JP2013217984A - Diaphragm device, optical system and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique advantageous in reducing operating noise of a diaphragm device.SOLUTION: In a diaphragm device that restricts the opening of an optical system by a plurality of light-blocking blades overlapping each other, the light-blocking blade 2-A includes a linear contact part 15-A provided with a face that contacts a member adjacent to the light-blocking blade 2-A.

Description

  The present invention relates to a diaphragm device, an optical system, and an exposure apparatus.

  In Patent Document 1, in a variable aperture mechanism that changes the aperture of an optical system by aperture blades, the sliding resistance between the aperture blades is reduced by applying an alloy plating containing at least nickel and phosphorus on the surface of the aperture blades. Is disclosed. In Patent Document 2, in a diaphragm device having a plurality of diaphragm blades, operating noise of the diaphragm blades is reduced by providing a blade separation portion that separates adjacent diaphragm blades when opening and closing the plurality of diaphragm blades. Is disclosed. The blade spacing portion includes a plurality of first protrusions provided on the back surface side (side facing the fixed ring) of the diaphragm blades, and a plurality of blades provided on the fixed ring so as to contact the plurality of first protrusions. It is comprised with a 2nd projection part.

JP 2002-202543 A JP 2010-078956 A

  In the variable diaphragm mechanism described in Patent Document 1, the diaphragm blades rub against each other to generate a corresponding operating noise. The diaphragm device described in Patent Document 2 separates adjacent diaphragm blades when opening and closing the diaphragm blades, but the diaphragm blades contact each other when the movement of the diaphragm blades starts and ends. Since this is a state, a corresponding operation sound can still be generated.

  The present invention has been made on the basis of the above-mentioned problem recognition, and an object thereof is to provide a technique that is advantageous for reducing the operation sound of the diaphragm device.

  One aspect of the present invention relates to a diaphragm device that defines an aperture of an optical system by a plurality of light shielding blades that overlap each other, and each light shielding blade has a contact surface that contacts an adjacent member adjacent to the light shielding blade. The contact part of a shape is included.

  ADVANTAGE OF THE INVENTION According to this invention, the technique advantageous to reduction of the operating sound of an aperture device is provided.

Sectional drawing explaining the structure of the aperture_diaphragm | restriction apparatus of embodiment of this invention. The figure explaining operation | movement of the aperture blade in the aperture_diaphragm | restriction apparatus of embodiment of this invention. The figure explaining the structure of the diaphragm | throttle device of embodiment of this invention. The figure explaining the linear contact part provided in the aperture blade in the aperture_diaphragm | restriction apparatus of embodiment of this invention. The figure which illustrates the linear contact part provided in the diaphragm blade in the diaphragm | throttle device of embodiment of this invention. The figure which illustrates the diaphragm | throttle device of the diaphragm | throttle device of embodiment of this invention. The figure which illustrates the structural example of the linear contact part of a light-shielding feather.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[First embodiment]
FIG. 3 is a diagram showing a configuration of the diaphragm device 100 according to one embodiment of the present invention. FIG. 1A is a cross-sectional view taken along line AA ′ in FIG. FIG.1 (b) is the figure which looked at the light-shielding feather 2 from the left side in Fig.1 (a). FIG. 1C is an enlarged view of a part of FIG. The diaphragm device 100 is configured to define an aperture OP of the optical system by a plurality of light shielding blades 2 that overlap each other. Each shading feather 2 includes linear contact portions 15 and 16 having contact surfaces that come into contact with other shading feathers 2. Here, each light shielding feather 2 may have a contact portion on one or both of the first surface S1 and the second surface S2 facing the other two light shielding feathers 2, respectively. In the example shown in FIG. 1, each shading feather 2 has a contact portion 15 on the first surface S1, and a contact portion 16 on the second surface S2. The linear contact portions 15 and 16 are configured to extend along the first surface S1 and the second surface S2 of each light shielding feather 2.

