JP2006101333A - Folding type portable information terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin folding type portable information terminal with a simple structure capable of efficiently utilizing a light supplied from a light source and capable of optimization of a light quantity to be supplied to a liquid crystal display panel by enabling lighting control of the light source. <P>SOLUTION: The folding type portable information terminal is provided with a display unit case having a light guiding plate 11 for guiding a light from a light source 14 provided on a side wall surface to both front and rear surfaces, a first liquid crystal display panel 15 for transmitting a light when a voltage is not applied, a second liquid crystal display panel 30 smaller than the first panel, and a control means 47 for controlling to light the light source 14; and an operation control unit case 52 having an operation key 52b, wherein the cases are coupled with each other by a coupling mechanism so that the terminal can be foldable. In this terminal, the operation case has a surface which opposes the first liquid crystal panel and is worked into a mirror surface, a plurality of light-emitting diode elements 13a is used as the light source 14, and the control means 47 causes the plurality of light-emitting diode elements 13a to selectively light to illuminate the liquid crystal panel. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a foldable portable information terminal, and more particularly, to a foldable portable information terminal that effectively uses light from a light source provided on a side wall of a light guide plate and saves power consumed by the light source.

  In recent years, cellular phones, PDAs, or portable information terminals that have a communication function and can display more messages have been commercialized and widely used. Among these terminals, in particular, mobile phones can connect to the Internet and display various functions such as e-mail, information retrieval, or maps, in addition to the telephone function for exchanging original conversations, and destination guidance It is equipped with various functions such as navigation, and more software will be installed in the future, making it indispensable for daily life.

  As such various kinds of software are installed in mobile phones, the phone itself, so-called hardware, is pursued to be more convenient, lighter and more portable, and various types are developed and commercialized. ing.

  This mobile phone type is roughly classified into a bar type and a foldable type. Recently, the liquid crystal display panel is turned upside down so that the other party can be confirmed while folded and the time etc. are displayed. Many of the latter foldable types that have been incorporated into places have become widespread.

  In addition, since this foldable mobile phone is easy to be bulky when folded, it is thinned. As one means of this thinning, light introduced from the side wall surface is guided to both the front and back surfaces. 2. Description of the Related Art A liquid crystal display panel unit that uses an optical plate and has two first and second liquid crystal display panels arranged on the front and back surfaces of the light guide plate and a so-called double-sided light emitting liquid crystal display panel is known. Yes.

  However, this double-sided light emitting type liquid crystal display panel is provided with one light source on the side wall surface of the light guide plate that emits light on both sides, and illuminates the first and second liquid crystal display panels from this light source. When illuminating the first and second liquid crystal display panels with one light source, the amount of light from the light sources is distributed to the first and second liquid crystal display panels at a predetermined ratio, but the balance of the distribution amounts is unbalanced. If this is the case, the light quantity of any of the liquid crystal display panels may be insufficient, and the inconvenience that the contents of the display surface cannot be visually recognized may occur.

  Liquid crystal display devices that have solved such inconvenience are already known and introduced in patent documents (see Patent Documents 1, 2, and 3 below).

  FIG. 7 is a perspective view showing a foldable mobile phone with a liquid crystal display described in Patent Document 1 below.

  The mobile phone 60 includes a display housing 61 having a transmissive liquid crystal display 62 in which liquid crystal is sealed between two transparent plates, and is rotatably connected to the display housing 61 and includes a plurality of switches 64. An operation unit housing 63 provided; an operation for displaying an image on the liquid crystal display 62; and display control means (not shown) for performing inversion control of images displayed on one surface and the other surface of the liquid crystal display. The body 63 has a configuration in which a part of the surface 65 facing the liquid crystal display 62 is formed on the reflective surface.

  According to this configuration, when the display unit housing 62 and the operation unit housing 63 are closed so as to overlap each other, the light transmitted through the liquid crystal display 62 is reflected by the reflecting surface and irradiated toward the liquid crystal display 62, and is folded. Sometimes the shortage of light quantity is compensated for and the display content of the liquid crystal display 62 can be clearly seen.

  Further, the liquid crystal display device described in the following Patent Document 2 is provided with a special reflector to increase the utilization factor of light. FIG. 8 shows a double-sided light emitting liquid crystal display module described in this document. FIG.

