JPH0765753A - Projection cathode-ray tube and projection image device - Google Patents

Abstract

PURPOSE:To provide a projection cathode-ray tube and a projection image device using the same, having an excellent color tone of green, a bright projection image, and excellent cost performance, and moreover, easiness in mass- production. CONSTITUTION:A filter MIF made of an optical interference film is formed at either surface of a glass plate PLT having approximately the same size as a face plate panel PNL. A surface of the glass plate PLT where the filter MIF is not formed is disposed on a side of the face plate panel PNL. The surface of the glass plate PLT where the filter MIF is formed is formed into a recess, the center of which is curved toward the face plate panel PNL.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type cathode ray tube, and more particularly, to a projection type cathode ray tube which has a better green color tone, brighter projected image, and is easily mass-produced and has an excellent price / performance ratio. The present invention relates to a projection type image device using the same.

[0002]

2. Description of the Related Art A projection-type cathode ray tube magnifies and projects an image displayed on its fluorescent surface on a projection screen arranged at a predetermined distance determined by the magnification and projection optical system (lens system). It is used in a projection-type image device for displaying as.

A projection type image device using such a projection type cathode ray tube directly displays a color image such as a television broadcast reproduced and displayed on a face plate panel surface of a color cathode ray tube which has been conventionally used at home. Larger screen size (especially so-called 40-inch or larger) than the direct-viewing type video device
It was commercialized as a means for viewing television images, etc., and in recent years it has begun to be widely used due to its improved performance.

However, in order to endure normal indoor viewing during the daytime, the image displayed on the face plate panel surface of the projection type cathode ray tube is of a direct-view type because of the structure of the projection type image device. Clearly, it must be much brighter and more detailed than it should be. Also, in order to make it extremely bright, the fluorescent surface is scanned by an electron beam with a high current density, so even if the natural circulation liquid cooling system is adopted, the temperature of the fluorescent surface rises remarkably. A phosphor different from the case of the color cathode ray tube must be used, and the color tone of the green light emitting phosphor and the red light emitting phosphor is not good.

Various attempts have been made to solve the above-mentioned problems of the projection type cathode ray tube. For example, as shown in FIG. 8, the inner surface of the face plate panel PNL and the phosphor film PH are formed. A multi-layer optical interference film (incident angle sensitive type) filter MIF is formed between them, and as shown in the enlarged view of the vicinity of the fluorescent film in FIG. 9, among the light rays LGT emitted from the phosphor particles ph, the filter MIF is included. Only a light ray (incident light path from the fluorescent body is short and relatively bright) LGT that is incident at an incident angle with respect to a certain value or less passes through the filter MIF and is emitted from the face plate panel PNL. Japanese Patent Application Laid-Open No. 55-150532 discloses a proposal for making an incident light beam (the optical path from the fluorescent body is long and relatively dark) almost totally reflected.

When the projection distance is made as short as possible and the angle of view is widened as in a rear projection type television, the fluorescent surface formed on the inner surface of the face plate is not flat as in the case of a direct-view tube. , The image around the projection screen is blurred, so-called field curvature increases and the screen peripheral brightness decreases, and when the incident angle sensitive filter is provided, the light output becomes a directional distribution and the screen peripheral brightness becomes disadvantageous. Therefore, as shown in FIG. 8, the center portion of the inner surface of the face plate panel PNL is curved so as to approach the electron gun side, and the optical axis of the peripheral portion of the fluorescent surface is tilted toward the pupil (center portion) of the projection lens. There is.

As described above, if the filter MIF made of a multilayer optical interference film is provided immediately before the fluorescent surface, the light ray LGT having a large incident angle that causes a halo without such a filter is almost totally reflected. In addition to suppressing the halo, the light output taken in by the projection lens arranged in front of the face plate panel PNL is increased, the brightness on the projection screen is improved by 40 to 60%, and the wavelength of the filter MIF is further increased. Due to the (color) selection effect, the green and red tones described above are also improved.

[0008]

However, in the projection type cathode ray tube according to the above-mentioned conventional technique, the diameter of the beam spot formed on the outer surface of the face plate may be large, and the focus (resolution) is deteriorated by 10 to 20%. . Furthermore, as a fatal defect for the projection type cathode ray tube which is a mass-produced product,
When a filter MIF made of a multilayer optical interference film is formed by vapor deposition, the presence of a panel skirt that is bent in the funnel direction at the edge of the face plate affects the gas flow path at the edge of the vapor deposition material, which is a great obstacle to the formation of a good filter film. In addition, the filter must be formed by the face plate alone, and after the formation, the face plate panel must be welded to the funnel with a low temperature glass frit FRT or the like.
Compared with the projection type cathode ray tube without the filter used in the past, the manufacturing process was complicated and the price increased.

