JP2022131939A - camera - Google Patents

Abstract

To provide a camera that is equipped with a moving mechanism for making a lens assembly difficult to tilt with respect to an optical axis and can exhibit stable imaging characteristics.SOLUTION: A camera 100 includes a cylinder 300 and a lens unit 420 with a telecentric structure. The camera further includes: a lens assembly 400 disposed within the cylinder 300; an imaging element 600 that receives light entering through the lens unit 420; and a moving mechanism 500 that moves the lens assembly 400 in an optical axis direction LL within the cylinder 300 by applying a force F in the optical axis direction LL to the lens assembly 400 from an image formation side in the optical axis direction LL.SELECTED DRAWING: Figure 2

Description

The present invention relates to cameras.

For example, the camera described in Patent Document 1 includes a lens unit, an image sensor provided behind the lens unit, and a separation distance between the lens unit and the image sensor by moving the lens unit in the optical axis direction. and a moving mechanism. The moving mechanism also has a cam plate connected to the side wall of the lens unit, and an extension coil spring that biases the cam plate rearward. Therefore, in the natural state, the lens unit is urged toward the imaging element by the restoring force of the tension coil spring. to move the lens unit forward.

JP 2005-018017 A

However, in the camera disclosed in Patent Document 1, since the cam plate is connected to the side wall of the lens unit, when the cam plate is moved forward, a force that is inclined with respect to the optical axis is applied to the lens unit. The unit tilts with respect to the optical axis. Therefore, there is a problem that stable imaging characteristics cannot be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a camera capable of exhibiting stable imaging characteristics by providing a movement mechanism in which the lens unit is less likely to tilt with respect to the optical axis. and

Such objects are achieved by the present invention of the following (1) to (10).
(1) a cylinder;
a lens assembly having a lens unit with a telecentric structure and disposed within the cylinder;
an imaging device that receives light entering from the lens unit;
a moving mechanism for moving the lens assembly in the optical axis direction within the cylinder by applying a force in the optical axis direction to the lens assembly from the imaging side in the optical axis direction. camera to do.

(2) the moving mechanism includes a rod positioned on the imaging side of the lens assembly in the optical axis direction and connected to the base end of the lens assembly;
a feeding device for feeding the rod to the light receiving side in the optical axis direction;
The camera according to (1) above, further comprising a biasing member that biases the rod toward the imaging side in the optical axis direction.

(3) the lens assembly has a sleeve positioned on the imaging side of the lens unit in the optical axis direction and connected to the lens unit;
The camera according to (2) above, wherein the rod is connected to the proximal end of the sleeve.

(4) The camera according to (2) or (3) above, wherein the rod is rod-shaped and extends in the optical axis direction.

(5) Planar view from the optical axis direction,
A camera according to any one of (2) to (4) above, wherein the rod overlaps the lens assembly.

(6) The camera according to any one of (2) to (5) above, wherein the moving mechanism has a rod guide that guides the rod in the optical axis direction.

(7) The camera according to any one of (2) to (6) above, wherein the biasing member is a compression coil spring and is arranged coaxially with the rod.

(8) The camera according to (7) above, wherein the compression coil spring has a conical shape whose diameter gradually decreases from the light receiving side in the optical axis direction toward the imaging side in the optical axis direction.

(9) The feeding device includes a presser that presses from the imaging side of the rod in the optical axis direction;
A camera according to any one of the above (2) to (8), further comprising an operating section for displacing the pressing element.

(10) The camera according to (9) above, wherein the moving axis of the pressing element is inclined with respect to the optical axis.

In the camera of the present invention, the lens assembly is moved in the optical axis direction within the cylinder by applying a force in the optical axis direction to the lens assembly from the rear side. Therefore, it becomes difficult to apply a force tilting the lens assembly with respect to the optical axis, and the lens assembly is less likely to tilt with respect to the optical axis. Such a camera can exhibit stable imaging characteristics.

1 is a front perspective view of a camera according to a preferred embodiment of the present invention; FIG. 2 is a cross-sectional view of the camera shown in FIG. 1; FIG. 2 is a rear perspective view of the camera shown in FIG. 1; FIG. It is an exploded perspective view showing a moving mechanism. It is a cross-sectional perspective view which shows the modification of a feeder. 1. It is the perspective view which looked at the 1st modification of the camera shown in FIG. 1 from the front. 7 is a cross-sectional view of the camera shown in FIG. 6; FIG. 2 is a front perspective view of a second modified example of the camera shown in FIG. 1; FIG. FIG. 9 is a cross-sectional view of the camera shown in FIG. 8;

