JPH0927284A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube capable of high-quality display by enhancing the brightness and contrast characteristics of an effective display screen and the color purity of display light in each color. SOLUTION: A color filter layer 20 provided between the inner surface of a faceplate 12 and a phosphor screen 18 has filters of three colors, opposed to the phosphor layers of three colors R, G, B of the phosphor screen, with the three colors corresponding to the phosphor layers of these colors. The filter for each color is so formed that its transmission factor for light of wavelengths in the range ±20nm of the maximum emission spectrum wavelength of the light emitted from the phosphor layer of the corresponding color is made higher than that for light of wavelengths between 400nm and 650nm and outside the above range. A common outer-surface filter 22 which has maximum absorption in a predetermined wavelength band outside the range ±20nm of the maximum emission spectrum wavelength of the phosphor layers of the three colors and which supplements the light absorption property of the color filter layer is formed over the outer surface of the faceplate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to a color cathode ray tube which realizes high brightness and high contrast display.

[0002]

2. Description of the Related Art Generally, a color cathode ray tube which has been put into practical use is generally a translucent face plate having an effective display area for displaying an image and an inner surface side of the effective display area of the face plate. And a funnel, the front end of which is joined to the back side of the face plate to form a sealed envelope as an outer shell of the color cathode ray tube together with the face plate. A funnel-shaped taper is formed at the rear end of the funnel, and an electron gun for projecting an electron beam onto the phosphor screen at a position corresponding to a display image while scanning the electron beam is arranged inside the neck.

The trajectory of the electron beam emitted from the electron gun is controlled by a magnetic field generated by a deflection yoke arranged so as to surround the path of the electron beam, and projected onto a predetermined position on the phosphor screen.

An important characteristic of the image display quality of the color cathode ray tube is the characteristic of the brightness of the displayed image. The brightness of this image is generally evaluated by the high brightness and the high contrast ratio.

The brightness and contrast of an image displayed on the screen which is visually perceived by an observer is not only dependent on the height of the brightness of the displayed image, but also on the surface brightness of the display screen itself. Dependent. In other words, the display visually recognized by the observer is a combination of the sum of the reflected light and the visible brightness of the phosphor screen itself when the screen is not displayed, and the brightness of the display image emitted by the phosphor screen. The brightness and contrast of the image are determined.

By improving the brightness and contrast of such a display image, the image display quality of the color cathode ray tube can be improved. However, the conventional technique has a problem that it is difficult to improve both brightness and contrast at the same time.

That is, by selecting the material of the face plate and improving the light transmittance of the face plate,
The light emitted from the phosphor screen and emitted to the front surface of the face plate can be effectively used with a high transmittance, and the displayed image can be viewed brightly.

However, when a face plate made of a material having a high light transmittance is used, the brightness of the screen during non-display is generally high due to the brightness of the phosphor screen itself in the non-light emitting state. The contrast of the image displayed by exciting the phosphor screen to emit light is determined by the relative relationship between the brightness of the displayed image and the brightness of the screen when there is no display, and the brightness of the screen when there is no display is high. The lower the contrast characteristic of the displayed image becomes. Since the phosphor screen itself is generally white in color, the brightness is extremely high. Therefore, when a face plate having a high light transmittance is used, the contrast ratio of the displayed image tends to decrease.

Therefore, in the conventional color cathode ray tube, in order to improve the brightness of the displayed image, the driving voltage of the color cathode ray tube is increased to increase the energy of the electron beam and the emission brightness of the phosphor is increased. That policy is generally adopted.

Further, conventionally, in order to improve the contrast characteristics, the material of the face plate is made of colored glass to reduce the light transmittance thereof to, for example, 40% or less, thereby suppressing the brightness of the screen during non-display. That is, a method in which a pigment is mixed into the phosphor to darken the color of the phosphor screen itself is generally adopted.

However, when the electron beam energy is increased, the power consumption of the entire color cathode ray tube increases,
Not economically favorable. Further, when the material of the face plate is colored glass and the light transmittance thereof is reduced to, for example, 40% or less, the brightness of the display image decreases in proportion to the light transmittance of the face plate, while Since the light reflectance decreases in proportion to the square of the light transmittance of the face plate, the contrast characteristic of the display image improves. However, if the light transmittance of the face plate itself decreases, the light transmittance of light emitted from the phosphor layer and forming an image through the face plate also decreases to 40% or less. As a result, there arises a problem that the brightness of the display image is significantly reduced.

