KR20020038012A - Process for producing an article with a microstructure - Google Patents

Abstract

PURPOSE: A process of preparing a product of a microstructure having a relatively complicate microstructure pattern, excellent surface flatness and shape accuracy of a relatively high level is provided. Whereby, the product is able to be directly used or used for remanufacture of another product. CONSTITUTION: The product having a microstructure is prepared by the following steps: forming a first relief structure on the surface of a substrate; applying a photoresist on the substrate; exposing a part of the photoresist by the use of the photomask to form a microstructure pattern; and allowing an approach to a part of the first relief structure from the photoresist by generation of the microstructure pattern and then forming the surface having a microstructure relief shape connected to the exposed part of the first structure relief structure and the residue of the photoresist on the substrate.

Description

PROCESS FOR PRODUCING AN ARTICLE WITH A MICROSTRUCTURE}

The present invention relates to a method for manufacturing a product having a microstructure, in particular to the manufacture of a product having a microstructure with a relatively complex level of shape accuracy, with a relatively complex profile, and with a good surface flatness. It relates to a method of applying and to a product produced by the method.

Many methods can be used in the art for manufacturing products such as light transmitting plates having surfaces shaped into relief microstructures. The product was formed using a stamper or mold with an inverse pattern of relief microstructures. U. S. Patent No. 5,776, 636 shows a method for manufacturing a light transmissive plate, the method comprising forming a photoresist layer on a flat substrate, exposing the photoresist to form a deflection pattern in the photoresist. Generating an exposed photoresist to form a topographic relief in the photoresist corresponding to the deflection pattern, metallizing and electroforming the surface of the photoresist by forming a stamper; and Injection molding the light transmitting plate using a stamper. It is possible to expose the deflection pattern using parallel light beams irradiated on the photoresist layer penetrating the over-laid photo mask. In this case, the partial shape of the topographic relief is usually rectangular or trapezoidal. This also makes it possible to directly draw the pattern on the photoresist using the optical beam. In this case, the shape of the topographic relief can be altered by adjusting the exposure conditions and / or by adding a baking step between the steps of generating and metallizing. This is obtained by the procedures added in the method of making the light transmitting plate. In addition, it is difficult with the methods described above to form topographic reliefs with complex profiles and with good surface flatness and comparatively good levels of form accuracy.

It is therefore a main object of the present invention to provide a method for producing a product having a relatively complex microstructure pattern and a fine structure having good surface flatness and a comparatively good level of form accuracy, and a product produced by the method. It is to.

Thus, the method of the present invention involves forming a first relief structure on the surface of the substrate, applying a photoresist on the substrate, exposing a portion of the photoresist using a photomask to form a microstructure pattern. Step, allowing access to a portion of the first relief structure from the photoresist by generating a microstructure pattern in the exposed photoresist, and thereby thereby exposing the photoresist on the substrate and by the exposed portion of the first relief structure. Forming a surface shaped with microstructure relief bonded by the remainder, and a metal layer on the surface shaped to form a microstructured product with a profile corresponding to the microstructure relief on the shaped surface Configure the steps to form

Other aspects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings.

1 is a flow chart illustrating a process according to the invention,

2 (A) -2 (I) are perspective views illustrating a substrate formed of a concave first relief structure for use in the process of the present invention,

3 (A) -3 (D) are perspective views illustrating a substrate formed from a protruding first relief structure for use in the process of the present invention,

4 is a top plan view illustrating a substrate formed from a parallel set of linear relief structures substituted at equal distances from each other,

5 is a top plan view illustrating a substrate formed from a parallel set of straight relief structures displaced at different distances;

6 is a top plan view illustrating a substrate formed from the first and second sets of straight relief structures that intersect each other,

7 is a top plan view illustrating a substrate formed from a set of concentric relief structures,

8 is a top plan view illustrating a substrate formed from a set of curved relief structures,

9 is a cross-sectional view of the substrate shown in FIG. 2 (A),

10 is a cross-sectional view showing the substrate of FIG. 9 when a photoresist according to a first preferred embodiment of the method of the present invention is applied;

