JP2010218878A - Input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a liquid crystal display panel from giving rise to display failure even after use for a long period, and yet enable to obtain enough click feeling at input operation. <P>SOLUTION: The liquid crystal display panel 20 are arranged overlapped on a switch sheet 10 with a plurality of dome switches 10S formed at intervals on a substrate 11. The liquid crystal display panel 20 pinches a liquid crystal layer 213 between resin substrates 211, 212 transparent with flexibility, on an outside face of which 211, 212, deflection plates 22, 23 are adhered, and a virtual operating button is displayed for each display area 20a corresponding to the dome switches 10S. By pressing each display area 20a of the liquid crystal display panel 20, the corresponding dome switch 10S is pressed to perform switching operation. Slits 22s, 23s are formed at a part corresponding to a periphery of each display area 20a of each deflection plate 22, 23 of the liquid crystal display panel 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides an input in which a liquid crystal display panel for displaying a virtual operation button corresponding to each dome switch is provided on a switch sheet provided with a dome switch (also referred to as a membrane switch or a tact switch) for detecting pressing. Relates to the device.

The switch sheet and the liquid crystal display panel are stacked and arranged, and the switch area of the switch sheet is operated by pressing (touching) the display area of the virtual operation button displayed on the liquid crystal display panel with a fingertip. 2. Description of the Related Art Input devices that input selections, instructions, and the like and provide various functions and services according to the selections are widely known.
For example, such an input device is adopted for a mobile phone or various office equipments, and by switching the display of the virtual operation buttons in the same touch area, a plurality of different inputs can be performed, and many types of panels can be obtained with a small area panel. Making it possible to input.

As such an input device, conventionally, a glass substrate is generally used as the substrate of the liquid crystal display panel. Therefore, it is difficult to transmit the pressing force to the switch sheet due to poor flexibility. Many LCD panels were arranged on the side.
For this reason, all of the substrate constituting the switch sheet, the fixed contact of the dome switch, the dome-shaped movable contact, etc. must be made of a transparent material, which has a large material restriction. Moreover, since the display of the virtual operation button on the liquid crystal display panel is visually recognized through the switch sheet, there is a problem that visibility is impaired.

  Therefore, recently, an input device in which a liquid crystal display panel is provided with flexibility by using a transparent resin substrate to enable transmission of a pressing force and the liquid crystal display panel is provided on the upper side of the switch sheet is provided. It has been put into practical use. For example, Patent Document 1 proposes such an input device.

  The input device (referred to as an input / output device) described in Patent Document 1 is a flat membrane switch in which the coordinate detecting means corresponding to the switch sheet has no dome-shaped convex portions, and the liquid crystal Each polarizing plate provided by adhering to the outer surfaces of the upper and lower transparent resin substrates of the display panel is thicker and more rigid than the resin substrate even though it is made of resin. Moreover, in order to disperse local stress from the viewing side of the liquid crystal display panel, a buffer layer is provided between the viewing side resin substrate and the polarizing plate, or between the lower polarizing plate and the membrane switch. In addition, a reinforcing plate for protecting the liquid crystal display panel is provided.

In such an input device, the visibility of the liquid crystal display panel is good and local stress is dispersed, so that it is unlikely that the liquid crystal display panel will deteriorate and display defects will not occur even if it is used for a long time. Is done.
However, when the membrane switch is operated by pressing the liquid crystal display panel from the viewing side, the pressing force is dispersed to the surroundings by a highly rigid polarizing plate, and further weakened via a buffer layer or a reinforcing plate. Since the switch has a structure in which the amount of elastic deformation and the return force of the switch are small, the click feeling as the operation feeling is extremely poor, and it is uneasy whether the switch operation has been performed reliably. Actually, the pressing force applied to the display area of the virtual operation button of the liquid crystal display panel may be dispersed to the surroundings, and may not be sufficiently transmitted to the membrane switch, so that a reliable switch operation may not be performed.

Here, the click feeling will be briefly described with reference to FIG. FIG. 12 is a diagram showing the relationship between the pressing stroke S, the operating force P1, and the restoring force P2 in such a touch input device, and the click rate is obtained by the following equation.
Click rate = (P1-P2) / P1
Therefore, the click rate increases as the difference between the peak of the operation force and the return force increases, and a click feeling, that is, an operation feeling can be sufficiently obtained.

