KR20050005310A - Microlens array for projection display screen and the fabricating method thereof - Google Patents

Abstract

PURPOSE: A microlens array for a projection screen and a fabricating method thereof are provided to form the image having view angles in vertical and horizontal directions and simultaneously having high luminance on the projection screen and to obtain the image with high resolution through the formation of micropitch. CONSTITUTION: Plural microlenses(111) are arrayed and formed on the entire surface of a substrate(112) by a manufacturing process including a semiconductor fabricating process. A light diffusion layer is formed on the rear surface of the substrate. A protective layer is formed on the rear surface of the light diffusion layer. The microlens is formed as a planar-convex shape or a honeycomb shape. The interval of microlenses arrayed on the substrate is within several micrometers.

Description

Microlens array of projection screen and its manufacturing method {MICROLENS ARRAY FOR PROJECTION DISPLAY SCREEN AND THE FABRICATING METHOD THEREOF}

The present invention relates to a microlens array of a projection screen and a method of manufacturing the same. More specifically, it is possible to finely pitch in a projection system, to simultaneously secure vertical and horizontal viewing angles, and to obtain high brightness and high resolution images. A microlens array in a projection screen for imaging an enlarged projected image which can be made, and a method of manufacturing the same.

Recently, a projection television system has been developed to enlarge and view an image formed on a small screen according to a demand of a consumer who desires a large screen. Projection system technology refers to a technology that allows a user to see a large screen by enlarging and projecting a small image formed on a cathode ray tube (CRT) or a liquid crystal display (LCD) onto an projection screen.

1 to 3 show a conventional projection screen and a microlens arrangement used therein, FIG. 1 is a schematic view showing the structure of a conventional projection screen, and FIG. 2 shows the structure of the lenticular microlens of FIG. 3 is a sectional view taken along the line III-III of FIG.

As shown in the figure, a conventional projection screen is composed of a microlens array 10 and a Fresnel lens plate 20. The microlens array 10 includes a substrate 12 formed to couple and support the microlens 11, and a plurality of lenticular lenses, which are cylindrical lenses arranged and coupled to an upper surface of the substrate 12. 11), a light blocking film (Black matrix) 13 forming a light exit port, a light diffusion layer (Scatter) 14 formed of light diffusing fine particles to widen the viewing angle, and a transparent layer to protect the light diffusion layer 14. The resin film is configured to include a protective film 15 formed on the upper surface of the light diffusion layer 14.

In addition, the Fresnel lens plate 20 serves as a Fresnel lens substrate 21 supporting the Fresnel lens and a collimating lens in which symmetry is formed around the center of the screen so that light travels in parallel light. It consists of a Fresnel lens 22 to make.

The lens used in the conventional projection screen uses an array of lenticular microlenses 11 to widen the viewing angle in the horizontal direction. In the case of a projection screen requiring a high resolution such as a high definition television (HDTV), the lens is used to increase the resolution. The pitch of the Ticule microlens 11 should be made extremely small. In particular, in the case of a projection screen using a liquid crystal display (LCD), since each pixel of the liquid crystal panel is combined with the lenticular lens 11 to generate a moire pattern, the lenticular microlens 11 is prevented. Pitch may require fineness with a size of several hundred micrometers or less.

In general, the lenticular lens 11 is manufactured by molding a mold using a resin of plastic material by heat and / or pressure by making a mold, or in the form of an injection. This method produces a fine pitch due to uneven heat distribution over a large area. Since there is a limit in obtaining, the attempt to obtain a fine pitch by making it with the ultraviolet curable resin etc. which harden | cure using an ultraviolet-ray is in progress.

However, the lenticular microlens 11 used in a conventional projection screen has a cylindrical shape extending in the vertical direction and has a curved surface formed only in the horizontal direction so that incident light is refracted only in the left and right directions. Therefore, the prior art can secure a fine pitch, but the securing of the viewing angle in the vertical direction is inevitably dependent on the light diffusing layer 14, which makes it difficult to secure the viewing angle in the vertical direction and has low light efficiency due to the use of the light diffusing layer. There is a problem.

