JP2000066316A - Reading device of radiation image information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve condensing efficiency of stimulated luminous light while maintaining desired resolution by detecting the stimulated luminous light emitted from a linear part of a sheet by using a line sensor having plural photoelectron conversion elements arranged. SOLUTION: Linear exciting light L entering a sheet 50 excites an accumulative phosphor in the area where light is condensed, while the light enters into the sheet 50 from the condensed region and diffuses to excite the accumulative phosphor near the condensed region. As a result, stimulated luminous light M is emitted with the intensity according to the radiation image information recorded and accumulated in the condensed region and near the region of the sheet. The stimulated luminous light M is accepted by each photoelectron conversion element 21 of the line sensor 20 and converted into electrons. The signals obtd. by photoelectron conversion are sent to an adding means 31. The adding means 31 accumulates and stores signals from the photoelectron conversion elements 21 in the respective memory region provided in the sheet 50 based on a transfer speed of a traveling belt 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a radiation image information reading apparatus, and more particularly to a radiation image information reading apparatus which reads stimulated emission light emitted from a stimulable phosphor sheet by a line sensor.

[0002]

2. Description of the Related Art When radiation is irradiated, a part of this radiation energy is accumulated, and thereafter, when irradiated with excitation light such as visible light or laser light, a stimulable phosphor that emits stimulated light in accordance with the accumulated radiation energy. (Photostimulable phosphor) is used to temporarily accumulate and record radiation image information of a subject such as a human body on a sheet-shaped stimulable phosphor sheet formed by laminating a stimulable phosphor on a support. Excitation light such as laser light is deflected and scanned for each pixel to generate stimulated emission light sequentially from each pixel, and the obtained stimulated emission light is photoelectrically sequentially read by photoelectric reading means to obtain an image signal. A radiation image recording / reproducing system that emits erasing light to the stimulable phosphor sheet after reading the image signal and emits radiation energy remaining on the sheet is widely used in practice.

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 the image signal after these processings is applied as a diagnostic visible image. Filmed 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 from which the residual radiant energy irradiated with the erasing light has been released can store and record radiation image information again, and can be used repeatedly.

Here, in the radiation image information reading apparatus used in the above-mentioned radiation image recording / reproducing system,
From the viewpoint of shortening the reading time of the stimulated emission light, downsizing of the device and cost reduction, a line light source that irradiates the sheet with the excitation light linearly as the excitation light source is used.
As the photoelectric reading means, 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 the excitation light by the line light source, and the line light source and the line sensor are used. Japanese Patent Application Laid-Open Nos. 60-111568 and 60-236354 disclose a configuration having a scanning means which moves in a direction substantially perpendicular to the length direction of the linear portion relative to the sheet. JP-A-1-10
No. 1540).

[0005]

FIG. 6 (1)
Assuming that the beam width (line width) of the stimulating light M emitted linearly from the sheet 50 (line extending in the direction penetrating the paper surface) from the sheet 50 is d _M , the emission intensity distribution in the line width direction is the same. FIGS. 2 and 3 show the photostimulated light M
Is collected by a line sensor (see FIG. 2B) in which the light receiving width d _P of each photoelectric conversion element is less than the line width d _M , the light collection efficiency is low, while the light receiving width of each photoelectric conversion element is low. d _P is condensed by if the light collection efficiency by the line sensor to substantially coincide with the line width d _M (see FIG. 3) is improved, there is a problem that resolution for one pixel size is large is decreased ( The same applies to a rectangular shape having a length in the line width direction longer than the length in the line extension direction.)

The emission intensity distribution of the stimulated emission light M is as shown in FIGS. 2 and 3 because the line width of the excitation light L is widened before the light enters the sheet 50. FIG.
As shown in (1) and (2), the excitation light L having a line width d _L (<d _M ) incident on the inside of the sheet 50 is scattered inside the sheet 50, and the stimulating light emitted inside the sheet 50 is emitted. Before the emission light M exits from the surface of the sheet 50, the sheet
This is due to scattering inside 50.

The present invention has been made in view of the above circumstances, and provides a radiation image information reading / recording apparatus capable of improving the light collection efficiency of stimulating light while securing a desired resolution. The purpose is to do so.

[0008]

A radiation image information reading apparatus according to the present invention detects stimulated emission light emitted from a linear portion of a sheet by a line sensor provided with a plurality of photoelectric conversion elements in both the vertical and horizontal directions. Then, the output of each photoelectric conversion element for each scanning position is subjected to arithmetic processing in correspondence with the portion of the stimulable phosphor sheet, thereby improving the light collection efficiency.

