WO2005060117A1

WO2005060117A1 - Key button structure in mobile phone and method of manufacturing the same

Info

Publication number: WO2005060117A1
Application number: PCT/KR2004/000944
Authority: WO
Inventors: Jong Sun Bae
Original assignee: Ekolite Co. Ltd.
Priority date: 2003-12-18
Filing date: 2004-04-23
Publication date: 2005-06-30
Also published as: KR100458433B1

Abstract

Disclosed are a key button structure of a mobile phone and method for manufacturing the same. The key button structure includes a key injection element of an acryl material for holding the key button; a protruding layer for printing a protruding logo of an opaque color corresponding to a unique number of a corresponding key button on the front side of the key injection element; a shield layer formed on the rear side of the key injection element corresponding to the protruding logo, for shielding a light source toward portions except for a reverse logo that is set larger than the size of the protruding logo and a reverse letter for displaying the number of the key button; and a diffusion layer for providing a semi-transparent color of the reverse letter and diffusing the color of the reverse logo.

Description

KEY BUTTON STRUCTURE IN MOBILE PHONE AND METHOD OF MANUFACTURING THE SAME

Technical Field The present invention relates to a mobile phone keypad, and more particularly, to a key button structure of a mobile phone and method of manufacturing the same, wherein numbers or letters printed on the front of a keypad in a mobile phone are displayed in three dimensions when a pilot lamp is turned on, thus increasing a visual effect of a mobile phone design pattern.

Background Art Generally, a keypad is a switch device for generating a signal, which is used in communication devices such as mobile phones. Such a switch device has keys on which numbers, letters, etc. are printed. These keys are inserted into holes formed in the front housing of the communication device, wherein a part of these keys are protruded toward the outside of the front housing. Printed surfaces on which the numbers, letters or the like are printed are formed in the keys constituting the keypad. A user can press a desired key while viewing the numbers, letters, etc. printed in the printed surface. Further, a light source having a light- emitting device (LED) is disposed at the outer bottom of the keys so that the printed surfaces can be easily distinguished even at night. The user can distinguish the numbers, etc. printed in the keys due to a backlighting effect when the light source illuminates the light. FIG. 1 is a cross-sectional view illustrating the construction of a keypad in a mobile phone in a related art. A key 101 constituting a keypad of a mobile phone includes a base 107, a key top 105 that is upwardly protruded from the base 107, and a protrusion unit 113 formed at the central bottom of the key top 105. The base 107 and the key top 105 are integrally connected by means of a connection element 121. The connection element 121 has a tliinner thickness than the base 107 so that the key 101 operates smoothly. A printed surface 103 in which numbers or letters are printed by means of a silkscreen printing machine or a laser-marking machinery, is formed on the key top 105. Furthermore, a groove 109 of a predetermined size is formed at the bottom of the base 107. A LED 111 disposed on a printed circuit board 119 is disposed in the groove 109, whereby the user can easily view the printed surface 103 even at a dark place. A dome switch 117 having a predetermined elastic strength is located below the protrusion unit 113. A fixed contact point 115 that is protruded on the printed circuit board 119 is disposed under the central of the dome switch 117. In such a keypad, if a folder or flip (not shown) of the mobile phone is opened, the power is applied to the LED 111, which provides the backlighting to the keypad. Thus, the user can see the printed surface 103 formed on the key top 105 even at a dark place. Further, if the folder or flip is shut, the power applied to the LED 111 is cut off and the backlighting is thus stopped. Such back lighting of the mobile phone becomes an important factor to determine a fine view of the mobile phone in addition to a functional means. Recently, in order to satisfy a variety of design patterns and a visual effect while increasing a product added value of a keypad, a keypad using a so-called plating key on which a metal material is covered on the surface of the keypad by means of a plating or spray method, has been used. Such a conventional keypad, however, is oriented to a design that highlights the beauty of the appearance. Thus, as intensity of illumination generated from the LED does not retain up to the printed surface intact, there is a functional problem that the printed surface is not clearly seen.

