JPS5852563B2 - Rotating scanner for infrared imager - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a rotary scanner for an infrared imaging device using a mechanical scanning device.

FIG. 1 shows the principle of an infrared imaging device using a mechanical scanning device.

In Figure 1, 1 is a high-speed rotating motor, 2 is a polyhedral reflector, 3 is a telescope, 4 is a vibrating mirror, 5 is a condensing lens, 6 is a detector, I is an amplifier, 8 is a sweep signal generator, and 9 is a display. It is a vessel.

The incident infrared rays pass through the telescope 3 and are reflected by the polyhedral reflecting mirror 2 and the vibrating mirror 4, and then are condensed by the condensing lens 5 and enter the detector 6.

During this time, the field of view seen from the detector 6 is two-dimensionally scanned by the rotation of the polyhedral reflecting mirror 20 and the vibration of the vibrating mirror 4.

Therefore, when the electric signal converted by the detector 6 is amplified by the amplifier 7 and input to the display 9 which is swept by the sweep signal generator 8, an infrared image can be displayed.

In order to obtain a good image in real time at this time, the polyhedral reflecting mirror 20 must be rotated several hundred times per minute.

FIG. 2 shows the configuration of a conventional rotary scanner consisting of a high-speed rotary motor 1 and a polyhedral reflecting mirror 2.

As shown in FIG. 2, the conventional rotary scanner has a configuration in which a high-speed rotary motor 1 and a polyhedral reflecting mirror 2 are connected by extending the axis of the motor.

On the other hand, the reflective surface of the polyhedral reflective mirror 2 needs to ensure a constant reflective area for the required scanning angle.

Further, the number of surfaces of the polyhedral reflecting mirror 20 is determined in such a manner that the product of the motor rotation speed and the number of surfaces is a constant number with respect to the required number of scanning lines.

Therefore, the polyhedral reflecting mirror 2 inevitably has a constant volume.

In the configuration of a conventional rotary scanner as shown in Fig. 2, the inertia of the polyhedral reflector 2 and the rotor of the motor are inevitably added, which increases the power required for the motor. Despite the rotation, it is supported on a so-called cantilever, making it difficult to maintain rotational precision for a long period of time, increasing the dimension in the direction of the rotating shaft, making the device larger, and requiring a complicated shape to add a dust cover. there were.

In order to eliminate these drawbacks, the present invention attempts to utilize the surface of the rotor of an outer rotor motor as a polyhedral reflecting mirror 2, and will be described in detail below with reference to the drawings.

Figures 3a and 3b show embodiments of the invention, with Figure 3a showing a perspective view and Figure 3 a sectional view.

In FIG. 3, 10 is a rotor magnetic body, 11 is a stator magnetic body, 12 is a stator coil, 13 is a ball bearing, 1
4 is a stator mounting bracket, and 15 is a rotor frame.

The motor in Figure 3 is a so-called outer rotor motor.
The center part is the stator, and the rotor is located on the outside and rotates via ball bearings 13.The principle of rotation is that it is used in devices such as gyros that take a large rotational moment and require high speed rotation. This is publicly known.

However, in order to prevent deterioration of life due to swelling, the outer rotor motor has a sealed structure, such as by providing a case on the outside of the rotor and filling it with nitrogen gas.

As is well known, infrared rays do not pass through glass.
Furthermore, if there is an object with a different temperature near the infrared light path, it will generate infrared rays and become a noise source.

Therefore, a case that partially has a glass window cannot be used in an infrared imaging device.

The present invention provides a rotary scanner for an infrared imaging device, in which the surface of the rotor of an outer rotor motor is molded to form a polyhedral reflecting mirror 2, and a portion corresponding to the infrared light path is exposed, as shown in FIG. That is.

By molding the surface of the rotor to form a polyhedral reflecting mirror 2 as shown in FIG. 3, the overall inertia of the rotary scanner is at least 2 times higher than that of the conventional one shown in FIG.
Since the polyhedral reflecting mirror 2 shown in the figure is made smaller by the volume corresponding to the rotor of the motor, the rise time and power at startup can be reduced.

In addition, since the rotor necessarily has a double bearing structure, it is easier to balance than the one in Figure 2, and it can operate stably for a long period of time, and the overall volume is approximately the same as that of the motor itself. Since they can be matched, they can be made smaller and lighter.

Note that by exposing the infrared light path, the attenuation of input and output infrared light can be made zero, and the rotor magnetic body 10,
The heat generated by the core loss of the stator magnetic body 11 and the stator coil 120 joule loss can also be radiated to the mounting base through heat transfer through the case, thereby preventing harmful radiation to the infrared optical path.

Prevention of dust on the surfaces of the ball bearing 13 and the polyhedral reflecting mirror 2 can be achieved by covering the infrared light path from the telescope 3 to the condensing lens 5 in FIG. 1 with an integral case.

Since the rotary scanner is small and simple in shape, the shape of the case is also simple.

Although the case where the surface of the rotor of the outer rotor motor is molded into the polyhedral reflecting mirror 2 has been described above, methods such as attaching the polyhedral reflecting mirror 2 by fitting or using screws may also be considered.

As described above, the rotary scanner for an infrared imaging device according to the present invention not only makes the device smaller and lighter, consumes less power, and stabilizes rotation accuracy over a long period of time, but also allows the entire infrared path to be covered with a simple case. Rotational noise generated by high-speed rotation can also be reduced.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram of an infrared imaging device using a mechanical scanning device, Fig. 2 is a configuration diagram of a conventional rotary scanner for an infrared imaging device, and Fig. 3 is a perspective view and a sectional view of an embodiment of the present invention. It is. In the figure, 1 is a high-speed rotating motor, 2 is a polyhedral reflector, 10 is a rotor magnetic body, 11 is a stator magnetic body, 12 is a stator coil, 13 is a ball bearing, 14 is a stator mounting bracket, 1
5 is a rotor frame. In the drawings, the same or corresponding parts are designated by the same reference numerals.

Claims (1)

[Claims] 1 Outer Rotor Motor
1. A rotary scanner for an infrared imaging device, characterized in that the surface of a rotor of a rotor (tor) is formed into a polyhedral reflecting mirror, and a part of the rotating part corresponding to an infrared optical path is exposed.