JPS5929943B2 - cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube suitable for a large-screen image display device constructed outdoors, for example.

In recent years, we have begun to see cases where large image display devices are installed on bank screens at baseball stadiums, walls of buildings, etc., and moving images are projected.

This image display device requires a high-brightness light source as an element that becomes a pixel so that it can be seen from a long distance, and usually high-power, high-brightness incandescent light bulbs are often used, and several seven (and tens of thousands of light bulbs are used on a flat surface). It is configured to display an image by placing it on the screen and blinking with a relay inch or the like.

However, such an image display device has the following drawbacks.

That is, in order to blink a high-power light bulb, it is necessary to turn it on and off with a switch, and to display a moving image, the light bulb must be repeatedly turned on and off at high speed, which requires a considerable amount of power.

Moreover, there is a limit to high-speed switching due to the time delay in the temperature rise of the bulb filament, and it is even more difficult to perform brightness modulation, making it difficult to display television broadcasts on such large image displays. This was not possible with the equipment.

Therefore, it is even more difficult to construct a multicolor image such as that used in commercial color television broadcasting because it is necessary to appropriately modulate the brightness of the incandescent light bulbs of the three primary colors of red, green, and blue, and perform color synthesis.

Furthermore, incandescent light bulbs have a short lifespan, and maintenance such as replacement requires a great deal of effort and expense.

Furthermore, when incandescent light bulbs are arranged on a flat surface, the ratio of the light-emitting portion to the area, that is, the light-emitting area efficiency, is low, making it difficult to obtain a bright image, and also resulting in a rough-textured image.

This invention was made to eliminate such drawbacks, and instead of incandescent light bulbs, it enables high-speed brightness modulation with low power.
The present invention provides an anode ray tube with a long life and reduced maintenance costs.

Hereinafter, this invention will be explained in detail using an embodiment of the invention shown in FIG.

In FIG. 1, a tube body 1 is composed of an upper surface body 2 and an upper surface body 3, which are joined by a flint seal 4. As shown in FIG.

The upper body 2 is made of glass since it has a window 5 through which light emitted from the fluorescent surface passes, but the upper body 3 may be made of glass, ceramic, or metal.

The upper body 2 and the area outside the window 5 may be made of ceramic or metal.

The window 5 is configured as a semi-convex lens with a convex outer side and a planar inner side.

The focal length of this semi-convex lens may be approximately the distance to the viewer's position of the giant image display device equipped with this cathode ray tube.

The cathode 6 and the control electrode 1 are visible through the window in the top body 2.

The cathode 6 is placed approximately in the center of the window 5.

A plurality of terminals 8 are installed around the upper body 2 for applying an operating voltage to a cathode 6, a control electrode 1, an accelerating electrode, etc. to be described later.

An anode button 9 for applying a high voltage to the fluorescent surface is embedded in the periphery of the upper body 3.

The detailed structure of the above structure can be understood from FIG. 2, which shows a schematic partial cross-sectional structure.

Referring to FIG. 2, the bottom surface 10 of the top body 3 is substantially planar, and a phosphor layer 11 is formed on the bottom surface 10 by a conventional method, and a phosphor layer 11 is formed on the back surface by a conventional method. A fluorescent surface 13 consisting of a metal bank 12 is formed.

The metal bank 12 is connected to the anode button 9 and functions both as an electrode for applying a voltage between the phosphors and as a film for reflecting light emitted from the phosphor layer 11.

An accelerating electrode 14 is disposed on the upper body 2, extending substantially parallel to the fluorescent surface 13, and a control electrode 7 is disposed parallel to the accelerating electrode 14 at a predetermined interval.

The acceleration electrode 14 and the control electrode 1 are made of mensch-like planar electrodes, and are each held by a support frame 15.

Note that the accelerating electrode 14 may be composed of a plurality of electrodes (0) A cathode 6 is arranged in parallel at a predetermined interval at approximately the center of the back of the control electrode 1.

The cathode 6 consists of a heater 16 and an electron emissive material 11 coated around the periphery.

In the above configuration, the control electrode γ is connected to the cathode 6.
A negative voltage is applied to the accelerating electrode 14, a positive voltage is applied to the accelerating electrode 14, and a high voltage higher than the accelerating electrode voltage is applied to the fluorescent surface.

