Electronic device

Abstract

Provided is an electronic device that adds appropriate strength using a reinforcement plate, and is capable of appropriately detecting a specified position through an electromagnetic induction type position detection sensor mounted thereon. A reinforcement plate (22) is disposed between a display element (21) and an electromagnetic induction type position detection sensor (23) which is mounted on the back side of the display element (21). The reinforcement plate (22) has a slit part corresponding to the entire surface of a display screen of the display element (21). In this slit part, a slit extending in a longitudinal direction of the display screen, and a slit extending in a horizontal direction thereof are arranged equally to have a substantially equal aperture area. Thus, uniform rigidity is maintained over the entire surface of the slit part of the reinforcement plate (22), and the amount of a signal that passes (is transmitted) through becomes uniform over the entire surface of the slit part.

Description

[Technical field]

[0001] The present invention relates to electronic devices including a display device and a position detection sensor, such as highly functional mobile phone terminals known as smartphones and tablet PCs (Personal Computers). [Background technology]

[0002] Flexible display elements, such as organic electroluminescence displays and electronic paper displays, are becoming more widely used in various electronic devices, such as high-performance telephone terminals, tablet PCs, and electronic book readers. Flexible display elements are flexible like paper and can be folded, so they can be used as display elements for folding mobile terminals, such as foldable terminals.

[0003] In the case of a foldable mobile terminal, since it cannot be folded, a hard protective member such as reinforced glass cannot be placed on the display screen of the display element. In this case, the overall strength of the mobile terminal is insufficient, and there is a possibility that problems such as failure or damage may occur due to, for example, an impact applied to the display screen. In order to solve such problems, it is conceivable to place a reinforcing plate made of metal or the like on the back side of the flexible display element so that it can be bent.

[0004] Foldable mobile terminals can be equipped with electromagnetic induction position detection sensors or capacitive position detection sensors. When drawing and inputting detailed shapes, it is desirable to have an electromagnetic induction position detection sensor and to be able to use an electromagnetic induction position indicator (electronic pen) to perform drawing input. However, because electromagnetic induction position detection sensors are non-transparent, in the case of foldable terminals using them, the electromagnetic induction position detection sensor will be placed 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 indicated position cannot be detected. In the case of an electromagnetic induction type position detection sensor, signals (magnetic flux) must be transmitted between the sensor and the position indicator (electronic pen), but the reinforcing plate blocks the transmission and reception of magnetic flux. Therefore, it is conceivable to make a slit (notch) in the reinforcing plate, as in the invention disclosed in Patent Document 1 described below.

[0006] In the invention disclosed in Patent Document 1, a grounding conductor layer (solid electrode) is provided between the capacitive position detection sensor in the upper layer and the electromagnetic induction position detection sensor in the lower layer to stabilize the signal of the capacitive position detection sensor. The conductor layer is formed by forming a single slit extending in the horizontal direction (left-right direction) of the operation surface, and arranging a plurality of slits in the vertical direction (up-down direction) of the operation surface. This allows the capacitive position detection sensor in the upper layer to detect the indicated position satisfactorily. In addition, signals can be transmitted and received between the electromagnetic induction position detection sensor in the lower layer and the electromagnetic induction position indicator, and the indicated position can also be detected satisfactorily through the electromagnetic induction position detection sensor in the lower layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2007-157107 A Summary of the Invention [Problem 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 single slit extending in the horizontal direction of the operation surface in a plurality of slits in the vertical direction of the operation surface. Therefore, it is considered that a difference occurs in the level of the signal transmitted and received between the case where there is a slit on the loop coil extending in the horizontal direction of the electromagnetic induction type position detection sensor and the case where there is no slit, and it may be difficult to detect the appropriate indicated position. In other words, in the case of the invention disclosed in Patent Document 1, it is not possible to make the signal transmitted and received between the electromagnetic induction type position detection sensor and the electromagnetic induction type position indicator uniform at any position on the operation surface, and therefore it is not applicable to recent devices that require high-precision position detection over a wide range.

[0009] In this case, for example, it is conceivable to arrange a plurality of short slits extending vertically between the slits extending horizontally of the conductor layer. This is to increase the area of ​​the slits and enable the same level of signal transmission and reception at any position on the operation surface. Therefore, it is conceivable to similarly increase the area of ​​the slits in the reinforcing plate provided between the flexible display element and the electromagnetic induction type position detection sensor. However, simply increasing the area of ​​the slits provided in the reinforcing plate reduces the rigidity of the entire reinforcing plate, making it impossible to obtain the desired strength.

