JP2002101269A - Radiation image information reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate focus deviation of a reading light and/or a stimulated phosphorescent light when reading a radiation image information on a detector panel. SOLUTION: A distance sensor 65 is provided at two points on both sides of an optical system 12 which measures a distance between a support stage 13 for a BLD 11 and the optical system 12 and a sheet 50 (a distance between the BLD 11, the optical system 12 and the sheet 50). The distance between the support stage 13 and the sheet 50 which is measured with the distance sensor 65 during scanning is transmitted to the control circuit of a DC motor 61. A position of the support stage 13 is adjusted by the DC motor 61 through a driver 62, so that the distance is equal to a preset optimum distance (in other words, the distance to always irradiate the stimulation light L to the surface of the sheet 50 from the BLD 11 with no focus deviation). The same focus control device is provided on both sides of a 'Selfoc (R)' lens array 16, and the focus of the stimulated phosphorescent light is so controlled that the stimulated phosphorescent light is always focused on a light receiving surface of a line sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radiation image information reading apparatus, and more particularly to a radiation image information reading apparatus using a linear light source as an excitation light source.

[0002]

2. Description of the Related Art Conventionally, solid-state radiation sensors have been widely used. For example, in medical radiation imaging, the radiation transmitted through the subject is irradiated on the radiation solid-state sensor, and a charge corresponding to the dose of the irradiated radiation is accumulated as a latent image charge in a power storage unit in the radiation solid-state sensor. While recording radiation image information as a charge latent image,
2. Description of the Related Art A solid-state radiation sensor that reads an image signal corresponding to a charge latent image from a power storage unit by an image reading unit is known. Various types of radiation solid-state sensors have been proposed.

For example, in terms of a charge reading process for obtaining an image signal corresponding to the amount of latent image charges stored in the power storage unit, there are a TFT reading method and an optical reading method.

Here, the TFT readout system scans and drives a TFT (thin film transistor) to convert the latent image charge stored in the power storage unit into a radiation image signal and outputs the radiation image signal. And converts the latent image charge stored in the power storage unit into an image signal by irradiating an electromagnetic wave for use (in general, visible light is used) and outputting the image signal (for example, Japanese Patent Application Laid-Open No. 2000-105297, And JP-A-10-271374).

Further, in the solid-state radiation sensor of the optical reading system, light from a point light source is used as scanning light to scan the entire area of the power storage unit of the radiation solid-state sensor and accumulate in each scanned part of the power storage unit. To convert a latent image charge into an image signal to obtain a radiation image, and to increase the reading speed, linearly irradiate light from a linear light source to the power storage unit of the radiation solid-state sensor as reading light, Scanning (sub-scanning) is performed in a direction (for example, a vertical direction) different from the length direction of the irradiated portion, and the latent image charges accumulated in each linearly irradiated portion of the power storage unit are converted into image signals. There are some that obtain a radiation image.

On the other hand, when radiation is irradiated, a part of the radiation energy is accumulated, and thereafter, when it is irradiated with excitation light such as visible light or laser light, an accumulated light which shows stimulated emission according to the accumulated radiation energy. By using a stimulable phosphor (stimulable phosphor), radiation image information of a subject such as a human body is once accumulated and recorded on a sheet-shaped stimulable phosphor sheet in which a stimulable phosphor is laminated on a support. In addition, the excitation light such as a laser beam is deflected and scanned for each pixel to sequentially generate stimulated emission light from each pixel, and the stimulated emission light is photoelectrically sequentially read by photoelectric reading means to obtain an image signal. On the other hand, a radiation image recording / reproducing system that irradiates an erasing light to the stimulable phosphor sheet after reading the image signal to emit radiation energy remaining on the sheet has been widely put into practical use (for example, HirakiAkira 55-12429 issue, same 55-116340 issue,
No. 56-104645).

The image signal obtained by the radiation image information reading apparatus using the solid-state radiation sensor and the stimulable phosphor sheet is subjected to image processing such as gradation processing and frequency processing suitable for observation and interpretation. The image signal that has been subjected to the above processing is recorded on a film as a diagnostic visible image, or displayed on a high-definition CRT and used for diagnosis by a doctor or the like.

On the other hand, when the stimulable phosphor sheet is irradiated with erasing light to release residual energy, the sheet can again store and record radiation image information and can be used repeatedly.

Here, in the radiation image information reading apparatus used in the above-mentioned radiation image recording and reproducing system,
From the viewpoint of shortening the reading time of the stimulated emission light, and reducing the size and cost of the apparatus, a line light source that irradiates the sheet with excitation light linearly is used as the excitation light source.
As the photoelectric reading means, a line sensor in which a large number of photoelectric conversion elements are arranged along a length direction (hereinafter, referred to as a main scanning direction) of a linear portion of a sheet irradiated with excitation light by a line light source is used. Scanning means for moving one of the line light source and the line sensor and the phosphor sheet relative to the other in a direction (sub-scanning direction) substantially orthogonal to the length direction of the linear portion. Japanese Patent Application Laid-Open Nos. 60-111568 and 60-23635
4, JP-A-1-101540).