  The contact parts 15 and 16 have contact surfaces C <b> 1 and C <b> 2 that come into contact with two other light shielding feathers 2, respectively. The contact surface C1 of the contact portion 15 is a surface protruding from the first surface S1, and the contact surface C2 of the contact portion 16 is a surface protruding from the second surface S2. Of the contact surface C1, at least a portion that can come into contact with the other light-shielding feathers 2 in the adjustment of the opening OP by driving the plurality of light-shielding feathers 2 is a single flat surface as shown in FIG. Can belong to.

  The shading feather 2 has a guide pin 5 and a pivot pin 6. The pivot pin 6 is inserted into a pivot receiver (pivot hole) 7 provided in the base 1, and the light shielding wing 2 can rotate around the pivot receiver 7. The guide plate 3 is positioned so as to be rotatable with respect to the ring portion 8 provided on the base 1. A guide groove 4 is provided in the guide plate 3, and a guide pin 5 is inserted into the guide groove 4. Here, the base 1 can be understood as a stationary ring or a support member that supports the light shielding wing 2. The linear contact portion 16 can be in contact with the light shielding feather receiving surface 9 of the base 1 as well as the other light shielding feather 2. Further, the linear contact portion 16 of the light shielding wing 2 is a portion in contact with an adjacent member adjacent to the light shielding wing 2 (in this example, the other light shielding wing 2 and the light shielding wing receiving surface 9 of the base 1). Can be understood as

  As illustrated in FIG. 3, the plurality of light shielding feathers 2 are arranged in a ring shape so as to overlap the first surface S <b> 1 of each light shielding feather 2 so that the second surface S <b> 2 of the other light shielding feather 2 faces. Yes. A circular opening 10 centered on the optical axis center 11 is formed at the center of the ring. Guide grooves 4 provided in the guide plate 3 guide the guide pins 5 of the plurality of light shielding blades 2. When the guide plate 3 is rotationally driven about the optical axis center 11 by the actuator (not shown), the guide groove 4 moves, and the light shielding blade 2 also moves along the guide groove 4.

  The movement of the shading feather 2 will be described in more detail with reference to FIG. 2A, 2B, and 2C, two light shielding feathers 2 (2-A, 2-B) among the plurality of light shielding feathers 2 are shown in order to simplify the description. 2A, 2B, and 2C, two of the plurality of pivot pins 6 are distinguished as two pivot pins (6-A and 6-B), and two of the plurality of guide pins 5 are guides. Two guide grooves (4-A, 4-B) among the plurality of guide grooves 4 are shown.

  The light shielding wing 2-A is rotatable about the pivot pin 6-A, and the light shielding wing 2-B is rotatable about the pivot pin 6-B. As shown in FIG. 2B, the guide plate 3 is disposed on the light shielding feathers 2-A and 2-B, and the guide pin 5-A is inserted into the guide groove 4-A. B is inserted into the guide groove 4-B. When the guide plate 3 is rotated in the rotation direction 12 with the optical axis center 11 as an axis, the guide pin 5-B is pushed out in the outer circumferential direction, and the light shielding blade 2-B rotates in the rotation direction 13 with the pivot pin 6-B as an axis. To turn. At this time, the ridge line drawn by the edge on the optical axis center side of the light shielding feathers 2-A and 2-B is the circular shape shown in the opening 10-A in the state of FIG. In the state 2 (c), the circumferential shape shown in the opening 10-B is formed, and the opening diameter is large. Each of the light shielding feathers 2-A and 2-B is configured using a light shielding plate having a light shielding property with respect to the wavelength of light used in the optical system including the diaphragm device 100 as a base material. The aperture 10 can constitute a pupil in the optical system.

  Since the light shielding feathers 2-A and 2-B have an overlap margin, they move while being slid in the overlap margin portion while being driven. As described above, the linear contact portions 15 and 16 are formed on the first surface S1 and the second surface S2 of the light shielding feather 2. Therefore, in FIG. 2A, the contact portion 15 provided on the first surface S1 of the light shielding feather 2-A and the contact portion 16 provided on the second surface S2 of the light shielding feather 2-B come into contact with each other. Yes.

