JP2002131670A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely obstruct the occurrence of trouble in images by stray light and to ensure high-quality scan processing with simple constitution. SOLUTION: A laser beam irradiation mechanism 42 has a light source section 50, a light beam scanning section 52 and an optical surface plate 54. The light beam scanning section 52 is formed by subjecting a lower flange section 82 and upper flange section 84 constituting a polygon mirror 62 to black color treatment as antireflection treatment and subjecting leaf springs 88a, 88b, 90a and 90b for fixing first and second fθ lenses 64 and 66 to black color treatment. The wall section of the optical surface plate 54 is provided with rugged-shape areas 94 continuous with each other at a pitch P below the irradiation diameter of a laser beam L to the wall section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical scanning device for recording or reading an image by irradiating a light beam emitted from a light source section to a scanned object via a light beam scanning section.

[0002]

2. Description of the Related Art For example, stimulable phosphors (stimulable phosphors)
There is known a system that once records radiation image information of a subject such as a human body, reproduces the radiation image information on a photographic photosensitive material such as a photographic film, or outputs a visible image on a CRT or the like. I have.

The stimulable phosphor is composed of radiation (X-ray, α-ray, γ
(Rays, electron beams, ultraviolet rays, etc.), a part of this radiation energy is accumulated, and after irradiation with excitation light such as visible light, a phosphor that emits stimulated emission according to the accumulated energy is referred to. This stimulable phosphor is usually used as a stimulable phosphor sheet. In the above system, for example,
While transporting the stimulable phosphor sheet on which the radiation image information of the subject has been once recorded in the sub-scanning direction, the stimulable phosphor sheet is irradiated with excitation light in the main scanning direction (a direction substantially orthogonal to the sub-scanning direction). An optical scanning device that photoelectrically reads the radiation image information is employed.

Further, in the above-described system, in order to reproduce the radiation image information read from the stimulable phosphor sheet into, for example, a photographic film, the photographic film is conveyed in the sub-scanning direction while light is applied to the photographic film. An optical scanning device that irradiates a beam in the main scanning direction is employed.

[0005] For example, as shown in FIG. 5, a light source 1 for emitting a light beam L and a light source 1
And a light beam scanning unit 2 for deflecting the light beam L emitted from the light source and irradiating the light beam L to a scanning object (not shown). The light beam scanning unit 2 includes a deflecting mirror, for example, a polygon mirror 3 which is a rotating polygon mirror, an fθ lens 4, and a reflecting mirror 5 for deflecting the light beam L by approximately 90 °. The light beam scanning unit 2 is positioned and arranged on an optical surface plate 7 provided in a casing 6.

[0006]

However, in the above-described optical scanning device, after the light beam L is diffusely reflected by the reflection mirror 5 or the like, the leaf spring 8 or the polygon holding the fθ lens 4 on the optical surface plate 7 is used. There is a possibility that the light is reflected by the flange portions 9 provided above and below the mirror 3 and is applied to the reflection mirror 5 as reflected light L1.

Further, when the light beam L is directly applied to the optical surface plate 7 by the polygon mirror 3 or the like, or when the light beam L is reflected by the fθ lens 4 or the like, the light surface L is applied to the optical surface plate 7. There are cases. At this time, the light beam L applied to the optical base 7 may be reflected on the wall surface of the optical base 7 and irradiated on the reflection mirror 5.

As a result, the reflected light L1 or the like is radiated as stray light to the scanning portion (or in the vicinity) of the object to be scanned, and if the object to be scanned is a stimulable phosphor sheet, the stray light affects the read image. As a result, the image reproduced on the photographic film is likely to have defects such as uneven stripes. On the other hand, if the object to be scanned is a photographic film,
A defect due to stray light easily occurs in a recorded image. Therefore, it has been pointed out that high-quality image information reading processing and image recording processing are not performed.

SUMMARY OF THE INVENTION The present invention is to solve this kind of problem. When an object to be scanned is irradiated with a light beam, it is possible to reliably prevent the occurrence of a defect on an image due to stray light, and to achieve a high quality image with a simple configuration. It is an object to provide an optical scanning device capable of performing a scanning process.