[0010] In view of the above, an object of the present invention is to provide an electronic device that can properly detect an indicated position through an electromagnetic induction type position detection sensor mounted thereon while providing appropriate strength using a reinforcing plate. [Means for solving the problem]

[0011] In order to solve the above problems, A display element; a first position detection sensor of an electromagnetic induction type disposed on a rear side of the display element and configured to detect a pointed position on a display screen of the display element; a reinforcing plate disposed between the display element and the first position detection sensor, the reinforcing plate having a slit portion corresponding to the entire surface of the display screen, the slit portion having slits extending in the vertical direction of the display screen and slits extending in the horizontal direction of the display screen uniformly provided so that the opening areas are substantially the same; An electronic device comprising:

[0012] According to this electronic device, a reinforcing plate is disposed between the display element and a first electromagnetic induction type position detection sensor disposed on the back side of the display element. The reinforcing plate has a slit portion corresponding to the entire surface of the display screen of the display element, and in the slit portion, 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 approximately the same. This maintains the rigidity uniformly over the entire surface of the slit portion of the reinforcing plate, and also makes the amount of signal passing (transmitting) uniform over the entire surface of the slit portion. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram for explaining a mobile terminal configured to apply an embodiment of an electronic device of the present invention; [Diagram 2] 1A to 1C are diagrams for explaining a flexible section mounted on a mobile terminal according to an embodiment. [Diagram 3] 1A to 1C are diagrams for explaining a flexible section mounted on a mobile terminal according to an embodiment. [Figure 4] 11A and 11B are diagrams for explaining a reinforcing plate of a flexible part of the mobile terminal according to the embodiment. [Diagram 5] 11A and 11B are diagrams illustrating a bent portion of a reinforcing plate of a flexible portion of the mobile terminal according to the embodiment. [Figure 6] FIG. 1 is a block diagram for explaining a configuration example of an electromagnetic induction type position detection device. [Figure 7] 11A to 11C are diagrams illustrating another example of a flexible part mounted on the mobile terminal of the embodiment. [Figure 8]8A to 8C are diagrams for explaining a configuration example of the flexible section shown in FIG. 7. [Figure 9] FIG. 1 is a diagram for explaining a configuration example of a capacitive position detection device. [Figure 10] 11A to 11C are diagrams for explaining the shape pattern of slits provided in the slit portion of the reinforcing plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of an electronic device according to the present invention will be described with reference to the drawings. This invention is applicable to various electronic devices equipped with a display element and an electromagnetic induction type position detection sensor. However, this invention is more suitable for application to a folding type mobile terminal, such as a foldable terminal. Therefore, in the following, an example will be described in which the electronic device according to the present invention is applied to a folding type mobile terminal.

[0015] [Appearance of mobile device 1] FIG. 1 is a diagram for explaining a folding mobile terminal (hereinafter, simply referred to as a mobile terminal) 1 configured to apply an embodiment of an electronic device of the present invention. FIG. 1(A) is a perspective view of the mobile terminal 1 in an open state. FIG. 1(B) is a side view of the mobile terminal 1 in an open state. FIG. 1(C) is a side view of the mobile terminal 1 folded in half. As shown in FIGS. 1(A) and 1(B), the mobile terminal 1 has a first housing 11 and a second housing 12 connected by a hinge provided in the cover portion 13. As a result, the mobile terminal 1 can be folded in half with the first housing 11 and the second housing 12 facing each other as shown in FIG. 1(C).

[0016] The mobile terminal 1 is provided with a flexible section 2. The flexible section 2 is configured by laminating an organic electroluminescence display such as an OLED (Organic Light-Emitting Diode) or a light-emitting polymer, an electromagnetic induction type position detection sensor, and the like. The organic electroluminescence display is a flexible display element that is flexible and can be bent like paper. The electromagnetic induction type position detection sensor is configured using a flexible substrate, and has a thin thickness of, for example, about 12 μm (micrometers), so that it can be bent like paper.

[0017] Therefore, when the mobile terminal 1 is in an open state, the flexible part 2 forms one display screen over a wide area that is the combined upper surfaces of the first and second housings that can be viewed by the user, and a position detection area corresponding to this display screen, as shown in Figures 1(A) and (B). When the mobile terminal 1 is in a closed state, the flexible part 2 is folded in two as shown by the dotted line in Figure 1(C) and is positioned on the inside where the first and second housings face each other, so that the size of the mobile terminal 1 can be reduced to half of that when it is in an open state.

