JPH0766581A - Display device - Google Patents

Abstract

PURPOSE:To well restrain unnecessary electromagnetic radiation which causes a peripheral device to malfunction even in a CRT display device provided with a CRT driving circuit of large output wide band involved in a large screen, high resolution and high picture quality. CONSTITUTION:Unwanted radiation is restrained by wrapping a signal transmitting circuit part (a signal transmitting circuit part comprised of a video amplification board 1, transmitting lines 4, 5, 6 and a socket board 33) which is a generation source of unwanted radiation in a screening shield plate 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device such as a picture tube display device which amplifies a video signal to be displayed by using a wide band amplifier and then displays the amplified video signal. To reduce unnecessary electromagnetic radiation (hereinafter sometimes simply referred to as unnecessary radiation),
The present invention relates to a display device provided with such unnecessary radiation reducing means for eliminating adverse effects such as malfunction on peripheral electronic devices or adverse effects on human body physiology.

[0002]

2. Description of the Related Art In recent years, with the increase in screen size, resolution, and image quality of picture tube display devices, picture tube drive circuits have become more and more wide-ranging in output. Especially CAD /
In a picture display device for a CAM, etc., the voltage amplitude of the drive signal is about 30V for a monochrome picture tube, about 60V for a color picture tube, and the frequency band is 50M.
Approximately Hz to 300 MHz is required.

As a result, the power consumption of the drive circuit increases, and it is necessary to cool the drive circuit by using an appropriate heat sink. Therefore, it is inevitable that the circuit components are large and heavy. Therefore, the entire drive circuit cannot be mounted on the substrate held by the neck portion due to the weight limitation in the neck portion of the picture tube. Therefore, the drive circuit
It is located near the picture tube and is connected to the picture tube neck via short interconnect signal lines.

However, in the case of transmitting a wideband signal, the unwanted radiation generated from the interconnection signal line becomes a serious problem even if the interconnection signal line has a short length. Since this unwanted radiation penetrates into an electronic device around the picture tube display device to cause a malfunction, it is necessary to reduce the unwanted radiation. A wideband picture tube drive circuit described in Japanese Patent Laid-Open No. 63-136882 taking into consideration the problem of unnecessary radiation will be described as a conventional example with reference to the configuration diagram of a picture tube display device shown in FIG.

Referring to FIG. The video amplifier board 1 and the picture tube main body 2 are composed of transmission lines 4, 5, 6 and socket boards (printed circuit boards) 3 formed by coaxial cables of R, G and B.
3 are connected. The video amplification board 1 is a wide band amplifier and is configured on a printed circuit board.
The circuit configuration includes amplifiers 7, 8, 9 for R, G, B. The socket board 33 is a connecting portion for connecting the transmission lines 4, 5, 6 and the picture tube main body 2 to each other.

In the prior art, the transmission line 4,
By grounding the outer conductors of the coaxial cables forming the cables 5 and 6, an electric field shield is provided, thereby suppressing unnecessary radiation from the transmission line when transmitting a wideband signal, and wideband and high frequency. It enables the transmission of video signals.

[0007]

Unwanted radiation emitted from a picture tube display device is regulated in each country. For example, in Japan, the Voluntary Control Council for Interference by Information Technology Equipment (commonly known as VCCI) and the United States Federal It is regulated by the Communications Commission (commonly known as the FCC). These regulations are that undesired radiation is measured at a position distant from the undesired radiation generation source by a predetermined distance, and its magnitude must not deviate from the limit value set for each predetermined frequency.

In a picture tube display device equipped with a picture tube drive circuit, which has a wider output band and a wider picture output with a larger screen, a higher resolution and a higher image quality, the above-mentioned regulation on unnecessary radiation is satisfied. It's difficult. Various factors affect the measures against unwanted radiation, and it is difficult to stabilize the characteristics. Even if the same measures are taken, the measured values will vary, so it is desirable that the regulated values can be cleared with a sufficient margin.

In view of the above, an object of the present invention is to provide a display device such as a picture tube display device provided with means capable of sufficiently suppressing unnecessary radiation.

