JPH0693350B2 - Beam index type cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Use The present invention relates to a beam index type cathode ray tube formed by horizontally extending a phosphor line and an index line for image display on a display surface, and more particularly, The present invention relates to an electron beam spot tracking servo which uses at least two kinds of index lines having different emission wavelengths.

B. Outline of the Invention The present invention is a beam for extending tracking lines of an electron beam spot by horizontally extending a fluorescent substance line for image display and at least two kinds of index lines having different emission wavelengths on a display surface. In the index type cathode ray tube, by stacking a plurality of light collectors in which materials for wavelength conversion by absorbing light having a wavelength corresponding to the wavelength of the index light are dispersed, and detecting the index light,
The wavelength separation can be performed without optical parallax, good tracking servo can be performed, and high light collection efficiency can be obtained.

C. Conventional Technology Conventionally, fluorescent lines for image display and index lines are arranged on the display surface, index light emitted from the index lines is detected, and based on this detection output (index signal) A beam index type cathode ray tube that controls an electron beam is known.

As this beam index type cathode ray tube, a structure as shown in FIG. 3, for example, has been proposed. In FIG. 3, on the display surface 101, red, green, color phosphor lines 102,102,102 blue, ... is, are respectively extended in the horizontal direction is the main scanning direction of the electron beam E _B by the electron gun 103 There is. These color phosphor lines 102, 102, 102, ... Are arranged cyclically in the vertical direction, and guard bands 104, 104, ... Are formed between the color phosphor lines 102, 102, 102 ,. On the guard bands 104, 104, ..., Index lines 106A, 106B, ... Having different emission wavelengths are alternately formed via a metal back 105. Also, a metal back 107 is applied to the inner peripheral surface of the pipe wall,
A portion where the metal back 107 is not applied serves as a light receiving window 108. The light receiving window 108 includes optical filters 111A and 11A.
A photodetector device 110 composed of 1B and photoelectric conversion elements 112A and 112B is arranged to face each other. The photo-detecting device 110 separates the index lights L _A and L _B having different wavelengths emitted from the index lines 106A and 106B by being irradiated with the electron beam E _B from the electron gun 103 by the optical filters 111A and 111B. Then, the photoelectric conversion elements 112A and 112B convert the electric signals to perform detection, and a tracking error signal is generated based on the detection output, and tracking servo, that is, position control in the vertical direction of the electron beam spot is performed. .

D. Problems to be Solved by the Invention By the way, in the above-mentioned beam index type cathode ray tube in which the index lights L _A and L _B are separated by using the optical filters 111A and 111B, the optical filters 111A and 111B are connected to the light receiving window 108. Must be arranged in parallel with respect to each other, and the intensity ratio of light incident on the photoelectric conversion elements 112A, 112 is displayed by the optical parallax of the paths of the two index lights L _A , L _B , that is, the optical paths. There is a problem that it changes due to a change in the position of the bright spot on the surface 101, and an error is mixed in the tracking error signal for performing the tracking servo. Further, if the area of the photodetector 110 is increased in order to improve the efficiency of collecting the index lights L _A and L _B , the optical parallax becomes larger and the error of the tracking error signal increases.

Therefore, the present invention has been proposed in view of the above-mentioned conventional problems, and it is possible to perform an excellent tracking servo by preventing an error from being mixed in a tracking error signal, and to obtain a high focusing efficiency. A beam index type cathode ray tube is provided.

E. Means for Solving the Problems In order to achieve the above-mentioned object, the beam index type cathode ray tube according to the present invention includes at least two kinds of index lines formed on the display surface and having different emission wavelengths. A beam index type cathode ray tube having a photodetector arranged to face the light receiving window and detecting index light emitted from the index line in response to irradiation of an electron beam, wherein the photodetector is the number of types of the index line. Is formed by stacking a number of light-collecting plates corresponding to, and photoelectric conversion elements are arranged on the respective end surfaces of these light-collecting plates. Each light-collecting plate is provided with the index light of each index light emitted from the corresponding index line. Characterized by the dispersion of materials that absorb wavelengths corresponding to wavelengths and perform wavelength conversion That.

F. Action According to the present invention, at least two light collectors in which materials for absorbing wavelengths corresponding to the wavelength of the index light and performing wavelength conversion are dispersed are laminated, and the optical parallax is reduced. Wavelength separation can be performed without this.

G. Example Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

A beam index type cathode ray tube of one embodiment is shown in FIG. On the display surface 1, red, green, and blue color phosphor lines are provided.
2,2,2, ..., it is extended respectively in the horizontal direction is the main scanning direction of the electron beam E _B by the electron gun 3. These color phosphor lines 2, 2, 2, ... Are arranged cyclically in the vertical direction, and the color phosphor lines 2, 2, 2 ,.
Are extended respectively in the horizontal direction is the main scanning direction of the electron beam E _B by. These color phosphor lines 2,2,
2, ... Are arranged cyclically in the vertical direction, and non-luminous guard bands 4, 4, ... Made of carbon, for example, are formed between the color phosphor lines 2, 2, 2 ,. ing. Two kinds of index lines 6A, 6B, ... Having different emission wavelengths are alternately formed on the guard bands 4, 4, ... Via a metal back 5 made of, for example, Al. For example, YAG: Ce is used as the fluorescent substance that constitutes the index line 6A, and the emission wavelength, that is, the wavelength of the index light L _A is
It is about 510 nm. Further, as the fluorescent substance forming the index line 6B, for example, so-called P47 is used, and the emission wavelength, that is, the wavelength of the index light L _B is 410 nm.
It will be about.

