CA1205509A - Cathode ray tube apparatus - Google Patents
Cathode ray tube apparatusInfo
- Publication number
- CA1205509A CA1205509A CA000429864A CA429864A CA1205509A CA 1205509 A CA1205509 A CA 1205509A CA 000429864 A CA000429864 A CA 000429864A CA 429864 A CA429864 A CA 429864A CA 1205509 A CA1205509 A CA 1205509A
- Authority
- CA
- Canada
- Prior art keywords
- ray tube
- cathode ray
- heat radiator
- panel
- front panel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/006—Arrangements for eliminating unwanted temperature effects
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J31/00—Cathode ray tubes; Electron beam tubes
- H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
- H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
- H01J7/24—Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space
Landscapes
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
- Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
- Electrodes For Cathode-Ray Tubes (AREA)
- Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A liquid cooled cathode ray tube is disclosed which includes a cathode ray tube with a planar front panel coated with a phosphor screen, a metal heat radiator and spacer surrounding the planar front panel, a planar transparent panel supported by the metal heat radiator, a spaced distance from the planar front panel, sealant on the planar surfaces and sealing the heat radiator to the planar front panel and the planar transparent panel to form a closed sealed liquid retaining chamber, and transparent coolant filling the sealed liquid retaining chamber, the heat radiator having a fin extending inwardly from the inner wall thereof.
A liquid cooled cathode ray tube is disclosed which includes a cathode ray tube with a planar front panel coated with a phosphor screen, a metal heat radiator and spacer surrounding the planar front panel, a planar transparent panel supported by the metal heat radiator, a spaced distance from the planar front panel, sealant on the planar surfaces and sealing the heat radiator to the planar front panel and the planar transparent panel to form a closed sealed liquid retaining chamber, and transparent coolant filling the sealed liquid retaining chamber, the heat radiator having a fin extending inwardly from the inner wall thereof.
Description
~Z,~;)5509 BACKGROUND OF THE INVENTION
Field of the Invention This invention relates generally to a cathode ray tube apparatus and more particulaxly is directed to a cathode ray tube apparatus suitable for a high-brightness cathode ray tube used in, for example, color projectors.
Description of the Prior Art The high-brightness cathode ray tube is generally arranged such that the energy of an electron beam to impinge on its phosphor screen is increased to generate a reproduced optical image of high brightness. In this case, the heat generated by the impingement of the electron beam on the phosphor screen or in addition thereto, the heat generated by the impingement of electron beams on an electron beam landing position determining electrode such as a shadow mask, an aperture grille or the like which is provided within the tube envelope so as to oppose the phosphor screen for restricting the landing position of the electron beam on the phosphor screen becomes more conspicuous due to the increase of the energy of the electron beam. However, since the front panel or the glass panel of the tube envelope of the cathode ray tube on which the phosphor screen is formed has a low thermal conductivity, particularly in the continuous use, a significant rise of temperature occurs in the center of the front panel where it is difficult to radiate heat, thus causing a so-called thermal quenching in the phosphor. The thermal quenching is a phenomenon which causes the brightness of the phosphor to be lowered as the temperature increases.
O5~iO~
Since the degree of the thermal quenching is different depending on the phosphor of each color, the white balance is disturbed.
Since the disturbed white balance at the center of the front panel considarably degrades the picture quality, it may be considered to adjust the brightness of an optical image of each color so as to achieve the correct white balance at the center of the front panel during the continuous use. In this case, the white balance at the ., peripheries of the front panel is disturbed and also an overall brightness can not be increased.
This defect also appears in, for example, a color projector in either case where images of respective colors produced from respective monochromatic cathode ray tubes lS are mixed and projected onto a screen so as to obtain a color picture image or a color image formed of images of plural colors is obtained by the same cathode ray tube and then projected onto the screen.
In the high brightness cathode ray tube of this kind, in order to avoid the rise of temperature due to the continuous use which may cause the thermal quenching on the phosphor screen, it is necessary to cool the front panel.
The cooling of the front panel may be performed by a cooling fan. In this case, if such cooling operation is performed, a wind is blown to the front panel surface of the tube envelope and at the same time, dust is supplied to the panel surface. Such dust adheres to the panel surface to cause the brightness to be deteriorated apparently. Also, in this ~ case, the cooling fan may also cause noise.
In order to obviate such defects, a cathode ray ~3~
tube apparatus has been proposed in which a tr~nsparent liquid ~oolant or parti~ularly ~ liquid ccolant which easily causes a convection is located in contact with ~he front panel of the tube envelope of the cathode ray tube ~o as to cool the front p~nel.
BRIEF DESCRIPTION OF THE DR~WINt:S
~.
Fig. 1 is a partially cross~sectional side ~iew of a prior art liquid cooled cathode ray tube apparatus of closed-convection type;
lo Fig. 2 is a cross-sectional view of an embodiment of a cathode ray tube apparatus according to this invention;
. Fig. 3 is a front view of a metal Erame thereof;
Fig. 4 is a side view th.ereof;
Fig. 5 is a cros~-sectional view taken alsng the line A-A in Fig. 3; and Fig. 6 i~ a graph indicating temperature charac-t ristics on the ~urfac~ o~ the cathode ray tube envelope.
