JP2003270394A - Stimulable phosphor panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heighten the quality of an image signal for showing a radiogram acquired by detection of accelerated phosphorescence emitted light generated from a stimulable phosphor layer in a stimulable phosphor panel. <P>SOLUTION: The stimulable phosphor layer 10 and a light convergent layer 20 are laminated so that the stimulable phosphor layer 10 and the light convergent layer 20 equipped with a plurality of micro-prisms 21, for converging and passing a beam of the accelerated phosphorescence emitted light generated from the stimulable phosphor layer 10 are brought into contact with each other through physical contact points P dispersed uniformly, and that a gas layer 30 is formed between the stimulable phosphor layer 10 and the light convergent layer 20. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stimulable phosphor panel, and more specifically, to a stimulable phosphor layer and a light converging layer for converging and passing the luminous flux of stimulated emission light generated from the stimulable phosphor layer. And a stimulable phosphor panel comprising:

[0002]

2. Description of the Related Art Conventionally, when radiation such as X-rays is irradiated, a part of this radiation energy is accumulated, and when excitation light such as visible light is then irradiated, stimulated emission is shown according to the accumulated radiation energy. By using a stimulable phosphor (stimulable phosphor), a radiation image of a subject such as a human body is once recorded as a latent image in the stimulable phosphor layer, and an excitation light such as a laser beam is radiated on the stimulable phosphor layer. Radiation image recording including a radiation image recording device and a radiation image reading device for irradiating a laser beam to generate stimulated emission light and photoelectrically detecting the stimulated emission light to obtain an image signal representing a radiation image of a subject. Playback system is CR
(Computed Radiography).

As a recording medium used in the radiation image recording / reproducing system, a stimulable phosphor layer is laminated on the protective layer by coating or vapor deposition, and the stimulable phosphor layer and the protective layer are laminated. There is known a stimulable phosphor panel that is formed so that the entire laminated area is in physical contact.

Further, instead of the protective layer, a light converging layer for converging and passing the luminous flux of the stimulated emission light generated from the stimulable phosphor layer is laminated on the stimulable phosphor layer, thereby stimulating the stimulable luminescent light. There is also known a stimulable phosphor panel in which the detection efficiency of (1) is increased (Japanese Patent Laid-Open No. 2001-208899). Furthermore, a gas layer is formed between the stimulable phosphor layer and the light converging layer by laminating the stimulable phosphor layer and the light converging layer via a spacer, and the photostimulation generated from the stimulable phosphor layer is formed. By making the emitted light enter the light converging layer having a higher refractive index than the gas layer through the gas layer, the spread of the luminous flux of the stimulated emission light propagating in the light converging layer is narrowed, and the light emitted from the light converging layer is emitted. A stimulable phosphor panel in which the luminous flux of the exhaust emission light is further converged so that the detection efficiency of the stimulated emission light is further enhanced is also under study.

[0005]

However, in forming the above-mentioned stimulable phosphor panel in which a gas layer is formed between the stimulable phosphor layer and the protective layer, the peripheral portion of the stimulable phosphor layer is formed. When a spacer is arranged only on the storage layer, that is, when the spacing (pitch) between the spacers is expanded to remove the radiation image reading region on the stimulable phosphor layer and the light converging layer is laminated on the stimulable phosphor layer. Since the light converging layer is bent by its own weight and a region where the stimulable phosphor layer and the light converging layer come into contact with each other is generated, a thick spacer is arranged to increase the distance between the stimulable phosphor and the light converging layer. In the region where the distance between the light converging layer and the stimulable phosphor layer is widened in this way, the excitation light incident on the stimulable phosphor layer is Accumulated by being repeatedly reflected between the layer and the light converging layer Irradiation region to the excitation light of the phosphor layer will spread.

That is, when the distance between the light converging layer and the stimulable phosphor layer is wide, the propagation distance of the excitation light in one reflection is long, so that as shown in FIG.
And excitation light Le which is incident through the gas layer 30 and is repeatedly reflected between the light converging layer 20 and the stimulable phosphor layer 10.
Spread in the range of the region R1 on the stimulable phosphor layer 10.
On the other hand, when the distance between the light converging layer 20 and the stimulable phosphor layer 10 is narrow, the propagation distance of the excitation light in one reflection is short as shown in FIG. 21, and therefore the light converging layer 20 and the gas layer 30. The excitation light Le that has been incident through and is repeatedly reflected between the light converging layer 20 and the stimulable phosphor layer 10 spreads in a region R2 narrower than the region R1. Therefore, even if the excitation light is reflected the same number of times between the light converging layer 20 and the stimulable phosphor layer 10, the irradiation region of the excitation light is widened when the distance between the two is wide.

