JP4717529B2 - Optical system tilt drive mechanism - Google Patents

Description

  The present invention relates to a tilt drive mechanism of an optical system having an optical element and a reflective optical element, and an imaging apparatus including the same.

  In an imaging apparatus, for example, an imaging apparatus that forms an image of infrared light incident through an optical system including an objective lens and a mirror having a reflecting surface onto an infrared detection element, if disturbance such as shaking is applied to the imaging apparatus, The infrared light incident on the mirror via the lens is tilted, and the infrared light reflected by the mirror is also tilted. As a result, the imaging position of the reflected infrared light with respect to the infrared detection element moves, and image blurring occurs.

In order to suppress the occurrence of image blurring, a link mechanism that rotatably supports a mirror and a mechanism that arranges a motor for driving the link mechanism behind the mirror are known (for example, Patent Documents). 1). In this mechanism, in order to prevent the image formation position of the infrared light reflected by the mirror from moving relative to the infrared detection element, according to the tilt amount of the device detected by the angle sensor attached to the imaging device. The drive of the motor is controlled so as to rotationally drive the mirror via the link mechanism. Here, the rotation center axis of the mirror is located at the intersection of the incident optical axis and the reflected optical axis of the mirror.
JP 2000-171845 A

  However, in the above conventional example, when the apparatus is inclined by the angle θ, the infrared light is incident with an angle θ inclined with respect to the optical axis of the objective lens. It is necessary to provide means for rotating the angle θ to match the optical axis direction of the objective lens with the incident direction of infrared light.

  An object of the present invention is to provide an optical system tilt drive mechanism capable of tilting a photographing optical axis of an optical system to a desired angle by swinging an optical element and a reflective optical element, and an imaging apparatus including the same. There is.

  In order to achieve the above object, the present invention includes an optical element having a first optical axis and a reflective optical element disposed behind the optical element, and the first optical element is separated from the optical element by the reflective optical element. In the tilt drive mechanism of the optical system configured to guide the light emitted along the optical axis of the optical system in a direction along the second optical axis orthogonal to the first optical axis, the optical element and the reflection A first swinging means for swinging the optical element integrally with the first position as a fulcrum; and a second swing for swinging the optical element with respect to the reflective optical element with the second position as a fulcrum. And a tilt drive mechanism for the optical system.

  In order to achieve the above object, the present invention provides an imaging apparatus including a tilt driving mechanism for the optical system.

  According to the present invention, the optical element and the reflective optical element are integrated and oscillated with the first position as a fulcrum, and the optical element is oscillated with respect to the reflective optical element as the fulcrum. The imaging optical axis of the system can be tilted to a desired angle.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a reflective optical system assembly incorporating a tilt drive mechanism according to an embodiment of the present invention as viewed from the front side, and FIG. 2 is a perspective view of the reflective optical system assembly of FIG. 3 is an exploded perspective view of the reflective optical system assembly of FIG. 1, FIG. 4 is a diagram schematically showing a configuration of the reflective optical system in the reflective optical system assembly of FIG. 1, and FIG. 5 is a prism of FIG. 6 schematically shows a change in the tilt direction of the photographing optical axis when rotating 2, and FIG. 6 shows the objective lens holder 7 of the reflective optical system assembly of FIG. 1 supported by the prism holder 8 by the cam pin 19. FIG. 7 is a perspective view of the tilted state of the reflective optical system assembly of FIG. 1 as seen from the back side.

  In the present embodiment, a tilt drive mechanism that is incorporated in an imaging apparatus and used in a reflection optical system having at least an objective lens (optical element) and a prism (reflection optical element) will be described. First, the reflection optical system will be described with reference to FIGS.

  The reflection optical system has an objective lens 1 and a prism 2 as shown in FIG. The prism 2 is disposed behind the objective lens 1 and has an incident surface portion 2 a, an exit surface portion 2 b, and a reflective surface portion 2 c that face the objective lens 1. The prism 2 acts so that light incident on the incident surface portion 2a along the incident optical axis is reflected by the reflecting surface portion 2c, guided in an emission optical axis direction orthogonal to the incident optical axis, and emitted from the emission plane portion 2b. The first cemented lens 3 is fixed to the incident surface 2a of the prism 2, and the second cemented lens 4 is fixed to the exit surface 2b. The first cemented lens 3 is arranged coaxially with the incident axis of the prism 2, and the second cemented lens 4 is arranged coaxially with the emission optical axis of the prism 2. A lens group 5 and an image sensor 6 are disposed behind the second cemented lens 4.

