JPH063506A - Production of lens and production of lens array plate - Google Patents

Abstract

PURPOSE:To enable the easy production of fine lenses of a sheet form or a fine array plate of a large area with good accuracy and to obtain the distributed index lens with excellent mass productivity by subjecting the photosensitive refractive index control agent of a transparent base material by irradiation with a laser beam having a light intensity distribution. CONSTITUTION:A transparent substrate 1 contg. the photosensitive refractive index control agent is irradiated with the laser beam having the light intensity distribution, by which the refractive index control agent is fixed into the transparent material 1. Then, the fixing amt. of the refractive index control agent is provided with partial differences in accordance with the light intensity distribution of the laser beam, by which a refractive index distribution is formed. The light intensity distribution usually indicates a gauss distribution in such a case and, therefore, the lens region continuously varying in the refractive index in accordance with the gauss distribution is formed. The distribution state of the refractive index is arbitrarily controllable by the irradiation quantity of the laser beam having the light intensity distribution or by scanning therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a gradient index lens which is excellent in mass productivity of fine lenses, and a method of manufacturing an array plate of such a lens.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a gradient index lens, a method of depositing a lens forming material while changing the composition inside a cladding forming tube, and a method of changing the refractive index from the outer circumference of a rod-shaped lens A method of impregnating a substance,
A method has been known in which the modified refractive index monomer is volatilized from the outer periphery of the resin matrix containing the modified refractive index monomer, and the residual monomer is polymerized.

However, in any of the methods, it is difficult to obtain a lens in a sheet form, and it is also difficult to directly form a small lens having a small diameter and a short dimension. First, a preform is formed and then it is heated and stretched. It is necessary to perform wire drawing by a method etc., cut out a small-diameter body of the required size from that, and shorten both sides while polishing both sides. Therefore, complicated and complicated work is required to form a fine lens, and mass productivity is poor. There was a problem. There is also a problem that it is difficult to control and adjust the refractive index distribution.

On the other hand, in order to obtain a lens array plate, it is necessary to bundle and fix the small diameter bodies with a clad layer having the above-mentioned necessary dimensions, and to reduce the thickness while polishing both sides, which is not suitable for mass production, and the clad layer is required. The aperture ratio is restricted and it cannot be increased, and the circular lens cross-section is variously deformed when the array is made finer. Even if the cross-section can be made hexagonal, There was a problem that the efficiency was lowered and it was difficult to manufacture a large area plate.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to a graded-index lens that can easily manufacture sheet-shaped fine lenses and a large-area fine array plate with high array accuracy and is excellent in mass productivity. The task is to develop a manufacturing method.

[0006]

According to the present invention, a transparent base material containing a photosensitive refractive index adjusting agent is irradiated with a laser beam having a light intensity distribution to a necessary portion of the transparent base material so that the refractive index adjusting agent is transparent to a transparent group. The present invention provides a method for manufacturing a lens or a lens array plate, which is characterized in that it is fixed in a material.

[0007]

[Function] By irradiating a laser light having a light intensity distribution to fix the photosensitive refractive index adjusting agent in the transparent substrate, the fixing amount of the refractive index adjusting agent can be determined based on the light intensity distribution of the laser light. It is possible to make a partial difference so that a refractive index profile can be formed. In that case, since the light intensity distribution of the laser light usually exhibits a Gaussian distribution,
A lens region whose refractive index continuously changes can be formed based on the Gaussian distribution. Therefore, it is important to give the light intensity distribution to the irradiation light, and even if the uniform intensity light is applied through the binary optical mask consisting of the exposed part and the non-exposed part, it has the target refractive index distribution. I can't let you.

In the above, the distribution state of the refractive index can be arbitrarily controlled by the irradiation amount of the laser light having the light intensity distribution and the scanning, and the irradiation amount is the irradiation time, the beam position of the laser light,
It can be adjusted according to the size of the irradiation spot. Further, whether to increase or decrease the refractive index in the radial direction of the lens depends on the selection of the refractive index adjusting agent to be used, that is, to use or to increase the refractive index of the transparent substrate. Can be controlled by using.