In recent years, in order to flatten the face plate, there has been provided a color cathode ray tube having a shape in which the glass thickness of the face plate increases from the center of the screen to the peripheral portion at a predetermined rate of change. . In this type of color cathode ray tube, the peripheral portion of the face plate, which has a large wall thickness, has a high absorptance of the light forming the display image, so that the peripheral portion of the screen and the central portion of the screen have significantly different brightness of the display image. There is a problem.

In the flattened color cathode ray tube, it is necessary to make the thickness of the face plate uniform over the entire screen so that the shape of the shadow mask provided therein, the scanning method of the electron beam, and the entire color cathode ray tube. There is a problem that it is extremely difficult to realize in practice because there are many restrictions on the manufacturing method and the structure because it is necessary to specialize the manufacturing method.

It is also possible to improve the contrast characteristics by mixing a pigment in the phosphor to darken the color of the phosphor screen itself, but since the pigment is not a phosphor, it does not emit light in the phosphor layer. The proportion of the composition that does not contribute increases, and the luminous efficiency of the phosphor layer itself decreases. As a result, there is a problem in that the brightness of the display image is reduced.

It is also conceivable to further increase the voltage for emitting the electron beam from the electron gun to increase the energy of the electron beam and further increase the light emission in the phosphor layer. However, in this case, the power consumption further increases, and the voltage for deflecting the electron beam of high energy also needs to be high, which leads to an increase in the power consumption, and as a whole, the power consumption of the color cathode ray tube as a whole is reduced. There is a problem that it will increase significantly.

Therefore, in order to solve the above problems, a technique of inserting a color filter layer between the inner surface of the face plate and the phosphor screen has been proposed and has been attracting attention in recent years.

This color filter layer has a plurality of color filters provided so as to face phosphor dots or phosphor stripes forming pixels of each color of the phosphor screen, and each color filter has pixels of opposite colors. Only the light of the emission color of is transmitted. Such a color filter layer emits only the light emission corresponding to the emission color of each pixel to the face plate side, while preventing reflection of external light at the boundary surface between the phosphor screen and the face plate. Therefore, it is considered that the contrast characteristic can be effectively improved without lowering the chromaticity of the bright spot for each color of the screen, in other words, without lowering the color purity of the light emission and the luminance thereof. .

[0018]

However, since such a color filter layer is disposed on the inner surface of the face plate, its material is heat resistant and transparent enough to withstand the environment inside the color cathode ray tube. It is limited to what is provided, for example, an inorganic pigment. Due to such material restrictions, it is not always possible to set the filter characteristics of the color filter layer to the most preferable characteristics, and there is a problem that the filter function is not sufficient.

That is, of the bright spots of each color forming the image displayed on the screen, red (R) is a color that most significantly affects the reproduction quality of the image. This R
The spectrum of the red light emitted from the bright spot, that is, the phosphor corresponding to red, shows an extremely narrow and steep distribution, and the color purity of the color development of the R bright spot is displayed if the spectrum is displayed as it is. It will be preferable.

However, when the color filter layer as described above is used, the R bright spot displayed on the screen is displayed as light of a color that is close to the spectrum of the red light emitted from the phosphor to a certain extent. However, at present, due to the characteristics of the color filter layer, a large subband exists in the emission spectrum of the R bright spot. Therefore, there is a problem that the R bright spot of the image displayed on the screen is visually perceived by an observer as having deteriorated color purity. Such a problem of color purity occurs not only in red (R) but also in green (G) and blue (B).

As described above, in the conventional color cathode ray tube,
There has been a problem that it is difficult to achieve both sufficient improvement of the brightness and contrast characteristics of the effective display screen and improvement of the lightness and color purity of the bright spots of each color such as red in the display image.

The present invention has been made in view of the above points, and an object thereof is to improve the brightness and contrast characteristics of an effective display screen and the color purity at the same time, thereby enabling high quality display. It is to provide a color cathode ray tube.

