JPH0279812A - Multiplex light source unit and scanning device - Google Patents

Abstract

PURPOSE:To miniaturize the title device and to improve the reliability of the device by projecting a laser beam and a beam group from a housing in respectively difference directions. CONSTITUTION:Ten semiconductor lasers 3A to 3J whose laser projection axes are parallel with each other are fixed on the upper plate 2A of a supporting body 2 in a multiplex light source unit 1. Since a prism mirror corresponding to a laser beam 3i projected from a semiconductor laser 3I is disposed on a position vertically separated from other prism mirrors 5, laser beam groups 3a to 3g, 3j are projected from the housing in a direction different from the projecting direction of the laser beam 3i. Consequently, a scanning system and a synchronizing system are set up to a state similar to the sharing state of a light source in addition to the sharing of a mechanical deflector such as the rotary polygon mirror, so that the device can be miniaturized and the reliability of the device can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a scanning device used for reading, recording, etc. of images, and a multiplexing light source unit having a large number of semiconductor lasers used in the scanning device. .

(Prior art) A light beam containing image information (for example, The image information reading device that reads the image information recorded on the sheet by detecting the reflected light, transmitted light, and emitted light using a photodetection means equipped with a photomultiplier tube, etc., is used as a prepress scanner, computer, and facsimile input device. It has been widely used in practical applications as devices and the like.

Also, when irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), some of this radiation energy is accumulated in the phosphor, and when it is subsequently irradiated with excitation light such as visible light, Using a stimulable phosphor (stimulable phosphor) that exhibits stimulated luminescence in response to accumulated energy, radiation image information of a subject such as a human body is recorded on a -H sheet-shaped stimulable phosphor, This stimulable phosphor sheet is scanned with excitation light such as a laser beam to generate stimulated luminescence light, the resulting stimulated luminescence light is read photoelectrically to obtain an image signal, and based on this image signal, the image of the subject is detected. Radiographic images are recorded on recording materials such as photographic materials, CRTs, etc.
The present applicant has already proposed a radiographic image information recording and reproducing system that outputs a visible image on a computer, etc.
No. 183472, No. 5Ei-104645.

No. 55-116340 etc. ).

In the above system, the image information accumulated and recorded on the stimulable phosphor sheet is transmitted to the radiation image information reader by deflecting excitation light to main scan the stimulable phosphor sheet and connecting the stimulable phosphor sheet with the excitation light. The whole surface of the stimulable phosphor sheet is scanned with excitation light by relatively moving in the sub-scanning direction, and the stimulated luminescence light emitted from the scanning position is read by photoelectrically detecting it with a photodetector.

On the other hand, the image information read by each of the image information reading devices described above is transferred onto a recording sheet relatively transported in the sub-scanning direction by an image recording device based on the image signal obtained by the reading device. By main-scanning the modulated light beam, it is reproduced and recorded as a visible image.

The image reading device, image recording device, and the like often use a scanning device that causes a light beam to perform main scanning. It is conventionally known to use a semiconductor laser as a light source for a scanning beam of the scanning device.

Semiconductor lasers have the advantages of being smaller, cheaper, and consume less power than gas lasers. In addition, semiconductor lasers are capable of so-called analog direct modulation, in which the output is changed by controlling the drive current, so they can be used as optical light modulators ( A
There is no need to separately provide an optical modulator such as OM), and there are no problems such as moving the AOM in and out of the optical path depending on the presence or absence of modulation.

However, although semiconductor lasers have the above-mentioned advantages, their current output is only 20 to 30 mW when continuously oscillated, and therefore image information reading requires high-energy scanning light as excitation light. It is difficult to use it as a light source for reading light in devices and the like.

Therefore, as mentioned above, in order to obtain a sufficiently high-energy scanning beam from a semiconductor laser with low optical output, it is necessary to use multiple semiconductor lasers and combine the laser beams emitted from these semiconductor lasers into one beam. is possible.

In order to combine the laser beams emitted from multiple semiconductor lasers into one laser beam as described above and use it as a scanning beam, the laser beams emitted from each semiconductor laser are usually collimated by a collimator lens. After the light is converted into light, it is common to guide the light into parallel optical paths that are close to each other and to make the light enter an optical deflector.

In addition, the above-mentioned scanning device usually requires not only a light source and an optical system that simply scan the sheet, but also a scanning beam that is used to detect the main scanning position on the sheet when the scanning beam scans the sheet. A means for generating a signal synchronized with main scanning by a synchronous beam, that is, a synchronous beam light source, a synchronous beam detector for detecting the synchronous beam, and a synchronous optical system for guiding the synchronous beam from the synchronous beam light source to the synchronous beam detector. It is equipped with Since the purpose of the synchronization beam is simply to generate a synchronization signal, unlike the above-mentioned scanning beam, it is a light beam with a small amount of light that can be detected by a synchronization beam detector.
For example, a laser beam emitted from one semiconductor laser is sufficient.

