JPH04298946A - Display tube for light source - Google Patents

Abstract

PURPOSE:To increase the intensity of a luminescence face by forming the inner face of a front panel into an irregular shape. CONSTITUTION:Portions on the inner face of a front panel 2 where luminescence face 5 is formed are protruded, and the practical surface area is increased without changing the area of the face when a display tube for a light source is seen from the front. High-temperature melted glass is filled into a molding die made of a carbon material with the desired shape then cooled to manufacture the panel 2, or the molding die made of the carbon material is pressed to a plate glass, and they are heated in a high-temperature furnace to manufacture the panel 2. Phosphors are coated to the proper thickness at the preset position on the inner face of the panel 2 to form the luminescence face 5. The luminescence area can be increased without changing the apparent luminescence area, and the intensity of the luminescence face 5 can be increased without changing the radiation intensity of an electron beam per unit surface area on the luminescence face 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display tube for a light source used in displays such as large-screen display devices and message boards.

0002

2. Description of the Related Art Currently, large-screen display devices consisting of a large number of display tubes for light sources are used outdoors, for example.
8 meters long and 10 meters long, and even indoors 4 meters wide and 3 meters long, have been put into practical use. The light source display tube used in this large screen display device has a power output of approximately 4000 cd when used outdoors.
/m2, and even indoors requires high brightness of about 1000 cd/m2. As a display tube for a light source that can generate such high brightness, there is one disclosed in Japanese Patent Laid-Open No. 10849/1983. Here, red color (hereinafter abbreviated as R)
, a light-emitting surface coated with phosphors that emit blue (hereinafter abbreviated as B) and green (hereinafter abbreviated as G) is arranged in three vertical directions.
A description will be given of a matrix arranged in rows and three columns in the horizontal direction.

FIG. 5 is a sectional view showing the basic structure of a conventional light source display tube, and FIG. 6 is a partially exploded perspective view of the light source display tube. In the figure, 1 is a glass tube which is a vacuum envelope composed of a front panel 2, a back panel 3, and a cylindrical side plate 4, and 5 is a glass tube arranged inside the glass tube 1 of the front panel 2. When the beam 13 is irradiated, R
, G, and B are light emitting surfaces coated with emitting phosphors, respectively; 6 surrounds the periphery of the light emitting surface 5 and is arranged perpendicularly to the front panel 2, and is used for accelerating the electron beam 13 to guide it to the light emitting surface 5. The anode electrode 7 is a cathode electrode disposed on the back panel 3 corresponding to the light emitting surface 5, and is a linear cathode 7a for emitting electron beams, which is made of linear tungsten coated with oxide. and a pair of metal supports 7b that fix both ends to the back plate 3. Reference numeral 8 denotes a control grid electrode for row selection disposed between the cathode electrode 7 and the light emitting surface 5, which controls the electron beam 13 emitted from the cathode electrode 7.
An electron beam passage hole 9, which is an opening for passing the electron beam, is provided at a position facing the cathode electrode 7. 10
1 is a striped column selection back electrode provided inside the glass tube 1 of the back panel 3 under the cathode electrode 7; 11 is the back electrode 10, the cathode electrode 7, and the control grid; an external terminal for applying a driving voltage to the electrode 8;
12 is an external terminal for applying a high voltage to the acceleration anode electrode 6.

The light source display tube constructed as described above operates as follows. A voltage is applied to the cathode electrode 7,
When the linear cathode 7a is heated to about 700 to 750 degrees Celsius, thermoelectrons are emitted. At this time, the cathode electrode 7
When a suitable positive potential is applied to the back electrode 10 and the control grid electrode 8 with respect to the potential of the cathode electrode 7, the potential around the cathode electrode 7 becomes positive. At this time, a high voltage is applied to the anode electrode 6, and the potential gradient has a positive gradient toward the anode electrode 6, and the electrons emitted from the cathode 7a follow this potential gradient. The unfocused electron beam 13 is accelerated by the high voltage of the anode electrode 6 and collides with the light emitting surface 5 at high speed, causing the light emitting surface 5 to emit light with high brightness. Further, if the potential of both the back electrode 10 and the control grid electrode 8, or the potential of either one of them, becomes a negative level with respect to the potential of the cathode electrode 7, the potential around the cathode electrode 7 becomes negative. , the electron beam does not move toward the anode electrode 6, and the light emitting surface 5 does not emit light.

[0005] Such a light source display tube has a back electrode 10.
are assigned to scan electrodes, and the control electrode grid electrode 8 is assigned to data electrodes, and dynamically driven. First, a voltage is applied to the back electrodes 101 arranged in a row so as to have a positive potential with respect to the cathode electrode 7, and the other back electrodes 102 10
A voltage is applied to the control grid electrodes 81 arranged in the row direction in synchronization with the voltage applied to the control grid electrodes 81 so as to have a negative potential.
Data voltage is input to 82 83 . For example, if the control grid electrode 81 is set to a positive potential, the control grid electrode 81 is set to a positive potential.
When a negative potential is applied to 2 83 , only the emission surface, that is, the pixel at the intersection of the back electrode 101 and the control grid electrode 81 emits light.

[0006]

In the light source display tube constructed as described above, each light emitting section 5R, 5G,
5B cannot be provided. In addition, in order to prevent light from leaking to adjacent light emitting parts, each light emitting part 5R, 5G,
It is necessary to secure a non-light-emitting space between 5B. For these reasons, there is a problem in that the area of each light emitting section is limited. In order to increase the brightness of the light-emitting surface under the condition that the area of the light-emitting part is constant, it is necessary to increase the irradiation density of the electron beam, but this reduces the luminous efficiency of the phosphor and increases the fluorescence This causes the problem of shortening the lifespan of the body and, ultimately, the lifespan of the display tube for the light source.