[0023]

In order to solve the above problems, a color cathode ray tube according to the present invention according to claim 1 is
An envelope including a face plate having an outer surface and an inner surface, and a funnel joined to the face plate and having a neck, and an envelope provided on the inner surface of the face plate and arranged in a predetermined pattern. A phosphor screen having phosphor layers of three colors, an electron gun provided in the neck for irradiating the phosphor screen with an electron beam to emit light, and between the inner surface of the face plate and the phosphor screen. A color filter layer provided in the phosphor screen, the phosphor screen being arranged to face at least one color phosphor layer of the phosphor screen, and having a maximum emission spectrum wavelength of ± 20 nm of the light emission from the one color phosphor layer. The transmittance for light having a wavelength in the range of 400 to 650 nm is the transmittance for light having a wavelength outside the above range. A color filter layer as compared to the rates and a high color filters on the outside of the color filter layer is provided so as to face the color filter layer, ± 20n of the maximum emission spectrum wavelength of the phosphor layer of the one color
The correction means has a maximum absorption in a predetermined wavelength band other than the range of m and complements the light absorption of the color filter.

A color cathode ray tube according to a second aspect of the present invention is an envelope including a face plate having an outer surface and an inner surface, and a funnel joined to the face plate and having a neck. A phosphor screen provided on the inner surface of the face plate and having phosphor layers of three colors of red, green and blue arranged in a predetermined pattern, and provided in the neck,
An electron gun that irradiates the phosphor screen with an electron beam to emit light, is provided between the inner surface of the face plate and the phosphor screen, and faces the phosphor layers of the three colors of the phosphor screen. A color filter layer having three color filters corresponding to the respective color phosphor layers, and each color filter has a maximum emission spectrum wavelength of the light emission from the corresponding color phosphor layer. A color filter layer having a transmittance of light having a wavelength of ± 20 nm higher than that of light having a wavelength of 400 to 650 nm and having a wavelength other than the above range; and an outer side of the color filter layer. Is provided so as to face the color filter layer, and has maximum absorption in a predetermined wavelength band other than the range of ± 20 nm of the maximum emission spectrum wavelength of the phosphor layers of the above three colors. And a correction unit that complements the light absorption of the color filter.

According to the present invention, the correcting means includes an outer surface filter formed on the outer surface of the face plate. Further, according to another color cathode ray tube of the present invention, the face plate is made of neodymium glass and constitutes the correcting means.

The face plate has a substantially rectangular shape, and has a wall thickness that increases from the center to the peripheral portion at a predetermined rate of change. According to the color cathode ray tube of the present invention configured as described above, the external light is absorbed to the first order by the correction means provided so as to face the color filter layer. Then, the external light transmitted through the face plate without being absorbed by the correction means is absorbed by the color filter of the color filter layer formed on the inner surface of the face plate, and the light of the color component other than the emission of the phosphor of at least one color is absorbed. To be done. This is the secondary absorption of external light.

Further, the external light which is not absorbed even by the secondary external light absorption is re-entered into the color filter layer and absorbed when reflected on the surface of the phosphor screen and returning to the front surface. This is the third order external light absorption. Then, the external light remaining without being absorbed even by the third external light absorption is again absorbed by the correction means. This is the fourth order external light absorption.

Due to the first to fourth order external light absorption, the external light reflected by the face plate of the color cathode ray tube is very effectively absorbed. On the other hand, light of each color from the phosphor for forming the display image can be transmitted through each color filter of the color filter layer with high transmittance. Therefore, the inventor of the present invention has confirmed by various experiments that an image having a high contrast ratio and high brightness can be displayed to human eyes.

Therefore, both improvement of the contrast characteristic of the display screen and improvement of the luminance can be realized without depending on the light absorption of the face plate itself. The color filter of the color filter layer and the correction means can absorb the sub-band portion of the light emission of at least one color.
The color purity of the color is also improved.

Further, not only the above first to fourth order external light absorption is simply combined to improve the contrast and brightness, but also the color picture tube of the present invention is
The spectrum distribution of the display light of the bright spots of each color of the display image can be made closer to the emission spectrum distribution of the phosphor of the corresponding color than before. Therefore, the color reproducibility of the display image is also good. That is, the sub-band of the display light of each color can be made narrower than in the conventional case, and a high-quality color image with higher color purity can be displayed.

Further, even in a so-called flattened color cathode ray tube having a shape in which the effective display screen of the face plate increases from the center to the peripheral portion at a predetermined rate of change, the contrast characteristics and brightness of the display screen are improved. It is possible to achieve both of the above, and to make the brightness and contrast characteristics uniform from the central portion to the peripheral portion.