  FIG. 4 illustrates the configuration of the linear contact portions 15 and 16 as contact portions 15-A and 16-B. On the first surface (front surface) S1 of the light shielding feather 2-A, a plurality of linear contact portions are formed at the same pitch as an array of the plurality of linear contact portions 15-A. In one example, the surface of the contact portion 15-A can be provided at a position that is higher than the first surface (front surface) of the light shielding feather 2-A by a height in the range of 10 μm to 20 μm in the front side of the drawing (ie, the contact portion). The height of 15-A may be in the range of 10 μm to 20 μm). The width of each contact portion 15-A may be 100 μm, and the arrangement pitch of the plurality of contact portions 15-A may be 2 mm. The surface of the contact portion 15-A can be configured by covering a base material constituting the contact portion 15-A with DLC (Diamond-Like Carbon). On the second surface (back surface) S2 of the light shielding blade 2-B, a plurality of linear contact portions are formed at the same pitch as an array of the plurality of linear contact portions 15-B. The plurality of linear contact portions 15-B may have the same configuration as the plurality of linear contact portions 15-A.

  The plurality of linear contact portions 15-A and the plurality of linear contact portions 15-B are provided so as to cross each other (for example, orthogonal). Except for the portion where the plurality of linear contact portions 15-A and the plurality of linear contact portions 15-B are in contact, the first surface (front surface) of the light shielding feather 2-A and the light shielding feather 2-B There is a gap between the second surface (back surface). The light shielding feathers 2-A and 2-B rotate in synchronization with each other. At this time, the angle at which the linear contact portion 15-A and the linear contact portion 15-B intersect is maintained constant, but the linear contact portion 15-A and the linear contact portion 15- The part in contact with B changes. By changing the portion where the linear contact portion 15-A and the linear contact portion 15-B are in contact with each other, the contact portions 15-A and 15-B have an average without wearing a specific portion. Wear out. Further, as described above, the surfaces of the contact portions 15-A and 15-B are made of DLC (the friction coefficient of DLC is typically 0.1 to 0.15), thereby allowing the contact portions. The sliding resistance between 15-A and the contact portion 15-B can be extremely reduced. In particular, when the diaphragm device 100 is used as a pupil stop of a projection optical system of an exposure apparatus that transfers an original plate (reticle) pattern to a substrate, the required number of times of durable sliding drive is, for example, 1 million to 1 billion. In addition, there is a need for oil-free lubrication. Therefore, it is desirable to use a DLC coating having high hardness and excellent solid lubricity in the exposure apparatus.

  In the conventional configuration where the light-shielding blades are in surface contact with each other, the light-shielding blades cause a sticking phenomenon, or the sliding is shown with a friction coefficient larger than the ideal friction coefficient due to minute irregularities on the surface and edges. Resistance can be generated. However, in the diaphragm device according to the first embodiment of the present invention, since the contact area of the sliding portion of the light-shielding blade 2 is reduced, the possibility of causing an adsorption phenomenon is reduced, and stable driving is achieved with low sliding resistance. As a result, durability can be improved and operating noise (sliding noise) can be reduced. When the aperture device is used in an optical system of a camera such as a video camera, the operation sound (sliding sound) may be a recording noise, so that the configuration of the aperture device with a small operation sound is effective. In general, since the diaphragm device is incorporated in the optical system, it does not like the gas derived from the lubricating oil, and since it is desired that there is no refueling operation during the lifetime of the device, the solid lubrication type is useful. . However, it may be necessary to use lubricating oil for the sliding portion of the shading feather 2. In such a case, since the sliding resistance due to the viscosity of the lubricating oil increases, the diaphragm device of the first embodiment having a small contact area on the sliding surface is advantageous.

  Furthermore, the low sliding resistance between the light shielding blades 2 is advantageous in that the material constituting the contact surface is prevented from being peeled off due to wear. Here, when particles generated by wear or particles from the surrounding environment are sandwiched between the contact surfaces, the particles can act as abrasive grains and promote wear. However, according to the first embodiment, the linear contact portions 15, 16 form a gap between the first surface S 1 of the light shielding wing 2 and the second surface S 2 of the light shielding wing 2, and contact with the contact portion 15. When the intersection with the part 16 moves, particles are swept out into the gap. Therefore, an increase in wear due to particles is reduced.

