JPS62172858A - Radiation picture reader - Google Patents

Abstract

PURPOSE:To obtain laser light of high output by single laser light, and to improve the performance of the titled reader by irradiating linearly a laser beam from a semiconductor laser light source, on radiation picture information recording medium by a polarizing means, and moving relatively a medium by a sub-scanning means in the direction roughly vertical to this irradiated laser light. CONSTITUTION:Laser light A from an integrated semiconductor laser light source 1 is made parallel by a collimator lens 7 and made incident on a laser deflecting means 2. The laser light is irradiated so as to execute linearly a main scan in the sub-direction, to a radiation image converting panel 4 functioning as a radiation image recording medium which has been carried on a sub-scanning means 3 by this means 2 and a Ftheta lens 8. The means 3 which has been carried by this panel 4 is moved relatively in the direction roughly vertical to the direction of the main scan of the laser light A. Also, picture information of the panel 4 is brought to accelerated light emission, its accelerated light emission is made incident on an accelerated light emission condenser 5, high output laser light is outputted by a single laser light source, and the performance of a reader is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a radiation image reading device that scans the surface of a radiation image information recording medium with a laser beam and reads radiation image information recorded on the surface of the recording medium. It is something.

[Background of the invention]

Radiographic images such as X-ray images are often used for medical purposes. One way to obtain this radiographic image is to irradiate a phosphor layer (phosphor screen) with radiation that has passed through the subject, thereby producing visible light, which is then irradiated onto a film coated with a silver salt photosensitive material. Develop. There is a so-called radiographic method.

In recent years, with advances in radiation image diagnosis technology, methods have been devised for reading radiation image information recorded in radiographs, converting it into a digital signal, and then reproducing it on a CRT or photosensitive material. As a result, more diagnostic information can be obtained from the - times of radiography, improving diagnostic performance and radiation exposure. This will bring about a reduction in

It is also expected to improve the efficiency of storing and retrieving radiation image information.

In the radiation image information reading device using photographic film, a photographic film on which a radiation image is recorded is exposed and scanned with image reading light, and the reflected light or transmitted light is detected by a photodetector and converted into an electrical signal. is being carried out.

On the other hand, methods for obtaining radiographic image information without using radiographic films made of silver salt photosensitive materials have been devised.

In such a method, the radiation transmitted through the object is absorbed by a certain kind of phosphor, and then this phosphor is excited with light or thermal energy, so that the phosphor accumulates from the absorption. There are devices that emit radiation energy as fluorescence, detect this fluorescence, and create images. Specifically, for example, U.S. Patent No. 3.
It is disclosed in No. 859,527 or Japanese Patent Application Laid-open No. 12144/1983. This is a radiation image conversion method that uses a stimulable phosphor and uses visible light or infrared rays as stimulable excitation light, and uses a radiation image conversion panel with a stimulable phosphor layer formed on a support. Then, the radiation transmitted through the object is applied to the photostimulable phosphor layer of this radiation image conversion panel, and radiation energy corresponding to the radiation transmittance of each part of the object is accumulated to form a latent image. By scanning the phosphor layer with the stimulated excitation light, the radiation energy accumulated in each part of the panel is emitted and converted into light, and a radiation image is obtained by an optical signal depending on the intensity of this light. . Another method is selenium, which uniformly charges radiation that passes through the subject.

After forming an electrostatic latent image by absorbing it into a semiconductor panel having a photoconductor layer such as silicon, the electrostatic latent image on the panel is electrically detected by scanning the semiconductor panel with light. There are things that can be visualized (for example, Japanese Patent Application Laid-Open No. 54-3)
No. 1219).

The radiographic images obtained in this way may be processed as they are, or processed in real time, such as spatial frequency processing and gradation processing, to form a silver halide film.

It is output to CRT etc. and visualized, or semiconductor record 1
! ! device, magnetic storage device, optical disk storage device, etc., and then these image records f, #! are stored as needed. The image is taken out from the device and output to a silver halide film, CRT, etc. for visualization.

By the way, the image reading light of the radiation image reading device used in the various methods described above is generally a gas laser, for example, a laser beam.
Le-Ne lasers, ^r° lasers, etc. have been used, but gas lasers are large in size, consume a lot of power, generate 1° of heat, and require an optical system for reading one image. Since it is large-scale, it has many drawbacks such as an increase in the size of the device.

Therefore, the applicants of the present application have already applied for Japanese Patent Application Laid-open No. 59-1
In No. 5933, we proposed a method for reading radiographic images using a laser as a light source for reading one image. did. The device using this method has the advantage that the optical system can be simplified compared to the image reading system of the conventional device using a gas laser, and the device is small and inexpensive. It was difficult to read an image with a sufficiently high signal-to-noise ratio. In other words, if the 9 image reading speed is constant,
This is because when the laser output becomes 1/4, the SN ratio decreases to 1/2.

