JPH08220207A - Optical apparatus - Google Patents

Abstract

PURPOSE: To provide an optical apparatus having an inexpensive method to rotate a lens and a mirror at a rate of two to one. CONSTITUTION: A mirror 8 is constituted so as to simultaneously rotate by 1/2 in the same direction on the same axis together with a holder 2 when the holder 2 is rotated by a motor 6 through a first pulley 17 fixed to the holder 2, a second pulley 18 fixed to the mirror 8, a third pulley 21 and a fourth pulley 22 fixed to a shaft 19, a first belt extended round the first pulley 17 and the third pulley 21 and a second belt extended round the second pulley 18 and the fourth pulley. Therefore, since a motor to rotate the mirror, a resolver, a power amplifier and a control circuit become unnecessary, an inexpensive and highly reliable optical apparatus can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device mounted on an aircraft, a ship or the like and used for obtaining a visible or infrared image of a target object in an arbitrary direction by remote scanning.

[0002]

2. Description of the Related Art FIG. 7 is a view showing a conventional optical device,
FIG. 8 is a cross-sectional view of FIG. 7 cut along AA. In the figure, 1 is a lens, and 2 is a holder for holding the lens 1, which is rotatably supported by a frame 5 via bearings 3 and 4.
6 is a motor for rotating the holder 2, and 7 is a resolver for reading the rotation angle. A mirror 8 is rotatably supported by the frame 5 via bearings 9 and 10.
11 is a motor for rotating the mirror 8,
Is a resolver. The frame 5 is rotatably supported by the fixed portion 15 via bearings 13 and 14. In the figure, a motor and a resolver for rotating the frame 5 are omitted for simplicity. Reference numeral 16 is an image sensor.

The light incident from B is condensed by the lens 1 and is bent by the mirror 8 at 90 ° to form an image on the image pickup device 16. An image of the target object in an arbitrary direction can be obtained by rotating the frame 5 around the C axis and rotating the holder 2 and the lens 1 around the D axis which is on the frame 5 and is orthogonal to the C axis. At this time, the mirror 8 moves in the same direction as the lens 1 around the same D axis as the lens 1.
It is necessary to rotate by 1/2 angle. Therefore, the conventional optical equipment uses two systems of power amplifiers and control circuits. That is, in response to the angle command of the controller, the power amplifier and the control circuit of the first system drive and control the motor 6 by using the feedback signal of the resolver 7, and the command value is 1/2 of the angle command issued from the controller. On the other hand, the power amplifier and the control circuit of the second system drive and control the motor 11 using the feedback signal of the resolver 12. Thus, the mirror 8 and the lens 1 are moved by the two independent circuits.

[0004]

Since the conventional optical device is constructed as described above, two systems of motors for lens and mirror, a resolver and a motor drive for changing the visual axis around the D axis are used. However, there is a problem that the power amplifier and the control circuit are required, and the cost becomes very expensive. From the viewpoint of visual axis control, in addition to static errors such as linear errors of the resolver, since two independent systems are used, dynamic errors are added for two systems and without synchronization, resulting in There was a problem that the visual axis control accuracy was deteriorated.

The present invention has been made to solve the above problems, and an object thereof is to obtain an optical device which is inexpensive and has excellent visual axis control accuracy, and further facilitates manufacturing adjustment of the device. It also aims to improve performance and extend life.

[0006]

Embodiment 1 of the optical apparatus according to the present invention is one in which four pulleys and two belts move a mirror and a lens at an angle of 1 to 2.

In the second embodiment of the present invention, one part of the pulley is curved to make it easy to apply pretension to the belt.

In the third embodiment of the present invention, a parallel portion is provided between the inside of the curved beam and the hub portion so that the pretension can be easily controlled.

Further, the fourth embodiment of the present invention is such that the belt is hooked, the movable angle can be wide, and the bearing life is extended.

Further, the fifth embodiment of the present invention optimizes the diameter of the pulley to maximize the movable angle and minimize the bearing load.

[0011]

In the first embodiment of the present invention, the mirror is simultaneously moved by 1/2 by moving the lens, so that one system of the motor, the resolver, the power amplifier, and the control circuit is unnecessary.
Further, since one system is deleted, the factor of dynamic error is reduced and the accuracy is improved.

Further, in the second embodiment of the present invention, it is possible to easily apply pretension by releasing the external force after attaching the belt in a state in which the bending beam is applied with the external force and slightly opened.

Further, in the third embodiment of the present invention, an external force can be easily applied by providing parallel portions on the inside of the curved beam and the hub portion, and pretension can be easily controlled by controlling the dimension between the parallel portions.

Further, in the fourth embodiment of the present invention, the contact distance between the pulley and the belt is lengthened by hanging the belt, so that the movable angle can be widened and the resultant force of the pre-tension of the belt is reduced, so that the bearing load is increased. It is possible to reduce the bearing life and extend the bearing life.

Further, according to the fifth embodiment of the present invention, the movable angle can be maximized and the bearing load can be minimized by minimizing the clearance between the pulleys.