Fig. 1 i~ a partially cross-sectional side view of such previously propoæed liquid-cooling type ca~hode ray ~ube apparatu~ particularly a closed convec.tion type ~athode ray tube apparatus. As, for example r shown in ~ig. 1, fiuch cathode ray tube apparatus comprises a cathode r~y tube envelope 1 having a front panel la. A transparent panel 2 made of, for example, glass and having an optical transmis-~ivity is provided in front of the front panel la, and an annular metal frame 3 having an excellent thermal conduc-tivity is interposed between both ~he panel~ la and 2 along their peripheries wherein the metal frame 3 determines the .
spacing between the panels la and 2 and opposes them to each other. The peripheral portions of the metal frame 3, the outer surface of the panel la and the inner surface of the panel 2 are bonded together by resin adhesive agent 4 and sealed in liquid-tight to form a liquid-tight space 5 between the panels 2 and la. Transparent liquid coolant 6 which ea~ily causes a convection is fîlled into this li~uid-tight space 5. In Fig. 1, 7 designates -a~ phosphor screen formed on the inner surface of the panel la.
The cathode ray tube envelope 1 having such configuration is used under the state that the panel la is made substantially vertical.
In thi~ case, the liquid coolant 6 filled into the liquid-tight space 5 closely contacts with the front panel la of the cathode ray tube envelope 1 thexmally.
Therefore, according to such configuration of the conven-tio~al cathode ray tube appaxatus, when the rise of temperature occurs in the panel la, the liquid coolant 6 heated thereby moves upwards to cause the convection in the liquid-tight space 5. Thu~, even heat at, for example, the central portion of the panel la i5 effecti~ely moved to the peripheral portion thereof. This heat is then conducted to the metal frame 3 made of metal having 3 good heat con-ductivity, for example, aluminium which is pro~ided in the peripheries thereof with the result that the heat is conducted through the metal rame 3 and then radiated from the external peripheral poxtion o~ the metal ~rame 3 contacting with the . -5-~2~
open air.
- According ~ the cath~de ray tube apparatus thus arranged, it is possible to suppress the rise of temperature in the panel la relatively eiEfectively.
However, recently, the pro~ector has been requested to have high brightness and hi~h resolution of its cathod~
rsy tube and als~ requested to have a great power associated with high brightness, which then requires more and more eEfective heat radiation. Furthermore, when its accelerating voltage is increased in accordance with the pro~eckor having greater power ~power P is given by the equation expressed as P - Vp x Ik where Vp is the an~de voltage ~accelerating voltage) and Ik is the cathode current), the thic~ness of the ~ront panel la of the tube envelope 1 must be increased in order ~o avoid the increase of the X-ra~ transmission.
~owever, when the pro~ector employs particularly a plastic lens as its optical sy~tem~ a di~tance between the phosphor screen 7 and the lens, or ~he thickness of the ~ront pan~l la can not be increa~ed too much in view of the designing of the lens. Therefore, in this case, for a glass material of the transparent panel 2, it has been proposed to increase, fcr example, the lead content which has the shielding effect of X-ray. The glass containing a large amount of lead as described above is lowered in its hardness and is easily scratched. So, in this case, if the rise ~ temper-ature occurs as described before t~ cause the deformation such as bending due to thermal expansion in the txansparent panel 2, the transparent panel 2 may easily be broken.
~1l2~
Therefore, the higher brightness needs the more effective cooling by heat radiation.
For ~his reason, in the prior art ca~hode ray tube apparatus 9f the configuration as, for example, ~hown in Fig. l, for example, a heat radiation fin is provided to increase ~he surface area by which the metal frame 3 contacts with the air. ~owever, if it is done so, the heat radiation is not performed so effectively. As a result of various experiments and researches r the inventors of the present invention found out that the reason for that was that the heat of the li~uid coolant 6 was not ~ffectively conducted ~o thP metal frame 3. Namely, ~ince in practice the metal frame 3 was bonded in liquid-tight by the resin 4 to the panels 2 and la outside and inside surfaces of the portion int~rposed between both the panels 2 and la, the ~rea in which the metal frame 3 c~ntacts with the liquid coolant 6 was small and hence the heat of the liquid coolant 6 was not effectively conducted to ~he metal frame 3.
OBJECTS AND S~MMARY OF THE INVENTION
Accordingly, it is an ob~ect of this invention to provide a cathode ray tube apparatus capable vf obviating the afore-said defects inherent in the conventional cathode ray tube apparatus. :
Another object of this invention is to provide a cathode ray tube apparatus of high brightness which is free from a so-called thermal quenching.
Still another ob~ect of this invention is to provide a cathode ray tube apparatus of high brightness having a cathode ray tube capable of offering a high power 3 o and a high resolution.
iS~9 ~urther object o~ thi~ invention is to provide a cathode ray tube apparatus of high brightness which can perform more effeckive heat radiation and liquid cooling operations.
Still further ob~ect of this invention is to pr~vide a cathod~ ray tube apparatus of high brightness which can effectivel~ conduct heat of liquid coolant to a metal ~rame surrounding an effective picture screen.
Yet fur~h2r object of this invention is to provide a cathode ray tube apparatus suitable, ~or a cathode ray tube of high brightness employ~d for color projectors.
According to an aspect of this invention, *here i~ provided a liquid cooled cathode ray tube comprising a cathode ray tube'with a planar front panel coated with a phosphor screen, a metal heat radiator and ~pacer surrounding ~iaid planar ront pan~l, a planar transpaxent panel supported by said metal heat radiator,a spa~ed distance from said planar front panel, ~ealant on said planar suraces and sealing said heat radiator to said planar front panel and said planar transparent panel to form a closed sealed li~uid retaining chamber, and transparent coolant filling ~he sealed liquid retaini~g chamber; said heat radiator having a fin extending i~wardly from the inner wall thereof.
