JP3360813B2 - Radiation image information reader - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image information reading device, and more particularly to a radiation image information reading device for reading stimulated emission light emitted from a stimulable phosphor sheet with a line sensor.

[0002]

2. Description of the Related Art A part of this radiation energy is accumulated when it is irradiated with radiation, and when it is subsequently irradiated with excitation light such as visible light or laser light, a stimulable phosphor that exhibits stimulated emission according to the accumulated radiation energy. (Stimulable phosphor) is used to temporarily store and record radiation image information of a subject such as a human body on a sheet-shaped stimulable phosphor sheet in which a stimulable phosphor is laminated on a support. Excitation light such as laser light is deflected and scanned for each pixel to sequentially generate stimulated emission light from each pixel, and the obtained stimulated emission light is photoelectrically sequentially read by a photoelectric reading unit to obtain an image signal. A radiation image recording / reproducing system that irradiates the stimulable phosphor sheet after reading the image signal with erasing light to release the radiation energy remaining on the sheet has been widely put into practical use.

The image signal obtained by this system is subjected to image processing such as gradation processing and frequency processing suitable for observation and interpretation, and the image signal after these processing is used as a visible image for diagnosis. Recorded on film or high-definition CR
It is displayed on T and used for diagnosis by a doctor or the like. on the other hand,
The stimulable phosphor sheet which has been irradiated with the erasing light and has released the residual radiation energy is capable of accumulating and recording radiation image information again, and can be repeatedly used.

Here, in the radiation image information reading apparatus used in the radiation image recording / reproducing system described above,
Fluorescent lamps, cold cathode fluorescent lamps, LED arrays, etc. that linearly irradiate a sheet with excitation light as an excitation light source from the viewpoints of shortening the reading time of stimulated emission light, downsizing of the device, and cost reduction Using a line light source, as a photoelectric reading means, while using a line sensor in which a large number of photoelectric conversion elements are arranged along the length direction of the linear portion of the sheet irradiated with excitation light by the line light source, There has been proposed a configuration including a scanning means for moving the line light source and the line sensor relative to the sheet in a direction substantially orthogonal to the lengthwise direction of the linear portion (Japanese Patent Laid-Open No. Sho 60).
-111568, 60-236354, JP-A-1-101540, etc.).

[0005]

However, in the above-described fluorescent lamp, cold cathode fluorescent lamp, or LED array, the emitted light is likely to spread, and the intensity of the emitted light is sufficient to obtain an image with a good S / N. It is not possible to excite the stimulable phosphor sheet with sufficient excitation energy.

The present invention has been made in view of the above circumstances, and enhances the directivity of excitation light emitted from a line light source and improves the intensity of the emitted light to obtain an image with excellent S / N. It is an object of the present invention to provide a radiation image information reading device capable of performing the above.

[0007]

The radiation image information reading apparatus of the present invention irradiates the radiation image information accumulated and recorded on the stimulable phosphor sheet with a linear laser beam emitted from a broad area laser. Is read by.

That is, the radiation image information reading apparatus of the present invention has a linear light source 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 light source for the sheet. A line sensor in which a large number of photoelectric conversion elements are arranged, which performs photoelectric conversion by receiving stimulated emission light emitted from the irradiated portion or the portion on the back surface side of the sheet corresponding to this irradiated portion, Scanning means for moving the line light source and the line sensor relative to the sheet in a direction different from the linear length direction, and the output of each photoelectric conversion element forming the line sensor is moved. in the radiation image information reading apparatus that includes a sequential read reading means in response to said line light source, Ri Oh broad area laser which emits the excitation light into a linear shape, the Burodoe Excitation light emitted from Areza
The longitudinal length of the irradiation area on the sheet due to
Longer than one side of the serial sheet or is characterized in equivalent der Rukoto.

The laser light (excitation light) emitted from the broad area laser may be continuously emitted, or may be pulsed light emitted in a pulsed state in which emission and stop are repeated. However, from the viewpoint of noise reduction, pulsed light with high output is desirable. The oscillation wavelength of the broad area laser is specifically 600 to 1000 nm, preferably 600 to 700 nm.

[0010] length of the long axis of the irradiation area of the stimulable phosphor sheet by the excitation light emitted from the broad area laser, Ru long or equivalent der than one side of the stimulable phosphor sheet if Alternatively, the excitation light may be emitted while being inclined with respect to the side of the sheet.

Here, the broad area laser means a laser in which emitted laser light itself is linear. Specifically, the active layer has a length in the major axis direction of 50 to 1000 μm and a minor axis direction. A broad area semiconductor laser, which is a semiconductor laser having a length of 0.1 to 10 μm, is preferable. However, the broad area laser in the present invention is not limited to this broad area semiconductor laser, and may be any other laser as long as the emitted laser light itself is linear.

