JPS62161533A - Manufacture of plastic lens and so on - Google Patents

Abstract

PURPOSE:To achieve the manufacture of a fine lens, etc. capable of easy mass production by a method in which after a substrate has been coated with electron beam resist, the specified pattern of a lens is described on said resist by electron beam describing process, and the resist is developed, and then while using the residual film resist on this substrate as a male mold, the female mold molded by electroforming process is used for producing the lens. CONSTITUTION:The surface of a substrate 1 is uniformly coated with electron beam resist 2a, and electron beam 3 is directed to this resist 2a by an electron beam describing device, whereby a specified lens-malemold pattern is described. When the resist 2a is developed, the female mold pattern 2b for the specified lens out of the residual film resist remains on the substrate 1. Gold is deposited on the substrate 1 with the residual film resist 2b, thereby forming an electrode layer 4, and then chrome plated layer 5 is provided on said layer. If the residual film resist 2b and if necessary the substrate 1 are removed by resolution, the female mold composed of the electrode larger 4 and the plated layer 5 remains. A plastic lens 6 is manufactured by injection molding, using this female mold.

Description

DETAILED DESCRIPTION OF THE INVENTION Background of the Invention The present invention relates to a method for manufacturing plastic lenses and the like using electron beam lithography.

Conventionally, single-spherical glass lenses have been used as lenses for micro-optical systems used in optical pickups, etc., but in order to eliminate the aberrations unique to single-spherical lenses, it is necessary to combine multiple lenses. Protection? ! High precision was required for j, and it was inevitable that the optical system itself would become larger.

A plastic aspherical lens that replaces a spherical glass lens, a Fresnel lens in plastic, is manufactured by injection molding using a mold, but the mold is made by cutting. It is extremely difficult to process a mold for a microlens with an aperture diameter of 1 mm or less according to its theoretical shape.

Summary of the Invention In view of the above, the present invention is relatively easy and mass-producible.
1. To provide a method for manufacturing microlenses etc. that are capable of rJ.
target

The method for manufacturing plastic lenses, etc. according to this invention is as follows:
! An electron beam resist is applied onto the board, and a predetermined pattern such as a lens is drawn on this resist-1- by electron beam drawing method.The resist is then developed, and the remaining film resist pattern on this substrate is used as a male pattern and exposed to electricity. Form a female mold by casting method,
A feature is that this "-ut type" is used to manufacture plastic lenses and the like.

This invention takes advantage of the fact that the residual film rate of the resist after development on the substrate depends on the amount of electron beam irradiation, so that the residual film of the resist on a desired lens pattern can be formed with different strengths or amounts depending on two positions. It is fabricated by irradiating it with an electron beam. Then, the resist remaining film pattern formed by the difference in the resist remaining film rate after development depending on the location is used as a male mold and plated with metal, and then the remaining film pattern is dissolved with a solvent or the like to form a metal female mold. to make. This female mold can be used to make microscopic plastic lenses, such as plastic blazed Fresnel lenses, by injection molding or other methods.

According to the method for manufacturing lenses and the like according to the present invention, since the electron beam irradiation aperture and the drawing position can be controlled by a computer in the electron beam drawing device, an ideal lens without aberration can be created.
A pattern is obtained. Since a lens having a flat plate shape and sufficient performance can be obtained with a single lens, it is possible to construct a compact lens system that does not take up much space. Processes such as polishing can be omitted and manufacturing is easy. Since it can be made by molding plastic, it is suitable for mass production. The lens shape is determined by computer
Since it is determined by software, the shape can be changed and improved freely, resulting in high flexibility.

This invention can be applied to the production of gratings and the like in addition to lenses.

DESCRIPTION OF THE EXAMPLE This example creates a Fresnel lens.