[0010]

In an optical scanning device according to the present invention, an anti-reflection process is performed on a light beam deflecting mirror and a member close to a lens system constituting a light beam scanning unit, and an optical surface plate is provided. Corresponding to the wall to which the light beam is applied, a continuous uneven portion is provided at a pitch equal to or less than the irradiation diameter of the light beam. As a result, it is possible to effectively prevent unnecessary reflected light and the like from existing on the optical path of the light beam as stray light, and to reliably avoid occurrence of a defect in image information reading processing and image recording processing due to the stray light. Become.

The light beam deflecting mirror is a rotary polygon mirror, and a flange portion provided at at least one end of the rotary polygon mirror is subjected to black processing as antireflection processing. For this reason, the reflectance at the flange portion of the rotary polygon mirror is greatly reduced, and the occurrence of a defect on an image due to stray light can be effectively prevented with a simple configuration.

Further, the light intensity of the stray light reaching the surface of the object to be scanned is adjusted to 0.005% or less of the light intensity of the light beam to be applied to the surface of the object to be scanned. This makes it possible to prevent the irradiation of even a small amount of stray light other than the main beam, especially when performing a highly sensitive reading operation on the stimulable phosphor sheet. Accordingly, occurrence of streak unevenness due to the stray light is prevented, and highly accurate image recording processing or image reading processing is efficiently performed.

[0013]

FIG. 1 is a schematic diagram illustrating the configuration of an image information reading apparatus 10 in which an optical scanning device according to an embodiment of the present invention is incorporated.

A cassette 14 in which a stimulable phosphor sheet S, which is a scanning object on which radiation image information of a subject is once recorded, is stored in an apparatus main body 12 constituting the image information reading apparatus 10. A loading unit 16 and a reading unit (optical scanning unit) that irradiates a laser beam (light beam) L as excitation light to the stimulable phosphor sheet S on which the radiation image information is recorded, and reads the radiation image information photoelectrically. And an erasing unit 20 for erasing radiation image information remaining on the stimulable phosphor sheet S after reading.

The cassette 14 has a housing 22 for accommodating the stimulable phosphor sheet S, and an openable / closable end of the housing 22 for taking out and inserting the stimulable phosphor sheet S. And a lid 24 to be mounted. The cassette loading unit 16 inserts the cassette 14 in a horizontal posture, and also includes a cover opening / closing means (not shown) for opening and closing the cover 24, and sucks and holds the stimulable phosphor sheet S from the cassette 14, takes out the stimulable phosphor sheet S from the cassette 14, and performs reading and reading. A sheet feeding means 28 having an adsorption plate 26 for feeding the stimulable phosphor sheet S after the erasing process to the cassette 14;

Downstream of the single-wafer means 28, a reciprocating transport system 30
The erasing unit 20 and the reading unit 18 are provided via the. The reciprocating transport system 30 includes a plurality of paired rollers 32. The erasing unit 20 is disposed in a vertical transport path defined by the pair of rollers 32, and the horizontal transport defined by the pair of rollers 32. The reading unit 18 is arranged above the road. The erasing unit 20 includes a plurality of erasing light sources 34 extending in the horizontal direction.

The reading section 18 includes a stimulable phosphor sheet S
Scanning transport mechanism 40 that reciprocates the stimulable phosphor sheet S in the horizontal direction (arrow X direction) and the stimulable phosphor sheet S that is sub-scanning transported in the arrow X1 direction. A laser beam irradiation mechanism 42 for irradiating the stimulable phosphor sheet S in the main scanning direction by irradiating the stimulable phosphor sheet S and stimulating light emitted from the stimulable phosphor sheet S.
And a reading mechanism 44 that photoelectrically reads the radiation image information carried by the reading device.

The sub-scanning transport mechanism 40 includes a first roller pair 4 and a second roller pair 4 which are horizontally spaced from each other by a predetermined distance.
6, 48. First and second roller pairs 46, 48
Are synchronously driven to rotate via a motor (not shown).

FIG. 2 and FIG.
As shown in FIG. 5, a light source unit 50 that emits laser light L, and deflects the laser light L emitted from the light source unit 50,
A light beam scanning unit 52 for irradiating the stimulable phosphor sheet S conveyed in the sub-scanning direction with the laser beam L in a substantially vertical direction (arrow Y direction) to perform main scanning; It is attached to.

