JP2002077525A - Radiation image information reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a device and to uniformize the intensity distribution of linear stimulating light in a radiation image information reader for irradiating a stimulable phosphor sheet where radiation image information is stored and recorded with the linear stimulating light emitted from a laser diode and detecting stimulated light diverged from the irradiation part in a line sensor. SOLUTION: This radiation image information reader is provided with the plural laser diodes 11a, 11b and 11c, etc., for irradiating a part of the stimulable phosphor sheet where the radiation image information is stored with the stimulating light 10a, 10b and 10c, etc., and a cylindrical lens 12 for condensing the exciting light 10a, 10b and 10c, etc., in one direction and linearly converging it as stimulating light irradiation means. The laser diodes 11a, 11b and 11c, etc., are disposed so as to range the respectively emitted stimulating light 10a, 10b and 10c, etc., in the length direction of a stimulating light irradiation part with each other in a direction where a beam spread direction vertical to a joined surface almost matches with the ranging direction of the stimulating light 10a, 10b and 10c, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of irradiating a stimulable phosphor sheet on which radiation image information is stored with excitation light, and photoelectrically reading stimulated emission light emitted from the sheet. The present invention relates to a radiation image information reading apparatus that obtains an image signal indicating a radiation image, and more particularly, to a radiation image information reading apparatus that irradiates a stimulable phosphor sheet linearly with excitation light and detects stimulated emission light with a line sensor. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, when a radiation is irradiated, a part of the radiation energy is accumulated, and then, when an excitation light such as a visible light or a laser light is irradiated, a storage light which shows a stimulated emission according to the accumulated radiation energy. Phosphor (stimulable phosphor)
A radiation image recording / reproducing system using a stimulable phosphor sheet obtained by laminating the stimulable phosphor on a support is widely used.

This radiation image recording / reproducing system irradiates the stimulable phosphor sheet with radiation transmitted through a subject such as a human body, and accumulates and records radiation image information of the subject on the stimulable phosphor sheet. The sheet is two-dimensionally scanned with excitation light such as laser light to generate stimulated emission light from the excitation light irradiated portion, and the stimulated emission light is read by photoelectric reading means to indicate the radiation image information. An image signal is obtained (for example, see JP-A-55-12429,
55-116340, 56-104645, etc.).

An image signal obtained by this system is subjected to image processing such as gradation processing and frequency processing suitable for observation and interpretation, and a radiation image carried by the signal is converted into a visible image for diagnosis on a film. Playback recording or CR
It is used for displaying on a T image display device or the like. In addition,
When the stimulable phosphor sheet after reading the radiation image information is irradiated with erasing light and the remaining energy is released, the sheet is in a state in which the radiation image information can be again stored and recorded, and the sheet can be used repeatedly. Will be possible.

Further, in order to enhance the detection quantum efficiency in radiation image formation, that is, the radiation absorptivity, the photostimulated luminous efficiency, and the extraction efficiency of the photostimulated luminescent light, the radiation absorbing function and energy storage of the conventional stimulable phosphor sheet are improved. A new type of stimulable phosphor sheet which is separated from the function has also been proposed (Japanese Patent Application No. 11-372978).

The stimulable phosphor sheet is capable of absorbing light in the ultraviolet to visible region and storing its energy, and emits the energy as stimulated emission when excited by light in the visible to infrared region. It contains a stimulable phosphor layer dedicated to storage.

[0007] This new type of stimulable phosphor sheet preferably has a form in which a radiation absorbing phosphor layer containing a phosphor that absorbs radiation and emits light in the ultraviolet to visible region is added. In that case, the energy of light in the ultraviolet to visible region (which corresponds to the radiation image information) emitted from the radiation absorbing phosphor layer when the radiation having the image information is irradiated is stimulated by the radiation. Is accumulated in the layer of the luminescent phosphor. Then, if the stimulable phosphor sheet is thereafter scanned with excitation light, stimulable luminescent light indicating radiation image information is emitted from the stimulable phosphor layer.

