JP2008197134A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain malfunction of an interlocking mechanism between a photographic optical system and a finder system, and a finder zoom mechanism. <P>SOLUTION: The camera is equipped with: photographic lenses L1 and L2 guiding subject light to an imaging device 11; a zoom means 222 changing the magnification of the photographic lenses L1 and L2; an optical finder 6 having liquid lenses 61 and 62 as an optical system; and a finder zoom means 9 changing the refractive index of the liquid lenses 61 and 62 interlocked with changing the magnification of the photographic lenses L1 and L2 by the zoom means 222 and changing the magnification of the optical finder 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a camera having an optical viewfinder including a liquid lens.

2. Description of the Related Art Conventionally, a camera that changes the magnification of a finder optical system in conjunction with the change of the magnification of a photographing optical system is known (for example, Patent Document 1).
JP 2003-222932 A

  However, the interlocking mechanism between the photographing optical system and the finder system and the finder zoom mechanism are complicated.

The camera according to the first aspect of the present invention is a photographic lens for guiding subject light to the image sensor, a zoom means for changing the magnification of the photographic lens, an optical viewfinder having a liquid lens in the optical system, and a magnification of the photographic lens by the zoom means. A finder zooming unit that changes the refractive index of the liquid lens in conjunction with the change and changes the magnification of the optical finder is provided.
According to a second aspect of the present invention, in the camera according to the first aspect, the liquid lens is fixed at a predetermined position in the optical viewfinder.
According to a third aspect of the present invention, in the camera according to the first or second aspect, the finder zoom means changes the refractive index of the liquid lens by using kinetic energy generated when the photographing lens is moved by the zoom means. And
According to a fourth aspect of the present invention, in the camera according to any one of the first to third aspects, the optical finder has two groups of liquid lenses, and the finder zooming means reciprocally compares the internal pressures of the liquid lenses. It is characterized by increasing or decreasing.
According to a fifth aspect of the present invention, in the camera according to any one of the first to fourth aspects, the finder zoom means includes a piston and a cylinder, and the cylinder drives the inside of the cylinder in conjunction with the movement of the photographing lens. It is characterized by doing.

  According to the present invention, since the refractive index of the liquid lens can be changed to change the magnification of the optical viewfinder, the mechanism can be simplified.

A digital camera according to an embodiment will be described with reference to FIGS.
FIG. 1 is a front perspective view of a digital camera according to an embodiment. The camera body 1 is provided with a lens barrel 2, a power switch 3, a release button 4, a viewfinder 6, and a zoom up button 7 and a zoom down button 8 for changing the magnification of the photographing optical system. The lens barrel 2 is a retractable lens barrel that is extended from the camera body 1 in the optical axis direction in response to an ON operation of the power switch 3 and is stored in the camera body 1 in response to an OFF operation of the power switch 3. .

FIG. 2 is a block diagram illustrating a circuit configuration of the digital camera in the embodiment.
When the power switch 3 is turned on, the lens barrel 2 is extended to the photographing position at the wide angle end. Then, the subject light incident through the photographing optical system of the lens barrel 2 is guided to the image sensor 11, and a subject image is formed on the imaging surface. The image sensor 11 is configured by a CCD or CMOS image sensor including a plurality of photoelectric conversion elements corresponding to pixels. The image sensor 11 captures a subject image formed on the imaging surface, and outputs a color photoelectric conversion signal corresponding to the brightness of the subject image. The A / D conversion circuit 12 converts an imaging signal after analog processing performed by an AFE circuit (not shown) into a digital signal.

  The image processing unit 13 is configured, for example, as an ASIC, and performs image processing on the image signal from the image sensor 11. The CPU 14 receives a signal output from each block, performs a predetermined calculation, and outputs a control signal based on the calculation result to each block. The CPU 14 compresses the image data input from the image processing unit 13 by a predetermined method such as JPEG, and records it in the memory card 15 in a format such as EXIF.

  The zoom-up button 7 is an operation button for instructing enlargement of the magnification of the photographing optical system. When the zoom-up button 7 is operated, a zoom-up signal corresponding to the operation amount is output to the CPU 14. The zoom down button 8 is an operation button for instructing the reduction of the magnification of the photographing optical system, and a zoom down signal corresponding to the operation amount is output to the CPU 14. The CPU 14 calculates the driving amount of the lens barrel 2 based on the input zoom-up signal or zoom-down signal, and outputs it to the zoom motor driver 16.

