JPH0139182B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cathode ray tube device, particularly a cathode ray tube device suitable for application to, for example, a high brightness cathode ray tube used in a color projector. In high-brightness cathode ray tubes, the energy of the electron beam that impacts the fluorescent surface is increased to obtain a reproduced optical image with high brightness. In addition to this, for example, when providing an electrode for determining the electron beam arrival position such as a shadow mask or aperture grill for regulating the landing position of the electron beam with respect to the fluorescent surface within the tube facing the fluorescent surface, this is necessary. The heat generated by the impact of the electron beam on the electrode becomes more significant as the energy of the electron beam increases. However, since the front panel of the cathode ray tube body on which the fluorescent surface is formed, ie, the glass panel, has low thermal conductivity, the temperature rises significantly at the center of the front panel, where heat is difficult to dissipate, especially during continuous operation. Therefore, so-called temperature quenching occurs in the phosphor. This temperature quenching is a phenomenon in which the brightness of a phosphor decreases as the temperature rises, and since the degree of temperature quenching differs for each color's phosphor surface, it causes an imbalance in the white balance. Since any deviation in white balance at the center will significantly impede image quality, it may be possible to adjust the brightness of the optical image of each color so that the white balance can be maintained at this center during continuous operation. The disadvantage is that the balance is disrupted and the overall brightness cannot be increased. This applies, for example, when a color image is obtained by combining and projecting each color image obtained from each monochrome cathode ray tube onto a screen in a color projector, or when a color image made up of multiple color images is projected onto the same cathode ray tube. This is a problem in both methods of obtaining images and projecting them onto a screen. Therefore, in this type of high-brightness cathode ray tube, even during continuous operation, it is necessary to cool the front panel in order to prevent the temperature rise that would cause temperature quenching on the fluorescent surface. . This cooling may be done by a cooling fan, but in this case, dust is sent to the front panel surface of the tube along with air, and this dust adheres to the panel surface, causing the apparent brightness to decrease. cause deterioration. In this case, there also arises the problem of noise from the cooling fan. In order to avoid these drawbacks, it has been proposed to cool the cathode ray tube by disposing a transparent liquid cooling medium, especially a liquid that is susceptible to convection, in contact with the front panel of the cathode ray tube. Such a liquid-cooled cathode ray tube device, particularly a closed convection type cathode ray tube device, has, for example, a structure in front of the front panel of the cathode ray tube 1, as shown in a partially sectional side view of FIG. A light-transmissive transparent panel 2 made of glass is surrounded by a ring-shaped metal frame 3 with excellent thermal conductivity around both panels 1a and 2.
With this metal frame 3, the panel 1a is
and are arranged opposite to each other with a set interval between the two.
The metal frame 3 and the outer surface of the panel 1a and the inner surface of the panel 2 are bonded with a resin adhesive 4 and are sealed liquid-tight to form a liquid-tight space 5 between the panels 2 and 1a. The liquid-tight space 5 is filled with a transparent liquid refrigerant 6 that easily causes convection. The cathode ray tube body 1 having such a structure is operated with its panel 1a being in a substantially vertical position. In this case, the cooling medium 6 filled in the closed space 5 is arranged thermally densely on the front panel 1a of the cathode ray tube body 1. Therefore, according to such a configuration, when a temperature rise occurs in the panel 1a, the heated cooling medium 6 moves upward, and this causes convection within the space 5. As a result, even if the heat is in the central part of the panel 1a, it is effectively transferred to the periphery, and the heat is transferred to the metal frame 3 made of aluminum, for example, which has excellent thermal conductivity and is arranged in the periphery. Heat is then transmitted through the metal frame 3 and dissipated from the outer periphery of the metal frame that comes into contact with the outside air. According to the cathode ray tube device having such a configuration, the temperature rise in the panel 1a can be suppressed relatively effectively. However, recently, for example, in projectors,
The cathode ray tube was required to have high brightness and high resolution.
As brightness increases, higher power is required, and more and more effective heat dissipation is required. Furthermore, with this increase in power (power P is given by P = Vp × Ik, where Vp is the anode voltage (acceleration voltage) and Ik is the cathode current), when the acceleration voltage is increased, The thickness of the front panel of the tube body 1 needs to be increased in order to avoid an increase in X-ray transmittance. However, in the projector,
Particularly when a plastic lens is used in the optical system, the distance between the fluorescent surface 7 and the lens, that is, the thickness of the front panel 1a, cannot be made too large due to lens design. Therefore, in this case, a method is adopted in which the content of, for example, lead, which has an X-ray shielding effect, is increased as the glass material of the transparent panel 2. However, the hardness of glass containing a large amount of lead decreases,
It becomes a tendency to be easily hurt. Therefore, in this case, if the temperature rise as described above occurs and the transparent panel 2 undergoes deformation such as deflection due to thermal expansion,
In particular, damage is likely to occur. Therefore, as brightness increases, more effective heat dissipation cooling is required. For this reason, for example, in the conventional structure shown in Fig. 1, the surface area in contact with the outside air is increased by, for example, providing heat dissipation fins, but even with this method, the heat dissipation is not much more effective. do not have. As a result of various experimental studies, the inventors of the present invention have determined that this is because the heat of the cooling medium 6 is not effectively transferred to the metal frame 3. That is, in reality, the metal frame 3 is such that both outer and inner surfaces of the portion interposed between the panels 2 and 1a are liquid-tightly bonded to the panels 2 and 1a by the resin 4. Furthermore, it has been found that the area of the metal frame 3 in contact with the cooling medium 6 is small, and therefore the heat of the cooling medium 6 is not effectively transferred to the metal frame 3. In the present invention, consideration has been given to effectively transmitting the heat of the cooling medium to the metal frame based on this investigation. An example of a cathode ray tube device according to the present invention, that is, a closed convection type liquid-cooled cathode ray tube device, will be described with reference to FIG. 2 and subsequent figures. In the present invention, as shown in FIG. 2, a metal frame 10 is arranged around the effective screen on the outer surface of the front panel 1a on which the fluorescent surface 7 of the cathode ray tube body 1 is formed. A transparent panel 11 such as a glass plate is opposed to the front panel 1a with a required distance therebetween to form a liquid-tight space 12 between the panels 11 and 1a.