On the other hand, in recent years, in order to improve the throughput of radiographic image reading devices, there has been a strong desire to increase the image reading speed of the devices. For this purpose, it is necessary to increase the laser output and increase the light intensity. That is, if the SN ratio is constant, doubling the laser output can double the reading speed for one image.

For this reason, various methods for increasing the output power of semiconductor lasers have been studied, and the following methods have been proposed. That is.

(2) A method that uses multiple semiconductor lasers and synthesizes the optical axes of the laser beams generated from them using a deflector or a holographic diffraction grating to achieve high output.

■Equipped with a deflector and a stimulated luminescence concentrator for each of the plurality of semiconductor lasers, each of which is in charge of scanning a different area on the radiation image conversion panel, and focused by the stimulated luminescence concentrator for each area. A method for increasing the reading speed by using light (Japanese Patent Application Laid-open No. 6
0-1) No. 7212, etc.).

(2) A plurality of semiconductor lasers are sequentially pulsed, and a single deflector scans the semiconductor lasers to different areas on the radiation image conversion panel.

There is a method (such as Japanese Patent Application Laid-open No. 108817/1983) in which this is used as a tree scanning line and the stimulated luminescence emitted from each region is collected by a single stimulated luminescence condenser.

However, in the case of (2) above, it is difficult to combine the optical axes of the laser beams, and since each laser beam spot does not converge to one point, the spot diameter of the combined laser beams tends to become large, and the resulting image Sharpness deteriorated. Moreover, there is a limit to the number of laser beams that can be combined.

In addition, in the case of (2) above, since a deflector and a stimulated emission condenser are used for each semiconductor laser, the entire device becomes large, and the initial goal of miniaturizing the laser light source by using a semiconductor laser cannot be achieved. However, this method has the problem that it is difficult to connect the images of the areas read by the respective semiconductor lasers, and the joints tend to appear as streaks on one image.

Furthermore, in the case of (2) above, it can be made smaller than the device (2), but the differences are largely the same and cannot be said to be sufficient for downsizing and lowering the price of the entire device, and in this case, the pulse oscillation The pulse width of a semiconductor laser is 0.1 μsec or less per ship.

The responsiveness of the stimulable phosphor to the stimulable excitation light is lμSe
C, and there was a problem that a sufficient response to the pulsed light of the semiconductor laser could not be obtained, resulting in a decrease in sensitivity.

[Purpose of the invention]

This invention has been made in view of the above-mentioned drawbacks of radiographic image reading devices using radiographic image information recording media, and aims to provide a radiographic image reading device that can read nine images at high speed. The purpose is

Another object of the present invention is to provide a radiation image reading device that can obtain high-quality images with a good signal-to-noise ratio. An object of the present invention is to provide a radiation image reading device that enables the following.

[Structure of the invention]

To achieve the above object, the present invention provides an integrated semiconductor laser light source and a laser beam deflection means for linearly irradiating the laser beam emitted from the integrated semi-quadramid laser light source onto the surface of a radiation image information recording medium.

The radiation image information recording medium is configured with a sub-scanning means that moves the linearly irradiated laser light relative to the direction perpendicular to the linearly irradiated laser light, and a high-output laser light can be obtained with a single laser light source. It is composed of

〔Example〕

Next, the present invention will be described based on embodiments shown in the accompanying drawings.

In FIG. 1, reference numeral 1 denotes an integrated semiconductor laser light source using an integrated semiconductor laser. Laser light A emitted from the integrated semiconductor laser light source 1 is collimated by a collimator lens 7, and the laser light is deflected by a vibrating mirror or the like. It enters means 2. The laser beam A passes through the laser beam deflection means 2 and the f-theta lens (theta lens) 8 to the tumescent phosphor as a radiation image recording medium supported on the upper surface of the sub-scanning means 3 installed below. The radiation image conversion panel 4 used is irradiated in a main scanning manner in a line in the width direction. ``The device is relatively moved in the right angle direction, and in the case shown in Figure 1, a flat head having an electrostatic adsorption +113a on the upper surface is shown, but it goes without saying that an endless belt device may also be used.

As described above (main scanning of the laser beam deflection means 2).

The 40 radiation image conversion panels irradiated with laser light during the sub-scanning by the sub-scanning means 3 emit seed bulbs of accumulated and recorded image information using the laser light as stimulation excitation light, and this light is used for radiation image conversion. The light is incident on a seed bulb light condenser 5 which is close to the panel 4 and has an entrance end surface 5' oriented toward the main scanning line. The light incident from the incident end surface 5' of the seed spherical light emission condenser 5 is transmitted to the photomultiplier tube 6 provided at the other end, where it is converted into an electric signal and the image information processing circuit ( Silver halide films can be used as they are or have been subjected to image processing in real time.