  The double-sided light emitting liquid crystal display module 70 includes a double-sided light emitter 71, a first liquid crystal display panel 72 disposed on the one surface 71a side of the light emitter 71, and a second liquid crystal display panel 74 disposed on the other surface 71b. A semi-transmissive reflector 76, which is disposed between the other surface 71b and the second liquid crystal display panel 74, and transmits part of the light emitted from the other surface 71b. While reflecting to the 1st liquid crystal display panel 72 side, it has the function which permeate | transmits the remainder of light to the 2nd liquid crystal display panel 74 side as white light. The first liquid crystal display panel 72 has a configuration in which a liquid crystal layer 73 is formed between a pair of counter substrates 72a and 72b. Similarly, the second liquid crystal display panel 74 is a liquid crystal between a pair of counter substrates 74a and 74b. The layer 75 is formed.

  In such a double-sided light emitting liquid crystal display module 70, if the amount of light on the first liquid crystal display panel 72 side is less than 70%, the display on the first liquid crystal display panel 72 becomes dark, which is not preferable. If the amount of light on the display panel 72 exceeds 90%, the amount of light on the second liquid crystal display panel 74 side becomes relatively small and the display on the second liquid crystal display panel 74 becomes dark. Of the light emitted to the one surface 71a side and the other surface 71b side emits a light amount of 70% to 90% from the one surface 71a side and emits a light amount of 10% to 30% from the 71b side. Has been adjusted. This light amount adjustment is performed by changing the reflectance of the semi-transmissive reflector 73 or making the surface of the double-sided light emitter 71 uneven.

  FIG. 9 is an exploded perspective view showing a double-sided liquid crystal display device mounted on a foldable mobile phone described in Patent Document 3 below. As shown in FIG. 9, the double-sided liquid crystal display device 80 includes an inner liquid crystal display panel 81, that is, a main liquid crystal display panel, a holder 82 that accommodates the main liquid crystal display panel 81, a backlight unit 83, and an outer liquid crystal display. A panel 86, that is, an auxiliary liquid crystal display panel and a frame 87 for fixing the auxiliary liquid crystal display panel 86 are provided. The backlight unit 83 includes a light guide plate 85 and a flexible substrate 84.

  The backlight unit 83 is assembled as follows. First, the light guide plate 85 is inserted inside the holder 82, and the liquid crystal display panel 81 is attached to the bottom surface of the light guide plate 85. A flexible substrate 84 is disposed above the light guide plate 85, and the outer liquid crystal display panel 86 is fixed to the holder 82 by a frame body 87 on the flexible substrate 84. A light source 84 a is fixed to one side surface of the flexible substrate 84.

The light emitting source 84a includes not only LEDs but also fluorescent lights depending on the type of light emitting diode element (hereinafter referred to as LED) that emits light of R (red), G (green), and B (blue) simultaneously. Other light sources such as lamps are used.
JP 2002-320012 A (FIG. 3, paragraphs [0052] to [0053]) JP 2004-144990 A (FIG. 1, paragraphs [0017] to [0023]) JP 2002-287144 A (FIG. 4, paragraphs [0026] to [0027], [0033])

  However, in the mobile phone described in Patent Document 1, since the liquid crystal display is composed of a single liquid crystal display panel, display control means for performing inversion control on images displayed on one surface and the other surface of the liquid crystal display panel. Is necessary and the circuit configuration is complicated.

  Further, the double-sided light emitting liquid crystal module described in Patent Document 2 must use a special transflective reflector, so that the procurement thereof is cumbersome and costly, and the number of parts increases and assembly work is required. Is troublesome.

  The liquid crystal display devices of Patent Documents 2 and 3 each include a main and auxiliary liquid crystal display panel, and the auxiliary liquid crystal display panel is smaller than the main liquid crystal display panel, and these main and auxiliary liquid crystal display panels are used. The liquid crystal display panel is illuminated by one common light source. According to this configuration, by turning on the common light source, the main and auxiliary liquid crystal display panels are illuminated simultaneously, that is, the main liquid crystal display panel is also illuminated simultaneously with the illumination of the auxiliary liquid crystal display panel.

  However, since the auxiliary liquid crystal display panel is usually smaller than the main liquid crystal display panel, the auxiliary liquid crystal display panel does not require a light amount to illuminate the main liquid crystal display panel. However, since the backlight light source of the liquid crystal display device of the prior art illuminates the main liquid crystal display panel simultaneously with the illumination of the auxiliary liquid crystal display panel, when the common light source is turned on every time the auxiliary liquid crystal display panel is illuminated, As a result, the power consumption of the light source, for example, the capacity of the battery is expedited.

  In addition, this type of liquid crystal display panel is widely used in mobile phones, and since this phone has become multifunctional and a high-capacity power supply is indispensable, power saving is an important design matter. It has become. On the other hand, the foldable mobile phone is thinned so as not to be bulky when folded, and the double-sided light-emitting liquid crystal display panel as described above is adopted as one means of thinning. .

