBOLS 3 Camera body 4 Lens barrel 12 Camera body side mount part 15 Lens barrel side mount part 17 Lens hood 20 CCD image sensor 24 SDRAM
26 Lens barrel CPU
35 ROM
38 Wireless communication I / F
43 Control circuit 55 LCD panel 74 Wireless communication I / F
90 Distance sensor 91 Output terminal (Transmission means)
92 Light control sensor 94 Flash device 95 Adjustment mechanism 112 Cross operation button 114 Execution button

Claims (5)

In the lens hood that is detachably attached to the tip of the lens barrel,
A distance measuring sensor that receives a pair of subject light respectively by a light receiving element and converts it into distance information;
A lens hood comprising: transmission means for transmitting distance information acquired by the distance measuring sensor to the outside.   The lens hood according to claim 1, wherein the distance measuring sensor receives reflected light from a subject to acquire the distance information, and includes a flash device that irradiates the subject with light.   The lens hood according to claim 2, further comprising a light control sensor for adjusting a light emission level of the flash device.   4. The lens hood according to claim 1, further comprising an ultraviolet sensor for measuring the intensity of ultraviolet rays from the subject.   5. A camera comprising: a lens hood that is detachably attached to the lens hood according to claim 1; and an adjusting unit that adjusts the direction of the distance measuring sensor in response to distance information from the lens hood. .

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