JPH02267842A - Display tube for light source - Google Patents

Abstract

PURPOSE:To improve the brightness and the contrast of a display by forming the surface portion of the front panel as a matrix of convex lenses corresponding to respective fluorescent display portions provided on the inner surface of the panel and mixing a material attenuating the transmissively of light in the front panel. CONSTITUTION:The surface portion of the front panel 30 of a display tube is formed as a matrix of convex lenses 311-31n corresponding to respective luminous portions 5R, 5G, 5B arranged on the rear surface of the panel in one united body. Thereby the generation of exfoliation of phosphor due to the temperature variation can be eliminated, and the actual distance between a convex lens and the corresponding phosphor display portion can be minimized. Therefore, the reduction of the brightness can be prevented, the lens efficiency can be improved, and the degradation of the image quality can be eliminated even when it is observed obliquely from upside. In addition, a wavelength- selective absorption material (neodymium oxide) attenuating the transmissivity of light is added and mixed to the front panel 30. Thereby the reflection component of outer light on the fluorescent display portion can be suppressed low to minimize the dark luminance and to improve the contrast significantly.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a display tube for a light source used in displays such as large screen display devices and message boards.

[Conventional technology]

In a single-tube element array type large-screen display device, which is constructed by arranging monochrome display tubes in a matrix as one pixel, each pixel uses light emitted from a phosphor. A large non-light-emitting area is generated in the image, making it difficult to improve resolution. Furthermore, as the resolution increases, the number of monochrome display tubes used increases rapidly, leading to increased costs. Therefore, a composite light source display tube has been proposed, for example, as shown in Japanese Patent Laid-Open No. 62-10849. FIG. 3 is a front view showing a display tube for a composite light source as the first conventional example disclosed in JP-A-62-10849, and FIG. 4 is a sectional view taken along the line IV-mV in FIG. 3. . In the figure, ■ is the vacuum envelope of the light source display tube, 2 is the cylindrical side plate of the vacuum envelope 1, 3 is the front panel hermetically sealed to the front surface of the cylindrical side plate 2, and 4 is the cylindrical This is a back panel that is hermetically sealed to the back of the side plate 2, and is connected to the vacuum envelope 1.
consists of a glass tube hermetically sealed by the cylindrical side plate 2, the front panel 3, and the rear panel 4. 5 is the light emitting surface of the front panel 3°, and this light emitting surface 5
Three color light emitting sections (fluorescent display sections) 5R, 5G, and 5B are provided on the back surface of the display panel 1, which emit red, R, G, and blue B colors when irradiated with the electron beam E1. These light emitting parts 5R, 5G, 5B are shown in FIGS. 3 and 4.
In the case of the figure, it consists of phosphors arranged in a matrix of 3×3 pixels. Reference numeral 6 denotes a group of anode electrodes of a light source display tube, and each light emitting section 5R, 5G on the back surface of the front panel 3. It consists of a plurality of accelerating anodes 68.6□... arranged correspondingly around the 5B pixels, and a high voltage is applied to these accelerating anodes 6.6... via the external terminal 16. It is now possible to do so. 7 is a cathode electrode group arranged on the back panel 4 side in the vacuum envelope l, and each of the light emitting parts 5R. It consists of electron-emitting cathodes 7'l 1 to 7, 3 (only 7□ to 7□3 are shown in FIG. 4) independently arranged corresponding to 5G and 5B. These cathodes 7~'713
are supported at both ends between a pair of supports fixed on the back panel 4. Here, the cathode 71. ~7.3 1st. The second subscript corresponds to the first to third rows and the first to third columns. For each of the cathodes 711 to 733, for example, a directly heated external terminal 16 formed by coating an oxide on a Ni sleeve can be used. 8 is a control grid electrode for row selection, and the grid electrode 8 is arranged between the cathode electrode group 7 and the light emitting surface 5.
．． - 84, and these grid electrodes 8I-84 are the respective light emitting parts 5R, 5G. The above cathode 7□ corresponds to 5B in the row direction.
Electron passing hole 9 for passing the electron beam 11 from ~733 as a non-convergent beam. ~93. Reference numeral 10 denotes a back electrode group arranged on the back panel 4, and each of the light emitting parts 5R, 5G, 5 on the back panel 4
