EMI shield filter and display apparatus having EMI shield filter

• US 6,492,587 B1
• Filed: 06/20/2000
• Issued: 12/10/2002
• Est. Priority Date: 06/21/1999
• Status: Expired due to Fees

• Current Assignee: Pioneer Corporation
• Original Assignee: NEC Corporation
• Inventors: Yoshinaga, Takashi
• Primary Examiner(s): Reichard, Dean A.
• Assistant Examiner(s): OLIVA, CARMELO B
• Application Number:
  US09/597,936
• Time in Patent Office: 903 Days
• Field of Search: 174/35.MS, 174/35.R, 361/816, 361/817, 361/818, 361/800, 348/818, 348/819, 348/820
• US Class Current: 174/350
• CPC Class Codes: H01J 11/10 AC-PDPs with at least one main electrode being out of contact with the plasma
• CPC Class Codes: H01J 11/44 Optical arrangements or shielding arrangements, e.g. filters, black matrices, light reflecting means or electromagnetic shielding means
• CPC Class Codes: H01J 2211/446 Electromagnetic shielding means; Antistatic means
• CPC Class Codes: H01J 2229/0023 Passive means
• CPC Class Codes: H01J 2229/8636 Electromagnetic shielding
• CPC Class Codes: H01J 29/868 Screens covering the input or output face of the vessel, e.g. transparent anti-static coatings, X-ray absorbing layers
• CPC Class Codes: H05K 9/0096 for television displays, e.g. plasma display panel

Abstract

An EMI (ElectroMagnetic Interference) shield filter for a display unit has a conductive mesh in which a plurality of first and second conductors are arranged in horizontal and vertical directions. A gap in one of the first and second conductors is set larger than that in the other one of the first and second conductors that attenuate a field strength of higher one of horizontal and vertical polarized components of EMI of the display unit, so that the horizontal and vertical polarized components have substantially the same field strength after attenuation. A display apparatus having this EMI shield filter is also disclosed.

Claims

1. An EMI (ElectroMagnetic Interference) shield filter for a display unit, having a conductive mesh in which a plurality of first and second conductors are arranged in horizontal and vertical directions, wherein

a first gap between each two adjacent conductors of one of said first and second conductors is set larger than a second gap between each two adjacent conductors of the other one of said first and second conductors that attenuate a field strength of a higher one of horizontal and vertical polarized components of EMI of said display unit, said first gap and said second gap being selected so that the horizontal and vertical polarized components have substantially the same field strength after attenuation,

the first gap being no greater than 50 mm.

2. A filter according to claim 1, wherein said display unit is a plasma display.

3. A filter according to claim 1, wherein the first gap is set to about three times the second gap.

4. A filter according to claim 1, wherein when said first and second conductors have a width of 15 μ

m and the second gap is 127 μ

m, the first gap is set to 381 μ

m.

5. A filter according to claim 1, wherein the first gap is set to {fraction (1/20)} to {fraction (1/100)} of a wavelength of electromagnetic radiation passing through the filter.

6. A display apparatus comprising

a housing incorporating said display unit and having an opening in a front surface thereof, and

an EMI (ElectroMagentic Interference) shield filter attached to said opening and having a conductive mesh in which a plurality of first and second conductors are arranged in horizontal and vertical directions,

wherein, in said EMI shield filter, a first gap between each two adjacent conductors of one of said first and second conductors is set larger than a second gap between each two adjacent conductors of the other one of said first and second conductors that attenuate a field strength of a higher one of horizontal and vertical polarized components of EMI of said display unit, said first gap and said second gap being selected so that the horizontal and vertical polarized components have substantially the same field strength after attenuation, the first gap being no greater than 50 mm.

7. An apparatus according to claim 6, wherein said display unit is a plasma display.

8. An apparatus according to claim 6, wherein the first gap is set to about three times the second gap.

9. An apparatus according to claim 6, wherein when said first and second conductors have a width of 15 μ

m and the second gap is 127 μ

m, the first gap is set to 381 μ

m.

10. An apparatus according to claim 6, wherein the first gap is set to {fraction (1/20)} to {fraction (1/100)} of a wavelength of electromagnetic radiation passing through said EMI shield filter.

11. An apparatus according to claim 6, wherein the horizontal and vertical polarized components after attenuation by said EMI shield filter have field strengths of not more than 50 dBμ

v/m when measured at a distance of 3 m from said display unit.