That is, a radiation image information reading apparatus according to the present invention comprises 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 linear irradiance for the sheet. Receiving the stimulated emission light emitted from the irradiated portion or the portion on the back surface side of the sheet corresponding to the irradiated portion, and performing photoelectric conversion, the length direction (long axis direction) of the portion and a direction orthogonal thereto. A line sensor in which a plurality of photoelectric conversion elements are disposed in a direction (short axis direction), and the line light source and the line sensor are moved relative to the sheet in a direction different from the length direction. Scanning means for reading, and the output of the line sensor is sequentially read in accordance with the movement, and the output of each photoelectric conversion element at each position moved by the scanning means is compared with the portion of the sheet. Is characterized in that a reading means has a calculating means for calculating process by.

As the line sensor, an amorphous silicon sensor, a CCD sensor, a CCD with a back illuminator, a MOS image sensor, and the like can be applied. In this case, as the line sensor, a plurality of sensor chips (CCD chip, MOS image sensor chip, etc.)
May be arranged in a linear length direction in a linear or staggered manner. Each of the sensor chips has a plurality of photoelectric conversion elements in the vertical and horizontal directions, respectively.
They may be arranged in a matrix or zigzag (staggered).

As the line light source, a fluorescent lamp, a cold cathode fluorescent lamp, an LED array or the like can be applied. In addition, the line light source is not limited to a light source itself having a linear shape like the above-described fluorescent lamp or the like, and may be a light source in which emitted excitation light is linear, and includes a broad area laser and the like. . The excitation light emitted from the line light source is
The light may be emitted continuously or may be emitted in a pulse shape in which emission and stop are repeated. However, from the viewpoint of reducing noise, high-output pulse light is desirable. .

It is desirable that the length of the irradiation area on the stimulable phosphor sheet by the excitation light emitted from the line light source in the major axis direction is longer than or equal to one side of the stimulable phosphor sheet. In this case, the excitation light may be emitted while being inclined with respect to the side of the sheet.

Here, in order to improve the degree of condensing the excitation light emitted from the light source on the sheet, a cylindrical lens, a slit, a selfoc lens (rod lens) array, a fluorescent light guide sheet, an optical fiber bundle, etc. Alternatively, it is desirable to dispose a combination thereof between the light source and the sheet. When the optimal secondary excitation wavelength of the stimulable phosphor sheet is around 600 nm, the fluorescent light guide sheet may be one in which the activator of the phosphor is Eu3 + (emission center) and is a glass or polymer medium. desirable.

The width of the excitation light emitted from the light source on the sheet is preferably 10 to 4000 μm.

Further, in order to increase the degree of condensing the stimulated emission light emitted from each portion of the sheet on the line sensor, an image forming system in which the object surface and the image surface correspond one-to-one. A lens array such as a selfoc lens (registered trademark; hereinafter abbreviated), 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 disposed between the sheet and the line sensor. It is desirable to set up.

Furthermore, between the sheet and the line sensor,
It is preferable to provide an excitation light cut filter (a sharp cut filter, a band pass filter) that transmits the stimulating light but does not transmit the excitation light to prevent the excitation light from entering the line sensor.

The size of the light receiving surface of each of the many photoelectric conversion elements constituting the line sensor is determined by the amount of stimulated emission light emitted from the sheet irradiated with the above-described light beam width by the excitation light.
It is set smaller than the light beam width on the light receiving surface of the line sensor, and a plurality of photoelectric conversion elements are arranged in the length direction (long axis direction) and the light beam width direction (short axis direction) of the light beam, respectively. The length of the entire sensor is set to be substantially equal to or longer than the light beam length, and is set to be substantially equal to the light beam width. The plurality of photoelectric conversion elements are not limited to a matrix arrangement in which the photoelectric conversion elements are arranged in a straight line in any of the major axis direction and the minor axis direction. They are arranged in a zigzag arrangement in the short axis direction, or in a zigzag arrangement in the short axis direction, but in a zigzag arrangement in the long axis direction, or in a zigzag arrangement in both axial directions. There may be.

In a configuration in which the number of photoelectric conversion elements is increased so as to be affected by the transfer rate, a memory element corresponding to each photoelectric conversion element is provided, and the charge accumulated in each photoelectric conversion element is temporarily stored. A configuration may be employed in which the charge is stored in each memory element and the charge is read out from each memory element during the next charge storage period, thereby avoiding a reduction in the charge storage time due to an 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 one side of the sheet or equivalent on the light receiving surface.

The direction in which the line light source and the line sensor are moved relative to the sheet by the scanning means (the direction different from the length direction) is a direction substantially orthogonal to the length direction. That is, it is desirable that the direction is the short axis direction. However, the direction is not limited to this direction. For example, as described above, in a configuration in which the line light source and the line sensor are longer than one side of the sheet, the line extends over substantially the entire surface of the sheet. Within a range in which the excitation light can be evenly irradiated, the light source and the line sensor may be moved in an oblique direction deviating from a direction substantially perpendicular to the length direction, or may be moved in a zigzag shape, for example. The movement may be performed by changing the direction.