BEST MODE FOR CARRYING OUT THE INVENTION A camera of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a front perspective view of a camera according to a preferred embodiment of the present invention. FIG. 2 is a cross-sectional view of the camera shown in FIG. 3 is a rear perspective view of the camera shown in FIG. 1. FIG. FIG. 4 is an exploded perspective view showing a moving mechanism. FIG. 5 is a cross-sectional perspective view showing a modification of the feeding device. FIG. 6 is a front perspective view of the first modification of the camera shown in FIG. 7 is a cross-sectional view of the camera shown in FIG. 6. FIG. FIG. 8 is a front perspective view of a second modification of the camera shown in FIG. 9 is a cross-sectional view of the camera shown in FIG. 8. FIG. In the following, for convenience of explanation, the left side in FIGS. 1 and 2, that is, the light receiving side in the optical axis direction LL, is defined as the front (tip), and the right side, that is, the image formation side in the optical axis direction LL is defined as the rear (base end). .

A camera 100 shown in FIG. 1 is a camera for FA (factory automation). Typically, the camera 100 is attached to an arm or the like of an FA robot that assembles, processes, inspects, etc. parts, and is used to detect the shape and position of parts, the relative relationship between the parts and the arm of the robot, and the like. Photograph the parts to obtain. However, the application of the camera 100 is not limited to this.

As shown in FIG. 2, the camera 100 includes a casing 200, a cylinder 300 mounted in front of the casing 200, a lens assembly 400 disposed within the cylinder 300, and the lens assembly 400 within the cylinder 300 along the optical axis L. and a receptacle group 800 for connection with an external device (not shown). The camera 100 also includes an imaging element 600 that receives light entering from the lens assembly 400, a first circuit board 710 that supports the imaging element 600, and a second circuit board that is electrically connected to the first circuit board 710. 720 and . The imaging device 600 , first circuit board 710 and second circuit board 720 are each housed in the casing 200 . In addition, below, the direction along the optical axis L, ie, the direction parallel to the optical axis L, is also called "optical axis direction LL" for convenience of explanation.

In the camera 100, the separation distance D between the lens assembly 400 and the imaging element 600 can be changed and adjusted by moving the lens assembly 400 in the optical axis direction LL using the moving mechanism 500. FIG. Therefore, focus adjustment (focusing) becomes possible by adjusting the separation distance D according to the shooting distance (distance to the subject). In particular, as will be described later, the moving mechanism 500 applies a force F in the optical axis direction LL to the lens assembly 400 from behind. Therefore, displacement of the lens assembly 400 in directions other than the optical axis direction LL is suppressed, and eccentricity or inclination of the lens assembly 400 with respect to the optical axis L can be suppressed. Therefore, the camera 100 can exhibit stable imaging characteristics and obtain high-quality images.

Below, each part constituting the camera 100 will be described in detail in order.
<Cylinder 300>
First, the cylinder 300 will be explained. As shown in FIG. 2, cylinder 300 has a cylindrical shape. Further, the cylinder 300 has a lens barrel accommodating portion 350 in which the lens barrel 430 is accommodated, and a sleeve accommodating portion 360 positioned behind the lens barrel accommodating portion 350 and in which the sleeve 410 is accommodated. Further, the lens barrel accommodating portion 350 has a larger diameter than the sleeve accommodating portion 360, and a stepped surface 370 facing forward is formed at the boundary between them. The step surface 370 is a flat surface orthogonal to the optical axis L. As shown in FIG. The step surface 370 abuts against the lens barrel 430 and functions as a stopper that restricts further rearward movement of the lens barrel 430 .

Further, the cylinder 300 has a small outer diameter portion 310 and a large outer diameter portion 330 having an outer diameter larger than that of the small outer diameter portion 310 . These are integrally formed so as to line up in the optical axis direction LL in order of the small outer diameter portion 310 and the large outer diameter portion 330 from the front. Further, the cylinder 300 has a step surface 340 formed at the boundary between the small outer diameter portion 310 and the large outer diameter portion 330 and facing forward. The step surface 340 is a flat surface perpendicular to the optical axis L. As shown in FIG.

A thread groove 311 is formed on the outer periphery of the small outer diameter portion 310 . D-cut surfaces 331, which are flat surfaces obtained by notching a portion of the cylindrical outer peripheral surface, are formed on the upper and lower portions of the outer peripheral surface of the large outer diameter portion 330, respectively. A pair of D-cut surfaces 331 are formed on the upper side and the lower side of the large outer diameter portion 330 at regular intervals (180° intervals) and face each other. However, the configuration of the cylinder 300 is not particularly limited, and for example, the screw groove 311 and the D-cut surface 331 may be omitted.