Therefore, the stimulable phosphor layer 10 emits stimulated emission light by the same action as that when it is irradiated with the excitation light having a thick luminous flux corresponding to the wide region R1 and is out of this detection range. There is a problem that the sharpness of the radiation image represented by the image signal acquired by detecting the stimulated emission light generated from a wide area including the above-mentioned deteriorates.

Further, the pitch of the spacers is narrowed, a large number of thin spacers are arranged in a region for detecting a radiation image on the stimulable phosphor layer, and the light converging layer is provided on the stimulable phosphor layer through these spacers. When a layer is laminated, a thin gas layer having a uniform thickness is formed between the stimulable phosphor layer and the light converging layer, so that the expansion of the irradiation region of the excitation light is suppressed, but on the stimulable phosphor. The arranged spacers scatter or block the excitation light incident on the stimulable phosphor layer, and also scatter or block the stimulated emission light generated from the stimulable phosphor layer. However, there is a problem in that the radiation image represented by the image signal acquired by detecting such stimulated emission light has uneven image quality.

The present invention has been made in view of the above circumstances, and it is possible to improve the quality of an image signal representing a radiation image obtained by detecting stimulated emission light generated from a stimulable phosphor layer. The purpose of the present invention is to provide a fluorescent phosphor panel.

[0010]

The stimulable phosphor panel of the present invention comprises a stimulable phosphor layer, and a stimulable phosphor layer laminated on the stimulable phosphor layer, which is irradiated with excitation light. Is a stimulable phosphor panel comprising a light converging layer that converges and passes the luminous flux of stimulated emission light generated from the stimulable luminescent light, wherein the stimulable phosphor layer and the light converging layer are physically dispersed. It is characterized in that a gas layer is formed between the stimulable phosphor layer and the light converging layer by being brought into contact with each other via a contact point.

The value of the ratio R of the area occupied by the contact points to the area of the laminated region in which the stimulable phosphor layer and the light converging layer are laminated is preferably 0 <R ≦ 30%.

The light converging layer may be formed by arranging a plurality of microlenses in a plane.

The light converging layer has a thickness of 1 μm or more and 100 μm.
m or less, and the microlenses have a pitch of 50μ.
It may be arranged in parallel at a distance of m or less. When the microlenses are formed on the base material, the light converging layer includes the base material and the microlenses arranged side by side on the base material.

The light converging layer may be a resin film having surface irregularities.

The physical contact point means a point where two objects are physically in direct contact with each other without interposing a solid, a gas, a liquid or the like. That is, for example, when two objects having roughness on the surface are stacked on each other, a region adjacent to each other through a gas layer in the stacked region and a direct contact with each other without interposing the gas layer The area that is in direct contact at this time is the physical contact point.

Further, to uniformly disperse the physical contact points means that the physical contact points of the physical contact points are added to the radiation image represented by the image signal obtained by detecting the stimulated emission light generated from the stimulable phosphor layer. This means that the physical contact points are arranged without any deviation so that the unevenness of the image quality due to the presence does not occur.

[0017]

According to the stimulable phosphor panel of the present invention,
Since the stimulable phosphor layer and the light converging layer are brought into contact with each other through the evenly distributed physical contact points, a gas layer is formed between the stimulable phosphor layer and the light converging layer. The quality of the image signal representing the radiation image obtained by detecting the stimulated emission light generated from the stimulable phosphor layer can be improved. That is, the physical contact point dispersedly arranged between the stimulable phosphor layer and the light converging layer is the point where the stimulable phosphor layer and the light converging layer are in direct contact, and the excitation light is This excitation light is not scattered or blocked by the physical contact point before reaching the body layer, and the stimulated emission light generated from the stimulable phosphor layer is scattered or blocked by the physical contact point. It will not be done. Further, in the region other than the physical contact point in the laminated region where the stimulable phosphor layer and the light converging layer are laminated, the stimulable phosphor layer and the light converging layer are arranged close to each other through a thin gas layer. Therefore, the spread of the excitation light irradiation region on the stimulable phosphor layer can be reduced. With these, the quality of the image signal representing the radiation image obtained by detecting the stimulated emission light generated from the stimulable phosphor layer can be improved.

