JPH0412993B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a video display terminal display device for the purpose of discharging electrostatic energy present in or generated by a user of the video display terminal device. It relates to devices that can be attached to or near the face of a surface.

[Conventional technology]

Video display terminals have now become commonplace as a result of the rapid increase in the use of computers and the like. A common display surface for such terminals is a cathode ray tube. Electromagnetic energy is generated from the terminal's internal electrical components and the cathode ray tube beam. The electromagnetic energy generates electrostatic and electromagnetic fields from the terminal device. The user of the terminal also often generates electrostatic energy from materials surrounding the terminal, the user's clothing, and the user's movements.
Such electromagnetic and electrostatic energy can be used to improve the comfort of users of the terminal, to reduce the loss of storage contents of the terminal, and to reduce damage to electronic equipment within the terminal. There is a need to remove or conduct electromagnetic and electrostatic energy from the terminal device for reasons including one of the following.

Filter screens are known. These filter screens can be positioned over the face of the video display terminal to suppress or reduce the electromagnetic and/or electrostatic fields generated by the terminal. The screen is electrically connected to the ground system of the terminal so that the electromagnetic and electrostatic fields are shunted to the ground of the terminal at the filter screen. The screen can collect static electricity generated on the terminal and direct that electrostatic energy to the terminal's ground.

The cabinet containing the terminal and the keys on the terminal's keyboard are not normally grounded to the terminal's electrical ground, but they are still connected to the electrical source of the power supply to protect the terminal's user from electrical shock. isolated from the ground. Electrostatic energy generated by a user of a terminal is not grounded to the terminal's ground simply by using the terminal's keyboard or controls. Therefore, the provision of devices that allow the user of a terminal device to discharge static electricity so as to reduce or eliminate the possibility of inconvenience to the user of the terminal device or loss of data or damage to the device. need has arisen.

[Problem to be solved by the invention]

It is an object of the present invention to provide a simple attachment to a video display terminal that allows the user of the terminal to discharge static electricity from the user to the ground of the terminal.

Another object of the invention is to provide an attachment which can be fixed to a grounded filter screen associated with the face of a video display terminal and is located at a readily accessible and easily visible location on the terminal. be.

Another object of the invention is to provide an attachment capable of being fixed to the frame of a filter screen which is grounded and is formed of a conductive material in electrical contact with the screen material of the filter screen and/or the frame of the screen. be.

Yet another object of the present invention is to visually indicate to the user that the static charge has been discharged.

[Means to solve the problem]

The present invention relates to a cathode ray tube (CRT) for displaying video, and a cathode ray tube (CRT) provided on the display surface of the CRT.
Discharging electrical charge (sometimes referred to as personal static charge) to the user of a video display terminal of the type that has a conductive mesh filter screen grounded to the display terminal to reduce or suppress the electric fields emanating from the terminal. The present invention provides a terminal device for The present invention provides a conductive contact surface at a convenient location to be electrically connected for discharge to ground through a conductive mesh filter screen. When a user touches the contact surface, the electrostatic charge on the user is safely discharged through the mesh filter.

In one embodiment of the invention, the device of the invention can be secured to the frame of the filter screen at a convenient location to provide electrical contact to the mesh filter and convenient access to the user. In another embodiment of the invention, a static charge responsive indicator light is electrically placed in the discharge path between the contact surface and the mesh filter to completely remove the static charge from the user.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings.

First, refer to FIG. In this figure, a video display terminal with a keyboard is shown in a manner typical of a computer terminal 12. The terminal device includes a cathode ray tube display 10 having a display surface 18 . The cathode ray tube 10 is the terminal device 1
It is supported inside the case 13 of No. 2 and behind the groove 15.

For purposes of this detailed description and claims, the terms "cathode ray tube" and "video display terminal" will be used herein.
The term is used to encompass the cathode ray tube itself and the associated circuitry necessary to drive the electron beam utilized within the tube to display information on the screen surface, and also includes the ground chassis. . This ground chassis may or may not include a housing for the terminal device or the like.
In summary, the term cathode ray tube (CRT)
Currently commercially available as television sets, remote displays, video display tubes, and associated circuitry used in word processors or other devices in which cathode ray tubes are used to display information electronically on the surface of the tube itself. Includes what is being done.

Reference is now made to FIG. 2 in which a radiation and static suppression device is shown in the form of a filter screen 17. The filter screen includes a conductive mesh fabric screen 14, or similarly functioning material, and a frame 16. net screen 14
positioned so that it can be aligned with the display surface of a CRT, or mounted on the front of the terminal device 12 between the user and the display surface 18;
A mesh screen 14 can be retained within the frame 16. A mesh screen so conformally mounted to reduce glare and reduce radiation and static electricity is disclosed in US Pat. No. 4,468,702. In that patent, a conductive mesh fabric coated with conductive plastic or the like is grounded to the terminal equipment ground by a ground wire 26. As shown in FIG. 3, the filter screen mesh fabric 14 is adhered to a portion 24 of the filter screen frame 16 and to a portion 28 of the ground wire 26 with a conductive adhesive.

