Sensor substrate and display device

Abstract

The present application relates to a sensor substrate and a display device. The sensor substrate (100) includes: a light emitting element array (106) in which a plurality of light emitting elements (104) are arranged two-dimensionally; and a plurality of loop coils (120) for detecting a pointing position of an electronic pen by electromagnetic induction generated between the electronic pen. A loop wiring line constituted by a linear wiring line (110) connected to the light emitting element array (106) and the plurality of loop coils (120) is partially shared.

Description

Technical Field

[0001] This invention relates to sensor substrates and display devices. Background Technology

[0002] In the past, in the field of display device technology, direct-lit backlights are known to form a surface light source by arranging an array of light-emitting elements on the back side of a display panel (for example, see Patent Documents 1-3). Hereinafter, the electronic circuit board on which the array of light-emitting elements is mounted is sometimes referred to as a "light source board".

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2002-258770

[0006] Patent Document 2: Japanese Patent Application Publication No. 2016-066598

[0007] Patent Document 3: Japanese Patent Application Publication No. 2019-016631 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] To enable writing functionality in the aforementioned display device, a position detection sensor is sometimes incorporated into the back side of the display panel. Examples of such sensors include electromagnetic induction (EMR) methods, which detect alternating magnetic fields emitted from a position indicator using multiple loop coils arranged in one or two dimensions. Hereinafter, the electronic circuit board in which the position detection sensor is mounted will sometimes be referred to as a "sensor board."

[0010] The aforementioned light source substrate and sensor substrate are preferably positioned closer to the display panel and arranged parallel to it to fulfill their respective functions (i.e., light emission or detection). This allows for a device structure where the substrates are arranged parallel to each other and facing each other. However, this arrangement can lead to electromagnetic interference between the linear wiring mounted on the light source substrate and the coil wiring mounted on the sensor substrate. As a result, electromagnetic noise can be introduced into the coil wiring, potentially causing a decrease in detection accuracy and malfunction of the sensor substrate.

[0011] The present invention was made in view of the following problems, and its object is to provide a sensor substrate and a display device capable of suppressing the generation of electromagnetic noise associated with electromagnetic interference between the wirings of the light source substrate and the sensor substrate respectively.

[0012] Methods for solving problems

[0013] The sensor substrate of the first invention comprises: a light-emitting element array having a plurality of light-emitting elements arranged in two dimensions; and a plurality of ring coils for detecting the indicated position of the electronic pen by electromagnetic induction generated between the plurality of ring coils and the electronic pen of electromagnetic induction mode, wherein the linear wiring connected to the light-emitting element array and the coil wiring formed by the plurality of ring coils are partially shared.

[0014] The second display device of the present invention includes: a light source substrate having a plurality of light-emitting elements arranged in two dimensions; and a sensor substrate having a plurality of annular coils formed thereon extending in a first direction and / or a second direction intersecting the first direction, wherein a two-dimensional position indicated by the electronic pen is detected by electromagnetic induction generated between the plurality of annular coils and an electronic pen, wherein the light source substrate and the sensor substrate are arranged opposite each other while maintaining a parallel relationship, and on the light source substrate, linear wiring connected to each of the light-emitting elements is wired along a third direction, wherein the third direction is inclined relative to both the first direction and the second direction.

[0015] Invention Effects

[0016] According to the present invention, it is possible to suppress the generation of electromagnetic noise associated with electromagnetic interference between the wirings of the light source substrate and the sensor substrate. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a display device that is applicable to all embodiments of the present invention.

[0018] Figure 2 This is an exploded perspective view showing the main parts of the display device in the first embodiment.

[0019] Figure 3 It is shown Figure 2 A diagram showing an example of the circuit structure of a sensor substrate.

[0020] Figure 4 It is shown Figure 2 A diagram showing an example of the wiring structure of a light source substrate.

[0021] Figure 5 It is shown Figure 4 A diagram illustrating the effect of the wiring configuration.

[0022] Figure 6 This is a circuit structure diagram of the sensor substrate in a modified example of the first embodiment.

[0023] Figure 7 This is an exploded perspective view showing the main parts of the display device in the second embodiment.

