JP2006033203A - Mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal with enhanced reliability of waterproof performance. <P>SOLUTION: In the mobile terminal, a key unit 8 including a key board 6 formed resulting from laminating a spacer sheet 3, an upper electrode sheet 4, and a dome sheet 5, and a key top unit 7 laminated on the key board 6 is provided onto a printed circuit board 2 formed with a lower electrode 1, and the key unit 8 is fixed in a key unit container recessed part 10 formed on the surface of a front case 9, and a waterproof sheet 11 is interposed between the key board 6 and the key top unit 7, the waterproof sheet 11 being a thin membrane the four-circumferential rear side of which is adhered to a bottom wall of the key unit container recessed part 10 wherein the adhered boundary face is used for the waterproof sealing face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a portable terminal device.

As a portable terminal device with improved waterproof performance of the key input unit, one described in Patent Document 1 is known. In this conventional example, the key top unit is formed by laminating a drip-proof sheet on a key substrate having upper and lower electrodes sandwiching a spacer sheet and a dome sheet. Ribs are formed on the periphery of the surface of the drip-proof sheet. Sealing for waterproofing is performed by sandwiching the key top unit between the ribs and the back of the case.
Japanese Utility Model Publication No. 6-28952

  However, the sealing in the conventional example described above is achieved by causing the ribs of the drip-proof sheet to function as packings, but variations in the bending allowance of the ribs occur due to accumulation of case or rib manufacturing errors. It is inevitable.

As a result, there is a drawback in that the bending allowance of the rib becomes too small and the desired sealing performance may not be exhibited, resulting in lack of reliability.
The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide a portable terminal device with improved waterproof performance.

  The key operation surface of the portable information terminal device is formed by holding the key unit 8 in the key unit housing recess 10 formed in the front case 9. The key unit 8 includes a key substrate 6 and a key top unit 7 stacked on the key substrate 6. In order to prevent water from entering the electrodes and the like of the key substrate 6, A waterproof sheet 11 is interposed between the key top unit 7 and the key top unit 7.

  The waterproof sheet 11 is formed in a thin film shape so that the operation force to the key top unit 7 can be efficiently transmitted to the key substrate 6, and the four back surfaces are joined to the bottom wall portion of the key unit housing recess 10. By adhering the waterproof sheet 11 formed in a thin film to the front case 9 on the back surface, the sealing surface can be reliably secured, and the reliability of the sealing is improved.

  For joining the waterproof sheet 11 to the front case 9, an adhesive tape that has been attached in advance to the back surface of the waterproof sheet 11 can be used.

  According to the present invention, the reliability of waterproof performance can be increased.

  FIG. 1 shows an embodiment of the present invention configured as a mobile phone. The mobile phone is formed by connecting the movable side body 18 to the fixed side body 17 so as to be foldable. The movable body 18 is equipped with an antenna 18a, and a liquid crystal display unit 18b and a speaker 18c are arranged at positions that appear in the front in the usage posture shown in FIG.

  On the other hand, in the use posture, the fixed-side main body 17 in which the key operation surface with a plurality of key tops 19, 19,. The control board 21 is accommodated and formed in the case body to be formed. Appropriate packing (not shown) is interposed at the connection interface between the rear case 20 and the front case 9 in order to prevent water or the like from entering the case body. An attachment boss 20 a for fixing the control board 21 is erected on the bottom wall of the rear case 20.

  The key operation surface is formed by arranging the key unit 8 on the surface of the front case 9. As shown in FIG. 3, the key unit 8 includes a key substrate 6 and a key top unit 7 disposed on the key substrate 6, and a waterproof sheet 11 is provided between the key substrate 6 and the key top unit 7. Is installed. As shown in FIG. 3B, the key substrate 6 has a gap formed between the lower electrode 1 formed on the flexible printed circuit board 2 and the upper electrode 4a on the upper electrode sheet 4 by the spacer sheet 3. The dome sheet 5 is placed on the upper electrode sheet 4 for the purpose of imparting a moderation feeling during operation. On the flexible printed board 2, an LED (small lighting device 12) used as a light source for illuminating a key top 19 to be described later is mounted, and a wiring portion (cable 14) is formed at one end.

  On the other hand, the key top unit 7 is formed by forming a plurality of key tops 19, 19... On the same sheet, and a predetermined number or the like is displayed on the key top 19. The key top unit 7 is arranged with the key top 19 exposed to the outside from the opening 16a of the key cover 16, and when a predetermined key top 19 is pressed, the upper and lower electrodes 4a and 1 come into contact with each other to press the key. Detected.

  The waterproof sheet 11 is a sheet made of a flexible synthetic resin that does not transmit water. In this embodiment, a PET resin having a thickness of about 0.08 (mm) is used. Further, the waterproof sheet 11 is formed to be transparent in order to effectively transmit the irradiation light from the LED 12 on the flexible printed circuit board 2 to the key top.