Further, recently, a lens colored with an organic dye or a lens having an optical interference filter (dichroic filter) is used as a part of the lens of the projection lens system so that light from each monochromatic cathode ray tube is 2. Description of the Related Art A projection-type cathode ray tube in which a color of an unnecessary region is cut to improve a color tone and a projection-type image device using the projection-type cathode-ray tube are generally put into practical use.

However, in the projection type cathode ray tube using the above lens, the brightness (luminance) on the screen of the projection type image device is used in order to simply cut the color of the unnecessary area of the light from the cathode ray tube by the filter. Is reduced by 10 to 30%. This is a serious problem especially for large screen projection type image devices of 50-inch or larger size.

The object of the present invention is to eliminate various problems that have occurred in the above-mentioned conventional projection type cathode ray tube and the projection type image device using the same, and the color tone, particularly the green color tone, is better than that of the direct-view type color cathode ray tube. Therefore, it is an object of the present invention to provide a projection type cathode ray tube which is considerably brighter than a conventional device and which can be easily mass-produced and has an excellent price / performance ratio, and a projection type imaging device using the same.

[0012]

In order to achieve the above object, in the present invention, a filter composed of a multilayer optical interference film is formed on one side of a glass plate having a size substantially the same as that of a face plate panel, and the glass plate filter is used. The surface on the side not formed is disposed on the outer surface side of the face plate panel, and in particular, the transmittance of the filter provided in the green image projection cathode ray tube is 85% in the wavelength range of 530 to 560 nm. As described above, it is set to 30% or less in the region of 500 nm or less and 580 nm or more, and the filter of the glass plate is formed when further improvement in brightness is desired (lens system side).
The surface is formed into a concave surface curved toward the face plate panel side with a radius of curvature of 300 to 1000 mm according to the size of the image to be projected on the screen, and the glass plate is made of a material in vacuum for Na-D lines. Alternatively, a material having a refractive index in air of 1.45 to 1.55 is used.

[0013]

In the projection type cathode ray tube according to the present invention, the light rays emitted from the phosphor film formed on the inner surface of the face plate panel are transmitted through the face plate panel and then the glass provided outside the face plate panel. The light passes through the plate and enters the filter formed of the multilayer optical interference film formed on the concave surface on the lens system side. At that time, a light ray incident at a larger incident angle than a predetermined value is almost totally reflected and cut,
Only light rays incident at a small angle of incidence below the above specified value,
The light is transmitted through the filter film and emitted while undergoing a wavelength range selection operation determined by the filter film thickness. The light rays that have passed through the filter film formed on the concave surface are efficiently collected by the magnifying projection lens system arranged in front of the face plate panel, and bright, good color tone and magnified projection image is obtained on the projection screen. You can

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As can be seen from the front view of the main part of a projection type image device, the faces of a projection type cathode ray tube rPRT for red image, a projection type cathode ray tube gPRT for green image and a projection type cathode ray tube bPRT for blue image are seen. The red, green, and blue monochromatic images reproduced and displayed on the plate panel PNL are respectively condensed and enlarged by the magnifying projection lens system LNS, and the three primary color images are projected and superimposed on the projection screen to be combined and color-coded. The image can be obtained. It is unavoidable that a large projection screen surface is required for the projection type image device as a whole, but in order to make it as compact as possible, for example, as shown in the side view of FIG. 2, a mirror is arranged in the middle of the optical path for projection. The depth of the set is reduced by adopting a structure in which the image is reflected on the back surface, and three monochromatic projection type cathode ray tubes PRT are arranged in a direction perpendicular to the paper surface of this figure. As shown in FIG. 2, the projection cathode ray tube PRT has a projection lens system LNS coupled through a coupler CPL,
It is located below the video device set. The coupler CPL shown in FIG. 2 has a structure that can withstand changes in size and volume of each component due to temperature changes, and has a cooling liquid hermetically contained between the outer surface of the face plate panel and the lens closest to the face plate. Is.

