JP2013025000A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of arranging a conversion lens close to an imaging lens and downsizing a case.SOLUTION: The imaging apparatus includes: an imaging lens; a conversion lens 104 capable of moving in front of the imaging lens; and a rotary movement mechanism 109 for supporting the conversion lens so as to allow rotational movement with a rotary shaft 105 within a plane which is perpendicular to an optical axis of the imaging lens as the center. The rotary movement mechanism supports the conversion lens so as to allow the rotational movement while being separated from the central shaft so that a locus plotted by a position in the conversion lens which is closest to the rotational shaft in the rotary movement does not interfere with the imaging lens in planes which are perpendicular to the rotational shaft 105.

Description

The present invention relates to the arrangement and structure of an imaging device incorporating a conversion lens.

2. Description of the Related Art Conventionally, in some imaging apparatuses such as video cameras, a conversion lens is arranged in front of an imaging lens in order to capture a wider angle or telescopic field angle than in a normal shooting state. In general, there is a method in which a conversion lens is attached to the filter screw portion provided in front of the imaging lens from the outside (see Non-Patent Document 1). Some imaging devices have a built-in wide conversion lens (see Patent Document 1).

A conventional example of a built-in wide conversion lens will be described. FIG. 8A is a side view of a video camera with a built-in wide conversion lens. Here, for the sake of explanation, internal components are partially made transparent. Reference numeral 201 denotes an imaging lens. A wide conversion lens is disposed in front of the imaging lens 201. 202a is a position when the wide conversion lens is used, and 202b is a position when the conversion lens is not used. The built-in conversion lens can be switched to a non-use position or a use position. Switching is performed by sliding the conversion lens in a direction (arrow direction) perpendicular to the optical axis of the imaging lens 201. The built-in conversion lens covers the front of the imaging lens 201 at the use position, and the built-in conversion lens retracts from the front of the imaging lens 201 at the non-use position. The casing that covers the conversion lens protrudes forward from the tip of the imaging lens 201 by a distance L1. Further, the housing has a height that covers the projection width H1 defined by the position when the conversion lens is used and the position where the conversion lens is not used. On the other hand, a microphone element 203 is disposed in front of the storage position (non-use position) 202b of the wide conversion lens. Since the microphone element 203 in the video camera is intended to record sound from the subject direction, it is preferably arranged in the same direction as the lens. For this reason, the microphone 203 is arranged in front of the storage position of the conversion lens under the imaging lens. FIG. 8B is a partially enlarged cross-sectional view of the imaging lens 201 and the wide conversion lens at the time of use. The conversion lens and the imaging lens 201 are arranged with a gap of a fixed distance X1 in the optical axis direction in order to avoid interference between the two due to the movement of the conversion lens at the time of switching.

JP-A-6-289474

iVIS HFM32 Product Manual p249

However, in the above conventional example, the built-in conversion lens is slid in a plane perpendicular to the optical axis of the imaging lens, and the following points are pointed out. This point will be described with reference to FIG. The front lens of the imaging lens 201 is a convex surface. The side facing the imaging lens 201 of the wide conversion lens at the use position 202a is a concave surface. Therefore, when the conversion lens slides, the end of the conversion lens approaches the apex of the imaging lens 201 (J portion in FIG. 8B). For this reason, it is not easy to place the conversion lens close to the imaging lens, which may lead to an increase in the size of the camera housing.

In view of the above problems, the imaging apparatus of the present invention has the following characteristics. That is, the imaging apparatus includes an imaging lens, a conversion lens that is movable in front of the imaging lens, and a rotational movement mechanism that rotatably supports the conversion lens about a rotational axis in a plane perpendicular to the optical axis of the imaging lens. And comprising. Then, the rotational movement mechanism moves the conversion lens away from the rotational axis so that the locus drawn by the rotational movement does not interfere with the imaging lens in each plane perpendicular to the rotational axis. Supports rotational movement.