  In such a reflection optical system, photographing light that has passed through the objective lens 1 is incident on the prism 2 via the first cemented lens 3, and the incident photographing light is incident on the reflecting surface portion 2 c of the prism 2. It is reflected toward the direction of the exit optical axis perpendicular to the axis. Then, the light reflected by the reflection surface portion 2 c of the prism 2 is emitted from the emission surface portion 2 b and forms an image on the image sensor 6 through the second cemented lens 4 and the lens group 5.

  Here, an optical axis A and an optical axis B in the figure are preset reference optical axes, and the objective lens 1, the prism 2, the lens group 5, and the imaging are based on these optical axes A and B. Element 6 is incorporated. For example, the objective lens 1 is incorporated so that the optical axis thereof coincides with the optical axis A, and the prism 2 is incorporated so that the incident optical axis thereof coincides with the optical axis A and the outgoing optical axis thereof. Further, the lens group 5 and the image pickup device 6 are incorporated coaxially with the optical axis B. Here, the state in which the objective lens 1, the prism 2, the lens group 5, and the image sensor 6 are incorporated with reference to the optical axes A and B is referred to as an initial state. It is assumed that the tilt angle is equivalent to 0 (rad).

  Next, a change in the tilt direction of the photographing optical axis when the prism 2 is rotated in order to perform so-called tilt photographing in which photographing is performed by changing the photographing field up and down will be described.

  For example, as shown in FIG. 5, the reflecting surface 2c of the prism 2 is inclined by an angle θ from the state indicated by the solid line in the figure, with the intersection of the optical axis A and the optical axis B in the reflecting surface 2c of the prism 2 as the center ( When the prism 2 is rotated until the state shown by the broken line), the prism 2 is in a state where the incident optical axis is inclined with respect to the optical axis A at an angle 2θ. For this reason, similarly, it is necessary to incline the optical axis of the objective lens 1 with respect to the optical axis A by an angle 2θ. That is, in such a reflection optical system, when the prism 2 is rotated by an angle θ around the intersection of the optical axis A and the optical axis B in the reflection surface portion 2c, the objective lens 1 is moved around the intersection. It is necessary to rotate the angle by 2θ.

  Therefore, the present embodiment is a reflection optical system that tilts the photographic optical axis without rotating the objective lens 1 and the prism 2 around the intersection of the optical axis A and the optical axis B in the reflecting surface 2c of the prism 2. A tilt drive mechanism is used.

  Specifically, the tilt drive mechanism first swings the objective lens 1 and the prism 2 together with the first position as a fulcrum. Here, as shown in FIG. 4, the first position is a position B4R which is the R center of the R surface 4a of the second cemented lens 4. The position B4R is formed by integrating the objective lens 1 and the prism 2. Thus, it is a fixed position on the optical axis B that does not move even when it is swung.

  Here, the case where the tilt angle of the reflection optical system (tilt angle from the initial state) is set to 2θ will be described. In the present embodiment, when the objective lens 1 and the prism 2 are swung together from the initial state (tilt angle = 0 (rad)), the incident optical axis and the optical axis A of the prism 2 are formed. It is assumed that the angle is 2θ and the angle θ formed by the optical axis of the objective lens 1 and the optical axis A is configured. In this case, in order to set the angle formed by the optical axis of the objective lens 1 and the optical axis A to 2θ, it is necessary to further swing only the objective lens 1 by the angle θ with respect to the prism 2. For this reason, when the objective lens 1 is moved integrally with the prism 2 around the position B4R, the objective lens 1 is further swung with respect to the prism 2 with the second position as a fulcrum. The The second position serving as the fulcrum of this swing is a position A1R that is the R center of the R surface 1a of the objective lens 1, and is located on the optical axis of the objective lens 1. This position A1R is located on the optical axis A in the initial state, but moves as the objective lens 1 is swung together with the prism 2.