Further, in order to further improve the degree of converging of the excitation light emitted from the broad area laser on the sheet, a cylindrical lens, a slit, a selfoc lens (rod lens) array, an optical fiber bundle, etc.
Alternatively, a combination of these may be arranged between the light source and the sheet.

The width of the excitation light emitted from the broad area laser on the sheet is 10 to 4000 μm.
Is appropriate.

Further, in order to enhance the degree of condensing of the stimulated emission light emitted from each part of the sheet on the line sensor, the object plane and the image plane are constituted by an image-forming system having a one-to-one correspondence. A SELFOC lens (registered trademark; omitted below) array, a gradient index lens array such as a rod lens array, a cylindrical lens, a slit, an optical fiber bundle, or a combination thereof is arranged between the sheet and the line sensor. It is desirable to install it.

The direction in which the scanning means moves the broad area laser and the line sensor relative to the sheet (direction different from these length directions) is substantially the same in these length directions (long axis direction). It is desirable that the directions are orthogonal to each other, that is, the minor axis direction, but it is not limited to this direction. For example, as described above, in the configuration in which the broad area laser or the line sensor is longer than one side of the sheet, the sheet Of the broad area laser and the line sensor may be moved in an oblique direction deviating from a direction substantially orthogonal to the longitudinal direction within a range in which the excitation light can be uniformly irradiated over substantially the entire surface of For example, the moving direction may be changed in a zigzag manner.

Further, between the seat and the line sensor,
It is preferable to provide an excitation light cut filter (sharp cut filter, bandpass filter) that transmits stimulated emission light but does not transmit excitation light to prevent the excitation light from entering the line sensor.

As the line sensor, an amorphous silicon sensor, a CCD sensor, a CCD with a back illuminator, a MOS image sensor or the like can be applied.

The line sensor may be one in which a large number of photoelectric conversion elements are arranged only in the length direction (long axis direction) thereof, or a plurality of photoelectric conversion elements may be arranged in the short axis direction orthogonal thereto. May be provided, and in this case, the plurality of photoelectric conversion elements are not limited to a matrix arrangement in which the photoelectric conversion elements are arranged in one straight line in both the major axis direction and the minor axis direction. , An array that is arranged in a straight line in the long axis direction but is arranged in a zigzag pattern in the short axis direction, or an array that is arranged in a straight line in the short axis direction but is arranged in a zigzag pattern in the long axis direction,
It may be arranged in a zigzag arrangement in both axial directions.

[0019] The radiation image information reading apparatus of the present invention is thus the line sensor is respectively linear in the minor axis direction orthogonal longitudinal and to a plurality of photoelectric conversion elements are arranged together with the orthogonal read handle stage, in the longitudinal direction at each position which is moved by the scanning means
It is also possible to employ a configuration in which the output of each of the plurality of photoelectric conversion elements in the direction to be processed is further provided with a processing unit that performs processing by correlating the parts of the sheet. In such a configuration, stimulated emission Even when the light emission line width is wider than the width of the photoelectric conversion element, the line sensor as a whole can receive light over substantially the entire line width of the stimulated emission light, and the light is received by each photoelectric conversion element. The light receiving efficiency can be improved by correlating the generated signal with the position of the sheet and performing arithmetic processing such as addition processing by the arithmetic means further included in the reading means.

In the structure in which the number of photoelectric conversion elements is increased to such an extent that the transfer rate affects, a memory element corresponding to each photoelectric conversion element is provided to temporarily store the charges accumulated in each photoelectric conversion element. The memory may be stored in each memory element, and the charge may be read from each memory element during the next charge accumulation period, so that the charge accumulation time can be prevented from being shortened due to the increase in the charge transfer time.

Further, it is desirable that the number of photoelectric conversion elements arranged in the long axis direction of the line sensor is 1000 or more,
The length of the line sensor is preferably longer than or equal to one side of the sheet on its light receiving surface. When it is longer, the line sensor is tilted with respect to the side of the sheet to perform photoelectric detection. You may do it.

Further, the broad area laser and the line sensor may be arranged on the same surface side of the sheet, or may be separately arranged on opposite surface sides. However, in the case of adopting a configuration that is arranged separately, the support of the sheet is stimulated so that the stimulated emission light is transmitted to the side of the sheet opposite to the side on which the excitation light is incident. It must be light transmissive.

It is desirable that the exciting light applied to the sheet has a light amount within a range in which its power does not change.
Even if the light amount is within the range where power fluctuation can occur, the light amount of the excitation light is monitored by the monitoring means, and based on this monitoring result, when power fluctuation occurs, the speed is higher than the photoelectric conversion speed by the photoelectric conversion element. In addition, the broad area laser may be modulated by the broad area laser modulating means so that the power of the broad area laser becomes constant to suppress the influence of power fluctuation.