The other objects~ features and advantages of the pres2nt invention will become apparent from the ~ollowing description taken in con~unction with the accompa~ying drawings through which the like references designate the ~ame elements and parts.
. DESCRI~TION OF ~HE PREFERRED EMBODIMENT
An ~mbodiment of a cathode ray tube apparatus, or a liquid cooled cath~de ray tube apparatu~ ~ closed-oD~x~Dn . -8-~a~/~35S/~
type according to this invention will be descrlbed with reference to Fig. 2 and the following drawings.
In this invention, as shown in Fig. 2, a metal frame 10 is placed around the effective screen of the outside surface of the front panel la with the phosphor screen 7 on its inner surface of the cathocle ray tube envelope 1. A transparent panel 11 such as a glass plate and so on is opposed through the metal frame 10 to the front panel la with a predetermined spacing kept therebetween to form a li~uid~tight space 12 between both the panels 11 and la. Particularly the metal frame 10 is specially con-structed as will be described later more fully. The metal frame 10 is bonded in liquid-tight to the transparent panel 11 and the front panel la by resin adhesive 13 such as silicone resin and so on to thereby connect the metal frame 10 and the transparent panel 11 to the panel la mechanically.
Liquid coolant 13', for example, ethylene glycol aqueous solution is injected into and filled in the li~uid-tight space 12 between the transparent panel 11 and the front panel la.
Fig. 3 is a front view of the metal frame 10, Fig.
4 is a side view thereof and Fig. 5 i5 a cross-sectional view taken along the line A-A in Fig. 3. The metal frame 10 is formed of material having an excellent heat conduc-tivity, for example, aluminium of the die-cast manufacturing method and is interposed between the peripheral portions of the front panel la and the transparent panel 11 of the cathode ray tube envelope 1 to be a spacer for restricting a spacing between the panel la and the panel 11 in cooperation with the resin adhesive 13. The metal frame 10 comprises a 550~
frame-shape portion lOa having the outline corresponding to the outline of the front panel la of the cathode ray tube envelope 1, an annular-shape peripheral wall portion lOb (curved) along the (external) periphery of the (front) peripheral surface portion lal of the tube envelope 1, flange portions lOc extending outwardly from, for example, the opposing sides of the portion lOb, namely, in the direction substantially perpendicular to the tubular axis and having attaching screw bores 14 for attaching the cathode ray tube envelope 1 to its cabinet and so on, and a plurality of heat-radiation fins lOd each of which is planted in parallel one another on the flange portion lOc in the direction perpendicular thereto. Particularly in the present invention, at the inside e~ge of the frame portion lOa lS interposed between the panel 11 and the front panel la to define the spacing therebetween, namely, at the inside of the portion thereof which is bonded to the panels ll and la by the resin adhesive 13' a plate-shape protruded portion lOe having a thickness thinner than that of, for example, the frame portion lOa is provided to be protruded inwardly there-from over the substantially whole inner periphery of the frame portion lOa. This protruded portion lOe is arranged so as not to be coated with the resin adhesive 13. Further, due to the thickness of the resin adhesive 13 and/or the protruded portion lOe having its thickness reduced, the respective surfaces of the protruded portion lOe each of which faces to the panels 11 and la are opposed to the panels 11 and la so as to keep a spaciny therebetween. Almost all part of the protruded portion lOe is immersed into the liquid coolant 13' and hence almost all surface of the protruded ~2(:1 5~
portionlOe isindirect contact with the liquid coolant 13'.
The protruded portion lOe is formed to cover the substantially whole inner periphery of the frame portion lOa. In the illustrative embodiment, however, the protruded portion lOe has cutout portions lOf at its portions in which injection holes 15 are provided for injecting therethrough the liquid coolant 13l into the liquid-tight space 12. The protruded portion lOe is provided to be protruded inwardly from the whole inner periphery of the frame portion lOa except the .~
cutout portions lOf.
This metal frame 10 forms its protruded portion lOe outside the position of the effective picture screen shown by reference letter _ in Fig. 3. Even in this case, in order to prevent the light from the phosphor screen 7 being reflected by, for example, the protruded portion lOe of the metal frame lO to disturb the optical image, at least the surface of the protruded portion is made black. It is ....
desired that this blackening treatment will be performed, in practice, for the substantially whole surface of the metal frame lO to carry out the heat radiation and adsorb the heat from the liquid coolant 13' more effectively. When the metal frame 10 is made of aluminium, this blackening treatment can be performed by alumite treatment and further the use of dye, if necessary. In this case, when the surface of the metal frame 10 is electrically insulated by the blackening treat-ment, the surface treated by the blackening is removed in the portion where the observation of the optical image cannot be disturbed in which the liquid coolant 13' and the metal frame lO are electrically coupled to each other. That is, since the transparent liquid coolant 13' such as glycol -- 11 ~
5q~
and so on as described above has a certain electric con-ductivit~, if the liquid coolant 13' and the metal frame 10 are electrically connecked to each other, the panels 11 and la can be, for example,grounded through the liquid coolant 13' and the metal frame 10 to prevent the panels 11 and la from charging statically. For the resin adhesive 13 black silicone resin including, for example, black pigment can be used. If necessary, in order to present a predetermined - thickness of the silicone resin which will serve as the ., .
spacing between the panellland the front panel la in associa-tion with the frame portion lOa of the metal frame 10, hardened granular or annular elastic resin particles each of which has a predetermined thickness can be mixed into the resin adhesive 13.