[0010]

However, in the case of a radiation image information reading apparatus using a stimulable phosphor sheet, a condensing optical system for condensing the excitation light from the excitation light source linearly on the phosphor sheet. And a condensing optical system for condensing stimulated emission light from the phosphor sheet on the light-receiving surface of the line sensor. Since the aperture ratio of the optical optical system is increased, the depth of focus of each is narrow. Therefore, during scanning, a line light source (including a condensing optical system) and a line sensor (including a condensing optical system) and a fluorescent light may be generated due to play, flatness, thermal expansion, external vibration, and the like of the scanning feed mechanism. While the fluctuation of the distance from the body sheet is unavoidable, the line light source (including the condensing optical system) and the line sensor (including the condensing optical system) generated during scanning and the distance between the phosphor sheet and the Even a slight change causes a problem that the focus of the excitation light or the stimulated emission light deviates from the light receiving surfaces of the phosphor sheet and the line sensor, respectively. As a result, the quality of the read image is degraded or artifacts occur.

This problem is the same in a solid-state radiation sensor using a linear light source as a reading light source. In addition,
In this case, unlike the radiation image information reading apparatus using the stimulable phosphor sheet, the problem of the focus shift occurs only between the light source (including the condensing optical system) and the solid-state radiation sensor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and eliminates a shift in focus between reading light generated during scanning and light emitted from a detection panel while using a linear light source and a line sensor. It is an object of the present invention to provide a radiation image information reading device capable of obtaining a high quality radiation image.

[0013]

According to a first radiographic image information reading apparatus of the present invention, a change in the distance between a detection panel and a linear light source (to be described later) which occurs during scanning (including the inclination of the linear light source or the detection panel). A linear light source that projects linear reading light on the surface of the detection panel on which the radiation image information is recorded, with the aim of eliminating a focus shift of the reading light caused by the above and obtaining a high quality radiation image, According to the radiation image information recorded on the irradiated portion of the detection panel by the irradiation of the linear reading light, the irradiated portion or the back surface side portion of the detection panel corresponding to the irradiated portion A light-receiving unit for receiving light emitted from a light source and performing photoelectric conversion, and scanning means for moving one of the linear light source and the detection panel relative to the other in a direction different from the linear length direction And the scanning Reading means for sequentially reading the output from the light receiving section at each position moved by the means in accordance with the movement, wherein the linear read light is constantly detected during the movement. The apparatus further comprises a reading light focus control means for adjusting the focus of the reading light so as to form an image on a panel.

Here, the linear light source is a light source that linearly irradiates the detection panel with the reading light, and may be a light source itself that emits a linear reading light, or a non-linear light source. And a condensing optical system that condenses reading light from the light source on the detection panel in a linear manner.

The first radiation image information reading apparatus of the present invention may be a radiation solid state sensor or a radiation image information reading apparatus using a stimulable phosphor sheet. In the case of (1), the detection panel is the radiation solid-state sensor, and in the case of a radiation image information reading apparatus using a stimulable phosphor sheet, the detection panel is a stimulable phosphor sheet.

Further, in the first radiation image information reading apparatus of the present invention, a laser, an LED array, an organic EL or the like can be applied as a light source of the reading light.

Further, the direction of moving one of the linear light source and the detection panel relative to the other by the scanning means (the direction different from the linear length direction) is as follows.
It is desirable that the direction is substantially orthogonal to the length direction, that is, the short axis direction, but it is not limited to this direction. For example, it is possible to irradiate the reading light uniformly over substantially the entire surface of the detection panel. Within a possible range, it may be moved in an oblique direction deviating from a direction substantially orthogonal to the linear length direction, or may be moved in a zigzag manner by changing the moving direction, for example. Good.

The reading light focus control means includes:
By performing focus control of the reading light, during the movement,
Any light source may be used as long as it can always form an image of the reading light on the irradiation part of the detection panel without a focus shift. For example, a distance measuring unit that measures the distance between the linear light source and the detection panel and a position adjusting unit that adjusts the position of the linear light source are provided, and during the movement,
The reading light focus control unit may be configured to perform a focus control of the reading light by adjusting a position of the linear light source so as to keep a distance between the linear light source and the detection panel substantially constant. . The distance measuring means may be an electromagnetic one or an optical one.

The distance measuring means and the position adjusting means may be of any type and may be installed at any position as long as the respective objects (distance measurement, position adjustment) can be achieved. However, a relatively hard detection panel (a solid-state radiation sensor or a rigid-type stimulable phosphor sheet) hardly bends during the movement process.
Since it is inclined in the length direction and often causes a focus shift of the reading light, the above-described reading light focus control means is installed at two locations on both sides in the length direction of the linear light source, and It is preferable to eliminate the focus shift of the reading light due to the inclination.