The line light source and the line sensor may be arranged on the same side of the sheet, or may be arranged separately on the opposite sides. However, if you ’re using a separate configuration,
It is necessary to make the support of the sheet transparent to the stimulating light so that the stimulating light is transmitted to the surface of the sheet opposite to the surface on which the excitation light is incident.

The arithmetic processing is, specifically, a simple addition processing,
Weighted addition processing or other various arithmetic processing can be applied. Therefore, in the case of performing a simple addition process or a weighted addition process, an addition unit may be applied as a calculation unit.

[0023]

According to the radiation image information reading apparatus of the present invention, the line sensor has a plurality of photoelectric conversion elements in the length direction of the linear stimulating light emitted from the sheet and in the direction perpendicular to the length. Even if the light receiving width of each photoelectric conversion element is shorter than the line width of the photostimulated emission light (the line width on the light receiving surface of the photoelectric conversion element), the photoluminescence emission light is generated as a whole line sensor. Since the light can be received over substantially the entire width of the line, the light receiving efficiency can be improved. The output of each photoelectric conversion element at each position where the sheet or the sensor is moved by the scanning unit is calculated by the arithmetic unit by performing an arithmetic process such as an addition process in correspondence with the site of the sheet. Can improve the light collection efficiency. 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 a desired resolution can be secured.

If the line sensor is manufactured by arranging a plurality of sensor chips, the manufacture of the line sensor is facilitated, the production yield is improved, and the cost can be reduced. In particular, if the sensor chips are arranged in a zigzag shape (zigzag pattern), an empty area in which the sensor chip is not arranged can be provided. In this empty area, an electric circuit such as a circuit for correcting a pixel shift and other electric circuits can be provided. This is convenient because it is possible to arrange the items.

It should be noted that the radiation image information reading apparatus of the present invention employs a configuration using a line sensor as a photoelectric reading means, in comparison with a conventional radiation image information reading apparatus using a photoelectric reading means other than a line sensor. Accordingly, it is also possible to reduce the reading time of the stimulated emission light, to reduce the size of the apparatus, and to reduce the cost by reducing the mechanical scanning optical parts and the like.

[0026]

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

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

The illustrated radiation image information reading apparatus has a stimulable phosphor sheet (hereinafter, referred to as a radiation image information sheet) on 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 arrow Y, a linear secondary excitation light (hereinafter, referred to as a line excitation) having a line width of about 100 μm.
A broad area laser (hereinafter, referred to as BLD) 11, BL which emits an excitation light (hereinafter simply referred to as L) substantially parallel to the surface of the sheet 50.
An optical system 12 comprising a combination of a collimator lens for condensing the linear excitation light L emitted from D11 and a toric lens for expanding the beam only in one direction, which is arranged at an angle of 45 degrees with respect to the surface of the sheet 50. Further, a dichroic mirror 14 set so as to reflect the excitation light L and transmit a stimulated emission light M described later, and a linear excitation light L reflected by the dichroic mirror 14 on the sheet 50 in the direction of arrow X. The light is condensed into a linear shape (line width of about 100 μm) extending along the line, and the stimulated emission light M according to the accumulated and recorded radiation image information, which is emitted from the sheet 50 by condensing the linear excitation light L, A gradient index lens array (a lens in which a number of gradient index lenses are arrayed, hereinafter referred to as a first selfoc lens array) 15 for forming a parallel light beam; A second selfoc lens array 16 for condensing the stimulated emission light M, which has been converted into a parallel light beam by the lens array 15 and has passed through the dichroic mirror 14, on a light receiving surface of each photoelectric conversion element 21 constituting a line sensor 20 described later; An excitation light cut filter 17 that cuts the excitation light L reflected on the surface of the sheet 50 and that transmits the excitation light M, which is slightly mixed with the stimulable emission light M transmitted through the second selfoc lens array 16, A line sensor 20 in which a large number of photoelectric conversion elements 21 are arranged to receive the photostimulated light M transmitted through the light cut filter 17 and perform photoelectric conversion, and signals output from the respective photoelectric conversion elements 21 constituting the line sensor 20 Means for performing the addition process in correspondence with the parts of the sheet 50
31 and an image information reading means 30 for outputting the added image signal.

The first selfoc lens array 15 has an effect on the dichroic mirror 14 of setting an emission area of the photostimulated light M on the sheet 50 as an image plane for forming a one-to-one image. The second selfoc lens array 16 has a dichroic mirror on the light receiving surface of the photoelectric conversion element 21.
The image of the stimulated emission light M on the image 14 is formed into an image plane on which the image is formed in a one-to-one size.