It consists of stripe-shaped column selection back electrodes 10I to 103, which are arranged opposite to each other in the column direction corresponding to B. These back electrodes 101 to 103 are connected to the cathode 71. By applying a negative potential and a positive potential of OV or several V to the potential of ~73ff, the cathodes 711 to 7, 3 serve as a control means for controlling the electron beam 11 emitted. Note that 12 is connected to the cathode electrode group 7 from the back panel 4.
．． These are lead wires serving as external terminals that lead out each electrode of the control grid electrode 8 and the back electrode group 10 to the outside. Next, the operation will be explained. First, each back electrode 10, ~
103 is the cathode 71. When the potential is negative with respect to the potential of the cathodes 7.1 to 733, the cathodes 7.1 to 733 are surrounded by a negative potential, so that the irradiated electrons from the cathodes 7. ~84 and acceleration anode 6
1, 6□ . . . does not flow and becomes a cutoff state. Therefore, the cathodes 7□~ are connected to the back electrodes 101~103.
When a positive potential of OV or several square meters is applied to the potential of grid electrode 8. Flows towards ~84. In this case, the grid electrode 8. When the potential of ~84 is negative with respect to the cathodes 711~73°,
Holes 9 for electron passage in each of those grid electrodes 81 to 84.
The electron beam 11 cannot pass through the acceleration anodes 61.6□ . On the other hand, the potential of the grid electrodes 81 to 84 is the same as that of the cathode 7 It~7
: When the potential is positive with respect to 13, the electron passage holes 9 of those grid electrodes S, -S4. ~93 to electron beam 1
1 passes through, each of the light emitting parts 5R,
Lights up 5G and 5B. Therefore, each of the grid electrodes 8I to 84 of the control grid electrode 8 arranged in a matrix and each of the back electrodes 10I to 1 of the back electrode group 10 correspond to the light emitting parts 5R, 5G, and 5B.
By selectively driving and controlling (dynamic driving)
B can be made to emit light. As described above, on the inner surface of the front panel 3 constituting the vacuum envelope 1, there is a light emitting section 5R made of phosphors of three colors. 5G and 5B are arranged in a matrix of 3 x 3 pixels, and a cathode electrode group 7, a control grid electrode 8, and a back electrode group 10 are provided in correspondence with these light emitting parts 5R, 5G, and 5B, thereby achieving high brightness light emission. A display tube for a light source can be obtained. Therefore, when assembling a large screen display device or message board using this light source display tube as one cell, the non-light-emitting area between each pixel will be smaller than when using a single-tube type display tube with one pixel. , which has the effect of improving resolution. Furthermore, since the number of parts and the number of manufacturing steps can be reduced, costs can be reduced. Although the illustrated example shows a case where the light emitting surface 5 made of three-color phosphors is arranged in a matrix of 3×3 pixels on the inner surface of the front panel 3, the present invention is not limited to this.
Phosphor screens each having one phosphor as a pixel are arranged in an arbitrary mXn (where m and n are arbitrary integers) matrix in the vacuum envelope 1, and grid electrode groups and back electrode groups are arranged accordingly. You can also change the configuration. FIG. 5 is a sectional view showing a second conventional example of a light source display tube using a condensing lens array disclosed in Japanese Patent Application No. 63-65879. In the figure, 20 is a filter attached to the surface of the front panel 3 of the vacuum envelope 1 to block light from the outside;
22 is a condensing lens array bonded to the surface of this filter 20 with a transparent adhesive 21 to condense the light emitted from the front panel 3. This condensing lens array 22 includes a base portion 22A and It is composed of a convex lens 22B that is integrally formed on the surface of the base part 22A and corresponds to each of the light emitting parts 5R, 5G, and 5B, and is an integrally molded product by injection molding of acrylic resin. In this manner, in the second conventional example, the luminance of the light emitting section 5R is reduced by the filter 20 because the condenser lens array 22 is provided in front of the filter 20. Since the emitted light from 5G and 5B is condensed by the condensing lens array 22, display brightness can be increased. Furthermore, the external light passes through the filter 20 twice, once when it is incident on the light emitting surface 5 and when it is reflected from the light emitting surface 5.
Since reflected light is greatly attenuated, contrast can be enhanced. Furthermore, when looking at a display screen in which such light source display tubes are combined, the light emitting parts 5R, 5G, 5B
becomes larger due to the enlarging effect of the convex lens 22B, the area of the non-light emitting part between the light emitting part and the light emitting part becomes smaller, equivalently the aperture ratio becomes larger, and the display quality also becomes higher.

