JP2002029762A - Method for manufacturing fly eye lens and device for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a fly eye lens with high precision and excellent mass productivity. SOLUTION: In this method for manufacturing a fly eye lens by heating and pressurizing a plate-shaped lens material 8, the lens material is set on a female mold/carrying tray plate 6 arranged so as to be available as both a female mold and a carrying tray, and the lens material is pressurized between a male mold 22 and the female mold/carrying tray plate while the lens material is heated. Thus, the fly eye lens can be manufactured with high precision and high mass productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for manufacturing a fly-eye lens made of, for example, glass.

[0002]

2. Description of the Related Art In general, in the photolithography technique for transferring a fine pattern of an integrated circuit onto a substrate such as a semiconductor wafer by the principle of photography, illumination of uniform brightness without unevenness is performed over the entire mask surface. For this purpose, for example, a fly-eye lens is used. Since the fly-eye lens can obtain uniform brightness over a wide surface as described above, it is also used in the field of an illumination optical system of a liquid crystal projector. Conventionally, this fly-eye lens has been manufactured by a known direct press molding method,
It has been manufactured by a method of reheating and heating glass as disclosed in Japanese Patent No. 44842/44.

[0003]

In the direct press molding method described above, not only the accuracy of the lens shape is as low as about 30 Newton rings, but also the shape of the rear surface (flat surface) of the lens after molding. There has been a problem that the process is complicated, such as a need for polishing to increase the accuracy. On the other hand, the reheat pressure molding method is
The shape accuracy is high, and there is an advantage that the polishing process for improving the accuracy after molding is not required, but the upper mold and the lower mold are allowed to cool down to a predetermined temperature each time press molding is performed in a heated state. After that, since it is necessary to take out the completed fly-eye lens, it takes a long time to produce one fly-eye lens, which is inferior in mass productivity. The present invention has been made in view of the above problems, and has been made in order to solve the problems effectively. An object of the present invention is to provide a method for manufacturing a fly-eye lens which is highly accurate and excellent in mass productivity. And a manufacturing apparatus therefor.

[0004]

The invention according to claim 1 is
In a method of manufacturing a fly-eye lens by pressing and molding a plate-shaped lens material while heating, the lens material is placed on a lower mold / transport tray plate that also serves as a lower mold and a transport tray, and the lens material is provided. Is pressed between the upper mold and the lower mold / transport tray plate in a heated state. Thus, after the fly-eye lens is formed by press-molding the lens material, it is possible to convey the fly-eye lens without placing the fly-eye lens on the tray plate without cooling the upper and lower mold / transport tray plates. Therefore, it is possible to immediately shift to the next pressure forming operation, and thereby it is possible to improve the accuracy and the mass productivity.

[0005] The invention according to claim 2 is an apparatus for carrying out the above method invention. More specifically, an apparatus for manufacturing a fly-eye lens from a plate-like lens material by pressure molding includes a lower mold and a lower mold. A lower mold / transport tray plate also serving as a transport tray, an upper mold having a molding surface opposite in shape to the lens surface of the fly-eye lens, and joining and separating the lower mold / transport tray plate and the upper mold And a die actuator for producing the fly-eye lens.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and apparatus for manufacturing a fly-eye lens according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a plan view showing a fly-eye lens, FIG. 2 is a side view of the fly-eye lens, FIG. 3 is a cross-sectional view showing a lower mold and transport tray plate, and FIG. . First, as shown in FIGS. 1 and 2, the fly-eye lens 2 is manufactured by heating and press-molding a lens material made of, for example, a plate-like glass plate, for example, white plate glass, as described later. A large number of quadrangular convex lens elements 4 are arranged in the vertical and horizontal directions on the surface of the fly-eye lens 2 to constitute a lens assembly. The dimension of this one lens element 4 is such that the vertical length H1 is set to 5 mm and the horizontal length H2 is set to 7 mm, and the convex portion has a spherical shape with a radius of about 36 mm.