  The front case 9 that houses the key unit 8 configured as described above further includes a key unit housing recess 10 that fits and houses components above the waterproof sheet 11 and a central portion of the key unit housing recess 10. A key board housing recess 13 is formed which is formed to be depressed and accommodates a key board 6 smaller than the key unit 8 and the waterproof sheet 11. The key board housing recess 13 has a depth dimension substantially equal to the height of the key board 6, and an insertion hole 15 for inserting the wiring part 14 of the key board 6 is opened at a predetermined location.

  In assembling these parts, first, the key board 6 is fitted into the key board housing recess 13 and fixed. The key board 6 is fixed by inserting the wiring part 14 through the insertion hole 15 and connecting it to the connector 21a on the control board 21, and then bonding the back surface of the flexible printed board 2 to the bottom wall of the key board housing recess 13. Is called. By bonding the key board 6 using an adhesive, the contact hole between the insertion hole 15 and the key board 6 and the front case 9 is completely sealed. Intrusion is completely prevented.

  Next, the waterproof sheet 11 is fixed on the key substrate 6. The waterproof sheet 11 can be fixed by an adhesive, but the influence of the flow of the adhesive on the movable part of the key board 6 is avoided, and the possibility of bonding the waterproof sheet 11 by the adhesive is taken into consideration. It is desirable to use an adhesive. Fixing with an adhesive is performed by sticking an adhesive sheet in advance to the waterproof sheet 11 or the front case 9 side.

  The waterproof sheet 11 is fixed to the bottom wall of the key unit housing recess 10 disposed so as to surround the key board housing recess 13, and the waterproof sheet 11 with the four-sided back surface fixed is used only when it is fixed. The operability to the key top is not adversely affected by its flexibility.

  When the waterproof sheet 11 is fixed as described above, waterproof sealing with respect to the key substrate 6 is secured, and a short circuit between the upper and lower electrodes 4a and 1 is prevented. In addition, since the waterproof sheet 11 is adhered to the four-sided back surface in a spread state, the sealing sheet is highly reliable in spite of being thin.

  The key top unit 7 is placed on the waterproof sheet 11 and fixed by the key cover 16. As described above, the key cover 16 is provided with a plurality of openings 16 a through which the key tops are inserted, corresponding to the key tops 19. As shown in FIG. 2, the key cover 16 is provided with a hanging wall 16d that hangs down from the side edge. To regulate.

  Further, a locking leg 16b is formed on the hanging wall 16d. The locking leg 16b is provided with a locking portion 16c, and the key cover 16 is detachable by locking the locking portion 16c to the locked portion 10a formed on the side wall of the key unit housing recess 10. Installed. By attaching the key cover 16 in a locked state and making it detachable from the front case 9, the user can remove the sand by removing the key cover 16 when sand or the like is mixed in. In addition, since the internal airtightness is ensured by the waterproof sheet 11 and the key substrate 6, it does not cause a functional failure.

1 is a perspective view showing a mobile phone to which the present invention is applied. It is a disassembled perspective view which shows the principal part of this invention. It is a figure which shows a key board | substrate, (a) is an exploded sectional view, (b) is sectional drawing of an assembly state. It is sectional drawing of a stationary-side main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower electrode 2 Printed circuit board 3 Spacer sheet 4 Upper electrode sheet 5 Dome sheet 6 Key board 7 Key top unit 8 Key unit 9 Front case 10 Key unit accommodation recessed part 11 Waterproof sheet 12 Small lighting device 13 Key board accommodation recessed part 14 Cable 15 Insertion Hole 16 Key cover

Claims (5)

A key unit having a key board in which a spacer sheet, an upper electrode sheet, and a dome sheet are laminated on a printed board on which a lower electrode is formed, and a key top unit laminated on the key board;
A portable information terminal device in which a key unit is fixed in a key unit housing recess formed on the front case surface,
A portable information terminal device is provided between the key substrate and the key top unit, with a thin-film waterproof sheet having a four-sided back surface bonded to the bottom wall of the key unit housing recess and having the adhesive interface as a waterproof sealing surface. On the printed circuit board, a small lighting device is mounted,
The portable information terminal device according to claim 1, wherein the waterproof sheet is formed of a translucent material. 3. The portable information terminal device according to claim 1, wherein the key substrate is accommodated in a key substrate accommodating recess formed in a central portion of the key unit accommodating recess. The key board is fixed to the bottom wall surface of the key board housing recess by an adhesive layer whose back four sides also serve as waterproof sealing,
4. The portable information terminal device according to claim 3, wherein an insertion hole for a cable introduced from the key board into the case internal space is opened in the key board housing recess. 5. The portable information terminal device according to claim 1, wherein the key top unit is pressed by a key cover that can be attached to and detached from the key unit housing recess to prevent the key top unit from falling off the front case.

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