Further, if the value of the ratio R of the area occupied by the physical contact points to the area of the laminated region where the stimulable phosphor layer and the light converging layer are laminated is 0 <R ≦ 30%, the gas By emitting the stimulated emission light through the layer, the spread of the luminous flux of the stimulated emission light can be suppressed to be small, and the light collection efficiency of the stimulated emission light can be sufficiently increased. That is, since the refractive index of the gas layer is 1.0, the value of the ratio R is 0 <R ≦ 30.
%, The average refractive index of the entire layered boundary region including the gas layer and the physical contact point sandwiched between the stimulable phosphor layer and the light converging layer is 1.2 or less. However, since there is substantially no substance having a refractive index of 1.2 or less in the solid or liquid state, the entire layered boundary region is filled with the solid or liquid so that the refractive index is 1. It is virtually impossible to set it to 2 or less. Therefore, if the value of the ratio R is 0 <R ≦ 30%, the efficiency of collecting stimulated emission light can be sufficiently increased by passing through the gas layer.

Here, if the light converging layer is formed by arranging a plurality of microlenses in a plane, the luminous flux of stimulated emission light passing through the light converging layer can be reliably converged, and It is possible to more reliably obtain the effect of increasing the efficiency of collecting exhausted light. Furthermore, the light converging layer has a thickness of 1 μm or more,
If the microlenses are 100 μm or less and the microlenses are arranged in parallel at a pitch of 50 μm or less, the pitch of the microlenses is formed by converging stimulated emission light generated from the stimulable phosphor layer by each microlens. It is possible to more reliably disperse the light amount unevenness of the stimulated emission light that occurs in accordance with the above, and it is possible to further reduce the unevenness of the image quality of the radiation image represented by the image signal acquired by the detection of this stimulated emission light. In addition, an effect of facilitating stacking of the light converging layer on the stimulable phosphor layer by setting the thickness of the light converging layer to 1 μm or more, and blurring of a radiation image by setting the thickness to 100 μm or less. The effect of suppressing can be obtained.

That is, when the thickness of the light converging layer is less than 1 μm, when the light converging layer is laminated on the stimulable phosphor layer, the light converging layer is wrinkled, and so on. It becomes difficult to stack the above-mentioned light converging layer on the above. On the other hand, when the thickness of the light converging layer is larger than 100 μm, as shown in FIG. 22, the stimulable phosphor of the excitation light Le or the stimulated emission light K reflected at the interface Q between the light converging layer 20 and the outside air A is accumulated. Layer 1
Since the propagation distance R3 of the return light to 0 in one reflection becomes long, the excitation light Le or the stimulated emission light K reflected between the interface Q and the stimulable phosphor layer 10 is the stimulable fluorescence. The radiation image is spread over a wide range on the body layer 10 and the blur of the radiation image represented by the image signal acquired by the detection of the stimulated emission light increases.

If the light converging layer is a resin film having surface irregularities, the light converging layer can be formed more easily.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view showing a schematic configuration of a stimulable phosphor panel according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the stimulable phosphor panel, and FIG. 3 is a stimulable phosphor panel through a gas layer. FIG. 4 is a diagram showing the spread of the luminous flux of stimulated emission light emitted from the device, FIG. 4 is a diagram showing the spread of the luminous flux of stimulated emission light emitted from the stimulable phosphor panel without passing through the gas layer, and FIG. Conceptual diagram comparing the area of the region occupied by the gas layer and the area of the region occupied by the physical contact point in the laminated region of the fluorescent layer and the light converging layer. FIG. 6 corresponds to one pixel of the radiation image. FIG. 7 is a conceptual diagram showing a microlens in the light converging layer arranged, FIG. 7 is a diagram showing the directivity of stimulated emission light emitted through the light converging layer, and FIG. 8 is a light converging light having a coating layer for antireflection. Cross-sectional view of the side surface of the layer, FIG. 9 (a) to 9 (d) is like a microlens Perspective view showing the shape, FIG. 10 is a sectional view showing a side surface of the stimulable phosphor panel formed by bonding through a low refractive index adhesive and stimulable phosphor layer and the light converging layer.

The stimulable phosphor panel according to the embodiment of the present invention is laminated on the stimulable phosphor layer 10 and the stimulable phosphor layer 10, and is irradiated with excitation light to receive the stimulable phosphor layer 10.
And a light converging layer 20 for converging and passing the luminous flux of stimulated emission light generated from the stimulable phosphor layer 10 and the light converging layer 20 via physical contact points P evenly dispersed. Are brought into contact with each other to form a gas layer 30 between the stimulable phosphor layer 10 and the light converging layer 20.

The physical contact point P with respect to the area of the laminated region where the stimulable phosphor layer 10 and the light converging layer 20 are laminated.
The value of the physical contact ratio R, which is the ratio of the area occupied by
%. The light converging layer 20 is formed by arranging a plurality of microlenses 21 in a plane, and each of the microlenses 21 arranged in parallel is a stimulable phosphor layer 10.
The incident surface 22 on the side on which the stimulated emission light generated from is incident is a flat surface, and the emission surface 23 on the side on which the stimulated emission light is emitted is a spherical lens.