[0032]

DETAILED DESCRIPTION OF THE INVENTION A color cathode ray tube according to an embodiment of the present invention will be described in detail with reference to the drawings. First, the overall configuration of the color cathode ray tube will be schematically described. As shown in FIG. 1, the color cathode ray tube includes a substantially rectangular face plate 12 and a funnel-shaped funnel 14 which form a sealed envelope 10. The face plate 12 is provided with a rectangular effective display area 12a for displaying an image, and is formed so that the wall thickness increases from the center of the screen toward the periphery at a predetermined rate of change, and the outer surface of the face plate 12 is almost the same. It is formed flat.

The front end of the funnel 14 is joined to the peripheral edge of the face plate 12 on the back side. Also,
The rear end of the funnel 14 is tapered to form a neck 16.

On the inner surface of the face plate 12, a phosphor screen 18 having phosphor layers of three colors of red, green and blue is formed facing the effective display area 12a. In addition, the inner surface of the face plate 12 and the phosphor screen 1
A color filter 20 is provided between the color filters 20 and 8. Further, a common outer surface filter 22 that functions as a correction unit is formed on the outer surface of the face plate 12 so as to cover the effective display area 12a.

A phosphor screen 18 is provided in the envelope 10.
A shadow mask 24 is disposed so as to face the. An electron gun 26 that irradiates the phosphor screen 18 with the electron beam A through the shadow mask 24 is provided inside the neck 16 of the funnel 14. Funnel 14
A deflection yoke 30 is mounted on the outer peripheral surface of the electron beam A, and the electron beam A emitted from the electron gun 26 is deflected in the horizontal and vertical directions by the magnetic field formed by the deflection yoke to scan the phosphor screen 18.

On the other hand, the face plate 12 is made of glass having a high transmittance, which looks like a gray color having a transmittance of 65%. Therefore, the light of the display image is absorbed by the face plate 12 by about 35%, but the brightness of the visually recognized display image is not significantly reduced.

As shown in FIG. 2, the phosphor screen 18
The red, green, and blue phosphor layers R, G, and B are formed in a stripe shape and arranged in parallel with each other. The film thickness of the phosphor screen 12 is formed to about 5 to 20 μm. The phosphor layers R, G, B of the respective colors are not limited to the stripe shape and may be formed in the dot shape.

On the inner surface of the face plate 12, a light shielding layer (black matrix) 34 made of a black pigment is formed.
Is provided and faces the gap portion between the adjacent phosphor layers of the phosphor screen 18. The thickness of the light shielding layer 34 is 0.
It is set to about 5 to 1.0 μm. In addition, the light shielding layer 3
The black pigment used in No. 4 has an average particle size of 0.2 to 0.5.
Black particles of about μm, for example, graphite particles can be preferably used.

Face plate 12 and phosphor screen 1
The color filter layer 20 provided between the color filter layer 8 and the color filter layer 8 includes a red filter R, a green filter G, and a blue filter B formed in stripes, respectively, and these filters are arranged in parallel with each other. . Further, the red filter R, the green filter G, and the blue filter B are formed and arranged so as to face the phosphor layers R, G, and B of the corresponding colors of the phosphor screen 18, respectively. This color filter 20
Has a thickness of about 0.05 to 1.0 μm.

When the phosphors of the respective colors of the phosphor screen 18 are formed in the dot shape, the filters of the respective colors of the color filter layer 20 are correspondingly formed in the dot shape.

Here, preferred examples of the pigment used in the color filter layer 20 will be described below. That is, in the present embodiment, each color filter R, G, B of the color filter layer 20 is formed using a pigment having an average particle size of 0.0001 to 0.07 μm.

The pigment used for the red filter R is a ferric oxide pigment, trade name: Sicotrans Red L-2.
817 (particle size 0.01 to 0.02 μm, manufactured by BASF), anthraquinone-based pigment, trade name Chromophartal Red A2B (particle size 0.01 μm, manufactured by Ciba Geigy), and the like are preferably used. You can

The pigment used for the green filter G is Ti.
O ₂ is a -NiO-CoO-ZnO-based pigments, trade names die Piroki side TM Green No. 3320 (particle size 0.
01~0.02μm, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), CoO-Αl ₂
O ₃ -Cr ₂ O ₃ -TiO is a _two-based pigments, trade names die Piroki side TM Green No. 3340 (particle size 0.0
1 to 0.02 μm, manufactured by Dainichiseika Co., Ltd., CoO-Al ₂ O
Trade name Firstgen, which is a _3- Cr ₂ O ₃ -based product name Dipiroxide TM Green No. 3420 (particle diameter 0.01 to 0.02 μm, manufactured by Dainichiseika), a chlorinated phthalocyanine green-based pigment Green S (particle size 0.
01 μm, manufactured by Dainippon Ink and Co., Ltd., and a brominated phthalocyanine green pigment, trade name Fastgen Green 2YK (particle diameter 0.01 μm, manufactured by Dainippon Ink and Chemicals, Inc.) and the like can be preferably used.

