JP2003262806A - Exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an exposure device capable of preventing aberration from occurring. <P>SOLUTION: When a laser beam L emitted from a semiconductor laser LD is divided into several in a subscanning direction by an array refracting element 36 and condensed on thermal sensitive material T, it is temporarily condensed at a 1st condensing position between a fiber array part 30 and the material T by a 1st optical system constituted of a 1st collimator lens 32A and a 1st condensing lens 38A. Then, the specified areas at both ends in the subscanning direction of the laser beam L are shielded by an array aperture plate 39 at the condensing position. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus,
In particular, it relates to an exposure device that forms an image on a recording medium by scanning exposure.

[0002]

2. Description of the Related Art Conventionally, a drum having a photosensitive material (recording medium) mounted on its outer peripheral surface is rotated in the main scanning direction, and a laser beam modulated according to image data of an image to be recorded on the photosensitive material. An exposure recording apparatus is used in which a two-dimensional image is recorded on the photosensitive material by scanning in the sub-scanning direction orthogonal to the main scanning direction.

In this type of exposure recording apparatus, in order to record an image with a low resolution, the spot diameter of the laser beam on the surface of the photosensitive material is increased and the recording pitch in the sub-scanning direction is increased, or A method has been adopted in which the size of the spot diameter and the recording pitch are not changed and pixels of the same image data are repeatedly recorded by the amount corresponding to the lowered resolution. On the other hand, when recording an image with a high resolution, the opposite method has been adopted.

However, in order to enlarge or reduce the spot diameter of the laser beam in this way, it is necessary to drive the lens of the optical system by using the drive mechanism, so that the apparatus becomes large and Cost will rise,
There was a problem. Further, when the resolution is lowered by repeatedly recording the pixels of the same image data by the amount corresponding to the lowered resolution, the recording pitch in the sub-scanning direction is constant, so that the recording speed cannot be improved. was there.

Therefore, in order to solve these problems, Japanese Patent Laid-Open No. 2000-284206 by the applicant of the present invention.
In the technique described in the publication, the light emitted from the light source is divided into a plurality of light beams, and the light condensing point on the recording medium by the light condensing optical system is
A plurality of condensing point generation means for generating a plurality in the sub-scanning direction of the recording medium and a sub-scanning control means for controlling the recording interval in the sub-scanning direction according to the resolution are provided, and the light is emitted from the light source. When recording an image by condensing light on a recording medium via a condensing optical system, depending on the resolution of the recorded image,
Adjusting the size of the beam spot by controlling the number of condensing points generated by the plurality of condensing point generating means in the sub-scanning direction and adjusting the recording interval of the beam spot in the sub-scanning direction. This makes it possible to efficiently record an image according to the resolution.

In this technique, a polarization optical element formed of a uniaxial crystal or a deflection angle prism is used as the plural condensing point generating means.

However, the above-mentioned Japanese Patent Laid-Open No. 2000-284.
In the technique described in Japanese Patent No. 206, when a polarizing optical element composed of a uniaxial crystal is used as a plurality of condensing point generating means, the uniaxial crystal is expensive, resulting in high cost. was there.

Further, in the case where the deflection angle prism is applied as the plural condensing point generating means in the technique described in the publication,
There has been a problem that the quality of recorded images may deteriorate.

That is, when a deflection prism is used as a plurality of converging point generating means in the technique described in the above publication, light is emitted from a focal position of a laser beam divided by the deflection prism and condensed by a condenser lens. The defocusing direction of the laser beam at the position shifted in the axial direction (depth direction) is asymmetric with respect to the optical axis direction.

This is because the light divided by the deflection prism is condensed by the condenser lens at different positions in the dividing direction of the focal position, so that when the incident side of the light is seen from the focal position, the divided light is divided. Are separated from each other, and when the light emission side is viewed from the focus position, the divided light beams come close to each other and then cross apart from each other. This phenomenon causes the recording medium to move in the depth direction. The allowable range of the arrangement position is reduced, and even if the displacement of the arrangement position in the depth direction is slight, the image quality of the recorded image on the recording medium may deteriorate.

Therefore, in order to solve these problems, Japanese Patent Application No. 2001-310537 filed by the applicant of the present invention.
The technique described in No. 1 is an exposure device that forms an image on a recording medium by scanning exposure, and a light source that emits a light beam emitted in a broad area at least in the sub-scanning direction, and a light emitted from the light source. A condensing optical system for condensing a beam on the recording medium, and an exposure apparatus having the refraction member having a unit surface shape for dividing one light beam into two are arranged in pairs in an array. The array refracting element is arranged so that the dividing direction of the light beam is substantially parallel to the broad area direction of the light beam emitted from the light source.

As a result, the light beam divided into two by the array pair of the array refracting element is composed of light corresponding to the number of array pairs. Therefore, since one focused spot is formed by the focused beams of the number of array pairs, when the divided light beams are superposed by shifting the focused spots by two at the focal positions, the focal positions are overlapped. From the incident side of the light beam to the emission side of the light beam from the focus position, the defocusing of each light beam is symmetric with respect to the optical axis direction. Can be improved.

The array refracting element can be made of any material as long as it can divide the light beam into two. Therefore, when the light beam is split according to the polarization direction. It is not always necessary to use the necessary uniaxial crystal, and the cost can be reduced.

By the way, for the purpose of improving the recording speed,
Each laser beam emitted from a plurality of light sources is guided by an optical fiber to a single exposure head, and the end portions of the laser beam emission ports of each optical fiber in the exposure head are arranged side by side in the sub-scanning direction. There is an exposure recording apparatus that simultaneously performs exposure with a plurality of laser beams emitted from a plurality of light sources.

When the technique described in the above-mentioned Japanese Patent Laid-Open No. 2000-284206 is applied to this type of exposure recording apparatus, one laser beam can be divided into a plurality of exposures, and therefore the recording speed can be increased. Can be further improved.

However, in the exposure recording apparatus using such an optical fiber, the polarization direction of the laser beam emitted from the optical fiber is sometimes changed by the external force displacement (vibration displacement, pressure displacement, twist displacement, temperature displacement, etc.) applied to the optical fiber. It may change from moment to moment. In this case, the light amounts of the laser beams divided into a plurality compete with each other, and the focused spot has an unstable shape, which deteriorates the image quality of the recorded image. There was a problem.

In order to solve this problem, therefore, in the technique described in Japanese Patent Application No. 2001-201407 filed by the applicant of the present invention, a light source for emitting light and a light emitted from the light source are recorded on a recording medium. In an exposure apparatus including a condensing optical system that condenses light into two and a polarization separation element that separates the light into two lights whose polarization directions are orthogonal to each other, the exposure apparatus includes A polarization direction control element, which is configured by arranging a ½ wavelength plate so that the crystal optical axis is inclined at an angle of a predetermined range including 45 degrees with respect to the polarization direction of the light beam separated by the polarization separation element, is arranged. Was there.

Although the crystal optical axis is also called the "optical axis", it will be referred to as "crystal optical axis" in the present specification. Further, the above-mentioned "angle in a predetermined range including 45 degrees" is ideally 45 degrees, but an angle within a range allowable in manufacturing the polarization direction control element, the polarization direction control element is applied. It means an angle within various allowable ranges such as an angle within the allowable range of the apparatus.

Here, the principle of the present technology will be briefly described with reference to FIG. Note that, here, a case will be described where the polarization direction control element of the present technology is configured by combining a half-wave plate and a transparent parallel plate that does not significantly affect the polarization direction of transmitted light. As shown in the figure, the polarization direction of the light separated by the polarization separation element is (x,
y), the polarization direction control element is arranged so that the direction of the crystal optical axis of the half-wave plate in the polarization direction control element is inclined by 45 degrees with respect to (x, y). To do. The coordinate system of the crystal optical axis in the half-wave plate at this time is (X, Y). In addition, here, on the assumption that there is no difference in light transmittance between the transparent parallel plate and the half-wave plate in the polarization direction control element, or the difference is negligibly small, the light amount of light incident on the half-wave plate is The polarization direction control element is arranged at a position where the amount of light is distributed so that the ratio to the amount of light that does not enter becomes 1: 1.

When the electric field vector α of the light incident on the polarization direction control element is α = (a, b) and the light incident on the ½ wavelength plate is considered, the (x, y) coordinate system is 45 degrees. Let A be the matrix for rotation, B be the matrix that delays the 1/2 wavelength phase of the light at the Y coordinate, and C be the matrix that rotates -45 degrees to return to the original (x, y) coordinate system. It is expressed as.

[0021]

[Equation 1]

Therefore, the electric field vector β of the light after passing through the half-wave plate is expressed as follows.

[0023]

[Equation 2]

Since α and β are set so as to be distributed at a ratio of 1: 1 as the light quantity distribution, the respective light quantity I
α and Iβ are expressed as follows.

[0025]

[Equation 3]

Therefore, the light quantity I when the respective lights are added is as follows.

[0027]

[Equation 4]

This result shows that when the light that has passed through the half-wave plate and the light that did not pass are added together, the light separated in each of the x and y polarization directions by the polarization splitting element is equal in light amount. It shows that it is separated by.

It should be noted that the transparent parallel plate provided in the polarization direction control element is not always necessary here, and other members (for example, those that do not greatly affect the polarization direction of the incident light) are used.
An ND (Neutral Density) filter may be applied instead of the transparent parallel plate, and it is also possible to provide a blank through state without providing these members.

Based on the above principle, Japanese Patent Application No. 2001-20
The polarization direction control element in the technique described in 1407,
A polarization direction control element provided on the upstream side in the optical axis direction of the light of a polarization splitting element for splitting light into two lights having polarization directions orthogonal to each other, and provided on the upstream side in the optical axis direction of the polarization splitting element. At this time, a part of the light is transmitted and at the same time, the crystal optical axis is inclined at an angle within a predetermined range including 45 degrees with respect to the polarization direction of the light separated by the polarization separation element. Since a wavelength plate is arranged and configured, when used in combination with a polarization separation element, it becomes possible to separate light with the same amount of light by the polarization separation element, and recording in an exposure recording apparatus using the polarization separation element. The image quality of the image can be improved.

[0031]

However, the technique of the above-mentioned Japanese Patent Application No. 2001-310537 and the above-mentioned Japanese Patent Application No.
In the technique of No. 1-201407, a light beam split by an array refraction element or a polarization separation element is divided into two beams on a recording medium.
Since the center positions were shifted one by one and a part of them were overlapped, the optical power of the overlapped area increased, and the temperature of the recording medium surface corresponding to the area rapidly increased,
When a thermal type photosensitive material that records a plate by heat of light as a recording medium (hereinafter referred to as "thermal sensitive material") is applied, so-called ablation occurs in which the substance on the film surface of the thermal sensitive material scatters. There is a possibility that
There was a problem.

When ablation occurs, the scattered material adheres to various lenses and various driving systems that constitute the optical system, which not only deteriorates the quality of recorded images, but also increases the durability of the exposure apparatus and the exposure. This will adversely affect the operation of the device itself.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an exposure apparatus capable of preventing the occurrence of ablation.

[0034]

In order to achieve the above object, an exposure apparatus according to claim 1 is an exposure apparatus which forms an image on a recording medium by scanning exposure, and is broad in at least a sub-scanning direction. A light source that emits a light beam emitted in an area, a first optical system that focuses the light beam emitted from the light source between the light source and the recording medium, and a first optical system that focuses the light beam. A second optical system that focuses the light beam on the recording medium; and a second optical system that is disposed between the focus position of the light beam by the first optical system and the recording medium and that subscans the light beam. A light splitting unit that splits the light beam into a plurality of light beams in the direction; and a light blocking unit that is disposed at a position where the light beam is focused by the first optical system and that shields a predetermined region at an end portion of the light beam in the sub-scanning direction. Is equipped with.