According to the image pickup apparatus of the present invention, the built-in conversion lens can be disposed close to the image pickup lens by rotating the built-in conversion lens around the rotation axis as described above. Can be

The external appearance perspective view of the video camera of an Example. The perspective view which shows the inside of the video camera of an Example. The figure which shows the imaging lens and conversion lens of an Example. The figure explaining the rotational movement of the conversion lens of an Example. The figure which shows arrangement | positioning of the imaging lens of a Example, a conversion lens, a conversion lens, and a microphone. The figure of the imaging lens of a Example, a wide conversion lens, and a rotational movement mechanism. The figure explaining the rotational movement mechanism of an Example. The figure of the video camera of an Example. The figure of the video camera which incorporated the conventional wide conversion lens.

A feature of the present invention is that the conversion lens is rotatably supported around a rotation axis in a plane perpendicular to the optical axis of the imaging lens. However, it is necessary that the locus drawn by the rotation movement of the conversion lens does not interfere with the imaging lens anywhere. For this purpose, the rotational movement mechanism is separated from the rotational axis so that the locus drawn by the rotational movement of the latest conversion lens on the rotational axis does not interfere with the imaging lens in each plane perpendicular to the rotational axis. Is supported so as to be rotatable.

Examples will be described below. As an embodiment of the imaging apparatus of the present invention, a video camera incorporating a wide conversion lens will be described with reference to the drawings. First, an overview of the entire video camera necessary for describing the present embodiment will be described. In FIG. 1, which is a perspective view of the video camera of this embodiment, 101 is an imaging lens. Light that enters the imaging lens 101 can be converted into an electrical signal by an imaging sensor and recorded. Reference numeral 102 denotes a display unit. The display unit 102 can display an image being shot. Reference numeral 103 denotes a microphone unit. The microphone unit 103 can convert sound being shot into an electric signal.

Next, an outline of the conversion lens of the present embodiment (here, a wide conversion lens) will be described. As shown in FIG. 2 showing the inside of the video camera of this embodiment, a wide conversion lens 104 is built in the main body. FIG. 2A shows a state where the wide conversion lens 104 is retracted from the front surface of the imaging lens 101. This is a normal shooting state in which shooting is performed without using the wide conversion lens 104. Hereinafter, such a state is referred to as a storage state or a storage position of the wide conversion lens 104. FIG. 2B shows a state in which the wide conversion lens 104 is overlapped with the front surface of the photographing lens 101. In this state, imaging can be performed using the wide conversion lens 104. Compared to the normal shooting state, a wide-angle image can be taken. Hereinafter, such a state is referred to as a use state or a use position of the wide conversion lens 104. As described above, the wide conversion lens 104 of the present embodiment can be moved to two positions, the use state and the storage state.

Next, a basic drive structure of the wide conversion lens of this embodiment will be described. FIG. 3 is a perspective view of the imaging lens 101 and the wide conversion lens of the video camera of this embodiment. 104a is a storage state of the wide conversion lens. 104b is a use state of the wide conversion lens. The wide conversion lens of this embodiment rotates about the rotation axis 105 between the housed state and the used state.

The positions of the wide conversion lens and the rotating shaft 105 of this embodiment will be described. In the usage state of the wide conversion lens 104 in FIG. 4A, the wide conversion lens 104 covers the front of the imaging lens 101. The optical axes of the wide conversion lens and the imaging lens are 104-X. FIG. 4B is a schematic cross-sectional view taken along a plane that passes through the optical axis 104-X in FIG. In the imaging lens 101, 101a is a cross section of the front lens on the forefront. The cross section at the storage position of the wide conversion lens is 104a. The cross section at the position where the wide conversion lens is used is 104b. The wide conversion lens is rotationally moved with a straight line passing on a plane perpendicular to the optical axis 104-X as a rotation axis 105 (axis perpendicular to the paper surface of FIG. 4B). In the present embodiment, the portion (frontmost surface of the imaging lens) facing the wide conversion lens 104 of the front lens 101a of the imaging lens is a spherical surface. Therefore, the cross section becomes an arc when cut along a plane passing through the optical axis 104-X. In this embodiment, the arc center (curvature center) 106 of the front lens 101a of the imaging lens is set on the rotation axis 105 of the wide conversion lens 104. By setting the rotation shaft 105 so as to pass through the arc center 106, the movement locus of the wide conversion lens 104 can be kept away from the front lens 101a of the imaging lens. That is, in each plane perpendicular to the rotation axis 105, the conversion lens is the minimum necessary from the rotation axis 105 so that the locus drawn by the rotational movement of the conversion lens 104 closest to the rotation axis 105 does not interfere with the front lens 101a. It is supported so that it can be rotated and moved away by a distance of. Therefore, the front lens 101a of the imaging lens and the wide conversion lens 104 can be disposed close to each other.