Therefore, according to the above method, the lens or the array plate thereof can be formed by irradiating the transparent substrate with the laser beam, which is excellent in mass productivity and is easy to manufacture a large area plate. In addition, since it is easy to form uniform lenses regularly, the lenses can be arrayed with high precision, and irradiation through an optical mask provided with a non-exposed portion is not required, so that the lenses can be arranged in high density. Arrangement can be achieved and a large aperture ratio can be obtained.

[0010]

EXAMPLES In the production method of the present invention, a transparent base material containing a photosensitive refractive index adjusting agent is irradiated with laser light having a light intensity distribution to fix the refractive index adjusting agent in the transparent base material. The single lens as illustrated in FIG. 1 or the lens array plate as illustrated in FIG. 2 is appropriately formed by controlling the irradiation position of the laser light. In the figure, 1 is a transparent substrate, and 2 is a formed lens portion.

The transparent base material containing the photosensitive refractive index adjusting agent used in the present invention comprises at least one kind of a photoreactive substance made of an appropriate material such as a monomer, an oligomer, a resin, glass and other inorganic substances. When used in combination, the refractive index adjusting agent composed of the photoreactive substance is fixed by irradiation of laser light, so that a material exhibiting transparency to wavelength light when used as a lens is formed. Anything you have done is fine.

As a generally used transparent substrate containing a photosensitive refractive index adjusting agent, a photopolymerizable monomer or a photopolymerizable monomer having a different photopolymerizability is used in a base material composed of a polymer, glass, an inorganic crystal or a composite thereof. Examples thereof include those containing a refractive index adjusting agent composed of one or more kinds of monomers and photosensitive glass. The transparent substrate may also contain a photoreaction initiator, a photosensitizer, etc., if necessary.

As the transparent base material, an appropriate base material that is transparent to wavelength light when used as a lens can be used, but such base material does not have to be solid at the stage of irradiation with laser light. Alternatively, it may be solidified by an appropriate treatment such as heat treatment or exposure treatment after laser light irradiation. The thickness of the transparent substrate may be appropriately determined according to the desired lens effect and the like, and is generally 10 μm to 10 mm.

The above-mentioned photopolymerizable monomer and photosensitive glass exemplified as the refractive index adjusting agent are those which are fixed by polymerization, curing, addition, compounding, etc. through irradiation of laser light with each other or through the base material. However, in the present invention, the type of fixing is not particularly limited as long as it is not easily separated from the substrate. If necessary, the fixing state can be reinforced by developing treatment, heat treatment, pre-exposure treatment, post-exposure treatment, solvent treatment and the like.

Therefore, as the photosensitive refractive index adjusting agent, the refractive index which changes depending on the irradiation intensity of the laser light, for example, the degree of polymerization, the rate of polymerization, the degree of curing, the degree of crosslinking, the change (distribution) of the addition rate, etc. Any suitable material that forms a state may be used.

As described above, in the present invention, the change (distribution) of the refractive index in the formed lens is given by the change in the fixing amount of the refractive index adjusting agent, which is applied by irradiation with laser light having a light intensity distribution. By.

For the irradiation of laser light, an appropriate laser oscillator can be used according to the reaction wavelength of the refractive index adjusting agent and other photoreactive materials such as photopolymerization initiators and photosensitizers.
Preferably, it is possible to form a circular beam cross section and exhibit a 0th-order or 1st-order Gaussian distribution as the light intensity distribution. A preferable irradiation wavelength of laser light is 200 to 650.
nm, and therefore an ultraviolet laser or the like can be preferably used.

Examples of commonly used laser oscillators include those that oscillate a laser beam having a relatively short wavelength, such as an excimer laser, an argon laser, or a helium / cadmium laser. Depending on the combination of the photopolymerization initiator and the photosensitizer, a helium / neon laser may be used. Further, a long-wavelength laser such as a YAG laser may be wavelength-converted into, for example, a third harmonic and used.