  In order to increase the click feeling in such an input device, for example, as shown in FIG. 13, each switch of the switch sheet 100 is a dome switch 110 formed in a dome shape with a movable contact portion bulging upward, Conventionally, an actuator (presser) 300 for efficiently transmitting a pressing force to the dome switch 110 is interposed between each dome and the lower surface of the liquid crystal display panel 200.

  In this example, the switch sheet 100 has a circular fixed contact 111 on a substrate 120 and a ring-shaped fixed contact 112 spaced from the outer periphery thereof, made of metal, and has a spring-like metal dome like a spherical part. The base of the (movable contact) 113 is connected to or placed on the ring-shaped fixed contact 112, and a resin sheet 115 is adhered to the outer side thereof with an adhesive layer 114 to constitute the dome switch 110. The actuator 300 is held by a flexible sheet 310.

  According to such an input device, the pressing force from the upper surface side of the liquid crystal display panel 200 is efficiently transmitted to the dome switch 110 via the actuator 300, and the metal dome 113 is elastically deformed to make the fixed contacts 111 and 112 conductive. Then, it is pushed back by its restoring force, so that a reliable switch operation is performed and a sufficient click feeling is obtained.

Japanese Patent No. 3463501

  However, in such an input device, if a switch input operation is repeated many times, concentrated stress is repeatedly applied to the portion of the lower surface of the liquid crystal display panel that contacts the actuator, so that the resin substrate of the liquid crystal display panel is slightly recessed and the substrate There was a problem in that the display quality deteriorated due to gap unevenness and poor alignment. As the area of the tip of the actuator is reduced in order to enhance the click feeling, such display defects are more likely to occur.

  The present invention has been made in view of such a situation, and in an input device in which a liquid crystal display panel is overlaid on a switch sheet as described above, a display defect occurs in the liquid crystal display panel even if it is used for a long period of time. The object is to obtain a sufficient click feeling during an input operation.

In order to achieve the above object, the present invention includes a switch sheet having a plurality of dome switches and a liquid crystal display panel disposed on the switch sheet, the liquid crystal display panel having two flexible sheets. A liquid crystal layer is sandwiched between the two substrates, a polarizing plate is provided on the outer surface of each of the two substrates that does not contact the liquid crystal layer, and a virtual operation button is displayed for each display area corresponding to the dome switch. The input device is configured such that when each display area of the liquid crystal display panel is pressed from the viewing side, the dome switch corresponding to the switch sheet is pressed to perform a switch operation.
A slit is formed in a portion corresponding to the periphery of each display area in at least one of the polarizing plates.

It is desirable to form the slits at positions corresponding to the portions corresponding to the periphery of the display areas of both the polarizing plates.
Further, the slit can be formed in an endless shape (ring shape or the like) or divided into a plurality of portions (arc-shaped portions or the like) so as to surround portions corresponding to the display areas of the polarizing plate.

Instead of forming the slit, at least one of the polarizing plates provided on the outer surface of each of the two substrates of the liquid crystal display panel may be provided only in a region corresponding to the display region. Good.
Both the polarizing plates may be provided so as to face only the regions corresponding to the display regions of the liquid crystal display panel.
In these input devices, a light guide plate made of a flexible resin may be provided on the switch sheet side of the liquid crystal display panel, and a light source for illuminating the light guide plate from an end surface may be provided.

According to the input device of the present invention, a slit is formed in a portion corresponding to the periphery of the display area for displaying each virtual operation button of the polarizing plate having higher rigidity than the two substrates of the liquid crystal display panel, or the polarizing plate is displayed on each display. Since it is provided only in the area corresponding to the area, when the area where the virtual operation button is displayed is pressed, the pressing force is not distributed to the surroundings by the polarizing plate or is transmitted to the dome switch efficiently. The switch operation by elastic deformation of the dome-shaped movable contact piece of the dome switch can be surely performed, and the restoring force is efficiently transmitted to the pressing portion of the liquid crystal display panel, so that a sufficient click feeling can be obtained.
In addition, since the actuator (pushing element) is not provided, the liquid crystal display panel is not damaged even if the pressing operation is repeated, so that there is no possibility of display failure. Furthermore, the input device can be easily reduced in thickness and weight.

It is a perspective view which simplifies and shows the appearance of a 1st embodiment of an input device by this invention. It is a typical expanded sectional view which follows the AA line of FIG. It is a partially expanded sectional view which shows the layer structure of the upper and lower polarizing plates in FIG. It is a perspective view which simplifies and shows the external appearance of embodiment which changed the shape of the slit formed in a polarizing plate.

