Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0033—Means for improving the coupling-out of light from the light guide
  • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
  • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F13/00—Bandages or dressings; Absorbent pads
  • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
  • A61F13/45—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the shape
  • A61F13/49—Absorbent articles specially adapted to be worn around the waist, e.g. diapers
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0065—Manufacturing aspects; Material aspects
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F13/00—Bandages or dressings; Absorbent pads
  • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
  • A61F13/45—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the shape
  • A61F13/49—Absorbent articles specially adapted to be worn around the waist, e.g. diapers
  • A61F2013/49096—Absorbent articles specially adapted to be worn around the waist, e.g. diapers with braces
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F13/00—Bandages or dressings; Absorbent pads
  • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
  • A61F13/45—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the shape
  • A61F13/49—Absorbent articles specially adapted to be worn around the waist, e.g. diapers
  • A61F2013/49098—Other Details not otherwise provided of the absorbent articles specially adapted to be worn around the waist

Definitions

• the present invention relates to nano-patterning and micro-molding technologies, and more particularly, to a method of manufacturing a non-symmetric multi-curvature microlens for controlling light diffusion and a viewing angle in a microlens array, a light guide plate or the like, and a light guide plate manufactured by the method.
• Background Art
• LCDs liquid crystal displays
• a backlight unit is used as an illumination device that provides light uniformly over an entire panel of the LCD.
• the backlight unit comprises a background light source, a reflection plate for reflecting light, a light guide plate, a diffusion plate and the like.
• the light guide plate functions to uniformly radiate light, which is emitted from the background light sources used as light sources at both lateral sides of the light guide plate, onto an entire surface of the liquid crystal display.
• the light guide plate is configured in the following manner. That is, a plurality of prisms are arranged in one direction over an entire surface of the light guide plate such that V-shaped grooves are formed between the adjacent prisms, or diffusive ink dots with a certain size are arranged on the entire surface of the light guide plate.
• the V-shaped groove pattern should be mechanically processed to form the prisms on the entire surface of the light guide plate.
• the liquid crystal display optically requires light with a large emergence angle such as about 90 degrees with respect to the surface of the display.
• the emergence angle of light emitted from the conventional light guide plate is very small on the order of about 30 degrees with respect to the surface of the light guide plate.
• an expensive prism film or diffusion film should be used to increase the emergence angle.
• An object of the present invention is to provide a method of manufacturing a non-symmetric multi-curvature microlens on a light guide plate wherein each microlens has non- symmetric different curvature in at least one direction, and a light guide plate manufactured by the method.
• Another object of the present invention is to provide a method of manufacturing a non-symmetric multi-curvature microlens on a light guide plate wherein the size or arrangement of the non-symmetric multi-curvature microlens on the light guide plate can be easily adjusted according to the intention of a user, and a light guide plate manufactured by the method.
• a method of manufacturing a non-symmetric multi-curvature microlens on a light guide plate comprising a first step of aligning a mask on a substrate coated with a photoresist, the mask being composed of a first region through which light can be transmitted and a plurality of second regions through which light cannot be transmitted; a second step of performing inclined light exposure at least once such that light is radiated from an upper side to a lower side of the second region at a non- symmetric inclination angle in at least one direction; a third step of developing the substrate subjected to the inclination light exposure and obtaining a plurality of photoresists in the form of non-symmetric truncated cone; a fourth step of performing a reflow process to allow the non-symmetric truncated cone shaped photoresists to be curved such that non-symmetric multi-curvature microlens shaped photoresists are obtained;
• a non-symmetric multi-curvature microlens can be manufactured by means of photoresists formed by inclined light exposure through a reflow process, a fine non-symmetric multi-curvature microlens array pattern can be easily obtained through a simple manufacturing process. Therefore, there is an advantage in that the production costs and time can be reduced.
• a non-symmetric multi-curvature microlens of the present invention has an improved function of controlling refraction and diffused reflection of light, a desired optical performance can be obtained.
• the non-symmetric multi-curvature microlens can be easily applied to a light guide plate or the like by using the non- symmetric multi-curvature microlens array pattern.