[0018] In this way, since the mobile terminal 1 is foldable, tempered glass cannot be placed on the display screen of the flexible display element. Of course, it is possible to place tempered glass separately on the upper surface side of the first housing 11 and the upper surface side of the second housing 12. In this case, however, a joint between the two pieces of tempered glass is created at the boundary between the upper surface of the first housing 11 and the upper surface of the second housing 12, making it impossible to realize a seamless single display screen.

[0019] Therefore, in the portable terminal 1 of this embodiment, a reinforcing plate is provided on the flexible portion 2. This maintains the strength of the portable terminal 1 at a high level. However, there is a concern that the reinforcing plate may affect detection of the indicated position through an electromagnetic induction type position detection sensor, making it impossible to detect the indicated position properly. Therefore, in the portable terminal 1, the reinforcing plate is also devised so that the indicated position can be properly detected through the electromagnetic induction type position detection sensor.

[0020] [Example of flexible section 2 configuration] 2 and 3 are diagrams for explaining the flexible part 2 mounted on the mobile terminal 1. As shown in FIG. 2, the flexible part 2 mounted on the mobile terminal 1 has a four-layer structure. Specifically, the top layer is a 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 this 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.

[0021] As an example, the thickness of each layer of the flexible part 2 is 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, the metal sheet 24 has a magnetic layer with a thickness of 50 μm on the position detection sensor 23 side, and a metal layer with a thickness of 50 μm on the lower side. As a result, the magnetic flux generated by the electromagnetic induction type position detection sensor 23 passes through the magnetic layer without penetrating the metal layer of the metal sheet 24 and heads toward the display element. Since the magnetic flux penetrating 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 prevents the magnetic flux generated by the position detection sensor 23 from reaching a position below the metal layer, and can prevent the magnetic influence from the electronic circuit located below the metal sheet 24 from being exerted.

[0022] It is desirable that the reinforcing plate 22 be made of a material that allows magnetic flux to pass appropriately and that does not easily generate eddy currents so as not to electrically affect the position detection sensor 23. In other words, it is desirable that the reinforcing plate 22 be made of a material that is non-magnetic and has low electrical conductivity. For this reason, in this embodiment, the reinforcing plate 22 is made of stainless steel. More specifically, the reinforcing plate 22 is made of stainless steel material with a JIS steel type number of SUS316.

[0023] Stainless steel material with JIS steel number SUS316 is suitable for use as the reinforcing plate 22 because it is nonmagnetic, does not easily produce magnetic poles, has high electrical resistance, is less likely to generate eddy currents, and has high rigidity. As shown in FIG. 3, the reinforcing plate 22 is 1.5 times thicker than the metal sheet 24, and therefore can increase the strength of the mobile terminal 1. Note that the reinforcing plate 22 is not limited to being made of SUS316 stainless steel material. It is of course possible to form the reinforcing plate 22 from other materials that are nonmagnetic, have low electrical conductivity, and have the desired rigidity, such as hard resin.

[0024] Even if the reinforcing plate 22 is made of a material having non-magnetic properties and high electrical resistance, it has a certain thickness. This impedes the transmission and reception of signals (magnetic flux) 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 to have the magnetic flux pass uniformly between the electromagnetic induction type position detection sensor 23 and the electromagnetic induction type electronic pen at any position in the position detection area of ​​the position detection sensor 23. Therefore, slits are provided in the reinforcing plate 22. In this case, depending on how the slits are provided, it is considered that the rigidity of the reinforcing plate 22 may be reduced, making it impossible to provide sufficient strength to the mobile terminal 1.

[0025] In addition, since the reinforcing plate 22 is provided on the back side of the flexible display element 21, the unevenness of the reinforcing plate 22 due to the slits may cause display unevenness. In addition, since the flexible display element 21 is thin and soft, it is considered that the unevenness of the slits formed in the reinforcing plate 22 provided on the back side of the flexible display element 21 affects the thickness of the drawn lines. In other words, it is considered that the thickness of the drawn lines will not be uniform, and thin and thick parts will occur, resulting in wavy lines.

