JP2018194751A - Optical apparatus and photographing apparatus - Google Patents

Abstract

An optical apparatus capable of reducing ghosts and flares caused by light emission of an optical sensor without increasing the size of the apparatus and design restrictions. An optical element holding frame that holds at least one optical element, and a light projecting unit that is attached to the fixing member, and has a fixing member that holds the optical element holding frame so as to be relatively movable. A light sensor having a light receiving portion; and a light shielding plate provided integrally with the optical element holding frame. The light shielding plate is inserted into and removed from the optical sensor along with the movement of the optical element holding frame. In the optical apparatus in which the relative position of the element holding frame is detected, the light shielding plate is provided with a region having a light reflectance lower than that of the optical element holding frame. [Selection] Figure 5

Description

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

  In optical devices such as video cameras and interchangeable lenses, some optical elements are provided so as to be movable in a lens barrel in order to arbitrarily change zooming, focusing, and other optical characteristics. In these lens barrels, the optical element is fixed and held integrally with the optical element holding member, and the optical element holding member moves relative to the fixed member in the lens barrel by an external force that passes through the actuator or the operating ring. It becomes.

  In these optical devices, as a means for detecting the relative position of the optical element, a photo interrupter as an optical sensor having a light receiving element and a light emitting element is provided on a fixed member, and a light shielding wall integrally provided on the movable member is provided between the sensors. A mechanism for inserting and removing is known.

  The light shielding wall provided integrally with the movable member and the movable member is generally a black mold or metal. In general, a general photo interrupter has a light emitting element that emits visible light or near infrared light and a light receiving element that is sensitive to light emitted from the light emitting element. is there.

  On the other hand, in recent years, image sensors provided in these optical devices have been adapted to high sensitivity and infrared in order to adapt to dark place photography, and so on. There is a problem that a ghost is generated in a captured image by reaching the image sensor. In particular, the tendency becomes prominent when the movable member and the light shielding wall provided integrally with the movable member are a mold in which a glass filler or the like is mixed as a reinforcing material.

  In order to solve this problem, in order to prevent the light-shielding wall from being seen from the image pickup device, arrangement of the photo interrupter with respect to the image pickup device and provision of a light shielding wall to prevent detection light from entering the image pickup device are provided. Has been.

  In patent document 1, it has an isolation wall which demarcates an optical sensor from the movement space of a lens frame, and demarcates the accommodating part which accommodates the said optical sensor, and the said to-be-detected piece has the said to-be-detected piece with respect to the said accommodating part. The problem is solved by having an insertion / removal port that can be inserted / removed.

Japanese Patent No. 4689390

  However, providing such an isolation wall or isolating the photo interrupter from the moving space has a problem that the degree of freedom in design is reduced and the apparatus is increased in size.

In order to solve the above problems, an optical instrument according to the present invention is
An optical element holding frame for holding at least one or more optical elements;
Having a fixing member that holds the optical element holding frame so as to be relatively movable;
An optical sensor having a light projecting part and a light receiving part attached to the fixing member;
Having a light shielding plate provided integrally with the optical element holding frame;
In the optical apparatus in which the light shielding plate is inserted into and removed from the optical sensor with the movement of the optical element holding frame, and the relative position between the fixing member and the optical element holding frame is detected.
The light shielding plate is provided with a region having a light reflectance lower than that of the optical element holding frame.

  According to the optical apparatus of the present invention, it is possible to reduce ghosts and flares caused by the light emission of the optical sensor without increasing the size of the apparatus and design restrictions.

1 is a block diagram of an optical apparatus according to a first embodiment of the present invention. 1 is a partially exploded perspective view of an optical apparatus according to Embodiment 1 of the present invention. The figure which shows the optical sensor and light-shielding wall in Example 1 of this invention The figure which shows the positional relationship of the optical sensor and light-shielding wall in Example 1 of this invention, and the relationship of the output value obtained from an optical sensor. The enlarged detail drawing of the light-shielding wall in Example 1 of this invention The partial exploded view of the light-shielding wall in Example 1 of this invention Partial detail drawing of the optical filter insertion / extraction mechanism in Example 2 of this invention The figure which shows the filter holder of the optical filter insertion / extraction mechanism in Example 2 of this invention, an optical sensor, and an image pick-up element.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Example 1]
FIG. 1 is a block diagram of an imaging apparatus as an optical apparatus according to the first embodiment. The imaging device includes a digital video camera, a digital still camera, a surveillance camera, and the like. FIG. 2 is a partially exploded perspective view of the lens barrel of the imaging apparatus shown in FIG.