It can be visualized by outputting it to a CRT, etc., or it can be visualized by
Images such as Lα devices, magnetic storage devices, optical disk storage devices, etc. are stored in the 'T'A location, and are then taken out from these image storage devices as needed to be stored on silver halide films, CR
It will be output to T etc. and visualized.

In the present invention, a stimulable phosphor refers to a stimulable phosphor that can be stimulated by optical, thermal, mechanical, chemical, or electrical stimulation (exhaustion excitation) after being irradiated with the first light or high-energy radiation. It is a phosphor that exhibits stimulated luminescence corresponding to the amount of initial light or high-energy radiation irradiation, but from a practical standpoint, it is preferably a phosphor that exhibits stimulated luminescence by seed bulb excitation light of 500 nm or more, especially , is a phosphor that efficiently exhibits stimulated luminescence with respect to light in the oscillation wavelength region of a semiconductor laser. An example of such a stimulable phosphor is the general formula.

(Ba+-x-yMgxCay) FX: eEu
” (However, X is one of Br, Cjl!, and I, and x, y, and e are each 0<X+y≦0
．． 6. xy#O and 10-6≦e≦5×to-”), an alkaline earth fluorohalide phosphor described in JP-A-55-12145. The general formula.

(Ba+-xM'x) FX: yA (However, 1Mf
represents at least one of Mg, Ca, Sr, Zn, and Cd; X represents at least one of C7+, Br, and ■; A represents Eu, Tb, and Ce.

At least one of Tm, Dy, Pr, Ho, Nd, Yb and Er, X and y are OSx≦
0.6 and 0≦y≦0.2), the general formula described in JP-A-55-84389 is: BaFX: xCe, y
A (However.

X is the least of (one of) Ca, Br, and ■.

Δ is at least one of In, TI, Gd, Sm and Zr, and X and y are each O<X≦2
X 10-' and Q<y≦5X10-2. ), the general formula described in JP-A No. 55-160078 is M" FX . Small (also a kind, A is Bed, MgO
,Cab.

SrO, Bad, ZnO, 8l 203. Y2
O3, La2O3, In2O3゜5i02. TiO2
, Zr0z, Ge0z, 5n02. Nb2O5,
At least one of Ta2's and ThO□, L
n is Eu.

Tb, Ce, Tm, Dy, Pr, llo,
is at least one of Nd, Yd, Er, Sm and Gd, X is at least one of C1゜1)r and ■, and X and y are each 5xlO"≦X≦
0.5 and Q<y<0.2.

) is a divalent metal fluorohalide phosphor activated with a rare 1-nuclear element, and any of the following 1. The general formula.

nReX3/mAX'2: xEunR
eX3・mAX'z: xEu, ySm (wherein, Re is at least one of La, Gd, Y, Lu, A is an alkaline earth metal, Ba,
At least one of Sr and Ca, X and X' are F,
(Represents at least one type of 1°Br, and X and y are 1xlO-'<x<3xlO-', 1x
It is a number that satisfies the condition 10-'< y <IXIQ-', and n/m is I X 10-3 < n/m < 7
A phosphor that satisfies the condition:
At least one alkali metal selected from s.

M" is Be, Mg, Ca, Sr, Ba, Zn
, Cd, Cu, and Ni, Mll is at least one divalent metal selected from Sc, Y, La,
Ce, Pr, Nd, Pm, Sm.

Eu, Gd, Tb, Dy, llo, Er,
Tm, Yd, Lu, A6. It is at least one trivalent metal selected from Ga and In. x, x' and X
“ is a type of halogen selected from F, Cf, Br and ■.A is Eu, Tb+Ce, Tm
, Dy+ Pr+ llo, Nd.

Yb, Er+ Gd, Lu, Sm, Y, TI
, Na, Ag+Cu and 1g.

Further, a is a numerical value in the range of 0≦a<0.5, b is a numerical value in the range of 0≦b<0.5, and C is a numerical value in the range of 0≦C<0.
It is a numerical value in the range of 2. ) and the like can be mentioned.

Among the above-mentioned stimulable phosphors, barium fluoride halide phosphors and alkali halide phosphors are particularly preferred because they match well with the oscillation wavelength range of a semiconductor laser.

However, the stimulable phosphor used in the radiation image reading device of the present invention is not limited to the above-mentioned phosphor (
Any phosphor may be used as long as it exhibits stimulated luminescence when irradiated with radiation and then irradiated with stimulated excitation light.

