JP2020042119A - Lens barrel having dust-proof drip-proof function - Google Patents

Abstract

To provide a lens barrel that has a dust-proof drip-proof function, and can exert an optical performance by the adjustment in an alignment process and adjustment process.SOLUTION: A lens barrel includes: a lens mirror room for holding a lens; an adjustment cylinder used for optical adjustment of the lens mirror room; a front ring for fixing the lens mirror room; and a dust-proof drip-proof ring. The adjustment cylinder forms a lead cam, the center line of the lead cam forms an acute angle with respect to the line perpendicular to the optical axis of the lens, and the adjustment cylinder is located outside the radial direction of the lens with respect to the lens mirror room engaging with the lead cam. The dust-proof drip-proof ring is in contact with the lens mirror room in the radial direction, and is grasped between the front ring and the adjustment cylinder in the thrust direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens barrel having a dust-proof and drip-proof function.

  In recent years, interchangeable lenses and camera bodies often have a dust-proof and drip-proof function for preventing water and dust from entering the inside from the outside. As a specific method of realizing the dust-proof and drip-proof function, the function is realized by arranging an annular cushioning material described in Patent Document 1 inside the lens barrel in order to prevent raindrops or the like from entering through a gap. It is known to

  Along with the dust-proof and drip-proof function, the lens barrel is required to have high optical performance. In such a lens barrel, sufficient optical performance cannot be obtained by assembling the lens barrel simply by designing the lens chamber holding the optical element so as to match the lens barrel. This is because the lens barrel has a plurality of lens chambers inside, so that the positional relationship between the lens chambers is shifted. This is because such a shift adversely affects the optical performance of the lens barrel.

  Therefore, in recent years, a centering process is used to suppress the above-described displacement inside the lens barrel and a decrease in optical performance caused by a manufacturing error.

  In the alignment process, the lens barrel is attached to an alignment tool such as an MTF measuring instrument, and the position of the lens chamber held in the lens barrel is adjusted while observing the lens performance. In the alignment process, the position of the lens chamber was adjusted, and when the lens chamber reached the optimal position for exhibiting the lens performance, adhesive was applied to the joint between the lens barrel and the lens chamber. And fix it. Through these alignment steps, the lens barrel can exhibit its original optical performance.

JP 2006-201250 A

  In the lens barrel described in Patent Document 1, when the first lens group mirror chamber is moved in the thrust direction during an adjustment step such as a centering step or a lens gap adjustment, the distance between the first lens group mirror chamber and the holding ring changes. Therefore, the amount of crushing of the cushioning material and the amount of bulging to the inner and outer diameters are not constant.

  Even when the distance between the first lens group mirror chamber and the holding ring is maximum, that is, the amount of crushing of the cushioning material is minimum, it is necessary to contact the first lens group mirror chamber and the holding ring in order to maintain the dust-proof and drip-proof function. Therefore, the cushioning material needs a certain thickness in the thrust direction and has a problem that the volume is large.

  Furthermore, as the distance between the first lens group mirror chamber and the holding ring becomes smaller, the repulsive force with respect to the crushing amount of the cushioning material becomes larger, so that there is a problem that the first lens mirror chamber may be displaced.

  The present invention has been made in view of such a situation, and has a dust-proof and drip-proof function, and a lens barrel that can exhibit optical performance by being adjusted in a centering process and an adjustment process. The purpose is to provide.

  According to a first aspect of the present invention, there is provided a lens mirror chamber for holding a lens, an adjusting cylinder used for optical adjustment of the lens mirror chamber, a front ring for fixing the lens mirror chamber, and dustproofing. In a lens barrel having a drip-proof ring, the adjusting barrel forms a lead cam, a center line of the lead cam forms an acute angle with a line perpendicular to an optical axis of the lens, and the lens mirror engages with the lead cam. The dust-proof and drip-proof ring is located radially outward of the lens with respect to the chamber, is in contact with the lens mirror chamber in the radial direction, and is sandwiched between the front ring and the adjustment barrel in the thrust direction. Lens barrel.