Therefore, a multiplexing light source unit that uses a large number of semiconductor lasers to combine laser beams emitted from the large number of semiconductor lasers and outputs a scanning beam, and a synchronous beam composed of - semiconductor lasers, for example. A scanning system (combined light source unit and scanning beam that guides the scanning beam emitted from the unit onto the sheet) can be used with It is conceivable that the synchronization system (consisting of an optical system) and the synchronization system (consisting of a synchronization beam light source, a synchronization optical system, and a synchronization beam detector) are provided as separate systems from each other.

(Problem to be Solved by the Invention) However, if the scanning system and the synchronization system share a rotating polygon mirror, etc. as described above, the number of parts of the scanning device increases, and this becomes an obstacle when downsizing the scanning device. Furthermore, it is very difficult to adjust each component to obtain a synchronization signal that accurately monitors the main scanning position on the sheet, and even after adjustment, there is a problem that warping is likely to occur in the front shaft and the like.

The present invention has been made in view of the above problems, and
It is an object of the present invention to provide a scanning device that allows easy adjustment of a scanning system and a synchronization system and is suitable for downsizing, and a multiplexed light source unit for this scanning device.

(Means for Solving the Problems) A multiplexed light source unit of the present invention includes a housing, a number of semiconductor lasers arranged in the housing, and a plurality of semiconductor lasers arranged on the optical path of each laser beam emitted from these semiconductor lasers. A number of collimator optical systems convert each of the laser beams into a bundle of parallel rays; A combining optical system that forms a beam group having an optical axis in a different direction from the optical axis of the beam, and the one laser beam and the beam group are emitted from the housing in mutually different directions. It is something to do.

Here, forming a large number of laser beams into a group of beams having parallel optical axes close to each other (hereinafter referred to as "combining") means that the laser beams are incident on the same reflecting surface of an optical deflector and are deflected. This means that the laser beams are emitted in a state where they can be collectively treated as one beam, such as being able to be focused at the same position by one scanning lens.

Further, in that case, some of the laser beams may be emitted so as to have exactly the same optical path.

Further, the scanning device of the present invention main scans a recording sheet in a predetermined direction with a laser beam, and sub-scans the recording sheet and the laser beam relatively in a direction substantially perpendicular to the main scanning direction. In the scanning device, the above-described combined light source unit, a mechanical deflector that simultaneously deflects both the one laser beam and the beam group emitted from the combined light source unit, and a scanning optical system provided so that the beam group scans the recording sheet while maintaining a predetermined beam diameter; The present invention is characterized by comprising a synchronous photodetector that outputs a signal synchronized with the main scanning on the recording sheet.

Here, when this scanning device is used as a reading device, the recording sheet refers to a photosensitive film on which an image has already been recorded, a stimulable phosphor sheet on which the radiation image information described above is accumulated, and the like. When the device is used as a recording device, it refers to a photosensitive film etc. before recording.

(Function) Since the multiplexing light source unit of the present invention accommodates a large number of semiconductor lasers and accompanying optical elements in one housing, these semiconductor lasers and optical elements in the housing can
Furthermore, there is little variation in temperature between these semiconductor lasers and each optical element, and there is little deviation after optical adjustment. Further, since the multiplexing light source unit of the present invention is configured such that both the laser beam group and one laser beam are emitted from one housing, the laser beam group and one laser beam By arranging the two units to be ejected from separate units, it is possible to reduce the size of the unit as a whole. Furthermore, if the beam group and one laser beam are emitted from the housing so that they have parallel optical axes, in a scanning device etc. that uses these beams for scanning, the beam group and one laser beam Although a somewhat complicated optical system is required to separate and scan simultaneously, in the scanning device of the present invention, the laser beam group and one laser beam are emitted from the housing in mutually different directions. A group of laser beams and a single laser beam can be easily separated outside the housing.

Since the scanning device of the present invention uses the above-mentioned multiplexing light source unit, the scanning system and the synchronization system are almost the same as sharing not only a mechanical deflector such as a rotating polygon mirror but also a light source. It is possible to achieve smaller size and higher reliability.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of a multiplexing light source unit of the present invention.

