JPH03228011A - Rotating optical scanning body and optical scanning device using the same - Google Patents

Abstract

PURPOSE:To offer the optical scanner which can be manufactured at low cost without using any expensive parts such as a polygon mirror by using a columnar rotary optical scanning body consisting of a 1st and a 2nd part which differ in refractive index. CONSTITUTION:The scanner 4 is arranged so that the center axis of the column is perpendicular and crosses an optical axis of incidence; and a light incidence part 4a as the 1st part having a refractive index n1 and a light projection part 4b as the 2nd part with the refractive index n2 constitute semicylindrical part. A light beam which is made incident from the light incidence part 4a is refracted only by a border surface p-r as the plane border part between the light incidence part 4a and light projection part 4b and projected in a direction at an angle alpha from the optical axis of a light source 2. The light beam emitted by the light source 2 becomes a parallel beam by passing through the lens 3 and is made incident on the scanner 4. The light from the light source 2 is made incident on the light incidence part 4a of the scanner 4 and then refracted by the border surface p-r between the light incidence part 4a and light projection part 4b and projected in the direction at the angle alpha from the optical axis of the light source.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating optical scanning body that scans by refracting light from a light source, and an optical scanning device using the same.

[Prior Art] Conventionally, as a method of scanning light from a light source in an in-plane direction,
A method of changing the angle of the laser beam reflecting surface by rotating a polygon mirror as shown in FIG. 7 was considered. That is, the light beam from the light source 20 is focused by the lens 21 , reflected by the polycon mirror 22 , and formed into an image on the photosensitive drum 24 via the f-θ rinse 23 . As the polygon mirror 22 rotates, a light beam scans over the photosensitive drum 24.

[Problems to be Solved by the Invention] However, since polygon mirrors are difficult to manufacture and expensive, there is a problem in that it is difficult to reduce the cost of the optical scanning device.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an optical scanning device that is easy to manufacture and inexpensive.

[Means for Solving the Problems] In order to solve this object, the optical scanning device of the present invention includes a light source, a first portion and a second portion having a light-transmitting property and having different refractive indexes. and a light beam incident on the first part from the light source is refracted at a plane boundary between the first part and the second part, and then emitted from the second part. a rotating light scanning body for rotating the rotating light scanning body; a driving means for rotating the rotating light scanning body; a control means for controlling the driving means; and polarizing means.

Further, the rotating light scanning body has a cylindrical shape, the central axis of the cylinder is arranged perpendicular to the light beam, and the first part is a concentric cylinder having a diameter equal to or less than the diameter of the cylinder. Preferably, it is a semi-cylindrical portion.

[Operation] According to the present invention having the above-described configuration, a light beam incident on the first portion from a fixed light source is transmitted to the plane boundary between the first portion and the second portion having different refractive indexes. The light is refracted and emitted from the second portion. At this time, by controlling the control means or the driving means to rotate the rotary optical scanning body, the angle of the emitted light with respect to the incident optical axis can be changed. The light beam emitted from the rotating optical scanning body is linearly scanned at a constant speed by the polarizing means.

Further, the rotating light scanning body has a cylindrical shape, the central axis of the cylinder is arranged perpendicular to the incident light beam, and the first part is a semi-cylindrical part of a concentric cylinder having a diameter less than or equal to the diameter of the cylinder. If so, control of the drive means would be easier and more effective.

[Example 1] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

First, the configuration of the optical scanning device 1 of this embodiment will be explained with reference to FIGS. 1 to 3.

The optical scanning device 1 includes a light source 2 constituted by a semiconductor light source such as a laser diode or a light emitting diode;
A scanner 4 is a rotary light scanning body that has a cylindrical shape and refracts the incident light beam that has become a parallel beam by the lens 3 and emits it, and a scanner. a motor 5 as a driving means for rotating the motor 4; and a control device 6 as a control means for controlling the motor 5.
, an f-theta lens 7 having an f-theta characteristic and serving as a polarizing means for polarizing the light beam emitted from the scanner 4, and a photosensitive drum 8 which is linearly scanned at a constant speed by the light beam polarized by the f-theta lens 7. It is composed of.

Further, the scanner 4 has rigid discs 4c arranged above and below, which balance the rotation and also serve to reinforce the scanner 4. Of the two discs 4c, the lower disc 4c is fixedly connected to the shaft 5a of the motor 5, and the scanner 4 is rotated by the rotation of the motor 5.

The scanner 4 is arranged so as to be perpendicular to the central axis of the cylinder and intersect with the incident optical axis, and has a light incident part 4a which is a first part having a refractive index n1 and a light part which is a second part having a refractive index n2. The emitting portion 4b constitutes a semi-cylindrical portion. The light beam incident from the light input section 4a is refracted only at the interface pr, which is a plane boundary between the light input section 4a and the light output section 4b, and is refracted in a direction forming an angle α from the optical axis of the light source 2. It is emitted.

Here, the refractive index n of the light incident part 4a and the refractive index n2 of the light emitting part 4b have a relationship of nl<n2.

Next, the operation of the optical scanning device will be explained with reference to FIGS. 1 and 2.

The light beam emitted from the light source 2 becomes a parallel beam by passing through the lens 3, and is incident on the scanner 4. Since the optical axis from the light source 2 passes through the center O of the scanner 40, when the light ray enters the scanner 4 and exits from the scanner 4, it can proceed without being refracted. After the light beam from the light source 2 enters the light entrance section 4a of the scanner 4, it passes through the interface pr between the light entrance section 4a and the light exit section 4b.
7 which forms an angle α from the optical axis of t.
It is emitted in the j direction. According to Snell's law, the following relational expression holds between the angle θ and the angle α formed between the normal direction of the boundary surface pr and the optical axis.

sin θ/5in(θ-a) = n2/n,
−(1) Therefore, it becomes.