The present invention has been made to solve the problems of the prior art as described above, the image formed on the projection screen to ensure the viewing angle in the horizontal direction and the viewing angle in the vertical direction, at the same time have a high luminance and high resolution image through fine pitch It is an object of the present invention to provide a microlens array structure of a projection screen and a method of manufacturing the same.

1 to 3 show a conventional projection screen and a microlens array used therein,

1 is a schematic diagram showing the structure of a conventional projection screen

FIG. 2 is a front view showing the structure of the lenticular microlens of FIG.

3 is a cross-sectional view taken along line III-III of FIG.

4 and 5 are views showing a substrate and a microlens of the microlens array of the projection screen according to the first embodiment of the present invention;

4 is a front view showing the configuration of a microlens substrate and a microlens array substrate of a honeycomb array type of a projection screen according to a first embodiment of the present invention;

FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4. FIG.

Fig. 6 is a front view showing a substrate of an microlens array and an elliptical shape microlens of a projection screen according to a second embodiment of the present invention;

Fig. 7 is a front view showing a substrate of a microlens array and a rectangular microlens of a projection screen according to a third embodiment of the present invention;

Fig. 8 is a front view showing a substrate of a microlens array of a projection screen and a rounded rectangular microlens according to a fourth embodiment of the present invention.

Fig. 9 is a front view showing the substrate of the microlens array of the projection screen and the rounded rectangular microlens according to the fifth embodiment of the present invention.

Fig. 10 is a comparison graph in terms of viewing angle and light brightness between a conventional lenticular microlens array and a honeycomb microlens array according to a first embodiment of the present invention.

11 and 12 are schematic diagrams showing step by step a manufacturing process for manufacturing the honeycomb microlens array of FIG.

** Description of symbols for the main parts of the drawing **

111,126,211,311,411,511: microlenses

112: lens substrate 121: substrate

125: mold 127: light shielding film

128: light diffusion layer

The present invention, in order to achieve the above object, a substrate formed to mount a microlens; A plurality of microlenses formed in a honeycomb arrangement arranged on the front surface of the substrate; A light diffusion layer formed on a rear surface of the substrate; A protective layer formed on a rear surface of the light diffusion layer; It provides a microlens array of the projection screen, characterized in that configured to include.

As a result, compared to the conventional lenticular lens, while maintaining the same horizontal light efficiency and at the same time secure the vertical viewing angle, it is possible to use as a projection screen with improved brightness.

Here, the microlens is preferably formed of a Planar-Convex lens.

In addition, the shape of the microlens is effective to have the shape of a hexagon, a rectangle, and a rounded rectangle, including honeycomb, oval, and rectangular, in order to change the light emission angle according to the direction.

In addition, the spacing between the microlenses arranged on the substrate is effectively formed within a few micro.

Meanwhile, the arrangement between the microlenses formed on the substrate may be configured to overlap the edges of the microlenses.

At this time, the microlens is preferably formed such that the cut surface of the boundary surface configured such that the edges overlap each other has an arbitrary curvature.

In addition, it is effective that the microlenses have different curvatures of up, down, left, and right of the lens for adjusting the light exit angle.

Herein, the curvature of the microlenses is preferably determined by the lengths of the top, bottom, left, and right sides of the microlens, the height of the lens, and the respective aspherical surface constant values.

In addition, the light emission angle of the microlens is preferably formed at a horizontal axis with respect to the normal of the lens plane at a left and right exit angle of 30 degrees or more, and a vertical axis having a vertical exit angle of 15 degrees or more.

In addition, it is effective that the substrate is formed of a multi-material material that serves as a support for forming a lens.

In addition, it is preferable that an aligned light output aperture corresponding to each of the microlenses is formed on the rear surface of the substrate.

In addition, it is effective that a black light blocking film is formed on the rear surface of the substrate except for the light exit port.