In the illustrated multiplexing light source unit 1, the upper plate 2 of the support body 2
A has ten semiconductor lasers 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3 whose laser emission axes are parallel to each other.
H, 3I, and 3J are fixed, and 10
Concave lenses 4 are mounted on the lower plate 2C, and 1 is an optical path adjustment element.
0 prism mirrors 5 are arranged in between. Note that the semiconductor lasers 3A to 3J, the concave lens 4, and the prism mirror 5 are connected to the upper plate 2A and the middle plate 2B, respectively.
, are arranged symmetrically with respect to the wall portion 2D of the support body that integrally supports the lower plate 2C.

A convex lens 6 is disposed inside the upper plate 2A, facing each of the semiconductor lasers 3A to 3J.

(As an example, the convex lens 6 facing the semiconductor laser 3A is shown in FIG. 2, which is a sectional view taken along the line X--X in FIG. 1). In this device, the concave lens 4 and the convex lens 6 constitute a collimator optical system. As shown in FIG. 2, the laser beam 3a emitted from the semiconductor laser 3A becomes a parallel beam by passing through this collimator optical system, and the laser beams 3b to 3j emitted from the other semiconductor lasers 3B to 3J also become parallel beams. A collimator optical system placed on each optical path converts the beam into a parallel beam.

Laser beam 3a, which has become a parallel beam, BCs'd
After being reflected by the prism mirror 5 disposed below, esag and at enter the polarized beam splitter. The semiconductor lasers 3A and 3C.

3E, 3G, 3I are laser beams 3as 38% 31
3.3g531 are arranged in the same plane by injection, and each prism mirror 5 on the optical path of these laser beams is as shown in the figure, except for the prism mirror 5a corresponding to the laser beam 31. Since the laser beams 3a and 3c are arranged to be gradually shifted in the vertical direction, the laser beams 3a and 3c
The reflection position of s 3es 3g by the prism mirror 5 is slightly shifted only in the vertical direction, and the laser beams 3a, BcsBe, 3g reflected by each prism mirror 5 are
take parallel optical paths very close to each other in the vertical direction. Further, on the back side of the wall portion 2D, a semiconductor laser 3B
, 3D, 3F, 3H, 3J, the laser beams ab, ad, sr, ah, aj are exactly the same,
The light beams are reflected by the prism mirror 5 and take parallel optical paths very close to each other in the vertical direction. In addition, except for the laser beam 8j, laser beams 3a to 3h (for example, laser beams 3a and 3b) emitted from semiconductor lasers placed at opposing positions across the wall 2D are included.

The heights of the laser beams 3c and ad) reflected by the prism mirror 5 are equal to each other, and the polarization directions of the laser beams 3a to 3g reflected by the prism mirror 5 of these semiconductor lasers 3A to 3G are equal to each other. It is fixed to the upper plate 2a so as to be uniform (in the direction of arrow a in FIG. 1).

Also, the laser beam 3 emitted from the semiconductor laser 3J
j is also reflected by the corresponding prism mirror 5, and takes a parallel optical path close to each other in the vertical direction with the laser beams 3b, 3d, 3r, and 3h.

However, the laser beam 3j emitted from the semiconductor laser 3I has a corresponding prism mirror 5a located vertically apart from other prism mirrors as shown in the figure, and the inclination of the mirror surface is different from that of the other prism mirrors. are different.

The polarizing beam splitter 7 has a characteristic of reflecting light polarized in the direction of arrow a, and the polarizing beam splitter 7
a, 3c, 3e, 3g, and 31 are reflected by this polarizing beam splitter. On the other hand, laser beam 3b
, 3d, 34.3h, and 3j are reflected by the mirror 8 to change the optical path by about 90 degrees, and then pass through the 1/2 wavelength plate 9 to change the polarization direction by 90 degrees, and are polarized in the direction indicated by the arrow. Becomes light. The polarizing beam splitter 7 transmits light polarized in the direction indicated by the arrow, and therefore the laser beams 3b, 3d,
8f', 3h, and 3j pass through the polarizing beam splitter 7, and the laser beam 3b becomes the laser beam 3a, the laser beam 3d becomes the laser beam 3C, the laser beam 3' becomes the laser beam 3e, and the laser beam 3h becomes the laser beam. The laser beams 3g and 3g are respectively emitted onto the same optical path.The laser beam 3j is also emitted so as to have an optical path close to and parallel to these optical paths.In this way, the nine laser beams are emitted close to each other and onto parallel optical paths. Laser beams 3a to 3g, 3
The beam cross section of j is shown in FIG.

As described above, the laser beam 31 is reflected by the prism mirror 5a in a direction different from that of the other laser beams 3a to 3g, 3j, and then further reflected by the beam splitter 7. Therefore, the laser beam 31 is transmitted from the multiplexed light source unit 1 to the other multiplexed laser beams 3a to 3a.
It is ejected in a different direction from 3g and 3j.