  According to a second aspect of the present invention, there is provided a lens barrel according to the first aspect, wherein the lens barrel has a pressing ring outward in the radial direction with respect to the lens mirror chamber. The dustproof and drip-proof ring is in contact with the holding ring in the radial direction, and is sandwiched between the front ring and the adjustment barrel in a thrust direction.

  According to the present invention, it is possible to provide a lens barrel having a dust-proof and drip-proof function and capable of exhibiting optical performance by being adjusted in a centering step and an adjusting step.

Sectional view of lens barrel 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the lens barrel 1 according to the embodiment of the present invention after alignment adjustment. 1. Enlarged view of the engagement relationship between the first lens group mirror chamber 101, the adjustment barrel 102, and the fixed barrel 103 shown in FIG. Lens barrel 1 and sectional view according to another embodiment of the present invention

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. Note that the present invention is not limited by the embodiment.

  FIG. 1 is a cross-sectional view around the first lens group of the lens barrel of the present embodiment. In addition, each drawing is simplified for simplifying the description of the present invention. Unless otherwise specified, in the drawings except for FIG. 3, the left side is the subject side and the right side is the image side, and the up-down direction is the radial direction and the left-right direction is the thrust direction. In the center diagram of FIG. 3, the lower left side is the object side, and the upper right side is the image side.

  In this embodiment, 1 is a lens barrel, 100 is a first lens, 101 is a first lens group mirror chamber, 102 is an adjusting barrel, 103 is a fixed barrel, 104 is a buffer, 105 is a front ring, and 106 is a front rubber. , 107 is a decorative ring, 108 is a presser ring, and 110 is a centering fixed group.

  The lens barrel 1 is detachable from a camera body (not shown), and the mount of the lens barrel 1 and the mount of the camera body are connected by a bayonet mechanism or the like.

  The first lens 100 is a lens located in the first lens group of the lens barrel 1.

  The first lens group mirror room 101 is a mirror room that holds the first lens 100.

  The adjustment cylinder 102 has a lead cam cut off, and is engaged with the first lens group mirror chamber 101 by rollers. Therefore, by rotating the adjustment barrel 102, the first lens group mirror chamber 101 moves back and forth in the thrust direction along the optical axis, and the held first lens 100 also moves. By adjusting the first lens 100 to a preferable position, the lens barrel 1 exhibits preferable optical performance.

  The fixed barrel 103 engages and holds the first lens group mirror chamber 101, the adjustment barrel 102, and the lead cam with rollers.

  The first lens 100, the first lens group mirror chamber 101, and the alignment fixed group 110 move together as a unit when the alignment is performed.

  The buffer material 104 is an elastic member and is made of a water-repellent microporous member. It plays a role in preventing water and foreign substances from entering the inside of the lens barrel 1. The radial direction is sandwiched between the adjustment cylinder 102 and the front ring 105.

  The front ring 105 is an external part for attaching a filter or a hood. A front rubber 106 molded by an elastic member is fixed to a front end of the front ring 105.

  The front rubber 106 is attached to the front end of the lens barrel 1 on the subject side. This serves to protect the lens barrel 1 when the lens barrel 1 is placed upright or when the tip of the lens barrel 1 comes into contact with something.

  The makeup ring 107 has a function of cutting a light beam coming from the subject side, and hides a swage for fixing the first lens.

  The presser ring 108 has a function of cutting light rays incident from the subject side, and plays a role of fixing the first lens 100.

  The alignment fixing group 110 includes a screw for fixing the alignment group and an eccentric roller for adjusting in the alignment process.

  Here, the centering step will be described.

  The alignment process includes two main methods, shift alignment and tilt alignment. Shift alignment adjusts the position of the alignment group in the direction perpendicular to the optical axis by moving the alignment group on a plane perpendicular to the optical axis of the lens barrel 1 not shown in FIG. Specifically, the direction is the up-down direction and the front-back direction on the paper surface in FIG. The tilt alignment adjusts the inclination of the alignment group with respect to the optical axis by tilting a surface perpendicular to the optical axis from the alignment group toward the subject side or the image side.