As described above, as shown in FIG. 4B, the front lens apex portion of the imaging lens is embedded in the concave portion of the wide conversion lens 104 and can be arranged close to each other. That is, the front lens can be placed in the concave portion of the wide conversion lens so as to be submerged in the width of X2. As shown in Fig. 8 (b), the X1 gap is no longer necessary compared to the X1 required for the gap between the imaging lens and the wide conversion lens. You can place them together. As a result, the casing length in front of the imaging lens can be shortened from L1 in FIG. 8A to L2 shown in FIG. 4C, and the overall size can be reduced. Further, in this embodiment, by rotating the wide conversion lens, as shown in FIG. 4B, the height of the wide conversion lens in the housed state becomes D, which is higher than the height C in the used state. Lower. As a result, the height necessary for moving the wide conversion lens is conventionally H1 as shown in FIG. 8A, but in this embodiment, the height necessary for covering the storage position and the use position. Becomes H2 shown in FIG. As described above, the front length and height of the video camera can be reduced.

Next, details of the imaging range and the rotational movement range of the wide conversion lens of this embodiment will be described. FIG. 5A is a perspective view of the imaging lens 101 of this embodiment. An image that can be photographed by the video camera of this embodiment is a wide image having a horizontally long aspect ratio of 16: 9. Therefore, the optically used range on the surface of the front lens 101a of the imaging lens is a horizontally long range 107. During normal shooting without using the wide conversion lens, the wide conversion lens 104 needs to be completely retracted from the front surface of the 107 range.

On the other hand, when the wide conversion lens 104 is used, a wide image is similarly captured. The optically used range of the wide conversion lens 104 is also a horizontally long range. In this embodiment, a molded lens is used as the wide conversion lens 104, and a horizontally long wide conversion lens 104 made in a necessary size is used. In such a video camera that captures a wide image, when moving the horizontally long wide conversion lens 104, it is rotated to the vertical side (arrow E) where the imaging range is small, thereby reducing the amount of movement and saving the space. Can be stored. That is, here, in an imaging device capable of capturing a rectangular image having a long side and a short side, the rotation axis 105 for rotational movement of the conversion lens is arranged in parallel with the long side.

Next, the arrangement of the wide conversion lens and the microphone will be described. FIGS. 5B and 5C are a front view and a side view showing the arrangement of the wide conversion lens and the microphone. It is a figure in the storage position 104a of a wide conversion lens. Reference numeral 108 denotes a microphone element. In this embodiment, the wide conversion lens rotates up and down. The wide conversion lens 104 disposed in front of the imaging lens at the use position moves rearward from the front lens of the imaging lens at the storage position. Therefore, there is an F area where the movement locus of the wide conversion lens is not applied. In the present embodiment, the microphone element 108 is disposed in the F area. As shown in FIG. 8A of the conventional example, the arrangement of the microphone element 203 when the wide conversion lens slides is in front of the wide conversion lens. When the wide conversion lens slides, the wide conversion lens moves on the same surface. For this reason, the microphone element 203 has to be disposed so as to protrude forward of the storage position 202b of the wide conversion lens. On the other hand, in this embodiment, the microphone element 108 can be arranged under the imaging lens in the F area. As a result, the housing can be downsized without protruding the microphone portion.