0 has a special configuration that will be explained in detail later. The metal frame 10 is liquid-tightly adhered to the transparent panel 11 and the front panel 1a, respectively, by an adhesive resin 13 such as silicone resin, and the metal frame 10 and the transparent panel 11 are mechanically bonded to the panel 1a. A liquid cooling medium 23, such as an ethylene glycol aqueous solution, is injected and filled into the liquid-tight space 12 between the transparent panel 11 and the front panel 1a. The front view of the metal frame 10 is shown in FIG.
The side view is shown in Figure 5, and A-A of Figure 3 is shown in Figure 5.
As shown in the cross-sectional view along the line, the adhesive resin 13 is made of die-cast aluminum having excellent thermal conductivity, and is interposed in the peripheral area between the front panel 1a and the transparent panel 11 of the cathode ray tube body 1. A frame-shaped portion 10a that functions as a spacer to regulate the distance between the panel 1a and the panel 11 and has a contour shape corresponding to the contour shape of the front panel 1a of the cathode ray tube body; a ring-shaped peripheral wall portion 10b bent along the outer periphery of the peripheral surface portion _1a1 ;
Furthermore, there is a mounting screw hole 1 which is bent outward from the opposing sides, that is, in a direction substantially perpendicular to the tube axis, and is used for mounting the cathode ray tube 1 to a cabinet or the like.
4, and a plurality of heat dissipation fins 10d, which are erected in parallel in a direction orthogonal to the flange 10c, for example, in a portion having the flange 10c. In particular, in the present invention, a frame portion 10a that is interposed between the panel 11 and the front panel 1a to regulate the distance between the two, that is, a portion that is bonded to the panels 11 and 1a by the adhesive resin 13 is located on the inner side. To,
A plate-like protruding portion 10e having a wall thickness smaller than that of the frame portion 10a is made to protrude inwardly over substantially the entire inner circumference of the frame portion 10a. This protrusion 10e prevents the adhesive resin 13 from being adhered, and furthermore, by the presence of the thickness of the adhesive resin 13, or by making the protrusion 10e thin, Each surface facing the panels 11 and 1a is made to face the panels 11 and 1a with a gap therebetween, and most of the surfaces are immersed in the cooling medium 23, so that the protrusion 10e
most of the surface is in direct contact with the cooling medium 23. This protruding portion 10e is the frame portion 1
Although it is provided over almost the entire inner circumference of the projection 10a, in the illustrated example, the cutout 10f of the protrusion 10e is provided at a portion where the injection hole 15 for injecting the cooling medium 23 into the space 12 is provided. , protrusion 1
0e is provided so as to protrude from the entire inner periphery of the frame portion 10a except for this cutout portion 10f. Further, this metal frame 10 has a protrusion 10e extending outward from the effective screen position indicated by the symbol a in FIG.
exists, but even in this case,
The light from the fluorescent surface 7 hits the protrusion 1 of the metal frame 10, for example.
At least the surface of the protrusion 10e is blackened so that the light does not disturb the optical image by being reflected at 0e. This blackening treatment is actually performed on almost the entire surface of the metal frame 10, and the heat radiation and the cooling medium 2
It is desirable to absorb heat from 3 more effectively. Incidentally, when the metal frame 10 is made of aluminum, this blackening treatment can be performed by alumite treatment and, if necessary, by using a dye. In this case, if the surface is insulated by the blackening treatment, for example, the blackening treatment surface is removed in a portion that does not affect the observation of the protrusion 10e or the optical image, and the cooling medium is applied here. and the metal frame are electrically connected. That is, as described above, the transparent liquid cooling medium 23 such as glycol
has a certain degree of electrical conductivity, so by electrically connecting the cooling medium 23 and the metal frame 10, the panels 11 and 1a can be connected via the cooling medium 23 and the metal frame 10, respectively. For example, the panels 11 and 1a can be grounded, and the effect of preventing static electricity on the panels 11 and 1a can be obtained. Further, as the adhesive resin 13, for example, a black silicone resin containing a black pigment is used. Furthermore, if necessary, this silicone resin may have a required thickness that functions as a spacer itself to regulate the distance between the panel 11 and the front panel 1a, working together with the frame portion 10e of the metal frame 10 to obtain the spacer effect. In order to ensure this, it is also possible to mix already hardened granular or ring-shaped elastic resin particles with a required thickness into the adhesive resin 13. According to the above-described configuration of the present invention, the heat dissipation effect is
It was confirmed that it was possible to increase the power of the cathode ray tube by 30% over that of conventional closed convection liquid-cooled cathode ray tube devices and still maintain the current reliability. . That is, looking at the temperature rise on the surface of the cathode ray tube with respect to the cathode current Ik when the anode voltage Vp applied to the fluorescent surface 7 is selected to be 27 kV, in the present invention, as shown in curve 16 in FIG. Become. Compared to this, the first
In the conventional structure explained in the figure, namely,
When the metal frame is not provided with a protrusion that is immersed in the cooling medium, it becomes as shown in curve 17. At the same cathode current, that is, at the same power, the temperature rise according to the present invention is lower than that of the conventional method. It can be seen that since the temperature can be kept low, the power can be further improved in a state where the temperature is allowed to be the same as in the conventional case. Table 1 also shows examples of cathode ray tube devices with the conventional structure explained in FIG. 1 (Comparative Examples 1, 2, and 3).
and Vp=26kV, Ik= for each example (Examples 1, 2, 3, and 4) of the cathode ray tube device according to the present invention, respectively.
The results of measuring the average temperature of the cooling medium when operating continuously at 430 μA and when the temperature reaches an equilibrium state are shown. In this case, the heat dissipation area in contact with the outside air and the heat absorption area in contact with the liquid refrigerant in each example are shown relative to that in Comparative Example 1 as 1, and in Examples 1 to 4, metal The thickness of the frame portion 10a of the frame 10 is 3.8 mm, and the protruding portion 1
When the thickness of the protrusion 10e is 1 mm, in Examples 1 and 2, the protrusion width of the protrusion 10e is 3 mm, and in Examples 3 and 4.
This is when the diameter is 5 mm.