As the arithmetic processing, specifically, simple addition processing, weighted addition processing, or other various arithmetic processing can be applied. Therefore, the addition means may be applied as the calculation means for the simple addition processing or the weighted addition processing.

[0025]

According to the radiation image information reading apparatus of the present invention, the radiation image information accumulated and recorded on the stimulable phosphor sheet is irradiated with the laser beam which is the linear coherent light emitted from the broad area laser. Since the reading is performed by performing the reading, the directivity of the emitted excitation light is high and the intensity of the emitted light is higher than that of the conventional radiation image information reading device using a fluorescent lamp, a cold cathode fluorescent lamp, or an LED array as a light source. Since it is strong, it is possible to apply higher excitation energy to the stimulable phosphor sheet, and as a result, S
Images with high / N can be obtained.

A radiation image information reading apparatus in which the line sensor is constructed by arranging a plurality of photoelectric conversion elements in the lengthwise direction of the linear stimulated emission light emitted from the sheet and in the direction orthogonal thereto. According to the above, even if the light receiving width of each photoelectric conversion element is shorter than the line width of the stimulated emission light (the line width on the light receiving surface of the photoelectric conversion element), the line sensor as a whole has substantially the entire line width of the stimulated emission light. Since the light can be received over the entire range, the light receiving efficiency can be improved. And
The output of each photoelectric conversion element at each position where the sheet or the sensor is moved by the scanning means is subjected to arithmetic processing such as addition processing by using arithmetic means such as addition means and corresponding the parts of the sheet. It is possible to increase the light collection efficiency for each part of the sheet. Moreover, since the light receiving width of each photoelectric conversion element is not increased to increase the light receiving size, the resolution does not decrease, and the desired resolution can be secured.

The radiation image information reading apparatus of the present invention adopts a configuration using a line sensor as the photoelectric reading means, in contrast to the conventional radiation image information reading apparatus using the photoelectric reading means instead of the line sensor. As a result, the reading time of stimulated emission light can be shortened, the device can be made compact, and the cost can be reduced by reducing mechanical scanning optical parts and the like.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a radiation image information reading apparatus of the present invention will be described below with reference to the drawings.

FIG. 1A is a perspective view showing an embodiment of the radiation image information reading apparatus of the present invention, and FIG. 1B is a sectional view taken along line I-I of the radiation image information reading apparatus shown in FIG. FIG. 2 is a sectional view showing the detailed configuration of the line sensor 20 of the reading apparatus shown in FIG.

The illustrated radiation image information reading apparatus is a stimulable phosphor sheet (hereinafter, referred to as a stimulable phosphor sheet in which radiation image information is accumulated and recorded).
A scanning belt 40 on which a sheet 50) is placed and conveyed in the direction of the arrow Y, a broad area semiconductor that emits a linear laser beam L having a line width of about 100 μm and an oscillation wavelength of 600 to 700 nm substantially parallel to the surface of the sheet 50. Laser (hereinafter referred to as BLD) 11, B
An optical system 12 composed of a combination of a collimator lens that collects the linear laser light L emitted from the LD 11 and a toric lens that expands the beam in only one direction, and is arranged at an angle of 45 degrees with respect to the surface of the sheet 50. Further, the dichroic mirror 14, which is set so as to reflect the laser light L and transmit the stimulated emission light M which will be described later, and the linear laser light L reflected by the dichroic mirror 14, are indicated by the arrow X on the sheet 50.
The stimulated emission light according to the stored and recorded radiation image information, which is emitted from the sheet 50 while being condensed in a linear shape (line width approximately 100 μm) extending along the direction, is emitted from the sheet 50. A gradient index lens array in which M is a parallel light flux (a lens in which a large number of gradient index lenses are arranged, hereinafter referred to as a first SELFOC lens array)
15, and the photostimulated luminescence light M that has been made into a parallel light flux by the first SELFOC lens array 15 and transmitted through the dichroic mirror 14 is condensed on the light-receiving surface of each photoelectric conversion element 21 that constitutes the line sensor 20 described later. Second selfoc lens array 16 and second selfoc lens array 16
Excitation light cut filter 17, which cuts off the laser light L reflected on the surface of the sheet 50 and transmits the stimulated emission light M, which is slightly mixed with the stimulated emission light M transmitted through
By reading the signals output from the line sensor 20 in which a large number of photoelectric conversion elements 21 for receiving and photoelectrically converting the stimulated emission light M transmitted through 17 are arranged, and the photoelectric conversion elements 21 constituting the line sensor 20 are read. This is a configuration including image information reading means 30 for outputting to an image processing device or the like.

