JP2012069317A - Key unit and electronic apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a key unit and an electronic apparatus having the same capable of illuminating a display part of a key top more uniformly even if a light guide with a pusher is used.SOLUTION: A key unit 2 including a key sheet 10 connecting one or two or more key tops or two or more key tops 20 and at least a translucent light guide 60 disposed on the rear side of a key top or the key sheet 10 comprises: a pedestal 62 which is provided with a translucent display part 21 on the key top 20 and protrudes from the surface of a sheet 61 to the light guide 60; a pusher 63 which further protrudes from the pedestal 62; and a reflective layer which is formed on at least the front or rear side of the light guide 60 and reflects the light propagating inside the light guide 60 onto the display part 21. The pedestal 62 is provided with a level difference 62a with the surface of the sheet 61 of the light guide 60 outside the display part 21 in a planar view of the display unit 21.

Description

  The present invention relates to a key unit including at least a key sheet in which a key top or two or more key tops are connected, and a translucent light guide disposed on the back side thereof, and an electronic apparatus including the key unit. is there.

  In recent years, in electronic devices such as mobile phone devices, personal digital assistants (PDAs), audio devices, etc., a predetermined part of the key top provided on the operation surface is illuminated by an LED or the like incorporated therein, so that it can be easily operated in a dark place. More and more devices are available.

  As a method of illuminating the key top that constitutes the operation surface or the key sheet in which two or more key tops are connected, for example, a transparent film made of PET or urethane is used as a light guide, and the key top or key sheet is placed in the surface direction. A method is known in which LED, etc., is guided from the side of the light guide and reflected from the reflective layer formed on the back side of the key top in the light guide to be emitted from the extracted portion of the key top. It has been. In the case of such an illuminated key unit, the light guide needs to function as a pressure transmission medium that transmits a pressure from each key top to a switch disposed on the back side of the light guide. For this reason, usually, a pusher (presser) is arranged in each key top back direction (either switch side or key top side) on the sheet surface of the light guide (see, for example, Patent Document 1 and Patent Document 2). ).

JP 2008-130506 A JP 2008-300153 A

  However, the above prior art has the following problems. When the pusher is formed on the light guide, the light guided inside the light guide is reflected by the side surface of the pusher. Light reflected from the side surface of the pusher (referred to as edge light) becomes a cause of luminance unevenness in the display part of the key top.

  The present invention has been made to solve the above-described problem, and includes a key unit that can illuminate the display portion of the key top more uniformly even when a light guide having a pusher is used. An object is to provide electronic equipment.

  In one embodiment of the present invention for solving the above-described object, one or two or more key tops, or a key sheet connecting two or more key tops, and a translucent material disposed on the back side of the key top or key sheet are provided. A key unit comprising at least a light guide, the key top having a light-transmitting display, the light guide being disposed in the back direction of the key top and protruding from the seat surface of the light guide, and the pedestal Furthermore, a pusher that protrudes and a reflection layer that is formed on at least one of the front side and the back side of the light guide and reflects light propagating through the light guide toward the display unit are provided. This is a key unit having a step with the sheet surface of the light guide on the outside in a plan view.

  Another aspect of the present invention is a key unit in which the light guide is arranged on the back side of the key top or the key sheet so that at least one of the pushers protrudes toward the key top.

  Another form of the present invention is a key unit in which a pedestal is formed so as to be inclined from the seat surface of the light guide toward the pusher.

  Another embodiment of the present invention is a key unit in which the light guide is made of any one of a thermosetting urethane resin, an ultraviolet curable resin, and an electron beam curable resin.

  In another embodiment of the present invention, the reflective layer is formed of a plurality of recesses recessed inward of the light guide, and the integration density or depth of the recesses is different among the plurality of reflection layers. Is a unit.

  One embodiment of the present invention is an electronic device including any one of the above key units.

  ADVANTAGE OF THE INVENTION According to this invention, when using the light guide which has a pusher, the display part of a keytop can be illuminated more uniformly.