In the case of a linear light source comprising an exposure light source for emitting reading light and a reading light condensing optical system for linearly condensing the reading light from the exposure light source on the detection panel, the moving light source is particularly movable. In the case of a soft detection panel which is often deflected to cause a focus shift of the reading light, the reading light focusing control means adjusts the position of the reading light focusing optical system during the movement to adjust the reading light. It is preferable to perform the focus control. As the reading light focus control means in this case, any means can be used as long as it can adjust the position of the reading light condensing optical system and perform focus control of the reading light. The mechanism is a preferred example. In addition,
In such a case, the reading light focus control means including the distance measuring means and the position adjusting means described above can be applied. However, in order to simplify the control, only the condensing optical system of the reading light is moved. Thus, it is desirable to eliminate the focus shift of the reading light.

Further, it is preferable that the linear light source and the reading light focus control means are integrated.

The description of the linear light source, the scanning means, and the reading light focus control means up to this point will be described with reference to a second radiation image information reading apparatus, which will be described later, that is, using a linear light source and a line sensor. The present invention can also be applied to an apparatus that reads radiation image information recorded on a phosphor sheet.

The second radiation image information reading apparatus of the present invention collects the stimulating light emitted from the stimulable phosphor sheet on the light receiving surface of the line sensor without defocusing, thereby obtaining a high quality radiation image. A linear light source that linearly irradiates reading light to a part of the stimulable phosphor sheet on which the stimulable radiation image information is recorded, and a linearly irradiated part of the phosphor sheet or A photostimulated luminescence light condensing optical system for condensing photostimulated light emitted from the back surface side portion of the phosphor sheet corresponding to the irradiated portion on a light receiving surface of a line sensor described below; A line sensor configured to receive the stimulated emission light condensed by an optical optical system, perform photoelectric conversion, and include at least a plurality of photoelectric conversion elements arranged in a length direction of the linearly irradiated portion; And the linear light source and the luminous emission A light condensing optical system and the line sensor; a scanning unit for moving one of the phosphor sheets relative to the other in a direction different from the length direction; and each position moved by the scanning unit. Reading means for sequentially reading the output of the photoelectric conversion element in accordance with the movement in each case, during the movement, the stimulated emission light is always imaged on the light receiving surface of the line sensor. In this way, the apparatus further comprises a stimulating light emission focus control means for adjusting the focus of the stimulating light.

That is, the second radiographic image information reading apparatus of the present invention uses a linear light source as a reading light source (excitation light source), and irradiates the stimulable fluorescent light with irradiation of linear excitation light from the linear light source. This is for obtaining a radiation image signal by receiving the photostimulated light emitted from the body sheet using the line sensor and performing photoelectric conversion, and is used for movement (sub-scanning) of the linear light source and the line sensor. The resulting shift in focus of the stimulating light is eliminated, and the stimulating light is always imaged on the light receiving surface of the line sensor.

Here, the stimulating luminescence light focusing control means keeps the distance between the stimulating luminescence light condensing optical system and the line sensor constant, and controls the stimulating luminescence light condensing optical system and the line sensor. And, using a distance measuring means for measuring the distance to the stimulable phosphor sheet, and a position adjusting means for adjusting the positions of the stimulating luminescence light condensing optical system and the line sensor, during the movement, Adjusting the positions of the stimulating luminescence light condensing optical system and the line sensor so as to keep the distance between the stimulating luminescence light condensing optical system and the line sensor and the detection panel substantially constant, and stimulating luminescence. It is desirable to perform light focus control, particularly in the case of a relatively hard detection panel, for the reason described in the above description of the read light focus control means. Further, the distance measuring means may be an electromagnetic one or an optical one.

The distance measuring means and the position adjusting means may be of any type and may be installed at any position as long as the respective objects (distance measurement, position adjustment) can be achieved. It is preferable that two light-emitting light condensing optics and the line sensor be provided on both sides in the length direction of the line sensor.

Further, as described in the reading light focus control means described above, in the case of a particularly soft detection panel, the stimulable luminescence light focus control means controls only the stimulus luminescence light focusing optical system during the movement. It is preferable that the focus control of the stimulating light is performed by adjusting the position of the stimulating light. Also in this case, the automatic focusing mechanism of the camera is a preferable example.

It is preferable that the second radiation image information reading apparatus of the present invention further includes a reading light focus control means of the first radiation image information reading apparatus in addition to the stimulated emission light focusing control means.

[0029] In addition, the innovation of the semiconductor microfabrication technology has significantly improved the performance such as increase in the number of pixels, improvement in sensitivity, reduction of noise, and reduction in image size. In the above, it is preferable that a photoelectric conversion element constituting the line sensor is a CCD.

[0030]

The first radiographic image information reading apparatus according to the present invention is a radiographic image information reading apparatus using a solid-state radiation sensor or a stimulable phosphor sheet. The reading light is always connected to the detection panel to be read. Since the reading light focus control means is provided so as to form an image, a change in the distance between the linear light source (including the reading light focusing optical system) and the detection panel during scanning (the inclination of the linear light source or the detection panel). ) Can be eliminated.

The reading light focus control means of the present invention comprises: a distance measuring means for measuring a distance between the linear light source and the detection panel; and a position of the linear light source such that the reading light is always imaged on the detection panel. The configuration with the position adjusting means for adjusting is very effective in the case of a relatively hard detection panel. If two focus control means are provided on both sides of the linear light source, it is particularly effective for eliminating the focus shift of the reading light due to the inclination of the relatively hard detection panel.

