JPH03220517A - optical imaging device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an optical imaging device.

Prior Art First, FIG. 3 shows an example of the prior art. A polygon mirror 1 serving as a deflector is directly connected to a motor 2, and a first mirror 3 and a second mirror 4 face the reflective surface of the polygon mirror 1.
are placed facing each other with their reflective surfaces tilted.

Reference numeral 5 denotes a cylindrical recording medium made of a photosensitive material, and this recording medium 5 is connected to a motor (not shown) to rotate. Further, a plurality of fθ lenses 6 are arranged on the optical path 8 from the polygon mirror l to the first mirror 3. Further, in the optical path 9 from the second mirror 4 to the recording medium 5, a correction lens 10 is provided for correcting an error in the image formation position on the recording medium 5 due to the surface inclination of each reflective surface of the polygon mirror 1. It is provided. Therefore, light emitted from a light source (not shown) such as a laser diode is deflected by the rotating polygon mirror 1, and this deflected light passes through the fO lens 6 and the second mirror 3°4.
The image is folded back and imaged on the outer circumferential surface of the recording medium 5.

Further, as shown in FIG. 4, instead of the fO lens 6, an fO lens 11 having a toric surface for surface tilt correction is arranged in the optical path 8 from the polygon mirror 1 to the first mirror 3, and one fO lens There is also an optical imaging device that uses only 11 to correct the focal length of the recording medium 5 and the imaging position.

Problems to be Solved by the Invention The system shown in FIG. 3 requires a correction lens 10 immediately in front of the recording medium 5 in order to correct the imaging position, which increases the number of lenses. Furthermore, in the case shown in FIG. 4, the image forming position can also be corrected using the fO lens 11, but since the optical path from this fθ lens 11 to the recording medium 5 is long, there may be slight errors in correction. There is a problem that the image is enlarged on the recording medium.

Means for Solving the Problems A first mirror facing a reflecting surface of a deflector that deflects a beam of light irradiated from a light source, and a first mirror that directs reflected light from the first mirror from the deflector to the first mirror. a second mirror that intersects with the optical path leading to the recording medium and reflects the light toward the recording medium; an fO lens is provided in the optical path leading from the deflector to the first mirror; A composite comprising: a focal length correction section that corrects a focal length with respect to the recording medium through a beam of light reaching the mirror; and a surface tilt correction section that corrects an imaging position with respect to the recording medium through a beam of light that reaches the recording medium from the second mirror. An fO lens was provided.

The light deflected from the working deflector is refracted by the first and second mirrors, and is imaged on the recording medium by the FE lens and the focal length correction section of the compound FO lens. The image formation position relative to the recording medium can be corrected with the lens, and the number of lenses can therefore be reduced.Furthermore, the correction by the surface tilt correction section of this compound fO lens can be performed just before the recording medium. , it is possible to accurately correct the imaging position.

The invention according to claim 2 does not use an fO lens other than a compound fθ lens, so that the structure can be further simplified.

Furthermore, by arranging only a compound f-theta lens that also passes the light beam from the second mirror to the recording medium in the optical path from the deflector to the first mirror, the structure is further simplified by omitting the other f-theta lenses. can do.

Embodiment A first embodiment of the present invention will be explained based on FIG. Components that are the same as those described in FIGS. 3 and 4 are designated by the same reference numerals, and description thereof will be omitted (the same applies hereinafter). The optical path 8 from the polygon mirror 1 to the first mirror 3 includes a recording medium 5.
An fO lens 6 is provided which only corrects the focal length of the lens.

Further, a compound FE lens 7 is disposed at the intersection of the optical path 8 from the polygon mirror 1 to the first mirror 3 and the optical path 9 from the second mirror 4 to the recording medium 5. This compound fO lens 7 includes a focal length correction unit 7a that corrects the focal length to the recording medium 5 by passing the light beam from the polygon mirror l to the first mirror 3, and a focal length correction unit 7a which corrects the focal length with respect to the recording medium 5 by passing the light beam from the second mirror 4 to the recording medium 5. A surface tilt correction section 7b for correcting the image formation position with respect to the recording medium 5 is formed.

