KR20090100821A - Lightguide film and light emitting keypad comprising the same - Google Patents

Abstract

PURPOSE: A light guide film and a light emitting keypad comprising the same are provided to remove a durability problem of the light guide film and slim the light guide film by using a slim reinforcing coating film. CONSTITUTION: A light guide film(10) for a light emitting keypad guides light incident from a light source and surface-emits the light. A reinforcing coating film(11) is formed on at least one of an upper surface and a lower surface of the light guide film for a light emitting keypad. A dot pattern(12) is formed on upper/lower parts of the light guide film in which a reinforcing coating film is formed. The dot pattern is to increase brightness in a part corresponding to a key area of the light emitting keypad.

Description

Light Guide Film and Light Emitting Keypad Comprising The Same

The present invention relates to a waveguide film and a light emitting keypad for a light emitting keypad.

The top-view LED type light emitting keypad used as a light source of the light emitting keypad has a relatively thick keypad due to the characteristics of the top view LED and uses a large number of LEDs. do.

In order to overcome such limitations of the conventional top view LED light emitting keypad, a slim type light emitting keypad to which an EL (Electro Luminescence) lamp light emitting method (hereinafter, referred to as an 'EL method') has been developed.

1 is a cross-sectional view of a conventional EL type light emitting keypad for supplementing the above problems, and includes a key top 210, an EL metal dome sheet 220, and a printed circuit board 230. The 220 is composed of an EL sheet 221, a metal dome 223, and a base tape 222 to realize ultra thin film and low power consumption.

Looking at the function of the EL-type metal dome keypad, when the key top 210 is pressed by the user, the fixed contact of the metal dome 223 and the printed circuit board 230 by the projection 211 located at the rear of the key top 210. Terminal 231 is contacted and switched on to operate.

Such an EL type light emitting keypad has the advantage of providing uniform surface light emission, but there is a problem of noise generation, which may cause a malfunction. In addition, the EL method is an AC device, and since circuit components such as an inverter and an inductor must be essentially configured, there is a problem that a mounting space problem and an additional cost problem occur.

In the light emitting device of the light emitting keypad, two essential elements for the success of the commercialization is the excellent light emission and the cost competitiveness. As described above, the EL type light emitting keypad can achieve excellent light emission and a uniform light emitting surface, but the cost competitiveness is greatly reduced, and the recent market tends to give priority to the price competitiveness.

Recently, in the light emitting keypad market, in order to secure cost competitiveness, the light emitting method has shown a tendency to return from the EL method to the conventional LED method. Furthermore, a light emitting film can be used to obtain an excellent light emitting surface even with a small number of LEDs. Side LED light emitting method that can be raised.

However, when the light guide film is used, a very thin film is used for slimming. Due to the characteristics of the keypad, a number of key manipulations occur and problems such as durability and reliability occur due to cracking of the light guide film due to such frequent shocks. have.

In addition, even though it is a side-emitting method to guide light through the light guide film to induce surface light emission, it is not easy to solve the problem that the brightness decreases away from the light source, and to form a pattern on the light guide film to compensate for this, Still showing limits. In particular, when the pattern is formed on the light guide film, the problem of cracking of the light guide film becomes more problematic.

The present invention is to comprehensively solve the above problems,

The light guide film and the light emitting keypad can be used to solve the durability problem of the light guide film by adopting a slim reinforcement coating film, and to improve the light guide efficiency by totally reflecting a part of the light through the reinforcement coating film having a smaller refractive index than the light guide film. It aims to provide.

The present invention for achieving the above object,

A waveguide film for a light emitting keypad for guiding surface light emitted from a light source, wherein a reinforcement coating film is formed on at least one surface of an upper surface and a lower surface of the waveguide film, and light emission is formed on the upper or lower portion of the waveguide film on which the reinforcement coating film is formed. Provided is a waveguide film for a light-emitting keypad in which a dot (DOT) pattern for increasing luminance is formed in a portion corresponding to a key region of a keypad.

In addition, the upper or lower portion of the waveguide film is provided with a waveguide film for a light-emitting keypad, characterized in that the reinforcing projections formed by printing the cured ink on the portion corresponding to the key region of the light-emitting keypad is cured.

In addition, the reinforcing projections provide a waveguide film for a light-emitting keypad, characterized in that formed integrally with the reinforcement coating film without an interface.

In addition, the height of the reinforcing protrusions provides a waveguide film for a light emitting keypad, characterized in that in the range of 50 ~ 250㎛.

In addition, the refractive index of the reinforcing coating film is characterized in that less than the refractive index of the waveguide film, preferably, the refractive index of the reinforcing coating film provides a waveguide film for a light-emitting keypad, characterized in that 0.4 ~ 0.9 times the refractive index of the waveguide film.

