Display with reduced parasitic effects

• US 8,384,634 B2
• Filed: 07/16/2009
• Issued: 02/26/2013
• Est. Priority Date: 09/24/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Lee, Yongman
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): Hegarty, Kelly B
• Application Number:
  US12/504,220
• Publication Number:
  US 20100073350A1
• Time in Patent Office: 1,321 Days
• Field of Search: 345 87-103, 345204-206, 345211-213
• US Class Current: 345/87
• CPC Class Codes: G02F 1/133328 Segmented frames
• CPC Class Codes: G02F 1/133331 Cover glasses
• CPC Class Codes: G02F 2201/46 Fixing elements
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: H05K 1/0237 High frequency adaptations H05K1/0216 takes precedence
• CPC Class Codes: H05K 1/162 incorporating printed capacitors
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/0792 Means against parasitic impedance; Means against eddy currents
• CPC Class Codes: H05K 2201/10136 Liquid Crystal display [LCD]

Abstract

Visual artifacts in a display are reduced by moving, to the extent possible, display driver components to the display surface itself, thereby shortening conductor distances and reducing the parasitic effects caused by parasitic resistance of the conductors between the display power supply and the display, and between the stabilizing capacitors and the display. To avoid interference with the device housing, low-profile driver components, including either or both of stabilizing capacitors and power supply terminals, can be provided and bonded to the surface of the display side of the outer layer of the display. Alternatively, the stabilizing capacitors can be formed on the display side in the same way that, e.g., in an LCD display, the transparent electrodes for controlling the liquid crystals are formed.

Claims

1. A display for an electronic device, the display comprising:

an inner layer;

a transparent outer layer having display elements mounted thereon and having a display side facing outwardly of the device; and

driver circuitry for the display elements;

wherein the driver circuitry includes at least one capacitor formed by a first trace disposed on the display side of the transparent outer layer and a second trace formed on a surface of the inner layer opposite to the outwardly facing surface of the transparent outer layer.

2. The display of claim 1 wherein:

the driver circuitry includes power supply terminals; and

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises at least one of the power supply terminals.

3. The display of claim 2 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer further comprises a sense terminal on the transparent outer layer;

the sense terminal feeds back to the driver circuitry the voltage delivered by the driver circuitry to the transparent outer layer; and

the driver circuitry adjusts its output based on the voltage fed back by the sense terminal.

4. The display of claim 2 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer further comprises a stabilizing capacitor.

5. The display of claim 4 wherein the stabilizing capacitor is a discrete capacitor bonded to the transparent outer layer.

6. The display of claim 4 wherein the stabilizing capacitor is formed on the transparent outer layer.

7. The display of claim 6 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises supply voltage wiring traces;

the driver circuitry further comprises supply voltage wiring traces mounted on a side of the inner layer opposite the display side of the transparent outer layer; and

the supply voltage wiring traces on the display side of the transparent outer layer and the supply voltage wiring traces on the side of the layer opposite the display side of the transparent outer layer are arranged opposite one another to form at least a portion of the stabilizing capacitor.

8. The display of claim 1 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises a sense terminal on the transparent outer layer;

the sense terminal feeds back to the driver circuitry the voltage delivered by the driver circuitry to the transparent outer layer; and

the driver circuitry adjusts its output based on the voltage fed back by the sense terminal.

9. The display of claim 1 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises a plurality of programmable switches and a plurality of stabilizing capacitors;

the driver circuitry comprises a plurality of voltage regulators;

the plurality of programmable switches programmably connect respective ones of the plurality of voltage regulators to respective ones of the stabilizing capacitors.

10. An electronic device comprising:

a housing;

a display mounted in said housing and including an inner layer, and a transparent outer layer having display elements mounted thereon and having a display side facing outwardly of the housing; and

driver circuitry for the display elements;

wherein the driver circuitry includes at least one capacitor formed by a first trace disposed on the display side of the transparent outer layer and a second trace formed on a surface of the inner layer opposite to the outwardly facing surface of the transparent outer layer; and

at least a portion of the driver circuitry is mounted on the display side of the transparent outer layer and is sized to avoid interfering with the housing.