These voltages are adjusted so that the electron flow 18 (indicated by dotted lines in the figure) emitted from the cathode 6 forms a Fland beam that irradiates the entire fluorescent surface 13, as shown in FIG.

Light emission 19 (indicated by arrows in the figure) from the entire surface of the fluorescent surface 13 passes through the mesh of the accelerating electrode 14 and the control electrode 1, and is emitted to the outside of the tube body 1 through the window 5 of the upper body 2.

As mentioned above, the fluorescent surface 13 has a substantially planar structure and
Therefore, the emitted light 19 from now on is emitted as a substantially parallel element 1, so it enters the convex lens of the window 5 as parallel light, and when passing through the window 5, it is refracted by the convex lens and focused. The light will be focused at a distance.

An image display device is constructed by arranging such cathode ray tubes in a plane.

Images are projected by sequentially modulating the brightness of individual cathode ray tubes as pixel components.

The cathode ray tube constructed in this manner has the following features.

In other words, unlike incandescent light bulbs, the brightness can be modulated by changing the potential of the control electrode γ in the same way as with conventional cathode ray tubes, so pixels can be switched quickly using small amounts of power using electronic circuits, which is useful for television broadcasting. It is possible to project.

Since the emitted light 19 from the fluorescent surface 13 is refracted and focused at the viewer's position by the convex lens, the emitted light 19 does not dissipate and can function as a bright light source.

The cathode 6 is strip-shaped and has a large electron emitting area, and since controlled acceleration is performed using a mensch electrode, a large current can be extracted, resulting in a bright light source.

Since the fluorescent surface 1γ can be formed into any shape, it becomes a bright light source with high luminous area efficiency when installed in an image display device.

This high light emitting area efficiency makes it possible to obtain finer-grained and easier-to-see images than in conventional image display devices using incandescent light bulbs.

Since the bottom surface 10 of the top body 3 can be made smooth, the metal back 1
2 can be made mirror-like to improve the reflection performance, and the emitted light L19 of the phosphor layer 11 can be efficiently reflected to obtain a bright cathode ray tube.

Since the phosphor layer 11 is directly irradiated with electrons by the Fland beam, there is no energy loss of the electron beam due to the metal bank, unlike the threshold loss due to the metal bank of a normal cathode ray tube, and the voltage between the phosphors can be adjusted to the threshold value. can be lowered only.

Since the fluorescent surface 13 is disposed at the back of the cathode ray tube, it can be easily cooled and is suitable for a large screen image display device constructed outdoors.

Since brightness can be modulated, by regularly arranging three color cathode ray tubes coated with red, green and blue phosphors, and making a set of three colors into one pixel, each color can be modulated and color synthesized. It is possible to project color images.

As described above, the cathode ray tube according to the present invention can efficiently use the light emitted from the fluorescent surface. It has many advantages such as, and if an image display device is constructed using it, it is an excellent device that has functions such as being able to display television broadcasts.

It goes without saying that the shapes of the tube body, electrode mensch, etc. are not limited to those shown in the drawings.

[Brief explanation of the drawing]

Fig. 1 is an external view showing a schematic structure for explaining the overall configuration of an embodiment of the present invention, and Fig. 2 is a schematic cross-sectional view of the structure for explaining the internal structure of the polar ray tube shown in Fig. 1. The partial view, FIG. 3, is a schematic structural sectional view for explaining the operating function of the @ polar ray tube shown in FIG. In the figure, 1 is a tube body, 5 is a window consisting of a convex lens, 6 is a cathode, γ is a control electrode, 13 is a fluorescent surface, 14 is an accelerating electrode,
19 is light emission from the fluorescent surface. In addition, in the figures, the same or corresponding parts are indicated by the same reference numerals.

Claims (1)

[Claims] 1 a cathode, a control electrode configured with a mesh arranged in front of this cathode, an accelerating electrode configured with a mesh arranged in the front opposite to the cathode of this control electrode, and arranged opposite to this accelerating electrode. The tube includes a fluorescent surface and a tube body housing the same, the light emitted from the fluorescent surface passes through the mensch and is emitted outside the tube body, and a convex lens is provided in a portion of the tube body through which the light emission passes. A cathode ray tube characterized by: