Electronic device

Abstract

To provide an electronic device having a reinforcing plate with appropriate stiffness, and configured to properly detect pointed positions through an electromagnetic-induction position detection sensor mounted thereon.SOLUTION: An electronic device includes a reinforcing plate 22 arranged between a display element 21 and a position detection sensor 23 of electromagnetic induction type disposed on a back side of the display element 21. The reinforcing plate 22 includes a slit section corresponding to an entire surface of a display screen of the display element 21. The slit section has first-type slits extending in a vertical direction of the display screen and second-type slits extending in a horizontal direction, the slits being provided uniformly in a manner having substantially the same opening dimensions. Accordingly, stiffness can be maintained over the entire surface of the slit section of the reinforcing plate while allowing a uniform amount of signals to pass (transmitted) through the entire surface of the slit section.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an electronic device configured with a display device and a position detection sensor, such as a high-performance mobile phone terminal called a smartphone or a tablet PC (Personal Computer).

Background Art

[0002] So-called flexible display elements having flexibility, such as organic electroluminescence displays and electronic paper displays, have come to be used in various electronic devices such as high-performance phone terminals, tablet PCs, and electronic book readers. Since the flexible display element is flexible like paper and can be bent, it can be considered to be used as a display element of a foldable portable terminal called a foldable terminal.

[0003] In the case of a foldable portable terminal, since it cannot be folded, a hard protective member such as tempered glass cannot be disposed on the display screen of the display element. In this case, the overall strength of the portable terminal becomes insufficient, and there is a possibility of causing problems such as malfunction or breakage due to an impact applied to the display screen, for example. In order to solve such problems, it is conceivable to dispose a reinforcing plate formed of metal or the like on the back side of the flexible display element so as to be bendable.

[0004] It is conceivable to mount an electromagnetic induction type position detection sensor or a capacitance type position detection sensor on the foldable portable terminal. When performing drawing input such as a fine graphic, it is desirable to mount an electromagnetic induction type position detection sensor so that drawing input can be performed with an electromagnetic induction type position indicator (electronic pen). However, since the electromagnetic induction type position detection sensor is non-transparent, in the case of a foldable terminal using this, the electromagnetic induction type position detection sensor is disposed on the back side of the flexible display element.

[0005] In this case, if a reinforcing plate is placed between the flexible display element and the electromagnetic induction type position detection sensor, the detection of the indicated position becomes impossible. In the case of an electromagnetic induction type position detection sensor, it is necessary to mutually transmit and receive signals (magnetic fluxes) between the sensor and the position indicator (electronic pen). This is because the reinforcing plate inhibits the transmission and reception of magnetic fluxes. Therefore, it is conceivable to make slits (cuts) in the reinforcing plate as in the invention disclosed in Patent Document 1 described later.

[0006] In the invention disclosed in Patent Document 1, a grounding conductor layer (solid electrode) for stabilizing the signal of the capacitance type position detection sensor is provided between the upper capacitance type position detection sensor and the lower electromagnetic induction type position detection sensor. The conductor layer is formed by arranging a plurality of one slit extending in the lateral direction (left - right direction) of the operation surface in the longitudinal direction (up - down direction) of the operation surface. Thereby, the detection of the indicated position by the upper capacitance type position detection sensor can be performed well. Also, mutual signal transmission and reception become possible between the lower electromagnetic induction type position detection sensor and the electromagnetic induction type position indicator, and the detection of the indicated position through the lower electromagnetic induction type position detection sensor can also be performed well.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the case of the invention disclosed in Patent Document 1, as described above, the conductor layer is formed by arranging a plurality of slits extending in the vertical direction of the operation surface in a row with one slit extending in the lateral direction of the operation surface. For this reason, when there is a slit on the loop coil extending in the lateral direction of the position detection sensor of the electromagnetic induction method and when there is no slit, a difference occurs in the signal level transmitted and received, and it is considered that it may be difficult to detect an appropriate indication position. That is, in an apparatus that requires wide-range and highly accurate position detection in recent years, in the case of the invention disclosed in Patent Document 1, since the signal transmitted and received between the position detection sensor of the electromagnetic induction method and the position indicator of the electromagnetic induction method cannot be made uniform at any position on the operation surface, it cannot be applied.

[0009] In this case, for example, it is conceivable to provide a plurality of slits extending short in the vertical direction side by side in the lateral direction between the slits extending in the lateral direction of the conductor layer. This is to increase the area of the slit so that signals can be transmitted and received at the same level at any position on the operation surface. Therefore, it is also conceivable to increase the area of the slit in the same way for the reinforcing plate provided between the flexible display element and the position detection sensor of the electromagnetic induction method. However, if the area of the slit provided in the reinforcing plate is simply increased, the rigidity of the entire reinforcing plate is reduced, and the intended strength cannot be obtained.

[0010] In view of the above, an object of the present invention is to provide an electronic device capable of appropriately detecting an indication position through a mounted position detection sensor of an electromagnetic induction method while imparting appropriate strength using a reinforcing plate.