Disclosure of Invention Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a key button structure of a mobile phone and method of manufacturing the same, wherein letters of a printed surface are displayed in three dimensions when a mobile phone keypad is back lighted, thus allowing a user to easily manipulate the keypad and maximizing an added value of a product due to highlighted beauty of the appearance of the mobile phone. To achieve the above objects, according to a first aspect of the present invention, there is provided a key button structure mounted in a front panel of a mobile phone, including a key injection element of an acryl material for holding the key button; a protruding layer for printing a protruding logo of an opaque color corresponding to a unique number of a corresponding key button on the front side of the key injection element; a shield layer formed on the rear side of the key injection element corresponding to the protruding logo, for shielding a light source toward portions except for a reverse logo that is set larger than the size of the protruding logo and a reverse letter for displaying the number of the key button; and a diffusion layer for providing a semi- transparent color of the reverse letter and diffusing the color of the reverse logo. It is preferred that the key injection element corresponding the protruding logo is printed between the shield layer and the rear portion of the key injection element, and the reverse logo is larger than the protruding logo, and the background layer provides a characters of the key button with background color. Also, the acryl material is one of polycarbonate, acryl, ABS (Acrylonitrile Butadiene Styrene), and has transmittance of 85% to 91 %. In the above, the reverse logo has a figure whose size is amplified by 0.2mm than the size of the protruding logo, and has a tolerance of 0.2mm. Also, the shield layer is a printing layer using a silver colors, or using a general colors composed with at least 10% luster ink. Furthermore, the shield layer includes a first shield layer for printing a white family color, a second shield layer for printing a black family color on the first shield layer, and a third shield layer for printing a white family color on the second shield layer. In addition, the shield layer includes a first shield layer for printing a gray family color, and a second shield layer for printing a black family color on the first shield layer. According to a second aspect of the present invention, there is provided a method for printing a logo of the key button according to claim 1 or 7, including the steps of a) printing a protruding logo of an opaque color corresponding to a unique number of a corresponding key button on the front side of a key injection element holding the key button; b) printing a shield layer for shielding a light source toward portions except for a reverse logo that is set larger than the size of the protruding logo and a reverse letter for displaying the number of the key button, on the rear side of the key injection element corresponding to the protruding log; and c) printing a diffusion layer for providing a semi-transparent color of the reverse letter and diffusing a color of the reverse logo.

Brief Description of Drawings Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: FIG. 1 is a cross-sectional view illustrating the construction of a keypad in a mobile phone in a related art; FIG. 2 is a perspective view illustrating a key injection element of a keypad in a mobile phone according to the present invention; FIG. 3 is a flowchart illustrating steps for embodying a method of printing a key button according to the present invention; FIG. 4 is a perspective view shown to explain, by the layer, the printing method described with reference to FIG. 3; and FIG. 5 is a cross-sectional view illustrating a printing layer by the layer shown in FIG. 4.