FIG. 3 is a cross-sectional view showing the main part near the face plate panel of the first embodiment of the present invention. In the figure, MIF is a filter using a multilayer optical interference film, PLT is a glass plate on which the filter is formed (the side on which the filter is formed is a concave surface), PH is a fluorescent film, and MBK is a fluorescent film. , A metal back film that prevents the negative charges from accumulating on the fluorescent surface due to electron beam bombardment and reflects the light emission of the fluorescent material to the front side to increase the brightness of the display screen.
ND is a band that presses the outer surface of the panel skirt to prevent implosion, ACP is an anode cap that connects the electrode of the power supply line for supplying the anode potential to the fluorescent film from the outside, and FNL is a vacuum envelope. It is a funnel of a glass bulb.

The thin line at the boundary between the funnel FNL and the face plate panel PNL is the connection between the face plate panel and the funnel formed by the mold, but in the case of the projection type cathode ray tube according to the present invention. As in the case of the projection type cathode ray tube of the type without a filter previously, the connection work of this part is completed at the factory of the glass bulb manufacturer, and the cathode ray tube manufacturer has to do the work such as welding with low temperature frit glass. Is unnecessary.

In the projection type cathode ray tube according to the present invention, Y ₂ O ₃ : Eu is used for the red light emitting phosphor, and Y ₃ (Al.Ga) ₅ O ₁₂ : Tb is used for the green light emitting phosphor. ZnS: Ag.Al is used for the blue light emitting phosphor. The optical interference film filters for red, green, and blue having the optical characteristics (spectral transmission characteristics) shown in FIGS. 4A, 4B, and 4C corresponding to them are provided on the glass plate PLT. It is formed on the outer side (lens system side) forming a concave surface. In particular, the spectral transmittance of the filter corresponding to the green arc tube is 85% or more in the wavelength range of 530 to 560 nm, and 500 nm or less (blue range).
In the region of 0 nm or more (red region), it is 30% or less, and a good green color tone can be obtained.

A glass plate on which a filter MIF is formed (a refractive index of 1.45 to 1.55 with respect to Na-D line in vacuum or in air as described above) is used as a face plate panel PNL of a cathode ray tube. It is optimal to use an adhesive such as a silicone resin for fixing and fixing.

FIG. 5 is a cross-sectional view showing the main part near the face plate panel of the second embodiment of the present invention. In this embodiment,
Glass plate PL with a multilayer optical interference film MIF fixed to the outer surface side of a face plate panel PNL of a projection type cathode ray tube
The manufacturing process is simplified by using T as a flat plate.

FIG. 6 is a cross-sectional view showing the main part near the face plate panel of the third embodiment of the present invention. In this embodiment,
A glass plate PLT with a multilayer optical interference film MIF is fixed to the outer surface side of the face plate panel PNL of the projection type cathode ray tube via a spacer SPC. Then, for example, the liquid coolant CLM is injected between the face plate panel PNL and the glass plate PLT, and the optical coupling between them is further improved.

In the method of using a lens colored with an organic dye or the like or a lens having an optical interference filter (dichroic filter) formed on a part of the lenses of the lens system as described above, light is absorbed by the lens system and the brightness is increased. However, it was confirmed by experimental trial evaluation that the brightness was improved by about 10% in the example of the present invention. The reason is that the directivity to the center of the lens system due to interference and multiple reflections contributes to the increase in the directivity toward the center of the lens system due to interference and multiple reflections, as in the case where a filter is formed on the inner surface of the face plate panel between the phosphor film and the fluorescent film. This is because It was also confirmed that the resolution (focus) did not decrease.

Further, in the present invention, the front side (lens system side) of the glass plate attached to the outer surface of the face plate panel of the projection type cathode ray tube and having the filter MIF formed by the multilayer optical interference film is directed to the face plate panel side. Since it is formed in a curved concave surface, the light converging property for the lens system is improved.

Further, when the multilayer optical interference film forming the filter is formed by the vapor deposition method, when the filter made of the multilayer optical interference film is formed on the inner surface side of the face plate panel as described above, the central portion is the vapor deposition source side. It is difficult to form a filter with a good light-collecting property in the peripheral part, because the panel skirt part is close to the
In the present invention, it is possible to easily form the film thickness of the peripheral portion slightly thicker than the central portion so that the light condensing property in the peripheral portion is better than that in the central part, so that the light condensing property is further improved, and The color uniformity of the peripheral portion can be improved.

Further, by using a glass plate made of a material having a refractive index (1.45 to 1.55) substantially equal to the refractive index (1.52 to 1.55) of the face plate panel of the projection type cathode ray tube, Improve the optical coupling of the projection type cathode ray tube with the face plate panel, and make the refraction angle at the coupling surface smaller than the incident angle to refract in the center direction of the lens system to improve the light converging property. Is considered.