The filter screen of the device shown in US Pat. No. 4,468,702 is effective in suppressing certain types of radiation and static electricity generated within the terminal equipment. The screen does not reduce the effects of static electricity generated by the user of the terminal or by sources external to the terminal. Static electricity can cause discomfort to the user due to the "electric shock" that is discharged to the terminal device, and can cause the contents of the terminal device's storage device to be lost.
This may cause the contents of the terminal device's storage device to be lost or the display on the terminal device's display screen to be distorted.
It is an object of the present invention to provide a means for easily, conveniently, comfortably and safely discharging static electricity.

In some video display terminals, manufacturers have placed the filter screen frame 16 in front of the groove in the face of the terminal case, or at least in the opening of the groove near the face of the CRT. Such filter screens are commonly referred to as front-mounted screens. In those positions, the frame can be approached from the front of the terminal device. The normal frame of the filter screen itself may not be conductive, but the fabric within the screen is conductive because of the coating or its construction. According to the invention, an electrical connection is made between the contact plate and the mesh of the filter screen,
A contact plate arrangement is attached to the frame of the filter screen. As shown in FIGS. 2 and 3, the contact plate 40 is connected to the frame 1 of the filter screen where a portion of the plate is in contact with the mesh 14 of the screen.
6.

4 and 5 show contact plate 40 in elevation and cross-section. As shown, the contact plate 40 is fabricated from a conductive material in a U-shape or groove shape having a body portion 42 and legs 42,46. Opposite shoulder extensions 48 are formed within the legs 42, 46 to define an inner portion 50 that is wider than the space between the extensions 48. The vertical dimension of the contact plate is substantially larger than the horizontal dimension, but the vertical dimension can be any value desired to serve the intended purpose.

The contact plate 40 is formed of a flexible material such that the legs 44 and 46 can rotate about their connection to the body portion 42. A person skilled in the art of plastics can easily select from a variety of plastics that can be used for this purpose. The extension 48 is configured to facilitate threading of the frame toward the interior 50, but to restrict removal of the frame from the interior. Additionally, an inclined surface is formed within the extension that is effective in pushing the frame firmly into the interior 50. Legs 44 or 4
The entire contact plate is made electrically conductive so that the outer edge of 6 makes good electrical contact with the mesh 14 of the filter screen.

The extension 48 encloses the frame within the interior of the legs 44 and 46 with the frame retained within the interior 50, as shown in FIGS. 2 and 3 and in detail in FIG. A contact plate 40 is configured to surround a portion of the frame 16 of the filter screen. The ends of the legs 44 or 46 contact the mesh 14 and connect the exterior of the body to the frame 1.
Expressed outside of 6. As shown in FIG.
0 is attached to the filter screen frame 16 behind the groove 15.

The user of the terminal device only needs to touch the contact plate 40 when using the terminal device for the first time or at any time during use. By touching it, the static electricity charged on the user can be discharged to the ground circuit of the terminal device through the contact plate and filter screen. If the user becomes exposed to static electricity while using the device, due to the user moving on the floor, the user's clothes rubbing against each other, or coming into contact with another source of static electricity,
Just by touching the contact plate again, the static electricity can be discharged to the ground of the terminal device.

Whether the conductive filter screen is placed in front of the display surface or in contact with the display surface,
It should be understood that the contact plate of the present invention can be attached to any type of contact plate. The contact plate of the present invention is particularly effective when the filter screen cannot be removed from the face of the display device. If a user repeatedly touches the contact plate to discharge static electricity, the screen can become dirty to the point that it is difficult to view the display. With the contact plate of the invention, only the contact plate gets dirty, so it can be removed from the frame for cleaning.

7 and 8 show another mode of operation of the contact plate of the present invention. In those figures, the contact plate 40 is mounted remotely from the frame or filter screen and is connected to the screen 14 at the face of the display surface by a conductor 60 or a pair of conductors. In FIG. 7, the screen is behind the groove 15 and the conductors are connected to the screen at the face of the display surface by suitable conductive connections. 8th
In the figure, the screen is outside the groove 15;
The conductors can be connected to the screen 14 or attached to the frame if the screen has one. In the alternative embodiment of FIGS. 7 and 8, the contact plate touches the contact plate to discharge static electricity from the user.

Figure 9 shows the screen 14 and its frame 1.
6 is mounted behind the groove 15 to show an alternative way of accessing the contact plate 40 when it is not accessible from the front of the terminal device. In this manner, the contact plate 40 is fixed to the frame as shown in FIG. 6, and the groove 15 is provided with an access hole 62 for contacting the contact plate 40. In the embodiment shown in FIG. 9, the contact plate is contacted through the access hole 62 to discharge static electricity from the user.