The present invention also provides a key plate formed with a plurality of keys; The aforementioned waveguide film formed under the keypad; A light source positioned at a side of the waveguide film to irradiate light to the waveguide film; And a printed circuit board positioned below the waveguide film and having a dome switch.

The waveguide film and the light emitting keypad including the same according to the present invention adopt a slim reinforcement coating film to solve the durability problem of the waveguide film while realizing slimming, and also total reflection efficiency during light guide through the reinforcement coating film having a smaller refractive index than the waveguide film. It is possible to increase the amount of light reaching a position far from the light source by increasing the number, thereby providing a waveguide film and a light emitting keypad that can obtain an even light emitting area.

Hereinafter, the present invention will be described in more detail with reference to the drawings and examples. The drawings are not shown in actual size and proportion, and should be considered to be somewhat exaggerated for convenience of description.

The waveguide film according to the present invention solves the durability problem of the light guide film by forming a slim reinforcement coating film on at least one surface of the light guide film, and also configures the reinforcement coating film to have a smaller refractive index than the light guide film to totally reflect a part of the light. It is characterized in that an even emission area can be obtained by increasing the efficiency.

FIG. 2 is a plan view of a waveguide film for a light emitting keypad according to an embodiment of the present invention, and FIGS. 3A to 3C are cross-sectional views of the waveguide film of FIG. 2 and show various embodiments.

That is, the waveguide film of the present invention is a waveguide film for a light-emitting keypad that guides the light incident from the light source to the surface light-emitting, the reinforcement coating film 11 is formed on at least one or more of the upper and lower surfaces of the waveguide film 10, A dot (DOT) pattern 12 is formed on a portion corresponding to a key region of the light emitting keypad to increase luminance at an upper portion or a lower portion of the waveguide film on which the reinforcement coating layer 11 is formed.

By forming the reinforcing coating film 11 on the waveguide film 10, the waveguide film is prevented from being damaged by frequent pressurization of the keypad, thereby significantly improving durability, thereby obtaining long-term light guide reliability.

Although the waveguide film 10 is not limited, polycarbonate, polyethylene terephthalate, acrylic film, etc. having excellent optical transparency may be used, and when considering slimming, light guide efficiency, and click feeling of the dome sheet, 50 to 250 A thickness of mu m is preferred. In particular, polycarbonate has a high refractive index of about 1.5 and is suitable for application to the present invention.

In addition, in order to further increase the refractive index of a waveguide film, you may manufacture by containing a high refractive index and a transparent filler. Examples thereof include ZnO (1.9), TiO ₂ (2.5), CeO ₂ (1.9), ITO (1.95), ZrO ₂ (2.1), and the like, and the content ranges from 1 to 30% by weight based on the waveguide film. Can be used as

A reinforcement coating layer 11 is formed on at least one surface of the upper and lower surfaces of the waveguide film 10. The coating material of the reinforcement coating film may be used without limitation as long as it is a coating material capable of increasing the strength or / and surface hardness of the waveguide film. Hard coating materials are commercially available and detailed descriptions are omitted since they can be used. It is preferable to use curable resin.

In particular, it is preferable to select the material so that the reinforcing coating film has a refractive index smaller than that of the waveguide film. That is, since the refractive index of the reinforcing coating film is smaller than the refractive index of the waveguide film, the total reflection efficiency is increased, thereby guiding farther away to obtain a light emitting surface having improved uniformity.

The reinforcing coating film material for low refractive index may be included as long as the hard coating liquid having a refractive index smaller than that of the waveguide film. As an example, a hard coating solution made of 70-99.5% by weight of a hard coating solution based on solid content and 70-99.5% by weight of UV curable low refractive resin, a photoinitiator 0.05-5% by weight, and other additives of 0.45 to 25% by weight may be used.

Examples of the low refractive resin include a compound containing florin and silicon, but are not limited thereto. Low refractive resins are commercially available from 3M, DuPont, etc., including JSR, Japan. Low refractive resins can be thermally cured or UV cured. First, in the case of thermosetting, the compound contains a -CF2- repeating group in which the hydrogen position is replaced by florine, and is connected in the form of oxide, or when the cyclic structure, hydrogen is converted into florin. This is used. At this time, it is manufactured and sold to have a silicate functional group at the chain end to be cured by heat. In addition, it can be used by curing by using a fluoro carboxylic acid and a fluoro silane compound.

In the case of UV curing type, perfluoro acrylate / methacrylate containing acrylate / methacrylate group at the end for curing by ultraviolet rays, poly perfluoro urethane acrylate / methacrylate, fluoroacrylate / Monomers and oligomers such as methacrylates are commercially available, and in the case of oligomers, it is possible to include up to 2-10 hardenable functional groups, and using these polyfunctional oligomers can be used after giving excellent physical properties in advance. Implementation is possible.