[0008] This new type of stimulable phosphor sheet may also be formed without the radiation absorbing phosphor layer described above. In this case, the stimulable phosphor sheet is used in combination with a phosphor screen having a radiation-absorbing phosphor layer containing a phosphor that absorbs radiation and emits light in the ultraviolet to visible region.

That is, when the phosphor screen is irradiated with radiation while the phosphor screen is in close contact with the stimulable phosphor sheet, the light in the ultraviolet to visible region emitted from the radiation absorbing phosphor layer of the phosphor screen is emitted. Energy (which corresponds to the radiation image information) is stored in the stimulable phosphor layer of the stimulable phosphor sheet. Therefore, also in this case, if the stimulable phosphor sheet is thereafter scanned with the excitation light, the stimulable phosphor layer emits stimulable emission light indicating radiation image information.

Here, in the radiation image information reading apparatus used in the above-mentioned radiation image recording and reproducing system,
From the viewpoints of shortening the reading time of stimulating light, reducing the size and cost of the device, CC
It has been proposed to apply a line sensor made of D or the like (JP-A-60-111568, JP-A-60-236354,
No. 101540).

The radiation image information reading apparatus of this type basically includes an excitation light irradiating means for linearly irradiating a part of the stimulable phosphor sheet storing the radiation image information with excitation light, and the stimulable fluorescent light. A line sensor in which a plurality of photoelectric conversion elements are arranged side by side along a linear excitation light irradiation portion of the body sheet; and one of the line sensor and the excitation light irradiation means and the stimulable phosphor sheet with respect to the other. And a sub-scanning means for relatively moving in the direction (sub-scanning direction) intersecting with the length direction (main scanning direction) of the excitation light irradiated portion.

As described above, the excitation light irradiating means for linearly irradiating the stimulable phosphor sheet with the excitation light may be a device which emits a so-called fan beam-like excitation light. The thin beam may be deflected and scanned linearly on the stimulable phosphor sheet.

[0013]

As described above, one laser diode (semiconductor laser) is used as the excitation light irradiating means for emitting the excitation light in the form of a fan beam from the viewpoint of miniaturization and cost reduction of the apparatus. Is thought to be. In that case, in order to secure a large main scanning width, the laser beam emitted in a divergent light state from the laser diode is converged in the sub-scanning direction to be linear, while in the main scanning direction intersecting that direction. An expanding lens optical system is also applied.

However, in such a conventional configuration, in order to secure a large main scanning width, the distance from the laser diode to the stimulable phosphor sheet must be set to be considerably long. It has been recognized that it is difficult to reduce the size.

The laser beam emitted from the laser diode has an intensity distribution referred to as a so-called Gaussian distribution in which the maximum intensity is obtained at the center of the beam and the intensity decreases toward the periphery of the beam. Like one
In a conventional radiation image information reading apparatus using two laser diodes as excitation light irradiation means, there is also a problem that the excitation light intensity becomes extremely non-uniform over the main scanning direction.

Accordingly, an object of the present invention is to provide a radiation image information reading apparatus using a laser diode as an excitation light source, to sufficiently reduce the size of the apparatus and to make the excitation light intensity distribution uniform in the main scanning direction.

[0017]

According to the first radiographic image information reading apparatus of the present invention, as described above, the excitation light is linearly applied to a part of the stimulable phosphor sheet on which the radiographic image information is stored. Excitation light irradiating means for irradiating, a line sensor in which a plurality of photoelectric conversion elements are juxtaposed along a linear excitation light irradiating portion of the stimulable phosphor sheet, and the line sensor and the excitation light irradiating means And a sub-scanning means for moving one of the stimulable phosphor sheets relative to the other in a direction intersecting with the length direction of the excitation light irradiation portion. The excitation light irradiating means is such that the laser beams as excitation light emitted from each other are continuous with each other in the length direction of the excitation light irradiating portion, and the beam spreading direction perpendicular to the bonding surface is substantially the same as the continuous direction of the beams. A plurality of laser diodes arranged in the matching direction, and the laser beams emitted from these laser diodes are condensed only in a plane perpendicular to the direction of their continuation, and are focused on the stimulable phosphor sheet. And a cylindrical lens that converges in the above.