According to the exposure apparatus of the first aspect, the light beam emitted from the light source for emitting the light beam emitted in the broad area is at least in the sub-scanning direction.
The optical system once collects light between the light source and the recording medium,
The condensed light beam is condensed on the recording medium by the second optical system. The light source includes various semiconductor lasers.

In converging the light beam on the recording medium as described above, according to the present invention, the light splitting means arranged between the condensing position of the light beam by the first optical system and the recording medium is used.
The light beam is divided into a plurality of parts in the sub-scanning direction, and a predetermined area at the end portion in the sub-scanning direction of the light beam is shielded by the light shielding means arranged at the light beam converging position of the first optical system.

That is, in the present invention, when the light beam emitted from the light source is divided into a plurality of light beams in the sub-scanning direction by the light dividing means and condensed on the recording medium, the light beam is emitted by the first optical system. Once focused between the light source and the recording medium,
At this converging position, a predetermined area at the end of the light beam in the sub-scanning direction is shielded by the light shielding means, whereby the light beam split by the light splitting means is shifted in the center position on the recording medium and a part thereof is overlapped. Since the area of the overlapping region in the case of matching is small, the optical power of this region can be reduced, and as a result, the occurrence of ablation can be prevented.

As described above, according to the exposure apparatus of the first aspect, the light beam emitted from the light source that emits the light beam emitted in the broad area is used as the light source by the first optical system at least in the sub-scanning direction. The light beam is focused once with the recording medium, the focused light beam is focused on the recording medium, and the light beam is placed between the focusing position of the light beam by the first optical system and the recording medium. The light beam is divided into a plurality of parts in the sub-scanning direction by the dividing means, and the predetermined region at the end portion in the sub-scanning direction of the light beam is shielded by the light shielding means arranged at the light beam focusing position by the first optical system. Therefore, when the light beam split by the light splitting means is shifted in the center position on the recording medium and a part of the light beam is overlapped, the area of the overlapping area becomes small, and therefore the optical power of this area should be made small. But Come, it is possible to prevent the occurrence of ablation as a result.

On the other hand, in order to achieve the above object, an exposure apparatus according to a second aspect is an exposure apparatus which forms an image on a recording medium by scanning exposure, and emits light in a broad area at least in the sub-scanning direction. A light source that emits a light beam, an optical system that condenses the light beam emitted from the light source on the recording medium, and an emission port for the light beam emitted from the light source and the recording medium. A light splitting means for splitting the light beam into a plurality of light beams in the sub-scanning direction, and a predetermined area at the end of the light beam in the sub-scanning direction, the light splitting means being arranged between the emission port and the light splitting means. And a light blocking means for blocking the light.

According to the exposure apparatus of the first aspect, at least in the sub-scanning direction, the light beam emitted from the light source for emitting the light beam emitted in the broad area is condensed on the recording medium by the optical system. . The light source includes various semiconductor lasers.

In converging the light beam on the recording medium as described above, according to the present invention, the light splitting means arranged between the exit of the light beam emitted from the light source and the recording medium,
The light beam is divided into a plurality in the sub-scanning direction, and by the light shielding means arranged between the emission port and the light dividing means,
A predetermined area at the end of the light beam in the sub-scanning direction is shielded.

That is, according to the present invention, when the light beam emitted from the light source is divided into a plurality of light beams in the sub-scanning direction by the light dividing means and condensed on the recording medium, the light beam emission port and the light beam division are performed. A predetermined region at the end of the light beam in the sub-scanning direction is shielded by a light shielding unit between the means and
As a result, the area of the overlapping region becomes small when the light beams split by the light splitting means are shifted in the center position on the recording medium and a part of them are overlapped, so that the optical power in this region can be reduced. As a result, it is possible to prevent the occurrence of ablation.

As described above, according to the exposure apparatus of the second aspect, the light beam emitted from the light source that emits the light beam emitted in the broad area is focused on the recording medium at least in the sub-scanning direction. At the same time, the light beam is divided into a plurality of parts in the sub-scanning direction by the light splitting means arranged between the light beam outlet and the recording medium, and is arranged between the light outlet and the light splitting means. Since the predetermined area at the end of the light beam in the sub-scanning direction is shielded by the light shielding means, the superposition in the case where the light beams divided by the light dividing means are shifted in their center positions on the recording medium and partially overlapped with each other. Since the area of the region is reduced, the optical power of this region can be reduced, and as a result, the occurrence of ablation can be prevented.

An exposure apparatus according to a third aspect is the exposure apparatus according to the first aspect or the second aspect, wherein the predetermined region is divided by the light splitting means from the center of the light beam. An area outside a straight line in the main scanning direction which is in contact with each of two positions separated on both end sides in the sub scanning direction by a distance corresponding to a distance in a predetermined range including half the center-to-center distance of the focused spot on the recording medium. It is what In addition, the above "distance within a predetermined range including half the distance between centers"
Is ideally half the center-to-center distance, but means a distance within various allowable ranges such as a distance within the allowable range of the exposure apparatus.

That is, in the exposure apparatus according to the third aspect, as shown in FIG. 7, the predetermined region in the invention according to the first or second aspect of the invention is divided into the light beams divided by the light dividing means of each invention. Two positions separated from the center of the light beam toward both ends in the sub-scanning direction by a distance corresponding to a predetermined range of distance including half (ΔS / 2) of the center-to-center distance ΔS of the focused spot SP on the recording medium. The area outside the straight line in the main-scanning direction in contact with each of the areas is substantially the minimum (ideally disappears) because the area of the overlapping area on the recording medium of the light beam split by the light splitting means is reduced. The optical power in this region can be reduced, and as a result, the occurrence of ablation can be almost certainly prevented.

As described above, according to the exposure apparatus of the third aspect, the predetermined spot in the present invention is formed from the center of the light beam by the light splitting means, and the condensed spot of the light beam on the recording medium is formed. A distance corresponding to a distance in a predetermined range including a half of the center-to-center distance is separated from both ends in the sub-scanning direction by 2
Since the area is located outside the straight line in the main scanning direction that is in contact with each of the three positions, it is possible to almost certainly prevent the occurrence of ablation.

In the light splitting means according to the present invention, as in the invention described in claim 4, refracting members having a unit surface shape for splitting one light beam into two are arranged in pairs in an array. And an array refraction element arranged such that the division direction of the light beam is substantially parallel to the broad area direction of the light beam emitted from the light source, or the light beam is polarized in the direction of polarization. Are orthogonal to each other 2
A polarization separation element that separates the light into two lights, and a crystal optical axis that is disposed between the light source and the polarization separation element and has a crystal optical axis of 45 degrees with respect to the polarization direction of the light beam that is separated by the polarization separation element. A polarization direction control element configured by arranging a ½ wavelength plate so as to be inclined at an angle in the range can be configured. The polarization separation element includes various prisms such as a Rochon Prism and a Wollaston Prism.

That is, the invention described in claim 4 is a technique for shielding a predetermined region at the end portion of the light beam in the sub-scanning direction, which is the main object of the present invention, is the above-mentioned Japanese Patent Application 2001.
It is applied to each invention of Japanese Patent Application No. 310537/2001 and Japanese Patent Application No. 2001-201407, and the same effect as that of the invention described in any one of claims 1 to 3 is obtained for these inventions. Can be made.

Further, in the exposure apparatus according to a fifth aspect, in the invention according to any one of the first to fourth aspects, resolution information indicating a resolution of an image formed on the recording medium by scanning exposure is provided. Input means for inputting, and when the resolution indicated by the resolution information is a predetermined first resolution, the light splitting means is retracted from the optical axis of the light beam, and the resolution indicated by the resolution information is And a moving means for moving the light splitting means so that the light splitting means is positioned on the optical axis when the second resolution is lower than the first resolution.

According to the fifth aspect of the exposure apparatus, the resolution information indicating the resolution of the image formed on the recording medium by the scanning exposure is input by the input means, and the resolution indicated by the resolution information is predetermined. In the case of the first resolution, the light splitting means of the present invention is retracted from the optical axis of the light beam emitted from the light source, and the light when the resolution indicated by the resolution information is the second resolution lower than the first resolution. The light splitting means is moved by the moving means so that the splitting means is positioned on the optical axis.

As described above, according to the exposure apparatus of the fifth aspect, the resolution information indicating the resolution of the image formed on the recording medium by the scanning exposure is input, and the resolution indicated by the resolution information is predetermined. When the resolution is the first resolution, the light splitting means is retracted from the optical axis of the light beam emitted from the light source, and the light splitting is performed when the resolution indicated by the resolution information is the second resolution lower than the first resolution. Since the light dividing means is moved so that the means is located on the optical axis, the resolution when recording an image on the recording medium can be easily changed by only inputting the resolution information.

A plurality of the light sources in the invention according to any one of claims 1 to 5 are arranged along the dividing direction of the light beam by the light dividing means, and the light emitted from each light source is arranged. If the beam is divided by the light dividing means and guided to the recording medium, not only the image quality of the recorded image can be improved but also the image can be recorded at high speed.

[0053]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In the following,
A case where the exposure apparatus of the present invention is applied to a laser recording apparatus will be described.

[First Embodiment] First, referring to FIG.
The configuration of the laser recording device 10A according to the first embodiment will be described. As shown in the figure, the laser recording device 10A according to the first embodiment includes an odd number of semiconductor lasers LD of 3 or more (15 in the present embodiment) each of which emits a laser beam, and each semiconductor laser. An exposure head 12 that collects each laser beam emitted from the LD, a thermal sensitive material T on which an image is recorded, and a drum 14 that is rotationally driven so that the thermal sensitive material T moves in the main scanning direction. And a sub-scanning motor 16 for rotating the ball screw 18 to move the exposure head 12 arranged on the ball screw 18 in the sub-scanning direction which is a direction orthogonal to the main scanning direction. . In addition,
In this embodiment, as the semiconductor laser LD, an optical fiber coupled semiconductor laser having the intensity distribution shown in FIG. 14 is applied.

On the other hand, the exposure head 12 is provided with a transverse multimode fiber array section 30 for collecting and emitting the laser beams guided from the plurality of semiconductor lasers LD. The emitted laser beams are guided to the fiber array unit 30 by the transverse multimode optical fibers 20. In this embodiment, in order to make the laser beam have a high output,
A multimode optical fiber having a relatively large core diameter is used as the optical fiber 20.

FIG. 2 shows the fiber array section 30 of FIG.
The configuration when viewed in the direction of arrow B is shown. As shown in the figure, the fiber array unit 30 according to the present embodiment
Is provided with a pair of bases 30A in which a plurality of V-shaped grooves are provided so as to be adjacent to each other in the sub-scanning direction on opposite surfaces, and one optical fiber 20 is fitted into each V-shaped groove. It is configured. Therefore, the plurality of laser beams L emitted from each semiconductor laser LD are emitted from the fiber array unit 30 in two rows in the main scanning direction and at predetermined intervals along the sub scanning direction.

As the light source, each semiconductor laser LD may be one which emits light in a broadband area in one direction. At this time, the laser beam L emitted from each semiconductor laser LD is arranged so that the broadband area direction thereof coincides with the sub-scanning direction.