In the above embodiment, a filter having a multilayer optical interference film is formed on the front surface side (lens system side) of the glass plate, or on the front surface side (lens system side) of the glass plate.
However, the present invention is not limited to these, the filter may be formed on the rear surface side of the glass plate (face plate panel side), and the glass plate Even if the rear surface side (face plate panel side) is formed as a convex surface, the light condensing property of the peripheral portion is improved.

FIG. 7 shows CIE chromaticity coordinates comparing the color tones of various conventional projection type cathode ray tubes and the projection type cathode ray tube according to the present invention. The color tone increases as the direction of the arrow in the figure increases, and the larger the triangle shown in the figure, the wider the color reproduction range (the better). The projection type cathode ray tube according to the present invention is slightly inferior to the projection type cathode ray tube provided with the multilayer optical interference film filter on the inner surface of the panel, and the conventional projection type cathode ray tube, the projection type cathode ray tube using the colored lens, and the direct view. It can be seen that the color tone is better than that of the cathode ray tube. As for the brightness (luminance), as shown in Table 1, the projection type cathode ray tube according to the present invention is superior to the conventional projection type cathode ray tube and the projection type cathode ray tube using the colored lens.

[0027]

[Table 1]

[0028]

As described above, according to the present invention, a projection type cathode ray tube which has a better color tone such as green, a brighter projected image, and can be easily mass-produced and which has an excellent price / performance ratio as compared with the prior art. There is an effect that a projection type image device using the same can be obtained.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a projection type video device.

FIG. 2 is a side view of a projection type image device in which a mirror is arranged in the middle of the optical path to reduce the depth dimension of the set.

FIG. 3 is a cross-sectional view showing a main part near a face plate panel according to the first embodiment of the present invention.

FIG. 4A is a diagram showing spectral transmission characteristics of an optical interference film filter used in a red projection type cathode ray tube according to the present invention,
(B) is a diagram showing the spectral transmission characteristics of the optical interference film filter used in the green projection cathode ray tube according to the present invention, and (c) is the spectrum of the optical interference film filter used in the blue projection cathode ray tube according to the present invention. It is a figure which shows a transmission characteristic.

FIG. 5 is a sectional view showing an essential part near a face plate panel according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing an essential part near a face plate panel according to a third embodiment of the present invention.

FIG. 7 is a C comparing the color tones of various projection type cathode ray tubes of the related art or a normal direct-view type cathode ray tube and the projection type cathode ray tube of the present invention.
It is a figure which shows IE chromaticity coordinate.

FIG. 8 is an enlarged cross-sectional view in the vicinity of a face plate panel of a conventional projection cathode ray tube in which a filter (incident angle sensitive type) made of a multilayer optical interference film is formed between the inner surface of the face plate panel and the phosphor film. Is.

FIG. 9 is a diagram for explaining the effect of the filter in the conventional projection type cathode ray tube in which the filter made of the multilayer optical interference film is provided between the inner surface of the face plate panel and the phosphor film.

[Explanation of symbols]

 rPRT ... Projection type cathode ray tube for red image gPRT ... Projection type cathode ray tube for green image bPRT ... Projection type cathode ray tube for blue image PNL ... Face plate panel LNS ... Projection lens system PH ... Fluorescent film MIF ... From multilayer optical interference film Filter PLT ... Glass plate SPC ... Spacer CLM ... Liquid refrigerant

Claims (4)

[Claims] 1. A projection type cathode ray tube characterized in that a filter made of an optical interference film is formed on a glass plate having substantially the same size as a face plate panel, and the glass plate is disposed on the outer surface side of the face plate panel. 2. A filter made of an optical interference film is formed on one surface of a glass plate having substantially the same size as the face plate panel, and the surface of the glass plate on which the filter is not formed is disposed on the outer surface side of the face plate panel. A projection-type cathode ray tube characterized in that 3. The transmittance of a filter provided in a green image projection cathode ray tube is 85% or more in a wavelength range of 530 to 560 nm, and 30% or less in a wavelength range of 500 nm or less and 580 nm or more. The projection type cathode ray tube according to claim 1. 4. A projection type image device for condensing and enlarging an image reproduced and displayed on a face plate panel of a projection type cathode ray tube by a magnifying projection lens system and projecting the image onto a projection screen, wherein a filter made of an optical interference film is used. A projection type video device, comprising a projection type cathode ray tube, which is formed on a glass plate having substantially the same size as a face plate panel, and the glass plate is disposed on the outer surface side of the face plate panel.