JPS6326920Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a beam index type color picture tube device. As shown in Fig. 1, the beam index type color picture tube has three primary color phosphors R, G, and B repeatedly arranged in a stripe pattern on the inner surface of the face plate 1 with a black guard band 2 in between, and an aluminum film on the inner surface. When an electron beam 6 emitted by a single electron gun 5 is swept over a surface on which index phosphors 4 are repeatedly arranged in a striped manner through a melbac 3 made of A light transmission window 8 in which an optical signal 7 is formed on the back of the picture tube
It is designed to lead to the photodetector 9 via the
The index signal caught by the detector 9 and converted into an electrical signal is used to cause the beam to impact a predetermined phosphor.

However, in this picture tube, the optical signal generated from the index phosphor 4 is dispersed in all directions, and the light-receiving surface of the photodetector 9 is limited, so that the efficiency of converting the optical signal into an electrical signal is extremely poor. Therefore, it is necessary to use a photodetector such as a photomultiplier tube or a phototube, which has high sensitivity and a relatively wide light-receiving surface, but such a photomultiplier tube or phototube has the disadvantage of being expensive.

Therefore, the purpose of the present invention is to provide a detector with a structure that allows good light focusing, so that solid-state photodetecting elements such as photodiodes and phototransistors, which can be mass-produced at low cost, can be used. . The present invention will be described in detail below with reference to the drawings.

Generally, a lens is used to efficiently collect light onto a small light-receiving surface. However, when a lens is used, there may be an angular restriction on the light reaching the light receiving surface of the photodetecting element, as shown in FIG. 3a. That is, since there is a space, that is, air (optical refractive index n approximately 1.0) between the lens 10 and the photodetector element 11, an optical interface having a critical angle for total reflection is formed, and the effective incident angle of the index optical signal is 38 degrees. Within. Incidentally, the refractive index n of the lens is approximately 1.6. while 20
Since the effective angle of incidence required for a picture tube with a 90-inch deflection is approximately 70 degrees, a detector with a condensing structure in which the effective angle of incidence of the index optical signal is no more than 38 degrees cannot be put to practical use. FIG. 3b shows a case where epoxy resin 12 is filled between lens 10 and photodetector element 11, and since the refractive index n of the epoxy resin is about 1.58, the effective angle of incidence is expanded to 80°. The filling is transparent to the index optical signal and has a refractive index that is 0.9 times or more the refractive index of the lens 10.

Next, when the index light signal is focused on the light-receiving surface of the photodetector element using a lens, the index phosphor 4, which is the light source of the index light, is provided on the entire inner surface of the face plate in accordance with the above-mentioned rules, and the second As shown in the figure, since the metal back 3 extends to the back of the picture tube, the actual light source becomes extremely large compared to the lens aperture, and not only cannot the light be focused on the light receiving surface of the photodetector 11, but also the index optical signal cannot be collected. The light collection rate changes depending on the light emitting location, and the S/N ratio of the index electric signal increases depending on the location, which is inconvenient.

However, in the present invention, as shown in FIG. 4, a lens 10, a solid-state photodetector element 11 such as a photodiode facing the lens 10, and a transparent material provided between them and having a refractive index of 0.9 times or more that of the lens A light detection device comprising: a material 12'; and a reflective layer 13 applied around the transparent material and having a tapered shape from the lens side toward the light detection element so as to effectively guide optical signals to the light detection element. Since the device 14 is attached to the light transmission window 8 on the back side of the picture tube, a highly efficient light detection structure that is not affected by the spatial position of the light emitting source can be realized. Incidentally, the format of the detection structure for such an index optical signal is such that a photodetecting element 11 is formed in advance on a ceramic substrate 15 and a reflective layer 13 such as an aluminum film is applied to the conical inner surface of a frame 16 having a conical inner surface. After that, fix it on the picture tube,
Subsequently, the gap between the lens 10 and the photodetecting element 11 is filled with a transparent material 12' such as epoxy resin. Note that the transparent material 12' is not limited to epoxy resin, but may be any other resin as long as it has the above-mentioned properties. Further, the reflective surface of the reflective layer 13 is not limited to a conical shape as long as it functions to guide the index light to the photodetecting element. Incidentally, in FIG. 4, it is preferable to insert an optical filter at an appropriate location to prevent unnecessary light from reaching the photodetecting element 11.

As explained above, according to the present invention, it is possible to realize light detection that covers all positions of the index light emission source, and the detector structure has a high efficiency of condensing the index light. The present invention is extremely effective because it allows the use of inexpensive elements such as photodiodes and phototransistors with small values.

[Brief explanation of drawings]

FIG. 1 is a drawing showing the inner surface of the face plate of a beam index type color picture tube.
FIG. 2 is a sectional view schematically showing a beam index type color picture tube device. FIG. 3 is a drawing for explaining the apparatus of the present invention, and FIG. 4 is a sectional view of a main part of a beam index type color picture tube apparatus in which the present invention is implemented. DESCRIPTION OF SYMBOLS 1... Face plate, 4... Index phosphor, 8... Light transmission window, 11... Photodetection element,
12'... Transparent substance, 13... Reflective layer, 14...
Photodetector, R, G, B... three primary color phosphors.

Claims (1)

[Scope of utility model registration request] Electrons emitted by a single electron gun pass through a surface consisting of three primary color phosphor stripes repeatedly arranged on the inner surface of the face plate and index phosphors repeatedly arranged in a striped manner in regular relationship with these three primary color phosphor stripes. In a beam index type color picture tube device in which an optical signal generated from the index phosphor when the beam is swept is guided to an external photodetector through a light transmission window formed on the back surface of the picture tube, a photodetecting element facing the lens; a transparent material disposed between the lens and the photodetecting element and having a refractive index of 0.9 times or more that of the lens; and a transparent substance disposed around the transparent material for effectively transmitting optical signals. A beam index type color image receiver, characterized in that a photodetector comprising a reflective layer tapered from the lens side toward the photodetecting element so as to guide the image to the light transmitting window of the picture tube is attached to the light transmitting window of the picture tube. tube device.