JP2016054880A - Light source device for collimator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device for a collimator, which can improve an illuminance ratio between the inside and the outside of an irradiation field of visible light.SOLUTION: A light source device 10 for a collimator has an LED 11 with a light emitting part 12 for applying a visible light and a visible light guide member 20. The visible light guide member 20 is comprised of a body 21, a spacer 22 and a base 23. A through-hole 24 having a truncated cone shape is bored in the body 21. In the through-hole 24 having the truncated cone shape, an opening part 25 of the LED11 side becomes a top surface and an opening part 26 of the opposite side with the LED11 become a bottom surface. Also, a cone 27 in the through-hole 24 having the truncated cone shape is configured in the shape of a mirror finished surface for reflecting the visible light applied from the LED11 with high reflectance. An area of the opening part 25 of the LED11 side in the through-hole 24 is smaller than the area of the light-emitting surface of light emitting part 12 of the LED11.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a collimator light source device used to display an X-ray irradiation field formed by a collimator with visible light in an X-ray imaging apparatus.

  In such an X-ray imaging apparatus, an X-ray irradiation field that is an irradiation range for the subject of X-rays irradiated from the X-ray tube is regulated between the X-ray tube and the X-ray detector. A collimator, which is an X-ray aperture mechanism, is provided with a plurality of collimator leaves arranged to be openable and closable in an X-ray irradiation area from the X-ray tube. When adjusting the X-ray irradiation field irradiated from the X-ray tube toward the subject using this collimator, a visible light source called a collimator lamp disposed on the opposite side of the patient from the collimator is used. A visible light irradiation field is formed by lighting, and an X-ray irradiation field adjusted by a collimator mechanism is confirmed by viewing the visible light irradiation field (see Patent Document 1 and Patent Document 2).

  Conventionally, a halogen lamp has been used as a visible light source for such a collimator. This halogen lamp has a problem of high power consumption. Another problem is that halogen lamps have a relatively short life and need to be replaced regularly.

  For this reason, a collimator light source device using an LED that emits visible light as a light source has been proposed (see Patent Document 3). In the light source device for a collimator described in Patent Document 3, in order to improve the illuminance ratio (edge contrast) between the irradiation field by visible light and the outer peripheral area of the irradiation field, the compound parabolic condensing is performed. It has a configuration in which LEDs are housed inside a container (CPC) shaped cone.

JP 2001-70292 A JP 2013-215495 A JP 2004-209259 A

  In the collimator light source device described in Patent Document 3 described above, since all of the visible light emitted from the LED is collected on the reflecting surface, the illuminance in the visible light irradiation field is improved, but it faces in all directions. There is a problem in that visible light is condensed, and an illuminance ratio exceeding a certain level cannot be obtained. In the collimator light source device described in Patent Document 3, as described in Patent Document 3, the illuminance ratio in the region 3 mm inside and 3 mm outside from the edge of the visible light irradiation field is 1.458 or 1.923. It is only a degree.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a collimator light source device capable of further improving the illuminance ratio between the inside and outside of the visible light irradiation field.

  The invention described in claim 1 is a light source device for a collimator used for displaying an X-ray irradiation field formed by a collimator with visible light in an X-ray imaging apparatus, and an LED for irradiating visible light; A visible light guide member that condenses the visible light emitted from the LED after limiting an irradiation region, and the visible light guide member includes a first opening formed on the LED side; A second opening that is concentric with the first opening and has a larger area than the first opening formed on the opposite side of the LED, the first opening, and the second opening And a side surface of the through hole is configured to have a mirror-like shape that reflects visible light, and an area of the first opening in the through hole is an area of the LED. It is smaller than the area of the light emitting surface.

  The invention according to claim 2 is the invention according to claim 1, wherein the through hole has the first opening as a top surface, the second opening as a bottom surface, and the side surface as a conical surface. It has a frustum shape.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the light emitting surface of the LED and the surface of the region where the LED side opening of the visible light guide member is formed are: Separate by a predetermined distance.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the visible light guide member is configured such that the visible light irradiated from the LED is external from a region other than the through hole. It has a light tight structure that prevents it from being emitted.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the visible light guide member is made of metal, and the conical surface of the through hole is mirror-finished.