Further, the reading light focus control means of the present invention adjusts not the position of the entire linear light source but the position of only the reading light condensing optical system of the linear light source by using a mechanism such as an auto focus. If the configuration is such that the focus of the reading light is adjusted, the control is simplified, and it is particularly effective in the case of a soft detection panel in which the focus of the reading light shifts due to bending during scanning.

A second radiographic image information reading apparatus according to the present invention is a radiographic image information reading apparatus using a stimulable phosphor sheet. The stimulable luminescent light from the stimulable phosphor sheet is always defocused. Since it is equipped with a stimulating luminescence light focus control unit that focuses on the light receiving surface of the line sensor,
During scanning, stimulated emission light and condensing optics and stimulated emission light caused by fluctuations in the distance between the detection panel and the stimulating emission light and condensing optical system or inclination of the detection panel are included. Focus shift can be eliminated.

Similarly to the reading light focus control means of the first radiation image information reading apparatus, the stimulable luminescence light focus control means of the present invention comprises a distance (stimulation luminescence light and stimulus luminescence light focusing optical system). And a detection panel) may be constituted by measuring means and position adjusting means (position of the stimulated emission light and the stimulated emission light condensing optical system). It may be configured to adjust only the position. Each of these stimulated emission light focus control means can be effective for a hard and soft detection panel.

Further, if the reading light focus control means of the first radiation image information reading device is applied to the second radiation image information reading device of the present invention, the focus deviation of both the reading light and the stimulated emission light can be reduced. Can be eliminated.

In the first and second radiographic image information reading apparatuses of the present invention, if the linear light source and the reading light focus control means are formed integrally, the whole apparatus can be made compact and the installation can be safely performed. Sex and convenience are also achieved.

As described above, since the radiation image information reading apparatus is provided with the reading light focus control means and the stimulating light emitting light focus control means, it is possible to prevent the focus shift of the reading light and the stimulating light emission light. It is possible to obtain a perfect radiation image.

[0038]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a radiation image information reading apparatus A to which the first embodiment of the radiation image information reading apparatus of the present invention is applied, and FIG. 2 is a perspective view of the radiation image information reading apparatus A shown in FIG. 3 is a cross-sectional view showing a cross section taken along the line I. FIG. 3 is a sectional view showing the detailed configuration of the excitation light focus control unit 60 of the radiation image information reading apparatus A shown in FIGS. 2, the direction perpendicular to the plane of the drawing (in the direction perpendicular to the plane of the drawing) (from the stimulable phosphor sheet 50 to the exposure light source BLD11).
Part).

In the illustrated radiation image information reading apparatus A, the front end and the rear end of the stimulable phosphor sheet 50 (the front end and the rear end have no or no radiation image recorded thereon). Is not an area of interest), and transports the sheet in the direction of arrow Y by supporting the transport belt 4.
0, a BLD 11 that emits a linear excitation light L in a direction substantially orthogonal to the surface of the sheet 50, a collimator lens that collects the linear excitation light L emitted from the BLD 11, and a toric lens that expands the beam only in one direction. The optical system 12, which irradiates the linear excitation light L to the surface of the sheet 50, the BLD 11, the support 13 of the optical system 12, and the linear excitation light L from the optical system 12 scans (the sheet by the belt 40). An excitation light focus control unit 60 that controls the focus of the excitation light so that an image is always formed on the surface of the sheet 50 without a focus shift during the movement of the arrow 50 in the direction of the arrow 50), and an optical axis substantially orthogonal to the surface of the sheet 50. A line sensor 20 to be described later is configured to emit 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 irradiation of the excitation light L. Refractive index distribution type lens array (a lens in which a large number of refractive index distribution type lenses are arranged; hereinafter, referred to as a selfoc lens array) 16 for condensing light on the light receiving surface of each photoelectric conversion element 21 The excitation light cut filter 17 that cuts the excitation light L mixed with the stimulable luminescence light M incident on 16, and each photoelectric conversion element 21 that receives the stimulus luminescence light M transmitted through the excitation light cut filter 17 and performs photoelectric conversion. Image information reading means 30 for outputting signals output from the arrayed line sensors 20 and the respective photoelectric conversion elements 21 constituting the line sensors 20 to the image processing apparatus in correspondence with the portions of the sheet 50
It is a configuration provided with.

The distance between the BLD 11 and the optical system 12 is always constant and is supported by the support 13.

The selfoc lens array 16 is an image plane which forms a one-to-one image of the light emission area of the stimulating light M on the back surface of the sheet 50 on the light receiving surface of each photoelectric conversion element 21 of the line sensor 20. It works. Further, the optical system 12 composed of a collimator lens and a toric lens is
The excitation light L from D11 is expanded on the sheet 50 to a desired irradiation area.

More specifically, the line sensor 20 includes a large number (for example, 1000 or more) of photoelectric conversion elements 21 arranged at least along the arrow X direction. Specifically, an amorphous silicon sensor, a CCD, a MOS image sensor, or the like can be applied as the photoelectric conversion element 21. Here, a CCD is used.