According to the example of the present invention as described above, it was confirmed that the effect of heat radiation can be increased and in association therewith, the power o~ the cathode ray tube can be increased by 30 %
as compared with that of the conventional closed-convection type liquid cooled cathode ray tube apparatus while main-taining the present reliability. Now, let us examine the rise of temperature on the surface of the cathode ray tube versus cathode current Ik where anode voltage Vp applied to the phosphor screen 7 is selected to be 27 kV. Thenl it comes out as shown by a curve 16 in Fig. 6 according to this invention. As compared therewith, in the case of the prior art cathode ray tube apparatus described in connection with Fig. 1, or in the case where the metal frame 10 is not provided with the protruded portio~ which is immersed into the liquid coolant, the rise of temperature versus cathode .il 5~5~
current comes out as shown by a curve 17 in Fig. 6. Thus, with the same cathode current, or the same power, the cathode ray tube apparatus according to this invention can prevent the rise of temperature from being increased as compared with that of the prior art. As a result, it can be understood that according to this invention the power of the cathode ray tube can be increased under the state that a similar temper-ature to that in the prior art is permissible.
Table 1 indicates measured results of average temperatures of the li~uid coolant in the state that the temperature on the surface of the cathode ray tube reaches to the equilibrium state in the case where each example (comparative examples 1, 2 and 3) of the prior art cathode ray tube apparatus having the structure shown in Fig. 1 and each example ~examples 1, 2, 3 and 4) of the cathode ray tube apparatus according to this in~ention were respectively used continuously at the anode voltage Vp of 26 kV and the cathode current Ik of 430 ~A. In this table 1, the heat radiating area of each example which contacts with the air and the heat absorbing area of each example which contacts with the liquid coolant are indicated by relative values in which that in the comparative example 1 was taken as unit.
In the examples 1 to 4, the thickness of the frame portion lOa of each metal frame 10 is selected to be 3.8 mm and the thickness of the protruded portion lOe is selected to be 1 mm, while in the examples 1 and 2, the protruded length of the protruded portion lOe is selected to be 3 mm and those of the examples 3 and 4 are selected to be 5 mm.
~L 2~ 5R~
TABL:E 1 . ..
area of area of average heat radiation heat absorption temperature . _ _ comparatlve example 1 1 30 comparative example 2 2 1 27 10 ''- _ .
comparatlve example 3 _ 24 .
example 1 2 2 23 5 .
example 2 1 3.3 27.5 example 3 2 3.3 23 example ~ 6 3.3 17 As will be clear from the table 1, according to this invention, in accordance with the increase of the heat radiating area, the heat radiation can be substantially increased and the rise of temperature of the liquid coolant can be suppressed.
As set forth above, according to this invention, owing to the fact that the metal frame 10 placed between the transparent panel 11 and the front panel la of the cathode ray tube envelope 1 i5 provided with the protruded portion lOe which contacts with the liquid coolant 13', the heat radiating effect can be improved remarkably and the power of 5..51~
the cathode ray tube can be increased in association therewith, thus offering the cathode ray tube of higher brightness. Particularly in the color projector, as described before, it is possible to avoid the occurrence of thermal quenching in accordance with the suppress of the rise of temperature and therefore a color reproduced image can be obtained which has a white balance not disturbed, namely, which has hlgh color purity and is bright, resulting in enormous advantage in practical use.
Furthermore/ since the metal frame 10 is blackened and especially the protruded portion lOe which protrudes so as to be immersed into the liquid coolant 13' is blackened at its portion which will be observed at least from the front, the contrast of the reproduced picture can be improved and also the pi~ture quality can be avoided from being deterio-rated by the reflection of undesired light.~
The above description is given on a single pre-ferred embodiment of the invention, but it will be apparent that many modifications and variations could be effected b~
one skilled in the art without departing from the spirits or scope of the novel concepts of the invention, so that the scope of the invention should be determin~d by the appended claims only.
Field of the Invention This invention relates generally to a cathode ray tube apparatus and more particulaxly is directed to a cathode ray tube apparatus suitable for a high-brightness cathode ray tube used in, for example, color projectors.
Description of the Prior Art The high-brightness cathode ray tube is generally arranged such that the energy of an electron beam to impinge on its phosphor screen is increased to generate a reproduced optical image of high brightness. In this case, the heat generated by the impingement of the electron beam on the phosphor screen or in addition thereto, the heat generated by the impingement of electron beams on an electron beam landing position determining electrode such as a shadow mask, an aperture grille or the like which is provided within the tube envelope so as to oppose the phosphor screen for restricting the landing position of the electron beam on the phosphor screen becomes more conspicuous due to the increase of the energy of the electron beam. However, since the front panel or the glass panel of the tube envelope of the cathode ray tube on which the phosphor screen is formed has a low thermal conductivity, particularly in the continuous use, a significant rise of temperature occurs in the center of the front panel where it is difficult to radiate heat, thus causing a so-called thermal quenching in the phosphor. The thermal quenching is a phenomenon which causes the brightness of the phosphor to be lowered as the temperature increases.
O5~iO~
Since the degree of the thermal quenching is different depending on the phosphor of each color, the white balance is disturbed.
Since the disturbed white balance at the center of the front panel considarably degrades the picture quality, it may be considered to adjust the brightness of an optical image of each color so as to achieve the correct white balance at the center of the front panel during the continuous use. In this case, the white balance at the ., peripheries of the front panel is disturbed and also an overall brightness can not be increased.