  However, this double-sided light emitting liquid crystal display panel has a structure in which the main and auxiliary liquid crystal display panels are arranged on both sides of the double-sided light emitter, that is, the light guide plate, and are supported by the light guide plate. Since a certain level of mechanical strength must be maintained, the light guide plate cannot be made thin. As a result, it is difficult to reduce the thickness of the liquid crystal display device.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to enable effective use of light supplied from a light source with a simple structure and to control lighting of the light source. An object of the present invention is to provide a thin foldable portable information terminal capable of optimizing the amount of light supplied to the liquid crystal display panel.

  In order to achieve the above object, a foldable portable information terminal according to claim 1 of the present invention includes a light guide plate that guides light introduced from a light source provided on a side wall surface to both front and back surfaces, and the light guide plate. A first liquid crystal display panel that transmits light when no voltage is applied between the first liquid crystal display panel, a second liquid crystal display panel that is smaller than the first liquid crystal display panel, and a control unit that controls lighting of the light source And a display unit housing having an operation key, and the display unit housing and the operation unit housing are coupled by a coupling mechanism so that the display unit housing can be folded. In the foldable portable information terminal in which the key and the first liquid crystal display panel are opposed to each other, the operation unit casing has a mirror-finished surface facing the first liquid crystal display panel and a plurality of the light sources. Light emitting diode element And use, the plurality of light emitting diodes the first selectively turns on the device, and performs illumination of the second liquid crystal display panel by said control means.

  The invention according to claim 2 relates to the foldable portable information terminal according to claim 1, wherein the control means sets the plurality of light emitting diode elements when the first liquid crystal display panel is used. It is characterized in that all the light emitting diode elements are controlled to light up when all the light emitting diode elements are used when the second liquid crystal display panel is used.

  The invention according to claim 3 relates to the foldable portable information terminal according to claim 1, wherein a surface of the light guide plate provided in the display housing on which the second liquid crystal display panel is placed is provided. A thin plate-like reinforcing frame is provided so as to surround the second display panel, and the reinforcing frame is mirror-finished on the surface in contact with the light guide plate.

  According to a fourth aspect of the present invention, there is provided the foldable portable information terminal according to the first aspect, wherein the mirror finish of the operation unit casing is also applied to the surface of the operation key. To do.

  The invention according to claim 5 relates to the foldable portable information terminal according to claim 1, wherein the light guide plate has a reflection layer formed on an outer peripheral side wall surface excluding a side wall surface into which light is introduced. It is characterized by that.

 The present invention can obtain the following effects by providing the above configuration. That is, according to the first aspect of the present invention, the operation unit casing is mirror-finished on the casing surface facing the first liquid crystal display panel, and the first liquid crystal display panel is formed by the transmissive liquid crystal display panel. In addition, since the light emitting diode is controlled to be turned on by the control means for controlling the light source, the light amount can be adjusted according to the liquid crystal display panel to be used, and a power saving effect can be obtained.

That is, for example, when the portable information terminal is a foldable mobile phone, the first and second liquid crystal display panels are usually opposed to the main and sub liquid crystal display panels, that is, the operation keys when folded. Since it is used as a main liquid crystal display panel (first liquid crystal display panel) that displays its contents in conjunction with each other and a sub liquid crystal display panel (second liquid crystal display panel) that mainly displays time or incoming calls, it is portable when folded. By using a liquid crystal display panel that transmits light when no voltage is applied to the main liquid crystal display panel facing the operation key of the telephone, the first liquid crystal display panel can be used when no voltage is applied to the liquid crystal display panel. Can transmit light. Therefore, when the cellular phone is folded, if it is controlled not to apply a voltage to the main liquid crystal display panel, it is irradiated from the light source provided on the side wall surface of the light guide plate, and the mirror finish of the operation housing is applied. The light reflected by the surface passes through the main liquid crystal display panel and irradiates the sub liquid crystal display panel. As a result, the luminance deficiency of the sub liquid crystal display panel is resolved, and the content displayed on the display screen can be clearly seen.

  According to the second aspect of the present invention, the second liquid crystal display panel is smaller than the first liquid crystal display panel. Therefore, when the same amount of light as when the first liquid crystal display panel is illuminated is irradiated, the second liquid crystal display panel is more than necessary. Although the brightness of the liquid crystal display panel increases, the display quality of the liquid crystal display panel is reduced by reducing the number of light sources used by the control means when, for example, the second liquid crystal display panel is used in a folded state. Therefore, it becomes possible to select and control the light source according to the liquid crystal display panel to be used, thereby obtaining the power saving effect of the power supplied to the light source.