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

More specifically, as shown in FIG. 2, the line sensor 20 has a large number (for example, 1000 or more) of photoelectric conversion elements 21 arranged along the arrow X direction, and the photoelectric conversion elements 21 extending in the arrow X direction. The rows of the elements 21 are arranged in three rows in the conveying direction of the sheet 50 (the direction of the arrow Y). Each of these photoelectric conversion elements 21 constituting the line sensor 20 has a light receiving surface having a size of about 100 μm × 100 μm, and the size is 100 μm × width on the surface of the sheet 50. It is a size that receives the stimulated emission light M emitted from a portion having a size of about 100 μm. In addition,
Specifically, as the photoelectric conversion element 21, 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, by moving the scanning belt 40 in the direction of the arrow Y, the sheet 50 on which the radiation image information is stored and conveyed is conveyed in the direction of the arrow Y. At this time, the conveying speed of the sheet 50 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 excitation light L having a line width of about 100 μm substantially parallel to the surface of the sheet 50.
The excitation light L is converted into a parallel beam by an optical system 12 including a collimator lens and a toric lens provided on the optical path, is reflected by the dichroic mirror 14, and travels in a direction perpendicular to the surface of the sheet 50. A linear shape (line width d _L approximately 100 μm) extending along the arrow X direction on the sheet 50 by the first Selfoc lens 15
(See FIG. 3A).

The linear excitation light L incident on the sheet 50 excites the stimulable phosphor in the light condensing area (line width d _{L of about} 100 μm) and enters the sheet 50 from the light condensing area to be condensed. The light is diffused in the vicinity of the region, and the stimulable phosphor in the vicinity (line width d _M ) of the light collection region is also excited. As a result, stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information is emitted from the light condensing area of the sheet 50 and its vicinity (line width d _M ) (see FIG. 2B). The intensity distribution in the line width direction is as shown in FIG.

The stimulated emission light M emitted from the portion of the sheet 50 having the line width d _M is converted into a parallel light beam by the first selfoc lens 15, passes through the dichroic mirror 14, and passes through the second selfoc lens array 16. Accordingly, the light is condensed on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20. At this time, the excitation light L slightly reflected on the stimulated emission light M transmitted through the second selfoc lens array 16 and reflected on the surface of the sheet 50 is cut by the excitation light cut filter 17.

[0037] 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. 2, beam width d _M of the surface of the sheet 50 is , Photoelectric conversion elements 21 for three rows in the arrow Y direction
(Approximately 300 μm in width).

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

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

This operation will be described below in detail with reference to FIGS. 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 is set so that
Line width d _M of photostimulated 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 And the number of columns in the line width direction may be set.

First, as shown in FIG.
When the fluorescent light L is condensed on the leading end S1 of the sheet 50 in the conveying direction (the direction of the arrow Y), the spread of the excitation light L
The stimulating luminescence light M as shown in the luminescence distribution curve of FIG. The amount of the stimulating light M generated from the portion S1 of the sheet 50 is Q2, and the amount of the stimulating light M
Is a photoelectric conversion element row 20B corresponding to the portion S1 of the sheet 50.
(See FIG. 2)
The light quantity of the stimulating light M generated from the portion S2 of the sheet 50 is Q3, and the stimulating light M of the light amount Q3 is
The light is received by the photoelectric conversion elements 21 of the photoelectric conversion element row 20C corresponding to No. 2.

The photoelectric conversion element 21 (20B column) photoelectrically converts the received stimulating light M of the light quantity Q2 into a charge Q'2, and transfers this to the adding means 31. The adding means 31 is a photoelectric conversion element 21
The charge Q′2 transferred from the (20B column) is
Is stored in the memory corresponding to the portion S1 of the sheet 50 based on the scanning speed (see FIG. 5). Similarly, the photoelectric conversion element 21 (20C column) photoelectrically converts the stimulating light M of the received light quantity Q3 into a charge Q'3, and transfers this to the adding means 31.
The adding means 31 stores the transferred charge Q'3 in a memory corresponding to the portion S2 of the sheet 50.

Next, the sheet 50 is conveyed, and FIG.
As shown in the figure, in a state where the fluorescent light L is condensed on the portion S2 of the sheet 50, the sheet 50 is operated by the same operation as described above.
Stimulated luminescent light M is also generated from the neighboring portions S1 and S3 around the portion S2, and the stimulated luminescent light M is generated from the portion S1 as the light amount Q4, the portion S2 as the light amount Q5, and the portion S3 as the light amount Q6. The stimulated emission light M is received by the corresponding photoelectric conversion elements 21 (20A column), 21 (20B column), and 21 (20C column).

Each of the photoelectric conversion elements 21 (20A row), 21 (20B
Columns 21 and 21 (column 20C) convert the received photostimulated light M into charges Q'4, Q'5, Q'6 and transfer them to the adding means 31, respectively.

The adding means 31 is provided for each photoelectric conversion element (20A column),
The charges Q'4, Q'5, and Q'6 transferred from 21 (column 20B) and 21 (column 20C) are respectively transferred to portions S1, S2, and S3 of the sheet 50 based on the scanning speed of the scanning belt 40. It is added to the corresponding memory and stored.