[Problem to be solved by the invention]

Since the light source display tubes of the first and second conventional examples are constructed as described above, in the light source display tube of the first conventional example, external light (for example, There is a problem in that the contrast may deteriorate due to the influence of sunlight, etc.). Therefore, there is a method of providing a filter on the surface of the front panel 3 that corresponds to the phosphor screen and transmits only the light of the color emitted by the phosphor screen to reduce the influence of external light and improve the contrast. However, in this method, the light emitted from the phosphor screen also passes through the filter, so there is a risk that the luminance of the emitted light will decrease. The second conventional example has been proposed to avoid such a reduction in luminance. In the second conventional light source display tube, due to temperature changes during use, warping occurs in the condenser lens array 22 due to differences in thermal expansion, and due to this warping, the filter 20 and the front panel 3 and condensing lens array 22 and transparent adhesive 2
There was a problem in that peeling was likely to occur between the two. Further, the condenser lens array 22 for the front panel 3
When the condensing lens array 22 is solidified with the transparent adhesive 21 while being elastically deformed due to the load applied during bonding, stress is generated between the transparent adhesive 21 and the condensing lens array 22, which may cause peeling. become the cause. When peeling occurs in this manner, there is a problem that not only does the brightness decrease due to reflection of light on the peeled surface, but also that when viewed from an oblique direction, the peeled surface undergoes total reflection, making it impossible to see the color. Furthermore, if the pixel pitch of the light source display tube is made smaller to achieve higher resolution and the number of pixels per unit area in the vacuum envelope 1 is increased, the size of each light emitting part 5R, 5G, and 5B becomes smaller. , the front panel 3 needs to have a certain thickness in order to maintain internal vacuum strength, and for this reason, each light emitting part 5R,
There is a problem in that the ratio of the thickness of the front panel 3 to the size of 5G and 5B becomes large. Furthermore, since the condensing lens array 22 integrally molded with acrylic resin is bonded to the surface of the front panel 3, the convex lenses 22 are connected to the light emitting sections 5R, 5G, and 5B depending on the thickness of the base section 22A.
The distance to part B becomes long, and each of the above light emitting parts 5R
, 5G, 5B, the convex lens 2
The proportion of light entering the part 2B becomes smaller and the convex lens 2
2B becomes less efficient, and when the light source display tube is viewed diagonally from above, the light emitting sections 5R, 5G, and 5B are visible through the convex lens 22B, which is located next to the original one, resulting in deterioration of image quality. there were. This invention was made to solve the above-mentioned problems, and it eliminates peeling caused by warping of the condensing lens array due to temperature changes, and shortens the distance between the convex lens and the phosphor screen. To provide a display tube for a light source with high brightness and high contrast, in which light utilization efficiency is improved and pixels and convex lenses are not misaligned even when viewed obliquely from above.

[Means to solve the problem]

In the light source display tube according to the present invention, the surface portion of the front panel, on the inside of which a matrix-like fluorescent display section is arranged, is formed into a matrix-like convex lens corresponding to the fluorescent display section, and the front panel is provided with a light source. It is mixed with a substance that attenuates the transmittance of the light.

[For use]

The light source display tube of the present invention eliminates peeling caused by temperature changes by directly forming a convex lens on the front surface of the front panel, rather than attaching a separate lens to the surface of the front panel. , the substantial distance between the convex lens and the fluorescent display section is shortened. Therefore, the reduction in brightness caused by the peeling mentioned above is eliminated, and the effective distance between the convex lens and the fluorescent display section is short, which improves lens efficiency and prevents deterioration in image quality even when viewed diagonally from above. This makes it possible to display high-quality images without any problems. Furthermore, since the front panel whose surface portion is formed as a convex lens is mixed with a substance that attenuates the transmittance of light as described above, the reflected component of external light at the fluorescent display portion is suppressed to a low level. Dark brightness is reduced and contrast is significantly improved.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view of a display tube for a light source according to an embodiment of the present invention.
FIG. 2 is a front view seen from the convex lens side of FIG. 1, and the same parts as in FIGS. 3 to 5 are denoted by the same reference numerals, and redundant explanation will be omitted. In the figure, 30 is the front panel of the vacuum envelope 1;
The front surface of the front panel 30 has light emitting sections (fluorescent display sections) 5R and 5G arranged on its back side. Matrix-shaped convex lens 312 corresponding to 5B. ~31
It is integrally formed as . Therefore, in other words, the front panel 30 is integrally formed in the shape of a matrix of convex lenses. The front panel 30 can be manufactured by pouring hot molten glass into a carbon-based mold hollowed out into a desired shape and then cooling it, or by placing a carbon-based mold in the shape of a lens array on top of a plate glass. It is produced by passing it through a high-temperature furnace under pressure. A wavelength selective absorbing substance (neodymium oxide) that attenuates the transmittance of light is added to the front panel 30 during manufacture. Next, the operation will be explained. Light emitting section 5 of front panel 30
The light emitted from R, 5G, and 5B passes through a convex lens 311. whose surface portion is integral. ~31. It moves forward through the front panel 30 which has become
1. ~31. ．． The optical path is bent in accordance with the curvature of the light, and the light is focused as a whole, thereby improving brightness. On top of that,
Due to the lens characteristics (enlargement effect) of the convex lenses 311, 31, the sizes of the light emitting sections 5R, 5G, 5B are increased, and the aperture ratio is increased, thereby improving the image quality. Here, the convex lens 311. ~31. ．． Since neodymium oxide is added to the front panel 30, the emitted light corresponding to its absorption spectrum is attenuated. However, the spectrum of neodymium and each of the above light emitting parts 5
Since the emission spectra of R, 5G, and 5B are different, the brightness attenuation is slight. On the other hand, external light that leads to a decrease in contrast passes through the front panel 30 and reaches each light emitting section 5R. After entering the fluorescent screens of 5G and 5B and being reflected there, the front panel 30 and the convex lens 31. .about.31, and passes through the convex lens 311. ~31. ．． is emitted from the surface of However, the neodymium added to the front panel 30 greatly attenuates the spectrum of the part of the spectrum contained in external light that is sensitively perceived by the human eye as brightness, thereby suppressing dark brightness. Therefore, the contrast is significantly improved. In the above embodiment, although the control means for controlling the light emission of the light emitting sections 5R, 5G, and 5B was not illustrated, this control means is the same as in the conventional example.