  According to the invention described in claim 3, by laminating the first liquid crystal display panel, the light guide plate, and the second liquid crystal display panel by interposing a thin plate-like reinforcing frame around the light guide plate and the second liquid crystal display panel. Even if the first and second liquid crystal display panels and the light guide plate are made thin, they can be supported while being mechanically reinforced with this reinforcing frame. Therefore, even if a reinforcing frame is added, the light guide plate and the first and second liquid crystal plates can be supported. The thickness of the display panel can be reduced, and the liquid crystal display device can be thinned as a whole.

  In addition, since the reinforcing frame is mirror-finished on the surface in contact with the light guide plate, the first liquid crystal display panel can be irradiated with the light reflected on this surface, and the supplied light can be used effectively. The brightness of the first liquid crystal display panel can be improved.

  According to the fourth aspect of the present invention, the surface of the operation key is also mirror-finished, so that the reflection surface is enlarged and the display surface of the second liquid crystal display panel can be brightened.

  According to the fifth aspect of the present invention, since the light guide plate has the reflection layer formed on the outer peripheral side wall surface excluding the side wall surface into which the light is introduced, the first and first light reflected by the reflection layer is used. The two liquid crystal display panels are irradiated, and the luminance of the first and second liquid crystal display panels can be increased by effectively using the light from the light source.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. However, the embodiment shown below exemplifies a foldable portable information terminal for embodying the technical idea of the present invention, and is intended to specify the present invention as this foldable portable information terminal. Rather, other embodiments within the scope of the claims are equally applicable.

  FIG. 1 is an exploded perspective view of a liquid crystal display device used in a foldable portable information terminal according to an embodiment of the present invention, FIG. 2 shows the liquid crystal display device assembly of FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A, FIG. 3 shows a circuit board mounted on the liquid crystal display device, and FIG. 3A is a front perspective view. 3B is a rear perspective view, FIG. 4 shows a sheet metal frame mounted on the liquid crystal display device, FIG. 4A is a front perspective view, FIG. 4B is a rear perspective view, and FIG. FIG. 6 is a block diagram showing a control circuit for a display panel and a light source LED, FIG. 6 shows a foldable mobile phone in which a liquid crystal display device is incorporated, and FIG. 6 (A) is a perspective view seen from one side with the phone open. 6 (B) is a perspective view seen from the other side. Incidentally, the front and back of the circuit board and the sheet metal frame shown in FIGS. 3 and 4 are described with the surface on which the first liquid crystal display panel is provided as the front surface and the surface on which the second liquid crystal display panel is provided as the back surface.

  The liquid crystal display device 10 used in the foldable portable information terminal of the present invention includes a light guide plate 11 that guides light to both the front and back surfaces, and a first liquid crystal display panel disposed on the front surface 11a side of the light guide plate 11. 15 and a second liquid crystal display panel 30 that is smaller than the first liquid crystal display panel 15 disposed on the back surface 11 b side of the light guide plate 11. The back surface 11 b of the light guide plate 11 has substantially the same size as the light guide plate 11. The first liquid crystal display panel 15, the light guide plate 11, and the second liquid crystal display panel are brought into contact with each other by bringing a thin sheet metal frame 25 having an opening 26 having substantially the same size as the display surface of the second liquid crystal display panel 30 into contact therewith. 30 is laminated, this laminated body is covered with a cover 40, and the surface of the second liquid crystal display panel 30 is fixedly exposed through an opening 42 provided in the cover 40.

  As shown in FIGS. 1 and 2, the light guide plate 11 is formed of a thin plate-like body, introduces light emitted from the light source 14 into the inside from one end portion 11 c thereof, and is on the surface 11 a side (first side) of the light guide plate 11. The liquid crystal display panel 15 side) and the back surface 11b side (second liquid crystal display panel 30 side) are led out and formed of a transparent material. As the transparent material, for example, an acrylic resin material is used. The thickness is preferably about 0.6 mm, and a reflective layer is applied to the side wall surface other than the one end 11c to which the light source 14 is attached. This reflective layer is provided so that light supplied through the light guide plate 11 does not leak from other than the surface on which the liquid crystal display panels 15 and 30 are provided. The light guide plate 11 is fitted into a frame-shaped frame body 12.

  As shown in FIGS. 1 and 2B, the frame-like frame body 12 into which the light guide plate 11 is fitted is composed of frame pieces 12 a to 12 d having a rectangular shape and a predetermined width and height. The liquid crystal display panel 15, the light guide plate 11, the optical sheets 17a and 17b, and the light source 14 are large enough to be accommodated.