  According to the first and second aspects of the present invention, the visible light guide member that condenses the visible light irradiated from the LED after limiting the irradiation area, and the inner side and the outer side of the visible light irradiation field. It is possible to make the illuminance ratio in the region extremely high. This makes it possible to more accurately recognize the irradiation field of visible light, that is, the X-ray irradiation field.

  According to the second aspect of the present invention, the visible light guide member is penetrated by providing a predetermined distance between the light emitting surface of the LED and the surface of the visible light guide member where the LED side opening is formed. Even when the area of the LED-side opening in the hole is increased, the illuminance ratio in the region inside and outside the visible light irradiation field can be made extremely high.

  According to the third aspect of the present invention, the visible light guide member has a light tight structure that prevents the visible light from being emitted outside from the region other than the through hole, so that the stray light emitted from the LED is visible. It is possible to prevent the phenomenon of reaching the vicinity of the light irradiation field and lowering the illuminance ratio.

  According to invention of Claim 4, even if it is a case where big heat_generation | fever arises from LED using a high output LED by comprising a visible light guide member from a metal, a visible light guide member deteriorates. This can be prevented and the heat can be quickly released to the outside.

1 is a schematic diagram of an X-ray imaging apparatus to which a collimator light source device 10 according to the present invention is applied. 3 is a schematic diagram of a collimator 43. FIG. It is a perspective view of the light source device 10 for collimators. 3 is an enlarged cross-sectional view of the visible light guide member 20 of the collimator light source device 10 in the vicinity of a through hole 24. FIG. It is a schematic diagram which shows the state which the visible light irradiated from the light emission part 12 of LED11 is interrupted by the collimator leaf 53, and forms the irradiation field of visible light. It is a graph which compares the illuminance ratio when the light source device for collimators 10 has a light tight structure and when it does not have a light tight structure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of an X-ray imaging apparatus to which a collimator light source device 10 according to the present invention is applied.

  This X-ray imaging apparatus includes an X-ray imaging table 3 and an X-ray irradiation unit 4 installed in an X-ray imaging room. The X-ray imaging table 3 includes a top panel 31 on which a subject is placed, an operation panel 32 having a display unit 35 composed of a touch panel type liquid crystal display, and an X-ray detector such as a flat panel detector. A bucky part 33 housed therein and a lifting part 34 for raising and lowering the top plate 31 and the bucky part 33 are provided. The bucky part 33 is horizontally movable in the G direction shown in FIG. Further, the bucky part 33 can be moved up and down in the F direction shown in FIG.

  The X-ray irradiation unit 4 includes a support unit 61 that can move in the A direction and the B direction orthogonal to the ceiling of the X-ray imaging room, a hanging part 62 that extends downward from the supporting part 61, and the hanging part 62. The moving unit 63 that moves up and down in the C direction and pivots in the D direction and is pivotally supported by the lower end of the moving unit 63, and the operation unit 41, the X-ray tube 42, and the collimator 43 are integrated in the E direction. And a support shaft 64 to be rotated. For this reason, the X-ray tube 42 is movable in the A, B, C, D, and E directions shown in FIG.

  FIG. 2 is a schematic diagram of the collimator 43.

  The collimator 43 includes four collimator leaves 53 for limiting the X-ray irradiation field irradiated from the X-ray tube 42. In this figure, only two collimator leaves 53 are shown, but in reality, a rectangular X-ray irradiation field is formed by the four collimator leaves 53. In this figure, reference numeral 100 denotes an X-ray irradiation field and a visible light irradiation field described later. Further, the collimator 43 includes the collimator light source device 10 according to the present invention that emits visible light for making the X-ray irradiation field visible. Visible light emitted from the collimator light source device 10 is reflected in the direction of the collimator leaf 53 by the mirror 52 that can transmit X-rays, and a rectangular visible light irradiation field is formed by the four collimator leaves 53. . The size of the visible light irradiation field is the same as the size of the X-ray irradiation field. The operator can confirm the X-ray irradiation field by confirming the irradiation field of the visible light.