On the other hand, as shown in FIG. 3, a lower mold and transfer tray plate 6 is provided with a lower mold at the time of pressure molding and a glass plate-like lens material 8 used as a material of the fly-eye lens 2. It has both functions as a transport tray for transporting the paper, and a mounting surface 10 formed in a concave shape is formed on the upper surface thereof. A support frame 12 is provided detachably around the mounting surface 10 to facilitate removal of the fly-eye lens 2 after molding. The lower mold / transport tray plate 6 can be formed of carbide, glassy carbon, heat-resistant steel, or the like, and the mounting surface 10 which is the contact surface with the lens material 8 is mirror-finished. . Immediately after the heat and pressure molding of the lens material 8, the lower mold / transport tray plate 6 and the fly-eye lens 2 made of glass are used.
The term (8) indicates that the adhesive is firmly attached due to a so-called optical contact state, but this adhesion is released during the cooling process.

Next, an apparatus for manufacturing a fly-eye lens will be described with reference to FIG. This manufacturing apparatus 14 has a press chamber 16 which can be evacuated. An upper mold 22 having an upper heater 20 is provided on the ceiling of the press chamber 16 via a heat insulating material 18. This upper mold 22
Is formed in a shape opposite to the lens surface, which is an aggregate of the lens elements 4 of the fly-eye lens 2, so that an aggregate of a large number of concave portions is provided. At the bottom of the press chamber 16, a heat insulating material 26 is placed on a base 24.
The lower heater 28 is provided through the lower heater 28, and the lower die and transport tray plate 6 can be placed on the upper surface of the lower heater 28. The base 24 is attached to the upper end of a rod 32 of a mold actuator 30 composed of, for example, a hydraulic cylinder or the like, so that the lower die and transfer tray plate 6 can be moved up and down in a vertical direction so as to be press-pressed. Has become.

On the side wall of the press chamber 16, a preheating chamber 36, which can be evacuated, is joined via a gate valve 34 which can be opened and closed. In the preheating chamber 36, the cassette vertical drive unit 3 is provided.
8 is provided with a cassette table 42 which is connected to the rod 40 and is vertically movable. A vertically long cassette 44 is placed on the cassette table 42. In the cassette 44, the lower mold and transport tray plate 6 can be stored in multiple stages at a predetermined pitch. In the illustrated example, the fly-eye lens 2 after pressure molding and the tray plate 6 supporting the fly-eye lens 2 are indicated by dashed lines. And
A preheating heater 46 for preheating the lens material 8 installed on the lower mold and transport tray plate 6 is provided below the center of the preheating chamber 36 in the height direction and arranged vertically. Have been. A telescopic hand 48 is provided on the side wall of the preheating chamber 36 so as to extend into the press chamber 16 via the opened gate valve 34, and the cassette 44 and the press chamber 16 are extended.
The lower die and transfer tray plate 6 is transferred to and from the inside.

Next, a method of manufacturing a fly-eye lens performed using the manufacturing apparatus configured as described above will be described. First, a plate-shaped lens material 8 is placed on each lower mold and transport tray plate 6, a plurality of such tray plates 6 are accommodated in a cassette 44, and the cassette 44 is placed in a preheating chamber 36.
Is set on the cassette table 42 in the inside. Then, the inside of the preheating chamber 36 is evacuated to a predetermined pressure, and at the same time, each lower mold / transport tray plate 6 in the cassette 44 and the lens material 8 made of, for example, white plate glass installed in the lower tray can be molded. The temperature is raised to a predetermined temperature higher than 710 ° C., for example, 750 ° C., and preheated. At the same time, the interior of the press chamber 16 is also evacuated in advance, and the upper mold 22 therein is heated by the upper heater 20 to, for example, about 580 ° C., and the lower heater 28 is heated to about 670 ° C. Thus, the upper heater 20 and the lower heater 28
The reason for the temperature difference is that the lens material 8 has the property of firmly adhering to the mold on the higher temperature side. This is to make it possible to securely adhere. The reason why the temperatures of the upper mold 22 and the tray plate 6 are set lower than the temperature at which the lens material 8 can be molded is as follows.
This is because the lens material 8 is cooled at the same time as the pressing, and is cooled to a temperature at which the lens shape can be maintained in a shorter time.