【Effect of the invention】

As described above, according to the present invention, instead of attaching a separate lens to the front panel of the light source display tube, the front panel surface portion is formed as an integral convex lens. Convex lens (condensing lens)
There is no risk of peeling between the front panel and the front panel, and the substantial distance between the convex lens and the fluorescent display section is shortened. Therefore, the light emitted from the fluorescent display section can be efficiently incident on the convex lens, and even when the light source display tube is viewed diagonally from above, the light emitting section cannot be seen from the convex lens located next to the original convex lens. This has the effect that it is possible to display high-quality images by eliminating such problems. In addition, as mentioned above, the front panel, whose surface portion is formed as a convex lens, is mixed with a substance that attenuates the transmittance of light, so that the attenuation of the emitted light is kept to a minimum, and the brightness improvement effect of the convex lens allows for high brightness. Light emission can be ensured, and the external light component has a large attenuation rate and is attenuated twice, once when it is incident and when it is reflected, so that the dark brightness is reduced and the contrast is significantly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a light source display tube according to an embodiment of the present invention, FIG. 2 is a front view as seen from the convex lens side of FIG. 1, and FIG.
The figure is a front view showing the light source display tube of the first conventional example, FIG. 4 is a sectional view taken along the line ■-rV in FIG. 3, and FIG. 5 is a sectional view showing the light source display tube of the second conventional example. . ■...Vacuum envelope, 5R, 5G, 5B...Light emitting part (
fluorescent display section), 30...front panel, 311. ~31
,···convex lens. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. 1n Now 1, Vacuum envelope 5R, 5G, 5B: 7 p (Cao Yu table original creation 30-Front panel 311-31n: cl. Light source display tube representative (voluntary) 5. Subject of amendment (1) Claims column of the specification (2) Detailed explanation of the invention column of the specification 6. Contents of amendment (1) Claims Correct the range as shown in the attached sheet. (2) "Acceleration anode 6.6" on page 3, line 12 of the specification.
The text has been corrected to read "acceleration anodes 6□, 6□." (3) On page 4, line 5 of the specification, it says, "A direct heating type with 16 external terminals can be used." ” he corrected. (4) “Next to the original take” on page 11, line 15 of the specification
(5) In the 4th line of page 12 of the specification, the statement ``Obtaining a display tube for a light source with high brightness and high contrast'' has been changed to ``High quality. To obtain a display tube for a light source capable of displaying an image of.'' (6) In the 9th line of page 12 of the specification, the phrase ``The surface portion is mixed with...'' was replaced with ``The surface portion is formed into a matrix-shaped convex lens corresponding to the fluorescent display section.'' It was corrected as follows. (7) Delete the statement ``In addition, as described above...significant improvement'' from line 4 to line 9 of page 13 of the specification. (8) From page 16, line 19 to page 17, line 6 of the specification: ``In addition, as described above, there is an effect.''
Delete a certain entry. 7. List of attached documents A document stating the scope of claims after amendment One or more copies of amended claims A vacuum envelope having a front panel and arranged in a matrix inside the front panel A display tube for a light source comprising a plurality of fluorescent display sections and a control electrode for controlling light emission of these fluorescent display sections, characterized in that the surface section of the front panel is formed into a matrix-like convex lens. display tube.

Claims (1)

[Claims] A light source display tube comprising a vacuum envelope having a front panel, a plurality of fluorescent display sections arranged in a matrix inside the front panel, and a control electrode for controlling light emission of these fluorescent display sections. A display tube for a light source, characterized in that a surface portion of the front panel is formed into a matrix-like convex lens, and a substance that attenuates light transmittance is mixed into the front panel.