Subsequently, in a state where the sheet 50 is conveyed and the fluorescent light L is condensed on the portion S3 of the sheet 50 as shown in FIG. 4C, each of the photoelectric conversion elements 21 (20A row) and 21 (20B
Column), 21 (20C column) transferred charges Q 'respectively.
7, Q'8 and Q'9 are added and stored in the memories corresponding to the portions S2, S3 and S4 of the sheet 50 by the same operation.

The same operation as described above is repeated for each transport position of the sheet 50, so that the memory corresponding to each part of the sheet 50 of the adding means 31 stores the transport position of the sheet 50 as shown in FIG. The total sum of the stimulated emission light M received for each is stored.

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

As described above, according to the radiation image information reading apparatus of this embodiment, the light receiving width d _P (<d _M ) shorter than the line width d _M of the stimulated emission light (line width on the light receiving surface of the photoelectric conversion element).
By using the photoelectric conversion element described above, the desired resolution can be ensured, and the entire line sensor can receive light over substantially the entire width of the stimulated emission light, so that the light receiving efficiency can be increased. Then, the addition means increases the light-collecting efficiency of each part of the sheet by adding the output of each photoelectric conversion element at each position where the sheet is moved by the scanning belt in correspondence with the part of the sheet. Can be.

The radiation image information reading apparatus of the present invention is not limited to the above-described embodiment, but includes a light source, a condensing optical system between the light source and the sheet, an optical system between the sheet and the line sensor, and a line. Various known structures can be employed as the sensor or the adding means. In addition, the image processing apparatus further includes an image processing device that performs various signal processing on signals output from the image information reading unit, and an erasing unit that appropriately emits radiation energy still remaining on the sheet whose excitation has been completed. An equipped configuration can also be adopted.

Further, as shown in FIG. 2, the line sensor 20 in the present embodiment
In both the length direction (long axis direction) and the direction orthogonal to the long axis direction (short axis direction), a configuration is shown in which the elements are arranged in a matrix arranged in a straight line. The line sensor used in the radiation image information reading apparatus is not limited to the one in such an embodiment. As shown in FIG. 7A, one line sensor is used in the long axis direction (the direction of arrow X).
It is arranged in a straight line but arranged in a short axis direction (arrow Y direction) in a zigzag manner, or as shown in FIG.
They may be arranged in a straight line but arranged in a zigzag arrangement in the long axis direction.

Further, the radiation image information reading apparatus according to the above-described embodiment employs a configuration in which the optical path of the excitation light L and the optical path of the stimulating light M partially overlap, thereby further improving the apparatus. Although it is intended to be compact, it is not limited to such a configuration. For example, as shown in FIG.
A configuration in which the optical path of the excitation light L and the optical path of the stimulated emission light M do not overlap at all can be applied.

That is, the illustrated radiation image information reading apparatus includes a scanning belt 40, a BLD 11 that emits a linear excitation light L at an angle of approximately 45 degrees with respect to the surface of the sheet 50, and a linear excitation light L emitted from the BLD 11. An optical system 12 that irradiates a linear excitation light L onto the surface of the sheet 50, and is inclined by approximately 45 degrees with respect to the surface of the sheet 50, comprising a combination of a collimator lens for condensing the light and a toric lens that expands the beam in only one direction. Each of the photoelectric conversion elements constituting a line sensor 20 which has a light axis substantially perpendicular to the direction of travel of the excitation light L and emits stimulated emission light M emitted from the sheet 50 by irradiation of the excitation light L
Selfoc lens array 16, which focuses light on the light receiving surface of 21,
Excitation light cut filter 1 that cuts off excitation light L mixed with photostimulated light M incident on selfoc lens array 16
7, a line sensor 20 in which a large number of photoelectric conversion elements 21 that receive and stimulate photoelectric conversion of the photostimulated light M transmitted through the excitation light cut filter 17 and output from each photoelectric conversion element 21 constituting the line sensor 20 An addition means 31 is provided for adding the processed signals in correspondence with the parts of the sheet 50, and an image information reading means 30 for outputting the added image signal is provided.

The selfoc lens array 16 is arranged such that the photostimulated light M
Of the light emitting area is formed as an image plane on which an image is formed in a one-to-one size. The optical system 12 including a collimator lens and a toric lens transmits the excitation light L from the BLD 11 to a sheet 20.
Expand above to the desired irradiation area.

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

First, as the scanning belt 40 moves in the direction of the arrow Y, the sheet 50 on which the radiation image information is stored and recorded is conveyed in the direction of the arrow Y. At this time, the conveying speed of the sheet 50 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 excitation light L having a line width of approximately 100 μm in a direction inclined at an angle of approximately 45 degrees with respect to the surface of the sheet 50, and the excitation light L is projected on the optical path. The beam is converted into a parallel beam by an optical system 12 including a collimator lens and a toric lens provided, and is incident on the sheet 50 at an angle of about 45 degrees with respect to the surface of the sheet 50. At this time, the excitation light L irradiates a linear (line width d _L approximately 100 μm) region extending along the arrow X direction on the surface of the sheet 50.