The cylinder 300 having such a configuration is made of a metal material such as aluminum or stainless steel. Thereby, the cylinder 300 having sufficient rigidity can be obtained, and the lens assembly 400 housed inside can be stably held. Moreover, the cylinder 300 is formed by NC (Numerical Control) lathe processing, for example. By using NC lathe processing, the cylinder 300 can be formed with excellent dimensional accuracy. Therefore, rattling of the lens assembly 400 within the cylinder 300 can be suppressed, and the lens assembly 400 can be smoothly moved within the cylinder 300 . However, the material and forming method of the cylinder 300 are not particularly limited.
The cylinder 300 has been described above.

<Casing 200>
Next, casing 200 will be described. As shown in FIG. 2 , casing 200 is positioned behind cylinder 300 . Further, the casing 200 has a substantially rectangular notched shape at the rear upper portion. Therefore, the casing 200 has a high-back portion 201 that holds the cylinder 300 and a low-back portion 202 located behind the high-back portion 201 and shorter than the high-back portion 201 . A feeding device 550, which will be described later, protrudes from the rear surface 201B of the high-back portion 201. As shown in FIG. Further, a receptacle group 800 is provided on the rear surface 202B of the low back portion 202. As shown in FIG.

In this way, by providing the receptacle group 800 on the rear surface 202B of the low-back portion 202, that is, on the rearmost portion of the casing 200, it becomes easier to secure a space around the receptacle group 800 and to easily approach the receptacle group 800. becomes. Further, although not shown, when the cable is connected to the receptacle group 800, the cable extends backward, so that the entire camera 100 including the cable spreads in the direction orthogonal to the optical axis L, in other words, from the optical axis direction LL. It is possible to suppress the spread of the contour of the camera 100 in plan view. Therefore, the size of the camera 100 can be reduced.

As shown in FIGS. 2 and 3, in the present embodiment, the receptacle group 800 includes an image data output receptacle 810 for transmitting an image captured by the camera 100, and a control signal receptacle 810 for receiving a control signal. of receptacle 820 and . However, the number and functions of receptacles included in receptacle group 800 are not particularly limited.

Further, as shown in FIG. 2, the casing 200 has a base chassis 210 forming its lower portion and an upper case 220 forming its upper portion. Cylinder 300 is held by sandwiching the base end of cylinder 300 between base chassis 210 and upper case 220 . However, the configuration of casing 200 is not particularly limited.

Base chassis 210 and upper case 220 are made of a metal material such as aluminum or stainless steel. Thereby, the casing 200 having sufficient rigidity is obtained, and the cylinder 300 can be stably held. Specifically, in the present embodiment, base chassis 210 and upper case 220 are each die cast or castings. By using die casting, an inexpensive base chassis 210 and upper case 220 can be obtained. In addition, high dimensional accuracy can be obtained partially by secondary processing. However, the material and formation method of the base chassis 210 and the upper case 220 are not particularly limited.
The casing 200 has been described above.

<Lens assembly 400>
Next, the lens assembly 400 is described. As shown in FIG. 2, lens assembly 400 is coaxially disposed within cylinder 300 . Also, the lens assembly 400 can move (slid) in the optical axis direction LL with respect to the cylinder 300 . Such a lens assembly 400 has a lens unit 420 and a sleeve 410 connected to the proximal end of lens unit 420 .

The lens unit 420 has a cylindrical barrel 430 and a lens group 440 and a diaphragm 450 arranged inside the barrel 430 . The lens unit 420 of this embodiment is a lens unit with a telecentric structure. A telecentric structure refers to a structure in which the principal ray is parallel to the optical axis L. The telecentric structure is suitable for FA because it has characteristics suitable for measurement applications in that the optical magnification does not change even if the distance to the subject changes. In particular, the lens unit 420 of this embodiment has a bilateral telecentric structure in which both the object side and the image side are telecentric. However, the lens unit 420 is not limited to this. For example, it may be an object-side telecentric structure in which only the object side is telecentric, or an image-side telecentric structure in which only the image side is telecentric. good.

The lens barrel 430 has a pair of ring-shaped flanges 431 and 432 projecting outward from the outer peripheral surface. The flange 431 is positioned at the distal end of the outer peripheral surface of the lens barrel 430 , and the flange 432 is positioned at the proximal end of the outer peripheral surface of the lens barrel 430 . The lens barrel 430 is in contact with the inner peripheral surface of the cylinder 300 at the outer peripheral surfaces of these flanges 431 and 432 . That is, the lens barrel 430 is in contact with the cylinder 300 at both ends except for the central portion. With such a configuration, the contact area between the cylinder 300 and the lens barrel 430 can be reduced while the posture of the lens barrel 430 within the cylinder 300 is stabilized. Therefore, stable movement of the lens barrel 430 within the cylinder 300 is possible. However, the configuration of the lens barrel 430 is not particularly limited.