On the other hand, according to another aspect of the present invention, a method of manufacturing the microlens array, comprising the steps of: manufacturing a mold master by forming a plurality of microlenses on the substrate; Forming a mold using the arrayed microlenses as a mold master; Forming a plurality of arranged microlenses using the mold; Forming a light blocking film; Forming a light diffusion layer; Forming a protective layer; It provides a method of manufacturing a microlens array of the projection screen, characterized in that it comprises a.

This is to reduce the error range according to the working process, to improve productivity and to reduce the manufacturing cost by using a semiconductor manufacturing technology including a photo drawing process in the manufacturing process of the microlens array.

Here, in the forming of the microlenses using the mold, it is preferable to form the microlenses arranged by a curing method through compression molding and ultraviolet irradiation using a transparent lens forming material.

On the other hand, the step of forming the microlens using a mold may form a microlens arranged by a high temperature high pressure molding method or an injection molding method.

In addition, the forming of the mold is performed by plating the surface of the mold master in the form of a microlens formed through a photo drawing process for forming a fine pattern using a photosensitive agent and a reflow process for making a lens shape. It is preferable to form

In addition, the photosensitive agent is preferably a film (Polymer) in the form of a film capable of coating, adhesion of several tens of micrometers.

In the forming of the light blocking film, the light blocking film is laminated by using an adhesive layer film having a photosensitive property on a rear surface of a microlens array; Irradiating the microlens array with ultraviolet rays, photocuring only a portion where light is collected on the film, thereby losing adhesiveness; Coating a black coating agent to produce a light blocking film that prevents light inflow in an area except for light exit holes aligned with the microlens array; It is effective to form.

In addition, the photosensitizer is effective in the form of a film (Polymer) capable of coating, adhesion of several tens of micrometers.

The mold master fabrication process is performed by depositing a predetermined thickness on the entire surface of the lens by using a material that can be deposited with a uniform thickness while maintaining the shape on the master shape surface after the reflow process to increase the filling rate. It is preferable to include a process of manufacturing the overlapping edges of the lens while filling the fine gap.

In this case, it is effective that the light exit port corresponding to each microlens of the light shielding film is formed by irradiating ultraviolet rays to remove only the photosensitive material in the portion where the light is collected.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, in describing the present invention, a detailed description of known functions or configurations will be omitted to clarify the gist of the present invention. Incidentally, the same or equivalent components as those described above are given the same or equivalent reference numerals, and detailed description thereof will be omitted.

4 and 5 are views showing a substrate and a microlens of the microlens array of the projection screen according to the first embodiment of the present invention, Figure 4 is a honeycomb array form of the projection screen according to the first embodiment of the present invention ( Honeycomb array type) of the microlens array substrate and the front view showing the configuration of the microlens, Figure 5 is a cross-sectional view taken along the cutting line V-V of FIG.

In the projection screen, the conventional lenticular lens array is curved in the horizontal direction only in the form of a cylinder, and is refracted only in the horizontal direction, so that the viewing angle in the vertical direction is difficult to be secured to a certain level or more, as shown in FIGS. 4 and 5. As described above, the microlens array of the projection screen according to the embodiment of the present invention is formed in the form of a honeycomb 111 to have a curved surface in both the horizontal direction and the vertical direction to secure a considerable level of viewing angle, which is a microlens. And a plurality of microlenses 111 formed in a honeycomb form densely arranged on the upper surface of the substrate 112.

Here, the microlens 111 is a planar-convex lens formed by two-dimensionally arranged unit microlenses having an elliptical, hexagonal, or quadrangular shape. The microlens 111 may be configured as a spherical or aspherical microlens. In addition, the substrate 112 is formed of a transparent polymer that serves as a pedestal required for molding the microlens.

On the other hand, the light exit holes arranged in correspondence with each individual lens are formed on the rear surface of the transparent substrate 112 of the molded microlens array, and the front surface except the light exit holes is formed with a black mask. It consists of.