  Among these frame pieces 12a to 12d, when opposing long side frame pieces 12c and 12d are extended longer than the light guide plate 11, the frame piece 12a is provided at the tip thereof, and when the light guide plate 11 is fitted into the frame body 12, A gap 12a ′ is formed between the frame piece 12a and the light guide plate 11. The light source 14 is inserted into the gap 12a 'when the liquid crystal display panel is assembled.

  The first liquid crystal display panel 15, the optical sheets 17 a and 17 b, and the light guide plate 11 are fitted into the frame-shaped frame body 12. By fitting each component into the frame body 12 in this way, one assembly is formed. Therefore, the assembly of the liquid crystal display panel in the next process is simplified.

  Further, a member for fixing the first liquid crystal display panel 15 is not required, the assembly of the liquid crystal display panel is simplified, and the mechanical strength can be increased.

  A plurality of light emitting diodes (LEDs) 13a are used for the light source 14, and these are mounted in a row on a long and narrow substrate 13, and power is supplied through wiring 13b connected to the substrate. Is done. In addition, these LEDs are monochromatic LEDs or LEDs that emit R (red), G (green), and B (blue).

  A transmissive liquid crystal display panel is used as the first liquid crystal display panel 15. As shown in FIG. 2B, the liquid crystal display panel 15 includes a liquid crystal 15c enclosed between two first and second substrates 15a and 15b made of opposing glass via a sealing material. It has a bonded structure. Of the substrates 15a and 15b, the second substrate 15b is longer than the first substrate 15a so that the end of the second substrate 15b protrudes from the edge of the first substrate 15a when the substrates are bonded together. use. And the light source 14 is affixed on the back surface of this protrusion part 15b '. Note that the transmissive liquid crystal display panel used here is a known one and will not be described in detail.

  Further, deflecting plates 16a and 16b are provided on the front and back surfaces of the first liquid crystal display panel 15, respectively. Between the liquid crystal display panel 15 and the light guide plate 11, an optical made of a light diffusion sheet, a prism sheet or the like is provided. A sheet 17a is provided.

  The first liquid crystal display panel 15 has a circuit board 18 connected to one end thereof. The circuit board 18 has a graphic controller, a light source (LED) driver, a semiconductor element for driving liquid crystal, and the like mounted on a flexible printed circuit (FPC). As shown in FIG. 2, the control board 19 has approximately the same size as the first liquid crystal display panel 15 and a connection portion 20 that connects the control board 19 and the first liquid crystal display panel 15. In addition, the circuit board 18 can be folded from the connecting portion 20 during assembly.

  FIG. 5 is a block diagram showing a control circuit for each liquid crystal display panel and the light source LED, and these circuits are mounted on the circuit board 18.

  The control circuit 45 includes a liquid crystal control circuit 46 that controls the first and second liquid crystal display panels 15 and 30 and an LED control circuit 47 that controls a plurality of LEDs.

  The LED control circuit 47 selectively lights up the plurality of LEDs 13a in conjunction with the driving of the first and second liquid crystal display panels. For example, when the first liquid crystal display panel 15 is illuminated, all the LEDs are turned on. When the small-sized second liquid crystal display panel 30 is illuminated, several of the plurality of LEDs 13a are turned on. Therefore, according to this lighting method, when illuminating the small-sized second liquid crystal display panel 30, not all the LEDs 13a are lit but only some of the LEDs 13a are lit, thereby suppressing battery consumption. it can. In addition, if an element that emits each color of R, G, and B is used for the plurality of LEDs 13a, a colorful display surface can be generated by lighting them in combination.

  A plurality of ground contact portions 22b are provided on the surface 19b of the circuit board 18 (see FIG. 3A), that is, the surface that contacts the back surface 25b of the sheet metal frame 25 (see FIG. 4B). These ground contact portions 22b are provided near the outer periphery of the substrate.

  On the back surface 19a of the circuit board 18, a semiconductor element 23a for driving liquid crystal, a connector 23b for connecting an external circuit, and the like are attached around the opening 21, and a plurality of ground contact portions 22a are provided. These ground contact portions 22a are connected to the ground contact portions 22b on the substrate surface, and these ground contact portions 22a and 22b are formed by applying a conductive adhesive or applying a conductive adhesive tape. Is done.

  The second liquid crystal display panel 30 is a transflective or transmissive liquid crystal display panel. The second liquid crystal display panel 30 is formed by joining and integrating a first substrate 30a and a second substrate 30b made of glass or the like, which are opposed to each other with a liquid crystal layer interposed therebetween, with a sealing material, and the second substrate 30b is connected to the display surface. It has become.