Means for Solving the Problems

[0011] To solve the above problems, a display element, a first position detection sensor of an electromagnetic induction method disposed on the back side of the display element, the first position detection sensor detecting a position indicated on the display screen of the display element during operation, A reinforcing plate that is interposed between the display element and the first position detection sensor and has a slit portion corresponding to the entire surface of the display screen, is provided, The slit portion has a first type of slit and a second type of slit. Each of the first type of slits extends in the vertical direction of the display screen, and each of the second type of slits extends in the horizontal direction of the display screen. The first type and the second type of slits are uniformly provided in a manner having substantially the same opening dimensions. An electronic device characterized by this is provided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Best Mode for Carrying Out the Invention

[0013] Hereinafter, with reference to the drawings, an embodiment of an electronic device according to the present invention will be described. The present invention is applicable to various electronic devices equipped with a display element and a position detection sensor of an electromagnetic induction method. However, the present invention is more preferably applied to a foldable portable terminal such as a foldable terminal. Therefore, hereinafter, the case where the electronic device according to the present invention is applied to a foldable portable terminal will be described as an example.

[0014] [Appearance of Portable Terminal 1, etc.] FIG. 1 is a diagram for explaining a foldable portable terminal (hereinafter simply referred to as a portable terminal) 1 configured by applying an embodiment of the electronic device of the present invention. FIG. 1(A) is a perspective view of the portable terminal 1 in an open state. FIG. 1(B) is a side view of the portable terminal 1 in an open state. FIG. 1(C) is a side view of the portable terminal 1 in a state of being folded in half. As shown in FIGS. 1(A) and 1(B), the portable terminal 1 has a first housing 11 and a second housing 12 connected by a hinge (hinge) provided in the cover portion 13. Thereby, as shown in FIG. 1(C), the portable terminal 1 can be folded in half so that the first housing 11 and the second housing 12 face each other.

[0015] The portable terminal 1 is provided with a flexible portion 2. The flexible portion 2 is configured by laminating an organic electroluminescence display such as an OLED (Organic Light-Emitting Diode) or a light-emitting polymer, a position detection sensor of an electromagnetic induction method, and the like. The organic electroluminescence display has flexibility and is a flexible display element that can be bent like paper. In addition, the position detection sensor of the electromagnetic induction method is configured using a flexible substrate, and its thickness is also as thin as, for example, about 12 μm (micrometer), so it can be bent like paper.

[0016] Therefore, when the mobile terminal 1 is in the open state, as shown in FIGS. 1(A) and 1(B), the flexible portion 2 forms a wide area where the upper surfaces of the first housing and the second housing that can be viewed by the user are combined, with a display screen on one side and a position detection area corresponding to this display screen. Also, when the mobile terminal 1 is in the closed state, as shown by the dotted line in FIG. 1(C), the flexible portion 2 is folded in half and located inside where the first housing and the second housing face each other, and can be made half the size when the mobile terminal 1 is in the open state.

[0017] As described above, since the mobile terminal 1 is foldable, a strengthened glass cannot be arranged on the display screen of the flexible display element. Of course, it is possible to arrange the strengthened glass separately on each of the upper surface side of the first housing 11 and the upper surface side of the second housing 12. However, in this case, a connection portion of the two strengthened glasses is formed at the boundary portion between the upper surface of the first housing 11 and the upper surface of the second housing 12, and a seamless one-sided display screen cannot be realized.

[0018] Therefore, in the mobile terminal 1 of this embodiment, a reinforcing plate is provided in the flexible portion 2 to maintain the high strength of the mobile terminal 1. However, there is a concern that the reinforcing plate may affect the detection of the indicated position through the electromagnetic induction type position detection sensor, and the indicated position may not be detected appropriately. Therefore, in the mobile terminal 1, by devising the reinforcing plate, the detection of the indicated position through the electromagnetic induction type position detection sensor can also be performed appropriately.

[0019] [Configuration Example of Flexible Portion 2] Figures 2 and 3 are diagrams for explaining the flexible portion 2 mounted on the mobile terminal 1. As shown in FIG. 2, the flexible portion 2 mounted on the mobile terminal 1 has a four-layer structure. Specifically, the topmost layer is the flexible display element 21, and a reinforcing plate 22 is provided on the back side of the flexible display element 21. An electromagnetic induction type position detection sensor (first position detection sensor) 23 is provided on the back side of the reinforcing plate 22, and a metal sheet 24 is provided on the back side of the position detection sensor 23. Thus, in this embodiment, the reinforcing plate 22 is provided between the flexible display element 21 and the electromagnetic induction type position detection sensor 23.

[0020] Taking an example, the thickness of each layer of the flexible portion 2 is as follows: as shown in FIG. 3, the flexible display element 21 is about 200 μm to 500 μm, the reinforcing plate 22 is about 150 μm, the position detection sensor 23 is about 12 μm, and the metal sheet 24 is about 100 μm. In this embodiment, on the side of the position detection sensor 23, the metal sheet 24 has a magnetic layer with a thickness of 50 μm, and a metal layer with a thickness of 50 μm is provided below it. Thereby, the magnetic flux generated by the electromagnetic induction type position detection sensor 23 passes through the magnetic layer without passing through the metal layer of the metal sheet 24 and heads toward the display element. Since the magnetic flux passing through the metal layer is small, the generation of eddy currents can be suppressed, and the magnetic flux can be prevented from being attenuated. In addition, the metal layer of the metal sheet 24 can prevent the magnetic flux generated by the position detection sensor 23 from reaching below the metal layer, and can prevent the influence of magnetism from the electronic circuit located below the metal sheet 24.