FIG. 1 is a perspective view of an electronic apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view of a key unit provided in the electronic apparatus shown in FIG. FIG. 3 is a cross-sectional view of the key unit shown in FIG. FIG. 4 is an enlarged sectional view showing the light guide shown in FIG. 3 in an enlarged manner. FIG. 5 is a plan view of the key sheet and the light guide shown in FIG. FIG. 6 is a plan view showing a state in which a key sheet is overlaid on the front side of the light guide shown in FIG. FIG. 7 is a plan view showing a situation when illuminated from the back side of the key sheet of the key unit shown in FIG. FIG. 8 is a cross-sectional view similar to FIG. 3 of the key unit provided in the electronic apparatus according to the second embodiment of the present invention. FIG. 9 is an enlarged sectional view showing the light guide shown in FIG. 8 in an enlarged manner. FIG. 10 is a cross-sectional view similar to FIG. 3 of the key unit provided in the electronic apparatus according to the third embodiment of the present invention.

  Next, each embodiment of the key unit according to the present invention and an electronic apparatus including the key unit will be described.

<First embodiment>

  FIG. 1 is a perspective view of an electronic apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view of a key unit provided in the electronic apparatus shown in FIG.

  A cellular phone device 1 which is an example of an electronic device according to the first embodiment has a foldable configuration that can be opened and closed, and includes a key unit 2 on one side of an opened surface. As shown in FIG. 2, the key unit 2 includes a plate-like key sheet 10 having a substantially rectangular plane in a plan view on the outermost surface. The key sheet 10 is provided with a total of 19 key tops 20 protruding in the front side on the front side surface in a connected state. In addition, the key sheet 10 has a rectangular frame-shaped multidirectional key 30 that is separated from the key sheet 10 at a substantially upper left and right center in plan view, and a substantially rectangular central key inside the multidirectional key 30. 31. The multi-directional key 30 and the center key 31 have a gap 32 along the outer periphery thereof, and have a structure in which it is difficult to transmit the pressing operation to the key sheet 10 even when they are pressed toward the back side. The key sheet 10 includes a groove 22 that is recessed from the top surface of the key top 20 around the key tops 20. Since the thickness of the back side remaining portion of the groove 22 is very thin, even if each key top 20 is pressed from the front side, it is difficult to transmit the force to the adjacent key top 20. In addition, in the drawings after FIG. 2, there are also diagrams in which only some of the components are denoted by reference numerals when there are many places with the same reference numerals such as the key top 20 and the groove 22. In view of the ease of viewing, the reference numerals are omitted.

  The key sheet 10 is preferably composed of a resin having excellent translucency, such as a polycarbonate (PC) resin, a polyethylene terephthalate (PET) resin, an acrylic resin, and an ultraviolet curable resin (preferably an acrylic urethane resin). The The key sheet 10 includes a light shielding film or a light shielding paint (in this embodiment, representatively “light shielding film”) 50 (see FIG. 3) on the back side. The light-shielding film 50 is preferably composed of a resin having excellent translucency similar to that of the key sheet 10, but is not limited thereto, and is not limited thereto, and is made of a transparent material such as a thermoplastic polyurethane elastomer (TPU) or a thermosetting polyurethane elastomer (TSU). You may comprise from the elastomer which is excellent in both light property and a softness | flexibility. The suitable thickness of the light shielding film 50 is 30-200 micrometers. The light shielding film 50 has a display portion 21 in the shape of a letter, a picture, a symbol or the like for transmitting light from the back side to the front side of the key top 20 at the position of each key top 20. The display unit 21 is a part that is not printed. On the other hand, the region other than the display portion 21 of the light shielding film 50 is printed with a light shielding ink such as black or silver (which may be either pigment-based or dye-based).

  The key sheet 10 including the key top 20 may be formed of aluminum or stainless steel. In that case, it is preferable that the display unit 21 is formed by a through hole penetrating in the front and back direction of the key top 20 and a transparent resin is embedded in the through hole. If the display unit 21 is configured in this manner, light from the back side of the key sheet 10 can be emitted in the front direction only from the region of the display unit 21 without using the light shielding film 50.