11. The electronic device of claim 10 wherein:

the driver circuitry includes power supply terminals; and

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises at least one of the power supply terminals.

12. The electronic device of claim 11 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer further comprises a sense terminal on the transparent outer layer;

the sense terminal feeds back to the driver circuitry the voltage delivered by the driver circuitry to the transparent outer layer; and

the driver circuitry adjusts its output based on the voltage fed back by the sense terminal.

13. The electronic device of claim 11 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer further comprises a stabilizing capacitor.

14. The electronic device of claim 13 wherein the stabilizing capacitor is a discrete capacitor bonded to the transparent outer layer.

15. The electronic device of claim 13 wherein the stabilizing capacitor is formed on the transparent outer layer.

16. The electronic device of claim 15 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises supply voltage wiring traces;

the driver circuitry further comprises supply voltage wiring traces mounted on a side of the inner layer opposite the display side of the transparent outer layer; and

the supply voltage wiring traces on the display side of the transparent outer layer and the supply voltage wiring traces on the side of the inner layer opposite the display side of the transparent outer layer are arranged opposite one another to form at least a portion of the stabilizing capacitor.

17. The electronic device of claim 10 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises a sense terminal on the transparent outer layer;

the sense terminal feeds back to the driver circuitry the voltage delivered by the driver circuitry to the transparent outer layer; and

the driver circuitry adjusts its output based on the voltage fed back by the sense terminal.

18. The electronic device of claim 10 wherein:

the at least a portion of the driver circuitry that is mounted on the display side of the transparent outer layer comprises a plurality of programmable switches and a plurality of stabilizing capacitors;

the driver circuitry comprises a plurality of voltage regulators;

the plurality of programmable switches programmably connect respective ones of the plurality of voltage regulators to respective ones of the stabilizing capacitors.

19. A method of forming a display for an electronic device so as to reduce parasitic artifacts on the display, wherein the display has (a) an inner layer, and a transparent outer layer having display elements mounted thereon and having a display side facing outwardly of the device, and (b) driver circuitry for the display elements;

the method comprising;

providing at least one capacitor formed by a first trace disposed on the display side of the transparent outer layer and a second trace formed on a surface of the inner layer opposite to the outwardly facing surface of the transparent outer layer;

providing, at least partly on the display side of the transparent outer layer, stabilizing capacitors;

providing, on the display side of the transparent outer layer, terminals for connecting supply voltages from the driver circuitry to the display elements; and

providing, on the display side of the transparent outer layer, programmable switches for programmably connecting respective ones of the terminals to respective ones of the stabilizing capacitors;

whereby;

the supply voltages are selectably connectable to respective ones of the stabilizing capacitors.

20. The method of claim 19 wherein providing stabilizing capacitors at least partly on the display side of the transparent outer layer comprises bonding discrete capacitors to the transparent outer layer.

21. The method of claim 19 wherein providing stabilizing capacitors at least partly on the display side of the transparent outer layer comprises forming capacitors at least partly on the transparent outer layer.

22. The method of claim 21 wherein forming capacitors at least partly on the transparent outer layer comprises forming, on a side of the inner layer opposite the display side of the transparent outer layer, first conductors opposite second conductors on the display side of the transparent outer layer, and using the first and second conductors as conductors and as a capacitor.

23. A method of operating a display for an electronic device so as to reduce parasitic artifacts on the display, wherein the display has (a) an inner layer, and a transparent outer layer having display elements mounted thereon and having a display side facing outwardly of the device, and (b) driver circuitry for the display elements including, on the display side of the transparent outer layer, (a) stabilizing capacitors, (b) terminals for connecting supply voltages from the driver circuitry to the display elements, (c) programmable switches for programmably connecting respective ones of the terminals to respective ones of the stabilizing capacitors;

and (d) at least one capacitor formed by a first trace disposed on the display side of the transparent outer layer and a second trace formed on a surface of the inner layer opposite to the outwardly facing surface of the transparent outer layer, the method comprising;

operating the programmable switches to apply respective supply voltages of the driver circuitry to respective ones of the stabilizing capacitors.