The pigment used for the blue filter B is a cobalt aluminate (Al ₂ O ₃ —CoO) pigment, trade name Cobalt Bull-X (particle diameter 0.01 to 0.0).
2 μm, manufactured by Toyo Pigment Co., Ltd., and a phthalocyanine blue-based pigment such as trade name Rionol Blue FG-7370 (particle diameter 0.01 μm, manufactured by Toyo Ink Co., Ltd.) can be preferably used.

The common outer surface filter 22 formed on the outer surface of the face plate 12 is provided so as to face the filters R, G, B of the respective colors of the color filter layer 20 in common. The common outer surface filter 22 is 0.01 to 0.
It is formed with a film thickness of 05 μm and is formed of silicon containing an organic pigment or dye. As the organic pigment, for example, an indium pigment,
Further, as the dye, for example, a rhodamine-based dye or a xanthene-based dye can be preferably used.

The color filter layer 20 and the common outer surface filter 22 configured as described above have filter characteristics as shown in FIGS. 3A to 3C, that is, light transmission and absorption characteristics. In FIG. 3A, the dashed-dotted curve (a) shows the absorption spectrum of the blue filter B in the color filter layer 20, and the broken-line curve (b) shows the absorption spectrum of the common outer surface filter 22. The filled portion shows the emission spectrum distribution of the blue phosphor.

As can be seen from FIG. 3A, the blue filter B is ± 20n of the maximum emission spectrum wavelength of the blue phosphor.
It has a transmittance of 70% or more for light in the range of m, for example, light near a wavelength of 450 nm, and conversely for light in other bands, that is, light in the wavelengths of the emission spectrum bands of green and red. It has a transmittance of about 40% and strongly absorbs external light near this band. In particular, the average transmittance for light having a wavelength of 500 to 600 nm is about 5 to 65%.

As described above, the blue filter B is formed so as to efficiently transmit light in the emission spectrum band of the facing blue phosphor layer B and selectively absorb light in other bands.

On the other hand, the common external filter 22 has maximum absorption in the wavelength band of 500 to 600 nm, which has the highest luminosity factor of the human eye, more specifically, in the wavelength band of 575 ± 20 nm, and the light of the wavelength in this band is absorbed. Has a transmittance of 50 to 90%. Therefore, the common outer surface filter 22 selectively absorbs external light in a band having high visibility and efficiently transmits light in other bands.

By combining the blue filter B and the common outer surface filter 22 as described above, the filter characteristics of the blue filter are corrected by the common outer surface filter.
The absorption spectra of both filters are closer to the emission spectrum distribution of the blue phosphor as shown by the solid curve (c) in FIG. It is possible to reduce the transmittance of external light in a highly sensitive band and efficiently absorb this external light. At the same time, it is possible to absorb the sub-band portion of the phosphor that emits blue light.

In FIG. 3B, the dashed-dotted curve (a) shows the absorption spectrum of the green filter G in the color filter layer 20, and the broken-line curve (b) shows the absorption spectrum of the common outer surface filter 22. The black filled portions show the emission spectrum distribution of the green phosphor.

As can be seen from FIG. 3B, the green filter G has a maximum emission spectrum wavelength of the green phosphor of ± 20 n.
It has a transmittance of 70% or more for light in the range of m, for example, light in the vicinity of a wavelength of 530 nm, and conversely, for light in the wavelengths of other bands, that is, blue and red emission spectrum bands. It has a transmittance of about 40% and strongly absorbs external light near this band. In particular, the average transmittance for light having a wavelength of 500 to 600 nm is about 5 to 65%.

As described above, the green filter G is formed so as to efficiently transmit the light in the emission spectrum band of the facing green phosphor layer G and selectively absorb the light in the other band.

When such a green filter G and the common outer surface filter 22 are combined, the common outer surface filter corrects the filter characteristics of the green filter, and the absorption spectrum of both filters is shown by the solid line in FIG. 3 (b). As shown by the curve (c) in Fig. 1, the light emission spectrum distribution of the green phosphor approaches, and the transmittance for the green display light is hardly reduced, and the transmittance for the external light in the high visibility band is reduced. It becomes possible to absorb light efficiently. At the same time, it is possible to absorb the green-emitting subband portion of the phosphor.