[0021] The reinforcing plate 22 is desirably formed of a material that can appropriately pass the magnetic flux and is unlikely to generate eddy currents so as not to have an electrical influence on the position detection sensor 23. That is, it is desired to be formed of a non-magnetic and low-conductivity material. Therefore, in this embodiment, the reinforcing plate 22 is formed of stainless steel. More specifically, the reinforcing plate 22 is formed of a stainless steel material with a JIS steel type number of SUS316.

[0022] Stainless steel materials with a JIS steel grade number of SUS316 have non-magnetic properties, making it difficult for magnetic poles to appear. They also have high electrical resistance and are difficult to generate eddy currents, and have high rigidity, so they are suitable for use in the reinforcing plate 22. Further, as shown in FIG. 3, since the reinforcing plate 22 has a thickness 1.5 times that of the metal sheet 24, the strength of the mobile terminal 1 can be increased. Note that the reinforcing plate 22 is not limited to being formed of a stainless steel material of SUS316. It is of course also possible to form it of other materials such as hard resin, which are non-magnetic and have low conductivity and have the desired rigidity.

[0023] Even if the reinforcing plate 22 is formed of a material having non-magnetic properties and high electrical resistance, it has a certain thickness. For this reason, it will hinder the transmission and reception of signals (magnetic fluxes) between the electromagnetic induction type position detection sensor 23 and an electromagnetic induction type electronic pen (position indicator) (not shown). If possible, it is desirable that magnetic fluxes pass uniformly at any position in the position detection area of the position detection sensor 23 between the electromagnetic induction type position detection sensor 23 and the electromagnetic induction type electronic pen. Therefore, slits are provided in the reinforcing plate 22. In this case, depending on the way the slits are provided, it is considered that the rigidity of the reinforcing plate 22 may be reduced and sufficient strength cannot be imparted to the mobile terminal 1.

[0024] Further, since the reinforcing plate 22 is provided on the back side of the flexible display element 21, the unevenness of the reinforcing plate 22 caused by the provision of the slits may cause display unevenness. Also, since the flexible display element 21 has the properties of being thin and flexible, it is considered that the unevenness of the slits formed in the reinforcing plate 22 disposed on the back side of the flexible display element 21 may affect the thickness of the drawn line. That is, it is considered that the thickness of the drawn line may not be uniform, and thin portions and thick portions may occur, resulting in a wavy line.

[0025] Therefore, when providing slits in the reinforcing plate 22, it is necessary to satisfy the following three conditions: (1) the magnetic flux passes uniformly at any position in the position detection area; (2) the desired rigidity can be maintained; and (3) no density difference is provided so that display unevenness or wavy drawing images do not occur. Also, as will be described later, the electromagnetic induction type position detection sensor 23 is configured by arranging a plurality of X-axis loop coils extending in the Y-axis direction (vertical direction) in the X-axis direction (horizontal direction) and arranging a plurality of Y-axis loop coils extending in the X-axis direction (horizontal direction) in the Y-axis direction (vertical direction). In this case, since the X-axis loop coils are composed of straight lines in the vertical direction and the Y-axis loop coils are composed of straight lines in the horizontal direction, it is necessary to consider the characteristics of the configuration of such an electromagnetic induction type position detection sensor.

[0026] Taking these factors into consideration, in this embodiment, slits extending in the vertical direction (Y-axis direction) of the display screen and slits extending in the horizontal direction (X-axis direction) of the display screen are uniformly provided in the reinforcing plate 22 without density difference so that the opening areas are substantially the same. Note that the display screen of the flexible display element 21, the slit area where the slits of the reinforcing plate 22 are provided, and the position detection area of the electromagnetic induction type position detection sensor are made to have substantially the same shape and area. Further, in the optimal case, when the slit area is slightly widened, the influence of the frame portion described later can be made smaller and the accuracy can be improved.

[0027] Thereby, the strength of the portable terminal 1 can be increased by the reinforcing plate 22 in which slits are formed so as to maintain rigidity over the entire display screen of the flexible display element 21. Moreover, in the reinforcing plate 22, slits extending in the vertical direction of the display screen and slits extending in the horizontal direction of the display screen are uniformly provided without density difference so that the opening areas are substantially the same. For this reason, the unevenness caused by forming the slits is not conspicuous, and moreover, it can be appropriately performed without disturbing the transmission and reception of magnetic flux.

[0028] [Configuration Example of Reinforcing Plate 22] FIG. 4 is a diagram for explaining a reinforcing plate 22 of a flexible portion 2 mounted on the mobile terminal 1. FIGS. 4(A) and 4(B) each show an H-shaped slit formed by connecting the midpoints of two parallel bar-shaped slits of the same length with a single bar-shaped slit, and the slit areas are formed by arranging such H-shaped slits in the vertical and horizontal directions respectively. In the examples shown in FIGS. 4(A) and 4(B), the width of a single bar-shaped slit (the width in the direction intersecting the longitudinal direction) is 0.5 mm.