  The zoom motor driver 16 performs drive control of the zoom motor 17 based on the drive amount calculated by the CPU 14. The zoom motor 17 is driven according to a signal from the zoom motor driver 16 and rotates a cam cylinder 22 described later to drive a zoom lens (not shown) in the lens barrel 2 in the optical axis direction. When the CPU 14 receives an ON signal from the power switch 3, the CPU 14 outputs a predetermined driving amount and drives the lens barrel 2 to the photographing position by driving the zoom motor 17. Similarly, when the OFF signal is input from the power switch 3, the lens barrel 2 is retracted and stored.

  The focus motor 25 drives an AF lens (not shown) to the in-focus position based on the focus adjustment state detected by a focus detection device (not shown).

FIG. 3 is a partial cross-sectional view of the camera in a state where the lens barrel 2 is extended to the photographing position. As described above, the lens is extended from the non-photographing position (collapse position) to the photographing position, the magnification at the photographing position is changed (zooming), and the lens barrel is retracted from the photographing position to the non-photographing position. Done as a source. Details of each part will be described below.
In FIG. 3, the finder zoom mechanism 9 zooms the liquid lenses 61 and 62 of the finder 6 in conjunction with the zooming operations of the zoom lenses L1 and L2 of the lens barrel 2. The zoom lenses L1 and L2 are driven by a lens driving mechanism.

-Lens drive mechanism-
The lens driving mechanism will be described with reference to FIG.
The fixed barrel 21 of the lens barrel 2 is fixed to the camera body 1 with screws or the like. On the inner side of the fixed cylinder 21, three sets of two rectilinear grooves, that is, six rectilinear grooves are provided. FIG. 3 shows four straight grooves 21a, 21b, 21c, and 21d for convenience of illustration. A cam cylinder 22 is provided on the inner peripheral side of the fixed cylinder 21. The cam barrel 22 rotates around the optical axis when the driving force of the zoom motor 17 (see FIG. 2) is transmitted to the gear portion 221. The cam cylinder 22 is provided with six cam grooves that are paired with the straight advance groove. As for the cam grooves, four cam grooves 22a, 22b, 22c and 22d are shown for convenience of illustration.

  A first group cylinder 23 is provided on the inner peripheral side of the cam cylinder 22, and three follower pins are provided on the outer periphery thereof. FIG. 3 shows the follower pins 23a and 23b for convenience of illustration. As shown in FIG. 3, the follower pins 23 a and 23 b penetrate the cam grooves 22 a and 22 b of the cam cylinder 22 and engage with the rectilinear grooves 21 a and 21 b of the fixed cylinder 21, respectively. That is, the three follower pins pass through the cam groove of the cam barrel 22 that is paired with each other and engage with the rectilinear groove of the fixed barrel 21. With this cam mechanism, the first group cylinder 23 advances and retracts in the optical axis direction with respect to the cam cylinder 22 and the fixed cylinder 21.

  A first group lens L1 having a negative refractive index is fixed inside the first group cylinder 23, and the first group lens L1 advances and retreats in the optical axis direction together with the first group cylinder 23 with respect to the cam cylinder 22 and the fixed cylinder 21. . On the other hand, a second group lens L2 (convex lens) held by the second group lens frame 24 is provided inside the cam cylinder 22. The two group lens frame 24 is provided with three follower pins. FIG. 3 shows the follower pins 24a and 24b for convenience of illustration. As shown in FIG. 3, the follower pins 24 a and 24 b of the second group lens frame 24 pass through the cam grooves 22 c and 22 d of the cam cylinder 22 and engage with the rectilinear grooves 21 c and 21 d of the fixed cylinder 21, respectively. That is, the three follower pins pass through the cam groove of the cam barrel 22 that is paired with each other and engage with the rectilinear groove of the fixed barrel 21. As a result, the second group lens L2 advances and retracts in the optical axis direction with respect to the cam cylinder 22 and the fixed cylinder 21. Zooming is performed by the advance and retreat of the first group lens L1 and the second group lens L2 with respect to the fixed cylinder 21 as the cam cylinder 22 rotates.

  When zoom-in is instructed by operating the zoom-up button 7, the cam cylinder 21 is rotated clockwise as viewed from the subject side by driving the zoom motor 17, and the first group lens L1 and the second group lens L2 are moved toward the subject side. While moving forward, the distance in the optical axis direction between the first group lens L1 and the second group lens L2 becomes narrower. On the other hand, when zoom down is instructed by operating the zoom down button 8, the cam cylinder 21 rotates counterclockwise as viewed from the subject side by driving the zoom motor 17 in the reverse direction, and the first group lens L 1 and The second group lens L2 moves backward to the user side.