This defect also appears in, for example, a color projector in either case where images of respective colors produced from respective monochromatic cathode ray tubes lS are mixed and projected onto a screen so as to obtain a color picture image or a color image formed of images of plural colors is obtained by the same cathode ray tube and then projected onto the screen.
In the high brightness cathode ray tube of this kind, in order to avoid the rise of temperature due to the continuous use which may cause the thermal quenching on the phosphor screen, it is necessary to cool the front panel.
The cooling of the front panel may be performed by a cooling fan. In this case, if such cooling operation is performed, a wind is blown to the front panel surface of the tube envelope and at the same time, dust is supplied to the panel surface. Such dust adheres to the panel surface to cause the brightness to be deteriorated apparently. Also, in this ~ case, the cooling fan may also cause noise.
In order to obviate such defects, a cathode ray ~3~
tube apparatus has been proposed in which a tr~nsparent liquid ~oolant or parti~ularly ~ liquid ccolant which easily causes a convection is located in contact with ~he front panel of the tube envelope of the cathode ray tube ~o as to cool the front p~nel.
BRIEF DESCRIPTION OF THE DR~WINt:S
~.
Fig. 1 is a partially cross~sectional side ~iew of a prior art liquid cooled cathode ray tube apparatus of closed-convection type;
lo Fig. 2 is a cross-sectional view of an embodiment of a cathode ray tube apparatus according to this invention;
. Fig. 3 is a front view of a metal Erame thereof;
Fig. 4 is a side view th.ereof;
Fig. 5 is a cros~-sectional view taken alsng the line A-A in Fig. 3; and Fig. 6 i~ a graph indicating temperature charac-t ristics on the ~urfac~ o~ the cathode ray tube envelope.
Fig. 1 i~ a partially cross-sectional side view of such previously propoæed liquid-cooling type ca~hode ray ~ube apparatu~ particularly a closed convec.tion type ~athode ray tube apparatus. As, for example r shown in ~ig. 1, fiuch cathode ray tube apparatus comprises a cathode r~y tube envelope 1 having a front panel la. A transparent panel 2 made of, for example, glass and having an optical transmis-~ivity is provided in front of the front panel la, and an annular metal frame 3 having an excellent thermal conduc-tivity is interposed between both ~he panel~ la and 2 along their peripheries wherein the metal frame 3 determines the .
spacing between the panels la and 2 and opposes them to each other. The peripheral portions of the metal frame 3, the outer surface of the panel la and the inner surface of the panel 2 are bonded together by resin adhesive agent 4 and sealed in liquid-tight to form a liquid-tight space 5 between the panels 2 and la. Transparent liquid coolant 6 which ea~ily causes a convection is fîlled into this li~uid-tight space 5. In Fig. 1, 7 designates -a~ phosphor screen formed on the inner surface of the panel la.
The cathode ray tube envelope 1 having such configuration is used under the state that the panel la is made substantially vertical.
In thi~ case, the liquid coolant 6 filled into the liquid-tight space 5 closely contacts with the front panel la of the cathode ray tube envelope 1 thexmally.
Therefore, according to such configuration of the conven-tio~al cathode ray tube appaxatus, when the rise of temperature occurs in the panel la, the liquid coolant 6 heated thereby moves upwards to cause the convection in the liquid-tight space 5. Thu~, even heat at, for example, the central portion of the panel la i5 effecti~ely moved to the peripheral portion thereof. This heat is then conducted to the metal frame 3 made of metal having 3 good heat con-ductivity, for example, aluminium which is pro~ided in the peripheries thereof with the result that the heat is conducted through the metal rame 3 and then radiated from the external peripheral poxtion o~ the metal ~rame 3 contacting with the . -5-~2~
open air.
- According ~ the cath~de ray tube apparatus thus arranged, it is possible to suppress the rise of temperature in the panel la relatively eiEfectively.
However, recently, the pro~ector has been requested to have high brightness and hi~h resolution of its cathod~
rsy tube and als~ requested to have a great power associated with high brightness, which then requires more and more eEfective heat radiation. Furthermore, when its accelerating voltage is increased in accordance with the pro~eckor having greater power ~power P is given by the equation expressed as P - Vp x Ik where Vp is the an~de voltage ~accelerating voltage) and Ik is the cathode current), the thic~ness of the ~ront panel la of the tube envelope 1 must be increased in order ~o avoid the increase of the X-ra~ transmission.
~owever, when the pro~ector employs particularly a plastic lens as its optical sy~tem~ a di~tance between the phosphor screen 7 and the lens, or ~he thickness of the ~ront pan~l la can not be increa~ed too much in view of the designing of the lens. Therefore, in this case, for a glass material of the transparent panel 2, it has been proposed to increase, fcr example, the lead content which has the shielding effect of X-ray. The glass containing a large amount of lead as described above is lowered in its hardness and is easily scratched. So, in this case, if the rise ~ temper-ature occurs as described before t~ cause the deformation such as bending due to thermal expansion in the txansparent panel 2, the transparent panel 2 may easily be broken.
~1l2~
Therefore, the higher brightness needs the more effective cooling by heat radiation.
