JPS63256919A - Interlacing optical mechanism - Google Patents

Abstract

PURPOSE:To reduce the size of an image pickup device by forming the reflecting surfaces of a rotary polygon mirror so that light is reflected inside, and providing a fixed reflecting mirror in the internal rotary space of the rotary polygon mirror. CONSTITUTION:This optical mechanism consists of the rotary polygon mirror 13 constituted by supporting at least one couple of reflecting mirrors 15 having mirror surfaces in parallel to a rotary shaft 14 at positions axially symmetrically about a rotary member 9 fixed on the rotary shaft 14 and the fixed reflecting mirror 16 arranged in the space encircled with the minimum rotational track 17 of the rotary polygon mirror 13 while having a mirror surface to the rotary shaft 14. Incident light from an incidence opening 2 is therefore reflected by the rotary polygon mirror 13 through its reflecting mirror 15 so as to approach the rotary shaft 14, and the distance l between the center of the rotary shaft 14 and the optical axis of an image forming lens 7, i.e. optical axis of incidence on a linear multi-element photodetector 8 can be made shorter than before. Consequently, a housing 1 for storing device is reducible in size.

Description

[Detailed Description of the Invention] [Summary] The present invention reflects inward the reflecting surface of a rotating polygon mirror, which conventionally reflected outward, in interlaced scanning in an imaging device using a linear multi-element photodetector. By installing a fixed reflector in the internal rotation space of the rotating polygon mirror, the distance between the rotation axis of the rotating polygon mirror and the incident optical axis of the photodetector can be reduced, making the imaging device more compact. This is what I did.

[Industrial application field]

The present invention relates to an imaging device that performs interlaced scanning, and particularly to an interlaced optical mechanism.

There is a strong demand for miniaturization of optical mechanisms used in imaging devices that perform interlaced scanning, such as infrared imaging devices.

In order to achieve this, it is necessary to downsize each component and at the same time
A scanning method is needed that allows for compact arrangement of each component.

[Conventional technology]

FIG. 4 shows a plan layout of a conventional imaging device, and FIG. 5 shows a modified plan layout of FIG. In Fig. 4, ■ is the housing of the imaging device, 2 is the entrance for light from the subject, 3 is a rotating polygon mirror (a four-sided mirror in this example), 4 is the rotation axis of the rotating polygon mirror 3, and 5 is a rotating polygon. Each reflecting mirror of the mirror 3, 6 is a fixed reflecting mirror separated from the rotating polygon mirror, 7 is an imaging lens, 8 is a linear multi-element photodetector, and β is the optical axis of the imaging lens 7 (i.e., a linear multi-element photodetector). The distance between the center point of the rotation axis 4 and the optical axis of incidence on the element photodetector 8 is shown.

As shown in the figure, the incident light from the object that enters from the entrance 2 is reflected on the reflecting mirror 5 made outside the rotating polygon mirror 3, further reflected by the fixed reflecting mirror 6, and then reflected by the linear polygon lens 7 through the imaging lens 7. An image is formed on the element photodetector 8. By rotating the rotating polygon mirror 3 around its rotation axis 4, it is a mechanism that can scan in a direction perpendicular to the rotation axis 4.

[Problem that the invention seeks to solve]

In the conventional system, the reflective surface of the rotating polygon mirror 3 is provided outside the rotating body, so considering the rotation space of the rotating polygon mirror 3 and the deflection of the light beam by each component,
The position of the fixed reflecting mirror 6 is outside the maximum rotation radius of the rotating polygon mirror 3, and the distance l between the center of the rotation axis 4 and the optical axis of the imaging lens 7 is equal to the maximum rotation radius of the rotating polygon mirror 3 and the radius of the light beam. It will be longer than the value added.

Since the external dimensions of the linear multi-element photodetector 8 are limited, it is necessary to reduce the distance β in order to downsize the device. In order to reduce this distance e, it is necessary to add a plurality of fixed reflecting mirrors 6 to form a detour optical path as shown in FIG. is required,
In addition, a disadvantage is that the performance of the reflection weight decreases.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide an interlaced optical mechanism capable of reducing the distance l between the center of the rotating shaft 4 and the optical axis of the imaging lens 7.