BESTMODEFORCARRYING OUT THEINVENTION The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings. FIG. 2 is a perspective view illustrating a key injection element 200 made from polycarbonate, acryl or ABS materials, which is injected on a flat acryl panel of a predetermined shape by suing a key-shaped mold of a mobile phone according to the present invention. It is preferred that the key injection element 200 is 1mm in thickness and is made from a general-purpose acryl material having thermal resistance (-40°C to 135°C) and with no deformation. The element 200 has transmittance of 85% to 91% and can be silk-screen printed. In particular, the key injection element 200 used in the present invention has a rear gate portion, which is flat with no prominence and depression, and has a low reflectivity light source. The key injection element 200 includes a frame 201 of a predetermined shape for receiving a plurality of key buttons 205 used in the mobile phone, and a rib 203 by the key button 205, for connecting the frame 201 and the plurality of the key buttons 205 to form an integrated projection mold. Furthermore, the key injection element 200 can be mass-produced on the flat acryl panel by means of a projection mold process. FIG. 3 is a flowchart shown to explain the process of printing on the key injection element according to the present invention, and FIG. 4 is a perspective view illustrating a printing layer that is colored on the key injection element. A flat acryl material such as polycarbonate of a transparent material, an ABS resin, an acryl resin and the like is injected by using a mold depending on a key shape of a mobile phone (S301). In the above, it is preferable that the flat acryl material is made from a transparent material having transmittance of 85%> to 91%) and a general-purpose acryl material or polycarbonate having thermal resistance of -40°C to 135°C. A large number of the key injection elements 200 injected thus are seated onto a silkscreen jig and then each fixed with a minimum tolerance. The fixed key injection elements 200 are each fixed by another jig without movements. A film process or a plate making process for logos and letters to be printed on the key injection elements 200 are performed. In the above, the film is a film designed by each layer that is printed on the front and rear sides of the key injection element 200. Each plate making process is performed through a corresponding film by the layer. That is, as shown in FIG. 4, each plate making process for printing a protruding logo 411 on the key button 205 and a shield layer 415 below the key button 205, is performed. A film based on a separation process by the layer every a previously set design, i.e., design of the protruding logo 411 and a predetermined color for forming the shield layer 415, is first manufactured. The plate making process includes covering an emulsion on a mesh such as a polyester mesh, a nylon mesh, a SUS (Steel Use Stainless) mesh of over 300 to 350 mesh or the like for the exactness of a printing logo, and then drying the mesh. Next, the film is laid on the dried mesh and is then illuminated by ultraviolet (U.V.) rays, whereby a graphic shape corresponding to a graphic by the layer and the logo are removed. The film is removed by spraying water of a high pressure to each screen manufactured thus by using a spray gun. Therefore, the graphic formed by each layer is created on each screen in a reverse form. If the plate making process is completed, then a corresponding film is seated on the front side of the key injection element 200 and a plurality of protruding logos 411 by the plurality of the key buttons 205 corresponding to the design of the film are printed (S303). Furthermore, the background layer (402) is printed (S304), then the corresponding film is seated on the rear side of the key injection element 200. The shield layer 415 and a diffusion layer 409 corresponding to the design of the film are then printed (S315 and S311). In the above, the shield layer 415 is for shielding the light of the LED or the