  A flexible substrate 31 is connected to the liquid crystal display panel 30, and the other end of the substrate 31 is connected to the circuit board 18 via a connector.

  The sheet metal frame 25 has substantially the same size as the frame-like frame body 12, and has an opening 26 having the same size as the display surface of the second liquid crystal display panel 30 on its surface and a plurality of edges on the outer peripheral edge. And is formed of a thin metal material such as aluminum, and the plate thickness is preferably about 0.2 mm.

  The sheet metal frame 25 is mirror-finished on one surface 25 a, that is, the surface in contact with the light guide plate 11. The mirror surface processing is performed by, for example, polishing, vapor deposition, sputtering, or application of a coating material containing a metal material such as silver. By applying a mirror finish to this surface, a part of the light introduced into the light guide plate 11 is reflected by this surface and irradiates the first liquid crystal display panel 15, and thus the light supplied from the light source 14 is irradiated. Efficient use is possible.

  Further, on the back surface 25b of the sheet metal frame 25, that is, the surface on which the second liquid crystal display panel 30 is mounted, a plurality of protruding pieces 29a, 29b, 29c protruding from the surface are formed on the three sides of the opening 26. Is done. These projecting pieces 29 a, 29 b and 29 c are in contact with the outer peripheral surface of the second liquid crystal display panel 30 and position the second liquid crystal display panel 30. The second liquid crystal display panel 30 and the optical sheet (not shown) provided on the back surface of the second liquid crystal display panel 30 are fixed by these protrusions 29a, 29b, 29c and a cover 40 described later. That is, the second liquid crystal display panel 30 and the optical sheet provided on the back surface of the second liquid crystal display panel 30 are positioned on three sides of the protrusions 29a, 29b, and 29c, covered with the cover 40, and provided on the cover 40. The outer periphery of the second liquid crystal display panel 30 is pressed and fixed around the opening 42. According to this method, a dedicated frame for fixing the panel 30 and the like is not necessary, and the assembling work is simplified.

  As shown in FIG. 4B, the back surface 25b of the sheet metal frame 25 is formed with a plurality of ground contact portions 25b ′ at the outer peripheral end portion, and double-sided adhesive is applied to the portion excluding the electrode 25b ′ and the opening 26. Tape T is stuck. Each ground contact portion 25b 'is formed by applying a conductive adhesive or applying a conductive adhesive tape.

  When the double-sided adhesive tape T is affixed to the back surface 25b of the sheet metal frame 25 and the conductive adhesive is applied to the ground contact portion 25b ′, the circuit board 18 is placed on one side of the double-sided adhesive tape T when the liquid crystal display panel is assembled. At the same time, the ground contact portion 22b of the circuit board 18 is attached to the conductive adhesive.

  Therefore, the circuit board 18 is firmly fixed to the sheet metal frame 25, and each ground contact portion 22b is securely connected.

  Thus, by using the metal plate frame 25 made of a metal material, a predetermined mechanical strength is maintained, and the metal plate frame 25 can be brought into contact with the light guide plate 11 and supported while being mechanically reinforced. Even if the sheet metal frame 25 is thin, it can maintain a predetermined mechanical strength. Therefore, even if this component is added and the thickness of the light guide plate and the first and second liquid crystal display panels is reduced, the liquid crystal display device 10 as a whole. Can be made thinner. Further, the sheet metal frame 25 has a function of extending wrinkles of the optical sheet and preventing wrinkles by contacting the optical sheet interposed between the frame 25 and the light guide plate 11. Furthermore, since the sheet metal frame 25 is a conductor, a good electrical connection circuit can be formed between the circuit board 18 and a cover 40 described later, and an earth connection can be made through this circuit connection.

  The sheet metal frame 25 is not limited to a metal material, and may be a sheet material made of a resin material having a predetermined strength.

  As shown in FIGS. 1 and 2, the cover 40 is formed from the second liquid crystal display panel 30 side after the first liquid crystal display panel 15, the light guide plate 11, the sheet metal frame 25, the second liquid crystal display panel 30, and the like are laminated. It is a cover that covers this laminated body, has a box shape having shallow side plates 41a to 41d on the outer periphery with a shallow bottom, and the second liquid crystal display panel 30 on the bottom plates 41f and 41g having the same flat surface height. And a plurality of openings 43 through which the connector 23b provided on the circuit board 18 is exposed, and is formed of a metal material. The bottom plates 41f and 41g project a portion of the circuit board 18 in contact with the ground contact portion 22a inward to form a projecting portion (not shown) to improve the contact with the ground contact portion 22a during assembly. Is preferred. The metal material is preferably a stainless steel material, but is not limited to the stainless steel material, and may be another metal material or a resin material.