[Means for solving problems]

As shown in the principle diagram of FIG. 1, the interlace optical mechanism of the present invention has a reflecting mirror 1 having a mirror surface parallel to the rotating shaft 14 at an axially symmetrical position of the rotating member 9 fixed to the rotating shaft 14.
A rotary polygon mirror 13 is arranged with a mirror surface parallel to the rotation axis 14 in a space surrounded by a minimum rotation locus 17 of the rotary polygon mirror 13 and a rotating polygon mirror 13 formed by supporting at least one pair of polygon mirrors 5 so as to face each other in parallel. It is composed of a fixed reflecting mirror 16.

[Effect]

In the rotating polygon mirror 13 of the present invention, the incident light from the entrance 2 is reflected by the reflecting mirror 15 in a direction approaching the rotation axis 14, and as a result, the center of the rotation axis 14 and the optical axis of the imaging lens 7 (i.e., a straight line type multi-element photodetector 8)
The distance l between the device and the device can be shortened compared to the conventional case
This makes it easier to downsize.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Note that, in order to make the explanation of the configuration and operation easier to understand, the same parts are given the same reference numerals throughout all the figures, and repeated explanation thereof will be omitted.

FIG. 2 is a plan layout view of an interlace optical mechanism according to an embodiment of the present invention, and FIG. 3 is a perspective view of the rotating polygon mirror and fixed reflecting mirror shown in FIG. 2. Hereinafter, FIG. 2 will be explained with reference to FIG.

Reference numeral 24 denotes a rotation shaft, which is connected to a rotation drive unit (not shown) and rotates in the direction of arrow P at a constant rotation speed synchronized with the scanning period. Reference numeral 10 denotes a rotating member fixed to the rotating shaft 24, and reflective mirrors 25a and 25b having mirror surfaces parallel to the rotating shaft 24 are mounted parallel to each other at symmetrical positions on the rotating member 10 with respect to the rotating shaft 24. A rotating polygon mirror 23 with two mirror surfaces is supported in pairs so as to face each other.

The interface of this embodiment is formed from the rotating polygon mirror 23 and a fixed reflecting mirror 26 which is disposed facing each other with mirror surfaces parallel to the rotation axis 24 in a space surrounded by the minimum rotation locus 27 of the rotating polygon mirror 23. Lace optics are configured. In addition, 2
8 is a fixed base for supporting the fixed reflecting mirror 26.

In FIG. 2, the incident light from the object that enters through the entrance opening 2 is reflected by the reflecting mirror 25a or 25b of the rotating polygon mirror 23 and the fixed reflecting mirror 26, and then passes through the imaging lens 7 to linear multi-element light detection. The image is formed on the device 8.

Since the light beam reflected by the reflecting mirror 25a or 25b of the rotating polygon mirror 23 is reflected in a direction approaching the rotation axis 24, the distance l can be made smaller than in the conventional example. By rotating this rotating polygon mirror 23 around a rotation shaft 24, scanning can be performed twice per rotation.

The miniaturization effect when the rotating polygon mirror has a two-sided configuration is that the width of the device is L, and the width M of the linear multi-element photodetector 8 is 781 mm.
TIII+, the reduction ratio is approximately 0.7 when the conventional maximum rotation radius is 30 mm and the maximum rotation radius in Figure 2 is 44 mm.
Miniaturization of about 5L can be achieved.

〔Effect of the invention〕

As explained in detail above, according to the interlaced optical mechanism of the present invention, the distance l between the center position of the rotating polygon mirror and the incident optical axis of the linear multi-element photodetector is reduced by the increase in the number of reflections, resulting in a decrease in performance. This has the effect of reducing the size of the device housing.

[Brief explanation of drawings]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a plan view of an interlace optical mechanism according to an embodiment of the present invention, Fig. 3 is a perspective view of the rotating polygon mirror and fixed reflecting mirror shown in Fig. 2, and Fig. 4 The figure shows a plan layout of a conventional imaging device, and FIG. 5 shows a modified plan layout of FIG. 4. In FIG. 1, 9 is a rotating member, 13 is a rotating polygon mirror, 1
4 is a rotating shaft, 15 is a reflecting mirror, and 16 is a fixed reflecting mirror.

Claims (1)

[Claims] Reflecting mirrors (15) having mirror surfaces parallel to the rotation axis (14) are placed at axially symmetrical positions of the rotation member (9) fixed to the rotation axis (14) so as to face each other in parallel. at least one pair of rotating polygon mirrors (13) supported by the rotary polygon mirror (13); and a mirror surface parallel to the rotation axis (14) arranged in a space surrounded by the minimum rotation locus (17) of the rotating polygon mirror (13). An interlaced optical mechanism characterized in that it is comprised of a fixed reflecting mirror (16).