JPS60143562A - Cathode-ray tube for light source - Google Patents

Abstract

PURPOSE:To increase contrast of color emission by forming a cathode-ray tube for light source by separately arranging a phosphor screen having color emission of blue and green on the inner surface of a face comprising glass containing a specified amount of Nd2O3. CONSTITUTION:A cathode-ray tube 22 for light source is formed in such a way that a face 24 of a vacuum envelope 23 is formed with glass containing 3- 10wt% Nd2O3, and phosphor screens 25a and 25b having color emission of blue and green are separately arranged on the inner surface of the face 24 and nonfocusing electron beams 27a and 27b are irradiated from electron guns 26a and 26b to the screens for emission. The cathode-ray tubes 22 are arranged with cathode-ray tubes 21 having color emission of red and green to form a large display. Light transmission factor is improved to increase contrast and a clear image is obtained even under glaring sunlight, and also optimum visible distance is remarkably shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube for a light source used in a display device in which a large number of cathode ray tubes are arranged as pixels.

Traditionally, giant display devices used for electronic display boards in stadiums, advertising images on building roofs and walls, messages, road information displays, etc. are made by arranging a large number of light bulbs and selectively blinking them. forming an image.

In this type of light bulb, the light is obtained from the red heat of the filament of the light bulb, so the light emitted mainly has an orange or sandalwood color. For this reason, it has been quite difficult to generate large quantities of colored light, such as blue or green, from these light bulbs. Furthermore, in order to modulate the brightness of each pixel, it is necessary to turn off the applied current to the filament or to vary the applied current, but these bulbs and their frequency response are usually extremely low, less than 10 Ω. There is a problem in that the color of the emitted light itself changes depending on the applied current, making it unsuitable for displaying intermediate tones or color displays that combine light of arbitrary colors. Furthermore, such a huge display device generally requires tens to tens of thousands or more of light bulbs of about 20 to 40 W, which poses many problems in terms of power consumption and heat generation.

Therefore, the inventors have previously proposed the use of a cathode ray tube as a unit light source for the giant display device as described above. For example, red and green.

A large number of small cathode ray tubes with monochromatic fluorescent surfaces such as blue are arranged to display a desired image, and the conversion efficiency of converting electrical energy into light energy is greatly improved compared to light bulbs. It has many advantages, such as being able to emit light of any color by selecting the phosphor used. Therefore, it is advantageous when compared with the conventional light bulb system in terms of performance, reliability, maintenance cost, power consumption, etc.

FIG. 1 shows an example of the above-mentioned cathode ray tube used as a light source for a giant display device. In the figure, (1) is a vacuum envelope having a cylindrical shape, for example, for maintaining a vacuum inside the tube.

This vacuum envelope (1) has a face glass (3) on which a monochromatic fluorescent surface (2) is adhered on the inner surface of one end, and the entire surface of the fluorescent surface (2) is coated on the other end. It has an electron gun (4) for irradiating with an unfocused electron beam OQ and a terminal for applying a required voltage to each part of the electron gun (4), and is closed by a stem part (5). (6).

(7) and (8) are a heater, a cathode, and a grid, respectively, constituting the electron gun (4).

To explain the operation of this light source cathode ray tube, first,
A negative voltage with respect to the cathode (7) is applied to the grid (8) and a predetermined current is applied to the heater (6).

As a result, when the cathode (7) is heated and the voltage of the grid (8) approaches the potential of the cathode (7), an electron beam GO is emitted from the cathode (7) toward the fluorescent surface (2). . This electron beam Q4 has a predetermined spread θ determined by various conditions such as the diameter of the hole (9) provided in the center of the grid (8), the distance between the grid (8) and the cathode (7), and the anode voltage. It becomes an unfocused beam with a fluorescent surface (2
), causing the fluorescent surface (2) to emit light in a color corresponding to the fluorescent material.

Such light source cathode ray tubes are arranged regularly, with the side with the fluorescent surface facing toward you, as shown in FIG. 2, for example. Generally, this arrangement is used for green-emitting cathode ray tube α
For every two υ, one cathode ray tube (6) that emits red light and one cathode ray tube 03 that emits blue light are arranged. This is based on the fact that the resolution that governs the sharpness of an image made up of a collection of light sources is determined by the number of green pixels, and red and blue only serve as coloring. This point has been confirmed in a device actually manufactured by the inventors.

However, when arranging light source cathode ray tubes with a diameter of about 29 cm as shown in Figure 2, the structure and wiring of the socket part for supplying various voltages to the cathode ray tubes, and the waterproof structure for outdoor use, etc. Taking this into consideration, the array pitch will be approximately 40 to 46 mm, and the optimal viewing distance will be approximately ROM or more. Therefore, there is no problem in applications where long-distance viewing is the main focus, such as fan service displays at baseball stadiums, but in applications where short-distance viewing is the main focus, such as outdoor advertising, it is necessary to reduce the above-mentioned viewing distance by half or less. It is clear that

Furthermore, the phosphors used in cathode ray tubes are generally whitish in color, so when used in display devices for outdoor use, the screen becomes unclear under strong skylight in broad daylight. There is.

The present invention provides a cathode ray tube for a light source, which is suitable for use when the above-mentioned optimum viewing distance is significantly shortened, and which can realize a display device that can obtain clear images by increasing contrast even under strong sky light outdoors. It is intended to.