• FIG. 1 is a perspective view of a mask for use in the present invention.
• Figs. 2 to 4 show light exposure processes of fabricating photoresists taking the shape of a non-symmetric truncated elliptical cone according to an embodiment of the present invention.
• FIGs. 5 and 6 are sectional views showing the sizes and shapes of the photoresists taking the shape of a non-symmetric truncated elliptical cone fabricated according to the embodiment of the present invention.
• Figs. 7 to 9 show the shapes of the photoresists which were changed into the non- symmetric multi-curvature microlenses after a reflow process according to the embodiment of the present invention.
• FIGs. 10 and 11 show a process of fabricating an engraved stamper according to the embodiment of the present invention.
• Fig. 12 is a schematic view showing a process of fabricating an embossed stamper according to the embodiment of the present invention.
• a mask 21 for use in a light exposure process is first fabricated, as shown in Fig. 1.
• a film mask or chromium mask may be used as the mask 21 depending on pattern precision.
• the mask can be fabricated with a precision of about 1 D.
• Fig. 1 is a perspective view of a mask for use in the present invention. As shown in this figure, the mask 21 is composed of a first region 22 through which light can be transmitted, and a plurality of second regions 23 through which light cannot be transmitted.
• each of the second regions 23 is preferably formed in an elliptical shape but may be formed in other shapes such as a circle, rectangle, pentagon, hexagon or the like.
• the mask 21 of the present invention may be formed such that the plurality of second regions 23 may have the same shape and spacing. However, the plurality of second regions 23 may have the same elliptical shape but different sizes and spacing, as shown in Fig. 1.
• the elliptic sizes of the respective second regions 23 may be different from one another, the spacing between the second regions 23 may be set different form one another, and the second regions 23 may be arranged in any direction.
• the second regions 23 may be arranged in various forms over the entire region of the mask 21, and the unspecific arrangement of the second regions is also intended to obtain optimum optical performance over an entire region of a liquid crystal display (LCD).
• Figs. 2 to 4 show light exposure processes of fabricating photoresists taking the shapes of non-symmetric truncated elliptical cones according to an embodiment of the present invention.
• a photoresist (PR) 32 is first coated on a glass or silicone wafer substrate 31 using a spin coater (not shown). At this time, the kind of the photoresist 32 to be used can vary according to the thickness thereof.
• the coated substrate 31 is subjected to soft baking in an oven. At this time, the coated substrate is preferably baked at as temperature of 70 to 120°C for about 2 to 30 minutes.
• the mask 21 is aligned on the PR-coated substrate 31 as shown in Fig. 3. At this time, the mask 21 is aligned by the guidance of an align key (not shown).
• a light exposure process is performed by radiating light from an upper side of the mask 21.
• inclined light exposure is also performed such that light radiated to a lower side of the second region 23 in the mask 21 can be radiated at an inclination angle in at least one direction.
• inclined light exposure may be performed at least once at different radiation angle.
• light is preferably radiated to form an opposite angle from each of longitudinal ends of the second region 23.
• Ra and Ra designate the widths (length of minor axis) of the second regions 23 in a horizontal direction
• Rb and Rb designate the widths (length of minor axis) of the second regions 23 in a vertical direction.
• La and La designate the spacing between the adjacent second regions 23 in a horizontal direction
• Lb and Lb designate the spacing between the adjacent second regions 23 in a vertical direction.
• a developing process is performed in such a manner that the substrate is dipped in a developing solution at room temperature.
• the photoresist 34 has been formed into a truncated elliptical cone of which a top surface has the same shape as the second region 23 but an inclined surface becomes wider toward the bottom as a result of the inclined light exposure.
• the PR 34 may be shaped as a non-symmetric truncated elliptical cone depending on the radiation angle and direction of the inclined light exposure.
• the non-symmetric truncated elliptical cone shapes of the plurality of photoresists 34 manufactured through the light exposure process depend on the arrangement and shape of the second regions 23 in the mask 21.
• the non-symmetric truncated elliptical cone shaped PRs 34 may be different from one another in view of their sizes, spacing and heights.
• Fig. 5 is a sectional view of the non-symmetric truncated elliptical cone shaped photoresists 34 on the light-exposed substrate taken along a direction corresponding to a major axis thereof
• Fig. 6 is a sectional view of the non-symmetric truncated elliptical cone shaped photoresists 34 on the light-exposed substrate taken along a direction corresponding to a minor axis thereof.
• the non-symmetric truncated elliptical cone shaped photoresists 34 are fabricated to have the same height but different sizes and horizontal/vertical spacing La and Lb.
• a reflow process is performed using a hot plate apparatus to allow the non-symmetric truncated elliptical cone shaped photoresists 34 to be curved or bent.
