JPH0577141B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to fluorescent light emitting devices, each of which constitutes one light emitting area of a large screen display device, and which constitutes one large screen display device by combining a large number of them in a mosaic pattern. The present invention relates to fluorescent tubes, and particularly to fluorescent tubes in which the overall brightness of each individual tube can be adjusted.

[Conventional technology]

BACKGROUND OF THE INVENTION With the diversification of display devices, various types of display devices are being put into practical use or being considered, ranging from small hand-held televisions to large screen display devices with display screen areas of several to several ^tens of square meters.

Among these, large screen display devices generally use a method in which a large screen is constructed by combining a large number of fluorescent light emitting tubes, CRTs (Cathode Ray Tubes), or liquid crystal cells in a mosaic pattern.

FIG. 3 is a schematic diagram of a large screen display device of this type constructed using fluorescent light emitting tubes. 1,1 _1
1 , 1 ₁₂ , 1 ₂₁ . . . indicate individual arc tubes.
In the case of a fluorescent light emitting tube, a feature is that it is easy to form a large number of pixels within one light emitting tube. In other words, as shown in FIG.
P ₁₁ , P ₁₂ . . . m×n pixels P indicated by P _no are formed, and a larger number of arc tubes 1 are combined in a mosaic shape.

Incidentally, a fluorescent light emitting tube is basically the same as a fluorescent display tube, and the electrode structure differs depending on the driving method. One example is the electrode structure shown in FIGS. 4 and 5. In the illustrated structure, the first grid G ₁ ,
A matrix is formed using G ₁₁ , G ₁₂ and the second grid G ₂ , G ₂₁ , G ₂₂ . . . G _2o to perform pixel selection. In order to perform full-color display, the anode A consists of three anodes: an anode A _r coated with a red light-emitting phosphor, an anode A _g coated with a green light-emitting phosphor, and an anode A _b coated with a blue light-emitting phosphor. It is divided into electrodes.
The anodes A _r , A _g , and A _b are scanned cyclically at a predetermined period, and in synchronization with the scanning of the anodes, the second grid G ₂ is connected to the second grid G 2 via the second grid drive circuit 2. Display data is provided. That is, as shown in the timing chart of FIG. 6, the anodes A, _Ar , _Ag , and _Ab are cyclically scanned by the anode scanning circuit 3. On the other hand, the first grids G ₁ , G ₁₁ and G ₁₂ are selectively driven by the first grid drive circuit 4 as shown in FIG. Then, the first grid in the upper row shown in FIG.
While either _G11 or the lower first grid _G12 is selected, the display data is transferred to the second grids _G2 , _G21 , G via the second grid drive circuit 2 as shown in FIG. ₂₂ ... Upon entering G _2o , the anode A of the selected stage will emit red, green, blue or a combination thereof depending on its scanning and a display will be formed.

In FIGS. 4 and 5, K indicates a filament-shaped cathode as an electron emission source, AP indicates an anode substrate on which an anode is formed, BP indicates a rear container, and 5 indicates a cathode power source, Ek. is the cut-off bias power supply.

[Problem that the invention seeks to solve]

When combining individual light-emitting cells to form one large screen display device, in order to obtain high-quality display with no brightness variation across the screen and a uniform color mixture, the individual light-emitting cells must be uniform. It is necessary to have a certain brightness. This is no exception even when the light emitting cell is composed of a fluorescent light emitting tube. Particularly in the case of fluorescent light emitting tubes, it is unavoidable that variations occur in the distance between the electrodes or the electron emission ability of the cathode, which leads to variations in brightness.

Therefore, when considering the brightness adjustment elements for each individual fluorescent light emitting tube, we found that in Fig. 5,
First, a method of adjusting the voltage of the cathode cut-off bias power supply Ek can be considered. however,
If an attempt is made to control the brightness of the entire individual arc tube with this voltage Ek, cut-off bias power supplies Ek corresponding to the number of arc tubes making up the large screen display device will be required, which is not a good idea. In addition, the anode voltage supplied to the anode A via the anode scanning circuit 3
It is possible to adjust the overall brightness of each arc tube using Eb, but in this case, an anode terminal must be led out for each arc tube, and the number of power supplies that must be prepared also increases.