  Next, the configuration of the collimator light source device 10 according to the present invention will be described. FIG. 3 is a perspective view of the collimator light source device 10. FIG. 4 is an enlarged sectional view of the vicinity of the through hole 24 in the visible light guide member 20 of the collimator light source device 10. In addition, in FIG. 3, in order to illustrate the internal structure of the visible light guide member 20, the state which cut | disconnected the visible light guide member 20 in half is illustrated.

  The collimator light source device 10 includes an LED (Light Emitting Diode) 11 including a light emitting unit 12 that emits visible light. The light emitting section 12 in the LED 11 may be provided with a single light irradiation area, may be provided with a plurality of light irradiation areas, or may be provided with a large number of light emitting elements arranged in a line.

  The collimator light source device 10 includes a visible light guide member 20 that condenses the visible light emitted from the LED 11 after limiting the irradiation area. The visible light guide member 20 includes a main body 21, a spacer 22, and a base 23 made of metal. The main body 21, the spacer 22, and the base 23 are formed by utilizing a fastening hole 29 formed in the main body 21, a fastening hole (not shown) formed in the spacer 22, and a fastening hole 28 formed in the base 23. These are fixed to each other by screws or the like not shown.

  A through hole 24 having a truncated cone shape is formed in the main body 21 of the visible light guide member 20. In the through-hole 24 having a truncated cone shape, an opening (first opening) 25 on the LED 11 side is a top surface, and an opening (second opening) 26 opposite to the LED 11 is a bottom surface. It has become. Further, the conical surface (side surface) 27 in the through-hole 24 having the truncated cone shape is configured to have a mirror surface shape that reflects visible light emitted from the LED 11 with high reflectance. And the area of the opening part 25 by the side of LED11 in the through-hole 24 is smaller than the area of the light emission surface of the light emission part 12 of LED11.

  As shown in FIG. 3, the light emitting unit 12 of the LED 11 has a rectangular shape in plan view. And what is the length of one side of the light emitting unit 12? As shown in FIG. 4, it is D1. On the other hand, the diameter D2 of the opening 25 on the LED 11 side formed in the main body 21 of the visible light guide member 20 is smaller than the length D1 of one side of the light emitting unit 12 of the LED 11. Therefore, the area of the opening 25 on the LED 11 side in the through hole 24 is smaller than the area of the light emitting surface of the light emitting part 12 of the LED 11.

  Moreover, as shown in FIG. 4, the angle which the cone surface 27 in the through-hole 24 which has a truncated cone shape makes with the perpendicular direction is (theta). And the light emission surface which is the upper surface of the light emission part 12 in LED11, and the surface (lower surface) of the area | region in which the opening part 25 by the side of LED11 in the main body 21 of the visible light guide member 20 is separated by predetermined distance d. ing.

  Further, a plurality of spacers 22 having different thicknesses are prepared for the visible light guide member 20. For this reason, by appropriately selecting the thickness and the number of the spacers 22, the light emitting surface that is the upper surface of the light emitting portion 12 in the LED 11 and the opening portion 25 on the LED 11 side in the main body 21 of the visible light guide member 20 are formed. It becomes possible to change the distance d to the surface. When this distance d is increased, the illuminance in the areas inside and outside the visible light irradiation field even when the area of the opening 25 on the LED 11 side in the through hole 24 of the visible light guide member 20 is increased. The ratio can be made high. However, when the area of the opening 25 on the LED 11 side in the through hole 24 of the visible light guide member 20 can be reduced, the distance d may be zero.

  A concave portion is formed in the visible light guide member 20 in the region facing the LED 11 by the leg portion 39 of the main body 21 and the spacer 22, and the LED 11 is accommodated in the concave portion. For this reason, the LED 11 is surrounded by the main body 21, the spacer 22, and the base 23 in the visible light guide member 20. Thereby, the visible light guide member 20 has a light tight structure that prevents visible light emitted from the light emitting unit 12 in the LED 11 from being emitted to the outside from a region other than the through hole 24.