• the photoresists (PRs) 34 are heated so that the photoresists (PRs) can be melted down.
• the conditions of the reflow process may vary according to the shape of the PR to be manufactured.
• the reflow process is executed at a temperature of 100 to 200°C for several minutes.
• Fig. 7 is a plan view showing a state where the PRs are arranged in a curved line after the reflow process according to the present invention
• Fig. 8 is a plan view showing a state where the PRs are arranged in a straight line after the reflow process according to the present invention
• Fig. 9 is a sectional view showing a state of the PRs after the reflow process according to the present invention.
• the non-symmetric truncated elliptical cone shaped photoresists 34 are manufactured into PRs 36 taking the shape of a non-symmetric multi- curvature microlens through the reflow process.
• the non-symmetric multi-curvature microlens shaped PR 46 is primarily determined by means of an inclined light exposure angle for determining the inclination of the non-symmetric truncated elliptical cone shaped PRs 34 shown in Figs. 4, 5 and 6 and then secondarily determined by means of factors (i.e., temperature and period of time) of the reflow process, so that the PRs 36 can be fabricated in various forms of non-symmetric multi-curvature microlenses.
• the desired non- symmetric multi-curvature microlens shaped PR 36 can be fabricated through the processes of controlling the shapes, sizes and arrangement of the second regions 23 in the mask 21, of controlling the angle and direction of inclination light exposure, and of controlling the temperature and period of time in the reflow process. Moreover, the desired optical system design can be easily obtained.
• Figs. 10 and 11 show a process of fabricating an engraved stamper according to the embodiment of the present invention.
• a metallic thin film 41 is coated on the substrate 31 on which the plurality of the non-symmetric multi-curvature microlens shaped PRs 36 are formed.
• the coating of the metallic thin film 41 typically contains chromium.
• the coating of the thin film may additionally contain gold.
• the substrate 31 is mounted to a plating apparatus and plated with nickel through an electroplating process, as shown in Fig. 11.
• an electric current supplied to the substrate is several amperes depending on each step of the electroplating process. Consequently, the plating thickness becomes 400 to 450 D (for a 4-inch wafer), and a nickel-plated portion becomes a stamper 42.
• the stamper 42 After the stamper 42 has been obtained through the nickel electroplating process, the stamper 42 is separated from the substrate 31.
• the separated stamper 42 has a configuration in which an array pattern of the non-symmetric multi-curvature mi- crolenses 36 is transferred thereon in an engraved fashion.
• the stamper 42 (hereinafter, referred to as an "engraved stamper") has an engraved array pattern in the form of the non-symmetric multi-curvature microlens 36, and the non-symmetric multi-curvature microlens 36 formed between spherical lens features is formed in an embossed fashion.
• the engraved stamper 42 can be used as a mold for forming a light guide plate or microlens array on which an array pattern of a non- symmetric multi-curvature microlens is formed in an embossed fashion.
• the engraved stamper 42 may be used to form another embossed stamper which in turn is used to fabricate a light guide plate formed with an engraved array pattern of the non-symmetric multi-curvature microlens.
• Fig. 12 is a schematic view showing a process of fabricating the embossed stamper according to the embodiment of the present invention. As shown in this figure, an additional nickel electroplating process is further performed on the array pattern of the non-symmetric multi-curvature microlens of the engraved stamper 42.
• the new nickel-plated portion 44 separated from the engraved stamper 42 becomes a new embossed stamper 44 on which the pattern of the engraved stamper 42 has been transferred.
• the new embossed stamper 44 is configured in such a manner that the array pattern of the non-symmetric multi-curvature microlens is formed in an embossed fashion but grooves are formed in an engraved fashion between the non-symmetric multi-curvature microlenses.
• the embossed stamper 44 can be used as a mold for forming a light guide plate (not shown) with an array pattern of an engraved non-symmetric multi- curvature microlens.
• the photoresists 32 are first formed into the non-symmetric truncated elliptical cone shaped photoresists 34 by performing the inclination light exposure twice, and the non-symmetric truncated elliptical cone shaped photoresists 34 can then be formed into a non-symmetric multi- curvature microlense shaped photoresists 36 through the heat treatment using the reflow characteristics of the photoresist.

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• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Heart & Thoracic Surgery (AREA)
• Epidemiology (AREA)
• Biomedical Technology (AREA)
• Manufacturing & Machinery (AREA)
• Vascular Medicine (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Optical Elements Other Than Lenses (AREA)
• Preparing Plates And Mask In Photomechanical Process (AREA)

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• 2005
  • 2005-04-15 KR KR1020050031596A patent/KR100698636B1/ko not_active IP Right Cessation
  • 2005-12-12 WO PCT/KR2005/004243 patent/WO2006109920A1/en active Application Filing

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