Furthermore, when adjusting the voltages of the first grid voltage E _G1 and the second grid voltage E _G2 , the number of external terminals and the number of drive circuits increase when configuring a large screen display device, similar to the above-mentioned means. cause In general, in a fluorescent light emitting tube, especially for outdoor display, the anode voltage Eb is as high as several hundred to several thousand volts, whereas the grid voltages E _G1 and E _G2 are on the order of several tens of volts. Therefore, when trying to control the brightness using the first and second grid voltages, there is a problem in that the adjustment work is difficult.

As described above, when constructing a large screen display device using fluorescent light emitting tubes, there is currently no means to appropriately adjust the overall brightness of each light emitting tube, making it difficult to obtain a high-quality large screen display. This was one of the problems.

[Means to solve problems]

The present invention has been made in view of the above-mentioned circumstances, and provides an electrically integrated brightness adjustment electrode that covers the entire light emitting part between the grid for pixel selection and the anode or cathode in the fluorescent light emitting tube. It is a composition.

[Effect]

The brightness adjustment electrode is driven by a voltage adjustment circuit. And since this brightness adjustment electrode is independent from the electrode and anode for pixel selection,
It becomes possible to drive at high voltage. In other words, the range of brightness adjustment is widened, and the adjustment work becomes easier.

Furthermore, since the brightness of the entire arc tube can be adjusted with one brightness adjustment electrode, the circuit configuration and the number of external terminals for brightness adjustment can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to screens. FIG. 1 is an exploded perspective view schematically showing an electrode structure when the present invention is applied to a type of fluorescent light emitting tube in which pixel selection is performed using two grids G ₁ and G ₂ . The same reference numerals are given to the first functional parts as in FIGS. 4 and 5. That is, cathode K
The electrons emitted from the first grid G ₁ , G ₁₁ ,
G ₁₂ and the second grid G ₂ into which the display data is input,
G ₂₁ , G ₂₂ ... are selectively accelerated or blocked by G _2o . On the other hand, the electrons selectively accelerated by the grids G ₁ and G ₂ impinge on the anodes A, Ar, Ag, and Ab, which are scanned cyclically at a predetermined period, forming pixels and forming red, red, and red pixels. It emits green, blue, or a mixture of these colors.

_G3 is a brightness adjustment electrode that is a main component of the present invention, and is an electrode that covers the light emitting area of the anode and is electrically integrated with the electrode. In terms of shape, the grid G ₁ ,
Like G ₂ , it is formed in a mesh shape. Further, although the arrangement position is between the second grid _G2 and the anode A in the embodiment shown in FIG. 1, it is not necessarily limited thereto. That is, although a fluorescent light emitting tube is basically a vacuum tube, unlike a vacuum tube for signal amplification, the amplification factor, mutual conductance, etc. are not strictly defined. Therefore, the brightness adjustment effect can be achieved even if the brightness adjustment electrode _G3 is positioned anywhere between the cathode and the anode. In order to obtain a large brightness adjustment effect, it is sufficient to place a brightness adjustment electrode _G3 between the cathode K and the first grid _G1 , but in this embodiment, the electrode G3 is placed at the position shown in the figure in consideration of the light emission state. ₃ was installed.

A brightness adjustment voltage from a brightness adjustment circuit is applied to this brightness adjustment electrode _G3 .

FIG. 2 is a schematic block diagram of a large screen display device constructed by integrating a large number of fluorescent light emitting tubes.

11, _{11 11} , 11 ₁₂ , 11 ₂₁ . . . indicate each fluorescent light emitting tube. Only the internal electrodes of the fluorescent light emitting tube ₁₁₁₁ are schematically shown, and since the others have the same structure, only blocks are shown. Each fluorescent tube 11
The cathodes of the two are commonly connected, and a driving voltage is supplied from a cathode power supply (not shown). 1st grid
The corresponding grids _G1 of all _the fluorescent light emitting tubes are connected in common and led out to the first grid drive circuit. Display data is provided to the second grid _G2 via a second grid drive circuit 13 provided for each arc tube 11.
Then, each fluorescent light emitting tube 1 is connected to the brightness adjustment electrode _G3 .
A brightness adjustment voltage E _G3 from a voltage adjustment circuit 12 provided for each brightness adjustment circuit 1 is applied.