Organic EL (Electro Luminescence) mounted in the bottom of the keypad. The shield layer 415 may be formed by printing a colors of a silver color in a predetermined thickness. In order to increase the shielding capability, a first shield layer 403 of the white color may be printed (S305), a second shield layer 405 of the black color may be printed (S307) and a third shield layer 407 of the white color may be printed (S309), as needed. At this time, it is to be noted that the respective shield layers may have colors different from the above colors and the same effects as the present invention can be obtained even when a single shield layer or a multiple shield layer of the gray color or black color is formed. Further, the shield layer 415 is printed by a predetermined thickness using a composed general colors with luster ink. Meanwhile, by using the shield layer 415 instead of the background layer 402, it has an additional function of producing a background color of the key button 205 and transferring the light to the protruding logo 411 of the protruding layer 401. In other words, a shape of a logo that is reverse to the protruding logo 411 is printed on each shield layer of a location corresponding to the protruding logo 411. This is for shielding the remaining portions other than the reverse logo 413. A portion of the light source supplied from the LED is scanned to the protruding logo 411 through the reverse logo 413 of the shield layer 415. In the above, the reverse logo 413 has a size of 0.2mm greater than the protruding logo 411 (the tolerance is 0.2mm). It is preferred that a ground color printing by the shield layer 415 includes a silkscreen printing using a solvent inlc for the shielding capability. Through the above process, respective numbers corresponding to the keypads are printed on the front side of the key injection element 200 as the protruding logo 411 of an opaque color. A ground color except for a reverse letter 417 and the reverse logo 413 including respective letters and symbols corresponding to the keypad is printed on the rear side of the key injection element 200. Thereafter, a color for displaying a logo at a location where the reverse letter 417 and the reverse logo 413 formed on the rear side of the key injection element 200 are shown, is printed. This enables a three-dimensional effect to be obtained by the reverse logo 413 of a diffusion layer 409 printed on the rear side of the protruding logo 411. In other words, as shown in FIG. 5, after the protruding logo 411 is printed on the front side of the key button 205, a plurality of shield layers 415 are formed on the rear side of the key button 205, wherein each shield layer 415 excludes the reverse logo 413 and the reverse letter 417. Also, the shape of the reverse logo 413 is amplified so that the reverse logo 413 and the protruding logo 411 have a gap (a) of about 0.2mm. Thereafter, the diffusion layer 409 is printed so that the reverse logo 413 is visually diffused through light divergence. The diffusion layer 409 can be subject to the silk printing including diffusion ink. In manufacturing a base (not shown) of a rubber material for fixing the respective key buttons 205, the printing of the diffusion layer 409 may be omitted by chemically mixing the rubber material and the diffusion ink as a fluorescence so that it works a fluorescence effect. Meanwhile, the diffusion layer 409 corresponding to the reverse letter 417 is experienced by a printing process of a predetermined color at a location corresponding to the reverse letter 417, so that the diffusion layer 409 has a predetermined color. The printing process is thus completed. Thereafter, a rib of the key injection element 200 is cut. The cutting is a laser cutting using a predetermined jig. If such laser cutting is used, damages of the key can be minimized and alien substances layer can be more completely removed. Further, a small amount of an adhesive is discharged onto the rear side of the key button 205 through an adhesive discharge device. An assembly process of adhering silicon or film-insertion type base (not shown), which was previously manufactured through an additional keypad manufacturing process, and the key button 205, is performed. The key button 205 completed through the printing process is experienced by full hardness dry through ultraviolet scanning for U.V. coating on the top and bottom of the key button 205 (S313). It is preferred that the dry condition is 65°C/minute. Such dry condition prevents the pattern printed on the top and bottom of the key button 205 from being erased and scratched. In the mobile phone key constructed as above, the light source of the LED or organic EL that is turned on when the mobile phone is operated is scanned to the shield layer 415 through the diffusion layer 409 or the base including the diffusion ink. The light source through the shield layer 415 is^scanned to the protruding logo 411 through the key button 205 of the acryl material. At this time, there occurs diffused reflection wherein a portion of the light source is reflected by the protruding logo 411 and is again reflected to the reverse logo 413. Accordingly, the brightness of the reverse logo 413 is increased and the contrast with the protruding logo 411 is enhanced, whereby an optical illusion in which the protruding logo 411 is seen with it protruded by some degree occurs.

Industrial Applicability According to the present invention described above, a large number of flat key injection elements made from a transparent acryl material are injected. In this case, protruding logos corresponding to numbers of keypads are printed on the top of key buttons. A reverse logo and a reverse letter are formed at the rear location of the key button corresponding to the protruding logo. A background color of the key button is printed on the remaining portions except for the reverse logo and the reverse letter and a shield layer for shielding the light source is printed at the same time. A diffusion layer for diffusing the color of each reverse letter and reverse logo is printed, wherein the reverse logo is diffused about 0.2mm compared to the protruding logo. Thus, the protruding logo is displayed in three dimensions by means of a reflecting light source of the reverse logo by means of the light source of a LED that is turned on when the mobile phone is used. Therefore, the present invention has effects that a user can easily manipulate a keypad, the beauty of a mobile phone is enhanced and a visual image of a mobile phone design pattern is upgraded regardless of surrounding illumination. While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.

Claims

What Is Claimed Is:

1. A key button structure mounted in a front panel of a mobile phone, comprising: a key injection element of an acryl material for holding the key button; a protruding layer for printing a protruding logo of an opaque color corresponding to a unique number of a corresponding key button on the front side of the key injection element; a shield layer printed on the rear side of the key injection element corresponding to the protruding logo, for shielding a light source toward portions except for a reverse logo that is set larger than the size of the protruding logo and a reverse letter for displaying the number of the key button; and a diffusion layer for providing a semi-transparent color of the reverse letter and diffusing the color of the reverse logo.

2. The key button structure as claimed in claim 1, wherein the acryl material is one of polycarbonate, acryl, ABS, and has transmittance of 85% to 91%.

3. The key button structure as claimed in claim 1, wherein the key injection element corresponding the protruding logo is printed between the shield layer and the rear portion of the key injection element, and the reverse logo is larger than the protruding logo, and the background layer provides a character of the key button with background color.

4. The key button structure as claimed in claim 1, wherein the reverse logo has a figure whose size is amplified by 0.2mm than the size of the protruding logo, and has a tolerance of 0.2mm.

5. The key button structure as claimed in claim 1, wherein the shield layer is a printing layer using a silver colors or a general colors composed with at least 10% luster ink.

6. The key button structure as claimed in claim 1, wherein the shield layer comprises a first shield layer for printing a white family color, a second shield layer for printing a black family color on the first shield layer, and a third shield layer for printing a white family color on the second shield layer.

7. The key button structure as claimed in claim 1, wherein the shield layer comprises a first shield layer for printing a gray family color, and a second shield layer for printing a black family color on the first shield layer.

8. The key button structure as claimed in claim 1, wherein the shield layer comprises the first shield layer and the second shield layer which is the same colors so that a single layer of black family colors is formed on it or a double layer of black family colors is formed on it.

9. A key button structure mounted in a front panel of a mobile phone, comprising: a key injection element of an acryl material for holding the key button; a protruding layer for printing a protruding logo of an opaque color corresponding to a unique number of a corresponding key button on the front side of the key injection element; a shield layer formed on the rear side of the key injection element corresponding to the protruding logo, for shielding a light source toward portions except for a reverse logo that is set larger than the size of the protruding logo and a reverse letter for displaying the number of the key button; a diffusion layer for providing a semi-transparent color of the reverse letter; and a base of a rubber material for fixing the key button at a given location, wherein the base chemically contains diffusion ink for diffusing the light source that is projected to the reverse logo.

10. The key button structure as claimed in claim 9, wherein the acryl material is one of polycarbonate, acryl, ABS, and has transmittance of 85% to 91 %.

11. The key button structure as claimed in claim 9, wherein the key injection element corresponding the protruding logo is printed on between the shield layer and the rear portion of the key injection element, and the reverse logo is larger than the protruding logo, and the background layer provides a character of the key button with background color.

12. The key button structure as claimed in claim 9, wherein the reverse logo has a figure whose size is amplified by 0.2mm than the size of the protruding logo, and has a tolerance of 0.2mm.

13. A method for printing a logo of the key button according to claim 1 or 9, comprising the steps of: a) printing a protruding logo of an opaque color corresponding to a unique number of a corresponding key button on the front side of a key injection element holding the key button; b) printing a shield layer for shielding a light source toward portions except for a reverse logo that is set larger than the size of the protruding logo and a reverse letter for displaying the number of the key button, on the rear side of the key injection element corresponding to the protruding log; and c) printing a diffusion layer for providing a semi-transparent color of the reverse letter and diffusing a color of the reverse logo.

14. The method as claimed in claim 13, further comprising d) a full hardness dry step of a printed state of the key button using ultraviolet rays (U.V).

15. The method as claimed in claim 13, further comprising the printing step which provides the background color for character of the key button and the reverse logo which is formed larger size than that of the protruding logo.

16. The method as claimed in claim 13, wherein the dry step is performed at a temperature of 65 °C for 1 minute.

17. The method as claimed in claim 13, wherein the reverse logo has a figure whose size is amplified by 0.2mm than the size of the protruding logo, and has a tolerance of 0.2mm.

18. The method as claimed in claim 13, wherein in step b), a silver colors or a general colors composed with at least 10%) luster ink is used.

19. The method as claimed in claim 13, wherein the step b) comprises the steps of: b- 1 ) printing a white family color, b-2) printing a black family color after step b-1), and b-3) printing a white family color after step b-2).

20. The method as claimed in claim 13, wherein the step b) comprises the steps of: b-1) printing a gray family color, and b-2) printing a black family color after step b-1).

21. The method as claimed in claim 13, wherein the step b), the first shield layer and the second shield layer which is the same colors so that a single layer of black family colors is formed on it or a double layer of black family colors is formed on it.