  The assembly of the liquid crystal display device provided with the double-sided light emitting type light guide plate will be described below.

  First, the light guide plate 11 is fitted into the frame-shaped frame body 12, and one or a plurality of optical sheets 17a are placed on one surface 11a of the fitted light guide plate, and a first liquid crystal display is formed from above the optical sheet 17a. The panel 15 is fitted into the frame body 12. Similarly, the other surface 11b of the light guide plate 11 has one or more optical sheets 17b mounted thereon, and has an opening for exposing the display surface of the second liquid crystal display panel 30 on the optical sheet 17b. A light shielding sheet (not shown) is attached.

  This light shielding sheet shields the light from the light guide plate 11 from being irradiated to the outer periphery of the small second liquid crystal display panel 30. In addition, by fitting the first liquid crystal display panel 15, the optical sheets 17a and 17b, and the light guide plate 11 in the frame-shaped frame 12, these components are accommodated in the frame 12 to form one assembly. This simplifies the assembly of the liquid crystal display panel in the next process. In addition, a member for fixing the first liquid crystal display panel is unnecessary, the assembly of the liquid crystal display panel is simplified, and the mechanical strength can be increased.

  Next, the sheet metal frame 25 is brought into contact with the back surface of the light shielding sheet of the assembly, and the locking pieces 27a of the sheet metal frame 25 are engaged with the locking protrusions 12e of the frame body 12 to be fixed.

  In addition, a double-sided adhesive tape T is applied to the sheet metal frame 25 in advance, and a conductive adhesive is applied to the contact portion 25b ′ for grounding, and between the protrusions 29a to 29c around the opening 26. The second liquid crystal display panel is sandwiched.

  Thereafter, the circuit board 18 is affixed to one surface of the double-sided adhesive tape T, and the ground contact portion 22b of the circuit board 18 is electrically connected to the ground contact portion 25b ′ of the sheet metal frame 25 via a conductive adhesive. To do.

  The assembly assembled in this manner is covered with the cover 40 from the second liquid crystal display panel 30 side, and the locking hole 41e of the cover 40 is locked to the locking projection 12f of the frame 12, so The liquid crystal display device 10 provided with the light plate is assembled. By covering the assembly with the cover 40 as described above, the connector 23b of the circuit board 18 is exposed from the opening provided in the cover 40, and connection to other devices is performed via this connector 23b. The ground contact portion 22 a of the circuit board 18 is electrically connected to the inner wall surface of the cover 40.

  By this assembly, the ground contact portions 22a and 22b of the circuit board 18 are electrically connected to the ground contact portion 25b 'of the sheet metal frame 25 and the cover 40, so that generation of noise can be suppressed. In addition, since the first and second liquid crystal display panels 15 and 30 and the circuit board 18 are covered with the cover, the whole is shielded and the influence of electromagnetic waves can be reduced.

  The assembled liquid crystal display device is mounted on a mobile terminal, for example, a mobile phone.

  6A and 6B show a foldable mobile phone in which a liquid crystal display device is incorporated. FIG. 6A is a perspective view seen from one side with the phone open, and FIG. 6B is a perspective view seen from the other side.

  As shown in FIGS. 6A and 6B, the folding cellular phone 50 includes an upper housing 51 and a lower housing 52 that are connected to each other by a hinge mechanism 53 so as to be freely opened and closed.

  The upper housing 51 incorporates the liquid crystal display device 10, and the operation surface 52 a of the lower housing 52 is provided with a predetermined number of input keys 52 b for performing dial operations and the like. The upper surface of 51 and the input key 52b are mirror-finished. This mirror finishing is performed by applying a metal material, for example, a paint containing silver.

  In the cellular phone 50 in which the liquid crystal display device 10 is mounted, the first liquid crystal display panel 15 is normally used when the housings 51 and 52 are used in an open state. The light is applied to both the liquid crystal display panels 15 and 30 through the light guide plate 11, and the light applied to the mirror-finished surface 25a of the sheet metal frame 25 is reflected to the first liquid crystal display panel 15 side. Since the first liquid crystal display panel 15 is irradiated, the first liquid crystal display panel 15 can have high luminance.

