JP2001100427A - Exposure method for curved surface and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the easy exposure of a curved surface. SOLUTION: The light transmitted through a flat plate mask 2 is reflected by a conical mirror 3 of a recessed shape and is cast to the curved surface of a work 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for exposing a curved surface such as a rod or a tube.

[0002]

2. Description of the Related Art In the exposure of a curved surface such as a rod or a tube, a normal exposure method for a flat surface cannot be applied. For example, as shown in FIG. Then, the work 1 is rotated by the step rotation to perform the exposure.

[0003]

However, the above-described exposure has a drawback that the exposure time per surface, that is, the entire exposure time becomes longer. Further, the mask is flat, but the surface to be exposed has a curved surface, so that accurate exposure cannot be performed.

[0004] It is conceivable that the mask itself is also curved, but accurate exposure is not achieved unless incident light is incident on all portions of the curved surface from the normal direction. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for eliminating the above-mentioned drawbacks and easily exposing the curved surface.

[0005]

According to the exposure method of the present invention, light passing through a flat mask is reflected by a concave conical mirror to expose a curved surface of a work. Thus, the exposure of the curved surface can be easily and collectively performed using the flat mask. In particular, when forming a dynamic pressure groove on the radial surface of the dynamic pressure bearing, light passing through the flat mask is reflected by a concave conical mirror to expose the radial surface.

[0006] This makes it possible to easily and collectively expose the radial surface of the dynamic pressure bearing using a flat mask. The angle of the concave conical mirror is 45 degrees. This simplifies the design of the device. Further, a projection lens system is provided between the mask and the concave conical mirror.

As a result, a highly accurate pattern can be exposed on the resist surface even if the mask is separated from the resist. Alternatively, a reflection optical system is provided between the mask and the concave conical mirror.
Thereby, even if the mask and the concave conical mirror are separated, a highly accurate pattern can be exposed on the resist surface.

In the exposure apparatus according to the present invention, the light having passed through the flat mask is reflected by a concave conical mirror to perform exposure on a curved surface. Thus, the exposure of the curved surface can be easily and collectively performed using the flat mask. In particular, in the exposure device for the radial surface of the dynamic pressure bearing, the light that has passed through the flat mask is reflected by a concave conical mirror to expose the radial surface.

Thus, the exposure of the radial surface of the dynamic pressure bearing can be easily and collectively performed using the flat mask.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an exposure method of the present invention. The light that has passed through the flat mask 2 is reflected by the concave conical mirror 3 and is applied to the curved surface of the work 1.

A resist for etching or plating is formed on the work in advance. FIG. 2 is a view showing another exposure method of the present invention. In this case, the angle of the concave conical mirror is 45 degrees, so that the angle between the incident light and the reflected light is 90 degrees, and the light is incident from the normal direction of the curved surface, so that the pattern accuracy is improved and the design and structure of the device are simplified. .

Even if parallel light is used, light that has passed through the mask causes diffraction, so that measures must be taken. When the distance between the mask and the resist is increased, it is necessary to take measures against the diffraction effect. FIG. 3 is a view showing another exposure method of the present invention. The pattern of the flat mask 2 is reflected by the concave conical mirror 3 by the projection lens 4 and projected on the radial surface.

Thus, even if the mask is separated from the resist, a highly accurate pattern can be exposed on the resist surface. The projection lens includes a reduction type and a unity type. The reduced type has a narrow field of view, and the unity type requires monochromatic light to reduce aberration. FIG. 4 is a view showing still another exposure apparatus of the present invention.

The pattern of the flat mask 2 is reflected by the concave conical mirror 3 from the reflection optical system 5 through the slit 9 and projected on a radial surface. When projection exposure is performed by such a reflection optical system, chromatic aberration does not occur and exposure with higher accuracy can be performed. FIG. 5 is a view showing an example of a dynamic pressure bearing component, which has a structure in which a rod-shaped radial bearing 7 having a radial surface is fitted into a disk-shaped thrust bearing 6 having a thrust surface. A dynamic pressure groove 8 having a shape called a herringbone is formed on the surface.

In addition to the above, there are several modified types such as a configuration in which a radial bearing and a thrust bearing are constituted only by a ring-shaped disc portion and a configuration in which a rod-shaped radial bearing is separated.
The shape of the dynamic pressure groove may be not only herringbone but also spiral. When the dynamic pressure grooves of the dynamic pressure bearing are formed by a photo-etching method or a plating method, the exposure of the photoresist is performed on the radial bearing as shown in FIG.
Is reflected by the concave conical mirror 3.

This makes it possible to easily collectively expose the radial surface, which has been conventionally difficult. At this time, the angle of the concave conical mirror is set to 45 degrees as shown in FIG. Alternatively, if the projection optical system is used as shown in FIGS. 3 and 4, exposure with higher accuracy can be performed, as described above.

[0017]

As described above, according to the method and apparatus of the present invention, exposure of a curved surface can be easily performed.

[Brief description of the drawings]

FIG. 1 is a view showing an exposure method of the present invention.

FIG. 2 is a view showing an exposure method of the present invention.

FIG. 3 is a view showing an exposure method of the present invention.

FIG. 4 is a view showing an exposure method of the present invention.

FIG. 5 is a view showing a dynamic pressure bearing part.

FIG. 6 is a view showing a conventional exposure method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Work 2 ... Plate mask 3 ... Conical mirror 4 ... Projection lens 5 ... Reflection optical system 6 ... Thrust bearing 7 ... Radial bearing 8 ... Dynamic pressure groove 9 ···slit

Claims (7)

[Claims] 1. A method of exposing a curved surface, comprising the step of exposing a curved surface by reflecting light having passed through a flat mask with a concave conical mirror. 2. The exposure method according to claim 1, wherein the curved surface is a radial surface of a dynamic pressure bearing. 3. The method according to claim 1, wherein the concave conical mirror forms an angle of 45 degrees. 4. A method according to claim 1, further comprising a projection lens system between said flat mask and said concave conical mirror. 5. A method according to claim 1, wherein a reflection optical system is provided between said flat mask and said concave conical mirror. 6. An exposure apparatus having a curved surface, wherein light having passed through a flat mask is reflected by a concave conical mirror to perform exposure. 7. An exposure apparatus according to claim 6, wherein said curved surface is a radial surface of a dynamic pressure bearing.