The reinforcing coating film can be easily formed using a general known thin film manufacturing technology. That is, bar coating, roll coating, gravure, reverse gravure, etc. may be used, and the film may be prepared by spraying using a spray method to cure the film or to lower the pressure even if not in a vacuum to pass the film to the target location and low reflection It is also possible to apply a low-reflection coating in the form of deposition on the surface that needs to be. The thickness of the reinforcing coating film is not limited, but is preferably formed to a thickness of 1 ~ 200㎛.

The more preferable refractive index difference between the reinforcing coating film 11 and the waveguide film 10 is that the refractive index of the reinforcing coating film is 0.4 to 0.9 times the refractive index of the waveguide film. If it exceeds 0.9 times, the total reflection efficiency decreases, and if the refractive index difference is less than 0.4, an expensive material must be used, which is not preferable in terms of cost competitiveness.

In addition, as shown in FIGS. 3A to 3C, a dot (DOT) pattern is formed on the entirety of the upper surface (not shown) or the lower surface of the waveguide film on which the reinforcement coating layer 11 is formed or on the portion corresponding to the key region of the light emitting keypad. 12 can be formed. By forming the dot pattern, the light emission luminance of the region is increased. Therefore, as the dot pattern moves away from the light source, the dot pattern may be denser or increase in size, thereby obtaining uniform surface light emission. In addition, when the dot pattern is concentrated in a specific area, for example, an area of the position of the key, light emission is concentrated in the area of the key, so that the luminance is increased than the other area. In the case of the light-emitting keypad, it is more preferable to concentrate the dot pattern on the key area because light emission of the key area is important. However, the uniform dot pattern is not excluded from the present invention.

It is preferable that the said dot pattern is formed using curable resin composition. In particular, when using the curable resin composition excellent in hardness can be minimized the damage of the dot pattern. A well-known curable resin composition can be used as curable resin composition, A photocurable resin composition is especially preferable, A photoinitiator may be further included. In one example, an acrylic resin composition may be used. That is, the curable resin composition may be selectively applied to a position of a dot pattern and then cured. The curable resin composition used for the reinforcement protrusion mentioned later can also be used.

4 is a plan view of a waveguide film according to still another embodiment of the present invention, and FIGS. 5A to 5C are cross-sectional views of one embodiment, respectively.

As shown, the predetermined region of the upper portion (FIG. 4A) or the lower portion (FIG. 4B) of the waveguide film is characterized in that the reinforcement protrusions 13 formed by printing and curing the ink is provided.

In addition, by constructing the reinforcing protrusions 13 using the curing ink directly to the waveguide film, a layer for forming a separate protrusion is solved to solve the problem of thickening of the keypad, and a protrusion for improving the feeling of click on a very thin waveguide film. It is possible to give in a simple process, especially because the reinforcing protrusion is a hardened material having excellent hardness, durability is also increased.

The reinforcing protrusions 13 may be formed in a number to correspond to the positions of all or a part of the keys of the light emitting keypad. When the key is pressed by the user, the corresponding reinforcing protrusions 13 are pressed to thereby guide the waveguide film 10. The electrical connection is made easier in the switching part such as the dome switch which will be at the bottom of the.

The reinforcing protrusions 13 are formed by printing on a predetermined area using light or / and heat curing ink and then curing by applying light or / and heat. The reinforcing protrusions are not limited but may be formed to have a height (or thickness) within a range of 50 to 250 μm. Below the above range, the effect of the formation of reinforcing protrusions may be insignificant, and above the above range, the slimming effect is affected.

The reinforcing protrusions may be formed by printing and curing at one time, or may be formed by repeating the print-hardening process several times. In particular, when the height of the reinforcing projections is thick, it can be formed several times.

The photocurable ink for forming the reinforcing protrusions may be formed using a photocurable resin composition. In particular, it is possible to minimize the damage of the dot pattern when using a photocurable resin composition excellent in hardness. As the photocurable resin composition, a well-known photocurable resin composition may be used, and a photoinitiator is further included. As an example, UV curable acrylic hard coating materials such as polyester, acrylate, urethane acrylate and epoxy acrylate may be used, and may include colloidal silica particles, which are inorganic materials, as necessary, thereby improving high hardness and wear resistance.

In addition, a photocurable resin composition can be easily obtained on the market, and this can also be used. In addition, a silicone type ink can also be used.

In particular, the photocurable resin composition for forming the reinforcing protrusions may further include a light scattering agent to increase the luminance of the reinforcing protrusions forming position, that is, the key region. The light scattering agent may be an inorganic material or an organic material. For example, silicone, acrylic crosslinked fine particles, styrene crosslinked fine particles, methyl methacrylate-styrene crosslinked fine particles (MS-based crosslinked fine particles), calcium carbonate, barium sulfate, poly Carbonate-based resins, olefinic resins, titanium dioxide (TiO 2), silica (SiO 2) and the like can be used.