【table】

[Table] As is clear from this table, in the case of the present invention, the heat radiation effect increases as the heat radiation area increases, and the temperature rise of the cooling medium is suppressed. As described above, according to the configuration of the present invention, the metal frame 10 interposed between the transparent panel 11 and the front panel 1a of the cathode ray tube body 1 is provided with the protrusion 10e that contacts the liquid refrigerant, and this is made thin. Since the entire surface of the thin protrusion 10e, that is, both the front and back surfaces, can be immersed in the cooling medium 23, the protrusion 1
0e, therefore, it is possible to expand the contact area of the metal frame 10 with the cooling medium 23, thereby significantly increasing the heat dissipation effect, and thereby increasing the power of the cathode ray tube. It is possible,
Higher brightness cathode ray tubes can be obtained. In particular, as mentioned above, in a color projector, the occurrence of temperature quenching can be avoided by suppressing the temperature rise, and a reproduced image with bright color and high color purity without any deviation in white balance can be obtained. Furthermore, as described above, by immersing the protrusion 10e in the liquid cooling medium 23 to enhance its heat dissipation effect, the protrusion area of the protrusion 10e can be reduced, and the ineffective area of the screen can be reduced. The cathode ray tube device has the great practical effect of being able to be downsized, and thus the entire cathode ray tube device can be downsized. Further, the metal frame 10 is subjected to a blackening treatment, and in particular, the blackening treatment is applied to at least the side of the protrusion that protrudes as if immersed in the liquid refrigerant and is observed from the front, thereby improving the contrast and This effectively avoids deterioration in image quality due to unnecessary reflection of light.

[Brief explanation of drawings]

Fig. 1 is a partially sectional side view of a conventional closed convection type liquid-cooled cathode ray tube device, Fig. 2 is a sectional view of an example of a cathode ray tube device according to the present invention, and Fig. 3 is a metal frame thereof. Figure 4 is its front view, Figure 4 is its side view, and Figure 5 is its side view.
The figure is a sectional view taken along line A--A in FIG. 3, and FIG. 6 is a temperature characteristic curve diagram. 1 is a cathode ray tube body, 1a is its front panel, 7
1 is a fluorescent surface, 11 is a transparent panel, 10 is a metal frame, 1
0e is its protrusion, and 23 is a liquid cooling medium.

Claims (1)

[Claims] 1. A metal frame is arranged around the effective screen on the outer surface of the front panel of the cathode ray tube body, and a transparent panel is inserted through the metal frame at a distance defined by the metal frame with respect to the front panel. A liquid-tight space is formed between the front panel and the transparent panel facing each other, a transparent liquid cooling medium is sealed in the liquid-tight space, and a liquid-tight space between the transparent panel and the front panel is sealed. A protruding portion having a wall thickness thinner than a wall thickness of the metal frame that is immersed in the liquid cooling medium and comes into contact with the liquid cooling medium over the entire surface is provided on the inner circumferential end of the metal frame facing the metal body frame. A cathode ray tube device that is integrated.