Stock material or miscellaneous articles – Composite – Of quartz or glass
Reexamination Certificate
1999-01-29
2002-07-02
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of quartz or glass
C428S216000, C428S433000, C428S434000, C428S472000, C428S701000, C428S702000, C428S699000, C359S360000, C359S585000, C359S589000
Reexamination Certificate
active
06413643
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to a sunlight shielding translucent glass panel having a multilayer film structure including a film composed mainly of silver (Ag), and a sunlight shielding translucent multilayer glass panel assembly which includes such a sunlight-shielding translucent glass panel.
2. Description of the Related Art:
Recent years have seen widespread use of multilayer window glass panes to meet growing demands for highly air-tight, thermally insulated houses. For the purpose of increasing thermal insulating performance and sunlight shielding performance, multilayer glass panes using a glass sheet which has a multilayer film structure including a film composed mainly of Ag are also finding popular use. If multilayer glass panes using a glass sheet which has a multilayer film structure including a mainly Ag film are employed as window glass panes, then the windows have improved thermal insulating performance and sunlight shielding performance. The improved thermal insulating performance cuts down on the cost of heating the house in winter-time, and the improved sunlight shielding performance reduces the cost of cooling the house in summertime.
On conventional glass panel having a multilayer film structure including a mainly Ag film is disclosed in Japanese patent publication No. 7-15143, for example. As shown in
FIG. 1
of the accompanying drawings, the disclosed glass panel comprises a transparent glass sheet
11
, a first transparent dielectric film
13
disposed on the transparent glass sheet
11
, a mainly Ag film
15
disposed on the first transparent dielectric film
13
, and a second transparent dielectric film
17
disposed on the mainly Ag film
15
. A multilayer film structure composed of the three films
13
,
15
,
17
will be referred to as a single-Ag-layer LowE film structure.
Another known glass panel having a multilayer film structure including mainly Ag films is also disclosed in Japanese patent publication No. 7-165442. As shown in
FIG. 2
of the accompanying drawings, the disclosed glass panel comprises a transparent glass sheet
11
, a first transparent dielectric film
13
disposed on the transparent glass sheet
11
, a first mainly Ag film
15
disposed on the first transparent dielectric film
13
, a second transparent dielectric film
17
disposed on the first mainly Ag film
15
, a second mainly Ag film
19
disposed on the second transparent dielectric film
17
, and a third transparent dielectric film
21
disposed on the second mainly Ag film
19
. A multilayer film structure composed of the five films
13
,
15
,
17
,
19
,
21
will be referred to as a double-Ag-layer LowE film structure.
Still another known glass panel having a multilayer film structure including mainly Ag films is disclosed in Japanese patent publication No. 7-149545. As shown in
FIG. 3
of the accompanying drawings, the disclosed glass panel comprises a transparent glass sheet
11
, a first transparent dielectric film
13
disposed on the transparent glass sheet
11
, a first mainly Ag film
15
disposed on the first transparent dielectric film
13
, a second transparent dielectric film
17
disposed on the mainly Ag film
15
, a second mainly Ag film
19
disposed on the second transparent dielectric film
17
, a third transparent dielectric film
21
disposed on the second mainly Ag film
19
, a third mainly Ag film
23
disposed on the third transparent dielectric film
21
, and a fourth transparent dielectric film
25
disposed on the third mainly Ag film
23
. A multilayer film structure composed of the seven films
13
,
15
,
17
,
19
,
21
,
23
,
25
will be referred to as a triple-Ag-layer LowE film structure.
A comparison between the double-Ag-layer LowE film structure and the single-Ag-layer LowE film structure which have the same visible light transmittance indicates that the double-Ag-layer LowE film structure is better than the single-Ag-layer LowE film structure with respect to the sunlight shielding performance. Therefore, a window glass pane which comprises a multilayer glass pane that employs the glass panel with the double-Ag-layer LowE film structure is more effective in suppressing a rise in the indoor temperature than a window glass pane which comprises a multilayer glass pane that employs the glass panel with the single-Ag-layer LowE film structure, whereas both window glass panels ensure substantially the same indoor lightness during the daytime.
A comparison between the triple-Ag-layer LowE film structure and the double-Ag-layer LowE film structure which have the same visible light transmittance indicates that the triple-Ag-layer LowE film structure is better than the double-Ag-layer LowE film structure with respect to the sunlight shielding performance. A window glass pane which comprises a multilayer glass pane that employs the glass panel with the triple-Ag-layer LowE film structure is more effective in suppressing a sunlight-induced rise in the indoor temperature while keeping the room light during the daytime, and also in reducing the load on the air-conditioning unit, than a window glass pane which comprises a multilayer glass pane that employs the glass panel with the double-Ag-layer LowE film structure.
However, the double-Ag-layer LowE film structure is more expensive than the single-Ag-layer LowE film structure as the former has more films than the latter. Similarly, the triple-Ag-layer LowE film structure is more expensive than the double-Ag-layer LowE film structure as the former has more films than the latter.
To make buildings an energy saver, a higher priority is usually given to efforts to reduce the load on the air-conditioning system than to improving the thermal insulating capability. For reducing the air-conditioning system load, there have been widely used heat reflecting glass panels which include one or more layers of a metal oxide, a metal, and a metal nitride on a transparent glass sheet. Such conventional heat reflecting glass panels are highly effective to reduce the air-conditioning system load because they has as good sunlight shielding performance as the triple-Ag-layer LowE film structure.
The sunlight shielding performance of each of the glass panel with the single-Ag-layer LowE film structure and the glass panel with the double-Ag -layer LowE film structure is poorer than the sunlight shielding performance of the conventional heat reflecting glass panels. Therefore, when a multilayer glass pane using a glass panel with the single-Ag-layer LowE film structure or double-Ag-layer LowE film structure are employed as window glass panes, a sunlight-induced rise in the indoor temperature is higher than it is when a heat reflecting glass panel is used as a window glass pane. From the standpoint of the sunlight shielding performance, therefore, it is preferable to use a heat reflecting glass panel as a window glass pane.
However, the visible light transmittance of a heat reflecting glass panel is much lower than the visible light transmittance of a glass panel with the single-Ag-layer LowE film structure, the double-Ag-layer LowE film structure, or the triple-Ag-layer LowE film structure. Therefore, when a heat reflecting glass panel is employed as a window glass pane, the interior room is relatively dark in the daytime, and the window glass pane looks unnatural.
There have already known heat reflecting glass panels that are designed to solve the above problems by reducing the thickness of a metal or metal oxide film for higher visible light transmittance. However, these heat reflecting glass panels with such higher visible light transmittance are necessarily poor in sunlight shielding performance.
The sunlight shielding performance of glass panels with the triple-Ag-layer LowE film structure is of substantially the same level as the sunlight shielding performance of heat reflecting glass panels. However, the glass panels with the triple-Ag-layer LowE film structure are highly expensive to manufacture because of the large number of films, i.e., seven films,
Arai Daisuke
Kunisada Terufusa
Ogino Etsuo
Jones Deborah
McNeil Jennifer
Nipon Sheet Glass Co., Ltd
Schwegman Lundberg Woessner & Kluth P.A.
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