More preferably, the reinforcing protrusions 13 may be formed integrally with the reinforcing coating layer 11. That is, the same material may be formed by integrally applying and curing the waveguide film in the form of a reinforcing coating film and reinforcing protrusions. In this case, the manufacturing process is easy and the process time can be shortened. In addition, since the interface between the reinforcing coating layer and the reinforcing stone period does not exist, the reinforcing protrusion can be removed, and thus it is preferable.

6A and 6C are cross-sectional views of a light emitting keypad having a waveguide film according to an embodiment of the present invention. As shown, a key plate 20 having a plurality of keys formed thereon, a waveguide film of the above-described feature formed under the key plate, a light source 40 positioned on the side of the waveguide film to irradiate light onto the waveguide film, and Located on the lower portion of the waveguide film, it characterized in that it comprises a printed circuit board 30 having a dome switch (31, 32). The light source 40 is not limited, but LED is most preferred, the light source is located on the side of the waveguide film, can be selectively positioned among the bottom, top, left, right in the plan view of the keypad shown in FIG. It is good to exist. The waveguide film may use the above-described waveguide film, and since it has been described above in detail, description thereof will be omitted.

The key board 20 is not limited to the illustrated one, and all key board configurations known in the art are included. In addition, this invention does not limit the shape and material of a keypad. That is, each key of the keypad may be formed convexly, or may be formed of a flat plate and each key may be represented only by letters or numbers corresponding to the respective keys. Since it is well known in the art, detailed description thereof will be omitted.

Preferably, the keypad 20 is preferably made of a transparent flat sheet formed with the keys integrally. In addition, the keys may be expressed through the ink layer printing on the lower portion of the keypad, and the area except the keys may be colored by providing a colored deposition layer. In addition, the keypad may be formed with a protective coating layer to prevent scratches on the upper surface. In addition, the lower protrusion 21 may be present as shown in Figure 6a. In addition, an elastic layer made of a transparent rubber or silicone material or the like may be further added to the keypad for elasticity.

A lower portion of the waveguide film 10 may be coupled to a printed circuit board 30 having a dome switch, and the dome switch may be positioned to be spaced apart from the contact terminal on the contact terminal 32 and the contact terminal. It is preferable that the metal dome 31 is made of. The metal dome is a good elastic material is good for improving the clickability.

Therefore, when the keypad of the keypad is pressed by the user, the metal dome of the printed circuit board provided under the specific key is pressed so that the metal dome contacts and contacts the contact terminal.

The above embodiments are intended to describe the present invention in detail, and are not intended to limit the present invention, and thus modifications, modifications, omissions, etc. that can be applied within the scope of the technical idea of the present invention are defined by the claims. It is included in the scope of the invention.

1 is a perspective view of a general wireless terminal,

2 is a plan view of a waveguide film according to an embodiment of the present invention,

3A to 3C are cross-sectional views of a waveguide film according to one embodiment of the present invention;

4 is a plan view of a waveguide film according to another embodiment of the present invention;

5a to 5c are cross-sectional views of a waveguide film according to another embodiment of the present invention,

6A to 6C are cross-sectional views of a light emitting keypad according to another embodiment of the present invention.

** Description of the main symbols in the drawings **

10: waveguide film

11: reinforced coating film

12: dot pattern

13: reinforcement

20: key board

21: lower projection

30: printed circuit board

31: metal dome

32: contact terminal

40: light source

Claims (7)

It is a waveguide film for a light emitting keypad that guides the light incident from the light source to the surface light emitting, A reinforcement coating film is formed on at least one surface of the upper and lower surfaces of the waveguide film, and a dot (DOT) pattern for increasing luminance at a portion corresponding to the key region of the light emitting keypad on the upper or lower portion of the waveguide film on which the reinforcement coating film is formed. Waveguide film for light-emitting keypad formed. The waveguide film for a light emitting keypad according to claim 1, wherein the upper or lower portion of the waveguide film is provided with a reinforcing protrusion formed by printing and curing the cured ink on a portion corresponding to a key region of the light emitting keypad. The waveguide film of claim 2, wherein the reinforcing protrusions are integrally formed without an interface with the reinforcing coating layer. The waveguide film for a light-emitting keypad according to claim 3, wherein the height of the reinforcing protrusions is in a range of 50 to 250 µm. The waveguide film of claim 1, wherein the refractive index of the reinforcement coating film is smaller than that of the waveguide film. The waveguide film of claim 5, wherein the refractive index of the reinforcement coating film is 0.4 to 0.9 times the refractive index of the waveguide film. A key plate on which a plurality of keys are formed; The waveguide film of any one of claims 1 to 6 formed on the lower portion of the keypad; A light source positioned at a side of the waveguide film to irradiate light to the waveguide film; And And a printed circuit board positioned below the waveguide film and having a dome switch.

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