Display device with integral touch panel surface
View Patent ↗A touch panel is integrated into a flat panel display device having a visual display surface with a front polarizer layer, particularly a liquid crystal display device. The touch panel comprises a flexible transparent membrane containing the front polarizer layer and having a first transparent conductive layer on a lower surface of the flexible transparent membrane and a rigid base comprising the flat panel display device and having a second transparent conductive layer on an upper surface of the rigid base. At least one spacer separates the flexible transparent membrane from the rigid base, keeping the first and second transparent conductive layers in spaced-apart facing relationship. A bus bar and tail communicate a signal from the touch panel to the flat panel display device.
1. A flat panel liquid crystal display device comprising:
a front transparent rigid base;
a rear transparent base;
a liquid crystal fluid layer sandwiched between the front and rear bases;
a rear polarizer layer on the rear transparent base; and
a touch panel integrated into the display device over the front transparent rigid base, the touch panel comprising:
a transparent flexible membrane including a front polarizer layer, a
first transparent conductive layer on a lower surface of the front polarizer layer; and
a second transparent conductive layer on an upper surface of the front transparent rigid base;
wherein the first and second transparent conductive layers are double-index matched;
a plurality of spacer bumps between the lower surface of the transparent flexible membrane and the upper surface of the rigid base,
wherein the spacer bumps are sized and positioned such that they do not obstruct an active pixel area; and
bus bars and a tail connected to the conductive layers.
2. The device of claim 1 , wherein:
the first and second transparent conductive layers comprise first and second facing films of indium tin oxide.
3. The device of claim 1 , further comprising:
a peripheral seal that, in conjunction with the lower surface of the transparent flexible membrane and upper surface of the rigid base, defines a cavity.
4. The device of claim 3 , wherein:
the cavity is filled with a transparent insulating liquid.
5. The device of claim 1 , wherein:
the transparent flexible membrane comprises:
a first and a second layer of a non-birefringent material; and the front polarizer layer, which is a layer of a linear polarizing material,
interposed between the first and second layers of non-birefringent material.
6. The device of claim 5 , wherein:
the first and second non-birefringent layers comprise cellulose triacetate.
7. The device of claim 5 , wherein:
the linear polarizing material is a poly(vinyl alcohol).
8. The device of claim 5 , wherein:
an upper surface of the first layer of non-birefringent material is coated with an
anti-reflectant material.
9. The device of claim 8 , wherein:
the upper surface of the first non-birefringent layer is coated with the anti-reflectant material before the front polarizer layer is interposed between the second non-birefringent layer and a lower surface of the first non-birefringent layer.
10. The device of claim 5 , wherein:
an upper surface of the first layer of non-birefringent material is coated with an anti-glare material.
11. The device of claim 5 , wherein:
a lower surface of the second layer of non-birefringent material is coated with a layer of indium tin oxide to provide the first transparent conductive layer.
12. The touch panel device of claim 11 wherein:
the lower surface of the second non-birefringent layer is coated with the indium tin oxide
layer before the front polarizer layer is interposed between the first non-birefringent layer and an upper surface of the second non-birefringent layer.