The first SELFOC lens array 15 acts on the dichroic mirror 14 so that the emission region of the stimulated emission light M on the sheet 50 becomes an image surface for forming an image with a size of 1: 1. The second SELFOC lens array 16 is a dichroic mirror on the light receiving surface of the photoelectric conversion element 21.
The function of making the image of the stimulated emission light M on 14 an image surface on which a size of 1: 1 is formed.

The optical system 12 composed of a collimator lens and a toric lens expands the laser light L from the BLD 11 onto the dichroic mirror 14 to a desired irradiation area.

More specifically, as shown in FIG. 2, a large number of line sensors 20 are arranged along the arrow X direction (for example, 1000 or more).
Of photoelectric conversion elements 21 are arranged. Also,
Many of these photoelectric conversion elements that make up the line sensor 20.
Each of the 21 has a light receiving surface having a size of about 100 μm in length × 100 μm in width. This size is the stimulated emission light M emitted from a portion of the surface of the sheet 50 having a size of about 100 μm in length × 100 μm in width. Is the size of receiving light. As the photoelectric conversion element 21, specifically, an amorphous silicon sensor, a CCD sensor, a MOS image sensor, or the like can be applied.

Next, the operation of the radiation image information reading apparatus of this embodiment will be described.

First, the scanning belt 40 moves in the direction of the arrow Y, so that the sheet 50 on which the radiation image information is accumulated and recorded, which is placed on the scanning belt 40, is conveyed in the direction of the arrow Y. The transport speed of the sheet 50 at this time is equal to the moving speed of the belt 40, and the moving speed of the belt 40 is input to the adding means 31.

On the other hand, the BLD 11 emits a linear laser beam L having a line width of about 100 μm substantially parallel to the surface of the sheet 50. The laser beam L is provided on the optical path of the collimator lens and toric. The beam is made into a parallel beam by the optical system 12 including a lens, is reflected by the dichroic mirror 14 and advances in a direction in which it is incident perpendicularly to the surface of the sheet 50.
A linear shape extending in the direction of the arrow X above 50 (line width d _L approximately 100
.mu.m) (see FIG. 3 (1)).

Since the linear laser light L incident on the sheet 50 is coherent light, it has a high directivity as compared with the fluorescence emitted from the fluorescent lamp or the light emitted from the LED array, so that the degree of focusing is high. It is high and the excitation energy is larger than those of fluorescence and the like. Therefore, it is possible to sufficiently excite the stimulable phosphor in the condensing region (line width d _{L of about} 100 μm) of the sheet 50, and as a result, the accumulated and recorded radiation is emitted from the stimulable phosphor in the converging region. The stimulated emission light M having a high emission intensity is emitted according to the image information.

The stimulated emission light M emitted from the sheet 50 is collimated by the first SELFOC lens 15, passes through the dichroic mirror 14, and the second SELFOC lens array 16 constitutes the line sensor 20. The light is condensed on the light receiving surface of each photoelectric conversion element 21. At this time, the excitation light cut filter 17 cuts the laser light L reflected on the surface of the sheet 50, which is slightly mixed in the stimulated emission light M transmitted through the second SELFOC lens array 16.

The stimulated emission light M which has passed through the filter 17
Is a large number of photoelectric conversion elements 21 constituting the line sensor 20.
Is received by and is converted into each image signal Q by photoelectric conversion. These image signals Q obtained by photoelectric conversion are input to the image information reading means 30, are associated with the position of the sheet 50 corresponding to the displacement amount of the scanning belt 40, and are output to the image processing device or the like.

Since the image signal Q thus obtained is based on the stimulated emission light M excited by the laser light L having high excitation energy, it is emitted from the fluorescent light emitted from the fluorescent lamp or the LED array. An image with a higher S / N can be obtained as compared with an image signal based on stimulated emission light excited by light.

The laser light L emitted from the BLD 11
Monitor means 60 (see FIG. 1) for monitoring the light amount of BLD11, and BLD modulating means for modulating the BLD11 so that the power of the BLD11 becomes constant based on the monitoring result by the monitor means 60.
When the light amount fluctuation of the emitted laser light L from the BLD 11 is detected by the monitor means 60, BL
The BLD 11 may be modulated by the D modulator 70 so that the light amount of the laser light L becomes constant.

FIG. 3 is a diagram showing a second embodiment of the radiation image information reading apparatus of the present invention, and FIG. 4 is a diagram showing the detailed construction of the line sensor 20 of the reading apparatus shown in FIG.