  A focus lens L3 driven by a focus motor 25 is provided behind the first group lens L1 and the second group lens L2. The driving force from the focus motor 25 is transmitted to the focus lens L3 by the feed screw 251. The focus lens L3 is guided from the camera body 1 to the shaft 252 provided so as to project in the optical axis direction, and advances and retreats in the optical axis direction. The subject light that has passed through the first group lens L1 and the second group lens L2 passes through the focus lens L3 and is guided to the image sensor 11, and the focus lens L3 is driven to advance and retract in the optical axis direction by the driving force from the focus motor 25. The focus is adjusted.

-Finder-
Next, the finder 6 will be described in detail with reference to FIGS. As shown in FIG. 4, the finder 6 includes first and second liquid lenses 61 and 62 having a variable refractive index, a Porro prism 63, and an eyepiece lens 64. As shown in FIG. 60. The first liquid lens 61, the second liquid lens 62, and the Porro prism 63 constitute an objective system, and the eyepiece lens 64 constitutes an eyepiece system. The finder 6 is a real image type zoom finder, and its magnification is variable by the finder zoom mechanism 9. The subject light that has passed through the first liquid lens 61 and the second liquid lens 62 is reflected four times by the Porro prism 63 and forms an image on the surface A of the Porro prism 63. The subject image formed on the surface A is observed by the user through the eyepiece lens 64.

  The first liquid lens 61 will be described with reference to FIG. The second liquid lens 62 is similarly configured. In FIG. 5 showing an enlarged view of the first liquid lens 61, the first liquid lens 61 includes a first transparent member 610, a second transparent member 611, and a cylindrical tube member 612. The first transparent member 610 is joined to one end 613 of the tubular member 612, and the second transparent member 611 is joined to the other end 614 of the tubular member 612. The cylindrical member 612 and the first transparent member 610, and the cylindrical member 612 and the second transparent member 611 are joined using, for example, a sealing material, and the lens chamber LC1 is formed inside the cylindrical member 612. The first transparent member 610 and the second transparent member 611 are transparent thin film materials that can be elastically deformed, and the first transparent member 610 and the second transparent member 611 form an optical surface of the first liquid lens 61.

  An injection port 616 is provided on the peripheral surface of the cylindrical member 612, and one end of a flexible conduit 101 is connected to the injection port 616. The other end of the pipe line 101 is connected to one end of a cylinder 911 of a first zoom mechanism 91 described later shown in FIG.

  The lens chamber LC1 is filled with a predetermined amount of liquid 615 having a desired refractive index, for example, water, oil, alcohol or the like. At this time, the first transparent member 610 and the second transparent member 611 are deformed according to the pressure of the liquid 615 filled in the lens chamber LC1. That is, when the liquid 615 is injected into the lens chamber LC1 and pressurized, the first transparent member 610 is deformed to be convex toward the subject side (arrow a1), and the second transparent member 611 is on the user side ( Deforms convexly toward arrow a2). As a result, the first liquid lens 61 is deformed from the concave lens and functions as a convex optical lens. When the pressure in the lens chamber LC1 is reduced, the first transparent member 610 is deformed toward the user side (arrow b1), and the second transparent member 611 is deformed toward the subject side (arrow b2). As a result, the refractive index of the first liquid lens 61 is changed from positive to negative.

  The second liquid lens 62 has the same configuration as the first liquid lens 61. That is, when the liquid 625 injected into the lens chamber LC2 composed of the first transparent member 620, the second transparent member 621, and the cylindrical tube member 622 is pressurized, the positive refractive index increases and the pressure is reduced. Then, the positive refractive index decreases. One end of a flexible conduit 102 is connected to an inlet 626 provided on the peripheral surface of the cylindrical member 622, and the other end of the conduit 102 is one end of a cylinder 921 of a second zoom mechanism 92 described later. It is connected to the.