In the second radiation image information reading apparatus according to the present invention, similarly to the above, a part of the stimulable phosphor sheet on which the radiation image information is stored is irradiated with the excitation light linearly. Means, a line sensor in which a plurality of photoelectric conversion elements are arranged side by side along a linear excitation light irradiation portion of the stimulable phosphor sheet, the line sensor and the excitation light irradiation means, A sub-scanning means for moving one of the phosphor sheets relative to the other in a direction intersecting with the longitudinal direction of the excitation light irradiation portion, wherein the excitation light irradiation means However, there are a plurality of laser diodes arranged so that laser beams as excitation light emitted from the laser beams are connected to each other in the longitudinal direction of the excitation light irradiation portion, and the laser diodes emitted from these laser diodes are respectively provided. A laser beam condensed only in a plane perpendicular to the direction of the series thereof and converged on the stimulable phosphor sheet, and disposed between the cylindrical lens and the plurality of laser diodes. And an optical element for scattering the laser beam emitted from each of the laser diodes.

Further, in the third radiation image information reading apparatus according to the present invention, similarly to the above, the excitation light irradiation for linearly irradiating a part of the stimulable phosphor sheet on which the radiation image information is stored with the excitation light is performed. Means, a line sensor in which a plurality of photoelectric conversion elements are arranged side by side along a linear excitation light irradiation portion of the stimulable phosphor sheet, the line sensor and the excitation light irradiation means, A sub-scanning means for moving one of the phosphor sheets relative to the other in a direction intersecting with the longitudinal direction of the excitation light irradiation portion; The arrangement state is the same as that in the first radiation image information reading apparatus, and the optical element for scattering the laser beam used in the second radiation image information reading apparatus is provided. The one in which the features.

In each of the radiation image information reading apparatuses according to the present invention, the plurality of laser diodes are arranged so that the laser beams emitted from the adjacent ones of the plurality of laser diodes are continuous with overlapping portions. Is desirable.

The stimulable phosphor sheet to be read by the radiation image information reading apparatus according to the present invention may be a stimulable phosphor sheet having both functions of radiation absorption and energy storage as described above. Alternatively, it may have a stimulable phosphor layer dedicated to energy storage.

The latter type of stimulable phosphor sheet may have the above-mentioned radiation absorbing phosphor layer in addition to the stimulable phosphor layer dedicated to energy storage, or Instead of having such a radiation-absorbing phosphor layer, a phosphor screen having the same radiation-absorbing phosphor layer may be used.

[0023]

In the first radiation image information reading apparatus according to the present invention, the plurality of laser diodes constituting the excitation light irradiating means are arranged such that the laser beams as the excitation light emitted from each other have the lengths of the excitation light irradiating portions. Since they are arranged so as to be continuous in the direction, a continuous irradiation light irradiation portion, that is, a main scanning width is secured as a whole by the continuous connection. Therefore, even when a large main scanning width is to be ensured, the distance between each laser diode and the stimulable phosphor sheet can be set relatively short, whereby a sufficient miniaturization of the device can be realized. You.

In the first radiation image information reading apparatus, the plurality of laser diodes constituting the excitation light irradiating means are arranged in such a direction that the beam spread direction perpendicular to the joint surface substantially coincides with the continuous direction of the beams. Since it is provided, the effect of miniaturization of the apparatus by that is also obtained.

That is, in a general laser diode, the beam divergence angle θ _{H in the} direction parallel to the bonding surface is 8 to 10
°, whereas the beam divergence angle θ _{V in the} direction perpendicular to the joint surface is generally very large, about 20 to 25 °,
If each laser diode is arranged in the above-described direction, the laser beam will be incident on the stimulable phosphor sheet in a state where the laser beam spreads more than in the case where the laser diodes are arranged in other directions. . If so, even when a large main scanning width is to be secured, the distance between the laser diode and the stimulable phosphor sheet can be set shorter, thereby further reducing the size of the device. .