The excitation light focus control unit 60 includes the BLD 1
1, the optical system 12, the support table 13, and an actuator composed of a DC motor 61, a leaf spring 63, and a damper 64 for preventing resonance, as shown in FIG. The configuration includes a distance sensor 65 installed on both sides of the system 12 and a driver 62 for adjusting the position of the support base 13 by rotation of a DC motor. The distance sensor 65 that measures the distance between the optical system 12 and the sheet 50 may be any of an electromagnetic type and an optical type. Here, two PSDs 66 that emit infrared laser beams are used as an example. Use the optical type used. Further, the support 13 is provided with a PSD of the distance sensor 65.
Laser light from the laser and excitation light L from the BLD 11
It is made of a material that transmits light.

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 moved in the direction of arrow Y (in FIG. Direction). 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
Is input to

On the other hand, the BLD 11 has a line width of about 100 μm.
Is emitted in a direction substantially orthogonal to the surface of the sheet 50, and 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. Then, the light enters the sheet 50 substantially perpendicularly. At this time, the excitation light L is applied on the surface of the sheet 50 in a linear shape (line width d _L substantially 100
μm).

The linear excitation light L incident on the sheet 50 is
From the vicinity of the irradiation area (line width d _L shown 100 [mu] m) and the irradiation zone, stimulated emission M having an intensity corresponding to the radiation image information recorded therein is emitted. At the same time, the stimulated emission light M that has passed through the transparent support of the sheet 50 is emitted from the back side of the sheet 50.

The stimulated emission light M emitted from the back side of the sheet 50 enters the selfoc lens array 16, passes through the excitation light cut filter 17, and after the mixed excitation light L is cut. Light is condensed on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20.

The line sensor 20 photoelectrically converts the stimulated emission light M received by each CCD 21 and converts each signal obtained by the photoelectric conversion into image information corresponding to a portion of the sheet 50 by the reading means 30. Is output to an external image processing device or the like, and is used for reproducing a diagnostic image.

By performing the above-described process on the entire scanning area of the sheet 50 by conveying the belt 40, radiation image information recorded on the sheet 50 is obtained.

During the scanning, the PSD 6 of the distance sensor 65
6, an infrared laser beam is emitted to the surface of the sheet 50 and the reflected light is measured, whereby the support 13
The distance between the sheet and the sheet 50 is measured. The distance measured by the distance sensor 65 is converted into an electric signal by the distance sensor 6.
5 is sent to the control circuit of the DC motor 61 electrically connected to the control circuit 5. If the measured distance is different from the optimal distance set in advance (in other words, the distance at which the excitation light L is imaged on the surface of the sheet 50 without a focus shift), the DC motor 61 operates and the driver 62 The position of the support 13 is adjusted. Since the BLD 11 and the optical system 12 are both supported by the support 13, the distance between the BLD 11 and the optical system 12 and the sheet 50 is always kept at the optimum distance.

As described above, according to the radiation image information reading apparatus A of the present embodiment, the distance between the support 13 and the sheet 50 (the distance between the BLD 11 and the optical system 12 and the sheet 50) during scanning is determined by the distance sensor. 65, the excitation light L from the BLD 11 is always irradiated onto the surface of the sheet 50 without any focus shift by always adjusting the distance between the support table 13 and the sheet 50 to the optimum distance using the DC motor 61. This makes it possible to obtain a high-quality read image. Further, since two distance sensors 65 and two DC motors 61 are provided on both sides of the BLD 11 and the optical system 12 along the direction of the arrow X, it is particularly effective to prevent the sheet 50 from tilting in the X direction during scanning. is there. Further, the excitation light focus control unit 60 controls the excitation light source (BL
Since it is formed integrally with D11 and the optical system 12), the security is high and the installation is easy.

In this embodiment, the stimulable phosphor sheet is used as the detection panel on which the radiation image information is recorded. However, the detection panel to be read in the present invention is not limited to the stimulable phosphor sheet. For example, in the case of a radiation solid-state sensor using a linear reading light source, the same effect can be obtained by applying the mechanism of the excitation light focus control unit 60 shown in FIG. In this case, when the support is used, the material of the light-transmitting portion of the support needs to have a property of transmitting the reading light of the radiation solid-state sensor and the light of the distance sensor.

Here, the BLD 11 and the optical system 12
By adjusting the distance between the support 13 and the sheet 50, that is, the distance between the BLD 11 and the optical system 12 and the sheet 50 by using a distance sensor 65 and an actuator, the reading light (the excitation light in this example) is adjusted. Although the focus deviation of L) is eliminated, the reading light focus control means of the present invention is not limited to the above, and may be of any type as long as it can eliminate the focus deviation of the reading light. Is also good. For example, the position of the exposure light source (BLD 11 in this embodiment) is fixed, and only the position of the reading optical system (optical system 12 in this embodiment) is adjusted during scanning so that the excitation light L is applied to the surface of the sheet 50. The focus of the excitation light L may be controlled so as to form an image. In this case, since the position is controlled only for the reading optical system,
It has the advantage of easy control.

