JP2018105960A - Lens barrel and image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel having a reduced risk of falling off while reducing the weight. SOLUTION: A first tubular member 30a is formed so as to hold a lens 15 and have a first helicoid screw 31a having a plurality of threads 32 on the outer peripheral side, and a second screw thread 32 is formed so as to mesh with the screw thread 32. The first helicoid screw 31a has a screw thread 32 and a lower portion 33 having a height different from that of the screw thread 32, and has a second tubular member 20 provided with a helicoid screw 22a. A lens barrel 200 characterized in that, in a state where the helicoid screw 31a is meshed with the second helicoid screw 22a, the lower portion 32 forms a gap 35 with the second helicoid screw 22a within the meshed range. [Selection diagram] Fig. 2

Description

  The present invention relates to a lens barrel and an image projection apparatus.

  In an optical device such as a camera or a projector, such as an image projection device using a lens unit, a configuration that adjusts optical characteristics such as focal length by rotating a part of the lens barrel to move the lens position back and forth. Is known (see, for example, Patent Document 1).

As an example of such a configuration, a structure is known in which a helicoid screw is formed on a pair of cylindrical members constituting a lens barrel and the positions of the lenses are adjusted in the front-rear direction by rotating each other.
In recent optical apparatuses, particularly lens barrels of image projection apparatuses, weight reduction and weight reduction are regarded as important. For example, a method of reducing the number of screw threads engaged with a helicoid screw is conceivable.
However, simply reducing the number of threads may reduce the force to hold the lens barrel and cause problems such as dropout.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a lens barrel that reduces the risk of dropping while achieving weight reduction.

  In order to solve the above-described problems, a lens barrel according to the present invention includes a first cylindrical member that holds a lens and has a first helicoid screw having a plurality of threads on the outer peripheral side, and the screw thread. A second cylindrical member provided with a second helicoid screw formed to mesh with the first helicoid screw, the thread and the lower part having a height different from the thread, In the state where the first helicoid screw meshes with the second helicoid screw, the lower portion forms a gap with the second helicoid screw within the meshed range.

  According to the present invention, it is possible to reduce the risk of falling off while reducing the weight.

It is a figure which shows an example of a structure of the image projector in embodiment of this invention. It is a figure which shows an example of a structure of the lens-barrel in embodiment of this invention. It is a figure which shows an example of the shape of the helicoid screw formed in the cylindrical member shown in FIG. It is a figure which shows an example of the shape of the helicoid screw formed in the housing | casing shown in FIG. It is an enlarged view which shows an example of a structure of the helicoid screw shown in FIG. It is a figure which shows the state which the lens-barrel shown in FIG. 2 meshed | engaged. It is a figure which shows the operation | movement in the screwing state of the helicoid screw shown in FIG. It is a figure which shows the modification of a structure of the lens-barrel in embodiment of this invention.

As an embodiment of the present invention, an example of the configuration of an image projection apparatus is shown in FIG.
The image projection apparatus 100 includes a light source 101 that emits a light beam and a spatial light modulation element 102 that displays an image to be projected and gives image information to the transmitted light beam.
The image projection apparatus 100 also includes a lens unit 200 that is a projection optical system for projecting an image on the display surface 104, and a control unit 109 that controls the spatial light modulator 102 to display an image to be projected on the display surface 104. And have.

The light source 101 emits white light substantially in parallel using a halogen lamp that is a light source that emits light. Here, a metal halide lamp, a high-pressure mercury lamp, or an LED may be used as the light source.
Although the light source 101 is a white light source, a plurality of monochromatic light sources such as laser light sources corresponding to basic colors such as R, G, and B may be used.

  The spatial light modulation element 102 is a liquid crystal panel that is an image display means that provides image information by transmitting an incident light beam, applying spatial modulation, and emitting the light. The spatial light modulator 102 may be a reflective spatial light modulator such as a DMD (digital micromirror device).

The configuration of the lens unit 200 will be described.
Here, in the normal posture state to be described later, the optical axis of the incident light to the lens unit 200, that is, the lens optical axis is the Z axis, and the direction perpendicular to the Z axis in FIG. An axis perpendicular to the Z axis and the Y axis is defined as the X axis. For the directions of the X axis, the Y axis, and the Z axis, the directions of the arrows shown in FIG.

As shown in FIG. 2, the lens unit 200 is arranged on the Z axis to constitute at least one lens 15 constituting the projection optical system, and a pair of lens barrel portions 30 a serving as a first cylindrical member that holds the lens 15. , B.
The lens unit 200 includes a housing 20 that is a second cylindrical member that is attached to the image projection apparatus 100 and serves as an immovable member of the lens unit 200, that is, an immovable member fixed at a fixed position.
The lens unit 200 includes connection pins 21a and 21b that are fixing portions for connecting the housing 20 and the lens barrel portions 30a and 30b, respectively.
With this configuration, the lens unit 200 has a function as a lens barrel that holds the lens 15.