For ~his reason, in the prior art ca~hode ray tube apparatus 9f the configuration as, for example, ~hown in Fig. l, for example, a heat radiation fin is provided to increase ~he surface area by which the metal frame 3 contacts with the air. ~owever, if it is done so, the heat radiation is not performed so effectively. As a result of various experiments and researches r the inventors of the present invention found out that the reason for that was that the heat of the li~uid coolant 6 was not ~ffectively conducted ~o thP metal frame 3. Namely, ~ince in practice the metal frame 3 was bonded in liquid-tight by the resin 4 to the panels 2 and la outside and inside surfaces of the portion int~rposed between both the panels 2 and la, the ~rea in which the metal frame 3 c~ntacts with the liquid coolant 6 was small and hence the heat of the liquid coolant 6 was not effectively conducted to ~he metal frame 3.
OBJECTS AND S~MMARY OF THE INVENTION
Accordingly, it is an ob~ect of this invention to provide a cathode ray tube apparatus capable vf obviating the afore-said defects inherent in the conventional cathode ray tube apparatus. :
Another object of this invention is to provide a cathode ray tube apparatus of high brightness which is free from a so-called thermal quenching.
Still another ob~ect of this invention is to provide a cathode ray tube apparatus of high brightness having a cathode ray tube capable of offering a high power 3 o and a high resolution.
iS~9 ~urther object o~ thi~ invention is to provide a cathode ray tube apparatus of high brightness which can perform more effeckive heat radiation and liquid cooling operations.
Still further ob~ect of this invention is to pr~vide a cathod~ ray tube apparatus of high brightness which can effectivel~ conduct heat of liquid coolant to a metal ~rame surrounding an effective picture screen.
Yet fur~h2r object of this invention is to provide a cathode ray tube apparatus suitable, ~or a cathode ray tube of high brightness employ~d for color projectors.
According to an aspect of this invention, *here i~ provided a liquid cooled cathode ray tube comprising a cathode ray tube'with a planar front panel coated with a phosphor screen, a metal heat radiator and ~pacer surrounding ~iaid planar ront pan~l, a planar transpaxent panel supported by said metal heat radiator,a spa~ed distance from said planar front panel, ~ealant on said planar suraces and sealing said heat radiator to said planar front panel and said planar transparent panel to form a closed sealed li~uid retaining chamber, and transparent coolant filling ~he sealed liquid retaini~g chamber; said heat radiator having a fin extending i~wardly from the inner wall thereof.
The other objects~ features and advantages of the pres2nt invention will become apparent from the ~ollowing description taken in con~unction with the accompa~ying drawings through which the like references designate the ~ame elements and parts.
. DESCRI~TION OF ~HE PREFERRED EMBODIMENT
An ~mbodiment of a cathode ray tube apparatus, or a liquid cooled cath~de ray tube apparatu~ ~ closed-oD~x~Dn . -8-~a~/~35S/~
type according to this invention will be descrlbed with reference to Fig. 2 and the following drawings.
In this invention, as shown in Fig. 2, a metal frame 10 is placed around the effective screen of the outside surface of the front panel la with the phosphor screen 7 on its inner surface of the cathocle ray tube envelope 1. A transparent panel 11 such as a glass plate and so on is opposed through the metal frame 10 to the front panel la with a predetermined spacing kept therebetween to form a li~uid~tight space 12 between both the panels 11 and la. Particularly the metal frame 10 is specially con-structed as will be described later more fully. The metal frame 10 is bonded in liquid-tight to the transparent panel 11 and the front panel la by resin adhesive 13 such as silicone resin and so on to thereby connect the metal frame 10 and the transparent panel 11 to the panel la mechanically.
Liquid coolant 13', for example, ethylene glycol aqueous solution is injected into and filled in the li~uid-tight space 12 between the transparent panel 11 and the front panel la.
Fig. 3 is a front view of the metal frame 10, Fig.
4 is a side view thereof and Fig. 5 i5 a cross-sectional view taken along the line A-A in Fig. 3. The metal frame 10 is formed of material having an excellent heat conduc-tivity, for example, aluminium of the die-cast manufacturing method and is interposed between the peripheral portions of the front panel la and the transparent panel 11 of the cathode ray tube envelope 1 to be a spacer for restricting a spacing between the panel la and the panel 11 in cooperation with the resin adhesive 13. The metal frame 10 comprises a 550~
frame-shape portion lOa having the outline corresponding to the outline of the front panel la of the cathode ray tube envelope 1, an annular-shape peripheral wall portion lOb (curved) along the (external) periphery of the (front) peripheral surface portion lal of the tube envelope 1, flange portions lOc extending outwardly from, for example, the opposing sides of the portion lOb, namely, in the direction substantially perpendicular to the tubular axis and having attaching screw bores 14 for attaching the cathode ray tube envelope 1 to its cabinet and so on, and a plurality of heat-radiation fins lOd each of which is planted in parallel one another on the flange portion lOc in the direction perpendicular thereto. Particularly in the present invention, at the inside e~ge of the frame portion lOa lS interposed between the panel 11 and the front panel la to define the spacing therebetween, namely, at the inside of the portion thereof which is bonded to the panels ll and la by the resin adhesive 13' a plate-shape protruded portion lOe having a thickness thinner than that of, for example, the frame portion lOa is provided to be protruded inwardly there-from over the substantially whole inner periphery of the frame portion lOa. This protruded portion lOe is arranged so as not to be coated with the resin adhesive 13. Further, due to the thickness of the resin adhesive 13 and/or the protruded portion lOe having its thickness reduced, the respective surfaces of the protruded portion lOe each of which faces to the panels 11 and la are opposed to the panels 11 and la so as to keep a spaciny therebetween. Almost all part of the protruded portion lOe is immersed into the liquid coolant 13' and hence almost all surface of the protruded ~2(:1 5~
portionlOe isindirect contact with the liquid coolant 13'.