Next, the operation of the above embodiment will be described.

The stimulated emission light generated from the stimulable phosphor layer 10 in response to the irradiation of the excitation light incident from the outside through the light converging layer 20 propagates through the light converging layer 20 and forms a spherical exit surface 23. Is refracted at the boundary between the air and the outside air A, and the light flux is converged and emitted. An image signal representing the radiation image recorded in the stimulable phosphor layer 10 is obtained by detecting the stimulated emission light emitted from the light converging layer 20. By scanning the two-dimensional area on the stimulable phosphor layer 10 with the excitation light, the stimulated emission light generated from this two-dimensional area is detected, and the two-dimensional area representing the radiation image is detected. The image signal of is acquired.

Here, a case where stimulated emission light generated from the stimulable phosphor layer 10 is incident on the light converging layer 20 through the gas layer 30 and detected, and a case where the stimulable phosphor layer 10 physically exists. The case where the stimulated emission light generated from the contact point P is directly incident on the light converging layer 20 and detected without passing through the gas layer 30 will be described in detail.

The effect that the luminous flux of the stimulated emission light propagating through the light converging layer 20 is refracted and converged at the exit surface 23 of each microlens 21 has the effect of passing through the gas layer 30.
This is the same for the stimulated emission light propagating through the inside and for the stimulated emission light propagating in the light converging layer 20 generated from the physical contact point P, and therefore a spherical surface is used in the following description. Excluding the exit surface 23 from the light converging layer 20, the light converging layer is regarded as a parallel plate, and the stimulated emission light propagated through the gas layer 30 and the stimulated emission light generated from the physical contact point P and propagated. I will explain the difference in the optical path.

When the stimulated emission light generated from the stimulable phosphor layer 10 is detected through the gas layer 30, it is generated from the stimulable phosphor layer 10 and is incident on the gas layer 30, as shown in FIG. The stimulated emission light K1 is refracted at the boundary between the gas layer 30 having a low refractive index and the parallel plate layer 20A having a higher refractive index than the gas layer 30, and the light flux is once converged, and then the parallel plate layer 20A and the refractive index. At the boundary with the outside air A having a low temperature, the light beam is refracted again in the direction in which the light beam diverges, and is emitted from the parallel plate layer 20A at an exit angle α
It is fired at 1. The parallel plate layer 20A is formed by removing the light exit layer 23, which is a spherical surface, from the light converging layer 20 to form a parallel plate.

On the other hand, as shown in FIG. 4, when the stimulated emission light is emitted from the physical contact point P and enters the parallel flat plate layer 20A without passing through the gas layer 30, the stimulable phosphor layer is formed. The stimulated emission light K2 generated from the light beam 10 directly enters the parallel plate layer 20A without being refracted, and is refracted in the direction in which the optical path diverges at the boundary between the parallel plate layer 20A and the outside air A having a low refractive index and the exit angle. It is ejected at α2 (α2> α1).

Therefore, by propagating the stimulated emission light through the gas layer 30, it is possible to reduce the spread of the luminous flux of the stimulated emission light emitted from the parallel plate layer 20A.

When the stimulated emission light is emitted from the physical contact point P, the effect of converging the luminous flux of the stimulated emission light cannot be obtained by passing through the gas layer 30. The physical contact point P does not block or scatter the excitation light as in the case where the spacer is interposed between the stimulable phosphor layer and the light converging layer, and does not generate stimulated emission light. It does not interfere with the propagation. Further, since the physical contact points P are evenly distributed between the stimulable phosphor layer 10 and the parallel flat plate layer 20A, the spread of the luminous flux of stimulated emission light caused by the presence or absence of the physical contact points. The unevenness of the detected intensity of the stimulated emission light due to the difference is mitigated, and the unevenness of the quality of the radiation image represented by the image signal acquired by the detection of the stimulated emission light can be suppressed.

When the value of the physical contact ratio R is 30%, the stimulated emission light is emitted from the physical contact point P without passing through the gas layer 30, as shown in FIG. The region 11 is 30% of the stimulable phosphor layer 10, and the region 12 from which stimulated emission light is emitted through the gas layer 30 having a refractive index of 1 is 70% of the stimulable phosphor layer 10. Area. Then, the region 1 including the physical contact point P in the layered boundary region 31 including the gas layer 30 and the physical contact point P.
If the average refractive index of 1 is 1.7, the layered boundary region 31
The average refractive index as a whole is 1.21 (1.21 =
(1.7 × 30% + 1.0 × 70%) / 100%). Here, since a layer having a refractive index of 1.21 or less cannot be considered substantially other than a gas layer, setting the value of the physical contact ratio R to 30% is sufficient to enhance the detection efficiency of stimulated emission light. The effect can be obtained. The above-mentioned refractive index means the refractive index with respect to the wavelength of the stimulated emission light.

