JPH0328800A - Production of radiograph converter - Google Patents

Abstract

PURPOSE:To decrease the roggedness on a surface and to improve the resolution of read images by forming a phosphor layer contg. a stimulable phosphor, then polishing the front surface (and rear surface) of the phosphor layer to flatten the layer. CONSTITUTION:A paint contg. the stimulable phosphor is first applied on a film 11 consisting of, for example, polyethylene terephthalate at about 250Xm thickness by using a doctor blade and is then dried to form the phosphor layer 1. The phosphor layer 1 imposed on a base 21 is press welded with a tape 22 with a polishing material on the surface thereof by means of a pressing roller 23. The tape 22 and the phosphor layer 1 are rubbed against each other by rotating the roller 23 at this time to polish the surface of the phosphor layer 1.The ruggedness is formed on the rear surface as well in some case. The film 11 is removed and the rear surface side thereof is polished as well in such a case.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a method for converting a radiation image converter containing a stimulable phosphor, with the aim of improving the resolution of image reading by laser irradiation. The surface (and back surface) of the phosphor layer is polished to make it flat.

(Industrial Application Field) The present invention relates to a method for producing a radiation image converter using a stimulable phosphor.

In the medical industry, X-ray image converters using stimulable phosphors are used as part of digital X-ray diagnostic systems.
There are systems that accumulate line images and read them with a laser.

In the case of this system, image reading resolution is an important issue because it is used for human medical treatment.
It is desirable to increase this resolution.

}One branch of Juto] The radiation image converting body is the 12-light body of the eye with Hikari Jmata 1.
! J: There is one made by drying and forming a stimulable phosphor and then sintering a stimulable phosphor.

Fig. 6 14 explains the conventional JJ da 8/1 line image converter]
3-l in the cross-sectional diagram, 1 is the phosphor layer, 2 is the supporting substrate, 3
He has skipped the 2nd and 7th lessons.

Conventional radiation image converters include a barrier 1 containing a stimulable phosphor.
(Lining cloth. Plane dry, bite is photostimulable hez light body {A
The light emitting layer formed by cutting the frame 7] is the support 1, ~substrate 2-1-
Glue ζ 2 and finish the structure with a protective film 3 on its surface 7 .

(If the invention is sold 7.) Dosing problem] 14. Coating the stimulable phosphor, drying, or [Yoki 1-.
'i L If the state remains as it is, is the front surface of phosphor layer 1? 1-2 // m for the coated and dried type, up to 2 f'. for the sintered type. ) 7/ m concave + L.
I+ or L f-;

For this reason, after foiling both the X-ray images of the 1st and 1st-ray image converting body Z, this is transferred to the 1st-ray conductor L-- for example.
, when reading it as shown in Figure J,
11, ((The emitted beam A is 31'!Light layer 10) 116 disordered by ljlI1.!+(A) on the back side.!
'1. ``■Deshima・） is a Japanese example of Germany.

When the laser beam is scattered, the scattered light continues and becomes noise compared to the light. The problem of F' 1 arises.

In particular, if you increase the particle size of the Fl-like powder-like phosphor that increases the sensitivity of the radiation image converter, then Due to the size of fH, (1-1) the gate 1111 on the front surface is thick.
Me, [, - The Sea 1a T7) lit? ;The problem is that t is the same as the earth.

The present invention reduces the front curve 1111 of the J-line image converter by 1jHlj to increase the resolution of the read image by liiJ-L
'J-Rugoto 4 [I assume.

? 1 step to determine iW of B] After forming a phosphor layer containing 17 photons and 12 photons, Masaaki Moto et al. ) jiltlX:? Seikomi-no-J that includes a succulent and juicy king culm
According to the law, please refer to ``Achieve the first goal 4)''.

? 1′l river] The present invention ε:L. ii! The surface of the light layer is made with a concave surface (111 is polished 14'1), and the surface of the surface is made smooth.

Shinogoka-,-(,,l/-the!! I was able to suppress the image of the 11th line in high resolution and take it as a blasphemy.
? 1.

! 1I + Otsuko, 11I Use a large phosphor with a diameter of 11I to increase the sensitivity to 1: riI-゛4. (-.i (Jinkyoku no Mon II.I
＋力悄'+'
! ．． degree can be obtained.

? Example] Figure 1: Explaining the first example of the present invention-1
4H [H cross section is j.

Figure 1 (, 1) Board illumination point 3゛, example λ Bori: L Chiren U L/Ivy L. / −
．． ．． 1. On the film 11, a coat containing the phosphor is poured into the film 11.
5] 0) i m Q] IAI SO ('Q After cloth, dry it and shape it into 1it photolayer 1.

l-marking 1'l L. l, phosphor outside the bright bottle and ゛(shamekaseihahariu l, / .71- ..- +: +bi 1゛nom (13 rh CI r{ r: }i u)
500 g, polymethyl notakuri L/-1 (PMMA) as a binder (powder mixture) 50 g. Combine 30 g of I''J plasticizer and ζ Sozo → Luftale 1, and 200 g of solvent - (1.
Put it in 74ζ-ノI-:', le (71L training permit).
-kL view Illj Tsumugi L thing (see the 6th figure t (+3).
For example, l 4 'X l f; +jlJ to the size of inches
Then, polish the back side.

FIG. 2 shows a schematic structure of the polishing apparatus.

The phosphor layer 1 placed on the support base 21 has an abrasive tape 22 pressed onto its surface by a pressure roller 236. By rotating the tape 22 and the phosphor layer 1, the surface of the phosphor layer 1 is polished.