[0010]

To achieve the above object, in the present invention, a picture tube, a socket board attached to a neck portion of the picture tube, a video amplifier board,
A display device (display device using a wide band amplifier) comprising at least a connector substrate for connecting the socket substrate and the video amplifier substrate,

The video amplifier substrate which is a heating element,
A signal transmission circuit portion formed by connecting the socket substrate attached to the neck portion of the picture tube with the connector substrate is wrapped with a shielding electromagnetic shield plate.

[0012]

As a result, the effective transmission of the signal transmission circuit portion, which is the source of the unwanted radiation, can be performed, and the unwanted radiation can be sufficiently suppressed. Further, the mechanical strength and heat dissipation efficiency of the display device are also improved by utilizing the mechanical strength and heat dissipation of the shielding electromagnetic shield plate.

[0013]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing a vertical section of a display chassis of a picture tube display device as an embodiment of the present invention.

In FIG. 1, the video amplifying substrate 1 and the picture tube body 2 are connected via the R, G, and B transmission lines 4, 5, and 6, the socket board 33, and the picture tube socket 44. . Then, the signal transmission circuit portion (the signal transmission circuit portion including the video amplification substrate 1, the transmission lines 4, 5, 6 and the socket board 33) from the video amplification substrate 1 to the neck portion of the picture tube body 2 is integrally shielded. Wrap it with the shield plate 10. Then, the integral shield shield plate 10 is fixed to the chassis 11 and 12 via fixing means 20 and 21.

The shielding shield plate 10 is made of, for example, copper, aluminum or nickel.
The shield effect is improved by using a material having higher conductivity. The fixing means 20 and 21 are typified by screws and welding, and it is necessary to make the contact area between the chassis 11 and 12 and the shielding shield plate 10 as large as possible. By fixing in this way, the high-frequency impedance between the chassis 11 and 12 and the shielding shield plate 10 can be lowered, and the emission of unnecessary radiation can be prevented.

The picture tube main body 2 is fixed to the above-mentioned chassis 11 and 12 by means of stoppers 24 and 25, and fixing means 22 and 23.
Is fixed through. The fixing means 22 and 23 are typified by screw fixing, welding, spring fixing, etc., and known fixing means can be used. Further, the shield holding member 40 is
The shield holding member 40 is fixed to the neck portion of the picture tube body 2 with a band 42, and the shield holding member 40 is used for the shielding shield plate 1 described above.
It is fixed at 0. The hole for fixing the shield holding member 40 to the shielding shield plate 10 is a hole of a size that does not cause unnecessary radiation.

As described above, the shield plate shields the signal transmission circuit portion (the signal transmission circuit portion including the video amplification substrate 1, the transmission lines 4, 5, 6 and the socket board 33) which is the source of the unwanted radiation. Wrapping with 10 can sufficiently suppress unnecessary radiation. Moreover, by having such a structure,
It is also possible to radiate the heat-generating components in the video amplification substrate 1 to the shielding shield plate 10. Shield shield plate 1
In this case, 0 also functions as a heat dissipation plate.

In FIG. 1, a shield holding member 40 is used between the neck portion of the picture tube body 2 and the shielding shield plate 10, but the neck portion of the picture tube body 2 and the shielding shield are used. It is also possible to provide a gap to the rudder plate 10 to the extent that unnecessary radiation does not pose a problem, or to insert a cushion material.

Further, in FIG. 1, the shielding shield plate 10 and the chassis 11 and 12 are fixed by using the fixing means 20 and 21, so that the heat radiation is improved. It goes without saying that heat can be radiated without fixing the cold plate 10 to the chassis 11 and 12. At this time, the shield shield plate 1 is formed by using a thick conductor such as a mesh wire.
0 and chassis 11 and 12 are connected to each other, and a high frequency impedance between the shielding shield plate 10 and the chassis 11 and 12 is connected.
It is necessary to lower the dance.

FIG. 2 is a sectional view showing a vertical cross section of a display chassis of a picture tube display device as another embodiment of the present invention. Specifically, in the embodiment shown in FIG. In this embodiment, the size of the video amplification substrate 1 is reduced to further suppress unnecessary radiation.