  Apart from the alignment process, there is also an adjustment called lens interval adjustment. This lens interval adjustment is for adjusting a lens group or a lens interval in a lens group in order to adjust focusing performance, spherical aberration, and field curvature.

  FIG. 2 is a cross-sectional view of the lens barrel 1 showing a state in which the first lens 100 is moved to the most object side by tilt alignment and adjustment of a lens interval.

  When the alignment step and the lens interval adjustment are performed in the embodiment of the present application, the alignment group includes the first lens 100, the first lens group mirror chamber 101, and the alignment fixed group 110. When the components of the alignment group are adjusted, they move together in the tilt direction and the thrust direction.

  By performing any one of the alignment steps described above, the alignment group is adjusted to an appropriate position for exhibiting optical performance, and then a jig is fixed from outside the lens barrel 1 to the alignment center group 110. The alignment group is fixed by accessing and operating.

  The movement of each component when the alignment process is specifically performed will be described below.

  FIG. 3 is a bird's-eye view of the first lens group mirror room 101, the adjusting barrel 102, and the fixed barrel 103. In the figure, the eccentric rollers constituting the alignment center fixing group 110 fixed by screws in the first lens group mirror chamber 101 engage with the lead cam of the adjustment cylinder 102, and the lead cam having a width in the radial direction of the fixing cylinder 103. Engage. The roller of the adjustment barrel 102 engages with a lead cam movable around the optical axis of the fixed barrel 103. In the figure, O indicates the optical axis, A indicates the radial direction, B indicates the thrust direction, and C indicates the center line of the lead cam of the adjusting cylinder 102.

  As shown in FIG. 3, the adjusting cylinder 102 is equally cut with lead cams at three locations on the circumference. The center line of the lead cam forms an acute angle with a line perpendicular to the optical axis.

  This will be described with reference to the lower right diagram in FIG. The upper side shows the positional relationship between the optical axis O and the center line C of the lead cam of the adjustment barrel 102 when the lens barrel 1 is viewed so as to be a subject. At this time, if a line perpendicular to the optical axis O is taken, the lead cam of the adjusting cylinder 102 is cut so that a line O ′ perpendicular to the optical axis and the center line C of the lead cam of the adjusting cylinder 102 form an acute angle Θ.

  When adjusting the lens interval from the state shown in FIG. 1, even when the adjustment barrel 102 is rotated around the optical axis, the adjustment barrel 102 itself does not move in the thrust direction. On the other hand, the first lens group mirror chamber 101 moves back and forth in the thrust direction by moving along the lead cam of the adjustment barrel 102.

  Further, in order to tilt the first lens 100, the first lens 100 is adjusted by the center adjustment fixed group 110. Describing in more detail, the alignment fixing group 110 is formed of eccentric rollers and screws, and is arranged at a plurality of locations on the outer periphery of the first lens 100. Therefore, the eccentric rollers that are the alignment fixing groups 110 at each position are adjusted so that the first lens 100 is at a predetermined position.

  As a result, the distance between the adjustment barrel 102 and the front ring 105 is always constant regardless of the adjustment amount by the alignment of the first lens 100. When the interval is always constant, the thickness of the cushioning material 104 is determined. Therefore, since it is not necessary to arrange a plurality of sizes of the cushioning material 104 and use them properly depending on the intervals, the number of working steps does not increase.

  Specifically, as shown in FIG. 2, when it is necessary to move the first lens unit barrel 101 to the most object side in the centering step, there is no one that becomes the adjustment barrel 102 in the related art. Since the lens mirror itself moves to the object side, the distance from the front ring 105 is minimized. In contrast, when the first lens unit barrel 101 needs to be moved closest to the image side, the distance between the front ring 105 and the lens chamber becomes maximum because the lens mirror chamber moves to the image side in the related art. If one type of cushioning material 104 is used to cope with both patterns, the cushioning material 104 needs a certain thickness in order to cope with the latter.