Further, this multiplexing light source unit 1 includes laser beams 3a to 3a.
The entire body is covered with a housing (not shown) having an opening through which 3j is injected.

In this way, a group of laser beams (
Since the laser beams 3a to 3g are configured so that both 3D and one laser beam 31 are emitted,
Compared to emitting two laser beams (or beam groups) from separate units, the overall unit can be made more compact, and the long-term deviation of the optical axis of the two laser beams (or beam groups) can be avoided. Hard to occur. Further, since the laser beam group (laser beams 3a to 3g, 3D and one laser beam 31) are emitted from the housing in mutually different directions, they can be easily separated after being emitted from the housing.

FIG. 4 is a perspective view showing an example of an image reading and recording device using an embodiment of the scanning device of the present invention.

First, a case where this image reading/recording device is used as an image reading device will be described.

The combined laser beams 3a to 3g, 3j emitted from the combined light source unit 1 described above are used as a scanning beam 11, and the laser beam 31 emitted in a direction different from the laser beams 3a to 3g, 3j is a synchronous beam. It is used as 12.

After the scanning beam 11 (laser beams 3a to 3g, 3D passes through the cylindrical lens 13, the synchronous beam 12
(Laser beam 31) does not enter the cylindrical lens 13, but passes below the cylindrical lens 13, and then is reflected and deflected by the rotating polygon mirror 14. The rotating polygon mirror 14 is rotated at high speed in the direction of arrow A shown in the figure by a motor (not shown). The scanning beam reflected and deflected by the rotating polygon mirror 14 passes through the fθ lens 15 and is further reflected by the cylindrical mirror 16, whereupon a radiographic image is accumulated and recorded and conveyed by sheet conveyance means (sub-scanning means) such as an endless belt 17. The stimulable phosphor sheet 18 that is conveyed (sub-scanned) in the direction of arrow Y is repeatedly scanned in the main-scanning direction (direction of arrow X shown in the figure) substantially perpendicular to the sub-scanning direction. That is, two-dimensional scanning is performed by the scanning beam 11 over the entire surface of the stimulable phosphor sheet 18 by the main scanning and sub-scanning. During this scanning, the cylindrical lens 13, fθ lens 15, and cylindrical mirror 16 are installed so that the spot diameter of the scanning beam on the stimulable phosphor sheet 18 is always the same regardless of the rotation of the rotating polygon mirror 14. It is configured.

Stimulable phosphor sheet 1 scanned by scanning beam 11
8 emits stimulated light in accordance with the image information accumulated and recorded at each scanning point, and this emitted light is transmitted to a transparent glass plate having an incident end face 19a parallel to the main scanning line in the vicinity of the stimulable phosphor sheet 18. The light enters the light guide 19 from the incident end surface 19a. The light guide 19 has an incident end surface 19a formed in a planar shape, gradually becoming cylindrical toward the rear end, and a rear end 19b that is approximately cylindrical and provided on the exit end surface. It is coupled to a photomultiplier 20. The stimulated luminescent light entering from the incident end surface 19a is guided to the rear end portion 19b, and is transmitted to the photomultiplier 20 via an optical filter (not shown) that selectively transmits the stimulated luminescent light.

The stimulated luminescent light is converted into an electrical signal (analog image signal) Ss in the photomultiplier 20.

On the other hand, the synchronous beam 12 reflected and deflected by the rotating polygon mirror 14
After passing through the fθ lens 15, the synchronous beam detector 2
1, the light receiving surface is scanned, and a pulse train-shaped synchronization signal S3 synchronized with the scanning is transmitted to the synchronization beam detector 21.
is output from. By counting the number of pulses of the synchronizing signal S2, it is possible to know which position on the stimulable phosphor sheet 18 the scanning beam 11 is currently main-scanning.

The analog image signal S1 output from the photomultiplier 20 is logarithmically amplified by the logarithmic amplifier 22 and then input to the A/D converter 23. Also, the A/D converter 2
3, a synchronizing signal S2 is also input, and the analog image signal S1 is sampled at time intervals synchronized with the synchronizing signal S2 and A/D converted to obtain a digital image signal S3. This image signal S3 is sent to the image processing device and subjected to appropriate image processing, and the image signal 83' after the image processing is sent to the image recording device, where a visible image based on the image signal 83' is reproduced and recorded. .

Next, a case where the image reading/recording apparatus shown in FIG. 4 is used as an image recording apparatus for reproducing and recording images will be described. Duplicate explanations of points common to the case of image reading will be omitted.