In FIG. 2, an output signal from a computer (not shown) or the like is transmitted through a signal cable 70 and input to the present picture tube display device. Signal case
The output terminal of the bull 70 is connected to the input terminal of the socket board 33 via the connector 71, and the video pre-IC (monolithic IC or the like) 51, the video output hybrid IC 50 and the picture tube mounted on the socket board 33. It is connected to the picture tube body 2 via the socket 44.

The video output hybrid IC 50 is attached to the shielding shield plate 10 with screws 60 for heat dissipation, and the input / output terminal of the video output hybrid IC 50 is connected to one terminal of the connector board 34. The other terminal of the substrate 34 is connected to one end of the transmission line 13,
The other end of the transmission line 13 is connected to the socket board 33.

By thus connecting the video output hybrid IC 50 and the socket board 33 via the connector board 34, the mechanical strength of the socket board 33 can be increased. The signal transmission circuit portion from the output terminal of the signal cable 70 to the neck portion of the picture tube body 2 is wrapped by an integral shield shield plate 10,
This shielding shield plate 10 is attached to the chassis 11 and 12,
It is fixed via the fixing means 20 and 21.

As described above with reference to FIG. 1, the shielding sheet
For example, copper, aluminum, nickel, or the like is used as the material of the shield plate 10, but the shield effect is improved when a material having higher conductivity is used. Fixing means 20 and 21
Is representative of screwing and welding, and it is necessary to make the contact area between the chassis 11 and 12 and the shielding shield plate 10 as large as possible.

By fixing in this manner, the high-frequency impedance between the chassis 11 and 12 and the shielding shield plate 10 can be lowered, and the emission of unwanted radiation can be prevented. The picture tube main body 2 is provided with the stoppers 24 and 25.
It is fixed to the chassis 11 and 12 via fixing means 22 and 23. The fixing means 22 and 23 are typified by screw fixing, welding, spring fixing, etc., and known fixing means can be used.

Further, the shield holding member 40 is composed of the band 4
The shield holding member 40 is fixed to the neck portion of the picture tube main body 2 at 2, and the shield holding member 40 is fixed to the shielding shield plate 10. A hole and a signal cable 7 to be opened for fixing the shield holding member 40 to the shielding shield plate 10.
0 is passed through the shielding shield plate 10 and holes through which screws for attaching the video output hybrid IC 50 to the shielding shield plate 10 are passed through the shielding shield plate 10 do not cause unnecessary radiation. The size of the hole is such that unnecessary radiation does not leak from the hole.

As described above, by using the monolithic IC and the hybrid IC for the video amplification substrate, the above-mentioned signal transmission circuit portion, which is a source of unnecessary radiation, can be downsized, and it can be further improved by enclosing it with the shielding shield plate 10. It becomes possible to effectively protect the unnecessary radiation. Further, with such a structure, it is also possible to radiate heat-radiating components such as the video output hybrid IC 50 to the shielding shield plate 10 as shown in the figure. Further, the downsizing of the signal transmission circuit section enables the downsizing of the picture tube display device.

In FIG. 2, a shield holding member 40 is used between the neck portion of the picture tube body 2 and the shielding shield plate 10, but the neck portion of the picture tube body 2 and the shielding shield 40 are used. It is also possible to provide a gap to the rudder plate 10 to the extent that unnecessary radiation does not pose a problem, or to insert a cushion material.

Further, in FIG. 2, the shielding shield plate 10 and the chassis 11 and 12 are fixed by using the fixing means 20 and 21 to enhance the heat dissipation. It goes without saying that heat can be radiated without fixing the plate 10 to the chassis 11 and 12. At this time, the shielding shield plate 10 is formed by using a thick conductor such as a mesh wire.
It is necessary to reduce the high frequency impedance between the shielding shield plate 10 and the chassis 11 and 12 by connecting the chassis 11 and 12 to the chassis 11 and 12.

According to the present embodiment shown in FIG. 2, by using the shielding shield plate 10 surrounding the signal transmission circuit portion, the heat dissipation efficiency of the signal transmission circuit portion is improved, and the shielding shield plate 10 is improved.
By further miniaturizing the portion surrounded by, it becomes possible to perform more effective shielding, and it is possible to sufficiently suppress unnecessary radiation.