FIG. 2 shows a laser light source 1 using the above-mentioned integrated semiconductor laser, in which 1) is a half-centrifugal body laser. The integrated semiconductor laser 1) consists of a copper block 15 fixed to a cooler 4 placed in an outer housing 13 having a window I2.
installed on. 16 is a photodiode, and 17 is a thermistor. The integrated semiconductor laser 1) is integrated so that when a current is injected, the light stimulated to be emitted within the semiconductor is amplified so that the light can be emitted from a plurality of points, and
It is preferable that each emitted light be of a phase synchronization type that maintains a constant optical phase relationship with each other.
The figure shows an integrated semiconductor laser 1) with a multi-stripe structure, and FIG.
edSubstrate Inner 5tripe
) structure of the integrated semiconductor laser 1) are shown respectively.

The integrated semiconductor laser 1) shown in FIG. 3 has n-Gao, a Alo, a As
A cladding layer 32 is formed on which gas, qaAl
o, oaAs well layer 37 and Gao, e A10
．． An active layer 33 is formed by alternately stacking Z As barrier layers 38 in a multi-quantum well type.
An Alo, 4 As cladding layer 34 is formed, and protons are implanted on the surface of the cladding layer 34 by an ion implantation method with a width a of 6.5 μm and a pitch b of 10 μm.
Zero-order implantation in multiple parallel stripes at m.

After forming the P″GaAs camp layer 35, the Au
/Cr electrode 36 is formed.

The integrated half-gate laser 1) shown in FIG. 4 includes an n-GaAs current blocking layer 42 provided on a p-GaAs substrate 41.

The surface of this layer is etched by chemical etching.
0-order forming a plurality (four in the figure) of ■-shaped channels 43 reaching .

p-Cao, BS 8 to 0.3s 88tsu clad 44
, p-CaO, g281o, (1(IAS' active layer 45, n-Gao, bs8 to G, :lSS8 clad layer 46, n-GaAs camp layer 47) After laminating all 47 layers, electrode 48.49 8 then forming
A coating film having a constant reflectance is formed on the front and rear surfaces of the resonator (not shown) after opening No. 5.

It goes without saying that these integrated semiconductor lasers 1) are better if they are given a unimodal far-field pattern and can be focused on a single spot; Since the phases of the outgoing lights emitted from the points are synchronized, it is possible to achieve high output simply by converging them with a condensing lens.Moreover, this outgoing light can be obtained by simply integrating multiple semiconductor lasers. This is because unlike the light emitted from an asynchronous integrated semiconductor laser, it can be focused into a single fine spot.

It should be noted that the integrated semiconductor laser used in the laser light source 1 is preferably one having a phase-locked multi-stripe structure or a vstss structure, but if there is a suitable one other than this, it is free to use it. be.

Further, although the embodiments of the present invention have been described with reference to a radiation image conversion panel using a tumescent phosphor as a radiation image information recording medium, the same applies to other radiation image information recording media. Of course.

〔Effect of the invention〕

As explained above, since the radiation image reading device of the present invention uses an integrated semiconductor laser light source, the laser light itself generated from the laser light source.

It provides high optical power, enables high-sensitivity image reading, and has a single fine stub.

Since the light can be focused on the image, there is little deterioration in sharpness when reading one image.

Further, according to the present invention, the signal to noise ratio of the read signal is good, and reading can be performed at high speed. Therefore, it is not necessary to use a plurality of semiconductor lasers and assign each semiconductor laser to a different area on the surface of a radiation image information recording medium such as a radiation image conversion panel in order to increase the reading speed. The time required to read the information recording medium surface can be shortened.

Further, according to the present invention, since a single integrated semiconductor laser is used as a laser light source, the entire device can be made smaller and lower in cost, and various other excellent effects can be achieved.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which FIG. 1 is a schematic perspective view of the whole, FIG. 2 is a sectional view of a light source, FIG. 3 is a partially cutaway perspective view of an integrated semiconductor laser with a multi-stripe structure, and FIG. Figure 4 is v
FIG. 2 is a cross-sectional view of an integrated semiconductor laser having an SRS structure. l...Integrated semiconductor laser light source 2 - Laser beam deflection means 3 - Sub-scanning means 4 - Radiation image conversion panel (radiation image information recording medium) 5 - Stimulated luminescence condenser patent Applicant Roku Konishi Photography Industrial Co., Ltd. f

Claims (3)

[Claims] (1) an integrated semiconductor laser light source; a laser beam deflection means for linearly irradiating the laser light emitted from the integrated semiconductor laser light source onto the surface of a radiation image information recording medium; A radiation image reading device characterized by comprising a sub-scanning device that moves the irradiated laser beam relatively in a direction substantially perpendicular to the irradiated laser beam. (2) The radiation image reading device according to claim 1, wherein the integrated semiconductor laser is of a phase-locked type. (3) The radiation image reading device according to claim 2, wherein the phase-locked integrated semiconductor laser provides a unimodal far-field image.