Next, a rotational movement mechanism that rotatably holds the wide conversion lens will be described. FIG. 6A is a perspective view of the imaging lens 101 and the wide conversion lens 104. Reference numeral 109 denotes a lens holder that holds a wide conversion lens. A lens holder 109 that forms the main part of the rotational movement mechanism surrounds the outer periphery of the side surface of the wide conversion lens, and holds the wide conversion lens 104 by fitting it. The wide conversion lens 104 is a translucent member, and light enters from the outer peripheral side surface. As a result, unintended light may enter the captured image. In this embodiment, a non-light-transmitting material is used for the lens holder 109, and the outer peripheral side surface of the wide conversion lens 104 is completely covered with the lens holder 109. Thereby, the entrance of light from the outer peripheral side surface can be prevented.

The lens holder 109 is provided with a shaft hole 110 for rotating the wide conversion lens 104. On the other hand, the lens barrel of the imaging lens 101 is provided with a boss shape 111 serving as a rotation shaft 105. A shaft hole 110 of the lens holder is fitted into a boss shape 111 that defines the rotation axis of the imaging lens, and the lens holder 109 is rotatably held. Further, the lens holder 109 is provided with a notch 112 for reliably holding the position of the wide conversion lens 104 at the use position. The imaging lens barrel is provided with a boss shape 113 serving as a stopper. When the lens holder 109 is moved to a position where the end face of the notch 112 of the lens holder abuts against the boss shape 113 of the imaging lens, the wide conversion lens 104 is accurately placed at the use position (state shown in FIG. 6B). . Thus, since the lens barrel that holds the imaging lens is provided with the rotation movement mechanism of the conversion lens, the accuracy of the relative position between the conversion lens and the imaging lens can be improved.

The rotational movement mechanism of the wide conversion lens will be further described. FIG. 6B shows a lens holder 109 for the wide conversion lens, a spring 114 for holding the position of the wide conversion lens 104, an operation knob 115, and an arcuate guide 120. The lens holder 109, the spring 114, the arcuate guide 120, and the like are on both sides of the imaging lens 101. The operation knob 115 is provided with an operation portion 115a for switching the wide conversion lens 104 between the use position and the storage position, and a boss shape 115b for moving the lens holder 109. The lens holder 109 is provided with an elongated hole portion 116 into which the boss shape 115b of the operation knob is fitted. Accordingly, by operating the operation knob 115 up and down, the lens holder 109 rotates about the rotation shaft 105, and the wide conversion lens 104 can be switched between the use position and the storage position. The lens holder slot 116 that is fitted to the boss 115b of the operation knob is provided on the opposite side of the wide conversion lens 104 with the rotating shaft 105 interposed therebetween. Therefore, when the operation knob 115 is raised, the wide conversion lens 104 is lowered to the storage position. When the operation knob 115 is lowered, the wide conversion lens 104 is raised to the use position. The spring 114 is a torsion spring. The spring 114 is bent at both ends. In the assembled state, both ends are set to be urged in the opening direction. The lens holder 109 has a hole 117 for hooking one end of the spring 114. One end of the spring 114 is hooked in the hole 117 of the lens holder, and the other end of the spring 114 is fixed by another member (not shown). The arcuate guide 120 lightly contacts the inner surface of the lens holder 109 to guide the movement of the lens holder 109. The upper end of the arcuate guide 120 is slightly fan-shaped, and when the inner surface of the lens holder 109 approaches the contact resistance between the two, the lens holder 109 also acts as a brake to stop the lens holder 109 at the use position. . As a result, the rotational movement of the lens holder 109 around the rotation shaft 105 is performed reliably and stably.