In this state, the lower mold / transport tray plate 6 containing the unprocessed lens material 8 is held by the telescopic hand 48, and is held in the press chamber 16 via the gate valve 34 which is opened. It is carried in and placed on the upper surface of the lower heater 28. When the movement of the tray plate 6 is completed in this way, the mold actuator 30 is driven upward to bring the lower mold / transport tray plate 6 into press contact with the upper mold 22 to press-mold the lens material 8. I do. The pressing force at this time is, for example, a pressure of 100 kgf / cm ² and the pressing time is 1
It is about 0 seconds. As a result, the fly-eye lens 2 is formed from the lens material 8 by pressure molding. When the pressure molding is performed in this way, the lower mold and transfer tray plate 6 is immediately lowered to open the mold, and the telescopic hand 48 is expanded and contracted again to hold the tray plate 6 on the lower heater 28. Then, this is stored as processed in the cassette 44 in the preheating chamber 36. In FIG. 4, the tray plate 6 which has been processed as described above is indicated by a dashed line.

Subsequently, the tray plate 6 on which the second unprocessed lens material 8 is placed is held, and the lens material 8 placed thereon is subjected to pressure molding in the same procedure as described above.
Therefore, the upper mold 22 is continuously used in a heated state, and when the individual tray plates 6 have been subjected to pressure molding, they are immediately carried out to the preheating chamber 36 side without cooling. After all the lens materials 8 are continuously formed in this manner, the preheater 46 is turned off to cool the inside of the preheat chamber 36. After this cooling, with the gate valve 34 closed, air is introduced into the preheating chamber 36 to restore atmospheric pressure therein, and a door (not shown) is opened to take out the cassette 44. Then, the fly-eye lens as shown in FIGS. 1 and 2 is taken out by removing the lower mold / transport tray plate 6. Fly-eye lens 2 thus obtained
The production time per piece was about 10 minutes, and mass productivity was greatly improved. The accuracy of the convex surface of each lens element 4 of the fly-eye lens 2 is such that the surface roughness Ra is 5 nm or less, the variation of the spherical Newton ring is 2 or less, and the flatness on the plane side is 5 μm or less. Yes, all could be manufactured with high accuracy.

[0013]

As described above, according to the method and the apparatus for manufacturing a fly-eye lens of the present invention, the following excellent operational effects can be exhibited. After molding the fly-eye lens by pressure molding of the lens material, it is possible to carry the fly-eye lens with the fly-eye lens mounted on this tray plate without cooling the upper and lower mold / transport tray plates, so immediately It is possible to shift to the next pressure forming operation, whereby the accuracy and the mass productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a fly-eye lens.

FIG. 2 is a side view showing a fly-eye lens.

FIG. 3 is a cross-sectional view showing a lower mold and transport tray plate.

FIG. 4 is a configuration diagram showing an apparatus for manufacturing a fly-eye lens.

[Explanation of symbols]

2 ... Fly eye lens, 4 ... Lens element, 6 ... Lower mold / transport tray plate, 8 ... Lens material, 10 ... Placement table, 14 ... Fly eye lens manufacturing apparatus, 16 ... Press room, 20 ... Upper heater, 22 ... upper mold, 28 ... lower heater, 36 ... preheating chamber,
38: cassette vertical drive, 44: cassette, 46: preheater, 48: telescopic hand.

Claims (2)

[Claims] 1. A method of manufacturing a fly-eye lens by press-molding a plate-shaped lens material while heating the lens material, wherein the lens material is placed on a lower mold / transport tray plate which also serves as a lower mold and a transport tray. A method of manufacturing a fly-eye lens, characterized in that the lens material is pressure-formed between the upper mold and the lower mold and transport tray plate in a heated state. 2. An apparatus for manufacturing a fly-eye lens from a plate-like lens material by pressure molding, wherein a lower mold / transport tray plate serving also as a lower mold and a transport tray, and a lens surface of the fly-eye lens, An apparatus for manufacturing a fly-eye lens, comprising: an upper mold having a molding surface of an opposite shape; and a mold actuator for joining and separating the lower mold / transport tray plate and the upper mold.