On the other hand, even in the case of a honeycomb-type microlens array structure, an appropriate lens shape design is required in order to maintain a constant luminance while maintaining the overall light output and securing a vertical viewing angle. That is, the shape of the individual lens is preferably formed in a honeycomb arrangement close to the ellipse or hexagon shape long in the vertical direction, as shown in FIG.

On the other hand, by configuring as described above, it is possible to ensure the viewing angle in the vertical direction due to the application of the microlens 111 formed in the honeycomb shape, the light diffusion layer that reduces the amount of light efficiency is reduced, accordingly Even for the same light output, the viewing angle in the vertical direction is improved, thereby increasing the overall light efficiency.

Fig. 6 is a front view showing the substrate of the microlens array of the projection screen and the elliptical microlens according to the second embodiment of the present invention, and Fig. 7 is the microlens array of the projection screen according to the third embodiment of the present invention. Fig. 8 is a front view showing a substrate and a rectangular microlens in a rectangular shape, and Fig. 8 is a front view showing a substrate and a rounded rectangular microlens in a microlens array of a projection screen according to a fourth embodiment of the present invention. 9 is a front view showing an elliptical microlens arranged diagonally with a substrate of a microlens array of a projection screen according to a fifth embodiment of the present invention.

As shown in the figure, the shape of the microlenses in the microlens array may be an elliptical microlens 211 as shown in FIG. 6, and a rectangular microlens 311 as shown in FIG. 8 may be a rectangular microlens 411 having rounded corners as shown in FIG. 8, or may be an elliptical microlens arranged diagonally as shown in FIG. 9.

In the drawings, reference numeral 212 denotes a substrate for mounting and supporting the elliptical microlens 211, 312 denotes a substrate for mounting and supporting the rectangular microlens 311, and 412 denotes a rectangular microlens with rounded corners. 411 is a substrate for mounting and supporting, and 512 is a substrate for mounting and supporting the elliptical microlens 511.

By applying the microlenses of various shapes to the projection screen as described above, as in the case of the honeycomb microlens as in the first embodiment, the horizontal viewing angle and the excellent vertical viewing angle are obtained. You can get it.

FIG. 10 is a comparison graph in terms of viewing angle and light luminance between a conventional lenticular microlens array and a honeycomb microlens array according to a first embodiment of the present invention, and FIG. Fig. 10B shows luminance in the vertical direction according to the viewing angle.

Here, the solid line represents the luminance with respect to the viewing angle of the honeycomb microlens 111, and the dotted line represents the luminance according to the viewing angle of the conventional lenticular microlens 11.

As shown in the graph, when the honeycomb-type microlens 111 is used, the vertical viewing angle is even higher while maintaining a superior horizontal viewing angle than when a conventional lenticular microlens is used. Viewing angle can be secured. There is a limit to increase the existing light efficiency, and the horizontal viewing angle is more important than the vertical viewing angle when the viewer watches the projection television, so it must be designed to have a large value. To make the optimum condition. In addition, the honeycomb lens 111 has the advantage of being able to apply a fine photographic drawing process and a reflow technique, which is a semiconductor process, in addition to securing a viewing angle, thereby enabling fine pitch fabrication to increase resolution.

In addition, the bottom surface of the honeycomb microlens has a structure that can be filled with the smallest gaps to minimize the gap between the lens and the lens to maximize the fill factor.

The honeycomb microlens array as described above may be manufactured by forming a mold through a reflow technique and a plating process, and then continuously forming and replicating a transparent resin suitable for the lens using the mold.

Here, the fabrication of the mold master of the honeycomb microlens for the mold fabrication is implemented by a photolithography process and a reflow technique, which are semiconductor processes. That is, after forming the bottom shape of elliptical, hexagonal or square in a honeycomb array using a photo drawing process, the optically transparent polymer material is more than the glass transition temperature by using the reflow technology by heat treatment. The partial spherical lens having an arbitrary curvature is made by the surface tension induced by heating.

At this time, by adjusting the bottom shape and the thickness of the polymer, and by adjusting the temperature and time when using the reflow technology it is possible to manufacture a microlens of the desired shape. Since the photographic drawing process and the reflow technique as described above have an advantage of excellent reproducibility and easy adjustment of the shape, the shape of the mold master of the microlens array can be manufactured.