In FIG. 3C, the dashed-dotted curve (a) shows the absorption spectrum of the red filter R in the color filter layer 20, and the broken-line curve (b) shows the absorption spectrum of the common outer surface filter 22. The black filled portion shows the emission spectrum distribution of the red phosphor.

As can be seen from FIG. 3 (c), the red filter R is ± 20n of the maximum emission spectrum wavelength of the red phosphor.
It has a transmittance of 70% or more for light in the range of m, for example, light in the vicinity of a wavelength of 627 nm, and conversely, for light in other bands, that is, light of wavelengths in the emission spectrum bands of blue and green. It has a transmittance of about 40% and strongly absorbs external light near this band. In particular, the average transmittance for light having a wavelength of 500 to 600 nm is about 5 to 65%. In this way, the red filter R is formed so as to efficiently transmit light in the emission spectrum band of the red phosphor layer R facing it and selectively absorb light in other bands.

By combining the red filter R and the common outer surface filter 22 as described above, the filter characteristics of the red filter are corrected by the common outer surface filter, and the absorption spectrum of both filters is shown by the solid curve in FIG. As shown in (c), the emission spectrum distribution of the red phosphor becomes closer, and the transmittance for the red display light is hardly reduced, and the transmittance for the external light in the band with high visibility is reduced. It becomes possible to absorb efficiently. At the same time, the red-emitting subband portion of the phosphor can also be absorbed.

In the color cathode ray tube constructed as described above, the external light incident on the face plate 12 is
It is absorbed by the common outer surface filter 22 common to the filters of the respective colors. This will be called first-order absorption. The primary absorption absorbs about 5 to 35% of external light.

The light transmitted through the face plate 12 without being absorbed by the common outer surface filter 22 is caused by the color filter layer 20 formed on the inner surface side of the face plate.
Each color phosphor layer absorbs light of a color component other than the emission of that color. This is the secondary absorption of external light, and about 5 to 60% of the external light remaining at this time is further absorbed by the color filter layer.

The external light which is not absorbed even by the secondary external light absorption is reflected by the surface of the phosphor screen 18 and returns to the face plate 12 side, and re-enters the color filter layer 20 and is absorbed. . This is the third-order external light absorption,
About 15 to 60% of the outside light remaining at this time is further absorbed.

Further, the external light which is not absorbed even by the third external light absorption is again absorbed by the common external filter 22. This is the fourth order external light absorption, and about 5 to 35% of the external light remaining at this time is further absorbed.

Due to the first to fourth order external light absorption, the external light reflected on the outer surface and the inner surface of the face plate 12 of the color cathode ray tube can be absorbed very effectively. On the other hand, the light of each color of the display image formed by the light emission of the phosphor screen 18 is transmitted through the color filter layer 2
The filters R, G, B of the corresponding color of 0 and the common outer surface filter 22 can be transmitted with high transmittance. Therefore, it is possible to display an image in which the human eye feels that the contrast ratio is high and the brightness is high.

In order to confirm the effect of improving the contrast ratio and the brightness as described above, the present inventors have provided a color cathode ray tube (d) according to the present embodiment equipped with a color filter layer 20 and a common outer surface filter 22, A color cathode ray tube having another structure, that is, a color cathode ray tube (a) having no filter, a color cathode ray tube (b) having only an outer surface filter, and a color cathode ray tube (c) having only a color filter layer. We compared and examined.

FIG. 4 shows the relationship between the relative luminance and the relative outside light reflectance on the effective display screen of these color cathode ray tubes, and FIG. 5 shows the luminance and contrast of the observed display image of these color cathode ray tubes. The results of comparison are shown.

In FIG. 4, the dashed-dotted curve (a) is
The characteristics of the color cathode ray tube (a) whose contrast is improved by making the light transmittance of the face plate lower than that of the present embodiment, and the broken line curve (b) shows that of the color cathode ray tube (b) having only the outer surface filter. A characteristic, a two-dot chain line curve (c) shows a characteristic of the color cathode ray tube (c) having only the color filter layer, and a solid line curve (d) shows a characteristic of the color cathode ray tube according to the present embodiment. .

In FIG. 5, the luminance (B), reflectance (R), contrast (B / R), and color reproduction range are
The value of the color cathode ray tube (a) is used as the reference (100
%), Color cathode ray tubes (b) and (d)
Each value of is shown. In the contrast column, the values shown in parentheses are the values when the color cathode ray tube (b) is used as a reference.