When reproducing and recording images, the image signal 83 after image processing
' and the synchronization signal S2 are input to the semiconductor laser drive circuit 24, which drives the scanning beam 11 (laser beams 3a to 3g,
3j) is intensity-modulated in synchronization with the synchronizing signal S2, and the semiconductor lasers 3A to 3G and 3J (see FIG. 1) are driven so that an image based on the image signal 83' is reproduced and recorded on the photosensitive film 25.

The intensity-modulated scanning beam 11 emitted from the multiplexing light source unit 1 is directed to a photosensitive film 2 that is conveyed in the direction of arrow Y.
5 by main scanning in the X direction, the photosensitive film 25
Play and record the image on top. In FIG. 4, the stimulable phosphor sheet 18 and the photosensitive film 25 are depicted as pointing to the same sheet, but when reading, the stimulable phosphor sheet 8 is shown, and when recording, the photosensitive film 25.

In this way, the scanning device shown in FIG. 4 uses the multiplexed light source unit shown in FIG. Since one laser beam 31 is used as a synchronous beam, the scanning beam and synchronous beam light sources can be treated as one light source as a multiplexed light source unit, so to speak.

By sharing the optical system, it is possible to downsize the device, and it is also possible to realize a highly reliable device that is less likely to lose synchronization over a long period of time.

In the above embodiments, a system using a stimulable phosphor sheet has been described, but the light beam scanning device of the present invention is not limited to a system using a stimulable phosphor sheet, and can be used to record images. Needless to say, the present invention can also be implemented in systems that obtain image signals by scanning X-ray film. Furthermore, the present invention can be widely applied not only to systems that handle radiographic images as in the above embodiments, but also to systems that handle general images.

Furthermore, in the above embodiments, an image reading/recording device capable of both reading and reproducing/recording images has been described. These are applied independently to each image recording device.

(Effects of the Invention) The multiplexing light source unit of the present invention includes a large number of semiconductor lasers and optical systems attached to them in a housing, and a single laser beam and a beam group obtained by combining a large number of laser beams into a housing. Since the light beams are configured to emit in different directions from each other, it is possible to realize a highly reliable unit that is unlikely to cause long-term misalignment of the optical axis, and the unit can also be made smaller. Further, the beam group and one laser beam can be easily separated from each other outside the housing.

Furthermore, since the scanning device of the present invention uses the above-mentioned multiplexing light source unit, the entire optical system can be constructed so that both the scanning beam and the synchronizing beam light sources are shared, so that the device can be made more compact. High reliability can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the multiplexed light source unit of the present invention, FIG. 2 is a sectional view taken along the line XX in FIG. 1, and FIG. 3 is the multiplexed light source shown in FIG. 1. A schematic view showing a cross section of a laser beam emitted from a unit. FIG. 4 is a perspective view showing an example of an image reading/recording device using an embodiment of the scanning device of the present invention. 1... Combined light source unit 2... Support bodies 3A-3
J... Semiconductor lasers 3a to 3j... Laser beam 4... Concave lens 5
．． 5a... Prism mirror 6... Convex lens 7...
・Polarizing beam splitter 8...Mirror 9...1/2 wavelength range 1
1...Scanning beam 12...Synchronized beam 1
3... Cylindrical lens 14... Rotating polygon mirror 15... fθ lens 16... Cylindrical mirror 18... Stimulative phosphor sheet 19... Light guide 20
... Photomultiplier 21 ... Synchronous beam detector

Claims (2)

[Claims] (1) A housing, a number of semiconductor lasers arranged within the housing, and a number of collimators provided on the optical path of each laser beam emitted from these semiconductor lasers to convert each laser beam into a bundle of parallel rays. An optical system and a number of laser beams other than one of the laser beams are formed into a beam group that is close to each other and has an optical axis in a direction different from the optical axis of the one laser beam. A multiplexing light source unit comprising: a multiplexing optical system, wherein the one laser beam and the beam group are emitted from the housing in mutually different directions. (2) A scanning device that main scans a recording sheet in a predetermined direction with a laser beam and sub-scans the recording sheet and the laser beam relatively in a direction substantially perpendicular to the main scanning direction, as claimed in claim 1. The multiplexing light source unit according to 1, a mechanical deflector that simultaneously deflects both the one laser beam and the beam group emitted from the multiplexing light source unit, and the beam deflected by the deflector. A scanning optical system is provided so that the group scans the recording sheet while maintaining a predetermined beam diameter, and the one laser beam deflected by the deflector is incident and the recording by the beam group is performed. A scanning device comprising a synchronous photodetector that outputs a signal synchronized with main scanning on a sheet.