The illustrated radiation image information reading apparatus is a sheet
The scanning belt 40 on which 50 is mounted and conveyed in the direction of the arrow Y, the linear laser light L having a line width of about 100 μm is emitted substantially parallel to the surface of the sheet 50, and the linear laser light L emitted from the BLD 11 is emitted. An optical system 12 composed of a combination of a collimator lens for condensing and a toric lens for expanding a beam in only one direction, which is arranged at an angle of 45 degrees with respect to the surface of the sheet 50, reflects laser light L, and is described below. The dichroic mirror 14 set to transmit the emitted light M, and the linear laser light L reflected by the dichroic mirror 14.
Is condensed on a sheet 50 in a linear shape (line width of about 100 μm) extending along the arrow X direction, and the linear laser light L is condensed and emitted from the sheet 50. The first SELFOC lens array 15 that makes the stimulated emission light M corresponding to information into a parallel luminous flux, and the stimulated emission light M that has been made into a parallel luminous flux by the first SELFOC lens array 15 and has passed through the dichroic mirror 14. The second SELFOC lens array 16 and the second SELFOC lens array 16 for condensing the light on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20 described later.
Stimulated emission light M transmitted through the SELFOC lens array 16 of
Laser light L reflected on the surface of the sheet 50, which is slightly mixed in the
Line sensor in which a large number of photoelectric conversion elements 21 are arranged to cut off the light and to transmit the stimulated emission light M to transmit the excitation light cut filter 17, and to receive and photoelectrically convert the stimulated emission light M transmitted through the excitation light cut filter 17. 20 and the signal output from each photoelectric conversion element 21 that constitutes the line sensor 20,
It has an addition means 31 for performing addition processing in association with 50 parts,
This is a configuration including the image information reading unit 30 that outputs the image signal subjected to the addition processing.

The first SELFOC lens array 15 acts on the dichroic mirror 14 so that the emission area of the stimulated emission light M on the sheet 50 becomes an image surface for forming an image with a size of 1: 1. The second SELFOC lens array 16 is a dichroic mirror on the light receiving surface of the photoelectric conversion element 21.
The function of making the image of the stimulated emission light M on 14 an image surface on which a size of 1: 1 is formed.

The optical system 12 including a collimator lens and a toric lens expands the laser light L from the BLD 11 onto the dichroic mirror 14 to a desired irradiation area.

More specifically, as shown in FIG. 4, the number of line sensors 20 is large (eg, 1000 or more) along the arrow X direction.
The photoelectric conversion elements 21 are arranged and three rows of the photoelectric conversion elements 21 extending in the arrow X direction are continuously arranged in the sheet conveying direction (arrow Y direction). In addition, each of the large number of photoelectric conversion elements 21 constituting the line sensor 20 has a light receiving surface having a size of about 100 μm in length × 100 μm in width, and this size is 100 μm in length × width in the surface of the sheet 50. This is a size for receiving the stimulated emission light M emitted from a portion having a size of about 100 μm. As the photoelectric conversion element 21, specifically, an amorphous silicon sensor, a CCD sensor, a MOS image sensor, or the like can be applied.

As addition processing by the addition means 31, simple addition, weighted addition, etc. can be applied, and in place of the addition means 31, arithmetic processing means for performing other arithmetic processing may be applied.

Next, the operation of the radiation image information reading apparatus of this embodiment will be described.

First, when the scanning belt 40 moves in the arrow Y direction, the sheet 50 on which the radiation image information is accumulated and recorded, which is placed on the scanning belt 40, is conveyed in the arrow Y direction. The transport speed of the sheet 50 at this time is equal to the moving speed of the belt 40, and the moving speed of the belt 40 is input to the adding means 31.

On the other hand, the BLD 11 emits a linear laser beam L having a line width of about 100 μm substantially parallel to the surface of the sheet 50. The laser beam L is provided on the optical path of the collimator lens and toric. The beam is made into a parallel beam by the optical system 12 including a lens, is reflected by the dichroic mirror 14 and advances in a direction in which it is incident perpendicularly to the surface of the sheet 50.
A linear shape extending in the direction of the arrow X above 50 (line width d _L approximately 100
.mu.m) (see FIG. 5 (1)).

Since the linear laser light L incident on the sheet 50 is coherent light, it has a high directivity as compared with the fluorescence emitted from the fluorescent lamp or the light emitted from the LED array, so that the degree of focusing is high. It is high and the excitation energy is larger than those of fluorescence and the like. Therefore, it is possible to sufficiently excite the stimulable phosphor in the condensing region (line width d _{L of about} 100 μm) of the sheet 50, and as a result, the accumulated and recorded radiation is emitted from the stimulable phosphor in the converging region. The stimulated emission light M having a high emission intensity is emitted according to the image information.

The linear laser light L incident on the sheet 50 is
The stimulable phosphor in the light collection area (line width d _L approximately 100 μm) is excited, and the light enters the sheet 50 from the light collection area and diffuses into the vicinity of the light collection area. Width d _M )
The stimulable fluorescent substance of P. As a result, stimulated emission light M having an intensity corresponding to the radiation image information stored and recorded is emitted from the light condensing region of the sheet 50 and its vicinity (line width d _M ) (see (2) in the same figure). The intensity distribution in the line width direction is as shown in FIG.