  The multidirectional key 30 and the central key 31 may be made of a resin having excellent translucency like the key sheet 10, but in this embodiment, it is necessary to illuminate from the multidirectional key 30 and the central key 31 itself. Since it illuminates from the clearance gap 32 of those outer periphery, it is comprised from the metal. For example, aluminum, stainless steel, or the like can be used as the metal. When the multi-directional key 30 and the center key 31 are formed of the same resin as the key sheet 10, the gap 32 may be integrated with the key sheet 10 with a thin groove.

  An LED 40 that is an example of a light source is disposed on a switch board (described later) disposed in the back direction of the key sheet 10. The LED 40 is used for irradiating light into the light guide from the side surface of the light guide (described later) and illuminating the display unit 21 of the key top 20. Although two LEDs 40 are displayed in FIG. 2, one or three or more LEDs 40 may be arranged. Furthermore, a light source other than the LED 40 may be used.

  FIG. 3 is a cross-sectional view of the key unit shown in FIG. FIG. 4 is an enlarged sectional view showing the light guide shown in FIG. 3 in an enlarged manner.

  As shown in FIG. 3, the key unit 2 has a configuration in which the key sheet 10, the light shielding film 50, the light guide 60, and the switch substrate 70 are sequentially stacked from the front side. The light guide 60 is made of a resin excellent in both translucency and flexibility, preferably a thermosetting urethane resin, an ultraviolet curable resin, or an electron beam curable resin. As the ultraviolet curable resin or the electron beam curable resin, for example, urethane resin, acrylic resin, epoxy resin, silicone resin, polyimide resin, or a composite resin of two or more thereof can be used. By forming the light guide 60 from a thermosetting urethane resin, an ultraviolet curable resin, or an electron beam curable resin, the light guide 60 can be easily made thinner, and unlike the PC resin, a reflection layer described later is formed by laser processing. Even so, it is hard to discolor. The light guide 60 is preferably composed of a single material (a single type of material may be a polymer alloy). In addition to the resin, for example, glass can be used as the material of the light guide 60.

  The light guide 60 has a region protruding in two stages at a position on the back side of the key top 20 on the front side surface of the plate-like sheet 61 (that is, the surface on the key sheet 10 side). The two-stage projecting regions each include a pedestal 62 projecting from the seat 61 and a pusher 63 further projecting from substantially the center in plan view of the pedestal 62. The pedestal 62 has a step 62 a between the seat 61.

  The height (H1) of the pusher 63 is preferably in the range of 0.02 to 0.1 mm (20 to 100 μm), more preferably in the range of 0.04 to 0.06 mm (40 to 60 μm). The height (H2) of the step 62a of the pedestal 62 is preferably in the range of 0.01 to 0.15 mm (10 to 150 μm), more preferably in the range of 0.05 to 0.10 mm (50 to 100 μm). . The height (H3) from the top surface of the pusher 63 to the front surface of the sheet 61 is preferably in the range of 0.03 to 0.40 mm (30 to 400 μm), more preferably 0.15 to 0.25 mm ( 150 to 250 μm). The thickness (H4) of the sheet 61 is preferably in the range of 0.08 to 0.20 mm (80 to 200 μm), more preferably 0.10 to 0.16 mm (100 to 160 μm). The outer diameter (D) of the pusher 63 is preferably 1.5 mm or less, more preferably 1.0 mm or less. Further, the pedestal 62 may be horizontal, but it is preferable to incline downward from the boundary with the pusher 63 toward the step 62a, and in particular, an angle (inclination angle) formed with the front side surface of the seat 61 is 5 degrees. The following is preferable. Thus, by tilting the pedestal 62, the edge light of the pusher 63 can be further reduced.

  On the other hand, the sheet 61 of the light guide 60 includes a plurality of recesses 64a that are recessed inwardly at positions on the back side of the key tops 20 on the back side surface (that is, the surface on the switch board 70 side). The concave portion 64a functions as a reflective layer 64 that reflects light transmitted through the light guide 60 and refracts it toward the key top 20 side. It is preferable that the back side surface and the front side surface of the light guide 60 other than the reflective layer (region where the concave portions 64a are integrated) 64 have a mirror surface with an average surface roughness (Ra) of 1.5 μm or less. The mirror surface can be realized by mirror-finishing the inner surface of a mold used when the light guide 60 is molded, or by mirror polishing after the light guide 60 is molded. Is preferred. Further, the plastic film surface molded on the mirror surface may be transferred at the time of molding.