The light source unit 50 includes an LD assembly 56 fixed to the optical platen 54. This LD assembly 56
Includes a semiconductor laser 58 and a collimator lens 60 arranged on the laser beam emission side of the semiconductor laser 58. Between the light source unit 50 and the light beam scanning unit 52, optical components 61a and 61b such as lenses and prisms are mounted along the optical path of the laser light L.

The light beam scanning unit 52 includes a light beam deflecting mirror, for example, a polygon mirror (rotating polygon mirror) 62,
Lenses, first and second fθ lenses 64 and 66, a prism mirror 68, a cylindrical lens 70, a cylindrical mirror 72, and a cover glass 74.

As shown in FIG. 3, the polygon mirror 62 has a rotation base 80 which is driven to rotate by a motor 78.
The rotation base 80 has a lower flange portion 82
In addition, six reflecting surfaces 86 are provided at equal angular intervals so as to be sandwiched by the upper flange portion 84 (see FIGS. 3 and 4). At least one end of the polygon mirror 62, in this embodiment, a lower flange portion 82 and an upper flange portion 84 provided at both upper and lower ends are subjected to, for example, black processing as antireflection processing.

The first and second fθ lenses 64 and 66 are
The plate springs 88a, 88b, 90a, and 90b are positioned and held on the optical platen 54 via the plate springs 88a, 88b, 90a, and 90b, and the plate springs 88a, 88b, 90a, and 90b are subjected to black processing as antireflection processing. Similarly, the optical component 6
The plate springs 92a and 92b for positioning and holding the substrates 1a and 61b on the optical platen 54 are subjected to black processing as antireflection processing.

In the optical surface plate 54, the inner surface thereof is subjected to black processing as necessary, and at least the laser beam L is directly or optically provided by the first and second fθ lenses 64 and 66 and the prism mirror 68. An uneven portion 94 is provided on the wall portion to be reflected and irradiated. The uneven portions 94 are continuously provided at a pitch P equal to or less than the irradiation diameter of the laser beam L on the wall. On the inner wall of the optical base 54, a tapered surface inclined in the sub-scanning direction with respect to the optical path of the laser light L is provided as necessary.

As shown in FIG. 3, the optical surface plate 54 has a light beam exit port 96 for emitting the laser beam L reflected by the cylindrical mirror 72 in a substantially vertically downward direction (the direction of arrow Y). The cover glass 74 is attached to the light beam emission port 96. An optical unit cover 98 is fixed to the upper part of the optical surface plate 54. The optical section cover 98 is formed with a groove 100 that engages with the optical surface plate 54, and a seal member (not shown) is interposed in the groove portion 100 to keep the inside of the optical surface plate 54 lighttight. ing.

The reading section 18 provides the above-described anti-reflection processing (for example, black processing) and the provision of the uneven portion 94 so that the laser beam L to be irradiated on the stimulable phosphor sheet S can be obtained.
The light intensity of the stray light reaching the stimulable phosphor sheet S is adjusted to 0.005% or less with respect to the light intensity of.

As shown in FIG. 1, the reading mechanism 44
A light collecting guide 102 is provided for collecting stimulated emission light emitted from the stimulable phosphor sheet S by irradiation with the laser light L. A photomultiplier 104 is connected to an end of the light collecting guide 102. A reflection mirror 106 that reflects stimulated emission light to the light-collecting guide 102 is disposed near the tip of the light-collecting guide 102.

The image information reading apparatus 1 configured as described above
The operation of 0 will be described below.

First, the cassette 14 is mounted on the cassette loading section 16 provided on the upper portion of the apparatus main body 12 so as to be oriented in the horizontal direction. The cassette 14 accommodates a stimulable phosphor sheet S in which radiation image information of a subject (not shown) is recorded in advance, and under the action of a cover opening / closing means (not shown) provided in the cassette loading section 16. , Lid 24
Is released.

Next, the sheet feeding means 28 is driven to move the suction plate 26 into the cassette 14, and the suction surface of the stimulable phosphor sheet S in the cassette 14 is suction-held by the suction plate 26. Further, the suction disk 26 is attached to the cassette 14.
Then, the stimulable phosphor sheet S in the cassette 14 moves from the inside to the reciprocating transport system 30 side, is sucked by the suction disk 26, and is taken out from the cassette 14. At about the same time that the leading end of the stimulable phosphor sheet S taken out of the cassette 14 is sandwiched by the pair of rollers 32, the suction and holding of the stimulable phosphor sheet S by the suction disk 26 is released.