[0024] Figure 8It is shown Figure 7 The first figure shows a portion of the wiring structure of a sensor substrate with a light source.

[0025] Figure 9 It is shown Figure 7 The second figure shows a portion of the wiring structure of a sensor substrate with a light source. Detailed Implementation

[0026] The following is a reference to the appendix. Figure 1 The embodiments of the present invention will be described below. To facilitate understanding, the same reference numerals will be used for the same constituent elements in the accompanying drawings as much as possible, and repeated descriptions will be omitted.

[0027] [Overall Structure]

[0028] Figure 1 This is a cross-sectional view of a display device 10 that is common to all embodiments of the present invention. Here, it is envisioned that the display device 10 is assembled using a semi-finished product called an "Open Cell" without a backlight module. Specifically, the display device 10 is configured to include a housing 12, a substrate assembly 14, a liquid crystal panel 16, and a transparent protective plate 18. The housing 12 is constructed by combining a low-height cuboid-shaped back cover 20 and a support frame 30 with a generally H-shaped cross-section.

[0029] The back cover 20 opens upwards and houses the substrate assembly 14 in a state where it is in surface contact with the bottom 22. The support frame 30 has a frame-shaped portion 32, a first protrusion 34 protruding downwards from the outside of the frame portion 32, and a second protrusion 36 protruding downwards from the inside of the frame portion 32. The first protrusion 34 is configured to engage with the side portion 24 of the back cover 20. The second protrusion 36 is configured to fix the substrate assembly 14 by pressing it down from above.

[0030] The substrate assembly 14 is formed by stacking at least a plurality of substrates that perform both light-emitting and pen-detection functions. The light-emitting function refers to the function of emitting illumination light (so-called backlight) from the back of the liquid crystal panel 16 toward the front. The pen-detection function refers to the function of detecting the position indicated by an electronic pen using electromagnetic induction (EMR).

[0031] The transparent protective plate 18 is a plate-shaped component with high light transmittance used to protect the display surface of the liquid crystal panel 16, and is made of, for example, glass. The liquid crystal panel 16 is bonded to the back of the transparent protective plate 18 via an optical adhesive layer 40. That is, the transparent protective plate 18 supports the liquid crystal panel 16 from above by fixing it via the display surface. It should be noted that the material used for the optical adhesive layer 40 is, for example, optically clear adhesive sheet (OCA) or optically clear resin (OCR).

[0032] Furthermore, on the back of the transparent protective plate 18, a plurality of protrusions 42 are formed at a position further outward than the fixing portion of the liquid crystal panel 16. The support frame 30 fixes and supports the transparent protective plate 18 in a state where the recesses 38 and the protrusions 42 engage. In this case, the support frame 30 and the liquid crystal panel 16 are in a positional relationship that does not overlap in the top view. The reason for this will be explained below.

[0033] For example, the support frame 30 can also be constructed such that it protrudes vertically inward from the second protrusion 36 and partially supports the liquid crystal panel 16 from below. However, when the user presses the transparent protective plate 18 downward during use of the display device 10, the non-display surface of the liquid crystal panel 16 comes into contact with the support frame 30, and sometimes the periphery of the liquid crystal panel 16 tilts. As a result, the light-shielding function of the liquid crystal is partially unable to function, and the illumination light emitted from the substrate assembly 14 may leak through the periphery of the liquid crystal panel 16. Consequently, the display quality of the display device 10 deteriorates.

[0034] then, Figure 1 The display device 10 includes: a substrate assembly 14; a liquid crystal panel 16 disposed directly above the substrate assembly 14 and having a display surface; a transparent protective plate 18 that supports the liquid crystal panel 16 from above by being fixed via the display surface; and a housing 12 having a support frame 30 for supporting the transparent protective plate 18 and housing the substrate assembly 14. Furthermore, the support frame 30 and the liquid crystal panel 16 are arranged in a manner that does not overlap in a top view.

[0035] With this configuration, even when the transparent protective plate 18 is pressed downwards, interference between the non-display surface of the liquid crystal panel 16 and the support frame 30 can be avoided, and leakage of illumination light caused by the tilt of the liquid crystal panel 16 can be suppressed.