  On the other hand, in the case of the cushioning material 104 requiring a certain thickness, in order to cope with the former, since the cushioning material 104 has a certain thickness, the lens barrel 1 is adjusted after the alignment group is adjusted in the alignment process. At the time of assembling, when the front ring 105 is mounted, the front ring 105 is pushed back by the elastic force of the cushioning material 104, so that the mounting of the front ring 105 becomes difficult, or the adjustment is deviated due to a large force applied to the lens mirror chamber. .

  In order to solve the above-mentioned problems, it is necessary to prepare a plurality of cushioning materials 104 having different thicknesses and to take measures such as selecting a cushioning material 104 having an appropriate thickness in accordance with a distance between the front ring 105 and the lens mirror chamber. Becomes possible.

  However, when the above countermeasures are taken, a new problem arises in that the number of work steps of measuring the distance between the adjusted front ring 105 and the lens mirror chamber at the time of assembly and selecting a buffer material 104 suitable for the distance increases.

  In the present invention, such a problem does not occur because the interval between the front rings 105 is constant by including the adjusting cylinder 102 between the first lens mirror chamber 102 and the component holding the cushioning material 104 therebetween.

  Further, in the present invention, it is possible to use the holding ring 108 on the object side of the first lens group mirror chamber 101.

  FIG. 4 is a cross-sectional view of the lens barrel 1 using the holding ring 108.

  In the embodiment of the present invention, as shown in FIG. 1, the cushioning member 104 is wound so as to be directly tightened in the first lens group mirror chamber 101, but a holding ring 108 may be used as shown in FIG. The use of the press ring 108 makes it possible to remove stray light.

  The cushioning material 104 of the present invention is wound around the first lens group mirror chamber 101 or the holding ring 108 so as to be fastened. Therefore, when the lens barrel 1 of the present invention is assembled, the cushioning member 104 and the first lens group mirror chamber 101 or the holding ring 108 are in close contact with each other. Further, as described above, the adjusting cylinder 102 and the front ring 105 are in close contact with each other because the cushioning material 104 suitable for the interval between them is selected. As described above, the cushioning member 104 has a dust-proof and drip-proof function because it is in close contact with any adjacent member in the radial direction and the thrust direction.

  In order to make the cushioning material 104 adhere in the thrust direction, the distance between the optical axis and the inner diameter of the cushioning material 104 is set to the distance from the optical axis to the outer diameter of the first lens group mirror chamber 101. By setting the hardness to 0.90 to 0.95 times in accordance with the hardness, it is possible to more reliably obtain the dust-proof and drip-proof performance. When the press ring 108 is used, the same applies to the distance from the optical axis to the outer diameter of the press ring 108.

1 Lens Barrel 100 First Lens 101 First Lens Group Mirror Chamber 102 Adjusting Tube 104 Buffer Material 105 Front Ring 106 Front Rubber 107 Pressing Ring 108 Makeup Ring 110 Alignment Fixed Group

Claims (2)

A lens mirror room for holding a lens,
An adjustment cylinder used for optical adjustment of the lens mirror chamber,
A front ring for fixing the lens mirror chamber,
In a lens barrel having a dust-proof and drip-proof ring,
The adjusting cylinder forms a lead cam, and the center line of the lead cam forms an acute angle with a line perpendicular to the optical axis of the lens, and is radially outward of the lens with respect to the lens mirror chamber engaged with the lead cam. Position to,
The dustproof drip-proof ring is in contact with the lens mirror chamber in the radial direction, and is sandwiched between the front ring and the adjustment barrel in a thrust direction. The lens barrel according to claim 1,
A holding ring on the outside in the radial direction with respect to the lens mirror chamber,
The dust-proof and drip-proof ring is in contact with the holding ring in the radial direction, and is sandwiched between the front ring and the adjusting cylinder in a thrust direction.

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