Further, when a plurality of laser diodes are arranged in the above-mentioned direction to increase the spread of the laser beam, when the laser beam is arranged in another direction, that is, when the spread of the laser beam is smaller than that. As compared with, the beam intensity (excitation light intensity) on the main scanning line changes more gradually. Therefore, in consideration of securing a common main scanning width in the two cases, the excitation light intensity within the main scanning width becomes more uniform in the former case, that is, in the present invention.

On the other hand, also in the second radiation image information reading apparatus according to the present invention, the plurality of laser diodes constituting the excitation light irradiating means are arranged so that the laser beams as the excitation light emitted from each other have the same length as the excitation light irradiating portion. Since they are arranged so as to be continuous in the direction, as in the case of the first radiation image information reading apparatus, a long excitation light irradiation portion, that is, a main scanning width as a whole, that is, a main scanning width is secured by the continuous connection.
Therefore, even when a large main scanning width is to be ensured, the distance between each laser diode and the stimulable phosphor sheet can be set relatively short, whereby a sufficient miniaturization of the device can be realized. You.

Further, in the second radiation image information reading apparatus according to the present invention, an optical element for scattering laser beams emitted from the laser diodes is provided between the cylindrical lens and the plurality of laser diodes. Therefore, these laser beams are incident on the stimulable phosphor sheet in a state of being spread greatly. Thus, the distance between the laser diode and the stimulable phosphor sheet can be set shorter, which can further reduce the size of the device.

Further, in the second radiation image information reading apparatus, since the laser beams emitted from the plurality of laser diodes are scattered by the optical elements,
The original intensity distribution (Gaussian distribution) of the laser beam is disturbed by scattering. Therefore, the intensity of the laser beam incident on the stimulable phosphor sheet as excitation light is made more uniform than in the case where the laser beam is not scattered.

Further, in the third radiation image information reading apparatus according to the present invention, the arrangement state of the plurality of laser diodes is made the same as in the first radiation image information reading apparatus, and the second radiation image information is read. Since the optical elements for scattering the laser beam used in the reading device are provided, the effect of miniaturization of the device by these configurations can be synergistically obtained.

In each of the radiation image information reading apparatuses according to the present invention, the plurality of laser diodes are arranged so that the laser beams emitted from the adjacent ones of the laser diodes are overlapped with each other and continue. In this case, the effect of making the excitation light intensity uniform over the main scanning direction can be obtained more remarkably.

That is, the laser beam emitted from the laser diode has an intensity distribution referred to as the Gaussian distribution described above, that is, an intensity distribution in which the maximum intensity is obtained at the center of the beam and the intensity decreases toward the periphery of the beam. ing. Therefore, if the two laser beams have overlapping portions as described above, the peripheral portion of the originally low intensity beam overlaps with the peripheral portion of the adjacent beam, and the beam intensity (excitation light intensity) of that portion increases. As a result, the excitation light intensity in the main scanning direction is made uniform.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a radiation image information reading apparatus according to a first embodiment of the present invention. FIGS. 2 and 3 are side views of a reading optical system of the radiation image information reading apparatus. The shape and the front shape are shown.

As shown in FIG. 1, the present apparatus comprises a laser diode array 11 for emitting a fan beam-like excitation light 10, a cylindrical lens 12 for condensing the excitation light 10 only in the plane shown in FIG. A lens array 15 for condensing photostimulated luminescent light 14 emitted from a portion of the stimulable phosphor sheet 13 that is linearly irradiated with light 10, and an optical path of the photostimulated luminescent light 14 passing through the lens array 15. Disposed excitation light cut filter 16
And the stimulated emission light transmitted through this excitation light cut filter 16
A CCD line sensor 17 for detecting the stimulable phosphor 14 and a sub-feeder for feeding the stimulable phosphor sheet 13 at a constant speed in the direction of the arrow Y, that is, in the direction orthogonal to the length direction (the direction of the arrow X) of the excitation light irradiated portion on the sheet 13. And an endless belt 18 as scanning means.

