JPS6122538A - Beam-index-type color picture tube - Google Patents

Abstract

PURPOSE:To stably and reliably operate a beam-index-type color picture tube and improve its color purity by making the width of first index phosphor stripes wider than that of adjacent phosphor stripes containing no index phosphors. CONSTITUTION:The width of red phosphor stripes 21 and blue phosphor stripes 22, is adjusted to be half of a conventional width. And, the width of first index phosphor stripes 23 located between the stripes 21 and 22 and made of a phosphor with short afterglow having a luminous peak in the ultraviolet region such as Y2SiO5:Ce, is adjusted to be 3/2 of a conventional width. Becuase the width of the red and blue phosphor stripes is reduced, the width of green phosphor stripes 24 also serving as second index phosphor stripes containing a phosphor such as Y3Al5O12:Ce is adjusted to be 3/2 of a conventional width in order to maintain white balance. By the means mentioned above, it is possible to stably and reliably operate a beam-index-type color picture tube and to improve its color purity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a front-lit 1/m beam index type color picture tube suitable for color electronic viewfinders of video cameras, etc. It is related to the structure of

[Background of the invention]

Conventionally, in front-lighting type beam index tubes that are made smaller by emitting index signals in front of the panel, the 1/rn method, which has a simple structure and reliable color synchronization, and a set of knobs Dm (m is an integer) have been used. Although this method is based on the method of arranging one index phosphor strip for each three primary color phosphor stripes, we have proposed a method that uses two types of index signals so that index signals can be obtained stably. (Japanese Patent Publication No. 58-214253)
.

This is shown in Figure 1, which shows the structure of the fluorescent surface.
A first index phosphor stripe 13 consisting of a short afterglow phosphor having an emission peak in the ultraviolet region is placed between two of the primary colors, for example, a red phosphor stripe 11 and a blue phosphor stripe 12. In addition, a second index phosphor having a short afterglow property and having an emission spectrum similar to that of the green phosphor is mixed with another color, that is, a green phosphor, to produce a second index and green phosphor. A phosphor stripe 14 is formed. For example, for a particular color green for which no index signal is obtained from the first index phosphor stripe, the second index phosphor stripe
Since the index phosphor stripe of the index phosphor emits the index signal with the highest efficiency, the index signal can be obtained by adding the two types of index signals after phase adjustment and using them as one index signal. You can eliminate certain colors that cannot be displayed. However, in this conventional phosphor surface, as is clear from FIG. is the same width W1, for example 35μ
It has m.

In addition, with this unique phosphor surface structure, if the electron beam spot diameter emitted from the electron gun becomes larger than the ideal spot diameter, phosphor stripes of other colors will also be irradiated. For example, if a beam spot with a diameter of 100 μm is irradiated onto the center of the red phosphor stripe 11 in order to reproduce a certain monochromatic red color, the second index green phosphor stripe 14 will emit approximately 20% more light. However, the desired red color is not reproduced and green is mixed in), resulting in a decrease in color purity. Of course, in this case, the arrangement pitch P of one set of three-color phosphor stripes is increased, and the stripe 1
If the gap between the stripe 4 and the stripe 11 or 12 is increased, the above-mentioned deterioration in color purity can be avoided, but in this case, the screen will naturally become coarser and the image quality will deteriorate.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to perform stable and reliable operation using two types of index signals, and to provide a screen with good color purity without making the screen grain coarse. The object of the present invention is to provide a beam index type color picture tube that provides the following properties.

[Summary of the invention]

To achieve this objective, the present invention provides for the width of the first index phosphor stripe to be greater than the width of the adjacent color phosphor stripe that does not include an index phosphor.

[Embodiments of the invention]

Next, an embodiment of the present invention will be described using FIG. 2.

If you compare FIG. 2 with FIG. 1, it is clear that in this embodiment, the width of the red phosphor stripe 21 and the blue phosphor stripe 22 is reduced from the conventional W to V2. The width of the first index phosphor stripe 23 made of a short afterglow phosphor having an emission peak in the ultraviolet region located midway between, for example, Y2SiO5:Ce, was
It is enlarged from 3/2W. In addition, since the stripe widths of the two colored phosphors have been reduced, in order to maintain white balance, a short afterglow phosphor with an emission spectrum close to that of a green phosphor, such as Y8 Giou+:C, is used.
Second index and green phosphor stripe 2 including e
4 has been reduced from the conventional 2W to 3/2W. 1
Arrangement pitch of a set of three-color phosphor stripes p = 210μ
m does not change at all.

Due to this phosphor surface structure, even if the center of the red phosphor stripe 21 is irradiated with an electron beam spot of 100 μm in diameter, the second index green phosphor stripe 24 will not emit light. , a screen with good color purity can be obtained.

Note that the expansion/reduction ratio of each phosphor stripe width is not limited to the above-mentioned values, and may be set as appropriate in consideration of the spot diameter and white balance of the electron beam used.

〔Effect of the invention〕

As described above, according to the present invention, the width of the first index phosphor stripe is made wider than the width of the adjacent color phosphor stripe that does not include the index phosphor. Purity is improved and variations in white chromaticity are reduced, resulting in a high-quality screen. Furthermore, since the width of the first index phosphor stripe is widened, the index signal can be strongly obtained, and there is also the advantage that a stable screen can be obtained even when the current is low.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a fluorescent surface of a conventional beam index type color picture tube, and FIG. 2 is a diagram showing the configuration of a fluorescent surface according to an embodiment of the present invention. 21... Red phosphor stripe, 22... Blue phosphor stripe, 23... First index phosphor stripe, 24.φ Fig. 1 Fig. 2

Claims (1)

[Claims] The phosphor surface formed on the inner surface of the bulb panel consists of regularly repeating colored phosphor stripes that each emit one of the three primary colors, and two colored phosphors in the colored phosphor stripes. a first index phosphor stripe consisting of a short afterglow phosphor having an emission peak in the ultraviolet region formed in the middle of the body stripe so as to be in contact with the two index phosphor stripes; During the stripe,
In a front lighting type 1/m type beam index type color picture tube which is formed by mixing a short afterglow second index phosphor having an emission spectrum close to that of the color phosphor of the one color, A beam index type color picture tube characterized in that the width of the index phosphor stripe is wider than the width of the index phosphor stripe of two adjacent colors.