A metal back 7 made of, for example, Al is provided on the inner peripheral surface of the tube wall, and a portion where the metal back 7 is not provided is a light receiving window 8. In the light receiving window 8, two laminated light collectors 11A, 11B having a large refractive index and the light collectors 11A, 1B are stacked.
Photoelectric conversion elements 12A, 12B respectively arranged on each end face of 1B
The photo-detecting device 10 having the is disposed oppositely. Second
As shown in the enlarged view of the figure, a layer having a refractive index smaller than that of the light collectors 11A and 11B, an air layer AI in this embodiment, is provided between the light collectors 11A and 11B. Light board 11A
And the photoelectric conversion element 12A, and between the light collector 11B and the photoelectric conversion element.
A layer having a high refractive index, grease layers 13A and 13B in the present embodiment, are provided between 12B. Light collector 1 above
1A has a wavelength of 510n, which corresponds to the wavelength of the index line 6A.
A fluorescent dye (for example, so-called acid red (Ac red) as a material that absorbs light of about m and emits light of about 610 nm, that is, performs wavelength conversion and transmits light of about 410 nm.
id Red)) is distributed. Further, the light collecting plate 11B is a fluorescent dye as a material that absorbs light having a wavelength of about 410 nm corresponding to the wavelength of the index light L _{B from} the index line 6B and converts the light into light having a wavelength of about 510 nm (for example,
So-called 510GB), and absorbs light with a wavelength of about 510nm
A fluorescent dye (for example, so-called 61R) as a material that converts the wavelength of light to about 610 nm is dispersed. The above-mentioned fluorescent dye Acid Red has an absorption band shifted to the longer wavelength side than that of the above-mentioned fluorescent dye 61R, and almost all light with a wavelength of about 410 nm can pass through. The light collectors 11A and 11B are
For example, it is formed by injection molding by mixing each fluorescent dye in a transparent acrylic resin. Further, for the photoelectric conversion elements 12A and 12B, for example, silicon PIN diodes are used.

In thus constructed beam index type CRT, electronic index line 6A in accordance with the irradiation of the electron beam E _B from the gun 3, the index light L emitted from 6B
_A and L _B are illuminated through the light receiving window 8. The index light L _A having a wavelength of about 510 nm is absorbed by the light collector 11A and converted into light having a wavelength of about 610 nm. This wavelength-converted light is the light collecting plate.
It reaches the end of 11A and enters the light receiving part of the photoelectric conversion element 12A. On the other hand, the index light L _B having a wavelength of about 410 nm is absorbed by the light collector 11B. The index light L _B absorbed by the light condensing plate 11B is converted into light having a wavelength of about 510 nm, and the wavelength 6
It is converted to light of about 10 nm. Then, the wavelength-converted light reaches the end portion of the light collector 11B and enters the light receiving portion of the photoelectric conversion element 12B. Here, the light converted to the wavelength of about 510 nm by the light condensing plate 11B is immediately converted to the light of the wavelength of about 610 nm (the mean free path is short).
The component of light of about 10 nm is very small, and the two index lights L _A and L _B are completely wavelength separated. Further, since the two light collectors 11A and 11B are laminated and the optical paths of the index lights L _A and L _B entering the light receiving window 8 are almost the same, no optical parallax occurs. Therefore, the intensity ratio of the light incident on the photoelectric conversion elements 12A, 12B does not change due to the change of the bright spot position on the display surface 1, and the photoelectric conversion elements 12A, 12B
No error is mixed into the tracking error signal generated based on the detection output from B. Therefore, good tracking servo can be performed.

Further, the light whose wavelength has been converted by the light collectors 11A and 11B is
Since A and 11B have a large refractive index, they are confined and reach each end, and enter the light receiving portions of the photoelectric conversion elements 12A and 12B, respectively. Therefore, the condensing efficiency of the index lights L _A and L _B is high, and the photoelectric conversion efficiency as a whole is also high. Furthermore, since there is no optical parallax, the light collectors 11A and 11B
It is also possible to further increase the light collection efficiency by increasing the area.

H. Effect of the invention As is clear from the description of the above-mentioned embodiments, according to the beam index type cathode ray tube of the present invention, the materials that perform wavelength conversion by absorbing the light of the wavelength corresponding to the wavelength of the index light, respectively. Since a plurality of dispersed light collectors are stacked, wavelength separation can be performed without optical parallax. Therefore, no error is mixed in the tracking error signal, and good tracking servo can be performed. Further, since there is no optical parallax, it is possible to increase the area of the light collecting plate and obtain higher light collecting efficiency.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a beam index type cathode ray tube according to the present invention, and FIG. 2 is an enlarged sectional view of an essential part of FIG. FIG. 3 is a side sectional view showing a conventional example of a beam index type cathode ray tube. 1 ... Display surface 6A, 6B ... Index line 8 ... Light receiving window 10 ... Photodetector 11A, 11B ... Light condensing plate 12A, 12B ... Photoelectric conversion element

Claims (1)

[Claims] 1. At least two types of index lines having different emission wavelengths formed on a display surface, and index light emitted from the index lines which are arranged opposite to a light receiving window in response to electron beam irradiation. In a beam index type cathode ray tube having a photodetector, the above-mentioned photodetector is constructed by stacking a number of light collectors corresponding to the number of types of index lines, and photoelectric conversion elements are arranged on respective end faces of these light collectors. It is characterized in that each of the light collectors is dispersed with a material that performs wavelength conversion by absorbing light having a wavelength corresponding to the wavelength of each index light emitted from each corresponding index line. Beam index type cathode ray tube.