Further, an amplifier 20 amplifies the analog light detection signal S output from the CCD line sensor 17.
An A / D converter 21 for digitizing the amplified photodetection signal S; an image processing device 22 for image processing the digital image signal D output from the A / D converter 21; An image reproducing device 23 to which the image signal D is input is provided.

As shown in FIG. 3, the laser diode array 11 includes a plurality of laser diodes 11a, 11b, 11c,... Having an oscillation wavelength of 660 nm arranged in a line. Each laser diode 11a, 11b, 11c ...
Excitation light 10a, 10b, 10c in a divergent light state emitted from ...
Are condensed in only one direction by the cylindrical lens 12 to form a fan beam, and the excitation light 10 in which the fan beams are continuous irradiates a part of the stimulable phosphor sheet 13 linearly.

The plurality of laser diodes 11a, 11
are arranged in such a direction that the beam diverging direction perpendicular to the respective joining surfaces coincides with the continuous direction of the excitation lights 10a, 10b, 10c. That is, the beam divergence angles of the excitation lights 10a, 10b, 10c... Shown in FIG.
Is a direction perpendicular divergence angle theta _V on the bonding surface.

As shown in a plan view in FIG. 4, the CCD line sensor 17 has a large number of sensor chips (photoelectric conversion elements) 17a arranged in a line. In this example, the light receiving width of the CCD line sensor 17 in the direction orthogonal to the direction in which the sensor chips are arranged, that is, the width W of the sensor chip 17a is about 100 μm.

In the CCD line sensor 17, the sensor chips 17a are arranged in such a direction that the sensor chips 17a are arranged along the length direction (the direction of the arrow X) of the portion irradiated with the excitation light on the stimulable phosphor sheet 13 in FIG. Note that the CCD line sensor 17 may be configured by connecting a plurality of line sensors in the length direction in order to correspond to the stimulable phosphor sheet 13 having a large width.

On the other hand, the lens array 15 is provided as shown in FIG.
As shown in (2), a front shape and a side shape, for example, a number of gradient index lenses 15a, 15b, 15c, 15d,.
… Are arranged in a line. Each of the gradient index lenses 15a, 15b, 15c, 15d... Collects the stimulated emission light 14 emitted from the stimulable phosphor sheet 13 and guides it to the CCD line sensor 17 as shown in FIG. . The lens array 15 includes gradient index lenses 15a, 15b, 15c, and 15d.
Are arranged in a direction aligned on the stimulable phosphor sheet 13 along the length direction (the direction of the arrow X) of the portion irradiated with the excitation light.

The operation of the radiation image information reading apparatus having the above configuration will be described below. The stimulable phosphor sheet 13 includes
Radiation image information of the subject is accumulated and recorded by irradiating radiation transmitted through the subject, and the sheet 13 is fed by the endless belt 18 at a constant speed in the direction of arrow Y. At the same time, the excitation light 10 emitted from the laser diode array 11 irradiates a part of the stimulable phosphor sheet 13 linearly.

From the portion of the stimulable phosphor sheet 13 which has been irradiated with the excitation light 10, stimulable luminescence light 14 of an amount corresponding to the radiation image information stored and recorded diverges. For example, the blue stimulating light 14 is condensed by the lens array 15 and guided to the CCD line sensor 17, and is photoelectrically detected by the CCD line sensor 17. The excitation light 10 reflected by the stimulable phosphor sheet 13 and traveling toward the CCD line sensor 17 is cut by an excitation light cut filter 16.

The CCD line sensor 17 outputs an analog light detection signal S corresponding to the amount of the stimulating light 14 (that is, indicating the radiation image information). The light detection signal S is amplified by the amplifier 20 and then converted into a digital image signal D in the A / D converter 21.

The digital image signal D is then subjected to image processing such as gradation processing in the image processing device 22, and then sent to the image reproducing device 23, where the radiation image recorded on the stimulable phosphor sheet 13 is stored. To be played. The image reproducing device 23 may be a display means such as a CRT display device, or a recording device for performing optical scanning recording on a photosensitive film.

