KR100797645B1 - Apparatus for illuminating keypad - Google Patents

Abstract

An apparatus for keypad lighting according to the present invention includes: a light guide plate through which light travels; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; At least one light emitting element disposed to face a side surface of the light guide plate, and configured to couple light into the light guide plate; And a switch substrate having at least one switch formed on an upper surface of the light guide plate, wherein the portion of the light guide plate deformed toward the switch substrate presses the switch according to a user's pressing, and the light guide plate has a self restoring force. In the deformation after the deformation is restored.

Key pad, elastic pad, backlight, light emitting diode, switch

Description

Keypad lighting device {APPARATUS FOR ILLUMINATING KEYPAD}

1 is a cross-sectional view showing a keypad assembly according to the prior art,

2 is a cross-sectional view showing a keypad assembly according to a first embodiment of the present invention;

3 is a view showing examples of the projection according to the present invention,

4 is a view showing a reflection pattern shown in FIG.

5 is a view showing various configuration examples of a light emitting device according to the present invention;

6 is a cross-sectional view showing a keypad assembly according to a second embodiment of the present invention;

7 is a cross-sectional view showing a keypad assembly according to a third embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keypad provided in a portable terminal and the like, and more particularly, to a keypad and a keypad assembly having a light guide panel.

Key pads used in conventional portable terminals include an elastic pad having a plate shape, a plurality of key buttons formed on an upper surface of the elastic pad, each of which has letters printed on the upper surface thereof; It includes a plurality of protrusions (or actuators) formed on the lower surface of the elastic pad located opposite the upper surface. In addition, the portable terminal typically has a plurality of light emitting devices (typically about 15 to 20) for backlighting the keypad.

1 is a cross-sectional view showing a keypad assembly according to the prior art. The keypad assembly 100 includes a keypad 110, a switch board 150, and a plurality of light emitting diodes (LEDs) 170.

The key pad 110 is formed on the elastic pad 120 having a plate shape, a plurality of key buttons 140 formed on the upper surface 122 of the elastic pad 120, each of which is printed letters and the like on the upper surface; And a plurality of protrusions 130 formed on the bottom surface 124 of the elastic pad 120 positioned opposite to the top surface 122. The protrusion 130 is aligned at the center of each key button 140. A plurality of grooves 126 may be formed on the bottom surface 124 of the elastic pad 120. The grooves 126 are disposed around the protrusions 130 and are formed to avoid interference between the light emitting diodes 170 and the protrusions 130.

The switch substrate 150 includes a printed circuit board (PCB) 155 having a plate shape and a plurality of switches formed on an upper surface of the printed circuit board 155 facing the keypad 110. 160). Each switch 160 includes a conductive contact member 162 and a conductive dome 164 completely covering the contact member 162.

The plurality of light emitting diodes 170 are mounted on an upper surface of the printed circuit board 155, and each of the light emitting diodes 170 is positioned to be covered by a corresponding groove 126 of the elastic pad 120. .

When the user presses any one key button 140, the portion of the keypad 110 located below the key button 140 is deformed toward the switch substrate 150, so that the corresponding belonging to the deformed portion Protrusion 130 is pressed on the dome 164. The depressed dome 164 is in electrical contact with the contact member 162.

For the operation of the switches 160, each light emitting diode 170 may not be positioned under the corresponding key button 140. Since the light output from each of the light emitting diodes 170 passes through the elastic pad 120 to illuminate the key button 140 in a square, there is a problem that the illumination of the key button 140 is uneven and dark. That is, the central portion of each key button 140 is relatively dark, and the edge portion of the key button 140 is relatively bright. In addition, in order to illuminate the key buttons 140 uniformly and brightly, when a larger number of light emitting diodes are installed, there is a problem in that power consumption is increased and manufacturing costs are increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a device for keypad lighting, a keypad and a keypad assembly, which can realize uniform high brightness, low power consumption and low manufacturing cost. Is in.

In order to solve the above problems, the keypad lighting apparatus according to the first aspect of the present invention, the light guide plate through which the light propagates therein; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; At least one light emitting element disposed to face a side surface of the light guide plate, and configured to couple light into the light guide plate; And a switch substrate having at least one switch formed on an upper surface of the light guide plate, wherein the portion of the light guide plate deformed toward the switch substrate presses the switch according to a user's pressing, and the light guide plate has a self restoring force. In the deformation after the deformation is restored.