11 is a perspective view showing an exposure step of a first preferred embodiment process,

12 is a perspective view showing the result after the development stage of the first preferred embodiment process,

13 is a cross-sectional view of FIG. 12,

14 is a cross-sectional view showing the results after the metallization step of the first preferred embodiment process,

15 is a cross-sectional view showing the step of electroforming a metal product according to the first preferred embodiment process,

FIG. 16 is a perspective view illustrating a metal product formed in the step of FIG. 15;

17 is a perspective view showing the substrate of FIG. 2 (I) after a photoresist is applied according to a second preferred embodiment of the invention,

18 is a perspective view illustrating an exposure step of a second preferred embodiment process,

19 is a perspective view showing the results after the development stage of the second preferred embodiment process,

20 is a perspective view showing a stamper formed from a second preferred embodiment process, and

21 (A) -21 (F) show a third preferred embodiment process according to the present invention.

Before the present invention is described in more detail, it should be noted that the same elements are cited with the same reference numerals as they appear.

The method for producing a product having a microstructure according to the invention will now be described in more detail. 1 is a flow chart illustrating the process of the present invention.

The substrate is formed with the first relief structure on its upper surface. The first relief structure may be concave with respect to the upper surface of the structure or may protrude with respect to the upper surface of the substrate. The shape of the first relief structure is not limited. For example, the relief structure may be in the shape of concave portions 11a, 11b, 11c, 11d, 11e, 11f, 11g, 11h and 11i, as shown in FIGS. 2A-2I, or Alternatively, as shown in FIGS. 3A to 3D, the protrusions 11j, 11k, 11m, and 11n may be shaped. The first relief structure comprises a parallel set of linear structures that are evenly or unequally substituted from each other, as shown in FIGS. 4 and 5. In addition, the first relief structure, as shown in FIG. 6, is a second straight structure that intersects the parallel set of the first linear structure 11r and the first linear structure 11r. 11s) parallel sets. Alternatively, the first relief structure comprises a set of concentric circles 11t, as shown in FIG. The first relief structure also includes a set of disorderedly curved structures, as shown in FIG. 8.

The substrate is made from a material selected from the group consisting of metals, glass, ceramics and plastics. The substrate is the original workpiece, or a product formed from the original workpiece through one or more casting steps.

The first relief structure may be formed by cutting such as diamond cutting, drilling, milling or other known technique. When the first relief structure has good shape accuracy and good surface flatness, the microstructure obtained will similarly have a mirror surface evenly selected for good shape accuracy and good surface smoothness.

In a first preferred embodiment of the process according to the invention, the first relief structure is in the form of a hemispherical recess 11a shown in Fig. 2A. 9 and 10, after the first relief structure 11a is formed on the substrate 10a, the photoresist 20a is formed such that the surface of the photoresist 20a is formed on the upper surface of the substrate 10a. It is applied on the substrate 10a to fill the first relief structure 11a to be the same height. However, according to the present invention, this is not necessary for the photoresist 20a to be flush with the top surface of the substrate 10a.

Referring to FIG. 11, the photoresist 20a is then placed on the substrate 10a to form a microstructure pattern recorded as the first relief structure 11a in the direction transverse to the top surface of the substrate 10a. It is exposed using the covered photo mask 30a. The photo mask 30a is formed in a pattern according to requirements such as the size and distribution of the product microstructure to be manufactured. The photoresist 20a may be formed by spin coating, dip coating, roll coating, or the like through one or more process steps. Alternatively, the photoresist film can be formed in the present invention. There are positive and negative photoresists, and one of them can be used in the present invention.