11 and 12 are schematic diagrams showing step by step a manufacturing process for manufacturing the honeycomb microlens array of FIG. 4, and as shown in the drawing, the honeycomb microlens array is manufactured by the following process. .

As shown in Fig. 11 (a), the shape of the microlenses is determined based on the optical design for fabrication of a mold having the shape of the microlenses. And based on this, the photomask is transferred to the board | substrate 121 using the photographic drawing process which is a semiconductor integrated process. At this time, it is preferable that the photosensitive agent 122 used can implement a film having a thickness of several tens of micrometers.

Then, as shown in Fig. 11B, by using a reflow technique, temperature and time are adjusted to obtain a spherical microlens 123 that becomes a mold master shape of the spherical lens. At this time, in order to form a small gap between the microlens 123 and the microlens 123, the surface state may be changed through an etching technique or the like.

At this time, in order to increase the fill factor (fill factor) in order to fill or minimize the gap between the micro-lens using a material that can be deposited with a uniform thickness while maintaining the shape on the lens-shaped surface of the mold master as it is By depositing a predetermined thickness on the entire surface, a process method including a process of filling the edges of the lens and overlapping the edges of the lens may be added.

Then, as shown in FIG. 11 (c), a metal thin film 124 such as chromium (Cr) or gold (Au) is seeded to plate the upper surface of the manufactured microlens 123. By the sputtering method utilized in the semiconductor manufacturing process.

Next, as shown in FIG. 11 (d), nickel (Ni) or the like is formed by electroplating or electrolessplating on a plating frame formed of an array of microlenses 123 and a seed layer. The mold 125 is made of a metal suitable for the mold use of the mold. At this time, it is preferable to add a chemical treatment or a mechanical polishing process in order to adjust the smoothness of the entire surface.

Next, as shown in FIG. 11 (e), a precision mold for molding a microlens array processed through the above process is used to form a top surface of a transparent support such as a PET (Poly Ethylene Terephthalate) substrate. After applying a resin layer such as polycarbonate or PMMA suitable for molding process, it is pressed into a mold and compressed into a mold, and a microlens array in the form of a honeycomb array is formed by an ultraviolet curing method, a heat compression molding method or an injection molding method. 126) can be duplicated.

As a post-process, as shown in Fig. 12 (a), after the lamination is performed using an adhesive layer film having a photosensitive characteristic on the opposite side where the microlens array is located, the film is irradiated with ultraviolet rays with a lens array to light the film. Only this light-condensed portion is photocured to lose adhesiveness. The black coating agent is coated to generate a light blocking film 127 that prevents light inflow in an area except for the light exit holes arranged in the microlens array. At this time, after coating or laminating a black film or liquid photosensitive material to be used as the light blocking film, the light emitting spheres are formed on the light blocking film 127 so as to correspond to each microlens by irradiating the photosensitive material with ultraviolet rays. .

Then, as shown in Fig. 12B, a coating liquid containing fine particles to be used as the light diffusing layer 128 is applied to the microlens array 126, or a thin plate-shaped light diffusing layer is adhered using an adhesive. .

Finally, as shown in Fig. 12 (c), the manufacturing of the microlens array screen having a honeycomb form is completed by adhering the transparent resin plate 129 serving as an antistatic function, an antireflection function, and a protective film.

While the exemplary embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited only to the specific embodiments, and may be appropriately changed within the scope described in the claims.

As described above, the present invention provides a honeycomb-type microlens array in the screen of the projection system, while maintaining the same optical efficiency as compared to the conventional lenticular lens while at the same time securing a vertical viewing angle and improving the brightness of the projection screen It provides a microlens array of and a method of manufacturing the same. In addition, the manufacturing method can reduce the error range according to the work process, improve the productivity and reduce the manufacturing cost by using a semiconductor manufacturing technology, such as a photo drawing process, a reflow process, a plating process for the mold.