FIG. 4 is a perspective view showing a radiation image information reading apparatus B to which the second embodiment of the radiation image information reading apparatus of the present invention is applied, and FIG. 5 is a perspective view of the radiation image information reading apparatus B shown in FIG. 6 is a cross-sectional view showing a cross section taken along the line I, and FIG. 6 is a sub-scanning direction (arrow X direction, arrow X direction) for showing a detailed configuration of the stimulating emission light focus control unit 70 of the radiation image information reading apparatus B shown in FIGS. FIG. 5 is a cross-sectional view (a section from the sheet 50 to the line sensor 20) in a direction perpendicular to the paper surface.

In the illustrated radiation image information reading apparatus B, the front end and the rear end of the stimulable phosphor sheet 50 (the front end and the rear end have no or no radiation image recorded thereon). Is also not a region of interest), the transport belt 40 transporting the sheet in the direction of arrow Y (the direction perpendicular to the paper surface in FIG. 6), and applying the linear excitation light L to the surface of the sheet 50 substantially. B emitted in the orthogonal direction
The sheet 50 comprises a combination of a collimator lens for condensing the linear excitation light L emitted from the LD 11 and the BLD 11 and a toric lens for expanding the beam only in one direction.
Optical system 12 for irradiating linear excitation light L on the surface, sheet 5
The stimulated emission light M having an optical axis substantially orthogonal to the surface of the sheet 50 and 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 excitation light L will be described later. A selfoc lens array 16 for condensing light on a light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20, and an excitation light cut filter for cutting excitation light L mixed with stimulated emission light M incident on the selfoc lens array 16. 17, a line sensor 20 in which photoelectric conversion elements 21 for receiving and stimulating the stimulating light M transmitted through the excitation light cut filter 17 are arranged, the SELFOC lens array 16, the excitation light cut filter 17 and the line sensor During the scanning (movement of the sheet 50 in the direction of the arrow Y by the belt 40), the line sensor 2 is constantly scanned by the stimulating light M from the support 18 and the sheet 50.
And the line sensor 2 for controlling the focus of the stimulated emission light so that an image is formed on the surface of each of the photoelectric conversion elements 21 without focus shift.
The configuration is provided with image information reading means 30 for outputting a signal output from each photoelectric conversion element 21 constituting 0 to an image processing apparatus in correspondence with a portion of the sheet 50.

The selfoc lens array 16 is an image surface on the light receiving surface of each photoelectric conversion element 21 of the line sensor 20 which forms a one-to-one image of a light emission area of the stimulating light M on the back surface of the sheet 50. It works. Further, the optical system 12 composed of a collimator lens and a toric lens is
The excitation light L from D11 is expanded on the sheet 50 to a desired irradiation area.

More specifically, the line sensor 20 includes a large number (for example, 1000 or more) of photoelectric conversion elements 21 arranged at least along the arrow X direction. Specifically, an amorphous silicon sensor, a CCD, a MOS image sensor, or the like can be applied as the photoelectric conversion element 21. Here, a CCD is used.

The distance between the SELFOC lens array 16 and the line sensor 20 is always constant and is supported by the support 18.

As shown in FIG. 6, the stimulating light emission focus control unit 70 includes a DC motor 71 and a leaf spring 7.
A configuration including an actuator including the actuator 3 and a damper 74 for preventing resonance, a distance sensor 75 provided on both sides of the SELFOC lens array 16, and a driver 72 for adjusting the position of the support base 18 by rotation of the DC motor 71. It is. The distance sensor 75 for measuring the distance between the support 18 and the sheet 50 may be any of an electromagnetic type and an optical type. Here, for example, two PSDs 76 that emit infrared laser beams are used. Use the optical type used. Further, the support table 18 is a PSD of the distance sensor 75.
And a material that transmits infrared laser light from the sheet and stimulated emission light from the sheet 50.

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

First, as the transport belt 40 moves in the direction of the 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 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 image information reading means 30.

On the other hand, the BLD 11 has a line width of about 100 μm.
Is emitted in a direction substantially orthogonal to the surface of the sheet 50, and 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. Then, the light enters the sheet 50 substantially perpendicularly. At this time, the excitation light L is applied on the surface of the sheet 50 in a linear shape (line width d _L substantially 100
μm).

The linear excitation light L incident on the sheet 50 is
From the vicinity of the irradiation area (line width d _L shown 100 [mu] m) and the irradiation zone, stimulated emission M having an intensity corresponding to the radiation image information recorded therein is emitted. At the same time, the stimulated emission light M that has passed through the transparent support of the sheet 50 is emitted from the back side of the sheet 50.

The stimulated emission light M emitted from the back side of the sheet 50 enters the selfoc lens array 16, passes through the excitation light cut filter 17, and cuts the mixed excitation light L. Light is condensed on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20.

The line sensor 20 photoelectrically converts the stimulated emission light M received by each CCD 21, and makes each signal obtained by the photoelectric conversion correspond to a portion of the sheet 50 by the reading means 30. Is output to an external image processing device or the like, and is used for reproducing a diagnostic image.

By performing the above-described process on the entire scanning area of the sheet 50 by conveying the belt 40, radiation image information recorded on the sheet 50 is obtained.