Further, as shown in FIG. 1, the exposure head 12
The first collimator lens 32A that makes the laser beam L emitted from the fiber array unit 30 into a substantially parallel light flux from the fiber array unit 30 side, the first condensing lens 38A that once condenses the laser beam L, and the array aperture. Plate 39,
The second collimator lens 32B for converting the laser beam L condensed by the first condenser lens 38A into a substantially parallel light beam, the array refracting element 36, and the laser beam L converted into a substantially parallel light beam by the second collimator lens 32B are thermally sensitive materials. T
The second condensing lens 38B that condenses upward is arranged in order.

Further, the exposure head 12 has a rotary shaft shown in FIG.
By rotating in the direction of arrow A, the array refraction element 36
An element moving motor 40 capable of inserting / removing the laser beam into / from the optical path of the laser beam L is provided.

The array refraction element 36 according to the present embodiment.
Are the laser beams L that are respectively incident on each other, as shown in FIG.
A pair of concave lens-shaped deflection angle prisms 36A and deflection angle prisms 36B having a unit surface shape that divide the laser beam L into two are linearly formed so that the division directions of the laser beams L coincide with each other and are along the division directions. It is arranged and configured,
The dividing direction of the laser beam L coincides with the sub-scanning direction, and the element moving motor 40 positions the element so that the laser beam L can be inserted and removed at a position where the second collimator lens 32B forms a far field pattern.

FIG. 4A shows the state of the focused spot formed on the thermal sensitive material T by the second focusing lens 38B when the array refracting element 36 is not positioned on the optical path of the laser beam L. 4B shows states of condensed spots formed on the thermal sensitive material T when the array refracting element 36 is positioned on the optical path of the laser beam L, respectively. It should be noted that the array aperture plate 39 described later shields a predetermined region at both ends in the sub-scanning direction of each laser beam L, so that each focused spot has a state in which both ends in the sub-scanning direction are cut. For the sake of simplicity, each focus spot is shown as a circle.

As shown in FIG. 4 (A), when the array refracting element 36 is not positioned on the optical path of the laser beam L, the laser beam L emitted from each optical fiber 20.
Form a focused spot on the thermal sensitive material T without being divided. However, when the array refracting element 36 is positioned on the optical path of the laser beam L, as shown in FIG. Each laser beam L will be divided into two along the sub-scanning direction, and two focused spots will be formed on the thermal sensitive material T for each laser beam L.

That is, in the laser recording apparatus 10A according to this embodiment, the array refraction element 36 is moved to the laser beam L.
By selectively switching whether or not it is positioned on the optical path, the image to be recorded on the thermal sensitive material T is switched to a predetermined resolution or a resolution higher than the predetermined resolution.

In the present embodiment, as shown in FIG. 4A, when the array refracting element 36 is not located on the optical path of the laser beam L, that is, when image formation is performed on the high resolution side. The interval between the converging spots adjacent to each other in the sub-scanning direction is set to 4 · ε, and the other spots are formed so that the condensing spots of the other rows are formed at the central position in the sub-scanning direction between the converging spots adjacent to each other in the sub-scanning direction. Is configured. Thus, an image having a scanning line pitch interval of 2 · ε can be recorded on the thermal sensitive material T by one main scan.

As shown in FIG. 4B, in the present embodiment, the shift amount of the focused spot on the thermal sensitive material T corresponding to the two laser beams separated by the array refracting element 36 is ε. The relevant parts are set so that

On the other hand, FIG. 5 shows the array aperture plate 39 shown in FIG.
The configuration when viewed in the direction of arrow C is shown. As shown in the figure, the array aperture plate 39 according to the present embodiment includes
The same number of rectangular openings 39A as the semiconductor laser LD are provided.

The array aperture plate 39 has a first condenser lens 38.
It is arranged at the first condensing position (see also FIG. 1) which is the condensing position of the laser beam L by A. As shown in FIG. Each of the plurality (in the present embodiment, “15”) of laser beams L emitted from each semiconductor laser LD and emitted from the fiber array unit 30 in the state of being arranged at the converging position is located at both ends in the sub-scanning direction. The size and arrangement position are such that a predetermined area can be shielded from light.

The array aperture plate 3 according to the present embodiment.
In FIG. 9, as shown in FIG. 6 and FIG.
The distance from the center of the laser beam L, which corresponds to a half (ΔS / 2) of the center-to-center distance ΔS of the focused spot SP of the laser beam L divided by the array refracting element 36 on the thermal sensitive material T, is subordinate. This is a region outside the straight line in the main scanning direction (broken line in FIG. 6) that is in contact with each of the two positions that are separated from each other in the scanning direction.

As a result, the overlapping area of the laser beam L divided by the array refracting element 36 on the thermal sensitive material T is almost eliminated, and the optical power in this area can be minimized, resulting in ablation. Can be almost certainly prevented.

The center-to-center distance ΔS is derived by computer simulation in this embodiment. Further, each opening 39A of the array opening plate 39 is formed by etching in this embodiment.

Next, the configuration of the control system of the laser recording apparatus 10A according to the present embodiment will be described with reference to FIG. As shown in the figure, the control system includes an LD drive circuit 54 that drives the semiconductor laser LD according to image data,
An element movement motor drive circuit 56 that drives the element movement motor 40, a sub-scanning motor drive circuit 58 that drives the sub-scanning motor 16, an LD drive circuit 54, an element movement motor drive circuit 56, and a sub-scanning motor drive circuit 58 are controlled. And a control circuit 52 that operates. Here, in the control circuit 52,
Image data showing an image to be recorded on the thermal sensitive material T and resolution data showing the resolution of image recording are supplied.

The semiconductor laser LD is the first light source of the present invention.
The optical system configured by the collimator lens 32A and the first condensing lens 38A is the first optical system of the present invention, and the optical system configured by the second collimator lens 32B and the second condensing lens 38B is the second optical system of the present invention. In the optical system, the array refracting element 36 serves as the light splitting means of the present invention, and the array aperture plate 39.
Corresponds to the light shielding means of the present invention, the element moving motor 40 corresponds to the moving means of the present invention, and the thermal sensitive material T corresponds to the recording medium of the present invention.

Next, the operation of the laser recording apparatus 10A constructed as described above will be described with reference to the flowchart shown in FIG.

First, the operator inputs the resolution data indicating the resolution S of the image to be recorded in the laser recording device 10A (step 100). The resolution data and the image data of the image to be recorded are supplied to the control circuit 52,
The control circuit 52 outputs a signal adjusted based on these data to the LD drive circuit 54 and the element movement motor drive circuit 56.
And to the sub-scanning motor drive circuit 58. In the present embodiment, K0 (dpi) and 2 are used as the resolution S.
The following description will be given on the assumption that an image can be recorded at two kinds of resolutions of K0 (dpi).

The resolution input by the operator is 2 · K.
If 0 (dpi) (if affirmative determination is made in step 102), the element moving motor drive circuit 56 drives the element moving motor 40 to prevent the array refracting element 36 from being located on the optical path of the laser beam L. The refraction element 36 is moved (step 104). Further, in this case, the sub-scanning motor drive circuit 58 sets the feeding interval W of the exposure head 12 by the sub-scanning motor 16 in the sub-scanning direction as follows (step 106).

[0076]

[Equation 5]

However, N is the number of semiconductor lasers LD ('15' in this embodiment).

That is, when the resolution is 2 · K0 (dpi), the array refracting element 36 is removed from the optical path of the laser beam L so that the laser beam L is not divided in the sub-scanning direction. The resolution is twice as high as when the laser beam L is split.

When the movement of the array refracting element 36 and the setting of the feed interval in the sub-scanning direction are completed as described above, L
Based on the image data, the D drive circuit 54 controls the drive of each semiconductor laser LD so that the light emission amount corresponds to the data set according to the recording density (step 10).
8).

The laser beam L emitted from each semiconductor laser LD is converted into a substantially parallel light flux by the first collimator lens 32A, and then the first collimator lens 38A makes the first beam.
It is focused at the focus position. Then, the condensed laser beam L diverges through the array aperture plate 39 at the first condensing position as a boundary, and the diverged laser beam L
After being converted into a substantially parallel light flux by the second collimator lens 32B, the light is focused on the thermal sensitive material T of the drum 14 by the second condenser lens 38B.

In this case, on the thermal sensitive material T, beam spots S1 to S1 each having an intensity distribution shown in FIG.
S15 (FIG. 10 (A)) is formed. As shown in FIG. 10A, the beam spots S1 to S15 are transmitted by the exposure head 12 in the sub-scanning direction at a pitch of the feeding interval W, and the drum 14 is rotated in the main scanning direction, so that the resolution is increased. A two-dimensional image having a value of 2.K0 (dpi) is formed on the thermal sensitive material T (step 110).

Next, the resolution is from 2 · K0 (dpi) to K.
A case where it is changed to 0 (dpi) (when a negative determination is made in step 102) will be described. In this case, the element moving motor drive circuit 56 drives the element moving motor 40,
The array refracting element 36 is moved so that the array refracting element 36 is located on the optical path of the laser beam L (step 1).
12). Further, in this case, the sub-scanning motor drive circuit 58 sets the feed interval W ′ in the sub-scanning direction of the exposure head 12 by the sub-scanning motor 16 as follows (step 1).
14).

[0083]

[Equation 6]

That is, when the resolution is K0 (dpi), by arranging the array refracting element 36 on the optical path of the laser beam L, a plurality of laser beams L incident on the array refracting element 36 in the sub-scanning direction ( In the present embodiment, the laser beam is divided into '2') laser beams.
It realizes a resolution of one-half.

When the movement of the array refracting element 36 and the setting of the feed interval in the sub-scanning direction are completed as described above, L
The D drive circuit 54 controls the drive of each semiconductor laser LD based on the image data so that the amount of light emission is in accordance with the data set according to the recording density (step 11).
6).

The laser beam L emitted from each semiconductor laser LD is converted into a substantially parallel light flux by the first collimator lens 32A, and then the first collimator lens 38A passes the first beam.
The light is condensed at the light collecting position in the same state as that shown in FIG.

At the first focus position, the array aperture plate 39 shields a predetermined region at each end of each laser beam L in the sub-scanning direction.

Then, the laser beam L in the state where the predetermined region is shielded is diverged at the first condensing position as a boundary,
After being made into a substantially parallel light flux by the second collimator lens 32B, it is supplied to the array refraction element 36 and is divided into four in the sub-scanning direction for each laser beam L (beam sharing).
To be done. Then, the four-divided laser beam is transferred onto the thermal sensitive material T via the second condenser lens 38B, as shown in FIG.
As shown in (B), each laser beam is condensed in a state of being divided into two.

That is, as shown in FIG. 11A, the array refracting element 36 is provided at a position where the laser beam L on the optical axis of each laser beam L becomes a substantially parallel light beam and in the vicinity of a position where a far field pattern can be formed. Figure 11 when placed
As shown in FIG. 11B, each laser beam L is once divided into four by the array refraction element 36, and each laser beam L divided into four by the array refraction element 36 is shown in FIG. 11A. By being condensed by the second condensing lens 38B, the thermal condensing material T is superposed two by two in the sub-scanning direction, and as a result, is divided into two.

At this time, one focused spot is formed by the focused beams of the number of array pairs of the array refracting element 36, so that when the laser beam incident side is viewed from the focal position (the position of the thermal sensitive material T). And when the emission side of the laser beam is seen from the focus position, the blur direction of each laser beam becomes symmetrical with respect to the optical axis direction, and as a result, the quality of the recorded image in the laser recording device 10A can be improved. it can.

Further, in each of the focused spot pairs formed on the thermal sensitive material T, a predetermined area at both ends of the laser beam L in the sub-scanning direction is array aperture plate before the laser beam L is divided by the array refraction element 36. Since the laser beam L divided by the array refraction element 36 is shifted in the center position on the thermal sensitive material T and a part of the laser beam L is superposed, the area of the superposed region becomes small. The optical power in this region can be reduced, and as a result, the occurrence of ablation can be prevented.