After the exposure step, a microstructure pattern was generated in the exposed photoresist 20a, thereby allowing access to a portion of the first relief structure from the photoresist 20a, and thereby thereby as shown in FIGS. 12 and 13. And forms a surface that is shaped as a microstructure relief joined by the exposed portions of the first relief structure and by the remaining exposed portion 22a of the photoresist 20a on the substrate 10a. In the case where positive photoresist is used, the exposed portion 21a of the photoresist 20a is the remaining exposed portion of the photoresist 20a remaining on the substrate 10a as in this embodiment. It is removed during the generation step with 22a. Thus, in the negative photoresist, the unexposed portions are removed, where the exposed portions remain on the substrate.

After the generating step, the metal layer 40 is formed on the shaped surface to form the article with the agate structure in a profile corresponding to the microstructure relief on the shaped surface, as shown in FIG. 14. Metallization is performed using known techniques such as vacuum deposition, sputtering and the like. Then, as shown in FIG. 15, the metal product 50 is formed on the metal layer 40 by electroforming or non-electroplating. The metal product 50 is then stripped and has microstructure 51 in a profile opposite the microstructure relief on the shaped surface, as shown in FIG. 16. The metal product 50 is used directly as a light reflecting plate or a light diffusing plate, for example. Alternatively, the metal product 50 is used as a mold or stamper to reproduce the metal or plastic product by known casting or casting processes.

Since the first relief structure 11a on the substrate 10a can be formed into a good shape accuracy, good surface flatness, and a relatively complex shape by known diamond cutting techniques, and the microstructure on the metal product 50 Since 51 is transformed from one or more portions on the first relief substrate 11a, the microstructure 51 on the metal product 50 is manufactured by conventional methods such as etching, photo-lithography, and energy processing. Compared with those made, it can be made with better shape accuracy, better surface flatness and highly complex shape. Changes in the distribution of the microstructures 51 on the metal product 50 and in the size or length of the microstructures 51 are difficult to perform intermediate cutting and difficult to achieve using conventional processing methods such as diamond cutting.

Depending on the end use, such as for use as a master or stamper, the metal product 50 with the microstructure 51 may be trimmed to a suitable area or may plan its back portion by grinding or polishing.

If desired, multiple products can be formed by repeating the electroforming process using the metal product 50. Each of the products thus has a corresponding microstructure that is the opposite or opposite of the microstructure relief on the shaped surface.

The metal product 50 produced according to the invention is backlit in a liquid crystal display device for converting a point light source (such as a light emitting diode) or a line light source (such as a cold cathode fluorescent lamp) within a surface light source. It can be used as an illumination plate. It may be desirable for the light emitted from a surface light source largely related to shape to have good brightness and good uniformity, surface flatness and shape accuracy of the microstructures on the backlighting plate.

In a second preferred embodiment of the method according to the invention, the first relief structure 11i is in the form of a parallel set of elongated grooves having a V-shaped cross section as shown in FIG. 2 (I). The first relief structure 11i is formed on the substrate 10i by a known diamond cutting mechanism, and has good shape accuracy and good surface flatness. Referring to FIG. 17, in accordance with a second preferred embodiment, the photoresist 20i is used to fill the first relief structure 11i such that the surface of the photoresist 20i is flush with the upper surface of the substrate 10i. Is applied onto the substrate 10i. Referring to FIG. 18, the photoresist 20i is then exposed using a photo mask 30i overlying the substrate 10i, as shown in FIG. 19, and then firstly from the photoresist 20i. To allow access to a portion of the relief structure 11i and to leave residual exposed portions 22i of the photoresist 20i on the substrate 10i. The electrically conductive metal layer is shaped on the shaped surface, and the stamper 70 is then formed by electroforming, as shown in FIG. 20. The stamper 70 has a microstructure with excellent shape accuracy and good surface flatness since it is transformed from the first relief structure 11i first formed on the substrate 10i. Thereafter, a light transmitting plate such as a backlighting plate, a light guide plate or a front light plate having a microstructure with good shape accuracy and good surface flatness is produced by an injection mold using a stamper 70.