The stimulated emission light M emitted from the portion having the line width d _M of the sheet 50 is made into a parallel light flux by the first SELFOC lens 15, passes through the dichroic mirror 14, and is transmitted through the second SELFOC lens array 16 Thus, the light is condensed on the light receiving surface of each photoelectric conversion element 21 that constitutes the line sensor 20. At this time, the excitation light cut filter 17 cuts the laser light L reflected on the surface of the sheet 50, which is slightly mixed in the stimulated emission light M transmitted through the second SELFOC lens array 16.

[0054] Here, on the light receiving surface of the line sensor 20, the relationship between the distribution of the size and emitted light M of the photoelectric conversion element 21, as shown in FIG. 4, beam width d _M of the surface of the sheet 50 is , Photoelectric conversion elements 21 for three columns in the arrow Y direction
It is supposed to correspond to the width (width approximately 300 μm).

The line sensor 20 photoelectrically converts the stimulated emission light M received by each photoelectric conversion element 21, and each signal Q obtained by photoelectric conversion is input to the adding means 31.

The adding means 31 accumulates and stores the signals Q from the corresponding photoelectric conversion elements 21 in the memory area provided corresponding to each part of the sheet 50 based on the moving speed of the scanning belt 40. Let

This operation will be described in detail below with reference to FIGS. 6 and 7. In order to simplify the explanation in this embodiment, the line width d _M of the emitted light M on the light receiving surface of the line width of the emitted light M of the sheet 50 on the surface d _M and the line sensor 20 The optical system arranged between the sheet 50 and the line sensor 20 was set so that
Line width d _M of stimulated emission light M on the surface and line sensor
Not have a line width d _M of the emitted light M to be limited to necessarily match on the light receiving surface of 20, the photoelectric conversion elements constituting the line sensor 20 according to the corresponding relationship between the two 21 The size and the number of columns in the line width direction may be set.

First, as shown in FIG. 6A, the sheet 50
In the state where the fluorescent light L is focused on the front end portion S1 of the sheet conveyance direction (direction of the arrow Y), the sheet spreads due to the spread of the laser light L.
The stimulated emission light M as shown by the emission distribution curve in the figure is emitted not only from the tip end portion S1 of 50 but also from the vicinity region S2 thereof as described above. The quantity of the stimulated emission light M generated from the portion S1 of the sheet 50 is Q2, and the quantity of the stimulated emission light M of this quantity Q2 is the photoelectric conversion element array 20 corresponding to the portion S1 of the sheet 50.
The quantity of the stimulated emission light M received from the photoelectric conversion element 21 of B (see FIG. 4) and generated from the portion S2 of the sheet 50 is Q3, and the stimulated emission light M of this light quantity Q3 is the portion of the sheet 50. The light is received by the photoelectric conversion element 21 of the photoelectric conversion element array 20C corresponding to S2.

The photoelectric conversion element 21 (20B column) photoelectrically converts the received stimulated emission light M having the light quantity Q2 into the charge Q'2, and transfers the charge Q'2 to the adding means 31. The addition means 31 is a photoelectric conversion element 21.
The charge Q′2 transferred from (column 20B) is applied to the scanning belt 40.
It is stored in the memory corresponding to the part S1 of the sheet 50 on the basis of the scanning speed (see FIG. 7). Similarly, the photoelectric conversion element 21 (20C column) photoelectrically converts the received stimulated emission light M having the light quantity Q3 into the charge Q'3, and transfers this to the adding means 31.
The adding means 31 stores the transferred charge Q′3 in the memory corresponding to the portion S2 of the sheet 50.

Next, the sheet 50 is conveyed, and as shown in FIG. 6 (2).
As shown in, in the state where the fluorescence L is condensed on the site S2 of the sheet 50, the sheet 50 is operated by the same action as described above.
The stimulated emission light M is generated from the portion S2 in the vicinity of the portion S2 as well as the neighboring portions S1 and S3, and the stimulated emission light M having the light amount Q4 from the portion S1, the light amount Q5 from the portion S2, and the light amount Q6 from the portion S3 is generated The stimulated emission light M is received by the corresponding photoelectric conversion elements 21 (20A row), 21 (20B row), 21 (20C row).

Each photoelectric conversion element 21 (20A column), 21 (20B)
The columns 21 and 20 (column 20C) convert the received stimulated emission light M into charges Q'4, Q'5 and Q'6, respectively, and transfer them to the adding means 31.