Further, by using the parallel plate layer 20A as the light converging layer 20 in which the exit surface 23 having a lens function is added to the parallel plate layer 20A, the stimulated emission light emitted through the light converging layer 20. Is more converged by passing through each microlens 21, and can be emitted from the light converging layer 20 with stronger directivity in a direction perpendicular to each layer surface laminated in the stimulable phosphor panel. .

That is, as shown in FIG. 6 and FIG.
Storage phosphor layer 10 corresponding to one pixel G representing a radiation image
The directivity ε1 of the stimulated emission light emitted through the plurality of microlenses 21 arranged corresponding to the upper region is
It is possible to eliminate the spherical emission surface 23 from the light converging layer 20 and make it higher than the directivity ε2 of the stimulated emission light emitted when this light converging layer is a parallel plate.

Here, as shown in FIG. 8, the light converging layer 20 is formed.
However, a coating layer 25 having a lower refractive index than the light converging layer 20 may be provided on the light converging layer 20 side of the stimulable phosphor layer 10. As a result, it is possible to reduce the amount of reflected light of the repeated reflection of the excitation light generated between the light converging layer 20 and the stimulable phosphor layer 10 by the excitation light radiated from the outside, and to the stimulable phosphor layer. The irradiation area of the excitation light can be reduced substantially.

In the above embodiment, the value of the physical contact ratio R is 30%, but if the value of the physical contact ratio R is in the range of 0 <R ≦ 30%, the gas layer is formed. It goes without saying that the effects of doing this can be obtained.

In the above-described embodiment, the microlenses in the light converging layer have been described as examples in which the incident side of the stimulated emission light is a flat surface and the exit side is a spherical surface. May be on both sides of the incident side and the exit side of the stimulated emission light, or only on one side of the incident side, and as the microlens, lenticular lenses arranged side by side in one direction as shown in FIG. 9 (a)), triangular prisms arranged in one direction (see FIG. 9 (b)), and two-dimensionally arranged pyramidal prisms (see FIG. 9 (c)) and two-dimensional shape. It is also possible to employ a hemispherical lens (see FIG. 9 (d)) or the like arranged in the. In addition,
The pitch of the microlenses does not necessarily need to be 50 μm or less, and a plurality of microlenses may be arranged corresponding to a region corresponding to one pixel when acquiring an image signal representing a radiation image. . In addition, the light converging layer,
It may be formed of a resin film having surface irregularities, and the surface irregularities may have a lens function of converging stimulated emission light.

Further, as shown in FIG. 10, the stimulable phosphor layer 10 and the light converging layer 20 may be adhered to each other via an adhesive having a refractive index lower than that of the light converging layer. in this case,
The stimulated emission light generated from the stimulable phosphor layer 10 is applied to the adhesive portion 3
The light flux of the stimulated emission light is emitted in the same manner as described above, because the light flux is emitted into the optical fiber 5 and is refracted in the direction in which the light flux converges at the boundary 26 between the adhesive portion 35 and the light converging layer 20 having a higher refractive index than the adhesive portion 35. It is possible to obtain the effect of more converging. Since the adhesive portion 35 has a higher refractive index than the gas layer having a refractive index of about 1, the effect of converging the luminous flux of the stimulated emission light is greater than that of converging the stimulated emission light through the gas layer. Decrease.

Further, since the light converging layer has the above-mentioned microlens, it has a complicated surface shape, and the excitation light incident from the outside may be scattered inside the light converging layer. Therefore, a coloring layer or a scattering layer for attenuating the scattering may be provided in the light converging layer.

Furthermore, the area of each physical contact point is set to 1
If it is 000 μm ² or less, the unevenness of the detected intensity of the stimulated emission light caused by the difference in the spread of the luminous flux of the stimulated emission light caused by the presence or absence of the physical contact point is alleviated, and this stimulated emission light It is possible to further reduce the unevenness in the quality of the radiation image represented by the image signal acquired by the detection.

The experimental results using the stimulable phosphor panel according to the above invention will be described below. 11 is a cross-sectional view showing a schematic configuration of the stimulable phosphor panel of Example 1, FIG.
2 is a perspective view showing a schematic configuration of the stimulable phosphor panel of Example 2, FIG. 13 is a sectional view showing a schematic configuration of a stimulable phosphor panel of Comparative Example 1, and FIG. 14 is a stimulable phosphor of Comparative Example 2. It is sectional drawing which shows schematic structure of a panel.