The linear excitation light L incident on the sheet 50 excites the stimulable phosphor in the irradiation area (line width d _{L of about} 100 μm) and enters the sheet 50 from the irradiation area to the vicinity of the irradiation area. The stimulable phosphor in the vicinity of the irradiation area (line width d _M ) is also excited. As a result, from the irradiation area of the sheet 50 and the vicinity thereof (line width d _M ), stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information is emitted. The stimulated emission light M passes through the excitation light cut filter 17, cuts off the mixed excitation light L, enters the selfoc lens 16, and receives the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20. Is collected.

The operation after light reception by the line sensor 20 is the same as the operation of the radiation image information reading apparatus of the above-described embodiment, and the description thereof will be omitted.

As described above, according to the radiation image information reading apparatus of this embodiment, the light receiving width d _P (<the line width on the light receiving surface of the photoelectric conversion element) shorter than the line width d _M of the stimulated emission light (<
d _M ), the desired resolution can be ensured by using the photoelectric conversion element, and the entire line sensor can receive light over substantially the entire line width of stimulated emission light. it can. Then, the addition means increases the light-collecting efficiency of each part of the sheet by adding the output of each photoelectric conversion element at each position where the sheet is moved by the scanning belt in correspondence with the part of the sheet. Can be.

In the radiation image information reading apparatus of each of the above-described embodiments, both the light source of the excitation light and the line sensor are arranged on the same surface of the sheet, and the stimulated emission light emitted from the sheet surface on which the excitation light is incident. The radiation image information reading apparatus of the present invention is not limited to such a configuration, and the support is made of a material capable of transmitting photostimulated light. As shown in FIG. 9, by using the stimulable phosphor sheet formed by the method described above, the light source of the excitation light and the line sensor are arranged on different sides of the sheet, and the opposite side of the sheet surface on which the excitation light is incident. It is also possible to adopt a configuration of a transmitted light condensing type configured to receive stimulated emission light emitted from the side surface.

That is, in the illustrated radiation image information reading apparatus, the stimulable phosphor sheet 50 has a front end portion and a rear end portion (no radiation image is recorded at the front end portion and the rear end portion, or the radiation image is recorded at the front end and the rear end portion). Is also not a region of interest), a transport belt 40 'for transporting the sheet in the direction of arrow Y while supporting it, and BLD11 emitting linear excitation light L in a direction substantially perpendicular to the surface of the sheet 50, and exiting from the BLD11. An optical system 1 for irradiating the linear excitation light L to the surface of the sheet 50, comprising a combination of a collimator lens for condensing the linear excitation light L and a toric lens for expanding the beam only in one direction.
2. An excitation light L having an optical axis substantially orthogonal to the surface of the sheet 50,
The stimulated emission light M 'emitted from the back surface of the sheet 50 (the surface opposite to the incident surface of the excitation light L) by the irradiation of the light is irradiated onto the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20 described later. The selfoc lens array 16 to be condensed, the excitation light cut filter 17 for cutting the excitation light L mixed with the stimulated emission light M ′ incident on the selfoc lens array 16, and the stimulated emission light transmitted through the excitation light cut filter 17 A line sensor 20 in which a large number of photoelectric conversion elements 21 for receiving and receiving M ′ and performing photoelectric conversion are arranged, and signals output from the respective photoelectric conversion elements 21 constituting the line sensor 20 are made to correspond to portions of the sheet 50. It has an addition means 31 for performing addition processing, and is provided with an image information reading means 30 for outputting the image signal subjected to the addition processing.

The selfoc lens array 16 has a function of making the light-emitting area of the photostimulated light M 'on the back surface of the sheet 50 into an image plane for forming a one-to-one image on the light receiving surface of the photoelectric conversion element 21. Eggplant The optical system 12 composed of a collimator lens and a toric lens transmits the excitation light L from the BLD 11 to a sheet.
Expand the desired irradiation area on top of 20.

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

First, as the transport belt 40 'moves in the direction of arrow Y, the sheet 50 on which the radiation image information is stored and supported by the transport belt 40' is transported in the direction of arrow Y. The conveying speed of the sheet 50 at this time is the belt 40 '.
The movement speed of the belt 40 'is equal to the movement speed of the belt 40'.
Entered in 31.

On the other hand, the BLD 11 emits a linear excitation light L having a line width of about 100 μm in a direction substantially perpendicular to the surface of the sheet 50, and the excitation light L is provided on a collimator lens provided on the optical path. And optical system 12 consisting of toric lens
, And is incident on the sheet 50 substantially perpendicularly. At this time, the excitation light L irradiates a linear (line width d _L approximately 100 μm) region extending along the arrow X direction on the surface of the sheet 50.