[0026] Therefore, when providing slits in the reinforcing plate 22, the following three conditions must be satisfied: (1) magnetic flux must pass uniformly at any position in the position detection area; (2) the desired rigidity must be maintained; and (3) there must be no sparseness or density so as to prevent display unevenness or wavy images from occurring. As described later, the electromagnetic induction type position detection sensor 23 is configured by arranging multiple X-axis loop coils extending in the Y-axis direction (vertical direction) in the X-axis direction (horizontal direction) and arranging multiple Y-axis loop coils extending in the X-axis direction (horizontal direction) in the Y-axis direction (vertical direction). In this case, the X-axis loop coils are configured in a vertical straight line, and the Y-axis loop coils are configured in a horizontal straight line, so that the structural characteristics of such an electromagnetic induction type position detection sensor must also be taken into consideration.

[0027] Taking these 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 reinforcing plate 22 without any sparse or dense pattern so that their opening areas are approximately the same. The display screen of flexible display element 21, the slit area in which the slits of reinforcing plate 22 are provided, and the position detection area of ​​the electromagnetic induction type position detection sensor are made to be approximately the same in shape and area. Furthermore, in the optimal case, when the slit area is slightly wider, the influence of the frame portion described below can be further reduced, improving accuracy.

[0028] This makes it possible to increase the strength of the mobile terminal 1 by using the reinforcing plate 22 with slits formed therein to maintain rigidity over the entire surface of the display screen of the flexible display element 21. Moreover, the reinforcing plate 22 is provided with slits extending in the vertical direction of the display screen and slits extending in the horizontal direction of the display screen, evenly spaced so that the opening areas are approximately the same. Therefore, the unevenness caused by the formation of the slits is not noticeable, and transmission and reception of magnetic flux can be performed appropriately without being hindered.

[0029] [Example of configuration of reinforcing plate 22] Fig. 4 is a diagram for explaining the reinforcing plate 22 of the flexible part 2 mounted on the mobile terminal 1. In both Fig. 4(A) and (B), the slit area is formed by arranging H-shaped slits in the vertical and horizontal directions, the slit being similar in shape to the alphabet letter H, with two parallel rod-shaped slits of the same length connected at their midpoints by one rod-shaped slit. In the example shown in Fig. 4(A) and (B), the width of one rod-shaped slit (the width in the direction intersecting the longitudinal direction) is 0.5 mm.

[0030] Also, as shown by the black fill in the upper left corner of Fig. 4(A), a slit area is formed in the reinforcing plate 22 using three types of H-shaped slits with different lengths of a single rod-shaped slit connecting the midpoints of two parallel rod-shaped slits of the same length. As shown by the black fill in the upper left corner of Fig. 4(B), a slit area is formed in the reinforcing plate 22 using one type of H-shaped slit with a common length of a single rod-shaped slit connecting the midpoints of two parallel rod-shaped slits of the same length.

[0031] In the examples of Figures 4(A) and (B), H-shaped slits are arranged alternately in both the vertical and horizontal directions, with two slits of the same length located on the left and right, and two slits of the same length located on the top and bottom. In both of the examples of Figures 4(A) and (B), slits can be arranged uniformly in the slit area of ​​the reinforcing plate 22 without any sparseness or density. In other words, 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 approximately equal within the slit area. Therefore, the parts of the base metal in the slit area where no slits are provided also have a uniform distribution within the slit area. Distribute It is made to be like this.

[0032] As a result, even if slits are provided in the reinforcing plate 22, the overall rigidity of the reinforcing plate 22 is not deteriorated. Moreover, since the H-shaped slits can be provided uniformly across the entire slit area without any sparseness or denseness, the display screen does not become uneven, and there is no risk of display unevenness or wavy drawn lines. Of course, the uniformly provided H-shaped slits allow the magnetic flux to pass through and further suppress the generation of eddy currents due to the magnetic flux passing through the reinforcing plate 22, making it possible to properly transmit and receive the magnetic flux without impeding its transmission and reception.

[0033] The difference between Figure 4(A) and Figure 4(B) is the coupling rate of the magnetic flux. When there is no reinforcing plate 22, and the coupling rate of the magnetic flux between the position detection sensor 23 and the position indicator is 100%, the coupling rate in the case of Figure 4(A) is 89.1%, whereas the coupling rate in the case of Figure 4(B) is 88.1%. It was verified by experiment that the coupling rate is improved when slits of different lengths are used.