  In addition, the main body 21 in the visible light guide member 20 is manufactured by pressing aluminum (Al). And the conical surface 27 in the through-hole 24 of the main body 21 is subjected to ironing processing (ironing) at the time of pressing, so that the surface roughness is sufficiently fine and smooth, and the reflectance of visible light is about 80%. Mirror surface.

  In the collimator light source device 10 having the above configuration, since the area of the opening 25 on the LED 11 side in the through hole 24 is smaller than the area of the light emitting surface of the light emitting part 12 of the LED 11, the light is emitted from the light emitting part 12 of the LED 11. Of the emitted light 12, only visible light from the central region of the light emitting unit 12 where the emission intensity is highest enters the through hole 24 from the opening 25. In this way, by limiting the irradiation area of the visible light taken into the visible light guide member 20 out of the visible light irradiated from the light emitting unit 12 of the LED 11, the inside and outside of the visible light irradiation field are limited. It is possible to increase the illuminance ratio in the region.

  FIG. 5 is a schematic diagram illustrating a state in which visible light irradiated from the light emitting unit 12 of the LED 11 is blocked by the collimator leaf 53 to form a visible light irradiation field.

  As shown by the solid line in this figure, when the region of visible light irradiated from the light emitting unit 12 and entering the through hole 24 is reduced, the range of visible light emitted from both ends of the region and blocked by the collimator leaf 53 Becomes L1. On the other hand, as shown by a broken line in this figure, when the region of visible light irradiated from the light emitting unit 12 and entering the through hole 24 is enlarged, visible light emitted from both ends of the region and blocked by the collimator leaf 53 The range of L2 is larger than L1. The ranges L1 and L2 are regions where the shadow of the collimator leaf 53 blurs at the edge of the visible light irradiation field, and the illuminance ratio decreases as the width of this region increases. As shown in FIG. 5, by reducing the area of visible light irradiated from the light emitting unit 12 and entering the through-hole 24, the area where the shadow is blurred is reduced, and the areas inside and outside the visible light irradiation field are reduced. It becomes possible to maintain a high illuminance ratio.

  On the other hand, the visible light irradiated from the light emitting part 12 in the LED 11 and entering the through hole 24 through the opening 25 is condensed by being reflected by the conical surface 27 in the through hole 24 having a truncated cone shape, and is visible. Form a light field. As described above, even when a configuration in which only a part of the visible light irradiated from the light emitting unit 12 in the LED 11 enters the through hole 24 is adopted, the light emitting unit in the LED 11 using the reflection on the conical surface 27. The visible light irradiated from 12 can be efficiently guided to the visible light irradiation field, and the illuminance of the visible light irradiation field can be increased. In this case, the illuminance of the visible light irradiation field can be maximized by setting the angle θ between the conical surface 27 of the through hole 24 having a truncated cone shape and the vertical direction to about 16 degrees to 19 degrees. Become.

  In the collimator light source device 10 having such a configuration, according to experiments by the inventors of the present invention, a light emitting surface on the upper surface of the light emitting portion 12 in the LED 11 and an opening 25 on the LED side in the visible light guide member 20 are formed. When the distance d to the surface of the region is 0.4 mm to 0.7 mm and the diameter of the opening 25 is 1.65 mm to 1.85 mm, the illuminance of visible light around the visible light irradiation field is It was confirmed that the illuminance ratio between the area 3 mm inside and the area 3 mm outside the area that is ¼ of the maximum illuminance of the visible light irradiation field can be 4.0 or more.

  In the above-described collimator light source device 10, the LED 11 is surrounded by the main body 21, the spacer 22, and the base 23 in the visible light guide member 20, and the visible light guide member 20 is a light emitting unit in the LED 11. 12 has a light-tight structure that prevents visible light emitted from 12 from being emitted to the outside from a region other than the through hole 24. For this reason, in this collimator light source device 10, it is possible to prevent a phenomenon in which stray light irradiated from the light emitting unit 12 of the LED 11 reaches the vicinity of the irradiation field of visible light and lowers the illuminance ratio.