Next, the spread state and intensity distribution of the excitation lights 10a, 10b, 10c... Will be described in detail with reference to FIG. In this embodiment, each of the laser diodes 11a, 11b, 11c,... Constituting the laser diode array 11 has an output of 50 mW, and 30 of them are used as an example. Thus, a large number of laser diodes 11
a, 11b, 11c,..., and the stimulable phosphor sheet 13 connected with the excitation lights 10a, 10b, 10c,.
In this case, as long as the main scanning width is the same, compared to the case where only one laser diode is used, the present embodiment naturally has a larger distance from the laser diode to the stimulable phosphor sheet 13 as long as the main scanning width is the same. The distance can be shortened. Thereby, the radiation image information reading device can be sufficiently reduced in size.

Each of the laser diodes 11a, 11b, 11c
In FIG. 3, the beam divergence angle θ _{V in the} direction perpendicular to the bonding surface shown in FIG. 3 is 22 °, whereas the beam divergence angle θ _{H in the} direction parallel to the bonding surface is 10 °. In this embodiment, the beam divergence angle θ is as large as 22 °.
_The beam spread direction in which _V is obtained depends on the excitation light 10a, 10a.
Since the laser diodes 11a, 11b, 11c,... are arranged in a direction coinciding with the continuous direction of the b, 10c,.
10c are incident on the stimulable phosphor sheet 13 in a state of being greatly expanded. If this is the case, the distance between the laser diodes 11a, 11b, 11c,... And the stimulable phosphor sheet 13 can be set shorter, thereby further reducing the size of the device.

Further, the laser diodes 11a, 11b, 11
are arranged in the above-mentioned directions, and the excitation lights 10a, 10b, 10c are arranged.
When the spread of c is larger, the beam intensity on the main scanning line is smaller than when the spread is smaller, ie, when the spread of the excitation lights 10a, 10b, 10c is smaller. (Excitation light intensity) changes more slowly. FIGS. 6A and 6B show this by taking one laser diode 11a as an example.

FIG. 1A shows a case where the laser diode 11a is arranged as in the present embodiment, and FIG. 2B shows that the laser diode 11a The intensity distribution of the excitation light 10a in the main scanning direction X on the stimulable phosphor sheet 13 is shown in a case where the excitation light 10a is arranged in a direction coinciding with the continuous direction of 10c. As shown here, in consideration of securing the same main scanning width Ls in each case, the intensity of the excitation light 10a within the main scanning width Ls is more uniform in the present embodiment. It is clear that

As shown in FIG. 3, in this embodiment, the laser diodes 11a, 11b, 11c... Are pump light emitted from adjacent ones of them (that is, for example, the pump light 10a and the pump light 10b, Light 10b and excitation light 10c
...) Are arranged so as to be continuous with an overlapping portion. Excitation light 10a, 10b, 10c also shown in FIG.
As is clear from the intensity distribution over the main scanning direction of..., If the two excitation lights overlap each other, the beam periphery of the originally low-intensity excitation light and the beam periphery of the adjacent excitation light are adjacent to each other. Overlapping, the intensity of the excitation light at that portion is increased as shown by the broken line in the figure, and the intensity of the excitation light over the main scanning direction is made uniform.

If it is difficult to make the excitation light intensity uniform in the main scanning direction completely, the digital image signal D may be corrected so as to compensate for the non-uniformity of the excitation light intensity.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 7 shows the front shape of the reading optical system of the radiation image information reading apparatus according to the second embodiment of the present invention. In FIG. 7, elements that are the same as the elements in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted unless necessary (the same applies hereinafter).

The radiation image information reading apparatus of the present embodiment
Compared to the device of the first embodiment described above, a plurality of laser diodes 11
.. and the cylindrical lens 12 are provided with diffraction gratings 30 for scattering the excitation lights 10a, 10b, 10c,. In this configuration, the excitation lights 10a, 10b, 10c.
And is incident on the cylindrical lens 12 in a state of being scattered to some extent.

Therefore, in this example, the excitation lights 10a, 10b,
10c are incident on the stimulable phosphor sheet 13 in a state of being greatly expanded as compared with the first embodiment. Therefore, as compared with the first embodiment, if the main scanning width to be secured is the same, the laser diode 11
, and the distance between the stimulable phosphor sheet 13 can be set shorter, so that the device can be further miniaturized.