The linear excitation light L incident on the sheet 50 excites the stimulable phosphor in the irradiation area (line width d _{L of about} 100 μm) and enters the sheet 50 from the irradiation area to the vicinity of the irradiation area. The stimulable phosphor in the vicinity of the irradiation area (line width d _M ) is also excited. As a result, from the irradiation area of the sheet 50 and the vicinity thereof (line width d _M ), stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information is emitted. At the same time, the stimulated emission light M 'transmitted through the transparent support of the sheet 50 is also emitted from the portion (line width d _M ') on the back surface side of the sheet 50.

The stimulated emission light M ′ emitted from the back side portion (line width d _M ′) of the sheet 50 passes through the excitation light cut filter 17, and after the mixed excitation light L is cut, the cell The light enters the Fock lens 16 and is focused on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20.

The operation after light reception by the line sensor 20 is the same as the operation of the radiation image information reading apparatus of the above-described embodiment, and the description thereof will be omitted.

As described above, also in the radiation image information reading apparatus of the present embodiment, the light receiving width d _P (<the line width on the light receiving surface of the photoelectric conversion element) shorter than the line width d _M ′ of the stimulated emission light on the back surface of the sheet (< By using the photoelectric conversion element of d _M ′), the desired resolution can be ensured, and the entire line sensor can receive light over substantially the entire line width of the stimulated emission light. Can be. Then, the addition means increases the light-collecting efficiency of each part of the sheet by adding the output of each photoelectric conversion element at each position where the sheet is moved by the scanning belt in correspondence with the part of the sheet. Can be.

It is to be noted that a configuration having arithmetic means in place of the adding means may be employed, and a weighted addition processing or other arithmetic processing may be applied in addition to the simple addition processing.

In any of the embodiments, the line sensor 20 used in the above-described radiation image information reading apparatus is manufactured by manufacturing a long line sensor having a length corresponding to the width of a sheet at a time. It is shown as
At present, it is not easy to manufacture a long line sensor as one member at a time, if not impossible, due to the current limitations in CCD manufacturing technology such as pixel shift. FIG. 10 shows one method of solving this technical problem, in which each uses a CCD chip smaller than the width of a sheet and connects a plurality of CCD chips in a linear length direction, that is, in a long axis direction. The arrangement in the direction of the arrow X indicates that the sheet width as a whole is configured to constitute one CCD line sensor. FIG. 10A shows a plurality of CCD chips 22 arranged in a straight line in the long axis direction (arrow X direction).
FIG. 10 (2) shows a plurality of CCD chips 22 arranged in a staggered manner so as not to have an overlapping portion in the long axis direction (arrow X direction), and FIG. 10 (3) shows a plurality of CCD chips 22.
Two CCD chips 22 in the major axis direction (arrow X direction)
22 shows a staggered arrangement in which a portion of 22 has an overlapping portion. In FIGS. 10 (2) and 10 (3), an electric circuit such as a circuit for correcting a pixel shift and other electric circuits are arranged in an empty area where the CCD chip 22 indicated by * is not arranged. Can be set up.

FIGS. 10 (4) to 10 (6) show each CCD chip 22.
2 shows an array configuration of the photoelectric conversion elements 21 which constitute the above. As is clear from the figure, the CCD chip 22 shown in FIG. 10D adopts the arrangement configuration of the line sensors 20 shown in FIG. The photoelectric conversion elements 21 are arranged along the X direction, and the arrow X
The rows of photoelectric conversion elements 21 extending in the direction are arranged in a plurality of rows (three rows in the figure) in the sheet conveying direction (the direction of the arrow Y) (not shown). CC shown in FIG. 10 (5)
The D chip 22 employs the arrangement configuration of the line sensors 20 shown in FIG. 7A, and is arranged linearly in the long axis direction (arrow X direction) and in the short axis direction (arrow Y direction). Are arranged in a zigzag pattern so that a plurality of rows are staggered as a whole. The CCD chip 22 shown in FIG. 10 (6) is a line sensor shown in FIG. 7 (2).
In this configuration, 20 arrays are used, and are arranged linearly in the short axis direction (arrow Y direction) and in the long axis direction (arrow X direction).
Direction), are arranged in a zigzag shape so that a plurality of rows are staggered as a whole. Photoelectric conversion element 21 in the long axis direction (direction of arrow X) of one CCD chip 22
Is preferably about 1/100 to 1/10 when, for example, the total number of photoelectric conversion elements 21 in the long axis direction (arrow X direction) of the line sensor 20 is about 1,000.

The CCD chip 22 forming the line sensor 20 shown in FIGS. 10 (1) to (3) can freely adopt any of the arrangements shown in FIGS. 10 (4) to 10 (6). . Further, the line sensor shown in FIGS.
Numerals 20 are arranged in the length direction (X direction) of the CCD chip 22. As shown in FIGS. 10 (7) to (9), the X direction of the line sensor 20 becomes the Y direction of the CCD chip 22. As described above, the line sensors 20 arranged in the X direction and the Y direction in the opposite direction, in other words, the line sensors 20 arranged in the width direction of the CCD chip 22.
It may be. 10 (1) to (3), (7) to (9)
In any case, it is needless to say that the respective effects of the line sensor 20 shown in FIGS. 2 and 7 can be obtained by the arrangement of the CCD chips 22.