FIG. 3 shows the shielding sheet in FIGS. 1 and 2.
It is a perspective view showing the appearance and structure of the cathode plate 10, and the portion where the neck portion of the picture tube is attached is the upper side. In FIG. 3, a through hole 80 for improving heat dissipation efficiency, insertion openings 81 and 82 of the shield holding member, and an insertion opening 83 of the neck portion of the picture tube can be seen. The through hole 80 needs to have a size such that unnecessary radiation does not pose a problem, and specifically, it needs to have a size not larger than 1/60 of the wavelength λ of the electromagnetic wave of unnecessary radiation. By doing so, it is possible to promote convection of air, and it is possible to improve the heat dissipation efficiency of the signal transmission circuit unit.

FIGS. 4 and 5 show an embodiment of the embodiment shown in FIGS. 1 and 2 which enables further suppression of unnecessary radiation. FIG. 4 shows a connection between the video amplifier board 1 and the socket board 33 of the picture tube display device shown in FIG. 1 by a flexible wiring board 100. The video amplifier board 1 and one end of the flexible wiring board 100 are connected to each other. Are connected by a connector 90, and the other end of the flexible wiring board 100 and the socket board 33 are connected by a connector 91.

The connectors 90 and 91 may be used as necessary. Without using the connectors 90 and 91, the flexible wiring board 100 is provided with protrusions for each signal and ground and the board of the video amplification board 1 and the board. Socket box
It goes without saying that it may be directly attached to the drive 33. The other structure is the same as that of FIG.

Further, FIG. 5 shows a connection of the input / output terminals of the video output hybrid IC 50 and the socket board 33 of the picture tube display device shown in FIG. 2 by the flexible wiring board 100. Input / output terminals of hybrid IC 50 and flexible wiring board 100
Of the flexible wiring board 100 and the socket board 33 are connected to each other by a connector 92.
Connected by.

The connector 92 may be used as needed. Without using the connector 92, the flexible wiring board 100 may be provided with protrusions for each signal and ground and be directly attached to the socket board 33. However, it goes without saying that the input / output terminal of the video output hybrid IC 50 and the flexible wiring board 100 may be connected using a connector. The other structure is the same as that of FIG.

Next, an example of a concrete structure of the flexible wiring board 100 of the embodiment shown in FIGS. 4 and 5 is shown in FIGS. 6 and 7, and further shown in FIGS. 4 and 5. The principle that enables suppression of unnecessary radiation will be described.

FIG. 6 is a sectional view of a flexible wiring board 100 usable in FIGS. 4 and 5 above. In FIG. 6, the base 110 is the bottom, and the ground planes 124 and 125 and the transmission line planes 120, 121 and 122 are alternately arranged on the surface thereof via the empty spaces 130 and 131. is there. Also, the transmission line planes 120 and 121.
And 122 are covered with an insulating layer 111,
1 and ground planes 124 and 125 are covered with a copper paste layer 126.

FIG. 7 is also a sectional view of the flexible wiring board 100 usable in FIGS. 4 and 5 above. Figure 7
The ground planes 124 and 125 and the copper paste layer 126 of FIG. 6 are removed and replaced with ground plane 127.
Are provided on the lower and left and right portions of the base material 110 and on the left and right end portions of the upper surface, and the entire flexible wiring board 100 is provided with the copper paste layer 1.
It is an example covered with 28.

The substrate 110 may be made of polyester or polyimide, or may be formed by mixing melted filament glass fiber in epoxy resin. Also, other materials may be used.

According to FIGS. 6 and 7 in the above embodiment,
By covering with the copper paste layers 126 and 128, it is possible to further suppress unnecessary radiation. In addition, close to the transmission line planes 120, 121 and 122, the ground plane 1
Since 24, 125, and 127 are arranged, the crosstalk between the transmission line planes 120 to 122 can be significantly suppressed.

Needless to say, the flexible wiring boards of FIGS. 6 and 7 described above can be used for applications other than those described with reference to FIGS. 4 and 5, that is, for all transmission lines in which unwanted radiation is a problem. .

Next, FIG. 8 shows a specific embodiment capable of improving the heat dissipation and further suppressing the unwanted radiation. Figure 8
FIG. 3 is a mounting view of the video board and the socket board of the picture tube when the picture board display device is seen through the video board and the socket board of the picture tube from the component surface of the rear video board.