As a result, the stimulable phosphor sheet S is conveyed vertically downward by the rotation of the plurality of roller pairs 32. This stimulable phosphor sheet S is
Through the sub-scanning transport mechanism 40 constituting the reading unit 18. In the sub-scanning transport mechanism 40, the stimulable phosphor sheet S is sandwiched between the first and second roller pairs 46 and 48, and is rotated in the direction of arrow X1 by the rotation of the first and second roller pairs 46 and 48. Conveyed.

At this time, as shown in FIG. 2, a laser beam L is emitted from a semiconductor laser 58 constituting the light source unit 50,
The laser light L is applied to the polygon mirror 62 via the optical components 61a and 61b.

As shown in FIGS. 3 and 4, in the polygon mirror 62, the rotation base 80 is rotated under the action of the motor 78, and the laser light L is transmitted by the reflection surface 86 constituting the polygon mirror 62. It is reflected and deflected. The deflected laser light L passes through the first and second fθ lenses 64 and 66 and irradiates the prism mirror 68 as shown in FIGS.
After being refracted in 8, the light is incident on a cylindrical lens 70 arranged below the second fθ lens 66. The laser light L incident on the cylindrical lens 70
Is reflected vertically downward by the cylindrical mirror 72, passes through the cover glass 74, and passes through the light beam exit port 96.
Is derived in the direction of arrow Y.

As shown in FIG. 1, the laser light L
The main scanning is performed by irradiating the stimulable phosphor sheet S, which is being conveyed in one direction in the sub-scanning direction, onto the imaging surface in a substantially vertical direction. The irradiation of the laser light L generates stimulated emission light from the imaging surface of the stimulable phosphor sheet S, and the stimulated emission light is condensed via the condensing guide 102 and read photoelectrically by the photomultiplier 104. Can be

In this case, in this embodiment, the first and second fθ lenses 64 and 66 constituting the light beam scanning unit 52
Springs 88a, 88b, 90a, 90b for positioning and holding the optical components 61a, 61b, etc. on the optical platen 54.
For example, black processing is performed on the parts 92a and 92b as antireflection processing. Therefore, the leaf spring 88
The reflectance of a, 88b, 90a, 90b, 92a, and 92b can be significantly reduced, for example, from 30% to 5%.

Further, in the polygon mirror 62, for example, black processing is applied to the lower flange portion 82 and the upper flange portion 84 provided so as to sandwich the reflection surface 86 as antireflection processing. The reflectance of the portion 82 and the upper flange portion 84 can be greatly reduced, for example, from 40% to 5%.

Further, of the inner wall surface of the optical surface plate 54, a wall portion to which the laser beam L may be irradiated directly or after reflection is provided with a pitch smaller than the irradiation diameter of the laser beam L to this wall portion. A concavo-convex portion 94 continuous with P is formed.

This effectively prevents the laser light L derived from the semiconductor laser 58 from being unnecessarily reflected (including diffuse reflection) in the optical surface plate 54, and the stimulable phosphor sheet during scanning and reading is effectively prevented. The light intensity of the stray light irradiated to S can be significantly reduced. Therefore, the radiation image information read from the stimulable phosphor sheet S is not affected by the stray light, and when the image is reproduced on a photographic film (not shown) based on the read radiation image information, a streak is generated. It is possible to prevent the occurrence of unevenness and the like, and to obtain an effect that the reading and reproducing processing of high quality image information is efficiently performed.

In particular, in the present embodiment, the light intensity of the stray light reaching the stimulable phosphor sheet S is 0.005 with respect to the light intensity of the laser beam L to be irradiated on the stimulable phosphor sheet S.
% Has been adjusted. Therefore, even when reading is performed using the high-sensitivity stimulable phosphor sheet S, a problem due to stray light does not occur on the read image, and high-accuracy and high-quality image information reading processing can be performed. Moreover,
The configuration of the entire reading unit 18 is simplified without being complicated, and becomes economical.