[0034] [Configuration of the bent part of the reinforcing plate] Fig. 5 is a diagram for explaining the bent portion of the reinforcing plate 22 of the flexible part 2 mounted on the mobile terminal 1. If slits are provided on the entire surface of the reinforcing plate 22 in the manner shown in Fig. 4(A) and (B), the mobile terminal 1 cannot be folded smoothly when folded as shown in Fig. 1(C). Since the bent portion contains a bare metal portion that is stretched in a direction intersecting the bent portion, the bent portion becomes difficult to bend and easily damaged.

[0035] Therefore, as shown in FIG. 5(A), a bent portion 22C is provided in the center of the reinforcing plate 22, with the left slit portion 22L on the left side and the right slit portion 22R on the right side. H-shaped slits are provided uniformly on the entire surface of the left slit portion 22L and the right slit portion 22R in the manner shown in FIG. 4(A) or FIG. 4(B). Also, as shown in FIG. 5(B), the bent portion 22C is formed in a mesh shape so as to have a plurality of openings in a substantially diamond shape. By forming the bent portion 22C in a mesh shape in this way, the bent portion 22C can be slightly stretched in the directions shown by the arrows a and b, and the bent portion 22C can be easily folded (folded in half).

[0036] Also, as shown in Fig. 5, a frame portion 22FL is provided around the reinforcing plate 22, which does not essentially have slits. The inside of this frame portion 22FL is a slit area, which corresponds to the display screen of the flexible display element and also 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, the frame portion 22FL does not essentially have slits. In order to prevent disturbance of the magnetic flux due to 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 can be further improved even at the edge of the display screen.

[0037] The upper and lower end portions of the folding portion 22C may be provided with slits in a mesh pattern, similar to the other portions of the folding portion 22C. This is to allow the mobile terminal 1 to be folded and unfolded smoothly. Also, the left slit portion 22L and the right slit portion 22R may be provided with slits in a mesh pattern, similar to the folding portion 22C. However, the mesh pattern (FIG. 5(B)) and the H-shaped slits (FIG. 5(C)) may be different from each other. slit Between Figs. 4(A) and (B), the provision of the H-shaped slits allows the rigidity to be maintained at a higher level.

[0038] Also, the folding portion 22C may be provided with an I-shaped slit along the crease, similar to the letter I. That is, the folding portion 22C may be configured by providing a plurality of slits extending along the crease. In this case, it becomes possible to fold smoothly without forming a bare metal portion extending in a direction intersecting the crease.

[0039] In addition, the left slit portion 22L and the right slit portion 22R have different slit shapes from the bent portion 22C, which may lead to erroneous detection of the indicated position at the bent portion 22C. For this reason, as described later, the detection output of the position detection sensor 23 at the bent portion 22C is corrected. This allows the indicated position to be detected in the same way as in the areas corresponding to the left slit portion 22L and the right slit portion 22R, which have H-shaped slits.

[0040] [Example of the configuration of an electromagnetic induction type position detection device] Fig. 6 is a block diagram for explaining a configuration example of a position detection device including an electromagnetic induction type position detection sensor 23. The electronic pen 300 is of the electromagnetic induction type, and as shown in the upper left of Fig. 6, includes a coil L for transmitting and receiving signals, a pen pressure detection unit Cv which is a variable capacitance capacitor, and a resonant circuit formed by connecting a resonant capacitor Cf and the like in parallel.

[0041] The position detection device 100 includes a position detection sensor 23 formed by stacking an X-axis loop coil group 23X and a Y-axis loop coil group 23Y. The loop coils X1, X2, ..., X 40 and the loop coils Y1, Y2, ..., Y of the Y-axis loop coil group 23Y. 30 Each of the positions may be one turn or two or more turns. As described above, such a position detection sensor 23 is disposed below the reinforcing plate 22 disposed on the back side of the flexible display element 21. The position detection sensor 23 is connected to a position detection circuit 101 to constitute a position detection device 100 as a whole.

[0042] 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 writing 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.

[0043] The processing control unit 109 is configured with 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 writing pressure detection circuit 108.

[0044] The oscillator 102 generates an AC signal with a frequency f0. The oscillator 102 supplies the generated AC signal to a current driver 103 and a 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 a switching connection circuit 105. Under the control of a processing control unit 109, 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. Of these connection destinations, the current driver 103 is connected to the transmission side terminal T, and the reception amplifier 106 is connected to the reception side terminal R.

