Methods and systems of vibrating a screen
Screen vibration systems are provided that can vibrate theatre screens while reducing the presence of image artifacts that may otherwise be visible as result of vibrating the screen. In one example of a screen vibration system, the system includes a screen, a permanent magnet mounted to the screen, and a magnetic source positioned with respect to the permanent magnet. The screen is moveable in response to a changing magnetic field from the magnetic source.
1. A screen vibration system, comprising:
a screen;
a permanent magnet mountable to the screen; and
a magnetic source positionable proximate to the permanent magnet and uncoupled from the screen,
wherein the screen is moveable at least one of inward or outward, in response to a changing magnetic field from the magnetic source, such that a displacement of the screen is configured to be greater at a first location to which the permanent magnet is mountable to the screen as compared to the displacement of the screen at a second location that is different than the first location.
2. The screen vibration system of claim 1 , wherein the magnetic source is an electromagnet that is controllable by an electrical current for generating the changing magnetic field.
3. The screen vibration system of claim 2 , wherein the electromagnet and the permanent magnet are configured to form a closed loop for a path of the changing magnetic field.
4. The screen vibration system of claim 2 , further comprising a controller configured to control the electrical current that is an asymmetrical-changing electrical current for causing the changing magnetic field to be asymmetrical, wherein the screen vibration system is configured to determine the asymmetrical-changing electrical current by adjusting an amount of direct current bias to an electrical current signal provided to the electromagnet from the controller.
5. The screen vibration system of claim 1 , wherein the magnetic source includes a second permanent magnet configured for generating the changing magnetic field, wherein the magnetic source further includes:
a motor shaft configured to couple to the second permanent magnet; and
a motor configured to rotate the motor shaft to cause the second permanent magnet to rotate.
6. The screen vibration system of claim 1 , further comprising:
a stiff material configured for mounting to the permanent magnet and for mounting to the screen,
wherein the permanent magnet is mountable to the screen through the stiff material.
7. The screen vibration system of claim 6 , wherein the stiff material is a batten that is made from a material that includes at least one of balsa wood, carbon fiber, or a composite material.
8. The screen vibration system of claim 7 , wherein the batten is mountable to the screen using an adhesive.
9. The screen vibration system of claim 1 , wherein the permanent magnet includes a first end having a first magnet pole and a second end having a second magnetic pole,
wherein the magnetic source has a first outer boundary and a second outer boundary, and
wherein the magnetic source and the permanent magnet are positionable with respect to each other such that (i) a gap is formed between the magnetic source and each of the first end and the second end, (ii) the first outer boundary aligns with the first end or aligns to an area between the first end and the second end, and (iii) the second outer boundary aligns with the second end or to an area between the first end and the second end.
10. A method to vibrate a screen, the method comprising:
mounting a permanent magnet onto the screen;
positioning a magnetic source proximate to the permanent magnet and uncoupled from the screen; and
controlling the magnetic source to successively repel and attract the permanent magnet to cause the screen to vibrate by moving the screen at least one of inward or outward such that a displacement of the screen is greater at a first location to which the permanent magnet is mounted to the screen as compared to the displacement of the screen at a second location that is different than the first location.
11. The method of claim 10 , wherein the magnetic source is an electromagnet, wherein controlling the magnetic source to successively repel and attract the permanent magnet to cause the screen to vibrate comprises:
controlling an electronic current to the electromagnet.
12. The method of claim 11 , wherein controlling the electronic current to the electromagnet comprises causing the electromagnet to repel the permanent magnet by a distance that is equal to the distance by which the electromagnet attracts the permanent magnet.
13. The method of claim 11 , wherein controlling the electrical current to the electromagnet includes controlling the electrical current so that a position determined from an average displacement of the permanent magnet corresponds to a rest position of the permanent magnet.
14. The method of claim 11 , wherein the electrical current has a frequency that is random.
15. The method of claim 10 , wherein the magnetic source includes a second permanent magnet that generates a changing magnetic field to successively repel and attract the permanent magnet to cause the screen to vibrate.
16. The method of claim 10 , wherein mounting the permanent magnet onto the screen comprises:
mounting the permanent magnet to a stiff material; and
mounting the stiff material to the screen such that the permanent magnet is mounted to the screen indirectly through the stiff material.
17. The method of claim 16 , wherein the stiff material is a batten that is made from a material that includes at least one of balsa wood, carbon fiber, or a composite material.
18. The method of claim 17 , wherein mounting the batten to the screen comprises mounting the batten to the screen using an adhesive.
19. The method of claim 10 , wherein the permanent magnet includes a first end having a first magnet pole and a second end having a second magnetic pole,
wherein the magnetic source has a first outer boundary and a second outer boundary, and
wherein positioning the magnetic source proximate to the permanent magnet comprises:
positioning the magnetic source such that (i) the first outer boundary aligns with the first end or aligns to an area between the first end and the second end, and (ii) the second outer boundary aligns with the second end or to an area between the first end and the second end; and
forming a gap between the magnetic source and each of the first end and the second end.
20. A system, comprising:
a permanent magnet mountable to a screen in a theatre; and
a magnetic source that is positionable proximate to the permanent magnet and uncoupled to the screen, the magnetic source being configured to output a changing magnetic field for moving the screen at least one of inward or outward such that a displacement of the screen is greater at a first location to which the permanent magnet is mountable to the screen as compared to the displacement of the screen at a second location that is different than the first location.
21. The system of claim 20 , further comprising a controller configured to couple to the magnetic source for controlling the magnetic source in outputting the changing magnetic field, wherein the magnetic source is a stationary electromagnet that is controllable by an electrical current from the controller for generating the changing magnetic field.
22. The system of claim 21 , wherein the electrical current from the controller is an asymmetrical-changing electrical current for causing the changing magnetic field to be asymmetrical.
23. The system of claim 21 , wherein the magnetic source is a second permanent magnet, and
wherein the controller is configured to cause the second permanent magnet to rotate for generating the changing magnetic field.
24. The system of claim 20 , further comprising:
a stiff material configured for mounting to the permanent magnet and for mounting to the screen,
wherein the permanent magnet is mountable to the screen through the stiff material.
25. The system of claim 24 , wherein the stiff material is a batten that is made from a material that includes at least one of balsa wood, carbon fiber, or a composite material.
26. The system of claim 25 , wherein the batten is mountable to the screen using an adhesive.
27. The system of claim 20 , wherein the permanent magnet includes a first end having a first magnet pole and a second end having a second magnetic pole,
wherein the magnetic source has a first outer boundary and a second outer boundary, and
wherein the magnetic source and the permanent magnet are positionable with respect to each other such that (i) a gap is formed between the magnetic source and each of the first end and the second end, (ii) the first outer boundary aligns with the first end or aligns to an area between the first end and the second end, and (iii) the second outer boundary aligns with the second end or to an area between the first end and the second end.