From equation (2), the relationship between θ and α is shown in FIG. here,
1. -1.46 (FK3: FK series optical glass, main components are S i 02-B203- and 2O-KF),
12=1. go (SF6: SF series optical glass, main component is S102-PbO-R20), t, and C. As is clear from the figure, the angle α monotonically increases as the angle θ increases. The light beam emitted from the scanner 4 is provided between the scanner 4 and the photosensitive tram 8, and has an f-theta characteristic and passes through an f-theta lens 7. Since the scanner 4 is rotated by the motor 5, the light beam passing through the f-theta lens 7 linearly scans the photosensitive drum 8 at a constant speed. Further, since the change in the angle α is constant regardless of the size of the scanner 4, the scanner 4 itself can be miniaturized.

In addition, the scanner 4 is inverted, and the light incidence part 4a with the refractive index n1 is
When the relative position of the light emitting portion 4b having the refractive index n2 with respect to the light source changes, the control device 6 controls the light source to turn off.

Next, another embodiment embodying the present invention will be described with reference to FIGS. 4 and 5.

The cylindrical scanner 10 has a refractive index n=1. 49 polycarbonate. And that circle 11-
has a cross-sectional shape or a semicircle (() in the direction of the central axis of the cylinder [
One through hole is 10a, and the center axis of the cylinder is through hole 10.
It is included in the plane part of a and is the center of the arcuate part.

Since the scanner 4 in FIG. 2 is replaced with the scanner 10 in FIG. 5, a detailed explanation of FIG. 5 will be omitted.

Since the interfaces X and Y of the scanner 10 are concentric circles about the center O, light rays incident toward the center of the scanner 10 and light rays emitted outward from the center are not refracted. Therefore, the light incident on the scanner 10 from the light source 2 is refracted only at the flat part Z of the through hole 10a, so that in the scanner of FIG. 3, n=1.00. n2=1.4
The light is scanned corresponding to the case u) shown in 9. Further, like the scanner 4, the scanner 10 has rigid discs 10b disposed above and below it, which balance the rotation and also serve to reinforce the scanner 10.

Of the two discs 10b, the lower disc 10b is fixedly connected to the shaft 5a of the motor 5, and the scanner 10 is rotated by the rotation of the motor 5.

The present invention is not limited to the embodiments detailed above, and various changes can be made without departing from the spirit thereof.

For example, the scanner may have an elliptical cylinder shape or a polygonal cylinder shape instead of a cylinder shape. However, controlling the motor that drives the scanner becomes complicated.

Further, the through hole 10a of the scanner 10 may be filled with a member having a smaller refractive index than the constituent components of the scanner 10 and having light-transmitting properties.

[Effects of the Invention] As is clear from the detailed description above, the present invention is configured without using expensive parts such as polygon mirrors, and therefore can be manufactured easily and at low cost. Providing an optical scanning device that can be used in this manner has a significant effect on the industrial sector.

[Brief explanation of drawings]

1 to 6 show embodiments embodying the present invention, FIG. 1 is a perspective view of an optical scanning device, FIG. 2 is a schematic configuration diagram of the optical scanning device of FIG. 1, Figure 3 is similar to Figure 1 and 2.
FIG. 4 is a perspective view of the scanner used in the figure, FIG. 4 is a perspective view of a scanner of another embodiment, FIG. 5 is a schematic configuration diagram of an optical scanning device using the scanner in FIG. 4, and FIG. 6 is a scanner FIG. 7 is a schematic diagram of a conventional optical scanning device. In the figure, 1 is an optical scanning device, 2 is a light source, 3 is a lens, 4 is a scanner, 4a is a light input part, 4b is a light output part, 4C is a disc, 5 is a motor, 6 is a control device, and 7 is " 0 lens, 8 is photosensitive drum, 9 is drum motor, 1O is scanner, 10a
has 11 through holes, and 10b is a disc.

Claims (1)

[Claims] 1. A light beam that has a light-transmitting property and is composed of a first part and a second part each having a different refractive index, and that is incident on the first part from a light source. is refracted at a planar boundary between the first part and the second part, and then emitted from the second part, the rotating light scanning body refracting the light at a plane boundary between the first part and the second part; A rotating optical scanning body, characterized in that the rotating optical scanning body is configured to change the intersection angle of the optical axis of the output light with respect to the optical axis of the input light. 2. The rotating light scanning body has a cylindrical shape, the central axis of the cylinder is arranged perpendicular to the light beam, and the first part is a concentric cylinder having a diameter equal to or less than the diameter of the cylinder. The rotating optical scanning body according to claim 1, wherein the rotating optical scanning body is a semi-cylindrical portion. 3. a light source; a first part and a second part having light-transmitting properties and having different refractive indexes; and a light ray incident from the light source to the first part, a rotating light scanning body that is refracted at a plane boundary between the first portion and the second portion and then emitted from the second portion; a driving means for rotating the rotating light scanning body; and a driving means for rotating the rotating light scanning body. What is claimed is: 1. An optical scanning device comprising: a control means for controlling the rotational light scanning body; and a polarization means for causing the light beam emitted from the rotating optical scanning body to scan linearly at a constant velocity. 4. The rotating light scanning body has a cylindrical shape, the central axis of the cylinder is arranged perpendicular to the light beam, and the first part is a concentric cylinder having a diameter equal to or less than the diameter of the cylinder. 4. The optical scanning device according to claim 3, wherein the optical scanning device is a semi-cylindrical portion.