FIG. 3 exemplifies a manufacturing apparatus in which a laser oscillator is arranged. This is a laser oscillating unit 3, a shutter 4, a condenser unit 5 including a lens, a mirror, a filter, and the like.
The scanning optical system 6 is composed of a mirror and the like.

Irradiation of the laser beam (arrow) to the transparent substrate 1 is performed by condensing the laser beam oscillated by the laser oscillating section 3 through the condensing section 5 and adjusting the size of the irradiation spot. This can be performed by reflecting the light toward the transparent substrate side via the scanning optical system 6. The irradiation position and the scanning locus are adjusted by the control of the scanning optical system 6. The shutter 4 is for controlling the passage of the laser light oscillated by the laser oscillator 3 to the condensing unit 5. It is preferable that the shutter can be controlled in conjunction with the condensing unit and the scanning optical system. . The control can be easily performed by a device such as a personal computer.

The lens area to be formed is controlled, for example, by controlling the irradiation time and intensity of the laser beam, the beam position of the laser beam, the size of the irradiation spot, intensity control such as dimming with a filter or a transmittance distribution type optical mask, and scanning. It can be done according to the route and speed. In the present invention, it is possible to form a region having a smooth curve based on a Gaussian distribution or the like, in which the refractive index continuously changes, by irradiating for a predetermined time without scanning, or it is possible to scan with a laser beam to arbitrarily It is also possible to form a large lens area. In that case, the size of the irradiation spot is usually about 0.01 to 200 mm.

In the above-mentioned scanning method, a region in which the changing portion of the refractive index is continuous is formed according to the scanning path. In that case, the irradiation amount per unit distance can be adjusted by controlling the converging degree of the laser light or by the scanning speed, and thereby the width of the region where the refractive index changes formed in the scanning path can be controlled. Then, usually, portions where the refractive index continuously changes are formed on both sides thereof along the scanning direction. Therefore, when the scanning paths are crossed or overlapped, a portion having a refractive index different from that of the other scanning portions can be formed in the overlapped portion.

The form of the lens formation region by the irradiation of laser light is arbitrary. The lens region may occupy the entire transparent base material, or may occupy only a part thereof, or may be formed as a plurality of regions to form an array of lenses. The shape, diameter, thickness, focal length, etc. of the lens to be formed are arbitrary, and the surface shape of the lens is, for example, planar, convex, concave, or a combination thereof. Even when the lenses are arrayed, the form, the arrangement state, and the arrangement number of the lenses are arbitrary. The closest packing is more advantageous than the aperture ratio. The diameter of a general lens unit formed as a single lens or a lens array plate is 0.01 to 2
It is about 00 mm.

The distribution state of the refractive index in the lens can be appropriately determined according to the purpose of use and the shape of the lens surface.
In the case of a planar lens, a quadratic curve distribution with the lens center as the apex is usually preferable from the viewpoint of transmission. In that case, by making the apex maximum, it can be a lens that acts like a convex lens, and by making it a minimum, it can be a lens that acts like a concave lens. Further, a lens that acts like an aspherical lens can be obtained by adjusting the refractive index distribution. The magnitude of the refractive index in the lens and the magnitude of the refractive index difference in the distribution are appropriately determined by the diameter and thickness of the lens, the performance, and in the case of the lens array plate, the distance between the nearest lenses.

After the fixing process of the refractive index adjusting agent by the irradiation of the laser beam is completed, it remains in the transparent substrate as one of the developing process, the heating process, the exposure process, the solvent process, etc., if necessary. The unfixed refractive index adjusting agent is removed. Such a removal treatment can be performed by an appropriate method such as an extraction treatment with a solvent or a volatilization treatment by heating, depending on the contained refractive index adjusting agent.

