FORCE SENSING DEVICE AND DISPLAY DEVICE COMPRISING THE SAME

• US 20180031885A1
• Filed: 07/31/2017
• Published: 02/01/2018
• Est. Priority Date: 08/01/2016
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: NAKAMORI, Yosuke, HIRABAYASHI, Ken
• Granted Patent: US 10,809,555 B2
• Time in Patent Office: Days
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02B 6/0088 of the light guide or other optical sheets in the package
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

According to one embodiment, a force sensing device includes a first insulating layer, a first electrode layer on the first insulating layer, a second electrode layer provided in opposition to the first electrode layer, and an elastic layer held between one or both of the first insulating layer and the first electrode layer, and the second electrode layer, and configured to prevent the first and second electrode layers from coming into contact with each other even while allowing the first and second electrode layers to get close to each other. When the first electrode layer or the second electrode layer is pressed, the pressing force is sensed on the basis of a variation in the capacitance between the first electrode layer and the second electrode layer.

Claims

1. A force sensing device comprising:

a first insulating layer;

a first electrode layer on the first insulating layer;

a second electrode layer provided in opposition to the first electrode layer; and

an elastic layer held between one or both of the first insulating layer and the first electrode layer, and the second electrode layer, and configured to prevent the first and second electrode layers from coming into contact with each other even while allowing the first and second electrode layers to get close to each other, wherein

when the first electrode layer or the second electrode layer is pressed, the pressing force is sensed on the basis of a variation in the capacitance between the first electrode layer and the second electrode layer corresponding to a variation in a distance between the first electrode layer and the second electrode layer.

2. The force sensing device of claim 1, wherein

one of the first electrode layer and the second electrode layer comprises a plurality of electrodes arranged at intervals, and the other electrode layer comprises a planar common electrode opposed to the plurality of electrodes.

3. The force sensing device of claim 1, wherein

the first electrode layer comprises a plurality of first electrodes arranged at intervals, and the second electrode layer comprises a plurality of second electrodes arranged at intervals.

4. The force sensing device of claim 1, further comprising a second insulating layer opposed to the first insulating layer with the first electrode layer and the second electrode layer interposed between the second insulating layer and the first insulating layer, wherein

the second electrode layer is provided on the second insulating layer.

5. The force sensing device of claim 4, wherein

the first insulating layer and the second insulating layer are formed of a continuous common insulating layer including a turnaround part.

6. The force sensing device of claim 1, wherein

the elastic layer is opposed to the first insulating layer and covers the first electrode layer and the second electrode layer.

7. The force sensing device of claim 2, wherein

the elastic layer comprises a plurality of belt-shaped or a plurality of dot-shaped elastic bodies held between the plurality of electrodes and the other electrode layer.

8. The force sensing device of claim 2, wherein

the elastic layer includes a plurality of belt-shaped or a plurality of dot-shaped elastic bodies arranged between the plurality of electrodes and held between the first insulating layer and the other electrode layer.

9. The force sensing device of claim 8, further comprising an insulating layer formed on each of the plurality of electrodes.

10. The force sensing device of claim 1, wherein

the elastic layer possesses disposition density distributions differing between a central part of the first insulating layer and a peripheral edge part thereof.

11. The force sensing device of claim 10, wherein

the disposition density distribution of the elastic layer at the peripheral edge part is lower than the disposition density distribution thereof at the central part.

12. A display device comprising:

a display panel comprising a first substrate; and

a force sensing device opposed to the first substrate and configured to sense a pressing force input to the display panel, wherein

the force sensing device comprises a first insulating layer, a first electrode layer on the first insulating layer, a second electrode layer opposed to the first electrode layer, and an elastic layer between one or both of the first insulating layer and the first electrode layer, and the second electrode layer, and configured to prevent the first and second electrode layers from coming into contact with each other even while allowing the first and second electrode layers to get close to each other.

13. The display device of claim 12, wherein

the force sensing device comprises a second insulating layer opposed to the first insulating layer with the first electrode layer and the second electrode layer interposed between the first and second insulating layers, and the second electrode layer is provided on the second insulating layer.

14. The display device of claim 13, wherein

the second insulating layer is stuck to the display panel.

15. The display device of claim 13, further comprising a flexible printed circuit board joined to the display panel, wherein

the first insulating layer and the first electrode layer of the force sensing device are respectively formed integral with an insulating layer and a conductive layer of the flexible printed circuit board.

16. The display device of claim 15, further comprising:

a touch sensor including first sensing electrodes on the display panel, and second sensing electrodes opposed to the first sensing electrodes with a gap held between the second sensing electrodes and the first sensing electrodes; and

a sensing drive element on the flexible printed circuit board, configured to receive a sensing signal from the first sensing electrodes or from the second sensing electrodes, and carry out touch sensing, wherein

the sensing drive element is connected to the first electrode layer or the second electrode layer of the force sensing device through the flexible printed circuit board, and receives a sensing signal from the force sensing device to carry out pressing force sensing.

17. The display device of claim 12, further comprising a backlight device including a light guide opposed to the display panel, a light source configured to make light incident on the light guide, and a case including a bottom plate opposed to the light guide, wherein

the display panel comprises a second substrate opposed to the first substrate, and a liquid crystal layer sealed between the first substrate and the second substrate.

18. The display device of claim 17, wherein

the force sensing device comprises a second insulating layer opposed to the first insulating layer with the first electrode layer and the second electrode layer interposed between the second insulating layer and the first insulating layer,

the second electrode layer is provided on the second insulating layer, and

the force sensing device is provided in the backlight device between the light guide and the bottom plate.

19. The display device of claim 17, wherein

the bottom plate of the case constitutes the second electrode of the force sensing device,

the first insulating layer of the force sensing device is stuck to the bottom plate, and

the elastic layer abuts on the bottom plate.

20. The display device of claim 17, wherein

the force sensing device is formed of a material possessing optical transparency, and is provided between the backlight device and the display panel or on the display panel.