Patent Number: 
Section: claims

1. A collimator comprising:a pair of first plate members having X-ray absorbability, movable in a direction parallel to surfaces thereof, and having respective end faces opposed to each other, with an X-ray passing aperture being defined by a spacing between the opposed end faces of the first plate members; anda pair of second plate members each of which has X-ray absorbability, is capable of being folded in a zigzag fashion through hinges, and is connected at one end thereof to an end of each of the pair of first plate members on the side opposite to the opposed end faces of the first plate members and connected at the other end thereof to a fixing portion in order to intercept other X-rays than the X-ray passing through the aperture. 2. A collimator according to claim 1, wherein the pair of first plate members is movable independently of each other. 3. A collimator according to claim 1, further comprising:a pair of third plate members having X-ray absorbability, being movable in a direction parallel to surfaces thereof and perpendicular to the moving direction of the first plate members, and having respective end faces opposed to each other, with an X-ray passing aperture being defined by a spacing between the opposed end faces of the third plate members; and a pair of fourth plate members each of which has X-ray absorbability, is capable of being folded in a zigzag fashion through hinges, and is connected at one end thereof to and end of each of the third pair of plate members on the side opposite to the opposed end faces of the third plate members and connected at the other end thereof to a fixing portion in order to intercept other X-rays than the X-ray passing through the aperture. 4. A collimator according to claim 3, wherein the pair of third plate members is movable independently of each other. 5. An X-ray irradiator comprising:an X-ray tube; anda collimator for collimating X-ray emitted from the X-ray tube,the collimator comprising:a pair of first plate members having X-ray absorbability, movable in a direction parallel to surfaces thereof, and having respective end faces opposed to each other, with an X-ray passing aperture being defined by a spacing between the opposed end faces of the first plate members; anda pair of second plate members each of which has X-ray absorbability, is capable of being folded in a zigzag fashion through hinges, and is connected at one end thereof to an end of each of the pair of first plate members on the side opposite to the opposed end faces of the first plate members and connected at the other end thereof to a fixing portion in order to intercept other X-rays than the X-ray passing through the aperture. 6. An X-ray irradiator according to claim 5, wherein the pair of first plate members is movable independently of each other. 7. An X-ray irradiator according to claim 5, wherein the collimator further comprises:a pair of third plate members having X-ray absorbability, movable in a direction parallel to surfaces thereof and perpendicular to the moving direction of the first plate members, and having respective end faces opposed to each other, with an X-ray passing aperture being defined by a spacing between the opposed end faces of the third plate members; anda pair of fourth plate members each of which has X-ray absorbability, is capable of being folded in a zigzag fashion through hinges, and is connected at one end thereof to and end of each of the third pair of plate members on the side opposite to the opposed end faces of the third plate members and connected at the other end thereof to a fixing portion in order to intercept other X-rays than the X-ray passing through the aperture. 8. An X-ray irradiator according to claim 7, wherein the pair of third plate members is movable independently of each other. 9. An X-ray apparatus comprising:an X-ray tube;a collimator for collimating X-ray emitted from theX-ray tube and applying the collimated X-ray to an object to be radiographed; anda detector device for detecting the X-ray which has passed through the object to be radiographed,the collimator comprising:a pair of first plate members having X-ray absorbability, movable in a direction parallel to surfaces thereof, and having respective end faces opposed to each other, with an X-ray passing aperture being defined by a spacing between the opposed end faces of the first plate members; anda pair of second plate members each of which has X-ray absorbability, is capable of being folded in a zigzag fashion through hinges, and is connected at one end thereof to an end of each of the pair of first plate members on the side opposite to the opposed end faces of the first plate members and connected at the other end thereof to a fixing portion in order to intercept other X-rays than the X-ray passing through the aperture. 10. An X-ray apparatus according to claim 9, wherein the pair of first plate members is movable independently of each other. 11. An X-ray apparatus according to claim 9, wherein the collimator further comprises:a pair of third plate members having X-ray absorbability, being movable in a direction parallel to surfaces thereof and perpendicular to the moving direction of the first plate members, and having respective end faces opposed to each other, with an X-ray passing aperture being defined by a spacing between the opposed end faces of the third plate members; anda pair of fourth plate members each of which has X-ray absorbability, is capable of being folded in a zigzag fashion through hinges, and is connected at one end thereof to and end of each of the third pair of plate members on the side opposite to the opposed end faces of the third plate members and connected at the other end thereof to a fixing portion in order to intercept other X-rays than the X-ray passing through the aperture. 12. An X-ray apparatus according to claim 11, wherein the pair of third plate members is movable independently of each other.