JPH0239119A - Rotary polygon mirror driving device - Google Patents

Abstract

PURPOSE:To facilitate countermeasure even in using a general bearing and to easily control the rotation of a driving motor by driving a polygon mirror so that it is integrally rotated with the rotor of a 2nd rotating motor whose stator is fixed to the rotor of a 1st rotating motor. CONSTITUTION:A fly-wheel 3 is fixed to one end of the rotating shaft 2 of the 1st rotating motor 1 and the stator 5 of the 2nd rotating motor 4 is fixed to the other end thereof. The center shaft 6 of the stator 5 is integrally constituted with the rotating shaft 2 of the 1st rotating motor 1 and the peripheral wall of a rotor housing 10 in the 2nd rotating motor 4 is formed, for example, in a hexahedral polygon mirror 14. Considering horizontal scanning in an NTSC system by means of the hexahedral polygon mirror, high-speed rotation is needed in the case of driving the polygon mirror with a single motor. However, the speed of rotation of the 1st and the 2nd rotating motors 1 and 4 can be set extremely low in the title device. Thus, the general bearing can be used because of the low-speed rotation and the rotation of the respective motors can be easily controlled.

Description

TECHNICAL FIELD The present invention relates to a rotating polygon mirror driving device, and more particularly to a rotating polygon mirror driving device suitable for use in a high-speed laser scanning system such as a laser projector.

Background technology An example of the configuration of a high-speed laser scanning system is shown in FIG. 2.

In this figure, a laser beam optically modulated based on a video signal passes through a first cylindrical lens 21 for correcting pitch unevenness of scanning lines and enters the mirror surface of a polygon mirror 22 having, for example, a 25-sided shape. The polygon mirror 22 is used for horizontal deflection, and is driven to rotate at high speed by a drive motor 23. The laser beam horizontally deflected by the polygon mirror 22 passes through a first relay lens 24 for two-dimensional deflection, a second cylindrical lens 25 for correcting pitch unevenness of the scanning line, and a second relay lens 26 for two-dimensional deflection. Thereafter, the light enters a galvanometer mirror 27 for vertical deflection. The laser beam vertically deflected by the galvanometer mirror 27 is imaged by an imaging lens 28 on a screen (not shown).

In such a high-speed laser scanning system, in the case of NTSC horizontal scanning, the horizontal scanning frequency is 15.75 [K11
z] must be scanned at 945,000 [c, I), m,]. Therefore, even if a 25-sided polygon mirror 22 is used, for example, 37,800 [r, p, m,
] It is necessary to rotate the polygon mirror 22 at an extremely high speed.

Therefore, a very special bearing such as a dynamic pressure air bearing is required as a bearing for the drive motor 23, and it is also difficult to control the rotation of the motor itself. It is also possible to lower the rotation speed of the drive motor 23 by using a speed increasing mechanism, but if the speed increasing mechanism is configured with a combination of gears, for example,
A new problem arises in that negative effects such as jitter must be removed.

Summary of the Invention The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a rotating polygon mirror drive device that can be used with general bearings and can easily control the rotation of the drive motor. .

In the rotating polygon mirror drive device according to the present invention, the polygon mirror is integrally driven to rotate by the rotor of the second rotating motor, the stator of which is fixed to the rotor of the first rotating motor.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In FIG. 1 showing an embodiment of the present invention, a flywheel 3 is fixed to one end of a rotating shaft 2 of a first rotating motor 1, and a stator 5 of a second rotating motor 4 is fixed to the other end. ing. The flywheel 3 is a second rotating motor 4
This was provided to avoid the influence of speed control. In the second rotary motor 4, the stator 5 is composed of a central shaft 6 and an armature coil 7 fixed to the shaft 6, and a rotor 9 is rotatably provided with respect to the central shaft 6 via a bearing 8. It is composed of a rotor 1 housing 10 and a rotor magnet 11. The central axis 6 of the stator 5 is arranged, for example, in one body with the rotation axis 2 of the first rotary motor 1, and the armature coil 7 includes, for example, slimp rings, 2a, 12b, and brushes 13.
A power supply voltage is applied by a power supply means consisting of a and 13b. In addition, the second rotary motor 4
The peripheral wall of the rotor housing 10 is, for example, a hexahedral polygon mirror 14.

Here, when the rotating polygon mirror drive device according to the present invention having such a configuration is applied to a high-speed laser scanning system, for example, considering horizontal scanning in the NTSC system using a hexahedral polygon mirror, it is difficult to use a single motor as in the past. 15 in drive
7.500 [r, p, m,] high speed rotation is required (even in the case of a 25-hedral polygon mirror, the rotation speed is 37,800 [r, p, m,]). According to, for example, the number of rotations of the first rotating motor 1 is set to 450
, Ko, the number of rotations of the second rotary motor 4 is set to 350 [r, p,
By setting the polygon mirror 14 to 157.5
This means that it can be rotated at a rotational speed of 00 [r, p, +n,]. Suna 4cchi, 1st. The rotation speed of the second rotary motor 1.4 can be set extremely low.

According to this, 1st. General bearings such as oil-less metal or ball bearings can be used as the bearings for the second rotary motors 1 and 4, and the low-speed rotation makes it easy to control the rotation of each motor, making high-speed laser scanning extremely easy. This means that it can be realized.

By the way, when the polygon mirror 14 is a heptahedron, the number of rotations of the first rotary motor 1 is set to 450 [r, p, m,
The rotation speed of the rotating motor 4 is 300 [r, p, m, co,
In the case of a pentahedron, set the rotation speed of the first rotary motor 1 to 450 [r, p, Ill, ko, and the rotation speed of the second rotary motor 4 to 420 [r, p, m, ]. Good.

In addition, in the above embodiment, a case has been described in which the peripheral wall of the rotor housing 10 is integrally configured as the polygon mirror 14, but it does not necessarily have to be integral, and in short, the polygon mirror 14 or the second rotating motor Any configuration that can rotate integrally with the rotor 9 of No. 4 is sufficient.

As described in detail, in the rotating polygon mirror driving device according to the present invention, the polygon mirror is integrally rotated by the rotor of the second rotating motor, the stator of which is fixed to the rotor of the first rotating motor. Due to the drive configuration,
Since the rotation speed of each motor can be set to a low value, general bearings can be used as bearings for each motor, and rotation control of each motor is easy, and high-speed laser scanning can be easily realized.

[Brief explanation of the drawing]

FIG. 1 is a side view including a partial cross section showing an embodiment of the present invention, and FIG. 2 is a configuration diagram showing an example of a high-speed laser scanning system. Explanation of symbols of main parts 1...First rotating motor 3...Flywheel 4...Second rotating motor 5...Stator 9...・・・・・・
Rotor 14.22... Polygon mirror applicant Pioneer Corporation

Claims (2)

[Claims] (1) A first rotating motor, a second rotating motor having a stator fixed to the rotor of the first rotating motor, and a polygon mirror that rotates integrally with the rotor of the second rotating motor. A rotating polygon mirror drive device comprising: (2) The rotating polygon mirror drive device according to claim 1, further comprising a flywheel fixed to the rotor of the first rotating motor.