It is a partial enlarged plan view which shows the example in the case of forming a slit in multiple divided | segmented into the polarizing plate, when the shape of the display area which displays each virtual operation button of a liquid crystal display panel is substantially square. Similarly, it is a partial enlarged plan view showing an example of forming an endless slit in the polarizing plate when the shape of the display region is substantially square. It is a perspective view which simplifies and shows the external appearance of 2nd Embodiment of the input device by this invention. It is a typical expanded sectional view which follows the BB line of FIG.

It is a layout figure which shows an example of the segment electrode formed in the inner surface of one board | substrate of a liquid crystal cell. It is the layout figure which shows the other example of a segment electrode similarly. It is a perspective view which shows the mobile telephone carrying the input device by this invention in the state which opened the main display part. It is a diagram which shows the relationship between the stroke S of the press in a touch type input device, the operation force P1, and the return force P2. It is typical sectional drawing which shows the structural example of the input device which increased the conventional click feeling.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment: FIGS. 1 to 6]
FIG. 1 is a perspective view showing a simplified appearance of a first embodiment of an input device according to the present invention. 2 is a schematic enlarged cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a partially enlarged cross-sectional view showing the layer structure of the upper and lower polarizing plates.

  In the input device shown in FIG. 1, a liquid crystal display panel 20 is laminated on a switch sheet 10. The liquid crystal display panel 20 displays a virtual operation button for each display area 20a corresponding to a dome switch (to be described later) of the switch sheet 10, and presses each display area 20a from the viewing side, thereby corresponding to the switch sheet 10. The dome switch is pressed to perform a switch operation.

  A slit 22 s is formed in a portion corresponding to the periphery of each display region 20 a of the upper polarizing plate 22 provided on the viewing side of the liquid crystal display panel 20. In this embodiment, four arc-shaped slits 22s corresponding to each part obtained by dividing a circle surrounding the circumference of each circular display area 20a into four are formed around one display area 20a, and the upper polarizing plate 22 is formed. A portion corresponding to the display area 20a inside the slit 22s and a portion outside the slit 22s are joined together at a portion where the slits left at intervals of 90 ° are not formed.

The configuration of this input device will be described in more detail with reference to FIGS.
In the input device of this embodiment, as shown in the enlarged sectional view of FIG. 2, the switch sheet 10 and a flexible liquid crystal display panel 20 are stacked with a light guide plate 30 interposed therebetween. Reference numeral 40 denotes a light emitting diode (LED) as a light source for illuminating the light guide plate from its end face.

  The switch sheet 10 forms a plurality of dome switches 10S at intervals on the substrate 11, and each dome switch 10S has a ring-shaped fixed contact 12 on the substrate 11 and an interval from its outer periphery. The fixed contact 13 is formed of copper foil, and a dome-shaped movable contact piece 14 is disposed so as to cover the fixed contact 13 with a space therebetween, and the fixed contact 15 is covered with a fixed sheet 15 bonded to the substrate 11. Thus, the dome-shaped movable contact piece 14 is positioned and held.

The substrate 11 is made of an insulating resin such as polyimide and has a thickness of about 0.025 mm. The dome-shaped movable contact piece 14 is formed of a springy SUS material (stainless steel), and when pressed, it is elastically deformed, the peripheral part expands, the upper part descends, and the fixed contacts 12 and 13 are made conductive. Turn on the switch. When the pressing force is weakened, it returns to the OFF state shown in the figure by the elastic restoring force.
The fixing sheet 15 is made of an insulating resin such as PET (polyethylene terephthalate) and has a thickness of about 0.063 mm.

  The liquid crystal display panel 20 has a total thickness of about 0.528 mm, a liquid crystal cell 21 having a liquid crystal layer 213 sandwiched between an upper substrate 211 and a lower substrate 212, which are two transparent resin substrates having flexibility. The upper polarizing plate 22 and the lower polarizing plate 23 are bonded to the outer surfaces of the two resin substrates 211 and 212 that are not in contact with the liquid crystal layer 213, and correspond to the dome switches 10S of the switch sheet 10. Each display area 20a has a function of displaying a virtual operation button.