[0045] The switching connection circuit 105 is switched to the transmitting terminal T side during the transmission period, and is switched to the receiving terminal R side during the reception period. As a result, during the transmission period, the loop coil that receives current from the current driver 103 through the transmitting terminal T generates a magnetic field, transmits it to the electronic pen 300, and acts on the resonant circuit of the electronic pen 300. In this case, the resonant circuit of the electronic pen 300 generates a position indication signal (radio wave) and transmits it to the position detection sensor 23 side.

[0046] 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 subjected to the effect 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 via 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 writing pressure detection circuit 108.

[0047] 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 waves transmitted from the electronic pen 300. For this reason, the position detection circuit 107 detects the induced voltage (received signal) generated in the loop coils, converts the detection 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 position 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, i.e., the level of the voltage value of the induced voltage generated in each loop coil.

[0048] On the other hand, the writing 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 shift) therebetween. In this case, the signal corresponding to the phase difference (frequency shift) is converted into a digital signal and output to the processing control unit 109. The processing control unit 109 detects the writing pressure applied to the electronic pen 300 based on the digital signal from the writing pressure detection circuit 108, i.e., the level of the signal corresponding to the phase difference (frequency shift) between the transmitted radio wave and the received radio wave.

[0049] As described above, the position detection circuit 107 and the writing pressure detection circuit 108 are adapted to correct the output signal from the loop coil in the portion corresponding to the bent portion 22C of the reinforcing plate 22 located on the upper surface side of the position detection sensor 23. As a result, the H-shaped slit is formed in the portion of the position detection sensor 23 corresponding to the bent portion 22C. Established Therefore, even if the pointing position is on the bent portion 22C, the pointing position and the writing pressure can be detected properly.

[0050] In this way, the position detection circuit 101 switches between a signal transmission period and a signal reception period, supplies driving power to the electronic pen 300 to drive it during the transmission period, and receives a signal from the electronic pen 300 to detect the indicated position and writing pressure during the reception period. This position detection circuit 101 is configured as a circuit board. Thus, by connecting a 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 can be mounted on the mobile terminal 1 as an input device.

[0051] In this manner, the portable terminal 1 of this embodiment is provided with the reinforcing plate 22 between the flexible display element 21 and the electromagnetic induction type position detection sensor 23. However, the reinforcing plate is formed of, for example, SUS316 stainless steel, but 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 with uniform slits. This allows the rigidity of the reinforcing plate 22 to be maintained and strength to be imparted to the portable terminal 1, and also allows signals to be appropriately transmitted and received between the electromagnetic induction type position detection sensor 23 and the electromagnetic induction type electronic pen 300 without causing display unevenness on the display screen. Of course, the portable terminal 1 can also be easily folded and unfolded.

[0052] [Other examples of flexible parts] The flexible part 2 of the portable terminal 1 in the embodiment described above is provided with the electromagnetic induction type position detection sensor 23. However, a capacitive type position detection sensor may be further provided in addition to the electromagnetic induction type position detection sensor 23. This makes it possible to realize a hybrid portable terminal 1 that allows both instruction input using a user's finger or a so-called electrostatic pen, and instruction input using an electromagnetic induction type electronic pen.

[0053] 7 and 8 are diagrams for explaining the flexible part 2A mounted on the mobile terminal 1A. In the flexible part 2A shown in FIG. 7 and FIG. 8, the same reference numerals are given to the parts configured similarly to the parts configuring the flexible part 2 shown in FIG. 2 and FIG. 3, and detailed description of those parts is omitted to avoid duplication. In FIG. 7 and FIG. 8, the capacitive position detection sensor (second position detection sensor) 25 can be configured transparently using thin linear electrodes, and therefore can be disposed on the upper surface side of the flexible display element 21. That is, as shown in FIG. 7, the flexible part 2A can be formed by laminating the capacitive position detection sensor 25, the flexible display element 21, the reinforcing plate 22, the electromagnetic induction position detection sensor 23, and the metal sheet 24 in this order from the top.

[0054] Therefore, as shown in Fig. 8, a flexible section 2A can be configured in which a capacitive position detection sensor 25, which is thinner and more transparent than the electromagnetic induction position detection sensor 23, is disposed on the upper surface side of the flexible display element 21. Even in this case, as shown in Fig. 7 and Fig. 8, a reinforcing plate 22 is provided between the flexible display element 21 and the electromagnetic coupling position detection sensor 23. As described above, this reinforcing plate 22 is non-magnetic and has high electrical resistance, so that eddy current is unlikely to occur.