The lens barrel 430 having such a configuration is made of, for example, a metal material such as aluminum or stainless steel. This provides the lens barrel 430 with sufficient rigidity. In particular, the lens barrel 430 of this embodiment is made of the same material as the cylinder 300 . As a result, the coefficients of linear expansion of the cylinder 300 and the lens barrel 430 are equalized, and it is possible to prevent backlash between the cylinder 300 and the lens barrel 430 due to temperature rise and, conversely, slow movement of the lens barrel 430. can be effectively suppressed. Also, the lens barrel 430 is formed by, for example, NC lathe processing. By using NC lathe processing, the lens barrel 430 can be formed with excellent dimensional accuracy. However, the material and formation method of the lens barrel 430 are not particularly limited.

Thus, in this embodiment, both the cylinder 300 and the lens barrel 430 are formed by NC lathe processing. Therefore, these clearances can be managed with high precision, and the lens barrel 430 can be assembled to the cylinder 300 with high precision. Therefore, the lens unit 420 can be smoothly moved within the cylinder 300, and eccentricity and tilting of the lens unit 420 with respect to the optical axis L within the cylinder 300 can be suppressed.

The sleeve 410 is provided behind the barrel 430 . The sleeve 410 also has a lens unit inserting portion 413 facing the front opening. A base end portion of the lens barrel 430 is inserted into the lens unit insertion portion 413 and they are screwed together. Also, the lens unit insertion portion 413 has a larger inner diameter than the rear portion thereof. Therefore, a step surface 414 facing forward is formed on the base end side of the lens unit insertion portion 413 . The step surface 414 is a flat surface perpendicular to the optical axis L and functions as a diopter stop for the lens unit 420 . Therefore, positioning of the lens unit 420 with respect to the sleeve 410 is facilitated.

It should be noted that the lens unit insertion portion 413 of the present embodiment is configured according to the C-mount standard. Therefore, the lens unit 420 can be exchanged according to the application as long as it conforms to the C-mount standard. However, the standard of the lens unit insertion portion 413 is not particularly limited, and for example, it may be configured according to the S-mount standard, or may be configured according to other standards.

The sleeve 410 having such a configuration is made of, for example, a metal material such as aluminum or stainless steel. This provides sleeve 410 with sufficient rigidity. In particular, sleeve 410 of this embodiment is made of the same material as cylinder 300 and lens barrel 430 . Thereby, the linear expansion coefficients of the cylinder 300, the lens barrel 430 and the sleeve 410 become equal. Therefore, it is possible to effectively suppress the occurrence of backlash between the cylinder 300 and the sleeve 410 due to the rise in temperature and, conversely, the movement of the sleeve 410 from slowing down. Moreover, thermal stress is less likely to be applied to the lens unit 420, and damage to the lens unit 420, fluctuations in optical characteristics, and the like can be suppressed. Also, the sleeve 410 is formed by, for example, NC lathe processing. By using NC lathe processing, the sleeve 410 can be formed with excellent dimensional accuracy. However, the material and forming method of the sleeve 410 are not particularly limited.

The lens assembly 400 has been described above. A lubricant (not shown) is provided between the outer peripheral surface of the lens assembly 400 and the inner peripheral surface of the cylinder 300 to reduce their sliding resistance. Therefore, the lens assembly 400 can be smoothly moved within the cylinder 300 . Although the lubricant is not particularly limited, various solid lubricants such as molybdenum-based, graphite-based, and fluorine-based lubricants are used in this embodiment.

<Image sensor 600>
Next, the imaging device 600 will be described. As shown in FIG. 2, the imaging device 600 is provided behind the lens assembly 400 and has a light receiving surface perpendicular to the optical axis L. As shown in FIG. The imaging device 600 receives light entering from the lens assembly 400 . The imaging element 600 is not particularly limited, and a CCD image sensor, a CMOS image sensor, or the like can be used. Various specifications such as the device size (dimensions) and resolution of the imaging device 600 can be appropriately set according to the specifications required for the camera 100 .
The imaging element 600 has been described above.

<First circuit board 710>
Next, the first circuit board 710 is described. As shown in FIG. 2, the first circuit board 710 is provided behind the imaging element 600 and arranged in a posture perpendicular to the optical axis L. As shown in FIG. Also, the first circuit board 710 supports the imaging device 600 . That is, the first circuit board 710 is a sensor board on which the imaging device 600 is mounted. The first circuit board 710 is screwed to the base end surface of the cylinder 300 with screws B1. Here, as described above, since the cylinder 300 is formed by NC lathe processing, the formation accuracy of the base end surface is high, and the perpendicularity to the optical axis L can be controlled with high accuracy. Therefore, by fixing the first circuit board 710 to the base end surface of the cylinder 300, the imaging element 600 can be positioned with respect to the optical axis L with high accuracy. However, the method of fixing the first circuit board 710 and the object to be fixed are not particularly limited.
The first circuit board 710 has been described above.