Next, the rotational movement of the wide conversion lens will be described in detail using a side view. FIG. 6C is a side view of the wide conversion lens 104 in use. For simplification of the drawing, the operation portion 115a of the operation knob is omitted, and only the boss shape 115b (hatched display portion) that fits into the elongated hole portion 116 of the lens holder 109 is shown. In this use state, the lens holder 109 is biased in the G direction by the spring 114. In this state, the notch 112 end face of the lens holder is in contact with the boss shape 113 of the imaging lens. Thereby, the lens holder 109 is held at the use position. When the operation knob 115 is operated upward from this state, the lens holder 109 rotates with the rotation shaft 105 as a fulcrum. When the lens holder 109 rotates, the spring 114 also rotates with the fixed end as a fulcrum. As a result, the spring 114 that urges the lens holder 109 in the use position direction reverses as the rotation of the lens holder 109 proceeds, and the lens holder 109 is urged in the direction of the storage position (H direction). become. FIG. 6B is a side view of the storage position of the wide conversion lens 104. In this state, the lens holder 109 is biased in the H direction by the spring 114. The position of the lens holder 109 is held by a stopper of another member (not shown) so as not to further rotate from the storage position.

As described above, the positions of the lens holder 109 and the imaging lens 101 of the wide conversion lens 104 in this embodiment are defined by being directly connected to the stopper and the rotation shaft 105 provided in the imaging lens barrel. Thereby, it is possible to improve the arrangement accuracy of the wide conversion lens 104 at the use position with respect to the position of the imaging lens.

Next, the layout of the operation knob 115 in the entire video camera will be described. FIG. 7 is a perspective view of the video camera of this embodiment. FIG. 7 shows a state in which the display unit 102 is opened. When the display unit 102 is opened, the display screen 118 is exposed. The user can open the display unit 102 and take a picture while confirming the image displayed on the display screen 118. The operation knob 115 is disposed inside the display unit 102 when it is opened. The operation knob 115 of this embodiment is provided on the left side of the main body as viewed from the photographer so that it can be operated using the left hand. Thus, even when the video camera being shot is held and held with the right hand, the operation knob 115 can be easily operated with the left hand. The wide conversion lens of the present embodiment has a configuration in which a rotation shaft 105 provided on the side surface of the imaging lens 101 is rotationally moved about a fulcrum. Therefore, the rotational movement mechanism of the wide conversion lens 104 is arranged on the side surface of the imaging lens. When the operation knob 115 is arranged inside the display unit 103, the position of the operation knob 115 is in the vicinity of the rotational movement mechanism of the wide conversion lens 104. Therefore, the operation knob 115 can be directly connected to the components of the rotational movement mechanism such as the lens holder 109, so that the number of components can be reduced and the housing can be downsized.

As described above, the embodiments for realizing the miniaturization in the present invention have been described. However, the present invention is not limited to such specific embodiments, and the following forms are also included in the present invention. That is, in the above embodiment, the wide conversion lens has been described as an example, but the present invention can be applied to a lens having other optical characteristics. In the above embodiment, the rotation axis of the conversion lens is provided so as to pass through the center of the arc in the optical center cross section (cross section including the optical axis) of the imaging lens. However, the rotation axis position of the conversion lens is not limited to this position, and may be arranged at other positions such as the vicinity of the arc center.

101 ... Imaging lens, 104 ... Wide conversion lens (conversion lens), 105 ... Rotating shaft, 109 ... Lens holder (Rotary movement mechanism)

Claims (4)

An imaging lens;
A conversion lens movable on the front side of the imaging lens;
A rotational movement mechanism that rotatably supports the conversion lens around a rotational axis in a plane perpendicular to the optical axis of the imaging lens;
With
The rotational movement mechanism is separated from the rotational axis so that the locus drawn by the rotational movement of the portion of the conversion lens closest to the rotational axis does not interfere with the imaging lens in each plane perpendicular to the rotational axis. And supporting the conversion lens in a rotatable manner,
An imaging apparatus characterized by that. The forefront of the imaging lens is a spherical surface,
The imaging apparatus according to claim 1, wherein the rotation axis of the rotational movement of the conversion lens passes through the vicinity of the center of curvature of the frontmost spherical surface of the imaging lens. An imaging device capable of capturing a rectangular image having a long side and a short side,
The imaging apparatus according to claim 1, wherein the rotation axis of the rotational movement of the conversion lens is arranged in parallel with the long side. A lens barrel that holds the imaging lens;
The imaging apparatus according to claim 1, wherein a rotation moving mechanism of the conversion lens is provided in the lens barrel.

Images