1. Formation of stimulable phosphor panel for experiments [Example 1] A tetrahedral phosphor (BaFBr0.85I0.15: Eu2 +) having an average particle diameter Dm = 4.5 μm is shown below.

[Binder] and methyl ethyl ketone were dispersed to prepare a coating liquid, which was coated on a polyethylene terephthalate support with a doctor blade to form a phosphor layer having a thickness of 300 μm. The weight ratio of phosphor to binder is 1:20.

○

[Binder] (Binder composition): (Note that the following numbers are based on the weight of all binders as 100.)-Polyurethane elastomer 70 parts by weight-Crosslinker (polyisocyanate) 10 parts by weight-Yellow Tamperproof agent 20 parts by weight

A light-converging film 54 shown in FIG. 11 is prepared by preparing a [coating liquid] and coating and coating it on a smooth polyethylene terephthalate (PET) having a thickness of 6 μm with a bar coder.
Got the composition of.

○

[Coating liquid]

・ 8 parts by weight of 5μm cross-linked acrylic monodisperse particles (Chemisno-MX500, manufactured by Soken Chemical Co., Ltd .: Refractive index = 1.51) ・ 26 parts by weight of PVA resin aqueous solution (8 wt% concentration: PVA217, manufactured by Kuraray Co., Ltd .: refraction) 66% by weight of water This was laminated on the surface of the phosphor layer without using a glue layer and the periphery was fixed with glue to form a stimulable phosphor panel 91 shown in FIG. 11.

The symbols in FIG. 11 indicate the following.

51: Cross-linked acrylic monodisperse particles (φ 5 μm) 52: PVA resin film (thickness 2 μm) 53: PET film layer (thickness 6 μm) 54: Light converging film 55: Air layer 56: Phosphor layer 57: Fluorescence Body particles P1: Microlens pitch = 5 μm H1: Microlens height = 11 μm [Example 2] A PVA resin film having prism shapes arranged in parallel as shown in FIG. A stimulable phosphor panel 92 was formed by stacking the same on the fluorescent layer 56.

The symbols in FIG. 12 indicate the following.

58: PVA resin film (having a prism shape) 55: air layer 56: phosphor layer 57: phosphor particles P2: microlens pitch = 20 μm H2: microlens height = 35 μm [Comparative Example 1] The same phosphor layer 56 as in Example 1 was formed by using a smooth polyethylene tereflut (PET) film having a thickness of 6 μm.
A stimulable phosphor panel 93 was formed by stacking on top (see schematic FIG. 13).

The symbols in FIG. 13 indicate the following.

59: Smooth PET resin film (thickness 6 μm) 55: Air layer 56: Phosphor layer 57: Phosphor particles [Comparative Example 2] The light converging film 54 of Example 1 was used for the same fluorescence as that of Example 1. A polyester resin glue layer (thickness = 1.
5 μm: final folding rate = 1.53) and laminated to form a stimulable phosphor panel 94 (see schematic FIG. 14).

The symbols in FIG. 14 indicate the following.

51: Cross-linked acrylic monodisperse particles (φ 5 μm) 52: PVA resin film (thickness 2 μm) 53: PET film layer (thickness 6 μm) 54: Light converging film 60: Glue layer (thickness 1.5 μm) 56: Phosphor layer 57: Phosphor particles P1: Microlens pitch = 5 μm H1: Microlens height = 11 μm 2. Evaluation Hereinafter, evaluation of the stimulable phosphor panel for the above experiment will be described. FIG. 15 is a conceptual diagram showing a schematic configuration of the evaluation device,
FIG. 16 is a diagram showing the measurement result of the light emission angle distribution, FIG.
Is a diagram showing an emission angle distribution of stimulated emission light generated from the stimulable phosphor panel, and FIG. 18 is a conceptual diagram showing a schematic configuration of a stimulated emission light detection device.

As shown in FIG. 15, the excitation light Le is emitted from the laser 65, and the excitation light Le is irradiated on an arc centered on the point E on the stimulable phosphor panel (91 to 94).
Using an evaluation device 67 in which six photomultipliers M1 to M6 are arranged at 15 ° intervals, stimulated emission light K generated from point E on the storage phosphor panel (91 to 94) irradiated with excitation light. Was received by the photomultipliers M1 to M6 arranged at each of the above angles, and integrated for a certain period of time to measure the integrated intensity. In addition, the four samples of the stimulable phosphor panels 91 to 94 for the above experiment were preliminarily given a fixed dose of X
I had bombed the line.

Photomultiplier M arranged at 0 °
The cumulative intensity of the stimulated emission light measured by 1 is 1,
Table 1 and FIG. 16 show the measurement results of the emission angle distribution obtained from the intensity ratio between the integrated intensity at 0 ° and the integrated intensity of photostimulated luminescent light measured by the photomultipliers M1 to M6 arranged at respective angles. Shown in.