The protruded portion lOe is formed to cover the substantially whole inner periphery of the frame portion lOa. In the illustrative embodiment, however, the protruded portion lOe has cutout portions lOf at its portions in which injection holes 15 are provided for injecting therethrough the liquid coolant 13l into the liquid-tight space 12. The protruded portion lOe is provided to be protruded inwardly from the whole inner periphery of the frame portion lOa except the .~
cutout portions lOf.
This metal frame 10 forms its protruded portion lOe outside the position of the effective picture screen shown by reference letter _ in Fig. 3. Even in this case, in order to prevent the light from the phosphor screen 7 being reflected by, for example, the protruded portion lOe of the metal frame lO to disturb the optical image, at least the surface of the protruded portion is made black. It is ....
desired that this blackening treatment will be performed, in practice, for the substantially whole surface of the metal frame lO to carry out the heat radiation and adsorb the heat from the liquid coolant 13' more effectively. When the metal frame 10 is made of aluminium, this blackening treatment can be performed by alumite treatment and further the use of dye, if necessary. In this case, when the surface of the metal frame 10 is electrically insulated by the blackening treat-ment, the surface treated by the blackening is removed in the portion where the observation of the optical image cannot be disturbed in which the liquid coolant 13' and the metal frame lO are electrically coupled to each other. That is, since the transparent liquid coolant 13' such as glycol -- 11 ~
5q~
and so on as described above has a certain electric con-ductivit~, if the liquid coolant 13' and the metal frame 10 are electrically connecked to each other, the panels 11 and la can be, for example,grounded through the liquid coolant 13' and the metal frame 10 to prevent the panels 11 and la from charging statically. For the resin adhesive 13 black silicone resin including, for example, black pigment can be used. If necessary, in order to present a predetermined - thickness of the silicone resin which will serve as the ., .
spacing between the panellland the front panel la in associa-tion with the frame portion lOa of the metal frame 10, hardened granular or annular elastic resin particles each of which has a predetermined thickness can be mixed into the resin adhesive 13.
According to the example of the present invention as described above, it was confirmed that the effect of heat radiation can be increased and in association therewith, the power o~ the cathode ray tube can be increased by 30 %
as compared with that of the conventional closed-convection type liquid cooled cathode ray tube apparatus while main-taining the present reliability. Now, let us examine the rise of temperature on the surface of the cathode ray tube versus cathode current Ik where anode voltage Vp applied to the phosphor screen 7 is selected to be 27 kV. Thenl it comes out as shown by a curve 16 in Fig. 6 according to this invention. As compared therewith, in the case of the prior art cathode ray tube apparatus described in connection with Fig. 1, or in the case where the metal frame 10 is not provided with the protruded portio~ which is immersed into the liquid coolant, the rise of temperature versus cathode .il 5~5~
current comes out as shown by a curve 17 in Fig. 6. Thus, with the same cathode current, or the same power, the cathode ray tube apparatus according to this invention can prevent the rise of temperature from being increased as compared with that of the prior art. As a result, it can be understood that according to this invention the power of the cathode ray tube can be increased under the state that a similar temper-ature to that in the prior art is permissible.
Table 1 indicates measured results of average temperatures of the li~uid coolant in the state that the temperature on the surface of the cathode ray tube reaches to the equilibrium state in the case where each example (comparative examples 1, 2 and 3) of the prior art cathode ray tube apparatus having the structure shown in Fig. 1 and each example ~examples 1, 2, 3 and 4) of the cathode ray tube apparatus according to this in~ention were respectively used continuously at the anode voltage Vp of 26 kV and the cathode current Ik of 430 ~A. In this table 1, the heat radiating area of each example which contacts with the air and the heat absorbing area of each example which contacts with the liquid coolant are indicated by relative values in which that in the comparative example 1 was taken as unit.
In the examples 1 to 4, the thickness of the frame portion lOa of each metal frame 10 is selected to be 3.8 mm and the thickness of the protruded portion lOe is selected to be 1 mm, while in the examples 1 and 2, the protruded length of the protruded portion lOe is selected to be 3 mm and those of the examples 3 and 4 are selected to be 5 mm.
~L 2~ 5R~
TABL:E 1 . ..
area of area of average heat radiation heat absorption temperature . _ _ comparatlve example 1 1 30 comparative example 2 2 1 27 10 ''- _ .
comparatlve example 3 _ 24 .
example 1 2 2 23 5 .
example 2 1 3.3 27.5 example 3 2 3.3 23 example ~ 6 3.3 17 As will be clear from the table 1, according to this invention, in accordance with the increase of the heat radiating area, the heat radiation can be substantially increased and the rise of temperature of the liquid coolant can be suppressed.
As set forth above, according to this invention, owing to the fact that the metal frame 10 placed between the transparent panel 11 and the front panel la of the cathode ray tube envelope 1 i5 provided with the protruded portion lOe which contacts with the liquid coolant 13', the heat radiating effect can be improved remarkably and the power of 5..51~
the cathode ray tube can be increased in association therewith, thus offering the cathode ray tube of higher brightness. Particularly in the color projector, as described before, it is possible to avoid the occurrence of thermal quenching in accordance with the suppress of the rise of temperature and therefore a color reproduced image can be obtained which has a white balance not disturbed, namely, which has hlgh color purity and is bright, resulting in enormous advantage in practical use.
