JPH03107811A - Scanning optical system - Google Patents

Abstract

PURPOSE:To decrease the number of parts and to reduce the size of the device and the cost thereof by unitizing a lens integrated with the functions of a collimator lens and a cylindrical lens and a light source in the state of adjusting their positions and mounting the unit in the optical axis direction. CONSTITUTION:The positions of the lens 2 of one-element constitution and the light source are adjusted and the exit beam from the light source 1 is collimated to collimated beams of light. Both are unitized in this state. Further, the position of the unit 3 with respect to a polygon mirror 4 is adjusted so that the beams are focused on the reflection surface of the polygon mirror 4. The number of the parts, such as lens and holder, is decreased in this way and the size and cost of the device are reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a scanning optical device used in a laser beam printer, etc., and in particular, a scanning optical device that performs adjustment by integrating a collimator lens and a cylindrical lens that receive a light beam from a light source. The present invention relates to a scanning optical device having a configuration that makes it possible to do this.

[Prior Art] Conventionally, focus adjustment of a light source that emits a laser beam and a collimator lens, as well as adjustment of a cylindrical lens, in a scanning optical device are performed in accordance with steps 1 and 1 as shown in FIG. First, light source 20
The collimator lens 27 is moved in the direction of the optical axis to adjust the q and ↑ beams emitted from the light source 2 so that they become parallel beams.
For example, the positional relationship between the collimator lens 27 and the collimator lens 27 is fixed as a unit 30, and this parallel light is further focused in the sub-scanning direction (the direction perpendicular to the main scanning plane formed by the scanning beam over time) using a polygon mirror 24-. The cylindrical lens 28 was moved in the optical axis direction so as to form a straight line.

[Problems to be Solved by the Invention] However, in the conventional example described above, a holder for supporting the lens barrel of the collimator lens 27, a holder for supporting the light source 20, and a holder for supporting the cylindrical lens 28 are separately required, which reduces the number of parts and reduces the number of light sources. The distance from 20 to the surface of the polygon mirror 24 has been prevented from being reduced by -1.

In addition, at least two collimator lenses and cylindrical lenses are required, which increases costs.

Therefore, in view of the above-mentioned problems, an object of the present invention is to provide a scanning optical device that can reduce the number of parts, make the device more compact, and reduce costs (14 components).

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a scanning optical system that scans a light beam from a light source onto an irradiated object -1- such as a Si medium through a deflector such as a polygon mirror. In the apparatus, a unit is provided in which a lens means that integrates the functions of a collimator lens and a cylindrical lens and a light source are aligned or focused in a predetermined relationship, and this unit is used as a deflector. It is attached with its position adjusted in the optical axis direction.

]: Examples of the form of the lens means include a single-lens lens (for example, a lens with one surface having a spherical surface and the other surface a cylindrical surface, or a lens with IUfii having a toric curve and the other surface having a diagonal surface), or a collimator lens. There is a lens means in which a cylindrical lens and a cylindrical lens are embedded in the same Tar':B, and in particular, a single-lens lens is formed from plastic, etc., which is easy to mold.

[Example 1 Hereinafter, the present invention will be described in detail with reference to the drawings.

Figure 1 shows the configuration at -1:13 in the scanning direction cross-section of the first embodiment, and as shown in image No. 13, a Q1 beam C is emitted from a light source 1 such as a semiconductor laser which is modulated and manipulated. After passing through a lens 2 made of plastic or the like that integrates a collimator lens and a cylindrical lens, it is collimated into parallel light m in the main scanning direction, and converged into a focal line in the sub-scanning direction. ] and the polygon mirror 4 is about q people's size. Then, this person's q/[beam is deflected by a polygon mirror 4, and an f/θ lens 5 (where f is the focal length and q is the angle of the light beam and O is the angle O), the ideal retention is 1゛・0. Recording medium 6 via Len 7:)
The image is scanned in ten directions. Since the recording medium 6 moves or rotates by a predetermined amount in the sub-scanning direction for each main scan, two-dimensional image information is formed on this medium 61.

Next, FIGS. 2(a) and 2(b) respectively show a schematic configuration in a cross-section in the first scanning direction and a schematic configuration in a cross-section in the sub-scanning direction if+F of the optical path from the optical path (1 to the polygon mirror 4). As can be seen from Figure 2 (a) and (b), one side 117j of the lens 2σ (the surface on the light source 1 side) is a spherical surface,
The other surface (F?i'i on the polygon mirror 4 side) is a cylindrical surface that does not have curvature in the main scanning horn direction but has curvature only in the sub scanning direction.