In order to achieve the above object, the cathode ray tube for a light source of the present invention has a fluorescent surface divided into two emission color regions of blue and green formed on the inner surface of the face portion, and a non-focusing light emitting surface in each emission color region. It is characterized in that it has two electron guns that irradiate electron beams, and that the face portion is made of glass containing 8 to 10% by weight of Nd2O3.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 shows an arrangement of light source cathode ray tubes in a display device that can shorten the optimum viewing distance. As shown in the figure, the fluorescent surface of the cathode ray tube is divided into two emission color regions, red (R) and green (G).
G) is divided into two luminescent color areas (2).

FIG. 4 shows the internal structure of the cathode ray tube 3υ, @. In the figure, the plane is a vacuum envelope, (C) is a face part, and the inner surface of this face part (C) is formed with a fluorescent surface (25a) and (25b) consisting of two regions of different luminescent colors. has been done. (26a) and (2sb) are unfocused electron beams (27a) and (2sb) with spreads of ~2 corresponding to the fluorescent surfaces (25a) and (25b) in the two regions, respectively.
7b), and this electron gun (26a)
, (26b) itself is similar to that shown in FIG. 1 above. In addition, at least the face part (goods) of the vacuum envelope (2), in the case of cathode ray tube 01), contains 8 to 10% by weight of Nd2O, and 1.5 to 5.0% by weight of Pr20B.
1.0-8.5 wt% Fe20B and 1.0-8.5 wt%
The cathode ray tube (2) is made of glass containing 8 to 11% by weight of Nd2O.

In the above display device, even if cathode ray tubes of the same size are arranged at the same pitch as in the case shown in Fig. 2, the unit light emitting surfaces are small and close together, so the optimal viewing distance of the screen is reduced by almost half. be done. Furthermore, since red and blue, which are visually most concerned about color shift, can be arranged close to each other, the display performance of composite colors such as yellow, for example, is improved, and a very easy-to-see image can be obtained.

Furthermore, since glass containing a specific component is used as the constituent material of the face portion (c) forming the fluorescent surfaces (25a) and (25b), as mentioned above, wavelength selectivity is imparted. The contrast of the emitted light color increases and a clear image can be realized.

Figure 5 shows the normal red (curve R) used in color cathode ray tubes.
), blue (curve B), and green (curve G). On the other hand, in FIG. 6, the cathode ray tube 01) whose fluorescent surface consists of two red-green light emitting regions is shown.
FIG. 7 shows the glass spectral transmittance of each face portion of a cathode ray tube (a) consisting of two emission color regions of blue and green. From Figure 6, the face of the cathode ray tube υ is
It can be seen that the light transmittance in the wavelength portion corresponding to the necessary red and green emission spectra shown in FIG. 5 is extremely good, and the light transmittance in the other wavelength portions is low. In addition, from Fig. 7, the face part of the cathode ray tube has good light transmittance in the wavelength portion corresponding to the necessary blue and green emission spectra shown in Fig. 5, and the light transmittance on the long wavelength side of curve B is good. It can be seen that the light transmittance of the hem portion and the peak wavelength portion on the longer wavelength side of curve G is low. Therefore, the contrast of each emitted light color increases, and a clear image can be obtained even under strong sky light outdoors in broad daylight.

In addition, the components contained in the glass of each face portion mentioned above, namely, Nd201, Pr2OB, Fe20B, i
If the content of CeO2 is less than the above range, the effect will not be sufficient, and if it is too much, there will be problems such as excessive light absorption, resulting in a decrease in brightness and inappropriate changes in wavelength selectivity. Furthermore, in the present invention, not only the face portion but also the entire vacuum envelope may be made of the same material.

Furthermore, for cathode ray tubes (a) whose fluorescent surface consists of two luminous color regions of blue and green, the face portion is 8 to 10% by weight.
In addition, one or both of the blue-emitting phosphor and the green-emitting phosphor may be made of pigment phosphor. In this case, even better effects can be achieved by combining the glass material of the face and the pigment phosphor.

As described above, according to the present invention, the cathode ray for the light source is suitable for use when the optimum viewing distance is significantly shortened, and has good contrast, so that it is possible to realize clear and easy-to-see images even under strong sky light. A tube is obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view showing a cathode ray tube for a light source with a monochromatic fluorescent surface, Fig. 2 is a schematic diagram showing a display arrangement of a cathode ray tube for a light source with a monochromatic fluorescent surface, and Fig. 8 is a diagram showing the invention. FIG. 4 is a schematic cross-sectional view showing an embodiment of the cathode ray tube for a light source according to the present invention, and FIG. FIG. 6 is a characteristic diagram showing the light emission characteristics of the phosphor; FIG. 6 is a characteristic diagram showing the spectral transmittance of the face of another light source cathode ray tube used in combination with the light source cathode ray tube according to the present invention; FIG. FIG. 2 is a characteristic diagram showing the spectral transmittance of the face portion of the cathode ray tube for light source according to the present invention. Qυ...A cathode ray tube for a light source whose fluorescent surface has two luminescent color regions of red and green, 4...A cathode ray tube for a light source whose fluorescent surface has two luminous color regions of blue and green, (c). ...Face part, (25a), (25b)--Fluorescent surface, (26a
), (26b) -electron gun, (27a), (27b
)...unfocused electron beam. Agent Masuo Oiwa αυ Figure 1 Figure 2 Figure 3 [Phase] O○ [Phase] ■■■

Claims (1)

[Claims] (1) A cathode ray tube for a light source used in a display device in which a large number of cathode ray tubes are arranged as pixels;
Irradiate each luminescent color region with an unfocused electron beam 2
1. A cathode ray tube for a light source, characterized in that the face portion is made of glass containing 8 to 10% by weight of Nd2O3.