JPS61141417A - Scanner - Google Patents

Abstract

PURPOSE:To make possible the reduction in the size and noise of a scanner by providing a reflecting mirror of which the reflecting surfaces cross each other obliquely with the rotating axis of a rotary polyhedral mirror and which receives the incident luminous flux reflected by the rotary polyhedral mirror and matches approximately the optical axis of the luminous flux with the rotating axis to the scanner. CONSTITUTION:The rotary polyhedral mirror 11 has a conical recess which is opened on the incident side of the incident luminous flux B. The inside circumferential surface of the recess inclines about 45 deg. and the plural reflecting surfaces 12 are disposed at equal intervals along the circumferential direction thereof. The scanner reflects the incident luminous flux B mad incident on the rotary polyhedral mirror 11 at the surfaces 12, advances the flux toward the rotating axis A, reflects the flux by the reflecting surface 52 so as to match approximately the optical axis with the rotating axis A and to advance the flux toward a condensing system 3 and condenses the light toward the position of a line sensor 4. The incident luminous flux B is scanned in the direction (a) by the rotation of the mirror 11 in this stage. Since the mirror 11 is small-sized, the image pickup device using this scanner is smaller considerably in size than the conventional scanner while the scanner can pick up images in real time. There are no angular parts in the rotating direction on the inside and outside circumferential surfaces of the mirror 11 and therefore the breathing sound by the rotation is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scanning device, and particularly to the configuration of a scanning device forming a scanning optical system in an imaging device.

2. Description of the Related Art Line sensors formed of semiconductors have come to be used as optical-to-electrical conversion elements in imaging devices from the viewpoint of reliability and target light wavelength.

When performing XY scanning using a line sensor, a scanning device that performs optical scanning is used auxiliary.

Since it is desired that the imaging device be compact and generate little noise during operation, it is desirable that the scanning device be formed to meet these demands.

[Conventional technology]

Conventional scanning devices include those using a vibrating mirror and those using a rotating polygon mirror.

The former scans the light beam by vibrating the reflecting surface of a reflecting mirror, and does not allow it to pass through high-speed scanning.

One example of the latter is shown schematically in the plan view of FIG. 3 (11) and the side view of (bl), and another example is shown schematically in the side view of FIG.

The scanning device shown in FIG. 3 includes a prismatic rotating polygon mirror 1 having a plurality of reflective surfaces on its outer circumferential surface, a motor 2 for rotating the rotating polygon mirror 1, and a line sensor that detects an incident light beam B reflected by the rotating polygon mirror 1. It is composed of a condensing system 3 such as a lens, etc., for condensing light onto a lens.

This scanning device uses the rotation of a rotating polygon mirror 1 to generate an incident light beam B.
is scanned in the direction shown in the figure (a1), and if the rotating polygon mirror 1 is, for example, an eight-sided mirror, scanning is performed eight times in one rotation. However, if the scanning area is to be further enlarged, the reflecting surfaces of the rotating polygon mirror 1 are provided with mutually different inclination angle deviations α.

The scanning device shown in FIG. 4 is a rotating polygon illumination device shown in FIG.
The rotating polygon mirror 1a changes from a prismatic shape to an umbrella shape,
A reflecting mirror 5 is provided between the rotating polygon mirror 1a and the condensing system 3. Further, the action of the tilt angle deviation α shown in FIG. 3 is performed by vibration that changes the tilt angle of the reflection lI5.

The rotation of the rotating polygon mirror 1 or 1a enables high-speed scanning, and an imaging device using these scanning devices is capable of real-time imaging comparable to that of a television.

[Problem that the invention seeks to solve]

However, in the scanning device shown in FIG. 3, although the optical path of the incident light beam B is outside the rotating polygon mirror l, the length of the reflecting surface of the rotating polygon mirror 1 in the rotation direction becomes long, and the rotating polygon mirror 1 becomes large. Therefore, there is a problem that an imaging device using this scanning device becomes large. In addition, since the boundaries of the reflective surfaces of the rotating polygon mirror l are angular, the wind noise caused by the rotation is large.
This poses a problem when used in medical thermal cameras, etc., which are sensitive to noise.

Furthermore, the scanning device shown in FIG. 4 can make the length of the reflecting surface of the rotating polygon mirror 1a in the rotation direction shorter than that of the rotating polygon mirror 1, and is smaller in size than the rotating polygon mirror 1. However, since the optical path of the incident light beam B is outside the rotating polygon mirror 1, an imaging device using this scanning device also has the problem of becoming large, and the problem of wind noise also remains. Furthermore, when the reflecting mirror 5 is vibrated, there is a problem that its operation tends to become unstable.

1 problem 4 solution t6''''''5'' means)
1 The above problem is caused by a rotating polygon mirror that has a plurality of reflective surfaces on its inner circumferential surface that is shaped like an umbrella, and the reflective surfaces intersect with the rotation axis of the rotating polygon mirror so that the incident light is reflected by the rotating polygon mirror. The problem is solved by the scanning device of the present invention, which includes a reflecting mirror that receives a beam of light and causes the optical axis of the beam to substantially coincide with the axis of rotation.

According to the present invention, it is desirable that at least the outer circumferential surface of the rotating polygon mirror has a smooth surface in the direction of rotation.

[Effect]

In the above-mentioned scanning device, the optical path of the incident light beam reflected by the rotating polygon mirror is inside the inner circumferential surface, and the condensing system and line sensor conventionally placed outside the rotating polygon mirror are located on the rotation axis. However, since the rotating polygon mirror has a reflecting surface arranged in an umbrella shape, it becomes smaller as in the case shown in FIG. It becomes possible to significantly reduce the size.

Further, since there is no need to provide a reflective surface on the outer peripheral surface of the rotating polygon mirror, by making the surface smooth in the direction of rotation, it is possible to reduce wind noise, which has been a problem in the past.

〔Example〕

The configuration of an embodiment of the scanning device according to the present invention will be explained below with reference to a side cross-sectional view ta+ and a front view (bl) in FIG. .The same reference numerals indicate the same objects throughout the figures.

The main configuration of the scanning device shown in FIG. 1 is that the rotating polygon mirror 1a shown in FIG. The line sensor 4 is also arranged on the rotation axis A, and the incident light beam B enters the rotating polygon mirror 11 from the front side.

The rotating polygon mirror 11 has an umbrella-shaped depression that is open on the incident side of the incident light beam B, and the inner circumferential surface of the depression is inclined at about 45 degrees, and a plurality of mirrors are arranged at equal intervals along the circumferential direction. A reflective surface 12 is arranged. It is rotatably supported by a cylindrical support tube 6 disposed concentrically with the rotation axis A via, for example, a bearing, and rotated by being driven by the motor 2 via a rotation transmission means 21 such as a timing belt. do.

Further, as shown in FIG. 2, the outer peripheral surface 1 of the rotating polygon mirror 11
3 is formed smoothly without any angularity, and the boundary portion 14 between adjacent reflective surfaces 12 is also formed so as not to have any angularity.

The reflecting mirror 51 is arranged with the center of its reflecting surface 52 aligned with the rotation axis A and at an angle of about 45 degrees at a position connecting the opposing reflecting surfaces 12.

The condensing system 3 is supported inside the support tube 6 with its central axis aligned with the rotation axis A, and the line sensor 4 is located on the opposite side of the condensing system 3 from the reflecting mirror 51 .

This scanning device uses an incident light beam B incident on a rotating polygon mirror 11.
is reflected by the reflective surface 12 and advanced toward the rotation axis A, and is reflected by the reflective surface 52 so that the optical axis substantially coincides with the rotation axis A, and the condensing system 3
The light is focused at the position of the line sensor 4. At this time, by rotating the rotating polygon mirror 11, the incident light beam B is scanned in the direction a shown in FIG. 1(b), as in the case shown in FIG.

Furthermore, scanning in the direction shown in FIG. 1(a) is performed by scanning within the line sensor 4, as explained in FIG.
This is done by providing mutually different inclination angle deviations α. For this reason,
Since there is no need to apply vibrations to the reflecting mirror 51 as applied to the reflecting mirror 5 shown in FIG. 4, there is no problem of unstable operation.

Thus, in this scanning device, the optical path of the incident light beam B is contained within the rotating polygon mirror 11, and since the rotating polygon mirror 11 is small, an imaging device using this scanning device can achieve real-time performance comparable to that of a television. Although it is possible to capture images of

Furthermore, since the inner and outer circumferential surfaces of the rotating polygon mirror 11 have no angular parts with respect to the direction of rotation, wind noise caused by rotation is reduced compared to the conventional case, and the polygon mirror 11 can be used in medical thermal cameras and the like where noise is averse.

In addition, in FIG. 1(a), the support tube 6 is the rotating polygon mirror 1.
1, the diameter may be increased to support the peripheral portion of the rotating polygon mirror 11 (Also, the rotation transmitting means 21 may be a gear or a roller other than a timing belt. Also, instead of a refractive type such as a lens, a reflective type such as a Cassegrain mirror can be used for the condensing system 3.

〔Effect of the invention〕

As explained above, according to the configuration of the present invention, it is possible to arrange the condensing system and the line sensor, which were conventionally arranged outside the rotating polygon mirror, on the rotation axis of the rotating polygon mirror. It is possible to provide a scanning device in which wind noise caused by the rotation of a rotating polygon mirror is reduced, and this has the effect of making it possible to downsize and reduce noise of an imaging device that uses the scanning device.

[Brief explanation of the drawing]

In the drawings, FIG. 1 is a side sectional view (a) and a front view (b) schematically showing the configuration of an embodiment of the scanning device according to the present invention, and FIG. 2 is a partially cutaway side view of the rotating polygon mirror. FIG. 3 is a plan view (al) and a side view (b) schematically showing the configuration of an example of a conventional scanning device.
FIG. 4 is a side view schematically showing the configuration of another example. In addition, in the figure, 1, la, 11 are rotating polygon mirrors, 12 is a reflective surface of 11, 13 is an outer peripheral surface of 11, 14 is a boundary of 12,
2 is a motor, 21 is a rotation transmission means, 3 is a condensing system, 4 is a line sensor, 5.51 is a reflecting mirror, 52 is a reflecting surface of 51, 6 is a support tube,
A is the rotation axis of 11, B is the incident light flux,
a and b indicate the scanning direction, and α indicates the tilt angle deviation, respectively. Send Akibetsu 2 song number 452T

Claims (2)

[Claims] (1) A rotating polygon mirror having a plurality of reflective surfaces on its inner peripheral surface forming an umbrella shape, and the reflecting surfaces intersect with the rotation axis of the rotating polygon mirror at an angle, and receive the incident light beam reflected by the rotating polygon mirror. A scanning device comprising: a reflecting mirror that substantially matches the optical axis of the light beam with the rotation axis. (2) The scanning device according to claim 1, wherein at least an outer circumferential surface of the rotating polygon mirror forms a smooth surface in the rotation direction.