In FIG. 8, the output resistors 143, 144, 145 and the video output hybrid IC 146 are symmetrically connected to the video board 147 with the video board 147 interposed therebetween, and elements such as the video pre-IC 148 are also connected. . For the output resistors 143, 144, 145, a high power metal film resistor or the like having a small size equivalent to a small power transistor and capable of adding a heat sink is used.

The output resistors 143, 144, 145 and the video output hybrid IC 146 are connected to the heat conducting means 141.
The heat conducting means 141, 142 are screwed to the shielding shield plate 140. Output resistors 143, 144, 145 and video output hybrid I
The C 146 is connected to the video board 147 by soldering or the like. This connection is the output resistance 143, 144,
The connection pins of the video output hybrid IC 145 and the video output hybrid IC 146 are not inserted into the holes of the video board 147.

With such a configuration, when the output resistors 143, 144, 145 and the video output hybrid IC 146 are attached to the heat conducting means 141, 142 with screws or the like, there is no inconvenience even if an attachment error occurs.
The output resistors 143, 144, 145 and the video output hybrid IC 146 can be connected to the video board 147, and the work process in manufacturing can be shortened. Further, the output resistance and the video output hybrid IC can be attached by soldering by hand.

Further, the signal amplified by the video board 147 is transmitted by the transmission lines 150, 151 and 152 and is transmitted to the socket board 149 of the picture tube. With such a configuration, it is possible to disperse the heat of the output resistance and the video output hybrid IC, which generate a large amount of heat, and improve the heat dissipation. With the above configuration, thermal and mechanical safety can be increased.

Further, the shielding shield plate 140 can further suppress unnecessary radiation by wrapping these constituent parts. By making the transmission lines 150, 151, 152 the flexible wiring board shown in FIG. 4 or 5,
Needless to say, it is possible to further suppress unnecessary radiation.

Next, in FIG. 9, the heat conducting means used in the embodiment shown in FIG. 8 is replaced by one heat conducting means, which can further improve heat dissipation and mechanical strength. Show. FIG. 9 is a view of the heat conducting means as viewed from the upper side (FIG. A) and the lateral side (FIG. B). In FIG. 9, a hole 161 for passing a screw or the like when attaching the heat conducting means 160 to a shielding shield or a chassis, and a hole for passing a screw or the like when attaching the output resistance to the heat conducting means. 1
A hole 163 for passing a screw or the like when the 62 and the video output hybrid IC are attached to the heat conducting means is provided.

By using the heat conducting means having such a structure, it becomes possible to increase the contact area between the heat shielding means and the shielding shield or chassis which will be the heat radiating plate. Is improved. Also, by using only one heat conducting means, the output resistance and the video output hybrid I
The mechanical strength between C, the video board and the heat conducting means is improved.

The embodiment of the present invention described above is a color picture tube display apparatus which is a picture tube display apparatus, a monochrome display or a projection tube display,
Not only monochromatic tubes used for oscilloscopes,
It is needless to say that the invention can be applied to any display device such as a plasma display panel device or a liquid crystal display panel device, and eventually to all display devices.

[0051]

As described above, according to the present invention,
With the increase in screen size, resolution, and image quality, display devices such as CRT display devices equipped with a CRT drive circuit, which has a wider output band and a wider output band, can meet the regulations regarding unnecessary radiation. There is an advantage that unnecessary radiation can be suppressed with a sufficient margin.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a vertical cross section of a display chassis of a picture tube display device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a vertical section of a display chassis of a picture tube display device as another embodiment of the present invention.

3 is a perspective view showing the appearance and structure of the shielding shield plate 10 shown in FIGS. 1 and 2. FIG.

FIG. 4 is a sectional view showing an embodiment capable of further suppressing unnecessary radiation in the embodiment shown in FIG.

5 is a cross-sectional view showing an embodiment capable of further suppressing unnecessary radiation in the embodiment shown in FIG.

FIG. 6 is a cross-sectional view showing a flexible wiring board capable of suppressing unnecessary radiation by itself.