[0029] Also, as shown by blackening the upper left end side of FIG. 4(A), FIG. 4(A) shows a reinforcing plate 22 with a slit area formed using three types of H-shaped slits with different lengths of a single bar-shaped slit connecting the midpoints of two parallel bar-shaped slits of the same length. FIG. 4(B) shows a reinforcing plate 22 with a slit area formed using one type of H-shaped slit with a common length of a single bar-shaped slit connecting the midpoints of two parallel bar-shaped slits of the same length, as shown by blackening the upper left end side of FIG. 4(B).

[0030] In the examples of FIGS. 4(A) and 4(B), the H-shaped slits are arranged alternately in the vertical and horizontal directions such that a slit with two slits of the same length positioned horizontally and a slit with two slits of the same length positioned vertically are provided. In the examples of FIGS. 4(A) and 4(B), slits can be uniformly provided in the slit area of the reinforcing plate 22 without any gaps. That is, the opening area of the slits extending in the vertical direction and the opening area of the slits extending in the horizontal direction are made to be approximately equal within the slit area. Therefore, the metal portions without slits in the slit area are also made to be uniformly distributed within the slit area.

[0031] Thus, even if a slit is provided in the reinforcing plate 22, the overall rigidity of the reinforcing plate 22 will not be deteriorated. Moreover, since the H-shaped slits can be uniformly provided over the entire surface of the slit area without density differences, unevenness will not occur on the display screen, and display unevenness will not occur, nor will the drawn lines undulate. Of course, the uniformly provided H-shaped slits allow magnetic flux to penetrate, and further suppress the generation of eddy currents due to the magnetic flux passing through the reinforcing plate 22, making it possible to appropriately perform magnetic flux transmission and reception without disturbing it.

[0032] Note that the difference between FIGS. 4(A) and 4(B) lies in the magnetic flux coupling rate (coupling ratio). When the coupling rate of the magnetic flux between the position detection sensor 23 and the position indicator is 100% in the case where there is no reinforcing plate 22, the coupling rate in the case of FIG. 4(A) is 89.1%, while the coupling rate in the case of FIG. 4(B) is 88.1%. Experiments have verified that the coupling rate improves when slits of different lengths are used.

[0033] [Configuration of the bent portion of the reinforcing plate] FIG. 5 is a diagram for explaining the bent portion of the reinforcing plate 22 of the flexible portion 2 mounted on the mobile terminal 1. When slits are provided on the entire surface of the reinforcing plate 22 in the manner shown in FIGS. 4(A) and 4(B), the mobile terminal 1 cannot be smoothly folded as shown in FIG. 1(C). Since there is a metal portion extending in a direction intersecting the bent portion at the bent portion, it is difficult to bend and is also easily damaged.

[0034] Therefore, as shown in FIG. 5(A), a bent portion 22C is provided in the central portion of the reinforcing plate 22, with the left side being the left slit portion 22L and the right side being the right slit portion 22R. The left slit portion 22L and the right slit portion 22R are each provided with H-shaped slits uniformly without gaps in the manner shown in FIG. 4(A) or FIG. 4(B) over their entire surfaces. Further, as shown in FIG. 5(B), the bent portion 22C is a portion formed in a mesh shape so as to have a plurality of substantially diamond-shaped openings. By forming the bent portion 22C in a mesh shape in this way, the bent portion 22C can be slightly extended in the directions indicated by arrow a and arrow b, and the portion of the bent portion 22C can be bent (folded in half) without difficulty.

[0035] Also, as shown in FIG. 5, a frame portion 22FL where basically no slits are provided is provided around the reinforcing plate 22. The inside of this frame portion 22FL is the slit area, corresponding to the display screen of the flexible display element and also corresponding to the position detection area of the electromagnetic induction type position detection sensor. Therefore, the frame portion does not overlap with the display screen or the position detection area. Also, basically no slits are provided in the frame portion 22FL. To prevent the disturbance of the magnetic flux by the frame portion 22FL, if the slit area is made the same as or slightly wider than the position detection area, the accuracy of position indication will be further improved even at the edge of the display screen.

[0036] Note that slits may be provided in a mesh shape at the upper end portion and the lower end portion of the bent portion 22C in the same manner as the other portions of the bent portion 22C. This is to enable the smooth folding and opening operations of the mobile terminal 1. Also, for the left slit portion 22L and the right slit portion 22R as well, it is conceivable to provide slits in a mesh shape in the same manner as the bent portion 22C. However, in the case of the mesh-shaped slits (FIG. 5(B)) and the H-shaped slits (FIG. 4(A), (B)), the rigidity can be maintained higher when the H-shaped slits are provided.

[0037] Further, the bent portion 22C may be provided with an I-shaped slit similar to the letter I of the alphabet along the fold line. That is, a plurality of slits extending along the fold line may be provided in the bent portion 22C to form the bent portion 22C. In this case, a smooth bend is possible without forming a metal portion extending in a direction intersecting the fold line.

[0038] Further, since the shapes of the slits are different between the left slit portion 22L and the right slit portion 22R and the bent portion 22C, the magnetic flux coupling rate is different, which may lead to an incorrect detection of the indicated position at the bent portion 22C. Therefore, as will be described later, the detection output of the position detection sensor 23 at the bent portion 22C is corrected. Thereby, the indicated position can be detected in the same manner as in the areas corresponding to the left slit portion 22L and the right slit portion 22R provided with the H-shaped slits.