[0036] [First Implementation Method]

[0037] Next, regarding the substrate assembly 14A incorporated into the display device 10 in the first embodiment, while referring to... Figures 2-5 While explaining.

[0038] <Structure>

[0039] Figure 2 This is an exploded perspective view showing the main parts of the display device 10 in the first embodiment. More specifically, this figure schematically shows the stacking relationship between the substrate assembly 14A and the liquid crystal panel 16 in the first embodiment. The substrate assembly 14A is constructed by stacking a light source substrate 50, a sensor substrate 52, and a driving substrate 54 in order from near to far from the liquid crystal panel 16. The driving substrate 54 is connected to the light source substrate 50 via a flexible printed circuit board (hereinafter referred to as FPC 56), and the LED array 84 described later (see reference) is also present. Figure 4 ) drive control.

[0040] Figure 3 It is shown Figure 2 The figure shows an example of the circuit structure of the sensor substrate 52. The sensor substrate 52 detects the two-dimensional position indicated by the electronic pen by electromagnetic induction generated between the loop coils 70, 72 and the electronic pen. Specifically, various electronic components, including a sensor section 60, a selection circuit 62, a switch 64, a transmitting amplifier 66, and a receiving amplifier 68, are provided on the front or back of the sensor substrate 52.

[0041] The sensor unit 60 is configured to include a first ring coil group 70G and a second ring coil group 72G. The first ring coil group 70G and the second ring coil group 72G are arranged in a way that they intersect each other to form a two-dimensional grid. As a result, a rectangular detection area 74 is formed for indicating the two-dimensional position in the XY coordinates.

[0042] The first ring coil group 70G is an assembly of coil wiring consisting of N (N≥2) ring coils 70 arranged in the X direction and extending in the Y direction. Each ring coil 70 has a rectangular shape as a long strip with a substantially constant width regardless of its position in the Y direction. Each ring coil 70 is connected to the selection circuit 62 at one end and to a reference potential (e.g., ground potential) at the other end.

[0043] The second ring coil group 72G is an assembly of coil wiring consisting of M (M≥2) ring coils 72 arranged in the Y direction and extending in the X direction. Each ring coil 72, like the ring coil 70, has a rectangular shape as a long strip with a substantially constant width regardless of its position in the X direction. Each ring coil 72 is connected at one end to the selection circuit 62 and at the other end to a reference potential (e.g., ground potential).

[0044] The selection circuit 62 switches the connection destination between the sensor units 60 according to a control signal from a controller (not shown). Thus, one loop coil 70 from the first loop coil group 70G is selectively connected to the switch 64. Alternatively, one loop coil 72 from the second loop coil group 72G is selectively connected to the switch 64.

[0045] Switch 64 switches the connection destination to either the T terminal or the R terminal based on a control signal from a controller (not shown). For example, when the connection destination is the T terminal, switch 64 outputs a transmit signal supplied from the transmit amplifier 66 to the sensor unit 60. On the other hand, when the connection destination is the R terminal, switch 64 outputs a receive signal supplied from the sensor unit 60 to the receive amplifier 68.

[0046] Figure 4 It is shown Figure 2 This diagram illustrates an example of the wiring structure of the light source substrate 50. An LED array 84, consisting of a collection of light-emitting diodes (hereinafter referred to as LED82), is provided on the main surface 80 of the light source substrate 50. In the LED array 84, a plurality of LEDs 82 are arranged in a grid pattern with the X and Y directions as two axes. Linear wiring, which is routed to an FPC 56 or FPC 58, is provided on the anode and cathode sides of each LED 82. For ease of illustration, only the cathode wire is shown here.

[0047] Multiple linear wires 86 extend in the D direction, which is inclined relative to both the X and Y directions, and are arranged at approximately equal intervals. At least one LED 82 is connected to each linear wire 86 in its vicinity. For example, five LEDs are connected to a numbered linear wire 86. The inclination angle relative to the X direction is preferably in the range of 15 to 75 degrees, and more preferably in the range of 30 to 60 degrees.