[0056]

[Table 1] Generally, in a normal diffuser such as phosphor powder, the relationship between the angle and the intensity ratio should be a cos θ distribution.
The luminous angle distribution of the stimulable phosphor panel 93 of Comparative Example 1 in which the smooth PET film 59 is laminated on the phosphor layer 56 is cos
The distribution is close to the distribution of θ, and the emission angle distribution of the stimulable phosphor panel 94 of Comparative Example 2 in which the light converging layer 54 is adhered to the fluorescent layer 56 with the adhesive layer 60 is not much different from the cos θ distribution.
That is, the intensity distribution B1 of the stimulated emission light K generated from the stimulable phosphor panel 93 of Comparative Example 1 and the stimulable phosphor panel 94 of Comparative Example 2 (see the emission angle distribution of FIG. 17 (a)) is
It can be seen that the distribution is close to the cos θ distribution.

However, in the stimulable phosphor panels 91 and 92 of Examples 1 and 2, the intensity ratio deviates from the cos θ distribution as the angle increases, and this intensity ratio decreases compared to the cos θ distribution. Was confirmed. That is, the intensity distribution B2 of the stimulated emission light generated from the stimulable phosphor panels 91 and 92 of Example 1 and Example 2 (see the emission angle distribution of FIG. 17 (b)) is deviated from the cos θ distribution and is 0 ° direction. It can be seen that the intensity of the light going toward is high, that is, the directivity of the light in the 0 ° direction is high.

Next, as shown in FIG. 18, the linear light source 7 for irradiating the stimulable phosphor panel 66 with the linear excitation light Le extending in the direction perpendicular to the paper surface (hereinafter referred to as the main scanning X direction).
0, and a CCD 71 extending in the main scanning X direction for measuring the amount of stimulated emission light generated from the stimulable phosphor panel 66.
And a self-stimulated luminescent light detection including a selfoclens array 72 for forming an image of the stimulable luminescent light K generated from the stimulable phosphor panel 66 by the irradiation of the linear excitation light Le on the light receiving surface of the CCD 71. Using the device 73, the amount of stimulated emission light generated from the stimulable phosphor panels 91 to 94 irradiated with the linear excitation light extending in the main scanning X direction was measured.

The SELFOC lens array 72 is composed of a large number of SELFOC lenses arranged in parallel in the main scanning X direction, and when detecting stimulated emission light generated from the stimulable phosphor panel, The Selfoc lens array 7
A plane perpendicular to the main scanning X direction of 2 (plane parallel to the paper surface)
The angle of view α at is ± 20 °.

Further, each of the stimulable phosphor panels 91 to 9 described above
For No. 4, the one to which a certain X-ray dose was previously irradiated was used.

Table 2 shows the relative amount of light emitted from each of the stimulable phosphor panels 91 to 94 when the amount of stimulated emission light measured using the stimulable phosphor panel 93 of Comparative Example 1 is 100.

As shown in Table 2, the amount of stimulated emission light detected in the stimulable phosphor panels of Examples 1 and 2 was detected in the stimulable phosphor panels of Comparative Example 1 and Comparative Example 2. It is understood that the amount of the stimulated emission light is larger than that of the generated stimulated emission light, and the directivity of the stimulated emission light generated from the stimulable phosphor panel is improved.

[0063]

[Table 2] 3. Supplementary explanation A supplementary explanation will be given below of the case where the light converging layer is adhered via the glue layer. FIG. 19 is a sectional view showing a stimulable phosphor panel in which a light converging layer is laminated via an air layer and a stimulable phosphor panel in which a light converging layer is laminated via an adhesive layer.

When the light converging layer 54 is made of resin, the refractive index is usually 1.5 to 1.65. Further, the refractive index can be increased to about 2 by adding ultrafine particles of titanium oxide or the like to increase the refractive index.

As shown in FIG. 19A, in the case of the stimulable phosphor panel 91 in which the air layer 55 is formed between the phosphor layer 56 and the light-collecting east layer 54, the air layer 55 Due to the difference in refractive index between the light converging layer 54 and the light converging layer 54,
The light incident on is focused. Further, when the light is emitted from the light converging layer 54, the spread of the light is suppressed by the converging effect of the light converging layer 54. In the case where a smooth film is laminated instead of the light converging layer, when light is emitted from the film to the outside air, as indicated by a chain double-dashed line G1 due to a difference in refractive index between the film and the outside air. Further, the light flux will be expanded.

On the other hand, as shown in FIG. 19 (b), the glue layer 60
In the case of the stimulable phosphor panel 94 in which the light converging layer 54 and the phosphor layer 56 are bonded to each other through the resin, the adhesive layer 60 made of resin usually has a refractive index of about 1.5 to 1.6 and a difference in refractive index from the light converging layer 54. Is small, the converging property of the light incident from the glue layer 60 to the light converging layer 54 is lower than the converging property of the light incident from the air layer 55 to the light converging layer 54, and finally emitted. The convergence of the emitted light is also reduced. In the case where a smooth film is laminated instead of the light converging layer 54, when light is emitted from the film to the outside air, as indicated by a chain double-dashed line G2 due to a difference in refractive index between the film and the outside air. Then the light flux will spread further.

Therefore, when the glue layer is used, it is preferable that the refractive index of the light converging layer is sufficiently higher than that of the glue layer.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic configuration of a stimulable phosphor panel according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a stimulable phosphor panel.

FIG. 3 is a diagram showing a spread of a luminous flux of stimulated emission light emitted through a gas layer.

FIG. 4 is a diagram showing a spread of a luminous flux of stimulated emission light emitted without passing through a gas layer.

FIG. 5 is a conceptual diagram comparing the area of a gas layer with the area of a region occupied by a physical contact point.

FIG. 6 is a conceptual diagram showing a plurality of microlenses arranged corresponding to one pixel of a radiation image.

FIG. 7 is a diagram showing the directivity of stimulated emission light emitted through a light converging layer.

FIG. 8 is a side sectional view of a light converging layer having a coating layer.

FIG. 9 is a perspective view showing various shapes of microlenses.

FIG. 10 is a cross-sectional view showing a side surface of a stimulable phosphor panel in which a stimulable phosphor layer and a light converging layer are bonded with an adhesive.

FIG. 11 is a sectional view showing a schematic configuration of a stimulable phosphor panel of Example 1.

FIG. 12 is a sectional view showing a schematic configuration of a stimulable phosphor panel of Example 2.

FIG. 13 is a sectional view showing a schematic configuration of a stimulable phosphor panel of Comparative Example 1.

FIG. 14 is a sectional view showing a schematic configuration of a stimulable phosphor panel of Comparative Example 2.

FIG. 15 is a conceptual diagram showing a schematic configuration of an evaluation device.

FIG. 16 is a diagram showing measurement results of emission angle distribution.

FIG. 17 is a diagram showing an emission angle distribution of stimulated emission light generated from a stimulable phosphor panel.

FIG. 18 is a conceptual diagram showing a schematic configuration of a stimulated emission light detection device.

FIG. 19 is a cross-sectional view showing a stimulable phosphor panel in which a light converging layer is laminated via an air layer and a stimulable phosphor panel in which a light converging layer is laminated via an adhesive layer.

FIG. 20 is a side view showing a state of excitation light that is repeatedly reflected and propagated in a thick gas layer.

FIG. 21 is a side view showing a state of excitation light that is repeatedly reflected and propagated in a thin gas layer.

FIG. 22 is a diagram showing how the excitation light Le or the stimulated emission light K spreads over a wide range on the stimulable phosphor layer when the light converging layer becomes thick.

[Explanation of symbols]

10 Storage phosphor layer 20 Light converging layer 21 Micro Prism 30 gas layer P Physical contact point

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G083 AA03 CC08 CC10 DD01 DD11                       DD12 DD17 EE02                 2H013 AB01 AC04

Claims (5)

[Claims] 1. A stimulable phosphor layer and a stimulable phosphor layer laminated on the stimulable phosphor layer, which is irradiated with excitation light to converge and transmit a luminous flux of stimulated emission light generated from the stimulable phosphor layer. A stimulable phosphor panel comprising a light converging layer, wherein the stimulable phosphor layer and the light converging layer are brought into contact with each other through evenly distributed physical contact points, and the accumulation Storage phosphor panel, wherein a gas layer is formed between the phosphor layer and the light converging layer. 2. The value of the ratio R of the area occupied by the contact points to the area of the laminated region in which the stimulable phosphor layer and the light converging layer are laminated is 0 <R ≦ 30%. The stimulable phosphor panel according to claim 1, which is characterized in that. 3. The stimulable phosphor panel according to claim 1, wherein the light converging layer comprises a plurality of microlenses arranged in a plane. 4. The light converging layer has a thickness of 1 μm or more and 100.
μm or less and the microlenses have a pitch of 5
The stimulable phosphor panel according to claim 3, wherein the stimulable phosphor panels are arranged in parallel with each other with a thickness of 0 μm or less. 5. The stimulable phosphor panel according to claim 1, wherein the light converging layer is a resin film having surface irregularities.