As described above, by arranging a plurality of CCD chips in the long axis direction (the direction of the arrow X) so as to have a sheet width as a whole, one CCD line sensor is constituted. The sensor can be easily manufactured, the manufacturing yield can be improved, and the cost can be reduced.

Further, in correcting the pixel shift, since it becomes possible to take out the signal for each CCD chip as compared with the case where the whole is manufactured as one unit, the correction of the pixel shift becomes easy. In particular, as shown in FIG. 10 (3), when two CCD chips are arranged in a staggered manner so that a part of the CCD chips has an overlapping portion, pixel shift correction can be made easier by using data of the overlapping portion. become.

When arranging a plurality of CCD chips in the direction of the long axis (the direction of arrow X), it is preferable that no dead portion is formed at the joint portion. It is desirable to perform a correction process on the image data so as to correct the error, so that the seams are smoothly connected in the output image.

The method of arranging a plurality of CCD chips in the long axis direction (the direction of arrow X) so as to make the sheet width as a whole is not limited to the CCD line sensor, but may be an amorphous silicon sensor or the like. The present invention can be applied to a line sensor including a MOS image sensor.

Further, as a sheet used in the above-described radiation image information reading apparatus, two pieces of image information of the same subject having different radiation energy absorption characteristics are accumulated and recorded. A stimulable phosphor sheet for radiation energy subtraction, which can emit two stimulating luminescence lights from its front and back surfaces, and line sensors are separately arranged on both sides of the sheet, respectively. It is also possible to provide a device having a reading unit that performs subtraction processing on the image information read from both sides by corresponding the pixels on the front and back surfaces of the sheet, but in this case as well, each device is separately provided on both sides of the sheet. As described above, as described above, a plurality of sensor chips are arranged in a linear length direction to form a sheet as a whole. Can be used line sensor configured such that.

Further, as the stimulable phosphor sheet for radiation energy subtraction, for example, a sheet having a structure subdivided into a number of micro-chambers by an excitation light-reflective partition member extending in the thickness direction of the sheet, or the like. An anisotropic sheet can also be used.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing details of a line sensor of the radiation image information reading apparatus shown in FIG. 1;

FIG. 3 is a diagram showing the relationship between the beam width of excitation light and the beam width of stimulated emission light.

FIG. 4 is a view for explaining the operation of the radiation image information reading apparatus of the embodiment shown in FIG. 1;

FIG. 5 is a conceptual diagram showing a memory of an adding unit corresponding to each part of the sheet.

FIG. 6 is a diagram showing a relationship between the line width of stimulated emission light and a photoelectric conversion element constituting a conventional line sensor.

FIG. 7 is a diagram showing another arrangement state of the photoelectric conversion elements constituting the line sensor.

FIG. 8 is a configuration diagram showing another embodiment of the radiation image information reading apparatus of the present invention (part 1).

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

FIG. 10 is a diagram showing an arrangement state of a CCD chip constituting a line sensor and a photoelectric conversion element constituting the CCD chip;

[Explanation of symbols]

11 Broad area 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 22 CCD chip 30 Image information reading means 31 Addition means 40 scanning belt 50 stimulable phosphor sheet L excitation light M photostimulated light S1, S2,... Sheet part Q1, Q2,... Photostimulated light quantity Q'1, Q'2,.

Continued on the front page (72) Inventor Tetsu Arakawa Fuji Photo Film Co., Ltd. 798, Kaidai-cho, Ashigarashimo-gun, Kanagawa Prefecture

Claims (4)

[Claims] 1. A line light source 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 linearly irradiated part of the sheet or this irradiated part. A plurality of photoelectric conversion elements are arranged in the length direction of the portion and in the direction orthogonal to the portion, which receive the photostimulated light emitted from the portion on the back surface side of the sheet corresponding to A line sensor, scanning means for moving the line light source and the line sensor relative to the sheet in a direction different from the length direction, and sequentially reading the output of the line sensor in accordance with the movement; A reading unit having an arithmetic unit that performs an arithmetic process on an output of each of the photoelectric conversion elements at each position moved by the scanning unit in correspondence with a portion of the sheet. Radiation image information reading device. 2. The radiation image information reading apparatus according to claim 1, wherein the line sensor comprises a plurality of sensor chips arranged linearly in the linear length direction. 3. The radiation image information reading apparatus according to claim 1, wherein the line sensor comprises a plurality of sensor chips arranged in a staggered manner in the linear length direction. 4. The radiation image information according to claim 2, wherein each of the plurality of sensor chips has a plurality of the photoelectric conversion elements arranged in a vertical direction and a horizontal direction, respectively. Reader.