That is, the intensity distribution by the focused spot pair formed on the thermal sensitive material T by the laser beam L divided by the array refracting element 36 when the array aperture plate 39 is not used is shown in FIG. ), The intensity distributions of the respective focused spots SP are combined in the sub-scanning direction, and the intensity of each focused spot is added to the overlapping region of the focused spots SP. The intensity of the focused spot pair in the central portion in the sub-scanning direction is significantly higher than the maximum level of each focused spot SP.

On the other hand, when the array aperture plate 39 is used, the intensity distribution by the focused spot pair formed on the thermal sensitive material T by the laser beam L divided by the array refraction element 36 is shown in FIG. As shown in (B), the intensity distributions of the respective focused spots SP are combined in the sub-scanning direction, but the overlapping region of the focused spots SP is the laser beam that is the source of each focused spot. Since the predetermined areas at both ends of L in the sub-scanning direction are shielded by the array aperture plate 39, the intensity at the central portion of the focused spot pair in the sub-scanning direction is set to each focus spot SP.
Can be suppressed to about the maximum level, and as a result, the occurrence of ablation can be almost certainly prevented.

In this case, on the thermal sensitive material T, as an example, beam spots S1 'to S15' (FIG. 10 (B)) having the intensity distribution in the state shown in FIG. 12 (B) are formed.

The beam spots S1 'to S15' are
As shown in FIG. 10B, the exposure head 12 is fed in the sub-scanning direction at a feed interval W ′ and the drum 1
4 is rotated in the main scanning direction so that the resolution is K0.
A two-dimensional image of (dpi) is formed on the thermal sensitive material T (step 110).

In this way, the resolution of the recorded image is set to 2 · K0.
When (dpi) is changed to K0 (dpi), the beam spots S1 to S15 are changed to beam spots S1 ′ simply by inserting the array refracting element 36 in the optical path of the laser beam L.
To S15 ', the image can be recorded at high speed because the sub-scanning speed is increased.

Similarly, the resolution can be changed from K0 (dpi) to 2.K0 (dpi).

The processing of step 100 corresponds to the input means of the present invention.

As described in detail above, in the laser recording apparatus 10A according to the first embodiment, the semiconductor laser LD
The laser beam L emitted from the fiber array unit 3
0 and the thermal sensitive material T are once focused, and the focused laser beam L is focused on the thermal sensitive material T.
The array refraction element 36 arranged between the first condensing position and the thermal sensitive material T divides the laser beam L into two in the sub-scanning direction, and the array aperture arranged at the first condensing position. Since the plate 39 shields a predetermined region at the end of the laser beam L in the sub-scanning direction, the laser beam L divided by the array refracting element 36 is shifted in the center position on the thermal sensitive material T and a part thereof is overlapped. In this case, since the area of the overlapping region is small, the optical power of this region can be reduced, and as a result, the occurrence of ablation can be prevented.

Further, in the laser recording apparatus 10A according to the first embodiment, the predetermined region is collected from the center of the laser beam L on the thermal sensitive material T of the laser beam L divided by the array refracting element 36. Ablation occurs because the area outside the straight line in the main scanning direction is in contact with each of the two positions that are separated from each other on both ends in the sub scanning direction by a distance corresponding to a predetermined range including half the distance between the centers of the light spots. Can be almost certainly prevented.

In the present embodiment, the case where the concave refraction prism 36A and the deflection prism 36B are arranged as the array refracting element 36 is applied, but the present invention is not limited to this. However, the present invention is not limited to this, and any one can be applied as long as the refracting members having a unit surface shape that divides one light beam into two are arranged in pairs in an array. can do.

FIG. 13 shows an example (plan view) of an array refracting element having a shape other than the array refracting element 36 shown in the present embodiment. The array refraction element shown in FIG. 13A is configured by forming a pair of unit surface shapes that are convex toward the laser beam emission side in a linear shape along the sub-scanning direction. The array refracting element shown in FIG. 13B has a surface formed to be parallel to the laser beam incident side in the optical axis direction of the laser beam and one end of the surface on the laser beam incident side. Formed by forming a pair of unit surface shapes, which are a combination of the surfaces formed so as to incline with respect to the optical axis direction of the laser beam from the section, in a straight line along the sub-scanning direction Is. Further, the array refracting element shown in FIG.
A surface formed so as to be parallel to the optical axis direction of the laser beam with respect to the emission side of the laser beam, and an inclination from the one end of the surface on the laser beam incident side with respect to the optical axis direction of the laser beam. The unit surface shape, which is a combination of the formed surface and the respective surfaces, is formed in a linear shape along the sub-scanning direction. Note that FIG. 13B
In the array refracting element shown in FIG. 13, the unit surface shape is convex toward the laser beam incident side, and FIG.
In the array refracting element shown in (C), the unit surface shape is concave with respect to the laser beam emitting side.

It goes without saying that an array refraction element integrally formed to have the same shape as the array refraction element 36 according to the present embodiment can also be applied.

Even when these array refracting elements are applied, the same effects as in the present embodiment can be obtained.

[Second Embodiment] In the first embodiment,
The case where the array refracting element of the present invention is arranged at a site where light becomes a substantially parallel light flux and the incident light is divided into different angles and emitted is described. However, in the second embodiment, A description will be given of a mode in which the array refraction element is arranged at a portion where light is converged, and the incident light is divided and emitted so as to be substantially parallel to each other.

First, the structure of the laser recording apparatus 10B according to the second embodiment will be described with reference to FIG. Incidentally, the laser recording device 10A shown in FIG.
The same components as in FIG. 1 are assigned the same reference numerals as those in FIG. 1 and their description is omitted.

As shown in the figure, in the laser recording apparatus 10B according to the second embodiment, an array refraction element 36 'is used in place of the array refraction element 36, and an array refraction element 36' is provided as a second refraction element. The difference from the laser recording apparatus 10A according to the first embodiment described above is that the laser beam L is arranged between the condenser lens 38B and the thermal sensitive material T at a position where the laser beam L converges.

Array refraction element 3 according to the second embodiment
As shown in FIG. 16B, 6'denotes a unit surface shape that splits each incident laser beam L into two and emits the two split laser beams so as to be substantially parallel to each other. A pair of refraction members included in the laser beam L are formed linearly so that the division directions of the laser beams L coincide with each other and the division directions of the laser beam L are in the sub-scanning direction. Positioning is performed by the element moving motor 40 so as to match.

When the resolution is set to K0 (dpi), the laser beam L emitted from each semiconductor laser LD is converted into a substantially parallel light beam by the first collimator lens 32A and then supplied to the first condenser lens 38A. Being the first
The light is condensed at the light collecting position in the same state as that shown in FIG.

On the other hand, at the first focus position, the array aperture plate 3
A predetermined area at both ends of each laser beam L in the sub-scanning direction is shielded by 9.

Then, the laser beams L in the state where the predetermined regions at both ends in the sub-scanning direction are shielded are diverged at the first converging position as a boundary, and after being made into a substantially parallel light beam by the second collimator lens 32B. , The array refraction element 36 ′ is arranged via the second condenser lens 38B as shown in FIG.
And is divided into four in the sub-scanning direction for each laser beam L as shown in FIG. 16B (beam sharing).
At the same time, the two divided laser beams are emitted from each of the pair of portions corresponding to the unit surface shape of the array refraction element 36 ′ so as to be parallel to each other. The laser beam divided into four parts is used as the thermal sensitive material T.
Two laser beams are superposed on each other in the sub-scanning direction, and as a result, each laser beam L is condensed into two beams.

At this time, since one focused spot is formed by the focused beams of the number of array pairs of the array refracting element 36 ', the laser beam incident side is viewed from the focal position (the position of the thermal sensitive material T). At this time and when the emission side of the laser beam is viewed from the focus position, the blur direction of each laser beam becomes symmetrical with respect to the optical axis direction, and as a result, the image quality of the recorded image in the laser recording device 10B is improved. You can

Further, in each of the focused spot pairs formed on the thermal sensitive material T, a predetermined area at both ends in the sub-scanning direction of the laser beam L is arrayed before the array refraction element 36 'divides the laser beam L. Since it is shielded by the plate 39, the area of the overlapping region becomes small when the laser beam L divided by the array refracting element 36 'is partially overlapped on the thermal sensitive material T by shifting the center position. Therefore, the optical power in this region can be reduced, and as a result, the occurrence of ablation can be prevented.

In this case, on the thermal sensitive material T, as an example, beam spots S1 'to S15' (FIG. 10B) having the intensity distribution in the state shown in FIG. 12B are formed.

The beam spots S1 'to S15' are
As shown in FIG. 10B, the exposure head 12 is fed in the sub-scanning direction at a feed interval W ′ and the drum 1
4 is rotated in the main scanning direction so that the resolution is K0.
A two-dimensional image of (dpi) is formed on the thermal sensitive material T.

On the other hand, when forming an image having a resolution of 2 · K0 (dpi), the array refracting element 36 ′ is moved so as not to be located on the optical path of the laser beam L, and the arrangement shown in FIG.
It may be controlled so as to obtain the beam spots S1 to S15 shown in (A).

As described above in detail, in the laser recording apparatus 10B according to the second embodiment, the semiconductor laser LD
The laser beam L emitted from the fiber array unit 3
0 and the thermal sensitive material T are once focused, and the focused laser beam L is focused on the thermal sensitive material T.
An array that divides the laser beam L into two in the sub-scanning direction by the array refraction element 36 'arranged between the first condensing position and the thermal sensitive material T and is arranged at the first condensing position. Since the aperture plate 39 shields a predetermined region at the end of the laser beam L in the sub-scanning direction, the array refraction element 3
The laser beam L divided by 6'is applied to the thermal sensitive material T
Since the area of the overlapping region becomes small when the center position is shifted and the portions are overlapped with each other, the optical power in this region can be reduced, and as a result, the occurrence of ablation can be prevented.

Further, in the laser recording apparatus 10B according to the second embodiment, the above-mentioned predetermined region is divided from the center of the laser beam L by the array refracting element 36 'on the thermal sensitive material T. Since the area outside the straight line in the main scanning direction is in contact with each of the two positions separated by the distance in the sub-scanning direction at both ends corresponding to the distance in the predetermined range including half the distance between the centers of the focused spots, The occurrence can be almost certainly prevented.

On the other hand, in the laser recording devices 10A and 10B according to each of the above-described embodiments, the array refracting element is provided between the fiber array section 30 and the thermal sensitive material T, and the laser beam splitting direction is broad. Since the laser beam is arranged so as to be parallel to the area direction, the blur direction of the laser beam at a position deviated from the focus position of the laser beam forward and backward in the optical axis direction (depth direction) is symmetrical with respect to the optical axis direction. As a result, the image quality of the recorded image can be improved, and the array refraction element can be constructed at a lower cost as compared with the case where a uniaxial crystal is used. Can be configured at cost.

Further, in the laser recording devices 10A and 10B according to each of the above embodiments, since the array refracting element is arranged at the position where the far field pattern of the laser beam can be formed, the laser beam emitted from each semiconductor laser LD is The array refractive element can be similarly acted on all of L.