The light beam emitted from the light source 101 is given image information by passing through the spatial light modulation element 102 disposed on the −Z direction side of the lens unit 200, and passes through the lens unit 200 to be emitted to the display surface 104. Is done.
In order for the lens unit 200 to correctly display an image on the display surface 104, it is necessary to adjust the positional relationship with the display surface 104 and the spatial relationship with the spatial light modulator 102.
Therefore, in the present embodiment, as shown in FIG. 3, the lens barrel portions 30a and 30b have first helicoid screws 31a and 31b, which are helical helicoid screws, on their outer peripheral portions.

  The housing 20 has a second helicoid screw 22a shown in FIG. 4 formed in a spiral shape so as to mesh with the first helicoid screw 31a on the inner peripheral side facing the first helicoid screw 31a. The housing 20 similarly has a second helicoid screw 22b formed to face the first helicoid screw 31b.

  In the following description, the lens barrel portion 30a and the first helicoid screw 31a formed on the outer peripheral side of the lens barrel portion 30a will be described, but the lens barrel portion 30b and the lens barrel portion 30b on the outer peripheral side will be described. The same applies to the formed first helicoid screw 31b.

As shown in FIG. 5 which is an enlarged view of the portion indicated by A in FIG. 3, the first helicoid screw 31a is a screw thread portion 32 having a thread height h1 and having a trapezoidal cross section. It has a lower portion 33 having a height h2 different from the thread portion 32.
In other words, on the surface on which the first helicoid screw 31a is formed, a part of the thread portion 32 is removed along the circumferential direction to form a spiral groove-shaped low portion 33.
In the present embodiment, the low portion 33 is formed in such a manner that it is further cut away from the reference plane O serving as a reference toward the inner peripheral side, but is not limited to this configuration. For example, the height may be higher than the reference plane O and lower than the thread portion 32.
Thus, in this embodiment, a part of the thread part 32 of the helicoid screw 31a on the male screw side is cut out. Further, as will be described later, the thread portion 32 and the low portion 33 are connected to each other by a standing wall surface 34.
That is, the low part 33 is a groove formed in a spiral shape along the shape of the helicoid screw 31 a, and both ends thereof are surrounded and defined by the wall surface 34.

  An operation for adjusting the position of the lens 15 on the Z-axis using the casing 20 and the lens barrel 30a having such a configuration will be described.

First, when attaching the housing 20 and the lens barrel portion 30a, as shown in FIG. 6A, the lens barrel portion 30a with respect to the housing 20 so that the first helicoid screw 31a and the second helicoid screw 22a are engaged with each other. Rotate.
When the first helicoid screw 31a, which is a male screw, meshes with the second helicoid screw 22a, which is a female screw, at least one thread, that is, one turn in the circumferential direction, the lens barrel 30a is supported by the housing 20. Thus, the state in which the first helicoid screw 30a and the second helicoid screw 22a mesh with each other and the lens barrel portion 30a is supported by the housing 20 is referred to as a screwed state.

In such a screwed state, a gap 35 is formed between the low portion 33 and the housing 20 by a difference between the height h1 of the screw thread portion 32 and the height h2 of the low portion 33.
That is, the gap portion 35 is a space surrounded by the low portion 33, the second helicoid screw 22 a, and the wall surface 34.
In this way, by setting a part of the first helicoid screw 31a as the low part 33, a part of the lens barrel part 30a is thinned, so that the screwed state with the housing 20 is not loosened. Reduced weight.
That is, the risk of dropping while reducing the weight of the lens barrel 30a is reduced.

Now, in a general lens barrel, when moving the lens barrel portion in the direction along the optical axis for the purpose of adjusting the focal length or the like, a pin or the like is used so that the moving distance of the lens is within a predetermined range. In many cases, a member that restricts rotation, such as a cam groove, is provided.
However, in recent lens barrels, it is difficult to secure a space for providing such a rotation restricting member separately due to demands for shortening the focal length, reducing the size, and the like.

Therefore, in the present embodiment, the connection pins 21a and 21b are inserted toward the gap portion 35 as shown in FIG.
Each of the connecting pins 21a and 21b is a fastening member that is inserted through the housing 20 and connected to the lens barrel portions 30a and 30b in a screwed state of the housing 20 and the lens barrel portion 30a.
The connecting pin 21a rotates integrally with the inside of the gap 35 when the housing 20 rotates. That is, when the housing 20 and the lens barrel 30a rotate with each other, the connecting pin 21a moves in the gap 35 as shown in FIGS. 7 (a) and 7 (b). FIG. 7B shows a state when FIG. 7A is rotated.
As already described, since the gap portion 35 is a groove-like portion formed along the first helicoid screw 22a, the operation of the connecting pin 21a is performed with the wall portions 34 disposed at both ends of the gap portion 35. It is regulated by contacting. With this configuration, the connecting pin 21a functions as a rotation restricting member. Therefore, the connection pin 21a, which is a rotation restricting member, is supported so as to be able to move in the space 35 formed in a spiral shape.