  The upper substrate 211 and the lower substrate 212 of the liquid crystal cell 21 are each formed of, for example, PC (polycarbonate) to a thickness of about 0.126 mm, and the liquid crystal layer 213 includes an upper substrate 211 and a lower substrate 212 and a sealing material (not shown). Is a layer having a thickness of about 0.006 mm, in which TN (twisted nematic) liquid crystal is injected into the space formed in (1). In order to keep the thickness of the liquid crystal layer 213 constant, spacers (not shown) fixed to the upper substrate 211 or the lower substrate 212 are formed by photolithography.

Further, a common electrode is formed on the entire inner surface of one of the upper substrate 211 and the lower substrate 212, and a segment electrode for displaying the type of the virtual operation button is formed on the other surface by a transparent ITO (indium tin oxide) film. An alignment film made of polyimide is formed on the entire inner surface including the surface, but these are also not shown.
As materials for the upper substrate 211 and the lower substrate 212, PET, PES (polyethersulfone), or the like can be used in addition to PC.

  As shown in FIGS. 3A and 3B, the upper polarizing plate 22 and the lower polarizing plate 23 have a thickness of 0 on both sides of PVA (polyvinyl alcohol) sheets 221 and 231 having a thickness of about 0.03 mm. TAC (cellulose triacetate film) 222, 223 and 232, 233 of about .04 mm are closely stacked. The upper polarizing plate 22 has an adhesive layer 224 formed on the lower surface of the lower TAC 223 with a thickness of about 0.025 mm, and the lower polarizing plate 23 has an adhesive layer 234 formed on the upper surface of the upper TAC 233 with a thickness of about 0.025 mm. Forming.

In general, in a TN liquid crystal display panel, the upper polarizing plate 22 and the lower polarizing plate 23 both transmit linearly polarized light having a vibration surface in a direction parallel to the polarization axis, and have a vibration surface in a direction perpendicular to the polarization axis. Polarized light is an absorptive polarizing plate that absorbs light, and the polarization axes thereof are arranged parallel or orthogonal to each other.
When the liquid crystal layer 213 is a TN liquid crystal layer, the linearly polarized light incident on the liquid crystal layer 213 from the light guide plate 30 through the lower polarizing plate 23 and the lower substrate 212 is rotated by 90 ° in the liquid crystal layer 213 in a portion where no voltage is applied. And reaches the upper polarizing plate 22.

Therefore, when the polarization axes of the upper polarizing plate 22 and the lower polarizing plate 23 are parallel, they are absorbed by the upper polarizing plate 22, so that a normal black display is obtained. In a portion where a voltage is applied between the common electrode and the segment electrode, Since the linearly polarized light incident on the liquid crystal layer 213 reaches the upper polarizing plate 22 as it is, it is transmitted therethrough and emitted to the viewing side, and is displayed in a color corresponding to the color of the light source.
Although the normal black display is used in this embodiment, the polarization axes of the upper polarizing plate 22 and the lower polarizing plate 23 may be orthogonal to each other. In this case, the linearly polarized light that has entered the liquid crystal layer 213 from the light guide plate 30 through the lower substrate 210 passes through the upper polarizing plate 22 and exits to the viewing side when no voltage is applied, so normal white (the color of the light source) In the display, the segment electrode portion to which the voltage is applied is displayed in black. At this time, it is preferable that a transflective plate is inserted between the liquid crystal display panel 20 and the light guide plate 30 to enable reflective display.

  In this embodiment, as described with reference to FIG. 1, slits 22 s are formed in a portion of the upper polarizing plate 22 corresponding to the periphery of each display area 20 a where the liquid crystal display panel 20 displays virtual operation buttons. In addition, slits 23 s are formed at positions corresponding to the periphery of each display region 20 a in the lower polarizing plate 23 at positions corresponding to the slits 22 s of the upper polarizing plate 22.

  The light guide plate 30 is a PC (polycarbonate) sheet having a thickness of 0.15 mm, and introduces illumination light from the light emission of the LED 40 as a light source from one end face thereof. Then, the illumination light is repeatedly reflected and diffused on the front and back surfaces of the light guide plate 30, and the lower surface of the liquid crystal display panel 20 is illuminated with substantially uniform brightness as a backlight to cause the liquid crystal display panel 20 to display. Thereby, clear display is performed even in a dark environment. In order to prevent light from leaking from the slit 22s, a light shielding layer 30s is printed at a portion corresponding to the slit 22s portion of the light guide plate 30.