Further, in the laser recording apparatuses 10A and 10B according to the above-described respective embodiments, resolution information indicating the resolution of an image formed on the thermal sensitive material T by scanning exposure (corresponding to "resolution data" in the above-described respective embodiments). .), And the resolution indicated by the resolution information is a predetermined first resolution (2.K0 (dp in the above embodiments).
i)), the array refraction element is a semiconductor laser LD.
The second resolution, which is retracted from the optical axis of the laser beam emitted from the device, and whose resolution indicated by the resolution information is lower than the first resolution (K0 (dp
In the case of i)), since the array refraction element is moved so that it is located on the optical axis,
The resolution at the time of recording an image on the thermal sensitive material T can be easily changed only by inputting the resolution information.

In the second embodiment described above, the case where the array refraction element 36 'is arranged at the portion where the laser beam is focused has been described. However, the present invention is not limited to this. The beam may be diverged, that is, it may be arranged between the first condensing position and the second collimator lens 32B. Also in this case, the same effect as that of the second embodiment can be obtained.

[Third Embodiment] First, the configuration of a laser recording apparatus 10C according to a third embodiment will be described with reference to FIG. In the figure, the same components as those of the laser recording apparatus 10A shown in FIG. 1 are designated by the same reference numerals as those in FIG. 1 and their explanations are omitted.

As shown in the figure, the laser recording apparatus 10C according to the third embodiment is different from the first embodiment only in that a polarization direction control element 34 and a polarization separation element 37 are used instead of the array refraction element 36. Laser recording apparatus 1 according to one embodiment
It is different from 0A.

The polarization separation element 37 according to the present embodiment is
As shown in FIG. 18, the laser beam L, which is formed by bonding two uniaxial crystals 37A and 37B whose crystal optical axes are orthogonal to each other, is separated into an ordinary ray and an extraordinary ray with respect to the sub-scanning direction of the thermal sensitive material T. A uniaxial crystal 37A arranged on the incident side of the laser beam L, the crystal optical axis of which is set parallel to the optical axis of the laser beam L, and which is arranged on the emission side of the laser beam L. The crystal optical axis of the crystalline film 37B is set in a direction orthogonal to the optical axis of the laser beam L and the sub-scanning direction. In this case, the ordinary ray goes straight through the polarization separation element 37, and the extraordinary ray is refracted in the sub-scanning direction by the polarization separation element 37.

As the polarization separation element 37, the crystal optical axis of the uniaxial crystal 37A is set to be orthogonal to the optical axis of the laser beam L and parallel to the sub-scanning direction.
A Wollaston prism in which the crystal optical axis of B is set in a direction orthogonal to the optical axis of the laser beam L and the sub-scanning direction may be applied.

Further, the polarization separation element 37 does not necessarily have to separate the laser beam L into an ordinary ray and an extraordinary ray, and may be any one that separates the laser beam L into two rays having different polarization directions.

On the other hand, as shown in FIGS. 19 (A) and 19 (B), the polarization direction control element 34 according to the present embodiment has a glass plate 34B as a base, and an optical axis direction of the polarization separation element 37. When provided on the upstream side, a part of the laser beam L is transmitted and the crystal optical axis is inclined by about 45 degrees with respect to the polarization direction of the light separated by the polarization separation element 37. It is configured by disposing a wave plate 34A. Further, here, a plurality of ½ wavelength plates 34A are arranged at predetermined intervals D so that the area ratio of the light incident regions of the ½ wavelength plate 34A and the glass plate 34B is approximately 1: 1. Both ends (portions through which the laser beam L does not pass) of each are bonded to the glass plate 34B.

As described above, the polarization direction control element 34 according to the present embodiment has the laser beam L of the half-wave plate 34A.
Of the laser beam L not incident on the half-wave plate 34A, that is, the glass plate 34.
The area ratio to the region where the laser beam L of B is incident is about 1
A plurality of half-wave plates 34A are arranged at predetermined intervals D in the entire incident region of the laser beam L so as to be paired with one another. However, based on the device specifications of the laser recording device 10C and the like. Then, the area ratio of the regions of the half-wave plate 34A and the glass plate 34B on which the laser beam L is incident is
The two light beams of the two laser beams obtained by the polarization separation element 37 may be configured to have substantially the same light amount. Further, the laser beam L that has passed through the half-wave plate 34A and the laser beam L that has not passed therethrough (that is, the laser beam L that has transmitted only the glass plate 34B).
It is also possible to adjust the arrangement position of the half-wave plate 34A so that the light amounts of the two are substantially the same. Since the configurations of these polarization direction control elements are substantially the same as those shown in FIG. 19, other illustrations of these polarization direction control elements are omitted.

Here, the case where the polarization direction control element 34 configured as described above is not used, and the case where the polarization direction control element 34 is used
The separation state of the laser beam by the polarization separation element 37 in the case of using will be described. First, referring to FIG. 20, the separation state of the laser beam when the polarization direction control element 34 is not used will be described.

As shown in FIG. 20A, for example, when a laser beam having a polarization of e1 + e2 (a laser beam having a polarization inclined by 45 degrees with respect to the polarization e1) is incident on the polarization separation element 37, the light beams are evenly distributed. It is separated into two polarized lights e1 and e2.

On the other hand, as shown in FIG.
When the laser beam of No. 1 is incident on the polarization separation element 37, only the laser beam of polarized light e1 is emitted from the polarization separation element 37. Therefore, in this case, it is difficult to evenly separate the two laser beams.

Next, referring to FIG. 21, the separation state of the laser beam when the polarization direction control element 34 is used will be described.

As shown in FIG. 21A, the polarized light is e1 +
When the laser beam of e2 (the laser beam of the polarized light inclined by 45 degrees with respect to the polarized light e1) is incident on the glass plate 34B, it is transmitted without changing the polarization direction, and this laser beam is incident on the polarization separation element 37. Thus, the two polarized lights e1 and e2 are evenly separated. On the other hand, the polarized light is e
When the 1 + e2 laser beam is incident on the ½ wavelength plate 34A, the crystal optical axis is inclined by 45 degrees with respect to the polarized light e1, so that the laser beam is transmitted without changing the polarization direction, and this laser beam is polarized and separated. The light enters the element 37 and is equally divided into two polarized lights e1 and e2.

On the other hand, as shown in FIG.
When the laser beam of No. 1 is incident on the glass plate 34B,
The laser beam is transmitted without changing the polarization direction, enters the polarization separation element 37, and emits the laser beam of only the polarized light e1. On the other hand, when the laser beam of the polarized light e1 is incident on the half-wave plate 34A, the crystal optical axis is inclined by 45 degrees with respect to the polarized light e1 and is emitted as the polarized light e2 orthogonal to the polarized light e1. Then, this laser beam enters the polarization separation element 37 and emits a laser beam of only the polarized light e2. Therefore, although the positions are spatially different, it is possible to divide the laser beam evenly as a whole.

The configuration of the control system of the laser recording apparatus 10C according to the present embodiment is the same as that of the laser recording apparatus 10A according to the first embodiment (see FIG. 8), and the description thereof is omitted here. To do. The optical system configured by the polarization direction control element 34 and the polarization separation element 37 corresponds to the light splitting means of the present invention.

Next, the operation of the laser recording apparatus 10C configured as described above will be described with reference to the flowchart shown in FIG.

First, the operator inputs resolution data indicating the resolution of an image to be recorded in the laser recording device 10C (step 200). The resolution data and the image data of the image to be recorded are supplied to the control circuit 52, and the control circuit 52 outputs the signals adjusted based on these data to the LD drive circuit 54, the element movement motor drive circuit 56 and the sub-scanning. It is supplied to the motor drive circuit 58. In the present embodiment, the resolutions R (dpi) and 2 · R are
The following description will be made assuming that an image can be recorded at two types of resolutions (dpi).

The resolution input by the operator is 2 · R.
If it is (dpi) (if affirmative determination is made in step 202), the element moving motor drive circuit 56 drives the element moving motor 40, and the polarization separation element 37 is polarized and separated so that it is not located on the optical path of the laser beam L. The element 37 is moved (step 204). In this case, the sub-scanning motor drive circuit 58 controls the exposure head 12 by the sub-scanning motor 16.
The feed interval W in the sub-scanning direction is set as in the above equation (1) (step 206).

That is, when the resolution is 2.multidot.R (dpi), the polarization beam splitting element 37 is removed from the optical path of the laser beam L to move the laser beam L to 2 in the sub-scanning direction.
The two laser beams (the ordinary ray and the extraordinary ray) are not separated from each other, thereby achieving a resolution twice as high as that when separating the laser beam L.

When the movement of the polarization separation element 37 and the setting of the feed interval in the sub-scanning direction are completed as described above, the LD
The drive circuit 54 controls each semiconductor laser L according to the image data.
The drive of D is controlled (step 208).

The laser beam L emitted from each semiconductor laser LD is converted into a substantially parallel light flux by the first collimator lens 32A, and then the first collimator lens 38A passes the first beam.
It is focused at the focus position.

Then, the condensed laser beam L diverges after passing through the array aperture plate 39 at the first condensing position as a boundary, and the diverged laser beam L becomes the second laser beam L.
The collimator lens 32 </ b> B collimates the light into a substantially parallel light flux, which then enters the polarization direction control element 34. The laser beam L incident on the polarization direction control element 34 is emitted without changing the polarization direction of the laser beam incident on the glass plate 34B. Regarding the laser beam incident on the half-wave plate 34A, the polarization direction of the polarized light whose polarization direction coincides with the crystal optical axis of the half-wave plate 34A is not changed and the polarization direction is the crystal optical axis. The polarized light that does not coincide with is emitted with its polarization direction changed to a direction corresponding to the angle formed by the polarization direction and the crystal optical axis.

The laser beam L emitted from the polarization direction control element 34 is condensed on the thermal sensitive material T via the second condenser lens 38B.

In this case, on the thermal sensitive material T, the beam spots S1 to S1 each having the intensity distribution shown in FIG.
S15 (FIG. 10 (A)) is formed. As shown in FIG. 10A, the beam spots S1 to S15 are transmitted by the exposure head 12 in the sub-scanning direction at a pitch of the feeding interval W, and the drum 14 is rotated in the main scanning direction, so that resolution A two-dimensional image of 2 · R (dpi) is formed on the thermal sensitive material T (step 210).

Next, the resolution is changed from 2 · R (dpi) to R.
The case where it is changed to (dpi) (when a negative determination is made in step 202) will be described. In this case, the element moving motor drive circuit 56 drives the element moving motor 40 to move the polarization separating element 37 so that the polarization separating element 37 is located on the optical path of the laser beam L (step 21).
2). Further, in this case, the sub-scanning motor drive circuit 58 sets the feed interval W ′ of the exposure head 12 by the sub-scanning motor 16 in the sub-scanning direction as in the above equation (2) (step 214).

That is, when the resolution is R (dpi), the laser beam L incident on the polarization beam splitting element 37 is divided into two in the sub-scanning direction by positioning the polarization beam splitting element 37 on the optical path of the laser beam L. The laser beam (ordinary ray and extraordinary ray) is separated, and this realizes a resolution that is half that of the case where the laser beam L is not separated.

When the movement of the polarization separation element 37 and the setting of the feed interval in the sub-scanning direction are completed as described above, the LD
The drive circuit 54 controls each semiconductor laser L according to the image data.
The drive of D is controlled (step 208).

The laser beam L emitted from each semiconductor laser LD is converted into a substantially parallel light flux by the first collimator lens 32A, and then the first collimator lens 38A passes the first beam.
The light is condensed at the light collecting position in the same state as that shown in FIG.

On the other hand, at the first focus position, the array aperture plate 3
A predetermined area at both ends of each laser beam L in the sub-scanning direction is shielded by 9. Then, the laser beams L in a state where the predetermined regions at both ends in the sub-scanning direction are shielded are diverged at the first condensing position as a boundary, and the second collimator lens 32 is provided.
After being made into a substantially parallel light flux by B, the polarization direction control element 3
It is incident on 4.