<Second circuit board 720>
Next, the second circuit board 720 is described. As shown in FIG. 2, the second circuit board 720 is provided behind the first circuit board 710 in the casing 200 and is arranged parallel to the optical axis L. As shown in FIG. The second circuit board 720 is screwed to the base chassis 210 with screws B2. However, the method of fixing the second circuit board 720 and the object to be fixed are not particularly limited. Also, for example, the second circuit board 720 may be omitted and the function thereof may be provided to the first circuit board 710 .

An IC chip 730 , which is a circuit element for controlling driving of the camera 100 , is mounted on the second circuit board 720 . IC chip 730 is electrically connected to first circuit board 710 and receptacle group 800 . IC chip 730 controls each part of camera 100 based on control signals received via receptacle 820 . The IC chip 730 also generates image data based on the photoelectric conversion signal output from the imaging device 600 and outputs the generated image data from the receptacle 810 .
The second circuit board 720 has been described above.

<Moving mechanism 500>
Next, the moving mechanism 500 is described. The moving mechanism 500 is a mechanism for moving the lens assembly 400 in the optical axis direction LL to change and adjust the separation distance D between the lens assembly 400 and the imaging device 600 . As shown in FIGS. 2 and 4, the moving mechanism 500 includes a rod 510 connected to the lens assembly 400, a rod head 520 connected to the proximal end of the rod 510, and guiding the rod 510 in the optical axis direction LL. A rod guide 530, a compression coil spring 540 as a biasing member that biases the rod 510 rearward, and a feeding device 550 that feeds the rod 510 forward against the force of the compression coil spring 540. have.

Rod 510 is provided behind lens assembly 400 within casing 200 . Moreover, the rod 510 is rod-shaped and extends in the optical axis direction LL. Further, the rod 510 overlaps the sleeve 410 in plan view from the optical axis direction LL. Also, the rod 510 is connected at its distal end to the proximal end of the sleeve 410 . Specifically, the tip of the rod 510 is screwed into a screw hole 415 formed in the base end surface of the sleeve 410 . Therefore, when the rod 510 moves forward, the rod 510 pushes the lens assembly 400 forward. Conversely, when the rod 510 moves rearward, the rod 510 pulls the lens assembly 400 backward.

With such a shape and arrangement of the rod 510, the spread of the camera 100 in the direction orthogonal to the optical axis L, in other words, the spread of the contour of the camera 100 in plan view from the optical axis direction LL can be suppressed. Therefore, the size of the camera 100 can be reduced. Also, by connecting the rod 510 to the sleeve 410, the lens unit 420 is not directly pressed by the rod 510, so the load applied to the lens unit 420 can be reduced.

The rod 510 having such a configuration is made of, for example, a metal material such as aluminum or stainless steel. Thereby, the rod 510 having sufficient rigidity can be obtained, and the pressing force from the feeding device 550 can be efficiently transmitted to the lens assembly 400 . Therefore, the lens assembly 400 can be moved smoothly.

Rod head 520 is connected to the proximal end of rod 510 . Moreover, the rod head 520 has a head portion 521 having a diameter larger than that of the rod 510 . A front surface 521a and a rear surface 521b of the head 521 are flat surfaces perpendicular to the optical axis L, respectively. The front surface 521a is a contact surface with which the compression coil spring 540 abuts, and the rear surface 521b is a contact surface with which the feeding device 550 abuts.

The rod head 520 having such a configuration is made of various resin materials such as PEEK (polyetheretherketone). Since PEEK exhibits excellent mechanical strength and anti-friction properties, it is a suitable material for contact with the compression coil spring 540 and the feeding device 550 . However, it is not limited to this, and may be made of a metal material such as aluminum or stainless steel. This allows the rod head 520 to be manufactured at a lower cost than PEEK.

Rod guide 530 is provided behind first circuit board 710 in casing 200 . The rod guide 530, together with the first circuit board 710, is screwed to the base end surface of the cylinder 300 with screws B1. The rod guide 530 has a base 531 supported by the first circuit board 710 and a truncated conical projection 532 projecting rearward from the base 531 .