[0055] 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 repeatedly change over time, eddy currents are unlikely to occur in the reinforcing plate 22. Therefore, there is no effect on detection of the indicated position through the capacitive position detection sensor 25. In other words, it is possible to configure a mobile terminal 1A that can satisfactorily detect the indicated position through the capacitive position detection sensor 25 and using the electromagnetic induction type position detection sensor 23. Moreover, the presence of the reinforcing plate 22 can increase the strength over the entire upper surface side of the mobile terminal 1 where the display screen of the flexible display element 21 is located, thereby realizing a mobile terminal 1 that has high strength even in the open state.

[0056] [Example of the configuration of a capacitive position detection device] 9 is a diagram for explaining a configuration example of a capacitive 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.

[0057] 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 includes, for example, a plurality of first conductors 25Y1 to 25Y2 extending in the horizontal direction (X-axis direction). m The second conductor group 252 is made up of a plurality of second conductors 25X1 to 25X2 extending in a direction intersecting the first conductors, in this example, in a vertical direction (Y-axis direction) perpendicular to the first conductors. n are arranged in parallel in the X-axis direction at a predetermined distance from each other.

[0058] In this way, the position detection sensor 25 of the position detection device 200 is configured to detect a position indicated by a user's finger or a capacitive electronic pen (electrostatic pen) using a sensor pattern formed by crossing the first conductor group 251 and the second conductor group 252. Note that in the description of FIG. 9, the first conductors 25Y1 to 25Y m When referring to one of the conductors, it is written as the first conductor 25Y, and when referring to the second conductors 25X1 to 25X n When referring to one of these, it is written as the second conductor 25X.

[0059] The position detection circuit 210 is made up of a selection circuit 211 which is an input / output interface with the position detection sensor 25, an amplifier circuit 212, a received signal processing circuit 213, and a control circuit 214. Although not shown, the received signal processing circuit 213 includes a bandpass filter, a detection circuit, a sample-and-hold circuit, an AD (Analog to Digital) conversion circuit, and the like.

[0060] The selection circuit 211 selects one conductor 25Y or 25X from 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 amplifier circuit 212, and a signal corresponding to a change in potential caused by contact with a user's finger or an electrostatic pen is detected by the selected conductor and amplified by the amplifier circuit 212. The output of the amplifier circuit 212 is supplied to a reception signal processing circuit 213. The reception signal processing circuit 213 band-limits the signal supplied thereto, performs detection processing, samples and holds it, converts it into a digital signal, and supplies it to the control circuit 214.

[0061] The control circuit 214 supplies a control signal to the selection circuit 211 to control it, and also supplies a control signal to the reception signal processing circuit 213 to control it, based on a program stored in an internal ROM (Read Only Memory). The control circuit 214 also calculates the position coordinates on the position detection sensor 25 indicated by the user's finger or electrostatic pen, based on the digital data from the reception signal processing circuit 213. When a so-called active electrostatic pen that transmits a position indication signal or a writing pressure signal is used, the control circuit 214 can also perform processing to detect the writing pressure detected by a writing pressure detection unit of the active electrostatic pen, based on the digital data from the reception signal processing circuit 213.

[0062] In this way, the position detection device 200 detects the position pointed to by the user's finger or electrostatic pen, and supplies the detected position to, for example, a computer device, so that processing according to the icon at the pointed position can be executed. In the case of a mobile terminal 1A equipped with both the capacitive position detection device 200 and the electromagnetic induction type position detection device 100 described with reference to FIG. 6, these can be used differently. That is, simple operations can be performed with the user's finger or the like, and instruction input can be received by the capacitive position detection device 200. In addition, when detailed drawing is desired, it can be performed using the electromagnetic induction type electronic pen 300, and instruction input can be received by the electromagnetic induction type position detection device 100.

[0063] Furthermore, even when the capacitance type position detection sensor 25 and the electromagnetic induction type position detection sensor 23 are mounted, the provision of the reinforcing plate 22 allows the stiffness of the reinforcing plate 22 to be maintained and strength to be imparted. At the same time, signals can be appropriately transmitted and received between the electromagnetic induction type position detection sensor 23 and the electromagnetic induction type electronic pen 300 without causing display unevenness or wavy drawing lines on the display screen. Of course, the mobile terminal 1 can also be easily folded and unfolded. Furthermore, the indicated position can be appropriately detected through the capacitance type position detection sensor 25 without being affected by the electromagnetic induction type position detection sensor 23.