[0048] <Effects>

[0049] The substrate assembly 14A in the first embodiment is configured as described above. Next, regarding this... Figure 4 The effect of the wiring structure, while referring to Figure 5 While explaining. Figure 5 The left side shows a "comparative example". Figure 5 The right side shows an "Example".

[0050] exist Figure 5In the "comparative example," we envision a scenario where the linear wiring 88Y is arranged parallel to the Y-direction along the arrangement direction of the LED array 84. When the light source substrate 50 and the sensor substrate 52 are positioned relative to each other while maintaining a parallel relationship, electromagnetic interference may sometimes occur between the loop coil 70 and the linear wiring 88Y. In particular, as the parallel wiring section lengthens, electromagnetic noise is easily conducted spatially through floating capacitance, magnetic coupling, etc. As a result, electromagnetic noise may be introduced into the loop coil 70, potentially leading to a decrease in detection accuracy and malfunction of the sensor substrate 52.

[0051] On the other hand, Figure 5 In the "embodiment," the linear wiring 88 extends obliquely relative to both the X and Y directions. In this case, even when the light source substrate 50 and the sensor substrate 52 are arranged parallel to each other and facing each other, the loop coil 70 and the linear wiring 88 are in a "twisted position." This reduces the likelihood of electromagnetic noise entering the loop coil 70 due to the cancellation effect of electromagnetic waves generated between the loop coil 70 and the linear wiring 88. As a result, a decrease in detection accuracy and malfunctions of the sensor substrate 52 are suppressed.

[0052] As described above, the display device 10 in the first embodiment includes: a light source substrate 50 on which a plurality of LEDs 82 (light-emitting elements) are arranged in two dimensions; and a sensor substrate 52 that detects a two-dimensional position indicated by an electronic pen through electromagnetic induction generated between a plurality of loop coils 70, 72 and an electronic pen. The plurality of loop coils 70, 72 extend in the X direction (first direction) and / or in the Y direction (second direction) intersecting the X direction. The light source substrate 50 and the sensor substrate 52 are arranged opposite each other while maintaining a parallel relationship. On the light source substrate 50, linear wiring 86 connected to each of the LEDs 82 is routed along the D direction (third direction), which is inclined relative to both the X and Y directions.

[0053] With this configuration, even when the light source substrate 50 and the sensor substrate 52 are arranged relative to each other while maintaining a parallel relationship, it is possible to prevent the linear wiring 86 and the loop coils 70 and 72 from becoming substantially parallel. As a result, the generation of electromagnetic noise associated with electromagnetic interference between the wirings of the light source substrate 50 and the sensor substrate 52 can be suppressed.

[0054] Alternatively, multiple ring coils may include a first ring coil group 70G and a second ring coil group 72G. The first ring coil group 70G is arranged in the X direction and extends in the Y direction, and the second ring coil group 72G is arranged in the Y direction and extends in the X direction. The first ring coil group 70G and the second ring coil group 72G are arranged to intersect each other to form a two-dimensional grid. In this way, it is possible to simultaneously prevent [1] the linear wiring 86 and the ring coil 70 from being parallel, and [2] the linear wiring 86 and the ring coil 72 from being parallel.

[0055] <Variation Example>

[0056] Figure 6 This is a circuit diagram of the sensor substrate 52A in a variation of the first embodiment. Various electronic components, including a sensor unit 90, a selection circuit 62, a switch 64, a transmitting amplifier 66, and a receiving amplifier 68, are provided on the front or back of the sensor substrate 52A. In other words, compared to the sensor substrate 52 in the first embodiment, the sensor unit 60 ( Figure 3 The wiring structure differs from that of the other components. The sensor unit 90 is configured to include a first ring coil group 92G and a second ring coil group 94G. This forms a rectangular detection area 96 for indicating a two-dimensional position in the XY coordinate system.

[0057] The first ring coil group 92G is an assembly of coil wiring consisting of N×M / 2 (N, M≥2) ring coils 92 arranged in the X direction and extending in the Y direction. Each ring coil 92 has a bulging, square-shaped top end. Each ring coil 92 is connected to the selection circuit 62 at one end and to a reference potential (e.g., ground potential) at the other end.