  The swing of the objective lens 1 with respect to the prism 2 is performed to correct the angle formed by the optical axis of the objective lens 1 and the optical axis A to a predetermined angle, that is, 2θ. That is, the objective lens 1 is further moved relative to the prism 2 so that the angle formed by the optical axis of the objective lens 1 and the optical axis A is 2θ. Thereby, it is possible to make the inclination of the incident optical axis of the prism 2 with respect to the optical axis A coincide with the inclination of the optical axis of the objective lens 1.

  In this way, the objective lens 1 and the prism 2 are integrated and oscillated with the position B4R as a fulcrum, and at the same time, the objective lens 1 is oscillated with respect to the prism 2 with the position A1R as a fulcrum. It is possible to tilt the photographing optical axis of the reflection optical system at a desired tilt angle while making the inclination of the incident optical axis 2 coincide with the inclination of the optical axis of the objective lens 1.

  Next, a reflection optical system assembly in which the reflection optical system and the tilt driving mechanism thereof are incorporated will be described with reference to FIGS. 1 to 3, 6 and 7.

  As shown in FIGS. 1 and 3, the objective lens 1 is incorporated and held in an objective lens holder 7. In the objective lens holder 7, four engagement holes 7a and two engagement holes 7b are formed. The prism 2 is incorporated and held in the prism holder 8. The prism holder 8 is formed with two cam grooves 8a, two fitting holes 8b, and two fitting holes 8c. A part of the lens group 5 is incorporated and held in the lens holder 9. The lens holder 9 has four screw holes 9a.

  A tilt base plate 10 is attached to the lens holder 9. The tilt base plate 10 has two holes 10a, two holes 10b, four holes 10c, and two cam grooves 10d. A screw (not shown) is inserted into each hole 10 c of the tilt base plate 10, and each screw is screwed into a corresponding screw hole 9 a of the lens holder 9. Thereby, the tilt base plate 10 is fixed to the lens holder 9. The tilt base plate 10 supports the objective lens holder 7 and the prism holder 8 in a swingable manner, and supports the tilt drive lever 11 in a rotatable manner.

  The tilt drive lever 11 is provided with two holes 11a, one engaged groove 11b, two objective lens holder drive cam grooves 11c, and a prism unit drive cam groove 11d. Each hole portion 11 a is disposed at a position that becomes the rotation center of the tilt drive lever 11. A corresponding tilt drive lever support pin 12 is inserted into each hole portion 11 a of the tilt drive lever 11, and each tilt drive lever support pin 12 is press-fitted into a corresponding hole portion 10 a of the tilt base plate 10. Thereby, the tilt drive lever 11 is supported rotatably with respect to the tilt base plate 10.

  A driving force from the reduction gear unit is transmitted to the engaged groove portion 11b. The reduction gear unit includes a stepping motor 14, and the stepping motor 14 is fixed to the tilt gear base plate 13. A pinion gear 15 is fixed to the output shaft 14 a of the stepping motor 14. The first reduction gear 16 is engaged with the pinion gear 15, the second reduction gear 17 is engaged with the first reduction gear 16, and the rotation of the stepping motor 14 is rotated via the pinion gear 15. 16 and transmitted to the second reduction gear 17. Each of the first reduction gear 16 and the second reduction gear 17 is rotatably supported on the support shafts 13 a and 13 b of the tilt gear base plate 13. The second reduction gear 17 is integrally formed with an engaging protrusion 17 a that engages with the engaged groove 11 b of the tilt drive lever 11. When the engaging projection 17a is rotated along with the rotation of the second reduction gear 17, the tilt drive lever 11 is moved around the tilt drive lever support pin 12 by the engaged groove portion 11b engaged with the engagement projection 17a. Are rotationally driven angularly.

  Two screw holes 13 c are formed in the tilt gear base plate 13. A tilt gear presser 18 is fixed to the tilt gear base plate 13, and the tilt gear presser 18 supports the support shafts 13 a and 13 b in cooperation with the tilt gear base plate 13. Screws (not shown) inserted through the respective holes 10b of the tilt base plate 10 are screwed into the respective screw holes 13c of the tilt gear base plate 13, whereby the tilt gear base plate 13 is engaged with the tilt base plate 10. It is fixed (see FIG. 2).