During the scanning, the PSD 7 of the distance sensor 75
6, an infrared laser beam is emitted to the surface of the sheet 50, and the reflected light is measured.
The distance between the sheet and the sheet 50 is measured. The distance measured by the distance sensor 75 is converted into an electric signal by the distance sensor 7.
5 is sent to a control circuit of the DC motor 71 electrically connected to the DC motor 71. If the measured distance is different from the preset optimum distance (in other words, the distance at which the stimulating light M is imaged on the light receiving surface of each CCD 21 of the line sensor 20 without a focus shift), the DC motor 71 Is operated to adjust the position of the support base 18 through the driver 72. Since the line sensor 20 and the SELFOC lens 16 are both supported by the support 18, by adjusting the position of the support 18, the distance between the line sensor 20 and the SELFOC lens array 16 and the sheet is reduced. It is always kept at the optimum distance.

As described above, according to the radiation image information reading apparatus B of this embodiment, the distance between the support table 18 and the sheet 50 is measured by the distance sensor 75 during scanning, and the DC motor 7
By always adjusting the distance between the support base 18 and the sheet 50 to the optimum distance by using 1, the excitation light M from the sheet 50 is always irradiated to the light receiving surface of each CCD 21 of the line sensor 20 without a focus shift. Accordingly, it is possible to obtain a high-quality read image. Further, since two distance sensors 75 and two DC motors 71 are provided on both sides of the SELFOC lens array 16 along the arrow X direction, the focus of photostimulated emission light caused by the sheet 50 tilting in the X direction during scanning. It is particularly effective for preventing displacement.

In this embodiment, the distance between the line sensor 20 and the SELFOC lens array 16 is kept constant,
By using the distance sensor 75 and the actuator to adjust the distance between the support base 18 and the sheet 50, that is, the distance between the line sensor 20 and the SELFOC lens array 16 and the sheet 50, the focus shift of the photostimulated light M can be eliminated. However, the stimulating luminescence light focus control means of the present invention is not limited to the above, and may be of any type as long as it can eliminate the focus shift of the stimulating luminescence light. For example, the position of the line sensor is fixed, and only the position of the optical system for condensing stimulated emission light (the selfoc lens array 16 in the present embodiment) is adjusted during scanning so that the stimulated emission light is transmitted to each of the line sensors. The focus of the stimulated emission light may be controlled so that an image is formed on the light receiving surface of the photoelectric conversion element. In this case, since the position is controlled only for the optical system for condensing stimulated emission light, there is an advantage that control is easy.

Here, for convenience of explanation, only the stimulated emission light focus control unit 70 is provided in the radiation image information reading apparatus B, but the second radiation image information reading apparatus of the present invention has As shown in FIG. 7, the excitation light focus control unit 60 shown in FIG. The stimulated emission light focus control means and the excitation light focus control means are not limited to the stimulated emission light focus control unit 70 and the excitation light focus control unit 60 shown in FIG. The focus of the stimulated emission light can be controlled by forming an image on the light receiving surface of each photoelectric conversion element, and the focus of the excitation light is controlled by forming the excitation light on the surface of the phosphor sheet Anything that can do so may be used.

According to the radiation image information reading apparatus as shown in FIG. 7, since the focus shift of both the excitation light and the stimulating light can be eliminated, a higher quality read image can be obtained.

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. Sensors and various known configurations can be employed. 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, the radiation image information reading apparatus of each of the above-described embodiments uses the stimulable phosphor sheet whose support is made of a stimulable luminescent light-transmitting material, so that the excitation light source BLD11 and the line sensor can be used. 20 is disposed on different sides of the sheet from each other to receive a stimulated emission light emitted from a surface opposite to the sheet surface on which the excitation light is incident. The radiation image information reading apparatus according to the embodiment of the present invention is not limited to the one having such a configuration. As shown in FIG. 8, both the excitation light source BLD11 and the line sensor 20 are disposed on the same side of the sheet. And a reflection light condensing type configuration for receiving the stimulating light M emitted from the sheet surface on which the exciting light L is incident, the stimulating light focusing control means and the stimulating light Emitting light four By applying the scan control means, it is possible to obtain the same effect.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a first radiation image information reading apparatus of the present invention.

FIG. 2 is a perspective view of the radiation image information reading apparatus A shown in FIG.
Sectional view showing section I-line

FIG. 3 is a diagram for explaining an excitation light focus control unit of the radiation image information reading apparatus A shown in FIGS. 1 and 2;

FIG. 4 is a schematic view showing an embodiment of a second radiation image information reading apparatus according to the present invention;

FIG. 5 is a diagram illustrating an I- of the radiation image information reading apparatus B illustrated in FIG. 4;
Sectional view showing section I-line

FIG. 6 is a diagram for explaining a stimulated emission light focus control unit of the radiation image information reading apparatus B shown in FIGS. 4 and 5;

FIG. 7 is a diagram showing another embodiment of the radiation image information reading apparatus of the present invention.

FIG. 8 is a diagram showing another configuration of the radiation image information reading apparatus according to the present invention.