In addition, the keypad lighting apparatus according to the second aspect of the present invention, the light guide plate through which the light propagates therein; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; A dome sheet disposed below the light guide plate and having a plurality of conductive domes, wherein the reflection pattern causes diffuse reflection.

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Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; In describing the present invention, detailed descriptions of related well-known functions and configurations are omitted in order not to obscure the subject matter of the present invention.

2 is a cross-sectional view showing a keypad assembly according to a first embodiment of the present invention. The keypad assembly 200 includes a keypad 210, a switch substrate 250 spaced apart from the keypad 210, at least one light emitting device 290, and a second printed circuit board 280. ).

The keypad 210 is indicated by a light guide plate 220, a plurality of key buttons 245, a plurality of protrusions 240, and a plurality of reflective patterns 230 (filled with black triangles). ).

The light guide plate 220 guides light coupled into the light guide plate 220. The combined light travels from one side of the light guide plate 220 to the other side. The light guide plate 220 may have an arbitrary shape such as a square plate, and the light coupled into the light guide plate 220 may be formed by total reflection at a boundary between the light guide plate 220 and an air layer outside the light guide plate 220. The light guide plate 220 proceeds to the inside. The light guide plate is elastic, so that the key button 245 is returned to its original position after being pressed. That is, the light guide plate 220 has a self restoring force and is restored to a circular shape after deformation, and restores the key button 245 to its original position after the key button 245 is operated.

Conventional light guide plates are manufactured by injection molding polycarbonate or acrylic resin that has high transmittance to visible light, and these light guide plates have a low elastic strain and a low elastic restoring force and high hardness when a key button is pressed. It is difficult to obtain a good click feeling of, and when one key button is pressed, adjacent key buttons operate simultaneously (interference between the key buttons) or permanent deformation is likely to occur during repetitive operation.

Thus, the light guide plate 220 provides a good click feeling, suppresses the interference between the key buttons 245, and has a low hardness, high elastic strain, high elastic restoring force and high light so that permanent deformation does not occur even in repeated operation. Characterized in that it is formed of a highly transparent rubber material having a permeability, preferably formed of a material such as polyurethane (polyurethane), silicon (silicone).

The plurality of key buttons 245 are formed on the upper surface 222 of the light guide plate 220, and letters, numbers, and the like are printed on the upper surfaces of the light guide plates 220, respectively. The key buttons 245 may be formed in one piece or the same as or different from that of the light guide plate 220, or may be formed of a material such as polycarbonate or acrylic resin, and then formed on the top surface 222 of the light guide plate 220. Can be attached. Each key button 245 may have any shape such as a circle column, an ellipse column, and the like.

The plurality of protrusions 240 are formed on the lower surface 224 of the light guide plate 220 positioned opposite to the upper surface 222. The protrusions 240 may be integrally formed with the same or different material as the light guide plate 220 or may be separately formed and attached to the bottom surface 224 of the light guide plate 220. Each of the protrusions 240 may have an arbitrary shape such as a truncated cone, a trapezoidal cube, or the like. Each of the protrusions 240 is aligned below the corresponding key button 245 (in a thickness direction of the keypad assembly 200 or in a direction perpendicular to an upper surface of the first printed circuit board 260).

3 is a view showing examples of the projection according to the present invention. FIG. 3A shows the projection 310 having an ellipsoidal top and bottom surfaces 312 and 316 and an inclined truncated conical shape, and the upper and lower surfaces 322 and 326 are rectangular. Four sides 324 represent a projection 320 having a trapezoidal hexahedron shape.

The keypad 210 is formed on the bottom surface of the light guide plate 220 and has a plurality of reflective patterns 230 reflecting a part of light traveling into the light guide plate 220 toward the corresponding key button 245. If necessary, the reflective pattern may be formed on the upper surface of the light guide plate 220. Each of the reflective patterns 230 is formed around the protrusion 240 and the protrusion 240 positioned directly below the key button 245 to enable uniform illumination of the key button 245. In addition, in the entire keypad 210, the light guide plate 220 may be different from the density or size of the reflective pattern positioned relatively close to the light emitting device 290 by varying the density or size of the reflective pattern positioned relatively far away. The overall light quantity distribution emitted to the upper side of the) can be uniformly adjusted regardless of the distance to the light emitting element 290. For example, based on the light emitting element 290, when the amount of emitted light at a relatively close position is relatively high, the density of the reflection pattern at a relatively close position is made low, and the amount of emitted light at a relatively distant position is low. When the density is relatively small, the density of the reflection pattern at a relatively distant position can be made high, thereby making it possible to uniformly brighten the overall distribution of emitted light, that is, the overall illumination distribution of the key buttons 245.