  1 and 2, L1 is a first lens unit having a positive refractive power that is fixed during zooming.

  L2 is a second lens unit having a negative refractive power as a variable power lens unit (zoom lens unit) that performs a variable power operation by moving in the optical axis OXZ direction indicated by an arrow.

  L3 is a third lens unit having a fixed positive refractive power.

  L4 is a fourth lens group as a focus lens group having a positive refractive power that performs focus adjustment by moving in the optical axis direction OXF indicated by an arrow. The first lens unit L1 to the fourth lens unit L4 constitute an optical axis OX including a photographing optical system, an optical axis OXZ, and an optical axis OXF.

  Reference numeral 1 denotes a front lens barrel that holds the first lens unit L1.

  Reference numeral 2 denotes an optical element holding frame that holds the second lens unit L2 as an optical element, and is supported by two guide bars 102 and 103 provided in a rear lens barrel frame 101 as a fixing member shown in FIG. Yes. The guide bar 102 passes through a guide hole 202 provided in the optical element holding frame 2 and is fixed to the front lens barrel frame 301 at one end. Similarly, the guide bar 103 is fixed to the front lens barrel frame 301 through a groove 203 provided in the optical element holding frame 2. With this configuration, the optical element holding frame 2 is configured to be relatively movable in the optical axis direction OXZ between the front lens barrel frame 101 and the rear lens barrel frame 101.

  Reference numeral 8 denotes a zoom motor as drive means (actuator) for driving the second lens unit L2, and a stepping motor is employed in this embodiment. Reference numeral 8a denotes a lead screw, which is arranged coaxially with the rotor constituting the stepping motor 8 and parallel to the optical axis. A rack member 7 installed on the optical element holding frame 2 that is guided and held so as to be freely movable in the optical axis direction OXZ meshes with the lead screw 8a serving as a feed screw, and the optical element holding frame 2 is rotated by the rotation of the rotor. Moves in the optical axis direction OX.

  Reference numeral 9 denotes a photo interrupter as a sensor having a light projecting unit and a light receiving unit, and is used as a zoom initial position detection sensor. The photo interrupter 9 is inserted and fixed in a photo interrupter fixing groove 104 provided in the rear lens barrel frame 101 and is integrally held by the rear lens barrel frame 101.

  A light shielding plate 204 is used as a light shielding plate zoom initial position detection sensor provided integrally with the optical element holding frame 2. The light shielding plate 204 is inserted and removed between the light receiving element and the light projecting element of the photo interrupter 9 as the optical element holding frame 2 moves in the optical axis direction. By inserting / removing the light shielding plate 204, the photo interrupter 9 electrically detects the light shielding / transmission switching of the light from the light emitting element, and the optical element holding frame 2 and the rear lens barrel frame 101 are relative to each other in the optical axis direction. Detect the reference position.

  Reference numeral 3 denotes a fixing member that holds the third lens unit L3.

  Reference numeral 4 denotes a second moving member as a focus lens holding frame that holds the fourth lens unit L4. The second moving member 4 is fixed with a substantially square cylindrical air core coil 10 and a flexible printed circuit board 104 for energizing the coil 10.

  Reference numeral 6 denotes an aperture device that changes the aperture diameter of the optical system, and is a guillotine aperture device that changes the aperture diameter by moving two aperture blades in opposite directions by the drive unit 6.

  Reference numeral 34 denotes an aperture sensor that detects the rotational position of the drive magnet of the aperture drive unit 6 with a Hall element.

  The imaging means 30 comprising a CCD or CMOS, a low-pass filter, an infrared cut filter or the like is fixedly held by a rear barrel 101 shown in FIG. The imaging means 30 photoelectrically converts an optical image formed by the photographing optical system to generate a photographing signal and outputs it to the camera signal processing circuit 31.