In this case, the grain size of the abrasive material (Altananato) of the tape 22 is 5 μm, 1 μm. 0.5 μm ones were prepared and polished by replacing them in this order.

- On the other hand, if only the surface of the phosphor layer 1 is polished in this way, unevenness may be formed on the black surface as well, so in that case, remove the film 11 and polish the back side as well. .

In the wooden example, the surface roughness was 0.1 μm as a result of the above polishing.
The following phosphor layer 1 could be obtained.

Refer to FIG. 1(c) After the polished phosphor layer 1 is adhered onto the support substrate 2, a protective film 3 is formed on the surface thereof.

A glass substrate is used as the supporting plate 2, and as the protective film 3, for example, a polyethylene terephthalate film 1 with an ITO (InSn oxide) film is used.

Microphone 11 Jar 1 is attached to the radiation image converter according to this embodiment.
- (Resolution Inspection Sheet) is placed, irradiated with X-rays of 80KV peak value and accumulated X-ray images, then 780nm
When irradiated with a laser having a wavelength of , the resolution of a conventional radiation image converter was 180 μm, but in this example, a resolution of 150 μm could be obtained.

This is a 20% increase in resolution compared to the conventional method.

FIG. 3 is a process sectional view illustrating a second embodiment of the present invention.

Figure 3 (a) Reference II <( First, the phosphor layer 1 is formed by sintering the stimulable phosphor.

The phosphor layer l is formed by the following steps.

First, barium chloride (B a C I 2) was added to 123.
6 g of halium bromide (BaBrz), 176.4 g of eurobium bromide, and 0.184 g of eurobium bromide were weighed and mixed in a ball mill, then placed in a quartz boat and calcined in air at 600°C for 2 hours.

Next, this was crushed in an agate mortar for 1 hour, and 30.0 g of acrylic resin, 20.0 g of dibutyl phthalate as a plasticizer, and 122.4 g of 1.luene were added.
Ball mill mixing was carried out for 5 hours using an agate bong and pole.

Next, this is placed in a polyethylene beaker, degassed under vacuum, and then coated onto a polyethylene terephthalate sheet using a doctor blade to a thickness of about 300 μm.

This was cut into 450 mm x 450 mm, peeled off from the above sheet and placed on a quartz plate, placed in an electric furnace and gradually heated in air to 600 mm.
'C for 5 hours to evaporate the organic binder.

Finally, this was heated at 8oO°C in a hydrogen + helium atmosphere.
The phosphor layer 1 is obtained by sintering for 2 hours.

Refer to FIG. 3(b) The phosphor layer 1 was polished using the polishing apparatus shown in FIG. The surface roughness was 0.5 μrn, which was the maximum of 20 μrn.
It became less than μm.

Refer to FIG. 3(c) After cutting the flattened phosphor layer 1 into 352 x 352 mm, it is adhered to a glass supporting substrate 2 with an epoxy resin 4 and its surface is coated at the same time. A protective film 3 made of polyethylene terephthalate on which a thin oxide film was formed was formed.

Test rice of the radiation image converter according to this example and phosphor layer 1
A sample of an unpolished radio-1/1-ray image converter is prepared, and X-rays (80 kV) are applied to both of them at approximately 5ξ.
After irradiating the entire surface with Relene 1 Gen, 780 nm was applied to both sides.
The laser beam was scanned, and the generated stimulated luminescence was converted into electricity. FIG. 4 shows the photoelectrically converted voltage waveform.

In the sample that has not been subjected to the polishing process, as shown in FIG. 4(b), a certain amount of noise contained in the successive waveforms appears significantly.

On the other hand, in the sample according to this example, as shown in FIG. 4(a), the noise level is reduced and a substantially constant continuous voltage is obtained.

In addition, as another comparative example, a tungsten grid was placed on the panel of the two samples described above, and reading was performed by irradiating X-rays.

At that time, the interval between the grids is gradually narrowed to increase the modulation tra
nsferfunction). Figure 5 shows the results.

As is clear from FIG. 5, the MTF of the sample according to this example
(A) is the MTF (
B) was observed to be more elongated.

[Effects of the Invention] As explained above, since the radiation image converting body according to the present invention has a flattened surface, there is no surface disturbance of the readout laser, and variations in the amount of light emitted from the phosphor are reduced. Noise is reduced.

As a result, it is possible to improve reading efficiency and resolution, and obtain highly accurate radiation images. iJ- is possible.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining a first embodiment of the present invention, FIG. 2 is a diagram showing a schematic structure of a polishing apparatus, and FIG. 3 is a diagram illustrating a second embodiment of the present invention.
FIG. 4 and FIG. 5 are diagrams explaining the effects of the embodiment, and FIG. 6 is a diagram explaining the conventional technique. In the figure, (1)...phosphor layer 2...support substrate 3...protective film. 12 dwing -) v1 prefecture

Claims (4)

[Claims] (1) forming a phosphor layer containing a stimulable phosphor;
A method for manufacturing a radiation image converter, comprising: polishing and flattening the surface of the phosphor layer. The method for manufacturing a radiation image converter according to claim 1, further comprising the step of (2) polishing the back surface of the phosphor layer. (3) The phosphor layer is comprised of a coating sheet formed by applying a paint containing a stimulable phosphor to the surface of a film and drying it. A method for producing a radiation image converting body. (4) Claim (1) or (4) characterized in that the phosphor layer is formed by sintering a stimulable phosphor.
2) A method for producing a radiation image converter as described above.