Further, in the radiation image information reading apparatus of the second embodiment, since the excitation lights 10a, 10b, 10c... Are diffracted and scattered by the diffraction grating 30, respectively,
The intensity distribution (Gaussian distribution) originally possessed by a, 10b, 10c,... is disturbed by scattering. Therefore, the intensity of the excitation lights 10a, 10b, 10c,... Incident on the stimulable phosphor sheet 13 can be made more uniform as compared with the case where the scattering is not performed.

In the second embodiment, the first
As in the first embodiment, a larger beam divergence angle θ _V
The beam spread directions in which the laser beams are obtained are the excitation light beams 10a, 10b, 10
c. The laser diode is oriented in the same direction as the
.. Are arranged, but when the laser diodes 11a, 11b, 11c... Are arranged in other directions, the excitation light 10a, 10b, 10c is
.. May be scattered, and in this case, the same effect as described above can be obtained.

However, the laser diodes 11a, 11b, 11
.. are arranged in the above-described directions, and the diffraction grating 30 is further provided thereon, so that the effects of both configurations can be obtained synergistically.

As an optical element for scattering the excitation lights 10a, 10b, 10c..., A large number of optical fibers are bundled in addition to the diffraction grating 30 described above, as in the third embodiment shown in FIG. A fiber bundle 40 arranged so that the excitation lights 10a, 10b, 10c... Traverse each optical fiber, or a microlens array or the like can also be used.

The stimulable phosphor sheet to be read by the radiation image information reading apparatus of the present invention may be a stimulable phosphor sheet having both a radiation absorbing function and an energy storing function, or The above-mentioned Japanese Patent Application No. 11-3 was provided with a phosphor layer dedicated to storage to separate both functions.
It may be the stimulable phosphor sheet disclosed in 72978. When the stimulable phosphor sheet provided with the phosphor layer dedicated to storage is used, the detection quantum efficiency in radiation image formation, that is, the radiation absorptance, the stimulated emission efficiency, and the efficiency of taking out the stimulated emission light are generally increased. Therefore, the image quality of the reproduced radiation image can be improved.

Further, the stimulable phosphor sheets to be read have radiation energy absorption characteristics different from each other.
A stimulable phosphor for radiation energy subtraction, which has two stimulable phosphor layers and can radiate two types of stimulated emission light carrying the radiation image information recorded in each layer from the front and back surfaces of the sheet. It may be a body sheet.

In this case, the radiation image information reading apparatus of the present invention includes line sensors on both sides of the stimulable phosphor sheet, and outputs image signals indicating image information read from both sides of the stimulable phosphor sheet. A reading unit for performing a subtraction process by associating pixels on the front and back surfaces of the sheet may be provided.

The above-mentioned stimulable phosphor sheet for radiation energy subtraction has a structure in which, for example, an excitation light-reflecting partition member extending in the thickness direction of the sheet is subdivided into a number of micro-chambers. Oriented stimulable phosphor sheets can also be used.

Further, in the embodiment described above, the stimulable phosphor sheet 13 is conveyed at a constant speed by the endless belt 18 for excitation light sub-scanning. The present invention is not limited to this, and may employ a device that transports the stimulable phosphor sheet 13 using a roller, or a device that moves the excitation light irradiating unit and the line sensor relative to the fixed stimulable phosphor sheet 13. It is also possible.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a radiation image information reading apparatus according to a first embodiment of the present invention;

FIG. 2 is a side view showing a reading optical system of the radiation image information reading apparatus shown in FIG. 1;

FIG. 3 is a front view of the reading optical system shown in FIG. 2;

FIG. 4 is a plan view of a line sensor used in the radiation image information reading apparatus.

5 is a front view (1) and a side view (2) of a lens array used in the radiation image information reading apparatus of FIG.

FIG. 6 is an explanatory diagram illustrating an effect of the present invention.