[0039] [Configuration Example of Position Detection Device Using Electromagnetic Induction Method] FIG. 6 is a block diagram for explaining a configuration example of a position detection device including a position detection sensor 23 using an electromagnetic induction method. The electronic pen 300 uses an electromagnetic induction method and includes a resonance circuit configured by connecting a coil L for signal transmission and reception, a pen pressure detection unit Cv which is a variable capacitance capacitor, a resonance capacitor Cf, etc. in parallel as shown in the upper left of FIG. 6.

[0040] The position detection device 100 includes a position detection sensor 23 formed by laminating an X-axis direction loop coil group 23X and a Y-axis direction loop coil group 23Y. The loop coils X of the X-axis loop coil group 23X 1 , X 2 , …, X 40 and the loop coils Y of the Y-axis loop coil group 23Y 1 , Y 2 , …, Y 30Each of them may be in one turn or in multiple turns of two or more turns. As described above, such a position detection sensor 23 is disposed below a reinforcing plate 22 disposed on the back side of the flexible display element 21. By connecting this position detection sensor 23 to the position detection circuit 101, the position detection device 100 is configured as a whole.

[0041] The position detection circuit 101 is disposed inside the first housing 11 or the second housing 12 below the metal sheet 24. The position detection circuit 101 includes an oscillator 102, a current driver 103, a selection circuit 104, a switching connection circuit 105, a receiving amplifier 106, a position detection circuit 107, a pen pressure detection circuit 108, and a processing control unit 109. As shown in FIG. 6, the X-axis direction loop coil group 23X and the Y-axis direction loop coil group 23Y of the position detection sensor 23 are connected to the selection circuit 104. The selection circuit 104 sequentially selects one of the two loop coil groups 23X and 23Y according to the control of the processing control unit 109.

[0042] The processing control unit 109 is constituted by a microprocessor. The processing control unit 109 controls the selection of the loop coil in the selection circuit 104 and the switching of the switching connection circuit 105, and also controls the processing timing in the position detection circuit 107 and the pen pressure detection circuit 108.

[0043] The oscillator 102 generates an AC signal with a frequency f0. The oscillator 102 supplies the generated AC signal to the current driver 103 and the pen pressure detection circuit 108. The current driver 103 converts the AC signal supplied from the oscillator 102 into a current and sends it to the switching connection circuit 105. The switching connection circuit 105 switches the connection destination (transmission side terminal T, reception side terminal R) to which the loop coil selected by the selection circuit 104 is connected according to the control from the processing control unit 109. Among these connection destinations, the current driver 103 is connected to the transmission side terminal T, and the receiving amplifier 106 is connected to the reception side terminal R, respectively.

[0044] The switching connection circuit 105 is switched to the transmission-side terminal T during the transmission period and to the reception-side terminal R during the reception period. Thereby, during the transmission period, the loop coil that receives the current supply from the current driver 103 through the transmission-side terminal T generates a magnetic field, transmits it to the electronic pen 300, and acts on the resonance circuit of the electronic pen 300. In this case, the resonance circuit of the electronic pen 300 generates a position indication signal (radio wave) and transmits it to the position detection sensor 23 side.

[0045] On the other hand, during the reception period, the loop coil selected by the selection circuit 104 is connected to the reception amplifier 106 through the reception-side terminal R. When the loop coil is under the action of the magnetic field from the electronic pen 300, an induced voltage is generated in the loop coil, and this induced voltage is sent to the reception amplifier 106 through the selection circuit 104 and the switching connection circuit 105. The reception amplifier 106 amplifies the induced voltage supplied from the loop coil and sends it to the position detection circuit 107 and the pen pressure detection circuit 108.

[0046] That is, an induced voltage is generated in each loop coil of the X-axis direction loop coil group 23X and the Y-axis direction loop coil group 23Y by the radio wave transmitted from the electronic pen 300. For this reason, the position detection circuit 107 detects the induced voltage (reception signal) generated in the loop coil, converts the detected output signal into a digital signal, and outputs it to the processing control unit 109. The processing control unit 109 calculates the coordinate values of the indicated positions in the X-axis direction and the Y-axis direction of the electronic pen 300 based on the digital signal from the position detection circuit 107, that is, the level of the voltage value of the induced voltage generated in each loop coil.

[0047] On the one hand, the pen pressure detection circuit 108 synchronously detects the output signal of the receiving amplifier 106 with the AC signal from the oscillator 102 to obtain a signal with a level corresponding to the phase difference (frequency deviation) between them. In this case, the signal corresponding to the phase difference (frequency deviation) is converted into a digital signal and output to the processing control unit 109. The processing control unit 109 detects the pen pressure applied to the electronic pen 300 based on the digital signal from the pen pressure detection circuit 108, that is, the level of the signal corresponding to the phase difference (frequency deviation) between the transmitted radio wave and the received radio wave.

[0048] Note that, as described above, for the output signals from the loop coils in the portions corresponding to the bent portions 22C of the reinforcing plate 22 located on the upper surface side of the position detection sensor 23, the position detection circuit 107 and the pen pressure detection circuit 108 perform correction. As a result, even in the portion of the position detection sensor 23 corresponding to the bent portion 22C, the detection of the indicated position can be performed by making the conditions the same as those in the other portions provided with the H-shaped slits. Therefore, even when an instruction is made on the bent portion 22C, the indicated position and the pen pressure can be appropriately detected.