  Yokes 11 and 12 and a magnet 13 are fixed to the rear barrel 101. The yoke 11 has a U-shaped cross section and extends in the optical axis direction. A magnet 13 is held inside the yoke 11. An air core portion of the coil 10 is inserted into the yoke 11, and the coil 10 is separated from the yoke 11 and the magnet 13. The magnet 13 is magnetized in a direction perpendicular to the optical axis and extends in the optical axis direction. A yoke 12 is held at the open end of the yoke 11. The coil 10, the yokes 11 and 12, and the magnet 13 constitute a voice coil motor (VCM or linear actuator). The second moving member is configured to be movable in a predetermined direction (optical axis direction) by the voice coil motor.

  The camera signal processing circuit 31 performs signal processing such as predetermined amplification and gamma correction on the output of the imaging means 30. The signal processed by the camera signal processing circuit 31 is output to a microcomputer 32.

  The microcomputer 32 takes in many signals and performs signal processing. In addition, a large number of signals are output in accordance with the input signal to control the optical device. For example, the microcomputer 32 outputs an aperture driving signal output to the aperture driving means in accordance with an input signal from the camera signal processing circuit 31 and an input signal such as the rotation amount of the aperture driving unit from the aperture sensor 34 to adjust the light amount. Do.

  Reference numeral 33 denotes a recording means for recording an image signal processed by the microcomputer 32 and other recording conditions.

  50 is a zoom switch for instructing a zooming operation, 51 is a focus switch for instructing a manual focus operation (focusing operation) consciously by the photographer, and 52 is a power switch.

  When the power switch 52 is turned on, the zoom motor 8 receives a drive signal from the zoom drive circuit 35 by a signal from the microcomputer 32. Then, the photo interrupter 9 detects the initial position, and the first moving member 2 moves to a predetermined position and stands by.

  The zoom motor 8 is subjected to position control corresponding to the operation of the zoom switch 50 by the number of steps from the initial position. When the zoom switch 50 is operated, the microcomputer 32 determines in which direction the movement direction is operated, and the zoom operation is performed.

  On the other hand, when the coil 10 is energized from the flexible printed board 104 to the focus drive circuit 36, the second moving member 4 is driven in the optical axis direction by the action of the magnetic circuit constituted by the yokes 11, 12 and the magnet 13. The second moving member 4 detects the detected surface of the scale 20 having a detection surface fixed to the second moving member 4 with an adhesive and the scale 20 mechanically fixed to the rear barrel 101, and detects an electric signal. The position of the second moving member 4 is detected by the sensor 21 that generates FIG. 3 is a diagram showing the positional relationship between the photo interrupter 9 provided in the rear barrel 101 and the light shielding plate 204 provided integrally with the optical element holding member 2 in connection with the implementation of the present invention. For ease of illustration, the rear barrel 101 is not shown.

  The photo interrupter 9 is provided with a light emitting unit 91 and a light receiving unit 92, respectively, and a state where the light receiving unit 92 detects light from the light emitting unit 91 and a light shielding plate 204 enter between the photo interrupters 9, and from the light emitting unit 91. It can be seen that it is possible to distinguish between two states in which the light receiving unit 92 cannot detect this light.

  FIG. 4 is a detailed diagram illustrating the output voltage V obtained from the photo interrupter 9 with respect to the relative position d of the optical element holding member 2 and the fixing member 101 in the embodiment of the present invention.

  An example in which the optical element holding member 2 moves from the WIDE end to the TELE end will be described with reference to FIG. First, according to FIG. 4, it can be seen that from the WIDE end to the WIDE region, the light shielding plate 204 enters between the photo interrupters 9 and the light receiving unit 92 cannot detect the light from the light emitting unit 91, and is in the Lo state of 501. Further, according to FIG. 4, when the relative position of the optical element holding member 2 and the fixing member 101 changes to the TELE side, the light shielding plate 204 is inserted into and removed from the photo interrupter 9, and the output from the photo interrupter changes from Lo to High. It turns out that it will be in the state 502 which changes. Further, according to FIG. 4, when the relative position of the optical element holding member 2 and the fixing member 101 advances from the reference position to the TELE side, the light shielding plate 204 is sufficiently detached from the photo interrupter 9 and the output from the photo interrupter becomes High 503. I understand. In the embodiment of the present invention, the relative positional relationship between the optical element and the fixing member 101 is detected at a position 502 shown in FIG. 4, and the position is set as a reference position.

  FIG. 5 is a view of the direction of the arrow D shown in FIG. 3, that is, the photo interrupter viewed from the light emitting element side.