In the light beam scanning section 52, a leaf spring 8 for fixing the first and second fθ lenses 64 and 66 is provided.
Although the case in which the black processing is performed on 8a, 88b, 90a, and 90b has been described, the present invention is not limited to this case. Blackening treatment can be performed as a prevention treatment. Further, the optical surface plate 54 is provided with a tapered surface whose inner wall is inclined in the sub-scanning direction with respect to the optical path of the laser beam L, thereby preventing stray light from being irradiated on the scanning line of the stimulable phosphor sheet S. Therefore, the reading process of the radiation image information is performed with high accuracy.

By the way, as described above, the stimulable phosphor sheet S for which the reading processing of the radiation image information has been completed is driven by rotating the first and second roller pairs 46 and 48 in the opposite directions as shown in FIG. As a result, the sheet is conveyed in the direction of arrow X2 and delivered to the reciprocating conveyance system 30. The stimulable phosphor sheet S is conveyed vertically upward (in the direction of arrow A), and the erasing unit 20 erases the remaining radiographic image information under the action of the erasing light source 34.
Through the cassette 14. After the cassette 14 is removed from the cassette loading section 16, the cassette 14 is used for capturing a radiation image of a subject (not shown).

Although the present embodiment has been described using the stimulable phosphor sheet S as the object to be scanned, the present invention is not limited to this, and the present invention is also applicable to the case where an image is recorded on a photographic film or the like. The same effect as in the embodiment can be obtained.

[0043]

In the optical scanning device according to the present invention, the anti-reflection processing is performed on the light beam deflecting mirror and the members adjacent to the lens system constituting the light beam scanning unit, and the light beam on the optical surface plate is reduced. The irradiated wall is provided with a continuous uneven portion at a pitch equal to or less than the irradiation diameter of the light beam to the wall, and the light intensity of stray light can be significantly reduced. Thereby, it is possible to effectively prevent the occurrence of a defect due to stray light in an image read from the scanned object or a recorded image on the scanned object, and the image can be easily formed on the scanned object with a simple configuration. The reading process and the image recording process are performed with high accuracy and efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image information reading apparatus in which an optical scanning device according to an embodiment of the present invention is incorporated.

FIG. 2 is a plan view showing a state in which a light source unit and a light beam scanning unit constituting the optical scanning device are mounted on an optical surface plate.

FIG. 3 is an end view taken along line III-III of FIG. 2;

FIG. 4 is a schematic perspective view of a polygon mirror constituting the light beam scanning unit.

FIG. 5 is an explanatory plan view of an optical scanning device according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Image information reading device 12 ... Device main body 16 ... Cassette loading part 18 ... Reading part 20 ... Erasing part 30 ... Reciprocating conveyance system 32, 46, 48 ... Roller pair 40 ... Sub-scanning conveyance mechanism 42 ... Laser beam irradiation mechanism 44 ... Reading mechanism 50 Light source 52 Light beam scanning unit 54 Optical surface plate 56 LD assembly 58 Semiconductor lasers 61a and 61b
Optical components 62: polygon mirror 64, 66: fθ
Lens 68 Prism mirror 70 Cylindrical lens 72 Cylindrical mirror 74 Cover glass 82 Lower flange 84 Upper flange 86 Reflecting surface 88a, 88b, 90a, 90b, 92a, 92b Leaf spring 94 Uneven shape Part 98 ... Optical cover S ... Storable phosphor sheet

Claims (3)

[Claims] A light source unit that emits a light beam; a light beam scanning unit that deflects the light beam emitted from the light source unit and irradiates the scanned object with at least the light beam scanning unit; An optical surface plate, wherein the light beam scanning unit performs an anti-reflection process on a member close to a light beam deflecting mirror and a lens system, and the optical surface plate has at least the light beam directly or An optical scanning device comprising: a wall portion to be reflected and irradiated by an optical component; and a continuous uneven portion provided at a pitch equal to or smaller than an irradiation diameter of the light beam to the wall portion. 2. The optical scanning device according to claim 1, wherein the light beam deflecting mirror is a rotary polygon mirror, and a flange portion provided at least at one end of the rotary polygon mirror is subjected to black processing as the antireflection processing. An optical scanning device characterized by performing: 3. The optical scanning device according to claim 1, wherein the light intensity of the stray light arriving at the surface of the scanned object is 0.
An optical scanning device characterized by being adjusted to 005% or less.