The device of the present invention may include an indicator light to notify the user that body static electricity has been discharged. One embodiment of such a device in a front mounted filter screen is shown in FIG. The front-mounted filter 70 is made of conductive mesh fabric 72
and a support frame 74. A conductive member 76 is disposed inside this frame. This electrically conductive member presents a contact surface 78 . The user can touch the contact surface to discharge static electricity. The electrically conductive member may be formed of carbon-filled electrically conductive nylon, for example, although it will be appreciated that other electrically conductive members may be used for this purpose as well. A viewing window 80 can also be formed in the conductive member 76. The indicator light can be seen through this display window. The conductive mesh fabric 72 can be grounded to the ground of the terminal device by a grounding cable 84.

A void is formed behind the viewing window 80 within the frame 74. In one embodiment shown in FIG.
The upper wall 86 of the cavity is formed by a portion of the conductive member 78 . The lower wall of the cavity is formed by the rear portion of the filter screen frame 74. 11, 13 and 14, the conductive mesh filter screen is designated by reference numeral 90.
It is shown in

To electrically connect conductive member 76 to indicator light 82 , conductive upper wall 86 of the cavity makes electrical contact to metal contact member 92 . The contact member 92 electrically contacts a lead 94 on a first side of the indicator light 84 . Electrical connections are made to the conductive mesh filter screen 90 via a metal plate 96 on the top of the screen. Lead 98 on the second side of indicator light 82 contacts metal plate 96 . The metal plate 96 actually makes electrical contact to the mesh with small areas rather than points.

Of course, the indicator light 82 needs to have characteristics that respond to the relatively low level of human body static electricity that charges the user. Gilway neon tubes type N501, with an ionization potential of 85 volts, have been found to be sufficient for this purpose. At neon tube lighting thresholds at or below this value, the operation of the neon tube as an electrostatic discharge indicator has been found to be independent of ambient conditions.

In this way, the indicator light is provided in the discharge path between the conductive member 76 and the conductive mesh filter section 90.
Discharging the electrical charge through the conductive mesh in this manner allows the mesh to act as a current limiting fuse in the event of an electrical problem with the CRT or ground system.

Although the present invention has been described above with reference to Examples, the present invention is not limited to these Examples. The manner of electrical connection may be varied within the spirit of the invention, such as, for example, alternative embodiments of electrical contact members or the use of conductive adhesives.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a video display terminal and related structures along with one embodiment of a filter screen to contain radiation and static electricity generated in and around the cathode ray tube of the video display terminal; FIG. 1 is a front view of the filter screen for suppressing radiation and static electricity shown in FIG. 1 with the contact plate of the present invention added, FIG. 3 is a side view of the device shown in FIG. 2, and FIG. 4 is a contact plate of the present invention. An elevational view of one embodiment of the plate; FIG. 5 is a sectional view taken along line 5-5 in FIG. 4;
6 is an assembled view showing the contact plate of FIG. 4 attached to the frame of a filter screen of a video display terminal device, FIG. 7 is a perspective view of the contact plate shown attached to the terminal device, and FIG. 8 9 is a side view showing an alternative mounting configuration of the contact plate; FIG. 9 is a partial sectional view showing access to the contact plate mounted behind the groove in the terminal device; FIG. 10 is a front mounting embodying the invention. FIG. 11 is a perspective view of the indicator light in the filter frame of the present invention; FIG. 12 is a top view of the indicator light in FIG. 11;
3 is a side sectional view of the indicator light and frame shown in FIG. 11, and FIG. 14 is a partially sectional end view of the indicator light frame shown in FIG. 11. 12... Video display terminal device, 16... Frame, 17... Filter screen, 18... Display surface, 26... Ground wire, 40... Contact plate, 42...
Body portion, 62...Access hole, 70...Front-mounted filter, 72...Conductive mesh material, 74...
Frame, 76... Conductive member, 78... Contact surface, 82... Indication light, 84... Grounding cable, 9
0... Conductive mesh filter screen, 96... Metal plate.

Claims (1)

[Claims] 1. A cathode ray tube, and a conductive device disposed within a frame that is provided above the display surface of the cathode ray tube and is grounded thereto, in order to discharge electric charges that have been charged to the user. a conductive mesh filter screen comprising a conductive mesh material; an electrically conductive member having a body portion of a predetermined length forming a contact surface for contact by the user; means for mechanically and electrically attaching the conductive member to the grounded filter screen, the body portion of the member being formed and arranged to be accessible to a user of the display terminal; Thereby, the user contacts the member at the contact surface and discharges the static charge. device to do. 2. In a method for discharging charges accumulated in a user of a video display terminal device including a cathode ray tube and a conductive mesh filter screen provided on the display surface of the cathode ray tube, the user providing an electrically conductive member having a contact surface for contacting the user; providing an indicator light that can be illuminated in response to an electrostatic discharge from the user; and providing a conductive member through the conductive mesh filter screen to ground. and a step of discharging the electric charge on the user through an indicator light and the entire mesh filter screen by contacting the contact surface. A method for discharging electrical charges accumulated on a user of a video display terminal device.