[0049] In this way, the position detection circuit 101 switches between the signal transmission period and the reception period. During the transmission period, it supplies driving power to the electronic pen 300 to drive it, and during the reception period, it receives the signal from the electronic pen 300 to detect the indicated position and the pen pressure. This position detection circuit 101 is configured as a circuit board. Thereby, by connecting the cable portion of the position detection sensor 23 to the position detection circuit 101 configured as the circuit board, the position detection device 100 can be realized and mounted on the mobile terminal 1 as an input device.

[0050] As described above, the mobile terminal 1 of this embodiment is provided with a reinforcing plate 22 between the flexible display element 21 and the position detection sensor 23 of the electromagnetic induction method. However, although the reinforcing plate is formed of, for example, SUS316 stainless steel, the portion corresponding to the display screen of the flexible display element 21 and the position detection area of the position detection sensor 23 is a slit area provided with slits uniformly. Thereby, in the mobile terminal 1, it is possible to maintain the rigidity of the reinforcing plate 22 and impart strength, and at the same time, no display unevenness is generated on the display screen, and signals can be appropriately transmitted and received between the position detection sensor 23 of the electromagnetic induction method and the electronic pen 300 of the electromagnetic induction method. Of course, it is also possible to easily fold and open the mobile terminal 1.

[0051] [Another Example of the Flexible Portion] The flexible portion 2 of the mobile terminal 1 of the above-described embodiment included the position detection sensor 23 of the electromagnetic induction method. However, in addition to the position detection sensor 23 of the electromagnetic induction method, a capacitance-type position detection sensor can be further provided. Thereby, for example, a hybrid mobile terminal 1 capable of both instruction input using a user's finger or a so-called electrostatic pen and instruction input using an electromagnetic induction type electronic pen can be realized.

[0052] FIGS. 7 and 8 are diagrams for explaining the flexible portion 2A mounted on the mobile terminal 1A. In the flexible portion 2A shown in FIGS. 7 and 8, the portions having the same configuration as the portions constituting the flexible portion 2 shown in FIGS. 2 and 3 are denoted by the same reference numerals, and detailed description of those portions is omitted because of duplication. In FIGS. 7 and 8, since the capacitance-type position detection sensor (second position detection sensor) 25 can be configured transparently using thin linear electrodes, it can be disposed on the upper surface side of the flexible display element 21. That is, as shown in FIG. 7, the flexible portion 2A can be formed by laminating in order from above: the capacitance-type position detection sensor 25 → the flexible display element 21 → the reinforcing plate 22 → the electromagnetic induction-type position detection sensor 23 → the metal sheet 24.

[0053] Therefore, as shown in FIG. 8, a flexible portion 2A can be configured by disposing a capacitance-type position detection sensor 25, which is thinner and more transparent than the electromagnetic induction-type position detection sensor 23, on the upper surface side of the flexible display element 21. Also in this case, as shown in FIGS. 7 and 8, a reinforcing plate 22 is provided between the flexible display element 21 and the electromagnetic coupling-type position detection sensor 23. As described above, this reinforcing plate 22 is non-magnetic and has a high electrical resistance, so it is difficult for eddy currents to occur.

[0054] Therefore, even if there is an electromagnetic induction-type position detection sensor 23 that generates an alternating magnetic field, which is a magnetic field whose magnitude and direction change repeatedly over time, it is difficult for eddy currents to occur in the reinforcing plate 22. For this reason, it does not affect the detection of the indicated position through the capacitance-type position detection sensor 25. That is, a mobile terminal 1A can be configured that can satisfactorily detect both the indicated position through the capacitance-type position detection sensor 25 and the indicated position using the electromagnetic induction-type position detection sensor 23. Moreover, due to the presence of the reinforcing plate 22, the strength can be increased over the entire upper surface side of the mobile terminal 1 where the display screen of the flexible display element 21 is present, so a mobile terminal 1 with high strength can be realized even when it is open.

[0055] [Configuration Example of Capacitance-Type Position Detection Device] FIG. 9 is a diagram for explaining a configuration example of a capacitance-type position detection device 200 mounted on the mobile terminal 1A. As shown in FIG. 9, the position detection device 200 includes a position detection sensor 25 and a position detection circuit 210 connected to the position detection sensor 25.

[0056] The position detection sensor 25 is formed by laminating a first conductor group 251 and a second conductor group 252. The first conductor group 251, for example, includes a plurality of first conductors 25Y 1 ~25Y m arranged in parallel at a predetermined interval in the Y-axis direction. The second conductor group 252 includes a plurality of second conductors 25X extending in a direction intersecting the first conductors, in this example, in the vertical direction (Y-axis direction) perpendicular to the first conductors. 1~25X n They are arranged in parallel at a predetermined interval from each other and disposed in the X-axis direction.

[0057] Thus, in the position detection sensor 25 of the position detection device 200, a configuration is provided in which the position indicated by the user's finger or a capacitive electronic pen (electrostatic pen) is detected using a sensor pattern formed by crossing the first conductor group 251 and the second conductor group 252. In the description of FIG. 9, when indicating one of the first conductors 25Y 1 ~25Y m it is described as the first conductor 25Y, and when indicating one of the second conductors 25X 1 ~25X n it is described as the second conductor 25X.