[Explanation of symbols]

Reference Signs List 11 broad area laser (BLD) 12 optical system composed of collimator lens and toric lens 13, 18 support base 16 selfoc lens array 17 excitation light cut filter 20 line sensor 21 CCD 30 image information reading means 40 scanning belt 50 stimulable phosphor Sheet 60 Excitation light focus control unit 61, 71 DC motor 62, 72 Driver 63, 73 Leaf spring 64, 74 Dambar 65, 75 Distance sensor 66, 76 PSD 70 Stimulated emission light focus control unit L Excitation light M Stimulated emission light

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) G21K 4/00 H04N 1/04 EF term (reference) 2G083 AA03 AA04 BB04 CC10 DD11 DD16 DD18 EE02 2H013 AC03 5B047 AA17 BB02 BC05 CA17 CB04 CB10 5C072 AA01 BA17 DA03 DA23 EA05 VA01

Claims (13)

[Claims] 1. A linear light source for projecting a linear reading light onto a surface of a detection panel on which radiation image information is recorded, and a linear light source recorded on an irradiated portion of the detection panel by the irradiation of the linear reading light. A light receiving unit that receives light emitted from the irradiated portion or a back side portion of the detection panel corresponding to the irradiated portion and performs photoelectric conversion according to the radiation image information, and the linear light source Scanning means for moving one of the detection panels relative to the other in a direction different from the linear length direction, and an output from the light receiving unit at each position moved by the scanning means. A radiation image information reading device comprising: a reading unit that sequentially reads in accordance with the movement, wherein the linear reading light is always imaged on the detection panel during the movement. focus Radiation image information reading apparatus characterized by further comprising a light focus controlling unit reading for performing integer. 2. The radiation image information reading device according to claim 1, wherein the detection panel is a light-readout type solid-state radiation sensor. 3. The radiation image information reading apparatus according to claim 1, wherein the detection panel is a stimulable phosphor sheet. 4. A linear light source for irradiating a part of a stimulable phosphor sheet on which radiation image information is stored and recorded with a reading light in a linear manner; A stimulated emission light condensing optical system for condensing the stimulated emission light emitted from the back surface side portion of the phosphor sheet corresponding to the irradiated portion on a light receiving surface of a line sensor described below; A line sensor comprising a plurality of photoelectric conversion elements arranged in the length direction of at least the linearly irradiated portion, receiving the stimulated emission light collected by the optical system and performing photoelectric conversion. The linear light source and the stimulated emission light condensing optical system and the line sensor, and a scanning unit that moves one of the phosphor sheets relative to the other in a direction different from the length direction; Each position moved by the scanning means A reading unit for sequentially reading the output of the photoelectric conversion element in each case according to the movement, wherein the stimulated emission light is always received on the light receiving surface of the line sensor during the movement. A stimulating luminescence light focus control means for adjusting the focus of the stimulating luminescence light so that an image is formed on the radiation image information reading apparatus. 5. A stimulable luminescence light condensing optical system and a distance between the line sensor are always constant, and the stimulus luminescence light focus control means includes a stimulus luminescence light condensing optical system and the line sensor. And, a distance measuring means for measuring the distance to the stimulable phosphor sheet, and a position adjusting means for adjusting the position of the stimulating luminescence light condensing optical system and the line sensor, during the movement, Adjusting the positions of the stimulating luminescence light condensing optical system and the line sensor so as to keep the distance between the stimulating luminescence light condensing optical system and the line sensor and the detection panel substantially constant, and stimulating luminescence. 5. The radiation image information reading apparatus according to claim 4, wherein focus control of light is performed. 6. The apparatus according to claim 5, wherein the distance measuring means and the position adjusting means are provided at two places on both sides in the length direction of the stimulated emission light condensing optical system and the line sensor. The radiation image information reading device according to the above. 7. The stimulable luminescence light focus control means,
5. The radiation image information reading apparatus according to claim 4, wherein during the movement, a focus control of the stimulating light is performed by adjusting a position of the stimulating light condensing optical system. 6. 8. The radiation image information reading apparatus according to claim 4, wherein the photoelectric conversion element is a CCD. 9. A reading light focus control means for adjusting a focus of the reading light so that the linear reading light is always imaged on the detection panel during the movement. Item 9. The radiation image information reading device according to any one of Items 4 to 8. 10. The radiation image information reading apparatus according to claim 1, wherein the reading light focus control means and the linear light source are formed integrally. 11. The reading light focus control means includes a distance measuring means for measuring a distance between the linear light source and the detection panel, and a position adjusting means for adjusting a position of the linear light source. The focus control of the reading light is performed by adjusting a position of the linear light source so as to keep a distance between the linear light source and the detection panel substantially constant. The radiation image information reading device according to the above. 12. The radiation image information reading apparatus according to claim 11, wherein the distance measuring means and the position adjusting means are provided at two places on both sides of the linear light source in the length direction. 13. The reading device according to claim 1, wherein the linear light source includes an exposure light source that emits reading light, and a reading light focusing optical system that linearly collects the reading light from the exposure light source on the detection panel. 11. The radiation image information reading apparatus according to claim 1, wherein the optical focus control unit performs focus control of the reading light by adjusting a position of the reading light condensing optical system during the movement. apparatus.