[0007]

[Means for Solving the Problems] The light source display tube according to the present invention has a front panel with an uneven inner surface, thereby increasing the brightness of the light emitting surface without increasing the irradiation density of the electron beam. Measure.

[0008]

[Effect] The surface area of the light emitting part is increased compared to the conventional one, so
The density of the electron beam irradiated per unit area of the light emitting surface remains the same as before, and the brightness of the light emitting surface is improved. In addition, when obtaining the same brightness of the light emitting surface as in the past, the irradiation density of the electron beam can be lowered, suppressing a decrease in luminous efficiency and extending the life of the light source display tube.

[0009]

[Example] Example 1. Hereinafter, the present invention will be explained based on embodiments shown in the drawings. Here, a case will be described in which the light emitting surfaces are arranged in a 3×3 matrix. 1 and 2 are a sectional view and a front view of a light source display tube according to a first embodiment of the present invention. In FIG. 1, the same numbers as in FIG. 5 indicate the same parts, and the difference from FIG. The main point is that the substantial surface area of the light emitting surface 5 is increased without changing the area of the light emitting surface 5 when the tube is viewed from the front. Therefore, FIG. 2 looks similar to when the conventional example is viewed from the front.

[0010] The front panel 2 is manufactured by injecting high temperature molten glass into a mold made of a carbon-based material having a desired shape, and then cooling the glass. Alternatively, it can be manufactured by pressing a mold made of a carbon-based material into a desired shape against a plate glass under a constant pressure, and then heating the mold in a high-temperature furnace. The light emitting surface 5 is formed by applying phosphor to a predetermined position on the inner surface of the front panel 2 manufactured in this manner so as to have an appropriate thickness.

In the light source display tube constructed in this manner, when the light emitting surface 5 is irradiated with the electron beam 13, it emits light in each color of R, G, and B. is controlled by dynamic drive. In the light source display tube shown in FIGS. 1 and 2, the surface area of the light emitting surface 5 has increased, so even if the electron beam irradiation density per unit surface area of the light emitting surface 5 remains the same as in the conventional example,
The apparent brightness of the light emitting surface is improved. However, the problem that occurs in the conventional example of accelerating the decline in luminous efficiency of the phosphor by increasing the luminance of the light emitting surface does not occur. In addition, when the apparent brightness of the light emitting surface is made equal to that of the conventional example, the irradiation density of the electron beam on the light emitting surface of the light emitting surface 5 can be lowered than that of the conventional example, and a decrease in luminous efficiency can be suppressed. Can be done.

Example 2. FIG. 3 shows a second embodiment of the invention. In this embodiment, the light emitting surface 5 on the inner surface of the front panel 2 is
The portion where is formed is made concave, so that the apparent light emitting surface 5 when the light source display tube is viewed from the front is made similar to the first embodiment.
The actual surface area of the light emitting surface 5 is increased without changing the area of the light emitting surface 5. Therefore, when this embodiment is viewed from the front, it looks similar to FIG. 2.

Example 3. FIG. 4 shows a third embodiment of the invention. In this embodiment, the light emitting surface 5 on the inner surface of the front panel 2 is
unevenness is formed in the portion where the second and third
Similarly to the embodiment, the actual surface area of the light emitting surface 5 is increased without changing the apparent area of the light emitting surface 5 when the light source display tube is viewed from the front. Therefore, when this embodiment is viewed from the front, it looks similar to FIG. 2.

Three embodiments have been described above, and in all of these embodiments, an electron beam 1 is applied to the light emitting surface 5 in the same way as in the conventional embodiments.
3, it emits light in each color of R, G, and B, and the light emission is controlled by dynamic driving. Furthermore, the present invention is not limited to the above embodiments, but the gist of the present invention is to increase the actual surface area of the light emitting surface without changing the apparent area of the light emitting surface when the display tube for a light source is viewed from the front. It goes without saying that other configurations that satisfy the above requirements can also be implemented.

[0015]

[Effects of the Invention] In this invention, the area of the light emitting surface can be increased without changing the apparent area of the light emitting surface, so the irradiation density of the electron beam per unit surface area of the light emitting surface is the same as that of the conventional example. High brightness of the printing surface can be achieved by keeping the printing surface as it is. In other words, it is possible to obtain a light source display tube with high brightness while having the same lifespan as the conventional one. Further, when the luminance is the same as that of the conventional display tube, the irradiation density of the electron beam on the light emitting surface can be kept low, and a decrease in luminous efficiency can be suppressed, making it possible to obtain a light source display tube with a long life.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a light source display tube according to a first embodiment of the present invention.

FIG. 2 is a front view of the light source display tube according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a light source display tube according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a light source display tube according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing the basic structure of a conventional display tube for a light source.

FIG. 6 is a partially cutaway perspective view of a conventional display tube for a light source.

[Explanation of symbols]

1 Glass tube body 2 Front panel 3. Back panel 4 Cylindrical side plate 5. Light emitting surface 6 Acceleration anode electrode 7 Cathode electrode 8 Control grid electrode 9　Electron passing hole 10 Back electrode 11 External terminal 12 External terminal 13　Electron beam

Claims (1)

[Claims] 1. A vacuum envelope in which a front panel and a rear panel are hermetically joined to the front and rear sides of a cylindrical side plate, respectively, and a light emitting surface formed by arranging phosphors in a matrix inside the front panel. and a light source display tube comprising a control electrode for controlling light emission from these light emitting surfaces, wherein the inner surface of the front panel has an uneven shape.