  The recess 64a is preferably formed by laser processing (for example, processing using a carbon dioxide laser). The recess 64a is preferably formed with a depth of 0.03 to 0.07 mm (30 to 70 μm) and an opening diameter of 0.1 to 0.3 mm. Usually, the longer the distance from the LED 40, the smaller the amount of light. Therefore, in order to uniformly illuminate the plurality of display units 21, it is necessary to increase the reflectance toward the back side of the key top 20 farther from the LED 40. For this reason, it is preferable that the recesses 64a be formed at a high density or a depth as the distance from the LED 40 increases.

  The switch board 70 includes a dome switch 71 as an example of a switch at a position on the back side of the key top 20. The switch substrate 70 is preferably a glass epoxy substrate in which a cloth knitted with glass fibers is impregnated with an epoxy resin. However, as the switch substrate 70, a glass composite substrate, a ceramic substrate made of alumina or the like may be used. The dome switch 71 has a structure in which the dome is crushed by receiving a pressure from the key top 20 through the light guide 60, and the switch is turned on at that time. A metal dome is preferably used as the dome. The switch board 70 includes a dome covering sheet 72 so as to cover the dome switch 71.

  FIG. 5 is a plan view of the key sheet and the light guide shown in FIG. FIG. 6 is a plan view showing a state in which a key sheet is overlaid on the front side of the light guide shown in FIG.

  As shown in FIG. 5, the light guide 60 has a pedestal 62 at a position behind the other key tops 20 except for the multidirectional key 30 and the center key 31. The pushers 63 are respectively formed on the back side of the multi-directional key 30 in four directions, up and down, left and right, on the back side of the central key 31, and on the back side of each key top 20. The side surface of the pusher 63 is a portion that easily reflects light propagating through the light guide 60. For this reason, the display unit 21 of the key top 20 is affected by the edge light that shines on the side surface of the pusher 63, thereby causing uneven brightness depending on the location of the display unit 21, or uneven brightness within one display unit 21. Prone to occur. In order to prevent this, the height of the pusher 63 arranged at the position on the back side of each key top 20 is formed as low as possible, and the pedestal 62 is formed immediately below. The step 62a of the pedestal 62 can also cause edge light, but the step 62a is formed in the light guide 60 so as to be outside the display unit 21 in plan view. For this reason, even if an edge light occurs at the step 62a, the luminance of the display unit 21 is hardly affected. In this embodiment, all the pedestals 62 have substantially the same area in plan view, and the level difference 62a of any pedestal 62 is outside in the plan view of the display unit 21 of each key top 20. The size is determined. However, you may change according to the magnitude | size of each display part 21, without making the magnitude | size of the base 62 substantially the same.

  On the other hand, since the multi-directional key 30 and the center key 31 do not include the display unit 21, no problem occurs even if an edge light is generated on the side surface of the pusher 63. For this reason, in this embodiment, only the pusher 63 is formed on the back side of the multidirectional key 30 and the central key 31 without forming the pedestal 62. However, when the multi-directional key 30 or the central key 31 is provided with the display unit 21, the pedestal 62 is formed so that the step 62 a comes outside the display unit 21, as with each key top 20. It is preferable to form a pusher 63 near the top.

  In this embodiment, the reflective layer 64 in which the concave portions 64 a are integrated is formed with an area equal to or larger than each top surface of the key top 20 or the multidirectional key 30. However, the reflective layer 64 may be in any form that reliably surrounds the gap 32 on the outer periphery of the display section 21 of the key top 20 or the multidirectional key 30. In this embodiment, the pedestal 62 is formed so that the step 62a is disposed on the inner side or the same as the reflective layer 64 in a plan view. However, the pedestal 62 may be formed such that the step 62 a is outside the reflective layer 64.