-Viewfinder zoom mechanism-
In FIG. 3, the finder zoom mechanism 9 includes a first zoom mechanism 91 and a second zoom mechanism 92. The first zoom mechanism 91 includes a cylinder 911, a piston 912, a feed screw 913 that is a piston rod, and a first gear 914, and functions as a pressure adjustment device that adjusts the pressure of the lens chamber LC1 of the first liquid lens 61. The piston 912 is provided inside the cylinder 911 so as to be capable of reciprocating in the left-right direction (the direction of arrows 1 and 2) in FIG. The feed screw 913 is a left screw provided in the piston 912, and a first gear 914 is attached to the tip. The first gear 914 meshes with the gear portion 221 described above and is driven by the rotation of the cam cylinder 22 to drive the piston 912 in the direction of the arrow 1 or 2. The second zoom mechanism 92 has the same configuration as the first zoom mechanism 91 and functions as a pressure adjustment device that adjusts the pressure of the lens chamber LC2 of the second liquid lens 62. The feed screw 923 is a right screw provided on the piston 922, and a second gear 924 is attached to the tip. In FIG. 3, the second gear 924 and the gear portion 221 are not engaged with each other. However, this is for convenience of illustration, and the second gear 924 and the gear portion 221 are similar to the case of the first zoom mechanism 91. I'm engaged.

The operations of the finder 6 and the finder zoom mechanism 9 associated with zooming of the zoom lenses L1 and L2 of the lens barrel 2 will be described with reference to FIG.
When zoom-in is instructed by operating the zoom-up button 7, the CPU 14 drives the zoom motor 17 via the zoom motor driver 16. The driving force of the zoom motor 17 rotates the first gear 914 and the second gear 924 counterclockwise from the gear portion 221. Since the feed screw 913 is a left-hand screw, the piston 912 is driven in the direction of arrow 1 as the first gear 914 rotates counterclockwise as viewed from the subject side. As a result, the liquid 615 in the cylinder 911 is injected into the lens chamber LC1 through the pipe line 101 according to the driving amount of the piston 912, and the lens chamber LC1 is pressurized.

  Since the feed screw 923 integrated with the second gear 924 is a right-hand screw, the piston 922 is driven in the direction of arrow 2 by the counterclockwise rotation of the second gear 924. As a result, the liquid 625 in the lens chamber LC2 is sucked into the cylinder 92 through the conduit 102 in accordance with the driving amount of the piston 922, and the lens chamber LC2 is decompressed. That is, as the cam barrel 22 rotates in the clockwise direction, the pistons 912 and 922 move in opposite directions, so that the internal pressures of the first liquid lens 61 and the second liquid lens 62 increase and decrease in the opposite direction.

  As described above, when the first liquid lens 61 is pressurized and the second liquid lens 62 is depressurized in accordance with the zoom-up operation of the zoom lenses L1 and L2 of the lens barrel 2, the first liquid lens 61 and the second liquid lens 61 are reduced. The curvature of the optical surface of the liquid lens 62 changes to have a shape indicated by a broken line in FIG. As a result, the refractive index of each of the first liquid lens 61 and the second liquid lens 62 changes to change the zoom ratio, so that the optical system of the finder 6 is zoomed up.

  When zooming in from the tele side to the wide side is instructed by operating the zoom down button 8, the driving force of the zoom motor 17 is transmitted to the gear portion 221 and the cam cylinder 22 rotates counterclockwise as viewed from the subject side. The lens chamber LC1 is depressurized and the lens chamber LC2 is pressurized by the operation opposite to the above-described operation, so that the first liquid lens 61 and the second liquid lens 62 have shapes shown by solid lines. As a result, the refractive index of each of the first liquid lens 61 and the second liquid lens 62 changes and the zoom ratio changes, so that the optical system of the finder 6 is zoomed down.

  When the power switch 3 is instructed to turn off the power, the lens barrel 2 is retracted to the non-photographing position via the wide end by the driving force of the zoom motor 17. When the lens barrel 2 is driven from the wide end to the retracted position, a clutch (not shown) is provided so that the drive of the gear unit 221 is not transmitted to the finder zoom mechanism 9, and the gear unit 221, the first gear 914, and the gear unit are provided. 221 and the second gear 924 are separated. Therefore, the curvature of the first liquid lens 61 and the second liquid lens 62 does not change from the curvature in the wide end state.

According to the digital camera according to the embodiment described above, the following operational effects can be obtained.
(1) When a change in photographing magnification is instructed by the zoom up button 7 or the zoom down button 8, the first liquid lens 61 is operated by the finder zoom mechanism 9 in conjunction with the driving of the zoom lenses L1 and L2 of the lens barrel 2. While the positions of both the second liquid lens 62 and the second liquid lens 62 are fixed, their refractive indexes are changed to change the magnification of the finder optical system. As a result, a complicated interlocking mechanism that mechanically transmits zooming of the zoom lenses L1 and L2 to the optical system of the finder 6 and a zooming mechanism that mechanically drives the lens of the finder 6 are not required. Zooming of the zoom lenses L1 and L2 and zooming of the viewfinder 6 can be linked.