[0058] The position detection circuit 210 includes a selection circuit 211 that serves as an input / output interface with the position detection sensor 25, an amplification circuit 212, a received signal processing circuit 213, and a control circuit 214. The received signal processing circuit 213 includes, although not shown, a band-pass filter, a detection circuit, a sample-and-hold circuit, and an AD (Analog to Digital) conversion circuit, etc.

[0059] The selection circuit 211 selects one conductor 25Y or 25X from among the first conductor group 251 and the second conductor group 252 based on a control signal from the control circuit 214. The conductor selected by the selection circuit 211 is connected to the amplification circuit 212, and a signal corresponding to the potential change due to the contact of the user's finger or electrostatic pen is detected by the selected conductor and amplified by the amplification circuit 212. The output of this amplification circuit 212 is supplied to the received signal processing circuit 213. In the received signal processing circuit 213, the supplied signal is band-limited, detection-processed, then sample-held, converted into a digital signal, and supplied to the control circuit 214.

[0060] The control circuit 214 supplies a control signal to the selection circuit 211 for control according to a program stored in an internal ROM (Read Only Memory), and also supplies a control signal to the reception signal processing circuit 213 for control. Further, the control circuit 214 calculates the position coordinates on the position detection sensor 25 indicated by the user's finger or an electrostatic pen from the digital data from the reception signal processing circuit 213. When using a so-called active electrostatic pen that sends a position indication signal or a pen pressure signal, the control circuit 214 can also perform a process of detecting the pen pressure detected by the pen pressure detection unit of the active electrostatic pen from the digital data from the reception signal processing circuit 213.

[0061] In this way, the position detection device 200 is enabled to detect the indicated position by the user's finger or an electrostatic pen, and supply this, for example, to a computer device to execute processing corresponding to an icon at the indicated position. In the case of the mobile terminal 1A on which both such a capacitance type position detection device 200 and the electromagnetic induction type position detection device 100 described with reference to FIG. 6 are mounted, these can be used properly. That is, simple operations can be performed by the user's finger or the like, and an indication input can be received by the capacitance type position detection device 200. Further, when detailed drawing is desired to be performed, it can be performed using the electromagnetic induction type electronic pen 300, and an indication input can be received by the electromagnetic induction type position detection device 100.

[0062] Also, even when both the capacitance type position detection sensor 25 and the electromagnetic induction type position detection sensor 23 are mounted, since the reinforcing plate 22 is provided, the rigidity of the reinforcing plate 22 can be maintained to impart strength. At the same time, signal transmission and reception between the electromagnetic induction type position detection sensor 23 and the electromagnetic induction type electronic pen 300 can be properly performed without generating display unevenness or waviness of a drawn line on the display screen. Of course, it is also possible to easily fold or open the mobile terminal 1. Further, detection of the indicated position through the capacitance type position detection sensor 25 can be properly performed without being affected by the electromagnetic induction type position detection sensor 23.

[0063] [Effects of the Embodiment] According to the mobile terminal 1 of the above-described embodiment, by providing the reinforcing plate 22 between the flexible display element 21 and the electromagnetic induction type position detection sensor 23, it is possible to impart to the mobile terminal 1 the strength corresponding to the rigidity of the reinforcing plate 22. Moreover, on the entire surface of the slit area of the reinforcing plate 22, slits extending in the vertical direction of the display screen and slits extending in the horizontal direction are uniformly provided so that the opening areas are substantially the same. Thereby, without causing display unevenness, regarding the transmission and reception of magnetic flux, it can be appropriately performed at any position in the slit area without obstructing the transmission and reception of magnetic flux. Further, in the case of the mobile terminal 1A described above, even if the capacitance type position detection sensor 25 is arranged on the upper surface side of the flexible display element 21, it is not affected by the electromagnetic induction type position detection sensor 23 due to the action of the reinforcing plate 22. Therefore, the detection of the instructed position through the capacitance type position detection sensor 25 can be appropriately performed.

[0064] [Modifications, etc.] FIG. 10 is a diagram for explaining the shape pattern of the slit provided in the slit portion of the reinforcing plate. In the above-described embodiment, as shown in FIG. 10(A), by connecting the midpoints of two parallel slits of the same length with one slit, an H-shaped slit similar in shape to the alphabet letter H is used. However, it is not limited to this.

[0065] For example, as shown in FIG. 10(B), one bar-shaped I-shaped slit similar to the alphabet letter I may be uniformly arranged in the slit area of the reinforcing plate 22 without density variation while changing the arrangement direction. Further, as shown in FIG. 10(C), a T-shaped slit composed of a horizontal bar and a vertical bar similar to the alphabet letter T may be uniformly arranged in the slit area of the reinforcing plate 22 without density variation. Further, as shown in FIG. 10(D), a Z-shaped slit composed of two horizontal bars and an oblique bar connecting them similar to the alphabet letter Z may be uniformly arranged in the slit area of the reinforcing plate 22 without density variation.