In a third preferred embodiment, the first relief structure 11j protrudes in a triangular cross section, as shown in Fig. 21A. Photoresist 20j is applied on substrate 10j such that the first relief structure 11j is included therein. The photoresist 20j is then exposed using a photo mask 30j overlying the substrate 10j, as shown in FIG. 21 (C), and then firstly from the photoresist 20j. To allow access to a portion of the relief structure 11j and to remove the exposed portion of the photoresist 20j to leave a residual exposed portion 22j of the photoresist on the substrate 10j, Thereby forming a surface shaped as a microstructure relief joined by the exposed portions of the first relief structure 11j and by the remaining unexposed portions 22j of the photoresist on the substrate 10j. Then, as in the method of the previous embodiment, a metal layer 40j is formed on the shaped surface, and then the metal product 50 'is subjected to electroforming, as shown in FIG. 21 (E). Is formed on the metal layer 40j. The metal product 50 'is continuously peeled off as shown in Fig. 21F. The metal product 50 ′ has a microstructure 51 ′ with a profile that is the opposite of the microstructure relief on the surface shaped in FIG. 21D.

Thus it has been shown that the method according to the invention applies the production of articles having good shape accuracy and good surface flatness and having microstructures which can be complicated in shape. The product may be used directly, or may be used to manufacture another product again.

While the invention has been described in terms of the most practical and preferred embodiments thereof, it is intended that the invention not be limited to the embodiments shown but within the scope and scope of the broad description to cover all such modifications and equivalent arrangements. It is to be understood that the device is intended to include various devices.

As described above, the present invention provides a method for producing a product having a relatively complex microstructure pattern and a microstructure having excellent surface flatness and a high level of shape accuracy, and a product produced by the method.

Claims (24)

a) forming a first relief structure on the surface of the substrate, b) applying photoresist on the substrate, c) exposing a portion of the photoresist using a photomask to form a microstructured pattern, and d) allowing access to a portion of the first relief structure from the photoresist by generating a microstructured pattern in the exposed photoresist, and thereby thereby exposing the photoresist on the substrate and by the exposed portion of the first relief structure. Forming a shaped surface with microstructure relief joined by the remainder. The method of claim 1, And said substrate is made of a material selected from the group consisting of metals, glass, ceramics and plastics. The method of claim 1, Wherein said first relief structure comprises a first parallel set of linear structures. The method of claim 3, wherein Further wherein the first relief structure comprises a second parallel set of linear structures that intersect with the first set of linear structures. The method of claim 1, Wherein said first relief structure comprises a set of concentric circles. The method of claim 1, Wherein said first relief structure comprises a set of curved structures. The method of claim 1, Wherein said first relief structure comprises at least one of a set of linear structures and a set of curved structures. The method of claim 1, In step (a), the first relief structure is formed by diamond cutting method for producing a product having a microstructure. The method of claim 1, Wherein said first relief structure is concave relative to the surface of said substrate. The method of claim 9, In step (b), the photoresist is applied to a substrate to fill the first relief structure. The method of claim 10, In step (b), the photoresist is applied on the substrate such that the surface of the photoresist is flush with the surface of the substrate. The method of claim 1, Wherein said first relief structure protrudes from the surface of said substrate. The method of claim 1, Add to, e) producing a microstructured product, comprising forming a metal layer on the shaped surface to form a microstructured product in a profile corresponding to the microstructure relief on the shaped surface. How to. The method of claim 13, Add to, f) forming a metal product on the metal layer such that the metal product has a microstructure in a profile opposite the microstructure on the product. The method of claim 14, and in step (f), said metal product is formed by electroforming. The method of claim 14, and in step (f), said metal product is formed by non-electroplating. The method of claim 14, Wherein said metal product is a stamper or mold used for manufacturing the product through metal casting. The method of claim 14, Wherein said metal product is a stamper or mold used for product manufacture through plastic casting. An optical reflecting plate made according to the method formed in claim 14. An optical diffusion plate made according to the method formed in claim 14. Stamper prepared according to the method formed in claim 14. A light transmitting plate made by using a stamper made according to the method formed in claim 18. A backlighting plate made by using a stamper made according to the method formed in claim 18. An all-illumination plate made by using a stamper made according to the method formed in claim 18.