4 is a view showing a reflection pattern according to the present invention. The central portion 232 of the reflective pattern 230 is formed on the bottom surface of the protrusion 240, and the edge portion 234 of the reflective pattern 230 is formed around the protrusion 240. As shown, light that totally reflects into the light guide plate 220 is incident on the reflective pattern 230, and most of the light that is diffusely reflected to the key button 245 by the reflective pattern 230 does not satisfy the total reflection condition. If the incident angle is smaller than the critical angle, the light is transmitted through the key button 245 and exits to the outside. In addition, some of the light that is excessively reflected without being reflected by the reflective pattern 230 and the part of the light that is diffusely reflected continue to the light guide plate 220 while satisfying the total reflection condition, thereby contributing to illuminating another key button. That is, the reflection pattern 230 causes diffuse reflection so that only a part of the incident light is used to illuminate the key button 245 and the rest of the incident light is used to illuminate another key button. In addition, the reflective pattern 230 implements uniform illumination of the key button 245 through diffuse reflection in an arbitrary direction. Preferably, the reflective pattern 230 may be formed by scratching, printing, or the like.

In addition, as shown in FIG. 2, the central portion 232 ′ (indicated by an unfilled triangle) of the reflective pattern 230 is not the lower surface of each of the protrusions 240, but the light guide plate 220 and the It may be formed between the projections 240.

The switch substrate 250 includes a first printed circuit board 260 and a dome sheet 270.

The first printed circuit board 260 includes a plurality of conductive contact members 265 formed on an upper surface of the first printed circuit board 260, and each of the contact members 265 forms a switch 265 and 275 together with a corresponding dome 275. In addition, the switches 265 and 275 are arranged under the corresponding protrusion 240.

The dome sheet 270 is attached to an upper surface of the first printed circuit board 260 and includes a plurality of conductive domes 275 having a hemispherical shape, and each dome 275 has a corresponding contact member 265. Completely cover it.

When a user presses any one key button 245, a portion of the keypad 210 positioned below the key button 245 is deformed toward the switch substrate 250, thereby corresponding to the deformed portion. The protrusion 240 presses the corresponding dome 275. The pressed dome 275 is in electrical contact with the contact member 265.

The second printed circuit board 280 is attached to an edge portion of the lower surface 224 of the light guide plate 220, and the at least one light emitting element 290 is opposite to the side surface of the light guide plate 220 and the light emitting surface thereof. It is mounted on the upper surface of the second printed circuit board 280 so as to. The light emitted from the light emitting element 290 is coupled to the inside through the side surface of the light guide plate 220. As the second printed circuit board 280, a conventional flexible printed circuit board (FPCB) may be used, and as the light emitting device, a conventional light emitting diode may be used.

5 is a view showing various configuration examples of the light emitting device according to the present invention. FIG. 5A is a front view illustrating a case in which the light emitting device 410 is disposed at the center of the side surface of the light guide plate 401, and FIG. 5B illustrates the light emitting device 420 at an edge of the light guide plate 402. It is a front view which shows the case. 5C illustrates a case in which the first and second light emitting devices 430 and 435 are spaced apart from each other on the side of the light guide plate 403, and a plurality of key buttons 404 are attached to the light guide plate 403. It is a front view showing.

As illustrated, the light emitting element according to the present invention may be disposed at any position, in any number as necessary.

6 is a cross-sectional view showing a keypad assembly according to a second embodiment of the present invention. The keypad assembly 200 ′ has a configuration similar to that of the keypad assembly 200 illustrated in FIG. 2, but differs only in the shape of the light guide plate 220 ′ and the position of the light emitting device 290 ′. Therefore, the same reference numerals are used for the same components, and overlapping descriptions will be omitted.