FIG. 7 is a cross-sectional view showing another flexible wiring board that can suppress unnecessary radiation by itself.

FIG. 8 shows another embodiment of the present invention capable of suppressing unnecessary radiation and further improving the mechanical strength of the picture tube display device, in which the video board and the socket board of the picture tube are seen through from the component surface of the rear video board. It is a rear view which shows the attachment condition of the socket board of a video board and a picture tube at the time of trying.

9A and 9B are a top view and a side view showing a specific example of the heat conducting means that can be used as the heat conducting means in FIG.

FIG. 10 is a configuration diagram showing a conventional picture tube display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Video amplification board, 2 ... Picture tube main body, 10 ... Shielding shield plate, 11, 12 ... Chassis, 33, 149 ... Socket board, 4, 5, 6 ... Transmission line

Claims (9)

[Claims] 1. A picture tube, a socket board attached to a neck portion of the picture tube, a video amplifier board, and a connector board for connecting the socket board and the video amplifier board. In the display device, an electromagnetic shield plate for shielding a signal transmission circuit section formed by connecting the video amplifier board, which is a heating element, and the socket board attached to the neck portion of the picture tube by the connector board. A display device characterized by being wrapped in. 2. The display device according to claim 1, wherein the shielding electromagnetic shield plate is fixedly held on a chassis supporting the display device by using a fixing member. 3. A color picture tube, a socket board attached to a neck portion of the color picture tube, a color video amplification board, and one end thereof corresponds to R, G, B output terminals of the color video amplification board. And a transmission line for R, G, B, the other ends of which are connected correspondingly to the three electrodes for R, G, B of the socket board. In the device, a signal transmission circuit section is formed by connecting the color video amplification board and the socket board attached to the neck portion of the color picture tube by the R, G, B transmission lines. A display device characterized by being wrapped in an electromagnetic shield plate for use. 4. The display device according to claim 1, wherein by using a monolithic IC or a hybrid IC for the preamplifier section and the output amplifier section of the video amplifier board, the video amplifier board is downsized, and thus the signal transmission circuit section. A display device characterized by being downsized. 5. The display device according to claim 1, wherein among the components constituting the signal transmission circuit section, a component that generates a large amount of heat is mechanically directly connected to the shielding electromagnetic shield plate. Thus, the display device is characterized in that the heat dissipation effect of the signal transmission circuit section is enhanced by utilizing the heat dissipation effect of the shielding electromagnetic shield plate. 6. The display device according to claim 1, wherein the shielding electromagnetic shield plate enclosing the signal transmission circuit portion does not affect an electromagnetic shield action for blocking unnecessary radiation of electromagnetic waves. A display device characterized by improving the heat dissipation efficiency of the signal transmission circuit section by opening a hole having the size of 1 to allow convection of air. 7. The display device according to claim 3, wherein a flexible wiring board for signals, which has a function of blocking unnecessary radiation of electromagnetic waves by itself and has a high mechanical strength, is used for the transmission line. Characteristic display device. 8. The signal flexible wiring board according to claim 7, wherein a transmission line plane and a ground plane are provided.
By arranging them close to each other on a flexible board, covering the transmission line plane with an insulating layer, and further covering the ground plane and the transmission line plane covered with the insulating layer with a copper paste layer. The flexible wiring board for signals is characterized in that unnecessary electromagnetic radiation from the plane is prevented from leaking to the outside. 9. A picture tube, at least a socket board attached to a neck portion of the picture tube, a video amplifier board, and a transmission line connecting the socket board and the video amplifier board. In a display device in which a signal transmission circuit section formed by connecting the video amplifier board and the socket board attached to the neck portion of the picture tube by the transmission line is wrapped with a shielding electromagnetic shield plate. , And a video output hybrid IC, which is a required circuit component, and a video output hybrid IC, which are required circuit components, are symmetrically arranged with the video amplifier substrate interposed therebetween, and are connected to each other, and the output resistor is a heating element. Video output hybrid I
By connecting C and the electromagnetic shielding plate for shielding, which also functions as a heat radiating means, by using a heat conducting means, mechanical strength, heat radiating ability, and simplification of a work process at the time of manufacturing are improved. A display device characterized by.