  Further, the low sliding resistance between the light shielding wings 2 allows the actuator that drives the guide plate 3 to rotate the light shielding wings 2 with a small electric power, and the heat generated from the actuator and its driver. Can be reduced. The air layer formed between the light shielding wing 2 and the light shielding wing 2 functions as a heat radiating layer, and can suppress an increase in heat around the diaphragm device 100.

  FIG. 5A shows a configuration of one light shielding blade 2 in FIG. A plurality of linear contact portions 15 are formed in parallel with each other on the first surface (front surface) of the light shielding wing 2, and a plurality of linear contact portions 16 are parallel with each other on the second surface (back surface) of the light shielding wing 2. Is formed. 5A, the light shielding wing 2 is shown in alignment with the position of the light shielding wing 2B in FIG. 4A. The linear contact portion 15 and the linear contact portion 16 intersect at 36 degrees (54 degrees).

  In the example shown in FIGS. 3 and 4, the diaphragm device 100 has ten light shielding blades 2. The light shielding blade 2-A shown in FIG. 4A is a position rotated by 36 degrees counterclockwise about the optical axis center 11 from the position of the light shielding blade 2-B. For this reason, if ten light shielding blades 2 shown in FIG. 5 (a) are continuously arranged according to the arrangement of FIG. 4 (a), linear contact is made at the overlapping portion of all adjacent light shielding blades 2. The parts 15 and 16 are orthogonally combined.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described. Matters not mentioned here can follow the first embodiment. In the first embodiment, the linear contact portions 15 and 16 have a linear shape, but in the second embodiment, the linear contact portions 15 and 16 have a curved shape. A configuration in which at least one of the linear contact portions 15 and 16 has a curved shape is useful, for example, in a diaphragm device in which the light shielding blade 2 rotates. FIG. 5B shows one example of the light shielding feather 2 in the second embodiment, and FIG. 5B shows another example of the light shielding feather 2 in the second embodiment.

  In the example of FIG. 5B, the linear contact portion 15 is formed on the first surface (front surface) of the light shielding wing 2 so as to form a linear shape extending radially from the pivot pin 6 that is the rotation center of the light shielding wing 2. Is formed. Further, on the second surface (back surface) of the light shielding feather 2, when the light shielding feather 2 is disposed at the position of the light shielding feather 2-A in FIG. 4A, the pivot pin 6 in FIG. A plurality of arc-shaped linear contact portions 16 that are concentric with the center are formed. In the example of FIG. 5 (c), the linear contact portion 16 also intersects the light shielding blade receiving surface 9 of the base 1 shown in FIG. In other cases, the sliding resistance can be reduced.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described. FIG. 6 illustrates a diaphragm device 200 according to the third embodiment. The aperture device 200 is configured to adjust the size of the opening 10. The aperture device 200 includes light shielding feathers 2A and 2B that are linearly driven. The light shielding blade 2A is driven in the driving direction 23-A along the guide groove 22A, and the light shielding blade 2B is driven in the driving direction 23-B along the guide groove 22B. Thereby, the area of the opening 10 can be changed continuously or stepwise. Here, a linear contact portion 15 in the 45 degree direction that rises to the right of the paper surface is formed on the surface of the light shielding feather 2A, and a linear contact portion in the 45 degree direction that rises to the left in the paper surface on the back surface of the light shielding feather 2B. 16 is formed. Therefore, the contact parts 15 and 16 are orthogonal to each other and are in point contact with each other. Thereby, quiet driving is possible with a small sliding resistance.

  In addition, the diaphragm | throttle device of this invention may be arrange | positioned not only in the pupil of an optical system but in other positions, such as a focal plane (image surface). The aperture device of the present invention may be configured as a focal plane shutter, for example.