(2) The gear portion 221 provided on the cam barrel 22 for driving the zoom lenses L1 and L2 is engaged with the first gear 914 and the second gear 924, and the kinetic energy due to the driving of the gear portion 221 by zooming is finder zoom mechanism 9 To communicate. Accordingly, zooming of the zoom lenses L1 and L2 and zooming of the viewfinder 6 are linked with a simple configuration, which can contribute to downsizing.

(3) In conjunction with the zoom-up operation of the zoom lenses L 1 and L 2, the refractive index changes as the internal pressures of the first liquid lens 61 and the second liquid lens 62 increase or decrease in contradiction, and the finder 6 changes. The doubling ratio was changed. Therefore, since smooth zooming can be performed without using a mechanism for mechanically driving the lens of the finder 6, the occurrence of mechanical malfunction is eliminated, and image distortion and image skipping are eliminated, and the zoom lenses L 1, L 2 and the like. The zooming of the finder 6 can be reliably linked.

(4) The finder zoom mechanism 9 includes cylinders 911 and 921 and pistons 912 and 922. Accordingly, since the zooming of the lens barrel 2 and the finder 6 is linked with a simple configuration, the finder zoom mechanism 9 can be reduced in size.

(5) The first liquid lens 61 and the second liquid lens 62 and the finder zoom mechanism 9 are connected by flexible conduits 101 and 102. Accordingly, the degree of freedom of the position of the finder 6 is increased with respect to the arrangement of the lens barrel 2 and the finder zoom mechanism 9, and the degree of freedom of design of the camera body 1 can be improved.

The digital camera according to the embodiment described above can be modified as follows.
(1) Instead of the first liquid lens 61 and the second liquid lens 62 whose refractive index changes due to a change in internal pressure, an electric liquid lens whose refractive index changes according to the applied voltage may be used. In these electric liquid lenses, the boundary surface formed by two kinds of liquids with different properties enclosed in the inside changes according to the voltage value applied from the power source, and the refractive index changes. In this case, the CPU 14 may control the voltage value applied to each of the electric liquid lenses in accordance with the zoom-up signal or the zoom-down signal output by operating the zoom-up button 7 or the zoom-down button 8.

(2) Instead of using the right screw as the feed screw 923, an idle gear is provided between the gear portion 221 and the second gear 924, the left screw is used as the feed screw 923, and the piston is rotated along with the rotation of the cam cylinder 22. 912 and piston 922 may be driven in opposite directions.

  In addition, the present invention is not limited to the above-described embodiment as long as the characteristics of the present invention are not impaired, and other forms conceivable within the scope of the technical idea of the present invention are also within the scope of the present invention. included.

1 is an external view of a digital camera according to an embodiment of the present invention. It is a block diagram explaining the circuit structure of the digital camera by embodiment. It is sectional drawing in the imaging position of the digital camera of embodiment. It is a figure explaining the optical system of a finder. It is a figure explaining the structure around a liquid lens.

Explanation of symbols

2 Lens barrel 6 Viewfinder 9 Viewfinder zoom mechanism 61 First liquid lens 62 Second liquid lens 91 First zoom mechanism 92 Second zoom mechanism 222 Gear portions 911, 921 Cylinders 912, 922 Piston 914 First gear 924 Second gear L1 1st group lens L2 2nd group lens

Claims (5)

A photographic lens for guiding subject light to the image sensor;
Zoom means for changing the magnification of the taking lens;
An optical viewfinder having a liquid lens in the optical system;
A camera comprising: a finder zoom unit that changes a refractive index of the liquid lens in conjunction with a change in magnification of the photographing lens by the zoom unit, and changes a magnification of the optical finder. The camera of claim 1,
The camera, wherein the liquid lens is fixed at a predetermined position in the optical viewfinder. The camera according to claim 1 or 2,
The camera according to claim 1, wherein the finder zoom unit changes a refractive index of the liquid lens by using kinetic energy generated when the photographic lens is moved by the zoom unit. The camera according to any one of claims 1 to 3,
The optical viewfinder has two groups of the liquid lenses,
The camera, wherein the finder zoom means increases or decreases the internal pressure of each of the liquid lenses in a reciprocal manner. The camera according to any one of claims 1 to 4,
The finder zoom means includes a piston and a cylinder,
The camera, wherein the cylinder drives the inside of the cylinder in conjunction with the movement of the photographing lens.

Images