Claims (24)

A substrate formed to mount a microlens; A plurality of formed microlenses arranged and mounted on a front surface of the substrate by a manufacturing method including a semiconductor processing technique; A light diffusion layer formed on a rear surface of the substrate; A protective layer formed on a rear surface of the light diffusion layer; Microlens array of the projection screen, characterized in that it comprises a. The method of claim 1, And said microlenses are formed as planar-convex lenses. The method of claim 1, The microlens array of the projection screen, characterized in that the microlens is formed in a honeycomb form. The method of claim 1, The microlens array of the projection screen, characterized in that formed in the oval shape. The method of claim 1, The microlens array of the projection screen, characterized in that formed in a rectangular shape. The method of claim 1, The microlens array of the projection screen, characterized in that formed in a rectangular shape with rounded corners. The method of claim 1, Wherein the spacing between the microlenses arranged on the substrate is within a few microns. The method of claim 1, The microlens array of the projection screen, characterized in that the array between the microlenses formed on the substrate to improve the area ratio occupied by the microlens to the entire area of the substrate by configuring the edges of the microlens overlap each other. The method of claim 8, And the microlenses are formed such that the cut surface of the boundary surface configured such that the edges overlap each other has an arbitrary curvature. The method of claim 1, The microlens is a microlens array of the projection screen, characterized in that the upper and lower left and right curvature of the lens is formed to adjust the light exit angle. The method of claim 10, And the curvature of the microlenses is determined by each of the lengths of the top, bottom, left, and right sides of the microlens, the height of the lens, and the respective aspherical surface constant values. The method of claim 1, And the light exit angle of the microlens is in a horizontal axis with respect to the normal of the lens plane, and the left and right exit angles are 30 degrees or more. The method of claim 1, And a range of light exit angles of the microlenses in a vertical axis with respect to a normal line of the lens plane. The method of claim 1, The substrate is a microlens array of the projection screen, characterized in that formed of a multi-material material that serves as a support for forming the lens. The method of claim 1, And an aligned light exit aperture corresponding to each of the microlenses is formed on a rear surface of the substrate. The method of claim 11, And a black light blocking film formed on a rear surface of the substrate except for the light exit port. A method of manufacturing the microlens array of claim 1, Manufacturing a mold master by forming a plurality of microlenses on the substrate; Forming a mold using the arrayed microlenses as a mold master; Forming a plurality of arranged microlenses using the mold; Forming a light blocking film; Forming a light diffusion layer; Forming a protective layer; Method for producing a microlens array of the projection screen, characterized in that it comprises a. The method of claim 17, The forming of the microlenses using the metal mold comprises: forming microlenses arranged by a curing method through compression molding and ultraviolet irradiation using a transparent lens forming material. The method of claim 17, Forming a microlens using a mold is a method of manufacturing a microlens array of a projection screen, characterized in that to form a microlens arranged by a high temperature high pressure molding method. The method of claim 17, The step of forming the microlenses using a mold comprises the steps of forming a microlens arranged by an injection molding method. The method of claim 17, The forming of the mold may include forming a mold on the surface of a mold master having a microlens array type by using a photoresist and a reflow process using heat treatment. Method of making a microlens array. The method of claim 21, The photosensitive agent is a method of manufacturing a microlens array of the projection screen, characterized in that the coating of several tens of micrometers (Polymer) in the form of a film capable of adhesion. The method of claim 17, In the forming of the light blocking film, the light blocking film is Lamination using an adhesive layer film having photosensitive characteristics on the rear surface of the microlens array; Irradiating the microlens array with ultraviolet rays, photocuring only a portion where light is collected on the film, thereby losing adhesiveness; Coating a black coating agent to produce a light blocking film that prevents light inflow in an area except for light exit holes aligned with the microlens array; Method for producing a microlens array of the projection screen, characterized in that it is formed. The method of claim 23, wherein The light output port corresponding to each microlens of the light shielding film is further formed by irradiating ultraviolet light to remove only the photosensitive material of the portion where the light is collected. Way.