As can be seen from these figures, in the case of the color cathode ray tube having no filter, both the brightness and the contrast are the lowest. The color cathode ray tube (b) provided with only the common outer surface filter has an improved contrast, but is not yet sufficient, and the brightness also decreases, as compared with the color cathode ray tube (a).

In the case of the color cathode ray tube (c) having only the color filter layer, as shown by the curve (c), the relative luminance is also low in the region where the relative reflectance is low, so that the contrast characteristic is improved. Then, the brightness decreases.

On the other hand, in the case of the color cathode ray tube according to the present embodiment, as shown by the curve (d), a region having a low relative reflectance, which is sufficiently effective for improving the image quality, that is, the relative reflectance. It can be seen that in a region of 40% or less, the relative brightness is sufficiently high, and both improvement in contrast characteristics and improvement in brightness can be realized.

Further, not only the above-mentioned first to fourth order external light absorption is simply combined to improve the contrast and the brightness, but also in the color cathode ray tube of the present embodiment, By using the layer and the common outer surface filter in combination, the absorption spectrum distributions of both filters with respect to the emission bright points for each color can be made closer to the emission spectrum distribution of the phosphor itself corresponding to each color.

For example, the spectrum distribution of the R bright spots of the display image can be made closer to the steep emission spectrum distribution of the red phosphor itself than in the conventional case, and as a result, the red color development in the display image becomes higher than that in the conventional case. Can be visually recognized as a dramatically high color purity. This can be seen clearly from FIG. 3 (c).

That is, as shown by the solid curve C in FIG. 3 (c), the filter characteristic in the case where the red filter and the common external filter are combined, that is, the absorption spectrum is more than that in the case where only the red filter is used. It can be seen that the steepness is significantly increased, and that the emission spectrum of red (R), which shows an extremely steep spectrum distribution, is considerably close to that. Then, by using a filter having such an absorption spectrum, it selectively absorbs light in a wavelength range other than red light emission, including the sub-band of red light emission, and the color purity of the display light of the red bright spot on the display screen. Can be significantly improved.

As is clear from FIGS. 3A and 3B, the effect of improving the color purity of the display light, in other words, bringing the spectrum distribution of the display light closer to the emission spectrum distribution of the phosphor is red. Not only can green and blue be obtained in the same manner. Thereby, the color reproducibility can be improved.

Therefore, according to the present embodiment, the contrast characteristics and the brightness of the display image are both improved, and further,
It is possible to provide a color cathode-ray tube that realizes high-quality color image display in which the R, G, and B colors are dramatically improved in purity.

Further, the effective display area 12a of the face plate 12 is formed in a shape in which the wall thickness increases from the center to the peripheral portion at a predetermined rate of change and is so-called flattened. Both improvement of the contrast characteristic and improvement of the luminance can be achieved, and the luminance and the contrast characteristic can be made uniform from the central portion to the peripheral portion of the display screen.

The present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the present invention. For example, the correction unit that corrects the characteristics of the filters of the respective colors of the color filter layer is the common outer surface filter 2 described above.
The face plate 12 itself may be used as the correction means. In this case, as shown in FIG.
The common exterior filter is removed, and instead the faceplate 12 is formed of neodymium glass.

As shown in FIG. 7, the face plate 12 made of neodymium glass has maximum absorption in the band near the wavelength of 575 nm at which human visual sensitivity is high and other wavelength bands as in the common outer surface filter described above. 6 for the light of
It has a transmittance of 0% or more. Also in the color cathode ray tube configured as described above, the same operational effect as that of the above-described embodiment can be obtained.

[0078]

As is clear from the detailed description above, according to the present invention, both the sufficient improvement of the brightness of the effective display screen and the sufficient improvement of the contrast characteristics are achieved, and the display light of each color is It is possible to provide a color picture tube that can improve color purity and realize high-quality display.

[Brief description of drawings]

FIG. 1 is a sectional view of a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a part of a face plate of the color cathode ray tube.

FIG. 3 is a characteristic diagram showing light absorption spectra of blue, green, and red color filters in the color cathode ray tube together with light absorption spectra of a common outer surface filter.

FIG. 4 is a characteristic diagram showing the relationship between relative luminance and relative external light reflectance in the color cathode ray tube and a plurality of other color cathode tubes.