The base portion 531 is a plate-like portion whose thickness direction is the optical axis direction LL. A rear surface of the base portion 531 is a contact surface with which the compression coil spring 540 contacts. The base 531 is provided with a flange 533 projecting rearward from its outer edge. A flange 533 surrounds the outer circumference of the compression coil spring 540 and positions the compression coil spring 540 with respect to the rod guide 530 .

A through hole H is formed between the top surface of the protruding portion 532 and the front surface of the first circuit board 710 and extends in the optical axis direction LL. A rod 510 is inserted through the through hole H. As shown in FIG. Therefore, the rod 510 is allowed to move in the optical axis direction LL, and movement in other directions, especially rotation around the optical axis L, is restricted. Thereby, the operability of the rod 510 is improved, and the lens assembly 400 can be smoothly moved in the optical axis direction LL. In particular, by adopting a configuration in which the protruding portion 532 protrudes rearward as in the present embodiment, the through hole H can be formed long in the optical axis direction LL. Therefore, the above effect becomes more remarkable, and the operability of rod 510 is further improved.

Lubricant (not shown) is provided between the inner surface of the through hole H and the rod 510 to reduce sliding resistance therebetween. Therefore, the rod 510 can be smoothly moved with respect to the through hole H. Although the lubricant is not particularly limited, various solid lubricants such as molybdenum-based, graphite-based, and fluorine-based lubricants are used in this embodiment.

Compression coil spring 540 is provided around rod 510 . In other words, the rod 510 is passed through the compression coil spring 540 . Also, the compression coil spring 540 is arranged in a contracted (compressed) state between the base portion 531 of the rod guide 530 and the rod head 520 . Therefore, the restoring force of the compression coil spring 540 urges the rod 510 rearward. As described above, the compression coil spring 540 is positioned by the rod guide 530 and its central axis coincides with the central axis J1 of the rod 510. As shown in FIG. That is, the compression coil spring 540 is arranged coaxially with the rod 510 . Therefore, it becomes difficult for the compression coil spring 540 to apply a force in a direction inclined with respect to the optical axis L to the rod 510 . Therefore, the rod 510 can be smoothly moved in the optical axis direction LL.

Also, the compression coil spring 540 has a conical shape whose diameter gradually decreases from the front to the rear. That is, the compression coil spring 540 is a conical coil spring. Therefore, it becomes easier to concentrate the force toward the central axis J1 of the rod 510 . Therefore, even with this configuration, it is difficult for the compression coil spring 540 to apply a force in a direction inclined with respect to the optical axis L to the rod 510 . Therefore, the rod 510 can be smoothly moved in the optical axis direction LL. However, the compression coil spring 540 is not particularly limited, and for example, a cylindrical coil spring, a barrel-shaped coil spring, a drum-shaped coil spring, or the like may be used. Also, instead of the compression coil spring 540, an extension coil spring, a leaf spring, or the like may be used as the biasing member. Alternatively, an extension coil spring may be used to bias the rod 510 rearward.

The reason why the protruding portion 532 of the rod guide 530 is shaped like a truncated cone is to match the shape of the compression coil spring 540 . In this way, by forming both the protrusion 532 and the compression coil spring 540 into truncated conical shapes, it is possible to effectively suppress contact between them when the compression coil spring 540 is contracted, and the rod 510 is moved in the optical axis direction LL. can be moved smoothly. Particularly in this embodiment, the taper angle of the protruding portion 532 is equal to the taper angle of the compression coil spring 540 when the lens assembly 400 is positioned at the forwardmost position. Thereby, the above-mentioned effect becomes more remarkable.

The feeding device 550 presses the rod 510 forward against the force of the compression coil spring 540 . In this embodiment, as the feeding device 550, a micrometer head 550A is used. The micrometer head 550A has a known structure, and has a spindle 551 as a pressing element, a sleeve 552, a thimble 553 as an operation part, and a ratchet stop 554. By using the micrometer head 550A, the separation distance D can be adjusted more finely and accurately. In addition, since the ratchet stop 554 is not used in this embodiment, it may be omitted.

Micrometer head 550A is fixed to upper case 220 of casing 200 at sleeve 552 . In this embodiment, the micrometer head 550A is inserted through an insertion hole 221 formed in the rear surface 201B of the upper case 220, and is fixed and positioned with respect to the casing 200 by a set screw B3.

When the micrometer head 550</b>A is fixed to the casing 200 , the spindle 551 is positioned inside the casing 200 and its tip surface is in contact with the rear surface 521 b of the rod head 520 . A tip surface of the spindle 551 has a spherical shape. Therefore, for example, as compared with the case of flat surfaces, wear of the spindle 551 and rod head 520 and errors due to inclination of the micrometer head 550A can be suppressed. On the other hand, thimble 553 and ratchet stop 554 protrude outside casing 200 and are exposed. The portion that protrudes outside the casing 200 is located above the low-back portion 202 and in the notched portion.