In FIG. 1, substrate 1. For example, an electron beam resist 2a, such as CMS-EX(R) (negative resist), is uniformly applied to the Si surface, and an electron beam 3 is irradiated onto the resist 2a by an electron beam lithography device to form a predetermined lens. A male pattern is drawn (FIG. 1(A)). When this resist 2a is developed, a predetermined lens male pattern 2b remains on the JJ plate 1 due to the residual film resist (FIG. 1(B)). For electron beam resists, when the amount of electron beam irradiation is controlled depending on the location, the thickness of the film that remains after development changes depending on the irradiation amount and depending on the location.

The electron beam lithography apparatus is controlled by a computer, and can arbitrarily change the amount of electron beam irradiation for each coordinate position determined on the substrate. Also.

The change pattern can also be freely determined or selected by software.

The electrode layer 4 is formed by applying gold to the substrate 1''2 having the residual film resist 2b of the predetermined lens male pattern formed in this way (FIG. 1(C)). Further, plating layer 5 is created by plating chromium on 1- (first
Figure (D)). The gold electrode layer 4 formed by vapor deposition is used as an electrode when performing plating processing, and its thickness is several tens of angstroms F7 degrees, and the plating layer 5 is a few microns thick because it is used as a female mold for injection molding. The above is preferable. remaining film resist 2b, and Si substrate 1 if necessary
If it is removed by dissolving it with an organic solvent, etching solution, etc.,
A female mold consisting of electrode layer 4 and plating layer 5 remains.

A plastic lens 6 is manufactured by injection molding using the female mold thus formed (Fig. 1(E)).
).

There may be several ways to mold the plastic lens 6 using the female mold 5 (which also includes the electrode layer 4, but is designated by the reference numeral 5 for convenience). For example, as shown in Figure 2 (A),
Gold with four parts 10a! ! ! Female type 5 in four parts 1 Oa of 10
The lens 6
I can do it.

In addition, using two split molds If, 12, one of the split molds 11
The -Ut mold 5 is placed in the four parts 11a of the mold 5, and the two molds 11 and 12 are joined facing each other. And the four parts 12a of the split mold 12
Inject resin inside.

Finally, as an example, the male pattern of a Fresnel lens, that is, the residual resist pattern, will be quantitatively explained.

The male pattern shape of the Fresnel lens (Fresnel lens pattern shape) F (r) is expressed by the following equation.

F(r)−d− (d/2 π) ・l[(πr 2)haλf )](
mod2 yr )1d -λ/(n-1) However.

r; Distance from the center of the lens d: Thickness of the lens λ; Wavelength of light incident on the lens f: Focal length of the lens n: Refractive index of the lens constituent material This shape F (r) is the thickest in Figure 3 Indicated by a solid line.

Using the above formula, the relationship between the distance r from the lens center and the electron beam irradiation time D (r) is as follows:
When the probe current is 1.3×10 A, it is expressed as linear.

D (r) −2,75x tO,8−[C0,8r 2) / (2λf)](
sod O,8)+1.4 If the resist is irradiated with an electron beam and developed according to this formula, a resist film with a male Fresnel lens pattern will remain on the substrate.

The explanation of -1- is for a negative resist.

It goes without saying that the present invention can also be practiced by using a positive resist.

[Brief explanation of drawings]

Figures 1 (A) to (E) are process diagrams for sequentially explaining the steps of carrying out the method of the present invention, and Figure 2 (A)
and (B) are cross-sectional views showing an example of a plastic lens molding process, and FIG. 3 is a diagram showing a male pattern of a Fresnel lens. 1...Substrate, 2a...Resist. 2b...Resist pattern (male type). 3... Electron beam, 4... Electrode layer. 5... Plating layer (female type). 6...Plastic lens. Above Figure 1 (A) (D) (E) Figure 2

Claims (1)

[Claims] An electron beam resist is applied onto a substrate, a predetermined pattern such as a lens is drawn on the resist using an electron beam drawing method, and then the resist is developed to remove the remaining film resist pattern on the substrate. A method for manufacturing plastic lenses, etc., in which a female mold is formed by electroforming as a mold, and this female mold is used to manufacture plastic lenses, etc.