The lens 2 is designed to accommodate such a configuration.Adjustment is performed, for example, as follows.

First, as shown in FIG. 2(a), from lens 2' to lens 2
By adjusting the movement to the position of
Focus: A2 so that the beam is incident on . Next, see Figure 2 (
As shown in b), after adjusting the focus of the light source and lens 2 as described above, they are combined into a unit, and the polygon mirror 4
1, for example, unit 3' so that the focal line is connected in the sub-scanning direction
By adjusting the optical axis direction from the position of to the position of the unit 3, the beam p', which was not a focal line on the reflective surface of the polygon mirror 4, is adjusted so that it becomes a beam p and is connected to a focal line. Ru.

In the first embodiment, the positions of the one-lens lens 2 and the light source are adjusted so that the beam emitted from the light source becomes parallel light, and the two are combined into a unit, and the position of this unit 3 relative to the polygon mirror 4 is Adjust and polygon mirror 4
Since the focal line is formed on the reflective surface of the mirror, the number of parts such as lenses and holders is reduced, making it possible to make the device more compact and lower in price.

FIG. 3 shows a cross-sectional configuration in the sub-scanning direction of the second embodiment. In the second embodiment, one surface (the surface on the light source 1 side) of the lens 12, which is a combination of a collimator lens and a cylindrical lens, is a toric surface, and the other surface (the surface on the polygon mirror 4 side) is a flat surface. Other points are substantially the same as the first embodiment.

In the second embodiment, only one side of the lens 12 needs to be formed into a toric surface, which further reduces costs.
Since the other side of the lens 12 is simply a flat surface, the means for supporting the lens 12 can be simplified.

Next, a third embodiment shown in FIG. 4 will be described.

In the third embodiment, the collimator lens 7 and the cylindrical lens 8 are integrated into the same lens barrel 9, and after the focus adjustment with the light source 1 is performed, the unit 3 is adjusted in the optical axis direction. The focal lines are connected on the reflective surface of the

Even with this configuration, there is no need to support the collimator lens 7 and the cylindrical lens 8 separately, and the number of parts can be reduced and the device can be made more compact. Other points are substantially the same as the above embodiments.

In the fourth embodiment shown in FIG. 5, the order in which the collimator lens 7 and the cylindrical lens 8 are assembled into the lens barrel 9 is reversed compared to the third embodiment, and the same effect as in the third embodiment can be obtained. .

[Effects of the Invention] As explained above, according to the present invention, the functions of the collimator lens and the cylindrical lens are integrated, the positions of the collimator lens and the cylindrical lens are adjusted, and the light source and the integrated lens are made into a unit. Since this unit is mounted with its position adjusted in the optical axis direction, the number of parts such as lenses and supporting means can be reduced, and the device can therefore be made more compact and inexpensive.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention, and FIG.
), (b) are diagrams for explaining the present invention in detail, FIG. 3 is a diagram for explaining the second embodiment, FIG. 4 is a diagram for explaining the third embodiment, and FIG. is a diagram for explaining the fourth embodiment,
FIG. 6 is a diagram showing a conventional example.

Claims (1)

[Claims] 1. In a scanning optical device that scans a light beam from a light source onto an irradiated object via a deflector, the light source includes a lens means that integrates the functions of a collimator lens and a cylindrical lens. A scanning optical device, wherein a unit is provided with the position adjusted in a predetermined relationship, and the unit is attached to the deflector with the position adjusted in the optical axis direction. 2. The scanning optical device according to claim 1, wherein said lens means comprises a single lens having one surface having a spherical surface and the other surface having a cylindrical surface. 3. The scanning optical device according to claim 1, wherein said lens means comprises a single lens having one surface having a toric surface and the other surface having a flat surface. 4. The scanning optical device 5 according to claim 2 or 3, wherein the single-lens lens is made of plastic; and the lens means is constructed by incorporating a collimator lens and a cylindrical lens into the same lens barrel. 1. The scanning optical device according to 1. 6. The collimator lens and cylindrical lens are:
6. A scanning optical device according to claim 5, wherein the former is arranged on the light source side and the latter is arranged on the deflector side. 7. The collimator lens and cylindrical lens are
6. The scanning optical device according to claim 5, wherein the former is arranged on the deflector side and the latter is arranged on the light source side.