When the thimble 553 is rotated forward, the spindle 551 advances, the rod 510 pushed by the spindle 551 moves forward against the biasing force of the compression coil spring 540, and the lens assembly 400 pushed by the rod 510 moves forward. Moving. This increases the separation distance D between the lens assembly 400 and the imaging device 600 . Conversely, when the thimble 553 is reversely rotated, the spindle 551 is retracted, the rod 510 is moved rearward by the biasing force of the compression coil spring 540, and the lens assembly 400 pulled by the rod 510 is moved rearward. As a result, the separation distance D between the lens assembly 400 and the imaging device 600 is reduced. By operating the micrometer head 550A in this manner, focus adjustment (focusing) of the camera 100 becomes possible. Therefore, the shooting distance and resolution (physical resolution) of camera 100 can be changed without replacing lens unit 420 .

In this way, according to the micrometer head 550A, the separation distance D can be changed simply by rotating the thimble 553, so that the camera 100 is less likely to be subjected to excessive stress due to the user's operation. Therefore, breakage of each component constituting the camera 100 is suppressed. Further, since the micrometer head 550A is provided with a scale (not shown) that indicates the amount of extension of the spindle 551, it is also possible to read the separation distance D from the scale.

Note that the method of focus adjustment is not particularly limited. For example, an image captured by the camera 100 may be displayed on a monitor or the like, and the operator may adjust the focus by operating the micrometer head 550A while viewing the image. Alternatively, software that automatically performs focus adjustment (focusing) so as to maximize the physical resolution may be used.

The axis of movement of the spindle 551, that is, the central axis J2 of the spindle 551 is inclined with respect to the optical axis L (=the central axis J1) so that the rear side is positioned upward. By inclining the central axis J2 with respect to the optical axis L in this manner, interference between the micrometer head 550A and the casing 200 can be prevented, and the micrometer head 550A can be easily arranged. Moreover, it becomes easy to secure a space around the thimble 553, and the thimble 553 becomes easy to operate. Further, compared to the case where the central axis J2 is parallel to the optical axis L, the amount of displacement of the lens assembly 400 with respect to the amount of rotation of the thimble 553 can be reduced. Therefore, the separation distance D can be adjusted more finely.

Incidentally, by inclining the central axis J2 with respect to the optical axis L, an error occurs between the feed amount of the thimble 553 displayed on the micrometer head 550A and the actual displacement amount of the lens assembly 400, but as described above. As described above, since the display of the micrometer head 550A is not used during focus adjustment (focusing), there is no particular problem. The inclination angle θ of the central axis J2 with respect to the optical axis L is not particularly limited, but is preferably about 5° to 10°, more preferably about 7° to 9°. As a result, the portions of micrometer head 550A protruding from casing 200 (thimble 553 and ratchet stop 554) are prevented from excessively protruding upward from casing 200, and the above effects can be sufficiently exhibited. .

The moving mechanism 500 has been described above. According to such a moving mechanism 500, the lens assembly 400 is moved in the optical axis direction LL within the cylinder 300 by applying the force F in the optical axis direction LL to the lens assembly 400 from the rear side. Therefore, it becomes difficult for the lens assembly 400 to be subjected to an oblique force with respect to the optical axis L, and the lens assembly 400 is less likely to be decentered or tilted with respect to the optical axis L. Therefore, the camera 100 can exhibit stable imaging characteristics.

In particular, the moving mechanism 500 includes a rod 510 positioned behind the lens assembly 400 and connected to the base end of the lens assembly 400, a feeding device 550 feeding the rod 510 forward in the optical axis direction LL, and the rod 510 and a compression coil spring 540 as a biasing member that biases backward in the optical axis direction LL. Combining such parts simplifies the configuration of the moving mechanism 500 .

However, the feeding device 550 is not particularly limited as long as it can feed the rod 510 forward. For example, as shown in FIG. 5, a feed screw guide 557 fixed to the casing 200, a feed screw shaft 558 screwed into the feed screw guide 557, the tip of which abuts on the rod head 520, and the feed screw shaft 558 are moved backward. and a compression coil spring 559 that biases and restricts the rotation of the feed screw shaft 558 . With such a configuration, the rod 510 can be moved forward by forwardly rotating the feed screw shaft 558 against the biasing force of the compression coil spring 559 . Conversely, rotating the lead screw shaft 558 in the opposite direction causes the rod 510 to move rearward. In FIG. 5, illustration of thread grooves formed on the inner peripheral surface of the feed screw guide 557 and the outer peripheral surface of the feed screw shaft 558 is omitted.