[0058] The second ring coil group 94G is an assembly of coil wiring consisting of N×M / 2 ring coils 94 arranged in the Y direction and extending in the X direction. Each ring coil 94, like the ring coil 92, has a bulging, square-shaped top end. Each ring coil 94 is connected to the selection circuit 62 at one end and to a reference potential (e.g., ground potential) at the other end.

[0059] The first ring coil group 92G and the second ring coil group 94G are arranged such that the M×N top ends form a two-dimensional grid. In the example shown in this figure, the first ring coil group 92G and the second ring coil group 94G are complementaryly arranged to form a square pattern. It should be noted that the relationship (position, arrangement, number, etc.) between the ring coils 92 and 94 is not limited to this. For example, the sensor unit 90 can also be constructed using only the first ring coil group 92G or only the second ring coil group 94G.

[0060] Thus, multiple ring coils 92, 94 can also have block-shaped bulging top portions, and are arranged in such a way that the top portions form a two-dimensional grid. With this structure, similar to the first embodiment, it is possible to simultaneously prevent [1] linear wiring 86 ( Figure 4 ) and the ring coil 92 are parallel, [2] the linear wiring 86 and the ring coil 94 are parallel.

[0061] [Second Implementation]

[0062] Next, regarding the substrate assembly 14B incorporated into the display device 10 in the second embodiment, while referring to... Figures 7-9 While explaining.

[0063] <Structure>

[0064] Figure 7 This is an exploded perspective view showing the main parts of the display device 10 in the second embodiment. More specifically, this figure schematically shows the stacking relationship between the substrate assembly 14B and the liquid crystal panel 16 in the second embodiment. The substrate assembly 14B is constructed by stacking a sensor substrate 100 with a light source and a driving substrate 54 in order from near to far from the liquid crystal panel 16. The driving substrate 54 is connected to the sensor substrate 100 with a light source via an FPC 56, and the LED array 106 described later (see reference) is also present. Figure 8 ) drive control.

[0065] Figure 8 It is shown Figure 7 The first figure shows an example of the wiring structure of a sensor substrate 100 with a light source. In this figure, the main parts of the wiring structure related to the light-emitting function are mainly extracted and shown. An LED array 106, a collection of light-emitting diodes (hereinafter referred to as LED104), is provided on the main surface 102 of the sensor substrate 100 with a light source. In the LED array 106, a plurality of LEDs 104 are arranged in a grid pattern with the X and Y directions as two axes. Individual linear wiring 108 is connected to the anode side of each LED 104. On the other hand, a common linear wiring 110 is connected to the cathode side of each LED 104.

[0066] Figure 9 It is shown Figure 7 The second figure shows an example of the wiring structure of the sensor substrate 100 with a light source. In this figure, the main parts of the wiring structure related to the detection function are mainly extracted and shown. The sensor substrate 100 with a light source detects a two-dimensional position indicated by an electronic pen through electromagnetic induction generated between the loop coil 120 and the electronic pen. Specifically, the sensor substrate 100 with a light source is configured to include a first loop coil group 120G and a wiring structure similar to that in the first embodiment (…). Figure 3 The selection circuit 62) has the same function as the selection circuit 122. It should be noted that although the illustration is omitted, the sensor substrate 100 with a light source and the first embodiment ( Figure 3 The structure of the device is similarly equipped with a variety of electronic components, including switches, transmitting amplifiers, and receiving amplifiers.

[0067] The first ring coil group 120G is an assembly of coil wiring consisting of N (N≥2) ring coils 120 arranged in the X direction and extending in the Y direction. Each ring coil 120 has a rectangular shape as a long strip with a substantially constant width regardless of its position in the Y direction. Each ring coil 120 is connected to the selection circuit 122 at one end and to the ground wire 124 at the other end.

[0068] The anode side of LED 104 is connected to the driver substrate 54 via a linear wiring 108. Figure 7 On the other hand, the cathode side of LED104 is connected to ground wire 124 via linear wiring 110. Only one LED104 is shown here. Figure 8 However, the other LEDs 104 not shown are also wired in the same way.