The laser beam L incident on the polarization direction control element 34 is emitted without changing the polarization direction of the laser beam incident on the glass plate 34B. Regarding the laser beam incident on the half-wave plate 34A, the polarization direction of the polarized light whose polarization direction coincides with the crystal optical axis of the half-wave plate 34A is not changed and the polarization direction is the crystal optical axis. The polarized light that does not coincide with is emitted with its polarization direction changed to a direction corresponding to the angle formed by the polarization direction and the crystal optical axis.

The laser beam L emitted from the polarization direction control element 34 is supplied to the polarization separation element 37, and both ordinary and extraordinary rays are transmitted. Then, the ordinary ray and the extraordinary ray are collected on the thermal sensitive material T via the second condenser lens 38B in a state of being divided into two for each laser beam as shown in FIG. 4B. Be illuminated.

At this time, each of the focused spot pairs formed on the thermal sensitive material T has a predetermined area at both ends in the sub-scanning direction of the laser beam L before the splitting of the laser beam L by the polarization separation element 37. Since the light is shielded by the plate 39, the area of the overlapping region becomes small when the laser beam L divided by the polarization separation element 37 is partially overlapped with the center position shifted on the thermal sensitive material T. The optical power in this region can be reduced, and as a result, the occurrence of ablation can be prevented.

In this case, on the thermal sensitive material T, as an example, beam spots S1 'to S15' (FIG. 10B) having the intensity distribution in the state shown in FIG. 12B are formed.

The beam spots S1 'to S15' are
As shown in FIG. 10B, the exposure head 12 is fed in the sub-scanning direction at a feed interval W ′ and the drum 1
By rotating 4 in the main scanning direction, the resolution is R
A two-dimensional image of (dpi) is formed on the thermal sensitive material T (step 210).

As described above, the resolution of the recorded image is set to 2 · R.
When (dpi) is changed to R (dpi), the beam spots S1 to S15 are changed to beam spots S1 'to S1 only by inserting the polarization separation element 37 in the optical path of the laser beam L.
The image can be easily enlarged to 15 'and the sub-scanning speed is increased, so that image recording can be performed at high speed.

Similarly, the resolution is changed from R (dpi) to 2
-It can be changed to R (dpi). The process of step 200 corresponds to the input means of the present invention.

As described in detail above, in the laser recording apparatus 10C according to the third embodiment, the semiconductor laser LD
The laser beam L emitted from the fiber array unit 3
0 and the thermal sensitive material T are once focused, and the focused laser beam L is focused on the thermal sensitive material T.
The laser beam L is divided into two in the sub-scanning direction by the polarization direction control element 34 and the polarization separation element 37 arranged between the first focus position and the thermal sensitive material T, and the first focus position Since a predetermined area at the end of the laser beam L in the sub-scanning direction is shielded by the array aperture plate 39 disposed at the thermal aperture T, the laser beam L split by the polarization direction control element 34 and the polarization separation element 37 is transferred to the thermal sensitive material T. Since the area of the overlapping region becomes small when the center position is shifted and the portions are overlapped with each other, the optical power in this region can be reduced, and as a result, the occurrence of ablation can be prevented.

Further, in the laser recording apparatus 10C according to the third embodiment, the thermal sensitivity of the laser beam L obtained by dividing the predetermined region from the center of the laser beam L by the polarization direction control element 34 and the polarization separation element 37. As an area outside the straight line in the main scanning direction that is in contact with each of the two positions separated on the both end sides in the sub scanning direction by a distance corresponding to a distance in a predetermined range including half the distance between the centers of the focused spots on the material T. Therefore, the occurrence of ablation can be almost certainly prevented.

[Fourth Embodiment] In the third embodiment,
A mode in which the polarization separation element of the present invention is arranged at a site where light becomes a substantially parallel light flux and two lights are emitted at different angles has been described. However, in the fourth embodiment, polarization separation is performed. One mode in which the element is arranged at a site where the light diverges and two lights are emitted from different positions in the direction of light separation by the polarization separation element will be described.

First, the structure of a laser recording apparatus 10D according to the fourth embodiment will be described with reference to FIG. The laser recording device 10 shown in FIG.
The same components as C are given the same reference numerals as those in FIG. 17,
The description is omitted.

As shown in the figure, the laser recording apparatus 10D according to the fourth embodiment uses a polarization separation element 37 'made of a uniaxial crystal in place of the polarization separation element 37, and controls the polarization direction. The laser recording apparatus 10C according to the third embodiment described above is different in that the element 34 and the polarization separation element 37 'are arranged at the site where the laser beam L diverges between the first focusing position and the second collimator lens 32B. Is different from In this case, the direction of the crystal optical axis of the polarization separation element 37 'is set so as to be between the optical axis direction of the laser beam L and the sub-scanning direction.

When the resolution is set to R (dpi), the laser beam L emitted from each semiconductor laser LD is made into a substantially parallel light flux by the first collimator lens 32A, and then passes through the first condenser lens 38A. Then, the light is focused on the first focus position in the same state as that shown in FIG.

On the other hand, at the first focus position, the array aperture plate 3
A predetermined area at both ends of each laser beam L in the sub-scanning direction is shielded by 9. Then, the laser beams L in a state where the predetermined regions at both ends in the sub-scanning direction are shielded are diverged at the first converging position and supplied to the polarization direction control element 34.

Then, the laser beam L whose polarization direction is controlled by the polarization direction control element 34 is split into an ordinary ray and an extraordinary ray by a polarization splitting element 37 'as shown in FIG. In this case, the polarization separation element 3 for ordinary rays
Since the refractive index of 7'is constant regardless of the direction of the crystal optical axis, it is emitted from the virtual emission point Po on the optical axis of the laser beam L and guided to the second collimator lens 32B. on the other hand,
The refractive index of the polarization beam splitting element 37 'for extraordinary rays differs depending on the incident direction of the laser beam L and the direction of the crystal optical axis, and the crystal optical axis is set between the optical axis direction of the laser beam L and the sub-scanning direction. Therefore, the laser beam L is emitted from the virtual light emitting point Pe displaced by a predetermined amount in the sub-scanning direction from the optical axis of the laser beam L and guided to the second collimator lens 32B.

As a result, the ordinary ray and the extraordinary ray pass through the second collimator lens 32B and the second condenser lens 38B, and are displaced by a predetermined amount in the sub-scanning direction on the thermal sensitive material T, as shown in FIG. 2 for each laser beam as shown in
The beam spots S1 ′ to S15 ′ shown in FIG. 10B are obtained by being condensed in a state of being divided into two. As a result, an image having a resolution of R (dpi) can be formed.

At this time, each condensing spot pair formed on the thermal sensitive material T has both ends in the sub-scanning direction of the laser beam L before the laser beam L is divided by the polarization direction control element 34 and the polarization separation element 37 '. Since a predetermined area of the portion is shielded by the array aperture plate 39, the polarization direction control element 3
4 and the polarization beam splitting element 37 ′ split the laser beam L on the thermal sensitive material T by shifting the center position and partially overlapping the area, the area of the overlapping area becomes small. Therefore, the optical power of this area is reduced. Can be smaller,
As a result, the occurrence of ablation can be prevented.

On the other hand, when an image having a resolution of 2 · R (dpi) is formed, the polarization beam splitting element 37 ′ is set to the laser beam L.
It may be controlled so that the beam spots S1 to S15 shown in FIG.

As described in detail above, in the laser recording apparatus 10D according to the fourth embodiment, the semiconductor laser LD
The laser beam L emitted from the fiber array unit 3
0 and the thermal sensitive material T are once focused, and the focused laser beam L is focused on the thermal sensitive material T.
The laser beam L is divided into two in the sub-scanning direction by the polarization direction control element 34 and the polarization separation element 37 'arranged between the first focus position and the thermal sensitive material T, and
Since the array aperture plate 39 arranged at the condensing position shields a predetermined region at the end of the laser beam L in the sub-scanning direction, the laser beam L split by the polarization direction control element 34 and the polarization splitting element 37 'is divided. Since the area of the overlapping region becomes small when the center position is shifted on the thermal sensitive material T and the portions are overlapped, the optical power of this region can be reduced, and as a result, the occurrence of ablation is prevented. be able to.

Further, in the laser recording apparatus 10D according to the fourth embodiment, the above-mentioned predetermined area is thermally separated from the center of the laser beam L by the polarization direction control element 34 and the polarization separation element 37 '. A region outside a straight line in the main scanning direction which is in contact with each of two positions separated on both end sides in the sub scanning direction by a distance corresponding to a distance in a predetermined range including half the distance between the centers of the focused spots on the photosensitive material T. Therefore, it is possible to almost certainly prevent the occurrence of ablation.

Further, the polarization direction control element 34 according to the third and fourth embodiments is such that the optical axis direction of the laser beam L of the polarization separation element for separating the laser beam L into two laser beams whose polarization directions are orthogonal to each other. In the polarization direction control element provided on the upstream side, when provided on the upstream side in the optical axis direction of the polarization separation element, a part of the laser beam L is transmitted and the light separated by the polarization separation element is transmitted. 1/2 wave plate 3 so that the crystal optical axis is tilted by approximately 45 degrees with respect to the polarization direction
Since 4A is arranged and configured, when used in combination with the polarization separation element, it becomes possible to separate the laser beam L with the same amount of light by the polarization separation element, and in a laser recording apparatus using the polarization separation element. The image quality of the recorded image can be improved.

In the polarization direction control elements 34 according to the third and fourth embodiments, the area where the laser beam L of the half-wave plate 34A is incident and the laser beam which is not incident on the half-wave plate 34A are included. Area L, that is, the glass plate 34
Since the area ratio with respect to the region where the laser beam L of B is directly incident is about 1: 1, the intensity distribution of the separated laser beam can be made uniform.

Further, the polarization direction control elements 34 according to the third and fourth embodiments are constructed by disposing a plurality of ½ wavelength plates 34A at predetermined intervals in the entire incident region of the laser beam L. It can be created easily.

In the laser recording devices 10C and 10D according to the third and fourth embodiments, the polarization direction control element 34 as described above is provided between the semiconductor laser LD and the polarization separation element by the polarization separation element. The crystal optical axis of the half-wave plate 34A is approximately 4 with respect to the polarization direction of the separated laser beam L.
Since the laser beam L is arranged so as to be inclined by 5 degrees, it is possible to separate the laser beam L with an equal amount of light by the polarization separation element, and the image when the image is recorded on the thermal sensitive material T by the separated laser beam L. The image quality of can be improved.

Furthermore, in the laser recording devices 10C and 10D according to the third and fourth embodiments, an element moving motor that moves the polarization separation element so that the polarization separation element is inserted and removed on the optical axis of the laser beam L. Since the element moving motor 40 is provided, the polarization separating element is inserted into and removed from the optical path, so that the resolution at the time of recording an image on the thermal sensitive material T can be easily changed.

The fourth embodiment has been described with respect to the case where the polarization direction control element 34 and the polarization separation element 37 'are arranged at the site where the laser beam diverges, but the present invention is not limited to this. Alternatively, for example, a configuration may be adopted in which the laser beam is arranged to be converged, that is, between the second condenser lens 38B and the thermal sensitive material T. Also in this case, the same effect as that of the fourth embodiment can be obtained.

In the third and fourth embodiments, the case where the element moving motor 40 is configured so that only the polarization separation element can be inserted into and removed from the optical path of the laser beam L has been described. However, the present invention is not limited to this. The present invention is not limited to this, and the element moving motor 40 may be configured so that the polarization direction control element 34 and the polarization separation element can be inserted into and removed from the optical path of the laser beam L at the same time. Also in this case, the same effects as those of the third and fourth embodiments can be obtained.