In FIGS. 2, 6A, and 6B, the connecting pin 21a is a member that is inserted through the housing 20 and rotates integrally. However, the connecting pin 21a is a pin or a protrusion fixed to the housing 20. Alternatively, it may be attached to the lens barrel 30 side.
In addition, in order to suppress the increase in the process at the time of attachment, as demonstrated in this embodiment, a through-hole is formed in the housing | casing 20, and it attaches in the aspect which inserts the connection pin 21a in a screwing state. desirable.
In the present embodiment, the rotation is regulated by the connection pin 21a coming into contact with the wall portion 34, but the present invention is not limited to this configuration.
For example, it may be fixed by being pushed toward the low portion 33 at a predetermined position and the connecting pin 21a and the low portion 33 coming into contact with each other.

In the present embodiment, the lens unit 200 is formed so as to mesh with the threaded portion 32 and the lens barrel portion 30a formed with the first helicoid screw 31a that holds the lens 15 and has the threaded portion 32 on the outer peripheral side. And a housing 20 having a second helicoid screw 22a.
The first helicoid screw 31 a includes a thread portion 32 and a low portion 33 having a height different from that of the thread portion 32.
With this configuration, the lens barrel portion 30a is reduced in thickness so that the weight is reduced.
Furthermore, in the screwed state in which the first helicoid screw 31a is engaged with the second helicoid screw 22a, a gap 35 is formed between the low portion 33 and the second helicoid screw 22a within the engaged range. With this configuration, it is possible to reduce the possibility of falling off while reducing the weight.

In the present embodiment, the lens unit 200 rotates with the housing 20 in the gap 35 and restricts rotation of the housing 20 and the lens barrel 30a on the condition that the lens unit 200 contacts the lens barrel 30a. It has a connecting pin 21a.
With this configuration, the range in which the housing 20 and the lens barrel portion 30a rotate with each other is restricted within the range in which the gap portion 35 is formed. That is, it is not necessary to provide a rotation restricting member separately from the helicoid screw, which contributes to space saving.

Further, as a modification of the first embodiment, a lens unit 200 is shown in FIGS.
In this modification, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
The lens unit 200 includes a motor 36 that is a driving unit for driving the lens barrel 30 a and a drive control unit 37 for controlling the motor 36.
The drive control unit 37 is a semiconductor electronic substrate, detects its mounting position, that is, the rotation angle θ with respect to the housing 20, and controls the motor 36 to adjust the position of the lens 15.

The drive control unit 37 is disposed in the gap 35 at a position where it does not interfere with the connecting pin 21a, and the motor is routed through a portion where the wiring is a gap between the gap 35 and the first helicoid screw 31a. 36.
With this configuration, the control of the rotation angle θ, which is the phase of rotation between the housing 20 and the lens barrel 30a, can be completed inside the lens unit 200 without being separately performed, so that space is saved.

In this modification, the drive control unit 37 for controlling the motor 36 is arranged inside the gap portion 35. However, the present invention is not limited to this configuration. For example, the position of the lens 15 is determined from the rotation angle θ. It is good also as arranging the sensor and other parts which distinguish.
As described above, by arranging the components inside the gap portion 35 formed along the first helicoid screw 31a, the space of the lens unit 200 can be saved.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

  For example, the image projector is a single-plate color projector that provides color image information with a single liquid crystal panel, but is not limited thereto, and may be a three-plate color projector or a monochrome image projector. There may be.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

20 Second cylindrical member (housing)
21a, 21b Rotation restricting member (connecting pin)
22a, 22b 2nd helicoid screw 30a, 30b 1st cylindrical member (lens barrel part)
31a, 31b First helicoid screw 32 Thread (thread portion)
33 Low part 34 Wall part 35 Gap part 100 Image projector 200 Lens barrel (lens unit)

JP 2003-090947 A

Claims (5)

A first tubular member holding a lens and having a first helicoid screw having a plurality of threads on the outer peripheral side;
A second tubular member provided with a second helicoid screw formed to mesh with the thread,
The first helicoid screw has the screw thread and a lower part having a height different from that of the screw thread,
The lens barrel characterized in that, in a state in which the first helicoid screw is engaged with the second helicoid screw, the lower portion forms a gap with the second helicoid screw within the engaged range. The lens barrel according to claim 1,
A rotation restricting member that restricts rotation of the first tubular member and the second tubular member on the condition that it rotates together with the second tubular member in the gap and is in contact with the first tubular member. A lens barrel comprising: The lens barrel according to claim 1 or 2,
A lens barrel having a member disposed in the gap. In the lens barrel according to claim 3,
A lens barrel, wherein the member is an electronic substrate. The lens barrel according to any one of claims 1 to 4,
A light emitting source that emits light toward the lens barrel;
And projecting the light transmitted through the lens barrel onto a display surface.

Images