  FIG. 7 is a plan view showing a situation when illuminated from the back side of the key sheet of the key unit shown in FIG. A black portion indicates a light shielding region, and a white portion indicates an illumination region.

  As shown in FIG. 7, the illumination area is the gap 32 on the outer periphery of both the multidirectional key 30 and the center key 31 and the display unit 21 in the area of each key top 20. Since the height of the pusher 63 is suppressed and the edge light generated on the side surface is reduced, and the step 62a exists outside the display unit 21 in a plan view, luminance unevenness among the plurality of display units 21 or Luminance unevenness in one display unit 21 hardly occurs.

<Second Embodiment>

  Unlike those according to the first embodiment, the electronic device according to the second embodiment and the key unit included therein are provided with a reflective layer including a plurality of recesses on the key sheet side surface of the light guide in the key unit. Prepare. Other configurations are the same as those in the first embodiment described above. Therefore, the same reference numerals are given to the common components, and the duplicate description of the common components is omitted.

  FIG. 8 is a cross-sectional view similar to FIG. 3 of the key unit provided in the electronic apparatus according to the second embodiment of the present invention. FIG. 9 is an enlarged sectional view showing the light guide shown in FIG. 8 in an enlarged manner.

  As shown in FIGS. 8 and 9, the light guide 60 constituting the key unit 2 according to the second embodiment has a reflective layer 64 formed of a plurality of recesses 64a on the surface on the pusher 63 and pedestal 62 side. Prepare. The region where the recess 64a is formed is a region surrounding the outside of the display unit 21 of each key top 20 in plan view. Further, the pedestal 62 is formed so that a step 62a on the outer periphery thereof exists outside the display unit 21 in a plan view. The recess 64 a is formed on the top surface of the pedestal 62 and also on the top surface of the pusher 63, but may not be formed on the top surface of the pusher 63.

<Third embodiment>

  The electronic device according to the third embodiment and the key unit provided therein are different from those according to the first embodiment. In the key unit, the light guide is arranged so that the pusher faces the dome switch side. . Other configurations are the same as those in the first embodiment described above. Therefore, the same reference numerals are given to the common components, and the duplicate description of the common components is omitted.

  FIG. 10 is a cross-sectional view similar to FIG. 3 of the key unit provided in the electronic apparatus according to the third embodiment of the present invention.

  As shown in FIG. 10, even if the light guide 60 is arranged so that the pusher 63 faces the dome switch 71 side, as in the first embodiment, the luminance unevenness between the display units 21 and 21 or one light guide 60 Luminance unevenness in the display unit 21 can be reduced.

<Example of key unit production>
A UV acrylic resin (part number: SP-17, manufactured by Dainichi Seika Kogyo Co., Ltd.) is injected into a mold having a recess capable of forming the pusher 63, the pedestal 62 and the sheet 61 (mold having a chrome plating on the surface). The surplus is scraped out with a scrubber, and a predetermined amount of UV acrylic resin is filled in the mold. Next, a 0.125 mm thick PET film (product number: S-10, manufactured by Toray Industries, Inc.) is laminated on the surface of the UV acrylic resin and put into a UV irradiation apparatus, and then the integrated light quantity becomes 500 mJ / m ² . Under conditions, UV is irradiated from the PET film side to cure the UV acrylic resin in the mold. Next, after peeling off the PET film from the UV acrylic resin cured body, the cured body is released from the mold to obtain a light guide 60 made of only the UV acrylic resin. The light guide 60 includes a plurality of pedestals 62 having a step 62a of 0.01 mm on a sheet 61 having a thickness of 0.13 mm, and an outer diameter of 1.2 mm and a height of 0.05 mm at substantially the center in the surface of each pedestal 62. The cylindrical pusher 63 is provided. The pedestal 62 is inclined downward from the base of the pusher 63 toward the step 62a, and the drop is 0.05 mm. The region surrounded by the step 62a of the pedestal 62 is formed to have a common size and a size that is outside in a plan view of all the display units 21 described later. Further, both the front side and the back side of the light guide 60 are mirror-finished with an average surface roughness (Ra) of 1.5 μm.