[0016]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of the optical device of the present invention, and FIG. 2 is a view showing only the pulley portion in FIG. In the figure, reference numeral 17 denotes a first pulley, which is fixed to the holder 2 so as not to move with screws or the like. A second pulley 18 is fixed to the mirror 8 so as not to move by a screw or the like. Reference numeral 19 denotes a shaft, which is rotatably supported by the frame 5 via a bearing 20. Reference numeral 21 is a third pulley, and 22 is a fourth pulley, which are fixed to the shaft 19 by screws or the like so as not to move. Two
3 is a first belt, the central portion of which is fixed to the first pulley 17 by a clamp 24, and both ends of which are clamps 25a,
It is fixed to the third pulley 21 by 25b. Similarly, the second belt 26 is fixed to the fourth pulley 22 at the central portion by the clamp 27 and to the second pulley 18 at both ends by the clamps 28a and 28b. When the motor 6 is driven to move the holder 2, the first pulley 17 is fixed to the holder 2 and rotates together. This is for example the direction of FIG. 2K. Since the first belt 23 is fixed to the first pulley 17 by the clamp 24, when the first pulley 17 rotates in the K direction, it is pulled in the L direction. First
The belt 23 of the third pulley 21 is clamped by the clamp 25a.
Since the first belt 23 moves in the L direction, the third pulley 21 rotates in the M direction. The rotation of the third pulley 21 is transmitted by the shaft 19 and the fourth pulley 22 also rotates in the M direction. At the same time, the second belt 26 fixed by the clamp 27 is pulled in the N direction,
The second pulley 18 fixed to the second belt 26 by 8b
Rotates in the P direction (the same as the rotation direction of the first pulley 17 and the K direction). Since the second pulley 18 is fixed to the mirror 8, the mirror also rotates in the P direction. At this time,

[0017]

[Equation 1]

Due to the dimensional relationship, when the holder 2 is rotated by the motor 6, the mirror 8 rotates in the same direction as the holder 2 by an angle of 1/2. Therefore, it becomes possible to move the visual axis around the D axis as in the conventional optical device. Since the mirror 8 is rotated by the force of the motor 6 in this manner, the motor 11 and the resolver 12 for moving the mirror 8 as in the conventional optical device are unnecessary. Therefore, the power amplifier control circuit for driving the motor 11 is also unnecessary. Further, the relative accuracy between the mirror 8 and the lens 2 is determined only by a static error such as the accuracy of the diameter of the pulley, and a high accuracy is achieved because no dynamic error is entered unlike the conventional optical device.

Example 2. In the first embodiment, exactly 1/2
In order to obtain the rotation angle of, the belts 23 and 26 are made of a material having high rigidity, for example, a belt made of steel, but on the other hand, it is necessary to devise to eliminate the slack of the belt. Generally, pre-tension is applied by pressing a roller supported by a spring against the belt, but this requires an extremely difficult adjustment in addition to increasing the number of parts. This embodiment provides a method of applying pretension easily. FIG. 3 is a view showing only the pulley portion.
In the figure, 29 is a notch provided in the second pulley 18, and for this reason, a curved beam 30 is formed in the second pulley 18.
Is formed.

When attaching the belt 26, first attach the central portion of the belt 26 to the fourth pulley 22 with the clamp 27,
Next, the clamp 28a is tightened while lightly pulling the belt 26 in the H direction in a state where the bending beam 30 is elastically deformed in the G direction by applying an external force. Finally, when the external force is released, bending beam 3
0 tries to return in the direction opposite to G, and at this time, the second belt 2
6 is pulled in the J direction and pretensioned. The force of the bending beam 30 to return in the direction opposite to G and the second belt 2
Since the curved beam 30 returns until it balances with the pretension of No. 6, it is understood that in order to control the pretension, it suffices to control the returning force of the curved beam 30. The force of the curved beam 30 to return is determined by the spring constant of the curved beam 30 (length, thickness of the beam portion,
It is a function of the Young's modulus of width, diameter and material, and is determined uniquely when these are determined) and the amount of deformation when elastically deformed in the G direction by first applying an external force. Therefore, the pretension of the second belt 26 can be controlled by controlling the amount of this elastic deformation. Further, although the curved beam 30 is deformed, the portion of θ in the drawing is not deformed, so that the precision of the pulley ratio can be secured if the diameter precision of this portion is made strictly. The movable angle in this case is 2θ about the axis of the second pulley 18.

Example 3. FIG. 4 is a diagram showing the second pulley. In the drawing, 31 is a hub portion of the second pulley 18, and a parallel portion 32 is formed between the hub portion 30 and the inside of the curved beam 30. By having the parallel portion 32 in this way, a tool for applying an external force can be easily applied and the amount of elastic deformation can be easily measured. For example, when the desired elastic deformation amount is Δa, the claw portion of the inner micrometer is put in the parallel portion 32, and the dimension a (the clearance dimension when not elastically deformed) is first measured, and then the inner micrometer Reading is a + △
If the screw of the inner micrometer is turned to a, the amount of elastic deformation of Δa can be accurately and easily obtained. By thus having the parallel portion 32, the adjustment work can be performed more easily and accurately.