Although the camera of the present invention has been described above based on the illustrated embodiments, the present invention is not limited to this, and the configuration of each section can be replaced with any configuration having similar functions. can be done. Also, other optional components may be added to the present invention.

For example, the configurations shown in FIGS. 6 and 7 and the configurations shown in FIGS. 8 and 9 may be used. In both of these two configurations, the tip of lens unit 420 protrudes from the front opening of cylinder 300 . Such a configuration is effective when the diameter of the distal end of the lens unit 420 is larger than that of the proximal end. This is because the diameter of the cylinder 300 can be designed to match the diameter of the base end portion, so that the diameter of the cylinder 300 can be reduced. Therefore, the size of the camera 100 can be reduced. In addition, since the cylinder 300 is shortened, the manufacturing cost can be reduced, and the cost of the camera 100 can be reduced. Further, since the lens unit 420 protrudes from the cylinder 300, the lens unit 420 can be easily removed from the cylinder 300, and the lens unit 420 can be easily replaced.

In particular, in the configuration shown in FIGS. 6 and 7, the screw groove 311, the D-cut surface 331 and the stepped surface 340 are removed from the outer circumference of the cylinder 300, so that the outer circumference of the cylinder 300 has a clean circumferential surface. Therefore, the formation of the cylinder 300 is facilitated, and the cost of the camera 100 can be reduced accordingly. 8 and 9, a pair of D-cut surfaces 312 are formed in the small outer diameter portion 310 instead of the thread groove 311. As shown in FIG.

DESCRIPTION OF SYMBOLS 100... Camera 200... Casing 201... High back part 201B... Rear surface 202... Low back part 202B... Rear surface 210... Base chassis 220... Upper case 221... Insertion hole 300... Cylinder 310... Small outer diameter part 311... Screw groove 312... D cut surface 330 Large outer diameter portion 331 D-cut surface 340 Stepped surface 350 Lens barrel accommodating portion 360 Sleeve accommodating portion 370 Stepped surface 400 Lens assembly 410 Sleeve 413 Lens unit insertion portion 414 Stepped surface 415 Screw Hole 420 Lens unit 430 Lens barrel 431, 432 Flange 440 Lens group 450 Diaphragm 500 Movement mechanism 510 Rod 520 Rod head 521 Head 521a Front 521b Rear 530 Rod guide 531 Base 532 Protrusion 533 Flange 540 Compression coil spring 550 Feeding device 550A Micrometer head 551 Spindle 552 Sleeve 553 Thimble 554 Ratchet stop 557 Feed screw guide 558 Feed screw shaft 559 Compression coil spring 600 Imaging device 710 First circuit board 720 Second circuit board 730 IC chip 800 Receptacle group 810, 820 Receptacle B1, B2 Screw B3 Set screw D Separation distance F Force H Through hole J1, J2 Central axis L... Optical axis LL... Optical axis direction θ... Tilt angle

Claims (10)

a cylinder;
a lens assembly having a lens unit with a telecentric structure and disposed within the cylinder;
an imaging device that receives light entering from the lens unit;
a moving mechanism for moving the lens assembly in the optical axis direction within the cylinder by applying a force in the optical axis direction to the lens assembly from the imaging side in the optical axis direction. camera to do. the moving mechanism includes a rod positioned on the imaging side of the lens assembly in the optical axis direction and connected to a base end portion of the lens assembly;
a feeding device for feeding the rod to the light receiving side in the optical axis direction;
2. The camera according to claim 1, further comprising a biasing member that biases the rod toward the imaging side in the optical axis direction. The lens assembly has a sleeve located on the imaging side of the lens unit in the optical axis direction and connected to the lens unit,
3. A camera according to claim 2, wherein said rod is connected to the proximal end of said sleeve. 4. A camera according to claim 2, wherein said rod is rod-shaped and extends in said optical axis direction. In a plan view from the optical axis direction,
5. A camera as claimed in any one of claims 2 to 4, wherein the rod overlaps the lens assembly. 6. A camera according to claim 2, wherein said moving mechanism has a rod guide that guides said rod in said optical axis direction. 7. A camera according to any one of claims 2 to 6, wherein said biasing member is a compression coil spring and arranged coaxially with said rod. 8. The camera according to claim 7, wherein the compression coil spring has a conical shape whose diameter gradually decreases from the light receiving side in the optical axis direction toward the imaging side in the optical axis direction. The feeding device includes a presser that presses the rod from the imaging side in the optical axis direction;
9. The camera according to any one of claims 2 to 8, further comprising an operation section for displacing the pressing element. 10. A camera according to claim 9, wherein the moving axis of said pressing element is inclined with respect to the optical axis.

Images