5A and 5B are views showing various characteristics of various color cathode ray tubes shown in FIG. 4 in comparison.

FIG. 6 is a sectional view showing a face plate of a color cathode ray tube according to another embodiment of the present invention.

FIG. 7 is a characteristic diagram showing a light absorption spectrum of neodymium glass.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Envelope 12 ... Face plate 12a ... Effective display area 14 ... Funnel 18 ... Phosphor screen 20 ... Color filter 22 ... External common filter 24 ... Shadow mask 26 ... Electron gun 30 ... Deflection yoke R, G, B ... Fluorescence Body layer, color filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoko Nakazawa 1-9-2 Harara-cho, Fukaya-shi, Saitama Stock company Toshiba Fukaya electronics factory

Claims (9)

[Claims] 1. An envelope having a face plate having an outer surface and an inner surface, a funnel joined to the face plate and having a neck, and an envelope provided on the inner surface of the face plate and having a predetermined shape. , A phosphor screen having phosphor layers of three colors arranged in a pattern, an electron gun provided in the neck for irradiating the phosphor screen with an electron beam to emit light, and an inner surface of the face plate and the phosphor. A color filter layer provided between the phosphor screen and the body screen, the maximum emission among the light emitted from the phosphor layer of the one color which is arranged to face the phosphor layer of at least one color of the phosphor screen. The transmittance of light having a wavelength in the range of ± 20 nm of the spectral wavelength is 400 to 650 nm, and the wavelength is outside the above range. A color filter layer having a color filter higher than the light transmittance, and a maximum emission spectrum wavelength of the one-color phosphor layer provided outside the color filter layer and facing the color filter layer. A color cathode ray tube having a maximum absorption in a predetermined wavelength band other than the range of ± 20 nm and complementing the light absorption of the color filter. 2. An envelope having a face plate having an outer surface and an inner surface, a funnel joined to the face plate and having a neck, and an envelope provided on the inner surface of the face plate and having a predetermined shape. A phosphor screen having phosphor layers of three colors of red, green, and blue arranged in a pattern, an electron gun provided in the neck for irradiating the phosphor screen with an electron beam to emit light, The phosphor screen is provided between the inner surface of the face plate and the phosphor screen, and
A color filter layer having three color filters of colors corresponding to the respective color phosphor layers arranged facing the respective color phosphor layers, wherein each color filter emits light from the corresponding color phosphor layer. Of the maximum emission spectrum wavelength ± 20n
a color filter layer having a transmittance for light having a wavelength in the range of m higher than that for light having a wavelength of 400 to 650 nm and having a wavelength other than the above range; Provided opposite to the color filter layer and having maximum absorption in a predetermined wavelength band other than the range of ± 20 nm of the maximum emission spectrum wavelength of the phosphor layers of the three colors, and complements the light absorption of the color filter. A color cathode ray tube comprising: a correction unit. 3. The color filter has a transmittance of 70% or more for light having a wavelength of 400 to 500 nm and a wavelength of 600 to 700 nm, and 5 to 65% for light having a wavelength of 500 to 600 nm. The color cathode ray tube according to claim 1, wherein the color cathode ray tube has an average transmittance of 4. The color filter for each color has a wavelength of 400.
To 500 nm, and wavelengths of 600 to 700 nm
Has a transmittance of 70% or more for light of wavelength 5
The color cathode ray tube according to claim 2, which has an average transmittance of 5 to 65% for light of 00 to 600 nm. 5. The phosphor screen includes a red phosphor layer, the color filter is provided to face the red phosphor layer, and has a transmittance of 70% or more for light near a wavelength of 627 nm. The color cathode ray tube according to any one of claims 1 to 4, further comprising: 6. The color cathode ray tube according to claim 1, wherein the correcting means includes an outer surface filter formed on the outer surface of the face plate and common to each color. . 7. The color cathode ray tube according to claim 1, wherein the face plate is made of neodymium glass and constitutes the correcting means. 8. The face plate according to claim 1, wherein the face plate has a substantially rectangular shape and has a wall thickness that increases from a center of the face plate toward a peripheral portion thereof at a predetermined rate of change. 2. The color cathode ray tube according to item 1. 9. The correcting means has a maximum absorption in the vicinity of a wavelength of 575 nm and has a wavelength of 50 to 9 with respect to the wavelength of the maximum absorption.
The color cathode ray tube according to any one of claims 1 to 8, which has a transmittance of 0%.