The light guide plate 220 ′ generally has a rectangular plate shape and guides light coupled therein. The light guide plate 220 ′ has one edge portion 226 inclinedly extended to the top surface of the printed circuit board 260.

At least one light emitting element 290 ′ is mounted on an upper surface of the printed circuit board 260 such that a light emitting surface thereof faces a side surface of the inclined portion 226 of the light guide plate 220 ′. Light emitted from the light emitting element 290 ′ is coupled to the inside of the light guide plate 220 ′ through the side surface of the light guide plate 220 ′.

Compared to the first embodiment described above, in the second embodiment, the flexible printed circuit board for wiring the light emitting element 290 'is not required by changing the shape of the light guide plate 220', so that the keypad There is an advantage that the assembly 200 'can be implemented more economically.

7 is a cross-sectional view showing a keypad assembly according to a third embodiment of the present invention. The keypad assembly 200 ″ has a configuration similar to that of the keypad assembly 200 illustrated in FIG. 6, but differs only in the shape of the light guide plate 220 ″. Therefore, the same reference numerals are used for the same components, and overlapping descriptions will be omitted.

The light guide plate 220 ″ has a rectangular plate shape having a constant thickness, and guides light coupled therein. The light guide plate 220 ″ is bent such that one side edge portion 226 ′ extends to the top surface of the printed circuit board 260. That is, since the light guide plate 220 ″ may be made of a rubber material such as silicon, the light guide plate 220 ″ may be used for optical connection between the light guide plate 220 ″ and the light emitting device 290 ′ having different vertical positions. One side edge portion 226 ′ of 220 ″ may be bent as shown.

The light emitting device 290 ′ is mounted on an upper surface of the printed circuit board 260 such that a light emitting surface thereof faces a side surface of one side edge portion 226 ′ of the light guide plate 220 ″. Light emitted from the light emitting element 290 ′ is coupled to the inside of the light guide plate 220 ″.

As described above, the apparatus for keypad illumination, the keypad and the keypad assembly according to the present invention has an advantage that the key buttons can be uniformly and brightly illuminated by having an elastic light guide plate between the key buttons and the projections. have. In addition, since the keypad and the keypad assembly include a light guide plate, there is an advantage in that the number and power consumption of light emitting devices required can be reduced, and manufacturing costs can be reduced.

Claims (74)

delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete In the keypad lighting device, A light guide plate through which light propagates therein; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; At least one light emitting element disposed to face a side surface of the light guide plate, and configured to couple light into the light guide plate; It includes a switch substrate having at least one switch formed on the upper surface facing the light guide plate, As the user presses, the portion of the light guide plate deformed toward the switch substrate presses the switch, The light guide plate has a self restoring force and is restored to a circular shape after deformation, Keypad lighting device, characterized in that the material of the light guide plate is polyurethane or silicon. The method of claim 29, Keypad illumination device, characterized in that the density or size of the reflective pattern is changed in order to uniformly adjust the overall light quantity distribution emitted to the outside of the light guide plate. delete delete The method of claim 29, And the reflective pattern causes diffuse reflection. The method of claim 29, And the reflective pattern is formed on an upper surface or a lower surface of the light guide plate. In the keypad lighting device, A light guide plate through which light propagates therein; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; A dome sheet disposed below the light guide plate and having a plurality of conductive domes; The reflection pattern causes diffuse reflection, Keypad lighting device, characterized in that the material of the light guide plate is polyurethane or silicon. 36. The method of claim 35 wherein Keypad illumination device, characterized in that the density or size of the reflective pattern is changed in order to uniformly adjust the overall light quantity distribution emitted to the outside of the light guide plate. Claim 37 was abandoned upon payment of a registration fee. 36. The method of claim 35 wherein The light guide plate has a self-healing force, and the keypad lighting device, characterized in that restored to the circular shape after deformation. delete delete 36. The method of claim 35 wherein And the reflective pattern is formed on an upper surface or a lower surface of the light guide plate. 36. The method of claim 35 wherein And at least one light emitting element disposed to face the side of the light guide plate and coupling light into the light guide plate. delete The method of claim 29, wherein the switch substrate, A printed circuit board having a plurality of conductive contact members formed on an upper surface thereof; And a dome sheet attached to an upper surface of the printed circuit board and having a plurality of conductive domes. Claim 44 was abandoned upon payment of a set-up fee. The method of claim 43, The light emitting device is a keypad lighting apparatus, characterized in that installed on one side of the printed circuit board. delete In the keypad lighting device, A light guide plate through which light propagates therein; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; At least one light emitting element disposed to face a side surface of the light guide plate, and configured to couple light into the light guide plate; It includes a switch substrate having at least one switch formed on the upper surface facing the light guide plate, In order to uniformly adjust the overall light quantity distribution emitted to the outside of the light guide plate, the density or size of the reflective pattern is varied, Keypad lighting device, characterized in that the material of the light guide plate is polyurethane or silicon. Claim 47 was abandoned upon payment of a registration fee. 47. The method of claim 46 wherein The light guide plate has a self-healing force, and the keypad lighting device, characterized in that restored to the circular shape after deformation. delete delete delete 47. The method of claim 46 wherein And the reflective pattern causes diffuse reflection. 47. The method of claim 46 wherein And the reflective pattern is formed on an upper surface or a lower surface of the light guide plate. The method of claim 46, wherein the switch substrate, A printed circuit board having a plurality of conductive contact members formed on an upper surface thereof; And a dome sheet attached to an upper surface of the printed circuit board and having a plurality of conductive domes. Claim 54 was abandoned upon payment of a setup registration fee. The method of claim 53, The light emitting device is a keypad lighting apparatus, characterized in that installed on one side of the printed circuit board. In the keypad lighting device, A light guide plate through which light propagates therein; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; A switch substrate disposed under the light guide plate, the printed circuit board comprising a plurality of conductive contact members formed on an upper surface thereof, and a dome sheet attached to an upper surface of the printed circuit board and having a plurality of conductive domes; At least one light emitting device provided on one side of the printed circuit board to face the side of the light guide plate, The reflection pattern causes diffuse reflection, Keypad lighting device, characterized in that the material of the light guide plate is polyurethane or silicon. Claim 56 was abandoned upon payment of a setup registration fee. The method of claim 55, The light guide plate has a self-healing force, and the keypad lighting device, characterized in that restored to the circular shape after deformation. delete delete delete The method of claim 55, And the reflective pattern is formed on an upper surface or a lower surface of the light guide plate. The method of claim 55, Keypad illumination device, characterized in that the density or size of the reflective pattern is changed in order to uniformly adjust the overall light quantity distribution emitted to the outside of the light guide plate. The method of claim 29, An edge portion of the light guide plate extends on the switch substrate. 47. The method of claim 46 wherein An edge portion of the light guide plate extends on the switch substrate. The method of claim 55, An edge portion of the light guide plate extends on the switch substrate. In the keypad lighting device, A light guide plate through which light propagates therein; A plurality of reflection patterns formed locally on the light guide plate and reflecting a part of the light propagating into the light guide plate to be emitted to the outside of the light guide plate; At least one light emitting element disposed to face a side surface of the light guide plate, and configured to couple light into the light guide plate; It includes a switch substrate having at least one switch formed on the upper surface facing the light guide plate, An edge portion of the light guide plate extends on the switch substrate. Claim 66 was abandoned when the setup fee was paid. 66. The method of claim 65, The light guide plate has a self-healing force, and the keypad lighting device, characterized in that restored to the circular shape after deformation. 66. The method of claim 65, The light guide plate is a device for keypad lighting, characterized in that the transparent rubber material. The method of claim 67, Keypad lighting device, characterized in that the material of the light guide plate is polyurethane or silicon. 66. The method of claim 65, Keypad lighting device, characterized in that the material of the light guide plate is polycarbonate or acrylic resin. 66. The method of claim 65, And the reflective pattern causes diffuse reflection. 66. The method of claim 65, And the reflective pattern is formed on an upper surface or a lower surface of the light guide plate. The method of claim 65, wherein the switch substrate, A printed circuit board having a plurality of conductive contact members formed on an upper surface thereof; And a dome sheet attached to an upper surface of the printed circuit board and having a plurality of conductive domes. Claim 73 was abandoned upon payment of a set-up fee. The method of claim 72, The light emitting device is a keypad lighting apparatus, characterized in that installed on one side of the printed circuit board. 66. The method of claim 65, Keypad illumination device, characterized in that the density or size of the reflective pattern is changed in order to uniformly adjust the overall light quantity distribution emitted to the outside of the light guide plate.

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