Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2000-05-22
2002-10-22
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S584000, C313S586000, C313S587000
Reexamination Certificate
active
06469440
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an electromagnetic-wave shielding and light transmitting plate and a panel laminated plate of gas discharge type using a plasma display panel (hereinafter, referred to as “PDP”) and, more particularly, to an electromagnetic-wave shielding and light transmitting plate suitable for a front filter of a PDP (plasma display panel), which has good electromagnetic-wave shielding capability and near infrared ray blocking capability. The present invention also relates to a panel laminated plate in which a PDP is integrated with an electromagnetic-wave shielding and light transmitting plate to impart electromagnetic-wave shielding capability to the panel laminated plate itself, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost and, in addition, to impart near infrared ray blocking capability, thereby preventing the malfunction of a remote controller.
With the spread of electronic appliances including office apparatuses and communication instruments, electromagnetic wave emission from these appliances has come into a problem. That is, adverse effect of electromagnetic wave to the human body is feared and it is also a problem that the electromagnetic wave affects precision apparatus to cause malfunction. Therefore, plates having good electromagnetic-wave shielding efficiency and light transparency have developed as front filters for PDPs of the office automation apparatuses and come into commercial use. Such plates are also used as windows of a place where a precision apparatus is installed, such as a hospital or a laboratory in order to protect the precision apparatus from electromagnetic waves f a portable telephone.
A conventional electromagnetic-wave shielding and light transmitting plate typically comprises transparent base plates such as acrylic boards and a conductive mesh member like a wire netting and is formed by interposing the conductive mesh member between the transparent base plates and by assembling them.
The applicant of this application has proposed an electromagnetic-wave shielding and light transmitting plate, having improved characteristics and allowing easier handling as compared with the conventional one, in which a conductive mesh member is interposed between two transparent base plates and integrally bonded together by transparent adhesives (JPA 11-74683).
This electromagnetic-wave shielding and light transmitting plate has good electromagnetic shielding capability and has light transparency so that distinct pictures are displayed. Further, it has the conductive mesh member interposed between the transparent base plates, thereby preventing scattering of fragments of the transparent base panels when damaged.
On the other hand, a PDP utilizing a discharging phenomenon has the following advantages in comparison to a liquid crystal display (LCD) and a cathode ray tube (CRT). Therefore, recently it has been researched and developed for practical use, for example, televisions, office automatic apparatus such as personal computers and word processors, traffic apparatus, boards, and other kinds of display panels.
1. It utilizes discharge light so that it is spontaneous light.
2. As its discharge gap is 0.1-0.3 mm, it can be shaped in panel.
3. By using fluorescent substances, it can emit colors.
4. It eases to make wide screen.
The basic display mechanism of the PDP is displaying of letters and figures by selective discharge emitting of fluorescent substances in many discharge cells which are disposed distantly each other between two plate glasses, and for example, has a mechanism as shown in FIG.
4
.
In
FIG. 4
, a numeral
21
designates a front glass,
22
designates a rear glass,
23
designates a bulkhead,
24
designates a display cell (discharge cell),
25
designates an auxiliary cell,
26
designates a cathode,
27
designates a display anode,
28
designates an auxiliary anode. A red fluorescent substance, a green fluorescent substance, or a blue fluorescent substance (not shown) is provided in a film form on internal walls of each display cell
24
and these fluorescent substances emit light by electrical discharges when a voltage is applied between electrodes.
From the front surface of the PDP, electromagnetic waves with frequency from several kHz to several GHz are generated due to applying voltage, electrical discharge, and light emission, and the electromagnetic waves have to be shielded.
Moreover, for improving its display contrast, reflection of external light at the front surface has to be prevented.
The PDP in which the separate transparent plate is disposed in front of the PDP has defects as follows:
1. Structure for disposing two panels is complicated.
2. As a transparent base plate made of glass or the like is required for each of the PDP and the electromagnetic-wave shielding transparent plate, the PDP and the electromagnetic-wave shielding transparent plate are made thicker and heavier in total.
3. The number of parts and labor are increased, thereby raising the cost.
To solve the aforementioned problems and to provide a display panel of a panel laminated plate in which a PDP is integrally bonded to an electromagnetic-wave shielding member to impart electromagnetic-wave shielding capability to the panel laminated plate itself, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost and, further, to impart near infrared ray blocking capability in addition to the electromagnetic-wave shielding capability, the applicant of this application has previously proposed a display panel comprising a PDP body, an electromagneticwave shielding member bonded to a front surface of the PDP body by transparent adhesives, a transparent base plate bonded to a front surface of the electromagnetic-wave shielding member by transparent adhesives, which is characterized by further comprising a heat-ray blocking layer interposed between the transparent base plate and the PDP body (JPA 11-119666).
In the display panel of JPA 11-119666, the PDP, the electromagnetic-wave shielding member, the heat-ray blocking layer, and the transparent base plate are integrally bonded together by transparent adhesives, thereby lightening its weight, reducing its thickness, reducing the number of parts, and thus improving the productivity and reducing the cost. In addition, the heat-ray blocking layer is also integrally laminated on the electromagnetic-wave shielding member, thereby obtaining excellent near infrared ray blocking efficiency.
In the electromagnetic-wave shielding and light transmitting plate and the panel laminated plate, the near infrared ray blocking capability is a very-important required characteristic for the purpose of securely preventing the malfunction of a remote controller. In particular, since the producing rate of near infrared ray is increased with the improvement of brightness of PDP, further improved near infrared ray blocking capability is desired.
When an acrylic board is employed as the transparent base plate, the near infrared ray blocking capability can be imparted to the base plate just by mixing material of copper series into acrylic resin as the raw material of the base plate. However, the acrylic resin has a problem on the heat resistance, that is, the acrylic resin is poor at heat and thus may be deformed by heat. Accordingly, the acrylic resin is not preferable as the raw material of the transparent base plate of the electromagnetic-wave shielding and light transmitting plate or the panel laminated plate. Therefore, it is desired to achieve an electromagnetic-wave shielding and light transmitting plate and/or a panel laminated plate having good near infrared ray blocking capability by using glass plate having excellent heat resistance as the transparent base plate. Further, also in case of using an acrylic board, it is also desired to have improved near infrared ray blocking capability.
OB
Ono Shingo
Saito Shinji
Sugimachi Masato
Yoshikawa Masato
Berck Ken A
Bridgestone Corporation
Kanesaka & Takeuchi
Patel Vip
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