  The LED 40 generally emits white light, but may emit light of yellow or other colors, or display colors using red, green, and blue multicolor LEDs. Switching may be performed, or field sequential color display may be performed. A linear light source or a surface light source may be used as the light source. However, the light guide plate 30 and the light source such as the LED 40 constituting the backlight are not essential for the present invention.

  According to this input device, portions corresponding to the periphery of the display area 20a for displaying the respective virtual operation buttons of the upper polarizing plate 22 and the lower polarizing plate 23, which have higher rigidity than the upper substrate 211 and the lower substrate 212 of the liquid crystal display panel 20. Since the slits 22s and 23s are formed, when the area 20a where the virtual operation button is displayed is pressed, the pressing force is hardly dispersed by the polarizing plates 22 and 23, and the dome switch 10S is efficiently provided. Communicated. Therefore, the switch operation by elastic deformation of the dome-shaped movable contact piece 14 of the dome switch 10S can be surely performed, and the restoring force is also efficiently transmitted to the pressing portion of the liquid crystal display panel 20, so that a sufficient click feeling can be obtained. can get.

Further, since the actuator (pushing element) is not provided, the liquid crystal display panel 20 is not damaged even if the pressing operation is repeated, and there is no possibility that a display defect occurs.
Furthermore, since no additional members such as an actuator, a buffer material, and a reinforcing plate are provided, the input device can be easily reduced in thickness and weight.

  In this embodiment, since slits are formed in both the upper polarizing plate 22 and the lower polarizing plate 23, the effect of increasing the click feeling is great. However, the slit is formed in only one of the upper polarizing plate 22 and the lower polarizing plate 23. Even if it forms, compared with the case where a slit is not formed, a click feeling can be improved considerably. If the slit 22 s is formed in the upper polarizing plate 22, the flatness of the upper surface of the liquid crystal display panel 20 is slightly impaired, and the appearance may deteriorate depending on the application. In such a case, the slit 23 s is formed only in the lower polarizing plate 23. do it.

  Note that the number of slits formed in the polarizing plates 22 and 23 is not limited to four at positions corresponding to the periphery of one display region 20a of the liquid crystal display panel 20, but may be two, three, or five or more. The slits may not be the same length.

  FIG. 4 is a perspective view showing a simplified appearance of an embodiment in which the shape of the slit formed in the polarizing plate is changed. In this example, slits 22 s are formed in an endless shape (ring shape in the illustrated example) so as to surround a portion corresponding to the display region 20 a of the upper polarizing plate 22 of the liquid crystal display panel 20. Endless slits 23s are also formed at positions corresponding to the lower polarizing plate 23 shown in FIG. Alternatively, an endless (ring-shaped) slit may be formed only on one of the upper polarizing plate 22 and the lower polarizing plate 23.

  In this way, the pressing force when the display area 20a of the liquid crystal display panel 20 is pressed is more reliably prevented from being dispersed by the polarizing plate, and the effect of enhancing the click feeling can be increased. However, when the slit is divided and formed as in the example shown in FIG. 1, the part corresponding to the display region 20a and the part outside the slit are connected in part, and the polarizing plate is integrated, There is an advantage that the work of attaching the polarizing plate to the liquid crystal cell 21 in the manufacturing process is easy.

A plurality of divided slits may be formed in a portion corresponding to the periphery of the display region 20a in one of the upper polarizing plate 22 and the lower polarizing plate 23, and an endless slit may be formed in the other.
The shape of the display area 20a for displaying each virtual operation button of the liquid crystal display panel 20 is not limited to a circle, but can be changed to various shapes such as an ellipse, a square, and a rectangle. What is necessary is just to form a slit in the part corresponded to the circumference | surroundings of the display area 20a in at least one of 22 and the lower polarizing plate 23.

5 and 6 show an example in which the shape of the display area 20a that displays each virtual operation button of the liquid crystal display panel 20 is substantially square.
FIG. 5 shows an L-shaped slit 22s that is divided into four parts at the part corresponding to the periphery of the substantially square display area 20a in at least one of the upper polarizing plate 22 and the lower polarizing plate 23, leaving only the central part of each side. An example in which 23s is formed is shown.
In FIG. 6, endless (substantially square) slits 22s and 23s are formed over the entire circumference in a portion corresponding to the periphery of a substantially square display region 20a in at least one of the upper polarizing plate 22 and the lower polarizing plate 23. An example is shown.