Example 4. In the embodiment shown in FIG. 5, the second belt 26 is divided into two parts, which are hooked. FIG. 6 is a view of FIG. 5 viewed from the J direction. As compared with FIG. 3, firstly, there are advantages that the movable angle θ ′ can be set larger than θ and that the resultant force F ′ by the second pretension T is smaller than F. Since the resultant forces F'and F are applied to the bearing 20 as a radial force, they affect the life of the bearing, and the smaller the force, the longer the life.

In the case of FIG. 5, since the second pulley 18 and the fourth pulley 22 rotate in the opposite directions, if the first belt 23 as well as the second belt 26 is tucked, the third pulley 23 However, the first pulley 17 can rotate in the same direction as the second pulley 18, and the original purpose can be achieved.

Example 5. In Example 4

[0025]

[Equation 2]

By adopting the dimensional relationship, the movable angle θ'can be maximized and the bearing load F'can be minimized. Because in Fig. 5, the loss α of the movable angle is

[0027]

(Equation 3)

Since α is the minimum, that is, it becomes zero when the denominator and the numerator are equal. Bearing load F
´ is

[0029]

[Equation 4]

As described above, F'is minimum when α is minimum, that is, zero. However, in reality, due to the manufacturing error of the pulley, there is variation in the pulley diameter, and if the denominator and numerator of "Equation 3" are made equal, they will conflict with each other. Therefore, it is necessary to provide an appropriate clearance as in "Equation 2". The proper clearance mentioned here is a sum of the errors of the diameters of the first to fourth pulleys, the error of the pitch between the rotation axis of the holder and the rotation axis of the shaft, and the error of the belt thickness. By so doing, the maximum movable angle θ ′ and the minimum bearing load F ′ can be realized without conflict.

[0031]

Since the present invention is constructed as described above, it has the following effects.

Since the mirror can be rotated at the same time by rotating the lens with the pulley and the belt, one system motor, resolver, power amplifier, and control circuit are not required, and an inexpensive optical device can be realized and a dynamic error factor is generated. Since there is only one system, there is an effect that an optical device with excellent visual axis control accuracy can be realized.

Pre-tensioning can be easily applied by forming a part of the pulley into a curved beam shape.

By providing a parallel portion on the inside of the curved beam and the hub portion, pretension can be applied more easily and control can be performed more accurately.

By twisting the belt, a wide movable angle can be obtained, so that the performance is good, and since the bearing load can be reduced, a long-life optical device can be realized.

The dimensional relationship of "Equation 2" has the effect of maximizing the movable angle and minimizing the bearing load.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a pulley unit according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a pulley portion according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a pulley portion of Embodiment 3 of the present invention.

FIG. 5 is a diagram showing a pulley portion according to a fourth embodiment of the present invention.

FIG. 6 is a view of a pulley portion according to a fourth embodiment of the present invention as seen from below.

FIG. 7 is a diagram showing a conventional optical device.

FIG. 8 is a cross-sectional view showing a conventional optical device.

[Explanation of symbols]

1 lens, 2 holder, 3 bearing, 4 bearing, 5 frame, 6 motor, 7 resolver, 8 mirror, 9
Bearing, 10 bearing, 11 motor, 12 resolver, 1
3 bearings, 14 bearings, 15 fixed parts, 16 image sensor, 17 first pulley, 18 second pulley, 19
Shaft, 20 bearing, 21 third pulley, 22 fourth pulley, 23 first belt, 24 clamp, 2
5 clamps, 26 second belt, 27 clamps,
28 clamps, 29 notches, 30 curved beams, 31
Hub part, 32 parallel part.

Claims (5)

[Claims] 1. A lens for converging light, a holder for holding the lens, a first pulley attached to the holder, a mirror for changing the optical axis direction, and a second attachment for the mirror. A pulley, a frame that rotatably supports the holder and the mirror independently of each other coaxially,
A shaft rotatably attached to the frame about a parallel axis offset from the rotation axis of the mirror and the holder, a third pulley and a fourth pulley attached to the shaft, the first pulley and the third pulley. A first belt that is hung on the pulley, a second belt that is hung on the second pulley and the fourth pulley, and a motor that rotates the holder with respect to the frame. The optical device having a dimensional relationship that the product of the diameter of the pulley and the diameter of the fourth pulley is half the product of the diameter of the second pulley and the diameter of the third pulley. 2. The optical device according to claim 1, wherein one of the circumferential portions of the second pulley and the third pulley has a curved shape. 3. The optical apparatus according to claim 2, wherein the pulley has a curved inner side and a hub portion of the pulley having a parallel portion. 4. The optical apparatus according to claim 2, wherein the first belt and the second belt are both sewn. 5. The sum of the diameter of the first pulley and the diameter of the third pulley is the diameter of the second pulley and the diameter of the fourth pulley.
5. The optical device according to claim 4, wherein the optical device is equal to the sum of the diameters of the pulleys, and is equal to a value obtained by subtracting a clearance for making a belt thickness from the shaft pitch.