The adding means 31 includes photoelectric conversion elements (20A line),
The charges Q'4, Q'5, Q'6 transferred from 21 (20B row) and 21 (20C row), respectively, are transferred to the parts S1, S2, S3 of the sheet 50 based on the scanning speed of the scanning belt 40. Add to the corresponding memory and store.

Thereafter, in the state where the sheet 50 is conveyed and the fluorescence L is condensed on the part S3 of the sheet 50 as shown in FIG. 6C, the photoelectric conversion elements 21 (20A row), 21 (20B) are arranged.
Column), 21 (20C column) respectively transferred charge Q '
7, Q'8 and Q'9 are also added and stored in the memories corresponding to the portions S2, S3 and S4 of the sheet 50 by the same action.

By repeating the same operation as described above for each conveyance position of the sheet 50, as shown in FIG. 7, the memory of the adding means 31 corresponding to each part of the sheet 50 is conveyed to the conveyance position of the sheet 50. The total sum of the stimulated emission light M received for each is stored.

Then, the signal stored in this memory is output from the image information reading means 30 to an external image processing device or the like and used for reproducing a diagnostic image.

As described above, according to the radiation image information reading apparatus of the present embodiment, the obtained image signal Q is based on the stimulated emission light M excited by the laser light L having high excitation energy. Fluorescence emitted from fluorescent lamps and LEDs
An image with a higher S / N can be obtained as compared with an image signal based on stimulated emission light excited by the light emitted from the array. Further, the line width of the emitted light d _M less light receiving width than (the line width of the light receiving surface of the photoelectric conversion element) d _P (<
By using the photoelectric conversion element of d _M ), the line sensor as a whole can receive light over substantially the entire line width of the stimulated emission light while ensuring a desired resolution, and thus the light receiving efficiency can be improved. it can. Then, the adding means adds the output of each photoelectric conversion element at each position where the sheet is moved by the scanning belt to each sheet portion, thereby increasing the light collection efficiency for each portion of the sheet. You can

The radiation image information reading apparatus of the present invention is not limited to the above-described embodiment, but a broad area laser, a condensing optical system between the broad area laser and the sheet, and a light collecting optical system between the sheet and the line sensor. Various known configurations can be adopted as the optical system, the line sensor, or the calculation means. Further, a configuration further including an image processing device that performs various kinds of signal processing on a signal output from the image information reading means, and an erasing means that appropriately emits the radiation energy still remaining on the excited sheet are further provided. It is also possible to adopt the configuration provided.

In the line sensor 20 of this embodiment, as shown in FIG.
In both of the length direction (major axis direction) and the direction orthogonal to the major axis direction (minor axis direction), the matrix is arranged in a straight line. The line sensor used in the radiation image information reading device is not limited to that of the embodiment, and as shown in FIG. 8 (1), the line sensor may be 1 in the long axis direction (arrow X direction).
The lines are arranged in a straight line, but the short axis direction (arrow Y direction) is arranged in a zigzag shape, or 1 in the short axis direction as shown in FIG.
They may be arranged in a straight line, but arranged in a zigzag arrangement in the long axis direction.

Furthermore, the radiation image information reading apparatus of the above-mentioned embodiment adopts a configuration in which the optical path of the laser light L and the optical path of the stimulated emission light M partially overlap.
Although the apparatus is intended to be made more compact, the present invention is not limited to such a configuration. For example, as shown in FIG. 9, the optical path of the laser light L and the optical path of the stimulated emission light M do not overlap at all. Can also be applied.

That is, in the illustrated radiation image information reading apparatus, the scanning belt 40, the BLD11 emitting the linear laser light L at an angle of about 45 degrees with respect to the surface of the sheet 50, and the linear laser light L emitted from the BLD11. Is composed of a collimator lens for condensing light and a toric lens for expanding the beam only in one direction, and the optical system 12 for irradiating the surface of the sheet 50 with the linear laser light L, and the surface of the sheet 50 is inclined by about 45 degrees. Each photoelectric conversion element 21 having an optical axis that is substantially orthogonal to the direction of advance of the laser light L, and the stimulated emission light M emitted from the sheet 50 by the irradiation of the laser light L constitutes the line sensor 20 described later. SELFOC lens array 16 for condensing on the light receiving surface of EX, excitation light cut filter 17 for cutting laser light L mixed in stimulated emission light M incident on SELFOC lens array 16, excitation light cut Plurality of photoelectric conversion elements filter 17 by receiving the emitted light M having passed through the photoelectrically converts 21
Line sensor 20 with lined up, and line sensor
The signal output from each photoelectric conversion element 21 constituting 20
The configuration is such that it has an addition means 31 for performing addition processing corresponding to the parts of the sheet 50, and an image information reading means 30 for outputting this addition-processed image signal.