[Fifth Embodiment] First, the structure of a laser recording apparatus 10E according to the fifth embodiment will be described with reference to FIG. In the figure, the same components as those of the laser recording apparatus 10A shown in FIG. 1 are designated by the same reference numerals as those in FIG. 1 and their explanations are omitted.

As shown in the figure, the laser recording apparatus 10E according to the fifth embodiment is different from the exposure head 12 only in that an exposure head 12 'having a different internal structure is used.
This is different from the laser recording device 10A according to the first embodiment.

Laser recording apparatus 10 according to the fifth embodiment
In the exposure head 12 ′ of E, an array aperture plate 39, a collimator lens 32, an array refracting element 36, and a condenser lens 38 are sequentially arranged from the fiber array section 30 side. Here, the array aperture plate 39 is arranged in the vicinity of the emission port of the laser beam L of the fiber array section 30.

Further, in the exposure head 12 ', the rotation axis rotates in the direction of arrow A in FIG.
An element moving motor 40 capable of inserting / removing 6 on the optical path of the laser beam L and at a position where a far field pattern can be formed by the collimator lens 32 is provided.

Since the configuration of the control system of the laser recording apparatus 10E according to the fifth embodiment is the same as that of the laser recording apparatus 10A according to the first embodiment (see FIG. 8), the description here will be omitted. Omit it.

The array refracting element 36 corresponds to the light splitting means of the present invention, and the optical system constituted by the collimator lens 32 and the condenser lens 38 corresponds to the optical system of the present invention.

Next, the operation of the laser recording apparatus 10E configured as described above will be described with reference to the flowchart shown in FIG.

First, the operator inputs the resolution data indicating the resolution S of the image to be recorded in the laser recording device 10E (step 100). The resolution data and the image data of the image to be recorded are supplied to the control circuit 52,
The control circuit 52 outputs a signal adjusted based on these data to the LD drive circuit 54 and the element movement motor drive circuit 56.
And to the sub-scanning motor drive circuit 58. In the present embodiment, K0 (dpi) and 2 are used as the resolution S.
The following description will be given on the assumption that an image can be recorded at two kinds of resolutions of K0 (dpi).

The resolution input by the operator is 2 · K.
If 0 (dpi) (if affirmative determination is made in step 102), the element moving motor drive circuit 56 drives the element moving motor 40 to prevent the array refracting element 36 from being located on the optical path of the laser beam L. The refraction element 36 is moved (step 104). Further, in this case, the sub-scanning motor drive circuit 58 sets the feeding interval W of the exposure head 12 by the sub-scanning motor 16 in the sub-scanning direction as in the above equation (1) (step 106).

That is, when the resolution is 2 · K0 (dpi), the array refracting element 36 is removed from the optical path of the laser beam L so that the laser beam L is not divided in the sub-scanning direction. The resolution is twice as high as when the laser beam L is split.

When the movement of the array refracting element 36 and the setting of the feed interval in the sub-scanning direction are completed as described above, L
Based on the image data, the D drive circuit 54 controls the drive of each semiconductor laser LD so that the light emission amount corresponds to the data set according to the recording density (step 10).
8).

The laser beam L emitted from each semiconductor laser LD is shielded by the array aperture plate 39 in predetermined regions at both ends in the sub-scanning direction, and is made into a substantially parallel light beam by the collimator lens 32, and then the condenser lens 38. Is focused on the thermal sensitive material T.

In this case, on the thermal sensitive material T, the beam spots S1 to S1 each having an intensity distribution shown in FIG.
S15 (FIG. 10 (A)) is formed. As shown in FIG. 10A, the beam spots S1 to S15 are transmitted by the exposure head 12 in the sub-scanning direction at a pitch of the feeding interval W, and the drum 14 is rotated in the main scanning direction, so that the resolution is increased. A two-dimensional image having a value of 2.K0 (dpi) is formed on the thermal sensitive material T (step 110).

Next, the resolution is from 2 · K0 (dpi) to K.
A case where it is changed to 0 (dpi) (when a negative determination is made in step 102) will be described. In this case, the element moving motor drive circuit 56 drives the element moving motor 40,
The array refracting element 36 is moved so that the array refracting element 36 is located on the optical path of the laser beam L (step 1).
12). Further, in this case, the sub-scanning motor drive circuit 58 sets the feeding interval W ′ of the exposure head 12 by the sub-scanning motor 16 in the sub-scanning direction as in the above equation (2) (step 114).

That is, when the resolution is K0 (dpi), the array refracting element 36 is positioned on the optical path of the laser beam L so that a plurality of laser beams L incident on the array refracting element 36 in the sub-scanning direction ( In the present embodiment, the laser beam is divided into '2') laser beams.
It realizes a resolution of one-half.

When the movement of the array refracting element 36 and the setting of the feed interval in the sub-scanning direction are completed as described above, L
The D drive circuit 54 controls the drive of each semiconductor laser LD based on the image data so that the amount of light emission is in accordance with the data set according to the recording density (step 11).
6).

The laser beam L emitted from each semiconductor laser LD is shielded by the array aperture plate 39 in predetermined regions at both ends in the sub-scanning direction, and the laser beam L in a state in which the predetermined regions are shielded is a collimator lens. After being made into a substantially parallel light flux by 32, the light flux is supplied to the array refraction element 36, and is divided into four (beam sharing) in the sub-scanning direction for each laser beam L. Then, the four-divided laser beam is condensed on the thermal sensitive material T via the condensing lens 38 in a state in which the laser beam is divided into two for each laser beam as shown in FIG. 4B. To be done.

At this time, since one focused spot is formed by the focused beams of the number of array pairs of the array refracting element 36, when the incident side of the laser beam is seen from the focal position (the position of the thermal sensitive material T). And when the laser beam emission side is viewed from the focus position, the blur direction of each laser beam becomes symmetrical with respect to the optical axis direction, and as a result, the quality of the recorded image in the laser recording device 10E can be improved. it can.

Further, in each of the focused spot pairs formed on the thermal sensitive material T, a predetermined area at both ends in the sub-scanning direction of the laser beam L is array aperture plate before the laser beam L is divided by the array refraction element 36. Since the laser beam L divided by the array refraction element 36 is shifted in the center position on the thermal sensitive material T and a part of the laser beam L is superposed, the area of the superposed region becomes small. The optical power in this region can be reduced, and as a result, the occurrence of ablation can be prevented.

That is, the intensity distribution by the focused spot pair formed on the thermal sensitive material T by the laser beam L split by the array refracting element 36 when the array aperture plate 39 is not used is shown in FIG. ), The intensity distributions of the respective focused spots SP are combined in the sub-scanning direction, and the intensity of each focused spot is added to the overlapping region of the focused spots SP. The intensity of the focused spot pair in the central portion in the sub-scanning direction is significantly higher than the maximum level of each focused spot SP.

On the other hand, when the array aperture plate 39 is used, the intensity distribution by the focused spot pair formed on the thermal sensitive material T by the laser beam L divided by the array refraction element 36 is shown in FIG. As shown in (B), the intensity distributions of the respective focused spots SP are combined in the sub-scanning direction, but the overlapping region of the focused spots SP is the laser beam that is the source of each focused spot. Since the predetermined areas at both ends of L in the sub-scanning direction are shielded by the array aperture plate 39, the intensity at the central portion of the focused spot pair in the sub-scanning direction is set to each focus spot SP.
Can be suppressed to about the maximum level, and as a result, the occurrence of ablation can be almost certainly prevented.

In this case, on the thermal sensitive material T, as an example, beam spots S1 'to S15' (FIG. 10 (B)) having the intensity distribution in the state shown in FIG. 12 (B) are formed.

The beam spots S1 'to S15' are
As shown in FIG. 10B, the exposure head 12 is fed in the sub-scanning direction at a feed interval W ′ and the drum 1
4 is rotated in the main scanning direction so that the resolution is K0.
A two-dimensional image of (dpi) is formed on the thermal sensitive material T (step 110).

As described above, the resolution of the recorded image is set to 2 · K0.
When (dpi) is changed to K0 (dpi), the beam spots S1 to S15 are changed to beam spots S1 ′ simply by inserting the array refracting element 36 in the optical path of the laser beam L.
To S15 ', the image can be recorded at high speed because the sub-scanning speed is increased.

Similarly, the resolution can be changed from K0 (dpi) to 2.K0 (dpi). The process of step 100 corresponds to the input means of the present invention.

In the fifth embodiment, the array aperture plate 39 is used as the laser beam L in the fiber array section 30.
Since the fiber array portion 30 is disposed in the vicinity of the emission port of the laser beam L, the fiber array portion 30 is heated by the laser beam L reflected from the non-opening portion of the array aperture plate 39, that is, the laser beam L shielded by the array aperture plate 39. It will be.

Therefore, the fiber array section 30 according to the present embodiment is preferably constructed as follows.
That is, as shown in FIG. 26A, V of the base 30A in the fiber array unit 30 of each optical fiber 20 is
A metal is vapor-deposited on the portion to be fitted into the groove, and FIG.
As shown in (B), the metal deposition portion is fixed to the base 30A with solder. As a result, the durability against heating can be improved as compared with the case where the optical fiber is fixed to the base 30A with a normal adhesive.

As described in detail above, in the laser recording apparatus 10E according to the fifth embodiment, the semiconductor laser LD
The laser beam L emitted from the laser beam L is focused on the thermal sensitive material T, and the laser beam L is moved in the sub-scanning direction by the array refracting element 36 disposed between the fiber array unit 30 and the thermal sensitive material T. Since the array aperture plate 39, which is divided into a plurality of portions and is arranged between the fiber array section 30 and the array refracting element 36, shields a predetermined region at the end portion in the sub-scanning direction of the laser beam L, the array refracting element 36. Since the area of the overlapping region becomes small when the light beams divided by are shifted in the center position on the thermal sensitive material T and a part of them are overlapped, the optical power in this region can be reduced. As a result, it is possible to prevent the occurrence of ablation.

Further, in the laser recording apparatus 10E according to the fifth embodiment, the predetermined area is collected from the center of the laser beam L on the thermal sensitive material T of the laser beam L divided by the array refracting element 36. Ablation occurs because the area outside the straight line in the main scanning direction is in contact with each of the two positions that are separated from each other on both ends in the sub scanning direction by a distance corresponding to a predetermined range including half the distance between the centers of the light spots. Can be almost certainly prevented.

Further, in the laser recording apparatus 10E according to the fifth embodiment, the array refracting element is provided between the fiber array section 30 and the thermal sensitive material T, and the laser beam is divided into a broad area of the laser beam. Since it is arranged so as to be parallel to the direction, the blur direction of the laser beam at the position deviated from the focus position of the laser beam to the front and rear of the optical axis direction (depth direction) is symmetrical with respect to the optical axis direction. As a result, the image quality of the recorded image can be improved, and the array refraction element can be constructed at a lower cost as compared with the case where a uniaxial crystal is used. As a result, the device can be manufactured at a low cost. Can be composed of

Further, in the laser recording apparatus 10E according to the fifth embodiment, since the array refraction element is arranged at the position where the far field pattern of the laser beam can be formed, the laser beam L emitted from each semiconductor laser LD.
The array refractive element can be similarly operated for all of the above.