Furthermore/ since the metal frame 10 is blackened and especially the protruded portion lOe which protrudes so as to be immersed into the liquid coolant 13' is blackened at its portion which will be observed at least from the front, the contrast of the reproduced picture can be improved and also the pi~ture quality can be avoided from being deterio-rated by the reflection of undesired light.~
The above description is given on a single pre-ferred embodiment of the invention, but it will be apparent that many modifications and variations could be effected b~
one skilled in the art without departing from the spirits or scope of the novel concepts of the invention, so that the scope of the invention should be determin~d by the appended claims only.
Claims (3)
1. A liquid cooled cathode ray tube comprising a cathode ray tube with a transparent planar front panel coated with a phosphor screen, a generally annular metal heat radiator supported by said front panel at the outer periphery of the panel, a planar transparent panel supported at the outer periphery thereof by said metal heat radiator a spaced distance from said planar front panel, sealant on said planar surfaces and cooperating support surfaces on said annular heat radiator and sealing said heat radiator to the outer periphery of said planar transparent panel to form a closed sealed liquid retaining chamber, and trans-parent coolant filling the sealed liquid retaining chamber;
said metal heat radiator having a fin projecting radially inwardly from the annular wall thereof, said fin being wet on both sides by said coolant.
said metal heat radiator having a fin projecting radially inwardly from the annular wall thereof, said fin being wet on both sides by said coolant.
2. A liquid cooled cathode ray tube according to claim 1, wherein the thickness of said fin is made substan-tially smaller than that of said metal radiator whereby both sides of the fin extend into the coolant in heat transfer relation with a substantial volume of said coolant.
3. A liquid cooled cathode ray tube according to claim 2 wherein said metal heat radiator is blackened.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP101550/82 | 1982-06-14 | ||
| JP57101550A JPS58218734A (en) | 1982-06-14 | 1982-06-14 | Cathode-ray tube device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1205509A true CA1205509A (en) | 1986-06-03 |
Family
ID=14303532
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000429864A Expired CA1205509A (en) | 1982-06-14 | 1983-06-07 | Cathode ray tube apparatus |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS58218734A (en) |
| KR (1) | KR900003216B1 (en) |
| AU (1) | AU564241B2 (en) |
| CA (1) | CA1205509A (en) |
| DE (1) | DE3321489A1 (en) |
| FR (1) | FR2528624B1 (en) |
| GB (1) | GB2124425B (en) |
| NL (1) | NL8302119A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58154146A (en) * | 1982-03-10 | 1983-09-13 | Sony Corp | Liquid cooling type cathode-ray tube |
| JPS59157938A (en) * | 1983-02-24 | 1984-09-07 | Sony Corp | Cathode ray tube device |
| JPS603548U (en) * | 1983-06-20 | 1985-01-11 | ソニー株式会社 | cathode ray tube device |
| DE3474484D1 (en) * | 1984-06-01 | 1988-11-10 | Philips Patentverwaltung | Projection cathode ray tube |
| JPS62169448U (en) * | 1986-04-17 | 1987-10-27 | ||
| JPH0658474B2 (en) * | 1989-09-04 | 1994-08-03 | カシオ計算機株式会社 | Liquid crystal display |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2241974A (en) * | 1938-04-05 | 1941-05-13 | Gen Electric | High power cathode ray device |
| JPS597731Y2 (en) * | 1979-06-07 | 1984-03-09 | ソニー株式会社 | cathode ray tube equipment |
| JPS57180957U (en) * | 1981-05-12 | 1982-11-16 | ||
| JPS58154145A (en) * | 1982-03-09 | 1983-09-13 | Sony Corp | Cathode-ray tube |
| JPS58154146A (en) * | 1982-03-10 | 1983-09-13 | Sony Corp | Liquid cooling type cathode-ray tube |
| JPS58182250U (en) * | 1982-05-28 | 1983-12-05 | 日本電気ホームエレクトロニクス株式会社 | projection cathode ray tube |
-
1982
- 1982-06-14 JP JP57101550A patent/JPS58218734A/en active Granted
-
1983
- 1983-06-07 CA CA000429864A patent/CA1205509A/en not_active Expired
- 1983-06-08 AU AU15617/83A patent/AU564241B2/en not_active Expired
- 1983-06-09 KR KR1019830002572A patent/KR900003216B1/en not_active Expired
- 1983-06-10 GB GB08315993A patent/GB2124425B/en not_active Expired
- 1983-06-14 NL NL8302119A patent/NL8302119A/en active Search and Examination
- 1983-06-14 FR FR8309833A patent/FR2528624B1/en not_active Expired
- 1983-06-14 DE DE3321489A patent/DE3321489A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| AU564241B2 (en) | 1987-08-06 |
| GB8315993D0 (en) | 1983-07-13 |
| JPH0139182B2 (en) | 1989-08-18 |
| KR840005275A (en) | 1984-11-05 |
| FR2528624B1 (en) | 1986-10-10 |
| GB2124425B (en) | 1986-03-26 |
| FR2528624A1 (en) | 1983-12-16 |
| KR900003216B1 (en) | 1990-05-10 |
| NL8302119A (en) | 1984-01-02 |
| GB2124425A (en) | 1984-02-15 |
| JPS58218734A (en) | 1983-12-20 |
| AU1561783A (en) | 1983-12-22 |
| DE3321489A1 (en) | 1983-12-15 |
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| MKEX | Expiry |