[Second Embodiment: FIGS. 7 and 8]
Next, a second embodiment of the input device according to the present invention will be described with reference to FIGS. FIG. 7 is a perspective view similar to FIG. 1 of the input device, and FIG. 8 is a schematic enlarged sectional view taken along the line BB.
In the second embodiment, since the only difference from the first embodiment is the shape of the polarizing plate and the light shielding layer, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, Those explanations are omitted.

  The liquid crystal display panel 20 'of the input device of the second embodiment has the same configuration of the liquid crystal cell 21 as that of the first embodiment, but the upper polarizing plate 22' and the lower polarizing plate 23 'are replaced with a liquid crystal display panel. Only the area corresponding to the display area 20a for displaying the virtual operation buttons 20 'is provided to face each other. This corresponds to a case where all the portions outside the endless slits of the upper polarizing plate 22 or the lower polarizing plate (not shown) in the example shown in FIG. 4 are removed. The light shielding layer 30's is printed on the surface of the light guide plate 30 where there is no upper polarizing plate 22 'and no lower polarizing plate 23'.

  In order to attach such polarizing plates 22 ′ and 23 ′ to the upper substrate 211 and the lower substrate 212 of the liquid crystal cell 21, for example, in a large-sized polarizing plate provided with a protective sheet on both sides and pre-applied with an adhesive. 3 is attached to the entire surface where the adhesive layer 224 or 234 shown in FIG. 3 is not present, and the adhesive is weaker than that between the polarizing plate and the protective sheet, and the polarizing plate is formed around the area corresponding to the display area 20a on the liquid crystal cell 21. A circular notch that extends over the entire thickness of the polarizing plate 22 ', 23' is removed, and the protective sheet on the adhesive side is removed, and the entire surface of the polarizing plate with the adhesive layer 224 or 234 on top is removed. After being attached to the outer surface of the substrate 211 or the lower substrate 212, the integrated portion other than the portions left as the polarizing plates 22 'and 23' may be peeled off after peeling off the peeling mount.

  According to this embodiment, since the pressing force when the display area 20a of the liquid crystal display panel 20 'is pressed can be completely prevented from being dispersed by the polarizing plate, the click feeling at the time of key operation can be greatly enhanced. it can. Other effects are the same as in the case of the first embodiment described above.

Also in this embodiment, one polarizing plate on the upper substrate 211 side and the lower substrate 212 side of the liquid crystal cell 21 may be provided on the entire surface, and only the other polarizing plate may be provided only in a region corresponding to the display region 20a. In addition, a slit may be formed in one polarizing plate as in the first embodiment, and the other polarizing plate may be provided only in a region corresponding to the display region 20a as in this embodiment.
In addition, the shapes of the upper polarizing plate 22 'and the lower polarizing plate 23' are changed to various shapes such as an ellipse, a square, and a rectangle according to the shape of the display area 20a that displays each virtual operation button of the liquid crystal display panel 20 '. The same can be applied to changes.

[Example of segment electrode of liquid crystal cell: FIGS. 9 and 10]
Here, an example of the shape of the segment electrode formed on the inner surface of one substrate 211 or 212 of the liquid crystal cell 21 in each of the above-described embodiments will be described with reference to FIGS.
FIG. 9 shows an example of the segment electrode when two characters are switched and displayed at different parts in the same display area 20a. In this example, a segment electrode SA in the form of “A” in Roman letters is formed in the left half of the display area 20a, and a segment electrode S1 in the form of “1” in Arabic numerals is formed in the right half, which is shown in the drawing. The pattern portion of the segment electrode to which a voltage is applied between the common electrode and the common electrode is not transmissive, and light from the light guide plate 30 is emitted to the viewing side to display “A” or “1”.

When the display area 20a of the liquid crystal display panel is pressed with a fingertip or the like, an input corresponding to the character or symbol (referred to as a character or the like) displayed at that time can be made.
In this example, the display position changes depending on the characters to be displayed in the same display region 20a, and there is a drawback that the displayed characters are smaller than the area of the display region 20a. Therefore, there is a great practical advantage that wiring is simple.