Further, in the laser recording apparatus 10E according to the fifth embodiment, resolution information indicating the resolution of the image formed on the thermal sensitive material T by scanning exposure (corresponding to "resolution data" in the fifth embodiment). .) And the resolution indicated by the resolution information is the predetermined first resolution (2.K0 (dpi) in the fifth embodiment), the array refraction element is emitted from the semiconductor laser LD. When the resolution indicated by the resolution information is a second resolution lower than the first resolution (K0 (dpi) in each of the above embodiments), the array refracting element is retracted from the optical axis of the laser beam. Since the array refraction element is moved so as to be positioned above, the resolution at the time of recording an image on the thermal sensitive material T can be easily achieved by only inputting the resolution information. It is possible to further.

Further, in the laser recording devices 10A to 10E according to each of the above-mentioned embodiments, a plurality of semiconductor lasers LD are arranged along the dividing direction of the laser beam L by the array refracting element or the polarization separating element, and emitted from each semiconductor laser LD. Since the laser beams L thus generated are each divided by the array refracting element or the polarization separating element and guided to the thermal sensitive material T, an image can be recorded at high speed.

In the fifth embodiment described above, the case where the array refracting element 36 is arranged at a portion where the laser beam becomes substantially parallel light has been described, but the present invention is not limited to this, and for example, The part where the laser beam is focused,
That is, it may be arranged between the condenser lens 38 and the thermal sensitive material T, or a portion where the laser beam diverges, that is, between the fiber array section 30 and the collimator lens 32. it can. Also in this case,
The same effect as that of the fifth embodiment can be obtained.

Further, in each of the above embodiments, the case where the array aperture plate 39 is fixedly arranged on the optical path of the laser beam L has been described, but the present invention is not limited to this, and the element moving motor 40. Array refraction element 36 by
Alternatively, the array aperture plate 39 may be inserted into or removed from the optical path in conjunction with the insertion / extraction of the laser beam L of the polarization separation element into or out of the optical path. Also in this case, the same effect as that of each of the above-described embodiments can be obtained.

Further, in each of the above-mentioned embodiments, the present invention is applied to laser recording devices 10A to 10E for performing multi-beam scanning.
However, the present invention is not limited to this, and the present invention can be applied to, for example, a laser recording device for performing a single beam scan in which a light source is composed of one semiconductor laser. Also in this case, the same effect as that of each of the above-described embodiments can be obtained.

[0214]

As described in detail above, according to the exposure apparatus of the first aspect, at least in the sub-scanning direction, the light beam emitted from the light source for emitting the light beam emitted in the broad area is The first optical system once condenses between the light source and the recording medium, condenses the condensed light beam on the recording medium, and at the same time, the condensing position of the light beam by the first optical system and the recording medium. The light beam is divided into a plurality of light beams in the sub-scanning direction by the light splitting device disposed between the light beams, and the light beam scanning device is disposed at the light beam focusing position by the first optical system. Since the predetermined area is shielded from light, the area of the overlapping area becomes small when the light beams split by the light splitting means are shifted in their center positions on the recording medium and a part of them are overlapped. Light power Can fence, it is possible to prevent the occurrence of ablation as a result, the effect is obtained that.

According to the exposure apparatus of the second aspect, at least in the sub-scanning direction, the light beam emitted from the light source that emits the light beam emitted in the broad area is condensed on the recording medium, and A light splitting means arranged between the light beam emission port and the recording medium divides the light beam into a plurality of parts in the sub-scanning direction, and a light blocking means disposed between the emission port and the light splitting device. Since a predetermined area at the end of the light beam in the sub-scanning direction is shielded by the light beam, the light beam split by the light splitting means is shifted from the center position on the recording medium to partially overlap the light beam. Since the area is reduced, the optical power in this region can be reduced, and as a result, the occurrence of ablation can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram (plan view) of a laser recording device 10A according to a first embodiment.

FIG. 2 is a schematic configuration diagram (side view) of a fiber array unit 30 according to an embodiment.

FIG. 3 is an array refraction element 36 according to the first and fifth embodiments.
2 is a schematic configuration diagram (plan view) showing the configuration of FIG.

FIG. 4 is a diagram showing a state of a focused spot in the laser recording device according to the embodiment, and FIG. 4A is a thermal sensitive material when the array refracting element or the polarization separating element is not positioned on the optical path of the laser beam L. (B) shows the state of the focused spot formed on the thermal sensitive material T when the array refracting element or the polarization splitting element is positioned on the optical path of the laser beam L. FIG. 3 is a schematic diagram showing each.

FIG. 5 is a schematic configuration diagram showing a configuration of an array aperture plate 39 according to the embodiment.

FIG. 6 is a schematic configuration diagram showing a configuration of an opening 39A provided in the array opening plate 39 according to the embodiment.

FIG. 7 is a schematic diagram for explaining a light shielding unit of the present invention and a region shielded by an array aperture plate 39 according to the embodiment.

FIG. 8 is a block diagram showing a configuration of a control system of the laser recording apparatus according to the embodiment.

FIG. 9 is a flowchart showing the flow of processing when image recording is performed according to resolution in the laser recording devices according to the first, second, and fifth embodiments.

FIG. 10 is a schematic view showing a state of a beam spot on the thermal sensitive material T by the laser recording device according to the embodiment.

FIG. 11 is a schematic diagram (plan view) for explaining the operation of the laser recording apparatus 10A according to the first embodiment.

12A and 12B are diagrams for explaining the effect of the laser recording apparatus according to the embodiment, and FIG. 12A is an intensity of a focused spot pair formed on the thermal sensitive material T when the array aperture plate 39 is not used. FIG. 6B is a schematic diagram showing the distribution, and FIG. 6B is a schematic diagram showing the intensity distribution by the focused spot pairs formed on the thermal sensitive material T when the array aperture plate 39 is used.

FIG. 13 is a schematic configuration diagram (plan view) showing another configuration example of the array refraction element of the present invention.

FIG. 14 is a graph showing a state example of the intensity distribution of the laser beam L according to the embodiment.

FIG. 15 is a schematic configuration diagram (plan view) of a laser recording device 10B according to a second embodiment.

FIG. 16A is a schematic diagram (plan view) for explaining the operation of the laser recording apparatus 10B according to the second embodiment,
(B) is a schematic diagram (plan view) for explaining the configuration and action of the array refraction element 36 ′ according to the second embodiment.

FIG. 17 is a schematic configuration diagram (plan view) of a laser recording device 10C according to a third embodiment.

FIG. 18 is a schematic diagram (plan view) for explaining the configuration and action of the polarization beam splitting element 37 according to the third embodiment.

19A is a schematic configuration diagram (a front view and a side view) of a polarization direction control element 34 according to the third and fourth embodiments, and FIG. 19B is a crystal optical axis of the polarization direction control element 34. It is the schematic which shows a direction.

FIG. 20 is a schematic diagram showing a laser beam separation state by a polarization separation element 37 when the polarization direction control element is not used in the laser recording devices according to the third and fourth embodiments.

FIG. 21 is a schematic diagram showing a laser beam separation state by a polarization separation element 37 when a polarization direction control element 34 is used in the laser recording devices according to the third and fourth embodiments.

FIG. 22 is a flowchart showing the flow of processing when image recording is performed according to resolution in the laser recording devices according to the third and fourth embodiments.

FIG. 23 is a schematic configuration diagram (plan view) of a laser recording device 10D according to a fourth embodiment.

FIG. 24 is a schematic diagram (plan view) for explaining the operation of the polarization beam splitting element 37 ′ according to the fourth embodiment.

FIG. 25 is a schematic configuration diagram (plan view) of a laser recording device 10E according to a fifth embodiment.

FIG. 26 is a schematic view showing a more preferable configuration of the fiber array section 30 used in the laser recording apparatus 10E according to the fifth embodiment.

FIG. 27 is a schematic diagram for explaining the principle of the conventional technique.

[Explanation of symbols]

10A, 10B, 10C, 10D, 10E Laser recording device 32 Collimator lens (optical system) 32A First collimator lens (first optical system) 32B Second collimator lens (second optical system) 34 Polarization direction control element (light splitting means) ) 36 array refracting element (light splitting means) 36 'array refracting element (light splitting means) 37 polarization separating element (light splitting means) 37' polarization separating element (light splitting means) 38 condensing lens (optical system) 38A 1st Condensing lens (first optical system) 38B Second condensing lens (second optical system) 39 Array aperture plate (light shielding means) 40 Element moving motor (moving means) L Laser beam (light beam) LD Semiconductor laser (light source) T Thermal sensitive material (recording medium)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/027 H01L 21/30 529 5C074 H04N 1/113 B41J 3/00 D 5F046 1/23 103 H04N 1 / 04 104Z F term (reference) 2C362 AA09 AA29 AA34 AA40 BA25 BA26 BA29 BA58 BA60 BA85 BA86 BA90 CB71 DA03 2H045 AG09 BA22 BA26 BA33 CB24 CB33 DA24 2H097 AA03 AA16 BA01 BB01 BB10 CA03 CA17 2H072 CA16 2A0BAABA BA17 BAH HA10 5C074 AA02 BB17 DD06 DD14 EE02 EE04 GG12 5F046 BA07 CA03 CB04 CB05 CB14 CB27

Claims (5)

[Claims] 1. An exposure apparatus for forming an image on a recording medium by scanning exposure, comprising: a light source for emitting a light beam emitted in a broad area at least in the sub-scanning direction; and the light beam emitted from the light source. A first optical system for condensing the light beam between the light source and the recording medium, a second optical system for condensing the light beam condensed by the first optical system on the recording medium, A light splitting unit that is disposed between the condensing position of the light beam by one optical system and the recording medium and splits the light beam into a plurality in the sub-scanning direction; and the light by the first optical system. An exposure apparatus comprising: a light shielding unit which is disposed at a beam condensing position and shields a predetermined region at an end of the light beam in the sub-scanning direction. 2. An exposure device for forming an image on a recording medium by scanning exposure, comprising a light source for emitting a light beam emitted in a broad area at least in the sub-scanning direction, and the light beam emitted from the light source. Is disposed between the recording medium and an optical system for condensing the light beam on the recording medium, and the light beam is divided into a plurality in the sub-scanning direction. An exposure apparatus comprising: a light splitting unit; and a light blocking unit that is disposed between the emission port and the light splitting unit and that blocks a predetermined region at an end of the light beam in the sub-scanning direction. 3. The predetermined area is within a predetermined range of distance from the center of the light beam to a half of the center-to-center distance of the focused spot on the recording medium of the light beam split by the light splitting means. 3. The exposure apparatus according to claim 1, wherein the area is located outside the straight line in the main scanning direction, which is in contact with each of the two positions separated by the corresponding distance on both ends in the sub scanning direction. 4. The light splitting means is configured such that refracting members having a unit surface shape for splitting one light beam into two are arranged in pairs in a pair unit, and the splitting direction of the light beam is An array refraction element arranged so as to be substantially parallel to the broad area direction of the light beam emitted from the light source, or a polarization separation element for separating the light beam into two lights whose polarization directions are orthogonal to each other And the crystal optical axis is 45 with respect to the polarization direction of the light beam that is arranged between the light source and the polarization separation element and is separated by the polarization separation element.
4. The exposure apparatus according to claim 1, further comprising: a polarization direction control element configured by arranging a half-wave plate so as to be tilted at an angle in a predetermined range including a degree. . 5. An input device for inputting resolution information indicating a resolution of an image formed on the recording medium by scanning exposure, and the resolution when the resolution indicated by the resolution information is a predetermined first resolution. The light splitting means is retracted from the optical axis of the light beam, and the light splitting means is positioned on the optical axis when the resolution indicated by the resolution information is a second resolution lower than the first resolution. The exposure apparatus according to any one of claims 1 to 4, further comprising: a moving unit that moves the light splitting unit.