FIG. 7 is a front view showing a reading optical system of a radiation image information reading apparatus according to a second embodiment of the present invention.

FIG. 8 is a front view showing a reading optical system of a radiation image information reading apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 10a, 10b, 10c Excitation light 11 Laser diode array 11a, 11b, 11c Laser diode 12 Cylindrical lens 13 Storage phosphor sheet 14 Stimulated emission light 15 Lens array 15a, 15b, 15c Refractive index distribution type lens 16 Excitation light cut filter 17 CCD line sensor 17a Sensor chip of CCD line sensor 18 Endless belt 20 Amplifier 21 A / D converter 22 Image processing device 23 Image reproducing device 30 Diffraction grating 40 Fiber bundle

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 1/04 H04N 1/04 101 101 EF term (reference) 2G083 AA03 BB04 DD17 EE10 2H013 AC04 AC05 5B047 AA17 AB02 BA01 BB02 BC01 BC05 BC08 BC12 5C051 AA01 BA02 DA03 DB01 DB22 DB25 DB30 DC02 DC04 DC05 DC07 5C072 AA01 BA01 CA06 DA02 DA07 DA16 DA21 EA05 VA01

Claims (4)

[Claims] 1. Exciting light irradiating means for irradiating a part of a stimulable phosphor sheet on which radiation image information is accumulated and recorded with excitation light in a linear manner; A line sensor in which a plurality of photoelectric conversion elements are juxtaposed along the line, the line sensor and the excitation light irradiating unit, and one of the stimulable phosphor sheet relative to the other. A radiation image information reading apparatus comprising: a sub-scanning unit that moves in a direction intersecting with the length direction of the light irradiation part. A plurality of laser diodes arranged so as to be continuous in the longitudinal direction of the laser diode and in a direction in which a beam spread direction perpendicular to the bonding surface substantially coincides with the continuous direction of the beams; A laser beam converged on the stimulable phosphor sheet by condensing the laser beams respectively emitted only from within a plane perpendicular to the direction of their continuity. Information reading device. 2. An excitation light irradiating means for linearly irradiating a part of a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and a linear excitation light irradiating part of the stimulable phosphor sheet. A line sensor in which a plurality of photoelectric conversion elements are juxtaposed along the line, the line sensor and the excitation light irradiating unit, and one of the stimulable phosphor sheet relative to the other. A radiation image information reading apparatus comprising: a sub-scanning unit that moves in a direction intersecting with the length direction of the light irradiation part. And a plurality of laser diodes arranged so as to be continuous in the longitudinal direction, and laser beams emitted from these laser diodes, respectively, only in a plane perpendicular to the direction in which they are connected. A cylindrical lens that emits light and converges on the stimulable phosphor sheet; and an optical element that is disposed between the cylindrical lens and the plurality of laser diodes and scatters laser beams emitted from the laser diodes. A radiation image information reading apparatus comprising: 3. Excitation light irradiating means for irradiating a part of a stimulable phosphor sheet on which radiation image information is accumulated and recorded with excitation light in a linear manner, and a linear excitation light irradiating part of the stimulable phosphor sheet. A line sensor in which a plurality of photoelectric conversion elements are juxtaposed along the line, the line sensor and the excitation light irradiating unit, and one of the stimulable phosphor sheet relative to the other. A radiation image information reading apparatus comprising: a sub-scanning unit that moves in a direction intersecting with the length direction of the light irradiation part. A plurality of laser diodes arranged so as to be continuous in the longitudinal direction of the laser diode and in a direction in which a beam spread direction perpendicular to the bonding surface substantially coincides with the continuous direction of the beams; A laser beam emitted from each of the above-described laser beams is focused only in a plane perpendicular to the direction of the series thereof and converges on the stimulable phosphor sheet; and a cylindrical lens and the plurality of laser diodes. An optical element interposed between the laser diodes for scattering laser beams emitted from the laser diodes. 4. The plurality of laser diodes are arranged such that laser beams emitted from adjacent ones of the plurality of laser diodes are continuous with overlapping portions. Claims 1 to 3
The radiation image information reading device according to claim 1.