JPH0362274B2 - - Google Patents

Description

[Detailed description of the invention]

[Objective of the Invention] (Industrial Application Field) The present invention consists of one picture element made up of discharge elements that emit red, blue, and green colors, and a large number of these picture elements are arranged side by side, and each picture The present invention relates to a large-sized color image display device that displays images by changing the luminance of discharge tubes constituting the element. (Prior Art) Generally, in a large color image display device, the state in which the picture elements emit white light, that is, the state of white balance, is the maximum brightness of each discharge tube in the display device. Conventionally, various methods have been used to obtain white balance. First, there is a method in which the light emitting area of the discharge tube is made different for each emitted color. However, in this case, since the structure of the discharge tube is different, problems occur in manufacturing and in terms of picture elements, and color mixing also worsens, resulting in poor display visibility. There are also models with different power supply voltages. However, in this case, the drop in power supply voltage makes it difficult to start the discharge tube. Furthermore, there are also known devices in which the pulse width is controlled to change the pause period of one cycle. However, in this case, since the pulse width becomes narrow, the division ratio when dividing the pulse width and controlling the light becomes poor. (Problems to be Solved by the Invention) As mentioned above, if the light emitting area of the discharge tube is made different for each light emitting white, problems will arise in terms of manufacturing and pixel filling, as well as the color mixture will worsen and the visibility of the display will deteriorate. I have a problem. Further, when the power supply voltage is changed, there is a problem in that the discharge tube becomes difficult to start due to a decrease in the power supply voltage. Furthermore, if the pulse width is controlled and the rest period of one cycle is changed, the pulse width becomes narrower, so there is a problem in that the division ratio becomes poor when the pulse width is divided for dimming. The present invention has been developed in view of the above-mentioned problems, and is easy to manufacture and fill and arrange in picture elements, does not deteriorate visibility, can be started reliably, and also prevents a decrease in the division ratio of dimming. The purpose of the present invention is to provide a large-sized color image display device that is capable of displaying large-sized color images. [Structure of the Invention] (Means for Solving the Problems) The large color image display device of the present invention has red, blue,
In a large color image display device in which a plurality of green fluorescent discharge elements form one picture element, and a display surface is constructed by arranging a plurality of these picture elements, red, blue, and green signals are transmitted. an image processing device that converts the image signal into an image signal; a DC power supply device that supplies a voltage and has a switching element and a pulse width controller that controls the conduction time of the switching element based on the image signal of the image processing device; a display control device that controls an output of the DC power supply device that applies an image signal from a processing device to a predetermined fluorescent discharge element of a predetermined picture element; and a brightness ratio of the fluorescent discharge element is red; 34.3%; -22.5% Blue; 4.9% - 16.3% Green; 60.8% - 61.2%. (Operation) According to the present invention, an image processing device converts red, blue, and green signals into image signals. The voltage of the DC power supply is applied to a predetermined fluorescent discharge element of a predetermined picture element, the pulse width controller controls the conduction time of the switching element based on the image signal, and the display controller applies the voltage of the DC power supply to a predetermined fluorescent discharge element of a predetermined picture element. control. In the current limiting element, the brightness ratio of the red fluorescent discharge element is 34.3% to 22.5%, the brightness ratio of the blue fluorescent discharge element is 4.9% to 16.3%, and the brightness ratio of the green fluorescent discharge element is 60.8%. ~61.2%,
Each picture element is lit to project an image on the display screen. (Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the display section of a large color image display device, in which the display surface 1 has three discharge tubes 3R coated with phosphors emitting light of different colors, red, blue, and edges. , 3B, and 3G are arranged. These discharge tubes 3R,
3B and 3G are all formed to have the same size and shape. In addition, as shown in FIGS. 2 and 3, the shape of all of these discharge tubes 3 is such that the center portion of the tube body 4 is bent into a substantially U-shape, and the base portions 5 at both ends are bent toward the display surface.
These caps 5 are inserted into and supported by sockets 6 located at the back. FIG. 4 is a block diagram showing the structure of the display device. 11 is a video tape recorder (VTR), and this video tape recorder 11 has a receiving antenna 1.
The tuner 13 converts the television signal received by the TV signal into a video signal, inputs it, and stores it, and also inputs and records the video signal directly from the camera 14, outputs the recorded video signal, and outputs the image. input to the processing device 15; The image processing device 15 samples a video signal, which is an analog signal corresponding to red, blue, and green, output from the video tape recorder 11 based on a sampling signal, converts it into a digital image signal, and outputs the digital image signal. Input to display control device 16. The display control device 16 controls the image signal from the image processing device 15 so that it can be applied to a predetermined discharge tube 3 of a predetermined picture element 2 . Further, 17 is a lighting device, and this lighting device 17 is provided corresponding to a discharge tube, for example, red 3R, and performs pulse width modulation on the voltage supplied from the DC power supply device 18 based on the image signal to control dimming. In the three red, blue, and green discharge tubes 3R, 3B, and 3G in each picture element 2, the impedance value of each current-limiting circuit 19, which is a current-limiting element, is different. Furthermore, the configuration of this lighting device 17 will be explained with reference to FIG. Reference numeral 21 denotes a main power source of the DC power supply 18. A push-pull type inverter circuit 23 is connected to the main power source 21 via a dimmer 22, and a current limiting circuit made of an inductance is connected to the output end of the inverter circuit 23. The discharge tube 3 is connected via 19. Further, a filament power supply 25 of a DC power supply device 18 is connected to the filament 24 of the discharge tube 3. The dimmer 22 is a switching transistor 2
6, and a pulse width controller 27 which outputs a pulse width modulated signal based on the image signal input from the terminal a and controls the conduction time of the transistor 26. In addition, the inverter circuit 23 is connected to the constant current reactor 2
8, switching transistors 29, 30,
It is composed of feedback resistors 31 and 32, a capacitor 33, and an inverter transformer 34. The configuration of this lighting device 17 is the same for all the fluorescent lamps 3 of all the picture elements 2, but the impedance value of the inductance of the current limiting circuit 19 is different from the discharge of red, blue, and green, which emit different colors. tube 3
R, 3B, and 3G are different, and the lamp current I _L supplied from the inverter circuit 23 is changed. Next, the operation of this embodiment will be explained. For example, the phosphors of the discharge tubes 3R, 3B, and 3G of each color are Y ₂ O ₃ :Eu for red, Y ₂ SiO ₅ :Ce.Tb for blue,
When green is 3 (Sr.Eu) OP ₂ O ₅ CaCl.B ₂ O ₃ , the inductance of the current limiting circuit 19 is varied according to the discharge tubes 3R, 3B, and 3G of each color to adjust the lamp current I _L The table below shows the brightness ratio and color temperature when mixed when changing. In addition, each discharge tube 3R, 3B, 3G at this time has a tube diameter of 14.5φmm and an effective lamp length.
At 70 mm, the fill gas is mercury and an inert gas such as argon.