  Next, a plurality of recesses are formed on the surface of the light guide 60 on the pusher 63 side in a region having the same area as the top surface of the key top 20 at a position behind the key top 20 by laser processing using a carbon dioxide laser. A reflective layer 64 made of 64a is formed. Each of the reflective layers 64 located farther from the LED 40 has a narrower interval (pitch) between the concave portions 64a and a larger diameter of the concave portions 64a to increase the reflectance even with a small amount of light. The difference in luminance between the display units 21 is reduced. Specifically, the pitch is changed in the range of 0.5 to 1.0 mm, and the diameter of the recess 64a is changed in the range of 0.1 to 0.3 mm.

  Next, the light guide 60 is disposed on the switch substrate 70 so that the pusher 63 is disposed immediately above the plurality of dome switches 71 covered with the dome covering sheet 72. As shown in FIG. 2, the switch board 70 includes LEDs 40 at two locations. Subsequently, the PC key sheet 10 having a shape in which a plurality of key tops 20 are connected, the aluminum multi-directional key 30 and the aluminum central key 31 are light-shielded and printed with light-shielding ink except for the display unit 21. The key sheet 10, the multidirectional key 30, and the center key 31 are set with the light shielding film 50 facing the light guide 60. The key unit 2 is completed through the above steps.

  When the LED 40 is turned on, the key unit 2 having such a configuration has almost no luminance unevenness in each display portion 21 of each key top 20 and no luminance unevenness in one display portion 21.

<Other embodiments>

  As mentioned above, although each embodiment of the key unit of this invention and an electronic device provided with it has been demonstrated, this invention is not limited to each above-mentioned embodiment, It can implement with various deformation | transformation. . For example, instead of the key sheet 10 having a plurality of key tops 20 connected to the front side of the light guide 60, a plurality of individually independent key tops 20 may be arranged. Moreover, in order to make the brightness | luminance between the display parts 21 and 21 different, you may change the density, depth, etc. of the several recessed part 64a arrange | positioned at the back side of each display part 21. FIG.

  Further, in one light guide 60, a part of the plurality of pushers 63 may be formed on the key top 20 side, and the other pushers 63 may be formed on the dome switch 71 side. In this case, all of the plurality of recesses 64a may be formed on the surface on the key top 20 side or on the surface on the dome switch 71 side. Further, in order to provide the key top 20 with the translucent display portion 21, a light shielding film 50 may be disposed on the front surface of the key top 20 or light shielding printing may be performed.

  The present invention can be used for an electronic device incorporating a key unit including at least a light guide.

1 Mobile phone equipment (electronic equipment)
2 Key unit 10 Key sheet 20 Key top 21 Display section 60 Light guide 61 Sheet 62 Base 62a Step 63 Pusher 64 Reflective layer 64a Recess

Claims (6)

One or more key tops, or a key sheet connecting two or more of the key tops;
A translucent light guide disposed on the back side of the key top or the key sheet;
A key unit comprising at least
The key top includes a translucent display unit,
The light guide is
A pedestal arranged in the back direction of the key top and protruding from the seat surface of the light guide;
A pusher that protrudes further from the base,
A reflective layer that is formed on at least one surface of the front side or the back side of the light guide and reflects light propagating through the light guide toward the display unit;
With
The key unit, wherein the pedestal includes a step with the seat surface of the light guide on an outer side in a plan view of the display unit.   The key unit according to claim 1, wherein the light guide is disposed on a back side of the key top or the key sheet so that at least one of the pushers protrudes toward the key top.   The key unit according to claim 1, wherein the pedestal is inclined from the seat surface of the light guide toward the pusher.   The said light guide is comprised by any one of a thermosetting urethane resin, an ultraviolet curable resin, or an electron beam curable resin, The Claim 1 characterized by the above-mentioned. Key unit. The reflective layer is formed by a plurality of recesses recessed inward of the light guide,
5. The key unit according to claim 1, wherein the integration density or depth of the recesses is different among the plurality of reflection layers. 6.   An electronic apparatus comprising the key unit according to any one of claims 1 to 5.

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