[0069] It should be noted that in this figure, only the first annular coil group 120G for detecting the indicator position in the X direction is shown, but please note that it is different from the first embodiment ( Figure 3 Similarly, a second ring coil group for detecting the position indicator in the Y direction is also provided. Alternatively, it is also possible to use... Figure 6 The wiring configuration shown.

[0070] <Effects>

[0071] As described above, the sensor substrate 100 with a light source includes: an LED array 106 (light-emitting element array) with a plurality of LEDs 104 (light-emitting elements) arranged in two dimensions; and a plurality of ring coils 120 for detecting the indicated position of the electronic pen by electromagnetic induction generated between the plurality of ring coils and the electronic pen. The linear wiring connected to the LED array 106 and the coil wiring formed by the plurality of ring coils 120 are partially shared. For example, one end of the linear wiring 110 connected to the cathode side of two or more LEDs 104 and one end of the two or more ring coils 120 are connected to a common ground wire 122.

[0072] In this way, by sharing the linear wiring connected to the LED array 106 and the coil wiring formed by the multiple loop coils 120, the configuration relationship between the separately provided light source substrate and sensor substrate can be disregarded. This suppresses the generation of electromagnetic noise associated with electromagnetic interference between the wiring of the light source substrate and the sensor substrate. Furthermore, the integration of the circuit board reduces manufacturing costs and installation space.

[0073] [Variation Example]

[0074] It should be noted that the present invention is not limited to the above-described embodiments and modifications, and can be freely modified without departing from the spirit of the invention. Alternatively, the various structures can be arbitrarily combined without causing technical inconsistencies.

[0075] In the above embodiments, for Figure 1 The display device 10 has been described with a "direct-lit" backlight structure, but the backlighting method is not limited to this. For example, a "side-lit" backlighting with light-emitting elements arranged on the side of the display surface can also be incorporated into the display device.

[0076] In the first embodiment described above, for in Figure 3 The case where a light-emitting diode (LED) is provided on the light source substrate 50 has been described, but the light-emitting element is not limited to this. For example, the light-emitting element may also be an organic LED (OLED) or a laser diode. Furthermore, regarding the second embodiment (… Figure 8 The same applies to the light-emitting elements in ().

[0077] [Label Explanation]

[0078] 10… Display device, 12… Housing, 14, 14A, 14B… Substrate assembly, 16… Liquid crystal panel, 18… Transparent protective plate, 30… Support frame, 50… Light source substrate, 52, 52A, 90… Sensor substrate, 70G, 92G, 120G… First ring coil assembly, 72G, 94G… Second ring coil assembly, 82, 104… LED (light-emitting element), 100… Sensor substrate with light source (sensor substrate).

Claims

1. A display device comprising: A light source substrate, on which multiple light-emitting elements are arranged in a two-dimensional manner; and A sensor substrate has a plurality of loop coils extending in a first direction and / or a second direction intersecting the first direction. The two-dimensional position indicated by the electronic pen is detected by electromagnetic induction generated between the plurality of loop coils and the electronic pen. The light source substrate and the sensor substrate are configured relative to each other while maintaining a parallel relationship. On the light source substrate, the linear wiring connected to each of the light-emitting elements is routed along a third direction, which is inclined relative to both the first direction and the second direction.

2. The display device according to claim 1, wherein, The plurality of ring coils includes a first ring coil group and a second ring coil group, wherein the first ring coil group is arranged in the first direction and extends in the second direction, and the second ring coil group is arranged in the second direction and extends in the first direction. The first and second ring coil groups are arranged in a way that they intersect each other to form a two-dimensional grid.

3. The display device according to claim 1, wherein, The plurality of ring coils have block-shaped bulging top portions and are arranged in such a way that the top portions form a two-dimensional lattice.

4. The display device according to any one of claims 1 to 3, wherein, The display device also includes: A liquid crystal panel is disposed directly above the light source substrate and has a display surface; A transparent protective plate supports the liquid crystal panel from above by being fixed via the display surface; and The housing has a support frame that supports the transparent protective plate and houses the light source substrate and the sensor substrate. The support frame and the liquid crystal panel are arranged in a manner that does not overlap in a top view.

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