In such a configuration, the light deflected from the polygon mirror l is refracted by the first and second mirrors 3 and 4, and the focal length correction unit 7 of the fθ lens 6 and the composite fθ lens 7
a, the image is formed on the recording medium 5, and further, the image formation position with respect to the recording medium 5 can be corrected by the surface tilt correction section 7b of the compound fO lens 7. Therefore, the number of lenses can be reduced. Moreover, since the correction by the tilt correction section 7b of the compound fO lens 7 can be performed just before the recording medium 5, the image forming position can be corrected accurately.

Next, a second embodiment of the present invention will be described based on FIG. 2. This embodiment includes a focal length correction unit 7a that corrects the focal length of the recording medium 5 through a light beam from the polygon mirror 1 to the first mirror 3, and a focal length correction unit 7a that corrects the focal length of the recording medium 5 by passing the light beam from the second mirror 4 to the recording medium 5. A composite rθ having a surface tilt correction unit 7b that corrects the imaging position with respect to the medium 5.
A lens 7 is provided, and with only this one compound FE lens 7,
The focal length correction and the imaging position correction are performed. Therefore, the FE lens 6 can be omitted and the structure can be further simplified.

In addition, in the first and second embodiments, the first mirror 3
A plurality of second mirrors 4 may be provided so that the reflected light from the mirror is reflected a plurality of times to form an image on the recording medium 5.

Effects of the Invention As described above, in the present invention, an fO lens is disposed on the optical path from the deflector to the first mirror, and the focal length with respect to the recording medium is corrected through the light beam from the deflector to the first mirror. A compound fO lens is provided, which has a focal length correction section and a surface inclination correction section that corrects an imaging position with respect to the recording medium through a light beam that reaches the recording medium from a second mirror that reflects light from the first mirror. By doing so, the light deflected from the deflector is refracted by the first and second mirrors, and an image is formed on the recording medium by the fθ lens and the focal length correction unit of the compound fθ lens, and the surface tilt of the compound FE lens is The correction section can correct the image formation position with respect to the recording medium, so the number of lenses can be reduced, and the correction by the surface tilt correction section of this compound fO lens can be performed just before the recording medium. Therefore, accurate correction can be performed. Furthermore, by arranging only a compound FE lens that also passes the light flux from the second mirror to the recording medium in the optical path from the deflector to the first mirror, the number of lenses can be further reduced. , the structure is further simplified by omitting the other FE lenses by arranging only a compound fθ lens that also passes the light flux from the second mirror to the recording medium in the optical path from the deflector to the first mirror. It has the following effects.

[Brief explanation of drawings]

FIG. 1 is a side view showing a first embodiment of the present invention, FIG. 2 is a side view showing a second embodiment of the present invention, and FIGS. 3 and 4 are side views showing a conventional example. . l... Deflector, 3... First mirror, 4... Second mirror, 5... Recording medium, 6... Fe lens, 7
... Composite fθ lens, 7a... Focal length correction section, 7
b...Front tilt correction section, 8, 9...Optical path

Claims (1)

[Claims] 1. A deflector that deflects a beam of light emitted from a light source;
A first mirror that faces the reflective surface of the deflector, and a second mirror that reflects the reflected light from the first mirror toward the recording medium by intersecting the optical path from the deflector to the first mirror. an fθ lens disposed on an optical path from the deflector to the first mirror, and a focal length correction unit that corrects a focal length with respect to the recording medium through a light beam from the deflector to the first mirror. and a surface tilt correction unit that corrects the image formation position with respect to the recording medium through a light beam from the second mirror to the recording medium.
An optical imaging device characterized by comprising a lens. 2. The optical imaging device according to claim 1, wherein only a compound fθ lens that also passes the light beam from the second mirror to the recording medium is disposed on the optical path from the deflector to the first mirror.