  Further, when the housings 51 and 52 are used in a folded state, the first liquid crystal display panel 15 is sandwiched between the housings 51 and 52 and thus cannot be seen. Therefore, the second liquid crystal display panel 30 is usually used. At this time, since the first liquid crystal display panel 15 is not in a visible state, no voltage is applied by the liquid crystal control circuit 46, and thus the first liquid crystal display panel 15 composed of a transmissive liquid crystal display panel is in a state of transmitting light. ing. In this case, the light derived from the light source 14 provided on the side wall surface of the light guide plate 11 is applied to both the liquid crystal display panels 15 and 30 through the light guide plate 11 and is applied to the first liquid crystal display panel 15. The light is reflected to the second liquid crystal display panel 30 side by the mirror-finished operation surface 52a, that is, the upper surface of the lower housing 51 and the input key 52b, so that the second liquid crystal display panel 30 is irradiated with high brightness. Become.

  In addition, when the second liquid crystal display panel 30 is used as described above, only a part of the LED 13a serving as a light source is used by the LED control circuit 47. Thereby, the power consumed by the light source can be suppressed while maintaining the predetermined luminance or higher of the second liquid crystal display panel 30, and a power saving effect can be obtained.

  As described above, according to the foldable portable information terminal of the present invention, both the liquid crystal display panels can be kept at high brightness even when used in the opened state and the folded state. When irradiating, a power saving effect can also be obtained.

  Further, since the liquid crystal display device 10 is thinned by the above-described configuration, the mobile phone equipped with the liquid crystal display device 10 can also be thinned. In addition, the apparatus which mounts this liquid crystal display device 10 is not limited to a mobile telephone, It can mount also in another portable information terminal, for example, PDA etc.

FIG. 1 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention. 2 shows the liquid crystal display device assembly of FIG. 1, FIG. 2 (a) is a plan view, and FIG. 2 (b) is a cross-sectional view taken along line AA of FIG. 2 (a). 3 shows a circuit board mounted on the liquid crystal display device of the present invention. FIG. 3 (a) is a front perspective view, and FIG. 3 (b) is a rear perspective view. FIG. 4 shows a sheet metal frame mounted on the liquid crystal display device of the present invention, FIG. 4 (a) is a front perspective view, and FIG. 4 (b) is a rear perspective view. FIG. 5 is a block diagram showing a control circuit for each liquid crystal display panel and light source LED. 6A and 6B are diagrams showing a foldable mobile phone, FIG. 6A is a perspective view seen from one side with the phone open, and FIG. 6B is a perspective view seen from the other side. FIG. 7 is a perspective view showing a conventional folding mobile phone. FIG. 8 is a side view showing a conventional liquid crystal display module. FIG. 9 is an exploded perspective view showing a double-sided liquid crystal display device mounted on a conventional folding mobile phone.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 11 Light guide plate 12 Frame 13a Light emitting diode element 14 Light source 15 1st liquid crystal display panel 18 Circuit board 25 Sheet metal frame (reinforcement frame)
30 Second liquid crystal display panel 40 Cover 50 Foldable mobile phone 51 Upper housing 52 Lower housing 45 Control circuit 46 Liquid crystal control circuit 47 LED control circuit

Claims (5)

A light guide plate that guides light introduced from a light source provided on the side wall surface to both the front and back surfaces, and a first liquid crystal display that transmits light when no voltage is applied across the light guide plate. A display unit housing having a panel and a second liquid crystal display panel smaller than the first liquid crystal display panel, and a control means for controlling lighting of the light source, and an operation unit housing having an operation key. In the foldable portable information terminal in which the operation case and the operation unit case are coupled by a coupling mechanism and can be folded, and the operation key and the first liquid crystal display panel face each other when folded. The unit housing has a mirror-finished surface facing the first liquid crystal display panel, and uses a plurality of light emitting diode elements as the light source. The control means selectively lights the plurality of light emitting diode elements. in front First, foldable portable information terminal and performs illumination of the second liquid crystal display panel. The control means turns on all the plurality of light emitting diode elements when using the first liquid crystal display panel, and out of the plurality of light emitting diode elements when using the second liquid crystal display panel. 2. The folding portable information terminal according to claim 1, wherein a part of the portable information terminal is controlled to be lit. A thin plate-shaped reinforcing frame is provided on a surface of the light guide plate provided in the display housing on which the second liquid crystal display panel is placed so as to surround the second display panel. 2. The foldable portable information terminal according to claim 1, wherein the surface on the side in contact with the optical plate is mirror-finished. The foldable portable information terminal according to claim 1, wherein the mirror finish of the operation unit casing is also applied to a surface of the operation key. The foldable portable information terminal according to claim 1, wherein the light guide plate has a reflective layer formed on an outer peripheral side wall surface excluding a side wall surface into which light is introduced.

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