[0064] [Effects of the embodiment] According to the mobile terminal 1 of the embodiment described above, by providing the reinforcing plate 22 between the flexible display element 21 and the electromagnetic induction type position detection sensor 23, the strength according to the rigidity of the reinforcing plate 22 can be given to the mobile terminal 1. Moreover, the reinforcing plate 22 has slits extending in the vertical direction of the display screen and slits extending in the horizontal direction uniformly arranged so that the opening areas are almost the same over the entire slit area. It will be established. This prevents display unevenness, and allows magnetic flux to be sent and received appropriately at any position in the slit area without being hindered. Furthermore, in the case of the mobile terminal 1A described above, even if a capacitive position detection sensor 25 is disposed on the upper surface of the flexible display element 21, the reinforcing plate 22 prevents the sensor from being affected by the electromagnetic induction position detection sensor 23. Therefore, the indicated position can be detected appropriately through the capacitive position detection sensor 25.

[0065] [Modifications, etc.] 10A and 10B are diagrams for explaining the shape pattern of the slits provided in the slit portion of the reinforcing plate. In the above-mentioned embodiment, as shown in FIG. 10A, two parallel slits of the same length are provided. slit By connecting the midpoints of the two slits with one slit, an H-shaped slit similar in shape to the alphabet letter H is used. However, the present invention is not limited to this.

[0066] For example, as shown in Fig. 10(B), a single bar-shaped I-shaped slit similar to the alphabetical letter I may be arranged uniformly without sparseness or density in the slit area of ​​reinforcing plate 22 while changing the arrangement direction. Also, as shown in Fig. 10(C), a T-shaped slit consisting of a horizontal bar and a vertical bar similar to the alphabetical letter T may be arranged uniformly without sparseness or density in the slit area of ​​reinforcing plate 22. Also, as shown in Fig. 10(D), a Z-shaped slit consisting of two horizontal bars similar to the alphabetical letter Z and a diagonal bar connecting them may be arranged uniformly without sparseness or density in the slit area of ​​reinforcing plate 22.

[0067] Also, slits of different shapes (shapes) may be combined to form slits in the slit area of ​​the reinforcing plate 22, for example, by combining an H-shaped slit with an I-shaped slit or by combining an H-shaped slit with a T-shaped slit. In addition, the shape of the slits provided in the slit area of ​​the reinforcing plate 22 may be various. In this case, it is important that (1) the rigidity of the reinforcing plate 22 is not deteriorated; (2) the interval at which the slits are provided is not large, which causes unevenness in the display screen of the flexible display element 21 and causes display unevenness; and (3) between the electromagnetic induction type position detection sensor 23 and the electromagnetic induction type electronic pen 300, magnetic flux is equally uniformly transmitted and received at any position in the position detection area of ​​the position detection sensor 23.

[0068] In the above-described embodiment, the flexible display element 21 is used to realize the foldable mobile terminal 1. 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 considered to be advantages of paper, and allows the display content to be electrically rewritten. The structure of electronic paper is simply a display in which a large number of tiny spheres, one of which is painted white and the other half black, are embedded in the display, and some of the spheres are charged with static electricity, and black characters are made to appear on a white background by rotating the spheres using an electric field. In recent years, some of these spheres are capable of displaying in color.

[0069] In addition, 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, but by using the present invention, when a flexible display element such as an OLED or electronic paper is used as the display element, strength can be added to the mobile terminal without using reinforced glass. Therefore, the present invention is more suitable for use in forming a so-called foldable terminal using a flexible display element. [Explanation of symbols]

[0070] Reference Signs List 1, 1A...mobile terminal, 11...first housing, 12...second housing, 13...cover portion, 2, 2A...flexible portion, 21...flexible display element, 22...reinforcing plate, 22L...left side slit portion, 22R...right side slit portion, 22C...folded portion, 22FL...frame portion, 23...electromagnetic induction type position detection sensor, 24...metal sheet, 25...capacitive type position detection sensor, 100...electromagnetic induction type position detection device, 200...capacitive 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 surface side of the display element and configured to detect a pointed position on a display screen of the display element; a reinforcing plate disposed between the display element and the first position detection sensor, the reinforcing plate having a slit portion corresponding to the entire surface of the display screen, the slit portion having slits extending in the vertical direction of the display screen and slits extending in the horizontal direction of the display screen uniformly provided so that the opening areas are substantially the same; 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 and low-conductive 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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