The lens and lens array plate according to the present invention are
It can be used for various purposes. In particular, the array plate of fine lenses can be preferably used for improving the visibility of the liquid crystal display device or improving the display. That is, by extracting only the light rays that have passed through the liquid crystal panel of the liquid crystal display device and travel in various directions through the lens array plate through the liquid crystal layer vertically or at an angle close thereto, the contrast decreases depending on the viewing angle. It is possible to obtain a good display by suppressing the inversion of the display, the change of the hue, and the like.

Example 1 10 parts of polymethyl acrylate obtained by solution polymerization (parts by weight, the same applies hereinafter), 10 parts of tribromophenoxyethyl acrylate (refractive index improving type, refractive index 1.56) and 20 parts of ethyl acetate. Photopolymerization initiator (Irgacure 6
51, manufactured by Ciba-Geigy Co., Ltd., the same applies hereinafter) and mixed with 0.1 part and developed by a normal casting method to obtain a thickness of 10
A film of 0 μm is formed, and while irradiating with an argon laser at a spot diameter of 500 μm for 100 ms per spot, it is immersed in methanol to extract and remove unreacted tribromophenoxyethyl acrylate, and a lens array plate is formed. Obtained. The diameter of each circular lens portion formed was about 0.6 mm, and the pitch between the lens centers was about 0.62 mm.

Example 2 A lens array plate was obtained in the same manner as in Example 1 except that trifluoroethyl acrylate (refractive index decreasing type, refractive index 1.3) was used instead of tribromophenoxyethyl acrylate.

Example 3 500 μm thick bifunctional urethane acrylate type cured sheet (Unidick 15-829, manufactured by Dainippon Ink and Chemicals, Inc.)
Was impregnated with a solution prepared by dissolving 10 parts of tribromophenoxyethyl acrylate and 0.1 part of a photopolymerization initiator in 10 parts of chloroform, and then the chloroform was removed in a dark place, and the sheet was prepared according to Example 1. A lens array plate was obtained by irradiating laser light.

Comparative Example The tribromophenoxyethyl acrylate-impregnated sheet obtained according to Example 3 had 80 exposed parts with a diameter of 500 μm.
The lens array plate was obtained by irradiating ultraviolet rays through an optical mask formed in a closest packed state at intervals of 0 μm (non-exposed portion) to extract and remove unreacted tribromophenoxyethyl acrylate.

Evaluation Test The refractive index distributions of the lens units in the lens array plates obtained in Examples and Comparative Examples were measured with a differential interference microscope (Carl Zeiss Jena). The above results are shown in FIG.
It was shown to.

It can be seen from FIG. 4 that the refractive index changes almost continuously in the example. On the other hand, in the comparative example, it can be seen that the change in the refractive index is stepwise. Further, by visually observing the light rays that have passed through the lens array plate, it has been confirmed that each lens portion exhibits good optical characteristics of a convex lens type in Examples 1 and 3 and a concave lens type in Example 2.
However, the lens effect could not be recognized in the comparative example.

[0033]

According to the present invention, since the laser light method is used, it is possible to easily mass-produce a gradient index fine lens or an array plate thereof, and it is possible to easily manufacture a sheet-shaped large area plate. In addition, lenses having excellent shape uniformity can be accurately arrayed, and an array plate having a large aperture ratio can be obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective explanatory view illustrating a lens.

FIG. 2 is a partial cross-sectional perspective view illustrating a lens array plate.

FIG. 3 is an explanatory diagram of a manufacturing apparatus.

FIG. 4 is a graph showing a refractive index distribution state.

[Explanation of symbols]

 1: Transparent base material 2: Lens part 3: Laser oscillator 4: Shutter 5: Focusing part 6: Scanning optical system

Claims (2)

[Claims] 1. A lens characterized in that a transparent substrate containing a photosensitive refractive index adjusting agent is irradiated with laser light having a light intensity distribution to fix the refractive index adjusting agent in the transparent substrate. Manufacturing method. 2. A transparent base material containing a photosensitive refractive index adjusting agent is irradiated with laser light having a light intensity distribution to fix the refractive index adjusting agent in the transparent base material. And a method for manufacturing a lens array plate.