JPS594438Y2 - Projection type cathode ray tube device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a projection cathode ray tube device using a Schmidt projection optical system.

Generally, in projection magnification devices that use cathode ray tubes (hereinafter abbreviated as CRT), two methods are used for optical magnification.One is to install a lens in front of the CRT image and simply magnify it using this lens. The other method uses a Schmidt mirror to magnify the image.

By the way, the former has the disadvantage that there is a lot of light loss when passing through the lens, so the latter Schmidt-Miller type, which has less light loss, is used for large screens.
Moreover, among the Schmidt mirror one-type systems, the one in which the mirror is installed inside the CRT has the great advantage that the mirror surface does not get dirty.

Therefore, in the above-mentioned Schmidt-Miller system, when reproducing a color image, red, blue, and green phosphors are coated on the phosphor surface, and three
CRT images of books are composited on an enlarged screen.

The problem here is that the three enlarged images must be correctly aligned on the screen surface, and currently alignment is difficult and the images are significantly misaligned.

Furthermore, three CRTs must be used, making the device itself complex and consuming a lot of power.

In addition, the index signal generation method of the conventional beam index type CRT, which reproduces color images on the screen using a single CRT, uses phosphor stripes that emit light close to ultraviolet light in addition to the three primary color phosphors. A phosphor is formed by coating the pitch of the three primary color phosphors at a fixed ratio, and the weak light emitted by an electron beam is applied to the ultraviolet phosphor, which emits light close to ultraviolet. It is detected by a photodetector such as a player, and this detection signal is used as an index signal to detect a position signal of the electron beam on the phosphor.

However, this method requires an expensive photodetector such as a photomultiplier, and furthermore, it is difficult to process the index signal because it is not possible to obtain light of uniform intensity from the entire surface of the phosphor. It is.

This invention takes the above points into consideration, takes advantage of the advantages of the Schmidt-Miller one-sided system, and uses a beam index system using comb-shaped electrodes to reproduce color images on the screen using a single CRT. Next, this invention will be explained in detail with reference to drawings showing one embodiment thereof.

As shown in FIG. 1, an electron gun 3 that emits an electron beam 2 whose intensity is modulated by a video signal is provided at the rear of a vacuum vessel 1. A metal cooling plate 5 is provided which faces the electron gun 3 and has an exposed inner surface facing the inside of the vacuum chamber 1 and has a smaller area than the face plate 4. As shown in FIG. An insulating layer is provided by applying a material 6 to form a pair of comb-shaped electrodes 7 and 7', and a phosphor 8 on which the electron beam 2 is projected onto the inner surface of the metal cooling plate 5 is formed into a comb-shaped electrode. A concave mirror 9 is provided at the rear inner side of the vacuum vessel 1, with the concave mirror 9 interposed between the electron beams 2 and the phosphor 8, and which reflects the image light generated by the projection of the electron beam 2 onto the phosphor 8 and radiates it forward through the face plate 4. Furthermore, in order to detect the electron beam current passing through the phosphor 8 and flowing into the comb-shaped electrodes 7, 7' as an index signal isolated from the high-voltage power supply 10 for driving the CTR, the primary side is connected to the metal cooling plate 5. An index detecting transformer 12 whose next side is connected to the index terminal 11 is provided, and an index signal is obtained by creating a state close to resonance with the capacitance between the comb-shaped electrodes 7 and 7'.

Note that the means for installing the metal cooling plate 5 on the face plate 4 is to form a hole in the center of the face plate 4, penetrate the metal cooling plate 5 into this hole, close the gap, and weld powder glass or the like. Then, form the frit seal 13.

Further, as shown in FIG. 3, the phosphor 8 is a red phosphor 8R.
1 green phosphor 8G0 and blue phosphor 8B alternately arranged on metal cooling plate 5
They are arranged on the inner surface of the screen to form triplet stripes of three primary colors.

Furthermore, 14 is a deflection coil for deflecting the electron beam 2, and 15 is a metal fitting that supports the concave mirror 9.

Therefore, in the embodiment described above, the electron beam 2 emitted from the electron gun 3 is projected onto the phosphor 8, and red and green colors are generated by the projection of the electron beam 2.

The blue image light 16 is reflected by the concave mirror 9, and the enlarged image light 16' is emitted onto the enlarged screen in the same direction as the emission direction of the electron gun 3, while passing through the phosphor 8 and the comb-shaped electrode 7. An index signal is generated at the index terminal 11 via the transformer 12 by the electron beam current that alternately flows into the
The index signal causes the phosphor 8 of the electron beam 2 to
The upper scanning position is detected and the color image is sequentially enlarged and displayed on the screen.

In the embodiment described above, the heat of the metal cooling plate 5 increased by the electron beam 2 projected onto the phosphor 8 at high speed is dissipated to the outside space, so deterioration of the phosphor 8 can be prevented. .

As described above, according to the radiation type cathode ray tube device of this invention, an electron gun that emits an electron beam is provided at the rear of the vacuum container, a metal cooling plate is provided in the center of the face plate of the vacuum container, and the metal cooling plate is provided at the center of the face plate of the vacuum container. 1 by insulating material on the inner surface of the vacuum container.
In addition to forming a pair of comb-shaped electrodes, a phosphor on which an electron beam is projected onto a metal cooling plate is provided with the comb-shaped electrode interposed, and the image light generated by the projection of the electron beam onto the phosphor is reflected. By providing a concave mirror that emits light forward through the vacuum container on the rear inside of the vacuum container, the efficiency of image light utilization is high and the mirror can be prevented from becoming dirty.

In particular, by adopting a beam inch system with high luminous efficiency without using a shadow mask, color projection is possible with a single tube, which eliminates the need to align the multi-tube composite image on the projection screen surface. It is possible to improve the brightness, which is the most problematic aspect of this type of projection tube, with the same power consumption.Furthermore, it adopts a structure in which the comb-shaped electrode is formed on an insulating film provided on a metal cooling plate, which should serve as the target surface. Therefore, not only can it be mass-produced efficiently in accordance with the fluorescent stripe type process, but also the inter-electrode capacitance of the comb-shaped electrode can be made to resonate with the primary coil of the detection transformer. This method is compared to a method in which an index signal is obtained by detecting ultraviolet light using a flash drive, and it is also compared to a simple diversion of the technique of simply inserting a thin indicator wire between fluorescent surfaces to form a comb-shaped electrode. However, not only can the device be significantly simplified and lowered in cost, but also reliability can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of one embodiment of the projection type cathode ray tube device of this invention, Fig. 2 is a structural diagram of the comb-shaped electrode of Fig.
It is a partially enlarged view of the figure. 1... Vacuum container, 2... Electron beam,
3...Electron gun, 4...Face plate, 5...Metal cooling plate, 6...Insulator, 7.7'... - Comb-shaped electrode, 8... fluorescent substance, 9... concave mirror, 11... index terminal.

Claims (1)

[Scope of utility model registration request] In a projection cathode ray tube device that has a Schmidt mirror on the inner surface of the funnel part and a convex target surface in the center of the face plate, a metal tube is used that exposes the heat dissipation part to the outside and exposes the convex surface on which the target surface is to be formed inside the tube. Three primary color fluorescent stripes aligned in parallel in a vertical scanning direction are formed on a pair of comb-shaped electrodes formed on an insulating film provided on the convex surface of the cooling plate, and when an electron beam scans the fluorescent stripes, A projection type cathode ray tube device configured to derive an index signal generated between the comb-shaped electrodes via a detection transformer including a primary coil that resonates at the index signal frequency in combination with the interelectrode capacitance of the comb-shaped electrodes.