By using a stimulable phosphor sheet whose support is made of a material that transmits stimulated emission light, the BLD and the line sensor are placed on different surface sides of the sheet, as shown in FIG. It is also possible to employ a transmitted light condensing type configuration in which the stimulated emission light emitted from the surface opposite to the sheet surface on which the laser light is incident is received.

That is, in the illustrated radiation image information reading apparatus, the radiation image is not recorded on the front end portion and the rear end portion of the stimulable phosphor sheet 50 (the radiation image is not recorded on the front end portion and the rear end portion). Is not the region of interest) and conveys the sheet in the direction of the arrow Y, and the linear laser light L is emitted from BLD11 and BLD11 that emit in a direction substantially orthogonal to the surface of the sheet 50. The optical system 12 for irradiating the surface of the sheet 50 with the linear laser light L and the surface of the sheet 50, which is composed of a combination of a collimator lens for condensing the linear laser light L and a toric lens for expanding the beam in only one direction. The photostimulable emission light M'which has an optical axis substantially orthogonal to and is emitted from the back surface of the sheet 50 (the surface opposite to the incident surface of the laser light L) by the irradiation of the laser light L.
Each photoelectric conversion element 21 constituting the line sensor 20 described later.
SELFOC lens array 16 for condensing on the light-receiving surface of EX, and an excitation light cut filter for cutting the laser light L mixed in the stimulated emission light M ′ incident on the SELFOC lens array 16.
17, a line sensor 20 in which a large number of photoelectric conversion elements 21 for receiving and photoelectrically converting the stimulated emission light M ′ transmitted through the excitation light cut filter 17, and a line sensor 20
Comprising a signal output from each photoelectric conversion element 21 constituting the, the addition means 31 for performing addition processing corresponding to the site of the sheet 50, the image information reading means 30 for outputting the image signal subjected to the addition processing It has a different structure.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a radiation image information reading apparatus of the present invention.

FIG. 2 is a diagram showing details of a line sensor of the radiation image information reading apparatus shown in FIG.

FIG. 3 is a configuration diagram (1) showing another embodiment of the radiation image information reading apparatus of the invention.

4 is a diagram showing details of a line sensor of the radiation image information reading apparatus shown in FIG.

FIG. 5 is a diagram showing the relationship between the beam width of laser light and the beam width of stimulated emission light.

FIG. 6 is a diagram for explaining the operation of the radiation image information reading apparatus of the embodiment shown in FIG.

FIG. 7 is a conceptual diagram showing a memory of an addition unit corresponding to each part of a sheet.

FIG. 8 is a diagram showing another arrangement state of photoelectric conversion elements which form a line sensor.

FIG. 9 is a configuration diagram (2) showing another embodiment of the radiation image information reading apparatus of the invention.

FIG. 10 is a configuration diagram (3) showing another embodiment of the radiation image information reading apparatus of the invention.

[Explanation of symbols]

11 Broad area semiconductor laser (BLD) 12 Optical system consisting of collimator lens and toric lens 14 Dichroic mirror 15, 16 SELFOC lens array 17 Excitation light cut filter 20 Line sensor 21 Photoelectric conversion element 30 Image information reading means 31 Addition means (calculation) Means 40 scanning belt 50 stimulable phosphor sheet L laser light M stimulated emission light

Continuation of the front page (56) Reference JP-A-7-64218 (JP, A) JP-A-1-287527 (JP, A) JP-A 61-63152 (JP, A) JP-A 64-101540 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 42/02 H04N 1/04

Claims (2)

(57) [Claims] 1. A line light source for linearly irradiating a part of a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and a linearly irradiated portion of the sheet or this irradiated portion. For photoelectric conversion by receiving stimulated emission light emitted from the portion on the back surface side of the sheet, a line sensor in which a large number of photoelectric conversion elements are arranged, the line light source and the line sensor in the sheet Relative to the above, a scanning means for moving in a direction different from the linear length direction and a reading means for sequentially reading the output of each photoelectric conversion element forming the line sensor according to the movement are provided. in the radiation image information reading apparatus, said line light source, Ri Oh broad area laser which emits the excitation light into a linear shape, exits from the broad area laser
Longitudinal direction of the irradiation area on the sheet by the emitted excitation light
The length of the sheet is longer than one side of the sheet or
Hitoshidea Rukoto radiation image information reading apparatus according to claim. 2. The line sensor has a plurality of photoelectric conversion elements arranged in the linear lengthwise direction and in a direction orthogonal to the linear lengthwise direction, and the reading means is moved by the scanning means. 7. The apparatus further comprises arithmetic means for arithmetically processing the output of each of the plurality of photoelectric conversion elements in the direction orthogonal to the length direction at each of the defined positions in association with the portion of the sheet. 1. The radiation image information reading device described in 1.