Various circuit configurations are possible for the voltage adjustment circuit 12, but here, an npn type transistor Tr,
The base circuit is composed of a variable resistor VR and an emitter resistor R. transistor
A collector voltage E _B is applied to the collector of the Tr. By adjusting the variable resistor VR and controlling its base potential, the emitter current is varied.
Since the potential of the brightness adjustment electrode _G3 is the terminal voltage of the emitter resistor R, the potential of the electrode _G3 is controlled by adjusting the variable resistor VR.

As is clear from the schematic structural diagram shown in FIG. 1, the brightness adjustment electrode _G3 is arranged so as to completely cover the anode A. Therefore, if the potential of this electrode _G3 changes, the anode current flowing into the anode A is controlled as a whole. Since the brightness of a fluorescent tube is proportional to the anode current,
As a result, by adjusting the variable resistor VR,
The overall brightness of the fluorescent light emitting tubes 11 can be adjusted for each fluorescent light emitting tube.

In this case, since the brightness adjustment electrode _G3 is provided independently of the other electrodes, the adjustable voltage range can be set separately. That is, the power supply voltage E _B of the voltage adjustment circuit 12 is set to the highest potential in the display device,
For example, it can be made the same as the anode voltage. Therefore, the adjustable voltage range can be widened, and the work of brightness adjustment becomes extremely easy.

Furthermore, when configuring a large screen display device, the corresponding electrodes between the fluorescent light emitting tubes can be commonly connected and driven by the same power source. That is, since the brightness can be effectively adjusted without particularly increasing the number of power supplies, it is also advantageous from the standpoint of configuring a large screen display device.

In addition, in the embodiment described above, two grids are used.
Although we have described an example in which the present invention is applied to a type of fluorescent light emitting tube in which screen selection is performed using _G1 and _G2 , this invention can also be applied to a type of fluorescent light emitting tube in which pixel selection is performed by matrix driving of an anode and one grid. Of course, the present invention is applicable.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

〔effect〕

The fluorescent light emitting tube according to the present invention has a configuration including a brightness adjustment electrode between the cathode and the anode that can control the entire anode current. Therefore, by controlling the voltage externally applied to this brightness adjustment electrode, it is possible to arbitrarily adjust the overall brightness of each individual arc tube making up the large screen display device.

Therefore, for example, in the manufacturing process of fluorescent light emitting tubes,
Even if there are variations in brightness among individual arc tubes, it becomes possible to adjust the brightness after constructing a large screen display device, and uniform brightness can be obtained over the entire large screen. Particularly in the case of color display, an appropriate color mixture state can appear over the entire screen, resulting in a high-quality display.

Moreover, since this brightness adjustment electrode is controlled independently from other electrodes, the adjustable voltage range can be widened, and the brightness adjustment work can be easily performed.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the electrode structure of an embodiment of the fluorescent light emitting tube according to the present invention, and FIG. 2 is a diagram showing the electrode connection structure when a large screen display device is configured with the fluorescent light emitting tube according to the same embodiment. Figure 3 to explain
Figure 4 is a diagram for explaining a large screen display device.
FIG. 5 is a diagram for explaining a conventional fluorescent light emitting tube, and FIG. 6 is a timing diagram for explaining its driving method. 11, _{11 11} , 11 ₁₂ , 11 ₂₁ ... Fluorescent light emitting tube,
12...Voltage adjustment circuit, _G3 ...Brightness adjustment electrode.

Claims (1)

[Claims] 1. By selectively passing or blocking electrons emitted from the cathode using a plurality of grids or grids and an anode, and causing them to strike the phosphor on the anode to obtain light emission, one light-emitting area of a large screen display device can be obtained. In a fluorescent light emitting tube for forming a fluorescent light emitting tube, the fluorescent light emitting tube is disposed between the cathode and the anode, covers the entire light emitting area of the anode, and controls the flow of electrons from the cathode as a whole to control the current flowing to the anode. A fluorescent light emitting tube configured to include a brightness adjustment electrode to which an adjustable voltage is applied.