JPH023247Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a picture tube in a beam index type color television.

In general, beam index type color picture tubes are
As shown in FIGS. 2 and 3, three primary color phosphor strips 21 and 2 of red, green and blue are provided on the inner surface of the face plate 16.
2 and 23 are repeatedly applied to form a fluorescent surface 2, and on the fluorescent surface 2, a set of three primary color phosphor strips (1
Index phosphor strips 3 are provided at pitches which have a fixed relationship with the pitches of the triplets (referred to as triplets). When this phosphor surface 2 is scanned with a single electron beam 15, the index phosphor strip 3 is excited and emits an optical signal 31. By detecting the signal 31 with the photodetector 4 provided in the funnel section 17 of the picture tube, the accurate scanning position of the single electron beam 15 is determined, and furthermore, the three primary color signals are switched using this signal and supplied to the electron gun. By controlling the electron beam,
An appropriate color image is being played.

The index phosphor strip 3 has an electron beam 1
It is a necessary condition for normal color reproduction to generate an index signal with a fast response speed that closely matches the scanning position during scanning. Therefore, the decay time of the index optical signal 31 is usually
20 nsec or less, and since the signal 31 is detected through the glass wall of the funnel section 17, the emission wavelength is limited to visible light, infrared light, or ultraviolet light close to the visible range, which is less attenuated by the glass wall. be done.

Conventionally, P47, for example, is generally known as a fluorescent substance that satisfies the above conditions, but since all of these have emission centers in the ultraviolet region, the photodetector 4 that can be used is a photomultiplier tube. Alternatively, it is limited to electron tube type devices such as phototubes that have a sensitivity range that extends to the ultraviolet region, and solid-state devices that have a sensitivity range of visible light or infrared light cannot be used. Electron tubes are more expensive to manufacture than solid-state devices, and require high voltage and are difficult to handle, so it has been desired to use solid-state devices that are inexpensive and easy to handle.

The present invention provides a photodetector by providing an index phosphor strip in the picture tube and a phosphor for light conversion that emits visible light when excited by ultraviolet light emitted from the phosphor strip. Not limited to conventional electron tubes,
The object of the present invention is to provide a beam index type color picture tube that can utilize inexpensive solid-state elements that operate in the visible range.

The present invention will be specifically described below based on embodiments shown in the drawings.

The beam index type color picture tube 1 according to the present invention, as shown in FIG.
is emitted, and this beam 15 is swung by a deflection coil 12 to scan a fluorescent surface 2 formed on the inner surface of a face plate 16.

As shown in FIG. 2, the phosphor surface 2 is formed by repeatedly applying phosphor strips 21, 22, 23 in the three primary colors of red, green, and blue, and between the phosphor strips, a non-luminescent material made of graphite or the like is formed. It is formed with a substance 24 interposed therebetween.

An aluminum metal bag 25 is uniformly deposited on the phosphor surface 2, and three primary color phosphor strips 2 are further applied thereon.
The index phosphor strip 3 is coated over the entire scanning surface in a fixed relationship with the index phosphor strips 1, 22, and 23, for example, at the same pitch as one triplet of the three primary color phosphor strips.

The index phosphor strip 3 is a phosphor that emits ultraviolet light with a decay time of 20 nsec or less when excited by the electron beam 15 during scanning with the electron beam 15, for example, P
47 is used.

The inner surface of the funnel portion 17 receives the index optical signal 6.
All but one extraction window 51 is uniformly covered with a metal film 5. The metal film 5 is formed by aluminum vapor deposition or the like, and is electrically connected to the aluminum metal bag 25 to maintain the inner surface of the funnel portion at an equal potential, thereby preventing disturbance of the electron beam during image reproduction. Perform proper color reproduction.

The inner surface of the funnel portion 17 is covered with the metal film 5 as described above.
After covering with phosphor 6, a phosphor 6 for index signal conversion is further uniformly applied. The conversion phosphor 6 emits ultraviolet light 31 emitted from the index phosphor strip 3.
Accordingly, CeTbMgAl ₁₁ O ₁₉ :Ce, which emits visible light or infrared light with a decay time of 20 nsec or less, and which emits green light, is used in this embodiment.

When the fluorescent surface 2 is scanned by the single electron beam 15, ultraviolet light 31 is emitted from the index phosphor strip 3 corresponding to the scanning position of the beam 15. The ultraviolet light 31 excites a phosphor for index signal conversion provided in the funnel section 17 to generate visible light 6.
Generate 1. The visible light 61 is reflected by the metal film 5 and is effectively extracted to the outside of the picture tube through a window 51 provided in the metal film 5.

The optical signal 61 emitted to the outside as described above is detected by a photodetector 4 disposed close to the outer surface of the funnel section 17 corresponding to the window section 51, for example, a solid state such as a phototransistor having a sensitivity range in the visible light region. The signal is detected by an element and converted into an electric signal, and a frequency selector 71 extracts only a signal corresponding to the pitch of the index phosphor strip 3, which is further amplified by an amplifier 72.

After that, the signal is sent to the signal processing circuit 73,
In substantially the same manner as in the conventional method, the index signal is converted into an index signal having a frequency corresponding to the pitch of the three primary color phosphor stripes and synchronized with the scanning position of the single electron beam 15, and used for color reproduction.

Furthermore, since the index phosphor strip 3 does not need to take out the emitted light to the outside, the material thereof is not limited to those that emit ultraviolet light close to visible light, and materials that emit light in the vacuum ultraviolet region can also be used.

As described above, the present invention includes the index phosphor strip 3 that emits ultraviolet light 31 and the phosphor 6 for index signal conversion that emits visible light or infrared light 61 upon excitation of the ultraviolet light 31. The types of photodetectors 4 that can be used to detect index signals are not limited to those that have a wide sensitivity band from the ultraviolet region to visible light, as in the past, but instead are inexpensive ones that react with visible or infrared light. It has the excellent effect of being able to use solid-state devices that are easy to handle.

[Brief explanation of the drawing]

FIG. 1 is a schematic view of a beam index type receiver using a picture tube according to the present invention, FIG. 2 is an enlarged sectional view of a fluorescent surface, and FIG. 3 is a sectional view of a conventional example. 21, 22, 23... Three primary color phosphor stripes, 3...
Index phosphor strip, 6... phosphor for index signal conversion.

Claims (1)

[Scope of claim for utility model registration] On a fluorescent surface repeatedly coated with three primary color phosphor strips,
In a beam index type color picture tube provided with an index phosphor strip 3 that emits ultraviolet light by excitation of an electron beam in a constant relationship with the pitch of the three primary color phosphor strips, it is formed on the inner surface of the funnel part, an index signal converting phosphor 6 that generates visible light or infrared light when excited by the ultraviolet light and outputs it again to the inside of the picture tube; A beam index type color picture tube comprising: a window portion 51 leading out of the tube; and a photodetector 4 disposed outside the picture tube corresponding to the window portion 51.