  FIG. 6 is a graph comparing the illuminance ratio when the collimator light source device 10 has a light tight structure and when it does not have a light tight structure. The horizontal axis in FIG. 6 indicates the distance from the center of the visible light irradiation field, and the vertical axis indicates a region 3 mm outside the region where the illuminance of visible light is ¼ of the maximum illuminance of the visible light irradiation field. The illuminance normalized by the maximum illuminance is shown. Moreover, in this figure, a solid line shows the case where the light source device 10 for collimators mentioned above is applied, and a broken line shows the case where the area | region equivalent to the leg part 39 in the main body 21 of the visible light guide member 20 is open | released.

  As shown in this figure, when the visible light guide member 20 in the collimator light source device 10 has a light-tight structure, the illuminance of visible light is the maximum of the visible light irradiation field compared to the case where the light-tight structure is not used. It is possible to reduce the illuminance in the region 3 mm outside the region that is ¼ of the illuminance, and to increase the illuminance ratio in the region outside and inside the visible light irradiation field.

  In the above-described embodiment, the through-hole 24 having a truncated cone shape is employed, but other truncated cone shapes such as a polygonal truncated cone may be employed. For example, a square frustum corresponding to a rectangular irradiation field formed by the collimator leaf 53 may be adopted as the shape of the through hole 24. Moreover, as long as the visible light irradiated from the LED light source can be efficiently collected, it is possible to employ a through hole having a shape other than the frustum shape. For example, it has a shape in which the opening 25 and the opening 26 are connected not by a straight line but by a surface composed of another curve such as a parabola, or by a surface composed of a line connecting a straight line and a curve. A through hole may be employed.

  Moreover, in embodiment mentioned above, what was manufactured by pressing aluminum as the main body 21 of the visible light guide member 20 is employ | adopted. Thereby, the manufacturing cost of the main body 21 of the visible light guide member 20 can be reduced. In addition, even when heat is generated from the LED 11 by using a high output LED 11, the LED 11 does not deteriorate and has high thermal conductivity, so that the heat generated from the LED 11 is efficiently dissipated. It becomes possible to do. However, instead of aluminum, other metals or alloys having high thermal conductivity may be used, or a reflective film may be deposited on the surface of the material that has been shaped and sintered with ceramics or the like. Further, when the heat generated from the LED 11 is small, a resin film having a reflective film deposited on the surface thereof may be used.

3 X-ray imaging table 4 X-ray irradiation unit 10 Collimator light source device 11 LED
DESCRIPTION OF SYMBOLS 12 Light emission part 20 Visible light guide member 21 Main body 22 Spacer 23 Base 24 Through-hole 25 Opening part 26 Opening part 27 Conical surface 31 Top plate 33 Bucky part 39 Leg part 42 X-ray tube 43 Collimator 52 Mirror 53 Collimator leaf

Claims (5)

In an X-ray imaging apparatus, a collimator light source device used to display an X-ray irradiation field formed by a collimator with visible light,
LEDs that emit visible light;
A visible light guide member that condenses the visible light emitted from the LED after limiting the irradiation area;
The visible light guiding member is concentric with the first opening formed on the LED side and the first opening having a larger area than the first opening formed on the opposite side of the LED. A through-hole having a cylindrical second opening and a side surface connecting the first opening and the second opening is formed, and the side surface of the through-hole reflects the visible light. The collimator light source device is characterized in that the area of the first opening in the through hole is smaller than the area of the light emitting surface of the LED. The light source device for a collimator according to claim 1,
The light source device for a collimator having a frustum shape in which the first opening is a top surface, the second opening is a bottom surface, and the side surface is a frustum. In the collimator light source device according to claim 2,
A light source device for a collimator, wherein a light emitting surface of the LED and a surface of a region where the LED side opening of the visible light guide member is formed are separated by a predetermined distance. In the light source device for collimators according to any one of claims 1 to 3,
The visible light guide member is a light source device for a collimator having a light tight structure that prevents visible light emitted from the LED from being emitted outside from a region other than the through hole. The light source device for a collimator according to any one of claims 1 to 4,
The light source device for a collimator, wherein the visible light guide member is made of metal, and the conical surface of the through hole is mirror-finished.

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