[0066] Further, for example, slits having different shapes (forms) such as a combination of an H-shaped slit and an I-shaped slit, or a combination of an H-shaped slit and a T-shaped slit may be combined to form slits in the slit area of the reinforcing plate 22. In addition to this, the shape of the slit provided in the slit area of the reinforcing plate 22 can be various. What is important in this case is (1) not to deteriorate the rigidity of the reinforcing plate 22. (2) Not to cause unevenness on the display screen of the flexible display element 21, such as an increase in the interval between the slits, and not to cause display unevenness or the like. (3) To enable the same uniform transmission and reception of magnetic flux at any position in the position detection area of the position detection sensor 23 between the electromagnetic induction type position detection sensor 23 and the electromagnetic induction type electronic pen 300. It is sufficient to satisfy all of these.

[0067] Also, in the above-described embodiment, in order to realize the foldable mobile terminal 1, the flexible display element 21 is used. The flexible display element 21 is not limited to an organic electroluminescence display such as an OLED or a light-emitting polymer. Of course, a display element called electronic paper may be used. Electronic paper is a display medium that maintains the visibility and portability that are the advantages of paper and can be electrically rewritten with the display content. The structure of the electronic paper is, simply, a display in which a large number of minute spheres, each of which has one hemisphere painted white and the other hemisphere painted black, are embedded in the display. A part of the spheres is charged with static electricity, and black characters can be made to float on a white background by rotating the spheres by an electric field. In recent years, there are also those that can display in color.

[0068] Further, the display element is not limited to a flexible display element, and may be a so-called panel display such as an LCD (Liquid Crystal Display) or a plasma display. However, by using the present invention, when using a flexible display element such as an OLED or an electronic paper as the display element, the strength can be added to the portable terminal without using strengthened glass. Therefore, this invention is more suitable for use when forming a so-called foldable terminal using a flexible display element.

Explanation of Signs

[0069] 1, 1A... Portable terminal, 11... First housing, 12... Second housing, 13... Cover portion, 2, 2A... Flexible portion, 21... Flexible display element, 22... Reinforcing plate, 22L... Left slit portion, 22R... Right slit portion, 22C... Bending portion, 22FL... Frame portion, 23... Electromagnetic induction type position detection sensor, 24... Metal sheet, 25... Capacitance type position detection sensor, 100... Electromagnetic induction type position detection device, 200... Capacitance type position detection device, 300... Electromagnetic induction type electronic pen

Claims

1. A display element; a first position detection sensor of an electromagnetic induction type disposed on a rear side of the display element, the first position detection sensor detecting a position pointed to on a display screen of the display element during operation; a reinforcing plate interposed between the display element and the first position detection sensor and having a slit portion corresponding to the entire surface of the display screen; Equipped with the slit portion has a first type slit and a second type slit, each of the first type slits extends in a vertical direction of a display screen, each of the second type slits extends in a horizontal direction of the display screen, and the first type slits and the second type slits are uniformly provided in a manner having substantially the same opening size; 1. An electronic device comprising:

2. 2. The electronic device according to claim 1, A frame portion without slits is provided on the outer edge of the reinforcing plate.

1. An electronic device comprising:

3. 2. The electronic device according to claim 1, A frame portion having no slits is provided on the outer edge of the reinforcing plate, The frame portion does not overlap the display screen of the display element.

1. An electronic device comprising:

4. 2. The electronic device according to claim 1, The display screen of the display element, the position detection area of ​​the first position detection sensor, and the slit area of ​​the reinforcing plate where the slits are provided are substantially identical in shape and area, and are laminated so as to overlap each other.

1. An electronic device comprising:

5. 2. The electronic device according to claim 1, The reinforcing plate is made of a non-magnetic material.

1. An electronic device comprising:

6. 2. The electronic device according to claim 1, The reinforcing plate is made of stainless steel.

1. An electronic device comprising:

7. 2. The electronic device according to claim 1, The reinforcing plate is made of stainless steel having a JIS steel grade number of SUS316.

1. An electronic device comprising:

8. 2. The electronic device according to claim 1, the display element and the first position detection sensor are bendable, The reinforcing plate includes a folding portion having a foldable slit at a position where the display element and the first position detection sensor are folded, and is configured to be foldable.

1. An electronic device comprising:

9. 2. The electronic device according to claim 1, the display element and the first position detection sensor are bendable, The reinforcing plate is configured to be foldable, and includes a bending portion having a rod-shaped I-shaped slit along an axis of bending at a position where the display element and the first position detection sensor are bent.

1. An electronic device comprising:

10. 2. The electronic device according to claim 1, The slits in the reinforcing plate are provided in any one of the following shapes: a rod-shaped I-shape, a T-shape consisting of a horizontal bar and a vertical bar, a Z-shape consisting of two horizontal bars and a diagonal bar connecting them, and an H-shape consisting of two vertical bars and a horizontal bar connecting them.

1. An electronic device comprising:

11. 2. The electronic device according to claim 1, the display element and the first position detection sensor are bendable, the reinforcing plate is configured to be foldable by including a folding portion having a foldable slit at a position where the display element and the first position detection sensor are folded; By correcting the detection output of the portion of the position detection sensor located below the bent portion of the reinforcing plate, it is possible to detect the indicated position on the bent portion.

1. An electronic device comprising:

12. 2. The electronic device according to claim 1, The display element is composed of any one of a liquid crystal display, an organic electroluminescence display, and an electronic paper display.

1. An electronic device comprising:

13. 2. The electronic device according to claim 1, A second position detection sensor of a capacitance type is provided on the front surface side of the display element to detect a pointed position on a display screen of the display element.

1. An electronic device comprising:

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