  As described above, the reduction gear unit including the tilt gear base plate 13, the stepping motor 14, the pinion gear 15, the first reduction gear 16, the second reduction gear 17, the tilt gear presser 18 and the like is disposed on the back side of the prism 2. . Thereby, the space which arises in the back side of the prism 2 can be utilized effectively, and the enlargement of a mechanism can be prevented.

  Cam pins 19 are press-fitted into the respective engagement holes 7a of the objective lens holder 7, and the cam pins 19 are slidably supported in the cam grooves 8a of the prism holder 8 (see FIG. 6). Each cam groove 8a has a cam shape that draws a trajectory in which the objective lens holder 7, that is, the objective lens 1, swings about the position A1R as described above. An objective lens holder drive pin 20 is press-fitted into each engagement hole 7 b of the objective lens holder 7. Each objective lens holder drive pin 20 is inserted into two cam grooves 8a formed in the prism holder 8 in the same manner as the cam pin 19 (see FIG. 6). Here, each objective lens holder driving pin 20 is formed with a driven shaft portion 20a, and each driven shaft portion 20a has a smaller diameter than the cam pin 19 so as not to interfere with the corresponding cam groove 8a. (See FIG. 6). Furthermore, the driven shaft portion 20a is slidably engaged with the objective lens holder drive cam groove 11c of the tilt drive lever 11, as will be described later.

  With such a configuration, the objective lens holder 7 can swing along each cam groove 8 a of the prism holder 8. That is, the objective lens 1 can swing with respect to the prism 2 with the position A1R as a fulcrum.

  Cam pins 21 are press-fitted into the respective fitting holes 8 b of the prism holder 8. Each cam pin 21 is slidably supported in a corresponding cam groove 10d of the tilt base plate 10 (see FIG. 1). Cam pins 22 are press-fitted into the respective fitting holes 8 c of the prism holder 8. Each cam pin 22 is formed with an engaging portion 22a, and the engaging portion 22a is slidably supported with the corresponding cam groove 10d of the tilt base plate 10. Each cam pin 22 is formed with a driven portion 22b having a diameter smaller than that of the engaging portion 22a. Each driven portion 22b is slidably engaged with the prism unit drive cam groove 11d of the tilt drive lever 11. (See FIG. 1). Here, the cam groove 10d of the tilt base plate 10 has a cam shape that draws a locus in which the objective lens holder 7 and the prism holder 8 integrally swing with the position B4R as a fulcrum.

  As described above, the objective lens 1 and the prism 2 can be swung integrally with the position B4R as a fulcrum, and at the same time, the objective lens 1 can be swung with respect to the prism 2 with the position A1R as a fulcrum. That is, the prism 2 and the objective lens 1 are integrally swung by the action of the objective lens holder driving cam groove 11c, the prism unit driving cam groove 11d, the cam groove 8a of the prism holder 8, and the cam groove 10d of the tilt base plate 10, respectively. At the same time, since the objective lens 1 is further swung with respect to the prism 2, the inclination of the optical axis of the objective lens 1 with respect to the optical axis A can be matched with the inclination of the incident optical axis of the prism 2.

  As described above, the tilt drive lever 11 is rotatably supported with respect to the tilt base plate 10 by the tilt drive lever support pin 12, and is rotationally driven around the tilt drive lever support pin 12 by the reduction gear unit (see FIG. (Refer to Fig. 2. In this figure, the tilt gear holder 18 is not shown). Specifically, when the stepping motor 14 is driven to rotate in a predetermined direction, for example, clockwise, the rotation of the stepping motor 14 is transmitted to the second reduction gear 17 via the pinion gear 15 and the first reduction gear 16. As the second reduction gear 17 rotates, the engagement protrusion 17a of the second reduction gear 17 rotates clockwise while engaging with the engagement groove 11b of the tilt drive lever 11, so that the tilt drive lever 11 is Then, it rotates angularly clockwise around the tilt drive lever support pin 12 (see FIG. 7).