  FIG. 10 shows an example of the segment electrode when two characters are switched and displayed in the same part in the same display area 20a. In this example, the six segment electrodes S2 to S7 are separated from each other with a slight gap so that the Roman letter “A” and the Arabic numeral “1” can be displayed at the same position. When a voltage is applied to the segment electrodes S2 to S5, “A” is displayed. When a voltage is applied to the segment electrodes S3, S5, S6, and S7, “1” is displayed.

In this example, two different characters or the like can be switched and displayed on the same portion in the display area 20a, so that the visibility is good. However, the segment electrode pattern becomes complicated and many depending on the characters to be combined, and so on. And the wiring to each segment electrode becomes complicated, and there is a problem that the manufacturing cost increases.
When only Arabic numerals and simple symbols are switched and displayed, a “7-segment” electrode used for general digital display may be used.

[Modifications and Applications of the Invention]
In each of the above-described embodiments of the present invention, the liquid crystal layer 213 in the liquid crystal cell 21 constituting the liquid crystal display panel 20 or 20 'has been described as an example made of TN liquid crystal, but the liquid crystal layer 213 is made of STN (super twisted nematic) liquid crystal. When forming, a phase difference plate is interposed between the liquid crystal cell 21 and the upper polarizing plate 22 or 22 '.
In that case, a slit is also formed in the retardation plate at the same position as the slit 20s of the upper polarizing plate 22, or the retardation plate and the upper portion are only provided in each region 20a displaying the virtual operation button of the liquid crystal display panel 20 ′. A polarizing plate 22 'may be provided.

Further, the liquid crystal display panel 20 or 20 'in each of the above-described embodiments is a transmissive liquid crystal display panel in which a backlight by a light source LED 40 and a light guide plate 30 is provided on the lower surface side. A reflective or absorptive liquid crystal display panel that displays using light may be used.
In that case, a reflective layer (including a white or bright diffuse reflection layer or a specular reflection layer) or a black or dark light absorption layer is provided on the lower surface side of the lower polarizing plate of the liquid crystal display panel.

In addition, even when a backlight is provided, a transflective layer or a transflective absorption layer is provided on the lower surface side of the lower polarizing plate, and a reflective or absorptive display is performed without using a backlight in a bright environment. In a dark environment, the backlight can be turned on to perform transmissive display.
In these cases, a slit is formed in the same position as the slit of the lower polarizing plate in the reflective layer, the light absorbing layer, the semi-transmissive reflective layer or the semi-transmissive absorbing layer provided on the lower surface side of the lower polarizing plate of the liquid crystal display panel. Alternatively, any one of the above layers may be provided together with the lower polarizing plate only in each region where the virtual operation buttons of the liquid crystal display panel are displayed.

Furthermore, as the lower polarizing plate, a reflective polarizing plate is used which transmits linearly polarized light having a vibration plane parallel to the polarization axis and totally reflects linearly polarized light having a vibration plane orthogonal to the polarization axis. In addition, an absorption layer, a color layer, or the like can be provided on the lower surface side to perform bright reflection type or absorption type display using external light.
In that case, the reflective polarizing plate, the absorption layer, the color layer, and the like are provided with slits similar to those provided for the lower polarizing plate described above, or only reflected in each area where the virtual operation buttons of the liquid crystal display panel are displayed. Any one of the above layers may be provided together with the mold polarizing plate.

  Further, when various coating layers such as an ultraviolet absorbing layer and an antireflection layer are provided on the upper surface of the upper polarizing plate, a slit similar to that provided for the upper polarizing plate is provided in the coating layer, or a liquid crystal is provided. It is only necessary to provide the upper polarizing plate and its coating layer only in each area where the virtual operation buttons of the display panel are displayed.

  Alternatively, as an application example of the present invention, when a scattering type liquid crystal display panel is used as the liquid crystal display panel, that is, when the liquid crystal layer in the liquid crystal cell is a light scattering type liquid crystal layer such as a polymer dispersion type (polymer network type) In the state where no voltage is applied between the electrodes sandwiching the liquid crystal layer, the refractive index of the polymer material and the liquid crystal is different, so the light is scattered and becomes opaque, and an appropriate voltage is applied. Then, since the refractive index of the polymer material and the liquid crystal becomes substantially the same, the display is made by becoming transparent.

  Therefore, polarizing plates on both sides of the liquid crystal cell are not necessary, but it is necessary to provide a reflector on the lower surface side of the lower substrate. Therefore, if the reflective plate is provided with a slit similar to that provided for the lower polarizing plate described above, or if the reflective plate is provided only in each area where the virtual operation buttons of the liquid crystal display panel are displayed, the click feeling is provided. Can be increased.