〔Effect of the invention〕

According to the present invention, in order to balance the white color of discharge tubes that emit different colors of red, blue, and green, the impedance values of the current-limiting elements to each discharge tube are made different. It is possible to improve the workability of filling and arranging the material, and visibility is not adversely affected. In addition, since there is no need to reduce the voltage supplied to the discharge tube, problems with starting the discharge tube can be avoided.
Furthermore, since white balance can be obtained with the power supply pulse being fully conductive to the discharge tube, it is possible to avoid problems such as a reduction in the number of dimming divisions unless the accuracy of the pulse width controller is improved, which also improves cost efficiency. It is something that can be improved.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of a large color image display device of the present invention, FIG. 2 is a front view showing one picture element, FIG. 3 is a side view of a fluorescent lamp, and FIG. FIG. 5 is a block diagram of a large color image display device and a circuit diagram of a lighting device. DESCRIPTION OF SYMBOLS 1...Display surface, 2...Picture element, 3...Discharge tube as a fluorescent discharge element, 15...Image processing device, 16
... Display control device, 18 ... DC power supply device, 19
... Current limiting circuit as a current limiting element, 26... Transistor as a switching element, 27... Pulse width controller.

Claims (1)

[Claims] 1. A large color image display in which a plurality of red, blue, and green fluorescent discharge elements form one picture element, and a display surface is constructed by arranging a plurality of these picture elements. The apparatus includes an image processing device that converts red, blue, and green signals into image signals, a switching element, and a pulse width controller that controls the conduction time of the switching element based on the image signal of the image processing device. a DC power supply device that supplies voltage; a display control device that controls the output of the DC power supply device that applies an image signal from the image processing device to a predetermined fluorescent discharge element of a predetermined picture element; A current limiting element having an impedance value set such that the luminance ratio of the photodischarge element is 34.3% to 22.5% for red, 4.9% to 16.3% for green, and 60.8% to 61.2% for green. Large color image display device.