[Fourth embodiment]
The thickness of the light shielding wing 2 may be in the range of 50 μm to 200 μm, for example. The height of the contact portions 15 and 16 can be in the range of 10 μm to 20 μm, for example. Since the diaphragm device is often used as a diaphragm on the pupil plane or the focal plane, when the thickness of the light shielding wing 2 exceeds 1 mm, the optical blur on the pupil plane or the focal plane becomes large. Since the optical performance is deteriorated, such a thin light shielding blade 2 is advantageous. When the height of the contact portion is 10 μm or more, the contact portions 15 and 16 may form a contact portion by forming a low-friction surface treatment layer on the base material and patterning it.

  7A to 7E illustrate configuration examples of the linear contact portions 15 and 16 of the light shielding wing 2. As described above, in order to form the low-friction contact portions 15 and 16, it is advantageous to coat with a DLC film. The thickness of the DLC film can be in the range of 1 μm to 20 μm, for example. In the example of FIGS. 7A and 7B, the base material 19 of the light-shielding blade 2 is configured to be flat on both surfaces, and the linear contact portion 15 made of the DLC film 17 is formed on one surface of the base material 19. The linear contact portion 16 is formed by the DLC film 17 on the other surface of the base material 19. The light shielding feather 2 illustrated in FIG. 7A can be realized, for example, by performing negative type masking on both surfaces of the base material 19 and then covering with a DLC film, and then removing the masking. The light shielding blade 2 illustrated in FIGS. 7A and 7B covers the entire surface of the two surfaces of the base material 19 with a DLC film, and then, except for the portion that should be a linear contact portion. This can be achieved by scraping off by etching or grinding. The light shielding blade 2 illustrated in FIG. 7C and FIG. 7D is formed by forming the DLC film 17 as a low friction film after forming the convex portion 18 on the surface of the base material 19. The light shielding feather 27 illustrated in FIG. 7E is obtained by covering the entire surface of two surfaces of a base material 19 having a corrugated cross section with a DLC film 17.

  As the low friction film, in addition to the DLC film, for example, a film whose surface has a lower coefficient of friction than the surface of the base material 19 such as a hard chromium plating film or a fluorine-containing Kanigen plating film may be used. Etc. are not limited to specific ones.

[Application example]
The diaphragm device can be incorporated into, for example, a camera or its optical system, or an optical system (for example, a projection optical system or an illumination optical system) of an exposure apparatus that transfers an original pattern onto a substrate.

Claims (12)

An aperture device that defines an aperture of an optical system by a plurality of light shielding blades that overlap each other,
Each shading feather includes a linear contact portion having a contact surface that comes into contact with an adjacent member adjacent to the shading feather,
A diaphragm device characterized by that. The adjacent member is another shading feather,
The diaphragm device according to claim 1. In the contact portion, at least a portion of the contact surface that can come into contact with the other light-shielding blade in the adjustment of the opening by driving the plurality of diaphragm blades belongs to one plane.
The diaphragm device according to claim 2. The contact surface of the light shielding wing is formed by the surface of a film covered with the base material of the light shielding wing, and the friction coefficient of the surface of the film is smaller than the friction coefficient of the surface of the base material,
The diaphragm apparatus according to claim 2 or 3, wherein The shading wing has the contact portion on the first surface and the second surface facing the other two shading wings,
The diaphragm apparatus according to any one of claims 2 to 5. The linear contact portion of each light shielding feather intersects the linear contact portion of the light shielding feather adjacent thereto,
The diaphragm apparatus according to any one of claims 2 to 5. A plurality of the contact portions are arranged;
The diaphragm device according to any one of claims 2 to 6, wherein The plurality of contact portions are arranged concentrically,
The diaphragm apparatus according to claim 7. The contact portion has a linear shape,
The diaphragm device according to any one of claims 2 to 7, wherein: The contact portion has a curved shape,
The diaphragm device according to any one of claims 2 to 7, wherein:   An optical system in which the diaphragm device according to any one of claims 1 to 10 is incorporated.   An exposure apparatus comprising an optical system in which the aperture device according to any one of claims 1 to 11 is incorporated, and configured to transfer a pattern of an original to a substrate.