[Example of mounting on mobile phones]
Next, an example of mounting the input device according to the present invention on a mobile phone will be described. FIG. 11 is a perspective view showing a mobile phone equipped with the input device according to the present invention with the main display portion opened.

  The mobile phone 60 is connected to a main body 61 and a main display 62 so as to be openable and closable. The main display 62 is provided with a main display 63 using a color liquid crystal display panel. On the upper surface of the main body, the input device 6 according to the present invention (which may be any of the above-described embodiments) is mounted as a keypad.

  In the area where the virtual operation buttons of the liquid crystal display panel of the input device 6 are displayed, in the initial state, the same keys as the keys on the keypad of a normal mobile phone and keys such as various function selection keys are displayed. By touching each key display area, dial input, function selection, and the like can be performed. Further, the display of the virtual operation button can be changed according to the function selection, and only the next operable key can be displayed.

Since the cellular phone 60 is equipped with the input device 6 according to the present invention as a keypad, it is possible to perform an input with a click feeling when operating the keys. In addition, there is no risk of display failure of the virtual operation buttons on the liquid crystal display panel even after long-term use.
In addition, if field sequential color display is performed, only the keys that can be input in the input mode are displayed in a specific color, the display color of the key on the main panel and the display color of the key on the keypad are related, The user can freely set the color of the key, which improves fashionability and operability.

The input device according to the present invention has a sufficient click feeling during an input operation and does not damage the liquid crystal display panel. Further, since no additional member such as an actuator is provided, the input device can be easily reduced in thickness and weight.
Therefore, it is optimal as a keypad for various portable electronic devices such as mobile phones and portable terminals, and can also be applied to operation panels for other various office devices and electronic devices.

6: Input device 10: Switch sheet 10S: Dome switch 11: Switch sheet substrate 12: Circular fixed contact 13: Ring-shaped fixed contact 14: Dome-shaped movable contact piece 15: Fixed sheet 20, 20 ′: Liquid crystal display panel 20a: Display area 21: Liquid crystal cell 22, 22 ': Upper polarizing plate 23, 23': Lower polarizing plate 22s, 23s: Slit 30: Light guide sheet 30s, 30's: Light shielding layer 40: Light emitting diode (light source) LED)
211: Upper substrate (substrate) 212: Lower substrate (substrate)
213: Liquid crystal layer

Claims (6)

A switch sheet having a plurality of dome switches, and a liquid crystal display panel disposed on the switch sheet,
The liquid crystal display panel has a liquid crystal layer sandwiched between two flexible substrates, and includes polarizing plates on the outer surfaces of the two substrates that are not in contact with the liquid crystal layer, and the dome switch It has a function to display a virtual operation button for each corresponding display area,
An input device configured such that when each display area of the liquid crystal display panel is pressed from the viewing side, the dome switch corresponding to the switch sheet is pressed to perform a switch operation,
An input device, wherein a slit is formed in a portion corresponding to the periphery of each display region in at least one of each polarizing plate.   2. The input device according to claim 1, wherein the slit is formed at a position corresponding to a portion corresponding to the periphery of each of the display areas of both of the polarizing plates.   3. The input device according to claim 1, wherein the slit is formed endlessly or divided into a plurality of portions so as to surround a portion corresponding to each display area of the polarizing plate. . A switch sheet having a plurality of dome switches, and a liquid crystal display panel disposed on the switch sheet,
The liquid crystal display panel includes a flexible liquid crystal layer sandwiched between two flexible substrates, a pair of polarizing plates on the outer surfaces of the two substrates that are not in contact with the liquid crystal layer, and the dome. It has a function to display a virtual operation button for each display area corresponding to the switch,
An input device configured such that when each display area of the liquid crystal display panel is pressed from the viewing side, the dome switch corresponding to the switch sheet is pressed and switched.
At least one of the polarizing plates is provided only in a region corresponding to each display region.   5. The input device according to claim 4, wherein both the polarizing plates are provided so as to face each other only in regions corresponding to the display regions of the liquid crystal display panel.   6. The liquid crystal display panel according to claim 1, further comprising: a flexible light guide plate disposed on the switch sheet side of the liquid crystal display panel; and a light source that illuminates the light guide plate from an end surface. The input device according to one item.

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