  As the tilt drive lever 11 rotates, the objective lens holder 7 is swung clockwise along the objective lens holder drive cam groove 11c, and the prism holder 8 is swung clockwise along the prism unit drive cam groove 11d. That is, the objective lens 1 and the prism 2 are swung clockwise with the position B4R as a fulcrum. At the same time, the objective lens holder 7 is swung clockwise along the cam groove 8 a of the prism holder 8. That is, the objective lens 1 is swung clockwise with respect to the prism 2 with the position A1R as a fulcrum. Thereby, the photographing optical axis of the reflection optical system can be tilted upward.

  Conversely, if the stepping motor 14 is driven to rotate counterclockwise, the photographing optical axis of the reflective optical system can be tilted downward.

  Thus, according to the present embodiment, the photographing optical axis of the reflective optical system can be tilted to a desired angle by swinging the objective lens 1 and the prism 2.

  The present invention is not limited to the above-described embodiment, and may take any form as long as it does not depart from the principle of the present invention.

It is the perspective view which looked at the reflective optical system assembly incorporating the tilt drive mechanism which concerns on one embodiment of this invention from the front side. It is the perspective view seen from the back side of the reflective optical system assembly of FIG. It is a disassembled perspective view of the reflective optical system assembly of FIG. It is a figure which shows typically the structure of the reflective optical system in the reflective optical system assembly of FIG. FIG. 5 is a diagram schematically showing a change in a tilt direction of a photographing optical axis when the prism 2 of FIG. 4 is rotated. FIG. 2 is a perspective view showing a state where an objective lens holder 7 of the reflective optical system assembly of FIG. 1 is supported by a prism holder 8 by a cam pin 19. It is the perspective view which looked at the tilt state of the reflective optical system assembly of FIG. 1 from the back side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Objective lens 2 Prism 7 Objective lens holder 8 Prism holder 8a Cam groove 10 Tilt ground plate 11 Tilt drive lever 11c Objective lens holder drive cam groove 11d Prism unit drive cam groove 12 Tilt drive lever support pin 13 Tilt gear base plate 14 Stepping motor 18 Cam pin 20 Objective lens holder drive pin 21, 22 Cam pin

Claims (9)

An optical element having a first optical axis and a reflective optical element disposed behind the optical element, and the reflective optical element allows light emitted from the optical element along the first optical axis to be emitted by the reflective optical element; In a tilt drive mechanism of an optical system configured to guide in a direction along a second optical axis perpendicular to the first optical axis,
First swinging means for swinging the optical element and the reflective optical element together with a first position as a fulcrum;
A tilt driving mechanism for an optical system, comprising: a second swinging unit configured to swing the optical element with respect to the reflective optical element with a second position as a fulcrum.   2. The tilt drive mechanism for an optical system according to claim 1, wherein the first position is a fixed position coaxial with the second optical axis.   3. The tilt drive mechanism for an optical system according to claim 1, wherein the second position is a position coaxial with the first optical axis.   The second oscillating means is a photographing optical axis in which the first optical axis of the optical element when the first oscillating means is oscillated integrally with the reflective optical element is preset. 4. The optical element according to claim 1, wherein the optical element is swung with respect to the reflective optical element using the second position as a fulcrum so as to form a predetermined angle with respect to the reflective optical element. Optical system tilt drive mechanism. The optical system includes a reflective optical element holding member that holds the reflective optical element, and a ground plane for supporting the reflective optical element holding member,
The first swinging means includes a cam follower provided on the reflective optical element holding member, a cam groove provided on the base plate and engaged with the cam follower, and a first drive means for driving the cam follower. The tilt drive mechanism for an optical system according to claim 1, wherein the tilt drive mechanism is an optical system. The optical system includes an optical element holding member that is supported by the reflective optical element holding member and holds the optical element;
The second swinging means includes a cam follower provided on the optical element holding member, a cam groove provided on the reflective optical element holding member and engaged with the cam follower, and a second driving the cam follower. 6. The tilt drive mechanism for an optical system according to claim 5, further comprising a drive unit.   The first drive means is a drive means that also serves as the second drive means, and includes a drive member that is rotatably supported by the base plate, and a drive source that rotationally drives the drive member. The tilt drive mechanism for an optical system according to claim 6.   8. The tilt drive mechanism for an optical system according to claim 7, wherein the drive source of the first drive means is disposed on the back side of the reflective optical element.   An imaging apparatus comprising the tilt drive mechanism of the optical system according to any one of claims 1 to 8.

Images