  According to FIG. 5, the light shielding plate 204 is provided with an antireflection treatment 205 as a region having a lower reflectance than the optical element holding member 2. Further, FIG. 5 shows a state where the light shielding plate is interposed between the photo interrupters 9. At this time, the light emitted from the light emitting unit 91 of the photo interrupter 9 hits a region having a lower reflectivity applied to the light shielding plate 204, and the light to the light receiving unit of the photo interrupter is blocked and outputs Lo as described above.

  FIG. 6 is a detailed view in which an antireflection treatment is performed as a region having a low light reflectance by the light shielding plate 204 provided integrally with the optical element holding member 2. According to FIG. 6, the light shielding plate 204 is provided with a concave region as a region for performing an antireflection treatment. An antireflection treatment can be performed by sticking a light shielding sheet 205a to the concave area. Further, light that hits a region having a lower reflectance applied to the light shielding plate 204 is absorbed, and the absolute amount scattered as stray light in the optical device is reduced.

  In the practice of the present invention, the light shielding plate 204 is provided with a recess as a more preferred embodiment. However, the present invention is not limited thereto, and the present invention can be implemented and its effect provided that the light shielding plate is subjected to antireflection treatment. In addition, any antireflection sheet for carrying out the present invention can obtain the effects of the present invention as long as it has a lower reflectance than the optical element holding member. However, Actar's Spectra Black and Somar Corporation's Soma black and the like are more preferable.

[Example 2]
FIG. 7 is a transmission diagram of an infrared cut filter insertion / removal mechanism as an imaging unit included in the optical apparatus according to the second embodiment.

  According to FIG. 7, an infrared cut filter 162 as an optical element, a filter folder 163 as an optical element holding frame for holding the infrared cut filter, and a fixing member for holding the optical element pulling frame so as to be relatively movable. It consists of a CCD folder 164. Further, according to FIG. 7, a photo interrupter 165 as an optical sensor having a light projecting part and a light receiving part is provided in the CCD folder, and the light shielding plate 166 and the optical element holding frame are moved relative to the fixed member in the optical element holding frame. It can be seen that an actuator 167 is provided as a means for this. In the infrared cut filter insertion / removal mechanism, the filter folder 163 is moved in a direction X substantially orthogonal to the optical axis OX of the optical device by the force generated in the actuator 167, and the infrared cut filter 162 is inserted / removed with respect to the optical axis OX of the optical device. To do. Further, in the infrared cut filter insertion / removal mechanism, the light shielding plate 166 provided in the filter folder 163 is inserted into / removed from the photo interrupter 165 provided in the CCD folder 164, and the change in the signal of the photo interrupter and the light of the infrared cut filter are detected. The insertion and removal with respect to the shaft are linked.

  FIG. 8 is a schematic transmission diagram of the filter folder 163, the photo interrupter 165, and the CCD 167 as an image pickup device of an optical device. The CCD folder is not shown for easier understanding of the present invention. A part of the light shielding plate 166 provided in the filter folder 163 is baked with black paint so that an area having a lower reflectance than the filter folder 163 as an optical element holding frame is provided, and the light from the photo interrupter 165 is shielded by the light shielding plate. It can be seen that unnecessary diffusely reflected light P reaching the image sensor 167 is prevented.

1 Front lens barrel 2 Optical element holding frame

Claims (3)

An optical element holding frame for holding at least one or more optical elements;
Having a fixing member that holds the optical element holding frame so as to be relatively movable;
An optical sensor having a light projecting part and a light receiving part attached to the fixing member;
Having a light shielding plate provided integrally with the optical element holding frame;
In the optical apparatus in which the light shielding plate is inserted into and removed from the optical sensor with the movement of the optical element holding frame, and the relative position between the fixing member and the optical element holding frame is detected.
An optical apparatus, wherein the light shielding plate is provided with a region having a light reflectance lower than that of the optical element holding frame.   2. The optical apparatus according to claim 1, wherein a region having a light reflectance lower than that of the optical element holding frame provided on the light shielding plate has a light absorption characteristic higher than that of the optical element holding frame.   2. The optical apparatus according to claim 1, wherein a region having a light reflectance lower than that of the optical element holding frame provided on the light shielding plate is provided at least on a light projecting element side of the optical sensor. The optical apparatus described in 1.